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10,817,172 | ACCEPTED | System for treatment of plantar fasciitis | An stretch resistant plantar fascia support system is provided. The stretch resistant plantar fascia support system is adhesively applied to the foot of a patient for providing relief from plantar fasciitis. A portion of the stretch resistant plantar fascia support system is adhesively attached to the bottom surface of the foot for reducing stress on the plantar fascia. | 1. A method for managing stress on a plantar fascia of a human foot including: providing a support device, wherein at least a portion of said support device is pre-shaped to be conformed for use with the foot; adhering at least a portion of said support device to the foot using an adhesive; and controlling tension in at least a portion of the plantar fascia of the foot, wherein said step of controlling includes sharing the tensile forces applied to the plantar fascia from the forces on an arch of the foot which push the bones of the foot downwardly, said sharing being among the plantar fascia and said support device. 2. The method of claim 1 wherein the step of adhering at least a portion of said support device includes: applying said adhesive to the foot; and pressing said support device against said adhesive. 3. The method of claim 1 wherein the step of adhering at a least a portion of said support device includes: applying said adhesive to the support device; and pressing said support device against the foot. 4. The method of claim 1 wherein the step of adhering at least a portion of said support device includes adhering a foot sole support to at least a portion of a sole of the foot, wherein at least a portion of said foot sole support is substantially stretch resistant. 5. The method of claim 4 wherein the step of adhering at least a portion of said support device includes adhering at least a portion of said foot sole support on the foot extending from the heel of the foot to the ball of the foot, wherein said foot sole support has a thickness of less than 30 mils. 6. The method of claim 4 wherein the step of adhering at least a portion of said support device includes wrapping an arch strap over an arch of the foot, wherein said arch strap is attached to said foot sole support. 7. The method of claim 4 wherein the step of adhering at least a portion of said support device includes adhering a heel strap to at least a portion of a heel of the foot, wherein said heel strap is attached to said foot sole support. 8. The method of claim 4 wherein the step of adhering at least a portion of said support device includes wrapping a front strap laterally across the foot near a ball of the foot, wherein said front strap is attached to said foot sole support. 9. The method of claim 1 including: removing a protective cover from said support device, wherein said protective cover is removably adhered to said adhesive. 10. The method of claim 1 wherein said support device includes indicia that indicate the order in which portions of said support device are attached to the foot. 11. The method of claim 4 including: transporting moisture from a surface of the foot positioned between said foot sole support and the foot, wherein at least a portion of said foot sole support is made of a permeable material and the moisture is transported through said permeable material. 12. A system for managing pain in a human foot including: a support device, wherein at least a portion of said support device is substantially stretch resistant; an adhesive; and a removable protective cover over at least a portion of the adhesive, wherein said protective cover is removed from said adhesive and said adhesive affixes at least a portion of said support device to the foot, whereby tension is shared between the plantar fascia and said support device to control the stress in at least a portion of the plantar fascia. 13. The system of claim 12 wherein said support device includes a foot sole support affixed to at least a portion of a sole of the foot, wherein said foot sole support is pre-shaped to match the sole of the foot. 14. The system of claim 12 wherein said support device includes a sole portion that is substantially stretch resistant and includes at least one tab and at least one strap that are affixed to the foot generally transversely to said sole portion. 15. The system of claim 13 wherein said support device includes an arch strap wrapped over an arch of the foot, wherein said arch strap is attached to said foot sole support. 16. The system of claim 13 wherein said support device includes a heel strap adhered to at least a portion of a heel of the foot, wherein said heel strap is attached to said foot sole support. 17. The system of claim 13 wherein said support device includes a front strap wrapped laterally across the foot near a ball of the foot. 18. The system of claim 12 wherein said support device includes at least one removable protective cover, wherein said at least one removable protective cover is removably adhered to said adhesive. 19. The system of claim 12 wherein said support device includes indicia that indicate the order in which portions of said support device are to be attached to the foot. 20. The system of claim 12 wherein said support device is made of a permeable material that allows moisture to move from the surface of the foot through said permeable material. 21. The method of claim 1, wherein said method includes treating pain in at least one of the heel, or arch or ball of the foot. 22. The method of claim 1, wherein said controlling step includes preventing extension and stretching of the plantar fascia of the foot. 23. The method of claim 1, wherein said controlling step includes reducing tension on the plantar fascia of the foot. 24. The method of claim 1, wherein at least a portion of said support device is made of a plurality of materials which in combination are substantially stretch resistant. 25. The system of claim 12, wherein said support device is affixed to the foot to treat pain in at least one of the heel, or arch or ball of the foot. 26. The system of claim 12, wherein said support device prevents extension and stretching of the plantar fascia of the foot. 27. The system of claim 12, wherein said support device reduces tension on the plantar fascia of the foot. 28. The system of claim 12, wherein at least a portion of said support device is made of a plurality of materials which in combination are substantially stretch resistant. 29. The method of claim 1, wherein said support device includes a plurality of protective covers and wherein said method further includes removing said plurality of protective covers from the support device in order to adhere the support device to the foot. 30. The system of claim 12 further comprising a plurality of protective covers removably joined to said support device. 31. The method of claim 1, wherein said support device includes a plurality of straps and wherein said step of adhering at least a portion of the support device to the foot includes adhering said plurality of straps to the foot generally transversely to the support device to secure the support device to the foot. 32. The system of claim 12 further including a plurality of straps that are affixed to the foot generally transversely to said support device. 33. The method of claim 1, wherein said support device includes a foot sole support that is pre-shaped in accordance with the shape of the sole of the foot and wherein the step of adhering at least a portion of the support device to the foot includes adhering said foot sole support to at least a portion of the sole of the foot. 34. The system of claim 12, wherein said support device includes a foot sole support that is pre-shaped in accordance with the shape of the sole of the foot, said foot sole support being affixed to at least a portion of the sole of the foot. 35. The method of claim 1, wherein said method further includes providing at least one strap and adhering said at least one strap to the foot separately from the support device. 36. The system of claim 12, further including at least one strap that is affixed to the foot separately from said support device. 37. The method of claim 1, wherein said support device includes medicinal additives and wherein the step of adhering at least a portion of the support device to the foot includes applying said medicinal additives included in the support device to the foot. 38. The system of claim 12, wherein said support device includes at least one of medicinal additives, anti-fungal treatments, anti-microbial treatments, anti-inflammatory treatments, deodorants, and tea tree oil. 39. The method of claim 1, further providing an arch strap on the support device, wherein the support device has a thickness of less than 30 mils, an adhesive, and a protective cover, wherein said step of adhering at least a portion of said support device includes wrapping the arch strap over the arch of the foot. 40. The system of claim 12, wherein said support device includes a Rayon fabric having a thickness of less than 30 mils, an adhesive, and a protective cover and said support device includes an arch strap that is wrapped over the arch of the foot. 41. The method of claim 5, wherein said method further includes providing at least one strap and adhering said at least one strap generally transversely to said support device between the heel of the foot and ball of the foot, wherein said strap is less than 30 mils thick. 42. The system of claim 12, wherein said support device includes holes to allow evaporation of moisture away from the foot. 43. The method of claim 1, wherein said support device is a of generally uniform thickness having holes that allow moisture to evaporate away from the foot. | BACKGROUND OF THE INVENTION The present invention generally relates to a stretch resistant plantar fascia support system. More particularly, the present invention relates to a stretch resistant plantar fascia support system that may be adhesively applied to a foot to provide relief from plantar fasciitis. FIG. 1 is a dissected bottom view of a human foot 100 provided to illustrate some of the parts of a plantar fascia 110 located in the bottom of the human foot 100. As shown in FIG. 1, the plantar fascia 110 extends from about the location of the heel 101 to about the location of the ball 102 of the foot. The plantar fascia 110 includes medial plantar fascia 120, superficial tracts 130, a central component of the plantar fascia 140, and a lateral component of the plantar fascia 150. The separate portions of the plantar fascia 110 act as a shock absorber while walking and transfer tensile forces along the bottom of the foot 100. FIG. 2 illustrates a simplified side view of tissue and bone structure in the human foot 100. As shown in FIG. 2, the human foot 100 includes the plantar fascia 110, a plantar calcaneus 160, a talus 162, a navicular 164, a cuneiform 166, a cuboid 168, metatarsals 170, phalanges 172, a sesamoid 174, a fat pad area 176, and an outer skin surface 178. From the side view in FIG. 2, the plantar calcaneus 160, the talus 162, the navicular 164, the cuneiform 166, the cuboid 168, the metatarsals 170, and the sesamoid 174 form what resembles the shape of an arch. This shape is commonly referred to as the longitudinal arch. Another arch commonly referred to as the transverse arch (metatarsal) also exists in about the same area in a perpendicular direction that runs laterally across the width of the foot. The plantar fascia 110 serves the vital role of maintaining the shape of the two anatomical arches of the foot, the transverse arch and the longitudinal arch. As illustrated in FIGS. 1 and 2, the plantar fascia 110 runs across the bottom of the foot 100 from the heel 101 to the ball 102 and spreads out across the width of the foot 100. As longitudinal and lateral tensile stresses are produced in the bottom of the foot 100, the plantar fascia 110 absorbs the tensile forces and maintains the shape of the two anatomical arches. For example, while standing or while in motion, forces experienced by the foot 100 act in a direction which tends to flatten the arches. The stress line 300 in FIG. 2 shows an approximation of the line of forces transferred through foot 100 during typical motion. As shown in FIG. 2, the stress line 300 resembles the shape of an archer's bow. The plantar fascia 110 running along near the bottom surface of the foot 100 is analogous to a string in the archer's bow. Forces that tend to move the ends of the bow apart increase tension on the string. In other words, as forces on the arch push the bones downward, the plantar fascia 110 is subjected to tensile forces. If the tension on the plantar fascia 110 becomes excessive, the plantar fascia 110 may be damaged and produce a condition called plantar fasciitis. Plantar fasciitis is a painful medical condition resulting from inflammation of the plantar fascia 110. The plantar fascia 110 is thick and essentially inelastic. Overstressing the plantar fascia 110 may produce tears in the plantar fascia 110 or separate the plantar fascia 110 from bone and other surrounding materials. Tearing and separation of the plantar fascia 110 produces the painful inflammation known as plantar fasciitis. Frequently, the inflamed areas 305 are along the arch of the foot 100 or near the heel 101 of the foot 100 as shown in FIG. 2. Plantar fasciitis may be quite debilitating in that everyday activities such as walking and standing may be very painful. Typical treatments for plantar fasciitis may involve oral anti-inflammatories, ice packs, bedrest, stretching, steroid injections, night splints and wedge-shaped arch supports. In extreme cases, treatment of plantar fasciitis may require corrective surgery. For example, a design for an orthotic device for treatment of plantar fasciitis is disclosed in Gleason, U.S. Pat. No. 5,865,779. The device of Gleason is an elastic sock that is worn on a patient's foot. The elastic sock exerts compressive forces along the longitudinal and transverse axes of the patient's foot. While some patients may be willing to wear an elastic sock, the elastic sock is both inconvenient and cumbersome. In order to be installed on the foot, the elastic sock must be stretched to fit over the heel and toe of the foot. Because the sock is elastic, the sock allows the foot to move and stretch. Consequently, the plantar fascia may still be subjected to excessive tensile forces during the critical heeling process. Re-subjecting the plantar fascia to tensile forces before it has completely healed may re-aggravate damaged portions of the plantar fascia and undermine the healing process. In addition, the elastic sock is meant to be worn multiple times and may require regular cleaning to avoid odors and foot infections. Also, the sock may not fit inside a shoe while being worn and may be considered unsightly while walking around with bare feet. Consequently, the elastic sock does not prevent excessive stretching of the plantar fascia and is both inconvenient and cumbersome. Another typical example of treatment for plantar fasciitis includes medical personnel strapping strips of tape to the bottom of an injured foot. Strips of tape are applied at various angles across the bottom of the foot. The tape is difficult to remove from the rolls and bunches up during the taping process. Thus, care must be exercised during the application of the tape to avoid blister-causing wrinkles in the tape and other problems. As the patient walks with the taped foot, the tape works loose and stretches with time. In addition, the tape cannot be effectively applied by the patient to the patient's own foot and requires application by another individual such as a trained medical technician. Consequently, taping the foot is cumbersome, inefficient, and ineffective in preventing excessive stretching of the plantar fascia. Sometimes when current methods of treatment for plantar fasciitis are ineffective, expensive surgical procedures are required to relieve the pain of plantar fasciitis. To get at the plantar fascia, surgeons may perform either an endoscopic procedure requiring small incisions or conventional direct visualization requiring the underside of the foot to be opened up. With either painful procedure, scars may result and recovery time may be from weeks to months. Even with treatment, improper treatment of plantar fasciitis may lead to other medical problems. For example, if inflammation near the heel is allowed to continue for a long period of time, calcium deposits may build-up in the damaged region. As the calcium builds-up, bony outcroppings may develop in the heel that are commonly referred to as “heel spurs”. The longer the plantar fascia remains inflamed around the heel, the stronger the conditions are for the development of heel spurs. Protrusion of the heel spurs into the surrounding tissue may result in a cycle of irritation, inflammation, and pain known as heel spur syndrome. Heel spur syndrome is commonly treated with a surgical procedure requiring removal of the heel spurs from within the foot. An endoscopic procedure is typically not used for removal of heel spurs and open surgery is typically required. Recovery time from such surgery may range from weeks to months, during which time the patient has to curtail the amount of stress placed on the foot. Thus, it may be highly desirable to have a system for avoiding and/or treating the pain of plantar fasciitis. It may also be highly desirable to have a system for treating plantar fasciitis that is economical and may be easily applied by the patient. It may also be highly desirable to have a system for treating plantar fasciitis that is discretely attached to the sole of the patient's foot and includes a substantially stretch resistant material to reduce tensile forces in the plantar fascia. BRIEF SUMMARY OF THE INVENTION A preferred embodiment of the present invention provides a system for treatment of plantar fasciitis. The system is economical and may be easily applied by a patient. A stretch resistant plantar fascia support system is provided with a foot sole support. The foot sole support may be a thin one-piece device made of a uniform substantially stretch resistant material of a uniform thickness or the foot sole support may be made with a strip of substantially stretch resistant material bounded by a more deformable material. The foot sole support may be shaped to conform to the outline of the bottom of a foot or shaped to cover only a portion of the bottom of a foot. Straps and tabs may be included with the foot sole support for providing additional support to both the foot and other portions of the stretch resistant plantar fascia support system. The foot sole support, straps, and tabs have adhesive applied to portions of the surface of the foot sole support, the straps, and the tabs. Removable protective covers are applied over the adhesive and the removable protective covers may include indicia signifying the order in which the portions of the stretch resistant plantar fascia support system are to be applied to the foot. To relieve the symptoms of plantar fasciitis, tensile stresses in the plantar fascia are reduced. The tensile stresses in the plantar fascia are reduced by adhering the foot sole support to the foot of the patient. The foot sole support absorbs tensile stress in the lower foot thereby reducing the tensile stress experienced by the plantar fascia and surrounding tissues. The straps and tabs may be attached in the prescribed order to the foot sole support and wrapped around or attached to portions of the foot to provide additional support to the stretch resistant plantar fascia support system. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates parts of a plantar fascia in a dissected bottom view of a human foot. FIG. 2 illustrates a simplified side view of tissue and bone structure in the human foot. FIG. 3 illustrates a stretch resistant plantar fascia support system in accordance with an embodiment of the present invention. FIG. 4 illustrates a stretch resistant plantar fascia support system in accordance with an alternative embodiment of the present invention. FIG. 5 illustrates stresses in the human foot with a stretch resistant plantar fascia support system installed in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION FIG. 3 illustrates a stretch resistant plantar fascia support system 400 in accordance with an embodiment of the present invention. The stretch resistant plantar fascia support system 400 includes a foot sole support 410, an adhesive layer 411, indicia 415, removable protective covers 416, arch straps 420, heel strap 430, heel strap tabs 432, toe strap 440, toe strap tab 442, front straps 450, and heel tabs 460. The arch straps 420, the heel strap 430, the toe strap 440, the front straps 450, and the heel tabs 460 are connected to the foot sole support 410. The arch straps 420 project from the sides of the foot sole support 410 approximately midway along the longitudinal axis of the foot sole support 410. The heel strap 430 projects from the back edge of the foot sole support 410 and the heel strap tabs 432 project from the sides of the heel strap 430. The toe strap 440 projects from the front edge of the foot sole support 410 and the toe strap tab projects from a side of the toe strap 440. The front straps 450 project from the sides of the of the foot sole support 410 adjacent the front edge of the foot sole support 410. The heel tabs 460 project from the sides of the foot sole support 410 adjacent the back edge of the foot sole support 410. The adhesive layer 411 is applied to the top or inner surface of the foot sole support 410, the arch straps 420, the heel strap 430, the toe strap 440, the front straps 450, and the heel tabs 460. The removable protective covers 416 are removably adhered to the adhesive layer 411. Indicia 415 are printed on the removable protective covers 416. In operation, the stretch resistant plantar fascia support system 400 is adhesively attached to a human foot 100. To adhesively attach the stretch resistant plantar fascia support system 400 to the human foot 100, the removable protective cover 416 adhered to the top of the foot sole support 410 is removed. The foot sole support 410 is pressed against the outer skin surface 178 on the bottom of the human foot 100. Adhesion of the foot sole support 410 to the outer skin surface 178 on the bottom of the human foot 100 prevents extension and stretching of tissue on the bottom of the foot. By restricting extension of the tissue on the bottom of the foot, the level of tensile stress on the plantar fascia is reduced. In the alternative, adhesive may be applied to select portions of the foot sole support 410, the straps 420, 430, 440 and 450, and the tabs 432, 442, and 462. For example, to reduce the chance of irritation to sensitive skin regions along an arch of the foot or to accommodate users with high arches, adhesive may only be applied to the portion of the foot sole support 410 contacting the ball of the foot and the heel of the foot. In another alternative embodiment, adhesive may be applied to the sole of the foot. For example, adhesive sprays may be used to spray an adhesive layer on select portions of the foot. If a strong enough adhesive spray is used that would hold the foot sole portion 410 in place, then the stretch resistant plantar fascia support system 400 may be supplied without the adhesive layer 411 and removable protective covers 416. To help maintain the position of the foot sole support 410 on the bottom of the human foot 100 and further reduce tensile stress on the plantar fascia, the arch straps 420 may be wrapped laterally over the arch of the foot. To install the arch straps 420, the removable protective cover 416 adhered to the inner surface of the arch straps 420 is removed. The arch straps 420 are then wrapped up and over the top of the foot 100. To secure the arch straps 420 in place, one of the arch straps 420 may overlap another arch strap 420 and be adhered to the outer surface of the other arch strap 420. In the alternative, only one arch strap 420 may be used. With only one arch strap 420, the arch strap 420 may wrap laterally over the top of the arch and adhere to the bottom surface of the foot sole support 410 on the opposite side of the foot 100. In another alternative embodiment, only one arch strap 420 may be used and the arch strap 420 may be separate and distinct from the foot sole support 410. With the foot sole support 410 already installed on the bottom of the foot 100, the arch strap 420 may be adhered to the foot sole support 410 on one side of the foot 100. The arch strap 420 may then be wrapped laterally over the arch, down the opposite side of the foot 100, and adhered to the foot sole support 410 on the opposite side of the foot 100. Installation of the arch straps 420 also reduces stress on the plantar fascia. As presented earlier with regard to FIG. 2, the stress line 300 in FIG. 2 resembles an archer's bow. The stress line 300 passes through the talus 162, the navicular 164, the cuneiform 166, and the cuboid 168. Laterally wrapping the arch straps 420 over and around the top of the foot near the arch provides resistance to vertical and lateral movement of the talus 162, the navicular 164, the cuneiform 166, and the cuboid 168. Provision of the resistance to vertical and lateral movement by the arch straps 420 reduces flexure of the “bow” and related changes in stress on the plantar fascia. To provide extra support to the heel of the human foot 100 and help maintain the position of the foot sole support 410 on the bottom of the human foot 100, the heel strap 430 may be adhered to the heel of the foot 100. To further support the heel and help maintain the position of the foot sole support 410, the heel strap 430 includes heel strap tabs 432. To install the heel strap 430 and heel strap tabs 432, the removable protective cover 416 adhered to the inner surface of the heel strap 430 and heel strap tabs 432 are removed. The heel strap 430 is then pressed against the back of the heel of the foot 100 and secured in place by contact between the adhesive layer 411 and the outer skin surface 178. The heel strap tabs 432 are pressed against the outer skin surface 178 along the sides of the heel of the foot 100. In an alternative embodiment, the stretch resistant plantar fascia support system 400 may include a heel strap 430 without heel strap tabs 432. The heel strap 430 may be installed as described above by removing the removable protective cover 416 and adhering the heel strap 430 to the back of the heel. Installation of the heel strap 430 provides extra support to the heel and helps maintain the position of the foot sole support 410. Adhesion of the heel strap 430 to the back of the heel provides an anchor point for the rear portion of the foot sole support 410. During the course of walking, the foot sole support 410 may be subjected to lateral and longitudinal forces from contact between the foot sole support 410 and other surfaces such as the interior of shoes or floor surfaces. Depending on the level of the lateral and longitudinal forces, the resistance to lateral and longitudinal forces provided by the adhesive layer 411 may be exceeded. Adhering the heel strap 430 to the heel of the foot 100 provides extra resistance to lateral and longitudinal forces that may otherwise cause the foot sole support 410 to shift around on the bottom of the foot. Additionally, the heel strap 430 provides extra support to the heel of the foot 100. The human foot has a complex structure of tissue and bones. Tissues in the heel interact with other tissues in the foot to transfer forces exhibited during walking. As shown in FIG. 1, portions of the plantar fascia attach to the heel and other tissues that continue up around the back of the heel. Through these attachments, tissues in the heel transfer forces to and from the plantar fascia. Providing extra support to the heel of the foot 100 reduces the amount of stress transferred between the heel and the plantar fascia. The stretch resistant plantar fascia support system 400 also includes heel tabs 460. Similar to the heel strap 430, the heel tabs 460 assist in maintaining the position of the foot sole support 410. To install the heel tabs 460, the removable protective covers 416 adhered to the inner surface of the heel tabs 460 are removed. The heel tabs 460 are then pressed against the sides of the heel of the foot 100 and secured in place by contact between the adhesive layer 411 and the outer skin surface 178. As the foot sole support 410 is subjected to lateral and longitudinal forces, the heel tabs 460 provide additional resistance to the lateral and longitudinal forces to help maintain the installed position of the foot sole support 410. The stretch resistant plantar fascia support system 400 also includes front straps 450. The front straps 450 assist in maintaining the position of the foot sole support 410 and provide extra support to the area near the ball of the foot 100. To install the front straps 450, the removable protective covers 416 adhered to the inner surface of the front straps 450 are removed. The front straps 450 are then wrapped up and over the top of the foot 100. To secure the front straps 450 in place, one of the front straps 450 may overlap another front strap 450 and be adhered to the outer surface of the other front strap 450. In the alternative, only one front strap 450 may be used. With only one front strap 450, the front strap 450 may wrap laterally over the top of the foot 100 and adhere to the bottom surface of the foot sole support 410 on the opposite side of the foot 100. In another alternative embodiment, only one front strap 450 may be used and the front strap 450 may be separate and distinct from the foot sole support 410. With the foot sole support 410 already installed on the bottom of the foot 100, the front strap 450 may then be adhered to the foot sole support 410 on one side of the foot 100. The front strap 450 may then be wrapped laterally over the foot 100, down the opposite side of the foot 100, and adhered to the foot sole support 410 on the opposite side of the foot 100. During the course of walking, the foot sole support 410 may be subjected to lateral and longitudinal forces from contact between the foot sole support 410 and other surfaces such as the interior of shoes or floor surfaces. Depending on the level of the lateral and longitudinal forces, the resistance to lateral and longitudinal forces provided by the adhesive layer 411 may be exceeded. Adhering the front straps 450 near the ball of the foot 100 provides extra resistance to lateral and longitudinal forces that may otherwise cause the foot sole support 410 to shift around on the bottom of the foot. Installation of the front straps 450 also reduces stress on the plantar fascia. As shown in FIG. 1, portions of the plantar fascia attach to the ball of the foot and other portions such as the superficial tracts 130 continue past the ball of the foot 100 to the toe region. Due to the complex structure of tissue and bones in the human foot, tissues near the ball of the foot interact with other tissues in the foot to transfer forces induced during walking. Through the attachments near the ball of the foot, tissues near the ball of the foot transfer forces to and from the plantar fascia 110. Providing extra support near the ball of the foot 100 reduces the amount of stress transferred between the ball of the foot and the plantar fascia 110. The stretch resistant plantar fascia support system 400 includes a toe strap 440. Installation of the toe strap 440 assists in maintaining the position of the foot sole support 410. To install the toe strap 440, the removable protective cover 416 adhered to the inner surface of the toe strap 440 is removed. The toe strap 440 is then pressed against the underside of the toe and the adhesive layer secures the toe strap 440 in place. To further secure the toe strap 440 in place, the toe strap 440 includes a toe strap tab 442. To install the toe strap tab 442, the removable protective cover 416 adhered to the inner surface of the toe strap tab 442 is removed. The toe strap tab 442 is then wrapped up and over the top of the toe of the foot 100. The toe strap is wrapped back down the opposite side of the toe and adhered to the underside of toe strap 440 on the opposite side of the toe. In the alternative, more than one toe strap tab 442 may be attached to the toe strap 440. For example, a second toe strap tab may be positioned opposite the toe strap tab shown in FIG. 3 on the opposite side of the toe strap 440. To install the toe strap tabs 442, the removable protective cover 416 adhered to the inner surface of the toe strap tabs 442 is removed. The toe strap tabs 442 are then wrapped up and over the top of the toe. To secure the toe strap tabs 442 in place, one of the toe strap tabs 442 may overlap the other toe strap tab 442 and be adhered to the outer surface of the other toe strap tab 442 similar to the arch straps 420 shown in FIG. 3. In another alternative embodiment, only one toe strap tab 442 may be used and the toe strap tab 442 may be separate and distinct from the toe strap 440 and the foot sole support 410. With the toe strap 440 already installed on the bottom of the toe, the toe strap tab 442 may then be adhered to the toe strap 440 on one side of the toe. The toe strap tab 442 may then be wrapped laterally over the toe, down the opposite side of the toe, and adhered to the toe strap 440 on the opposite side of the toe. The stretch resistant plantar fascia support system 410 may also include indicia 415 printed on the removable protective covers 416. The indicia 415 may represent instructions for the installation of the stretch resistant plantar fascia support system 410. For example, the indicia 415 may be numerical or alphabetic designations for the order in which portions of the stretch resistant plantar fascia support system 410 are to be installed. In FIG. 3, the indicia 415 on the removable protective cover 416 over the foot sole support 410 is the number “1” designating that the foot sole support 410 is to be installed first. The indicia 415 on the removable protective cover 416 on the arch straps 420 is the number “2” designating that the arch straps 420 are the next portion to be installed. Thus, the indicia may be increased or decreased incrementally to designate the order in which the portions of the stretch resistant plantar fascia support system 400 are to be installed. In the alternative, letters or words may be used instead of numerals as the indicia 415 to designate the order in which the portions of the stretch resistant plantar fascia support system 400 are to be installed. For examples, letters “A”, “B”, and “C” or the words “First”, “Second”, and “Third” may be used to designate the order in which the first three portions are to be installed. In the alternative, the indicia 415 may be printed on the various portions of the stretch resistant plantar fascia support system 400. For example, if an adhesive spray is applied to the skin rather than using an adhesive layer 411 and removable protective covers 416, the indicia 415 may be printed on the inner surface of components such as the foot sole support 410 and a consumer may still be able to see the indicia and determine the order of application. In an alternative embodiment, the stretch resistant plantar fascia support system 400 may include the foot sole support 410 without the arch straps 420, the heel strap 430, the toe strap 440, and front strap 450 and the heel tabs 460. Similar to the embodiment shown in FIG. 3, the foot sole support 410 would be adhesively applied to the bottom surface of the foot. In the alternative, the stretch resistant plantar fascia support system 400 may include various combinations of the arch straps 420, the heel strap 430, the toe strap 440, and front straps 450 and the heel tabs 460. For example, an alternative embodiment of the stretch resistant plantar fascia support system 400 may include the foot sole support 410 with arch straps 420. Another alternative embodiment of the stretch resistant plantar fascia support system 400 may include the foot sole support 410 with the heel strap 430. Yet another alternative embodiment of the stretch resistant plantar fascia support system 400 may include the foot sole support 410 with the toe strap 440. Consequently, various alternative embodiments of the stretch resistant plantar fascia support system 400 may be used that include the foot sole support 410 with different combinations of the arch straps 420, the heel strap 430, the toe strap 440, and front strap 450 and the heel tabs 460. FIG. 4 illustrates a stretch resistant plantar fascia support system 500 as an alternative embodiment of the stretch resistant plantar fascia support system 400 of FIG. 3 installed on a human foot. The alternative embodiment shown in FIG. 4 includes a foot sole support 410, arch straps 420, heel strap 430, heel strap tabs 432, toe strap 440, and toe strap tab 442. As shown in FIG. 4, the foot sole support 410 may be adhered to the sole of the foot to provide additional support to the region underneath the plantar fascia. The arch straps 420 may be wrapped around the top of the foot to provide additional support near the arch. The heel strap 430 may be adhered to the back of the heel to provide additional support to the heel and stabilize the position of the foot sole support 410. The toe strap 440 may be adhered to the bottom of the toe and the toe strap 442 wrapped around the toe to provide additional support to the toe and stabilize the position of the foot sole support 410. FIG. 5 illustrates stresses in the human foot 100 shown in FIG. 2 with a stretch resistant plantar fascia support system 400 attached to the human foot 100 in accordance with an embodiment of the present invention. As described previously with regard to FIG. 2, the stress line 300 shows an approximation of the line of forces transferred through a foot 100 during typical motion. The stress line 300 resembles the shape of an archer's bow. The plantar fascia 110 running along near the bottom surface of the foot 100 is analogous to a string in the archer's bow. Forces that tend to move the ends of the bow apart increase tension on the string. In other words, as forces on the arch push the bones downward, the plantar fascia 110 is subjected to tensile forces. To reduce the tensile forces on the plantar fascia 110, the stretch resistant plantar fascia support system 400 is attached to the bottom of the foot. As depicted in FIG. 5, the stretch resistant plantar fascia support system 400 is analogous to another string in the archer's bow connected in parallel with the plantar fascia 110. Tensile forces induced in the bottom of the foot are shared between the plantar fascia 110 and the stretch resistant plantar fascia support system 400. Consequently, tensile force in the plantar fascia 110 is reduced and damaged areas may heal with a reduced likelihood of being subjected to excessive tensile forces. Thus, a stretch resistant plantar fascia support system using a substantially stretch resistant material may be conveniently and easily applied to the foot of a patient by the patient for the treatment of plantar fasciitis. For example, the entire foot sole support, or portions of the foot sole support, of the stretch resistant plantar fascia support system may be made of a flexible material that exhibits less than 15 percent elongation when subjected to a 251b tensile load under test conditions specified in ASTM D3759. In addition, a material with a ratio of elongation to tensile strength (lb/in-width) that is less than 0.9 may be used to provide a balanced combination of strength and resistance to elongation. Additionally, to simplify manufacturing and reduce cost, the stretch resistant plantar fascia support system may be made of a uniform material supplied in sheet form. Portions of the stretch resistant plantar fascia support system may be cut or punched from sheets of material. For example, the foot sole support may be shaped to resemble the outline of the sole of a left or right foot. Alternatively, the foot sole support may also be shaped for interchangeable use on either a left or right foot. The stretch resistant plantar fascia support system may then be packaged individually, in multiples, or in a continuous package such as a roll with individual patches separated by perforations. For example, the individual packaging could be used by the average consumer for everyday use around the home. The continuous packaging could be used in high use situations such as locker rooms where access to stretch resistant plantar fascia support systems is required by multiple people. The stretch resistant plantar fascia support system may be used while sleeping, while walking around with barefeet, or while wearing various types of footwear. Also, the stretch resistant plantar fascia support system non-invasively reduces the level of tensile stress carried by the plantar fascia and may prevent the need for complex and expensive surgery. For example, a consumer may wake-up in the morning and experience pain along the bottom of the consumer's foot. The consumer may recognize the pain as plantar fasciitis and desire to treat the pain. Rather than schedule an appointment with a doctor and have to travel to the doctor's office for treatment, during which time the plantar fascia may be subjected to further excessive tensile stress, the consumer may desire to treat the pain at home. With the stretch resistant plantar fascia support system of the present invention, the consumer may save the time, expense, and pain of traveling to a doctor's office for treatment. To use the stretch resistant plantar fascia support system, the consumer would simply remove the removable protective covers that protect the adhesive layer and apply the stretch resistant plantar fascia support system to the affected area. While the above scenario described the consumer applying the stretch resistant plantar fascia support after waking up in the morning, the stretch resistant plantar fascia support system may also be worn to bed at night. By wearing the stretch resistant plantar fascia support system to bed at night, the stretch resistant plantar fascia support system may aid in the healing process while the consumer sleeps and protects the plantar fascia during the first few steps in the morning when stress is re-applied. In addition, the stretch resistant plantar fascia support system may be comfortably worn when the consumer is not currently experiencing pain, but anticipates the potential for injury during a strenuous activity. For example, a consumer with a history of frequent occurrences of plantar fasciitis may desire to return to a strict exercise regiment following a prolonged period of inactivity. To avoid overstressing the plantar fascia until the foot has had enough time to become re-accustomed to the stresses of exercise, the consumer may desire to use the easily applied stretch resistant plantar fascia support system rather than some of the more cumbersome, less effective, and inconvenient alternatives such as taping and molded arch supports. To aid the consumer with installation of the stretch resistant plantar fascia support system, the removable protective covers, or other portions of the stretch resistant plantar fascia support system, may include numerical indicia that indicate the order in which portions of the stretch resistant plantar fascia support system are applied to the foot. The consumer then applies the stretch resistant plantar fascia support system to the consumer's foot in the prescribed order. In addition, the stretch resistant plantar fascia support system is comfortable and form fitting. The stretch resistant plantar fascia support system may be supplied for a plurality of foot sizes and the consumer may select the stretch resistant plantar fascia support system much like shoes are selected based upon standard shoe sizes. The foot sole support of the stretch resistant plantar fascia support system may even be shaped to conform to the shape of the sole of a foot. If an adjustment is needed to adapt the stretch resistant plantar fascia support system to an irregularity in a particular consumer's foot, the stretch resistant plantar fascia support system may be easily adapted by cutting the stretch resistant plantar fascia support system to accomodate the irregularity. Because the stretch resistant plantar fascia support system is form fitting, the consumer may wear the stretch resistant plantar fascia support system in a variety of situations. For example, if a woven rayon microfiber with a 3600 thread count and/or thickness less than 30 mils is used, then the stretch resistant plantar fascia support system is thin enough to comply with contours of the foot and strong enough to provide adequate strength. While the consumer has the stretch resistant plantar fascia support system attached to the consumer's foot, the consumer has the option of walking around in bare feet, pulling a sock over the foot, or putting on shoes. The consumer may also wear the stretch resistant plantar fascia support system while using other additional devices such as arch supports, night splints, and custom orthotics. Also, the stretch resistant plantar fascia support system does not interfere with rotation and movement of the ankle or calves. The stretch resistant plantar fascia support system is positioned beneath the ankle. The heel straps and the heel strap tabs are sized to avoid interference with the ankle bone. Because the stretch resistant plantar fascia support system is positioned beneath the ankle, contact between adhesive and leg hair is reduced. Thus, the need for shaving portions of the leg and ankle is reduced. Also, different embodiments of the stretch resistant plantar fascia support system may be used depending on the type of footwear the consumer desires to wear while the stretch resistant plantar fascia support system is attached. For example, if the consumer is going to wear sandals, the consumer may desire to use a stretch resistant plantar fascia support system with a foot sole support and no adhesive straps or tabs to reduce the visibility of the stretch resistant plantar fascia support system. On the other hand, the consumer may desire to wear boots, where visibility of the stretch resistant plantar fascia support system is not an issue, and the consumer desires to have straps and tabs along with the foot sole portion for added stability. The present invention may also include other items that can benefit a user. For example, to minimize the potential for skin damage and foot odor from the presence of moisture, the stretch resistant plantar fascia support system may be made of a permeable material. The stretch resistant plantar fascia support system may be made of a permeable material that wicks moisture away from the skin or the stretch resistant plantar fascia support system may include holes in the material to allow for the evaporation of moisture. In conjunction with the permeable material, adhesive may be applied in an intermittent manner to further increase the permeability and reduce the presence of moisture trapped between the foot and the stretch resistant plantar fascia support system. Also, the stretch resistant plantar fascia support system may include additives such as medicines, anti-fungal treatments, anti-microbial treatments, anti-inflammatory treatments, cooling compounds, heating compounds, deodorants, zeolite, perfumes, moisturizers, tee tree oil, talcum powder, and zinc oxide. Thus, the present invention provides an effective system for the treatment of plantar fasciitis that is both economical and easy to use. The present invention provides a stretch resistant system that may be discretely attached to a patient's foot and reduces stress on the plantar fascia. While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>The present invention generally relates to a stretch resistant plantar fascia support system. More particularly, the present invention relates to a stretch resistant plantar fascia support system that may be adhesively applied to a foot to provide relief from plantar fasciitis. FIG. 1 is a dissected bottom view of a human foot 100 provided to illustrate some of the parts of a plantar fascia 110 located in the bottom of the human foot 100 . As shown in FIG. 1 , the plantar fascia 110 extends from about the location of the heel 101 to about the location of the ball 102 of the foot. The plantar fascia 110 includes medial plantar fascia 120 , superficial tracts 130 , a central component of the plantar fascia 140 , and a lateral component of the plantar fascia 150 . The separate portions of the plantar fascia 110 act as a shock absorber while walking and transfer tensile forces along the bottom of the foot 100 . FIG. 2 illustrates a simplified side view of tissue and bone structure in the human foot 100 . As shown in FIG. 2 , the human foot 100 includes the plantar fascia 110 , a plantar calcaneus 160 , a talus 162 , a navicular 164 , a cuneiform 166 , a cuboid 168 , metatarsals 170 , phalanges 172 , a sesamoid 174 , a fat pad area 176 , and an outer skin surface 178 . From the side view in FIG. 2 , the plantar calcaneus 160 , the talus 162 , the navicular 164 , the cuneiform 166 , the cuboid 168 , the metatarsals 170 , and the sesamoid 174 form what resembles the shape of an arch. This shape is commonly referred to as the longitudinal arch. Another arch commonly referred to as the transverse arch (metatarsal) also exists in about the same area in a perpendicular direction that runs laterally across the width of the foot. The plantar fascia 110 serves the vital role of maintaining the shape of the two anatomical arches of the foot, the transverse arch and the longitudinal arch. As illustrated in FIGS. 1 and 2 , the plantar fascia 110 runs across the bottom of the foot 100 from the heel 101 to the ball 102 and spreads out across the width of the foot 100 . As longitudinal and lateral tensile stresses are produced in the bottom of the foot 100 , the plantar fascia 110 absorbs the tensile forces and maintains the shape of the two anatomical arches. For example, while standing or while in motion, forces experienced by the foot 100 act in a direction which tends to flatten the arches. The stress line 300 in FIG. 2 shows an approximation of the line of forces transferred through foot 100 during typical motion. As shown in FIG. 2 , the stress line 300 resembles the shape of an archer's bow. The plantar fascia 110 running along near the bottom surface of the foot 100 is analogous to a string in the archer's bow. Forces that tend to move the ends of the bow apart increase tension on the string. In other words, as forces on the arch push the bones downward, the plantar fascia 110 is subjected to tensile forces. If the tension on the plantar fascia 110 becomes excessive, the plantar fascia 110 may be damaged and produce a condition called plantar fasciitis. Plantar fasciitis is a painful medical condition resulting from inflammation of the plantar fascia 110 . The plantar fascia 110 is thick and essentially inelastic. Overstressing the plantar fascia 110 may produce tears in the plantar fascia 110 or separate the plantar fascia 110 from bone and other surrounding materials. Tearing and separation of the plantar fascia 110 produces the painful inflammation known as plantar fasciitis. Frequently, the inflamed areas 305 are along the arch of the foot 100 or near the heel 101 of the foot 100 as shown in FIG. 2 . Plantar fasciitis may be quite debilitating in that everyday activities such as walking and standing may be very painful. Typical treatments for plantar fasciitis may involve oral anti-inflammatories, ice packs, bedrest, stretching, steroid injections, night splints and wedge-shaped arch supports. In extreme cases, treatment of plantar fasciitis may require corrective surgery. For example, a design for an orthotic device for treatment of plantar fasciitis is disclosed in Gleason, U.S. Pat. No. 5,865,779. The device of Gleason is an elastic sock that is worn on a patient's foot. The elastic sock exerts compressive forces along the longitudinal and transverse axes of the patient's foot. While some patients may be willing to wear an elastic sock, the elastic sock is both inconvenient and cumbersome. In order to be installed on the foot, the elastic sock must be stretched to fit over the heel and toe of the foot. Because the sock is elastic, the sock allows the foot to move and stretch. Consequently, the plantar fascia may still be subjected to excessive tensile forces during the critical heeling process. Re-subjecting the plantar fascia to tensile forces before it has completely healed may re-aggravate damaged portions of the plantar fascia and undermine the healing process. In addition, the elastic sock is meant to be worn multiple times and may require regular cleaning to avoid odors and foot infections. Also, the sock may not fit inside a shoe while being worn and may be considered unsightly while walking around with bare feet. Consequently, the elastic sock does not prevent excessive stretching of the plantar fascia and is both inconvenient and cumbersome. Another typical example of treatment for plantar fasciitis includes medical personnel strapping strips of tape to the bottom of an injured foot. Strips of tape are applied at various angles across the bottom of the foot. The tape is difficult to remove from the rolls and bunches up during the taping process. Thus, care must be exercised during the application of the tape to avoid blister-causing wrinkles in the tape and other problems. As the patient walks with the taped foot, the tape works loose and stretches with time. In addition, the tape cannot be effectively applied by the patient to the patient's own foot and requires application by another individual such as a trained medical technician. Consequently, taping the foot is cumbersome, inefficient, and ineffective in preventing excessive stretching of the plantar fascia. Sometimes when current methods of treatment for plantar fasciitis are ineffective, expensive surgical procedures are required to relieve the pain of plantar fasciitis. To get at the plantar fascia, surgeons may perform either an endoscopic procedure requiring small incisions or conventional direct visualization requiring the underside of the foot to be opened up. With either painful procedure, scars may result and recovery time may be from weeks to months. Even with treatment, improper treatment of plantar fasciitis may lead to other medical problems. For example, if inflammation near the heel is allowed to continue for a long period of time, calcium deposits may build-up in the damaged region. As the calcium builds-up, bony outcroppings may develop in the heel that are commonly referred to as “heel spurs”. The longer the plantar fascia remains inflamed around the heel, the stronger the conditions are for the development of heel spurs. Protrusion of the heel spurs into the surrounding tissue may result in a cycle of irritation, inflammation, and pain known as heel spur syndrome. Heel spur syndrome is commonly treated with a surgical procedure requiring removal of the heel spurs from within the foot. An endoscopic procedure is typically not used for removal of heel spurs and open surgery is typically required. Recovery time from such surgery may range from weeks to months, during which time the patient has to curtail the amount of stress placed on the foot. Thus, it may be highly desirable to have a system for avoiding and/or treating the pain of plantar fasciitis. It may also be highly desirable to have a system for treating plantar fasciitis that is economical and may be easily applied by the patient. It may also be highly desirable to have a system for treating plantar fasciitis that is discretely attached to the sole of the patient's foot and includes a substantially stretch resistant material to reduce tensile forces in the plantar fascia. | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>A preferred embodiment of the present invention provides a system for treatment of plantar fasciitis. The system is economical and may be easily applied by a patient. A stretch resistant plantar fascia support system is provided with a foot sole support. The foot sole support may be a thin one-piece device made of a uniform substantially stretch resistant material of a uniform thickness or the foot sole support may be made with a strip of substantially stretch resistant material bounded by a more deformable material. The foot sole support may be shaped to conform to the outline of the bottom of a foot or shaped to cover only a portion of the bottom of a foot. Straps and tabs may be included with the foot sole support for providing additional support to both the foot and other portions of the stretch resistant plantar fascia support system. The foot sole support, straps, and tabs have adhesive applied to portions of the surface of the foot sole support, the straps, and the tabs. Removable protective covers are applied over the adhesive and the removable protective covers may include indicia signifying the order in which the portions of the stretch resistant plantar fascia support system are to be applied to the foot. To relieve the symptoms of plantar fasciitis, tensile stresses in the plantar fascia are reduced. The tensile stresses in the plantar fascia are reduced by adhering the foot sole support to the foot of the patient. The foot sole support absorbs tensile stress in the lower foot thereby reducing the tensile stress experienced by the plantar fascia and surrounding tissues. The straps and tabs may be attached in the prescribed order to the foot sole support and wrapped around or attached to portions of the foot to provide additional support to the stretch resistant plantar fascia support system. | 20040402 | 20130409 | 20051013 | 62580.0 | 3 | PATEL, TARLA R | System for treatment of plantar fasciitis | SMALL | 0 | ACCEPTED | 2,004 |
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10,817,178 | ACCEPTED | Method for controlling the temperature of a baking oven having a catalyst | A method for controlling the temperature of a baking oven having a catalyst, a heating source, an oven chamber temperature sensor, and a catalyst temperature sensor, includes generating an electrical control signal based on a control state, the control state being a function of signals from the electrical sensors and being reached when the catalyst temperature is higher than the oven chamber temperature and the temperature difference between the catalyst temperature and the oven chamber temperature is greater than or equal to a threshold value. The heating source is controlled using the electrical control signal so that the oven chamber temperature is maintained substantially constant. | 1-8. (canceled) 9. A method for controlling the temperature of a baking oven including a catalyst, a heating source, an oven chamber temperature sensor, and a catalyst temperature sensor, the method comprising: generating a first electrical control signal based on a first control state, the first control state being a function of respective electrical sensor signals from the oven chamber temperature sensor and the catalyst temperature sensor, the first control state being reached when a catalyst temperature is higher than an oven chamber temperature and a temperature difference between the catalyst temperature and the oven chamber temperature is greater than or equal to a first threshold value; and controlling the heating source using the first electrical control signal so that the oven chamber temperature is maintained substantially constant. 10. The method as recited in claim 9 wherein the heating source includes an electrical heating element of the baking oven. 11. The method as recited in claim 9 further comprising generating a second electrical control signal based on a second control state, the second control state being a function of the electrical sensor signals and being reached when the catalyst temperature is higher than the oven chamber temperature, and the temperature difference between the catalyst temperature and the oven chamber temperature is smaller than a second threshold value and was previously greater than the first threshold value. 12. The method as recited in claim 11 further comprising controlling the heating source using the second electrical control signal so that the oven chamber temperature is increased or maintained substantially constant at a first predefined value for a first predetermined period of time. 13. The method as recited in claim 9 further comprising generating a third electrical control signal based on a third control state, the third control state being a function of the electrical sensor signals and being reached when the catalyst temperature is higher than the oven chamber temperature and the temperature difference between the catalyst temperature and the oven chamber temperature is greater than or equal to a third threshold value. 14. The method as recited in claim 13 further comprising controlling the heating source using the third electrical control signal so that the oven chamber temperature falls to or below a fourth threshold value. 15. The method as recited in claim 14 further comprising generating a fourth electrical control signal based on a fourth control state, the fourth control state being a function of the electrical sensor signals and being reached when the catalyst temperature is higher than the oven chamber temperature, the oven chamber temperature is at the fourth threshold value, and the temperature difference between the catalyst temperature and the oven chamber temperature was previously greater than or equal to the third threshold value. 16. The method as recited in claim 15 further comprising controlling the heating source using the fourth electrical control signal so that the oven chamber temperature is maintained substantially constant at the fourth threshold value. 17. The method as recited in claim 9 further comprising controlling the heating source using the first electrical control signal so that the oven chamber temperature is maintained substantially constant at a second predefined value for at least a second predetermined period of time. 18. The method as recited in claim 13 further comprising controlling the heating source using the third electrical control signal so that the oven chamber temperature is maintained substantially constant at a second predefined value for at least a second predetermined period of time. 19. The method as recited in claim 9 wherein the baking oven includes a control unit having an evaluation circuit configured to process the electrical sensor signals, and wherein the generating is performed by the control unit. | The present invention relates to a method of the type mentioned in the preamble of claim 1 for controlling the temperature of a baking oven containing a catalyst. A method of this type is known, for example, from German Patent DE 197 06 186. In this method, the oven chamber temperature and the catalyst temperature can be controlled separately because the catalyst has a separate catalyst heater. Temperature-time profiles, or threshold values, which are dependent on the selected operating mode, for example, the pyrolytic mode, are stored in the control unit for the oven chamber temperature and the catalyst temperature. If the pyrolysis temperature is not reached within a predetermined time, then the oven chamber heater is turned off for safety reasons. If threshold values for the catalyst temperature, which are also predefined, should be exceeded during pyrolysis, then the oven chamber heater, or the catalyst heater, is turned off as well. Furthermore, German Patent Application DE 196 06 571 A1 describes a temperature control method in which a pyrolytic cleaning process is controlled as a function of the oven chamber temperature and of a soil sensor that detects the catalyst temperature. In this method, in a first phase of the cleaning process, the oven chamber is heated to about 300° C. only as a function of the oven chamber temperature. In a subsequent second phase of the cleaning process, the oven chamber is then further heated to a maximum temperature required for the pyrolytic cleaning process only as a function of the catalyst temperature. Moreover, U.S. Pat. No. 4,292,501 describes a temperature control method in which during a pyrolytic cleaning process, the oven chamber is heated only as a function of the catalyst temperature. Once the catalyst temperature exceeds a predefined value, the oven chamber heater is turned off, stopping the pyrolytic cleaning process. Another temperature control method is known from U.S. Pat. No. 6,232,584 B1. In this method, the pyrolysis time is controlled as a function of the oven chamber temperature and the catalyst temperature. Once the catalyst temperature, after it has first exceeded the oven chamber temperature, falls below this temperature, the pyrolytic cleaning process is terminated after a predetermined period of time has elapsed. Furthermore, European Patent Application EP 0 878 667 A2 describes a method in which the pyrolytic cleaning process is terminated when the temperature difference between the catalyst temperature and the oven chamber temperature falls below a predefined value. It is therefore an object of the present invention to provide a simple method for controlling the temperature of a baking oven containing a catalyst, in which method unwanted coating of the catalyst surface with unconverted vapor components is reduced even when the oven chamber is heavily soiled. This objective is achieved according to the present invention by a method for controlling the temperature of a baking oven containing a catalyst having the features of Patent claim 1. Advantageous embodiments and refinements of the present invention will become apparent from the following dependent claims. In addition to a simple method for controlling the temperature of a baking oven containing a catalyst, a particular advantage that can be achieved with the present invention is a system for implementing the method that is simple in design and therefore inexpensive. In an advantageous refinement, it is proposed to generate a second electrical control signal based on a second control state; the second control state being reached when the catalyst temperature is higher than the oven chamber temperature, and the temperature difference between the catalyst temperature and the oven chamber temperature is initially greater than the first threshold value and, at a later time, is smaller than a second threshold value. Thus, the inertia of the system to be controlled can be compensated for in the control. The influence of the second electrical control signal on the heating source can, in principle, be selected within wide suitable limits. Advantageously, the second electrical control signal acts on the heating source in such a manner that the oven chamber temperature is increased or maintained substantially constant at a first predefined value for a first predetermined period of time. In a particular advantageous refinement of the teaching of the present invention, it is proposed to generate a third electrical control signal based on a third control state; the third control state being reached when the catalyst temperature is higher than the oven chamber temperature and the temperature difference between the catalyst temperature and the oven chamber temperature is greater than or equal to a third threshold value. In this manner, the control system according to the present invention is further refined so that the oven chamber temperature follows a predetermined pattern even better in its profile over time. An advantageous further development of the aforementioned embodiment proposes that the third electrical control signal act on the heating source in such a manner that the oven chamber temperature falls to or below a fourth threshold value. This allows quick control so that the desired temperatures can be reached with little delay. In a further advantageous refinement, it is proposed to generate a fourth electrical control signal based on a fourth control state; the fourth control state being reached when the catalyst temperature is higher than the oven chamber temperature, the temperature difference between the catalyst temperature and the oven chamber temperature is initially greater than or equal to the third threshold value, and, at a later time, the oven chamber temperature is at the fourth threshold value. This further improves the compensation of the inertia of the system to be controlled. A particularly advantageous refinement of the aforementioned embodiment proposes that the fourth electrical control signal act on the heating source in such a manner that the oven chamber temperature is maintained substantially constant at the fourth threshold value. This allows transient response of the control system in spite of improved inertia compensation. In an advantageous refinement of the teaching according to the present invention, it is proposed that the first and/or the third electrical control signal(s) act on the heating source in such a manner that the oven chamber temperature is maintained substantially constant at a second predefined value for at least a second predetermined period of time. Thus, for example, in the pyrolytic mode, it is possible to adapt the pyrolysis time to the soil level of the baking oven. An exemplary embodiment of the present invention is shown in the drawings in a purely schematic way and will be described in more detail below. In the drawing, FIG. 1 is a partial perspective view of a system for implementing the method according to the present invention; FIG. 2 is a temperature-time diagram of a first exemplary sequence of the method according to the present invention; FIG. 3 is a temperature-time diagram of a second exemplary sequence of the method according to the present invention; and FIG. 4 is a temperature-time diagram of a third exemplary sequence of the method according to the present invention. In FIG. 1, system for implementing the method according to the present invention is shown by way of example. This system is system is a baking oven (2) containing a catalyst (4) located in the exhaust path for the vapors. To heat oven chamber (6) of baking oven (2), a heating source (8) in the form of an electric radiant heating element is disposed in oven chamber (6). The heating power of heating source (8) is controllable via a control unit (10). For this purpose, an oven chamber temperature sensor (12) in the form of an electrical resistance temperature sensor is disposed in oven chamber (6), and a catalyst temperature sensor (14), which also takes the form of an electrical resistance temperature sensor, is arranged downstream of catalyst (4) in the direction of flow. Oven chamber temperature sensor (12), catalyst temperature sensor (14), and heating source (8) are electrically conductively connected to control unit (10), allowing electrical signals to be exchanged between temperature sensors (12, 14) and control unit (10). Moreover, heating source (8) is supplied with an electrical heating current as a function of an electrical signal of control unit (10). In this exemplary embodiment, control unit (10) has a microprocessor and a memory (not shown). In the memory, data is stored for the different operating modes of the baking oven, such as the pyrolytic mode. The electrical sensor signals of oven chamber temperature sensor (12) and catalyst temperature sensor (14) are processed in an evaluation circuit (also not shown) of control unit (10) in such a manner that when a control state which is dependent on the electrical sensor signals is reached, control unit (10) generates at least one electrical control signal that influences heating source (8) in a predetermined manner. For example, during the pyrolytic cycle, control unit (10) compares the current electrical sensor signals to the data stored in the memory. In control unit (10) of this exemplary embodiment of the present invention, the current temperature difference between the oven chamber temperature and the catalyst temperature is compared to the stored data. If correspondence is established, a control state is reached which in turn produces an electrical control signal that influences the heating current supply to heating source (8). A resulting change in the heating power of heating source (8), in turn, results in a change in the temperature difference between the oven chamber temperature and the catalyst temperature. Moreover, the processing in the evaluation circuit of the control unit depends on whether the catalyst temperature is higher or lower than the oven chamber temperature. The above exemplary embodiment of the method according to the present invention will be explained below with reference to FIGS. 2 through 4: In FIG. 2, the profiles of the oven chamber temperature and the catalyst temperature during the pyrolytic cycle are exemplarily shown in a temperature-time diagram for the case that the oven chamber is only lightly soiled. In the case of light soling of the oven chamber, only a small amount of smoke is produced so that the catalyst performance is not significantly impaired. In the example chosen, the catalyst temperature remains below the oven chamber temperature during the entire time interval shown in the diagram. In this case, initially, the oven chamber temperature is continuously raised to about 320° C. At about 320° C., the oven chamber temperature is maintained substantially constant for about 10 min. After this first holding phase (a), the oven chamber temperature is further increased. At about 460° C., the oven chamber temperature is maintained substantially constant for about 50 min. After this second holding phase (b), the oven chamber temperature is continuously decreased. As can be inferred from FIG. 2, the catalyst temperature follows the profile of the oven chamber temperature over time. In FIG. 3, the profiles of the oven chamber temperature and the catalyst temperature during the pyrolytic cycle are exemplarily shown in a temperature-time diagram for the case that the oven chamber is soiled to a medium degree. If in this case the procedure were analogous to the case of an oven chamber with only a light soil level, which has been explained, by way of example, with reference to FIG. 2, then catalyst (8) would not be able to completely convert the smoke produced by the soil of the oven chamber. The reactive surface of catalyst (8) would become coated with the unconverted vapor components, decreasing the performance of the catalyst. In the case of a medium soil level of the oven chamber, the catalyst performance would therefore be impaired. In order to prevent this, the exemplary embodiment includes the following steps: A first electrical control signal is generated based on a first control state; the first control state being reached when the catalyst temperature is higher than the oven chamber temperature, and the temperature difference between the catalyst temperature and the oven chamber temperature is greater than a first threshold value (c) of 20 K. A second electrical control signal is generated based on a second control state; the second control state being reached when the catalyst temperature is higher than the oven chamber temperature, and the temperature difference between the catalyst temperature and the oven chamber temperature is initially greater than the first threshold value (c) of 20 K, and, at a later time, is smaller than a second threshold value (d) of 15 K. The two method steps will be explained below with reference to FIG. 3: Analogously to the first case, the oven chamber temperature is continuously raised to about 320° C. in the pyrolytic mode, and this oven chamber temperature is maintained for about 10 min. At the end of this first holding phase (a), heating is continued. During this heating, the catalyst temperature increases faster than the oven chamber temperature, and the temperature difference between the catalyst temperature and the oven chamber temperature exceeds the first threshold value (c) of 20 K. The first control state is reached, and the first electrical control signal is generated. Based on this control signal, the electrical heating current to heating source (8) is maintained approximately constant so that the heating power, and thus the oven chamber temperature, are maintained substantially constant (see FIG. 3). As can also be inferred from FIG. 3, the oven chamber temperature is maintained constant until the second control state is reached, i.e., until the temperature difference between the catalyst temperature and the oven chamber temperature has fallen to the second threshold value (d) of 15 K. When the second control state is reached, the second electrical control signal is generated. Based on this control signal, the electrical heating current to heating source (8) is further increased so that the oven chamber temperature increases again. In the case that the first control state is reached during the first holding phase (a), the second electrical control signal initially causes a further 10-minute holding phase (not shown) and, at a later time, causes the oven chamber temperature to further increase. The subsequent profiles of the catalyst temperature and the oven chamber temperature are similar to the first case; however, in addition to the effect mentioned above, the first electrical control signal lengthens the duration of second holding phase (b) by about 10 min. to a total of 60 min. In FIG. 4, the profiles of the oven chamber temperature and the catalyst temperature during the pyrolytic cycle are exemplarily shown in a temperature-time diagram for the case that the oven chamber is heavily soiled. In comparison with the aforementioned example case, the catalyst would convert even less smoke, and the catalyst performance would be impaired to an even greater extent. In order to prevent this, the exemplary embodiment includes the following steps: A third electrical control signal is generated based on a third control state; the third control state being reached when the catalyst temperature is higher than the oven chamber temperature, and the temperature difference between the catalyst temperature and the oven chamber temperature is greater than or equal to a third threshold value (e) of 100 K. A fourth electrical control signal is generated based on a fourth control state; the fourth control state being reached when the catalyst temperature is higher than the oven chamber temperature, the temperature difference between the catalyst temperature and the oven chamber temperature is initially greater than the third threshold value (e) of 100 K, and, at a later time, the oven chamber temperature is at the fourth threshold value (f) of 270° C. The two method steps will be explained below with reference to FIG. 4: Analogously to the two preceding example cases of FIGS. 2 and 3, the oven chamber is initially heated to 320° C., and this oven chamber temperature is maintained substantially constant during first holding phase (a) of about 10 minutes. As the oven chamber is further heated, the catalyst temperature exceeds the oven chamber temperature by more than 20 K, first threshold value (c) is exceeded, and the first electrical control signal, which has already been explained with reference to FIG. 3, is generated so that the oven chamber temperature is maintained constant at its current value of about 360° C. However, due to the heavy soil level of the oven chamber, this measure is not sufficient to prevent the production of smoke, or to reduce it to a level that can be converted by the catalyst, so that the catalyst temperature is further increased, and the temperature difference between the catalyst temperature and the oven chamber temperature reaches the third threshold value (e) of about 100 K. The third electrical control signal is generated, whereupon heating source (8) is turned off. The oven chamber temperature and the catalyst temperature decrease. Once the oven chamber temperature has dropped to the fourth threshold value (f) of 270° C., the fourth control state is reached, and the fourth electrical control signal is generated. The fourth electrical control signal causes the oven chamber temperature to be maintained substantially constant at about 270° C. as the catalyst temperature decreases further. Once the temperature difference between the catalyst temperature and the oven chamber temperature has decreased to the second threshold (d) of 15 K, then, as already explained above, the second electrical control signal is generated so that the oven chamber is heated further. The subsequent profiles of the catalyst temperature and the oven chamber temperature are similar to the two aforementioned example cases; however, the third electrical control signal further causes the duration of the second holding phase (b) at about 460° C. to be lengthened by an additional 10 minutes to a total of then 70 minutes. | 20040402 | 20060822 | 20051027 | 60499.0 | 0 | HOANG, TU BA | METHOD FOR CONTROLLING THE TEMPERATURE OF A BAKING OVEN HAVING A CATALYST | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,817,305 | ACCEPTED | Report format editor for circuit test | A graphical user interface (GUI) of a report format editor for circuit test displays a number of user-selectable representations of circuit test data. The GUI also displays a user-modifiable ASCII report format that is formed, at least in part, of placed ones of the user-selectable representations of circuit test data. Program code interprets the relative sizes and placements of elements forming the user-modifiable ASCII report format, and generates an ASCII format description file in response to the interpretation. A circuit test system then formats circuit test data in accordance with the ASCII format description file. | 1. A report format editor for circuit test, comprising: computer readable media; and program code, stored on the computer readable media, comprising: program code to display a graphical user interface, the graphical user interface displaying i) a number of user-selectable representations of circuit test data, and ii) a user-modifiable ASCII report format that is formed, at least in part, of placed ones of said user-selectable representations of circuit test data; and program code to i) interpret relative sizes and placements of elements forming said user-modifiable ASCII report format, and ii) generate an ASCII format description file in response to said interpretation. 2. The report format editor of claim 1, further comprising code to read a file of circuit test data types and, in response thereto, build said number of user-selectable representations of circuit test data. 3. The report format editor of claim 1, further comprising code to query a test instrument for circuit test data types and, in response to results from said query, build said number of user-selectable representations of circuit test data. 4. The report format editor of claim 1, wherein said user-selectable representations of circuit test data are displayed in a persistently visible portion of the graphical user interface. 5. The report format editor of claim 1, wherein said user-selectable representations of circuit test data are provided via a pull-down menu of the graphical user interface. 6. The report format editor of claim 1, further comprising code that enables a user to drag and drop the user-selectable representations of circuit test data within the ASCII report format. 7. The report format editor of claim 1, further comprising code to associate identifying colors with said placed ones of said user-selectable representations of circuit test data. 8. The report format editor of claim 1, further comprising code to i) associate names with said placed ones of said user-selectable representations of circuit test data, and ii) cause the name of a placed representation of circuit test data to be displayed when a graphical pointer hovers over the placed representation of circuit test data. 9. The report format editor of claim 1, further comprising code that enables said placed representations of circuit test data to be graphically resized within the ASCII report format. 10. The report format editor of claim 1, wherein ones of said placed ones of said user-selectable representations of circuit test data are associated with programmable label fields. 11. The report format editor of claim 1, wherein said programmable label fields comprise a column header field. 12. The report format editor of claim 1, wherein said programmable label fields comprise preamble and postamble fields. 13. The report format editor of claim 1, wherein said graphical user interface further displays a number of user-selectable context fields that may be placed in the ASCII report format. 14. The report format editor of claim 1, further comprising code to read a saved ASCII format description file, conduct a consistency check on the contents thereof, and display a user-modifiable ASCII report format based thereon. 15. The report format editor of claim 1, wherein, upon selection of one of the placed representations of circuit test data, the graphical user interface provides an option to specify a data format for the selected representation. 16. A circuit test system, comprising: computer readable media; and program code, stored on the computer readable media, comprising: code to display a graphical user interface, the graphical user interface displaying i) a number of user-selectable representations of circuit test data, and ii) a user-modifiable ASCII report format that is formed, at least in part, of placed ones of said user-selectable representations of circuit test data; code to i) interpret relative sizes and placements of elements forming said user-modifiable ASCII report format, and ii) generate an ASCII format description file in response to said interpretation; and code to read the ASCII format description file and format circuit test data in accordance therewith. 17. The system of claim 16, further comprising code to read a file of circuit test data types and, in response thereto, build said number of user-selectable representations of circuit test data. 18. The system of claim 16, wherein said code to format circuit test data receives and processes a real-time stream of circuit test data. | BACKGROUND OF THE INVENTION Some circuit test systems output circuit test data in accordance with a fixed report format. Other circuit test systems allow circuit test data to be mapped to arbitrary locations. However, these latter circuit test systems require a user to understand low-level details of the system's output data, as well as a programming language such as “C”. SUMMARY OF THE INVENTION One aspect of the invention is embodied in a report format editor for circuit test. The editor comprises code to display a graphical user interface (GUI). The GUI, in turn, displays 1) a number of user-selectable representations of circuit test data, and 2) a user-modifiable ASCII report format that is formed, at least in part, of placed ones of the user-selectable representations of circuit test data. Program code interprets relative sizes and placements of elements forming the user-modifiable ASCII report format and generates an ASCII format description file in response to the interpretation. Other embodiments of the invention are also disclosed. BRIEF DESCRIPTION OF THE DRAWINGS Illustrative and presently preferred embodiments of the invention are illustrated in the drawings, in which: FIG. 1 illustrates exemplary code portions of a circuit test system; FIG. 2 illustrates exemplary code portions of the report format editor shown in FIG. 1; and FIGS. 3-6 illustrate various graphical user interfaces that might be displayed by the report format editor shown in FIG. 2. DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates an exemplary circuit test system 100 comprising various pieces of program code 102, 104, 106. By way of example, the program code may be stored on various forms or combinations of computer readable media, including any one or more of: fixed disks, removable disks, random access memories (RAMs), read only memories (ROMs), magnetic disks, and optical discs. Further, and by way of example, the program code may be installed on a circuit tester (e.g., the 93000 System on a Chip (SOC) tester, manufactured by Agilent Technologies, Inc. of Palo Alto, Calif., USA), on a computer system (e.g., a personal computer (PC)), or over a network (e.g., with parts of the code being installed on a circuit tester, and with parts of the code being stored on a personal computer). In the upper portion of the system 100 (above the upper hash line), circuit test data flows from left to right and is processed by program code 102 that reads an ASCII format description file 106 and formats the test data in accordance therewith. In one embodiment, the code 102 receives and processes a real-time stream of circuit test data 108 as the data is generated during circuit test. In another embodiment, the code 102 might receive and processes the circuit test data in batches. In yet another embodiment, the code 102 might access and process a stored file of circuit test data. The lower portion of the system (below the lower hash line) comprises a report format editor 104. As shown in FIG. 2, the report format editor 104 comprises code 200 to display a graphical user interface (GUI). As shown in FIG. 3, the GUI 300 displays a number of user-selectable representations of circuit test data 302, 304, 306, 308, 310, as well as a user-modifiable ASCII report format 312 that is formed, at least in part, of placed ones of the user-selectable representations of circuit test data 302a, 308a. In one embodiment, the representations of circuit test data 302-310 comprise names of circuit test data that are displayed in a persistently visible portion of the GUI 300 (e.g., in a persistently visible list of circuit test data names; see FIG. 3). Alternately, the representations of circuit test data 302-310 may be provided via a pull-down menu of the GUI 400 (see FIG. 4). The representations of circuit test data 302-310 may also comprise exemplary depictions (e.g., icons) of the circuit test data, or colors that identify the circuit test data. Regardless of how the representations of circuit test data 302-310 are provided, the report format editor 104 preferably comprises code that enables a user to drag and drop the representations within the ASCII report format 312. Once a representation of circuit test data has been placed within the ASCII report format, it may continue to be represented by its name or icon. However, it is preferably represented by an exemplary data string (e.g., “x,xxx.xx” or “______data______”). As will be described later, placed test data may also be identified by other means. The report format editor 104 (FIG. 2) further comprises program code 202 to 1) interpret relative sizes and placements of elements forming the user-modifiable ASCII report format, and 2) generate the ASCII format description file 204 in response to the interpretation. In this manner, a user (through user input 206) can graphically create and/or manipulate the format of data that is output from the system 100. As shown in FIG. 1, the upper and lower portions of the circuit test system 100 both access the same ASCII format description file 106. In some embodiments, this description file may also be manually edited by means of a simple text editor or other editing software. The report format editor 104 may therefore comprise code to conduct a consistency check on the contents of the description file 106. Preferably, the consistency check is automatically conducted each time the file 104 is read. However, the user could also be given an option to manually trigger the consistency check from within the report format editor 104. The report format editor 104 may also comprise code to build the number of user-selectable representations of circuit test data 302-310 that it displays. In one embodiment, this code reads a file of circuit test data types 110 and, in response thereto, builds the user-selectable representations of circuit test data. In another embodiment, the code queries a test instrument for circuit test data types and, in response to results from the query, builds the user-selectable representations of circuit test data 302-310. In yet another embodiment, a user might manually enter a number of circuit test data items into the report format editor 104. As previously alluded to, the report format editor 104 may employ a variety of mechanisms to assist a user in easily identifying what kinds of circuit test data 302a, 308a are placed in their ASCII report format 312. In one embodiment, the report format editor 104 comprises code to associate identifying colors with the representations of circuit test data 302, 308a appearing in the ASCII report format 312. For example, each of the circuit test data representations 302-310 displayed on the left side of the FIG. 3 GUI 300 may be displayed in a color that is unique to the test data item, or at least unique to its test data type. Placed representations of the circuit test data 302a, 308a then appear in the same color so that the representations 302-310 on the left may be easily referred to for more information about (e.g., the name of) data 302a, 308a that has been placed in the ASCII report format 312. Alternately, or additionally, the report format editor 104 may comprise code to 1) associate a name with each of the placed representations of circuit test data 302a, 308a, and 2) cause the name 314 to be displayed when a graphical pointer 316 hovers over its corresponding representation of circuit test data 308a (i.e., a data item's name is displayed when a user “hovers” over the data item). Once a representation of circuit test data 302a, 308a has been placed in the ASCII report format 312, it may be easily dragged and repositioned. Further, the report format editor 104 may comprise code that enables placed representations of circuit test data 302a, 308a to be graphically resized within the ASCII report format 312. This may be accomplished, for example, by providing the circuit test data 302a, 308a with graphically selectable “handles” (e.g., persistently displayed handles or hover (pop-up) handles). In one embodiment, selection of a placed representation of circuit test data 302a (e.g., via a mouse-click) also causes the GUI 300 to provide an option to specify a data format for the selected representation. The option may take the form of a fill-in field (on a menu bar, for example) that allows a user to specify a desired width of circuit test data, a desired number of significant digits of the data item, or one of an number of data formats for data item (e.g., integer, text, or scientific notation). FIG. 5 shows an embodiment of the report format editor 104 wherein each representation of circuit test data 302a, 308a is, by default, associated with a number of programmable label fields (label_a-label_c for item 308a, and label_d-label_f for item 302a). By way of example, the programmable label fields may comprise a column header field (label_a, label_d), a preamble field (label_b, label_e), and a postamble field (label_c, label_f). By clicking on one of the fields, a user can fill in the field with a title, measurement unit, mathematical indicator, separator character (e.g., a colon), or other information that improves report readability. The user might also be given an option to delete or hide some or all of the label fields. Alternately, or additionally, the menus of the report format editor's GUI may provide a user with various options to place context fields 600, 602, 604, 606 in the ASCII report format. As shown in FIG. 6, these context fields 600-606 may comprise various sorts of text and/or numeric fields. Although a variety of means for configuring an ASCII report format 312 have been disclosed, it is preferable that all of the means be implemented using a non-proportional font, and that a user is displayed a WYSIWYG (what you see is what you get) report format. Further, although the figures show only a single row of columns, the GUI 300 of the report format editor 104 could alternately show multiple rows of columns. Alternately, the GUI 300 of the report format editor 104 could display multiple formatting windows, each of which corresponds to a tier in a hierarchical report. For example, a report might comprise tiers for: lot, cassette, wafer, and device. Each window might appear as shown in FIG. 3. While illustrative and presently preferred embodiments of the invention have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed, and that the appended claims are intended to be construed to include such variations, except as limited by the prior art. | <SOH> BACKGROUND OF THE INVENTION <EOH>Some circuit test systems output circuit test data in accordance with a fixed report format. Other circuit test systems allow circuit test data to be mapped to arbitrary locations. However, these latter circuit test systems require a user to understand low-level details of the system's output data, as well as a programming language such as “C”. | <SOH> SUMMARY OF THE INVENTION <EOH>One aspect of the invention is embodied in a report format editor for circuit test. The editor comprises code to display a graphical user interface (GUI). The GUI, in turn, displays 1) a number of user-selectable representations of circuit test data, and 2) a user-modifiable ASCII report format that is formed, at least in part, of placed ones of the user-selectable representations of circuit test data. Program code interprets relative sizes and placements of elements forming the user-modifiable ASCII report format and generates an ASCII format description file in response to the interpretation. Other embodiments of the invention are also disclosed. | 20040402 | 20060822 | 20051006 | 95144.0 | 0 | ASSOUAD, PATRICK J | REPORT FORMAT EDITOR FOR CIRCUIT TEST | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,817,359 | ACCEPTED | Using multiple types of phosphor in combination with a light emitting device | Light is emitted from a light emitting device. The light emitted from the light emitting device is combined with light from a first type of phosphor and a second type of phosphor. The first type of phosphor and the second type of phosphor are within an epoxy placed over the light emitting device. The first type of phosphor, when excited, emits light of a first color. The second type of phosphor, when excited, emits light of a second color. The first color and the second color are different. | 1. A light generating device comprising: a light emitting device; and, an epoxy placed over the light emitting device, the epoxy including: a first type of phosphor, and a second type of phosphor; wherein the first type of phosphor, when excited, emits light of a first color; wherein the second type of phosphor, when excited, emits light of a second color; and, wherein the first color and the second color are different. 2. A light generating device as in claim 1 wherein the light emitting device is a blue light emitting diode, wherein the first type of phosphor is a green phosphor, and wherein the second type of phosphor is a yellow phosphor. 3. A light generating device as in claim 1: wherein the light emitting device is a blue light emitting diode; wherein the first type of phosphor is one of the following: Strontium Thiogallate:Europium, having a chemical formula of SrGa2S4:Eu, a thiogallate phosphor that is a mix group II alkaline metal thiogallate phosphor (Sr,Ca,Ba)(Al,Ga)2S4:Eu; BaSrGa4S7:Eu; and, wherein the second type of phosphor is a yellow phosphor having one of the following chemical formulas: Tb3Al5O12:Ce, Sr(Ba,Ca)SiO4:Eu, YAG:Ce. 4. A light generating device as in claim 1 additionally comprises one of the following: a mold compound covering the epoxy; an optical dome covering the epoxy. 5. A light generating device as in claim 1 wherein the first type of phosphor is a red phosphor, and wherein the second type of phosphor is a yellow phosphor. 6. A light generating device as in claim 1: wherein the first type of phosphor is a red phosphor having one of the following chemical formulas: CaS:Eu2+,Mn2+, SrS:Eu2+, (Zn,Cd)S:Ag+, Mg4GeO5.5F:Mn4+, ZnS:Cu+, ZnSe:Cu, Cl, ZnSe1/2S1/2:CU,Cl, BaSi7N10:Eu2+, (Ca,Sr,Ba)Si5N8:Eu2+; and, wherein the second type of phosphor is a yellow phosphor having one of the following chemical formulas: Tb3Al5O12:Ce, Sr(Ba,Ca)SiO4:Eu, YAG:Ce. 7. A light generating device as in claim 1 additionally comprising: a second light emitting device; and, a second epoxy placed over the second light emitting device, the second epoxy including: the first type of phosphor, and the second type of phosphor. 8. A light generating device as in claim 1 additionally comprising: a second light emitting device; a second epoxy placed over the second light emitting device, the second epoxy including: the first type of phosphor, and the second type of phosphor; a third light emitting device; and, a third epoxy placed over the third light emitting device, the third epoxy. including: the first type of phosphor, and the second type of phosphor. 9. A light generating device as in claim 1, wherein the light emitting device is mounted on one of the following: a printed circuit board; a lead frame. 10. A light generating device as in claim 1, wherein the light emitting device is mounted within a printed circuit board substrate. 11. A method for generating colored light comprising: emitting light from a light emitting device; and, combining light emitted from light emitting device with light from a first type of phosphor and a second type of phosphor, the first type of phosphor and the second type of phosphor being within an epoxy placed over the light emitting device, wherein the first type of phosphor, when excited, emits light of a first color, wherein the second type of phosphor, when excited, emits light of a second color, and wherein the first color and the second color are different. 12. A method as in claim 11 wherein the light emitting device is a blue light emitting diode, wherein the first type of phosphor is a green phosphor, and wherein the second type of phosphor is a yellow phosphor. 13. A method as in claim 11: wherein the light emitting device is a blue light emitting diode; wherein the first type of phosphor is one of the following: Strontium Thiogallate:Europium, having a chemical formula of SrGa2S4:Eu; a thiogallate phosphor that is a mix group II alkaline metal thiogallate phosphor (Sr,Ca,Ba)(Al,Ga)2S4:Eu; BaSrGa4S7:Eu; and, wherein the second type of phosphor is a yellow phosphor having one of the following chemical formulas: Tb3Al5O12:Ce, Sr(Ba,Ca)SiO4:Eu, YAG:Ce. 14. A light generating device comprising: an emitting means for emitting light; and, an holding means for holding a first type of phosphor and a second type of phosphor adjacent to the emitting means; wherein the first type of phosphor, when excited, emits light of a first color; wherein the second type of phosphor, when excited, emits light of a second color; and, wherein the first color and the second color are different. 15. A light generating device as in claim 14 wherein the emitting means is a blue light emitting diode, wherein the first type of phosphor is a green phosphor, and wherein the second type of phosphor is a yellow phosphor. 16. A light generating device as in claim 14: wherein the emitting means is a blue light emitting diode; wherein the first type of phosphor is one of the following: Strontium Thiogallate:Europium, having a chemical formula of SrGa2S4:Eu; a thiogallate phosphor that is a mix group II alkaline metal thiogallate phosphor (Sr,Ca,Ba)(Al,Ga)2S4:Eu; BaSrGa4S7:Eu; and, wherein the second type of phosphor is a yellow phosphor having one of the following chemical formulas: Tb3Al5O12:Ce, Sr(Ba,Ca)SiO4:Eu, YAG:Ce. 17. A light generating device as in claim 16 wherein the first type of phosphor is a red phosphor, and wherein the second type of phosphor is a yellow phosphor. 18. A light generating device as in claim 16: wherein the first type of phosphor is a red phosphor having one of the following chemical formulas: CaS:Eu2+,Mn2+, SrS:EU2+, (Zn,Cd)S:Ag+, Mg4GeO5.5F:Mn4+, ZnS:Cu+, ZnSe:Cu, Cl ZnSe1/2S1/2:CU,Cl, BaSi7N10:Eu2+, (Ca,Sr,Ba)Si5N8:Eu2+; and, wherein the second type of phosphor is a yellow phosphor having one of the following chemical formulas: Tb3Al5O12:Ce, Sr(Ba,Ca)SiO4:Eu, YAG:Ce. 19. A light generating device as in claim 14, wherein the emitting means is mounted on one of the following: a printed circuit board; a lead frame. 20. A light generating device as in claim 14, wherein the emitting means is mounted within a printed circuit board substrate. | BACKGROUND The present invention relates to generation of light and pertains particularly to using multiple types of phosphor in combination with a light emitting device. A conventional single chip light emitting diode (LED) emits a monochromatic color with high purity. Typical colors emitted are pure blue, pure green, pure yellow or pure red. A white LED is produced by incorporating a photoluminescent material called phosphor together with the LED chip. The number of colors that can be achieved by a conventional LED are limited. It is difficult, for example, to obtain colors such as greenish white, reddish white, pinkish white or yellowish green. By using the combination of an LED and a colored phosphor, it is possible to obtain a wider variety of colors. For example, by combining a phosphor that emits yellow light with a blue LED, it is possible to obtain a range of colors from white to bluish white to yellow light. Likewise, using a combination of green phosphor and a blue LED chip, it is possible to obtain a bluish-green color. However, there is a limit to colors that can be achieved by such a combination of blue light with a single color phosphor. For example, yellowish-green and greenish-white colors cannot be produced by a known combination of a blue LED light and a single color phosphor. SUMMARY OF THE INVENTION In accordance with embodiments of the present invention, light is emitted from a light emitting device. The light emitted from the light emitting device is combined with light from a first type of phosphor and a second type of phosphor. The first type of phosphor and the second type of phosphor are within an epoxy placed over the light emitting device. The first type of phosphor, when excited, emits light of a first color. The second type of phosphor, when excited, emits light of a second color. The first color and the second color are different. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a light emitting device, surrounded by an epoxy that includes multiple types of phosphor, packaged as a through-hole lamp in accordance with an embodiment of the present invention. FIG. 2 shows a light emitting device, surrounded by an epoxy that includes multiple types of phosphor, packaged for use in a camera flash module in accordance with another embodiment of the present invention. FIG. 3 shows a light emitting device, surrounded by an epoxy that includes multiple types of phosphor, shown used in a lighting system used in an automotive dashboard in accordance with another embodiment of the present invention. FIG. 4 shows a light emitting device, surrounded by an epoxy that includes multiple types of phosphor, shown used in a high power printed circuit board (PCB) surface mount application in accordance with another embodiment of the present invention. FIG. 5 shows a light emitting device, surrounded by an epoxy that includes multiple types of phosphor, packaged in a lead frame surface mount application in accordance with another embodiment of the present invention. FIG. 6 shows a light emitting device, surrounded by an epoxy that includes multiple types of phosphor, mounted within a PCB in accordance with another embodiment of the present invention. FIG. 7 shows a light emitting device, surrounded by an epoxy that includes multiple types of phosphor, packaged for use as backlighting in accordance with another embodiment of the present invention. DESCRIPTION OF THE EMBODIMENT FIG. 1 shows a through-hole lamp that includes a liquid encapsulation epoxy 13, a pin 14 and a pin 15. A light emitting device 11 is mounted within the through-hole lamp. Light emitting device 11 is covered by an epoxy 12 that includes multiple types of phosphor. For example, epoxy 12 is a liquid epoxy that includes green phosphor and yellow phosphor. For example light emitting device 11 is a blue light emitting diode (LED). Alternatively, other color phosphors and/or LED may be utilized. The mixture of green phosphor plus yellow phosphor plus blue LED allows color ranges from bluish-green to greenish-white to yellowish-green to be obtained. By adjusting the mixture and ratio of green phosphor and yellow phosphor, a wide variety of colors in this color spectrum can be obtained. For example, the green phosphor is Strontium Thiogallate: Europium, having a chemical formula of SrGa2S4:Eu. The green phosphor is spherical in shape and has a mean particle size ranging from 1 micron (μm) to 30 μm. The green phosphor can be efficiently excited by a blue light source generating a blue light with a wavelength from a range of 460 nanometers (nm) to 480 nm. Thus excited, the green phosphor emits green light with peak emission at a wavelength of 535 nm (CIE 1931 color coordinates x=0.270, y=0.683). Alternatively, the green phosphor can have a different chemical formula. For example, the green phosphor can include BaGa4S7:Eu, or a wider coverage of the thiogallate phosphor that is a mix group II alkaline metal thiogallate phosphor (Sr,Ca,Ba)(Al,Ga)2S4:Eu; BaSrGa4S7:Eu. For example, the yellow phosphor has a chemical formula of Tb3Al5O12:Ce. The yellow phosphor is spherical in shape and has a mean particle size ranging from 1 μm to 30 μm. The yellow phosphor can be efficiently excited by a blue light source generating a blue light with a wavelength from a range of 460 nanometers (nm) to 480 nm. Thus excited, the yellow phosphor emits yellow light with peak emission at a wavelength of 575 nm (CIE 1931 color coordinates x=0.467, y=0.522). Alternatively, the yellow phosphor can include a silicate based phosphor such as Sr(Ba,Ca)SiO4:Eu or can also include YAG:Ce. For example, light emitting device 11 emits blue light with peak wavelength ranges from 460 nm to 480 nm. In another embodiment of the invention, using red phosphor, for example in combination with yellow phosphor, allows other color ranges to be obtained. For example, the red phosphor can be composed of a sulfide based phosphor such as one of the following: CaS:Eu2+,Mn2+; SrS:Eu2+; (Zn,Cd)S:Ag+; ZnS: Cu+; ZnSe:Cu, Cl; ZnSe1/2S1/2:Cu,Cl. The red phosphor can also be nitride base with, for example, a chemical formula of: (Ca,Sr,Ba)2Si5N8:Eu2+; BaSi7N10:Eu2+. The red phosphor also can be composed of other phosphors such as Mg4GeO5.5F:Mn4+. FIG. 2 shows a camera flash module having a light emitting device 24, a light emitting device 25 and a light emitting device 26 mounted on a printed circuit board (PCB) 26. A wire 27 is connected between light emitting device 24 and a contact region 23. A wire 28 is connected between light emitting device 25 and contact region 23. A wire 29 is connected between light emitting device 26 and contact region 23. A contact region 22 is also shown. The flash module is covered by a mold compound 34. Light emitting device 24 is covered by an epoxy 31 that includes multiple types of phosphor. For example, epoxy 31 is a liquid epoxy that includes green phosphor and yellow phosphor. Light emitting device 25 is covered by an epoxy 32 that includes green phosphor and yellow phosphor. Light emitting device 26 is covered by an epoxy 33 that includes green phosphor and yellow phosphor. For example, light emitting device 24, light emitting device 25 and light emitting device 26 are each blue LED chips. The mixture of green phosphor plus yellow phosphor plus the blue LED allows color ranges from bluish-green to greenish-white to yellowish-green to be obtained. By adjusting the mixture and ratio of green phosphor and yellow phosphor, a wide variety of colors in this color spectrum can be obtained. For example, the green phosphor is Strontium Thiogallate: Europium, having a chemical formula of SrGa2S4:Eu. The green phosphor is spherical in shape and has a mean particle size ranging from 1 micron (μm) to 30 μm. The green phosphor can be efficiently excited by a blue light source generating a blue light with a wavelength from a range of 460 nanometers (nm) to 480 nm. Thus excited, the green phosphor emits green light with peak emission at a wavelength of 535 nm (CIE 1931 color coordinates x=0.270, y=0.683). Alternatively, the green phosphor can have a different chemical formula. For example, the green phosphor can include BaGa4S7:Eu, or a wider coverage of the thiogallate phosphor that is a mix group II alkaline metal thiogallate phosphor (Sr,Ca,Ba)(Al,Ga)2S4:Eu; BaSrGa4S7:Eu. For example, the yellow phosphor has a chemical formula of Tb3Al5O12:Ce. The yellow phosphor is spherical in shape and has a mean particle size ranging from 1 μm to 30 μm. The yellow phosphor can be efficiently excited by a blue light source generating a blue light with a wavelength from a range of 460 nanometers (nm) to 480 nm. Thus excited, the yellow phosphor emits yellow light with peak emission at a wavelength of 575 nm (CIE 1931 color coordinates x=0.467, y=0.522). Alternatively, the yellow phosphor can include a silicate based phosphor such as Sr(Ba,Ca)SiO4:Eu and can also include YAG:Ce. For example, light emitting device 24, light emitting device 25 and light emitting device 26 emit blue light with peak wavelength ranges from 460 nm to 480 nmn. Alternatively, other color phosphors and light emitting device may be utilized. For example, using red phosphor in combination with yellow phosphor, allows other color ranges to be obtained. For example, the red phosphor can be composed of a sulfide based phosphor such as one of the following: CaS:Eu2+,Mn2+; SrS:Eu2+; (Zn,Cd)S:Ag+; ZnS:Cu+; ZnSe:Cu, Cl; ZnSe1/2S1/2:Cu,Cl. The red phosphor can also be nitride base with, for example, a chemical formula of: (Ca,Sr,Ba)2Si5N8:Eu2+; BaSi7N10:Eu2+. The red phosphor also can be composed of other phosphors such as Mg4GeO5.5F:Mn4+. FIG. 3 shows a portion of an automotive dashboard. A substrate 41 includes an electrode 42 and electrodes 43. A light emitting device 46 is mounted over electrode 42. A wire 47 is connected between light emitting device 46 and electrode 42. Walls 44 define a region in which is placed an epoxy 45. Epoxy 45 includes multiple types of phosphor. For example, epoxy 45 is a liquid epoxy that includes green phosphor and yellow phosphor. For example, light emitting device 46 is a blue LED chip. The mixture of green phosphor plus yellow phosphor plus the blue LED chip allows color ranges from bluish-green to greenish-white to yellowish-green to be obtained. By adjusting the mixture and ratio of green phosphor and yellow phosphor, a wide variety of colors in this color spectrum can be obtained. Alternatively, other color phosphors and light emitting device may be utilized. For example, the green phosphor is Strontium Thiogallate: Europium, having a chemical formula of SrGa2S4:Eu. Alternatively, the green phosphor can have a different chemical formula. For example, the green phosphor can include BaGa4S7:Eu, or a wider coverage of the thiogallate phosphor that is a mix group II alkaline metal thiogallate phosphor (Sr,Ca,Ba)(Al,Ga)2S4:Eu; BaSrGa4S7:Eu. For example, the yellow phosphor has a chemical formula of Tb3Al5O12:Ce. Alternatively, the yellow phosphor can include a silicate based phosphor such as Sr(Ba,Ca)SiO4:Eu and can also include YAG:Ce. Red phosphor can also be used. The red phosphor can be composed of a sulfide based phosphor such as one of the following: CaS:Eu2+,Mn2+; SrS:Eu2+; (Zn,Cd)S:Ag+; ZnS: Cu+; ZnSe:Cu, Cl; ZnSe1/2S1/2:Cu,Cl. The red phosphor can also be nitride base with, for example, a chemical formula of: (Ca,Sr,Ba)2Si5N8:Eu2+; BaSi7N10:Eu2+. The red phosphor also can be composed of other phosphors such as Mg4GeO5.5F:Mn4+. For example, light emitting device 46 emits blue light with peak wavelength ranges from 460 nm to 480 nm. FIG. 4 shows a light emitting device 52, placed in a high power (e.g. 1 Watt) surface mount configuration on a PCB 51. A wire 53 is connected between light emitting device 52 and PCB 51. Epoxy 54 includes multiple types of phosphor. For example, epoxy 54 is a liquid epoxy that includes green phosphor and yellow phosphor. A mold compound 55 is placed over epoxy 54. For example, light emitting device 52 is a blue LED chip. The mixture of green phosphor plus yellow phosphor plus the blue LED chip allows color ranges from bluish-green to greenish-white to yellowish-green to be obtained. By adjusting the mixture and ratio of green phosphor and yellow phosphor, a wide variety of colors in this color spectrum can be obtained. Alternatively, other color phosphors, such as a red phosphor, and light emitting device may be utilized. For example, the green phosphor is Strontium Thiogallate: Europium, having a chemical formula of SrGa2S4:Eu. Alternatively, the green phosphor can have a different chemical formula. For example, the green phosphor can include BaGa4S7:Eu, or a wider coverage of the thiogallate phosphor that is a mix group II alkaline metal thiogallate phosphor (Sr,Ca,Ba)(Al,Ga)2S4:Eu; BaSrGa4S7:Eu. For example, the yellow phosphor has a chemical formula of Tb3Al5O12:Ce. Alternatively, the yellow phosphor can include a silicate based phosphor such as Sr(Ba,Ca)SiO4:Eu and can also include YAG:Ce. Red phosphor can also be used. The red phosphor can be composed of a sulfide based phosphor such as one of the following: CaS:Eu2+,Mn2+; SrS:Eu2+; (Zn,Cd)S:Ag+; ZnS:Cu+; ZnSe:Cu, Cl; ZnSe1/2S1/2:Cu,Cl. The red phosphor can also be nitride base with, for example, a chemical formula of: (Ca,Sr,Ba)2Si5N8:Eu2+; BaSi7N10:Eu2+. The red phosphor also can be composed of other phosphors such as Mg4GeO5.5F:Mn4+. For example, light emitting device 52 emits blue light with peak wavelength ranges from 460 nm to 480 nm. FIG. 5 shows a light emitting device 63 placed in a surface mount configuration on a leadframe portion 61. A wire 64 is connected between light emitting device 63 and leadframe portion 61. A wire 65 is connected between light emitting device 63 and a leadframe portion 62. Epoxy 66 includes multiple types of phosphor. For example, epoxy 66 is a liquid epoxy that includes green phosphor and yellow phosphor. For example, light emitting device 63 is a blue LED chip. The mixture of green phosphor plus yellow phosphor plus the blue LED chip allows color ranges from bluish-green to greenish-white to yellowish-green to be obtained. By adjusting the mixture and ratio of green phosphor and yellow phosphor, a wide variety of colors in this color spectrum can be obtained. Alternatively, other color phosphors and light emitting device may be utilized. For example, the green phosphor is Strontium Thiogallate: Europium, having a chemical formula of SrGa2S4:Eu. Alternatively, the green phosphor can have a different chemical formula. For example, the green phosphor can include BaGa4S7:Eu, or a wider coverage of the thiogallate phosphor that is a mix group II alkaline metal thiogallate phosphor (Sr,Ca,Ba)(Al,Ga)2S4:Eu; BaSiGa4S7:Eu. For example, the yellow phosphor has a chemical formula of Tb3Al5O12:Ce. Alternatively, the yellow phosphor can include a silicate based phosphor such as Sr(Ba,Ca)SiO4:Eu and can also include YAG:Ce. Red phosphor can also be used. The red phosphor can be composed of a sulfide based phosphor such as one of the following: CaS:Eu2+,Mn2+; SrS:Eu2+; (Zn,Cd)S:Ag+; ZnS:Cu+; ZnSe:Cu, Cl; ZnSe1/2S1/2:Cu,Cl. The red phosphor can also be nitride base with, for example, a chemical formula of: (Ca,Sr,Ba)2Si5N8:Eu2+; BaSi7N10:Eu2+. The red phosphor also can be composed of other phosphors such as Mg4GeO5.5F:Mn4+. For example, light emitting device 63 emits blue light with peak wavelength ranges from 460 nm to 480 nm. FIG. 6 shows a light emitting device 75 mounted on a heat sink 74 within a PCB substrate 71. Vias 72 through PCB substrate 71 make connections between contacts 73. A wire 78 is connected between light emitting device 75 and contacts 73, as shown. Epoxy 76 includes multiple types of phosphor. For example, epoxy 76 is a liquid epoxy that includes green phosphor and yellow phosphor. An optical dome 77 is placed over epoxy 76. For example, light emitting device 75 is a blue LED chip. The mixture of green phosphor plus yellow phosphor plus the blue LED chip allows color ranges from bluish-green to greenish-white to yellowish-green to be obtained. By adjusting the mixture and ratio of green phosphor and yellow phosphor, a wide variety of colors in this color spectrum can be obtained. Alternatively, other color phosphors and light emitting device may be utilized. For example, the green phosphor is Strontium Thiogallate: Europium, having a chemical formula of SrGa2S4:Eu. Alternatively, the green phosphor can have a different chemical formula. For example, the green phosphor can include BaGa4S7:Eu, or a wider coverage of the thiogallate phosphor that is a mix group II alkaline metal thiogallate phosphor (Sr,Ca,Ba)(Al,Ga)2S4:Eu; BaSrGa4S7:Eu. For example, the yellow phosphor has a chemical formula of Tb3Al5O12:Ce. Alternatively, the yellow phosphor can include a silicate based phosphor such as Sr(Ba,Ca)SiO4:Eu and can also include YAG:Ce. Red phosphor can also be used. The red phosphor can be composed of a sulfide based phosphor such as one of the following: CaS:Eu2+,Mn2+; SrS:Eu2+; (Zn,Cd)S:Ag+; ZnS: Cu+; ZnSe:Cu, Cl; ZnSe1/2S1/2:Cu,Cl. The red phosphor can also be nitride base with, for example, a chemical formula of: (Ca,Sr,Ba)2Si5N8:Eu2+; BaSi7N10:Eu2+. The red phosphor also can be composed of other phosphors such as Mg4GeO5.5F:Mn4+. For example, light emitting device 75 emits blue light with peak wavelength ranges from 460 nm to 480 nm. FIG. 7 shows a light emitting device 82 mounted on a PCB 81 in a configuration used, for example, to provide backlighting for a device such as a phone or personal digital assistant (PDA). A wire 83 is connected between light emitting device 82 and PCB 81. Epoxy 84 includes multiple types of phosphor. For example, epoxy 84 is a liquid epoxy that includes green phosphor and yellow phosphor. For example, light emitting device 82 is a blue LED chip. The mixture of green phosphor plus yellow phosphor plus the blue LED chip allows color ranges from bluish-green to greenish-white to yellowish-green to be obtained. By adjusting the mixture and ratio of green phosphor and yellow phosphor, a wide variety of colors in this color spectrum can be obtained. Alternatively, other color phosphors and light emitting device may be utilized. For example, the green phosphor is Strontium Thiogallate: Europium, having a chemical formula of SrGa2S4:Eu. Alternatively, the green phosphor can have a different chemical formula. For example, the green phosphor can include BaGa4S7:Eu, or a wider coverage of the thiogallate phosphor that is a mix group II alkaline metal thiogallate phosphor (Sr,Ca,Ba)(Al,Ga)2S4:Eu; BaSrGa4S7:Eu. For example, the yellow phosphor has a chemical formula of Tb3Al5O12:Ce. Alternatively, the yellow phosphor can include a silicate based phosphor such as Sr(Ba,Ca)SiO4:Eu and can also include YAG:Ce. Red phosphor can also be used. The red phosphor can be composed of a sulfide based phosphor such as one of the following: CaS:Eu2+,Mn2+; SrS:Eu2+; (Zn,Cd)S:Ag+; ZnS:Cu+; ZnSe:Cu, Cl; ZnSe1/2S1/2:Cu,Cl. The red phosphor can also be nitride base with, for example, a chemical formula of: (Ca,Sr,Ba)2Si5N8:Eu2+; BaSi7N10:Eu2+. The red phosphor also can be composed of other phosphors such as Mg4GeO5.5F:Mn4+. For example, light emitting device 82 emits blue light with peak wavelength ranges from 460 nm to 480 nm. The foregoing discussion discloses and describes merely exemplary methods and embodiments of the present invention. As will be understood by those familiar with the art, the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims. | <SOH> BACKGROUND <EOH>The present invention relates to generation of light and pertains particularly to using multiple types of phosphor in combination with a light emitting device. A conventional single chip light emitting diode (LED) emits a monochromatic color with high purity. Typical colors emitted are pure blue, pure green, pure yellow or pure red. A white LED is produced by incorporating a photoluminescent material called phosphor together with the LED chip. The number of colors that can be achieved by a conventional LED are limited. It is difficult, for example, to obtain colors such as greenish white, reddish white, pinkish white or yellowish green. By using the combination of an LED and a colored phosphor, it is possible to obtain a wider variety of colors. For example, by combining a phosphor that emits yellow light with a blue LED, it is possible to obtain a range of colors from white to bluish white to yellow light. Likewise, using a combination of green phosphor and a blue LED chip, it is possible to obtain a bluish-green color. However, there is a limit to colors that can be achieved by such a combination of blue light with a single color phosphor. For example, yellowish-green and greenish-white colors cannot be produced by a known combination of a blue LED light and a single color phosphor. | <SOH> SUMMARY OF THE INVENTION <EOH>In accordance with embodiments of the present invention, light is emitted from a light emitting device. The light emitted from the light emitting device is combined with light from a first type of phosphor and a second type of phosphor. The first type of phosphor and the second type of phosphor are within an epoxy placed over the light emitting device. The first type of phosphor, when excited, emits light of a first color. The second type of phosphor, when excited, emits light of a second color. The first color and the second color are different. | 20040402 | 20090210 | 20051013 | 57929.0 | 5 | LOUIE, WAI SING | USING MULTIPLE TYPES OF PHOSPHOR IN COMBINATION WITH A LIGHT EMITTING DEVICE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,817,540 | ACCEPTED | Miniature fluid dispensing end-effector for geometrically constrained areas | An end-effector precisely marks location lines (or dispense fluids) on surfaces as part of an automated part marking system. The automated part marking system that includes a multi-axis gantry robot, a calibration stand, vision or location system(s), and a series of fluid dispensing (inkjet) end-effectors to accomplish the marking task. The end-effector use a pick shaped stylus coupled to a fluid supply and metered by a high-speed pulsed valve to precisely deliver fluids provides within geometrically confined spaces. | 1. A precision marking system to place reference markers on an object that comprises: a work surface on which the object is placed; an object locator system to determine the location and orientation of the object and features within the object relative to the work surface; a multiple axis robot, wherein positioning the multiple axis robot is directed by a control system; and at least one end-effector operable coupled to the multiple axis robot to place reference markers on the object, wherein the end-effector further comprises: an ink delivery system; a pulsed valve to regulate the supply of ink from the ink delivery system; a pick shaped stylus operable coupled to the pulsed valve to receive ink from the pulsed valve, and wherein the pick shaped stylus has an internal orifice through which the ink is dispensed from the end-effector and onto the object. 2. The precision marking system of claim 1, wherein the ink delivery system further comprises an ink reservoir operably coupled to a positive displacement pump. 3. The precision marking system of claim 1, wherein the ink delivery system further comprises a positive pressure pneumatic reservoir delivery system. 4. The precision marking system of claim 1, wherein the pick shaped stylus provide radial clearance around the orifice. 5. The precision marking system of claim 1, wherein the work surface comprises a shuttle table. 6. The precision marking system of claim 5, wherein the shuttle table further comprises a series of vacuum support pins in a predetermined arrangement for a given object. 7. The precision marking system of claim 1, wherein the object locator system further comprises a vision end-effector to locate the object within a work envelope. 8. The precision marking system of claim 1, wherein the multiple axis robot further comprises a 6-axis gantry robot. 9. The precision marking system of claim 1, wherein the reference markers provide alignment information for additional objects to be mechanically coupled to the object. 10. The precision marking system of claim 1, wherein the reference markers provide part identification information. 11. The precision marking system of claim 1, wherein the reference markers provide assembly information to a user. 12. The precision marking system of claim 1, wherein the object further comprises an aircraft understructure. 13. The precision marking system of claim 1, wherein the end-effector is oriented to place reference markers on the surface of the object. 14. The precision marking system of claim 1, wherein the end-effector is oriented to place reference markers on walls located at an angle to the surface of the object. 15. The precision marking system of claim 1, further comprises a calibration system operable to calibrate each end-effector when selected. 16. The precision marking system of claim 1, wherein the end-effector is stored within a storage rack when not operable coupled to the multiple axis robot. 17. An end-effector to place reference markers on an object that comprises: a fluid delivery system; a pulsed valve to regulate the supply of fluids from the fluid delivery system; and a pick shaped stylus operable coupled to the pulsed valve to receive fluids from the pulsed valve, and wherein the pick shaped stylus has an internal orifice through which the fluids are dispensed from the end-effector and onto the object. 18. The end-effector of claim 17, wherein the ink delivery system further comprises an ink reservoir operably coupled to a positive displacement pump. 19. The end-effector of claim 17, wherein the ink delivery system further comprises a positive pressure pneumatic reservoir delivery system. 20. The end-effector of claim 17, wherein the pick shaped stylus provide radial clearance around the orifice. 21. The end-effector of claim 17, wherein the end-effector is operably coupled to a multi axis robot within a precision marking system. 22. The end-effector of claim 21, wherein the precision marking system further comprises: a work surface on which the object is placed; an object locator system to determine the location and orientation of the object and features within the object relative to the work surface; and the multiple axis robot, wherein positioning the multiple axis robot is directed by a control system. 23. The end-effector of claim 17, wherein the fluids further comprise inks, paints, epoxy, or adhesives. | CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of priority to U.S. Provisional Patent Application No. 60/526,034 entitled “Miniature Fluid Dispensing End-Effector for Geometrically Constrained Areas”, filed on Dec. 1, 2003, and is incorporated herein by reference in its entirety. TECHNICAL FIELD OF THE INVENTION The present invention relates generally to parts marking systems and methods, and more particularly, a system and method for delivering fluids to surfaces in geometrically constrained spaces. BACKGROUND OF THE INVENTION Part marking systems address the need to trace components including aircraft, surgical, automotive parts, or other like parts for the duration of their lifetime. These markings can allow parts to be identified and traced to their origin. Additionally these markings can facilitate the assembly of complex structures by providing reference markings or instructions at the assembly point for use in assembling and aligning various parts. To assist in assembly, automated ink-jet marking systems often mark locations of hardware and fasteners on part surfaces. This allows the operators to quickly and accurately locate and align sub-assemblies to larger assemblies. Additionally, this avoids the need to construct complicated and expensive jigs to locate sub-assemblies and fasteners. Current inkjet marking systems provide only horizontal or vertical firing. This adequately addresses the marking of horizontal and vertical surfaces. However, this fails to address the need to appropriately mark components with geometrically confined spaces or surfaces at non-normal angles to the ink-jet marking system. Currently, known parts marking systems lack the ability to handle irregular shaped and cylindrical parts having various surface projections such as flanges or stiffeners that are located at non-normal angles to the parts surface. Previously these complex structures were marked by hand or required expensive and unique tooling in order to properly mark attachment locations for the machining of the part. Additionally, because current inkjet effecters fire only in the horizontal or in the vertical direction, alignment errors may be induced on non-planar surfaces by the angle between the ink stream and the surface normal of the part to be marked. Another problem arises from constraints associated with part geometry depending on the depth and the size of the area to be marked as existing marking heads cannot reach into confined spaces. FIG. 1 illustrates the problems associated with marking parts or components 10 wherein the surface normal 12 is at a non-zero angle to the ink stream 14 supplied by the marking head. This results in a displacement of the marking from an intended surface 16 to the actual surface 18. Significant alignment errors can be experienced due to an accumulated effect of incorrectly synchronizing system alignments as indicated in the graph provided in FIG. 2. These additive errors include: (1) the alignment of the calibration monument; (2) end effector (tool centerpoint (TCP)); (3) vision or parts location system (vision system centerpoint); (4) part alignment and orientation in space; and (5) work envelope of the robot. Therefore a need exists for a parts marking system capable of accurately marking parts having surfaces located at a non-normal angles to the end-effector or within confined spaces. SUMMARY OF THE INVENTION The present invention provides an automated part marking system that substantially eliminates or reduces disadvantages and problems associated with previously developed systems and methods. More specifically, the present invention provides a system and method to very precisely mark location lines (or dispenses fluids) on surfaces such as bulkheads and frames of an aircraft understructure. The lines aid in visually locating smaller parts (such as brackets and clips) relative to the bulkheads. This allows smaller parts to be fastened in the appropriate position without the need for traditional and expensive custom tooling. One embodiment provides an automated part marking system that includes a 6-axis gantry robot, a calibration stand, vision or location system(s), and a series of fluid dispensing (ink-jet) end-effectors to accomplish the marking task. The end-effector provides the ability to access geometrically confined spaces. This ability was not available in previous end-effectors due to limitations imposed by the size of available inkjet heads for the end-effector. Miniaturization/Optimization of the end-effector's dispensing tip improves the system parameters of part population, system accuracy, and system communication potential. Improving this ability greatly improves the functionality of the part marking system. Furthermore, the dispensing tip provides access into very tight spaces. This end-effector addresses the space limitations identified above and provides access into very tight spaces. This is achieved in part by efficiently packaging components of a dispensing system within a small space. The stylus/probe of the dispensing tip resembles a dental pick and has an internal orifice with which the fluids are dispensed. The radial clearance provided around the orifice improves the part population candidates of the part marking system. This end-effector uses a high-speed pulsed valve and orifice within the dispensing tip joined by umbilical tubing to dispense the fluids. Either positive displacement pumps, positive pressure pneumatic reservoir or syringe, or other like delivery systems are used to supply the fluid to the dispensing tip. When compared to traditional systems, this end-effector allows the parts marking system to improve from marking within a Dixie cup, to marking within a thimble. The dispensing end-effector stylus being much smaller than previously styluses, allows access to tight spaces giving either a best-case radial clearance between the end-effector hardware and part geometry, or a best-case part marking capability when marking adjacent walls and floors. The dispensing end-effector stylus does this while allowing the fluid to remain normal to the intended surface for improved accuracy. Additionally, replaceable items are kept both inexpensive and interchangeable to reduce cost without sacrificing the end-effectors' maintainability or reliability. The dispensing end-effector stylus improves the accuracy of the parts marking system. This improved accuracy results in increased locations where markings can be applied. This allows engineering datum and location lines to be more accurately drawn for improved alignment of the brackets. Additionally, this dispensing tip provides increased throwing distances for the dispensed fluids, helping to reduce errors and improve accuracy. This improved accuracy results by minimizing potential elevation errors in the intended marks location if the wall is further away than expected. The dispensing end-effector stylus improves the parts marking systems communication potential. The end-effector allows the system to mark more of the bracket footprint than was previously possible. Doing so minimizes the need for supporting documentation required to assemble components. Additionally, this dispensing tip allows higher viscosity fluids such as inks, paints, epoxy, or adhesives to be dispensed on the surface. When compared to existing systems, this dispensing tip reduces required daily maintenance, eliminates the need to frequently empty and refill and avoids clogging with better suited fluids that address meniscus formation issues. Fewer clogging issues are present due to a wider selection of fluids available when using positive pressure displacement systems to deliver the fluids. In previous solutions a piezo-electric valve is used to control the fluid's drop velocity, wherein the drop velocity depended on the voltage applied to the valve. The dispensing end-effector stylus provides an important technical advantage in that its design allows this end-effector to be easily retrofitted on the existing marking system with only minor adjustments. The parts marking system provided in this disclosure may be used by any manufacturer, which needs to precisely control the delivery of fluid into a geometrically constrained area. Thus, the present invention may be applied to aerospace, automotive, as well as other industries that require the ability to precisely deliver fluid into constrained spaces. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings in which like reference numerals indicate like features and wherein: FIG. 1 illustrates problems associated with existing marking heads as applied to parts having confined geometry spaces; FIG. 2 is a graph depicting alignment errors associated with existing parts marking systems; FIG. 3 provides a perspective view of one embodiment of a precision marking system in accordance with the present invention; FIG. 4 provides a top-down view of one embodiment of a precision marking system in accordance with the present invention; FIG. 5 provides a top-down view of a second embodiment of a precision marking system having a robot operably coupled to multiple end effectors; FIG. 6 depicts in further detail and scale the robot of FIGS. 3, 4 and 5; FIG. 7 depicts one embodiment of an end-effector to dispense fluid in accordance with the present invention; FIG. 8 depicts end-effectors that dispense fluids in geometrically constrained spaces; FIG. 9 depicts an end-effector operable to dispense fluids in a geometrically confined space with a surface at a non-normal angle to the surface of the part; FIG. 10 provides a side profile view of a dispensing tip in accordance with the present invention as compared to existing marking or fluid dispensing heads; FIG. 11 provides a head on view of the dispensing tip of the present invention comparing the marking head and fluid dispensing system of currently available systems; FIG. 12 provides a perspective view of one embodiment of an end effector in accordance with the present invention as compared to existing end-effectors used to dispense marking inks; FIG. 13 depicts the poor resolution associated with current marking systems; FIG. 14 illustrates the improved quality of markings available with the end effector provided in accordance with the present invention; and FIGS. 15 through 19 illustrate the various surfaces on which an end effector in accordance with the present invention may be used to dispense fluids or draw reference lines. DETAILED DESCRIPTION OF THE INVENTION Preferred embodiments of the present invention are illustrated in the FIGUREs, like numerals being used to refer to like and corresponding parts of the various drawings. An Automated Part Marking System helps reduce costs associated with assembling structural components, such as airframes by producing marks accurate enough for operators to locate parts and drill holes (without tooling). This system helps to ensure that assembly tolerances are repeatably maintained. The Automated Part Marking System helps eliminate tooling development, rework, and maintenance costs. Additionally, the system functionally operates by modularly locating and marking the larger structural components for the eventual location of smaller detail parts. These smaller detail parts are typically brackets used to secure subsystem components, and their installation occurs at varying times (later) in the assembly process. A Part Marking Robotic Work Cell is employed which in one embodiment has an estimated Work Cell Footprint of approximately 80′×60′, with an estimated robot and shuttle footprint of 80′×20′, estimated gantry work envelope of 16′×9′×2′, and an estimated shuttle table of 14′×6′. The work cell includes a work cell controller, a shuttle transfer mechanism (including two shuttle tables), tooling plates, a six-axis gantry robot, a series of end-effectors, a quick-change end-effector stand, a vision calibration system, and additional ancillary hardware, software, and firmware. The work cell controller integrates automated work cell activities. The shuttle transfer system acts as a material handling and part docking mechanism for introducing the shuttle tables and parts into the work envelope. Tooling plates accurately and repeatably locate parts on the shuttle tables. The robot moves the marker heads along pre-programmed paths. The end-effectors allow customized line and text marking with ink-jet heads, and force-sensing probes. The end-effectors are fully functional and integrated with simultaneous axis robot movements. Additionally, the end-effectors support quick-changes during the part marking process and have failsafe collision detection mechanisms designed in. The vision calibration system helps ensure system accuracy by examining the actual end-effector probe alignment, nozzle rotation, and part mark location against theoretical. This comparison allows compensational adjustments for any variability that exists. The Automated Part Marking System produces lines and curves on vertical, horizontal, and contoured parts with exceptional precision. These lines will help in visually locating bracket edge positions for assembly. The Automated Part Marking System also produces line-based symbols on vertical, horizontal, and contoured part features with exceptional precision. These symbols may define the position of mounting holes, as well as communicate differences in their attachment procedures. The Automated Part Marking System may also produce legible text on flat surfaces. The text helps identify the parts to be assembled in near-by locations, and provide other types of helpful work instructions. The end-effectors may use quick-change adaptor that prevents the end-effector from uncoupling from the robot in the event of air, vacuum, power, or other utility loss. Additionally, an integrated force-sensing, or multi-clutch mechanism may detect both moment and in-line axial forces to the probes themselves. This force sensor may include a Tactile Calibration Head integrated from off-the-shelf technology as known to those skilled in the art. FIG. 3 provides a perspective view of one embodiment of a precision marking system 20 used to place reference markers on object 32 in accordance with the present invention. FIG. 4 provides a top-down view of one embodiment of a precision marking system 20 used to place reference markers on object 32. Object 32 may be a structure such as the understructure of an aircraft. Object 32 is placed on a work surface 30. Aircraft understructures or like objects require the locations for subsequent installation of various brackets, clips, grommets, etc. be precisely marked. The brackets and clips hold various equipment and utilities, where alignment of these pieces is critical. In one embodiment, objects are brought into the work envelop with Dual Platen Shuttle Tables. The work surface may use a vacuum system and a combination of pins and plugs to hold the objects rigidly on the table. A robot 34 with multiple degrees of freedom and axes of rotation allows interchangeable end-effectors 36 to be positioned precisely relative to work surface 30 and object 32. As depicted, a fluid dispensing end-effector is shown coupled to robot 34. However, other end-effectors may be used to locate and perform other manufacturing processes. This marking end-effector facilitates the part marking process. One such end-effector is described in further detail within the description of FIG. 7. Although a gantry type robot is depicted, other robots with the necessary range and freedom of motion may be employed. Multiple interchangeable end-effectors 36 are maintained within storage rack 38. Calibration stand 39 allows the relative position of robot 34 and end-effector 36 to be calibrated every time it is picked up. Calibration of the marking head requires the system to mark a specific cross-hair pattern on a disposable media. The vision system images this pattern and calculates the actual locations of the markings relative to theoretical. FIG. 5 shows a second embodiment of the precision marking system 20 wherein multiple end-effectors 42 and 36 are coupled to robot 34. Location end-effector 42 may employ a vision system to accurately locate objects 32 within the work envelope 40. However, other comparable locations systems may be substituted for vision end-effector 42. Determining the accurate location of objects 32 within the work envelope 40 allows the relative position between object 32 and end-effectors 36 to be determined. After determining the relative location, marking end-effector 36 accurately applies ink or fluids to object 32. One vision system includes a camera, lens and light ring, and laser line generator permanently mounted to the three-axis wrist 51 of robot 34 and is used to locate object 32 and its features. To locate the object, the vision system moves to a theoretical target location and images the actual location, then determines the X and Y coordinates of specific points or features on the object. An actual location is determined with a combination of imaged features. The elevation of the part is determined with a laser line projected at an angle onto the part. The camera picks up the location of this line and determines the height of the part by comparing where the line is in the image recorded by the camera and where the line is supposed to be based on the angle between the camera and the laser line generator. From these three inputs, a 6-degree part transformation is created by the control system coupled to the precision marking system 20. In addition to locating targets and surfaces, the vision system can find edges of upstanding stiffeners, with the laser line projected across a stiffener and imaged by the camera. Analyzing the image reveals the left or right most end of the line, which represents the location of the desired edge of the stiffener. Images gathered may be used to create local transformations when required for extra precision. FIG. 6 provides an enlarged view of Robot 34, which is coupled to gantry system 53 of FIGS. 3, 4 and 5. Here robot 34 comprises multiple arms segments 48 and 49 coupled together by joints 51 in order to allow robot 34 to reposition the interchangeable end-effector 36 within work envelope 40. Segments 48 and 49 are linked by joints 51, 55 and 57 to provide robot 34 the ability to position end-effector 36 at any point in the X, Y, and Z direction within 3-D work envelope 40. Additionally the ability of joints 51, 55 and 57 to rotate allows end-effector 36 to not only be positioned but rotated at any required angle relative to object 32. FIG. 7 provides a more detailed view of fluid dispensing end-effector 36. End-effector 36 is an interchangeable end-effector having a quick-change adaptor 44, allowing the end-effector 36 to be interchangeably coupled to robot 34 via receiving plate 52 as depicted in FIG. 6. The quick-change adaptor prevents the end-effector from uncoupling from the robot in the event of air, vacuum, power, or other utility loss. Additionally, an integrated force-sensing, or multi-clutch mechanism may detect both moment and in-line axial forces to the probes themselves. This force sensor may include a Tactile Calibration Head integrated from off-the-shelf technology as known to those skilled in the art. Faceplate 46 serves to secure and orient end-effector 36 to the receiving plate 52 of robot 34. To align end-effector 36, alignment features 50, such as holes and/or guide pins, align the end-effector to the receiving plate 52 of the robot. Umbilicals couple to end-effector 36 to provide power, hydraulics, fluids or other supplies to end-effector 36 via robot 34. Mounting plate 54 secures housing 56 that contains various components in the end-effector, to faceplate 46. These components include pump 57, mounting bracket 58, syringe or fluid reservoir 60, filter 62, and internal tubing 63. Alignments points 64 located at the bottom of housing 56 allowed the robot 34 to calibrate and precisely determine the position of the end-effector prior to each usage of the end-effector. Probe 66 receives filtered fluids drawn from reservoir 60 by pump 57 through internal tubing 63. High-speed pulse valve 67 allows this fluid to be precisely metered to dispensing tip's 68 stylus that ends in orifice 70. The low profile nature of dispensing tip 68 allows this end-effector to precisely mark parts or dispense fluids to geometrically confined spaces of objects that could not previously be marked with existing end-effectors. Orifice 70 angles away from dispensing tip 68 in FIG. 7 to facilitate dispensing fluids on a wall extending upwards from the surface (or floor) of object 32. In other embodiments, orifice 70 may be angled to facilitate the disposition of fluids on the floor rather than the wall. An integrated collision detection system (such as force sensing, and/or multi-clutch mechanisms) prevents collisions between the object and the end-effector. Additionally, the dispensing tip is made from material with low coefficient of friction values, part marring in the event of a collision may be prevented. The weak-link failure location designed-in may cause the dispensing tip to snap in the event of catastrophic system failure. FIG. 8 depicts two embodiments wherein dispensing tip 68A has an orifice angled to deposit or dispense fluids on wall 72 of object 32 or on the floor 74 of object 32 with a dispending tip 68B. FIG. 9 illustrates that robot 34 may locate or position end-effector 36 at an angle such that dispensing probe tip 68 are better suited to dispense fluids on wall 72 when wall 72 is not located at an angle normal to the surface of object 32. FIGS. 10, 11, and 12 compare the profile of dispensing tip 68 of the present invention to those of currently available fluid dispensing or ink jet systems. In FIG. 10, a side profile of dispensing tip 68 is compared to currently available ink jet marking head 80 and a prototype fluid dispensing system 82. FIG. 11 provides a front view of dispensing tip 68 as compared to ink jet marking head 80 and fluid dispensing system 82. FIG. 12 combines these views to provide prospective views of end-effector utilizing these different fluid-dispensing systems. Here, end-effector 36 on the right is compared to an ink jet marking head 86 having the ink jet applicator 80 of FIGS. 10 and 11, while end-effector 88 has fluid dispensing head 82 of FIGS. 10 and 11. These FIGUREs clearly evidence one advantage provided by the present invention wherein the dispensing tip increases access to geometrically confined areas. The present invention precision marking system and end-effector provided by reference or supporting documentation on an object allows marking lines to enable users to more quickly and accurately position subassemblies to the object. Furthermore, the present invention may be used to mark attached components to the object for further assembly or use. In addition, marking the object, subassemblies such as flanges stiffeners may be marked for additional subassemblies. FIGS. 13 and 14 depict the improved accuracy associated with dispensing tip 68 over prior marking systems. An example of reference lines using commercially available marking systems is depicted in FIG. 13. Lines do not provide the required accuracy to assemble components that demand. In comparison, more accurate reference markers exemplified by the markings of FIG. 14 facilitate meeting these tight requirements. The reduced profile of the dispensing tip help to reduce or eliminate alignment errors induced by the gap, between the fluid dispensing system and object to be marked. These inaccuracies originally described in FIG. 1 and FIG. 2, are reduced by insuring alignment to surface normal is maintained in all geometrically constrained areas. Part marking system can reduce costs associated with assembling structural components, such as airframes by producing marks accurate enough for operators to locate parts and further machine the part (without expensive custom tooling). This invention helps to ensure that assembly tolerances are repeatably maintained. Custom tooling development, rework, and maintenance costs are greatly reduced by this marking system. The automated part marking system can produce lines and curves on vertical, horizontal, angle, and contoured parts with exceptional precision. These lines visually locate assembly positions. Also, line-based symbols on vertical, horizontal, angled, and contoured part features with exceptional precision. These symbols may define the position of mounting holes, as well as communicate differences in their attachment procedures. Legible text written on surfaces helps identify the parts to be assembled in near-by locations, and provide other types of helpful work instructions. In one embodiment, end-effector 36 can be repositioned by the system controller to follow part contour normals. There, particular attention is paid to the following performance parameters: (1) availability of end-effector to work cell, (2) accuracy of intended line marking, (3) producability of line marking in tight spaces, (4) robustness of operation including reliability, quality, and repeatability of part line mark; and interoperability consistency between copies of end-effectors, and (5) maintainability of operation including interchangeability/replacability of spare parts. This allows the end-effector to be manufactured maximize availability. Replaceable/consumable items (Pumps, Solenoids, Probes, Stylus, Jet Heads, Etc.) may be modular in nature to hasten repairs and improve maintainability. The optimized line-marking accuracy, and repeatable with a reliable quick-change mechanism that maximizes repeatability of end-effector positional accuracy when coupled to the robot. A repeatable and reliable probe locating mechanism maximizes repeatability of the ink jet egress location(s) throughout end-effectors. Programmable lines may be produced by the end-effector as described by TABLE 1. TABLE 1 Line type(s) straight & non-closing curves Width(s) Range 0.020-0.060 inches (Optimal values TBD via trials) Length(s) Range 0.5-7.0 inches typical Formats Solid and dashed Color various The geometrically constrained areas. In one embodiment, these restrictions are as follows: (1) Work volume restricted to 1.0×1.0×4.0 inch cube in axis X, Y, Z respectively; Work volume restricted @+/−100 degrees about tool centerpoint X; Work volume restricted @+/−100 degrees about tool centerpoint y; Work volume restricted @+/−360 degrees about tool centerpoint Z; Mark location all areas of interior walls. Representative Part Markings are Described in TABLE 2: Part Marking Communication Requirements and Symbology Attachment Process Affected Area Fastened pick-up Hole Alignment Assembled Pick-up Hole Alignment (from Define Hole Alignment Object Locating Features Bonded pilot holes in other part) (for assembly of parts) Bracket Square Edges Other Same Same Cross-hairs only when reverse side marking req'd Stud Square Edges N/A N/A N/A Other llot required. Holes in Stud will orient drill requirement N/A Grommet Square Edges N/A N/A Other N/A N/A Ilut Plate Square Edges N/A N/A N/A Other N/A Clamp Square Edges N/A N/A N/A Other N/A N/A The text capability of the end-effector allows the end-effector to mark text with the following constraints in geometrically constrained areas. (1) Work volume restricted to 2.5×2.5×4.0 inch cube in axis X, Y, & Z respectively; (2) Work volume restricted @+/−60 degrees in about tool centerpoint X; (3) Work volume restricted @+/−60 degrees in about tool centerpoint y; (4) Work volume restricted @+/−360 degrees in about tool centerpoint Z; (5) Mark location—all bottom surface area of interior wall (when head is @ 0 Degrees in Axis X and Y); (6) Mark location—top 0.250 inch surface area of side walls (when head is rotated @ 60 degrees in Axis X or Y) with exceptions given to 0.250 inches @ corners; and (7) Mark tolerance—may be +/−0.200 inch in any direction within the defined envelope. The end-effector produces legible text of: various fonts such as Arial (Narrow font desired due to space constraints); Special Characters—Arrow that is proportionally sized and in-line with characters being produced; Font size(s)—6-12 pt; Font style(s)—Regular (Italics, Bold, & Bold Italics desired if sizing constraints permits); Font color(s)—One (black), (Red desired if sizing and cost constraints permits); Font length(s)—18 proportional characters within 2.5 inches. (1) The Ink(s) selected for use in the end-effectors may be selected with ranked attention to: (1) optimization of mark accuracy, (2) optimization of mark quality, (3) ability to repeatably propel itself from ink jet head a specified distances (˜0.100), (4) optimization of dry time, (5) maintainability characteristics of ink within Marking End-effectors, and (6) compliance with safety regulations. These inks selected for use in marking end-effectors may produce accurate and repeatable marks on paint-primed surfaces. The inks selected for use in marking end-effectors selected for use may cure to touch (not smudge) within about 30 seconds after mark is made. Additionally, these ink(s) may not require extensive maintenance provisions (routinely clog in any part of end-effector assembly). Cleansing procedures defined for routine maintenance and optimal performance of ink jet ports may involve solvents compliant with environmental requirements. The present invention provides an end-effector to precisely mark location lines (or dispense fluids) on surfaces as part of an automated part marking system. The automated part marking system that includes a multi-axis gantry robot, a calibration stand, vision or location system(s), and a series of fluid dispensing (inkjet) end-effectors to accomplish the marking task. The end-effector use a pick shaped stylus coupled to a fluid supply and metered by a high-speed pulsed valve to precisely deliver fluids provides within geometrically confined spaces. Improved accuracy is achieved by addressing five additive errors. An integrated calibration monument allows the multi-axis gantry robot to precisely determine the position of the tool centerpoint in space. This alignment is routinely performed. For example, this alignment may be performed as part of every marking process. This alignment may be applied to the vision or parts location system as well. By knowing the relative distance between the tool centerpoint and the parts location in space, the integrated system can accurately determine the parts position and alignment in space. This combined knowledge allows the end effector to accurately place the desired graphics on the part. FIGS. 15 through 19 illustrate the various surfaces on which an end effector in accordance with the present invention may be used to dispense fluids or draw reference lines. As one of average skill in the art will appreciate, the term “substantially” or “approximately”, as may be used herein, provides an industry-accepted tolerance to its corresponding term. Such an industry-accepted tolerance ranges from less than one percent to twenty percent and corresponds to, but is not limited to, component values, integrated circuit process variations, temperature variations, rise and fall times, and/or thermal noise. As one of average skill in the art will further appreciate, the term “operably coupled”, as may be used herein, includes direct coupling and indirect coupling via another component, element, circuit, or module where, for indirect coupling, the intervening component, element, circuit, or module does not modify the information of a signal but may adjust its current level, voltage level, and/or power level. As one of average skill in the art will also appreciate, inferred coupling (i.e., where one element is coupled to another element by inference) includes direct and indirect coupling between two elements in the same manner as “operably coupled”. As one of average skill in the art will further appreciate, the term “compares favorably”, as may be used herein, indicates that a comparison between two or more elements, items, signals, etc., provides a desired relationship. For example, when the desired relationship is that signal 1 has a greater magnitude than signal 2, a favorable comparison may be achieved when the magnitude of signal 1 is greater than that of signal 2 or when the magnitude of signal 2 is less than that of signal 1. Although the present invention is described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the invention as described by the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>Part marking systems address the need to trace components including aircraft, surgical, automotive parts, or other like parts for the duration of their lifetime. These markings can allow parts to be identified and traced to their origin. Additionally these markings can facilitate the assembly of complex structures by providing reference markings or instructions at the assembly point for use in assembling and aligning various parts. To assist in assembly, automated ink-jet marking systems often mark locations of hardware and fasteners on part surfaces. This allows the operators to quickly and accurately locate and align sub-assemblies to larger assemblies. Additionally, this avoids the need to construct complicated and expensive jigs to locate sub-assemblies and fasteners. Current inkjet marking systems provide only horizontal or vertical firing. This adequately addresses the marking of horizontal and vertical surfaces. However, this fails to address the need to appropriately mark components with geometrically confined spaces or surfaces at non-normal angles to the ink-jet marking system. Currently, known parts marking systems lack the ability to handle irregular shaped and cylindrical parts having various surface projections such as flanges or stiffeners that are located at non-normal angles to the parts surface. Previously these complex structures were marked by hand or required expensive and unique tooling in order to properly mark attachment locations for the machining of the part. Additionally, because current inkjet effecters fire only in the horizontal or in the vertical direction, alignment errors may be induced on non-planar surfaces by the angle between the ink stream and the surface normal of the part to be marked. Another problem arises from constraints associated with part geometry depending on the depth and the size of the area to be marked as existing marking heads cannot reach into confined spaces. FIG. 1 illustrates the problems associated with marking parts or components 10 wherein the surface normal 12 is at a non-zero angle to the ink stream 14 supplied by the marking head. This results in a displacement of the marking from an intended surface 16 to the actual surface 18 . Significant alignment errors can be experienced due to an accumulated effect of incorrectly synchronizing system alignments as indicated in the graph provided in FIG. 2 . These additive errors include: (1) the alignment of the calibration monument; (2) end effector (tool centerpoint (TCP)); (3) vision or parts location system (vision system centerpoint); (4) part alignment and orientation in space; and (5) work envelope of the robot. Therefore a need exists for a parts marking system capable of accurately marking parts having surfaces located at a non-normal angles to the end-effector or within confined spaces. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides an automated part marking system that substantially eliminates or reduces disadvantages and problems associated with previously developed systems and methods. More specifically, the present invention provides a system and method to very precisely mark location lines (or dispenses fluids) on surfaces such as bulkheads and frames of an aircraft understructure. The lines aid in visually locating smaller parts (such as brackets and clips) relative to the bulkheads. This allows smaller parts to be fastened in the appropriate position without the need for traditional and expensive custom tooling. One embodiment provides an automated part marking system that includes a 6-axis gantry robot, a calibration stand, vision or location system(s), and a series of fluid dispensing (ink-jet) end-effectors to accomplish the marking task. The end-effector provides the ability to access geometrically confined spaces. This ability was not available in previous end-effectors due to limitations imposed by the size of available inkjet heads for the end-effector. Miniaturization/Optimization of the end-effector's dispensing tip improves the system parameters of part population, system accuracy, and system communication potential. Improving this ability greatly improves the functionality of the part marking system. Furthermore, the dispensing tip provides access into very tight spaces. This end-effector addresses the space limitations identified above and provides access into very tight spaces. This is achieved in part by efficiently packaging components of a dispensing system within a small space. The stylus/probe of the dispensing tip resembles a dental pick and has an internal orifice with which the fluids are dispensed. The radial clearance provided around the orifice improves the part population candidates of the part marking system. This end-effector uses a high-speed pulsed valve and orifice within the dispensing tip joined by umbilical tubing to dispense the fluids. Either positive displacement pumps, positive pressure pneumatic reservoir or syringe, or other like delivery systems are used to supply the fluid to the dispensing tip. When compared to traditional systems, this end-effector allows the parts marking system to improve from marking within a Dixie cup, to marking within a thimble. The dispensing end-effector stylus being much smaller than previously styluses, allows access to tight spaces giving either a best-case radial clearance between the end-effector hardware and part geometry, or a best-case part marking capability when marking adjacent walls and floors. The dispensing end-effector stylus does this while allowing the fluid to remain normal to the intended surface for improved accuracy. Additionally, replaceable items are kept both inexpensive and interchangeable to reduce cost without sacrificing the end-effectors' maintainability or reliability. The dispensing end-effector stylus improves the accuracy of the parts marking system. This improved accuracy results in increased locations where markings can be applied. This allows engineering datum and location lines to be more accurately drawn for improved alignment of the brackets. Additionally, this dispensing tip provides increased throwing distances for the dispensed fluids, helping to reduce errors and improve accuracy. This improved accuracy results by minimizing potential elevation errors in the intended marks location if the wall is further away than expected. The dispensing end-effector stylus improves the parts marking systems communication potential. The end-effector allows the system to mark more of the bracket footprint than was previously possible. Doing so minimizes the need for supporting documentation required to assemble components. Additionally, this dispensing tip allows higher viscosity fluids such as inks, paints, epoxy, or adhesives to be dispensed on the surface. When compared to existing systems, this dispensing tip reduces required daily maintenance, eliminates the need to frequently empty and refill and avoids clogging with better suited fluids that address meniscus formation issues. Fewer clogging issues are present due to a wider selection of fluids available when using positive pressure displacement systems to deliver the fluids. In previous solutions a piezo-electric valve is used to control the fluid's drop velocity, wherein the drop velocity depended on the voltage applied to the valve. The dispensing end-effector stylus provides an important technical advantage in that its design allows this end-effector to be easily retrofitted on the existing marking system with only minor adjustments. The parts marking system provided in this disclosure may be used by any manufacturer, which needs to precisely control the delivery of fluid into a geometrically constrained area. Thus, the present invention may be applied to aerospace, automotive, as well as other industries that require the ability to precisely deliver fluid into constrained spaces. | 20040402 | 20061107 | 20050602 | 99524.0 | 0 | COLILLA, DANIEL JAMES | MINIATURE FLUID DISPENSING END-EFFECTOR FOR GEOMETRICALLY CONSTRAINED AREAS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,817,602 | ACCEPTED | Intensity variation device for training animals | An apparatus for an animal training device including audible and electrical stimulation. A transmitting unit provides control signals to a receiving unit, which includes a receiver, a processor, and a switch connected to a transformer and electrodes. The processor provides signals that result in varying voltages that produce electrical pulses of varying voltage levels, which are applied at the electrodes and provide electrical stimulation of an animal for training. | 1. An apparatus for training an animal in which an audible and a variable level electrical stimulation is applied to the animal, said apparatus comprising: a transmitting unit sending a coded signal having an identification code, a stimulation type code, and a stimulation level code, said stimulation type code including a beep code and a shock code; a receiver responsive to said coded signal from said transmitting unit; a processor for decoding said coded signal; a speaker producing a beep in response to said beep code, said speaker controlled by said processor; a switch controlled by said processor in response to said shock code, said processor controlling a pulse stream applied to said switch, said pulse stream having a voltage level related to a value of said stimulation level code; a transformer electrically connected to said switch, said transformer producing a stimulation pulse stream having a pulse voltage directly to said voltage level applied to said switch; and at least one electrode electrically connected to said transformer and located proximal the animal; whereby said animal is stimulated by said electrode when said electrode is energized by said transformer. 2. The apparatus of claim 1 wherein said pulse stream has a fixed pulse width, a fixed pulse frequency, and a variable amplitude. 3. The apparatus of claim 1 wherein said processor has a plurality of output connections that connect to a plurality of resistors that form a voltage divider network connected to said switch. 4. The apparatus of claim 1 wherein said processor monitors said receiver for said coded signal, verifies said identification code, determines whether a beep is to be generated, determines whether a shock is to be generated, and generates control signals for a specified voltage level. 5. The apparatus of claim 1 wherein said transmitting unit includes a beep switch, a shock switch, and a stimulation level switch. 6. An apparatus for training an animal in which a variable level electrical stimulation is applied to the animal, said apparatus comprising: a processor that monitors for a coded signal, verifies an identification code in said coded signal, determines whether an electrical stimulation is to be generated, and generates control signals for a specified voltage level; a switch controlled by said processor, said processor controlling a voltage level applied to said switch; a transformer electrically connected to said switch, said transformer producing a pulse having a pulse voltage directly related to said voltage level applied to said switch; and at least one electrode electrically connected to said transformer and located proximal the animal; whereby said animal is stimulated by said electrode when said electrode is energized by said transformer. 7. The apparatus of claim 6 wherein said processor determines whether a beep is to be generated and further including a speaker producing a beep, said speaker controlled by said processor. 8. An apparatus for training an animal in which a variable level electrical stimulation is applied to the animal, said apparatus comprising: a processor that monitors said receiver for a coded signal, verifies an identification code in said coded signal, determines whether an electrical stimulation is to be generated, and generates control signals for a specified stimulation level; and a means for producing an electrical stimulation based on an output of said processor. 9. The apparatus of claim 8 wherein said means for producing said electrical stimulation includes producing a stream of pulses having a fixed pulse width, a fixed frequency, and a voltage level related to said specified stimulation level. 10. The apparatus of claim 8 wherein said processor determines whether a beep is to be generated and further including a speaker producing a beep and further including a means for producing a beep. 11. An apparatus for training an animal in which a variable level electrical stimulation is applied to the animal, said apparatus comprising: means for receiving a coded signal; means for decoding said coded signal; and a means for producing an electrical stimulation based on said coded signal. 12. The apparatus of claim 11 wherein said means for producing said electrical stimulation includes producing a stream of pulses having a fixed pulse width and frequency and a voltage level related to said specified stimulation level. 13. The apparatus of claim 11 further including a means for producing a beep. 14. In an apparatus for training an animal in which audible and variable level electrical stimulation is applied to the animal, a memory medium comprising software programmed to provide for controlling the stimulation applied to the animal by a process comprising: a) receiving an electronic signal representing a request message to stimulate the animal, said request message including an identification code and a stimulation level code; b) determining whether an electrical stimulation is to be generated to stimulate the animal; c) generating a first control signal corresponding to said stimulation level code; and d) outputting said control signal to produce a signal having a voltage corresponding to said stimulation level code. 15. The process of claim 14 further including verifying said coded signal from said identification code. 16. The process of claim 14 further including: e) determining whether a beep is to be generated to stimulate the animal; and f) generating a second control signal for operating a sound generating device; 17. A method for training an animal in which audible and variable level electrical stimulation is applied to the animal, said method comprising: a) monitoring for a coded signal representing a request message to stimulate the animal, said coded signal including an identification code and a stimulation level code; b) determining whether an electrical stimulation is requested by said coded signal; c) producing said audible stimulation if requested; and d) producing an electrical stimulation signal applied to the animal if requested, said step of producing said electrical stimulation signal including a processor controlling a signal having a voltage level corresponding to said stimulation level code and said signal applied to a switch. 18. The method of claim 17 further including verifying said coded signal from said identification code. 19. The method of claim 17 further including the steps of: d) determining whether an audible stimulation is requested by said coded signal; and e) producing said audible stimulation if requested. 20. The method of claim 17 wherein said step of producing said electrical stimulation signal includes: determining said voltage level corresponding to said stimulation level code; generating an input pulse stream having a fixed pulse width, a fixed frequency, and a pulse voltage equal to said voltage level; and producing a stimulation pulse stream from said input pulse stream. 21. A method for training an animal in which audible and variable level electrical stimulation is applied to the animal, said method comprising: a) monitoring for a coded signal representing a request message to stimulate the animal, said coded signal including an identification code and a stimulation level code; b) determining whether an electrical stimulation is requested; and c) if said electrical stimulation is requested: c1) determining a voltage level corresponding to said stimulation level code; c2) generating an input pulse stream having a fixed pulse width, a fixed frequency, and a pulse voltage equal to said voltage level; c3) applying said input pulse stream to an output pulse generator; c4) generating an output pulse stream from said input pulse stream; and c4) making said output pulse stream available to the animal. 22. The method of claim 21 further including the steps of: d) determining whether an audible stimulation is requested; and e) producing said audible stimulation if requested; and 23. The method of claim 21 further including a step of verifying said coded signal from said identification code. 24. The method of claim 21 wherein said coded signal includes a stimulation type code. 25. A method for training an animal in which audible and variable level electrical stimulation is applied to the animal, said method comprising: a) monitoring a receiver for a coded signal representing a request message to stimulate the animal, said coded signal including an identification code and a stimulation level code; b) if an electrical stimulation is requested by said coded signal: b1) determining a voltage level corresponding to said stimulation level code; b2) applying to a switch an input pulse stream having a fixed pulse width, a fixed frequency, and a pulse voltage equal to said voltage level; b3) switching a transformer to generate an output pulse stream from said input pulse stream; and b4) making said output pulse stream available to the animal. 26. The method of claim 25 further including the step of: c) controlling an audible device if an audible stimulation is requested by said coded signal. 27. The method of claim 25 wherein said coded signal includes a stimulation type code. 28. The method of claim 25 further including a step of verifying said coded signal from said identification code. | CROSS-REFERENCE TO RELATED APPLICATIONS Not Applicable STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not Applicable BACKGROUND OF THE INVENTION 1. Field of Invention This invention pertains to an apparatus for varying the intensity of stimulation applied during animal training. More particularly, this invention pertains to varying the intensity of stimulation applied to an animal wearing a collar having an attached receiver. The intensity is varied by controlling the voltage applied to a switching device that produces the shock pulses that provide the stimulation to the animal. 2. Description of the Related Art Radio controlled training collars are known for conditioning the behavior of an animal. A transmitter, commonly handheld, is controlled by a trainer. The collar is worn by an animal and includes a receiver that triggers an electrical circuit that applies electrical stimulation to the animal through electrodes in contact with the animal. To train the animal, the electrical stimulation must be sufficient to gain the animal's attention without injuring the animal. Further, some training protocols requires that the animal receive different stimulation based upon the animal's behavior. Various methods are known for varying the stimulation applied to an animal through a training collar. For example, U.S. Pat. No. 5,666,908, titled “Animal Training Device,” issued to So on Sep. 16, 1997, discloses an animal training device that applies different levels of electrical stimulation to an animal by varying a pulse width. The electrical stimulation is generated by applying a series of pulses to a switch connected to a transformer, which has its secondary windings connected to electrodes that contact the animal. The pulses have a constant voltage level at a fixed frequency; however, the pulse widths vary based on the desired stimulation to be applied. The transformer secondary voltage is directly related to the pulse width, accordingly, the electrical stimulation applied to the animal varies as the voltage varies. The lowest level of stimulation is produced with narrow pulse widths resulting in a lower voltage of electrical stimulation applied to the animal. The highest level of stimulation is produced with wide pulse widths resulting in higher voltage of electrical stimulation. Another example is the device disclosed in U.S. Pat. No. 4,802,482, titled “Method and Apparatus for Remote Control of Animal Training Stimulus,” issued to Gonda, et al., on Feb. 7, 1989. The Gonda device uses trains of pulses applied to the switch connected to the transformer. The Gonda device varies the stimulation intensity by varying the frequency of the pulses in the pulse train. The pulse train includes pulses having a fixed voltage and pulse width; however, the period between pulses is variable. The electrical stimulation applied to the animal is at a fixed voltage. The level of stimulation varies with the number of electrical stimulation signals applied to the animal per second. The lowest level of stimulation is produced by a pulse train with a low pulse frequency resulting in fewer electrical stimulation shocks per second. The highest level of stimulation is produced by a pulse train having a high pulse frequency resulting in more electrical stimulation shocks per second. The duration of the stimulation to the animal is controlled by the operator of the Gonda device. A still another example is the device disclosed in U.S. Pat. No. 5,054,428, titled “Method and Apparatus for Remote Conditioned Cue Control of Animal Training Stimulus,” issued to Farkus on Oct. 8, 1991. The Farkus device varies the stimulation intensity applied to the animal by varying the length of the pulse train applied to the switch connected to the transformer. The pulse train includes pulses having a fixed voltage and pulse width, and the pulses have a fixed frequency. The electrical stimulation applied to the animal is at a fixed voltage. The level of stimulation varies with the duration of the stimulation to the animal. The lowest level of stimulation is produced with a pulse train having a single pulse and a short duration. The highest level of stimulation is produced by a pulse train that includes approximately 64 pulses, which results in a longer duration stimulation being applied to the animal. BRIEF SUMMARY OF THE INVENTION According to one embodiment of the present invention, an animal training device is provided. The device includes a transmitter unit and a receiver unit, which is attached to a collar. The device provides a stimulus to an animal based on the actions of a trainer. The stimulus is either audible, such as a beep, or electrical, such as a shock applied to an external area of the animal. The electrical stimulation has variable levels determined by the voltage applied to a switch connected to a transformer, which is connected to electrodes. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which: FIG. 1 is a pictorial view of a transmitter unit and a receiver unit worn by an animal; FIG. 2 is a block diagram of one embodiment of the transmitter unit; FIG. 3 is a block diagram of one embodiment of the receiver unit; FIG. 4 is a partial schematic diagram showing one embodiment of a portion of the receiver unit; FIG. 5 is timing diagram for a low stimulation level; FIG. 6 is a timing diagram for a high stimulation level; and FIG. 7 is a flow diagram of one embodiment of the processor functions. DETAILED DESCRIPTION OF THE INVENTION An apparatus for an animal training device is disclosed. The device is shown generally as 10 on the drawings. The apparatus provides stimulation, either audible or electrical, to the animal to promote or discourage specific behavior of the animal. FIG. 1 illustrates the animal training device 10, which includes a transmitter unit 102 and a receiver unit 104 attached to a collar 106 worn by an animal 108. The transmitter unit 102 includes an antenna 118. Those skilled in the art will recognize that the antenna 118 can be an external antenna as shown in FIG. 1 or an antenna internal to the housing of the transmitter unit 102 without departing from the spirit and scope of the present invention. The transmitter unit 102 includes a pushbutton switch 112 for producing a tone at the receiver unit 104. The transmitter unit 102 also includes a pushbutton switch 114 for producing a corrective stimulation at the receiver unit 104. The transmitter unit 102 also includes a selector switch, or a stimulation level switch, 116 for selecting the level of correction. Those skilled in the art will recognize that the stimulation level switch 116 can be a rotary switch or other type of selector switch without departing from the spirit and scope of the present invention. The receiver unit 104 is attached to a collar 106 that is worn about the neck of an animal 108. Those skilled in the art will recognize that the collar 106 can be worn about other parts of the animal's body without departing from the spirit and scope of the present invention. FIG. 2 illustrates a block diagram of the transmitter unit 102. The tone switch 112, the correction switch 114, and the stimulation level switch 116 provide inputs to a processor 202. The processor 202 produces a signal that is sent through the transmitter 204 to the antenna 118. In one embodiment, pressing either the tone switch 112 or the correction switch 114 initiates the generation of a 14 bit data stream by the processor 202. The data stream generated by the processor 202 is sent to the transmitter 204 and, ultimately, the receiver unit 104. The 14 bit data stream includes 8 bits for an identification code, 1 bit to identify that data stream is a test or identification code, 1 bit to identify the stimulation type, that is, whether the stimulation is a beep (tone) or a shock (correction), and 4 bits for the stimulation level. The transmitter unit 102 is matched to the receiver unit 104 through the use of the identification code. Unless the identification code sent by the transmitter unit 102 matches the identification code stored in the receiver unit 104, the receiver unit 104 will not respond. The tenth bit, which identifies whether the stimulation is a tone or correction, is based on which switch, the tone switch 112 or the correction switch 114, is actuated. The final 4 bits are derived from the position of the stimulation level switch 116. In one embodiment, the stimulation level switch 116 is a 10-position rotary switch, with each position representing a different level of corrective stimulation. Those skilled in the art will recognize that the stimulation level switch 116 can have as many positions as stimulation levels desired without departing from the spirit and scope of the present invention. FIG. 3 illustrates a block diagram of the receiver unit 104. A receiving antenna 302 is connected to a receiver 304, which detects the signal from the transmitting unit 102 and outputs the 14 bit data stream as the received coded signal 322. The receiver 304 is connected to a processor 306, which acts upon the data stream. The processor 306 is connected to a switch 308, which controls the transformer 310 connected to the electrodes 312. The processor 306 is also connected to a speaker 314, which provides a tone to the animal. The 14 bit data stream is detected by the receiver 304 and is passed to the processor 306 as a received signal 322. The processor decodes the received signal, or data stream, 322 and controls the switch 308 and the speaker 314, as appropriate. In one embodiment, the speaker, or sound generating device, 314 includes an amplifier connected to a speaker or other sound producing device. The received signal 322 represents a request message from the transmitter unit 102, and the request message contains, in one embodiment, an identification code, a stimulation type code, and a stimulation level. In another embodiment, the received signal, or request message, 322 contains a test code that flags that the request message 322 is a test signal, in which case the processor 306 executes software that performs test functions. FIG. 4 is a schematic diagram of a portion of the receiver unit 104 showing only the relationship of the connections between the processor 306, the switch 308, and the transformer 310. The processor 306 has four output connections RB0, RB1, RB2, RB3 connected to the gate of single N-channel HEXFET power MOSFET Q4, which is the switch 308 illustrated in FIG. 3. The drain of the MOSFET Q4 is connected to the primary of the transformer 310. The other end of the primary of the transformer 310 is connected to the power supply V+. In one embodiment, the processor 306 is a Microchip part number PIC16F627, which is a CMOS FLASH-based 8-bit microcontroller. In one embodiment, the switch 308 is an International Rectifier part number IRLL110 or IRLD110 single N-channel HEXFET power MOSFET Q4. Those skilled in the art will recognize that other processors and switches can be used without departing from the scope and spirit of the present invention. The output connections RB0, RB1, RB2, RB3 of the controller 306 are bi-directional input/output (I/O) ports that can be programmed for internal weak pull-up. The output connections RB0, RB1, RB2, RB3 are controlled to be in one of three states: ground; Vdd, which is the positive power supply voltage; or a high impedance, which is the same as an open circuit. The four output connections RB0, RB1, RB2, RB3, in combination with voltage divider resistors R1, R2, R3, R4, control the voltage applied to the gate of the MOSFET Q4. For example, driving output RB3 to ground and the other outputs RB0, RB1, RB2 to a high impedance or ground state causes the gate of the MOSFET Q4 to be at the lowest possible voltage, ground, corresponding to a no stimulation level. Driving output RB3 to Vdd and the other outputs RB0, RB1, RB2 to a high impedance causes the gate of the MOSFET Q4 to be at the highest possible voltage, corresponding to a high stimulation level. The gate voltage is set between these two extremes by setting the state of the outputs RB0, RB1, RB2, RB3 such that the resistors R1, R2, R3, R4 provide a voltage divider. FIGS. 5 and 6 are timing diagrams illustrating the waveforms and their timing for the stimulation signals. The processor 306 produces, via the outputs RB0, RB1, RB2, RB3, output signals that pass through the voltage divider network R1, R2, R3, R4 resulting in an input pulse stream 512, 612 that is input to the gate of the MOSFET Q4. The input pulse stream 512, 612 has a fixed pulse width 502, a fixed pulse frequency (illustrated by the pulse width 502 and the separation 504 between pulses 512, 612), and a variable amplitude, or voltage level, 506, 606. The input pulse stream 512, 612 is acted upon by the switch 308 and transformer 310 to produce an output pulse stream 522, 622 having a fixed period 502 plus 504 or frequency. The amplitude, or voltage level, 508, 608 of the output pulse stream 522, 622 varies in relation to the selected stimulation level. With respect to FIG. 5, input signal 512 is the waveform for a low stimulation level signal entering the gate of MOSFET Q4 and output signal 522 is the waveform of the signal at the output of the transformer 310 corresponding to the input signal 512. The input signal 512 is a square wave signal with pulses 514 that have a voltage level 506, a width 502, and a period 504 between pulses. The secondary of the transformer 310 produces, or generates, an output signal 522, which is a pulse stream that corresponds to the input signal 512. When the input signal 512 transitions from the pulse 514 to the period 504 between pulses, an output pulse 524 is generated, and the output pulse 524 has a voltage level 508 corresponding to the voltage level 506 of the input signal 512. With respect to FIG. 6, input signal 612 is the waveform for a high stimulation level signal entering the gate of MOSFET Q4 and output signal 622 is the waveform of the signal at the output of the transformer 310 corresponding to the input signal 612. The output signal 622 voltage level 608 corresponds to the input signal 612 voltage level 606. Accordingly, as illustrated in FIGS. 5 and 6, the output signal 522, 622 voltage level 508, 608 is directly related to the input signal 512, 612 voltage level 506, 606. The input signal 512, 612 voltage level 506, 606 is controlled by the processor 306 and the resistors R1, R2, R3, R4, which form a voltage divider network based on the level of the processor 306 outputs RB0, RB1, RB2, RB3. The processor 306 includes software and routines for decoding the signal 322 received from the transmitting unit 102. Included in the coded signal 322 is a stimulation level code, which is used by the processor 306 to determine the setting of the outputs RB0, RB1, RB2, RB3. The outputs RB0, RB1, RB2, RB3 are controlled by the processor 306 to produce the input signal 512, 612 by alternating the state of the outputs RB0, RB1, RB2, RB3 between the pulse 514, 614 on and off states, with the on state being held for a period equal to the pulse width time 502 and the off state being held for a period equal to the period 504 between pulses 514, 614. FIG. 7 illustrates the various functions performed by one embodiment of the processor 306. The signals 322 from the receiver 304 are monitored 702. When a signal 322 is received, the signal 322 is checked to verify whether it contains a correct identification (ID) code 704. If the ID code matches that stored in the processor 306, the monitored signal 322 is then checked to see if the stimulation is a beep 708. If the ID code does not match, the signal 322 is ignored 706 and the processor 306 monitors the output of the receiver 304 for another signal 322. If the signal 322 indicates that a beep is desired, the processor 306 generates a beep 710, which operates the speaker 314. Generating the beep 710 is accomplished by generating a control signal that is routed to an output of the processor 306 that is connected to a sound generating device 314. If a beep is not desired, the monitored signal 322 is then checked to see if the stimulation is a shock 712. If the signal 322 does not indicate a shock is desired, the processor 306 loops back to monitor the output of the receiver 306. If a shock is desired, the signal 322 is decoded to generate the stimulation level 714. The processor 306 then generates stimulation level 714 by generating a control signal that is applied to the output connections RB0, RB1, RB2, RB3 of the controller 306, which are connected to the gate of the MOSFET Q4, either directly or through voltage divider resistors R1, R2, R3. The processor 306 controls the length of time the control signal is applied to the gate of the MOSFET Q4 (the pulse width 502) and the length of time between pulses 504. The length of the signal 322, which determines the stimulation period, is controlled by the operator operating the correction switch 114 and the processor 306. In one embodiment, the processor 306 includes a routine for limiting the duration of the signal 322. In one embodiment, this duration is a maximum of 8 seconds for all stimulation levels. In another embodiment, the operator can select a shorter stimulation period, or length of the signal 322, by releasing the correction switch 114 before the maximum duration time has been reached. For example, if the operator desires a one second stimulation, the operator depresses the correction switch 114 for a one second period and then releases the switch 114, which terminates the signal 322. The processor 306, in other embodiments, includes a routine for performing the function of verifying the validity of the received signal 322. As described above, the transmitter unit 102 generates a 14 bit data stream. In one embodiment, the processor 306 verifies that the received signal 322 contains exactly 14 bits of data. In one embodiment, each of the functions identified in FIG. 7 are performed by one or more software routines run by the processor 306. In another embodiment, one or more of the functions identified in FIG. 7 are performed by hardware and the remainder of the functions are performed by one or more software routines run by the processor 306. The processor 306 includes a memory medium that stores software, or routines, that the processor 306 executes. These routines can be discrete units of code or interrelated among themselves. Those skilled in the art will recognize that the various functions can be implemented as individual routines, or code snippets, or in various groupings without departing from the spirit and scope of the present invention. As used herein, software and routines are synonymous. However, in general, a routine refers to code that performs a specified function, whereas software is a more general term that may include more than one routine or perform more than one function. As used herein, the processor 306 should be broadly construed to mean any computer or component thereof that executes software. The processor 306 includes a memory medium that stores software, a processing unit that executes the software, and input/output (I/O) units for communicating with external devices. Those skilled in the art will recognize that the memory medium associated with the processor 306 can be either internal or external to the processing unit of the processor without departing from the scope and spirit of the present invention. The function of receiving the coded signal 322 is performed by the receiver 304. The function of decoding the coded signal 322 is performed by the processor 306. The function of producing the electrical stimulation is performed, in one embodiment, by the processor 306 outputting a pulse stream 512, 612 to a voltage divider to a switch 308, which is connected to the pulse transformer 310. The voltage produced through the voltage divider is related to the requested stimulation level. The function of producing a beep is performed by the processor 306 and the speaker 314. From the foregoing description, it will be recognized by those skilled in the art that an apparatus for an animal training device is provided. The apparatus uses an internal voltage level to control the voltage of the electrical stimulation applied to an animal for training. Also, the apparatus uses a processor to decode the signal from the transmitting unit and to control the stimulation type and level. While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant's general inventive concept. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of Invention This invention pertains to an apparatus for varying the intensity of stimulation applied during animal training. More particularly, this invention pertains to varying the intensity of stimulation applied to an animal wearing a collar having an attached receiver. The intensity is varied by controlling the voltage applied to a switching device that produces the shock pulses that provide the stimulation to the animal. 2. Description of the Related Art Radio controlled training collars are known for conditioning the behavior of an animal. A transmitter, commonly handheld, is controlled by a trainer. The collar is worn by an animal and includes a receiver that triggers an electrical circuit that applies electrical stimulation to the animal through electrodes in contact with the animal. To train the animal, the electrical stimulation must be sufficient to gain the animal's attention without injuring the animal. Further, some training protocols requires that the animal receive different stimulation based upon the animal's behavior. Various methods are known for varying the stimulation applied to an animal through a training collar. For example, U.S. Pat. No. 5,666,908, titled “Animal Training Device,” issued to So on Sep. 16, 1997, discloses an animal training device that applies different levels of electrical stimulation to an animal by varying a pulse width. The electrical stimulation is generated by applying a series of pulses to a switch connected to a transformer, which has its secondary windings connected to electrodes that contact the animal. The pulses have a constant voltage level at a fixed frequency; however, the pulse widths vary based on the desired stimulation to be applied. The transformer secondary voltage is directly related to the pulse width, accordingly, the electrical stimulation applied to the animal varies as the voltage varies. The lowest level of stimulation is produced with narrow pulse widths resulting in a lower voltage of electrical stimulation applied to the animal. The highest level of stimulation is produced with wide pulse widths resulting in higher voltage of electrical stimulation. Another example is the device disclosed in U.S. Pat. No. 4,802,482, titled “Method and Apparatus for Remote Control of Animal Training Stimulus,” issued to Gonda, et al., on Feb. 7, 1989. The Gonda device uses trains of pulses applied to the switch connected to the transformer. The Gonda device varies the stimulation intensity by varying the frequency of the pulses in the pulse train. The pulse train includes pulses having a fixed voltage and pulse width; however, the period between pulses is variable. The electrical stimulation applied to the animal is at a fixed voltage. The level of stimulation varies with the number of electrical stimulation signals applied to the animal per second. The lowest level of stimulation is produced by a pulse train with a low pulse frequency resulting in fewer electrical stimulation shocks per second. The highest level of stimulation is produced by a pulse train having a high pulse frequency resulting in more electrical stimulation shocks per second. The duration of the stimulation to the animal is controlled by the operator of the Gonda device. A still another example is the device disclosed in U.S. Pat. No. 5,054,428, titled “Method and Apparatus for Remote Conditioned Cue Control of Animal Training Stimulus,” issued to Farkus on Oct. 8, 1991. The Farkus device varies the stimulation intensity applied to the animal by varying the length of the pulse train applied to the switch connected to the transformer. The pulse train includes pulses having a fixed voltage and pulse width, and the pulses have a fixed frequency. The electrical stimulation applied to the animal is at a fixed voltage. The level of stimulation varies with the duration of the stimulation to the animal. The lowest level of stimulation is produced with a pulse train having a single pulse and a short duration. The highest level of stimulation is produced by a pulse train that includes approximately 64 pulses, which results in a longer duration stimulation being applied to the animal. | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>According to one embodiment of the present invention, an animal training device is provided. The device includes a transmitter unit and a receiver unit, which is attached to a collar. The device provides a stimulus to an animal based on the actions of a trainer. The stimulus is either audible, such as a beep, or electrical, such as a shock applied to an external area of the animal. The electrical stimulation has variable levels determined by the voltage applied to a switch connected to a transformer, which is connected to electrodes. | 20040402 | 20060926 | 20051006 | 75849.0 | 1 | BERONA, KIMBERLY SUE | INTENSITY VARIATION DEVICE FOR TRAINING ANIMALS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,817,679 | ACCEPTED | Salmon egg chain | This invention is a fishing device that is used in its preferred embodiment to attract fish to an object. The invention comprises an untold number of similar features that are mounted to the structure of a strand. When fastened into a loop, the similar features on the strand in the preferred embodiment attract fish. | 1-13. (canceled) 14. A fishing device comprising a fibrous strand, and also comprises a plurality of beads that are joined to said strand by a fixing means. 15. The device in claim 14 wherein said fixing means employs a molding process, in such a way that said strand and said beads exist together as a contiguous form of material. 16. A method of fishing that comprises the act of fixing a fibrous strand to a plurality of beads, thus making a contiguous form of material. 17. The method in claim 16 wherein said act of fixing said strand to said beads employs a molding process. | BACKGROUND This invention relates to fishing. Several kinds of live bait are used to hook fish. In addition, many kinds of manmade luring devices (lures) are commercially avaible for sport and subsistence fishing. Most of these lures are designed to mimic particular traits of the organisms that constitute the natural diet of fish. Such traits may relate to appearance, odor, visual reflection, or physical behavior. Many lures are designed to simulate two or more of these traits, in combination. There are also additives, such as oils, which are used to provide lures with odors that have been proven to attract fish. Actual fish eggs (specifically salmon eggs) are part of the natural diet of several kinds of freshwater fish. Fertilized salmon eggs are naturally found in the gravel beds in freshwater streams and rivers, in large groups of several hundred. Salmon eggs are fertilized by the milt of the male, immediately after being deposited by the female. Because the milt is a dense milky fluid, fertilized eggs often appear under a boundary of cloudy water. It is thought that cloudy water in clear streams indicates the presence of salmon eggs, as well as a temporarily abundant supply of nutrient-rich food for predators. Thus, it is no surprise that synthetic salmon eggs are widely used in fishing, and successful in attracting many kinds of freshwater fish. Synthetic salmon eggs are sold commercially, in molded clumps. These synthetic eggs are also available with an oil coating that releases an attractive odor into the water. However, these clumps do not provide the appearance of localized cloudy water. Subsistence fishermen would benefit from salmon egg lures that also provide a proximity of cloudy water. To mimic the appearance of cloudy water, outfitters produce strands of yarn, or bundles of other fibrous materials, to be sold as lures. These yarn strands contain many fibers, which can be fluffed-out manually. When immersed in water, these fluffed bundles give the water a cloudy appearance. They are sold seperately, and require their own process of being fastened to fishing lines. The object of this invention is to provide a single lure, which mimics salmon eggs, and which also simulates a cloudy water environment. The benefit is that a single lure, with the attractive quality of several existing lures combined, is much easier to fasten to a fishing line. This increases the yield for subsistence fishermen, and sport fisherman alike. SUMMARY In accordance with this invention, the device is a string of continuous material. It comprises a number of repetitive node features that are regularly spaced along its length. These node features are somewhat spherical in shape. Between each node feature is a linking segment of constant cross-section. The device can be used as a whole, or it can be used to supply several useful cut lengths, which perform the same function. In the preferred embodiment, the device comprises a row of gummy beads, which are evenly spaced. A single length of yarn runs along through each bead, connecting it to others and forming a chain. The yarn is flexible and fibrous. Between nodes, the yarn can be fluffed to create the appearance of cloudy water. The yarn also allows the device to be tied into a loop. Said loop can be securely fastened to a fishing line, to serve as a very effective lure. The preferred embodiment of this invention is used as fishing bait to attract waterlife to a catching means, such as a hook or a trap. The function of this invention encompasses any applicable use of the device to attract fish. However, the preferred embodiment teaches taking a cut length of the device, tying it into a loop, and securing it to a fish hook. REFERENCE TO DRAWINGS Drawing Figures FIG. 1 shows the preferred embodiment of the invention in the open position, in perspective. FIG. 2 shows a partial assembly of the preferred embodiment of the invention temporarily containing a needle, in perspective. REFERENCE NUMERALS IN DRAWINGS 10 Bead 20 Strand 30 Chain 40 Needle DETAILED DESCRIPTION The preferred embodiment of the invention is shown in FIG. 1. This embodiment comprises a uniform distribution of beads 10 along a single strand 20 of yarn. The beads remain in a fixed position on the strand, using a suitable fixing means. This embodiment also comprises a length of excess yarn at each end, for making a suitable knot to be used in the formation of a loop. In this embodiment, said fixing means is friction. Some other suitable fixing means may include the use of adhesives, co-molding processes, and knottings along the strand. Together, the strand and the beads are referred to as a chain 30. The chain can be opened, or it can be closed (as in a loop). The chain may be attached, somewhere along its length, to some other object, by an appropriate fastening means. When the chain is attached to some other object, such as a fishing line, it can perform its intended function. When used in water, with the intended function of the preferred embodiment, the invention will attract fish. During use, the invention is held underwater at a desired location. While underwater, the invention may be moved, so as to lead fish to another location. In the preferred embodiment, the beads are molded. The molded material is plastic. The beads can also be of some other material that is suitable for providing friction upon assembly, while said material remains pliable. In the preferred embodiment, the strand comprises a length of yarn. The strand may also comprise a body of fibrous material that lends itself to automated production, or to material simplicity. The invention may either be comprised of separate elements, or made as a single molded piece of appropriate material. Both of which are contiguous embodiments of the eventual shape. FIG. 2 shows a typical chain 30 during manual assembly. A needle 40 has been threaded with a strand of yarn, and used further to thread a plurality of beads. | <SOH> BACKGROUND <EOH>This invention relates to fishing. Several kinds of live bait are used to hook fish. In addition, many kinds of manmade luring devices (lures) are commercially avaible for sport and subsistence fishing. Most of these lures are designed to mimic particular traits of the organisms that constitute the natural diet of fish. Such traits may relate to appearance, odor, visual reflection, or physical behavior. Many lures are designed to simulate two or more of these traits, in combination. There are also additives, such as oils, which are used to provide lures with odors that have been proven to attract fish. Actual fish eggs (specifically salmon eggs) are part of the natural diet of several kinds of freshwater fish. Fertilized salmon eggs are naturally found in the gravel beds in freshwater streams and rivers, in large groups of several hundred. Salmon eggs are fertilized by the milt of the male, immediately after being deposited by the female. Because the milt is a dense milky fluid, fertilized eggs often appear under a boundary of cloudy water. It is thought that cloudy water in clear streams indicates the presence of salmon eggs, as well as a temporarily abundant supply of nutrient-rich food for predators. Thus, it is no surprise that synthetic salmon eggs are widely used in fishing, and successful in attracting many kinds of freshwater fish. Synthetic salmon eggs are sold commercially, in molded clumps. These synthetic eggs are also available with an oil coating that releases an attractive odor into the water. However, these clumps do not provide the appearance of localized cloudy water. Subsistence fishermen would benefit from salmon egg lures that also provide a proximity of cloudy water. To mimic the appearance of cloudy water, outfitters produce strands of yarn, or bundles of other fibrous materials, to be sold as lures. These yarn strands contain many fibers, which can be fluffed-out manually. When immersed in water, these fluffed bundles give the water a cloudy appearance. They are sold seperately, and require their own process of being fastened to fishing lines. The object of this invention is to provide a single lure, which mimics salmon eggs, and which also simulates a cloudy water environment. The benefit is that a single lure, with the attractive quality of several existing lures combined, is much easier to fasten to a fishing line. This increases the yield for subsistence fishermen, and sport fisherman alike. | <SOH> SUMMARY <EOH>In accordance with this invention, the device is a string of continuous material. It comprises a number of repetitive node features that are regularly spaced along its length. These node features are somewhat spherical in shape. Between each node feature is a linking segment of constant cross-section. The device can be used as a whole, or it can be used to supply several useful cut lengths, which perform the same function. In the preferred embodiment, the device comprises a row of gummy beads, which are evenly spaced. A single length of yarn runs along through each bead, connecting it to others and forming a chain. The yarn is flexible and fibrous. Between nodes, the yarn can be fluffed to create the appearance of cloudy water. The yarn also allows the device to be tied into a loop. Said loop can be securely fastened to a fishing line, to serve as a very effective lure. The preferred embodiment of this invention is used as fishing bait to attract waterlife to a catching means, such as a hook or a trap. The function of this invention encompasses any applicable use of the device to attract fish. However, the preferred embodiment teaches taking a cut length of the device, tying it into a loop, and securing it to a fish hook. | 20040401 | 20070213 | 20051013 | 69768.0 | 0 | HAYES, BRET C | SALMON EGG CHAIN | SMALL | 0 | ACCEPTED | 2,004 |
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10,817,817 | ACCEPTED | Semiconductor integrated circuit and method of designing the same | According to the present invention, a semiconductor integrated circuit having: a cell region in which a plurality of MOS transistors forming at least one cell are placed; and first and second power lines placed along one direction in a peripheral portion of the cell region, wherein in the cell region, gate grids for defining a first pitch in the one direction and pin grids for defining a second pitch in the one direction are set, gate electrodes of the MOS transistors are placed in accordance with the gate grids, and an interconnection layer is placed in accordance with the pin grids. | 1. A semiconductor integrated circuit comprising: a cell region in which a plurality of MOS transistors forming at least one cell are placed; and first and second power lines placed along one direction in a peripheral portion of said cell region, wherein in said cell region, gate grids configured to define a first pitch in said one direction and pin grids for defining a second pitch in said one direction are set, gate electrodes of said MOS transistors are placed in accordance with the gate grids, and an interconnection layer is placed in accordance with the pin grids. 2. A circuit according to claim 1, further comprising an input/output terminal connected to the gate electrode of said MOS transistor, wherein if a gate grid at which the gate electrode is positioned is not aligned with the pin grids, said input/output terminal is placed so as to extend over the gate grid and one of the pin grids adjacent to the gate grid. 3. A circuit according to claim 2, wherein in said cell region, an impurity diffusion layer configured to fix a potential of a well in said cell region is placed. 4. A circuit according to claim 3, wherein said impurity diffusion layer is connected to said first or second power line. 5. A circuit according to claim 1, wherein in said cell region, an impurity diffusion layer configured to fix a potential of a well in said cell region is placed. 6. A circuit according to claim 1, wherein said impurity diffusion layer is connected to said first or second power line. 7. A circuit according to claim 1, further comprising third and fourth power lines having a potential different from said first and second power lines, wherein said impurity diffusion layer is connected to said third or fourth power line. 8. A circuit according to claim 1, wherein at least two cells are placed in said cell region, and a dummy gate is placed between the cells. 9. A circuit according to claim 1, wherein in said cell region, second pin grids configured to define a third pitch in another direction perpendicular to said one direction are set, and the circuit further comprises another interconnection layer placed in accordance with the second pin grids. 10. A method of designing a semiconductor integrated circuit, comprising: providing a cell region in which a plurality of MOS transistors forming at least one cell are placed, setting gate grids for defining a first pitch in one direction and pin grids for defining a second pitch in the one direction; placing first and second power lines along the one direction in a peripheral portion of the cell region; placing the MOS transistors such that gate electrodes are positioned on the gate grids; and placing an interconnection layer in accordance with the pin grids. 11. A method according to claim 10, further comprising, placing an input/output terminal to be connected to the gate electrode of the MOS transistor such that, if a gate grid at which the gate electrode is positioned is not aligned with the pin grids, the input/output terminal is placed so as to extend over the gate grid and one of the pin grids adjacent to the gate grid. 12. A method according to claim 10, further comprising, placing, in the cell region, an impurity diffusion layer for fixing a potential of a well in the cell region. 13. A method according to claim 10, wherein the impurity diffusion layer is connected to the first or second power line when placed. 14. A method according to claim 10, further comprising, placing third and fourth power lines having a potential different from the first and second power lines, wherein the impurity diffusion layer is connected to the third or fourth power line. 15. A method according to claim 10, wherein when at least two cells are placed in the cell region, and the method further comprises, placing a dummy gate between the cells. 16. A method according to claim 10, further comprising: setting, in the cell region, second pin grids for defining a third pitch in another direction perpendicular to the one direction; and placing another interconnection layer in accordance with the second pin grids. | CROSS REFERENCE TO RELATED APPLICATION This application is based upon and claims benefit of priority under 35 USC 119 from the Japanese Patent Application No. 2003-136135, filed on May 14, 2003, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION The present invention relates to a semiconductor integrated circuit and a method of designing the same and, more particularly, to a semiconductor integrated circuit suited to laying out standard cells. Recently, the circuit scale of semiconductor integrated circuits is abruptly increasing, and demands for shortening the development time are also increasing. Accordingly, a method has been extensively used which does not cause a circuit designer to plan and design a circuit configuration for realizing logic by himself or herself, but designs a circuit block for implementing a desired function by performing logic synthesis, placement, and routing by using software for performing logic synthesis. In designing circuit blocks forming a semiconductor device as described above, a standard cell is used to perform logic synthesis and implement the circuit blocks by using software on the basis of functionally described design data. A standard cell is a small-scale circuit (to be referred to as a cell hereinafter) preformed to realize basic logic, and prepared for each of a plurality of types of logic. In addition, even for single logic, a plurality of cells having different load driving forces, i.e., different sizes are prepared to control various loads. A set of a plurality of types of cells is called a standard cell library. FIG. 7 is a plan view showing a conventional standard cell layout. In a surface portion of a semiconductor substrate, an N-type well region N1 and P-type well region P1 are placed. In the N-type well region N1, a gate electrode GE1 is formed on the substrate. On the two sides of the gate electrode GE1, a P-type impurity is ion-implanted to form P-type diffusion layers, thereby forming a PMOS transistor PM1. In the P-type diffusion layers, a source electrode SE1 is formed on a source region, and a drain electrode DE1 is formed on a drain region. Likewise, in the P-type well region P1, the gate electrode GE1 is so formed as to extend, and an N-type impurity is ion-implanted on the two sides of the gate electrode GE1 to form N-type diffusion layers, thereby forming an NMOS transistor NM1. In the N-type diffusion layers, a source electrode SE2 is formed on a source region, and a drain electrode DE1 is formed on a drain region. An N-type diffusion layer NS1 for fixing the substrate bias potential is placed in the end portion of the N-type well region N1, and a metal interconnection MW1 is placed around the N-type diffusion layer NS1. A P-type diffusion layer PS1 for fixing the substrate bias potential is placed in the end portion of the P-type well region P1, and a metal interconnection MW2 is placed around the P-type diffusion layer PS1. The source electrode SE1 is connected to the metal interconnection MW1, and the source electrode SE2 is connected to the metal interconnection MW2. In the conventional device as described above, the diffusion layers and metal interconnections for applying the substrate bias potential to the P- and N-type wells formed in the surface of the semiconductor substrate are placed in a standard cell. As these diffusion layers for fixing the substrate bias, impurities are ion-implanted by using masks to form the N-type diffusion layer NS1 in the N-type well and the P-type diffusion layer PS1 in the P-type well. As micropatterning progresses, however, it is found that the design rule for impurity ion implantation makes micropatterning difficult to perform, compared to the design rule for MOS transistor formation and metal interconnection. This makes it difficult to decrease a width d11 of the power lines MW1 and MW2 so formed as to surround the N- and P-type diffusion layers NS1 and PS1, respectively, shown in FIG. 7, thereby failing further micropatterning. In addition, pin grids which define the pitch of metal interconnections is conventionally used as a reference for laying out cells and metal interconnections. FIG. 8 shows the pitch of metal pins MP as a pin grid pitch MGP. Unfortunately, pin grids are not suited to the cell layout, so intervals between a gate electrode GE11 of a P-channel MOS transistor PM11 and N-channel MOS transistor NM11, a gate electrode GE12 of a P-channel MOS transistor PM12 and N-channel MOS transistor NM12, and a gate electrode GE13 of a P-channel MOS transistor PM13 and N-channel MOS transistor NM13 do not match the pin grids. In fact, the layout is random. Consequently, as shown in FIG. 9, intervals between the gate electrodes of MOS transistors placed in the upper and lower portions are different from each other. More specifically, intervals between a gate electrode GE21 of a P-channel MOS transistor PM21 and N-channel MOS transistor NM21, a gate electrode GE22 of a P-channel MOS transistor PM22 and N-channel MOS transistor NM22, and a gate electrode GE23 of a P-channel MOS transistor PM23 and N-channel MOS transistor NM23 placed in the upper portion are different from intervals between a gate electrode GE24 of an N-channel MOS transistor NM24 and P-channel MOS transistor PM24, a gate electrode GE25 of an N-channel MOS transistor NM25 and P-channel MOS transistor PM25, a gate electrode GE26 of an N-channel MOS transistor NM26 and P-channel MOS transistor PM26, and a gate electrode GE27 of an N-channel MOS transistor NM27 and P-channel MOS transistor PM27 placed in the lower portion. This layout difference between the gate electrodes of the upper and lower transistors poses the following problems. Presently, in patterning the gate electrodes of MOS transistors by using a photomask, the phase of exposure light is shifted to increase the degree of micropatterning. Under the circumstances, if the gate electrodes of the upper and lower transistors are placed at irregular intervals as shown in FIG. 9, the degree of micropatterning is largely limited by the design rule. FIG. 10 shows a diffusion layer D1 and gate electrodes G1 and G2 of transistors placed in the upper portion, and a diffusion layer D2 and gate electrode G3 of a transistor placed in the lower portion. Mask patterns MP1, MP2, and MP3 are placed in the upper portion as photomasks for patterning the upper gate electrodes G1 and G2. Mask patterns MP4 and MP5 are placed as photomasks for patterning the lower gate electrode G3. The positions of the upper gate electrodes G1 and G2 and the lower gate electrode G3 are different from each other. Assuming that the first phase of exposure light comes in contact with the end face of the upper mask pattern MP1, the second phase comes in contact with the mask pattern MP2 adjacent to the mask pattern MP1, and the first phase comes in contact with the mask pattern MP3 adjacent to the mask pattern MP2. To pattern gate electrodes, therefore, different phases of light must come in contact with adjacent mask patterns. Unfortunately, the lower mask patterns MP4 and MP5 are positioned between the upper mask patterns MP1 and MP3, so the second phase of light comes in contact with both of these lower mask patterns. This makes patterning impossible. A difference between the upper and lower mask patterns produces this phase contradiction. To prevent this phase contradiction, it is necessary to increase the spacings between the upper mask patterns MP1, MP2, and MP3 and between the lower mask patterns MP4 and MP5, and this increases the cell size. References disclosing semiconductor integrated circuits using the conventional standard cell are as follows. Japanese Patent Laid-Open No. 10-154756 Japanese Patent Laid-Open No. 2001-168291 Japanese Patent Laid-Open No. 2000-22084 As described above, a region for supplying the substrate potential conventionally interferes with micropatterning. In addition, although the cell placement is based on pin grids, the placement of the gate electrodes of MOS transistors is irregular. As a consequence, the cell area increases by large limitations on the design rules. SUMMARY OF THE INVENTION According to one aspect of the present invention, there is provided a semiconductor integrated circuit comprising: a cell region in which a plurality of MOS transistors forming at least one cell are placed; and first and second power lines placed along one direction in a peripheral portion of said cell region, wherein in said cell region, gate grids configured to define a first pitch in said one direction and pin grids for defining a second pitch in said one direction are set, gate electrodes of said MOS transistors are placed in accordance with the gate grids, and an interconnection layer is placed in accordance with the pin grids. According to one aspect of the present invention, there is provided a method of designing a semiconductor integrated circuit, comprising: providing a cell region in which a plurality of MOS transistors forming at least one cell are placed, setting gate grids for defining a first pitch in one direction and pin grids for defining a second pitch in the one direction; placing first and second power lines along the one direction in a peripheral portion of the cell region; placing the MOS transistors such that gate electrodes are positioned on the gate grids; and placing an interconnection layer in accordance with the pin grids. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing the arrangement of a semiconductor integrated circuit according to the first embodiment of the present invention; FIG. 2 is a plan view showing the arrangement of a semiconductor integrated circuit according to the second embodiment of the present invention; FIG. 3 is a plan view showing the arrangement of a semiconductor integrated circuit according to the third embodiment of the present invention; FIG. 4 is a plan view showing the arrangement of a semiconductor integrated circuit according to the fourth embodiment of the present invention; FIG. 5 is a plan view showing the arrangement of the fifth embodiment of the present invention, in which a substrate potential different from a power supply voltage Vdd is applied to an N-type well, and a substrate potential different from a ground voltage Vss is applied to a P-type well; FIG. 6 is a plan view showing the arrangement of the sixth embodiment of the present invention, in which metal interconnections are placed in the third layer; FIG. 7 is a plan view showing the arrangement of a conventional semiconductor integrated circuit; FIG. 8 is a plan view showing the arrangement of another conventional semiconductor integrated circuit; FIG. 9 is a plan view showing the arrangement of still another conventional semiconductor integrated circuit; and FIG. 10 is a plan view for explaining the problem of phase contradiction in the conventional semiconductor integrated circuit. DESCRIPTION OF THE EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. (1) First Embodiment FIG. 1 is a plan view showing the arrangement of a semiconductor integrated circuit according to this embodiment. An N-type well region N101 and P-type well region P101 are placed in a surface portion of a semiconductor substrate. A power supply voltage Vdd line VD101 and ground voltage Vss line VS101 are placed above and below, respectively, in FIG. 1, the pair of the N-type well region N101 and P-type well region P101. In the vertical direction of FIG. 1, pin grids as a reference of a metal pin pitch are indicated by the alternate long and short dashed lines, and gate grids as a reference of the pitch of the gate electrodes of MOS transistors are indicated by the dotted lines. In this embodiment, the ratio of the pin grid pitch to the gate grid pitch is set at 2:3. In the N-type well region N101, a gate electrode GE101 is formed on the substrate, and a P-type impurity is ion-implanted on the two sides of this gate electrode to form P-type diffusion layers, thereby forming a PMOS transistor PM101. Similarly, in the N-type well region N101, gate electrodes GE102 and GE103 are formed, and a P-type impurity is ion-implanted on the two sides of each of these gate electrodes to form P-type diffusion layers, thereby forming PMOS transistors PM102 and PM103. A source electrode for connecting a source region in the P-type diffusion layers and the power supply voltage Vdd terminal VD101, a source electrode for connecting a source region in N-type diffusion layers (to be described later) and the ground voltage, and a drain electrode for connecting a drain region in the P-type diffusion layers and a drain region in the N-type diffusion layers are not illustrated in FIG. 1. In the P-type well region P101, the gate electrode GE101 is so formed as to extend, and an N-type impurity is ion-implanted on the two sides of this gate electrode to form N-type diffusion layers, thereby forming an NMOS transistor NM101. In addition, in the P-type well region P101, the gate electrodes GE102 and GE103 are so formed as to extend, and N-type diffusion layers are formed on the two sides of each of these gate electrodes, thereby forming NMOS transistors NM102 and NM103. On the boundary line between the N-type well region N101 and P-type well region P101, a metal terminal is formed as an input/output terminal I/O101 so as to be connected to the gate electrode GE101. Likewise, on the boundary line between the N-type well region N101 and P-type well region P101, metal terminals are formed as input/output terminals I/O102 and I/O103 so as to be connected to the gate electrodes GE102 and GE103, respectively. As described above, the first characteristic feature of this embodiment is that the MOS transistors PM101 to PM103 and NM101 to NM103 forming the circuit are normalized when they are placed such that the gate electrodes GE101 to GE103 are placed on the gate grids. By this normalization, it is possible to eliminate the problems concerning, e.g., the processing accuracy in the photomasks, lithography step, and etching step, resulting from the nonuniformity of the conventional gate electrode placement, and to improve the degree of integration. The second characteristic feature of this embodiment is that the input/output terminals I/O101 to I/O103 formed between the plurality of MOS transistors are placed by taking account of differences between the gate grids and pin grids. More specifically, the gate electrode GE101 is placed on a gate grid but is not placed on a pin grid. In this case, the input/output terminal I/O101 connected to the gate electrode GE101 is so placed as to extend over the gate grid on which the gate electrode GE101 is placed and one of two pin grids closest to this gate grid. In this embodiment, therefore, MOS transistors and input/output terminals can be regularly placed. This helps reduce the element area by preventing the formation of an unnecessary element area. (2) Second Embodiment FIG. 2 is a plan view showing the arrangement of a semiconductor integrated circuit according to this embodiment. This embodiment is characterized in that two adjacent cells are placed, and impurity diffusion layers are additionally placed as cells for setting the substrate potential. An N-type well region N111 and P-type well region P111 are placed in a surface portion of a semiconductor substrate. A power supply voltage Vdd line VD111 and ground voltage Vss line VS111 are placed above and below, respectively, in FIG. 2, the pair of the N-type well region N111 and P-type well region P111. As in the first embodiment described above, in the vertical direction of FIG. 2, pin grids as a reference of a metal pin pitch are indicated by the alternate long and short dashed lines, and gate grids as a reference of the pitch of the gate electrodes of MOS transistors are indicated by the dotted lines. In this embodiment, as in the above embodiment, the ratio of the pin grid pitch to the gate grid pitch is set at 2:3. In the N-type well region N111, a gate electrode GE111 is formed on the substrate, and P-type diffusion layers are formed on the two sides of this gate electrode to form a PMOS transistor PM111. Similarly, gate electrodes GE112, GE113, and GE114 are formed, and P-type diffusion layers are formed on the two sides of each of these gate electrodes to form PMOS transistors PM112, PM113, and PM114, respectively. In the P-type well region P111, the gate electrodes GE111, GE112, GE113, and GE114 are so formed as to extend, and N-type diffusion layers are formed on the two sides of each of these gate electrodes to form NMOS transistors NM111, NM112, NM113, and NM114, respectively. In this arrangement, a cell made up of the PMOS transistor PM114 and NMOS transistor NM114 is formed adjacent to cells made up of the PMOS transistor PM111 and NMOS transistor NM111, the PMOS transistor PM112 and NMOS transistor NM112, and the PMOS transistor PM113 and NMOS transistor NM113. On the boundary line between the N-type well region N111 and P-type well region P111, input/output terminals I/O111 to I/O114 are so formed as to be connected to the gate electrodes GE111 to GE114, respectively. In addition, in this embodiment, a substrate potential supply cell for applying a power supply voltage Vdd to the N-type well N111 and a ground voltage Vss to the P-type well P111 is formed in the same cell region as the MOS transistors. That is, an N-type impurity diffusion layer NS111 is placed in the N-type well 111 and electrically connected to the power supply voltage Vdd line VD111. Likewise, a P-type impurity diffusion layer PS111 is placed in the P-type well 111 and electrically connected to the ground voltage Vss line VS111. Similar to the first embodiment described above, the first characteristic feature of this embodiment is that the MOS transistors PM111 to PM114 and NM111 to NM114 forming the circuit are normalized when they are placed such that the gate electrodes GE111 to GE114 are placed on the gate grids. The second characteristic feature of this embodiment is that the input/output terminals I/O111 to I/O114 formed between the plurality of MOS transistors are placed by taking account of differences between the gate grids and pin grids. More specifically, the gate electrode GE111 is placed on a gate grid but is not placed on a pin grid. In this case, the input/output terminal I/O111 connected to the gate electrode GE111 is so placed as to extend over the gate grid on which the gate electrode GE111 is placed and one of two pin grids closest to this gate grid. In this embodiment, therefore, MOS transistors and input/output terminals can be regularly placed. This helps reduce the element area by preventing the formation of an unnecessary element area. Furthermore, the third characteristic feature of this embodiment is that the diffusion layers NS111 and PS111 for applying the substrate bias potential to the N-type well N111 and P-type well P111 are formed as substrate potential setting cells in the region in which the MOS transistors are placed. Conventionally, as explained earlier with reference to FIG. 7, the diffusion layer NS1 is formed in the power supply voltage Vdd line MW1 to apply the power supply voltage Vdd to the N-type well N1, and the diffusion layer PS1 is formed in the ground voltage Vss line MW2 to apply the ground voltage Vss to the P-type well P1. This makes it impossible to reduce the width d11 of the power supply voltage Vdd line MW1 and ground voltage Vss line MW2, thereby preventing micropatterning. In contrast, in this embodiment, since such impurity diffusion layers for applying the substrate potential need not be formed in the power supply voltage Vdd line VD111 and ground voltage Vss line VS111, the width d1 can be made smaller than the conventional width d11, and this contributes to micropatterning of elements. (3) Third Embodiment FIG. 3 is a plan view showing the arrangement of a semiconductor integrated circuit according to this embodiment. An N-type well region N121 and P-type well region P121 are placed in a surface portion of a semiconductor substrate. A power supply voltage Vdd line VD121 and ground voltage Vss line VS121 are placed above and below, respectively, in FIG. 3, the pair of the N-type well region N121 and P-type well region P121. Another pair of a P-type well region P122 and N-type well region N122 are symmetrically placed with respect to the ground voltage Vss line VS121. A power supply voltage Vdd line VD122 is placed below, in FIG. 3, the N-type well region N122. As in the first and second embodiments described above, pin grids as a reference of a metal pin pitch are indicated by the alternate long and short dashed lines, and gate grids as a reference of the pitch of the gate electrodes of MOS transistors are indicated by the dotted lines. The ratio of the pin grid pitch to the gate grid pitch is set at 2:3. In the N-type well region N121, gate electrodes GE121, GE122, GE123, and GE124 are formed, and P-type diffusion layers are formed on the two sides of each of these gate electrodes to form PMOS transistors PM121, PM122, PM123, and PM124, respectively. In the P-type well region P121, the gate electrodes GE121, GE122, GE123, and GE124 are so formed as to extend, and N-type diffusion layers are formed on the two sides of each of these gate electrodes to form NMOS transistors NM121, NM122, NM123, and NM124, respectively. On the boundary line between the N-type well region N121 and P-type well region P121, input/output terminals I/O121 to I/O124 are so formed as to be connected to the gate electrodes GE121 to GE124, respectively. Likewise, in the P-type well region P122, gate electrodes GE125 to GE128 are formed, and N-type diffusion layers are formed on the two sides of each of these gate electrodes to form NMOS transistors NM125 to NM128, respectively. In the N-type well region N122, the gate electrodes GE125 to GE128 are so formed as to extend, and P-type diffusion layers are formed on the two sides of each of these gate electrodes to form PMOS transistors PM125 to PM128, respectively. On the boundary line between the N-type well region N122 and P-type well region P122, input/output terminals I/O125 to I/O128 are so formed as to be connected to the gate electrodes GE125 to GE128, respectively. Furthermore, as in the second embodiment described above, N-type impurity diffusion layers NS121 and NS122 for applying a power supply voltage Vdd to the N-type wells N121 and N122 and P-type impurity diffusion layers PS121 and PS122 for applying a ground voltage Vss to the P-type wells P121 and P122 are formed in the same cell region as the MOS transistors. Similar to the first and second embodiments described above, the first characteristic feature of this embodiment is that the MOS transistors PM121 to PM128 and NM121 to NM128 forming the circuit are normalized when they are placed such that the gate electrodes GE121 to GE128 are placed on the gate grids. This prevents differences between the gate electrodes of these MOS transistors placed in the vertical direction of FIG. 3. This eliminates the problem of phase contradiction which has conventionally occurred due to differences between the layouts of the gate electrodes of upper and lower MOS transistors when patterning is performed using photomasks. Accordingly, unlike in the conventional circuit, it is no longer necessary to place upper and lower MOS transistors with spacings between them by taking account of the phase contradiction. This realizes micropatterning. Similar to the first and second embodiments described previously, the second characteristic feature of this embodiment is that the input/output terminals I/O121 to I/O128 formed between the plurality of MOS transistors are placed by taking account of differences between the gate grids and pin grids. Furthermore, as in the second embodiment, the third characteristic feature of this embodiment is that the diffusion layers NS121, NS122, PS121, and PS122 for applying the substrate bias potential to the N-type wells N121 and N122 and the P-type wells P121 and P122 are formed as substrate potential setting cells in the region in which the MOS transistors are placed. This obviates the need to form any impurity diffusion layers for applying the substrate potential in the power supply voltage Vdd line VD121 and ground voltage Vss line VS121. Consequently, the width d1 can be made smaller than the conventional width d11, so micropatterning of elements is realized. (4) Fourth Embodiment The fourth embodiment of the present invention will be described below with reference to FIG. 4. This embodiment includes dummy gates between cells in addition to the arrangement of the third embodiment described above. An N-type well region N141 and P-type well region P141 are placed in a surface portion of a semiconductor substrate. A power supply voltage Vdd line VD141 and ground voltage Vss line VS141 are placed above and below, respectively, in FIG. 4, the pair of the N-type well region N141 and P-type well region P141. Another pair of a P-type well region P142 and N-type well region N142 are symmetrically placed with respect to the ground voltage Vss line VS141. A power supply voltage Vdd line VD142 is placed below, in FIG. 4, the N-type well region N142. Pin grids are indicated by the alternate long and short dashed lines, and gate grids are indicated by the dotted lines. The ratio of the pin grid pitch to the gate grid pitch is set at 2:3. In the N-type well region N141, gate electrodes GE141, GE142, GE143, and GE144 are formed, and P-type diffusion layers are formed on the two sides of each of these gate electrodes to form PMOS transistors PM141, PM142, PM143, and PM144, respectively. In the P-type well region P141, the gate electrodes GE141, GE142, GE143, and GE144 are so formed as to extend, and N-type diffusion layers are formed on the two sides of each of these gate electrodes to form NMOS transistors NM141, NM142, NM143, and NM144, respectively. On the boundary line between the N-type well region N141 and P-type well region P141, input/output terminals I/O141 to I/O144 are so formed as to be connected to the gate electrodes GE141 to GE144, respectively. In the P-type well region P142, gate electrodes GE145 to GE148 are formed, and N-type diffusion layers are formed on the two sides of each of these gate electrodes to form NMOS transistors NM145 to NM148, respectively. In the N-type well region N142, the gate electrodes GE145 to GE148 are so formed as to extend, and P-type diffusion layers are formed on the two sides of each of these gate electrodes to form PMOS transistors PM145 to PM148, respectively. On the boundary line between the N-type well region N142 and P-type well region P142, input/output terminals I/O145 to I/O148 are so formed as to be connected to the gate electrodes GE145 to GE148, respectively. N-type impurity diffusion layers NS141 and NS142 for applying a power supply voltage Vdd to the N-type wells N141 and N142 and P-type impurity diffusion layers PS141 and PS142 for applying a ground voltage Vss to the P-type wells P141 and P142 are placed in the same cell region as the MOS transistors. Furthermore, a dummy gate electrode DM141 is placed between a cell made up of the PMOS transistor PM141 and NMOS transistor NM141 which share the gate electrode GE141 and a cell made up of the PMOS transistor PM142 and NMOS transistor NM142 which share the gate electrode GE142. A dummy gate electrode DM142 is placed between a cell made up of the PMOS transistor PM143 and NMOS transistor NM143 which share the gate electrode GE143 and a cell made up the PMOS transistor PM144 and NMOS transistor NM144 which share the gate electrode GE144. Also, a dummy gate electrode DM143 is placed between the cell made up of the PMOS transistor PM144 and NMOS transistor NM144 and the N- and P-type impurity diffusion layers NS141 and PS141. Likewise, a dummy gate electrode DM144 is placed between a cell made up of the PMOS transistor PM145 and NMOS transistor NM145 and a cell made up the PMOS transistor PM146 and NMOS transistor NM146. A dummy gate electrode DM145 is placed between the cell made up of the PMOS transistor PM146 and NMOS transistor NM146 and a cell made up the PMOS transistor PM147 and NMOS transistor NM147. A dummy gate electrode DM146 is placed between a cell made up of the PMOS transistor PM148 and NMOS transistor NM148 and the N- and P-type impurity diffusion layers NS142 and PS142. In addition to the first to third characteristic features of the third embodiment described above, the fourth embodiment has the fourth characteristic feature that the dummy gates formed between the adjacent cells make the MOS transistor gate placement more uniform, and improve the accuracy of processing. (5) Fifth Embodiment The fifth embodiment of the present invention will be described below. In the first to fourth embodiments described above, the power supply voltage Vdd is applied to the N-type well, and the ground voltage Vss is applied to the P-type well. This embodiment differs from the above embodiments in that a substrate potential different from the power supply voltage Vdd is applied to an N-type well, and a substrate potential different from the ground voltage Vss is applied to a P-type well. An example of this arrangement is the fifth embodiment of the present invention, and the arrangement is shown in FIG. 5. An N-type well region N151 and P-type well region P151 are placed in a surface portion of a semiconductor substrate. A power supply voltage Vdd line VD151 and ground voltage Vss line VS151 are placed along one direction (the horizontal direction in FIG. 5) above and below, respectively, in FIG. 5, the pair of the N-type well region N151 and P-type well region P151. In addition, substrate potential supply cells for applying a substrate voltage Vbp different from a power supply voltage Vdd to the N-type well N151 and a substrate voltage Vbn different from a ground voltage Vss to the P-type well P151 are formed in the same cell region as MOS transistors. That is, an N-type impurity diffusion layer NS151 is formed in the N-type well N151, and a P-type impurity diffusion layer PS151 is formed in the P-type well P151. Furthermore, in a direction (vertical direction in FIG. 5) perpendicular to the power supply voltage Vdd line VD151 and ground voltage Vss line VS151, a substrate voltage Vbp line Vbp151 and substrate voltage Vbn line Vbn151 are placed in an interconnection layer above the power supply voltage Vdd line VD151 and ground voltage Vss line VS151 in accordance with pin grids. The N-type impurity diffusion layer NS151 is electrically connected to the substrate voltage Vbp line Vbp151, and the P-type impurity diffusion layer PS151 is electrically connected to the substrate voltage Vbn line Vbn151. As in the first to fourth embodiments described above, pin grids as a reference of a metal pin pitch are indicated by the alternate long and short dashed lines in the vertical direction of FIG. 5, and gate grids as a reference of the pitch of the gate electrodes of MOS transistors are indicated by the dotted lines. In this embodiment, as in the above embodiments, the ratio of the pin grid pitch to the gate grid pitch is set at 2:3. In the N-type well region N151, a gate electrode GE151 is formed on the substrate, and P-type diffusion layers are formed on the two sides of this gate electrode to form a PMOS transistor PM151. Similarly, gate electrodes GE152, GE153, and GE154 are formed, and P-type diffusion layers are formed on the two sides of each of these gate electrodes to form PMOS transistors PM152, PM133, and PM154, respectively. In the P-type well region P151, the gate electrodes GE151, GE152, GE153, and GE154 are so formed as to extend, and N-type diffusion layers are formed on the two sides of each of these gate electrodes to form NMOS transistors NM151, NM152, NM153, and NM154, respectively. As in the second embodiment, a cell made up of the PMOS transistor PM154 and NMOS transistor NM154 is formed adjacent to cells made up of the PMOS transistor PM151 and NMOS transistor NM151, the PMOS transistor PM152 and NMOS transistor NM152, and the PMOS transistor PM153 and NMOS transistor NM153. On the boundary line between the N-type well region N151 and P-type well region P151, input/output terminals I/O151 to I/O154 are so formed as to be connected to the gate electrodes GE151 to GE154, respectively. The MOS transistors PM151 to PM154 and NM151 to NM154 forming the circuit are normalized when they are placed such that the gate electrodes GE151 to GE154 are placed on the gate grids. Also, the input/output terminals I/O151 to I/O154 formed between the plurality of MOS transistors are placed by taking account of differences between the gate grids and pin grids. Furthermore, unlike in the first to fourth embodiments, to apply the substrate voltage Vbp different from the power supply voltage Vdd and the substrate voltage Vbn different from the ground voltage Vss, the substrate voltage Vbp line Vbp151 and substrate voltage Vbn line Vbn151 are connected to the diffusion layers NS151 and PS151 for applying the substrate bias voltage to the N-type well N151 and P-type well P151, respectively. A metal interconnection MP151 in the first layer is connected to the diffusion layer NS151 by a contact CT151, and the metal interconnection MP151 is connected to the substrate voltage Vbp line Vbp151 in the second layer by a via hole VIA151. Likewise, a metal interconnection MP152 in the first layer is connected to the diffusion layer PS151 by a contact CT152, and the metal interconnection MP152 is connected to the substrate voltage Vbn line Vbn151 in the second layer by a via hole VIA152. Similar to the above embodiments, this embodiment having the above arrangement can increase the cell placement efficiency and contribute to micropatterning. (6) Sixth Embodiment The sixth embodiment of the present invention will be described below with reference to FIG. 6. In each of the first to fourth embodiments described previously, a plurality of MOS transistors forming the circuit are normalized when they are placed such that their gate electrodes are placed on the gate grids. In addition, in each of the above embodiments, metal interconnections are formed on the pin grids by normalization. FIG. 6 shows a practical placement of the metal interconnections. As in the fifth embodiment, a power supply voltage Vdd line VD161 and ground voltage Vss line VS161 are placed along one direction as a first interconnection layer. In a direction perpendicular to this direction, a substrate voltage Vbp line Vbp161 and substrate voltage Vbn line Vbn161 are placed as a second interconnection layer in accordance with pin grids 1. The same reference numerals as in the fifth embodiment denote the same elements, and a detailed explanation thereof will be omitted. In this embodiment, pin grids 2 are additionally formed in a direction perpendicular to the pin grids 1. The pin grids 1 and pin grids 2 can have the same interconnection pitch or different interconnection pitches. In accordance with the pin grids 2, metal interconnections ML161 and ML162 are placed as a third interconnection layer. In this embodiment, the pin grids 1 and gate grids are set in the same direction, the gates of MOS transistors are placed in accordance with the gate grids, input/output terminals are placed by taking account of the gate grids and pin grids, and the second interconnection layer is placed in accordance with the pin grids 1. In addition, the pin grids 2 are set in the direction perpendicular to the pin grids 1 and gate grids, and the third interconnection layer is placed in accordance with the pin grids 2. Since this placement increases the cell placement efficiency, the element area can be reduced. Each of the above embodiments is merely an example and hence does not limit the present invention, so each embodiment can be variously modified without departing from the technical scope of the present invention. For example, in each of the above embodiments, the ratio of the pin grid pitch to the gate grid pitch is set at 2:3. However, this ratio can be set at any arbitrary value. In the semiconductor integrated circuits and the methods of designing the same according to the above embodiments, the gate grids and pin grids are set in the cell region, the gate electrodes of MOS transistors are placed in accordance with the gate grids, and metal interconnections are placed in accordance with the pin grids. This increases the cell placement efficiency. | <SOH> BACKGROUND OF THE INVENTION <EOH>The present invention relates to a semiconductor integrated circuit and a method of designing the same and, more particularly, to a semiconductor integrated circuit suited to laying out standard cells. Recently, the circuit scale of semiconductor integrated circuits is abruptly increasing, and demands for shortening the development time are also increasing. Accordingly, a method has been extensively used which does not cause a circuit designer to plan and design a circuit configuration for realizing logic by himself or herself, but designs a circuit block for implementing a desired function by performing logic synthesis, placement, and routing by using software for performing logic synthesis. In designing circuit blocks forming a semiconductor device as described above, a standard cell is used to perform logic synthesis and implement the circuit blocks by using software on the basis of functionally described design data. A standard cell is a small-scale circuit (to be referred to as a cell hereinafter) preformed to realize basic logic, and prepared for each of a plurality of types of logic. In addition, even for single logic, a plurality of cells having different load driving forces, i.e., different sizes are prepared to control various loads. A set of a plurality of types of cells is called a standard cell library. FIG. 7 is a plan view showing a conventional standard cell layout. In a surface portion of a semiconductor substrate, an N-type well region N 1 and P-type well region P 1 are placed. In the N-type well region N 1 , a gate electrode GE 1 is formed on the substrate. On the two sides of the gate electrode GE 1 , a P-type impurity is ion-implanted to form P-type diffusion layers, thereby forming a PMOS transistor PM 1 . In the P-type diffusion layers, a source electrode SE 1 is formed on a source region, and a drain electrode DE 1 is formed on a drain region. Likewise, in the P-type well region P 1 , the gate electrode GE 1 is so formed as to extend, and an N-type impurity is ion-implanted on the two sides of the gate electrode GE 1 to form N-type diffusion layers, thereby forming an NMOS transistor NM 1 . In the N-type diffusion layers, a source electrode SE 2 is formed on a source region, and a drain electrode DE 1 is formed on a drain region. An N-type diffusion layer NS 1 for fixing the substrate bias potential is placed in the end portion of the N-type well region N 1 , and a metal interconnection MW 1 is placed around the N-type diffusion layer NS 1 . A P-type diffusion layer PS 1 for fixing the substrate bias potential is placed in the end portion of the P-type well region P 1 , and a metal interconnection MW 2 is placed around the P-type diffusion layer PS 1 . The source electrode SE 1 is connected to the metal interconnection MW 1 , and the source electrode SE 2 is connected to the metal interconnection MW 2 . In the conventional device as described above, the diffusion layers and metal interconnections for applying the substrate bias potential to the P- and N-type wells formed in the surface of the semiconductor substrate are placed in a standard cell. As these diffusion layers for fixing the substrate bias, impurities are ion-implanted by using masks to form the N-type diffusion layer NS 1 in the N-type well and the P-type diffusion layer PS 1 in the P-type well. As micropatterning progresses, however, it is found that the design rule for impurity ion implantation makes micropatterning difficult to perform, compared to the design rule for MOS transistor formation and metal interconnection. This makes it difficult to decrease a width d11 of the power lines MW 1 and MW 2 so formed as to surround the N- and P-type diffusion layers NS 1 and PS 1 , respectively, shown in FIG. 7 , thereby failing further micropatterning. In addition, pin grids which define the pitch of metal interconnections is conventionally used as a reference for laying out cells and metal interconnections. FIG. 8 shows the pitch of metal pins MP as a pin grid pitch MGP. Unfortunately, pin grids are not suited to the cell layout, so intervals between a gate electrode GE 11 of a P-channel MOS transistor PM 11 and N-channel MOS transistor NM 11 , a gate electrode GE 12 of a P-channel MOS transistor PM 12 and N-channel MOS transistor NM 12 , and a gate electrode GE 13 of a P-channel MOS transistor PM 13 and N-channel MOS transistor NM 13 do not match the pin grids. In fact, the layout is random. Consequently, as shown in FIG. 9 , intervals between the gate electrodes of MOS transistors placed in the upper and lower portions are different from each other. More specifically, intervals between a gate electrode GE 21 of a P-channel MOS transistor PM 21 and N-channel MOS transistor NM 21 , a gate electrode GE 22 of a P-channel MOS transistor PM 22 and N-channel MOS transistor NM 22 , and a gate electrode GE 23 of a P-channel MOS transistor PM 23 and N-channel MOS transistor NM 23 placed in the upper portion are different from intervals between a gate electrode GE 24 of an N-channel MOS transistor NM 24 and P-channel MOS transistor PM 24 , a gate electrode GE 25 of an N-channel MOS transistor NM 25 and P-channel MOS transistor PM 25 , a gate electrode GE 26 of an N-channel MOS transistor NM 26 and P-channel MOS transistor PM 26 , and a gate electrode GE 27 of an N-channel MOS transistor NM 27 and P-channel MOS transistor PM 27 placed in the lower portion. This layout difference between the gate electrodes of the upper and lower transistors poses the following problems. Presently, in patterning the gate electrodes of MOS transistors by using a photomask, the phase of exposure light is shifted to increase the degree of micropatterning. Under the circumstances, if the gate electrodes of the upper and lower transistors are placed at irregular intervals as shown in FIG. 9 , the degree of micropatterning is largely limited by the design rule. FIG. 10 shows a diffusion layer D 1 and gate electrodes G 1 and G 2 of transistors placed in the upper portion, and a diffusion layer D 2 and gate electrode G 3 of a transistor placed in the lower portion. Mask patterns MP 1 , MP 2 , and MP 3 are placed in the upper portion as photomasks for patterning the upper gate electrodes G 1 and G 2 . Mask patterns MP 4 and MP 5 are placed as photomasks for patterning the lower gate electrode G 3 . The positions of the upper gate electrodes G 1 and G 2 and the lower gate electrode G 3 are different from each other. Assuming that the first phase of exposure light comes in contact with the end face of the upper mask pattern MP 1 , the second phase comes in contact with the mask pattern MP 2 adjacent to the mask pattern MP 1 , and the first phase comes in contact with the mask pattern MP 3 adjacent to the mask pattern MP 2 . To pattern gate electrodes, therefore, different phases of light must come in contact with adjacent mask patterns. Unfortunately, the lower mask patterns MP 4 and MP 5 are positioned between the upper mask patterns MP 1 and MP 3 , so the second phase of light comes in contact with both of these lower mask patterns. This makes patterning impossible. A difference between the upper and lower mask patterns produces this phase contradiction. To prevent this phase contradiction, it is necessary to increase the spacings between the upper mask patterns MP 1 , MP 2 , and MP 3 and between the lower mask patterns MP 4 and MP 5 , and this increases the cell size. References disclosing semiconductor integrated circuits using the conventional standard cell are as follows. Japanese Patent Laid-Open No. 10-154756 Japanese Patent Laid-Open No. 2001-168291 Japanese Patent Laid-Open No. 2000-22084 As described above, a region for supplying the substrate potential conventionally interferes with micropatterning. In addition, although the cell placement is based on pin grids, the placement of the gate electrodes of MOS transistors is irregular. As a consequence, the cell area increases by large limitations on the design rules. | <SOH> SUMMARY OF THE INVENTION <EOH>According to one aspect of the present invention, there is provided a semiconductor integrated circuit comprising: a cell region in which a plurality of MOS transistors forming at least one cell are placed; and first and second power lines placed along one direction in a peripheral portion of said cell region, wherein in said cell region, gate grids configured to define a first pitch in said one direction and pin grids for defining a second pitch in said one direction are set, gate electrodes of said MOS transistors are placed in accordance with the gate grids, and an interconnection layer is placed in accordance with the pin grids. According to one aspect of the present invention, there is provided a method of designing a semiconductor integrated circuit, comprising: providing a cell region in which a plurality of MOS transistors forming at least one cell are placed, setting gate grids for defining a first pitch in one direction and pin grids for defining a second pitch in the one direction; placing first and second power lines along the one direction in a peripheral portion of the cell region; placing the MOS transistors such that gate electrodes are positioned on the gate grids; and placing an interconnection layer in accordance with the pin grids. | 20040406 | 20070417 | 20050106 | 63176.0 | 0 | POTTER, ROY KARL | SEMICONDUCTOR INTEGRATED CIRCUIT AND METHOD OF DESIGNING THE SAME | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,817,836 | ACCEPTED | Optical head and optical recording and reproducing apparatus | An optical head is provided with: an objective-lens-use opening that determines an aperture of the objective lens; a light-source light-quantity controlling opening that aperture-controls light that has been separated by the light separation device; a light detector that receives light that has been aperture-controlled by the light-source light-quantity controlling opening; and a light detector that receives light that has been reflected by the optical recording medium, and has an arrangement in which: the length of the optical light path from the spherical aberration correcting device to the objective-lens-use opening is made virtually the same as a length of the optical light path from the spherical aberration correcting device to the light-source light-quantity controlling opening, and the aperture of the light-source light-quantity controlling opening has virtually the same size as the aperture of the objective-lens-use opening. The objective of the present invention is to provide an optical head in which a signal outputted from the light quantity detection device is unchanged even when the spherical aberration correcting device is driven so that by using this signal, the quantity of light from the light source is set to an appropriate value. | 1. An optical head performs recording and/or reproducing of a signal to an optical recording medium, comprising: a light source; an objective lens that converges light released from the light source onto the optical recording medium; an objective-lens-use opening that determines an aperture of the objective lens; a spherical aberration correcting device that corrects spherical aberration that occurs when the optical recording medium has a base-substrate thickness that deviates from a standard base-substrate thickness; a light separation device that is placed in a light path from the spherical aberration correcting device to the optical recording medium; a light-source light-quantity controlling opening that aperture-controls light that has been separated by the light separation device; a first light detector that receives light that has been aperture-controlled by the light-source light-quantity controlling opening; and a second light detector that receives light that has been reflected by the optical recording medium, wherein: a length of an optical light path from the spherical aberration correcting device to the objective-lens-use opening is made substantially the same as a length of an optical light path from the spherical aberration correcting device to the light-source light-quantity controlling opening, and the aperture of the light-source light-quantity controlling opening substantially has the same size as the aperture of the objective-lens-use opening. 2. The optical head according to claim 1, wherein the spherical aberration correcting device corrects the spherical aberration by generating at least one of a converging light and a diverging light. 3. The optical head according to claim 2, wherein the spherical aberration correcting device is constituted by a group of positive lenses and a group of negative lenses. 4. The optical head according to claim 1, wherein the spherical aberration correcting device is an optical element comprising a phase change layer placed between a pair of substrates having transparent conductive thin films. 5. The optical head according to claim 4, wherein light that is made incident on the phase change layer is converted to diverging light or converging light by the phase change layer. 6. The optical head according to claim 1, wherein the optical head further comprises a base-substrate thickness detection device that detects a base substrate thickness of the optical recording medium. 7. The optical head according to claim 6, wherein the base-substrate thickness detection device comprises: a light source; a lens that converges light released from the light source on the optical recording medium; and a light detector that detects light that has been reflected by the optical recording medium. 8. The optical head according to claim 6, wherein the base-substrate thickness detection device detects information relating to the base-substrate thickness based upon two focal points of a first light ray on the side closer to a light axis of light and a second light ray on the outside of the first light ray. 9. The optical head according to claim 1, wherein the objective lens has an NA of not less than 0.6. 10. The optical head according to claim 1, wherein the light source has a wavelength of not more than 450 nm. 11. An optical head performs recording and/or reproducing of a signal to an optical recording medium, comprising: a light source; an objective lens that converges light released from the light source onto the optical recording medium; a spherical aberration correcting device that corrects spherical aberration that occurs when the optical recording medium has a base-substrate thickness that deviates from a standard base-substrate thickness; a light separation device that is placed in a light path from the spherical aberration correcting device to the optical recording medium; a lens that converges light that has been separated by the light separation device; a light-source light-quantity controlling opening that aperture-controls light that has been converged by the lens; a first light detector that receives light that has been aperture-controlled by the light-source light-quantity controlling opening; and a second light detector that receives light that has been reflected by the optical recording medium. 12. The optical head according to claim 11, wherein the spherical aberration correcting device corrects the spherical aberration by generating at least one of a converging light and a diverging light. 13. The optical head according to claim 12, wherein the spherical aberration correcting device is constituted by a group of positive lenses and a group of negative lenses. 14. The optical head according to claim 11, wherein the spherical aberration correcting device is an optical element comprising a phase change layer placed between a pair of substrates having transparent conductive thin films. 15. The optical head according to claim 14, wherein light that is made incident on the phase change layer is converted to diverging light or converging light by the phase change layer. 16. The optical head according to claim 11, wherein the optical head further comprises a base-substrate thickness detection device that detects a base substrate thickness of the optical recording medium. 17. The optical head according to claim 16, wherein the base-substrate thickness detection device comprises: a light source; a lens that converges light released from the light source on the optical recording medium; and a light detector that detects light that has been reflected by the optical recording medium. 18. The optical head according to claim 16, wherein the base-substrate thickness detection device detects information relating to the base-substrate thickness based upon two focal points of a first light ray on the side closer to a light axis of light and a second light ray on the outside of the first light ray. 19. The optical head according to claim 11, wherein the objective lens has an NA of not less than 0.6. 20. The optical head according to claim 11, wherein the light source has a wavelength of not more than 450 nm. 21. An optical head performs recording and/or reproducing of a signal to an optical recording medium, comprising: a light source; an objective lens that converges light released from the light source onto the optical recording medium; a spherical aberration correcting device that corrects spherical aberration that occurs when the optical recording medium has a base-substrate thickness that deviates from a standard base-substrate thickness; a light separation device that is placed in a light path from the light source to the spherical aberration correcting device; a first light detector that receives light that has been separated by the light separation device; and a second light detector that receives light that has been reflected by the optical recording medium. 22. The optical head according to claim 21, wherein the spherical aberration correcting device corrects the spherical aberration by generating at least one of a converging light and a diverging light. 23. The optical head according to claim 22, wherein the spherical aberration correcting device is constituted by a group of positive lenses and a group of negative lenses. 24. The optical head according to claim 21, wherein the spherical aberration correcting device is an optical element comprising a phase change layer placed between a pair of substrates having transparent conductive thin films. 25. The optical head according to claim 24, wherein light that is made incident on the phase change layer is converted to diverging light or converging light by the phase change layer. 26. The optical head according to claim 21, wherein the optical head further comprises a base-substrate thickness detection device that detects a base substrate thickness of the optical recording medium. 27. The optical head according to claim 26, wherein the base-substrate thickness detection device comprises: a light source; a lens that converges light released from the light source on the optical recording medium; and a light detector that detects light that has been reflected by the optical recording medium. 28. The optical head according to claim 26, wherein the base-substrate thickness detection device detects information relating to the base-substrate thickness based upon two focal points of a first light ray on the side closer to a light axis of light and a second light ray on the outside of the first light ray. 29. The optical head according to claim 21, wherein the objective lens has an NA of not less than 0.6. 30. The optical head according to claim 21, wherein the light source has a wavelength of not more than 450 nm. 31. An optical recording and reproducing apparatus performing recording and/or reproducing of a signal to an optical recording medium, comprising the optical head according to claim 1. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head used in optical information processing, optical communication or the like and an optical recording and reproducing apparatus using the optical head. 2. Description of the Related Art Recently, a digital versatile disc (DVD) has attracted attention as a high-capacity optical recording medium because it can record digital information in a recording density which is about 6 times as high as a compact disc (CD). However, a further high-density optical recording medium is demanded as capacity of information becomes large. Here, in order to realize a density higher than the DVD (wavelength is 660 nm and numerical aperture (NA) is 0.6), it is necessary to use a light source emitting a light having shorter wavelength and to further increase the NA of the objective lens. For example, when blue laser having a wavelength of 405 nm and an objective lens having NA of 0.85 are used, a recording density which is 5 times as high as the DVD can be attained. However, since the high-density optical recording medium apparatus using the blue laser has very strict reproducing and/or recording margin, in other words, a permissible level for a fluctuation of characteristic in reproducing or recording is limited very strictly, aberration generated by a fluctuation in the base-substrate thickness of an optical recording medium becomes a problem. It is to be noted that the wording “reproducing and/or recording” means “at least one of reproducing and recording”, in the specification, to simplify the description. In relating to this problem, Japanese Patent Laid-open Publication No. 2000-131603 discloses an optical head which aims to carry out reproducing and recording operations while correcting aberration due to a fluctuation in the base-substrate thickness of an optical recording medium. One example of the above conventional optical head is described with reference to the drawing. FIG. 9 is a schematic view showing a constitution of the conventional optical head. In FIG. 9, reference numeral 91 designates a light source, reference numeral 92 designates a diffraction grating, reference numeral 93 designates is a collimator lens, reference numeral 94 designates a polarized beam splitter, reference numeral 95 designates a ¼ wavelength plate, reference numeral 96 designates a group of aberration correcting lenses, reference numeral 97 designates an objective lens, reference numeral 98 designates an optical recording medium, reference numeral 99 designates a focusing lens, reference numeral 100 designates a multi-lens and reference numeral 101 designates a light detector. The light source 91, which is a semiconductor laser, serves as a light source that outputs coherent light for use in recording and reproducing to a recording layer of the optical recording medium 98. The diffraction grating 92 has a structure in which a concave/convex pattern is formed on a surface of a glass substrate, and serves an optical element which divides an incident beam into three beams so as to allow detection of a tracking error signal through a so-called three beam method. The collimator lens 93 is a lens which converts diverged light emitted from the light source 91 to parallel light rays. The polarized beam splitter 94 is an optical element which has different transmittance and reflection factor depending on incident polarized light, and is used for separating light. The ¼ wavelength plate 95 is made from a birefringence material, and serves as an optical element that converts linearly polarized light to circularly polarized light. The group of aberration correcting lenses 96, which is used for correcting spherical aberration that occurs when the base-substrate thickness of the optical recording medium 98 is different from a predetermined standard value, is constituted by a group of concave lenses 96a and a group of convex lenses 96b as well as a uniaxial actuator, not shown. And, by changing the distance between the group of concave lenses 96a and the group of convex lenses 96b , it becomes possible to correct the spherical aberration. The above-mentioned standard value is, more preferably, determined based on an optimum design base-substrate thickness as a thickness of the base-substrate of the optical recording medium 98. The group of aberration correcting lenses 96 will be described later in detail The objective lens 97 is a lens for converging light on a recording layer of the optical recording medium 98. The focusing lens 99 is a lens used for converging light reflected from the recording layer of the optical medium 98 onto the light detector 101. The multi-lens 100 has a cylindrical surface as its light incident face, and its light-releasing face forms a rotation symmetrical face with respect to the lens light axis so that astigmatism, which allows the detection of a focus error signal with respect to incident light through a so-called astigmatism method, is given. The light detector 101 receives light reflected by the recording layer of the optical recording medium 98 to convert the light to an electric signal. The following description will discuss operations of the optical head having the above-mentioned arrangement. Linearly polarized light, emitted from the light source 91, is divided into three beams by the diffraction grating 92, and the three divided light beams are converted to parallel light rays by the collimator lens 93. The resulting parallel light rays are allowed to pass through the polarized beam splitter 94, and made incident on the ¼ wavelength plate 95 so that the linearly polarized light is converted into circularly polarized light. The circularly polarized light that has passed through the ¼ wavelength plate 95 is made incident on the group of aberration correcting lenses 96. In this case, in order to correct spherical aberration that occurs when the base-substrate thickness of the optical recording medium 98 deviates from an standard thickness, the incident parallel light rays are converted to diverging light and converging light by changing the distance between the group of concave lenses 96a and the group of convex lenses 96b that constitute the group of aberration correcting lenses 96. Then, the converted light is made incident on the objective lens 97 so that spherical aberration is generated in proportion to a degree of divergence or a degree of convergence of the incident light, and is converged on the optical recording medium 98. Here, since light having wave aberration capable of correcting the wave aberration occurring upon deviation in the base-substrate thickness of the optical recording medium 98 from the standard base-substrate thickness is converged thereon by the objective lens 97, a light spot that is free from aberration, that is, a light spot that is limited to the diffraction limit, is formed on the optical recording medium 98. Next, the circularly polarized light, reflected from the optical recording medium 98, is allowed to pass through the group of aberration correcting lenses 96, and is input to the ¼ wavelength plate 95, then is converted to linearly polarized light in a direction orthogonal to the linearly polarized light that has been emitted from the light source 91. The linearly polarized light, converted by the ¼ wavelength plate 95, is reflected by the polarized beam splitter 94, and converged by the focusing lens 99 without returning to the light source 91 so that astigmatism is given to the light made incident by the multi-lens 100 and the resulting light is converged on the light detector 101. The light detector 101 outputs a focus error signal that indicates a focused state of light on the optical recording medium 98, and also outputs a tracking error signal that indicates an irradiation position of light. Here, the focus error signal and the tracking error signal are detected by known techniques such as an astigmatism method and a three beam method. Based upon the focus error signal, a focus control device, not shown, controls the position of the objective lens 97 in the light axis direction so that the light is always converged on the optical recording medium 98 in the focused state. Moreover, based upon the tracking error signal, a tracking control device, not shown, controls the position of the objective lens 97 so that light is converged on a desired track on the optical recording medium 98. Furthermore, information recorded on the optical recording medium 98 is also obtained by the light detector 101. Here, the following description will discuss the spherical aberration correcting operation that is available by the use of the group of aberration correcting lenses 96, in detail. When the distance between the group of concave lenses 96a and the group of convex lenses 96b constituting the group of aberration correcting lenses 96 is narrowed, the parallel light rays are converted to diverging light, and when the distance is widened, the parallel light rays are converted to converging light. In other words, by changing the distance between the group of concave lenses 96a and the group of convex lenses 96b , it is possible to generate light rays having power components with different codes. Here, in the case when light having a power component is made incident on the objective lens 97, spherical aberration occurs in the light converged by the objective lens 97, and since the code is dependent on the code of the incident power component, it is possible to correct the spherical aberration that occurs upon deviation of the base-substrate thickness of the optical recording medium 98 from a standard base-substrate thickness by using this spherical aberration. With this arrangement, since the spherical aberration caused by the deviation in the base-substrate thickness of the optical recording medium 98 can be corrected by using the group of aberration correcting lenses 96, it is possible to carry out stable reproducing and recording operations. In the optical head having the above-mentioned conventional arrangement, however, no description has been given to a light-quantity detection device that is required to control the quantity of light released from the light source 91, with the result that a problem arises due to the position of this light-quantity detection device. Referring to FIG. 10, the following description discusses this problem in detail. Here, only the points in which an optical head shown in FIG. 10 is different from the optical head of FIG. 9 are that a mirror and a light-quantity detection device are further installed and that the ¼ wavelength plate is placed between the mirror and the objective lens; except for these points, it has the same arrangement as the optical head of FIG. 9. Therefore, in FIG. 10, the same parts as those of the optical head of FIG. 9 are used, unless otherwise indicated, and those components indicated by the same reference numerals have the same functions, unless otherwise indicated. In FIG. 10, reference numeral 201 is a mirror, reference numeral 202 is a condenser lens and reference numeral 203 is a light-source light-quantity controlling light detector. Here, the light-quantity detection device is constituted by the condenser lens 202 and the light-quantity controlling light detector 203. The mirror 201 is an optical element that reflects incident light to direct the resulting light to the optical recording medium 98, and with respect to certain linearly polarized light, transmits 5% thereof, while reflecting 95% thereof, and with respect to linearly polarized light orthogonal to the above-mentioned linearly polarized light, reflects 100% thereof. The following description will discuss operations of the optical head having the above-mentioned arrangement. Linearly polarized light, released from the light source 91, is divided into three beams by the diffraction grating 92, and the three divided light beams are converted to parallel light rays by the collimator lens 93. The light, converted into the parallel light rays, are allowed to pass through the polarized beam splitter 94, and made incident on the group of aberration correcting lenses 96. In this case, in order to correct spherical aberration that occurs when the base-substrate thickness deviates from a standard value, the incident parallel light rays are converted to diverging light and converging light by changing the distance between the group of concave lenses 96a and the group of convex lenses 96b that constitute the group of aberration correcting lenses 96; thus, the converted light is made incident on the mirror 201 so that one portion (5%) thereof is allowed to transmit, while most (95%) of it is reflected, and changed in its advancing direction to the optical recording medium 98. This reflected light is made incident on the ¼ wavelength plate 95 to be converted from linearly polarized light to circularly polarized light; thus, this circularly polarized light is made incident on the objective lens 97 so that spherical aberration is generated in proportion to a degree of divergence or a degree of convergence of the incident light, and is further converged on the optical recording medium 98. Here, since light having wave aberration capable of correcting the wave aberration occurring upon deviation in the bas-substrate thickness of the optical recording medium 98 from the standard thickness is converged thereon by the objective lens 97, a light spot that is free from aberration, that is, a light spot that is limited to the diffraction limit, is formed on the optical recording medium 98. Next, the circularly polarized light, reflected from the optical recording medium 98, is inputted to the ¼ wavelength plate 95, and converted to linearly polarized light in a direction orthogonal to the linearly polarized light released from the light source 91. The linearly polarized light converted by the ¼ wavelength plate 95 is all reflected by the mirror 201, allowed to pass through the group of aberration correcting lenses 96, and reflected by the polarized beam splitter 94 and further converged by the focusing lens 99 without returning to the light source 91 so that astigmatism is given to the light made incident by the multi-lens 100 and the resulting light is converged on the light detector 101. The light detector 101 outputs a focus error signal that indicates a focused state of light on the optical recording medium 98, and also outputs a tracking error signal that indicates an irradiation position of light. Here, the focus error signal and the tracking error signal are detected by known techniques such as an astigmatism method and a three beam method. Based upon the focus error signal, a focus control device, not shown, controls the position of the objective lens 97 in the light axis direction so that the light is always converged on the optical recording medium 98 in the focused state. Moreover, based upon the tracking error signal, a tracking control device, not shown, controls the position of the objective lens 97 so that light is converged on a desired track on the optical recording medium 98. Furthermore, information recorded on the optical recording medium 98 is also obtained by the light detector 101. Moreover, the light that has passed through the mirror 201 is converged on the light-source light-quantity controlling light detector 203 by the condenser lens 202, and the light-source light-quantity controlling light detector 203 outputs an electric signal corresponding to the quantity of light released from the light source 1. The necessity of the above-mentioned light-quantity detection device is explained as follows: Since the light source 91 is formed by a semiconductor laser, the light source 91 has a temperature rise when it continues to output light, with the result that the quantity of light to be outputted from the light source 91 tends to vary even when the current used for controlling the light source 91 is constant. Therefore, by detecting one portion of the light released from the light source 91, it becomes possible to control the quantity of light released from the light source 91. However, in the case when the signal detected by the light-quantity detection device is varied independent of the quantity of light from the light source 91, a serious problem is raised. For example, even in the case of constant quantity of light from the light source 91, when the signal outputted from the light quantity detection device becomes smaller, the light source 91 is controlled so as to release a greater quantity of light, with the result that a great quantity of light is released during a reproducing operation of the optical recording medium 98 to cause erroneous erasing of information recorded in the optical recording medium 98. In contrast, even in the case of constant quantity of light from the light source 91, when the signal outputted from the light quantity detection device becomes greater, the light source 91 is controlled so as to release a smaller quantity of light, with the result that the quantity of light fails to reach a sufficient quantity required for recording during a recording operation on the optical recording medium 98 to cause an insufficient recording process. In other words, a serious problem is raised unless the signal detected by the light-quantity detection device varies in response to the quantity of light released from the light source 91. FIG. 11 schematically shows light to be made incident on the objective lens 97 when the group of aberration correcting lenses 96 is driven to correct spherical aberration. In FIG. 11, in the case when the base-substrate thickness of the optical recording medium 98 is thicker than a standard thickness, the distance between the group of concave lenses 96a and the group of convex lenses 96b becomes wider so that the light is made incident on the objective lens 97 as converged light. This state is indicated by a solid line. In the case when the base-substrate thickness of the optical recording medium 98 is thinner than the standard base-substrate thickness, the distance between the group of concave lenses 96a and the group of convex lenses 96b becomes smaller so that the light is made incident on the objective lens 97 as diverged light. This state is indicated by an imaginary line. Here, it is supposed that the light to be used in the light-quantity detection device is located at position A in FIG. 11. In FIG. 10, an aperture (not shown), which is used for controlling the quantity of transmitted light, is formed between the mirror 201 and the condenser lens 202, and this is schematically indicated as an aperture 110H (opening) in FIG. 11. This aperture 110H is provided by forming a hole (opening) in a plate member 110. The member 110 having aperture 110H may be a hold member for holding the group of convex lenses 96b. As shown by FIG. 11, although the group of aberration correcting lenses is designed so as to make the quantity of incident light onto the objective lens 97 constant independent of the location of the group of concave lenses 96a while the group of concave lenses 96a is shifted to correct spherical aberration, the light to be made incident on the light-source light-quantity controlling light detector 203 is shield by the member 110 having the aperture 110H on the peripheral portion thereof depending on the position of the group of concave lenses 96a , with the result that the quantity of light to be detected by the light-source light-quantity controlling light detector 203 is varied. In other words, although the quantity of light of the light source 91 is not changed, the quantity of light to be made incident on the light-source light-quantity controlling light detector 203 is varied, as described above, with the result that a signal is outputted as if it were derived from a change in the quantity of light in the light source; consequently, problems are raised in that recorded information is erased during reproducing, and in that insufficient recording is caused due to a failure in outputting a sufficient quantity of light upon recording. SUMMARY OF THE INVENTION The present invention has been devised to solve the above-mentioned conventional problems, and its first objective is to provide an optical head in which a signal, outputted from the light-source light-quantity controlling light detector 203, is only dependent on a quantity of light to be released from the light source even when spherical aberration has been corrected. Moreover, a second objective of the present invention is to provide an optical recording/reproducing apparatus makes it possible to detect a quantity of light to be released from the light source accurately even in the case when there is a deviation from a standard value in the base-substrate thickness of the optical recording medium and spherical aberration caused by the deviation has been corrected, and consequently to carry out stable reproducing and recording operations. In order to achieve the above-mentioned objectives, an optical head of the present invention, which records and/or reproduces a signal on or from an optical recording medium, is provided with: a light source; an objective lens that converges light released from the light source onto the optical recording medium; an objective-lens-use opening that determines an aperture of the objective lens; a spherical aberration correcting device that corrects spherical aberration that occurs when the optical recording medium has a base-substrate thickness that deviates from a standard base-substrate thickness; a light separation device that is placed in a light path from the spherical aberration correcting device to the optical recording medium; a light-source light-quantity controlling opening that aperture-controls light that has been separated by the light separation device; a first light detector that receives light that has been aperture-controlled by the light-source light-quantity controlling opening; and a second light detector that receives light that has been reflected by the optical recording medium, and in this arrangement, a length of the optical light path from the spherical aberration correcting device to the objective-lens-use opening is made substantially the same as a length of the optical light path from the spherical aberration correcting device to the light-source light-quantity controlling opening, and the aperture of the light-source light-quantity controlling opening substantially has the same size as the aperture of the objective-lens-use opening. With this arrangement, even when the spherical aberration correcting device is driven, the signal to be outputted by the first light detector that receives light that has been aperture-controlled by the light-source light-quantity controlling opening is prepared as a signal that corresponds to only the quantity of light released from the light source; thus, since the light source can be controlled by using this signal, it becomes possible to carry out stable reproducing and recording operations. Also, in order to achieve the above-mentioned objectives, another optical head of the present invention, which records and/or reproduces a signal on or from an optical recording medium, is provided with: a light source; an objective lens that converges light released from the light source onto the optical recording medium; a spherical aberration correcting device that corrects spherical aberration that occurs when the optical recording medium has a base-substrate thickness that deviates from a standard base-substrate thickness; a light separation device that is placed in a light path from the spherical aberration correcting device to the optical recording medium; a lens that converges light that has been separated by the light separation device; a light-source light-quantity controlling opening that aperture-controls light that has been converged by the lens; a first light detector that receives light that has been aperture-controlled by the light-source light-quantity controlling opening; and a second light detector that receives light that has been reflected by the optical recording medium. With this arrangement, even when the spherical aberration correcting device is driven, a signal, outputted by the first light detector that receives light that is aperture-controlled by the light-source light-quantity controlling opening, is prepared as a signal that corresponds to only the quantity of light released from the light source; thus, it is possible to control the light source by using this signal, and consequently to carry out stable reproducing and recording operations. Moreover, since the distance from the spherical aberration correcting device to the light detector that receives light that has been aperture-controlled by the light-source light-quantity controlling opening can be shortened, it becomes possible to miniaturize the optical head effectively. In order to achieve the above-mentioned objectives, another optical head of the present invention, which records or reproduces a signal on or from an optical recording medium, is provided with: a light source; an objective lens that converges light released from the light source onto the optical recording medium; a spherical aberration correcting device that corrects spherical aberration that occurs when the optical recording medium has a base-substrate thickness that deviates from a standard base substrate thickness; a light separation device that is placed in a light path from the light source to the spherical aberration correcting devise; a first light detector that receives light that has been separated by the light separation device; and a second light detector that receives light that has been reflected by the optical recording medium. With this arrangement, even when the spherical aberration correcting device is driven, the signal to be outputted by the first light detector that receives light separated by the light separation device is prepared as a signal that corresponds to only the quantity of light released from the light source; thus, it becomes possible to control the light source by using this signal, and consequently to carry out stable reproducing and recording operations. In the above-mentioned optical head, the spherical aberration correcting device is preferable to correct the spherical aberration by the spherical aberration correcting device generates at least one of converging light and diverging light. More specifically, the spherical aberration correcting device is more preferably constituted by a group of positive lenses and a group of negative lenses. With this arrangement, spherical aberration that occurs when the base-substrate thickness of the optical recording medium deviates from the standard base-substrate thickness can be corrected in both of the forward path and return path of the optical head; thus, it becomes possible to obtain a stable control signal and reproducing signal. In the above-mentioned optical head, the spherical aberration correcting device is preferably prepared as an optical element having a phase change layer placed between a pair of substrates having transparent conductive thin films. Since this arrangement allows miniaturization of the spherical aberration correcting device, it becomes possible to miniaturize the optical head effectively. In the above-mentioned optical head, light that is made incident on the phase change layer is converted to diverging light or converging light by the phase change layer. With this arrangement, it is possible to prevent degradation in the spherical aberration correcting function even when the lens is shifted. In the above-mentioned optical head, the optical head is preferably provided with a base-substrate thickness detection device that detects a base substrate thickness of the optical recording medium. Since this arrangement makes it possible to detect a deviation in the base-substrate thickness of the optical recording medium from the standard value at any position on the optical recording medium, it is possible to correct spherical aberration with higher precision, and consequently to obtain a stable control signal and reproduced signal. In the above-mentioned optical head, the base-substrate thickness detection device is preferably provided with: a light source; a lens that converges light released from the light source on the optical recording medium; and a light detector that detects light that has been reflected by the optical recording medium. With this arrangement, since the aberration derived from the base-substrate thickness of the optical recording medium is detected by using another optical system, it is possible to detect the aberration derived from the base-substrate thickness of the optical recording medium simultaneously during a reproducing or recording operation. In the above-mentioned optical head, the base-substrate thickness detection device detects information relating to the base-substrate thickness based upon two focal points of a first light ray on the side closer to a light axis of light and a second light ray on the outside of the first light ray. With this arrangement, it is possible to miniaturize the optical head. In the above-mentioned optical head, the objective lens preferably has an NA of not less than 0.6. With this arrangement, in an attempt to achieve higher density in the case of a small aberration margin with respect to recording and reproducing operations, the optical recording medium is allowed to have an expanded tolerance for the deviation of the base-substrate thickness from the standard value. Therefore, it becomes possible to achieve a higher recording density. In the above-mentioned optical head, the light source preferably has a wavelength of not more than 450 nm. With this arrangement, in an attempt to achieve higher density in the case of a small aberration margin with respect to recording and reproducing operations, the optical recording medium is allowed to have an expanded tolerance for the deviation of the base-substrate thickness from the standard base-substrate thickness. Therefore, it becomes possible to achieve a higher recording density. In order to achieve the above-mentioned objectives, an optical recording/reproducing apparatus, which records and/or reproduces a signal on or from an optical recording medium, is provided with the optical head having the above-mentioned arrangement for recording or reproducing a signal on or from an optical recording medium. This apparatus makes it possible to detect a signal corresponding to the quantity of light released from a light source even when the spherical aberration correcting device is driven, and consequently to control the light source by using this signal; thus, it becomes possible to carry out stable reproducing and recording operations. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic drawing that shows an optical head in accordance with a first embodiment of the present invention; FIG. 2 is a schematic drawing that shows another optical head in accordance with a second embodiment of the present invention; FIG. 3 is a drawing that shows a light path of light upon driving a spherical aberration correcting device; FIG. 4 is a schematic drawing that shows still another optical head in accordance with a third embodiment of the present invention; FIG. 5 is a schematic drawing that shows another example of the spherical aberration correcting device; FIG. 6 is a cross-sectional view that shows one example of the spherical aberration correcting device having a phase change layer; FIG. 7 is a drawing that shows one example of an electrode pattern of the spherical aberration correcting device having the phase change layer; FIG. 8 is a schematic drawing that shows an optical recording/reproducing apparatus in accordance with a fourth embodiment of the present invention; FIG. 9 is a schematic drawing that shows one example of a conventional optical head; FIG. 10 is a schematic drawing that shows another example of a conventional optical head; FIG. 11 is a drawing that shows a light path of light up to an objective lens when a spherical aberration correcting device in a optical head is driven; and FIG. 12 is a graph showing a relationship between NA of the objective lens and amount of aberration; DETAILED DESCRIPTION OF THE INVENTION Referring to Figures, the following description will discuss embodiments of the present invention. EMBODIMENT 1 Embodiment 1 discusses one example of an optical head of the present invention. FIG. 1 is a block diagram that shows an optical head of embodiment 1. In FIG. 1, reference numeral 1 is a light source, reference numeral 2 is a diffraction grating, reference numeral 3 is a collimator lens, reference numeral 4 is a polarized beam splitter, reference numeral 5 is a concave lens, reference numeral 6 is a convex lens, reference numeral 7 is a mirror, reference numeral 8 is a ¼ wavelength plate, reference numeral 9 is an objective lens, reference numeral 10 is an optical recording medium, reference numeral 11 is a condenser lens, reference numeral 12 is a cylindrical lens, reference numeral 13 is a light detector (a second light detector), reference numeral 14 is a lens, reference numeral 15 is a light-source light-quantity controlling light detector (a second light detector), reference numeral 16 is an member having an objective-lens-use opening 16H and reference numeral 17 is a member having a light-source light-quantity controlling opening 17H. In this structure, the concave lens 5, the convex lens 6 and a uniaxial actuator, not shown, constitute a spherical aberration correcting device; the lens 14, the light-source light-quantity controlling light detector 15 and the light-source light-quantity controlling opening 17 constitute a light-quantity detection device; the concave lens 5 corresponds to a group of negative lenses; the convex lens 6 corresponds to a group of positive lenses; and the mirror 7 forms a light separation device. That is, in this case, the group of negative lenses is constituted by a concave lens 5, and the group of positive lenses is constituted by a convex lens 6. The light source 1, which is constituted by, for example, a GaN-based semiconductor laser element (wavelength: 405 nm), serves as a light source that outputs coherent light for use in recording and reproducing on and from a recording layer of the optical recording medium 10. The diffraction grating 2 has a structure in which a concave/convex pattern is formed on the surface of a glass substrate, and serves an optical element which divides an incident beam into three beams so as to allow detection of a tracking error signal through a so-called three beam method. The collimator lens 3 is a lens which converts diverged light released from the light source 1 to parallel light rays. The polarized beam splitter 4 is an optical element which has different transmittance and reflection factor depending on the polarizing direction of incident light, and is used for separating light rays. The spherical aberration correcting device, which is used for correcting spherical aberration that occurs when the base-substrate thickness of the optical recording medium 10 deviates from an standard base-substrate thickness as described in detail in relating to the prior art, is constituted by the concave lens 5, the convex lens 6 and the uniaxial actuator (a lens position changing device), not shown, and makes it possible to correct the above-mentioned spherical aberration by changing the distance between the concave lens 5 and the convex lens 6. The mirror 7 serves as an optical element which reflects incident light to direct the resulting light to the optical recording medium 10, and with respect to certain linearly polarized light, transmits 5% thereof, while reflecting 95% thereof, and with respect to linearly polarized light orthogonal to the above-mentioned linearly polarized light, reflects 100% thereof. The ¼ wavelength plate 8 is formed by a birefringence material, and serves an optical element which converts linearly polarized light to circularly polarized light. The objective lens 9 serves as a lens for converging light onto the recording layer of the optical recording medium 10, and has a numerical aperture (NA) of 0.85. The condenser lens 11 is a lens which converges light that has been reflected by the recording layer of the optical recording medium 10 on the light detector 13 (the second light detector). The cylindrical lens 12 has a cylinder face in its light incident face, and its light-releasing face forms a rotation symmetrical face with respect to the lens light axis so that astigmatism that allows the detection of a focus error signal with respect to the incident light through a so-called astigmatism method is given. The light detector 13 receives light reflected by the recording layer of the optical recording medium 10 to convert the light to an electric signal. The lens 14 converges light that has passed through the mirror 7 on the light-source light-quantity controlling light detector 15 (the first light detector). The objective-lens-use opening 16H is used to limit the size of light that is made incident on the objective lens so as to determine the NA of the objective lens, and a member for holding the objective lens 9 is also used as the member 16 having the opening (the objective-lens-use opening 16H). The light-source light-quantity controlling opening 17H is used to limit the quantity of light to be used for controlling the quantity of light of the light source, and a member for holding the lens 14 also forms the member 17 having the opening (the light-source light-quantity controlling opening 17H). In the present embodiment, the light-source light-quantity controlling opening 17H is placed with the same length of light path as that from the spherical aberration correcting device to the objective-lens-use opening 16H, with the size of the opening being set to the same size as the objective-lens-use opening 16H. The following description will discuss operations of the optical head having the above-mentioned arrangement. Linearly polarized light, released from the light source 1, is divided into three beams by the diffraction grating 2, and the three divided light beams are converted to parallel light rays by the collimator lens 3. The light, converted into the parallel light rays, are allowed to pass through the polarized beam splitter 4, and made incident on the spherical aberration correcting device. In this case, in order to correct spherical aberration that occurs when the base-substrate thickness deviates from a standard base-substrate thickness, the incident parallel light rays are converted to diverging light and converging light by changing the distance between the concave lens 5 and the convex lens 6 that constitute the spherical aberration correcting device; thus, the converted light is made incident on the mirror 7 so that one portion thereof is allowed to transmit, while most of it is reflected, and changed in its advancing direction to the optical recording medium 10. This reflected light is made incident on the ¼ wavelength plate 8 to be converted from linearly polarized light to circularly polarized light; thus, this circularly polarized light is aperture-controlled by the objective-lens-use opening 16H, and made incident on the objective lens 9 so that spherical aberration is generated in proportion to a degree of divergence or a degree of convergence of the incident light, and is further converged on the optical recording medium 10. Here, since light having wave aberration capable of correcting the wave aberration occurring upon deviation in the base-substrate of the optical recording medium 10 from the standard value is converged thereon by the objective lens 9, a light spot that is free from aberration, that is, a light spot that is limited to the diffraction limit, is formed on the optical recording medium 10. Next, the circularly polarized light, reflected from the optical recording medium 10, is inputted to the ¼ wavelength plate 8, and converted to linearly polarized light in a direction orthogonal to the linearly polarized light released from the light source 1. The linearly polarized light converted by the ¼ wavelength plate 8 is all reflected by the mirror 7, allowed to pass through the spherical aberration correcting device, and reflected by the polarized beam splitter 4 and further converged by the condenser lens 11 without returning to the light source 1 so that astigmatism is given to the light by the cylindrical lens 12, and the resulting light is converged on the light detector 13. The light detector 13 outputs a focus error signal that indicates the focused state of light on the optical recording medium 10, and also outputs a tracking error signal that indicates the irradiation position of light. Here, the focus error signal and the tracking error signal are detected by known techniques such as an astigmatism method and a three beam method. Based upon the focus error signal, a focus control device, not shown, controls the position of the objective lens 9 in the light axis direction so that the light is always converged on the optical recording medium 10 in the focused state. Moreover, based upon the tracking error signal, a tracking control device, not shown, controls the position of the objective lens 9 so that light is converged on a desired track on the optical recording medium 10. Furthermore, information recorded on the optical recording medium 10 is also obtained by the light detector 13. Moreover, the light that has passed through the mirror 7 is converged on the light-source light-quantity controlling light detector 15, and the light-source light-quantity controlling light detector 15 outputs an electric signal corresponding to the quantity of light released from the light source 1. Here, the following description will discuss the light-quantity detection device in detail. As described in the background of the invention, even when a current used for driving the light source 1 is set to a constant value, the quantity of light to be released from the light source 1 is varied due to temperatures and the like; therefore, the quantity of light released from the light source 1 needs to be detected, and the light source 1 needs to be controlled based upon the detected signal. However, when the detected signal is varied due to factors other than the quantity of light released from the light source 1, the quantity of light released from the light source 1 is varied even when the quantity of light to be released from the light source is unchanged, causing serious problems. The background of the invention also describes that there is a possibility of the above-mentioned problems in the optical head in which the spherical aberration correcting device that corrects spherical aberration by forming diverging light and converging light is used. These problems are caused because the length of light path from the spherical aberration correcting device to the objective-lens-use opening 16H differs from the length of light path from the spherical aberration correcting device to the light-source light-quantity controlling opening 17H, and because the size of the objective-lens-use opening 16H differs from the size of the opening of the light-source light-amount controlling opening 17H. Therefore, in the present embodiment, the light-source light-quantity controlling opening 17H is placed at a position having the same length of light path from the spherical aberration correcting device to the objective-lens-use opening 16H, and the size of the light-source light-quantity controlling opening 17H is the same as the size of the objective-lens-use opening 16H. With this arrangement, even when the spherical aberration correcting device is driven, the signal to be detected by the light detector is only related to variations in the quantity of light to be released from the light source 1; thus, it becomes possible to detect a signal by which the light source 1 is controlled more appropriately. Moreover, even in the case when, depending on the structure of the spherical aberration correcting device, even with a constant quantity of light released from the light source 1, the quantity of light to be released from the objective lens is varied due to variations in the distance of the lenses constituting the spherical aberration correcting device, the signal to be released from the light-quantity detection device is allowed to have the completely same variations; thus, by controlling the signal to be released from the light-quantity detection device to have a constant signal, it is possible to make the quantity of light released from the objective lens 9 constant, and consequently to provide an efficient structure. As described above, with the arrangement in which: the light separation device is placed between the spherical aberration correcting device and the lens 14, the light-source light-quantity controlling opening 17H for aperture-controlling the light separated by the light separation device is placed at a position having the same length of light path from the spherical aberration correcting device to the objective-lens-use opening 16H, and the size of the opening thereof is made the same as the size of the objective-lens-use opening 16, it becomes possible to set the quantity of light to be released from the objective lens to a desired value, independent of environmental changes such as temperature changes, even in the case when the spherical aberration correcting device is driven; therefore, it is possible to prevent recorded information on the optical recording medium from being erroneously erased upon reproduction, and it is also possible to prevent a signal to be released from the objective lens from becoming too small to make the subsequent reproduced signal and control signal too small; thus, it becomes possible to prevent the subsequent failure in the reproducing operation and unstable controlling operations. It is also possible to prevent shortage of the quantity of light required for recording, and the subsequent failure in recording. Here, in the present embodiment, the light-quantity detection device is constituted by the lens 14, the light-source light-quantity controlling light detector 15 and the light-source light-quantity controlling opening 17H; however, the lens 14 may be omitted without causing any problems. EMBODIMENT 2 Next, referring to Figures, the following description will discuss embodiment 2 of the present invention. The present embodiment is different from the above-mentioned embodiment 1 only in that the position and the size of the opening of the light-source light-quantity controlling opening 17H are different from those of embodiment 1, and the other arrangements are the same as those of embodiment 1. Those parts in the present embodiment are same as those of embodiment 1, unless otherwise indicated, and those parts indicated by the same reference numerals as embodiment 1 have the same functions as those of embodiment 1, unless otherwise indicated. FIG. 2 is a block diagram showing an optical head in accordance with embodiment 2 of the present invention. In this case, the lens 14 is placed at a position having a length of light path from the spherical aberration correcting device that is shorter than the length of light path from the spherical aberration correcting device to the objective-lens-use opening 16H. Moreover, the light-source light-quantity controlling opening 17H is placed between the lens 14 and the light-source light-quantity controlling light detector 15. Here, since the operations of the optical head are the same as those described in embodiment 1, the description thereof is omitted in this embodiment. Here, referring to FIG. 3, the following description will discuss the reason why the quantity of light becomes constant when an opening is formed in converging light rays. FIG. 3 shows which light paths light rays that have been made incident on the spherical aberration correcting device are allowed to pass through to be further made incident on the light-source light-quantity controlling light detector 15; and a solid line shows a light path obtained when spherical aberration that occurs in the case of a thick (thicker than a standard value) base-substrate thickness of the optical recording medium is corrected by the spherical aberration correcting device, and a imaginary line shows a light path obtained when spherical aberration that occurs in the case of a thin (thinner than the standard value) base-substrate thickness of the optical recording medium is corrected by the spherical aberration correcting device. As indicated by FIG. 3, when the light-source light-quantity controlling opening 17H is placed between the lens 14 and the spherical aberration correcting device, the quantity of light that is made incident on the light-source light-quantity controlling light detector 15 is varied in response to the distance between the concave lens 5 and the convex lens 6. In this case, however, when the light-source light-quantity controlling opening 17H is placed at a position (B) at which the solid line intersects the imaginary line in the converging light between the lens 14 and the light-source light-quantity controlling light detector 15, it is possible to allow the same quantity of light to be made incident on the light-source light-quantity controlling light detector 15, whichever spherical aberration is corrected. In other words, placing the light-source light-quantity controlling opening 17H in the converging light is the same as placing it at a position that has the equivalent length of light path from the spherical aberration correcting device to the objective-lens-use opening 16H. With this arrangement, in the same manner as described in embodiment 1, even when the spherical aberration correcting device is driven, the signal to be detected by the light detector is only related to variations in the quantity of light to be released from the light source 1; thus, it becomes possible to detect a signal by which the light source 1 is controlled more appropriately. Moreover, in the present embodiment, even in the case when, depending on the structure of the spherical aberration correcting device, even with a constant quantity of light released from the light source 1, the quantity of light released from the objective lens is varied due to variations in the distance of the lenses constituting the spherical aberration correcting device, the signal to be released from the light-quantity detection device is allowed to have completely the same variations; thus, by controlling the signal to be released from the light-quantity detection device to have a constant signal, it is possible to make the quantity of light released from the objective lens constant, and consequently to provide an efficient structure. Moreover, since the light-source light-quantity controlling opening 17H is placed in the converging light in the present embodiment, it is possible to shorten the distance from the spherical aberration correcting device to the light-source light-quantity controlling opening 17H, and consequently to effectively miniaturize the optical head. As described above, with the arrangement in which the light-source light-quantity controlling opening 17H is placed in the converging light in the light-quantity detection device, it becomes possible to set the quantity of light to be released from the objective lens to a desired value, independent of environmental changes such as temperature changes, even while the spherical aberration correcting device is driven; therefore, it is possible to prevent recorded information from being erroneously erased upon reproduction, and it is also possible to prevent a signal to be released from the objective lens from becoming too small to make the subsequent reproduced signal and control signal too small; thus, it becomes possible to prevent the subsequent failure in the reproducing operation and unstable controlling operations. It is also possible to prevent shortage of the quantity of light required for recording, and the subsequent failure in recording. Moreover, since the distance from the spherical aberration correcting device to the light-source light-quantity controlling opening 17H is shortened, it is possible to effectively miniaturize the optical head. Here, in embodiments 1 and 2, the member 17 having the light-source light-quantity controlling opening 17 is compatibly formed by a member that holds the lens 14; however, another member may be used without causing any problems. EMBODIMENT 3 Next, referring to Figures, the following description will discuss embodiment 3 of the present invention. The present embodiment is different from the above-mentioned embodiments 1 and 2 only in that a light separation device that separates light to be made incident on the light quantity detection device constituted by the lens 14 and the light-source light-quantity controlling light detector 15 is placed between the light source and the spherical aberration correcting device so that characteristics of the polarized beam splitter and the mirror are different from those of the above-mentioned embodiments; and the other arrangements are the same as those of embodiment 1. Therefore, those parts in the present embodiment are same as those of embodiment 1, unless otherwise indicated, and those parts indicated by the same reference numerals as the embodiment 1 have the same functions as those of embodiment 1, unless otherwise indicated. FIG. 4 is a block diagram showing an optical head in accordance with embodiment 3 of the present invention. Here, reference numeral 41 is a polarized beam splitter, and reference numeral 42 is a mirror. With respect to linearly polarized light having a certain polarizing direction, the polarized beam splitter 41 transmits 95% thereof, while reflecting 5% thereof, and with respect to linearly polarized light orthogonal to the above-mentioned linearly polarized light, reflects 100% thereof, and the mirror 42 reflects 100% thereof irrespective of directions of polarized lights. Moreover, the light quantity detection device, constituted by the lens 14 and the light-source light-quantity controlling light detector 15, is designed to use reflected light derived from the forward path of the polarized beam splitter 41. Here, the light separation device is formed by the polarized beam splitter 41. The following description will discuss operations of the optical head having the above-mentioned arrangement. Linearly polarized light, released from the light source 1, is divided into three beams by the diffraction grating 2, and the three divided light beams are converted to parallel light rays by the collimator lens 3. With respect to the light converted into the parallel light rays, only one portion thereof is reflected from the polarized beam splitter 41, with most of it being allowed to transmit. The transmitted light is made incident on the spherical aberration correcting device. In this case, in order to correct spherical aberration that occurs when the base-substrate thickness deviates from a standard base-substrate thickness, the incident parallel light rays are converted to diverging light and converging light by changing the distance between the concave lens 5 and the convex lens 6 that constitute the spherical aberration correcting device; thus, the converted light is made incident on the mirror 42 and all the light is reflected, and changed in its advancing direction to the optical recording medium 10. This reflected light is made incident on the ¼ wavelength plate 8 to be converted from linearly polarized light to circularly polarized light; thus, this circularly polarized light is aperture-controlled by the objective-lens-use opening 16H, and made incident on the objective lens 9 so that spherical aberration is generated in proportion to a degree of divergence or a degree of convergence of the incident light, and is further converged on the optical recording medium 10. Here, since light having wave aberration capable of correcting the wave aberration occurring upon deviation in the base-substrate thickness of the optical recording medium 10 from the standard value is converged thereon by the objective lens 9, a light spot that is free from aberration, that is, a light spot that is limited to the diffraction limit, is formed on the optical recording medium 10. Next, the circularly polarized light, reflected from the optical recording medium 10, is inputted to the ¼ wavelength plate 8, and converted to linearly polarized light in a direction orthogonal to the linearly polarized light released from the light source 1. The linearly polarized light converted by the ¼ wavelength plate 8 is all reflected by the mirror 7, allowed to pass through the spherical aberration correcting device, and reflected by the polarized beam splitter 41 and further converged by the condenser lens 11 without returning to the light source 1 so that astigmatism is given to the light by the cylindrical lens 12, and the resulting light is converged on the light detector 13. The light detector 13 outputs a focus error signal that indicates the focused state of light on the optical recording medium 10, and also outputs a tracking error signal that indicates the irradiation position of light. Here, the focus error signal and the tracking error signal are detected by known techniques such as an astigmatism method and a three beam method. Based upon the focus error signal, a focus control device, not shown, controls the position of the objective lens 9 in the light axis direction so that the light is always converged on the optical recording medium 10 in the focused state. Moreover, based upon the tracking error signal, a tracking control device, not shown, controls the position of the objective lens 9 so that light is converged on a desired track on the optical recording medium 10. Furthermore, information recorded on the optical recording medium 10 is also obtained by the light detector 13. Moreover, a portion of the light in the forward path, reflected by the polarized beam splitter 41, is converged on the light-source light-quantity controlling light detector 15 by the lens 14, and the light-source light-quantity controlling light detector 15 outputs an electric signal corresponding to the quantity of light released from the light source 1. As described in the present embodiment, when the light separation device, which makes light incident on the light quantity detection device (constituted by the lens 14 and the light-source light-quantity controlling light detector 15), is placed between the spherical aberration correcting device (provided with the concave lens 5 and the convex lens 6) and the light source, the light to be used in the light quantity detection device is not varied even when the spherical aberration correcting device is driven; therefore, it is possible to positively detect the signal corresponding to the quantity of light released from the light source 1, and by controlling the light source 1 using the signal, it is possible to make the quantity of light released from the objective lens constant. As described above, with the arrangement in which the light quantity detection device is placed between the spherical aberration correcting device and the light source, it becomes possible to set the quantity of light to be released from the objective lens to a desired value, independent of environmental changes such as temperature changes, even while the spherical aberration correcting device is driven; therefore, it is possible to prevent recorded information from being erroneously erased upon reproduction, and it is also possible to prevent a signal to be released from the objective lens from becoming too small to make the subsequent reproduced signal and control signal too small; thus, it becomes possible to prevent the subsequent failure in the reproducing operation and unstable controlling operations. It is also possible to prevent shortage of the quantity of light required for recording, and the subsequent failure in recording. Here, in the present embodiment, the light amount detection device is constituted by the lens 14 and the light-source light-quantity controlling light detector 15; however, the lens 14 may be omitted without causing any problems. Moreover, embodiments 1 and 2 use a system in which a concave lens and a convex lens are used as the spherical aberration correcting device; however, these may be replaced by a group of positive lenses and a group of negative lenses. FIG. 5 is a schematic drawing that shows a spherical aberration correcting device (in which a uniaxial actuator is not shown) provided with a group of negative lenses 51 having a negative power and a group of positive lenses 52 having a positive power. Since the respective groups of the lenses are formed by glass materials having mutually different Abbe numbers, it is possible to provide a spherical aberration correcting device capable of correcting color aberration generated by the lenses forming the optical head, that is, in particular, objective lenses. Moreover, in the system using lenses, it becomes possible to correct spherical aberration in both of the forward path and return path, and consequently to provide a stable reproduced signal and control signal. Moreover, another system using no lenses in the spherical aberration correcting device may be adopted. For example, a system using a phase change layer, disclosed in Japanese Patent Laid-open Publication No. 2002-109776 (Japanese Patent Application No. 2001-221927), may be used. The following description briefly discusses an optical element used in this system. FIG. 6 is a cross-sectional view that shows an optical element using liquid crystal, which serves as a phase change layer, and FIG. 7 shows a pattern used in the optical element. In FIG. 6, reference numeral 61 is a first substrate, reference numeral 62 is a second substrate that is placed virtually in parallel with the first substrate 61, reference numeral 63 is a voltage-applying electrode placed between the first substrate 61 and liquid crystal 67, reference numeral 64 is an opposing electrode that is placed virtually in parallel with the voltage-applying electrode so as to face the voltage-applying electrode 63, reference numeral 65 is a translucent resin film that is formed so as to cover the voltage-applying electrode 63, reference numeral 66 is a translucent resin film formed so as to cover the opposing electrode 64, reference numeral 67 is liquid crystal that is placed between the translucent resin films 65 and 66 (between the voltage-applying electrode 63 and the opposing electrode 64) and reference numeral 68 is a sealing resin that is placed between the translucent resin films 65 and 66 in a manner so as to enclose the liquid crystal 67. Here, the first substrate 61 and the second substrate 62 are made from, for example, glass, and have a translucent property. Moreover, the voltage-applying electrode 63 is an electrode that is used for applying a desired voltage to the liquid crystal 67. The voltage-applying electrode 63 is formed on a main surface inside (on the liquid crystal 67 side) the first substrate 61. Further, the opposing electrode 64 serves as an electrode that is used for applying a desired voltage to the liquid crystal 67, together with the voltage-applying electrode 63. The opposing electrode 64 is formed on a main surface inside (on the liquid crystal 67 side) the second substrate 62. The opposing electrode 64 has a translucent property, and is made from, for example, ITO. Here, the opposing electrode 64 is virtually uniformly formed at least on a portion of the main surface inside the second substrate 62 that faces the segment electrode. Moreover, the translucent resin films 65 and 66, which are alignment films used for aligning the liquid crystal 67 in a predetermined direction, are made of, for example, polyvinyl alcohol films. The translucent resin film 65 or 66 is subjected to a rubbing treatment so that the liquid crystal 67 is aligned in a predetermined direction. Moreover, the liquid crystal 67 functions as a phase change layer that changes the phase of incident light. The liquid crystal 67 is made from, for example, nematic liquid crystal. By changing the voltage difference between the voltage-applying electrode 63 and the opposing electrode 64, it is possible to change the refractive index of the liquid crystal 67, and consequently to change the phase of incident light. Moreover, the sealing resin 68, which is used for sealing the liquid crystal 67, is made from, for example, epoxy resin. As shown in FIG. 7, the voltage-applying electrode 63 is constituted by segment electrodes in the form of concentric circles. These segment electrodes are translucent, and made from, for example, ITO. The following description will discuss operations of the optical element having the above-mentioned arrangement. Control voltages are externally applied to the respective segment electrodes of the voltage-applying electrode of the optical element so as to apply phases of power components to incident light onto the optical element of the present invention. This arrangement makes it possible to convert incident plane waves to spherical waves, and the resulting spherical waves are made incident on the objective lens to generate spherical aberration so that this spherical aberration is used for correcting spherical aberration that occurs when the thickness of the optical recording medium deviates from the designed (standard) base-substrate thickness. Here, the liquid crystal, which has a change in the refractive index in response to voltage, is used as the phase change layer; however, PLZT (transparent crystal substance of the perovskites structure including tin oxide, lanthanum, zirconia or titania), which has a change in thickness (volume) in response to voltage, may be used. Here, since PLZT is a solid, different from the liquid crystal, neither substrate nor sealing resin is required so that it is possible to make the optical element thinner. In the case of the methods described in embodiments 1 and 2, since the lens is used, it is possible to correct aberration derived from the base-substrate thickness of the optical recording medium, of course, in the forward path, as well as in the return path, and consequently to provide a stable control signal. Moreover, in the above-mentioned system, since aberration derived from the base-substrate thickness of the optical recording medium is corrected by using the optical element using the phase change layer, this system is suitable for miniaturization of the optical head. Since any of the lens system and the above-mentioned system using the phase change layer can correct the spherical aberration by using converging light and diverging light, there is no degradation in the spherical aberration correcting function even when the objective lens is shifted. In the above-described embodiment, the spherical aberration correcting device is constituted by a concave lens, a convex lens and a lens position changing mechanism (not shown in the drawings) for changing the distance between the both lenses, however the spherical aberration correcting device may be constituted, without using such a concave lens and a convex lens, by arranging to change the position of the collimator lens. Also, in the above-mentioned embodiments, a single lens is used; however, set lenses, which have a higher NA, may also be used without causing any problems. Further, in the above-mentioned embodiments, an optical head of an infinite type is used; however, an optical head of a finite type without using a collimator lens may be adopted. Moreover, in the above-mentioned embodiments, an optical head of a polarization optical system is used; however, an optical head of a non-polarization optical system may be used. The above-mentioned embodiments have not discussed the method for detecting deviations in the base-substrate thickness from the standard base-substrate thickness of the optical recording medium; however, these can be detected by using a preliminarily determined learning method before a recording or reproducing operation of the optical recording medium. Moreover, another method has been disclosed in Japanese Patent Laid-open Publication No. 2000-171346. In this method, spherical aberration is detected based upon two focal positions derived from a first light beam on the side closer to the light axis of light reflected from the optical recording medium and a second light beam located outside the first light beam. Furthermore, still another method has been disclosed in Japanese Patent Laid-open Publication No. 10-334575. Specifically, in this method, a light source, a first optical system that applies light released from the light source to an optical recording medium (an object to be measured) and a second optical system that directs light reflected from the optical recording medium to a light-receiving element. Here, the light source is formed by a laser, an LED or a lamp, and each of the first and second optical systems is constituted by convex lenses or a combination of convex lenses and concave lenses. With this arrangement, a different signal is released from the light-receiving element depending on the base-substrate thickness so that the signal corresponding to the base-substrate thickness is obtained. Moreover, when the NA of the objective lens exceeds 0.7, the quantity of generated aberration corresponding to the base-substrate deviation from the optimum base-substrate thickness of the optical recording medium becomes greater with the result that the aberration margin for recording is narrowed; thus, a spherical aberration correcting device is required and the present invention is effectively applied. Furthermore, the present invention is more advantageous when the NA of the objective lens 9 is 0.6 or more. This fact will be explained in detail. Actually, the allowance for aberration in manufacturing lens 9 becomes strict according to the NA of the objective lens 9. In forming the objective lens 9, at least 5 μm of decenter between a first surface and a second surface of the objective lens 9 is generated. FIG. 12 is a graph showing a relationship between the NA of the objective lens 9 and amount of generated coma aberration when 5 μm of decenter between a first surface and a second surface of the objective lens 9 is generated. As is well known from FIG. 12, when the NA becomes greater than 0.6, a coma aberration by the decenter is generated. Furthermore, in considering the other tolerance, in the case of the objective lens 9 having the NA greater than 0.6, considerable aberration is generated by the tolerance in manufacturing. Accordingly, in the case of the objective lens 9 having the NA greater than 0.6, the amount of generated aberration due to the deviation in the base-substrate thickness of the optical recording medium becomes significant. Therefore, the present invention is more advantageous when the NA of the objective lens 9 is 0.6 or more. In the same manner, when the wavelength becomes very short, such as a level of not more than 450 nm, the quantity of generated aberration corresponding to the base-substrate deviation becomes greater with the result that the aberration margin for recording is narrowed; thus, a spherical aberration correcting device is required and the present invention is effectively applied. In the above-described embodiments, the member 16 having the objective-lens-opening 16H and the member 17 having the light-source light-quantity controlling opening 17H are constituted by members for holding lens respectively. However, they may be provided directly on the basic pedestal of the optical head. In this case, since the number of parts can be reduced, it is possible to reduce the manufacturing cost and miniaturize the optical head. Further, in the above-described embodiments, the light passed through the mirror 7 is made incident on the light-source light-quantity controlling light detector 15 by means of the lens 14. However, the light passed through the mirror 7 may be made incident directly on the light-source light-quantity controlling light detector 15, by omitting the lens 14, without any problems. EMBODIMENT 4 Embodiment 4 discusses one example of an optical recording/reproducing apparatus in accordance with the present invention. The optical recording/reproducing apparatus of embodiment 4 is an apparatus that carries out recording and reproducing operations of a signal on and from an optical recording medium. FIG. 8 schematically shows a structure of an optical recording/reproducing apparatus 80 of embodiment 4. The optical recording/reproducing apparatus 80 is provided with an optical head 81, a motor 82 and a processing circuit 83. The optical head 81 has been described in embodiment 1. Since the optical head 81 has the same structure as that explained in embodiment 1, the overlapping description thereof is omitted. The following description discusses operations of the optical recording/reproducing apparatus 80. First, when an optical recording medium 10 is set on the optical recording/reproducing apparatus 80, the processing circuit 83 outputs a signal so as to rotate the motor 82 so that the motor 82 is allowed to rotate. Next, the processing circuit 83 drives the light source 1 to release light. The light released from the light source 1 is reflected by the optical recording medium 10, and the reflected light is made incident on the light detector 13. The light detector 13 outputs a focus error signal that indicates the focused state of the light on the optical recording medium 10 and a tracking error signal that indicates an irradiation position of light to the processing circuit 83. Based upon these signals, the processing circuit 83 outputs a signal for controlling the objective lens 9 so that the light, released from the light source 1, is converged on a desired track on the optical recording medium 10. Moreover, based upon a signal outputted from the light detector 13, the processing circuit 83 reproduces information recorded on the optical recording medium 10. Moreover, the signal, outputted from the light-source light-quantity controlling light detector 15, is inputted to the processing circuit 83; thus, the processing circuit 83 controls the light source 1 to set the signal to a desired value so that the quantity of light released from the objective lens 9 is set to a desired value. As described above, since this apparatus uses the optical head of embodiment 1 as its optical head, the objective lens is allowed to output a desired quantity of light even when the spherical aberration correcting device is driven; thus, it becomes possible to obtain a stable control signal and reproduced signal, and consequently to carry out a stable recording operation. The embodiments of the invention being thus described by device of examples, it will be obvious that not limited to the above-mentioned embodiments, the same may be applied to other embodiments based upon the technical idea of the present invention. Moreover, the above-mentioned embodiments have discussed the optical recording medium for recording information by using only light; however, the present invention may of course be applied to optical recording media for recording information by using light and magnetism, with the same effects. Furthermore, the above-mentioned embodiments have discussed the case in which the optical recording medium is an optical disk; however, the present invention may be applied to optical information recording/reproducing apparatuses that have similar functions, such as card-shaped optical recording media. As described above, in accordance with the present invention, in the case when the light quantity detection device is placed between the spherical aberration correcting device and the light source or when the light quantity detection device is placed between the spherical aberration correcting device and the optical recording medium, by setting the position of the light-source light-quantity controlling opening that forms the light quantity detection device at a position corresponding to an optical light path length from the spherical aberration correcting device to the objective-lens-use opening or at a desired position in the converging light of the light quantity detection device, the signal to be outputted from the light quantity detection device is allowed to correspond to only the quantity of light outputted from the light source even when the spherical aberration correcting device is driven; thus; when the light source 1 is controlled by using the above-mentioned signal, it becomes possible to set the quantity of light to be outputted from the objective lens to a desired value, and consequently to provide stable reproducing and recording operations. Moreover, by using the above-mentioned optical head, it is possible to obtain a stable control signal and reproduced signal even when the spherical aberration correcting device is driven, and consequently to achieve an optical recording/reproducing apparatus capable of carrying out a stable recording operation. The present disclosure relates to subject matter contained in Japanese Application No. 2003-102609, filed on Apr. 7, 2003, the contents of which are herein expressly incorporated by reference in its entirety. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to an optical head used in optical information processing, optical communication or the like and an optical recording and reproducing apparatus using the optical head. 2. Description of the Related Art Recently, a digital versatile disc (DVD) has attracted attention as a high-capacity optical recording medium because it can record digital information in a recording density which is about 6 times as high as a compact disc (CD). However, a further high-density optical recording medium is demanded as capacity of information becomes large. Here, in order to realize a density higher than the DVD (wavelength is 660 nm and numerical aperture (NA) is 0.6), it is necessary to use a light source emitting a light having shorter wavelength and to further increase the NA of the objective lens. For example, when blue laser having a wavelength of 405 nm and an objective lens having NA of 0.85 are used, a recording density which is 5 times as high as the DVD can be attained. However, since the high-density optical recording medium apparatus using the blue laser has very strict reproducing and/or recording margin, in other words, a permissible level for a fluctuation of characteristic in reproducing or recording is limited very strictly, aberration generated by a fluctuation in the base-substrate thickness of an optical recording medium becomes a problem. It is to be noted that the wording “reproducing and/or recording” means “at least one of reproducing and recording”, in the specification, to simplify the description. In relating to this problem, Japanese Patent Laid-open Publication No. 2000-131603 discloses an optical head which aims to carry out reproducing and recording operations while correcting aberration due to a fluctuation in the base-substrate thickness of an optical recording medium. One example of the above conventional optical head is described with reference to the drawing. FIG. 9 is a schematic view showing a constitution of the conventional optical head. In FIG. 9 , reference numeral 91 designates a light source, reference numeral 92 designates a diffraction grating, reference numeral 93 designates is a collimator lens, reference numeral 94 designates a polarized beam splitter, reference numeral 95 designates a ¼ wavelength plate, reference numeral 96 designates a group of aberration correcting lenses, reference numeral 97 designates an objective lens, reference numeral 98 designates an optical recording medium, reference numeral 99 designates a focusing lens, reference numeral 100 designates a multi-lens and reference numeral 101 designates a light detector. The light source 91 , which is a semiconductor laser, serves as a light source that outputs coherent light for use in recording and reproducing to a recording layer of the optical recording medium 98 . The diffraction grating 92 has a structure in which a concave/convex pattern is formed on a surface of a glass substrate, and serves an optical element which divides an incident beam into three beams so as to allow detection of a tracking error signal through a so-called three beam method. The collimator lens 93 is a lens which converts diverged light emitted from the light source 91 to parallel light rays. The polarized beam splitter 94 is an optical element which has different transmittance and reflection factor depending on incident polarized light, and is used for separating light. The ¼ wavelength plate 95 is made from a birefringence material, and serves as an optical element that converts linearly polarized light to circularly polarized light. The group of aberration correcting lenses 96 , which is used for correcting spherical aberration that occurs when the base-substrate thickness of the optical recording medium 98 is different from a predetermined standard value, is constituted by a group of concave lenses 96 a and a group of convex lenses 96 b as well as a uniaxial actuator, not shown. And, by changing the distance between the group of concave lenses 96 a and the group of convex lenses 96 b , it becomes possible to correct the spherical aberration. The above-mentioned standard value is, more preferably, determined based on an optimum design base-substrate thickness as a thickness of the base-substrate of the optical recording medium 98 . The group of aberration correcting lenses 96 will be described later in detail The objective lens 97 is a lens for converging light on a recording layer of the optical recording medium 98 . The focusing lens 99 is a lens used for converging light reflected from the recording layer of the optical medium 98 onto the light detector 101 . The multi-lens 100 has a cylindrical surface as its light incident face, and its light-releasing face forms a rotation symmetrical face with respect to the lens light axis so that astigmatism, which allows the detection of a focus error signal with respect to incident light through a so-called astigmatism method, is given. The light detector 101 receives light reflected by the recording layer of the optical recording medium 98 to convert the light to an electric signal. The following description will discuss operations of the optical head having the above-mentioned arrangement. Linearly polarized light, emitted from the light source 91 , is divided into three beams by the diffraction grating 92 , and the three divided light beams are converted to parallel light rays by the collimator lens 93 . The resulting parallel light rays are allowed to pass through the polarized beam splitter 94 , and made incident on the ¼ wavelength plate 95 so that the linearly polarized light is converted into circularly polarized light. The circularly polarized light that has passed through the ¼ wavelength plate 95 is made incident on the group of aberration correcting lenses 96 . In this case, in order to correct spherical aberration that occurs when the base-substrate thickness of the optical recording medium 98 deviates from an standard thickness, the incident parallel light rays are converted to diverging light and converging light by changing the distance between the group of concave lenses 96 a and the group of convex lenses 96 b that constitute the group of aberration correcting lenses 96 . Then, the converted light is made incident on the objective lens 97 so that spherical aberration is generated in proportion to a degree of divergence or a degree of convergence of the incident light, and is converged on the optical recording medium 98 . Here, since light having wave aberration capable of correcting the wave aberration occurring upon deviation in the base-substrate thickness of the optical recording medium 98 from the standard base-substrate thickness is converged thereon by the objective lens 97 , a light spot that is free from aberration, that is, a light spot that is limited to the diffraction limit, is formed on the optical recording medium 98 . Next, the circularly polarized light, reflected from the optical recording medium 98 , is allowed to pass through the group of aberration correcting lenses 96 , and is input to the ¼ wavelength plate 95 , then is converted to linearly polarized light in a direction orthogonal to the linearly polarized light that has been emitted from the light source 91 . The linearly polarized light, converted by the ¼ wavelength plate 95 , is reflected by the polarized beam splitter 94 , and converged by the focusing lens 99 without returning to the light source 91 so that astigmatism is given to the light made incident by the multi-lens 100 and the resulting light is converged on the light detector 101 . The light detector 101 outputs a focus error signal that indicates a focused state of light on the optical recording medium 98 , and also outputs a tracking error signal that indicates an irradiation position of light. Here, the focus error signal and the tracking error signal are detected by known techniques such as an astigmatism method and a three beam method. Based upon the focus error signal, a focus control device, not shown, controls the position of the objective lens 97 in the light axis direction so that the light is always converged on the optical recording medium 98 in the focused state. Moreover, based upon the tracking error signal, a tracking control device, not shown, controls the position of the objective lens 97 so that light is converged on a desired track on the optical recording medium 98 . Furthermore, information recorded on the optical recording medium 98 is also obtained by the light detector 101 . Here, the following description will discuss the spherical aberration correcting operation that is available by the use of the group of aberration correcting lenses 96 , in detail. When the distance between the group of concave lenses 96 a and the group of convex lenses 96 b constituting the group of aberration correcting lenses 96 is narrowed, the parallel light rays are converted to diverging light, and when the distance is widened, the parallel light rays are converted to converging light. In other words, by changing the distance between the group of concave lenses 96 a and the group of convex lenses 96 b , it is possible to generate light rays having power components with different codes. Here, in the case when light having a power component is made incident on the objective lens 97 , spherical aberration occurs in the light converged by the objective lens 97 , and since the code is dependent on the code of the incident power component, it is possible to correct the spherical aberration that occurs upon deviation of the base-substrate thickness of the optical recording medium 98 from a standard base-substrate thickness by using this spherical aberration. With this arrangement, since the spherical aberration caused by the deviation in the base-substrate thickness of the optical recording medium 98 can be corrected by using the group of aberration correcting lenses 96 , it is possible to carry out stable reproducing and recording operations. In the optical head having the above-mentioned conventional arrangement, however, no description has been given to a light-quantity detection device that is required to control the quantity of light released from the light source 91 , with the result that a problem arises due to the position of this light-quantity detection device. Referring to FIG. 10 , the following description discusses this problem in detail. Here, only the points in which an optical head shown in FIG. 10 is different from the optical head of FIG. 9 are that a mirror and a light-quantity detection device are further installed and that the ¼ wavelength plate is placed between the mirror and the objective lens; except for these points, it has the same arrangement as the optical head of FIG. 9 . Therefore, in FIG. 10 , the same parts as those of the optical head of FIG. 9 are used, unless otherwise indicated, and those components indicated by the same reference numerals have the same functions, unless otherwise indicated. In FIG. 10 , reference numeral 201 is a mirror, reference numeral 202 is a condenser lens and reference numeral 203 is a light-source light-quantity controlling light detector. Here, the light-quantity detection device is constituted by the condenser lens 202 and the light-quantity controlling light detector 203 . The mirror 201 is an optical element that reflects incident light to direct the resulting light to the optical recording medium 98 , and with respect to certain linearly polarized light, transmits 5% thereof, while reflecting 95% thereof, and with respect to linearly polarized light orthogonal to the above-mentioned linearly polarized light, reflects 100% thereof. The following description will discuss operations of the optical head having the above-mentioned arrangement. Linearly polarized light, released from the light source 91 , is divided into three beams by the diffraction grating 92 , and the three divided light beams are converted to parallel light rays by the collimator lens 93 . The light, converted into the parallel light rays, are allowed to pass through the polarized beam splitter 94 , and made incident on the group of aberration correcting lenses 96 . In this case, in order to correct spherical aberration that occurs when the base-substrate thickness deviates from a standard value, the incident parallel light rays are converted to diverging light and converging light by changing the distance between the group of concave lenses 96 a and the group of convex lenses 96 b that constitute the group of aberration correcting lenses 96 ; thus, the converted light is made incident on the mirror 201 so that one portion (5%) thereof is allowed to transmit, while most (95%) of it is reflected, and changed in its advancing direction to the optical recording medium 98 . This reflected light is made incident on the ¼ wavelength plate 95 to be converted from linearly polarized light to circularly polarized light; thus, this circularly polarized light is made incident on the objective lens 97 so that spherical aberration is generated in proportion to a degree of divergence or a degree of convergence of the incident light, and is further converged on the optical recording medium 98 . Here, since light having wave aberration capable of correcting the wave aberration occurring upon deviation in the bas-substrate thickness of the optical recording medium 98 from the standard thickness is converged thereon by the objective lens 97 , a light spot that is free from aberration, that is, a light spot that is limited to the diffraction limit, is formed on the optical recording medium 98 . Next, the circularly polarized light, reflected from the optical recording medium 98 , is inputted to the ¼ wavelength plate 95 , and converted to linearly polarized light in a direction orthogonal to the linearly polarized light released from the light source 91 . The linearly polarized light converted by the ¼ wavelength plate 95 is all reflected by the mirror 201 , allowed to pass through the group of aberration correcting lenses 96 , and reflected by the polarized beam splitter 94 and further converged by the focusing lens 99 without returning to the light source 91 so that astigmatism is given to the light made incident by the multi-lens 100 and the resulting light is converged on the light detector 101 . The light detector 101 outputs a focus error signal that indicates a focused state of light on the optical recording medium 98 , and also outputs a tracking error signal that indicates an irradiation position of light. Here, the focus error signal and the tracking error signal are detected by known techniques such as an astigmatism method and a three beam method. Based upon the focus error signal, a focus control device, not shown, controls the position of the objective lens 97 in the light axis direction so that the light is always converged on the optical recording medium 98 in the focused state. Moreover, based upon the tracking error signal, a tracking control device, not shown, controls the position of the objective lens 97 so that light is converged on a desired track on the optical recording medium 98 . Furthermore, information recorded on the optical recording medium 98 is also obtained by the light detector 101 . Moreover, the light that has passed through the mirror 201 is converged on the light-source light-quantity controlling light detector 203 by the condenser lens 202 , and the light-source light-quantity controlling light detector 203 outputs an electric signal corresponding to the quantity of light released from the light source 1 . The necessity of the above-mentioned light-quantity detection device is explained as follows: Since the light source 91 is formed by a semiconductor laser, the light source 91 has a temperature rise when it continues to output light, with the result that the quantity of light to be outputted from the light source 91 tends to vary even when the current used for controlling the light source 91 is constant. Therefore, by detecting one portion of the light released from the light source 91 , it becomes possible to control the quantity of light released from the light source 91 . However, in the case when the signal detected by the light-quantity detection device is varied independent of the quantity of light from the light source 91 , a serious problem is raised. For example, even in the case of constant quantity of light from the light source 91 , when the signal outputted from the light quantity detection device becomes smaller, the light source 91 is controlled so as to release a greater quantity of light, with the result that a great quantity of light is released during a reproducing operation of the optical recording medium 98 to cause erroneous erasing of information recorded in the optical recording medium 98 . In contrast, even in the case of constant quantity of light from the light source 91 , when the signal outputted from the light quantity detection device becomes greater, the light source 91 is controlled so as to release a smaller quantity of light, with the result that the quantity of light fails to reach a sufficient quantity required for recording during a recording operation on the optical recording medium 98 to cause an insufficient recording process. In other words, a serious problem is raised unless the signal detected by the light-quantity detection device varies in response to the quantity of light released from the light source 91 . FIG. 11 schematically shows light to be made incident on the objective lens 97 when the group of aberration correcting lenses 96 is driven to correct spherical aberration. In FIG. 11 , in the case when the base-substrate thickness of the optical recording medium 98 is thicker than a standard thickness, the distance between the group of concave lenses 96 a and the group of convex lenses 96 b becomes wider so that the light is made incident on the objective lens 97 as converged light. This state is indicated by a solid line. In the case when the base-substrate thickness of the optical recording medium 98 is thinner than the standard base-substrate thickness, the distance between the group of concave lenses 96 a and the group of convex lenses 96 b becomes smaller so that the light is made incident on the objective lens 97 as diverged light. This state is indicated by an imaginary line. Here, it is supposed that the light to be used in the light-quantity detection device is located at position A in FIG. 11 . In FIG. 10 , an aperture (not shown), which is used for controlling the quantity of transmitted light, is formed between the mirror 201 and the condenser lens 202 , and this is schematically indicated as an aperture 110 H (opening) in FIG. 11 . This aperture 110 H is provided by forming a hole (opening) in a plate member 110 . The member 110 having aperture 110 H may be a hold member for holding the group of convex lenses 96 b. As shown by FIG. 11 , although the group of aberration correcting lenses is designed so as to make the quantity of incident light onto the objective lens 97 constant independent of the location of the group of concave lenses 96 a while the group of concave lenses 96 a is shifted to correct spherical aberration, the light to be made incident on the light-source light-quantity controlling light detector 203 is shield by the member 110 having the aperture 110 H on the peripheral portion thereof depending on the position of the group of concave lenses 96 a , with the result that the quantity of light to be detected by the light-source light-quantity controlling light detector 203 is varied. In other words, although the quantity of light of the light source 91 is not changed, the quantity of light to be made incident on the light-source light-quantity controlling light detector 203 is varied, as described above, with the result that a signal is outputted as if it were derived from a change in the quantity of light in the light source; consequently, problems are raised in that recorded information is erased during reproducing, and in that insufficient recording is caused due to a failure in outputting a sufficient quantity of light upon recording. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention has been devised to solve the above-mentioned conventional problems, and its first objective is to provide an optical head in which a signal, outputted from the light-source light-quantity controlling light detector 203 , is only dependent on a quantity of light to be released from the light source even when spherical aberration has been corrected. Moreover, a second objective of the present invention is to provide an optical recording/reproducing apparatus makes it possible to detect a quantity of light to be released from the light source accurately even in the case when there is a deviation from a standard value in the base-substrate thickness of the optical recording medium and spherical aberration caused by the deviation has been corrected, and consequently to carry out stable reproducing and recording operations. In order to achieve the above-mentioned objectives, an optical head of the present invention, which records and/or reproduces a signal on or from an optical recording medium, is provided with: a light source; an objective lens that converges light released from the light source onto the optical recording medium; an objective-lens-use opening that determines an aperture of the objective lens; a spherical aberration correcting device that corrects spherical aberration that occurs when the optical recording medium has a base-substrate thickness that deviates from a standard base-substrate thickness; a light separation device that is placed in a light path from the spherical aberration correcting device to the optical recording medium; a light-source light-quantity controlling opening that aperture-controls light that has been separated by the light separation device; a first light detector that receives light that has been aperture-controlled by the light-source light-quantity controlling opening; and a second light detector that receives light that has been reflected by the optical recording medium, and in this arrangement, a length of the optical light path from the spherical aberration correcting device to the objective-lens-use opening is made substantially the same as a length of the optical light path from the spherical aberration correcting device to the light-source light-quantity controlling opening, and the aperture of the light-source light-quantity controlling opening substantially has the same size as the aperture of the objective-lens-use opening. With this arrangement, even when the spherical aberration correcting device is driven, the signal to be outputted by the first light detector that receives light that has been aperture-controlled by the light-source light-quantity controlling opening is prepared as a signal that corresponds to only the quantity of light released from the light source; thus, since the light source can be controlled by using this signal, it becomes possible to carry out stable reproducing and recording operations. Also, in order to achieve the above-mentioned objectives, another optical head of the present invention, which records and/or reproduces a signal on or from an optical recording medium, is provided with: a light source; an objective lens that converges light released from the light source onto the optical recording medium; a spherical aberration correcting device that corrects spherical aberration that occurs when the optical recording medium has a base-substrate thickness that deviates from a standard base-substrate thickness; a light separation device that is placed in a light path from the spherical aberration correcting device to the optical recording medium; a lens that converges light that has been separated by the light separation device; a light-source light-quantity controlling opening that aperture-controls light that has been converged by the lens; a first light detector that receives light that has been aperture-controlled by the light-source light-quantity controlling opening; and a second light detector that receives light that has been reflected by the optical recording medium. With this arrangement, even when the spherical aberration correcting device is driven, a signal, outputted by the first light detector that receives light that is aperture-controlled by the light-source light-quantity controlling opening, is prepared as a signal that corresponds to only the quantity of light released from the light source; thus, it is possible to control the light source by using this signal, and consequently to carry out stable reproducing and recording operations. Moreover, since the distance from the spherical aberration correcting device to the light detector that receives light that has been aperture-controlled by the light-source light-quantity controlling opening can be shortened, it becomes possible to miniaturize the optical head effectively. In order to achieve the above-mentioned objectives, another optical head of the present invention, which records or reproduces a signal on or from an optical recording medium, is provided with: a light source; an objective lens that converges light released from the light source onto the optical recording medium; a spherical aberration correcting device that corrects spherical aberration that occurs when the optical recording medium has a base-substrate thickness that deviates from a standard base substrate thickness; a light separation device that is placed in a light path from the light source to the spherical aberration correcting devise; a first light detector that receives light that has been separated by the light separation device; and a second light detector that receives light that has been reflected by the optical recording medium. With this arrangement, even when the spherical aberration correcting device is driven, the signal to be outputted by the first light detector that receives light separated by the light separation device is prepared as a signal that corresponds to only the quantity of light released from the light source; thus, it becomes possible to control the light source by using this signal, and consequently to carry out stable reproducing and recording operations. In the above-mentioned optical head, the spherical aberration correcting device is preferable to correct the spherical aberration by the spherical aberration correcting device generates at least one of converging light and diverging light. More specifically, the spherical aberration correcting device is more preferably constituted by a group of positive lenses and a group of negative lenses. With this arrangement, spherical aberration that occurs when the base-substrate thickness of the optical recording medium deviates from the standard base-substrate thickness can be corrected in both of the forward path and return path of the optical head; thus, it becomes possible to obtain a stable control signal and reproducing signal. In the above-mentioned optical head, the spherical aberration correcting device is preferably prepared as an optical element having a phase change layer placed between a pair of substrates having transparent conductive thin films. Since this arrangement allows miniaturization of the spherical aberration correcting device, it becomes possible to miniaturize the optical head effectively. In the above-mentioned optical head, light that is made incident on the phase change layer is converted to diverging light or converging light by the phase change layer. With this arrangement, it is possible to prevent degradation in the spherical aberration correcting function even when the lens is shifted. In the above-mentioned optical head, the optical head is preferably provided with a base-substrate thickness detection device that detects a base substrate thickness of the optical recording medium. Since this arrangement makes it possible to detect a deviation in the base-substrate thickness of the optical recording medium from the standard value at any position on the optical recording medium, it is possible to correct spherical aberration with higher precision, and consequently to obtain a stable control signal and reproduced signal. In the above-mentioned optical head, the base-substrate thickness detection device is preferably provided with: a light source; a lens that converges light released from the light source on the optical recording medium; and a light detector that detects light that has been reflected by the optical recording medium. With this arrangement, since the aberration derived from the base-substrate thickness of the optical recording medium is detected by using another optical system, it is possible to detect the aberration derived from the base-substrate thickness of the optical recording medium simultaneously during a reproducing or recording operation. In the above-mentioned optical head, the base-substrate thickness detection device detects information relating to the base-substrate thickness based upon two focal points of a first light ray on the side closer to a light axis of light and a second light ray on the outside of the first light ray. With this arrangement, it is possible to miniaturize the optical head. In the above-mentioned optical head, the objective lens preferably has an NA of not less than 0.6. With this arrangement, in an attempt to achieve higher density in the case of a small aberration margin with respect to recording and reproducing operations, the optical recording medium is allowed to have an expanded tolerance for the deviation of the base-substrate thickness from the standard value. Therefore, it becomes possible to achieve a higher recording density. In the above-mentioned optical head, the light source preferably has a wavelength of not more than 450 nm. With this arrangement, in an attempt to achieve higher density in the case of a small aberration margin with respect to recording and reproducing operations, the optical recording medium is allowed to have an expanded tolerance for the deviation of the base-substrate thickness from the standard base-substrate thickness. Therefore, it becomes possible to achieve a higher recording density. In order to achieve the above-mentioned objectives, an optical recording/reproducing apparatus, which records and/or reproduces a signal on or from an optical recording medium, is provided with the optical head having the above-mentioned arrangement for recording or reproducing a signal on or from an optical recording medium. This apparatus makes it possible to detect a signal corresponding to the quantity of light released from a light source even when the spherical aberration correcting device is driven, and consequently to control the light source by using this signal; thus, it becomes possible to carry out stable reproducing and recording operations. | 20040406 | 20070807 | 20050317 | 66139.0 | 0 | HINDI, NABIL Z | OPTICAL HEAD AND OPTICAL RECORDING AND REPRODUCING APPARATUS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,817,874 | ACCEPTED | Monopulse radar system | A monopulse radar system aims to correct an amplitude error and a phase error developed between receiving channels and improve the accuracy of a detected angle. To achieve the above aim, part of a transmit signal is supplied to respective channels on the receiving side through a signal transmission line for calibration. At this time, the gains of a variable phase shifter and a variable gain amplifier are adjusted so that an azimuth angle of a pseudo target, based on a signal for calibration, which is calculated by signal processing means, reaches a predetermined angle. Therefore, calibration work is simplified and an angular correction can be automated. Therefore, the present monopulse radar system is capable of coping even with variations in characteristic after product shipment due to environmental variations and time variations in parts characteristic. | 1. A monopulse radar system for radiating a transmit signal from a transmitting antenna and for receiving a signal obtained by allowing the transmit signal to be reflected by a target with two or more receiving antennas to thereby detect the target, comprising: a calibration signal transmission line for supplying the transmit signal to each of the signal transmission lines connected to the two or more receiving antennas as a calibration signal; and a signal processor to adjust an azimuth angle of a pseudo target calculated based on the calibration signal, so as to reach a predetermined angle of the monopulse radar, wherein said signal processor calculates the pseudo target and calculates the azimuth angle of the pseudo target based on the transmit signal as the calibration signal supplied with through the calibration signal transmission line. 2. The monopulse radar system according to claim 1, further comprising a switch to bring the calibration signal transmission line into a conducting state or a cutoff state. 3. The monopulse radar system according to claim 2, further comprising a switch driver to produce the conducting state of said switch on a regular basis or with predetermined timing. 4. The monopulse radar system according to claim 1, further comprising a modulator to modulate the calibration signal with a low frequency signal. 5. The monopulse radar system according to claim 2, further comprising a modulator to modulate the calibration signal with a low frequency signal. 6. The monopulse radar system according to claim 3, further comprising a modulator to modulate the calibration signal with a low frequency signal. 7. The monopulse radar system according to claim 1, wherein said signal processor is provided in correspondence with a channel to effect signal processing on at least one receiving antenna, which includes corrector to correct at least either the phase or amplitude of the calibration signal, and a control signal generating unit to drive the corrector. 8. The monopulse radar system according to claim 2, wherein said signal processor is provided in correspondence with a channel to effect signal processing on at least one receiving antenna, which includes corrector to correct at least either the phase or amplitude of the calibration signal, and a control signal generating unit to drive the corrector. 9. The monopulse radar system according to claim 3, wherein said signal processor is provided in correspondence with a channel to effect signal processing on at least one receiving antenna, which includes corrector to correct at least either the phase or amplitude of the calibration signal, and a control signal generating unit to drive the corrector. 10. The monopulse radar system according to claim 4, wherein said signal processor is provided in correspondence with a channel to effect signal processing on at least one receiving antenna, which includes corrector to correct at least either the phase or amplitude of the calibration signal, and a control signal generating unit to drive the corrector. 11. The monopulse radar system according to claim 5, wherein said signal processor is provided in correspondence with a channel to effect signal processing on at least one receiving antenna, which includes corrector to correct at least either the phase or amplitude of the calibration signal, and a control signal generating unit to drive the corrector. 12. The monopulse radar system according to claim 6, wherein said signal processor is provided in correspondence with a channel to effect signal processing on at least one receiving antenna, which includes corrector to correct at least either the phase or amplitude of the calibration signal, and a control signal generating unit to drive the corrector. 13. The monopulse radar system according to claim 2, wherein said signal processor is configured to bring the switch into a conducting state, to calculate an azimuth angle of a pseudo target which is detected by the calibration signal, and to determine correction data so that the calculated azimuth angle reaches a predetermined angle, and wherein said signal processor further comprises a memory to store the correction data therein; and a corrector to effect an angular correction based on the correction data stored in the memory upon calculation of the azimuth angle of the target. 14. The monopulse radar system according to claim 3, wherein said signal processor is configured to bring the switch into a conducting state, to calculate an azimuth angle of a pseudo target which is detected by the calibration signal, and to determine correction data so that the calculated azimuth angle reaches a predetermined angle, and wherein said signal processor further comprises a memory to store the correction data therein; and a corrector to effect an angular correction based on the correction data stored in the memory upon calculation of the azimuth angle of the target. 15. The monopulse radar system according to claim 5, wherein said signal processor is configured to bring the switch into a conducting state, to calculate an azimuth angle of a pseudo target which is detected by the calibration signal, and to determine correction data so that the calculated azimuth angle reaches a predetermined angle, and wherein said signal processor further comprises a memory to store the correction data therein; and a corrector to effect an angular correction based on the correction data stored in the memory upon calculation of the azimuth angle of the target. 16. The monopulse radar system according to claim 6, wherein said signal processor is configured to bring the switch into a conducting state, to calculate an azimuth angle of a pseudo target which is detected by the calibration signal, and to determine correction data so that the calculated azimuth angle reaches a predetermined angle, and wherein said signal processor further comprises a memory to store the correction data therein; and a corrector to effect an angular correction based on the correction data stored in the memory upon calculation of the azimuth angle of the target. 17. The monopulse radar system according to claim; 1, wherein the calibration signal is supplied to output parts of the two or more receiving antennas at equal power and in equiphase fashion. 18. The monopulse radar system according to claim, 2, wherein the calibration signal is supplied to output parts of the two or more receiving antennas at equal power and in equiphase fashion. 19. The monopulse radar system according to claim 3, wherein the calibration signal is supplied to output parts of the two or more receiving antennas at equal power and in equiphase fashion. 20. The monopulse radar system according to claim 4, wherein the calibration signal is supplied to output parts of the two or more receiving antennas at equal power and in equiphase fashion. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monopulse radar system, and more specifically to a monopulse radar system for radiating a signal from a transmitting antenna, and receiving a signal reflected by a target with a plurality of receiving antennas to thereby detect an angle of an existing position of the target. 2. Description of the Related Art In a radar system, a monopulse system is known as one method of detecting an azimuth angle to a target. The monopulse system radiates a signal from a transmitting antenna and receives a signal reflected by a target through the use of two or more receiving antennas. At this time, information about the angle of the target to the radar system is obtained from the difference in amplitude or phase between the signals received by the individual antennas. In general, one using the phase difference is called a “phase monopulse”, whereas one using the amplitude difference is called an “amplitude monopulse”. As this type of monopulse radar system, a radar system using a phase monopulse has been described in, for example, Japanese Patent Laid-Open No. H11(1999)-271433. The principle of operation of a monopulse radar system will be explained below using FIG. 2. A signal generated from a signal generator OSC1 is radiated or emitted from a transmitting antenna ANT1. The radiated signal is reflected by a target, which in turn is received by two receiving antennas ANT2 and ANT3. The received signals are converted into low frequency signals by mixers MIX1 and MIX2, followed by being subjected to signal analytic processing such as FFT (Fast Fourier Transform) in signal processing means P1. In the case of the phase monopulse, the difference in phase between signals received by two antennas is determined. When the two receiving antennas are laid out with an interval d defined therebetween as shown in FIG. 3, the following equation (1) is established between the difference in phase between signals received by them, and an azimuth angle to a target: Δφ=(2πd/λ)sin θ (1) On the other hand, when the amplitude monopulse is used, directivity S1 of the receiving antenna ANT2 and directivity S2 of the receiving antenna ANT3 are distributed as represented in a gain characteristic of FIG. 4. A signal strength based on the sum of the signals received by the two antennas and a signal strength based on the difference between the signals are respectively represented as gain characteristics shown in FIG. 5. Further determining the ratio between the two from the sum signal and the difference signal results in a gain characteristic R1 of FIG. 6. The magnitude of this ratio and angles are associated with each other to thereby determine each corresponding angle. An in-vehicle radar system often makes use of an ultra-high frequency like a millimeter wave. Frequencies ranging from 76 GHz to 77 GHz are assigned to a vehicle radar used in a vehicle-to-vehicle distance warning system for a vehicle. In general, parts used in such an ultra-high frequency are expensive and large in part-to-parts characteristic variations as compared with parts used in a low frequency. Further, since the wave length is very short in the ultra-high frequency like the millimeter wave, variations in characteristic occur even upon assembly of modules for the radar system. On the other hand, the conventional monopulse radar system shown in FIG. 2 detects a phase difference or an amplitude difference from the low-frequency signals produced by the mixers MIX1 and MIX2 and calculates the azimuth angle of the target, based on it. Thus, it is necessary to grasp whether a channel CH1 based on the receiving antenna ANT2 and a channel CH2 based on the receiving antenna ANT3 coincide in characteristic with each other with very high accuracy, or the difference therebetween in advance. In the radar system using signals lying in a millimeter wave band, however, a phase error or an amplitude error is developed between channels due to the aforementioned reason, and an error is developed in a detected azimuth angle of target. As a countermeasure taken against it, a method of detecting and selecting used parts in advance and using only ones matched in characteristic with each other might be adopted. However, this will result in an increase in part cost. Further, variations developed upon part assembly cannot be eliminated. As another countermeasure, there is known a method of actually radiating a radio wave from the forward of a radar system and correcting a phase difference or an amplitude error developed between channels, based on a detected signal obtained therefrom as has been described in, for example, Japanese Patent Laid-Open No. H5(1993)-232215. In such a method, however, the system becomes large-scale and takes a lot of trouble over its calibration work. Therefore, the manufacturing cost thereof will increase due to the new addition of this work. A problem arises in that any countermeasures referred to above do not take into consideration variations in characteristic after the shipment of each product, and the accuracy of a detected angle is deteriorated where variations in characteristic occur due to some kind of factors such as environmental variations, time variations in parts characteristic. Accordingly, it is a main object of the present invention to provide a monopulse radar system capable of easily correcting a phase error or an amplitude error developed between receiving channels corresponding to a plurality of receiving antennas of the monopulse radar system and reducing a manufacturing cost thereof. It is another object of the present invention to provide a monopulse radar system capable of coping even with characteristic variations after product shipment such as environmental variations, time variations in parts characteristic and correcting a phase error and an amplitude error. BRIEF SUMMARY OF THE INVENTION In order to achieve the above object, a monopulse radar system of the present invention is provided with a calibration signal transmission line for supplying part of a transmit signal to each of respective receiving antennas or each of signal transmission lines (i.e., each of individual output parts of a plurality of receiving antennas) connected to the receiving antennas as a signal for calibration. The monopulse radar system is also provided with correcting means for calculating an azimuth angle of a pseudo target based on the calibration signal, determining an azimuth angle to be originally calculated by a monopulse radar, using the azimuth angle of the pseudo target, and adjusting at least either amplitude or phase so that the azimuth angle to be originally calculated and the azimuth angle of the pseudo target calculated precedently by each calibration signal coincide with each other. In a preferred embodiment of the present invention, the signals for calibration respectively applied to the output parts of the plurality of receiving antennas are set as being equipower and equiphase. Particularly when directivities of the two receiving antennas are made symmetrically with respect to a central direction, such a state that the signals are inputted to the respective antennas at equal power and in equiphase fashion in this way, occurs when a target is placed on a center line indicative of the center of an angle to be detected by a radar. Thus, a correcting process is performed in such a manner that the azimuth angle of the pseudo target, which is calculated from the signals for-calibration, extends on the center line of the radar. The signal for calibration is used where the signal is always supplied to the output parts of the plurality of receiving antennas, and where a switch is provided on a calibration signal transmission line for supplying the signal calibration and a switch driving unit for controlling conducting and cut-off states of the switch is provided. As the control on the conducting and cut-off states, there are one for normally bringing the calibration signal transmission line to the cut-off state and bringing it to the conducting state upon calibration, and one for generating the conducting state of the switch periodically or with predetermined timing. In particular, a signal processing device such as a DSP is used to perform either one of the above-described calibrations automatically or with arbitrary timing, thereby correcting variations in characteristic developed after product shipment due to environmental variations, time variations in parts characteristic, etc. In the present embodiment, the accuracy of the angle detected by the monopulse radar can be maintained by ever-execution of the calibration. The correcting means of the monopulse radar according to the present invention comprises signal processing means for calculating an azimuth angle of a pseudo target, based on the signal for calibration, determining an azimuth angle to be originally calculated by the monopulse radar through the use of the azimuth angle of the pseudo target, determining correction data so that the azimuth angle to be originally calculated and the azimuth angle of the pseudo target, which is precedently detected by the signal for calibration, coincide with each other, writing the correction data into memory means, and correcting an azimuth angle of a target detected when actually activated as a radar, according to signal processing on the basis of the correction data stored in the memory means. As another preferred embodiment, the signal for calibration is modulated with a low frequency signal. Thus, the calibration signal is superimposed on a reflected signal, thus causing inconvenience. Namely, if the operation of an antenna is not perfectly stopped upon calibration, then a signal radiated from a transmitting antenna is reflected by an object present ahead of the antenna, which is then received by its corresponding receiving antenna depending on environments under which calibration is made. The present embodiment prevents such inconvenience that when a transmit signal is used as a signal for calibration as it is, this signal is superimposed on the calibration signal, so that accurate calibration cannot be performed. The present embodiment is also effective in preventing a low frequency signal converted by a mixer from being brought into a DC current in a homodyne type radar wherein the same ones are used for a local signal generator for generating a transmit signal and a signal generator for generating a local signal supplied to the mixer. BRIEF DESCRIPTION OF SEVERAL VIEWS OF DRAWING FIG. 1 is a block diagram showing a configuration of a first embodiment of a monopulse radar system according to the present invention; FIG. 2 is a block diagram illustrating a configuration of a conventional monopulse radar system; FIG. 3 is a diagram for describing the principle of a phase monopulse radar; FIG. 4 is a characteristic diagram illustrating signals received by amplitude monopulse antennas; FIG. 5 is a gain characteristic diagram showing a sum signal and a differential signal received by the amplitude monopulse antennas; FIG. 6 is a characteristic diagram illustrating a ratio between the sum signal and the differential signal received by the amplitude monopulse antennas; FIG. 7 is a signal strength characteristic diagram of receive signals where an error arises between channels for the amplitude monopulse antennas; FIG. 8 is a gain characteristic diagram showing a sum signal and a differential signal where the error arises between the channels for the amplitude monopulse antennas; FIG. 9 is a characteristic diagram illustrating a ratio between a sum signal and a differential signal where the error occurs between the channels for the amplitude monopulse antennas; FIG. 10 is a block diagram showing a configuration of another embodiment of a monopulse radar system according to the present invention; FIG. 11 is a side cross-sectional view of one embodiment of an in-vehicle radar module which constitutes a monopulse radar system according to the present invention; FIG. 12 is a plan view of an RF circuit shown in FIG. 11; FIG. 13 is a plan view of an antenna section of another embodiment of the in-vehicle radar module which constitutes the monopulse radar system according to the present invention; FIG. 14 is a plan view of an antenna section of a further embodiment of the in-vehicle radar module which constitutes the monopulse radar system according to the present invention; FIG. 15 is a circuit diagram showing a configuration example of a switch used in a monopulse radar system according to the present invention; and FIG. 16 is a circuit diagram illustrating another configuration example of a switch used in a monopulse radar system according to the present invention. DETAILED DESCRIPTION OF THE INVENTION Preferred embodiments of the present invention will hereinafter be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of a first embodiment of a monopulse radar system according to the present invention. The present embodiment is a monopulse radar system which has a transmitting antenna ANT1, and two receiving antennas ANT2 and ANT3 and which radiates or emits a transmit signal from the transmitting antenna ANT1, receives a signal obtained by allowing the transmit signal to be reflected by a target, with the receiving antennas ANT2 and ANT3, and detects an azimuth angle of its target according to signal processing. The monopulse radar system includes a signal transmission line L1 for calibration connected from an oscillator OSC1 to the transmitting antenna ANT1, from which part of the transmit signal is supplied to each of signal transmission lines L2 and L3 connected to the receiving antennas ANT2 and ANT3 as a signal for calibration, and a switch SW1 for bringing the signal transmission line L1 into conduction or a cut off state. Further, a channel CH1 for processing the signal received by one antenna ANT2 is provided with phase correcting means PS1 and amplitude correcting means VGA1. The switch SW1 is brought to a conducting state and at least one of the phase correcting means PS1 comprised of a variable phase shifter and the amplitude correcting means VAG1 comprised of a variable gain amplifier is adjusted so that an azimuth angle of a pseudo target, which is detected according to the signal for calibration, reaches a predetermined angle of a monopulse radar to thereby carry out an angle correction. Described more specifically, when the switch SW1 is brought into conduction, some of the transmit signal are supplied to the two receiving channels CH1 and CH2 via the signal transmission line L1 at equal power and in equiphase fashion. At this time, the switch SW1 is switched or changed over by a low frequency signal source OSC5 so that the signal for calibration is modulated with a low frequency. This signal is amplified by low noise amplifiers LNAL and LNA2 for the respective channels CH1 and CH2. Thereafter, the amplified signals are mixed with a signal produced from an oscillator OSC6 by mixers MIX3 and MIX4 respectively, so that they are converted into signals each having an intermediate frequency. The signal having the intermediate frequency is allowed to pass through the variable phase shifter PS1 and the variable gain amplifier VGA1 in one channel CH1 and then mixed with a signal oscillated from an oscillator OSC7 by use of a mixer MIX5, where it is converted into a low frequency signal. In the other channel CH2, the signal outputted from the mixer MIX4 is directly inputted to a mixer MIX6, where it is converged into a low frequency signal in a manner similar to above. These signals are processed by signal processing means P1. Directivities of the receiving antennas ANT2 and ANT3 are respectively formed symmetrically about the center line corresponding to an angle 0° as in the case of the characteristic curves S1 and S2 shown in FIG. 4. When the respective channels CH1 and CH2 are not coincident in characteristic with each other immediately after the start of calibration processing, the strengths of the low frequency signals outputted from the mixers MIX5 and MIX6 do not coincide with each other even if the input signals are equal in strength and phase. This is represented as shown in a characteristic diagram of FIG. 7 by way of example. Namely, when a signal strength S3 of the one channel CH1 is greater than a signal strength S4 of the other channel CH2 as illustrated in the characteristic diagram of FIG. 7, a signal corresponding to the sum of the two signals and a signal corresponding to the difference between the two signals are represented as a characteristic diagram shown in FIG. 8. Further, the ratio between the sum signal and the differential signal is represented as a characteristic R2 shown in FIG. 9. Since the monopulse radar calculates an angle with a ratio R1 at the time that the characteristics of both channels are equal, as the base, it consequently outputs an angle θ1 other than 0° as the azimuth angle of the pseudo object detected by the signal for calibration. In order to allow the angle θ1 to reach 0°, control signal generating means CNT1 generates a control signal so that the gain of the variable gain amplifier VGA1 is lowered. Finally, the strengths of the low frequency signals outputted from both channels become equal to each other and thereby result in the same form as FIG. 4. According to the present embodiment, since the angle correction of the monopulse radar system is automatically performed on a circuitry basis without human hands, the cost necessary for calibration work. FIG. 10 is a block diagram showing a configuration of another embodiment of a monopulse radar system according to the present invention. The present embodiment is an embodiment used in a vehicle radar using signals lying in a 77 GHz band. Receive characteristics of receiving antennas ANT2 and ANT3 respectively have the receive patterns S1 and S2 symmetric about the center line as shown in FIG. 4. A common signal generator OSC1 is used for a signal generator for generating a transmit signal and signal generators for generating local signals inputted to mixers MIX1 and MIX2. In the present embodiment, a signal for calibration supplied to both channels CH1 and CH2 on the receiving side via a signal transmission line L1 for calibration, passes through each of low noise amplifiers LNA1 and LNA2, after which they are converted into low frequency signals by mixers MIX1 and MIX2. The low frequency signals are signal-analyzed by signal processing means P1, so that a pseudo target based on the signal for calibration is detected. Correction data is determined so that an azimuth angle to the pseudo target at this time reaches 0°, which in turn is stored in memory means MEM1. When the monopulse radar system is normally operated as a vehicle-to-vehicle distance warning system, a switch SW1 is in a cutoff state, and the azimuth of a forward traveling vehicle, which is detected at this time, is corrected based on the correction data stored in the memory means MEM1. FIG. 11 is a side cross-sectional view of one embodiment of an in-vehicle radar module which constitutes a monopulse radar system according to the present invention. The in-vehicle radar module includes an RF circuit RFC and a plane antenna ANT provided on the observe and reverse sides of a base plate B1. Both of the RF circuit RFC and the plane antenna ANT are connected to each other by coaxial transmission lines COX1 and COX2. The RF circuit RFC is covered with a cover COV1 to keep hermeticity. The RF circuit RFC takes such a configuration as shown in a plan view of FIG. 12. An MMIC (Monolithic Microwave Integrated Circuit) comprising a signal oscillator OSC1, mixers MIX1 and MIX2, low noise amplifiers LAN1 and LNA2, a switch SW1, etc. is packaged or mounted on a high-frequency substrate SUB1. Although not illustrated in the drawing, a low frequency signal for switching the switch with a low frequency is supplied from a low frequency signal generator provided outside the module. According to the present embodiment, since corrections are performed according to digital signal processing, the present module is suitable for automatically carrying out these by a signal processing device such as a microcomputer. Signal calibration may be carried out with specific timing when, for example, the power for the radar module is turned on. Further, the corrections can be automatically performed even after shipment of a product. Thus, a vehicle radar corresponding even to environmental variations, time variations in parts characteristic, etc. can be fabricated. FIG. 13 is a plan view of one embodiment of part formed with the antennas referred to above. The present embodiment is an embodiment wherein a signal transmission line L1 for calibration is provided on the same substrate B1 as plane patch antennas for forming one transmitting antenna ANT1 and two receiving antenna ANT2 and ANT3 without being provided on the RF circuit side. According to the present embodiment, calibration having taken into consideration even the influence of signal transmission lines COX1 and COX2 for connecting the surface of each antenna and the RF circuit can be performed and higher-accuracy calibration can be carried out. FIG. 14 is a plan view showing another embodiment of the part formed with the antennas. The present embodiment is a monopulse radar having four receiving antennas. In the present embodiment, transmitting/receiving antennas are made up of plane patch antennas. A transmitting antenna ANT1, four receiving antennas ANT4, ANT5, ANT6 and ANT7 arranged in parallel, and a signal transmission line L1 for calibration are respectively supplied with a calibration signal intended for the four receiving antennas ANT4, ANT5, ANT6 and ANT7 via a switch SW1 in equiphase form and at equal power. Even if the number of channels increases where the present embodiment is used, an angular correction can be made by means similar to the above, and an effect similar to the case where the two channels are used, can be obtained. FIG. 15 is a circuit diagram showing one embodiment of the switch SW1. The switch SW1 is an MMIC formed according to a process similar to other MMIC. A switching diode D is electrically series-connected between an input IN and an output OUT via DC cut capacitances CAP1 and CAP2. Both ends of the switching diode D are supplied with a bias through transmission lines L4 and L5 and a DC cut capacitance CAP3. A control signal terminal CNT2 is provided between the transmission line L4 and the DC cut capacitance CAP3. Each of the DC cut capacitances CAP1, CAP2 and CAP3 has a large capacitance value assumed to be short-circuited for 77 GHz. The bias supply transmission lines L4 and L5 are transmission lines whose leading ends are short-circuited, and respectively have lengths each equal to one-fourth a signal wave length of 77 GHz. Thus, such a bias circuit serves as high impedance in 77 GHz and has no effect on the signal of 77 GHz. A signal for bringing the switch into conduction/cut-off is supplied from the control signal terminal CNT2. Although the diode D is used for the switching device in the present example, a transistor TR such as an FET may be used as shown in FIG. 16. In this case, a control signal terminal CNT2 serves as the gate of the FET. According to the present invention as described above, the angle correction of the monopulse radar can be easily carried out and its correction can also be automatically performed. The present monopulse radar can therefore cope even with variations in characteristic after product shipment due to environmental variations and time variations in parts characteristic. Further, the accuracy of an angle detected by a monopulse radar system can be maintained. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a monopulse radar system, and more specifically to a monopulse radar system for radiating a signal from a transmitting antenna, and receiving a signal reflected by a target with a plurality of receiving antennas to thereby detect an angle of an existing position of the target. 2. Description of the Related Art In a radar system, a monopulse system is known as one method of detecting an azimuth angle to a target. The monopulse system radiates a signal from a transmitting antenna and receives a signal reflected by a target through the use of two or more receiving antennas. At this time, information about the angle of the target to the radar system is obtained from the difference in amplitude or phase between the signals received by the individual antennas. In general, one using the phase difference is called a “phase monopulse”, whereas one using the amplitude difference is called an “amplitude monopulse”. As this type of monopulse radar system, a radar system using a phase monopulse has been described in, for example, Japanese Patent Laid-Open No. H11(1999)-271433. The principle of operation of a monopulse radar system will be explained below using FIG. 2 . A signal generated from a signal generator OSC 1 is radiated or emitted from a transmitting antenna ANT 1 . The radiated signal is reflected by a target, which in turn is received by two receiving antennas ANT 2 and ANT 3 . The received signals are converted into low frequency signals by mixers MIX 1 and MIX 2 , followed by being subjected to signal analytic processing such as FFT (Fast Fourier Transform) in signal processing means P 1 . In the case of the phase monopulse, the difference in phase between signals received by two antennas is determined. When the two receiving antennas are laid out with an interval d defined therebetween as shown in FIG. 3 , the following equation (1) is established between the difference in phase between signals received by them, and an azimuth angle to a target: in-line-formulae description="In-line Formulae" end="lead"? Δφ=(2π d/λ )sin θ (1) in-line-formulae description="In-line Formulae" end="tail"? On the other hand, when the amplitude monopulse is used, directivity S 1 of the receiving antenna ANT 2 and directivity S 2 of the receiving antenna ANT 3 are distributed as represented in a gain characteristic of FIG. 4 . A signal strength based on the sum of the signals received by the two antennas and a signal strength based on the difference between the signals are respectively represented as gain characteristics shown in FIG. 5 . Further determining the ratio between the two from the sum signal and the difference signal results in a gain characteristic R 1 of FIG. 6 . The magnitude of this ratio and angles are associated with each other to thereby determine each corresponding angle. An in-vehicle radar system often makes use of an ultra-high frequency like a millimeter wave. Frequencies ranging from 76 GHz to 77 GHz are assigned to a vehicle radar used in a vehicle-to-vehicle distance warning system for a vehicle. In general, parts used in such an ultra-high frequency are expensive and large in part-to-parts characteristic variations as compared with parts used in a low frequency. Further, since the wave length is very short in the ultra-high frequency like the millimeter wave, variations in characteristic occur even upon assembly of modules for the radar system. On the other hand, the conventional monopulse radar system shown in FIG. 2 detects a phase difference or an amplitude difference from the low-frequency signals produced by the mixers MIX 1 and MIX 2 and calculates the azimuth angle of the target, based on it. Thus, it is necessary to grasp whether a channel CH 1 based on the receiving antenna ANT 2 and a channel CH 2 based on the receiving antenna ANT 3 coincide in characteristic with each other with very high accuracy, or the difference therebetween in advance. In the radar system using signals lying in a millimeter wave band, however, a phase error or an amplitude error is developed between channels due to the aforementioned reason, and an error is developed in a detected azimuth angle of target. As a countermeasure taken against it, a method of detecting and selecting used parts in advance and using only ones matched in characteristic with each other might be adopted. However, this will result in an increase in part cost. Further, variations developed upon part assembly cannot be eliminated. As another countermeasure, there is known a method of actually radiating a radio wave from the forward of a radar system and correcting a phase difference or an amplitude error developed between channels, based on a detected signal obtained therefrom as has been described in, for example, Japanese Patent Laid-Open No. H5(1993)-232215. In such a method, however, the system becomes large-scale and takes a lot of trouble over its calibration work. Therefore, the manufacturing cost thereof will increase due to the new addition of this work. A problem arises in that any countermeasures referred to above do not take into consideration variations in characteristic after the shipment of each product, and the accuracy of a detected angle is deteriorated where variations in characteristic occur due to some kind of factors such as environmental variations, time variations in parts characteristic. Accordingly, it is a main object of the present invention to provide a monopulse radar system capable of easily correcting a phase error or an amplitude error developed between receiving channels corresponding to a plurality of receiving antennas of the monopulse radar system and reducing a manufacturing cost thereof. It is another object of the present invention to provide a monopulse radar system capable of coping even with characteristic variations after product shipment such as environmental variations, time variations in parts characteristic and correcting a phase error and an amplitude error. | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>In order to achieve the above object, a monopulse radar system of the present invention is provided with a calibration signal transmission line for supplying part of a transmit signal to each of respective receiving antennas or each of signal transmission lines (i.e., each of individual output parts of a plurality of receiving antennas) connected to the receiving antennas as a signal for calibration. The monopulse radar system is also provided with correcting means for calculating an azimuth angle of a pseudo target based on the calibration signal, determining an azimuth angle to be originally calculated by a monopulse radar, using the azimuth angle of the pseudo target, and adjusting at least either amplitude or phase so that the azimuth angle to be originally calculated and the azimuth angle of the pseudo target calculated precedently by each calibration signal coincide with each other. In a preferred embodiment of the present invention, the signals for calibration respectively applied to the output parts of the plurality of receiving antennas are set as being equipower and equiphase. Particularly when directivities of the two receiving antennas are made symmetrically with respect to a central direction, such a state that the signals are inputted to the respective antennas at equal power and in equiphase fashion in this way, occurs when a target is placed on a center line indicative of the center of an angle to be detected by a radar. Thus, a correcting process is performed in such a manner that the azimuth angle of the pseudo target, which is calculated from the signals for-calibration, extends on the center line of the radar. The signal for calibration is used where the signal is always supplied to the output parts of the plurality of receiving antennas, and where a switch is provided on a calibration signal transmission line for supplying the signal calibration and a switch driving unit for controlling conducting and cut-off states of the switch is provided. As the control on the conducting and cut-off states, there are one for normally bringing the calibration signal transmission line to the cut-off state and bringing it to the conducting state upon calibration, and one for generating the conducting state of the switch periodically or with predetermined timing. In particular, a signal processing device such as a DSP is used to perform either one of the above-described calibrations automatically or with arbitrary timing, thereby correcting variations in characteristic developed after product shipment due to environmental variations, time variations in parts characteristic, etc. In the present embodiment, the accuracy of the angle detected by the monopulse radar can be maintained by ever-execution of the calibration. The correcting means of the monopulse radar according to the present invention comprises signal processing means for calculating an azimuth angle of a pseudo target, based on the signal for calibration, determining an azimuth angle to be originally calculated by the monopulse radar through the use of the azimuth angle of the pseudo target, determining correction data so that the azimuth angle to be originally calculated and the azimuth angle of the pseudo target, which is precedently detected by the signal for calibration, coincide with each other, writing the correction data into memory means, and correcting an azimuth angle of a target detected when actually activated as a radar, according to signal processing on the basis of the correction data stored in the memory means. As another preferred embodiment, the signal for calibration is modulated with a low frequency signal. Thus, the calibration signal is superimposed on a reflected signal, thus causing inconvenience. Namely, if the operation of an antenna is not perfectly stopped upon calibration, then a signal radiated from a transmitting antenna is reflected by an object present ahead of the antenna, which is then received by its corresponding receiving antenna depending on environments under which calibration is made. The present embodiment prevents such inconvenience that when a transmit signal is used as a signal for calibration as it is, this signal is superimposed on the calibration signal, so that accurate calibration cannot be performed. The present embodiment is also effective in preventing a low frequency signal converted by a mixer from being brought into a DC current in a homodyne type radar wherein the same ones are used for a local signal generator for generating a transmit signal and a signal generator for generating a local signal supplied to the mixer. | 20040406 | 20070501 | 20050901 | 62509.0 | 0 | GREGORY, BERNARR E | MONOPULSE RADAR SYSTEM | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,818,007 | ACCEPTED | Computer method and system for reading and analyzing ECG signals | Computer method and apparatus for reading and analyzing ECG signals includes applying a plurality of heart condition detectors to a subject ECG signal. Each detector produces a respective indication of likelihood of certain heart conditions existing in the subject. A lattice having annotations of the different detector heart conditions is formed from the detector indications. The lattice enables medical personnel to navigate through and hence more easily read the ECG signal data. The lattice effectively provides an indexed or annotated version of the subject ECG signal. | 1. A method of reading and analyzing ECG signals comprising the computer implemented steps of: receiving a subject ECG signal of a subject; applying a plurality of heart condition detectors to the subject ECG signal and therefrom producing indications of likelihood of certain heart conditions existing in the subject; and forming a lattice having annotations from the produced indications, the lattice enabling one to navigate through the subject ECG signal. 2. A method as claimed in claim 1 further comprising the step of traversing the lattice in a manner that shows most likely heart conditions detected in the subject ECG signal. 3. A method as claimed in claim 2 wherein the step of traversing employs a Viterbi algorithm. 4. A method as claimed in claim 1 further comprising the step of determining a path through the lattice based on user-specified criteria. 5. A method as claimed in claim 4 wherein the user-specified criteria includes any combination of type of heart condition, likelihood threshold of a certain heart condition, time length of ECG signal indicating a certain heart condition, sequence of heart conditions and similarity between ECG signals indicating heart conditions. 6. A method as claimed in claim 1 further comprising: providing a database of predetermined lattices having respective associated heart conditions; and comparing the formed lattice against those in the database to determine heart conditions of the subject. 7. A method as claimed in claim 1 further comprising the step of highlighting one or more paths through the lattice such that a focused and/or filtered view of the subject ECG symbol to the user is enabled. 8. Computer apparatus for reading and analyzing ECG symbols comprising: an input member for receiving a subject ECG signal of a subject; a plurality of heart condition detectors; and a scoring module coupled between the input member and the plurality of detectors for applying each detector to the subject ECG signal and therefrom producing indications of likelihood of certain heart conditions existing in the subject; wherein the scoring module forms a lattice from the produced indicators, the lattice enabling one to navigate through the subject ECG signal. 9. Computer apparatus as claimed in claim 8 wherein the formed lattice provides an indexed or annotated view of the subject ECG signal. 10. Computer apparatus as claimed in claim 8 further comprising a process and display engine that enables traversing of the lattice in a manner that shows most likely heart conditions detected in the subject ECG signal. 11. Computer apparatus as claimed in claim 10 wherein the process and display engine employs a Viterbi algorithm to traverse the lattice. 12. Computer apparatus as claimed in claim 8 further comprising a process and display engine that determines a path through the lattice based on user-specified criteria. 13. Computer apparatus as claimed in claim 12 wherein the user-specified criteria includes any combination of type of heart condition, likelihood threshold of a certain heart condition, time length of ECG signal indicating a certain heart condition, sequence of heart conditions and similarity between ECG signals indicating heart conditions. 14. Computer apparatus as claimed in claim 8 further comprising: a database storing predefined lattices having respective determined heart conditions; and a query engine for comparing the formed lattice against the predefined lattices stored in the database to determine heart conditions of the subject. 15. Computer apparatus as claimed in claim 8 further comprising a process and display engine that highlights one or more paths through the lattice such that a focused and/or filtered view of the subject ECG signal to the user is enabled. 16. A computer system for reading and analyzing ECG signals comprising: means for applying a plurality of heart condition detectors to a subject ECG signal of a subject and therefrom producing indications of likelihood of certain heart conditions existing in the subject; and lattice means forming a lattice having annotations from the produced indications, the lattice enabling one to navigate through the subject ECG signal. 17. A computer system as claimed in claim 16 wherein the lattice means includes means for traversing the lattice in a manner that shows most likely heart conditions detected in the subject ECG signal. 18. A computer system as claimed in claim 16 further comprising means for determining a path through the lattice based on user-specified criteria. 19. A computer system as claimed in claim 18 wherein the user-specified criteria includes any combination of type of heart condition, likelihood threshold of a certain heart condition, time length of ECG signal indicating a certain heart condition, sequence of heart conditions and similarity between ECG signals indicating heart conditions. 20. A computer system as claimed in claim 16 further comprising means for highlighting one or more paths through the lattice. | BACKGROUND OF THE INVENTION The electrocardiogram (ECG or sometimes EKG) is a valuable diagnostic tool used extensively by cardiologists worldwide. The ECG records the electrical activity of the heart detected through small electrodes (leads) placed on the patient's chest, wrists and ankles. An examination in a doctor's office might typically collect readings from twelve electrodes and would normally last only up to half an hour. An alternative is for doctors to issue to patients a monitoring device that they take home and wear for a day or two. In this case, typically data from only one or two leads is collected. The data from the ECG leads is normally recorded on paper or stored in the monitoring device's memory. In the case of the examination in the doctor's office, a physician or nurse scans the printouts by hand since there is relatively little data. For the home monitoring case, again scanning is mostly performed by hand. This may be feasible for 24 hours worth of data. However, many heart conditions are transient and infrequent, occurring only once a week or even less often. For these cases, days or weeks of monitoring may be required, generating a large amount of data that must be scanned, either by machine or by a trained professional, in order to reveal abnormal conditions. Thus, most modern ECG machines still rely on a doctor or technician printing out the signal readings and looking through it by hand. This is not only time consuming but could result in important symptoms being overlooked. Furthermore, some ECG machines provide limited analysis of the signal, e.g., heart rate, fibrillation detection and the like. SUMMARY OF THE INVENTION Doctors typically want or need to only look at “interesting” sections of the ECG signals. The present invention alleviates the need for a professional to scan all of the data by hand, allowing fast navigation through the ECG signal. Further, the present invention makes very long term ECG data collection and review feasible in contrast to current techniques in which it is impractical to scan by hand all of the generated data. In turn, this enables detection of heart conditions with very infrequent symptoms but which are nonetheless serious. In one embodiment, the present invention method of reading and analyzing ECG signals includes the computer implemented steps of: (a) receiving a subject ECG signal of a subject; (b) applying a plurality of heart condition detectors to the subject ECG signal and therefrom producing indications of the likelihood of certain heart conditions existing in the subject; and (c) forming a lattice having annotations from the produced indications, the lattice enabling one to navigate through the subject ECG signal. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. FIG. 1 is a schematic diagram of the present invention lattice construction. FIG. 2 is a schematic diagram of querying by example that applies the lattice construction of FIG. 1. FIGS. 3a and 3b are schematic and block diagrams of a computer system employing the present invention. DETAILED DESCRIPTION OF THE INVENTION The present invention alleviates the need for a professional to scan all of the data by hand, allowing fast navigation through a subject ECG signal. By way of overview, the present invention converts the subject ECG signal from voltages over time to an alphabet of symbols. Each symbol corresponds to a known heart pattern. In order to automatically convert the ECG signal to a symbolic representation, the many algorithms published in the ECG literature are used. For example, to detect myocardial ischemia, a condition in which heart muscles do not receive enough oxygen, the algorithm in “Automatic Detection of ST-T Complex Changes on the ECG Using Filtered RMS Difference Series: Application to Ambulatory Ischemia Monitoring,” J. Garcia, S. Olmos and P. Laguna, IEEE Transactions on Biomedical Engineering, Vol. 47, No. 9, September 2000, can be applied to the ECG signal. In the present invention, detectors are implemented for as many heart conditions as desired. Currently, over 80 syndromes can be detected from ECG's by cardiologists (see “ABC of Clinical Electrocardiography” by Francis Morrus, BMJ Publishing Group, 01-2003, ISBN 0727915363 and “ECGs by Example”, by Jenkings and Gerred, 1997, IBSN 0443056978). For a number of these conditions, algorithms (detectors) have been published which automatically analyze the ECG and return either a binary “yes/no” decision as to whether the condition is present at time t or a confidence score describing how confident the algorithm is of detecting that signal. The aim of the present invention is not to detect abnormal heart conditions but to facilitate professionals' discovery of them in vast quantities of data. To this end, the present invention constructs a lattice over the ECG signal and uses the lattice to aid navigation through the data. A lattice is a directed graph (left to right) showing many possible alternative paths through the maze of hypotheses. The lattice consists of nodes, which correspond to points in time, and arcs, which correspond to transitions between nodes. The invention process 11 of constructing a lattice from an ECG signal is shown in FIG. 1. The steps are as follows. First, the subject ECG signal 15 is segmented into chunks 27 (data segments) by windowing step 100. The length of each chunk 27 is arbitrary but should be sufficiently long such that the detection algorithms can make a decision for that chunk. Feature extraction step 102 assists in determining boundaries of chunks 27 (i.e., chunk length). Example techniques for feature extraction include: detecting change in signal pattern, detecting change in overall signal amplitude and detecting change in frequency of 0-line crossings. See “ABC of Clinical Electro Cardiography” by Francis Morrus cited above. Chunks 27 can also potentially overlap in time. A typical chunk length might be fifteen minutes worth of data. The various heart condition detectors 12 (mentioned previously) or other classifiers are then applied to each chunk at step 110. Preferably each classifier/detector 12 is directed at detecting a respective specific heart condition given an input ECG signal. Each classifier/detector 12 on output provides a number (for example, simply 1 or 0) or score describing the likelihood of that particular heart condition being present in the chunk 27. Each detector 12 may also generate a confidence level or error rate of its score result. Using the numerical results (scores) of the detectors 12, an N×M lattice 112 is constructed where N is the number of chunks 27 and M is the number of heart conditions in the alphabet. The alphabet may include the “normal” condition. If more than one detector 12 is implemented for the same heart condition, these can be either included separately in the lattice 112 or their scores combined using voting or another combination technique. It may be necessary to normalize or weight the scores from the different classifiers 12 so they can be compared to each other. The weighting may be empirical or it can reflect prior beliefs about those conditions in the general population or specific to the patient according to his/her medical history. In a preferred embodiment, the lattice 112 initially contains one node per sample (chunk 27) of the subject ECG signal 15 or sequence to be represented. The node is labeled by time (or sequence order). In practice, many nodes can be removed as uninteresting without loss of information. Initial time arcs are created linking each node to its successor in time. The arcs can be explicitly represented or can remain implicit. Additional arcs are created by scoring multiple classifiers or feature detectors 12 against the subject ECG signal 15. These classifiers can be run in series or in parallel. Each classifier 12 decides when a segment 27 of the subject signal 15 matches its internal model. When this happens, an arc is created, spanning the matched segment 27, and labeled with the class or feature (e.g., “atrial fibrillation”, “infarction”, “ischemia”, etc.) that was detected. The label may also indicate level of confidence (P=0.x) of the feature detected as illustrated in FIG. 1. As such, the labels serve as helpful annotations for the medical professional. Each path through the lattice 112 corresponds to an alternative segmentation of the ECG signal 15. A time axis or other indication of time enables correspondence between the lattice 112 and the original ECG signal 15. Next, the generated lattice 112 is processed by process and display engine 114 in a variety of ways to aid ECG analysis. First, a “best path” through the lattice 112 is determined using the Viterbi algorithm. This produces the most likely heart condition, including normal, for each chunk 27. Such could be used, for example, by a physician to show all chunks (segments of subject ECG signal 15) which probably exhibit Condition A. For infrequently occurring conditions, this would allow a professional to quickly “zoom” to (filter and focus on) the sections of the ECG readout 15 which exhibit a particular condition. The output of a Viterbi search over the lattice 112 can also be used to visualize the ECG signal 15. Here, a different color is assigned to each heart condition in the alphabet and a timeline is displayed with each chunk 27 shown in the color of the more likely condition. Again, this allows the professional to zoom to (quickly see/view at a glance) areas showing abnormal heartbeats. The lattice 112 may be processed in yet more ways. For example, digging deeper than simply the best path, the physician can ask a variety of quite complex queries. For example, he could ask to view all the chunks 27 with likelihood (confidence P value) of Condition A greater than x and that of Condition B greater than y. Or to view chunks for which Condition C has likelihood (P value) greater than z for n seconds. Another type of possible search is for a sequence of events. For example, the physician could search for Condition A, followed by Conditions B and C. This is a standard type of search through a lattice 112. It can be performed either by scanning through the lattice for a particular pattern or if it is known that for example three-condition sequences are commonly searched for, then an index of all possible three-condition sequences can be built and utilized. The full lattice 112 may also be used to construct another type of useful visualization of the data. Here, the full grid is displayed as a 2-D plot with the color of each point reflecting whether the number is large or small. For example, large numbers can be assigned red, small numbers blue and intermediate numbers are assigned colors between red and blue in the spectrum (or vice versa). The display is similar to a checkerboard pattern with red and orange sections indicating that a particular condition is present or likely to be present. A physician can again use this visualization to zoom to (focus his attention to) abnormal sections of the initial ECG signals 15. In yet another embodiment, the invention system 11 is used to study correlations between ECG's 15 collected from more than one patient. Either the Viterbi best path or the full lattice 112 can be used. To accomplish the foregoing, process and display engine 114 employs known techniques for selecting paths based on user specified criteria and for sorting, color coding, highlighting display of, filtering, zooming, etc. paths in part or whole. Also, if a doctor has an ECG recording 15 that he cannot identify, he may search for this in the lattices of pre-recorded records. An example of this is shown in FIG. 2. Here the query lattice 112 (formed by the process 11 of FIG. 1 from a patient's ECG 15) is compared with a data store 31 of lattices and the closest matches 33 are returned. These matches may be further filtered by patient age, medical history, weight and the like. The closest match gives an initial or preliminary diagnosis for the subject patient's ECG 15. The data store 31 may be implemented as a database holding previously generated lattices 37 and corresponding ECG's 39 that produced those lattices of various patients. The query engine 35 of the database management system then uses the current patient's (subject) lattice 112 (the “query” lattice) as input. The query engine 35 determines the predefined lattices 37 that most closely match the input subject lattice 112. The heart conditions associated with the closest matching predefined lattices 37 provide an analysis of the subject ECG 15. Further, instead of generating a lattice 112, each ECG signal 15 may be converted to a “signature” vector. Each component of the vector is the sum or another combination of the classifier 12 outputs for each chunk 27. Thus time information is thrown away but the ECG signal 15 is represented in a simple form (the signature vector). This would not allow zooming to important parts of the original ECG signal 15 but would however facilitate fast comparison between patient ECG's and would speed diagnosis. Also, some patients with a history of heart conditions may have permanently abnormal ECG's (due to permanent tissue damage). For these patients, it may be desirable to discover only those portions of the ECG signal 15 which are significantly different from the usual abnormal state. In this case, invention apparatus 11 allows the professionals either to modify the thresholds and settings of the classifiers 12 or to completely ignore the output from some classifiers 12. Finally, although this disclosure has been written with indexing/visualization aims in mind, it is clear that a program which analyzes the lattice 112 in real time could be used to raise alarms of various syndromes. Illustrated in FIGS. 3a and 3b is a computer system embodying the present invention. ECG apparatus 41 is connected to a patient (subject) 43. Readings (signals) 45 from the ECG apparatus 41 are input (e.g., downloaded or otherwise transmitted) to computer system 47 implementing the present invention. In particular, computer system 47 (i) constructs a lattice 112 (including labels, annotations, etc.) corresponding to subject ECG signals 45 and (ii) provides display processing and querying of the lattice 112 to assist the physician in navigating through and more pointedly (in a focused and/or filtered manner) visualizing the ECG data as described above in FIGS. 1 and 2. As such, computer system 47 serves as a tool for assisting with the reading and analysis of ECG signals/data. As shown in FIG. 3b, each computer system 47 preferably contains system bus 79, where a bus is a set of hardware lines used for data transfer among the components of a computer. Bus 79 is essentially a shared conduit that connects different elements of a computer system (e.g., processor, disk storage, memory, input/output ports, network ports, etc.) that enables the transfer of information between the elements. Attached to system bus 79 is I/O device interface 82 for connecting various input and output devices (e.g., displays, printers, speakers, etc.) to the computer system. Subject ECG signals 45 are received through I/O device interface 82. Network interface 86 allows the computer system to connect to various other devices attached to a network. Memory 90 provides volatile storage for computer software instructions (e.g., Program Routines 92 and Data 94) used to implement an embodiment of the present invention. Program routines 92 include invention process 11, heart detector/classifiers 12 and query engine 35 and database subsystem for example of FIGS. 1 and 2. Data 94 includes the corpora 31 of stored lattices 37 and associated ECG signals 39. Disk storage 95 provides non-volatile storage for computer software instructions and data used to implement an embodiment of the present invention. Central processor unit 84 is also attached to system bus 79 and provides for the execution of computer instructions. Network interface 86 enables invention program (routine) 11 to be downloaded or uploaded across a network (e.g., local area network, wide area network or global network). I/O device interface 82 enables invention process 11 to be ported between computers on diskette or other computer readable medium (CD-ROM, etc.). Other transmission of process 11 in whole or in part between computers is in the purview of one skilled in the art. Accordingly, invention process 11 may be run on a standalone computer, distributed across computer networks, or executed in a client-server fashion or other arrangement. While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. For example, the invention system may be applied to human or other subjects. Also, restated, the present invention provides a method and system for indexing or annotating ECG signals (readings). The labels of the generated lattice 112 provide indications of heart conditions and levels of confidence of detected conditions. The ECG signal together (either overlaid or otherwise correlated) with these labels (the lattice 112) provide the physician-user with an indexed or annotated version of the ECG. | <SOH> BACKGROUND OF THE INVENTION <EOH>The electrocardiogram (ECG or sometimes EKG) is a valuable diagnostic tool used extensively by cardiologists worldwide. The ECG records the electrical activity of the heart detected through small electrodes (leads) placed on the patient's chest, wrists and ankles. An examination in a doctor's office might typically collect readings from twelve electrodes and would normally last only up to half an hour. An alternative is for doctors to issue to patients a monitoring device that they take home and wear for a day or two. In this case, typically data from only one or two leads is collected. The data from the ECG leads is normally recorded on paper or stored in the monitoring device's memory. In the case of the examination in the doctor's office, a physician or nurse scans the printouts by hand since there is relatively little data. For the home monitoring case, again scanning is mostly performed by hand. This may be feasible for 24 hours worth of data. However, many heart conditions are transient and infrequent, occurring only once a week or even less often. For these cases, days or weeks of monitoring may be required, generating a large amount of data that must be scanned, either by machine or by a trained professional, in order to reveal abnormal conditions. Thus, most modern ECG machines still rely on a doctor or technician printing out the signal readings and looking through it by hand. This is not only time consuming but could result in important symptoms being overlooked. Furthermore, some ECG machines provide limited analysis of the signal, e.g., heart rate, fibrillation detection and the like. | <SOH> SUMMARY OF THE INVENTION <EOH>Doctors typically want or need to only look at “interesting” sections of the ECG signals. The present invention alleviates the need for a professional to scan all of the data by hand, allowing fast navigation through the ECG signal. Further, the present invention makes very long term ECG data collection and review feasible in contrast to current techniques in which it is impractical to scan by hand all of the generated data. In turn, this enables detection of heart conditions with very infrequent symptoms but which are nonetheless serious. In one embodiment, the present invention method of reading and analyzing ECG signals includes the computer implemented steps of: (a) receiving a subject ECG signal of a subject; (b) applying a plurality of heart condition detectors to the subject ECG signal and therefrom producing indications of the likelihood of certain heart conditions existing in the subject; and (c) forming a lattice having annotations from the produced indications, the lattice enabling one to navigate through the subject ECG signal. | 20040405 | 20060606 | 20051006 | 62953.0 | 0 | ANTHONY, JESSICA LYNN | COMPUTER METHOD AND SYSTEM FOR READING AND ANALYZING ECG SIGNALS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,818,133 | ACCEPTED | Sram device having high aspect ratio cell boundary | A static random access memory (SRAM) device including a substrate and an SRAM unit cell. The substrate includes an n-doped region interposing first and second p-doped regions. The SRAM unit cell includes: (1) a first pass-gate transistor and a first pull-down transistor located at least partially over the first p-doped region; (2) first and second pull-up transistors located at least partially over the n-doped region; and (3) a second pass-gate transistor, a second pull-down transistor, and first and second read port transistors, all located at least partially over the second p-doped region. A boundary of the SRAM unit cell comprises first and second primary dimensions having an aspect ratio of at least about 3.2. | 1. A static random access memory (SRAM) device, comprising: a substrate having an n-doped region interposing first and second p-doped regions; and an SRAM unit cell including: a first pass-gate transistor and a first pull-down transistor located at least partially over the first p-doped region; first and second pull-up transistors located at least partially over the n-doped region; and a second pass-gate transistor, a second pull-down transistor, and first and second read port transistors, all located at least partially over the second p-doped region; wherein a boundary of the SRAM unit cell comprises first and second primary dimensions having an aspect ratio of at least about 3.5. 2. The SRAM device of claim 1 further comprising: a write port bit line electrically coupled to a source/drain contact of the first pass-gate transistor; a write port bit-bar line electrically coupled to a source/drain contact of the second pass-gate transistor; and a read port bit line electrically coupled to a source/drain contact of at least one of the first and second read port transistors. 3. The SRAM device of claim 2 wherein the write port bit line, the write port bit-bar line, and the read port bit line are each substantially perpendicular to a longitudinal axis of the SRAM unit cell boundary within the SRAM unit cell boundary. 4. The SRAM device of claim 1 further comprising: a write port word line electrically coupled to gate contacts of the first and second pass-gate transistors; and a read port word line electrically coupled to a gate contact of one of the first and second read port transistors. 5. The SRAM device of claim 4 wherein the write port and read port word lines are each substantially parallel to a longitudinal axis of the SRAM unit cell boundary within the SRAM unit cell boundary. 6. A static random access memory (SRAM) device, comprising: a substrate having an n-doped region interposing first and second p-doped regions; and an SRAM unit cell including: a first pull-down transistor and a first pass-gate transistor located at least partially over the first p-doped region; first and second pull-up transistors located at least partially over the n-doped region; and a second pull-down transistor and second, third, and fourth pass-gate transistors all located at least partially over the second p-doped region; wherein a boundary of the SRAM unit cell comprises first and second primary dimensions having an aspect ratio of at least about 3.5. 7. The SRAM device of claim 6 further comprising: a first port bit line electrically coupled to a source/drain contact of the first pass-gate transistor; a first port bit-bar line electrically coupled to a source/drain contact of the second pass-gate transistor; a second port but line electrically coupled to a source/drain contact of the third pass-gate transistor; and a second port but-bar line electrically coupled to a source/drain contact of the fourth pass-gate transistor. 8. The SRAM device of claim 7 wherein the first and second port bit lines and bit-bar lines are each substantially perpendicular to a longitudinal axis of the SRAM unit cell boundary within the SRAM unit cell boundary. 9. The SRAM device of claim 6 further comprising: a first port word line electrically coupled to gate contacts of the first and second pass-gate transistors; and a second port word line electrically coupled to a gate contact of the third and fourth pass-gate transistors. 10. The SRAM device of claim 9 wherein the first and second port word lines are each substantially parallel to a longitudinal axis of the SRAM unit cell boundary within the SRAM unit cell boundary. 11. A static random access memory (SRAM) device, comprising: a substrate having an n-doped region interposing first and second p-doped regions; and an SRAM unit cell including: a first pass-gate transistor and a first pull-down transistor located at least partially over the first p-doped region; first and second pull-up transistors located at least partially over the n-doped region; and a second pass-gate transistor, a second pull-down transistor, and first and second read port transistors, all located at least partially over the second p-doped region; wherein a boundary of the SRAM unit cell comprises first and second primary dimensions having an aspect ratio of at least about 3.2. 12. The SRAM device of claim 11 wherein the aspect ratio ranges between about 3.2 and about 6. 13. The SRAM device of claim 11 wherein the first primary dimension is less than about 0.5 μm, which is less than the second primary dimension. 14. The SRAM device of claim 11 wherein the first primary dimension is less than about 1.8 μm, which is greater than the second primary dimension. 15. The SRAM device of claim 11 further comprising: a first ground conductor electrically coupled to a source/drain contact of the first pull-down transistor and extending in a first direction; and a second ground conductor electrically coupled to a source/drain contact of the second pull-down transistor and extending in a second direction that is substantially perpendicular to the first direction. 16. The SRAM device of claim 11 wherein a maximum resistance between either of the first and second p-doped regions and an active region of one of the transistors located in one of the first and second p-doped regions is less than about 3000 Ω. 17. The SRAM device of claim 11 wherein at least one of the first and second pass-gate and pull-down transistors is an NMOS transistor, wherein a maximum distance between the n-doped region and an active region of the NMOS transistor is less than about 70 nm. 18. A static random access memory (SRAM) device, comprising: a substrate having an n-doped region interposing first and second p-doped regions; and an SRAM unit cell including: a first pass-gate transistor and a first pull-down transistor located at least partially over the first p-doped region; first and second pull-up transistors located at least partially over the n-doped region; a second pass-gate transistor, a second pull-down transistor, and first and second read port transistors, all located at least partially over the second p-doped region; a first transistor active region implanted in the first p-doped region and extending between source/drain contacts of the first pass-gate transistor and the first pull-down transistor; and a second transistor active region implanted in the second p-doped region and extending between source/drain contacts of the second pass-gate transistor and the second pull-down transistor. 19. The SRAM device of claim 18 further comprising a third transistor active region implanted in the second p-doped region and extending between source/drain contacts of the first and second read port transistors. 20. The SRAM device of claim 19 further comprising: a read port word line electrically coupled to a gate contact of the first read port transistor; a read port bit line electrically coupled to a drain contact of the first read port transistor; a gate conductor at least partially forming a gate contact of the second read port transistor and a gate contact of the second pull-down transistor; and a ground conductor electrically coupled to a source contact of the second read port transistor; wherein the third transistor active region couples a source contact of the first read port transistor and a drain contact of the second read port transistor. 21. The SRAM device of claim 18 further comprising a first interconnect structure metal layer comprising a plurality of first metal layer conductors, including a first L-shaped interconnect coupling drain contacts of the first pass-gate transistor and the first pull-up transistor with a gate contact of the second pull-up transistor. 22. The SRAM device of claim 21 wherein the plurality of first metal layer conductors further includes a power source line landing pad, a ground conductor line landing pad, a bit line landing pad, a bit-bar line landing pad, a write word line landing pad, and a read word line landing pad. 23. The SRAM device of claim 21 wherein the plurality of first metal layer conductors includes a second L-shaped interconnect coupling drain contacts of the second pass-gate transistor and the second pull-up transistor with a gate contact of the first pull-up transistor. 24. The SRAM device of claim 21 further comprising a second interconnect structure metal layer comprising a plurality of second metal layer conductors, including a power source line interconnect, a ground line interconnect, a write bit line interconnect, a write bit-bar line interconnect, a read bit line interconnect, and word line landing pads. 25. The SRAM device of claim 24 further comprising a plurality of first vias coupling ones of the plurality of first metal layer conductors with corresponding ones of the second metal layer conductors. 26. The SRAM device of claim 24 further comprising a third interconnect structure metal layer comprising a plurality of third metal layer conductors, including a ground line interconnect, a write word line interconnect, and a read word line landing pad. 27. The SRAM device of claim 26 further comprising a plurality of second vias coupling ones of the plurality of second metal layer conductors with corresponding ones of the third metal layer conductors. 28. The SRAM device of claim 26 further comprising a fourth interconnect structure metal layer comprising a plurality of fourth metal layer conductors, including at least one read word line interconnect. 29. The SRAM device of claim 28 further comprising a plurality of third vias coupling ones of the plurality of third metal layer conductors with corresponding ones of the fourth metal layer conductors. 30. The SRAM device of claim 18 wherein at least one of the transistors includes a gate dielectric layer comprising a material selected from the group consisting of: SiO2; SiON; HfO; Ta2O5; and Al2O3. 31. The SRAM device of claim 18 wherein at least one of the transistors includes a gate dielectric layer comprising a material selected from the group consisting of: nitrided oxide; CVD oxide; and thermal oxide. 32. The SRAM device of claim 18 wherein at least one of the transistors includes a gate dielectric layer comprising a nitrogen containing dielectric material. 33. The SRAM device of claim 18 wherein at least one of the transistors includes a gate dielectric layer comprising a high-k dielectric material. 34. The SRAM device of claim 18 wherein the n-doped region and the first and second p-doped region are enclosed within a deep n-doped region. 35. The SRAM device of claim 18 wherein a maximum capacitance of a write port charge storage node of the SRAM unit cell is less than about 0.6 farads. 36. The SRAM device of claim 18 wherein the area of the SRAM unit cell boundary is less than about 500(WGPD2), wherein WGPD is the width of a gate of one of the first and second pull-down transistors. 37. The SRAM device of claim 18 wherein the substrate comprises a material selected from the group consisting of: bulk Si; SiGe; strained Si; silicon-on-insulator (SOI); silicon-on-nothing (SON); and diamond. 38. The SRAM device of claim 18 wherein the SRAM unit cell further comprises a plurality of ground conductor lines on at least two metal layers of an interconnect structure interconnecting the transistors. 39. The SRAM device of claim 18 wherein the SRAM unit cell further comprises a bit line and a bit-bar line on different metal layers of an interconnect structure interconnecting the transistors. 40. The SRAM device of claim 18 wherein the area of one of the first and second p-doped regions within the SRAM unit cell boundary is greater than the area of the other of the first and second p-doped regions within the SRAM unit cell boundary by an amount ranging between about 100% and about 500%. 41. The SRAM device of claim 18 wherein a boundary of the SRAM unit cell has a length ranging between about 0.32 microns and about 8 microns and a width ranging between about 0.08 microns and about 2 microns. 42. The SRAM device of claim 18 wherein a boundary of the SRAM unit cell has a length ranging between about 12 nm and about 80 nm and a width ranging between about 3 nm and about 20 nm. 43. The SRAM device of claim 18 wherein a boundary of the SRAM unit cell has an aspect ratio ranging between about 3 and about 6. 44. The SRAM device of claim 18 wherein a boundary of the SRAM unit cell has an aspect ratio of about 3.2. 45. The SRAM device of claim 18 wherein a boundary of the SRAM unit cell has an aspect ratio of about 3.5. 46. A method of manufacturing a static random access memory (SRAM) device, comprising: providing a substrate having a first doped region of a first dopant type, the first doped region interposing second and third doped regions of a second dopant type; forming first and second pull-up transistors at least partially over the first doped region; forming a first pass-gate transistor and a first pull-down transistor at least partially over the second doped region; and forming a second pass-gate transistor, a second pull-down transistor, and first and second read port transistors, all at least partially over the third doped region; wherein the first and second pass-gate, pull-down, pull-up, and read port transistors form an SRAM unit cell, a boundary of the SRAM unit cell having first and second primary dimensions forming an aspect ratio of at least about 3.2. 47. The method of claim 46 wherein the first and second pull-up transistors are PMOS transistors and the first and second pass-gate, pull-down, and read port transistors are NMOS transistors. 48. The method of claim 46 further comprising: forming a write port bit line electrically coupled to a source/drain contact of the first pass-gate transistor; forming a write port bit-bar line electrically coupled to a source/drain contact of the second pass-gate transistor; and forming a read port bit line electrically coupled to a source/drain contact of at least one of the first and second read port transistors. 49. The method of claim 48 wherein the write port bit line, the write port bit-bar line, and the read port bit line are each substantially perpendicular to a longitudinal axis of the SRAM unit cell boundary within the SRAM unit cell boundary. 50. The method of claim 46 further comprising: forming a write port word line electrically coupled to gate contacts of the first and second pass-gate transistors; and forming a read port word line electrically coupled to a gate contact of one of the first and second read port transistors. 51. The method of claim 50 wherein the write port and read port word lines are each substantially parallel to a longitudinal axis of the SRAM unit cell boundary within the SRAM unit cell boundary. 52. An integrated circuit device, comprising: a substrate having a plurality of first doped regions of a first dopant type, a plurality of second doped regions of a second dopant type, and a plurality of third doped regions of the second dopant type, each of the first doped regions interposing one of the plurality of second doped regions and one of the plurality of third doped regions; a plurality of static random access memory (SRAM) devices each including: first and second pull-up transistors located at least partially over one of the plurality of first doped regions; a first pass-gate transistor and a first pull-down transistor located at least partially over one of the plurality of second doped regions adjacent the one of the plurality of first doped regions; and a second pass-gate transistor, a second pull-down transistor, and first and second read port transistors, all located at least partially over one of the plurality of third doped regions adjacent the one of the plurality of first doped regions and opposite the one of the plurality of second doped regions; wherein the first and second pass-gate, pull-down, pull-up, and read port transistors form an SRAM unit cell, a boundary of the SRAM unit cell having first and second primary dimensions forming an aspect ratio of at least about 3.2; and a plurality of interconnects interconnecting ones of the first and second pull-up, pass-gate, pull-down, and read port transistors. 53. The integrated circuit device of claim 52 further comprising: a write port bit line electrically coupled to a source/drain contact of each of the first pass-gate transistors; a write port bit-bar line electrically coupled to a source/drain contact of each of the second pass-gate transistors; and a read port bit line electrically coupled to a source/drain contact of ones of the first and second read port transistors. 54. The integrated circuit device of claim 52 further comprising: a write port word line electrically coupled to gate contacts of each of the first and second pass-gate transistors; and a read port word line electrically coupled to a gate contact of ones of the first and second read port transistors. | CROSS-REFERENCE This application is related to the following commonly-assigned U.S. patent application, the entire disclosure of which is hereby incorporated herein by reference: “INTEGRATED CIRCUIT DEVICE WITH CROSSED POWER STRAP LAYOUT,” Ser. No. 60/527,857, filed Dec. 5, 2003, under Attorney Docket No. 24061.153, having Jhon Jhy Liaw named as inventor. BACKGROUND The present disclosure relates generally to static random access memory (SRAM) devices and, more specifically, to an SRAM device having a high aspect ratio cell boundary. The physical dimension of a feature on a chip is referred to as “feature size.” Reducing the feature size on a chip permits more components to be fabricated on each chip, and more components to be fabrication on each silicon wafer, thereby reducing manufacturing costs on a per-wafer and a per-chip basis. Increasing the number of components in each chip can also improve chip performance because more components may become available to satisfy functional requirements. SRAM devices are one type of device that may undergo such scaling to reduce manufacturing costs. SRAM is random access memory that retains data bits in its memory as long as power is being supplied. Unlike dynamic random access memory (DRAM), SRAM does not have to be periodically refreshed. SRAM also provides faster access to data than DRAM. Thus, for example, SRAM is frequently employed in a computer's cache memory, or as part of the random access memory digital-to-analog converters in video cards. However, SRAM is more expensive than other types of memory. Thus, SRAM designers and manufacturers continually strive to reduce the costs of manufacturing SRAM devices. The scaling of features sizes discussed above is one of the means to achieve such cost reduction. However, scaling feature sizes is not the only means available to reduce SRAM manufacturing costs. For example, modifying the layout of features within an SRAM chip to further increase the packing density of SRAM cells within each chip can also reduce manufacturing costs. Accordingly, what is needed in the art is an SRAM device and method of manufacture thereof that addresses the above discussed issues. BRIEF DESCRIPTION OF THE DRAWINGS Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. FIG. 1 illustrates a layout view of one embodiment of an SRAM device in an intermediate stage of manufacture according to aspects of the present disclosure. FIG. 2 illustrates a layout view of the SRAM device shown in FIG. 1 in a subsequent stage of manufacture. FIG. 3 illustrates a layout view of the SRAM device shown in FIG. 2 in a subsequent stage of manufacture. FIG. 4 illustrates a layout view of the SRAM device shown in FIG. 3 in a subsequent stage of manufacture. FIG. 5 illustrates a layout view of the SRAM device shown in FIG. 4 in a subsequent stage of manufacture. FIG. 6 illustrates a circuit diagram of another embodiment of an SRAM device according to aspects of the present disclosure. FIG. 7 illustrates a circuit diagram of another embodiment of the SRAM device shown in FIG. 6. FIG. 8 illustrates a plan view of a portion of an SRAM device manufacturing wafer according to aspects of the present disclosure. DETAILED DESCRIPTION It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. Referring to FIG. 1, illustrated is a layout view of one embodiment of an SRAM device 100 constructed according to aspects of the present disclosure. The SRAM device 100 includes a substrate 105, an n-doped region 110, p-doped regions 115a, 115b, and SRAM unit cells 120a-i. Although only shown for SRAM unit cell 120e, each of the SRAM unit cells 120a-i may include active regions 130a-e and gate electrodes 140a-e within a unit cell boundary 125. In one embodiment, the unit cell boundary 125 indicates an approximate midpoint between perimeter components of neighboring cells 120a-i. For example, in the illustrated embodiment, the upper segment of the cell boundary 125 (relative to the figure) may be located about midway between the outermost edge of the gate electrode 140c of cell 120e and the outermost edge of the gate electrode 140b of cell 120d. The area enclosed by the unit cell boundary 125 may also be proportional to one of the features in each unit cell 120a-i. For example, the area may be less than about 500(WGDP2), wherein WGDP is the width of the gate electrode 140b, 140c, or other features. The substrate 105 may comprise silicon, gallium arsenide, gallium nitride, strained silicon, silicon germanium, silicon carbide, carbide, diamond, and/or other materials. The substrate 105 may also be or comprise a silicon-on-insulator (SOI) substrate, such as a silicon-on-sapphire substrate, a silicon germanium-on-insulator substrate, or another substrate comprising an epitaxial semiconductor layer on an insulator layer. In one embodiment, the substrate 105 may include an air gap to provide insulation of microelectronic devices formed thereon. For example, a silicon-on-nothing (SON) structure may be employed, such that the substrate 105 may include a thin insulation layer or gap comprising air and/or another insulator. In one such embodiment, the substrate 105 includes a silicon cap layer over or on a silicon germanium layer, wherein the silicon germanium layer is substantially or partially removed to form an air gap or void, thereby leaving the silicon cap layer as an insulated device active region for subsequently formed microelectronic devices. The n-doped region 110 may be formed by a high energy implant through a patterned photoresist layer and into the substrate 105. N-type dopant impurities employed to form the n-doped region 110 may comprise phosphorus, arsenic, P31, stibium, and/or other materials. Subsequent diffusion, annealing, and/or electrical activation processes may also be employed after the impurity is implanted. The p-doped regions 115a, 115b may be similarly formed, although possibly with an energy level decreased, for example, in proportion to the atomic masses of the n-type and p-type dopants. P-type dopant impurities may comprise boron, boron fluoride, indium, and/or other materials. As with the formation of the n-doped region 110, formation of the p-doped regions 115a, 115b may include one or more diffusion, annealing, and/or electrical activation processes. Moreover, doping schemes other than that shown in the exemplary embodiment of FIG. 1 may be employed within the scope of the present disclosure. For example, the n-doped region 110 may be or comprise a p-doped well and the p-doped regions 115a, 115b may each be or comprise an n-doped well. Similarly, the doped regions 110, 115a, 115b may be doped with similar dopant types, although to varying degree of impurity concentration. Although not illustrated, the doped regions 110, 115a, 115b may collectively be enclosed in a deep n-doped or p-doped well. In one embodiment, the doped regions 110, 115a, 115b employ boron as a p-type dopant and deuterium-boron complexes as an n-type dopant. The deuterium-boron complexes may be formed by plasma treatment of boron-doped diamond layers with a deuterium plasma. Alternatively, deuterium may be replaced with tritium, hydrogen, and/or other hydrogen-containing gases. The impurity concentration of the doped regions may be controlled by a direct current or a radio frequency bias of the substrate 105. The above-described processes may also be employed to form lightly-doped source/drain regions and/or at least portions of the active regions 130a-e in the substrate 105. The active regions 130a-e may be subdivided or designated portions of the doped regions 110, 115a, 115b, or regions of different impurity concentration compared to the doped region in which a particular one of the active regions 130a-e is located. However, in one embodiment, the active regions 130a-e may be formed by first defining an oxide region over, on, or from the substrate 105. The oxide region may be defined by and/or during the same steps performed to define gate oxide layers corresponding to the gate electrodes 140a-e. A polysilicon layer may then be formed over the oxide region, possibly by selective deposition or by blanket deposition followed by patterning. In such an embodiment, the polysilicon layer may be a portion of the gate electrodes 140a-e. However, in some embodiments the polysilicon layer may not be formed. The polysilicon layer may also undergo a silicide process to form a silicide layer thereon. For example, the silicide may comprise TiSi2, CoSi2, NiSi2, WSi2 and/or other materials that may be suitable for a silicided gate interconnect. While not all embodiments will include the silicide layer, when the silicided layer is employed it may form a portion of the gate electrodes 140a-e. The active regions 130a-e may also undergo an ion implantation process, perhaps at an energy ranging between about 30 keV and about 400 keV with an impurity concentration ranging between about 1×1015 atoms/cm2 and about 1×1017 atoms/cm2. The ion implant process may implant ions such that a higher concentration is located within the active regions 130a-e relative to neighboring components, features, or regions. The ion implant process may also implant ions in regions of the substrate 105 underlying the oxide regions, polysilicon layers, and/or silicide layers discussed above, when employed, thereby forming the active regions 130a-130e at least partially in the substrate 105. However, in one embodiment, the active regions 130a-e may be formed entirely within, on, or over the substrate 105. When the polysilicon layers and/or silicide layers described above are employed, the ion implant process utilized to form the active regions 130a-e may be performed before or after the above-described polysilicon layers and/or the silicide layers are formed. Additional and/or alternative processes may also be employed to form the active regions 130a-e. Moreover, in one embodiment, the resistance of the active regions 130a-e may range between about 1 kΩ and about 100 kΩ. For example, the resistance of the active regions 130a-e, or the resistance of the interfaces between the resistance of the active regions 130a-e and adjacent components, features, or regions may be about 3 kΩ. The particular dopants employed to form the active regions 130a-e may depend on the particular layout of the application employing them. For example, if the active regions 130a-130e form a portion of an NMOS transistor, the dopant may be an n-type dopant, such as arsenic, P32, stibium, and/or other n-type dopants. In contrast, if the active regions 130a-e form a portion of a PMOS transistor, the dopant may be a p-type dopant, such as boron, BF2, indium, and/or other p-type dopants. Moreover, the active regions 130a-e may be implanted with the different dopant types within a single embodiment. As shown in FIG. 1, the active region 130a is formed in the p-doped region 115a, the active regions 130b and 130c are formed in the n-doped region 110, and the active regions 130d and 130e are formed in the p-doped region 115b. In one embodiment, the active regions 130a and 130d are offset from the n-doped region by less than about 70 nm. The active regions 130a-130e may be oriented substantially parallel to the longitudinal axes of the doped regions 110, 115a, 115b, and may extend beyond the boundary 125 of a particular SRAM unit cell 120a-i. One or more of the active regions 130a-e may also vary in width relative to others of the active regions 130a-e. For example, the active region 130e may also be substantially wider than one or more of the other active regions 130a-d. In one embodiment, the active region 130e may be wide enough to support more than one transistor device. The gate electrodes 140a-e may comprise one or more patterned and/or selectively deposited layers of polysilicon, W, Ti, Ta, TiN, TaN, Hf, Mo, metal silicide, SiO2, nitrided SiO2, SiOxNy, WSix, V, Nb, MoSix, Cu, Al, carbon nanotubes, high-k dielectrics, alloys thereof, and/or other materials. Exemplary high-k dielectric materials include Ta2O5, HfO2, ZrO2, HfSiON, HfSix, HfSixNy, HfAlO2, NiSix. Such layers may also include portions of the polysilicon and/or silicide layers describe above. Manufacturing processes which may be employed to form the gate electrodes 140a-e include imprint lithography, immersion photolithography, maskless photolithography, chemical-vapor deposition (CVD), plasma-enhanced CVD (PECVD), atmospheric pressure CVD (APCVD), physical-vapor deposition (PVD), atomic layer deposition (ALD), and/or other processes. The process environment during such processing may include hydrogen (H2) and carbon gas reactants, which may be excited by a plasma. The process gas may also include, CH4, C2H6, C3H8, and/or other carbon containing sources. The gate electrodes 140a-e may also include a seed layer comprising Ni, Cr, Nb, V, W, and/or other materials, possibly formed by PVD, ALD, PECVD, APCVD, and/or other processing techniques. The gate electrodes 140a-e may also include or be formed on or over one or more gate dielectric layers. Such gate dielectric layers may comprise SiO2, SiON, HfO, Ta2O5, Al2O3, nitrided oxide, CVD oxide, thermal oxide, a nitrogen-containing dielectric material, a high-k dielectric material, and/or other materials, and may be formed by CVD, PECVD, PVD, ALD, and/or other processes. As shown in FIG. 1, the gate electrode 140a may extend over the active region 130a and the gate electrode 140d may extend over the active region 130d. Moreover, one or more of the gate electrodes 140a-e may be shared gate electrodes, extending over more than one of the active regions 130a-e for supporting more than one transistor device. For example, the gate electrode 140b may extend over the active regions 130a and 130b and the gate electrode 140c may extend over the active regions 130c-e. Furthermore, the gate electrode 140e may extend over the active region 130e such that, because the active region 130e may be configured to support more than one transistor device, the gate electrode 140e may also support more than one transistor device despite extending over only a single active region. The gate electrodes 140a-e, whether or not they are configured as shared gate electrodes, may also extend beyond the boundary 125 of a particular SRAM unit cell 120a-i. Moreover, as in the illustrated embodiment, the gate electrodes 140a-e may also include wider portions, such as where subsequently formed contacts or vias may land. The unit cell boundary 125 for each SRAM unit cell 120a-i may have an aspect ratio greater than about 3.2. The aspect ratio is the ratio of a larger primary dimension (“L” in the illustrated embodiment) of the cell 120a-i to a smaller primary dimension (“W” in the illustrated embodiment). For example, the SRAM unit cell 120e may have a length L ranging between about 0.32 μm and about 8 μm and a width W ranging between about 0.08 μm and about 2 μm, or an aspect ratio ranging between about 3 and about 6. In another embodiment, the SRAM unit cell 120e may have a length L ranging between about 12 nm and about 80 nm and a width W ranging between about 3 nm and about 20 nm. The aspect ratio of the cells 120a-i may also range between about 3 and about 6, and may vary from cell to cell. In another embodiment, the aspect ratio of one, several, or all of the cells 120a-i is greater than about 3.5. Referring to FIG. 2, illustrated is a layout view of the SRAM device 100 shown in FIG. 1 in a subsequent stage of manufacture according to aspects of the present disclosure, wherein a metal layer has been formed over various previously formed features. The metal layer may include one or more layers comprising aluminum, gold, copper, silver, tungsten, titanium, titanium nitride, tantalum, tantalum nitride, alloys thereof, and/or other materials. Although not limited within the scope of the present disclosure, the metal layer may be formed by imprint lithography, immersion photolithography, maskless photolithography, CVD, PECVD, PVD, ALD, and/or other processes. The metal layer may also be formed by selective deposition or blanket deposition followed by a patterning process. In one embodiment, the metal layer is formed by one or more of the processes described above regarding the formation of the gate electrodes 140a-e, and/or comprises one or more of the materials described above regarding possible compositions of the gate electrodes 140a-e. The metal layer may include a write port word line contact 210, a write port bit line contact 215, an interconnect 220, a common, ground potential, or Vss contact (hereafter collectively referred to as a Vss contact) 225, and power supply or Vcc contacts (hereafter collectively referred to as Vcc contacts) 230 and 235. The metal layer may also include interconnects 240, 245, and 250, a write port bit-bar line contact 255, a read port bit line contact 260, and a read port word line contact 265. One or more of the interconnects, such as the interconnect 220, may be substantially L-shaped for interconnect misaligned features. The SRAM device also includes contacts or vias (hereafter collectively referred to as contacts) 270 extending between various components of the metal layer and underlying features. The contacts 270 may be formed by processes similar to those employed to form the metal layer, and may be formed prior to formation of the metal layer. However, in one embodiment, the contacts 270 may be formed by a damascene or dual-damascene process as part of the processes employed to form the metal layer. Many of the contacts 270 land on underlying features to delineate a number of transistors included in the SRAM device 100. In the illustrated embodiment, the SRAM device includes two pass-gate transistors (PG-1 and PG-2), two pull-down transistors (PD-1 and PD-2), two pull-up transistors (PU-1 and PU-2), and two read port transistors (RP-1 and RP-2). Table 1 lists the interconnections made by the contacts 270 to corresponding transistor nodes according the embodiment shown in FIG. 2. Each row in Table 1 indicates the existence of a contact 270 or other interconnection feature. TABLE 1 Metal Layer Component Underlying Component Transistor Node write port word line contact 210 gate electrode 140a PG-1 gate write port bit line contact 215 active region 130a PG-1 source interconnect 220 active region 130a PG-1 drain/PD-1 source interconnect 220 active region 130b PU-1 drain interconnect 220 gate electrode 140c PU-2 gate/PD-2 gate/RP-2 gate Vss contact 225 active region 130a PD-1 drain Vcc contact 230 active region 130b PU-1 source Vcc contact 235 active region 130c PU-2 source interconnect 240 gate electrode 140b PD-1 gate/PU-1 gate interconnect 240 active region 130c PU-2 drain interconnect 240 active region 130d PD-2 source/PG-2 drain interconnect 245 active region 130d PD-2 drain interconnect 245 active region 130e RP-1 source interconnect 245 active region 130e RP-2 drain interconnect 250 gate electrode 140d PG-2 gate write port bit-bar line contact 255 active region 130d PG-2 source read port bit line contact 260 active region 130e RP-1 drain read port bit line contact 260 active region 130e RP-2 source read port word line contact 265 gate electrode 140e RP-1 gate Of course, other features or components may interpose the metal layer and the underlying features for interconnection thereof, either in addition to or in the alternative to one or more of the contacts 270. Interconnection schemes other than that described in Table 1 are also within the scope of the present disclosure. The SRAM device may also include more or fewer transistors and/or contacts 270 than in the illustrated embodiment. Referring to FIG. 3, illustrated is a layout view of the SRAM device 100 shown in FIG. 2 in a subsequent stage of manufacture according aspects of the present disclosure, in which a second metal layer is formed over the first metal layer. In one embodiment, the second metal layer is substantially similar in composition and manufacture to the first metal layer described above. The second metal layer includes a write port word line contact 310, a Vss contact 315, interconnects 320, 325, 330, 335, and 340, a write port word line contact 345, and a read port word line contact 350. The SRAM device also includes contacts 360 extending between various components of the first and second metal layers. Thus, one or more of the contacts 360 (and many other contacts described herein) may be or comprise a landing pad for receiving a subsequently formed contact or via. In one embodiment, the contacts 360 are substantially similar in composition and manufacture to the contacts 270 shown in FIG. 2. Table 2 lists the interconnections made between the first and second metal layers by the contacts 360. Each row in Table 2 indicates the existence of a contact 360 or other interconnection feature. TABLE 2 Metal Layer 2 Component Metal Layer 1 Component write port word line contact 310 write port word line contact 210 Vss contact 315 Vss contact 225 interconnect 320 write port bit line contact 215 interconnect 325 Vcc contact 230 interconnect 325 Vcc contact 235 interconnect 330 write port bit-bar line contact 255 interconnect 335 interconnect 245 interconnect 335 interconnect 245 interconnect 340 read port bit line contact 260 write port word line contact 345 interconnect 250 read port word line contact 350 read port word line contact 265 read port word line contact 350 read port word line contact 265 Of course, other features or components may interpose the first and second metal layers for interconnection thereof, either in addition to or in the alternative to one or more of the contacts 360. Interconnection schemes other than that described in Table 2 are also within the scope of the present disclosure. Referring to FIG. 4, illustrated is a layout view of the SRAM device 100 shown in FIG. 3 in a subsequent stage of manufacture according aspects of the present disclosure, in which a third metal layer is formed over the second metal layer. In one embodiment, the third metal layer is substantially similar in composition and manufacture to the first metal layer described above. The third metal layer includes a write port word line interconnect 410 and a Vss interconnect 420. The SRAM device also includes contacts 430 extending between various components of the second and third metal layers. In one embodiment, the contacts 430 are substantially similar in composition and manufacture to the contacts 270 shown in FIG. 2. Table 3 lists the interconnections made between the second and third metal layers by the contacts 430. Each row in Table 3 indicates the existence of a contact 430 or other interconnection feature. TABLE 3 Metal Layer 3 Component Metal Layer 2 Component write port word line interconnect 410 write port word line contact 310 write port word line interconnect 410 write port word line contact 345 Vss interconnect 420 Vss contact 315 Vss interconnect 420 interconnect 335 Of course, other features or components may interpose the second and third metal layers for interconnection thereof, either in addition to or in the alternative to one or more of the contacts 430. Interconnection schemes other than that described in Table 3 are also within the scope of the present disclosure. Referring to FIG. 5, illustrated is a layout view of the SRAM device 100 shown in FIG. 4 in a subsequent stage of manufacture according aspects of the present disclosure, in which a fourth metal layer is formed over the third metal layer. In one embodiment, the fourth metal layer is substantially similar in composition and manufacture to the first metal layer described above. The fourth metal layer includes a read port word line interconnect 510 and a Vss interconnect 520. The SRAM device also includes contacts 530 extending between various components of the third and fourth metal layers. In one embodiment, the contacts 530 are substantially similar in composition and manufacture to the contacts 270 shown in FIG. 2. Table 4 lists the interconnections made between the third and fourth metal layers by the contacts 530. Each row in Table 4 indicates the existence of a contact 530 or other interconnection feature. TABLE 4 Metal Layer 4 Component Metal Layer 3 Component read port word line write port word line interconnect 510 interconnect 410 Vss interconnect 520 read port word line contact 350 Of course, other features or components may interpose the third and fourth metal layers for interconnection thereof, either in addition to or in the alternative to one or more of the contacts 430. Interconnection schemes other than that described in Table 4 are also within the scope of the present disclosure. After the features shown in FIG. 5 have been formed, the SRAM device 100 may be completed by conventional and/or future-developed processes. For example, additional metal layers may be formed over the fourth metal layer shown in FIG. 5, such as for the further interconnection of the SRAM device 100 with other devices or components, including other SRAM devices, in the chip and/or wafer in which the SRAM device 100 is incorporated. In one embodiment, multiple instances of the SRAM device 100 may be substantially repeated to form an SRAM memory array. The SRAM device 100 described above also includes one or more inter-metal dielectric or other insulating layers interposing the various conductive components. Such insulating layers, each of which may itself comprise multiple insulating layers, may be planarized to provide a substantially planar surface for subsequent processing. The insulating layers may comprise SiO2, fluoride-doped glass (FSG), SiLK™ (a product of Dow Chemical of Michigan), Black Diamond® (a product of Applied Materials of Santa Clara, Calif.), and/or other materials, and may be formed by CVD, ALD, PVD, spin-on coating, and/or other processes. Referring to FIG. 6, illustrated is a circuit diagram of one embodiment of an SRAM device 600 according to aspects of the present disclosure. The SRAM device 600 may be substantially similar to the SRAM device 100 shown in FIG. 5. The SRAM device 600 includes pull-up transistors 610, 615, pull-down transistors 620, 625, pass-gate transistors 630, 635, and read port transistors 640, 645. In one embodiment, the pull-up transistors 610, 615 are PMOS transistors, whereas the pull-down transistors 620, 625, pass-gate transistors 630, 635, and read port transistors 640, 645 are NMOS transistors, although other configurations of NMOS and PMOS transistors are within the scope of the present disclosure. The sources of the pull-up transistors 610, 615 are electrically coupled to a power source (referred to herein as Vcc) 650. The drain of the pull-up transistor 610 is electrically coupled to the source of the pass-gate transistor 630, the source of the pull-down transistor 620, and the gate of the pull-up transistor 615. Similarly, the drain of the pull-up transistor 615 is electrically coupled to the source of the pass-gate transistor 635, the source of the pull-down transistor 625, and the gate of the pull-up transistor 610. The gate of the pull-up transistor 610 is also electrically coupled to the gate of the pull-down transistor 620. Similarly, the gate of the pull-up transistor 615 is also electrically coupled to the gate of the pull-down transistor 625, and is also electrically coupled to the gate of the read port transistor 640. The drains of the pull-down transistors 620, 625 are electrically coupled to a ground, common, or Vss contact (hereafter collectively referred to as a Vss contact) 655. The drain of the read port transistor 640 is also electrically coupled to a Vss contact 657. The drains of the pass-gate transistors 630, 635 are electrically coupled to a read port bit line 660 and a read port bit-bar line 665, respectively. The gates of the pass-gate transistors 630, 635 are electrically coupled to a write port word line 670. The read port transistors 640, 645 are electrically coupled between the Vss contact 657 and a read port bit line 675, wherein the gate of the read port transistor 645 is electrically coupled to a read port word line 680. The read port bit and bit-bar lines 660, 665, the write port word line 670, the read port bit line 675, and the read port word line 680 may extend to other SRAM cells and/or other components, including row and column latch, decoder, and select drivers, control and logic circuitry, sense amps, muxes, buffers, etc. In one embodiment, a maximum capacitance of a write port storage node of the SRAM device 600 is less than about 0.6 farads. Referring to FIG. 7, illustrated is a circuit diagram of another embodiment of the SRAM device shown in FIG. 6, herein designated by the reference numeral 700. The SRAM device 700 may be substantially similar to the SRAM device 100 shown in FIG. 1. The SRAM device 700 is also substantially similar to the SRAM device 600 shown in FIG. 1, with the exception that the read port transistors 640, 645 are replaced with additional pass-gate transistors 710, 715, as well as modifications to the interconnection of transistors with input/output circuitry, as described below. In the embodiment shown in FIG. 7, the drain of the pass-gate transistor 630 is electrically coupled to a first port bit line 720 and the drain of the pass-gate transistor 635 is electrically coupled to a first port bit-bar line 725. The pass-gate transistor 710 is electrically coupled in series between the source of the pull-down transistor 620 and a second port bit line 730, wherein the gate of the pass-gate transistor 710 is electrically coupled to a second port word line 740. Similarly, the pass-gate transistor 715 is electrically coupled in series between the source of the pull-down transistor 625 and a second port bit-bar line 735, wherein the gate of the pass-gate transistor 715 is electrically coupled to the second port word line 740. Referring to FIG. 8, illustrated is a plan view of a portion of an SRAM device manufacturing wafer 800 according to aspects of the present disclosure. The wafer 800 may be employed in the manufacture of the SRAM devices 100, 600, and/or 700 described above. The illustrated portion of the wafer 800 includes doped regions 810 having a first dopant type and doped regions 820, 830 having a second dopant type. For example, the doped regions 810 may be n-doped regions and the doped regions 820, 830 may be p-doped regions. Each doped region 810 may interpose a doped region 820 and a doped region 830. Two or more of the doped regions 810, 820, and 830 may also be substantially parallel. In one embodiment, as shown in FIG. 8, all of the doped regions 810, 820, and 830 are substantially parallel. The pitch between neighboring doped regions 830 may range between about 3 μm and about 5 μm. In one embodiment, the pitch between neighboring doped regions is about 3.6 μm. FIG. 8 also illustrates the formation of SRAM unit cells 840, 845 having an increased packing density. The cells 840, 845 may each have a longitudinal axis that is substantially perpendicular to the longitudinal axes of the doped regions 810, 820, and 830. The cells 840, 845 may also have common or substantially aligned longitudinal axes. Each of the cells 840, 845 may also have substantially equal lengths (L), substantially equal widths (W), and/or substantially equal aspects ratios (L/W). In one embodiment, one or more of the cells 840, 845 have an aspect ratio of at least about 3.2. One of more of the SRAM unit cells 840, 845 may be substantially similar to the SRAM devices 100, 600, and/or 700 described above. The cells 845 may be mirror images or rotated versions of the cells 840. Each of the cells 840, 845 extend from an approximate midpoint of a doped region 820 to an approximate midpoint of a doped region 830, thereby extending over a doped region 810. Thus, each of the cells 840, 845 may include a segment of a doped region 810 spanning the entire width of the doped region 810, a segment of a doped region 820 spanning a portion of the width of the doped region 820, and a segment of a doped region 830 spanning a portion of the width of the doped region 830. In one embodiment, the area of a cell 840, 845 overlying a doped region 830 may be greater than the area overlying a doped region 820 by an amount ranging between about 100% and about 500%. Thus, the present disclosure introduces an SRAM device including a substrate and an SRAM unit cell. The substrate includes an n-doped region interposing first and second p-doped regions. The SRAM unit cell includes: (1) a first pass-gate transistor and a first pull-down transistor located at least partially over the first p-doped region; (2) first and second pull-up transistors located at least partially over the n-doped region; and (3) a second pass-gate transistor, a second pull-down transistor, and first and second read port transistors, all located at least partially over the second p-doped region. A boundary of the SRAM unit cell comprises first and second primary dimensions having an aspect ratio of at least about 3.2. In another embodiment of an SRAM device constructed according to aspects of the present disclosure, the SRAM unit cell includes third and fourth pass-gate transistors located at least partially over the second p-doped region. In one embodiment, an SRAM device of the present disclosure includes a boundary having an aspect ratio of at least about 3.5. The present disclosure also provides an SRAM device in which the SRAM unit cell includes: (1) a first pass-gate transistor and a first pull-down transistor located at least partially over the first p-doped region; (2) first and second pull-up transistors located at least partially over the n-doped region; and (3) a second pass-gate transistor, a second pull-down transistor, and first and second read port transistors, all located at least partially over the second p-doped region. Such an embodiment may also include a first transistor active region implanted in the first p-doped region and extending between source/drain contacts of the first pass-gate transistor and the first pull-down transistor. A second transistor active region may also be implanted in the second p-doped region and extend between source/drain contacts of the second pass-gate transistor and the second pull-down transistor. A method of manufacturing an SRAM device is also introduced in the present disclosure. In one embodiment, the method includes providing a substrate having a first doped region of a first dopant type, wherein the first doped region interposes second and third doped regions of a second dopant type. First and second pull-up transistors are formed at least partially over the first doped region. A first pass-gate transistor and a first pull-down transistor are formed at least partially over the second doped region. A second pass-gate transistor, a second pull-down transistor, and first and second read port transistors, are also formed at least partially over the third doped region. The first and second pass-gate, pull-down, pull-up, and read port transistors form an SRAM unit cell, wherein a boundary of the SRAM unit cell has first and second primary dimensions forming an aspect ratio of at least about 3.2. The present disclosure also introduces an integrated circuit device including, in one embodiment, a substrate having a plurality of first doped regions of a first dopant type, a plurality of second doped regions of a second dopant type, and a plurality of third doped regions of the second dopant type. Each of the first doped regions interpose one of the plurality of second doped regions and one of the plurality of third doped regions. The integrated circuit device also includes a plurality of SRAM devices. Each of the SRAM devices includes first and second pull-up transistors located at least partially over one of the plurality of first doped regions. The SRAM devices also include a first pass-gate transistor and a first pull-down transistor located at least partially over one of the plurality of second doped regions adjacent the one of the plurality of first doped regions. The SRAM devices also include a second pass-gate transistor, a second pull-down transistor, and first and second read port transistors, all located at least partially over one of the plurality of third doped regions adjacent the one of the plurality of first doped regions and opposite the one of the plurality of second doped regions. The first and second pass-gate, pull-down, pull-up, and read port transistors form an SRAM unit cell, wherein a boundary of the SRAM unit cell has first and second primary dimensions forming an aspect ratio of at least about 3.2. The integrated circuit device also includes a plurality of interconnects interconnecting ones of the first and second pull-up, pass-gate, pull-down, and read port transistors. Another embodiment introduces an SRAM device including at least eight transistors, wherein two of the transistors may be adapted for input/output (I/O) with at least one feature having channel dimensions substantially larger than the channel dimensions of the feature of the SRAM device. Alternatively, the SRAM device may further include at least eight transistors, wherein two of the transistors may be connected in series and are adapted for input/output (I/O), having channel dimensions substantially larger than the channel dimensions of the other transistors in the SRAM device. The foregoing has outlined features of several embodiments so that those skilled in the art may better understand the detailed description that follows. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure. | <SOH> BACKGROUND <EOH>The present disclosure relates generally to static random access memory (SRAM) devices and, more specifically, to an SRAM device having a high aspect ratio cell boundary. The physical dimension of a feature on a chip is referred to as “feature size.” Reducing the feature size on a chip permits more components to be fabricated on each chip, and more components to be fabrication on each silicon wafer, thereby reducing manufacturing costs on a per-wafer and a per-chip basis. Increasing the number of components in each chip can also improve chip performance because more components may become available to satisfy functional requirements. SRAM devices are one type of device that may undergo such scaling to reduce manufacturing costs. SRAM is random access memory that retains data bits in its memory as long as power is being supplied. Unlike dynamic random access memory (DRAM), SRAM does not have to be periodically refreshed. SRAM also provides faster access to data than DRAM. Thus, for example, SRAM is frequently employed in a computer's cache memory, or as part of the random access memory digital-to-analog converters in video cards. However, SRAM is more expensive than other types of memory. Thus, SRAM designers and manufacturers continually strive to reduce the costs of manufacturing SRAM devices. The scaling of features sizes discussed above is one of the means to achieve such cost reduction. However, scaling feature sizes is not the only means available to reduce SRAM manufacturing costs. For example, modifying the layout of features within an SRAM chip to further increase the packing density of SRAM cells within each chip can also reduce manufacturing costs. Accordingly, what is needed in the art is an SRAM device and method of manufacture thereof that addresses the above discussed issues. | <SOH> BRIEF DESCRIPTION OF THE DRAWINGS <EOH>Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. FIG. 1 illustrates a layout view of one embodiment of an SRAM device in an intermediate stage of manufacture according to aspects of the present disclosure. FIG. 2 illustrates a layout view of the SRAM device shown in FIG. 1 in a subsequent stage of manufacture. FIG. 3 illustrates a layout view of the SRAM device shown in FIG. 2 in a subsequent stage of manufacture. FIG. 4 illustrates a layout view of the SRAM device shown in FIG. 3 in a subsequent stage of manufacture. FIG. 5 illustrates a layout view of the SRAM device shown in FIG. 4 in a subsequent stage of manufacture. FIG. 6 illustrates a circuit diagram of another embodiment of an SRAM device according to aspects of the present disclosure. FIG. 7 illustrates a circuit diagram of another embodiment of the SRAM device shown in FIG. 6 . FIG. 8 illustrates a plan view of a portion of an SRAM device manufacturing wafer according to aspects of the present disclosure. detailed-description description="Detailed Description" end="lead"? | 20040405 | 20070619 | 20050609 | 72153.0 | 1 | SEFER, AHMED N | SRAM DEVICE HAVING HIGH ASPECT RATIO CELL BOUNDARY | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,818,181 | ACCEPTED | Systems for self-servowriting with multiple passes per servowriting step | The amount of position error written into a servo burst pattern can be reduced by using additional media revolutions to write the pattern. Where servo bursts are used to define a position on the media, trimming a first burst and writing a second burst on separate revolutions of the media will result in a different amount of position error being written into each burst. The end result will be a reduction in the overall error in position information. In order to further reduce the position error given by a combination of bursts, each burst also can be trimmed and/or written in multiple passes. The overall error in position should decrease as the number of passes used to write a burst combination increases. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims. | 1. A system for writing position information to a rotating medium, comprising: a rotatable medium capable of storing information written to the rotatable medium; a write element capable of writing information to the rotatable medium; and a control mechanism adapted to rotate the rotatable medium and position the write element relative to the rotatable medium, such that the write element can: write a first servo burst during a first servowriting step of the write element over the rotatable medium; trim the first servo burst during a first pass of a second servowriting step of the write element; and write a second servo burst during a second pass of the second servowriting step of the write element, wherein the first servo burst and second servo burst each have a substantially common edge that can be used to determine the position of the write element during a subsequent pass over those servo bursts. 2. A system according to claim 1, wherein: the rotatable medium is selected from the group consisting of magnetic disks, optical disks, and laser-recordable disks. 3. A system according to clam 1, wherein: the first servo burst and second servo burst each have an edge that is positioned approximately along a track line, the track line extending circumferentially about the disk. 4. A system according to claim 1, further comprising: a read element adapted to read the first servo burst and second servo burst on a subsequent pass over the rotatable medium. 5. A system according to claim 4, further comprising: a read/write head containing the read element and the write element. 6. A system according to claim 5, further comprising: read circuitry adapted to accept information from the read element and determine the position of the read/write head. 7. A system according to claim 1, wherein: the write element is further adapted to trim the first servo burst to have a width approximately equal to the width of a track of servo data. 8. A system according to claim 1, wherein: the write element is adapted to write the first and second servo bursts in a servo wedge on the rotatable medium. 9. A system according to claim 1, wherein: the write element executes the second pass of the second servowriting step before the first pass of the second servowriting step. 10. (canceled) 11. (canceled) 12. (canceled) 13. (canceled) 14. (canceled) 15. A system for writing position information to a magnetic disk, comprising: a magnetic disk capable of storing information written to the magnetic disk; a write element capable of writing information to the magnetic disk; and a control mechanism adapted to rotate the magnetic disk and position the write element relative to the magnetic disk, such that the write element can: write a first servo burst during a first servowriting step of the write element over a magnetic hard disk; trim the first servo burst during a first pass of a second servowriting step of the write head, the first servo burst being trimmed so as to have a trimmed edge in about a predetermined position on the magnetic disk; and write a servo burst during a second pass of the second servowriting step of the write head, wherein the trimmed edge of the first servo burst and an adjacent edge of the second servo burst define a position that can be used to adjust the radial location over the disk of the write head during subsequent passes over those bursts. 16. A system for writing position information to a magnetic disk, comprising: means for writing a first servo burst during a first servowriting step of a write head over a magnetic hard disk; means for trimming the first servo burst during a first pass of a second servowriting step of the write head, the first servo burst being trimmed so as to have a trimmed edge in about a predetermined position on the magnetic disk; and means for writing a servo burst during a second pass of the second servowriting step of the write head, wherein the trimmed edge of the first servo burst and an adjacent edge of the second servo burst define a position that can be used to adjust the radial location over the disk of the write head during subsequent passes over those bursts. 17. A system for writing position information to a rotating medium in order to reduce repeatable runout, comprising: a rotatable medium capable of storing information written to the rotatable medium; a write element capable of writing information to the rotatable medium; and a control mechanism adapted to rotate the rotatable medium and position the write element relative to the rotatable medium, such that the write element can: write a first servo burst during a first servowriting step of the write element over the rotatable medium; trim the first servo burst during a first pass of a second servowriting step of the write element; and write a second servo burst during a second pass of the second servowriting step of the write element, wherein the first servo burst and second servo burst each have substantially common edge that can be used to determine the position of the write element in order to reduce repeatable runout. 18. A method for writing position information to a rotating medium, comprising: writing a first servo burst during a first servowriting step of a write element over a rotating medium; trimming the first servo burst during a first pass of a second servowriting step of the write element; and writing a second servo burst during a second pass of the second servowriting step of the write element, wherein the first servo burst and second servo burst each have a substantially common edge that can be used to determine the position of the write element during a subsequent pass over those servo bursts. 19. A method according to claim 18, further comprising: using the trimmed edge of the first servo burst and an adjacent edge of the second servo burst to determine the position of the write element. 20. A method according to claim 18, including at least one of: having the width of the first servo burst after trimming be approximately the width of a track of servo data; containing the first and second servo bursts in a servo wedge on the rotating medium; having the trimmed edge of the first servo burst and an adjacent edge of the second servo burst define the position of a centerline of a data track on the rotating medium; and having the second pass of the second servowriting step occur before the first pass of the second servowriting step. 21. A method for writing servo information to a magnetic disk, comprising: writing a first servo burst during a first servowriting step of a write head over a magnetic hard disk; trimming the first servo burst during a first pass of a second servowriting step of the write head, the first servo burst being trimmed so as to have a trimmed edge in about a predetermined position on the magnetic disk; and writing a servo burst during a second pass of the second servowriting step of the write head, wherein the trimmed edge of the first servo burst and an adjacent edge of the second servo burst define a position that can be used to adjust the radial location over the disk of the write head during subsequent passes over those bursts. 22. A method for writing position information to a rotating medium in order to reduce repeatable runout, comprising: writing a first servo burst during a first servowriting step of a write element over a rotating medium; trimming the first servo burst during a first pass of a second servowriting step of the write element; and writing a second servo burst during a second pass of the second servowriting step of the write element, wherein the first servo burst and second servo burst each have a substantially common edge that can be used to determine the position of the write element in order to reduce repeatable runout. | CLAIM OF PRIORITY This application is a continuation of U.S. patent application Ser. No. 10/420,452, filed Apr. 22, 2003, which claims benefit of U.S. Provisional Patent Application No. 60/436,709, filed Dec. 27, 2002, both of which are incorporated herein by reference. CROSS-REFERENCE TO RELATED APPLICATIONS The following applications are cross-referenced and incorporated herein by reference: U.S. Provisional Patent Application No. 60/436,743 entitled “Methods for Multi-Pass Self-Servowriting,” by Richard M. Ehrlich, filed Dec. 27, 2002 (Attorney Docket No. PANAP-01017US1). U.S. patent application Ser. No. 10/420,127 entitled “Methods for Self-Servowriting with Multiple Passes Per Servowriting Step,” by Richard M. Ehrlich, filed Apr. 22, 2003 (Attorney Docket No. PANAP-01017US3). U.S. Patent Application No. 10/______, entitled “Methods for Self-Servowriting With Multiple Passes Per Servowriting Step,” by Richard M. Ehrlick, filed April ______, 2004 (Attorney Docket No. PANAP-01017USB). U.S. Provisional Patent Application No. 60/436,712 entitled “Systems for Self-Servowriting Using Write-Current Variation,” by Richard M. Ehrlich, filed Dec. 27, 2002 (Attorney Docket No. PANAP-01018US0). U.S. Provisional Patent Application No. 60/436,703 entitled “Methods for Self-Servowriting Using Write-Current Variation,” by Richard M. Ehrlich, filed Dec. 27, 2002 (Attorney Docket No. PANAP-01018 US1). U.S. patent application Ser. No. 10/420,076 entitled “Systems for Self-Servowriting Using Write-Current Variation,” by Richard M. Ehrlich, filed Apr. 22, 2003 (Attorney Docket No. PANAP-01018US2). U.S. patent application Ser. No. 10/420,498 entitled “Methods for Self-Servowriting Using Write-Current Variation,” by Richard M. Ehrlich, filed Apr. 22, 2003 (Attorney Docket No. PANAP-01018US3). U.S. Patent Application No. 10/______, entitled “Systems for Self-Servowriting Using Write-Current Variation,” by Richard M. Ehrlich, filed April ______, 2004 (Attorney Docket No. PANAP-01018USA). U.S. Patent Application No. 10/______ entitled “Methods for Self-Servowriting Using Write-Current Variation,” by Richard M. Ehrlich, filed April ______, 2004 (Attorney Docket No. PANAP-01018USB). FIELD OF THE INVENTION The present invention relates to servowriting processes and devices. BACKGROUND Advances in data storage technology have provided for ever-increasing storage capability in devices such as DVD-ROMs, optical drives, and disk drives. In hard disk drives, for example, the width of a written data track has decreased due in part to advances in read/write head technology, as well as in reading, writing, and positioning technologies. More narrow data tracks result in higher density drives, which is good for the consumer but creates new challenges for drive manufacturers. As the density of the data increases, the tolerance for error in the position of a drive component such as a read/write head decreases. As the position of such a head relative to a data track becomes more important, so too does the placement of information, such as servo data, that is used to determine the position of a head relative to a data track. BRIEF SUMMARY Systems and methods in accordance with the present invention take advantage of multiple passes in servowriting and self-servowriting applications. These additional passes allow patterns such as servo burst pairs to be written and/or trimmed on separate passes. The additional passes reduce the written runout, as the average misplacement decreases when the number of passes increases. Each burst in a servo pattern can also be written and/or trimmed in multiple passes. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing components of a disc drive that can be used in accordance with embodiments of the present invention. FIG. 2 is a diagram showing an example of a data and servo format for a disk in the drive of FIG. 1. FIG. 3 is a diagram showing servo information that can be written to the tracks shown in FIG. 2. FIGS. 4(a)-(f) are diagrams of a servo-burst pattern being written over a progression of servowriting steps. FIGS. 5 and 6 are diagrams of a servo-burst pattern being written over a progression of servowriting steps, wherein there is a head misplacement on the second step. FIG. 7 is a diagram of a servo-burst pattern being written over a progression of servowriting steps using multiple passes in accordance with one embodiment of the present invention. FIG. 8 is a diagram of a servo-burst pattern being written over a progression of servowriting steps using multiple passes in accordance with a second embodiment of the present invention. FIG. 9 is flowchart for a method that can be used with to write the patterns of FIGS. 7 and 8. DETAILED DESCRIPTION Systems and methods in accordance with one embodiment of the present invention can be used when servowriting, or self-servowriting, a rotatable storage medium in a data storage device, such as a hard disk drive. For example, a typical disk drive 100, as shown in FIG. 1, includes at least one magnetic disk 102 capable of storing information on at least one of the surfaces of the disk. A closed-loop servo system can be used to move an actuator arm 106 and data head 104 over the surface of the disk, such that information can be written to, and read from, the surface of the disk. The closed-loop servo system can contain, for example, a voice coil motor driver 108 to drive current through a voice coil motor (not shown) in order to drive the actuator arm, a spindle motor driver 112 to drive current through a spindle motor (not shown) in order to rotate the disk(s), a microprocessor 120 to control the motors, and a disk controller 118 to transfer information between the microprocessor, buffer, read channel, and a host 122. A host can be any device, apparatus, or system capable of utilizing the data storage device, such as a personal computer or Web server. The drive can contain at least one processor, or microprocessor 120, that can process information for the disk controller 118, read/write channel 114, VCM driver 108, or spindle driver 112. The microprocessor can also include a servo controller, which can exist as an algorithm resident in the microprocessor 120. The disk controller 118, which can store information in buffer memory 110 resident in the drive, can also provide user data to a read/write channel 114, which can send data signals to a current amplifier or preamp 116 to be written to the disk(s) 102, and can send servo and/or user data signals back to the disk controller 118. The information stored on such a disk can be written in concentric tracks, extending from near the inner diameter of the disk to near the outer diameter of the disk 200, as shown in the example disk of FIG. 2. In an embedded servo-type system, servo information can be written in servo wedges 202, and can be recorded on tracks 204 that can also contain data. In a system where the actuator arm rotates about a pivot point such as a bearing, the servo wedges may not extend linearly from the inner diameter (ID) of the disk to the outer diameter (OD), but may be curved slightly in order to adjust for the trajectory of the head as it sweeps across the disk. The servo information often includes bursts of transitions called “servo bursts.” The servo information can be positioned regularly about each track, such that when a data head reads the servo information, a relative position of the head can be determined that can be used by a servo processor to adjust the position of the head relative to the track. For each servo wedge, this relative position can be determined in one example as a function of the target location, a track number read from the servo wedge, and the amplitudes or phases of the bursts, or a subset of those bursts. The position of a head or element, such as a read/write head or element, relative to the center of a target track, will be referred to herein as a position-error signal (PES). For example, a centerline 300 for a given data track can be “defined” relative to a series of bursts, burst edges, or burst boundaries, such as a burst boundary defined by the lower edge of A-burst 302 and the upper edge of B-burst 304 in FIG. 3. The centerline can also be defined by, or offset relative to, any function or combination of bursts or burst patterns. This can include, for example, a location at which the PES value is a maximum, a minimum, or a fraction or percentage thereof. Any location relative to a function of the bursts can be selected to define track position. For example, if a read head evenly straddles an A-burst and a B-burst, or portions thereof, then servo demodulation circuitry in communication with the head can produce equal amplitude measurements for the two bursts, as the portion of the signal coming from the A-burst above the centerline is approximately equal in amplitude to the portion coming from the B-burst below the centerline. The resulting computed PES can be zero if the radial location defined by the A-burst/B-burst (A/B) combination, or A/B boundary, is the center of a data track, or a track centerline. In such an embodiment, the radial location at which the PES value is zero can be referred to as a null-point. Null-points can be used in each servo wedge to define a relative position of a track. If the head is too far towards the outer diameter of the disk, or above the centerline in FIG. 3, then there will be a greater contribution from the A-burst that results in a more “negative” PES. Using the negative PES, the servo controller could direct the voice coil motor to move the head toward the inner diameter of the disk and closer to its desired position relative to the centerline. This can be done for each set of burst edges defining the shape of that track about the disk. The PES scheme described above is one of many possible schemes for combining the track number read from a servo wedge and the phases or amplitudes of the servo bursts. Many other schemes are possible that can benefit from embodiments in accordance with the present invention. A problem that exists in the reading and writing of servo patterns involves the misplacement, or offset, of a read/write head with respect to the ideal and/or actual position of a track. It is impossible to perfectly position a head with respect to a track for each rotation of a disk, as there is almost always a noticeable offset between the desired position and the actual position of the head with respect to the disk. This can cause problems when writing servo patterns, as each portion of the pattern can be slightly misplaced. This can lead to what is referred to as written-in runout. Written-in runout can be thought of as the offset between the “actual” centerline, or desired radial center, of a track and the centerline that would be determined by a head reading the written servo pattern. Written-in runout can lead to servo performance problems, wasted space on a disk and, in a worst case, unrecoverable or irreparably damaged data. Systems and methods in accordance with embodiments of the present invention overcome deficiencies in prior art servowriting and self-servowriting systems by taking advantage of additional passes when writing servo information. The use of additional passes for the writing and/or trimming of servo burst patterns, for example, can provide for a low written-in runout in a servo pattern, but at the cost of some time-penalties in the servowriting and/or self-servowriting operations. The additional passes can achieve this reduced written-in runout by effectively making the written-in runout be the average of multiple servowriting passes. The time penalty due to the additional passes is small in self-servowriting processes, since a drive typically already spends many revolutions at each servowriting position in determination of the written-in runout of the reference pattern. One or two extra revolutions will only increase the self-servowriting time by a small fraction, such as on the order of about 16%-32%. Used with a standard servowriting process, each additional pass can add on the order of 75%. FIGS. 4(a)-4(f) depict the progression of several steps of an exemplary servowriting process. The pattern shown in these figures is commonly referred to in the trade as a 3-pass-per-track, trimmed-burst pattern, for reasons described below. However, it is to be understood that for this specification the appropriate term is “3-step-per-track” or “3-servowriting-step-per-track”. That is to say that each servowriting step can include one or multiple passes and each track is defined by one or multiple servowriting steps. Each figure depicts a small portion of the surface of a disk. This portion can contain several servo tracks, extending radially on the disk and vertically in the figures, and can cover the space of a single servo wedge, circumferentially on the disk and horizontally in the figures. A typical drive can have tens of thousands of servo tracks, and over one hundred wedges per revolution. In the figures, the patterned areas indicate portions of the surface of the disk that have been magnetized in one direction. Areas without patterning have been magnetized in another direction, typically in a direction opposite to that of the patterned areas. For drives which use longitudinal recording, the first direction will be substantially in the circumferential direction, and the second direction will be opposite to the first. For drives which use perpendicular recording (also referred to as “vertical recording”), the two directions are perpendicular to the plane of the disk. These simplified figures do not show effects of side-writing of the write element, which can produce non-longitudinal magnetization and erase bands. Such effects are not of primary importance to the discussion herein. In FIG. 4(a), the result of a single servowriting step is shown. From that step, the servowriting head (passing from left to right in the figure) has written an exemplary servo pattern containing a preamble, followed by a servo-address mark (SAM), followed by an INDEX-bit, and then a track number, as is known in the art. Other information can be written to the servo pattern in addition to, or in place of, the information shown in FIG. 4(a). An INDEX-bit, for example, is one piece of information that can be used to give the servo an indication of which wedge is wedge-number zero, useful for determining circumferential position. The track number, which can be a graycoded track-number, can later be used by the servo to determine the coarse radial position of the read/write (R/W) head. Following the track number, the head writes one of four servo bursts, in this case what will be referred to as a C-burst, which can later be used by a servo to determine the fine (fractional track) radial position of a R/W head. The number of servo bursts used can vary with servo pattern. The burst that is written can be, for example, the one that is in-line with the digital information. The width of the written track can be determined by the magnetic write-width of the write element of the servowriting head. FIG. 4(b) shows the result of a second step of the servowriting process. All that has been added in the second step is an additional burst, in this case referred to as an A-burst. The A-burst is displaced longitudinally from both the digital information and the C-burst, to prevent any overlap in the longitudinal direction. The A-burst is also displaced by approximately one-half of a servo-track in the radial direction. FIG. 4(c) shows the magnetization pattern after three steps of the servowriting process. The new portion of the pattern has been written with the servowriting head displaced another half servo track radially, for a total displacement of one servo-track, or two-thirds of a data-track, from the position of the head during the first servowriting step. New digital information has been written, including the same preamble, SAM, and INDEX-bit, as well as a new track number. A D-burst was added during the third servowriting step, and the C-burst was “trimmed.” The C-burst was trimmed by “erasing” the portion of the C-burst under the servowriting head as the head passed over the burst on the third servowriting step. As long as the servowriting head is at least two-thirds of a data-track in radial extent, the digital information will extend across the entire radial extent of the servowritten pattern. This trimming of the C-burst and writing of the D-burst created a common edge position or “boundary” between the two bursts. In FIG. 4(d), a B-burst has been added and the A-burst trimmed in the fourth step of the servowriting process. At a point in time after the servowriting is complete, such as during normal operation of the disk drive, the upper edge of the B-burst and the lower edge of the A-burst can be used by the servo, along with the graycoded track-number whose radial center is aligned with the burst edges, to determine the R/W head position when it is in the vicinity of the center of that servo track. If a reader evenly straddles the A-burst and the B-burst, the amplitude of the signals from the two bursts will be approximately equal and the fractional Position-Error Signal (PES) derived from those bursts will be about 0. If the reader is off-center, the PES will be non-zero, indicating that the amplitude read from the A-burst is either greater than or less than the amplitude read from the B-burst, as indicated by the polarity of the PES signal. The position of the head can then be adjusted accordingly. For instance, negative PES might indicate that the amplitude read from the A-burst is greater than the amplitude read from the B-burst. In this case, the head is too far above the center position (using the portion of the pattern in the figure) and should be moved radially downward/inward until the PES signal is approximately 0. It should be noted that for other portions of the pattern a B-burst could be above an A-burst, resulting in a negative amplitude contribution coming from the A-burst. Other burst-demodulation schemes have been proposed which determine the PES as a function of more than two burst amplitudes. Two examples of such schemes are disclosed in U.S. Pat. No. 6,122,133 and U.S. Pat. No. 5,781,361, which examples are incorporated herein by reference. Such schemes would also benefit from the current invention. FIGS. 4(e) and 4(f) show the results of subsequent steps of the servowriting process, which has produced a number of servo tracks. After the first step in this process, each subsequent step writes one servo burst in a wedge and trims another. Every second step also writes digital information, including the SAM and track number. Between servowriting steps, the servowriting head is stepped by one-half servo track radially, either toward the inner diameter (ID) or outer diameter (OD) of the disk, depending on the radial direction used to write the servo information. A seek typically takes anywhere from one quarter to one half of the time it takes for the disk to make one revolution. The process of writing the servo pattern for each servowriting step typically takes one full revolution to write all of the wedges for that step. Using this algorithm, then, servowriting can take about 1.25-1.5 revolutions per servowriting step. Since there are two servowriting steps per servo-track in this example, and 1.5 servo tracks per data-track, such a process requires 3 servowriting steps per data-track, or 3.75-4.5 revolutions per data-track. For purposes of subsequent discussion only, it will be assumed that the process takes 4 revolutions per data-track. A disk drive can have tens of thousands of data tracks. With 100,000 data-tracks and a spin-speed of 5400 RPM (90 Hz), for example, the process would take 4,444 seconds, or about 75 minutes. If the process is carried out on an expensive servowriter, this can add substantially to the cost of the drive. Thus, drive manufacturers are motivated to use self-servowriting techniques to reduce or eliminate the time that a drive must spend on a servowriter. One such technique uses a media-writer to write servo patterns on a stack of disks. Each disk is then placed in a separate drive containing multiple blank disks, such that the drive can use the patterned disk as a reference to re-write servo patterns on all of the other disk surfaces in the drive, as well as writing a servo pattern on the patterned surface, if desired. The media-writer can be an expensive instrument, and it may still take a very long time to write a reference pattern on the stack of disks. However, if a stack contains 10 blank disks, for example, then the media-writer can write the reference pattern for 10 drives in the time that it would have taken to servowrite a single drive. This scheme is a member of a class of self-servowriting techniques commonly known as “replication” self-servowriting. A typical replication process, in which a drive servos on the reference pattern and writes final servo patterns on all surfaces, takes place while the drive is in a relatively inexpensive test-rack, connected to only a power-supply. The extra time that it takes is therefore usually acceptable. Another class of self-servowriting techniques is known as “propagation” self-servowriting. Schemes in this class differ from those in the “replication” class in the fact that the wedges written by the drive at one point in the process are later used as reference wedges for other tracks. These schemes are thus “self-propagating”. Typically, such schemes require a R/W head that has a large radial offset between the read and write elements, so that the drive can servo with the read element over previously-written servo wedges while the write element is writing new servo wedges. In one such application, a servowriter is used for a short time to write a small “guide” pattern on a disk that is already assembled in a drive. The drive then propagates the pattern across the disk. In this type of self-servowriting operation, previously written tracks can later serve as reference tracks. Many of the self-servowriting techniques, including those described above, require considerably more than four disk revolutions per data-track written, as the drive must spend considerable time at the start of each servowriting step determining the written-in runout of the corresponding reference track, so that the servowriting head can be prevented from following that runout while writing the final servo pattern. Techniques exist which allow tracks of servo information to be made substantially circular, despite the fact that the reference information is not perfectly circular. The information used to remove written-in runout from the track can be calculated, in one approach, by examining a number of parameters over a number of revolutions. These parameters can include wedge offset reduction field (WORF) data values. WORF data can be obtained, for example, by observing several revolutions of the position error signal (PES) and combining the PES with servo loop characteristics to estimate the written-in runout, such as of the reference track. It is also possible to synchronously average the PES, and combine the synchronously-averaged PES with servo loop characteristics to estimate the written-in runout. Various measurements can be made, as are known in the art, to characterize servo loop characteristics. Because the servo typically suffers both synchronous and non-synchronous runout, any measurement intended to determine the synchronous runout will be affected by the non-synchronous runout. If many revolutions of PES data are synchronously averaged, the effects of the non-synchronous runout can lessen, leaving substantially only synchronous runout. This allows better determination of, and subsequent elimination of, the written-in runout. Averaging many revolutions of PES data, however, can add significantly to the time required for determination of the written-in runout. Process engineers may need to balance the cost and benefit of additional revolutions of PES data collection in determination of WORF values. The computed written-in runout values for each servo wedge can be written into the servo wedges themselves for later use by the servo, or can be kept in drive microcontroller memory for immediate use. During a self-servowriting operation, the drive may use the latter option by calculating the written-in runout on a reference track and applying it to the servo by the use of a table in microcontroller memory. Additional revolutions of PES measurements for the reference track can be used to reduce the effects of non-synchronous, or repeatable, runout. As previously described, techniques for determining and removing written-in runout of a track will hereinafter be referred to as WORF technology. If, for example, a drive spends 5 revolutions to determine the written-in runout of each reference track before writing the corresponding final wedges, that would add 15 revolutions to the writing time of each data-track (5 extra revolutions per servowriting step, times 3 servowriting steps per data-track), bringing the total time per data-track to 19 revolutions. Even though the self-servowriting time may be as much as about five times as long as the time necessary to servowrite a drive on a servowriter (19 revolutions/data-track, versus 4 revolutions/data-track), self-servowriting is likely to be a less expensive alternative due to the expense of servowriters, as well as the fact that servowriting operations on a servowriter generally must be performed in a clean-room environment. Also, as track-densities get higher it becomes more difficult for an external device such as an actuator push-pin to control the position of the R/W heads accurately enough to produce a servo pattern with sufficiently small written-in runout. The expense of servowriting also rises in proportion to the number of tracks on a drive. FIGS. 4(a)-(f), described above, show an idealized servowriting process in which the radial placement of the writer is virtually perfect during servowriting. In reality, the writer placement will not be perfect, even if the written-in runout of the reference pattern is completely removed, due to non-synchronous positioning errors. There are several sources of non-synchronous runout, which is commonly referred to in the industry as NRRO, or Non-Repeatable Runout. If the servowriting head suffers non-synchronous runout while writing servo wedges, that runout will be written into those wedges. Such a result is illustrated in FIGS. 5 and 6. For the sake of simplicity, only A and B bursts are shown, leaving out the digital information and other bursts. In FIG. 5, the servowriter head 402 in a first servowriting step 400 writes an A-burst. In FIG. 6, the head 508 in a second servowriting step is offset, or mis-placed, a distance from its ideal position. For example, the ideal placement 502 of the top edge of the writer, and therefore the ideal placement of the servo track centerline, is shown a distance from the actual placement 500 of the top edge of the writer 508. This separation is the written-in runout 506. An algorithm such as a typical quadrature servo detection algorithm can be used to determine the fractional track position of the R/W head by comparing the amplitudes of two bursts that are 180 Degrees out of phase with one another, such as the A-burst and B-burst in FIG. 8. Because existing servowriting processes involve trimming the A burst at the same time the B burst is written, any mis-placement of the writer during that revolution will result in equal mis-placement of their common edges. The written-in runout of that wedge, or the mis-placement of the center of the servo track, therefore will be equal to the mis-placement suffered by the writer at the time of writing of the wedge. If the only runout suffered by the writer is NRRO (i.e., if the written-in runout of the reference wedges is completely eliminated by the use of WORF technology), then the Root-Mean-Square (RMS) written-in runout will be equal to the RMS NRRO suffered by the writer during the servowriting process. FIG. 7 depicts a process in accordance with one embodiment of the present invention by which the RMS written-in runout can be substantially reduced, at the cost of an extra revolution of the disk for each servowriting step. For such a servowriting operation, the writing of the B burst and the trimming of the A burst occur on separate revolutions of the disk (i.e., on separate passes) with the A burst and the B burst having a substantially common edge as an exactly common edge is generally impractical. The mis-placement of the upper edge of the B burst and the lower edge of the A burst, each of which are determined by the mis-placement of the writer during the corresponding revolutions of the disk, are quasi-independent random variables. If the runout suffered by the writer is indeed non-synchronous (NRRO), then the mis-placements of those two burst edges should not be the same from one revolution to the next. The mis-placement of the centerline of the servo track will be equal to the average of the misplacement of the upper edge of the B-burst and the lower edge of the A-burst. For example, in the first servowriting step 600 of FIG. 7 the head 606 writes an A-burst. In a first pass of the second servowriting step 602, the head 606 writes a B-burst. The head is displaced a first distance 608 when writing the B-burst. In a second pass of the second servowriting step 604, the head is displaced a different distance 610 from the expected position when trimming the A-burst, leaving a smaller written-in runout 612 than would have occurred had the A-burst been trimmed and the B-burst written in a single pass of the second servowriting step 602 (which would have been approximately equal to the misplacement 608 on that pass). The A-burst also could have been trimmed before writing the B-burst. It is well known that the average of two un-correlated random variables of RMS magnitude, r0, as well as a mean value of zero, has an RMS magnitude of: r0{square root}{square root over (2)}. Whether or not the two misplacements are truly un-correlated depends upon the spectrum of the NRRO. Very low frequency NRRO components may have some correlation from revolution to revolution, but most NRRO components can be essentially un-correlated from one revolution to the next. Thus, by spending one extra revolution for each servowriting step, the servowriting process can achieve about a 29% reduction in the resulting written-in runout. This approach can be extended, as shown in FIG. 8. On a second servowriting step 700, in which a B-burst is written, the head 714 has a first mis-placement 706. At the cost of yet another revolution, the trimming of the A burst can be done in two separate revolutions, trimming half of the burst in each revolution. On a second pass of the second servowriting step 702, half of the A-burst is trimmed with a second mis-placement 708. On a third pass of the second servowriting step 704, the other half of the A-burst is trimmed with a third mis-placement 710. The written-in runout 712 is then even smaller when three mis-placements are averaged. The track centerline being determined by the un-correlated writer misplacement over three separate revolutions can result in an additional reduction in written-in runout of about 13%. The concept can be further extended by trimming the A-burst in additional passes, such as by trimming a third of the A-burst in each of three passes. The written-in runout also can be reduced by writing the B-burst in multiple passes, if the servowriting system is capable of writing magnetic transitions with very high timing coherence from revolution to revolution (i.e., it is capable of lining up the transitions from two separate revolutions very accurately). For example, the B-burst can be written by writing a third of the burst in each of three separate passes. The writing passes and trimming passes can involve doing all the writing then all the trimming, all the trimming then all the writing of new bursts, or alternating trimming and writing. If the separate portions of the B-burst are not circumferentially lined up very accurately, though, a burst-amplitude demodulation scheme could give an inaccurate measurement of the overall amplitude of the burst, and can actually increase the written-in runout. If the B-burst were to be split into two separate B-bursts, with each being demodulated separately and the amplitudes being averaged, then this would not be a problem. This could require a servo detection system that can accommodate more bursts, as well as additional overhead on the disk for the necessary space between the sub-bursts. If the techniques shown in FIG. 7 or 8 are used, there is no need for extremely high coherency in servowriting. If the embodiment depicted in FIG. 7 is applied to a standard servowriting operation done on a servowriter, one extra revolution per servowriting step is required. With three servowriting steps per data-track, this will nearly double the time spent on a servowriter, jumping from four revolutions per data-track to seven. This is likely to be an unacceptable cost for most applications. If the same innovation is applied to a self-servowriting operation as described above, however, the relative increase in servowriting time is much smaller. Since the self-servowriting time is already nineteen revolutions per data-track, an additional three revolutions adds only about 16% to the self-servowriting time, which is much less expensive than servowriter time. If the procedure depicted in FIG. 8 is applied to a servowriter or media-writer operation, the time will be 150% greater than the standard servowriter time, taking into consideration the original four revolutions per data track plus three additional revolutions for each of the two separate erases. In the self-servowriting case, the additional six revolutions per data-track add only about 32% to the time. While such a technique may add an unacceptable cost to a servowriter or media-writer process, the process may add an acceptable cost to a self-servowriting process. FIG. 9 shows a method that can be used in accordance with one embodiment of the present invention. In this exemplary method, the writing of an A-burst/B-burst boundary is described. It should be understood that the method can be used with any set of bursts in any order. In this method, an A-burst is written on a first revolution of a disk 800 upon which a servo pattern is to be written. At least a portion of the A-burst is trimmed on a subsequent rotation of the disk 802. If the A-burst is not completely trimmed 804, step 802 can be repeated until the entire A-burst is trimmed. At least a portion of the B-burst for the given burst boundary can be written on a subsequent revolution 806. If the B-burst is not completely written 808, step 806 can be repeated until the entire B-burst is written. The writing and trimming of the burst boundary is then complete 810. It should be understood, however, that steps 802-808 can be done in any reasonable order. For example, steps 806 and 808 for writing the B-burst can occur before steps 802 and 804 for trimming the A-burst. It is also possible to intersperse the writing of the B-burst with the trimming of the A-burst, such that you could write the A-burst, write at least a portion of the B-burst, trim at least a portion of the A-burst, then write another portion of the B-burst. Although embodiments described herein refer generally to systems having a read/write head that can be used to write bursts on rotating magnetic media, similar advantages can be obtained with other such data storage systems or devices. For example, a laser writing information to an optical media can take advantage of additional passes when writing position information. Any media, or at least any rotating media, upon which information is written, placed, or stored, may be able to take advantage of embodiments of the present invention. The foregoing description of preferred embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to one of ordinary skill in the relevant arts. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalence. | <SOH> BACKGROUND <EOH>Advances in data storage technology have provided for ever-increasing storage capability in devices such as DVD-ROMs, optical drives, and disk drives. In hard disk drives, for example, the width of a written data track has decreased due in part to advances in read/write head technology, as well as in reading, writing, and positioning technologies. More narrow data tracks result in higher density drives, which is good for the consumer but creates new challenges for drive manufacturers. As the density of the data increases, the tolerance for error in the position of a drive component such as a read/write head decreases. As the position of such a head relative to a data track becomes more important, so too does the placement of information, such as servo data, that is used to determine the position of a head relative to a data track. | <SOH> BRIEF SUMMARY <EOH>Systems and methods in accordance with the present invention take advantage of multiple passes in servowriting and self-servowriting applications. These additional passes allow patterns such as servo burst pairs to be written and/or trimmed on separate passes. The additional passes reduce the written runout, as the average misplacement decreases when the number of passes increases. Each burst in a servo pattern can also be written and/or trimmed in multiple passes. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims. | 20040405 | 20070220 | 20051110 | 90424.0 | 0 | OLSON, JASON C | SYSTEMS FOR SELF-SERVOWRITING WITH MULTIPLE PASSES PER SERVOWRITING STEP | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,818,187 | ACCEPTED | Novel guanidino compounds | Compounds having the general structure III are provided: where D is N or C; W is selected from Z1, Z2, and Z3 are independently selected from CR8 and N; and the other variables have the values described herein. Compounds of formula III have useful properties for controlling diseases related to MC4-R action in humans including obesity and type II diabetes. | 1. A compound of formula III wherein X and Y are independently selected from the group consisting of CH2, N, C═O, NR9, C═S, S═O, SO2, O, S, (CR6R7)n, C(═O)—(CR6R7)n, and C(═S)—(CR6R7)n; wherein when X is CH2, then Y is not CH2; wherein when X is NH, then Y is not NH; n is selected from 1, 2, or 3; D is selected from the group consisting of N and C; L is selected from the group consisting of N, O, S, S═O, SO2, C(O), NC(O), NC(S), OC(O), OC(S), C(NR10), C(NOR10), and a covalent bond; W is selected from the group consisting of Z1, Z2, and Z3 are independently selected from the group consisting of CR8 and N; R1 is selected from the group consisting of H, and substituted and unsubstituted arylalkyl, heteroarylalkyl, aryl, heteroaryl, heterocyclyl, cycloalkyl, heterocyclylalkyl, cycloalkylalkyl, alkenyl, alkynyl, and alkyl groups; R2 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkylalkyl, aryl, and arylalkyl groups; R3 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R2 and R3 may join together to form a ring containing at least two N atoms; R4 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups; R5 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted heterocyclyl or heteroaryl group; R6 and R7 may be the same or different, and are each independently selected from the group consisting of H, Cl, I, F, Br, OH, NH2, CN, NO2, and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; R8 is independently selected from the group consisting of H, Cl, I, F, Br, OH, NH2, CN, NO2, and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; R9 and R10 are independently selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, cycloalkylalkyl, alkylcarbonyl, and arylcarbonyl groups; and prodrugs thereof, pharmaceutically acceptable salts thereof, stereoisomers thereof, tautomers thereof, hydrates thereof, or solvates thereof. 2. The compound of claim 1, wherein X and Y are independently selected from CH2, N, C═O, NR9, or (CR6R7)n. 3. The compound of claim 2, wherein X is CH2, Y is C═O, and D is N. 4. The compound of claim 2, wherein X is C═O, Y is CH2, and D is N. 5. The compound of claim 2, wherein X is N, Y is NH, D is C, and the bond between X and D is a double bond. 6. The compound of claim 2, wherein X is NH, Y is N, D is C, and the bond between Y and D is a double bond. 7. The compound of claim 2, wherein X is C═O, Y is C═O, and D is N. 8. The compound of claim 2, wherein L is a covalent bond, Z1, Z2, and Z3 are all CH, R1 is a substituted or unsubstituted arylalkyl group, W is R2 is H, R3 is a substituted or unsubstituted cycloalkyl group, and R4 and R5, together with the N to which they are bound, form a substituted or unsubstituted piperazino group. 9. The compound of claim 1, wherein L is a covalent bond. 10. The compound of claim 1, wherein Z1, Z2, and Z3 are all CH. 11. The compound of claim 1, wherein R1 is selected from substituted or unsubstituted arylalkyl, heteroarylalkyl, or heterocyclylalkyl groups. 12. The compound of claim 1, wherein R1 is a 2,4-disubstituted phenethyl group. 13. The compound of claim 1, wherein R1 is selected from 2,4-dihalophenethyl groups or 2,4-dialkylphenethyl groups. 14. The compound of claim 1, wherein R1 is selected from phenethyl, 2,4-dichlorophenethyl, 4-methoxyphenethyl, 4-bromophenethyl, 4-methylphenethyl, 4-chlorophenethyl, 4-chlorobenzyl, 4-ethylphenethyl, cyclohexenylethyl, 2-methoxyphenethyl, 2-chlorophenethyl, 2-fluorophenethyl, 3-methoxyphenethyl, 3-fluorophenethyl, thienylethyl, indolylethyl, 4-hydroxyphenethyl, or 3,4-dimethoxyphenethyl groups. 15. The compound of claim 1, wherein R2 is H. 16. The compound of claim 1, wherein R3 is selected from substituted or unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, or cycloalkylalkyl groups. 17. The compound of claim 1, wherein R3 is selected from the group consisting of substituted and unsubstituted cycloalkyl, alkenyl, alkyl, and aryl groups. 18. The compound of claim 1, wherein R3 is selected from substituted or unsubstituted cyclohexyl, 2-alkylcyclohexyl, 2,2-dialkylcyclohexyl, 2,3-dialkylcyclohexyl, 2,4-dialkylcyclohexyl, 2,5-dialkylcyclohexyl, 2,6-dialkylcyclohexyl, 3,4-dialkylcyclohexyl, 3-alkylcyclohexyl, 4-alkylcyclohexyl, 3,3,5-trialkylcyclohexyl, cyclohexylmethyl, 2-aminocyclohexyl, 3-aminocyclohexyl, 4-aminocyclohexyl, 2,3-diaminocyclohexyl, 2,4-diaminocyclohexyl, 3,4-diaminocyclohexyl, 2,5-diaminocyclohexyl, 2,6-diaminocyclohexyl, 2,2-diaminocyclohexyl, 2-alkoxycyclohexyl, 3-alkoxycyclohexyl, 4-alkoxycyclohexyl, 2,3-dialkoxycyclohexyl, 2,4-dialkoxycyclohexyl, 3,4-dialkoxycyclohexyl, 2,5-dialkoxycyclohexyl, 2,6-dialkoxycyclohexyl, 2,2-dialkoxycyclohexyl, 2-alkylthiocyclohexyl, 3-alkylthiocyclohexyl, 4-alkylthiocyclohexyl, 2,3-dialkylthiocyclohexyl, 2,4-dialkylthiocyclohexyl, 3,4-dialkylthiocyclohexyl, 2,5-dialkylthiocyclohexyl, 2,6-dialkylthiocyclohexyl, 2,2-dialkylthiocyclohexyl, cyclopentyl, cycloheptyl, cyclohexenyl, isopropyl, n-butyl, cyclooctyl, 2-arylcyclohexyl, 2-phenylcyclohexyl, 2-arylalkylcyclohexyl, 2-benzylcyclohexyl, 4-phenylcyclohexyl, adamantyl, isopinocampheyl, carenyl, 7,7-dialkylnorbornyl, bornyl, norbornyl, or decalinyl groups. 19. The compound of claim 1, wherein R3 is selected from substituted or unsubstituted cyclohexyl, 2-methylcyclohexyl, 2,2-dimethylcyclohexyl, 2,3-dimethylcyclohexyl, 2,4-dimethylcyclohexyl, 2,5-dimethylcyclohexyl, 2,6-dimethylcyclohexyl, 3,4-dimethylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, cyclohex-3-enyl, 3,3,5-trimethylcyclohexyl, 4-t-butylcyclohexyl, 2-methylcycloheptyl, cyclohexylmethyl, isopinocampheyl, 7,7-dimethyinorbornyl, 4-isopropylcyclohexyl, 2,6,6-trimethylbicyclo[3.1.1]heptyl, or 3-methylcycloheptyl groups. 20. The compound of claim 1, wherein R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted piperazino, morpholino, pyrrolidino, piperidino, homopiperazino, or azepino group. 21. The compound of claim 1, wherein R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted piperazino group. 22. The compound of claim 1, wherein R4 and R5, together with the nitrogen to which they are bound, form a piperazino group substituted by one or two methyl groups. 23. A composition comprising the compound according to claim 1 and a pharmaceutically acceptable carrier. 24. A method of treating an MC4-R mediated disease, comprising administering to a subject in need thereof, the compound according to claim 1. 25. The method according to claim 24, wherein the disease is obesity or type II diabetes. 26. A composition comprising the compound according to claim 8 and a pharmaceutically acceptable carrier. 27. A method of treating an MC4-R mediated disease, comprising administering to a subject in need thereof, the compound according to claim 8. 28. The method according to claim 27, wherein the disease is obesity or type II diabetes. | CROSS-REFERENCES TO RELATED APPLICATIONS This application is a divisional of and claims priority to U.S. Ser. No. 10/118,730, filed on Apr. 8, 2002, pending which claims priority to U.S. Provisional Application No. 60/282,847 filed Apr. 9, 2001, and now abandoned, the entire disclosures of which are incorporated herein by reference and for all purposes. FIELD OF THE INVENTION This invention relates to melanocortin-4 receptor (MC4-R) agonists and methods of their preparation. The invention also relates to methods of treating melanocortin-4 receptor-mediated diseases, such as obesity or diabetes, by activating the melanocortin-4 receptor with compounds provided herein. BACKGROUND OF THE INVENTION Melanocortins are peptide products resulting from post-translational processing of pro-opiomelanocortin and are known to have a broad array of physiological activities. The natural melanocortins include the different types of melanocyte stimulating hormone (α-MSH, β-MSH, γ-MSH) and ACTH. Of these, α-MSH and ACTH are considered to be the main endogenous melanocortins. The melanocortins mediate their effects through melanocortin receptors (MC-R), a subfamily of G-protein coupled receptors. There are at least five different receptor subtypes (MC1-R to MC5-R). MC1-R mediates pigmentation of the hair and skin. MC2-R mediates the effects of ACTH on steroidogenisis in the adrenal gland. MC3-R and MC4-R are predominantly expressed in the brain. MC5-R is considered to have a role in the exocrine gland system. The melanocortin-4 receptor (MC4-R) is a seven-transmembrane receptor. MC4-R may participate in modulating the flow of visual and sensory information, coordinate aspects of somatomotor control, and/or participate in the modulation of autonomic oufflow to the heart. Science 1992 257:1248-125. Significantly, inactivation of this receptor by gene targeting has resulted in mice that develop a maturity onset obesity syndrome associated with hyperphagia, hyperinsulinemia, and hyperglycemia. Cell 1997 Jan. 10; 88(1): 131-41. MC4-R has also been implicated in other disease states including erectile disorders, cardiovascular disorders, neuronal injuries or disorders, inflammation, fever, cognitive disorders, and sexual behavior disorders. Hadley M. E. and Haskell-Luevano C., The proopiomelanocortin system. Ann N Y Acad Sci, 1999 Oct. 20; 885:1. Furthermore, observations in connection with endogenous MCx-R antagonists indicate that MC4-R is implicated in endogenous energy regulation. For example, an agouti protein is normally expressed in the skin and is an antagonist of the cutaneous MC receptor involved in pigmentation, MC1-R. M. M. Ollmann et al., Science, 278:135-138 (1997). However, overexpression of agouti protein in mice leads to a yellow coat color due to antagonism of MC1-R and increased food intake and body weight due to antagonism of MC4-R. L. L. Kiefer et al., Biochemistry, 36: 2084-2090 (1997); D. S. Lu et al., Nature, 371:799-802 (1994). Agouti related protein (AGRP), an agouti protein homologue, antagonizes MC4-R but not MC1-R. T. M. Fong et al., Biochem. Biophys. Res. Commun. 237:629-631 (1997). Administration of AGRP in mice increases food intake and causes obesity but does not alter pigmentation. M. Rossi et al., Endocrinology, 139:4428-4431 (1998). Together, this research indicates that MC4-R participates in energy regulation, and therefore, identifies this receptor as a target for a rational drug design for the treatment of obesity. In connection with MC4-R and its uncovered role in the etiology of obesity and food intake, the prior art has reported compounds or compositions that act as agonists or antagonists of MC4-R. As examples, U.S. Pat. No. 6,060,589 describes polypeptides that are capable of modulating signaling activity of melanocortin receptors. Also, U.S. Pat. Nos. 6,054,556 and 5,731,408 describe families of agonists and antagonists for MC4-R receptors that are lactam heptapeptides having a cyclic structure. There is a need to for potent and specific agonists of MC4-R that are low molecular weight non-peptide small molecules. Methods of treating a melanocortin-4 receptor mediated disease, such as obesity, with such non-peptide drugs, are also particularly desirable. SUMMARY OF THE INVENTION The instant invention provides potent and specific agonists of MC4-R that are low molecular weight non-peptide small molecules. Thus, there has been provided, in accordance with one aspect of the invention, a compound of formula I: wherein X and Y are independently selected from the group consisting of CH2, N, NR9, C═O, C═S, S═O, SO2, S, O, (CR6R7)n, C(═O)—(CR6R7)n, and C(═S)—(CR6R7)n; n is 1, 2, or 3; W is selected from the group consisting of L is selected from the group consisting of N, O, S, S═O, SO2, C(O), NC(O), NC(S), OC(O), OC(S), C(NR10), C(NOR10), and a covalent bond; Z1, Z2, and Z3 are independently selected from the group consisting of CR8 and N; R1 is selected from the group consisting of H, and substituted and unsubstituted arylalkyl, heteroarylalkyl, aryl, heteroaryl, heterocyclyl, cycloalkyl, heterocyclylalkyl, cycloalkylalkyl, alkenyl, alkynyl, and alkyl groups; R2 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkylalkyl, aryl, and arylalkyl groups; R3 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R2 and R3 may join together to form a ring containing at least two N atoms; R4 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R2 and R4 may join together to form a ring containing at least two N atoms; R5 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted heterocyclyl or heteroaryl group, or R3 and R5 may join together to form a ring containing at least two N atoms; R6 and R7 may be the same or different, and are each independently selected from the group consisting of H, Cl, I, F, Br, OH, NH2, CN, NO2, and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; R8 is independently selected from the group consisting of H, Cl, I, F, Br, OH, NH2, CN, NO2, and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; and R9 and R10 are independently selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, cycloalkylalkyl, alkylcarbonyl, and arylcarbonyl groups. Compounds provided by the invention further include prodrugs of the compound of formula I, pharmaceutically acceptable salts thereof, stereoisomers thereof, tautomers thereof, hydrates thereof, hydrides thereof, or solvates thereof. In one embodiment, X is CH2 and Y is C═O. In another embodiment, X is C═O and Y is CH2. In another embodiment, X is C═O and Y is C═O. In other embodiments, L is a covalent bond, and X and Y have the values according to any of the previous embodiments. In another embodiment, Z1, Z2, and Z3 are all CH, and X, Y, and L have the values according to any of the previous embodiments. In another embodiment, at least one of Z1, Z2, or Z3 is N, and X, Y, and L have the values according to any of the previous embodiments. In another embodiment, X, Y, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of substituted and unsubstituted arylalkyl, alkenyl, heteroarylalkyl, and heterocyclylalkyl groups. In another embodiment, X, Y, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is 2,4-disubstituted phenethyl. In another embodiment, X, Y, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of 2,4-dihalophenethyl, and 2,4-dialkylphenethyl. In another embodiment, X, Y, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of phenethyl, 2,4-dichlorophenethyl, 4-methoxyphenethyl, 4-bromophenethyl, 4-methylphenethyl, 4-chlorophenethyl, 4-chlorobenzyl, 4-ethylphenethyl, cyclohexenylethyl, 2-methoxyphenethyl, 2-chlorophenethyl, 2-fluorophenethyl, 3-methoxyphenethyl, 3-fluorophenethyl, thienylethyl, indolylethyl, 4-hydroxyphenethyl, and 3,4-dimethoxyphenethyl. In another embodiment, X, Y, L, Z1, Z2, Z3, and R1 have any of the values of previous embodiments, and R2 is H. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cycloalkyl, alkenyl, alkyl, and aryl groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-alkylcyclohexyl, 2,2-dialkylcyclohexyl, 2,3-dialkylcyclohexyl, 2,4-dialkylcyclohexyl, 2,5-dialkylcyclohexyl, 2,6-dialkylcyclohexyl, 3,4-dialkylcyclohexyl, 3-alkylcyclohexyl, 4-alkylcyclohexyl, 3,3,5-trialkylcyclohexyl, cyclohexylmethyl, 2-aminocyclohexyl, 3-aminocyclohexyl, 4-aminocyclohexyl, 2,3-diaminocyclohexyl, 2,4-diaminocyclohexyl, 3,4-diaminocyclohexyl, 2,5-diaminocyclohexyl, 2,6-diaminocyclohexyl, 2,2-diaminocyclohexyl, 2-alkoxycyclohexyl, 3-alkoxycyclohexyl, 4-alkoxycyclohexyl, 2,3-dialkoxycyclohexyl, 2,4-dialkoxycyclohexyl, 3,4-dialkoxycyclohexyl, 2,5-dialkoxycyclohexyl, 2,6-dialkoxycyclohexyl, 2,2-dialkoxycyclohexyl, 2-alkylthiocyclohexyl, 3-alkylthiocyclohexyl, 4-alkylthiocyclohexyl, 2,3-dialkylthiocyclohexyl, 2,4-dialkylthiocyclohexyl, 3,4-dialkylthiocyclohexyl, 2,5-dialkylthiocyclohexyl, 2,6-dialkylthiocyclohexyl, 2,2-dialkylthiocyclohexyl, cyclopentyl, cycloheptyl, cyclohexenyl, isopropyl, n-butyl, cyclooctyl, 2-arylcyclohexyl, 2-phenylcyclohexyl, 2-arylalkylcyclohexyl, 2-benzylcyclohexyl, 4-phenylcyclohexyl, adamantyl, isocamphenyl, carenyl, 7,7-dialkylnorbornyl, bornyl, norbornyl, and decalinyl groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-methylcyclohexyl, 2,2-dimethylcyclohexyl, 2,3-dimethylcyclohexyl, 2,4-dimethylcyclohexyl, 2,5-dimethylcyclohexyl, 2,6-dimethylcyclohexyl, 3,4-dimethylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, cyclohex-3-enyl, 3,3,5-trimethylcyclohexyl, 4-t-butylcyclohexyl, 2-methylcycloheptyl, cyclohexylmethyl, isopinocampheyl, 7,7-dimethylnorbornyl, 4-isopropylcyclohexyl, 2,6,6-trimethylbicyclo[3.1.1]heptyl, and 3-methylcycloheptyl. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, R2, and R3 have any of the values of previous embodiments, and R5 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, R2, and R3 have any of the values of previous embodiments, R4 is H, and R5 is selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, R2, and R3 have any of the values of previous embodiments, R4 is H, and R5 is selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, R2, and R3 have any of the values of previous embodiments, and R4 and R5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, R2, and R3 have any of the values of previous embodiments, and R4 and R5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, R2, and R3 have any of the values of previous embodiments, and R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted piperazino, morpholino, pyrrolidino, piperidino, homopiperazino, or azepino group. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, R2, and R3 have any of the values of previous embodiments, and R4 and R5, together with the nitrogen to which they are bound, form a piperazino group optionally substituted by one or two alkyl groups, for example, one or two methyl groups. There has also been provided, in accordance with another aspect of the invention, a compound of formula II: wherein A is selected from the group consisting of C or CH; X and Y are independently selected from the group consisting of CH2, N, C═O, C═S, (CR6R7)n, S═O, SO2, O, NR9, S, C(═O)—(CR6R7)n, and C(═S)—(CR6R7)n; n is 1, 2, or 3; W is selected from the group consisting of Z1, Z2, and Z3 are independently selected from the group consisting of CR8 and N; L is selected from the group consisting of N, O, S, S═O, SO2, C(O), NC(O), NC(S), OC(O), OC(S), C(NR10), C(NOR10), and a covalent bond; R1 is selected from the group consisting of H, and substituted and unsubstituted arylalkyl, heteroarylalkyl, aryl, heterocyclyl, cycloalkyl, heterocyclylalkyl, cycloalkylalkyl, alkenyl, alkynyl, and alkyl groups; R2 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkylalkyl, aryl, and arylalkyl groups; R3 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R2 and R3 may join together to form a ring containing at least two N atoms; R4 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R2 and R4 may join together to form a ring containing at least two N atoms; R5 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted heterocyclyl or heteroaryl group, or R3 and R5 may join together to form a ring containing at least two N atoms; R6 and R7 may be the same or different, and are each independently selected from the group consisting of H, Cl, I, F, Br, OH, NH2, CN, NO2, and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; R8 is independently selected from the group consisting of H, Cl, I, F, Br, OH, NH2, CN, NO2, and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; and R9 and R10 are independently selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, cycloalkylalkyl, alkylcarbonyl, and arylcarbonyl groups. Compounds provided by the invention further include prodrugs of the compound of formula II, pharmaceutically acceptable salts thereof, stereoisomers thereof, tautomers thereof, hydrates thereof, hydrides thereof, or solvates thereof. In one embodiment, X is N, Y is NH, A is C, and the bond between X and A is a double bond. In another embodiment, X is NH, Y is N, A is C, and the bond between Y and A is a double bond. In another embodiment, A is C and the bond between either A and X or between A and Y is a double bond. In another embodiment, X, Y, and A have any of the values of previous embodiments, and L is a covalent bond. In another embodiment, X, Y, A, and L have any of the values of previous embodiments, and Z1, Z2, and Z3 are all CH. In another embodiment, X, Y, A, and L have any of the values of previous embodiments, and at least one of Z1, Z2, or Z3 is N. In another embodiment, X, Y, A, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of substituted and unsubstituted arylalkyl, alkenyl, heteroarylalkyl, and heterocyclylalkyl groups. In another embodiment, X, Y, A, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is 2,4-disubstituted phenethyl. In another embodiment, X, Y, A, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of 2,4-dihalophenethyl, and 2,4-dialkylphenethyl. In another embodiment, X, Y, A, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of phenethyl, 2,4-dichlorophenethyl, 4-methoxyphenethyl, 4-bromophenethyl, 4-methylphenethyl, 4-chlorophenethyl, 4-chlorobenzyl, 4-ethylphenethyl, cyclohexenylethyl, 2-methoxyphenethyl, 2-chlorophenethyl, 2-fluorophenethyl, 3-methoxyphenethyl, 3-fluorophenethyl, thienylethyl, indolylethyl, 4-hydroxyphenethyl, and 3,4-dimethoxyphenethyl. In another embodiment, X, Y, A, L, Z1, Z2, Z3, and R1 have any of the values of previous embodiments, and R2 is H. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cycloalkyl, alkenyl, alkyl, and aryl groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-alkylcyclohexyl, 2,2-dialkylcyclohexyl, 2,3-dialkylcyclohexyl, 2,4-dialkylcyclohexyl, 2,5-dialkylcyclohexyl, 2,6-dialkylcyclohexyl, 3,4-dialkylcyclohexyl, 3-alkylcyclohexyl, 4-alkylcyclohexyl, 3,3,5-trialkylcyclohexyl, cyclohexylmethyl, 2-aminocyclohexyl, 3-aminocyclohexyl, 4-aminocyclohexyl, 2,3-diaminocyclohexyl, 2,4-diaminocyclohexyl, 3,4-diaminocyclohexyl, 2,5-diaminocyclohexyl, 2,6-diaminocyclohexyl, 2,2-diaminocyclohexyl, 2-alkoxycyclohexyl, 3-alkoxycyclohexyl, 4-alkoxycyclohexyl, 2,3-dialkoxycyclohexyl, 2,4-dialkoxycyclohexyl, 3,4-dialkoxycyclohexyl, 2,5-dialkoxycyclohexyl, 2,6-dialkoxycyclohexyl, 2,2-dialkoxycyclohexyl, 2-alkylthiocyclohexyl, 3-alkylthiocyclohexyl, 4-alkylthiocyclohexyl, 2,3-dialkylthiocyclohexyl, 2,4-dialkylthiocyclohexyl, 3,4-dialkylthiocyclohexyl, 2,5-dialkylthiocyclohexyl, 2,6-dialkylthiocyclohexyl, 2,2-dialkylthiocyclohexyl, cyclopentyl, cycloheptyl, cyclohexenyl, isopropyl, n-butyl, cyclooctyl, 2-arylcyclohexyl, 2-phenylcyclohexyl, 2-arylalkylcyclohexyl, 2-benzylcyclohexyl, 4-phenylcyclohexyl, adamantyl, isocamphenyl, carenyl, 7,7-dialkylnorbornyl, bornyl, norbornyl, and decalinyl groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-methylcyclohexyl, 2,2-dimethylcyclohexyl, 2,3-dimethylcyclohexyl, 2,4-dimethylcyclohexyl, 2,5-dimethylcyclohexyl, 2,6-dimethylcyclohexyl, 3,4-dimethylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, cyclohex-3-enyl, 3,3,5-trimethylcyclohexyl, 4-t-butylcyclohexyl, 2-methylcycloheptyl, cyclohexylmethyl, isopinocampheyl, 7,7-dimethylnorbornyl, 4-isopropylcyclohexyl, 2,6,6-trimethylbicyclo[3.1.1]heptyl, and 3-methylcycloheptyl. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R5 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, R4 is H, and R5 is selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, R4 is H, and R5 is selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted piperazino, morpholino, pyrrolidino, piperidino, homopiperazino, or azepino group. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5, together with the nitrogen to which they are bound, form a piperazino group optionally substituted by one or two alkyl groups, for example, one or two methyl groups. There has also been provided, in accordance with another aspect of the invention, a compound of formula III: wherein X and Y are independently selected from the group consisting of CH2, N, C═O, NR9, C═S, S═O, SO2, O, S, (CR6R7)n, C(═O)—(CR6R7)n, and C(═S)—(CR6R7)n; D is selected from the group consisting of N, and C; If X is N, then Y is not N, but may be NH; If Y is N, then X is not N, but may be NH; If X is CH2, then Y is not CH2; If Y is CH2, then X is not CH2; If X is NH, then Y is not NH; If Y is NH, then X is not NH; L is selected from the group consisting of N, O, S, S═O, SO2, C(O), NC(O), NC(S), OC(O), OC(S), C(NR10), C(NOR10), and a covalent bond; W is selected from the group consisting of Z1, Z2, and Z3 are independently selected from the group consisting of CR8 and N; R1 is selected from the group consisting of H, and substituted and unsubstituted arylalkyl, heteroarylalkyl, aryl, heteroaryl, heterocyclyl, cycloalkyl, heterocyclylalkyl, cycloalkylalkyl, alkenyl, alkynyl, and alkyl groups; R2 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkylalkyl, aryl, and arylalkyl groups; R3 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R2 and R3 may join together to form a ring containing at least two N atoms; R4 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R2 and R4 may join together to form a ring containing at least two N atoms; R5 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted heterocyclyl or heteroaryl group, or R3 and R5 may join together to form a ring containing at least two N atoms; R6 and R7 may be the same or different, and are each independently selected from the group consisting of H, Cl, I, F, Br, OH, NH2, CN, NO2, and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkyiaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; R8 is independently selected from the group consisting of H, Cl, I, F, Br, OH, NH2, CN, NO2, and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; and R9 and R10 are independently selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, cycloalkylalkyl, alkylcarbonyl, and arylcarbonyl groups. Compounds provided by the invention further include prodrugs of the compound of formula III, pharmaceutically acceptable salts thereof, stereoisomers thereof, tautomers thereof, hydrates thereof, hydrides thereof, or solvates thereof. In one embodiment, X is CH2, Y is C═O, and D is N. In another embodiment, X is C═O, Y is CH2, and D is N. In another embodiment, X is C═O, Y is C═O, and D is N. In another embodiment, X is N, Y is NH, D is C, and the bond between X and D is a double bond. In another embodiment, X is NH, Y is N, D is C, and the bond between Y and D is a double bond. In another embodiment, X, Y, and D have any of the values of previous embodiments, and L is a covalent bond. In another embodiment, X, Y, D, and L have any of the values of previous embodiments, and Z1, Z2, and Z3 are all CH. In another embodiment, X, Y, D, and L have any of the values of previous embodiments, and at least one of Z1, Z2, or Z3 is N. In another embodiment, X, Y, D, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of substituted and unsubstituted arylalkyl, alkenyl, heteroarylalkyl, and heterocyclylalkyl groups. In another embodiment, X, Y, D, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is 2,4-disubstituted phenethyl. In another embodiment, X, Y, D, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of 2,4-dihalophenethyl, and 2,4-dialkylphenethyl. In another embodiment, X, Y, D, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of phenethyl, 2,4-dichlorophenethyl, 4-methoxyphenethyl, 4-bromophenethyl, 4-methylphenethyl, 4-chlorophenethyl, 4-chlorobenzyl, 4-ethylphenethyl, cyclohexenylethyl, 2-methoxyphenethyl, 2-chlorophenethyl, 2-fluorophenethyl, 3-methoxyphenethyl, 3-fluorophenethyl, thienylethyl, indolylethyl, 4-hydroxyphenethyl, and 3,4-dimethoxyphenethyl. In another embodiment, X, Y, D, L, Z1, Z2, Z3, and R1 have any of the values of previous embodiments, and R2 is H. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cycloalkyl, alkenyl, alkyl, and aryl groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-alkylcyclohexyl, 2,2-dialkylcyclohexyl, 2,3-dialkylcyclohexyl, 2,4-dialkylcyclohexyl, 2,5-dialkylcyclohexyl, 2,6-dialkylcyclohexyl, 3,4-dialkylcyclohexyl, 3-alkylcyclohexyl, 4-alkylcyclohexyl, 3,3,5-trialkylcyclohexyl, cyclohexylmethyl, 2-aminocyclohexyl, 3-aminocyclohexyl, 4-aminocyclohexyl, 2,3-diaminocyclohexyl, 2,4-diaminocyclohexyl, 3,4-diaminocyclohexyl, 2,5-diaminocyclohexyl, 2,6-diaminocyclohexyl, 2,2-diaminocyclohexyl, 2-alkoxycyclohexyl, 3-alkoxycyclohexyl, 4-alkoxycyclohexyl, 2,3-dialkoxycyclohexyl, 2,4-dialkoxycyclohexyl, 3,4-dialkoxycyclohexyl, 2,5-dialkoxycyclohexyl, 2,6-dialkoxycyclohexyl, 2,2-dialkoxycyclohexyl, 2-alkylthiocyclohexyl, 3-alkylthiocyclohexyl, 4-alkylthiocyclohexyl, 2,3-dialkylthiocyclohexyl, 2,4-dialkylthiocyclohexyl, 3,4-dialkylthiocyclohexyl, 2,5-dialkylthiocyclohexyl, 2,6-dialkylthiocyclohexyl, 2,2-dialkylthiocyclohexyl, cyclopentyl, cycloheptyl, cyclohexenyl, isopropyl, n-butyl, cyclooctyl, 2-arylcyclohexyl, 2-phenylcyclohexyl, 2-arylalkylcyclohexyl, 2-benzylcyclohexyl, 4-phenylcyclohexyl, adamantyl, isocamphenyl, carenyl, 7,7-dialkylnorbornyl, bornyl, norbornyl, and decalinyl groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-methylcyclohexyl, 2,2-dimethylcyclohexyl, 2,3-dimethylcyclohexyl, 2,4-dimethylcyclohexyl, 2,5-dimethylcyclohexyl, 2,6-dimethylcyclohexyl, 3,4-dimethylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, cyclohex-3-enyl, 3,3,5-trimethylcyclohexyl, 4-t-butylcyclohexyl, 2-methylcycloheptyl, cyclohexylmethyl, isopinocampheyl, 7,7-dimethylnorbornyl, 4-isopropylcyclohexyl, 2,6,6-trimethylbicyclo[3.1.1]heptyl, and 3-methylcycloheptyl. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R5 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, R4 is H, and R5 is selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, R4 is H, and R5 is selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted piperazino, morpholino, pyrrolidino, piperidino, homopiperazino, or azepino group. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5, together with the nitrogen to which they are bound, form a piperazino group optionally substituted by one or two alkyl groups, for example, one or two methyl groups. There has also been provided, in accordance with another aspect of the invention, a composition comprising a compound according to the instant invention and a pharmaceutically acceptable carrier. There has also been provided, in accordance with another aspect of the invention, a method of activating MC4-R, comprising administering to a subject in need thereof, an effective amount of a compound or composition of the instant invention. There has also been provided, in accordance with another aspect of the invention, a method of treating an MC4-R mediated disease, comprising administering to a subject in need thereof, a compound or composition of the instant invention. In one embodiment, a disease to be treated by those methods of the instant invention is obesity, or type I or type II diabetes. There has also been provided, in accordance with another aspect of the invention, a method of decreasing blood glucose levels, comprising administering to a subject in need thereof, a compound or composition of the instant invention. In various alternative embodiments, the composition is administered orally, rectally, by subcutaneous injection, by intravenous injection, by intramuscular injection, or by intraperitoneal injection. Other objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The instant invention relates to novel classes of small molecule melanocortin-4 receptor (MC4-R) agonists. These compounds can be formulated into compositions and are useful in activating MC4-R, or in the treatment of MC4-R-mediated diseases, such as obesity. The following definitions are used throughout this specification: Alkyl groups are straight chain lower alkyl groups having 1 to about 8 carbon atoms, as exemplified by methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl. Alkyl groups also include branched chain isomers of straight chain alkyl groups, including, but not limited to, isopropyl, sec-butyl, t-butyl, isopentyl and so on. Representative substituted alkyl groups may be substituted one or more times with, for example, amino, thio, alkoxy, or halo. Cycloalkyl groups are cyclic alkyl groups such as, but not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups, and can include two or more bridgehead carbon atoms to form polycyclic rings (e.g., norbornyl or bicyclo[3.1.1]heptyl). Cycloalkyl groups also includes rings that are substituted with straight or branched chain alkyl groups as defined above (e.g., bornyl or 2,6,6-trimethylbicyclo[3.1.1]heptyl). Representative substituted cycloalkyl groups may be mono-substituted or substituted more than once, such as, but not limited to, 2,2-, 2,3-, 2,4- 2,5- or 2,6-disubstituted cyclohexyl groups or mono-, di- or tri-substituted norbornyl or cycloheptyl groups, which may be substituted with, for example, alkyl, alkoxy, amino, thio, or halo groups. Alkenyl groups are straight chain, branched or cyclic lower alkyl groups having 2 to about 8 carbon atoms, and further including at least one double bond, as exemplified, for instance, by vinyl, propenyl, 2-butenyl, 3-butenyl, isobutenyl, cyclohexenyl, cyclopentenyl, cyclohexadienyl, butadienyl, pentadienyl, and hexadienyl groups among others. Alkynyl groups are straight chain or branched lower alkyl groups having 2 to about 8 carbon atoms, and further including at least one triple bond, as exemplified by groups, including, but not limited to, ethynyl, propynyl, and butynyl groups. Aryl groups are cyclic aromatic hydrocarbons that do not contain heteroatoms. Thus aryl groups include, but are not limited to, phenyl, azulene, heptalene, biphenylene, indacene, fluorene, phenanthrene, triphenylene, pyrene, naphthacene, chrysene, biphenyl, anthracenyl, and naphthenyl groups. Although the phrase “aryl groups” includes groups containing fused rings, such as fused aromatic-aliphatic ring systems, it does not include aryl groups that have other groups, such as alkyl or halo groups, bonded to one of the ring members. Rather, groups such as tolyl are referred to as substituted aryl groups. The phrase “aryl groups” includes groups bonded to one or more carbon atom(s), and/or nitrogen atom(s), in the compounds of formulas I and II. Representative substituted aryl groups may be mono-substituted or substituted more than once, such as, but not limited to, 2-, 3-, 4-, 5-, or 6-substituted phenyl or benzyl groups, which may be substituted with groups including, but not limited to, amino, alkoxy, alkyl, or halo. Cycloalkylalkyl groups are alkyl groups as defined above in which a hydrogen or carbon bond of an alkyl group is replaced with a bond to a cycloalkyl group as defined above. Arylalkyl groups are alkyl groups as defined above in which a hydrogen or carbon bond of an alkyl group is replaced with a bond to an aryl group as defined above. Heterocyclyl groups are nonaromatic ring compounds containing 3 or more ring members, of which, one or more is a heteroatom such as, but not limited to, N, O, and S. The phrase “heterocyclyl group” includes fused ring species including those comprising fused aromatic and nonaromatic groups. However, the phrase does not include heterocyclyl groups that have other groups, such as alkyl or halo groups, bonded to one of the ring members. Rather, these are referred to as “substituted heterocyclyl groups”. Heterocyclyl groups include, but are not limited to, piperazino, morpholino, thiomorpholino, pyrrolidino, piperidino and homopiperazino groups. Representative substituted heterocyclyl groups may be mono-substituted or substituted more than once, such as, but not limited to morphilino or piperazino groups, which are 2-, 3-, 4-, 5-, or 6-substituted, or disubstituted with groups including, but not limited to, amino, alkoxy, alkyl, or halo. Heteroaryl groups are aromatic ring compounds containing 3 or more ring members, of which, one or more is a heteroatom such as, but not limited to, N, O, and S. Heteroaryl groups include, but are not limited to, groups such as furan, thiophene, pyrrole, isopyrrole, diazole, imidazole, isoimidazole, triazole, dithiole, oxathiole, isoxazole, oxazole, thiazole, isothiazole, oxadiazole, oxatriazole, dioxazole, oxathiazole, pyran, dioxin, pyridine, pyrimidine, pyridazine, pyrazine, triazine, oxazine, isoxazine, oxathiazine, azepin, oxepin, thiepin, diazepine, benzofuran, and isobenzofuran. Although the phrase “heteroaryl groups” includes fused ring compounds, the phrase does not include heteroaryl groups that have other groups bonded to one of the ring members, such as alkyl groups. Rather, heteroaryl groups with such substitution are referred to as “substituted heterocyclyl groups”. Representative substituted heterocyclyl groups may be substituted one or more times with groups including, but not limited to, amino, alkoxy, alkyl, or halo. Heterocyclylalkyl groups are alkyl groups as defined above in which a hydrogen or carbon bond of an alkyl group is replaced with a bond to a heterocyclyl group as defined above. Heteroarylalkyl groups are alkyl groups as defined above in which a hydrogen or carbon bond of an alkyl group is replaced with a bond to a heteroaryl group as defined above. Aminocarbonyl groups are groups of the formula RR′NC(O)—, wherein R or R′ may be the same or different, and each is independently selected from H, or substituted or unsubstituted alkyl, cycloalkyl, aryl, heterocyclyl or heteroaryl groups, as defined above. In general, “substituted” refers to a group as defined above in which one or more bonds to a hydrogen atom contained therein are replaced by a bond to non-hydrogen or non-carbon atoms such as, but not limited to, a halogen atom such as F, Cl, Br, and I; an oxygen atom in groups such as hydroxyl groups, alkoxy groups, aryloxy groups, and ester groups; a sulfur atom in groups such as thiol groups, alkyl and aryl sulfide groups, sulfone groups, sulfonyl groups, and sulfoxide groups; a nitrogen atom in groups such as amines, amides, alkylamines, dialkylamines, arylamines, alkylarylamines, diarylamines, N-oxides, imides, and enamines; a silicon atom in groups such as in trialkylsilyl groups, dialkylarylsilyl groups, alkyldiarylsilyl groups, and triarylsilyl groups; and other heteroatoms in various other groups. Substituted alkyl groups and also substituted cycloalkyl groups also include groups in which one or more bonds to a carbon(s) or hydrogen(s) atom is replaced by a bond to a heteroatom such as oxygen in carbonyl, carboxyl, and ester groups; nitrogen in groups such as imines, oximes, hydrazones, and nitriles. Substituted cycloalkyl, substituted aryl, substituted heterocyclyl and substituted heteroaryl also include rings and fused ring systems which may be substituted with alkyl groups as defined above. Substituted arylalkyl groups may be substituted on the aryl group, on the alkyl group, or on both the aryl and alkyl groups. The instant invention provides potent and specific agonists of MC4-R that are low molecular weight non-peptide small molecules. Thus, there has been provided, in accordance with one aspect of the invention, a compound of formula I: wherein X and Y are independently selected from the group consisting of CH2, N, NR9, C═O, C═S, S═O, SO2, S, O, (CR6R7)n, C(═O)—(CR6R7)n, and C(═S)—(CR6R7)n; n is 1, 2, or 3; W is selected from the group consisting of L is selected from the group consisting of N, O, S, S═O, SO2, C(O), NC(O), NC(S), OC(O), OC(S), C(NR10), C(NOR10), and a covalent bond; Z1, Z2, and Z3 are independently selected from the group consisting of CR8 and N; R1 is selected from the group consisting of H, and substituted and unsubstituted arylalkyl, heteroarylalkyl, aryl, heteroaryl, heterocyclyl, cycloalkyl, heterocyclylalkyl, cycloalkylalkyl, alkenyl, alkynyl, and alkyl groups; R2 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkylalkyl, aryl, and arylalkyl groups; R3 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R2 and R3 may join together to form a ring containing at least two N atoms; R4 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R2 and R4 may join together to form a ring containing at least two N atoms; R5 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted heterocyclyl or heteroaryl group, or R3 and R5 may join together to form a ring containing at least two N atoms; R6 and R7 may be the same or different, and are each independently selected from the group consisting of H, Cl, I, F, Br, OH, NH2, CN, NO2, and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; R8 is independently selected from the group consisting of H, Cl, I, F, Br, OH, NH2, CN, NO2, and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; and R9 and R10 are independently selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, cycloalkylalkyl, alkylcarbonyl, and arylcarbonyl groups. Compounds provided by the invention further include prodrugs of the compound of formula I, pharmaceutically acceptable salts thereof, stereoisomers thereof, tautomers thereof, hydrates thereof, hydrides thereof, or solvates thereof. In one embodiment, X is CH2 and Y is C═O. In another embodiment, X is C═O and Y is CH2. In another embodiment, X is C═O and Y is C═O. In other embodiments, L is a covalent bond, and X and Y have the values according to any of the previous embodiments. In another embodiment, Z1, Z2, and Z3 are all CH, and X, Y, and L have the values according to any of the previous embodiments. In another embodiment, at least one of Z1, Z2, or Z3 is N, and X, Y, and L have the values according to any of the previous embodiments. In another embodiment, X, Y, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of substituted and unsubstituted arylalkyl, alkenyl, heteroarylalkyl, and heterocyclylalkyl groups. In another embodiment, X, Y, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is 2,4-disubstituted phenethyl. In another embodiment, X, Y, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of 2,4-dihalophenethyl, and 2,4-dialkylphenethyl. In another embodiment, X, Y, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of phenethyl, 2,4-dichlorophenethyl, 4-methoxyphenethyl, 4-bromophenethyl, 4-methylphenethyl, 4-chlorophenethyl, 4-chlorobenzyl, 4-ethylphenethyl, cyclohexenylethyl, 2-methoxyphenethyl, 2-chlorophenethyl, 2-fluorophenethyl, 3-methoxyphenethyl, 3-fluorophenethyl, thienylethyl, indolylethyl, 4-hydroxyphenethyl, and 3,4-dimethoxyphenethyl. In another embodiment, X, Y, L, Z1, Z2, Z3, and R1 have any of the values of previous embodiments, and R2 is H. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cycloalkyl, alkenyl, alkyl, and aryl groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-alkylcyclohexyl, 2,2-dialkylcyclohexyl, 2,3-dialkylcyclohexyl, 2,4-dialkylcyclohexyl, 2,5-dialkylcyclohexyl, 2,6-dialkylcyclohexyl, 3,4-dialkylcyclohexyl, 3-alkylcyclohexyl, 4-alkylcyclohexyl, 3,3,5-trialkylcyclohexyl, cyclohexylmethyl, 2-aminocyclohexyl, 3-aminocyclohexyl, 4-aminocyclohexyl, 2,3-diaminocyclohexyl, 2,4-diaminocyclohexyl, 3,4-diaminocyclohexyl, 2,5-diaminocyclohexyl, 2,6-diaminocyclohexyl, 2,2-diaminocyclohexyl, 2-alkoxycyclohexyl, 3-alkoxycyclohexyl, 4-alkoxycyclohexyl, 2,3-dialkoxycyclohexyl, 2,4-dialkoxycyclohexyl, 3,4-dialkoxycyclohexyl, 2,5-dialkoxycyclohexyl, 2,6-dialkoxycyclohexyl, 2,2-dialkoxycyclohexyl, 2-alkylthiocyclohexyl, 3-alkylthiocyclohexyl, 4-alkylthiocyclohexyl, 2,3-dialkylthiocyclohexyl, 2,4-dialkylthiocyclohexyl, 3,4-dialkylthiocyclohexyl, 2,5-dialkylthiocyclohexyl, 2,6-dialkylthiocyclohexyl, 2,2-dialkylthiocyclohexyl, cyclopentyl, cycloheptyl, cyclohexenyl, isopropyl, n-butyl, cyclooctyl, 2-arylcyclohexyl, 2-phenylcyclohexyl, 2-arylalkylcyclohexyl, 2-benzylcyclohexyl, 4-phenylcyclohexyl, adamantyl, isocamphenyl, carenyl, 7,7-dialkylnorbornyl, bornyl, norbornyl, and decalinyl groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-methylcyclohexyl, 2,2-dimethylcyclohexyl, 2,3-dimethylcyclohexyl, 2,4-dimethylcyclohexyl, 2,5-dimethylcyclohexyl, 2,6-dimethylcyclohexyl, 3,4-dimethylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, cyclohex-3-enyl, 3,3,5-trimethylcyclohexyl, 4-t-butylcyclohexyl, 2-methylcycloheptyl, cyclohexylmethyl, isopinocampheyl, 7,7-dimethylnorbornyl, 4-isopropylcyclohexyl, 2,6,6-trimethylbicyclo[3.1.1]heptyl, and 3-methylcycloheptyl. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, R2, and R3 have any of the values of previous embodiments, and R5 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, R2, and R3 have any of the values of previous embodiments, R4 is H, and R5 is selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, R2, and R3 have any of the values of previous embodiments, R4 is H, and R5 is selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, R2, and R3 have any of the values of previous embodiments, and R4 and R5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, R2, and R3 have any of the values of previous embodiments, and R4 and R5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, R2, and R3 have any of the values of previous embodiments, and R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted piperazino, morpholino, pyrrolidino, piperidino, homopiperazino, or azepino group. In another embodiment, X, Y, L, Z1, Z2, Z3, R1, R2, and R3 have any of the values of previous embodiments, and R4 and R5, together with the nitrogen to which they are bound, form a piperazino group optionally substituted by one or two alkyl groups, for example, one or two methyl groups. There has also been provided, in accordance with another aspect of the invention, a compound of formula II: wherein A is selected from the group consisting of C or CH; X and Y are independently selected from the group consisting of CH2, N, C═O, C═S, (CR6R7)n, S═O, SO2, O, NR9, S, C(═O)—(CR6R7)n, and C(═S)—(CR6R7)n; n is 1, 2, or 3; W is selected from the group consisting of Z1, Z2, and Z3 are independently selected from the group consisting of CR8 and N; L is selected from the group consisting of N, O, S, S═O, SO2, C(O), NC(O), NC(S), OC(O), OC(S), C(NR10), C(NOR10), and a covalent bond; R1 is selected from the group consisting of H, and substituted and unsubstituted arylalkyl, heteroarylalkyl, aryl, heterocyclyl, cycloalkyl, heterocyclylalkyl, cycloalkylalkyl, alkenyl, alkynyl, and alkyl groups; R2 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkylalkyl, aryl, and arylalkyl groups; R3 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R2 and R3 may join together to form a ring containing at least two N atoms; R4 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R2 and R4 may join together to form a ring containing at least two N atoms; R5 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted heterocyclyl or heteroaryl group, or R3 and R5 may join together to form a ring containing at least two N atoms; R6 and R7 may be the same or different, and are each independently selected from the group consisting of H, Cl, I, F, Br, OH, NH2, CN, NO2, and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; R8 is independently selected from the group consisting of H, Cl, I, F, Br, OH, NH2, CN, NO2, and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups and R9 and R10 are independently selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, cycloalkylalkyl, alkylcarbonyl, and arylcarbonyl groups. Compounds provided by the invention further include prodrugs of the compound of formula II, pharmaceutically acceptable salts thereof, stereoisomers thereof, tautomers thereof, hydrates thereof, hydrides thereof, or solvates thereof. In one embodiment, X is N, Y is NH, A is C, and the bond between X and A is a double bond. In another embodiment, X is NH, Y is N, A is C, and the bond between Y and A is a double bond. In another embodiment, A is C and the bond between either A and X or between A and Y is a double bond. In another embodiment, X, Y, and A have any of the values of previous embodiments, and L is a covalent bond. In another embodiment, X, Y, A, and L have any of the values of previous embodiments, and Z1, Z2, and Z3 are all CH. In another embodiment, X, Y, A, and L have any of the values of previous embodiments, and at least one of Z1, Z2, or Z3 is N. In another embodiment, X, Y, A, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of substituted and unsubstituted arylalkyl, alkenyl, heteroarylalkyl, and heterocyclylalkyl groups. In another embodiment, X, Y, A, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is 2,4-disubstituted phenethyl. In another embodiment, X, Y, A, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of 2,4-dihalophenethyl, and 2,4-dialkylphenethyl. In another embodiment, X, Y, A, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of phenethyl, 2,4-dichlorophenethyl, 4-methoxyphenethyl, 4-bromophenethyl, 4-methylphenethyl, 4-chlorophenethyl, 4-chlorobenzyl, 4-ethylphenethyl, cyclohexenylethyl, 2-methoxyphenethyl, 2-chlorophenethyl, 2-fluorophenethyl, 3-methoxyphenethyl, 3-fluorophenethyl, thienylethyl, indolylethyl, 4-hydroxyphenethyl, and 3,4-dimethoxyphenethyl. In another embodiment, X, Y, A, L, Z1, Z2, Z3, and R1 have any of the values of previous embodiments, and R2 is H. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cycloalkyl, alkenyl, alkyl, and aryl groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-alkylcyclohexyl, 2,2-dialkylcyclohexyl, 2,3-dialkylcyclohexyl, 2,4-dialkylcyclohexyl, 2,5-dialkylcyclohexyl, 2,6-dialkylcyclohexyl, 3,4-dialkylcyclohexyl, 3-alkylcyclohexyl, 4-alkylcyclohexyl, 3,3,5-trialkylcyclohexyl, cyclohexylmethyl, 2-aminocyclohexyl, 3-aminocyclohexyl, 4-aminocyclohexyl, 2,3-diaminocyclohexyl, 2,4-diaminocyclohexyl, 3,4-diaminocyclohexyl, 2,5-diaminocyclohexyl, 2,6-diaminocyclohexyl, 2,2-diaminocyclohexyl, 2-alkoxycyclohexyl, 3-alkoxycyclohexyl, 4-alkoxycyclohexyl, 2,3-dialkoxycyclohexyl, 2,4-dialkoxycyclohexyl, 3,4-dialkoxycyclohexyl, 2,5-dialkoxycyclohexyl, 2,6-dialkoxycyclohexyl, 2,2-dialkoxycyclohexyl, 2-alkylthiocyclohexyl, 3-alkylthiocyclohexyl, 4-alkylthiocyclohexyl, 2,3-dialkylthiocyclohexyl, 2,4-dialkylthiocyclohexyl, 3,4-dialkylthiocyclohexyl, 2,5-dialkylthiocyclohexyl, 2,6-dialkylthiocyclohexyl, 2,2-dialkylthiocyclohexyl, cyclopentyl, cycloheptyl, cyclohexenyl, isopropyl, n-butyl, cyclooctyl, 2-arylcyclohexyl, 2-phenylcyclohexyl, 2-arylalkylcyclohexyl, 2-benzylcyclohexyl, 4-phenylcyclohexyl, adamantyl, isocamphenyl, carenyl, 7,7-dialkylnorbornyl, bornyl, norbornyl, and decalinyl groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-methylcyclohexyl, 2,2-dimethylcyclohexyl, 2,3-dimethylcyclohexyl, 2,4-dimethylcyclohexyl, 2,5-dimethylcyclohexyl, 2,6-dimethylcyclohexyl, 3,4-dimethylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, cyclohex-3-enyl, 3,3,5-trimethylcyclohexyl, 4-t-butylcyclohexyl, 2-methylcycloheptyl, cyclohexylmethyl, isopinocampheyl, 7,7-dimethylnorbornyl, 4-isopropylcyclohexyl, 2,6,6-trimethylbicyclo[3.1.1]heptyl, and 3-methylcycloheptyl. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R5 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, R4 is H, and R5 is selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, R4 is H, and R5 is selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted piperazino, morpholino, pyrrolidino, piperidino, homopiperazino, or azepino group. In another embodiment, X, Y, A, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5, together with the nitrogen to which they are bound, form a piperazino group optionally substituted by one or two alkyl groups, for example, one or two methyl groups. There has also been provided, in accordance with another aspect of the invention, a compound of formula III: wherein X and Y are independently selected from the group consisting of CH2, N, C═O, NR9, C═S, S═O, SO2, O, S, (CR6R7)n, C(═O)—(CR6R7)n, and C(═S)—(CR6R7)n; D is selected from the group consisting of N, and C; If X is N, then Y is not N, but may be NH; If Y is N, then X is not N, but may be NH; If X is CH2, then Y is not CH2; If Y is CH2, then X is not CH2; If X is NH, then Y is not NH; If Y is NH, then X is not NH; L is selected from the group consisting of N, O, S, S═O, SO2, C(O), NC(O), NC(S), OC(O), OC(S), C(NR10), C(NOR10), and a covalent bond; W is selected from the group consisting of Z1, Z2, and Z3 are independently selected from the group consisting of CR8 and N; R1 is selected from the group consisting of H, and substituted and unsubstituted arylalkyl, heteroarylalkyl, aryl, heteroaryl, heterocyclyl, cycloalkyl, heterocyclylalkyl, cycloalkylalkyl, alkenyl, alkynyl, and alkyl groups; R2 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkylalkyl, aryl, and arylalkyl groups; R3 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R2 and R3 may join together to form a ring containing at least two N atoms; R4 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R2 and R4 may join together to form a ring containing at least two N atoms; R5 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted heterocyclyl or heteroaryl group, or R3 and R5 may join together to form a ring containing at least two N atoms; R6 and R7 may be the same or different, and are each independently selected from the group consisting of H, Cl, I, F, Br, OH, NH2, CN, NO2, and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; R8 is independently selected from the group consisting of H, Cl, I, F, Br, OH, NH2, CN, NO2, and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; and R9 and R10 are independently selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, cycloalkylalkyl, alkylcarbonyl, and arylcarbonyl groups. Compounds provided by the invention further include prodrugs of the compound of formula III, pharmaceutically acceptable salts thereof, stereoisomers thereof, tautomers thereof, hydrates thereof, hydrides thereof, or solvates thereof. In one embodiment, X is CH2, Y is C═O, and D is N. In another embodiment, X is C═O, Y is CH2, and D is N. In another embodiment, X is C═O, Y is C═O, and D is N. In another embodiment, X is N, Y is NH, D is C, and the bond between X and D is a double bond. In another embodiment, X is NH, Y is N, D is C, and the bond between Y and D is a double bond. In another embodiment, X, Y, and D have any of the values of previous embodiments, and L is a covalent bond. In another embodiment, X, Y, D, and L have any of the values of previous embodiments, and Z1, Z2, and Z3 are all CH. In another embodiment, X, Y, D, and L have any of the values of previous embodiments, and at least one of Z1, Z2, or Z3 is N. In another embodiment, X, Y, D, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of substituted and unsubstituted arylalkyl, alkenyl, heteroarylalkyl, and heterocyclylalkyl groups. In another embodiment, X, Y, D, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is 2,4-disubstituted phenethyl. In another embodiment, X, Y, D, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of 2,4-dihalophenethyl, and 2,4-dialkylphenethyl. In another embodiment, X, Y, D, L, Z1, Z2, and Z3 have any of the values of previous embodiments, and R1 is selected from the group consisting of phenethyl, 2,4-dichlorophenethyl, 4-methoxyphenethyl, 4-bromophenethyl, 4-methylphenethyl, 4-chlorophenethyl, 4-chlorobenzyl, 4-ethylphenethyl, cyclohexenylethyl, 2-methoxyphenethyl, 2-chlorophenethyl, 2-fluorophenethyl, 3-methoxyphenethyl, 3-fluorophenethyl, thienylethyl, indolylethyl, 4-hydroxyphenethyl, and 3,4-dimethoxyphenethyl. In another embodiment, X, Y, D, L, Z1, Z2, Z3, and R1 have any of the values of previous embodiments, and R2 is H. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cycloalkyl, alkenyl, alkyl, and aryl groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-alkylcyclohexyl, 2,2-dialkylcyclohexyl, 2,3-dialkylcyclohexyl, 2,4-dialkylcyclohexyl, 2,5-dialkylcyclohexyl, 2,6-dialkylcyclohexyl, 3,4-dialkylcyclohexyl, 3-alkylcyclohexyl, 4-alkylcyclohexyl, 3,3,5-trialkylcyclohexyl, cyclohexylmethyl, 2-aminocyclohexyl, 3-aminocyclohexyl, 4-aminocyclohexyl, 2,3-diaminocyclohexyl, 2,4-diaminocyclohexyl, 3,4-diaminocyclohexyl, 2,5-diaminocyclohexyl, 2,6-diaminocyclohexyl, 2,2-diaminocyclohexyl, 2-alkoxycyclohexyl, 3-alkoxycyclohexyl, 4-alkoxycyclohexyl, 2,3-dialkoxycyclohexyl, 2,4-dialkoxycyclohexyl, 3,4-dialkoxycyclohexyl, 2,5-dialkoxycyclohexyl, 2,6-dialkoxycyclohexyl, 2,2-dialkoxycyclohexyl, 2-alkylthiocyclohexyl, 3-alkylthiocyclohexyl, 4-alkylthiocyclohexyl, 2,3-dialkylthiocyclohexyl, 2,4-dialkylthiocyclohexyl, 3,4-dialkylthiocyclohexyl, 2,5-dialkylthiocyclohexyl, 2,6-dialkylthiocyclohexyl, 2,2-dialkylthiocyclohexyl, cyclopentyl, cycloheptyl, cyclohexenyl, isopropyl, n-butyl, cyclooctyl, 2-arylcyclohexyl, 2-phenylcyclohexyl, 2-arylalkylcyclohexyl, 2-benzylcyclohexyl, 4-phenylcyclohexyl, adamantyl, isocamphenyl, carenyl, 7,7-dialkylnorbornyl, bornyl, norbornyl, and decalinyl groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, and R2 have any of the values of previous embodiments, and R3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-methylcyclohexyl, 2,2-dimethylcyclohexyl, 2,3-dimethylcyclohexyl, 2,4-dimethylcyclohexyl, 2,5-dimethylcyclohexyl, 2,6-dimethylcyclohexyl, 3,4-dimethylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, cyclohex-3-enyl, 3,3,5-trimethylcyclohexyl, 4-t-butylcyclohexyl, 2-methylcycloheptyl, cyclohexylmethyl, isopinocampheyl, 7,7-dimethylnorbornyl, 4-isopropylcyclohexyl, 2,6,6-trimethylbicyclo[3.1.1]heptyl, and 3-methylcycloheptyl. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R5 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, R4 is H, and R5 is selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, R4 is H, and R5 is selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5, together with the nitrogen to which they are bound, form a substituted or unsubstituted piperazino, morpholino, pyrrolidino, piperidino, homopiperazino, or azepino group. In another embodiment, X, Y, D, L, Z1, Z2, Z3, R1, R2 and R3 have any of the values of previous embodiments, and R4 and R5 together with the nitrogen to which they are bound, form a piperazino group optionally substituted by one or two alkyl groups, for example, one or two methyl groups. There has also been provided, in accordance with another aspect of the invention, a composition comprising a compound according to the instant invention and a pharmaceutically acceptable carrier. There has also been provided, in accordance with another aspect of the invention, a method of activating MC4-R, comprising administering to a subject in need thereof, an effective amount of a compound or composition of the instant invention. There has also been provided, in accordance with another aspect of the invention, a method of treating an MC4-R mediated disease, comprising administering to a subject in need thereof, a compound or composition of the instant invention. In one embodiment, a disease to be treated by those methods of the instant invention is obesity, or type I or type II diabetes. There has also been provided, in accordance with another aspect of the invention, a method of decreasing blood glucose levels, comprising administering to a subject in need thereof, a compound or composition of the instant invention. In various alternative embodiments, the composition is administered orally, rectally, by subcutaneous injection, by intravenous injection, by intramuscular injection, or by intraperitoneal injection. The variables “(CR6R7)n”, “C(═O)—(CR6R7)n”, and “C(═S)—(CR6R7)n” are used with respect to X and Y in compounds of formula I, II, and III where n has the value of 1, 2, or 3. The variable “(CR6R7)n” has the same meaning in compounds of formula I, II, and III. The same is true with respect to the variables “C(═O)—(CR6R7)n” and “C(═S)—(CR6R7)n”. Compounds of formula I will be used to illustrate what these variables mean. In compounds of formula I as shown below X and Y are independently selected from the group consisting of CH2, N, NH, C═O, C═S, S═O, SO2, O, (CR6R7)n, C(═O)—(CR6R7)n, and C(═S)—(CR6R7)n; and n is 1, 2, or 3 as described above. The variable “(CR6R7)n” indicates that X and/or Y may be a one, two, or three carbon chain with the carbons bearing the R6 and R7 groups. Thus, if X is a three carbon chain (n=3) and Y is a one carbon chain, the ring bearing the X, Y and N will contain 7 members. It should be noted that where n=3 and X or Y is a “(CR6R7)n” group, the three carbon chain may be substituted where each carbon bears the same R6 and R7 substituents although this is not required. For example, X could be a —CH2CH(Cl)C(Cl)2— group because R6 and R7 may be H and Cl. Thus, the nomenclature used herein is not meant to restrict each of the carbons to bearing exactly the same substituents as would be the case for n=3 for an X group such as —CH(Cl)—CH(Cl)—CH(Cl)—. This same feature is true with respect to the variables “C(═O)—(CR6R7)n” and “C(═S)—(CR6R7)n”. With respect to the variables “C(═O)—(CR6R7)n” and “C(═S)—(CR6R7)n”, X and/or Y may contain from two to four carbon atoms since n=1, 2, or 3, and the C═O and C═S groups of these species contains one carbon atoms. With respect to the variables “C(═O)—(CR6R7)n” and “C(═S)—(CR6R7)n”, either terminus of the group may be bonded to the N atom in the ring containing the X, Y, and N. Thus, the carbonyl carbon of the C(═O)—(CR6R7)n group may be the carbon directly bonded to the N in the ring, but one of the CR6R7 carbons may alternatively be bonded to the ring N atom. Preferably, however, it is the C═O and C═S carbons of such groups that is bonded to the ring N atoms. As described above, in some embodiments L may be a covalent bond. In embodiments where L is a covalent bond, the R1 group is directly bonded to the N in the ring containing the X and Y in compounds of formula I or is directly bonded to A or D in the ring containing the X and Y in compounds of formulas II and III respectively. Pharmaceutically acceptable salts include a salt with an inorganic base, organic base, inorganic acid, organic acid, or basic or acidic amino acid. As salts of inorganic bases, the invention includes, for example, alkali metals such as sodium or potassium, alkali earth metals such as calcium and magnesium or aluminum, and ammonia. As salts of organic bases, the invention includes, for example, trimethylamine, triethylamine, pyridine, picoline, ethanolamine, diethanolamine, triethanolamine. As salts of inorganic acids, the instant invention includes, for example, hydrochloric acid, hydroboric acid, nitric acid, sulfuric acid, and phosphoric acid. As salts of organic acids, the instant invention includes, for example, formic acid, acetic acid, trifluoroacetic acid, fumaric acid, oxalic acid, tartaric acid, maleic acid, citric acid, succinic acid, malic acid, methanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid. As salts of basic amino acids, the instant invention includes, for example, arginine, lysine and ornithine. Acidic amino acids include, for example, aspartic acid and glutamic acid. Prodrugs, as used in the context of the instant invention, includes those derivatives of the instant compounds which undergo in vivo metabolic biotransformation, by enzymatic or nonenzymatic processes, such as hydrolysis, to form a compound of the invention. Prodrugs can be employed to improve pharmaceutical or biological properties, as for example solubility, melting point, stability and related physicochemical properties, absorption, pharmacodynamics and other delivery-related properties. The invention also includes tautomers of the instant compounds. For example, the instant invention also includes all tautomers of formula I, II, and III. The instant invention also, therefore, includes prodrugs, pharmaceutically acceptable salts, stereoisomers, hydrates, hydrides, or solvates of these tautomers. The instant compounds may exist as one or more stereoisomers. The various stereoisomers include enantiomers, diastereomers, atropisomers and geometric isomers. In some cases, one stereoisomer may be more active and/or may exhibit beneficial effects in comparison to other stereoisomer(s) or when separated from the other stereoisomer(s). However, it is well within the skill of the ordinary artisan to separate, and/or to selectively prepare said stereoisomers. Accordingly, “stereoisomers” of the instant invention necessarily includes mixtures of stereoisomers, individual stereoisomers, or optically active forms. The instant invention also provides for compositions which may be prepared by mixing one or more compounds of the instant invention, or pharmaceutically acceptable salts or tautomers thereof, with pharmaceutically acceptable carriers, excipients, binders, diluents or the like, to treat or ameliorate a variety of disorders. Examples of such disorders include, but are not limited to obesity, erectile disorders, cardiovascular disorders, neuronal injuries or disorders, inflammation, fever, cognitive disorders, sexual behavior disorders. A therapeutically effective dose further refers to that amount of one or more compounds of the instant invention sufficient to result in amelioration of symptoms of the disorder. The pharmaceutical compositions of the instant invention can be manufactured by methods well known in the art such as conventional granulating, mixing, dissolving, encapsulating, lyophilizing, emulsifying or levigating processes, among others. The compositions can be in the form of, for example, granules, powders, tablets, capsules, syrup, suppositories, injections, emulsions, elixirs, suspensions or solutions. The instant compositions can be formulated for various routes of administration, for example, by oral administration, by transmucosal administration, by rectal administration, or subcutaneous administration as well as intrathecal, intravenous, intramuscular, intraperitoneal, intranasal, intraocular or intraventricular injection. The compound or compounds of the instant invention can also be administered in a local rather than a systemic fashion, such as injection as a sustained release formulation. The following dosage forms are given by way of example and should not be construed as limiting the instant invention. For oral, buccal, and sublingual administration, powders, suspensions, granules, tablets, pills, capsules, gelcaps, and caplets are acceptable as solid dosage forms. These can be prepared, for example, by mixing one or more compounds of the instant invention, or pharmaceutically acceptable salts or tautomers thereof, with at least one additive or excipient such as a starch or other additive. Suitable additives or excipients are sucrose, lactose, cellulose sugar, mannitol, maltitol, dextran, sorbitol, starch, agar, alginates, chitins, chitosans, pectins, tragacanth gum, gum arabic, gelatins, collagens, casein, albumin, synthetic or semi-synthetic polymers or glycerides, methyl cellulose, hydroxypropylmethyl-cellulose, and/or polyvinylpyrrolidone. Optionally, oral dosage forms can contain other ingredients to aid in administration, such as an inactive diluent, or lubricants such as magnesium stearate, or preservatives such as paraben or sorbic acid, or anti-oxidants such as ascorbic acid, tocopherol or cysteine, a disintegrating agent, binders, a thickeners, buffers, a sweeteners, flavoring agents or perfuming agents. Additionally, dyestuffs or pigments may be added for identification. Tablets and pills may be further treated with suitable coating materials known in the art. Liquid dosage forms for oral administration may be in the form of pharmaceutically acceptable emulsions, syrups, elixirs, suspensions, slurries and solutions, which may contain an inactive diluent, such as water. Pharmaceutical formulations may be prepared as liquid suspensions or solutions using a sterile liquid, such as, but not limited to, an oil, water, an alcohol, and combinations of these. Pharmaceutically suitable surfactants, suspending agents, emulsifying agents, may be added for oral or parenteral administration. As noted above, suspensions may include oils. Such oils include, but are not limited to, peanut oil, sesame oil, cottonseed oil, corn oil and olive oil. Suspension preparation may also contain esters of fatty acids such as ethyl oleate, isopropyl myristate, fatty acid glycerides and acetylated fatty acid glycerides. Suspension formulations may include alcohols, such as, but not limited to, ethanol, isopropyl alcohol, hexadecyl alcohol, glycerol and propylene glycol. Ethers, such as but not limited to, poly(ethyleneglycol), petroleum hydrocarbons such as mineral oil and petrolatum; and water may also be used in suspension formulations. For nasal administration, the pharmaceutical formulations may be a spray or aerosol containing and appropriate solvents and optionally other compounds such as, but not limited to, stabilizers, antimicrobial agents, antioxidants, pH modifiers, surfactants, bioavailability modifiers and combinations of these. A propellant for an aerosol formulation may include compressed air, nitrogen, carbon dioxide, or a hydrocarbon based low boiling solvent. The compound or compounds of the instant invention are conveniently delivered in the form of an aerosol spray presentation from a nebulizer or the like. Injectable dosage forms generally include aqueous suspensions or oil suspensions which may be prepared using a suitable dispersant or wetting agent and a suspending agent. Injectable forms may be in solution phase or in the form of a suspension, which is prepared with a solvent or diluent. Acceptable solvents or vehicles include sterilized water, Ringer's solution, or an isotonic aqueous saline solution. Alternatively, sterile oils may be employed as solvents or suspending agents. Preferably, the oil or fatty acid is non-volatile, including natural or synthetic oils, fatty acids, mono-, di- or tri-glycerides. For injection, the pharmaceutical formulation may be a powder suitable for reconstitution with an appropriate solution as described above. Examples of these include, but are not limited to, freeze dried, rotary dried or spray dried powders, amorphous powders, granules, precipitates, or particulates. For injection, the formulations may optionally contain stabilizers, pH modifiers, surfactants, bioavailability modifiers and combinations of these. The compounds may be formulated for parenteral administration by injection such as by bolus injection or continuous infusion. A unit dosage form for injection may be in ampoules or in multi-dose containers. For rectal administration, the pharmaceutical formulations may be in the form of a suppository, an ointment, an enema, a tablet or a cream for release of compound in the intestines, sigmoid flexure and/or rectum. Rectal suppositories are prepared by mixing one or more compounds of the instant invention, or pharmaceutically acceptable salts or tautomers of the compound, with acceptable vehicles, for example, cocoa butter or polyethylene glycol, which is present in a solid phase at normal storing temperatures, and present in a liquid phase at those temperatures suitable to release a drug inside the body, such as in the rectum. Oils may also be employed in the preparation of formulations of the soft gelatin type and suppositories. Water, saline, aqueous dextrose and related sugar solutions, and glycerols may be employed in the preparation of suspension formulations which may also contain suspending agents such as pectins, carbomers, methyl cellulose, hydroxypropyl cellulose or carboxymethyl cellulose, as well as buffers and preservatives. Besides those representative dosage forms described above, pharmaceutically acceptable excipients and carriers are generally known to those skilled in the art and are thus included in the instant invention. Such excipients and carriers are described, for example, in “Remingtons Pharmaceutical Sciences” Mack Pub. Co., New Jersey (1991), which is incorporated herein by reference. The formulations of the invention may be designed for to be short-acting, fast-releasing, long-acting, and sustained-releasing as described below. Thus, the pharmaceutical formulations may also be formulated for controlled release or for slow release. The instant compositions may also comprise, for example, micelles or liposomes, or some other encapsulated form, or may be administered in an extended release form to provide a prolonged storage and/or delivery effect. Therefore, the pharmaceutical formulations may be compressed into pellets or cylinders and implanted intramuscularly or subcutaneously as depot injections or as implants such as stents. Such implants may employ known inert materials such as silicones and biodegradable polymers. A therapeutically effective dose refers to that amount of the compound that results in amelioration of symptoms. Specific dosages may be adjusted depending on conditions of disease, the age, body weight, general health conditions, sex, diet of the subject, dose intervals, administration routes, excretion rate, and combinations of drugs. Any of the above dosage forms containing effective amounts are well within the bounds of routine experimentation and therefore, well within the scope of the instant invention. A therapeutically effective dose may vary depending upon the route of administration and dosage form. The preferred compound or compounds of the instant invention is a formulation that exhibits a high therapeutic index. The therapeutic index is the dose ratio between toxic and therapeutic effects which can be expressed as the ratio between LD50 and ED50. The LD50 is the dose lethal to 50% of the population and the ED50 is the dose therapeutically effective in 50% of the population. The LD50 and ED50 are determined by standard pharmaceutical procedures in animal cell cultures or experimental animals. The present invention also provides methods of enhancing MC4-R activity in a human or non-human animal. The method comprises administering an effective amount of a compound, or composition, of the instant invention to said mammal or non-human animal. Effective amounts of the compounds of the instant invention include those amounts that activate MC4-R which are detectable, for example, by an assay described below in the illustrative Examples, or any other assay known by those skilled in the art that a detect signal transduction, in a biochemical pathway, through activation of G-protein coupled receptors, for example, by measuring an elevated cAMP level as compared to a control model. Accordingly, “activating” means the ability of a compound to initiate a detectable signal. Effective amounts may also include those amounts which alleviate symptoms of a MC4-R disorder treatable by activating MC4-R. An MC4-R disorder, or MC4-R-mediated disease, which may be treated by those methods provided, include any biological disorder or disease in which MC4-R is implicated, or which inhibition of MC4-R potentiates a biochemical pathway that is defective in the disorder or disease state. Examples of such diseases are obesity, erectile disorders, cardiovascular disorders, neuronal injuries or disorders, inflammation, fever, cognitive disorders, and sexual behavior disorders. In a preferred embodiment, the instant invention provides compounds, compositions, and methods effective for reducing energy intake and body weight; reducing serum insulin and glucose levels; alleviating insulin resistance; and reducing serum levels of free fatty acids. Accordingly, the instant invention is particularly effective in treating those disorders or diseases associated with obesity or type II diabetes. “Treating” within the context of the instant invention, therefore, means an alleviation of symptoms associated with a disorder or disease, or halt of further progression or worsening of those symptoms, or prevention or prophylaxis of the disease or disorder. For example, within the context of obesity, successful treatment may include an alleviation of symptoms or halting the progression of the disease, as measured by reduction in body weight, or a reduction in amount of food or energy intake. In this same vein, successful treatment of type I or type II diabetes may include an alleviation of symptoms or halting the progression of the disease, as measured by a decrease in serum glucose or insulin levels in, for example, hyperinsulinemic or hyperglycemic patients. Compound Preparation Many of the described specific synthetic transformation steps are familiar to those skilled in the art and their procedures are either described or referenced in common texts such as in March Advanced Organic Chemistry 3rd ed. (Wiley, 1985), Carey and Sundberg Advanced Organic Chemistry A and B 3rd ed. (Plenum Press, 1990), and Vogel's Textbook of Practical Organic Chemistry 5th ed. (Longman, 1989). Implicit in the synthetic transformations are various techniques for purification such as silica gel chromatography, crystallizations, and distillations. These steps may be necessary for isolating the desired product, regioisomer, enantiomer, or diastereomer from a reaction product mixture. Multistep syntheses may also involve the use of protecting groups to address issues of chemo and regioselectivity that cannot otherwise be satisfactorily resolved with respect to chemical purity or yield. The use of protecting groups in organic synthesis is well known with respect to various groups such as hydroxyl groups, amine groups, and sulfhydryl groups. These and other functionalities may be protected from undesirable reactions with various protecting groups known to those skilled in the art such as those set forth in Protective Groups in Organic Synthesis, Greene, T. W., John Wiley & Sons, New York, N.Y., (1st Edition, 1981) which can be added or removed using the procedures set forth therein. Examples of protected hydroxyl groups include, but are not limited to, silyl ethers such as those obtained by reaction of a hydroxyl group with a reagent such as, but not limited to, t-butyldimethyl-chlorosilane, trimethylchlorosilane, triisopropylchlorosilane, triethylchlorosilane; substituted methyl and ethyl ethers such as, but not limited to methoxymethyl ether, methythiomethyl ether, benzyloxymethyl ether, t-butoxymethyl ether, 2-methoxyethoxymethyl ether, tetrahydropyranyl ethers, 1-ethoxyethyl ether, allyl ether, benzyl ether; esters such as, but not limited to, benzoylformate, formate, acetate, trichloroacetate, and trifluoracetate. Examples of protected amine groups include, but are not limited to, amides such as, formamide, acetamide, trifluoroacetamide, and benzamide; imides, such as phthalimide, and dithiosuccinimide; and others. Examples of protected sulfhydryl groups include, but are not limited to, thioethers such as S-benzyl thioether, and S-4-picolyl thioether; substituted S-methyl derivatives such as hemithio, dithio and aminothio acetals; and others. FIG. 1 illustrates a general synthetic route for compounds containing the following core structure: In the first part of the synthesis the non-guanidino linked portion of the bicyclic core is functionalized. In one embodiment of the method of the invention, the condensation of an amine and an anhydride gives an N-substituted phthalimide. Alternatively, if a phthalimide is used as the starting material, the phthalimide nitrogen may be functionalized by displacement of an activated alcohol. These transformations allow access to a wide range of N-substituted intermediates by varying the type of R1OH or R1NH2 inputs. It can further be appreciated that use of the appropriate starting materials for the bicyclic core can also provide, for example, compounds of the invention containing a nitrogen atom in the aromatic ring to which the guanidino moiety is attached. In the next phase of the synthetic route, the functionalized imide may be reduced to the lactam via a two step process. After separation of the desired lactam regioisomer, the primary amine may be activated by treatment with thiophosgene to form the thioisocyanate. Sequential coupling of two amines yields the desired lactam products, which can exist in two tautomeric forms. One skilled in the art would recognize that alternative couplings of amines to thioureas exist, such as the use of a myriad of carbodiimide based coupling reagents or alkylation of the sulfur atom with an alkyl halide prior to addition of an amine. Use of the other regioisomer obtained from the reduction step would lead to the regioisomeric lactam and its tautomer shown in FIG. 2 below. Furthermore, the reduction steps in FIG. 1 can be omitted in its entirety and the reaction scheme can be carried through to give the guanidino imide and its tautomer shown in FIG. 3 as products. Conversely, both carbonyl groups can be fully reduced to give the tetrahydro analogs. Additional structural variations within the non-guanidino linked portion of the bicyclic core itself can be achieved by starting with, for example, bicyclic lactams or bicyclic cyloamido compounds. These scaffolds can be generally be functionalized by methods known in the art such as N-alkylation with a variety of electrophiles (see R. Larock, Comprehensive Organic Transformations; VHC Publisher's Inc., 1989). Bicyclic lactams can also be generally functionalized as shown in FIG. 4. An amine or its activated equivalent (for example an alkyl aluminum amide) is first coupled with a lactone. The resulting product is then used in a subsequent cyclodehydration reaction (for example a Mitsunobu reaction) to give the functionalized bicyclic core. The guanidino moiety may then be installed as described above. FIG. 5 illustrates a general synthetic route for compounds of the invention containing the benzimidazole core structure. An activated acid is first condensed with a diaminonitrophenyl starting material followed by exposure of the resulting product to acidic conditions to provide the benzimidazole core. The nitro moiety is then reduced and converted to the functionalized quanidino substituent as described above. In another embodiment of the invention, benzoxazole and benzthiazole comprise the bicyclic core. These compounds may be constructed as shown in FIG. 6. Commercially available (Aldrich) 6-nitrobenzothiazole may be treated with base and quenched with N-chlorosuccinimide to give the halogenated intermediate. This compound may then be used in a number of metal mediated coupling reactions (for example Heck, Stille, Sonogashira coupling reactions) to functionalize the bicyclic core. The nitro group then serves as the attachment point for the guanidino unit. The present invention, thus generally described, will be understood more readily by reference to the following examples, which are provided by way of illustration and are not intended to be limiting of the present invention. EXAMPLES Compounds were named using the ACD/Name v. 4.53. The following abbreviations are used throughout the Examples: eq equivalent DIAD diisopropylazodicarboxylate DIBAL-H diisobutlyaluminum hydride EDC 1-ethyl-3-(3′-dimethylaminopropyl)-carbodiimide hydrochloride EtOAc ethylacetate THF tetrahydrofuran TFA trifluoroacetic acid Analytical Methodology HPLC System: HPLC was run on a Waters 2690 HPLC system. column=Reliasil 50×4.6 mm (5 μm pore size) method: (note: all solvents include 0.1% TFA) time flow rate (minutes) (mL/min) % water % CAN init. 2 95 5 15 2 20 80 15.5 2 0 100 17.5 2 0 100 18.5 2 95 5 Model HPLC=(Waters 2690 Separations Module) detector=(Waters 996 photodiode array detector) LCMS were run on HP Series 1100 LCMS system HP LCMS (1100 series) HP MSD (1100 series) time flow rate (minutes) (mL/min) % A* % B* 0 0.8 95 5 .2 0.8 95 5 3.7 0.8 5 95 3.85 0.8 95 5 5 0.8 95 5 *solvent A = (water + 0.05% TFA) and solvent B = (Acetonitrile + 0.05% TFA) column temp = 30° C. column=(brand=Eclipse XDB) 50×2 mm (5 μm) (C18) MS Methodology MWT: 150-800 CV: 20 Ionization: ESP+ i. Data: Centroid Repeat: 1 Scan Time: 2 seconds Example 1 Preparation of (3S)-N-{2-[2-(2,4-dichlorophenyl)ethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Step 1. Preparation of 2-[2-(2,4-dichlorophenyl)ethyl]-5-nitro-1H-isoindole-1,3(2H)-dione 2-(2,4-dichlorophenyl)ethanamine was suspended in toluene with 4-nitrophthalic anhydride (1 eq) and heated to 150° C. After 2 hours, the reaction was cooled and checked for completion by LC/MS. The solvent was then removed in vacuo and the resulting product was taken on to the next step without further purification. Rt 3.36 minutes (HP LCMS), LC/MS m/z 365.1 (MH+). Step 2. Preparation of 5-amino-2-[2-(2,4-dichlorophenyl)ethyl]-1H-isoindole-1,3(2H) -dione The product of the previous step was taken up in ethanol (or methanol) and purged with dry nitrogen. To this solution was introduced activated Pd/C (10% w/w, 0.1 eq) and the mixture was hydrogenated for about 30 minutes or until complete by LC/MS. The mixture was then filtered through celite, concentrated in vacuo, and taken on to the next step. Rt 2.95 minutes (HP LCMS), LC/MS m/z 335.0 (MH+). Step 3. Preparation of 5-amino-2-[2-(2,4-dichlorophenyl)ethyl]-3-hydroxyisoindolin-1-one To a CH2Cl2 solution of the phthalimide was added dropwise DIBAL-H (3 eq, 1.0 M solution in CH2Cl2) at room temperature with good stirring. After stirring for one hour, the reaction was diluted with ether, NaF (12 eq), and distilled water (9 eq) and stirred for an additional hour. The reaction mixture was then filtered through celite to remove the aluminum precipitants. After washing the celite with additional CH2Cl2, the filtrate was then concentrated in vacuo to give a crude product (mixture of regioisomers) was then used in the following step without further purification. Rt 2.09 minutes (HP LCMS) and 2.23 minutes (HP LCMS), LC/MS m/z 337.2 (MH+). Step 4. Preparation of 5-amino-2-[2-(2,4-dichlorophenyl)ethyl]isoindolin-1-one To a CH2Cl2 (0.1 M solution) of the crude product from the previous step was added dropwise triflouroacetic acid (6.0 eq) followed immediately by dropwise addition of triethylsilane (2.9 eq). After stirring for an additional 15 minutes, the mixture was concentrated in vacuo. The crude product of two regioisomeric lactams was then dissolved in acetonitrile and purified via reverse phase (C18) prep HPLC. The fractions for the desired regioisomeric lactam product (later retention time) were collected, frozen, and lyophilized. Rt 7.24minutes, LC/MS m/z 321.1 (MH+). Step 5. Preparation of 2-[2-(2,4-dichlorophenyl)ethyl]-5-isothiocyanato-isoindolin-1-one To a 0.5 M solution of the amine in acetone (0° C. ice bath) was added thiophosgene (3 eq) dropwise. After 30 minutes, the reaction mixture was allowed to warm to room temperature. After two hours, the reaction mixture was concentrated in vacuo to remove solvent and excess thiophosgene. The crude isothiocyanate product was then used in the next step without further purification. Rt 3.43 minutes (HP LCMS), LC/MS m/z 363.1 (MH+). Step 6. Preparation of N-{2-[2-(2,4-dichlorophenyl)ethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]thiourea To a solution of the crude isothiocyanate in dry acetonitrile (0.5 M solution) was added (+)-isopinocampheyl amine (1.5 eq). After stirring overnight, the reaction mixture was concentrated in vacuo and the thiourea product was dissolved in CH2Cl2 and purified via flash chromatography (1:1Hexanes:EtOAc). Fractions containing the thiourea product were concentrated in vacuo and dried to yield a creamish white colored solid. Rt 14.53 minutes, LC/MS m/z 516.4 (MH+). Step 7. Preparation of (3S)-N-{2-[2-(2,4-dichlorophenyl)ethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide To a solution of the thiourea in THF (dry, 0.5 M) in a dry vial was added (S)-(+)-2-methylpiperazine (3 eq) and EDC (3 eq). The vial was capped tightly and heated to 80° C. for approximately 2 hours. The mixture was then allowed to cool to room temperature and concentrated in vacuo. The reaction mixture was dissolved in DMSO along with TFA (1 eq) and purified by prep HPLC. The pure fractions were collected, frozen, and dried via lyopholization to give the product as a white solid. Rt 8.36 minutes, LC/MS m/z 582.5 (MH+). Example 2 Preparation of (3S)-N-{2-[2-(2,4-dichlorophenyl)ethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Step 1. Preparation of 2-[2-(2,4-dichlorophenyl)ethyl]-5-nitro-1H-isoindole-1,3(2H) -dione 2-(2,4-dichlorophenyl)ethanamine was suspended in toluene with 4-nitrophthalic anhydride (1 eq) and heated to 150° C. After 2 hours, the reaction was cooled and checked for completion by LC/MS. The solvent was then removed in vacuo and the resulting product was taken on to the next step without further purification. Rt 3.91 minutes, LC/MS m/z 365.1 (MH+). Step 2. Preparation of 5-amino-2-[2-(2,4-dichlorophenyl)ethyl]-1H-isoindole-1,3(2H) -dione The product of the previous step was taken up in ethanol (or methanol) and purged with dry nitrogen. To this solution was introduced activated Pd/C (10% w/w, 0.1 eq) and the mixture was hydrogenated for about 30 minutes or until complete by LC/MS. The mixture was then filtered through celite, concentrated in vacuo, and taken on to the next step. Rt 2.96 minutes (HP LCMS), LC/MS m/z 335.1 (MH+). Step 3. Preparation of 2-[2-(2,4-dichlorophenyl)ethyl]-5-isothiocyanatoiso-1H-isoindole-1,3(2H)dione To a 0.5 M solution of the amine in acetone (0° C. ice bath) was added thiophosgene (3 eq) dropwise. After 30 minutes, the reaction mixture was allowed to warm to room temperature. After two hours, the reaction mixture was concentrated in vacuo to remove solvent and excess thiophosgene. The crude isothiocyanate product was then used in the next step without further purification. Rt 3.75 minutes (HP LCMS), LC/MS m/z 377.0 (MH+). Step 4. Preparation of N-{2-[2-(2,4-dichlorophenyl)ethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]thiourea To a solution of the crude isothiocyanate in dry acetonitrile (0.5 M solution) was added (+)-isopinocampheyl amine (1.5 eq). After stirring overnight, the reaction mixture was concentrated in vacuo and the thiourea product was dissolved in CH2Cl2 and purified via flash chromatography (1:1Hexanes:EtOAc). Fractions containing the thiourea product were concentrated in vacuo and dried overnight via lyophilization to yield a yellowish-brown solid. Rt 3.98 minutes (HP LCMS), LC/MS m/z 596.1 (MH+). Step 5. Preparation of (3S)-N-{2-[2-(2,4-dichlorophenyl)ethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide To a solution of the thiourea in THF (dry, 0.5 M) in a dry vial was added (S)-(+)-2-methylpiperazine (3 eq) and EDC (3 eq). The vial was capped tightly and heated to 80° C. for approximately 2 hours. The mixture was then allowed to cool to room temperature and concentrated in vacuo. The reaction mixture was dissolved in DMSO along with TFA (1 eq) and purified by prep HPLC. The pure fractions were collected, frozen, and dried via lyopholization to give the product as a white solid. Rt 9.57 minutes, LC/MS m/z 596.3 (MH+). Examples 3-16 were prepared using the procedures described for 1 and 2. Example 3 (3S)-N-{2-[2-(2,4-dichlorophenyl)ethyl]-3-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from 2-(2,4-dichlorophenyl)ethanamine. Rt 8.72 minutes, LC/MS m/z 582.5 (MH+). Example 4 (3S)-N-[2-(2,4-dichlorobenzyl)-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl]-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from 1-(2,4-dichlorophenyl)methanamine. Rt 8.72 minutes, LC/MS m/z 582.5 (MH+). Example 5 (3S)-N-{2-[(1S)-1-benzyl-2-hydroxyethyl]-1,3-dioxo-2,3-dihydro-1-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from L-phenylalaninol. Rt 7.56 minutes, LC/MS m/z 558.7 (MH+). Example 6 (3S)-N-{2-[(1R)-1-benzyl-2-hydroxyethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from D-phenylalaninol. Rt 7.52 minutes, LC/MS m/z 558.7 (M H+). Example 7 (3S)-N-{2-[2-(2-fluoro-4-methylphenyl)ethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from 2-(3-fluoro-5-methylphenyl)ethanamine. Rt 7.8 minutes, LC/MS m/z 546.2 (MH+). Example 8 (3S)-N-{2-[(1S)-1-(2,4-dichlorobenzyl)-2-hydroxyethyl]-1,3-dioxo-2,3dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from L-2,4-dichlorophenylalaninol, obtained in one step from the reduction of L-2,4-dichlorophenylalanine (see, for example, JOC 2000, 65, 5037-5042). Rt 8.46 minutes, LC/MS m/z 626.2 (MH+). Example 9 (3S)-N-{2-[(1S)-1-(2,4-dichlorobenzyl)-2-hydroxyethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from L-2,4-dichlorophenylalaninol, obtained in one step from the reduction of L-2,4-dichlorophenylalanine (see, for example, JOC 2000, 65, 5037-5042). Rt 7.71 minutes, LC/MS m/z 612.2 (MH+). Example 10 (3S)-N-{2-[2-(2-fluoro-4-methoxyphenyl)ethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from 2-(2-fluoro-4-methoxyphenyl)ethanamine. Rt 8.4 minutes, LC/MS m/z 576.2 (MH+). Example 11 (3S)-N-{2-[2-(2,4-difluorophenyl)ethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from 2-(2,4-difluorophenyl)ethanamine. Rt 8.53 minutes, LC/MS m/z 564.2 (MH+). Example 12 (3S)-N-{2-[2-(2,4-dimethoxyphenyl)ethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from 2-(2,4-dimethoxyphenyl)ethanamine. Rt 8.51 minutes, LC/MS m/z 588.3 (MH+). Example 13 (3S)-N-{2-[2-(2,4-dimethylphenyl)ethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from 2-(2,4-dimethylphenyl)ethanamine. Rt 9.43 minutes, LC/MS m/z 556.2 (MH+). Example 14 (3S)-N-{2-[(1S,2S)-2-hydroxy-1-(hydroxymethyl)-2-phenylethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from (1S,2S)-(+)-2-amino-1-phenyl-1,3-propanediol. Rt 6.68 minutes, LC/MS m/z 574.3 (MH+). Example 15 (3S)-N-{2-[(1R,2R)-2-hydroxy-1-(hydroxymethyl)-2-phenylethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from (1R,2R)-(−)-2-amino-1-phenyl-1,3-propanediol. Rt 6.64 minutes, LC/MS m/z 574.3 (MH+). Example 16 (3S)-N-{2-[(1S,2R)-2-hydroxy-1-(hydroxymethyl)-2-phenylethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from (1R,2S)-(+)-2-amino-1-phenyl-1,3-propanediol. Rt 6.63 minutes, LC/MS m/z 574.3 (MH+). Example 17 (3S)-N-{2-[2-(2-fluoro-4-methoxyphenyl)ethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from 2-(2-fluoro-4-methoxyphenyl)ethanamine. Rt 7.42 minutes, LC/MS m/z 562 (MH+). Example 18 (3S)-N-{2-[2-(2,4-difluorophenyl)ethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from 2-(2,4-difluorophenyl)ethanamine. Rt 7.5 minutes, LC/MS m/z 550 (MH+). Example 19 (3S)-N-{2-[2-(2,4-difluorophenyl)ethyl]-3-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from 2-(2,4-difluorophenyl)ethanamine. Rt 7.82 minutes, LC/MS m/z 550 (MH+). Example 20 (3S)-N-{2-[2-(2,4-dimethylphenyl)ethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from 2-(2,4-dimethylphenyl)ethanamine. Rt 8.21 minutes, LC/MS m/z 542.1 (MH+). Example 21 (3S)-N-{2-[2-(2,4-dimethylphenyl)ethyl]-3-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from 2-(2,4-dimethylphenyl)ethanamine. Rt 8.5 minutes, LC/MS m/z 542.1 (MH+). Example 22 (3S)-N-{2-[2-(2,4-dichlorophenyl)ethyl]-1-oxo-1,2,3,4-tetrahydroisoquinolin-6-yl}-3-methyl-N′-[(1S,2S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide 6-nitroisochroman-1-one was treated with the dimethylaluminum amide prepared from 2-(2,4-dichlorophenyl)ethanamine, and the product obtained was cyclized using Mitsunobu conditions (as in Ian. Bell et al, Tetrahedron. Lett. (2000),41, 1141-1145). The nitro group was then reduced, and the amine was converted to the substituted guanidine (as in steps 2-5 of Example 2 above) to give the title compound. Rt 9.06 minutes, LC/MS m/z 596.1 (MH+). Example 23 (3S)-N-{2-[2-(2,4-dichlorophenyl)ethyl]-1H-benzimidazol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide 2,4-dichlorophenyl propionic acid (1.0 eq) was mixed with 4-nitro-1,2-phenylenediamine (1.1 eq) and EDC (1.5 eq) in THF at room temperature for 8 hours. The solution was diluted with ethyl acetate and washed with water (3×). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. The product was then subjected to refluxing glacial acetic acid for 30 minutes. After removal of the acetic acid in vacuo, the residue was free-based with sodium carbonate. The resulting compound was then subjected to the hydrogenation and guanidino functionalization conditions described in Example 2 above (steps 2, 3, 4, and 5) to give the desired product. Rt 7.08 minutes, LC/MS m/z 567.2 (MH+). Examples 24 and 25 can be prepared using the procedures described for Example 23. Example 24 (3S)-N-{2-[2-(2,4-dimethylphenyl)ethyl]-1H-benzimidazol-6-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from 3-(2,4-dimethylphenyl)propanoic acid. Rt 6.93 minutes, LC/MS m/z 527.3 (MH+). Example 25 (3S)-N-{2-[2-(2-chloro-4-fluorophenyl)ethyl]-1H-benzimidazol-6-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide Synthesized from 3-(2-chloro-4-fluorophenyl)propanoic acid. Rt 6.54 minutes, LC/MS m/z 551.4 (MH+). In addition to the synthesis described above, many of the synthetic transformations presented in U.S. Provisional Application No. 60/245,579 are relevant to the synthesis of the compounds of the present invention. Thus, U.S. Provisional Application No. 60/245,579, filed Nov. 6, 2000 is hereby incorporated by reference in its entirety. In Vitro Data EC50 values of test compounds were determined by treating cells expressing MC4-R with test compound and lysing the cells and measuring intercellular cAMP concentration with an Amersham-Pharmacia RPA-559 cAMP Scintillation Proximity Assay (SPA) kit. The following compounds were synthesized and tested according to this assay. The following compounds are merely illustrative and should not be construed as limiting of the instant invention. Compounds having an in vitro potency (as measured by EC50 value) of less than 3 μM include: (3S)-N-{2-[2-(2,4-dichlorophenyl)ethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2,4-dichlorophenyl)ethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2,4-dichlorophenyl)ethyl]-3-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-[2-(2,4-dichlorobenzyl)-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl]-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[(1S)-1-benzyl-2-hydroxyethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[(1R)-1-benzyl-2-hydroxyethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2-fluoro-4-methylphenyl)ethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[(1S)-1-(2,4-dichlorobenzyl)-2-hydroxyethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2-fluoro-4-methoxyphenyl)ethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2,4-difluorophenyl)ethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2,4-dimethoxyphenyl)ethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2,4-dimethylphenyl)ethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[(1S,2S)-2-hydroxy-1-(hydroxymethyl)-2-phenylethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[(1R,2R)-2-hydroxy-1-(hydroxymethyl)-2-phenylethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[(1S,2R)-2-hydroxy-1-(hydroxymethyl)-2-phenylethyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2-fluoro-4-methoxyphenyl)ethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2,4-difluorophenyl)ethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2,4-difluorophenyl)ethyl]-3-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2,4-dimethylphenyl)ethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2,4-dimethylphenyl)ethyl]-3-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2,4-dichlorophenyl)ethyl]-1H-benzimidazol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2,4-dimethylphenyl)ethyl]-1H-benzimidazol-6-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[2-(2,4-dichlorophenyl)ethyl]-1-oxo-1,2,3,4-tetrahydroisoquinolin-6-yl}-3-methyl-N′-[(1S,2S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide; (3S)-N-{2-[(1S)-1-(2,4-dichlorobenzyl)-2-hydroxyethyl]-1-oxo-2,3-dihydro-1H-isoindol-5-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]-1-piperazinecarboximidamide; and (3S)-N-{2-[2-(2-chloro-4-fluorophenyl)ethyl]-1H-benzimidazol-6-yl}-3-methyl-N′-[(1S,2S,3S,5R)-2,6,6-trimethylbicyclo[3.1.1]hept-3-yl]piperazine-1-carboximidamide. In Vivo Studies of MC4-R Agonists on Energy Intake, Body Weight, Hyperinsulinemia, and Glucose Levels In vivo studies are conducted to observe the effect of MCR-4 agonists on energy intake, body weight, hyperinsulinemia, and glucose levels. All studies are conducted with male 9-10 week old ob/ob mice which display early onset of obesity, insulin resistance and diabetes due to leptin deficiency. Mice are acclimated in the facility for 1 week before studies and are caged individually. Vehicle-treated (control) and drug treated mice studies are always run in parallel. In multi-day studies, mice (8-15 per group) are monitored for baseline body weight, fasting levels of glucose, insulin, blood lipids and energy expenditure and then are injected twice daily (9 a.m. arid 5 p.m.) with 3 mg/kg of an MC4-R agonist according to the invention for 2-4 weeks. Body weight as well as food and water intake are monitored daily. Animals are fasted overnight for measurements of fasting levels of glucose, insulin, and lipids once a week until the end of the study. Energy expenditure (resting metabolic rate, i.e., O2 consumption and CO2 production) are monitored in air tight chambers at the end of the study on fed animals. O2 consumption and CO2 production are measured using Oxymax systems (Columbus Instruments). Oral glucose tolerance test (OGTT—a routine test for diabetes and glucose intolerance) is performed on overnight fasted mice at the end of the study. Blood glucose and oral glucose tolerance are measured using a glucose monitor (Onetouch sold by Lifescan). Free fatty acids are measured using an nonesterfifed free fatty acids enzymatic assay (Waco Chemicals). Serum Insulin levels are measured by immunoassay (Alpco). The results of the above studies show that a significant reduction in food intake occurs in those mice treated IP with the compounds of the present invention. The results also show that mice treated with the compounds of the present invention show a significant body weight reduction compared to mice not treated with the compounds of the present invention. Vehicle treated mice show an increase in blood glucose consistent with the rapid progression of diabetes in this mouse strain, whereas the onset of diabetes is slowed down in mice treated with the compounds of the present invention. Oral glucose tolerance tests are performed. Orally administered glucose quickly elevates blood glucose similar to after eating a meal. Vehicle treated mice show an elevated response to glucose consistent with their diabetic state, whereas mice treated with the compounds of the present invention show a very much improved glucose disposal. Mice are fasted overnight and free fatty acid levels are measured the following morning. Vehicle treated mice show elevated free fatty acid levels consistent with their obese state, whereas mice treated with the compounds of the present invention show a dramatic 50% decrease. Serum insulin levels are measured one hour after single IP dosing of compounds of the present invention in overnight fasted ob/ob mice. Mice treated with the compounds of the present invention show a dose dependent decrease relative to vehicle. | <SOH> BACKGROUND OF THE INVENTION <EOH>Melanocortins are peptide products resulting from post-translational processing of pro-opiomelanocortin and are known to have a broad array of physiological activities. The natural melanocortins include the different types of melanocyte stimulating hormone (α-MSH, β-MSH, γ-MSH) and ACTH. Of these, α-MSH and ACTH are considered to be the main endogenous melanocortins. The melanocortins mediate their effects through melanocortin receptors (MC-R), a subfamily of G-protein coupled receptors. There are at least five different receptor subtypes (MC1-R to MC5-R). MC1-R mediates pigmentation of the hair and skin. MC2-R mediates the effects of ACTH on steroidogenisis in the adrenal gland. MC3-R and MC4-R are predominantly expressed in the brain. MC5-R is considered to have a role in the exocrine gland system. The melanocortin-4 receptor (MC4-R) is a seven-transmembrane receptor. MC4-R may participate in modulating the flow of visual and sensory information, coordinate aspects of somatomotor control, and/or participate in the modulation of autonomic oufflow to the heart. Science 1992 257:1248-125. Significantly, inactivation of this receptor by gene targeting has resulted in mice that develop a maturity onset obesity syndrome associated with hyperphagia, hyperinsulinemia, and hyperglycemia. Cell 1997 Jan. 10; 88(1): 131-41. MC4-R has also been implicated in other disease states including erectile disorders, cardiovascular disorders, neuronal injuries or disorders, inflammation, fever, cognitive disorders, and sexual behavior disorders. Hadley M. E. and Haskell-Luevano C., The proopiomelanocortin system. Ann N Y Acad Sci , 1999 Oct. 20; 885:1. Furthermore, observations in connection with endogenous MCx-R antagonists indicate that MC4-R is implicated in endogenous energy regulation. For example, an agouti protein is normally expressed in the skin and is an antagonist of the cutaneous MC receptor involved in pigmentation, MC1-R. M. M. Ollmann et al., Science , 278:135-138 (1997). However, overexpression of agouti protein in mice leads to a yellow coat color due to antagonism of MC1-R and increased food intake and body weight due to antagonism of MC4-R. L. L. Kiefer et al., Biochemistry , 36: 2084-2090 (1997); D. S. Lu et al., Nature , 371:799-802 (1994). Agouti related protein (AGRP), an agouti protein homologue, antagonizes MC4-R but not MC1-R. T. M. Fong et al., Biochem. Biophys. Res. Commun . 237:629-631 (1997). Administration of AGRP in mice increases food intake and causes obesity but does not alter pigmentation. M. Rossi et al., Endocrinology , 139:4428-4431 (1998). Together, this research indicates that MC4-R participates in energy regulation, and therefore, identifies this receptor as a target for a rational drug design for the treatment of obesity. In connection with MC4-R and its uncovered role in the etiology of obesity and food intake, the prior art has reported compounds or compositions that act as agonists or antagonists of MC4-R. As examples, U.S. Pat. No. 6,060,589 describes polypeptides that are capable of modulating signaling activity of melanocortin receptors. Also, U.S. Pat. Nos. 6,054,556 and 5,731,408 describe families of agonists and antagonists for MC4-R receptors that are lactam heptapeptides having a cyclic structure. There is a need to for potent and specific agonists of MC4-R that are low molecular weight non-peptide small molecules. Methods of treating a melanocortin-4 receptor mediated disease, such as obesity, with such non-peptide drugs, are also particularly desirable. | <SOH> SUMMARY OF THE INVENTION <EOH>The instant invention provides potent and specific agonists of MC4-R that are low molecular weight non-peptide small molecules. Thus, there has been provided, in accordance with one aspect of the invention, a compound of formula I: wherein X and Y are independently selected from the group consisting of CH 2 , N, NR 9 , C═O, C═S, S═O, SO 2 , S, O, (CR 6 R 7 ) n , C(═O)—(CR 6 R 7 ) n , and C(═S)—(CR 6 R 7 ) n ; n is 1, 2, or 3; W is selected from the group consisting of L is selected from the group consisting of N, O, S, S═O, SO 2 , C(O), NC(O), NC(S), OC(O), OC(S), C(NR 10 ), C(NOR 10 ), and a covalent bond; Z 1 , Z 2 , and Z 3 are independently selected from the group consisting of CR 8 and N; R 1 is selected from the group consisting of H, and substituted and unsubstituted arylalkyl, heteroarylalkyl, aryl, heteroaryl, heterocyclyl, cycloalkyl, heterocyclylalkyl, cycloalkylalkyl, alkenyl, alkynyl, and alkyl groups; R 2 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkylalkyl, aryl, and arylalkyl groups; R 3 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R 2 and R 3 may join together to form a ring containing at least two N atoms; R 4 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R 2 and R 4 may join together to form a ring containing at least two N atoms; R 5 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R 4 and R 5 , together with the nitrogen to which they are bound, form a substituted or unsubstituted heterocyclyl or heteroaryl group, or R 3 and R 5 may join together to form a ring containing at least two N atoms; R 6 and R 7 may be the same or different, and are each independently selected from the group consisting of H, Cl, I, F, Br, OH, NH 2 , CN, NO 2 , and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; R 8 is independently selected from the group consisting of H, Cl, I, F, Br, OH, NH 2 , CN, NO 2 , and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; and R 9 and R 10 are independently selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, cycloalkylalkyl, alkylcarbonyl, and arylcarbonyl groups. Compounds provided by the invention further include prodrugs of the compound of formula I, pharmaceutically acceptable salts thereof, stereoisomers thereof, tautomers thereof, hydrates thereof, hydrides thereof, or solvates thereof. In one embodiment, X is CH 2 and Y is C═O. In another embodiment, X is C═O and Y is CH 2 . In another embodiment, X is C═O and Y is C═O. In other embodiments, L is a covalent bond, and X and Y have the values according to any of the previous embodiments. In another embodiment, Z 1 , Z 2 , and Z 3 are all CH, and X, Y, and L have the values according to any of the previous embodiments. In another embodiment, at least one of Z 1 , Z 2 , or Z 3 is N, and X, Y, and L have the values according to any of the previous embodiments. In another embodiment, X, Y, L, Z 1 , Z 2 , and Z 3 have any of the values of previous embodiments, and R 1 is selected from the group consisting of substituted and unsubstituted arylalkyl, alkenyl, heteroarylalkyl, and heterocyclylalkyl groups. In another embodiment, X, Y, L, Z 1 , Z 2 , and Z 3 have any of the values of previous embodiments, and R 1 is 2,4-disubstituted phenethyl. In another embodiment, X, Y, L, Z 1 , Z 2 , and Z 3 have any of the values of previous embodiments, and R 1 is selected from the group consisting of 2,4-dihalophenethyl, and 2,4-dialkylphenethyl. In another embodiment, X, Y, L, Z 1 , Z 2 , and Z 3 have any of the values of previous embodiments, and R 1 is selected from the group consisting of phenethyl, 2,4-dichlorophenethyl, 4-methoxyphenethyl, 4-bromophenethyl, 4-methylphenethyl, 4-chlorophenethyl, 4-chlorobenzyl, 4-ethylphenethyl, cyclohexenylethyl, 2-methoxyphenethyl, 2-chlorophenethyl, 2-fluorophenethyl, 3-methoxyphenethyl, 3-fluorophenethyl, thienylethyl, indolylethyl, 4-hydroxyphenethyl, and 3,4-dimethoxyphenethyl. In another embodiment, X, Y, L, Z 1 , Z 2 , Z 3 , and R 1 have any of the values of previous embodiments, and R 2 is H. In another embodiment, X, Y, L, Z 1 , Z 2 , Z 3 , R 1 , and R 2 have any of the values of previous embodiments, and R 3 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, L, Z 1 , Z 2 , Z 3 , R 1 , and R 2 have any of the values of previous embodiments, and R 3 is selected from the group consisting of substituted and unsubstituted cycloalkyl, alkenyl, alkyl, and aryl groups. In another embodiment, X, Y, L, Z 1 , Z 2 , Z 3 , R 1 , and R 2 have any of the values of previous embodiments, and R 3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-alkylcyclohexyl, 2,2-dialkylcyclohexyl, 2,3-dialkylcyclohexyl, 2,4-dialkylcyclohexyl, 2,5-dialkylcyclohexyl, 2,6-dialkylcyclohexyl, 3,4-dialkylcyclohexyl, 3-alkylcyclohexyl, 4-alkylcyclohexyl, 3,3,5-trialkylcyclohexyl, cyclohexylmethyl, 2-aminocyclohexyl, 3-aminocyclohexyl, 4-aminocyclohexyl, 2,3-diaminocyclohexyl, 2,4-diaminocyclohexyl, 3,4-diaminocyclohexyl, 2,5-diaminocyclohexyl, 2,6-diaminocyclohexyl, 2,2-diaminocyclohexyl, 2-alkoxycyclohexyl, 3-alkoxycyclohexyl, 4-alkoxycyclohexyl, 2,3-dialkoxycyclohexyl, 2,4-dialkoxycyclohexyl, 3,4-dialkoxycyclohexyl, 2,5-dialkoxycyclohexyl, 2,6-dialkoxycyclohexyl, 2,2-dialkoxycyclohexyl, 2-alkylthiocyclohexyl, 3-alkylthiocyclohexyl, 4-alkylthiocyclohexyl, 2,3-dialkylthiocyclohexyl, 2,4-dialkylthiocyclohexyl, 3,4-dialkylthiocyclohexyl, 2,5-dialkylthiocyclohexyl, 2,6-dialkylthiocyclohexyl, 2,2-dialkylthiocyclohexyl, cyclopentyl, cycloheptyl, cyclohexenyl, isopropyl, n-butyl, cyclooctyl, 2-arylcyclohexyl, 2-phenylcyclohexyl, 2-arylalkylcyclohexyl, 2-benzylcyclohexyl, 4-phenylcyclohexyl, adamantyl, isocamphenyl, carenyl, 7,7-dialkylnorbornyl, bornyl, norbornyl, and decalinyl groups. In another embodiment, X, Y, L, Z 1 , Z 2 , Z 3 , R 1 , and R 2 have any of the values of previous embodiments, and R 3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-methylcyclohexyl, 2,2-dimethylcyclohexyl, 2,3-dimethylcyclohexyl, 2,4-dimethylcyclohexyl, 2,5-dimethylcyclohexyl, 2,6-dimethylcyclohexyl, 3,4-dimethylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, cyclohex-3-enyl, 3,3,5-trimethylcyclohexyl, 4-t-butylcyclohexyl, 2-methylcycloheptyl, cyclohexylmethyl, isopinocampheyl, 7,7-dimethylnorbornyl, 4-isopropylcyclohexyl, 2,6,6-trimethylbicyclo[3.1.1]heptyl, and 3-methylcycloheptyl. In another embodiment, X, Y, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 , and R 3 have any of the values of previous embodiments, and R 5 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 , and R 3 have any of the values of previous embodiments, R 4 is H, and R 5 is selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 , and R 3 have any of the values of previous embodiments, R 4 is H, and R 5 is selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 , and R 3 have any of the values of previous embodiments, and R 4 and R 5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 , and R 3 have any of the values of previous embodiments, and R 4 and R 5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 , and R 3 have any of the values of previous embodiments, and R 4 and R 5 , together with the nitrogen to which they are bound, form a substituted or unsubstituted piperazino, morpholino, pyrrolidino, piperidino, homopiperazino, or azepino group. In another embodiment, X, Y, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 , and R 3 have any of the values of previous embodiments, and R 4 and R 5 , together with the nitrogen to which they are bound, form a piperazino group optionally substituted by one or two alkyl groups, for example, one or two methyl groups. There has also been provided, in accordance with another aspect of the invention, a compound of formula II: wherein A is selected from the group consisting of C or CH; X and Y are independently selected from the group consisting of CH 2 , N, C═O, C═S, (CR 6 R 7 ) n , S═O, SO 2 , O, NR 9 , S, C(═O)—(CR 6 R 7 ) n , and C(═S)—(CR 6 R 7 ) n ; n is 1, 2, or 3; W is selected from the group consisting of Z 1 , Z 2 , and Z 3 are independently selected from the group consisting of CR 8 and N; L is selected from the group consisting of N, O, S, S═O, SO 2 , C(O), NC(O), NC(S), OC(O), OC(S), C(NR 10 ), C(NOR 10 ), and a covalent bond; R 1 is selected from the group consisting of H, and substituted and unsubstituted arylalkyl, heteroarylalkyl, aryl, heterocyclyl, cycloalkyl, heterocyclylalkyl, cycloalkylalkyl, alkenyl, alkynyl, and alkyl groups; R 2 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkylalkyl, aryl, and arylalkyl groups; R 3 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R 2 and R 3 may join together to form a ring containing at least two N atoms; R 4 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R 2 and R 4 may join together to form a ring containing at least two N atoms; R 5 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R 4 and R 5 , together with the nitrogen to which they are bound, form a substituted or unsubstituted heterocyclyl or heteroaryl group, or R 3 and R 5 may join together to form a ring containing at least two N atoms; R 6 and R 7 may be the same or different, and are each independently selected from the group consisting of H, Cl, I, F, Br, OH, NH 2 , CN, NO 2 , and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; R 8 is independently selected from the group consisting of H, Cl, I, F, Br, OH, NH 2 , CN, NO 2 , and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; and R 9 and R 10 are independently selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, cycloalkylalkyl, alkylcarbonyl, and arylcarbonyl groups. Compounds provided by the invention further include prodrugs of the compound of formula II, pharmaceutically acceptable salts thereof, stereoisomers thereof, tautomers thereof, hydrates thereof, hydrides thereof, or solvates thereof. In one embodiment, X is N, Y is NH, A is C, and the bond between X and A is a double bond. In another embodiment, X is NH, Y is N, A is C, and the bond between Y and A is a double bond. In another embodiment, A is C and the bond between either A and X or between A and Y is a double bond. In another embodiment, X, Y, and A have any of the values of previous embodiments, and L is a covalent bond. In another embodiment, X, Y, A, and L have any of the values of previous embodiments, and Z 1 , Z 2 , and Z 3 are all CH. In another embodiment, X, Y, A, and L have any of the values of previous embodiments, and at least one of Z 1 , Z 2 , or Z 3 is N. In another embodiment, X, Y, A, L, Z 1 , Z 2 , and Z 3 have any of the values of previous embodiments, and R 1 is selected from the group consisting of substituted and unsubstituted arylalkyl, alkenyl, heteroarylalkyl, and heterocyclylalkyl groups. In another embodiment, X, Y, A, L, Z 1 , Z 2 , and Z 3 have any of the values of previous embodiments, and R 1 is 2,4-disubstituted phenethyl. In another embodiment, X, Y, A, L, Z 1 , Z 2 , and Z 3 have any of the values of previous embodiments, and R 1 is selected from the group consisting of 2,4-dihalophenethyl, and 2,4-dialkylphenethyl. In another embodiment, X, Y, A, L, Z 1 , Z 2 , and Z 3 have any of the values of previous embodiments, and R 1 is selected from the group consisting of phenethyl, 2,4-dichlorophenethyl, 4-methoxyphenethyl, 4-bromophenethyl, 4-methylphenethyl, 4-chlorophenethyl, 4-chlorobenzyl, 4-ethylphenethyl, cyclohexenylethyl, 2-methoxyphenethyl, 2-chlorophenethyl, 2-fluorophenethyl, 3-methoxyphenethyl, 3-fluorophenethyl, thienylethyl, indolylethyl, 4-hydroxyphenethyl, and 3,4-dimethoxyphenethyl. In another embodiment, X, Y, A, L, Z 1 , Z 2 , Z 3 , and R 1 have any of the values of previous embodiments, and R 2 is H. In another embodiment, X, Y, A, L, Z 1 , Z 2 , Z 3 , R 1 , and R 2 have any of the values of previous embodiments, and R 3 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, A, L, Z 1 , Z 2 , Z 3 , R 1 , and R 2 have any of the values of previous embodiments, and R 3 is selected from the group consisting of substituted and unsubstituted cycloalkyl, alkenyl, alkyl, and aryl groups. In another embodiment, X, Y, A, L, Z 1 , Z 2 , Z 3 , R 1 , and R 2 have any of the values of previous embodiments, and R 3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-alkylcyclohexyl, 2,2-dialkylcyclohexyl, 2,3-dialkylcyclohexyl, 2,4-dialkylcyclohexyl, 2,5-dialkylcyclohexyl, 2,6-dialkylcyclohexyl, 3,4-dialkylcyclohexyl, 3-alkylcyclohexyl, 4-alkylcyclohexyl, 3,3,5-trialkylcyclohexyl, cyclohexylmethyl, 2-aminocyclohexyl, 3-aminocyclohexyl, 4-aminocyclohexyl, 2,3-diaminocyclohexyl, 2,4-diaminocyclohexyl, 3,4-diaminocyclohexyl, 2,5-diaminocyclohexyl, 2,6-diaminocyclohexyl, 2,2-diaminocyclohexyl, 2-alkoxycyclohexyl, 3-alkoxycyclohexyl, 4-alkoxycyclohexyl, 2,3-dialkoxycyclohexyl, 2,4-dialkoxycyclohexyl, 3,4-dialkoxycyclohexyl, 2,5-dialkoxycyclohexyl, 2,6-dialkoxycyclohexyl, 2,2-dialkoxycyclohexyl, 2-alkylthiocyclohexyl, 3-alkylthiocyclohexyl, 4-alkylthiocyclohexyl, 2,3-dialkylthiocyclohexyl, 2,4-dialkylthiocyclohexyl, 3,4-dialkylthiocyclohexyl, 2,5-dialkylthiocyclohexyl, 2,6-dialkylthiocyclohexyl, 2,2-dialkylthiocyclohexyl, cyclopentyl, cycloheptyl, cyclohexenyl, isopropyl, n-butyl, cyclooctyl, 2-arylcyclohexyl, 2-phenylcyclohexyl, 2-arylalkylcyclohexyl, 2-benzylcyclohexyl, 4-phenylcyclohexyl, adamantyl, isocamphenyl, carenyl, 7,7-dialkylnorbornyl, bornyl, norbornyl, and decalinyl groups. In another embodiment, X, Y, A, L, Z 1 , Z 2 , Z 3 , R 1 , and R 2 have any of the values of previous embodiments, and R 3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-methylcyclohexyl, 2,2-dimethylcyclohexyl, 2,3-dimethylcyclohexyl, 2,4-dimethylcyclohexyl, 2,5-dimethylcyclohexyl, 2,6-dimethylcyclohexyl, 3,4-dimethylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, cyclohex-3-enyl, 3,3,5-trimethylcyclohexyl, 4-t-butylcyclohexyl, 2-methylcycloheptyl, cyclohexylmethyl, isopinocampheyl, 7,7-dimethylnorbornyl, 4-isopropylcyclohexyl, 2,6,6-trimethylbicyclo[3.1.1]heptyl, and 3-methylcycloheptyl. In another embodiment, X, Y, A, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 and R 3 have any of the values of previous embodiments, and R 5 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, A, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 and R 3 have any of the values of previous embodiments, R 4 is H, and R 5 is selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, A, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 and R 3 have any of the values of previous embodiments, R 4 is H, and R 5 is selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, A, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 and R 3 have any of the values of previous embodiments, and R 4 and R 5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, A, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 and R 3 have any of the values of previous embodiments, and R 4 and R 5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, A, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 and R 3 have any of the values of previous embodiments, and R 4 and R 5 , together with the nitrogen to which they are bound, form a substituted or unsubstituted piperazino, morpholino, pyrrolidino, piperidino, homopiperazino, or azepino group. In another embodiment, X, Y, A, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 and R 3 have any of the values of previous embodiments, and R 4 and R 5 , together with the nitrogen to which they are bound, form a piperazino group optionally substituted by one or two alkyl groups, for example, one or two methyl groups. There has also been provided, in accordance with another aspect of the invention, a compound of formula III: wherein X and Y are independently selected from the group consisting of CH 2 , N, C═O, NR 9 , C═S, S═O, SO 2 , O, S, (CR 6 R 7 ) n , C(═O)—(CR 6 R 7 ) n , and C(═S)—(CR 6 R 7 ) n ; D is selected from the group consisting of N, and C; If X is N, then Y is not N, but may be NH; If Y is N, then X is not N, but may be NH; If X is CH 2 , then Y is not CH 2 ; If Y is CH 2 , then X is not CH 2 ; If X is NH, then Y is not NH; If Y is NH, then X is not NH; L is selected from the group consisting of N, O, S, S═O, SO 2 , C(O), NC(O), NC(S), OC(O), OC(S), C(NR 10 ), C(NOR 10 ), and a covalent bond; W is selected from the group consisting of Z 1 , Z 2 , and Z 3 are independently selected from the group consisting of CR 8 and N; R 1 is selected from the group consisting of H, and substituted and unsubstituted arylalkyl, heteroarylalkyl, aryl, heteroaryl, heterocyclyl, cycloalkyl, heterocyclylalkyl, cycloalkylalkyl, alkenyl, alkynyl, and alkyl groups; R 2 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkylalkyl, aryl, and arylalkyl groups; R 3 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R 2 and R 3 may join together to form a ring containing at least two N atoms; R 4 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R 2 and R 4 may join together to form a ring containing at least two N atoms; R 5 is selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups, or R 4 and R 5 , together with the nitrogen to which they are bound, form a substituted or unsubstituted heterocyclyl or heteroaryl group, or R 3 and R 5 may join together to form a ring containing at least two N atoms; R 6 and R 7 may be the same or different, and are each independently selected from the group consisting of H, Cl, I, F, Br, OH, NH 2 , CN, NO 2 , and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkyiaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; R 8 is independently selected from the group consisting of H, Cl, I, F, Br, OH, NH 2 , CN, NO 2 , and substituted and unsubstituted alkoxy, amino, alkyl, alkenyl, alkynyl, alkylamino, dialkylamino, cycloalkyl, heterocyclylamino, heteroarylamino, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl, and heteroarylaminocarbonyl groups; and R 9 and R 10 are independently selected from the group consisting of H, and substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, cycloalkylalkyl, alkylcarbonyl, and arylcarbonyl groups. Compounds provided by the invention further include prodrugs of the compound of formula III, pharmaceutically acceptable salts thereof, stereoisomers thereof, tautomers thereof, hydrates thereof, hydrides thereof, or solvates thereof. In one embodiment, X is CH 2 , Y is C═O, and D is N. In another embodiment, X is C═O, Y is CH 2 , and D is N. In another embodiment, X is C═O, Y is C═O, and D is N. In another embodiment, X is N, Y is NH, D is C, and the bond between X and D is a double bond. In another embodiment, X is NH, Y is N, D is C, and the bond between Y and D is a double bond. In another embodiment, X, Y, and D have any of the values of previous embodiments, and L is a covalent bond. In another embodiment, X, Y, D, and L have any of the values of previous embodiments, and Z 1 , Z 2 , and Z 3 are all CH. In another embodiment, X, Y, D, and L have any of the values of previous embodiments, and at least one of Z 1 , Z 2 , or Z 3 is N. In another embodiment, X, Y, D, L, Z 1 , Z 2 , and Z 3 have any of the values of previous embodiments, and R 1 is selected from the group consisting of substituted and unsubstituted arylalkyl, alkenyl, heteroarylalkyl, and heterocyclylalkyl groups. In another embodiment, X, Y, D, L, Z 1 , Z 2 , and Z 3 have any of the values of previous embodiments, and R 1 is 2,4-disubstituted phenethyl. In another embodiment, X, Y, D, L, Z 1 , Z 2 , and Z 3 have any of the values of previous embodiments, and R 1 is selected from the group consisting of 2,4-dihalophenethyl, and 2,4-dialkylphenethyl. In another embodiment, X, Y, D, L, Z 1 , Z 2 , and Z 3 have any of the values of previous embodiments, and R 1 is selected from the group consisting of phenethyl, 2,4-dichlorophenethyl, 4-methoxyphenethyl, 4-bromophenethyl, 4-methylphenethyl, 4-chlorophenethyl, 4-chlorobenzyl, 4-ethylphenethyl, cyclohexenylethyl, 2-methoxyphenethyl, 2-chlorophenethyl, 2-fluorophenethyl, 3-methoxyphenethyl, 3-fluorophenethyl, thienylethyl, indolylethyl, 4-hydroxyphenethyl, and 3,4-dimethoxyphenethyl. In another embodiment, X, Y, D, L, Z 1 , Z 2 , Z 3 , and R 1 have any of the values of previous embodiments, and R 2 is H. In another embodiment, X, Y, D, L, Z 1 , Z 2 , Z 3 , R 1 , and R 2 have any of the values of previous embodiments, and R 3 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, heteroaryl, heterocyclyl, heterocyclylalkyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, D, L, Z 1 , Z 2 , Z 3 , R 1 , and R 2 have any of the values of previous embodiments, and R 3 is selected from the group consisting of substituted and unsubstituted cycloalkyl, alkenyl, alkyl, and aryl groups. In another embodiment, X, Y, D, L, Z 1 , Z 2 , Z 3 , R 1 , and R 2 have any of the values of previous embodiments, and R 3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-alkylcyclohexyl, 2,2-dialkylcyclohexyl, 2,3-dialkylcyclohexyl, 2,4-dialkylcyclohexyl, 2,5-dialkylcyclohexyl, 2,6-dialkylcyclohexyl, 3,4-dialkylcyclohexyl, 3-alkylcyclohexyl, 4-alkylcyclohexyl, 3,3,5-trialkylcyclohexyl, cyclohexylmethyl, 2-aminocyclohexyl, 3-aminocyclohexyl, 4-aminocyclohexyl, 2,3-diaminocyclohexyl, 2,4-diaminocyclohexyl, 3,4-diaminocyclohexyl, 2,5-diaminocyclohexyl, 2,6-diaminocyclohexyl, 2,2-diaminocyclohexyl, 2-alkoxycyclohexyl, 3-alkoxycyclohexyl, 4-alkoxycyclohexyl, 2,3-dialkoxycyclohexyl, 2,4-dialkoxycyclohexyl, 3,4-dialkoxycyclohexyl, 2,5-dialkoxycyclohexyl, 2,6-dialkoxycyclohexyl, 2,2-dialkoxycyclohexyl, 2-alkylthiocyclohexyl, 3-alkylthiocyclohexyl, 4-alkylthiocyclohexyl, 2,3-dialkylthiocyclohexyl, 2,4-dialkylthiocyclohexyl, 3,4-dialkylthiocyclohexyl, 2,5-dialkylthiocyclohexyl, 2,6-dialkylthiocyclohexyl, 2,2-dialkylthiocyclohexyl, cyclopentyl, cycloheptyl, cyclohexenyl, isopropyl, n-butyl, cyclooctyl, 2-arylcyclohexyl, 2-phenylcyclohexyl, 2-arylalkylcyclohexyl, 2-benzylcyclohexyl, 4-phenylcyclohexyl, adamantyl, isocamphenyl, carenyl, 7,7-dialkylnorbornyl, bornyl, norbornyl, and decalinyl groups. In another embodiment, X, Y, D, L, Z 1 , Z 2 , Z 3 , R 1 , and R 2 have any of the values of previous embodiments, and R 3 is selected from the group consisting of substituted and unsubstituted cyclohexyl, 2-methylcyclohexyl, 2,2-dimethylcyclohexyl, 2,3-dimethylcyclohexyl, 2,4-dimethylcyclohexyl, 2,5-dimethylcyclohexyl, 2,6-dimethylcyclohexyl, 3,4-dimethylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, cyclohex-3-enyl, 3,3,5-trimethylcyclohexyl, 4-t-butylcyclohexyl, 2-methylcycloheptyl, cyclohexylmethyl, isopinocampheyl, 7,7-dimethylnorbornyl, 4-isopropylcyclohexyl, 2,6,6-trimethylbicyclo[3.1.1]heptyl, and 3-methylcycloheptyl. In another embodiment, X, Y, D, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 and R 3 have any of the values of previous embodiments, and R 5 is selected from the group consisting of substituted and unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and cycloalkylalkyl groups. In another embodiment, X, Y, D, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 and R 3 have any of the values of previous embodiments, R 4 is H, and R 5 is selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, D, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 and R 3 have any of the values of previous embodiments, R 4 is H, and R 5 is selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, D, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 and R 3 have any of the values of previous embodiments, and R 4 and R 5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted alkyl, arylalkyl, and heteroarylalkyl groups. In another embodiment, X, Y, D, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 and R 3 have any of the values of previous embodiments, and R 4 and R 5 may be the same or different and are each independently selected from the group consisting of substituted and unsubstituted dialkylaminoethyl, 4-ethylbenzyl, 3-chlorobenzyl, 2,4-dichlorobenzyl, 3-methylbenzyl, benzyl, 4-fluorobenzyl, 3-methoxybenzyl, 2-chlorobenzyl, and thiophene groups. In another embodiment, X, Y, D, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 and R 3 have any of the values of previous embodiments, and R 4 and R 5 , together with the nitrogen to which they are bound, form a substituted or unsubstituted piperazino, morpholino, pyrrolidino, piperidino, homopiperazino, or azepino group. In another embodiment, X, Y, D, L, Z 1 , Z 2 , Z 3 , R 1 , R 2 and R 3 have any of the values of previous embodiments, and R 4 and R 5 , together with the nitrogen to which they are bound, form a piperazino group optionally substituted by one or two alkyl groups, for example, one or two methyl groups. There has also been provided, in accordance with another aspect of the invention, a composition comprising a compound according to the instant invention and a pharmaceutically acceptable carrier. There has also been provided, in accordance with another aspect of the invention, a method of activating MC4-R, comprising administering to a subject in need thereof, an effective amount of a compound or composition of the instant invention. There has also been provided, in accordance with another aspect of the invention, a method of treating an MC4-R mediated disease, comprising administering to a subject in need thereof, a compound or composition of the instant invention. In one embodiment, a disease to be treated by those methods of the instant invention is obesity, or type I or type II diabetes. There has also been provided, in accordance with another aspect of the invention, a method of decreasing blood glucose levels, comprising administering to a subject in need thereof, a compound or composition of the instant invention. In various alternative embodiments, the composition is administered orally, rectally, by subcutaneous injection, by intravenous injection, by intramuscular injection, or by intraperitoneal injection. Other objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. detailed-description description="Detailed Description" end="lead"? | 20040405 | 20070313 | 20050217 | 75887.0 | 0 | SHAMEEM, GOLAM M | NOVEL GUANIDINO COMPOUNDS | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,818,749 | ACCEPTED | System and method for dynamically performing storage operations in a computer network | Methods and systems are described for performing storage operations on electronic data in a network. In response to the initiation of a storage operation and according to a first set of selection logic, a media management component is selected to manage the storage operation. In response to the initiation of a storage operation and according to a second set of selection logic, a network storage device to associate with the storage operation. The selected media management component and the selected network storage device perform the storage operation on the electronic data. | 1. A computerized method for dynamically performing a storage operation on data in a network, the method comprising: selecting, in response to the initiation of the storage operation and according to a first set of selection logic, a media management component to manage the storage operation; selecting, in response to the initiation of the storage operation and according to a second set of selection logic, a network storage device to associate with the storage operation; and using the selected media management component and the selected network storage device to perform the storage operation on the data. 2. The method of claim 1, wherein selecting in response to the initiation of the storage operation comprises selecting in response to a backup storage operation. 3. The method of claim 1, wherein selecting in response to the initiation of the storage operation comprises selecting in response to an archive storage operation. 4. The method of claim 1, wherein selecting in response to the initiation of the storage operation comprises selecting in response to a restore storage operation. 5. The method of claim 1, wherein selecting in response to the initiation of the storage operation comprises selecting in response to an auxiliary copy storage operation. 6. The method of claim 1, wherein selecting according to a first set of selection logic comprises selecting according to a user preference. 7. The method of claim 1, wherein selecting according to a first set of selection logic comprises selecting according to a storage policy. 8. The method of claim 1, wherein selecting according to a first set of selection logic comprises selecting according to availability of a network component. 9. The method of claim 1, wherein selecting according to a first set of selection logic comprises selecting according to efficiency of a storage operation. 10. The method of claim 1, wherein selecting according to a first set of selection logic comprises selecting according to availability of a network path. 11. The method of claim 1, wherein selecting according to a first set of selection logic comprises selecting according to ability to perform a LAN-free storage operation. 12. The method of claim 1, wherein selecting according to a first set of selection logic comprises selecting according to ability to perform an auxiliary copy storage operation. 13. The method of claim 1, wherein selecting a media management component comprises selecting a media agent. 14. The method of claim 1, wherein selecting according to a second set of selection logic comprises selecting according to a user preference. 15. The method of claim 1, wherein selecting according to a second set of selection logic comprises selecting according to a storage policy. 16. The method of claim 1, wherein selecting according to a second set of selection logic comprises selecting according to availability of a network component. 17. The method of claim 1, wherein selecting according to a second set of selection logic comprises selecting according to efficiency of a storage operation. 18. The method of claim 1, wherein selecting according to a second set of selection logic comprises selecting according to availability of a network path. 19. The method of claim 1, wherein selecting according to a second set of selection logic comprises selecting according to ability to perform a LAN-free storage operation. 20. The method of claim 1, wherein selecting according to a second set of selection logic comprises selecting according to ability to perform an auxiliary copy storage operation. 21. The method of claim 1, wherein selecting a storage device comprises selecting a storage device from the group consisting of: a tape media storage device, a magnetic media storage device, and an optical media storage device. 22. The method of claim 1, wherein performing the storage operation is performed according to a set of storage preferences. 23. The method of claim 22, wherein performing the storage operation according to a set of storage preferences comprises performing the storage operation according to a storage policy. 24. The method of claim 22, wherein performing the storage operation according to a set of storage preferences comprises performing the storage operation according to a set of user preferences. 25. A system for dynamically performing storage operations on electronic data in a computer network, the system comprising: one or more media management devices; one or more storage devices; and a storage manager component programmed to: select, in response to the initiation of a storage operation and according to a first set of selection logic, a media management component to manage the storage operation; and select, in response to the initiation of a storage operation and according to a second set of selection logic, a network storage device to associate with the storage operation. 26. The system of claim 25, wherein the storage operation comprises a backup storage operation. 27. The system of claim 25, wherein the storage operation comprises an archive storage operation. 28. The system of claim 25, wherein the storage operation comprises a restore storage operation. 29. The system of claim 25, wherein the storage operation comprises an auxiliary copy storage operation. 30. The system of claim 25, wherein the first set of selection logic comprises a user preference. 31. The system of claim 25, wherein the first set of selection logic comprises a storage policy 32. The system of claim 25, wherein the first set of selection logic comprises availability of a network component. 33. The system of claim 25, wherein the first set of selection logic comprises efficiency of a storage operation 34. The system of claim 25, wherein the first set of selection logic comprises availability of a network path. 35. The system of claim 25, wherein the first set of selection logic comprises ability to perform a LAN-free storage operation. 36. The system of claim 25, wherein the first set of selection logic comprises ability to perform an auxiliary copy storage operation. 37. The system of claim 25, wherein the media management component comprises a media agent. 38. The system of claim 25, wherein the second set of selection logic comprises a user preference. 39. The system of claim 25, wherein the second set of selection logic comprises a storage policy 40. The system of claim 25, wherein the second set of selection logic comprises availability of a network component. 41. The system of claim 25, wherein the second set of selection logic comprises efficiency of a storage operation 42. The system of claim 25, wherein the second set of selection logic comprises availability of a network path. 43. The system of claim 25, wherein the second set of selection logic comprises ability to perform a LAN-free storage operation. 44. The system of claim 25, wherein the second set of selection logic comprises ability to perform an auxiliary copy storage operation. 45. The system of claim 25, wherein the storage device comprises a storage device from the group consisting of: a tape media storage device, a magnetic media storage device, and an optical media storage device. 46. The system of claim 25, wherein the storage operation is performed according to a set of storage preferences. 47. The system of claim 46, wherein the set of storage preferences comprises a storage policy. 48. The system of claim 46, wherein the set of storage preferences comprises a set of user preferences. | RELATED APPLICATIONS This application claims priority to Provisional Application No. 60/460,234, titled SYSTEM AND METHOD FOR PERFORMING STORAGE OPERATIONS IN A COMPUTER NETWORK, filed Apr. 3, 2003 which is hereby incorporated herein by reference in its entirety. This application is also related to the following patents and pending applications, each of which is hereby incorporated herein by reference in its entirety: U.S. Pat. No. 6,418,478, titled PIPELINED HIGH SPEED DATA TRANSFER MECHANISM, issued Jul. 9, 2002, attorney docket number 4982/6; application Ser. No. 09/610,738, titled MODULAR BACKUP AND RETRIEVAL SYSTEM USED IN CONJUNCTION WITH A STORAGE AREA NETWORK, filed Jul. 6,2000, attorney docket number 4982/8; application Ser. No. 09/744,268, titled LOGICAL VIEW AND ACCESS TO PHYSICAL STORAGE IN MODULAR DATA AND STORAGE MANAGEMENT SYSTEM, filed Jan. 30, 2001, attorney docket number 4982/10; and Application Ser. No. 60/409,183, titled DYNAMIC STORAGE DEVICE POOLING IN A COMPUTER SYSTEM, filed Sep. 9, 2002, attorney docket number 4982/18PROV. COPYRIGHT NOTICE A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosures, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. BACKGROUND OF THE INVENTION The invention disclosed herein relates generally to performing storage operations on electronic data in a computer network. More particularly, the present invention relates to selecting, in response to the initiation of a storage operation and according to selection logic, a media management component and a network storage device to perform storage operations on electronic data. Storage of electronic data has evolved through many forms. During the early development of the computer, storage of this data was limited to individual computers. Electronic data was stored in the Random Access Memory (RAM) or some other storage medium such as a hard drive or tape drive that was an actual part of the individual computer. Later, with the advent of networked computing, storage of electronic data gradually migrated from the individual computer to stand-alone storage devices accessible via a network. These individual network storage devices soon evolved in the form of networkable tape drives, optical libraries, Redundant Arrays of Inexpensive Disks (RAID), CD-ROM jukeboxes, and other devices. Common architectures included drive pools, which generally are logical collections of drives with associated media groups including the tapes or other storage media used by a given drive pool. Serial, parallel, Small Computer System Interface (SCSI), or other cables, directly connected these stand-alone storage devices to individual computers that were part of a network of other computers such as a Local Area Network (LAN) or a Wide Area Network (WAN). Each individual computer on the network controlled the storage devices that were physically attached to that computer and could also access the storage devices of the other network computers to perform backups, transaction processing, file sharing, and other storage-related operations. Network Attached Storage (NAS) is another storage scheme using stand-alone storage devices in a LAN or other such network. In NAS, a storage controller computer still “owns” the storage device to the exclusion of other computers on the network, but the SCSI or other cabling directly connecting that storage device to the individual controller or owner computer is eliminated. Instead, storage devices are directly attached to the network itself. Yet another network storage scheme is modular storage architecture which is more fully described in application Ser. No. 09/610,738 and application Ser. No. 09/744,268. An example of such a software application is the Galaxy™ system, by CommVault Systems of Oceanport, N.J. The Galaxy™ system is a multi-tiered storage management solution which includes, among other components, a storage manager, one or more media agents, and one or more storage devices. The storage manager directs storage operations of client data to storage devices such magnetic and optical media libraries. Media agents are storage controller computers that serve as intermediary devices managing the flow of data from client information stores to individual storage devices. Each storage device is uniquely associated with a particular media agent and this association is tracked by the storage manager. A common feature shared by all of the above-described network architectures is the static relationship between storage controller computers and storage devices. In these traditional network architectures, storage devices can each only be connected, virtually or physically, to a single storage controller computer. Only the storage controller computer to which a particular device is physically connected has read/write access to that device. A drive pool and its associated media group, for example, can only be controlled by the computer to which it is directly connected. Therefore, all backup from other storage controller computers needs to be sent via the network before it can be stored on the storage device connected to the first storage controller computer. At times, storage solutions in some of the above-described network architectures including LAN, NAS, and modular storage systems may cause overloading of network traffic during certain operations associated with use of storage devices on the network. The network cable has a limited amount of bandwidth that must be shared among all the computers on the network. The capacity of most LAN or network cabling is measured in megabits per second (mbps) with 10 mbps and 100mbps being standard. During common operations such as system backups, transaction processing, file copies, and other similar operations, network traffic often becomes overloaded as hundreds of megabytes (MB) and gigabytes (GB) of information are sent over the network to the associated storage devices. The capacity of the network computers to stream data over the network to the associated storage devices in this manner is greater than the bandwidth capacity of the cabling itself so ordinary network activity and communication slows to a crawl. As long as the storage devices are attached to the LAN or other network, this bandwidth issue remains a problem. The Storage Area Network (SAN) is a highly-evolved network architecture designed to facilitate transport of electronic data and address this bandwidth issue. SAN architecture requires at least two networks. First, there is the traditional network described above which is typically a LAN or other such network designed to transport ordinary traffic between network computers. Then, there is the SAN itself which is a second network that is attached to the servers of the first network. The SAN is a separate network generally reserved for bandwidth-intensive operations such as backups, transaction processing, and the like also described above. The cabling used in the SAN is usually of much higher bandwidth capacity than that used in the first network such as the LAN and the communication protocols used over the SAN cabling are optimized for bandwidth-intensive traffic. Most importantly, the storage devices used by the network computers for the bandwidth-intensive operations are attached to the SAN rather than the LAN. Thus, when the bandwidth-intensive operations are required, they take place over the SAN and the LAN remains unaffected. CommVault's proprietary DataPipe™ mechanism further described in U.S. Pat. No. 6,418,478 is used with a SAN to further reduce bandwidth constraints. The DataPipe™ is the transport protocol used to facilitate and optimize electronic data transfers taking place over a Storage Area Network (SAN) as opposed to those taking place over a LAN using NAS. None of these solutions, however, address the static relationship between individual storage controller computers and individual storage devices. LANs, WANs, and even SANs using a DataPipe™ all require a static relationship between storage controller computer and storage device since each storage device on the network is uniquely owned by a storage controller computer. As discussed, when a storage device in this traditional architecture is assigned to a storage controller computer, that storage controller computer owns the device indefinitely and to the exclusion of other computers on the network. This is also true with both logical and physical storage volumes. One computer cannot control the drive pool and media group being that is controlled by another. Requests to store and retrieve data from such a drive pool and media group would have to first pass through the controlling computer. Such a static relationship between storage controller computer and storage device often leads to an inefficient use of resources. For example, if each storage controller computer needs access to two storage devices and there are five storage controller computers in the network, then a total of ten storage devices will be required. The actual amount of work each of the ten storage devices performs might be much less than the workload capacity of each storage device. Such underutilization of storage device resources cannot be solved when a static relationship is required between storage device and storage controller computer. If the static relationship were dynamic, however, and storage controller computers could actually share devices, then this underutilization can be addressed. Assuming in the above example that each of the five storage controller computers only uses ten percent of each device's workload capacity, then if all the storage controller computers could actually share the same two storage devices, eight of the storage devices could be eliminated without loss of performance or capability. Furthermore, none of these existing solutions provide access to storage devices in the event of a storage controller failure. For example, if a storage controller computer were unavailable due to a hardware or software malfunction, then other computers on the network would not be able to access data stored on any storage device associated with the storage controller computer. Until the storage controller computer was brought back online, the data contained on any associated storage device would be effectively unrecoverable. If the association between the storage controller computer and a storage device were not static, however, then another storage controller computer could bypass the unavailable storage controller computer and access the storage device to retrieve the data. There is thus also a need for a system which enables dynamic association of storage controller computers and storage devices SUMMARY OF THE INVENTION The present invention addresses, among other things, the problems discussed above performing storage operations on electronic data in a computer network. In accordance with some aspects of the present invention, computerized methods are provided for dynamically selecting media agents and storage devices to perform storage operations on data. The system selects, in response to the initiation of a storage operation and according to a first set of selection logic, a media management component to manage the storage operation. The system also selects, in response to the initiation of the storage operation and according to a second set of selection logic, a network storage device to associate with the storage operation. Using the selected media management component and the selected network storage device, the system performs the storage operation on the data. In another embodiment, the system provides a method for sharing a magnetic media volume in a network. The system, in response to a volume sharing request, removes an association between a first media management component and the magnetic media volume. For example, in some embodiments, the system removes an index entry associating a first media management component and the magnetic media volume. In response to a volume sharing request and according to a set of selection logic, the system associates a second media management component with the magnetic media volume. For example, in some embodiments the system creates an index entry associating the second media management component and the magnetic media volume. In other embodiments, the system mounts the magnetic media volume to the second media management component. BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated in the figures of the accompanying drawings which are meant to be exemplary and not limiting, in which like references are intended to refer to like or corresponding parts, and in which: FIG. 1 is a block diagram of a network architecture for a system to perform storage operations on electronic data in a computer network according to an embodiment of the invention; FIG. 2 is a block diagram of an exemplary tape library storage device for a system to perform storage operations on electronic data in a computer network according to an embodiment of the invention; and FIG. 3 is a block diagram of an exemplary magnetic media storage device for a system to perform storage operations on electronic data in a computer network according to an embodiment of the invention; FIG. 4 is a flow chart of a method for performing storage operations on electronic data in a computer network according to an embodiment of the invention; FIG. 5 is a flow chart of a method to archive electronic data in a system to perform storage operations on electronic data in a computer network according to an embodiment of the invention; FIG. 6 is a flow chart of a method for restoring or auxiliary copying electronic data in a system to perform storage operations on electronic data in a computer network according to an embodiment of the invention; FIG. 7 is a flow chart of a method to restore a storage index in a system to perform storage operations on electronic data in a computer network according to an embodiment of the invention; and FIG. 8 is a flow diagram of a method to perform dynamic volume sharing according to one embodiment of the invention. DETAILED DESCRIPTION With reference to FIGS. 1 through 7, embodiments of the invention are presented. FIG. 1 presents a block diagram of a network architecture for a system to perform storage operations on electronic data in a computer network according to an embodiment of the invention. As shown, the system includes a storage manager 100 and one or more of the following: a client 85, an information store 90, a data agent 95, a media agent 105, an index cache 110, and a storage device 115. The system and elements thereof are exemplary of a three-tier backup system such as the CommVault Galaxy backup system, available from CommVault Systems, Inc. of Oceanport, N.J., and further described in application Ser. No. 09/610,738 which is incorporated herein by reference in its entirety. A data agent 95 is generally a software module that is generally responsible for archiving, migrating, and recovering data of a client computer 85 stored in an information store 90 or other memory location. Each client computer 85 has at least one data agent 95 and the system can support many client computers 85. The system provides a plurality of data agents 95 each of which is intended to backup, migrate, and recover data associated with a different application. For example, different individual data agents 95 may be designed to handle Microsoft Exchange data, Lotus Notes data, Microsoft Windows 2000 file system data, Microsoft Active Directory Objects data, and other types of data known in the art. If a client computer 85 has two or more types of data, one data agent 95 is generally required for each data type to archive, migrate, and restore the client computer 85 data. For example, to backup, migrate, and restore all of the data on a Microsoft Exchange 2000 server, the client computer 85 would use one Microsoft Exchange 2000 Mailbox data agent 95 to backup the Exchange 2000 mailboxes, one Microsoft Exchange 2000 Database data agent 95 to backup the Exchange 2000 databases, one Microsoft Exchange 2000 Public Folder data agent 95 to backup the Exchange 2000 Public Folders, and one Microsoft Windows 2000 File System data agent 95 to backup the client computer's 85 file system. These data agents 95 would be treated as four separate data agents 95 by the system even though they reside on the same client computer 85. The storage manager 100 is generally a software module or application that coordinates and controls the system. The storage manager 100 communicates with all elements of the system including client computers 85, data agents 95, media agents 105, and storage devices 115, to initiate and manage system backups, migrations, and recoveries. A media agent 105 is generally a software module that conducts data, as directed by the storage manager 100, between the client computer 85 and one or more storage devices 115 such as a tape library, a magnetic media storage device, an optical media storage device, or other storage device. The media agent 105 is communicatively coupled with and controls the storage device 115. For example, the media agent 105 might instruct the storage device 115 to use a robotic arm or other means to load or eject a media cartridge, and to archive, migrate, or restore application specific data. The media agent 105 generally communicates with the storage device 115 via a local bus such as a SCSI adaptor. In some embodiments, the storage device 115 is communicatively coupled to the data agent 105 via a Storage Area Network (“SAN”). Each media agent 105 maintain an index cache 110 which stores index data the system generates during backup, migration, and restore storage operations as further described herein. For example, storage operations for Microsoft Exchange data generate index data. Index data provides the system with an efficient mechanism for locating user files for recovery operations. This index data is generally stored with the data backed up to the storage device 115, and the media agent 105 that controls the storage operation also writes an additional copy of the index data to its index cache 110. The data in the media agent 105 index cache 110 is thus readily available to the system for use in storage operations and other activities without having to be first retrieved from the storage device 115. The storage manager 100 also maintains an index cache 110. Index data is also used to indicate logical associations between components of the system, user preferences, management tasks, and other useful data. For example, the storage manager 100 might use its index cache 110 to track logical associations between media agents 105 and storage devices 115. Index caches 110 typically reside on their corresponding storage component's hard disk or other fixed storage device. Like any cache, the index cache 110 has finite capacity and the amount of index data that can be maintained directly corresponds to the size of that portion of the disk that is allocated to the index cache 110. In one embodiment, the system manages the index cache 110 on a least recently used (“LRU”) basis as known in the art. When the capacity of the index cache 110 is reached, the system overwrites those files in the index cache 110 that have been least recently accessed with the new index data. In some embodiments, before data in the index cache 110 is overwritten, the data is copied to an index cache 110 copy in a storage device 115. If a recovery operation requires data that is no longer stored in the index cache 110, such as in the case of a cache miss, the system recovers the index data from the index cache 110 copy stored in the storage device 115. In some embodiments, components of the system may reside and execute on the same computer. In some embodiments, a client computer 85 component such as a data agent 95, a media agent 105, or a storage manager 100 coordinates and directs local archiving, migration, and retrieval application functions as further described in application Ser. No. 09/610,738. This client computer 85 component can function independently or together with other similar client computer 85 components. FIG. 2 presents a block diagram of an exemplary tape library storage device 120 for a system to perform storage operations on electronic data in a computer network according to an embodiment of the invention. The tape library storage device 120 contains tapes 140 and drives 125, 130, and 135. The tapes 140 store electronic data containing backups of application data, user preferences, system information, and other useful information known in the art. Drives 125, 130, and 135 are used to store and retrieve electronic data from the tapes 140. In some embodiments, drives 125, 130, and 135 function as a drive pool, as further described in Application Ser. No. 60/409,183 which is hereby incorporated herein by reference in its entirety. A drive pool is generally a logical concept associated with a storage policy. Storage policies representing storage patterns and preferences are more fully discussed in application Ser. No. 09/744,268 which is hereby incorporated by reference herein in its entirety. The drive pool is identified by a set of drives within a tape library storage device 120 as pointed to by one or more media agents 105. For example, a drive pool known as DP1 consisting of drives 125 and 130 in tape library 120 known as LIB1 could be associated by a storage policy with a first media agent 105 MA1 in an index cache 110 entry as follows: LIB1/MA1/DP1. A second drive pool consisting of drives 130, 135, and 140 within the tape library storage device 120 associated with the same media agent 105 might be expressed in the index cache 110 as follows: LIB1/MA1/DP2. Previously, however, drive pools had a static association with a particular media agent 105. A drive pool associated with a first media agent 105 could not be logically associated with a second drive pool associated with a second media agent 105. An index cache 110 entry associating a drive pool with a media agent 105 and other system components might, for example, specify a media library or media group, a media agent, and a drive pool. Only one of each component could be specified in a particular index cache 110 entry. Thus, such drive pools were logically exclusive and separate entries in an index cache 110 entry for a storage policy and could be logically represented as: ❘ LIB1 / MA1 / DP1 LIB1 / MA2 / DP2 As further described herein, the present invention permits logical association of drive pools associated with different media agents 105. Multiple drive pools, media agents, and other system components can be associated in a single index cache 110 entry. Thus, for example, an index cache 110 entry for a storage policy, according to the present invention, may combine the two previous entries instead and thus be logically represented as: LIB1 / MA1 / DP1 / DP2 LIB1 / MA2 / DP2 / DP1 In addition and as further described herein, tapes 140 are associated by the system with drive pools or storage policies, and not with individual drives 125, 130, and 135. The recording format used to archive electronic data is a property of both its media group and its associated drive pool. A media group is a collection of tapes 140 or other storage media assigned to a specific storage policy. The media group dynamically points to different drive pools, even to those with different recording formats since the system updates the recording format of the media group in a media group table stored in the index cache 110 of the storage manager 100. Previously, tapes 140 associated with drive pools could share individual drives 125, 130, and 135, but tapes 140 associated with each drive pool remained logically separate by, among other factors, media groups. Thus, a given set of tapes 140 associated with a particular drive pool and storing data associated with a first storage policy copy could not also store data from a second storage policy copy. An index cache 110 entry would thus associate different tape sets 140 with different media agents 105, storage policies, drive pools, and other system components. For example, two different tape sets might be associated in two index cache 110 entries as follows: ❘ storage policy 1 : media agent 1 : drive pool 1 : tape set 1 storage policy 2 : media agent 2 : drive pool 2 : tape set 2 All components are thus uniquely associated and require separate index cache 110 entries. By contrast, the present invention, as further described herein, permits data associated with a particular storage policy copy to be stored on and share tapes 140, and other pieces or removable media such as optical discs, associated with and sharing one or more drive pools or storage policy copies. Data from each storage policy copy is appended to tapes 140 shared by other storage policy copies. Thus, a storage policy copy is shared between many media agents 105 in a dynamic drive pooling setting with tapes 140 also being shared by the different media agents 105 and storage policies. Tapes 140 can be located in any storage device 115 and tapes 140 for a given storage policy copy can even be spread across multiple storage devices 115. Thus, an index cache entry would associate multiple tape sets 140 with multiple media agents, storage policies, drive pools, and other system components. For example, two different tape sets from the previous example of index entries might be associated in a single index cache 110 entry as follows: storage policy 1 : media agent 1 : drive pool 1 : tape set 1 : tape set 2 storage policy 2 : media agent 2 : drive pool 2 : tape set 1 : tape set 2 In addition to tape sets 140, a single index cache 110 entry can also specify and associate multiple media agents 105, storage policies, drive pools, network pathways, and other components. Similarly, different media agents 105 and storage policies can also be associated with the same volumes on magnetic media. For example, turning to FIG. 3, a block diagram is presented of an exemplary magnetic media storage device for a system to perform storage operations on electronic data in a computer network according to an embodiment of the invention. A magnetic media storage device 150, such as a hard disk, is shown. The magnetic media storage device 150 is divided into two volumes 155 and 160 which are associated with a first media agent 165 and a second media agent 170. Previously, each volume on a magnetic media storage device 150 maintained a static relationship with a given media agent 105. For example, if the first volume 155 was associated with the first media agent 165, then the second media agent 170 would only be able to conduct storage operations with the first volume 155 by passing any associated electronic data through the first media agent 165. The present invention, however, permits media agents 105 to share the same volume(s) on a given magnetic storage device. Thus, as further described herein, a first media agent 105 can perform, on a given magnetic media volume, storage operations on data associated with a first storage policy copy, and a second media agent can perform, on the same magnetic media volume, storage operations on different data associated with a second storage policy copy. For example, media agent 165 and 170 can both perform storage operations on the first volume 155 or the second volume 160. FIG. 4 presents a flow chart of a method for performing storage operations on electronic data in a computer network according to an embodiment of the invention. Selection of desired storage components for storage operations is performed dynamically. The system initiates a storage operation, step 175, in response to a scheduled procedure or as directed by a user. For example, the system might initiate a backup operation or a restore operation at a specific time of day or in response to a certain threshold being passed as specified in a storage policy. The system selects a media agent 105 according to selection logic further described herein, step 180. Some examples of selection logic include the ability to conduct a LAN-free storage operation, such as using a SAN, and the desire to optimize storage operations via load balancing. For example, an index entry in the storage manager 100 index cache 110 might associate certain media agents 105, storage devices 115, or other components with LAN-free storage operations either via user input, network topology detection algorithms known in the art, or other methods. As another example, the system might select a free media agent 105 to optimize storage operations via load balancing when a default media agent 105 or other media agent 105 specified in a storage policy is already performing other storage operations or otherwise occupied. The system also selects an appropriate drive pool in a network storage device according to selection logic further described herein, step 185. Once the system has selected an appropriate media agent and drive pool, the storage operation is performed, step 190 using the selected storage components. FIG. 5 presents a flow chart of a method to archive electronic data in a system to perform storage operations on electronic data in a computer network according to an embodiment of the invention. More specifically, FIG. 5 presents a method for dynamically selecting a drive pool according to an embodiment of the invention. The system makes a call to reserve one or more archive streams, step 195. Archive streams are generally data paths with permit storage operations to be performed in parallel on electronic data. An archive stream generally has a one-to-one correlation with a media group, such as a media agent 105 and storage device 115. Thus, according to one embodiment of the invention, the number of archive streams allowed on a storage policy is the sum of all drives in all available drive pools. For example, a system with three drive pools composed of ten total drives could reserve ten archive streams to copy data to each of the drives simultaneously thus increasing storage efficiency and achieving other useful goals. In one embodiment, the system uses the number of drives in a selected drive pool as the default number of streams to reserve. In an alternate embodiment, the system uses magnetic storage libraries as storage devices 115 instead of tape libraries containing drives. Here, the maximum number of streams would equal the number of readers and writers on all mount paths to the magnetic storage libraries. The system selects one or more appropriate storage locations for the data to be archived, step 200. In some embodiments, a resource manager module associated with the storage manager 100 selects the storage location(s). For example, a resource manager determines the appropriate storage device 115, media agent 105, and drive pool combination based on the pool of available storage network components and other criteria. Additional criteria used in the selection process generally consider improving efficiency of the storage operation to be performed. Load balancing, for example, is one exemplary consideration. The system may contain a given number of drives, but some of those drives may be used by other jobs and thus unavailable. The system thus selects from among available drives as one selection criterion. Alternatively, the network path to a particular storage component may be experiencing heavy traffic and thus a less trafficked path offering greater bandwidth may be selected as desirable. Another exemplary selection criterion is whether selection of a given drive or set of drives would enable LAN-free or auxiliary archiving. For example, in a given network, certain drives might be accessible via a SAN or other alternate storage route which would reduce the network traffic caused by an archiving operation. Preference, is thus given to selection of these drives over drives which would instead increase the network load. Yet another exemplary selection criterion is in the case of a storage component failover situation. For example, where an entire media agent 105 or storage device 115 as a whole is offline or if a certain number of drives in a storage device are offline, then the system, in some embodiments, dynamically selects an alternate media agent 105 or drive pool to perform storage operations. In some embodiments, the alternate media agent 105 or drive pool in the case of failover is specified according to preferences associated with a storage policy. For example, a storage policy may contain a list of failover candidates or selection logic, as described herein, for selecting a storage location to serve as a failover candidate. In some embodiments, the failover candidates are expressed as a triplet indicating the media agent 105, the storage device 115, and, provided the storage device is not a magnetic media storage device 150, the drive pool. Thus, the triplet “LIB1/MA2/DP1” might be used to represent a failover candidate storage path using media agent 115 MA2, storage device 115 LIB1, and drive pool DP1. In other embodiments, a user specifies the alternate storage device 115, media agent 105, or drive pool directly. The system reserves the selected storage candidates, step 205, and returns the storage IDs of successful reservations to the storage manager 100, step 210. In some embodiments, the storage IDs are unique identifiers enabling components of the system to identify and communicate with the storage candidates. For example, in some embodiments, the storage IDs comprise a unique component name coupled with a network path such as a Uniform Naming Convention (“UNC”) entry. The storage IDs of the successful reservations are used to update a media group table stored in the storage manager 100 index cache 110 or other similar locations accessible to components of the system, step 215. The reserved components are thus accessible to other components of the system to perform the archive operation or other storage operations. FIG. 6 presents a flow chart of a method to restore or auxiliary copy electronic data in a system to perform storage operations on electronic data in a computer network according to an embodiment of the invention. A restore or auxiliary copy operation is initiated and the electronic data to be restored or copied is identified, step 220. The system locates the media on which the electronic data to be restored or copied is stored, step 225. Thus, index data stored at the storage manager 100, a media agent 105, or another location is consulted to determine the media ID where the archive file of the electronic data starts. In some embodiments, the system consults a slot map table contained in the index cache 110 to determine the media ID where the archive file of the electronic data starts. The system determines the library/media agent/drive pool combination for the source tape storing the electronic data being restored or copied, step 230. Alternatively, the system determines the library/media agent/magnetic storage media volume combination for the electronic data being restored or copied. As previously described, in some embodiments the system determines the media agent 105 according to user preferences, selection logic for increasing network efficiency, or other factors. For example, if the electronic data to be restored or copied is located on a particular tape 140 in a given storage device 115, there may be a finite set of media agents 105 that are associated with the storage device 115 due to network pathways, component failures, user preferences, or other reasons. The system establishes a network connection to the selected media agent 105 and other components, step 235. In some embodiments, the system establishes a high speed connection, such as a DataPipe™ connection manufactured by CommVault Systems, and further described in U.S. Pat. No. 6,418,478 which is hereby incorporated herein by reference in its entirety. Electronic data is thus transferred over the established connection from the storage device 115 to its intended destination such as a network client 85, an information store 90, or other network component, step 240. In some embodiments, the entire archive file is generally created by a single attempt of backup and is contained within and accessible to the same media agent 105. Thus, a media agent 105 is identified only when initially opening the archive file. When media spanning occurs in the middle of the archive file, however, such as in the case of a file spanning multiple tapes 140 or volumes, the subsequent pieces of media containing the remaining electronic data must be located and requested, step 245. In the case of media spanning, control thus returns to step 225 to locate the additional media and continue the storage operation. In some embodiments, the initially selected media agent 105 is first queried to determine whether it is associated with the additional media, and if so, to continue the storage operation. If the initially selected media agent 105 is not associated with the additional media, the system queries the other media agents 105 in the network and attempts to locate the additional media. For example, the system may search index caches 110 associated with the system media agents 105 to locate the additional media. Alternatively, if the system cannot locate the additional media, the user is prompted to manually import or otherwise make available the media holding the additional electronic data required to complete the storage operation. FIG. 7 presents a flow chart of a method to restore a storage index in a system to perform storage operations on electronic data in a computer network according to an embodiment of the invention. In larger storage networks, scalability problems sometimes occasion the loss of index cache 110 directories from media agents 105. For example, in a network with many media agents 105 and a great deal of storage operations being performed, media agents 105 may load and unload different index caches 110 depending on the electronic data subject to the storage operations being performed. Such loss of an index cache 110 directory from the memory of a media agent 105 requires that the index cache 110 directory be reloaded from stored media such as tapes 140 in a storage device. Reloading an index in this manner, however, often places strain on the network drives, and also results in high system resource usage through the instantiation of related processes and threads such as, for example, ifind, createindex, pipelines, and other actions. For example, when a media agent 105 performs a storage operation, the media agent index cache 110 is updated using a createindex process to indicate any new network pathways, changes to the files system, version information, and other information useful in performing storage operations. The index cache 110 directory must first be restored before the createindex process can be run to reflect these changes. The present invention, thus provides, in some embodiments, a method for efficiently restoring an index cache 110 directory. The system determines whether there is an index in the cache 110 of a selected media agent, step 255. The system may query media agents 105 directly to determine if there is a copy of the index in a local cache 110. Alternatively, the system may look for the index in other locations, such as in a shared index system as further described herein. If the index is not in the cache 110, then the system determines the media ID of the archive file containing the index by consulting reference tables stored in the media agent 105 or the storage manager 100 index cache 110, step 260. These tables identify the location of the index file and identify the actual storage media holding the index file such as a particular tape 140, volume 155, or other storage media. In the case of a tape 140 or other similar removable storage media, the system reserves a drive for accessing the media, step 265, and performs a storage operation to restore the index to the local cache 110 of the selected media agent 105, step 270. In some embodiments, such as in the case of multiple media agents 105 having access to the index, preference is given to a LAN-free or otherwise preferred media agent 105. This is advantageous in the case of backups since the createindex has a high chance of being on the same machine as the tail of the pipeline. Once the system determines that the index is in the local cache 110 of the selected media agent 105, the index is updated or otherwise accessed, such as through a createindex process, to perform the storage operation at hand, step 275. The storage group table is updated to reflect the storage operations performed, step 280. In some embodiments, the system employs a shared index cache 110 location. A shared index might be employed, for example, to make the index available to all media agents 105 that may need to participate in a storage operation. Multiple media agents 105, for example, might be candidates for load balancing or failover operations, and all need access to the network path of the index so that the index will be available to each of them. Otherwise, extra index restores would be required when different media agents 105 were used for subsequent storage operations. Thus, in some embodiments, the index cache location is indicated by a UNC path universally accessible via a username and password. Each media agent 105 is also associated with a unique username and password that permit component authentication, access control, and other similar functions. The username, password, and UNC path to the shared index location is stored in memory associated with each media agent 105. In some embodiments, an indexing module of the media agent 105 employs user impersonation before accessing the index cache. In an alternate embodiment, the system employs a shared index cache 110 in which a pool of network UNC paths is designated for each media agent 105 as a secondary storage area for the index. At the end of each backup, a media agent 105 copies the index to this secondary area which is accessible to all media agents 105 in the pool. Thus, when a media agent 105 requires the index, the media agent 105 queries both its local cache 110 and the pool of UNC paths to locate the correct index. If the index is located in the secondary area and not in the local cache 105, then the index is copied to the local area for immediate use. Upon completion of a storage operation, such as a backup or a restore, the index is copied back to the shared area so that other media agents 105 and processes can access the index. In some embodiments, the system determines which media agent 105, for a given browse of a client 85 at a point in time, is most likely to already to have a useable index version already in its local cache 110. For example, in some embodiments, the storage manager 100 tracks which media agent 105 performed the last storage operation for a particular client 85. A media agent 105 is selected for a client 85 browse at time T such that the last backup in the full backup cycle at time>=T was done with indexing at that media agent 105. FIG. 8 presents a flow diagram showing how dynamic volume sharing is accomplished according to one embodiment of the invention. A client application or other application initiates a request to the storage manager 100 to perform a storage operation on electronic data on a storage device 115, such as a magnetic media storage device 150, in the network, and the storage manager 100 processes this request by requesting access to the volume on which the data is storage, step 285. When a client computer 85 is configured, client data that is to be subject to storage operations is associated with a particular media agent 115. When that client data is stored or retrieved in the future, the client computer 85 passes storage operation requests on to the associated media agent 115. The media agent 115 associates this client data with a particular storage media, such as a volume on a magnetic media storage device 150. Using dynamic volume sharing, one or more media agents can store and retrieve data among multiple volumes spanning multiple magnetic media storage devices 150. When the media sharing request is received, the storage manager 100 verifies that a storage device 115 is available that can be switched to accommodate the request, step 290. The storage manager 100 tracks storage device 115 availability in the storage manager index cache 110 populated with information regarding available storage devices 115 and their respective media agent 105 controllers. Access paths across the network to media agents 105 and then on to appurtenant storage devices 115 are also stored in the storage manager index cache 110. Upon identifying an appropriate storage device 115, the storage manager 100 directs the media agent 105 controlling the storage device 115 to go into a deactivated state with respect to that storage device, step 295. Even though, in some embodiments, there are multiple media agents executing on various hosts for the same storage device 115, the relationship is static and only one of them can control a storage device 115 at a given instant. The other media agents 105 are said to be in a deactivated state with respect to that storage device 115. The deactivated media agents 105 run a listening process waiting for a message from the storage manager 100 directing them to become active with respect to a storage device 115. Once the first media agent 105 has been deactivated with respect to the storage device 115, the storage manager communicates to the listening process of a second media agent 105 on which the storage device 115 will be mounted to change from a deactivated state to an activated state with respect to the storage device 115, step 300. At this point the storage manger 100 also updates the storage manager cache 110 to reflect that control of the storage device 115 has been shifted from the first media agent 105 to the second media agent 105, and that the first media agent is now deactivated and that the second media agent is now activated with respect to that storage device, step 305. The second media agent 105 communicates with the storage device 115 and executes procedures necessary to mount storage device 115 and any associated volumes to the second media agent, step 310. In some embodiments, the second media agent 105 mounts one or more of the volumes associated with the storage device 115, and volumes in the same storage device 115 not mounted by the second media agent 105 may be mounted or otherwise associated with other media agents 105. Once the mount is performed the storage device 150 and its associated volumes 150 are logically connected to the second media agent 105, and this access path is stored by the second media agent 105 in its index cache 110, step 315. The media agent 105 stores the access path to the storage device 115 in the media agent index cache 110 because a storage device 115 connected to multiple media agents 105 may have multiple access paths. Mounting the storage device 115 to the media agent 105 and the resultant access path produced is in large part related to the hardware configuration of the media agent 105. The media agent 105 is generally best-suited to store and delegate management of the access path to the storage device that it controls. In some alternate embodiments, the storage manager 100 stores and tracks the individual hardware configuration of all the network media agents 105 in the storage manager index cache 110 and then passes the resultant access paths to the network storage devices 115 on to the media agents 105 when necessary. In other embodiments, media agent 105 hardware configurations and resultant access paths to the network storage devices 115 are stored in a shared index location as further described herein. Once the media agent 105 has completed the mount of the storage device 115 (and any associated volumes) and stored the access path to the storage device 115 in its own media agent index cache 110 or other location, then the access path to the storage device 115 is returned by the media agent 105 to the storage manager 100 where it is also stored in the storage manager index cache 110 for future recall, step 320. While media agents 115 generally communicate with storage devices 115 and the storage manager 100, the storage manager 100 generally communicates with client applications. In some embodiments, the storage manager 100 returns the storage device access path to a client application or other application and initiates a storage operation as appropriate, step 325. Systems and modules described herein may comprise software, firmware, hardware, or any combination(s) of software, firmware, or hardware suitable for the purposes described herein. Software and other modules may reside on servers, workstations, personal computers, computerized tablets, PDAs, and other devices suitable for the purposes described herein. Software and other modules may be accessible via local memory, via a network, via a browser or other application in an ASP context, or via other means suitable for the purposes described herein. Data structures described herein may comprise computer files, variables, programming arrays, programming structures, or any electronic information storage schemes or methods, or any combinations thereof, suitable for the purposes described herein. User interface elements described herein may comprise elements from graphical user interfaces, command line interfaces, and other interfaces suitable for the purposes described herein. Screenshots presented and described herein can be displayed differently as known in the art to input, access, change, manipulate, modify, alter, and work with information. While the invention has been described and illustrated in connection with preferred embodiments, many variations and modifications as will be evident to those skilled in this art may be made without departing from the spirit and scope of the invention, and the invention is thus not to be limited to the precise details of methodology or construction set forth above as such variations and modification are intended to be included within the scope of the invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>The invention disclosed herein relates generally to performing storage operations on electronic data in a computer network. More particularly, the present invention relates to selecting, in response to the initiation of a storage operation and according to selection logic, a media management component and a network storage device to perform storage operations on electronic data. Storage of electronic data has evolved through many forms. During the early development of the computer, storage of this data was limited to individual computers. Electronic data was stored in the Random Access Memory (RAM) or some other storage medium such as a hard drive or tape drive that was an actual part of the individual computer. Later, with the advent of networked computing, storage of electronic data gradually migrated from the individual computer to stand-alone storage devices accessible via a network. These individual network storage devices soon evolved in the form of networkable tape drives, optical libraries, Redundant Arrays of Inexpensive Disks (RAID), CD-ROM jukeboxes, and other devices. Common architectures included drive pools, which generally are logical collections of drives with associated media groups including the tapes or other storage media used by a given drive pool. Serial, parallel, Small Computer System Interface (SCSI), or other cables, directly connected these stand-alone storage devices to individual computers that were part of a network of other computers such as a Local Area Network (LAN) or a Wide Area Network (WAN). Each individual computer on the network controlled the storage devices that were physically attached to that computer and could also access the storage devices of the other network computers to perform backups, transaction processing, file sharing, and other storage-related operations. Network Attached Storage (NAS) is another storage scheme using stand-alone storage devices in a LAN or other such network. In NAS, a storage controller computer still “owns” the storage device to the exclusion of other computers on the network, but the SCSI or other cabling directly connecting that storage device to the individual controller or owner computer is eliminated. Instead, storage devices are directly attached to the network itself. Yet another network storage scheme is modular storage architecture which is more fully described in application Ser. No. 09/610,738 and application Ser. No. 09/744,268. An example of such a software application is the Galaxy™ system, by CommVault Systems of Oceanport, N.J. The Galaxy™ system is a multi-tiered storage management solution which includes, among other components, a storage manager, one or more media agents, and one or more storage devices. The storage manager directs storage operations of client data to storage devices such magnetic and optical media libraries. Media agents are storage controller computers that serve as intermediary devices managing the flow of data from client information stores to individual storage devices. Each storage device is uniquely associated with a particular media agent and this association is tracked by the storage manager. A common feature shared by all of the above-described network architectures is the static relationship between storage controller computers and storage devices. In these traditional network architectures, storage devices can each only be connected, virtually or physically, to a single storage controller computer. Only the storage controller computer to which a particular device is physically connected has read/write access to that device. A drive pool and its associated media group, for example, can only be controlled by the computer to which it is directly connected. Therefore, all backup from other storage controller computers needs to be sent via the network before it can be stored on the storage device connected to the first storage controller computer. At times, storage solutions in some of the above-described network architectures including LAN, NAS, and modular storage systems may cause overloading of network traffic during certain operations associated with use of storage devices on the network. The network cable has a limited amount of bandwidth that must be shared among all the computers on the network. The capacity of most LAN or network cabling is measured in megabits per second (mbps) with 10 mbps and 100mbps being standard. During common operations such as system backups, transaction processing, file copies, and other similar operations, network traffic often becomes overloaded as hundreds of megabytes (MB) and gigabytes (GB) of information are sent over the network to the associated storage devices. The capacity of the network computers to stream data over the network to the associated storage devices in this manner is greater than the bandwidth capacity of the cabling itself so ordinary network activity and communication slows to a crawl. As long as the storage devices are attached to the LAN or other network, this bandwidth issue remains a problem. The Storage Area Network (SAN) is a highly-evolved network architecture designed to facilitate transport of electronic data and address this bandwidth issue. SAN architecture requires at least two networks. First, there is the traditional network described above which is typically a LAN or other such network designed to transport ordinary traffic between network computers. Then, there is the SAN itself which is a second network that is attached to the servers of the first network. The SAN is a separate network generally reserved for bandwidth-intensive operations such as backups, transaction processing, and the like also described above. The cabling used in the SAN is usually of much higher bandwidth capacity than that used in the first network such as the LAN and the communication protocols used over the SAN cabling are optimized for bandwidth-intensive traffic. Most importantly, the storage devices used by the network computers for the bandwidth-intensive operations are attached to the SAN rather than the LAN. Thus, when the bandwidth-intensive operations are required, they take place over the SAN and the LAN remains unaffected. CommVault's proprietary DataPipe™ mechanism further described in U.S. Pat. No. 6,418,478 is used with a SAN to further reduce bandwidth constraints. The DataPipe™ is the transport protocol used to facilitate and optimize electronic data transfers taking place over a Storage Area Network (SAN) as opposed to those taking place over a LAN using NAS. None of these solutions, however, address the static relationship between individual storage controller computers and individual storage devices. LANs, WANs, and even SANs using a DataPipe™ all require a static relationship between storage controller computer and storage device since each storage device on the network is uniquely owned by a storage controller computer. As discussed, when a storage device in this traditional architecture is assigned to a storage controller computer, that storage controller computer owns the device indefinitely and to the exclusion of other computers on the network. This is also true with both logical and physical storage volumes. One computer cannot control the drive pool and media group being that is controlled by another. Requests to store and retrieve data from such a drive pool and media group would have to first pass through the controlling computer. Such a static relationship between storage controller computer and storage device often leads to an inefficient use of resources. For example, if each storage controller computer needs access to two storage devices and there are five storage controller computers in the network, then a total of ten storage devices will be required. The actual amount of work each of the ten storage devices performs might be much less than the workload capacity of each storage device. Such underutilization of storage device resources cannot be solved when a static relationship is required between storage device and storage controller computer. If the static relationship were dynamic, however, and storage controller computers could actually share devices, then this underutilization can be addressed. Assuming in the above example that each of the five storage controller computers only uses ten percent of each device's workload capacity, then if all the storage controller computers could actually share the same two storage devices, eight of the storage devices could be eliminated without loss of performance or capability. Furthermore, none of these existing solutions provide access to storage devices in the event of a storage controller failure. For example, if a storage controller computer were unavailable due to a hardware or software malfunction, then other computers on the network would not be able to access data stored on any storage device associated with the storage controller computer. Until the storage controller computer was brought back online, the data contained on any associated storage device would be effectively unrecoverable. If the association between the storage controller computer and a storage device were not static, however, then another storage controller computer could bypass the unavailable storage controller computer and access the storage device to retrieve the data. There is thus also a need for a system which enables dynamic association of storage controller computers and storage devices | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention addresses, among other things, the problems discussed above performing storage operations on electronic data in a computer network. In accordance with some aspects of the present invention, computerized methods are provided for dynamically selecting media agents and storage devices to perform storage operations on data. The system selects, in response to the initiation of a storage operation and according to a first set of selection logic, a media management component to manage the storage operation. The system also selects, in response to the initiation of the storage operation and according to a second set of selection logic, a network storage device to associate with the storage operation. Using the selected media management component and the selected network storage device, the system performs the storage operation on the data. In another embodiment, the system provides a method for sharing a magnetic media volume in a network. The system, in response to a volume sharing request, removes an association between a first media management component and the magnetic media volume. For example, in some embodiments, the system removes an index entry associating a first media management component and the magnetic media volume. In response to a volume sharing request and according to a set of selection logic, the system associates a second media management component with the magnetic media volume. For example, in some embodiments the system creates an index entry associating the second media management component and the magnetic media volume. In other embodiments, the system mounts the magnetic media volume to the second media management component. | 20040405 | 20070717 | 20050224 | 93715.0 | 1 | ELMORE, STEPHEN C | SYSTEM AND METHOD FOR DYNAMICALLY PERFORMING STORAGE OPERATIONS IN A COMPUTER NETWORK | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,818,839 | ACCEPTED | Two tier brazing for joining copper tubes to manifolds | A brazing process for joining copper and copper alloy tubes to a fitting which includes first forming a layer of a high melting temperature noble metal on one end of a copper or copper alloy tube. The plated end is then brazed to a metal ferrule to form a copper alloy-ferrule assembly. The assembly is then furnace brazed to a metal fitting. | 1. A two tier brazing process for joining a tube to a fitting which comprises: (a) forming a layer of a noble metal on at least one end of a copper or copper alloy tube; (b) brazing said end to a metal ferrule to form a copper alloy-ferrule assembly; and (c) furnace brazing said assembly to a metal fitting. 2. The process of claim 1 in which the brazing step of (b) utilizes a focused heat source. 3. The process of claim 1 in which the metal ferrule contains a layer of a high melting temperature noble metal on at least a portion of its outer surface. 4. The process of claim 1 in which the noble metal layer is selected from the group consisting of nickel, palladium, platinum, iridium, cobalt and osmium. 5. The process of claim 1 in which the ferrule is made of a metal alloy selected from the group consisting of austenitic stainless steel, monel and alloys of cobalt. 6. The process of claim 1 in which the focused heat source is an induction coil. 7. The process of claim 1 in which the focused heat source uses electromagnetic radiation. 8. The process of claim 1 in which the brazing filler system includes at least one of the group consisting of silver, copper, gold, nickel and mixtures and alloys thereof. 9. The process of claim 1 in which the furnace brazing is carried out in a vacuum furnace. 10. The process of claim 1 in which the furnace brazing is carried out in a retort furnace. 11. A two tier brazing process for joining copper alloy tubes to a manifold which comprises: (a) plating a layer of a high melting temperature noble metal on at least one end of a copper alloy tube; (b) brazing said plated end to a metal ferrule utilizing a focused heat source to form a copper alloy-ferrule assembly; and (c) furnace brazing said assembly into a metal manifold. 12. The process of claim 11 in which the metal ferrule contains a layer of a high temperature noble metal on at least a portion of its outer surface. 13. The process of claim 11 in which the plated layer comprises nickel. 14. A two tier brazing process for joining copper and copper alloy tubes to manifolds which comprises: (a) forming a layer of nickel on at least one end of a copper or copper alloy tube; (b) brazing said plated end to a metal ferrule utilizing a focused heat source to form a copper alloy-ferrule assembly, and where said ferrule is made of a metal selected from the group consisting of austenitic stainless steel, monel and an alloy of cobalt; and (c) furnace brazing said assembly into a metal manifold. 15. The process of claim 14 in which the nickel layer is formed on said tube by electroplating. 16. A copper alloy-ferrule assembly suitable for use in being joined by brazing to a metal manifold which comprises a copper or copper alloy tube having a plating of a high melting temperature noble metal on at least one end thereof and a metal ferrule brazed to the plated end of said tube, with at least a portion of the outer surface of said ferrule having a plating of a high melting temperature noble metal thereon. 17. The assembly of claim 16 in which the plated metal is nickel. 18. The assembly of claim 16 in which the ferrule is made of a metal alloy consisting of stainless steel, monel and cobalt. | FIELD OF THE INVENTION The invention relates in general to joining copper or copper alloy tubes to metallic tubes such as manifolds, and more specifically to a two step brazing method for joining such tubes and manifolds. BACKGROUND OF THE INVENTION The conventional method of furnace brazing copper tubes directly to metal manifolds in a vacuum braze furnace has long presented problems with respect to alloying and erosion. Since vacuum braze furnaces do not allow for any significant observation of the braze joint during heating and additionally must cool a significant mass of tooling and equipment from the brazing temperature, the braze cycle cannot be terminated the moment the braze melts and fills the joint. Therefore to account for variables such as the measurement uncertainty of the thermocouples used measure the temperature of the part, and the variability of the amount of time and superheat required to fill the braze joints, the degree of alloying will always be expected to be higher than that involved in focused heating source methods. These conditions very often lead to the interaction of copper alloy tubes with braze filler resulting in changes the microstructure of the copper, which generally reduces its strength, ductility and thermal conductivity. The equation describing the rate at which a brazing filler metal can dissolve and remove a base metal is governed by the well-known ahrrenius-type equation: Rate of Dissolution=K1·exp [−Q/k2T] The equation above identifies the three variables influencing base metal dissolution and related phenomenon (alloying and erosion). Activation energy (represented by Q) is a function of the material combination present (brazing filler metal and base metal combination). K1 and k2 are constants determined by the materials present. The second variable influencing the rate of dissolution of the copper alloy tubing by the brazing filler metal is temperature or superheat (represented by T). Superheat is controlled by the joining process heat source. As shown by the equation, the rate of base metal dissolution by a braze filler increase exponentially with the superheat. Therefore an ideal brazing process for joining copper tubes to metal manifolds is one which minimizes the superheat required to draw the brazing filler metal into the braze joint by capillary action. In the case of induction or radiant heating methods, the braze filler can be observed directly as it melts and flows into the joint. This allows the braze cycle (and continued heating with attendant increases in superheat) to be terminated the moment a sound braze joint has been achieved. By contrast, furnace brazing as stated above, requires the tubes to be directly brazed to the manifolds in a vacuum braze furnace which does not allow for visual monitoring of the braze joint during heating, the braze cycle (and thus continued heating) cannot therefore be terminated the moment the braze metals and fills the joint. These conditions therefore usually result in a greater amount of superheat than that involved in focused heating source methods. A third variable that is implied but not mentioned by the equation is time. For a given rate of dissolution, the extent of dissolution is impacted by the product of the rate and the time. Therefore an ideal brazing process for the application under consideration by the present invention is one which minimizes the time the braze filler is molten. Focused heating sources satisfy this rapid quenching of the braze joint from the brazing temperature simply by shutting off the heat source. The induction braze cycle typically lasts less than about two minutes. In contrast, the alternate furnace braze cycle lasts approximately 250 minutes. This over two orders of magnitude difference in the overall braze cycle reduces the amount of time the copper alloy tubes are exposed to molten braze filler and dramatically reduces the amount of superheat exposure. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a brazing method which overcomes the problems of the conventional methods described above. It is a further object of the present invention to provide an improved method for joining copper tubes to manifolds. It is another object of the present invention to provide a two step brazing process which allows copper tubes to be efficiently joined to a metal manifold. It is another object of the present invention to provide a copper tube ferrule assembly which facilitates joining copper tubes to metal tubes such as manifolds. It is yet another object of the present invention to provide an improved method of brazing copper tube-ferrule assembly to a metal manifold. The invention is directed to a method for metallurgically joining copper or copper alloy tubing to metallic manifolds for combustion chamber applications. This objective is accomplished through a three step process. Copper or copper alloy tubes are coated or plated with a noble metal. The plated copper alloy tubing is then brazed to a metal ferrule to form a copper alloy tube-ferrule assembly. The copper alloy ferrule assembly is then brazed into a fitting or metallic tube such as a manifold. Depending on the chemistry of the brazing filler metal ferrule and manifold materials, brazing atmosphere quality, and brazing temperature, plating of the faying surfaces may or may not be required to facilitate wetting of the ferrule or manifold material by the braze filler selected. The concept of using a two tiered brazing sequence to join the copper alloy tubes to metallic manifolds, with the first tier being a brazing process involving a focused heat source is an improvement over conventional techniques described above which are susceptible to the harmful effects of alloying and erosion. BRIEF DESCRIPTION OF THE DRAWINGS For a further understanding of these and objects of the invention, reference will be made to the following detailed description of the invention which is to be read in connection with the accompanying drawing, where: FIG. 1 is a side sectional view of a copper or copper alloy tube having a layer of a noble metal on one end thereof. FIG. 2 is a side sectional view of a ferrule having a layer of a noble metal on one end thereof. FIG. 3 is a side sectional view of the ferrule of FIG. 2 in engagement with the end of the copper tube of FIG. 1 for brazing to form a copper tube-ferrule assembly. FIG. 4 is a side sectional view of the brazed assembly of FIG. 3 in position for attachment by brazing to a metal manifold. FIG. 5 is a side sectional view of a copper or copper alloy tube having a layer of a noble metal on its outer surface. FIG. 6 is a side sectional view of the tube of FIG. 6 brazed to a metal manifold. DETAILED DESCRIPTION OF THE INVENTION The process of the present invention provides significant improvement over the conventional technique described in FIGS. 5 and 6 of the drawings. Conventional methods involve providing a copper or copper alloy tube 10 and plating or coating the entire length of the tube with the noble metal 12. The coated or plated copper tube is then brazed directly to a manifold 40 as illustrated in FIG. 6. Typical problems associated with this technique occur where the plating over the entire surface of the copper tube is not uniform. When this occurs, a high risk of failure results due to imperfections in the plating or coating surface resulting in the brazing material alloying with the copper tube and deleteriously effecting the mechanical and physical properties of the copper tubes. Through the use of the present invention, the ferrule part of the copper tube-ferrule assembly can be brazed effectively to a compatible alloy or metal of the manifold, and therefore avoid the problems associated with coating the entire length of the copper tube with a noble metal. FIGS. 1-4 illustrate one possible embodiment of the process of the present invention. In FIG. 1 a copper or copper alloy tube 10 is coated or plated with a high melting temperature metal 12 which is sufficiently noble to allow for the reduction or disassociation of its oxide in an inert atmosphere at temperatures required for brazing. Suitable materials include nickel, palladium, platinum, iridium, cobalt and osmium. Tube 10 may be substantially pure copper or a copper alloy. Suitable copper alloys which may be used typically contain aluminum in a concentration of about 0.2% by weight. In a preferred embodiment, the outer coating may comprise an electroplated layer of nickel approximately 10% of the wall thickness of the copper or copper alloy tube. A metal ferrule or cap 14 as illustrated in FIG. 2 is provided, and in one embodiment has a layer of a noble metal 12 coated or plated over a portion of its upper surface. The metal ferrule must be suitable for brazing and attachment to a metal manifold and may be made from austenitic stainless steel, monel or a cobalt alloy having a thermal expansion which is compatible with the tube and manifold. The ferrule 14 is adapted for fitting contact and placement over the plated end of the copper tube as illustrated in FIG. 3 to form a copper tube-ferrule assembly. In a first tier of the process, brazing perform 18 is positioned as shown in FIG. 3 for forming a brazed joint between the ferrule and copper tube in the brazed contact area as illustrated by the brackets in FIG. 3. Suitable braze filler systems which may be used in the present invention include silver, copper, gold and nickel base systems. Specific systems which may be used include the following: Cu—Ge—Ni Au—Ag—Cu Au—Cu—Ni Ag Au—Cu Ag—Cu—Pd Ag—Cu A suitable system for the first tier brazing includes 80% Au-20% Cu. The following brazing parameters have been found to be suitable for use in the present invention: 1st tier braze process: induction braze at 1670 to 1900 F for 5 to 90 seconds using 200 kHz and single turn water cooled induction coil; brazing performed under positive pressure of argon with dew point of −35 F or better. The ferrule alloy must be selected to have a thermal expansion that is compatible with that of the copper or copper alloy being used for the tube. In the present invention the heating method used for first tier brazing must be selected to allow the thermal gradients within the part to be engineered to provide repeatable melting and flow of the brazed filler into the brazed joint or area. It has been found that a localized heat source is preferred to accomplish this objective. Suitable localized heat sources include induction coils and electromagnetic radiation sources. The copper tube and ferrule as shown in FIG. 3 are brazed with the heat source to form a copper alloy-ferrule assembly. In a second tier of the process, a plurality of assemblies are then brazed into a metallic manifold 30 as illustrated in FIG. 4 using brazed perform 32, preferably in an isothermal braze environment such as a vacuum furnace. For second tier brazing a 60% Ag, 30% Cu, 10% Pd system has been found to be suitable, with a furnace braze at 1585 to 1615 F for 15 to 45 minutes; brazing performed under an inert gas (helium or argon). Depending upon the chemistry of the ferrule and the manifold materials, the brazing atmosphere quality, and brazing temperature, plating of the faying surfaces may or may not be required to facilitate wetting of the ferrule and manifold material by the braze filler selected. The process of the present inventions allows for the effective joining of copper and copper alloy tubes to a manifold to obtain the advantages of the thermal conductivity of copper while effectively and efficiently joining the copper tubes to a high temperature alloy manifold through the copper alloy-ferrule assembly of the present invention. One possible use of such tube-ferrule-manifold assembly is in a combustion chamber of a rocket motor. While the present invention has been particularly shown and described with reference to the preferred mode as illustrated in the drawing, it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the invention as defined by the claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>The conventional method of furnace brazing copper tubes directly to metal manifolds in a vacuum braze furnace has long presented problems with respect to alloying and erosion. Since vacuum braze furnaces do not allow for any significant observation of the braze joint during heating and additionally must cool a significant mass of tooling and equipment from the brazing temperature, the braze cycle cannot be terminated the moment the braze melts and fills the joint. Therefore to account for variables such as the measurement uncertainty of the thermocouples used measure the temperature of the part, and the variability of the amount of time and superheat required to fill the braze joints, the degree of alloying will always be expected to be higher than that involved in focused heating source methods. These conditions very often lead to the interaction of copper alloy tubes with braze filler resulting in changes the microstructure of the copper, which generally reduces its strength, ductility and thermal conductivity. The equation describing the rate at which a brazing filler metal can dissolve and remove a base metal is governed by the well-known ahrrenius-type equation: in-line-formulae description="In-line Formulae" end="lead"? Rate of Dissolution= K 1 ·exp [− Q/k 2 T] in-line-formulae description="In-line Formulae" end="tail"? The equation above identifies the three variables influencing base metal dissolution and related phenomenon (alloying and erosion). Activation energy (represented by Q) is a function of the material combination present (brazing filler metal and base metal combination). K 1 and k 2 are constants determined by the materials present. The second variable influencing the rate of dissolution of the copper alloy tubing by the brazing filler metal is temperature or superheat (represented by T). Superheat is controlled by the joining process heat source. As shown by the equation, the rate of base metal dissolution by a braze filler increase exponentially with the superheat. Therefore an ideal brazing process for joining copper tubes to metal manifolds is one which minimizes the superheat required to draw the brazing filler metal into the braze joint by capillary action. In the case of induction or radiant heating methods, the braze filler can be observed directly as it melts and flows into the joint. This allows the braze cycle (and continued heating with attendant increases in superheat) to be terminated the moment a sound braze joint has been achieved. By contrast, furnace brazing as stated above, requires the tubes to be directly brazed to the manifolds in a vacuum braze furnace which does not allow for visual monitoring of the braze joint during heating, the braze cycle (and thus continued heating) cannot therefore be terminated the moment the braze metals and fills the joint. These conditions therefore usually result in a greater amount of superheat than that involved in focused heating source methods. A third variable that is implied but not mentioned by the equation is time. For a given rate of dissolution, the extent of dissolution is impacted by the product of the rate and the time. Therefore an ideal brazing process for the application under consideration by the present invention is one which minimizes the time the braze filler is molten. Focused heating sources satisfy this rapid quenching of the braze joint from the brazing temperature simply by shutting off the heat source. The induction braze cycle typically lasts less than about two minutes. In contrast, the alternate furnace braze cycle lasts approximately 250 minutes. This over two orders of magnitude difference in the overall braze cycle reduces the amount of time the copper alloy tubes are exposed to molten braze filler and dramatically reduces the amount of superheat exposure. | <SOH> SUMMARY OF THE INVENTION <EOH>It is therefore an object of the present invention to provide a brazing method which overcomes the problems of the conventional methods described above. It is a further object of the present invention to provide an improved method for joining copper tubes to manifolds. It is another object of the present invention to provide a two step brazing process which allows copper tubes to be efficiently joined to a metal manifold. It is another object of the present invention to provide a copper tube ferrule assembly which facilitates joining copper tubes to metal tubes such as manifolds. It is yet another object of the present invention to provide an improved method of brazing copper tube-ferrule assembly to a metal manifold. The invention is directed to a method for metallurgically joining copper or copper alloy tubing to metallic manifolds for combustion chamber applications. This objective is accomplished through a three step process. Copper or copper alloy tubes are coated or plated with a noble metal. The plated copper alloy tubing is then brazed to a metal ferrule to form a copper alloy tube-ferrule assembly. The copper alloy ferrule assembly is then brazed into a fitting or metallic tube such as a manifold. Depending on the chemistry of the brazing filler metal ferrule and manifold materials, brazing atmosphere quality, and brazing temperature, plating of the faying surfaces may or may not be required to facilitate wetting of the ferrule or manifold material by the braze filler selected. The concept of using a two tiered brazing sequence to join the copper alloy tubes to metallic manifolds, with the first tier being a brazing process involving a focused heat source is an improvement over conventional techniques described above which are susceptible to the harmful effects of alloying and erosion. | 20040406 | 20071113 | 20051006 | 98647.0 | 0 | STONER, KILEY SHAWN | TWO TIER BRAZING FOR JOINING COPPER TUBES TO MANIFOLDS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,818,944 | ACCEPTED | Clean room food processing systems, methods and structures | Some food pathogens are not well controlled by lethality treatments followed by refrigeration. A food processing facility according to this invention reduces the likelihood that food pathogens will be able to enter the food processing facility, or spread should they be able to enter. The food processing facility is divided into a plurality of area, with different areas having different allowed actions that can be taken on the food product, different rules and/or procedures for persons who are allowed entry, and/or different levels of cleanliness. The food processing facility includes a plurality of separate rooms for processing the food product, each including separate food processing machines, air handling systems, drain systems and/or often-used supplies and tools. Different air pressures within different areas limit the possible movement of airborne food pathogens. Sanitizing stations are placed between various ones of the different areas. | 1. A method for reducing contamination by an undesirable micro-organism within a food processing facility that processes a food product, comprising: transporting a food product into one of a plurality of food processing rooms, each food processing room comprising a single food processing line comprising at least one food processing device and at least one food packaging device; processing the food product in that food processing room; packaging the processed food product into a closed package in that food processing room such that any micro-organisms outside of the package will be unable to migrate into the interior of the package as long as the package remains closed; and transporting the closed package out of that food processing room. 2. The method of claim 1, further comprising applying a lethality treatment to the food product before transporting the food product into that food processing room, wherein transporting the food product into that food processing room comprises transporting the treated food product into that food processing room. 3. The method of claim 2, wherein: the food product comprises a processed meat product; and applying the lethality treatment to the processed meat product comprises at least one of: passing the processed meat product through a steam treatment; passing the processed meat product through a hot liquid bath, and passing the processed meat product through a radiant heat treatment, and passing the processed meat product through a chemical sanitizer. 4. The method of claim 3, wherein passing the processed meat product through a hot liquid bath comprises passing the processed meat product through an oil bath, or a water bath. 5. The method of claim 3, wherein passing the processed meat product through a radiant heat treatment comprises passing the processed meat product through at least one infra-red heating treatment. 6. The method of claim 2, wherein transporting the treated food product into that food processing room comprises: transporting the treated food product into a first area, at least that food processing room having a passage to the first area; and transporting the treated food product from the first area into that food processing room through the passage. 7. The method of claim 6, further comprising: having the first area at a first air pressure; maintaining that food processing room at an air pressure that is greater than the first air pressure; wherein transporting the treated food product from the first area into that food processing room comprises passing the treated food product through the passage from the first area into that food processing room while passing the ambient atmosphere through the passage from that food processing room into the first area. 8. The method of claim 7, wherein: applying the lethality treatment to the food product before transporting the food product into that food processing room comprises applying the lethality treatment in a treatment room; and transporting the treated food product into the first area comprises transporting the treated food product from the treatment room to the first area. 9. The method of claim 8, further comprising maintaining the treatment room at a second air pressure that is lower than the first air pressure, wherein transporting the treated food product from the treatment room to the first area comprises passing the treated food product through a passage from the treatment room into the first area while passing the ambient atmosphere through the passage from the first area into the treatment room. 10. The method of claim 9, wherein maintaining the treatment room at the second air pressure comprises exhausting the atmosphere in the treatment room to outside of the food processing facility at a rate that lowers the air pressure i the treatment room to a point below the first air pressure. 11. The method of claim 7, wherein maintaining that food processing room at an air pressure that is greater than the first air pressure comprises supplying air into that food processing room at a rate that increases the air pressure in that food processing room to a point that is above the first air pressure. 12. The method of claim 6, further comprising maintaining at least that food processing room and the first area at a first level of cleanliness when transporting the treated food product into the first area and when transporting the treated food product from the first area into that food processing room. 13. The method of claim 12, wherein maintaining at least that food processing room and the first area at the first level of cleanliness when transporting the treated food product into the first area and when transporting the treated food product from the first area into that food processing room comprises at least one of: limiting access to at least that food processing room and the first area to persons having at least a first predetermined level of food safety training; requiring persons entering at least one of that food processing room or the first area to wear a clean first-type set of clothing; and requiring persons entering at least one of that food processing room or the first area to undergo a first cleaning procedure prior to entering the first area. 14. The method of claim 6, wherein transporting the treated food product into that food processing room further comprises passing the treated food product through a chilling device that chills at least a surface region of the treated food product to a temperatures that is at most about a freezing point of the treated food product. 15. The method of claim 14, wherein transporting the treated food product from the first area into that food processing room through the passage comprises transporting the chilled treated food product into that food processing room through the passage. 16. The method of claim 2, wherein: applying the lethality treatment to the food product comprises applying the lethality treatment in a treatment room; and transporting the food product into that food processing room further comprises transporting the treated food product from the treatment room at least indirectly into that food processing room. 17. The method of claim 16, wherein transporting the treated food product at least indirectly into that food processing room further comprises passing the treated food product through a chilling device that chills at least a surface region of the treated food product to a temperatures that is at most about a freezing point of the treated food product before transporting the treated food product into that food processing room. 18. The method of claim 1, wherein transporting the food product into that food processing room comprises: holding the food product in a first area until the food product is to be processed in that food processing room; transporting the food product from the first area into a second area, at least that food processing room having a passage to the second area; and transporting the food product from the second area into that food processing room through the passage. 19. The method of claim 18, further comprising: maintaining the first area at a first level of cleanliness when holding the food product in the first area and when transporting the food product from the first area into the second area; maintaining at least that food processing room and the second area at least at a second level of cleanliness when transporting the food product from the first area into the second area and when transporting the food product from the second area into that food processing room. 20. The method of claim 19, wherein maintaining at least the first area at the first level of cleanliness when holding the food product in the first area and when transporting the food product from the first area into the second area comprises at least one of: requiring persons having entered at least the first area from a third area, where the third area is at a third level of cleanliness that is less than the first level of cleanliness, to wear at least a first-type set of clothing when in the first area; and requiring persons entering at least the first area from the third area to undergo a first cleaning procedure when passing from the third area into the first area. 21. The method of claim 20, wherein maintaining at least that food processing room and the second area at least at the second level of cleanliness when transporting the food product into the second area and when transporting the food product from the second area into that food processing room further comprises at least one of: limiting access to at least that food processing room and the second area to persons having at least a first predetermined level of food safety training; requiring persons entering at least one of that food processing room or the second area to enter from the first area; requiring persons entering at least one of that food processing room or the second area to wear a clean second-type set of clothing; and requiring persons entering at least one of that food processing room or the second area to undergo a second cleaning procedure when passing from the first area into at least one of that food processing room or the second area. 22. The method of claim 20, wherein maintaining at least the first area at the first level of cleanliness when holding the food product in the first area and when transporting the food product from the first area into the second area further comprises requiring persons leaving at least one of that food processing room or the second area to the first area to undergo a further cleaning procedure when passing from at least one of that food processing room or the second area into the first area. 23. The method of claim 19, wherein maintaining at least that food processing room and the second area at least at the second level of cleanliness when transporting the food product from the first area into the second area and when transporting the food product from the second area into that food processing room comprises maintaining at least that food processing room at a fourth level of cleanliness that is greater than the second level of cleanliness. 24. The method of claim 23, wherein maintaining at least that food processing room at the fourth level of cleanliness comprises limiting access to that food processing room to personnel operating food processing devices located in that food processing room, to appropriate supervisory personnel and to personnel maintaining that food processing room and equipment contained within that food processing room. 25. The method of claim 24, wherein maintaining at least that food processing room at the fourth level of cleanliness comprises: having the second area at a first air pressure; maintaining that food processing room at an air pressure that is greater than the first air pressure; and transporting the food product from the second area into that food processing room through the passage comprises passing the food product through the passage from the second area into that food processing room while passing the ambient atmosphere through the passage from that food processing room into the second area. 26. The method of claim 19, wherein: the first area comprises at least: a first portion that includes a holding area where the food product is held before it is processed in that food processing room, and a packaged food receiving area that receives the closed packages from that food processing room, at least that food processing room having a second passage to the packaged food receiving area; and transporting the closed package out of that food processing room comprises transporting the closed package through the second passage to the packaged food receiving area; and maintaining at least the packaged food receiving area at the first level of cleanliness when receiving the closed packages from that food processing room comprises at least one of: (a) requiring persons passing between the first portion and the packaged food receiving area to undergo another cleaning procedure when passing between the first portion and the packaged food receiving area; or (b) having the packaged food receiving area at a first air pressure, maintaining that food processing room at an air pressure that is greater than the first air pressure, and transporting the closed packages from that food processing room through the second passage into that food processing room while passing the ambient atmosphere through the passage from that food processing room into the second area; or (c) inspecting closed packages for faults, sanitizing closed packages having faults, and returning the sanitized closed packages having faults back into that food processing room. 27. The method of claim 19, wherein maintaining at least the first area at the first level of cleanliness when holding the food product in the first area and when transporting the food product from the first area into the second area further comprises preventing raw food products from entering the first area. 28. The method of claim 19, wherein maintaining at least the first area at the first level of cleanliness when holding the food product in the first area and when transporting the food product from the first area into the second area further comprises: accepting only previously cooked and sealed food products into the first area; cleaning an outer surface of a packaging that seals the previously cooked and sealed food product; removing the packaging from around the previously cooked and sealed food product; and applying a lethality treatment to the unsealed food product before transporting the unsealed food product into the second area. 29. The method of claim 28, wherein maintaining at least the first area at the first level of cleanliness when holding the food product in the first area and when transporting the food product from the first area into the second area further comprises: cleaning the outer surface, removing the packaging and applying the lethality treatment in a treatment room of the first area that is maintained at a first air pressure; having other portions of the first area and portions of the second area adjacent to the treatment room each at an air pressure that is above the first air pressure such that an ambient atmosphere in those other portions of the first area and the second area flows into the treatment room; and exhausting an ambient air in the treatment room to outside of the food processing facility. 30. The method of claim 18, wherein transporting the food product from the first area into the second area comprises: transporting the food product from a holding area of the first area into a treatment area of the first area; applying a lethality treatment to the food product in the treatment area before transporting the food product into the second area, wherein transporting the food product from the first area into the second area comprises transporting the treated food product from the treatment area into the second area. 31. The method of claim 30, wherein: the food product comprises a processed meat product; and applying the lethality treatment to the processed meat product in the treatment area comprises at least one of: passing the processed meat product through a hot liquid bath, and passing the processed meat product through a radiant heat treatment. 32. The method of claim 31, wherein passing the processed meat product through a hot liquid bath comprises passing the processed meat product through an oil bath. 33. The method of claim 31, wherein passing the processed meat product through a radiant heat treatment comprises passing the processed meat product through at least one infra-red heating treatment. 34. The method of claim 18, further comprising: having at least the second area at a first air pressure; maintaining that food processing room at an air pressure that is greater than the first air pressure; wherein transporting the food product from the second area into that food processing room comprises passing the food product through the passage from the second area into that food processing room while passing the ambient atmosphere through the passage from that food processing room into the second area. 35. The method of claim 18, wherein transporting the food product from the first area into the second area comprises: transporting the food product from a holding area of the first area into a treatment area of the second area; applying a lethality treatment to the food product in the treatment area before transporting the food product into that food processing room, wherein transporting the food product from the second area into that food processing room comprises transporting the treated food product from the treatment area into that food processing room. 36. The method of claim 35, wherein: the food product comprises a processed meat product; and applying the lethality treatment to the processed meat product in the treatment area comprises passing the processed meat product through a radiant heat treatment. 37. The method of claim 36, wherein passing the processed meat product through a radiant heat treatment comprises passing the processed meat product through at least one infra-red heating treatment. 38. The method of claim 1, wherein: at least that food processing room has at least a first passage to a first area; and transporting the closed package out of that food processing room comprises transporting the closed package from that food processing room into the first area through the first passage. 39. The method of claim 38, further comprising further packaging the closed packages of the processed food product for shipping to a downstream user of the food product. 40. The method of claim 39, further comprising transporting the closed packages to the downstream user. 41. The method of claim 38, further comprising: having the first area at a first air pressure; and maintaining that food processing room at an air pressure that is greater than the first air pressure; wherein transporting the closed packages from that food processing room into the first area comprises passing the closed packages through the first passage from that food processing room into the first area while passing the ambient atmosphere through the first passage from that food processing room into the first area. 42. The method of claim 41, wherein at least that food processing room has a second passage to the first area, the method further comprising: inspecting each closed package as it is transported out of that food processing room to identify any closed packages requiring repackaging; and transporting each closed package requiring repackaging back into that food processing room through the second passage while passing the ambient atmosphere through the second passage from that food processing room into the first area. 43. The method of claim 42, wherein transporting each closed package requiring repackaging back into that food processing room through the second passage comprises sanitizing each closed package requiring repackaging before, after or as that closed package requiring repackaging is transported back into that food processing room. 44. The method of claim 38, further comprising maintaining the first area at a first level of cleanliness when transporting the closed packages from that food processing room into the first area. 45. The method of claim 44, wherein maintaining the first area at the first level of cleanliness when transporting the treated food product from that food processing room into the first area comprises at least one of: requiring persons entering the first area to wear a clean first-type set of clothing; and requiring persons entering the first area to have undergone at least a first cleaning procedure prior to entering the first area. 46. The method of claim 45, further comprising maintaining that food processing room at a second level of cleanliness that is greater than the first level of cleanliness when transporting the closed packages from that food processing room into the first area. 47. The method of claim 46, wherein maintaining the first area at the first level of cleanliness and that food processing room at the second level of cleanliness when receiving the closed packages from that food processing room comprises at least one of: (a) having the packaged food receiving area at a first air pressure, maintaining that food processing room at an air pressure that is greater than the first air pressure, and transporting the closed packages from that food processing room through the second passage into that food processing room while passing the ambient atmosphere through the passage from that food processing room into the second area; or (b) having the packaged food receiving area at a first air pressure, maintaining that food processing room at an air pressure that is greater than the first air pressure, and inspecting each closed package as it is transported out of that food processing room to identify any closed packages requiring repackaging, and transporting each closed package requiring repackaging back into that food processing room through the second passage while passing the ambient atmosphere through the second passage from that food processing room into the first area. 48. The method of claim 47, wherein transporting each closed package requiring repackaging back into that food processing room through the second passage comprises sanitizing each closed package requiring repackaging before, after or as that closed package requiring repackaging is transported back into that food processing room. 49. A method for reducing contamination by an undesirable micro-organism within a food processing facility that processes a food product, wherein the food processing facility comprises: a plurality of food processing rooms, each food processing room comprising at least one food processing device and at least one food packaging device, each food processing room to be at a first level of cleanliness; at least one distribution area, each distribution area adjacent to at least some of the food processing rooms, each distribution area to be at a second level of cleanliness that can be below the first level of cleanliness; at least one receiving area, each receiving area adjacent to at least some of the food processing rooms, each receiving area to be at a third level of cleanliness that can be below the first and second levels of cleanliness; at least one buffer area adjacent to at least one of at least one receiving area or at least one distribution area, the buffer area to be at least at the third level of cleanliness that can be below the first and second level of cleanliness; at least one common area adjacent to the at least one buffer area, each common area to be at a fourth level of cleanliness that can be below the third level of cleanliness; a plurality of sanitizing stations, at least one sanitizing station located between a common area and a buffer area and at least one sanitizing station located between a buffer area and an adjacent receiving or distribution area; the method comprising: requiring persons entering the at least one buffer area to have undergone a first sanitizing procedure prior to or upon entering that buffer area; requiring persons remaining in the at least one buffer area or exiting a buffer area into the receiving area to wear a first-type set of clothing; and requiring persons exiting the buffer area into the at least one distribution area or a food processing room to wear a second-type set of clothing; limiting access to the distribution area, the receiving area and the food processing rooms to persons having at least a first predetermined level of food safety training; limiting access to a food processing room to personnel operating food processing devices located in that food processing room, to supervisory personnel and to personnel maintaining that food processing room and equipment contained within that food processing room; and requiring persons entering the at least one distribution area, the at least one receiving area or a food processing room to have undergone a second cleaning procedure prior to or upon exiting the buffer area. 50. A food processing facility, comprising: a plurality of food processing rooms, each food processing room comprising at least one food processing device and at least one food packaging device, each food processing room at a first level of cleanliness; at least one distribution area, each distribution area adjacent to at least some of the food processing rooms, each distribution area at a second level of cleanliness that can be below the first level of cleanliness; at least one receiving area, each receiving area adjacent to at least some of the food processing rooms, each receiving area at a third level of cleanliness that can be below the first level of cleanliness; at least one buffer area adjacent to at least one of at least one receiving area or at least one distribution area, each buffer area at a fourth level of cleanliness that can be below the second level of cleanliness; at least one common area adjacent to at least one buffer area, each common area at a fifth level of cleanliness that can be below the fourth level of cleanliness; a plurality of sanitizing stations, at least one sanitizing station located between a common area and an adjacent buffer area and at least one sanitizing station located between a buffer area and an adjacent receiving or distribution area. 51. The food processing facility of claim 50, further comprising a drain system comprising a plurality of drain lines and at least one catch basin, each drain line connected between one of the at least one catch basin and one of the plurality of food processing rooms. 52. The food processing facility of claim 51, wherein, each drain line is connected directly between the catch basin and the food processing room that it connects and each drain line connected to a particular catch basin connects to that catch basin at least at one of a) a unique position about the perimeter of the catch basin or b) a unique axial position along an axis of the catch basin. 53. The food processing facility of claim 51, wherein each drain line has a closing device that is usable to close that drain line such that that drain line can be filled with fluid from the closing device back to the food processing room to which that drain line is connected. 54. The food processing facility of claim 51, wherein the drain system further comprises a second drain line that is connected at one end to one of the at least one distribution area at least at one connection point and to one of the at least one catch basin at another end. 55. The food processing facility of claim 54, wherein the second drain line connects to that catch basin at least at one of a) a unique position about the perimeter of the catch basin or b) a unique axial position along an axis of the catch basin relative to any drain lines connected between that catch basin and one of the plurality of food processing rooms. 56. The food processing facility of claim 54, wherein that second drain line has a closing device that is usable to close that drain line such that the second drain line can be filled with fluid from the closing device back to that distribution area. 57. The food processing facility of claim 51, wherein the drain system further comprises a second drain line that is connected at one end, at least at one connection point, to at least one of a) at least one of the at least one buffer area or b) at least one of the at least one receiving area and to one of the at least one catch basin at another end. 58. The food processing facility of claim 57, wherein the second drain line connects to that catch basin at least at one of a) a unique position about the perimeter of the catch basin or b) a unique axial position along an axis of the catch basin relative to any drain lines connected between that catch basin and one of the plurality of food processing rooms. 59. The food processing facility of claim 50, further comprising a curb system comprising a plurality of curbs that reduce an ability of food pathogens to migrate along or under walls of the food processing facility between the plurality of food processing rooms, between a food processing room and the at least one distribution area, the at least one receiving area and the at least one buffer area, between the at least one distribution area and the at least one buffer area, between the at least one receiving area and the at least one buffer area and between the at least one buffer area and the at least one common area, the plurality of curbs comprising: a first type of curb, the first type of curb used in at least the plurality of food processing rooms and providing a first level of protection against the migration of food pathogens; a second type of curb, the second type of curb used in at least one of a) at least one of the at least one distribution area or b) at least one of the at least one buffer area, and providing a second level of protection against the migration of food pathogens that is less than the first level; and a third type of curb, the third type of curb used in at least one of a) at least one of the at least one buffer area or b) at least one of the at least one receiving area, and providing a third level of protection against the migration of food pathogens that is less than the second level. 60. The food processing facility of claim 59, wherein the first type of curb comprises: a mass of concrete adjacent to a wall and a floor of the food processing facility; an antimicrobial-type stainless steel skirt around the mass of concrete, the stainless steel skirt extending between the wall and the floor and extending into the floor; and a flexible sealant provided at a joint between the stainless steel skirt and the floor. 61. The food processing facility of claim 59, wherein the second type of curb comprises: a mass of concrete adjacent to a wall and a floor of the food processing facility; a non-anti-microbial stainless steel skirt around the mass of concrete, the stainless steel skirt extending between the wall and the floor and extending into the floor; and a flexible sealant provided at a joint between the stainless steel skirt and the floor. 62. The food processing facility of claim 59, wherein the third type of curb comprises a mass of concrete adjacent to a wall and a floor of the food processing facility. 63. The food processing facility of claim 50, further comprising an air handling system, comprising: a plenum connected to at least some of the plurality of food processing rooms: a first bacterial-grade filter connected between the plenum and the ambient atmosphere outside the facility; for each connected food processing room, a second bacterial-grade filter connected between the plenum and that food processing room; and a plurality of separate ventilation and cooling subsystems, each ventilation and cooling subsystem connected to a different one of the at least some food processing rooms, each ventilation and cooling subsystem drawing air from that connected food processing room, chilling the withdrawn air and returning the chilled air to that connected food processing room. 64. The food processing facility of claim 63, wherein the ventilation and cooling subsystem comprises: a housing; a ventilation and cooling unit located in the housing; a supply inlet from the associated food processing room into the housing; a return outlet from the housing into the associated food processing room; and an exhaust duct from the associated food processing room to the outside of the food processing facility, a controllable damper provided in the exhaust duct and useable to controllably open and close the exhaust duct. 65. The food processing facility of claim 64, wherein the ventilation and cooling unit provides air to the associated food processing room at a rate sufficient to raise an air pressure in the associated food processing room above an air pressure in an adjacent distribution area. 66. The food processing facility of claim 50, wherein at least one buffer area includes a treatment room where a lethality treatment is applied to the food product before it is processed in the food processing rooms, the treatment room connected to other portions of that buffer area and to at least one distribution area, the food processing facility further comprising an exhaust subsystem that connects the treatment room to an outside of the food processing facility, wherein the exhaust system maintains an air pressure in the treatment room at a level that is below an air pressure in the other portions of the buffer area and an air pressure in the at least one connected distribution area. 67. A food processing facility usable to process a food product in an environment having low risk for contamination, comprising: a plurality of food processing rooms, each food processing room comprising at least one food processing device and at least one food packaging device; a first area, at least some of the plurality of food processing rooms having a first passage to the first area; a second area that includes at least some of a holding area, a treatment room, a buffer area and a packaged food receiving area, at least some of the plurality of food processing rooms having at least a second passage to the packaged food receiving area; and a third area that includes at least some of a break room, restrooms, a locker room, at least one office and a reception area; wherein: the first area and the plurality of food processing rooms are each maintained at least at a first level of cleanliness; the second area is maintained at a second level of cleanliness that is less than the first level of cleanliness; and the third area has a third level of cleanliness that can be less than the second level of cleanliness. 68. The food processing facility of claim 67, further comprising a first transport system that conveys portions of the food product to be processed from the holding area to the treatment area. 69. The food processing facility of claim 68, further comprising at least one lethality treatment device in the treatment area, each lethality treatment device usable to apply a lethality treatment to the portions of the food product conveyed to the treatment area. 70. The food processing facility of claim 69, further comprising a second transport system that conveys the treated food product into the first area. 71. The food processing facility of claim 70, further comprising, in the first area, at least one of a chilling device that reduces a surface temperature of the treated food product to a desired temperature or at least one second lethality treatment device, the treated food product transported through at least one of the chilling device or at least one second lethality treatment device. 72. The food processing facility of claim 71, further comprising, at least partially in the first area, a third transport system that conveys the treated food product from the at least one of the chilling device or at least one second lethality treatment device into at least one food processing room through the first passage. 73. The food processing facility of claim 69, wherein the at least one lethality treatment device is at least one of: at least one hot liquid bath; at least one chemical sanitizer; and at least one heat treating device that applies a radiant heat treatment. 74. The food processing facility of claim 73, wherein the at least one hot liquid bath comprises at least one oil bath. 75. The food processing facility of claim 73, wherein the at least one heat treating device comprises at least one infra-red treatment device that applies an infra-red heating treatment. 76. The food processing facility of claim 67, further comprising, in the first area, at least one of a chilling device that reduces a surface temperature of the food product to a desired temperature or at least one lethality treatment device, the food product transported through at least one of the chilling device or at least one lethality treatment device. 77. The food processing facility of claim 76, further comprising a transport system that conveys the food product from the at least one of the chilling device or at least one lethality treatment device into at least one food processing room through the first passage. 78. The food processing facility of claim 67, further comprising a ventilation and cooling system that ventilates and cools at least the plurality of food processing rooms. 79. The food processing facility of claim 78, wherein the ventilation and cooling system comprises: a plenum connected to at least some of the plurality of food processing rooms: a first bacterial-grade filter connected between the plenum and the ambient atmosphere outside the facility; for each connected food processing room, a second bacterial-grade filter connected between the plenum and that food processing room; and a plurality of separate ventilation and cooling subsystems, each ventilation and cooling subsystem located in a dedicated housing and connected to a different one of the at least some food processing rooms, each ventilation and cooling subsystem drawing air from that connected food processing room, chilling the withdrawn air and returning the chilled air to that connected food processing room. 80. The food processing facility of claim 79, wherein: for each different one of the at least some food processing rooms, the separate ventilation and cooling subsystem of that connected food processing room supplies the chilled air to that food processing room such that that food processing room has an internal temperature near the freezing point of water and is at an air pressure that is greater than a first air pressure within the first area; and the chilled air in that food processing room passes through the first passage from that food processing room into the first area. 81. The food processing facility of claim 80, further comprising an air handling subsystem usable to exhaust air from the treatment room to the ambient atmosphere outside of the food processing facility. 82. The food processing facility of claim 81, wherein the air handling subsystem maintains the treatment room at a second air pressure that is less than the first air pressure within the first area. 83. The food processing facility of claim 79, wherein: for each different one of the at least some food processing rooms, the separate ventilation and cooling subsystem of that connected food processing room supplies the chilled air to that food processing room such that that food processing room has an internal temperature near the freezing point of water and is at an air pressure that is greater than a first air pressure within the packaged food receiving area; and the chilled air in that food processing room passes through the second passage into the packaged food receiving area. 84. The food processing facility of claim 79, wherein each food processing room further includes a duct from that food processing room to the ambient atmosphere outside of the food processing facility, the duct having a device usable to controllably close the duct, the duct usable to exhaust air from that food processing room to the ambient air outside of the food processing facility. 85. The food processing facility of claim 67, further comprising a drain system comprising: at least one collection basin, and, for each food processing room: a drain in that food processing room; a drain line connected solely between that drain and one of the at least one collection basin, an outlet of that drain line into that collection basin being offset from any other drain outlets ending at that collection basin; and a closure structure that allows the drain line to be closed so that that drain line can be filled with a desired liquid. 86. The food processing facility of claim 67, further comprising a plurality of sanitizing stations, at least one sanitizing station located between the first area and the second area, at least one sanitizing station located between the second area and the third area, and at least one sanitizing station located between the packaged food receiving area and other portions of the second area. 87. The food processing facility of claim 67, further comprising a drain system comprising a plurality of drain lines and at least one catch basin, each drain line connected between one of the at least one catch basin and one of the plurality of food processing rooms. 88. The food processing facility of claim 87, wherein, each drain line is connected directly between the catch basin and the food processing room that it connects and each drain line connected to a particular catch basin connects to that catch basin at least at one of a) a unique position about the perimeter of the catch basin or b) a unique axial position along an axis of the catch basin. 89. The food processing facility of claim 87, wherein each drain line has a closing device that is usable to close that drain line such that that drain line can be filled with fluid from the closing device back to the food processing room to which that drain line is connected. 90. The food processing facility of claim 87, wherein the drain system further comprises a second drain line that is connected at one end to one of the at least one distribution area at least at one connection point and to one of the at least one catch basin at another end. 91. The food processing facility of claim 90, wherein the second drain line connects to that catch basin at least at one of a) a unique position about the perimeter of the catch basin or b) a unique axial position along an axis of the catch basin relative to any drain lines connected between that catch basin and one of the plurality of food processing rooms. 92. The food processing facility of claim 90, wherein that second drain line has a closing device that is usable to close that drain line such that the second drain line can be filled with fluid from the closing device back to that distribution area. 93. The food processing facility of claim 87, wherein the drain system further comprises a second drain line that is connected at one end, at least at one connection point, to at least one of a) at least one of the at least one buffer area or b) at least one of the at least one receiving area and to one of the at least one catch basin at another end. 94. The food processing facility of claim 93, wherein the second drain line connects to that catch basin at least at one of a) a unique position about the perimeter of the catch basin or b) a unique axial position along an axis of the catch basin relative to any drain lines connected between that catch basin and one of the plurality of food processing rooms. 95. The food processing facility of claim 67, further comprising a curb system comprising a plurality of curbs that reduce an ability of food pathogens to migrate along or under walls of the food processing facility between the plurality of food processing rooms, between a food processing room and the at least one distribution area, the at least one receiving area and the at least one buffer area, between the at least one distribution area and the at least one buffer area, between the at least one receiving area and the at least one buffer area and between the at least one buffer area and the at least one common area, the plurality of curbs comprising: a first type of curb, the first type of curb used in at least the plurality of food processing rooms and providing a first level of protection against the migration of food pathogens; a second type of curb, the second type of curb used in at least one of a) at least one of the at least one distribution area or b) at least one of the at least one buffer area, and providing a second level of protection against the migration of food pathogens that is less than the first level; and a third type of curb, the third type of curb used in at least one of a) at least one of the at least one buffer area or b) at least one of the at least one receiving area, and providing a third level of protection against the migration of food pathogens that is less than the second level. 96. The food processing facility of claim 95, wherein the first type of curb comprises: a mass of concrete adjacent to a wall and a floor of the food processing facility; an antimicrobial-type stainless steel skirt around the mass of concrete, the stainless steel skirt extending between the wall and the floor and extending into the floor; and a flexible sealant provided at a joint between the stainless steel skirt and the floor. 97. The food processing facility of claim 95, wherein the second type of curb comprises: a mass of concrete adjacent to a wall and a floor of the food processing facility; a non-anti-microbial stainless steel skirt around the mass of concrete, the stainless steel skirt extending between the wall and the floor and extending into the floor; and a flexible sealant provided at a joint between the stainless steel skirt and the floor. 98. The food processing facility of claim 95, wherein the third type of curb comprises a mass of concrete adjacent to a wall and a floor of the food processing facility. 99. A method for returning a food processing room of a food processing facility to a first level of cleanliness after that food processing room has become contaminated with a food pathogen, wherein the food processing facility has a plurality of food processing rooms, each food processing room comprising at least one food processing device and at least one food packaging device, the method comprising: raising a temperature within that food processing room to a desired temperature while maintaining at least one other food processing room in operation; maintaining the temperature within that food processing room at the desired temperature for a period of time sufficient to kill the food pathogen; and returning the temperature within that food processing room from the desired temperature to an operational temperature. 100. The method of claim 99, further comprising raising a temperture within at least one other food processing room that is close to that food processing room to a temperature that tends to avoid damage to the food processing facility that could occur when that food processing room is raised to the desired temperature. | BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is directed to systems, methods and structures for reducing the likelihood of contamination of processed foods by bacteria, other microorganisms, or other pathogens. 2. Related Art As food quality, sanitation and refrigeration practices have become better, the presence in processed foods of most common bacteria that affect food safety has been substantially reduced. While this has improved food safety overall, it presents the opportunity for more marginalized, less common bacteria and other food pathogens, which are otherwise unable to compete with such more common bacteria, to proliferate and colonize food product(s) as they are processed. For example, Listeria monocytogenes (hereafter “LM” or “Listeria”), which is inhibited by competition from more common bacteria, and thus naturally prevented from reaching fatal concentrations, is sometimes able to colonize food product(s) as they are being processed. Because Listeria, unlike more common bacteria and other food pathogens, is able to grow well in refrigerated conditions, and because most, if not all, competing bacteria have been eliminated from the food product(s) being processed, there is little or no competition to the Listeria bacteria to keep it from growing to fatal concentrations when Listeria contaminates food. At the same time, the U.S. government has instituted numerous programs and testing regimes to ensure that food products are pathogen-free, i.e., are not adulterated. For example, the presence of a food pathogen on a ready-to-eat meat product renders the meat product adulterated under the provisions of the Meat Inspection Act and/or the Poultry Inspection Act. If adulterated, the ready-to-eat meat product cannot be shipped. Additionally, if the ready-to-eat meat product has already been shipped, it must be recalled. Moreover, in most, if not all, conventional food processing facilities, even if the source of adulteration of a particular lot of food product can be traced to a single processing element, such as a food slicer, in that food processing facility, it is difficult, if not impossible, to determine which particular food items may have come in contact with that source of adulteration. As a result, the typical recall involves all products passing through a food processing facility during the time of potential adulteration to ensure that no adulterated food product remains available for sale to the ultimate consumer. The U.S. Department of Agriculture (USDA) has determined, for example, that Listeria is a hazard reasonably likely to occur in a slicing operation. Slicing operations are relatively high risk because pathogenic Listeria monocytogenes is ubiquitous and grows at refrigerated temperatures. Thus, because Listeria is ubiquitous, it is very difficult to prevent Listeria from colonizing processed food product(s) at points between an upstream lethality treatment and a downstream packaging operation, such as at a slicing operation. Furthermore, because sliced meats are “ready-to-eat”, they are typically removed from packaging and consumed without any consumer-applied lethality treatment, such as cooking. SUMMARY OF THE DISCLOSURE Bacteria and other food pathogens that are not well controlled by the current regimes of lethality treatment followed by refrigeration, such as Listeria, provide significant challenges in preparing and packaging processed food product(s) so they do not become adulterated. For example, common industry practice is to have multiple food processing devices, such as slicers, and multiple downstream packaging machines in the single food processing room of the food processing facility. However, this provides a chance for contamination by bacteria or other food pathogens spreading from machine to machine by migration across wet floors, through the air for microrganisms, such as Listeria, that are able to aerosol and float around on water droplets in the air, by food processing and supervisory personnel moving from one machine to another in the single processing room, by food processing personnel moving freely from one food processing room to another, and/or by maintenance personnel working on multiple similar and dissimilar machines within a single food processing area or freely moving between separate food processing areas. This invention provides food processing facilities, systems and methods that reduce the ability of bacteria and other food pathogens to spread from outside of the facilities into and through the facilities to contaminate food processing machinery and food being processed within the facility. This invention separately provides food processing facilities, systems and methods which place one or more food processing machines and one or more associated packaging machines forming a single set of food processing devices in a separate food processing room. This invention separately provides food processing facilities, systems and methods that reduce the ability of food pathogens to migrate from a contaminated location or machine and/or from outside of the facility to an uncontaminated location or machine by controlling the movement of persons between unsecure, semi-secure and secure portions of the food processing facility. This invention separately provides food processing facilities, systems and methods that reduce the ability of food pathogens to migrate from a contaminated location or machine and/or from outside of the facility to an uncontaminated location or machine by limiting food processing personnel to working in a single food processing rooms containing a single set of food processing devices. This invention separately provides food processing facilities, systems and methods that reduce the ability of contamination to migrate from an adulterated location or machine and/or from outside of the facility to an unadulterated location or machine by limiting the movement of food processing personnel between food processing rooms containing a single set of food processing devices. This invention separately provides food processing facilities, systems and methods that reduce the ability of contamination to migrate from an adulterated location or machine and/or from outside of the facility to an unadulterated location or machine by controlling the movement of maintenance personnel between food processing rooms. This invention separately provides food processing facilities, systems and methods that reduce the ability of contamination to migrate from an adulterated location or machine and/or from outside of the facility to an unadulterated location or machine by separately providing at least commonly-used maintenance materials in each separate food processing room. This invention separately provides food processing facilities, systems and methods that reduce the ability of contamination to migrate from an adulterated location or machine and/or from outside of the facility to an unadulterated location or machine by placing each set of one or more food processing devices and one or more associated packaging devices in a separate high-pressure area such that air flows from the high-pressure areas into areas adjacent to the high pressure areas. This invention separately provides food processing facilities, systems and methods that reduce the ability of contamination to migrate from an adulterated location or machine and/or from outside of the facility to an unadulterated location or machine by providing separate food processing rooms, each having separate, dedicated ventilating and/or air conditioning (VAC) systems. This invention separately provides food processing facilities, systems and methods that reduce the ability of contamination to migrate from an adulterated location or machine and/or from outside of the facility to an unadulterated location or machine by drawing all initial and make-up air supplied to a particular VAC system from outside the food processing facility containing the individual food processing rooms. This invention separately provides food processing facilities, systems and methods that use a first conveyor system to convey unpackaged lethality-treated food product(s) into a food processing room to be further processed in that room and a separate packaged food output conveyor system that conveys food product packaged in that food processing room to a downstream handling system. This invention separately provides food processing facilities, systems and methods that provide higher air pressure regions in the food processing rooms and lower air pressure regions around input and output conveyor systems such that air flows from the food processing room into the conveyor areas. This invention separately provides food processing facilities, systems and methods where each food processing room has a sloped floor leading to a dedicated floor drain and line that continues uninterruptedly from the food processing room to a point where the drain line can be plugged independently of any of the other drain lines. This invention separately provides food processing facilities, systems and methods for plugging the drain and filling the drain line and the lower portions of the associated food processing room with a disinfectant or the like which sanitizes the plugged portion of the drain, the room floor and the lower portions of the structures in the food processing room. This invention separately provides food processing facilities, systems and methods in which air is circulated into the food processing rooms at a sufficiently high velocity to dry and maintain dry the floor and any equipment services within a particular food processing room between sanitizing cleaning procedures. This invention separately provides food processing facilities, systems and methods where the joints between walls, walls and ceiling, and/or walls and floor are specially designed and treated to inhibit movement of water or moisture between individual floor, ceiling or wall panels, and into or between separate food processing rooms. This invention separately provides food processing facilities, systems and methods that use special floor-wall joint structures to inhibit moisture transfer between food processing rooms and between food processing rooms and food delivery areas, food boxing areas, and other food processing areas and from occurring beneath the walls dividing each separate food processing room from other food processing rooms and from common areas. This invention separately provides food processing facilities, systems and methods that include footwear sanitizing stations within the food processing facility at interfaces between different food processing and/or common areas. This invention separately provides food processing facilities, systems and methods for receiving food product(s) to be processed in the food processing facility and for sanitizing the exterior surfaces of the food product(s) to be processed at the food processing facility before delivering the food product(s) to be processed to the separate food processing rooms. In various exemplary embodiments of food processing facilities, methods and systems according to this invention, any persons entering secure and semi-secure areas of the food processing facility must wear specialized footwear, which must be sanitized upon entering and exiting semi-secure and secure areas of the food processing facility. Persons moving between various ones of the semi-secure and secure areas of the food processing facility must also pass through footwear sanitizers as they move between the different sub-portions of the food processing facility. Employees entering a secure area, where the food product is exposed, must wear a clean “secure area” uniform. All other persons entering the semi-secure areas of the food processing facility must wear designated clothing and are prevented from entering the secure areas of the food processing facility. In various exemplary embodiments, upon a person exiting the secure areas to a semi-secure or unsecure area, the current secure area uniform worn by that person must be discarded and a new sanitized secure area uniform must be worn and footwear appropriately sanitized before re-entering any secure area. Any equipment, such as tools, that are to be taken into one of the food processing rooms is desirably flushed with alcohol or otherwise sterilized before that equipment can be taken into that food processing room. In various exemplary embodiments of food processing facilities, systems and methods according to this invention, food product(s) to be processed entering even the semi-secure areas of the food processing facility must be pre-cooked and/or must have been otherwise subjected to appropriate protective and lethality treatments to ensure that the food product(s) are essentially free of adulterating pathogens when they enter the food processing facility. In various exemplary embodiments, the food product(s) must be received in casings, other sealing material or the like, which are also essentially free of adulterating pathogens. After being received at the food processing facility, and before any processing of the received food product(s), the casing, sealing material or the like are sanitized and the food product(s) are next removed from the casing, sealing material or the like and one or more further lethality treatments are applied to kill any pathogens that might somehow have reached the surface of the food product(s). After the one or more lethality treatments, the received food product(s) are transported, for example, by conveyor through a food produce delivery area, to each of the separate food processing rooms for further food processing. In general, the food product(s) delivery areas through which the food product(s) pass between the final lethality treatments and the food processing rooms are also treated as secure or sterile regions such that any source of contamination is excluded from such regions. In various exemplary embodiments, the food product(s) pass from the delivery area, which is at a first pressure, through a delivery opening into a particular food processing room, which is maintained at a higher air pressure, such that air moves unidirectionally through the delivery opening in the direction opposite that of the food product(s) as they enter that food processing room. In various exemplary embodiments of food processing facilities, systems and methods according to this invention, once in a given food processing room, the food product(s) is processed and immediately packaged for transport out of the food processing facility while in that food processing room. The packaged food product(s) is then transported, for example, by conveyor, out of the higher air pressure food processing room into a second common area. Because the food processing room is also at a higher pressure than this second common area, air constantly moves unidirectionally through the exit opening in the direction of movement of the packaged food product(s). The packaged food product(s) from the various food processing rooms are then inspected for package integrity, further packaged, held under refrigerated conditions and prepared for transport to a customer for sale to the ultimate consumer. Any inspected package which lacks integrity is rerouted for another lethality treatment before repackaging in the food processing room from which it came. In various exemplary embodiments of food processing facilities, systems and methods according to this invention, should one of the isolated food processing rooms become contaminated, that room can be shut down and sterilized without affecting the operation of other food processing rooms. Furthermore, because all of the food product processed in that food processing room were separately packaged and identified while in that food processing room, the food product from that food processing room is inherently distinguishable from the food products processed in the other food processing rooms, and thus can be separately recalled or otherwise destroyed. If contaminated, that food processing room can then be sterilized using a combination of one or both of heat and chemical sanitizers. In addition, the drain for that room can be separately plugged and flushed for sanitizing reasons without affecting the operation of the drain lines of the other food processing rooms. In various exemplary embodiments of food processing facilities, systems and methods according to this invention, when repair or maintenance of the machinery in a given food processing room is required, maintenance personnel entering that food processing room must also be wearing secure area uniforms and go through the same sanitary procedures as the operators working in that food processing room. In various exemplary embodiments, if the maintenance personnel are coming from another food processing room, those maintenance personnel desirably don new, sanitary food processing uniforms. In various exemplary embodiments of food processing facilities, systems and methods according to this invention, each of the food processing rooms contains all of the supplies and tools necessary to perform common maintenance procedures and to repair the food processing equipment due to common or expected faults. Accordingly, for simple or common repairs or maintenance, the maintenance personnel do not need to carry any tools or supplies into that food processing room. If more unusual repairs or maintenance needs to be made, any parts, supplies or tools that must be carried into that food processing room by the maintenance personnel are desirably first subjected to an alcohol wash or other appropriate cleaning and/or sterilizing procedure before those parts, supplies and/or tools are carried by the maintenance personnel into that food processing room. These and other individual features and advantages which may be separately incorporated in various exemplary embodiments of systems and methods according to this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the systems, methods and facilities for processing food according to this invention. BRIEF DESCRIPTION OF DRAWINGS Various exemplary embodiments of the systems, methods and food processing facilities of this invention will be described in detail, with reference to the following figures, wherein: FIG. 1 is a schematic top plan view of a first exemplary embodiment of a food processing facility and food processing systems according to this invention; FIG. 2 is a schematic top plan view illustrating one exemplary embodiment of a drain system usable with the first exemplary embodiment of the food processing facility and related systems according to this invention shown in FIG. 1; FIG. 3 is a schematic top plan view of a second exemplary embodiment of a food processing facility and related systems according to this invention; FIG. 4 is a cross-sectional view of second and third exemplary embodiments of curb structures according to this invention; FIGS. 5 and 6 are schematic top and side views, respectively, of a first exemplary embodiment of a ventilating and air conditioning system for a food processing room according to this invention; FIGS. 7 and 8 are a flowchart outlining one exemplary embodiment of a method for processing a food product according to this invention; FIGS. 9 and 10 are a flowchart outlining one exemplary embodiment of a method for controlling movement of personnel within a food processing facility according to this invention; and FIG. 11 is a flowchart outlining one exemplary embodiment of a method for providing heating, ventilation and air conditioning to a given food processing room according to this invention. DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS As developed countries, such as the United States, consume ever larger percentages of processed food products, the safety of such processed food products has become of paramount importance. As a result, various governmental agencies in such developed countries have promulgated various rules and regulations which have improved food quality and safety and have substantially eliminated contamination or adulteration of such processed food products by most common food-born pathogens. However, this has opened up the possibility of contamination or adulteration by more marginalized food pathogens. That is, the most common food pathogens are those that grow most readily and rapidly on food products at room temperatures in standard environments, and can be controlled or lethally treated by refrigeration and heat treatment. However, in the absence of such pathogens controlled or eliminated by conventional refrigeration and heat treatment, other pathogens have shown the ability to grow and prosper under refrigerated conditions. For example, Listeria monocytogenes (“LM” or “Listeria”) is one such bacteria that is better able to tolerate colder temperatures than more common bacterial species. As a result, Listeria is able to successfully colonize and multiply at refrigeration temperatures that control the growth of more common bacteria. In fact, Listeria colonies can grow to concentrations in refrigerated processed food products that can cause fatal side affects in humans when such processed food products are consumed. As a result, current food safety standards generally require that contamination or adulteration of processed food products by Listeria be, ideally, completely avoided. The following detailed description of various exemplary embodiments of food processing facilities, systems and methods according to this invention are described relative to controlling the risk of Listeria monocytogenes adulteration of processed meat products. However, it should be appreciated that the food processing facilities, systems and methods illustrated by the exemplary embodiments described herein are equally applicable to other types of processed food products, such as dairy products, fruit and vegetable products, and the like. Moreover, it is likely that other bacteria and other pathogenic microorganisms, in addition to Listeria, such as Salmonella, are or will become of concern in the future. It should be appreciated that the food processing facilities, systems and methods according to this invention illustrated by the following exemplary embodiments are equally useful in reducing the ability of other pathogenic microorganisms to adulterate processed food products, such as meat products, dairy products, fruit and/or vegetable products, or the like. However, for ease of understanding and simplicity of discussion, the following detailed descriptions will disclose food processing facilities, systems and methods for reducing contamination or adulteration of processed meat products with particular reference to Listeria. FIG. 1 is a schematic top plan view of a first exemplary embodiment of a food processing facility 100 according to this invention that employs “single-line” food processing rooms and clean room-like procedures to both reduce the ability of Listeria monocytogenes or other pathogens to initially contaminate a single-line food processing room or other area of the food processing facility 100 from outside of the food processing facility 100, and, if a single-line food processing room or other area of the food processing facility 100 should become contaminated, reduce the likelihood that the contamination will spread to other single-line food processing rooms or other areas of the food processing facility 100. In particular, the food processing facility 100 shown in FIG. 1 is a meat and cheese slicing facility. However, it should be appreciated that various ones of the different structures of the food processing facility 100 described herein can be applied to food processing plants designed for processing other types of food products and other types of food processing operations. As shown in FIG. 1, previously-processed meat products are received at a receiving area 118 of the food processing facility 100 and stored in a food product storage cooler 110 until such time as a particular portion of the received food product is ready for further processing in the food processing facility 100. It should be appreciated that, in various exemplary embodiments, to reduce the likelihood that the food product to be processed in the food processing facility is not contaminated when it is received at the food processing facility 100, only previously processed food products, such as previously cooked meat products, are received and processed by the food processing facility 100. In various exemplary embodiments, to reduce this risk as much as possible, any raw or untreated food products are denied entry into the food processing facility 100. In various exemplary embodiments, the received processed meat product is a relatively long tubular cooked meat product which will be subsequently sliced at the food processing facility 100. Such long tubular cooked meat products are commonly referred to as “logs”. In various exemplary embodiments, these logs 114 have been encased in a sealed plastic casing after cooking and prior to arrival at the facility 100. In various exemplary embodiments according to this invention, the received food products, such as the encased logs, as received, are stored in specialized stainless steel containers, racks, or any other appropriate device that can be used to transfer the received food product to the food processing facility. The containers 116 allow different lots of the processed meat product or other received food product to be kept separately from other lots to avoid cross-contamination while the received food products are being transported and/or while the received food products are awaiting further processing. In various exemplary embodiments, the received ready-to-eat food products to be processed in the food processing facility 100 are transported to the food processing facility 100 on a “just-in-time” schedule. However, even in this case, it is often necessary to temporarily store the containers 116 in the storage cooler 110. By using the containers 116, only limited amounts of the processed food product need to be exposed when removing the logs 114 from the containers 116 for transport into the secure areas of the food processing facility 100. It should be understood that, in various exemplary embodiments, conventional enclosures (not shown) are used between the trailer of the delivery truck and the doorway to the receiving area 118 of the food processing facility 100 to minimize the possibility of contamination of the food product while moving the containers 116 from the trailer to the receiving area 118 of the food processing facility 100. The receiving area 118 where the containers 116 of received food product enter the food processing facility 100 and the storage cooler 110 are two portions of a semi-secure region 104, which also includes a buffer zone 115, that lies between generally unsecured areas where little or no effort is made to ensure that food pathogens are not present, and secure areas of the food processing facility 100, where extensive efforts are made to prevent food pathogens from entering such areas and to inhibit the spread of food pathogens should any be present in the secure areas. It should be appreciated that the terms “secure” and “semi-secure” refer to the efforts to exclude food pathogens and other microorganisms, and not to efforts directed to preventing theft, unauthorized access, terrorism or the like. In various exemplary embodiments, when a food log 114 (or any other processed food product) is to be removed from the storage cooler 110 for further processing, the container 116 containing that log 114 is typically removed from the storage cooler 110 and placed adjacent to a conveyor 112. The log 114 is removed from its container 116 and placed onto the conveyor 112, which conveys the log 114 into a treatment room 120. The treatment room 120 is used to reduce the presence of, and ideally completely remove, any bacteria or other pathogenic microorganisms, which may have opportunistically colonized the processed food products, before the processed food product is transported into the food processing facility 100. For example, for processed ready-to-eat meat logs 114, as previously indicated, the meat logs 114 are typically sealed in plastic casings when received from the upstream food processing facility that formed the processed meat logs 114. In various exemplary embodiments, the plastic-encased meat logs 114 are transported in the containers 116 from the storage cooler 110, removed from the containers 116 and placed onto the conveyor 112, which conveys the logs 114 through a sanitizing washer 111 to remove any pathogens which may be present on the exterior of the casing, and into the treatment room 120, where the cleansed plastic casing is removed from around the processed meat log 114 and discarded. The exterior surface of the processed meat log 114 is then subjected to a post-lethality treatment to reduce, and ideally eliminate, any bacteria or other pathogenic microorganisms that may have colonized the surface of the processed meat log 114. In various exemplary embodiments, the term “post-lethality treatment” means a treatment that is applied to the processed meat log 114 (or other food product to be processed in the food processing facility 100) after it was subjected to cooking or another upstream lethality treatment at the upstream food processing facility before being packaged for transport to the food processing facility 100. In various exemplary embodiments of the food processing facility 100, the post-lethality treatment applied in the treatment room 120 comprises running the meat log through a treatment device 122 and/or an infrared tunnel 125 (shown in the area 130) that heats the entire surface of the processed meat log 114 to a sufficiently high temperature that any pathogenic bacteria or other microorganisms which may be present on the surface of the meat log 114 are expected to be killed. The treatment device 122 can be a hot liquid bath, such as a hot oil bath or hot water bath, or a steam treatment device, or another appropriate device that obtains a product surface temperature that results in a 2 log reduction in the pathogen. In another exemplary embodiment, the meat log may be run through a conventional chemical sanitizer (not shown) employing, for example, a sanitizing solution comprising chlorine or peracedic acid. The treated meat log 114 (or other processed food product) is then transported on a conveyor 124 from the treatment device 122 and/or 125 that is within the treatment room 120 into a delivery area 130. In various exemplary embodiments, the conveyor 124 may deliver the treated meat log 114 to a cruster 128, such as a Vertical Rapid Cruster manufactured by Unitherm Food Systems of Bristow, Okla., which creates a uniform frozen crust in the surface of the meat log 114 to improve the sliceability of the meat log 114. From the cruster 128, the conveyor 124 delivers the crusted meat log 114 to a distribution conveyor 132 located in the delivery area 130. The distribution conveyor 132 is used to convey a particular meat log 114 or other treated food product to a desired one of a plurality of single-line food processing rooms 140. It should be appreciated that, in various exemplary embodiments, the treatment room 120 is another portion of the semi-secure region 104. In such exemplary embodiments, while the food product is unsealed and exposed in the treatment room 120, because of the treatment applied in the treatment room 120, the treatment room 120 does not need to be part of the secure area 106. However, if desired, the treatment room 120 can be made part of the secure area 106. It should also be appreciated that, in various exemplary embodiments, the treatment room 120 is equipped with an exhaust system 121 for maintaining a slightly negative atmospheric pressure in the treatment room 120. Thus, air will be pulled out of the delivery area 130 into the treatment room 120, and then, together with any fumes from the fryer 122, is exhausted out of the facility 100 to the outdoors by the exhaust system. Alternatively, one or more infrared tunnels 125 may be located in the delivery area 130, as shown in FIG. 1. Accordingly, in various other exemplary embodiments, while a lethality treatment is applied to a particular log 114 or other processed food product, that log 114 or other processed food product does not go through the treatment room 120. In this case, a dedicated lethality treatment or device may be provided for one or more sets of one or more such food processing rooms 140 that process such a log or other processed food product. For example, if the treatment applied in the treatment room 120 is applied using a heated oil bath, but the customer does not want the processed food product to go through such a process, or the food product cannot withstand such a treatment, that food product will skip the treatment room 120. In this case, the food product can be removed from its container 116 and the outside of the casing sanitized. The sanitized food product is then delivered to the delivery area 130, the casing removed, and the uncased food product 114 transported to the appropriate food processing room 140. At some point between having the casing removed and being transported into the appropriate food processing room 140, the lethality treatment, such as passing through an infrared tunnel 125 shown in FIG. 1, or the like, is applied to the uncased food product 114 while in the delivery area. The various single-line food processing rooms 140 are the only locations within the food processing facility 100 where the food product to be processed, such as the meat logs 114, is actually processed, other than receiving lethality treatments, such as those described above. It should be appreciated that only a single line of food processing devices may be provided in each of the various “single-line” food processing rooms 140. This remains the case even if the single line of food processing devices in a given food processing room 140 is divided into two separate food processing paths or sets, as there is a single food product inlet from the food delivery 130 to a single-line food processing room 140 and a single outlet from a single-line food processing room 140 to a packaged food receiving area 150. The food processing devices in that single-line food processing room 140 are independent of the food processing devices in any other single-line food processing room. In any case, the product packaged in any such single-line food processing room 140 will receive an unique identity code, printed on the package, which will enable the operators to trace every package produced in the food processing facility 100 back to the individual food processing room 140 in which it was processed and packaged. In various exemplary embodiments, each set or line of devices in a single-line food processing room 140 includes two or more serially-connected food processing elements. For example, in various exemplary embodiments of the food processing facility 100, each of the single-line food processing rooms 140 is a slicing room where the meat logs 114 are converted into sliced meat product. In some exemplary embodiments of such slicing rooms, the output of an upstream food processing device is directed to a single downstream food processing device and only one such line is present in any given single-line food processing room 140. For slicing operations, a single-line food processing room 140 will typically include a slicing machine 142 and a packaging machine 146. It should also be appreciated that, in various exemplary embodiments according to this invention, any food product leaving a single-line food processing room 140 will be packaged before it leaves that single-line food processing room 140. It should be appreciated that “packaged” generally encompasses providing a sealed barrier between the processed food product and its ambient environment, such that any pathogens in the ambient environments that the processed food product experiences after leaving the single-line food processing room 140 and until the opening of the package, either by the end consumer or within another downstream food processing facility, are unable to penetrate the barrier and contaminate or adulterate the processed food product. As shown in FIG. 1, a transfer conveyor 134 receives the meat logs 114 or other processed food product from the distribution conveyor 132 and conveys the meat logs 114 or other processed food product from the delivery area 130, through a passage or opening in a wall separating that single-line food processing room 140 from the delivery area 130, and into the interior of the single-line food processing room 140. It should be appreciated that the processed food product can go directly from the treatment room 120 to one of the single-line food processing rooms 140. In various other exemplary embodiments, the treated food product is chilled, for example, by using the cruster 128 described above, before being delivered to the single-line food processing room 140. Using the cruster 128 both reduces the surface temperature of the log 114, and arrests any bacterial activity that could otherwise occur on the surface of that log 114 after passing through the oil bath or infrared tunnel, and also beneficially makes the log 114 easier to slice. The chilled log 114 or other food product is then transported to the appropriate food processing room 140 as described above. It should be appreciated that, in various exemplary embodiments, the passage or opening for the conveyor 134 through the wall separating the single-line food processing room 140 from the delivery area 130 is desirably sized on the order of the meat log 114 or other processed food product being conveyed by the transfer conveyor 134. It should also be appreciated that the single-line food processing room 140 is desirably kept at a higher internal pressure and a colder temperature than the pressure and temperature within the delivery area 130. As a result, there is a positive or increasing pressure gradient along the direction of travel of the transfer conveyor 134 such that there is an unidirectional air flow out of the single-line food processing room 140 into the delivery area 130. This ensures that any pathogens which may be present in the atmosphere in the delivery area 130, however unlikely, cannot travel by aerosol action or air flow from the delivery area 130 into a particular single-line food processing room 140. Once in a given single-line food processing room 140, each meat log 114 or other processed food product received from the delivery area 130 passes generally (i.e., more or less) serially through the various food processing and/or packaging machines that form the single food processing line contained within that single-line food processing room 140. As shown in FIG. 1, the meat log 114 or other processed food product transported by the transfer conveyor 134 travels to a feeder station 142, where the meat log 114 or other processed food product is fed to a slicing machine 143 and sliced into a plurality of separate slices of a desired thickness. A number of slices are gathered into a portion and the plurality of slices of the sliced food product forming a portion are then conveyed together by a second transfer conveyor 144 to, and packaged by, a packaging machine 146. In various exemplary embodiments, the sliced meat or other processed food product is packaged into thermoformed plastic cavities, which are then flushed with a gas as a plastic sheet is heat sealed to the cavity rim to form a hermetic or other impervious seal. In contrast, in various other exemplary embodiments, the sliced meat or other processed food product portion is vacuum packaged and sealed while in the single-line food processing room 140. It should be appreciated that, in various other exemplary embodiments, different types of food processing equipment will be contained within the single-line food processing room 140. In some exemplary embodiments, regardless of the types and numbers of food processing devices contained within the single-line food processing room 140, the various food processing devices will be organized such that a single line or series of food processing devices, through which all of the received meat logs 114 or other processed food products pass, is formed. That is, in such exemplary embodiments, the various food processing devices contained within the single-line food processing room 140 are not organized into two separate, effectively parallel lines or the like. By having only a single line of series-connected food processing devices in each single-line food processing room 140, each single-line food processing room 140 becomes essentially a separate food processing facility. Thus, if any one of the food processing devices in a single one of the single-line food processing rooms 140 becomes contaminated, only the processed food product which passed through that single-line food processing room 140 could be contaminated. Should a particular lot of processed food product which passed through that single-line food processing room 140 need to be recalled and/or destroyed before shipping, that processed food product lot can be dealt with in the knowledge that none of the other processed food products produced by the other single-line food processing rooms 140 in the food processing facility 100 need to be recalled the contamination present only within that first single-line food processing room 140. Likewise, should a particular device within the single-line food processing room 140 become contaminated, there will be a concern that all of the processed food product passing through that single-line food processing room 140 during the contamination period may have come into contact with that particular contaminated food processing device and thus, may need to be recalled and/or destroyed or otherwise rehabilitated. However, it should be appreciated that, in less rigorous exemplary embodiments, a particular “single-line” food processing room 140 could contain more than one of a particular type of food processing equipment that is fed by a set of one or more input conveyor(s) and discharged to a set of one or more output conveyor(s). However, in this case, while the risk of cross-contamination between food processing lines in different food processing rooms 140 has been reduced, the ability of Listeria or other pathogenic microorganisms to cross contaminate parallel machines within a single-line food processing room 140 is not inhibited. The packaged food product is then output from the packaging device 146 on to a third transfer conveyor 148. The third transfer conveyor 148 transports the packaged food product into the receiving area 150. In particular, the third transfer conveyor 148 passes through a passage or opening in a wall that separates the single-line food processing room 140 containing that transfer conveyor 148 from the receiving area 150. In various exemplary embodiments, the passage or opening is desirably sized on the order of the size of the packaged food product being transferred out of that single-line food processing room 140. In various exemplary embodiments, as the packaged food product enters the receiving area 150 on the third conveyor 148, the packaged food product is inspected. If the inspection reveals that a particular packaged food product needs to be re-packaged, that packaged food product is placed on a return conveyor (not shown) that conveys that packaged food product back into the food processing room 140 that it came from. The returned packaged food product's package is sanitized before or as it enters that single-line food processing room 140. Once in that food processing room 140, the returned food product package is opened and disposed of and the returned food product is placed into a new package and resealed. In contrast, in some exemplary embodiments, the third transfer conveyor 148 deposits the packaged processed food product from that single-line food processing room 140 onto a collection conveyor 152 that collects various processed and packaged food products from the various single-line food processing rooms 140. Once on the collection conveyor 152, the packaged processed food product can be inspected, boxed, collected and/or palletized for shipping to a finished product cooler, a warehouse, or the ultimate consumer. It should also be appreciated that, like the delivery area 130, the receiving area 150 is at a lower atmospheric pressure and temperature than the single-line food processing rooms 140, although the receiving area 150 does not need to be at either the same pressure or the same temperature as the delivery area 130. As a result, there is a decreasing, or negative, pressure gradient along the direction of travel of the third transfer conveyor 148 as it passes through the opening in the wall separating the single-line food processing room 140 from the receiving area 150. As a result, there is a unidirectional air flow from the single-line food processing rooms 140 into the receiving area 150, effectively preventing the migration of any pathogens present in the receiving area 150 into the single-line food processing rooms 140 through the limited openings in the walls separating the single-line food processing rooms 140 from the receiving area 150. Likewise, there will be a similar unidirectional air flow from the single-line food processing rooms 140 to the receiving area 150 surrounding the return conveyors (not shown) and the packages being returned to the single-line food processing rooms 140 for repackaging. To further reduce the ability of Listeria and other pathogenic microorganisms from migrating from place to place within the food processing facility 100, the food processing facility 100 is divided into the first region 102, the second region 104 and the third region 106. In general, the first region 102, which corresponds to the unsecured area, includes such facilities as locker rooms where the personnel employed in the food processing facility 100 can change their clothes, lunch and/or break rooms where the personnel can take their breaks and/or eat breakfast, lunch or dinner, restrooms, offices for the management personnel for the food processing facility 100 and the like. The first region 102 can also include conference and meeting rooms, visitor reception areas and the like. Because these areas are in the first region 102, rather than in the second region 104, it is likely that the personnel employed by the food processing facility 100 will make multiple trips between the first region 102 and the second or third regions 104 or 106 during the typical work shift. The second region 104, which corresponds to the semi-secure area, includes a clean uniform storage 117 in the buffer zone 115, the storage cooler 110, the receiving area 118, the treatment room 120, and the receiving area 150. The third region 106, which corresponds to the secure areas, includes the delivery area 130 and the various single-line food processing rooms 140. In general, movement within the first region 102 and access to the first region 102 from outside the food processing facility 100 by authorized personnel is generally not restricted. Accordingly, employees and other authorized personnel can freely enter the first region 102 from the second region 104 and from outside the food processing facility 100. Thus, the first region 102 can be referred to as an “unsecure area”. In contrast, access to the various rooms and areas forming the second region 104 and movement between those regions and the first region 102 is strictly controlled. In particular, movement between the first region 102 and the second region 104 requires passing through a sanitizing station 160, such as the sanitizing station 161 located between the first area 102 and the buffer zone 115. In addition, in various exemplary embodiments, movement from the first region 102 into the second region 104 requires that special clothing or uniforms be donned prior to or immediately after passing through the sanitizing station 161. Similarly, moving from the second region 104 into the first region 102 requires passing through the sanitizing station 161 and removal of the special clothing or uniform. In various exemplary embodiments, the required clothing includes rubber boots or other appropriate footwear that is generally impervious to liquids and from which Listeria and other pathogenic microorganisms can be relatively easily removed. In such exemplary embodiments, the sanitizing station 161 includes footwear scrubbing and/or sanitizing devices that use both mechanical devices and chemical applications to remove and/or kill any bacteria that may be present on the rubber boots. When personnel pass between the first and second regions 102 and 104, they are required to pass through the sanitizing station 161 to ensure that no Listeria or other pathogenic microorganisms that may be present on the employees' footwear survives the sanitizing station, such that such microorganisms are not transported between the first and second regions 102 and 104. In various other embodiments, in addition to or instead of the rubber footwear, the specialized clothing can include head coverings, smocks and other over-clothing, and even can include specialized clean room-type sanitized suits or uniforms. Additionally, in various exemplary embodiments, personnel leaving the second region 104 and entering the first region 102, before or after passing through the sanitizing station 161, are required to remove the specialized clothing and recycle it for sanitizing. Because reasonably strict procedures, including that cooked-only food product be stored and processed in the second region 104, the type of food processing not permitted in the second region 104, and the movement of food processing personnel between the first region 102 and the second region 104, are designed to reduce the likelihood that Listeria or other pathogenic microorganisms are able to enter or migrate into the region 104, the region 104 can be referred to as a semi-secure area. Additionally, in various exemplary embodiments, in addition to controlling how the food processing personnel move between the first region 102 and the second region 104, the types of personnel that are permitted to move between the first region 102 and the second region 104 can also be controlled. In various exemplary embodiments, access to the second region 104 can be limited to food processing personnel and visitors having designated certifications, such as having completed food safety specialist training and certification. Once in the second region 104, access to the delivery area 130, the receiving area 150, and the single-line food processing rooms 140 can be further controlled by requiring food processing personnel to pass through further sanitizing stations 160 between the second region 104 and the delivery area 130, the receiving area 150 and the single-line food processing rooms 140. Thus, in such exemplary embodiments, the food processing personnel pass through additional sanitizing stations 160 to enter the delivery area 130, the single-line food processing rooms 140, or the receiving room 150 from the buffer zone 115, and when passing back into the buffer zone 115 from the single-line food processing rooms 140, the distribution area 130, or the receiving area 150. In various exemplary embodiments, while access to the buffer zone 115 may be permitted, access to the third region 106, i.e., at least the delivery area 130 and the single-line food processing rooms 140, can be limited to food processing personnel having completed food safety specialist training and certification and having specific duties within such areas. Furthermore, in various exemplary embodiments, access to the single-line food processing rooms 140 is further limited only to operators of the machines forming the single-line food processing system in the single-line food processing room 140, to supervisors and quality control/assurance personnel, and to maintenance personnel who require entry into a particular single-line food processing room 140 in order to maintain and/or repair the equipment in that single-line food processing room 140. In various exemplary embodiments, any food processing personnel entering such a single-line food processing room 140 must wear a clean room-style protective suit or other appropriate full-body covering, in addition to the prescribed footwear. Similarly, in various exemplary embodiments, any food processing personnel entering the delivery area 130 are also required to wear such a clean room-style protective suit or other appropriate full-body covering. In various exemplary embodiments, if a food processing employee moves from the third region 106 back out into any portion of the second region 104, that person must remove the protective suit or other full body covering and don a new such protective suit or full-body covering before re-entering the third region 106. Thus, the likelihood is reduced that any Listeria or other pathogenic microorganisms that have been able to migrate into the second or third regions 104 or 106 will be able to migrate further into the third region 106, i.e., into the delivery area 130, or even further into the single-line food processing rooms 140. Likewise, the likelihood that any Listeria or other pathogenic microorganisms which may be present in a particular single-line food processing room 140 will migrate out of that single-line food processing room 140 into either the other areas of the second region 104 or another single-line food processing room 140 is reduced. Because of the additional controls on movement of personnel between the third region 106, i.e., the single-line food processing rooms 140 and the delivery area 130, and the other portions of the second region 104, the delivery area 130 and the single-line food processing rooms 140 can also be referred to as the “secure areas”. FIG. 2 illustrates a first exemplary embodiment of a drain system usable in the food processing facility 100 according to this invention. Conventional drains are a potential source of environmental contamination. This drain system forms another aspect of the food processing facility 100 that is usable to reduce the likelihood that Listeria or other pathogenic microorganisms will migrate from the other portions of the third region 106 or the second region 104 into the single-line food processing rooms 140, or vice versa, or between individual single-line food processing rooms 140. As shown in FIG. 2, each single-line food processing room 140 has its own dedicated drain line 180-187. As shown in FIG. 2, each drain line 180-187 extends directly from a particular single-line food processing room 140 to one of a number of collection manholes or catch basins 170, such as the manholes or catch basins 171, 172, and 173. In particular, as shown in FIG. 2, the various drain lines 180-187 do not intersect each other prior to reaching the particular catch basin 170 to which they are connected. Additionally, the outlet of each of the drain lines 180-187 connects to and preferably discharges by gravity into the corresponding catch basis 170 at a location that is spaced apart from the outlets of the other drains 180-187 both circumferentially, as can be seen in FIG. 2, and/or axially. That is, the outlet for each drain 180-187 into the corresponding catch basin 170 is spaced apart from the other outlets both along the circumference of the catch basin 170 and along the axis of the catch basin 170 that extends into and out of the drawing of FIG. 2. Accordingly, any waste materials flushed down a particular one of the drains 180-187 from a particular single-line food processing room 140 into the corresponding catch basin 170 generally will not splash into, be directed into, or otherwise contaminate any of the other ones of the drains 180-187 that are connected to that catch basin 170. While FIG. 2 shows only food processing room drains 180-187, it should be understood that the facility 100 will have as many such drains as there are such single-line food processing rooms 140. Furthermore, the common drain lines 190, such as the drain lines 191 and 192, which are designed to receive waste materials from, for example, the distribution room 130 and/or the receiving room 150, respectively, are also connected to the catch basins 170 at locations that are spaced apart from the drain lines 180-187 both circumferentially and/or axially, so that waste from the various single-line food processing rooms 140 does not contaminate the drain lines 190 or vice versa. In various exemplary embodiments, the drain lines 180-187 are designed with minimum bends or elbows, such that there are minimal locations in the drain lines 180-189 where waste material can collect within those drain lines 180-187. In various exemplary embodiments, each of the drain lines 180-187 can be fitted with an end cap, damper or valve 188 or other appropriate device that allows that drain line 180-187 to be sealed, such that it can be backfilled for its entire length from the corresponding single-line food processing room 140 with a cleaning and/or sanitizing agent or the like. In various exemplary embodiments, this would allow that drain line 180-187, if it were to become contaminated with Listeria or other pathogenic microorganisms, to be cleaned and/or sterilized to remove such contamination. In various exemplary embodiments, such caps, valves or other appropriate structures are located at the outlet ends of the drain lines 180-187 at the catch basins 170. In various exemplary embodiments, the catch basins 170 are connected to a waste disposal system, such as a sewer system, a waste water treatment system, or the like. In various exemplary embodiments, the catch basins 170 are located outside of the walls of the food processing facility 100. In various exemplary embodiments, the floors of the single-line food processing rooms 140 are sloped toward the drain fixtures 194 at the upper ends of the drain lines 180-187, such that any liquids, including cleaning and flushing liquids which may drop or be directed onto the sloped floors, are directed into the drain fixtures 194 and the drain lines 180-187, regardless of where in the single-line food processing room 140 the liquid may contact the floor. In various exemplary embodiments, the drain fixtures 194 may be constructed of anti-microbial stainless steel, such as are supplied by Unitherm Food Systems of Bristow, Okla. FIG. 3 illustrates a second exemplary embodiment of a food processing facility 200 according to this invention. It should be appreciated that the structures shown in FIG. 3 generally correspond to similar structures shown in FIG. 1 and/or FIG. 2, including door openings and doors between the various rooms and areas as shown in FIGS. 1 and 2, and otherwise as may be necessary or convenient. FIG. 3 additionally shows a number of exemplary curb structures used within the storage cooler 210, the treatment room 220, the delivery area 230, the various single-line food processing rooms 240, the receiving area 250 and the other regions which form the various portions of the second region 104. These curbs are located at the base of the walls of the various portions of the food processing facility 200 used to divide the space within the second region 104 into the various rooms discussed above. These curbs may include three different types of curbs, which have increasing abilities to slow down or prevent the migration of Listeria or other pathogenic microorganisms along or under the walls within the regions 104 and 106. As shown in FIG. 3, these curbs include a first type of curb 202, which is used to line the interior surfaces of walls of those spaces where the processed food product that is processed within the food processing facility 200 is not expected to be present. This first type of curb 202 can also be used to line those walls where the processed food product is present in only a packaged state. Such regions include hallway areas 262, maintenance areas 264, dry supply storage area 260, the receiving area 250, a shipping dock area 270 and the like. The second type of curb 204 is used to line those walls where it is likely that the processed food product to be processed in the food processing facility 200 will be present, either in a sealed casing or in an unpackaged state but is not being processed. Such regions include the storage cooler area 210, the buffer zone 215, the treatment room 220, the delivery area 230 and adjacent areas. A third type of curb 206 is used to line the interior walls of the single-line food processing rooms 240. In general, the first type of curb 202 provides relatively lesser protection against the migration of Listeria and other pathogenic microorganisms. The second type of curb 204 provides an intermediate level of protection against migration of Listeria and other pathogenic microorganisms. The third type of curb 206 provides relatively greater protection against the migration of Listeria and other pathogenic microorganisms. In general, the curbs 202-206 protect against migration of such pathogenic microorganisms along and under the walls separating the various spaces within the regions 104 and 106 of the food processing facility 200. In particular, the curbs 202-206 generally prevent water and other liquids from moving from the enclosed spaces within the regions 104 and 106 to spaces under the walls, either along the walls or to the other sides of the walls, because Listeria and other pathogenic microorganisms can be carried by movements of water and other liquids under the walls and into other spaces within the regions 104 and 106 of the food processing facility 200 unless measures are taken to prevent such intrusions and movements. FIG. 3 also shows one exemplary embodiment of a cooling and air circulation system for the storage cooler 210, the delivery area 230, the receiving area 250, the shipping dock area 270 and the finished product cooler 280, which includes a plurality of evaporator cooler fans 196 mounted in the upper portions of the identified areas. The evaporator coolers may be positioned parallel to one or more walls of an enclosed space, as shown in the storage cooler 210, the shipping dock area 270 and the finished product cooler 280, or perpendicular to a wall as shown in back-to-back relation in the elongated spaces of the delivery area 230 and the receiving area 250, or in any other position which will result in a vigorous circulation of cold air sufficient to provide constant air movement over surfaces of and/or within the identified areas and their contents to prevent the condensation or accumulation of moisture on any such surfaces. The maintenance of dry surfaces within the facility 200 by the circulation of cold air minimize the opportunities for Listeria or other pathogens to colonize on, and subsequentially spread from such surfaces within such areas to elsewhere within the facility 200. FIG. 4 shows one exemplary embodiment of a wall and floor structure 300 and various exemplary embodiments of curb structures 400 and 500 usable in food processing facilities 100 or 200 according to this invention. As shown in FIG. 4, the wall and floor structure 300 comprises a floor 310 against or into which a wall 340 is set. In general, the floor 310 is formed of concrete or other hard and generally impervious substance and may be coated with a lithium-based sealant or other appropriate protective coating. In various exemplary embodiments, the walls 340, as well as the ceilings, are constructed of 4″ thick freezer panels 344 with urethane foam insulation or the like having an insulating value of R43.5. Typically, all joints between wall and ceiling panels 340 are dovetailed to provide foam-to-foam interfaces and are caulked to prevent any movement of water between or along the panels. The walls 340 may include galvanized steel skins 342 placed on both sides of the foam panels 344. In various exemplary embodiments, water-impervious polymer coatings are formed over the steel skins 342. It should be appreciated that, in various exemplary embodiments, the curbs 202 are formed of concrete as shown in FIG. 4 coated similarly to the floor 310. In contrast, in various exemplary embodiments, the curbs 204 and 206 are keyed stainless steel curbs such as that shown in FIG. 4. In various exemplary embodiments, the curbs 206 use anti-microbial stainless steel curbs manufactured by Unitherm Food Systems. The curbs 204 are standard stainless steel. As shown in FIG. 4, a simple concrete curb 400 includes a concrete mass 420 that contains reinforcing iron bars 410. The iron rebar 410 also attaches the concrete curb 400 to the floor 310. Caulking or other sealants are provided at the joints between the concrete curb 400 and the floor 310, and the concrete 400 and the galvanized steel skin 342 on a wall 340. As further shown in FIG. 4, a second type of curb 500 includes a groove 510 cut into the floor 310, as well as reinforcing iron bars 520 that extend into the floor 310. A concrete mass 530 extends around the reinforcing iron rebar 520. A stainless steel cover 540 extends around the concrete mass 530 and into the groove 510. The top of the stainless steel curb 540 is connected to the stainless steel skin of the wall 340. An epoxy or polyurethane or the like seal 550 is placed in and/or around the groove 510 to seal the stainless steel curb 540 into the groove 510 to form an impervious barrier to liquids that may be present on the wall 340 and/or the floor 310. It should be appreciated that the curb structure 500 is particularly useful as the curbs 204 and 206 described above. Other curb designs which provide a liquid impervious barrier between the floor and the walls under expected conditions, and which also provide physical protection to the bases of the walls to reduce physical damage to the walls from impacts from lift trucks, pallets, equipment or the like, and/or which further inhibit the presence or growth of microorganisms are also acceptable for the curbs 202, 204 and 206. FIGS. 5 and 6 are top and side plan views of the ventilating and air conditioning (VAC) system for each of the plurality of single-line food processing rooms 140 and 240 described above. That is, in various exemplary embodiments, each of the single-line food processing rooms 140 and 240 has its own separate VAC system, for which FIGS. 5 and 6 illustrate one exemplary embodiment. Each separate VAC system 600 is mounted on the outer surface of the ceiling 209 for the corresponding single-line food processing room 140 to which that VAC system 600 is connected. As shown in FIGS. 5 and 6, each separate VAC system 600 includes an air inlet 610 in which a high efficiency particulate filter 612, such as a high-efficiency particulate air (HEPA) filter, is fitted. The VAC system 600 also includes a “doghouse” 620 in which a ventilation and air conditioning unit 624 is mounted. The air inlet 610 connects the corresponding single-line food processing room 140 or 240 to a space 650 above the single-line food processing rooms 140 or 240, while an air inlet 622 connects that single-line food processing room 140 or 240 to the interior of the doghouse 620. Accordingly, the ventilation and air conditioning unit 624 draws air from the single-line food processing room 140 or 240 through the inlet 622, possibly conditions the withdrawn air, and returns the withdrawn air to that single-line food processing room 140 or 240 through a duct 630 and a return inlet 632. It should be appreciated that all initial and make-up air that is supplied to the separate VAC systems 600 and has been drawn from outside the food processing facility 100 or 200 first passes through an outside air intake 670, as shown in FIG. 1, and into the space 650 above the single-line food processing rooms 140 or 240. In various exemplary embodiments, the outside air intake 670 also includes a HEPA filter 672 or the like. Because each inlet 610 also includes an intake HEPA filter 612, all air drawn from outside the food processing facility 100 or 200 passes through two HEPA filters or the like before entering into the individual single-line food processing rooms 140 or 240. The VAC system 600 for this particular single-line food processing room 140 or 240 circulates the air into that single-line food processing room 140 or 240 through the duct or air plenum 630 at near freezing-level temperatures and relatively high speeds to create a positive air pressure within that single-line food processing room 140 or 240. That is, a pressure greater than ambient atmospheric pressure is created in each single-line food processing room 140 or 240 by the VAC system 600. Accordingly, no ambient air will be able to flow from the rest of the food processing facility 100 or 200 into any of the single-line food processing rooms 140 or 240. Rather, during food processing operations, room air will flow out of each of the single-line food processing rooms 140 or 240 through the openings through which the incoming and outgoing transport conveyors pass between the delivery area 130 or 230 and the receiving area 150 or 250. If any air needs to be exhausted from the single-line food processing room 140 or 240, such as after a cleaning operation, an air outlet 642 in the ceiling 209 allows air to pass from the single-line food processing room 140 or 240 into an exhaust duct 640, controlled by a damper and control 644, which guides exhaust air through a roof 660 of the facility 100 or 200 and thus entirely out of the food processing facility 100 or 200, while directing that exhaust air away from the air inlet 670. In various exemplary embodiments, all exhaust air from any portion of the facilities is exhausted entirely out of the facilities to the outdoors. It should be appreciated that, in various exemplary embodiments, the air is introduced into the particular single-line food processing rooms 140 or 240 by the VAC system 600 at a substantial velocity of, for example, 22 miles per hour, to quickly dry and maintain dry the floor and any equipment surfaces to avoid wet surfaces where Listeria or other pathogenic microorganisms could grow or prosper. In various exemplary examples, this air is exhausted through the exhaust duct 640 to the outside during and after the introduction of water or other liquids into the corresponding single-line food processing room 140 or 240, such as by daily cleaning, backfilling of a room drain and floor area with a disinfectant, or the like. It should also be appreciated that, in various exemplary embodiments, any piping of any kind entering the single-line food processing rooms 140 or 240, or any other areas of the plant, is preferentially orienting vertically down from the utility space above and through the ceiling 209, such that horizontal pipe runs extending within the single-line food processing rooms 140 or 240 and other plant areas are eliminated or minimized, as horizontal pipe can provide surfaces where moisture can condense and collect. It should also be appreciated that, in various exemplary embodiments, a selected single-line food processing room 140 or 240 and all of the contents of that single-line food processing room 140 or 240, may be heated to a temperature and for a time that should be sufficient to be lethal to any Listeria bacteria or other pathogenic microorganisms that might be found on, or suspected to be present on, the devices forming the single-line food processing system, including the food processing devices, the packaging equipment or any other locations within that single-line food processing room 140 or 240. Thus, in such exemplary embodiments, it would not be necessary to completely remove the equipment or physically reach every pathogen on the equipment in that single-line food processing room 140 or 240 in order to sanitize the equipment in that single-line food processing room 140 or 240. 100981 It should be appreciated that, in such exemplary embodiments, the walls 208 and the ceiling 209 used to separate each of the single-line food processing rooms 140 or 240 from each other and from the areas within the region 104 of the food processing plant 200 should be designed to be able to withstand experiencing such elevated temperatures for sufficiently long periods of time to allow the food processing equipment in that single-line food processing room 140 or 240 to be heat sterilized. It should also be appreciated that it may be desirable, depending on the construction of the walls 208 and/or the ceiling 209, to warm up one or more adjacent ones of the normally refrigerated single-line food processing rooms surrounding the single-line food processing room 140 or 240 to be sterilized, or to heat one or more adjacent single-line food processing rooms 140 or 240 having a common-pour floor section with the single-line food processing room 140 or 240 to be sterilized, to avoid creating too large a temperature differential between the single-line food processing room 140 or 240 being sterilized and the surrounding single-line food processing rooms 140 or 240. It should also be appreciated that the temperature of the room or rooms to be heated could be raised and lowered slowly between normal operating temperature and heat sterilization temperature to avoid structural damage. FIGS. 7 and 8 are a flowchart outlining one exemplary embodiment of a method for handling processed food product(s) within a food processing facility according to this invention. As shown in FIGS. 7 and 8, the method begins in step S100 and continues to step S105, where an initially-processed food product is received and possibly stored in a designated area of the food processing facility. As outlined above, in various exemplary embodiments, this designated area can be a short-term storage cooler or the like. Next, in step S110, a portion of the received food product is selected for processing by the food processing facility. In various exemplary embodiments, as outlined above, the selected portion can be a meat log or the like. Next, in step S115, the selected portion of the food product is transferred from the designed area to a treatment area or the like. Operation then continues to step S120. In step S120, at least one post-processing lethality treatment is applied to the selected portion of the food product. As outlined above, this is done to reduce the likelihood that an opportunistic adulterant, such as Listeria or other adulterating microorganism, has colonized the surface of the selected portion of the food product to be processed. Next, in step S125, the selected portion of the food product is transferred from the treatment area or the like to a near-sterile food product delivery area. In general, the selected portion is transferred using any desirable appropriate devices which reduce the likelihood that the surface of the food product will be recolonized with Listeria or other pathogenic microorganisms as it is transferred from the treatment area or the like through the food product delivery area to the particular single-line food processing room 140 in which that food product will be further processed. It should be appreciated that steps S120 and S125 can be reversed, in that the food product can be treated after it is in the delivery area rather than before it enters the delivery area. Then, in step S130, the treated selected portion of the food product is transferred from the food product delivery area to a single-one food processing room through an opening in the wall separating the food product delivery area from the single-line food processing room. It should be appreciated that, in various exemplary embodiments, a positive pressure gradient, as outlined above, is applied to this opening to create a pressure differential across that opening. By forming a positive pressure gradient from the interior of the single-line food processing room to the food product delivery area, air moves through the opening toward the food product delivery area from the single-line food processing room. This tends to prevent air-borne microorganisms, such as Listeria, from entering the single-line food processing room. Operation then continues to step S135. In step S135, the received portion of the food product is processed in the single-line food processing room using a set of one or more food processing devices. Then, in step S140, the processed food product is transferred within the single-line food processing room from the one or more food processing devices to one or more food packaging devices. Next, in step S145, the processed food product is packaged within the single-line food processing room. Operation then continues to step S150. In step S150, the packaged food product is transferred from the single-line food processing room to a receiving area through an opening in the wall separating the single-line food processing room from the receiving area. In various exemplary embodiments, a pressure gradient is created across that opening from the single-line food processing room to the receiving area to generate a unidirectional flow of air from the single-line food processing from into the receiving area. Next, in step S155, the packages of packaged food product are inspected for leakage or other faults with the packaging such that Listeria or other pathogenic microorganisms could migrate into that packaging. Next, in step S160, any leaking or defective food product packages are returned to the single-line food processing room 140 from which they came for re-sterilization and repackaging in the single-line food processing room, are discarded or otherwise appropriately dealt with. Operation then continues to step S165. In step S165, a determination is made whether the food product was packaged on a Friday or other designated day. It should be appreciated that Friday is used to allow the food product packaged on that day to be extensively inspected, sampled and tested for the presence of pathogens, while being held a sufficient time to receive the testing results from the lab before the product is shipped. Thus, it should be appreciated that any particular day of the week or any particular shift could be used in place of Friday in step S165, so long as sufficient time is allowed to pass before step S170 is carried out relative to such packaged food products. In particular, if the food was packaged on Friday or other designated time for such tests, operation continues to step S170. Otherwise, operation jumps to step S180. In step S170, the packaged food product(s) are stored until Monday, or for some other necessary or desired interval, while awaiting receipt of the test results showing that the food processing product is acceptable. Next, in step S175, if no contamination is found, the packaged food product(s) are prepared for shipping from the food processing facility. Otherwise, if contamination is found in any of the packaged food product(s) tested, appropriate steps may be taken to identify the single-line food processing room(s) within which the contaminated product was processed, to segregate all product from that room(s), and to take appropriate remedies or action to identify the source of the contamination and to properly dispose of or subject to additional lethality treatment the contaminated product and facilities. Operation then jumps to step S185. In contrast, in step S180, the uninspected packaged food product(s) are prepared for immediate shipping from the food processing facility. Then, in step S185, the packaged food product(s) are shipped from the food processing facility to either a downstream food processing facility, a downstream warehouse or other storage location, a retailer or the like. Operation then continues to step S190, where operation of the method ends. FIGS. 9 and 10 are a flowchart outlining one exemplary embodiment of a method for controlling movement of personnel within a food processing facility according to this invention. As shown in FIGS. 9 and 10, operation of the method begins in step S200, and continues to step S205, where a person wishing to enter the semi-secure or secure areas of the food processing facility dons appropriate footwear, such as, for example, rubber boots. Then, in step S210, the person proceeds through a sanitizing station to enter a buffer area. In the buffer area the person will be able to don an appropriate uniform. Next, in step S215, a determination is made which areas of the food processing facility the person wishes to enter. Operation then proceeds to step S220. In step S220, a determination is made whether the person wishes to enter the food delivery or food processing areas, i.e., the secure areas of the food processing facility. If so, operation continues to step S225. Otherwise, operation jumps to step S240. In step S225, a determination is made whether the person has completed appropriate food safety training. If not, operation continues to step S230. Otherwise, operation jumps to step S235. In step S230, because the person has not completed the appropriate food safety training to enter the food delivery or food processing areas, the person is denied access to these areas. Operation then returns to step S220. In contrast, in step S235, the person, having completed the appropriate food safety training, and thus being authorized to enter the food delivery or food processing areas, dons a full-body or other secure area uniform. Operation then jumps to step S245. In further contrast, in step S240, because the person does not wish to enter the food delivery or food processing areas, the person puts on a food transfer-type, or semi-secure area-type, uniform. Operation then proceeds to step S245. In step S245, the person proceeds from the buffer area to the authorized area(s) of the food processing facility the person, assuming the proper uniform is being worn, wishes to visit. Next, in step S250, a determination is made whether the person wishes to enter the packaged food receiving area, the food delivery area, or the food processing areas. If so, operation continues to step S255. Otherwise, operation jumps to step S260. In step S255, the person proceeds to a second boot sanitizing station to enter the desired area of the food processing facility. Operation then proceeds to step S260. In step S260, a determination is made whether the person wishes to exit the food processing facility completely or whether the person wishes to change to a different area of the food processing facility. If not, operation returns to step S260. Otherwise, if the person wishes to change which area of the food processing facility the person is in, operation continues to step S265. Else, if the person wishes to exit the secure and semi-secure areas, operation jumps to step S280. In step S265, a determination is made whether the person wishes to re-enter the food delivery or food processing areas from the buffer area or one of the other semi-secure areas of the food processing facility, such as the treatment room, the receiving area, the packaged food receiving area, the cold storage area or the like. If so, operation continues to step S270. Otherwise, operation jumps to step S275. In step S270, the person puts on a new full-body uniform and recycles the old full-body uniform for sanitation. Then, in step S275, the person proceeds to the appropriate boot sanitizing station. For example, if the person is leaving the food delivery or food processing areas into one of the semi-secure areas, the person will proceed through a footwear sanitizing station. Likewise, if the person is proceeding from the packaged food receiving area to another one of the semi-secure areas, the person will proceed through the appropriate footwear sanitizing station. Operation then returns to step S260. In contrast, in step S280, the person proceeds through the footwear sanitizing stations necessary to reach the unsecured areas of the food processing facility. Then, in step S285, the person recycles for sanitation whatever uniform the person is currently wearing. Next, in step S290, a determination is made whether the person wishes to re-enter the food processing area. This will occur when the person is returning from a visit to the restroom or from lunch or some other break. If so, operation returns to step S210. Otherwise, operation continues to step S295, where operation of the method stops. FIG. 11 is a flowchart outlining one exemplary embodiment of a method for cooling and ventilating a single-line food processing room according to this invention. As shown in FIG. 11 beginning in step S300, operation of the method continues to step S305, where air is drawn from outside of the food processing facility through an air inlet, through a bacterial grade filter, such as a HEPPA air filter or other appropriate filter device and into a plenum that supplies at least the food processing rooms. Then, in step S310, the filtered outside air is allowed to pass through a second filter into the associated single-line food processing room to provide twice filtered make-up air as needed. Next, in step S315, air is withdrawn from the associated single-line food processing room into a dedicated ventilating and air conditioning (VAC) enclosure. Operation then continues to step S320. In step S320, the temperature and humidity of the withdrawn air are reduced to near or below freezer-range temperature and humidity. Next, in step S325, the withdrawn and cooled air is returned to the single-line food processing room at high velocity to create higher than ambient air pressure in the single-line food processing room and maintain room temperature near freezing. Then, in step S330, due to the higher than ambient air pressure in the single-line food processing room, high pressure air is unidirectionally exhausted from the single-line food processing room through the openings in the walls that lead to the delivery and receiving areas. Operation then continues to step S335. In step S335, a determination is made whether the air in the single-line food processing room needs to be vented rather than recirculated. If not, operation returns to step S315. Otherwise, operation continues to step S340, where the high pressure air is exhausted from the single-line food processing room to outside of the food processing facility via one or more damper controlled ducts that direct the exhausted air away from the air inlet that is used to draw air from outside of the food processing facility into the bacterial grade filter. Operation then returns to step S310. It should be understood that the order of the steps of each of the foregoing methods is not limited to the order described and illustrated, but in exemplary embodiments can include any such step in any appropriate order which does not preclude or compromise other steps of the method. The above-outlined various exemplary embodiments of various structures, systems and techniques are each useful in reducing the ability of Listeria or other pathogenic microorganisms to enter food processing facilities, or migrate between, or cross contaminate, different food processing devices or food processing device lines. Thus, each of the various structures, systems and methods described herein are separately useful. When such structures, systems and methods are combined into various combinations, the ability of Listeria and other pathogenic microorganisms to invade or migrate between different food processing devices and/or lines is even further reduced. Thus, it should be appreciated that food processing facilities, systems and methods according to this invention do not need to use all or even a plurality of the various structures, systems and techniques disclosed herein. While this invention has been described in conjunction with the exemplary embodiments outlined above, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or that are or may be presently unforeseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the exemplary embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention. Therefore, the invention is intended to embrace all known or earlier developed alternatives, modifications, variations, improvements and/or substantial equivalents. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention This invention is directed to systems, methods and structures for reducing the likelihood of contamination of processed foods by bacteria, other microorganisms, or other pathogens. 2. Related Art As food quality, sanitation and refrigeration practices have become better, the presence in processed foods of most common bacteria that affect food safety has been substantially reduced. While this has improved food safety overall, it presents the opportunity for more marginalized, less common bacteria and other food pathogens, which are otherwise unable to compete with such more common bacteria, to proliferate and colonize food product(s) as they are processed. For example, Listeria monocytogenes (hereafter “LM” or “ Listeria ”), which is inhibited by competition from more common bacteria, and thus naturally prevented from reaching fatal concentrations, is sometimes able to colonize food product(s) as they are being processed. Because Listeria, unlike more common bacteria and other food pathogens, is able to grow well in refrigerated conditions, and because most, if not all, competing bacteria have been eliminated from the food product(s) being processed, there is little or no competition to the Listeria bacteria to keep it from growing to fatal concentrations when Listeria contaminates food. At the same time, the U.S. government has instituted numerous programs and testing regimes to ensure that food products are pathogen-free, i.e., are not adulterated. For example, the presence of a food pathogen on a ready-to-eat meat product renders the meat product adulterated under the provisions of the Meat Inspection Act and/or the Poultry Inspection Act. If adulterated, the ready-to-eat meat product cannot be shipped. Additionally, if the ready-to-eat meat product has already been shipped, it must be recalled. Moreover, in most, if not all, conventional food processing facilities, even if the source of adulteration of a particular lot of food product can be traced to a single processing element, such as a food slicer, in that food processing facility, it is difficult, if not impossible, to determine which particular food items may have come in contact with that source of adulteration. As a result, the typical recall involves all products passing through a food processing facility during the time of potential adulteration to ensure that no adulterated food product remains available for sale to the ultimate consumer. The U.S. Department of Agriculture (USDA) has determined, for example, that Listeria is a hazard reasonably likely to occur in a slicing operation. Slicing operations are relatively high risk because pathogenic Listeria monocytogenes is ubiquitous and grows at refrigerated temperatures. Thus, because Listeria is ubiquitous, it is very difficult to prevent Listeria from colonizing processed food product(s) at points between an upstream lethality treatment and a downstream packaging operation, such as at a slicing operation. Furthermore, because sliced meats are “ready-to-eat”, they are typically removed from packaging and consumed without any consumer-applied lethality treatment, such as cooking. | <SOH> SUMMARY OF THE DISCLOSURE <EOH>Bacteria and other food pathogens that are not well controlled by the current regimes of lethality treatment followed by refrigeration, such as Listeria, provide significant challenges in preparing and packaging processed food product(s) so they do not become adulterated. For example, common industry practice is to have multiple food processing devices, such as slicers, and multiple downstream packaging machines in the single food processing room of the food processing facility. However, this provides a chance for contamination by bacteria or other food pathogens spreading from machine to machine by migration across wet floors, through the air for microrganisms, such as Listeria, that are able to aerosol and float around on water droplets in the air, by food processing and supervisory personnel moving from one machine to another in the single processing room, by food processing personnel moving freely from one food processing room to another, and/or by maintenance personnel working on multiple similar and dissimilar machines within a single food processing area or freely moving between separate food processing areas. This invention provides food processing facilities, systems and methods that reduce the ability of bacteria and other food pathogens to spread from outside of the facilities into and through the facilities to contaminate food processing machinery and food being processed within the facility. This invention separately provides food processing facilities, systems and methods which place one or more food processing machines and one or more associated packaging machines forming a single set of food processing devices in a separate food processing room. This invention separately provides food processing facilities, systems and methods that reduce the ability of food pathogens to migrate from a contaminated location or machine and/or from outside of the facility to an uncontaminated location or machine by controlling the movement of persons between unsecure, semi-secure and secure portions of the food processing facility. This invention separately provides food processing facilities, systems and methods that reduce the ability of food pathogens to migrate from a contaminated location or machine and/or from outside of the facility to an uncontaminated location or machine by limiting food processing personnel to working in a single food processing rooms containing a single set of food processing devices. This invention separately provides food processing facilities, systems and methods that reduce the ability of contamination to migrate from an adulterated location or machine and/or from outside of the facility to an unadulterated location or machine by limiting the movement of food processing personnel between food processing rooms containing a single set of food processing devices. This invention separately provides food processing facilities, systems and methods that reduce the ability of contamination to migrate from an adulterated location or machine and/or from outside of the facility to an unadulterated location or machine by controlling the movement of maintenance personnel between food processing rooms. This invention separately provides food processing facilities, systems and methods that reduce the ability of contamination to migrate from an adulterated location or machine and/or from outside of the facility to an unadulterated location or machine by separately providing at least commonly-used maintenance materials in each separate food processing room. This invention separately provides food processing facilities, systems and methods that reduce the ability of contamination to migrate from an adulterated location or machine and/or from outside of the facility to an unadulterated location or machine by placing each set of one or more food processing devices and one or more associated packaging devices in a separate high-pressure area such that air flows from the high-pressure areas into areas adjacent to the high pressure areas. This invention separately provides food processing facilities, systems and methods that reduce the ability of contamination to migrate from an adulterated location or machine and/or from outside of the facility to an unadulterated location or machine by providing separate food processing rooms, each having separate, dedicated ventilating and/or air conditioning (VAC) systems. This invention separately provides food processing facilities, systems and methods that reduce the ability of contamination to migrate from an adulterated location or machine and/or from outside of the facility to an unadulterated location or machine by drawing all initial and make-up air supplied to a particular VAC system from outside the food processing facility containing the individual food processing rooms. This invention separately provides food processing facilities, systems and methods that use a first conveyor system to convey unpackaged lethality-treated food product(s) into a food processing room to be further processed in that room and a separate packaged food output conveyor system that conveys food product packaged in that food processing room to a downstream handling system. This invention separately provides food processing facilities, systems and methods that provide higher air pressure regions in the food processing rooms and lower air pressure regions around input and output conveyor systems such that air flows from the food processing room into the conveyor areas. This invention separately provides food processing facilities, systems and methods where each food processing room has a sloped floor leading to a dedicated floor drain and line that continues uninterruptedly from the food processing room to a point where the drain line can be plugged independently of any of the other drain lines. This invention separately provides food processing facilities, systems and methods for plugging the drain and filling the drain line and the lower portions of the associated food processing room with a disinfectant or the like which sanitizes the plugged portion of the drain, the room floor and the lower portions of the structures in the food processing room. This invention separately provides food processing facilities, systems and methods in which air is circulated into the food processing rooms at a sufficiently high velocity to dry and maintain dry the floor and any equipment services within a particular food processing room between sanitizing cleaning procedures. This invention separately provides food processing facilities, systems and methods where the joints between walls, walls and ceiling, and/or walls and floor are specially designed and treated to inhibit movement of water or moisture between individual floor, ceiling or wall panels, and into or between separate food processing rooms. This invention separately provides food processing facilities, systems and methods that use special floor-wall joint structures to inhibit moisture transfer between food processing rooms and between food processing rooms and food delivery areas, food boxing areas, and other food processing areas and from occurring beneath the walls dividing each separate food processing room from other food processing rooms and from common areas. This invention separately provides food processing facilities, systems and methods that include footwear sanitizing stations within the food processing facility at interfaces between different food processing and/or common areas. This invention separately provides food processing facilities, systems and methods for receiving food product(s) to be processed in the food processing facility and for sanitizing the exterior surfaces of the food product(s) to be processed at the food processing facility before delivering the food product(s) to be processed to the separate food processing rooms. In various exemplary embodiments of food processing facilities, methods and systems according to this invention, any persons entering secure and semi-secure areas of the food processing facility must wear specialized footwear, which must be sanitized upon entering and exiting semi-secure and secure areas of the food processing facility. Persons moving between various ones of the semi-secure and secure areas of the food processing facility must also pass through footwear sanitizers as they move between the different sub-portions of the food processing facility. Employees entering a secure area, where the food product is exposed, must wear a clean “secure area” uniform. All other persons entering the semi-secure areas of the food processing facility must wear designated clothing and are prevented from entering the secure areas of the food processing facility. In various exemplary embodiments, upon a person exiting the secure areas to a semi-secure or unsecure area, the current secure area uniform worn by that person must be discarded and a new sanitized secure area uniform must be worn and footwear appropriately sanitized before re-entering any secure area. Any equipment, such as tools, that are to be taken into one of the food processing rooms is desirably flushed with alcohol or otherwise sterilized before that equipment can be taken into that food processing room. In various exemplary embodiments of food processing facilities, systems and methods according to this invention, food product(s) to be processed entering even the semi-secure areas of the food processing facility must be pre-cooked and/or must have been otherwise subjected to appropriate protective and lethality treatments to ensure that the food product(s) are essentially free of adulterating pathogens when they enter the food processing facility. In various exemplary embodiments, the food product(s) must be received in casings, other sealing material or the like, which are also essentially free of adulterating pathogens. After being received at the food processing facility, and before any processing of the received food product(s), the casing, sealing material or the like are sanitized and the food product(s) are next removed from the casing, sealing material or the like and one or more further lethality treatments are applied to kill any pathogens that might somehow have reached the surface of the food product(s). After the one or more lethality treatments, the received food product(s) are transported, for example, by conveyor through a food produce delivery area, to each of the separate food processing rooms for further food processing. In general, the food product(s) delivery areas through which the food product(s) pass between the final lethality treatments and the food processing rooms are also treated as secure or sterile regions such that any source of contamination is excluded from such regions. In various exemplary embodiments, the food product(s) pass from the delivery area, which is at a first pressure, through a delivery opening into a particular food processing room, which is maintained at a higher air pressure, such that air moves unidirectionally through the delivery opening in the direction opposite that of the food product(s) as they enter that food processing room. In various exemplary embodiments of food processing facilities, systems and methods according to this invention, once in a given food processing room, the food product(s) is processed and immediately packaged for transport out of the food processing facility while in that food processing room. The packaged food product(s) is then transported, for example, by conveyor, out of the higher air pressure food processing room into a second common area. Because the food processing room is also at a higher pressure than this second common area, air constantly moves unidirectionally through the exit opening in the direction of movement of the packaged food product(s). The packaged food product(s) from the various food processing rooms are then inspected for package integrity, further packaged, held under refrigerated conditions and prepared for transport to a customer for sale to the ultimate consumer. Any inspected package which lacks integrity is rerouted for another lethality treatment before repackaging in the food processing room from which it came. In various exemplary embodiments of food processing facilities, systems and methods according to this invention, should one of the isolated food processing rooms become contaminated, that room can be shut down and sterilized without affecting the operation of other food processing rooms. Furthermore, because all of the food product processed in that food processing room were separately packaged and identified while in that food processing room, the food product from that food processing room is inherently distinguishable from the food products processed in the other food processing rooms, and thus can be separately recalled or otherwise destroyed. If contaminated, that food processing room can then be sterilized using a combination of one or both of heat and chemical sanitizers. In addition, the drain for that room can be separately plugged and flushed for sanitizing reasons without affecting the operation of the drain lines of the other food processing rooms. In various exemplary embodiments of food processing facilities, systems and methods according to this invention, when repair or maintenance of the machinery in a given food processing room is required, maintenance personnel entering that food processing room must also be wearing secure area uniforms and go through the same sanitary procedures as the operators working in that food processing room. In various exemplary embodiments, if the maintenance personnel are coming from another food processing room, those maintenance personnel desirably don new, sanitary food processing uniforms. In various exemplary embodiments of food processing facilities, systems and methods according to this invention, each of the food processing rooms contains all of the supplies and tools necessary to perform common maintenance procedures and to repair the food processing equipment due to common or expected faults. Accordingly, for simple or common repairs or maintenance, the maintenance personnel do not need to carry any tools or supplies into that food processing room. If more unusual repairs or maintenance needs to be made, any parts, supplies or tools that must be carried into that food processing room by the maintenance personnel are desirably first subjected to an alcohol wash or other appropriate cleaning and/or sterilizing procedure before those parts, supplies and/or tools are carried by the maintenance personnel into that food processing room. These and other individual features and advantages which may be separately incorporated in various exemplary embodiments of systems and methods according to this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the systems, methods and facilities for processing food according to this invention. | 20040406 | 20100504 | 20051110 | 94388.0 | 2 | ALEXANDER, REGINALD | CLEAN ROOM FOOD PROCESSING SYSTEMS, METHODS AND STRUCTURES | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,819,035 | ACCEPTED | Safety harness | A preferred embodiment safety harness includes two straps that are operatively connected at a juncture and a D-ring proximate the juncture. A retrofittable, removable back panel padding is configured and arranged to accommodate the straps and the D-ring to aid in the comfort in donning the safety harness. | 1. A safety harness, comprising: a) a first strap and a second strap operatively connected at a juncture; b) a D-ring operatively connected to said straps proximate said juncture; and c) a removable padding configured and arranged to operatively connect to said straps proximate said juncture, said padding accommodating said D-ring without interfering with operation of said D-ring, said straps and said D-ring being movable and adjustable independently of said padding, said padding being retrofittable. 2. The safety harness of claim 1, further comprising a hip strap, said removable padding being configured and arranged to operatively connect to said hip strap. 3. The safety harness of claim 1, further comprising a panel operatively connected to said padding proximate each of said straps, said panel forming a channel proximate each of said straps in which each of said straps is slidably secured between said panel and said padding, said panel releasably securing each of said straps within each of said channels. 4. The safety harness of claim 3, further comprising a material operatively connected to said padding within each said channel, said material providing friction against each of said straps thereby assisting in keeping said padding in place along each of said straps. 5. The safety harness of claim 1, further comprising a first panel and a second panel operatively connected to said padding proximate each of said straps, said first panel being releasably securable to said second panel, said panels forming a channel proximate each of said straps in which each of said straps is slidably secured between said panels and said padding, said panels releasably securing each of said straps within each said channel. 6. The safety harness of claim 5, wherein said first panel is operatively connected to a first side of said padding and said second panel is operatively connected to a second side of said padding, said panels being releasably securable proximate a middle portion of said padding. 7. The safety harness of claim 3, further comprising a hook and loop fastener operatively connected to said panel, said hook and loop fastener releasably securing said panel to said padding, said straps being slidably and releasably secured within said channel. 8. The safety harness of claim 3, further comprising a zipper operatively connected to said panel, said zipper releasably securing said panel to said padding thereby slidably and releasably securing said straps within said channel. 9. The safety harness of claim 8, further comprising a stop operatively connected to said padding proximate said zipper, said stop assisting in preventing said zipper from becoming unfastened. 10. The safety harness of claim 1, wherein said padding includes foam pads. 11. The safety harness of claim 10, further comprising air channels between said foam pads, said air channels allowing air to circulate between said foam pads. 12. The safety harness of claim 1, wherein said padding includes a 3-D fabric. 13. A safety harness, comprising: a) a first strap and a second strap operatively connected at a juncture, said first strap and said second strap cooperating to form four strap segments extending from said juncture; and b) a removable padding configured and arranged to operatively connect to said first strap and said second strap proximate said juncture, said padding including four pad segments proximate each of said four strap segments, said four pad segments extending outward from a back pad proximate said juncture, said four pad segments each including a channel in which each respective strap segment is slidably secured to said padding, said padding being retrofittable. 14. The safety harness of claim 13, further comprising a hip strap, said removable padding including a fifth pad segment configured and arranged to operatively connect to said hip strap, said fifth pad segment including a channel in which said hip strap is slidably secured to said padding. 15. The safety harness of claim 13, further comprising a panel operatively connected to each of said four pad segments, said panel forming said channel in which each respective strap segment is slidably secured between said panel and said padding, said panel releasably securing each respective strap segment within said channel. 16. The safety harness of claim 13, further comprising a first panel and a second panel operatively connected to each of said four pad segments, said first panel being releasably securable to said second panel, said panels forming a channel in which each respective strap segment is slidably secured between said panels and said padding, said panels releasably securing each respective strap within said channel. 17. The safety harness of claim 16, wherein said first panel is operatively connected to a first side of said padding and said second panel is operatively connected to a second side of said padding, said panels being releasably securable proximate a middle portion of said padding. 18. The safety harness of claim 15, further comprising a zipper operatively connected to each said panel, said zipper releasably securing said panel thereby slidably and releasably securing each said four strap segments within each said respective channel. 19. The safety harness of claim 15, further comprising a material operatively connected to said padding within said channel, said material providing friction against said straps thereby assisting in keeping said padding in place along said straps. 20. A retrofittable, removable padding for use with a safety harness donned by a worker, the safety harness including a first strap and a second strap operatively connected at a juncture, the safety harness including a D-ring operatively connected to the straps proximate the juncture, comprising: a) a padding configured and arranged to operatively connect to the straps of the safety harness proximate the juncture, the padding accommodating the D-ring without interfering with operation of the D-ring, the straps and the D-ring being movable and adjustable independently of the padding, the padding being positioned between the worker and the straps of the safety harness; and b) a panel operatively connected to said padding proximate each of the straps, said panel forming a channel proximate each of the straps in which each of the straps is slidably secured between said panel and said padding, said panel having an open position and a closed position, said open position providing access to said channel, said closed position releasably securing each of the straps within each said channel between said panel and said padding, wherein each of the straps is removable from said padding when each respective said panel is in said open position. 21. The padding of claim 20, further comprising a zipper operatively connected to said panel, said zipper releasably securing said panel to said padding thereby slidably and releasably securing the straps within said channel. 22. A method of retrofitting a removable padding onto a safety harness donned by a worker, comprising: a) providing a safety harness including a first strap and a second strap operatively connected at a juncture, the safety harness including a D-ring operatively connected to the straps proximate the juncture; b) providing a removable padding configured and arranged to operatively connect to the straps of the safety harness proximate the juncture; and c) connecting the padding to the straps of the safety harness, the padding accommodating the D-ring without interfering with operation of the D-ring, the straps and the D-ring being movable and adjustable independently of the padding, the padding being connected to the straps of the safety harness by placing the straps of the safety harness within channels of the padding and securing the straps of the safety harness within the channels of the padding, the padding having an open position and a closed position, said open position providing access to said channels, said closed position releasably securing the straps within said channels of said padding, wherein said open position allows the straps to be removed from said padding. 23. The method of claim 22, wherein the straps of the safety harness are secured within the channels of the padding by operatively connecting a panel to the padding, the straps being slidably secured between the panel and the padding. 24. The method of claim 22, wherein the straps of the safety harness are secured within the channels of the padding by overlapping and securing panels together over the straps, the straps being slidably secured between the panel and the padding. 25. The method of claim 22, further comprising donning the safety harness, wherein the padding is between the worker and the straps of the safety harness. 26. The method of claim 25, further comprising: a) removing the safety harness; and b) removing the padding from the safety harness. | This application claims the benefit of U.S. Provisional Application No. 60/500,597, filed Sep. 5, 2003. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety harness and components thereof. 2. Description of the Prior Art Various occupations place people in precarious positions at relatively dangerous heights thereby creating a need for fall-arresting safety apparatus. Among other things, such apparatus usually include a safety line interconnected between a support structure and a person working in proximity to the support structure. The safety line is typically secured to a full-body safety harness worn by the worker. Obviously, such a harness must be designed to remain secure about the worker in the event of a fall. In addition, the harness should arrest a person's fall in as safe a manner as possible, placing a minimal amount of strain on the person's body. Yet another design consideration is to minimize the extent to which people may consider the harness uncomfortable and/or cumbersome. Fall-arresting harnesses have been made with various features to enhance user comfort and/or more evenly distribute or absorb impact associated with a fall. However, these features must not compromise the effectiveness of the harness. In other words, there is a need for a safety harness that strikes an appropriate balance between user safety and user comfort. SUMMARY OF THE INVENTION A preferred embodiment safety harness includes a first strap and a second strap operatively connected at a juncture, a D-ring operatively connected to the straps proximate the juncture, and a removable padding configured and arranged to operatively connect to the straps proximate the juncture. The padding accommodates the D-ring without interfering with operation of the D-ring. The straps and the D-ring are movable and adjustable independently of the padding, and the padding is retrofittable. A preferred embodiment safety harness includes a first strap and a second strap operatively connected at a juncture and a removable padding configured and arranged to operatively connect to the first strap and the second strap proximate the juncture. The first strap and the second strap cooperate to form four strap segments extending from the juncture. The padding includes four pad segments proximate each of the four strap segments. The four pad segments extend outward from a back pad proximate the juncture. The four pad segments each including a channel in which each respective strap segment is slidably secured to the padding. The padding is retrofittable. A preferred embodiment retrofittable, removable padding for use with a safety harness donned by a worker includes a padding and a panel. The safety harness includes a first strap and a second strap operatively connected at a juncture and a D-ring operatively connected to the straps proximate the juncture. The padding is configured and arranged to operatively connect to the straps of the safety harness proximate the juncture. The padding accommodates the D-ring without interfering with operation of the D-ring, and the straps and the D-ring are movable and adjustable independently of the padding. The padding is positioned between the worker and the straps of the safety harness. The panel is operatively connected to the padding proximate each of the straps, and the panel forms a channel proximate each of the straps in which each of the straps is slidably secured between the panel and the padding. The panel has an open position and a closed position. The open position provides access to the channel, and the closed position releasably secures each of the straps within each channel between the panel and the padding. Each of the straps is removable from the padding when each respective panel is in the open position. A preferred embodiment method of retrofitting a removable padding onto a safety harness donned by a worker includes providing a safety harness and providing a removable padding. The safety harness includes a first strap and a second strap operatively connected at a juncture and a D-ring operatively connected to the straps proximate the juncture. The removable padding is configured and arranged to operatively connect to the straps of the safety harness proximate the juncture. The padding is connected to the straps of the safety harness. The padding accommodates the D-ring without interfering with operation of the D-ring. The straps and the D-ring are movable and adjustable independently of the padding. The padding is connected to the straps of the safety harness by placing the straps of the safety harness within channels of the padding and securing the straps of the safety harness within the channels of the padding. The padding has an open position and a closed position. The open position provides access to the channels. The closed position releasably secures the straps within the channels of the padding. The open position allows the straps to be removed from the padding. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a removable back panel padding for use with a safety harness constructed according to the principles of the present invention; FIG. 2 is a front view of the removable back panel padding shown in FIG. 1 with a safety harness; FIG. 3 is a back view of the removable back panel padding shown in FIG. 1; FIG. 4 is a side view of the removable back panel padding shown in FIG. 1; FIG. 5 is a front view of another embodiment removable back panel padding for use with a safety harness including a hip belt constructed according to the principles of the present invention; FIG. 6 is a front view of the removable back panel padding shown in FIG. 5 with a safety harness including a hip belt; FIG. 7 is a cross-sectional view of a fabric of the removable back panel padding shown in FIGS. 1 and 5; FIG. 8 is a perspective view of a safety harness including a removable back panel padding constructed according to the principles of the present invention; FIG. 9 is a front view of a partial pad of another embodiment removable back panel padding for use with a safety harness constructed according to the principles of the present invention; FIG. 10 is a front view of a partial pad of another embodiment removable back panel padding for use with a safety harness constructed according to the principles of the present invention; FIG. 11 is a front view of a partial pad of another embodiment removable back panel padding for use with a safety harness constructed according to the principles of the present invention; and FIG. 12 is a perspective view of another safety harness including another embodiment removable back panel padding constructed according to the principles of the present invention. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Preferred embodiment safety harnesses and components thereof constructed according to the principles of the present invention are shown in the drawings, wherein like numerals represent like components throughout the drawings. A preferred embodiment retrofittable and removable back panel padding 100 for use with a safety harness 124 is shown in FIGS. 1-4. With reference to FIGS. 1 and 2, the removable back panel padding 100 includes a left shoulder pad 101, a right shoulder pad 102, a left waist pad 103, a right waist pad 104, and a back pad 105. The back pad 105 interconnects the pads 101, 102, 103, and 104 to form the padding 100. A binding 106 is sewn around the perimeter of the padding 100. Although any suitable material well known in the art may be used, the binding 106 is preferably one piece soft polyester grosgrain that is folded over from the front side to the back side of the padding 100 and is sewn through the padding 100 proximate each edge of the binding 106 to fasten each side of the binding 106 to the padding 100. The binding 106 finishes the edges of the padding 100 and connects the layers of material used in the padding 100. The left shoulder pad 101 includes a fabric panel 107 on the left side and a fabric panel 108 on the right side. Each panel 107 and 108 is secured by the binding 106 along one side and along the top end. The opposite sides of the panels 107 and 108, which are each proximate the middle of the pad 101, are folded over and sewn at stitching 145a and 145b to create flaps 107a and 108a, respectively. Stitching 145a and 145b are shown as dashed lines. The flaps 107a and 108a provide two edges along which each side of a zipper 109 may be sewn. In other words, the panels 107 and 108 are releasably interconnected proximate the middle of the pad 101 by the zipper 109. A channel 145 in which a left shoulder strap may be slidably and releasably secured is created under the zipper 109 and flaps 107a and 108a and above the pad 101. In other words, the stitching 145a and 145b define the approximate width of the channel 145. A zipper pull 109a is used to fasten and to open the zipper 109 when the left shoulder strap is to be secured within and removed from the channel in the pad 101. The right shoulder pad 102 includes a fabric panel 111 on the left side and a fabric panel 112 on the right side. Each panel 111 and 112 is secured by the binding 106 along one side and along the top end. The opposite sides of the panels 111 and 112, which are each proximate the middle of the pad 102, are folded over and sewn at stitching 146a and 146b to create flaps 111a and 112a, respectively. Stitching 146a and 146b are shown as dashed lines. The flaps 111a and 112a provide two edges along which each side of a zipper 113 may be sewn. In other words, the panels 111 and 112 are releasably interconnected proximate the middle of the pad 102 by the zipper 113. A channel 146 in which a right shoulder strap may be slidably and releasably secured is created under the zipper 113 and flaps 111a and 112a and above the pad 102. In other words, the stitching 146a and 146b define the approximate width of the channel 146. A zipper pull 113a is used to fasten and to open the zipper 113 when the right shoulder strap is to be secured within and removed from the channel in the pad 102. The left waist pad 103 includes a fabric panel 115 on the left side and a fabric panel 116 on the right side. Each panel 115 and 116 is secured by the binding 106 along one side and along the bottom end. The opposite sides of the panels 115 and 116, which are each proximate the middle of the pad 103, are folded over and sewn at stitching 147a and 147b to create flaps 115a and 116a, respectively. Stitching 147a and 147b are shown as dashed lines. The flaps 115a and 116a provide two edges along which each side of a zipper 117 may be sewn. In other words, the panels 115 and 116 are releasably interconnected proximate the middle of the pad 103 by the zipper 117. A channel 147 in which a left leg strap may be slidably and releasably secured is created under the zipper 117 and 115a and 116a and above the pad 103. In other words, the stitching 147a and 147b define the approximate width of the channel 147. A zipper pull 117a is used to fasten and to open the zipper 117 when the left leg strap is to be secured within and removed from the channel in the pad 103. The right waist pad 104 includes a fabric panel 119 on the left side and a fabric panel 120 on the right side. Each panel 119 and 120 is secured by the binding 106 along one side and along the bottom end. The opposite sides of the panels 119 and 120, which are each proximate the middle of the pad 104, are folded over and sewn to create flaps 119a and 120a, respectively. The flaps 119a and 120a provide two edges along which each side of a zipper 121 may be sewn. In other words, the panels 119 and 120 are releasably interconnected proximate the middle of the pad 104 by the zipper 121. A channel 122 in which a right leg strap may be slidably and releasably secured is created under the zipper 121 flaps 119a and 120a and above the pad 104. Flaps 119a and 120a are opened to expose channel 122, which is shown in an opened position. Channel 122 is similar to channels 145, 146, and 147, which are shown in a closed position because the corresponding flaps are releasably interconnected and thereby closed. A zipper pull 121a is used to fasten and to open the zipper 121 when the right leg strap is to be secured within and removed from the channel in the pad 104. As stated previously, the back pad 105 interconnects the pads 101, 102, 103, and 104 to form the padding 100, which is configured and arranged to engage a safety harness 124. The safety harness 124 includes a first strap 125 and a second strap 126, which overlap at a juncture and criss-cross in divergent fashion proximate the back of the safety harness 124, as shown in FIG. 2. The first strap 125 includes a left shoulder strap 125a and a right leg strap 125b, which are operatively connected proximate the juncture. The second strap 126 includes a right shoulder strap 126a and a left leg strap 126b, which are operatively connected proximate the juncture. In other words, four strap segments extend from proximate the juncture. The safety harness 124 also includes a chest strap 127, which includes a first strap 127a and a second strap 127b. The back pad 105 also accommodates a back pad assembly 128 of the safety harness 124 proximate the juncture. The back pad assembly 128 includes a D-ring 129, which is operatively connected to the straps proximate the juncture. With reference to FIGS. 3 and 4, the back side of the padding 100 preferably includes foam pads 130, air channels 131, and 3D fabric 132. The 3D fabric 132, which is very breathable, is used as a base panel for the padding 100, and the foam pads 130 are cut and positioned on the 3D fabric 132. The 3D fabric 132 is discussed in more detail below. An example of a 3D fabric that may be used is DRI-LEX™ AERO-SPACER™ lining, which is covered by U.S. Pat. No. 5,746,013 incorporated by reference herein, by Faytex Corp. of Weymouth, Mass. Other suitable types of 3D fabric well known in the art may also be used. The foam pads 130 are preferably {fraction (3/4)} inch thick EVA foam. On pads 101 and 102, there are preferably foam pads 130 proximate each end, proximate a middle section of each pad 101 and 102, and spanning from pad 101 to 102 along the binding 106 and into a top portion of pad 105. Air channels 131 separate the foam pads 130 between these sections and are preferably {fraction (1/4)} inch wide. As shown in FIG. 4, there is an air channel 131 at the top of each shoulder and near each collarbone of the user. There are preferably foam pads 130 on the pads 103 and 104 and extending partially into the pad 105. 3D fabric is used in the remaining portion of the back pad 105 and between the pads 103 and 104. The air channels 131 and the 3D fabric allow air to flow through the padding 100 so that the padding 100 does not get as warm for the user. A cross-section of a portion of a preferred construction of pad 105 is shown in FIG. 7. Pad 105 preferably includes two layers of 3D fabric 132 with a foam stiffener 135 in between the two layers of 3D fabric 132. The 3D fabric 132 preferably includes a first outer layer 133a, a middle layer 134, and a second outer layer 133b. The first outer layer 133a is preferably made of a hydrophobic material such as a polyester mesh material. The second outer layer 133b is preferably made of a hydrophilic material such as nylon. The middle layer 134 interconnects the outer layers 133a and 133b and is an air chamber preferably made of monofilament yarns interknitted with both inner and outer knit layers in a known manner such as with the use of the well-known Raschel tricot knitting machine. The monofilament yarns are preferably a hydrophobic material such as a polyester material. The middle layer 134 allows air to flow through the fabric thereby making the fabric more comfortable to don. In the preferred embodiment, the second outer layers 133b are placed proximate the foam stiffener 135 and the first outer layers 133a are placed proximate the outer surfaces of the pad 105. This arrangement allows moisture to be wicked away from the outer surface of the fabric and drawn toward the center of the fabric also aiding in the comfort of the fabric. The 3D fabric 132 allows moisture to be drawn away from the worker donning the padding 100 and allows air to circulate through the fabric thereby assisting in cooling the worker. The foam stiffener 135 is optional and is preferably used in the pad 105 to provide some support for the back pad assembly 128. A stiffener may also be used in the shoulder area to provide some structure. In operation, the zippers 109, 113, 117, and 121 are opened to expose the channels, which are preferably approximately 2 inches wide to accommodate the straps 125 and 126 of the safety harness 124. The safety harness 124 is placed on top of the padding 100 so that the juncture and the back pad assembly 128 are placed proximate the center of the back pad 105. The left shoulder strap 125a is placed within the channel on pad 101, and zipper 109 is fastened over the top of the left shoulder strap 125a. The right shoulder strap 126a is placed within the channel on pad 102, and zipper 113 is fastened over the top of the right shoulder strap 126a. The left leg strap 126b is placed within the channel on pad 103, and zipper 117 is fastened over the top of the left leg strap 126b. The right leg strap 125b is placed within the channel 122 on pad 104, as shown in FIG. 2, and zipper 121 is fastened over the top of the right leg strap 125b. Securing the straps 125 and 126 within the channels may be performed in any order. The padding 100 has four pad segments corresponding with the four strap segments, and the padding 100 accommodates the back pad assembly 128 and the D-ring 129 without interfering with operation of the D-ring 129. The straps 125 and 126 and the D-ring 129 are movable and adjustable within the channels of the padding 100, independently of the padding 100. In other words, the straps 125 and 126 are slidably secured within the channels by the padding 100. The back pad assembly 128 may be adjusted along the straps 125 and 126 to the proper position for the user with or without removing the safety harness 124 from the padding 100. FIGS. 5 and 6 show another preferred embodiment removable back panel padding 200. Like the padding 100, the padding 200 includes a left shoulder pad 201, a right shoulder pad 202, a left waist pad 203, a right waist pad 204, and a back pad 205. The back pad 205 interconnects the pads 201, 202, 203, and 204. In addition, the padding 200 includes a hip pad 210 extending along the bottom of the padding 200 and including a left end 210a and a right end 210b. The hip pad 210 interconnects pads 203 and 204 and creates an opening 223 therebetween. A binding 206 is sewn around the perimeter of the padding 200 and within the opening 223. The binding 206 is one piece that is folded over from the front side to the back side of the padding 200 and is sewn through the padding 200 proximate each edge of the binding 206 to fasten each side of the binding 206 to the padding 200. The binding 206 finishes the edges of the padding 200 and connects the layers of fabric used in the padding 200. As with padding 100, the pads 201, 202, 203, and 204 of padding 200 each include fabric panels, flaps, and zippers to form channels in which straps of a safety harness may be secured. The hip pad 210 also includes a fabric panel 214 proximate the top of the pad 210 and below the opening 223 and a fabric panel 218 proximate the bottom of the pad 210. The panel 214 is secured by the binding 206 along the top side and the panel 218 is secured by the binding 206 along the bottom side. The opposite sides of the panels 214 and 218, which are each proximate the middle of the pad 210, are folded over and sewn at stitching 248a and 248b to create flaps 214a and 218a, respectively. Stitching 248a and 248b are shown as dashed lines. The flaps 214a and 218a provide two edges along which each side of a zipper 236 may be sewn. In other words, the panels 214 and 218 are releasably interconnected proximate the middle of the pad 210 by the zipper 236. A channel 240 in which a hip strap 241 may be slidably and releasably secured is created under the zipper 236 and flaps 214a and 218a and above the pad 210. In other words, the stitching 248a and 248b define the approximate width of the channel 240. A zipper pull 236a is used to fasten and to open the zipper 236 when the hip strap 241 is to be secured within and removed from the channel 240 in the pad 210. Optionally, the padding 200 may also include keepers 237a and 237b. Keepers 237a and 237b are preferably made of VELCRO® hook and loop fasteners sewn or otherwise fastened proximate the left end 210a and the right end 210b, respectively, of the pad 210. The keepers 237a and 237b secure portions of the hip strap 241 proximate the ends 210a and 210b of the pad 210. Keepers 237a and 237b may also be used with padding 100. Preferably, the zippers include locking zipper pulls. Another option is to include a zipper stop 238, shown in FIG. 5. The zipper stop 238 is preferably made of a VELCRO® loop sewn or otherwise fastened to the pad 202 proximate the zipper pull 213a when the zipper 213 is closed. The zipper stop 238 helps keep the zipper pull 213a from sliding along the zipper 213 thereby opening and unfastening the zipper 213 and releasing the harness strap. Although only one zipper stop 238 is shown proximate the zipper pull 213a on pad 202, it is recognized that a zipper stop 238 may be placed proximate any of the zipper pulls. In addition, a zipper stop 238 may be used with both the paddings 100 and 200. Alternatively, rather than using zippers with any of the embodiments, VELCRO®, laces, buckles, snaps, or other suitable fasteners well known in the art could be used to secure the padding about the harness straps. Another option is to include a holder 239, shown in FIG. 5, to which the end of a device such as a lanyard may be releasably connected when not in use. For example, with a lanyard, one end is connected to a D-ring on the back pad of a harness and the other end that would normally be connected to a lifeline could be connected to the holder 239. This would keep the loose end from catching on an object or even tripping the user when not connected to a lifeline. The holder 239 is preferably made of a VELCRO® loop sewn or otherwise fastened to the padding 200 in a location in which it will be relatively easy to use. The holder 239 is shown proximate the right hip region of the user but may be placed in any location on the padding 200. The holder 239 may also be used with padding 100. As shown in FIG. 6, the padding 200 is configured and arranged to engage a safety harness 224 including straps 225 and 226 and a hip belt 241. The safety harness 224 includes a first strap 225 and a second strap 226, which overlap at a juncture and criss-cross in divergent fashion proximate the back of the safety harness 224, as shown in FIG. 6. The first strap 225 includes a left shoulder strap 225a and a right leg strap 225b, which are operatively connected proximate the juncture. The second strap 226 includes a right shoulder strap 226a and a left leg strap 226b, which are operatively connected proximate the juncture. In other words, four strap segments extend from proximate the juncture. Right leg strap 225b is shown within channel 222 in FIG. 6. The safety harness 224 also includes a hip strap 241, which extends across the back of the user proximate the hip area. A back pad assembly 228 having a D-ring 229 is also included in the safety harness 224. The D-ring 229 is operatively connected to the straps 225 and 225 proximate the juncture. In operation, the zippers are opened to expose the channels. The safety harness 224 is placed on top of the padding 200 so that the back pad assembly 228 is placed proximate the center of the back pad 205. The left shoulder strap 225a is placed within the channel on pad 201, and the zipper is fastened over the top of the left shoulder strap 225a. The right shoulder strap 226a is placed within the channel on pad 202, and the zipper 213 is fastened over the top of the right shoulder strap 226a. The left leg strap 226b is placed within the channel on pad 203, and the zipper is fastened over the top of the left leg strap 226b. The right leg strap 225b is placed within the channel 222 on pad 204, as shown in FIG. 6, and the zipper is fastened over the top of the right leg strap 225b. The hip strap 241 is then placed within channel 240 on pad 210, and the zipper 236 is fastened over the top of the hip strap 241. Securing the straps 225, 226, and 241 within the channels may be performed in any order. The padding 200 has four pad segments corresponding with the four strap segments and a fifth pad segment corresponding with the hip strap 241. The padding 200 accommodates the back pad assembly 228 and the D-ring 229 without interfering with operation of the D-ring 229. The straps 225, 226, and 241 and the D-ring 229 are movable and adjustable within the channels of the padding 200, independently of the padding 200. In other words, the straps 225, 226, and 241 are slidably secured within the channels by the padding 200. The back pad assembly 228 may be adjusted along the straps 225 and 226 to the proper position for the user with or without removing the safety harness 224 from the padding 200. Prior art padding on the back of a safety harness, such as the EXOFIT™ harness model number 1107975 by DBI/SALA, is fixedly attached to the harness. The straps and the back pad and/or D-ring assembly are fixedly attached to the padding and are not adjustable or movable independently from the padding. Because the pack pad and/or D-ring assembly should be in a certain position on the user's back, this type of harness may not easily accommodate different users. In addition, when the D-ring is fixed, the D-ring may not readily slide upward during a fall thereby resulting in the user tilting forward rather than being in an upright position from a fall. FIG. 8 shows another embodiment removable back panel padding 300 engaging a safety harness 324 as a safety harness would be donned by a worker. The safety harness 324 includes a left shoulder strap 325a, a right shoulder strap 326a, a left leg strap 326b, a right leg strap 325b, and a chest strap 327. The padding 300 is configured and arranged similar to the padding 100 and the safety harness 324 is configured and arranged similar to the safety harness 124, which are discussed in greater detail above. The removable back panel padding 300 includes a left shoulder pad 301, a right shoulder pad 302, a left waist pad 303, a right waist pad 304, and a back pad 305. The back pad 305 interconnects the pads 301, 302, 303, and 304 to form the padding 300. The back pad 305 is configured and arranged to accommodate a back pad assembly 328 and a D-ring 329 of the safety harness 324. The back of the padding 300 includes foam pads 330 to aid in the comfort in donning the safety harness 324. A binding 306 is sewn around the perimeter of the padding 300. Although any suitable material well known in the art may be used, the binding 306 is preferably one piece soft polyester grosgrain that is folded over from the front side to the back side of the padding 300 and is sewn through the padding 300 proximate each edge of the binding 306 to fasten each side of the binding 306 to the padding 300. The binding 306 finishes the edges of the padding 300 and connects the layers of material used in the padding 300. Optionally, a strap 339 may be used to interconnect the pads 303 and 304 to assist in keeping the leg straps 325b and 326b from spreading too far apart. Preferably, the strap 339 is made of an elastic material to aid in the comfort in donning the harness. The left shoulder pad 301 includes a fabric panel 307 on the left side and a fabric panel 308 on the right side. Each panel 307 and 308 is secured by the binding 306 along one side and along the top end. The opposite sides of the panels 307 and 308, which are each proximate the middle of the pad 301, are folded over and sewn to create flaps 307a and 308a, respectively. The flaps 307a and 308a provide two edges along which each side of a zipper 309 may be sewn. In other words, the panels 307 and 308 are interconnected proximate the middle of the pad 301 by the zipper 309. A channel 310 in which the left shoulder strap 325a of the safety harness 324 may be secured is created under the zipper 309 and flaps 307a and 308a and above the pad 301. Within at least a portion of the channel 310 is an optional material 315, which is preferably a rubber-like material, operatively connected to the padding 300. The material 315 provides a frictional surface against which the left shoulder strap 325a contacts or rubs to assist in keeping the left shoulder pad 301 in place along the left shoulder strap 325a. Preferably, such rubber-like material is placed within each channel proximate the padding to keep the straps of the safety harness in place on the padding. A zipper pull 309a is used to fasten and to open the zipper 309 when the left shoulder strap is to be secured within and removed from the channel 310 in the pad 301. The pads 302, 303, and 304 are similarly configured and arranged. A channel 322 is shown in pad 304 in which right leg strap 325b is placed. Optional zipper stops 338 may be secured to each of the pads 301, 302, 303, and 304 proximate each of the zipper pulls when the zippers are closed. The zipper stops 338 are preferably made of a VELCRO® loop sewn or otherwise fastened to the pads. The zipper stops 338 help keep the zipper pulls from sliding along the zippers thereby opening the zippers and releasing the harness straps. This is shown on pads 302 and 303 in FIG. 8. Alternatively, rather than using zippers, VELCRO®, laces, buckles, snaps, or other suitable fasteners well known in the art could be used to secure the padding about the harness straps. The removable back panel padding 100, 200, and 300 may be configured and arranged to retrofit existing safety harnesses with padding to increase the comfort in wearing the existing safety harnesses, and the removable back panel padding 100, 200, and 300 may be removed for laundering after use. The padding 100, 200, and 300 is positioned between the worker and the straps of the safety harness. The straps of the harness are engaged within the channels of the padding and may slide within the channels, and the back pad and/or D-ring assembly is not so engaged by the padding. In other words, the padding may slide along the lengths of the straps. Because the removable back panel padding 100, 200, and 300 are not fixedly attached to the safety harness, the back pad and/or D-ring assembly may be readily adjusted to the proper position for each user. The back pad and/or D-ring assembly is adjustable and movable independently from the padding. The back pad and/or D-ring may be moved along the lengths of the straps as is well known in the art, and the padding may be adjusted accordingly along the lengths of the straps by sliding the straps through the channels, with the back pad and/or D-ring assembly proximate the back pad 105, 205, and 305. In other words, the straps may be pulled through the channels to obtain excess material proximate the back pad 105, 205, and 305 above or below the back pad and/or D-ring assembly, depending upon the direction the back pad and/or D-ring is to be moved. Then, the back pad and/or D-ring may be adjusted as is well known in the art in the desired direction, and the excess material opposite the direction of movement of the back pad and/or D-ring may be pulled through the channels to take up the slack in the straps. Preferably, there is no slack in the straps proximate the back pad and/or D-ring assembly and the back pad 105, 205, and 305 when worn by the user. Alternatively, the harness may be removed from the padding, the back pad and/or D-ring assembly may be adjusted, and the padding may be connected to the harness again. In addition, because the D-ring is not fixedly attached to the padding, the D-ring may readily slide upward during a fall thereby resulting in the user being in an upright position from a fall, which also adds to the comfort in donning the harness. Further, shoulder strap padding or leg strap padding similarly constructed for easy attachment and removal could be used with an existing safety harness. In addition, rather than using zippers in any of the embodiments, VELCRO®, laces, buckles, snaps, or other suitable fasteners well known in the art could be used to secure the padding about the harness straps. FIG. 9 shows a pad 401 having a first panel 402a on one side of the pad 401 and a second panel 402b on the other side of the pad 401. Each panel 402a and 402b includes grommets 403 through which laces 404 are threaded. A channel 405 is formed between the laces 404 and the pad 401, and the safety harness may be secured within the channel 405. FIG. 11 shows a pad 601 having a first strap 602a on one side of the pad 601 and a second strap 602b on the other side of the pad 601. A snap or a buckle 603 interconnects the straps 602a and 602b. A channel 605 is formed between the straps 602a and 602b and the pad 601, and the safety harness may be secured within the channel 605. Further, rather than having two panels and two flaps, a single panel and a single flap may be used for securing each safety harness strap. The panel could be securable and releasable proximate one side of the pad with a channel underneath the panel. FIG. 10 shows a pad 501 having a panel 502 fixedly attached to one side of the pad 501. The other side of the pad 501 has a piece of VELCRO® 503a configured and arranged to mate with a mating piece of VELCRO® 503b on the panel 502. A channel 505 is formed between the panel 502 and the pad 501, and the safety harness may be secured within the channel 505. Also, a strap with a snap or a buckle, VELCRO®, a zipper, or snaps could be used to secure each of the straps of the safety harness to the padding. It is recognized that these embodiments are not exhaustive and that other embodiments are within the scope of the present invention. Although it is preferred that the removable back panel padding include padding extending over the shoulders of the person donning the harness, this extended padding is not necessary for the present invention. As shown in FIG. 12, a removable back panel padding 700 may span an area proximate a back pad and D-ring assembly 728, which is sufficient to secure the straps 725a, 725b, 726a, and 726b of a safety harness to the padding 700 without interfering with the operation of the back pad and D-ring assembly 728. The padding 700 includes a left shoulder pad 701, a right shoulder pad 702, a left waist pad 703, a right waist pad 704, and a back pad 705. The back pad 705 interconnects the pads 701, 702, 703, and 704 to form the padding 700. The back pad 705 is configured and arranged to accommodate the back pad and D-ring assembly 728 of the safety harness. A binding 706 is sewn around the perimeter of the padding 700. The left shoulder pad 701 includes a strap engaging member 707, which is preferably an elongate piece of pile 707a and a mating elongate piece of hook 707b. The pile 707a and the hook 707b are each fastened at one end to the pad, at opposite sides of the pad 701, and extend toward a middle portion of the pad 701. The opposite, unfastened ends of the pile 707a and the hook 707b overlap and mate to secure the strap engaging member 707 in a closed position. The strap engaging member 707 is in an open position when the pile 707a and the hook 707b are not mating to engage one another. Strap engaging member 707 is shown in the open position. A channel 711 is defined proximate the pad 701 between the fastened ends of the pile 707a and the hook 707b. When the strap engaging member 707 is in a closed position, the channel 711 is further defined between the pad 701 and the strap engaging member 707. The right shoulder pad 702 includes a strap engaging member 708, which is preferably an elongate piece of pile 708a and a mating elongate piece of hook 708b. The pile 708a and the hook 708b are each fastened at one end to the pad, at opposite sides of the pad 702, and extend toward a middle portion of the pad 702. The opposite, unfastened ends of the pile 708a and the hook 708b overlap and mate to secure the strap engaging member 708 in a closed position. The strap engaging member 708 is in an open position when the pile 708a and the hook 708b are not mating to engage one another. Strap engaging member 708 is shown in the closed position. A channel 712 is defined proximate the pad 702 between the fastened ends of the pile 708a and the hook 708b. When the strap engaging member 708 is in a closed position, the channel 712 is further defined between the pad 702 and the strap engaging member 708. The left waist pad 703 includes a strap engaging member 709, which is preferably an elongate piece of pile 709a and a mating elongate piece of hook 709b. The pile 709a and the hook 709b are each fastened at one end to the pad, at opposite sides of the pad 703, and extend toward a middle portion of the pad 703. The opposite, unfastened ends of the pile 709a and the hook 709b overlap and mate to secure the strap engaging member 709 in a closed position. The strap engaging member 709 is in an open position when the pile 709a and the hook 709b are not mating to engage one another. A channel 713 is defined proximate the pad 703 between the fastened ends of the pile 709a and the hook 709b. When the strap engaging member 709 is in a closed position, the channel 713 is further defined between the pad 703 and the strap engaging member 709. The right waist pad 704 includes a strap engaging member 710, which is preferably an elongate piece of pile 710a and a mating elongate piece of hook 710b. The pile 710a and the hook 710b are each fastened at one end to the pad, at opposite sides of the pad 704, and extend toward a middle portion of the pad 704. The opposite, unfastened ends of the pile 710a and the hook 710b overlap and mate to secure the strap engaging member 710 in a closed position. The strap engaging member 710 is in an open position when the pile 710a and the hook 710b are not mating to engage one another. A channel 714 is defined proximate the pad 704 between the fastened ends of the pile 710a and the hook 710b. When the strap engaging member 710 is in a closed position, the channel 714 is further defined between the pad 704 and the strap engaging member 710. In operation, the strap engaging members 707, 708, 709, and 710 are each placed in the open position thereby providing access to the channels 711, 712, 713, and 714, respectively. The safety harness is placed on top of the padding 700. The back pad and D-ring assembly 728 is placed on top of the back pad 705, the left shoulder strap 725a is placed within the channel 711 on top of the pad 701, the right shoulder strap 726a is placed within the channel 712 on top of the pad 702, the left waist strap 726b is placed within the channel 713 on top of the pad 703, and the right waist strap 725b is placed within the channel 714 on top of the pad 704. The strap engaging members 707, 708, 709, and 710 are then placed in the closed position thereby securing each of the respective straps within the respective channels. The straps are slidably engaged within the channels, and the padding 700 does not interfere with the operation of the back pad and D-ring assembly 728. It is understood that any of these features may be interchanged among the different preferred embodiments to create variations thereof and such variations are within the scope of the present invention. The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a safety harness and components thereof. 2. Description of the Prior Art Various occupations place people in precarious positions at relatively dangerous heights thereby creating a need for fall-arresting safety apparatus. Among other things, such apparatus usually include a safety line interconnected between a support structure and a person working in proximity to the support structure. The safety line is typically secured to a full-body safety harness worn by the worker. Obviously, such a harness must be designed to remain secure about the worker in the event of a fall. In addition, the harness should arrest a person's fall in as safe a manner as possible, placing a minimal amount of strain on the person's body. Yet another design consideration is to minimize the extent to which people may consider the harness uncomfortable and/or cumbersome. Fall-arresting harnesses have been made with various features to enhance user comfort and/or more evenly distribute or absorb impact associated with a fall. However, these features must not compromise the effectiveness of the harness. In other words, there is a need for a safety harness that strikes an appropriate balance between user safety and user comfort. | <SOH> SUMMARY OF THE INVENTION <EOH>A preferred embodiment safety harness includes a first strap and a second strap operatively connected at a juncture, a D-ring operatively connected to the straps proximate the juncture, and a removable padding configured and arranged to operatively connect to the straps proximate the juncture. The padding accommodates the D-ring without interfering with operation of the D-ring. The straps and the D-ring are movable and adjustable independently of the padding, and the padding is retrofittable. A preferred embodiment safety harness includes a first strap and a second strap operatively connected at a juncture and a removable padding configured and arranged to operatively connect to the first strap and the second strap proximate the juncture. The first strap and the second strap cooperate to form four strap segments extending from the juncture. The padding includes four pad segments proximate each of the four strap segments. The four pad segments extend outward from a back pad proximate the juncture. The four pad segments each including a channel in which each respective strap segment is slidably secured to the padding. The padding is retrofittable. A preferred embodiment retrofittable, removable padding for use with a safety harness donned by a worker includes a padding and a panel. The safety harness includes a first strap and a second strap operatively connected at a juncture and a D-ring operatively connected to the straps proximate the juncture. The padding is configured and arranged to operatively connect to the straps of the safety harness proximate the juncture. The padding accommodates the D-ring without interfering with operation of the D-ring, and the straps and the D-ring are movable and adjustable independently of the padding. The padding is positioned between the worker and the straps of the safety harness. The panel is operatively connected to the padding proximate each of the straps, and the panel forms a channel proximate each of the straps in which each of the straps is slidably secured between the panel and the padding. The panel has an open position and a closed position. The open position provides access to the channel, and the closed position releasably secures each of the straps within each channel between the panel and the padding. Each of the straps is removable from the padding when each respective panel is in the open position. A preferred embodiment method of retrofitting a removable padding onto a safety harness donned by a worker includes providing a safety harness and providing a removable padding. The safety harness includes a first strap and a second strap operatively connected at a juncture and a D-ring operatively connected to the straps proximate the juncture. The removable padding is configured and arranged to operatively connect to the straps of the safety harness proximate the juncture. The padding is connected to the straps of the safety harness. The padding accommodates the D-ring without interfering with operation of the D-ring. The straps and the D-ring are movable and adjustable independently of the padding. The padding is connected to the straps of the safety harness by placing the straps of the safety harness within channels of the padding and securing the straps of the safety harness within the channels of the padding. The padding has an open position and a closed position. The open position provides access to the channels. The closed position releasably secures the straps within the channels of the padding. The open position allows the straps to be removed from the padding. | 20040406 | 20051206 | 20050331 | 92135.0 | 1 | THOMPSON, HUGH B | SAFETY HARNESS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,819,143 | ACCEPTED | METHOD OF MANUFACTURING SELF-ORDERED NANOCHANNEL-ARRAY AND METHOD OF MANUFACTURING NANODOT USING THE NANOCHANNEL-ARRAY | A method of manufacturing a nanochannel-array and a method of fabricating a nanodot using the nanochannel-array are provided. The nanochannel-array manufacturing method includes: performing first anodizing to form a first alumina layer having a channel array formed by a plurality of cavities on an aluminum substrate; etching the first alumina layer to a predetermined depth and forming a plurality of concave portions on the aluminum substrate, wherein each concave portion corresponds to the bottom of each channel of the first alumina layer; and performing second anodizing to form a second alumina layer having an array of a plurality of channels corresponding to the plurality of concave portions on the aluminum substrate. The array manufacturing method makes it possible to obtain finely ordered cavities and form nanoscale dots using the cavities. | 1. A method of manufacturing a nanodot based on a self-ordered nanochannel-array, the method comprising: performing first anodizing an aluminum substrate to form a first alumina layer having a channel array formed by a plurality of cavities; etching away the first alumina layer to form a plurality of concave portions on the aluminum substrate, wherein each concave portion corresponds to the bottom of each channel of the first alumina layer; performing second anodizing to form a second alumina layer having an array of a plurality of channels corresponding to the plurality of concave portions on the aluminum substrate; forming a mask layer on a processing object layer, wherein the processing object layer is formed on another substrate, transferring a profile of the channel arm of the second alumina layer to the mask layer through compression molding; and etching the mask layer so that the profile is transferred to the processing object layer. 2. A method of manufacturing a nanodot using a self-ordered template, the method comprising: performing a first anodizing to form a first alumina layer having an array of a plurality of channels on a template containing an aluminum layer; etching the first alumina layer to a predetermined depth and forming a plurality of concave portions, each of which corresponds to the bottom of each channel of the first alumina layer, on the aluminum layer; performing second anodizing to form a second alumina layer having an array of a plurality of channels corresponding to the plurality of concave portions on the aluminum layer; forming a mask layer that covers a processing object layer on a substrate where the processing object layer has been formed; performing compression molding on the mask layer using the second alumina layer in the template and transferring the profile of the channel array in the second alumina layer to the mask layer; and etching the mask layer and the underlying processing object layer and transferring the compression molded profile of the mask layer to the processing object layer. 3. The method of claim 2, wherein the mask layer is made from photoresist or polymethylmethyacrylate (PMMA). 4. The method of claim 2, wherein the processing object layer is made from silicon. 5. The method of claim 3, wherein the processing object layer is made from silicon. 6. The method of claim 1, wherein the second anodizing is performed under the same conditions as the first anodizing. 7. (canceled) | This application claims the priority of Korean Patent Application No. 2003-25082, filed Apr. 21, 2003, the contents of which are incorporated herein by reference in their entirety. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an array of vertical nanochannels and a method of manufacturing a nanodot using the array, and more particularly, to a method of forming a self-ordered nanochannel-array by two-step anodizing and a method of fabricating a nanodot using the nanochannel-array. 2. Description of the Related Art Recently, researches have been actively conducted to form nano-scale patterns or structures in memories, laser diodes (LDs), photo diodes (PDs), transistors, far-infrared detectors, solar cells, optical modulators, and the likes. For example, a nanodot associated with an electronic control changes the number of bound electrons in correspondence to its size. Since electronic devices using nanodots can be actuated with a smaller number of electrons compared to conventional electronic devices, a threshold current level is lowered to enable low voltage actuation. The devices using nanodots also have the advantage of offering a high throughput with low voltage. A conventional nanodot fabrication method utilizes a traditional deposition process including low pressure chemical vapor deposition (LPCVD) to form Si/Si3N4 nuclei or sprays nanoparticles onto a substrate. However, the conventional approach makes it difficult to control the sizes of nanoparticles. Furthermore, spraying nanoparticles of an equal size cannot guarantee uniform nanodot distribution. Another conventional method is to use electron beam lithography or laser beam lithography. This approach not only makes it difficult to obtain a nanodot of the desired size due to process limitation but also suffers from restriction in reducing its size. Furthermore, it is well known that lithography is a complicated and expensive process. Meanwhile, Stephen Y. Chou et al. have proposed a method of forming a metal nanodot on a silicon substrate. This method involves imprinting a PMMA layer formed on a silicon substrate with a mold, forming a channel array to a predetermined depth, removing the residual PMMA from the bottom of a channel and forming a metal layer on the resulting structure, and soaking the substrate in an etching solution and lifting off the PMMA layer and residual metal thereon (Appl. Phys. Lett., Vol. 67. No. 21. 20 November 1995). According to this technique, the size or spacing of a nanodot is determined by the mold. That is, the nanodot size is limited by a microscale patterning of the mold such as photolithography. Thus, its size cannot be reduced to less than the limit allowed in a photolithography process. Hideki Masuda et al. have proposed a method of manufacturing a nanochannel-array that can be usefully used for developing various nanoscale devices (Appl. Phys. Lett. 71(19), 10 Nov. 1997). This method involves performing compression molding on a shallow concavity, carrying out an anodizing process, and forming a self-ordered channel-array. However, this method has a problem in that the size of each channel or array is limited by the mold. SUMMARY OF THE INVENTION The present invention provides a method for easily forming a smaller and highly ordered nanochannel-array using a self-alignment technique. The present invention also provides a method of manufacturing a nanodot using the highly ordered nanochannel-array, which is designed to allow a simplified and faster process and low manufacturing cost. According to an aspect of the present invention, there is provided a method of manufacturing a self-ordered nanochannel array which includes the steps of: performing first anodizing to form a first alumina layer having a channel array formed by a plurality of cavities on an aluminum substrate; etching the first alumina layer to a predetermined depth and forming a plurality of concave portions on the aluminum substrate, wherein each concave portion corresponds to the bottom of each channel of the first alumina layer; and performing second anodizing to form a second alumina layer having an array of a plurality of channels corresponding to the plurality of concave portions on the aluminum substrate. According to another aspect of the present invention, there is provided a method of manufacturing a nanodot, including the steps of: performing a first anodizing to form a first alumina layer having an array of a plurality of channels on a template containing an aluminum layer; etching the first alumina layer to a predetermined depth and forming a plurality of concave portions, each of which corresponds to the bottom of each channel of the first alumina layer, on the aluminum layer; performing second anodizing to form a second alumina layer having an array of a plurality of channels corresponding to the plurality of concave portions on the aluminum layer; forming a mask layer that covers a processing object layer on a substrate where the processing object layer has been formed; performing compression molding on the mask layer using the second alumina layer in the template and transferring the profile of the channel array in the second alumina layer to the mask layer; and etching the mask layer and the underlying processing object layer and transferring the compression molded profile of the mask layer to the processing object layer. In the nanodot manufacturing method, the mask layer may be made from photoresist or polymethylmethyacrylate (PMMA). The processing object layer may be made from silicon. BRIEF DESCRIPTION OF THE DRAWINGS The above objects and advantages of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings in which: FIGS. 1A-1E show steps of a method of manufacturing a self-ordered nanochannel-array using two-step anodizing according to the present invention; FIG. 2 shows a cross-section (left) and a top view (right) showing a nano-hole array of a nanochannel-array manufactured according to an embodiment of this invention; and FIGS. 3A-3H show steps of a method of manufacturing a nanodot using the nanochannel-array of FIG. 2 as a template according to an embodiment of this invention. DETAILED DESCRIPTION OF THE INVENTION Hereinafter, a method of manufacturing a self-ordered nanochannel-array and a method of manufacturing a nanodot using the nanochannel-array as a template according to preferred embodiments of this invention will be described with reference to the accompanying drawings. First, a method of manufacturing a nanochannel-array on an aluminum substrate will be described. The nanochannel-array manufacturing method according to this invention includes a two-step anodizing process. As shown in FIG. 1A, an aluminum substrate 11 is prepared. Here, the aluminum substrate 11 may be constructed from a pure aluminum plate or a structure in which an aluminum layer has been formed on a separate supporting substrate. Referring to FIG. 1B, the aluminum substrate 11 is oxidized to a predetermined depth by first anodizing to form a porous alumina layer 13. During the extending of the alumina layer 13 from the surface of the original aluminum surface 11 by the first anodizing, the first anodizing, the vertical shape of a channel 13a is irregularly distorted due to nonuniformity in morphology of the aluminum substrate 11 that begins to be oxidized. In FIG. 1C, the alumina layer 13 is cleaned off with an etching solution. In this case, equally nano-sized concave portions 11a remain to form an array on the aluminum substrate 11 that has been exposed after etching. Referring to FIG. 1D, second anodizing is performed under the same condition as was given for the first anodizing to form a porous alumina layer 14 having a plurality of channels 14a to a predetermined depth. As shown in FIG. 1E, the channel 14a is widened by appropriately adjusting the temperature and concentration of a solution and a value of an applied voltage only when necessary. FIG. 2 shows a cross-section (left) of the nanochannel-array formed by the two-step anodizing process, a top view (right) of the nanochannel-array presenting an arrangement of the nanochannels. The nanochannel-array described above can be used as a template in a method of forming a nanodot according to this invention. Referring to FIG. 3A, a substrate 5 on which a processing object layer 4 on which crystalline or amorphous silicon have been formed is prepared. Here, the substrate 5 may be a silicon substrate, and silicon oxide 5a is sandwiched between the processing object layer 4 and silicon substrate 5. Since the silicon oxide is only an example of material that can reside beneath the processing object layer 4, a material other than silicon oxide may be used. Furthermore, the processing object layer 4 may be constructed of a material other than silicon. That is, a nanodot manufacturing method according to this invention is not limited by the material forming the processing object layer 4, and a method of adopting this material provides another embodiment of this invention. Referring to FIG. 3B, a mask layer 6 made of photoresist or polymethylmethyacrylate (PMMA) is formed on the processing object layer 4 to a predetermined thickness. Here, the thickness of the mask layer 6 is set considering compressing molding. As shown in FIG. 3C, compression molding is performed on the mask layer 6 using a template 10 where the alumina layer 14 having an array of a plurality of channels has been formed on the aluminum substrate 11. At that time, the alumina layer 14 faces the mask layer 6 so that the profile of the channel array in the alumina layer 14 can be transferred to the mask layer 6. In FIG. 3D, the template 10 is separated from the mask layer 6, and as shown in FIG. 3G, etching is performed on the entire surface of the mask layer 6. In this case, RIE or ion milling is performed to etch the mask layer 6 by a uniform thickness. Sufficient etching proceeds under these conditions so that the template profile transferred to the mask layer 6 can be transferred to the processing object layer 4. After the transfer process, the processing object layer 4 remains in the form of nanodots. If residue 6′ of the mask layer 6 remains as shown in FIG. 3E after having processed the processing object layer 4 in the form of nanodots, the residue 6′ is removed as shown in FIG. 3F. This step can be skipped to the next one if no residue remains. As shown in FIG. 3H, if the processing object layer 4 is made of amorphous silicon, the processing object layer 4 is annealed by applying heat. The annealing process is carried out as needed and in particular when making amorphous silicon into crystalline silicon. The above steps for forming nanodots with the processing object layer 4 have been generally described herein. That is, the steps are only a part of the process of manufacturing an electric device so this invention is not limited by a method of fabricating a specific electric device. The nanochannel-array fabricating method according to this invention involves forming self-ordered concave portions by first anodizing and etching and then self-ordered channels by second anodizing. This invention allows a channel-array obtained in this way to be used as a template in place of a mold formed by lithography, thus eliminating the need to perform an expensive lithography process while providing a faster process that can be applied to a large area. Furthermore, this invention makes it possible to easily adjust channel spacing and size of a nanochannel-array through an anodizing process and then the size and spacing of a nanodot array fabricated using the nanochannel-array. The channel-array manufacturing method and a method of fabricating nanodots using the channel-array according to this invention can be applied to the manufacturing of various types of electronic devices including memories, laser diodes (LDs), photo diodes (PDs), transistors, far-infrared detectors, solar cells, and optical modulators. While this invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a method of manufacturing an array of vertical nanochannels and a method of manufacturing a nanodot using the array, and more particularly, to a method of forming a self-ordered nanochannel-array by two-step anodizing and a method of fabricating a nanodot using the nanochannel-array. 2. Description of the Related Art Recently, researches have been actively conducted to form nano-scale patterns or structures in memories, laser diodes (LDs), photo diodes (PDs), transistors, far-infrared detectors, solar cells, optical modulators, and the likes. For example, a nanodot associated with an electronic control changes the number of bound electrons in correspondence to its size. Since electronic devices using nanodots can be actuated with a smaller number of electrons compared to conventional electronic devices, a threshold current level is lowered to enable low voltage actuation. The devices using nanodots also have the advantage of offering a high throughput with low voltage. A conventional nanodot fabrication method utilizes a traditional deposition process including low pressure chemical vapor deposition (LPCVD) to form Si/Si 3 N 4 nuclei or sprays nanoparticles onto a substrate. However, the conventional approach makes it difficult to control the sizes of nanoparticles. Furthermore, spraying nanoparticles of an equal size cannot guarantee uniform nanodot distribution. Another conventional method is to use electron beam lithography or laser beam lithography. This approach not only makes it difficult to obtain a nanodot of the desired size due to process limitation but also suffers from restriction in reducing its size. Furthermore, it is well known that lithography is a complicated and expensive process. Meanwhile, Stephen Y. Chou et al. have proposed a method of forming a metal nanodot on a silicon substrate. This method involves imprinting a PMMA layer formed on a silicon substrate with a mold, forming a channel array to a predetermined depth, removing the residual PMMA from the bottom of a channel and forming a metal layer on the resulting structure, and soaking the substrate in an etching solution and lifting off the PMMA layer and residual metal thereon (Appl. Phys. Lett., Vol. 67. No. 21. 20 November 1995). According to this technique, the size or spacing of a nanodot is determined by the mold. That is, the nanodot size is limited by a microscale patterning of the mold such as photolithography. Thus, its size cannot be reduced to less than the limit allowed in a photolithography process. Hideki Masuda et al. have proposed a method of manufacturing a nanochannel-array that can be usefully used for developing various nanoscale devices (Appl. Phys. Lett. 71(19), 10 Nov. 1997). This method involves performing compression molding on a shallow concavity, carrying out an anodizing process, and forming a self-ordered channel-array. However, this method has a problem in that the size of each channel or array is limited by the mold. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides a method for easily forming a smaller and highly ordered nanochannel-array using a self-alignment technique. The present invention also provides a method of manufacturing a nanodot using the highly ordered nanochannel-array, which is designed to allow a simplified and faster process and low manufacturing cost. According to an aspect of the present invention, there is provided a method of manufacturing a self-ordered nanochannel array which includes the steps of: performing first anodizing to form a first alumina layer having a channel array formed by a plurality of cavities on an aluminum substrate; etching the first alumina layer to a predetermined depth and forming a plurality of concave portions on the aluminum substrate, wherein each concave portion corresponds to the bottom of each channel of the first alumina layer; and performing second anodizing to form a second alumina layer having an array of a plurality of channels corresponding to the plurality of concave portions on the aluminum substrate. According to another aspect of the present invention, there is provided a method of manufacturing a nanodot, including the steps of: performing a first anodizing to form a first alumina layer having an array of a plurality of channels on a template containing an aluminum layer; etching the first alumina layer to a predetermined depth and forming a plurality of concave portions, each of which corresponds to the bottom of each channel of the first alumina layer, on the aluminum layer; performing second anodizing to form a second alumina layer having an array of a plurality of channels corresponding to the plurality of concave portions on the aluminum layer; forming a mask layer that covers a processing object layer on a substrate where the processing object layer has been formed; performing compression molding on the mask layer using the second alumina layer in the template and transferring the profile of the channel array in the second alumina layer to the mask layer; and etching the mask layer and the underlying processing object layer and transferring the compression molded profile of the mask layer to the processing object layer. In the nanodot manufacturing method, the mask layer may be made from photoresist or polymethylmethyacrylate (PMMA). The processing object layer may be made from silicon. | 20040407 | 20071016 | 20070906 | 95738.0 | H01L21302 | 0 | CHEN, KIN CHAN | METHOD OF MANUFACTURING SELF-ORDERED NANOCHANNEL-ARRAY AND METHOD OF MANUFACTURING NANODOT USING THE NANOCHANNEL-ARRAY | UNDISCOUNTED | 0 | ACCEPTED | H01L | 2,004 |
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10,819,198 | ACCEPTED | Solar cell module having an electric device | A solar cell module includes a front member placed at a light-incident side of the module; a sealing member having an exposed section that is not covered with the front member; solar cell elements that are sealed with the sealing member and covered with the front member; and an electric device, stored in a housing, for extracting electricity generated by the solar cell elements. The housing is fixed on the exposed section and is located at a light-incident side of the module. | 1. A solar cell module comprising: a front member provided at a light-incident side of the solar cell module; a sealing member having an exposed section that is not covered with the front member; solar cell elements that are sealed with the sealing member and covered with the front member; and an electric device, stored in a housing, for extracting electricity generated by the solar cell elements, wherein the housing is fixed on the exposed section and is located at the light-incident side of the solar cell module. 2. The solar cell module according to claim 1, wherein the housing is directly fixed on the exposed section. 3. The solar cell module according to claim 2, wherein the exposed section has an adhesive function. 4. The solar cell module according to claim 1, wherein the housing is fixed on the exposed section with an adhesive, with the adhesive being sandwiched between the housing and the exposed section. 5. The solar cell module according to claim 1, wherein the exposed section extends out past an outer edge of the front member. 6. The solar cell module according to claim 1, wherein the exposed section is used for extracting electricity from the solar cell elements. 7. The solar cell module according to claim 1, further comprising a lead electrode through which the electricity generated by the solar cell elements is extracted, the lead electrode being electrically connected to the solar cell elements and the electric device. 8. The solar cell module according to claim 7, wherein the lead electrode is placed on the exposed section. 9. The solar cell module according to claim 8, wherein the lead electrode comprises a metal sheet. 10. The solar cell module according to claim 1, further comprising a moisture-proof layer disposed between the electric device and the sealing member. 11. The solar cell module according to claim 1, wherein the moisture-proof layer comprises a metal strip. 12. The solar cell module according to claim 1, further comprising an electrical wiring member that is connected to the electric device and fixed on the exposed section. 13. The solar cell module according to claim 1, wherein the housing is filled with a resin. 14. The solar cell module according to claim 1, wherein the electric device is a terminal box. 15. The solar cell module according to claim 1, wherein the electric device is a converter for converting electricity generated by the solar cell elements. 16. The solar cell module according to claim 1, further comprising a rear member located at a non-light-incident side of the solar cell module, wherein a portion of the sealing member is disposed between the rear member and the solar cell elements. 17. The solar cell module according to claim 16, wherein the exposed section extends out past an outer edge of the front member. 18. The solar cell module according to claim 17, wherein the rear member extends out past an outer edge of the front member. 19. A method of manufacturing the solar cell module according to claim 1, comprising the steps of: connecting the solar cell elements in series; stacking a rear member, a first sheet, the solar cell elements, a second sheet, and the front member in that order to form a layered structure; and heating and pressing the layered structure, whereby the solar cell elements are sealed, wherein the first sheet and the rear member each have a portion which extends out past an outer edge of the front member, and wherein the sealing member is formed from the first and second sheets. 20. The method according to claim 19, wherein the housing is placed on the portion of the first sheet which extends out past an outer edge of the front member before the heating and pressing step; and wherein the housing is directly fixed to the exposed section during the heating and pressing step. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to solar cell modules including solar cell elements sealed with a sealing member and particularly relates to a solar cell module including an electric device for extracting electricity generated by solar cell elements. 2. Description of the Related Art In general, solar cell assemblies include a plurality of solar cell elements, connected to each other, for generating electricity with a desired voltage and current. Such assemblies cannot be used under harsh outdoor conditions without sealing the solar cell elements. Therefore, the solar cell elements must be sealed with sealing members, whereby the assemblies are transformed into solar cell modules. The sealing members usually contain ethylene-vinyl acetate (EVA) copolymer. Front members, such as glass sheets or fluorine resin films, having high weather resistance and transparency are placed at the tops of light-receiving faces of the solar cell modules. On the other hand, rear members, such as fluorine resin films or polyester films, having high weather resistance and insulation performance are placed on the faces opposite to the light-receiving faces. In the solar cell modules, the solar cell elements sealed with the sealing member are placed between the front members and rear members. In order to extract electricity from the solar cell modules, electrodes connected to the solar cell elements are usually routed out of the sealing members, the front members, or the rear members. Techniques for routing the electrodes are disclosed in some documents. In the technique disclosed in Japanese Patent Laid-Open No. 2000-243996, an opening is formed such that the opening extends through a sealing member and a rear member to electrodes, placed on the side close to a rear face of a solar cell module, for extracting electricity, and lead wires placed in the opening are each soldered to the corresponding electrodes. In the technique disclosed in Japanese Patent Laid-Open No. 7-263768 or 10-335682, a notch is formed in end sections of a front or rear member and a sealing member such that electrodes are exposed. Electrodes routed outside must be electrically insulated securely. That is, rainwater, which causes an electrical breakdown in connections of the electrodes, must be prevented from penetrating the connections if a solar cell module is used under harsh outdoor conditions. Therefore, usually, the electrode connections are fully covered with a terminal box or a junction box referred to as a housing. The electrodes are connected to cable connectors, extending out of the terminal box, with terminal blocks or the like placed in the terminal box, whereby the electricity can be withdrawn. In order to prevent the corrosion of the electrodes and connections placed in the terminal box, and in order to maintain the water tightness of the exposed portions of the electrodes, the terminal box is usually filled with a silicone sealant or the like. FIGS. 9 and 10 each illustrate a solar cell module with the terminal box. Reference numeral 23 represents a terminal box, reference numeral 24 represents a silicone sealant, and reference numeral 25 represents a connector cable. In view of workability, it can be preferable to avoid placing protrusions, for example, the terminal box and the like, on rear faces of solar cell modules. In recent years, for example, a building-integrated photovoltaic module functioning as a building material has been extensively developed because such a module is effective in reducing cost for manufacturing photovoltaic systems and has a good appearance when placed on buildings. In the module, in view of workability, it can be preferable to avoid placing a terminal box on the rear face of the module. In this case, electrodes must be routed out of a front member and a terminal box must be placed on the front member, which cannot be securely joined to the terminal box. Since the front member must have high weather resistance, the front member usually includes a glass sheet or a fluorine resin film. In particular, when the front member includes such a fluorine resin film, the terminal box cannot be securely joined to the fluorine resin film. Therefore, the terminal box may be peeled off from the fluorine resin film. In order to reduce cost for manufacturing solar cell modules, attempts have been made to reduce the thickness of the modules. Therefore, sections for extracting electricity must be simplified. Since new solar cell modules, which are readily installed and have good appearance in common with the building-integrated solar cell module, are being developed, the following components are in demand: electrode-routing components and electric device-fixing components which do not impair the flatness of the rear faces when electric devices, for example, terminal boxes, are placed on the modules and which are helpful in simplifying manufacturing steps, improving the yield, and greatly reducing manufacturing cost thereby. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a solar cell module which can be manufactured at low cost, from which electricity generated by solar cell elements can be efficiently extracted, and to which an electric device connected to the elements can be securely fixed. In order to solve the above problems individually or in combination, the inventors have conducted extensive research and then found that configuration described below is advantageous. A solar cell module of the present invention includes a front member placed at a light-incident side of the solar cell module; a sealing member having an exposed section that is not covered with the front member; solar cell elements that are sealed with the sealing member and covered with the front member; and an electric device, stored in a housing, for extracting electricity generated by the solar cell elements. The housing is fixed on the exposed section and is located at the light-incident side of the solar cell module. According to the above configuration, since the electric device is securely fixed to the exposed section, the electric device can be prevented from being detached from the exposed section and the electrical insulation of the lead electrodes and electric device can be prevented from being deteriorated if the solar cell module is exposed outdoors over a long period. Therefore, the solar cell module has high reliability. In the solar cell module, the exposed section preferably extends out past an outer edge of the front member. In order to expose a portion of the sealing member from the front member, a slit opening may be formed in the front member before the solar cell elements are sealed. In such a method, the lead electrodes for extracting the electricity generated by the solar cell elements must be aligned with the slit opening when the solar cell elements, the sealing member, and the front member are stacked. Therefore, the method is complicated and is not fit for automation. However, in the present invention, the exposed section preferably extends out past an outer edge of the front member and the alignment is not therefore necessary; hence, a method for manufacturing the solar cell module is simple and the solar cell module can be manufactured at low cost. When the front member is made of glass, the formation of the opening in the front member causes an increase in manufacturing cost. However, in the present invention, the exposed section preferably extends out of the front member and the opening need not be therefore formed in the glass front member; hence, manufacturing cost is not high. Electrical wiring members connected to the electric device may be fixed on the exposed section, whereby an external force exerted on the electrical wiring members is not directly transmitted to the electric device. Therefore, the electric device can be securely fixed to the exposed section and the reliability of the electric device is high. A moisture-proof layer may be placed between the electric device and the sealing member, whereby moisture passing through the sealing member can be prevented from penetrating the electric device; hence, moisture can be prevented from lowering the adhesion of the housing, which stores the electric device, to the sealing member. Furthermore, moisture can be prevented from corroding wiring members placed in the electric device. If the moisture-proof layer includes a metal sheet, heat generated by the electric device can be released through the metal sheet. According to the above configuration, an electrode-routing section and electric device-fixing section of the solar cell module have high reliability and can be formed at low cost. Furthermore, the solar cell module can be manufactured at low cost by a simple method. The electric device can be securely fixed to the exposed section, whereby the reliability of the electric device is ensured. Therefore, the electric device can be prevented from being detached from the exposed section and the insulation of the lead electrodes and the electric device can be prevented from being deteriorated if the solar cell module is exposed over a long period. Further objects, features, and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a schematic plan view showing a solar cell module according to a first embodiment of the present invention, and FIG. 1B is a schematic sectional view of the solar cell module taken along the line 1B-1B′. FIG. 2 is a schematic sectional view showing a solar cell module according to a second embodiment of the present invention. FIG. 3 is a schematic plan view showing a solar cell module according to a third embodiment of the present invention. FIG. 4 is a schematic sectional view showing a solar cell module according to a fourth embodiment of the present invention. FIG. 5 is a schematic sectional view showing a solar cell module according to a fifth embodiment of the present invention. FIG. 6A is a schematic plan view showing a housing that is placed in the solar cell module of the fourth embodiment and is not yet filled with filler, FIG. 6B is a schematic plan view showing the housing filled with the filler, and FIG. 6C is a schematic sectional view of the housing filled with the filler taken along the line 6C-6C′. FIG. 7A is a schematic plan view showing a solar cell module of Example 1 which has been processed in a sealing step, and FIG. 7B is a schematic sectional view of the solar cell module taken along the line 7B-7B′. FIG. 8 is a sectional view showing the solar cell module of Example 1 which is not yet processed in the sealing step. FIG. 9 is a schematic sectional view showing an example of a solar cell module including terminal boxes. FIG. 10 is a schematic sectional view showing an example of another solar cell module including terminal boxes. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a schematic plan view showing a solar cell module having a section on which electrodes and an electric device are placed according to an embodiment of the present invention. FIG. 1B is a schematic sectional view showing the solar cell module. With reference to FIGS. 1A and 1B, reference numeral 1 represents a solar cell element, reference numeral 2 represents a front member, reference numeral 3 represents a sealing member, reference numeral 4 represents a rear member, reference numeral 5 represents a lead electrode, reference numeral 6 represents a housing, reference numeral 7 represents an electrical wiring member, reference numeral 8 represents a terminal block, and reference numeral 9 represents an adhesive. The solar cell module of the present invention includes the front member 2 placed at a light-incident side of the module; the solar cell elements 1 that are sealed with the sealing member 3 and covered with the front member 2; and an electric device for extracting electricity generated by the solar cell elements 1. The sealing member 3 has an exposed section that is not covered with the front member 2. The housing 6 storing the electric device is joined to the exposed section of the sealing member 3 and is located at a light-incident side of the module. In the solar cell module, the exposed section is preferably a region of the sealing member 3 extending out past an outer edge of the front member 2. For example, the following configuration is preferable: the sealing member 3 and the rear member 4 each have corresponding protrusions extending out past an outer edge of the front member 2, electricity generated by the solar cell elements is sent through metal strips connected to the solar cell elements 1 to apparatuses placed outside the sealing member 3, the metal strips are placed on the exposed section, and the electric device for receiving the electricity sent through the metal strips is connected to the metal strips and fixed on the exposed section. As shown in FIGS. 1A and 1B, in order to extract the electricity generated by the solar cell elements 1, one lead electrode 5 is connected to an electrode placed on the rear face of a solar cell element 1. Another lead electrode 5 (not shown) is connected to a bus bar electrode (not shown) placed on the solar cell elements 1. The solar cell elements 1 may be connected to each other in series or in parallel according to needs such as voltage and current. The lead electrodes 5 are routed out of the sealing member 3 having the exposed section extending out of the front member 2. In order to allow the sealing member 3 to be partly exposed, the sealing member 3 may have a protrusion extending out past an outer edge of the front member 2 as shown in FIGS. 1A and 1B or the front member 2 may have a notch or opening. The sealing member 3 preferably has the protrusion because the protrusion can be readily formed. In particular, when the front member 2 is made of an unmachinable material such as glass, the sealing member 3 having the protrusion can be prepared at a lower cost than that for forming such a notch or opening in the front member 2. Since the exposed section of the sealing member 3 extends out past an outer edge of the front member 2, the rear member 4 preferably has a section extending under the exposed section. If the rear member 4 does not have such an extending section, the exposed section is bent or broken at the base in some cases when the electric device described below is placed an the exposed section, because the sealing member 3 has an insufficient stiffness. If the extending section supports the exposed section, the above problem can be avoided. The housing 6 storing the electric device is fixed on the exposed section. Examples of the electric device include a terminal box, a converter such as a transformer or an inverter, and an electronic component such as a molded diode. The adhesive 9 is used to fix the housing 6 to the exposed section. The adhesive 9 may contain one selected from known resins such as a silicone resin, an epoxy resin, an acrylic resin, a urethane resin, and a polyolefin resin. The adhesive 9 may be of a reactive curing type or a hot melt type or may be a double faced adhesive tape. Among those materials, the silicone resin and the double faced adhesive tape containing the acrylic resin are preferable because they have a good balance between the weather resistance and adhesion. The lead electrodes 5 are connected to the terminal blocks 8 and/or lead wires placed in the housing 6, whereby the solar cell elements 1 are electrically connected to the electric device. The top of the housing 6 is covered with a lid member (not shown) according to needs, whereby the housing 6 is sealed up. In another embodiment, as shown in FIG. 2, the housing 6 is preferably fixed to the exposed section directly without using the adhesive 9. Since the sealing member 3 for sealing the solar cell elements 1 has an adhesive function and high weather resistance, the reliability of adhesion is satisfactory. When the electric device placed in the housing 6 has heat resistance, the housing 6 may be joined to the exposed section in a step of sealing the solar cell elements 1, whereby a process for manufacturing the module can be simplified. The electric device is usually connected to wires. In another embodiment, the sealing member 3 has a bare section 10 and each electrical wiring member 7 may be fixed to the bare section 10 as shown in FIG. 3. In such a configuration, when the electrical wiring member 7 is pulled, the pulling force is not directly transmitted to the electric device, whereby the electric device can be prevented from being detached from the bare section 10. The electrical wiring member 7 may be mechanically fixed to the bare section 10 with a fixture or fixed to the bare section 10 using an adhesive, a sealant, or the like. In another embodiment, a moisture-proof layer 30 may be placed between the electric device and the sealing member 3 as shown in FIG. 4, whereby failures due to moisture can be prevented from occurring in the electric device. The moisture-proof layer 30 preferably includes a metal strip 11 because heat, which causes trouble in the electric device, can be effectively released from the electric device. The metal strip 11 may be selected among strips having high corrosion resistance and heat conductivity, and an aluminum strip is the most preferable. The metal strip may be laminated with a resin film 12. For example, an aluminum strip laminated with a polyester film is preferable. In order to ensure the weather resistance, moisture resistance, and electrical insulation of electric components included in the electric device placed in the housing 6, the housing 6 may be filled with a resin filler 13 as shown in FIG. 5. Examples of the resin filler 13 include a silicone resin, an acrylic resin, an epoxy resin, a urethane resin, a polyolefin resin, and a polyester resin. In particular, the silicone resin is preferable in view of an environment in which the solar cell module is used, because the silicone resin has high weather resistance. In order to prevent moisture from penetrating the electric device and in order to enhance heat release properties, a metal plate or a metal sheet may be placed on the resin filler 13. In this case, the metal plate or sheet functions as a lid member 14. The components of the solar cell module will now be described in detail. The sealing member 3 covers irregularities due to the solar cell elements 1, protects the solar cell elements 1 from harsh conditions such as temperature variations, moisture, and impact, and ensures the adhesion of the solar cell elements 1 to the front member 2 or rear member 4. The sealing member 3 may contain ethylene-vinyl acetate (EVA) copolymer, ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate (EEA) copolymer, ethylene-methyl methacrylate (EMAA) copolymer, an ionomer resin, a polyvinyl butyral resin, or the like. Among those materials, the EVA copolymer is preferable, because the copolymer has a good balance among the properties of weather resistance, adhesion, filling properties, heat resistance, cold resistance, and shock resistance when used for solar cells. Since the EVA copolymer that has not yet been cross-linked has a low deformation temperature, deformation or creep occurs in the copolymer when used at a high temperature. Therefore, the EVA copolymer is preferably cross-linked, whereby the heat resistance is increased. The solar cell elements 1 may be selected among the following known elements according to different needs: (1) crystalline silicon solar cells, (2) polycrystalline silicon solar cells, (3) microcrystalline silicon solar cells, (4) amorphous silicon solar cells, (5) copper-indium selenide solar cells, and (6) compound semiconductor solar cells. A desired number of the solar cell elements 1 are electrically connected to each other depending on the voltage or current. Alternatively, the solar cell elements 1 may be arranged on an insulating substrate in an integrated manner, whereby a desired voltage or current is obtained. Since the front member 2 is located at the top of the solar cell module, the front member 2 must have superior properties, such as transparency, weather resistance, stain resistance, and mechanical strength, for ensuring the long-term reliability of the solar cell module exposed outdoors. Examples of the front member 2 include a sheet of tempered white glass, a fluorocarbon resin film, and an acrylic resin film. The tempered white glass is widely used for solar cell modules because the glass has high transparency and shock resistance and is therefore difficult to crack. In recent years, there has been a demand for modules that are light-weight and flexible. Therefore, a resin film is suitable for the front member 2. In particular, the fluorocarbon resin film is preferable due to the high weather resistance and stain resistance. Examples of the fluorocarbon resin film include a polyvinylidene fluoride resins a polyvinyl fluoride resin, and ethylene-tetrafluoroethylene copolymer The polyvinylidene fluoride resin has better weather resistance than that of the other resins; however, the ethylene-tetrafluoroethylene copolymer has a better balance between weather resistance, mechanical strength and higher transparency as compared with the other resins. The rear member 4 protects the solar cell elements 1, prevents moisture from penetrating the solar cell elements 1, and electrically Insulates the solar cell elements 1. A material for the rear member 4 is preferably superior in electrical insulation and long-term durability and able to endure thermal expansion and thermal shrinkage. Preferable examples of such a material include a polyvinyl fluoride film, a nylon film, a polyethylene terephthalate film, and a glass sheet. In order to mechanically reinforce the rear member 4, a support sheet may be placed under the rear member 4. Examples of the support sheet include a metal sheet, a fiber-reinforced plastic (FRP) sheet, and a ceramic sheet. In building-integrated photovoltaic modules, a building material functions as the support sheet. The lead electrodes 5 are electrically connected to the solar cell elements 1 and used for extracting electricity from the solar cell module. A material for the lead electrodes 5 can be selected from known materials such as a copper sheet, a tin-lead plated copper sheet, and a tin plated copper sheet. Examples of the present invention will now be described in detail. EXAMPLE 1 A procedure for manufacturing a solar cell module according to an embodiment of the present invention is described below with reference to FIGS. 5, 7A, 7B, and 8. The solar cell module includes a plurality of solar cell elements 1 (amorphous silicon solar cells) each including corresponding conductive substrates, rear reflecting layers, semiconductor photoactive layers, transparent electrode layers disposed in that order and further includes interdigital collector electrodes placed on the transparent electrode layers and a bus bar electrode connected to the comblike collector electrodes. The solar cell elements 1 are connected in series. One of the lead electrodes 5 each including a tin plated copper sheet is soldered to an electrode connected to an end of the series of solar cell elements 1. As shown in FIG. 8, the following components are stacked on a polyester film 84 having a thickness of 100 μm in this order: a first sheet 832 having a thickness of 0.4 mm, the resulting solar cell elements 1, a second sheet 831 having a thickness of 0.4 mm, and a transparent fluorocarbon resin film 82 having a thickness of 50 μm. The first and second sheets 832 and 831 contain an EVA resin for sealing the solar cell elements 1. The resulting components are heated and then pressed with a vacuum laminator, thereby sealing the solar cell elements 1. In the above configuration, the polyester film 84 and the first sheet 832 disposed thereon each have corresponding protrusions extending out past an outer edge of the fluorocarbon resin film 82. The resulting lead electrode 5 is placed on the protrusion of the first sheet 832, the protrusion not being covered by the fluorocarbon resin film 82. According to the above procedure, the solar cell module having an electrode-routing section shown in FIGS. 7A and 7B can be prepared. As shown in FIG. 5, a housing 6 functioning as a terminal box is joined to the protrusion of the first sheet 832 with a moisture-curable silicone adhesive 9. An end of the lead electrode 5 is raised and then soldered to a terminal block 8 placed in the housing 6. An electrical wiring member 7 routed into the housing 6 is soldered to the resulting terminal block 8. A resin filler 13 containing an addition reaction-type two-part silicone potting compound is placed in the housing 6 such that the housing 6 is filled with the resin filler 13. A lid member 14 including an aluminum plate is placed on the top of the resulting housing 6, thereby sealing the housing 6. Since there is no protrusion on the rear face of the solar cell module prepared according to the above procedure, the module can be readily joined to a stand or a building material by a simple method such as a joining method using an adhesive without depending on the shape of the stand or the building material. Since the electrode-routing section can be readily formed by placing the lead electrode 5 on the protrusion of the first sheet 832 in the stacking step, the module can be manufactured by an automation progress, whereby manufacturing cost can be reduced. In order to evaluate the reliability of the electrode-routing section and the housing-fixing section, the solar cell module was investigated. The module was subjected to a temperature/humidity cycle test. In the test, the module was placed in a chamber having a temperature of 85° C. and a relative humidity of 85% for 22 hours and then maintained at −40° C. for 30 minutes, and that cycle was repeated 50 times. The housing-fixing section of the resulting module was immersed in a solution having an electric conductivity of 350 mS/cm, a voltage of 2,200 V was applied across the solution and the lead electrode 5, and then the leak current was determined, whereby the hermeticity of the housing 6 was evaluated. The investigation result showed that the leakage current was not increased after the module was subjected to the test, that is, the module had sufficient electrical insulation. EXAMPLE 2 A solar cell module of this example has a superstrate structure in which a glass sheet is placed at the top of a light-incident side of the module. This module can be prepared according to the procedure below using a tempered white glass sheet having a thickness of 3.3 mm instead of the fluorocarbon resin film 82 used in Example 1. In a sealing step, the following components are stacked: the tempered white glass sheet, a first EVA resin sheet having a thickness of 0.6 mm, solar cell elements connected in series, a second EVA resin sheet having a thickness of 0.4 mm, and a polyester film having a thickness of 100 μn. The resulting components are heated and then pressed with a vacuum laminator, whereby the solar cell elements are sealed. In the module, the second EVA resin sheet and the polyester film placed under the solar cell elements each have corresponding protrusions extending out of the tempered white glass sheet, and one of the lead electrodes is placed under the protrusion of the polyester film. This configuration is different from that of the solar cell module of Example 1. Other portions of the solar cell module of this example are substantially the same as those of the solar cell module of Example 1. The solar cell module prepared according to the above procedure was investigated in the same manner as that of Example 1. The investigation result showed that the module had satisfactory hermeticity and sufficient electrical insulation. EXAMPLE 3 A solar cell module of this example can be prepared according to the procedure described below. Solar cell elements, EVA resin sheets, a fluorocarbon resin sheet, and a polyester film are stacked. One of the EVA resin sheets has a protrusion, and a housing functioning as a terminal box is placed on the protrusion. The above components are heated and then pressed with a vacuum laminator, whereby the housing is directly joined to the protrusion. That is, the housing is joined to the protrusion in the step of sealing the solar cell elements That is different from the sealing step of Example 1. The solar cell module prepared according to the above procedure was investigated in the same manner as that of Example 1. The investigation result showed that the module had no defects. Since an adhesive is not used in a step of joining the housing to the protrusion, a process for manufacturing the module can be simplified. EXAMPLE 4 Steps prior to a step of preparing solar cell elements 1 are the same as those of Example 1. Steps subsequent to the preparing step are described below with reference to FIGS. 6A to 6C. One of lead electrodes 5 each including corresponding tin-plated copper sheets is soldered to a bus bar electrode 17 and the other one is soldered to a conductive substrate. The bus bar electrode 17 functions as a first electrode for the solar cell elements 1 and is placed at a light-incident side of the solar cell module, and the conductive substrate functions as a second electrode for the solar cell elements 1. The following components are stacked on a polyester film having a thickness of 200 μm in this order: a first sheet having a thickness of 0.4 mm, the solar cell elements 1, a second sheet having a thickness of 0.4 mm, and a transparent fluorocarbon resin film having a thickness of 50 μm. The first and second sheets contain an EVA resin for sealing the solar cell elements 1. The resulting components are heated and then pressed with a vacuum laminator, thereby sealing the solar cell elements 1. In the above configuration, the polyester film and the first sheet disposed thereon each have corresponding protrusions extending out past an outer edge of the fluorocarbon resin film. A moisture-proof layer 20 including an aluminum sheet 19 laminated with a polyester film 18 is placed on the protrusion of the first sheet. Ends of the lead electrodes 5 are placed on the moisture-proof layer 20. The lead electrodes 5 are each soldered to corresponding input leads 16 connected to an electronic circuit board 15 included in a DC transformer. A housing 6 is joined to the protrusion of the first sheet with a moisture-curable silicone adhesive 9. Electrical wiring members 7 routed into the housing 6 are each soldered to corresponding terminal blocks placed on the electronic circuit board 15. An addition reaction-type two-part silicone potting compound 13 is placed in the housing 6 such that the housing 6 is filled with the addition reaction-type two-part silicone potting compound 13. A lid member 14 including an aluminum plate is placed on the top of the resulting housing 6, thereby sealing the housing 6. In order to evaluate the reliability of the electrode-routing section and the transformer-joining section, the solar cell module prepared according to the above procedure was subjected to a temperature/humidity cycle test in the same manner as that of Example 1 while a predetermined voltage was applied to the transformer. After the test was finished, the hermeticity of the transformer-joining section was evaluated. The evaluation result showed that the electronic circuit board 15 of the transformer was electrically insulated and the transformer-joining section of the module of this example had satisfactory hermeticity. Moisture was prevented from penetrating the electronic circuit board 15 by the aluminum sheet 19 disposed below the transformer and lid member 14, whereby wires and electronic components disposed on the electronic circuit board 15 were prevented from being corroded and failures were therefore prevented from occurring in the transformer. Furthermore, pseudo-sunlight having a brightness of 1 sun was applied to the transformer-joining section at an atmospheric temperature of 40° C. using a solar simulator. The transformer was prevented from being over-heated because of the heatsink effect of the aluminum sheet 19 and lid member 14. Therefore, the transformer was operated without trouble. As described above, a solar cell module of the present invention includes an electric device placed at a light-incident side of the solar cell module and also Includes an electrode-routing section and an electric device-fixing section, which can be formed at low cost even if a front member is made of resin or glass. Such sections can be used not only for housings but also for devices, such as transformers, including electronic substrate boards, whereby such devices can be operated outdoors over a long period with no trouble. In the above examples, the solar cell elements made of amorphous silicon are used. However, other solar cell elements made of crystalline silicon, polycrystalline silicon, or microcrystalline silicon may be used. While the present invention has been described with reference to what are presently considered to be the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to solar cell modules including solar cell elements sealed with a sealing member and particularly relates to a solar cell module including an electric device for extracting electricity generated by solar cell elements. 2. Description of the Related Art In general, solar cell assemblies include a plurality of solar cell elements, connected to each other, for generating electricity with a desired voltage and current. Such assemblies cannot be used under harsh outdoor conditions without sealing the solar cell elements. Therefore, the solar cell elements must be sealed with sealing members, whereby the assemblies are transformed into solar cell modules. The sealing members usually contain ethylene-vinyl acetate (EVA) copolymer. Front members, such as glass sheets or fluorine resin films, having high weather resistance and transparency are placed at the tops of light-receiving faces of the solar cell modules. On the other hand, rear members, such as fluorine resin films or polyester films, having high weather resistance and insulation performance are placed on the faces opposite to the light-receiving faces. In the solar cell modules, the solar cell elements sealed with the sealing member are placed between the front members and rear members. In order to extract electricity from the solar cell modules, electrodes connected to the solar cell elements are usually routed out of the sealing members, the front members, or the rear members. Techniques for routing the electrodes are disclosed in some documents. In the technique disclosed in Japanese Patent Laid-Open No. 2000-243996, an opening is formed such that the opening extends through a sealing member and a rear member to electrodes, placed on the side close to a rear face of a solar cell module, for extracting electricity, and lead wires placed in the opening are each soldered to the corresponding electrodes. In the technique disclosed in Japanese Patent Laid-Open No. 7-263768 or 10-335682, a notch is formed in end sections of a front or rear member and a sealing member such that electrodes are exposed. Electrodes routed outside must be electrically insulated securely. That is, rainwater, which causes an electrical breakdown in connections of the electrodes, must be prevented from penetrating the connections if a solar cell module is used under harsh outdoor conditions. Therefore, usually, the electrode connections are fully covered with a terminal box or a junction box referred to as a housing. The electrodes are connected to cable connectors, extending out of the terminal box, with terminal blocks or the like placed in the terminal box, whereby the electricity can be withdrawn. In order to prevent the corrosion of the electrodes and connections placed in the terminal box, and in order to maintain the water tightness of the exposed portions of the electrodes, the terminal box is usually filled with a silicone sealant or the like. FIGS. 9 and 10 each illustrate a solar cell module with the terminal box. Reference numeral 23 represents a terminal box, reference numeral 24 represents a silicone sealant, and reference numeral 25 represents a connector cable. In view of workability, it can be preferable to avoid placing protrusions, for example, the terminal box and the like, on rear faces of solar cell modules. In recent years, for example, a building-integrated photovoltaic module functioning as a building material has been extensively developed because such a module is effective in reducing cost for manufacturing photovoltaic systems and has a good appearance when placed on buildings. In the module, in view of workability, it can be preferable to avoid placing a terminal box on the rear face of the module. In this case, electrodes must be routed out of a front member and a terminal box must be placed on the front member, which cannot be securely joined to the terminal box. Since the front member must have high weather resistance, the front member usually includes a glass sheet or a fluorine resin film. In particular, when the front member includes such a fluorine resin film, the terminal box cannot be securely joined to the fluorine resin film. Therefore, the terminal box may be peeled off from the fluorine resin film. In order to reduce cost for manufacturing solar cell modules, attempts have been made to reduce the thickness of the modules. Therefore, sections for extracting electricity must be simplified. Since new solar cell modules, which are readily installed and have good appearance in common with the building-integrated solar cell module, are being developed, the following components are in demand: electrode-routing components and electric device-fixing components which do not impair the flatness of the rear faces when electric devices, for example, terminal boxes, are placed on the modules and which are helpful in simplifying manufacturing steps, improving the yield, and greatly reducing manufacturing cost thereby. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a solar cell module which can be manufactured at low cost, from which electricity generated by solar cell elements can be efficiently extracted, and to which an electric device connected to the elements can be securely fixed. In order to solve the above problems individually or in combination, the inventors have conducted extensive research and then found that configuration described below is advantageous. A solar cell module of the present invention includes a front member placed at a light-incident side of the solar cell module; a sealing member having an exposed section that is not covered with the front member; solar cell elements that are sealed with the sealing member and covered with the front member; and an electric device, stored in a housing, for extracting electricity generated by the solar cell elements. The housing is fixed on the exposed section and is located at the light-incident side of the solar cell module. According to the above configuration, since the electric device is securely fixed to the exposed section, the electric device can be prevented from being detached from the exposed section and the electrical insulation of the lead electrodes and electric device can be prevented from being deteriorated if the solar cell module is exposed outdoors over a long period. Therefore, the solar cell module has high reliability. In the solar cell module, the exposed section preferably extends out past an outer edge of the front member. In order to expose a portion of the sealing member from the front member, a slit opening may be formed in the front member before the solar cell elements are sealed. In such a method, the lead electrodes for extracting the electricity generated by the solar cell elements must be aligned with the slit opening when the solar cell elements, the sealing member, and the front member are stacked. Therefore, the method is complicated and is not fit for automation. However, in the present invention, the exposed section preferably extends out past an outer edge of the front member and the alignment is not therefore necessary; hence, a method for manufacturing the solar cell module is simple and the solar cell module can be manufactured at low cost. When the front member is made of glass, the formation of the opening in the front member causes an increase in manufacturing cost. However, in the present invention, the exposed section preferably extends out of the front member and the opening need not be therefore formed in the glass front member; hence, manufacturing cost is not high. Electrical wiring members connected to the electric device may be fixed on the exposed section, whereby an external force exerted on the electrical wiring members is not directly transmitted to the electric device. Therefore, the electric device can be securely fixed to the exposed section and the reliability of the electric device is high. A moisture-proof layer may be placed between the electric device and the sealing member, whereby moisture passing through the sealing member can be prevented from penetrating the electric device; hence, moisture can be prevented from lowering the adhesion of the housing, which stores the electric device, to the sealing member. Furthermore, moisture can be prevented from corroding wiring members placed in the electric device. If the moisture-proof layer includes a metal sheet, heat generated by the electric device can be released through the metal sheet. According to the above configuration, an electrode-routing section and electric device-fixing section of the solar cell module have high reliability and can be formed at low cost. Furthermore, the solar cell module can be manufactured at low cost by a simple method. The electric device can be securely fixed to the exposed section, whereby the reliability of the electric device is ensured. Therefore, the electric device can be prevented from being detached from the exposed section and the insulation of the lead electrodes and the electric device can be prevented from being deteriorated if the solar cell module is exposed over a long period. Further objects, features, and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings. | 20040407 | 20090519 | 20050106 | 76006.0 | 0 | CARLSON, KOURTNEY SALZMAN | SOLAR CELL MODULE HAVING AN ELECTRIC DEVICE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,819,296 | ACCEPTED | Method and apparatus for efficient data collection | A method and apparatuses are provided for data collection from network elements in a network. A collector sends a data request to one of the network elements. The collector determines whether a condition exists regarding the network element. When the collector determines that the condition exists, the collector stops the data collection from the network element without affecting the data collection by the collector from other network elements, the data collection remains stopped until the collector is notified that the condition no longer exists, and the collector sends a message to the validator to inform the validator of the condition. In another aspect, a validator is informed of a configuration change of one of a group of network elements. The validator requests at least a portion of configuration information of the network element, determines optimum configuration parameters for data collection, and sends the optimum configuration parameters to a collector. | 1. A method for collecting data in a network comprising a plurality of network elements, a collector, and a validator, the method comprising: sending a data request from the collector to one of the plurality of network elements; determining, by the collector, whether a condition exists regarding the one of the network elements; stopping, by the collector, data collection from the one of the plurality of network elements, when the determining determines that the condition exists, without affecting data collection by the collector from other ones of the plurality of network elements, the stopping continuing until the collector is notified that the condition no longer exists, and sending a message, from the collector to the validator, to inform the validator of the condition. 2. The method of claim 1, further comprising: receiving the message by the validator; resolving, by the validator, the condition; sending a second message, from the validator to the collector, informing the collector that the condition is resolved; and receiving the second message by the collector and scheduling, by the collector, a data collection from the one of the plurality of network elements. 3. The method of claim 1, wherein the message is a Simple Network Management Protocol message. 4. The method of claim 1, wherein the condition is one of a configuration change of the one of the plurality of network elements or an inability to contact the one of the plurality of network elements. 5. The method of claim 1, further comprising: receiving, at the validator, the message from the collector informing the validator of the condition, the condition being a configuration change of the one of the plurality of network elements; in response to the receiving the message, performing at the validator: sending one or more requests for at least a portion of configuration information pertaining to the one of the plurality of network elements, receiving the at least a portion of the configuration information, determining a maximum data unit size that can be sent on a path between the collector and the one of the network elements without fragmentation of the data unit, determining a frequency of collection of the data from the one of the network elements; determining a number of data requests to send to the one of the network elements at a sampling time; and sending to the collector information informing the collector that the condition no longer exists, the information including the maximum data unit size, the frequency of collection of the data, and the number of data requests to send to the one of the network elements at the sampling time. 6. The method of claim 1, further comprising: receiving, at the validator, the message from the collector informing the validator of the condition, the condition being an inability to contact the one of the plurality of network elements; in response to the receiving the message, performing at the validator: periodically attempting to reestablish contact with the one of the plurality of network elements, and when the contact with the one of the plurality of network elements is reestablished, sending a second message to the collector informing the connector that the condition no longer exists. 7. The method of claim 6, wherein a probability that the validator can successfully contact the one of the plurality of network elements is equal to a probability that the collector can successfully contact the one of the plurality of network elements. 8. A validator comprising: a memory including a plurality of instructions; and a processor configured to execute the plurality of instructions to: receive an indication from a collector of a condition pertaining to one of a plurality of network elements in a network, resolve a problem associated with the condition, and inform the collector that the problem associated with the condition is resolved. 9. The validator of claim 8, wherein the condition includes one of a configuration change of the one of the plurality of network elements or an inability to contact the one of the plurality of network elements. 10. The validator of claim 8, wherein: the condition is an inability to contact the one of the plurality of network elements, and when the validator resolves the problem associated with the condition, the validator is configured to: attempt to establish contact with the one of the plurality of network elements, when the attempt is unsuccessful, repeat the attempt, and when the attempt is successful, inform the collector that the problem associated with the condition is resolved. 11. A collector for collecting performance data from a plurality of network elements in a network, the collector comprising: a memory including a plurality of instructions; and a processor configured to execute the plurality of instructions to: send a performance data request to each one of the plurality of network elements, receive a performance data response from each one of the plurality of network elements in response to the performance data request, and determine whether a condition exists regarding one of the network elements, when the condition is determined to exist, the processor is further configured to: stop sending of the performance data request to the one of the plurality of network elements without affecting sending of the performance data request to others of the plurality of network elements, and resume sending of the performance data request to the one of the plurality of network elements after being informed that the condition is resolved. 12. The collector of claim 11, wherein the performance data request and the performance data response are Simple Network Management Protocol messages. 13. The collector of claim 11, wherein the condition includes one of a configuration change or an inability to contact the one of the plurality of network elements. 14. The collector of claim 11, wherein: the condition includes a configuration change regarding the one of the plurality of network elements, when the collector is informed that the condition is resolved, the collector changes configuration parameters pertaining to the one of the plurality of network elements, such that a size of a PDU is optimum, within constraints of the system, for collecting the performance data from the one of the plurality of network elements. 15. A validator comprising: a memory including a plurality of instructions; and a processor configured to execute the plurality of instructions to: receive an indication of a configuration change pertaining to one of a plurality of network elements in a network, request and receive at least a portion of configuration information of the one of the plurality of network elements, determine optimum configuration parameters for collecting performance data from the one of the plurality of network elements, and send the optimum configuration parameters to a collector for collecting the performance data from the one of the plurality of network elements. 16. The validator of claim 15, wherein the optimum configuration parameters include at least one item from a group comprising an optimum Protocol Data Unit size for communication with the one of the plurality of network elements, a frequency of collection of the performance data, and a number of data requests to send to the one of the plurality of network elements during each sampling time. 17. The validator of claim 15, wherein when the processor determines the optimum configuration parameters for collecting performance data from the one of the plurality of network elements, the processor is further configured to determine an optimum Protocol Data Unit Size for collecting the performance data by: determining a maximum Protocol Data Unit size configured for the one of the plurality of network elements, determining a smallest Maximum Transmission Unit in a path between the collector and the one of the plurality of network elements, and determining the optimum Protocol Data Unit to be a minimum of the maximum Protocol Data Unit size configured for the one of the plurality of network elements and the smallest Maximum Transmission Unit in the path between the collector and the one of the plurality of network elements. 18. The validator of claim 17, wherein when the processor determines the optimum configuration parameters for collecting the performance data from the one of the plurality of network elements, the processor is further configured to: determine an optimum Protocol Data Unit size for collecting the performance data, determine an amount of available Protocol Data Unit space, determine a maximum amount of the performance data that the Protocol Data Unit can hold, and determine an amount of the performance data to request from the one of the plurality of network elements based on the maximum amount of the performance data that the Protocol Data unit can hold. 19. The validator of claim 18, wherein when the processor determines the optimum configuration parameters for collecting the performance data from the one of the plurality of network elements, the validator is further configured to: determine a time interval between sampling times, and determine a number of data requests to send at each of the sampling times. 20. The validator of claim 15, wherein the processor is further configured to execute the plurality of instructions to: receive an indication from the collector of an inability to contact the one of the plurality of network elements, attempt to establish contact with the one of the plurality of network elements, when the attempt is unsuccessful, repeat the attempt, and when the attempt is successful, inform the collector that the problem associated with the condition is resolved. | TECHNICAL FIELD The invention pertains to computer networks. In particular, the invention pertains to efficient data collection in a network. BACKGROUND OF THE INVENTION Performance metrics may be collected from network elements in a network for a variety of reasons. For example, performance metrics may be collected and processed to determine whether a network provider is providing a certain level of service, such as a level stated in a Service Level Agreement (SLA). FIG. 1 illustrates an exemplary existing system 100 including a network 102, a collector/validator 104 and network elements 106-1, 106-2, 106-3 (collectively referred to as network elements 106) connected to network 102. Collector/validator 104 may request performance metrics from network elements 106. Network elements 106 may be network devices including, for example, host computers, routers, and network nodes. Collector/validator 104 may use the well-known Simple Network Management Protocol (SNMP) to request and receive the metrics from the network elements 106. FIG. 1 is an exemplary existing system and may include more or fewer items than illustrated. For example, system 100 may include multiple collector/validators 104, each collecting performance metrics from a subset of the group of network elements 106. In addition to being responsible for collecting data, such as performance metrics, collector/validator 104 may be responsible for performing other functions, such as validating a configuration change and reestablishing contact with network elements. While collecting performance metrics, if collector/validator 104 cannot establish contact with a network element, collector/validator 104 may attempt to reestablish contact numerous times until the contact is established. Because collection functions, configuration validation functions and contact reestablishment functions of collector/validator 104 share processing resources, collector/validator's 104 configuration validation functions and contact reestablishment functions, in a large network, may have an adverse effect on the collection functions. Thus, in a large network with many configuration changes and frequent loss of contact with network elements 106, uncollected performance metrics may accumulate at network elements 106. When collector/validator 104 is unable to collect the performance metrics from network elements 106 due to inability to contact network elements 106 or time spent performing other functions, network element 106 may use limited storage space or memory to store accumulating performance metrics. Consequently, the longer a time period in which performance metrics are uncollected from a network element 106, the greater the probability of losing performance metric data accumulating in network elements 106. When collector/validator 104 is in a successful steady state and is in the process of collecting performance metrics from network elements 106, using a protocol, such as, for example, SNMP, collector/validator 104 may spend approximately 100 milliseconds (ms) collecting the performance metrics from each of the network elements 106. Of the 100 ms of the collection processing for each network element 106, collector/validator 104 may spend at least 95% of that time requesting the performance metrics. In small networks, overhead associated with a relatively small number of network elements 106 may be negligible. However, in a large network, for example, a network with at least approximately 10,000 nodes, the above-mentioned problems make it necessary to include a number of collector/validators 104 in a network. A more efficient method of collecting performance statistics is needed to decrease the impact of an inability to contact network elements 106 and configuration changes and to decrease the amount of resources, for example, a number of collector/validators 104, needed to collect the performance metrics from network elements 106 in a large network. SUMMARY OF THE INVENTION In a first aspect of the invention, a method is provided for collecting data in a network including a group of network elements, a collector and a validator. In the method, the collector sends a data request to one of the network elements. The collector determines whether a condition exists regarding the one of the network elements. When the collector determines that the condition exists, the collector stops data collection from the one of the network elements without affecting data collection by the collector from other ones of the network elements. The data collection remains stopped until the collector is notified that the condition no longer exists and the collector sends a message to the validator to inform the validator of the condition. In a second aspect of the invention, a validator is provided. The validator includes a memory, including a group of instructions, and a processor. The processor is configured to execute the instructions to receive an indication from a collector of a condition pertaining to one of the network elements in a network, resolve a problem associated with the condition, and inform the collector that the problem associated with the condition is resolved. In a third aspect of the invention, a collector is provided for collecting performance data from a group of network elements in a network. The collector includes a memory, including a group of instructions, and a processor. The processor is configured to execute the instructions to send a performance data request to each one of the network elements, receive a performance data response from each of the network elements, and determine whether a condition exists regarding one of the network elements. When the processor determines that the condition exists, the processor is further configured to stop sending of the performance data request to the one of the network elements without affecting sending of the performance data request to others of the network elements, and resume sending of the performance data request to the one of the network elements after being informed that the condition is resolved. In a fourth aspect of the invention, a validator is provided. The validator includes a memory, including a group of instructions, and a processor. The processor is configured to execute the group of instructions to receive an indication of a configuration change pertaining to one of a group of network elements in a network, request and receive at least a portion of configuration information of the network element, determine optimum configuration parameters for collecting performance data from the network element, and send the optimum configuration parameters to a collector for collecting the performance data from the network elements. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, explain the invention. In the drawings, FIG. 1 depicts an existing system for collecting data from network elements; FIG. 2 depicts an exemplary system, consistent with principles of the invention, for collecting data from network elements; FIG. 3 illustrates a detailed view of an exemplary apparatus that may be used as a collector, a validator, and a network element in implementations consistent with the principles of the invention; FIG. 4 is a flowchart that illustrates an exemplary process for a validator consistent with the principles of the invention; FIG. 5 is a flowchart that illustrates an exemplary process for a collector consistent with the principles of the invention; and FIG. 6 is a flowchart that illustrates another exemplary process for a validator consistent with the principles of the invention. DETAILED DESCRIPTION The following detailed description of the invention refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims and equivalents. As described herein, the collection of data, such as performance metrics, is separated from other network activities, such as contact reestablishment and validation of network element configuration changes. By separating these activities, such as frequent contact reestablishment and validation of network element configuration changes, as may occur in a large network, will not adversely affect the collection of data from unaffected network elements. Exemplary System FIG. 2 depicts an exemplary system 200 consistent with the principles of the invention. System 200 includes a network 202, a collector 204, network elements 206-1, 206-2, 206-3 (collectively referred to as 206), and a validator 208. Collector 204, network elements 206 and validator 208 are connected to network 202. Collector 204 is responsible for collecting data, for example, performance metrics from a group of network elements 206 via network 202. Collector 204 may request and receive the performance metrics from each of the network elements 206 by using the well-known SNMP protocol, or a similar protocol. Validator 208 is responsible for validating configuration changes and for reestablishing contact with network elements 206. Collector 204 and validator 208 may be in separate physical devices or may be in one physical device in which validator 208 and collector 204 operate independently. That is, performance of validator 208 has no effect on collector 204 and vice versa. FIG. 2 is an exemplary system and may include more or fewer items than illustrated. For example, system 200 may include multiple collectors 204, each collecting performance metrics from a subset of the group of network elements 206, or system 200 may include multiple validators 208, each associated with one or more collectors 204. FIG. 3 illustrates a detailed view of a device 300 that may be configured as collector 204, validator 208, or as one of the group of network elements 206. Device 300 may include a bus 310, a processor 320, a memory 330, a read only memory (ROM) 340, a storage device 350, an input device 360, an output device 370, and a communication interface 380. Bus 310 permits communication among the components of device 300. Processor 320 may include one or more conventional processors or microprocessors that interpret and execute instructions. Memory 330 may be a random access memory (RAM) or another type of dynamic storage device that stores information and instructions for execution by processor 320. Memory 330 may also store temporary variables or other intermediate information used during execution of instructions by processor 320. ROM 340 may include a conventional ROM device or another type of static storage device that stores static information and instructions for processor 320. Storage device 350 may include any type of magnetic or optical recording medium and its corresponding drive, such as a magnetic disk or optical disk and its corresponding disk drive. Input device 360 may include mechanisms that permit a user to input information to system 100, such a keyboard, a mouse, a pen, a biometric mechanism, such as a voice recognition device, etc. Output device 370 may include mechanisms that output information to the user, including a display, a printer, one or more speakers, etc. Communication interface 380 may include any transceiver-like mechanism that enables device 300 to communicate via a network. For example, communication interface 180 may include a modem or an Ethernet interface for communicating via network 202. Alternatively, communication interface 380 may include other mechanisms for communicating with other networked devices and/or systems via wired, wireless or optical connections. Device 300 may perform functions in response to processor 320 executing sequences of instructions contained in a computer-readable medium, such as memory 330. A computer-readable medium may include one or more memory devices and/or carrier waves. Such instructions may be read into memory 330 from another computer-readable medium, such as storage device 350, or from a separate device via communication interface 380. Execution of the sequences of instructions contained in memory 330 may cause processor 320 to perform certain acts that will be described hereafter. In alternative implementations, hard-wired circuitry may be used in place of or in combination with software instructions to implement the present invention. Thus, the present invention is not limited to any specific combination of hardware circuitry and software. In one implementation, device 300, configured as collector 204, may be implemented on a NETRA T 1125 computer with twin processors, executing the SOLARIS 2.8 operating system, available from SUN Microsystems. Determination of Optimum Protocol Data Unit and Optimal Sampling Period While in a successful steady state (i.e. a state in which data collection occurs successfully, no loss of contact with network elements 206 occur and no configuration changes of network elements 206 occur), collector 204 may spend a significant amount of time performing network I/O when collecting performance metrics from network elements 206. Therefore, performance of collector 204 may be improved by minimizing the number of collection requests made in any given period within constraints of statistical requirements, counter sizes, performance history depth, etc. A protocol data unit (PDU) is a message of a given protocol that may include payload and protocol-specific control information, typically contained in a header. In implementations consistent with the principles of the invention, the SNMP protocol, or a similar protocol may be used to collect performance metrics. Thus, in some implementations consistent with the principles of the invention, a PDU may be a SNMP protocol message. FIG. 4 is a flowchart that helps to explain a process of determining an optimum PDU size and an optimum sampling period for data collection from a network element. In implementations consistent with the principles of the invention, validator 208 may perform the process when validating a configuration and may reconfigure collector 204 to efficiently collect the performance metrics from the one of network elements 206. This will be discussed in more detail below. Consistent with the principles of the invention, a request for performance metrics and a response including the performance metrics may be included in a PDU within an Internet Protocol (IP) datagram. IP fragmentation occurs when the IP datagram exceeds a length of a Maximum Transmission Unit (MTU) for an interface over which the datagram is about to be transmitted. An MTU is a parameter that determines a largest datagram than can be transmitted via an IP interface without performing IP fragmentation. When a datagram is fragmented, it is not reassembled until it reaches its final destination. Collector 204 of system 200 may reassemble received performance metrics included in fragmented IP datagrams. This is of a particular concern when network element 206 is, for example, a Virtual Private Network (VPN) node, connected to network 202 over a Digital Subscriber Line (DSL), which may have a significantly smaller MTU than a T1 connection. Therefore, in system 200, when validator 208 is validating a configuration change of one of a group of network elements 206, validator 208 may determine the maximum or optimum PDU size for collector 204 to use when collecting the performance metrics from the one of network elements 206 to be a minimum of a maximum PDU size configured for the one of network elements 206 and a smallest MTU (less headers (e.g., IP header and User Datagram Protocol (UDP) header) within a path between collector 204 and the one of network elements 206 (act 402). Once the maximum PDU size is determined, validator 208 may determine an optimum sampling period. The sampling period for one of network elements 206 is a time period between collection of metrics from one of network elements 206 by collector 204. Validator 208 may begin by calculating the amount of PDU space, AV, available for performance metrics by subtracting a size of the PDU header from the maximum PDU size (act 404), as stated in the following formula: AV=MaxPDUSize−PDUHeader (Eq. 1) Typically, at least some of the requested performance metrics may be non-repeatable values, such as, for example, systemUpTime, which indicates an amount of time that the system is up, while other performance metrics may be repeatable, such as performance metrics history data, for example, HistoryCollectionCompletionTime, which indicates the time to complete a most current history collection. Let Cn be a count of required non-repeatable values, Ch be a count of repeatable data, for example, history data, and Ct be a count of a number of sets of performance metrics, for example, Ct may be a number of tunnels associated with one of the network elements 206, where a tunnel is a secure encrypted connection between two points via a public or third party network. Ct may also be, for example, a number of interfaces upon which one of the network elements 206 tracks performance metrics. Validator 208 may calculate an amount of space, S, required for repeatable performance metrics (act 408). In implementations that use the SNMP protocol, responses may include variable names and variable values. Therefore, in such implementations, validator 208 may calculate the amount of required space for repeatable data, S, using the following formula: S = C t × ( ∑ i = 1 C h N i + ∑ i = 1 C h V i ) ( Eq . 2 ) where Ni is a length of an ith variable name and Vi is a length of the ith variable value. Next, validator 208 may calculate an amount of space, SN, required for non-repeatable performance metrics (act 408). In implementations that use the SNMP protocol, validator 208 may calculate an amount of space needed for non-repeatable data, SN, using the following formula: S N = ( ∑ i = 1 C n N i ′ + ∑ i - 1 C n V i ′ ) ( Eq . 3 ) where N′i is a length of an ith non-repeatable variable name and V′i is a length of the ith non-repeatable variable value. Next, validator 208 may calculate the total available PDU space needed for repeatable performance metrics, A′V, by subtracting the space required for non-repeatable data from total available PDU space (act 410). A′V may be determined according to the following formula: A′V=AV−SN (Eq. 4) Validator 208 may perform a calculation to determine whether multiple sets of repeatable performance metrics data may be included in a request for metrics from collector 204 to one of network elements 206 (act 412). If A′V/S≧1 (Eq. 5) then collector 204 may collect multiple repeatable performance metric sets in one data request (one data request includes requests for multiple sets of repeatable performance metrics, Data_requests=1) and the optimal number of requests per hour may be determined (act 414) according to the following formula: Samples(hour)=(60/Pp)×(S/A′V) (Eq. 6) where Pp is a frequency at which unique performance metrics are generated. For example, Pp may be a probing latency metric for a VPN node tunnel. Pp may be set to, for example, 5 minutes. A Management Information Base (MIB) is a database of network management information that is used and maintained by a network management protocol, such as SNMP. The SNMP GetNext operation commands an SNMP agent on a host to get the value of the next object in the MIB. The SNMP GetBulk operation has at least one object identifier as an argument and queries a network entity efficiently for information. The non-repeaters field in the GetBulk PDU specifies the number of supplied variables that should not be iterated over. The max-repetitions field in the GetBulk PDU specifies the maximum number of iterations over the repeating variables. In an implementation in which collector 204 requests and receives performance metrics from network elements 206 via the SNMP protocol, SNMP GetNext or SNMP GetBulk may be used with a repetition count of 1 for non-repeatable values and a repetition count equal to the integer portion of a result of A′V/S. If A′V/S<1, then an amount of performance metric data generated by one of the network elements 206 during a sample period exceeds an amount of available PDU space. Therefore, multiple collection requests may be made by collector 204 to one of the network elements 206 during a sampling period. In an implementation in which collector 204 uses the SNMP protocol to collect performance metrics from a particular one of the network elements 206, validator 208 may calculate the number of SNMP data collection requests per sampling period, Data_requests, (act 416) according to the formula: Data_requests=(S+SN/AV)+x (eq. 7) where x takes into account space needed for variable name/value pairs to be included in a same SNMP PDU. The first request from collector 204 may include non-repeatable values and as many repeatable values as may fit in the remaining PDU space. Subsequent requests from collector 204, for a particular sampling, may exclude prior collected variables. Validator 208 may calculate a total number of sampling periods per hour, Samples(hour), (act 416) as follows: Samples(hour)=(60/Pp) (eq. 8) Exemplary Collector Processing FIG. 5 is a flowchart that illustrates exemplary processing in collector 204 consistent with the principles of the invention. Collector 204 may begin by determining that it is time to collect samples (request performance metrics) from one of the network elements 206. Collector 206 may then request the performance metrics from the network element 206 (act 502). A single set of performance metrics or multiple sets of performance metrics may be requested, as previously discussed with reference to acts 414 and 416 of FIG. 4. After waiting no more than a predetermined time period, collector 204 may determine whether the requested metrics were received (act 504). If the requested metrics were not received, collector 204 may determine whether a number of attempts to collect data from the one of network elements 206 is equal to a predetermined maximum number of retries (act 506). In some implementations consistent with the principles of the invention, the number of retries may be, for example, three. If the number of attempts to collect the metrics from the one of network elements 206 does not equal the maximum number of retries, then collector 204 may again request the metrics from the one of the network elements (act 502). If the number of attempts to collect the metrics equals the maximum number of retries, then collector 204 may send a message to validator 208 to inform validator 208 that collector 204 is unable to contact the one of network elements 206 and collector 204 may remove the one of network elements 206 from a list of network elements 206 from which collector 204 is to collect the metrics (act 508). If the metrics are received, the metrics may include an indication of a configuration change. The indication may include, for example, one or more changed indices or configuration timestamps. If collector 204 determines that the metrics do not include the indication of a configuration change (act 510), then collector 204 may save the collected metrics to a file (act 512). If collector 204 determines that a configuration change has occurred (act 510), then collector 204 may remove the one of the network elements 206 from its list of network elements from which to collect the metrics and collector 204 may send a message to validator 208 informing validator 208 to validate the configuration change of the network element 206 (act 514). Collector 204 may then prepare a request for metrics from a next network element 206 according to collector's 204 list of network elements 206 from which to collect metrics (act 516). Collector 204 may re-perform acts 502-516 for the next network element 206. At some time in the future, validator 206 may reestablish contact with a network element 206 or validator 208 may complete validating a configuration change for a network element 206. When either reestablished contact occurs or a validated configuration change occurs, validator 208 may send a message to collector 204 informing collector 204 of the reestablished contact or the validated configuration change. Upon receiving the message from validator 208, collector 204 may add the network element 206 to collector's 204 list of network elements from which to collect metrics, such that the network element 206 will eventually receive a data request from collector 204. Exemplary Validator Processing FIG. 6 is a flowchart that illustrates exemplary processing performed by validator 208 for one of the group of network elements 206 in implementations consistent with the principles of the invention. Processing may begin with validator 208 receiving a message from collector 204 (act 602). Validator 208 may check the message to determine whether the message indicates that collector 204 is unable to reach a network element 206 (act 604). If validator 208 determines that the message indicates that the network element 206 is unreachable, then validator 208 may periodically attempt to establish contact with the network element 206. When contact is established, validator 208 may send a message to collector 204 to inform collector 204 that the network element 206 is now reachable (act 608). Ideally, validator 208 should be located such that a probability of contacting network elements 206 from validator 206 is the same as a probability of contacting network elements 206 from collector 204. Otherwise, validator 208 may report contact established and collector 204 may immediately report an inability to contact. The repeating of the reporting of the contact established and the inability to contact sent from validator 208 to collector 204 may adversely affect collection performance of collector 204. When validator 208 determines that the message received from collector 204 does not indicate that a particular one of network elements 206 is unreachable, validator 208 may assume that the message indicates that a configuration change has occurred. Validator 208 may then obtain relevant portions of a configuration from the network element 206 or from a configuration management server (act 610). In implementations in which validator 208, collector, 204 and network elements 206 communicate via the SNMP protocol or a similar protocol, validator 208 may request the relevant configuration information via the protocol. For example, validator 208 may request information regarding, for example, maximum configured PDU size at one of network elements 206, MTU sizes along paths between collector 204 and the network element 206, frequency, Pp, at which the network element 206 generates performance metrics, count of repeatable data, length of repeatable variable names, length of repeatable variable values, length of non-repeatable variable names, length of non-repeatable variable values, and a number of sets of performance metrics, Ct, associated with the network element 206. If validator 208 is unable to obtain the relevant portions of the configuration, which may be due to an invalid network element configuration, validator 208 may provide a warning. The warning may be, for example, a message on a display or in a report, an e-mail message sent to a system administrator, or any other method of providing a warning. After obtaining the relevant configuration information, validator 208, may calculate sampling period, samples(hour), and a number of collection requests per sample, Data_requests (act 612). Validator 208 may perform the calculations as described previously (acts 402-416: FIG. 4). Validator 208 may then send a message, using SNMP or a similar protocol, to collector 204, to inform collector 204 that configuration validation is complete for the network element 206 and to inform collector 204 of any relevant changes, such as, for example, a change in number of requests per sample, a change in PDUSize, a change in sampling time, a change in number of tunnels, etc. (act 614). When collector 204 receives the message indicating the completion of validation from validator 208, collector 204 may change relevant configuration parameters pertaining to collection from the network element 206, for example, sampling time, PDUSize, number of requests per sample, etc. and may add the network element 206 to the list of network elements 206 from which collector 204 is to collect metrics. Similarly, when collector 204 receives a contact established message for one of the network elements 206 from validator 208, collector 204 may add the network element 206 to the list of network elements 206 from which collector 204 is to collect metrics. Conclusion Removing non-collection activities, such as configuration validation and contact reestablishment, from a collector minimizes the performance impact on data collection when numerous network elements become unreachable and when configuration changes of network elements occur. In an existing system with about 10,000 network elements, seven collector/validators, each having twin CPU hosts, collected metrics from the network elements at 30-minute intervals. After implementing an embodiment consistent with the principles of the invention, a single twin CPU host collector was able to collect metrics from about 10,000 network elements at ten minute sampling intervals. The foregoing description of the preferred embodiments of the present invention are provided for illustration and description, but is not intended to be limiting or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. For example, while series of acts have been described with regard to FIGS. 4-6, the order of the acts may differ in other implementations consistent with the present invention. Also, non-dependent acts may be performed in parallel. No element, act or instruction used in the description of the present application should be construed as critical or essential to the invention unless explicitly described as such. Also, as used herein, the article “a” is intended to include one or more items. Where only one item is intended, the term “one” or similar language is used. The scope of the invention is defined by the claims and their equivalents. | <SOH> BACKGROUND OF THE INVENTION <EOH>Performance metrics may be collected from network elements in a network for a variety of reasons. For example, performance metrics may be collected and processed to determine whether a network provider is providing a certain level of service, such as a level stated in a Service Level Agreement (SLA). FIG. 1 illustrates an exemplary existing system 100 including a network 102 , a collector/validator 104 and network elements 106 - 1 , 106 - 2 , 106 - 3 (collectively referred to as network elements 106 ) connected to network 102 . Collector/validator 104 may request performance metrics from network elements 106 . Network elements 106 may be network devices including, for example, host computers, routers, and network nodes. Collector/validator 104 may use the well-known Simple Network Management Protocol (SNMP) to request and receive the metrics from the network elements 106 . FIG. 1 is an exemplary existing system and may include more or fewer items than illustrated. For example, system 100 may include multiple collector/validators 104 , each collecting performance metrics from a subset of the group of network elements 106 . In addition to being responsible for collecting data, such as performance metrics, collector/validator 104 may be responsible for performing other functions, such as validating a configuration change and reestablishing contact with network elements. While collecting performance metrics, if collector/validator 104 cannot establish contact with a network element, collector/validator 104 may attempt to reestablish contact numerous times until the contact is established. Because collection functions, configuration validation functions and contact reestablishment functions of collector/validator 104 share processing resources, collector/validator's 104 configuration validation functions and contact reestablishment functions, in a large network, may have an adverse effect on the collection functions. Thus, in a large network with many configuration changes and frequent loss of contact with network elements 106 , uncollected performance metrics may accumulate at network elements 106 . When collector/validator 104 is unable to collect the performance metrics from network elements 106 due to inability to contact network elements 106 or time spent performing other functions, network element 106 may use limited storage space or memory to store accumulating performance metrics. Consequently, the longer a time period in which performance metrics are uncollected from a network element 106 , the greater the probability of losing performance metric data accumulating in network elements 106 . When collector/validator 104 is in a successful steady state and is in the process of collecting performance metrics from network elements 106 , using a protocol, such as, for example, SNMP, collector/validator 104 may spend approximately 100 milliseconds (ms) collecting the performance metrics from each of the network elements 106 . Of the 100 ms of the collection processing for each network element 106 , collector/validator 104 may spend at least 95% of that time requesting the performance metrics. In small networks, overhead associated with a relatively small number of network elements 106 may be negligible. However, in a large network, for example, a network with at least approximately 10,000 nodes, the above-mentioned problems make it necessary to include a number of collector/validators 104 in a network. A more efficient method of collecting performance statistics is needed to decrease the impact of an inability to contact network elements 106 and configuration changes and to decrease the amount of resources, for example, a number of collector/validators 104 , needed to collect the performance metrics from network elements 106 in a large network. | <SOH> SUMMARY OF THE INVENTION <EOH>In a first aspect of the invention, a method is provided for collecting data in a network including a group of network elements, a collector and a validator. In the method, the collector sends a data request to one of the network elements. The collector determines whether a condition exists regarding the one of the network elements. When the collector determines that the condition exists, the collector stops data collection from the one of the network elements without affecting data collection by the collector from other ones of the network elements. The data collection remains stopped until the collector is notified that the condition no longer exists and the collector sends a message to the validator to inform the validator of the condition. In a second aspect of the invention, a validator is provided. The validator includes a memory, including a group of instructions, and a processor. The processor is configured to execute the instructions to receive an indication from a collector of a condition pertaining to one of the network elements in a network, resolve a problem associated with the condition, and inform the collector that the problem associated with the condition is resolved. In a third aspect of the invention, a collector is provided for collecting performance data from a group of network elements in a network. The collector includes a memory, including a group of instructions, and a processor. The processor is configured to execute the instructions to send a performance data request to each one of the network elements, receive a performance data response from each of the network elements, and determine whether a condition exists regarding one of the network elements. When the processor determines that the condition exists, the processor is further configured to stop sending of the performance data request to the one of the network elements without affecting sending of the performance data request to others of the network elements, and resume sending of the performance data request to the one of the network elements after being informed that the condition is resolved. In a fourth aspect of the invention, a validator is provided. The validator includes a memory, including a group of instructions, and a processor. The processor is configured to execute the group of instructions to receive an indication of a configuration change pertaining to one of a group of network elements in a network, request and receive at least a portion of configuration information of the network element, determine optimum configuration parameters for collecting performance data from the network element, and send the optimum configuration parameters to a collector for collecting the performance data from the network elements. | 20040407 | 20090630 | 20051013 | 70899.0 | 0 | TRAN, PHILIP B | METHOD AND APPARATUS FOR EFFICIENT DATA COLLECTION | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,819,395 | ACCEPTED | Low noise amplifier for wireless communications | A low noise amplifier is provided for the receiver of a wireless communications system. The amplifier incorporates an image rejection function by incorporating a notch filter formed by an inductor and capacitor connected at a node between two active elements of the amplifier. The amplifier also incorporates a gain control function by adding a further active element connected to, on one hand, a node between the inductor and capacitor and, on the other hand, a voltage supply. A gain control signal is connected to the control input of the further active element has an input connected to a feedback lead of the receiver to provide the gain control. | 1. A low noise amplifier for a wireless communication system, comprising: an arrangement of active elements forming an amplifier having a signal input and a bias input and a signal output; an interconnection node between two of said active elements; an inductive element connected at one end to said interconnection node; and a capacitance element connecting another end of said inductive element to ground, said inductive element and said capacitance element being selected to provide a notch filter for substantially reducing an amplitude of a predetermined frequency from a signal at said signal output. 2. A low noise amplifier as claimed in claim 1, further comprising: a further active element connected to an interconnection node between said inductive element and said capacitance element, said further active element connected between said active elements and a supply voltage and having a connection to a control signal at an control input. 3. A low noise amplifier as claimed in claim 2, further comprising: a control element connected to said control input of said further active element. 4. A low noise amplifier as claimed in claim 3, wherein said control element is a controllable voltage source. 5. A low noise amplifier as claimed in claim 1, wherein said active elements are first and second field effect transistors connected to one another with a source and drain path of said first field effect transistor connected to a source and drain path of said second field effect transistor. 6. A low noise amplifier as claimed in claim 5, further comprising: inductor elements connected in series with said source and drain paths of said first and second transistors, said inductor elements and said first and second transistors being connected between a voltage supply and ground. 7. A low noise amplifier as claimed in claim 1, wherein said low noise amplifier is configured to operate at approximately 915 MHz. 8. A low noise amplifier as claimed in claim 1, wherein said predetermined frequency is an image frequency. 9. A low noise amplifier as claimed in claim 1, wherein said inductive element is a spiral inductor and said capacitive element is a metal-insulator-metal capacitor. 10. A low noise amplifier as claimed in claim 9, wherein said active elements are integrated on a semiconductor chip and said spiral inductor and said metal-insulator-metal capacitor are integrated on said same chip. 11. A low noise amplifier as claimed in claim 10, further comprising: a further active element connected to an interconnection node between said inductive element and said capacitance element, said further active element connected between said active elements and a supply voltage and having a connection to a control signal at an control input, said further active element being integrated on said same semiconductor chip with said active elements. 12. A low noise amplifier as claimed in claim 1, wherein said active elements are integrated on a semiconductor chip and said inductive element and said capacitance element are integrated on said same chip. 13. A low noise amplifier as claimed in claim 12, further comprising: further inductive elements connected to said active elements, said further inductive elements being enclosed within a housing of said semiconductor chip. 14. A low noise amplifier as claimed in claim 1, wherein said low noise amplifier is configured to operate at radio frequencies according to at least one of the standards selected from Zigbee, Wi-Fi and Bluetooth. 15. A low noise amplifier as claimed in claim 1, wherein said active elements include a common source transistor and common gate transistor, said common source transistor having a parasitic capacitance, said inductive element being of an inductance value to substantially cancel said parasitic capacitance. 16. A low noise amplifier as claimed in claim 1, wherein said active elements include a first transistor having a control lead connected to receive said input signal, said active elements include a second transistor having a control lead connected to receive said bias input. 17. A low noise amplifier for use in a wireless communications system, comprising: a first transistor having a control input connected to receive an input signal and having second and third leads; a second transistor having a control input connected to receive a bias voltage and having second and third leads, said third lead of second transistor being connected to said second lead of said first transistor at an interconnection node; a first inductor connected between said control input of said first transistor and a signal input for said low noise amplifier; a second inductor connected between said third lead of said first transistor and ground; a third inductor connected between said second lead of said second transistor and a supply voltage; a first capacitive element connected between said second lead of said second transistor and an output of said low noise amplifier; a fourth inductor connected to said interconnection node between said first and second transistors, said fourth inductor having an opposite end at a second interconnection node; and a second capacitive element connected between said second interconnection node and ground. 18. A low noise amplifier as claimed in claim 17, further comprising: a third active element having a second lead connected between said second lead of said second transistor and having a third lead connected to said second interconnection node, said third active element having a control input. 19. A low noise amplifier as claimed in claim 18, further comprising: a control voltage connected between to said control input of said third active element. 20. A low noise amplifier as claimed in claim 18, wherein said first and second and third active elements and said fourth inductor and said second capacitive element are integrated on a semiconductor chip. 21. A low noise amplifier as claimed in claim 20, wherein said semiconductor chip is constructed in CMOS technology. 22. A low noise amplifier as claimed in claim 17, further comprising: a third capacitive element connected between said control input of said first active element and said third lead of said first active element. 23. A low noise amplifier as claimed in claim 17, wherein said low noise amplifier is configured to operate in a frequency range of 400 Mhz to 5900 MHz. 24. A low noise amplifier as claimed in claim 23, wherein said low noise amplifier is configured to operate at a frequency of about 915 MHz. 25. A low noise amplifier for use in a wireless communications system receiver, comprising: a first transistor having a control input connected to receive an input signal and having second and third leads; a second transistor having a control input connected to receive a bias voltage and having second and third leads, said third lead of second transistor being connected to said second lead of said first transistor at an interconnection node; a first inductor connected between said control input of said first transistor and a signal input for said low noise amplifier; a second inductor connected between said third lead of said first transistor and ground; a third inductor connected between said second lead of said second transistor and a supply voltage; a first capacitive element connected between said second lead of said second transistor and an output of said low noise amplifier; a fourth inductor connected to said interconnection node between said first and second transistors, said fourth inductor having an opposite end at a second interconnection node; and a second capacitive element connected between said second interconnection node and ground. 26. A low noise amplifier for use in a wireless communications system receiver as claimed in claim 25, further comprising: a third active element having a second lead connected between said second lead of said second transistor and having a third lead connected to said second interconnection node, said third active element having a control input. 27. A low noise amplifier for use in a wireless communications system receiver as claimed in claim 26, further comprising: a control voltage connected between to said control input of said third active element. 28. A low noise amplifier for use in a wireless communications system receiver as claimed in claim 26, wherein said first and second and third active elements and said fourth inductor and said second capacitive element are integrated on a semiconductor chip. 29. A low noise amplifier for use in a wireless communications system receiver as claimed in claim 28, wherein said semiconductor chip is constructed in CMOS technology. 30. A low noise amplifier for use in a wireless communications system receiver as claimed in claim 25, further comprising: a third capacitive element connected between said control input of said first active element and said third lead of said first active element. 31. A low noise amplifier for use in a wireless communications system receiver as claimed in claim 25, wherein said low noise amplifier is configured to operate in a frequency range of 400 MHz to 5900 MHz. 32. A low noise amplifier for use in a wireless communications system receiver as claimed in claim 31, wherein said low noise amplifier is configured to operate at a frequency of about 915 MHz. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to an amplifier for use in a wireless communication system, and in particular to a low noise amplifier for use in a radio frequency receiver. 2. Description of the Related Art With the explosive growth in the commercial wireless telecommunications market, a greater need is seen for lower cost and more highly integrated telecommunications equipment. Integrated semiconductor devices provide the possibility of meeting both needs. For example, silicon based devices may provide the necessary characteristics to address a wide range of applications. CMOS (Complementary Metal Oxide Semiconductor) technology is becoming feasible for high frequency analog applications that were traditionally built with more expensive technologies such as bipolar devices. Sub-micrometer CMOS technologies now exhibit sufficient performance for RF (Radio Frequency) applications in a few gigahertz ranges. However, using a standard CMOS technology, the design of amplifiers for use at high frequencies requires more detailed considerations than those for use at low frequencies. In FIG. 1 is shown a super-heterodyne architecture of the type that is widely used in modem wireless communications handsets. The receiver includes an antenna 10 having an output connected to a radio frequency (RF) filter 11. The filter output is connected to a low noise amplifier 12 that in turn is connected to an image filter 13. The image filter 13 output is fed to a mixer 14 which has a second input connected to a local oscillator (LO) signal 15. The output of the mixer 14 is provided to an intermediate frequency (IF) filter 16. The output of the IF filter is used in the communications system in a way that is well known. This architecture is capable of providing high reliability and stable performance in mobile communications. In super-heterodyne receivers, the image frequency presents a problem because the image frequency is superimposed on the desired signal. In order to solve this problem and provide removal, or rejection, of the image frequency signal, the super-heterodyne receiver front-end can consist of any of several topologies. Especially useful approaches are the use of an image rejection filter component in a Hartley architecture or a Weaver architecture. Modem radio frequency receivers are often provided on a semiconductor chip to provide the advantages of lower cost, greater compactness and reduced power consumption. The chip is indicated in FIG. 1 by the solid line 18 enclosing the low noise amplifier 12, local oscillator 15, mixer 14 and IF filter 16. Currently, most of the commercially available radio frequency receivers use off-chip passive bandpass filters, such as ceramic or surface acoustic wave (SAW) filters, because the off-chip filters provide the most robust solution to the image rejection problem. As has been well known for years, surface acoustic wave bandpass filters have a number of advantages, for example, no power consumption, no linearity degradation, and extraordinarily high quality factor. However, the high cost and large size of such separate bandpass filters make these filters less attractive for use in the next generation receivers. The conventional receiver system of FIG. 1 uses an external filter for image rejection. Specifically, the RF filter 11 and image filter 13 are provided as external components to the chip 18. The current, off-chip passive filters, such as surface acoustic wave filters or ceramic filters, are used for image frequency rejection, but these bulky filters are the major impediment to raising the level of integration of the radio frequency circuit since they cannot be easily integrated. Systems using these filters have a relatively high cost and large size. Therefore, to decrease the circuit size, monolithic integration of the filter with the other electrical devices of the receiver circuit is being researched. In applications for use at frequencies below 3 GHz, monolithic circuits are provided using an image rejection mixer for phase cancellation to satisfy an image rejection specification of better than 41 dB. Practical systems require higher values of image rejection. As such, it would be desirable to combine an on-chip image filter with an integrated image reject mixer to obtain a very high on-chip image rejection. When a wide range of signal powers is received by an antenna in a wireless communications system, the system requires the addition of a variable gain stage. The variable gain function is generally provided in later stages in the radio receiver system. For example, in FIG. 2 is provided a variable gain amplifier 17 at the output of the IF filter 16. The variable gain amplifier includes a control lead 18, as is well known, for controlling the output gain of the variable gain stage to compensate for changes in the power of the received signal. If the variable gain function is provided at the early stages in the system such as using a low noise amplifier (LNA) 12 a such as shown in FIG. 2, then the gain variation is being made in the presence of minimum power signals and the signal-to-noise ratio increases. If instead the gain control is provided later in the receiver system while in the presence of maximum power signals, the last stage of the receiver is not saturated. Furthermore, with such gain controllable low noise amplifiers (LNA), the target dynamic range of the VGA (Variable Gain Amplifier) 20 tends to be degraded. A low noise amplifier (LNA) is used in the RF receiver in a wireless communication application to obtain the necessary power gain and decreasing the noise factor (NF). Conventional low noise amplifiers have high power consumption at radio frequencies to satisfy the required power gain and to provide the characteristics necessary in an RF receiver application. The conventional LNA uses a one unit common source amplifier structure as shown in FIG. 3 configured as a cascode amplifier. In particular, the amplifier circuit of FIG. 3 includes a first FET 45 connected with a gate inductor 46 at its gate lead, through which is fed the input signal of the amplifier circuit. The source of the FET 45 is connected through a source inductor 47 to ground. The drain of the FET 45 is connected to a source of a second FET 43 at a node 44. The drain of the second FET 43 is connected through a drain inductor 41 to the supply voltage VDD. A bias voltage Vbias is connected at the gate of the second FET 43. A capacitor 42 is connected to the drain of the second FET 43 as well to provide the output signal for the amplifier through the capacitor. Operationally, in FIG. 3 in order to achieve low noise and to provide power matching at the same time, the source inductor 47, also denoted Ls in the drawing, is used. When an inductor having a high quality factor is used for this source degeneration function, the result is that the amplifier has good noise performance. The bonding wire to the chip has been used as the inductor for source degeneration, and its length is selected by considering a minimum size at for the chip layout and for bonding. The drain inductor 41, also denoted Ld, the source inductor 47 and the gate inductor 46, also denoted Lg in the drawing, as well as the capacitor 42, also denoted C1, are external elements. The gate inductor 46 and the source inductor 47 are used for matching input impedance, and the drain inductor 41 and capacitor 42 are used for matching output impedance. The bias signal Vbias is supplied to the gate of the transistor 43, also denoted M2 on the drawing. The elements within the dashed line are on the chip. In this structure, the signal is amplified by the gain of the cascode structure of the two transistors 45 and 43. Amplifiers of this type are used in wireless communications. Wireless communications systems have exhibited remarkable growth over the past decade. Wireless voice and data applications are being enabled by rapidly emerging wireless technologies, such as cellular telephony, personal communications systems and wireless local area network (WLANs), to name a few. Digital modulation techniques, miniaturization of transceivers due to advances in monolithic integrated circuit design and the development of high frequency, microwave and millimeter wave RF systems in both the licensed and unlicensed bands have all contributed to improving the quality and bandwidth capacity of these systems and to reducing the size and costs of the components. The LNA (Low Noise Amplifier) is a critical front end component of a wireless receiver. As noted above, its function is to take the relatively weak signal received at the antenna and, after filtering of the signal, amplify it with maximum power transfer and with a minimum of added noise for further processing (referred to as down conversion, etc.). The maximum power transfer is achieved by designing the LNA to have an input impedance that matches a characteristic input impedance of the antenna, which is commonly 50 ohms. Thus, a true concurrent LNA, as a critical front end component of a concurrent receiver, must be capable of (1) matching the characteristic input impedance of the received signal at the antenna at the respective frequency band; (2) simultaneously amplifying the received signal(s); and (3) accomplishing the above with minimum added electrical noise. SUMMARY OF THE INVENTION The present invention provides a LNA (Low Noise Amplifier) for use at radio frequencies in a wireless communication system, the amplifier preferably being used in an early stage of the wireless receiver and having a low noise characteristic. In one embodiment, the amplifier has a cascode configuration and includes an added inductor at a node between the two active elements to cancel parasitic capacitance and thereby cancel high frequency leakage. Further embodiments utilize the added inductor as part of a filter section to provide filtering of the image frequency from the radio signal. The previously mentioned inductor functions in combination with an added capacitor to provide this image rejection. In yet further embodiments, the present low noise amplifier includes an added gain controller to simultaneously provide, in a preferred embodiment, image rejection and gain control functions in a low noise amplifier. The gain controller is provided by an active element, such as a FET (Field Effect Transistor) at the gate of which is connected a control signal. An added benefit of the preferred embodiment is that noise contributions are reduced compared to the core LNA cascode amplifier device. In addition, the gain control improves the input linearity of front-end circuit in the presence of large signals. The present low noise amplifier is used for wireless communications systems, including wireless communications at 915 MHz according to the Zigbee (section 802.15.4) standard as well as for wireless communications systems using Wi-Fi or Bluetooth (section 802.11 a, b and g) standards, GSM systems, CDMA, TDMA, packet data systems, etc. BRIEF DESCRIPTION OF THE DRAWINGS The features of the present invention will become more apparent from the description given in further detail hereinbelow with reference to the accompanying drawings. FIG. 1 is functional block diagram of a super-heterodyne receiver circuit having with an external filter for image rejection, according to the prior art; FIG. 2 is a functional block diagram of a receiver system showing voltage gain control both early in the system and later; FIG. 3 is a circuit diagram of a conventional cascode amplifier; FIG. 4 is circuit diagram of a low noise amplifier according to the principles of the present invention; FIG. 5 is a circuit diagram of an equivalent circuit of impedance Zb at node B of FIG. 4; FIG. 6 is a graph of an imaginary part of impedance of only a filter portion of the present circuit; and FIG. 7 is a logarithmic scale of impedance Zb at node B of FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides an improvement over the conventional cascode amplifier that is used in a radio frequency receiver communication system. The present low noise amplifier eliminates the need for an external image rejection filter from the receiver circuit so that there is no longer a requirement for an off-chip filter for image rejection. This enables a higher level of integration, a more compact circuit and lower costs. The circuit of one embodiment of the present low noise amplifier is shown in FIG. 4. The amplifier, like the amplifier of FIG. 3, has two FETs (Field Effect Transistors) connected to one another. Here, FETs 52 and 57 are provided. The present invention recognizes that the low noise amplifier of FIG. 3 generates a signal leakage due to the parasitic capacitance of node 44, also denoted node A in the figure. In order to solve this signal leakage problem, the first improvement of the LNA topology provides a resonance inductor connected at node A to cancel the parasitic capacitor. The added inductor is indicated by reference character 54 in FIG. 4, and also denoted L1 in the figure. A further improvement is added in the circuit of FIG. 4; specifically, the capacitor 59, also denoted C2, is added between the opposite end of the inductor 54 and ground to provide filtering. By choosing the relative values of the inductor 54 and capacitor 59, a notch filter is provided to remove the image frequency signal which plagues super-heterodyne receivers. In yet a further improvement realized in the present invention, the amplifier circuit has an added FET 60 connected with its source and drain path connected at one end between the supply voltage and the drain of the transistor 52 and at the other end to the capacitor 59. In the illustrated embodiment, the connection of the transistor 60 is between the drain inductor 51 and the voltage supply. This has the effect of shutting off the transistors 52 and 57 as the transistor 60 is switched on, thereby providing the gain control using the low noise amplifier circuit. A control is connected to the gate of the FET 60 to vary the current flow through the FET 60. In the preferred embodiment, the control is a voltage control 67. The voltage control 67 is derived from the same source as the variable control signal used to provide gain control in the known variable gain receiver circuit. As such, the control voltage is well known in the art and need not be addressed further here. In the circuit of FIG. 4, the inductors 55, 58 and 51 and the capacitor 53 are external elements, while the remaining elements are integrated on a chip. Specifically, in the preferred embodiment, the inductors 55, 58 and 51 and the capacitor 53 are provided within the housing of the semiconductor chip, although not on the chip itself. These elements are provided by the lead wires connecting the semiconductor chip body to connector pads within the chip housing. The inductors 55 and 58 are used for matching input impedance, and inductor 51 and capacitor 53 are used for matching output impedance. An additional capacitor 56 is provided at the gate-source connection of the first transistor to provide input matching stability. In this structure, the input signal is represented as a series connected inductor 55 and the output signal is represented as a series connected capacitor 53. The transistors 57 and 52 provide the amplification function and are connected in a cascode amplifier configuration. The transistor 60 is used as the gain control amplifier. The input signal on the line 65 is input to the cascode amplifier. The value of the inductor 55 is selected to assist the amplifying transistor 57 in achieving improved gain and a better noise figure. The drain of the transistor 52 is connected to the voltage signal Vdd through the inductor 51 and the drain of the transistor 60 is also connected to the voltage signal Vdd. The entire gain is obtained by multiplying of the gain of cascode amplifier and common source amplifier. The input signal is amplified according to the gain of the cascode structure composed of the transistor 52 through coupling to the gate of the common source transistor 57 by capacitor 56. The drain of the common source transistor 52 is connected to the output. The inductance 54 connected between a drain of the transistor 57 and the source of the transistor 60. The capacitance 59 is connected to the source of the transistor 60. The inductance 54 and capacitance 59 operate as a notch filter. A proper selection of the inductor 54 and the capacitor 59 can reduce the signal leakage and provides a substantial reduction in the amplitude of the signal at the image frequency that can be occurred at the node B 61. This technique of forming a notch filter for removing the image frequency also provides an improved noise figure performance for the LNA. The inductor 54 is an on-chip spiral inductor. In order to obtain much higher quality factor, the spiral inductor is designed with a thick top metal layer. The capacitor 59 is also integrated into the chip, using for example MIN (metal-insulator-metal) capacitor methods. Integration of these elements in the chip lowers costs of the circuit, reduces the size of the circuit by a considerable amount, and provides a high efficiency and low noise circuit. In addition to the image rejection function, in order to provide gain control to the LNA, this invention proposes a new LNA topology, which allows DC bleeding current in the circuit as shown in FIG. 4. In FIG. 4, the impedance Zb 64 which is the impedance looking to the node B 61 can be presented as an equivalent circuit as shown in FIG. 5. As can be seen in the equivalent circuit, the capacitor Cpar 72 is the overall parasitic capacitance at node B 61, the capacitor Ceq 74 is the sum between the capacitor 59 and the overall parasitic capacitor at node C 62 in FIG. 4. The resistance 1/gm 71 is the transconductance of the transistor 52. In order to characterize effect of the filter in FIG. 4, the impedance Zb is determined by: Zb ( S ) = S 2 L 2 Ceq + 1 S ( S 2 CparL 2 Ceq + Cpar + Ceq ) eq . ( 1 ) From the equation eq(1), it can be seen that the filter has imaginary zeros and poles at f image = 1 2 π L 2 Ceq And eq . ( 2 ) f wanted = 1 2 π 1 L 2 ( 1 Cpar + 1 Ceq ) eq . ( 3 ) Where fimage and fwanted are frequencies of the wanted, or desired, image signal and interest signal respectively. From equations eq(2) and eq(3), in order to increase the image rejection effect, the inductor 73 and the capacitors Cpar and Ceq should have high quality factors. Operationally, the present low noise amplifier operates by direct conversion rather than as a super-heterodyne receiver. In one example of the circuit for use at 915 MHz according to the Zigbee standard, the elements have approximately the following values: the inductor 55 is 34 nH, the capacitor 56 is 1 pF, the inductor 58 is 430 pH, the inductor 51 is 9 nH, the capacitor 53 is 0.7 pF, the inductor 54 is 1 nH, the capacitor 59 is 1 pF, the range of the control voltage output by the gain control element 67 is in a range of 0 to 1 volt, the field effect transistors 52 and 57 are NMOS transistors, and the field effect transitor 60 is a PMOS transistor. FIG. 5 shows the imaginary part of impedance of only filter. At low frequencies, the filter has capacitor characteristic but inductor characteristic at high frequency. The resonance point of filter of FIG. 6 indicates the frequency of the image rejection designed from equation eq(2). In FIG. 6, the log scale of the impedance Zb at node B of FIG. 4 is shown as an intersection of frequency and an imaginary impedance. The intersection is indicated as a line and a point on the line at the frequency in question indicates a resonance point of the filter. As can be seen from FIG. 7, the response curve of the amplifier in the area of the wanted frequency is generally flat while the response curve at the image frequency has sharp decrease in the response. The image frequency is removed from the output signal so that an image rejection filter is not needed later in the receiver circuit. The reason for the response is reversed of the transconductance gm2 of FIG. 7. The filters operated as a series resonance circuit, is not independent on the reverse of the transconductance gm2. But the parallel resonance circuit at the wanted frequencies depends on the reverse of the transconductance gm2. The current determined by the transconductance stage flows into the transistor 52 and 60. The transistors 52 and 60 are switched by the gate bias of the transistor 60 and one of the transistors is turned on. If the transistor 52 turns on, the current switch gain control amplifier acts as an usual cascade amplifier and has a high gain, while if the transistor 60 turns on most RF power is thrown away into Vdd through the transistor 60 and it leaks only the little power set by the isolation characteristic of the transistor 52 to the output. In order to reduce the noise contribution, the small width of transistor 60 bleeding current should be selected. In equation eq(2), the image frequency is related to intermediate frequency in subsequent mixer. Since the filtering at image frequency means the leakage, the noise performance is bad at this frequency. Therefore, the tail of filtering can increase e the noise figure at the wanted frequency. The half of the tail width of filtering must be larger than the intermediate frequency of the mixer. Thus, the present low noise filter eliminates the need for a separate gain control in the receiver circuit and also eliminates the need for a separate notch filter in the receiver circuit. All this is possible while increasing the level of integration of the low noise amplifier. The present invention provides not just an add-on to an existing amplifier structure, but a combination of elements assembled in such a way as to achieve a new result. The present amplifier is used, for example, for a 915 MHz receiver system of a wireless communication in CMOS technology. The present amplifier may, however, be used in wireless communications systems operating at frequencies of from 400 MHz up to as much as 5900 MHz. In order to improve the image rejection characteristics of the amplifier, the amplifier uses a notch filter composed of a spiral inductor and capacitor. The elements of the filter should have a high quality factor in order to make sharp bandwidth notch. So, using the spiral inductor with higher quality factor instead of another type of inductor and using a MIM (metal-insulator-metal) capacitor that are fabricated together, the notch filter with a narrow bandwidth is achieved. Furthermore, since attaching the filter at the midpoint of the cascode topology connected transistors reduces leakage due to parasitic capacitance, the noise figure at interest frequency can be enhanced. In addition to gain control function, the input linearity of system is enhanced. Since a low noise amplifier with only an amplification function located at a stage is going before the mixer in the receiver system, a large signal to input of the receiver can be saturated at following stage. The low noise amplifier of the preferred embodiment is characterized wherein in order to provide image rejection for a 915 MHz receiver system, it uses a spiral inductor 54 and MIM capacitor 59 as a notch filter. The inductance of the notch filter added to LNA cancels the parasitic capacitance generated between common source and common gate transistor. Therefore, the leakage due to the parasitic capacitance can be reduced and the noise performance of the LNA is improved. The preferred low noise amplifier is further characterized wherein order to provide gain control, the transistors 52 and 60 are switched by the gate bias of a transistor 60 and one of the transistor is turned on. The current switch gain control amplifier acts as an usual cascade amplifier and has a high gain, while if the transistor 60 turn on most RF power is thrown away into the supply voltage Vdd through the transistor 60. Thus, the present low noise amplifier of the preferred embodiment provides the advantages of eliminating the need for an off-chip image rejection filter and eliminating the need for a separate gain control. The amplifier provides an improved noise performance. The amplifier is preferably integrated on the semiconductor chip using CMOS technology. A particular application for the present low noise amplifier is in the early stages of a receiver circuit for the 915 MHz wireless communications according to the section 802.15.4 standard (referred to as Zigbee). Application in other wireless communications systems is of course possible. For example, the Bluetooth and Wi-Fi communications systems according to sections 802.11 a, b or g would benefit from the present low noise amplifier. Wireless Local Area Networks (WLANs) or various packet data transmission systems, GSM communications, so-called 3G systems, etc. may also use the principles in the present invention. Of course, other applications both within wireless communications and outside the wireless communications field are possible and are encompassed within the present invention. Although other modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates generally to an amplifier for use in a wireless communication system, and in particular to a low noise amplifier for use in a radio frequency receiver. 2. Description of the Related Art With the explosive growth in the commercial wireless telecommunications market, a greater need is seen for lower cost and more highly integrated telecommunications equipment. Integrated semiconductor devices provide the possibility of meeting both needs. For example, silicon based devices may provide the necessary characteristics to address a wide range of applications. CMOS (Complementary Metal Oxide Semiconductor) technology is becoming feasible for high frequency analog applications that were traditionally built with more expensive technologies such as bipolar devices. Sub-micrometer CMOS technologies now exhibit sufficient performance for RF (Radio Frequency) applications in a few gigahertz ranges. However, using a standard CMOS technology, the design of amplifiers for use at high frequencies requires more detailed considerations than those for use at low frequencies. In FIG. 1 is shown a super-heterodyne architecture of the type that is widely used in modem wireless communications handsets. The receiver includes an antenna 10 having an output connected to a radio frequency (RF) filter 11 . The filter output is connected to a low noise amplifier 12 that in turn is connected to an image filter 13 . The image filter 13 output is fed to a mixer 14 which has a second input connected to a local oscillator (LO) signal 15 . The output of the mixer 14 is provided to an intermediate frequency (IF) filter 16 . The output of the IF filter is used in the communications system in a way that is well known. This architecture is capable of providing high reliability and stable performance in mobile communications. In super-heterodyne receivers, the image frequency presents a problem because the image frequency is superimposed on the desired signal. In order to solve this problem and provide removal, or rejection, of the image frequency signal, the super-heterodyne receiver front-end can consist of any of several topologies. Especially useful approaches are the use of an image rejection filter component in a Hartley architecture or a Weaver architecture. Modem radio frequency receivers are often provided on a semiconductor chip to provide the advantages of lower cost, greater compactness and reduced power consumption. The chip is indicated in FIG. 1 by the solid line 18 enclosing the low noise amplifier 12 , local oscillator 15 , mixer 14 and IF filter 16 . Currently, most of the commercially available radio frequency receivers use off-chip passive bandpass filters, such as ceramic or surface acoustic wave (SAW) filters, because the off-chip filters provide the most robust solution to the image rejection problem. As has been well known for years, surface acoustic wave bandpass filters have a number of advantages, for example, no power consumption, no linearity degradation, and extraordinarily high quality factor. However, the high cost and large size of such separate bandpass filters make these filters less attractive for use in the next generation receivers. The conventional receiver system of FIG. 1 uses an external filter for image rejection. Specifically, the RF filter 11 and image filter 13 are provided as external components to the chip 18 . The current, off-chip passive filters, such as surface acoustic wave filters or ceramic filters, are used for image frequency rejection, but these bulky filters are the major impediment to raising the level of integration of the radio frequency circuit since they cannot be easily integrated. Systems using these filters have a relatively high cost and large size. Therefore, to decrease the circuit size, monolithic integration of the filter with the other electrical devices of the receiver circuit is being researched. In applications for use at frequencies below 3 GHz, monolithic circuits are provided using an image rejection mixer for phase cancellation to satisfy an image rejection specification of better than 41 dB. Practical systems require higher values of image rejection. As such, it would be desirable to combine an on-chip image filter with an integrated image reject mixer to obtain a very high on-chip image rejection. When a wide range of signal powers is received by an antenna in a wireless communications system, the system requires the addition of a variable gain stage. The variable gain function is generally provided in later stages in the radio receiver system. For example, in FIG. 2 is provided a variable gain amplifier 17 at the output of the IF filter 16 . The variable gain amplifier includes a control lead 18 , as is well known, for controlling the output gain of the variable gain stage to compensate for changes in the power of the received signal. If the variable gain function is provided at the early stages in the system such as using a low noise amplifier (LNA) 12 a such as shown in FIG. 2 , then the gain variation is being made in the presence of minimum power signals and the signal-to-noise ratio increases. If instead the gain control is provided later in the receiver system while in the presence of maximum power signals, the last stage of the receiver is not saturated. Furthermore, with such gain controllable low noise amplifiers (LNA), the target dynamic range of the VGA (Variable Gain Amplifier) 20 tends to be degraded. A low noise amplifier (LNA) is used in the RF receiver in a wireless communication application to obtain the necessary power gain and decreasing the noise factor (NF). Conventional low noise amplifiers have high power consumption at radio frequencies to satisfy the required power gain and to provide the characteristics necessary in an RF receiver application. The conventional LNA uses a one unit common source amplifier structure as shown in FIG. 3 configured as a cascode amplifier. In particular, the amplifier circuit of FIG. 3 includes a first FET 45 connected with a gate inductor 46 at its gate lead, through which is fed the input signal of the amplifier circuit. The source of the FET 45 is connected through a source inductor 47 to ground. The drain of the FET 45 is connected to a source of a second FET 43 at a node 44 . The drain of the second FET 43 is connected through a drain inductor 41 to the supply voltage VDD. A bias voltage V bias is connected at the gate of the second FET 43 . A capacitor 42 is connected to the drain of the second FET 43 as well to provide the output signal for the amplifier through the capacitor. Operationally, in FIG. 3 in order to achieve low noise and to provide power matching at the same time, the source inductor 47 , also denoted Ls in the drawing, is used. When an inductor having a high quality factor is used for this source degeneration function, the result is that the amplifier has good noise performance. The bonding wire to the chip has been used as the inductor for source degeneration, and its length is selected by considering a minimum size at for the chip layout and for bonding. The drain inductor 41 , also denoted Ld, the source inductor 47 and the gate inductor 46 , also denoted Lg in the drawing, as well as the capacitor 42 , also denoted C 1 , are external elements. The gate inductor 46 and the source inductor 47 are used for matching input impedance, and the drain inductor 41 and capacitor 42 are used for matching output impedance. The bias signal V bias is supplied to the gate of the transistor 43 , also denoted M 2 on the drawing. The elements within the dashed line are on the chip. In this structure, the signal is amplified by the gain of the cascode structure of the two transistors 45 and 43 . Amplifiers of this type are used in wireless communications. Wireless communications systems have exhibited remarkable growth over the past decade. Wireless voice and data applications are being enabled by rapidly emerging wireless technologies, such as cellular telephony, personal communications systems and wireless local area network (WLANs), to name a few. Digital modulation techniques, miniaturization of transceivers due to advances in monolithic integrated circuit design and the development of high frequency, microwave and millimeter wave RF systems in both the licensed and unlicensed bands have all contributed to improving the quality and bandwidth capacity of these systems and to reducing the size and costs of the components. The LNA (Low Noise Amplifier) is a critical front end component of a wireless receiver. As noted above, its function is to take the relatively weak signal received at the antenna and, after filtering of the signal, amplify it with maximum power transfer and with a minimum of added noise for further processing (referred to as down conversion, etc.). The maximum power transfer is achieved by designing the LNA to have an input impedance that matches a characteristic input impedance of the antenna, which is commonly 50 ohms. Thus, a true concurrent LNA, as a critical front end component of a concurrent receiver, must be capable of (1) matching the characteristic input impedance of the received signal at the antenna at the respective frequency band; (2) simultaneously amplifying the received signal(s); and (3) accomplishing the above with minimum added electrical noise. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides a LNA (Low Noise Amplifier) for use at radio frequencies in a wireless communication system, the amplifier preferably being used in an early stage of the wireless receiver and having a low noise characteristic. In one embodiment, the amplifier has a cascode configuration and includes an added inductor at a node between the two active elements to cancel parasitic capacitance and thereby cancel high frequency leakage. Further embodiments utilize the added inductor as part of a filter section to provide filtering of the image frequency from the radio signal. The previously mentioned inductor functions in combination with an added capacitor to provide this image rejection. In yet further embodiments, the present low noise amplifier includes an added gain controller to simultaneously provide, in a preferred embodiment, image rejection and gain control functions in a low noise amplifier. The gain controller is provided by an active element, such as a FET (Field Effect Transistor) at the gate of which is connected a control signal. An added benefit of the preferred embodiment is that noise contributions are reduced compared to the core LNA cascode amplifier device. In addition, the gain control improves the input linearity of front-end circuit in the presence of large signals. The present low noise amplifier is used for wireless communications systems, including wireless communications at 915 MHz according to the Zigbee (section 802.15.4) standard as well as for wireless communications systems using Wi-Fi or Bluetooth (section 802.11 a, b and g) standards, GSM systems, CDMA, TDMA, packet data systems, etc. | 20040407 | 20070904 | 20051013 | 96852.0 | 0 | JACKSON, BLANE J | LOW NOISE AMPLIFIER FOR WIRELESS COMMUNICATIONS | SMALL | 0 | ACCEPTED | 2,004 |
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10,819,526 | ACCEPTED | Cable anchor bracket | According to one embodiment, a cable anchor system for an end terminal includes a cable anchor bracket configured to couple to a guardrail, in which the cable anchor bracket includes a flat plate having an aperture formed therein and a plurality of protrusions extending from a plane containing the aperture. The protrusions are configured to releasably engage the guardrail. | 1. A guardrail system, comprising: a guardrail; an end terminal coupled to the guardrail; a support post for supporting the end terminal; a cable anchor bracket coupled to the guardrail; a cable extending between the support post and the cable anchor bracket; the cable anchor bracket comprising: a plate having an aperture formed therein; a plurality of protrusions coupled to the plate, the plurality of protrusions releasably engaging a plurality of apertures formed in the guardrail; and wherein the cable is coupled to the support post at a first end and coupled to the aperture of the plate at a second end, the cable terminating at the aperture such that an extension of a longitudinal axis of the cable from the second end forms an acute angle with respect to a longitudinal axis of the guardrail and approximately intersects a centroid of the protrusions. 2. The guardrail system of claim 1, further comprising a shackle coupling the second end of the cable to the aperture. 3. The guardrail system of claim 1, wherein the longitudinal axis of the cable substantially aligns with a plane containing the plate. 4. The guardrail system of claim 1, wherein the acute angle is between approximately 15 and 25 degrees. 5. The guardrail system of claim 1, wherein the aperture is located below a horizontal line extending through each of the protrusions. 6. The guardrail system of claim 1, wherein a thickness of the plate is between approximately 1/4 inches and 3/4 inches. 7. The guardrail system of claim 1, wherein the plate comprises a single flat plate. 8. The guardrail system of claim 1, wherein the end terminal comprises a guardrail extruder terminal. 9. A cable anchor system for an end terminal, comprising: a cable anchor bracket configured to couple to a guardrail, the cable anchor bracket comprising: a flat plate having an aperture formed therein; and a plurality of protrusions extending from a plane containing the aperture, the protrusions configured to releasably engage the guardrail. 10. The cable anchor system of claim 9, further comprising a cable having a first end configured to couple to a support post of the end terminal and a second end configured to couple to the aperture such that an extension of a longitudinal axis of the cable forms an acute angle with respect to a longitudinal axis of the guardrail and intersects a line extending through interior ones of the protrusions when the cable is coupled to the aperture. 11. The cable anchor system of claim 10, further comprising a shackle configured to couple the cable to the aperture. 12. The cable anchor system of claim 10, wherein the longitudinal axis of the cable substantially aligns with a plane containing the flat plate. 13. The cable anchor system of claim 10, wherein the acute angle is between approximately 15 and 25 degrees. 14. The cable anchor system of claim 9, wherein the protrusions are aligned in a single row and the aperture is located below a horizontal line extending through the protrusions. 15. The cable anchor system of claim 9, wherein a thickness of the flat plate is between approximately 1/4 inches and 3/4 inches. 16. A guardrail system, comprising: a guardrail; an end terminal coupled to the guardrail; a support post for supporting the end terminal; a cable anchor bracket coupled to an attachment portion of the guardrail; a cable extending between the support post and the cable anchor bracket; the cable anchor bracket comprising: a flat plate having an aperture formed therein; a plurality of protrusions coupled to the flat plate, the plurality of protrusions releasably engaging a plurality of apertures formed in the attachment portion of the guardrail; and wherein the cable is coupled to the support post at a first end and coupled to the aperture of the flat plate at a second end, a longitudinal axis of the cable substantially aligning with a plane containing the flat plate. 17. The guardrail system of claim 16, wherein a distance between the plane containing the flat plate and the attachment portion of the guardrail is no more than approximately 3/4 inches. 18. The guardrail system of claim 16, wherein the second end of the cable terminates at the aperture such that an extension of the longitudinal axis of the cable from the second end forms an acute angle with respect to a longitudinal axis of the guardrail and approximately intersects a centroid of the protrusions. 19. The guardrail system of claim 18, wherein the acute angle is between approximately 15 and 25 degrees. 20. The guardrail system of claim 16, further comprising a shackle coupling the second end of the cable to the aperture. 21. The guardrail system of claim 16, wherein the protrusions are aligned in a single row and the aperture is located below a horizontal line extending through the protrusions. 22. The guardrail system of claim 16, wherein a thickness of the plate is between approximately 1/4 inches and 3/4 inches. 23. The guardrail system of claim 16, wherein the end terminal comprises a guardrail extruder terminal. 24. A cable anchor system for an end terminal, comprising: a cable anchor bracket configured to couple to an attachment portion of a guardrail, the cable anchor bracket comprising: a flat plate having an aperture formed therein; a plurality of protrusions coupled to the flat plate for releasably engaging the guardrail; and wherein the aperture is configured to couple a cable thereto such that a longitudinal axis of the aperture is substantially perpendicular to a longitudinal axis of the cable and the longitudinal axis of the cable substantially aligns with a plane containing the flat plate. 25. The cable anchor system of claim 24, further comprising the cable having a first end configured to couple to a support post of the end terminal and a second end configured to couple to the aperture. 26. The cable anchor system of claim 25, further comprising a shackle configured to couple the second end of the cable to the aperture. 27. The cable anchor system of claim 25, wherein the cable is configured to couple to a portion of the flat plate at a location below a horizontal line extending through each of the protrusions. 28. The cable anchor system of claim 24, wherein a distance between the plane containing the flat plate and the attachment portion of the guardrail is no more than approximately 3/4 inches. 29. The cable anchor system of claim 24, wherein an extension of a longitudinal axis of the cable forms an acute angle with respect to a horizontal plane and approximately intersects a line extending through interior ones of the protrusions when the cable is coupled to the aperture. 30. The cable anchor system of claim 29, wherein the acute angle is between approximately 15 and 25 degrees. 31. The cable anchor system of claim 24, wherein a thickness of the flat plate is between approximately 1/4 inches and 3/4 inches. 32. A guardrail system, comprising: a box beam; an end terminal coupled to the box beam; a support post for supporting the end terminal; a cable anchor bracket coupled to the box beam; a cable extending between the support post and the cable anchor bracket; the cable anchor bracket comprising: a flange plate; a plurality of protrusions coupled to the flange plate, the plurality of protrusions releasably engaging a plurality of apertures formed in the box beam; and a web plate coupled to the flange plate and having an aperture formed therein; and wherein the cable is coupled to the support post at a first end and coupled to the aperture of the web plate at a second end, the cable terminating at the aperture such that an extension of a longitudinal axis of the cable from the second end forms an acute angle with respect to a longitudinal axis of the box beam and approximately intersects a centroid of the protrusions. 33. The guardrail system of claim 32, further comprising a shackle coupling the second end of the cable to the aperture. 34. The guardrail system of claim 32, wherein the longitudinal axis of the cable substantially aligns with a plane containing the web plate. 35. The guardrail system of claim 32, wherein the acute angle is between approximately 15 and 25 degrees. 36. The guardrail system of claim 32, wherein a thickness of each of the flange and web plates is between approximately 1/4 inches and 3/4 inches. 37. The guardrail system of claim 32, wherein the end terminal comprises a box beam terminal. 38. A cable anchor system for an end terminal, comprising: a cable anchor bracket configured to couple to a bottom of a box beam, the cable anchor bracket comprising: a flange plate; a plurality of protrusions coupled to the flange plate, the plurality of protrusions releasably engaging a plurality of apertures formed in the bottom of the box beam; and a web plate coupled to and extending substantially perpendicular to the flange plate, the web plate having an aperture formed therein. 39. The cable anchor system of claim 38, further comprising a cable having a first end configured to couple to a support post of the end terminal and a second end configured to couple to the aperture such that an extension of a longitudinal axis of the cable forms an acute angle with respect to a longitudinal axis of the box beam and intersects a line extending through interior ones of the protrusions when the cable is coupled to the aperture. 40. The cable anchor system of claim 39, further comprising a shackle configured to couple the cable to the aperture. 41. The cable anchor system of claim 39, wherein the longitudinal axis of the cable substantially aligns with a plane containing the web plate. 42. The cable anchor system of claim 39, wherein the acute angle is between approximately 15 and 25 degrees. 43. The cable anchor system of claim 38, wherein a thickness of each of the flange and web plates is between approximately 1/4 inches and 3/4 inches. | BACKGROUND OF THE INVENTION Guardrail systems are widely used along heavily traveled roadways to enhance the safety of the roadway and adjacent roadside. For example, end terminals are utilized at the upstream end of guardrail systems to dissipate impact energy from head-on collisions of vehicles with the upstream end to prevent intense deceleration of the vehicles. In addition, guardrail systems are designed to contain and redirect vehicles that impact the guardrails predominantly from the side. One element that is utilized in guardrail systems to address impacts along the side of the guardrail downstream from the end terminal is a tension cable that connects between the end terminal support post and the guardrail. The tension cable is designed to provide tension strength during side impacts and to breakaway during head-on impacts to avoid counteracting the benefits of the impact absorbing end terminal. SUMMARY OF THE INVENTION According to one embodiment, a cable anchor system for an end terminal includes a cable anchor bracket configured to couple to a guardrail, in which the cable anchor bracket includes a flat plate having an aperture formed therein and a plurality of protrusions extending from a plane containing the aperture. The protrusions are configured to releasably engage the guardrail. Technical advantages of particular embodiments of the present invention include improved performance of the connection between the tension cable and the guardrail by improving the alignment between the tension cable and anchor bracket. This is facilitated by an improved cable anchor bracket that reduces the eccentricity of the alignment between the cable and the guardrail. The cable anchor bracket also reduces manufacturing cost. Other technical advantages are readily apparent to one skilled in the art from the following figures, descriptions and claims. Moreover, while specific advantages have been enumerated above, various embodiments may include all, some or none of the enumerated advantages. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are plan and elevation views, respectively, of a guardrail system according to one embodiment of the present invention; FIGS. 3A and 3B are perspective and elevation views, respectively, illustrating the coupling of a cable anchor bracket to a guardrail in accordance with one embodiment of the present invention; FIG. 4 is an elevation view of a cable anchor bracket according to one embodiment of the present invention; FIG. 5 is an elevation view of a guardrail system according to one embodiment of the present invention in which the guardrail is a box beam; and FIGS. 6A and 6B are perspective and elevation views, respectively, illustrating the coupling of a cable anchor bracket to a box beam in accordance with one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION FIGS. 1 and 2 are plan and elevation views, respectively, of a guardrail system 100 according to one embodiment of the present invention. Guardrail system 100 may be installed adjacent a roadway to protect vehicles, drivers and passengers from various obstacles and hazards and prevent vehicles from leaving the roadway during a traffic accident or other hazardous condition. Guardrail systems incorporating aspects of the present invention may be used in median strips or shoulders of highways, roadways, or any suitable path that is likely to encounter vehicular traffic. In the illustrated embodiment, guardrail system 100 includes a guardrail 102, an end terminal 104, a support post 106, a cable anchor bracket 108, and a cable 110. Guardrail 102 may be any suitable guardrail, such as a w-beam (illustrated in FIGS. 1 and 2) or a box beam (as illustrated in FIG. 5), having any suitable length. In the embodiment illustrated in FIGS. 1 and 2, an end of guardrail 102 is supported by end terminal 104, which may be any suitable end treatment. In the illustrated embodiment, end terminal 104 resembles a guardrail extruder terminal (“GET”), such as the ET-2000® and ET-PLUS® manufactured by Trinity Industries, Inc. An example description of a GET is described in U.S. Pat. No. 4,928,928 by Buth et al., which is herein incorporated by reference. The present invention contemplates any suitable end terminal that has a releasable anchor plate, such as a Sequential Kinking Guardrail Terminal System (“SKGTS”), an Anchor Assembly for Highway Guardrail End Terminal (“AAHGET”), a Guardrail Cutting Terminal (“GCT”), and a Box Beam Terminal. Support post 106 functions to support end terminal 104 and/or guardrail 102. In the illustrated embodiment, support post 106 is a breakaway support post formed from a generally rectangular wood post; however, support post 106 may be any suitable support post formed from any suitable material and having any suitable shape. Cable anchor bracket 108 may be coupled to guardrail 102 in any suitable manner; however, it is envisioned that cable anchor bracket 108 be releasably engaged with guardrail 102 so that cable anchor bracket 108 may be easily released from guardrail 102 during a head-on collision of a vehicle with an end 105 of end terminal 104 to avoid possible jamming of the movement of end terminal 104 and facilitate the safe and effective kinetic energy reduction during the head-on collision. In the illustrated embodiment, cable anchor bracket 108 is releasably coupled to guardrail 102 with a plurality of protrusions 112, as described in greater detail below in conjunction with FIGS. 3A and 3B. According to the teachings of the present invention, cable anchor bracket 108 provides an improved alignment of cable 110 with guardrail 102 to provide improved performance of the connection between cable 110 and guardrail 102. As described in greater detail below, eccentricities with respect to cable 110 and the connection between cable anchor bracket 108 and guardrail 102 are reduced, thereby reducing moments resulting from a collision of a vehicle with the side of guardrail 102. A reduction in moments reduces the likelihood of “tear-out” of protrusions 112 and strengthens the connection between cable anchor bracket 108 and guardrail 102. The connection between cable anchor bracket 108 and guardrail 102 is described in greater detail below in conjunction with FIGS. 3A and 3B. Cable 110 extends between support post 106 and cable anchor bracket 108. Cable 110 may be any suitable elongated element formed from any suitable material that provides tension to guardrail system 100 during a collision of a vehicle with a side of guardrail 102. A general function of cable 110 during a collision may be found in U.S. Pat. No. 4,928,928. In the illustrated embodiment, cable 110 forms an acute angle 111 with respect to a longitudinal axis 109 of guardrail 102. Acute angle 111 may be any suitable angle; however, in one embodiment, acute angle 111 is between approximately 15 and 25 degrees. One end of cable 110 couples to a lower portion of support post 106 in any suitable manner and the other end of cable 110 couples to cable anchor bracket 108 in any suitable manner. One example of coupling cable 110 to cable anchor bracket 108 is shown and described below in conjunction with FIGS. 3A and 3B. FIG. 3A is a perspective view and FIG. 3B is an elevation view illustrating the coupling of cable 110 to cable anchor bracket 108 and cable anchor bracket 108 to guardrail 102 according to one embodiment of the invention. In the illustrated embodiment, cable anchor bracket 108 is formed from a plate 113 having an aperture 119 formed therein and a plurality of protrusions 112 coupled to plate 113 and extending from a plane containing aperture 119. Plate 113 is preferably a single flat plate of structural steel with a thickness between approximately 1/4 inches and 3/4 inches. However, plate 113 may be formed from any suitable material having any suitable thickness. Aperture 119 is utilized to couple cable 110 to cable anchor bracket 108 by any suitable method. In the illustrated embodiment, a shackle 116 is utilized along with a bolt 117 and a nut 118 to couple the end of cable 110 to plate 113. The use of shackle 116 allows a longitudinal axis 120 (FIG. 3B) of cable 110 to substantially align with a plane containing plate 113. For example, a plane running through the mid-thickness of plate 113, as denoted by reference number 122, substantially aligns with longitudinal axis 120. Depending on the location of support post 106 (see FIG. 1) and where cable 110 couples to support post 106, longitudinal axis 120 may form a slight angle with a plane containing plate 113. In addition, a longitudinal axis 121 of aperture 119 (FIG. 3B) is substantially perpendicular to longitudinal axis 120. This positioning of cable 110 with respect to plate 113 results in an eccentricity 123 with guardrail 102 that is less than eccentricities of prior cable anchor systems. The reduction in eccentricity reduces the moment on the connection of protrusions 112 with guardrail 102, thereby introducing less stress to the connection during a side impact collision. Thus, there is less chance for “tearing-out” of protrusions 112 during a side impact collision, which improves the performance of the connection. In the illustrated embodiment, protrusions 112 cooperate with a plurality of apertures 114 formed in guardrail 102 in order to releasably couple cable anchor bracket 108 to guardrail 102. In the illustrated embodiment, this is facilitated by a plurality of tabs 115 associated with respective protrusions 112 that “hook on” respective apertures 114 formed in an attachment portion 129 of guardrail 102. The tautness of cable 110 after installation ensures the correct positioning of cable anchor bracket 108 in addition to keeping a snug fit of protrusions 112 with apertures 114. Any suitable number and arrangement of protrusions 112 may be utilized within the teachings of the present invention. The present invention also contemplates other suitable coupling methods for cable anchor bracket 108 that facilitate a releasable engagement. FIG. 4 is an elevation view illustrating another advantage of cable anchor bracket 108 according to one embodiment of the invention. As described above in conjunction with FIGS. 1 and 2, cable 110 forms acute angle 111 with respect to the longitudinal axis 109 of guardrail 102. As illustrated by FIG. 4, this facilitates an extension 122 of longitudinal axis 120 of cable 110 intersecting a line 130 extending through the interior protrusions, as denoted by reference numeral 132, when viewed from a side elevation as in FIG. 4. In a particular embodiment, extension 122 may intersect a centroid 124 of all of the protrusions 112. Interior protrusions are defined by all of the protrusions 112 except the upstream-most protrusion(s) 112 and downstream-most protrusion(s) 112. This positioning of cable 110 with respect to plate 113 substantially reduces or eliminates eccentricities, as denoted by eccentricity 126, that exists in prior cable anchor systems, thereby reducing an additional moment on the connection between cable anchor bracket 108 and guardrail 102. Eccentricity 126 results from the positioning of prior cables (denoted by reference numeral 127) of prior cable anchor systems. Eccentricity 126 causes additional stress on the connection between the cable anchor bracket and the guardrail of prior guardrail systems, thereby enhancing the possibility of failure of the connection and minimizing the effectiveness of a tension cable during a side impact with the guardrail. Referring now to FIG. 5, an elevation view of guardrail system 100 according to another embodiment of the present invention is illustrated in which the guardrail is a box beam 500. In this embodiment, guardrail system 100 includes a cable anchor bracket 502 that couples to a bottom 503 of box beam 500. In the illustrated embodiment, box beam 500 has an “open” cross-section that resembles a C-section; however, box beam 500 may also have a “closed” cross-section. Cable anchor bracket 502 may be coupled to bottom 503 of box beam 500 in any suitable manner; however, it is envisioned that cable anchor bracket 502 be releasably engaged with box beam 500 for reasons discussed above in conjunction with cable anchor bracket 108. In the illustrated embodiment, cable anchor bracket 502 is releasably coupled to box beam 500 with a plurality of protrusions 504, as described in greater detail below in conjunction with FIGS. 6A and 6B. FIG. 6A is a perspective view and FIG. 6B is an elevation view illustrating the coupling of a cable 506 to cable anchor bracket 502 and cable anchor bracket 502 to box beam 500 according to one embodiment of the invention. In the illustrated embodiment, cable anchor bracket 502 is formed from a flange plate 508, a web plate 510 having an aperture 512 formed therein, and a plurality of protrusions 504 coupled to flange plate 508. Flange plate 508 and web plate 510 are preferably single flat plates of structural steel with a thickness between approximately 1/4 inches and 3/4 inches. However, flange plate 508 and web plate 510 may be formed from any suitable material having any suitable thickness. In the illustrated embodiment, web plate 510 extends substantially perpendicular to flange plate 508; however, web plate 510 may be angled with respect to flange plate 508 in some embodiments. Aperture 512 is utilized to couple cable 506 to cable anchor bracket 502 by any suitable method. In the illustrated embodiment, a shackle 511 is utilized along with a bolt 513 and a nut 515 to couple the end of cable 506 to web plate 510. The use of shackle 511 allows a longitudinal axis 516 (FIG. 6B) of cable 506 to substantially align with web plate 510. Depending on the location of support post 106 (see FIG. 1) and where cable 506 couples to support post 106, longitudinal axis 516 may form a slight angle with web plate 510. In the illustrated embodiment, protrusions 504 cooperate with a plurality of apertures 518 formed in bottom 503 of box beam 500 in order to releasably couple cable anchor bracket 502 to box beam 500. In the illustrated embodiment, this is facilitated by a plurality of tabs 509 associated with respective protrusions 504 that “hook on” respective apertures 518 formed in bottom 503 of box beam 500. The tautness of cable 506 after installation ensures the correct positioning of cable anchor bracket 502 in addition to keeping a snug fit of protrusions 504 with apertures 518. Any suitable number and arrangement of protrusions 504 may be utilized within the teachings of the present invention. The present invention also contemplates other suitable coupling methods for cable anchor bracket 502 that facilitate a releasable engagement. Referring back to FIG. 5, cable 506 forms an acute angle 507 with respect to the longitudinal axis of box beam 500. This facilitates an extension 520 of longitudinal axis 516 of cable 506 intersecting a line extending through the interior protrusions, as denoted by reference numeral 522. In a particular embodiment, extension 520 may intersect a centroid of all of the protrusions 504. Thus, an improved cable anchor bracket is disclosed by the present invention that improves performance of the connection of the cable anchor bracket with the guardrail by reducing eccentricities associated therewith. Reduced eccentricities result in reduced moments and reduced stress at the connection, thereby increasing the strength of the connection and ensuring that the anchor cable may perform its function in an efficient and safe manner. Although the present invention is described by several embodiments, various changes and modifications may be suggested to one skilled in the art. The present invention intends to encompass such changes and modifications as they fall within the scope of the present appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>Guardrail systems are widely used along heavily traveled roadways to enhance the safety of the roadway and adjacent roadside. For example, end terminals are utilized at the upstream end of guardrail systems to dissipate impact energy from head-on collisions of vehicles with the upstream end to prevent intense deceleration of the vehicles. In addition, guardrail systems are designed to contain and redirect vehicles that impact the guardrails predominantly from the side. One element that is utilized in guardrail systems to address impacts along the side of the guardrail downstream from the end terminal is a tension cable that connects between the end terminal support post and the guardrail. The tension cable is designed to provide tension strength during side impacts and to breakaway during head-on impacts to avoid counteracting the benefits of the impact absorbing end terminal. | <SOH> SUMMARY OF THE INVENTION <EOH>According to one embodiment, a cable anchor system for an end terminal includes a cable anchor bracket configured to couple to a guardrail, in which the cable anchor bracket includes a flat plate having an aperture formed therein and a plurality of protrusions extending from a plane containing the aperture. The protrusions are configured to releasably engage the guardrail. Technical advantages of particular embodiments of the present invention include improved performance of the connection between the tension cable and the guardrail by improving the alignment between the tension cable and anchor bracket. This is facilitated by an improved cable anchor bracket that reduces the eccentricity of the alignment between the cable and the guardrail. The cable anchor bracket also reduces manufacturing cost. Other technical advantages are readily apparent to one skilled in the art from the following figures, descriptions and claims. Moreover, while specific advantages have been enumerated above, various embodiments may include all, some or none of the enumerated advantages. | 20040407 | 20070717 | 20051013 | 90294.0 | 0 | FERGUSON, MICHAEL P | CABLE ANCHOR BRACKET | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,820,240 | ACCEPTED | Retinal prosthesis with side mounted inductive coil | The invention is a retinal prosthesis with an inductive coil mounted to the side of the eye by means of a strap around the eye. This allows for close coupling to an external coil and movement of the entire implanted portion with movement of the eye ball. | 1. A retinal prosthesis comprising: An electrode array suitable to be mounted in close proximity to a retina; An electronics package; An electrical cable coupling said electrode array to said electronics package; and A secondary inductive coil, electrically coupled to said electronics package and suitable to be mounted to the side of a sclera. 2. The retinal prosthesis according to claim 1, further comprising a strap connected to said secondary inductive coil and surrounding the sclera. 3. The retinal prosthesis according to claim 1, further comprising a strap connected to said electronics package and surrounding the sclera. 4. The retinal prosthesis according to claim 1, further comprising suture tabs connected to said secondary inductive coil suitable for attaching said secondary inductive coil to a sclera. 5. The retinal prosthesis according to claim 1, further comprising suture tabs connected to said electronics package suitable for attaching said electronics package to a sclera. 6. The retinal prosthesis according to claim 2, further comprising a fan tail connected to said secondary inductive coil and to said strap. 7. The retinal prosthesis according to claim 2, further comprising a hook on said prosthesis suitable for engaging a surgical tool. 8. The retinal prosthesis according to claim 2, further comprising a sleeve for attaching ends of said strap together. 9. The retinal prosthesis according to claim 1, wherein said cable and electrode array comprise metal traces sandwiched between thin polymer films. 10. The retinal prosthesis according to claim 9, wherein said cable is folded to present the same side of said cable to both said electronics package and the retina. 11. The retinal prosthesis according to claim 1, wherein said electrical cable is suitable to pierce the sclera. 12. The retinal prosthesis according to claim 1, wherein said electrical cable is suitable to pierce pars plana region of the sclera. 13. The retinal prosthesis according to claim 1, wherein said electrode array is suitable to placed in an epiretinal location. 14. The retinal prosthesis according to claim 1, wherein said secondary inductive coil is a wound wire coil. 15. The retinal prosthesis according to claim 2, further comprising a fan tail connected to said electronics package to said cable to facilitate passing said cable through the sclera. 16. The retinal prosthesis according to claim 1, wherein said secondary inductive coil is substantially oval shaped. 17. The retinal prosthesis according to 1, further comprising: A first passive coil suitable be mounted within the body on the side of a skull; and A second passive coil electrically coupled to said first passive coil and suitable to be mounted within the body proximate to said secondary inductive coil. 18. A retinal prosthesis comprising a video capture device; a source of power; a primary inductive coil suitable to be placed outside of the body and electrically coupled to at least one of said video capture device and said source of power; An electrode array suitable to be mounted in close proximity to a retina; An electronics package; An electrical cable coupling said electrode array to said electronics package; and A secondary inductive coil, electrically coupled to said electronics package and suitable to be mounted to the side of a sclera and in close proximity to said primary inductive coil. 19. The retinal prosthesis according to claim 18, further comprising a strap connected to said secondary inductive coil and surrounding the sclera. 20. The retinal prosthesis according to claim 18, further comprising a strap connected to said electronics package and surrounding the sclera. 21. The retinal prosthesis according to claim 18, further comprising suture tabs connected to said secondary inductive coil suitable for attaching said secondary inductive coil to a sclera. 22. The retinal prosthesis according to claim 19, further comprising suture tabs connected to said electronics package suitable for attaching said electronics package to a sclera. 23. The retinal prosthesis according to claim 19, further comprising a fan tail connected to said secondary inductive coil and to said strap suitable to facilitate to passing said strap and said secondary inductive coil through muscle tissue. 24. The retinal prosthesis according to claim 19, further comprising a hook on said prosthesis suitable for engaging a surgical tool. 25. The retinal prosthesis according to claim 19, further comprising a sleeve for attaching ends of said strap together. 26. The retinal prosthesis according to claim 19, wherein said cable and electrode array comprise metal traces sandwiched between thin polymer films. 27. The retinal prosthesis according to claim 26, wherein said cable is folded to present the same side of said cable to both said electronics package and the retina. 28. The retinal prosthesis according to claim 18, wherein said primary coil is substantially oval shaped. 29. The retinal prosthesis according to claim 18, wherein said electrical cable is suitable to pierce the sclera. 30. The retinal prosthesis according to claim 18, wherein said electrical cable is suitable to pierce pars plana region of the sclera. 31. The retinal prosthesis according to claim 18, wherein said electrode array is suitable to placed in an epiretinal location. 32. The retinal prosthesis according to claim 18, wherein said secondary inductive coil is a wound wire coil. 33. The retinal prosthesis according to claim 18, wherein said primary coil is integrated in the temple of a pair of glasses. 34. The retinal prosthesis according to 18, further comprising: A first passive coil suitable be mounted within the body and proximate to said primary inductive coil; and A second passive coil electrically coupled to said first passive coil and suitable to be mounted within the body proximate to said secondary inductive coil. 35. A retinal prosthesis comprising: An electrode array suitable to be mounted in close proximity to a retina; An electronics package; An electrical cable coupling said electrode array to said electronics package; and A secondary inductive coil, electrically coupled to said electronics package and suitable to be mounted to the side of a skull. | GOVERNMENT RIGHTS NOTICE This invention was made with government support under grant No. R24EY12893-01, awarded by the National Institutes of Health. The government has certain rights in the invention. FIELD OF THE INVENTION The present invention is generally directed to a visual prosthesis and more specifically to an improved mechanical and electrical configuration for retinal prosthesis for artificial vision. BACKGROUND OF THE INVENTION In 1755 LeRoy passed the discharge of a Leyden jar through the orbit of a man who was blind from cataract and the patient saw “flames passing rapidly downwards.” Ever since, there has been a fascination with electrically elicited visual perception. The general concept of electrical stimulation of retinal cells to produce these flashes of light or phosphenes has been known for quite some time. Based on these general principles, some early attempts at devising a prosthesis for aiding the visually impaired have included attaching electrodes to the head or eyelids of patients. While some of these early attempts met with some limited success, these early prosthetic devices were large, bulky and could not produce adequate simulated vision to truly aid the visually impaired. In the early 1930's, Foerster investigated the effect of electrically stimulating the exposed occipital pole of one cerebral hemisphere. He found that, when a point at the extreme occipital pole was stimulated, the patient perceived a small spot of light directly in front and motionless (a phosphene). Subsequently, Brindley and Lewin (1968) thoroughly studied electrical stimulation of the human occipital (visual) cortex. By varying the stimulation parameters, these investigators described in detail the location of the phosphenes produced relative to the specific region of the occipital cortex stimulated. These experiments demonstrated: (1) the consistent shape and position of phosphenes; (2) that increased stimulation pulse duration made phosphenes brighter; and (3) that there was no detectable interaction between neighboring electrodes which were as close as 2.4 mm apart. As intraocular surgical techniques have advanced, it has become possible to apply stimulation on small groups and even on individual retinal cells to generate focused phosphenes through devices implanted within the eye itself. This has sparked renewed interest in developing methods and apparati to aid the visually impaired. Specifically, great effort has been expended in the area of intraocular retinal prosthesis devices in an effort to restore vision in cases where blindness is caused by photoreceptor degenerative retinal diseases such as retinitis pigmentosa and age related macular degeneration which affect millions of people worldwide. Neural tissue can be artificially stimulated and activated by prosthetic devices that pass pulses of electrical current through electrodes on such a device. The passage of current causes changes in electrical potentials across visual neuronal membranes, which can initiate visual neuron action potentials, which are the means of information transfer in the nervous system. Based on this mechanism, it is possible to input information into the nervous system by coding the information as a sequence of electrical pulses which are relayed to the nervous system via the prosthetic device. In this way, it is possible to provide artificial sensations including vision. One typical application of neural tissue stimulation is in the rehabilitation of the blind. Some forms of blindness involve selective loss of the light sensitive transducers of the retina. Other retinal neurons remain viable, however, and may be activated in the manner described above by placement of a prosthetic electrode device on the inner (toward the vitreous) retinal surface (epiretinal). This placement must be mechanically stable, minimize the distance between the device electrodes and the visual neurons, and avoid undue compression of the visual neurons. In 1986, Bullara (U.S. Pat. No. 4,573,481) patented an electrode assembly for surgical implantation on a nerve. The matrix was silicone with embedded iridium electrodes. The assembly fit around a nerve to stimulate it. Dawson and Radtke stimulated cat's retina by direct electrical stimulation of the retinal ganglion cell layer. These experimenters placed nine and then fourteen electrodes upon the inner retinal layer (i.e., primarily the ganglion cell layer) of two cats. Their experiments suggested that electrical stimulation of the retina with 30 to 100 uA current resulted in visual cortical responses. These experiments were carried out with needle-shaped electrodes that penetrated the surface of the retina (see also U.S. Pat. No. 4,628,933 to Michelson). The Michelson '933 apparatus includes an array of photosensitive devices on its surface that are connected to a plurality of electrodes positioned on the opposite surface of the device to stimulate the retina. These electrodes are disposed to form an array similar to a “bed of nails” having conductors which impinge directly on the retina to stimulate the retinal cells. U.S. Pat. No. 4,837,049 to Byers describes spike electrodes for neural stimulation. Each spike electrode pierces neural tissue for better electrical contact. U.S. Pat. No. 5,215,088 to Norman describes an array of spike electrodes for cortical stimulation. Each spike pierces cortical tissue for better electrical contact. The art of implanting an intraocular prosthetic device to electrically stimulate the retina was advanced with the introduction of retinal tacks in retinal surgery. De Juan, et al. at Duke University Eye Center inserted retinal tacks into retinas in an effort to reattach retinas that had detached from the underlying choroid, which is the source of blood supply for the outer retina and thus the photoreceptors. See, e.g., E. de Juan, et al., 99 Am. J. Ophthalmol. 272 (1985). These retinal tacks have proved to be biocompatible and remain embedded in the retina, and choroid/sclera, effectively pinning the retina against the choroid and the posterior aspects of the globe. Humayun, U.S. Pat. No. 5,935,155 describes the use of retinal tacks to attach a retinal array to the retina. Alternatively, an electrode array may be attached by magnets or glue. U.S. Pat. No. 5,109,844 to de Juan describes a flat electrode array placed against the retina for visual stimulation. Any device for stimulating percepts in the retina must receive a signal describing a visual image along with power to operate the device. The device can not be powered by wires as any connection through the skin will create the risk of infection. Battery power is not practical as batteries are bulky and surgery is required to replace them. Such signal and power may be transmitted into the eye inductively as shown in Humayun U.S. Pat. No. 5,935,155. Humayun uses a primary (external) coil in front of the eye, possibly encased within the rim of a pair of glasses, and a secondary (internal) coil within the lens capsule or around the sclera just under the conjunctiva. Implanting within the lens capsule is difficult surgery and only allows for a small diameter coil. Larger coils are more efficient, can receive more power with less resulting temperature rise per unit of power received. Implanting around the sclera under the conjunctiva and near the surgical limbus (that is at the front of the eye) allows for a larger coil but may cause irritation or damage to the conjunctiva if the coil is placed in front near the cornea. U.S. patent application Ser. No. 09/761,270, Ok, discloses several coil configurations including a configuration where the coil is offset about 45 degrees from the front of the eye. The offset configuration allows the primary and secondary coils to be placed closer together allowing for better inductive coupling. The bridge of nose partially blocks placement of a primary coil when placed directly in front of the eye. A better configuration is needed allowing for close physical spacing of relatively large primary and secondary coils, without causing physical damages such as erosion of the conjunctiva. SUMMARY OF THE INVENTION The invention is a retinal prosthesis with an inductive coil mounted to the side of the eye by means of a strap around the eye. This allows for close coupling to an external coil and movement of the entire implanted portion with movement of the eye ball. Applicants have discovered that a coil around the sclera at or near 90 degrees rotation toward the lateral side of the eye has several advantages over previous designs. The secondary coil will not irritate the conjunctiva as it is placed against the sclera under the lateral rectus muscle, well behind the region where the conjunctiva attaches to the surgical limbus which is most susceptible to irritation. There is also more room between the conjunctiva and sclera on the side of the eye compared to the front of the eye. The primary coil can be placed on the temples of a pair of glasses and/or hidden by the user's hair. The spacing between primary and secondary coil can be as close, or closer, than that allowed for a coil pair located in the front of the eye or at a 45 degree angle because there are no eyelids or eyelashes to interfere with the coil. The skull is relatively flat and thin at the temple outside the lateral side of the eye. This allows for close coupling of the primary and secondary coils. The secondary coil can be mounted on the sclera under the lateral rectus muscle allowing the coil to move with the eye, avoiding the need for a cable that flexes with eye movement. A coil on the lateral side of the eye may be attached with a strap similar to a scleral buckle. A scleral buckle is a band of silicone placed around the eye and attached with a Watzke sleeve. A Watzke sleeve is a friction device that connects two silicone bands and holds them together with friction. Scleral buckles have been used to help hold the sclera against the retina when the retina has become detached. Scleral buckles are well known and many surgeons are skilled in their use, but using them to secure a device outside the eye is novel. Hence the secondary coil can be attached to, or integrated with, the strap and the strap placed around the sclera. In addition, suture tabs may be placed on the secondary coil to suture the coil to the sclera. The coil could also be affixed just by suturing to the sclera, without the use of a buckle. In another alternative, the device may initially float and become secured by the growth of the natural foreign body reaction to the presence of the device in the body. Further, an implanted electronics package is required to process and send the visual signal to the electrodes. It is advantageous to place the electronics package outside the sclera to aid heat dissipation. The electronics package can be attached to the strap or directly to the coil. This would not be possible with a front coil configuration as there is not enough room under the conjunctiva to accommodate the electronics package and coil near the limbus. Blind people are conscious of their appearance. Hence, the reason for hiding the primary coil in a pair of glasses. A coil on the side of the head can be hidden under the user's hair and/or incorporated in the design of glasses. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the implanted portion of the preferred retinal prosthesis. FIG. 2 is a side view of the implanted portion of the preferred retinal prosthesis showing the fan tail in more detail. FIG. 3 is an edge view of the implanted portion of the preferred retinal prosthesis showing the hook for aiding the implantation of the retinal prosthesis. FIG. 4 is an external profile view of a user wearing the external portion of the retinal prosthesis. FIG. 5 shows an alternate embodiment using a passive repeater coil pair. FIG. 6 show a second alternate embodiment using a coil in the temple region of the scull. DETAILED DESCRIPTION OF THE PREFERRED EMBODINENTS The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be determined with reference to the claims. FIG. 1 shows a perspective view of the implanted portion of the preferred retinal prosthesis. An electrode array 10 is mounted by a retinal tack or similar means to the epiretinal surface. The electrode array 10 is electrically coupled by a cable 12 which pierces the sclera and is electrically coupled to an electronics package 14, external to the sclera. The electronics package 14 is electrically coupled to a secondary inductive coil 16. Preferably the secondary inductive coil 16 is made from wound wire. Alternatively, the secondary inductive coil may be made from a thin film polymer sandwich with wire traces deposited between layers of thin film polymer. The electronics package 14 and secondary inductive coil 16 are held together by a molded body 18. The molded body 18 may also include suture tabs 20. The molded body narrows to form a strap 22 which surrounds the sclera and holds the molded body 18, secondary inductive coil 16, and electronics package 14 in place. The molded body 18, suture tabs 20 and strap 22 are preferably an integrated unit made of silicone elastomer. Silicone elastomer can be formed in a pre-curved shape to match the curvature of a typical sclera. However, silicone remains flexible enough to accommodate implantation and to adapt to variations in the curvature of an individual sclera. The secondary inductive coil 16 and molded body 18 are preferably oval shaped. A strap can better support an oval shaped coil. It should be noted that the entire implant is attached to and supported by the sclera. An eye moves constantly. The eye moves to scan a scene and also has a jitter motion to improve acuity. Even though such motion is useless in the blind, it often continues long after a person has lost their sight. It is an advantage of the present design, that the entire implanted portion of the prosthesis is attached to and supported by the sclera. By placing the device under the rectus muscles with the electronics package in an area of fatty issue between the rectus muscles, eye motion does not cause any flexing which might fatigue, and eventually damage, the device. FIG. 2 shows a side view of the implanted portion of the retinal prosthesis, in particular, emphasizing the fan tail 24. When implanting the retinal prosthesis, it is necessary to pass the strap 22 under the eye muscles to surround the sclera. The secondary inductive coil 16 and molded body 18 must also follow the strap under the lateral rectus muscle on the side of the sclera. The implanted portion of the retinal prosthesis is very delicate. It is easy to tear the molded body 18 or break wires in the secondary inductive coil 16. In order to allow the molded body 18 to slide smoothly under the lateral rectus muscle, the molded body is shaped in the form of a fan tail 24 on the end opposite the electronics package 14. Reinforced attachment points 26 are provided to facilitate handling of the retinal prosthesis by surgical tools. Preferably, the reinforced attachment points are harder silicone formed around holes through the molded body 18. Further, a hook 28 is molded into the strap 22 just beyond the end of the fan tail 24. A surgical tool can be used against the hook 28 to push the strap 22 under the rectus muscles. The hook 28 is more clearly depicted by the edge view of FIG. 3. The strap 22 is attached to itself by a sleeve 23. The sleeve 23 is a friction device that connects two silicone bands and holds them together with friction. The sleeve 23 is similar to a Watzke sleeve, used with a scleral buckle, and is well known in the art. In the preferred embodiment, the electrode array 10 and cable 12 are formed layers of a thin polymer film with metal traces sandwiched between the thin polymer films. In such an embodiment, it is advantageous that the film with openings for electrode array 10 be the same film with an opening for connection to the electronics package 14. Therefore, the cable 12 exits the electronics package up away from the fantail 24, folds over itself and exits down toward the fantail 24, before turning at a right angle and piercing the sclera. This allows the same side of the cable to face both the electronics package and the retina. The cable 12 may also include a fantail at the point it is attached to the electronics package 14 and at the point it is attached to the electrode array 10 to reduce any stress on the connections that may be caused by implantation. It is important that the cable exit the molded body 18 toward the front of the eye. The cable must travel above the lateral rectus muscle and pierce the sclera at the pars plana, in front of the retina, so it does not damage the retina. Once inside the eye, the cable 12 can fold back over the retina to properly locate the electrode array 10 on the epiretinal surface. FIG. 4 depicts the profile of a user wearing the external portion of the retinal prosthesis. The entire device may be built into the temple of a pair of glasses. A camera 30 collects a video image and transmits data to an external electronics package 32. A battery 34 powers the camera 30, external electronics package 32, and provides power to a primary inductive coil 36. The primary inductive coil 36 sends power and data through the skin and skull to the secondary inductive coil 16. Maximum efficiency is obtained when the primary inductive coil 36 and secondary inductive coil 16 are the same size, shape and as close together as possible. Referring to FIG. 5, an alternate embodiment uses a passive repeater coil pair. A passive secondary coil 42 is placed on the side of the scull in the temple region. Preferably, the passive secondary coil 42 is mounted just under the skin and attached to the temporalis muscle. Alternatively, the passive secondary coil 42 can be mounted wing of spheroid 46 (bone) just under the temporalis muscle. Once attached, wires may be routed though the inferior orbital fissure 48 into the eye socket 50, where a passive primary coil 44 is mounted to the scull inside the eye socket just over the lateral rectus muscle. The passive secondary coil 42 and passive primary coil 44 form the passive repeater coil pair. The passive repeater coil pair simply makes a more efficient path for power and data to travel from the primary inductive coil 36 to the secondary inductive coil 16. Referring to FIG. 6, a second alternate embodiment provides a remote secondary to inductive coil 52, mounted the same as the passive secondary coil 42. In this second alternative embodiment, wires from the remote secondary inductive coil 52 go directly to the electronics package 14. The electronics package 14 may be mounted with the remote secondary inductive coil 52 or on the sclera like the preferred embodiment. In either case, this second alternative embodiment provides the most efficient power use due to the close spacing of the primary inductive coil 36 and remote secondary inductive coil 52. However, this embodiment requires wires sufficiently flexible to accommodate eye movement without work hardening to the point a breaking. Accordingly, what has been shown is an improved retinal prosthesis. While the invention has been described by means of specific embodiments and applications thereof, it is understood that numerous modifications and variations could be made thereto by those skilled in the art without departing from the spirit and scope of the invention. It is therefore to be understood that within the scope of the claims, the invention may be practiced otherwise than as specifically described herein. | <SOH> BACKGROUND OF THE INVENTION <EOH>In 1755 LeRoy passed the discharge of a Leyden jar through the orbit of a man who was blind from cataract and the patient saw “flames passing rapidly downwards.” Ever since, there has been a fascination with electrically elicited visual perception. The general concept of electrical stimulation of retinal cells to produce these flashes of light or phosphenes has been known for quite some time. Based on these general principles, some early attempts at devising a prosthesis for aiding the visually impaired have included attaching electrodes to the head or eyelids of patients. While some of these early attempts met with some limited success, these early prosthetic devices were large, bulky and could not produce adequate simulated vision to truly aid the visually impaired. In the early 1930's, Foerster investigated the effect of electrically stimulating the exposed occipital pole of one cerebral hemisphere. He found that, when a point at the extreme occipital pole was stimulated, the patient perceived a small spot of light directly in front and motionless (a phosphene). Subsequently, Brindley and Lewin (1968) thoroughly studied electrical stimulation of the human occipital (visual) cortex. By varying the stimulation parameters, these investigators described in detail the location of the phosphenes produced relative to the specific region of the occipital cortex stimulated. These experiments demonstrated: (1) the consistent shape and position of phosphenes; (2) that increased stimulation pulse duration made phosphenes brighter; and (3) that there was no detectable interaction between neighboring electrodes which were as close as 2.4 mm apart. As intraocular surgical techniques have advanced, it has become possible to apply stimulation on small groups and even on individual retinal cells to generate focused phosphenes through devices implanted within the eye itself. This has sparked renewed interest in developing methods and apparati to aid the visually impaired. Specifically, great effort has been expended in the area of intraocular retinal prosthesis devices in an effort to restore vision in cases where blindness is caused by photoreceptor degenerative retinal diseases such as retinitis pigmentosa and age related macular degeneration which affect millions of people worldwide. Neural tissue can be artificially stimulated and activated by prosthetic devices that pass pulses of electrical current through electrodes on such a device. The passage of current causes changes in electrical potentials across visual neuronal membranes, which can initiate visual neuron action potentials, which are the means of information transfer in the nervous system. Based on this mechanism, it is possible to input information into the nervous system by coding the information as a sequence of electrical pulses which are relayed to the nervous system via the prosthetic device. In this way, it is possible to provide artificial sensations including vision. One typical application of neural tissue stimulation is in the rehabilitation of the blind. Some forms of blindness involve selective loss of the light sensitive transducers of the retina. Other retinal neurons remain viable, however, and may be activated in the manner described above by placement of a prosthetic electrode device on the inner (toward the vitreous) retinal surface (epiretinal). This placement must be mechanically stable, minimize the distance between the device electrodes and the visual neurons, and avoid undue compression of the visual neurons. In 1986, Bullara (U.S. Pat. No. 4,573,481) patented an electrode assembly for surgical implantation on a nerve. The matrix was silicone with embedded iridium electrodes. The assembly fit around a nerve to stimulate it. Dawson and Radtke stimulated cat's retina by direct electrical stimulation of the retinal ganglion cell layer. These experimenters placed nine and then fourteen electrodes upon the inner retinal layer (i.e., primarily the ganglion cell layer) of two cats. Their experiments suggested that electrical stimulation of the retina with 30 to 100 uA current resulted in visual cortical responses. These experiments were carried out with needle-shaped electrodes that penetrated the surface of the retina (see also U.S. Pat. No. 4,628,933 to Michelson). The Michelson '933 apparatus includes an array of photosensitive devices on its surface that are connected to a plurality of electrodes positioned on the opposite surface of the device to stimulate the retina. These electrodes are disposed to form an array similar to a “bed of nails” having conductors which impinge directly on the retina to stimulate the retinal cells. U.S. Pat. No. 4,837,049 to Byers describes spike electrodes for neural stimulation. Each spike electrode pierces neural tissue for better electrical contact. U.S. Pat. No. 5,215,088 to Norman describes an array of spike electrodes for cortical stimulation. Each spike pierces cortical tissue for better electrical contact. The art of implanting an intraocular prosthetic device to electrically stimulate the retina was advanced with the introduction of retinal tacks in retinal surgery. De Juan, et al. at Duke University Eye Center inserted retinal tacks into retinas in an effort to reattach retinas that had detached from the underlying choroid, which is the source of blood supply for the outer retina and thus the photoreceptors. See, e.g., E. de Juan, et al., 99 Am. J. Ophthalmol. 272 (1985). These retinal tacks have proved to be biocompatible and remain embedded in the retina, and choroid/sclera, effectively pinning the retina against the choroid and the posterior aspects of the globe. Humayun, U.S. Pat. No. 5,935,155 describes the use of retinal tacks to attach a retinal array to the retina. Alternatively, an electrode array may be attached by magnets or glue. U.S. Pat. No. 5,109,844 to de Juan describes a flat electrode array placed against the retina for visual stimulation. Any device for stimulating percepts in the retina must receive a signal describing a visual image along with power to operate the device. The device can not be powered by wires as any connection through the skin will create the risk of infection. Battery power is not practical as batteries are bulky and surgery is required to replace them. Such signal and power may be transmitted into the eye inductively as shown in Humayun U.S. Pat. No. 5,935,155. Humayun uses a primary (external) coil in front of the eye, possibly encased within the rim of a pair of glasses, and a secondary (internal) coil within the lens capsule or around the sclera just under the conjunctiva. Implanting within the lens capsule is difficult surgery and only allows for a small diameter coil. Larger coils are more efficient, can receive more power with less resulting temperature rise per unit of power received. Implanting around the sclera under the conjunctiva and near the surgical limbus (that is at the front of the eye) allows for a larger coil but may cause irritation or damage to the conjunctiva if the coil is placed in front near the cornea. U.S. patent application Ser. No. 09/761,270, Ok, discloses several coil configurations including a configuration where the coil is offset about 45 degrees from the front of the eye. The offset configuration allows the primary and secondary coils to be placed closer together allowing for better inductive coupling. The bridge of nose partially blocks placement of a primary coil when placed directly in front of the eye. A better configuration is needed allowing for close physical spacing of relatively large primary and secondary coils, without causing physical damages such as erosion of the conjunctiva. | <SOH> SUMMARY OF THE INVENTION <EOH>The invention is a retinal prosthesis with an inductive coil mounted to the side of the eye by means of a strap around the eye. This allows for close coupling to an external coil and movement of the entire implanted portion with movement of the eye ball. Applicants have discovered that a coil around the sclera at or near 90 degrees rotation toward the lateral side of the eye has several advantages over previous designs. The secondary coil will not irritate the conjunctiva as it is placed against the sclera under the lateral rectus muscle, well behind the region where the conjunctiva attaches to the surgical limbus which is most susceptible to irritation. There is also more room between the conjunctiva and sclera on the side of the eye compared to the front of the eye. The primary coil can be placed on the temples of a pair of glasses and/or hidden by the user's hair. The spacing between primary and secondary coil can be as close, or closer, than that allowed for a coil pair located in the front of the eye or at a 45 degree angle because there are no eyelids or eyelashes to interfere with the coil. The skull is relatively flat and thin at the temple outside the lateral side of the eye. This allows for close coupling of the primary and secondary coils. The secondary coil can be mounted on the sclera under the lateral rectus muscle allowing the coil to move with the eye, avoiding the need for a cable that flexes with eye movement. A coil on the lateral side of the eye may be attached with a strap similar to a scleral buckle. A scleral buckle is a band of silicone placed around the eye and attached with a Watzke sleeve. A Watzke sleeve is a friction device that connects two silicone bands and holds them together with friction. Scleral buckles have been used to help hold the sclera against the retina when the retina has become detached. Scleral buckles are well known and many surgeons are skilled in their use, but using them to secure a device outside the eye is novel. Hence the secondary coil can be attached to, or integrated with, the strap and the strap placed around the sclera. In addition, suture tabs may be placed on the secondary coil to suture the coil to the sclera. The coil could also be affixed just by suturing to the sclera, without the use of a buckle. In another alternative, the device may initially float and become secured by the growth of the natural foreign body reaction to the presence of the device in the body. Further, an implanted electronics package is required to process and send the visual signal to the electrodes. It is advantageous to place the electronics package outside the sclera to aid heat dissipation. The electronics package can be attached to the strap or directly to the coil. This would not be possible with a front coil configuration as there is not enough room under the conjunctiva to accommodate the electronics package and coil near the limbus. Blind people are conscious of their appearance. Hence, the reason for hiding the primary coil in a pair of glasses. A coil on the side of the head can be hidden under the user's hair and/or incorporated in the design of glasses. | 20040406 | 20070605 | 20051006 | 62953.0 | 0 | ANTHONY, JESSICA LYNN | RETINAL PROSTHESIS WITH SIDE MOUNTED INDUCTIVE COIL | SMALL | 0 | ACCEPTED | 2,004 |
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10,820,395 | ACCEPTED | Calcium chloride purification | Significant amounts of soluble fluoride, known to create problems in processes requiring high quality grade calcium chloride, are removed from calcium chloride solution using hydroxyapatite as a removal mechanism. Under acidic conditions, calcium chloride solution is purified to about less than 10 ppm fluoride, significantly, to less than 1 ppm fluoride. At least 0.1 weight percent hydroxyapatite and concentrated hydrochloric acid are added to calcium chloride solution and slurried to remove fluoride and create a highly purified calcium chloride solution, substantially free of fluoride. | 1. A method of removing fluoride from calcium chloride comprising mixing calcium chloride solution with hydroxyapatite in the presence of an acid. 2. The method of claim 1 wherein said hydroxyapatite is 0.1 to 5 weight percent tri-calciumphosphate. 3. The method of claim 1 wherein the acid is hydrochloric acid. 4. The method of claim 1 wherein the hydrochloric acid is added in an amount sufficient to obtain a pH of less than about 2. 5. A method for removing soluble fluoride from a calcium chloride solution comprising: mixing said calcium chloride solution with hydroxyapatite and an acid to form a slurry at a pH less than about 2 for at least 1 minute, and filtering out a purified calcium chloride solution. 6. The method of claim 5 wherein the concentration of said hydroxyapatite is in the range of from about 0.1 to 5 weight percent. 7. The method of claim 5 wherein the concentration of soluble fluoride in the purified calcium chloride solution is in the range of 0 to 10 ppm. 8. The method of claim 5 wherein the acid is hydrochloric acid. 9. A method for producing ultra-low fluoride food-grade calcium chloride comprising mixing a calcium chloride solution with hydroxyapatite and an acid to form a slurry at a pH of less than 2 for at least 1 minute, and filtering out purified calcium chloride solution. 10. A method of producing calcium chloride with an ultra-low fluoride concentration comprising mixing hydroxyapatite, hydrochloric acid, and a calcium source. 11. The method of claim 11 wherein said calcium source is calcium carbonate or lime. | FIELD OF THE INVENTION This invention relates in general to a process for removing fluoride by ion exchange. Specifically, this invention relates to a process for manufacturing low fluoride calcium chloride, or removing soluble fluoride from calcium chloride using a naturally occurring mineral to purify the calcium chloride. More specifically, this invention relates to a process for purifying calcium chloride by removing soluble fluoride using hydroxyapatite. BACKGROUND OF THE INVENTION Calcium chloride is used in different applications, some of which require “food-grade” calcium chloride that contains low concentrations of fluorides and other contaminants. For example, calcium chloride is used in bisphenol-A plants to break the hydrochloric acid/water azeotrope in hydrochloric acid recovery columns. In this particular application, fluoride ions will concentrate and convert to hydrogen fluoride in the HCl recovery column. Hydrogen fluoride, known to dissolve glass, creates pin holes in the recovery column, disrupting the recovery process and creating leakage problems. “Food grade” calcium chloride is also used in actual food applications, which naturally require high quality materials. The fluoride concentration in “food-grade” calcium chloride is typically less than 10 ppm. However, this grade of calcium chloride is often difficult to obtain and is therefore expensive. It would thus be desirable to remove the fluoride ions from the calcium chloride solution prior to its use in applications requiring low-fluoride, or “food grade” quality calcium chloride. Many present methods for removing fluoride ions from process and wastewater streams are inadequate or cost prohibitive for obtaining the desired fluoride-free calcium chloride solution because they are inapplicable when calcium and chloride concentrations are high. U.S. Pat. No. 6,355,221 to Rappas and U.S. Pat. No. 5,403,495 to Kust et al. teach the use of calcium fluoride as a seed for creating enhanced calcium fluoride particles in order to remove soluble fluoride from the wastewater streams. The use of adsorbents to remove fluoride ions in solution has also been effective under certain conditions. For example, European Patent No. EP0191893 to Nomura et al. discloses contacting a solution containing fluorine compounds with various hydrated rare earth oxide adsorbents. Similarly, International Publication No. WO 98/10851 teaches the removal of fluoride ions in solution by passing the solution through an ion exchange resin to produce an ultrapure hydrofluoric acid. However, these methods do not solve the problem of removing fluoride ions from solutions containing high calcium and chloride ion concentrations, thereby generating a purified calcium chloride stream for use in later processing. These methods also do not produce a calcium chloride solution with as little as less than 1 ppm of fluoride. It would also be advantageous to have an easy, cost-effective method of manufacturing low fluoride calcium chloride. SUMMARY Briefly, the invention relates to a method for removing fluoride from aqueous solution. More specifically, the invention relates to the removal of soluble fluoride from a calcium chloride solution to produce purified calcium chloride with extremely low concentrations of fluoride in the range of 0 to 10 ppm. In one embodiment of the present invention, fluoride is removed from calcium chloride solution by causing ion exchange between the solution and an ion-containing material. According to one aspect of this invention, the ion-containing material is a natural material that is mixed with the calcium chloride in the form of a slurry. Ion exchange occurs whereby the fluoride ions in solution are substituted for the hydroxide ions in the material. The natural material is hydroxyapatite, or calcium phosphate/calcium hydroxide composite. The contact between the fluoride ions and the slurry causes ion exchange between the solution and slurry, causing adsorption of the fluoride ions. Chloride ions are too big to exchange for hydroxide ions in the hydroxyapatite matrix, therefore the chloride ions stay in solution. The solubility of fluoridated hydroxyapatite is extremely small. The solubility product, Ksp of fluor-hydroxyapatite, is Ca10(PO4)6(F2OH)2 is 3.16×10−60 (Saliva and Tooth Dissolution, http://www.ncl.ac.uk/dental/oralbiol/oralenv/tutorials/calciumphosphate.htm, Jul. 16, 2003). As a result, the fluoride ions remain in the hydroxyapatite matrix and do not re-enter solution during the purification process. The resulting purified calcium chloride solution is filtered out or removed from the slurry according to the designated application or end use for the product. The resulting product has a fluoride concentration of as low as less than 1 ppm, and has broad uses in applications requiring ultra low fluoride concentration calcium chloride. According to another embodiment of the present invention, calcium chloride with ultra low fluoride concentrations is manufactured by mixing lime or calcium carbonate with aqueous hydrochloric acid and calciumtriphosphate or other hydroxyapatite in a slurry process. Kirk-Othmer Encyclopedia, Vol. 4, p. 790, describes a process to make calcium halides by reaction of calciumcarbonate, calcium oxide, or lime with hydrohalic acid. In a similar process, calcium carbonate or lime can be mixed with hydrochloric acid and hydroxyapatite to create calcium chloride that has an ultra-low fluoride concentration. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a graph of percentage of fluoride removal over time with 0.5 weight percent hydroxyapatite and no acid addition. FIG. 2 is a graph of fluoride removal over time with a final acid concentration of 0.075 weight percent hydrochloric acid and varying amounts of hydroxyapatite. FIG. 3 is another graph of fluoride removal over an extended time period with a final acid concentration of 0.075 weight percent hydrochloric acid and varying amounts of hydroxyapatite. DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method of using hydroxyapatite to remove fluorides and purify calcium chloride solution. Hydroxyapatite is preferably slurried into calcium chloride solution and acid is added to lower the pH during the purification process. Calcium chloride solutions of 30 to 35 weight percent calcium chloride typically contain 10 to 100 ppm of fluoride. The method of the present invention cuts the fluoride concentration to less than 10 ppm in solution. According to one embodiment of the present invention, an aqueous solution of calcium chloride, hydroxyapatite and hydrochloric acid are slurried in a reaction vessel. Preferably, 0.5 weight percent hydroxyapatite and concentrated hydrochloric acid (approximately 35 to 38 weight percent) are slurried into calcium chloride for at least 1 minute. The final acid concentration in solution is approximately 0.08 percent by volume. Preferably, the reaction is carried out for less than 48 hours at a temperature less than about 200° F., more preferably less than 24 hours and between 50 to 150° F. After the reaction is complete, the purified calcium chloride solution is filtered, or removed using some other method. The pH of the reaction slurry has a significant impact on purification of the calcium chloride. As illustrated on FIG. 1, at 72° F., 0.5 weight percent hydroxyapatite, and no acid addition, only 35% of the fluoride ions present in calcium chloride solution were removed after approximately 24 hours. With the addition of concentrated hydrochloric acid to obtain a solution with a final acid concentration of 0.075 percent by volume hydrochloric acid (a pH of less than 1), and the addition of 0.5 weight percent hydroxyapatite, at approximately 140° F., fluoride removal increased to 95% in less than 20 minutes as illustrated on FIGS. 2 and 3. Referring to Table 1 below, at 140° F. and 0.5 weight percent hydroxyapatite, the addition of acid per 100 grams of 35 weight percent calcium chloride solution significantly increases fluoride removal after 4 hours of reaction time: TABLE 1 HCl (acid drops/100 g CaCl2) Fluoride Removal (%) 0 41 1 65 2 88 Similarly, the hydroxyapatite concentration has a significant impact on the purification process, as illustrated in Table 2 below. The following fluoride removal percentages were realized at different concentrations of hydroxyapatite addition after 20 minutes of reaction time with fluoride contaminated calcium chloride: TABLE 2 In-solution weight percent Resulting Fluoride of hydroxyapatite Fluoride Removal (%) Conc. (ppm) 0.0 2 18.7 0.1 34 12.5 0.25 79 4.0 0.5 95 1.0 The following Examples illustrate one embodiment of the present invention for fluoride removal from 200 grams of 35 weight percent aqueous calcium chloride solution. FIGS. 2 and 3 plot the results of fluoride removal according to the process carried out in these Examples. EXAMPLE 1 200 grams of calcium chloride feedstock was slurried with 150 microliters of concentrated HCl to a final acid concentration of 0.075 weight percent in a batch reactor at 140° F. with no hydroxyapatite. After 6 hours, the fluoride concentration was reduced by only about 6 percent, from a concentration of 18.8 ppm to a concentration of 16.7 ppm. EXAMPLE 2 200 grams of calcium chloride feedstock was slurried with 150 μL of concentrated HCl to a final acid concentration of 0.075 weight percent and 0.21 grams hydroxyapatite (0.1 weight percent in solution) in a batch reactor at 140° F. The starting fluoride concentration in the calcium chloride feedstock was approximately 18.8 ppm. After 5 minutes, approximately 28 percent reduction in fluoride was realized; the fluoride concentration was reduced to 13.6 ppm. After 24 hours, approximately 70 percent reduction in fluoride was realized, the final fluoride concentration at 5.7 ppm. EXAMPLE 3 200 grams of calcium chloride feedstock was slurried with 150 μL of concentrated HCl (to a final acid concentration of 0.075 weight percent and a pH of −0.2) and 0.5 grams of hydroxyapatite (0.25 weight percent in solution) in a batch reactor at approximately 140° F. Fluoride removal occurred exponentially, as indicated on Table 2. After 5 minutes, the fluoride concentration was reduced from 18.8 ppm to 10.6 ppm, an approximate 44 percent reduction in fluoride concentration, and after approximately 24 hours, the fluoride concentration was measured at approximately 1.0, an approximate 95 percent reduction. EXAMPLE 4 In another example, 1.01 g of tricalciumphosphate (0.5 weight percent in solution) and 150 μL of concentrated HCl were slurried in 200 grams of calcium chloride feedstock at 133° F. The solution pH was 0.08. The untreated feedstock contained approximately 19 ppm fluoride. After 15 minutes, the fluoride concentration was reduced to 0.8 ppm, and after 24 hours, approximately 98 percent was removed, a final measured fluoride concentration of approximately 0.4 ppm. As illustrated herein, under acidic conditions, preferably a pH less than 2, and more preferably a pH less than 1, with the addition of hydroxyapatite to calcium chloride solution that contains unwanted contaminants, significant fluoride removal is obtained. According to yet another embodiment of the present invention, an aqueous solution of hydroxyapatite, hydrochloric acid, and calcium carbonate or lime are slurried in a reaction vessel to produce low-fluoride calcium chloride solution. Methods of manufacturing calcium chloride, and other calcium compounds, are well known in the industry. For example, the Kirk-Othmer Encyclopedia, Vol. 4, p. 790, describes a method of making calcium halides by reacting calcium carbonate, calcium oxide, or lime with hydrochloric acid. The addition of hydroxyapatite to known processes for manufacturing calcium chloride greatly increases fluoride removal to produce ultra-low fluoride containing calcium chloride solutions. The foregoing illustrations of embodiments of the present invention are offered for the purposes of illustration and not limitation. It will be readily apparent to those skilled in the art that the embodiments described herein may be modified or revised in various ways without departing from the spirit and scope of the invention. The scope of the invention is to be measured by the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>Calcium chloride is used in different applications, some of which require “food-grade” calcium chloride that contains low concentrations of fluorides and other contaminants. For example, calcium chloride is used in bisphenol-A plants to break the hydrochloric acid/water azeotrope in hydrochloric acid recovery columns. In this particular application, fluoride ions will concentrate and convert to hydrogen fluoride in the HCl recovery column. Hydrogen fluoride, known to dissolve glass, creates pin holes in the recovery column, disrupting the recovery process and creating leakage problems. “Food grade” calcium chloride is also used in actual food applications, which naturally require high quality materials. The fluoride concentration in “food-grade” calcium chloride is typically less than 10 ppm. However, this grade of calcium chloride is often difficult to obtain and is therefore expensive. It would thus be desirable to remove the fluoride ions from the calcium chloride solution prior to its use in applications requiring low-fluoride, or “food grade” quality calcium chloride. Many present methods for removing fluoride ions from process and wastewater streams are inadequate or cost prohibitive for obtaining the desired fluoride-free calcium chloride solution because they are inapplicable when calcium and chloride concentrations are high. U.S. Pat. No. 6,355,221 to Rappas and U.S. Pat. No. 5,403,495 to Kust et al. teach the use of calcium fluoride as a seed for creating enhanced calcium fluoride particles in order to remove soluble fluoride from the wastewater streams. The use of adsorbents to remove fluoride ions in solution has also been effective under certain conditions. For example, European Patent No. EP0191893 to Nomura et al. discloses contacting a solution containing fluorine compounds with various hydrated rare earth oxide adsorbents. Similarly, International Publication No. WO 98/10851 teaches the removal of fluoride ions in solution by passing the solution through an ion exchange resin to produce an ultrapure hydrofluoric acid. However, these methods do not solve the problem of removing fluoride ions from solutions containing high calcium and chloride ion concentrations, thereby generating a purified calcium chloride stream for use in later processing. These methods also do not produce a calcium chloride solution with as little as less than 1 ppm of fluoride. It would also be advantageous to have an easy, cost-effective method of manufacturing low fluoride calcium chloride. | <SOH> SUMMARY <EOH>Briefly, the invention relates to a method for removing fluoride from aqueous solution. More specifically, the invention relates to the removal of soluble fluoride from a calcium chloride solution to produce purified calcium chloride with extremely low concentrations of fluoride in the range of 0 to 10 ppm. In one embodiment of the present invention, fluoride is removed from calcium chloride solution by causing ion exchange between the solution and an ion-containing material. According to one aspect of this invention, the ion-containing material is a natural material that is mixed with the calcium chloride in the form of a slurry. Ion exchange occurs whereby the fluoride ions in solution are substituted for the hydroxide ions in the material. The natural material is hydroxyapatite, or calcium phosphate/calcium hydroxide composite. The contact between the fluoride ions and the slurry causes ion exchange between the solution and slurry, causing adsorption of the fluoride ions. Chloride ions are too big to exchange for hydroxide ions in the hydroxyapatite matrix, therefore the chloride ions stay in solution. The solubility of fluoridated hydroxyapatite is extremely small. The solubility product, Ksp of fluor-hydroxyapatite, is Ca 10 (PO 4 ) 6 (F 2 OH) 2 is 3.16×10 −60 ( Saliva and Tooth Dissolution , http://www.ncl.ac.uk/dental/oralbiol/oralenv/tutorials/calciumphosphate.htm, Jul. 16, 2003). As a result, the fluoride ions remain in the hydroxyapatite matrix and do not re-enter solution during the purification process. The resulting purified calcium chloride solution is filtered out or removed from the slurry according to the designated application or end use for the product. The resulting product has a fluoride concentration of as low as less than 1 ppm, and has broad uses in applications requiring ultra low fluoride concentration calcium chloride. According to another embodiment of the present invention, calcium chloride with ultra low fluoride concentrations is manufactured by mixing lime or calcium carbonate with aqueous hydrochloric acid and calciumtriphosphate or other hydroxyapatite in a slurry process. Kirk-Othmer Encyclopedia, Vol. 4, p. 790, describes a process to make calcium halides by reaction of calciumcarbonate, calcium oxide, or lime with hydrohalic acid. In a similar process, calcium carbonate or lime can be mixed with hydrochloric acid and hydroxyapatite to create calcium chloride that has an ultra-low fluoride concentration. | 20040408 | 20060502 | 20051013 | 95882.0 | 0 | NGUYEN, NGOC YEN M | CALCIUM CHLORIDE PURIFICATION | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,820,520 | ACCEPTED | Talker arbitration method and apparatus | During the course of a push-to-talk talkgroup wireless communication, decisions (21) are made regarding possible subsequent push-to-talk communication needs for the group. Based at least in part upon such decisions, a network location is identified (22) to provide talker arbitration support for this talkgroup. In one embodiment the identified network location can comprise a mobile station, such as a mobile station that comprises a member of the talkgroup. In a preferred embodiment, the talker arbitration capability is then assigned (24) to the identified network location. | 1. A method comprising: subsequent to initiation of a push-to-talk wireless communication for a talk group; automatically considering at least one possible subsequent push-to-talk communication need of the talk group to provide at least one corresponding determination; automatically identifying a network location to support talker arbitration for the push-to-talk communication needs of the talk group as a function, at least in part, of the corresponding determination. 2. The method of claim 1 wherein the talk group comprises a first mobile station and a second mobile station. 3. The method of claim 2 wherein the talk group further comprises at least a third mobile station. 4. The method of claim 1 wherein subsequent to initiation of a push-to-talk wireless communication for a talk group further comprises at least partially during a time when an active wireless channel is allocated to support the push-to-talk wireless communication. 5. The method of claim 1 wherein automatically considering at least one possible subsequent push-to-talk communication need of the talk group further comprises automatically identifying at least one target mobile station to whom a present push-to-talk wireless communication is directed. 6. The method of claim 5 wherein automatically identifying a network location to support talker arbitration for the push-to-talk communication needs of the talk group as a function, at least in part, of the corresponding determination further comprises identifying the target mobile station as the network location to support talker arbitration for the push-to-talk communication needs of the talk group. 7. The method of claim 1 wherein automatically considering at least one possible subsequent push-to-talk communication need of the talk group further comprises automatically considering at least one item of context information regarding the talk group. 8. The method of claim 7 wherein automatically considering at least one item of context information regarding the talk group further comprises automatically considering at least one of: voice recognition results as correspond to analysis of at least a part of a push-to-talk wireless communication; determining which mobile station of the talk group appears to likely comprise a discussion leader; determining which mobile station of the talk group comprises an originating mobile station as regards the push-to-talk wireless communication; user manipulation of a mobile station; push-to-talk wireless communications historical information; identification of a most frequent initiator of push-to-talk communications; geographic location of at least one member of the talk group; a presence of other concurrently used services. the type or length of the previous push-to-talk communication the target's current status as being in a meeting or not as inferred, for example, from a calendar meeting schedule for the target; the number of members in the push-to-talk group. the RF congestion, frame erasure rate or link speed achieved 9. The method of claim 1 wherein automatically identifying a network location further comprises identifying a mobile station that comprises a member of the talk group. 10. The method of claim 1 wherein automatically identifying a network location further comprises identifying a network server. 11. The method of claim 1 and further comprising: automatically assigning the network location to support talker arbitration for the talk group. 12. The method of claim 11 wherein automatically assigning the network location to support talker arbitration for the talk group further comprises transmitting at least one explicit message to the network location to indicate assignment of talker arbitration to the network location. 13. The method of claim 11 wherein automatically assigning the network location to support talker arbitration for the talk group further comprises transmitting a signal to the network location to indicate assignment of talker arbitration to the network location. 14. The method of claim 11 and further comprising: intentionally delaying automatically assigning the network location to support talker arbitration for the talk group. 15. The method of claim 14 wherein intentionally delaying automatically assigning the network location to support talker arbitration for the talk group further comprises intentionally delaying, for at least a predetermined period of time, automatically assigning the network location to support talker arbitration for the talk group. 16. The method of claim 15 and further comprising: detecting, while intentionally delaying automatically assigning the network location, a condition of interest; automatically identifying a network location to support talker arbitration for the push-to-talk communication needs of the talk group as a function, at least in part, of the condition of interest. 17. The method of claim 16 wherein detecting a condition of interest further comprises detecting that a just-previous transmitting mobile station is seeking to initiate a subsequent push-to-talk wireless communication. 18. A method for use with a wireless push-to-talk mobile station, comprising: participating in a push-to-talk wireless communication with a talk group; activating talker arbitration capability for the talk group. 19. The method of claim 18 wherein activating talker arbitration capability further comprises activating talker arbitration capability in response to receiving at least a first predetermined signal. 20. The method of claim 19 wherein receiving at least a first predetermined signal further comprises receiving an explicit instruction to activate the talker arbitration capability. 21. The method of claim 19 wherein receiving at least a first predetermined signal further comprises receiving an end-of-transmission signal. 22. The method of claim 18 and further comprising deactivating the talker arbitration capability. 23. A wireless push-to-talk mobile station comprising: a processing platform; at least a first memory having push-to-talk talker arbitration instructions stored therein. 24. The wireless push-to-talk mobile station of claim 23 and further comprising means for activating the push-to-talk talker arbitration instructions in response to detection of at least a first predetermined condition. 25. The wireless push-to-talk mobile station of claim 23 and further comprising means for using the push-to-talk talker arbitration instructions to arbitrate at least one push-to-talk communication for a talk group that includes the wireless push-to-talk mobile station. | TECHNICAL FIELD This invention relates generally to wireless communication systems and more particularly to so-called push-to-talk wireless communications. BACKGROUND Push-to-talk styled communications are well known in the art. The members of a talkgroup comprising two or more wireless mobile stations are able to wirelessly communicate with one another by simply asserting a push-to-talk button. In many communication systems, assertion of the push-to-talk button does not immediately permit the user to begin talking (and/or transmitting). Instead, assertion of the push-to-talk button initiates a sequence of events whereby the mobile station requests and/or otherwise acquires a communication resource (such as a specific transmission frequency, time slot(s), and/or a spreading code, to name a few) to facilitate the desired communication. In such systems, a specific audible signal will usually be provided to the user when, subsequent to assertion of the push-to-talk button, the mobile station in fact is prepared to at least record and then, usually, to shortly later transmit the user's message. The duration of delay between when the user first asserts the push-to-talk button and when the user receives the signal indicating that the speech may now commence can vary for a variety of reasons. This delay, however, often becomes an obvious and highly visible measure of quality of service for many users. In general, the shorter the delay, the higher the perception of service quality. In some cases this delay occurs due to circumstances beyond immediate control (for example, high system loading or infrastructure downtime can adversely impact system performance in this regard). In many instances, however, this delay cannot be reasonably reduced below a minimal duration that is nevertheless a source of disappointment to at least some users. Talker arbitration requirements comprise one such example. Talker arbitration facilitates a decision process whereby the communication system responds to a push-to-talk talk request by ascertaining whether any higher priority (and/or earlier) talk request presents a conflict and arbitrates such a conflict through selection of only one of the requesting parties. A dispatch server usually supports the talker arbitration service in most such systems. Even when only a single wireless station presently seeks to communicate (i.e., when there is no present conflict) the wireless station must still transmit its intentions to the talker arbitrator at the dispatch server, and the talker arbitrator must still conclude the talker arbitration process and communicate its communication grant (or approval) to the requesting wireless station. This overall process can easily consume 700 milliseconds (or more) even under relatively ideal operating conditions in many systems. This minimal delay floor can lead to a sense of dissatisfaction with respect to the operation and efficiency of the wireless station and/or the communication system. BRIEF DESCRIPTION OF THE DRAWINGS The above needs are at least partially met through the provisioning of the talker arbitration method and apparatus described in the following detailed description, particularly when studied in conjunction with the drawings, wherein: FIG. 1 comprises a block diagram as configured in accordance with various embodiments of the invention; FIG. 2 comprises a flow diagram as configured in accordance with various embodiments of the invention; FIG. 3 comprises a flow diagram as configured in accordance with various embodiments of the invention; FIG. 4 comprises a signal flow diagram as configured in accordance with various embodiments of the invention; FIG. 5 comprises a signal flow diagram as configured in accordance with various embodiments of the invention; and FIG. 6 comprises a signal flow diagram as configured in accordance with various embodiments of the invention. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or placement of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will also be understood that the terms and expressions used herein have the ordinary meaning as is usually accorded to such terms and expressions by those skilled in the corresponding respective areas of inquiry and study except where other specific meanings have otherwise been set forth herein. DETAILED DESCRIPTION Generally speaking, pursuant to these various embodiments, talker arbitration functionality is dynamically moved between various network elements in order to potentially achieve reduced push-to-talk delay. Depending upon the embodiment, such functionality can be moved among various dispatch servers. In a preferred embodiment, the talker arbitration functionality can be moved to, and effected by, one of the wireless mobile stations of a given talk group. Pursuant to one embodiment, and subsequent to initiation of a push-to-talk wireless communication for a talk group, a preferred process automatically considers at least one possible subsequent push-to-talk communication need of the talk group to thereby provide at least one corresponding determination in this regard. This determination then provides a basis for automatically identifying a network location to support talker arbitration for the push-to-talk communication needs of the talk group. Assessing the possible subsequent push-to-talk communication needs of a talk group can be based upon a wide variety of criteria including, but not limited to, the identity of a presently transmitting mobile station, the identify of a presently receiving mobile station, and any of a wide variety of items of context information regarding the talk group. Such items of context information can comprise, but are not limited to, voice recognition results as correspond to analysis of at least a part of a push-to-talk wireless communication, determining which mobile station of the talk group appears to likely comprise a discussion leader, user manipulation of a mobile station, push-to-talk wireless communications historical information, identification of a most frequent initiator of push-to-talk communications, a geographic location of at least one member of the talk group, and a presence or absence of other concurrently used services, to name a few. So configured, by appropriately pre-placing talker arbitration functionality, considerable delay time can potentially be avoided. In many instances a user will be notified of talk approval in less time than is usually presently possible. For example, in a multi-server system, one may choose to place the talker arbitration functionality in a server that is closer (in terms of “delay,” where distance or other propagation issues and phenomena can be contributing factors) to the mobile or mobiles that are most likely to next assert a push-to-talk. For example, in a group or private call with one party in San Francisco and another party in Washington, D.C., and where there is a dispatch server in each of the two cities, one might decide to place the talker arbitration capability at the server in the city of the mobile station that just received a last audio segment, or one might decide to place the talker arbitration capability in the city where most of the parties in the group call are presently located. Referring now to the drawings, and in particular to FIG. 1, a suitable platform 10 to support this flexible approach will typically comprise a processing platform 11 and a corresponding memory 12. In a preferred embodiment the memory 12 will at least have push-to-talk talker arbitration instructions stored therein (i.e., programming to permit the processing platform 11 to effect the talker arbitration task(s)). The processing platform 11 itself comprises a mechanism to facilitate the activation and use of push-to-talk talker arbitration instructions in response, for example, to detection of a predetermined condition such as a trigger event or condition. So configured, the processing platform 11 can selectively serve to use such push-to-talk arbitration instructions to arbitrate push-to-talk communications for one or more talk groups. Such a processing platform 11 can be disposed as appropriate to the needs of a given application. For example, pursuant to one embodiment, the processing platform 11 can comprise a part of a dispatch server. Pursuant to another embodiment, this apparatus 10 can comprise a wireless push-to-talk mobile station. Other elements, components, and functionality as appropriate to such embodiments can of course be included as appropriate and as would otherwise be well understood in the art. As one illustration of this point, when this apparatus 10 comprises a wireless push-to-talk mobile station, the processing platform 11 will likely operably couple to a wireless transceiver 13 (again as is well understood in the art). Those skilled in the art will understand and appreciate that the processing platform 11 can comprise a fully or partially programmable platform or can comprise a more hard-wired dedicated purpose fixture as may best accord with the needs and design requirements of a given application. It will also be understood that the functionality of the processing platform 11 can be realized through use of an integrated sole-purpose platform, an integrated multi-purpose platform that supports other functionality, or a distributed multi-platform embodiment where portions of the talker arbitration capability are carried out by various corresponding physically discrete entities. In a similar fashion it will be understood that the memory 12 can comprise a physically distinct entity from the processing platform 11 (as suggested by the illustration) or can comprise an integral part thereof. It will also be understood that the memory 12 can comprise a single element or a distributed entity that subsumes a plurality of physically discrete elements. And, in a similar vein, it will also be appreciated that the memory 12 can be physically disposed proximal to the processing platform 11 or can be located remotely with respect to the processing platform. These and other architectural and configuration options are well understood in the art and require no further elaboration here. So configured, one or more network elements in a given communication system (including multiple dispatch servers and mobile stations themselves) are capable of selectively providing push-to-talk talker arbitration services in support of, for example, push-to-talk communications as conducted amongst members of a given talk group. Referring now to FIG. 2, a process 20 to make effective use of such an apparatus 10 (or any other platform or configuration as may be capable of compliant operation) will be described. This process 20 preferably occurs, at least in substantial part, subsequent to initiation of a push-to-talk talkgroup wireless communication. For example, this process 20 can be usefully processed during a time when one member of a push-to-talk talkgroup is presently allocated an active wireless channel to support a push-to-talk wireless communication to members of their respective talkgroup (for example, a talkgroup comprising two or more mobile stations in accordance with well understood prior art practice). This process 20 automatically considers at least one possible subsequent push-to-talk communication need of the talk group to thereby permit provision of at least one corresponding determination. This consideration can include a wide variety of factors and/or criteria. For example, this consideration can comprise automatically identifying at least one target mobile station to which the present push-to-talk wireless communication is directed. This can comprise a potentially useful consideration because the party to whom a present communication is directed may likely be presumed to then wish to next respond to the present communication. This, in turn, can lead to a corresponding determination that this potential action of the recipient party represents a possible subsequent push-to-talk communication need in that this recipient party may well be a next party to seek allocation of a wireless resource. Other considerations can be taken into account as well, of course. For example, one or more items of context information regarding the talk group may be usefully considered. Examples of potentially useful context information include, but are not limited to: voice recognition results as correspond to analysis of at least a part of a push-to-talk wireless communication (for example, to identify the name of a person to whom the present user is speaking such that this detected name can be correlated against a list of user names and mobile station identifiers to thereby facilitate identification of a likely next speaker); determining which mobile station of the talk group appears to likely comprise a discussion leader (as the discussion leader might be expected to speak more frequently than other participants under at least some circumstances); determining which mobile station of the talk group comprises an originating mobile station as regards the push-to-talk wireless communication; user manipulation of a mobile station (for example, grasping a handset or remote microphone in a particular fashion (as might be detectable using a variety of mechanisms as are presently understood in the art) might be an early indication of an intent to assert the push-to-talk button); push-to-talk wireless communications historical information (where, for example, it might be possible to identify a particular mobile station and/or user that historically tends to communicate more frequently than others of a given talk group); identification of a most frequent initiator of push-to-talk communications (for example, by reference to historic and/or presently accumulated corresponding statistics); geographic location of at least one member of the talk group (as might be ascertainable using global positioning system or other location techniques); and/or a presence or absence of other concurrently used services, to name a few. the type or length of the previous push-to-talk communication (for example, if the previous push-to-talk communication did not contain any audio content or was a so-called call alert, then it may be deemed that the next push-to-talk event is less likely to be from the recipient; the target's current status as being in a meeting or not as inferred, for example, from a calendar meeting schedule for the target; the number of members in the push-to-talk group (for example, when servicing a larger group, it may not be useful to flexibly assign the talker arbitration functionality due to a possibly increased degree of ambiguity regarding accurately identifying a likely next speaker). the RF congestion, frame erasure rate, or link speed achieved (For example, in a group call where mobiles A and B are each equally likely to next assert a push-to-talk, one can break such a tie by placing the talker arbitration functionality at the mobile with the higher data rate and better RF conditions; amongst other benefits this can reduce the amount of system delay that will occur if, instead of A or B, a third mobile next asserts a push-to-talk. This benefit can occur, at least in part, because such a strategy will locate the talker arbitration functionality at a mobile station that has superior communication conditions and that can therefore potentially more quickly respond to another mobile station than, for instance, a mobile station experiencing a lower bit rate link with higher frame erasure rates.). In general, any accessible information that can potentially inform an ability to assess a need for one or more members of a talk group to likely require, in a relatively near-term time frame, a push-to-talk communication resource can comprise an appropriate basis, at least in part, for this consideration. It would also be possible to select or de-select the use of certain consideration criteria as based upon static or dynamic triggers such as time of day, talk group identity, age of available information, and so forth. And, it would also be possible to weight available information (particularly when considering more than one type or source of information) to reflect whatever information may be available regarding a relative sense of importance, trustworthiness, or accuracy. These same kinds of criteria can also be used to influence or control other timing aspects. For example, when the target is deemed to be less likely to next assert a push-to-talk for any such reason, then the talker arbitration functionality may revert from that target mobile station to the dispatch server after a shorter time interval than might otherwise be allotted. As another example, criteria of this type may also be used to impact the timing of how long assignment of the talker arbitration functionality is intentionally delayed; generally this delay may preferably be shorter if the target has a shorter delay before that user becomes aware that the floor is open or has a shorter delay until that user can request the floor. For example, longer playout buffers (which in turn can result from a variety of situations including degraded radio frequency conditions) can result in a longer delay before the target knows the floor is open. The process 20 then automatically identifies 22 a network location to support talker arbitration for the push-to-talk communication needs of the talk group as a function, at least in part, of this corresponding determination. As already noted, this network location can comprise, depending upon the embodiment, one or more infrastructure elements such as a dispatch server and/or a mobile station (including, preferably, one or more mobile stations that comprise a part of the presently supported talk group). For example, upon having previously identified a present communication target for the present push-to-talk communication, this process 20 can facilitate identification of that communication target to subsequently support talker arbitration (specific benefits of such a decision will be discussed in more detail below). Depending upon the embodiment, the process 20 may then optionally pose an intentional delay 23. That is, the process 20 may intentionally delay a subsequent automatic assignment of the talker arbitration function to the identified network location. This delay may be, for example, for a predetermined amount of time or as may be more dynamically ascertained (depending upon the capabilities and needs of a given embodiment). During this period of intentional delay, the process 20 can accommodate other processes if so desired. For example, the process 20 can detect whether one or more specific conditions of interest occur during this period of delay and, when such a condition of interest does occur, automatically re-identifying a (possibly new) network location to support the talker arbitration needs of this talk group. For example, one possible condition of interest is whether a just-previous transmitting mobile station is again immediately seeking to initiate a subsequent push-to-talk wireless communication. Under such circumstances it may be better in some cases to leave the talker arbitration functionality at its present location. Depending upon the embodiment, this process 20 then automatically assigns 24 the identified network location to support talker arbitration for the talk group. Such an assignment can be effected in any of a variety of ways. As one example, at least one explicit message indicating such assignment can be transmitted to the identified network location. As another example, a signal can be transmitted to the identified network location that indicates such assignment in a more implicit manner. For example, the signal might comprise an end-of-transmission signal as would ordinarily be sourced by a concluding mobile station upon concluding its push-to-talk transmission. This end-of-transmission signal might additionally convey to a properly prepared mobile station a triggering message to activate the talker arbitration functionality. Other control strategies and hand-off devices and/or signals can of course be employed as appropriate or desired. Referring now to FIG. 3, a given mobile station process 30 will determine 31 to activate such talker arbitration functionality in response, for example, to receiving at least a first predetermined signal as suggested above (again, such a signal may comprise a signal such as an end-of-transmission signal or a more explicit instruction to activate the talker arbitration capability). In the absence of such an instruction, the mobile station will typically end 32 this consideration for the moment and continue with its ordinary processing. This determination can be repeated as often as may be useful and relevant given the operating circumstances of a given system and the capabilities of a given mobile station as will be well understood by skilled practitioners. When the mobile station does decide to activate the talker arbitration capability, the mobile station activates 33 talker arbitration capability for its talk group. This means that this mobile station will conduct the talker arbitration function for this particular talk group. By appropriate dynamic placement of this function in this way, and as will be illustrated below, it is possible to achieve a considerable reduction in delay times as are ordinarily associated with initiating a push-to-talk wireless communication in such systems. In a preferred embodiment this process 30 will also accommodate deactivation 34 of the talker arbitration capability. This permits the talker arbitration function to again be moved to another network location in accord with the teachings set forth above. Such deactivation can be in response to a wide variety of operational conditions. For example, such deactivation may be programmed to occur automatically at the receipt of a next end-of-transmission signal. As another example, such deactivation may occur upon receipt of a deactivation signal by the mobile station. Referring now to FIG. 4, an illustrative example of a portion of a compliant push-to-talk communication session will be described. This simple example begins with a first mobile station receiving a push-to-talk communication from a second mobile station. During the time 41 that the second mobile station sources this transmission, a dispatch server supporting the communication needs of this small talk group identifies the first mobile station as being the transmission recipient and further identifies the first mobile station as being the next network element to support the talker arbitration function for this talk group. When the second mobile station concludes its transmission, the second mobile station sources an end-of-transmission signal 42 that is received by the dispatch server in accord with well understood prior art practice. Then (perhaps following an optional period of delay 43 as described above to more readily and efficiently accommodate, for example, a relatively near-term fresh push-to-talk transmission need of the second mobile station), the dispatch server transmits to the first mobile station a talker arbitration transfer signal 44 such as those described above. Upon receipt of this talker arbitration transfer signal 44, and as described above, the first mobile station activates its talker arbitration capability. The first mobile station also provides an end-of-transmission indicator 45 to the user of the first mobile station (for example, many such mobile stations provide a distinctive audible sound to indicate that the previously transmitting party has concluded their transmission). Upon detecting that the user has asserted the push-to-talk button 46, the first mobile station begins its channel acquisition/talk permission process. This includes provision of a corresponding talk request to the talker arbitrator in accord with ordinary practice. In this example, however, the talker arbitration function is presently supported by the first mobile station. As a result, the talker arbitrator can receive and respond to the talk request of the first mobile station in considerably less time than would ordinarily be experienced. For example, rather than requiring upwards of 700 milliseconds to effect this process, a “talk” indicator 47 can be provided to the user virtually immediately as the overall arbitration process will now, in such an example, likely require less than 100 milliseconds. The user of the first mobile station can then use the allocated communication resource/permission to support the desired audio transmission 48 in ordinary course. When assigning the talker arbitration function as described above, of course, the system will typically not know with certainty the identity of a next user of the push-to-talk communication resource. For example, in the illustrative scenario just described, the second mobile station (or another mobile station in the talk group other than the first mobile station) may be the next mobile station to seek transmission resources. When this occurs, and with continuing reference to the scenario just described, the first mobile station will simply effect the talker arbitration function for the requesting mobile station. To illustrate, and referring now to FIG. 5, the second mobile station may be the first station to experience a push-to-talk button assertion 51 by its respective user. The second mobile station will then issue a talk request 51A to the dispatch server. The latter, in turn, can perform a look-up 52 in an appropriate memory resource to identify the present location of the talker arbitrator (as a less preferred alternative, the dispatch server could poll the mobile stations of the talk group to identify the present talker arbitrator). In this example, the dispatch server would therefore identify the first mobile station as the present talker arbitrator. Accordingly, the dispatch server will forward the talk request 51B to the first mobile station. The first mobile station will then process 53 that talk request in accordance with its talker arbitration programming and capability. In this example, there are no earlier or otherwise competing talk requests and therefore the talker arbitration platform (i.e., the first mobile station) will issue a grant 54A that the dispatch server forwards 54B to the second mobile station. The latter then transmits its audio information 55 to the first mobile station and, upon concluding that transmission, sources an end-of-transmission signal 56A that the dispatch server will again forward 56B to the first mobile station. So configured, it can be seen that flexibly locating, and even dynamically locating, the talker arbitrator functionality for a talk group need not unduly impair unexpected communication needs. More particularly, actual communication needs that conflict with the presumptions that underlie flexible placement of the talker arbitration functionality are nevertheless still processed and supported in an effective manner. At some point, it will typically be desired or appropriate to relocate the talker arbitration functionality from such an assigned mobile station. With reference to FIG. 6, and as otherwise noted above, a deactivation signal 61 of appropriate nature and/or a predetermined window 62 of activity (or inactivity) can be used to effect a transfer 63 of the talker arbitration function away the mobile station. For example, the mobile station can transmit a message to signal deactivation of the talker arbitration function and/or to transmit the enabling programming itself to, for example, a dispatch server. As another example (not illustrated), the first mobile station could transmit a message to signal a hand-off of the talker arbitration function to another location such as another mobile station. These examples and scenarios are intended to be illustrative only and are not intended to constitute an exhaustive listing of the many various way in which flexible positioning of a talker arbitration capability with respect to the members of a given talk group and/or the infrastructure elements that support or facilitate the communications of such a talk group can be accomplished in accord with these teachings. Those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described embodiments without departing from the spirit and scope of the invention, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept. For example, when multiple dispatch servers support different arbitration methods towards their served mobile stations, such that when a mobile station served by a given server has the floor it will use this indigenous method of floor control, this might present a problem for a foreign mobile station that expects to use a different floor control methodology. In such a situation, when a mobile station being presently served by a foreign server has control and this same mobile station makes a floor control request, its server can be configured and arranged to translate the floor control method to the appropriate floor control method and relay the translated request to the foreign server for arbitration as is otherwise described above. It will also be understood by those skilled in the art that these teachings are generally applicable to other forms of communication where floor-control-like mechanisms are employed, such as: push to video calls (where video content substitutes for audio content in the descriptions above); push-to-see or photo calls (where one is transmitting images or some other data file instead of voice); telephone interconnect full-duplex voice calls (where one is providing a method to more rapidly establish a full-duplex voice call between users; in a case such as this, flexible location of the floor control functionality would likely not be required upon establishment of the full-duplex link); text messaging or text chat where floor control mechanisms are often of critical importance. | <SOH> BACKGROUND <EOH>Push-to-talk styled communications are well known in the art. The members of a talkgroup comprising two or more wireless mobile stations are able to wirelessly communicate with one another by simply asserting a push-to-talk button. In many communication systems, assertion of the push-to-talk button does not immediately permit the user to begin talking (and/or transmitting). Instead, assertion of the push-to-talk button initiates a sequence of events whereby the mobile station requests and/or otherwise acquires a communication resource (such as a specific transmission frequency, time slot(s), and/or a spreading code, to name a few) to facilitate the desired communication. In such systems, a specific audible signal will usually be provided to the user when, subsequent to assertion of the push-to-talk button, the mobile station in fact is prepared to at least record and then, usually, to shortly later transmit the user's message. The duration of delay between when the user first asserts the push-to-talk button and when the user receives the signal indicating that the speech may now commence can vary for a variety of reasons. This delay, however, often becomes an obvious and highly visible measure of quality of service for many users. In general, the shorter the delay, the higher the perception of service quality. In some cases this delay occurs due to circumstances beyond immediate control (for example, high system loading or infrastructure downtime can adversely impact system performance in this regard). In many instances, however, this delay cannot be reasonably reduced below a minimal duration that is nevertheless a source of disappointment to at least some users. Talker arbitration requirements comprise one such example. Talker arbitration facilitates a decision process whereby the communication system responds to a push-to-talk talk request by ascertaining whether any higher priority (and/or earlier) talk request presents a conflict and arbitrates such a conflict through selection of only one of the requesting parties. A dispatch server usually supports the talker arbitration service in most such systems. Even when only a single wireless station presently seeks to communicate (i.e., when there is no present conflict) the wireless station must still transmit its intentions to the talker arbitrator at the dispatch server, and the talker arbitrator must still conclude the talker arbitration process and communicate its communication grant (or approval) to the requesting wireless station. This overall process can easily consume 700 milliseconds (or more) even under relatively ideal operating conditions in many systems. This minimal delay floor can lead to a sense of dissatisfaction with respect to the operation and efficiency of the wireless station and/or the communication system. | <SOH> BRIEF DESCRIPTION OF THE DRAWINGS <EOH>The above needs are at least partially met through the provisioning of the talker arbitration method and apparatus described in the following detailed description, particularly when studied in conjunction with the drawings, wherein: FIG. 1 comprises a block diagram as configured in accordance with various embodiments of the invention; FIG. 2 comprises a flow diagram as configured in accordance with various embodiments of the invention; FIG. 3 comprises a flow diagram as configured in accordance with various embodiments of the invention; FIG. 4 comprises a signal flow diagram as configured in accordance with various embodiments of the invention; FIG. 5 comprises a signal flow diagram as configured in accordance with various embodiments of the invention; and FIG. 6 comprises a signal flow diagram as configured in accordance with various embodiments of the invention. detailed-description description="Detailed Description" end="lead"? Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or placement of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will also be understood that the terms and expressions used herein have the ordinary meaning as is usually accorded to such terms and expressions by those skilled in the corresponding respective areas of inquiry and study except where other specific meanings have otherwise been set forth herein. | 20040408 | 20090707 | 20051013 | 61619.0 | 0 | LEE, JOHN J | TALKER ARBITRATION METHOD AND APPARATUS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,820,740 | ACCEPTED | Direct backlight module | A direct backlight module for an LCD panel includes a base, a supporter plate and a plurality of films. The base further has a plurality of lamps parallel arranged thereinside. The supporter plate is mounted over the base and further has a frame and a plurality of wires. The frame is a square structure having a central opening, and each of the wires is constructed at the frame by crossing the central opening. The films are mounted layer by layer over the supporter plate and born by both the frame and the wires. The module can engage with an LCD at a side exposing the film and, under such an engagement, lights of the lamps can pass through the central opening of the supporter plate, penetrate the films, and finally reach the LCD. | 1. A direct backlight module, comprising: a base, having a plurality of parallel-arranged lamps; a supporter plate, mounted over the base, further having a frame and a plurality of wires, in which the frame is a square structure having a central opening, in which each of the wires is constructed at the frame and crosses the central opening; and a plurality of films, mounted over and born by the supporter plate; 2. The direct backlight module according to claim 1, wherein said lamp is a Cold Cathode Fluorescent Lamp. 3. The direct backlight module according to claim 1, wherein said wires are parallel arranged over said central opening of said supporter plate. 4. The direct backlight module according to claim 1, wherein said wires are cross arranged over said central opening of said supporter plate. 5. The direct backlight module according to claim 1, wherein materials to form said wires comprise metals. 6. The direct backlight module according to claim 1, wherein materials to form said wires comprise polymers. 7. The direct backlight module according to claim 1, wherein said films include a film to diffuse said lights. 8. The direct backlight module according to claim 1, wherein said films include a film to achieve a haze effect. 9. The direct backlight module according to claim 1, wherein said base has at least an interior bottom surface thereof coated with a reflection material. 10. The direct backlight module according to claim 1, comprises a reflection plate formed on at least one interior surface of said base. | BACKGROUND OF THE INVENTION (1) Field of the Invention The invention relates to a direct backlight module, and more particularly to a backlight module that can provide a backlight source to a liquid crystal display. (2) Description of the Prior Art With rapid development of thin film transistor (TFT) technology, especially in light weight, energy saving and non-radiation features, the liquid crystal display (LCD) has been widely used in various electronic devices such as personal digital assistants (PDA), notebook computers, digital cameras, slim televisions, mobile phones, and so on. In contrast to conventional cathode radiation devices, the liquid crystal display is benefited from a light source of a backlight module to make clear the information tossed to the display. Referring to FIG. 1A and FIG. 1B, an exploded view of a typical LCD panel including a conventional direct backlight module and a cross-sectional view of the conventional direct backlight module are shown, respectively. As illustrated, the backlight module 1 located under an LCD 2 includes a base 10, a diffuser plate 11 and a plurality of films 12. In the base 10, a plurality of parallel lamps 13 are mounted. In the space formed between the lamps 13 and the interior bottom of the base 1, a common reflection plate 14 for reflection lights of the lamps 13 is included. The diffuser plate 11 located over the lamps 13 is typically a white light-permeable acrylic or polycarbonate plate to diffuse and so homogenize the lights provided by the lamps 13. The films 12 including multiple sheets and layered on the diffuser plate 11 are introduced to perform specific optical purposes. For example, the prism sheet is used to cluster lights, and the brightness-enhancement sheet is used to enhance the brightness of the LCD 2. Further, the films 12 can also have a diffuser sheet. In practice, the determination upon layers and sorts of the films 12 for a particular LCD panel is a designer option. Ideally, the lights generated by the lamps 13 after passing the diffuser plate 11 and the films 12 are homogenized and thus can serve as a perfect backlight source to the LCD 2. Also shown in FIG. 1A, the LCD 2 is mounted over the films 12 of the base 1. A bezel 3 is further mounted on top of the LCD 2 and engaged with the base 10 to complete the assembly of the LCD panel. Nevertheless, the conventional direct backlight module 1 described above still has the following disadvantages. a. The weight of the conventional backlight module is a negative factor to the LCD panel. As known, the diffuser plate in the art is usually made of acrylic, PC or glass material with a 2-4 mm thickness. Such a thickness will definitely become an awkward design as the dimension of the LCD panel becomes larger and larger. b. The acrylic material of the diffuser plate is vulnerable to deform after a substantial period of exposure time under the lamps, from which the backlight quality is easy to be distorted. c. The PC board for the diffuser plate will be gradually yellowed by the UV ray from the lamps, and thereby the backlight quality will definitely influenced. d. The overall thickness of the direct backlight module including the diffuser plate and the lamps is too big to make the LCD panel slimmer. Therefore, a light-weight, thin and quality direct backlight module is always a topic to which the skill in the art is willing to devote. SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a direct backlight module which has a better backlight source. It is another object of the present invention to provide a light-weight direct backlight module. It is a further object of the present invention to provide a slimmer direct backlight module. The direct backlight module in accordance with the present invention for performing as a backlight source to the LCD panel includes a base, a supporter plate and a plurality of films. In an interior of the base, a plurality of parallel lamps are mounted and a reflection plate for reflecting lights of the lamp is formed on at least one interior surface of the base. The supporter plate includes a frame and a plurality of interior wires. The frame located above the base is consisted of four lateral sides and provides an opening to pass the light. Each of the wires is used to bridge two lateral sides over the opening. The arrangement of the wires can be a parallel pattern, a cross pattern or the like. In addition, the wire, made of a metal or a plastic, is preferred to be in a tension state in the frame. The films are layered over and thus supported by the supporter plate. In assembling the LCD panel, the backlight module including, in order from top to bottom, the films, the supporter plate, the lamps, the reflection plate and the base as a compact module is engaged with the LCD and a bezel is further applied to the LCD for assuring the assembly of the LCD and the backlight module by matching with the base. Upon such an arrangement, lights of the lamps can pass the opening of the supporter plate and the films and finally reach the LCD. In the present invention, the wire of the supporter plate preferably has a diameter below 0.5 mm. Compared to the diffuser plate in the conventional LCD panel, the supporter plate of the present invention formed by a frame and cross wires does provide a light-weight and slim alternative. For the direct backlight module does not have the diffuser plate, thus the problems in distortion and yellowness will never occur. In the present invention, one of the films can be a diffuser film with a predetermined haze rate to achieve a substantial degree of diffusing effect that is originally provided by the conventional diffuser plate. All these objects are achieved by the direct backlight module described below. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be specified with reference to its preferred embodiment illustrated in the drawings, in which FIG. 1A is an exploded perspective view of a typical LCD panel with a conventional direct backlight module; FIG. 1B is a cross-sectional view of the direct backlight module of FIG. 1A; FIG. 2A is an exploded perspective view of an LCD panel with a preferred direct backlight module in accordance with the present invention; FIG. 2B is a cross-sectional view of the direct backlight module of FIG. 2A; and FIG. 3 is a perspective view of another preferred supporter plate in accordance with the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENT The invention disclosed herein is directed to a direct backlight module. In the following description, numerous details are set forth in order to provide a thorough understanding of the present invention. It will be appreciated by one skilled in the art that variations of these specific details are possible while still achieving the results of the present invention. In other instance, well-known components are not described in detail in order not to unnecessarily obscure the present invention. Referring now to FIG. 2A and FIG. 2B, an exploded view of a typical LCD panel with a preferred direct backlight module 4 of the present invention and a cross-sectional view of the preferred direct backlight module 4 are shown, respectively. As shown, the direct backlight module 4 for providing a backlight source is located under an LCD 2 and includes a base 40, a supporter plate 41 and a plurality of films 42. The base 40 further includes interiorly a plurality of parallel lamps 401. The lamp 401 can be a Cold Cathode Fluorescent Lamp or the like. Also, at least a reflection plate 402 can be constructed between an interior bottom surface of the base 40 and the lamps 401 or formed on at least one interior surface of the base 40 so as to reflect lights of the lamps 401 and direct the reflected lights toward the LCD 2. Alternatively, the reflection plate 402 can be formed as a reflection material coated on the interior bottom surface of the base 40. The supporter plate 41 placed upon the base 40 includes a frame 411 and a plurality of wires 412 constructed inside the frame 411. the frame 411 can be a square structure having a central opening to pass the lights. Each of the wires 412 is constructed to bridge any two lateral sides of the frame 411 and to cross the central opening of the frame 411. In the invention, the wires 412 can be arranged to be a parallel pattern as shown in FIG. 2A, a cross pattern as shown in FIG. 3, or any other proper pattern. Materials for the wires 411 can be metals, polymers or the like. The wire 411 is preferable to have a diameter less than 0.5 mm and is pre-tensed good to bear the films 42. The films 42 of the present invention can include a prism film, a film to diffuse lights, a film to achieve a haze effect, a color-filtering film, a depolarizing film, or any other proper film to meet a design purpose. Those films 42 are stacked layer by layer over the supporter plate 41. After the base 40 including the lamps 401 and the reflection plate 402, the supporter plate 41 and the films 42 are integrated to form a compact direct backlight module 4, the module 4 can then engage with the LCD 2 at a side exposing the film 42, and the engagement can then be ensured by having a bezel 3 to frame the LCD 2 and be fastened to the base 40. Upon such an arrangement, lights of the lamps 401 can pass through the central opening of the supporter plate 41, penetrate the films 42, and finally reach the LCD 2. It should be noted again that the major effort of the present invention is to introduce the supporter plate 41 for bearing the films 42. Contrary to the conventional diffuser plate 11 shown in FIG. 1B, the supporter plate 41 of the present invention is more lightweight, contributed by the inclusion of the wires 412 having diameters less than 0.5 mm. As a result, the direct backlight module 4 of the present invention is much lighter. By waiving the diffuser plate, the present invention won't encounter the distortion or yellowness problem. Nevertheless, though the light-diffusing performance in the present invention may be sacrificed to a substantial degree by ridding the diffuser plate, yet it can still be regained by adding a diffuser film with a predetermined haze rate to achieve a satisfied degree of diffusing effect. Thus, the image quality of the LCD in the present invention can be ensured. While the present invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be without departing from the spirit and scope of the present invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>(1) Field of the Invention The invention relates to a direct backlight module, and more particularly to a backlight module that can provide a backlight source to a liquid crystal display. (2) Description of the Prior Art With rapid development of thin film transistor (TFT) technology, especially in light weight, energy saving and non-radiation features, the liquid crystal display (LCD) has been widely used in various electronic devices such as personal digital assistants (PDA), notebook computers, digital cameras, slim televisions, mobile phones, and so on. In contrast to conventional cathode radiation devices, the liquid crystal display is benefited from a light source of a backlight module to make clear the information tossed to the display. Referring to FIG. 1A and FIG. 1B , an exploded view of a typical LCD panel including a conventional direct backlight module and a cross-sectional view of the conventional direct backlight module are shown, respectively. As illustrated, the backlight module 1 located under an LCD 2 includes a base 10 , a diffuser plate 11 and a plurality of films 12 . In the base 10 , a plurality of parallel lamps 13 are mounted. In the space formed between the lamps 13 and the interior bottom of the base 1 , a common reflection plate 14 for reflection lights of the lamps 13 is included. The diffuser plate 11 located over the lamps 13 is typically a white light-permeable acrylic or polycarbonate plate to diffuse and so homogenize the lights provided by the lamps 13 . The films 12 including multiple sheets and layered on the diffuser plate 11 are introduced to perform specific optical purposes. For example, the prism sheet is used to cluster lights, and the brightness-enhancement sheet is used to enhance the brightness of the LCD 2 . Further, the films 12 can also have a diffuser sheet. In practice, the determination upon layers and sorts of the films 12 for a particular LCD panel is a designer option. Ideally, the lights generated by the lamps 13 after passing the diffuser plate 11 and the films 12 are homogenized and thus can serve as a perfect backlight source to the LCD 2 . Also shown in FIG. 1A , the LCD 2 is mounted over the films 12 of the base 1 . A bezel 3 is further mounted on top of the LCD 2 and engaged with the base 10 to complete the assembly of the LCD panel. Nevertheless, the conventional direct backlight module 1 described above still has the following disadvantages. a. The weight of the conventional backlight module is a negative factor to the LCD panel. As known, the diffuser plate in the art is usually made of acrylic, PC or glass material with a 2-4 mm thickness. Such a thickness will definitely become an awkward design as the dimension of the LCD panel becomes larger and larger. b. The acrylic material of the diffuser plate is vulnerable to deform after a substantial period of exposure time under the lamps, from which the backlight quality is easy to be distorted. c. The PC board for the diffuser plate will be gradually yellowed by the UV ray from the lamps, and thereby the backlight quality will definitely influenced. d. The overall thickness of the direct backlight module including the diffuser plate and the lamps is too big to make the LCD panel slimmer. Therefore, a light-weight, thin and quality direct backlight module is always a topic to which the skill in the art is willing to devote. | <SOH> SUMMARY OF THE INVENTION <EOH>Accordingly, it is a primary object of the present invention to provide a direct backlight module which has a better backlight source. It is another object of the present invention to provide a light-weight direct backlight module. It is a further object of the present invention to provide a slimmer direct backlight module. The direct backlight module in accordance with the present invention for performing as a backlight source to the LCD panel includes a base, a supporter plate and a plurality of films. In an interior of the base, a plurality of parallel lamps are mounted and a reflection plate for reflecting lights of the lamp is formed on at least one interior surface of the base. The supporter plate includes a frame and a plurality of interior wires. The frame located above the base is consisted of four lateral sides and provides an opening to pass the light. Each of the wires is used to bridge two lateral sides over the opening. The arrangement of the wires can be a parallel pattern, a cross pattern or the like. In addition, the wire, made of a metal or a plastic, is preferred to be in a tension state in the frame. The films are layered over and thus supported by the supporter plate. In assembling the LCD panel, the backlight module including, in order from top to bottom, the films, the supporter plate, the lamps, the reflection plate and the base as a compact module is engaged with the LCD and a bezel is further applied to the LCD for assuring the assembly of the LCD and the backlight module by matching with the base. Upon such an arrangement, lights of the lamps can pass the opening of the supporter plate and the films and finally reach the LCD. In the present invention, the wire of the supporter plate preferably has a diameter below 0.5 mm. Compared to the diffuser plate in the conventional LCD panel, the supporter plate of the present invention formed by a frame and cross wires does provide a light-weight and slim alternative. For the direct backlight module does not have the diffuser plate, thus the problems in distortion and yellowness will never occur. In the present invention, one of the films can be a diffuser film with a predetermined haze rate to achieve a substantial degree of diffusing effect that is originally provided by the conventional diffuser plate. All these objects are achieved by the direct backlight module described below. | 20040409 | 20061017 | 20050811 | 97070.0 | 0 | CARIASO, ALAN B | DIRECT BACKLIGHT MODULE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,820,920 | ACCEPTED | Method and apparatus for indication of a charging condition | The invention concerns an apparatus (100) for indication of a charging condition. The apparatus includes an indication circuit (126) having at least one electromagnet (120) and a charge control circuit (128) for controlling charging current to a portable device (110). The indication circuit causes the apparatus to electromagnetically engage the portable device and the charge control circuit provides charging current to the portable device during the engagement. The indication circuit also causes the apparatus to electromagnetically decouple the portable device when the portable device is charged to a predetermined level to permit a user to remove the portable device from the apparatus. | 1. An apparatus for indication of a charging condition, comprising: an indication circuit having at least one electromagnet; and a charge control circuit for controlling charging current to a portable device; wherein the indication circuit causes the apparatus to electromagnetically engage the portable device and the charge control circuit provides charging current to the portable device during the engagement and wherein the indication circuit causes the apparatus to electromagnetically decouple the portable device when the portable device is charged to a predetermined level to permit a user to remove the portable device from the apparatus. 2. The apparatus according to claim 1, wherein the apparatus further comprises at least one contact and wherein the apparatus contact electrically couples to a contact of the portable device when the apparatus electromagnetically engages the portable device. 3. The apparatus according to claim 1, wherein the indication circuit provides an engaging current to the electromagnet, wherein the engaging current causes the electromagnet to generate at least one of an attractive magnetic field and a repulsive magnetic field. 4. The apparatus according to claim 3, wherein when the electromagnet generates an attractive magnetic field, the electromagnet attracts at least one of a non-magnetized, metallic component of the portable device and an opposite pole magnet of the portable device. 5. The apparatus according to claim 3, wherein when the electromagnet generates a repulsive magnetic field, the electromagnet repels a like pole magnet of the portable device. 6. The apparatus according to claim 2, wherein the electromagnet and the contacts are positioned on a first surface of the apparatus. 7. The apparatus according to claim 2, wherein the electromagnet is positioned on a first surface of the apparatus and the contacts are positioned on a second surface of the apparatus, wherein the second surface opposes the first surface. 8. The apparatus according to claim 1, wherein the electromagnet generates a magnetic field when the apparatus electromagnetically engages the portable device and the magnetic field decreases in strength as the portable device is charged towards the predetermined level. 9. The apparatus according to claim 8, wherein the indication circuit and the charge control circuit are in series. 10. The apparatus according to claim 1, wherein the electromagnet generates a magnetic field when the apparatus electromagnetically engages the portable device and the magnetic field remains at a substantially fixed level as the portable device is charged towards the predetermined level. 11. The apparatus according to claim 10, wherein the indication circuit and the charge control circuit are in parallel. 12. The apparatus according to claim 1, wherein the apparatus further comprises a sensor for determining whether the portable device has been removed from the apparatus. 13. An apparatus for indication of a charging condition, comprising: an indication circuit having at least one electromagnet; and a charge control circuit for controlling charging current to a portable device; wherein the indication circuit causes the apparatus to electromagnetically engage the portable device in a first position and the charge control circuit provides charging current to the portable device during the first position engagement and wherein the indication circuit causes the apparatus to electromagnetically engage the portable device in a second position when the portable device is charged to a predetermined level such that a user is permitted to remove the portable device from the apparatus. 14. A portable device, comprising: at least one contact for electrically coupling to at least one corresponding contact on a charging unit; and a magnetically susceptible component; wherein the charging unit electromagnetically engages the magnetically susceptible component and provides a charging current to the portable device through the contacts of the portable device and the corresponding contacts of the charging unit during the engagement; wherein the charging unit electromagnetically decouples the portable device when the portable device is charged to a predetermined level to permit a user to remove the portable device from the charging unit. 15. The portable device according to claim 14, wherein the magnetically susceptible component is at least one of a non-magnetized, metallic component and a magnet. 16. The portable device according to claim 15, wherein the magnet of the portable device is a like pole magnet with respect to an electromagnet in the charging unit such that the electromagnet generates a repulsive magnetic field when the charging unit electromagnetically engages the portable device. 17. A method for indication of a charging condition, comprising the steps of: electromagnetically engaging a portable device to a charging unit such that the portable device is magnetically urged towards and secured to at least a portion of the charging unit; supplying charging current to the portable device; and when the portable device is charged to a predetermined level, electromagnetically decoupling the portable device from the charging unit to permit a user to remove the portable device from the charging unit. 18. The method according to claim 17, further comprising the steps of: providing an engaging current to at least one electromagnet of the charging unit, wherein the providing an engaging current step causes the electromagnet to generate at least one of an attractive magnetic field and a repulsive magnetic field. 19. The method according to claim 17, wherein the charging unit has at least one electromagnet and the method further comprises the steps of: generating a magnetic field during the electromagnetically engaging step; and decreasing the strength of the magnetic field as the portable device is charged towards the predetermined level. 20. The method according to claim 17, wherein the charging unit has at least one electromagnet and the method further comprises the steps of: generating a magnetic field during the electromagnetically engaging step; and keeping the strength of the magnetic field at a substantially constant level as the portable device is charged towards the predetermined level. 21. The method according to claim 17, further comprising the steps of; determining whether the portable device has been removed from the charging unit; and in response to the portable device being removed from the charging unit, setting the charging unit to a predetermined charging configuration. 22. The method according to claim 17, wherein the electromagnetically engaging step comprises magnetically urging and securing the portable device to the charging unit with an attractive magnetic field and the electromagnetically decoupling step comprises removing the attractive magnetic field. 23. The method according to claim 17, wherein the electromagnetically engaging step comprises magnetically urging and securing the portable device to the charging unit with a repulsive magnetic field and the electromagnetically decoupling step comprises removing the repulsive magnetic field. 24. A method for indication of a charging condition, comprising the steps of: electromagnetically engaging a portable device to a charging unit in a first position such that the portable device is magnetically urged towards and secured to at least a first portion of the charging unit; supplying charging current to the portable device; and when the portable device is charged to a predetermined level, electromagnetically engaging the portable device to the charging unit in a second position such that the portable device is magnetically urged towards and secured to a second portion of the charging unit, wherein when the portable device is in the second position, a user is permitted to remove the portable device from the charging unit. | BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to energy management and more particularly to methods for charging batteries. 2. Description of the Related Art Portable electronic devices, such as cellular telephones and personal digital assistants, have become very popular in today's marketplace. Virtually all of these devices receive their power from a portable, rechargeable battery. For some models, the portable electronic device is coupled to a charging unit, such as a desktop charger, to allow the battery of the portable electronic device to be recharged. Presently, when a battery is fully charged, there are several visual indicators that may be employed to provide notice to a user that the battery is ready for use. For example, many portable electronic devices, such as cellular telephones, display a message that indicates that the charging process is complete. Alternatively, some of the charging units are equipped with a light emitting diode (LED) to signal when the battery is charged to capacity. Such indicators may be useful to many users; however, some users may suffer from poor or impaired vision, which may prevent them from determining when the portable electronic device is ready for use. SUMMARY OF THE INVENTION The present invention concerns an apparatus for indication of a charging condition. The apparatus includes an indication circuit having at least one electromagnet and a charge control circuit for controlling charging current to a portable device. The indication circuit causes the apparatus to electromagnetically engage the portable device, and the charge control circuit provides charging current to the portable device during the engagement. In addition, the indication circuit causes the apparatus to electromagnetically decouple the portable device when the portable device is charged to a predetermined level to permit a user to remove the portable device from the apparatus. The apparatus can also include at least one contact. The apparatus contact can electrically couple to a contact of the portable device when the apparatus electromagnetically engages the portable device. In one arrangement, the indication circuit can provide an engaging current to the electromagnet. The engaging current can cause the electromagnet to generate at least one of an attractive magnetic field and a repulsive magnetic field. As an example, when the electromagnet generates an attractive magnetic field, the electromagnet can attract at least one of a non-magnetized, metallic component of the portable device and an opposite pole magnet of the portable device. Alternatively, when the electromagnet generates a repulsive magnetic field, the electromagnet can repel a like pole magnet of the portable device. In another arrangement, the electromagnet and the contacts can be positioned on a first surface of the apparatus. Also, the electromagnet can be positioned on a first surface of the apparatus, and the contacts can be positioned on a second surface of the apparatus in which the second surface can oppose the first surface. In one embodiment of the invention, the electromagnet can generate a magnetic field when the apparatus electromagnetically engages the portable device, and the magnetic field can decrease in strength as the portable device is charged towards the predetermined level. As an example, the indication circuit and the charge control circuit can be in series. In another embodiment, the electromagnet can generate a magnetic field when the apparatus electromagnetically engages the portable device, and the magnetic field can remain at a substantially fixed level as the portable device is charged towards the predetermined level. In this arrangement, the indication circuit and the charge control circuit can be in parallel. The apparatus can also include a sensor for determining whether the portable device has been removed from the apparatus. The present invention also concerns another apparatus for indication of a charging condition. The apparatus can include an indication circuit having at least one electromagnet and a charge control circuit for controlling charging current to a portable device. The indication circuit causes the apparatus to electromagnetically engage the portable device in a first position, and the charge control circuit can provide charging current to the portable device during the first position engagement. The indication circuit causes the apparatus to electromagnetically engage the portable device in a second position when the portable device is charged to a predetermined level such that the charge control circuit stops providing charging current to the portable device and a user is permitted to remove the portable device from the apparatus. The present invention also concerns a portable device. The portable device includes at least one contact for electrically coupling to at least one corresponding contact on a charging unit and a magnetically susceptible component. The charging unit electromagnetically engages the magnetically susceptible component and provides a charging current to the portable device through the contacts of the portable device and the corresponding contacts of the charging unit during the engagement. In addition, the charging unit electromagnetically decouples the portable device when the portable device is charged to a predetermined level to permit a user to remove the portable device from the charging unit. In one arrangement, the magnetically susceptible component can be a non-magnetized, metallic component or a magnet. As an example, the magnet of the portable device can be a like pole magnet with respect to an electromagnet in the charging unit such that the electromagnet can generate a repulsive magnetic field when the charging unit electromagnetically engages the portable device. The present invention also concerns a method for indication of a charging condition. The method can include the steps of electromagnetically engaging a portable device to a charging unit such that the portable device is magnetically urged towards and secured to at least a portion of the charging unit, supplying charging current to the portable device and when the portable device is charged to a predetermined level, electromagnetically decoupling the portable device from the charging unit to permit a user to remove the portable device from the charging unit. The method can also include the steps of providing an engaging current to at least one electromagnet of the charging unit. This step can cause the electromagnet to generate at least one of an attractive magnetic field and a repulsive magnetic field. Further, the charging unit can have at least one electromagnet, and the method can also include the steps of generating a magnetic field during the electromagnetically engaging step and decreasing the strength of the magnetic field as the portable device is charged towards the predetermined level. As an alternative, the method can further include the step of keeping the strength of the magnetic field at a substantially constant level as the portable device is charged towards the predetermined level. In one arrangement, the method can include the steps of determining whether the portable device has been removed from the charging unit and in response to the portable device being removed from the charging unit, setting the charging unit to a predetermined charging configuration. In another arrangement, the electromagnetically engaging step can include magnetically urging and securing the portable device to the charging unit with an attractive magnetic field, and the electromagnetically decoupling step can include removing the attractive magnetic field. Alternatively, the electromagnetically engaging step can include magnetically urging and securing the portable device to the charging unit with a repulsive magnetic field, and the electromagnetically decoupling step can include removing the repulsive magnetic field. The present invention also concerns another method for indication of a charging condition. The method includes the steps of electromagnetically engaging a portable device to a charging unit in a first position such that the portable device is magnetically urged towards and secured to at least a first portion of the charging unit, supplying charging current to the portable device and when the portable device is charged to a predetermined level, electromagnetically engaging the portable device to the charging unit in a second position such that the portable device is magnetically urged towards and secured to a second portion of the charging unit. When the portable device is in the second position, the charging current is stopped, and a user is permitted to remove the portable device from the charging unit. BRIEF DESCRIPTION OF THE DRAWINGS The features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify like elements, and in which: FIG. 1 illustrates a portable device and a charging apparatus in accordance with an embodiment of the inventive arrangements; FIG. 2 illustrates a front-sectional view of a portion of the portable device and the charging apparatus of FIG. 1 in which the portable device is coupled to the charging apparatus in accordance with an embodiment of the inventive arrangements; FIG. 3 illustrates a schematic for a charging apparatus and a portable device in accordance with an embodiment of the inventive arrangements; FIG. 4 illustrates another schematic for a charging apparatus and a portable device in accordance with an embodiment of the inventive arrangements; FIG. 5 illustrates another portable device and charging apparatus in accordance with an embodiment of the inventive arrangements; FIG. 6 illustrates a front-sectional view of a portion of the portable device and the charging apparatus of FIG. 5 in which the portable device is coupled to the charging apparatus in accordance with an embodiment of the inventive arrangements; FIG. 7 illustrates yet another portable device and charging apparatus in accordance with an embodiment of the inventive arrangements; FIG. 8 illustrates a front-sectional view of a portion of the portable device and the charging apparatus of FIG. 7 in which the portable device is coupled to the charging apparatus in a first position in accordance with an embodiment of the inventive arrangements; FIG. 9 illustrates a front-sectional view of a portion of the portable device and the charging apparatus of FIG. 7 in which the portable device is coupled to the charging apparatus in a second position in accordance with an embodiment of the inventive arrangements; FIG. 10 illustrates another schematic for a charging apparatus and a portable device in accordance with an embodiment of the inventive arrangements; FIG. 11 illustrates yet another schematic for a charging apparatus and a portable device in accordance with an embodiment of the inventive arrangements; FIG. 12 illustrates a method for indication of a charging condition in accordance with an embodiment of the inventive arrangements; and FIG. 13 illustrates another method for indication of a charging condition in accordance with an embodiment of the inventive arrangements. DETAILED DESCRIPTION While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward. As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention. The terms a or an, as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language). The term coupled, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. The terms program, software application, and the like as used herein, are defined as a sequence of instructions designed for execution on a computer system. A program, computer program, or software application may include a subroutine, a function, a procedure, an object method, an object implementation, an executable application, an applet, a servlet, a source code, an object code, a shared library/dynamic load library and/or other sequence of instructions designed for execution on a computer system. Referring to FIG. 1, an apparatus 100 for indication of a charging condition is shown. In one embodiment of the invention, the apparatus 100 can be a charging unit for charging a portable device 110, such as a cellular telephone. When the portable device 110 is coupled to the apparatus 100, the apparatus 100 can provide charging current to the portable device 110. The apparatus 100 is not limited to charging cellular telephones, however, as the apparatus 100 can be used to charge any portable unit capable of receiving a charging current. As is known in the art, the apparatus 100 can be used to charge the portable device 110 to a predetermined level, such as a fully-charged level, as determined by the specifications of the portable device 110. In one arrangement, the apparatus 100 can have a base 112 that can include a cavity 114 for receiving the portable device 110. The apparatus 100 can also include a first surface 116, on which one or more contacts 118 and one or more electromagnets 120 may be positioned. In addition, the portable device 110 may include one or more corresponding contacts 122 and one or more magnetically susceptible components 124. For purposes of the invention, a magnetically susceptible component can be any material that may be attracted or repelled by a magnetic field generated by the electromagnet 120. As an example, the magnetically susceptible component 124 can be a non-magnetized metal or a magnet. When the portable device 110 is coupled to the apparatus 100, the contacts 118 of the apparatus 100 can engage the contacts 122 of the portable unit 110, which can enable the apparatus 100 to provide a charging current to the portable unit 110. In this example, the electromagnet 120 can generate a magnetic field that can attract the magnetically susceptible component 124 of the portable device 110. Here, the magnetically susceptible component 124 can be a non-magnetized metal or an opposite pole magnet as compared to the generated magnetic field. This attraction can help secure the portable device 110 to the apparatus 100 as the portable device 110 is being charged. Once the portable device 110 is charged to a predetermined level, the magnetic field generated by the electromagnet 120 can be removed, which can allow a user to easily remove the portable device 110 from the apparatus 100. This process, which will be further described below, can give a tactile indication as to the charging status of the portable device 110. That is, if a user attempts to remove the portable device 110 from the apparatus 100 before the portable device 110 is charged to the predetermined level, the user may find it difficult (if not impossible) to do so. Conversely, if the portable device 110 has been charged to a level above the predetermined level, the user will find it easy to remove the portable device 110 from the apparatus 100 because the generated magnetic field has been eliminated or at least substantially eliminated. It is understood that the invention is in no way limited to this particular example, as other embodiments are within contemplation of the inventive arrangements. Some of these alternative embodiments will be described below. Referring to FIG. 2, a front-sectional view of the portable device 110 coupled to the apparatus 100 is shown. To show the components to be discussed, a portion of the front of the apparatus 100 has been removed, and only a portion of the portable device 110 is pictured. As can be seen, the contacts 122 of the portable device 110 are electrically coupled to the contacts 118 of the apparatus 100, which can permit charging current to flow to the portable device 110. Additionally, the apparatus 100 can electromagnetically engage the portable device 110. Specifically, the electromagnet 120 can be energized and can attract the magnetically susceptible component 124 of the portable device 110. The term electromagnetically engage can mean the process of using a magnetic field to secure the portable device to the apparatus 100 for purposes of providing a user a tactile indication as to the status of the charging of the portable device 110. As the portable device 110 is charged towards the predetermined level, the apparatus 100 can eventually electromagnetically decouple the portable device 110. Once electromagnetically decoupled, a user can remove the portable device 110 from the apparatus 100. The term electromagnetically decouple can mean the process of eliminating a magnetic field, whether substantially instantaneously or through a gradual weakening, to permit a user to remove the portable device 110 from the apparatus 100 when the portable device 110 has been charged to a predetermined level. Referring to FIG. 3, several components of the apparatus 100 and the portable device 110 are shown. A power supply 125 can provide charging current to the apparatus 100. In one arrangement, the apparatus 100 can include an indication circuit 126 having at least one electromagnet 120, a charge control circuit 128 for controlling charging current to the portable device 110 and a processor 130 that can control the operation of both the indication circuit 126 and the charge control circuit 128. The indication circuit 126 can be coupled to the input from the power supply 125 and can include, for example, a switch A1 and a corresponding switch A2, which can be located on opposite sides of the electromagnet 120. It is understood, however, that the invention is not limited to this particular indication circuit 126, as other suitable schemes can be used with the invention. The electromagnet 120 is shown as being positioned some distance away from the portable device 110, which has been done to produce a diagram that is easier to follow. Nevertheless, FIG. 3 is merely meant to illustrate examples of the circuits that can be implemented in the invention and as such, cannot be used to limit the positioning of the electromagnet 120. The processor 130 can control the operation of the indication circuit 126 by, for example, manipulating the switches A1 and A2 (note that the actual connections are only partly illustrated to limit confusion when reviewing FIG. 3). By controlling the switches A1 and A2, the processor 130 can direct current through the electromagnet 120, which can cause the electromagnet 120 to generate an attractive magnetic field with respect to the magnetically susceptible component 124 (see FIGS. 1 and 2 of the portable device 110). The charge control circuit 128 can include, for example, a sense resistor RS, a field effect transistor (FET) 132, a blocking diode 134 and an input 136. As is known in the art, the sense resistor RS, through two inputs, and the input 136 can enable the processor 130 to monitor the charging of the portable device 110. The processor 130 can make adjustments to the amount of charging current flowing to the portable device 110 by controlling the FET 132. The charging current can flow through a B+contact and on to one or more cells 138 of the portable device 110. Although not illustrated, those of ordinary skill in the art will appreciate that the processor 130 can have analog-to-digital (A/D) converters for digitally converting the inputs described above. It is also understood that the invention is not limited to this particular charge control circuit 128, as other suitable schemes can be employed with the invention. The apparatus 100 can also include a sensor 140. The sensor 140 can include a voltage supply Vs, a pull-up resistor R1, a first node 142, a second node 144 and another resistor R2. The sensor 140 has an output that feeds into an input/output (I/O) of the processor 130. The sensor 140 can signal the processor 130 when the portable device 110 is coupled to or removed from the apparatus 100. For example, when the portable device 110 is coupled to the apparatus 100, a circuit can be completed through the first and second nodes 142, 144, which the processor 130 can detect. Similarly, if the portable device 110 is removed from the apparatus 100, the circuit through the first and second nodes 142, 144 is broken, and the processor 130 can identify the change. Again, the invention is not limited to this particular sensor 140, as other suitable schemes can be implemented in the invention. Referring to FIG. 4, another example of several components of the apparatus 100 and the portable device 110 is shown. The arrangement of the apparatus 100 and the portable device 110 is similar to that shown in FIG. 3. That is, the apparatus in FIG. 4 can have an indication circuit 126, a charge control circuit 128, a sensor 140 and all the components that make up these circuits. The primary difference is that the indication circuit 126 of FIG. 4 is in series with the charge control circuit 128. The indication circuit 126 of FIG. 3 can branch off of or be in parallel with the charge control circuit 128. Referring back to FIG. 3, when the power supply 125 is supplying charging current to the apparatus 100, current can also be supplied to the indication circuit 126. For example, the processor 130 can close switches A1 and A2, and the indication circuit 126 can provide an engaging current to the electromagnet 120. This process can cause the electromagnet 120 to generate, for example, an attractive magnetic field with respect to the portable device 110. For purposes of the invention, the term engaging current can mean current that is supplied to the electromagnet 120 that causes the electromagnet 120 to generate a magnetic field. As noted earlier, the apparatus 100 can be used to charge the portable device 110 to a predetermined level, such as a predetermined battery charge capacity. This predetermined level can be a maximum level, such as a maximum battery charge capacity, or something less. When a magnetic field is produced, the generated field can remain at a substantially fixed level as the portable device 110 is charged towards the predetermined level. The reason for the substantially fixed level of the generated field is because the indication circuit 126 is independent of the charge control circuit 128. As is known in the art, as a battery (such as one that can be coupled to the portable device 110) is charged, the amount of charging current that is supplied to the battery may decrease. This decrease in current that may occur in the charge control circuit 128 will not affect the amount of current reaching the indication circuit 126. Referring to FIG. 4, as the portable device 110 is charged towards the predetermined level, the charging current supplied to the portable device 110 may decrease, as described above. In this arrangement, however, if switches A1 and A2 are closed, the strength of the magnetic field generated by the electromagnet 120 may correspondingly decrease, too. As an example, the magnetic field may be an attractive magnetic field in relation to the portable device 110. As the amount of charging current drops in response to the portable device 110 being charged towards the predetermined level, the strength of the attractive magnetic field can decrease, too. A user can sense the drop in attraction between the apparatus 100 and the portable device 110, which can provide an indication that the portable device is nearing its charge capacity. The apparatus 100 can also be designed to produce a repulsive magnetic field, which can be used to assist in the charging of the portable device 110. An example of such a construction is illustrated in FIGS. 5 and 6. Here, the portable device 110 can include one or more extensions 146 that can include a top surface 148. In one arrangement, the contacts 122 for the portable device 110 can be located on the top surface 148 of the extensions 146. As another example, the magnetically susceptible component 124 can be attached near the bottom of the portable device 110. The magnetically susceptible component 124 can be a magnet that has a like pole with respect to the magnetic field that the electromagnet 120 of the apparatus 100 will generate. As shown in FIG. 5, the electromagnet 120 can be positioned on a first surface 116 of the apparatus 100. The contacts 118 that correspond to the contacts 122 of the portable device 100 can be located on a second surface 152 of the apparatus 100. The contacts 118, because they are hidden from view, are represented by dashed outlines. In this arrangement, the first surface 116 can be opposed to the second surface 152. The apparatus 100 can also have a front opening 151 for receiving the portable device 110 and a cavity 153 for receiving the portable device 110 when the apparatus 100 electromagnetically decouples the portable device 110. The electromagnet 120 can be positioned within this cavity 153. Referring to FIG. 6, a front-sectional view of the portable device 110 coupled to the apparatus 100 is shown (only a portion of the portable device 110 is illustrated). The portable device 110 can be coupled to the apparatus 100 by sliding the portable device 110 into the front opening 151 of the apparatus 100. In this example, the electromagnet 120 can generate a magnetic field that repels the magnetically susceptible component 124 of the portable device 110. That is, the magnetically susceptible component 124 can be a magnet that has a like pole as compared to the generated magnetic field. This repulsion can urge the portable device 110 upwards such that the contacts 122 of the portable device 110 are electrically coupled to the contacts 118 of the apparatus 100 to enable charging current to be provided to the portable device 110. In this example, the apparatus 100 has electromagnetically engaged the portable device 110. In one arrangement, the apparatus 100 can have one or more blocking segments 154 (see also FIG. 5). When the portable device 110 is electromagnetically engaged to the apparatus 100, the blocking segments 154 can impede the forward movement of the extensions 146 of the portable device 110. This obstruction can prevent the removal of the portable device 110 from the apparatus 100 when the electromagnet 120 is generating the repulsive magnetic field. When the repulsive magnetic field is removed or at least substantially weakened, the portable device 110 may drop, which will then permit the extensions 146 to clear the blocking segments 154. At this point, the apparatus 100 has electromagnetically decoupled the portable device 110, and the portable device 110 can be moved forward to allow its removal from the apparatus 100. Although not shown here, those of ordinary skill in the art will appreciate that structural support features (in addition to or in lieu of the cavity 153) may be added to the portable device 110 and/or the apparatus 100. These support features can help stabilize the portable device 110 as the apparatus 100 electromagnetically engages and decouples the portable device 110. Moreover, it is understood that the invention is in no way limited to the structure illustrated in FIGS. 5 and 6. That is, both the portable device 110 and the apparatus 100 can be constructed in various ways to implement charging of the portable device 110 using a repulsive magnetic field. To produce the repulsive magnetic field, the components illustrated in FIGS. 3 and 4 can be used. To produce the repulsive force, the magnetically susceptible component 124 of the portable device 110 can be a like pole magnet with respect to the electromagnet 120. In accordance with the discussion relating to FIGS. 3 and 4, the repulsive magnetic field can remain at a substantially fixed level as the portable device 110 is charged towards a predetermined level. Alternatively, the repulsive magnetic field can decrease in strength as the portable device 110 is charged towards a predetermined level. Referring to FIG. 7, another example of a portable device 110 and an apparatus 100 for indication of a charging condition is shown. In this example, the apparatus 100 and the portable device 110 can be somewhat structurally similar to the apparatus 100 and the portable device 110 of FIG. 5. That is, the portable device 110 can have one or more extensions 146 and a magnetically susceptible component 124. Additionally, the apparatus 100 can include a cavity 153 and an electromagnet 120 positioned inside the cavity 153 on the first surface 116. Here, however, the contacts 122 for the portable device 110 can be located at or near the bottom of the portable device 110. Also, the contacts 118 of the apparatus 100 can be positioned on the first surface 116. In this arrangement, the apparatus 100 can generate an attractive magnetic field, and when the portable device 110 is charged to a predetermined level, the apparatus 100 can generate a repulsive magnetic field. To accomplish such a process, the magnetically susceptible component 124 can be a magnet having a predetermined pole. Referring to FIG. 8, the apparatus 100 can electromagnetically engage the portable device 110 in a first position in which the electromagnet 120 is generating an attractive magnetic field with respect to the magnetically susceptible component 124. Only a portion of the portable device 110 is shown here, and part of the apparatus 100 has been removed to show more clearly some of the components. The contacts 118 of the apparatus 100 can be electrically coupled to the contacts 122 of the portable device 110, thereby allowing charging current to flow to the portable device 110. Referring to FIG. 9, the apparatus 100 can electromagnetically engage the portable device 110 in a second position. This process can occur when the portable device 110 has been charged to a predetermined level or capacity. When the portable device 110 is in the second position, a user is given an indication that the portable device 110 is fully charged. To urge the portable device 110 in the second position, the electromagnet 120 can generate a repulsive magnetic field with respect to the magnetically susceptible component 124. In this arrangement, the projections 146 can rest against an inner surface 156 of the apparatus 100 to help keep the portable device 110 in place when the repulsive magnetic field is being generated. In this second position, the contacts 118 and the contacts 122 are no longer electrically coupled, and the flow of charging current to the portable device 110 can stop. In addition, the portable device 110 can be easily removed from the apparatus 100 by moving it forward through an opening 151 of the apparatus 100. While not shown here, those of ordinary skill in the art will appreciate that structure for supporting the portable device 110, in addition to the cavity 153, can be incorporated in the portable device 110 and/or the apparatus 100. The supporting structure can support the portable device 110 in both the first and second positions. Moreover, it is understood that the invention is not limited to the portable device 110 and the apparatus 100 shown in FIGS. 7-9, as other suitable designs are within contemplation of the inventive arrangements. Those of skill in the art will also appreciate that the apparatus 100 could be designed to generate a repulsive magnetic field during the charging phase and an attractive magnetic field once the portable device 110 has been charged to the predetermined level as an alternative to the process explained above. Referring to FIG. 10, a circuit for carrying out the process described in relation to FIGS. 7-9 is shown. This circuit can be like the one presented in FIG. 3. The indication circuit 126 in FIG. 10 can be different in that it can contain two sets of switches, A1, A2, B1 and B2. The switches A1 and A2 can be located on opposite sides of the electromagnet 120. Similarly, the switches B1 and B2 can be positioned on opposite sides of the electromagnet 120. The switches A1, A2, B1 and B2 can be under the control of the processor 130. To generate the attractive magnetic field, the processor can close the switches A1 and A2 (keeping the switches B1 and B2 open), which can provide an engaging current to the electromagnet 120 and as described earlier in relation to FIG. 3. To generate the repulsive magnetic field, the processor 130 can close the switches B1 and B2 (keeping the switches A1 and A2 open). This step can cause current to flow in a direction opposite to the flow of current when the switches A1 and A2 are closed. The processor 130 can open the switches A1 and A2 and close the switches B1 and B2 when the portable device 110 has been charged to a predetermined level. Referring to FIG. 11, another circuit for carrying out the process described in relation to FIGS. 7-9 is shown. This circuit can be like the one presented in FIG. 4. For example, at least part of the indication circuit 126 can be in series with the charge control circuit 128, particularly the electromagnet 120 and the switches A1 and A2. In this arrangement, the attractive magnetic field that the electromagnet 120 generates can decrease as the level of charging current that flows to the portable device 110 decreases. Once the portable device 110 has been charged to the predetermined level and the charging current to it has been removed, the indication circuit 126 may still supply an engaging current to the electromagnet 120 to permit it to generate the repulsive magnetic field. To do so, part of the indication control circuit 126 may branch off of or be in parallel with the charge control circuit 128. For example, the switches B1 and B2 can be used to direct current in an opposite direction to that provided by the switches A1 and A2 with the switch B1 coupled to ground. This part of the indication circuit 126 can be independent of the charge control circuit 128, thereby allowing the strength of the repulsive magnetic field to stay at a substantially fixed level. To carry out the processes described in relation to FIGS. 7-9, it is understood that the invention is in no way limited to the components shown in FIGS. 10 and 11. For example, other suitable indication circuits and charge control circuits can be used to practice the invention. Those of ordinary skill in the art will also appreciate that the invention can be designed such that the portable device 110 is initially repelled to a first position by the electromagnet 120 and then charged while in this first position (similar to the process described in relation to FIGS. 5 and 6). Once the portable device is charged, the electromagnet 120 can then generate an attractive magnetic field, and the portable device 110 can move into a second position in the apparatus 100. By moving into the second position, a user can be given an indication that the portable device 110 has been charged. The attractive magnetic field can be relatively weak to permit a user to easily remove the portable device 110 from the apparatus 100. Referring to FIG. 12, a method 1200 for indication of a charging condition is illustrated. To describe the method 1200, reference may be made to FIGS. 1-6, although it must be noted that the method 1200 can be practiced in other suitable systems. At step 1210, the method 1200 can begin. As shown at step 1220, a charging unit can electromagnetically engage a portable device such that the portable device is magnetically urged towards and secured to at least a portion of the charging unit. At step 1230, a charging current can be supplied to the portable device. In addition, at step 1240, an engaging current can be provided to at least one electromagnet of the charging unit, which can cause the electromagnet to generate either an attractive magnetic field or a repulsive magnetic field with respect to the portable device. For example, referring to FIGS. 1-6, the switches A1 and A2 can be closed, and an engaging current can be supplied to the electromagnet 120 of the apparatus 100. The electromagnet 120 can then generate either an attractive magnetic field or a repulsive magnetic field with respect to the portable device 110. Depending on the type of field generated, the apparatus 100 can magnetically urge the portable device 110 towards a portion of the apparatus 100. The portable device 110 can also be secured to this portion of the apparatus 100. Examples include the arrangements shown in FIGS. 2 and 6. At this point, the apparatus 100, through the charge control circuit 128, can provide charging current to the portable device 110. Referring back to the method 1200 of FIG. 12, at decision block 1250, it can be determined whether the strength of the magnetic field will be maintained at a substantially fixed level or decreased. If it will be a substantially fixed level, at step 1260, the strength of the magnetic field can be maintained at the substantially fixed level as the portable device is charged towards the predetermined level. If it will be decreased, at step 1270, the strength of the magnetic field can be decreased as the portable device is charged towards the predetermined level. For example, if it is desired to keep the strength of the magnetic field (whether attractive or repulsive) at a substantially fixed level as the portable device 110 is being charged to the predetermined level, the configuration of the indication circuit 126 as pictured in FIG. 3 is suitable. Conversely, if it desired to decrease the strength of the magnetic field (whether attractive or repulsive) as the portable device 110 is charged to the predetermined level, the indication circuit 126 as shown in FIG. 4 can be useful. Referring back to FIG. 12, at step 1280, when the portable device is charged to a predetermined level, the portable device can be electromagnetically decoupled from the charging unit to permit a user to remove the portable device from the charging unit. For example, referring to FIGS. 1-6, when the portable device 110 has been charged to a predetermined level, the apparatus 100 can electromagnetically decouple the portable device 110. Specifically referring to FIGS. 3 and 4, when the portable device 110 has been charged to the predetermined level, the switches A1 and A2 can be opened, which will stop the flow of the engaging current to the electromagnet 120. The removal of this current can cause the generated magnetic field to collapse, which can allow the portable device 110 to be removed from the apparatus 100. In one arrangement, the predetermined level can be a maximum battery charge capacity for a battery that will supply power to the portable device 110. The predetermined level, however, may also be a charge capacity that is below the maximum battery charge capacity. Moving back to FIG. 12, at decision block 1285, it can be determined whether the portable device has been removed from the charging unit. If it has, the charging unit can be set to a predetermined charging configuration, as shown at step 1290. If the portable device has not yet been removed, the method 1200 can resume at the decision block 1285. Following step 1290, the method 1200 can end at step 1295. An example of the setting step 1290 will be presented. Referring to FIGS. 3 and 4 and as noted earlier, when the portable device 110 is charged to the predetermined level, the switches A1 and A2 can open, which eliminates the magnetic field. When a user removes the portable device 110, the circuit created between the first and second nodes 142 and 144 of the sensor 140 is broken. This break in the circuit can be signaled to the processor 130. In response, the processor 130 can set the switches A1 and A2 to a predetermined configuration, such as closing both of them. By closing the switches A1 and A2, the apparatus 100 can be made ready to receive the portable device 110 once again. As an option, a time delay can be programmed into the processor 130 to ensure that the switches A1 and A2 are not set too soon. Setting the switches A1 and A2 too soon may interfere with the user removing the portable device 110 from the apparatus 100. It must be noted, however, that the invention is not limited to this particular setting configuration, as other suitable configurations are contemplated by the inventive arrangements. This principle is particularly applicable because the invention is not limited to the indication circuit 126 of FIGS. 3 and 4. Moreover, the invention is not limited to the sensor 140 as depicted in these drawings, as virtually any other means for detecting when the portable device 110 has been removed from the apparatus 100 can be employed. Referring to FIG. 13, another method 1300 for indication of a charging condition is illustrated. The method 1300 is somewhat similar to the method 1200, although reference will be made to FIGS. 7-11 when describing the method 1300. It is understood that the method 1300 can be practiced in other suitable systems, though. At step 1310, the method can begin. At step 1320, a charging unit can electromagnetically engage a portable device in a first position such that the portable device is magnetically urged towards and secured to at least a first portion of the charging unit. For example, the apparatus 100 can electromagnetically engage the portable device 110 in a first position, an example of which is shown in FIG. 8. As noted earlier, in this case, the electromagnet 120 can generate an attractive magnetic field with respect to the magnetically susceptible component 124 of the portable device 110. Referring to FIGS. 10 and 11, the processor 130 can close the switches A1 and A2 and can open the switches B1 and B2. Moving back to the method 1300 of FIG. 13, charging current can then be supplied to the portable device, as shown at step 1330. For example, referring to FIGS. 10 and 11 again, the apparatus 100, through the charge control circuit 128, can provide charging current to the portable device 110. At step 1340 of FIG. 13, when the portable device is charged to a predetermined level, the charging unit can electromagnetically engage the portable device in a second position such that the portable device is magnetically urged towards and secured to a second portion of the charging unit. When the portable device is in the second position, the charging current can be stopped, and a user can be permitted to remove the portable device from the charging unit. The method can end at step 1350. For example, once the portable device 110 is charged to the predetermined level, the apparatus 100 can electromagnetically engage the portable device in a second position, an example of which is shown in FIG. 9. In this case, the electromagnet 120 can generate a repulsive magnetic field with respect to the magnetically susceptible component 124 of the portable device 110. Referring to FIGS. 10 and 11, the processor 130 can open the switches A1 and A2 and can close the switches B1 and B2. When the portable device 110 is in the second position, the user can them remove the portable device 110 from the apparatus 100. Similar to the method 1200, when the portable device 110 is removed, the apparatus 100 can detect the removal and can be set to a predetermined charging configuration. For example, once the processor 130 detects the removal (through the sensor 140), the processor 130 can open the switches B1 and B2 and can close the switches A1 and A2. The apparatus 100 can once again receive the portable device 110 for charging. It must be noted, however, that the method 1300 is not limited to the process described above. For example, the portable device 110 can be repelled in the first position with a repulsive magnetic field during the charging phase. Further, the portable device 110 can be attracted to the second position with an attractive magnetic field once the portable device 110 is charged to the predetermined level. In addition, while the preferred embodiments of the invention have been illustrated and described, it will be clear that the invention is not so limited. Numerous modifications, changes, variations, substitutions and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention This invention relates in general to energy management and more particularly to methods for charging batteries. 2. Description of the Related Art Portable electronic devices, such as cellular telephones and personal digital assistants, have become very popular in today's marketplace. Virtually all of these devices receive their power from a portable, rechargeable battery. For some models, the portable electronic device is coupled to a charging unit, such as a desktop charger, to allow the battery of the portable electronic device to be recharged. Presently, when a battery is fully charged, there are several visual indicators that may be employed to provide notice to a user that the battery is ready for use. For example, many portable electronic devices, such as cellular telephones, display a message that indicates that the charging process is complete. Alternatively, some of the charging units are equipped with a light emitting diode (LED) to signal when the battery is charged to capacity. Such indicators may be useful to many users; however, some users may suffer from poor or impaired vision, which may prevent them from determining when the portable electronic device is ready for use. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention concerns an apparatus for indication of a charging condition. The apparatus includes an indication circuit having at least one electromagnet and a charge control circuit for controlling charging current to a portable device. The indication circuit causes the apparatus to electromagnetically engage the portable device, and the charge control circuit provides charging current to the portable device during the engagement. In addition, the indication circuit causes the apparatus to electromagnetically decouple the portable device when the portable device is charged to a predetermined level to permit a user to remove the portable device from the apparatus. The apparatus can also include at least one contact. The apparatus contact can electrically couple to a contact of the portable device when the apparatus electromagnetically engages the portable device. In one arrangement, the indication circuit can provide an engaging current to the electromagnet. The engaging current can cause the electromagnet to generate at least one of an attractive magnetic field and a repulsive magnetic field. As an example, when the electromagnet generates an attractive magnetic field, the electromagnet can attract at least one of a non-magnetized, metallic component of the portable device and an opposite pole magnet of the portable device. Alternatively, when the electromagnet generates a repulsive magnetic field, the electromagnet can repel a like pole magnet of the portable device. In another arrangement, the electromagnet and the contacts can be positioned on a first surface of the apparatus. Also, the electromagnet can be positioned on a first surface of the apparatus, and the contacts can be positioned on a second surface of the apparatus in which the second surface can oppose the first surface. In one embodiment of the invention, the electromagnet can generate a magnetic field when the apparatus electromagnetically engages the portable device, and the magnetic field can decrease in strength as the portable device is charged towards the predetermined level. As an example, the indication circuit and the charge control circuit can be in series. In another embodiment, the electromagnet can generate a magnetic field when the apparatus electromagnetically engages the portable device, and the magnetic field can remain at a substantially fixed level as the portable device is charged towards the predetermined level. In this arrangement, the indication circuit and the charge control circuit can be in parallel. The apparatus can also include a sensor for determining whether the portable device has been removed from the apparatus. The present invention also concerns another apparatus for indication of a charging condition. The apparatus can include an indication circuit having at least one electromagnet and a charge control circuit for controlling charging current to a portable device. The indication circuit causes the apparatus to electromagnetically engage the portable device in a first position, and the charge control circuit can provide charging current to the portable device during the first position engagement. The indication circuit causes the apparatus to electromagnetically engage the portable device in a second position when the portable device is charged to a predetermined level such that the charge control circuit stops providing charging current to the portable device and a user is permitted to remove the portable device from the apparatus. The present invention also concerns a portable device. The portable device includes at least one contact for electrically coupling to at least one corresponding contact on a charging unit and a magnetically susceptible component. The charging unit electromagnetically engages the magnetically susceptible component and provides a charging current to the portable device through the contacts of the portable device and the corresponding contacts of the charging unit during the engagement. In addition, the charging unit electromagnetically decouples the portable device when the portable device is charged to a predetermined level to permit a user to remove the portable device from the charging unit. In one arrangement, the magnetically susceptible component can be a non-magnetized, metallic component or a magnet. As an example, the magnet of the portable device can be a like pole magnet with respect to an electromagnet in the charging unit such that the electromagnet can generate a repulsive magnetic field when the charging unit electromagnetically engages the portable device. The present invention also concerns a method for indication of a charging condition. The method can include the steps of electromagnetically engaging a portable device to a charging unit such that the portable device is magnetically urged towards and secured to at least a portion of the charging unit, supplying charging current to the portable device and when the portable device is charged to a predetermined level, electromagnetically decoupling the portable device from the charging unit to permit a user to remove the portable device from the charging unit. The method can also include the steps of providing an engaging current to at least one electromagnet of the charging unit. This step can cause the electromagnet to generate at least one of an attractive magnetic field and a repulsive magnetic field. Further, the charging unit can have at least one electromagnet, and the method can also include the steps of generating a magnetic field during the electromagnetically engaging step and decreasing the strength of the magnetic field as the portable device is charged towards the predetermined level. As an alternative, the method can further include the step of keeping the strength of the magnetic field at a substantially constant level as the portable device is charged towards the predetermined level. In one arrangement, the method can include the steps of determining whether the portable device has been removed from the charging unit and in response to the portable device being removed from the charging unit, setting the charging unit to a predetermined charging configuration. In another arrangement, the electromagnetically engaging step can include magnetically urging and securing the portable device to the charging unit with an attractive magnetic field, and the electromagnetically decoupling step can include removing the attractive magnetic field. Alternatively, the electromagnetically engaging step can include magnetically urging and securing the portable device to the charging unit with a repulsive magnetic field, and the electromagnetically decoupling step can include removing the repulsive magnetic field. The present invention also concerns another method for indication of a charging condition. The method includes the steps of electromagnetically engaging a portable device to a charging unit in a first position such that the portable device is magnetically urged towards and secured to at least a first portion of the charging unit, supplying charging current to the portable device and when the portable device is charged to a predetermined level, electromagnetically engaging the portable device to the charging unit in a second position such that the portable device is magnetically urged towards and secured to a second portion of the charging unit. When the portable device is in the second position, the charging current is stopped, and a user is permitted to remove the portable device from the charging unit. | 20040408 | 20060328 | 20051013 | 99669.0 | 0 | TIBBITS, PIA FLORENCE | METHOD AND APPARATUS FOR INDICATION OF A CHARGING CONDITION | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,821,027 | ACCEPTED | Dorsal pad assembly for use with a safety harness | A preferred embodiment safety harness includes two straps operatively connected to a D-ring, which is operatively connected to a biasing mechanism urging the D-ring to an upright position. The safety harness may also include an impact indicator for providing indication when the D-ring has been subjected to a force and a wear pad for reducing wear on the straps of the safety harness. | 1. A safety harness, comprising: a) a first strap and a second strap; b) a D-ring operatively connected to the straps having a first position and a second position, the first position being an upright receiving position, the second position being a connected operating position; and c) a biasing mechanism operatively connected to the D-ring, wherein the biasing mechanism urges the D-ring to the first position. 2. The safety harness of claim 1, wherein the biasing mechanism is a spring member. 3. The safety harness of claim 1, wherein the biasing mechanism is an elastic member. 4. The safety harness of claim 1, further comprising an impact indicator operatively connected to the D-ring, wherein the impact indicator provides indication when the D-ring has been subjected to a force. 5. The safety harness of claim 4, wherein the force is at least 500 pounds. 6. The safety harness of claim 4, wherein the impact indicator is an indication mark on the D-ring that is exposed when the D-ring has been subjected to a force. 7. The safety harness of claim 4, wherein the impact indicator is an ink filled pellet that stains the straps when the D-ring has been subjected to a force. 8. The safety harness of claim 4, further comprising a dorsal pad assembly interconnecting the straps and the D-ring. 9. The safety harness of claim 1, further comprising a dorsal pad assembly interconnecting the straps and the D-ring. 10. The safety harness of claim 9, wherein the dorsal pad assembly includes the biasing mechanism. 11. The safety harness of claim 10, wherein the dorsal pad assembly includes the impact indicator. 12. The safety harness of claim 11, wherein the impact indicator is a change in appearance of the dorsal pad assembly thereby providing visual indication that the D-ring has been subjected to a force. 13. The safety harness of claim 1, further comprising a wear pad operatively connected to the D-ring, the wear pad reducing wear on the straps. 14. A safety harness, comprising: a) a first strap and a second strap; b) a D-ring operatively connected to the straps; and c) an impact indicator operatively connected to the D-ring, the impact indicator providing indication when the D-ring has been subjected to a force. 15. The safety harness of claim 14, wherein the impact indicator is an indication mark on the D-ring that is exposed when the D-ring has been subjected to a force. 16. The safety harness of claim 14, wherein the impact indicator is an ink filled pellet that stains the straps when the D-ring has been subjected to a force. 17. The safety harness of claim 14, wherein the impact indicator is a clip member. 18. The safety harness of claim 14, further comprising a dorsal pad assembly interconnecting the straps and the D-ring, the dorsal pad assembly including the impact indicator. 19. The safety harness of claim 18, wherein the impact indicator is a change in appearance of the dorsal pad assembly thereby providing visual indication that the D-ring has been subjected to a force. 20. The safety harness of claim 18, wherein the impact indicator is a clip member. 21. The safety harness of claim 14, further comprising a biasing mechanism operatively connected to the D-ring, the D-ring having a first position and a second position, the first position being an upright receiving position, the second position being a connected operating position, the biasing mechanism urging the D-ring to the first position. 22. The safety harness of claim 21, wherein the biasing mechanism is a spring member. 23. The safety harness of claim 21, wherein the biasing mechanism is an elastic member. 24. A safety harness having a first strap and a second strap, comprising: a) a D-ring operatively connected to the straps having a first position and a second position, the first position being an upright receiving position, the second position being a connected operating position; and b) means for urging the D-ring to the first position. 25. The safety harness of claim 24, further comprising a dorsal pad assembly, the dorsal pad assembly including the means for urging the D-ring to the first position. 26. The safety harness of claim 25, further comprising means for providing indication that the D-ring has been subjected to a force. 27. The safety harness of claim 26, wherein the dorsal pad assembly includes the means for providing indication that the D-ring has been subjected to a force. 28. A dorsal pad assembly for use with a safety harness having a first strap and a second strap, comprising: a) a D-ring operatively connected to the straps having a first position and a second position, the first position being an upright receiving position, the second position being a connected operating position; b) a biasing mechanism operatively connected to the D-ring, the biasing mechanism urging the D-ring to the first position; and c) an impact indicator operatively connected to the D-ring, the impact indicator providing indication when the D-ring has been subjected to a force. 29. A dorsal pad assembly for use with a safety harness including straps, comprising: a) a D-ring having a bar portion, a first position, and a second position, the first position being an upright receiving position, the second position being a connected operating position; b) a D-ring clip having a cavity, the bar portion of the D-ring being positioned within the cavity and being engaged by the D-ring clip; c) a dorsal pad having slots and a D-ring connector portion, the straps of the harness being routed through the slots, the D-ring connector portion having a second cavity, the D-ring clip being positioned within the second cavity and being engaged by the dorsal pad; and d) a biasing mechanism interconnecting the D-ring clip and the dorsal pad, the biasing mechanism applying a force on the D-ring clip thereby urging the D-ring to the first position, wherein when the D-ring is placed in the second position and the biasing mechanism urges the D-ring to the first position. 30. The dorsal pad assembly of claim 29, further comprising a catch operatively connected to the D-ring clip, the catch extending into the cavity of the D-ring clip and releasably holding the bar portion of the D-ring within the cavity. 31. The dorsal pad assembly of claim 30, wherein the catch releases the bar portion when a force is exerted upon the D-ring thereby providing visual indication that the D-ring has been subjected to a force. 32. The dorsal pad assembly of claim 31, the force being at least 500 pounds. 33. The dorsal pad assembly of claim 29, further comprising lips operatively connected to the dorsal pad proximate the second cavity, the straps of the harness being routed over the lips, the lips protecting the straps from the D-ring clip as the D-ring clip pivots within the second cavity thereby reducing wear on the straps of the harness. 34. A method of securing a safety harness donned by a user to a connector of a safety device, comprising: a) constantly urging a D-ring operatively connected to straps of the safety harness to an upright position relative to the user, the D-ring having a first position and a second position, the first position being an upright receiving position, the second position being a connected operating position; and b) securing the connector of the safety device to the D-ring in the upright receiving position. 35. The method of claim 34, further comprising performing tasks proximate the safety device, the D-ring being in the second position and being constantly urged to the first position. 36. The method of claim 35, further comprising disconnecting the connector from the D-ring, the D-ring returning to the first position. 37. A dorsal pad assembly for use with a safety harness having a first strap and a second strap, comprising: a) a D-ring operatively connected to the straps having a first position and a second position, the first position being an upright receiving position, the second position being an impact indicator position; and b) a mechanism operatively connected to the dorsal pad assembly, the mechanism substantially holding the D-ring in the first position and allowing the D-ring to be in the second position when the D-ring has been subjected to a force. 38. The dorsal pad assembly of claim 37, wherein the mechanism is a biasing mechanism. 39. The dorsal pad assembly of claim 37, wherein the mechanism is a clip member. 40. The dorsal pad assembly of claim 37, wherein the second position provides indication that the D-ring has been subjected to a force. 41. A dorsal pad assembly for use with a safety harness having a first strap and a second strap, comprising: a) a D-ring operatively connected to the straps having a first position and a second position, the first position being an upright receiving position, the second position being an impact indicator position; and b) means for substantially holding the D-ring in the first position and allowing the D-ring to be in the second position when the D-ring has been subjected to a force. 42. The dorsal pad assembly of claim 41, wherein the mechanism is a biasing mechanism. 43. The dorsal pad assembly of claim 41, wherein the mechanism is a clip member. 44. The dorsal pad assembly of claim 41, wherein the second position provides indication that the D-ring has been subjected to a force. | This application claims the benefit of U.S. Provisional Application No. 60/500,597, filed Sep. 5, 2003. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety harness and components thereof. 2. Description of the Prior Art Various occupations place people in precarious positions at relatively dangerous heights thereby creating a need for fall-arresting safety apparatus. Among other things, such apparatus usually include a safety line interconnected between a support structure and a person working in proximity to the support structure. The safety line is typically secured to a full-body safety harness worn by the worker. Obviously, such a harness must be designed to remain secure about the worker in the event of a fall. In addition, the harness should arrest a person's fall in as safe a manner as possible, placing a minimal amount of strain on the person's body. Yet another design consideration is to minimize the extent to which people may consider the harness uncomfortable and/or cumbersome. In addition, there is a need for a more user-friendly safety harness. For example, it is often difficult and/or cumbersome to connect the safety harness to a safety line. Further, once a safety harness has been subjected to forces from a fall, the safety harness must be discarded. It is often difficult to determine whether a safety harness has been subjected to forces from a fall or an impact. SUMMARY OF THE INVENTION In a preferred embodiment safety harness, the safety harness includes a first strap, a second strap, a D-ring, and a biasing mechanism. The D-ring is operatively connected to the straps and has a first position and a second position. The first position is an upright receiving position, and the second position is a connected operating position. The biasing mechanism is operatively connected to the D-ring, and the biasing mechanism urges the D-ring to the first position. In another preferred embodiment safety harness, the safety harness includes a first strap, a second strap, a D-ring, and an impact indicator. The D-ring is operatively connected to the straps, and the impact indicator is operatively connected to the D-ring. The impact indicator provides indication when the D-ring has been subjected to a force. In a preferred embodiment safety harness having a first strap and a second strap, a D-ring is operatively connected to the straps. The D-ring has a first position and a second position. The first position is an upright receiving position, and the second position is a connected operating position. The safety harness also includes means for urging the D-ring to the first position. In a preferred embodiment dorsal pad assembly for use with a safety harness having a first strap and a second strap, a D-ring is operatively connected to the straps. The D-ring has a first position and a second position. The first position is an upright receiving position, and the second position is a connected operating position. A biasing mechanism is operatively connected to the D-ring, and the biasing mechanism urging the D-ring to the first position. An impact indicator is operatively connected to the D-ring, and the impact indicator provides indication when the D-ring has been subjected to a force. In a preferred embodiment dorsal pad assembly for use with a safety harness including straps, a D-ring has a bar portion, a first position, and a second position. The first position is an upright receiving position, and the second position is a connected operating position. A D-ring clip has a cavity, and the bar portion of the D-ring is positioned within the cavity and is engaged by the D-ring clip. A dorsal pad has slots and a D-ring connector portion. The straps of the harness are routed through the slots, and the D-ring connector portion has a second cavity. The D-ring clip is positioned within the second cavity and is engaged by the dorsal pad. A biasing mechanism interconnects the D-ring clip and the dorsal pad, and the biasing mechanism applies a force on the D-ring clip thereby urging the D-ring to the first position. When the D-ring is placed in the second position, the biasing mechanism urges the D-ring to the first position. In a preferred embodiment method of securing a safety harness donned by a user to a connector of a safety device, a D-ring operatively connected to straps of the safety harness is constantly urged to an upright position relative to the user. The D-ring has a first position and a second position. The first position is an upright receiving position, and the second position is a connected operating position. The connector of the safety device is secured to the D-ring in the upright receiving position. In another preferred embodiment dorsal pad assembly for use with a safety harness having a first strap and a second strap, a D-ring is operatively connected to the straps and has a first position and a second position. The first position is an upright receiving position, and the second position is an impact indicator position. A mechanism is operatively connected to the dorsal pad assembly, and the mechanism substantially holds the D-ring in the first position and allows the D-ring to be in the second position when the D-ring has been subjected to a force. In another preferred embodiment dorsal pad assembly for use with a safety harness having a first strap and a second strap, a D-ring is operatively connected to the straps and has a first position and a second position. The first position is an upright receiving position, and the second position is an impact indicator position. The dorsal pad assembly also includes means for substantially holding the D-ring in the first position and allowing the D-ring to be in the second position when the D-ring has been subjected to a force. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a D-ring clip and impact indicator constructed according to the principles of the present invention; FIG. 2 is a bottom view of the D-ring clip and impact indicator shown in FIG. 1; FIG. 3 is a top view of the D-ring clip and impact indicator shown in FIG. 1; FIG. 4 is a cross-sectional side view of the D-ring clip and impact indicator shown in FIG. 1 along the lines 4-4 shown in FIG. 3; FIG. 5 is a side view of the D-ring clip and impact indicator shown in FIG. 1; FIG. 6 is a cross-sectional view of the D-ring clip and impact indicator shown in FIG. 1 along the lines 6-6 shown in FIG. 5; FIG. 7A is a front view of a D-ring; FIG. 7B is a front view of the D-ring shown in FIG. 7A engaging straps of a safety harness; FIG. 8 is a perspective view of a combination dorsal pad, D-ring connector, and impact indicator constructed according to the principles of the present invention; FIG. 9A is a front view of a spring for use with the combination dorsal pad, D-ring connector, and impact indicator; FIG. 9B is a side view of the spring shown in FIG. 9A; FIG. 10 is a top view of a D-ring connector constructed according to the principles of the present invention; FIG. 11 is a cross-sectional view of the D-ring connector along the lines 11-11 shown in FIG. 10; FIG. 12 is a cross-sectional view of the D-ring connector along the lines 12-12 shown in FIG. 10; FIG. 13 is a cross-sectional view of the D-ring connector along the lines 13-13 shown in FIG. 10; FIG. 14 is a front side view of the D-ring connector shown in FIG. 10; FIG. 15 is a left side view of the D-ring connector shown in FIG. 10; FIG. 16 is a right side view of the D-ring connector shown in FIG. 10; FIG. 17 is a bottom view of the D-ring connector shown in FIG. 10; FIG. 17A is a bottom view of the D-ring connector shown in FIG. 10 with the D-ring clip and impact indicator shown in FIG. 1 and the spring shown in FIG. 9A; FIG. 18 is a cross-sectional view of the D-ring connector shown in FIG. 10 along the lines 18-18 shown in FIG. 17; FIG. 19 is a cross-sectional view of the D-ring connector shown in FIG. 10 along the lines 19-19 shown in FIG. 17; FIG. 20 is a front view of a dorsal D-ring pad assembly constructed according to the principles of the present invention; FIG. 21 is a side cross-sectional view of the dorsal D-ring pad assembly shown in FIG. 20; FIG. 22 is a front view of another dorsal D-ring pad assembly constructed according to the principles of the present invention; FIG. 23 is a side cross-sectional view of the dorsal D-ring pad assembly shown in FIG. 22; FIG. 24 is a front view of a wear pad frame and impact indicator operatively connected to a D-ring for use with the dorsal D-ring assembly shown in FIG. 22; FIG. 25 is a front view of another wear pad frame and impact indicator operatively connected to a D-ring for use with the dorsal D-ring assembly shown in FIG. 22; FIG. 26 is a front view of another dorsal D-ring assembly constructed according to the principles of the present invention; FIG. 27 is a front view of a D-ring and a spring operatively connected to the D-ring for use with the dorsal D-ring assembly shown in FIG. 26; FIG. 28 is a front view of a dorsal pad for use with the dorsal D-ring assembly shown in FIG. 26; FIG. 29 is a side view of a wear pad for use with the dorsal D-ring assembly shown in FIG. 26; FIG. 30 is a front view of a dorsal D-ring wear pad assembly constructed according to the principles of the present invention; FIG. 31 is a back view of the dorsal D-ring wear pad assembly shown in FIG. 30; FIG. 32 is a bottom perspective view of the dorsal D-ring wear pad assembly shown in FIG. 30; FIG. 33 is a top perspective view of the dorsal D-ring wear pad assembly shown in FIG. 30; FIG. 34 is a top perspective view of a D-ring engaging portion for use with the dorsal D-ring wear pad assembly shown in FIG. 30; FIG. 35 is a bottom perspective view of a D-ring engaging portion for use with the dorsal D-ring wear pad assembly shown in FIG. 30; FIG. 36 is a perspective view of a wear pad assembly for use with the dorsal D-ring wear pad assembly shown in FIG. 30; FIG. 37 is a front view of the dorsal D-ring wear pad shown in FIG. 30 engaging straps of a safety harness; FIG. 38 is a front view of a D-ring engaging straps of a safety harness for use with the dorsal D-ring wear pad shown in FIG. 30; FIG. 39 is a front view of another dorsal D-ring pad assembly constructed according to the principles of the present invention; FIG. 40 is a side view of the dorsal D-ring pad assembly shown in FIG. 39; FIG. 41 is a front view of a D-ring clip and fall indicator constructed according to the principles of the present invention; FIG. 42 is a bottom view of the D-ring clip and fall indicator shown in FIG. 41; and FIG. 43 is a bottom view of the D-ring clip and fall indicator shown in FIG. 41 after the D-ring clip and fall indicator has been subjected to an impact. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Preferred embodiment safety harnesses and components thereof constructed according to the principles of the present invention are shown in the drawings, wherein like numerals represent like components throughout the drawings. Access to a safety harness and an indication whether a safety harness has been subjected to the force of an impact are among the important features of a safety harness. A dorsal D-ring positioned upright relative to the user and/or the dorsal pad upon which it is operatively connected assists in quickly and easily connecting to a lifeline, a lanyard, a D-ring extension, a shock absorber, a winch, a rope grab, a descent device, or other safety device well known in the art. A carabiner, a snap hook, or other connector well known in the art is typically used to connect the safety device to the D-ring of the safety harness. A biasing mechanism operatively connected to the D-ring to urge the D-ring in an upright position could be used to assist in quickly and easily connecting to a lifeline. The biasing mechanism urges the D-ring into a first position, which is a receiving upright position. The biasing mechanism preferably places a constant force upon the D-ring that may be overcome during use of the D-ring. During use of the D-ring, the D-ring moves in a second position, which is a connected position that varies with the movement of the user and/or the lifeline connected to the D-ring. The second position may include the first position during use of the D-ring. When the D-ring is not being urged in the second position by a lifeline or another device, the D-ring is urged in the first position by the biasing mechanism. Because the lifeline is attached to the D-ring, an indicator operatively connected to the D-ring would be helpful in determining whether the safety harness has been subjected to an impact, in which case the safety harness should be discarded. Alternatively, a mechanism for holding the D-ring in a first position and allowing the D-ring to be in a second position when the D-ring has been subjected to a force could be used. In this instance, the first position is an upright receiving position, and the second position is an impact indicator position. The mechanism could be a biasing mechanism or a clip mechanism, and the D-ring is substantially held in the first position by the mechanism. When an impact has occurred, the mechanism will allow the D-ring to be in the second position from the force of the impact upon the D-ring thereby providing visual indication that the D-ring has been subjected to a force. A preferred embodiment D-ring clip and impact indicator 300 is shown in FIGS. 1-6, and a typical D-ring 310 for use with the D-ring clip and impact indicator 300 is shown in FIG. 7A. A preferred embodiment combination dorsal pad, D-ring connector, and impact indicator 320, hereinafter assembly 320, is shown in FIGS. 8-19, and is configured and arranged for use with the D-ring clip and impact indicator 300. The D-ring 310 includes a ring portion 311 and a bar portion 312, which are interconnected with connecting portions 313 on both sides forming an opening 315 therebetween. The ring portion 311 includes an opening 314 to which a connector may be attached. Between the openings 314 and 315 is an intermediate portion 318. Straps 316a and 316b are threaded through the opening 315 of the D-ring 310 and preferably overlap and criss-cross in divergent fashion, as shown in FIG. 7B, to form the shoulder straps and back straps of the harness. A third strap 317 may be optionally attached at one end to the back of strap 316a, threaded through the opening 315 of the D-ring 310, and then attached at the other end to the back of the strap 316b to fix the D-ring, if desired. The third strap 317 is not used with all styles of safety harnesses and is therefore optional. Stitching 319 may be used to attach the third strap 317 to the straps 316a and 316b. The D-ring 310 is kept in place between the loop of the third strap 317 and the stitching 319. The D-ring clip and impact indicator 300, hereinafter referred to as clip 300, is preferably made of nylon type 6-6 and includes a generally cylindrical housing 301 with a first end 301a, a second end 301b, and a cavity 302 within the housing 301. Operatively connected to the first end 301a is a first rounded end 304 with a head 304a. The head 304a is operatively connected to the end 304 opposite the first end 301a and has a larger diameter than the diameter of the end 304. Operatively connected to the second end 301b is a second rounded end 305 with a lateral slot 305a. The lateral slot 305a is opposite the second end 301b and extends inward toward the second end 301b. The housing 301 also includes a top opening 306 and a bottom opening 307, which provide access to the cavity 302. The top opening 306 is configured and arranged to accept the bar portion 312 of the D-ring 310. The bottom opening 307 is smaller than the top opening 306 and a bottom surface 308 provides a surface upon which the bar portion 312 may rest. Therefore, the bar portion 312 cannot pass through the bottom opening 307. A friction fitting assembly 303 proximate a center portion of the top opening 306 of the housing 301 includes a first catch 303a and a second catch 303b. The catches 303a and 303b are generally triangular protrusions extending partially into the cavity 302. A cross-sectional view of the catches 303a and 303b is shown in FIG. 6. As shown in FIG. 6, the portions of the catches 303a and 303b proximate the top of the housing 301 are angled from the top opening 306 into the cavity 302, and the portions of the catches 303a and 303b proximate the cavity are more horizontal. The angled portion allows the bar portion 312 to slide through the friction fitting assembly 303 into the cavity, and the more horizontal portions provide resistance in removing the bar portion 312 from the cavity 302. In other words, when the bar portion 312 is inserted into the top opening 306, the bar portion 312 forces the catches 303a and 303b apart to be inserted fully into the cavity 302. The bar portion 312 snaps into place as the bar portion 312 deflects the catches 303a and 303b away and then the catches 303a and 303b are deflected back to hold the bar portion 312 in place within the cavity 302 with the catches 303a and 303b. With reference to FIGS. 8-19, the assembly 320 is preferably made of urethane. The assembly 320 includes a dorsal pad 321 and a D-ring connector portion 324 operatively connected thereto. The dorsal pad 321 is generally preferably hexagonal and relatively flat in shape and includes four slots 322 and two slots 323, which are configured and arranged to route straps of a safety harness as is well known in the art. A slot 322 extends parallel to each of two adjacent sides at each end of the dorsal pad 321. In other words, there are two slots 322 at each end of the dorsal pad 321, a slot 322 extending parallel to each of the two adjacent sides forming the end. A slot 323 extends perpendicular to the two remaining sides of the dorsal pad 321 approximately ⅓ the length of the dorsal pad 321 from each end. The dorsal pad 321 also includes triangular indentations 328 between the slots 322 and 323 that are optional but add flexibility to the dorsal pad 321. The bottom 333 of the dorsal pad 321 should face the back of the user. The D-ring connector portion 324 extends between the two remaining sides of the dorsal pad 321 proximate the middle of the dorsal pad 321 between and parallel to the slots 323. The D-ring connector portion 324 is generally cylindrical and configured and arranged to house the D-ring clip and impact indicator 300. The D-ring connector portion 324 includes a top opening 337, a bottom opening 338, a first connecting end 325, a second connecting end 326, and a cavity 329. The top opening 337 is generally rectangular and includes a first lip 335a and a second lip 335b, which extend into the cavity 329. The bottom opening 338 is configured and arranged to receive the D-ring clip and impact indicator 300. As shown in FIGS. 17 and 17A, the first connecting end 325 is configured and arranged to accommodate the first rounded end 304 and the head 304a and the second connecting end 326 is configured and arranged to accommodate the second rounded end 305 and a spring 330. As shown in FIGS. 9A and 9B, the spring 330 includes a D-ring connector engaging portion 331 and a biasing portion 332. Preferably, the spring 330 is a torsion spring made of stainless steel spring wire. The biasing portion 332 should preferably extend upward from the center of the spring 330, and the D-ring connector engaging portion 331 should preferably extend downward beyond the center of the spring 330. The top opening 337 and the bottom opening 338 of the dorsal pad 321 provide access to the cavity 329, which is configured and arranged to accommodate the D-ring clip and impact indicator 300. The cavity 329 includes a first cavity 329a, a second cavity 329b, a third cavity 329c, and a fourth cavity 329d. The first cavity 329a is configured and arranged to accommodate the second rounded end 305, the second cavity 329b is configured and arranged to accommodate the spring 330 about the second rounded end 305, the third cavity 329c is configured and arranged to accommodate the first rounded end 304, and the fourth cavity 329d is configured and arranged to accommodate the head 304a. Slots 329e extend outward proximate the side of second cavity 329b opposite first cavity 329a and are configured and arranged to accommodate the biasing portion 332 of the spring 330, although the biasing portion 332 is preferably placed within only one of the slots 329e. In operation, the D-ring 310 is snapped into place within cavity 302 of the D-ring clip and impact indicator 300. The D-ring connector engaging portion 331 of the spring 330 is inserted within the slot 305a of the second rounded end 305 so that the biasing portion 332 extends in an upwardly direction relative to the D-ring 310. When the D-ring clip and impact indicator 300 and D-ring 310 are inserted through the bottom opening 307, with the D-ring 310 being inserted first, and placed within the cavity 302, the biasing portion 332 extends in an upwardly direction within the slot 329e of the spring engaging end 326. The D-ring clip and impact indicator 300 interconnects the spring 330 and the D-ring 310, and the spring 330 interconnects the D-ring clip and impact indicator 300 and the dorsal pad 321. Held in place within slots 305a and 329e, the spring 330 places a constant force upon the D-ring clip and impact indicator 300 and the dorsal pad 321. The dorsal pad 321 is generally stationary and the D-ring clip and impact indicator 300 is pivotable or rotatable within the cavity 329 of the dorsal pad 321. The spring 330 urges the D-ring clip and impact indicator 300 in an upward (upright) direction relative to the dorsal pad 321 and the user. Because the D-ring 310 is operatively connected to the D-ring clip and impact indicator 300, the D-ring 310 is urged into an upright position with the D-ring clip and impact indicator 300. An upright position is the ring portion 311 of the D-ring 310 extending in an upward direction relative to the dorsal pad 321 and the user. If the D-ring 310 and the D-ring clip and impact indicator 300 are urged downward and rotate in a downward direction, the spring 330 will become coiled tighter. When the spring 330 becomes coiled tighter, the spring 330 wants to become less coiled thereby urging the D-ring 310 back into an upright position. How these components are connected is shown in FIGS. 8 and 17A. When the D-ring clip and impact indicator 300 is inserted through the bottom opening 338 into the cavity 329, the lips 335a and 335b prevent the D-ring clip and impact indicator 300 from coming through the top opening 337. In addition, when harness straps are connected to the dorsal pad 321, the lips 335a and 335b act as a wear pad to prevent the D-ring 310 from rubbing against the straps. When the harness has been subjected to an impact, the D-ring 310 snaps out of the D-ring clip and impact indicator 300 by deflecting catches 303a and 303b, and this change in appearance provides a visual indication to the user that the safety harness should be discarded. In addition, the bar portion 312 of the D-ring 310 could include a colored portion that would become exposed when the D-ring 310 snaps out of the D-ring clip and impact indicator 300 thereby providing additional visual indication that the safety harness should be discarded. In other words, an impact indication mark, such as a colored portion on the bar portion 312 of the D-ring 310, similar to that shown in FIG. 25, may also be used to indicate an impact has occurred. FIGS. 20 and 21 show a preferred embodiment dorsal D-ring pad assembly 400 including a dorsal pad 401, a D-ring 402, and a wear pad 407. The dorsal pad 401 is similarly configured and arranged as the dorsal pad 321. The dorsal pad 401 is generally preferably hexagonal and relatively flat in shape and includes slots 411a, 411b, 412, 413, 414a, and 414b, which are configured and arranged to route straps 408 and 409 of a safety harness as is well known in the art. Slots 411a and 411b are located proximate the top, slots 412 and 413 are located proximate the middle, and slots 414a and 414b are located proximate the bottom of the dorsal pad. The D-ring 402 includes a ring portion 403, a bar portion 404, and slots 405 and 406. The harness straps are inserted through slot 405, and an elastic strap 410 is inserted through the slots 405 and 406. Slot 406 is an additional slot than is not typically included in a D-ring but is used so the elastic strap 410 does not interfere with ring portion 403. The wear pad 407 protects the webbing of the harness straps 408 and 409 along the bar and the side edges of the D-ring 402 proximate the bar portion 404. The wear pad 407 includes a bar protector 407a and a side protector 407b. The wear pad 407 could also include bridges 407c interconnecting the sides of the side protector 407b. The bar protector 407a is positioned over the D-ring 402 bar portion 404 and operatively connected to a connecting portion 416 on the dorsal pad 401. The bar protector 407a protects the straps 408 and 409 from rubbing against the bar portion 404 when the D-ring 402 moves during connection with a lifeline. The connecting portion 416 is preferably located proximate the middle of the D-ring pad assembly 400. For example, the bar protector 407a could snap into an aperture in the connecting portion 416. The bar protector 407a could also be connected to the connecting portion 416 with rivets, ultrasonic welding, glue, or other connecting devices well known in the art. The side protector 407b extends outward proximate the ends of the bar protector 407a and acts as a shield to protect the sides of the straps 408 and 409 from rubbing against the side edges of the D-ring 402. The wear pad 407 does not move with the D-ring 402 and therefore reduces the wear on the straps 408 and 409 as the D-ring 402 rotates. The wear pad 407 could be snapped over the D-ring 402 bar portion 404 to ensure the D-ring 402 remains in the desired position relative to the wear pad 407. An elastic strap 410 is inserted through the slot 406 of the D-ring 402 and operatively connected to the top of the dorsal pad 401 to urge the D-ring 402 in an upright position. In other words, the elastic strap 410 is secured between the dorsal pad 401 and the D-ring 402. The elastic strap 410 could be a woven strap having an elastic stretch of 100 to 200%. It could also include a sewn or otherwise fabricated stop 410a operatively connected to the end(s) of the elastic strap 410 and secured at its end(s) by passing the end(s) of the elastic strap 410 through a slot 415 in the dorsal pad 401 as shown, a slot 406 in the D-ring 402, or by sewing the elastic strap 410 directly to the connecting component. In operation, the first strap 408 is inserted through the top of slot 411a, through the bottom of slot 412, through the slot 405 of the D-ring 402 (under the bridges 407c and over the bar protector 407a of the wear pad 407), through the top of slot 413, and through the bottom of slot 414a. The dorsal pad 401 separates the strap 408 into left shoulder strap 408a and right back strap 408b. The second strap 409 is inserted through the top of slot 411b, through the bottom of slot 412, through the slot 405 of the D-ring 402 (under the bridges 407c and over the bar protector 407a of the wear pad 407), through the top of slot 413, and through the bottom of slot 414b. The dorsal pad 401 separates the strap 409 into right shoulder strap 409a and left back strap 409b. The straps 408 and 409 preferably overlap and criss-cross in divergent fashion through the dorsal pad 401. FIGS. 22 and 23 show a preferred embodiment dorsal D-ring pad assembly 500 including a dorsal pad 501, a D-ring 502, and a wear pad frame 507. The dorsal pad 501 is similarly configured and arranged as the dorsal pad 321 and dorsal pad 401, and straps 508 and 509 are similarly routed therethrough. The D-ring 502 includes a ring portion 503, a bar portion 504, and slots 505 and 506. The harness straps are inserted through slot 505, and an elastic strap 510 is inserted through the slots 505 and 506. Slot 506 is an additional slot than is not typically included in a D-ring but is used so the elastic strap 510 does not interfere with ring portion 503. The wear pad frame 507 includes two halves 507a and 507b joined by rivets 511 or shear members which could be separate components or incorporated into the frame 507. The frame 507 is generally the shape of the bottom portion of the D-ring 502 from the bottom of the ring portion 503 to the bottom of the bar portion 504. The frame 507 includes a slot corresponding with the slot 505 and allows for access to the slot 506 of the D-ring 502. The rivets 511 are inserted through apertures 512 in the wear pad frame 507 proximate the top of the wear pad frame 507. The wear pad frame 507 protects the webbing of the harness straps 508 and 509 along the bottom and the side edges of the D-ring 502 proximate the bar portion 504 and slot 505. An elastic strap 510 is inserted through the slot 506 and operatively connected to the top of the dorsal pad 501 to urge the D-ring 502 in an upright position. In other words, the elastic strap 510 is secured between the dorsal pad 501 and the D-ring 502. The elastic strap 510 could be a woven strap having an elastic stretch of 100 to 200%. It could also include a plastic button or otherwise fabricated stop 510a operatively connected to the end(s) of the elastic strap 510 and secured at its end(s) by passing the end(s) of the elastic strap 510 through a slot 515 in the dorsal pad 501 as shown, a slot 506 in the D-ring 502, or by sewing the elastic strap 510 directly to the connecting component. The dorsal D-ring pad assembly 500 could also include a fall and/or impact indicator. The wear pad frame 507 could include an ink filled pellet indicator 513, as shown in FIG. 24, or the D-ring 502 could include an impact indicator mark or flag 514, as shown in FIG. 25. The indicators 513 and 514 provide visual indication that the safety harness has been subjected to at least approximately 500 to 600 pounds of force. In addition, when the safety harness is subjected to an impact load of at least approximately 500 to 600 pounds of force, the rivets 511 could fracture and indication of the impact would be determined by the absence of the heads on the rivets 511, the wear pad frame 507 sliding relative to the D-ring 502 (possibly about {fraction (3/16)} inch) revealing an indicator mark or flag on the D-ring 514, the separation of the wear pad frame 507 into two separate halves 507a and 507b, and/or the bursting of an ink filled pellet indicator 513 which would stain the harness webbing. The change in appearance would provide visual indication that the D-ring was subjected to a force of an impact. FIG. 26 shows a preferred embodiment dorsal D-ring pad assembly 600 including a dorsal pad 601, a D-ring 602, and a wear pad 606. The dorsal pad 601, as shown in FIG. 28, is preferably an upside down pentagon shaped plate member and includes a first slot 612 and a second slot 614, through which straps of a harness pass, with an opening 613 therebetween. The D-ring 602, as shown in FIG. 27, includes a ring portion 603, a bar portion 604, and a slot 605. A spring 610 is coiled around the bar portion 604 of the D-ring 602. A first end 611a of the spring 610 extends downward from the bar portion 604, and a second end 611b of the spring 610 is wrapped around the side of the bar portion 604. The first end 611a provides the force required to urge the D-ring 602 in an upright position, and the second end 611b secures the spring 610 to the D-ring 602. The wear pad 606, as shown in FIG. 29, is a U-shaped member having a curved base portion 607, a first lip 608a, a second lip 608b, and a cavity 609 within the curved base portion 607. The first lip 608a extends upward from the curved base portion 607, and the second lip 608b extends downward from the curved base portion 607. The second lip 608b is preferably longer in length than the first lip 608a. In operation, bar portion 604 of the D-ring 602 including the spring 610 is inserted into the cavity 609 of the wear pad 606 with the first end 611a of the spring 610 facing outward from the wear pad 606, as shown in FIG. 26. The second lip 608b of the wear pad 606 is inserted into the opening 613 and a downward force is exerted upon the curved base portion 607 to insert the first lip 608a into the opening 613 thereby securing the wear pad 606 to the dorsal pad 601. The first end 611a of the spring 610 is positioned between the D-ring 602 and the dorsal pad 601 and keeps the D-ring 602 in an upward position. When the D-ring 602 is urged in a downward direction relative to the dorsal pad 601, the first end 611a pushes against the dorsal pad 601 to urge the D-ring 602 back into an upright position. The curved base portion 607 of the wear pad 606 keeps the bar portion 604 of the D-ring 602 from contacting the harness straps thereby reducing wear on the harness straps. A ledge could also be provided along the top edges of the curved base portion 607 to prevent possible contact of the sides of the D-ring 602 with the harness straps. FIGS. 30-33 show a dorsal D-ring wear pad assembly 700 including a D-ring 702, a D-ring connector 719, and a wear pad assembly 706. The D-ring 702 includes a ring portion 703, a bar portion 704, and a slot 705 between the ring portion 703 and the bar portion 704. The D-ring connector 719 includes a bar engaging portion 720, shown in FIGS. 34 and 35, which is generally cylindrical in shape and is configured and arranged to engage the bar portion 704 of the D-ring 702 within a longitudinal slot 723. When the D-ring 702 is engaged within the slot 723, the opening 723a of the slot 723 is preferably proximate the bottom of the D-ring 702. The bar engaging portion 720 includes ears 721a and 721b extending upward from the ends on one side of the bar engaging portion 720. The ears 721a and 721b extend upward along the sides of the slot 705 on one side of the D-ring 702. The bar engaging portion 720 also includes a lateral slot 722 proximate the middle of the bar engaging portion 720. A bar 711 extends across the slot 722 proximate the top of the bar engaging portion 720. One end of a spring 716 is operatively connected to the bar 711 and the spring 716 fits within the slot 722. In addition, the bar engaging portion 720 could include tabs 715, which act as an impact indicator, extending into the slot 723. The wear pad assembly 706, shown in FIG. 36, includes a generally triangular base portion 707. The base portion 707 includes a front base 707a and a back base 707b, which are interconnected by a curved portion 708. The curved portion 708 is generally cylindrical and includes a longitudinal bore 709 and a lateral slot 710 proximate the middle of the curved portion 708. The curved portion 708 is configured and arranged to house the bar engaging portion 720 within the bore 709. The front base 707a and the back base 707b extend downward from the bottom of the curved portion 708 and each includes an aperture 714a and 714b, respectively, at the ends opposite the curved portion 708. The other end of the spring 716 is operatively connected proximate the aperture 714b with a fastener such as a nut 718 and a bolt 717 extending through apertures 714a and 714b. The nut 718 and the bolt 717 not only secure the other end of the spring 716 but also operatively connect the bases 707a and 707b. The back base 707b includes a channel 712 which extends downward from the slot 710 to the bottom of the back base 707b. The spring 716 is housed within the channel 712 and ribs 713 extending along the sides of the channel 712 protect the spring 716. In operation, the D-ring 702 is inserted into the slot 123 of the D-ring connector 719. The bases 707a and 707b of the wear pad assembly 706 are separated, one on either side of the D-ring connector 719, and the D-ring connector 719 is inserted into the bore 709. Then the spring 716, which has been connected to the bar 711, is placed within the channel 712 and connected to the end of the base 707b via the nut 718 and bolt 717 through apertures 714a and 714b to connect the bases 707a and 707b. The dorsal D-ring wear pad assembly 700 is then operatively connected to a safety harness, as illustrated in FIGS. 37 and 38. The safety harness includes a first strap 725a, a second strap 725b, and a third strap 725c. The first and second straps 725a and 725b are threaded through the slot 705 of the D-ring 702 and preferably overlap and criss-cross in divergent fashion to form the shoulder straps and legs straps of the harness. The third strap 725c is attached at one end to the back of strap 725a, threaded through the slot 705 of the D-ring 702 over the wear pad assembly 706, and then attached at the other end to the back of the strap 725b. Stitching 726 may be used to attach the third strap 725c to the straps 725a and 725b. When assembled, the D-ring 702 extends generally in an upward direction relative to the wear pad 706 thereby extending the spring 716. The D-ring 702 and the wear pad assembly 706 are kept in place between the loop of the third strap 725c and the stitching 726. When thus connected, the spring 716 urges the D-ring 702 in an upright position. When the D-ring 702 is pushed in a downward direction, the spring 716 is extended and because the spring 716 wants to contract, a constant force urges the D-ring 702 in an upright position. The curved portion 708 of the wear pad assembly 706 acts as a wear pad because as the D-ring 702 pivots, the curved portion 708 does not move with the D-ring 702. This prevents excess wear on the straps 725a and 725b. In addition, the spring 716 exerts constant force upon the D-ring 702 to ensure that the D-ring 702 remains in an upright position. Should a fall occur and/or a load is applied to the D-ring 702, the tabs 715 are crushed or collapse to expose a color under the ears 721a and 721b. The exposed color is an impact indicator visually indicating that the safety harness should be discarded. FIGS. 39 and 40 show a preferred embodiment dorsal D-ring pad assembly 800 including a dorsal pad 801, a D-ring 802, and a wear tube 807. The D-ring 802 includes a ring portion 803, a bar portion 804, a slot 805, and an intermediate portion 806. The bar portion 804 fits within a cavity in the wear tube 807. The dorsal pad 801 is similarly configured and arranged as the dorsal pad 321 and dorsal pads 401 and 501, and the harness straps 808 and 809 are similarly threaded therethrough, being inserted through slot 805 in the D-ring 802. The wear tube 807 is preferably a cylindrical tube member about the bar portion 804 of the D-ring 802 that protects the harness straps 808 and 809 along the bottom of the D-ring 802 proximate the bar portion 804. The wear tube 807 is positioned between the D-ring 802 and the straps 808 and 809 and because the D-ring 802 moves independently within the wear tube 807, the D-ring 802 does not rub against the straps 808 and 809. An elastic cord 812 interconnects the D-ring 802 and the dorsal pad 801 and urges the D-ring 802 in an upright position. The elastic cord 812 may be stretched to urge the D-ring 802 in a downward position, but the elastic cord 812 wants to contract to urge the D-ring 802 back into an upright position. A coupling 811 may be used to connect the elastic cord 812 to the D-ring 802, and a stop 813 may be used to connect the elastic cord 812 to the dorsal pad 801. For example, the coupling 811 could be a snap on member secured to the intermediate portion 806 of the D-ring 802. The elastic cord 812 could be inserted through an aperture 815 in the dorsal pad 801, and the stop 813 could be a knot or other fabricated securing member well known in the art. The elastic cord 812 is preferably woven or molded having an elastic stretch of 100 to 200%. An example of a mechanism for substantially holding a D-ring 910 in an upright receiving position is shown in FIGS. 41-43. A preferred embodiment D-ring clip and fall indicator 900 includes a dorsal pad 901 having clip members 902a and 902b. The dorsal pad 901 is similarly configured and arranged as the dorsal pad 321 and dorsal pads 401, 501, and 801, and the harness straps 916a and 916b are similarly threaded therethrough, being inserted through the strap opening 915 in the D-ring 910. The D-ring 910 includes a ring portion 911 and a bar portion 912 interconnected by connecting portions 913. The ring portion 911 includes a connector opening 914. A strap opening 915 is defined between the ring portion 911, the bar portion 912, and the connecting portions 913. An intermediate portion 918 divides the connector opening 914 and the strap opening 915. The harness straps 916a and 916b preferably criss-cross and overlap through the strap opening 915. The clip members 902a and 902b are preferably molded to the dorsal pad 901, as shown in FIGS. 42 and 43. The clip members 902a and 902b extend outward from the dorsal pad 901 to accommodate the width and the thickness of the D-ring 910 and then extend inward to hold the D-ring 910 in an upright receiving position, as shown in FIGS. 41 and 42. It is preferred to position the clip members 902a and 902b proximate the intermediate portion 918 as to not interfere with the operation of the D-ring 910 and the safety harness. Although one clip member could be used, it is preferred to have at least two clip members, at least one on each side of the D-ring 910. It is recognized that a biasing mechanism could also be used to substantially hold the D-ring in the upright receiving position. In operation, the D-ring 910 is held in an upright receiving position by the clip members 902a and 902b, as shown in FIG. 42. When the D-ring 910 has been subjected to a force, the D-ring 910 moves in a downward position thereby deflecting the clip members 902a and 902b outward, as shown in FIG. 43, and releasing the D-ring 910 from the clip members 902a and 902b. Because the D-ring 910 becomes disengaged by the clip members 902a and 902b and is no longer in an upright receiving position, this provides visual indication that the D-ring 910 has been subjected to a force or an impact. The D-ring could be placed in the first position again manually or by other suitable means. It is understood that any of these features may be interchanged among the different preferred embodiments to create variations thereof and such variations are within the scope of the present invention. The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a safety harness and components thereof. 2. Description of the Prior Art Various occupations place people in precarious positions at relatively dangerous heights thereby creating a need for fall-arresting safety apparatus. Among other things, such apparatus usually include a safety line interconnected between a support structure and a person working in proximity to the support structure. The safety line is typically secured to a full-body safety harness worn by the worker. Obviously, such a harness must be designed to remain secure about the worker in the event of a fall. In addition, the harness should arrest a person's fall in as safe a manner as possible, placing a minimal amount of strain on the person's body. Yet another design consideration is to minimize the extent to which people may consider the harness uncomfortable and/or cumbersome. In addition, there is a need for a more user-friendly safety harness. For example, it is often difficult and/or cumbersome to connect the safety harness to a safety line. Further, once a safety harness has been subjected to forces from a fall, the safety harness must be discarded. It is often difficult to determine whether a safety harness has been subjected to forces from a fall or an impact. | <SOH> SUMMARY OF THE INVENTION <EOH>In a preferred embodiment safety harness, the safety harness includes a first strap, a second strap, a D-ring, and a biasing mechanism. The D-ring is operatively connected to the straps and has a first position and a second position. The first position is an upright receiving position, and the second position is a connected operating position. The biasing mechanism is operatively connected to the D-ring, and the biasing mechanism urges the D-ring to the first position. In another preferred embodiment safety harness, the safety harness includes a first strap, a second strap, a D-ring, and an impact indicator. The D-ring is operatively connected to the straps, and the impact indicator is operatively connected to the D-ring. The impact indicator provides indication when the D-ring has been subjected to a force. In a preferred embodiment safety harness having a first strap and a second strap, a D-ring is operatively connected to the straps. The D-ring has a first position and a second position. The first position is an upright receiving position, and the second position is a connected operating position. The safety harness also includes means for urging the D-ring to the first position. In a preferred embodiment dorsal pad assembly for use with a safety harness having a first strap and a second strap, a D-ring is operatively connected to the straps. The D-ring has a first position and a second position. The first position is an upright receiving position, and the second position is a connected operating position. A biasing mechanism is operatively connected to the D-ring, and the biasing mechanism urging the D-ring to the first position. An impact indicator is operatively connected to the D-ring, and the impact indicator provides indication when the D-ring has been subjected to a force. In a preferred embodiment dorsal pad assembly for use with a safety harness including straps, a D-ring has a bar portion, a first position, and a second position. The first position is an upright receiving position, and the second position is a connected operating position. A D-ring clip has a cavity, and the bar portion of the D-ring is positioned within the cavity and is engaged by the D-ring clip. A dorsal pad has slots and a D-ring connector portion. The straps of the harness are routed through the slots, and the D-ring connector portion has a second cavity. The D-ring clip is positioned within the second cavity and is engaged by the dorsal pad. A biasing mechanism interconnects the D-ring clip and the dorsal pad, and the biasing mechanism applies a force on the D-ring clip thereby urging the D-ring to the first position. When the D-ring is placed in the second position, the biasing mechanism urges the D-ring to the first position. In a preferred embodiment method of securing a safety harness donned by a user to a connector of a safety device, a D-ring operatively connected to straps of the safety harness is constantly urged to an upright position relative to the user. The D-ring has a first position and a second position. The first position is an upright receiving position, and the second position is a connected operating position. The connector of the safety device is secured to the D-ring in the upright receiving position. In another preferred embodiment dorsal pad assembly for use with a safety harness having a first strap and a second strap, a D-ring is operatively connected to the straps and has a first position and a second position. The first position is an upright receiving position, and the second position is an impact indicator position. A mechanism is operatively connected to the dorsal pad assembly, and the mechanism substantially holds the D-ring in the first position and allows the D-ring to be in the second position when the D-ring has been subjected to a force. In another preferred embodiment dorsal pad assembly for use with a safety harness having a first strap and a second strap, a D-ring is operatively connected to the straps and has a first position and a second position. The first position is an upright receiving position, and the second position is an impact indicator position. The dorsal pad assembly also includes means for substantially holding the D-ring in the first position and allowing the D-ring to be in the second position when the D-ring has been subjected to a force. | 20040408 | 20060711 | 20050331 | 92135.0 | 1 | THOMPSON, HUGH B | DORSAL PAD ASSEMBLY FOR USE WITH A SAFETY HARNESS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,821,097 | ACCEPTED | Compressor | A compressor has at least three-rotors. A first compression path between first inlet and outlet ports is associated with interaction of the first and second rotors. A second compression path between second inlet and outlet ports is associated with interaction of the first and third rotors. At least partial independence of the ports permits the first and second inlet ports to be at a different pressure or the first and second outlet ports to be at a different pressure. Fully or partially separate circuits in a refrigeration or air conditioning system may be associated with the first and second compression paths. | 1. A compressor comprising: a housing; a first rotor held by the housing for rotation about a first axis; a second rotor held by the housing for rotation about a second axis; a third rotor held by the housing for rotation about a third axis; a first compression path having suction and discharge ends; and a second compression path, independent of the first compression path and having suction and discharge ends, wherein at least one of: the discharge end of the first compression path is at a different pressure than the discharge end of the second compression path; and the suction end of the first compression path is at a different pressure than the suction end of the second compression path. 2. The compressor of claim 1 wherein: the first compression path is associated with the first rotor and the second rotor; and the second compression path is associated with the first rotor and the third rotor. 3. A cooling system including the compressor of claim 1 and further comprising: at least one condenser; at least one expansion device; at least one evaporator; and a plurality of conduits coupling the compressor, the at least one condenser, the at least one expansion device, and the at least one evaporator so as to define first and second at least partially separate circuits respectively associated with the first and second compression paths. 4. The cooling system of claim 3 wherein: the discharge end of the first compression path is at the same pressure as the suction end of the second compression path. 5. The apparatus of claim 4 further comprising: a first condenser; a first expansion device; a first evaporator; and one or more first conduits coupling the first condenser, the first expansion device and the first evaporator to the housing to define a first flowpath from the discharge end of the second compression path to the suction end of the first compression path. 6. An apparatus comprising: a housing; a first rotor held within the housing for rotation about a first axis; a second rotor enmeshed with the first rotor and held within the housing for rotation about a second axis; and a third rotor enmeshed with the first rotor and held within the housing for rotation about a third axis, wherein: the housing comprises: a first surface cooperating with the first and second rotors to define a first inlet port; a second surface cooperating with the first and second rotors to define a first outlet port; a third surface cooperating with the first and third rotors to define a second inlet port; and a third surface cooperating with the first and third rotors to define a second outlet port; and at least one of: the first and second inlet ports are at a different pressure than each other; and the first and second outlet ports are at a different pressure than each other. 7. The apparatus of claim 6 further comprising: a first condenser; a first evaporator; one or more first conduits coupling the first condenser and the first evaporator to the housing to define a first flowpath from the first outlet port through the first evaporator and first condenser and to the first inlet port; a second condenser; a second evaporator; and one or more second conduits coupling the second condenser and the second evaporator to the housing to define a second flowpath from the second outlet port through the second evaporator and second condenser and to the second inlet port. 8. The apparatus of claim 6 wherein: the first outlet port is at the same pressure as the second inlet port. 9. The apparatus of claim 8 further comprising: a first condenser; a first expansion device; a first evaporator; and one or more first conduits coupling the first condenser, the first expansion device and the first evaporator to the housing to define a first flowpath from the second outlet port to the first inlet port. 10. The apparatus of claim 9 wherein: there are no economizer branches off the first flowpath. 11. The apparatus of claim 9 further comprising: an economizer heat exchanger having: a first leg along the first flowpath; and a second leg, in heat exchange relation with the first leg, the second leg being along a diversion flowpath from a location along the first flowpath between the first condenser and the first leg to join a second flowpath from the first outlet port to the second inlet port. 12. The apparatus of claim 6 wherein either: the first and second inlet ports are at like pressure; or the first and second outlet ports are at like pressure. 13. The apparatus of claim 6 wherein either: the first and second inlet ports form a common inlet port; or the first and second outlet ports form a common outlet port. 14. The apparatus of claim 6 wherein: the first rotor is a male rotor; and the second and third rotors are female rotors. 15. An apparatus comprising: a first rotor held for rotation in at least a first direction about a first axis; a second rotor enmeshed with the first rotor and held for rotation about a second axis; a third rotor enmeshed with the first rotor and held for rotation about a third axis; and means cooperating with the first, second, and third rotors for providing a first volume index associated with interaction of the first and second rotors when the first rotor is driven in the first direction; and a second volume index associated with interaction of the first and third rotors when the first rotor is driven in the first direction, the second volume index different from the first volume index. 16. The apparatus of claim 15 in combination with first and second refrigerant flows along non-intersecting first and second flowpaths through the apparatus. 17. The apparatus of claim 15 in combination with first and second refrigerant flows along first and second flowpaths through the apparatus intersecting at a suction side of the apparatus. 18. The apparatus of claim 15 in combination with first and second refrigerant flows along first and second flowpaths through the apparatus intersecting at a discharge side of the apparatus. | BACKGROUND OF THE INVENTION (1) Field of the Invention The invention relates to compressors, and more particularly to screw-type compressors. (2) Description of the Related Art Screw-type compressors are commonly used in air conditioning and refrigeration applications. In such a compressor, intermeshed male and female lobed rotors or screws are rotated about their axes to pump the working fluid (refrigerant) from a low pressure inlet end to a high pressure outlet end. During rotation, sequential lobes of the male rotor serve as pistons driving refrigerant downstream and compressing it within the space (compression pocket) between an adjacent pair of female rotor lobes and the housing. Likewise sequential lobes of the female rotor produce compression of refrigerant within a male rotor compression pocket between an adjacent pair of male rotor lobes and the housing. In one implementation, the male rotor is coaxial with an electric driving motor and is supported by bearings on inlet and outlet sides of its lobed working portion. There may be multiple female rotors engaged to a given male rotor or vice versa. With such a compressor, male and female compression pockets may also have multiple inlet and outlet ports. When a compression pocket is exposed to an inlet port, the refrigerant enters the pocket essentially at suction pressure. As the pocket continues to rotate, at some point during its rotation, the pocket is no longer in communication with the inlet port and the flow of refrigerant to the pocket is cut off. Typically the inlet port geometry is arranged in such a way that the flow of refrigerant is cut off at the time in the cycle when the pocket volume reaches its maximum value. Typically the inlet port geometry is such that both male and female compression pockets are cut off at the same time. The inlet port is typically a combination of an axial port and a radial port. After the inlet port is closed, the refrigerant is compressed as the pockets continue to rotate and their volume is reduced. At some point during the rotation, each compression pocket intersects the associated outlet port and the closed compression process terminates. Typically outlet port geometry is such that both male and female pockets are exposed to the outlet port at the same time. As with the inlet port, the outlet port is normally a combination of an axial port and a radial port. By combining axial and radial ports into one design configuration, the overall combined port area is increased, minimizing throttling losses associated with pressure drop through a finite port opening area. In an exemplary three-rotor configuration, the inlet and outlet ports are respectively formed at common inlet and outlet plenums. The compressor may be designed and sized for its intended use (e.g., to provide a given compression or volume index and operate at a given flow at a given speed or combination thereof). Different compressors or at least different components (rotors, motors, and the like) may be required for different uses. SUMMARY OF THE INVENTION One aspect of the invention involves an apparatus comprising: a first rotor enmeshed with second rotors. The rotors are held within a housing for rotation about respective first, second, and third axes. The housing has: a first surface cooperating with the first and second rotors to define a first inlet port; a second surface cooperating with the first and second rotors to define a first outlet port; a third surface cooperating with the first and third rotors to define a second inlet port; and a third surface cooperating with the first and third rotors to define a second outlet port. Either the first and second inlet ports are at a different pressure or the first and second outlet ports are at a different pressure. In various implementations, the apparatus may further include: a first condenser; a first evaporator; and one or more first conduits coupling the first condenser and the first evaporator to the housing to define a first flowpath from the first outlet port through the first evaporator and first condenser and to the first inlet port. The apparatus may further include: a second condenser; a second evaporator; and one or more second conduits coupling the second condenser and the second evaporator to the housing to define a second flowpath from the second outlet port through the second evaporator and second condenser and to the second inlet port. The first outlet port may be at the same pressure as the second inlet port. The apparatus of may further include a first condenser, a first expansion device, and a first evaporator. One or more first conduits may couple the first condenser, the first expansion device and the first evaporator to the housing to define a first flowpath from the second outlet port to the first inlet port. There may be no economizer branches off the first flowpath. There may be an economizer heat exchanger having a first leg along the first flowpath and a second leg, in heat exchange relation with the first leg. The second leg may be along a diversion flowpath from a location along the first flowpath between the first condenser and the first leg to join a second flowpath from the first outlet port to the second inlet port. Either the first and second inlet ports may form a common inlet port or the first and second outlet ports may form a common outlet port. Either the first and second inlet ports may be at like pressure or the first and second outlet ports may be at like pressure. The first rotor may be a male rotor and the second and third rotors may be female rotors Another aspect of the invention involves an apparatus comprising a first rotor enmeshed with second and third rotors. The rotors are held within a housing for rotation about respective first, second, and third axes. Means cooperate with the first, second, and third rotors for providing: a first volume index associated with interaction of the first and second rotors when the first rotor is driven in the first direction; and a second volume index associated with interaction of the first and third rotors when the first rotor is driven in the first direction. The second volume index is different from the first volume index. In various implementations, the apparatus may be combined with first and second refrigerant flows along non intersecting first and second flowpaths through the apparatus. T he apparatus may be combined with first and second refrigerant flows along first and second flowpaths through the apparatus intersecting at a suction side of the apparatus. The apparatus may be combined with first and second refrigerant flows along first and second flowpaths through the apparatus intersecting at a discharge side of the apparatus. The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial semi-schematic longitudinal cutaway sectional view of a compressor. FIG. 2 is a schematic view of a first system including a compressor according to principles of the invention. FIG. 3 is a schematic view of a second system including a compressor according to principles of the invention. FIG. 4 is a schematic view of a third system including a compressor according to principles of the invention. FIG. 5 is a schematic view of a fourth system including a compressor according to principles of the invention. FIG. 6 is a schematic view of a fifth system including a compressor according to principles of the invention. Like reference numbers and designations in the various drawings indicate like elements. DETAILED DESCRIPTION FIG. 1 shows a compressor 20 having a housing assembly 22 containing a motor 24 driving rotors 26, 27 and 28 having respective central longitudinal axes 500, 501 and 502. In the exemplary embodiment, the male rotor 26 is centrally positioned within the compressor and has a male lobed body or working portion 30 enmeshed with female lobed body or working portion 34; 35 of each female rotor 27; 28. Each rotor includes shaft portions (e.g., stubs 39, 40, 41, and 42, 43,44 unitarily formed with the associated working portion) extending from first and second ends of the associated working portion. Each of these shaft stubs is mounted to the housing by one or more bearing assemblies 50 for rotation about the associated rotor axis. In the exemplary embodiment, the motor 24 is an electric motor having a rotor and a stator. A portion of the first shaft stub 39 of the male rotor 26 extends within the stator and is secured thereto so as to permit the motor 24 to drive the male rotor 26 about the axis 500. When so driven in an operative first direction about the axis 500, the male rotor drives the female rotors in opposite directions about their axes 501 and 502. Surfaces of the housing combine with the enmeshed rotor bodies to define inlet and outlet ports to a two pairs of compression pockets: a first pair of male and female compression pockets formed by the housing, male rotor, and the first female rotor; and a second pair of male and female compression pockets formed by the housing, male rotor and the second female rotor. In each pair, one such pocket is located between a pair of adjacent lobes of each rotor associated rotor. Depending on the implementation, the ports may be radial, axial, or a hybrid of the two. FIG. 1 shows first and second radial inlet ports 46 and 47 and first and second radial outlet ports 48 and 49. The resulting enmeshed rotation of the rotor working portions tends to drive fluid from a first (inlet/suction) end to a second (outlet/discharge) end while compressing such fluid. This defines a downstream direction. According to the invention, the compression paths associated with two compression pockets do not meet at one or both of the inlet and outlet ends. In the exemplary embodiment, separate first and second inlet plenums 61 and 62 are respectively associated with the first and second pairs of compression pockets as are first and second outlet plenums 63 and 64. This may be achieved by a simple modification of the housing (e.g. a modification of an actual housing or a modification of the functional design thereof) of a conventional compressor to bifurcate one or both of an initially common suction port and an initially common discharge port. This modification may leave other components (e.g., rotors, motors, and the like) unchanged. More drastic modifications and clean sheet designs are also possible. Reuse of existing designs for varied applications can produce a variety of efficiencies (e.g., economies of scale). FIG. 2 shows a system 100 wherein the compressor 20 drives first and second independent refrigerant flows along first and second circuits/flowpaths 102 and 104. The first and second flowpaths each proceed downstream from the associated discharge plenum through a discharge conduit 106;108 to a condenser 110;112. From the condenser, the flowpaths proceed through an intermediate conduit 114;116 in which a thermostatic expansion valve (TXV) 118;120 is located to an evaporator 122;124. From the evaporator, the flowpaths proceed through a suction/return conduit 126;128 to the associated inlet plenum. In normal operation, the first and second flowpaths are separate (except for incidental leakage). Such a configuration may allow one compressor and associated hardware to replace two. This causes certain direct efficiencies and indirect efficiencies (e.g., associating a larger number of uses with a given basic compressor configuration). Alternative implementations may involve flowpaths that intersect at one or more individual points or overlap. FIG. 3 shows a system 150 wherein the compressor 20 drives first and second refrigerant flows along first and second circuits/flowpaths 152 and 154 that have a common upstream length and separate downstream lengths. The outlet plenums may be merged in the housing (e.g., as a single common outlet plenum) or by a T/Y-fitting in the discharge conduit 156. The combined first and second flowpaths proceed downstream through the discharge conduit to a single common condenser 158. From the condenser, the combined flowpaths proceed through the trunk of an intermediate conduit 160 which has a T/Y-fitting to separate into a first and second branches to separate the flowpaths. A TXV 162;164 is located in each branch and the associated flowpath proceeds downstream therefrom to an evaporator 166;168. From the evaporator, the flowpaths proceed through a suction/return conduit 170;172 to the associated inlet plenum. FIG. 4 shows a system 200 that may be constructed similarly to the system 150 but has first and second circuits/flowpaths 202 and 204 that have a common downstream length with a common evaporator 206 and separate upstream lengths with separate condensers 208 and 210 and TXVs 212 and 214. FIG. 5 shows a system 250 that has a single flowpath 252 in which the two compression paths are in series. The flowpath proceeds downstream from the first outlet plenum through a conduit 254 to the second inlet plenum. From the second outlet plenum, the flowpath proceeds through a discharge conduit 256 to a condenser 258. From the condenser, the flowpath proceeds through an intermediate conduit 260 in which a TXV 262 is located to an evaporator 264. From the evaporator, the flowpath proceed through a suction/return conduit 266 to the first inlet plenum. In a variation on the basic two-stage system of FIG. 5, FIG. 6 shows a system 300 that has a flowpath 302 providing a selective diversion along a diversion path 304 passing within an ecomomizer heat exchanger (HE) 306. A discharge conduit 308, condenser 310, TXV 312, evaporator 314, and suction/return conduit 316 may be similar to corresponding elements of the system 250. The intermediate conduit 318 includes a portion 320 within the HE. A diversion conduit 322 branches from the intermediate conduit between the condenser and HE to define the diversion path 304. The diversion conduit includes a portion 324 within the HE in heat exchange relation (e.g., parallel flow, counterflow, or crossflow) with the portion 320. A diversion TXV 326 is located in the diversion conduit to control the diversion flow. The diversion conduit joins the conduit 334 that feedsback from the first outlet plenum to the second inlet plenum. One or more embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, additional features may be included as are known in the art or are subsequently developed. Accordingly, other embodiments are within the scope of the following claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>(1) Field of the Invention The invention relates to compressors, and more particularly to screw-type compressors. (2) Description of the Related Art Screw-type compressors are commonly used in air conditioning and refrigeration applications. In such a compressor, intermeshed male and female lobed rotors or screws are rotated about their axes to pump the working fluid (refrigerant) from a low pressure inlet end to a high pressure outlet end. During rotation, sequential lobes of the male rotor serve as pistons driving refrigerant downstream and compressing it within the space (compression pocket) between an adjacent pair of female rotor lobes and the housing. Likewise sequential lobes of the female rotor produce compression of refrigerant within a male rotor compression pocket between an adjacent pair of male rotor lobes and the housing. In one implementation, the male rotor is coaxial with an electric driving motor and is supported by bearings on inlet and outlet sides of its lobed working portion. There may be multiple female rotors engaged to a given male rotor or vice versa. With such a compressor, male and female compression pockets may also have multiple inlet and outlet ports. When a compression pocket is exposed to an inlet port, the refrigerant enters the pocket essentially at suction pressure. As the pocket continues to rotate, at some point during its rotation, the pocket is no longer in communication with the inlet port and the flow of refrigerant to the pocket is cut off. Typically the inlet port geometry is arranged in such a way that the flow of refrigerant is cut off at the time in the cycle when the pocket volume reaches its maximum value. Typically the inlet port geometry is such that both male and female compression pockets are cut off at the same time. The inlet port is typically a combination of an axial port and a radial port. After the inlet port is closed, the refrigerant is compressed as the pockets continue to rotate and their volume is reduced. At some point during the rotation, each compression pocket intersects the associated outlet port and the closed compression process terminates. Typically outlet port geometry is such that both male and female pockets are exposed to the outlet port at the same time. As with the inlet port, the outlet port is normally a combination of an axial port and a radial port. By combining axial and radial ports into one design configuration, the overall combined port area is increased, minimizing throttling losses associated with pressure drop through a finite port opening area. In an exemplary three-rotor configuration, the inlet and outlet ports are respectively formed at common inlet and outlet plenums. The compressor may be designed and sized for its intended use (e.g., to provide a given compression or volume index and operate at a given flow at a given speed or combination thereof). Different compressors or at least different components (rotors, motors, and the like) may be required for different uses. | <SOH> SUMMARY OF THE INVENTION <EOH>One aspect of the invention involves an apparatus comprising: a first rotor enmeshed with second rotors. The rotors are held within a housing for rotation about respective first, second, and third axes. The housing has: a first surface cooperating with the first and second rotors to define a first inlet port; a second surface cooperating with the first and second rotors to define a first outlet port; a third surface cooperating with the first and third rotors to define a second inlet port; and a third surface cooperating with the first and third rotors to define a second outlet port. Either the first and second inlet ports are at a different pressure or the first and second outlet ports are at a different pressure. In various implementations, the apparatus may further include: a first condenser; a first evaporator; and one or more first conduits coupling the first condenser and the first evaporator to the housing to define a first flowpath from the first outlet port through the first evaporator and first condenser and to the first inlet port. The apparatus may further include: a second condenser; a second evaporator; and one or more second conduits coupling the second condenser and the second evaporator to the housing to define a second flowpath from the second outlet port through the second evaporator and second condenser and to the second inlet port. The first outlet port may be at the same pressure as the second inlet port. The apparatus of may further include a first condenser, a first expansion device, and a first evaporator. One or more first conduits may couple the first condenser, the first expansion device and the first evaporator to the housing to define a first flowpath from the second outlet port to the first inlet port. There may be no economizer branches off the first flowpath. There may be an economizer heat exchanger having a first leg along the first flowpath and a second leg, in heat exchange relation with the first leg. The second leg may be along a diversion flowpath from a location along the first flowpath between the first condenser and the first leg to join a second flowpath from the first outlet port to the second inlet port. Either the first and second inlet ports may form a common inlet port or the first and second outlet ports may form a common outlet port. Either the first and second inlet ports may be at like pressure or the first and second outlet ports may be at like pressure. The first rotor may be a male rotor and the second and third rotors may be female rotors Another aspect of the invention involves an apparatus comprising a first rotor enmeshed with second and third rotors. The rotors are held within a housing for rotation about respective first, second, and third axes. Means cooperate with the first, second, and third rotors for providing: a first volume index associated with interaction of the first and second rotors when the first rotor is driven in the first direction; and a second volume index associated with interaction of the first and third rotors when the first rotor is driven in the first direction. The second volume index is different from the first volume index. In various implementations, the apparatus may be combined with first and second refrigerant flows along non intersecting first and second flowpaths through the apparatus. T he apparatus may be combined with first and second refrigerant flows along first and second flowpaths through the apparatus intersecting at a suction side of the apparatus. The apparatus may be combined with first and second refrigerant flows along first and second flowpaths through the apparatus intersecting at a discharge side of the apparatus. The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. | 20040408 | 20070220 | 20051013 | 68968.0 | 0 | JIANG, CHEN WEN | COMPRESSOR | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,821,134 | ACCEPTED | System and method for brand name gift card exchange | The present invention provides for exchanging a gift card. Data associated with a first gift card is provided. The data associated with the first gift card is validated. Either a money rebate associated with the first gift card, or a second gift card is selected. The first gift card is exchanged for either a money rebate or the second gift card. An exchange fee is generated by both the vendor associated with the gift card and the company performing the exchange. | 1. A system for exchanging a gift card, comprising: at least one consumer input device; a consumer transaction server coupled to the at least one consumer input device; a transaction exchange server, configured to exchange the gift card for an item of value, coupled to the consumer transaction server; and a vendor transaction server, configured to release funds as a function of the exchanged gift card. 2. The system of claim 1, further comprising an exchange database coupled to the transaction exchange server. 3. The system of claim 2, further comprising a data mining and query system coupled to the exchange database. 4. The system of claim 1, further comprising a printer coupled to the consumer transaction server. 5. The system of claim 1, wherein the consumer input device comprises a telephone. 6. The system of claim 1, wherein the consumer input device comprises a personal computer. 7. The system of claim 1, wherein the consumer input devices comprises a kiosk. 8. The system of claim 1, wherein the vendor transaction server is further employable to buy a second gift card with the released funds. 9. A method of exchanging a gift card, comprising: providing data associated with a first gift card; validating the data associated with the first gift card; selecting either a money rebate associated with the first gift card, or a second gift card; and exchanging the first gift card for either a money rebate or the second gift card. 10. The method of claim 9, wherein providing data further comprises providing a merchant name. 11. The method of claim 9, wherein providing data further comprises providing an account number. 12. The method of claim 9, further comprising charging a first service fee for issuing the money amount. 13. The method of claim 9, further comprising charging a second service fee issuing the second gift card. 14. The method of claim 9, wherein providing the data associated with the gift card occurs with employment of a kiosk. 15. The method of claim 9, wherein providing the data associated with the gift card occurs with employment of a personal computer. 16. The method of claim 9, further comprising releasing funds associated with the first gift card by a vendor. 17. The method of claim 16, further comprising charging a third service fee for releasing funds associated with the first gift card by the vendor. 18. The method of claim 9, further comprising issuing the money by mail. 19. The method of claim 9, further comprising correlating the exchange of the gift card with at least one other piece of data. 20. The method of claim 19, wherein the step of correlating consists of at least one of the group of the trade name of the associated second gift card, the time of the exchange, and the type of consumer transaction device. 21. A computer program product for exchanging a gift card, the computer program product having a medium with a computer program embodied thereon, the computer program comprising: computer code for providing data associated with a first gift card; computer code for validating the data associated with the first gift card; computer code for selecting either a money rebate associated with the first gift card, or a second gift card; and computer code for exchanging the first gift card for either a money rebate or the second gift card. 22. A processor for exchanging a gift card, the processor including a computer program comprising: computer code for providing data associated with a first gift card; computer code for validating the data associated with the first gift card; computer code for selecting either a money rebate associated with the first gift card, or a second gift card; and computer code for exchanging the first gift card for either a money rebate or the second gift card. | TECHNICAL FIELD The present invention relates generally to electronic commerce and, more particularly, to the exchange of gift cards. BACKGROUND Many consumers have received gift cards, also known as gift certificates, from different stores, especially franchises, for Christmas, birthdays, anniversaries, and so forth. Sometimes these gift cards are welcome, and sometimes they are for stores and shopping boutiques that the recipient/consumer does not wish to frequent. In many instances, these gift cards tend to “burn a hole” in the pocket of the consumer, as the consumer looks for a way to use the card, whether or not the consumer needs or desires anything from those particular stores. Furthermore, if these cards are redeemed for cash, they are typically redeemed at the store of the card issuer, necessitating an unwanted trip by the consumer. Therefore, there is a need to exchange or redeem gift cards in a manner that addresses at least some of the problems associated with conventional gift card redemptions or exchanges. SUMMARY OF THE INVENTION The present invention provides for exchanging a gift card. Data associated with a first gift card is provided. The data associated with the first gift card is validated. Either a money rebate associated with the first gift card, or a second gift card is selected. The first gift card is exchanged for either a money rebate or the second gift card. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following Detailed Description taken in conjunction with the accompanying drawings, in which: FIG. 1 schematically depicts a system for electronically exchanging or redeeming gift cards; and FIGS. 2A and 2B illustrate a method for electronically exchanging or redeeming gift cards. DETAILED DESCRIPTION In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without such specific details. In other instances, well-known elements have been illustrated in schematic or block diagram form in order not to obscure the present invention in unnecessary detail. Additionally, for the most part, details concerning network communications, electromagnetic signaling techniques, and the like, have been omitted inasmuch as such details are not considered necessary to obtain a complete understanding of the present invention, and are considered to be within the understanding of persons of ordinary skill in the relevant art. In the remainder of this description, a processing unit (PU) may be a sole processor of computations in a device. In such a situation, the PU is typically referred to as an MPU (main processing unit). The processing unit may also be one of many processing units that share the computational load according to some methodology or algorithm developed for a given computational device. For the remainder of this description, all references to processors shall use the term MPU whether the MPU is the sole computational element in the device or whether the MPU is sharing the computational element with other MPUs, unless otherwise indicated. It is further noted that, unless indicated otherwise, all functions described herein may be performed in either hardware or software, or some combination thereof. In a preferred embodiment, however, the functions are performed by a processor, such as a computer or an electronic data processor, in accordance with code, such as computer program code, software, and/or integrated circuits that are coded to perform such functions, unless indicated otherwise. Turning to FIG. 1, disclosed a system 100 in which gift card redemption can occur. The redemption can occur in the form of an exchange of a gift card for another gift card, or the exchange of a gift card for money. The gift card transaction typically occurs through an electronic or optical medium, such as through accessing the Internet, DTMF telephone signals, information entered into an ATM, and so on. In a further embodiment, the gift card for one store can be exchanged for the gift card of another store. This also typically occurs through an electronic medium, such as through accessing the Internet, DTMF telephone signals, information entered into an ATM, and so on. The system 100 generally incorporates “business to business” (B2B) and “business to consumer” (B2C) technologies to provide the business participants of the B2B with new marketing opportunities, and provides consumers with new customer satisfaction services. Generally, the B2B exchange will either instigate the partial refund of a gift card, for a fee, or the B2B exchange will issue another gift card for a participating vendor, minus a transaction fee. In the system 100, a plurality of consumer personal computers (PCs) 107 are employed by consumers 114. Alternatively, the consumers 114 can use a phone 105. The PCs are coupled to Internet 115, and the phone 105 is coupled to a voice response unit (VRU) 110. Both the Internet 115 and the VRU 110 are coupled to a consumer transaction server (CTS) 120. The transaction exchange server (TES) 140 is coupled to a vendor transaction server (VTS) 145, an exchange database 150, and Federal Reserve Electronic Funds Transfer (EFT) 165. The Internet 115 is further coupled to a plurality of vendor servers. The exchange database 150 is coupled to a data mining and query system 170. The federal EFT 165 is coupled to a plurality of consumer banks 175, 180. The system 100 can work substantially as follows. The consumer 114 can either phone or interact with the Internet through consumer PC's 107 or through the employment of a Kiosk/ATM machine in a store. The consumer 114 wishes to either exchange the original gift card for another gift card, or have a check issued and mailed or otherwise have a credit issued to his account. The consumer 114 also inputs his or her checking or banking information and/or mailing address, or the name of another gift card brand for which the consumer 114 selects to have the present gift card swapped. The consumer transaction server 120 receives the consumer's request. The consumer transaction server 120 forwards the request to the transaction exchange server 140, which accesses the exchange database 150 to determine whether the card brand type is a valid card brand type (that is, whether it is supported, such as a “Borders Bookstore” or “WalMart” card). The transaction exchange server 140 accesses the vendor transaction server 145 to verify that a card to be exchanged is individually a valid card, that is, whether it has a valid identification number. If it is valid, the vendor transaction server 145 releases the equivalent of the value of the card, minus a transaction fee, to the transaction exchange server 140. The transactional exchange server 140 can either request that the Federal Reserve EFT 165 transfer funds from the vendor banks 180 to the consumer banks 175. Alternatively, the server 140 can order a printer 125 to issue a check 130 to be sent through the US mail 135 to the consumer. Alternatively, a replacement card 127 can be sent through the US mail 135. In the system 100, the vendor transaction server 145, when allowing its card to be exchanged or cashed, would typically charge a fee for this, for instance 2% of the face value of the card. Then, the transaction exchange server 140 would charge an additional fee, say 8% of the face gift card amount, to send a check directly to the consumer, or 6% to exchange the original gift card for another gift card. The exchange of cards can happen as described in the following. The consumer 114 inputs the card to which he or she wishes to exchange, as well as the identification number on the original card. The transaction exchange server 140 gets the release of the credit from the original vendor, as described above. However, the transaction exchange server then authorizes another exchange to another card, minus a transaction fee for the exchange. For instance, a “Borders Book Store” could be exchanged for a “WalMart” card. The original vendor takes its cut, such as 2%, and credits the B2B exchange, such as at the TES 140, with the remaining amount of cash. The TES 140 then requests that the second vendor authorize a second gift card for its own brand. In a further embodiment, the exchanges made over the TES 140 could be monitored to aid in the determination of marketing trends. For instance, the exchange database 150 could record information pertinent to each gift card exchange, such as the brand name associated with the issued card, the amount of money of the gift card, the date that the card was issued, the date that the gift card was exchanged, the zip code of the consumer making the exchange, whether money or another gift card was requested in the exchange, and if so, what the brand name the card was switched to, and so on. Then, this information is requested or searched for by the data mining and query system 170 to look for patterns or other pieces of information of merit for use by marketers to determine the buying patterns/exchange patterns of consumers. In the system 100, this can be performed by the data mining and query system 170, but other means to perform data mining is within the scope of the present invention. Turning now to FIGS. 2A and 2B, illustrated is a method 200 for exchanging or refunding a gift-card. In step 210, the consumer decides that an exchange or refund is warranted. In step 220, the consumer accesses the B2B gift card exchange. This can be through the Internet, through DTMF tones, through an ATM machine, or other information exchange mechanism. In step 230, the consumer provides the merchant name on the gift card, and in step 240, the consumer provides the gift card account number on the gift card. In step 250, the system 100 queries the consumer as to whether he or she wishes to get cash, or another gift card. If the consumer chooses cash, the gift card account number is checked for validity in step 263. If the card is found to be not valid in step 271, then the flow stops in step 295. If the flow is valid, then credit is transferred from the named merchant to the “B2B Gift Card Exchange” in step 275, less a service fee originated by the vendor, such as a $2.00 fee. In step 281, a check, such as for $90 is printed for a consumer, or a credit of $90 is generated for the consumer. The B2B charges a transaction fee for converting the gift credit to a form usable by the consumer is generated, such as $8.00. In step 290, the check or credit for the refund is routed through the system. In step 293, the B2B exchange recognizes an $8.00 profit for a cash back option. Alternatively, a kiosk is used to either receive gift cards/gift card information, and/or to output a new gift card or the equivalent cash amount. Generally, the consumer provides the information as detailed above to the kiosk, and the kiosk can also issue either the cash, a check, credit a checking or savings account, or an alternative gift card. The method 200 stops in step 295. Alternatively, in step 250, if the consumer chooses an alternative gift card instead of the cash back option, the gift card account number is checked for validity in step 266. If the card is not valid in step 273, then the flow stops in step 295. In the flow is valid, then credit is transferred from the named merchant to the “B2B Gift Card Exchange” in step 277, less a service fee originated by the vendor, such as a $2.00 fee. In step 283, the selected second gift card for $92.00 is purchased on line, and is mailed or otherwise bestowed upon the consumer. (The B2B takes a service fee of $6.00, for example). Alternatively, the kiosk is used to either and/or receive gift cards/gift card information, and to output a new gift card or the equivalent cash amount. Generally, the consumer provides the information as detailed above to the kiosk, and the kiosk can also issue either the cash, a check, credit a checking or savings account, or an alternative gift card. In step 293, the B2B exchange recognizes a $6.00 profit for the exchange of gift card option. The method flow 200 stops in step 295. It is understood that the present invention can take many forms and embodiments. Accordingly, several variations may be made in the foregoing without departing from the spirit or the scope of the invention. The capabilities outlined herein allow for the possibility of a variety of programming models. This disclosure should not be read as preferring any particular programming model, but is instead directed to the underlying mechanisms on which these programming models can be built. Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention. | <SOH> BACKGROUND <EOH>Many consumers have received gift cards, also known as gift certificates, from different stores, especially franchises, for Christmas, birthdays, anniversaries, and so forth. Sometimes these gift cards are welcome, and sometimes they are for stores and shopping boutiques that the recipient/consumer does not wish to frequent. In many instances, these gift cards tend to “burn a hole” in the pocket of the consumer, as the consumer looks for a way to use the card, whether or not the consumer needs or desires anything from those particular stores. Furthermore, if these cards are redeemed for cash, they are typically redeemed at the store of the card issuer, necessitating an unwanted trip by the consumer. Therefore, there is a need to exchange or redeem gift cards in a manner that addresses at least some of the problems associated with conventional gift card redemptions or exchanges. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides for exchanging a gift card. Data associated with a first gift card is provided. The data associated with the first gift card is validated. Either a money rebate associated with the first gift card, or a second gift card is selected. The first gift card is exchanged for either a money rebate or the second gift card. | 20040408 | 20090224 | 20051013 | 85010.0 | 3 | FRECH, KARL D | SYSTEM AND METHOD FOR BRAND NAME GIFT CARD EXCHANGE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,821,146 | ACCEPTED | Detecting incorrect versions of files | A method, apparatus, system, and signal-bearing medium that in an embodiment issue a warning if a file to be used is an older version. In an embodiment, the warning includes an identification of the location of a newer version of the file. In an embodiment, the file is a class, and the old and new versions are found using a classpath, but in other embodiments any type of file or other object may be used. In this way, the use of incorrect versions of files may be detected and avoided. | 1. A method comprising: determining whether a first file to be used is an incorrect version; and if the determining is true, issuing a warning. 2. The method of claim 1, wherein the determining comprises: searching for a second file later in a classpath from the first file, wherein the second file is an earlier version than the first file. 3. The method of claim 1, wherein the issuing further comprises: providing an identification of a location of a newer version of the first file. 4. The method of claim 1, wherein the determining further comprises: determining whether a second file is owned by a user doing debug and the first file is not owned by the user doing debug, wherein the second file is later in a classpath than the first file. 5. An apparatus comprising: means for finding a first class in a first directory specified in a classpath; means for finding a second class in a second directory, wherein the second directory is later in the classpath than the first directory; and means for determining whether the second class is a newer version of the first class. 6. The apparatus of claim 5, further comprising: means for issuing a warning if the means for determining is true. 7. The apparatus of claim 5, further comprising: mean for deciding whether the second class is owned by a user doing debug and the first class is not owned by the user doing debug. 8. The apparatus of claim 7, further comprising: means for issuing a warning if the means for deciding is true. 9. A signal-bearing medium encoded with instructions, wherein the instructions when executed comprise: finding a first class in a first directory specified in a classpath; finding a second class in a second directory, wherein the second directory is later in the classpath than the first directory; determining whether the second class is a newer version of the first class; and issuing a warning if the determining is true. 10. The signal-bearing medium of claim 9, further comprising: deciding whether the second class is owned by a user doing debug and the first class is not owned by the user doing debug. 11. The signal-bearing medium of claim 10, further comprising: issuing the warning if the deciding is true. 12. The signal-bearing medium of claim 9, further comprising: saving a reason for the warning. 13. A computer system comprising: a processor; and memory encoded with instructions, wherein the instructions when executed on the processor comprise: finding a first class in a first directory specified in a classpath, finding a second class in a second directory, wherein the second directory is later in the classpath than the first directory, and deciding whether the second class is owned by a user doing debug and the first class is not owned by the user doing debug. 14. The computer system of claim 13, wherein the instructions further comprise: issuing a warning if the deciding is true. 15. The computer system of claim 14, wherein the issuing further comprises: providing an identification of the second directory. 16. The computer system of claim 13, wherein the instructions further comprise: determining whether the second class is a newer version of the first class; and issuing a warning if the determining is true. 17. A method of configuring a computer, wherein the method comprises: configuring the computer to determine whether a file to be used is an older version; and configuring the computer to issue a warning if the determining is true. 18. The method of claim 17, further comprising: configuring the computer to search for a newer version of the file later in a classpath from the older version. 19. The method of claim 17, wherein the warning further comprises: an identification of a location of a newer version of the file. 20. The method of claim 17, wherein the file comprises a class. | FIELD An embodiment of the invention generally relates to computer software. In particular, an embodiment of the invention generally relates to detecting incorrect versions of files. BACKGROUND The development of the EDVAC computer system of 1948 is often cited as the beginning of the computer era. Since that time, computer systems have evolved into extremely sophisticated devices, and computer systems may be found in many different settings. Computer systems typically include a combination of hardware (such as semiconductors, integrated circuits, programmable logic devices, programmable gate arrays, and circuit boards) and software, also known as computer programs. As advances in semiconductor processing and computer architecture push the performance of the computer hardware higher, more sophisticated and complex computer software has evolved to take advantage of the higher performance of the hardware, resulting in computer systems today that are much more powerful than just a few years ago. As the sophistication and complexity of computer software increase, the more difficult the software is to debug. Bugs are problems, faults, or errors in a computer program. Locating, analyzing, and correcting suspected faults in a computer program is a process known as “debugging.” Typically, a programmer uses another computer program commonly known as a “debugger” to debug a program under development. Conventional debuggers typically support two primary operations to assist a computer programmer. A first operation supported by conventional debuggers is a “step” function, which permits a computer programmer to process instructions (also known as “statements”) in a computer program one-by-one and see the results upon completion of each instruction. While the step operation provides a programmer with a large amount of information about a program during its execution, stepping through hundreds or thousands of program instructions can be extremely tedious and time consuming and may require a programmer to step through many program instructions that are known to be error-free before a set of instructions to be analyzed are executed. To address this difficulty, a second operation supported by conventional debuggers is a breakpoint operation, which permits a computer programmer to identify with a breakpoint a precise instruction for which it is desired to halt execution of a computer program during execution. As a result, when a computer program is executed by a debugger, the program executes in a normal fashion until a breakpoint is reached. The debugger then stops execution of the program and displays the results of the program to the programmer for analysis. Typically, step operations and breakpoints are used together to simplify the debugging process. Specifically, a common debugging operation is to set a breakpoint at the beginning of a desired set of instructions to be analyzed and then begin executing the program. Once the breakpoint is reached, the debugger halts the program, and the programmer then steps through the desired set of instructions line-by-line using the step operation. Consequently, a programmer is able to more quickly isolate and analyze a particular set of instructions without needing to step through irrelevant portions of a computer program. Computer programs being debugged are either compiled for execution by a compiler or executed by an interpreter. One example of an interpreter is the Java Virtual Machine (JVM), which employs a class loader to load classes used by the program being debugged on an as-needed basis. The classpath tells the class loader where to find third-party and user-defined classes. Classpath entries may be directories that contain classes not in a package, the package root directory for classes in a package, or archive files (e.g. .zip or jar files) that contain classes. The class loader loads classes in the order they appear in the classpath. For example, starting with the first classpath entry, the class loader visits each specified directory or archive file attempting to find the class to load. The first class found with the proper name is loaded, and any remaining classpath entries are ignored. The classpath can become a source of great frustration and annoyance for the user because as the number of dependent third-party and user-defined classes increases for the program being debugged, the classpath becomes a dumping ground for every conceivable directory and archive file, and the risk becomes greater that the class contains duplicate class entries. Thus, the user can experience great difficulty in determining which class the class loader will load first. For example, the user may append a directory to the classpath in attempt to get the latest version of a class loaded into the program being debugged, but the user may be unaware that another version of the class is located in a directory of higher precedence in the classpath. Without a better way to handle classpaths, the debugging process will continue to be a difficult and time-consuming task, which delays the introduction of software products and increases their costs. Although the aforementioned problems have been described in the context of the Java class loader and programs under debug, they can occur in any compiler or interpreter, in any type of computer language, and in non-debug environments as well as in debug environments. SUMMARY A method, apparatus, system, and signal-bearing medium are provided that in an embodiment issue a warning if a file to be used is an older version. In an embodiment, the warning includes an identification of the location of a newer version of the file. In an embodiment, the file is a class, and the old and new versions are found using a classpath, but in other embodiments any type of file or other object may be used. In this way, the use of incorrect versions of files may be detected and avoided. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 depicts a block diagram of an example system for implementing an embodiment of the invention. FIG. 2 depicts a pictorial representation of an example user interface for accessing a classpath, according to an embodiment of the invention. FIG. 3 depicts a pictorial representation of an example user interface for a debug controller, according to an embodiment of the invention. FIG. 4 depicts a pictorial representation of an example user interface for a debugger when providing a notification of a possible classpath error, according to an embodiment of the invention. FIG. 5A depicts a flowchart of example processing for a debug controller, according to an embodiment of the invention. FIG. 5B depicts a flowchart of further example processing for the debug controller, according to an embodiment of the invention. DETAILED DESCRIPTION In an embodiment, a debug controller warns the user if a file to be used is an old version and a newer version is available. The warning may include an identification of the location of the newer version of the file. In an embodiment, the file is a class, and the old and new versions are found using a classpath, but in other embodiments any type of file or other object may be used. In this way, the use of incorrect versions of files may be detected and avoided. Referring to the Drawing, wherein like numbers denote like parts throughout the several views, FIG. 1 depicts a high-level block diagram representation of a computer system 100, according to an embodiment of the present invention. The major components of the computer system 100 include one or more processors 101, a main memory 102, a terminal interface 111, a storage interface 112, an I/O (Input/Output) device interface 113, and communications/network interfaces 114, all of which are coupled for inter-component communication via a memory bus 103, an I/O bus 104, and an I/O bus interface unit 105. The computer system 100 contains one or more general-purpose programmable central processing units (CPUs) 101A, 101B, 101C, and 101D, herein generically referred to as the processor 101. In an embodiment, the computer system 100 contains multiple processors typical of a relatively large system; however, in another embodiment the computer system 100 may alternatively be a single CPU system. Each processor 101 executes instructions stored in the main memory 102 and may include one or more levels of on-board cache. The main memory 102 is a random-access semiconductor memory for storing data and programs. The main memory 102 is conceptually a single monolithic entity, but in other embodiments the main memory 102 is a more complex arrangement, such as a hierarchy of caches and other memory devices. For example, memory may exist in multiple levels of caches, and these caches may be further divided by function, so that one cache holds instructions while another holds non-instruction data, which is used by the processor or processors. Memory may further be distributed and associated with different CPUs or sets of CPUs, as is known in any of various so-called non-uniform memory access (NUMA) computer architectures. The memory 102 includes a debug controller 168 and a program 172. Although the debug controller 168 and the program 172 are illustrated as being contained within the memory 102 in the computer system 100, in other embodiments some or all of them may be on different computer systems and may be accessed remotely, e.g., via the network 130. The computer system 100 may use virtual addressing mechanisms that allow the programs of the computer system 100 to behave as if they only have access to a large, single storage entity instead of access to multiple, smaller storage entities. Thus, while the debug controller 168 and the program 172 are illustrated as residing in the memory 102, these elements are not necessarily all completely contained in the same storage device at the same time. The debug controller 168 is used to debug the program 172. The debug controller 168 includes a classpath controller 170. In another embodiment, the classpath controller 170 is separate from the debug controller 168. In another embodiment, the classpath controller 170 is implemented as a class loader or as a portion of a class loader that loads classes that may be used by the program 172. In an embodiment, the classpath controller 170 includes instructions capable of executing on the processor 101 or statements capable of being interpreted by instructions executing on the processor 101 to access or communicate with the user interfaces as further described below with reference to FIGS. 2, 3, and 4, and to perform the functions as further described below with reference to FIGS. 5A and 5B. In another embodiment, the classpath controller 170 may be implemented in microcode. In yet another embodiment, the classpath controller 170 may be implemented in hardware via logic gates and/or other appropriate hardware techniques, in lieu of or in addition to a processor-based system. In an embodiment, the program 172 includes instructions or statements capable of being interpreted or compiled to execute on the processor 101. The program 172 may be debugged by the debug controller 168. The memory bus 103 provides a data communication path for transferring data among the processors 101, the main memory 102, and the I/O bus interface unit 105. The I/O bus interface unit 105 is further coupled to the system I/O bus 104 for transferring data to and from the various I/O units. The I/O bus interface unit 105 communicates with multiple I/O interface units 111, 112, 113, and 114, which are also known as I/O processors (IOPs) or I/O adapters (IOAs), through the system I/O bus 104. The system I/O bus 104 may be, e.g., an industry standard PCI (Peripheral Component Interconnect) bus, or any other appropriate bus technology. The I/O interface units support communication with a variety of storage and I/O devices. For example, the terminal interface unit 111 supports the attachment of one or more user terminals 121, 122, 123, and 124. The storage interface unit 112 supports the attachment of one or more direct access storage devices (DASD) 125, 126, and 127 (which are typically rotating magnetic disk drive storage devices, although they could alternatively be other devices, including arrays of disk drives configured to appear as a single large storage device to a host). Various portions of the contents of the DASD 125, 126, and 127 may be loaded and stored from/to the memory 102 as needed. The I/O and other device interface 113 provides an interface to any of various other input/output devices or devices of other types. Two such devices, the printer 128 and the fax machine 129, are shown in the exemplary embodiment of FIG. 1, but in other embodiment many other such devices may exist, which may be of differing types. The network interface 114 provides one or more communications paths from the computer system 100 to other digital devices and computer systems; such paths may include, e.g., one or more networks 130. Although the memory bus 103 is shown in FIG. 1 as a relatively simple, single bus structure providing a direct communication path among the processors 101, the main memory 102, and the I/O bus interface 105, in fact the memory bus 103 may comprise multiple different buses or communication paths, which may be arranged in any of various forms, such as point-to-point links in hierarchical, star or web configurations, multiple hierarchical buses, parallel and redundant paths, etc. Furthermore, while the I/O bus interface 105 and the I/O bus 104 are shown as single respective units, the computer system 100 may in fact contain multiple I/O bus interface units 105 and/or multiple I/O buses 104. While multiple I/O interface units are shown, which separate the system I/O bus 104 from various communications paths running to the various I/O devices, in other embodiments some or all of the I/O devices are connected directly to one or more system I/O buses. The network 130 may be any suitable network or combination of networks and may support any appropriate protocol suitable for communication of data and/or code to/from the computer system 100. In various embodiments, the network 130 may represent a storage device or a combination of storage devices, either connected directly or indirectly to the computer system 100. In an embodiment, the network 130 may support Infiniband. In another embodiment, the network 130 may support wireless communications. In another embodiment, the network 130 may support hard-wired communications, such as a telephone line or cable. In another embodiment, the network 130 may support the Ethernet IEEE (Institute of Electrical and Electronics Engineers) 802.3x specification. In another embodiment, the network 130 may be the Internet and may support IP (Internet Protocol). In another embodiment, the network 130 may be a local area network (LAN) or a wide area network (WAN). In another embodiment, the network 130 may be a hotspot service provider network. In another embodiment, the network 130 may be an intranet. In another embodiment, the network 130 may be a GPRS (General Packet Radio Service) network. In another embodiment, the network 130 may be a FRS (Family Radio Service) network. In another embodiment, the network 130 may be any appropriate cellular data network or cell-based radio network technology. In another embodiment, the network 130 may be an IEEE 802.11B wireless network. In still another embodiment, the network 130 may be any suitable network or combination of networks. Although one network 130 is shown, in other embodiments any number of networks (of the same or different types) may be present. The computer system 100 depicted in FIG. 1 has multiple attached terminals 121, 122, 123, and 124, such as might be typical of a multi-user “mainframe” computer system. Typically, in such a case the actual number of attached devices is greater than those shown in FIG. 1, although the present invention is not limited to systems of any particular size. The computer system 100 may alternatively be a single-user system, typically containing only a single user display and keyboard input, or might be a server or similar device which has little or no direct user interface, but receives requests from other computer systems (clients). In other embodiments, the computer system 100 may be implemented as a personal computer, portable computer, laptop or notebook computer, PDA (Personal Digital Assistant), tablet computer, pocket computer, telephone, pager, automobile, teleconferencing system, appliance, or any other appropriate type of electronic device. It should be understood that FIG. 1 is intended to depict the representative major components of the computer system 100 at a high level, that individual components may have greater complexity that represented in FIG. 1, that components other than or in addition to those shown in FIG. 1 may be present, and that the number, type, and configuration of such components may vary. Several particular examples of such additional complexity or additional variations are disclosed herein; it being understood that these are by way of example only and are not necessarily the only such variations. The various software components illustrated in FIG. 1 and implementing various embodiments of the invention may be implemented in a number of manners, including using various computer software applications, routines, components, programs, objects, modules, data structures, etc., referred to hereinafter as “computer programs,” or simply “programs.” The computer programs typically comprise one or more instructions that are resident at various times in various memory and storage devices in the computer system 100, and that, when read and executed by one or more processors 101 in the computer system 100, cause the computer system 100 to perform the steps necessary to execute steps or elements embodying the various aspects of an embodiment of the invention. Moreover, while embodiments of the invention have and hereinafter will be described in the context of fully functioning computer systems, the various embodiments of the invention are capable of being distributed as a program product in a variety of forms, and the invention applies equally regardless of the particular type of signal-bearing medium used to actually carry out the distribution. The programs defining the functions of this embodiment may be delivered to the computer system 100 via a variety of signal-bearing media, which include, but are not limited to: (1) information permanently stored on a non-rewriteable storage medium, e.g., a read-only memory device attached to or within a computer system, such as a CD-ROM readable by a CD-ROM drive; (2) alterable information stored on a rewriteable storage medium, e.g., a hard disk drive (e.g., DASD 125, 126, or 127) or diskette; or (3) information conveyed to the computer system 100 by a communications medium, such as through a computer or a telephone network, e.g., the network 130, including wireless communications. Such signal-bearing media, when carrying machine-readable instructions that direct the functions of the present invention, represent embodiments of the present invention. In addition, various programs described hereinafter may be identified based upon the application for which they are implemented in a specific embodiment of the invention. But, any particular program nomenclature that follows is used merely for convenience, and thus embodiments of the invention should not be limited to use solely in any specific application identified and/or implied by such nomenclature. The exemplary environments illustrated in FIG. 1 are not intended to limit the present invention. Indeed, other alternative hardware and/or software environments may be used without departing from the scope of the invention. FIG. 2 depicts a pictorial representation of an example user interface 200 for accessing a classpath, according to an embodiment of the invention. The user interface 200 includes a user variables dialog 205 and a system variables dialog 210. One of the system variables is a classpath 215. The classpath 215 includes any number of entries that specify to the classpath controller 170 the location or locations to look for third-party and user-defined classes. In another embodiment, the classes are not restricted to third-party or user-defined classes and may be any type of class. In another embodiment, the class path is not restricted to classes and may specify the locations of an object, database, method, program, or any other type of file. Classpath entries may specify directories, archive files, or any other type of locations. The classpath controller 170 or other class loader loads classes, files, or objects in the order they appear in the classpath. For example, starting with the first classpath entry, the class loader visits each specified directory or archive file attempting to find the class, file, or other object to load. The first class found with the proper name is loaded, and any remaining classpath entries are ignored. In the example shown, the value of the first entry in the classpath 215 is “c:\debugger\jt400.jar,” which indicates the directory and jar file in which the classpath controller 170 will first search for classes. The data and user interface elements illustrated in FIG. 2 are exemplary only, and in other embodiments any appropriate data and user interface elements may be used. FIG. 3 depicts a pictorial representation of an example user interface 300 for the debug controller 168, according to an embodiment of the invention. The user interface 300 includes a classes under debug display 305 and a code under debug display 310. The classes under debug display 305 illustrates example classes that are used or are anticipated to be used by the program 172. The icon 320 indicates that the classpath controller 170 suspects that the associated class (“class b” in this example) may be the incorrect version. The classpath controller 170 determines that the associated class may be the incorrect version as further described below with reference to FIGS. 5A and 5B. In response to the user selecting the icon 320, or in response to any other appropriate command or stimulus, the debug controller 168 obtains further information regarding the warning from the classpath controller 170 and displays the user interface of FIG. 4, as further described below. The code under debug display 310 illustrates example contents of the program 172. FIG. 4 depicts a pictorial representation of an example user interface 400 for the debug controller 168 and the classpath controller 170 when providing a notification of a possible classpath error, according to an embodiment of the invention. In an embodiment, the debug controller 168 displays the user interface 400 in response to the selection of the icon 320 (FIG. 3), displays the user interface 400 automatically in response to detecting a class that may be the incorrect version, or displays the user interface 400 in response to any other appropriate command or stimulus. The user interface 400 includes a notification 425, which includes more information about the warning 320. The notification 425 indicates that a newer version of one of the classes displayed in the classes under debug display 305 was found. The notification 425 further includes the location of the newer version, which in this example is “/root/username.” Although the notification 425 is illustrated as being a popup window, in other embodiments, the notification may be implemented as message, whether text or oral, or any other appropriate notification. Although the warning 320 and the notification 425 are illustrated as being different elements in the user interfaces of FIGS. 4 and 5, in other embodiments, they may both be included in the same element. The data and user interface elements of FIG. 4 are exemplary only, and in other embodiments any appropriate data and user interface elements may be used. FIGS. 5A and 5B depict flowcharts of example processing for a classpath controller 170, according to an embodiment of the invention. Control begins at block 500. Control then continues to block 505 where the classpath controller 170 receives an event. Control then continues to block 510 where the classpath controller 170 determines whether the received event is an add class event, indicating that a class is being added to the execution of the program 172. If the determination at block 510 is true, then the event is an add class event, so control continues to block 515 where the classpath controller 170 begins a loop that is executed for each directory in the classpath 215 in order. So long as there are more directories remaining to be processed by the loop, control continues from block 515 to block 520 where the classpath controller 170 determines whether a class has been added to debug (see block 530, as further described below). If the determination at block 520 is false, then a class has not been added to debug, so control continues to block 525 where the classpath controller 170 determines whether the class being added by the add class event exists in the current directory being processed by the loop. If the determination at block 525 is true, then the class exists in the current directory, so control continues to block 530 where the classpath controller 170 adds the class to debug (which will cause the later determination at block 520 to be true). Control then returns to block 515, as previously described above. If the determination at block 525 is false, then the class does not exist in the current directory, so control returns to block 515, as previously described above. If the determination at block 520 is true, then the class has been added to debug, so control continues from block 520 to block 555 in FIG. 5B where the classpath controller 170 determines whether the current class exists in the current directory of the loop. If the determination at block 555 is true, then the current class exists in the current directory, so control continues to block 560 where the classpath controller 170 determines whether the current class is newer than the class that was previously added to debug (at block 530, as described above). If the determination at block 560 is true, then the current class is newer than the previously-added class, so control continues to block 565 where the classpath controller 170 turns on the warning indicator 320, as previously described above with reference to FIG. 3. In this way, the classpath controller 170 finds a class in a directory that is later in the classpath than the class that was previously added to debug. Control then continues to block 570 where the classpath controller 170 saves the reason for the warning indicator, which may be later displayed in the notification 425, as previously described above with reference to FIG. 4. Control then returns to block 515, as previously described above. If the determination at block 560 is false, then the current class is not newer than the previously-added class, so control continues to block 575 where the classpath controller 170 determines whether the current class is owned by the user doing the debug and the previously added class is not owned by the user doing the debug. If the determination at block 575 is true, then control continues to block 565, as previously described above. If the determination at block 575 is false, then control returns to block 515 in FIG. 5A, as previously described above. If the determination at block 555 is false, then the current class does not exist in the current directory, so control returns from block 555 to block 515 in FIG. 5A, as previously described above. When no more directories remain to be processed by the loop that begins at block 515, control returns from block 515 to block 505, as previously described above. If the determination at block 510 is false, then the received event was not an add class event, so control continues to block 535 where the classpath controller 170 processes other events. Control then returns to block 505, as previously described above. In the previous detailed description of exemplary embodiments of the invention, reference was made to the accompanying drawings (where like numbers represent like elements), which form a part hereof, and in which is shown by way of illustration specific exemplary embodiments in which the invention may be practiced. These embodiments were described in sufficient detail to enable those skilled in the art to practice the invention, but other embodiments may be utilized and logical, mechanical, electrical, and other changes may be made without departing from the scope of the present invention. Different instances of the word “embodiment” as used within this specification do not necessarily refer to the same embodiment, but they may. The previous detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims. In the previous description, numerous specific details were set forth to provide a thorough understanding of the invention. But, the invention may be practiced without these specific details. In other instances, well-known circuits, structures, and techniques have not been shown in detail in order not to obscure the invention. | <SOH> BACKGROUND <EOH>The development of the EDVAC computer system of 1948 is often cited as the beginning of the computer era. Since that time, computer systems have evolved into extremely sophisticated devices, and computer systems may be found in many different settings. Computer systems typically include a combination of hardware (such as semiconductors, integrated circuits, programmable logic devices, programmable gate arrays, and circuit boards) and software, also known as computer programs. As advances in semiconductor processing and computer architecture push the performance of the computer hardware higher, more sophisticated and complex computer software has evolved to take advantage of the higher performance of the hardware, resulting in computer systems today that are much more powerful than just a few years ago. As the sophistication and complexity of computer software increase, the more difficult the software is to debug. Bugs are problems, faults, or errors in a computer program. Locating, analyzing, and correcting suspected faults in a computer program is a process known as “debugging.” Typically, a programmer uses another computer program commonly known as a “debugger” to debug a program under development. Conventional debuggers typically support two primary operations to assist a computer programmer. A first operation supported by conventional debuggers is a “step” function, which permits a computer programmer to process instructions (also known as “statements”) in a computer program one-by-one and see the results upon completion of each instruction. While the step operation provides a programmer with a large amount of information about a program during its execution, stepping through hundreds or thousands of program instructions can be extremely tedious and time consuming and may require a programmer to step through many program instructions that are known to be error-free before a set of instructions to be analyzed are executed. To address this difficulty, a second operation supported by conventional debuggers is a breakpoint operation, which permits a computer programmer to identify with a breakpoint a precise instruction for which it is desired to halt execution of a computer program during execution. As a result, when a computer program is executed by a debugger, the program executes in a normal fashion until a breakpoint is reached. The debugger then stops execution of the program and displays the results of the program to the programmer for analysis. Typically, step operations and breakpoints are used together to simplify the debugging process. Specifically, a common debugging operation is to set a breakpoint at the beginning of a desired set of instructions to be analyzed and then begin executing the program. Once the breakpoint is reached, the debugger halts the program, and the programmer then steps through the desired set of instructions line-by-line using the step operation. Consequently, a programmer is able to more quickly isolate and analyze a particular set of instructions without needing to step through irrelevant portions of a computer program. Computer programs being debugged are either compiled for execution by a compiler or executed by an interpreter. One example of an interpreter is the Java Virtual Machine (JVM), which employs a class loader to load classes used by the program being debugged on an as-needed basis. The classpath tells the class loader where to find third-party and user-defined classes. Classpath entries may be directories that contain classes not in a package, the package root directory for classes in a package, or archive files (e.g. .zip or jar files) that contain classes. The class loader loads classes in the order they appear in the classpath. For example, starting with the first classpath entry, the class loader visits each specified directory or archive file attempting to find the class to load. The first class found with the proper name is loaded, and any remaining classpath entries are ignored. The classpath can become a source of great frustration and annoyance for the user because as the number of dependent third-party and user-defined classes increases for the program being debugged, the classpath becomes a dumping ground for every conceivable directory and archive file, and the risk becomes greater that the class contains duplicate class entries. Thus, the user can experience great difficulty in determining which class the class loader will load first. For example, the user may append a directory to the classpath in attempt to get the latest version of a class loaded into the program being debugged, but the user may be unaware that another version of the class is located in a directory of higher precedence in the classpath. Without a better way to handle classpaths, the debugging process will continue to be a difficult and time-consuming task, which delays the introduction of software products and increases their costs. Although the aforementioned problems have been described in the context of the Java class loader and programs under debug, they can occur in any compiler or interpreter, in any type of computer language, and in non-debug environments as well as in debug environments. | <SOH> SUMMARY <EOH>A method, apparatus, system, and signal-bearing medium are provided that in an embodiment issue a warning if a file to be used is an older version. In an embodiment, the warning includes an identification of the location of a newer version of the file. In an embodiment, the file is a class, and the old and new versions are found using a classpath, but in other embodiments any type of file or other object may be used. In this way, the use of incorrect versions of files may be detected and avoided. | 20040408 | 20120724 | 20051020 | 58496.0 | 0 | DAO, THUY CHAN | DETECTING INCORRECT VERSIONS OF FILES | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,821,197 | ACCEPTED | Thin film transistor, electronic device having the same, and method for manufacturing the same | An object of the present invention is to provide a method for manufacturing a thin film transistor which enables heat treatment aimed at improving characteristics of a gate insulating film such as lowering of an interface level or reduction in a fixed charge without causing a problem of misalignment in patterning due to expansion or shrinkage of glass. A method for manufacturing a thin film transistor of the present invention comprises the steps of heat-treating in a state where at least a gate insulating film is formed over a semiconductor film on which element isolation is not performed, simultaneously isolating the gate insulating film and the semiconductor film into an element structure, forming an insulating film covering a side face of an exposed semiconductor film, thereby preventing a short-circuit between the semiconductor film and a gate electrode. Expansion or shrinkage of a glass substrate during the heat treatment can be prevented from affecting misalignment in patterning since the gate insulating film and the semiconductor film are simultaneously processed into element shapes after the heat treatment. | 1. A thin film transistor comprising: an island-shaped semiconductor film and an island-shaped gate insulating film patterned by using the same photomask over an insulating substrate; a side wall made of an insulating material formed on a side face of the island-shaped semiconductor film; and a gate electrode formed over the island-shaped gate insulating film, characterized in that the gate electrode overlaps the side face of the island-shaped semiconductor film with the side wall therebetween. 2. A thin film transistor comprising: an island-shaped semiconductor film and an island-shaped gate insulating film patterned by using the same photomask over an insulating substrate; a side wall made of an insulating material formed on side faces of the island-shaped semiconductor film and the island-shaped gate insulating film; and a gate electrode formed over the island-shaped gate insulating film, characterized in that the gate electrode overlaps the side face of the island-shaped semiconductor film with the side wall therebetween. 3. A thin film transistor comprising: an island-shaped semiconductor film and an island-shaped gate insulating film patterned by using the same photomask on an insulating surface; and a gate electrode formed over the island-shaped gate insulating film, charcterized in that a side face of the island-shaped semiconductor film is insulated, and the gate electrode overlaps with the insulated side face of the island-shaped semiconductor film. 4. A thin film transistor comprising: an island-shaped semiconductor film and an island-shaped gate insulating film patterned by using the same photomask on an insulating substrate; an insulating film patterned to cover side faces of the island-shaped semiconductor film and the island-shaped gate insulating film and only a peripheral portion of a top face of the island-shaped gate insulating film; and a gate electrode formed over the island-shaped gate insulating film, characterized in that the gate electrode overlaps the side face of the island-shaped semiconductor film with the insulating film patterned to cover the side faces of the island-shaped semiconductor film and the island-shaped gate insulating film and only the peripheral portion of the top face of the island-shaped gate insulating film therebetween. 5. A thin film transistor according to claim 1 or 2, characterized in that effective thickness of the side wall in a portion covering the side face of the island-shaped semiconductor film in a direction perpendicular to the side face is set equal to or thicker than effective thickness of the island-shaped gate insulating film. 6. A thin film transistor according to claim 3, characterized by regarding effective thickness of an insulated portion of the side face of the island-shaped semiconductor film in a direction perpendicular to the side face as being set equal to or thicker than effective thickness of the island-shaped gate insulating film. 7. A thin film transistor according to claim 4, characterized by regarding effective thickness of the insulating film patterned to cover the side faces of the island-shaped semiconductor film and the island-shaped gate insulating film and only the peripheral portion of the top face of the island-shaped gate insulating film as being set equal to or thicker than effective thickness of the island-shaped gate insulating film. 8. A method for manufacturing a thin film transistor, characterized by comprising: forming a semiconductor film over an insulating substrate; forming a first insulating film over the semiconductor film; heat-treating the semiconductor film and the first insulating film; patterning the semiconductor film and the first insulating film into island shapes with the use of the same photomask after the heat treatment to form an island-shaped semiconductor film and an island-shaped gate insulating film; forming a second insulating film over the island-shaped gate insulating film; etching the second insulating film anisotropically to form a side wall covering side faces of the island-shaped semiconductor film and the island-shaped gate insulating film in self-aligned manner; forming a conductive film over the island-shaped gate insulating film after forming the side wall; and patterning the conductive film to form a gate electrode. 9. A method for manufacturing a thin film transistor, characterized by comprising: forming a semiconductor film over an insulating substrate; forming an insulating film over the semiconductor film; heat-treating the semiconductor film and the insulating film; patterning the semiconductor film and the insulating film into island shapes with the use of one resist mask after the heat treatment to form an island-shaped semiconductor film and an island-shaped gate insulating film; insulating a side face of the semiconductor film by adding oxygen or nitrogen to a side face of the island-shaped semiconductor film without removing the resist mask; forming a conductive film over the island-shaped gate insulating film; and patterning the conductive film to form a gate electrode. 10. A method for manufacturing a thin film transistor, characterized by comprising: forming a semiconductor film over an insulating substrate; forming a first insulating film over the semiconductor film; heat-treating the semiconductor film and the first insulating film; patterning the semiconductor film and the first insulating film into island shapes with the use of the same photomask after the heat treatment to form an island-shaped semiconductor film and an island-shaped gate insulating film; forming a second insulating film over the island-shaped gate insulating film; patterning the second insulating film to cover edge portions of the island-shaped semiconductor film and the island-shaped gate insulating film and only a peripheral portion of a top face of the island-shaped gate insulating film; forming a conductive film over the island-shaped gate insulating film; and patterning the conductive film to form a gate electrode. 11. A method for manufacturing a thin film transistor, characterized by comprising: forming a semiconductor film over an insulating substrate; forming a first insulating film over the semiconductor film; forming a first conductive film over the first insulating film; heat-treating the semiconductor film, the first insulating film, and the first conductive film, patterning the semiconductor film, the first insulating film, and the first conductive film into island shapes with the use of the same photomask after the heat treatment to form an island-shaped semiconductor film, an island-shaped gate insulating film, and a first island-shaped conductive film; forming a second insulating film over the first island-shaped conductive film; etching the second insulating film anisotropically to form a side wall covering side faces of the island-shaped semiconductor film, the island-shaped gate insulating film, and the first island-shaped conductive film in a self-aligned manner; forming a second conductive film over the first island-shaped conductive film after forming the side wall; and patterning the first island-shaped conductive film and the second conductive film to form a gate electrode. 12. A method for manufacturing a thin film transistor, characterized by comprising: forming a semiconductor film over an insulating substrate; forming an insulating film over the semiconductor film; forming a first conductive film over the insulating film; heat-treating the semiconductor film, the insulating film, and the first conductive film; patterning the semiconductor film, the insulating film, and the first conductive film into island shapes with the use of the same resist mask after the heat treatment to form an island-shaped semiconductor film, an island-shaped gate insulating film, and a first island-shaped conductive film; adding oxygen or nitrogen to a side face of the island-shaped semiconductor film without removing the resist mask to insulate a side face of the semiconductor film; forming a second conductive film over the first island-shaped conductive film; and patterning the first island-shaped conductive film and the second conductive film to form a gate electrode. 13. A method for manufacturing a thin film transistor, characterized by comprising: forming a semiconductor film over an insulating substrate; forming a first insulating film over the semiconductor film; forming a first conductive film over the insulating film; heat-treating the semiconductor film, the first insulating film, and the first conductive film; patterning the semiconductor film, the first insulating film, and the first conductive film into island shapes with the use of the same photomask after the heat treatment to form an island-shaped semiconductor film, an island-shaped gate insulating film, and a first island-shaped conductive film; forming a second insulating film over the first island-shaped conductive film; patterning the second insulating film to cover edge portions of the island-shaped semiconductor film, the island-shaped gate insulating film, and the first island-shaped conductive film and only a peripheral portion of a top face of the first island-shaped conductive film; forming a second conductive film over the island-shaped gate insulating film; and forming a gate electrode by patterning the first conductive film and the second conductive film. 14. A method for manufacturing a thin film transistor according to any one of claims 8, 10, 11 and 13, characterized in that the heat-treatment of the semiconductor film and the first insulating film is done at a temperature of from 600° C. to 800° C. 15. A method for manufacturing a thin film transistor according to claim 9 or 12, characterized in that the heat-treatment of the semiconductor film and the insulating film is done at a temperature of from 600° C. to 800° C. 16. A method for manufacturing a thin film transistor according to claim 14, characterized in that a strain point of the insulating substrate is equal to or lower than 600° C. 17. A method for manufacturing a thin film transistor according to claim 15, characterized in that a strain point of the insulating substrate is equal to or lower than 600° C. 18. A method for manufacturing a thin film transistor according to claim 9, characterized in that the gate electrode is led outside the island-shaped semiconductor film. 19. A method for manufacturing a thin film transistor according to claim 10, characterized in that the gate electrode is led outside the island-shaped semiconductor film. 20. A method for manufacturing a thin film transistor according to claim 11, characterized in that the gate electrode is led outside the island-shaped semiconductor film. 21. A method for manufacturing a thin film transistor according to claim 12, characterized in that the gate electrode is led outside the island-shaped semiconductor film. 22. A method for manufacturing a thin film transistor according to claim 13, characterized in that the gate electrode is led outside the island-shaped semiconductor film. 23. An electronic apparatus comprising the thin film transistor according to any one of claim 1 to 4, characterized in that the electronic apparatus is selected from the group consisting of a light emitting device, a digital still camera, a personal computer, a mobile computer, an image reproducing device, a goggle type display, a video camera, and a cellular phone. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor element typified by a field effect transistor to be formed over a substrate having a low strain point and to a method for manufacturing the same, and relates to a semiconductor integrated circuit including the semiconductor element and to a method for manufacturing the same. Specifically, the present invention relates to a thin film transistor in which a gate insulating film is heat-treated at a temperature beyond a strain point of a substrate such as glass and to a method for manufacturing the same. 2. Description of Related Art In recent years, development of a system-on-panel incorporating a logic circuit such as a CPU or a memory as well as a pixel or a driver circuit over a light transmitting insulating substrate such as glass or quartz has been attracting attention. High-speed operation is required for a driver circuit and a logic circuit, and manufacturing a thin film transistor (hereinafter, also referred to as a TFT) having high switching speed is required in order to realize it. It is effective for realizing a TFT having higher switching speed to use a semiconductor film with fewer crystal defects as an active layer; to make a gate insulating film thinner, and to miniaturize a transistor size typified by miniaturization of a gate length. Characteristics required for a gate insulating film can be given as follows: few defects in a thin film; without a fixed charge; a low interface level with a semiconductor film; low leakage current; and the like. However, a gate leakage current tends to increase with a decrease in a film thickness of a gate insulating film. In addition, such a fine gate insulating film that can lower a gate leakage current is required in order to make the gate insulating film thinner. A field effect semiconductor device that can be driven with a low voltage and responds well to a high drive frequency can be obtained by making the gate insulating film thinner. Patent Document 1: Japanese Patent Laid-Open No. H6-188421 SUMMARY OF THE INVENTION In the case of forming a silicon film over a transparent insulating substrate such as glass and manufacturing an integrated circuit by using the silicon film, a manufacturing technique developed in a large-scale integrated circuit using a single crystal silicon substrate cannot be diverted directly. This is because a processing temperature is restricted in terms of heat resistance of glass or the like that is a substrate over which an integrated circuit is formed as well as because of a crystallinity problem of a silicon film (polycrystalline silicon film or the like) for manufacturing an integrated circuit. A gate insulating film which is fine and has good electrical adequacy can be formed by a CVD method, but a film formation temperature is required to be equal to or more than 750° C. A plasma CVD method makes it possible to form a film at a low temperature; however, it is a problem that a film is damaged by a charged particle in plasma and a defect or a pinhole is easily caused. Further, in the case that a film formation temperature is equal to or less than 500° C., hydrogen is included within a film and film stability is decreased. On the contrary, a radio frequency sputtering method can form a thin film without hydrogen contamination. However, a film fine enough to be generally used as a gate insulating film is not obtained by a radio frequency sputtering method in comparison with a CVD method. Miniaturization of an element size is further required to manufacture a TFT having high switching speed that is essential for an element of a logic operation circuit and to obtain higher integration. A high-quality gate insulating film is essential to be formed to achieve the miniaturization. The gate insulating film is preferably heat-treated after the formation in order to form a high-quality gate insulating film. However, a substrate such as glass that expands or shrinks before or after applying a temperature above a strain point has a problem that misalignment occurs in patterning a film formed over the substrate. Therefore, it is difficult to heat-treat a gate insulating film at a temperature above a strain point of the substrate. A typical step of manufacturing a TFT over a glass substrate is described with reference to FIG. 7. FIGS. 7(E) to 7(H) are top views, and FIGS. 7(A) to 7(D) are cross-sectional views along broken lines A-B and broken lines B-C in the respective top views. In FIG. 7, steps of from forming a semiconductor film, element isolation to manufacturing a gate electrode are particularly described. First, a base film 11 and a semiconductor film 12 are formed over an insulating substrate 10 (FIGS. 7(A) and 7(E)). Subsequently, element isolation is performed by processing the semiconductor film 12 into island shapes to form a transistor formation region 13 and a transistor formation region 14 (FIGS. 7(B) and 7(F)). Subsequently, a gate insulating film 15 and a conductive film 16 are formed (FIGS. 7(C) and 7(G)). Lastly, the conductive film 16 is patterned to form a gate electrode 18 (FIGS. 7(D) and 7(H)). Note that a region of the gate insulating film 15 which is not overlapped with the gate electrode 18 is etched by etching in forming the gate electrode 18, and it becomes a gate insulating film 17. As described above, element isolation is performed on the semiconductor film 12 to be island shapes; then, the gate insulating film 15 and the conductive film 16 are formed. Thereafter, the conductive film 16 is patterned with the gate electrode 18 positioned to island-shaped semiconductor films, that is, the transistor formation regions 13 and 14; thus, a transistor is formed. In this method, an upper limit of a process temperature after processing the semiconductor film 12 into island shapes is determined by considering shrinkage of the substrate so that a defect due to misalignment in patterning is not caused. It is an object of the present invention to provide a thin film transistor which enables heat treatment aimed at improving characteristics of a gate insulating film such as lowering of an interface level or reduction in a fixed charge without causing a problem of misalignment in patterning due to expansion or shrinkage of a substrate such as glass and to provide a method for manufacturing the same. Means to Solve the Problem An invention of this specification is a thin film transistor comprising: an island-shaped semiconductor film and an island-shaped gate insulating film patterned by using the same photomask over an insulating substrate; a side wall made of an insulating material formed on a side face of the island-shaped semiconductor film; and a gate electrode formed over the island-shaped gate insulating film, characterized in that the gate electrode overlaps the side face of the island-shaped semiconductor film with the side wall therebetween. An invention of this specification is a thin film transistor comprising: an island-shaped semiconductor film and an island-shaped gate insulating film patterned by using the same photomask over an insulating substrate; a side wall made of an insulating material formed on side faces of the island-shaped semiconductor film and the island-shaped gate insulating film; and a gate electrode formed over the island-shaped gate insulating film, characterized in that the gate electrode overlaps the side face of the island-shaped semiconductor film with the side wall therebetween. An invention of this specification is a thin film transistor comprising: an island-shaped semiconductor film and an island-shaped gate insulating film patterned by using the same photomask over an insulating surface; and a gate electrode formed over the island-shaped gate insulating film, characterized in that a side face of the island-shaped semiconductor film is insulated, and the gate electrode overlaps the insulated side face of the island-shaped semiconductor film. An invention of this specification is a thin film transistor comprising: an island-shaped semiconductor film and an island-shaped gate insulating film patterned by using the same photomask over an insulating substrate; an insulating film patterned to cover side faces of the island-shaped semiconductor film and the island-shaped gate insulating film and only a peripheral portion of a top face of the island-shaped gate insulating film; and a gate electrode formed over the island-shaped gate insulating film, characterized in that the gate electrode overlaps the side face of the island-shaped semiconductor film with the insulating film patterned to cover the side faces of the island-shaped semiconductor film and the island-shaped gate insulating film and only the peripheral portion of the top face of the island-shaped gate insulating film therebetween. An invention of this specification is a method for manufacturing a thin film transistor, characterized by comprising the steps of: forming a semiconductor film over an insulating substrate; forming a first insulating film over the semiconductor film; heat-treating the semiconductor film and the first insulating film; forming an island-shaped semiconductor film and an island-shaped gate insulating film by patterning the semiconductor film and the first insulating film into island shapes with the use of the same photomask after the heat treatment; forming a second insulating film over the island-shaped gate insulating film; forming a side wall covering a side face of the island-shaped semiconductor film and a side face of the island-shaped gate insulating film in a self-aligned manner by anisotropically etching the second insulating film; forming a conductive film over the island-shaped gate insulating film after forming the side wall; and forming a gate electrode by patterning the conductive film. An invention of this specification is a method for manufacturing a thin film transistor, characterized by comprising the steps of: forming a semiconductor film over an insulating substrate; forming an insulating film over the semiconductor film; heat-treating the semiconductor film and the insulating film; forming an island-shaped semiconductor film and an island-shaped gate insulating film by patterning the semiconductor film and the insulating film into island shapes with the use of one resist mask after the heat treatment; insulating a side face of the semiconductor film by adding oxygen or nitrogen to the side face of the island-shaped semiconductor film without removing the resist mask; forming a conductive film over the island-shaped gate insulating film; and forming a gate electrode by patterning the conductive film. An invention of this specification is a method for manufacturing a thin film transistor, characterized by comprising the steps of: forming a semiconductor film over an insulating substrate; forming a first insulating film over the semiconductor film; heat-treating the semiconductor film and the first insulating film; forming an island-shaped semiconductor film and an island-shaped gate insulating film by patterning the semiconductor film and the first insulating film into island shapes with the use of one photomask after the heat treatment; forming a second insulating film over the island-shaped gate insulating film; patterning the second insulating film to cover edge portions of the island-shaped semiconductor film and the island-shaped gate insulating film and only a peripheral portion of a top face of the island-shaped gate insulating film; forming a conductive film over the island-shaped gate insulating film; and forming a gate electrode by patterning the conductive film. An invention of this specification is a method for manufacturing a thin film transistor, characterized by comprising the steps of: forming a semiconductor film over an insulating substrate; forming a first insulating film on the semiconductor film; forming a first conductive film over the first insulating film; heat-treating the semiconductor film, the first insulating film, and the first conductive film; forming an island-shaped semiconductor film, an island-shaped gate insulating film, and a first island-shaped conductive film by patterning the semiconductor film, the first insulating film, and the first conductive film into island shapes with the use of the same photomask after the heat treatment; forming a second insulating film over the first island-shaped conductive film; forming a side wall covering a side face of the island-shaped semiconductor film, a side face of the island-shaped gate insulating film, and a side face of the first island-shaped conductive film in a self-aligned manner by anisotropically etching the second insulating film; forming a second conductive film over the first island-shaped conductive film after forming the side wall; and forming a gate electrode by patterning the first island-shaped conductive film and the second conductive film. An invention of this specification is a method for manufacturing a thin film transistor, characterized by comprising the steps of: forming a semiconductor film over an insulating substrate; forming an insulating film over the semiconductor film; forming a first conductive film over the insulating film; heat-treating the semiconductor film, the insulating film, and the first conductive film; forming an island-shaped semiconductor film, an island-shaped gate insulating film, and a first island-shaped conductive film by patterning the semiconductor film, the insulating film, and the first conductive film into island shapes with the use of the same resist mask after the heat treatment; insulating a side face of the semiconductor film by adding oxygen or nitrogen to the side face of the island-shaped semiconductor film without removing the resist mask; forming a second conductive film over the first island-shaped conductive film; and forming a gate electrode by patterning the first island-shaped conductive film and the second conductive film. An invention of this specification is a method for manufacturing a thin film transistor, characterized by comprising the steps of: forming a semiconductor film over an insulating substrate; forming a first insulating film over the semiconductor film; forming a first conductive film over the insulating film; heat-treating the semiconductor film, the first insulating film, and the first conductive film; forming an island-shaped semiconductor film, an island-shaped gate insulating film, and a first island-shaped conductive film by patterning the semiconductor film, the first insulating film, and the first conductive film into island shapes with the use of the same photomask after the heat treatment; forming a second insulating film over the first island-shaped conductive film; patterning the second insulating film to cover edge portions of the island-shaped semiconductor film, the island-shaped gate insulating film, and the first island-shaped conductive film and only a peripheral portion of a top face of the first island-shaped conductive film; forming a second conductive film over the island-shaped gate insulating film; and forming a gate electrode by patterning the first conductive film and the second conductive film. A method for manufacturing a thin film transistor according to the invention of this specification further is characterized by comprising the steps of: heat-treating in a state where at least a gate insulating film is formed over a semiconductor film on which element isolation is not performed; isolating the gate insulating film and the semiconductor film into an element structure by using one photomask after the heat treatment; forming an insulating film covering a side face of an exposed semiconductor film; and forming a gate electrode over the gate insulating film. Expansion or shrinkage of a substrate such as glass during the heat treatment can be prevented from affecting misalignment in patterning since the gate insulating film and the semiconductor film are simultaneously patterned and processed into element shapes after the heat treatment. The side face of the semiconductor film is exposed in a condition that the gate insulating film and the semiconductor film are simultaneously patterned and processed into element shapes. Then, one feature is that an insulating film covering the side face of the semiconductor film is formed before forming an electrode such as a gate electrode or a wiring over the gate insulating film. Thus, a short circuit is prevented between the semiconductor film that is processed into an element structure and an electrode or a wiring to be formed over the gate insulating film. In the invention of this specification, a substrate having a lower strain point than a heat treatment temperature of from 600° C. to 800° C. to be applied to a gate insulating film is effectively used as an insulating substrate over which a thin film transistor is formed, regardless of its type. Further, a laminated film of a semiconductor film and a gate insulating film on which element isolation is not performed is simultaneously heat-treated in the invention of this specification. Furnace or RTA (Rapid Thermal Anneal) may be used for the heat treatment. Either gas heating or lamp heating can be used in RTA treatment. Preferably, lamp heating treatment may be performed with up to a conductive film for forming at least one part of a gate electrode formed over the laminated film. In the case of using a halogen lamp having a peak of an emitted spectrum in an infrared region, the conductive film effectively absorbs emitted light. Not only can the gate insulating film be effectively heated, but also an interface between the gate insulating film and the conductive film can be heat-treated. Consequently, characteristics such as reduction in a leakage current resulting from the interface between the gate electrode and the gate insulating film can be improved. A side face of the semiconductor film is exposed in the case of simultaneously performing element isolation on the laminated film including the semiconductor film and the gate insulating film. Therefore, the side face of the semiconductor film is short-circuited with the gate electrode in the case of successively forming a conductive film for forming the gate electrode. Particularly, the side face of the semiconductor film and a portion for leading the gate electrode outside the semiconductor film on which element isolation is performed are short-circuited. Then, an insulating film covering the side face of the semiconductor film is required. The insulating film covering the side face of the semiconductor film can be formed by forming an insulating film covering an entire surface of the substrate over patterned semiconductor film and gate insulating film, anisotropically etching the insulating film, and processing into a side wall shape in a self-aligned manner. In addition, a method for insulating the side face of the semiconductor film at a low temperature or a method for patterning the insulating film to cover side faces of the semiconductor film and the gate insulating film and only a peripheral portion of a top face of the gate insulating film is given as another method for forming the insulating film covering the side face of the semiconductor film. The insulating film covering the side face of the semiconductor film can be formed to have higher precision since there is no misalignment in the case of forming in a self-aligned manner. Therefore, in the case of intending integration, it is preferable to manufacture the insulating film by a method for forming into a side wall shape or a method for insulating the side face of the semiconductor film at a low temperature. In this way, the insulating film is formed only on a desired side face of a semiconductor film. According to the present invention having the above structures, a gate insulating film can be heat-treated without a problem of an alignment defect in patterning even at a temperature of 700° C. that conventionally causes a problem of misalignment in patterning due to shrinkage of a substrate such as glass. In the present invention, a gate insulating film can be heat-treated at a temperature of 700° C. above a strain point of a substrate such as glass. Therefore, an interface level is lowered; a fixed charge is reduced; a gate leakage current is lowered; field-effect mobility, subthreshold coefficient, and the like become favorable; a change of transistor characteristics over time during continuous operation can be reduced; a yield is improved; and variation in the characteristics is reduced, in a thin film transistor. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A-1H are diagrams showing a step of manufacturing a thin film transistor of the present invention. FIGS. 2A-2J are diagrams showing a step of manufacturing a thin film transistor of the present invention. FIGS. 3A-D3 are diagrams showing a step of manufacturing a thin film transistor of the present invention. FIGS. 4A-4C are diagrams showing a pixel structure of a display panel according to the present invention. FIGS. 5A-5D are diagrams showing a structure of a display panel according to the present invention. FIGS. 6A-6H are diagrams showing structures of electronic apparatuses according to the present invention. FIGS. 7A-7H are diagrams showing a step of manufacturing a thin film transistor in which element isolation is performed on a semiconductor film before forming a gate insulating film. EMBODIMENT OF THE INVENTION Embodiment Mode 1 A glass substrate made of a material such as barium borosilicate glass, alumino borosilicate glass, or aluminosilicate glass, or the like can be given as a substrate which can be applied in this embodiment mode. Typically, a 1737 glass substrate (strain point: 667° C.) manufactured by Corning, Inc., AN100 (strain point: 670° C.) manufactured by Asahi Glass Co., Ltd., or the like can be applied, but there is no particular limitation on other similar substrates. A first inorganic insulating layer 21 made of an insulating film such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiOxNy) is formed over a glass substrate 20, as shown in FIGS. 1(A) and 1(E), using the above substrate. A typical example of the first inorganic insulating layer 21 has a two-layer structure, which is a structure where a first silicon oxynitride film formed to be 50 nm in thickness by a plasma CVD method using SiH4, NH3, and N2O as a reactive gas and a second silicon oxynitride film formed to be 100 nm in thickness by a plasma CVD method using SiH4 and N2O as a reactive gas are laminated. A crystalline semiconductor film 22 serving as an active layer of a TFT is obtained by crystallizing an amorphous semiconductor film formed over the first inorganic insulating layer 21. A crystalline silicon film or the like can be used for the crystalline semiconductor film 22. Thickness of the amorphous semiconductor film is selected in the range where thickness of the crystalline semiconductor film 22 obtained by crystallizing the amorphous semiconductor film is to be from 20 nm to 60 nm. An upper limit of the film thickness of the crystalline semiconductor film 22 serving as an active layer of a TFT is a maximum value for operating as a fully depleted type in a channel region of a TFT. A lower limit of the film thickness is a limitation on a process, and is set as a minimum value required in selectively processing only the crystalline semiconductor film 22 during an etching step of the crystalline semiconductor film 22. A gate insulating film 23 is formed over the crystalline semiconductor film 22. A silicon oxide film formed by a reactive sputtering method using Ar and 02 and utilizing a Si target, a silicon oxynitride film formed by a CVD method using SiH4, NH3, and N2O as a reactive gas, or the like can be used for the gate insulating film 23. The gate insulating film 23 is not limited to a silicon compound, and high dielectric constant metal oxide that has a higher dielectric constant than that of silicon oxide and by which an effect of making the gate insulating film thinner is effectively obtained may be used. Effective film thickness can be expressed as a product t·k1/k2 of actual film thickness t and ratio k1/k2 of a relative dielectric constant k1 of a film material to be a benchmark such as silicon oxide to a relative dielectric constant k2 of an actual film material. Note that a film thickness of the gate insulating film 23 is set by a scaling law and a process margin, and the thickness of the gate insulating film 23 is set to be from 20 nm to 80 nm in order to manufacture a TFT with a gate length of from 0.35 μm to 2.5 μm here. Subsequently, a first conductive film 24 is formed over the gate insulating film 23. A tantalum nitride film is formed by reactive sputtering using Ar and N2 gas and utilizing a Ta target to have a film thickness of from 10 nm to 50 nm for the first conductive film 24. Another conductive film as well as a tantalum compound may be used for the first conductive film 24. However, the first conductive film 24 is preferably a material that absorbs light within a wavelength of approximately 1 μm and a material that can have an enough selective ratio in etching with a second conductive film 34 to be formed later. Subsequently, the crystalline semiconductor film 22, the gate insulating film 23, and the first conductive film 24 are heat-treated, as shown in FIGS. 1(B) and 1(F). RTA treatment that is capable of heating and cooling instantaneously is employed as heat treatment. A temperature rises up to a temperature of from 600° C. to 800° C. in 10 seconds to 120 seconds, and heat treatment is performed at a temperature of from 600 □C to 800° C. for 30 seconds to 180 seconds in RTA treatment. Note that there are a gas heating method using a heated gas and a lamp heating method by emission of a lamp as the RTA treatment. The glass substrate 20 itself is heated by a gas in the case of the gas heating method, and the gate insulating film 23 can be heat-treated. However, temperature rising efficiency is generally remarkably inefficient in the lamp heating method. This is because the glass substrate 20 itself is hard to be heated since a typical halogen lamp has a peak of an emitted spectrum at approximately 1 μm and the glass substrate 20 does not sufficiently absorb light within such a wavelength region by itself. In this embodiment mode, heat conduction to the gate insulating film 23 occurs by using a tantalum nitride film as an absorber layer since the tantalum nitride film that is the first conductive film 24 absorbs light within a wavelength of approximately 1 μm. Consequently, the gate insulating film 23 can be efficiently heat-treated. Note that the heat treatment is performed at a temperature above the strain point of glass, and shrinkage of the glass substrate 20 is caused. However, a patterning defect due to the shrinkage is not caused in a later step since the crystalline semiconductor film 22 is not processed into an element shape yet at the time of the heat treatment. Subsequently, the crystalline semiconductor film 22, the gate insulating film 23, and the first conductive film 24 are collectively etched into island shapes by using the same photomask, as shown in FIGS. 1(C) and 1(G). For example, an ICP (Inductively Coupled Plasma) etching method can be applied as an etching method. A mixed gas of CF4 and C12 can be used as an etching gas in etching the first conductive film 24 made of a tantalum nitride film. A CHF3 gas can be used for etching the gate insulating film 23 made of a silicon oxide film, and a mixed gas of CF4 and O2 can be used in etching the crystalline semiconductor film 22 made of a crystalline silicon film. Thus, a crystalline semiconductor film 25 and a crystalline semiconductor film 28 which are processed into island shapes, a gate insulating film 26 and a gate insulating film 29 which are processed into island shapes, and a first conductive film 27 and a first conductive film 30 which are processed into island shapes are formed. Subsequently, an insulating film 31 covering an entire surface of the glass substrate 20 is formed to cover exposed side faces of the crystalline semiconductor film 25 and the crystalline semiconductor film 28 as shown in FIGS. 1(D) and 1(H). A silicon oxide film formed by a low pressure CVD method which isotropically grows to have a film thickness of from 500 nm to 1.5 μm is used as the insulating film 31. Note that the insulating film 31 is only necessary to be an insulating film, and a silicon nitride film or a silicon oxynitride film can be used without being limited to the silicon oxide film. Subsequently, a side wall 32 and a side wall 33 covering side faces of the crystalline semiconductor film 25 and the crystalline semiconductor film 28 and side faces of the gate insulating film 26 and the gate insulating film 29 can be formed as shown in FIGS. 2(A) and 2(F) by applying a predetermined bias voltage to a glass substrate 20 side and anisotropically etching the insulating film 31 made of a silicon oxide film. Effective thickness of the side wall 32 and the side wall 33 in a portion covering the side faces of the crystalline semiconductor film 25 and the crystalline semiconductor film 28 in a direction perpendicular to the side faces is set equal to or thicker than effective thickness of the gate insulating film 26 and the gate insulating film 29. For instance, when all the gate insulating film 26, the gate insulating film 29, the side wall 32, and the side wall 33 are made of silicon oxide films, thickness of the side wall 32 and the side wall 33 in a portion covering the side faces of the crystalline semiconductor film 25 and the crystalline semiconductor film 28 in a direction perpendicular to the side faces is set at equal to or more than from 20 nm to 80 nm that is thickness of the gate insulating film 26 and the gate insulating film 29. In this way, a short circuit and a current leakage can be suppressed between a portion for leading a gate electrode outside the semiconductor film on which element isolation is performed and the side faces of the crystalline semiconductor film 25 and the crystalline semiconductor film 28. Then, a second conductive film 34 shown in FIGS. 2(B) and 2(G) is formed. A tungsten film having a film thickness of from 300 nm to 500 nm is used as the second conductive film 34 in this embodiment mode. The second conductive film 34 is not limited to a tungsten film, and is only necessary to be a conductive film. However, a material having an enough selective ratio in etching with the first conductive film 24 is preferably used for the second conductive film 34. A first conductive layer 37 and a first conductive layer 40 made of tantalum nitride and a second conductive layer 38 made of tungsten, which are processed into a shape of a gate electrode, are obtained by etching the first conductive film 24 and the second conductive film 34, as shown in FIGS. 2(C) and 2(H). Here, a structure in which the first conductive layer 37, the first conductive layer 40, and the second conductive layer 38 have different tilt angles in edge portions is manufactured. The first conductive layer 37, the first conductive layer 40, and the second conductive layer 38 having different tilt angles in the edge portions are formed by performing two-stage etching treatment on the first conductive film 24 and the second conductive film 34. In the first stage of etching, both tungsten and tantalum nitride are simultaneously etched by applying a predetermined voltage to the glass substrate 20 with the use of a mixed gas of CF4, Cl2, and O2 as an etching gas, and a layer made of tungsten and a layer made of tantalum nitride having the same tilt angles in edge portions are manufactured. Subsequently, in the second stage of etching, only the layer made of tungsten is anisotropically etched by applying a predetermined bias voltage to the glass substrate 20 under the first stage etching condition in which the etching gas is replaced with SF6, Cl2, and O2. In this way, the first conductive layer 37, the first conductive layer 40, and the second conductive layer 38 having different tilt angles in the edge portions are formed. Note that the gate insulating film 26, the gate insulating film 29, the side wall 32, and the side wall 33 are also etched to be a gate insulating film 36, a gate insulating film 39, a side wall 35a, and a side wall 35b respectively in a process of etching the first conductive layer 37, the first conductive layer 40, and the second conductive layer 38. Then, a desired quantity of impurities is doped. 41 and 44 in FIGS. 2(D) and 2(I) become a source or a drain doped with an n-type or a p-type impurity in high concentration respectively; 42 and 45 become doping regions doped with an n-type impurity in lower concentration than those in the source or drain 41 and the source or drain 44 (Gate Overlapped Lightly Doped Drain) since they are doped through the edge portions of the first conductive layer 37 and the first conductive layer 40 that are parts of the gate electrodes; and 43 and 46 become channel regions. Thereafter, as shown in FIGS. 2(E) and 2(J), a silicon oxynitride film containing hydrogen is formed as an insulating film 51 to have a film thickness of 100 nm by a plasma CVD method, and the crystalline semiconductor film 25, the crystalline semiconductor film 28, the gate insulating film 36, and the gate insulating film 39 are hydrogenated by heat-treating at 410° C. Further, a silicon oxide film is formed as an interlayer insulating film 52 to have a film thickness of from 400 nm to 600 nm by a CVD method. Note that phosphorous glass (PSG), boron phosphorous glass (BSG), or phosphorous boron glass (PBSG) can be applied to the interlayer insulating film 52. A porous film or a low dielectric constant film such as acrylic of an organic resin system or Teflon (registered trademark) can be used as the interlayer insulating film 52 as well. Then, a silicon nitride film is formed as a barrier film 53 to have a film thickness of 100 nm by a sputtering method. In the next place, a wiring 47, a wiring 48, a wiring 49, and a wiring 50 are formed after forming contact portions to reach the source or drain 41 and the source or drain 44 by etching the barrier film 53, the interlayer insulating film 52, the insulating film 51, the gate insulating film 36, and the gate insulating film 39. A laminate structure of a titanium film with a thickness of 60 nm, a titanium nitride film with a thickness of 40 nm, an aluminum film with a thickness of 300 nm, and a titanium film with a thickness of 100 nm is used for the wirings 47 to 50. However, a structure of the wirings 47 to 50 is not limited to the above structure, and copper can be used in place of aluminum. A film in contact with the aluminum film is not limited to titanium nitride, and tantalum nitride, tungsten nitride, or the like can be used in the wirings 47 to 50. Embodiment Mode 2 Ozone is used at a temperature of 500° C. to oxidize the crystalline semiconductor film 25, the crystalline semiconductor film 28, the gate insulating film 26, the gate insulating film 29, the first island conductive film 27, and the first island conductive film 30 which are processed into island shapes as shown in FIGS. 1(C) and 1(G) in Embodiment Mode 1. Thus, oxide films are formed on exposed side faces of the crystalline semiconductor film 25 and the crystalline semiconductor film 28, and effective thickness of the oxide films is set equal to or thicker than effective thickness of the gate insulating film 26 and the gate insulating film 29 as shown in FIGS. 3(A) and 3(C), thereby preventing a short circuit between a gate electrode to be formed later and the side faces of the crystalline semiconductor film 25 and the crystalline semiconductor film 28. Note that an oxide film, a nitride film, an oxynitride film, or the like can be used as an insulating film to be formed on the side faces of the crystalline semiconductor film 25 and the crystalline semiconductor film 28. Plasma oxidization as well as a method using an ozone gas can be performed by using plasma including oxygen as an oxidation method. In addition, washing by using ozone water may be performed as an oxidation method, and in this case, oxidation can be performed efficiently by irradiating a surface of the glass substrate 20 with ultraviolet light. Plasma nitriding can be performed by using plasma including a nitrogen gas as a nitriding method. Further, only the side faces of the crystalline semiconductor film 25 and the crystalline semiconductor film 28 can be selectively made insulative by doping oxygen or nitrogen with a resist mask used in patterning the island-shaped crystalline semiconductor film 25, the island-shaped crystalline semiconductor film 28, the gate insulating film 26, the gate insulating film 29, the first conductive film 27, and the first conductive film 30 remained. Embodiment Mode 3 An insulating film is formed over an entire surface of the glass substrate 20 to cover the crystalline semiconductor film 25, the crystalline semiconductor film 28, the gate insulating film 26, and the gate insulating film 29 after forming the crystalline semiconductor film 25, the crystalline semiconductor film 28, the gate insulating film 26, the gate insulating film 29, the first conductive film 27, and the first conductive film 30 which are processed into island shapes as shown in FIGS. 1(C) and 1(G) in Embodiment Mode 1. A silicon oxide film formed to have a thickness of from 50 nm to 100 nm by a CVD method is used as the insulating film. The insulating film is not limited to the silicon oxide film formed by a CVD method, and a silicon nitride film, a silicon oxynitride film, or the like can be used. A film formation method is also not limited to a CVD method, and a sputtering method, or the like can be applied. Then, the insulating film is patterned to form insulating layers 54 to 57 as shown in FIGS. 3(B) and 3(D). The insulating layers 54 to 57 are shaped to cover side faces of the island-shaped crystalline semiconductor film 25 and the island-shaped crystalline semiconductor film 28 in a region overlapped with at least a gate electrode to be formed later, and effective thickness of the insulating layers 54 to 57 is set equal to or thicker than effective thickness of the gate insulating film 26 and the gate insulating film 29, thereby preventing a short circuit between the crystalline semiconductor film 25 and the crystalline semiconductor film 28 and the gate electrode to be formed later. Embodiment Embodiment 1 A cross-sectional structure in the case of manufacturing a display device by using a typical thin film transistor manufactured according to Embodiment Modes 1 to 3 is described. A TFT disposed in a driver circuit portion and a pixel portion is formed over a substrate 500 having an insulating surface according to manufacturing steps described in the above embodiment modes. Thereafter (FIG. 4(A)), a first electrode 501 made of a transparent conductive film is formed to electrically connect with a wiring 507 of a driving TFT 513. The transparent conductive film is preferably made of a material having a high work function, and the following can be given as an example thereof: a compound of indium oxide and tin oxide (ITO); a compound of indium oxide and zinc oxide; zinc oxide; tin oxide; indium oxide; titanium nitride; or the like. In this embodiment, an ITO film with a thickness of 0.1 μm was formed by a sputtering method as the first electrode 501. In this embodiment, a method for forming the transparent conductive film to electrically connect with the wiring 507 after forming the wiring 507 was described, but the transparent conductive film may be formed by another method. For example, the wiring 507 of the TFT may be formed to electrically connect with the first electrode after forming the transparent conductive film and forming the first electrode by patterning the transparent conductive film. In addition, after forming the wiring 507 of the TFT, an insulating film is formed over the wiring 507, and thereafter, a contact hole is formed in the insulating film to reach the wiring 507. Then, the transparent conductive film may be formed to electrically connect with the wiring 507 through the contact hole. Subsequently, an insulating film 504 is formed to cover an end face of the first electrode 501. There is no particular limitation on a material for forming the insulating film 504, and the insulating film 504 can be made of an inorganic or organic material. The insulating film 504 is preferably made of a photosensitive organic material since a shape of the opening portion provided for the insulating film 504 becomes such a shape that disconnection in a light emitting layer to be evaporated over the insulating film 504 is hardly caused. Namely, the shape of the opening portion provided for the insulating film 504 can be made into such a gently curved shape that a slope of a surface on which the light emitting layer is formed continuously changes, thereby improving coverage of the light emitting layer and preventing disconnection in the light emitting layer. Consequently, a short circuit between an anode and a cathode due to breaking of a wiring of a light emitting element is reduced. In addition, the light emitting layer can be prevented from becoming thin partly and an electric field can be prevented from concentrating locally in the light emitting layer. A photosensitive polyimide resin, photosensitive acrylic, or the like can be used as the photosensitive organic material for forming the insulating film 504. For example, in the case of using a negative photosensitive resin as a material of the insulating film 504, a shape of an upper end portion of the insulating film 504 in contact with a top face of the first electrode 501 can be formed to be a curved shape that has a center of curvature below a tangent to a top face of the insulating film 504 and the upper end portion of the insulating film 504 and is determined by a first curvature radius. A shape of a lower end portion of the insulating film 504 can be formed to be a curved shape that has a center of curvature above a tangent to the first electrode 501 and the lower end portion of the insulating film 504 and is determined by a second curvature radius. The first and the second curvature radii are preferable from 0.2 μm to 3 μm, and an angle of a side wall of the opening portion to the first electrode 501 is preferably equal to or more than 35°. Subsequently, dust or the like is removed by wiping with a porous body of a PVA (polyvinyl alcohol) system. In this embodiment, fine powder (dust) generated in etching the first electrode 501 made of an ITO or the insulating film 504 was removed by wiping with the porous body of PVA. Subsequently, a light emitting layer 502 is formed to be in contact with the first electrode 501. The light emitting layer 502 is formed by an evaporation method or an application method (a spin coating method, an ink-jetting method, or the like). In this embodiment, a method for evaporating with an evaporation source moving was employed. In this method, an organic compound which is a material of the light emitting layer 502 and is put in the evaporation source is vaporized in advance by resistance heating, and a shutter is provided to prevent the vaporized organic compound from being scattered in a direction of the glass substrate 20 from the evaporation source. In evaporating, the vaporized organic compound was scattered upwardly by opening the shutter and was evaporated over the glass substrate 20 through an opening portion provided for a metal mask, thereby forming the light emitting layer 502. Note that PEDOT may be entirely applied and may be baked as treatment before evaporation of the light emitting layer 502. It is preferable to wash PEDOT after PEDOT is once applied and to apply PEDOT again since PEDOT has poor wettability with ITO that is the first electrode 501. In this way, after applying PEDOT, a heat treatment is performed at normal pressure to vaporize moisture, and then, a heat treatment is performed under reduced pressure. One of or a plurality of layers to be provided between the first electrode and a second electrode forming a light emitting element is generically referred to as the light emitting layer (layer including a light emitting material) 502. The light emitting layer 502 can be formed by using a low molecular weight organic compound material, a high molecular weight organic compound material, or a mixture thereof appropriately. Further, a mixed layer in which an electron transporting material and a hole transporting material are appropriately mixed, or a mixed bonding in which a mixed region is formed at a bond interface of each material may be formed. In addition to an organic material, an inorganic light emitting material may be used. Further, a laminate structure of the light emitting layer 502 is not particularly limited, and a structure in which layers made of a low molecular weight material are laminated or a structure in which a layer made of a high molecular weight material and a layer made of a low molecular weight material are laminated may be adopted. Subsequently, a second electrode 503 is formed over the light emitting layer 502. The second electrode 503 is made of a laminated film of a thin film containing metal having a small work function (Li, Mg, or Cs) and a transparent conductive film laminated over the thin film containing Li, Mg, or the like. The film thickness is properly set to function as a cathode, but here, it is set at approximately from 0.01 μm to 1 μm in thickness by a known method (an electron beam evaporation method or the like). However, in the case of employing an electron beam evaporation method, radiation is generated when an acceleration voltage is too high, and thus, a TFT is damaged. However, when an acceleration voltage is too low, film formation speed is slowed down and productivity decreases. Therefore, the second electrode 503 is formed so as not to be excessively thicker than such a film thickness that the second electrode functions as a cathode. When the second electrode 503 is thin, the productivity is not affected significantly even if the film formation speed is slow. However, a problem of increase in resistance arises when the cathode is thin. The problem can be solved by forming Al or the like which is a low-resistance metal over the cathode by resistance heating evaporation or a sputtering method to be a laminated structure. In this embodiment, Al—Li was formed to be 0.1 μm in thickness as the second electrode 503 by an electron beam evaporation method. Subsequently, a protective film 505 is formed over the insulating film 504 and the second electrode 503. A film that is hardly penetrated, compared to other insulating films, by a substance such as moisture or oxygen to be a cause of accelerating deterioration of a light emitting element 506 is used as the protective film 505. Typically, a DLC film, a carbon nitride film, a silicon nitride film formed by an RF sputtering method, or the like is preferably used. In addition, film thickness thereof is preferably approximately from 10 nm to 200 nm. In this embodiment, a silicon nitride film was formed to have a thickness of 100 nm by a sputtering method. A laminate of the first electrode 501, the light emitting layer 502, and the second electrode 503, which is formed in the above-described steps, corresponds to the light-emitting element 506. The first electrode 501 corresponds to an anode, and the second electrode 503 corresponds to a cathode. In the present invention, there are singlet excitation and triplet excitation as an excitation state of the light emitting element 506, and luminescence can be generated through either excitation state. FIG. 4(B) shows a top view of one pixel in a display device using a light emitting element. FIG. 4(B) shows a state that up to a pixel electrode 501 is formed. In the top view of FIG. 4(B), a cross sectional view equivalent to A-B-C corresponds to FIG. 5(A). Further, FIG. 4(C) shows a circuit diagram of one pixel equivalent to FIG. 4(B). In FIGS. 4(B) and 4(C), reference numeral 508 denotes a source line; 509, a gate line; 510, a power source line; 511, a capacitor element; 501, the first electrode (pixel electrode); 512, a switching TFT; and 513, the driving TFT. In this embodiment, a case where so-called bottom emission in which light emitted from the light emitting element 506 was extracted from a side of the substrate 500 was performed was described. However, so-called top emission in which light is extracted from a direction opposite to the substrate 500 may be performed, instead. In that case, the first electrode 501 is formed to correspond to the cathode, and the second electrode 503 is formed to correspond to the anode. Further, the second electrode 503 is preferably made of a transparent material. In addition, the driving TFT 513 is preferably made of an n-channel TFT. Note that a conductivity type of the driving TFT 513 may be appropriately changed, but the capacitor element 511 is arranged to hold voltage between the gate and the source. Note that the case of a light emitting device using the thin film transistor and the light emitting element of the present invention is described in this embodiment; however, the present invention can be applied to another display device such as a liquid crystal display device. This embodiment can be freely combined with the above-described embodiment modes. Embodiment 2 An embodiment of the present invention is described with reference to FIG. 5. FIG. 5(A) is a top view of a display panel formed by sealing a substrate over which a TFT is formed with a sealing material. FIG. 5(B) is a cross-sectional view along a line B-B′ in FIG. 5(A). FIGS. 5(C) and 5(D) are cross-sectional views along a line A-A′ in FIG. 5(A). Note that FIG. 5(C) is a cross-sectional view of a display panel performing bottom emission in which light is emitted in a direction of the substrate over which a TFT is formed. FIG. 5(D) is a cross-sectional view of a display panel performing top emission in which light is emitted in a direction opposite to the substrate over which a TFT is formed. In FIGS. 5(A) to 5(D), a pixel portion (display portion) 602, a signal line driver circuit 603 which is disposed to surround the pixel portion 602, scanning line driver circuit 604a, and scanning line driver circuit 604b are all disposed over a substrate 601, and a seal material 606 is provided to surround all of them. The structure described in the above Embodiment 1, or the like can be applied to a structure of the pixel portion 602. A glass material, a metal material, a ceramic material, or a plastic material is used as the seal material 606. The seal material 606 may be provided to partially overlap the signal line driver circuit 603, the scanning line driver circuit 604a, and the scanning line driver circuit 604b. In a display panel shown in FIG. 5(C), a sealing material 607 is provided by using the seal material 606 as an adhesive layer, so that a closed space 608 is formed with the substrate 601, the seal material 606, and the sealing material 607. A hygroscopic agent 609 is provided in advance for a depression of the sealing material 607, so that it has a function of absorbing moisture, oxygen, and the like to keep an atmosphere clean in an inner portion of the closed space 608, thereby suppressing deterioration of the light emitting element. The depression is covered with a cover material 610 with a fine mesh shape. The cover material 610 allows air and moisture to pass therethrough but not the hygroscopic agent 609. Note that the closed space 608 may be filled with a noble gas such as nitrogen or argon, or can be filled with a resin or a liquid as long as it is inert. In a display panel in FIG. 5(D), a transparent opposing substrate 621 is provided by using the seal material 606 as an adhesive layer, so that a closed space 622 is formed with the substrate 601, the opposing substrate 621, and the seal material 606. The opposing substrate 621 is provided with a color filter 620 and a protective film 623 for protecting the color filter. Light emitted from the light emitting element disposed in the pixel portion 602 is exteriorly emitted through the color filter 620, and the display panel performs multicolor display. The closed space 622 is filled with an inert resin, an inert liquid, or the like. In the case of performing multi color display, the light emitting layer may be set to emit each color of RGB, or a pixel provided with a light emitting layer that emits white light may be arranged in order that the color filter or a color conversion layer is used. An input terminal portion 611 for transmitting a signal to the signal line driver circuit 603, the scanning line driver circuit 604a, and the scanning line driver circuit 604b is provided over the substrate 601. A data signal such as a video signal is transmitted to the input terminal portion 611 through an FPC 612. A cross section of the input terminal portion 611 is as shown in FIG. 5(B), and an input wiring 613 made of a wiring which is formed together with the scanning line or the signal line is electrically connected to a wiring 615 provided on a side of the FPC 612 by using a resin 617 in which a conductive material 616 is dispersed. Note that a spherical high molecular weight compound plated with gold or silver may be used as the conductive material 616. In this embodiment, an example of applying the present invention to the light-emitting panel using the light emitting element is described; however, the present invention may be applied to a liquid crystal panel using a liquid crystal display element. This embodiment can be freely combined with other above-described embodiment modes and embodiments. Embodiment 3 The following can be given as examples of electronic apparatuses to which the present invention is applied: a video camera; a digital camera; a goggle type display; a navigation system; an audio reproducing device (car audio, or the like); a laptop computer; a game machine; a personal digital assistant (a mobile computer, a cellular phone, or the like); an image reproducing device including a recording medium; and the like. Practical examples of these electronic apparatuses are shown in FIG. 6. FIG. 6(A) shows a light emitting device, which includes a chassis 2001, a supporting section 2002, a display portion 2003, speaker portions 2004, a video input terminal 2005, and the like. The present invention can be applied to the display portion 2003. The light emitting device is self-luminous and does not need a backlight, so that the display portion can be made thinner than that of a liquid crystal display. Note that the light emitting device includes all display devices for displaying information, including ones for personal computers, for TV broadcasting reception, and for advertisement. FIG. 6(B) shows a digital still camera, which includes a main body 2101, a display portion 2102, an image receiving portion 2103, operation keys 2104, an external connection port 2105, a shutter 2106, and the like. The present invention can be applied to the display portion 2102. FIG. 6(C) shows a laptop personal computer, which includes a main body 2201, a chassis 2202, a display portion 2203, a keyboard 2204, an external connection port 2205, a pointing mouse 2206, and the like. The present invention can be applied to the display portion 2203. FIG. 6(D) shows a mobile computer, which includes a main body 2301, a display portion 2302, an electric switch 2303, operation keys 2304, an infrared port 2305, and the like. The present invention can be applied to the display portion 2302. FIG. 6(E) shows a portable image reproducing device including a recording medium (specifically, a DVD reproducing device), which includes a main body 2401, a chassis 2402, a display portion A 2403, a display portion B 2404, a recording medium reading portion 2405, operation keys 2406, speaker portions 2407, and the like. The display portion A 2403 mainly displays image information whereas the display portion B 2404 mainly displays text information. The present invention can be applied to the display portion A 2403 and the display portion B 2404. FIG. 6(F) shows a goggle type display (head mounted display), which includes a main body 2501, display portions 2502, and arm portions 2503. The present invention can be applied to the display portions 2502. FIG. 6(G) shows a video camera, which includes a main body 2601, a display portion 2602, a chassis 2603, an external connection port 2604, a remote control receiving portion 2605, an image receiving portion 2606, a battery 2607, an audio input portion 2608, operation keys 2609, an eye piece portion 2610, and the like. The present invention can be applied to the display portion 2602. FIG. 6(H) shows a cellular phone, which includes a main body 2701, a chassis 2702, a display portion 2703, an audio input portion 2704, an audio output portion 2705, operation keys 2706, an external connection port 2707, an antenna 2708, and the like. The present invention can be applied to the display portion 2703. Note that if the display portion 2703 displays white letters on black background, the cellular phone consumes less power. As described above, the applicable range of the present invention is so wide that the invention can be applied to electronic devices of various fields. In addition, the electronic devices of this embodiment can be freely combined with the above embodiment modes and embodiments. Advantageous Effect of the Invention According to the present invention, a gate insulating film can be heat-treated without an alignment defect in patterning even at a temperature of 700° C. that conventionally causes a problem of alignment in patterning due to shrinkage of a substrate such as glass. By heat-treating a gate insulating film at a temperature of 700° C. above a strain point of glass, an interface level is lowered; a fixed charge is reduced; a gate leakage current is lowered; field-effect mobility, subthreshold coefficient, and the like become favorable; a change of transistor characteristics over time during continuous operation is reduced; a yield is improved; and variation in the characteristics is reduced, in a thin film transistor. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a semiconductor element typified by a field effect transistor to be formed over a substrate having a low strain point and to a method for manufacturing the same, and relates to a semiconductor integrated circuit including the semiconductor element and to a method for manufacturing the same. Specifically, the present invention relates to a thin film transistor in which a gate insulating film is heat-treated at a temperature beyond a strain point of a substrate such as glass and to a method for manufacturing the same. 2. Description of Related Art In recent years, development of a system-on-panel incorporating a logic circuit such as a CPU or a memory as well as a pixel or a driver circuit over a light transmitting insulating substrate such as glass or quartz has been attracting attention. High-speed operation is required for a driver circuit and a logic circuit, and manufacturing a thin film transistor (hereinafter, also referred to as a TFT) having high switching speed is required in order to realize it. It is effective for realizing a TFT having higher switching speed to use a semiconductor film with fewer crystal defects as an active layer; to make a gate insulating film thinner, and to miniaturize a transistor size typified by miniaturization of a gate length. Characteristics required for a gate insulating film can be given as follows: few defects in a thin film; without a fixed charge; a low interface level with a semiconductor film; low leakage current; and the like. However, a gate leakage current tends to increase with a decrease in a film thickness of a gate insulating film. In addition, such a fine gate insulating film that can lower a gate leakage current is required in order to make the gate insulating film thinner. A field effect semiconductor device that can be driven with a low voltage and responds well to a high drive frequency can be obtained by making the gate insulating film thinner. Patent Document 1: Japanese Patent Laid-Open No. H6-188421 | <SOH> SUMMARY OF THE INVENTION <EOH>In the case of forming a silicon film over a transparent insulating substrate such as glass and manufacturing an integrated circuit by using the silicon film, a manufacturing technique developed in a large-scale integrated circuit using a single crystal silicon substrate cannot be diverted directly. This is because a processing temperature is restricted in terms of heat resistance of glass or the like that is a substrate over which an integrated circuit is formed as well as because of a crystallinity problem of a silicon film (polycrystalline silicon film or the like) for manufacturing an integrated circuit. A gate insulating film which is fine and has good electrical adequacy can be formed by a CVD method, but a film formation temperature is required to be equal to or more than 750° C. A plasma CVD method makes it possible to form a film at a low temperature; however, it is a problem that a film is damaged by a charged particle in plasma and a defect or a pinhole is easily caused. Further, in the case that a film formation temperature is equal to or less than 500° C., hydrogen is included within a film and film stability is decreased. On the contrary, a radio frequency sputtering method can form a thin film without hydrogen contamination. However, a film fine enough to be generally used as a gate insulating film is not obtained by a radio frequency sputtering method in comparison with a CVD method. Miniaturization of an element size is further required to manufacture a TFT having high switching speed that is essential for an element of a logic operation circuit and to obtain higher integration. A high-quality gate insulating film is essential to be formed to achieve the miniaturization. The gate insulating film is preferably heat-treated after the formation in order to form a high-quality gate insulating film. However, a substrate such as glass that expands or shrinks before or after applying a temperature above a strain point has a problem that misalignment occurs in patterning a film formed over the substrate. Therefore, it is difficult to heat-treat a gate insulating film at a temperature above a strain point of the substrate. A typical step of manufacturing a TFT over a glass substrate is described with reference to FIG. 7 . FIGS. 7 (E) to 7 (H) are top views, and FIGS. 7 (A) to 7 (D) are cross-sectional views along broken lines A-B and broken lines B-C in the respective top views. In FIG. 7 , steps of from forming a semiconductor film, element isolation to manufacturing a gate electrode are particularly described. First, a base film 11 and a semiconductor film 12 are formed over an insulating substrate 10 (FIGS. 7 (A) and 7 (E)). Subsequently, element isolation is performed by processing the semiconductor film 12 into island shapes to form a transistor formation region 13 and a transistor formation region 14 (FIGS. 7 (B) and 7 (F)). Subsequently, a gate insulating film 15 and a conductive film 16 are formed (FIGS. 7 (C) and 7 (G)). Lastly, the conductive film 16 is patterned to form a gate electrode 18 (FIGS. 7 (D) and 7 (H)). Note that a region of the gate insulating film 15 which is not overlapped with the gate electrode 18 is etched by etching in forming the gate electrode 18 , and it becomes a gate insulating film 17 . As described above, element isolation is performed on the semiconductor film 12 to be island shapes; then, the gate insulating film 15 and the conductive film 16 are formed. Thereafter, the conductive film 16 is patterned with the gate electrode 18 positioned to island-shaped semiconductor films, that is, the transistor formation regions 13 and 14 ; thus, a transistor is formed. In this method, an upper limit of a process temperature after processing the semiconductor film 12 into island shapes is determined by considering shrinkage of the substrate so that a defect due to misalignment in patterning is not caused. It is an object of the present invention to provide a thin film transistor which enables heat treatment aimed at improving characteristics of a gate insulating film such as lowering of an interface level or reduction in a fixed charge without causing a problem of misalignment in patterning due to expansion or shrinkage of a substrate such as glass and to provide a method for manufacturing the same. Means to Solve the Problem An invention of this specification is a thin film transistor comprising: an island-shaped semiconductor film and an island-shaped gate insulating film patterned by using the same photomask over an insulating substrate; a side wall made of an insulating material formed on a side face of the island-shaped semiconductor film; and a gate electrode formed over the island-shaped gate insulating film, characterized in that the gate electrode overlaps the side face of the island-shaped semiconductor film with the side wall therebetween. An invention of this specification is a thin film transistor comprising: an island-shaped semiconductor film and an island-shaped gate insulating film patterned by using the same photomask over an insulating substrate; a side wall made of an insulating material formed on side faces of the island-shaped semiconductor film and the island-shaped gate insulating film; and a gate electrode formed over the island-shaped gate insulating film, characterized in that the gate electrode overlaps the side face of the island-shaped semiconductor film with the side wall therebetween. An invention of this specification is a thin film transistor comprising: an island-shaped semiconductor film and an island-shaped gate insulating film patterned by using the same photomask over an insulating surface; and a gate electrode formed over the island-shaped gate insulating film, characterized in that a side face of the island-shaped semiconductor film is insulated, and the gate electrode overlaps the insulated side face of the island-shaped semiconductor film. An invention of this specification is a thin film transistor comprising: an island-shaped semiconductor film and an island-shaped gate insulating film patterned by using the same photomask over an insulating substrate; an insulating film patterned to cover side faces of the island-shaped semiconductor film and the island-shaped gate insulating film and only a peripheral portion of a top face of the island-shaped gate insulating film; and a gate electrode formed over the island-shaped gate insulating film, characterized in that the gate electrode overlaps the side face of the island-shaped semiconductor film with the insulating film patterned to cover the side faces of the island-shaped semiconductor film and the island-shaped gate insulating film and only the peripheral portion of the top face of the island-shaped gate insulating film therebetween. An invention of this specification is a method for manufacturing a thin film transistor, characterized by comprising the steps of: forming a semiconductor film over an insulating substrate; forming a first insulating film over the semiconductor film; heat-treating the semiconductor film and the first insulating film; forming an island-shaped semiconductor film and an island-shaped gate insulating film by patterning the semiconductor film and the first insulating film into island shapes with the use of the same photomask after the heat treatment; forming a second insulating film over the island-shaped gate insulating film; forming a side wall covering a side face of the island-shaped semiconductor film and a side face of the island-shaped gate insulating film in a self-aligned manner by anisotropically etching the second insulating film; forming a conductive film over the island-shaped gate insulating film after forming the side wall; and forming a gate electrode by patterning the conductive film. An invention of this specification is a method for manufacturing a thin film transistor, characterized by comprising the steps of: forming a semiconductor film over an insulating substrate; forming an insulating film over the semiconductor film; heat-treating the semiconductor film and the insulating film; forming an island-shaped semiconductor film and an island-shaped gate insulating film by patterning the semiconductor film and the insulating film into island shapes with the use of one resist mask after the heat treatment; insulating a side face of the semiconductor film by adding oxygen or nitrogen to the side face of the island-shaped semiconductor film without removing the resist mask; forming a conductive film over the island-shaped gate insulating film; and forming a gate electrode by patterning the conductive film. An invention of this specification is a method for manufacturing a thin film transistor, characterized by comprising the steps of: forming a semiconductor film over an insulating substrate; forming a first insulating film over the semiconductor film; heat-treating the semiconductor film and the first insulating film; forming an island-shaped semiconductor film and an island-shaped gate insulating film by patterning the semiconductor film and the first insulating film into island shapes with the use of one photomask after the heat treatment; forming a second insulating film over the island-shaped gate insulating film; patterning the second insulating film to cover edge portions of the island-shaped semiconductor film and the island-shaped gate insulating film and only a peripheral portion of a top face of the island-shaped gate insulating film; forming a conductive film over the island-shaped gate insulating film; and forming a gate electrode by patterning the conductive film. An invention of this specification is a method for manufacturing a thin film transistor, characterized by comprising the steps of: forming a semiconductor film over an insulating substrate; forming a first insulating film on the semiconductor film; forming a first conductive film over the first insulating film; heat-treating the semiconductor film, the first insulating film, and the first conductive film; forming an island-shaped semiconductor film, an island-shaped gate insulating film, and a first island-shaped conductive film by patterning the semiconductor film, the first insulating film, and the first conductive film into island shapes with the use of the same photomask after the heat treatment; forming a second insulating film over the first island-shaped conductive film; forming a side wall covering a side face of the island-shaped semiconductor film, a side face of the island-shaped gate insulating film, and a side face of the first island-shaped conductive film in a self-aligned manner by anisotropically etching the second insulating film; forming a second conductive film over the first island-shaped conductive film after forming the side wall; and forming a gate electrode by patterning the first island-shaped conductive film and the second conductive film. An invention of this specification is a method for manufacturing a thin film transistor, characterized by comprising the steps of: forming a semiconductor film over an insulating substrate; forming an insulating film over the semiconductor film; forming a first conductive film over the insulating film; heat-treating the semiconductor film, the insulating film, and the first conductive film; forming an island-shaped semiconductor film, an island-shaped gate insulating film, and a first island-shaped conductive film by patterning the semiconductor film, the insulating film, and the first conductive film into island shapes with the use of the same resist mask after the heat treatment; insulating a side face of the semiconductor film by adding oxygen or nitrogen to the side face of the island-shaped semiconductor film without removing the resist mask; forming a second conductive film over the first island-shaped conductive film; and forming a gate electrode by patterning the first island-shaped conductive film and the second conductive film. An invention of this specification is a method for manufacturing a thin film transistor, characterized by comprising the steps of: forming a semiconductor film over an insulating substrate; forming a first insulating film over the semiconductor film; forming a first conductive film over the insulating film; heat-treating the semiconductor film, the first insulating film, and the first conductive film; forming an island-shaped semiconductor film, an island-shaped gate insulating film, and a first island-shaped conductive film by patterning the semiconductor film, the first insulating film, and the first conductive film into island shapes with the use of the same photomask after the heat treatment; forming a second insulating film over the first island-shaped conductive film; patterning the second insulating film to cover edge portions of the island-shaped semiconductor film, the island-shaped gate insulating film, and the first island-shaped conductive film and only a peripheral portion of a top face of the first island-shaped conductive film; forming a second conductive film over the island-shaped gate insulating film; and forming a gate electrode by patterning the first conductive film and the second conductive film. A method for manufacturing a thin film transistor according to the invention of this specification further is characterized by comprising the steps of: heat-treating in a state where at least a gate insulating film is formed over a semiconductor film on which element isolation is not performed; isolating the gate insulating film and the semiconductor film into an element structure by using one photomask after the heat treatment; forming an insulating film covering a side face of an exposed semiconductor film; and forming a gate electrode over the gate insulating film. Expansion or shrinkage of a substrate such as glass during the heat treatment can be prevented from affecting misalignment in patterning since the gate insulating film and the semiconductor film are simultaneously patterned and processed into element shapes after the heat treatment. The side face of the semiconductor film is exposed in a condition that the gate insulating film and the semiconductor film are simultaneously patterned and processed into element shapes. Then, one feature is that an insulating film covering the side face of the semiconductor film is formed before forming an electrode such as a gate electrode or a wiring over the gate insulating film. Thus, a short circuit is prevented between the semiconductor film that is processed into an element structure and an electrode or a wiring to be formed over the gate insulating film. In the invention of this specification, a substrate having a lower strain point than a heat treatment temperature of from 600° C. to 800° C. to be applied to a gate insulating film is effectively used as an insulating substrate over which a thin film transistor is formed, regardless of its type. Further, a laminated film of a semiconductor film and a gate insulating film on which element isolation is not performed is simultaneously heat-treated in the invention of this specification. Furnace or RTA (Rapid Thermal Anneal) may be used for the heat treatment. Either gas heating or lamp heating can be used in RTA treatment. Preferably, lamp heating treatment may be performed with up to a conductive film for forming at least one part of a gate electrode formed over the laminated film. In the case of using a halogen lamp having a peak of an emitted spectrum in an infrared region, the conductive film effectively absorbs emitted light. Not only can the gate insulating film be effectively heated, but also an interface between the gate insulating film and the conductive film can be heat-treated. Consequently, characteristics such as reduction in a leakage current resulting from the interface between the gate electrode and the gate insulating film can be improved. A side face of the semiconductor film is exposed in the case of simultaneously performing element isolation on the laminated film including the semiconductor film and the gate insulating film. Therefore, the side face of the semiconductor film is short-circuited with the gate electrode in the case of successively forming a conductive film for forming the gate electrode. Particularly, the side face of the semiconductor film and a portion for leading the gate electrode outside the semiconductor film on which element isolation is performed are short-circuited. Then, an insulating film covering the side face of the semiconductor film is required. The insulating film covering the side face of the semiconductor film can be formed by forming an insulating film covering an entire surface of the substrate over patterned semiconductor film and gate insulating film, anisotropically etching the insulating film, and processing into a side wall shape in a self-aligned manner. In addition, a method for insulating the side face of the semiconductor film at a low temperature or a method for patterning the insulating film to cover side faces of the semiconductor film and the gate insulating film and only a peripheral portion of a top face of the gate insulating film is given as another method for forming the insulating film covering the side face of the semiconductor film. The insulating film covering the side face of the semiconductor film can be formed to have higher precision since there is no misalignment in the case of forming in a self-aligned manner. Therefore, in the case of intending integration, it is preferable to manufacture the insulating film by a method for forming into a side wall shape or a method for insulating the side face of the semiconductor film at a low temperature. In this way, the insulating film is formed only on a desired side face of a semiconductor film. According to the present invention having the above structures, a gate insulating film can be heat-treated without a problem of an alignment defect in patterning even at a temperature of 700° C. that conventionally causes a problem of misalignment in patterning due to shrinkage of a substrate such as glass. In the present invention, a gate insulating film can be heat-treated at a temperature of 700° C. above a strain point of a substrate such as glass. Therefore, an interface level is lowered; a fixed charge is reduced; a gate leakage current is lowered; field-effect mobility, subthreshold coefficient, and the like become favorable; a change of transistor characteristics over time during continuous operation can be reduced; a yield is improved; and variation in the characteristics is reduced, in a thin film transistor. | 20040409 | 20080520 | 20050120 | 74555.0 | 0 | PERKINS, PAMELA E | THIN FILM TRANSISTOR, ELECTRONIC DEVICE HAVING THE SAME, AND METHOD FOR MANUFACTURING THE SAME | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,821,212 | ACCEPTED | Linerless web utilizing apparatus and methods | There is disclosed a printer with an arrangement for assuring that a linerless tacky adhesive-backed web is reliably fed. The printer has stripper elements which terminate at tip portions which extend into the platen roll to initially cut grooves in the platen roll, and because the tip portions extend below the outer periphery of the platen roll into these grooves, the stripper elements continue to strip the web reliably from the platen roll during subsequent printing cycles. | 1. Method, comprising: providing an adhesive-resistant, elastomeric, rotatable platen roll for a printer, providing a web stripper having at least one tip portion positioned to cut at least one circumferential groove in the outer surface of the platen roll, and rotating the platen roll to cut the groove(s). 2. Method as defined in claim 1, including providing a thermal print head cooperable with the platen roll, providing a web positioned between and in contact with the print head and the platen roll, and the web moves in contact with the rotating platen roll. 3. Method as defined in claim 1, wherein the tip portion is sharp. 4. Method as defined in claim 1, wherein the tip portion is pointed. 5. Method as defined in claim 1, including providing a thermal print head cooperable with the platen roll, providing a web positioned between and in contact with the print head and the platen roll, wherein the web has a coating of tacky adhesive in contact with the platen roll, and printing on the web while the web moves and while the tip portion (s) cuts (or cut) the groove(s) in the rotating platen roll. 6. Method as defined in claim 1, including providing a thermal print head cooperable with the platen roll, and printing on a web positioned between and in contact with the print head and the platen roll after the groove(s) has (or have) been cut, and wherein the web has a coating of tacky adhesive contacting the platen roll. 7. Method as defined in claim 1, including providing a linerless web having a printable face side and an underside with a tacky adhesive positioned with the print head cooperable with the printable face side and the platen roll in contact with the adhesive, and printing on the web after the groove(s) has (or have) been cut. 8. Method defined in claim 1, wherein the groove(s) is (are) small enough so as not to degrade print quality when printing on a linerless web having tacky adhesive in contact with the platen roll. 9. Method, comprising: providing an adhesive-resistant, elastomeric, rotatable platen roll for a printer, providing a web stripper having at least one tip portion, and positioning the stripper with the tip portion (s) digging into or locally depressing the outer surface of the platen roll so that upon rotation of the platen roll each tip portion will cut a circumferential groove in the outer surface of the platen roll. 10. Method as defined in claim 9, wherein each groove is no wider than the respective tip portion. 11. Method as defined in claim 9, wherein there are a plurality of grooves and the grooves are essentially the same size. 12. Method defined in claim 9, wherein the groove(s) is (are) small enough so as not to degrade print quality when printing on a linerless web having tacky adhesive in contact with the platen roll. 13. Method, compromising: providing an adhesive-resistant, elastomeric roll for contacting adhesive on a linerless web, providing a web stripper having at least one tip portion positioned to cut at least one circumferential groove in the outer surface of the roll, and rotating the roll to cut the groove(s). 14. Method as defined in claim 13, including printing on the web while the roll is rotating and while the stripper tip portion(s) is (or are) in the groove(s). 15. Method as defined in claim 13, wherein the tip portion(s) remain in the groove(s) during subsequent rotation of the roll. 16. Method defined in claim 13, wherein the groove(s) is (are) small enough so as not to degrade print quality when printing on a linerless web having tacky adhesive in contact with the platen roll. 17. Method, comprising: providing an adhesive-resistant, elastomeric roll for contacting adhesive on a linerless web, providing a web stripper having at least one tip portion, positioning the stripper with the tip portion(s) digging into or locally depressing the outer surface of the roll so that upon rotation of the roll each tip portion will cut a circumferential groove in the outer surface of the roll. 18. In or for a printer: a print head and a cooperable platen roll for printing on a linerless web having a printable face side and an underside with a tacky adhesive, the platen roll having an adhesive-resistant elastomeric outer surface, and a web stripper with a tip portion positioned to cut at least one circumferential groove in the outer surface of the platen roll. 19. In or for a printer: a print head and a cooperable platen roll for printing on a web of linerless label material with a printable face side and an underside with the tacky adhesive, the platen roll having an adhesive-resistant elastomeric outer surface, at least one circumferential groove in the outer surface of the platen roll, and a web stripper having at least one tip portion extending into the groove(s). 20. In or for a printer as defined in claim 15, wherein the groove(s) is (are) no wider than the tip portion(s). 21. In or for a printer: a print head and a cooperable platen roll for printing on a linerless label material web with a printable face side and an underside with a tacky adhesive, the platen roll having an adhesive-resistant outer surface, a plurality of laterally spaced circumferential grooves in the outer surface of the platen roll, and a plurality of web stripper members with tip portions extending into the grooves. 22. In or for printer as defined in claim 21, wherein the grooves are no wider than the tip portions. 23. In a printer: a print head and a cooperable platen roll for printing on a web of linerless label material with a printable face side and an underside with a tacky adhesive, the platen roll having an adhesive-resistant elastomeric outer surface, and a web stripper having at least one portion positioned to cut at least one circumferential groove in the outer surface of the platen roll. 24. Method defined in claim 23, wherein the groove(s) is (are) small enough so as not to degrade print quality when printing on a linerless web having tacky adhesive in contact with the platen roll. 25. In or for a printer as defined in claim 23, and using the print head and platen roll to print on a linerless web while the tip portion(s) is (are) in the groove(s). 26. In combination: a roll having an adhesive-resistant, elastomeric outer surface for contacting tacky adhesive on a linerless web, and a stripper with a tip portion positioned to cut at least one circumferential groove in the outer surface of the platen roll and to facilitate stripping the web from the roll. 27. In combination: a roll having an adhesive-resistant, elastomeric outer surface for contacting tacky adhesive on a linerless web, at least one circumferential groove in the outer surface of the roll, and a web stripper having at least one tip portion extending into one of the grooves to facilitate stripping the web from the roll. 28. In combination: a roll having an adhesive-resistant, elastomeric outer surface for contacting tacky adhesive on a linerless web, and a stripper having at least one tip portion locally dug or pressed into the outer surface of the roll so that upon rotation of the roll the tip portion(s) will cut a groove or grooves into the roll to facilitate stripping of the web from the roll. 29. In combination: a printer including a frame, a laterally extending platen roll, a print head cooperable with the platen roll, a shelf having a plurality of laterally spaced supporting elements, the shelf became constructed of plastics material, a rigid bar having end portions connected to the frame, the shelf being connected securely to the bar. 30. The combination defined in claim 29, wherein the supporting elements include cutters positioned to cut grooves in the outer surface of the platen roll and to assist in stripping the web from the platen roll. | BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to printers for handling webs including linerless webs having tacky adhesive, methods associated with the handling of such webs, rolls including platen rolls, and methods of making rolls. 2. Brief Description of the Prior Art The following documents are made of record: U.S. Pat. Nos. 5,267,800; 5,497,701; 5,833,377; 6,585,437; U.S. patent application Ser. No. 10/266,060, filed Oct. 7, 2002; and Linerless Addendum, Monarch Marking Systems, Inc. 1998. SUMMARY OF THE INVENTION The present invention relates to improved method and apparatus to strip a tacky adhesive-backed web from a roll reliably. It is a feature of the invention to provide an improved printer for handling linerless, tacky, adhesive-backed webs wherein the webs are reliably stripped from a roll. It is a feature of the invention to provide an improved printer for printing on a linerless web backed by a tacky adhesive which has a thermal print head and an adhesive-resistant, elastomeric, rotatable platen roll with a web stripper having at least one tip portion to cut at least one circumferential groove in the outer surface of the platen roll upon rotation of the platen roll. Initially, the tip portion or portions are positioned to dig or locally press into the elastomer platen roll. Upon rotation of the platen roll, a circumferential groove or grooves are cut in the surface of the platen roll. From the very beginning, the stripper causes the web to be reliably stripped from the roll. Repeated rotation of the platen roll completes the formation of the groove or grooves as the elastomeric material is cut and/or abraded away. After the groove or grooves have been cut, the linerless web continues to be reliably stripped from the web. It is apparent that the groove or grooves are no wider or deeper than the tip portions that penetrate into the elastomeric material below the outer surface. Indeed, the tip portions “write their own name” in the platen roll, and the grooves are perfectly aligned with the tip portions which formed the grooves. It is a feature of the invention to provide a stripper with one or more tip portions or cutters which serve to help strip the tacky, adhesive-backed web from the roll and which also function to make the groove(s) in the roll. It is a feature of the invention to provide an improved, low friction shelf for a linerless printer which is relatively wide but which is rigid enough to resist flexure during use so that a linerless tacky adhesive-backed web is incapable of bowing the shelf and following the platen roll around. BRIEF DESCRIPTION OF THE DIAGRAMMATIC DRAWINGS FIG. 1 is a perspective view of a printer for handling a linerless web backed with tacky adhesive; FIG. 2 is a fragmentary top plan view of the platen roll and the stripper elements initially dug or pressed into the platen roll; FIG. 3 is a fragmentary top plan view similar to FIG. 2 but showing the platen roll after the platen roll has been rotated to form the grooves in the platen roll; FIG. 4 is a sectional view taken through the stripper, the bar, the platen roll and the print head; and FIG. 5 is an exploded perspective view of a shelf with strippers or stripper elements terminating at tip portions or cutters and a bar for strengthening and mounting the shelf. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIG. 1, there is shown a portion of a printer generally indicated at 13 for printing on a linerless web generally indicated at 10 in printing cooperation with a print head 16 and a cooperating roll generally indicated at 17, in particular a platen roll. The web 10 can be either imperforate or it can be provided with longitudinally spaced transverse perforations (not shown) which define labels. The print head 16 is preferably a thermal print head but other types of print heads can be used. The platen roll 17 is composed of an elastomeric material such as silicone rubber and/or outer surface 17′ of the platen roll 17 can be coated to be adhesive resistant. An elastomeric material is most preferred for a platen roll used with a thermal print head because it provides slightly yieldable support and counterpressure to the print head 16, and it is resilient so as to be forgiving particularly in the event of slight misalignment of the print head 16 and the platen roll 17. The web 10 has an upper face 11 with the usual coatings such as a thermal coating, an optional barrier coating and a silicone coating. The underside of the web 12 has a coating of adhesive 14 which can be uniform and continuous as shown, which is known as a “full gum” coating, but the coating of adhesive 14 can be patterned or a “part gum” coating which is useful in certain applications. The adhesive 14 is of the tacky type also known as “pressure sensitive adhesive” because it adheres to a surface when pressure is applied. Tacky adhesive is sticky or tacky without activation by heat, water or other medium. Because rolls that are to be in contact with adhesive on one side of a linerless web are typically adhesive resistant, when such rolls become worn the adhesive on the linerless web adheres more tenaciously to the worn roll and the linerless web has a tendency to follow the roll around. The web may bunch up or buckle between the platen roll and a stripper even though the stripper is immediately adjacent to or touches the platen roll. When the linerless web adheres to the platen roll there is also a tendency of the buckled linerless web to push against the stripper or to bow the stripper to make an easier throat between the platen roll and the stripper through which the linerless web can pass. According to the invention, there is provided a support 18 with parallel support elements or members 19 which, as shown in FIG. 4, support the web following printing by the print head 16. The support elements 19 have tip portions 20. The tip portions 20 are preferably both sharp and pointed and terminate at laterally aligned points 21. The tip portions 20-are used to cut circumferential grooves 22 in the outer surface or periphery 17′ of the platen roll 17, and thus the tip portions are cutters that cut the grooves 22. The tip portions 20 are those portions of the elements 19 that extend into the grooves 22. The tip portions 20 act initially as cutters. The elements 19 including their tip portions 20 act as strippers that help strip the web 10 from the platen roll 17. FIG. 4 shows that the elements 19 enter the grooves 22 essentially tangent to the surface of the outer surface 17′, and more particularly, near the top of the outer surface 17′. Initially, the support 18 is positioned so that the points 21 depress and dig into the outer surface 17′ of the platen roll 17 as illustrated in FIG. 2. Upon rotation of the platen roll 17, the tip portions or cutters 20 cut the grooves 22 as best shown in FIGS. 1 and 3. Once positioned as indicated above, the tip positions 20 can remain positioned in the grooves 22 throughout use of the printer 13. The tip portions 20 are slightly below the outer surface 17′ of the roll 17. Because the tip portions 20 are below the outer surface 17′ in the grooves 22, the linerless web 10 cannot go between the roll 17 and the element 19. Yet the grooves 22 are small enough so that the grooves 22 do not degrade the print quality. The grooves 22 are narrow enough and the web 10 is thick enough so that the web 10 remains well supported, and there is no tendency of the web 10 to take on an undulating configuration. It is preferred that the grooves 22 are of equal width and depth. The grooves 22 are no wider than the tip portions 20. There is no clearance between the sides of the tip portions 20 and the grooves 22, and there is no clearance between the tips 21 and the bottoms of the grooves 22. Once the tip portions are positioned to cut the grooves 22, they are in perfect alignment with the grooves formed by the tip portions 22, and there is therefore no need to adjust or reposition the stripper 18 with respect to the roll 17. By way of example, not limitation, the grooves are most preferably about 0.125 mm wide and about 0.125 mm deep. A typical web 10 is about 0.1 mm thick. The stripper elements 19 are blades or are blade-like in construction. The upper configuration of each element 19 is preferably inverted V-shaped as shown and terminates in a longitudinally extending linear or straight line-shaped edge as indicated at 19′. The elements 19 terminate at the points 21. The sides 23 of the elements 19 that face the platen roll 17 are arcuate and terminate at the points 21. The elements 19 are preferably equally spaced. The adhesive 14 of the web 10 contacts the edges 19′ and the web 10 is accordingly supported by the edges 19′ which exert only minimal drag on the web 10 as the web 10 advances. The elements 19 are molded integrally with a bar portion 24 having ribs 25. The side of the bar portion 24 opposite the ribs 25 has spaced ribs 26. The bar portion 24 has three laterally spaced, oversize through-holes 27. The support or stripper 18 has a groove 28 disposed between the elements 19 and the ribs 25. A rigid metal bar generally indicated at 29 is received in the groove 28. The bar 29 is a composite comprised of a bar member 30 and a bar member 31 welded to the bar member 30. Internally threaded fasteners 32 pass through and are secured in aligned holes 33 and 34 in the bar members 30 and 31. Screws 35 pass through the holes 27 and are threaded into the threaded fasteners 32. The bar portion 24 and the composite bar 29 are clamped together by the head of the screw 35 and the fastener 32. Because of the clearances between the groove 28 and the bar 29 and between the holes 27 and the screws 35, the stripper 18 can be precisely positioned or adjusted manually so that the tip portions 20 penetrate or dig into the outer surface 17′ to the desired depth. While the one-piece molded stripper 18 is rigid, the bar 29 adds rigidity and thus helps to maintain the tip portions 20 positioned in the grooves 22. As shown, the bar 29 is mounted in frame plates 36 and 37 of the printer frame 38. End portion 39 of the bar 29 hooks into the frame plate 36, and end portion 40 snaps into a clip 41 screwed to the frame plate 37. Further aspects of the printer 13 are shown in U.S. Pat. No. 5,833,377 incorporated herein by reference. The frame plates 36 and 37 in the present application correspond to walls 126 and 127 in U.S. Pat. No. 5,833,377. The platen roll 17 is preferably comprised of a metal shaft 42 on which an elastomeric sleeve 43 is secured. The shaft is 42 preferably driven as illustrated in U.S. Pat. No. 5,833,377 while the thermal print head 16 prints in the web 10. As the platen roll 17 rotates, the web 10 is stripped from the roll 17 by the stripper elements 19, and the printed, stripped web 10 passes over the elements 19 with the adhesive 14 in contact with upper edges 19′ of the elements 19. As shown in FIG. 4, the web 10 preferably follows a slightly downward trajectory as it is stripped from the platen roll 17 and is supported by elements 19. The tip portions or cutters 20 cut the circumferential grooves by wearing away quite narrow circumferential zones of the outer portion of the sleeve 43 with relatively few rotations of the roll 17. While the invention is applied to a platen roll 17 it is also useful when stripping adhesive-backed webs for various rolls other than platen rolls. By way of example, not limitation, for a web which is about 102 mm wide, it is most preferred to use 14 stripper elements, however a greater or lesser number can be used. It is also within the spirit of the invention to have less than all the elements 19 extend into the grooves 22. While the stripper 18 is stiffened or strengthened by the bar 29, the stripper 18 could be made stronger by making it from thicker plastics material and suitably mounting it to the frame plates 36 and 37. While the stripper 18 is preferably of one-piece molded plastics construction, the stripper 18 can be made in multiple parts. The preferred illustrated shape of the tip portion 20 is such that if the platen roll 17 is to be rotated in the reverse direction from that shown by arrow A in FIG. 1 to bring the web 10 to the top-of-form position, no harm will come to the platen roll 17. While the invention is particularly useful for use with linerless, tacky adhesive-backed, printable webs, the method and While the invention is particularly useful for use with linerless, tacky adhesive-backed, printable webs, the method and apparatus of the invention can also be used with adhesive webs having siliconized release liners. Other embodiments and modifications of the invention will suggest themselves to those skilled in the art, and all such of these as come within the spirit of this invention are included within its scope as best defined by the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention This invention relates to printers for handling webs including linerless webs having tacky adhesive, methods associated with the handling of such webs, rolls including platen rolls, and methods of making rolls. 2. Brief Description of the Prior Art The following documents are made of record: U.S. Pat. Nos. 5,267,800; 5,497,701; 5,833,377; 6,585,437; U.S. patent application Ser. No. 10/266,060, filed Oct. 7, 2002; and Linerless Addendum, Monarch Marking Systems, Inc. 1998. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention relates to improved method and apparatus to strip a tacky adhesive-backed web from a roll reliably. It is a feature of the invention to provide an improved printer for handling linerless, tacky, adhesive-backed webs wherein the webs are reliably stripped from a roll. It is a feature of the invention to provide an improved printer for printing on a linerless web backed by a tacky adhesive which has a thermal print head and an adhesive-resistant, elastomeric, rotatable platen roll with a web stripper having at least one tip portion to cut at least one circumferential groove in the outer surface of the platen roll upon rotation of the platen roll. Initially, the tip portion or portions are positioned to dig or locally press into the elastomer platen roll. Upon rotation of the platen roll, a circumferential groove or grooves are cut in the surface of the platen roll. From the very beginning, the stripper causes the web to be reliably stripped from the roll. Repeated rotation of the platen roll completes the formation of the groove or grooves as the elastomeric material is cut and/or abraded away. After the groove or grooves have been cut, the linerless web continues to be reliably stripped from the web. It is apparent that the groove or grooves are no wider or deeper than the tip portions that penetrate into the elastomeric material below the outer surface. Indeed, the tip portions “write their own name” in the platen roll, and the grooves are perfectly aligned with the tip portions which formed the grooves. It is a feature of the invention to provide a stripper with one or more tip portions or cutters which serve to help strip the tacky, adhesive-backed web from the roll and which also function to make the groove(s) in the roll. It is a feature of the invention to provide an improved, low friction shelf for a linerless printer which is relatively wide but which is rigid enough to resist flexure during use so that a linerless tacky adhesive-backed web is incapable of bowing the shelf and following the platen roll around. | 20040408 | 20070306 | 20051013 | 74554.0 | 0 | EVANISKO, LESLIE J | LINERLESS WEB UTILIZING APPARATUS AND METHODS HAVING DUAL FUNCTION STRIPPER ELEMENT | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,821,225 | ACCEPTED | Process for making dialkyl carbonates | A process for the production of dialkyl carbonates from the reaction of alcohol, for example C1-C3 alcohols, with urea is disclosed wherein the water and ammonium carbamates impurities in the feed are removed in a prereactor. The water is reacted with urea in the feed to produce ammonium carbamate which is decomposed along with the ammonium carbamates originally in the feed to ammonia and carbon dioxide. In addition some of the urea is reacted with the alcohol in the first reactor to produce alkyl carbamate which is a precursor to dialkyl carbonate. Dialkyl carbonates are produced in the second reaction zone. The undesired by-product N-alkyl alkyl carbamates are continuously distilled off from the second reaction zone along with ammonia, alcohol and dialkyl carbonates under the steady state reactor operation. N-alkyl alkyl carbamates can be converted to heterocyclic compounds in a third reaction zone to remove as solids from the system. | 1. A process for the production of dialkyl carbonate comprising the steps of: (a) feeding a stream comprising urea, alcohol, water and ammonium carbamate to a first reaction zone: (b) concurrently in said first reaction zone, (i) reacting water with urea to form ammonium carbamate, (ii) decomposing ammonium carbamate into ammonia and carbon dioxide, and (c) removing ammonia, carbon dioxide and alcohol from said first reaction zone; (d) removing urea and alcohol from said first reaction zone; (e) feeding said urea and alcohol to a second reaction zone; (f) reacting alcohol and urea in the presence of a homogeneous catalyst comprising an organotin complex compound of dialkylalkoxide in a high boiling solvent to form dialkyl carbonate and (g) removing dialkyl carbonate and alcohol from said second reaction zone. 2. The process according to claim 1 wherein alcohol and urea react to form alky carbamate in said first reaction zone. 3. The process according to claim 1 wherein said alcohol is a C1-C3 alcohol. 4. The process according to claim 1 comprising: (a) feeding said stream containing urea, methanol, water and ammonium carbamate to a first reaction zone: (b) concurrently in said first reaction/distillation zone, (i) reacting water with urea to form ammonium carbamate, (ii) decomposing the ammonium carbamate in the feed and the ammonium carbamate from the reaction of water with urea into ammonia and carbon dioxide, and (iii) separating the ammonia, carbon monoxide and methanol from the urea and by distillation; (c) removing ammonia, carbon dioxide and methanol from said first reaction/distillation zone as a first overheads; (d) removing urea and methanol from said first reaction/distillation zone as a first bottoms; (e) feeding said first bottoms and methanol to a second reaction/distillation zone; (f) concurrently in said second reaction/distillation zone, (i) reacting methanol and urea in the presence of a homogeneous catalyst comprising an organotin complex compound of dialkylmethoxide in a high boiling solvent to form dimethyl carbonate and (ii) separating dimethyl carbonate and ammonia from the homogeneous catalyst by distillation. (g) removing dimethyl carbonate and methanol from said second reaction/distillation zone as a second overheads; and (h) removing a second bottoms from said second distillation column reactor. 5. The process according to claim 4 wherein the dimethyl carbonate in said second overheads is separated from the methanol by extractive distillation. 6. The process according to claim 4 wherein an inert diluent is added to said first overheads. 7. The process according to claim 4 wherein the methanol in said first overheads is condensed and a portion of said condensed methanol is returned to near the top of said first distillation column reactor as reflux and the remainder of said condensed methanol is returned to the lower section of said first distillation column reactor. 8. The process according to claim 4 wherein a first portion of said second bottoms is fed to said first distillation column reactor, a second portion of said second bottoms is recycled to said second distillation column and a third portion of said second bottoms is fed to a third distillation column reactor for catalyst regeneration and heavies cleanup. 9. The process according to claim 4 wherein said second overheads is condensed and a portion of said condensed second overheads is returned to said second distillation column reactor as reflux. 10. A process for the production of dimethyl carbonate comprising the steps of: (a) feeding a stream containing urea, methanol, water and ammonium carbamate to a first distillation column reactor: (b) concurrently in said first distillation column reactor, (i) reacting a portion of said urea with a portion of said methanol to produce methyl carbamate, (ii) reacting water with urea to form ammonium carbamate, (iii) decomposing the ammonium carbamate in the feed and the ammonium carbamate from the reaction of water with urea into ammonia and carbon dioxide, and (iv) separating the ammonia, carbon monoxide and methanol from the urea and methyl carbamate by distillation; (c) removing ammonia, carbon dioxide and methanol from said first distillation column reactor as a first overheads; (d) removing urea and methyl carbamate from said distillation column reactor as a first bottoms; (e) feeding said first bottoms and methanol to a second distillation column reactor; (f) concurrently in said second distillation column reactor, (i) reacting methanol and urea in the presence of a homogeneous catalyst comprising an organotin complex compound of dialkylmethoxide in a high boiling solvent to form dimethyl carbonate and (ii) separating dimethyl carbonate and ammonia from the homogeneous catalyst by distillation; (g) removing dimethyl carbonate and methanol from said second distillation column reactor as a second overheads; (h) removing homogeneous catalyst from said second distillation column reactor as a second bottoms; (i) separating the dimethyl carbonate from the methanol in said second overheads by extractive distillation; and (j) feeding a first portion of said second bottoms to said first distillation column reactor; (k) feeding a second portion of said second bottoms to a third distillation column reactor where the catalyst is regenerated and cleaned up of heavies; and (l) recycling a third portion of said second bottoms to said second distillation column reactor. 11. in a process for the production of dialkyl carbonates by the reaction of reactants comprising urea and alcohol having water and ammonium carbonate as impurities comprising the steps of: (a) feeding reactants comprising urea and alcohol to a primary reaction zone; (b) feeding an organotin compound and a high boiling electron donor atom containing solvent to said primary reaction zone; and (c) concurrently in said primary reaction zone (i) reacting alcohol and urea in the presence of said organotin compound and said high boiling electron donor atom containing solvent to produce dialkyl carbonate; and (ii) removing the dialkyl carbonate and ammonia from said primary reaction zone as vapor, wherein the improvement is the use of a preliminary reaction zone before the primary reaction zone to remove water, and ammonium carbamate from said reactants, by feeding the reactants, first to the preliminary reaction zone under conditions to react said water with urea to form ammonium carbamate and decompose ammonium carbamate to ammonia and carbon dioxide and removing the ammonia and carbon dioxide from said reactants prior to feeding the reactants in step (a). 12. The process according to claim 11 where the temperature of the preliminary reaction zone is at a temperature in the range from 200 to 380° F. in liquid phase. 13. The process according to claim 12 where the temperature of the preliminary reaction zone is in the range of from 250 to 350° F. 14. The process according to claim 11 wherein a portion of the methanol feed reacts with a portion of the urea feed to form methyl carbamate in the preliminary reaction zone. 15. The process according to claim 11 wherein the preliminary reaction zone and primary reaction zone are operated under distillation conditions. 16. The process according to claim 11 wherein the water is removed from the feeds by reacting it with urea to form ammonium carbamate which in turn decomposes to ammonia and carbon dioxide. 17. The process according to claim 16 where the temperature of the preliminary reaction zone is at a temperature in the range from 200 to 380° F. in liquid phase. 18. The process according to claim 11 wherein the ammonium carbamates are removed from the feeds by decomposition to ammonia and carbon dioxide. 19. The process according to claim 18 wherein the temperature of the preliminary reaction zone is at a temperature in the range from 200 to 380° F. in liquid phase. 20. The process according to claim 11 wherein the said high boiling electron donor atom compound comprises triethylene glycol dimethyl ether. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for the production of dialkyl carbonates, particularly C1-C3 dialkyl carbonates wherein the reaction occurs simultaneously with separation of the reactants and the carbonate products. More particularly the invention relates to a process wherein alcohol is reacted with urea and/or alkyl carbamate in the presence of a complex compound catalyst. More particularly the invention relates to a process wherein feed stream impurities are removed to produce stable catalyst performance, improved reaction rates and trouble free downstream operation of equipment. 2. Related Art Dialkyl carbonates are important commercial compounds, the most important of which is dimethyl carbonate (DMC). Dimethyl carbonate is used as a methylating and carbonylating agent and as a raw material for making polycarbonates. It can also be used as a solvent to replace halogenated solvents such as chlorobenzene. Although the current price of both dimethyl carbonate and diethyl carbonate is prohibitively expensive to use as fuel additive, both could be used as an oxygenate in reformulated gasoline and an octane component. Dimethyl carbonate has a much higher oxygen content (53%) than MTBE (methyl tertiary butyl ether) or TAME (tertiary amyl methyl ether), and hence not nearly as much is needed to have the same effect. It has a RON of 130 and is less volatile than either MTBE or TAME. It has a pleasant odor and, unlike ethers, is more readily biodegradable. In older commercial processes dimethyl carbonate was produced from methanol and phosgene. Because of the extreme toxicity and cost of phosgene, there have been efforts to develop better, non-phosgene based processes. In one new commercial process, dimethyl carbonate is produced from methanol, carbon monoxide, molecular oxygen and cuprous chloride via oxidative carbonylation in a two-step slurry process. Such a process is disclosed in EP 0 460 735 A2. The major shortcomings of the process are the low production rate, high cost for the separation of products and reactants, formation of by-products, high recycle requirements and the need for corrosion resistant reactors and process lines. Another new process is disclosed in EP 0 742 198 A2 and EP 0 505 374 B1 wherein dimethyl carbonate is produced through formation of methyl nitrite instead of the cupric methoxychloride noted above. The by-products are nitrogen oxides, carbon dioxide, methylformate, etc. Dimethyl carbonate in the product stream from the reactor is separated by solvent extractive distillation using dimethyl oxalate as the solvent to break the azeotropic mixture. Although the chemistry looks simple and the production rate is improved, the process is very complicated because of the separation of a number of the materials, balancing materials in various flow sections of the process, complicated process control and dealing with methyl nitrite, a hazardous chemical. In another commercial process dimethyl carbonate is produced from methanol and carbon dioxide in a two-step process. In the first step cyclic carbonates are produced by reacting epoxides with carbon dioxide as disclosed in U.S. Pat. Nos. 4,786,741; 4,851,555 and 4,400,559. In the second step dimethyl carbonate is produced along with glycol by exchange reaction of cyclic carbonates with methanol. See for example Y. Okada, et al “Dimethyl Carbonate Production for Fuel Additives”, ACS, Div. Fuel Chem., Preprint, 41(3), 868, 1996, and John F. Knifton, et al, “Ethylene Glycol-Dimethyl Carbonate Cogeneration”, Journal of Molecular Chemistry, vol. 67, pp 389-399, 1991. While the process has its advantages, the reaction rate of epoxides with carbon dioxide is slow and requires high pressure. In addition, the exchange reaction of the cyclic carbonate with methanol is limited by equilibrium and methanol and dimethyl carbonate form an azeotrope making separation difficult. It has been known that dialkyl carbonates can be prepared by reacting primary aliphatic alcohols such as methanol with urea (1) in the presence of various heterogeneous and homogeneous catalysts such as dibutyltin dimethoxide, tetraphenyltin, etc. See for example P. Ball et al, “Synthesis of Carbonates and Polycarbonates by Reaction of Urea with Hydroxy Compounds”, C1 Mol. Chem., vol. 1, pp 95-108, 1984. Ammonia is a coproduct and it may be recycled to urea (2) as in the following reaction sequence. Carbamates are produced at a lower temperature followed by production of dialkyl carbonates at higher temperature with ammonia being produced in both steps. As noted the above two reactions are reversible under reaction conditions. The order of catalytic activity of organotin compounds is R4Sn<R3SnX<<R2SnX2, wherein X=Cl, RO, RCOO, RCOS. A maximum reaction rate and minimum formation of by-products are reported for dialkyl tin (IV) compounds. For most catalysts (Lewis acids), higher catalyst activity is claimed if the reaction is carried out in the presence of an appropriate cocatalyst (Lewis base). For example, the preferred cocatalyst for organic tin (IV) catalysts such as dibutyltin dimethoxide, dibutyltin oxide, etc. are triphenylphosphine and 4-dimethylaminopyridine. However, thermal decomposition of intermediate alkyl carbamates and urea to isocyanic acid (HNCO) or isocyanuric acid ((HNCO)3) and alcohol or ammonia (a coproduct of urea decomposition) is also facilitated by the organotin compounds such as dibutyltin dimethoxide or dibutyltin oxide employed in the synthesis of dialkyl carbamates. WO 95/17369 discloses a process for producing dialkyl carbonate such as dimethyl carbonate in two steps from alcohols and urea, utilizing the chemistry and catalysts published by P. Ball et al. In the first step, alcohol is reacted with urea to produce an alkyl carbamate. In the second step, dialkyl carbonate is produced by reacting further the alkyl carbamate with alcohol at temperatures higher than the first step. The reactions are carried out by employing an autoclave reactor. However, when methanol is reacted with methyl carbamate or urea, N-alkyl by-products such as N-methyl methyl carbamate (N-MMC) and N-alkyl urea are also produced according to the following reactions: The dialkyl carbonate is present in the reactor in an amount between 1 and 3 weight % based on total carbamate and alcohol content of the reactor solution to minimize the formation of the by-products. In U.S. Pat. No. 6,010,976, dimethyl carbonate (DMC) is synthesized from urea and methanol in high yield in a single step in the presence of high boiling ethers and a novel homogeneous tin complex catalyst. (NH2)2CO+2CH3OH=====>(CH3O)2CO+2NH3 The ether solvent also serves as complexing agent to form the homogenous complex catalyst from dibutyltin dimethoxide or oxide in situ. The separation of materials involved in the DMC processes is very important for the commercial production of DMC for economic reasons. EP 0 742 198 AI and U.S. Pat. No. 5,214,185 disclose the separation of DMC from a vapor mixture of methanol and DMC by using dimethyl oxalate (DMOX) as extraction solvent. Because of the high melting point of DMOX (54° C.), using DMOX is inconvenient and adds an extra cost to the separation. Both urea and alcohols are highly hygroscopic. Urea contains an ammonium carbamate impurity. Therefore, water and ammonium carbamate are impurities in urea and alcohol feed. It has been found that impurities such as water, ammonium carbamate, etc, in the urea and alcohol feeds cause catalyst deactivation and line plugging on cold spots in the cooling section (the condenser) for the overhead vapor stream from the reactor. Water causes the deactivation of catalyst containing alkyoxy groups, for example, the methoxy groups on the organotin complex compound molecules are highly reactive with water molecules resulting in hydrolysis of the bond between the tin atom and oxygen atom of methoxy group. Ammonium carbamate causes problems for controlling the backpressure in the dialkyl carbonate producing reactor and plugging the cooling system (condenser) of the product vapor stream from the dialkyl reactor, because of the deposition of ammonium carbamate. SUMMARY OF THE INVENTION Briefly the present invention is an improved process for production of dialkyl carbonate comprising the steps of: (a) feeding a stream containing urea, alcohol, water and ammonium carbamate to a first reaction zone: (b) concurrently in said first reaction zone, (i) reacting water with urea to form ammonium carbamate, (ii) decomposing the ammonium carbamate in the feed and the ammonium carbamate from the reaction of water with urea into ammonia and carbon dioxide, and (c) removing ammonia, carbon dioxide and said alcohol from said first reaction zone as a first overheads; (d) removing urea and said alcohol from said first reaction zone; (e) feeding said urea and said alcohol to a second reaction zone; (f) reacting said alcohol and urea in the presence of a homogeneous catalyst comprising an organotin complex compound of dialkylmethoxide in a high boiling solvent to form dialkyl carbonate and (g) removing dialkyl carbonate and said alcohol from said second reaction zone. Dialkyl carbonates are prepared by reacting alcohols, preferably C1-C3 alcohols, with urea or alkyl carbamate or both in the presence of a complex of organotin compound with a high boiling electron donor compound acting as a solvent, preferably dibutyltin dialkoxide complex compound and high boiling oxygen containing organic solvent, wherein the reaction is preferably carried out in the reboiler of a distillation still or a stirred tank reactor with concurrent distillation of the dialkyl carbonate. The urea and alcohol feeds are purified by removing water and ammonium carbamates, N-alkylated by-product and a minor fraction of alkylcarbamate. The water is removed by reacting it with urea in a prereactor having a preliminary reaction zone. Ammonium carbamate is removed by decomposition to ammonia and carbon dioxide in the prereactor. In addition urea is partially and selectively converted to alkyl carbamate in the prereactor which results in a faster reaction rate in the primary reactor, a reduction of alcohol recycle to the primary reactor from the dialkyl carbonate recovery unit or column and a higher concentration of dialkyl carbonate in the overhead stream from the primary reactor. A higher concentration of dialkyl carbonate in the overhead stream from the primary reactor reduces the cost of separation of the dialkyl carbonate. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified flow diagram of one embodiment for producing DMC according to the present invention. FIG. 2 is a simplified flow diagram of a DMC separation unit. FIG. 3 is a schematic representation of a one embodiment of producing DEC according to the present invention. FIG. 4 is a simplified flow diagram of a reaction/distillation column reactor embodiment for the present process. FIG. is 5 a simplified flow diagram of a catalytic stirred tank reactor with an attached distillation column embodiment for the present process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The water impurity in the urea and alcohol feeds is removed by reacting the water with urea in a prereactor while ammonium carbamate is removed by decomposing it to ammonia and carbon dioxide in the prereactor. The prereactor must be operated under favorable conditions for the decomposition such that the ammonia and carbon dioxide may be removed as vapors. If the decomposition is incomplete the unconverted ammonium carbamate will enter the primary reactor and be converted to urea and water as it decomposes to ammonia and carbon dioxide causing the deactivation of the catalyst. Urea is partially converted to alkyl carbamate in the prereactor. The following necessary reactions occur in the prereactor: Since the above four are equilibrium reactions and must occur simultaneously in the preliminary reaction zone in the prereactor, controlling the temperature and pressures of the prereactor and the primary reactor is important. The reactions (1), (2), (3) and (4) are carried out in the prereactor at a temperature from 200 to 380° F., preferably from 250 to 350° F. in liquid phase in the prereactor. The preferred range of the overhead pressure of the prereactor is from about 30 to 300 psig. However, the overhead pressure is determined mainly by the desired temperature of the prereactor column and the composition of the liquid in the reactor. Reaction (4) proceeds to equilibrium in the absence of a catalyst, but the reaction is faster in the presence of a catalyst such as dibutyltin dialkoxide complex catalyst and weakly acidic or basic heterogeneous catalyst such as zinc oxide, tin oxide, titanium oxide, zirconium oxide, molybdenum oxide, talcite, calcium carbonate, zinc carbonate hydroxide, zirconium carbonate hydroxide, etc. supported on a inert support such as silica, high temperature (>850° C.) calcined alumina. The preferred concentration of urea in the liquid phase in the preliminary reaction zone under given conditions is less than about 80 wt. %, preferably 50 wt. %. The partial pressures of ammonia and carbon dioxide must be kept below the decomposition pressure of ammonium carbamate to allow the decomposition of ammonium carbamate. It is also highly desirable to effectively remove the products, ammonia and carbon dioxide, from the preliminary reaction zone of the prereactor, preferably as a vapor mixture along with alcohol and any inert stripping gas employed as an option. Alcohol vapor may be used as the sole stripping gas if desired. Thus, the improvement is in a process for the production of dialkyl carbonates by the reaction of reactants comprising urea and alcohol having water and ammonium carbamate as impurities comprising the steps of: (a) feeding reactants comprising urea and alcohol to a primary reaction zone; (b) feeding an organotin compound and a high boiling electron donor atom containing solvent to said primary reaction zone; and (c) concurrently in said primary reaction zone (i) reacting alcohol and urea in the presence of said organotin compound and said high boiling electron donor atom containing solvent to produce dialkyl carbonate; and (ii) removing the dialkyl carbonate and ammonia from said primary reaction zone as vapor, wherein the improvement is the use of a preliminary reaction zone before the primary reaction zone to remove water, and ammonium carbamate from said reactants, by feeding the reactants, first to the preliminary reaction zone under conditions to react said water with urea to form ammonium carbamate and decompose ammonium carbamate to ammonia and carbon dioxide and removing the ammonia and carbon dioxide from said reactants prior to feeding the reactants in step (b), preferably at a temperature in the range from 200 to 380° F., more preferably from 250 to 350° F. and preferably in liquid phase. Preferably a portion of the urea and alcohol react to form alky carbamate in the preliminary reaction zone. A preferred embodiment of the process for the production of dialkyl carbonates comprises the steps of: (a) feeding urea, C1-C3 alcohol prereaction zone; (i) cleaning the impurities in feeds in the prereactor; (ii) removing ammonia, carbon dioxide and alcohol as vapor stream; (iii) reacting a portion of urea and alcohol to alkyl carbamate; and (iv) removing a liquid stream containing alkyl carbamate, urea and alcohol to introduce to a primary reaction zone; (b) feeding an organotin compound and a high boiling electron donor atom containing solvent to said primary reaction zone; (c) concurrently in said primary reaction zone (i) reacting C1-C3 alcohol, urea and alkyl carbamate in the presence of said organotin compound and said high boiling electron donor atom containing solvent to produce dialkyl carbonate; and (ii) removing the dialkyl carbonate and ammonia, ether, carbon dioxide, N-alkyl alkyl carbamate and alkyl carbamate from said primary reaction zone as vapor; and (d) converting N-alkyl alkyl carbamate separated from the vapor stream from primary reactor and in a small slipstream of liquid reaction medium from primary reaction zone to said heterocyclic compounds ((RNCO)3, where R is H or CnH2n+1 and n=1, 2 or 3) in said third clean-up reaction zone and converting alkyl carbamate to dialkyl carbonate; (i) removing heterocyclic compounds in the stream from the third reaction zone as solids; (ii) returning the reaming liquid stream to the primary reaction zone and the clean-up reaction zone, and (iii) removing ammonia, alcohol and dialkyl carbonate as overhead vapor stream This embodiment provides improvements which include the use of a preliminary reaction zone to remove water, and ammonium carbamate from said urea and alcohol, preferably at a temperature in the range from 200 to 380° F., more preferably from 250 to 350° F. and preferably in liquid phase and the use of a clean-up reaction zone to convert the by-product N-alkyl alkyl carbamate to heterocyclic compounds at a temperature in the range from 300 to 400° F. in liquid phase to remove as solid from the system. The preferred prereactor is double diameter tower reactor (wider diameter at lower section). The urea feed solution in alcohol is introduced to the column prereactor at the middle section of narrower diameter upper section. The ammonium carbamate in the urea feed is decomposed to ammonia and carbon dioxide. The temperature of the column is maintained at a temperature from about 200 to about 380° F. under from 50 to 350 psig. The light reaction products, ammonia and carbon dioxide, are removed from the column as an overhead vapor stream along with alcohol vapor. Urea in the feed stream is, at least, partially converted to alkyl carbamate in this prereactor. This reaction is exothermic. The conversion of urea is higher than 10%, preferably higher than 50%. The conversion of urea to alkyl carbamate can be carried out in the absence of the complex catalyst. But with the catalyst the conversion rate is faster. Removing water and ammonium carbamate impurities in the feed streams solves the problems associated with keeping the catalyst in the active state, controlling overhead pressure of the distillation column, and plugging of cooling area of overhead vapor stream from primary reactor by deposition of ammonium carbamate. Cleaning-up of the impurities in feeds is carried out in a prereactor, which is a double diameter distillation column reactor. Removing the impurities in the feed streams is the primary objective of the prereactor. Further improvement is made by at least partially converting urea to alkyl carbamate in the prereactor, which results in faster reaction rate of producing dialkyl carbonate in the primary reactor, a reduction of alcohol recycle to the primary reactor from dialkyl carbonate recovery unit because of higher concentration of dialkyl carbonate in the overhead stream from the primary reactor. In making dialkyl carbonate, a higher concentration of dialkyl carbonate in the overhead stream from the primary reactor reduces the separation cost of dialkyl carbonate. The primary reactor, where dialkyl carbonate is formed, is stirred tank reactor equipped with a heat exchanger to recover the latent heat of the product vapor stream from the primary reactor. The recovered heat is used to recycle alcohol from alcohol recovery column to primary reactor. It is not necessary, but optional that the liquid reaction medium is mechanically stirred. In the present invention, the reaction/distillation column of the primary reactor is operated unconventionally so that the undesired N-alkylated by-products are removed from the liquid reaction zone as parts of overhead product stream, which allows maintaining the by-products at the minimal level so that the reactor can be operated at a constant liquid level without filling the liquid reaction zone with undesired by-products for an extended period of reactor operation without any interruption. This is highly desirable for the successful commercial production of dialkyl carbonate. Lower concentrations of urea, alkyl carbamate and dialkyl carbonate in the liquid medium are utilized to minimize the rate of the formation of N-alkylated by-products, which is accomplished by using a higher concentration of high boiling solvent such as triglyme. However, if the alkyl carbamate concentration is too low an unacceptably low space yield of DMC can occur. To avoid accumulation of the by-products such as N-alkyl alkyl carbamate and heterocyclic compounds in the primary reactor, it was discovered that the N-alkyl alkyl carbamate could continuously be distilled off from the liquid reaction medium, while concurrently performing the dialkyl carbonate producing reaction, by controlling both temperature and pressure of the distillation column of the primary reactor vapor stream, and be converted to heterocyclic compounds, which can be removed as solids from the system. In other words, it was discovered that steady concentrations of N-alkyl alkyl carbamate and heterocyclic compounds in a given liquid reaction volume of the primary reaction zone could be maintained under a steady station reactor operation condition. It was also discovered that maintaining the skin temperature of any internal portion of the primary reactor at a temperature below about 550° F., preferably below 450° F. is highly desirable to minimize the formation of heterocyclic compounds in the primary reaction zone. The conversion of N-alkyl alkyl carbamate to heterocyclic compounds is carried out by employing a third clean-up reaction zone. The preferred clean-up reactor for this purpose is a stirred tank reactor equipped with an attached distillation column, a condenser and reflux drum. The by-product N-alkyl alkyl carbamate produced by alkylation of alkyl carbamate with dialkyl carbonate in the primary reaction zone is continuously removed as a part of overhead vapor stream along with other products by operating the vapor temperature from the primary reaction zone at a column temperature higher than about 255° F., preferably higher than 265° F. The N-alkyl alkyl carbamate is separated from the overhead stream from the primary reactor and introduced to the clean-up reactor. The clean-up reactor is preferably operated at a temperature of the liquid reaction medium in range from 330 to 400° F. It is important that the column temperature and the column overhead pressure are controlled so that the overhead vapor stream does not contain N-alkyl alkyl carbamate. In general, the clean-up reactor is operated at a reaction temperature and an overhead pressure at, at least, 2° F. and 5 psig higher than those of the primary reactor. The technique of removing the by-products disclosed in this invention can be extended to the prior art such as U.S. Pat. No. 6,359,163 B2 (2002) and WO 95/17369 (1995), U.S. Pat. No. 6,031,122 (2000), and EP 1167339 (2002) producing dialkyl carbonate from urea and an alcohol regardless whether a solvent is used or not in the primary reactor and the clean-up reactor. For the production of heavier alkyl carbonate such as dipropyl carbonate, dibutyl carbonate, etc., removing N-alkyl alkyl carbamate from the primary reactor as parts of the overhead stream becomes difficult. Therefore, a liquid slip stream is taken out of the primary reactor in larger quantity to the clean-up reactor. N-alkyl alkyl carbamate in this slip stream is converted to separable high boiling point materials in the clean-up reactor as disclosed in this invention. After removing high boiling waste materials in the bottom stream from the clean-up reactor, the remaining liquid stream may be returned to the primary reactor and the clean-up reactor. Various physical devices may be utilized as the prereactor. These include a distillation column reactor, a stirred tank reactor, bubble reactor, tubular reactor, boiling point reactor or any combination thereof. The preferred device is a distillation column reactor, in which the reactions are carried out under reaction/distillation conditions. Despite the equilibrium nature of the reactions (1), (2) and (3), employing the distillation column reactor allows driving the three reactions to the right, that is, complete removal of water and ammonium carbamate in the feed streams. Urea is partially converted to alkyl carbamate in the prereactor according to equilibrium reaction (4). By removing ammonia from the reaction zone as an overhead gas mixture, the reaction (4) can be forced to the right side of the reaction as well. The partial conversion of urea to alkyl carbamate increases the rate of conversion of alkyl carbamate to dialkyl carbonate in the primary reactor and results in a higher concentration of dialkyl carbonate in the overhead stream from the primary reactor because the reaction of urea with alcohol to produce dialkyl carbonate occurs in two steps and reaction (4) is the first step. The dialkyl carbonate forming reaction is as follows: Reaction (5) is carried out in the primary reactor in the presence of a high boiling solvent in the reaction/distillation mode to create a favorable condition for fast removal of dialkyl carbonate from the reaction medium as soon as it is produced. The rate of forming dialkyl carbonate in the primary reactor is more sensitive to the concentration of ammonia in reaction medium in the primary reactor than the rate of forming alkyl carbamate in the prereactor due to the chemical thermodynamics. The rate of forming dialkyl carbonate becomes faster, if, at a given concentration of alkyl carbamate, there is a lower ammonia concentration in the liquid reaction medium in the primary reactor. The temperature of the reaction medium in the primary reactor is from about 300 to about 450° F., preferably from about 320 to 400° F., most preferably from about 330 to 360° F. under a pressure from about ambient to 150 psig, preferably from 30 to 120 psig. Any combination of desired temperature and pressure, which results in high selectivity of dialkyl carbonate, can be obtainable by choosing a proper high boiling solvent and controlling the concentration of the solvent in the primary reactor. It is highly desirable that the primary reactor be operated to have the temperature of the overhead vapor at least about 300° F., preferably higher than about 320° F. for the recovery of the latent heat of the overhead vapor stream to be used for the alcohol recycle as super heated alcohol vapor to the primary reactor and prereactor. Using high boiling solvent in the primary reactor allows carrying out the reaction under low pressure and low concentration of carbamate in the liquid reaction medium. Lower pressure favors faster removal of dialkyl carbonate from the liquid reaction medium to the vapor phase, resulting in lower concentrations of dialkyl carbonate in the liquid reaction medium. The lower the concentrations of dialkyl carbonate and carbamate/urea in the liquid reaction medium, the lower the undesired by-products associated to N-alkylation and the decomposition products of urea, alkyl carbamate and N-alkylated products in the primary reactor. The preferred solvent for the synthesis of dialkyl carbonates should have the following properties: (1) The solvent should boil at least, 20° F. higher temperature than the boiling point of the dialkyl carbonate product; and (2) It should not form an azeotropic mixture with dialkyl carbonate. The examples of such a solvent are high boiling ethers, ketones, hydrocarbons, and esters or mixtures of these; triethylene glycol dimethyl ether, tetraethylene glycol dialkyl ether, anisol, dimethoxy benzene, dimethoxy toluene, alkyl oxalate, decaline, tetraline, xylene, decane, etc. or mixtures of these. A super heated alcohol vapor stream is directly introduced into the liquid reaction zone to supply the heat of reaction for the conversion of alkyl carbamate to dialkyl carbonate which is a slightly endothermic reaction, and strip off dialkyl carbonate and ammonia from the liquid reaction medium as soon as dialkyl carbonate is produced. The desired total concentration of alkyl carbamate and urea combined in the reaction medium is from about 10 to about 60 wt. %, preferably from about 15 to about 50 wt. % of the total materials in the liquid reaction medium. The desired concentration of dialkyl carbonate in the reaction medium is from about 0.5 to about 12 wt. %, preferably from about 2 to about 9 wt. % based on the total content of the liquid reaction medium. The mole ratio of alkyl carbamate to alcohol in the liquid reaction medium is from 0.2:1 to 2:1, preferably from 0.3:1 to 1.5:1. The concentration of organotin complex catalyst is from about 2 to about 20 wt. % tin, preferably from 5 to about 17 wt. % tin based on the total content of all the materials in the liquid reaction zone in the primary reactor. Note that the catalyst also catalyzes the undesired side-reactions discussed above. Carrying out the reaction at lower temperature reduces the side-reactions. However, the rate of producing dialkyl carbonate is also lower, which may not be acceptable for the commercial production of DMC. The desired concentration of high boiling solvent in the reaction medium in the primary reactor is from about 2 to about 65 wt. %, preferably from 2.5 to 55 wt. % of the total material in the reaction medium. The working catalyst under steady state reaction conditions is an organotin complex catalyst system derived from the organotin complex compound of dialkyltin dialkoxide, R′4-nSn(OR)n.xL (Where R′ is alkyl group, aryl or aralkyl group; R=alkyl; n=1 or 2; x=1 or 2; L is electron donor atom containing monodentate or bidentate liqand). The examples of L are electron donor ligand molecules such as ethers, esters, ketones, aldehydes, organic phosphines or mixtures of these; triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dimethyl oxalate, dimethyl malonate, dimethyl succinate, anisol, dimethoxy benzene, dimethoxy toluene, ethylene glycol, catecol, 1,4-dioxane-2,3-diol, 2-methyltetrahydrfuran-3-one, 2,3-pentanedione, 2,4-pentanedione, 3-methyltetrahydropyran, triphenylphosphine, etc. The homogeneous catalyst system is a quasi-equilibrium mixture of various organotin species. Suitable catalysts of this type and their method of manufacture are described in U.S. Pat. Nos. 6,010,976 and 6,392,078 which are incorporated herein in their entirety. The working catalyst system under the steady state reaction condition is a mixture of various soluble organotin monomer, dimer and oligomer species, which are produced by a number of possible reactions. These various organotin catalyst species are more or less in quasi-equilibrium state under a given reaction condition. Dialkyltin oxide, dialkyltin halides, dialkyltin bis(acetylacetonate) and dialkyltin carboxylates such as dibutyltin diacetate, dialkyltin oxalate, dibutyltin malonate, dibutyltin diacetate, dibutyltin bis(acetylacetonate) etc. can be used to form the soluble tin complex catalyst species in situ at the start-up of the primary reactor by reacting with alcohol in the presence of a high boiling solvent such as triglyme. The alkyl groups attached to tin atoms can be the same or different. For example, the catalyst precursor can be dibutyltin, butylbenzyltin, butylphenyltin, butyloctyltin or di-2-phenylethyltin dialkoxide, dihalides, hydroxyhalide, diacetate or oxide. Water, carboxylic acid or hydrochloric acid co-products are continuously removed from the liquid reaction medium as an overhead vapor stream in the presence of high boiling solvent under low pressure. The suitable temperature for the catalyst forming reaction is from about 200 to about 400° F. and pressure from about ambient to 150 psig. In a preferred embodiment, methanol, ethanol or propanol depending on the intended dialkyl carbonate product is continuously pumped into the primary reactor. Either methanol or ethanol is acceptable for the production of MEC. The catalyst forming reaction is advantageously carried out in the presence of dilute alkyl carbamate, N-alkyl alkyl carbamate or dialkyl solution in the primary reactor. It is understood that during this catalyst forming reaction the operation of the distillation column should be operated under conditions, which allow removing co-products water, carboxylic acid or hydrogen chloride as an overhead stream along with alcohol as an overhead product from the reaction zone. For the dimethyl carbonate production, the soluble organotin complex catalyst system is formed by simply mixing dibutyltin dimethoxide with triglyme (as a complex agent for the formation of organotin complex catalyst) and methanol in the primary reactor prior to initiating the dialkyl carbonate forming reaction in the presence of a high boiling solvent. For diethyl carbonate production, the soluble organotin complex catalyst system is preferably formed by using dibutyltin dimethoxide with triglyme and ethanol in a primary reactor. As the reaction proceeds, the methoxy groups on the catalyst are replaced with ethoxy groups. Referring now to FIG. 1 there is shown a simplified flow diagram of one embodiment of the invention. FIG. 1 illustrates the flow diagram of the improved process excluding the DMC separation unit. The DMC separation unit is illustrated in FIG. 2. A reaction/distillation column reactor 111 is used as the prereactor to remove the impurities in the feed streams and for the partial conversion of urea to methyl carbamate. Urea solution is prepared in the drum 131 by mixing urea feed 1 and methanol stream 3. The methanol stream is comprised of the fresh methanol feed stream 2 and a methanol recycle stream 4, which is a portion of the methanol recycle stream 30 from the DMC separation unit. The methanol recycle stream 30 from the DMC separation unit (shown in FIG. 2) splits into three streams (4 and 33 via 31, and 32) to be used for the preparation of urea solution, the primary reactor 112 and the clean-up reactor 113. The urea solution feed 5 from the drum 131 is introduced to the middle of upper narrower column section of the double diameter tower reactor 111. The reactor 111 serves as a prereactor to clean up the impurities (water and ammonium carbamate) in the methanol and urea feeds, and to partially covert urea to MC. A vapor stream 6 from the prereactor 111 is composed of ammonia, carbon dioxide and methanol. The cleaned mixed solution of MC and urea in methanol is removed from the prereactor 111 as bottom stream 7 and combined with the recycle liquid stream 22 from the cooling/filter system 133 via the line 20 to the stream 8. Liquid recycle stream 20 from the cooling/filter system 133 splits into two streams (21 and 22) to recycle to primary reactor 112 and clean-up reactor 113. The combined stream 8 is introduced to the primary reactor (stirred tank reactor or optionally bubble column reactor) 112. The recycle methanol stream 33 from the DMC separation unit is introduced into the primary reactor 112 as super heated methanol vapor. The overhead recycle stream 14 from the flash column 132 is introduced to the primary reactor. The stream 14 is comprised of mostly MC and minor amounts of N-MMC and methanol. The overhead vapor stream 9 from the primary reactor 112 is comprised of ammonia, CO2, dimethyl ether, methanol, DMC, MC, N-MMC, TG and a small amount of organotin catalyst. This overhead stream 9 from the primary reactor 112 is combined with the overhead stream 17 from the clean-up stirred tank reactor 113 to the stream 10. The stream 17 is comprised of ammonia, CO2, dimethyl ether, methanol and DMC. The combined stream 10 is introduced to the distillation column 151 to separate the components, ammonia, CO2, dimethyl ether, methanol and DMC from the rest of heavier components in the stream. Overhead stream 12 from the column 151 is combined with the overhead stream 6 from the prereactor reactor 111 to the stream 23. The combined stream 23 is introduced to the distillation column 134. Overhead stream 25 from the column 134 is sent to the ammonium carbamate removing system 135, where the stream 25 is suitably cooled to cause the reaction of CO2 and ammonia to ammonium carbamate and precipitation of solid ammonium carbamate. Solid ammonium carbamate may be removed by using a filter or hydroclone. Stream 27 from the ammonium carbamate removing system 135 is introduced to the distillation column 136 to recover ammonia. Overhead stream 28 from the column 136 is sent to an ammonia storage tank. Bottom stream 29 from the column 136 is organic waste, mostly composed of dimethyl ether. Bottom stream 24 from the column 134 is sent to the DMC separation unit shown in FIG. 2. Stream 24 is comprised of DMC and methanol. Bottom stream 13 from the column 151 is sent to the flash column 132. Stream 13 is comprised of methanol, MC, N-MMC, TG and a small amount of catalyst. Bottom stream 15 from the flash column 132 is comprised of N-MMC, MC (minor amount), TG and a small amount of organotin catalyst. Stream 15 is combined with a small liquid slipstream 11 from the primary reactor 112 to the stream 16. The combined stream 16 is introduced to the clean-up reactor 113 (Optionally the small slipstream 11 from the primary reactor 112 may be introduced to the lower section of either the column 151 or 132). Bottom stream 18 from the clean-up reactor 113 is chilled to precipitate the heterocyclic compounds such as isocyanuric acid, 1,3,5-trimethyl triazine-2,4,6-trione, etc. in the stream and the precipitate is removed from the filtration system 133 as solid through line 19. Liquid filtrate stream 20 from the filtration system 133 splits to two streams 21 and 22 to recycle back to primary reactor 112 and clean-up reactor 113. The primary reactor can be a single stirred tank reactor or a multiple stirred tank reactor system depending on the production capacity of dialkyl carbonate. For example, if the primary reactor is comprised of a series of three stirred tank reactors, the cleaned alkyl carbamate/urea feed stream 7 from the prereactor 111 is suitably divided into three streams and each stream is introduced directly to three reactors. A liquid reaction stream is withdrawn from each reactor and introduced to the next reactor. The liquid reaction stream from the third reactor is sent to the first reactor. A small slipstream from the liquid reaction stream from the third reactor is combined with the bottom stream 15 from column 132 to stream 16, which is sent to clean-up reactor 113. The alcohol recycle stream such as methanol recycle stream 33 from the DMC separation unit is introduced to the first reactor as super heated alcohol vapor. The overhead vapor stream from the first stirred tank reactor is introduced to the second reactor. The overhead vapor stream from the second reactor is introduced to the third reactor. The content of dialkyl carbonate in the overhead stream from each reactor increases as the vapor stream moves from the first reactor to third reactor, resulting in the highest concentration of DMC in the overhead stream from the third reactor. Overhead stream 9 from the third reactor is combined with the overhead stream 17 from clean-up reactor 113 to stream 10, which is introduced to the distillation column 151. Bottom stream 24 from distillation column 134 is sent to the DMC separation unit (see FIG. 2). This stream contains about 28 wt. % DMC. Stream 24 from column 134 is introduced into the extractive distillation column 137 through line 34. Overhead stream 35, which is comprised of about 98 wt. % methanol and about 2 wt. % DMC, is recycled through line 30 in FIG. 1. Bottom stream 36 is introduced into extractive solvent recovery column 138. The extractive solvent, anisole, is recovered as bottom stream 38 from column 138 and recycled back to column 137 through line 38. Overhead stream 37 from column 138 is the product DMC, which is sent to a DMC storage tank. Diethyl carbonate (DEC) can be produced in a similar manner described above for the production of DMC. Since the mixture of ethanol and DEC does not form an azeotrope, the separation of DEC from ethanol can be carried out with a single distillation column. FIG. 3 illustrates the simplified flow diagram of the process for the production of DEC. The urea solution is prepared in drum 141 by mixing urea feed 101 and ethanol stream 103. Ethanol stream 103 is comprised of fresh ethanol feed 102 and ethanol recycle stream 155, which is a portion of ethanol recycle stream 130. Ethanol recycle stream 130 is comprised of overhead stream 117 from distillation column 146 and bottom stream 129 from distillation column 145 (ethanol recovery column). Ethanol recycle stream 130 splits into two streams 152 and 156. Stream 152 is recycled to clean-up reactor 123. Stream 156 splits again to two streams 155 and 157 to recycle to drum 141 and primary reactor 122, respectively. Ethanol recycle stream 157 is introduced to primary reactor 122. The urea solution 104 from drum 141 is introduced to the middle of upper narrower column section of the double diameter tower reactor 121. Reactor 121 serves as a prereactor to clean up the impurities (water and ammonium carbamate) in the feeds, ethanol and urea, and to partially convert urea to EC. Vapor stream 105 from prereactor 121 is composed of ammonia, carbon dioxide and ethanol. The cleaned mixed solution is removed from prereactor 121 as bottom stream 106. Stream 106 is introduced to primary reactor (stirred tank reactor or optionally bubble column reactor) 122. Recycle ethanol stream 157 (this stream is the major portion of the ethanol recycle stream 130) is introduced into the primary reactor 122 as superheated ethanol vapor. A small slipstream 108 from primary reactor 122 is combined with bottom stream 120 from DEC recovery column 147 to form stream 161 and combined stream 161 is introduced to clean-up reactor 123. Slipstream 108 is composed of ethanol, ammonia, diethyl ether, DEC, ethyl carbamate, N-ethyl ethyl carbamate, TG, heterocyclic compounds such as isocyanuric acid, 1,3,5-triethyl triazine-2,4,6-trione, etc and organotin complex catalyst. Stream 120 is comprised of ethanol, ethyl carbamate, N-ethyl carbamate, TG, and trace amounts of catalyst. Overhead stream 160 from clean-up reactor 123 is comprised of ammonia, CO2, diethyl ether, ethanol, and DEC. Bottom stream 159 from the clean-up reactor 123 is comprised of ethyl carbamate, triglyme, N-ethyl ethyl carbamate, ethanol, heterocyclic compounds and homogeneous organotin catalyst. Bottom stream 159 from reactor 123 is cooled to precipitate heterocyclic compounds in the cooling/filter system 148. The precipitate solid by-product is removed from system 148 through line 124. Liquid stream 125 from system 148 splits into two streams 126 and 127 to recycle to primary reactor 122 and clean-up reactor 123. Overhead stream 107 from primary reactor 122 is combined with overhead stream 160 from clean-up reactor 123 to stream 109. Overhead vapor stream 107 from primary reactor 122 is composed of ammonia, CO2, diethyl ether, ethanol, ethyl carbamate, N-ethyl ethyl carbamate, DEC, TG and trace amount of catalyst. Stream 107 is combined with overhead stream 160 from clean-up reactor 123 to stream 109. Overhead stream 160 is comprised of ammonia, CO2, diethyl ether, ethanol and DEC. Combined stream 109 is introduced to distillation column 142. Overhead stream 110 from column 142, which is composed of ammonia, CO2, diethyl ether and ethanol, is introduced to distillation column 143. Overhead stream 154 from column 143 is cooled to cause the reaction of CO2 with ammonia to produce ammonium carbamate. Ammonium carbamate is precipitate in liquid ammonia and removed as solids through line 115 from cooling/filter system 144. Liquid ammonia stream 116 from cooling/filter system 144 is sent to an ammonia storage tank. Bottom stream 150 from column 142 is composed of DEC, ethanol, ethyl carbamate, N-ethyl ethyl carbamate, TG and a trace amount of catalyst. Stream 150 is introduced to distillation column 146 (the first ethanol recovery column). Overhead ethanol stream 117 from column 146 is combined with ethanol bottom stream 129 from distillation column 145 (the second ethanol recovery column) to ethanol recycle stream 130. Bottom stream 118 from column 146 is introduced to distillation column 147 (DEC recovery column). Overhead stream 119 is the product DEC, which is sent to a DEC storage tank. Bottom stream 120 from column 147 is combined with a small slipstream 108 from primary reactor 122 and combined stream 161 is introduced to stirred tank clean-up reactor 123. Overhead stream 160, which is composed of ammonia, CO2, diethyl ether, ethanol and DEC, is sent to column 142 through line 109. Bottom stream 114 from column 143 is sent to distillation column 145 to separate diethyl ether from ethanol in the stream. The overhead ether by-product stream 128 is sent to an ether storage tank. Bottom stream 129 from column 145 is ethanol, which is recycled to clean-up reactor 123 and primary reactor 122 through line 130. A mixed dialkyl carbonate such as methyl ethyl carbonate (MEC) is produced by using suitable mixtures of methanol and ethanol as feed streams in place of the methanol or ethanol feed stream to the drum for the preparation of urea solution. However, the overhead streams from the primary and clean-up reactors contain some DMC and DEC in addition to MEC. DEC and DMC are separated from the mixture and the exchange reaction of DEC and DMC to MEC is carried out in a separate reactor (not shown). This exchange reaction is carried out by using either a heterogeneous base catalyst such as an alkaline form of zeolites, basic talcite, etc or a homogeneous catalyst such as Group IVB compounds such as titanium tetraethoxide or ethoxycarbonates or dialkyltin compounds such as alkoxide, dialkyltin methoxy alkyl carbonate, dialkyltin carbonate, or the organotin complex catalyst system discussed above in the absence or presence of a solvent. The suitable solvent will have a boiling point higher than about 265° F. The examples of such a solvent are hydrocarbons such as decaline, decane, xylene, diglyme, triglyme, etc or mixtures of these. FIG. 4 illustrates a reaction/distillation column reactor using a basic heterogeneous catalyst. The DEC feed is introduced to the reaction/distillation column reactor 153 through lines 221 at a position of the top section of catalyst bed. The DMC feed is introduced to 153 at a position below the catalyst bed through line 222. The overhead stream 223 is comprised of mostly DMC and MEC. The stream 223 is sent to MEC separation unit. The temperature of the liquid catalytic reaction zone is maintained in a range from about 200 to about 450° F., preferably from 235 to 380° F. To prevent the build-up of heavies in the reboiler of column reactor 153, a small amount of bottom is withdrawn through line 224. FIG. 5 illustrates a catalytic stirred tank reactor 158 with an attached distillation column 162. A homogeneous catalyst such as dibutyltin dimethoxide is used. A predetermined amount of a homogeneous catalyst is charged into reactor 158 prior to carrying out the reaction. A mixed DEC/DMC feed is introduced to reactor 158 through line 301. The overhead stream 303 from 162 is comprised of mostly DMC and a small amount of MEC is recycled back to reactor 158. A side draw stream 302, which is concentrated with MEC, from distillation column 162 is sent to distillation column 163 to separate MEC from DMC. The overhead stream 304 from column 163 is recycled back to reactor 158. The bottom MEC stream 305 from column 163 is sent to a MEC storage tank. The temperature of the liquid catalytic reaction zone is maintained in a range from about 200 to about 450° F., preferably from 235 to 380° F. The range of the overhead pressure of column 162 is from about 20 psig to about 150 psig, preferably from about 25 to about 120 psig. But the overhead pressure of column 162 is determined by the intended temperature of liquid reaction medium in 158, the composition of the reaction medium, and whether a solvent is used or not. EXAMPLE 1 The reaction of water with urea is carried out in this example. The following materials are charged in a 500 ml three neck flask equipped with a magnetic stirrer and water cooled reflux condenser: 229.67 grams triethylene glycol dimethyl ether (triglyme), 1.58 grams of water, 2.06 grams of methanol and 15.89 grams of urea. When the reaction temperature of the mixture in the flask reaches about 100° C., 3.2 grams of additional methanol are added. The reaction of water with urea is carried out at a temperature from 128 to 140° C. for 0.92 hours under nitrogen blanket. The analysis of the sample taken from the flask are carried out by GC and HPLC. The analytical results indicate 22.4% conversion of urea and 45.2% conversion of water. EXAMPLE 2 General Description of the Experiment A one liter stirred autoclave serves as the reaction zone and reboiler for the reaction/distillation column reactor, which is connected to a 1 inch diameter×3.5 feet long distillation column. The distillation column has three zone heaters, which are independently controlled. The overhead vapor stream from the distillation column is diluted with a nitrogen stream (800 cc/min) and then partially cooled to about 200° F. with hot water in a condenser. The vapor stream from the condenser cooled to ambient temperature to prevent the plugging problem of a cold spot and overhead backpressure regulator. The liquid stream from the condenser flows to a small overhead liquid reflux drum. The temperature of the liquid reflux drum is maintained at ambient temperature. The flow of the liquid product from the overhead reflux drum is monitored with a LFM (liquid flow meter). The liquid stream from the overhead reflux drum and the cooled vapor stream are combined as product stream from the reaction/distillation reactor. Samples are taken for analyses to determine the composition of the overhead vapor stream coming out of the column. Also occasionally samples are taken from the reboiler to monitor the composition of the liquid reaction medium. Whenever the samples are taken from the reboiler, the make-up solutions are pumped in to compensate for the loss of triglyme and catalyst. During the operation of the reactor, the liquid level inside the reboiler is maintained at a constant level. A vertical sight glass is attached to the reboiler for the visual observation of the liquid level inside the reboiler during the operation. Also the reboiler is equipped with a liquid level digital monitor for the automatic control of the reactor during the night and weekends for unattended operation. To carry out the operation of the primary reactor to produce DMC, a MC feed solution (methyl carbamate in methanol) and a methanol feed are pumped in and combined into a single stream. The combined feed stream is passed through a prereactor (a vertically mounted tubular reactor up-flow) at 300° F. and 230 psig to remove water in the feed streams and then introduced to the primary reactor. The temperature of the liquid reaction medium is controlled by adjusting the overhead pressure of the distillation column and the concentration of high boiling solvent in the reboiler of the distillation column. The products DMC, ammonia and other light by-products such as dimethyl ether and CO2 are boiled off from the liquid medium and carried away along with methanol vapor. The operation of the distillation column is carried out in the unconventional mode to perform partial condensation of the vapor coming out of the liquid medium in the reboiler without liquid reflux from the overhead reflux drum by controlling the vapor temperature, which is done by controlling the zone temperatures of the column with three column zone heaters, while the vapor is coming up the distillation column. It was discovered that the unconventional column operation keeps the triglyme solvent in the reactor and continuously removes the by-product N-MMC along with MC from the liquid reaction medium as a part of the overhead stream, which allows the operation of the reactor for an extended period of time. It is found that no liquid reflux from the overhead reflux drum is highly preferred in minimizing the formation of the by-product N-MMC and heterocyclic compounds. It was possible to operate the reaction/distillation column reactor more than 1000 hours without interruption until a high pressure nitrogen valve to the reboiler was accidentally opened. Operating the distillation column in the conventional way causes shutdown or removal of materials from the reboiler, because of the overflow of the reboiler due to the accumulation of the reaction by-products such as N-MMC, cyanuric acid and TTT (1,3,5-trimethyl triazine-2,4,6-trione), etc. Other critical factors to minimize the side-reactions while maintaining an acceptable DMC production rate are balancing the concentrations of solvent and catalyst, the temperature of liquid medium and the overhead column pressure. The range of optimum operation for the reboiler temperature and the overhead column pressure is from about 330 to about 355° F. for the reboiler temperature and from about 80 to about 110 psig respectively. Detailed Description of the Experiment The reboiler of the distillation column was loaded with the following materials; 285 grams of triglyme, 100 grams of methanol and 100 grams of dibutyltin dimethoxide. A steady state operation of the reaction/distillation column reactor was obtained, while pumping in the 13.3 wt. % MC solution in methanol (˜280 ppm H2O) at a fixed rate of 3.01 ml/min and about 1.92 ml/min of methanol (˜80 ppm H2O) at 345° F. for the liquid reaction medium in the reboiler, 260° F. for the vapor temperature in the top section of the distillation column, and 90.8 psig for the overhead column pressure. The flow rate of methanol was adjusted to maintain a constant temperature of 345° F. for the liquid reaction medium. The stirring rate of the reboiler was 300 rpm. Under this operational condition, the overhead product stream was composed of ammonia, dimethyl ether, carbon dioxide, DMC, MC, NMMC, water, unknowns and a trace amount (˜1000 ppb) of catalyst. At 926 hours on stream time, the overheads and the bottoms samples were taken. The analyses of these samples are listed in Table 1. The mole ratio of MC/CH3OH and DMC wt. % based on MC and CH3OH in the liquid medium in the reactor are 1.01 and 4.49 wt. % respectively, which interestingly compare with 2-10 and 1-3 wt. % claimed in U.S. Pat. No. 5,561,094 (1996, EXXON Chem). The result of the experiment corresponds to better than 95 mole % of MC to DMC. This experimental data is used to carry out computer simulation for the process design. TABLE 1 Sample Analysis (wt. %) OVHD BTM CO2 0.10 0.04 NH3 0.73 0.00 (CH3)2O 0.04 0.00 Methanol 90.45 11.02 DMC 8.15 1.67 MC 0.36 26.17 N-MMC 0.17 1.88 TG 0.00 40.89 Unknown 0.01 0.31 TTT 0.00 3.66 Water (ppm) 87 — Sn (ppm) ˜1 14.35* *as dibutyltin dimethoxide EXAMPLE 3 A one liter stirred reactor (autoclave) with a distillation column was used to remove impurities in an 8.03 wt. % urea solution in methanol and convert urea to methyl carbamate. No catalyst was charged to the reactor. The experiment was carried out at 315° F. under 200 psig and 328° F. under 230 psig by pumping in the urea solution into the reactor at 4 ml/min with the constant bottom flow rate at 2 ml/min for 27 hours and 3 ml/min with the constant bottom flow rate at 1.5 ml/min to the end (146 hours on stream time) of the run. The distillation column is operated with overhead reflux. During the operation, the overhead flow was adjusted to maintain a constant liquid level (50% full) in the autoclave. The column operation was done with overhead reflux from the overhead reflux drum. The MC concentration in the bottom stream from the autoclave was about 20% on average, which corresponds to about 97% conversion of urea to MC. The urea feed contained about 2000 ppm water. The bottom products contained 375 ppm water at 315° F. and 300 ppm water at 328° F. on average. EXAMPLE 4 The purpose of this experiment is demonstrating a primary reactor system, which is composed of multiple reactors. The same experimental set-up in Example 2 was used to demonstrate the performance of the second primary reactor. The experiment was carried out in the similar manner to the Experiment 2. The present example differs from the Example 2 in that the 8 wt. % DMC solution in methanol is used herein in the place of pure methanol in the Experiment 2 and a slightly lower overhead pressure (88 psig) in the present distillation column. The reboiler of the distillation column was loaded with the following materials; 285 grams of triglyme, 40 grams of methanol and 100 grams of dibutyltin dimethoxide. A steady state operation of the distillation column reactor was obtained, while pumping in MC solution and DMC-methanol solution to the reactor. The reactor operation was continued for more than 1500 hours without interruption at 345° F. for the liquid reaction medium in the reboiler, the distillation column temperature of ˜278° F., and 88 psig for the overhead column pressure. The average compositions of the overhead and bottom products from the reactor during the 54 hours from 1428 hours to 1482 hours of on-stream-time are listed in Table 2. During this period, the pumping rate of a 22.5 wt. % MC solution (˜590 ppm H2O) was fixed at 1.97 ml/min and the pumping rate of a 8 wt. % DMC solution (80 ppm H2O) was about 3.2 ml/min at 345° F. The mole ratio of MC/CH3OH and DMC wt. % based on MC and CH3OH in the liquid medium in the reactor are 0.915 and 6.40 wt. % respectively. The result of the experiment corresponds to better than 93 mole % of MC to DMC. TABLE 2 Sample Analysis (wt. %) OVHD BTM CO2 tr — NH3 0.89 — (CH3)2O 0.06 — Methanol 84.91 13.32 DMC 12.35 2.68 MC 1.41 28.58 N-MMC 0.36 2.28 TG 0 36.55 HC* 0 3.77 Catalyst** 12.83 Water (ppm) 39 — Sn (ppm) 0.6 — *HC; isocyanic acid and 1,3,5-trimethyl triazine-2,4,6-trione **as dibutyltin dimethoxide EXAMPLE 5 The purpose of this experiment is demonstrating the production of diethyl carbonate (DEC). DEC was produced by reacting ethyl carbamate (EC) with ethanol. The experiment was carried out in the similar manner to the Example 2. An ethyl carbamate solution in ethanol and ethanol were used in place of MC solution and methanol respectively in Example 2. The reboiler of the distillation column was loaded with the following materials; 180 grams of triglyme, 100 grams of ethanol and 100 grams of dibutyltin dimethoxide. A steady state operation of the distillation column reactor was obtained, while pumping in an ethyl carbamate (EC) solution at a constant flow rate and adjusting the ethanol pumping rate to maintain a constant temperature of the liquid reaction medium. The reactor operation was continued for 340 hours without interruption at ˜345° F. of the liquid reaction medium in the reboiler, the distillation column temperature of ˜282° F., and a constant overhead pressure of 66 psig with an autoclave stirring rate of 300 rpm. The pumping rate of a 15.35 wt. % EC solution (˜275 ppm H2O) was fixed at 2.69 ml/min and the average pumping rate of ethanol (˜106 ppm H2O) was 2.36 ml/min. The overhead vapor stream at the top of the column was mixed with nitrogen dilution gas (600 cc/min) and then cooled to about 200° F. in a water cooled condenser. The average compositions of the overhead products and the composition of the bottom products for the entire run are listed in Table 3. 74.2 grams of solid material were removed from the reactor at the end run, which was a mixture of heterocyclic compounds and contained 670 ppm Sn by weight. The analysis of the bottom product in Table 3 indicates that the mole ratio of EC/C2H5OH and DEC wt. % based on EC and ethanol in the liquid medium in the reactor was 0.939 and 11.08 wt. % respectively. The mass balance and urea mole balance for the entire run were 102% and 101%, respectively. The run result indicates 57.5% conversion of EC and 91 mole % selectivity of EC to DEC. The experimental result translates to DEC space yield of 1.60 lb/h/ft3. TABLE 3 Sample Analysis (wt. %) OVHD BTM CO2 tr — NH3 0.50 — Ether 0.02 0.11 Ethanol 90.21 17.60 DEC 7.30 5.50 EC 1.74 32.00 N-EEC 0.15 1.75 TG 0.04 21.05 Unknown 0.04 9.34 HC* 0.00 0.95 Catalyst** — 11.70 Water (ppm) 148 — Sn (ppm) 1.7 — *HC; isoycanic acid and 1,3,5-triethyl triazine-2,4,6-trione **as dibutyltin dimethoxide | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a process for the production of dialkyl carbonates, particularly C 1 -C 3 dialkyl carbonates wherein the reaction occurs simultaneously with separation of the reactants and the carbonate products. More particularly the invention relates to a process wherein alcohol is reacted with urea and/or alkyl carbamate in the presence of a complex compound catalyst. More particularly the invention relates to a process wherein feed stream impurities are removed to produce stable catalyst performance, improved reaction rates and trouble free downstream operation of equipment. 2. Related Art Dialkyl carbonates are important commercial compounds, the most important of which is dimethyl carbonate (DMC). Dimethyl carbonate is used as a methylating and carbonylating agent and as a raw material for making polycarbonates. It can also be used as a solvent to replace halogenated solvents such as chlorobenzene. Although the current price of both dimethyl carbonate and diethyl carbonate is prohibitively expensive to use as fuel additive, both could be used as an oxygenate in reformulated gasoline and an octane component. Dimethyl carbonate has a much higher oxygen content (53%) than MTBE (methyl tertiary butyl ether) or TAME (tertiary amyl methyl ether), and hence not nearly as much is needed to have the same effect. It has a RON of 130 and is less volatile than either MTBE or TAME. It has a pleasant odor and, unlike ethers, is more readily biodegradable. In older commercial processes dimethyl carbonate was produced from methanol and phosgene. Because of the extreme toxicity and cost of phosgene, there have been efforts to develop better, non-phosgene based processes. In one new commercial process, dimethyl carbonate is produced from methanol, carbon monoxide, molecular oxygen and cuprous chloride via oxidative carbonylation in a two-step slurry process. Such a process is disclosed in EP 0 460 735 A2. The major shortcomings of the process are the low production rate, high cost for the separation of products and reactants, formation of by-products, high recycle requirements and the need for corrosion resistant reactors and process lines. Another new process is disclosed in EP 0 742 198 A2 and EP 0 505 374 B1 wherein dimethyl carbonate is produced through formation of methyl nitrite instead of the cupric methoxychloride noted above. The by-products are nitrogen oxides, carbon dioxide, methylformate, etc. Dimethyl carbonate in the product stream from the reactor is separated by solvent extractive distillation using dimethyl oxalate as the solvent to break the azeotropic mixture. Although the chemistry looks simple and the production rate is improved, the process is very complicated because of the separation of a number of the materials, balancing materials in various flow sections of the process, complicated process control and dealing with methyl nitrite, a hazardous chemical. In another commercial process dimethyl carbonate is produced from methanol and carbon dioxide in a two-step process. In the first step cyclic carbonates are produced by reacting epoxides with carbon dioxide as disclosed in U.S. Pat. Nos. 4,786,741; 4,851,555 and 4,400,559. In the second step dimethyl carbonate is produced along with glycol by exchange reaction of cyclic carbonates with methanol. See for example Y. Okada, et al “Dimethyl Carbonate Production for Fuel Additives”, ACS, Div. Fuel Chem., Preprint, 41(3), 868, 1996, and John F. Knifton, et al, “Ethylene Glycol-Dimethyl Carbonate Cogeneration”, Journal of Molecular Chemistry , vol. 67, pp 389-399, 1991. While the process has its advantages, the reaction rate of epoxides with carbon dioxide is slow and requires high pressure. In addition, the exchange reaction of the cyclic carbonate with methanol is limited by equilibrium and methanol and dimethyl carbonate form an azeotrope making separation difficult. It has been known that dialkyl carbonates can be prepared by reacting primary aliphatic alcohols such as methanol with urea (1) in the presence of various heterogeneous and homogeneous catalysts such as dibutyltin dimethoxide, tetraphenyltin, etc. See for example P. Ball et al, “Synthesis of Carbonates and Polycarbonates by Reaction of Urea with Hydroxy Compounds”, C 1 Mol. Chem ., vol. 1, pp 95-108, 1984. Ammonia is a coproduct and it may be recycled to urea (2) as in the following reaction sequence. Carbamates are produced at a lower temperature followed by production of dialkyl carbonates at higher temperature with ammonia being produced in both steps. As noted the above two reactions are reversible under reaction conditions. The order of catalytic activity of organotin compounds is R 4 Sn<R 3 SnX<<R 2 SnX 2 , wherein X=Cl, RO, RCOO, RCOS. A maximum reaction rate and minimum formation of by-products are reported for dialkyl tin (IV) compounds. For most catalysts (Lewis acids), higher catalyst activity is claimed if the reaction is carried out in the presence of an appropriate cocatalyst (Lewis base). For example, the preferred cocatalyst for organic tin (IV) catalysts such as dibutyltin dimethoxide, dibutyltin oxide, etc. are triphenylphosphine and 4-dimethylaminopyridine. However, thermal decomposition of intermediate alkyl carbamates and urea to isocyanic acid (HNCO) or isocyanuric acid ((HNCO) 3 ) and alcohol or ammonia (a coproduct of urea decomposition) is also facilitated by the organotin compounds such as dibutyltin dimethoxide or dibutyltin oxide employed in the synthesis of dialkyl carbamates. WO 95/17369 discloses a process for producing dialkyl carbonate such as dimethyl carbonate in two steps from alcohols and urea, utilizing the chemistry and catalysts published by P. Ball et al. In the first step, alcohol is reacted with urea to produce an alkyl carbamate. In the second step, dialkyl carbonate is produced by reacting further the alkyl carbamate with alcohol at temperatures higher than the first step. The reactions are carried out by employing an autoclave reactor. However, when methanol is reacted with methyl carbamate or urea, N-alkyl by-products such as N-methyl methyl carbamate (N-MMC) and N-alkyl urea are also produced according to the following reactions: The dialkyl carbonate is present in the reactor in an amount between 1 and 3 weight % based on total carbamate and alcohol content of the reactor solution to minimize the formation of the by-products. In U.S. Pat. No. 6,010,976, dimethyl carbonate (DMC) is synthesized from urea and methanol in high yield in a single step in the presence of high boiling ethers and a novel homogeneous tin complex catalyst. in-line-formulae description="In-line Formulae" end="lead"? (NH 2 ) 2 CO+2CH 3 OH=====>(CH 3 O) 2 CO+2NH 3 in-line-formulae description="In-line Formulae" end="tail"? The ether solvent also serves as complexing agent to form the homogenous complex catalyst from dibutyltin dimethoxide or oxide in situ. The separation of materials involved in the DMC processes is very important for the commercial production of DMC for economic reasons. EP 0 742 198 AI and U.S. Pat. No. 5,214,185 disclose the separation of DMC from a vapor mixture of methanol and DMC by using dimethyl oxalate (DMOX) as extraction solvent. Because of the high melting point of DMOX (54° C.), using DMOX is inconvenient and adds an extra cost to the separation. Both urea and alcohols are highly hygroscopic. Urea contains an ammonium carbamate impurity. Therefore, water and ammonium carbamate are impurities in urea and alcohol feed. It has been found that impurities such as water, ammonium carbamate, etc, in the urea and alcohol feeds cause catalyst deactivation and line plugging on cold spots in the cooling section (the condenser) for the overhead vapor stream from the reactor. Water causes the deactivation of catalyst containing alkyoxy groups, for example, the methoxy groups on the organotin complex compound molecules are highly reactive with water molecules resulting in hydrolysis of the bond between the tin atom and oxygen atom of methoxy group. Ammonium carbamate causes problems for controlling the backpressure in the dialkyl carbonate producing reactor and plugging the cooling system (condenser) of the product vapor stream from the dialkyl reactor, because of the deposition of ammonium carbamate. | <SOH> SUMMARY OF THE INVENTION <EOH>Briefly the present invention is an improved process for production of dialkyl carbonate comprising the steps of: (a) feeding a stream containing urea, alcohol, water and ammonium carbamate to a first reaction zone: (b) concurrently in said first reaction zone, (i) reacting water with urea to form ammonium carbamate, (ii) decomposing the ammonium carbamate in the feed and the ammonium carbamate from the reaction of water with urea into ammonia and carbon dioxide, and (c) removing ammonia, carbon dioxide and said alcohol from said first reaction zone as a first overheads; (d) removing urea and said alcohol from said first reaction zone; (e) feeding said urea and said alcohol to a second reaction zone; (f) reacting said alcohol and urea in the presence of a homogeneous catalyst comprising an organotin complex compound of dialkylmethoxide in a high boiling solvent to form dialkyl carbonate and (g) removing dialkyl carbonate and said alcohol from said second reaction zone. Dialkyl carbonates are prepared by reacting alcohols, preferably C 1 -C 3 alcohols, with urea or alkyl carbamate or both in the presence of a complex of organotin compound with a high boiling electron donor compound acting as a solvent, preferably dibutyltin dialkoxide complex compound and high boiling oxygen containing organic solvent, wherein the reaction is preferably carried out in the reboiler of a distillation still or a stirred tank reactor with concurrent distillation of the dialkyl carbonate. The urea and alcohol feeds are purified by removing water and ammonium carbamates, N-alkylated by-product and a minor fraction of alkylcarbamate. The water is removed by reacting it with urea in a prereactor having a preliminary reaction zone. Ammonium carbamate is removed by decomposition to ammonia and carbon dioxide in the prereactor. In addition urea is partially and selectively converted to alkyl carbamate in the prereactor which results in a faster reaction rate in the primary reactor, a reduction of alcohol recycle to the primary reactor from the dialkyl carbonate recovery unit or column and a higher concentration of dialkyl carbonate in the overhead stream from the primary reactor. A higher concentration of dialkyl carbonate in the overhead stream from the primary reactor reduces the cost of separation of the dialkyl carbonate. | 20040408 | 20060711 | 20050915 | 90730.0 | 0 | CHU, YONG LIANG | PROCESS FOR MAKING DIALKYL CARBONATES | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,821,334 | ACCEPTED | Sleeping bag with vented footbox | A vented sleeping bag comprising an elongate shell defining an inner volume sized and shaped to receive a user therein. The shell has a head end, a foot end, left and right sides extending longitudinally of the shell, an overlying portion which overlies the user, and an underlying portion which underlies the user. The overlying portion of the shell has at least one vent. A closure is selectively movable between a closed position for closing the vent and an open position for creating a vent opening for ventilating the inner volume of the shell. | 1. A vented sleeping bag comprising: an elongate shell defining an inner volume sized and shaped to receive a user therein, the elongate shell having a head end, a foot end, left and right sides extending longitudinally of the shell, an overlying portion adapted to overlie said user and an underlying portion adapted to underlie said user; at least one vent in said overlying portion of the shell located adjacent the foot end of the shell between the left and right sides of the shell; and a closure selectively movable between a closed position for closing said at least one vent and an open position for creating a vent opening for ventilating the inner volume of the shell. 2. The sleeping bag as set forth in claim 1 wherein the at least one vent extends longitudinally of the shell. 3. The sleeping bag as set forth in claim 2 wherein the at least one vent extends longitudinally from generally about the foot end of the shell toward the head end of the shell a distance corresponding to about 10 to 50 percent of the overall length of the shell. 4. The sleeping bag as set forth in claim 3 wherein the at least one vent is about midway between the left and right sides of the shell. 5. The sleeping bag as set forth in claim 1 wherein the shell further comprises an end panel closing the foot end of the shell. 6. The sleeping bag as set forth in claim 5 wherein the at least one vent extends into the end panel of the shell toward the underlying portion of the shell. 7. The sleeping bag as set forth in claim 1 wherein the at least one vent is defined by adjacent edges of the shell, said edges being separable when the closure is in an open position to create said vent opening for ventilating the inner volume of the shell. 8. The sleeping bag as set forth in claim 7 wherein the shell tapers toward the foot end of the shell when the closure is in its closed position, and wherein said edges of the shell defining said vent are separable when the closure is in an open position to expand the said inner volume of the shell adjacent said foot end of the shell. 9. The sleeping bag as set forth in claim 1 wherein the closure comprises a pair of slide fasteners for selectively adjusting the size and position of the vent opening. 10. The sleeping bag as set forth in claim 1 further comprising a mesh cover attached to the shell for covering the vent opening, said mesh cover collapsing within the shell when the at least one vent is closed. 11. A vented sleeping bag comprising: an elongate shell defining a inner volume sized and shaped to receive a user therein, the elongate shell having a head end, a foot end, left and right sides extending longitudinally of the shell, an overlying portion adapted to overlie said user, and an underlying portion adapted to underlie said user; at least one longitudinal vent in said overlying portion of the shell located between the left and right sides of the shell and extending longitudinally of the shell; and a closure selectively movable between a closed position for closing said at least one longitudinal vent and an open position for creating a vent opening for ventilating the inner volume of the shell. 12. The sleeping bag as set forth in claim 11 wherein the shell further comprises an end panel at the foot end of the shell and wherein the at least one longitudinal vent is partially positioned within the overlying portion and the end panel. 13. The sleeping bag as set forth in claim 11 wherein the at least one longitudinal vent is located about midway between the left and right sides. 14. The sleeping bag as set forth in claim 11 wherein the closure comprises a pair of slide fasteners for selectively adjusting the size and position of the vent opening. 15. The sleeping bag as set forth in claim 11 further comprising a mesh cover attached to the shell for covering the vent opening, said mesh cover collapsing within the shell when the at least one longitudinal vent is closed. 16. The sleeping bag as set forth in claim 11 wherein the at least one longitudinal vent is defined by adjacent edges of the shell, said edges being separable when the closure is in said open position for ventilating the inner volume of the shell. | This application claims the benefit of U.S. Provisional Application No. 60/494,731, filed Aug. 13, 2003, titled SLEEPING BAG WITH VENTED FOOTBOX. BACKGROUND OF THE INVENTION This invention relates generally to sleeping bags, and more specifically to a sleeping bag with a vent opening selectively adjustable between an open position and a closed position for venting the inner volume of a sleeping bag. Consumers face a difficult task in finding a sleeping bag that meets their needs over a wide variety of ambient temperatures in which the bag is intended to be used. Mummy bags, which generally minimize internal volume, are shaped with a lateral taper to approximately contour the body of a person. Accordingly, these bags effectively conserve heat by decreasing air movement within the bag. As a result, mummy-type sleeping bags are well suited for use in outdoor, cold ambient temperatures. A drawback to mummy bags is that some people feel discomfort because they become too warm or the air within the bag becomes stagnant. In addition, the relatively snug fit of these bags reduces the user's range of motion, especially near the foot end of the sleeping bag. Rectangular-type sleeping bags have a generally constant lateral dimension providing generally good knee and foot room and freedom of motion. While rectangular bags are generally more spacious than mummy bags, a drawback is that their larger internal volumes make them thermally inefficient. As a result, rectangular bags are well suited for use indoors or in milder outdoor temperatures. When used in colder environments, persons using rectangular bags can more easily become chilled, especially toward their feet. Unfortunately, sleeping bag designs typically incorporate a one-type-fits-all approach. People who want to use bags in both colder and milder temperature environments typically either purchase two bags (i.e., a mummy bag and a rectangular bag) at considerable expense, or get by with one bag designed for one environment but which is less than ideal in the other environment. In addition, some users would prefer a bag that allowed the stagnant air within the bag to escape and be replaced with fresh, ambient air. Unfortunately, no single sleeping bag is available that provides all of these characteristics. SUMMARY OF THE INVENTION Among the several objects and features of the present invention may be noted the provision of a sleeping bag for insulated and personal bedding that is adapted for use both indoors and outdoors over a wide range of ambient temperatures; the provision of such a sleeping bag that is adapted for selective ventilation of the inner volume of the sleeping bag; and the provision of such a sleeping bag that is easy to use. In general, a vented sleeping bag of the present invention comprises an elongate shell defining an inner volume sized and shaped to receive a user therein. The shell has a head end, a foot end and left and right sides extending longitudinally of the shell. In addition, the shell has an overlying portion adapted to overlie a user and an underlying portion adapted to underlie the user. At least one vent is located in the overlying portion of the shell adjacent the foot end of the shell between the left and right sides of the shell. A closure on the shell is selectively movable between a closed position for closing the vent and an open position for creating a vent opening for ventilating the inner volume of the shell. In another aspect, a vented sleeping bag of the present invention comprises at least one longitudinal vent in the overlying portion of the shell between the left and right sides of the shell and extending longitudinally of the shell. A closure is selectively movable between a closed position for closing the vent and an open position for creating a vent opening for ventilating the inner volume of the shell. Other objects and features of the present invention will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a sleeping bag of the present invention having a vent which is shown in a closed position; FIG. 2 is a sectional view on line 2-2 of FIG. 1; FIG. 3 is a perspective view of the bag; FIG. 4 is a plan view of the sleeping bag with the vent shown in an open position; and Corresponding reference characters indicate corresponding parts throughout the views of the drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and in particular to FIGS. 1 and 3, a sleeping bag of the present invention is designated in its entirety by the reference number 1. As will be described hereinafter, the bag 1 has a selectively adjustable vent 3 for ventilating the sleeping bag. In general, the sleeping bag 1 comprises an elongate shell 5 that defines an inner volume sized and shaped to substantially receive a user therein. The shell 5 has a head end 7, a foot end 9 and right and left sides 11, 13 extending longitudinally of the shell. In one embodiment, the shell 5 is tapered to generally conform to the contours of a user, being broadest in the region corresponding to the shoulders of the user and narrowest in the region corresponding to the feet of the user. By generally conforming to the contours of the user and substantially receiving the user, the air movement within the sleeping bag 1 is minimized thus making the bag thermally efficient. Other shapes are also suitable. For example, the sleeping bag 1 can be generally rectangular in shape. The shell 5 comprises an inner layer 15, an outer layer 17 and insulation material (FIG. 2) disposed between the inner and layers. The outer layer 17 of the shell 5 defines the exterior of the shell and has lateral rows of stitching 18 for joining the shell to the internal insulation material. The inner layer 15 covers the inner volume of the shell 5 and is adapted for encompassing a user occupying the sleeping bag 1. The inner and outer layers 15, 17 are stitched together along their periphery edges. The insulation material, which is located between the inner and outer layers 15, 17, provides warmth and softness to the bag 1. The shell 5 has an overlying portion 19 which overlies the user and an underlying portion 21, which underlies the user, to provide padding between the user and an underlying surface. The overlying and underlying portions 19, 21 are hinged along the left side 13 of the shell 5 and have free edges along at least a portion of the right side 11 of the shell. It is understood that the overlying and underlying portions 19, 21 may be hinged to the right side 11 of the shell 5 and have free edges along the left side 13 of the shell without departing from the scope of this invention. In one embodiment, the free edges of both the overlying and underlying portions 19, 21 extend from the head end 7 of the shell 5 to approximately the transverse centerline. A pair of zipper tracks (not shown) are attached to the shell 5, one track being attached along the free edge of the overlying portion 19 and the other track attached along the free edge of the underlying portion 21. A slide fastener 20 selectively joins the zipper tracks to provide for partial separation of the overlying portion 19 from the underlying portion 21, allowing easy entry and exit by the user. In one embodiment, the shell 5 has an end panel 22 (FIG. 3) for closing the foot end 9 of the shell. The end panel 22 is stitched into the shell 5 at the foot end 9 between the overlying portion 19 and underlying portion 21. The end panel 22 provides vertical expansion of the shell 5 adjacent the foot end 9 thus adding inner volume to the region which receives the feet of a user. The illustrated sleeping bag also has a hood 23 located at the head end 7 of the shell. The hood 23 is adapted to receive the head of a user to provide warmth. A drawstring (not shown) attached along the periphery of the hood 23 allows the user to selectively open and close the face opening 25. In accordance with the present invention, the sleeping bag 1 contains one or more of the aforementioned vents 3 in the overlying portion of the shell 5. Only one such vent 3 is provided in the sleeping bag shown in the drawings, but more than one can be provided. A closure 27 is provided for selectively opening and closing the vent. When the vent 3 is closed (FIG. 1), the sleeping bag 1 provides relatively better warmth by inhibiting air movement within the inner volume. Accordingly, the sleeping bag 1 is well suited for use in colder ambient temperatures. When the vent is open (FIG. 4), a vent opening 29 is created which allows warm stagnant air within the bag 1 to escape and fresh, ambient air to enter the bag. Thus, the sleeping bag 1 is also well suited for use in mild to warm ambient temperatures. The vent 3 is defined by adjacent edges 35 of the shell 5 which are joined together when the closure is in its closed position (FIG. 1). When the closure is moved to an open position (FIG. 4), the edges 35 of the shell 5 can be separated to create a vent opening 29 of selected size. When the vent 3 is open, the interior volume of the sleeping bag 1 expands to allow greater freedom of movement for user comfort. For example, if the vent 3 is positioned adjacent the foot end 9 of the shell 5, as shown in the illustrated embodiment, moving the closure 27 to open the vent provides greater leg room for the user. A mesh cover 31 (FIG. 4) is attached to the shell 5, preferably on the inside of the shell adjacent the edges 35 defining the vent 3. When the vent is open, the cover 31 spans (covers) the vent opening 29 to prevent insects and the like from entering the bag 1. The cover also limits the extent to which the edges 35 of the shell defining the vent 3 can be separated. When the vent 3 is closed, the mesh cover 31 collapses within the shell 5. The mesh cover 31 may be attached in any suitable manner to the shell, as by stitching to the inner layer 15 of the shell. In one embodiment, the closure 27 comprises a pair of zipper tracks extending along the edges 35 of the shell which define the periphery of the opening, and a pair of slide fasteners 33. The use of two slide fasteners 33 allows greater flexibility in selecting the size and position of the vent opening 29. It will be noted in this regard that the size of the vent opening 29 can be adjusted to any size between a fully-open position and fully closed position, depending on user preference. Other types of closures can be used without departing from the scope of this invention. In the illustrated embodiment, the vent 3 extends longitudinally of the shell approximately midway between the right and left sides 11, 13 of the shell from a location adjacent the foot end 9 of the shell 5 toward the head end 7 of the shell a distance that is in the range of about 10 to 50 percent of the overall length of the shell, and even more preferably approximately one-fourth the length of the shell. Desirably, the vent 3 extends into and across the end panel 22 of the shell 5 toward the underlying portion 21 of the shell. It will be understood that the size, shape and location of the vent (and vent opening) can vary. For example, the vent 3 can run transversely with respect to the longitudinal axis of the shell, or at an oblique angle relative to such axis. Further, the vent can be placed at any location on the shell. Also, a sleeping bag of the present invention may have multiple vents of various shapes and at different locations without departing from the scope of this invention. The vent(s) can extend a shorter or longer distance along the length of the shell than shown in FIGS. 1 and 2. In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results obtained. When introducing elements of the present invention or the preferred embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. As various changes could be made in the above without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. | <SOH> BACKGROUND OF THE INVENTION <EOH>This invention relates generally to sleeping bags, and more specifically to a sleeping bag with a vent opening selectively adjustable between an open position and a closed position for venting the inner volume of a sleeping bag. Consumers face a difficult task in finding a sleeping bag that meets their needs over a wide variety of ambient temperatures in which the bag is intended to be used. Mummy bags, which generally minimize internal volume, are shaped with a lateral taper to approximately contour the body of a person. Accordingly, these bags effectively conserve heat by decreasing air movement within the bag. As a result, mummy-type sleeping bags are well suited for use in outdoor, cold ambient temperatures. A drawback to mummy bags is that some people feel discomfort because they become too warm or the air within the bag becomes stagnant. In addition, the relatively snug fit of these bags reduces the user's range of motion, especially near the foot end of the sleeping bag. Rectangular-type sleeping bags have a generally constant lateral dimension providing generally good knee and foot room and freedom of motion. While rectangular bags are generally more spacious than mummy bags, a drawback is that their larger internal volumes make them thermally inefficient. As a result, rectangular bags are well suited for use indoors or in milder outdoor temperatures. When used in colder environments, persons using rectangular bags can more easily become chilled, especially toward their feet. Unfortunately, sleeping bag designs typically incorporate a one-type-fits-all approach. People who want to use bags in both colder and milder temperature environments typically either purchase two bags (i.e., a mummy bag and a rectangular bag) at considerable expense, or get by with one bag designed for one environment but which is less than ideal in the other environment. In addition, some users would prefer a bag that allowed the stagnant air within the bag to escape and be replaced with fresh, ambient air. Unfortunately, no single sleeping bag is available that provides all of these characteristics. | <SOH> SUMMARY OF THE INVENTION <EOH>Among the several objects and features of the present invention may be noted the provision of a sleeping bag for insulated and personal bedding that is adapted for use both indoors and outdoors over a wide range of ambient temperatures; the provision of such a sleeping bag that is adapted for selective ventilation of the inner volume of the sleeping bag; and the provision of such a sleeping bag that is easy to use. In general, a vented sleeping bag of the present invention comprises an elongate shell defining an inner volume sized and shaped to receive a user therein. The shell has a head end, a foot end and left and right sides extending longitudinally of the shell. In addition, the shell has an overlying portion adapted to overlie a user and an underlying portion adapted to underlie the user. At least one vent is located in the overlying portion of the shell adjacent the foot end of the shell between the left and right sides of the shell. A closure on the shell is selectively movable between a closed position for closing the vent and an open position for creating a vent opening for ventilating the inner volume of the shell. In another aspect, a vented sleeping bag of the present invention comprises at least one longitudinal vent in the overlying portion of the shell between the left and right sides of the shell and extending longitudinally of the shell. A closure is selectively movable between a closed position for closing the vent and an open position for creating a vent opening for ventilating the inner volume of the shell. Other objects and features of the present invention will be in part apparent and in part pointed out hereinafter. | 20040409 | 20101214 | 20050217 | 76453.0 | 0 | SAFAVI, MICHAEL | SLEEPING BAG WITH VENTED FOOTBOX | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,821,426 | ACCEPTED | Process for preparation of probucol derivatives | A method is described for the preparation of polymorphic forms of water-soluble derivatives of probucol compounds having the following formula where R1, R2, R3, R4, R5, R6, Z and Z′ are defined herein. | 1. In a process for the preparation of a water-soluble derivative of probucol having the following formula where R1 and R2 are the same or different and are —C1-C6 alkyl, —C3-C6 alkenyl or aryl, R3, R4, R5 and R6 are the same or different and are C1-C6 alkyl, Z and Z′ are the same or different and are hydrogen or the group —C(O)—C1 to C6-alkyl-C(O)OH where Z and Z′ can not both be hydrogen by (1) the reaction of a probucol compound of the formula where R1, R2, R3, R4, R5 and R6 are as previously defined with a compound selected from the group consisting alkali metal hydroxide, alkali metal alkoxide, alkyl ammonium alkoxide, alkyl ammonium hydroxide and mixtures thereof thereby forming an ammonium or alkali metal salt of said probucol compound (2) reacting said salt with a carboxylic acid anhydride to form a reaction mixture and (3) separating said water soluble probucol derivative from said reaction mixture the improvement comprising using as a solvent for reaction step 1 a compound having the formula R—C(O)—R′, where R and R′ are the same or different and are C1 to C6 alkyl, C2 to C6 alkenyl, C6 to C12 aryl, C6 to C12 aryl substituted with at least one C1 to C6 alkyl, C5 to C12 heteroaryl or C5 to C12 heteroaryl substituted with at least one C1 to C6 alkyl 2. In the process according to claim 1 wherein R and R′ are the same or different and are C1 to C6 alkyl. 3. In the process according to claim 2 wherein R and R′ are methyl or ethyl. 4. In the process according to claim 3 wherein R and R′ are methyl. 5. In the process according to claim 1 wherein the ratio of said solvent to the probucol derivative is from about 2:1 to about 1:5. 6. In the process according to claim 5 wherein the ratio is from about 1:1 to about 3:10. 7. In the process according to claim 6 wherein the ratio is 3:5. 8. In the process according to claim 1 the reaction temperature of step (a) is from about 15° to about 75° C. 9. In the process according to claim 8 wherein said reaction temperature is from about 30° to about 60° C. 10. In the process according to claim 9 wherein said reaction temperature is from about 35° to about 45° C. 11. In the process according to claim 1 wherein the pH of the reaction mixture formed in reaction step (2) is reduced to less than 7 and then an organic hydrocarbon solvent having the formula CnH2n+2 where n is an integer from 5 to 12 is added to the reduced pH reaction mixture. 12. In the process according to claim 11 wherein the integer n of the hydrocarbon solvent is 6 to 9. 13. In the process according to claim 12 wherein the hydrocarbon solvent is hexane or heptane. 14. In the process according to claim 13 wherein the hydrocarbon solvent is admixed with the compounds of Formula 2 at temperatures >40° C. but not above 150° C. 15. In the process according to claim 14 wherein the temperature is about 45° to about 75° C. | FIELD OF INVENTION The present invention relates to 4,4′-(isopropylidenedithio) bis[2,6-di-tert-butylphenol], known and referred to herein by its generic name “probucol”, and to derivatives of probucol. More particularly, this invention relates to an improved process for the preparation of probucol derivatives BACKGROUND OF THE INVENTION Probucol is a well-known antioxidant that is related to antioxidant compounds such as 2-(3)-tertiary butyl-4-hydroxyanisole, 2,6-di-tertiary butyl-4-methylphenol and the like. These compounds are used in food and food products to prevent oxidative deterioration. Probucol is represented by the following structural formula The preparation of this compound is a multistep process, typically starting by reacting a solution of the appropriately-substituted 4-mercaptophenol with acetone, in the presence of a catalytic amount of a strong acid. Probucol precipitates from the reaction mixture and is readily separated and purified. The reaction is described in detail in U.S. Pat. No. 3,862,332 (Barhhart et al). Similarly, probucol and certain of its derivatives are also described in U.S. Pat. No. 3,485,843 (Wang), U.S. Pat. No. 3,576,833 (Neuworth) and U.S. Pat. No. 4,985,465 (Handler). Probucol and its derivatives possess pharmaceutical properties that include antiatherogenesis, lipid lowering and the like. But probucol and numerous of its derivatives are poorly soluble in body fluids. In order to avoid the low water solubility problems associated with probucol utilization in the body, more water-soluble derivatives have been prepared. Thus, U.S. Pat. No. 5,262,439 (Parthasarathy), incorporated herein in its entirety by reference, discloses a class of water-soluble probucol derivatives having one or more ester groups replacing the phenolic hydroxyl group of the probucol molecule. Some of the compounds disclosed in this reference have polar or charged functionalities attached to the ester group, e.g., the groups carboxylic acid, amide, amino, and aldehyde. The method disclosed for preparing these water-soluble probucol compounds involves the reaction of probucol with the carboxylic acid anhydride compound bearing the desired polar or charged functionality in the presence of a catalyst. Similarly, U.S. Pat. Nos. 6,323,359 and 6,548,699 also disclose water soluble derivatives of probucol. The compounds set forth in the former patent are produced by a process involving the reaction of a probucol dianion with carboxylic acid anhydrides. The compounds disclosed in U.S. Pat. No. 6,548,699 are synthesized by reaction of probucol with, inter alia, halo-substituted aliphatic esters. The prior art processes are disadvantageous, since they are not effective in producing the desired alkylated derivatives of probucol in any appreciable yields. Accordingly, it is desirable to have available a process to efficiently prepare probucol derivatives in high yields. SUMMARY OF THE INVENTION The process of the present invention is an improvement in a process whereby probucol is reacted with an alkali metal or ammonium-containing compound to produce, as a mixture, the mono- and dialkali metal salts of probucol, e.g, the mono- or dialkali metal salt of 4,4′-(isopropylidenedithio) bis[2,6-di-tert- butylphenol] or its derivatives. This anionic intermediate mixture is then reacted with a carboxylic acid anhydride such as succinic acid anhydride, glutaric acid anhydride, adipic acid anhydride, suberic acid anhydride, sebacic acid anhydride, azelaic acid anhydride, phthalic acid anhydride or maleic acid anhydride to form a reaction mixture of dicarboxylic acid-substituted probucol compounds. These water soluble probucol compounds are then separated from said reaction mixture. The improved prior art process comprises carrying out the first step of the reaction that produces the mono or dialkali metal salts by using, as a solvent, a compound having the formula R—C(O)—R′, where R and R′ are the same or different and are C1 to C6 alkyl, C2 to C6 alkenyl, C6 to C12 aryl, C6 to C12 aryl substituted with at least one C1 to C6 alkyl, C5 to C12 heteroaryl or C5 to C12 heteroaryl substituted with at least one C1 to C6 alkyl. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a process for preparing certain water soluble probucol derivatives. As used herein, the term “C1 to C8 alkyl” is intended to mean and include the groups that are C1 to C8 linear or branched alkyl which include the moieties methyl, ethyl, n-propyl, isopropyl, butyl, sec-butyl, tert-butyl, n-pentyl, 2-methylpentyl, n-heptyl, n-octyl and the like. The term “C6 to C12 aryl” is intended to mean and include the aromatic radicals having 6 to 12 carbon atoms in the aromatic ring system that may be substituted or unsubstituted one or more times by alkyl, nitro or halo which includes phenyl, naphthyl, phenanthryl, anthracenyl, thienyl, pyrazolyl and the like. The term “C3 to C6 alkenyl” is intended to mean and include the groups that are C3 to C6 linear or branched alkenyl which include the moieties 1-propenyl, 1-butenyl, 2-butenyl, 1-pentenyl, 2-pentenyl and the like. The term “alkali metal” is intended to mean those metals in Group I and Ia of the Periodic Table of the Elements such as lithium, potassium, sodium and the like. The water-soluble derivatives of the probucol compounds herein are obtained by reaction of a solution of one or both of the hydroxyl groups of probucol or the probucol derivative with a compound that forms an alkali metal or ammoniun salt of probucol, i.e., the alkali metal or ammonium substitutes for hydrogen at one or both of probucol's hydroxyl groups. The compounds that form these salts are strongly basic reactants. They are illustrated by the alkali metal hydrides, alkali metal hydroxides, alkali metal alkoxides, alkyl ammonium alkoxides or alkyl ammonium hydroxides. Mixtures of these compounds are also useful in producing the desired probucol salts. Potassium is the most preferred alkali metal of these strongly basic reactants used in this step. The process is described in U.S. Pat. No. 6,323,359 and is incorporated herein by reference. It has been discovered that by using a ketone solvent in this salt-forming reaction, that yields of product probucol compounds are enhanced. The ketone solvent used to carry out this salt-forming reaction has the formula R—C(O)—R′, where R and R′ are the same or different and are C1 to C6 alkyl, C3 to C6 alkenyl, C6 to C12 aryl, C6 to C12 aryl substituted with at least one C1 to C6 alkyl, C5 to C12 heteroaryl or C5 to C12 heteroaryl substituted with at least one C1 to C6 alkyl. Mixtures of these ketone solvents may also be used. It is preferred that R and R′ are the same or different and are C1 to C6 alkyl, most preferably the groups methyl or ethyl. Particularly preferred for the solvent in this reaction is acetone. The concentration of probucol or its derivatives in the above salt-forming reaction is dramatically higher than that disclosed in similar prior art reactions. Thus, in carrying out the salt-forming reaction, the ratio of solvent to probucol derivative is from about 2:1 to about 1:5, preferably about 1:1 to about 3:10, most preferably 3:5. A further advantage of the reaction of probucol of the probucol derivative with the alkali metal or ammonium compounds lies in the discovery that the reaction temperature is critical to effecting enhanced salt-forming conversions. Thus, the salt-forming reaction is carried out at temperatures from about 15° to about 75° C., preferably from about 30° to about 60° C., most preferably from about 35° to about 45° C. Thus, this first reaction in the process (reaction step 1) of the present invention described above, produces a mixture of mono- and dianions of the following Formula 1 (where each A may a proton, an alkali metal cation or an ammonium cation) where R1 and R2 are the same or different and are alkyl, alkenyl or aryl having from 1 to 8 carbon atoms and R3, R4, R5 and R6 are the same or different and are alkyl having from 1 to 4 carbon atoms. Preferably, R1 and R2 are the same and are alkyl having from 1 to 6 carbon atoms, most preferably methyl. Preferably R3, R4, R5 and R6 are the same and are alkyl having from 1 to 4 carbon atoms, most preferably tert-butyl The mixture of mono- and dialkali metal or ammonium salt of the probucol derivative readily forms in as little as 30 minutes or up to about six hours after such admixing, typically at about 40° C. The diphenolate salt may be removed from the reaction solution as a solid (by precipitation and filtration, etc.) and subsequently used in step 2 of the process, or the reaction solution resulting from step 1 of the reaction can be used “as is” for the second step, i.e., without separating the mixture of mono- and dianions. In either case, the salt produced in the first step is treated with the acid anhydride which reacts with at least one of the alkali metal or ammonium probucol phenolates. However, it should be noted that because there are two reactive sites available in the mono- and dianionic mixture, either one or both of these sites can be substituted by the incoming acid anhydride moiety. The subsequent reaction of the compounds of Formula 1 with an acid anhydride such as succinic acid anhydride, glutaric acid anhydride, adipic acid anhydride, suberic acid anhydride, sebacic acid anhydride, azelaic acid anhydride, phthalic acid anhydride or maleic acid anhydride produces the compounds of the Formula 2 below where Z and Z′ are the same or different and are hydrogen, or the moiety —C(O)—C1 to C6 alkyl C(O)OA or the moiety —C(O)—C3 to C6-alkenyl C(O)OA where A is an alkali metal or ammonium cation and alkyl and alkenyl are as previously defined, with the proviso that Z and Z′ can not both be hydrogen. Preferably, Z and Z′ are different and are hydrogen and —C(O)—C1-C6 alkyl C(O)OA most preferably hydrogen and the group —C(O)—CH2—C(O)OA. The above substitution reaction is typically carried out from 30 minutes to about six hours in an organic solvent. As noted, two probucol derivatives may be formed, i.e., the desired mono substitution product, where Z and Z′ are different and are hydrogen and the moiety —C(O)—C1 to C6 -alkyl C(O)OA or the moiety —C(O)—C3 to C6 alkenyl-C(O)OA where A is an alkali metal or ammonium cation and alkyl, and alkenyl are as previously defined or the disubstitution product, where Z and Z′ are the same and are the moiety the moiety —C(O)—C1 to C6-alkyl C(O)OA or the moiety —C(O)—C3 to C6 alkenyl-C(O)OA where A is an alkali metal or ammonium cation and alkyl, and alkenyl are as previously defined. The reaction mixture to produce the compounds of Formula 2 has a pH of from about 9 to about 14 and typically contains the unreacted probucol or probucol derivative as well as the mono and di substitution products of Formula 2. As such, and as a further embodiment of the present invention, an organic hydrocarbon solvent having the formula CnH2n+2 where n is an integer from 5 to 12 is added to this highly basic reaction mixture formed from the reaction of acid anhydride and probucol or probucol derivative. The hydrocarbon solvent dissolves unreacted probucol or probucol derivative and leaves a solution of the alkali metal or ammonium salts of the compounds of Formula 2 in the solvent R—C(O)R′ where R and R′ are as previously defined. The solution of the compounds of Formula 2 is acidified in the presence of the same or a different organic hydrocarbon solvent that was previously used to remove the unreacted probucol or probucol derivative, i.e., a hydrocarbon solvent having the formula CnH2n+2 where n is an integer from 5 to 12. The hydrocarbon solvent preferentially dissolves the compounds of Formula 2 where Z and Z′ are different and are hydrogen and the moiety C(O)—C1 to C6-alkyl C(O)OH or the moiety —C(O)—C3 to C6 alkenyl-C(O)OH where alkyl , and alkenyl are as previously defined. It is preferred that the integer n of the hydrocarbon solvent is 6 to 9, Most preferably the hydrocarbon solvent is hexane, heptane or octane. The formation of the acidified solution of the compounds of Formula 2 using the hydrocarbon solvent is carried out at temperatures >40° C. but not above 150° C. Preferably the temperature of the solvent-forming solution is about 45° to about 85° C. As a final step in the process of the present invention used to prepare the water soluble probucol compounds is the purification of the compounds of Formula 2, i.e., the compounds where Z and Z′ are the same or different and are hydrogen, or the moiety —C(O)—C1 to C6 alkyl C(O)OH or the moiety —C(O)—C3 to C6-alkenyl C(O)OH where alkyl and alkenyl are as previously defined, with the proviso that Z and Z′ can not both be hydrogen. As such, the compounds of Formula 2 obtained as a solution as set forth above are separated from the hydrocarbon solvent or the dibasic ester solvent as a solid material by conventional means (cooling, distillation to remove the solvent, etc.). This solid material is then redissolved in a typically aromatic solvent such as benzene, toluene, etc. and passed through a bed of impurity-removing compound, e.g., activated carbon, clay, silica gel, etc. The resulting solution is essentially a solution of the desired compound of Formula 2. Conventional separation processes produce the final crystalline product. The present invention is described in detail in the examples set forth below which are provided by way of illustration only and therefore should not be considered as limiting the scope of the invention. EXAMPLES Synthesis of Water Soluble Derivatives of Probucol General Process Example 1 In an appropriately sized vessel, probucol (1 equivalent) and acetone (60 weight percent) are combined. With agitation potassium tert-butoxide (0.67 equivalent) is charged and the resultant solution warmed to ˜40° C. for about 45 minutes. Succinic anhydride (0.67 equivalent) is charged and the system stirred at ˜40° C. for at least 30 minutes. A dark reaction mixture forms which is a combination of the salts of di-succinylated probucol (DSP), mono-succinylated probucol (MSP) and unreacted probucol (PRO). The ratio of DSP:MSP:PRO is about 4:29:67. Example 2 The reaction mixture of Example 1 is cooled to ˜30° C., water is added and the pH of the reaction mixture is adjusted to >13 with 45% aqueous potassium hydroxide. The aqueous system is extracted three times with heptane. The probucol-rich heptane extractions are saved for recycle, while the aqueous acetone phase is saved for trituration. Example 3 To the acetone solution of Example 2, is charged acetone (20 volume percent) and the pH of the system is adjusted to <3 with 85 weight percent (wt %) aqueous phosphoric acid. The acidified solution is mixed for at least 30 minutes and the resulting solids, which are predominately dibasic potassium acid phosphate, are filtered and discarded. The lower, aqueous phase of the resulting two phase filtrate is separated and discarded, reserving the acetone phase. Acetone is removed from the reserved phase by distillation and heptane is added. The resultant slurry is triturated at 75-85° C. for about 30 minutes and filtered. The solid residue is reserved for later extraction. Upon cooling, the product-rich heptane filtrate provides a solid that is approximately 25 mol percent of material having the ratio 2:98, DSP:MSP Example 4 This MSP-enriched material from Example 3 is dissolved in toluene, then washed with 45% KOH. The toluene solution is dried with potassium carbonate and the solids removed by filtration. The toluene solution is then passed through clay absorb 24/48 to remove DSP. Example 5 The toluene solution collected from Example 4 is washed once with 43% aqueous H3PO4 and once with water. The toluene solution is distilled to dryness and slurried with hot heptane. The heptane slurry is cooled and filtered. The solid residue is MSP. It is washed with heptane and dried at 70° C. under vacuum. A yield of approximately 15 to 25 mol percent MSP is obtained. Specific Process Example 6 In an appropriate-sized vessel, probucol (500 g, 0.97 mol) and acetone (300 g) are combined. With agitation potassium tert-butoxide (73 g, 0.65 mol) is charged and the resultant solution warmed to ˜40° C. for at least 45 minutes. Succinic anhydride (65 g, 0.65 mol) is charged and the system stirred at ˜40° C. for at least 30 minutes. A dark reaction mixture forms which is a combination of the salt of di-succinylated probucol (DSP), the salt of mono-succinylated probucol (MSP) and unreacted probucol (PRO). The ratio of DSP:MSP:PRO is about 4:29:67. The reaction mixture is cooled to ˜30° C., water (300 g) is added and the pH of the reaction mixture is adjusted to >13 with 45% aqueous potassium hydroxide (KOH) (about 40 g). The aqueous system is extracted three times with heptane (513 g for each extraction). The probucol-rich heptane extractions are saved for recycle, while the aqueous acetone phase is saved for trituration. To the above-saved acetone solution, acetone is charged (158 g) and the pH of the system is adjusted to <3 with 85 wt % aqueous phosphoric acid (145 g). Additional acetone (200 g) is charged and the acidified solution is mixed for at least 30 minutes. The lower, aqueous phase is separated and discarded, reserving the acetone phase. Acetone is removed from the reserved phase by distillation and heptane (665 g) is added. The resultant slurry is triturated at 80° C. for about 30 minutes and filtered. The solid residue is reserved for later extraction. The product-rich heptane filtrate is cooled to ˜20° C., and the resulting precipitated MSP-enriched solids are collected by filtration. The 80° C. trituration process is repeated two more times with 410 g and 310 g of heptane, providing 133 g of a solid that is approximately 2:98, DSP:MSP. This MSP-enriched material is dissolved in toluene (500 mL), then washed with 45 g of 45% KOH. The toluene solution is mixed with potassium carbonate (44 g) for not more then 30 minutes and the solids removed by filtration. The toluene solution is then passed through clay absorb 24/48 (135 g, two passes). After each pass, the clay bed is washed twice with toluene (175 g). The toluene solution collected from the passes through the clay absorb is washed once with 43% aqueous H3PO4 (300 g) and once with water (300 g). The toluene solution is distilled to dryness and the resulting residue slurried with heptane (275 g) at 80° C. for no longer than 30 minutes. The heptane slurry is cooled to 10° C. and filtered. The solid residue is MSP. It is washed with heptane (2×70 g) and dried at 70° C. under vacuum for approximately 3 hours. A yield of 97 g, 16 mol % is obtained. | <SOH> BACKGROUND OF THE INVENTION <EOH>Probucol is a well-known antioxidant that is related to antioxidant compounds such as 2-(3)-tertiary butyl-4-hydroxyanisole, 2,6-di-tertiary butyl-4-methylphenol and the like. These compounds are used in food and food products to prevent oxidative deterioration. Probucol is represented by the following structural formula The preparation of this compound is a multistep process, typically starting by reacting a solution of the appropriately-substituted 4-mercaptophenol with acetone, in the presence of a catalytic amount of a strong acid. Probucol precipitates from the reaction mixture and is readily separated and purified. The reaction is described in detail in U.S. Pat. No. 3,862,332 (Barhhart et al). Similarly, probucol and certain of its derivatives are also described in U.S. Pat. No. 3,485,843 (Wang), U.S. Pat. No. 3,576,833 (Neuworth) and U.S. Pat. No. 4,985,465 (Handler). Probucol and its derivatives possess pharmaceutical properties that include antiatherogenesis, lipid lowering and the like. But probucol and numerous of its derivatives are poorly soluble in body fluids. In order to avoid the low water solubility problems associated with probucol utilization in the body, more water-soluble derivatives have been prepared. Thus, U.S. Pat. No. 5,262,439 (Parthasarathy), incorporated herein in its entirety by reference, discloses a class of water-soluble probucol derivatives having one or more ester groups replacing the phenolic hydroxyl group of the probucol molecule. Some of the compounds disclosed in this reference have polar or charged functionalities attached to the ester group, e.g., the groups carboxylic acid, amide, amino, and aldehyde. The method disclosed for preparing these water-soluble probucol compounds involves the reaction of probucol with the carboxylic acid anhydride compound bearing the desired polar or charged functionality in the presence of a catalyst. Similarly, U.S. Pat. Nos. 6,323,359 and 6,548,699 also disclose water soluble derivatives of probucol. The compounds set forth in the former patent are produced by a process involving the reaction of a probucol dianion with carboxylic acid anhydrides. The compounds disclosed in U.S. Pat. No. 6,548,699 are synthesized by reaction of probucol with, inter alia, halo-substituted aliphatic esters. The prior art processes are disadvantageous, since they are not effective in producing the desired alkylated derivatives of probucol in any appreciable yields. Accordingly, it is desirable to have available a process to efficiently prepare probucol derivatives in high yields. | <SOH> SUMMARY OF THE INVENTION <EOH>The process of the present invention is an improvement in a process whereby probucol is reacted with an alkali metal or ammonium-containing compound to produce, as a mixture, the mono- and dialkali metal salts of probucol, e.g, the mono- or dialkali metal salt of 4,4′-(isopropylidenedithio) bis[2,6-di-tert- butylphenol] or its derivatives. This anionic intermediate mixture is then reacted with a carboxylic acid anhydride such as succinic acid anhydride, glutaric acid anhydride, adipic acid anhydride, suberic acid anhydride, sebacic acid anhydride, azelaic acid anhydride, phthalic acid anhydride or maleic acid anhydride to form a reaction mixture of dicarboxylic acid-substituted probucol compounds. These water soluble probucol compounds are then separated from said reaction mixture. The improved prior art process comprises carrying out the first step of the reaction that produces the mono or dialkali metal salts by using, as a solvent, a compound having the formula R—C(O)—R′, where R and R′ are the same or different and are C 1 to C 6 alkyl, C 2 to C 6 alkenyl, C 6 to C 12 aryl, C 6 to C 12 aryl substituted with at least one C 1 to C 6 alkyl, C 5 to C 12 heteroaryl or C 5 to C 12 heteroaryl substituted with at least one C 1 to C 6 alkyl. detailed-description description="Detailed Description" end="lead"? | 20040409 | 20071113 | 20051013 | 94546.0 | 0 | VALENROD, YEVGENY | PROCESS FOR PREPARATION OF PROBUCOL DERIVATIVES | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,821,666 | ACCEPTED | Intelligent power distribution system | An intelligent power distribution system including one or more intelligent power strips. The power strips can each include an elongated housing that may be adapted for mounting in an equipment rack. The housing can include a first end, a second end and plurality of power outlets mounted thereon. The first end can have a number of apertures that enable power and signal conductors to enter an interior region of the housing. The second end can include a first and a second communication port. The first communication port may be adapted to enable a computer to communicate with the power the strip. The second communication port may be adapted to enable the power the strip to be daisy chained with a second intelligent power strip. The power strip further includes power management circuitry that can power-on and power-off the power outlets in accordance with an operator defined sequence and delays. The power management circuitry can further sense electrical current drawn by the power strip and control operation of the power strip based on the sensed electrical current to minimize branch circuit breaker tripping. | 1-32. (canceled) 33. A power strip, comprising: a housing having a first end and a second end; at least one power outlet mounted on an exterior surface of the housing; a power management circuit defined on an interior region of the housing, including: a micro-controller coupled to the power supply and to a relay driver, the relay driver receiving control signals from the micro-controller; an input power source sensor circuit is coupled intermediate the power supply and the micro-controller, to receive primary input power from the power supply and secondary input power from a secondary power source, whereby the input power source sensor circuit provides the primary input power to the micro-controller and if the primary input power fails, the input power source sensor circuit provides the secondary input power to the micro-controller; and at least one relay coupled to the relay driver and to the at least one power outlet, wherein the relay receives a control signal from the relay driver to actuate the relay to a conductive state to powering-on the power outlet and the relay receives another control signal from the relay driver to actuate the relay to a non-conductive state to powering-off the power outlet; and an under voltage sensor coupled to the micro-controller and adapted to receive a predetermined voltage value from the power supply. 34. The power strip of claim 33, wherein the at least one power outlet comprises a plurality of power outlets, the plurality of power outlets comprising a first group of power outlets and a second group of power outlets, the first group being coupled to the sensor circuit and the second group being coupled to the sensor circuit via the at least one relay. 35. The power strip of claim 34, wherein the power strip further includes a plurality of communication ports. 36. The power strip of claim 35, wherein the communication ports include a first communication port coupled to a communication-in circuit and a second communication port coupled to a communication-out circuit, the communication-in circuit and the communication-out circuit being further coupled the micro-controller. 37. The power strip of claim 36, wherein the communication-in circuit includes the secondary power source. 38. The power strip of claim 37, wherein the under voltage sensor is responsive to the predetermined voltage-value falling below a predetermined threshold value by providing a reset signal to the micro-controller. 39. The power strip of claim 38, wherein the micro-controller is further coupled to a non-volatile memory device. 40. The power strip of claim 39, wherein the micro-controller is further coupled to an audible alarm that can alert an operator that current on the input power line has exceeded a predetermined threshold value. 41. The power strip of claim 40, wherein the micro-controller is further coupled to a mute button that which is actuated to silence the audible alarm. 42. The power strip of claim 41, wherein the micro-controller is further coupled to an overload light-emitting-diode which is controlled to illuminate with a predetermined frequency to indicate an overload status of the input power line. 43. The power strip of claim 42, wherein the second group of power outlets includes a plurality of light emitting diodes that can each be controlled to illuminate to indicate that an associated outlet is powered-on. 44. The power strip of claim 33 further comprising a current sensor circuit that is adapted to receive input power over an input power line, the current sensor circuit being coupled to a power supply and to the at least one power outlet; 45. A power distribution method comprising the steps of: energizing an input power line to power-up a group of power outlets on a power distribution system; initializing the power strip according to at least one system parameter or at least one operating configuration; and controlling a relay to actuate to a conductive state in accordance with a predetermined sequence and a predetermined delay to sequentially power-on at least one of the power outlets in the group of power outlets on the power distribution system. 46. The power distribution method of claim 45, wherein intializing according to a system parameter or an operating configuration includes the steps of: programming a normal-threshold value into the power distribution system; programming an overload-threshold value into the power distribution system; programming an under-voltage threshold value into the power distribution system; programming delays into the power distribution system, the delays being related to powering-on and powering-off the second group of power outlets; and programming the sequence for which the second group of power outlets is powered-on and powered-off. 47. The power distribution method of claim 46, wherein the method further includes: sensing current on the input power line; providing the sensed current to a micro-controller; and determining if the sensed current is below the normal-threshold value, wherein if the sensed current is below the normal-threshold value, the method further includes indicating a normal operation of the power distribution system. 48. The power distribution method of claim 47, wherein the method further includes the steps of: determining if the sensed current is above the normal-threshold value; and determining if the sensed current is below the overload-threshold value, wherein if the sensed current is above the normal-threshold value and below the overload-threshold value, the method further includes indicating a high current status of the power distribution system. 49. The power distribution method of claim 48, wherein the method further includes the step of: determining if the sensed current is above the overload-threshold value, wherein if the sensed current is above the overload-threshold value, the method further includes indicating an alarm status of the power distribution system. 50. The power distribution method of claim 49, wherein if the sensed current is above the normal-threshold value and below the overload-threshold value, the method further includes controlling a first group of predetermined relays to actuate to a non-conductive state to power-off a number of associated power outlets. 51. The power distribution method of claim 50, wherein if the sensed current is above the overload-threshold value, the method further includes controlling a second group of predetermined relays to actuate to a non-conductive state to power-off a number of associated power outlets. 52. The power distribution method of claim 51, wherein the method further includes: controlling the plurality of relays to actuate to a non-conductive state in accordance with a predetermined sequence and a predetermined delay to sequentially power-off the second group of power outlets which are coupled to the relays; and de-energizing the input power line defined on the power strip to power-off the first group of power outlets defined on the power strip. 53. The power distribution method of claim 52, wherein powering-on the second group of power outlets further includes illuminating a plurality of light-emitting-diodes associated with the second group of power outlets. 54. The power distribution method of claim 53, wherein the method further includes programming a maximum current draw value. 55. A power distribution system, comprising: a plurality of power strips, the power strips being mounted in an equipment rack, the equipment rack having a number of slots adapted to securely hold a number of pieces of equipment, each power strip including: a housing having a first end and a second end; at least one power outlet mounted on an exterior surface of the housing; a power management circuit defined on an interior region of the housing, including: a micro-controller coupled to the power supply and to a relay driver, the relay driver receiving control signals from the micro-controller; and at least one relay coupled to the relay driver and to the at least one power outlet, wherein the relay receives a control signal from the relay driver to actuate the relay to a conductive state to powering-on the power outlet and the relay receives another control signal from the relay driver to actuate the relay to a non-conductive state to powering-off the power outlet. 56. The power distribution system of claim 55, wherein the power strips mounted in the equipment rack are daisy chained together to form a scalable power strip. 57. The power distribution system of claim 55, further comprising a current sensor circuit adapted to receive input power over an input power line, the current sensor circuit being coupled to a power supply and to the at least one power outlet. | FIELD OF THE INVENTION The present invention generally relates to an intelligent power distribution system and method, and more particularly to an intelligent power strip and method of distributing power in an electronic system. BACKGROUND Many electronic and electrical systems, such as computer and home entertainment systems, require that electrical power be applied to components of the system according to a particular sequence to avoid causing undue stress and possible damage to the components. Particularly with computer systems, there are many situations in which it is advantageous to delay activation of peripheral devices until after the parent device is powered up and has attained a quiescent state. A typical situation is that of a personal or business computer system where the activation of peripheral devices including a monitor, disk drives and printers, are delayed until after the computer itself is fully on-line. Upon activation of the parent device and after the parent device reaches a quiescent operating state, power can be applied to the peripheral devices. This sequence of powering up a computer system is especially helpful in eliminating undesirable transient currents and random logic states caused by simultaneous power up of the parent and peripheral devices. For example, in many computer systems, power is first applied to the computer itself before power is applied to the monitor, because the computer supplies the monitor with horizontal and vertical synchronization pulses necessary to prevent the free running of the monitor's horizontal and vertical oscillators. Allowing the oscillators to operate in an unsynchronized condition can result in undue stress to the oscillators and hard failure of the monitor. Similarly, power is applied to the computer before power is applied to the printer. Otherwise, the printer can potentially back-feed power or control signals to the computer and cause the computer to fail to initialize when the computer subsequently receives power. Consequently, the order and timing of the application of power to and removal of power from certain systems needs to be carefully controlled so as to avoid damaging the system components. One solution for providing power to systems similar to that described above includes employing an operator to manually turn on the components. Specifically, the operator can power on the computer itself and pause momentarily to allow sufficient time for the computer to reach a quiescent operating state before providing power to the computer's peripheral devices. This method is generally unsatisfactory, because the time delay interval is difficult to control and duplicate manually, and further, because it may be desirable to ensure that the power up and power down of the system always occur according to a particular sequence. Another solution is to use time delay relays (“TDRs”) to provide a predetermined, fixed time delay between application of power to one component and the next. This method is also unsatisfactory, as well as being very expensive. TDRs are capable only of providing a fixed, or at best, a narrowly adjustable, time delay. Furthermore, the power up delay is typically equal to the power down delay, a condition which may be undesirable in certain cases. Finally, the time delay provided by the TDRs is typically not easy to adjust by an operator. Therefore, a need exists for an intelligent power distribution system that can provide power up and/or power down sequences and delays for equipment, which overcomes limitations and deficiencies of the prior art. SUMMARY OF THE INVENTION It is an object of the present invention to provide an intelligent power distribution system and method for using the power distribution system. In embodiments of the present invention, the intelligent power distribution system can manage power consumption to minimize tripping of a branch circuit breaker which provides electrical power to the system. In one aspect of the present invention, a power distribution system can include a plurality of intelligent power strips that can be adapted for mounting in an equipment rack. The power strips can be individually mounted and controlled or the power strips can be daisy chained together to form a scalable power strip which can be unitarily controlled. The equipment rack can have a number of slots that may be adapted to securely hold a number of pieces of equipment thereon. Each intelligent power strip can include a housing that has a first end and a second end. A plurality of power outlets can be mounted on an exterior surface of the housing to provide power to the equipment. An aperture can be formed on the first end of the housing to enable power and signal conductors to access an interior region of the housing. A first communication port and a second communication port can be defined on the second end of the housing. The first communication port can include a communication-in circuit that enables bi-directional communication with the power strip and the second communication port can include a communication-out circuit that enables the power strip to be coupled to a second power strip. The intelligent power strip can further include a power management circuit which is defined in the interior region of the housing. The power management circuit can include a current sensor circuit that may be adapted to receive alternating current (“AC”) input power over an AC input power line. The current sensor circuit can be coupled to the power outlets as well as to an AC to direct current (“DC”) power supply. The AC to DC power supply receives and processes AC power from the current sensor circuit to generate a plurality of DC voltage values. The micro-controller can be coupled to the power supply and can receive one or more voltage values from the power supply. The micro-controller may be further coupled to a relay driver. The relay driver can receive control signals from the micro-controller to control a plurality of relays coupled to the relay driver. The relays can be coupled to the power outlets defined on the housing of the power strip. The relays can be controlled to a conductive state to power-on the power outlets and the relays can be controlled to a non-conductive state to power-off the power outlets. The power outlets defined on the power strip can include a first group of power outlets and a second group of power outlets. The first group of power outlets can be coupled to the sensor circuit and the second group of power outlets can be coupled to the sensor circuit via the relays. The second group of power outlets can each include a light-emitting-diode (“LED”) that can be controlled to illuminate to indicate that each power outlet is powered-on. The power management circuit can further include an input power source sensor circuit. The input power source sensor circuit can be coupled intermediate the power supply and the micro-controller. The input power source sensor circuit can receive DC input power from the power supply that is hereinafter defined as primary DC input power, which can be provided to the micro-controller. The input power source sensor circuit can further receive secondary DC input power from a secondary power source. The secondary power source can be provided by the communication-in circuit and can provide a redundant power source for the micro-controller. In the event that the primary DC input power provided by the power supply fails or is unavailable, the input power source sensor circuit can provide the secondary DC input power to the micro-controller. The micro-controller can be further coupled to an under voltage sensor. The under voltage sensor can be adapted to receive a predetermined voltage value from the power supply. The under voltage sensor can be responsive to the predetermined voltage value falling below a predetermined threshold value by providing a reset signal to the micro-controller. The predetermined threshold value can be defined by a user of the intelligent power distribution system. A non-volatile memory device can also be coupled to micro-controller to enable the micro-controller to store initialization and configuration information as well as other operating parameters. The micro-controller can also be coupled to an audible alarm that can alert an operator that current on the input power line has exceeded a predetermined threshold value. A mute button coupled to the micro-controller can be actuated to silence the audible alarm. An overload LED, which is coupled to the micro-controller, can be controlled to illuminate with a predetermined frequency to indicate an overload status of the input power line. In another aspect of the present invention, a power distribution method includes energizing an input power line to power-up a first group of power outlets on a power distribution system; and controlling a plurality of relays to actuate to a conductive state in accordance with a predetermined sequence and predetermined delay to sequentially power-on a second group of power outlets defined on the power distribution system. Powering-on the second group of power outlets further includes illuminating a light-emitting-diode associated with each power outlet, defined in the second group, to indicate a powered-on status of the second group of power outlets. Initializing the power distribution system can include programming a normal-threshold value into the power distribution system; programming an overload-threshold value into the power distribution system; programming an under-voltage threshold value into the power distribution system; programming delays into the power distribution system, the delays can be related to powering-on and powering-off power outlets defined in the second group; and programming the sequence for which power outlets can be powered-on and powered-off. The method can further include sensing current on the input power line; providing the sensed current to a micro-controller; and determining if the sensed current is below the normal-threshold value. If the sensed current is determined to be below the normal-threshold value then the method further includes indicating a normal operating status of the power distribution system. The method can further include determining if the sensed current is above the normal-threshold value; and determining if the sensed current is below the overload-threshold value. If the sensed current is determined to be above the normal-threshold value and below the overload-threshold value, the method further includes indicating a high current status of the power distribution system. The method can further include determining if the sensed current is above the overload-threshold value. If the sensed current is determined to be above the overload-threshold value, the method further includes indicating an alarm status of the power distribution system. If the sensed current is determined to be above the normal-threshold value and below the overload-threshold value, the method further includes controlling a first group of predetermined relays to actuate to a non-conductive state to power-off a number of associated power outlets. If the sensed current is determined to be above the overload-threshold value, the method further includes controlling a second group of predetermined relays to actuate to a non-conductive state to power-off a number of associated power outlets. The method can further include controlling the plurality of relays to actuate to a non-conductive state in accordance with a predetermined sequence to sequentially power-off the second group of power outlets, which are coupled to the relays; and de-energizing the input power line defined on the power distribution system to power-off the first group of power outlets defined on the power distribution system. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects of this invention, the various features thereof, as well as the invention itself, can be more fully understood from the following description when read together with the accompanying drawings in which: FIG. 1a is an intelligent power strip in accordance with an embodiment of the present invention; FIG. 1b is another view of the intelligent power strip shown in FIG. 1; FIG. 2a is an enlarged view of a portion of the intelligent power strip shown in FIG. 1; FIG. 2b is an enlarged view of another portion of the intelligent power strip shown in FIG. 1; FIG. 3 is a power distribution system which includes the intelligent power strip shown in FIG. 1; FIG. 4 is a schematic block diagram of power management circuitry which is included in the intelligent power strip shown in FIG. 1; and FIG. 5 is a flow chart showing a method of using the power strip shown in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following detailed description of the present invention numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be obvious to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the present invention. In accordance with an embodiment of the present invention, an intelligent power strip is set forth that can provide electrical power and power management to one or more computer systems and their related peripheral devices. The power strip includes internal power management circuitry and external power outlets. The intelligent power strip can operate in conjunction with power management procedures, within the scope of the present invention, to provide a power management system for conventional computer systems. The power management system may be implemented on a general purpose computer system to provide that computer system with automatic and/or user programmable power management features. Referring to FIGS. 1a, 1b, 2a, 2b and 3, in one specific embodiment, the intelligent power strip includes an elongated rectangular housing 12, which has a first end 14 and a second end 16. The housing 12 can further include a plurality of externally accessible AC power outlets 18, through which one or more computers 20 and their related peripherals 22 receive power. The power outlets 18 can be mounted along a longitudinal length of one face of the housing 12. A number of mounting brackets 24 can be coupled to the housing 12 to enable the housing to be mounted to an equipment rack 41 as shown in FIG. 3. The first end 14 of the housing 12 can include a number of apertures 14 which may be adapted to permit power and signal conductors to enter an internal region of the housing 12. The second end 16 of the housing 12 can include a plurality of externally accessible communication ports 26. In an embodiment, a first communication ports 26a is adapted to permit an external control device, such as computer system 20, to communicate with the power management circuitry 50 (FIG. 4) defined in the housing 12. A second communication port 26b, defined on the second end 16 of the housing 12, is adapted to permit the power management circuitry 50 to communicate with one or more external devices. The external devices may be one or more intelligent power strips 10, which can be daisy chained together. In an embodiment, a power distribution system 40 can include a plurality of power strips 10 which may be individually operated or which may be daisy chained together as previously described. The power strips can be mounted in the equipment rack 41. The equipment rack 41 can include a number of slots 42, which are adapted to securely hold a number of pieces of equipment (not shown) thereon. Referring further to FIG. 4, the power management circuitry 50, which is positioned in the interior region of the housing 12 of the power strip 10, includes a current sensor circuit 52. The current sensor circuit 52 receives AC input power over an AC input power line 54 from an AC power source 80 through branch circuit breaker 82. The power outlets 18 defined on the power strip can include a first group of power outlets 18a and a second group of power outlets 18b. The first group of power outlets 118a can be coupled to the current sensor circuit and can be defined as constant power outlets. The first group of power outlets 18a can remain energized as long as power is provided to the power strip 10 by the AC power source 80 over input power line 54. Each outlet, defined in the second group of power outlets 18b, can be coupled to the current sensor circuit via an associated relay 56. The second group of power outlets 18b can remain energized as long as the relay 56 associated with each outlet is actuated to a conductive state. The current sensor circuit 52 is further coupled to an AC to DC power supply 58 which can provide a plurality of DC voltage values to power other components of the power strip 10. The AC to DC power supply 58 can be coupled to an input power source sensor circuit 60 which is further coupled to a micro-controller 62. The input power source sensor circuit 60 is adapted to receive primary DC input power over power line 60a from the AC to DC power supply 58. The input power source sensor circuit 60 is further adapted to receive secondary DC input power from a secondary source 61. The secondary source can include a DC power line 60c provided by the communication-in circuitry 64a, which will be described in further detail below. In an embodiment, the primary and secondary DC input power can include a 24-volt DC input voltage level. The input power source sensor circuit 60 normally operates from the primary DC input power, which is provided by the AC to DC power supply 58. The input power source sensor circuit 60 further provides the primary DC input power to the micro-controller 62 over line 62a. However, in the event of a failure of the AC to DC power supply 58, the secondary DC input power can be provided by the input power source sensor circuit 60 to power the micro-controller 62. In this configuration, the micro-controller 62 can be redundantly powered by either the primary DC input power or the secondary DC input power via the input power source sensor circuit 60. The input power source sensor circuit 60 can further include circuitry to determine if the input power source sensor circuit 60 is providing power to the micro-controller 62 from the primary or secondary DC input power. In the event that the input power source sensor circuit 60 determines that it is providing the secondary DC input power to the micro-controller, the input power source sensor circuit 60 can communicate with the operator, via the communication-in circuit 64a, to notify the operator that the AC to DC supply 58 has failed. In one embodiment, the micro-controller 62, which is incorporated in the power management circuitry 50, is a model XA, PXAG49 KBA, which can be obtained from Philips, Amsterdam, Netherlands. The micro-controller 62 can receive a sense current signal from the current sensor circuit 52 over line 62b, which represents a proportionate level of current that is drawn by the power strip 10 over the input power line 54. The micro-controller is further coupled to the communication-in circuit 64a and the communication-out 64b circuit. The communication-in circuit 64a and the communication-out circuit 64b are respectively coupled to the first 26a and second 26b communication ports, which are defined on the external region of the second end 16 of the housing 12. In an embodiment, the communication-in circuit 64a and the communication-out circuit 64b can each include an RS232 communication device. The RS232 communication devices associated with the communication-in circuit 64a and the communication-out circuit 64b can each bi-directionally communicate with the micro-controller 62 over their respective communication lines Tx1, Rx1 and Tx2, Rx2. The micro-controller 62 is further coupled to an audible alarm 66 and a mute button 68. The audible alarm 66 alerts an operator, via a speaker 13 (FIG. 2b) mounted on the housing 12, of electrical current on the input power line 54 that exceeds a predetermined threshold value. The operator can silence the alarm 66 by actuating the mute button 68. The micro-controller 62 is also coupled to a non-volatile memory 70, such as an electrically-erasable-programmable-read-only-memory (“EEPROM”). The non-volatile memory 70 can store configuration information as well as power management operating instructions. An under-voltage sensor circuit 72 is coupled to the micro-controller 62 and can provide a reset signal to the micro-controller 62 over line 62c. More specifically, the under-voltage sensor circuit 72 is adapted to receive a 5-volt value from the AC to DC supply 58. The under-voltage sensor circuit 72 compares the 5-volt value to a predetermined threshold value. If the 5-volt value falls below the predetermined threshold value a reset signal is provided by the under-voltage sensor circuit 72 to the micro-controller 62 over line 62c. For example, the predetermined under-voltage threshold value can be programmed to 4.6-volts. Thus, if the 5-volt DC voltage provided to the under-voltage sensor circuit 72 by the power supply 58 falls below the under-voltage threshold value of 4.6-volt, a reset signal will be provided to the micro-controller 62 over line 62c. The reset signal can reset the micro-controller 62 or maintain the micro-controller 62 at an idle state until the AC to DC supply 58 provides the under-voltage sensor circuit 72 with a voltage value that exceeds the threshold value or which exceeds the threshold value of 4.6-volts in this example. Maintaining the micro-controller in an idle state, when the 5-volt value provided by the AC to DC power supply is below the threshold, minimizes the micro-controller entering a random logic state. The micro-controller 62 is further coupled to a relay driver circuit 76. The relay driver circuit 76 is coupled to each relay 56 associated with each of the power outlets 18b. Additionally, the relay driver circuit 76 can provide a control signal to each relay 56, which is associated with each power outlet 18b, to power-on and power-off each power outlet 18b. More precisely, each relay 56 can be individually actuated between a conductive state and a non-conductive state for controllably providing power to each power outlet 18b that is associated with each relay 56. Each power outlet 18b can include an LED 15 that can be controlled to illuminate to indicate to an operator that a particular power outlet 18b is powered-on. An over load LED 78 can be coupled to the micro-controller 62. The over-load LED 78 can be controlled to illuminate or flash at a predetermined frequency to indicate the operating status of the intelligent power strip 10 to an operator. In one example, the overload LED 78 can be controlled to illuminate a green light when the current drawn over input power line 54 is under a predetermined normal-threshold value. The overload LED 78 can also be controlled to illuminate a green flashing light when the current drawn over input power line 54 is over the normal-threshold value, but below a predetermined overload-threshold value. The overload LED 78 can be further controlled to illuminate a red light when the current drawn over input power line 54 has exceeded the overload-threshold value. Referring further to FIG. 5, a method of operating the intelligent power strip 100 can include an operator powering-on the first group of power outlets 18a by applying AC power to the input power line 54 at step 110. Immediately after applying AC power to the AC input power line 54, the first group of power outlets 18a can be powered-on to energize one or more computers 20 or peripheral devices 22 coupled therewith. After applying AC power to the power strip 10, the power strip 10 can be initialized at step 120. In initializing the power strip 10 at step 110, the operator can program the power strip 10 with a number of system parameters and operating configurations. The system parameters and operating configurations can include: a normal-threshold value, an overload-threshold value, an under-voltage threshold value, delays related to powering-on and powering-off the second group power outlets 18b and the sequence for which power outlets 18b can be powered-on and powered-off. After initializing the power strip at step 120, the second group of power outlets 18b can be selectively powered-on at step 130. The second group of power outlets 18b can be selectively powered-on, at step 130, in accordance with the operator defined sequence and operator defined delays. Similarly, one or more computers 20 and/or peripheral devices 22, which can be coupled to the second group of power outlets 18b can also be powered-on in accordance with the sequence and delays. After the step of powering-on the second group of outlets at step 130, the method of operating the intelligent power strip further includes sensing current on the power input line 54, at step 140, with the current sense circuit 52. The current values sensed by the current sense circuit 52 are provided to the micro-controller 62 to enable the micro-controller 62 to determine if the normal-threshold value or the overload-threshold value has been exceeded. At step 150, if it is determined that the sensed current on the input power line 54 is below the normal-threshold value, normal operation can continue at step 160. If the micro-controller 62 determines that the current on input power line 62 has exceeded the normal-threshold value at step 150, but is still below the overload-threshold value, as determined at step 170, the micro-controller can provide a control signal over line 76a to instruct the relay driver 76 to actuate one or more relays. At step 180, the relays 56 can be actuated to a non-conductive state to power-off one or more associated power outlets 18b and associated equipment. At step 190, the micro-controller can further control the overload LED 78 to flash a green light to indicate the overload status of the power strip 10. At step 170, if it is determined that the sensed current on the input power line 54 has exceeded the overload-threshold value, the micro-controller 62 can provide another control signal over line 76a to instruct the relay driver 76 to actuate additional relays 56. At step 200, the additional relays 56 can be actuated to a non-conductive state to power-off additional power outlets 18b as well as associated connected loads. In this manner, one or more power outlets 18b can be powered-off depending on the current sensed on the input power line 54 to minimize branch circuit breaker 82 tripping, which can cause all of the power outlets 18 to power-off. At step 210, the micro-controller 62 can turn on the alarm 66 to alert an operator of the overload status of the power strip 10. At step 220, the micro-controller 62 can further illuminate the overload LED 78 to provide a red light to alert an operator of the overload status of the power strip 10. At step 160, an operator can elect to power down the power strip 10. The power strip 10 can be powered down by selectively powering-off the second group of power outlets 18b, at step 230. The second group of power outlets 18b can be controlled to power-off in accordance with the operator defined sequence and operator defined delays. Therefore, the second group of power outlets 18b can be sequentially powered-off to sequentially de-energize the one or more computers 20 or peripheral devices 22 coupled to the second group of power outlets 18b. At step 240, the first group of power outlets 18a can be powered-off immediately after removing power from the AC input power line 54, which consequently de-energizes the one or more computers 20 or peripheral devices 22 coupled to the first group of power outlets 18a. In an embodiment, the operator can further program additional power strip operating parameters such as a maximum current draw on the input power line 54. The maximum current draw value is a percentage of the full load current carrying capacity of power conductors (not shown) defined in the input power line 54. For example, if the input power line includes four copper number 10 American Wire Gauge (“AWG”) conductors with type-THHN insulation, the full load current carrying capacity of the conductors will be approximately 30-Amperes. In this example, the operator can program the maximum current drawn over these conductors to be 66 percent of their full load current carrying capacity or approximately 20-Amperes. As a result, when the power strip 10 is initially energized the second group of power outlets 18b can be sequentially energized, provided the sensed current on input power line 54 does not exceed the percentage of the full load current carrying capacity of the power conductors or 20-Amperes in this example. Programming the maximum current drawn on the input power line 54 can prevent thermal stressing of the conductors and avoid damaging the conductors as well as avoid branch circuit breaker 82 tripping. In other embodiments of the present invention, the power strip 10 can be mounted horizontally in the equipment rack 41 or alternatively, the power strip 10 can be flush mounted on an exterior surface of the equipment rack 41 without departing from the spirit and scope of the present invention. Although not shown, it can be readily understood by those skilled in the art that the power outlets 18 and associated power management circuitry 50 included on the power strip 10 can be adapted for mounting in a portable housing without departing from the spirit and scope of the present invention. For example, the portable housing can include a rectangular, cubical or cylindrically shaped structure that can accommodate the power outlets 18 and power management circuitry 50. In this manner, the principles of the present invention, as described above, can be incorporated into a power distribution system that is easily transportable. Having thus described at least one illustrative embodiment of the invention, various alterations, modifications and improvements will readily occur to those skilled in the art. Such alterations, modifications and improvements are intended to be within the scope and spirit of the invention. Accordingly, the foregoing description is by way of example only and is not intended as limiting. | <SOH> BACKGROUND <EOH>Many electronic and electrical systems, such as computer and home entertainment systems, require that electrical power be applied to components of the system according to a particular sequence to avoid causing undue stress and possible damage to the components. Particularly with computer systems, there are many situations in which it is advantageous to delay activation of peripheral devices until after the parent device is powered up and has attained a quiescent state. A typical situation is that of a personal or business computer system where the activation of peripheral devices including a monitor, disk drives and printers, are delayed until after the computer itself is fully on-line. Upon activation of the parent device and after the parent device reaches a quiescent operating state, power can be applied to the peripheral devices. This sequence of powering up a computer system is especially helpful in eliminating undesirable transient currents and random logic states caused by simultaneous power up of the parent and peripheral devices. For example, in many computer systems, power is first applied to the computer itself before power is applied to the monitor, because the computer supplies the monitor with horizontal and vertical synchronization pulses necessary to prevent the free running of the monitor's horizontal and vertical oscillators. Allowing the oscillators to operate in an unsynchronized condition can result in undue stress to the oscillators and hard failure of the monitor. Similarly, power is applied to the computer before power is applied to the printer. Otherwise, the printer can potentially back-feed power or control signals to the computer and cause the computer to fail to initialize when the computer subsequently receives power. Consequently, the order and timing of the application of power to and removal of power from certain systems needs to be carefully controlled so as to avoid damaging the system components. One solution for providing power to systems similar to that described above includes employing an operator to manually turn on the components. Specifically, the operator can power on the computer itself and pause momentarily to allow sufficient time for the computer to reach a quiescent operating state before providing power to the computer's peripheral devices. This method is generally unsatisfactory, because the time delay interval is difficult to control and duplicate manually, and further, because it may be desirable to ensure that the power up and power down of the system always occur according to a particular sequence. Another solution is to use time delay relays (“TDRs”) to provide a predetermined, fixed time delay between application of power to one component and the next. This method is also unsatisfactory, as well as being very expensive. TDRs are capable only of providing a fixed, or at best, a narrowly adjustable, time delay. Furthermore, the power up delay is typically equal to the power down delay, a condition which may be undesirable in certain cases. Finally, the time delay provided by the TDRs is typically not easy to adjust by an operator. Therefore, a need exists for an intelligent power distribution system that can provide power up and/or power down sequences and delays for equipment, which overcomes limitations and deficiencies of the prior art. | <SOH> SUMMARY OF THE INVENTION <EOH>It is an object of the present invention to provide an intelligent power distribution system and method for using the power distribution system. In embodiments of the present invention, the intelligent power distribution system can manage power consumption to minimize tripping of a branch circuit breaker which provides electrical power to the system. In one aspect of the present invention, a power distribution system can include a plurality of intelligent power strips that can be adapted for mounting in an equipment rack. The power strips can be individually mounted and controlled or the power strips can be daisy chained together to form a scalable power strip which can be unitarily controlled. The equipment rack can have a number of slots that may be adapted to securely hold a number of pieces of equipment thereon. Each intelligent power strip can include a housing that has a first end and a second end. A plurality of power outlets can be mounted on an exterior surface of the housing to provide power to the equipment. An aperture can be formed on the first end of the housing to enable power and signal conductors to access an interior region of the housing. A first communication port and a second communication port can be defined on the second end of the housing. The first communication port can include a communication-in circuit that enables bi-directional communication with the power strip and the second communication port can include a communication-out circuit that enables the power strip to be coupled to a second power strip. The intelligent power strip can further include a power management circuit which is defined in the interior region of the housing. The power management circuit can include a current sensor circuit that may be adapted to receive alternating current (“AC”) input power over an AC input power line. The current sensor circuit can be coupled to the power outlets as well as to an AC to direct current (“DC”) power supply. The AC to DC power supply receives and processes AC power from the current sensor circuit to generate a plurality of DC voltage values. The micro-controller can be coupled to the power supply and can receive one or more voltage values from the power supply. The micro-controller may be further coupled to a relay driver. The relay driver can receive control signals from the micro-controller to control a plurality of relays coupled to the relay driver. The relays can be coupled to the power outlets defined on the housing of the power strip. The relays can be controlled to a conductive state to power-on the power outlets and the relays can be controlled to a non-conductive state to power-off the power outlets. The power outlets defined on the power strip can include a first group of power outlets and a second group of power outlets. The first group of power outlets can be coupled to the sensor circuit and the second group of power outlets can be coupled to the sensor circuit via the relays. The second group of power outlets can each include a light-emitting-diode (“LED”) that can be controlled to illuminate to indicate that each power outlet is powered-on. The power management circuit can further include an input power source sensor circuit. The input power source sensor circuit can be coupled intermediate the power supply and the micro-controller. The input power source sensor circuit can receive DC input power from the power supply that is hereinafter defined as primary DC input power, which can be provided to the micro-controller. The input power source sensor circuit can further receive secondary DC input power from a secondary power source. The secondary power source can be provided by the communication-in circuit and can provide a redundant power source for the micro-controller. In the event that the primary DC input power provided by the power supply fails or is unavailable, the input power source sensor circuit can provide the secondary DC input power to the micro-controller. The micro-controller can be further coupled to an under voltage sensor. The under voltage sensor can be adapted to receive a predetermined voltage value from the power supply. The under voltage sensor can be responsive to the predetermined voltage value falling below a predetermined threshold value by providing a reset signal to the micro-controller. The predetermined threshold value can be defined by a user of the intelligent power distribution system. A non-volatile memory device can also be coupled to micro-controller to enable the micro-controller to store initialization and configuration information as well as other operating parameters. The micro-controller can also be coupled to an audible alarm that can alert an operator that current on the input power line has exceeded a predetermined threshold value. A mute button coupled to the micro-controller can be actuated to silence the audible alarm. An overload LED, which is coupled to the micro-controller, can be controlled to illuminate with a predetermined frequency to indicate an overload status of the input power line. In another aspect of the present invention, a power distribution method includes energizing an input power line to power-up a first group of power outlets on a power distribution system; and controlling a plurality of relays to actuate to a conductive state in accordance with a predetermined sequence and predetermined delay to sequentially power-on a second group of power outlets defined on the power distribution system. Powering-on the second group of power outlets further includes illuminating a light-emitting-diode associated with each power outlet, defined in the second group, to indicate a powered-on status of the second group of power outlets. Initializing the power distribution system can include programming a normal-threshold value into the power distribution system; programming an overload-threshold value into the power distribution system; programming an under-voltage threshold value into the power distribution system; programming delays into the power distribution system, the delays can be related to powering-on and powering-off power outlets defined in the second group; and programming the sequence for which power outlets can be powered-on and powered-off. The method can further include sensing current on the input power line; providing the sensed current to a micro-controller; and determining if the sensed current is below the normal-threshold value. If the sensed current is determined to be below the normal-threshold value then the method further includes indicating a normal operating status of the power distribution system. The method can further include determining if the sensed current is above the normal-threshold value; and determining if the sensed current is below the overload-threshold value. If the sensed current is determined to be above the normal-threshold value and below the overload-threshold value, the method further includes indicating a high current status of the power distribution system. The method can further include determining if the sensed current is above the overload-threshold value. If the sensed current is determined to be above the overload-threshold value, the method further includes indicating an alarm status of the power distribution system. If the sensed current is determined to be above the normal-threshold value and below the overload-threshold value, the method further includes controlling a first group of predetermined relays to actuate to a non-conductive state to power-off a number of associated power outlets. If the sensed current is determined to be above the overload-threshold value, the method further includes controlling a second group of predetermined relays to actuate to a non-conductive state to power-off a number of associated power outlets. The method can further include controlling the plurality of relays to actuate to a non-conductive state in accordance with a predetermined sequence to sequentially power-off the second group of power outlets, which are coupled to the relays; and de-energizing the input power line defined on the power distribution system to power-off the first group of power outlets defined on the power distribution system. | 20040409 | 20061128 | 20050310 | 63872.0 | 1 | DEBERADINIS, ROBERT L | INTELLIGENT POWER DISTRIBUTION SYSTEM | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,821,753 | ACCEPTED | Lightweight, structurally integral, and strong composite rack shelving | Lightweight, structurally integral, and strong composite rack shelving that includes a shelf. The shelf includes a honeycomb core sandwiched between an upper skin and a lower skin so as to form a composite structure that is lightweight and strong. The shelf has a plurality of through bores that pass vertically therethrough which allow flames under the shelf to pass upwardly therethrough instead of sidewardly therealong and to pass an extinguishant thereabove to flow downwardly therethrough for extinguishing the flames thereunder. | 1. Lightweight, structurally integral, and strong composite rack shelving, comprising: a shelf; wherein said shelf comprises a honeycomb core; wherein said shelf comprises an upper skin; wherein said shelf comprises a lower skin; wherein said honeycomb core of said shelf is sandwiched between said upper skin of said shelf and said lower skin of said shelf so as to form a composite structure; wherein said composite structure of said shelf is lightweight; wherein said composite structure of said shelf is strong; wherein said shelf has a plurality of through bores; wherein said plurality of through bores pass vertically through said shelf; and wherein said plurality of through bores through said shelf allow flames under said shelf to pass upwardly therethrough instead of sidewardly therealong whereby an extinguishant thereabove can pass downwardly therethrough for extinguishing flames thereunder. 2. The shelving as defined in claim 1, wherein said shelf has a surface area; and wherein said plurality of through bores through said shelf occupy approximately 50% of said surface area of said shelf. 3. The shelving as defined in claim 1; further comprising a border; wherein said shelf has a periphery; and wherein said border closes off said periphery of said shelf. 4. The shelving as defined in claim 3, wherein said honeycomb core of said shelf comprises walls; and wherein said walls of said honeycomb core of said shelf define cells. 5. The shelving as defined in claim 4, wherein said border is a tape that is affixed to any wall of said honeycomb core of said shelf that it comes in contact with, especially any that defines an open cell of said honeycomb core of said shelf located at said periphery of said shelf so as to maintain structural integrity of said shelf by closing off any open cell of said honeycomb core of said shelf located at said periphery of said shelf and form a structurally integral unit with said shelf, and which folds over to be affixed to said upper skin of said shelf and said lower skin of said shelf. 6. The shelving as defined in claim 4; further comprising inserts; and wherein said inserts line said plurality of through bores through said shelf, respectively. 7. The shelving as defined in claim 6, wherein said inserts are tapes that are affixed to any wall of said honeycomb core of said shelf that they come in contact with, especially any that defines an open cell of said honeycomb core of said shelf caused by a through bore through said shelf so as to maintain structural integrity of said shelf by closing off any open cell of said honeycomb core of said shelf caused by a through bore through said shelf and form a structurally integral unit with said shelf, and which fold over to be affixed to said upper skin of said shelf and said lower skin of said shelf. 8. An improved rack system of the type having columns, beams interconnected to the columns, and shelving supported by the beams, said improvement comprising: a) the shelving being lightweight; b) the shelving being structurally integral; c) the shelving being strong; d) the shelving comprising a shelf; e) said shelf comprising a honeycomb core; f) said shelf comprising an upper skin; g) said shelf comprising a lower skin; h) said honeycomb core of said shelf being sandwiched between said upper skin of said shelf and said lower skin of said shelf so as to form a composite structure; i) said composite structure of said shelf being lightweight; j) said composite structure of said shelf being strong; k) said shelf having a plurality of through bores; l) said plurality of through bores passing vertically through said shelf; and m) said plurality of through bores through said shelf being for allowing flames under said shelf to pass upwardly therethrough instead of sidewardly therealong and an extinguishant thereabove to pass downwardly therethrough and extinguish the flames thereunder. 9. The improved rack system as defined in claim 8, wherein said shelf has a surface area; and wherein said improvement comprises said plurality of through bores through said shelf occupying 50% of said surface area of said shelf. 10. The improved rack system as defined in claim 8, wherein said improvement comprises: a) said shelf having a periphery; b) the shelving comprising a border; and c) said border closing off said periphery of said shelf. 11. The improved rack system as defined in claim 10, wherein said improvement comprises: a) said honeycomb core of said shelf comprising walls; and b) said walls of said honeycomb core of said shelf defining cells. 12. The improved rack system as defined in claim 11, wherein said improvement comprises said border being a tape that is affixed to any wall of said honeycomb core of said shelf that it comes in contact with, especially any that defines an open cell of said honeycomb core of said shelf located at the periphery of said shelf so as to maintain structural integrity of said shelf by closing off any open cell of said honeycomb core of said shelf located at the periphery of said shelf and form a structurally integral unit with said shelf, and which is folded over to be affixed to said upper skin of said shelf and said lower skin of said shelf. 13. The improved rack system as defined in claim 11, wherein said improvement comprises: a) the shelving comprising inserts; and b) said inserts lining said plurality of through bores through said shelf, respectively. 14. The improved rack system as defined in claim 13, wherein said improvement comprises said inserts being tapes that are affixed to any wall of said honeycomb core of said shelf that they come in contact with, especially any that defines an open cell of said honeycomb core of said shelf caused by a through bore through said shelf so as to maintain structural integrity of said shelf by closing off any open cell of said honeycomb core of said shelf caused by a through bore through said shelf and form a structurally integral unit with said shelf, and which are folded over to be affixed to said upper skin of said shelf and said lower skin of said shelf. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to rack shelving. More particularly, it relates to lightweight, structurally integral, strong composite rack shelving. 2. Description of the Prior Art Numerous innovations for rack shelving have been provided in the prior art. Even though they frequently are suitable for specific purposes which they address, they each differ in structure and/or operation and/or purpose from the present invention and they therefore are not suitable for the purposes of the present invention. A typical prior art rack system 20 can be seen in FIGS. 1 and 2, which are, respectively, a diagrammatic perspective view of a typical prior art rack system illustrating columns, beams, and a shelf thereof in use, and an enlarged diagrammatic top plan view of the area generally enclosed by a dotted curve identified by ARROW 2 in FIG. 1 illustrating a spacer utilized for the shelf shown in FIG. 1, and as such, will be discussed with reference thereto. The typical prior art rack system 20 comprises columns 22, beams 24, and a shelf 26. The columns 22 are vertical support members which interconnect with the beams 24 which are horizontal support members. Each column 22 has rows of slots 28 which are vertically extending and each beam 24 has pins 30 which are spaced apart from each other and which insert into the slots 28 in the column 22. Each beam 24 further has a step 32 extending therealong which has the shelf 26 rest thereon. The beam 24 is connected to the column 22 by first inserting the pins 30 of the beam 24 into upper portions 34 of the slots 28 in the column 22 and then sliding the pins 30 of the beam 24 downwardly into lower portions 36 of the slots 28 in the column 22. When the beam 24 is so connected, a portion of the pin 30 of the beam 24 projects beyond an associated slot 28 in the column 22 to secure the beam 24 from axially disengaging from the column 22, i.e., the beam 24 can only be disconnected by reversing the connection sequence. Once the beam 24 is connected to the column 22 by inserting the pins 30 of the beam 24 into the upper portions 34 of the slots 28 in the column 22 and sliding them downwardly into the lower portions 36 of the slots 28 in the column 22, the beam 24 will remain secured to the column 22 so long as there is a downward force on the pins 30 of the beam 24. The shelf 26 comprises a plurality of boards 38, which are free from each other, and which are wood. Each board 38 of the shelf 26 extends transversely, and has a pair of ends 40 which rest on the steps 32 of the beams 24, respectively. The plurality of boards 38 of the shelf 26 are spaced-apart from each other by spacers 42. Each spacer 42 is bent from a strip of metal into a body 44 and a pair of wings 46. The body 44 of the spacer 42 generally is U-shaped and has terminal ends 48 from which the pair of wings 46 of the spacer 42 extend perpendicularly outwardly. The spacer 42 rests on the step 32 of the beam 24 with the body 44 of the spacer 42 spacing apart a pair of adjacent boards 38 of the shelf 26. The spacer 42 is maintained on the step 32 of the beam 24 only by the pair of wings 46 of the spacer 42 being sandwiched between adjacent ends 40 of the pair of adjacent boards 38 of the shelf 26 and the beam 24. Each board 38 therefore must have a specific width, i.e., a width extending from the body 44 of one spacer 42 to the body 44 of an adjacent spacer 44. Thus, the shelf 26 comprises a plurality of separate, non-mechanically connected parts, namely, the plurality of boards 38 and the spacers 42, and as a result thereof, afford little structural integrity for the shelf 26. Further, the shelf 26 is heavy as a result of the plurality of boards 38 being wood. Thus, there exists a need for composite rack shelving which affords structural integrity by having no non-mechanically connected parts, is light weight and strong, and allows flames thereunder to pass upwardly therethrough instead of sidewardly therealong and an extinguishant thereabove to pass downwardly therethrough and extinguish the flames thereunder. SUMMARY OF THE INVENTION ACCORDINGLY, AN OBJECT of the present invention is to provide lightweight, structurally integral, and strong composite rack shelving that avoids disadvantages of the prior art. ANOTHER OBJECT of the present invention is to provide lightweight, structurally integral, and strong composite rack shelving that is simple to use. BRIEFLY STATED, STILL ANOTHER OBJECT of the present invention is to provide lightweight, structurally integral, and strong composite rack shelving that includes a shelf. The shelf comprises a honeycomb core sandwiched between an upper skin and a lower skin so as to form a composite structure that is lightweight and strong. The shelf has a plurality of through bores that pass vertically therethrough and allow flames under the shelf to pass upwardly therethrough instead of sidewardly therealong and allow an extinguishant thereabove to pass downwardly therethrough to extinguish flames thereunder. Novel features which are considered characteristic of the present invention are identified in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood a description of the invention which follows, read in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The figures of the drawings are briefly described as follows: FIG. 1 is a diagrammatic perspective view of a typical prior art rack system illustrating columns, beams, and a shelf thereof in use; FIG. 2 is an enlarged diagrammatic top plan view of the area generally enclosed by the dotted curve identified by ARROW 2 in FIG. 1 illustrating a spacer utilized for the shelf shown in FIG. 1; FIG. 3 is a diagrammatic perspective view of a rack system illustrating the prior art columns, the prior art beams, and the composite shelf of the present invention in use, with the composite shelf being lightweight, structurally integral, and strong; FIG. 4 is an enlarged diagrammatic perspective view of the area generally enclosed by the dotted curve identified by ARROW 4 in FIG. 3 illustrating the lightweight, structurally integral, and strong composite rack shelving of the present invention shown in FIG. 3; FIG. 5 is a diagrammatic top plan view taken generally in the direction of ARROW 5 in FIG. 4 illustrating the lightweight, structurally integral, and strong composite rack shelving of the present invention shown in FIG. 4 with a portion of the upper skin thereof removed to reveal a portion of the honeycomb core thereof at an enlarged scale; FIG. 6 is a diagrammatic cross sectional view taken along line 6-6 in FIG. 5; and FIG. 7 is a diagrammatic cross sectional view taken along line 7-7 in FIG. 5. LIST OF REFERENCE NUMERALS UTILIZED IN THE DRAWINGS Prior Art 20 typical prior art rack system 22 columns 24 beams 26 shelf 28 slots in each of the columns 22 30 pins in each of the beams 24 32 step of each of the beams 24 34 upper portions of slots 28 in each of the 36 columns 22 36 lower portions of slots 28 in each of the columns 22 38 plurality of boards of shelf 26 40 pair of ends of each of the boards 38 of the shelf 26 42 spacers 44 body of each of the spacers 42 46 pair of wings of each of the spacers 42 48 terminal ends of body 44 of each of the spacers 42 Present Invention 50 lightweight, structurally integral, and strong composite rack shelving of present invention 52 flames 54 extinguishant 56 shelf 58 plurality of through bores through shelf 56 for allowing flames 52 thereunder to pass upwardly therethrough instead of sidewardly therealong and extinguishant 54 thereabove to pass downwardly therethrough and extinguish flames 52 thereunder. 60 honeycomb core of shelf 56 62 upper skin of shelf 56 64 lower skin of shelf 56 66 composite structure of shelf 56 68 walls of honeycomb core 60 of shelf 56 70 cells of honeycomb core 60 of shelf 56 72 periphery of shelf 56 74 border 80 inserts DETAILED DESCRIPTION OF THE INVENTION Referring now to the figures, in which like numerals indicate like parts, and particularly to FIG. 3, which is a diagrammatic perspective view of a rack system illustrating prior art columns, prior art beams, and a composite shelf of the present invention in use, with the composite shelf being lightweight, structurally integral, and strong, the composite rack shelving of the present invention is shown generally at 50. The configuration of the composite rack shelving 50 can best be seen in FIGS. 3-7, which are, respectively, again a diagrammatic perspective view of a rack system illustrating the prior art columns, the prior art beams, and the composite shelf of the present invention in use, with the composite shelf being lightweight, structurally integral, and strong, an enlarged diagrammatic perspective view of the area generally enclosed by the dotted curve identified by ARROW 4 in FIG. 3 illustrating the composite rack shelving of the present invention shown in FIG. 3, a diagrammatic top plan view taken generally in the direction of ARROW 5 in FIG. 4 illustrating the composite rack shelving of the present invention shown in FIG. 4 with a portion of the upper skin thereof removed to reveal a portion of the honeycomb core thereof, a diagrammatic cross sectional view taken along line 6-6 in FIG. 5, and a diagrammatic cross sectional view taken along line 7-7 in FIG. 5, and as such, will be discussed with reference thereto. The composite rack shelving 50 comprises a shelf 56. The shelf 56 comprises a honeycomb core 60, an upper skin 62, and a lower skin 64. The honeycomb core 60 of the shelf 56 is sandwiched between the upper skin 62 of the shelf 56 and the lower skin 64 of the shelf 56 so as to form a composite structure 66 that is lightweight and strong. The shelf 56 has a plurality of through bores 58 that pass vertically therethrough. The plurality of through bores 58 through the shelf 56 are for allowing flames 52 thereunder to pass upwardly therethrough instead of sidewardly therealong and an extinguishant 54 thereabove to pass downwardly therethrough and extinguish the flames 52 thereunder. The shelf 56 has a surface area, and the plurality of through bores 58 through the shelf 56 occupy 50% of the surface area of the shelf 56. The honeycomb core 60 of the shelf 56 comprises walls 68 that define cells 70. The shelf 56 further has a periphery 72, and the composite rack shelving 50 further comprises a border 74. The border 74 closes off the periphery 72 of the shelf 56, and is a tape that is affixed to any wall 68 of the honeycomb core 60 of the shelf 56 that it comes in contact with, especially any that defines an open cell 70 of the honeycomb core 60 of the shelf 56 located at the periphery 72 of the shelf 56 so as to maintain structural integrity of the shelf 56 by closing off any open cell 70 of the honeycomb core 60 of the shelf 56 located at the periphery 72 of the shelf 56 and form a structurally integral unit with the shelf, and which folds over to be affixed to the upper skin 62 of the shelf 56 and the lower skin 64 of the shelf 56. The composite rack shelving 50 further comprises inserts 80. The inserts 80 line the plurality of through bores 58 through the shelf 56, respectively, and are tapes that are affixed to any wall 68 of the honeycomb core 60 of the shelf 56 that they come in contact with, especially any that defines an open cell 70 of the honeycomb core 60 of the shelf 56 caused by a through bore 58 through the shelf 56 so as to maintain structural integrity of the shelf 56 by closing off any open cell 70 of the honeycomb core 60 of the shelf 56 caused by a through bore 58 through the shelf 56 and form a structurally integral unit with the shelf 56, and which fold over to be affixed to the upper skin 62 of the shelf 56 and the lower skin 64 of the shelf 56. Although the invention has been illustrated and described as embodied in a lightweight, structurally integral, and strong composite rack shelving, it is not limited to the details shown, since it will be understood that various omissions, modifications, substitutions, and changes in the forms and details of the device illustrated and its operation can be made by those skilled in the art without departing from the spirit of the present invention. Without further analysis the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that from the standpoint of prior art fairly constitute characteristics of the generic or specific aspects of the present invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to rack shelving. More particularly, it relates to lightweight, structurally integral, strong composite rack shelving. 2. Description of the Prior Art Numerous innovations for rack shelving have been provided in the prior art. Even though they frequently are suitable for specific purposes which they address, they each differ in structure and/or operation and/or purpose from the present invention and they therefore are not suitable for the purposes of the present invention. A typical prior art rack system 20 can be seen in FIGS. 1 and 2 , which are, respectively, a diagrammatic perspective view of a typical prior art rack system illustrating columns, beams, and a shelf thereof in use, and an enlarged diagrammatic top plan view of the area generally enclosed by a dotted curve identified by ARROW 2 in FIG. 1 illustrating a spacer utilized for the shelf shown in FIG. 1 , and as such, will be discussed with reference thereto. The typical prior art rack system 20 comprises columns 22 , beams 24 , and a shelf 26 . The columns 22 are vertical support members which interconnect with the beams 24 which are horizontal support members. Each column 22 has rows of slots 28 which are vertically extending and each beam 24 has pins 30 which are spaced apart from each other and which insert into the slots 28 in the column 22 . Each beam 24 further has a step 32 extending therealong which has the shelf 26 rest thereon. The beam 24 is connected to the column 22 by first inserting the pins 30 of the beam 24 into upper portions 34 of the slots 28 in the column 22 and then sliding the pins 30 of the beam 24 downwardly into lower portions 36 of the slots 28 in the column 22 . When the beam 24 is so connected, a portion of the pin 30 of the beam 24 projects beyond an associated slot 28 in the column 22 to secure the beam 24 from axially disengaging from the column 22 , i.e., the beam 24 can only be disconnected by reversing the connection sequence. Once the beam 24 is connected to the column 22 by inserting the pins 30 of the beam 24 into the upper portions 34 of the slots 28 in the column 22 and sliding them downwardly into the lower portions 36 of the slots 28 in the column 22 , the beam 24 will remain secured to the column 22 so long as there is a downward force on the pins 30 of the beam 24 . The shelf 26 comprises a plurality of boards 38 , which are free from each other, and which are wood. Each board 38 of the shelf 26 extends transversely, and has a pair of ends 40 which rest on the steps 32 of the beams 24 , respectively. The plurality of boards 38 of the shelf 26 are spaced-apart from each other by spacers 42 . Each spacer 42 is bent from a strip of metal into a body 44 and a pair of wings 46 . The body 44 of the spacer 42 generally is U-shaped and has terminal ends 48 from which the pair of wings 46 of the spacer 42 extend perpendicularly outwardly. The spacer 42 rests on the step 32 of the beam 24 with the body 44 of the spacer 42 spacing apart a pair of adjacent boards 38 of the shelf 26 . The spacer 42 is maintained on the step 32 of the beam 24 only by the pair of wings 46 of the spacer 42 being sandwiched between adjacent ends 40 of the pair of adjacent boards 38 of the shelf 26 and the beam 24 . Each board 38 therefore must have a specific width, i.e., a width extending from the body 44 of one spacer 42 to the body 44 of an adjacent spacer 44 . Thus, the shelf 26 comprises a plurality of separate, non-mechanically connected parts, namely, the plurality of boards 38 and the spacers 42 , and as a result thereof, afford little structural integrity for the shelf 26 . Further, the shelf 26 is heavy as a result of the plurality of boards 38 being wood. Thus, there exists a need for composite rack shelving which affords structural integrity by having no non-mechanically connected parts, is light weight and strong, and allows flames thereunder to pass upwardly therethrough instead of sidewardly therealong and an extinguishant thereabove to pass downwardly therethrough and extinguish the flames thereunder. | <SOH> SUMMARY OF THE INVENTION <EOH>ACCORDINGLY, AN OBJECT of the present invention is to provide lightweight, structurally integral, and strong composite rack shelving that avoids disadvantages of the prior art. ANOTHER OBJECT of the present invention is to provide lightweight, structurally integral, and strong composite rack shelving that is simple to use. BRIEFLY STATED, STILL ANOTHER OBJECT of the present invention is to provide lightweight, structurally integral, and strong composite rack shelving that includes a shelf. The shelf comprises a honeycomb core sandwiched between an upper skin and a lower skin so as to form a composite structure that is lightweight and strong. The shelf has a plurality of through bores that pass vertically therethrough and allow flames under the shelf to pass upwardly therethrough instead of sidewardly therealong and allow an extinguishant thereabove to pass downwardly therethrough to extinguish flames thereunder. Novel features which are considered characteristic of the present invention are identified in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood a description of the invention which follows, read in connection with the accompanying drawings. | 20040409 | 20060606 | 20051013 | 93770.0 | 0 | NEWTON, JARED W | LIGHTWEIGHT, STRUCTURALLY INTEGRAL, AND STRONG COMPOSITE RACK SHELVING | SMALL | 0 | ACCEPTED | 2,004 |
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10,821,777 | ACCEPTED | Method of RNA cleavage and recombination | A method of cleaving a target RNA molecule is disclosed. In one embodiment the method comprises the step of exposing the target molecule to an eukaryotic tRNA splicing endonuclease, wherein the target molecule is in the bulge-helix-bulge conformation, wherein cleavage occurs within the bulge-helix-bulge and cleavage products are generated, and wherein the target molecule does not comprise a tRNA structure. | 1. A method of cleaving a target RNA molecule comprising the step of exposing the target molecule to an eukaryotic tRNA splicing endonuclease, wherein the target molecule is in the bulge-helix-bulge conformation, wherein cleavage occurs within the bulge-helix-bulge and cleavage products are generated, and wherein the target molecule does not comprise a tRNA structure. 2. The method of claim 1 wherein the bulge-helix-bulge conformation is obtained by hybridizing the target RNA with an oligonucleotide designed to form a bulge-helix-bulge conformation. 3. The method of claim 1 wherein the bulge-helix-bulge conformation is obtained by hybridizing the target RNA with a second RNA wherein the hybridized target RNA and second RNA form a bulge-helix-bulge conformation. 4. The method of claim 1 wherein the target molecule is an mRNA molecule. 5. The method of claim 2 wherein the oligonucleotide comprises an RNA molecule. 6. The method of claim 2 wherein the oligonucleotide comprises a DNA molecule. 7. The method of claim 2 wherein the oligonucleotide comprises at least one nucleotide that is not a ribonucleotide. 8. The method of claim 2 wherein the oligonucleotide is between 58 and 62 nucleotides. 9. The method of claim 1 wherein the cleavage is within a cell. 10. The method of claim 1 wherein the cleavage is in vitro. 11. The method of claim 1 wherein the cleavage is in vivo. 12. A method of cleaving a target RNA molecule comprising the step of exposing the target molecule in a cell to heterologous archeael tRNA splicing endonuclease, wherein the target molecule is in the bulge-helix-bulge conformation, wherein cleavage occurs between the second and third nucleotides at the bulges and cleavage products are generated, and wherein the target molecule does not comprise a tRNA structure. 13. The method of claim 12 wherein the bulge-helix-bulge conformation is created by two mRNA molecules, wherein the two mRNA molecules are the target RNA molecule and a second RNA molecule. 14. The method of claim 12 additionally comprising the step of ligation of cleavage products from the target RNA and the second RNA, wherein a fusion RNA is formed comprising at least one cleavage product from the first target RNA molecule and at least one cleavage product from the second target RNA molecule. 15. The method of claim 12 wherein the cell is selected from the group consisting of mammalian, plant and eubacteria. 16. The method of claim 15 wherein the cell is mammalian. 17. The method of claim 12 wherein the cell is a eukaryotic cell. 18. A method of recombining a target RNA molecule with an exogenous RNA molecule comprising the step of exposing the target RNA molecule and the exogenous RNA molecule to a ligase, wherein the target RNA molecule is in the bulge-helix-bulge conformation, wherein the target RNA has been cleaved within the bulge-helix-bulge, and wherein the target RNA molecule and the exogenous RNA molecule recombine across the bulge-helix-bulge. 19. The method of claim 18 wherein the cell is selected from the group consisting of mammalian, plant and eubacteria. 20. The method of claim 19 wherein the cell is mammalian. 21. The method of claim 19 wherein the cell is a eukaryotic cell. 22. A transgenic animal comprising a gene encoding an archaeal tRNA endonuclease. 23. The transgenic animal of claim 22, wherein the animal is a mouse. | CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to provisional patent application Ser. No. 60/462,624, filed Apr. 14, 2003, and is a continuation-in-part of U.S. Ser. No. 10/296,574, filed Jan. 7, 2003, which is a § 371 of PCT/IB01/01189, which claims priority to Ser. No. 60/208,432, filed on May 31, 2000. All applications listed above are incorporated herein by reference. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT BACKGROUND OF THE INVENTION Accuracy in tRNA splicing is essential for the formation of functional tRNAs and, hence for gene expression. In Bacteria, tRNA introns are self-splicing group I introns and the splicing mechanism is autocatalytic. In Eukarya, tRNA introns are small and invariably interrupt the anticodon loop one base 3′ to the anticodon. In Archaea, the introns are also small and often reside in the same location as eukaryal tRNA introns. In both Eukaryotes and Archaea, the specificity for recognition of the pre-tRNA resides in the endonucleases. These enzymes remove the intron by making two independent endonucleotytic cleavages. The archaeal enzyme acts without any reference to the mature domain (mature-domain independent mode, MDI) but instead recognizes a structure, the bulge-helix-bulge (BHB) motif, that defines the intron-exon boundaries. The eukaryal enzyme normally acts in a mature-domain dependent mode (MDD); the enzyme recognizes a tripartite set of RNA elements. One subset of recognition elements is localized in the mature domain, while two other subsets are localized at the exon-intron boundaries. A pivotal role is played by a base-pair located near the site of 3′ cleavage, the so-called anticodon-intron pair (A-I pair). A purine is strongly preferred at the position preceding the 5′ cleavage site. The primary and secondary structures at the exon-intron junctions of the archaeal and eukaryal pre-tRNAs do not show evident similarities, with the exception of the three-nucleotide bulged structure, closed by the A-I pair and containing the 3′ cleavage site, that resembles half of the BHB. The endonuclease are evolutionarily related, but their substrate recognition properties appear drastically different. It has previously been shown, however, that the Xenopus and the yeast endonucleases retain the ability to operate in the MDI mode. BRIEF SUMMARY OF THE INVENTION In one embodiment, the present invention is a method of cleaving a target RNA molecule comprising the step of exposing in vitro or in vivo the target molecule to an eukaryotic tRNA splicing endonuclease, wherein the target molecule is in the bulge-helix-bulge conformation, wherein cleavage occurs within the bulge-helix-bulge and cleavage products are generated, and wherein the target molecule does not comprise a tNRA structure. In a preferred embodiment, the bulge-helix-bulge conformation is obtained by hybidizing the target RNA with an oligonucleotide designed to form a bulge-helix-bulge conformation. In another preferred embodiment, the bulge-helix-bulge conformation is obtained by hybridizing the target RNA with a second RNA wherein the hybridized target RNA and second RNA form a bulge-helix-bulge conformation. In other embodiments, the target molecule is an mRNA molecule and the oligonucleotide comprises either an RNA molecule, a DNA molecule or a molecule wherein at least one nucleotide is not a ribonucleotide. In another embodiment, the present invention is a method of cleaving a target RNA molecule comprising the step of exposing the target molecule in a cell to heterologous archeael tRNA splicing endonuclease, wherein the target molecule is in the bulge-helix-bulge conformation, wherein cleavage occurs between the second and third nucleotides at the bulges and cleavage products are generated, and wherein the target molecule does not comprise a tRNA structure. Preferably, the bulge-helix-bulge conformation is created by two mRNA molecules, wherein the two mRNA molecules are the target RNA molecule and a second RNA molecule and additionally comprises the step of ligation of cleavage products from the target RNA and the second RNA, wherein a fusion RNA is formed comprising at least one cleavage product from the first target RNA molecule and at least one cleavage product from the second target RNA molecule. This invention is also a method for recombining a target RNA molecule that is in the bulge-helix-bulge (BHB) conformation with an exogenous, or targeting, RNA molecule. As described above, the target RNA molecule has been shown to be cleaved within the bulge-helix-bulge. When the cleaved target RNA molecule and the exogenous RNA molecule are exposed to an appropriate ligase, RNA chimeras form, recombining the target RNA molecule and the exogenous RNA molecule across the bulge-helix-bulge. The method of the present invention can be used for recombining RNA molecules that can be used for altering RNA function. The recombination may be used to destroy RNA function, modify RNA, or even restore RNA function. In another embodiment, the endonuclease, preferably the tRNA endonuclease of the archeobacterium Metahnococcus Jannaschii (MJ), when expressed in an eucaryotic organism can be used to modulate gene expression at the post-transcriptional level. The endonuclease recognizes and splices RNA molecules when the latter have Bulge-Helix-Bulge (BHB) structures. Since the ends that the endonuclease creates are ligated by an endogenous RNA ligase, it is possible to activate, inactivate and fuse RNA molecules. In another embodiment, the invention is a line of transgenic mice that expresses a heterologous tRNA endonuclease in a manner that is constitutive in various tissues. Other features, objects and advantages of the present invention will be apparent to one of skill in the art after review of the specification and claims. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING FIG. 1A depicts the A-1 interaction. FIG. 1B depicts a substrate cleaved in both the mature-domain dependent and the mature-domain independent modes. FIG. 2A shows the Xenopus endonuclease can cleave in vivo in the mature-domain independent mode. FIG. 2B shows that the yeast endonuclease mutant sen2-3 cleaves pre-tRNAArcheuka at both sites. FIG. 2C is a comparison of models of enzyme-substrate interaction. FIG. 3 depicts cleavage of a non-tRNA molecule by the Xenopus endonuclease. FIG. 4 is a diagram of BHB-mediated trans-splicing. FIG. 5 describes a scheme of BHB (bulge-helix-bulge) insertions in the GFP mRNAs. The upper and lower parts of the figure show the structure of the GFPof and the GFP-BHB genes, as well as the BHB position. In the middle, the different BHB substrates are detailed. The BHB and the BHB-stop are processed by the MJ-endoribonuclease whereas the BHB+3 is MJ-endoribonuclease insensitive. Intronic ribonucleotides are underlined, stop codons blocking all reading frames are in bold face and the base-pair insertion disrupting the canonical BHB structure is boxed in green. FIG. 6 depicts direct GFP and Hoechst fluorescence of NIH3T3 transiently transfected with different plasmids as indicated in the figure. Transient transfections were performed with (a) 0.5 μg pEGFP-N3 plus 1.5 μg pMJ; (b) 0.5 μg pGFP of plus 1.5 μg of pMJ; (c) 0.5 μg pGFPof plus 1.5 μg put-MJ; (d) 0.5 μg pGFP of +3 plus 1.5 μg pMJ. FIG. 7 depicts splicing analysis of mRNAs deriving from NIH3T3 cells transfected with pMJ or put-MJ plasmids, and pGFP of, pGFPof+3 and pGFPof-STOP target constructs. FIG. 7A mRNA structure of pGFPof, pGFPof+3 and pGFPof-STOP target constructs and the PCR primers position. FIG. 7B RT-PCR analysis of different GFP mRNA in the presence or absence of functional MJ enzyme. NIH3T3 were transiently transfected with different plasmids as indicated in the figure. A constant 1:3 molar ration between plasmids coding for target tRNAs and for MJ-endoribonuclease was used. FIG. 8 is a sequence analysis of RT-PCR products derived from NIH3T3 cells transiently transfected with pGFPof and pMJ plasmids. Sequences were performed using RT-PCR products eluted from a gel. In the middle, the arrows indicate the intron-flanking nucleotides. FIG. 9 is a splicing analysis on mRNAs derived from NIH3T3 cells transfected with pMJ or put-MJ plasmids, and pGFP-BHB or pGFP-BHB target constructs. FIG. 9A: mRNA structure of pGFP-BHB+3 target constructs and the PCR primers position. FIG. 9B: RT-PCR analysis of different GFP mRNA in the presence or absence of functional MJ enzyme. NIH3T3 were transiently transfected with different plasmids as indicated in the figure. A constant 1:3 molar ratio between plasmids coding for target TRNAS and for MJ-endoribonuclease was used in lanes 3-8. In lanes 1 and 2 ratios of, respectively, 3:1 and 1:1 were used instead. FIG. 10 is a sequence analysis of RT-PCR products derived from NIH3T3 cells transiently transfected with pGF-BHB and pMJ plasmids. Sequences were performed using RT-PCR products eluted from a gel. In the middle, the arrows indicate the intro-flanking nucleotides. FIG. 11 is a scheme of BHB insertions in reporter mRNAs: (A) the different BHB substrates are detailed. The BHB is processed by the MJ endoribonuclease whereas the BHB+3 is not. The BHB-stop structure contains an intron in which three stop codons, blocking all reading frames, are inserted. (B) structures of the GFP-BHB, GFPof and BetaGALof genes, showing the positions of the BHB and the RT-PCR primers used for the experiments shown in (C). (C) splicing analysis of mRNAs derived from NIH3T3 cells transfected with plasmids coding for MJ endonuclease and pGFP-BHB or pGFP-BHB+3 target constructs. The figure shows RT-PCR analysis of different GFP mRNAs in the presence or absence of a functional MJ enzyme. FIG. 12 demonstrates direct GFP fluorescence of transiently transfected NIH3T3 mouse fibroblasts: (A) fluorescence of wt-EGFP, (B) fluorescence of GFPof in presence of the MJ endonuclease, (C) fluorescence of GFPof in presence of the optimized MJ endonuclease, (D) no fluorescence of GFPof is detectable in presence of the inactive endonuclease (MUT-MJ). FIG. 13 is a general scheme for BHB-mediated trans-splicing. FIG. 14 demonstrates that a defective firefly luciferase mRNA is repaired by BHB-mediated trans-splicing: (A) Targeting and target RNAs. Target RNA produces, with Targeting 1 RNA, a bona fide BHB, with Targeting 2 RNA a classical double-stranded RNA. Targeting 1 and Targeting 2 RNAs differ by a total of six nucleotides (in boxes). Both Targeting 1 and Targeting 2 RNAs were transcribed from a CMV immediate early promoter; target RNA was transcribed from a SV40 promoter. (B) RT-PCR analysis shows that both possible recombinant RNAs are generated by the trans-splicing event. (C) Trans-activation of firefly luciferase requires both a bona fide BHB and an optimized MJ endonuclease. FIGS. 15A and B are demonstrations of the presence of the archaeal endonuclease in various tissues of the transgenic mouse. FIG. 15A is a northern blot analysis. FIG. 15B is an immunopurification and western blot analysis. FIG. 16 is a functional analysis of the archaeal tRNA endonuclease obtained from the transgenic mouse (FIG. 16B) and structure and sequence of the substrate utilized in the assay (FIG. 16A). FIG. 17 is a luminescence analysis of hepatic tissue lyates obtained from mice. DETAILED DESCRIPTION OF THE INVENTION In one embodiment, the present invention is a method of RNA cleavage involving substrate recognition by tRNA splicing endonucleases. Example 1 describes features required for eukaryotic endonuclease cleavage. Example 2 describes in vitro experiments designed to cleave a mouse mRNA. Example 3 describes in vivo cleavage and re-ligation of mRNAs in mouse cells. In another example, the present invention is a method for recombining a target RNA molecule that is the bulge-helix-bulge (BHB) conformation with an exogenous, or targeting, RNA molecule. Examples 4 and 5 disclose a splicing reaction in mouse cells. In another embodiment, the present invention is a method of RNA cleavage or RNA cleavage and religation in a mammal. Example 6 demonstrates one embodiment of this aspect of the invention. RNA Cleavage by tRNA Splicing Endonucleases In one embodiment, the present invention is a method of cleaving a double-stranded RNA molecule, wherein the molecule has assumed a bulge-helix-bulge (BHB) conformation. (For a more complete understanding of the structural requirements for the BHB conformation, one should closely examine all figures.) The bulge-helix-bulge conformation comprises an RNA bulge on one strand, a 4 base-pair helix, and an RNA bulge on the opposite strand. The bulges are typically 3 nucleotides in length and the cleavage sites are as described in FIG. 1. In general, the BHB is cleaved (going in the direction 5′-3′) at the bond between the second and third nucleotide at the bulges. In one method of the present invention, one would expose a BHB-containing RNA to a tRNA splicing endonuclease, an enzyme known to be present in all eukaryotic cells and in archeobacteria. The cleavage reaction can be performed both in vitro and in vivo (see Materials and Methods). While the material presented below in the Examples describes certain preferable and typical cleavage reactions, one of skill in the art will know that modifications in reaction conditions, such as enzyme and substrate concentration and buffer and reaction condition components, would be modified to produce successful cleavage reactions. The cleavage is in the absence of the mature domain of the tRNA structure or sequence. The molecule to be cleaved does not require the D, T and acceptor arm of tRNA structure. The BHB could result by the folding of an RNA molecule (BHB in cis) or it could be generated using two different RNA molecules (BHB in trans) (see FIG. 4). One could also design an oligonucleotide capable of forming a BHB structure when hybridized to a target RNA. Therefore, in principle one may target the cleavage site to any desired location on an RNA molecule. Creation of Oligonucleotides One of skill in the art of molecular biology would understand how to create an oligonucleotide that would result the bulge-helix-bulge conformation and appropriate splicing site. Preferably, such an oligonucleotide would be at least between 50 and 70 nucleotides long. Most preferably, the oligonucleotide would be between 58 and 62 nucleotides. In this oligonucleotide, at least approximately 25 (±5 nucleotides) nucleotides would be needed on either side of the bulge-helix-bulge conformation. The oligonucleotide is preferably RNA or a modified RNA molecule. However, we envision that a DNA oligonucleotide would also be suitable. Selection of tRNA Splicing Endonuclease Preferably, one would use in in vitro experiments eukaryal (preferably yeast, Xenopus, C. elegans) and archaeal tRNA splicing endonucleases (preferably M. jannaschii). In in vivo embodiments (preferably mammalian cells) one would preferably utilize endogenous tRNA splicing endonucleases and express one of a battery of archaeal enzymes (Archeoglobus fulgidus, Pyrobaculum aerophilum, Halobacterium sp. NRC-1, Methanocuccus jannaschii). Typically the archaeal enzymes can be expressed in a mouse in a conditional fashion (space and time) utilizing specific mouse promoters. The genes coding for the archaeal enzymes can be cloned from the genome of the original organisms. Preferred Applications One could construct a BHB in trans with any cellular RNA and, therefore, provide cleavage at a desired sequence. Preferred applications include using the RNA cleavage method to cut a target RNA into defined ends with a 2′,3′ cyclic phosphate capable of being ligated. One would also use the present invention to degrade particular targeted RNAs. One could use the present invention to demonstrate the presence of particular RNAs. For example, one could label an oligonucleotide, wherein the oligonucleotide is capable of forming the BHB structure with the RNA target, and look for cleavage products after the duplex has been exposed to the endonuclease. This may be by means of FRET (fluorescence resonance energy transfer), where one would observe a fluorescent signal if the two ends of a fluorescently labeled oligonucleotide probe were separated. Therapeutically, one could use the method of the present invention to treat or remove unwanted RNAs from cells. Particular examples would be viral RNAs. In one embodiment, one would express oligonucleotide probes, wherein the probe is capable of forming the BHB structure with a target RNA, into the desired cell. Endogenous tRNA splicing endonucleases or archaeal enzymes expressed in mammalian cells would then cleave the target RNA. In a preferred form of the present invention, one would avoid the presence of ADAR enzymes (“Adenosine Deaminases Acting on RNA”) by either providing a substitute ADAR substrate (such as excess double-stranded RNA) or designing a target oligonucleotide that is appropriate for cleavage by the tRNA splicing endonuclease but not cleavage by the ADAR. Proteins are traditionally identified on the basis of their individual actions as catalysts, signaling molecules, or building blocks. Our post-genomic view is expanding the protein's roles into an element in a network of protein:protein interactions as well, in which it has a contextual or cellular function within functional modules. The network of protein interaction forms a highly non-homogenous scale-free network in which a few highly connected proteins (hubs) play a central role in mediating interaction among numerous, less connected proteins. The method disclosed in this application allows for the production of fusion proteins, without altering the chromatin structure. In perspective, the fusion of two hubs can be used to generate an algebra of the networks. Laboratory applications of the present invention include, but are not limited to, tagging proteins and conditional production of RNA hairpins. Clinical applications of the present invention include, but are not limited to, mechanisms for correcting mutations and antiviral therapies. Use of Archaeal Enzymes in In Vivo Cleavage and Formation of Fusion RNAs In another form of the present invention, one would cleave in vivo two different RNAs, as described above, and re-ligate the fragments. This embodiment is described in FIGS. 4-6 of the present invention. Typically, one would cotransfect a cell with two plasmids: one coding for an RNA that could form a BHB in trans with another RNA coded by the second plasmid. One could in vivo conditionally (space and time) activate an mRNA containing a BHB inserted in the coding sequence. Excision of the intron and ligation reconstitutes the correct reading frame. In a preferred form of this embodiment, the in vivo cleavage and formation of fusion RNA is within a cell selected from mammalian cells, plant cells and eubacterial cells. Preferably, the cleavage and re-ligation is within mammalian cells. Additionally, the present invention is the creation and use of transgenic mammalian expression systems. Example 6 describes the creation and use of a transgenic mouse. In principle, one could generate a zoo of mice conditionally (in space and time) expressing the archaeal enzyme. These mutant mice could be used to correct specific genetic defects or to generate fusion proteins. The Examples below describe a preferred manner of setting up such an in vivo or in vitro embodiment. Of course, one of skill in the art would understand that modifications in enzyme and substrate concentration and reaction conditions would be within the scope of the invention and not affect the ultimate creation of cleavage products and formation of fusion RNA. EXAMPLES Materials and Methods: Targeted RNA Cleavage by tRNA Splicing Endonuclease (Examples 1 and 2) Amplification PCR was performed in 100 μl reaction containing 5-10 fmole of template, 100 μM of each primer, 125 μM dNTP, 1.5 mM MgCl2, 50 mM KCl, 10 mM Tris-HCl pH 8.2, 5 U of native Taq Polymerase (Perkin-Elmer) under the following conditions: 95° C. 30 seconds, 55° C. 10 seconds, 72° C. 2 minutes for 18 cycles. The DNA phenol extracted and ethanol precipitated. Transcription Transcription of templates by T7 RNA polymerase was performed in 40 mM Tris HCl pH 8.0, 6 mM MgCl2, 10 mM dithiothreitol, 2 mM spermidine, 500 μM ATP, CTP and GTP and 100 μM UTP, 2.5 mM 5′ GMP, 2.5 μM [a32P] UTP (800 Ci/mmole, Amersham) using 5 U/μl T7 RNA polymerase (Pharmacia), 0<1 U/μl RNAguard (Pharmacia) at 37° C. for 90 minutes. After phenol extraction and ethanol precipitation, transcripts were purified on a 8% denaturing acrylamide gel, eluted and ethanol precipitated. Endonuclease Assay Labeled precursors (0.7 nM) were incubated in 30 μl reaction mixture containing 10 mM HEPES pH 7.5, 7 mM MgCl2, 70 mM NH4Cl, 2.5 mM dithiothreitol, 10% glycerol (v/v) with 10 μl of purified endonuclease at 22° C. for 30 minutes. Cleavage products were analyzed by gel electrophoresis on 12% denaturing polyacrylamide gels. tRNA Synthesis Pre-tRNAPhe and pre-tRNAPhe(U-A G-C)∇ were synthesized as described (E. Mattoccia, et al., Cell 55:731-738, 1988; M. I. Baldi, et al., Science 255:1404-1408,1992; E. Di Nicola Negri, et al., Cell 89:859, 1997). Templates for the synthesis of the Archaeuka precursors were constructed by polymerase chain reaction (PCR). The PCR templates were the full-length pre-tRNAs. One primer contained the T7 promoter and part of the 5′ exon. The other was comprised of the desired sequence of the 3′ exon. Conditions for PCR, transcription by T7 RNA polymerase, and endonclease assays were as described (E. Mattoccia, et al., supra, 1988; M. I. Baldi, et al., supra, 1992; E. Di Nicola Negri, et al., supra, 1997). Xenopus laevis endonuclease was purified as in D. Gandini Atardi (D. Gandcini Atardi, et al., Methods Enzymol. 181:510-517, 1989). Transcription We utilized Ambion Megascript kits. Transcription products were purified on 8 M urea polyacrylamide gels. After elution the products were alcohol precipitated. Annealing to Produce dsRNA Annealing was at 60′ at 68° C. in 50 mM TRIS-HCl pH 7 300 mM NaCl 2 mM EDTA, with slow cooling to 35° C., purification on polyacrylamide gels, elution and alcohol precipitation. The concentration of each strand was 0.01 mg/ml. X.I. Endonuclease Assay The assay was for 90′ at 25° C. in 30 ml total volume 10 mM Hepes pH 7.5, 70 mM NH4Cl 7 mM MgCl2m 2.5 nN DTT, 10% glycerol, substrate 2 nM. M.J. Endonuclease Assay The assay was for 30′ at 65° C. in 30 ml total volume 40 mTRIS-HCl pH 7.5 5 mM MgCl2, 10% glycerol, 50 mM, substrate 2 nM. Incubation mixtures were treated with SDS, prot K and phenol, followed by alcohol precipitation. Products were analyzed in 8 M urea polyacrylamide gels. Samples were treated with urea for 5′ at 65° C. or with formamide for 5′ at 95° C. Example 1 Eukaryal tRNA splicing endonucleases use the mature domains of pre-tRNAs as their primary recognition elements. However, they can also cleave in a mode that is independent of the mature domain, when substrates are able to form the bulge-helix-bulge structure (BHB), which is cleaved by archaeal tRNA endonucleases. We present evidence that the eukaryal enzymes cleave their substrates after forming a structure that resembles the BHB. Consequently, these enzymes can cleave substrates that lack the mature domain altogether. That raises the possibility that these enzymes could also cleave non-tRNA substrates that have a BHB. As predicted, they can do so both in vitro and in vivo. Introduction Accuracy in tRNA splicing is essential for the formation of functional tRNAs, and hence for cell viability. In both Archaea and Eukarya the specificity of splicing resides in recognition of tRNA precursors by tRNA splicing endonucleases (Belfort and Weiner, Cell 89:1003-1006, 1997; Trotta and Abelson, The RNA World, pp. 561-583,1999). Archaeal tRNA splicing endonucleases cleave pre-tRNAs only using an RNA structure comprised of two bulges of three nucleotides each (where cleavage occurs) separated by four base pairs. This structure, called the bulge-helix-bulge (BHB) (FIG. 1A, 2) (Daniels, et al., J. Biol. Chem. 260:3132-3134, 1985; Diener and Moore, Mol. Cell. 1:883-894, 1998), functions independently of the part of the molecules that constitutes the mature tRNA, so we refer to this type of recognition of the cleavage sites as being the mature-domain independent mode. In contrast, eukaryal tRNA splicing endonucleases require interaction with the mature tRNA domain for orientation, so we refer to that recognition as the mature-domain dependent mode (Mattoccia, et al., Cell 55:731-738, 1988; Reyes and Abelson, Cell 55:719-730,1988). Recognition of pre-tRNAs by eukaryal tRNA splicing endonucleases normally requires the mature tRNA domain, as well as a base-pair, called the anticodon-intron (A-I) pair (FIG. 1A), which is formed between nucleotides in the anticodon loop and the intron (Baldi, et al., Science 255:1404-1408, 1992). The A-I pair must be at a fixed distance from the mature domain for cleavage to occur and cleavage near this base pair generates the 3′ splice site. An independent cleavage event, also at a fixed distance from the mature domain (usually at a purine), generates the 5′ splice site. The two modes of substrate recognition are characterized by two distances. In the mature-domain independent mode the helix of the BHB sets the distance between the two bulges; in the mature-domain dependent mode the distance is fixed relative to reference in the mature domain. While the subunit structures of the eukaryal and archaeal enzymes differ significantly (Trotta and Abelson, supra, 1999), as do the superficial structures of the cleavage sites, we have demonstrated that both the Xenopus and yeast tRNA splicing endonucleases can operate in the mature-domain independent mode, characteristic of Archaea (Fabbri, et al., Science 280:284-286, 1998). The results reported in this paper explain why the eukaryal endonucleases retain the ability to operate in the mature-domain independent mode when their natural substrates do not have a BHB. Results and Discussion FIG. 1A depicts the A-I interaction. A conserved purine residue in the intron three nucleotides from the 3′ cleavage site (molecule 1, R in box) must pair with a pyrimidine in the anticodon loop 6 nucleotides upstream of the 5′ cleavage site (molecule 1, Y in box) to form the A-1 (for anticodon-intron) interaction (Baldi, et al., supra, 1992). BHB (molecule 2): Two bulges of three nucleotides each (where cleavage occurs) rigidly separated by four base pairs (Daniels, et al., supra, 1985; Diener and Moore, supra, 1998). BHL (molecule 3): A three-nucleotide 3′ site bulge, a four base-pair helix and a loop containing the 5′ site. Pre-tRNAArcheuka and its variants (molecule 4): The hybrid pre-tRNA molecule pre-tRNAArcheuka is a substrate for both the eukaryal and archaeal endonucleases. It consists of two regions derived from yeast pre-tRNAPhe (nucleotides (nt) 1-31 and not 38-76) joined by a 25 nt insert that corresponds to the BHB motif of the archaeal pre-tRNATrp. It has a typical eukaryal mature domain with cleavage sites located at the prescribed distance from the reference elements and a correctly-positioned A-I base pair, all of which should ensure correct recognition by the eukaryal endonuclease when the enzyme operates in the mature-domain dependent mode. In addition, the presence of the BHB motif confers substrate characteristics that are recognizable by the eukaryal enzyme when it operates n the mature-domain independent mode. FIG. 1B depicts a substrate cleaved in both the mature-domain dependent and the mature domain independent modes. Products of digestion by the Xenopus tRNA splicing endonuclease. Molecule 1: Pre-tRNAArcheuka 3bpΔas; molecule 2: Pre-tRNAArcheuka 3bpΔas, C56G. FIG. 2A shows that the Xenopus endonuclease can cleave in vivo in the mature-domain independent mode. Low amounts of 32P-labeled RNAs corresponding to Pre-tRNAPhe (1); Pre-tRNAArcheuka (2) and Pre-tRNAArcheuka 2bp∇as (3) were injected into nuclei of Xenopus oocytes and 2 hours later the intracellular distribution of the injected primary pre-tRNA transcripts and of the mature tRNAs were determined by analysis of total nuclear (N) and cytoplasmic (C)RNAs. The injected precursor RNAs in the cytoplasm probably resulted from inefficient nuclear retention, I., input. FIG. 2B shows that the yeast endonuclease mutant sen2-3 cleaves pre-tRNAArcheuka at both sites. Molecule 1, pre-tRNAPhe; molecule 2, pre-tRNAArcheuka; molecule 3, Pre-tRNAArcheuka 3bp∇BHB, C8G, G24C, X. Xenopus laevis; Y, yeast S. cerevisiae wild-type; Y* yeast S. cerevisiae sen2-3. The sen2-3 preparation was contaminated with a 3′ exonucleolytic activity that partially degraded the 3′ end of the precursor, reducing the size of the 3′ half product. The sequences of the products of the intron excision reaction have been verified by fingerprinting (data not shown). In the sen2-3 mutant, one residue in loop L7, Gly292, is changed to Glu (Trotta and Abelson, supra, 1999). Loop 7 contains a histidine residue that is absolutely conserved in all tRNA endonucleases, and that probably acts as a general base by deprotonating the nucleophile 2′-hydroxyl group (Trotta and Abelson, supra, 1999). The residues on loop 7 immediately surrounding the conserved histidine residue are not conserved among the tRNA endonucleases. We suggest that these residues have a role in the restructuring of the 5′ cleavage site in the eukaryal enzymes. FIG. 2C is a comparison of models of enzyme-substrate interaction: (a) Pre-tRNAArcheuka Eukaryal enzyme (Trotta and Abelson, supra, 1999), (b) Pre-tRNAArcheuka Archaeal enzyme (Trotta and Abelson, supra, 1999), and (c) BHB Eukaryal enzyme. A proposal for loss of symmetry during evolution of the intron excision reaction. In Archaea, the recognition element in pre-tRNA is the BHB, which has pseudo-two-fold symmetry (Diener and Moore, supra, 1998; Trotta and Abelson, supra, 1999). Since the endonuclease does not bind to the mature domain of pre-tRNA, the enzyme is oriented in such a ways that both active sites can cleave either of the intron-exon junctions (b). The primary recognition element of the eukaryal endonuclease, on the other hand, is the asymmetrically located mature domain of pre-tRNA; interaction with that domain imposes an orientation of the enzyme on the substrate, so that each active site is specific to one or the other intron-exon junctions. In the absence of a mature domain, as with the mini-BHB (Febbri, et al., supra, 1998), the eukaryal enzyme is free to recognize pseudo-two-fold symmetric elements in the substrate, so that both active sites in the enzyme can bind to either junction (c). However, when a substrate has both a mature domain and a symmetric BHB, as in pre-tRNAArcheuka, the eukaryal endonuclease can interact with the mature domain, and the added energy of this binding would be likely to orient the enzyme (a). We propose that during evolution, once endonucleases were able to recognize the mature domain, the need for a symmetric BHB recognition site diminished; however, the active sites of the eukaryal enzymes were maintained, allowing them to cleave pre-formed BHB structures. Because the orientation of the two cleavage sites in the enzyme remained constant, the eukaryal pre-tRNAs had to maintain the ability to form a BHB-like structure upon binding the eukaryal enzyme; part of that requirement is seen in the -A-I base pairing rule and in the BHL. The artificial substrate pre-tRNAArcheuka contains both a mature domain and a BHB (FIGS. 1A, 2). The eukaryal enzymes cleave the substrate with a two base-pair insert in the anticodon stem, 2bp∇as (FIGS. 1A, 4), only in the mature-domain independent mode (Fabbri, et al., supra, 1998). The sites of cleavage by the eukaryal enzyme are fixed by recognition of local BHB structure rather than by reference to the mature domain. The Xenopus laevis endonuclease can also cleave in vivo in the mature-domain independent mode. When pre-tRNAArcheuka and pre-tRNAArcheuka 2bp∇as were injected into Xenopus oocyte nuclei, both substrates were spliced and ligated. The size of the mature pre-tRNAArcheuka 2bp∇as, which is four bases longer than mature wild-type pre-tRNAPhe, indicates that the Xenopus enzyme cleaves in the mature-domain independent mode in vivo just as it does in vitro (FIG. 2A). The substantial amounts of each precursor exported before cleavage probably results from saturation of nuclear retention (Arts, et al., EMBO J. 17:7430-7441, 1998; Lund and Dahlberg, Science 282:2082-2085, 1998). Some substrates are cleaved in both modes. Pre-tRNAArcheuka 3bpΔas (FIG. 1B), which has a three base-pair deletion in the anticodon stem, is cleaved in both modes. In this case, the two modes yield distinct product sizes, and both are observed. Two introns are visible in FIG. 1B, lane 1. One of the products is not produced in the C56G mutant reflecting the inability of the enzyme to cleave a substrate that cannot form a normal mature domain in the mature-domain dependent mode. We now propose that the orientation of the substrate in the active site of the eukaryal enzyme requires the formation of a structure that resembles a BHB; the A-I pair would play a pivotal role in this process, as it represents the closing base pair of one of the bulges. This model predicts that recognition of the mature tRNA domain by a eukaryal tRNA splicing endonuclease allows subsequent formation of a BHB-like cleavage structure. In addition to the A-I pair (Baldi, et al., supra, 1992), other relics of the archaeal world provide insight into the mechanism of the eukaryal cleavage reaction. Some eukaryal pre-tRNAs present motifs that resemble the BHB. The sequence of the Caenorhabditis elegans genome shows the tRNA genes corresponding to three isoacceptor species (Leu, Tyr, Ile) contain introns (The C. elegans Sequencing Consortium, 1998). The nematode pre-tRNAs present a motif which we call BHL (FIGS. 1A, 3), which resembles the BHB in that it has the 3′ site bulge and the four base-pair helix but the 5′ site is in a loop rather than in bulge. These three intron-containing pre-tRNAs of C. elegans are cleaved correctly by both yeast and Xenopus endonucleases, as well as the Parascaris equorum tRNA splicing endonuclease, but not by the archaeal enzyme (data not shown). Thus, the only truly universal substrate is an RNA with a BHB (Fabbri, et al., supra, 1998). Because they can both cleave the BHB, the archaeal and eukaryal endonucleases are likely to have identical dispositions of active sites, a feature conserved since their divergence from a common ancestor (Trotta and Abelson, supra, 1999; Fabbri, et al., supra, 1998) (FIG. 2C). We suggest that the mature-domain dependent mode arose through specialization of the subunits of the eukaryal enzyme. We propose that the eukaryal enzymes possess a mature-domain dependent 5′ site restructuring activity (Di Nicola, et al., Cell 89:859-866, 1997). Such an activity would be required for the last steps of substrate recognition by the eukaryal enzymes, recapitulating the recognition process of their archaeal counterparts. The 5′ site restructuring activity is not needed to cleave the BHB because it already has a correctly structured 5′ site; however the activity is responsible for improving the efficiency of cleavage at the 5′ site in BHL (P. Fruscoloni, M. Zamboni, M. I. Baldi and G. P. Tocchini-Valentini, manuscript in preparation). The Ascaris enzyme also has a mature-domain dependent 5′ restructuring activity, but it differs from that of Xenopus because it is unable to restructure a typical eukaryal pre-tRNA such as yeast pre-tRNAPhe (P. Fruscoloni, M. Zamboni, M. I. Baldi and G. P. Tocchini-Valentini manuscript in preparation). Our model predicts the existence of mutants of the eukaryal enzyme that lack the 5′ restructuring activity. Such mutants would be unable to cleave a eukaryal pre-tRNA at the 5′ site, but could cleave at the 3′ site. More importantly, these restructuring mutants should cleave precursors that already have a BHB. The yeast endonuclease is an αβγó heterotetramer (Trotta, et al., Cell 89:849-858, 1997). Homology relationships and other evidence suggest that two subunits of the enzyme, Sen2p and Sen34p, contain distinct active sites, one for the 5′ site, the other for the 3′ site. The mutant sen2-3 is defective in cleavage of the 5′ site (Ho, et al., EMBO J. 9:1245-1252, 1990); FIG. 2B shows that sen2-3 extracts cleaves the 3′ but not the 5′ site of yeast pre-tRNAPhe. The same extract, however, cleave pre-tRNAArcheuka at both sites (FIG. 2B). Thus, sen2-3 cleaves the 3′ but not the 5′ sites in substrates lacking a BHB, as would be expected if it lacked the mature-domain dependent 5′ site restructuring activity. This conclusion is reinforced by the fact that pre-tRNAArcheuka 3bp∇BHB, a substrate that can interact with the enzyme only in the mature-domain dependent mode, is cleaved only at the 3′ site (FIG. 2B). It is unlikely that the lack of cleavage at the 5′ site of pre-tRNAPhe results simply from inactivation of the catalytic site since the mutated amino acid is not near this site, based on the crystal structure of the enzyme (Li, et al., Science 280:279-284, 1998). Moreover, pre-tRNAArcheuka, which has a BHB, is cleaved at both sites even though its mature domain should prevent binding of the sen34 active site to the 5′ site (FIG. 2B). Unfortunately, expression of a sen2-3 and sen34 double mutant enzyme is very likely to be lethal, making production of a doubly mutated enzyme impossible. Example 2 The ability of the eukaryal enzyme to recognize and cleave independently of the mature domain creates the possibility for cleavage of non-tRNA substrates (FIG. 3). If the eukaryal endonuclease can recognize and cleave substrates in the mature-domain independent mode, any RNA that contains a BHB structure should be able to serve as a substrate. Such a target could be generated in mRNA by adding a suitable RNA oligonucleotide. FIG. 3 depicts cleavage of a non-tRNA molecule by the Xenopus endonuclease. Profilin I mRNA duplexes (cartoon) consisting of 32P-labeled sense strand and cold antisense strand (0.6 nM) were incubated with Methanococcus jannaschii endonuclease (MJ for 30 minutes at 65° C.); Xenopus laevis endonuclease (XL for 90 minutes at 25° C.); germinal vesicles extract (GV for 90 minutes at 25° C.). The reacted RNA was treated as described (Mattoccia, et al., supra, 1988; Baldi, et al., supra, 1992; Fabbri, et al., supra, 1998) and analyzed in 8M urea polyacrylamide gels. Two fragments were generated from profilin I mRNA (417 nts and 53 nts). The gel shows only the larger fragment. Unrelated 32P-labeled dsRNA (low specific activity) was added where indicated (the concentration was 300× that of the profilin I duplex). C, duplex containing the BHB; C1, full duplex. FIG. 3 shows that the archaeal and eukaryal enzymes cleave mouse profilin 1 mRNA (Widada, et al., Nucleic Acids Res. 17:2855, 1989), when the RNA is complexed with another oligoribonucleotide forming a BHB. This cleavage occurs in a BHB-dependent manner because fully double-stranded molecules (FIG. 3) and molecules presenting an insertion of three base pairs in the helix of the BHB are not cleaved (data not shown). FIG. 3 shows that cleavage also occurs in extracts of germinal vesicles (GV extracts). Again, cleavage is BHB-dependent. However, cleavage in this extract occurred only in the presence of a 100-fold excess of unrelated double-stranded RNA (dsRNA). Pre-tRNAArcheuka, on the contrary, is cleaved at high efficiency (data not shown). An explanation for these differences is the presence in GV extracts of adenosine deaminases (ADARs) that convert adenosines to inosines within dsRNA (Bass and Weintraub, Cell 35:1089-1098, 1988), thereby causing the RNA duplex to fall apart, disrupting the BHB structure. Presumably, at low concentration of dsRNA, ADARs deaminate the substrate and, as a result of the increased single-stranded character of the molecule, the BHB is destroyed. Our results indicate that the formation of a BHB is an obligate step in cleavage by the eukaryal endonucleases and explain why the eukaryal endonucleases retain the ability to operate in the mature-domain independent mode when their natural substrates do not have a BHB. Example 3 This work is disclosed in Deidda, et al., Nat. Biotechnol. 12:1499-1504, 2003, incorporated by reference. RNA Engineering Various approaches are currently being used to elucidate the principles that underlie the construction and function of eukaryotic cells and organisms. Some of these approaches, such as gene targeting or the gene trap technology, operate at the level of the DNA. Others, like the Tet system, regulate gene expression at the level of transcription. Yet another kind of approach, such as induced dimerization, works at the protein level. It is becoming clear that processes occurring at the RNA level such as, for example, alternative splicing and editing, play an extremely important role in expanding protein diversity and might therefore be partially responsible for the apparent discrepancy between gene number and complexity. Developing a full catalogue of transcripts corresponding to a single gene and determining each of their functions will be a major challenge of the proteomic era. What is needed is a technology that makes RNA engineering possible. The BHB is recognized and cleaved by archaeal and eukaryal tRNA endonucleases. It is therefore possible to generate non-tRNA substrates for the enzymes; any RNA that contains a BHB structure is capable of serving as a substrate. Such a target can be generated in mRNA either by inserting a BHB in cis in the coding or untranslated regions, or by adding a suitable RNA oligonucleotide to form a BHB in trans. In mouse cells, we have found that the halves generated by cleavage of BHB in cis in a mRNA molecule are ligated by an endogenous ligase activity. FIG. 4 shows that, when the BHB is formed in trans by two different RNA molecules, a fusion mRNA may result. A sequence was inserted in the coding region of the GFP gene so that the transcription of the coding strand yields an mRNA harbouring a canonical BHB (FIG. 5). The mutated GFP gene was named “GFPof,” since the presence of the intron in the messenger renders the latter out of frame. Production of GFP requires that the intron be precisely excised and that the exons be subsequently ligated. FIG. 6 shows that if 3T3 cells are transiently cotransfected with a plasmid expressing GFPof and a plasmid expressing the M. jannaschii endonuclease, GFP is produced. If a plasmid expressing an inactive endonuclease is utilized, GFP is not produced. These results suggest that the M. jannaschii endonuclease excises the intron and that an endogenous ligase activity produces a spliced mRNA that is correctly translated. This conclusion is substantiated by the finding that a new RNA species appears (FIG. 7) and that its sequence (FIG. 8) corresponds to that expected for spliced GFP mRNA. In addition, FIG. 7 shows that GFPof+3 mRNA, a transcript characterized by an insertion of three base pairs in the helix of the BHB (FIG. 5), is not spliced. TRNA endonucleases do not tolerate the expansion of the helix of the BHB. GFPof stop mRNA (FIG. 5), a transcript characterized by a twenty-three base long intron containing three stop codons in the three reading frames, is accurately spliced (FIG. 7). A spliced species is also produced when the BHB is not positioned in the coding region. In GFP-BHB mRNA (FIG. 5), the BHB is located in the 3′ untranslated region. FIG. 9 shows that if 3T3 cells are transiently cotransfected with a plasmid expressing GFP-BHB and a plasmid expressing the M. jannaschii endonuclease, a new RNA species appears whose sequence (FIG. 10) corresponds to that of accurately spliced GFP mRNA. Structure-Specific Non-Spliceosomal Splicing of mRNA The Methanococcus jannaschii tRNA endonuclease recognizes and cleaves its normal substrates at bulge-helix-bulge (BHB) motifs that define the intron-exon boundaries in archaeal tRNAs and rRNAs. We show that this enzyme also cleaves on either end of a small intron inserted into a eukaryal mRNA encoding the green fluorescent protein (GFP). Moreover, the cleavage products are subsequently ligated together by endogenous RNA ligases in a reaction resembling that described for the HAC1 mRNA. Introns included in the BHB, located in either the coding region or the 3′ UTR, were excised from GFP mRNAs when the gene encoding the M. janaschii enzyme was transfected into NIH3T3 cells. Our assays for proper ligation included detection of GFP by fluorescence microscopy and RT-PCR. Disruption of the BHB by extension of the helix results in no splicing. These experiments demonstrate that the archaeal enzyme can recognize the BHB motif even in the context of a mammalian mRNA. This enzymatic system offers an opportunity to modulate gene expression in vivo. Materials and Methods Gene Expression Constructs Plasmids Coding for mRNAs Containing the BHB Structure. Splicing-Dependent Translation GFP-OF was obtained by amplifying the GFP gene from the pEGFP-N3 expression vector (Clontech). The GFP was sequentially amplified with two set of primers: P1 VS P3 and P2 VS P3. A new start codon embedded in a Kozak sequence was inserted and the natural GFP start codon was mutated with the introduction an AgeI site. Moreover, a FLAG epitope coding sequence separated from GFP was separated by the BHB structure. The FLAG and the GFP are coded on two different frames but they switch to the same frame when the BHB is correctly spliced. The modified GFP (GFP-OF) was re-inserted into the BglII-NotI sites of the pEGFP-N3 vector (pGFP-OF). Plasmids pGFP-OF+3 and pGFP-Stop were obtained by substitution of the EcoRI-AgeI fragment of pGFP-OF with the double stranded oligonucleotides P4 and P5, respectively. Splicing-Independent Translation Two different constructs containing the BHB in the 3′ UTR were prepared, pGFP-BHB and pGFP-BHB+3. The GFP gene from the pd2EGFP-N1 vector (Clontech) was amplified with the primer pair P2 Vs P8 to add a 35-nucleotide long spacer downstream of the stop codon. The P2-P8 PCR product was then submitted to a new round of PCR with the P2-P6 and P2-P7 primer pairs in order to add the structures BHB and BHB+3, at the 3′ end of GFP-BHB and GFP-BHB+3 products. These PCR products were digested with BglII and NotI and cloned back in the original vector. Plasmids Coding for Methanococcucs Jannaschii tRNA Endonuclease. Construction pMJ plasmid. The M. jannaschii gene with the FLAG epitope at its 5′ end was cloned by PCR from the pET11a bacterial expression vector (Hong Li, et al., Science 280:284, 1998) a kind gift of Dr. Christopher Trotta. The MJ-endoribonuclease PCR product was obtained using the primer pair P14 Vs P15 and cloned BglII-NotI in the pd2EGFP-N1 vector after excision of GFP. The plasmid pMut-MJ was obtained via PCR from pMJ using mutagenic primers. Three aminoacidic substitutions were introduced: His 125 to PHE, LYS 156 to PRO and LYS157 to GLN. The M. jannaschii gene was amplified using three different primer pairs: P14 Vs P17, P16 Vs P19 and P18 Vs P5. All PCR products were mixed and re-amplified with P14 Vs P15. The mutagenized product was digested and cloned as was done for pMJ. TABLE 1 Oligodeoxyribonucleotides P1-GAGCTCAAGCTTCGAATTCCCGGTCGTGACTCCAGAGGCTTACACCGGAGATATCACGACCGGTTGTGAGCAAGGGCGAG P2-ATCACGAGATCTCCACCATGGACTACAAAGACGATGACGATAAACTCGAGCTCAAGCTTCGAATT P3-TCGGGATCCTCTACAAATGTGGTATGGCTG P4-GCTTCGAATTCCCGGTCGTGACTTCTCCAGAGGCTTACACCGGAGAAGATATCACGACCGGTTGTGA P5-GCTTCGAATTCCCGGTCGTGACTCCAGAGGTAACTGACTAAACCGGAGATATCACGACCGGTTGTGA P6-ATAAGAATGCGGCCGCCCGGTCGTGATATCTCCGGTGTAAGCCTCTGGAGTCACGACCGGGGACGGG P7-ATAAGAATGCGGCCGCCCGGTCGTGATATCTTCTCCGGTGTAAGCCTCTGGAGAAGTCACGACCGGGGACGGG P8-TCACGACCGGGGACGGGGGCCCAGACGGAGGGCGAGTCCTTGTAGCGCATCTACACATTGATCCTAGCAGA P9-CGTCAGATCCGCTAGCGCTAC P10-CGTCGCCGTCCAGCTCGACCA P11-TAGATGCGCTACAAGGACTCG P12-TCGGGATCCTCTACAAATGTGGTATGGCTG P14-ATCACGAGATCTCCACCATGGACTACAAAGACGATGACGATAAAATGGTGAGAGATAAAATG P15-ATAAGAATGCGGCCGCGGATCCTTATGGTTTTACATAGG P16-ATAAAGAATTCTCTGTTTATTTGGTTAAGG P17-AACAGAGAATTCTTTATCATGTTAGCTCC P18-TCAGTTCGGCCGCAATTACTCATAGCAATC P19-GTAATTGCGGCCGAACTGAGTGAGCAACC P20-GGCACCACCCCGGTGAACAG P21-GTATGGCTGATTATGATCTAG Culture Conditions and Cell Transfections NIH3T3 fibroblasts were grown in Dulbecco's modified medium (DMEM) supplemented with 10% calf serum in a 37° C. incubator with 5% CO2. Cell transfections were carried out using the Lipofectamine 2000 or Lipofectamine Plus (Gibco-BRL) transfection reagent according to the manufacturer's instructions. Each transfection was performed in a 35 mm dish using 4 μg of total plasmid DNA with Lipofectamine 2000 or 2 μg with Lipofectamine Plus. RNA Preparation and RT-PCR Analysis Total RNA was isolated from cells 24 hours after transfection using the Trizol reagent (Life Technologies) following the manufacturer's instructions. 10 μg of total RNA were treated with 1 unit RQ1 DNAse RNAse free (Promega M610A) for 30′ at 37° C. and phenol/chloroform extracted. Single-strand cDNA was obtained by polyT primed reverse transcription of 3 μg total RNA with SuperScript II RT (Life Technologies 18064-022). pGFPOF, pGFPOF+3 and pGFPOF-STOP mRNAs splicing analysis was performed by PCR using the primer pair P9 Vs P10, whereas the primer pair P11 Vs P12 was used for pGFP-BHB and pGFP-BHB+3 analysis. P9 or P12 primers were P32 labeled. PCR products were electrophoresed on a 6% polyacrylamide, 8M urea 20% formamide gel. The gels were dried and exposed to Phosphorimager for 16 hours and visualized by STORM 860 Phosphorimager (Molecular Dynamics). Sequencing of RT-PCR Products Spliced and unspliced amplified cDNAs were eluted from non-dried polyacrylamide denaturing gels and submitted to a new round of PCR. The P9-P10 primer pair was used for products derived from pGFPOF, pGFPOF+3 and pGFPOF-STOP mRNAs. P11-P12 was used for products derived from pGFP-BHB and pGFP-BHB+3. Sequence reactions were performed using a Bigdye sequencing kit (Perkin Elemer-Applied Biosystem) primed with P20 for products derived from the first plasmid group and with P21 for those derived from the second plasmid group. Sequences were analyzed on a ABI Prism 310 gentic analyser (Applied Biosystem). Immunoblotting Analysis Cell lysates were obtained with RIPA buffer (20 mM hepes PH 7.5, 1% Triton X-100, 150 mM NaCl, 10 mM EDTA), added with complete reagent (protease inhibitor cocktail tablets, Roche cat. 1697-498) and then subjected to SDS-PAGE (15%). Proteins were transferred to a PVDF membrane (immobilon P, Millipore). Membranes were blocked with 5% low-fat milk in TBST and incubated first with mouse anti-FLAG M2 monoclonal antibody (SIGMA F-3165) in Tris Buffered Saline (10 mM tris-Cl at pH 7.5, 150 mM NaCl) containing 0.05% Tween20 and then with HRP-conjugated goat anti-mouse IgG-1(γ) (Caltag M32007). Immunoreactive bands were detected by ECL (Supersignal West Pico Chemiluminescent Substrate, Pierce). Immunofluorescence Detection of Methanococcus jannaschii tRNA endonuclease. Twenty-four hours after plasmid transfection, cells were fixed with 2% paraformaldehyde/0.1% Triton X100 for 20 minutes, washed three times with PBS/1% BSA and incubated with mouse anti-FLAG M2 monoclonal antibody (SIGMA F-3165) in PBS 1% BSA. Cells were then washed and incubated with FITC-conjugated goat anti-mouse IgG-1 (y) (Caltag cat. M32101). Visualization of GFP protein in transfected cells. Forty-eight hours after transfection, cells were fixed with 2% paraformaldehyde/0.1% Triton X100 for 20 minutes, incubated for 10 minutes with 1 μg/ml Hoechst/PBS 1× solution and washed twice with PBS. All coverslips were mounted with 80% Glycerol/PBS mounting media. The images were taken by fluorescence microscopy (Olympus AX 70) with a Nikon digital camera (Coolpix 990) and processed with Adobe Photoshop version 5.0. Examples 4-6 This invention also relates to a method for recombining a target RNA molecule that is in the bulge-helix-bulge (BHB) conformation with an exogenous, or targeting, RNA molecule. As described above, the target RNA molecule has been shown to be cleaved within the bulge-helix-bulge. When the cleaved target RNA molecule and the exogenous RNA molecule are exposed to an appropriate ligase, RNA chimeras form, recombining the target RNA molecule and the exogenous RNA molecule across the bulge-helix-bulge. The method of the present invention can be used for recombining RNA molecules can be used for altering RNA function, in that the recombination may be used to destroy RNA function, modify RNA, or even restore RNA function. Laboratory applications of the present invention include, but are not limited to, tagging proteins and conditional production of RNA hairpins. Clinical applications of the present invention include, but are not limited to, mechanisms for correcting mutations and antiviral therapies. By expressing an archaeal tRNA endonuclease (the Methanococcus Jannaschii endonuclease) in mouse cells, RNAs can be cleaved if they form the BHB (bulge-helix-bulge) structures that are recognized by the enzyme (J. Abelson, et al., J. Biol. Chem. 273:12685-8, 1998). The resulting cleavage products are joined together by an endogenous ligase. The utility of this strategy was illustrated with reporter targets EGFP and β-galactosidase mRNAs into which 17-nucleotide introns, flanked by sequences capable of forming BHB structures in cis, were introduced. RNA molecules that can form BHB substrates in trans with targeted mRNAs were also designed. Cotransfection of mouse cells with plasmids expressing these RNAs and the MJ endonuclease led to formation of RNA chimeras in which the target and exogenous RNA were recombined across the BHB. A nonfunctional firefly luciferase mRNA was repaired efficiently by this trans-splicing. This technology is not limited to mRNA, but could in principle be used to destroy, modify or restore the function of a vast repertoire of RNA species or to join selectable tags to target RNAs. Example 4 In mouse cells, as in other eukaryotic cells, messenger RNA introns are removed by a large ribonucleoprotein assemblage called the spliceosome, using a catalytic mechanism similar to that employed for group 11 introns. Spliceosomes recognize 5′ and 3′ splice sites, which are located at exon-intron boundaries. The splicing reaction occurs in two steps. First, the 5′ end of the intron is joined to an adenine residue in the branchpoint sequence upstream from the 3′ splice site to form a branched intermediate called an intron lariat. In the second step, the exons are ligated and the intron lariat is released (M. J. Moore, et al., The RNA World (Cold Spring Harbor Laboratory Press, New York, 1993). Cis-splicing, converting pre-mRNA to mRNA, is essential for gene expression. An uncommon and less characterized mechanism for RNA processing involves trans-splicing between different pre-mRNA molecules; this process, again catalyzed by the spliceosome, has been demonstrated to form hybrid mRNAs in a number of eukaryotic systems (T. Maniatis and B. Tasic, Nature 418:236-243, 2002). The spliceosome places a group of five proteins a few nucleotides proximal to the site where an intron has been cut out and two fragments have been joined. Some of these proteins are stripped away as the RNA exits through the nuclear pore and the remaining proteins can determine the fate of the mRNA. For example, those proteins can trigger NMD (nonsense mediated decay), a proofreading process that results in the specific destabilization of mRNA molecules that contain premature translation termination codons (J. E. Dahlberg, et al., RNA 9:1-8, 2003). Not all mRNA splicing uses a spliceosomal system. A striking example has been described in yeast. HAC1 mRNA, coding for a transcription factor, is spliced by a unique mechanism that does not require the spliceosome (T. N. Gonzalez, et al., EMBO J. 18:3119-3132, 1999). The splice junctions of HAC1 pre-mRNA do not conform to the consensus sequences of other yeast pre-mRNAs. The spliceosome is bypassed by a site-specific endoribonuclease that cleaves the precursor specifically at both splice junctions and by the RNA ligase that completes the splicing (C. Sidrauski, et al., Cell 87:405413, 1996). We have engineered a new non-spliceosomal splicing system in mouse cells, utilizing components normally involved in the splicing of archaeal pre-tRNAs. Archaea do not appear to carry the group I introns, group II introns, or nuclear mRNA-type introns that are found in eukaryotes and/or bacteria (J. Abelson, et al., supra, 1998). Instead, they have introns in their tRNA and rRNA genes that are spliced by an apparently archaeal-specific mechanism. All archaeal intron transcripts generate a ‘bulge-helix-bulge’ motif at the exon-intron junction. The BHB motif consists of two 3-nucleotide bulges on opposite strands of an RNA, separated by a helix of 4 bp (FIG. 11A). An enzyme, the splicing endonuclease, cleaves at symmetrical positions within each of the 3-nt bulges present on the same minor groove face of the central 4-bp helix of the BHB motif, resulting in 2′,3′-cyclic phosphate and 5′-OH ends. (J. Abelson, et al., supra, 1998; L. D. Thompson and C. J. Daniels, J. Biol. Chem. 265:18104-18111, 1990; J. Lykke-Andersen and R. A. Garrett, J. Mol. Biol. 243:846-855,1994; J. L. Diener and P. B. Moore, Mol. Cell. 1:883-894, 1998) Mutational analyses, secondary structure probing, and sequence analyses have shown that the conformation of the BHB motif is much more important for archaeal endonuclease/RNA recognition than its sequence (J. L. Diener and P. B. Moore, supra, 1998). The addition of one base pair to the central helix results in the loss of accurate endonucleolytic cleavage. The structure of the BHB motif has been determined by NMR spectroscopy. The conformations of the two 3-nt bulges are stabilized by stacking interactions between bulge nucleotides and bases in the adjacent Watson-Crick helices and also by a network of backbone hydrogen bonds. Both bulges are presented on the same minor groove face of the central 4-bp helix, and the overall structure has approximate two-fold symmetry (J. L. Diener and P. B. Moore, supra, 1998), which makes it well-suited for attack by archaeal splicing endonucleases, which are essentially symmetric dimers that can cleave non-tRNA substrates, for example pre-mRNAs, provided they have a BHB. We chose to express the archeon Methanococcus jannaschii tRNA endonuclease in mouse cells. The M. jannaschii enzyme is a homotetramer; the monomer is small, consisting of only 179 amino acids. The crystal structure is known and His-125, Tyr-115 and Lys-156 represent the catalytic triad responsible for the cleavage reactions (H. Li, et al., Science 280:279-284,1998). An endogenous mouse ligase ligates the fragments produced by the archaeal endonuclease. We demonstrate both cis and trans non-spliceosomal splicing in mouse cells, catalyzed by the MJ endonuclease. A single pre-mRNA molecule can be subjected to both spliceosomal and non-spliceosomal splicing. We produced four constructs containing sequences coding for the endonuclease: pMJ, pMUT-MJ, pOPTI-MJ and pOPTI-MUT-MJ. The first, pMJ was obtained by cloning the archaeal endonuclease gene in a mammalian expression vector under the control of the CMV (cytomegalovirus) immediate early promoter. A sequence coding for the FLAG epitope was inserted in order to obtain expression of the epitope at the N terminal of the protein. The second, pMUT-MJ, was derived directly from pMJ by introducing, via PCR, three amino acid changes at positions 125 (H to F), 156 (K to P) and 157 (K to Q). The substitutions, two of which concern the catalytic triad (J. Abelson, et al., supra, 1998), produce an inactive enzyme. The third construct, pOPTI-MJ, permits high expression of the enzyme and codes for a protein identical to that expressed by pMJ. The coding sequence was changed, taking into account the murine codon usage. The fourth construct, pOPTI-MUT-MJ, was derived from pOPTI-MJ by introducing the three amino acid changes described above. We used anti-FLAG antibodies to perform immunofluorescence analysis of NIH3T3 cells, transfected with pMJ, pMUT-MJ, pOPTI-MJ and pOPTI-MUT-MJ. Western blotting showed that all four constructs code for a protein of the correct size (data not shown). Three different sets of constructs, coding for target RNAs, were produced. The first set includes pGFP-BHB and pGFP-BHB+3. These plasmids code for target RNAs presenting the BHB in the 3′ untranslated region (FIG. 11B). pGFP-BHB+3 codes for transcripts characterized by a BHB that presents an expanded helix resulting from the insertion of three base pairs. The altered BHB cannot be cleaved by the endonuclease (J. Abelson, et al., supra, 1998). The second set includes pGFPof (out of frame), pGFPof+3 and pGFPof-stop. All three code for N-terminal FLAG-EGFP, characterized by the absence of the original ATG at the beginning of the EGFP and by the presence of a new ATG and a Kozak sequence (M. Kozak, Nucleic Acids Res. 15:8125-8148, 1987) preceding the sequence coding for the FLAG. In pGFPof, a sequence capable of forming a BHB in the transcript has been inserted between the sequence coding for the FLAG and that coding for the EGFP. As a result of the insertion, the EGFP sequence is out of frame relative to the FLAG sequence. Precise excision of the 17-base intron and subsequent ligation of the halves reconstitutes the correct reading frame. pGFPof+3 codes for transcripts characterized by a BHB, that, like the one encoded by pGFP-BHB+3, presents an expanded helix resulting from the insertion of three base pairs. The altered BHB cannot be cleaved by the endonuclease. The transcript coded by pGFPof-stop is characterized by an intron containing three stop codons (FIG. 11A), that should block any translation initiating at non-AUG codons eventually induced by the presence of a secondary structure, in this case that of the BHB, just downstream from the alternative initiator codon (M. Kozak, Proc. Natl. Acad. Sci. USA 87:8301-8305,1990). In order to validate results obtained with the GFP constructs by an independent assay, we created a third type of plasmid coding for target RNA, pBetaGALof. This plasmid codes for a β-galactosidase gene that is out of frame relative to its ATG because it contains a BHB structure as previously described for pGFPof. A spliceosomal intron is also present in the 5′ untranslated region of pBeta-GALof mRNA (FIG. 11B). Our strategy is based on the expectation that the MJ enzyme would cleave the BHB twice and remove the intron sequence, leaving behind two half-molecules. The 5′ half-molecule bears a 2′-3′-cyclic phosphate terminus, and the 3′ half-molecule bears a 5′ hydroxyl terminus (J. Abelson, et al., supra, 1998). Two RNA ligase activities, that could ligate these two half-molecules, have been biochemically identified in mammalian cells. The two RNA ligase activities are mechanistically different. The first activity uses the phosphate from the 2′3′-cyclic phosphodiester to form the 3′-5′ phosphodiester linkage at the ligation junction (W. Filipowicz, et al., Nucleic Acids Res. 11:1405-1418,1983; K. K. Perkins, et al., Proc. Natl. Acad. Sci. USA 82:684-688,1985). Although it has been shown to ligate polyribonucleotides in vitro, very little is known about this activity in vivo and, for instance, whether it is able to join non-tRNA substrates. The second mammalian RNA ligase activity incorporates an exogenous phosphate (obtained from a nucleoside triphosphate) at the junction and creates a 2′ phosphomonoester, 3′-5′ phosphodiester linkage intermediate. A separate 2′ phosphatase activity later removes the 2′ phosphate moiety. The second mammalian ligase activity is functionally analogous to the only RNA ligase described in yeast (E. M. Phizicky, et al., J. Biol. Chem. 261:2978-2986,1986). The yeast tRNA ligase can ligate substrates other than tRNAs, and has been shown to ligate the HAC1 mRNA, as mentioned above (C. Sidrauski, et al., supra, 1996; J. S. Cox and P. Walter, Cell 87:391-404, 1996). Both mammalian RNA ligase activities remain candidates for participation in the ligation of non-tRNA substrates in mouse cells. The efficiency and specificity of BHB-mediated splicing was estimated by competitive reverse transcription PCR. RNAs were obtained from NIH3T3 cells cotransfected with plasmids coding for reporter genes and plasmids coding for the endonuclease. The precursor and the spliced product were simultaneously amplified in a single PCR reaction. FIG. 11 shows that when NIH3T3 cells are transiently cotransfected with plasmids expressing pGFP-BHB and plasmids expressing Methanococcus jannaschii endonuclease (pOPTI-MJ or pMJ), an RT-PCR product derived from spliced mRNA appears. In contrast, no spliced EGFP RNA is produced in cells cotransfected with plasmids encoding the inactive enzyme (pMUT-MJ) or inactive substrate (pGFP-BHB+3). Splicing efficiency, assessed by a Phosphorimager, increases 10-fold when pOPTI-MJ is used instead of pMJ (FIG. 11C). FIG. 12 shows that when NIH3T3 cells are transiently cotransfected with a plasmid expressing GFPof and a plasmid expressing the M. jannaschii endonuclease, EGFP is produced. When a plasmid expressing an inactive endonuclease (pMUT-MJ) is used, EGFP is not produced. These results demonstrate that the M. jannaschii endonuclease can excise the intron and that an endogenous ligase activity can produce a spliced mRNA that is correctly translated. Fluorescence analysis substantiates a significant increase in the splicing efficiency when pOPTI-MJ is used instead of pMJ. To detect β-galactosidase expression via BHB-mediated splicing, NIH3T3 cells were cotransfected with both pBeta-GALof (FIG. 11) and pOPTI-MJ. The β-galactosidase activity does not differ significantly in cells cotransfected with the mutant enzyme (pMUT-MJ) or the control vector without an insert. In contrast, there was a 4- to 5-fold increase in β-galactosidase activity when the cells were cotransfected with pOPTI-MJ. A control experiment was carried out using a pCMV-β (a plasmid coding for the WT β-gal) instead of pBeta-GALof (G. R. MacGregor and C. T. Caskey, Nucleic Acids Res. 17:2365, 1989). WT β-galactosidase activity in cells cotransfected with pOPTI-MJ does not differ significantly from that in cells cotransfected with the mutant enzyme (pMUT-MJ) or with the empty vector (data not shown). These experiments confirm that a functional protein can be generated by BHB-mediated mRNA splicing. Since pBeta-GALof also contains a spliceosomal intron, we conclude that both spliceosomal and non-spliceosomal splicing can occur on the same RNA molecule. Finally, we designed RNA molecules that can form BHB substrates in trans with targeted mRNAs. A general scheme for a BHB-mediated trans splicing is shown in FIG. 13. This drawing shows the binding of a targeting mRNA, via Watson-Crick base pairing, to a target mRNA followed by MJ endonuclease cleavage and ligation by an endogenous ligase. We used as target a firefly luciferase mRNA characterized by the absence of the original AUG, and a targeting mRNA containing a functional 5′ UTR followed by a conventional start codon (FIG. 14A). Cotransfection of NIH3T3 cells with plasmids expressing these RNAs and the MJ endonuclease led to formation of RNA chimeras in which the target and the targeting RNA were recombined across the BHB. RT-PCR experiments demonstrate that both possible RNA recombinants were generated by the trans-splicing event (FIG. 14B). FIG. 14C shows that a defective firefly luciferase mRNA can be repaired by trans-splicing. It is essential that the two interacting RNA molecules form a bona fide BHB structure; if a classical double-stranded RNA is formed no trans-splicing occurs (FIGS. 14A and 14C). These experiments indicate that it is possible to reprogram a target pre-mRNA and, in principle, the possibility exists to achieve a therapeutic result such as correction of a mutation. Spliceosomal trans-splicing implies the interaction of an intron of one pre-mRNA with an intron of a second pre-mRNA, enhancing the recombination of splice sites between two conventional pre-mRNAs (M. Puttaraju, et al., Nat. Biotechnol. 17:246-252,1999). The various players within the spliceosome recognize the trans-splicing sequences in the targeting RNA rather than the corresponding sequences in the target RNA. A much simpler scenario characterizes BHB-mediated trans-splicing. The interaction to form the BHB in trans does not have to be limited to the introns, but can involve practically any region of the target and the players consist of only two proteins, the archaeal endonuclease and the endogenous ligase. Various approaches are currently being used to elucidate the principles that underlie the construction and function of eukaryotic cells and organisms. Some of these approaches, such as gene targeting (K. R. Thomas and M. R. Capecchi, Cell 51:503-512, 1987) or the gene trap technology (E. Medico, et al., Nat. Biotechnol. 19:579-582, 2001), operate at the level of the DNA. Others, like the Tet system, regulate gene expression at the level of transcription (U. Baron and H. Bujard, Methods Enzymol. 327:401-421, 2000). Yet another approach, such as induced dimerization, works at the protein level (D. M. Spencer, et al. Curr. Biol. 6:839-847, 1996). At the level of the DNA, in mouse, the choice strategy uses the Cre/lox P recombination system of bacteriophage PI (H. Gu, et al., Cell 73:1155-1164, 1993; H. Gu, et al., Science 265:103-106,1994). In this procedure a target gene is flanked with recombinase recognition (lox P) sites; coexpression in the same cell of the Cre recombinase results in the deletion of the lox-P flanked gene segment. The emergent strategy that we report here operates at the RNA level. This strategy also uses prokaryotic elements: the tRNA endonuclease/Bulge-Helix-Bulge (BHB) RNA cleavage system of Archaea. In murine cells, the production of functional RNA can be made dependent upon the presence of an archaeal endonuclease activity. The type of non-spliceosomal splicing described in this paper permits, in principle, conditional (in space and time) activation of inactive mRNA and mobilization of packets of RNA sequences to reprogram messenger RNAs. It can be used, for example, to repair genetically defective transcripts that contain loss-of-function. BHB-dependent cleavage and ligation is not limited to mRNA, but, in principle, could be applied to destroy, modify or restore the formation of regulatory non-coding RNA sequences such as mRNAs (M. Lagos-Quintana, et al. Curr. Biol. 12:735-739, 2002), Xist (A. Wutz, et al., Nat. Genet. 30:167-174, 2002) and Air RNAs (F. Sleutels, et al., Nature 415:810-813, 2002). Example 5 A. Plasmids Coding for mRNAs Containing the BHB Structure. GFPof was obtained by amplifying the EGFP gene from the pEGFP-N3 expression vector (Clontech). The EGFP was sequentially amplified with two sets of primers: P1 and P3, P2 and P3. A new start codon embedded in a Kozak sequence was inserted and the natural EGFP start codon was mutated with the introduction an AgeI site. The modified EGFP (GFPof) was re-inserted into the BglII-NotI sites of the pEGFP-N3 vector (pGFPof). Plasmids pGFPof+3 and pGFP-Stop were obtained by substitution of the EcoRI-AgeI fragment of pGFPof respectively with the double stranded oligonucleotides consisting of P4 and its complement and P5 and its complement. Plasmids pGFP-BHB and pGFP-BHB+3 contain the BHB in the 3′UTR. The EGFP gene was amplified using the primer pair P2 and P8 from the pd2EGFP-N1 vector (Clontech) to add a 35-nucleotide long spacer downstream of the stop codon. The P2-P8 PCR product was then submitted to a new round of PCR with the P2 and P6, P2 and P7 primer pairs, in order to add the BHB and BHB+3 structures, at the 3′ end of EGFP gene. These PCR products were digested with BglII and NotI and cloned back into the original vector. To obtain the Beta-GALof construct, a first PCR fragment containing the BHB domain was originated by amplification of pGFPof with oligonucleotides P9 and P47, and a second PCR fragment containing the altered ATG start of P-gal gene was obtained by amplification of pCMV-P (Clontech) with P45 and P46 primer pair. These two PCR products were mixed, and re-amplified using the oligonucleotides P9 and P46. The resulting fragment was restricted with BglII, blunt-ended by filling-in and then restricted with Earl. This was ligated to the β-galactosidase Earl-NotI restriction fragment, (from pCMV-β), to obtain Beta-GALof. The WT β-galactosidase gene was replaced by cloning the Beta-GALof sequence into the NotI sites of pCMV-β. B. Plasmids Coding for Methanococcus jannaschii tRNA Endonuclease. The M. jannaschii gene with the FLAG epitope at its 5′ end was cloned by PCR from the pET11 a bacterial expression vector (Hong Li, et al., Science 280:284, 1998, a kind gift of Dr. Christopher Trotta). The MJ-endoribonuclease PCR product was obtained using the primer pairs P 12 and P 13 and cloned in the Bg1II-NotI sites of the pd2EGFP-N1 backbone. The plasmid pMUT-MJ was obtained via PCR from pMJ. Three aminoacidic substitutions were introduced: His 125 to Phe, Lys 156 to Pro and Lys 157 to Gln. The M. jannaschii gene was amplified using three different primer pairs: P12 and P15, P14 and P17 and P16 and P13. The three PCR products were mixed, re-amplified with P12 and P13 and cloned in the Bg1II-NotI sites of the pd2EGFP-N1 backbone. OPTI-MJ template was obtained by assembling ten oligonucleotides (P20-P29). The OPTI-MJ gene was amplified, utilizing the Pfu DNA Polymerase (Stratagene) and the primers P12 and P3, and cloned in the Bg1II and NotI sites of the pd2EGFP-NI backbone. The plasmid pOPTI-MUT-MJ was obtained via PCR from pOPTI-MJ. Three aminoacidic substitutions were introduced: His 125 to Phe, Lys 156 to Pro and Lys 157 to Gln. The M. jannaschii gene was amplified using three different primer pairs: P12 and P31, P30 and P33, P32 and P3. The three PCR products were mixed, re-amplified with P12 and P3 and cloned in the pd2EGFP-N1 backbone. C. Plasmids Coding for Target and Targeting RNAs. The plasmid coding for target RNA (see FIG. 14) was obtained from pGL3 Control Vector (Promega). A sequence corresponding to one half of the BHB was inserted at the Hind III-NarI sites with consequent elimination of the AUG starting codon of the firefly luciferase gene. To synthesize the fragment to be inserted we amplified oligonucleotide P36 utilizing P34 and P35 as primers. The PCR product was digested with HindIII and NarI and cloned in pGL3 Control Vector (Promega). The plasmid coding for Targeting-1 RNA (see FIG. 14) was obtained from pcDNA3 (Invitrogen) by inserting at the BamHI-XhoI sites a double stranded fragment obtained by annealing P37 and P38 and subsequent digestion with BamHI-XhoI. The insert codes for an AUG, included in a Kozak sequence, followed by half BHB. The plasmid coding for Targeting-2 RNA (see FIG. 14) was obtained from pcDNA3 (Invitrogen) by inserting at the BamHI-XhoI sites a double stranded fragment obtained by annealing P39 and P40 and subsequent digestion with BamHI-XhoI. The insert codes for an AUG, included in a Kozak sequence, followed by a sequence complementary to the half BHB inserted in the target RNA. D. Culture Conditions and Cell Transfections. NIH3T3 fibroblasts were grown in Dulbecco's modified medium (DMEM) supplemented with 10% calf serum in a 37° C. incubator with 5% CO2. Cell transfections were carried out using the Lipofectamine 2000 or Lipofectamine Plus (Gibco-BRL) transfection reagent according to the manufacturer's instructions. Each transfection was performed in a 35 mm dish using 4 μg of total plasmid DNA with Lipofectamine 2000 or 2 μg with Lipofectamine Plus. E. RNA Preparation and RT-PCR Analysis. Total RNA was isolated from cells 24 hours after transfection using the Trizol reagent (Life Technologies) following the manufacturers instructions. 10 μg of total RNA were treated with 1 unit of RQ1 DNAse RNAse free (Promega M610A) for 30′ at 37° C. and phenol/chloroform extracted. Single stranded cDNA was obtained by poly-dT primed reverse transcription of 3 μg total RNA with SuperScript II RT (Life Technologies 18064-022). pGFPof, pGFPof+3 and pGFPof-stop mRNAs splicing analysis was performed by PCR using the primer pair P9 and P10, whereas the primer pair P11 and P3 was used for pGFP-BHB and pGFP-BHB+3 analysis. P9 or P3 primers were P32 labeled. PCR products were electrophoresed on a 6% polyacrylamide, 8M urea, 30% formamide gel. The gels were dried and exposed to Phosphorimager for 16 hours and visualized by STORM 860 Phosphorimager (Molecular Dynamics). cDNAs derived by trans-spliced mRNAs were submitted to 36 cycles PCR using Accuprime Taq DNA Polymerase System (Invitrogen) with the primer pair P41-P42 and P43-P44, and analyzed by agarose gel electrophoresis. F. Sequencing of RT-PCR Products. Spliced and unspliced amplified cDNAs were eluted from non-dried polyacrylamide denaturing gels and submitted to a new round of PCR. The P9-P10 primer pair was used for products derived from pGFPof, pGFPof+3 and pGFPof-stop mRNAs. P11-P3 was used for products derived from pGFP-BHB and pGFP-BHB+3. Sequence reactions were performed using the Bigdye Sequencing Kit (Perkin Elmer-Applied Biosystem) primed with P18 for products derived from the first plasmid group and with P19 for those derived from the second plasmid group. Sequences were analyzed on an ABI Prism 310 genetic analyser (Applied Biosystem). G. Visualization of EGFP Protein in Transfected Cells. Forty-eight hours after transfection, cells were fixed with 2% paraformaldehyde/0.1% Triton X100 for 20 minutes, incubated for 10 minutes with lug/ml Hoechst/PBS 1× solution and washed twice with PBS. All coverslips were mounted with 80% Glycerol/PBS mounting media. The images were taken by fluorescence microscopy (Olympus AX 70) with a Nikon digital camera (Coolpix 990) and processed with Adobe Photoshop version 5.0. H. Beta Galactosidase Assay. Forty-eight hours after Beta-GALof transfection, the cells were washed with phosphate-buffered saline and harvested in Passive Lysis Buffer (Promega). After two freeze-thaw cycles, the lysates were centrifuged and the supernatants were collected. β-gal activities were expressed as the ratio of reporter activity (β-galactosidase) to internal control activity (firefly luciferase). The β-galactosidase and luciferase activities were determined with the standard O-nitrophenil-D-galacto-pyranoside method (β-Gal Assay Kit, Invitrogen) and Luciferase Assay System (Promega), respectively. I. Luciferase Assay. To evaluate the trans-activation of the firefly luciferase gene, cells were transfected with a mixture of target and targeting plasmids. To normalize luciferase activity, the Renilla luciferase expression vector pRL (Promega) was added to the transfection mixture as control reporter. Forty-eight hours after transfection, the cells were washed with phosphate-buffered saline and harvested in Passive Lysis Buffer (Promega). After two freeze-thaw cycles, the lysates were centrifuged and the supernatants were collected. Luciferase activity was determined using the Dual Luciferase Reporter Assay System (Promega), according to manufacturer's instructions. The instrumentation used was a Lumat LB 9507 luminometer (EG & G Berthold). Example 6 The tRNA endonuclease of the archeobacterium Metahnococcus Jannaschii (MJ), when expressed in an eucaryotic organism, can be used to modulate gene expression at the post-transcriptional level. The endonuclease recognizes and splices RNA molecules when the latter have Bulge-Helix-Bulge (BHB) structures. Since the ends that the endonuclease creates are ligated by an endogenous RNA ligase, it is possible to activate, inactivate and fuse RNA molecules. Here we describe the creation of a line of transgenic mice that expresses the tRNA endonuclease of MJ in a manner that is constitutive in various tissues. BACKGROUND The tRNA endonuclease of Metahnococcus Jannaschii expressed in cell cultures recognizes and splices with a high specificity BHB structures that are inserted in a target mRNA, provoking the removal of small introns followed by the junction of RNA termini by an endogenous ligase. This intron-splicing process is independent of the spliceosomes. The endonuclease has the capacity to recognize and cut BHB structures even when the latter are created in trans or, in other words, by two distinct RNA molecules. Since the splicing reaction of a BHB in trans is followed by the joining of the termini to form hybrid RNA molecules, it is possible to construct plasmids that, when transfected in mammalian cells, will express “targeting” RNAs that are capable of forming, by way of a conventional coupling of complementary bases, a Bulge-Helix-Bulge structure in various “target” RNAs. This technology has been tested on cell models, using GFP and Firefly Luciferase as target genes (ref. The BHB-mediated splicing reactions have been evidenced by means of RT-PCR at the messenger RNA level and, in the case of Firefly Luciferase, by measuring gene reporter activity with the specific assay. In brief, the ability of the MJ tRNA endonuclease to recognize and splice BHB structures in trans allows one to design RNA molecules that, through a trans-splicing reaction, can modify endogenous RNAs without altering the genomic structure of the receiving organism. Given that this technology, which up to now has been applied to cell cultures, is potentially relevant to the modulation and analysis of genes, and to the correction of genetic defects in mouse models, and given that the creation of such technologies for the modification of specific RNA targets requires the use of animals that express the tRNA endonuclease of MJ, we created trangenic lines in which the gene that codifies for the enzyme had been inserted in the mouse genome. The sequence that codes for the endonuclease was modified so as to adapt it to the mouse codon usage, and then cloned downstream of a chicken beta actin promoter preceded by the CMV enhancer. The analysis of the expression levels of a typical transgene has shown that an adequate expression took place. Though the analysis carried out using RT-PCR has shown that expression occurred in all of the tissues examined (brain, heart, skeletal muscle, lung, kidney and liver), northern blot analysis has revealed appreciable levels of mRNA in the heart, muscle and, to a lesser extent, also in the liver. The expression of the transgene and the consequent production of the MJ endonuclease was further validated by means of immunoprecipitation and western blotting experiments (FIG. 15). The functionality of the enzyme produced in the tissues of transgenic mice was analyzed by assaying its activity in vitro on RNA substrates that contained BHB structures (FIG. 16). We also observed BHB-mediated splicing following delivery of naked plasmids, via the tail vein, in mice (FIG. 17). Results and Materials and Methods Creation of the Construct Before building the definitive construct, we created an intermediate one in order to endow the Metahnococcus Jannaschii tRNA endonuclease's coding sequence with the BGH's polyadenylization tail. To create that construct we resynthesized the entire coding sequence of the enzyme in accordance with the codon usage of mice. We also inserted the sequence that codes for the FLAG epitope at the enzyme's N-terminal extremity. The enzyme FLAG sequence was obtained from pOPTI-MJ (see patent XX) inserted in PUC18 as a NheI-BamHI fragment (pUC-MJ). Downstream of the MJ coding sequence, we inserted the BGH's polyadenylization tail. The latter was obtained by way of amplification with the BGH1 and BGH2 primers from the pcDNA3 plasmidic vector. The fragment thus produced was digested with the BamHI and XbaI restriction enzymes and cloned in the BamHI and XbaI sites of pUCMJ. The MJ-BGHpA fusion was then excised by digestion with the BglI enzyme and cloned in the polylinker of the commercial vector pTriEX-1.1 Neo (Novagen) digested with the restriction enzyme BglII. In the construct thus obtained (pTriEX-MJ), the MJ endonuclease is under the control of the chicken beta actin promoter preceded by the human CMVie enhancer. PTrieX-MJ was linearized with the XhoI enzyme and then injected in mouse oocytes. BGH1 5′- ttg acg agt tct tctgaggggatccat tcctag agctcgctg atcagcc-3′ BGH2 5′- agg acc tct aga aga tct gcc tgc tat tgt ctt ccc a-3′ Injection in the Oocytes The oocytes were injected with a solution containing the construct linearized with the XhoI enzyme at a concentration of 2-5 ng/μl, transferred in the XX terrain, maintained in culture for xx, and reimplanted in pseudopregnant FVB/N females. Four transgenic founders were identified by PCR on DNA extracted from the tails (primers MJ1 and MJ2). (The amplified product is 693 bp on genomic DNA). MJ1 5′- CTC TGA CTG ACC GCG TTA CTC-3′ MJ2 5′-TGC CGT TCT TGT CGA ACA CG-3′ Characterization by Means of Southern Blotting The genomic DNA was extracted from the tail of each founder and results were confirmed using DNA extracted from the brain and liver of transgenic F1 mice (obtained from the re-crossing founder X FVB/N). Extraction was carried out using the salting out method (ref. Miller, S. A., et al., NAR 6(3):1215, 1988). The DNA thus obtained was digested with the BglII, NheI and AflI enzymes, electrophoresed and transferred on Hybond N+ (Hamersham). Filters were hybridized with a base probe specific for optimized Methanococcus Jannaschii that was obtained by digesting pTrieX-MJ with BglII. Analysis of Transgene Expression All transgenes were analyzed for their expression by means of southern blotting. The RNAs were obtained from the liver, heart, skeletal muscle, lung, spleen, brain and kidney. The organs were taken from mice that resulted from the third re-crossing with FVB/N and two mice were analyzed for each transgene. 30 μg of total RNA from each tissue were gel electrophoresed and blotted on Hybond N+ according to the protocol provided by the supplier. The northern blots that were obtained were hybridized with the MJ probe (BglII fragment). Only mice derived from MJ1224 yielded a positive signal in the lanes corresponding to the heart, skeletal muscle, brain and liver. The RNAs derived from MJ1224 mice were also analyzed by means of RT-PCR using MJ1 and MJ2 primers. Those primers amplify a 435 bp fragment on cDNA. RT-PCR analysis showed some expression, albeit a minimal one, also in those tissues that had yielded negative results upon northern blotting testing. Referring to FIG. 15A, northern blotting analysis of the expression of the archaeal endonuclease in various tissues of the transgenic mouse is demonstrated. Immunopurification The tRNA endonuclease of MJ was purified from a homogeneous mixture of heart, skeletal muscle and liver obtained from two transgenic mice (F1) by means of immunopurification on anti-FLAG monoclonal antibodies combined with agarose (Ezview Red ANTI-FLAG M2 Affinity Gel, Sigma). The homogenous mixture contained 450 mg of liver and the entire heart in a lysis buffer according to the protocol suggested by the producer of the resin. The entire lysate obtained from the transgenic mouse tissue and FVB/N was incubated with 40 μg of resin O/N at 4° C. The enzyme was eluted for competition with the 3× FLAG peptide according to instructions. The entire eluate was utilized for the in vitro assay. Referring to FIG. 15B, the enzyme is prevalently expressed in the heart and in the skeletal muscle. Immunopurification and western blotting of the archaeal enzyme from liver and skeletal muscle are also demonstrated. The control, immunopurification and western blotting of the archaeal enzyme and of FLAG-GFPof from NIH3T3 cells cotranfected with plasmids coding for the two proteins, is also disclosed. Functional Assay on BHB Substrates The tRNA endonuclease of MJ was purified by immunoprecipitation from the heart, muscle and liver. As a negative control, the same procedure was repeated on FVB/N mice. As a positive control, a purified and dialyzed recombinant MJ endonuclease produced from the bacterial strain (Trotta) was employed. The substrate that was used for the enzymatic in vitro assay is represented by a RNA marked by means of in vitro transcription with αUTP32, which represents a BHB structure recognized by the enzyme. The precursor was incubated for 3 hours at 37° C. after addition to the total resin eluate, which corresponded to 100 μl, of 50 μl JB70 buffer (NH4Cl 70 mM, MgCl2 7 mM, EDTA 0.1 mM, DTT 2.5 mM, Glycerol 10%) and 30 fmoles of substrate (1 μl). As a positive control, 2 μl of purified MJ, corresponding to a total of 0.4 μl, were utilized. At the end of the enzymatic assay, the samples (RNA) were extracted with phenol and precipitated in ethanol utilizing a tRNA carrier. After having been resuspended in RNA MIX buffer (Urea, Sucrose, 0.5% BBF, 0.5% XFF, TBE 10×), the samples were run on a 12% acrylamide 8M urea gel. The result was analyzed using STORM 860 (Molecular Dynamics). Results FIGS. 15, 16 and 17 summarize results obtained from the above-described experiments. FIG. 16A discloses functional analysis of the archaeal tRNA endonuclease obtained from the transgenic mouse. FIG. 16B shows the structure and sequence of the substrate utilized in the assay. FIG. 17 illustrates a luminescence analysis of hepatic tissue lysates obtained from mice that were injected in the tail vein. The archaeal enzyme and the endogenous lysate produce a spliced messenger coding for luciferase. Referring to FIG. 17, pOMJ: The mice were injected with a naked plasmid coding for the archaeal endonuclease. pMUT-OMJ: The mice were injected with a naked plasmid coding for the mutant archaeal endonuclease. pGL3: The mice were injected with a naked plasmid coding for wild-type firefly luciferase (Promega). pLUCof, pMUT-OMJ: The mice were co-injected with a naked plasmid coding for LUCof mRNA (this RNA contains an archaeal intron that renders the latter out of frame) and a naked plasmid coding for the mutant enzyme. PLUCof, pOMJ: The mice were co-injected with a naked plasmid coding for LUCof mRNA (excision of the intron and ligation of the exons results in the production of a functional luciferase mRNA) and a naked plasmid coding for the archaeal enzyme. Twenty μg of the indicated naked plasmid were injected in 1, 2, and 3. Twenty μg of plasmid coding for the archaeal enzyme or its mutant version and 20 μg of a plasmid coding for pLUCof were injected in the tail vein of mice in 4 and 5. TABLE 2 Oligodeoxyribonucleotides P1 5′-GAGCTCAAGCTTCGAATTCCCGGTCGTGACTCCAGAGGCTTACACCGGAGATATCACGACCGGTTGTGAGCAAGGGCGAG-3′ P2 5′-ATCACGAGATCTCCACCATGGACTACAAAGACGATGACGATAAACTCGAGCTCAAGCTTCGAATT-3′ P3 5′-TCGGGATCCTCTACAAATGTGGTATGGCTG-3′ P4 5′-GCTTCGAATTCCCGGTCGTGACTTCTCCAGAGGCTTACACCGGAGAAGATATCACGACCGGTTGTGA-3′ P5 5′-GCTTCGAATTCCCGGTCGTGACTCCAGAGGTAACTGACTAAACCGGAGATATCACGACCGGTTGTGA-3′ P6 5′-ATAAGAATGCGGCCGCCCGGTCGTGATATCTCCGGTGTAAGCCTCTGGAGTCACGACCGGGGACGGG-3′ P7 5′-ATAAGAATGCGGCCGCCCGGTCGTGATATCTTCTCCGGTGTAAGCCTCTGGAGAAGTCACGACCGGGGACGGG-3′ P8 5′-TCACGACCGGGGACGGGGGCCCAGACGGAGGGCGAGTCCTTGTAGCGCATCTACACATTGATCCTAGCAGA-3′ P9 5′-CGTCAGATCCGCTAGCGCTAC-3′ P10 5′-CGTCGCCGTCCAGCTCGACCA-3′ P11 5′-TAGATGCGCTACAAGGACTCG-3′ P12 5′-ATCACGAGATCTCCACCATGGACTACAAAGACGATGACGATAAAATGGTGAGAGATAAAATG-3′ P13 5′-ATAAGAATGCGGCCGCGGATCCTTATGGTTTTACATAGG-3′ P14 5′-ATAAAGAATTCTCTGTTTATTTGGTTAAGG-3′ P15 5′-AACAGAGAATTCTTTATCATGTTAGCTCC-3′ P16 5′-TCAGTTCGGCCGCAATTACTCATAGCAATC-3′ P17 5′-GTAATTGCGGCCGAACTGAGTGAGCAACC-3′ P18 5′-GGCACCACCCCGGTGAACAG-3′ P19 5′-GTATGGCTGATTATGATCTAG-3′ P20 5′-GACTCAGATCTCCACCATGGACTACAAAGACGATGACGATAAAGCCGGCAGAGATAAAATGGGCAAGAAGATCACCGGT-3′ P21 5′-GGCGCTCAGCTTGCTGATGCCGTTCTTGTCGAACACGATCACTCTGTCGCCGTCCAGCAGACCGGTGATCTTCTTGCCCAT-3′ P22 5′-GGCATCAGCAAGCTGAGCGCCAGGCACTATGGCAATGTGGAAGGCAATTTCCTGAGCCTGAGCCTGGTGGAAGCCCTGTAC-3′ P23 5′-TTCGAAGCTCAGGGGCTTGTTGTCCTTATACTTCACCTCCAGCCAGCCCAGGTTGATCAGGTACAGGGCTTCCACCAGGCT-3′ P24 5′-AACAAGCCCCTGAGCTTCGAAGAGCTGTATGAATATGCCAGGAACGTGGAGGAAAGACTGTGTCTGAAGTACCTGGTGTAT-3′ P25 5′-GAAGTCGGCGCCATACTTCAGGCCGGTCTTCACGATATAGCCCCTGGTCCTCAGGTCCTTATACACCAGGTACTTCAGACA-3′ P26 5′-CTGAAGTATGGCGCCGACTTCAGACTGTACGAAAGGGGCGCCAACATCGACAAGGAGCACAGCGTGTATCTGGTGAAGGTG-3′ P27 5′-GTGGGCCACTCTCACGAAGCCGGTCAGCTCGCTCAGCAGGAAGCTGCTGTCTTCAGGGAACACCTTCACCAGATACACGCT-3′ P28 5′-GGCTTCGTGAGAGTGGCCCACAGCGTGAGAAAGAAGCTGCTGATCGCCATCGTGGACGCCGACGGCGACATCGTGTATTAC-3′ P29 5′-CCTCTACAAATGTGGTATGGCTGCTACGCGGCCGCGGATCCTTAAGGCTTCACATAGGTCATATTGTAATACACGATGTCGCCG TC-3′ P30 5′-ATCGACAAGGAGTTCAGCGTGTATCTGGTG-3′ P31 5′-CAGATACACGCTGAACTCCTTGTCGATGTT-3′ P32 5′-GCCCACAGCGTGAGACCTCAGCTGCTGATCGCCATC-3′ P33 5′-GATGGCGATCAGCAGCTGAGGTCTCACGCTGTGGGC-3′ P34 5′-TAGGGAAGCTTCGTCAGATCCGCTAGCGC-3′ P35 5′-AGAATGGCGCCGGGCCTTTCTTTATGTTTTTGGCGTC-3′ P36 5′-CGTCAGATCCGCTAGCGCTACCGGACTCAGATCAATTCGCTGACTAGCCCGGAGATATCCTGGACCGGTTGAAGACGCCAAAAA CATAAAG-3′ P37 5′-GATCTGGATCCACCATGGTCCGGTCCAGGACTCCAGAGGGCTAGTCACTCGAGATCTA-3′ P38 5′-TAGATCTCGAGTGACTAGCCCTCTGGAGTCCTGGACCGGACCATGGTGGATCCAGATC-3′ P39 5′-GATCTGGATCCACCATGGTCCGGTCCAGGATATCTCCGGGCTAGTCACTCGAGATCTA-3′ P40 5′-TAGATCTCGAGTGACTAGCCCGGAGATATCCTGGACCGGACCATGGTGGATCCAGATC-3′ P41 5′-CCCACTGCTTACTGGCTTATCG-3′ P42 5′-CCCATACTGTTGAGCAATTCACG-3′ P43 5′-TGAGCTATTCCAGAAGTAGTG-3′ P44 5′-GGGAGTGGCACCTTCCAGGGTC-3′ P45 5′-GATATCACGACCGGTTTCGTTTACTTTGACCAACAAGA-3′ P46 5′-TTCAGGCTGCGCAACTGTTGG-3′ P47 5′-TCTTGTTGGTCAAAGTAAACGAAACCGGTCGTGATATC-3′ REFERENCES Abelson, J., “RNA processing and the intervening sequence problem,” Annu. 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C., “Many of the conserved nucleotides of tRNAPhe are not essential for ternary complex formation and peptide elongation,” EMBO J. 13:2464-2471 (1994). Otsuka, A., De Paolis, A and Tocchini-Valentini, G. P., “Ribonuclease “XIaI”, an activity from Xenopus laevis oocytes that excises intervening sequences from yeast transfer ribonucleic acid precursors,” Mol. Cell. Biol. 1:269-280 (1981). Pan, T. and Uhlenbeck, O. C., “A small metalloribozyme with a two step mechanism,” Nature 358:560-563 (1992). Perkins, K. K., Furneaux, H. and Hurwitz, J., “Isolation and characterization of an RNA ligase from HeLa cells,” Proc. Natl. Acad. Sci. USA 82:684-688 (1985). Phizicky, E. M., Schwartz, R. C. and Abelson, J., “Saccharomyces cerevisiae tRNA ligase. Purification of the protein and isolation of the structural gene,” J. Biol. Chem. 261:2978-2986 (1986). Puttaraju, M, Jamison, S. F., Mansfield, S. G., Garcia-Blanco, M. A. and Mitchell, L. 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D. and Daniels, C. J., “Recognition of exon-intron boundaries by the Halobacterium volcanii tRNA intron endonuclease,” J. Biol. Chem. 265:18104-18111 (1990). Thomas, K. R. and Capecchi, M R., “Site-directed mutagenesis by gene targeting in mouse embryo-derived stem cells,” Cell 51:503-512 (1987). Tinoco, I., Jr., Borer, P. N., Dengler, B., Levine, M., Uhlenbeck, O. C., Crothers, D. M. and Gralla, J., “Improved estimation of secondary structure in RNAs,” Nature New Biol. 246:40-41 (1973). Trotta, C. R., Miao, F., Arn, E. A., Stevens, S. W., Ho, C. K., Rauhut, R. and Abelson, J. N., “The yeast tRNA splicing endonuclease: a tetrameric enzyme with two active site subunits homologous to the Archeal tRNA splicing endonculeases,” Cell (accompanying paper). Tuerk, C. and Gold, L., “Systematic evolution of ligands by Exponential enrichment: RNA ligands to bacteriophage T4 DNA polymerase,” Science 249:505-510 (1990). Westaway, S. K. and Abelson, J., “Splicing of tRNA Precursors. In tRNA: Structure, Biosynthesis, and Function,” D. Soll and U. L. RajBhandary, eds (Washington, D.C.: ASM Press), pp. 79-92 (1995). Wrede, P., Wurst, R., Vournakis, J. and Rich, A., “Conformational changes of yeast tRNAPhe and E. coli tRNAGlu as indicated by different nuclease digestion patterns,” J. Biol. Chem. 254:9608-9616 (1979). Wutz, A., Rasmussen, T. P. and Jaenisch, R., “Chromosomal silencing and localization are mediated by different domains of Xist RNA,” Nat. Genet. 30:167-174 (2002). | <SOH> BACKGROUND OF THE INVENTION <EOH>Accuracy in tRNA splicing is essential for the formation of functional tRNAs and, hence for gene expression. In Bacteria, tRNA introns are self-splicing group I introns and the splicing mechanism is autocatalytic. In Eukarya, tRNA introns are small and invariably interrupt the anticodon loop one base 3′ to the anticodon. In Archaea, the introns are also small and often reside in the same location as eukaryal tRNA introns. In both Eukaryotes and Archaea, the specificity for recognition of the pre-tRNA resides in the endonucleases. These enzymes remove the intron by making two independent endonucleotytic cleavages. The archaeal enzyme acts without any reference to the mature domain (mature-domain independent mode, MDI) but instead recognizes a structure, the bulge-helix-bulge (BHB) motif, that defines the intron-exon boundaries. The eukaryal enzyme normally acts in a mature-domain dependent mode (MDD); the enzyme recognizes a tripartite set of RNA elements. One subset of recognition elements is localized in the mature domain, while two other subsets are localized at the exon-intron boundaries. A pivotal role is played by a base-pair located near the site of 3′ cleavage, the so-called anticodon-intron pair (A-I pair). A purine is strongly preferred at the position preceding the 5′ cleavage site. The primary and secondary structures at the exon-intron junctions of the archaeal and eukaryal pre-tRNAs do not show evident similarities, with the exception of the three-nucleotide bulged structure, closed by the A-I pair and containing the 3′ cleavage site, that resembles half of the BHB. The endonuclease are evolutionarily related, but their substrate recognition properties appear drastically different. It has previously been shown, however, that the Xenopus and the yeast endonucleases retain the ability to operate in the MDI mode. | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>In one embodiment, the present invention is a method of cleaving a target RNA molecule comprising the step of exposing in vitro or in vivo the target molecule to an eukaryotic tRNA splicing endonuclease, wherein the target molecule is in the bulge-helix-bulge conformation, wherein cleavage occurs within the bulge-helix-bulge and cleavage products are generated, and wherein the target molecule does not comprise a tNRA structure. In a preferred embodiment, the bulge-helix-bulge conformation is obtained by hybidizing the target RNA with an oligonucleotide designed to form a bulge-helix-bulge conformation. In another preferred embodiment, the bulge-helix-bulge conformation is obtained by hybridizing the target RNA with a second RNA wherein the hybridized target RNA and second RNA form a bulge-helix-bulge conformation. In other embodiments, the target molecule is an mRNA molecule and the oligonucleotide comprises either an RNA molecule, a DNA molecule or a molecule wherein at least one nucleotide is not a ribonucleotide. In another embodiment, the present invention is a method of cleaving a target RNA molecule comprising the step of exposing the target molecule in a cell to heterologous archeael tRNA splicing endonuclease, wherein the target molecule is in the bulge-helix-bulge conformation, wherein cleavage occurs between the second and third nucleotides at the bulges and cleavage products are generated, and wherein the target molecule does not comprise a tRNA structure. Preferably, the bulge-helix-bulge conformation is created by two mRNA molecules, wherein the two mRNA molecules are the target RNA molecule and a second RNA molecule and additionally comprises the step of ligation of cleavage products from the target RNA and the second RNA, wherein a fusion RNA is formed comprising at least one cleavage product from the first target RNA molecule and at least one cleavage product from the second target RNA molecule. This invention is also a method for recombining a target RNA molecule that is in the bulge-helix-bulge (BHB) conformation with an exogenous, or targeting, RNA molecule. As described above, the target RNA molecule has been shown to be cleaved within the bulge-helix-bulge. When the cleaved target RNA molecule and the exogenous RNA molecule are exposed to an appropriate ligase, RNA chimeras form, recombining the target RNA molecule and the exogenous RNA molecule across the bulge-helix-bulge. The method of the present invention can be used for recombining RNA molecules that can be used for altering RNA function. The recombination may be used to destroy RNA function, modify RNA, or even restore RNA function. In another embodiment, the endonuclease, preferably the tRNA endonuclease of the archeobacterium Metahnococcus Jannaschii (MJ), when expressed in an eucaryotic organism can be used to modulate gene expression at the post-transcriptional level. The endonuclease recognizes and splices RNA molecules when the latter have Bulge-Helix-Bulge (BHB) structures. Since the ends that the endonuclease creates are ligated by an endogenous RNA ligase, it is possible to activate, inactivate and fuse RNA molecules. In another embodiment, the invention is a line of transgenic mice that expresses a heterologous tRNA endonuclease in a manner that is constitutive in various tissues. Other features, objects and advantages of the present invention will be apparent to one of skill in the art after review of the specification and claims. | 20040409 | 20130820 | 20050224 | 57985.0 | 0 | SHIN, DANA H | Method of RNA cleavage and recombination | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,821,892 | ACCEPTED | Hysteresis circuits used in comparator | A hysteresis circuit for use in a comparator having a first and a second transistors as an input stage and a constant current source. The hysteresis circuit comprises a first resistor disposed between a source of the first transistor and the constant current source and a second resistor disposed between a source of the second transistor and the constant current source, and comprises a first and a second current generating means. The first current generating means supplies a current to the source of the first transistor and derives a current out from the source of the second transistor if an output signal of the comparator is a first logic value, while the second current generating means supplies a current to the source of the second transistor and derives a current out from the source of the first transistor if the output signal of the comparator is a second logic value. | 1. A hysteresis circuit for a comparator, said comparator comprising an input stage including a first transistor and a second transistor, each having a gate terminal serving as one of two input terminals of said comparator to receive one of two input signals, said comparator further comprising a constant current source connected to supply a constant current to said input stage of said comparator, said hysteresis circuit comprising: a first resistor element coupled between a source terminal of said first transistor and said constant current source of said comparator; a second resistor element coupled between a source terminal of said second transistor and said constant current source of said comparator; a first current generating means for supplying a first current to said source terminal of said first transistor and deriving a forth current out from said source terminal of said second transistor when an output signal from an output terminal of said comparator is a first logic value; and a second current generating means for supplying a third current to said source terminal of said second transistor and deriving a second current out from said source terminal of said first transistor when said output signal from said output terminal of said comparator is a second logic value. 2. The hysteresis circuit for a comparator of claim 1, wherein said first to said forth currents have the same current value. 3. The hysteresis circuit for a comparator of claim 1, wherein said first to said forth currents are equal to the constant current produced by said constant current source of said comparator. 4. The hysteresis circuit for a comparator of claim 1, wherein said first resistor element and said second resistor element have the same resistance value. 5. The hysteresis circuit for a comparator of claim 1, wherein said first transistor and said second transistor are PMOS transistors. 6. The hysteresis circuit for a comparator of claim 1, wherein said first to said forth currents have the same current value, wherein said first resistor element and said second resistor element have the same resistance value, and wherein a single-side hysteresis width generated by said hysteresis circuit for said comparator is equal to said current value multiplied by twice said resistance value while a double-side hysteresis width generated by said hysteresis circuit for said comparator is equal to twice the single-side hysteresis width. 7. A hysteresis circuit for a comparator, said comparator comprising an input stage including a first transistor and a second transistor, each having a gate terminal serving as one of two input terminals of said comparator to receive one of two input signals, said comparator further comprising a constant current source connected to supply a constant current to said input stage of said comparator, said hysteresis circuit comprising: a first resistor element coupled between a source terminal of said first transistor and said constant current source of said comparator; a second resistor element coupled between a source terminal of said second transistor and said constant current source of said comparator; a switching means including a first switch element, a second switch element, a third switch element and a forth switch element, said switching means being controlled that said first switch element and said forth switch element are ON and said second switch element and said third switch element are OFF if an output signal from an output terminal of said comparator is a first logic value, and that said first switch element and said forth switch element are OFF and said second switch element and said third switch element are ON if said output signal from said output terminal of said comparator is a second logic value; a first constant current source element for selectively supplying a constant current to said source terminal of said first transistor through said first switch element; a second constant current source element for selectively deriving a constant current out from said source terminal of said first transistor through said second switch element; a third constant current source element for selectively supplying a constant current to said source terminal of said second transistor through said third switch element; and a forth constant current source element for selectively deriving a constant current out from said source terminal of said second transistor through said forth switch element. 8. The hysteresis circuit for a comparator of claim 7, wherein the constant currents produced by said first to said forth constant current source elements have the same current value. 9. The hysteresis circuit for a comparator of claim 7, wherein the constant currents produced by said first to said forth constant current source elements are equal to the constant current produce by said constant current source of said comparator. 10. The hysteresis circuit for a comparator of claim 7, wherein, said first resistor element and said second resistor element have the same resistance value. 11. The hysteresis circuit for a comparator of claim 7, wherein, said first transistor and the second transistor are PMOS transistors. 12. The hysteresis circuit for a comparator of claim 7, wherein the constant currents produced by said first to said forth constant current source elements have the same current value, wherein said first resistor element and said second resistor element have the same resistance value, and wherein a single-side hysteresis width generated by said hysteresis circuit for said comparator is equal to said current value multiplied by twice said resistance value while a double-side hysteresis width generated by said hysteresis circuit for said comparator is equal to twice the single-side hysteresis width. 13. A hysteresis circuit for a comparator, said comparator comprising an input stage including a first transistor and a second transistor, each having a gate terminal serving as one of two input terminals of said comparator to receive one of two input signals, said comparator further comprising a constant current source connected to supply a constant current to said input stage of said comparator, said hysteresis circuit comprising: a first and a second resistor elements having the same resistance value, said first resistor element being coupled between a source terminal of said first transistor and said constant current source of said comparator, and said second resistor element being coupled between a source terminal of said second transistor and said constant current source of said comparator; a first to a forth constant current source elements, each for producing a constant current having the same current value as the constant current produced by said constant current source of said comparator; a first switch element coupled between said first constant current source element and said source terminal of said first transistor so that said first constant current source element selectively supplies a constant current to said source terminal of said first transistor; a second switch element coupled between said second constant current source element and said source terminal of said first transistor so that said second constant current source element selectively derives a constant current out from said source terminal of said first transistor; a third switch element coupled between said third constant current source element and source terminal of said second transistor so that said third constant current source element selectively supplies a constant current to said source terminal of said second transistor; a forth switch element coupled between said forth constant current source element and said source terminal of said second transistor so that said forth constant current source element selectively derives a constant current from said source terminal of said second transistor; and a switch element control means for controlling ON/OFF operations of said first to said forth switch elements so that said first switch element and said forth switch element are ON and said second switch element and said third switch element are OFF if an output signal from an output terminal of said comparator is a first logic value and that said first switch element and said forth switch element are OFF and said second switch element and said third switch element are ON if said output signal from said output terminal of said comparator is a second logic value. 14. The hysteresis circuit for a comparator of claim 13, wherein a single-side hysteresis width generated by said hysteresis circuit for said comparator is equal to said current value of said constant current multiplied by twice said resistance value of said resistor elements while a double-side hysteresis width generated by said hysteresis circuit for said comparator is equal to twice the single-side hysteresis width. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic circuit, and particularly, to a circuit for providing hysteresis in a differential input comparator. 2. Description of the Related Art A typical comparator is provided with two input terminals for comparing an input voltage signal and a reference voltage signal respectively received at the two input terminals, amplifying the voltage difference between the two signals and then producing an output signal with a logic high voltage or a logic low voltage based on the voltage difference. Generally, a logic high signal is produced at the output of the comparator when the input voltage is higher than the reference voltage. On the other hand, a logic low signal is produced at the output of the comparator when the input voltage is lower than the reference voltage. In order to prevent erroneous changes in the output voltage of the comparator resulting from noises in the input voltage signal or in the reference voltage signal, a typical solution to provide a hysteresis circuit in the comparator, so that a threshold voltage at which the output voltage of the comparator changes from logic low to logic high is different from a threshold voltage at which the output voltage of the comparator changes from logic high to logic low. FIG. 1 is a graph showing the relation between the input voltage signal and the output voltage signal of a comparator with a hysteresis characteristic, in which the horizontal axis represents the input voltage signal Vin while the vertical axis represents the output voltage signal Vout. When the output voltage signal Vout is in a logic low state, the input voltage signal Vin must rise above an upper threshold voltage Vth so that the output voltage signal Vout will change from logic low to logic high. When the output voltage signal Vout is in a logic high state, the input voltage signal Vin must fall below a lower threshold voltage Vtl so that the output voltage signal Vout will change from logic high to logic low. The voltage difference between the upper threshold voltage Vth and the lower threshold voltage Vtl is referred to as a hysteresis width, which is usually designed to be several hundreds of Millivolts. R.O.C. Patent Publication No. 508567, titled “Hysteresis comparing device with constant hysteresis width” discloses a comparator circuit having a hysteresis characteristic. FIG. 2 illustrates a schematic circuit diagram of the hysteresis comparing device disclosed in the above patent. As shown in FIG. 2, the hysteresis comparing device 20 comprises a threshold voltage generator 22, a selection switching device 24 and a comparator 26. The hysteresis comparing device 20 receives an input voltage signal Vin and produces an output voltage signal Vout. The threshold voltage generator 22 generates an upper threshold voltage Vth and a lower threshold voltage Vtl from a DC voltage signal Vdc according to a desired hysteresis width. The selection switching device 24 includes a first switch 24a and a second switch 24b, which are controlled on the basis of the output voltage signal Voutof the comparator 26 to select one of the upper threshold voltage Vth and the lower threshold voltage Vtl as a reference voltage signal of the comparator. When the output voltage signal Vout is in a logic low state, the switch 24a is turned ON while the switch 24b is turned OFF, and thus the upper threshold voltage Vth is output from the selection switching device 24. On the other hand, when the output voltage signal Vout is in a logic high state, the switch 24a is turned OFF while the switch 24b is turned ON, and thus the lower threshold voltage Vtl is output from the selection switching device 24. According to the above design, when the output voltage signal Vout is in a logic low state, the input voltage signal Vin must rise above the upper threshold voltage Vth so that the output voltage signal Vout will change from logic low to logic high; when the output voltage signal Vout is in a logic high state, the input voltage signal Vin must fall below the lower threshold voltage Vtl so that the output voltage signal Vout will change from logic high to logic low. Thereby, the hysteresis effect is achieved. However, the prior art circuit in FIG. 2 is designed by providing an external threshold voltage generating circuit to a comparator to thereby obtain a hysteresis effect, which is disadvantageous because of its slow switching rate and the complicated circuit components. Such a comparing device is impossible to be designed into an integrated circuit. Therefore, it is desired to develop comparator hysteresis circuit, which is fast in switching rate, simple in circuit structure and suitable for application in an integrated circuit. SUMMARY OF THE INVENTION The object of the present invention is to provide a hysteresis circuit for a comparator, which is disposed in the comparator circuit and has the advantages of fast switching rate, simple structure and fewer components. Another object of the present invention is to provide a hysteresis circuit for a comparator, which is configured only by current source elements and resistor elements and thus is suitable for use in an integrated circuit to provide a hysteresis width insensible to variations of the power supply voltage and the temperature. The hysteresis circuit according to the present invention may be employed in a differential comparator having a differential input stage including a first transistor and a second transistor. Each of the first transistor and the second transistor has a gate terminal serving as one of two input terminals of the comparator. The comparator further includes a constant current source for supplying a constant current to the differential input stage of the comparator. The hysteresis circuit of the present invention comprises a first and a second resistor elements, a first to a forth constant current source elements anda first to a forth switch elements, all disposed in the above comparator. Both the first and the second resistor elements have the same resistance value. The first resistor element is coupled between a source terminal of the first transistor and the constant current source element of the comparator, while the second resistor element is coupled between a source terminal of the second transistor and the constant current source element of the comparator. Each of the first to the forth constant current source elements produces a constant current, which is of the same value as the current produced by the constant current source of the comparator. The first switch element is coupled between the first constant current source element and the source terminal of the first transistor so that the first constant current source element selectively supplies a constant current to the source terminal of the first transistor. The second switch element is coupled between the second constant current source element and the source terminal of the first transistor so that the second constant current source element selectively derives a constant current out from the source terminal of the first transistor. Symmetrically, the third switch element is coupled between the third constant current source element and the source terminal of the second transistor so that the third constant current source element selectively supplies a constant current to the source terminal of the second transistor. Similarly, the forth switch element is coupled between the forth constant current source element and the source terminal of the second transistor so that the forth constant current source element selectively derives a constant current out from the source terminal of the second transistor. ON/OFF operations of the first to the forth switch elements are controlled based on a signal from the output terminal of the comparator. If the signal from the output terminal of the comparator is a first logic value, then the first and the forth switch elements are turned ON while the second and the third switch elements are turned OFF. If the signal from the output terminal of the comparator is a second logic value, then the first and the forth switch elements are turned OFF while the second and the third switch element are turned ON. With the above configuration according to the present invention, a single-side hysteresis width equal to the current value I of the constant current source element multiplied by twice the resistance value R of the resistor element, i.e., a double-side hysteresis width equal to twice the single-side hysteresis width, can be provided. BRIEF DESCRIPTION OF THE DRAWINGS Objects and advantages of the present invention will be fully understood from the detailed description to follow taken in conjunction with the embodiments as illustrated in the accompanying drawings, wherein: FIG. 1 is a graph showing the changes in an output voltage of a comparator with a hysteresis characteristic; FIG. 2 depicts a schematic circuit diagram of a conventional hysteresis comparing device; FIG. 3 is a graph showing the changes in output voltage of a comparator employing the hysteresis circuit according to the present invention; FIG. 4 depicts a schematic circuit diagram of a comparator employing the hysteresis circuit according to the present invention; FIGS. 5(a) and 5(b) are circuit diagrams explaining the operations of the comparator as the output signal changes from logic low to logic high; and FIGS. 6(a) and 6(b) are circuit diagrams explaining the operations of the comparator as the output signal changes from logic high to logic low. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 4, a circuit diagram of a comparator employing the hysteresis circuit according to the present invention is shown. It should be noted that, for simplicity, only components associated with the hysteresis circuit, instead of complete circuit components, are illustrated in the circuit diagram in FIG. 4. As shown, a differential input comparator is provided with an input stage, including a first PMOS transistor Q1 and a second PMOS transistor Q2. The first PMOS transistor Q1 and the second PMOS transistor Q2 are two PMOS transistors with substantially the same characteristics, and the gate terminals thereof are respectively used as two input terminals of the comparator to respectively receive a first input signal Vin+ and a second input signal Vin−. The comparator further comprises a constant current source (the fifth constant current source) I5 for producing a constant current of “I”, which is supplied to the input stage of the comparator. Moreover, the comparator has an output terminal (not shown) for outputting an output signal Vout, which is generated based on a voltage difference ΔV between the first input signal Vin+ and the second input signal Vin−. According to the hysteresis circuit for a comparator of the present invention, a first resistor R1, a second resistor R2, a first constant current source I1, a second constant current source I2, a third constant current source I3, a forth constant current source I4, a first switch SW1, a second switch SW2, a third switch SW3 and a forth switch SW4 are provided in the differential input comparator. The first resistor R1 and the second resistor R2 are series coupled between a source terminal S1 of the first PMOS transistor Q1 and a source terminal S2 of the second PMOS transistor Q2. More specifically, two ends of the first resistor R1 are respectively connected to the source terminal S1 of the first PMOS transistor Q1 and to the fifth constant current source I5, and two ends of the second resistor R2 are respectively connected to the source terminal S2 of the second PMOS transistor Q2 and to the fifth constant current source I5. Both the first resistor R1 and the second resistor R2 have substantially the same resistance value “R”. Each of the first to the forth constant current sources I1˜I4 produces a constant current having substantially the same current value I as the current produced by the fifth constant current source I5. The first constant current source I1 is coupled to the source terminal S1 of the first PMOS transistor Q1 via the first switch SW1 to thereby selectively supply a constant current to the source terminal S1 of the first PMOS transistor Q1 through the operation of the first switch SW1. The second constant current source I2 is coupled to the source terminal S1 of the first PMOS transistor Q1 via the second switch SW2 to thereby derive a constant current out from the source terminal S1 of the first PMOS transistor Q1 through the operation of the second switch SW2. Similarly, the third constant current source I3 is coupled to the source terminal. S2 of the second PMOS transistor Q2 via the third switch SW3 to thereby supply a constant current to the source terminal S2 of the second PMOS transistor Q2 through the operation of the third switch SW3. The forth constant current source I4 is coupled to the source terminal S2 of the second PMOS transistor Q2 via the forth switch SW4 to thereby derive a constant current out from the source terminal S2 of the second PMOS transistor Q2 through the operation of the forth switch SW4. In addition, the hysteresis circuit for a comparator according to the present invention further comprises a switch element control means (not shown) for controlling the ON/OFF operations of the first to the forth switches SW1˜SW4. The switch element control means controls the first to the forth switches SW1˜SW4 based on the output signal Vout from the output terminal (not shown) of the comparator. If the output signal Vout from the output terminal of the comparator is in a logic low state, the first and the forth switches are turned ON, while the second and the third switches are turned OFF. Consequently, the first constant current source I1 supplies a constant current to the source terminal S1 of the first PMOS transistor Q1, and the forth constant current source I4 derives a constant current out from the source terminal S2 of the second PMOS transistor. If the output signal Vout from the output terminal of the comparator is in a logic high state, the first and the forth switches are turned OFF, while the second and the third switches are turned ON. Consequently, the third constant current source I3 supplies a constant current to the source terminal S2 of the second PMOS transistor Q2, and the second constant current source I2 derives a constant current out from the source terminal S1 of the first PMOS transistor Q1. The comparator employing the hysteresis circuit according to the present invention has a hysteresis characteristic as shown in FIG. 3. Specifically, when the output signal Vout from the output terminal of the comparator is in a logic low state, the output signal Vout will change from logic low to logic high only if the first input signal Vin+ is higher than the second input signal Vin− plus a voltage difference of “I×2R”. When the output signal Vout from the output terminal of the comparator is in a logic high state, the output signal Vout will change from logic high to logic low only if the first input signal Vin+ . is lower than the second input signal Vin− minus a voltage difference of “I×2R”. Depending on practical demands of the circuit design, the resistance value “R” and the current value “I” may be properly selected to obtain a desired fixed/adjustable hysteresis width, which is insensible to variations of the power supply voltage and the temperature. Next, the operation of the circuit according to the present invention will be described with reference to FIGS. 5(a), 5(b), 6(a) and 6(b). FIGS. 5(a) and 5(b) are circuit diagrams explaining the operations of the comparator as the output signal changes from logic low to logic high. When the output signal Vout from the output terminal of the comparator is in a logic low state, the first and the forth switches are ON and the second and the third switches are OFF, and therefore the first constant current source I1 supplies a constant current I to the source terminal S1 of the first PMOS transistor Q1 while the forth constant current source I4 derives a constant current I out from the source terminal S2 of the second PMOS transistor Q2. At this time, if the first input signal Vin+ at the input terminal of the comparator gradually increases so that the first input signal Vin+ exceeds the second input signal Vin−, the second PMOS transistor Q2 will be turned on but the first PMOS transistor Q1 has not yet been turned off. Therefore, as shown in FIG. 5 (a), each the first PMOS transistor Q1 and the second PMOS transistor Q2 conducts a current of “I/2”, and thus the current flowing through the first resistor R1 and the current flowing through the second resistor R2 are “I/2” and “3I/2”, respectively. Accordingly, a voltage difference between the source terminal S1 of the first PMOS transistor Q1 and the source terminal S2 of the second PMOS transistor Q2 is (I/2)×R+(3I/2)×R=I×2R. For this reason, when the first input signal Vin+ exceeds the second input signal Vin−, the output signal Vout will not immediately change from logic low to logic high. Instead, the output signal Vout changes from logic low to logic high only when the voltage difference ΔV between the first input signal Vin+ and the second input signal Vin− is greater than I×2R. As shown in FIG. 5 (b), after the output signal Vout changes from logic low to logic high, the first and the forth switches are OFF and the second and the third switches are ON. In this case, the first and the forth constant current sources I1 and I4 are considered no longer present, and therefore the third constant current source I3 supplies a constant current I to the source terminal S2 of the second PMOS transistor Q2 while the second constant current source I2 derives a constant current I out from the source terminal S1 of the first PMOS transistor Q1. At this time, the first PMOS transistor Q1 is turned OFF, and the second PMOS transistor Q2 conducts a current of “I”. Similarly, FIGS. 6(a) and 6(b) are circuit diagrams explaining the operations of the comparator as the output signal changes from logic high to logic low. When the output signal Vout from the output terminal of the comparator is in a logic high state, the first and the forth switches are OFF and the second and the third switches are ON, and therefore the third constant current source I3 supplies a constant current I to the source terminal S2 of the second PMOS transistor Q2 while the second constant current source I2 derives a constant current I out from the source terminal S1 of the first PMOS transistor Q1. At this time, if the first input signal Vin+ at the input terminal of the comparator gradually decreases so that the first input signal Vin+ falls below the second input signal Vin−, the first PMOS transistor Q1 will be turned ON but the second PMOS transistor Q2 has not yet been turned OFF. Therefore, as shown in FIG. 6 (a), each of the first PMOS transistor Q1 and the second PMOS transistor Q2 conducts a current of “I/2”, and thus the current flowing through the second resistor R2 and the current flowing through the first resistor R1 are “I/2” and “3I/2”, respectively. Accordingly, the voltage difference between the source terminal S1 of the first PMOS transistor Q1 and the source terminal S2 of the second PMOS transistor Q2 is −(I/2)×R−(3I/2)×R=−I×2R. For this reason, as the first input signal Vin+ falls below the second input signal Vin−, the output signal Vout will not immediately change from logic high to logic low. Instead, the output signal Vout changes from logic high to logic low only when the voltage difference ΔV between the first input signal Vin+ and the second input signal Vin− is smaller than −I×2R. As shown in FIG. 6(b), after the output signal Vout changes from logic high to logic low, the first and the forth switches are ON and the second and the third switches and OFF. In this case, the second and the third constant current sources I2 and I3 are considered no longer present, and therefore the first constant current source I1 supplies a constant current I to the source terminal S1 of the first PMOS transistor Q1 while the forth constant current source I4 derives a constant current I out from the source terminal S2 of the second PMOS transistor Q2. At this time, the second PMOS transistor Q2 is turned OFF, and the first PMOS transistor Q1 conducts a current of “I”. Although in the above embodiment of the present invention the first to the forth constant current sources I1˜I4 are designed to produce the same constant current I as the fifth constant current source I5 and the first resistor R1 and the second resistor R2 are designed to have the same resistance value R, it should be considered as illustrative and not restrictive. In other embodiments, constant current sources producing different current values and resistors having different resistance values may be employed, as long as the current values and resistance values are properly selected to obtain the hysteresis effect as described in the above embodiment. The hysteresis circuit according to the present invention is not only suitable for differential comparison but also for single-ended comparison. For differential comparison, two input terminals Vin+ and Vin− of the comparator are respectively connected to the two signals tobe compared. For single-ended comparison, the inverting input terminal Vin− of the comparator is connected to a constant DC reference voltage, and the non-inverting input terminal Vin+ of the comparator is connected to the signal to be compared. In the comparing device described with reference to FIG. 2, the input at the inverting input terminal of the comparator 26 is limited by the threshold voltage generator 22, and therefore the device is not suitable for differential input comparison. In contrast to the prior art, the hysteresis circuit according to the present invention is applicable in a broad range of circuits. While the present invention has been described with reference to the preferred embodiments thereof, it is to be understood that the invention should not be considered as limited thereby. Various modifications and changes could be conceived of by those skilled in the art without departuring from the scope of the present invention, which is indicated by the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to an electronic circuit, and particularly, to a circuit for providing hysteresis in a differential input comparator. 2. Description of the Related Art A typical comparator is provided with two input terminals for comparing an input voltage signal and a reference voltage signal respectively received at the two input terminals, amplifying the voltage difference between the two signals and then producing an output signal with a logic high voltage or a logic low voltage based on the voltage difference. Generally, a logic high signal is produced at the output of the comparator when the input voltage is higher than the reference voltage. On the other hand, a logic low signal is produced at the output of the comparator when the input voltage is lower than the reference voltage. In order to prevent erroneous changes in the output voltage of the comparator resulting from noises in the input voltage signal or in the reference voltage signal, a typical solution to provide a hysteresis circuit in the comparator, so that a threshold voltage at which the output voltage of the comparator changes from logic low to logic high is different from a threshold voltage at which the output voltage of the comparator changes from logic high to logic low. FIG. 1 is a graph showing the relation between the input voltage signal and the output voltage signal of a comparator with a hysteresis characteristic, in which the horizontal axis represents the input voltage signal Vin while the vertical axis represents the output voltage signal Vout. When the output voltage signal Vout is in a logic low state, the input voltage signal Vin must rise above an upper threshold voltage Vth so that the output voltage signal Vout will change from logic low to logic high. When the output voltage signal Vout is in a logic high state, the input voltage signal Vin must fall below a lower threshold voltage Vtl so that the output voltage signal Vout will change from logic high to logic low. The voltage difference between the upper threshold voltage Vth and the lower threshold voltage Vtl is referred to as a hysteresis width, which is usually designed to be several hundreds of Millivolts. R.O.C. Patent Publication No. 508567, titled “Hysteresis comparing device with constant hysteresis width” discloses a comparator circuit having a hysteresis characteristic. FIG. 2 illustrates a schematic circuit diagram of the hysteresis comparing device disclosed in the above patent. As shown in FIG. 2 , the hysteresis comparing device 20 comprises a threshold voltage generator 22 , a selection switching device 24 and a comparator 26 . The hysteresis comparing device 20 receives an input voltage signal Vin and produces an output voltage signal Vout. The threshold voltage generator 22 generates an upper threshold voltage Vth and a lower threshold voltage Vtl from a DC voltage signal Vdc according to a desired hysteresis width. The selection switching device 24 includes a first switch 24 a and a second switch 24 b , which are controlled on the basis of the output voltage signal Voutof the comparator 26 to select one of the upper threshold voltage Vth and the lower threshold voltage Vtl as a reference voltage signal of the comparator. When the output voltage signal Vout is in a logic low state, the switch 24 a is turned ON while the switch 24 b is turned OFF, and thus the upper threshold voltage Vth is output from the selection switching device 24 . On the other hand, when the output voltage signal Vout is in a logic high state, the switch 24 a is turned OFF while the switch 24 b is turned ON, and thus the lower threshold voltage Vtl is output from the selection switching device 24 . According to the above design, when the output voltage signal Vout is in a logic low state, the input voltage signal Vin must rise above the upper threshold voltage Vth so that the output voltage signal Vout will change from logic low to logic high; when the output voltage signal Vout is in a logic high state, the input voltage signal Vin must fall below the lower threshold voltage Vtl so that the output voltage signal Vout will change from logic high to logic low. Thereby, the hysteresis effect is achieved. However, the prior art circuit in FIG. 2 is designed by providing an external threshold voltage generating circuit to a comparator to thereby obtain a hysteresis effect, which is disadvantageous because of its slow switching rate and the complicated circuit components. Such a comparing device is impossible to be designed into an integrated circuit. Therefore, it is desired to develop comparator hysteresis circuit, which is fast in switching rate, simple in circuit structure and suitable for application in an integrated circuit. | <SOH> SUMMARY OF THE INVENTION <EOH>The object of the present invention is to provide a hysteresis circuit for a comparator, which is disposed in the comparator circuit and has the advantages of fast switching rate, simple structure and fewer components. Another object of the present invention is to provide a hysteresis circuit for a comparator, which is configured only by current source elements and resistor elements and thus is suitable for use in an integrated circuit to provide a hysteresis width insensible to variations of the power supply voltage and the temperature. The hysteresis circuit according to the present invention may be employed in a differential comparator having a differential input stage including a first transistor and a second transistor. Each of the first transistor and the second transistor has a gate terminal serving as one of two input terminals of the comparator. The comparator further includes a constant current source for supplying a constant current to the differential input stage of the comparator. The hysteresis circuit of the present invention comprises a first and a second resistor elements, a first to a forth constant current source elements anda first to a forth switch elements, all disposed in the above comparator. Both the first and the second resistor elements have the same resistance value. The first resistor element is coupled between a source terminal of the first transistor and the constant current source element of the comparator, while the second resistor element is coupled between a source terminal of the second transistor and the constant current source element of the comparator. Each of the first to the forth constant current source elements produces a constant current, which is of the same value as the current produced by the constant current source of the comparator. The first switch element is coupled between the first constant current source element and the source terminal of the first transistor so that the first constant current source element selectively supplies a constant current to the source terminal of the first transistor. The second switch element is coupled between the second constant current source element and the source terminal of the first transistor so that the second constant current source element selectively derives a constant current out from the source terminal of the first transistor. Symmetrically, the third switch element is coupled between the third constant current source element and the source terminal of the second transistor so that the third constant current source element selectively supplies a constant current to the source terminal of the second transistor. Similarly, the forth switch element is coupled between the forth constant current source element and the source terminal of the second transistor so that the forth constant current source element selectively derives a constant current out from the source terminal of the second transistor. ON/OFF operations of the first to the forth switch elements are controlled based on a signal from the output terminal of the comparator. If the signal from the output terminal of the comparator is a first logic value, then the first and the forth switch elements are turned ON while the second and the third switch elements are turned OFF. If the signal from the output terminal of the comparator is a second logic value, then the first and the forth switch elements are turned OFF while the second and the third switch element are turned ON. With the above configuration according to the present invention, a single-side hysteresis width equal to the current value I of the constant current source element multiplied by twice the resistance value R of the resistor element, i.e., a double-side hysteresis width equal to twice the single-side hysteresis width, can be provided. | 20040412 | 20050906 | 20050303 | 59267.0 | 0 | NGUYEN, LONG T | HYSTERESIS CIRCUIT USED IN COMPARATOR | SMALL | 0 | ACCEPTED | 2,004 |
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10,821,925 | ACCEPTED | Biodegradable common bile duct stent and the method for preparaing thereof | A biodegradable common bile duct stent and the method for preparing thereof are provided. The stent is made of biodegradable polymeric material with incorporation of X-ray opaque components. The stent adapt to anatomic shape of CBD or it can be sutured together with the wall of the bile duct. After placing in the duct, it maintains its position and does not slip. The circular tube of the stent being suitably sized and having multiple ring-shaped protruding rims at the outer wall and/or with larynx structure, leakage and outflow of the bile are thereby prevented. The process for manufacturing the stent comprises the following steps: (1) mixing and pelletizing of biodegradable polymer, X-ray opaque components and processing additives; (2) injection molding or extrusion-blowing followed by polishing of the exterior surface. In surgical operation on bile duct, the stent can replace the T-tube which is conventionally used to support the duct and guide bile drainage. It can reduce the time required for surgical operation and treatment, reduce possible complications and can be degraded and eliminated as the incision heals and the CBD regains its normal functions. | 1. A biodegradable common bile duct stent, wherein the said stent is made of biodegradable polymeric material with incorporation of X-ray opaque components; the wall of the stent is thin and the outer diameters of various parts of the stent are 1-3 times of the inner diameters of the corresponding parts of the common bile duct of a healthy person; and the said stent is fabricated according to the anatomic shape of common bile duct, and thus is suitable for longitudinal or transverse incisions at various parts of common bile duct and common hepatic duct. 2. The stent according to claim 1, wherein the stent has a shape selected from the group consisting of straight tube, Y-shape tube, fork-shape tube, vest-shape tube, and short tube. 3. The stent according to claim 1, wherein the stent has a length in the range of 10-80 mm and thickness of the wall in the range of 0.2-2 mm. 4. The stent according to claim 1, wherein the said biodegradable polymers are selected from the group consisting of poly(lactic acid), poly(glycollic acid), poly(ε-caprolactone) and random or block copolymer of lactic acid, glycollic acid and ε-caprolactone. 5. The stent according to claim 1, wherein the said X-ray opaque components comprise barium sulfate and inorganic salts or oxides of bismuth, tantalum or tungsten, and the amount of the X-ray opaque components is between 5 and 50% by weight based on the weight of the stent. 6. The stent according to claim 5, wherein the amount of X-ray opaque components is between 20 and 25% by weight based on the weight of the stent. 7. The stent according to claim 1, wherein the said wall has an outer surface comprising multiple protruding rims separated by a distance of between 5 and 10 mm, the cross section of ring is in a form of square with round angles, and the width and height of the ring are 1-2 mm respectively. 8. The stent according to claim 1, wherein the wall structure of the stent is fabricated into the shape similar to that of larynx duct, the length of larynx segmentum is 5-20 mm, the variation range of outer diameter is 2-10 mm, and the width ratio of the concave part and the convex part is 1-10. 9. The stent according to claim 1, wherein the length of larynx segmentum is 8-10 mm, the outer diameter is in a range of 4-6 mm, the width ratio of the concave part and the convex part is 3-5. 10. The stent according to claim 1, wherein the outer wall of left and right arm or of the upper entrance have ring-shaped protruding rims and the long arm is fabricated into larynx structure. 11. A method for the preparation of biodegradable common bile duct stent according to claim 1, comprising (1) mixing and pelletizing of biodegradable polymer, X-ray opaque components and processing additives; (2) injection molding or extrusion-blowing followed by polishing of the exterior surface. | FIELD OF THE INVENTION The present invention relates to a biodegradable polymeric common bile duct (CBD) stent and its method of preparation. BACKGROUND OF THE TECHNOLOGY The common bile duct exploration (CBDE) is a common surgical operation for treating gall-stone, bile duct narrowing and related complaints. In CBDE, a longitudinal incision is made in the common bile duct (CBD) and sutured after the operation. Since simple suturing often induces bile leakage or bile duct narrowing, and thus causes further complications, in clinical practice a T-tube is usually inserted to provide a support during the operation and to keep the bile duct open afterwards. Bile or other secretions can either flow into the intestine through the bile duct or flow out through the long arm of the T-tube fixed in an opening in body wall, thus avoiding complications due to bile duct narrowing or cholestasis. The combination of fitness between the T-tube and the bile duct wall, and the effective suturing will generally prevent the leakage of bile through the incision. The T-tube is removed 2 weeks after the operation, after the sinus formation around the tube. The insertion of the T-tube may sometimes lead to complications: (1) it may cause an inflamatory reaction, leading to swelling and narrowing of the bile duct; (2) It can induce bile duct infection caused by the counterflow action through its long arm or the infection around the drainage exit at the abdominal wall; (3) if the outflow of bile from the long arm of the T-tube approaches 300-800 ml/day, water-electrolyte disorders and acid-base imbalances occur. This may interfere with the normal mobility of intestine and inhibit the recovery of digestive functions; and (4) if the T-tube is left in position for an extended period it may cause pressure on the surrounding tissues and organs, possibly leading to perforation and adhesion. Furthermore the sinus may not form properly or even break when the T-tube is removed and bile leakage may occur. Alternatives to the T-tube include alternative stent designs such as “C tubes” and the like. All these methods necessitate leaving a stent embedded in the patient's body for about 2 weeks before it is manually removed. In some procedures the stent is inserted through the duodenum, and is moved out from the bile duct into and through the intestine taking advantage of the peristalsis and contraction of the bile duct sphincter. In such procedures it is very difficult to control the time and speed of transfer of the stent to the intestines and the procedure is thus difficult to be adopted clinically. Liver transplantation is performed to save the patients suffering from serious liver diseases. The operation involves cutting the CBD and suturing the CBD of the donor liver to that of the recipient. The success of liver transplantation depends heavily on the successful joining of the both CBDs. Because of the orientation of cutting and suturing, there is a high risk of bile leakage and bile duct narrowing. Generally a T-tube is required with its associated risks of complications. The CBD and pancreas duct have a common exit in the duodenum, so some patients need to perform a pancreatic operation to reconstruct the CBD, thus inevitably need to avoid the risk of bile leakage and bile duct narrowing. SUMMARY OF THE INVENTION The present invention provides a biodegradable CBD stent, which is made of biodegradable polymeric material with incorporation of X-ray opaque components; the wall of the stent is thin in thickness and the diameters of the stent (6-24 mm) are 1-3 times the diameters of CBD in a healthy person (0.6-0.8 cm); and the said stent is fabricated according to the anatomic shape of CBD, and thus is suitable for longitudinal or transverse incisions at each parts of CBD and common hepatic duct. The biodegradable stent of the present invention has following fundamental functions: (1) The stent provides a bolstering for CBD so that it can be conveniently sutured in operation. After the operation it can prevent the occurrence of duct narrowing. The stent also has the function of expanding the bile duct for patients suffering from bile duct narrowing. (2) The stent can block the incision of CBD and thus avoid the leakage of bile. (3) The stent can ensure free draining of bile into intestine completely without stasis or running off. Therefore it will not inflict harmful influence on liver functions and will eventually benefit motion of intestines and recovery of digestion functions. (4) Since the stent does not have drainage side tube, bile duct countercurrent infection and harmful effect on the surrounding tissues caused by the presence of T-tube can be avoided. (5) After the recovery of the bile duct functions, the stent undergoes biodegradation and the degraded products or fragments will flow into the intestine with the bile. It need not be taken out by surgical operation. This will alleviate the suffering of the patients, shorten the hospitalization time and lower the hospitalization expenses. (6) It can eliminate the inconvenience of body movement and the psychological dread of the patient due to the presence of T-tube in bile duct and can benefit the recovery of patients both physically and emotionally. The present invention also provides a method for the preparation of biodegradable CBD stent, comprising: (1) mixing and pelletizing of biodegradable polymer, X-ray opaque components and processing additives; (2) injection molding or extrusion-blowing followed by polishing of the exterior surface. The present invention will now be more fully described with reference to Figures which are presented by way of illustration and not limitation. A range of variants such as substitution of other materials or manufacturing methods will be readily apparent to those skilled in the art in light of the following embodiments and the figures and all such variants are considered to fall within the scope of the invention claimed. DESCRIPTION OF THE FIGURES FIG. 1: In vitro degradation curves for three types of copolymers of lactic acid and glycollic acid in bile. FIG. 2: Schematic diagram of the structure of the CBD stent, wherein the Reference Sign 20 is a straight-tube-shaped stent, Reference Sign 21 is a Y-shaped stent, Reference Sign 22 is a short-fork-shaped stent, Reference Sign 23 is a vest-shaped stent, and Reference Sign 24 is a short-tube-shaped stent. FIG. 3: Schematic diagram of the wall of the CBD stent, wherein Reference Sign 31 is the ring-shaped protruding rim at outer wall; Reference Sign 32 is the larynx structure. FIG. 4: Post-operation changes in ALP level in rat blood after CBDE and implantation of the CBD stent. DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION The biodegradable CBD stent of the present invention is made of biodegradable polymeric materials. Biodegradable polymers are functional materials developed in the later stage of the 20th century. Their medical uses become wider and wider nowadays, such as suture thread, internal-fixation of bone fracture and the like. The materials have the following characteristics and advantages: After the surgical operation, the stent material undergoes biodegradation and can be absorbed and metabolized by human body and thus there is no need to take the stent out by a second surgical operation. It has been demonstrated by tests that the degradation rate of the lactic acid based polymers is very fast. FIG. 1 illustrates the weight loss curves of three different polymers during the in vitro degradation in bile. Within 24 days, the weight losses approach 70-100%. In vivo tests show that in about 5 weeks, PLGA (a kind of copolymer formed from lactic acid and glycollic acid) small tube imbedded in CBD of rat can be degraded into fragments and flows into intestine along with the bile. Therefore the use of such kind of material can completely overcome the main disadvantages of T-tube. Since the said stent degrades naturally in body and is not necessary to be taken out by surgical operation or other method, it is called “degradable CBD stent”. In the present invention, the biodegradable polymers used for preparing the CBD stent are selected from the group consisting of poly(lactic acid), poly(glycollic acid), poly(ε-caprolactone) and random or block copolymers of lactic acid, glycollic acid and ε-caprolactone. The steric configuration of poly(lactic acid) could be either laevorotary, dextrorotary or racemic. In the selection of the materials, it is necessary to take account of the velocity of biodegradation, processing properties, post-processing properties, and surface feeling of the product and the like. Since polymers of lactic acid possess excellent processing property, the shape design of the CBD stent of the present invention could meet the requirements of surgical operation of CBD very well. For example, the stent has a shape selected from the group consisting of straight tube, Y-shape tube, fork-shape tube, vest-shape tube, and short-tube shape. The said stent adopts a shape of thin-walled circular tube with outer diameter of 6-25 mm, thickness of the wall in the range of 0.2-2 mm, and length in the range of 10-80 mm. It imitates the anatomic shape of the CBD in appearance. FIG. 2 is a schematic profile of the stent structure wherein Reference Sign 20 is a straight-tube-shaped stent that has the simplest structure, lowest cost and is suitable for incision at the middle or lower part of the CBD; 21 is a Y-shaped stent suitable to be used for a longitudinal or transverse incision at common hepatic duct; 22 is a short-fork-shaped stent; 23 is a vest-shaped stent suitable for longitudinal or transverse incision at CBD; 24 is a short-tube-shaped stent suitable for a transverse incision at common bile(hepatic) duct. The fringe of the stent should be as smooth as possible in order to reduce possible injury to the wall of the bile duct during the operation. One of the technical difficulties in using internal-imbedded stent is how to prevent the slip of the stent after operation that would result in blockade of the duct and exposure of the sutured incision. The inner-imbedded stent of the present invention adopts the anatomic shape of the CBD wherein Y-shaped stent 21 has left, right and long arms corresponding to the left, right hepatic ramus duct and CBD respectively. Once implanted, it can stay at the specific place and will not slip. Short-fork-shaped stent 22 and vest-shaped stent 23 have very short left, right arms or have no left, right arms. They can conveniently be imbedded without long incision. Their upper end entrance is relatively wider to facilitate the entering of the bile. The joining part of the three arms is flattened to ensure precise locating in the CBD after the embedment. Short-tube-shaped stent 24 is wider at the two ends and narrower in the middle. Since temporary wall thickening would generally occur at the sutured part of the incision after the operation, the stent will get stuck by such design and would not slip. Straight-tube-shaped stent 20 can not be naturally fixed at a specific position. However since the material used to make the stent is flexible and soft, the stent can be sutured on the wall of the bile duct to fix its position. Of course, stents of other shapes can also be sutured with the wall of the bile duct. Another technical difficulty in using inner-imbedded stent is how to prevent the leaking of bile from the interstices between the stent and the inner wall of bile duct and then flowing out of the sutured incision. The said stent of the present invention adopts an anatomic shape of the CBD and the outer diameter of the stent is 1-3 times of the CBD of a healthy person. This is due to the fact that patient that needs a surgical operation of CBD often has the symptom of dilatation of CBD and his or her CBD is usually 1-3 times that of a healthy person. This large outer diameter of the stent, especially even larger outer diameter at the upper end, makes the stent tightly adhere to the inner wall of the bile duct without any interstices and therefore leakage of bile can be prevented. As illustrated by 31 in FIG. 2 and FIG. 3, the wall has an outer surface comprising multiple protruding rims separated by a distance of between 5 and 10 mm, the cross section of ring is in a form of square with round angles, and the width and height of the ring are 1-2 mm, respectively. Their height and shape will not harm the inner wall of the bile duct, but effectively decrease the interstices between the stent and inner wall of the CBD and thus prevent any leakage of bile. The structure, except the protruding part, will exert relatively low tension on the wall of bile duct and will be beneficial to the recovery of functions. Rings themselves have reinforcing effect on the stent and therefore the thickness of the stent wall can suitably be reduced. As a result, the amount of raw material consumed can be lowered and the time required for degradation and excretion can be shortened. As illustrated by 32 in FIG. 3, the wall structure of the stent is fabricated into the shape similar to that of larynx duct. The length of larynx segmentum is 5-20 mm, preferably 8-10 mm; the variation range of outer diameter is 2-10 mm, preferably 4-6 mm; and the width ratio of the concave part and the convex part is 1-10, preferably 3-5. This design will have the same effect of preventing leakage of bile as the multiple ring-shaped protruding rims do. In addition, the design possesses advantages of homogeneity in thickness of stent wall, easiness of deformation, tight contact with the duct wall and low stress. Obviously, excellent performances can be obtained if the above-mentioned two structures are utilized together. For example, ring-form protruding rim is formed on the left and right arms of the stent and the outer wall of upper entrance while larynx duct structure is adopted for the long arm part. In order to conveniently monitor the position, shape and degradation status of the stent after the operation, opaque pigment under X-ray, such as BaSO4 or inorganic salts and oxides of bismuth, tantalum and tungsten is incorporated into the stent. The amount of X-ray opaque components is between 5 and 50% by weight, preferably between 20 and 25% of weight based on the weight of the stent. Although addition of X-ray opaque components would cause some changes in the mechanical properties of the polymer, it does not hamper the successful use of the stent. During the degradation of the stent, these compounds may dissociate and flow into the intestine along with the bile and be excreted out of human body. The manufacturing process for the CBD stent comprises mixing of the raw materials followed by pelletization and molding. Conventional mixer or high-speed mixer is employed in mixing of the raw materials, and screw extruder is employed for pelletization. Injection molding or extrusion-blowing can be used for the fabrication of the stent. If necessary, second molding or post-processing may be used. Those skilled in the art can select suitable process based on those known in prior art. The above raw materials, structures and method of preparations of the CBD stent will be further described by the following specific examples. However, the present invention is not limited by these examples. Based on the principles and spirit of the present invention, those skilled in the art can make appropriate improvements or developments on the types of raw materials, structure design and processing techniques. EXAMPLES The results of animal experiments are given as follows. The stent of the present embodiment was made of PLGA copolymer of L-lactide (LA) and glycolide (GA) with a molecular weight of about 120,000 and an LA/GA ratio of 70/30, which was synthesized by the Changchun Institute of Applied Chemistry. The polymer was extruded with a Model XSS-300 extruder (φ 20 mm, L/D=25) to give thin tubes with an outer diameter of 1.0 mm and an inner diameter of 0.6 mm. The thin tube was cut into stents about 5.5 mm in length and two ends were slightly modified so as to make the ends slightly smaller and smoother in cross-section. The stents made in this way were then sterilized and packed ready for use. 110 Wistar rats are selected and divided into a control group and a test group. Explorations were carried out on the CBDs of the both groups, longitudinal incisions approximately 2 mm long were sutured with 11-0 nylon thread with a 0.4-0.5 mm interval. For control group, the incision was directly sutured after the operation, while for the test group, a stent sterilized with 5% iodine was implanted through the incision after the exploration. The position of the stent was properly adjusted to locate the incision in the middle of the stent and then the incision was sutured. During the operation, operation time and suturing time were recorded. On the third day after operation, some animals were dissected to observe whether leakage of bile was present. 5 rats were sacrificed to examine the appearance, inner diameter and degradation state of the stents at one week interval. Alkaline phosphatase (ALP) was measured from the blood samples of the rats. 9 weeks after the operation, body weight, outer diameter at the near end of the CBD, ALP and tissue pathology of liver were compared between both groups of rats. Results: There was no significant difference in the suturing time, total time of operation or percentage of occurrence of cholorrhagia after 3 days between the two groups. After 2 weeks the inner diameter of the stent was slightly expanded; After 3 weeks the stent became deformed but still allowed free drainage; after 4 weeks the stent began to fragmentize and after 5 weeks fragments were excreted out of CBD. The indexes of ALP value, outer diameter of the near end of the CBD, body weight and injury to the liver for the test group was better than for the control group, which indicates that the degree of bile duct narrowing after the operation was significantly improved by using the CBD stent. Variation of ALP values during the 9 weeks after operation is illustrated in FIG. 4. The ALP index reflects the change in liver function. The value of ALP increases when there is bile duct narrowing and cholestasis. FIG. 4 shows that simple suturing of the CBD resulted in continuous and permanent elevation of ALP level. When the stent was implanted, the observed elevation of ALP level was only temporary and the ALP value would gradually decline, returning to its normal level after 4 weeks. It should be pointed out that the diameter of CBD of rat is about 1 mm and its thickness is about 0.1 mm, much slender and thinner than those of the human beings. Therefore, the exploration, implantation and suturing of CBD for rat were performed under operating microscope and were much more difficult than the same operation for human body. The successful test for the rats indicates that the present invention is clinically applicable based on the materials, stent structure and manufacturing process used in the test as well as considering the dimension and shape of human CBD. | <SOH> BACKGROUND OF THE TECHNOLOGY <EOH>The common bile duct exploration (CBDE) is a common surgical operation for treating gall-stone, bile duct narrowing and related complaints. In CBDE, a longitudinal incision is made in the common bile duct (CBD) and sutured after the operation. Since simple suturing often induces bile leakage or bile duct narrowing, and thus causes further complications, in clinical practice a T-tube is usually inserted to provide a support during the operation and to keep the bile duct open afterwards. Bile or other secretions can either flow into the intestine through the bile duct or flow out through the long arm of the T-tube fixed in an opening in body wall, thus avoiding complications due to bile duct narrowing or cholestasis. The combination of fitness between the T-tube and the bile duct wall, and the effective suturing will generally prevent the leakage of bile through the incision. The T-tube is removed 2 weeks after the operation, after the sinus formation around the tube. The insertion of the T-tube may sometimes lead to complications: (1) it may cause an inflamatory reaction, leading to swelling and narrowing of the bile duct; (2) It can induce bile duct infection caused by the counterflow action through its long arm or the infection around the drainage exit at the abdominal wall; (3) if the outflow of bile from the long arm of the T-tube approaches 300-800 ml/day, water-electrolyte disorders and acid-base imbalances occur. This may interfere with the normal mobility of intestine and inhibit the recovery of digestive functions; and (4) if the T-tube is left in position for an extended period it may cause pressure on the surrounding tissues and organs, possibly leading to perforation and adhesion. Furthermore the sinus may not form properly or even break when the T-tube is removed and bile leakage may occur. Alternatives to the T-tube include alternative stent designs such as “C tubes” and the like. All these methods necessitate leaving a stent embedded in the patient's body for about 2 weeks before it is manually removed. In some procedures the stent is inserted through the duodenum, and is moved out from the bile duct into and through the intestine taking advantage of the peristalsis and contraction of the bile duct sphincter. In such procedures it is very difficult to control the time and speed of transfer of the stent to the intestines and the procedure is thus difficult to be adopted clinically. Liver transplantation is performed to save the patients suffering from serious liver diseases. The operation involves cutting the CBD and suturing the CBD of the donor liver to that of the recipient. The success of liver transplantation depends heavily on the successful joining of the both CBDs. Because of the orientation of cutting and suturing, there is a high risk of bile leakage and bile duct narrowing. Generally a T-tube is required with its associated risks of complications. The CBD and pancreas duct have a common exit in the duodenum, so some patients need to perform a pancreatic operation to reconstruct the CBD, thus inevitably need to avoid the risk of bile leakage and bile duct narrowing. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides a biodegradable CBD stent, which is made of biodegradable polymeric material with incorporation of X-ray opaque components; the wall of the stent is thin in thickness and the diameters of the stent (6-24 mm) are 1-3 times the diameters of CBD in a healthy person (0.6-0.8 cm); and the said stent is fabricated according to the anatomic shape of CBD, and thus is suitable for longitudinal or transverse incisions at each parts of CBD and common hepatic duct. The biodegradable stent of the present invention has following fundamental functions: (1) The stent provides a bolstering for CBD so that it can be conveniently sutured in operation. After the operation it can prevent the occurrence of duct narrowing. The stent also has the function of expanding the bile duct for patients suffering from bile duct narrowing. (2) The stent can block the incision of CBD and thus avoid the leakage of bile. (3) The stent can ensure free draining of bile into intestine completely without stasis or running off. Therefore it will not inflict harmful influence on liver functions and will eventually benefit motion of intestines and recovery of digestion functions. (4) Since the stent does not have drainage side tube, bile duct countercurrent infection and harmful effect on the surrounding tissues caused by the presence of T-tube can be avoided. (5) After the recovery of the bile duct functions, the stent undergoes biodegradation and the degraded products or fragments will flow into the intestine with the bile. It need not be taken out by surgical operation. This will alleviate the suffering of the patients, shorten the hospitalization time and lower the hospitalization expenses. (6) It can eliminate the inconvenience of body movement and the psychological dread of the patient due to the presence of T-tube in bile duct and can benefit the recovery of patients both physically and emotionally. The present invention also provides a method for the preparation of biodegradable CBD stent, comprising: (1) mixing and pelletizing of biodegradable polymer, X-ray opaque components and processing additives; (2) injection molding or extrusion-blowing followed by polishing of the exterior surface. The present invention will now be more fully described with reference to Figures which are presented by way of illustration and not limitation. A range of variants such as substitution of other materials or manufacturing methods will be readily apparent to those skilled in the art in light of the following embodiments and the figures and all such variants are considered to fall within the scope of the invention claimed. | 20040412 | 20060822 | 20050113 | 58503.0 | 0 | GHERBI, SUZETTE JAIME J | BIODEGRADABLE COMMON BILE DUCT STENT AND THE METHOD FOR PREPARAING THEREOF | SMALL | 0 | ACCEPTED | 2,004 |
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10,821,998 | ACCEPTED | Vehicle suspension lift spacer | The vehicle suspension lift spacer of the present invention fits between the coil spring and the upper spring receiver of the front suspension. It is made by welding stock flat and cylinder stock material, making it cheap to make and sufficiently rugged for the desired use. The lift spacer is generally cylindrical, having a common axis with an axially mounted shock absorber. The lift spacer has a flat ring upper attachment plate having upward-spaced bolts for attachment through the upper coil spring receiver and shock tower mounts. A lift member is a cylindrical section welded coaxially to the underside of the upper attachment plate and determines the amount of lift of the lift spacer. A flat ring bearing is coaxially welded to the cylindrical lift member for bearing against the coil spring. A cylindrical guide member is welded to the lower side of the bearing plate. | 1. A generally cylindrical lift spacer for a vehicle coil suspension, comprising: an upper attachment plate configured as a flat ring defining a central axis and having an outer edge defining an outer diameter, an inner edge defining an inner diameter, an upper surface, a lower surface and a securing bolt peripheral portion; a cylindrical lift member depending axially from said upper attachment plate and having upper and lower edges, an inner surface defining an inner diameter, and an outer surface defining an outer diameter spaced inward from said outer edge of said upper attachment plate so as to define a securing bolt peripheral portion of said upper attachment plate; a bearing plate depending axially from said cylindrical lift member and configured as a flat ring having an outer edge defining an outer diameter, an inner edge defining an inner diameter, an upper surface, and a lower surface; a cylindrical guide member depending axially from said bearing plate and having upper and lower edges, an inner surface defining an inner diameter, and an outer surface defining an outer diameter; and a plurality of securing bolts having threaded shafts extending upward from said securing bolt peripheral portion of said upper attachment plate; said lift spacer having an inner diameter such as to axially receive an axially mounted shock absorber; said upper attachment plate outer diameter being such as to fit within a coil receiver of the vehicle coil suspension; said bearing plate having an outer diameter such that said vehicle spacer rests on the coil of the vehicle coil suspension; said cylindrical guide member having an outer diameter and a vertical length such as to axially fit within the coil spring of the vehicle coil spring and maintain said lift spacer in alignment with the coil spring. 2. The lift spacer of claim 1, wherein said plurality of securing bolts consists of three securing bolts. 3. The lift spacer of claim 2, said securing bolt peripheral portion of said upper attachment plate defining three equally spaced throughbores for receiving said securing bolts. 4. The lift spacer of claim 3, said securing bolts having heads and threaded shafts, said shafts being inserted upwardly through corresponding said throughbores. 5. The lift spacer of claim 4, said securing bolt heads being welded to said lower surface of upper attachment plate. 6. The lift spacer of claim 5, said securing bolts having securing nuts and washers, said shafts of said bolts being of sufficient length as to extend through the upper spring receiver and the shock tower mounts of the suspension and be secured by said securing nuts and washers. 7. The lift spacer of claim 1, wherein said upper edge of said lift member is welded to said lower surface of said upper attachment plate. 8. The lift spacer of claim 7, wherein said inner diameter of said lift member is greater than said inner diameter of said upper attachment plate and said lift member is welded to said upper attachment plate along the respective upper inner and outer surfaces of said lift member at said upper edge thereof. 9. The lift spacer of claim 8, wherein said inner diameter of said bearing plate is less than the inner diameter of said lift member and said lift member is welded to said upper surface of said bearing plate along the lower inner surface of said lift member at said lower edge thereof. 10. The lift spacer of claim 9, wherein said inner diameter of said guide member is less than the inner diameter of said lift member and said guide member is welded to said lower surface of said bearing plate along the upper inner surface of said guide member at said upper edge thereof. 11. The lift spacer of claim 1, wherein the amount of lift imparted to said suspension by said vehicle suspension lift spacer is selectable by selecting a desired length between said upper and lower edges for said lift member. 12. A generally cylindrical lift spacer for a vehicle coil suspension, comprising: an upper attachment plate configured as a flat ring defining a central axis and having an outer edge defining an outer diameter, an inner edge defining an inner diameter, an upper surface, a lower surface and a securing bolt peripheral portion; a cylindrical lift member depending axially from said upper attachment plate and having upper and lower edges, an inner surface defining an inner diameter, and an outer surface defining an outer diameter spaced inward from said outer edge of said upper attachment plate so as to define a securing bolt peripheral portion of said upper attachment plate; a bearing plate depending axially from said cylindrical lift member and configured as a flat ring having an outer edge defining an outer diameter, an inner edge defining an inner diameter, an upper surface, and a lower surface; a cylindrical guide member depending axially from said bearing plate and having upper and lower edges, an inner surface defining an inner diameter, and an outer surface defining and outer diameter; and three equally spaced securing bolts having threaded shafts extending upward from said securing bolt peripheral portion of said upper attachment plate; said securing bolt peripheral portion of said upper attachment plate defining three equally spaced throughbores for receiving said securing bolts; said securing bolts having heads and threaded shafts, said shafts being inserted upwardly through corresponding said throughbores; said lift spacer having an inner diameter such as to axially receive an axially mounted shock absorber; said upper attachment plate outer diameter being such as to fit within a coil receiver of the vehicle coil suspension; said bearing plate having an outer diameter such that said vehicle spacer rests on the coil of the vehicle coil suspension; said cylindrical guide member having an outer diameter and a vertical length such as to axially fit within the coil spring of the vehicle coil spring and maintain said lift spacer in alignment with the coil spring. 13. The lift spacer of claim 12, said securing bolt heads being welded to said lower surface of upper attachment plate. 14. The lift spacer of claim 5, said securing bolts having securing nuts and washers, said shafts of said bolts being of sufficient length as to extend through the upper spring receiver and the shock tower mounts of the suspension and be secured by said securing nuts and washers. 15. The lift spacer of claim 12, wherein the amount of lift imparted to said suspension by said vehicle suspension lift spacer is selectable by selecting a desired length for said lift member. 16. The lift spacer of claim 12, wherein each of said upper attachment plate and said bearing plate has a thickness of about ¼ inches, their respective diameters are about 6 ½ inches, and their inner diameters are about 3 to about 3 ½ inches. 17. The lift spacer of claim 16, wherein said guide member is about 1 ⅜ inches in length, having a wall about ⅛ inch in thickness and an inner diameter of at least 3 inches. 18. The lift spacer of claim 17, wherein said lift member has a wall about 3/16 inches in thickness. 19. A method of making a generally cylindrical lift spacer for a vehicle coil suspension, comprising the steps of: cutting a flat ring from flat metal stock to form an upper attachment plate; drilling three equally spaced throughbores proximate the perimeter of said attachment plate; cutting a flat ring from flat metal stock to form a bearing plate; cutting a cylindrical segment from cylindrical metal stock to form a lift member; cutting a cylindrical segment from cylindrical metal stock to form a guide member; axially aligning said lift member on said attachment plate and welding said lift member to said attachment plate; axially aligning said bearing plate on said lift member and welding said bearing plate to said lift member; axially aligning said guide member on said bearing plate and welding said guide member to said lift member; and inserting three securing bolts upward through respective said throughbores defined by said attachment plate and welding the heads of said securing bolts to said attachment plate. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to vehicle suspensions. More particularly, the present invention relates to suspension lift spacers for use with coil springs. 2. Description of the Related Art The use of vehicles for off-road travel is popular to reach remote camping, fishing, and hunting locations and has developed into a sport in itself. It is common to employ spacers to the suspension to lift the vehicle relative to the ground so as to increase its clearance. This allows the use of larger tires and to travel over rugged terrain. The use of standard pickup trucks and the like for off-road adventure driving is common, however, their suspensions are not originally designed for such use. The use of suspension lift spacers in the suspensions improves their utility for off-road use by increasing ground clearance for rough terrain. Such spacers must be designed for each particular truck make and model. The Dodge Ram 1500 truck, for example, has coil springs and thus requires a spacer fitting between the coil spring and the upper or lower spring receiver and must accommodate an axial shock absorber. Lift spacers are presently available, typically in 2″ and 3″ lift sizes, however known spacers require special casting and/or expensive machining. It would be desirable to provide such a suspension lift which is simple in design, made from readily available plate and cylinder stock, requires no expensive machining, and is sufficiently rugged for its intended use. U.S. Pat. No. 3,830,482, issued Aug. 20, 1974, to Norris describes an adjustable coil spring lifter to provide lift or restore loaded spring height. U.S. Pat. No. 6,149,171, issued Nov. 21, 2000, to Bono et al. describes a coil spring isolator for a vehicle suspension. U.S. Pat. No. 6,188,039, issued Feb. 13, 2001, to Gass, describes a projection welded panel spacer and the method for making the spacer by welding flats to tube stock. U.S. Pat. No. 6,481,071 B1, issued Nov. 19, 2002, to Newhan, describes a suspension kit to raise a vehicle front end. U.S. Pat. No. 6,543,828 B1, issued Apr. 8, 2003, to Gass, describes a welded panel spacer and method of making the spacer. U.S. Pat. No. 6,642,471 B2, issued Nov. 4, 2003, to Imai et al., describes a method for welding steels including plate to cylindrical stock. Internet Website http://Performancelifts.com describes a Daystar 02-24 Ram 1500 2″ lift spacer. Internet Website http://www.daystarweb.com describes front coil spring spacer kits for Dodge Ram 1500 suspensions. Internet Website http://rough.roughcountry.com of Rough Country a division of Heckethorn Products, Inc. is a source for a coil spring spacer for Dodge Ram 1500 suspensions (See FIG. 5 of the instant application). None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus a vehicle suspension lift spacer for Dodge Ram 1500 trucks solving the aforementioned problems is desired. SUMMARY OF THE INVENTION The vehicle suspension lift spacer of the present invention is designed to fit between the upper end of the coil spring and the upper spring receiver of the front suspension of a Dodge Ram 1500 truck. It is made by cutting and welding stock flat and cylinder stock material, making it cheap to make and sufficiently rugged for the desired use. No special casting or machining is required. The lift spacer is generally cylindrical, having a central axis in common with the axially mounted shock absorber extending downward therethrough. The lift spacer has an upper attachment plate in the shape of a flat ring having equally spaced bolts extending upward for attachment through the upper coil spring receiver and shock tower mounts. The lift member is a cylindrical section of appropriate length and is welded coaxially to the underside of the upper attachment plate. A bearing plate in the shape of a flat ring is coaxially welded to the lower edge of the cylindrical lift member for bearing against the upper end of the coil spring. A cylindrical guide member is welded to and coaxially depends from the lower side of the bearing plate to maintain the lift member properly placed relative to the outer coil spring and the inner shock absorber. The spacer may be provided in desired lengths, and typically 2″ and 3″ lengths. The desired length is obtained by selecting the length of the cylindrical section, the thickness of the upper attachment plate and bearing plate remaining a constant. The lift spacer may be made from steel or other appropriate material. It is an aspect of the invention which provides improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. These and other aspects of the present invention will become readily apparent upon further review of the following specification and drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an environmental, perspective view of a suspension lift spacer according to the present invention. FIG. 2 is a section view drawn along lines 2-2 of FIG. 1. FIG. 3 is a bottom view of the suspension lift spacer of FIG. 1. FIG. 4 is an exploded view of the suspension lift spacer of FIG. 1. FIG. 5 is a prior art suspension lift spacer. Similar reference characters denote corresponding features consistently throughout the attached drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is a coil spring suspension lift spacer for insertion between a coil spring and its upper receiver. The inventive lift spacer increases the clearance of the vehicle for off-road use. This lifts spacer is particularly useful in coil spring suspensions where the shock absorber extends axially through the coil spring. Referring to FIG. 1, there is shown an environmental, perspective view of the coil spring suspension lift spacer referred to by reference number 10. Lift spacer 10 is integral and generally cylindrical in shape, defining a central axis, and includes an upper attachment plate 12 configured as a flat ring, a cylindrical lift member 14 depending from the attachment plate 12 defining the height of lift of the lift spacer 10, a bearing plate 16 configured as a flat ring and depending from the cylindrical lift member 14, and a cylindrical guide member 18 depending from bearing plate 16. Upper attachment plate 12 has a peripheral portion having three threaded securing bolts equally spaced around its circumference proximate the outer edge thereof and extending upward therefrom. As shown in FIG. 1, coil spring S is vertically separated from coil receiver R by lift spacer 10, thus adding height to the suspension represented by vehicle suspension arms A. Generally, suspension arms A are permanently attached to coil receiver R by welding. A suspension tower T is in the general shape of a tripod and is generally bolted at its base to the upper side of coil receiver R proximate the periphery thereof. The suspension tower T provides an upper mount for shock absorber S. Shock absorber S extends axially downward through coil spring C and is mounted at the base thereof (not shown) in a known manner. With lift spacer 10 in place, upper attachment plate 12 bears against the lower surface of coil spring upper receiver R and bolts 20 act as studs and take the place of the original suspension bolts (not shown), extending upward through the existing bolt receiving bores of receiver R and the lower legs of shock tower T and are secured by washers 60 and nuts 62 (see FIG. 4). A ring-like rubber isolator (not shown) conforming to the underside of coil receiver R is supplied with the suspension to provide sound and vibration isolation from the coil spring C to the upper suspension. During installation of the inventive lift member, this rubber isolator may be placed between the top of the coil spring C and the bearing plate 16 (not shown) as desired to provide sound and vibration isolation from the lower suspension and spring to the inventive lift spacer 10. Lift member 14 is a section of cylindrical pipe or steel stock, the length of which may be selected to determine the amount of lift added to the vehicle suspension. Bearing plate 16 bears against the upper end of coil spring C, performing the function of coil receiver R in the original suspension configuration. Guide member 18 extends axially downward in the annular space between coil spring 18 and shock absorber S to maintain lift spacer 10 in alignment with coil spring C while allowing the shock absorber S to extend therethrough. Upper attachment plate 12 has a first outer diameter such as to fit within upper spring receiver R. Lift member 14 has a second outer diameter which is less than the first diameter defined by upper attachment plate 12 so as to provide clearance for installation of securing bolts B. Bearing plate 16 has an outer diameter equal to or larger than the first outer diameter defined by said upper attachment plate 12. Guide member 18 has a fourth diameter less than the diameter of bearing plate 16 and is of such an outer diameter as to fit axially within coil spring C. Guide member 18, as well as the other components of the lift spacer 10 has an inner diameter at least sufficient to receive an axial shock absorber therethrough. Referring to FIG. 2, there is shown a sectional view through lift member 14 of vehicle suspension lift member 10 looking upward. Attachment plate 12 is in the form of a flat ring having an upper surface with outer edge 22 and an inner edge 24. Lift member 12 is a cylindrical segment having an upper edge and a lower edge and an outer surface 34 defining an outer diameter and an inner surface 32 defining an inner diameter. Lift member 12 is spaced outward from inner edge 24 of attachment plate 12 and is secured to its lower surface 26 by welding as illustrated by weld beads W. Bolt heads 30 of bolts 20 are welded in place to the lower surface 26 of the peripheral portion as illustrated by weld beads W. Bolts 20 are equally spaced around a peripheral portion of upper attachment member 12 proximate its outer edge 22 and extend upward from heads 30 through corresponding throughbores (see FIG. 4) for securing lift spacer 10 to coil spring upper receiver R and shock tower T (see FIG. 1). Referring to FIG. 3, there is shown a bottom view of vehicle suspension lift spacer 10 showing bearing plate 16 and guide member 18. Bearing plate 16 has a flat ring configuration and is mounted coaxially and depending from lift member 14 by welding as illustrated by weld bead W. Bearing plate 16 has an upper surface having an outer edge 40, defining an outer diameter, and an inner edge 42, defining an inner diameter thereof. Guide member 18 is mounted coaxially with bearing plate 16 by welding to its lower surface 44, as illustrated by weld bead W, proximate and spaced outward from inner edge 42. Guide member 18 has an upper edge and a lower edge and has an outer surface 50 defining and outer diameter and an inner surface 52 defining an inner diameter. The outer diameter of guide member 18 as defined by outer surface 50 is preferably about equal to or less than the inner diameter of lift member 14 and is axially mounted relative thereto. Guide member 14 is preferably of sufficient length to maintain the spacing of coil spring C and shock absorber S. Referring to FIG. 5, there is shown an exploded view showing the upper attachment plate 12, lift member 14, bearing plate 16, and guide member 18 as axially aligned. Also shown are the securing bolts 20 as aligned with spaced throughbores in upper attachment plate 12 and having washers 60 and nuts 62. Although it is preferred that bolts 20 be welded to attachment plate 12 as shown in FIG. 2, they may be separately inserted when mounting lift spacer 10 in the vehicle suspension. FIG. 5 shows an environmental elevation view of a prior art vehicle suspension lift spacer for coil springs. In this design, the lift spacer is generally cylindrical and the lift member L is made of cast iron, machined to form an integral unit, the wall curving upward and outward to form a ring for mounting securing bolts B. A bearing plate BP is welded to lift member L along the internal wall (not shown). A guide member G is welded to bearing plate BP along the internal wall (not shown). This vehicle suspension lift spacer is available for Dodge Ram 1500 trucks from the Rough Country, a division of Heckethorn Products, Inc., 1400 Morgan Road, Dyersburg, Tenn., having the Internet address http://rough.roughcountry.com. The two flat rings for the upper attachment plate 12 and the bearing plate 16 of the lift spacer of the present invention are preferably laser cut from ¼″ mild steel stock with an outer diameter of about 6 ½″ and an inner diameter of from about 3″ to about 3 ½″ for passage of the shock absorber. The lift member and the guide member of the present invention are preferably cut from appropriate sized mild steel cylindrical stock, pipe, or tubing. The lift member 14 is cut from 3/16″ wall thickness tubing. The length of the lift member is selected for the amount of lift desired, a 2″ lift spacer requiring a 1 ½″ lift member and a 3″ lift spacer requiring a 2 ½″ lift member. The guide member 18 is cut from ⅛″ wall thickness tubing about 1 ⅜″ in length and has an inner diameter of at least 3″. The diameter of the lift member 18 is preferably greater than that of guide member 18 to impart maximum strength to the lift spacer assembly. Welding may be carried out with a conventional welder. Assembly and welding is preferably carried out in an inverted fashion by axially aligning the lift member 14 on the lower side of attachment plate 14 and welding along the upper edge of lift member 14 on both inner and outer sides; axially aligning bearing plate 16 on the lower edge of lift member 14 and welding along the lift member lower edge on its inner side; and axially aligning guide member 18 on the lower surface 44 of bearing plate 16 and welding along the upper edge of inner and outer walls 52 and 50, respectively. The securing bolts 20 may then be inserted in the throughbores in the peripheral portion of attachment plate 12 and the heads 30 welded to the lower surface 26 of attachment plate 12. Welding of the material can be performed inside the cylindrical tubing or pipe, outside, or a combination of both. It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to vehicle suspensions. More particularly, the present invention relates to suspension lift spacers for use with coil springs. 2. Description of the Related Art The use of vehicles for off-road travel is popular to reach remote camping, fishing, and hunting locations and has developed into a sport in itself. It is common to employ spacers to the suspension to lift the vehicle relative to the ground so as to increase its clearance. This allows the use of larger tires and to travel over rugged terrain. The use of standard pickup trucks and the like for off-road adventure driving is common, however, their suspensions are not originally designed for such use. The use of suspension lift spacers in the suspensions improves their utility for off-road use by increasing ground clearance for rough terrain. Such spacers must be designed for each particular truck make and model. The Dodge Ram 1500 truck, for example, has coil springs and thus requires a spacer fitting between the coil spring and the upper or lower spring receiver and must accommodate an axial shock absorber. Lift spacers are presently available, typically in 2″ and 3″ lift sizes, however known spacers require special casting and/or expensive machining. It would be desirable to provide such a suspension lift which is simple in design, made from readily available plate and cylinder stock, requires no expensive machining, and is sufficiently rugged for its intended use. U.S. Pat. No. 3,830,482, issued Aug. 20, 1974, to Norris describes an adjustable coil spring lifter to provide lift or restore loaded spring height. U.S. Pat. No. 6,149,171, issued Nov. 21, 2000, to Bono et al. describes a coil spring isolator for a vehicle suspension. U.S. Pat. No. 6,188,039, issued Feb. 13, 2001, to Gass, describes a projection welded panel spacer and the method for making the spacer by welding flats to tube stock. U.S. Pat. No. 6,481,071 B1, issued Nov. 19, 2002, to Newhan, describes a suspension kit to raise a vehicle front end. U.S. Pat. No. 6,543,828 B1, issued Apr. 8, 2003, to Gass, describes a welded panel spacer and method of making the spacer. U.S. Pat. No. 6,642,471 B2, issued Nov. 4, 2003, to Imai et al., describes a method for welding steels including plate to cylindrical stock. Internet Website http://Performancelifts.com describes a Daystar 02-24 Ram 1500 2″ lift spacer. Internet Website http://www.daystarweb.com describes front coil spring spacer kits for Dodge Ram 1500 suspensions. Internet Website http://rough.roughcountry.com of Rough Country a division of Heckethorn Products, Inc. is a source for a coil spring spacer for Dodge Ram 1500 suspensions (See FIG. 5 of the instant application). None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus a vehicle suspension lift spacer for Dodge Ram 1500 trucks solving the aforementioned problems is desired. | <SOH> SUMMARY OF THE INVENTION <EOH>The vehicle suspension lift spacer of the present invention is designed to fit between the upper end of the coil spring and the upper spring receiver of the front suspension of a Dodge Ram 1500 truck. It is made by cutting and welding stock flat and cylinder stock material, making it cheap to make and sufficiently rugged for the desired use. No special casting or machining is required. The lift spacer is generally cylindrical, having a central axis in common with the axially mounted shock absorber extending downward therethrough. The lift spacer has an upper attachment plate in the shape of a flat ring having equally spaced bolts extending upward for attachment through the upper coil spring receiver and shock tower mounts. The lift member is a cylindrical section of appropriate length and is welded coaxially to the underside of the upper attachment plate. A bearing plate in the shape of a flat ring is coaxially welded to the lower edge of the cylindrical lift member for bearing against the upper end of the coil spring. A cylindrical guide member is welded to and coaxially depends from the lower side of the bearing plate to maintain the lift member properly placed relative to the outer coil spring and the inner shock absorber. The spacer may be provided in desired lengths, and typically 2″ and 3″ lengths. The desired length is obtained by selecting the length of the cylindrical section, the thickness of the upper attachment plate and bearing plate remaining a constant. The lift spacer may be made from steel or other appropriate material. It is an aspect of the invention which provides improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. These and other aspects of the present invention will become readily apparent upon further review of the following specification and drawings. | 20040412 | 20061121 | 20051013 | 91928.0 | 1 | WEBB, TIFFANY LOUISE | VEHICLE SUSPENSION LIFT SPACER | MICRO | 0 | ACCEPTED | 2,004 |
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10,822,081 | ACCEPTED | Surgical instrument | An endoscopic or laparoscopic instrument includes a distal tool, a rigid or flexible elongated shaft that supports the distal tool, and a proximal handle or control member, where the tool and the handle are coupled to the respective distal and proximal ends of the elongated shaft via bendable motion members. The tool and the tool motion member are coupled to the handle and the handle motion member via cables and a push rod in such a way that the movement of the handle with respect to the elongated shaft in any direction is replicated by the tool at the distal end of the shaft. The magnitude of the tool motion with respect to the handle motion may be scaled depending on the size of the handle motion member with respect to that of the tool motion member. | 1. A surgical instrument comprising: an elongated instrument shaft having proximal and distal ends; a tool disposed from the distal end of the instrument shaft; and a control handle disposed from the proximal end of the instrument shaft; said tool being coupled to the distal end of said elongated instrument shaft via a first movable member; said control handle coupled to the proximal end of said elongated instrument shaft via a second movable member; whereby movement of said control handle with respect to said elongated instrument shaft via said second movable member causes attendant movement of said tool with respect to said elongated instrument shaft via said first movable member; wherein at least one of said first and second members comprises a bendable motion member. 2. The surgical instrument of claim 1 further including a control element that intercouples between said first and second movable members so that a movement of the control handle at the second movable member causes a movement of tool via the first movable member. 3. The surgical instrument of claim 2 wherein said control element comprises a cable system that interconnects the first and second movable members, said cable system being actuated by the movement of the control handle to, in turn, move the tool. 4. The surgical instrument of claim 1 wherein each of the movable members have two degree of freedom to provide motion in all directions. 5. The surgical instrument of claim 1 wherein both of the movable members comprise a bendable motion member, each bendable motion member providing at least one degree of freedom and the bending stiffness of the second movable member is greater than the bending stiffness of the first movable member. 6. The surgical instrument of claim 5 wherein each of the bendable motion members have two degree of freedom to provide motion in all directions. 7. The surgical instrument of claim 5 wherein the control handle comprises a push-pull tool actuation arrangement. 8. The surgical instrument of claim 1 wherein the tool movement with respect to the distal end of the elongated shaft is in the opposite direction of the control handle movement with respect to the proximal end of the elongated shaft. 9. The surgical instrument of claim 1 wherein the tool movement with respect to the distal end of the elongated shaft is in the same direction of the control handle movement with respect to the proximal end of the elongated shaft. 10. The surgical instrument of claim 1 wherein the control handle comprises a pull-pull tool actuation arrangement. 11. The surgical instrument of claim 1 wherein the elongated instrument shaft includes at least a flexible segment thereof. 12. The surgical instrument of claim 1 wherein the tool is selected from a group comprising a jaw, gripper, clip applier, stapler, electrosurgery device, scalpel and scissors. 13. The surgical instrument of claim 1 further including another proximal movable member and another distal movable member for multi-modal controlled movement of the tool. 14. The surgical instrument of claim 1 wherein the second movable member is able to axially rotate about the control handle. 15. The surgical instrument of claim 1 further including a distal axial rotation joint for axially rotating the first movable member about the elongated shaft. 16. The surgical instrument of claim 1 further including a distal axial rotation joint for axially rotating the tool about the first movable member. 17. The surgical instrument of claim 1 further including distal and proximal rotation joints wherein the proximal axial rotation joint actuates the distal axial rotation joint. 18. The surgical instrument of claim 1 further including a motion member locking mechanism for releasably locking said movable members. 19. The surgical instrument of claim 1 further including an electromechanical actuator for driving at least one degree of freedom movement of the tool. 20. A surgical instrument comprising: an elongated instrument shaft having proximal and distal ends; a tool disposed from the distal end of the instrument shaft; and a control handle disposed from the proximal end of the instrument shaft; said tool being coupled to the distal end of said elongated instrument shaft via a movable member; said control handle coupled to the proximal end of said elongated instrument shaft via a torque sensing member; an electromechanical actuator coupled to said movable member; wherein torque applied at said torque sensing member by the operator produces a proportional movement of said actuator, which in turn produces a movement of said tool with respect to said elongated instrument shaft via said movable member. | BACKGROUND OF THE INVENTION The present invention relates in general to surgical instruments, and more particularly to manually operated surgical instruments that are intended for use in minimally invasive surgery. Endoscopic and laparoscopic instruments currently available in the market are extremely difficult to learn to operate and use, mainly due to a lack of dexterity in their use. For instance, when using a typical laparoscopic instrument during surgery, the orientation of the tool of the instrument is solely dictated by the locations of the target and the incision, which is often referred to as the fulcrum effect. As a result, common tasks such as suturing, knotting and fine dissection have become challenging to master. Various laparoscopic instruments have been developed over the years to overcome this deficiency, usually by providing an extra -articulation often controlled by a separately disposed knob. However, even with these modifications these instruments still do not provide enough dexterity to allow the surgeon to perform common tasks such as suturing at any arbitrarily selected orientation. Accordingly, an object of the present invention is to provide a laparoscopic or endoscopic surgical instrument that allows the surgeon to manipulate the tool end of the surgical instrument with greater dexterity. SUMMARY OF THE INVENTION In accordance with one aspect of the present invention there is provided an endoscopic or laparoscopic instrument that is comprised of a distal tool, a rigid or flexible elongated shaft that supports the distal tool, and a proximal handle or control member, where the tool and the handle are coupled to the respective distal and proximal ends of the elongated shaft via pivoted or bendable motion members. The tool and the tool motion member are coupled to the handle and the handle motion member via cables and a push rod in such a way that the movement of the handle with respect to the elongated shaft in any direction are replicated by the tool at the distal end of the shaft. The magnitude of the tool motion with respect to the handle motion may be scaled depending on the size of the handle motion member with respect to that of the tool motion member. In the present invention one embodiment of the tool motion member is a bending section that is bendable in any arbitrary angle thereby providing two degrees of freedom, whereas in another embodiment, the tool motion member is comprised of the combination of a single plane bendable section and a pivotal joint. In still another embodiment, the motion member is comprised of two pivotal joints orientated orthogonal to each other. In addition to these embodiments where the motion member provides two degrees of freedom, in a situation where less dexterity is needed, the motion member can only be a one degree of freedom member, either pivotal or bendable. In accordance with another aspect of the invention there is provided a manually operated surgical instrument primarily adapted for use in minimally invasive surgery. The instrument comprises an elongated instrument shaft having proximal and distal ends; a proximal turnable member; a control handle coupled to the proximal end of the elongated instrument shaft via the proximal turnable member; a distal turnable member; a surgical tool coupled to the distal end of the elongated instrument shaft via the distal turnable member; and a transmission element that intercouples between the proximal and distal turnable members so that a deflection of the control handle at the proximal turnable member causes a deflection of surgical tool via the distal turnable member. In accordance with still another aspect of the invention there is provided a manually operated surgical instrument primarily adapted for use in minimally invasive surgery. The instrument comprises an elongated instrument shaft having proximal and distal ends; a tool disposed from the distal end of the instrument shaft; and a control handle disposed from the proximal end of the instrument shaft. The tool is coupled to the distal end of the elongated instrument shaft via a first movable member. The control handle is coupled to the proximal end of the elongated instrument shaft via a second movable member. The movement of the control handle with respect to the elongated instrument shaft via the second movable member causes attendant movement of the tool with respect to the elongated instrument shaft via the first movable member. BRIEF DESCRIPTION OF THE DRAWINGS Numerous other objects, features and advantageous of the invention should now become apparent upon a reading of the following detailed description taken in conjunction with the accompanying drawings in which: FIG. 1 is a side view of a schematic diagram of a surgical instrument in accordance with the present invention; FIG. 2 is a plan view of the instrument shown in FIG. 1; FIG. 3 shows the instrument of FIG. 1 illustrating the roll of the control handle and the attendant roll of the tool end; FIG. 4 is a view like that shown in FIG. 1 and additionally illustrating a cabling scheme that can be used in the surgical instrument; FIG. 5A schematically illustrates a bendable section of ribbed construction; FIG. 5B schematically illustrates a bendable section of bellows construction; FIG. 5C is a cross-sectional view through a tool motion member illustrating the motion control cables and the tool actuation push rod; FIG. 6 is a schematic diagram like that shown in FIG. 1 but where the handle to tool motion is opposite to that illustrated in FIG. 1; FIG. 7A is a schematic diagram of a tool push-pull arrangement that employs a four bar mechanism; FIG. 7B is a schematic diagram of a tool push-pull arrangement that employs a camming slot mechanism; FIG. 7C is a schematic diagram of a handle push-pull arrangement that employs a palm grip based upon a four bar mechanism; FIG. 7D is a schematic diagram of a handle push-pull arrangement that employs a pistol grip handle; FIG. 8A is a side view of a schematic diagram of a surgical instrument in accordance with another embodiment the present invention where the tool motion member is comprised of two pivotal joints orientated orthogonal to each other while the handle motion member is bendable in any directions, as in previously described embodiments; FIG. 8B is a plan view of the instrument shown in FIG. 8A; FIG. 8C is a cross-sectional view through the handle motion member of FIG. 8A illustrating the motion control cables and the tool actuation push rod; FIG. 9A is a side view of a schematic diagram of a surgical instrument in accordance with still another embodiment the present invention where the tool motion member comprises a pivotal pitch joint as in the previous embodiment (FIG. 8A) but with a bendable section instead of the pivotal joint for the yaw motion; FIG. 9B is a plan view of the instrument shown in FIG. 9A; FIG. 10A is a schematic diagram of the pivotal pitch jaws and the control handle mechanism that may be used with the embodiments of FIGS. 8A and 9A; FIG. 10B is a schematic diagram of the mechanism of FIG. 10A showing the upper handle controlling the lower jaw; FIG. 10C is a schematic diagram of the mechanism of FIG. 10A showing the lower handle controlling the upper jaw; FIG. 10D is a schematic diagram of the mechanism of FIG. 10A illustrating a midline axis of the jaws and the associated control by the bending of the handle motion member; FIG. 11A is a schematic diagram showing an embodiment with yaw motion-only bending members for both the tool and handle motions where pivotal pitching motion of the handle controls pivotal pitching motion of the tool; FIG. 11B is a plan view of the instrument shown in FIG. 11A; FIG. 12 is a schematic diagram showing an embodiment with one pivotal tool motion joint, one bendable tool motion section, and two pivotal handle motion joints; FIG. 13 is a schematic diagram showing an embodiment with two tool motion pivots, and with one bendable section and one pivotal handle motion member; FIG. 14 is a schematic diagram of a further embodiment of the invention in which the instrument shaft, between control and working ends of the instrument, is flexible so as to conform to the shape of an anatomic channel or lumen; FIG. 15 is a schematic diagram similar to that shown in FIG. 14 where multiple motion members are placed along the length of the elongated instrument shaft for multi-modal controlled movement of the tool; FIG. 16 is a schematic diagram of another embodiment of the present invention in which an axial torque rotation and transmission mechanism is employed; FIGS. 17A and 17B are schematic diagrams relating to FIG. 16 showing alternate embodiments utilizing axial rotation joints at both control and tool ends of the instrument; FIG. 18 shows an embodiment in which the tool motion control cables and grip actuation rod are driven an by electrical motors mounted on the side of the proximal end of the elongated instrument shaft instead of being driven directly by the handle motion member and handle; FIG. 19 is a schematic diagram of an alternate embodiment related to FIG. 18 and that illustrates an arrangement where the motors are situated away from the handle via mechanical cables traveling through the flexible conduit; FIG. 20 is a schematic diagram of another embodiment of the invention with multiple motion members, effectuating the forward/backward linear motion by means of a linear actuator to aid the forward/backward motion; FIGS. 21A, 21B and 21C are separate views showing a more detailed embodiment of the invention in different positions of the handle and tool; FIG. 22A is a fragmentary perspective view of the tool end of the instrument illustrated in FIG. 21; FIG. 22B is a longitudinal cross-sectional view of the tool end of the instrument as illustrated in FIGS. 21 and 22A; FIG. 22C is an exploded perspective view of the instrument segment illustrated of FIG. 22A; FIG. 23A is a fragmentary perspective view of the handle end of the instrument illustrated in FIG. 21; FIG. 23B is a longitudinal cross-sectional view of the handle end of the instrument as illustrated in FIGS. 21 and 23A; FIG. 23C is an exploded perspective view of the instrument segment illustrated of FIG. 23A; FIG. 23D is a cutaway perspective view of the bendable section of the instrument at the handle end; FIG. 24 illustrates another embodiment of the present invention where the movement of the tool motion member is controlled by the torque applied at the handle motion member; FIG. 25 is still a further embodiment of the present invention relating to FIG. 24; FIG. 26 is a further embodiment of the present invention where ease of use of the instrument is further enhanced by making it simpler to roll the tool end about its axis, an essential motion in suturing at off-axis angle; and FIG. 27 illustrates still another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION FIGS. 1 and 2 show respective side and top views of one embodiment of the present invention. Both the tool and the handle motion members are bendable in any directions, and they are connected to each other via cables in such a way that the tool motion member bends in the opposite direction of the handle motion member, thereby creating a sensation that the tool always points in generally the same direction as the handle. Although FIGS. 1 and 2 shows only the side and top views where only pitch and yaw motions are actuated, respectively, it should be noted that the handle motion member could be bent in any direction, actuating the tool motion member to bend in directly opposite directions, and in the same plane. Herein these motion members are also referred to as turnable members. In addition, unlike mechanisms that are comprised of pivotal joints, the bendable motion members can bend in any direction without any singularity. As a result, as shown in FIG. 3, the surgeon is be able to roll the instrument tool 18 about its longitudinal axis 11 at any orientation simply by rolling the handle, a desirable motion for suturing in off-axis. Regarding FIGS. 1-3, there is disclosed an instrument that is comprised of an elongated instrument shaft 10 supporting, at its proximal end, the handle 12 connecting with the handle motion member 14. At the distal end of the instrument shaft there is disposed the tool motion member 16 that couples to the tool or end effector 18, shown in FIG. 1 as a set of jaws. It is understood that other types of tools may also be substituted for the jaw set that is illustrated. In FIGS. 1 and 2 one position is shown in solid outline and an alternate position is shown in dotted outline. These two different positions are also illustrated by the double-headed motion arrow 7 indicating motion of the handle 12 and the double-headed motion arrow 8 indicating corresponding motion of the tool 18. In the descriptions set out herein the term “bendable section”, “bendable segment”, “bendable motion member”or “turnable member”refer to an element of the instrument that is controllably bendable in comparison to an element that is pivoted. The bendable elements of the present invention enable the fabrication of an instrument that can bend in any direction without any singularity, and that is further characterized by a ready capability to bend in any direction, all with a single unitary structure. A definition of these bendable motion members is—an instrument element, formed either as a controlling means or a controlled means, and that is capable of being constrained by tension or compression forces to deviate from a straight line to a curved configuration without any sharp breaks or angularity—. FIG. 3 also illustrates the roll of the instrument made possible by the interaction between the control handle 12 and tool 18, and their respective motion members 14 and 16. The instrument shaft is shown positioned through the incision or aperture 22 in the abdominal wall 20. This rolling action is also illustrated in FIG. 3 by the series of circular arrows that include arrow 24 illustrating the rotation or rolling of the handle 12 about axis 9 to cause a corresponding rotation or rolling of the tool 18 about axis 11, illustrated by the circular arrow 26. Similarly, the instrument shaft 10 is rotated at the same time, as illustrated by the arrow 28 in FIG. 3. Reference is now made to FIG. 4 that illustrates the internal cabling scheme of the embodiment disclosed in FIGS. 1-3. In FIG. 4 the same reference characters are used as in FIGS. 1-3 to identify like elements. The control cables 30A and 30B run parallel to each other along the longitudinal direction of the instrument shaft 10 and they are terminated, respectively, at the proximal and distal ends of the handle and tool motion members. The termination is shown at each point 29 in FIG. 4 and represents a location where the cable is fixed at each end thereof to the respective handle and tool structures. Although only two motion member control cables 30A and 30B are shown in the FIG. 4, it should be noted that three or more cables are preferred in order to actuate the tool motion member in any direction. As illustrated in FIG. 4, as an example, when the handle 12 is tilted upwardly by bending the handle motion member 14 upwardly, the proximal end of the cable 30B is pulled while the cable 30A is relaxed. As a result, the distal end of the cable 30B is shortened causing the tool motion member 16 to bend downwardly resulting in a pitching down motion of the tool 18, as illustrated in FIG. 4. In addition to the motion control cables 30A and 30B, FIG. 4 also illustrates the tool actuating push rod 32 that runs through the center of the motion members 14, 16 and the elongated shaft 10 so that the tool actuation is decoupled from the bending motions of the motion members. Since the sections of the push rod 32 that go through the tool and handle motion members 14, 16 need to bend, the rod 32 needs to be somewhat flexible, and in order to prevent these sections from buckling, they are preferably confined in a conduit or a channel. See the more detailed embodiment in FIGS. 21-23. Alternatively, the section of push rod 32 that does not need to bend may be reinforced to prevent it from buckling. The proximal and distal ends of the push rod 32 are connected to the push-pull handle and jaw mechanisms, respectively (shown in FIGS. 7A-7D). The bendable handle and tool motion members 14, 16, such as illustrated in FIG. 4 can be constructed in many different embodiments. Refer, for example, to FIGS. 5A and 5B for an illustration of two possible embodiments showing two degrees of freedom (DOF) bending motion members. FIG. 5A shows a ribbed construction that includes alternating ribs 13 and slots 15 disposed about the center column 17. The push rod 32 is disposed at the center of the center column 17. The control cables 30A, 30B extend through the outer portions of the ribs 13. FIG. 5B shows a bellow construction 13A including a center column 17A which accommodates the push rod 32 at its center. The control cables 30A, 30B extend through the bellows construction 13A. In both cases of FIGS. 5A and 5B, and, as shown in the cross-sectional view of FIG. 5C, the motion control cables 30 extend along the outer edge whereas the push rod 32 is centered along the center column 17. The center column 17, which acts as a conduit for the somewhat flexible push rod 32, is relatively stiff longitudinally (high column strength) in order to maintain the overall length of the motion cable pathways constant, while maintaining lateral flexibility for bending. It should be noted that a variety of geometries may be employed for the bending motion member construction for improved lateral flexibility and column/torsion stiffness. FIG. 6 illustrates another embodiment of the present invention where the axial orientation of the handle with respect to the elongated instrument shaft is changed. In this embodiment, the surgeon, before or in the middle of the surgical procedure, may unlock, rotate axially and then lock back the handle onto the elongated instrument shaft. In FIG. 6 the same reference characters are used as in FIG. 4 to designate like elements. Regarding FIG. 6, there is disclosed an instrument that is comprised of an elongated instrument shaft 10 supporting, at its proximal end, the handle 12 connecting with the handle motion member 14. At the distal end of the instrument shaft there is disposed the tool motion member 16 that couples to the tool or end effector 18, shown as a set of jaws. In FIG. 6, because the handle has been rotated, the control cables 30A and 30B are shown in a crossed orientation. Also, terminations are used on the cable ends as shown before in FIG. 4. As illustrated in FIG. 6, the handle motion member 14 may be axially rotatable 180 degrees from its normal orientation, such as was previously illustrated in FIG. 4. This is illustrated in FIG. 6 by the rotation arrow 35 that is shown extending about the rotation and locking member 35A, which slides in the direction of arrow 35B to lock and unlock the axial orientation of the handle motion member 14 with respect to that of the elongated shaft 10. As a result, when the handle is tilted upwardly, cable 30A is pulled instead of cable 30B, therefore, pitching the tool upwardly rather than downwardly, as shown in FIG. 6. This feature may be very useful when the surgeon's hand is in awkward position. FIGS. 7A-7D illustrate some examples of push-pull jaw and handle mechanisms that may be employed with the present invention. For example, FIGS. 7A and 7B show two jaw constructions, one based on a four bar mechanism and the other based on a camming slot mechanism. It is noted that, in addition to the illustrated embodiments, a wide variety of similar push-pull or other mechanisms may be readily adapted to the tool end of the instrument of the present invention. For instance, one can adapt a stapler or clip applier tool to this invention. In addition to tool configurations described above, energy delivering tools such as monopolar, bipolar and electrocautery tools and non-actuated tools such as a scalpel or monopolar j-hook can be readily employed. FIG. 7A schematically illustrates the four bar mechanism 36 operated from the push rod 32 and coupling to the jaws 18A at the jaw axis 19. FIG. 7B schematically illustrates the camming slot mechanism 38 operated from the push rod 32 and coupling to the jaw arrangement 18B. In either case the linear translation of the push rod 32, indicated by the double headed arrow 37, controls the opening and closing of the jaws. Similarly, FIGS. 7C and 7D show two examples of common push-pull handle designs; a palm grip in-line handle 40 including a bar mechanism 42 shown in FIG. 7C, and a pistol grip handle 44 shown in FIG. 7D. Again, a wide variety of similar push-pull handle designs may be employed. FIG. 7C illustrates the bar mechanism controlled from the handle 40 to actuate the push rod 32. FIG. 7D illustrates the pistol grip handle 44 for controlling the push rod 32. Double headed arrows 41 indicate the motion occasioned by the handle control on the push rod. FIGS. 7C and 7D also respectively show bellows type wrists 14A and 14B for facilitating corresponding tool motion. FIGS. 8A, 8B and 8C illustrate another embodiment of the present invention where the tool motion member is comprised of two pivotal joints (pitch and yaw axis) orientated orthogonal to each other while the handle motion member is bendable in any direction, as in previously described embodiments. This embodiment relies on independent pitch motions of each jaw of the tool to provide both the jaw grasping and pitch motion, and therefore, it uses two pairs of pitch motion control cables as shown in FIG. 8C. As in previous embodiments, tilting of the handle in the up/down directions causes respective pitching down/up of the tool (FIG. 8A), and the side-to-side motion of the handle results in yaw motion of the tool (FIG. 8B). The motion at any one point in time is usually a combination of pitch and yaw motions. Regarding FIGS. 8A-8C, there is disclosed an instrument that is comprised of an elongated instrument shaft 50 supporting, at its proximal end, the handle 52 connecting with the handle motion member 54. At the distal end of the instrument shaft there is disposed the tool motion member 56 that couples to the tool or end effector 58, shown as a set of jaws. It is understood that other types of tools may also be substituted for the jaw set that is illustrated. The side view of FIG. 8A and the plan view of FIG. 8B illustrate the handle motion member as being bendable (a bendable section or segment), as in previous embodiments that have been described. However, the tool motion member 56 is comprised of two separate pivot joints orientated orthogonal to each other while the handle motion member is bendable in any direction. The yaw pivot joint is defined at yaw pivotal axis 55, while the pitch pivot joint is defined at pitch pivotal axis 57, one disposed orthogonal to the other. This embodiment uses two pairs of pitch motion control cables 53, and one pair of yaw motion control cables 51, as shown in the cross-sectional view of FIG. 8C. FIGS. 9A and 9B show still another embodiment of the tool motion member with a pivotal pitch joint as in the previous embodiment (FIGS. 8A-8C) but with a bendable member 55A instead of the pivotal joint for the yaw motion. As illustrated in FIGS. 9A and 9B, the bendable member 55A bends only in a side-to-side plane (in the plane of the paper in FIG. 9B) providing only the yaw motion of the tool. The pitch motion control cables 53 extend through the central plane of the yaw motion bending section 55A so that the pitch and grip motion of the jaws are decoupled from the yaw motion. The pitch motion control cables 53 control the pivoting at axis 57. FIG. 10A is a schematic diagram of the pivotal pitch jaws and the control handle mechanism that may be used with the embodiments of FIGS. 8A and 9A. FIG. 10B is a schematic diagram of the mechanism of FIG. 10A showing the upper handle controlling the lower jaw. FIG. 10C is a schematic diagram of the mechanism of FIG. 10A showing the lower handle controlling the upper jaw. FIG. 10D is a schematic diagram of the mechanism of FIG. 10A illustrating a midline axis of the jaws and the associated control by the bending of the handle motion member. In FIGS. 10A, 10B and 10C, there is described an example of a cabling/handle mechanism for a set of jaws, and in which the jaws have pivotal pitch motion, as in FIGS. 8 and 9. There are two jaw capstans 60 and two handle capstans 64 as shown in FIGS. 10A-10C. FIG. 10B illustrates the upper handle 66A controlling the lower jaw 18A via the capstan 64A. Alternatively, FIG. 10C illustrates the lower handle 66B controlling the upper jaw 18B via the capstan 64B. FIGS. 10A-10C also show the corresponding cable loops 68 one associated with each jaw. FIG. 10B depicts the cable loop 68A extending about the capstan 64A, through the bendable member 65 and to the jaw capstan 60A for control thereof. FIG. 10C depicts the cable loop 68B extending about the capstan 64B, through the bendable member 65 and to the jaw capstan 60B for control thereof. The distal end of each of the pitch motion control cable loops 68A, 68B is terminated at the jaw capstan 60A, 60B, and the proximal end of each of the pitch motion control cable loops 68A, 68B is terminated at the handle capstan 64A, 64B. Each handle 66A, 66B is firmly attached to its associated handle capstan 64A, 64B, and the handle capstans are arranged to form a four bar mechanism 61 where the sliding member 63 thereof is constrained to a linear motion along the longitudinal axis of the base 69 of the handle. In FIGS. 10A-10C the various element motions are depicted by double headed arrows; arrows 70 depicting the handle motion; arrows 71 depicting the linear slider motion; arrows 72 depicting the capstan rotation motion; and arrows 73 depicting the jaw rotation occasioned by the jaw capstan rotation motion. FIG. 10D illustrates the embodiment of FIG. 10A, the motion of the handles at their midline 70A and the corresponding motion of the jaws at their midline 73A. The pitching motion or rotation of the midline 73A of the jaws is controlled by the bending up/down movement of the handle motion member 65. The opening and closing of the handles 66A, 66B relative to midline 70A controls the jaw opening and closing with respect to the jaws midline 73A, as illustrated in FIG. 10D. The embodiments described so far have employed a handle motion member arrangement that is bendable in any directions. However, just as a variety of tool motion members can be employed, other handle motion types can also be used. For example, FIGS. 11A and 11B show an embodiment with a yaw motion-only bending member for both the tool and handle motion members while pivotal pitching motion of the handles controls pivotal pitching motion of the tool. FIG. 11A is a schematic diagram showing an embodiment with yaw motion-only bending members for both the tool and handle motions where pivotal pitching motion of the handles controls pivotal pitching motion of the tool. FIG. 11B is a plan view of the instrument shown in FIG. 11A. Regarding FIGS. 11A and 11B, there is disclosed an instrument that is comprised of an elongated instrument shaft 80 supporting, at its proximal end, a handle 82 connecting with a handle motion member 84. The handle 82 is depicted as a hand-held scissors type handle that may be moved in the direction indicated by double headed arrow 81. At the distal end of the instrument shaft 80 there is disposed a tool motion member 86 that couples to a tool or end effector 88, shown in FIG. 11A as a set of jaws. The handle motion member 84 may be considered as comprised of two components including a bendable segment 83 and a pivotal joint 85. The bendable segment 83 is limited in motion so as to control only yaw motion of the handle. This yaw motion is illustrated by the double headed arrow 81A in FIG. 11B. The pitch motion is defined as motion about pivotal joint 85. This pitch motion is illustrated by the double headed arrow 81 in FIG. 11A. Similarly, at the distal end of the instrument the tool motion member 86 may be considered as comprised of two components including a bendable segment 87 and a pivotal joint 89. The bendable segment or section 87 is limited in motion so as to control only yaw motion of the tool. This yaw motion is illustrated by the double headed arrow 91A in FIG. 11B. The pitch motion is defined as motion about pivotal joint 89. This pitch motion is illustrated by the double headed arrow 91 in FIG. 11A. FIGS. 11A and 11B also depict the control cables for both pitch and yaw. These are illustrated as pitch motion control cables 92 and yaw motion control cables 93. There is preferably a pair of yaw motion control cables and two pairs of pitch motion control cables, one for each jaw. Other tool and handle motion joint combinations can also be considered as illustrated in FIGS. 12 and 13. In these figures there is disclosed an instrument that is comprised of an elongated instrument shaft 100 supporting, at its proximal end, a handle 102 connecting with a handle motion member 104. In both embodiments the handle 102 is depicted as a hand-held scissors type handle that may be moved in the direction indicated by double headed arrow 101. At the distal end of the instrument shaft 100 there is disposed a tool motion member 106 that couples to a tool or end effector 108, shown in FIGS. 12-14 as a set of jaws. FIG. 12 shows an embodiment with the tool and handle motion members 106,104 comprised of one pivotal tool motion joint 106A, one bendable section 106B and two pivotal handle motion joints, respectively. FIG. 13 illustrates an embodiment with two pivotal tool motion joints 109, one bendable section 104A at the handle, and one pivotal handle motion joint 104B. The embodiments described thus far have shown the elongated shaft to be rigid, however, in other embodiments of the invention the shaft may be an elongated flexible shaft. One such embodiment is shown in FIG. 14. The flexible elongated shaft section 110 is generally passive, conforming to the shape of an anatomic channel or body lumen, illustrated in FIG. 14 at 113. There is disclosed an instrument that is comprised of an elongated flexible instrument shaft 110 supporting, at its proximal end, the handle 112 connecting with the handle motion member 114. At the distal end of the flexible instrument shaft 110 there is disposed the tool motion member 116 that couples to the tool or end effector 118, shown in FIG. 14 as a set of jaws. In addition, one could also have embodiments where multiple motion members are placed along the length of the elongated shaft for multi-modal controlled movement of the tool, as illustrated in FIG. 15. In FIG. 15 some of the same reference characters are used as used in FIG. 14. Thus, this embodiment includes an elongated flexible instrument shaft 110 supporting, at its proximal end, the handle 112 connecting with the handle motion member 114. At the distal end of the instrument there is disposed the tool motion member 116 that couples to the tool or end effector 118, shown in FIG. 15 as a set of jaws. FIG. 15 shows the added bendable sections, bendable segments or bendable motion members 117 and 119 directly at opposite ends of the flexible section 110. The interconnection between the members 116 and 117 may also be a flexible section. Likewise, the interconnection between the members 114 and 119 may be a flexible section. The handle motion members 114 and 119 may be cabled to control the motion of the tool motion members 116 and 117, respectively, or vice versa. In some applications such as in lower GI procedures, the elongated shaft may bend at multiple points, and transmitting axial rotational motion about the shaft may be difficult. In such cases, it is more effective to employ a torque transmission mechanism, as illustrated schematically in FIG. 16. FIG. 16 schematically illustrates an axial rotation transmission mechanism that has a tool end 120 and a control handle end 122. A rotation at the handle end 122 converts into a like rotation of the instrument at the tool end 120. This rotation is indicated by the respective arrows 121 and 123. FIGS. 17A and 17B show embodiment of the instrument of the present invention that utilize the schematic concepts of FIG. 16. In FIG. 17 some of the same reference characters are used as used in FIG. 14. Thus, this embodiment includes an elongated flexible instrument shaft 110 supporting, at its proximal end, the handle 112 connecting with the handle motion member 114. At the distal end of the instrument there is disposed the tool motion member 116 that couples to the tool or end effector 118, shown in FIGS. 17A and 17B as a set of jaws. In the embodiment shown in FIG. 17A, there is an axial rotation joint 111 between the proximal end of section 110 and the handle motion member 114, and likewise, there is an axial rotation joint 115 between the more distal end of the section 110 and the tool motion member 116. On the other hand, in the embodiment shown in FIG. 17B, the axial rotation joint 111 is situated between the handle motion member 114 and the handle 112 whereas the axial rotation joint 115 is situated between the tool motion joint 116 and the tool 118. In both cases, these axial rotation joints are interconnected so that rotation of joint 111 causes a corresponding rotation of joint 115. The elongated flexible shaft 110 preferably does not rotate axially itself. The motions of the tool and the actuation via the grip can also be controlled by actuators such as electrical motors as shown schematically in FIGS. 18 and 19. In the embodiment shown in FIG. 18, the tool motion control cables 124 and grip actuation rod are driven by electrical motors 125 mounted on the side of the proximal end of the elongated shaft 126, instead of being driven directly by the handle motion member and associated handle. The pitch, yaw and roll motion of the handle is measured by respective rotational sensors such as potentiometers or encoders, and the on-board motion controller (not shown) sends appropriate commands to the motors based on the handle position information. In addition to the features of purely mechanical solutions, this embodiment provides additional benefits such as joint motion scaling, tremor reduction, etc. As an alternate-embodiment, FIG. 19 illustrates an arrangement where the motors 128 are situated away from the handle via the mechanical cables 129 traveling through a flexible conduit. The main benefit of this embodiment is lighter weight and the ability to plug in multiple kinds of instrument to a single bank of motors, thus reducing the cost. Another potential usage of an actuator is shown in FIG. 20. In embodiments especially with multiple motion members, effectuating the forward/backward linear motion may be difficult as the handle motion members would tend to bend or rotate as well, and in such cases, a linear actuator 130 may be employed to aid the forward/backward motion. Various methods are possible for controlling the linear motion. A simple method could be using an input device such as a toggle switch or button. A somewhat more sophisticated method could be employing a force sensing element mounted on either the elongated shaft or the carriage of the linear actuator to detect the forward/backward force exerted by the surgeon. The force information would then be used by a motion controller to command the linear actuator appropriately. FIGS. 21 through 23 show detailed illustrations of the embodiment as described in FIGS. 1 through 5, where both the tool and the handle motion members 150, 151 are bendable in any direction. The motion members 150 and 151 are connected to each other via cables extending through the elongated rigid shaft 152 in such a way that the tool motion member bends in the opposite direction of the handle motion member, as illustrated in FIG. 21. FIGS. 21A, 21B and 21C are separate views showing the instrument in different positions of the handle and tool. FIG. 21A illustrates the handle and tool in line with each other and in line with the longitudinal axis 150A. FIGS. 21B and 21C illustrate the off-axis motion of the handle and tool. FIG. 21B illustrates the handle 154 bendable upwardly while the corresponding tool bends downwardly relative to axis 150A. FIG. 21C illustrates the handle 154 bendable downwardly while the corresponding tool bends upwardly relative to axis 150A. Of course, in all of the views of FIG. 21 motion can also occur in and out of the plane of the paper (both pitch and yaw). In FIG. 21, although the end effector 153 in the illustration is a needle holder jaw set, it should be noted that other types of tools may be used. Similarly, although the in-line handle 154 is shown in the illustration, it could be easily substituted by other types of handles as well. Different types of handle could be with or without an opening spring, with or without the finger loops, with or without a lock, with one or two handle bars, or with a pistol-grip instead of an in-line grip, or various combinations thereof. In FIG. 21 it is noted that the handle motion member 151 is generally of larger diameter than the tool motion member 150. Although this is a preferred arrangement, these diameters may be the same or have various other dimensional relationships therebetween. In the preferred embodiment the bendable sections 150 and 151 are illustrated as being slotted arrangements, however, they may also be of other form such as the bellows structure previously mentioned. FIGS. 22A, 22B and 22C further illustrate the tool or end effector 153 and the tool motion member 150 located at the distal end of the elongated rigid shaft 152. FIG. 22A illustrates a perspective view of the tool section where the tool motion member 150 is bent slightly. The bendable motion member 150 and the distal end of the rigid shaft 152 are illustrated as receiving the motion control cables 155 and the tool actuating push rod 156. The tool 153 is firmly fixed on the distal end of the tool motion member 150, and likewise, the proximal end the tool motion member 150 is firmly fixed on the distal end of the rigid shaft 152. The needle holder (tool 153) has only one jaw that opens in order to increase its grasping force, although the tool could also be provided with both jaws operable. The bottom jaw 161 is part of the jaw yoke 166, and therefore it is not movable with respect to the yoke. The movement of the push rod 156 causes the pin 164 to move along the slot 165 in the yoke 166, and as a result the top jaw 162 moves or pivots about the pin 167. Reference is now made to the cross-sectional view of the tool section, as illustrated in FIG. 22B. The push rod 156 is flexible at rod 157 in the portion that passes through the tool motion member 150 whereas the portion that is situated inside the rigid shaft 152 is preferably rigid. The flexible push rod 157 is fixedly coupled to the rigid push rod 156. The motion control cables 155 and the rigid push rod 156 are guided by and through the spacer 158 along their paths, and the distal ends of the motion control cables 155 are terminated at 160. The flexible portion of the push rod 157 passes through the center of the tool motion member 150 and the jaw yoke 166, and it terminates by being fixedly coupled to the termination block 163, which in turn carries the pin 164 that traverses along the camming slots 165 (jaw 161) and 169 (jaw 162). In order to increase the column strength of the tool motion member, a reinforcement thin-walled tube 159 made of stiff material such as PEEK (a polyethylene plastic) is used. The end plate 168 is placed between the tool motion member 150 and shaft 152 to prevent the reinforcement tube 159 from sliding out. It should be noted that depending on the material and geometry of the tool motion member, it may not be necessary to employ such reinforcement tube. FIG. 22C illustrates an exploded view of the tool section of FIG. 22A. As previously described, the motion control cables 155 are terminated at 160. Forward and backward movement of the rigid push rod 156 moves the termination block 163 and the pin 164 along the slot 165 of the bottom jaw 161. Since the pin 164 also rides in the slot 169 of the top jaw 162, forward and backward motion of the pin 164 respectively opens and closes the top jaw. While the tool actuation rod 156 is disposed at the center of the bendable motion member, the four cables 155 are disposed in a diametric pattern so as to provide the all direction bending. In FIG. 22C the tool motion member 150 is illustrated as being comprised of a series of ribs 150R that define therebetween a series of slots 150S, that together define alternating direction transverse slots. The ribs 150R extend from a center support that carries the actuation rod 156 and tube 159. The ribs 150R provide a support structure for cables 155. In the particular embodiment described in FIG. 22C between the ribs there is a pattern of staggered ridges 150T disposed at 90 degree intervals about the member. The cables 155 pass through the area of the motion member 150 where these ridges 150T are arranged. FIGS. 23A, 23B, 23C and 23D illustrate in detail the handle section located at the proximal end of the elongated shaft 152. FIG. 23A is a perspective view of the handle section where the handle motion member 151 is slightly bent. In FIG. 23A the same reference characters are used to identify like components previously described in connection with the tool end of the instrument. For example, four motion control cables 155 as well as the tool actuating push rod 156 travel through the handle motion member 151. The cables 155 control bending motion at the tool motion member while rod 156 controls tool actuation. The distal end of the handle motion member 151 is fixedly connected to the proximal end of the elongated shaft 152 via the handle motion member coupler 171, and similarly, the proximal end of the handle motion member 151 is fixedly mounted to the handle body 178 of handle 154. Reference is now made to the cross-section view of the handle section, as illustrated in FIG. 23B. As with the tool section, the tool actuating push rod 156 is flexible (flexible rod portion 173) in the portion that passes through the handle motion member 151 whereas the portion that is situated inside the rigid shaft 152 is preferably rigid. The flexible portion 173 is fixedly coupled to the rigid push rod 156. The motion control cables 155 travel through the outer edge of the handle motion member 151 and are terminated at 175. The four cables 155 are disposed in the same pattern as discussed previously regarding the tool section (see FIG. 22C). The flexible push rod 173 travels through the center of the handle motion member 151 and is terminated at the sliding block 181. Similarly to the tool motion member, a thin-walled reinforcement tube 174 is placed at the center lumen of the handle motion member 151 to increase the column strength of the handle motion member. An end plate 176 is placed between the coupler 171 and the handle motion member 151 to prevent the reinforcement tube 174 from sliding out. Depending on the material and geometry of the handle motion member, the reinforcement tube may not be necessary. Opening and closing of the handle bars 179 causes forward and backward movement of the sliding block 181 via the handle links 180, which in turn, via the rods 156, 157 and 173, causes the jaw to respectively open and close. The handle spring 182 biases the handle to be open normally which is typical of needle holders. For other types of jaws, it may not be desirable to have the bias spring. FIG. 23C further illustrates the handle section of the instrument. Note that the motion control cables 155 are situated on the outer edge of the handle motion member 151 and are terminated at 175, whereas the flexible push rod 173 passes through the handle motion member 151 at its center and terminates at the sliding block 181. The geometry of the handle motion member 151 in this embodiment is further illustrated in the cutaway view of the handle motion member, as shown in FIG. 23D. As discussed previously, the bendable tool and handle motion members can be constructed in many different embodiments such as a ribbed or bellowed construction. FIG. 23D illustrates the preferred embodiment of the handle motion member 151. Substantially the same construction is shown herein for the tool motion member 150. In FIG. 23D the bendable motion section is illustrated as having alternating slots 183A and 183B extending in transverse directions for allowing the motion member to bend in any direction while maintaining a continuous center region for high column strength. FIG. 23D illustrates the motion member as being comprised of a series of ribs 190R that define therebetween a series of slots 190S. The ribs 190R extend from a center support that carries the actuation rod 173 and tube 174. The ribs 190R provide a support structure for cables 155. In the particular embodiment described in FIG. 23D between the ribs there is a pattern of staggered ridges 190T that define the alternating slots and that are disposed at alternating 90 degree intervals about the member. The cables 155 pass through the area of the motion member 151 where these ridges 190T are. Reference has been made to the manner in which the instrument shown in FIGS. 21-23 can be manipulated to perform a surgical task. For example, FIG. 21 shows different positions of the instrument. These possible movements are brought about by the surgeon grasping the handle and bending or turning the handle virtually in any direction. For example, and in connection with FIG. 21C, the handle is illustrated as turned or tilted down with a corresponding turning or tilting of the tool section in an upward direction. In addition, by rotating the handle about the shaft the surgeon can tilt or turn the handle in and out of the plane depicted in FIG. 21C. Depending upon the direction of manipulation by the surgeon, the control cable 155 that is disposed closest in line to the direction of turning is loosened or slackened, and the opposite cable 155 is tightened. This action causes the opposite direction turning as depicted in FIG. 21. Essentially the tightened cable pulls the tool end in the opposite direction. By providing the four cable quadrant array of cables handle-to-tool action is in any direction. Another embodiment of the present invention is illustrated in FIG. 24 showing the instrument passing through an anatomic wall 207 at aperture 208. In this embodiment the movement of the tool motion member 205 is controlled by the torque applied at the handle motion member 202 rather than the movement of the member itself. Due to the fulcrum effect as well as usage of long elongated instruments, the surgeon often has to move the instrument handle in a wide range of motion during a particular medical procedure in order to perform the surgical task at the intended target area. As a result, the surgeon is often forced into very awkward postures, and manipulating the instrument handle further to control the tool motion member in those circumstances can be extremely difficult. In the embodiment of FIG. 24, the handle 201 is disposed at the proximal end of the elongated shaft 200 via the torque sensing member 202 which continuously measures the torque applied by the surgeon, as illustrated by the rotational torque arrow 204. Based on the torque measurement, the on-board motion controller (not shown) sends appropriate commands to the motors 203 for controlling the tool motion member 205. The torque sensing member 202 is preferably relatively stiff such that the movement of the handle 201 with respect to the elongated shaft 200 is minimal for reasons described above (to enhance surgeon manipulation). Tool actuation may be driven manually by the handle 201 itself as in FIG. 4 or it could be driven electronically by the motor as in FIG. 18. The motors could also be placed remotely as in FIG. 19. In the embodiment of FIG. 24 the handle end of the instrument is manipulated in substantially the same way as in earlier embodiments that have been described herein. FIG. 24 shows by arrow 204 the direction of motion at the handle end of the instrument, and the corresponding position of the tool 206, bent to the left in FIG. 24. In FIG. 24, instead of the motion member 205 being directly cable driven from the handle member, it is driven by cabling that couples from the control motors 203, which is in turn controlled from the torque sensing member 202. A full range of motion can be obtained from the instrument shown in FIG. 24 in all directions, as in earlier embodiments described herein. In the embodiment shown in FIG. 25, the benefit of the previous embodiment shown in FIG. 24 is, in essence, combined with the simplicity of the embodiment shown in FIGS. 1-4. As in the embodiment of FIGS. 1-4, the tool motion member 211 that couples to the tool 215 is disposed at the distal end of the instrument shaft 210. The handle 213 is disposed at the proximal end of the instrument. The handle 213 couples to the shaft 210 via the handle motion member 212, and both motion members 211 and 212 are bendable in any direction. In addition to what is illustrated in FIGS. 1-4, however, the embodiment in FIG. 25 simulates the effect of torque sensing member 202 of FIG. 24 by using a handle motion member 212 that is much larger in diameter and laterally stiffer than that of the tool motion member 211. Due to large diameter ratio between the motion members 211 and 212, small bending of the handle motion member 212 causes a substantial bending of the tool motion member 211. At the same time, because the handle motion member 212 is substantially stiff laterally, the surgeon operating the tool has to apply a reasonable amount of torque to the handle to cause the desired movement at the tool motion member. Without such lateral stiffness at the handle motion member, the tool motion member may bend too freely and may thus be difficult to control. Still another embodiment of the present invention is illustrated in FIG. 26 where ease of use of the instrument is further enhanced by making it simpler to roll the tool end about its axis 230, an important motion in suturing at an off-axis angle. Similar to the embodiment of FIGS. 1-4, FIG. 26 shows an instrument with an instrument shaft 220 and with the tool 223 and the handle 224 disposed respectively at the distal and proximal ends of the shaft 220, via motion members 221 and 222. However, unlike the embodiment of FIGS. 1-4, in this embodiment, the handle motion member 222 has a rolling-motion wheel 225 fixedly mounted at its proximal end, which is able to axially rotate about axis 232 and relative to the handle 224 as shown by the double-headed arrow 226. This action causes a corresponding rotation of the tool 223 about axis 230 and as illustrated by the double-headed arrow 228. Therefore, the surgeon operating the instrument can roll the instrument tool 223 simply by rolling the rolling-motion wheel 225 with his or her thumb rather than rolling the whole handle 224. Yet another embodiment of the present invention that further enhances ease of use is illustrated in FIG. 27. In addition to the embodiment of FIGS. 1-4, FIG. 27 also illustrates the motion member locking mechanism 234. While performing the surgical procedure, the surgeon operating the instrument may desire to lock the orientations of the bendable motion members temporarily so that he or she would not need to continuously exert torque at the handle motion member in order to maintain the desired orientation. The motion member locking mechanism 234 may consist of the locking collar 235, the locking wedge 236 and the cable guide 237. When the surgeon desires to lock the orientation of the motion member, he or she simply slides the locking collar 235 in the direction shown by the arrow 238, which then presses down the locking wedge 236 against the cable guide 237 with the control cables 233 pinched in between. Once pinched, the control cables 233 would not be able to move, and as a result, the orientations of the motion members 231 and 232 will be fixed. The motion member orientation lock can be released by sliding the locking collar 235 backward toward the instrument tip. There are several improvements brought forth by employing bendable sections for the motion members as opposed to other mechanisms such as pivotal joints or ball-and-socketjoints. A first important attribute of a bendable member is in its inherent lateral (bending) stiffness, especially when used for the proximal handle motion member. In a jointed arrangement the proximal joint is situated between the elongated shaft and the control handle, together with the fulcrum at the incision. This behaves as a “double-joint” and the instrument may have a serious tool stability issue if the joint is “free” to move. Suppose the operating surgeon slightly moves his/her wrist while holding the control handle of the instrument. If the joint is “free” to move without providing substantial support resistance, due to the fulcrum effect of the long elongated shaft passing through the incision, it will result in substantial, unintended swinging of the tool end of the instrument in opposite direction. In a typical laparoscopic or endoscopic procedures where the operating field is small, such instability of the tool will render the tool potentially dangerous and unusable. Unlike the pivotal or ball-and-socket joints that are “free” to move, a bendable member has inherent stiffness which acts to provide necessary support for stabilizing the operator hand's wrist movement, which in turn stabilizes the tool motion. By varying the material and geometry of the bendable member, the appropriate level of stability could be selected. A second important attribute of the bendable member, especially for bending in two degrees of freedom, is its uniformity in bending. Because the bendable member can bend in any direction uniformly, it has no inherent singularity, and as the result, the operator can produce uniform rolling motion of the tool, an important motion for tasks such as suturing, simply by rolling the control handle. On the other hand, if the motion members are comprised of series of pivotal joints, not only may it bind due to singularities, but the rolling of the control handle will result in unwanted side motion of the tool as well, affecting its usability for surgical procedure. A third attribute of the bendable member is its ability to transmit substantial torque axially. By selecting appropriate material and geometry, the bendable member can be constructed to transmit torque axially necessary to perform surgical procedure. On the other hand, the motion member comprised of ball-and-socket joints will not be able to transmit thye necessary torque from the handle to the tool end. A fourth attribute of the bendable member is that it has no sharp bending point, location or pivot and thus this results in an increased life and higher performance. Either pivotal or ball-and-socket joints on the other hand have sharp corners which can increase friction, reduce life and decrease performance of the tool actuation push rod passing through. A fifth attribute of the bendable member is in the reduction of manufacturing cost. The bendable motion member can be injection molded as a single body, thus significantly reducing the cost. Pivotal or ball-and-socket joints are comprised of more part and this results in a higher manufacturing cost. Lastly, a sixth attribute of the bendable member is that it can be easily customized. By varying the stiffness at different points of the bendable member, one can optimize its bending shape for specific applications. While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. For example, the embodiments described herein have primarily used four control cables for providing all direction motion of the motion members. In alternate embodiments fewer or greater numbers of cables may be provided. In a most simplified version only two cables are used to provide single DOF action at the bendable motion member. | <SOH> BACKGROUND OF THE INVENTION <EOH>The present invention relates in general to surgical instruments, and more particularly to manually operated surgical instruments that are intended for use in minimally invasive surgery. Endoscopic and laparoscopic instruments currently available in the market are extremely difficult to learn to operate and use, mainly due to a lack of dexterity in their use. For instance, when using a typical laparoscopic instrument during surgery, the orientation of the tool of the instrument is solely dictated by the locations of the target and the incision, which is often referred to as the fulcrum effect. As a result, common tasks such as suturing, knotting and fine dissection have become challenging to master. Various laparoscopic instruments have been developed over the years to overcome this deficiency, usually by providing an extra -articulation often controlled by a separately disposed knob. However, even with these modifications these instruments still do not provide enough dexterity to allow the surgeon to perform common tasks such as suturing at any arbitrarily selected orientation. Accordingly, an object of the present invention is to provide a laparoscopic or endoscopic surgical instrument that allows the surgeon to manipulate the tool end of the surgical instrument with greater dexterity. | <SOH> SUMMARY OF THE INVENTION <EOH>In accordance with one aspect of the present invention there is provided an endoscopic or laparoscopic instrument that is comprised of a distal tool, a rigid or flexible elongated shaft that supports the distal tool, and a proximal handle or control member, where the tool and the handle are coupled to the respective distal and proximal ends of the elongated shaft via pivoted or bendable motion members. The tool and the tool motion member are coupled to the handle and the handle motion member via cables and a push rod in such a way that the movement of the handle with respect to the elongated shaft in any direction are replicated by the tool at the distal end of the shaft. The magnitude of the tool motion with respect to the handle motion may be scaled depending on the size of the handle motion member with respect to that of the tool motion member. In the present invention one embodiment of the tool motion member is a bending section that is bendable in any arbitrary angle thereby providing two degrees of freedom, whereas in another embodiment, the tool motion member is comprised of the combination of a single plane bendable section and a pivotal joint. In still another embodiment, the motion member is comprised of two pivotal joints orientated orthogonal to each other. In addition to these embodiments where the motion member provides two degrees of freedom, in a situation where less dexterity is needed, the motion member can only be a one degree of freedom member, either pivotal or bendable. In accordance with another aspect of the invention there is provided a manually operated surgical instrument primarily adapted for use in minimally invasive surgery. The instrument comprises an elongated instrument shaft having proximal and distal ends; a proximal turnable member; a control handle coupled to the proximal end of the elongated instrument shaft via the proximal turnable member; a distal turnable member; a surgical tool coupled to the distal end of the elongated instrument shaft via the distal turnable member; and a transmission element that intercouples between the proximal and distal turnable members so that a deflection of the control handle at the proximal turnable member causes a deflection of surgical tool via the distal turnable member. In accordance with still another aspect of the invention there is provided a manually operated surgical instrument primarily adapted for use in minimally invasive surgery. The instrument comprises an elongated instrument shaft having proximal and distal ends; a tool disposed from the distal end of the instrument shaft; and a control handle disposed from the proximal end of the instrument shaft. The tool is coupled to the distal end of the elongated instrument shaft via a first movable member. The control handle is coupled to the proximal end of the elongated instrument shaft via a second movable member. The movement of the control handle with respect to the elongated instrument shaft via the second movable member causes attendant movement of the tool with respect to the elongated instrument shaft via the first movable member. | 20040412 | 20061212 | 20050505 | 69439.0 | 4 | DAWSON, GLENN K | SURGICAL INSTRUMENT | SMALL | 0 | ACCEPTED | 2,004 |
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10,822,146 | ACCEPTED | Electric gas lighter which can be produced with any number of output terminals, and relative production method | An electric gas lighter for generating sparks at one or more burners of a cooking range, and including a transformer having a primary winding, and a secondary winding divided into a number of coils, each having output terminals, and which are wound on respective axially adjacent portions of a substantially cylindrically symmetrical drum forming part of a supporting member made of insulating material and formed in one piece with supports projecting tangentially with respect to the drum and each supporting a respective terminal defined by a blade contact; the coils are connected electrically to one another in series to form one secondary winding, which has been obtained by winding continuously, i.e. without making cuts, an insulated electrically conducting wire onto the drum to form the coils; the wire being wound alternately onto the drum in an opposite direction for each coil; and the winding direction being inverted upon the wire engaging each terminal located axially between two adjacent coils. | 1) An electric gas lighter (1; 1a) for generating sparks at one or more burners of a cooking range, and comprising a transformer having a primary winding (4), and a secondary winding divided into a number of coils (8) and having a predetermined number of output terminals (3); the coils being wound on respective axially adjacent portions of a substantially cylindrically symmetrical, tubular drum (10) forming part of a supporting member (6; 6a) made of electrically insulating material and formed in one piece with supports (12) projecting tangentially with respect to the drum and each supporting a respective said terminal (3); characterized in that the coils (8) are connected electrically to one another in series to form one secondary winding, which has been obtained by continuously winding without making cuts an insulated electrically conducting wire (20) onto the drum (10) to form said coils (8); the wire (20) being wound alternately onto the drum (10) in an opposite direction for each coil (8); and the winding direction of the wire being inverted upon the wire (20) engaging a respective common terminal (3) between two adjacent coils. 2) A gas lighter (1; 1a) as claimed in claim 1, characterized in that each said terminal (3) is defined by a blade contact, e.g. a faston type, for supplying high voltage, in use, to a respective burner; the lighter comprising a number (n) of coils (8) and a number (n+1) of terminals (3), where (n) is any integer greater than 2. 3) A gas lighter (1; 1a) as claimed in claim 2, characterized in that said drum (10) has an odd number (m) of winding seats (11), each for receiving said wire (20) wound in a given direction to form a respective said coil (8), and a number (m+1) of said supports (12) for the terminals (3); in the case of a lighter for lighting an odd number of burners, one of said seats and a respective adjacent support not being engaged by said wire. 4) A gas lighter (1; 1a) as claimed in claim 2, characterized in that said tubular drum (10) has a prismatic tubular member (22) formed in one piece with each said support (12) and for housing a said blade contact (3) fitted to and defining an electric connector with the respective support (12). 5) A gas lighter (1; 1a) as claimed in claim 4, characterized by also comprising an outer casing (2;2a) made of electrically insulating material and housing said supporting member (6), with said wire wound on the drum (10) to form said coils (8) on the outside of the drum, and with said primary winding (4) inserted coaxially inside said tubular drum; said casing (2; 2a) having a number of openings (40) through which said prismatic tubular members (22) formed in one piece with the supports (12) of the terminals (3) are inserted, so that a subunit, defined by the two, primary and secondary, windings with the respective supporting member (6; 6a) and terminals (3), can be preassembled and then fitted automatically inside the casing (2; 2a). 6) A gas lighter (1; 1a) as claimed in claim 5, characterized in that said casing (2; 2a) and said supporting member (6; 6a), with the respective tubular drum (10), respective supports (12), and respective prismatic tubular members (22) for housing the terminals (3), are molded from synthetic plastic material, preferably a polyamide. 7) A gas lighter (1; 1a) as claimed in claim 1, characterized in that, on the outside, at each said coil (8), said tubular drum (10) is formed in one piece with a number of semiannular partitions (41) for dividing each coil (8) into a number of electrically separate sections. 8) A gas lighter (1) as claimed in claim 4, characterized in that said terminals (3), with the relative supports (12) and prismatic tubular housing members (22), are located alternately, in an axial direction, on opposite sides of said casing (2). 9) A gas lighter (la) as claimed in claim 4, characterized in that said terminals (3) are all located side by side along a same first side (200) of said casing (2a); said terminals (3) being carried by respective supports (12), which are formed in one piece with said drum (10) of the insulating said supporting member (6a), project tangentially with respect to the drum (10), and are all arranged side by side along a same side (600) of the drum (10). 10) A gas lighter (1a) as claimed in claim 9, characterized in that said first side (200) of the casing (2a), on which the terminals (3) are all arranged side by side, is selected so as to be opposite a second side (201) of the casing (2a) located on the same side as fastening means (300) integral with the casing (2a) and for clicking the casing (2a) onto an electrically conducting support (C) of an electric household appliance. 11) A method of producing a gas lighter with any number of output terminals, and comprising the steps of: (a) molding from synthetic plastic material a supporting member (6) comprising a tubular drum (10) and a number of supports (12) for respective electric terminals (3); (b) assembling a predetermined number of terminals to the supports, possibly leaving one support with no terminal; (c) assembling the supporting member (6), by means of said tubular drum, to a rotary spindle (50); (d) securing an insulated electrically conducting wire (20) to a first terminal (3) at a first end of the supporting member, and winding said wire onto the tubular drum (10) to form a first coil (8) by rotating the spindle in a given first direction; (e) stopping the spindle (50), securing the wire, without cutting it, to a second terminal (3) adjacent to the coil just formed, and winding said wire onto the tubular drum to form a second coil (8), axially adjacent to the first, by rotating the spindle in a given second direction opposite the first; (f) repeating step (e) n times to form on the tubular drum a given number of coils (8) all connected electrically in series to one another, and with the terminals interposed between common adjacent coils; (g) assembling inside the tubular drum a core (5) made of ferrite and having an electric winding (4), to form an assembly constituting a transformer; and (h) fitting said assembly inside a casing (2), so that said terminals pass through and project from the casing. | The present invention relates to an electric gas lighter which may be used in a cooking range of a gas cooker for generating sparks at one or more burners on the range. BACKGROUND OF THE INVENTION Currently marketed lighters all have an even number of output terminals, each for supplying high voltage to a spark plug for lighting a burner on a cooking range. In the case of a cooking range with an odd number of burners, therefore, a lighter with the nearest number of even terminals must be used, and the extra terminal must be earthed by an earth wire to neutralize its action without impairing operation of the lighter. This is due to known lighters comprising as the main component a transformer, the secondary winding of which is defined by a number of electrically separate coils, each supplying voltage at the opposite ends to two respective terminals. When assembling the cooking range, an additional earth wire (in addition to the one prescribed by regulations) must therefore be used, thus increasing assembly cost, time, and difficulty (in view of the normally confined space involved) . A certain amount of energy is also wasted by being earthed by a wire or various connections. This continuity between the secondary winding wire and earth may even prove damaging in the event of a loss of insulation between the primary and secondary wires (e.g. as a result of a damaged winding or insulation). Generators with odd numbers of output terminals are also marketed, though, in actual fact, these are identical to the former, except that the extra output terminal is earthed by internal connection to the earth on the printed circuit of the lighter, or to the earth contact on the casing. The problem of energy waste therefore remains unsolved, and the advantage in terms of assembly is normally achieved at the expense of higher production cost. SUMMARY OF THE INVENTION It is an object of the present invention to provide a gas lighter designed to eliminate the aforementioned drawbacks, and which, in particular, is compact, is cheap and easy to produce, and can be produced, using the same technology, with an odd or even number of output terminals, thus eliminating the need for an additional earth wire in the case of cooking ranges with an odd number of burners. At the same time, it is also an object of the invention to provide a gas lighter designed to eliminate the drawbacks associated with known gas lighters and relating to possible spark generation between the output terminals, or rather the wires connected to the output terminals, and the cooking range. According to the present invention, there is provided an electric gas lighter as claimed in claim 1. More specifically, as opposed to being separate, the coils defining the secondary winding of the transformer are connected electrically in series to form one secondary winding, which is obtained by continuously winding, without making cuts, an insulated electrically conducting wire onto a drum of an insulating supporting member to form said coils; the wire being wound alternately onto the drum in an opposite direction for each coil; and the winding direction of the wire being inverted upon the wire engaging a respective common terminal placed between two adjacent coils. An even number of coils therefore always has an odd number of output terminals, and, to form an even number of output terminals, the lighter need simply be made with an odd number of coils, i.e. one coil more (or less) than the same model having an odd number of terminals. Consequently, not only does the user of the lighter no longer “waste” an output terminal, thus increasing cost, but the maker of the lighter also benefits in terms of product standardization. For example, the drum need simply be made with an odd (m) number of winding seats, so that it can receive a maximum odd number of coils (and therefore an even number of outputs), and, in the case of a lighter for an odd number of burners, one of the seats need simply be left vacant, with no coil, so that the same structure provides for obtaining a lighter for an even or odd number of burners, as required. The present invention also relates to a method of producing such a lighter, as claimed in claim 11. According to a further preferred aspect of the invention, all the high-voltage output terminals of the lighter are arranged side by side along a same first side of a coil casing; the output terminals are carried by respective supports formed in one piece with the drum of said insulating supporting member, projecting tangentially with respect to the drum, and arranged side by side along a same side of the drum; and said first side of the coil casing supporting all the output terminals of the lighter side by side is opposite a second side of the casing located on the same side as click-on fastening means carried integrally by the casing and for clicking the casing onto an electrically conducting support of an electric household appliance, such as a cooking range. BRIEF DESCRIPTION OF THE DRAWINGS A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: FIG. 1 shows a three-quarter top view in perspective of a supporting member made of plastic and constituting a main member of the lighter according to the invention; FIG. 2 shows a three-quarter bottom view in perspective of the FIG. 1 supporting member; FIGS. 3 to 7 show, schematically, successive steps in the manufacture of the lighter according to the invention; FIG. 8 shows, with parts removed for clarity, a smaller-scale, three-quarter top view in perspective of the lighter according to the invention; FIGS. 9 and 10 show a front and longitudinal view respectively of the way in which a conventional lighter is fitted to a cooking range; FIGS. 11 and 12 show the same views as in FIGS. 9 and 10, but of the way in which a variation of the lighter according to the invention is fitted to a cooking range; FIG. 13 shows a three-quarter top view in perspective of a supporting member made of plastic and constituting a main member of the FIG. 11 and 12 lighter, and rotated 90° with respect to the corresponding view of the corresponding main member of the FIG. 8 lighter in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION As shown in the above drawings, an electric gas lighter, indicated as a whole by reference number 1 (FIG. 8), comprises a casing 2 made of electrically insulating material, e.g. molded from synthetic plastic material, and housing a number of known circuit elements (not shown for the sake of simplicity), and a transformer (not shown in FIG. 8) for supplying high voltage to a predetermined number of terminals 3 fitted to the outside of casing 2 and for supplying said high voltage, for example, to respective spark plugs of respective burners of a cooking range, all of which is known and therefore not shown for the sake of simplicity. The transformer of lighter 1 (FIGS. 1 and 2) comprises a primary winding 4 wound about a cylindrical core 5 of ferrite (or other suitable material); and a supporting member 6 also made of electrically insulating material, e.g. of the same material as casing 2 (e.g. molded from polyamide), and which houses winding 4 with the relative ferrite core, and supports on the outside, i.e. in electrically insulated manner, a secondary winding comprising a number of coils 8, of which only two are shown schematically in FIGS. 6 and 7. Terminals 3 are connected electrically, as will be seen, to the secondary winding (not shown as a whole for the sake of simplicity), and are fitted integrally in known manner to supporting member 6. More specifically, supporting member 6 comprises a tubular, substantially cylindrically symmetrical drum 10 for housing core 5 with winding 4; coils 8 are supported on the outside of drum 10, and are wound about respective axially adjacent portions of drum 10 defined by respective winding seats 11 (FIGS. 1 and 2) of substantially known form; and supports 12 project tangentially from and on the outside of drum 10, are formed integrally in one piece with and of the same material as drum 10, and each support a respective terminal 3. According to the main aspect of the invention, coils 8 are connected electrically to one another in series to form one single secondary winding, which is obtained by continuously winding without making cuts a known electrically conducting wire 20 (FIGS. 3-7), having an insulating coating (e.g. of paint), onto drum 10 to form coils 8. Wire 20 is wound alternately onto drum 10 in an opposite direction for each coil 8, and the winding direction of wire 20 is inverted upon wire 20 engaging a common terminal 3 placed between two adjacent coils 8 (FIGS. 5, 6). Each terminal 3 (FIG. 2) is defined by a blade contact, e.g. faston type, for supplying high voltage in known manner to a respective burner. According to the invention, and as explained in detail later on, lighter 1 comprises a number (n) of coils 8, and a number (n+1) of terminals 3, where (n) is any whole number (integer) greater than 2. Drum 10 preferably comprises an odd number (m) of winding seats 11, each for receiving wire 20 wound in a predetermined direction to form a respective coil 8; and a number (m+1) of supports 12 for terminals 3. According to a further aspect of the invention, tubular drum 10 comprises, integral in one piece with each support 12, a prismatic tubular member 22 for housing a respective blade contact (terminal) 3 carried integrally in known manner, e.g. clicked onto, respective support 12, so as to define, with terminal 3, a standard electric connector. In combination with the above characteristic, casing 2 (FIG. 8)—which, as stated, houses supporting member 6 with wire 20 wound about drum 10 to form coils 8 on the outside of drum 10, and with primary winding 4 inserted coaxially inside drum 10—has a number of openings 40 through which prismatic tubular members 22 are inserted. On the outside and at each coil 8, tubular drum 10 (FIG. 2) is preferably formed in one piece with a number of semiannular partitions 41 for dividing each coil 8 in known manner into a number of electrically separate sections. With reference to FIGS. 3-7, lighter 1 according to the invention as described above is produced using a method comprising the steps of: (a) molding casing 2 and supporting member 6 from synthetic plastic material; (b) assembling a predetermined number of terminals 3 (in interference, click-on, or any other manner) to supports 12 and inside members 22, possibly leaving one support 12 with no terminal 3; (c) assembling supporting member 6, by means of tubular drum 10, to a rotary spindle 50; this may also be movable axially to engage/release drum 10 (FIG. 3); or in case of a non-axially-moving rotary spindle is used a loading/unloading spindle (known and not shown for the sake of simplicity) is also used; (d) securing conducting wire 20, e.g. carried in a magazine not shown, to a first terminal 3 at a first end of supporting member 6, e.g. using a known wire handling and tensioning device 52, and then (FIG. 4) winding wire 20 onto tubular drum 10 to form a first coil 8 adjacent to said terminal 3 engaged by wire 20, by rotating the spindle in a given first, e.g. anticlockwise, direction; (e) stopping spindle 50, securing wire 20 (FIG. 5), without cutting it, to a second terminal 3 immediately adjacent to the coil 8 just formed, and winding wire 20 onto tubular drum 10 to form a second coil 8, axially adjacent to and connected electrically in series to the first, by rotating spindle 50 in a given second direction opposite the first, e.g. clockwise (FIG. 6); (f) repeating step (e) n times (depending on the number of seats 11 on member 6) to form on tubular drum 10 a given number of coils 8 all connected electrically in series to one another, and with terminals 3 interposed between common adjacent coils 8; (g) assembling core 5, complete with winding 4, inside tubular drum 10 to form an assembly constituting a transformer; and (h) fitting said assembly inside casing 2, so that terminals 3 pass through and project from casing 2—in the example shown, by inserting members 22 inside openings 40. Wire 20 may be connected to terminals 3, as shown schematically, by simply inserting wire 20 inside holes 60 (FIG. 2) in terminals 3, and soldering later. A subunit, defined by said assembly comprising the two, primary and secondary, windings of the transformer with supporting member 6 and terminals 3, may be preassembled as described above, and then assembled automatically inside casing 2, using members 22 and openings 40 as assembly guides. The same lighter 1 with an odd number m of seats 11 may therefore be used to light both an even number m+1 of burners (equal to the number of terminals 3 when all the seats are used), and an odd number m of burners by simply leaving one of seats 11 and a respective adjacent support 12 free of wire 20, i.e. by forming one coil 8 less than the number permitted by the structure of supporting member 6, thus enabling considerable scale economy in the manufacture of the molded plastic parts. By way of comparison with the solution according to the invention, FIGS. 9 and 10 show a conventional lighter, indicated as a whole by A, comprising a casing I, from which project prismatic members 22 housing respective terminals 3. Lighter A is shown fitted for use to a known cooking range C, with terminals 3 (FIG. 9) engaged by respective high-voltage output wires T connected in known manner (not shown) to respective electrodes close to the burners of cooking range C to be lit. Terminals 3 along the centreline of casing I are obviously arranged in pairs in the same axial positions, project from opposite sides of casing I, and are therefore stacked on cooking range C. Since, for electric insulation purposes, a given distance “d” must be maintained between terminals 3, this distance, in the case of lighter A, is measured vertically, i.e. perpendicular to cooking range C. Conversely, in the case of lighter 1 described, by virtue of the way in which coils 8 are wound, terminals 3 (with relative supports 12 and tubular members 22) are never paired in the same axial position on opposite sides of the casing, but, as shown clearly in FIGS. 1-8, are located alternately, in an axial direction, on opposite sides of casing 2. Consequently, distance “d” is measured diagonally (FIG. 8), so that casing 2 can be made more compact vertically than casing I, which is a fairly desirable market characteristic. According to a no less important aspect of the invention, the vertical size of the lighter casing can be further reduced. FIGS. 11 to 13, in fact, show a preferred variation la of lighter 1 according to the invention, in which details similar to or identical with those already described are indicated for the sake of simplicity using the same reference numbers. Lighter 1a has all the high-voltage output terminals 3 arranged side by side along a same first side 200 of a casing 2a housing coils 8; output terminals 3 are carried by respective supports 12 formed in one piece with the drum 10 of an insulating supporting member 6a; and supporting member 6a is substantially identical with supporting member 6 described above, except that supports 12 are formed in one piece with it so as to project tangentially with respect to drum 10, and are all located side by side along a same side 600 of drum 10. The first side 200 of casing 2a of coils 8, on which output terminals 3 of lighter 1a are all arranged side by side, is selected so as to be opposite a second side 201 of casing 2a, located on the same side as known means 300 integral with casing 2a and defined, for example, by elastic teeth for clicking casing 2a onto an electrically conducting support of an electric household appliance—in this case, onto cooking range C. Consequently, terminals 3 with relative supports 12 and prismatic tubular members 22 are all located, in use, on the opposite side to cooking range C (FIGS. 11, 12). This provides for further reducing the vertical size of the lighter according to the invention, and, above all, prevents some of the wires T from having to be fitted adjacent to cooking range C, as in known lighters (see wire T1 in FIG. 9). This not only greatly simplifies the wiring of lighter 1a, but, above all, safeguards against sparks being generated between wires T and cooking range C, on account of wires T all being located at least distance “d” from cooking range C. | <SOH> BACKGROUND OF THE INVENTION <EOH>Currently marketed lighters all have an even number of output terminals, each for supplying high voltage to a spark plug for lighting a burner on a cooking range. In the case of a cooking range with an odd number of burners, therefore, a lighter with the nearest number of even terminals must be used, and the extra terminal must be earthed by an earth wire to neutralize its action without impairing operation of the lighter. This is due to known lighters comprising as the main component a transformer, the secondary winding of which is defined by a number of electrically separate coils, each supplying voltage at the opposite ends to two respective terminals. When assembling the cooking range, an additional earth wire (in addition to the one prescribed by regulations) must therefore be used, thus increasing assembly cost, time, and difficulty (in view of the normally confined space involved) . A certain amount of energy is also wasted by being earthed by a wire or various connections. This continuity between the secondary winding wire and earth may even prove damaging in the event of a loss of insulation between the primary and secondary wires (e.g. as a result of a damaged winding or insulation). Generators with odd numbers of output terminals are also marketed, though, in actual fact, these are identical to the former, except that the extra output terminal is earthed by internal connection to the earth on the printed circuit of the lighter, or to the earth contact on the casing. The problem of energy waste therefore remains unsolved, and the advantage in terms of assembly is normally achieved at the expense of higher production cost. | <SOH> SUMMARY OF THE INVENTION <EOH>It is an object of the present invention to provide a gas lighter designed to eliminate the aforementioned drawbacks, and which, in particular, is compact, is cheap and easy to produce, and can be produced, using the same technology, with an odd or even number of output terminals, thus eliminating the need for an additional earth wire in the case of cooking ranges with an odd number of burners. At the same time, it is also an object of the invention to provide a gas lighter designed to eliminate the drawbacks associated with known gas lighters and relating to possible spark generation between the output terminals, or rather the wires connected to the output terminals, and the cooking range. According to the present invention, there is provided an electric gas lighter as claimed in claim 1 . More specifically, as opposed to being separate, the coils defining the secondary winding of the transformer are connected electrically in series to form one secondary winding, which is obtained by continuously winding, without making cuts, an insulated electrically conducting wire onto a drum of an insulating supporting member to form said coils; the wire being wound alternately onto the drum in an opposite direction for each coil; and the winding direction of the wire being inverted upon the wire engaging a respective common terminal placed between two adjacent coils. An even number of coils therefore always has an odd number of output terminals, and, to form an even number of output terminals, the lighter need simply be made with an odd number of coils, i.e. one coil more (or less) than the same model having an odd number of terminals. Consequently, not only does the user of the lighter no longer “waste” an output terminal, thus increasing cost, but the maker of the lighter also benefits in terms of product standardization. For example, the drum need simply be made with an odd (m) number of winding seats, so that it can receive a maximum odd number of coils (and therefore an even number of outputs), and, in the case of a lighter for an odd number of burners, one of the seats need simply be left vacant, with no coil, so that the same structure provides for obtaining a lighter for an even or odd number of burners, as required. The present invention also relates to a method of producing such a lighter, as claimed in claim 11 . According to a further preferred aspect of the invention, all the high-voltage output terminals of the lighter are arranged side by side along a same first side of a coil casing; the output terminals are carried by respective supports formed in one piece with the drum of said insulating supporting member, projecting tangentially with respect to the drum, and arranged side by side along a same side of the drum; and said first side of the coil casing supporting all the output terminals of the lighter side by side is opposite a second side of the casing located on the same side as click-on fastening means carried integrally by the casing and for clicking the casing onto an electrically conducting support of an electric household appliance, such as a cooking range. | 20040412 | 20060829 | 20050310 | 70589.0 | 0 | MAI, ANH T | ELECTRIC GAS LIGHTER WHICH CAN BE PRODUCED WITH ANY NUMBER OF OUTPUT TERMINALS, AND RELATIVE PRODUCTION METHOD | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,822,233 | ACCEPTED | Device and method for monitoring movement within a home | A device and method for monitoring whether a resident is away from home or inactive within the home. A sensor, which includes a transmitter, a processor, a timer, and a detector, watches for motion to occur within a home. Upon sensing motion, the sensor sends a first signal indicative of the motion if the timer is not currently running and waits for the motion to end. If the timer already is running, the timer is restarted at zero. Upon expiration of a predetermined timing period, the sensor transmits a second signal indicative of inactivity. By comparing the timing of the second signal and the predetermined timing period, with a third signal sent by an exterior door sensor, a determination can be made whether the resident has left the home or is inactive within the home. | 1. A wireless motion sensor for determining when motion ceases, comprising: a detector for detecting activity; a transmitter for transmitting a first signal indicative of a first detection of activity; a processor; and a timer which begins running upon a first detection of activity; wherein upon the timer running to a set time period without detection of any subsequent activity after the first detection of activity, the transmitter transmits a second signal indicative of inactivity. 2. The wireless motion sensor of claim 1, wherein the transmitter is adapted for wirelessly transmitting the first and second signals. 3. The wireless motion sensor of claim 1, wherein the detector comprises a signal processor and a sensing portion. 4. The wireless motion sensor of claim 3, wherein the sensing portion comprises at least one sensing mechanism utilizing a sensing technique from the group consisting of passive infrared, ultrasound, microwave, radar, infrared, and any combinations thereof. 5. The wireless motion sensor of claim 3, wherein the sensing portion includes a passive infrared detecting mechanism. 6. The wireless motion sensor of claim 1, wherein the set time period is no greater than five minutes. 7. The wireless motion sensor of claim 1, wherein the sensor is configured to detect activity in the vicinity of one or more from the group consisting of interior doors, cabinet drawers, appliances, beds, couches or chairs. 8. The wireless motion sensor of claim 7, wherein the sensor comprises a pad for detecting activity on one or more from the group consisting of beds, couches or chairs. 9. A wireless motion sensor for determining when motion ceases, comprising: a detector for detecting activity, wherein the detector comprises a signal processor and a sensing portion; a transmitter for transmitting a first signal indicative of a first detection of activity, wherein the transmitter is adapted for wirelessly transmitting the first and second signals; a processor; and a timer which begins running upon a first detection of activity; wherein upon the timer running to a set time period without detection of any subsequent activity after the first detection of activity, the transmitter transmits a second signal indicative of inactivity. 10. The wireless motion sensor of claim 9, wherein the sensing portion comprises at least one sensing mechanism utilizing a sensing technique from the group consisting of passive infrared, ultrasound, microwave, radar, infrared, and any combinations thereof. 11. The wireless motion sensor of claim 9, wherein the sensing portion includes a passive infrared detecting mechanism. 12. The wireless motion sensor of claim 9, wherein the set time period is no greater than five minutes. 13. The wireless motion sensor of claim 9, wherein the sensor is configured to detect activity in the vicinity of one or more from the group consisting of interior doors, cabinet drawers, appliances, beds, couches or chairs. 14. The wireless motion sensor of claim 13, wherein the sensor comprises a pad for detecting activity on one or more from the group consisting of beds, couches or chairs. 15. A method for determining inactivity within a home, comprising the steps of: watching for an indication of motion; sensing motion; wirelessly sending a first signal indicative of the motion; starting a timer for a set time period; and upon expiration of the set time period without sensing any further motion, wirelessly sending a second signal indicative of inactivity. 16. The method of claim 15, wherein the sending of the first and second signals is accomplished with a transmitter. 17. The method of claim 15, wherein the watching is accomplished with a sensor utilizing a sensing technique from the group consisting of passive infra-red, ultrasound, microwave, radar, infra-red, and any combinations thereof. 18. The method of claim 15, wherein the set time period is no greater than five minutes. 19. A method for determining inactivity within a home, comprising the steps of: watching for an indication of motion; sensing motion; wirelessly sending a first signal indicative of the motion via a transmitter; starting a timer for a set time period no greater than five minutes; and upon expiration of the set time period without sensing any further motion, wirelessly sending a second signal indicative of inactivity. 20. The method of claim 19, wherein the watching for the indication of motion is accomplished with a sensor utilizing a sensing technique from the group consisting of passive infra-red, ultrasound, microwave, radar, infra-red, and any combinations thereof. 21. The method of claim 19, further comprising determining a time actual inactivity occurs within the home based upon the time the second signal is sent and the length of the set time period. | BACKGROUND The invention relates generally to a device and method for monitoring activity within a home. More particularly, the invention relates to a device and method for determining, through the monitoring of in-home movement, whether a resident of a home is at home or has left the home. With medical advancements and increased attention to proper nutrition and sufficient exercise, the populace in the western civilization is living longer. For example, the number of elderly persons residing in the United States is increasing, and with the advancing age of the baby boomer generation, the number of elderly persons in the United States will increase significantly over the next several decades. Additionally, increased awareness and understanding of various mental and physical disabilities has led to an increase in the number of persons having diminished mental and/or physical faculties living independently. With the increase in elderly and disabled persons living independently has come anxiety that these elderly and disabled persons are safe and secure in their own residences. There is increased anxiety by the elderly and disabled living alone that they may become injured or incapacitated and be unable to summon assistance. That anxiety is often shared by loved ones living at a distance from the elderly and/or disabled living independently. Currently, the anxiety felt by the elderly and disabled living alone, as well as the anxiety felt by their loved ones, is addressed through several avenues. One way to ease anxiety is through frequent visits to the home by a caregiver. Such visits can be intrusive, time consuming, and often inconvenient and not appreciated. Another way is for the elderly or disabled person to move out of the home and move into a facility better able to monitor his health. This, however, strips the person of his independence, is costly and is often unwelcome. Another way is through technological assistance or monitoring of the person in the home. Such technological systems that assist persons in their home include Personal Emergency Response Systems. In these systems the elderly or disabled individual wears a watch, pendant or other like device and presses a button in the event of an emergency, such as a fall. The depressed button enables an alarm signal. A central monitoring facility provides assistance by responding to the alarm signal and calls the individual to identify the problem. The facility calls a predetermined list of contacts, such as relatives, neighbors or emergency services, as required by the context of the situation. While a valuable service, these systems only identify problems that occur when the individual is able to press the emergency button. One disadvantage experienced with some known in-home monitoring systems is the inability to accurately detect whether a resident within a monitored home has been unusually inactive or is instead away from the home. These known in-home monitoring systems provide the resident with one or more button that can be pressed to indicate whether the resident is home or is away. The resident's responsibility to indicate whether he is in the house or away often goes unfulfilled, leading to a high false alert rate and low sensitivity for such known systems. Thus, there remains a need for a device and method for monitoring movement within a home. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a motion sensor constructed in accordance with an exemplary embodiment of the invention. FIG. 2 is a schematic view of a system using the motion sensor of FIG. 1. FIG. 3 is a flow diagram of the process steps taken by the motion sensor of FIG. 1 in ascertaining whether a resident is at home or away. FIG. 4 is a flow diagram of the process steps taken by a conventional motion sensor in ascertaining whether a resident is at home or away. SUMMARY The invention is directed to a system, device and method for ascertaining whether a resident of a monitored home is at home or has left the home. One aspect of the invention is a wireless motion sensor for determining when motion ceases. The motion sensor includes a detector for detecting activity, a transmitter for transmitting a first signal indicative of a first detection of activity, a processor, and a timer that begins running upon a first detection of activity. Upon the timer running to a set time period without detection of any subsequent activity after the first detection of activity, the transmitter transmits a second signal indicative of inactivity. Another aspect of the invention is a wireless motion sensor for determining when motion ceases. The motion sensor includes a detector for detecting activity, wherein the detector comprises a signal processor and a sensing portion, a transmitter for transmitting a first signal indicative of a first detection of activity, wherein the transmitter is adapted for wirelessly transmitting the first and second signals, a processor, and a timer which begins running upon a first detection of activity. Upon the timer running to a set time period without detection of any subsequent activity after the first detection of activity, the transmitter transmits a second signal indicative of inactivity. Another aspect of the invention is a method for determining inactivity within a home. The method includes the steps of watching for an indication of motion, sensing motion, wirelessly sending a first signal indicative of the motion, starting a timer for a predetermined period of time, and upon expiration of the predetermined period of time without sensing any further motion, wirelessly sending a second signal indicative of inactivity. Another aspect of the invention is a method for determining inactivity within a home. The method includes the steps of watching for an indication of motion, sensing motion, wirelessly sending a first signal indicative of the motion via a transmitter, and starting a timer for a set time period no greater than five minutes. Upon expiration of the set time period without sensing any further motion, a second signal indicative of inactivity is wirelessly sent. These and other advantages and features will be more readily understood from the following detailed description of preferred embodiments of the invention that is provided in connection with the accompanying drawings. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings, where like numerals relate to like features, there is shown in FIG. 1 a wireless motion sensor 10 constructed in accordance with an exemplary embodiment of the invention. The motion sensor 10 includes a transmitter 12, a processor 14, and a timer 16. The processor 14 includes logic portions of the sensor 10. The motion sensor 10 further includes a detector section 18. The detector section 18 includes a hardware portion 20 and a signal processor 22. The hardware portion 20 includes a sensing portion that detects motion. The hardware portion 20 serves to pass an amplified and filtered version of the output of the sensing portion to the signal processor 22. The signal processor 22 includes necessary logic to determine if the signal coming from the hardware portion 20 constitutes an alarm. The hardware portion 20 preferably includes a passive infrared motion detector mechanism. Alternatively, the hardware portion may include ultrasonic, microwave, radar, or infrared motion detectors, or any combinations of these, such as, for example, infrared with microwave or infrared with radar. The signal processor 22 takes signals from the hardware portion 20 and determines what is motion. With reference to FIG. 2, an activity monitoring system 100, including the motion sensor 10, is illustrated. The activity monitoring system 100 includes, in addition to one or more motion sensors 10, one or more exterior door sensors 32, a communication relay panel 36, and a remote monitoring center 42. The activity monitoring system 100 lacks mechanisms to intervene in the home 30 or any subsystems (appliances, water, lights, etc.) of the home 30. Intervention in the home 30, if any, may arrive through a communication with the resident of the home 30 from outside the home, such as via a telephone call or a visit from a caregiver or other suitable person, such as an emergency response professional. The motion sensors 10 may include sensors positioned about the home 30 to detect activity of the resident, or may be inside door sensors, cabinet sensors, kitchen and appliance sensors, and any other sensors suitable for collecting and communicating data regarding activities on-going in the home 30. Further, the motion sensors 10 may take any suitable form, such as, for example, a module attached to a wall, interior door, appliance, or cabinet drawer. Alternatively, the motion sensors 10 may take the form of a pad placed upon a bed, couch or chair to monitor a resident's use of same. The exterior door sensors 32 may be one or more sensors positioned on doors providing ingress and egress from the home 30. Preferably, the sensors 10, 32 are wireless sensors capable of wirelessly communicating signals 34, which include data collected, to the communications relay panel 36. It should be appreciated, however, that the sensors 10, 32 instead may be sensors hardwired to the communications relay panel 36. The communications relay panel 36 communicates the sensor data collected from the sensors 10, 32 by sending a data signal 38 containing the sensor data to the remote monitoring center 42 by way of a suitable wired or wireless communications platform 40, such as, for example, wired telephone, wireless telephone, two-way walkie-talkie, pager, cable, the Internet browser, or any other wireless communication platform. Depending upon the communication platform 40 chosen, the data signals 38 may be sent in near real-time or may be sent at discrete, irregular intervals. By near real-time is meant within the range of almost instantaneously to up to three minutes. For example, data signals 38 may be sent in near real-time via wireless telephone, two-way walkie-talkie, pager, cable, the Internet browser or any other wireless communication platform. For a wired telephone communication platform, the data signals 38 are buffered and transmitted at differing intervals. The monitoring center 42, which is remote from the home 30, includes a database 46, a programmable event detector 48, and a continuous status report generator 50. The database 46 serves as a collection vessel for the sensor data communicated via the signals 38. A search mechanism 44 is used for searching the database 46. Upon a request from the caregiver for a status report, the sensor data is forwarded from the database 46 to the continuous status report generator 50. The status report generator 50 communicates a near real-time status signal to a personal computer of the caregiver. By near real-time is meant anywhere in the range of almost instantaneously to up to three minutes. For example, for a two-way page communication platform 40, the amount of time required for the communication can be between two and three minutes. The status report generator 50 may be programmed to update the report for each home 30 at a certain interval, such as, for example, every ten minutes. The status signal includes a report generated by the continuous status report generator 50. The format and substance of the report are dependent upon the request of the caregiver and can be modified at the request of the caregiver. It should be appreciated that the signal can instead be communicated via a personal digital assistant (PDA), a pager, a facsimile machine, cable, or a telephone or voice-mail account instead of via the personal computer. The caregiver 38 can also select certain activities that, if they occur in the home 30, would be considered an event. An event, in general, would include an activity or any important transition occurrence, such as a state transition (the change from one state to another, such as, for example, from active to quiet), of which a caregiver would want to be apprised. For example, use of an exterior door may be considered an important activity or state transition occurrence. The caregiver communicates the parameters of what constitutes an event to the remote monitoring center 42 via a signal. While the caregiver does not determine whether an event has occurred, the caregiver can select from a set of predefined activities which constitutes an event. Further, the caregiver sets the parameters to configure the events to match the normal activity of the resident in the home 30. For example, the caregiver does not define what constitutes, for example, “wake up”, but the caregiver can define when “wake up” would be considered late. The sensor data is stored and processed at the monitoring center 42. If the data indicates the occurrence of an event, a signal is sent to the caregiver via any suitable communication medium, such as, for example, wired or wireless telephone, PDA, pager, facsimile, cable, two-way walkie-talkie, e-mail, or other Internet-supported communication media, such as, for example, through a pop-up announcement format. The caregiver is then provided the opportunity to open a communication pathway with the person residing in the home 30. The communication pathway may be through a wired or wireless telephone line, the Internet browser (i.e., e-mail or other Internet-sponsored communication tool), cable, PDA, pager, or personal, such as a visit by the caregiver or another suitable person. The sensors 10, 32 can be positioned in various locations throughout the home 30. The sensors 10, 32 may be categorized by types, for example, as motion, exterior door (sensor 32), food, or automobile sensors. It should be appreciated that the number of sensors 10, 32 used may depend upon the layout of the home 30, as well as other factors. Next, with specific reference to FIG. 4, will be described a conventional process for determining when motion is occurring in a room monitored by a motion sensor. At Step 160, the motion sensor watches for any detectable sign of motion or activity. When motion is detected, an “Open” signal is transmitted at Step 162. At Step 164, the motion sensor continues to watch until no further motion has been seen for about three to four seconds. At this juncture, the sensor may optionally transmit a “Close” at Step 166. The sensor, regardless of whether Step 166 occurs, then goes to sleep, or temporarily becomes inactive, for about three minutes at Step 168. By going to sleep at Step 168, the use of conventional motion sensors may lead to anomalous results. For example, a resident may open an exterior door, such as a door off of the kitchen to put out the garbage, put out the garbage and close the door and move to the bedroom within a time span of less than three or four minutes. By opening the exterior door, the conventional motion sensor has reported an open at Step 162, and then gone into the sleep mode at Step 168. During that sleep mode, the resident has ample time to close the exterior door, go to his bedroom and go to bed. Under such a scenario, the system will sense no further movement within the home, thus leading the system to conclude that the resident has left the home. The motion sensors 10 within the activity monitoring system 100 utilize a different logic scheme to address the disadvantages of the approximately four-minute long sleep period experienced by conventional motion sensors. With reference to FIG. 3, next will be described the flow logic of the motion sensors 10. At Step 60, the detector 18 of the motion sensor 10 watches for any detectable sign of motion or activity. While the motion sensor 10 watches for activity, the timer 16 (FIG. 1) is running. If the motion sensor 10 sees motion at Step 66, the processor 14 initiates a query 68 as to whether the timer 16 is running. Upon seeing motion for the first time, the timer 16 will not be running, and thus, at Step 70 an open is reported via a first signal from the transmitter 12. By open is meant that the detector 18 has detected activity. The detector 18 of the motion sensor 10 will continue to watch; however, no further motion will be reported, as continuous reporting takes up battery power. If the timer 16 is running, at Step 72 the timer 16 is restarted at zero. If the timer 16 is not running and after the open has been reported, the timer 16 is started at zero at Step 72. After Step 72, the logic returns to Step 60 and the motion sensor 10 watches for renewed motion. Typically, motion occurs intermittently, and so if the detector 18 sees motion again at Step 66 before the timer expires at Step 62, the answer to the query at Step 68 will be yes, and that will be followed by a restarting of the timer 16 at zero at Step 72. Upon expiration of the timer 16, which was started or restarted at Step 72 and which occurs after N minutes at Step 62, at Step 64 a close is reported via a second signal from the transmitter 12. By close is meant that no activity has been detected within the N time period. Preferably, the N time period for which the timer 16 runs before expiring is about four minutes. It should be appreciated, however, that any amount of time should be suitable as long as the N time period is known. Higher values of N will extend battery life. After reporting a close at Step 64, the logic returns to Step 60. The open and the close are both reported by transmitting the first and second signals to a personal emergency response system or other external system (“PERS”) 52 (FIG. 2). The PERS 52 knows the length of time the timer 16 runs, and thus a simple subtraction of the length of time the timer 16 has run from the time the close was reported at Step 64 will provide an actual time that activity ceased within the home 30. By comparing the actual time that activity has ceased in the home 30 with data from the external door sensors 32, an accurate determination as to whether inactivity within the home 30 is due to the resident being away from the home 30 can be made. Alternatively, whether inactivity within the home 30 is due to the resident ceasing to move also can be more accurately determined. While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims. | <SOH> BACKGROUND <EOH>The invention relates generally to a device and method for monitoring activity within a home. More particularly, the invention relates to a device and method for determining, through the monitoring of in-home movement, whether a resident of a home is at home or has left the home. With medical advancements and increased attention to proper nutrition and sufficient exercise, the populace in the western civilization is living longer. For example, the number of elderly persons residing in the United States is increasing, and with the advancing age of the baby boomer generation, the number of elderly persons in the United States will increase significantly over the next several decades. Additionally, increased awareness and understanding of various mental and physical disabilities has led to an increase in the number of persons having diminished mental and/or physical faculties living independently. With the increase in elderly and disabled persons living independently has come anxiety that these elderly and disabled persons are safe and secure in their own residences. There is increased anxiety by the elderly and disabled living alone that they may become injured or incapacitated and be unable to summon assistance. That anxiety is often shared by loved ones living at a distance from the elderly and/or disabled living independently. Currently, the anxiety felt by the elderly and disabled living alone, as well as the anxiety felt by their loved ones, is addressed through several avenues. One way to ease anxiety is through frequent visits to the home by a caregiver. Such visits can be intrusive, time consuming, and often inconvenient and not appreciated. Another way is for the elderly or disabled person to move out of the home and move into a facility better able to monitor his health. This, however, strips the person of his independence, is costly and is often unwelcome. Another way is through technological assistance or monitoring of the person in the home. Such technological systems that assist persons in their home include Personal Emergency Response Systems. In these systems the elderly or disabled individual wears a watch, pendant or other like device and presses a button in the event of an emergency, such as a fall. The depressed button enables an alarm signal. A central monitoring facility provides assistance by responding to the alarm signal and calls the individual to identify the problem. The facility calls a predetermined list of contacts, such as relatives, neighbors or emergency services, as required by the context of the situation. While a valuable service, these systems only identify problems that occur when the individual is able to press the emergency button. One disadvantage experienced with some known in-home monitoring systems is the inability to accurately detect whether a resident within a monitored home has been unusually inactive or is instead away from the home. These known in-home monitoring systems provide the resident with one or more button that can be pressed to indicate whether the resident is home or is away. The resident's responsibility to indicate whether he is in the house or away often goes unfulfilled, leading to a high false alert rate and low sensitivity for such known systems. Thus, there remains a need for a device and method for monitoring movement within a home. | <SOH> SUMMARY <EOH>The invention is directed to a system, device and method for ascertaining whether a resident of a monitored home is at home or has left the home. One aspect of the invention is a wireless motion sensor for determining when motion ceases. The motion sensor includes a detector for detecting activity, a transmitter for transmitting a first signal indicative of a first detection of activity, a processor, and a timer that begins running upon a first detection of activity. Upon the timer running to a set time period without detection of any subsequent activity after the first detection of activity, the transmitter transmits a second signal indicative of inactivity. Another aspect of the invention is a wireless motion sensor for determining when motion ceases. The motion sensor includes a detector for detecting activity, wherein the detector comprises a signal processor and a sensing portion, a transmitter for transmitting a first signal indicative of a first detection of activity, wherein the transmitter is adapted for wirelessly transmitting the first and second signals, a processor, and a timer which begins running upon a first detection of activity. Upon the timer running to a set time period without detection of any subsequent activity after the first detection of activity, the transmitter transmits a second signal indicative of inactivity. Another aspect of the invention is a method for determining inactivity within a home. The method includes the steps of watching for an indication of motion, sensing motion, wirelessly sending a first signal indicative of the motion, starting a timer for a predetermined period of time, and upon expiration of the predetermined period of time without sensing any further motion, wirelessly sending a second signal indicative of inactivity. Another aspect of the invention is a method for determining inactivity within a home. The method includes the steps of watching for an indication of motion, sensing motion, wirelessly sending a first signal indicative of the motion via a transmitter, and starting a timer for a set time period no greater than five minutes. Upon expiration of the set time period without sensing any further motion, a second signal indicative of inactivity is wirelessly sent. These and other advantages and features will be more readily understood from the following detailed description of preferred embodiments of the invention that is provided in connection with the accompanying drawings. | 20040409 | 20070710 | 20051027 | 71028.0 | 0 | TANG, SON M | DEVICE AND METHOD FOR MONITORING MOVEMENT WITHIN A HOME | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,822,481 | ACCEPTED | Orthopedic pet cushion | An orthopedic cushion for a support humans and animals, particularly domestic pets, includes a plurality of layers including a padding layer of slow recovery visco-elastic foam providing the orthopedic advantages of reducing pressure points and facilitating blood flow, a supporting padding layer of material which supports the slow recovery visco-elastic foam while providing additional loft and cushioning, a protective liner of a flexible waterproof yet breathable material protecting the padding from liquids of all nature, and a washable fabric cover. The pet bed of the present invention is orthopedic, washable, stain-resistant, hypoallergenic, and comfortable. | 1. A cushion for domestic pets comprising: (a) A padding layer of slow recovery visco-elastic foam; (b) a supporting padding layer of a stabilizing material which supports the visco-elastic foam and provides additional cushioning, adjacent to said cushion of slow recovery visco-elastic foam; (c) a protective liner of a waterproof, breathable, flexible material, enclosing both the said padding material of visco-elastic foam and said supporting padding material; (d) a washable fabric cover totally enclosing said padding material of slow recovery visco-elastic foam, said supporting padding material, and said protective liner. 2. The cushion as recited in claim 1, wherein the supporting padding layer is comprised of a textile-based material. 3. The cushion as recited in claim 1, wherein the supporting padding layer is comprised of a foam material. 4. The cushion as recited in claim 1, wherein the supporting padding layer is comprised of a rubber material. 5. The cushion as recited in claim 1, wherein said waterproof, breathable, and flexible protective liner material comprises a hydrophilic laminate. 6. The cushion as recited in claim 1, wherein said waterproof, breathable, and flexible protective liner material comprises a hydrophilic coating. 7. The cushion as recited in claim 1, wherein said waterproof, breathable, and flexible protective liner material comprises a microporous laminate. 8. The cushion as recited in claim 1, wherein said waterproof, breathable, and flexible protective liner material comprises a microporous coating. 9. The cushion as recited in claim 1, wherein said waterproof, breathable, and flexible protective liner material comprises a bi-component laminate. 10. The cushion as recited in claim 1, wherein said waterproof, breathable, and flexible protective liner material comprises a bi-component coating. 11. The cushion as recited in claim 1, wherein said waterproof, breathable, and flexible protective liner material comprises a material fabricated from a microfiber of a sufficiently close weave to be waterproof and breathable. 12. The cushion as recited in claim 1, wherein said waterproof, breathable, and flexible protective liner is comprised of a material fabricated with a monolithic membrane. 13. The cushion as recited in claim 1, wherein said waterproof, breathable, and flexible protective liner material is naturally oleophobic, anti-dust mite, anti-odor, anti-bacterial, anti-stain, and anti-static. 14. The cushion as recited in claim 1, wherein said outer fabric cover has a releasable closure so that said fabric cover may be removed from the said padding of slow recovery visco-elastic foam, said padding of stabilizing support material, and said protective liner, for washing. 15. The cushion as recited in claim 1, wherein said out fabric cover is comprised of a top surface, a bottom surface, and peripheral side walls disposed between said top and bottom surfaces. 16. The cushion as recited in claim 1, wherein said waterproof, breathable, and flexible protective liner is sealed closed around said padding layer of slow-recovery visco-elastic foam and said supporting padding layer in such a close-fitting and tight manner that the protective liner does not allow for the inner padding layers, of said slow recovery visco-elastic foam and said supporting stabilizing material to shift or move about within the said protective liner. 17. The cushion as recited in claim 1 wherein said cushion has numerous overall geometric shape possibilities, as in having a generally square shape, as in having a generally round shape, as in having a generally rectangular shape, as in having a generally semi-circle, as in having a generally triangular, or as in having a generally pie-shaped shape. 18. The cushion as recited in claim 1, wherein said cushion may be used by a domestic pet or human. 19. An orthopedic cushion for a pet comprising: (a) A padding layer of slow recovery visco-elastic foam; (b) A supporting padding layer of a stabilizing material which supports the visco-elastic foam and provides additional cushioning, adjacent to said cushion of slow recovery visco-elastic foam; (c) a protective liner of waterproof, breathable, and flexible moisture-vapor-transmission (MVT) membrane material enclosing both said padding materials of slow recovery visco-elastic foam and said supporting padding material, and having capability to prevent liquid from reaching said slow recovery visco-elastic foam and said supporting padding layers; (d) A washable, removable fabric cover, with a releasable closure, totally enclosing said padding material layers of slow recovery visco-elastic foam and said supporting padding material, and said protective liner. 20. The orthopedic pet cushion as recited in claim 19, wherein said protective liner of breathable, waterproof, MVT material comprises a close-weave fabric of a sufficiently close weave to be waterproof and breathable. 21. The orthopedic pet cushion as recited in claim 19, wherein said breathable, waterproof, flexible, and MVT membrane material of the protective liner is naturally oleophobic, anti-dust mite, anti-odor, anti-bacterial, anti-stain, and anti-static. 22. The orthopedic pet cushion as recited in claim 19, wherein said outer fabric cover is comprised of a top surface, a bottom surface, and peripheral side walls disposed between said top and bottom surfaces. 23. The orthopedic pet cushion as recited in claim 19, wherein said protective liner of flexible, breathable, waterproof, MVT membrane material is sealed closed, by a method such as but not limited to sewing, gluing, or thermal bonding, around said padding layer of slow-recovery visco-elastic foam and said supporting padding layer, in such a close-fitting and tight manner that the protective liner does not allow for the padding layers, of said slow recovery visco-elastic foam and said supporting padding, to shift or move about within the said protective liner. 24. The cushion as recited in claim 19 wherein said cushion has numerous overall geometric shape possibilities, as in having a generally square shape, as in having a generally round shape, as in having a generally rectangular shape, as in having a generally semi-circular shape, as in having a generally triangular shape, or as in having a generally pie-shaped shape. 25. The orthopedic pet as recited in claim 19 wherein said cushion may be used by domestic pets or humans. 26. Orthopedic memory foam pet cushion, the pet cushion relieves painful arthritic joints, sore muscles and hip dysplasia of older animals and provides preventative care for younger animals, the orthopedic memory foam pet cushion comprising: (a) A padding layer of slow recovery visco-elastic foam; (b) a supporting layer, said supporting layer received under said padding layer of slow recovery visco-elastic foam for providing additional cushioning thereunder; (c) a protective liner of a waterproof, breathable, flexible material, said liner enclosing said padding layer of slow recovery visco-elastic foam and said supporting layer; and (d) a washable fabric cover, said washable fabric cover enclosing said padding layer of slow recovery visco-elastic foam, said supporting layer, and said protective liner. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates in general to a pet cushion and more particularly, but not by way of limitation, to a pet cushion of orthopedic slow recovery visco-elastic foam providing orthopedic support, with a protective liner of a waterproof, breathable, flexible material enclosing the visco-elastic foam padding and the support padding while protecting the padding materials from liquids of all nature yet allowing for airflow and breathability of the padding layers it serves to enclose. 2. Description of the Prior Art Pets are an important part of the family. Pet owners desire to provide the most comfortable pet cushions and beds as possible; particularly as our pets age this becomes even more important. Older animals often suffer from arthritis, and/or joint and muscle problems making sleeping or laying down for the animal uncomfortable. Most pet cushions are made with a padding material and a fabric cover, but do not address any orthopedic aspects for the pet. Typically most pet cushions are made with common polyurethane foam. Common polyurethane foams (high resilience foams) are formulated to be resilient, resisting pressures and pushing against the source of impression. Logically, the foams recovery pressure is greatest at point were the subject is causing the greatest impression (e.g. hips, shoulders, leg joints). With seating, sleeping and other cushioning support surfaces, those pressures generated by common foam become sources of discomfort, as circulation is constricted by the upward force of the foam. These pressure points can, in clinical terms, contribute to the breakdown of skin resulting in the development of pressure ulcers. Manufactured by an exclusive process, slow recovery visco-elastic foam is a unique and separate category of foam having characteristics different than all other types of foam. Slow recovery visco-elastic foam can double the surface contact area decreasing the pressure on bony prominences and facilitating blood flow. Slow recovery visco-elastic foam possesses the characteristics of high energy absorbent properties and temperature softening behavior. These properties produce a fluid and firm effect so that the material dissipates energy away from the body. These qualities provide for an exceptionally comfortable cushion as well as being orthopedically beneficial. As referenced in Introducing the Pressure Support Surfaces from Kaymed by Pritchard, Barbara in The British Journal of Nursing, 2001, Vol 10, No. 21. Slow recovery visco-elastic foam is a polymer with a gel-like feel which, through its sensitivity to temperature, recognizes shape and pressure and adjusts to distribute load as evenly as possible. It simulates a floatation effect. This provides the orthopedic effect of reducing pressure points while giving additional comfort to the animal using the cushion. Typically animal cushions in the prior art use a cushioning material of polyester, nylon, high resilience foam, or cotton and possibly a liner which encloses the padding materials. The cushioning materials, without a waterproof liner, can absorb liquids such as urine, blood, animal saliva, and other spilled liquids to the point of saturation making the cushion unsanitary and unhealthy. After a period of use, these beds become foul smelling. In time, the cushion will promote bacterial growth due to the moisture and the body heat of the animal as well as possibly infested with mites and fleas. Cushions can be difficult if not impossible to wash due to their size or material of construction. If the cushion cannot be cleaned, the only remedy is to replace the entire padding which can become costly. Typically, if the prior art had a liner component enclosing the padding materials it was at best of a water repellent nature only and thus not impermeable to fluids, or of an absorbent nature trapping and retaining the fluid. Technology has introduced numerous high performance fabrics often used in performance outerwear or tents. Waterproof, breathable, and flexible fabrics are now manufactured by numerous sources, under numerous brand names, and are easily available to consumers. These fabrics achieve the waterproof qualities by a close weave fabric, or rely upon either the hydrophilic (water loving) or microporous qualities of materials which come as either a coating or a laminated film. The quality of breathability is achieved as the molecular chains of hydrophilic material are used as stepping stones by water molecules. The molecules are passed from chain to chain by the force of the temperature/heat differential, until they are released to the outside. Water droplets cannot pass back across the fabric for it is non-porous. These microporous materials are created to have tiny holes within their structure. These holes are large enough for water vapor molecules to pass through yet many times too small to allow the passage of water droplets. A protective liner of a waterproof, breathable, flexible material would protect the cushion padding from absorbing liquids yet allow for airflow which maintains the loft of the padding materials while maintaining the comfort of the cushion long term. In addition, these fabrics are strong, durable, and resist odors and stains making them an ideal fabric of a protective liner in a pet cushion. Most dirt contains oil. As polyester and nylon are both oil-based fibers, they are attracted to oily dirt, creating a bond between the dirt and the fiber, making it difficult to wash successfully. When dirt falls on hydrophilic fabrics, it rests on a bed of hydrophilic molecules keeping dirt away from the oil-based fabrics. The hydrophilic molecules attract and draw water and soap under the dirt allowing it to easily lift off. Prior art using polyester or nylon materials would prove more difficult to clean than the waterproof, breathable, flexible fabric suggested in the present invention. There are no examples in prior art which combine slow recovery visco-elastic foam with a protective liner of a waterproof, breathable, flexible material in a cushion or a pet cushion. A variety of pet cushions, beds or pads are available for domestic animals. U.S. Pat. No. 3,902,456 granted to David features a cloth-covered cushion. U.S. Pat. No. 5,002,014 granted to Albin features woven polyester strands coated with polyvinyl chloride impervious to liquid and uses polystyrene beads as the cushioning material. U.S. Pat. No. 5,119,763 granted to Crabtree features an orthopedic pet bed which the orthopedic support is from the quilting pattern fashioned on the filling material. U.S. Pat. No. 5,144,911 granted to Moore features moisture repelling mattress liner and a water repellent cover with the four basic components which are detachable and removable from each other. U.S. Pat. No. 5,226,384 granted to Jordan features animal beds whose main functions are pest-resistance and damage resistance using a KEVLAR aramid sheet and a MYLAR polyester sheet. Since neither KEVLAR nor MYLAR are soft comfortable fabrics, a removable cushion is place on top of the shell in order to offer comfort to the animal. Neither KEVLAR nor MYLAR is a flexible material, and MYLAR is very difficult to cut in order to construct the animal bed. U.S. Pat. No. 5,265,558 granted to Schonrock features molding a one-piece foam bed with a liquid-impermeable closed pore skin. This bed can be used with or without a cover. U.S. Pat. No. 5,515,811 granted to McAllister features a cushion for an animal, preferably a cat, which is a material of a matted web of layered, electrostatic fibers. This cushion is uncovered. U.S. Pat. No. 5,588,393 granted to Heilborn II is a pet bed of a collapsible nature. U.S. Pat. No. 5,685,257 granted to Fiebus features the use of several absorbent layers under the cushion cover with the center most layers being fluid impermeable. U.S. Pat. No. 5,715,772 granted to Kamrath et al. features an absorbent pad for absorbing pet urine with a one-way moisture barrier. U.S. Pat. No. 5,724,911 granted to McAlister features raw, unwoven, uncovered polyester. U.S. Pat. No. 6,173,675 granted to Licciardo features aromatherapy to enhance certain behaviors of the animals that use the mat. U.S. Pat. No. 6,508,200 granted to Remis features a support cushion wherein the variable support is from helical springs. A variety of support pads and mattresses are available. U.S. Pat. No. 3,968,530 granted to Dyson features a gel-like fluid; U.S. Pat. No. 4,614,000 granted to Mayer features conical-shaped bubble supports; U.S. Pat. No. 4,706,313 granted to Murphy features foam blocks that can be selectively placed; U.S. Pat. No. 4,777,681 granted to Luck, et al. features foamed material with a plurality of slits; U.S. Pat. No. 4,780,921 granted to Lahn, et al features a cover for a therapeutic support cushion having two separate chambers; and U.S. Pat. No. 5,249,320 granted to Moretz features a reservoir for moisture. Such pet cushions, mattresses, and mats have been introduced with varying degrees of success. The prior art pet beds however, fail to address orthopedic benefits or the protective benefits of a waterproof yet breathable liner in a pet cushion. The need has arisen for a pet cushion that offers the orthopedic benefits of slow recovery visco-elastic foam with a protective liner that allows the visco-elastic foam to breath while protecting it from liquids of all kinds. Visco-elastic foam is a state-of-the-art material providing the user the therapeutic benefits of even pressure distribution without constricting blood circulation and thereby lessening the risk of pressure points and user discomfort. These qualities provide for an exceptionally comfortable cushion as well as being therapeutically beneficial for animals suffering from arthritis and/or joint and muscle ailments. The liner material takes advantage of the current high performance materials offering waterproof yet breathable and easily cleanable characteristics which creates a hygienic environment for the cushion user. SUMMARY OF THE INVENTION The primary object of the present invention is to provide a orthopedic pet cushion, made with slow recovery visco-elastic foam, that will overcome the shortcoming of the prior art devices. Another object of the present invention is to use a material known to have the orthopedic properties of sensitivity to temperature, recognition of shape and pressure, and the ability to adjust and distribute load as evenly as possible which provides the orthopedic benefits of decreasing the pressure on the bony prominences and facilitating blood flow. Currently the only material known to have the above listed qualities is slow recovery visco-elastic foam. Another objective of the present invention to provide an additional second padding layer to the slow recovery visco-elastic foam padding which will give the very flexible visco-elastic foam padding additional support and stability while adding additional overall cushioning for added comfort. It is another object of the present invention to provide protection of the padding materials from liquids by a waterproof liner. This waterproof material used for the liner may naturally offer oleophobic, anti-dust mite, anti-odor, anti-bacterial, anti-stain, or anti-static properties in addition to its waterproof property. It is yet another object of the present invention to provide a waterproof liner material that is also breathable and flexible. The ability of the waterproof liner to breathe allows for airflow and maintains cushion loft for continuing comfort. The flexibility of the liner material is necessary so the liner does not hamper the comfort or cushioning ability of the padding it serves to enclose and protect. It is another object of the present invention to provide protection of the padding materials. This protection is achieved by a protective liner of a waterproof, breathable, flexible material which totally encloses all padding materials and is sealed shut by an appropriate means such as sewing, gluing, thermal bonding or the like. This protective liner is sealed around the padding materials in such a tight and close-fitting manner, that it prevents the two padding materials from shifting or moving about within the protective liner. It is yet another object of the present invention to provide an outer cover of a material that is soft, comfortable, hypoallergenic, absorbent, resistant to the adherence of stains, and is highly resistant to breakage or tearing in any direction. The resealable closure allows for easy removal of the cover for washing. The cover is made of a fabric that may be conventionally laundered repeatedly. To that end, an orthopedic cushion, for pets or humans, which includes a cushion formed from a plurality of layers including two padding layers, one of slow recovery visco-elastic foam and the second of a material that supports the visco-elastic foam while adding additional padding. Then a protective liner made from a waterproof, breathable, flexible material which completely encloses the two padding layers and is sealed around the padding layers in such a tight and close-fitting manner as to prevent shifting or moving about of the padding layers within the protective liner. Finally, around the enclosed padding layers and their protective liner, is a soft comfortable washable cover. This outer cover may be easily removed for washing. The second supporting padding layer may be made from a textile-based, foam, or rubber material. The waterproof, breathable, flexible protective liner material may achieve the properties of waterproof and breathablilty by a number of methods such as, but not limited to, utilizing a hydrophilic coating or laminate, a microporous coating or laminate, a bi-component coating or laminate, a monolithic membrane, a moisture-vapor-transmission (MVT) membrane, or a microfiber of sufficiently close weave as to be waterproof and breathable. The outer washable cover is comprised of a top surface, a bottom surface and peripheral side walls between the top and bottom surfaces. This outer fabric cover has a releasable closure so that fabric cover may be easily removed washing. The orthopedic cushion may be constructed in any geometric shape deemed necessary by the user's space needs. Suggested shapes would include, but not limited to, square, round, rectangular, triangular, semi-circle, or pie-shaped. Further objects of the invention will appear as the description proceeds. To accomplish the above and related objects, this invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific construction illustrated and described within the scope of the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates in general to a pet cushion and more particularly, but not by way of limitation, to a pet cushion of orthopedic slow recovery visco-elastic foam providing orthopedic support, with a protective liner of a waterproof, breathable, flexible material enclosing the visco-elastic foam padding and the support padding while protecting the padding materials from liquids of all nature yet allowing for airflow and breathability of the padding layers it serves to enclose. 2. Description of the Prior Art Pets are an important part of the family. Pet owners desire to provide the most comfortable pet cushions and beds as possible; particularly as our pets age this becomes even more important. Older animals often suffer from arthritis, and/or joint and muscle problems making sleeping or laying down for the animal uncomfortable. Most pet cushions are made with a padding material and a fabric cover, but do not address any orthopedic aspects for the pet. Typically most pet cushions are made with common polyurethane foam. Common polyurethane foams (high resilience foams) are formulated to be resilient, resisting pressures and pushing against the source of impression. Logically, the foams recovery pressure is greatest at point were the subject is causing the greatest impression (e.g. hips, shoulders, leg joints). With seating, sleeping and other cushioning support surfaces, those pressures generated by common foam become sources of discomfort, as circulation is constricted by the upward force of the foam. These pressure points can, in clinical terms, contribute to the breakdown of skin resulting in the development of pressure ulcers. Manufactured by an exclusive process, slow recovery visco-elastic foam is a unique and separate category of foam having characteristics different than all other types of foam. Slow recovery visco-elastic foam can double the surface contact area decreasing the pressure on bony prominences and facilitating blood flow. Slow recovery visco-elastic foam possesses the characteristics of high energy absorbent properties and temperature softening behavior. These properties produce a fluid and firm effect so that the material dissipates energy away from the body. These qualities provide for an exceptionally comfortable cushion as well as being orthopedically beneficial. As referenced in Introducing the Pressure Support Surfaces from Kaymed by Pritchard, Barbara in The British Journal of Nursing, 2001, Vol 10, No. 21. Slow recovery visco-elastic foam is a polymer with a gel-like feel which, through its sensitivity to temperature, recognizes shape and pressure and adjusts to distribute load as evenly as possible. It simulates a floatation effect. This provides the orthopedic effect of reducing pressure points while giving additional comfort to the animal using the cushion. Typically animal cushions in the prior art use a cushioning material of polyester, nylon, high resilience foam, or cotton and possibly a liner which encloses the padding materials. The cushioning materials, without a waterproof liner, can absorb liquids such as urine, blood, animal saliva, and other spilled liquids to the point of saturation making the cushion unsanitary and unhealthy. After a period of use, these beds become foul smelling. In time, the cushion will promote bacterial growth due to the moisture and the body heat of the animal as well as possibly infested with mites and fleas. Cushions can be difficult if not impossible to wash due to their size or material of construction. If the cushion cannot be cleaned, the only remedy is to replace the entire padding which can become costly. Typically, if the prior art had a liner component enclosing the padding materials it was at best of a water repellent nature only and thus not impermeable to fluids, or of an absorbent nature trapping and retaining the fluid. Technology has introduced numerous high performance fabrics often used in performance outerwear or tents. Waterproof, breathable, and flexible fabrics are now manufactured by numerous sources, under numerous brand names, and are easily available to consumers. These fabrics achieve the waterproof qualities by a close weave fabric, or rely upon either the hydrophilic (water loving) or microporous qualities of materials which come as either a coating or a laminated film. The quality of breathability is achieved as the molecular chains of hydrophilic material are used as stepping stones by water molecules. The molecules are passed from chain to chain by the force of the temperature/heat differential, until they are released to the outside. Water droplets cannot pass back across the fabric for it is non-porous. These microporous materials are created to have tiny holes within their structure. These holes are large enough for water vapor molecules to pass through yet many times too small to allow the passage of water droplets. A protective liner of a waterproof, breathable, flexible material would protect the cushion padding from absorbing liquids yet allow for airflow which maintains the loft of the padding materials while maintaining the comfort of the cushion long term. In addition, these fabrics are strong, durable, and resist odors and stains making them an ideal fabric of a protective liner in a pet cushion. Most dirt contains oil. As polyester and nylon are both oil-based fibers, they are attracted to oily dirt, creating a bond between the dirt and the fiber, making it difficult to wash successfully. When dirt falls on hydrophilic fabrics, it rests on a bed of hydrophilic molecules keeping dirt away from the oil-based fabrics. The hydrophilic molecules attract and draw water and soap under the dirt allowing it to easily lift off. Prior art using polyester or nylon materials would prove more difficult to clean than the waterproof, breathable, flexible fabric suggested in the present invention. There are no examples in prior art which combine slow recovery visco-elastic foam with a protective liner of a waterproof, breathable, flexible material in a cushion or a pet cushion. A variety of pet cushions, beds or pads are available for domestic animals. U.S. Pat. No. 3,902,456 granted to David features a cloth-covered cushion. U.S. Pat. No. 5,002,014 granted to Albin features woven polyester strands coated with polyvinyl chloride impervious to liquid and uses polystyrene beads as the cushioning material. U.S. Pat. No. 5,119,763 granted to Crabtree features an orthopedic pet bed which the orthopedic support is from the quilting pattern fashioned on the filling material. U.S. Pat. No. 5,144,911 granted to Moore features moisture repelling mattress liner and a water repellent cover with the four basic components which are detachable and removable from each other. U.S. Pat. No. 5,226,384 granted to Jordan features animal beds whose main functions are pest-resistance and damage resistance using a KEVLAR aramid sheet and a MYLAR polyester sheet. Since neither KEVLAR nor MYLAR are soft comfortable fabrics, a removable cushion is place on top of the shell in order to offer comfort to the animal. Neither KEVLAR nor MYLAR is a flexible material, and MYLAR is very difficult to cut in order to construct the animal bed. U.S. Pat. No. 5,265,558 granted to Schonrock features molding a one-piece foam bed with a liquid-impermeable closed pore skin. This bed can be used with or without a cover. U.S. Pat. No. 5,515,811 granted to McAllister features a cushion for an animal, preferably a cat, which is a material of a matted web of layered, electrostatic fibers. This cushion is uncovered. U.S. Pat. No. 5,588,393 granted to Heilborn II is a pet bed of a collapsible nature. U.S. Pat. No. 5,685,257 granted to Fiebus features the use of several absorbent layers under the cushion cover with the center most layers being fluid impermeable. U.S. Pat. No. 5,715,772 granted to Kamrath et al. features an absorbent pad for absorbing pet urine with a one-way moisture barrier. U.S. Pat. No. 5,724,911 granted to McAlister features raw, unwoven, uncovered polyester. U.S. Pat. No. 6,173,675 granted to Licciardo features aromatherapy to enhance certain behaviors of the animals that use the mat. U.S. Pat. No. 6,508,200 granted to Remis features a support cushion wherein the variable support is from helical springs. A variety of support pads and mattresses are available. U.S. Pat. No. 3,968,530 granted to Dyson features a gel-like fluid; U.S. Pat. No. 4,614,000 granted to Mayer features conical-shaped bubble supports; U.S. Pat. No. 4,706,313 granted to Murphy features foam blocks that can be selectively placed; U.S. Pat. No. 4,777,681 granted to Luck, et al. features foamed material with a plurality of slits; U.S. Pat. No. 4,780,921 granted to Lahn, et al features a cover for a therapeutic support cushion having two separate chambers; and U.S. Pat. No. 5,249,320 granted to Moretz features a reservoir for moisture. Such pet cushions, mattresses, and mats have been introduced with varying degrees of success. The prior art pet beds however, fail to address orthopedic benefits or the protective benefits of a waterproof yet breathable liner in a pet cushion. The need has arisen for a pet cushion that offers the orthopedic benefits of slow recovery visco-elastic foam with a protective liner that allows the visco-elastic foam to breath while protecting it from liquids of all kinds. Visco-elastic foam is a state-of-the-art material providing the user the therapeutic benefits of even pressure distribution without constricting blood circulation and thereby lessening the risk of pressure points and user discomfort. These qualities provide for an exceptionally comfortable cushion as well as being therapeutically beneficial for animals suffering from arthritis and/or joint and muscle ailments. The liner material takes advantage of the current high performance materials offering waterproof yet breathable and easily cleanable characteristics which creates a hygienic environment for the cushion user. | <SOH> SUMMARY OF THE INVENTION <EOH>The primary object of the present invention is to provide a orthopedic pet cushion, made with slow recovery visco-elastic foam, that will overcome the shortcoming of the prior art devices. Another object of the present invention is to use a material known to have the orthopedic properties of sensitivity to temperature, recognition of shape and pressure, and the ability to adjust and distribute load as evenly as possible which provides the orthopedic benefits of decreasing the pressure on the bony prominences and facilitating blood flow. Currently the only material known to have the above listed qualities is slow recovery visco-elastic foam. Another objective of the present invention to provide an additional second padding layer to the slow recovery visco-elastic foam padding which will give the very flexible visco-elastic foam padding additional support and stability while adding additional overall cushioning for added comfort. It is another object of the present invention to provide protection of the padding materials from liquids by a waterproof liner. This waterproof material used for the liner may naturally offer oleophobic, anti-dust mite, anti-odor, anti-bacterial, anti-stain, or anti-static properties in addition to its waterproof property. It is yet another object of the present invention to provide a waterproof liner material that is also breathable and flexible. The ability of the waterproof liner to breathe allows for airflow and maintains cushion loft for continuing comfort. The flexibility of the liner material is necessary so the liner does not hamper the comfort or cushioning ability of the padding it serves to enclose and protect. It is another object of the present invention to provide protection of the padding materials. This protection is achieved by a protective liner of a waterproof, breathable, flexible material which totally encloses all padding materials and is sealed shut by an appropriate means such as sewing, gluing, thermal bonding or the like. This protective liner is sealed around the padding materials in such a tight and close-fitting manner, that it prevents the two padding materials from shifting or moving about within the protective liner. It is yet another object of the present invention to provide an outer cover of a material that is soft, comfortable, hypoallergenic, absorbent, resistant to the adherence of stains, and is highly resistant to breakage or tearing in any direction. The resealable closure allows for easy removal of the cover for washing. The cover is made of a fabric that may be conventionally laundered repeatedly. To that end, an orthopedic cushion, for pets or humans, which includes a cushion formed from a plurality of layers including two padding layers, one of slow recovery visco-elastic foam and the second of a material that supports the visco-elastic foam while adding additional padding. Then a protective liner made from a waterproof, breathable, flexible material which completely encloses the two padding layers and is sealed around the padding layers in such a tight and close-fitting manner as to prevent shifting or moving about of the padding layers within the protective liner. Finally, around the enclosed padding layers and their protective liner, is a soft comfortable washable cover. This outer cover may be easily removed for washing. The second supporting padding layer may be made from a textile-based, foam, or rubber material. The waterproof, breathable, flexible protective liner material may achieve the properties of waterproof and breathablilty by a number of methods such as, but not limited to, utilizing a hydrophilic coating or laminate, a microporous coating or laminate, a bi-component coating or laminate, a monolithic membrane, a moisture-vapor-transmission (MVT) membrane, or a microfiber of sufficiently close weave as to be waterproof and breathable. The outer washable cover is comprised of a top surface, a bottom surface and peripheral side walls between the top and bottom surfaces. This outer fabric cover has a releasable closure so that fabric cover may be easily removed washing. The orthopedic cushion may be constructed in any geometric shape deemed necessary by the user's space needs. Suggested shapes would include, but not limited to, square, round, rectangular, triangular, semi-circle, or pie-shaped. detailed-description description="Detailed Description" end="lead"? Further objects of the invention will appear as the description proceeds. To accomplish the above and related objects, this invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific construction illustrated and described within the scope of the appended claims. detailed-description description="Detailed Description" end="tail"? | 20040412 | 20070306 | 20051013 | 62214.0 | 2 | NGUYEN, SON T | ORTHOPEDIC PET CUSHION | SMALL | 0 | ACCEPTED | 2,004 |
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10,822,653 | ACCEPTED | Air cleaning robot and system thereof | An air cleaning robot and a system thereof which are capable of performing air cleaning while traveling around a predetermined area. The air cleaning robot includes a robot body, a driving part for driving a plurality of wheels disposed at lower portions of the robot body, an air cleaning part disposed in the robot body, for drawing-in dust-ladened air from a cleaning area, air filtering, and discharging cleaned air. A controller is disposed in the robot body for controlling the air cleaning part and the driving part. Accordingly, since the air cleaning robot and the system thereof perform air cleaning while traveling automatically around a predetermined area, there is an improvement in a residential household, living environment, and less of an inconvenience to operate. | 1. An air cleaning robot, which performs air cleaning while traveling around a predetermined area, comprising: a robot body; a driving part for driving a plurality of wheels disposed at lower portions of the robot body; an air cleaning part disposed in the robot body, for drawing-in dust-ladened air from a cleaning area, air filtering, and discharging cleaned air; and a controller disposed in the robot body for controlling the air cleaning part and the driving part. 2. The air cleaning robot as claimed in claim 1, wherein the controller controls the driving part and the air cleaning part simultaneously which allows the robot to both travel around the predetermined area while simultaneously air cleaning. 3. The air cleaning robot as claimed in claim 1, wherein the driving part comprises: a pair of driving motors disposed in the robot body and driven by power supplied respectively thereto; a pair of driving wheels rotated by the pair of driving motors; a pair of driven wheels proceeding the pair of driving wheels; and a power transmitting means connecting the driving wheels and the driven wheels. 4. The air cleaning robot as claimed in claim 3, wherein the power transmitting means includes a timing belt. 5. The air cleaning robot as claimed in claim 1, wherein the robot body is connected to a body cover and forms an exterior of the air cleaning robot, and the air cleaning part comprises: a suction driving source drawing-in the dust-ladened air from the predetermined area; a suction port connected to one side of the body cover; a discharge port connected to another side of the body cover to discharge cleaned air; an air cleaning duct disposed in the robot body in communication with the suction port through to the discharge port; and a plurality of filters disposed in the air cleaning duct for filtering drawn-in air. 6. The air cleaning robot as claimed in claim 5, wherein the suction port is disposed at one side of a front portion of the body cover. 7. The air cleaning robot as claimed in claim 5, wherein the suction port is disposed on one side of an upper portion of the body cover. 8. The air cleaning robot as claimed in claim 6, wherein the discharge port is disposed at another other side of the front portion of the body cover. 9. The air cleaning robot as claimed in claim 7, wherein the discharge port is disposed at another side of a front portion of the body cover. 10. The air cleaning robot as claimed in claim 6, wherein the discharge port is disposed at another side of an upper potion of the body cover. 11. The air cleaning robot as claimed in claim 7, wherein the discharge port is disposed at another side of the upper portion of the body cover. 12. The air cleaning robot as claimed in claim 5, wherein the suction driving source is disposed inside the air cleaning duct to draw-in air. 13. The air cleaning robot as claimed in claim 5, wherein the plurality of filters comprises: a first filter for filtering out relatively large dust particles from drawn-in air; and a second filter for removing minute dust particles and unpleasant odors. 14. An air cleaning robot system which comprises a driving part for driving a plurality of wheels and a controller for controlling the driving part, further comprising an air cleaning part controlled by a controller, the system automatically traveling along a predetermined area while simultaneously air cleaning. 15. The system as claimed in claim 14, wherein the air cleaning part comprises a suction driving source for drawing-in dust-ladened air from the predetermined area, a suction port through which air is drawn-in, a discharge port for discharging cleaned air therethrough, at least one filter for filtering drawn-in air, and, when the suction driving source is driven by the controller, air is drawn-in through the suction port and filtered by the filter, and cleaned air is discharged through the discharge port. | REFERENCE TO RELATED APPLICATIONS This application claims priority to copending Korean Patent Application No. 2003-52438 filed on Jun. 29, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. CROSS-REFERENCE RO RELATED APPLICATIONS This application is related to copending Korean Patent Application Nos. 10-2003-00074216, filed Feb. 6, 2003; 10-2003-0013961, filed Mar. 6, 2003; 10-2003-0029242, filed Mar. 9, 2003; and 10-2003-51139, filed Jul. 24, 2003, whose disclosures are entirely incorporated herein by reference. FIELD OF THE INVENTION The present invention relates to an air cleaning robot and a system thereof, and more particularly, to an air cleaning robot and a system thereof which cleans ambient air while traveling around a predetermined area. BACKGROUND OF THE INVENTION Generally, a robot cleaner can determine a distance to an obstacle such as furniture, office appliances, or a wall in a predetermined area, by using a distance sensor, and avoids a collision with the obstacle while it performs an assigned task. The cleaner robot includes a robot body, a driving part for driving the robot body, a controller for controlling the driving part, a memory device, and a transmitting and receiving part for inputting and outputting a command. The assigned task includes work vacuuming a floor, and that task is usually performed upon receipt of a command from an operator. Although there are many robot cleaners available, there has been almost no air cleaning robot that performs air cleaning. Due to the recent alarms prompted by the Asian Dust and the Severe Acute Respiratory Syndrome (SARS), people have become more concerned about the health and cleaner and fresh air. Thus, a heretofore unaddressed need exists in the industry for a robot with an air cleaning function, to address the aforementioned deficiencies and inadequacies. SUMMARY OF THE INVENTION The present invention has been developed in order to solve the above shortcomings in the related art. Accordingly, an aspect of the present invention provides an air cleaning robot and a system thereof, which is capable of performing an air cleaning while traveling around a predetermined area. The above aspect is achieved by providing an air cleaning robot, which performs air cleaning while traveling around a predetermined area. The air cleaning robot comprises a robot body, a driving part for driving a plurality of wheels disposed at lower portions of the robot body, and an air cleaning part disposed in the robot body for drawing-in dust-ladened air from a cleaning area, filtering the air, and discharging cleaned air. A controller is disposed in the robot body for controlling the air cleaning part and the driving part. The controller controls the driving part and the air cleaning part simultaneously so the robot travels around the predetermined area and, simultaneously performs air cleaning. The driving part may include a pair of driving motors disposed in the robot body which are driven by supplied power, a pair of driving wheels rotated by the pair of driving motors, a pair of driven wheels proceeding the pair of driving wheels, and a power transmitting means connecting the driving wheels and the driven wheels. In one embodiment, the power transmitting means includes a timing belt, and the robot body is connected with a body cover to form an exterior of the air cleaning robot. The air cleaning part includes a suction driving source drawing-in dust-ladened air from the predetermined area, a suction port connected to one side of the body cover, and a discharge port connected to another side of the body cover to discharge the cleaned air, an air cleaning duct disposed in the robot body and in communication with the suction port and further to the discharge port. A plurality of filters are disposed in the air cleaning duct for filtering the drawn-in air. The suction port may be disposed at one side of a front portion of the body cover, and also may be disposed on one side of an upper portion of the body cover. The discharge port may also be disposed at the other side of the front portion of the body cover, and may be disposed at the other side of the upper portion of the body cover. In another embodiment, the suction driving source is disposed inside the air cleaning duct to draw-in air. The plurality of filters comprise a first filter for filtering out relatively large dust particles from drawn-in air, and a second filter for removing the minute dust particles and unpleasant odors. The above aspect is also achieved by providing an air cleaning robot system, which includes a driving part for driving a plurality of wheels and a controller for controlling the driving part. The air cleaning robot system further comprises an air cleaning part controlled by a controller with the system traveling automatically along a predetermined area while simultaneously air cleaning. The air cleaning part may include a suction driving source for drawing-in dust-ladened air from the predetermined area, a suction port through which air is drawn-in, and a discharge port for discharging cleaned air. The air cleaning may further include at least one filter for filtering drawn-in air. When the suction driving source is driven by the controller, air is drawn-in through the suction port and filtered by the filter. Cleaned air is discharged through the discharge port. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a drawing showing a perspective view of an air cleaning robot with an air cleaning part according to one embodiment of the present invention; FIG. 2 is a drawing showing a perspective view of the air cleaning robot of FIG. 1 in which an upper cover is removed; FIG. 3 is a plan view drawing showing the air cleaning part of the air cleaning robot of FIG. 1; FIG. 4 is a block diagram showing a central control device of an air cleaning robot system according to one embodiment; and FIG. 5 is a drawing showing a perspective view of an air cleaning robot with an air cleaning part according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1-4, an air cleaning robot and a system according to one embodiment of the present invention are described in detail hereinbelow, in which reference sign ‘I’ indicates a forwarding direction of the robot. Referring to FIGS. 1-4, the air cleaning robot mainly includes a body 10, a body cover 11 connected to the body 12 to form the exterior of the air cleaning robot, a driving part 20, an upper camera 30, a front camera 32, an obstacle sensor 34, an air cleaning part 60, a controller 40, a memory device 41, and a transmitting and receiving part 43. The driving part 20 includes two driven wheels 21 disposed at both front sides of the robot body 11, two driving wheels 22 disposed at both rear sides of the robot body 11, a pair of motors 24 rotationally driving the two rear driving wheels 22, respectively, and a power transmitting means 25 for transmitting power from the rear driving wheels 22 to the front driven wheels 21. The power transmitting means 25 includes a timing belt (not shown) or a gear pulley (not shown). The driving part 20 rotates the pair of motors 24 independently in a clockwise direction or a counter-clockwise direction in accordance with a control signal from the controller 40. The traveling direction of the cleaning robot 10 is determined by rotating the motors 24 at respective RPMs. The front camera 32 is disposed in the body 12 to photograph front images and output the photographed images to the controller 40. The upper camera 30 is disposed in the body 12 to photograph upward images and output the photographed images to the controller 40. In another embodiment, the upper camera 30 employs a fish eye lens (not shown). Since the construction of the fish eye lens is disclosed in the Korean Publication Nos. 1996-7005245, 1997-48669, and 1994-22112 and is being marketed by various fish eye lens manufactures, a detailed description thereof is omitted. The obstacle sensors 34 are arranged along a circumference of the body 12 at a predetermined interval to transmit signals to the outside and receive a reflected signal. Also, the obstacle sensor 34 may use an ultrasonic sensor emitting an ultrasonic wave and receive a reflected ultrasonic wave. The obstacle sensor 34 is used to measure a distance to an obstacle or a wall. The traveling distance sensor (not shown) connected to the controller 40 may use a rotation detecting sensor (not shown) for detecting RPMs of the driving wheels 22 and the driven wheels 21. In particular, the rotation detecting sensor may employ an encoder to detect RPMs of the motors 24. The air cleaning part 60 is disposed at an inner side of the body 12 to draw-in air from a cleaning area and filter out dust (FIG. 3). The air cleaning part 60 includes a suction driving source 61, a suction port 63 connected to one side of the body cover 11, a discharge port 65 connected to the other side of the body cover 11, an air cleaning duct 67, and a plurality of filters 69. The suction driving source 61 generates a suction force enabling dust-ladened air to be drawn-in from the cleaning area. The suction driving source 61 is disposed inside the air cleaning duct 67 to draw air in and also provide the suction force to the air cleaning part 60 in relation to movement of a driving motor (not shown), thus providing a driving force to the driving part 20 of the air cleaning robot. The suction driving source 61 can be embodied either in association with the driving motor (not shown) or separately if the suction driving source 61 provides the suction force to the air cleaning part 60. The suction driving source 61 may include a motor and a fan system. The suction port 63 is disposed in one front side or one upper side of the body cover 11, and the discharge port 65 is disposed in the other front side or the other upper side of the body cover 11. As shown in FIG. 1, the suction port 63 may be disposed in one front side of the body cover 11, while the discharge port 65 may be disposed in one rear side of the body cover 11. Thus, the positions where the suction port 63 and the discharge port 65 are disposed may be varied. For example, the suction port 63 may be disposed in one front side of the body cover 11, while the discharge port 65 may be disposed in one upper side of the body cover 11 as shown in FIG. 5. Also, there may be provided at least two suction ports 63 and at least two discharge ports 65. In that case, each suction port 63 and discharge port 65 may be disposed independently from the air cleaning duct 67, or may be connected to the air cleaning duct 67. The air cleaning duct 67 is in fluid communication with the suction port 63 through the discharge port 65 so that air drawn-in through the suction port 63 by the suction driving source 61 is discharged through the discharge port 65 via the air cleaning duct 67. As long as the fluid communication with the suction port 63 through to the discharge port 65 is ensured, the communication line may take various forms such as a straight line or a curved line. The plurality of filters 69 function to filter air drawn-in through the suction port 63. The filters 69 include a first filter 71 and a second filter 73. The first filter 71 filters out relatively larger dust particles from the air, while the second filter 73 filters out relatively minute dust particles and distasteful odors from the large dust-removed air. In another embodiment, the second filter 73 uses a commercially available hepa filter to filter bacteria, virus, molds, house dust and, minute bacteria from animals which can cause respiratory system disorder and allergies in humans. The second filter 73 may use a commercially available deodorizing filter for removing various smells. The controller 40 processes signals received through the receiving and transmitting part 43 and controls those respective components. The air cleaning robot may further comprise a key input apparatus (not shown). In that case, the key input apparatus (not shown) is formed in the body 12 and has a plurality of keys for manipulating a function setting of the air cleaning robot 10, and the controller 40 processes a key signal inputted through the key input apparatus (not shown). The controller 40 operates the driving part 20 and the air cleaning part 60, simultaneously, so that the air cleaning robot 10 performs air cleaning while traveling around a predetermined area. The memory device 41 stores the upward images photographed by the upper camera 30 and assists the controller 40 in calculating the location and traveling information. The receiving and transmitting part 43 transmits data to an external device 80 via an antenna 42 and also transmits signals received from the external device 80 via the antenna to the controller 40. The external device 80 includes a wireless relay apparatus (not shown) and a remote controller (not shown) through which data is input and output. In this embodiment, the external device 80 is a remote controller. The controller 40 controls the driving part 20 to drive the air cleaning robot to travel around a working area according to a traveling pattern, creates an image map with respect to an upward area from the upward image photographed by the upper camera 30, and stores the created image map in the memory device 41. Alternatively, when a working command is wirelessly received through the key input apparatus or from the outside, the image map can be created before a task is performed. After the creation of the image map, the controller 40 recognizes a location by using the created image map while working. That is, when a command signal for the job or task is inputted wirelessly through the key input apparatus or from the outside, the controller 40 recognizes a current location by comparing a current image inputted from the upper camera 30 or the front camera 32 with the memorized image map, and commands the driving part 20 to follow a traveling path from the current location to a target location. The work commanding signal includes a cleaning, or a monitoring by cameras 31, 32. When the air cleaning robot 10 runs along the traveling path to the target location, the driving part 20 is directed to calculate a traveling error by using a traveling distance measured by the encoder and the current location recognized by the comparison of the currently photographed image and the memorized image map, and compensate the error, thereby tracking the traveling path to the target location. While the air cleaning robot is traveling, the controller 40 commands the air cleaning part 60 to operate according to the work commanding signal. As the suction driving source 61 is driven by the controller 40, air is drawn-in through the suction port 63 and filtered by the filters 69 from the air cleaning part 60, and cleaned air is discharged through the discharge port 65. Accordingly, the air cleaning robot 10 air cleans while traveling around the predetermined area. When a user inputs a signal to stop the operation of the driving part 20 through the external device 80, the air cleaning robot 10 stops at a predetermined position, but continues air cleaning. When the user inputs a work stopping command through the external device as when air cleaning is completed, the controller 40 stops the air cleaning work and returns the air cleaning robot 10 to an initial position. The foregoing embodiment and advantages are merely exemplary and are not to be construed as limiting the present invention. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. | <SOH> BACKGROUND OF THE INVENTION <EOH>Generally, a robot cleaner can determine a distance to an obstacle such as furniture, office appliances, or a wall in a predetermined area, by using a distance sensor, and avoids a collision with the obstacle while it performs an assigned task. The cleaner robot includes a robot body, a driving part for driving the robot body, a controller for controlling the driving part, a memory device, and a transmitting and receiving part for inputting and outputting a command. The assigned task includes work vacuuming a floor, and that task is usually performed upon receipt of a command from an operator. Although there are many robot cleaners available, there has been almost no air cleaning robot that performs air cleaning. Due to the recent alarms prompted by the Asian Dust and the Severe Acute Respiratory Syndrome (SARS), people have become more concerned about the health and cleaner and fresh air. Thus, a heretofore unaddressed need exists in the industry for a robot with an air cleaning function, to address the aforementioned deficiencies and inadequacies. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention has been developed in order to solve the above shortcomings in the related art. Accordingly, an aspect of the present invention provides an air cleaning robot and a system thereof, which is capable of performing an air cleaning while traveling around a predetermined area. The above aspect is achieved by providing an air cleaning robot, which performs air cleaning while traveling around a predetermined area. The air cleaning robot comprises a robot body, a driving part for driving a plurality of wheels disposed at lower portions of the robot body, and an air cleaning part disposed in the robot body for drawing-in dust-ladened air from a cleaning area, filtering the air, and discharging cleaned air. A controller is disposed in the robot body for controlling the air cleaning part and the driving part. The controller controls the driving part and the air cleaning part simultaneously so the robot travels around the predetermined area and, simultaneously performs air cleaning. The driving part may include a pair of driving motors disposed in the robot body which are driven by supplied power, a pair of driving wheels rotated by the pair of driving motors, a pair of driven wheels proceeding the pair of driving wheels, and a power transmitting means connecting the driving wheels and the driven wheels. In one embodiment, the power transmitting means includes a timing belt, and the robot body is connected with a body cover to form an exterior of the air cleaning robot. The air cleaning part includes a suction driving source drawing-in dust-ladened air from the predetermined area, a suction port connected to one side of the body cover, and a discharge port connected to another side of the body cover to discharge the cleaned air, an air cleaning duct disposed in the robot body and in communication with the suction port and further to the discharge port. A plurality of filters are disposed in the air cleaning duct for filtering the drawn-in air. The suction port may be disposed at one side of a front portion of the body cover, and also may be disposed on one side of an upper portion of the body cover. The discharge port may also be disposed at the other side of the front portion of the body cover, and may be disposed at the other side of the upper portion of the body cover. In another embodiment, the suction driving source is disposed inside the air cleaning duct to draw-in air. The plurality of filters comprise a first filter for filtering out relatively large dust particles from drawn-in air, and a second filter for removing the minute dust particles and unpleasant odors. The above aspect is also achieved by providing an air cleaning robot system, which includes a driving part for driving a plurality of wheels and a controller for controlling the driving part. The air cleaning robot system further comprises an air cleaning part controlled by a controller with the system traveling automatically along a predetermined area while simultaneously air cleaning. The air cleaning part may include a suction driving source for drawing-in dust-ladened air from the predetermined area, a suction port through which air is drawn-in, and a discharge port for discharging cleaned air. The air cleaning may further include at least one filter for filtering drawn-in air. When the suction driving source is driven by the controller, air is drawn-in through the suction port and filtered by the filter. Cleaned air is discharged through the discharge port. | 20040413 | 20060919 | 20050203 | 60254.0 | 0 | LAWRENCE JR, FRANK M | AIR CLEANING ROBOT AND SYSTEM THEREOF | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,822,727 | ACCEPTED | Neutron detector with layered thermal-neutron scintillator and dual function light guide and thermalizing media | A broad spectrum neutron detector has a thermal neutron sensitive scintillator film interleaved with a hydrogenous thermalizing media. The neutron detector has negligible sensitivity to gamma rays and produces a strong and unambiguous signal for virtually all neutrons that interact with the hydrogenous volume. The interleaving of the layers of thermal neutron sensitive phosphors helps ensure that all parts of the thermalizing volume are highly sensitive. | 1. A broad spectrum neutron detector comprising a thermal neutron sensitive scintillator film interleaved with a hydrogenous thermalizing media. 2. The neutron detector of claim 1 wherein the thermal neutron sensitive scintillator film comprises a material selected from the group consisting of 6Li—ZnS, 10BN, and other alpha particle sensitive phosphors doped with 6Li or 10B. 3. The neutron detector of claim 1 wherein the hydrogenous thermalizing media comprises acrylic. 4. The neutron detector of claim 1 wherein the thermal neutron sensitive scintillator film has a layer thickness of about 0.1 mm to about 0.5 mm. 5. The neutron detector of claim 1 wherein the thermalizing media has a layer thickness of about 0.5 cm to about 1.5 cm. 6. The neutron detector of claim 1 further comprising a photo-sensor. 7. The neutron detector of claim 1 further comprising a wavelength shifter. 8. A portal detector comprising the neutron detector of claim 1. 9. A handheld instrument comprising the neutron detector of claim 1. 10. A neutron detector comprising a plurality of 6Li—ZnS films optically coupled to a light guide-thermalizing media comprising a plurality of acrylic layers. 11. The neutron detector of claim 10 comprising at least four 6Li—ZnS films and at least five acrylic layers. 12. The neutron detector of claim 10 wherein each of the 6Li—ZnS films has a thickness of about 0.1 mm to about 0.5 mm. 13. The neutron detector of claim 10 wherein each of the high density polyethylene layers has a thickness of about 0.5 cm to about 1.5 cm. 14. The neutron detector of claim 10 further comprising a photo-sensor. 15. The neutron detector of claim 10 further comprising a wavelength shifter. 16. A portal detector comprising the neutron detector of claim 10. 17. A handheld instrument comprising the neutron detector of claim 10. 18. A neutron detector comprising: a thermal neutron sensing scintillator comprising at least four 6Li—ZnS films interleaved with and optically coupled to a light guide-thermalizing media comprising at least five acrylic layers; a reflecting surface substantially enveloping said interleaved layers, wherein said reflecting surface comprises a tapered portion extending from an end of said interleaved layers for guiding light to a narrowed section; and a photo-sensor located at the narrowed section of the tapered portion. 19. A portal detector comprising the neutron detector of claim 18. 20. A handheld instrument comprising the neutron detector of claim 18. | FIELD OF THE INVENTION The present invention is directed to neutron detection, particularly in pass-through portal detectors or handheld instruments. DESCRIPTION OF RELATED ART There is a great need for a highly efficient sensor to simultaneously detect fission and thermal neutrons that is suitable for inclusion into small instruments currently being used in anti-terrorism applications. The primary technical challenge is to create a detector with minimal volume that still retains a usable absolute sensitivity to the wide energy spectrum of neutrons expected nearby a fission source. The classical approach has usually been to use a hydrogenous thermalizing volume and a discrete thermal neutron detector, such as a 3He counter. The term “thermalizing volume” refers to a volume of material that can slow the incoming fission neutron spectrum down to “thermal” velocities. Hydrogenous materials are particularly suitable because of the high probability of inelastic collisions of incoming fast neutrons with hydrogen atoms. These collisions quickly reduce the velocity of the neutrons without excessive absorption by nuclear reactions. Such neutron detectors have significant sensitivity only to neutrons which have been slowed down to thermal energies. In a conventional 3He counter, the volume taken up by the 3He counter must be removed at the expense of the thermalizing volume, which significantly reduces the sensitivity to the more energetic portion of the neutron distribution. Using high pressures and thin diameters can help in this situation, but the resulting device still requires a several-kilovolt power supply and takes up a great deal of precious room within a small instrument. Other technologies using either 6Li or 10B involve the dissolving of the respective atoms uniformly into a plastic or glass scintillator. This scintillator material can be in the form of sheets or as fiber optics. While these approaches have advantages in the simplicity of the materials used, they generally produce much less light per event and require much more gain in the photomultiplier tube (PMT). They generally have increased gamma ray sensitivity and usually require some type of pulse shape analysis to separate gamma from neutron events, making the resulting system more complex. Fiber optic versions of the scintillators may offer improved directionality but suffer from even greater light loss, making detection more difficult. Generally, the cost of fiber optic materials is significantly greater than bulk materials and the blended scintillators are more expensive than a simple ZnS phosphor, which is in common use in displays and CRTs. It would be desirable to develop an approach which combines the neutron detection and thermalizing volume in a way which maximizes the effective volume of the instrument for all neutron energies while still providing a high detection probability for recording neutron events even in the presence of a high gamma background. The complete system may use a small photo-multiplier tube as the readout or, with proper design and doping, a solid state photo detector as well while still producing a clear and unambiguous neutron signal. With a total solid-state approach, one also eliminates the need for very high voltages and makes the package even more compact. SUMMARY OF THE INVENTION According to one aspect of the invention, a neutron detector comprises a thermal-neutron-sensitive scintillator film interleaved with a hydrogenous thermalizing media. The hydrogenous thermalizing media does not scintillate yet substantially reduces the velocity of incoming fission neutrons to thermal energies, without producing light and while still being able to conduct the light produced from the interleaved scintillating layers on to an attached photo-detector. Gamma rays which might ionize in the primary volume of hydrogenous media convert to a recoil electron and lose kinetic energy in the hydrogenous media without the production of light. In the interleaved configuration, neutrons can slow down and scatter many times within the thermalizing volume without being absorbed (except at a scintillator interface). This approach is much more efficient at separating the effects of gamma interactions in a uniformly distributed scintillator in a similar volume. The interleaving of the layers of neutron sensitive scintillator film helps ensure that substantially all parts of the thermalizing volume are highly sensitive. Neutron sensitive scintillator films useful in the present invention include 6Li—ZnS, 10BN, and other thin layers of materials that release high energy He or H particles in neutron capture reactions. The neutron signal may be many times the gamma signal, with the ability of producing as high as 10,000 or more times rejection of gamma events and a clear electrical distinction separating the neutron pulses at the threshold. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described in more detail with reference to preferred embodiments of the invention, given only by way of example, and illustrated in the accompanying drawings in which: FIGS. 1A-1B show schematic side and partial perspective views, respectively, of a 6Li—ZnS “sandwich” detector for fission neutrons in accordance with a preferred embodiment of the present invention; FIGS. 1C-1D show schematic end views of interleaved configurations in accordance with alternative embodiments of the invention; FIG. 2A is an end view of the sandwiched 6Li detector of FIGS. 1A-1B; FIG. 2B is an end view of a conventional one-quarter inch 3He counter; FIG. 3 is a graphical comparison of a 3-cubic inch 6Li sandwich detector and a ten-inch diameter Bonner Sphere detector, showing both count rate as well as the ratio between the counters; and FIG. 4 is a graphical comparison of a 6Li sandwich detector and a Bonner Sphere detector for an “unshielded” 252Cf source. DETAILED DESCRIPTION OF THE INVENTION The neutron detector of the present invention can be used in a variety of applications, such as pass-through portal detectors, e.g., devices in which a person or object is passed through a relatively large and usually stationary device. In addition, the compact nature of the neutron detector advantageously permits its use in smaller detectors, particularly handheld devices, e.g., portable devices of such dimensions that may enable an operator to handle the device without the need of mechanical assistance. Thermal neutron sensitive scintillator films useful in the neutron detector include 6Li—ZnS, 10BN, and other thin layers of materials that release high energy He or H particles in neutron capture reactions. In general, the scintillating film has a high concentration of an element having a high probability of thermal neutron absorption with the subsequent emission of an energetic alpha, proton or triton with several MeV of energy. Also, the scintillating film should present a relatively small probability of detecting a gamma ray, and thus a composition of relatively low atomic number is preferred. Such materials can be 6Li- or 10B-enriched ZnS, 10BN, or other rare earth phosphors that contain Li or B as an additive. Suitable films include those available from St. Gobain (e.g., BC702 film) or Applied Scintillation Technology (e.g., ND scintillating screens). With reference to the embodiment illustrated in FIG. 1A-1B, a thermal neutron sensitive scintillator film 4 is interleaved with a hydrogenous thermalizing media 5 that can both slow down the fast neutrons as well as transmit the light from the scintillating films 4 to an external photo-sensor 15. Preferred hydrogenous materials have relatively high hydrogen-to-carbon ratios and are not unduly absorptive to the light from the scintillating film. For example, acrylics having a hydrogen-to-carbon ratio of about 1.6:1 are useful. Various suitable hydrogenous materials are commercially available and/or can be readily prepared by persons skilled in the art. The hydrogenous media generally does not scintillate and can reduce the velocity of incoming fission neutrons to thermal energies substantially without producing light, while still being able to conduct the light from the scintillating layers to a photo-sensor. Gamma rays which might ionize in the primary volume of hydrogenous media can convert to a recoil electron and lose kinetic energy in the hydrogenous media substantially without producing light. Any residual light that might be produced if such an electron did cross the scintillating layer generally is significantly smaller than that from the high energy alpha particle produced within the thin cross-sectional volume of the scintillator itself. Preferred hydrogenous media materials which have relatively high hydrogen concentrations and are still highly transparent include acrylic and styrene. A wide variety of other polymeric materials, examples of which include polyvinyltoluene (PVT) and polyethylene, can be used provided that the material is sufficiently clear. High density polyethylene (HPDE), when produced by extrusion, tends to be hazy or milky. HDPE is also available as a casting resin, which can be formed into very clear solid shapes that can then be polished or attached to other surfaces. The refractive index of this material is 1.54, which compares with many glasses and may also be formed into a good light guide for transmitting light out an exposed end to a photo-sensor. 6Li-doped ZnS can be obtained with either Ag or Cu doping which allows the emitted light to range from 450 to 550 nm average output wavelength in order to match different photo-sensors. The basic mode of operation of the neutron detector depends on the 6Li neutron capture reaction, which results in a 4.78 MeV alpha particle being produced. Lithium atoms introduced into the ZnS are usually in the form of LiS and enriched to about 95% in 6Li. This introduction of enriched 6LiS or 6LiF into the ZnS permits the phosphors to be very tightly blended. These sulfide phosphors are typical in the form of fine-mesh microcrystals that are settled onto a plate in an organic resin. The film usually is separated from a backing on which it is settled and can be handled as a self-supporting layer. The result is a thin, efficient layer that produces a bright flash for every capture event with an emission wavelength of about 450 nm. As illustrated in FIGS. 2A-2B, once the neutron is slowed down and scattered around in the hydrogenous media 5, the interleaved design (FIG. 2A) provides a much greater probability of the neutron interacting with a 6Li-loaded layer 4 than that provided by the coaxial geometry (FIG. 2B) used in conventional 3He counters. Because of the high scintillation efficiency of ZnS and the large energy deposited by the alpha particle, the signal from a neutron event is about 450 times larger than the average energy deposited by a 60Co gamma ray. This makes simple threshold sensing very practical even in the presence of very large gamma ray backgrounds. 6Li—ZnS layers are very thin yet can contain from about 4 to about 11 mg/cm2 of 6Li metal. The thickness of the individual 6Li—ZnS layers 4 can vary over a wide range but often ranges from about 0.1 to about 0.5 mm. The thickness of the individual hydrogenous media layers 5 also can vary over a wide range, but often ranges from about 0.5 cm to 1.5 cm. It should be understood that these thicknesses are merely exemplary and that actual layer thicknesses may differ significantly from these values. Typical areal densities of the total phosphor range from about 40 to 70 mg/cm2. This areal density corresponds to a physical thickness of about 400 microns. The actual 6Li content is typically about 4-12 mg/cm2 equivalent. With a cross section of 920 barns for the (n, α) reaction, even a single layer is quite efficient for thermal neutrons. Usually, from 1 to 10 layers of scintillator films are used, more often from about 4 to 6 layers. Thermal neutron-sensing layers 4 are interleaved with layers of hydrogenous thermalizing media 5, which also functions as a light guide. In addition, the layers of hydrogenous thermalizing media 5 may also function as wavelength shifters. This latter function may employ “wavelength shifter” plastics that are capable of absorbing light in the blue region and re-emitting it in the green region, which makes the light more easily detectable by solid-state detectors. Examples of such light-shifter plastics include BC 480, BC 482, and BC 484, all available from St. Gobain. Another advantage of using the interposing plastic layers as wavelength shifters is that it provides a more efficient means of collecting light out the end of the light guide when it enters from normal incidence from the outside. With reference to the embodiments illustrated in FIGS. 1A-1D, six to seven 6Li—ZnS layers 4 are interleaved between seven or eight acrylic layers 5 to maximize the volume of the hydrogenous media 5 and to keep the total volume to a minimum. In this way, neutrons slowed down anywhere in the hydrogenous media 5 can be detected in any of the multiple layers 4 and the light produced piped back to an optical detector 15 located at the end of the device. Light from the end area may be collected down using a taper 12, so that it can be efficiently detected by a small area, back-illuminated Si diode 15 or small photo multiplier tube (PMT). Reflective surfaces 10 surround the outermost layers of the thermalizing media layers 5 and/or scintillator film layers 4. FIG. 2A illustrates an example of the path A of an incoming thermal neutron. In the embodiments shown in FIGS. 1A-1D, the 6Li—ZnS layers 4 and the acrylic layers 5 each have a length of 2.25 inches and a cross-sectional width of 0.25 inches. The thickness of the individual 6Li—ZnS layers is approximately 0.015-0.02 inches. The thickness of the individual acrylic layers is 0.2 inches. The alternative interleaved configurations illustrated in FIGS. 1C and 1D provide a more uniform response to neutrons entering from different directions, while using the same amount of 6Li—ZnS and acrylic materials. Some principal design considerations for the neutron detector include: (1) thermal neutron capture; (2) light generation; (3) thermalization (or slowing down) of incoming fission neutrons; and (4) light capture and recording. In addition to the physical operation of the detector, there is the additional issue of identification of non-background neutrons and the overall sensitivity of the system. These are discussed briefly in the following paragraphs. The primary mechanism for thermal neutron detection is the use of the capture reaction: 6Li+ntα+2H=4.78 MeV This reaction has a relatively high cross section of 920 barns. While this is less than the 5500 barns associated with the 3He capture reaction normally used for such detectors, it generally is much easier to obtain a higher atomic density with a solid than with a gas. This tends to balance out the sensitivity as well as eliminate the lost volume taken by the gas enclosure from the remainder of the thermalizing volume. This is especially important for small instruments, such as handheld instruments, where space is very restricted. In the embodiment illustrated in FIGS. 1A-1B, commercially available films 4 of 6Li—ZnS in an acrylic binder are sandwiched between acrylic hydrogenous media layers 5, which also serve as a light guide. A typical scintillator film layer 4 contains about 4.5 mg/cm2 of 6Li metal equivalent. Using a simple estimate of the projected cross section per unit area, one obtains: Σ=η(g/cm2)×(Å/A)×σa Where: η=Areal density (g/cm2) Å=Avogadro's number=6.07×1023 atoms/gram atomic weight (GAW) A=Number of grams in a GAW=6 σa=Thermal neutron absorption cross section=920 barns An estimate for the capture-scintillator layers reveals that the projected cross section per unit area is: Σ=0.41 cm2/cm2 This projected cross section per unit area is about 40% black to incoming thermal neutrons for every scintillating film. A ZnS phosphor emits about 1.5×105 blue photons per neutron event. In the embodiments shown in FIGS. 1A-1D, several scintillator layers are interleaved with several layers of hydrogenous media. The probability of detection of a slowed down neutron is very high. Using the light guide as the thermalizing medium allows virtually the entire volume of the detector to be effective in slowing down incoming fast neutrons. Compared with the normal geometry used with a He counter of the same total outside diameter, the neutron detector of the present invention advantageously couples the thermal neutron-sensing portion of the device to the hydrogenous volume that inelastically scatters (and thus slows down) the incoming neutrons. If one compares the typical cross-sectional geometry used in the interleaved neutron detector (see FIG. 2A) to that of a 3He tube minus the separate thermalizing volume (FIG. 2B), the projected interaction area of the 6Li sensitive layers 4 is much larger for a typical neutron undergoing scattering in the thermalizing volume 5 of the interleaved geometry because of the redundancy of layers 4 in its path, assuming thermalization efficiency for fast neutrons is the same in both detectors. Because true neutron dose is based on the interactions with tissue, one often tries to simulate a larger volume of near-tissue equivalent mass to allow the incoming spectrum of neutrons to interact therewith and then to relate the total dose to the number of thermal neutrons sampled within this larger volume. The compact neutron detector can also be made more energy independent by increasing the volume of hydrogenous material to that of the thermal neutron sensitive 6LiZnS layers or equivalently by making the layers thinner. The trade-off in such optimizations is that the overall sensitivity goes down as the spectral uniformity is increased. This balance can be simulated using Monte Carlo interaction programs. In general, it was found that when compared to a 10 inch diameter Bonner Sphere which was certified up to 14 MeV neutrons, the signals from a 256Cf neutron source in a 6 inch thick HDPE shield and cadmium metal shield produced about one third of the counts per neutron event as did the compact neutron detector of the present invention. When the source was removed from the shield (increasing the fraction of faster neutrons in the spectrum), the counting rate in the compact neutron sensor was about equal to that of the Bonner Sphere. This suggests that one could improve the energy uniformity by increasing the ratio of hydrogenous material to scintillator material, but probably at the expense of more overall volume or slightly lower counting rate sensitivity. While the total probability of stopping a thermal neutron can be just as high (per unit area) in the 3He tube, the interleaved geometry provides a much higher capture angle for the randomly scattered neutrons while they are slowing though multiple inelastic collisions and approaching thermal energies, and is also more efficient at detecting a thermal event once it is finally slowed down. The incoming neutron path is straight until the first inelastic collision and then tends to be a series of straight-line segments. The neutron will continue to bounce around until it slows down and is converted by the 6Li or 3He or until it is absorbed by the hydrogen in the thermalizing media. It is readily apparent that the interleaved configuration provides a much larger angle of acceptance to interact with the active element of the detector for virtually any path that the neutron follows as it slows down. Hence, the detector of the present invention is more efficient in actually recording the event. This is especially true for very small volumes, where a 3He counter may take up a larger fraction of the overall cross-sectional area. In making the above comparisons, it is assumed that the thermalizing media in both cases had the same hydrogen-to-carbon ratio and atomic hydrogen density. In an alternative embodiment, a wavelength shifter may be employed to shift blue or UV light to a longer wavelength. These dyes are now sometimes incorporated into plastics and used for special counter geometries in high energy physics. Recent papers have shown that similar dyes can be added to cast plastics while maintaining good optical properties. While the use of wavelength shifting dyes as well as different dopings in the ZnS will optimize both the light collection and wavelength of the detected output signal, the tradeoff is that it will also increase the sensitivity to gamma rays by increasing their signals relative to those of the neutron induced alpha reaction. Most neutron sensors based on the use of ZnS scintillators have employed photo multiplier tubes that are primarily sensitive to blue light. With the use of Cu doping or with the wavelength shifter dye, it becomes very feasible to use a Si photodiode to read out light making the detector totally solid state and compact. Rather than several kilovolts, one needs only a very low voltage bias (˜35-40V), which is much easier to obtain in a handheld instrument. The expected output is equivalent to the midrange signals produced in one current CsI-PIN diode gamma spectrometer, which provides signals 15 times or more above the background noise. It is contemplated that by using photo-sensors at both ends of an elongated detector, one can also provide a convenient geometry to fit into existing portal detectors. Such a detector would have significantly higher sensitivity for detection of shielded sources as compared to an equivalent volume of hydrogenous media and a He3 counter, and would be more cost-effective. The detector preferably uses a photo multiplier tube (PMT), which is more gain sensitive but its better thermal neutron capture efficiency yields a higher counting rate for the same source strength over the 3He counter. The background of neutrons in the environment typically is about 0.007 sec−1/cm2. For a device whose projected area is 10 cm2 and whose detection efficiency is only 25%, one would expect a counting rate of about 0.0175 events per second from the detector. If one were within 5 m of a 1 kg weapons grade plutonium source, for example, the same detector would be expected to record 0.32 events per second. Such a rate is 18 times background and is relatively easy to detect, even in a short counting period. FIG. 3 is a graphical comparison of a 3-cubic inch 6Li sandwich detector and a ten-inch diameter Bonner Sphere detector, showing the count rate (cps) for a shielded 2 μg 252Cf source. The graph also shows the ratio between the counters. The variations from a constant ratio are due to the large volume of Bonner sphere distorting the 1/r2 relationship at close distances. FIG. 4 is a graphical comparison of a 6Li sandwich detector and a Bonner Sphere detector for an “unshielded” 2 μg 252Cf source. As shown in the graph, the ratio degrades but still is generally about 1. The variation is believed to be due to the relative amounts of 6Li and plastic thermalizing media in the sandwich detector. While particular embodiments of the present invention have been described and illustrated, it should be understood that the invention is not limited thereto since modifications may be made by persons skilled in the art. The present application contemplates any and all modifications that fall within the spirit and scope of the underlying invention disclosed and claimed herein. | <SOH> FIELD OF THE INVENTION <EOH>The present invention is directed to neutron detection, particularly in pass-through portal detectors or handheld instruments. | <SOH> SUMMARY OF THE INVENTION <EOH>According to one aspect of the invention, a neutron detector comprises a thermal-neutron-sensitive scintillator film interleaved with a hydrogenous thermalizing media. The hydrogenous thermalizing media does not scintillate yet substantially reduces the velocity of incoming fission neutrons to thermal energies, without producing light and while still being able to conduct the light produced from the interleaved scintillating layers on to an attached photo-detector. Gamma rays which might ionize in the primary volume of hydrogenous media convert to a recoil electron and lose kinetic energy in the hydrogenous media without the production of light. In the interleaved configuration, neutrons can slow down and scatter many times within the thermalizing volume without being absorbed (except at a scintillator interface). This approach is much more efficient at separating the effects of gamma interactions in a uniformly distributed scintillator in a similar volume. The interleaving of the layers of neutron sensitive scintillator film helps ensure that substantially all parts of the thermalizing volume are highly sensitive. Neutron sensitive scintillator films useful in the present invention include 6 Li—ZnS, 10 BN, and other thin layers of materials that release high energy He or H particles in neutron capture reactions. The neutron signal may be many times the gamma signal, with the ability of producing as high as 10,000 or more times rejection of gamma events and a clear electrical distinction separating the neutron pulses at the threshold. | 20040413 | 20070717 | 20051013 | 64962.0 | 0 | GAGLIARDI, ALBERT J | NEUTRON DETECTOR WITH LAYERED THERMAL-NEUTRON SCINTILLATOR AND DUAL FUNCTION LIGHT GUIDE AND THERMALIZING MEDIA | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,822,745 | ACCEPTED | Structure of a frame of an electric cart for a person to ride on | A frame of an electric cart includes a front part, and a rear part separable from the front part; the front part has a locating member secured on a rear end thereof; the rear part has a connecting member secured on a front end thereof for engaging the locating member, which connecting member has a spring-loaded engaging pin passed through it; the pin is made such as to be capable of engaging the locating member automatically while the rear part is being moved so as to fit the connecting member onto the locating member, thus securely joining the rear part to the front part; the engaging pin will be disengaged from the fitting portion when it is pressed at a first end, thus allowing the rear part to be separated from the front part. | 1. A frame of an electric cart for a person to ride on, comprising a front part; a rear part detachably connected to the front part; a locating seat member secured on a rear end of the front part; the locating seat member having a fitting portion, which is formed with a through hole, a gap above and communicating with the through hole, and a slope adjacent to the gap; a connecting seat member secured on a front end of the rear part for engaging the locating seat member to join the rear part to the front part; the connecting seat member having first and second lateral wall portions opposing each other; a first engaging pin passed through the lateral wall portions of the connecting seat member; the engaging pin having: (1) a pressed end portion at a first end thereof, which is passed through the first lateral wall portion; (2) a thin portion next to the pressed end portion; the thin portion being narrower than the gap of the fitting portion of the locating seat member; (3) a cone-shaped portion next to the thin portion; and (4) a stopped portion next to the cone-shaped portion; the stopped portion being wider than the gap, and narrower than the through hole of the locating seat member; and a spring connected to the engaging pin for biasing the pressed end portion of the pin further away from the second wall portion; the engaging pin being going to be pressed against the slope of the locating seat member at the cone-shaped portion thereof while the connecting seat member is being fitted onto the locating member such that the pin will be made to move in such direction as to compress the spring, and such that the pin will be passed through the gap and into the through hole of the locating seat member from the thin portion thereof, allowing the stopped portion of the pin to be through the through hole to engage the locating seat member for securing the connecting seat member to the locating seat member. 2. The frame of an electric cart as claimed in claim 1, wherein the pressed end portion of the engaging pin has a detaining element secured around it for preventing the pin from falling off from the first wall portion, and the engaging pin has an insertion portion at a second end, which is in an opposite direction of the first end; the insertion portion being passed through the spring and the second wall portion in sequence such that the spring contacts the second wall portion and the stopped portion respectively at two ends thereof. 3. The frame of an electric cart as claimed in claim 1, wherein instead of the first engaging pin, two pins, which are like the first engaging pin, are passed through respective ones of the lateral wall portions of the connecting seat member with a spring being arranged between inner ends thereof, and an axial rod is movably passed into the spring and the inner ends of the pins at two ends, and pressed end portions of both of the pins have detaining elements secured around them for preventing the pins from falling off the connecting seat member. 4. The frame of an electric cart as claimed in claim 1, wherein the locating seat member has two spaced co-axial tube portions, and a pivotal rod formed with a radial through hole is turnably passed into the co-axial tube portions with the radial hole being between the co-axial tube portions while the connecting seat member has a receiving gap thereon; a fastening member being fitted to the pivotal rod for further fastening the connecting seat member to the locating seat member; the fastening member including: (1) a pressing block for contact with the connecting seat member; (2) a rod-shaped portion formed with screw threads on a lower end thereof; the rod-shaped portion being passed through the pressing block, a second spring, and the radial through hole of the pivotal rod in sequence from a lower end, and connected to a nut at the threaded lower end thereof; and (3) a lever formed with both a pushing portion and a loosening portion at a front end thereof; the lever being pivoted to an upper end of the rod-shaped portion at the front end thereof; the rod-shaped portion being capable of being fitted into the receiving gap of the connecting seat member after the rear part is joined to the front part; the pressing block being forced to come into contact with the connecting seat member as soon as the lever is moved to such a position as to contact the pressing block at the pushing portion thereof after the rod-shaped portion has been fitted into the receiving gap, thus further securing the connecting seat member to the locating seat member; the pressing block being biased upwards and away from the connecting seat member by the second spring for allowing the rod-shaped portion to move out of the receiving gap as soon as the lever is moved to such a position as to contact the pressing block at the loosening portion thereof. 5. The frame of an electric cart as claimed in claimed 1, wherein the front part has a lifting handle pivoted thereto for allowing a person to lift the front part thereby. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frame of an electric cart for a person to ride on, more particularly one including a front part, and a rear part, which can be rapidly separated from the front part for the frame to occupy less space in storage and transportation, and which can be rapidly joined to the front part. 2. Brief Description of the Prior Art Electric carts are very convenient personal vehicles for physically handicapped people. Referring to FIG. 10, a conventional electric cart for a person to ride on includes a frame 8, front and rear wheels fitted to the frame 8, a handle bar, a seat, power and transmission (not shown) fitted on the frame 8. The frame 8 is made of several bars and rods, which are securely connected together by means of welding, therefore the frame can't be separated into several parts. Consequently, the electric cart will occupy much space in storage and transportation. SUMMARY OF THE INVENTION It is a main object of the present invention to provide a frame of an electric cart, which consists of a front part, and a rear part capable of being rapidly separated from and joined to the front part. The front part has a locating member secured on a rear end thereof, which is formed with a fitting portion. The rear part has a connecting member secured on a front end thereof for engaging the locating member of the front part, which connecting member has a spring-loaded engaging pin passed through it. The engaging pin will engage the fitting portion of the locating member automatically while the connecting member is being fitted onto the locating member, thus securely joining the rear part to the front part. And, the engaging pin will be disengaged from the fitting portion when it is pressed at a first end, thus allowing the rear part to be separated from the front part of the frame. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be better understood by referring to the accompanying drawings, wherein: FIG. 1 is a perspective view of the frame of an electric cart according to the present invention, FIG. 2 is an exploded perspective view of the connecting structure of the cart frame of the present invention, FIG. 3 is a vertical section of the connecting structure of the cart frame of the present invention, FIG. 4 is another vertical section of the connecting structure of the cart frame of the present invention, FIG. 5 is a view of the connecting structure of the present frame with the engaging pin being pressed, FIG. 6 is a partial side view of the present cart frame under disassembling action, FIG. 7 is a vertical section of the second embodiment, FIG. 8 is a vertical section of the second embodiment with the engaging pins being pressed, FIG. 9 is a partial perspective view of the front part of the cart frame of the present invention, and FIG. 10 is a perspective view of the conventional frame of an electric cart as described in Background. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 to 4, a preferred embodiment 1 of a frame of an electric cart for a person to ride on includes a front part 11, and a rear part 12. The front part 11 has a locating seat member 2 secured on a rear end thereof while the rear part 12 has a connecting seat member 5 secured on a front end thereof for separable connection with the locating seat member 2 of the front part 11. The locating seat member 2 has two spaced co-axial tube portions 24, and a fitting portion, which is formed with a through hole 21, a gap 22 adjacent to an upper portion of the through hole 21, and a slope 23 adjacent to and behind the gap 22; the gap 22 is narrower than the through hole 21. A pivotal rod 4, which has a radial through hole 41, is turnably passed into the co-axial tube portions 24 with the radial hole 41 being located between the co-axial tube portions 24. Furthermore, the locating seat member 2 is equipped with a fastening member 3, which includes a lever 31, a rod-shaped part 32, a pressing block 33, a spring 34, and a nut 35. The lever 31 is formed with a pushing portion 311, and a loosening portion 312 at a front end, and is pivotally connected to an upper end of the rod-shaped portion 32 at the front end. The rod-shaped part 32 is formed with screw threads on a lower end, and is passed through the pressing block 33, the spring 34, the radial through hole 41 of the pivotal rod 4 in sequence from the lower end, and connected to the nut 35 at the threaded lower end thereof. Thus, the fastening member 3 is fitted to the pivotal rod 4, which can turn on the locating seat member 2, while the pressing block 32 is biased towards the front end of the lever 31 by the spring 34. And, when the lever 31 is moved to such a position that the pushing portion 311 thereof contacts the pressing block 33, the pressing block 33 will be moved to a lowermost position. When the lever 31 is moved to such a position that the loosening portion 312 thereof contacts the pressing block 33, the pressing block 33 will be biased upwards and away from the lowermost position by the spring 34. The connecting seat member 5 has a top portion, two lateral wall portions 51, 52 projecting down from lateral edges of the top portion, and a receiving gap 53 on a front end of the top portion, which wall portions 51, 52 have co-axial through holes (not numbered) thereon. Furthermore, the connecting seat member 5 has an engaging pin 6 passed through the through holes of the wall portions 51 and 52. The engaging pin 6 is formed with a pressed end portion 61 at a first end, a thin portion 66 next to the pressed end portion 61, a cone-shaped portion 67 next to the thin portion 66, a stopped portion 64 next to the cone-shaped portion 67, and an insertion portion 62 at the other end, which is thinner than the stopped portion 64; the stopped portion 64 is wider than the gap 22 of the locating seat member 2, but it is slightly narrower than the through hole 21 of the locating seat member 2 while the thin portion 66 is narrower than the gap 22; the pressed end portion 61 is passed through the wall portion 51 while the insertion portion 62 is passed through a spring 63, and the wall portion 52 in sequence such that the spring 63 will bias the pin 6 in a direction away from the wall portion 52. In addition, a detaining element 65 is secured around an inner end of the pressed end portion 61 for preventing the engaging pin 6 from falling out of the connecting seat member 5; the detaining element 65 can be a ring-shaped one. In addition, the front part 11 has two extension portions 13 at lateral portions thereof, each of which is formed with a gap 131 at a rear end, while the rear part 12 is formed with two projections 14 on lateral sides thereof; to join the rear part 12 to the front part 11, the projections 14 are first fitted into respective ones of the gaps 131 of the extension portions 13 for the rear part 12 to be positioned in proper position as well as for allowing the rear part 12 to pivot on the rear ends of the extension portions 13. To connect the rear part 12 to the front part 11, referring to FIGS. 1 to 4, the rod-shaped part 32 of the fastening member 3 is laid down with the loosening portion 312 of the lever 31 facing it, and the rear part 12 is lifted at the front end, and the projections 14 are fitted into respective ones of the gaps 131 of the extension portions 13. Next, the rear part 12 is pivoted on the rear ends of the extension portions 13 such that the connecting seat member 5 is fitted over the locating seat member 2, and such that the engaging pin 6 is pressed against the slope 23 at the cone-shaped portion 67 thereof; during downward movement of the engaging pin 6 together with the seat member 5, the pin 6 will be made to move in such direction as to compress the spring 63 owing to contact of the cone-shaped portion 67 with the slope 23, and in turns, the engaging pin 6 is passed through the gap 22 of the locating seat member 2, and into the through hole 21 from the thin portion 66 thereof. Finally, the engaging pin 6 is moved by the spring 63 such that the stopped portion 64 is through the through hole 21; thus, the engaging pin 6 engages the locating seat member 2, and the connecting seat member 5 is stopped from separating from the locating seat member 2. Then, the fastening member 3 is upwards pivoted, and fitted into the receiving gap 53 of the connecting seat member 5 at the rod-shaped portion 32, and the lever 31 is pivoted to such a position as to press the pressing block 33 against the connecting seat member 5 at the pushing portion 311 thereof; thus, the seat members 2 and 5 are securely connected. Referring to FIGS. 3, 5 and 6, to separate the rear part 12 from the front part 11, first the lever 31 is pivoted to such a position as to face the pressing block 33 at the loosening portion 312 thereof, and the rod-shaped portion 32 is moved away from the receiving gap 53 of the connecting seat member 5. Next, the end portion 61 of the engaging pin 6 is pressed such that the stopped portion 64 is away from the through hole 21, and the thin portion 66 is in the through hole 21. Then, the rear part 12 is pivoted on the rear end of the extension portions 13 for the front end thereof to be lifted. Thus, both the engaging pin 6 and the connecting seat member 5 are moved away from the locating seat member 2, and the rear part 12 separated from the front part 11. Referring to FIG. 7, in a second embodiment, two engaging pins 6 are fitted to the connecting seat member 5 instead while the locating seat member 2 is formed with two fitting portions for connection with respective ones of the engaging pins 6, each of which fitting portions has a through hole 21, a gap 22, and a slope 23 like the fitting portion of the first embodiment. The engaging pins 6, 6 are passed through respective ones of the wall portions 51, 52 of the connecting seat member 5 at pressed end portions 61 thereof, and a spring 71 is connected to inner ends of the engaging pins 6, 6 at two ends thereof, and an axial rod 7 is passed through the spring 71, and movably passed into the engaging pins 6, 6 at two ends thereof. Detaining elements 65 are secured around inner ends of the pressed end portions 61 for preventing the pins 6, 6 from falling off. Thus, the engaging pins 6, 6 are biased away from each other by the spring 71. And, during downward movement of the engaging pins 6 together with the seat member 5 in connecting the rear part 12 to the front part 11, the pins 6 will be made to move in such direction as to compress the spring 71 owing to contact of cone-shaped portions 67, 67 thereof with the corresponding slopes 23, 23, and in turns, the engaging pins 6, 6 are passed through the gaps 22, 22 at thin portions 66, 66 thereof, and fitted in and engaged with the through holes 21, 21 at stopped portions 64, 64 thereof, as shown in FIG. 7. Consequently, the engaging pins 6, 6 will engage respective ones of the fitting portions of the locating seat member 2 after the connecting seat member 5 is fitted over the locating seat member 2. And, when the engaging pins 6, 6 are pressed at the pressed end portions 61, 61 thereof at the same time as shown in FIG. 8, the thin portions 66, 66 will be passed into the through holes 21, 21, and the engaging pins 6, 6 can be disengaged from the locating seat member 2; thus, the rear part 12 can be separated from the front part 11. Referring to FIGS. 1 and 9, the front part 11 of the frame further has two fitting tubes 15 secured thereto, and a lifting handle 16 is detachably connected and pivoted to the front part 11 by means of inserting two fitting end portions 161 of the lifting handle 16 into respective ones of the fitting tubes 15; thus, one can lift the front part 11 easily by the handle 16 after the rear part 12 has been separated from the front part 11. Referring to FIGS. 1 and 9 again, the fitting tubes 15 are further formed with connecting ears 151, and a strap 17 is connected to the connecting ears 151 at two ends thereof, and connected to a cover (not shown) of the cart frame 1 such that the frame cover is fastened to the frame 1. From the above description, it can be easily understood that the present invention has advantages as followings: 1. The connecting seat member 5 can be easily fitted to the locating seat member 2 therefore the rear part 12 can be rapidly joined to the front part 11. 2. Connection of the connecting seat member 5 with the locating seat member 2 can be secured with the help of the fastening member 3. 3. The rear part 12 can be lifted at the front end for separating the connecting seat member 5 from the locating seat member 2 after the engaging pin 6 is pressed. Therefore, the rear part 12 can be easily separated from the front part 11. 4. Because of the lifting handle 16 joined to the front part 11, a person can lift the front part 11 easily after the rear part 12 has been separated from the front part 11. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a frame of an electric cart for a person to ride on, more particularly one including a front part, and a rear part, which can be rapidly separated from the front part for the frame to occupy less space in storage and transportation, and which can be rapidly joined to the front part. 2. Brief Description of the Prior Art Electric carts are very convenient personal vehicles for physically handicapped people. Referring to FIG. 10 , a conventional electric cart for a person to ride on includes a frame 8 , front and rear wheels fitted to the frame 8 , a handle bar, a seat, power and transmission (not shown) fitted on the frame 8 . The frame 8 is made of several bars and rods, which are securely connected together by means of welding, therefore the frame can't be separated into several parts. Consequently, the electric cart will occupy much space in storage and transportation. | <SOH> SUMMARY OF THE INVENTION <EOH>It is a main object of the present invention to provide a frame of an electric cart, which consists of a front part, and a rear part capable of being rapidly separated from and joined to the front part. The front part has a locating member secured on a rear end thereof, which is formed with a fitting portion. The rear part has a connecting member secured on a front end thereof for engaging the locating member of the front part, which connecting member has a spring-loaded engaging pin passed through it. The engaging pin will engage the fitting portion of the locating member automatically while the connecting member is being fitted onto the locating member, thus securely joining the rear part to the front part. And, the engaging pin will be disengaged from the fitting portion when it is pressed at a first end, thus allowing the rear part to be separated from the front part of the frame. | 20040413 | 20060418 | 20051013 | 99596.0 | 0 | COLLADO, CYNTHIA FRANCISCA | STRUCTURE OF A FRAME OF AN ELECTRIC CART FOR A PERSON TO RIDE ON | SMALL | 0 | ACCEPTED | 2,004 |
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10,822,806 | ACCEPTED | Devices and methods for testing clock and data recovery devices | When used as a test data generator, CDR internal structures may be applied to generate drift conditions in the test data. For example, a finite state machine phase shifts a clock signal, over time, driving the test data generator thereby producing a drift condition on the test data. Once the test is completed, one of the other CDRs may be used as a tester to similarly generate test data for the first CDR. CDRs may be configured in pairs for this purpose so that one may be used to test the other. | 1. A method of testing a clock and data recovery device (CDR), comprising: producing test data from a first CDR; and testing another second CDR based on the test data from the first CDR. 2. The method of claim 1, further comprising: outputting the test data based on a clock; and generating data drift in the test data by changing a phase of the clock. 3. The method of claim 2, further comprising: setting the phase of the clock based on a count value; and changing the count value across a range of phase shifts. 4. The method of claim 3, further comprising: incrementing/decrementing the count value until a maximum/minimum count value is reached; subsequently decrementing/incrementing the count value until a minimum/maximum count value is reached; and repeating the above steps until all the test data is generated. 5. The method of claim 4, further comprising: adding one or more least significant bits to the counter value; incrementing/decrementing added least significant bits when incrementing/decrementing the counter value. 6. The method of claim 2, further comprising: generating test data results in the second CDR device; and verifying the test data results. 7. The method of claim 1, further comprising: producing test data from the second CDR; and testing the first CDR based on the test data from the second CDR. 8. A method of testing a plurality of clock and data recovery devices (CDRs), comprising: initializing one CDR to generate test data using a test data generator of the one CDR; initializing remaining CDRs to receive the test data; applying the test data to the remaining CDRs using the test data generator of the one CDR; and producing data drift in the test data by changing a phase of a clock that is applied to the test data generator. 9. A method of testing a plurality of clock and data recovery devices (CDRs), comprising: initializing a first CDR to generate a first test data using a first test data generator of the first CDR; initializing a second CDR to receive the first test data; applying the first test data to the second CDR using the first test data generator of the first CDR; producing a first data drift in the first test data by changing a phase of a first clock that is applied to the first test data generator; initializing the second CDR to generate a second test data using a second test data generator of the second CDR, if a test of the second CDR is completed; initializing the first CDR to receive the second test data; applying the second test data to the first CDR using the second test data generator of the second CDR; and producing a second data drift in the second test data by changing a phase of a second clock that is applied to the second test data generator. 10. A clock and data recovery device (CDR) device, comprising: a phase variable clock source to generate a phase variable clock; a test data generator to generate test data based on the phase variable clock; a counter that has a count value to control a phase of the phase variable clock; and a finite state machine to increment/decrement the count value. 11. The CDR of claim 10, wherein the finite state machine increments/decrements the count value until a maximum/minimum count value is reached, and subsequently decrements/increments the count value until a minimum/maximum count value is reached, wherein the finite machine increments/decrements the count value until all the test data is generated. 12. The CDR of claim 11, wherein: the counter includes one or more least significant bits added to the counter value, the counter without the least significant bits are used to control the phase of the phase variable clock; and the finite state machine increments/decrements the least significant value bits when incrementing/decrementing the counter value. 13. The CDR of claim 10, wherein the test data generator is a pseudo random number generator. 14. The CDR of claim 10, wherein the phase variable clock source is a phase rotator coupled to a phase locked loop (PLL) oscillator. 15. A system or a network implementing the CDR of claim 10. 16. A clock and data recovery device (CDR) device to test another second CDR, comprising: means for generating test data to test the second CDR; and means for producing a range of data drift conditions in the test data. 17. The CDR of claim 16, wherein means for producing a range of data drift conditions include means for reducing a rate of data drift. 18. An apparatus including a plurality of clock and data recovery devices, comprising: a first CDR having a test data generator; and another second CDR, wherein the first CDR uses the test data generator to generate test data to test the second CDR. 19. The apparatus of claim 18, further comprising: the first CDR having a finite state machine to adjust data drift in the test data. 20. The apparatus of claim 18, further comprising: the second CDR having a data checker to check a test data result output. | BACKGROUND OF THE INVENTION 1. Field of Invention The present invention relates to testing clock and data recovery devices. 2. Description of Related Art A clock and data recovery device is normally used in transmission and reception of serial data stream that does not transmit a clock signal. Instead, the clock signal is derived from the serial data stream itself. SUMMARY OF THE INVENTION While clock and data recovery devices (CDRs) may be tested using data generated by pseudo random number generators or multiple test vectors, there is a need to test CDRs at optimal rates that includes coverage of data drift conditions. This invention provides a CDR that generates test data that incorporates data drift conditions for testing other CDRs. Data drift conditions may be generated by enhancing CDR internal components. For example, a finite state machine may be introduced to cause a shift in the clock signal that drives a test data generator to produce the data drift conditions. When multiple CDRs are configured together, the CDRs may be used to test each other. A first CDR may be selected to test other CDRs. Once the test is completed, another CDR may be used to test the first CDR. CDRs may be configured in pairs for this purpose so that one may be used to test the other. BRIEF DESCRIPTION OF THE DRAWINGS Various exemplary embodiments of the invention are described in detail with reference to the following figures wherein: FIG. 1 illustrates an exemplary functional block diagram of a data transmit/receive system; FIG. 2 illustrates a detailed exemplary functional block diagram of a CDR; FIGS. 3 and 4 illustrate relative timing relationships between recovered clock and edge transitions of a serial data stream; FIG. 5 illustrates an exemplary diagram of a finite state machine; FIG. 6 is an exemplary block diagram of the CDR of FIG. 2 testing another CDR; and FIGS. 7-9B are flowcharts illustrating exemplary test processes. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS This invention enables a plurality of CDRs to test each other. For a two CDR configuration, during a first phase, a first CDR is used to test a second CDR. During a second phase, the role is reversed, and the second CDR is used to test the first CDR. For ease of understanding, CDR clock and data recovery functions are first discussed, and then test data generation functions are discussed. FIG. 1 is an exemplary functional block diagram of a data transmit/receive system 10 that includes CDRs 40 and 50 in transceivers 20 and 30, respectively. The data transmit/receive system 10 is representative of various communication systems and networks, computer systems and networks, etc. Only one CDR 40 and 50 is shown in each of the transceivers 20 and 30 to simplify discussion. The transceivers 20 and 30 receive serial data streams using the receiver modules 22 and 32, respectively, and transmit serial data streams using transmitter modules 24 and 34, respectively. The CDRs 40 and 50 retrieve data bits from the respective serial data streams, without requiring a transmitted clock signal. The CDRs 40 and 50 generate a recovered clock based on the respective serial data streams, and the recovered clock is used to recover individual data bits in the respective serial data streams. Typically, data drift conditions exist which result in the serial data streams drifting in phase during transmission. The CDRs 40 and 50 include logic to track such drift conditions. FIG. 2 is an exemplary block diagram of the CDR 40, which may be the same as the CDR 50. The CDR 40 includes a controller 41, a phase locked loop clock generator (PLL) 42, phase rotators 441 and 442, a sampler 46, a serial to parallel converter 47, a comparator 48, a counter 54, a test data generator 56, a decoder 57 and an additional finite state machine 58 for test purposes. The test data generator 56 may be a pseudo random number generator, a fixed value stored in a register, any finite state machine, etc. The CDR 40 uses these modules to perform clock and data recovery operation as well as test data generation operations. The controller 41 receives comparator signals from the comparator 48 and causes the counter 54 to adjust its value at the appropriate time. Referring to FIG. 6, the PLL 42 generates N clock signals at the frequency of operation for the CDRs 40 and 40′ locked on the PLL clock and delayed from each other by the period over N. The N clocks are phase shifted together by the phase rotators 441 and 442 (44′1 and 44′2) to generate N sampling clocks. Two phase rotators 441 and 442 (44′1 and 44′2) are shown generating the sampling clocks Clk0 . . . Clk3 (Clk0′ . . . Clk3′) which are at ¼ clock cycle apart based on the PLL delay elements. The phase rotators 441 and 442 may share common control signals such that the sampling clocks Clk0 . . . Clk3 are controlled to be always a fixed phase apart (e.g. 90 degree or π/2 apart), for example. Referring back to FIG. 2, the sampler 46 receives the sampling clocks Clk0 . . . Clk3 and samples the serial data stream to generate sampled data bits. The comparator 48 determines edge transitions of the serial data stream based the sampled data bits. Based on the edge transitions, the comparator 48 generates “up”, “down” or “no change” signals. The comparator signals are sent to the controller 41 and the sampled data bits are sent with the recovered clock to the serial to parallel converter 47 for parallel conversion. The controller 41 uses the comparator signals to generate control signals that adjust a counter value of the counter 54. The decoder 57 receives the adjusted counter value and generates a phase rotator control signal that causes the phase rotators 441 and 442 to phase shift the sampling clocks Clk0 . . . Clk3 and thereby compensate for the data drift conditions. During data recovery, edge transitions are constantly monitored, to detect for data drift. Depending on where the edge transition lies, the comparator 48 outputs one of three signals, “up”, “down” or “no change.” When an “up” signal is received, the controller 41 causes the counter 54 to increment its counter value. The decoder 57 receives the incremented counter value and causes the phase rotators 441 and 442 to shift the phase of the sampling clocks Clk0 . . . Clk3 to the left (phase lead) by one phase increment. The “down” signal causes the counter 54 to decrement which causes the phase rotators 441 and 442 to shift right (phase lag) by one phase increment. The “no change” signal does not modify the value of the counter 54. FIGS. 3 and 4 illustrate possible relationships among the recovered clock, the sampling points 0 . . . 3 and the serial data stream. Referring to FIG. 3, on the left side, the edge transition 94 lies between the sampling points 0 and 1. In this case, a rising edge 72 of the recovered clock is “phase leading” the edge transition 94 because rising edge 72 occurs before the edge transition 94. This condition indicates that the data is drifting behind the recovered clock. Thus, to compensate for this data drift, the comparator 48 sends a “down” signal which eventually causes the phase rotators 441 and 442 to apply a “phase lag” to the sampling clocks Clk0 . . . Clk3. As shown on the right side of FIG. 3, the phase difference between the rising edge 72 and the edge transition 94 has been reduced at a later time reducing the data drift between the recovered clock and the serial data stream. This update of the sampling position is made “smooth” to follow the slow data drift while the high frequency jitter is filtered. For example, the high frequency jitter filter and the number of clock cycles used by the controller 41 may be designed in compliance with known telecommunication or computer standards. Referring now to FIG. 4, on the left side, the edge transition 94 lies between the sampling points 3 and 0. In this case, a rising edge 72 of the recovered clock is “phase lagging” the edge transition 94 because rising edge 72 occurs after the edge transition 94. This condition indicates that the data is drifting ahead of the recovered clock. To compensate for this data drift, the comparator 48 sends an “up” signal that eventually increments the counter 54 to cause the phase rotators 441 and 442 to apply a “phase lead” to the clocks Clk0 . . . Clk3. As shown on the right side of FIG. 4, the phase difference between the edge transition 94 and the rising edge 72 has been reduced at a later time reducing the data drift between the recovered clock and the serial data stream. Based on the above summary of the CDR data retrieval operation, CDR functioning as a test data generator is discussed below. Referring back to FIG. 2, when the CDR 40 operates as a tester, the sampler 46, the serial to parallel converter 47 and the comparator 48 are not used. The test data generator 56, the finite state machine 58, the counter 54 and the phase rotators 441 and 442 are used to generate test data having data drift conditions. The sampling clocks Clk0 . . . Clk3 are coupled to the test data generator clock so that the generated test data changes phase based on the value of the counter 54. The finite state machine 58 controls incrementing or decrementing the counter 54 to ensure that a full range of data drift conditions is generated. At the start of a test sequence, the CDR 40 may be initialized as a test data generator by setting the counter 54 to receive increment/decrement signals from the finite state machine 58 instead of the regular increment/decrement signals from the controller 41 and enable test data output from the test data generator 56. The counter 54 may be initialized to any value. For the discussion below, the counter 54 is assumed to be initialized to 0 and the finite state machine 58 is initialized to a Min state. Also, to control the rate of test data drifts to be below the threshold data drift rate, additional bits 55 may be appended to the least significant end of the counter 54. In this example, two bits are appended to reduce the data drift rate to be less than the threshold rate. FIG. 5 shows an exemplary finite state machine 120 having two states Min and Max. Other implementations are also possible to perform the same functions. For example, a four states finite state machine may be implemented. During the first state, the finite state machine initializes the counter 54 such that the test data generator 56 sends test data without data drift to the CDR 40′. During the second state, the finite state machine periodically increments the counter value that causes the phase rotators 441 and 442 to progressively apply a positive drift to the test data until a maximum counter value is reached. Then, during the third state, the finite state machine periodically decrements the counter value that causes the phase rotators 441 and 442 to progressively apply a negative drift to the test data until a minimum counter value is reached. Then, during the fourth state, the finite state machine provides a test data generator 56 rest period in which a data checker 62′ can check the results of the test data. Referring now to FIG. 5, after initialization, the finite state machine 120 increments the counter 54 every 16 cycles in the exemplary implementation, i.e., 16 clock cycles correspond to one cycle of the controller 41. Due to the two additional bits, the counter value used by the phase rotators 441 and 442 is incremented every four times the 16 clock cycles, which is slow enough to be followed by the CDR 40′ under test. This continues until a max counter value is reached. At the next clock cycle, the finite state machine 120 transitions to the Max state and decrements the counter 54 (i.e., decrements the appended least significant bits). This continues until a minimum counter value (0) is reached. At the next clock cycle, the finite state machine 120 changes to the Min state and increments the counter 54. Thus, by the above process, the test data drift is changed from 0 degree to 360 degrees and then downwards to 0 degree, and so on until all the test data is generated. By adjusting the counter value, the finite state machine 58 controls the counter 54 to cause the phase rotators 441 and 442 to phase shift the sampling clocks Clk0 . . . Clk3 left or right which in turn causes the test data to drift in corresponding directions. FIG. 6 is an exemplary block diagram of the CDR 40 testing another CDR 40′. The CDR 40′ may have similar components as the CDR 40 or it may be a CDR without the test data generation components. As described above, the CDRs 40 and 40′ use a common PLL 42 clock. Sampling clock signals Clk0 . . . Clk3 and Clk0′ . . . . Clk3′ are generated by the respective phase rotators 441 and 442, and 44′1 and 44′2. The phase rotators 441 and 442, and 44′1 and 44′2 operate independently from each other based on the counter value of the respective counters 54 and 54′. The output of the test data generator 56 of the CDR 40 is coupled to the input of the sampler 46′ of the CDR 40′ via its input data port. The CDR 40′ receives test data that is progressively phase shifted from min to max degrees (e.g., from 0 degree to 360 degrees and back to 0 degree). Thus, generating test data simulates a full data drift range thereby forcing the phase rotators 44′1 and 44′2 to traverse across the full range of data drift conditions. Accordingly, if the recovered data output by the CDR 40′ is correct, then the CDR 40′ is operating properly. The data checker 62′ may be used to check the test data results. If a signature generator is included in the CDR 40′, then the checker 62′ may compare the signature to an expected value. Otherwise, the checker 62′ verifies that all the recovered data is correct. FIG. 7 is a flowchart illustrating an exemplary test process. It should be appreciated that multiple CDRs may be involved in the test. In one case, the CDRs are configured in pairs so that one may test the other. Stated differently, within a pair, a first CDR is configured as a test data generator to test a second CDR. Once the test is completed, the second CDR is configured as a test data generator to test the first CDR. In another case, one CDR may be configured as a test data generator to test the remaining CDRs. It should be appreciated that any test configuration method may be used to achieve a desired result. Referring now to FIG. 7, the exemplary test process starts with a test machine sending appropriate control signals to the CDRs to place them in test mode. At step S100, at least one CDR 40 is initialized for generating test data. As discussed above, the sampler 46, the serial to parallel converter 47 and the comparator 48 are not used when in the test data generator mode. The test machine may select the finite state machine 58 to increment/decrement the counter 54, and initialize the counter 54 to a default counter value, such as “0” such that no data drift is applied to the test data initially. In other cases, the CDR 40 itself may have internal mechanisms that select the finite state machine 58 and initialize the counter 54. As noted above, the output of the finite state machine 58 increments/decrements added least significant bits (LSBs) of the counter 54 to control the test data drift rate. Then, at step S102, at least one CDR 40′ to be tested is initialized to receive test data. The CDR 40′ may have its data checker 62′ initialized to receive and check test data. After initialization is complete, the process goes to an optional step S104 where a test register of the data checker 62′ of the CDR 40′ is tested for faults. For example, the test machine, using conventional techniques, detects whether one or more bits of the test register are stuck at logic value “high” or “low”. If the test machine detects such fault, then the test process continues to step S106 where the test machine registers the CDR 40′ as “fail” and ends the test process. Otherwise, the test process continues to step S108. At step S108, the test machine may activate the test data generator 56 to generate and output test data points at every clock cycle. In other cases, the CDR 40's internal mechanisms, such as the finite state machine 58, may activate the test data generator. It should be appreciated that the test data generator 56 continuously generates test data points throughout the test process until step S118 is reached. The test process then goes to step S110. At step S110, the finite state machine 58 increments the counter 54 (which now includes the two added LSBs). It should be appreciated that due to the added LSBs, it takes the counter 54 four times as long to cause the phase rotators 441 and 442 to phase shift the sampling clocks Clk0 . . . . Clk3 by one phase increment. The test process goes to step S112. At step S112, the finite state machine 58 determines if the counter value equals to a max value. If not equal to the max value, then the test process returns to step S110; otherwise the process goes to step S114. At step S114, the counter is decremented and the test process goes to step S116. At step S116, the finite state machine 58 determines if the counter value equals to a min value. If not equal to the min value, then the test process returns to step S114; otherwise, the test process goes to step S118. At step S118, the test machine causes the test data generator 56 to stop generating test data points. Or, the CDR 40's internal mechanisms may stop the operation of the test data generator 56. Then, at step S120, the test machine checks the test register of the data checker 62′ to verify the test data results for correctness. The test process then continues to step S122, where the test process ends. FIG. 8 is a flowchart illustrating an exemplary test process where one CDR is used as a test data generator for remaining CDRs. The exemplary test process starts at step S200 with the test machine sending appropriate control signals which may initialize one CDR as a test data generator. Then, at step S202, the test machine may initialize remaining CDRs to receive test data. The initialization process may be similar to that described above with respect to FIG. 7. After initialization is complete, the test process goes to an optional step S204 where the test machine checks the test registers of the data checkers of the CDRs to be tested. For example, the test machine determines whether one or more test registers have one or more bits that are stuck at logic value “high” or “low”. If so, then the test process continues to step S206 where the test process ends. There are cases where the test machine marks the CDRs with stuck bits to be defective. Only after a predetermined number of defective CDRs are marked will the test process go to step S206 where the test process ends. Otherwise, the test process continues to step S208. At step S208, the test machine may activate the CDR functioning as a test data generator to continuously generate test data. Or, as discussed above, in some cases the CDR's internal mechanisms may activate the test data generator. Then, at step S210, the remaining CDRs are tested under data drift conditions. This portion of the test process may be similar to the test process steps S110 to S116 described with respect to FIG. 7. Then, at step S212, the test machine, or in some cases, the CDR's internal mechanisms, may cause the test data generator to stop generating test data points. The test process goes to step S214 where the test machine checks the test registers of the data checkers to verify the test data results for correctness. The test process then continues to step S216, where the test process ends. FIG. 9 is a flowchart illustrating an exemplary test process where the CDRs are configured in pairs so that one may test the other and vice versa. Plural CDRs are paired and for simplicity of description, one of the CDRs in the pair will be referred to as an “odd” CDR and the other CDR will be referred to as an “even” CDR. The exemplary test process starts at step S300 where the test machine sends appropriate control signals which may initialize the odd CDRs as test data generators. Then, at step S302, the test machine may initialize the even CDRs to receive test data. After initialization is complete, the test process goes to an optional step S304 where the test machine checks the test registers of the even CDRs. If one or more test registers have one or more bits that are stuck at logic value “high” or “low”, then the test process goes to step S306 where the test process ends. Otherwise, the test process continues to step S308. At step S308, the test machine or the odd CDRs' internal mechanisms may activate the odd CDRs to function as test data generators. Then, at step S310, the even CDRs are tested under data drift conditions. This portion of the test process may be similar to the test process steps S110 to S116 described with respect to FIG. 7. Then, at step S312, the test machine or the odd CDRs' internal mechanisms may cause the odd CDRs to stop generating test data points. At step S313, the test machine checks the test registers of the even CDRs to verify the test data results for correctness. If a predetermined number of test registers output erroneous data results the test process goes to step S314 where the test process ends. Otherwise, the test process continues to step S316. At step S316, the test machine may initialze the even CDRs to function as test data generators. Then, at step S318, the test machine may initialize the odd CDRs to receive test data. The test process then continues to an optional step S320. At step S320, the test machine checks the test registers of the odd CDRs. If a predetermined number of test registers have one or more bits that are stuck at logic value “high” or “low”, then the test process goes to step S322 where the test process ends. Otherwise, the test process continues to step S324. At step S324, the test machine or the even CDRs' internal mechanisms may activate the even CDRs to function as test data generators. Then, at step S326, the odd CDRs are tested under data drift conditions. This portion of the test process may be similar to the test process steps S110 to S116 described with respect to FIG. 7. Then, at step S328, the test machine or the even CDRs' internal mechanisms may cause the even CDRs to stop generating test data points. At step S330, the test machine checks the test registers of the odd CDRs to verify the test data results for correctness. The test process then continues to step S332, where the test process ends. It should be appreciated that although references are made to PLLs, this should not be construed as limiting the scope of the invention. For example, Delay Locked Loops (DLLs), etc., may be used. It should be appreciated that the exemplary modules described above can be various semiconductor devices such as ASICs or other integrated circuits, a discrete element circuit, a programmable logic device such as a PLD, PLA, FPGA or PAL, or the like. The particular form that the CDRs have is a design choice and would be apparent to those skilled in the art. While this invention has been described in conjunction with the exemplary embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the exemplary embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of Invention The present invention relates to testing clock and data recovery devices. 2. Description of Related Art A clock and data recovery device is normally used in transmission and reception of serial data stream that does not transmit a clock signal. Instead, the clock signal is derived from the serial data stream itself. | <SOH> SUMMARY OF THE INVENTION <EOH>While clock and data recovery devices (CDRs) may be tested using data generated by pseudo random number generators or multiple test vectors, there is a need to test CDRs at optimal rates that includes coverage of data drift conditions. This invention provides a CDR that generates test data that incorporates data drift conditions for testing other CDRs. Data drift conditions may be generated by enhancing CDR internal components. For example, a finite state machine may be introduced to cause a shift in the clock signal that drives a test data generator to produce the data drift conditions. When multiple CDRs are configured together, the CDRs may be used to test each other. A first CDR may be selected to test other CDRs. Once the test is completed, another CDR may be used to test the first CDR. CDRs may be configured in pairs for this purpose so that one may be used to test the other. | 20040413 | 20080520 | 20051013 | 74692.0 | 0 | BHAT, ADITYA S | DEVICES AND METHODS FOR TESTING CLOCK AND DATA RECOVERY DEVICES | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,822,933 | ACCEPTED | Loaded antenna | A novel loaded antenna is defined in the present invention. The radiating element of the loaded antenna consists of two different parts: a conducting surface and a loading structure. By means of this configuration, the antenna provides a small and multiband performance, and hence it features a similar behaviour through different frequency bands. | 1. A loaded antenna characterized in that a radiating element of the antenna includes at least two parts, a first part consisting of at least one conducting surface, a second part being a loading structure, said loading structure including at least a conducting strip, wherein at least one of said strips are connected at least at one point on the edge of said first conducting surface, and wherein the maximum width of said strip or strips is smaller than a quarter of the longest edge of first conducting surface. 2. A loaded antenna according to claim 1, wherein two tips of at least one of the conducting strips are connected at two points on the perimeter of said first conducting surface. 3. A loaded antenna according to claim 1 or 2 wherein said first conducting surface and second loading structure are lying on a common flat or curved surface. 4. A loaded antenna according to claim 1 comprising a conducting surface and at least a first and a second strip, wherein said first strip is connected at least at one point on the perimeter of said conducting surface, and wherein said second strip is connected at least by means of one of its tips to said first conducting strip. 5. A loaded antenna according to claim 1 wherein the antenna includes at least a second conducting surface, said second conducting surface featuring a smaller area than the first conducting surface, and wherein at least one conducting strip is connected to the first conducting surface at one end, and to the second conducting surface at another end 6. A loaded antenna including a conducting surface and a loading structure according to claim 1, wherein the perimeter of said conducting surface is shaped as either a triangle, a square, a rectangle, a trapezoid, a pentagon, a hexagon, a heptagon, an octagon, a circle or an ellipse. 7. A loaded antenna including a conducting surface and a loading structure according to claim 1, wherein at least a portion of said conducting surface is a multilevel structure. 8. A loaded antenna including a conducting surface and a loading structure according to claim 1, wherein the shape of at least one loading strip is a curve that includes a minimum of two segments and a maximum of nine segments which are connected in such a way that each segment forms an angle with an adjacent segment such that, no pair of adjacent segments define a larger straight segment. 9. A loaded antenna including a conducting surface and a loading structure according to claim 1, wherein the loading structure includes at least one straight strip, said straight strip having one end connected to a point on an edge of said conducting surface. 10. A loaded antenna including a conducting surface and a loading structure according to claim 1, wherein at least one loading strip is shaped as a space-filling curve. 11. A loaded antenna including a conducting surface and a loading structure according to claim 1, wherein at least one loading strip is a straight strip with a polygonal shape. 12. A loaded antenna including a conducting surface and a loading structure according to claim 1, wherein the loading structure includes at least two strips, and wherein a tip of a first one of the strips is free of connection. 13. A loaded antenna including a conducting surface and a loading structure according to claim 1 wherein the loading structure includes two or more strips connected at several points on a perimeter of said conducting surface. 14. (canceled) 15. A loaded antenna including a conducting surface and a loading structure according to claim 1, wherein a central portion of the conducting surface is removed. 16. A loaded antenna according to claim 1, wherein the antenna is a monopole, said monopole including a ground-plane or ground-counterpoise and a radiating element, said radiating element including at least a conducting surface and a loading structure. 17. A loaded antenna according to claim 1, wherein the antenna is a dipole including two arms, said arms including at least a conducting surface and a loading structure. 18. A loaded antenna according to claims 16 or 17 where the radiating element is printed on one side of a dielectric substrate and the load has a conducting surface on another side of the substrate. 19. A loaded antenna according to claim 1, wherein the antenna is a microstrip patch antenna and wherein a radiating patch of said antenna includes a conducting surface and a loading structure. 20. A loaded antenna according to claim 1, characterized in that the antenna features a multiband behavior, a broadband behavior or a combination of a multiband behavior and a broadband behavior. 21. A loaded antenna according to claim 1, characterized in that the antenna is shorter than a quarter of the central operating wavelength. 22. (canceled) 23. A loaded antenna according to claim 1, characterized in that the radiating element is used in at least one of the selective elements on a frequency selective surface. 24. A loaded antenna according to claim 1, characterized in that the geometry of the surface, the loading structure or both are shaped by an iterated function system mathematical algorithm, a multi-reduction copy machine mathematical algorithm, a networked multi-reduction copy machine mathematical algorithm, or a combination thereof. 25. A loaded antenna including a conducting surface and a loading structure according to claim 1, wherein the loading structure includes at least two strips, and wherein a tip of a first one of the strips is connected to a second one of the strips. 26. A loaded antenna including a conducting surface and a loading structure according to claim 1, wherein the loading structure includes at least two strips, and wherein both tips of a first one of the strips are connected to a second one or the strips. 27. A loaded antenna including a conducting surface and a loading structure according to claim 1, wherein the loading structure includes at least two strips, and wherein a first tip of a first one of the strips is connected to a second one of the strips and a second tip of the first one of the strips is connected to the conducting surface. | OBJECT OF THE INVENTION The present invention relates to a novel loaded antenna which operates simultaneously at several bands and featuring a smaller size with respect to prior art antennas. The radiating element of the novel loaded antenna consists on two different parts: a conducting surface with a polygonal, space-filling or multilevel shape; and a loading structure consisting on a set of strips connected to said first conducting surface. The invention refers to a new type of loaded antenna which is mainly suitable for mobile communications or in general to any other application where the integration of telecom systems or applications in a single small antenna is important. BACKGROUND OF THE INVENTION The growth of the telecommunication sector, and in particular, the expansion of personal mobile communication systems are driving the engineering efforts to develop multiservice (multifrequency) and compact systems which require multifrequency and small antennas. Therefore, the use of a multisystem small antenna with a multiband and/or wideband performance, which provides coverage of the maximum number of services, is nowadays of notable interest since it permits telecom operators to reduce their costs and to minimize the environmental impact. Most of the multiband reported antenna solutions use one or more radiators or branches for each band or service. An example is found in U.S. patent Ser. No. 09/129,176 entitled “Multiple band, multiple branch antenna for mobile phone”. One of the alternatives which can be of special interest when looking for antennas with a multiband and/or small size performance are multilevel antennas, Patent publication WO01/22528 entitled “Multilevel Antennas”, and miniature space-filling antennas, Patent publication WO01/54225 entitled “Space-filling miniature antennas”. In particular in the publication WO 01/22528 a multilevel antennae was characterised by a geometry comprising polygons or polyhedrons of the same class (same number of sides of faces), which are electromagnetically coupled and grouped to form a larger structure. In a multilevel geometry most of these elements are clearly visible as their arwea of contact, intersection or interconnection (if these exists) with other elements is always less than 50% of their perimeter or area in at least 75% of the polygons or polyhedrons. In the publication WO 01/54225 a space-filling miniature antenna was defined as an antenna havinf at least one part shaped as a space-filling-curve (SFC), being defined said SFC as a curve composed by at least ten connected straight segments, wherein said segments are smaller than a tenth of the operating free-space wave length and they are spacially arranged in such a way that none of said adjacent and connected segments from another longer straight segment. The international publication WO 97/06578 entitled fractal antennas, resonators and loading elements, describe fractal-shaped elements which may be used to form an antenna. A variety of techniques used to reduce the size of the antennas can be found in the prior art. In 1886, there was the first example of a loaded antenna; that was, the loaded dipole which Hertz built to validate Maxwell equations. A. G. Kandoian (A. G. Kandoian, Three new antenna types and their applications, Proc. IRE, vol. 34, pp. 70W-75W, February 1946) introduced the concept of loaded antennas and demonstrated how the length of a quarter wavelength monopole can be reduced by adding a conductive disk at the top of the radiator. Subsequently, Goubau presented an antenna structure top-loaded with several capacitive disks interconnected by inductive elements which provided a smaller size with a broader bandwith, as is illustrated in U.S. Pat. No. 3,967,276 entitled “Antenna structures having reactance at free end”. More recently, U.S. Pat. No. 5,847,682 entitled “Top loaded triangular printed antenna” discloses a triangular-shaped printed antenna with its top connected to a rectangular strip. The antenna features a low-profile and broadband performance. However, none of these antenna configurations provide a multiband behaviour. In Patent No. WO0122528 entitled “Multilevel Antennas”, another patent of the present inventors, there is a particular case of a top-loaded antenna with an inductive loop, which was used to miniaturize an antenna for a dual frequency operation. Also, W. Dou and W. Y. M. Chia (W. Dou and W. Y. M. Chia, “Small broadband stacked planar monopole”, Microwave and Optical Technology Letters, vol. 27, pp. 288-289, November 2000) presented another particular antecedent of a top-loaded antenna with a broadband behavior. The antenna was a rectangular monopole top-loaded with one rectangular arm connected at each of the tips of the rectangular shape. The width of each of the rectangular arms is on the order of the width of the fed element, which is not the case of the present invention. SUMMARY OF THE INVENTION The key point of the present invention is the shape of the radiating element of the antenna, which consists on two main parts: a conducting surface and a loading structure. Said conducting surface has a polygonal, space-filling or multilevel shape and the loading structure consists on a conducting strip or set of strips connected to said conducting surface. According to the present invention, at least one loading strip must be directly connected at least at one point on the perimeter of said conducting surface. Also, circular or elliptical shapes are included in the set of possible geometries of said conducting surfaces since they can be considered polygonal structures with a large number of sides. Due to the addition of the loading structure, the antenna can feature a small and multiband, and sometimes a multiband and wideband, performance. Moreover, the multiband properties of the loaded antenna (number of bands, spacing between bands, matching levels, etc) can be adjusted by modifying the geometry of the load and/or the conducting surface. This novel loaded antenna allows to obtain a multifrequency performance, obtaining similar radioelectric parameters at several bands. The loading structure can consist for instance on a single conducting strip. In this particular case, said loading strip must have one of its two ends connected to a point on the perimeter of the conducting surface (i.e., the vertices or edges). The other tip of said strip is left free in some embodiments while, in other embodiments it is also connected at a point on the perimeter of said conducting surface. The loading structure can include not only a single strip but also a plurality of loading strips located at different locations along its perimeter. The geometries of the loads that can be connected to the conducting surface according to the present invention are: a) A curve composed by a minimum of two segments and a maximum of nine segments which are connected in such a way that each segment forms an angle with their neighbours, i.e., no pair of adjacent segments define a larger straight segment. b) A straight segment or strip c) A straight strip with a polygonal shape d) A space-filling curve, Patent No. PCT/ES00/00411 entitled “Space-filling miniature antennas”. In some embodiments, the loading structure described above is connected to the conducting surface while in other embodiments, the tips of a plurality of the loading strips are connected to other strips. In those embodiments where a new loading strip is added to the previous one, said additional load can either have one tip free of connection, or said tip connected to the previous loading strip, or both tips connected to previous strip or one tip connected to previous strip and the other tip connected to the conducting surface. There are three types of geometries that can be used for the conducting surface according to the present invention: a) A polygon (i.e., a triangle, square, trapezoid, pentagon, hexagon, etc. or even a circle or ellipse as a particular case of polygon with a very large number of edges). b) A multilevel structure, Patent No. WO0122528 entitled “Multilevel Antennas”. c) A solid surface with an space-filling perimeter. In some embodiments, a central portion of said conducting surface is even removed to further reduce the size of the antenna. Also, it is clear to those skilled in the art that the multilevel or space-filling designs in configurations b) and c) can be used to approximate, for instance, ideal fractal shapes. FIG. 1 and FIG. 2 show some examples of the radiating element for a loaded antenna according to the present invention. In drawings 1 to 3 the conducting surface is a trapezoid while in drawings 4 to 7 said surface is a triangle. It can be seen that in these cases, the conducting surface is loaded using different strips with different lengths, orientations and locations around the perimeter of the trapezoid, FIG. 1. Besides, in these examples the load can have either one or both of its ends connected to the conducting surface, FIG. 2. The main advantage of this novel loaded antenna is two-folded: The antenna features a multiband or wideband performance, or a combination of both. Given the physical size of radiating element, said antenna can be operated at a lower frequency than most of the prior art antennas. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a trapezoid antenna loaded in three different ways using the same structure; in particular, a straight strip. In case 1, one straight strip, the loading structure (1a) and (1b), is added at each of the tips of the trapezoid, the conducting surface (1c). Case 2 is the same as case 1, but using strips with a smaller length and located at a different position around the perimeter of the conducting surface. Case 3, is a more general case where several strips are added to two different locations on the conducting surface. Drawing 4 shows a example of a non-symmetric loaded structure and drawing 5 shows an element where just one slanted strip has been added at the top of the conducting surface. Finally, cases 6 and 7 are examples of geometries loaded with a strip with a triangular and rectangular shape and with different orientations. In these cases, the loads have only one of their ends connected to the conducting surface. FIG. 2 shows a different particular configuration where the loads are curves which are composed by a maximum of nine segments in such a way that each segment forms an angle with their neighbours, as it has been mentioned before. Moreover, in drawings 8 to 12 the loads have both of their ends connected to the conducting surface. Drawings 8 and 9, are two examples where the conducting surface is side-loaded. Cases 13 and 14, are two cases where a rectangle is top-loaded with an open-ended curve, shaped as is mentioned before, with the connection made through one of the tips of the rectangle. The maximum width of the loading strips is smaller than a quarter of the longest edge of the conducting surface. FIG. 3 shows a square structure top-loaded with three different space-filling curves. The curve used to load the square geometry, case 16, is the well-known Hilbert curve. FIG. 4 shows three examples of the top-loaded antenna, where the load consist of two different loads that are added to the conducting surface. In drawing 19, a first load, built with three segments, is added to the trapezoid and then a second load is added to the first one. FIG. 5 includes some examples of the loaded antenna where a central portion of the conducting surface is even removed to further reduce the size of the antenna. FIG. 6 shows the same loaded antenna described in FIG. 1, but in this case as the conducting surface a multilevel structure is used. FIG. 7 shows another example of the loaded antenna, similar to those described in FIG. 2. In this case, the conducting surface consist of a multilevel structure. Drawings 31,32, 34 and 35 use different shapes for the loading but in all cases the load has both ends connected to the conducting surface. Case 33 is an example of an open-ended load added to a multilevel conducting surface. FIG. 8 presents some examples of the loaded antenna, similar to those depicted in FIGS. 3 and 4, but using a multilevel structure as the conducting surface. Illustrations 36, 37 and 38, include a space-filling top-loading curve, while the rest of the drawings show three examples of the top-loaded antenna with several levels of loadings. Drawing 40 is an example where three loads have been added to the multilevel structure. More precisely, the conducting surface is firstly loaded with curve (40a), next with curves (40b) and (40c). Curve (40a) has both ends connected to conducting surface, curve (40b) has both ends connected to the previous load (40a), and load (40c), formed with two segments, has one end connected to load (40a) and the other to the load (40b). FIG. 9 shows three cases where the same multilevel structure, with the central portions of the conducting surface removed, which is loaded with three different type of loads; those are, a space-filling curve, a curve with a minimum of two segments and a maximum of nine segments connected in such a way mentioned just before, and finally a load with two similar levels. FIG. 10 shows two configurations of the loaded antenna which include three conducting surfaces, one of them bigger than the others. Drawing 45 shows a triangular conducting surface (45a) which is connected to two smaller circular conducting surfaces (45b) and (45c) through one conducting strip (45d) and (45e). Drawing 46 is a similar configuration to drawing 45 but the bigger conducting surface is a multilevel structure. FIG. 11 shows other particular cases of the loaded antenna. They consist of a monopole antenna comprising a conducting or superconducting ground plane (48) with an opening to allocate a coaxial cable (47) with its outer conductor connected to said ground plane and the inner conductor connected to the loaded antenna. The loaded radiator can be optionally placed over a supporting dielectric (49). FIG. 12 shows a top-loaded polygonal radiating element (50) mounted with the same configuration as the antenna in FIG. 12. The radiating element radiator can be optionally placed over a supporting dielectric (49). The lower drawing shows a configuration wherein the radiating element is printed on one of the sides of a dielectric substrate (49) and also the load has a conducting surface on the other side of the substrate (51). FIG. 13 shows a particular configuration of the loaded antenna. It consists of a dipole wherein each of the two arms includes two straight strip loads. The lines at the vertex of the small triangles (50) indicate the input terminal points. The two drawings display different configurations of the same basic dipole; in the lower drawing the radiating element is supported by a dielectric substrate (49). FIG. 14 shows, in the upper drawing, an example of the same dipole antenna side-loaded with two strips but fed as an aperture antenna. The lower drawing is the same loaded structure wherein the conductor defines the perimeter of the loaded geometry. FIG. 15 shows a patch antenna wherein the radiating element is a multilevel structure top-loaded with two strip arms, upper drawing. Also, the figure shows an aperture antenna wherein the aperture (59) is practiced on a conducting or superconducting structure (63), said aperture being shaped as a loaded multilevel structure. FIG. 16 shows a frequency selective surface wherein the elements that form the surface are shaped as a multilevel loaded structure. DETAILED DESCRIPTION OF SOME PREFERRED EMBODIMENTS A preferred embodiment of the loaded antenna is a monopole configuration as shown in FIG. 11. The antenna includes a conducting or superconducting counterpoise or ground plane (48). A handheld telephone case, or even a part of the metallic structure of a car or train can act as such a ground conterpoise. The ground and the monopole arm (here the arm is represented with the loaded structure (26), but any of the mentioned loaded antenna structure could be taken instead) are excited as usual in prior art monopole by means of, for instance, a transmission line (47). Said transmission line is formed by two conductors, one of the conductors is connected to the ground counterpoise while the other is connected to a point of the conducting or superconducting loaded structure. In FIG. 11, a coaxial cable (47) has been taken as a particular case of transmission line, but it is clear to any skilled in the art that other transmission lines (such as for instance a microstrip arm) could be used to excite the monopole. Optionally, and following the scheme just described, the loaded monopole can be printed over a dielectric substrate (49). Another preferred embodiment of the loaded antenna is a monopole configuration as shown in FIG. 12. The assembly of the antenna (feeding scheme, ground plane, etc) is the same as the considered in the embodiment described in FIG. 11. In the present figure, there is another example of the loaded antenna. More precisely, it consists of a trapezoid element top-loaded with one of the mentioned curves. In this case, one of the main differences is that, being the antenna edged on dielectric substrate, it also includes a conducting surface on the other side of the dielectric (51) with the shape of the load. This preferred configuration allows to miniaturize the antenna and also to adjust the multiband parameters of the antenna, such as the spacing the between bands. FIG. 13 describes a preferred embodiment of the invention. A two-arm antenna dipole is constructed comprising two conducting or superconducting parts, each part being a side-loaded multilevel structure. For the sake of clarity but without loss of generality, a particular case of the loaded antenna (26) has been chosen here; obviously, other structures, as for instance, those described in FIGS. 2,3,4,7 and 8, could be used instead. Both, the conducting surfaces and the loading structures are lying on the same surface. The two closest apexes of the two arms form the input terminals (50) of the dipole. The terminals (50) have been drawn as conducting or superconducting wires, but as it is clear to those skilled in the art, such terminals could be shaped following any other pattern as long as they are kept small in terms of the operating wavelength. The skilled in the art will notice that, the arms of the dipoles can be rotated and folded in different ways to finely modify the input impedance or the radiation properties of the antenna such as, for instance, polarization. Another preferred embodiment of a loaded dipole is also shown in FIG. 13 where the conducting or superconducting loaded arms are printed over a dielectric substrate (49); this method is particularly convenient in terms of cost and mechanical robustness when the shape of the applied load packs a long length in a small area and when the conducting surface contains a high number of polygons, as happens with multilevel structures. Any of the well-known printed circuit fabrication techniques can be applied to pattern the loaded structure over the dielectric substrate. Said dielectric substrate can be, for instance, a glass-fibre board, a teflon based substrate (such as Cuclad®) or other standard radiofrequency and microwave substrates (as for instance Rogers 4003® or Kapton®). The dielectric substrate can be a portion of a window glass if the antenna is to be mounted in a motor vehicle such as a car, a train or an airplane, to transmit or receive radio, TV, cellular telephone (GSM900, GSM1800, UMTS) or other communication services electromagnetic waves. Of course, a balun network can be connected or integrated at the input terminals of the dipole to balance the current distribution among the two dipole arms. The embodiment (26) in FIG. 14 consist on an aperture configuration of a loaded antenna using a multilevel geometry as the conducting surface. The feeding techniques can be one of the techniques usually used in conventional aperture antennas. In the described figure, the inner conductor of the coaxial cable (53) is directly connected to the lower triangular element and the outer conductor to the rest of the conductive surface. Other feeding configurations are possible, such as for instance a capacitive coupling. Another preferred embodiment of the loaded antenna is a slot loaded monopole antenna as shown in the lower drawing in FIG. 14. In this figure the loaded structure forms a slot or gap (54) impressed over a conducting or superconducting sheet (52). Such sheet can be, for instance, a sheet over a dielectric substrate in a printed circuit board configuration, a transparent conductive film such as those deposited over a glass window to protect the interior of a car from heating infrared radiation, or can even be a part of the metallic structure of a handheld telephone, a car, train, boat or airplane. The feeding scheme can be any of the well known in conventional slot antennas and it does not become an essential part of the present invention. In all said two illustrations in FIG. 14, a coaxial cable has been used to feed the antenna, with one of the conductors connected to one side of the conducting sheet and the other connected at the other side of the sheet across the slot. A microstrip transmission line could be used, for instance, instead of a coaxial cable. Another preferred embodiment is described in FIG. 15. It consists of a patch antenna, with the conducting or superconducting patch (58) featuring the loaded structure (the particular case of the loaded structure (59) has been used here but it is clear that any of the other mentioned structures could be used instead). The patch antenna comprises a conducting or superconducting ground plane (61) or ground counterpoise, and the conducting or superconducting patch which is parallel to said ground plane or ground counterpoise. The spacing between the patch and the ground is typically below (but not restricted to) a quarter wavelength. Optionally, a low-loss dielectric substrate (60) (such as glass-fibre, a teflon substrate such as Cuclad® or other commercial materials such as Rogers4003®) can be placed between said patch and ground counterpoise. The antenna feeding scheme can be taken to be any of the well-known schemes used in prior art patch antennas, for instance: a coaxial cable with the outer conductor connected to the ground plane and the inner conductor connected to the patch at the desired input resistance point (of course the typical modifications including a capacitive gap on the patch around the coaxial connecting point or a capacitive plate connected to the inner conductor of the coaxial placed at a distance parallel to the patch, and so on, can be used as well); a microstrip transmission line sharing the same ground plane as the antenna with the strip capacitively coupled to the patch and located at a distance below the patch, or in another embodiment with the strip placed below the ground plane and coupled to the patch through a slot, and even a microstrip line with the strip co-planar to the patch. All these mechanisms are well known from prior art and do not constitute an essential part of the present invention. The essential part of the invention is the loading shape of the antenna which contributes to enhance the behavior of the radiator to operate simultaneously at several bands with a small size performance. The same FIG. 15 describes another preferred embodiment of the loaded antenna. It consist of an aperture antenna, said aperture being characterized by its loading added to a multilevel structure, said aperture being impressed over a conducting ground plane or ground counterpoise, said ground plane consisting, for example, of a wall of a waveguide or cavity resonator or a part of the structure of a motor vehicle (such as a car, a lorry, an airplane or a tank). The aperture can be fed by any of the conventional techniques such as a coaxial cable (61), or a planar microstrip or strip-line transmission line, to name a few. Another preferred embodiment is described in FIG. 16. It consists of a frequency selective surface (63). Frequency selective surfaces are essentially electromagnetic filters, which at some frequencies they completely reflect energy while at other frequencies they are completely transparent. In this preferred embodiment the selective elements (64), which form the surface (63), use the loaded structure (26), but any other of the mentioned loaded antenna structures can be used instead. At least one of the selective elements (64) has the same shape of the mentioned loaded radiating elements. Besides this embodiment, another embodiment is preferred; this is, a loaded antenna where the conducting surface or the loading structure, or both, are shaped by means of one or a combination of the following mathematical algorithms: Iterated Function Systems, Multi Reduction Copy Machine, Networked Multi Reduction Copy Machine. | <SOH> BACKGROUND OF THE INVENTION <EOH>The growth of the telecommunication sector, and in particular, the expansion of personal mobile communication systems are driving the engineering efforts to develop multiservice (multifrequency) and compact systems which require multifrequency and small antennas. Therefore, the use of a multisystem small antenna with a multiband and/or wideband performance, which provides coverage of the maximum number of services, is nowadays of notable interest since it permits telecom operators to reduce their costs and to minimize the environmental impact. Most of the multiband reported antenna solutions use one or more radiators or branches for each band or service. An example is found in U.S. patent Ser. No. 09/129,176 entitled “Multiple band, multiple branch antenna for mobile phone”. One of the alternatives which can be of special interest when looking for antennas with a multiband and/or small size performance are multilevel antennas, Patent publication WO01/22528 entitled “Multilevel Antennas”, and miniature space-filling antennas, Patent publication WO01/54225 entitled “Space-filling miniature antennas”. In particular in the publication WO 01/22528 a multilevel antennae was characterised by a geometry comprising polygons or polyhedrons of the same class (same number of sides of faces), which are electromagnetically coupled and grouped to form a larger structure. In a multilevel geometry most of these elements are clearly visible as their arwea of contact, intersection or interconnection (if these exists) with other elements is always less than 50% of their perimeter or area in at least 75% of the polygons or polyhedrons. In the publication WO 01/54225 a space-filling miniature antenna was defined as an antenna havinf at least one part shaped as a space-filling-curve (SFC), being defined said SFC as a curve composed by at least ten connected straight segments, wherein said segments are smaller than a tenth of the operating free-space wave length and they are spacially arranged in such a way that none of said adjacent and connected segments from another longer straight segment. The international publication WO 97/06578 entitled fractal antennas, resonators and loading elements, describe fractal-shaped elements which may be used to form an antenna. A variety of techniques used to reduce the size of the antennas can be found in the prior art. In 1886, there was the first example of a loaded antenna; that was, the loaded dipole which Hertz built to validate Maxwell equations. A. G. Kandoian (A. G. Kandoian, Three new antenna types and their applications, Proc. IRE, vol. 34, pp. 70W-75W, February 1946) introduced the concept of loaded antennas and demonstrated how the length of a quarter wavelength monopole can be reduced by adding a conductive disk at the top of the radiator. Subsequently, Goubau presented an antenna structure top-loaded with several capacitive disks interconnected by inductive elements which provided a smaller size with a broader bandwith, as is illustrated in U.S. Pat. No. 3,967,276 entitled “Antenna structures having reactance at free end”. More recently, U.S. Pat. No. 5,847,682 entitled “Top loaded triangular printed antenna” discloses a triangular-shaped printed antenna with its top connected to a rectangular strip. The antenna features a low-profile and broadband performance. However, none of these antenna configurations provide a multiband behaviour. In Patent No. WO0122528 entitled “Multilevel Antennas”, another patent of the present inventors, there is a particular case of a top-loaded antenna with an inductive loop, which was used to miniaturize an antenna for a dual frequency operation. Also, W. Dou and W. Y. M. Chia (W. Dou and W. Y. M. Chia, “Small broadband stacked planar monopole”, Microwave and Optical Technology Letters, vol. 27, pp. 288-289, November 2000) presented another particular antecedent of a top-loaded antenna with a broadband behavior. The antenna was a rectangular monopole top-loaded with one rectangular arm connected at each of the tips of the rectangular shape. The width of each of the rectangular arms is on the order of the width of the fed element, which is not the case of the present invention. | <SOH> SUMMARY OF THE INVENTION <EOH>The key point of the present invention is the shape of the radiating element of the antenna, which consists on two main parts: a conducting surface and a loading structure. Said conducting surface has a polygonal, space-filling or multilevel shape and the loading structure consists on a conducting strip or set of strips connected to said conducting surface. According to the present invention, at least one loading strip must be directly connected at least at one point on the perimeter of said conducting surface. Also, circular or elliptical shapes are included in the set of possible geometries of said conducting surfaces since they can be considered polygonal structures with a large number of sides. Due to the addition of the loading structure, the antenna can feature a small and multiband, and sometimes a multiband and wideband, performance. Moreover, the multiband properties of the loaded antenna (number of bands, spacing between bands, matching levels, etc) can be adjusted by modifying the geometry of the load and/or the conducting surface. This novel loaded antenna allows to obtain a multifrequency performance, obtaining similar radioelectric parameters at several bands. The loading structure can consist for instance on a single conducting strip. In this particular case, said loading strip must have one of its two ends connected to a point on the perimeter of the conducting surface (i.e., the vertices or edges). The other tip of said strip is left free in some embodiments while, in other embodiments it is also connected at a point on the perimeter of said conducting surface. The loading structure can include not only a single strip but also a plurality of loading strips located at different locations along its perimeter. The geometries of the loads that can be connected to the conducting surface according to the present invention are: a) A curve composed by a minimum of two segments and a maximum of nine segments which are connected in such a way that each segment forms an angle with their neighbours, i.e., no pair of adjacent segments define a larger straight segment. b) A straight segment or strip c) A straight strip with a polygonal shape d) A space-filling curve, Patent No. PCT/ES00/00411 entitled “Space-filling miniature antennas”. In some embodiments, the loading structure described above is connected to the conducting surface while in other embodiments, the tips of a plurality of the loading strips are connected to other strips. In those embodiments where a new loading strip is added to the previous one, said additional load can either have one tip free of connection, or said tip connected to the previous loading strip, or both tips connected to previous strip or one tip connected to previous strip and the other tip connected to the conducting surface. There are three types of geometries that can be used for the conducting surface according to the present invention: a) A polygon (i.e., a triangle, square, trapezoid, pentagon, hexagon, etc. or even a circle or ellipse as a particular case of polygon with a very large number of edges). b) A multilevel structure, Patent No. WO0122528 entitled “Multilevel Antennas”. c) A solid surface with an space-filling perimeter. In some embodiments, a central portion of said conducting surface is even removed to further reduce the size of the antenna. Also, it is clear to those skilled in the art that the multilevel or space-filling designs in configurations b) and c) can be used to approximate, for instance, ideal fractal shapes. FIG. 1 and FIG. 2 show some examples of the radiating element for a loaded antenna according to the present invention. In drawings 1 to 3 the conducting surface is a trapezoid while in drawings 4 to 7 said surface is a triangle. It can be seen that in these cases, the conducting surface is loaded using different strips with different lengths, orientations and locations around the perimeter of the trapezoid, FIG. 1 . Besides, in these examples the load can have either one or both of its ends connected to the conducting surface, FIG. 2 . The main advantage of this novel loaded antenna is two-folded: The antenna features a multiband or wideband performance, or a combination of both. Given the physical size of radiating element, said antenna can be operated at a lower frequency than most of the prior art antennas. | 20040413 | 20071225 | 20060413 | 58900.0 | H01Q138 | 2 | WIMER, MICHAEL C | LOADED ANTENNA | UNDISCOUNTED | 1 | CONT-ACCEPTED | H01Q | 2,004 |
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10,823,045 | ACCEPTED | Optical system for projection display and a projection method thereof | An optical system for a projection display includes a light source, a light path switching device, and a total internal reflection (TIR) prism set disposed between the light path switching device and the projection lens. The light path switching device has a first mode of operation for directing the light towards a projection lens and a second mode of operation for directing the light away from the projection lens. The TIR prism set includes a first prism, a second prism and a third prism; a first gap is formed between the first prism and the second prism, and a second gap is formed between the first prism and the third prism. The light emitted from the light source enters the light path switching device by means of total internal reflection Then, under the first mode, the light reflected by the light path switching device passes through the first and the second gaps and enters the projection lens, whereas under the second mode, the light reflected by the light path switching device is totally reflected at the boundary between the first gap and the second prism and away from the projection lens. | 1. An optical system for a projection display, comprising: a light source for producing light; a light path switching device having a plurality of modes of operation for receiving and reflecting the light, the plurality of modes comprising at least a first mode for directing the light towards a projection lens of the projection display and a second mode for directing the light away from the projection lens; and a total internal reflection (TIR) prism set disposed between the light path switching device and the projection lens and comprising a first prism, a second prism and a third prism, a first gap being formed between the first prism and the second prism and a second gap being formed between the first prism and the third prism; wherein the light enters the light path switching device by means of total internal reflection; and, under the first mode, the light reflected by the light path switching device passes through the first and the second gaps and enters the projection lens, whereas under the second mode, the light reflected by the light path switching device is totally reflected at the boundary between the first gap and the second prism and away from the projection lens. 2. The optical system according to claim 1, wherein the light that is totally reflected at the boundary between the first gap and the second prism under the second mode is further reflected on the surface of the second prism closest to the light path switching device under the second mode. 3. The optical system according to claim 2, wherein the light leaves the optical system via a side surface of the second prism under the second mode, and a light-absorbing substance is applied on the side surface. 4. The optical system according to claim 3, wherein the light-absorbing substance is a light-absorbing layer coated on the side surface. 5. The optical system according to claim 1, wherein the light path switching device is a micromirror array that consists of a plurality of micromirrors each receiving and reflecting the light. 6. The optical system according to claim 1, further comprising a light guide disposed between the light source and the TIR prism set. 7. The optical system according to claim 6, further comprising a relay lens disposed between the light guide and the TIR prism set. 8. The optical system according to claim 1, wherein the light enters the optical system via the first prism; and the light leaves the optical system via the third prism under the first mode whereas it leaves the optical system via the second prism under the second mode. 9. A projection method for an optical system for a projection display comprising the steps of: guiding the light emitted from a light source onto a light path switching device having a first mode and a second mode of operation; disposing a TIR prism set between the light path switching device and a projection lens of the projection display, the TIR prism set comprising a plurality of prisms and a gap between each two adjacent prisms, TIR prism set which are arranged such that the light emitted from the light source is totally reflected to the light path switching device at the boundary between the gap and the prism that the light first meets when entering the optical system; and switching the light path switching device to direct the light reflected by the light path switching device onto a projection lens under the first mode and to direct it away from the projection lens under the second mode, a total internal reflection occurring at the boundary between the gap and the prism that the light reflected by the light path switching device first meets when entering the TIR prism set under the second mode. 10. The projection method according to claim 9, wherein the light reflected by the light path switching device is further totally reflected on the surface of the prism closest to the light path switching device under the second mode. 11. The projection method according to claim 9, wherein under the second mode the light leaves the optical system via a side surface of the prism that the light reflected by the light path switching device first meets, and a light-absorbing substance is applied on the side surface. 12. The projection method according to claim 9 wherein the light path switching device is a micromirror array that consists of a plurality of micromirrors each receiving and reflecting the light. | BACKGROUND OF THE INVENTION a. Field of the Invention The invention relates to an optical system for a projection display and, more particularly, to an optical system for a projection display capable of providing high image contrast and a wide viewing angle. b. Description of the Related Art A projection display typically consists of an illumination system and a projection system. The illumination system incorporates a light path switching device that consists of a plurality of relatively small elements each being used to switch light path individually. After being modulated by the switching elements, light beams emitted from a light source are projected on a projection surface through the projection system. A digital micromirror device (DMD) manufactured by Texas Instruments (TI), as an example of a light path switching device, is composed of thousands of micromirrors. The DMD panel's micromirrors are mounted on tiny hinges that enable them to tilt either toward the light source (ON mode) or away from it (OFF mode), thus creating a light or dark pixel on the projection surface. FIG. 1 is a schematic view showing a conventional optical system 100 for a projection display. Referring to FIG. 1, the tiltable micromirrors on a digital micromirror device 102 may either direct the incoming light l onto a projection lens 104 along path 108 under the “On mode” or direct it away from the projection lens 104 along path 110 under the “Off mode”, thereby creating a light or dark pixel on the projection surface. A total internal reflection (TIR) prism set 106, composed of two prisms 106a and 106b adhered to each other with an air gap 112 interposed therebetween, is disposed in a light path between the digital micromirror device 102 and the projection lens 104. The TIR prism set 106, inside which total internal reflection occurs at the boundary between the prism 106b and the air gap 112, guides the incoming light l to the digital micromirror device 102 along the light path shown in FIG. 1. However, through such design, since the tilting range of the micromirror is limited, the light path of the incoming light l between the digital micromirror device 102 and the projection lens 104 under the On mode is almost the same as that under the Off mode; hence, an edge portion of the spread-out incoming light l enters the projection lens 104 under the Off mode to result in a deterioration in the image contrast. Though this problem may be solved by increasing the distance between the projection lens 104 and the TIR prism set 106 to prevent stray light from entering the projection lens under the Off mode, the back focal length, however, is increased accordingly, and thus it is difficult to design a projection lens with a wide viewing angle. FIGS. 2A and 2B are schematic views showing another optical system 200 for a projection display. The TIR prism set 206 of the optical system 200 includes three prisms, and air gaps 208 and 210 are formed between each two adjacent prisms. Under the On mode as shown in FIG. 2A, the incoming light l enters the digital micromirror device 202 due to the total internal reflection occurring at the boundary between the air gap 208 and the prism. Then, the light l reflected by the micromirror on the digital micromirror device 202 passes through the TIR prism set 206 and enters a projection lens 204 along a non-reflected optical axis. On the other hand, as shown in FIG. 2B, under the Off mode the light reflected by the micromirror on the digital micromirror device 202 is reflected outside the optical system 200 due to the total internal reflection occurring at the boundary between the air gap 210 and the prism. Such TIR prism set 206 may render the light paths under the On mode and the Off mode more distinguishable to prevent stray light from entering the projection lens. However, the width W along the non-reflected optical axis of the assembled TIR prism set 206 becomes larger and the back focal length is increased, thus it is also difficult to design a projection lens with a wide viewing angle. BRIEF SUMMARY OF THE INVENTION An object of the invention is to provide an optical system for a projection display capable of eliminating the stray light to enhance the image contrast and shortening the back focal length to provide a projection display with a wide viewing angle. According to the invention, the optical system includes a light source, a light path switching device, and a total internal reflection (TIR) prism set disposed between the light path switching device and the projection lens. The light path switching device has a first mode of operation for directing the light towards a projection lens and a second mode of operation for directing the light away from the projection lens. The TIR prism set includes a first prism, a second prism and a third prism; a first gap is formed between the first prism and the second prism, and a second gap is formed between the first prism and the third prism. The light emitted from the light source enters the light path switching device by means of total internal reflection. Then, under the first mode, the light reflected by the light path switching device passes through the first and the second gaps and enters the projection lens, whereas under the second mode, the light reflected by the light path switching device is totally reflected at the boundary between the first gap and the second prism and away from the projection lens. Through the design of the invention, the light reflected by the light path switching device under the “Off” mode is totally reflected at the boundary between the air gap and the prism that the light reflected by the light path switching device first meets when entering the TIR prism set. Thus, since the incoming light l that is to be removed under the “Off” mode is quickly and completely directed away from the projection lens, the overall thickness along the non-reflected optical axis of the assembled TIR prism set can be greatly reduced, and the back focal length is decreased as a result. Consequently, a wide viewing angle for the projection lens can be achieved easily. Also, according to the invention, the TIR prism set can be shaped to provide the total internal reflection for restricting the light path through which the light reflected by the micromirror array travels under the Off mode. Hence, it can be further ensured that the stray light no longer enters the projection lens under the Off mode. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a conventional optical system for a projection display FIGS. 2A and 2B are schematic views showing another optical system for a projection display. FIG. 3 is a schematic view showing an optical system for a projection display according to an embodiment of the invention. FIGS. 4A and 4B exhibit the light paths through which the incoming light l travels after entering the TIR prism set according to an embodiment of the invention, where FIG. 4A shows the light path under the On mode while FIG. 4B shows that under the Off mode. FIG. 5 shows an actual dimension of an assembled TIR prism set of the invention compared to that of the prior art. FIG. 6 is a schematic view showing a modification of the TIR prism set according to another embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 3, an optical system 10 for a projection display includes a light source 12, a light guide 14, a relay lens 16, a total internal reflection (TIR) prism set 18, a light path switching device 20, and a projection lens 22. A light collector such as an ellipsoid mirror 30 may be arranged to partially surround the light source 12 to focus the light beams, emitted from the light source 12, onto the light guide 14. The light guide 14, which is hollow with interior reflecting walls where total internal reflections successively occur, receives the light beams from the light source 12 and outputs them as evenly distributed light beams. The evenly distributed light beams are then projected on the TIR prism set 18 after passing through the relay lens 16. A micromirror array 20a consists of a plurality of tiltable micromirrors is disposed on the light path switching device 20. The tiltable micromirrors may either direct the incoming light onto a projection lens 22 under the “On mode” or direct it away from the projection lens 22 under the “Off mode”, thereby creating a light or dark pixel on a projection surface. It should be noted that the modes of operation of the tiltable micromirrors include, but are not limited to, the aforesaid “On mode” and “Off mode”, and can be adapted to the actual demand of the light modulation. FIGS. 4A and 4B exhibit the light paths through which the incoming light l travels after entering the TIR prism set 18 according to an embodiment of the invention, where FIG. 4A shows the light path under the On mode while FIG. 4B shows that under the Off mode. In this embodiment, the TIR prism set 18 is composed of a prism 18a adjacent to the light guide 14, a prism 18b adjacent to the light path switching device 20, and a prism 18c adjacent to the projection lens 22. An air gap 24 is formed between the prism 18a and the prism 18c, and another air gap 26 is formed between the prisms 18a and 18b. The incoming light l first strikes the boundary between the prism 18a and the air gap 24 at a predetermined incident angle, which is greater than the critical angle calculated from the Snell's law, so that the incoming light l is totally reflected to the light path switching device 20. Referring to FIG. 4A, when micromirror array 20a is tilted under the On mode, the light reflected by the micromirror array 20a sequentially passes through the air gap 26 and air gap 24 along a non-reflected optical axis and then enters the projection lens 22. On the other hand, as shown in FIG. 4B, under the Off mode the light reflected by the micromirror array 20a strikes the boundary between the prism 18b and the air gap 26 at an incident angle, which is also designed to be greater than the critical angle calculated from the Snell's law. Hence, through the design of the invention, the incoming light l that is to be removed under the Off mode is quickly and completely directed away from the projection lens 22, for it is totally reflected at the boundary between the prism 18b and the air gap 26. In other words, the light reflected by the micromirror array 20a under the Off mode is further totally reflected at the boundary between the air gap 26 and the prism 18b, and the prism 18b is the prism that the light reflected by the micromirror array 20a first meets when entering the TIR prism set 18. Further, the TIR prism set 18 of the invention is designed such that the light reflected at the boundary between the prism 18b and the air gap 26 is totally reflected again on the surface S1 of the prism 18b closest to the micromirror array 20a. In addition, the prism 18b can be shaped such that the light reflected by the surface S1 may further strike the prism surface opposed to the surface S1 at an incident angle greater than the critical angle. Therefore, the traveling path of the incoming light 1 under the Off mode is restricted within the prism 18b as shown in FIG. 4B, and, finally, the light leaves the optical system via the side surface S2 of the prism 18b to further ensure that the stray light no longer enters the projection lens 22 under the Off mode. Furthermore, since the light under the Off mode leaves the optical system via the side surface S2 of the prism 18b, a light-absorbing substance may be applied to the side surface S2 so as to absorb the light. For example, a light absorbing layer 28 may be coated on the side surface S2 of the prism 18b. Through the TIR prism set design of the invention, the light reflected by the micromirror array 20a under the “Off” mode is totally reflected at the boundary between the air gap and the prism that the light reflected by the micromirror array 20a first meets when entering the TIR prism set. Thus, since the incoming light l that is to be removed under the “Off” mode is quickly and completely directed away from the projection lens 22, the overall thickness along the non-reflected optical axis of the assembled TIR prism set can be greatly reduced, and the back focal length is decreased as a result. This makes it easy to design a projection lens having a wide viewing angle. Also, according to the invention, the TIR prism set can be shaped to provide the total internal reflection for restricting the light path through which the light reflected by the micromirror array travels under the Off mode. As a result, it can be further ensured that the stray light no longer enters the projection lens under the Off mode. FIG. 5 shows the actual dimension along the non-reflected optical axis of an assembled TIR prism set of the invention (on the right) compared to the prior art (on the left). It should be noted that the dimension shown in the figure are determined under the same conditions for providing total internal reflection; for instance, the material of the TIR prism set and the adopted micromirror array are the same. As for the width W along the non-reflected optical axis of the assembled TIR prism set, the conventional three-piece TIR prism set 206 has a thickness W equal to 77.2 mm while the TIR prism set 18 of the invention has a thickness W′ equal to only 23.96 mm. FIG. 6 is a schematic view showing a modification of the TIR prism set 18 according to another embodiment of the invention. According to the invention, the TIR prism set design is required only to maintain an air gap between adjacent prisms to provide the total internal reflection, and the shape or arrangement of the prisms can be adapted to conform to the actual light path. For instance, if the light path of the optical system needs to be shortened, the conventional method is to dispose an additional reflection mirror to change the light path of the incoming light 1. However, in this embodiment, the shape of the prism 18a may be modified so that it becomes a quadrangular prism where an additional reflection surface R is provided, as shown in FIG. 6. Thereby, the incoming light l is first reflected by the reflection surface R and then incident at the boundary between the prism 18a and the air gap 24, where the total internal reflection occurs. Hence, the light path in the optical system can be changed without the need of any additional element such as a reflection mirror, and thus it is possible to reduce the manufacturing cost and facilitate the assembly. While the invention has been described by way of examples and in terms of preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications. | <SOH> BACKGROUND OF THE INVENTION <EOH>a. Field of the Invention The invention relates to an optical system for a projection display and, more particularly, to an optical system for a projection display capable of providing high image contrast and a wide viewing angle. b. Description of the Related Art A projection display typically consists of an illumination system and a projection system. The illumination system incorporates a light path switching device that consists of a plurality of relatively small elements each being used to switch light path individually. After being modulated by the switching elements, light beams emitted from a light source are projected on a projection surface through the projection system. A digital micromirror device (DMD) manufactured by Texas Instruments (TI), as an example of a light path switching device, is composed of thousands of micromirrors. The DMD panel's micromirrors are mounted on tiny hinges that enable them to tilt either toward the light source (ON mode) or away from it (OFF mode), thus creating a light or dark pixel on the projection surface. FIG. 1 is a schematic view showing a conventional optical system 100 for a projection display. Referring to FIG. 1 , the tiltable micromirrors on a digital micromirror device 102 may either direct the incoming light l onto a projection lens 104 along path 108 under the “On mode” or direct it away from the projection lens 104 along path 110 under the “Off mode”, thereby creating a light or dark pixel on the projection surface. A total internal reflection (TIR) prism set 106 , composed of two prisms 106 a and 106 b adhered to each other with an air gap 112 interposed therebetween, is disposed in a light path between the digital micromirror device 102 and the projection lens 104 . The TIR prism set 106 , inside which total internal reflection occurs at the boundary between the prism 106 b and the air gap 112 , guides the incoming light l to the digital micromirror device 102 along the light path shown in FIG. 1 . However, through such design, since the tilting range of the micromirror is limited, the light path of the incoming light l between the digital micromirror device 102 and the projection lens 104 under the On mode is almost the same as that under the Off mode; hence, an edge portion of the spread-out incoming light l enters the projection lens 104 under the Off mode to result in a deterioration in the image contrast. Though this problem may be solved by increasing the distance between the projection lens 104 and the TIR prism set 106 to prevent stray light from entering the projection lens under the Off mode, the back focal length, however, is increased accordingly, and thus it is difficult to design a projection lens with a wide viewing angle. FIGS. 2A and 2B are schematic views showing another optical system 200 for a projection display. The TIR prism set 206 of the optical system 200 includes three prisms, and air gaps 208 and 210 are formed between each two adjacent prisms. Under the On mode as shown in FIG. 2A , the incoming light l enters the digital micromirror device 202 due to the total internal reflection occurring at the boundary between the air gap 208 and the prism. Then, the light l reflected by the micromirror on the digital micromirror device 202 passes through the TIR prism set 206 and enters a projection lens 204 along a non-reflected optical axis. On the other hand, as shown in FIG. 2B , under the Off mode the light reflected by the micromirror on the digital micromirror device 202 is reflected outside the optical system 200 due to the total internal reflection occurring at the boundary between the air gap 210 and the prism. Such TIR prism set 206 may render the light paths under the On mode and the Off mode more distinguishable to prevent stray light from entering the projection lens. However, the width W along the non-reflected optical axis of the assembled TIR prism set 206 becomes larger and the back focal length is increased, thus it is also difficult to design a projection lens with a wide viewing angle. | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>An object of the invention is to provide an optical system for a projection display capable of eliminating the stray light to enhance the image contrast and shortening the back focal length to provide a projection display with a wide viewing angle. According to the invention, the optical system includes a light source, a light path switching device, and a total internal reflection (TIR) prism set disposed between the light path switching device and the projection lens. The light path switching device has a first mode of operation for directing the light towards a projection lens and a second mode of operation for directing the light away from the projection lens. The TIR prism set includes a first prism, a second prism and a third prism; a first gap is formed between the first prism and the second prism, and a second gap is formed between the first prism and the third prism. The light emitted from the light source enters the light path switching device by means of total internal reflection. Then, under the first mode, the light reflected by the light path switching device passes through the first and the second gaps and enters the projection lens, whereas under the second mode, the light reflected by the light path switching device is totally reflected at the boundary between the first gap and the second prism and away from the projection lens. Through the design of the invention, the light reflected by the light path switching device under the “Off” mode is totally reflected at the boundary between the air gap and the prism that the light reflected by the light path switching device first meets when entering the TIR prism set. Thus, since the incoming light l that is to be removed under the “Off” mode is quickly and completely directed away from the projection lens, the overall thickness along the non-reflected optical axis of the assembled TIR prism set can be greatly reduced, and the back focal length is decreased as a result. Consequently, a wide viewing angle for the projection lens can be achieved easily. Also, according to the invention, the TIR prism set can be shaped to provide the total internal reflection for restricting the light path through which the light reflected by the micromirror array travels under the Off mode. Hence, it can be further ensured that the stray light no longer enters the projection lens under the Off mode. | 20040413 | 20050524 | 20050127 | 74368.0 | 0 | KOVAL, MELISSA J | OPTICAL SYSTEM FOR PROJECTION DISPLAY AND A PROJECTION METHOD THEREOF | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,823,198 | ACCEPTED | Cargo rack | A cargo rack utilizing structural beams, structural beams used in a framework comprising a plurality of vertical posts with either key shaped apertures or slots and a plurality of horizontal shelving members, structural beams contain either circular apertures when corresponding vertical post contains key shaped apertures or fingers when corresponding vertical post contains slots enabling structural beams to connect to vertical posts, thus allowing horizontal shelving members to be associated with structural beams and vertical posts. | 1. A framework that can be used for storage comprising: recessed structural beams having a return flange at their base, a recessed flange at their top, and a rib there between, said recessed structural beams being positioned horizontally and parallel with the ground to define parallelograms there between, at least four parallel vertical posts, each extending at a right angle to said recessed structural beams and being positioned at each of the corners of the parallelogram formed by said recessed structural beams, at least three shelf members shaped substantially in the form of said parallelograms formed by said recessed structural beams, and said recessed structural beams being removeably associated to vertical posts to form four corners, thereby enabling said shelf members to be supported by said recessed structural beams and removeably secured by said recessed flanges of said recessed structural beams. 2. A framework as defined in claim 1 wherein said recessed structural beams include a variable number of fingers formed from the ends of said recessed structural beams proportionately located near the base and top in a combination that will enable the assembly of said recessed structural beams to said vertical posts. 3. A framework as defined in claim 2 wherein said vertical posts include two perpendicular planes which meet at a right angle, said posts are orientated to create a corner open to said recessed structural beams, and each plane of said vertical posts contain slots spaced from the top of said vertical posts to the base of said vertical posts enabling said vertical posts to fasten to said structural beam. 4. A process of assembling a framework as defined in claim 3 by way of: orientating the recessed flange on each of said recessed structural beams toward the center of the parallelogram created by four recessed structural beams, aligning said fingers on each of said recessed structural beams with the upper opening of said slots on said vertical posts, inserting the bottom portion of said fingers into the top portion of said slots of said vertical posts which enables the fingers to securely fasten said recessed structural beams to said vertical posts by dropping vertically until the edge of said finger comes into contact with the top of said slots thereby creating a tight fit, this insertion of said fingers with said slots is executed at both ends of said recessed structural beams with corresponding vertical posts, and said shelf member is removeably secured to recessed structural beams by resting on said recessed flanges of each of four said recessed structural beams, which combines with said taper allowing slight clearance at the top of said shelf member for various attachments. 5. A framework as defined in claim 1 wherein said recessed structural beams include a variable number of circular apertures on the ends of said recessed structural beams proportionately located near the base and top in a combination that will enable the assembly of said recessed structural beams to said vertical posts. 6. A framework as defined in claim 5 wherein said vertical posts include two perpendicular planes which meet at a right angle, said posts are orientated to create a corner open to said recessed structural beams, and each plane of said vertical posts contain key shaped apertures spaced from the top of said vertical posts to the base of said vertical posts enabling said vertical posts to fasten to said recessed structural beams. 7. A process of assembling a framework as defined in claim 6 by way of: orientating the recessed flange on each of said recessed structural beams toward the center of the parallelogram created by said four recessed structural beams, aligning said circular apertures on said recessed structural beams with said key shaped apertures on said vertical posts, inserting screws or bolts though the circular apertures on said recessed structural beams and lower portion of the key shaped apertures of said vertical posts, fastening nuts to said screws or bolts thereby securing said recessed structural beams to said vertical posts by creating a tight fit, and said shelf member being removeably secured to recessed structural beams by resting on said recessed flanges of each of four said recessed structural beams, which combines with said taper allowing slight clearance at the top of said shelf member for various attachments. 8. A framework that can be used for storage comprising: recessed structural beams having a return flange at their base and a recessed flange at their top, said recessed structural beams being positioned horizontally and parallel with the ground to define parallelograms there between, at least four parallel vertical posts, each extending at a right angle to said recessed structural beams and being positioned at each of the corners of the parallelogram formed by said recessed structural beams, at least three shelf members shaped substantially in the form of said parallelograms formed by said recessed structural beams, and said recessed structural beams being removeably associated to vertical posts to form four corners, thereby enabling said shelf members to be supported by said recessed structural beams and removeably secured by said recessed flanges of said recessed structural beams. 9. A framework as defined in claim 8 wherein said recessed structural beams include a variable number of fingers formed from the ends of said recessed structural beams proportionately located near the base and top in a combination that will enable the assembly of said recessed structural beams to said vertical posts. 10. A framework as defined in claim 9 wherein said vertical posts include two perpendicular planes which meet at a right angle, said posts are orientated to create a corner open to said recessed structural beams, and each plane of said vertical posts contain slots spaced from the top of said vertical posts to the base of said vertical posts enabling said vertical posts to fasten to said structural beam. 11. A process of assembling a framework as defined in claim 10 by way of: orientating the recessed flange on each of said recessed structural beams toward the center of the parallelogram created by four recessed structural beams, aligning said fingers on each of said recessed structural beams with the upper opening of said slots on said vertical posts, inserting the bottom portion of said fingers into the top portion of said slots of said vertical posts which enables the fingers to securely fasten said recessed structural beams to said vertical posts by dropping vertically until the edge of said finger comes into contact with the top of said slots thereby creating a tight fit, this insertion of said fingers with said slots is executed at both ends of said recessed structural beams with corresponding vertical posts, and said shelf member is removeably secured to recessed structural beams by resting on said recessed flanges of each of four said recessed structural beams, which combines with said taper allowing slight clearance at top of said shelf member for various attachments. 12. A framework as denied in claim 8 wherein said recessed structural beams include a variable number of circular apertures on the ends of said recessed structural beams proportionately located near the base and top in a combination that will enable the assembly of said recessed structural beams to said vertical posts. 13. A framework as defined in claim 12 wherein said vertical posts include two perpendicular planes which meet at a right angle, said posts are orientated to create a corner open to said recessed structural beams, and each plane of said vertical posts contain key shaped apertures spaced from the top of said vertical posts to the base of said vertical posts enabling said vertical posts to fasten to said recessed structural beams. 14. A process of assembling a framework as defined in claim 13 by way of: orientating the “L” shaped recessed flange on each of said recessed structural beams toward the center of the parallelogram created by said four recessed structural beams, aligning said circular apertures on said recessed structural beams with said key shaped apertures on said vertical posts, inserting screws or bolts through the circular apertures on said recessed structural beams and lower portion of the key shaped apertures of said vertical posts, fastening nuts to said screws or bolts thereby securing said recessed structural beams to said vertical posts by creating a tight fit, and said shelf member is removeably secured to recessed structural beams by resting on said recessed flanges of each of four said recessed structural beams, which combines with said taper allowing slight clearance at the top of said shelf member for various attachments. 15. A framework that can be used for storage comprising: standard structural beams having an angled return flange at their base, an angled standard flange at their top, and a rib there between, said standard structural beams being positioned horizontally and parallel with the ground to define parallelograms there between, at least four parallel vertical posts, each extending at a right angle to said standard structural beams and being positioned at each of the corners of the parallelogram formed by said standard structural beams, at least three shelf members shaped substantially in the form of said parallelograms formed by said standard structural beams, and said standard structural beams being removeably associated to vertical posts to form four corners, thereby enabling said shelf members to be supported by said standard structural beams and removeably secured by said standard angled flanges of said standard structural beams. 16. A framework as defined in claim 15 wherein said standard structural beams include a variable number of fingers formed from the ends of said standard structural beams proportionately located near the base and top in a combination that will enable the assembly of said standard structural beams to said vertical posts. 17. A framework as defined in claim 16 wherein said vertical posts include two perpendicular planes which meet at a right angle, said posts are orientated to create a corner open to said standard structural beams, and each plane of said vertical posts contain slots spaced from the top of said vertical posts to the base of said vertical posts enabling said vertical posts to fasten to said standard structural beam. 18. A process of assembling a framework as defined in claim 17 by way of: orientating the standard structural beams so that the flanges are directed toward the center of the parallelogram created by four standard structural beams, aligning said fingers on each of said standard structural beams with the upper opening on said slots on said vertical posts, inserting the bottom portion of said fingers into the top portion of said slots on said vertical posts which enables the fingers to securely fasten said standard structural beams to said vertical posts by dropping vertically until the edge of said finger comes into contact with the top of said slots thereby creating a tight fit, this insertion of said fingers with said slots is executed at both ends of said standard structural beams with corresponding vertical posts, and said shelf member is removeably secured to standard structural beams by resting on said standard angled flange of each of four said standard structural beams. 19. A framework as denied in claim 15 wherein said standard structural beams include a variable number of circular apertures on the ends of said standard structural beams proportionately located near the base and top in a combination that will enable the assembly of said standard structural beams to said vertical posts. 20. A framework as defined in claim 19 wherein said vertical posts include two perpendicular planes which meet at a right angle, said posts are orientated to create a corner open to said standard structural beams, and each plane of said vertical posts contain key shaped apertures spaced from the top of said vertical posts to the base of said vertical posts enabling said vertical posts to fasten to said standard structural beams. 21. A process of assembling a framework as defined in claim 20 by way of: orientating the standard structural beams so that the flanges are directed toward the center of the parallelogram created by said four standard structural beams, aligning said circular apertures on said standard structural beams with said key shaped apertures on said vertical posts, inserting screws or bolts though the circular apertures on said standard structural beams and lower portion of the key shaped apertures of said vertical posts, fastening nuts to said screws or bolts thereby securing said standard structural beams to said vertical posts by creating a tight fit, and said shelf member being removeably secured to standard structural beams by resting on said angled flange of each of four said standard structural beams. 22. A recessed structural beam for use with a storage unit comprising: a horizontal return flange on the base of said recessed structural beam extending the full length of said recessed structural beam, a rib strategically positioned between said recessed structural beam's base and top, which extends the full length of said recessed structural beam, a recessed flange at top of said recessed structural beam taking the form of “L” shape where the base of said “L” is parallel to the horizontal return flange located at the base of said recessed structural beam, the recessed flange is chamfered at both ends of said recessed structural beam enabling said recessed structural beams to create a corner fit, and a variable number of fingers formed from the ends of said recessed structural beams proportionately located near the base and top in a combination that can enable the assembly of said recessed structural beams to said vertical posts. 23. A recessed structural beam for use with a storage unit comprising: a horizontal return flange on the base of said recessed structural beam extending the full length of said recessed structural beam, a rib strategically positioned between said recessed structural beam's base and top, which extends the full length of said recessed structural beam, a recessed flange at top of said recessed structural beam taking the form of “L” shape where the base of said “L” is parallel to the horizontal return flange located at the base of said recessed structural beam, the recessed flange is chamfered at both ends of said recessed structural beam enabling said recessed structural beams to create a corner fit, and a variable number of circular apertures on the ends of said recessed structural beams proportionately located near the base and top in a combination that will enable the assembly of said recessed structural beams to said vertical posts. 24. A recessed structural beam for use with a storage unit comprising: a horizontal return flange on the base of said recessed structural beam extending the full length of said recessed structural beam, a recessed flange at top of said recessed structural beam taking the form of “L” shape where the base of said “L” is parallel to the horizontal return flange located at the base of said recessed structural beam, the recessed flange is chamfered at both ends of said recessed structural beam enabling said recessed structural beams to create a corner fit, and a variable number of fingers formed from the ends of said recessed structural beams proportionately located near the base and top in a combination that will enable the assembly of said recessed structural beams to said vertical posts. 25. A recessed structural beam for use with a storage unit comprising: a horizontal return flange on the base of said recessed structural beam extending the full length of said recessed structural beam, a recessed flange at top of said recessed structural beam taking the form of “L” shape where the base of said “L” is parallel to the horizontal return flange located at the base of said recessed structural beam, the recessed flange is chamfered at both ends of said recessed structural beam enabling said recessed structural beams to create a corner fit, and a variable number of circular apertures on the ends of said recessed structural beams proportionately located near the base and top in a combination that will enable the assembly of said recessed structural beams to said vertical posts. 26. A standard structural beam for use with a storage unit comprising: an angled return flange so that the beam forms an acute angle of approximately 85 degrees on the base of said standard structural beam extending the full length of said standard structural beam, a rib strategically positioned between said standard structural beam's base and top, which extends the full length of each of said standard structural beam, a standard angled flange at top of said standard structural beam so that the beam forms an acute angle of approximately 85 degrees at the top of said standard structural beam extending the full length of said structural beam, said angled flange is chamfered at both ends of said standard structural beam enabling said standard structural beams to create a corner fit, and a variable number of fingers formed from the ends of said standard structural beams proportionately located near the base and top in a combination that will enable the assembly of said standard structural beams to said vertical posts. 27. A standard structural beam for use with a storage unit comprising: an angled return flange wherein said beam forms an acute angle of approximately 85 degrees on the base of said standard structural beam extending the full length of said standard structural beam, a rib strategically positioned between said standard structural beam's base and top, which extends the full length of each of said standard structural beam, a standard angled flange at top of said standard structural beam wherein said that the beam forms an acute angle of approximately 85 degrees at the top of said standard structural beam extending the full length of said structural beam, and said angled flange being chamfered at both ends of said standard structural beam thereby enabling said standard structural beams to create a corner fit, and a variable number of circular apertures on the ends of said standard structural beams proportionately located near the base and top in a combination that will enable the assembly of said standard structural beams to said vertical posts. | This application is a continuation in part from patent application Ser. No. 10/715000 with a filing date of Nov. 17, 2003. Edsal Manufacturing Co., Inc. is the assignee of this application and application Ser. No. 10/715000. There are one or more inventors in common between the applications. BACKGROUND OF THE INVENTION This invention relates in general to a shelving unit and more particularly to the structural beams in the shelving unit. Several products are similar to this product in that they rely on beams affixed to posts to form a rigid shell that in turn supports shelf members. The same problems and disadvantages associated with prior art disclosed in the original CARGO-RACK patent application nonetheless exist for purposes of this Continuation-in-Part application. Generally, the disadvantages related to inadequate load bearing capacities, over-sized units, multiplicity of components required for assembly along with potential instability of shelving units. BRIEF SUMMARY OF THE INVENTION The shelving unit of the present invention preferably includes at least 4 vertical post members mutually spaced from one another. The structural beams are orientated perpendicular to vertical post members and removeably associated therewith taking the form of a parallelogram. The shelving unit is complete when shelf members are removeably associated to the structural beam and vertical post framework. Acknowledging the same problems and disadvantages associated with the prior art as disclosed in the original CARGO-RACK patent application Ser. No. 10/715000, this Continuation-in-Part CARGO-RACK patent application serves to provide additional assemblies discovered by the inventors to associate the structural beams to the vertical posts. Incorporating these additional methods provides additional means to easily assemble the shelving unit while still minimizing cost per unit, maximizing strength to material weight ratio, and ensuring that cargo will be adequately supported. These features will become more clearly understood upon consideration of the following detailed description and accompanying drawings. For purposes of clarity, we are herein incorporating by reference the following portions of the parent application filed on Nov. 17, 2003, pages 6-9, and any other parts of the Parent Application that provide support for certain claims of this case: “The recessed structural beams 2 include a rib 8, with a recessed flange 6, and a return flange 4 as seen in FIG. 5. The rib 8, recessed flange 6, and return flange 4 terminate in a vertical edge of the recessed structural beam 2. The recessed flange 6 is chamfered at the ends of its base 7 in order to enable assembly to appear as seen in FIG. 4 once it has moved along the dashed lines to engage the legs 20, 21 of the vertical post 10.” “The recessed structural beams 30 combine a recessed flange 31 and a return flange 32 as seen in FIG. 13. The recessed flange 31 and return flange 32 terminate in a vertical edge of the recessed structural beam 30. The recessed flange 31 is chamfered at its base 33 in order to enable assembly much in the same way as recessed flange 6 is chamfered at its base 7 on recessed structural beams 2 as shown in FIG. 4 once it has moved along the dashed lines to engage the legs 20, 21 of the vertical post 10.” “The standard structural beams 25 includes a rib 26 formed between an angled standard flange 27 and an angled return flange 28 as seen in FIG. 11. The rib 26, angled standard flange 27, and angled return flange 28 terminate in a vertical edge of the standard structural beam 25. The angled standard flange 27 is chamfered in order to enable standard structural beam assembly to appear as seen in FIG. 10 once it has moved along the dashed lines to engage the legs 20, 21 of vertical post 10.” “Once structural beams 2, 25, or 30 are associated to vertical post 10, it is then possible to removeably associate shelf member 12 to the unit thereby completing the shelving unit 1.” BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING FIG. 1 is an isometric view of the shelving unit; FIG. 2 is a broken view of the apertures on a vertical post; FIG. 3 is a broken view illustrating the connection between the shelving member and the structural beam via the recessed flange; FIG. 4 is an exploded view illustrating the recessed structural beam with ribbing to vertical post assembly via nubs and apertures; FIG. 5 is a cross sectional view of the profile of the recessed structural beam with ribbing; FIG. 6 is a corner view illustrating a shelf member being installed and positioned by the recessed flange; FIG. 7 is a broken top view of the corner of the shelving unit; FIG. 8 is a pictorial view of an example of one profile possible with an attachment; FIG. 9 is the side view of the example profile for the attachment shown in FIG. 8; FIG. 10 is an exploded view illustrating a standard structural beam with ribbing being assembled to vertical post via nubs and apertures; FIG. 11 is a cross sectional view taken along a plane passing through the line 11/11 and looking in the direction of the arrows of the line 11/11 of the standard structural beam; FIG. 12 is a corner view illustrating a shelf member being installed and positioned by the standard beam with ribbing and the angled flange; and FIG. 13 is a cross sectional profile of the recessed structural beam without ribbing. FIG. 14 is a broken/exploded view illustrating the connection of the vertical post and the structural beams incorporating the nut-bolt embodiment; FIG. 15 is an isometric view of the slot embodiment shelving unit; FIG. 16 is a broken view of the slots on a vertical post; and FIG. 17 is a broken/exploded view illustrating the connection of the vertical post and the structural beams incorporating the finger-slot embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, the assembled shelving unit 1 is shown including four vertical posts 10. Each vertical post 10 has a pair of legs 20, 21 perpendicular to one another as shown in FIG. 14. As shown in FIGS. 1 and 14, a plurality of structural beams 50 and horizontal shelving members 12 extend between the pairs of legs 20, 21 on vertical posts 10 and may be attached in a manner that is described below. The structural beams 50 contain circular apertures 51 which can be seen in FIG. 14. The purpose of circular apertures 51 are to provide means for the structural beams 50 to become associated with vertical posts 10. A pair of the circular apertures 51 are located at each end of structural beam 50. The vertical location of each pair of circular apertures 51 is relative to the vertical distance between the key shaped apertures 18 on legs 20 and 21 on vertical post 10. Furthermore, each pair of circular apertures 51 will be generally proportionate across the vertical centerline of structural beams 50. As seen in FIGS. 2 and 14, the vertical post 10 is provided with a plurality of key shaped apertures 18 comprising a circular hole 19 with a slot 19a that extends downward from the larger circular hole 19. To assemble the framework, the vertical posts 10 should be orientated in a way such that the legs 20, 21 of each post 10 are aligned with legs 20, 21 of the remaining 3 posts to form a rectangular shape within the legs 20, 21 of all four posts 10. The structural beams 50 can then be removeably associated with vertical posts 10 through the use of screws/bolts 52 and nuts 53 as seen in FIG. 14. In operation, the circular apertures 51 on structural beam 50 should be aligned with the slot 19a of key shaped apertures 18 on vertical posts 10. Once aligned, screws/bolts 52 can be inserted through the circular aperture 51 on structural beams 50 and continue through the slot 19a of key shaped apertures 18 on vertical posts 10 so that structural beam 50 is in contact with vertical post 10 and the screw/bolt 52 protrudes through the slot 19a and past the vertical post 10. To removeably lock the beams 50 to the vertical posts 10, the nut 53 can be fastened to the screw/bolt 52 as seen in FIGS. 14. This process can be repeated until the structural beams 50 are remeoveably attached to the vertical posts 10. Referring to FIG. 15, the assembled shelving unit 3 is shown including four vertical posts 37. Each vertical post 37 has a pair of legs 39, 40 perpendicular to one another as shown in FIG. 17. A plurality of structural beams 35 and horizontal shelving members 12 extend between the pairs of legs 39, 40 on vertical posts 37 and may be attached in a manner to be described below. Structural beam 35 is provided with fingers 36 as seen in FIG. 17. The fingers 36 enable structural beam 35 to be associated with the vertical post 37. A pair of fingers 36 are located at each end of structural beam 35. The vertical location of each pair of fingers 36 is relative to the vertical distance between the slots 38 on legs 39 and 40 on vertical post 37. The horizontal location of fingers 36 on structural beams 35 also enable a corner fit between structural beams 35 as shown in FIG. 17. As seen in FIG. 17, the vertical posts 37 are provided with a plurality of slots 38 on legs 39 and 40, along with fingers 36 enable beams 35 to be removeably assembled to the vertical posts 37. As seen in FIG. 17, the framework is assembled with the vertical posts 37 and are orientated in a way such that the legs 39, 40 of each post 37 are aligned with legs 39, 40 of the remaining 3 posts to form a rectangular shape within the legs 39, 40 of all four posts 37. The structural beams 35 can then be removeably associated to the vertical posts 37 such as seen in FIG. 17. In operation, the fingers 36 are inserted through the respective slots 38 such that the bottom portion of the finger 36 pass through the top portion of the slot 38. The beams 35 become secured to vertical posts 37 when the edge 41 contacts the top of the slot 38 as seen in FIG. 17. This same assembly can be repeated until all structural beams 35 are removeably associated to the vertical posts 37. It may thus be seen that the objects of the present inventions set forth as well as those made apparent from the foregoing description, are officially obtained. While the preferred embodiments of the invention have been set for purposes of disclosure, modification of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>This invention relates in general to a shelving unit and more particularly to the structural beams in the shelving unit. Several products are similar to this product in that they rely on beams affixed to posts to form a rigid shell that in turn supports shelf members. The same problems and disadvantages associated with prior art disclosed in the original CARGO-RACK patent application nonetheless exist for purposes of this Continuation-in-Part application. Generally, the disadvantages related to inadequate load bearing capacities, over-sized units, multiplicity of components required for assembly along with potential instability of shelving units. | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>The shelving unit of the present invention preferably includes at least 4 vertical post members mutually spaced from one another. The structural beams are orientated perpendicular to vertical post members and removeably associated therewith taking the form of a parallelogram. The shelving unit is complete when shelf members are removeably associated to the structural beam and vertical post framework. Acknowledging the same problems and disadvantages associated with the prior art as disclosed in the original CARGO-RACK patent application Ser. No. 10/715000, this Continuation-in-Part CARGO-RACK patent application serves to provide additional assemblies discovered by the inventors to associate the structural beams to the vertical posts. Incorporating these additional methods provides additional means to easily assemble the shelving unit while still minimizing cost per unit, maximizing strength to material weight ratio, and ensuring that cargo will be adequately supported. These features will become more clearly understood upon consideration of the following detailed description and accompanying drawings. For purposes of clarity, we are herein incorporating by reference the following portions of the parent application filed on Nov. 17, 2003, pages 6-9, and any other parts of the Parent Application that provide support for certain claims of this case: “The recessed structural beams 2 include a rib 8 , with a recessed flange 6 , and a return flange 4 as seen in FIG. 5 . The rib 8 , recessed flange 6 , and return flange 4 terminate in a vertical edge of the recessed structural beam 2 . The recessed flange 6 is chamfered at the ends of its base 7 in order to enable assembly to appear as seen in FIG. 4 once it has moved along the dashed lines to engage the legs 20 , 21 of the vertical post 10 .” “The recessed structural beams 30 combine a recessed flange 31 and a return flange 32 as seen in FIG. 13 . The recessed flange 31 and return flange 32 terminate in a vertical edge of the recessed structural beam 30 . The recessed flange 31 is chamfered at its base 33 in order to enable assembly much in the same way as recessed flange 6 is chamfered at its base 7 on recessed structural beams 2 as shown in FIG. 4 once it has moved along the dashed lines to engage the legs 20 , 21 of the vertical post 10 .” “The standard structural beams 25 includes a rib 26 formed between an angled standard flange 27 and an angled return flange 28 as seen in FIG. 11 . The rib 26 , angled standard flange 27 , and angled return flange 28 terminate in a vertical edge of the standard structural beam 25 . The angled standard flange 27 is chamfered in order to enable standard structural beam assembly to appear as seen in FIG. 10 once it has moved along the dashed lines to engage the legs 20 , 21 of vertical post 10 .” “Once structural beams 2 , 25 , or 30 are associated to vertical post 10 , it is then possible to removeably associate shelf member 12 to the unit thereby completing the shelving unit 1 .” | 20040413 | 20070807 | 20050519 | 79329.0 | 1 | PUROL, SARAH L | CARGO RACK | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,823,220 | ACCEPTED | Medical device system | A first portable medical device is adapted for use in an interlocking system for interlocking the first medical device to a second medical device. The first device includes a housing having opposite sides, a selective element, a blocking element, and an optional clamp mechanism. At least one of the opposite sides includes a matable element to detachably attach a second medical device. The selective element restricts the attachment of the second device to only one side of the first device. The blocking element prevents a third medical device from attaching to the first and second devices once the first and second devices are attached. The clamp restricts the attachment of the second device to only one side of the first device when the clamp is attached to a support member. The clamp permits slide-ratcheting axial movement of a clamp shaft. | 1. A system for interlocking a plurality of portable medical devices in a side-by-side relationship, the system comprising: the plurality of medical devices including a first medical device and a second medical device; the first medical device including a housing having opposite sides, at least one of the opposite sides including a matable element; the second medical device including a housing having opposite sides, at least one of the opposite sides of the housing of the second medical device including a matable element for detachably interconnecting to the matable element of the first medical device and attaching the first and second medical devices; and wherein at least one of the medical devices includes a selective means for restricting the attachment of the second medical device to only one of the opposite sides of the first medical device housing. 2. The system of claim 1, wherein the at least one of the medical devices is provided with only a single matable element, constituting the selective means. 3. The system of claim 1, wherein the first medical device is provided with two matable elements, one matable element being located on each of the opposite sides of the first medical device housing. 4. The system of claim 3, wherein the selective means includes a locking element which restricts attachment of the second medical device to the first medical device to only one of the opposite sides of the first medical device once the first medical device is attached to a support member. 5. The system of claim 4, wherein the first medical device includes a clamp mechanism for mounting at least one medical device to a support member. 6. The system of claim 5, wherein the clamp mechanism has a hole therein for slidably receiving the locking element, the locking element adapted to apply force on a component of the medical device when the clamp body is affixed to a support member. 7. The system of claim 5, wherein the clamp mechanism has a slide-ratcheting means for permitting a user to close the clamp mechanism about the support member by application of linear force to the clamp mechanism. 8. The system of claim 1, wherein at least one of the medical devices includes a blocking means for preventing a third medical device from attaching to either the first or second medical devices once the first and second medical devices are attached. 9. The system of claim 1, wherein at least one of the medical devices includes a latch element which detachably locks the first and second medical devices together once the first and second medical devices are attached. 10. The system of claim 9, wherein a release element is operatively associated with the latch element, the release element permitting a user to selectively disengage the latch element. 11. The system of claim 9, wherein the first medical device includes the latch element, the first medical device is provided with two matable elements where one matable element is located on each of the opposite sides of the first medical device housing, and wherein the latch element extends from the first medical device housing side that is not adjacent the attached second medical device and is secured in a position which prevents a third medical device from being added to the first medical device once the first and second medical devices are attached. 12. The system of claim 1, wherein the first and second medical devices each include a transceiver, the transceivers being aligned for communication between the medical devices once the first and second medical devices are attached. 13. A system for interlocking a plurality of portable medical devices in a side-by-side relationship, the system comprising: the plurality of medical devices including a first medical device and a second medical device; the first medical device including a housing having opposite sides, at least one of the opposite sides including a matable element; the second medical device including a housing having opposite sides, at least one of the opposite sides of the housing of the second medical device including a matable element for detachably interconnecting to the matable element on the first medical device housing and attaching the first and second medical devices; and wherein at least one of the medical devices includes a blocking means for preventing a third medical device from attaching to either the first or second medical device once the first and second medical devices are attached. 14. The system of claim 13, wherein the at least one of the medical devices is provided with only a single matable element, constituting the blocking means. 15. The system of claim 13, wherein the first medical device is provided with two matable elements, a first matable element being located on one of the first medical device housing sides and a second matable element being located on the first medical device housing opposite side. 16. The system of claim 15, wherein the blocking means includes a blocking element associated with the first medical device which blocks attachment of a third medical device to the first medical device once the first and second medical devices are attached. 17. The system of claim 13, wherein at least one of the medical devices includes a latch element which detachably locks the first and second medical devices together once the first and second medical devices are attached. 18. The system of claim 17, wherein a release element is operatively associated with the latch element, the release element permitting a user to selectively disengage the latch element. 19. The system of claim 17, wherein the first medical device includes the latch element, the first medical device is provided with two matable elements where one matable element is located on each of the first medical device housing opposite sides, and wherein the blocking means includes the latch element which extends from the first medical housing side that is not adjacent the attached second medical device, the latch element being secured in a position which prevents a third medical device from being added to the first medical device once the first and second medical devices are attached. 20. The system of claim 13, wherein the first and second medical devices each include a transceiver, the transceivers being aligned for communication between the medical devices once the first and second medical devices are attached. 21. A clamp mechanism for mounting a medical device to a support member, comprising: a clamp body defining a first jaw, a second jaw and an opening therebetween adapted to receive a support member; a clamp shaft including a forward end for extending into the opening, a rearward end, and an intermediate portion having a longitudinal axis and being mounted for axial movement on the first jaw of the clamp body; ratchet and pawl means operatively interposed between the intermediate portion of the clamp shaft and the clamp body, the ratchet and pawl means comprising ratchet teeth and a pawl; biasing means for yieldingly urging the pawl and ratchet teeth into engagement with a biasing force; and the biasing means, the ratchet teeth, and the pawl being configured and arranged to normally resist axial movement of the clamp shaft in a direction away from the opening and, upon application of an axial force to the clamp shaft sufficient to overcome the biasing force of the biasing means, to permit slide-ratcheting axial movement of the clamp shaft in a direction toward the opening. 22. A clamp mechanism in accordance with claim 21, wherein the clamp body has a hole therein for slidably receiving a locking element, the locking element adapted to apply force on a component of the medical device when the clamp body is affixed to a support member. 23. A clamp mechanism in accordance with claim 21, wherein the first jaw and the second jaw are stationary. 24. A clamp mechanism in accordance with claim 21, wherein the first jaw of the clamp body has a clamp shaft receiving bore therein for slidably receiving the clamp shaft. 25. A clamp mechanism in accordance with claim 21, wherein the ratchet teeth are external threads formed on the intermediate portion of the clamp shaft, and wherein the threads have a forward lead flank and a rear load flank, the leading flank extending rearward to form an acute angle with a longitudinal axis of the clamp shaft and the load flank extending perpendicular to the longitudinal axis of the clamp shaft. 26. A clamp mechanism in accordance with claim 21, further comprising a release mechanism for overcoming the biasing force of the biasing means and disengaging the pawl and ratchet teeth, thereby permitting axial movement of the clamp shaft in the direction away from the opening. 27. A clamp mechanism in accordance with claim 26, wherein the release mechanism and the pawl means are a unitary body. 28. A clamp mechanism in accordance with claim 26, wherein the first jaw has a release bore therein and the release mechanism is an elongated pin slidably mounted in the release bore. 29. A clamp mechanism in accordance with claim 26, wherein the release mechanism has an adjustment slot extending therethrough for receiving the clamp shaft, the ratchet portion of the clamp shaft having threads with a major diameter and the adjustment slot having a length greater than the major diameter of the threads on the clamp-shaft, the pawl being a portion of a wall of the adjustment slot having a thread thereon for matingly engaging the ratchet portion of the clamp shaft. 30. A clamp mechanism in accordance with claim 21, further comprising a hand knob attached to the second end of the clamp shaft. 31. A clamp mechanism in accordance with claim 30, further comprising a clutch mechanism operatively interposed between the hand knob and the clamp shaft, the clutch mechanism being adapted to prevent overtightening of the clamp shaft against a pole beyond a given torque value. 32. A clamp mechanism in accordance with claim 21, wherein the clamp mechanism is adapted to be rotatably associated with the medical device. 33. A clamp mechanism in accordance with claim 32, wherein the clamp mechanism includes a pivot latch adapted to selectively lock the clamp mechanism in a select one of a plurality of rotational positions with respect to the medical device. 34. A first portable medical device adapted for use in an interlocking system for interlocking the first medical device to a second medical device in a side-by-side relationship, the first medical device comprising: a housing having opposite sides, at least one of the opposite sides including a matable element adapted to detachably interconnect a second medical device to the first medical device; and a selective means for restricting the attachment of the second medical device to only one of the opposite sides of the first medical device housing. 35. The medical device of claim 34, wherein the first medical device is provided with only a single matable element, constituting the selective means. 36. The medical device of claim 35, further comprising a pump mechanism located opposite the single matable element on the housing. 37. The medical device of claim 34, wherein the first medical device is provided with two matable elements, one matable element being located on each of the housing opposite sides. 38. The medical device of claim 37, further comprising two pump mechanisms, one pump mechanism being located on each of the housing opposite sides. 39. The medical device of claim 37, wherein the selective means includes a locking element which restricts attachment of the second medical device to the first medical device to only one of the opposite sides of the first medical device once the first medical device is attached to a support member. 40. The medical device of claim 39, wherein the first medical device includes a clamp mechanism for mounting at least one medical device to a support member. 41. The medical device of claim 40, wherein the clamp mechanism has a hole therein for slidably receiving the locking element, the locking element adapted to apply force on a component of the first medical device when the clamp body is affixed to a support member. 42. The medical device of claim 40, wherein the clamp mechanism has a slide-ratcheting means for permitting a user to close the clamp mechanism about the support member by application of linear force to the clamp mechanism. 43. The medical device of claim 34, wherein the first medical device includes a blocking means for preventing a third medical device from attaching to either the first or second medical devices once the first and second medical devices are attached. 44. The medical device of claim 34, wherein the first medical device includes a latch element which detachably locks the first and second medical devices together once the first and second medical devices are attached. 45. The medical device of claim 44, wherein a release element is operatively associated with the latch element, the release element permitting a user to selectively disengage the latch element. 46. The medical device of claim 44, wherein the first medical device includes the latch element, the first medical device is provided with two matable elements where one matable element is located on each of the first medical device housing opposite sides, and wherein the latch element extends from the first medical device housing side that is not adjacent the attached second medical device and is secured in a position which prevents a third medical device from being added to the first medical device once the first and second medical devices are attached. 47. The medical device of claim 34, wherein the first medical device includes a transceiver, the transceiver being adapted to communicate with a corresponding transceiver on the second medical device, the transceiver and corresponding transceiver being aligned for communication between the medical devices once the first and second medical devices are attached. 48. A first portable medical device adapted for use in an interlocking system for interlocking the first medical device to a second medical device in a side-by-side relationship, the first medical device comprising: a housing having opposite sides, at least one of the opposite sides including a matable element adapted to detachably interconnect a second medical device to the first medical device; and a blocking means for preventing a third medical device from attaching to the first medical device once the first and second medical devices are attached. 49. The medical device of claim 48, wherein the first medical device is provided with only a single matable element, constituting the blocking means. 50. The medical device of claim 49, further comprising a pump mechanism located opposite the single matable element on the housing. 51. The medical device of claim 48, wherein the first medical device is provided with two matable elements, one matable element being located on each of the opposite sides of the first medical device housing. 52. The medical device of claim 51, further comprising two pump mechanisms, one pump mechanism being located on each of the first medical device housing opposite sides. 53. The medical device of claim 51, wherein the blocking means includes a blocking element associated with the first medical device which blocks attachment of a third medical device to the first medical device once the first and second medical devices are attached. 54. The medical device of claim 51, wherein the first medical device includes a latch element which detachably locks the first and second medical devices together once the first and second medical devices are attached. 55. The medical device of claim 54, wherein a release element is operatively associated with the latch element, the release element permitting a user to selectively disengage the latch element. 56. The medical device of claim 54, wherein the first medical device is provided with two matable elements where one element is located on each of the first medical device housing opposite sides, and wherein the blocking means includes the latch element which extends from the first medical device housing side that is not adjacent the attached second medical device, the latch element being secured in a position which prevents a third medical device from being added to the first medical device once the first and second medical devices are attached. 57. The medical device of claim 48, wherein the first medical device includes a transceiver, the transceiver being adapted to communicate with a corresponding transceiver on the second medical device, the transceiver and corresponding transceiver being aligned for communication between the medical devices once the first and second medical devices are attached. 58. A clamp mechanism for mounting a medical device to a support member, comprising: a clamp body defining a first jaw, a second jaw and an opening therebetween adapted to receive a support member; a clamp shaft including a forward end for extending into the opening, a rearward end, and an intermediate portion having a longitudinal axis and being mounted for axial movement on the first jaw of the clamp body; ratchet and pawl means operatively interposed between the intermediate portion of the clamp shaft and the clamp body, the ratchet and pawl means comprising ratchet teeth and a pawl; biasing means for yieldingly urging the pawl and ratchet teeth into engagement with a biasing force; the biasing means, the ratchet teeth, and the pawl being configured and arranged to normally resist axial movement of the clamp shaft in a direction away from the opening; and a release mechanism for overcoming the biasing force of the biasing means and disengaging the pawl and ratchet teeth, thereby permitting axial movement of the clamp shaft in the direction away from the opening; wherein the release mechanism and the pawl means are a unitary body. 59. A clamp mechanism in accordance with claim 58, wherein the ratchet teeth are external threads formed on the intermediate portion of the clamp shaft. 60. A clamp mechanism in accordance with claim 59, wherein the threads have a forward lead flank and a rear load flank, the leading flank extending rearward to form an acute angle with a longitudinal axis of the clamp shaft and the load flank extending perpendicular to the longitudinal axis of the clamp shaft. 61. A clamp mechanism in accordance with claim 58, wherein the first jaw of the clamp body has a clamp shaft receiving bore therein for slidably receiving the clamp shaft. 62. A clamp mechanism in accordance with claim 58, wherein the first jaw has a release bore therein and the release mechanism is an elongated pin slidably mounted in the release bore. 63. A clamp mechanism in accordance with claim 58, wherein the release mechanism has an adjustment slot extending therethrough for receiving the clamp shaft, the ratchet portion of the clamp shaft having threads with a major diameter and the adjustment slot having a length greater than the major diameter of the threads on the clamp shaft, the pawl being a portion of a wall of the adjustment slot having a thread thereon for matingly engaging the ratchet portion of the clamp shaft. 64. A clamp mechanism in accordance with claim 58, wherein the release mechanism includes a release lever pivotally mounted to the first jaw. 65. A clamp mechanism in accordance with claim 64, wherein the release mechanism including the release lever and pawl means are located on the exterior of the first jaw. 66. A clamp mechanism in accordance with claim 58, further comprising a hand knob attached to the second end of the clamp shaft. 67. A clamp mechanism in accordance with claim 66, further comprising a clutch mechanism operatively interposed between the hand knob and the clamp shaft, the clutch mechanism being adapted to prevent overtightening of the clamp shaft against a pole beyond a given torque value. 68. A clamp mechanism in accordance with claim 58, wherein the clamp mechanism is adapted to be rotatably associated with the medical device. 69. A clamp mechanism in accordance with claim 68, wherein the clamp mechanism includes a pivot latch adapted to selectively lock the clamp mechanism in a select one of a plurality of rotational positions with respect to the medical device. 70. A medical device in accordance with claim 47, wherein the transceivers are adapted to communicate wirelessly to with other. 71. A medical device in accordance with claim 70, wherein the transceivers are infrared transceivers. 72. A medical device in accordance with claim 1, wherein the matable element on the first medical device includes a ramped portion allowing the matable element on the first medical device to mate with the matable element on the second medical device when said matable elements are not precisely aligned. 73. A medical device in accordance with claim 1, wherein the matable element on the second medical device includes a tapered portion allowing the matable element on the first medical device to mate therewith when said matable elements are not precisely aligned. 74. A medical device in accordance with claim 1, wherein the matable elements are corresponding male T-slides and female T-slots. 75. A medical device in accordance with claim 13, wherein the matable element on the first medical device includes a ramped portion allowing the matable element on the second medical device to mate therewith when said matable elements are not precisely aligned. 76. A medical device in accordance with claim 13, wherein the matable element on the second medical device includes a tapered portion allowing the matable element on the first medical device to mate therewith when said matable elements are not precisely aligned. 77. A medical device in accordance with claim 13, wherein matable elements are corresponding male T-slides and female T-slots. 78. A medical device in accordance with claim 34, wherein the matable element includes a ramped portion allowing the matable element to detachably interconnect a second medical device to the first medical device when the second medical device and first medical device are not precisely aligned. 79. A medical device in accordance with claim 34, wherein the matable element includes a tapered portion allowing the matable element to detachably interconnect a second medical device to the first medical device when the second medical device and first medical device are not precisely aligned. 80. A medical device in accordance with claim 34, wherein the matable element is a T-slot. 81. A medical device in accordance with claim 48, wherein the matable element includes a ramped portion allowing the matable element to detachably interconnect a second medical device to the first medical device when the second medical device and first medical device are not precisely aligned. 82. A medical device in accordance with claim 48, wherein the matable element includes a tapered portion allowing the matable element to detachably interconnect a second medical device to the first medical device when the second medical device and first medical device are not precisely aligned. 83. A medical device in accordance with claim 48, wherein the matable element is a T-slot. | CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of U.S. patent application Ser. No. 10/696,830, filed Oct. 30, 2003. BACKGROUND OF THE INVENTION The present invention generally relates to the field of medical devices, and more particularly to the field of point of care medical devices including but not limited to infusion pumps, monitors, and diagnostic equipment. The invention provides a portable point of care system that includes one or more medical devices mountable on a pole stand, bedrail or other supporting structure in close proximity to a patient. The invention includes means and methods for interlocking the medical devices together, preventing undesirable arrangements and combinations of medical devices, mounting the medical devices on the main supporting structure, and automatically providing wireless communication between the medical devices. In modern medical practice a variety of diagnostic and therapeutic devices are used, sometimes to such a degree that floor and shelf space near the patient's bedside is at a premium. One known solution to the problem of mounting medical devices is the use a pole stand. Often such pole stands have wheels for the convenience of the patient or medical personnel in moving the devices where they are needed, but wheeled pole stands can become unbalanced upon, for example, crossing thresholds or exiting elevators. Some manufacturers have mounted a central management unit and infusion pump modules in a vertically stacked configuration on a pole stand, as disclosed in U.S. Pat. Nos. 4,756,706 and 4,898,578. Vertically stacked configurations can make identification, routing and management of the associated intravenous (IV) tubes confusing and difficult. Manufacturers also have interlocked interchangeable independently functioning single channel pumps in a horizontal arrangement for attachment at a particular vertical location on a pole stand, as disclosed in U.S. Pat. No. 5,431,509. U.S. Pat. Nos. 5,713,856; 5,941,846 and 5,601,445 disclose a central control unit and a plurality of horizontally arranged detachable pump and/or sensor modules. Other manufacturers have developed multiple channel pumps, as disclosed in U.S. Pat. No. 5,378,231 and Des. 367,528. However, in the vast majority of applications a single channel pump or single pump module will suffice to meet the caregiver's needs, and customers generally are not inclined to pay the substantial premium needed to cover the manufacturing cost of a multiple channel pump or an elaborate interlocking means. Thus, there is a need for an improved system of medical devices. A primary objective of the present invention is the provision of an improved system of interlockable portable medical devices that only allows two medical devices to be joined together. Another objective of the present invention is the provision of an improved system of interlockable portable medical devices. A further objective of the present invention is the provision of an improved clamp mechanism, for mounting a medical device to a support member, which restricts the attachment of a second medical device to only one side of a first medical device when the clamp mechanism is attached to a support member. A still further objective of the present invention is the provision of an improved clamp mechanism that permits slide-ratcheting axial movement of the clamp shaft. These and other objects will be apparent to those skilled in the art. SUMMARY OF THE INVENTION A first portable medical device is adapted for use in an interlocking system for interlocking the first medical device to a second medical device. The first device includes a housing having opposite sides, a selective element, a blocking element, a clamp mechanism, and wherein at least one of the opposite sides includes a first matable element to detachably interconnect a second medical device to the first medical device. The selective element restricts the attachment of the second device to only one of the opposite sides of the first device. The blocking element prevents a third medical device from attaching to either the first or second device once the first and second devices are attached. The clamp mechanism restricts the attachment of the second device to only one side of the first device when the clamp mechanism is attached to a support member. The clamp mechanism also permits slide-ratcheting axial movement of a clamp shaft. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front perspective view of a medical device adapted for use in a medical device system according to the present invention; FIG. 1A is a front perspective view of another medical device adapted for use in a medical device system according to the present invention; FIG. 2 is a rear perspective view of one embodiment of the medical device system of this invention wherein two medical devices are joined together in side-by-side relationship; FIG. 2A is a rear perspective view of another embodiment of the medical device system of this invention wherein two medical devices are joined together in side-by-side relationship; FIG. 3 is an exploded perspective view of a clamping mechanism of the present invention; FIG. 3A is a cross sectional side view of the clamping mechanism of the present invention taken along line 3A-3A in FIG. 3; FIG. 4 is a partial rear exploded perspective view of the device of FIG. 2A; FIG. 5 is a partial front exploded perspective view of the device of FIG. 2A; FIG. 5A is a partial front exploded perspective view of the device of FIG. 1, which is also the device on the right when viewed as in FIG. 2; and FIG. 6 is an exploded perspective view of an alternative clamping mechanism of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) In the description and figures, components that are similar or substantially identical in function or structure are designated with similar or identical reference numerals. The medical device system 10 (FIG. 2), 10A (FIG. 2A) of the present invention includes a plurality of portable medical devices 12 (FIG. 1) and 14 (FIG. 1A) or 14L and 14R (FIG. 2A) that are capable of being detachably interlocked together. Devices 12, 14, 14L, or 14R can be devices for performing similar tasks or devices for performing different tasks as described below. For the sake of brevity the devices 14L, 14R, which are labeled to indicate their respective positions on the left and right of the system 10A when viewed from the front, are sometimes referenced in a generic sense by reference numeral 14. In the context of the present invention, the term “medical device” includes without limitation a device that acts upon a cassette, reservoir, vial, syringe, or tubing to convey medication or fluid to or from a patient (for example, an infusion pump, a patient controlled analgesia (PCA) or pain management medication pump, or a suction pump), a monitor for monitoring patient vital signs or other parameters, or a diagnostic device. For the purpose of exemplary illustration only, the medical devices 12, 14, 14L, and 14R are all disclosed as infusion pumps. More particularly, the medical device 12 can be a single channel infusion pump and the medical devices 14L and 14R can be dual channel infusion pumps. The pumps 12 and 14 have housings 16 and 16A respectively. Each housing 16, 16A includes generally opposite side walls 17L, 17R and generally opposite back and front walls 18B, 18F. A user interface touch screen 20 is mounted in the front wall of housing 16, 16A so as to be visible and accessible from the front of the device. As best seen in FIGS. 2 and 2A, at least one, and more preferably both, of the medical devices or pumps 12, 14 has a releasable clamping mechanism 22 attached thereto for detachably mounting the device 12 or 14 to a support structure or member, such as a tabletop edge or pole 24. In the context of this invention, a “pole” should be understood to include without limitation an elongated bar, rail, tubular member, beam or pin on a pole stand, bed, wall or other structure for supporting the medical device. The pole 24 can be configured and oriented in a variety of known ways, including without limitation as a bed rail extending in a generally horizontal direction or as an upright tubular member extending in a generally vertical direction on a pole stand. For the sake of brevity only the clamping mechanism 22 on the pump 12 is described below, but the clamping mechanism 22 on pump 14, if provided, can be substantially identical. As best seen in FIGS. 2, 2A, 3 and 3A, the clamping mechanism 22 of the present invention has a substantially rigid clamp body 26 that is pivotally and preferably removably attached to the pump housing 16 and includes a pole-receiving slot 28 for receiving the pole 24. The clamp body 26 defines generally opposing first and second jaws 30, 32 that at least partially surround the pole-receiving slot 28. One skilled in the art will appreciate that many different clamp body shapes can be utilized without detracting from the invention, including without limitation a generally L-shaped, U-shaped, J-shaped, G-shaped or. C-shaped clamp body. A clamp shaft 34 is movably mounted on the first jaw 30. The clamp shaft 34 has opposite ends 36, 38 and a ratchet portion 40 therebetween. The first jaw 30 has a clamp shaft receiving hole 42 formed therein, and more preferably therethrough, for receiving bushings 43 and the ratchet portion 40 of the clamp shaft 34. The distal end 36 of the clamp shaft 34 extends from the first jaw 30 toward the second jaw 32. A pressure pad 44 connects, or more preferably attaches, to the distal end 36. The proximal end 38 of the clamp shaft 34 has displacement means 46 connected thereto for selectively moving the clamp shaft 34 axially and applying a torque to the clamp shaft 34. While one skilled in the art will appreciate that the displacement means 46 for moving or turning the clamp shaft could include a hydraulic or pneumatic cylinder, electric stepper motor, or other powered displacement devices, a simple manual hand knob 48 can be connected to the clamp shaft 34, preferably to the proximal end 38 on the opposite side of the first jaw 30. A clutch mechanism 50 can be operatively interposed between the knob 48 and the clamp shaft 34. The clutch mechanism 50 can be a ratchet type or any other known type for preventing the tightening torque applied to the clamp shaft from exceeding a predefined torque limit. Individuals manually installing the pump 12, 14 on the pole 24 will have different strength capabilities for applying torque to the hand knob 48. The clutch mechanism 50 insures that a consistent clamping force is applied to the pole 24 and prevents overtightening, which insures that the torque required to release the clamp mechanism from the pole is consistent and well within the capabilities of most individuals. The ratchet portion 40 of the clamp shaft 34 has ratchet teeth. Preferably the ratchet teeth comprise external threads 51. The threads 51 can be any type of helical threads without detracting from the invention, but more preferably the threads 51 are pull-type buttress threads. As is well known in the mechanical arts, buttress threads have a pressure, thrust or load flank that is nearly perpendicular (with less than ten, and more preferably about five to seven, and typically about five degrees inclination allowed for cutter clearance) to the thread axis of the shaft and a clearance flank, lead flank or thread angle that is about fifty to forty-five degrees. Preferably, the buttress threads utilized in this invention have a pressure flank 52 directed toward the proximal end 38 of the clamp shaft 34 and a lead flank 54 directed toward the distal end 36 of the clamp shaft 34. A selectively releasable positioning means or travel control means 56 is movably mounted on the clamp body 26. The travel control means 56 includes a release button 58 that has at least one pawl 59 adapted to matingly engage the threads 51 on the clamp shaft 34 and means for biasing the pawl 59 into engagement with the threads 51. The release lever or button 58 and pawl 59 are shown as a unitary body; however, it will be understood that the release lever 58 and pawl 59 may be provided as separate pieces. The release button 58 is movably mounted in a hole 60 in the first jaw 30. The hole 60 intersects the clearance hole 42 as shown. The release button 58 is preferably an elongated pin with a slot 62 extending transversely therethrough. The slot 62 receives the clamp shaft 34 and has a length greater than the major diameter of the threads 51 on the clamp shaft 34. The width of the slot 62 is slightly greater than the major diameter of the threads 51. The slot 62 includes the pawl 59 as a portion thereof and has a thread on a wall thereof for matingly engaging the ratchet portion 40 of the clamp shaft 34. The pawl 59 is normally biased into mating engagement with the ratchet portion 40 of the clamp shaft 34 by a biasing means 64 (such as a spring or other similar device) operatively interposed between the release button 58 and the first jaw 30. In operation, the travel control means 56 is configured and arranged to normally resist axial movement of the clamp shaft 34 in a direction away from the pole-receiving slot 28. The travel control means 56 also permits a user to apply an axial force to the clamp shaft 34 sufficient to overcome the biasing force of the biasing means 64, to permit slide-ratcheting axial movement of the clamp shaft 34 in a direction toward the opening or pole-receiving slot 28. Alternatively, in some applications it is desirable to prevent slide-ratcheting axial movement of the clamp shaft 34 if axial force is inadvertently applied to the clamp shaft 34. In this case the biasing means 64 is selected to provide sufficient spring force to prevent normal user force on the clamp shaft 34 from causing slide-ratcheting axial movement of the clamp shaft 34 without the user also deactivating the travel control means 56. A biasing means 66 (such as a spring or other similar device) is operatively interposed between the first jaw 30 and a ledge 68 on the clamp shaft 34. A bellows element 70 encloses the clamp shaft 34 and biasing means 66. The bellows element 70 protects a user from contacting the clamp shaft 34 and biasing means 66 moving parts. As best seen in FIGS. 3 and 4, the clamp mechanism 22 is adapted to be rotatably associated with the medical device housing 16A or 16 (not shown). The clamp mechanism 22 includes a clamp lug 72 which rotationally mates with a housing lug 74. The clamp lug 72 includes extended ear elements 76 that correspond in shape and size to ear recesses 78 in the housing lug 74. The ear recesses 78 receive the extended ear elements 76. Once the clamp mechanism 22 is rotated, the clamp lug 72 mates with housing lug 74 to removably secure the clamp mechanism 22 to the medical device housing 16A. A pivot latch 80 is movably mounted on the clamp body 26. The pivot latch 80 permits an operator to selectively lock the clamp mechanism 22 in a select one of a plurality of rotational positions with respect to the housing 16A. These rotational positions are defined by the recesses 82 of the housing lug 74. The pivot latch 80 is normally biased into mating engagement with the recesses 82 of the housing lug 74 by a biasing means 84 (such as a spring or other similar device) operatively interposed between the pivot latch 80 and the clamp body 26. As best seen in FIGS. 3-5, the clamp body 26 has a hole 86 therein for slidably receiving a locking element 88. As will be discussed in greater detail below, the locking element 88 applies force on a component of the medical device 14 when the clamp body 26 is affixed to a support member 24 (FIG. 2A). As shown, the locking element 88 includes a support contact element 90 that contacts a support member 24 and is connected to a transfer pin 92 for locking the selected component of the medical device 14 to a restricted range of motion, and a main body 93 extending between the support contact element 90 and the transfer pin 92. Although the main body 93, support contact element 90, and transfer pin 92 are shown as a unitary member, one skilled in the art will appreciate that they can be separate components without detracting from the invention. For example, the contact element 90 and transfer pin 92 can be a unitary member that is movable with respect to the main body 93 or all three parts can be separate components. The transfer pin 92 is normally biased toward the pole-receiving slot 28 and away from the housing 16A by a biasing means 94 (such as a spring or other similar device) operatively interposed between the main body 93 and the clamp body 26. A washer 95 provides a seat for the biasing means 94 and retains the main body 93 in the opening 86 when a retaining ring 97 is installed in a retaining groove 99 in the opening 86. The washer 95 has a hole 101 through which the transfer pin 92 slidably extends. Thus when the clamp body 26 is mounted on the housing 16A the biasing means 94 is also operatively interposed between the housing 16A and the main body 93. Other designs of locking element are contemplated. For instance, the locking element 88 could apply only a frictional force to the selected component of the medical device 14. As best seen in FIGS. 2A, 4 and 5, the medical device 14 includes a first matable element 102 positioned on the side wall 17R and a second matable element 104 positioned on the side wall 17L. The first matable element 102 is formed as a female T-slot in the housing 16A. The second matable element 104 is formed as a male T-slide attached to the housing 16A. Alternatively, the first matable element 102 is formed as a female dovetail in the housing 16A, and the second matable element 104 is formed a male dovetail attached to the housing 16A. Another alternative embodiment is to merely provide at least one of the opposite sides of the medical devices 14R, 14L with a matable element for detachably interconnecting to the matable element of the other medical device and attaching the first and second medical devices together. In other words, the unused matable elements in FIG. 2A, 4, 5 and 5A could be removed or omitted. The first matable element 102 includes a ramped portion 103 at its upper end. The ramped portion 103 allows for a greater degree of freedom when a user initially mates the first matable element 102 to the second matable element 104. Likewise, the second matable element 104 includes a tapered portion 105 at its lower end. The tapered portion 105 allows for a greater degree of freedom when a user initially mates the first matable element 102 to the second matable element 104. Without such ramped portion 103 and/or tapered portion 105, the first matable element 102 and second matable element 104 would need to be precisely aligned to properly mate together. Although it may differ in the clinical function or task it performs, with respect to its attachment or connectology features, the second medical device 14R is substantially identical to the first medical device 14L. The second medical device 14R includes second matable element 104 positioned on the side wall 17L for detachably interconnecting to the corresponding first matable element 102 of the first medical device 14L, attaching the first and second medical devices 14L, 14R. Once first and second medical devices 14L, 14R are joined, a latch element 106 extending through latch port 107 in the second medical device 14R side wall 17L mates with a corresponding latch notch 108 on the first medical device 14L side wall 17R. The latch element 106 detachably locks the first and second devices 14L, 14R together, and prevents the first and second matable elements 102 and 104 from being uncoupled. The latch element 106 is formed as a portion of a transfer plate 110. The transfer plate 110 extends through both side walls 17L and 17R of the device 14. The transfer plate 110 also includes a biasing means 111 (such as a spring or other similar device) operatively interposed between the transfer plate 110 and the housing 16A for laterally biasing the latch element 106 toward the latch notch 108. When the latch element 106 is engaged to a corresponding latch notch 108, the transfer plate 110 is slightly displaced relative to the housing 16A and the side walls 17L and 17R. This displacement causes a blocking element 112 of the transfer plate 110 to extend through a blocking port 114 in the second medical device 14R side wall 17L. When the blocking element 112 is extended, no additional medical device can be joined to the second medical device 14R. As best seen in FIGS. 1, 4 and 5, a latch post 109 is formed as a portion of a transfer plate 110. The latch post 109 is located along an upper edge of latch element 106 and mates with a corresponding undercut portion (not shown) located on the upper surface 113 of latch notch 108. In normal operation, the latch post 109 does not engage undercut portion of latch notch 108. However, in situations where a user is carrying two devices 12, 14 or 14L, 14R connected together by the handle of the right most device (14R), the latch post 109 prevents unintentional release of the latch element 106. Without latch post 109 and the undercut on surface 113, such an unintentional release would cause the left most device (14L or 12) to release out of attachment and to free fall. However, with the latch post 109, the latch element 106 mates with the corresponding undercut portion of latch notch 108 when the two devices (12 and 14R or 14L and 14R) are lifted only by the handle of the right most device (14R), and thus only slight relative movement is permitted between the two devices. As best seen in FIGS. 2A, 4 and 5, likewise, the blocking element 112 of the first medical device 14L abuts the second medical device 14R side wall 17L, and prevents the transfer plate 110 of the first medical device 14L from moving. Thus, the latch element 106 of the first medical device 14L is likewise prevented from moving, which will also block any additional medical device from being joined to the side wall 17L of first medical device 14L. Thus both blocking element 112 of the second medical device 14R and the latch element 106 of the first medical device 14L act as a blocking means for preventing a third medical device 12 or 14 from attaching to either the first or second medical device 14L or 14R once the first and second medical devices 14L, 14R are attached. This operation of a blocking means for preventing the connection of a third medical device 12 or 14 prevents the support surface 24 from bearing too much weight or from having an unbalanced weight placed on it sufficient to topple the support surface 24. For instance, the support surface 24 will typically be an IV stand. As shown in FIG. 2, two devices 14L, 14R (as explained below, device 12 could replace the device 14L) joined together place a somewhat unbalanced weight placed on the support surface 24. The two of the devices 12 and/or 14 joined together do not have a weight sufficient to topple the support surface 24. However, if a third medical device 12 or 14 was attached, there could be an unbalanced weight sufficient to topple the support surface 24. Thus, the blocking means prevents the user from the hazard of hanging too many connected medical device 12 or 14 from the support surface 24. When it is desired to uncouple the first and second medical devices 14L, 14R, a release element 116 on the second medical device 14R is actuated by the user. The release element 116 includes a tab 118 that permits the user to manually actuate the release element and base 120 extending from the tab 118 to contact the transfer plate 110 at a surface 122 thereof. The release element 116 also includes a biasing means 121 (such as a spring or other similar device) operatively interposed between the base 120 and the housing 16A for downwardly biasing the release element 116. When the release element 116 is actuated, the base 120 shifts the transfer plate 110, uncoupling the latch element 106 of the second medical device 14R from the corresponding latch notch 108 of the first medical device 14L. When this is done the user can uncouple the male matable element 104 of the second medical device 14R from the corresponding female matable element 102 of the first medical device 14L. As best seen in FIGS. 2A, 4 and 5, once a lone first medical device 14L is attached to a support structure 24, the support structure 24 presses on the support contact element 90 of the locking element 88. The pressure on the support contact element 90 displaces the entire locking element 88, thus moving the transfer pin 92 towards transfer plate 110. The transfer pin 92 engages a corresponding pin slot 124 portion of the transfer plate 110, securing the transfer plate 110 to a restricted range of motion. The pin slot 124 is shown as a hole in the transfer plate 110, but may also be formed as depression in the transfer plate 110. However, where other designs of locking element are utilized, the pin slot 124 may not be an essential component. For instance, it is contemplated that the locking element 88 could apply only a frictional force to the transfer plate 110 of the medical device 14. In this case, the pin slot 124 would not be needed. The pin slot 124 is oriented and arranged to receive the transfer pin 92, even in cases where two devices are joined (FIGS. 2 and 2A) and the device 14L is attached to the support structure 24. In this situation, the transfer plate 110 of device 14R is slightly displaced when the latch element 106 of device 14R is engaged to a corresponding latch notch 108 in either device 12 or 14L. Once the locking element 88 secures the transfer plate 110 to a restricted range of motion, the latch element 106 remains in an extended position through latch port 107 in the medical device 14L side wall 17L. The restricted extended latch element 106 of the first medical device 14L will block any additional medical device from being joined to the side wall 17L of first medical device 14L. Thus the locking element 88 fixing the latch element 106 operates as a selective means for restricting the attachment of the second medical device 14R to only the side wall 17R of first medical device 14L when first medical device 14L has been previously secured to support structure 24. Accordingly, it can be seen that when a separate first medical device 14L has been secured to support structure 24, any attachment of another device (e.g. second medical device 14R) can only be made to a predetermined side, i.e., side wall 17R, of first medical device 14L. This operation of a selective means for restricting the attachment of the second medical device 14R to only one side of the first medical device 14L lessens the potential for operator confusion when the second medical device 14R is being attached to a first medical device 14L that has been previously secured to support structure 24. For instance, where the first medical device 14L is a medical pump having defined first and second channels or pump mechanisms, when the first medical device 14L is attached by itself to support structure 24, there is little confusion as to where the first and second channels are located. Typically, the first channel will be located near side wall 17L and the second channel will be located near side wall 17R, with the user interface touch screen 20 disposed between the first and second channels. However, in instances where a second medical device 14R having defined third and fourth channels is later added to the first medical device 14L, placement of the second medical device 14R adjacent to the side wall 17L would increase the potential for user confusion. In such a case, the set of devices 14L, 14R would have a series of channels running from left to right in the following order: the third channel, the fourth channel, the first channel, and then the second channel. In order to prevent such confusion of channels in the use of the medical device system 10, 10A of the present invention, the selective means restricts the attachment of the second medical device 14R to only the side wall 17R of first medical device 14L, so that the channels running from left to right will have the following order: the first channel, the second channel, the third channel, and then the fourth channel. As best seen in FIGS. 1, 2 and 5, while the above system 10A for interconnecting medical devices is operable with any device 14 having the same interconnectable design, it is also designed to operate with a device 12 of system 10. As best understood in view of FIGS. 5 and 5A, the portable medical device 12 includes some features similar to the device 14, so that the devices 12 and 14 can be joined together; however, several components found in the device 14 (latch port 107, transfer plate 110, blocking port 114, and release element 116) are not included in the device 12. This design permits a user to distinguish between the two devices 12, 14, prevents undesirable arrangements and combinations, and also reduces the manufacturing cost as well as improving the reliability of the device 12 as compared to the device 14. Specifically, the device 12 includes a single matable element 102 on side wall 17R. The single matable element 102 is formed as a female T-slot slot for mating with corresponding male T-slide 104 from the device 14. The device 12 also includes a latch notch 108 for mating with corresponding latch element 106 from the device 14. However, unlike the device 14, the device 12 has no elements on its opposite side wall 17L for connecting to any other medical device 12 or 14. This lack of elements on one side wall 17L of device 12, allows the device 12 to prevent a second medical device 14 from being attached to the left of a first device 12, including when the first device 12 is secured to a support 24. Thus the lack of elements on one side wall 17L of device 12 acts as a selective means for restricting the attachment of a second medical device 14 to only one of the opposite sides of the first medical device 12. The lack of elements on one side wall 17L of first device 12 also prevents any device 12 or 14 from attaching to that side wall 17L of the first device 12. The latch notch 108 of the first device 12 also acts to activate the blocking element 112 on the second device 14 to prevent a third medical device 12 or 14 from being joined to the second device 14. Thus the lack of elements acts as a blocking means for preventing a third medical device 12 or 14 from attaching to either the first or second medical devices once the first and second medical devices 12, 14 are attached to one another. As best seen in FIGS. 1, 1A, 2 and 2A, each of the medical devices 12, 14 includes at least one transceiver 126. The medical device 12 is provided with one transceiver 126 located on the side 17R of the device 12 that has the matable element 102 positioned thereon. Each medical device 14 is provided with one transceiver 126 on each side 17L and 17R of the device 14. The transceiver 126 (not shown) positioned on side 17R of the first medical device 14L is aligned with the corresponding transceiver 126 positioned on side 17L of the second medical device 14R for communication between the medical devices 14L, 14R once the medical devices 14L, 14R are attached. The aligned transceivers 126 permit the medical devices 14L, 14R to communicate to one another. The transceivers 126 can be adapted for wireless communication or can physically contact each other once aligned. The transceivers 126 can be of various types, including but not limited to infrared, blue tooth, or radio frequency. For instance, the aligned transceivers 126 permit the medical devices 14L, 14R to synchronize activities and/or share data including but not limited to: time, patient information, drugs in use, pressure, flow data, total infusion volume, and historical logged information. As best seen in FIG. 6, an alternative clamping mechanism 222 of the present invention has a substantially rigid clamp body 226 that is pivotally and preferably removably attached to the pump housing 16 or 16A (not shown) and includes a pole-receiving slot 228 for receiving the pole (not shown). The clamp body 226 defines generally opposing first and second jaws 230, 232 that at least partially surround the pole-receiving slot 228. A clamp shaft 234 is movably mounted on the first jaw 230. The clamp shaft 234 has opposite ends 236, 238 and a ratchet portion 240 therebetween. The first jaw 230 has a hole 242 formed therein, and more preferably therethrough, for receiving bushing 243 and the ratchet portion 240 of the clamp shaft 234. The distal end 236 of the clamp shaft 234 extends from the first jaw 230 toward the second jaw 232. A pressure pad 244 connects, or more preferably attaches, to the distal end 236. The proximal end 238 of the clamp shaft 234 has displacement means 246. Biasing means 266 (such as a spring or other similar device) is operatively interposed between the first jaw 230 and the clamp shaft 234. A bellows element 270 encloses the clamp shaft 234 and biasing means 266. A selectively releasable positioning means or travel control means 256 is movably mounted on the first jaw 230. The travel control means 256 includes a release lever 258 that has at least one pawl 259 adapted to matingly engage the ratchet portion 240 on the clamp shaft 34 and means for biasing the pawl 259 into engagement with the ratchet portion 240. The release lever 258 and pawl 259 are shown as a unitary body; however, it will be understood that the release lever 258 and pawl 259 may be provided as separate pieces. The release lever 258 is positioned adjacent a hole 260 in the first jaw 230. The release lever 258 is pivotally mounted to the first jaw 230 by pin 261. The pawl 259 is positioned exterior to the first jaw 230 at an outer end of the hole 242, within the pole-receiving slot 228. The pawl 259 is normally biased into mating engagement with the ratchet portion 240 of the clamp shaft 234 by a biasing means 264 (such as a spring or other similar device) positioned within hole 260, and which is operatively interposed between the release lever 258 and the first jaw 230. In operation, the travel control means 256 is configured and arranged to normally resist axial movement of the clamp shaft 234 in a direction away from the pole-receiving slot 228. The travel control means 256 also permits a user to apply an axial force to the clamp shaft 234 sufficient to overcome the biasing force of the biasing means 264, to permit slide-ratcheting axial movement of the clamp shaft 234 in a direction toward the opening pole-receiving slot 228. Alternatively, in some applications it is desirable to prevent the slide-ratcheting axial movement of the clamp shaft 234 if axial force is inadvertently applied to the clamp shaft 234. In this case the biasing means 264 is selected so as to have sufficient spring force to prevent normal user force on the clamp shaft 234 from causing slide-ratcheting axial movement of the clamp shaft 234 without the user also deactivating the travel control means 256. It is therefore seen that this invention provides an improved system of interlockable portable medical devices that only allows two medical devices to be joined together. The invention also provides an improved system of interlockable portable medical devices. In addition, the invention provides an improved clamp mechanism, for mounting a medical device to a support member, which restricts the attachment of a second medical device to only one side of a first medical device when the clamp mechanism is attached to a support member. Finally, the invention provides an improved clamp mechanism that permits quick slide-ratcheting axial movement of the clamp shaft. It is therefore seen that this invention will accomplish at least all of its stated objectives. | <SOH> BACKGROUND OF THE INVENTION <EOH>The present invention generally relates to the field of medical devices, and more particularly to the field of point of care medical devices including but not limited to infusion pumps, monitors, and diagnostic equipment. The invention provides a portable point of care system that includes one or more medical devices mountable on a pole stand, bedrail or other supporting structure in close proximity to a patient. The invention includes means and methods for interlocking the medical devices together, preventing undesirable arrangements and combinations of medical devices, mounting the medical devices on the main supporting structure, and automatically providing wireless communication between the medical devices. In modern medical practice a variety of diagnostic and therapeutic devices are used, sometimes to such a degree that floor and shelf space near the patient's bedside is at a premium. One known solution to the problem of mounting medical devices is the use a pole stand. Often such pole stands have wheels for the convenience of the patient or medical personnel in moving the devices where they are needed, but wheeled pole stands can become unbalanced upon, for example, crossing thresholds or exiting elevators. Some manufacturers have mounted a central management unit and infusion pump modules in a vertically stacked configuration on a pole stand, as disclosed in U.S. Pat. Nos. 4,756,706 and 4,898,578. Vertically stacked configurations can make identification, routing and management of the associated intravenous (IV) tubes confusing and difficult. Manufacturers also have interlocked interchangeable independently functioning single channel pumps in a horizontal arrangement for attachment at a particular vertical location on a pole stand, as disclosed in U.S. Pat. No. 5,431,509. U.S. Pat. Nos. 5,713,856; 5,941,846 and 5,601,445 disclose a central control unit and a plurality of horizontally arranged detachable pump and/or sensor modules. Other manufacturers have developed multiple channel pumps, as disclosed in U.S. Pat. No. 5,378,231 and Des. 367,528. However, in the vast majority of applications a single channel pump or single pump module will suffice to meet the caregiver's needs, and customers generally are not inclined to pay the substantial premium needed to cover the manufacturing cost of a multiple channel pump or an elaborate interlocking means. Thus, there is a need for an improved system of medical devices. A primary objective of the present invention is the provision of an improved system of interlockable portable medical devices that only allows two medical devices to be joined together. Another objective of the present invention is the provision of an improved system of interlockable portable medical devices. A further objective of the present invention is the provision of an improved clamp mechanism, for mounting a medical device to a support member, which restricts the attachment of a second medical device to only one side of a first medical device when the clamp mechanism is attached to a support member. A still further objective of the present invention is the provision of an improved clamp mechanism that permits slide-ratcheting axial movement of the clamp shaft. These and other objects will be apparent to those skilled in the art. | <SOH> SUMMARY OF THE INVENTION <EOH>A first portable medical device is adapted for use in an interlocking system for interlocking the first medical device to a second medical device. The first device includes a housing having opposite sides, a selective element, a blocking element, a clamp mechanism, and wherein at least one of the opposite sides includes a first matable element to detachably interconnect a second medical device to the first medical device. The selective element restricts the attachment of the second device to only one of the opposite sides of the first device. The blocking element prevents a third medical device from attaching to either the first or second device once the first and second devices are attached. The clamp mechanism restricts the attachment of the second device to only one side of the first device when the clamp mechanism is attached to a support member. The clamp mechanism also permits slide-ratcheting axial movement of a clamp shaft. | 20040413 | 20090707 | 20050623 | 59775.0 | 1 | MENDEZ, MANUEL A | MEDICAL DEVICE SYSTEM | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,823,240 | ACCEPTED | Combination LED flashlight and garage door transmitter | A combination LED flashlight and garage door opener transmitter with at least one LED disclosed that uses a voltage multiple circuit that enables the use of a single AA or AAA battery. The voltage multiple circuit raises the battery voltage from 1.5 volts to approximately 5 volts and then maintains it to energize the LED. The voltage multiple circuit is connected to the garage door opener transmitter. | 1. A combination LED flashlight and garage door opener transmitter, comprising: a. a housing adapted to hold a battery; b. at least one battery disposed inside said housing; c. at least one LED located in said housing and used as a flashlight to illuminate a nearby surface or object; d. a voltage multiplier circuit coupled between said LED and said battery, said voltage multiplier circuit includes a synchronous boost converter that automatically adjusts and maintains the output voltage from said battery to continuously activate said LED as the internal voltage of said battery decreases; e. an ON-OFF switch electrically connected between said battery and said LED; f. a garage door opener transmitter electrically connected to said battery; and g. a garage door function switch connected to said garage door opener transmitter. 2. The flashlight as recited in claim 1, wherein said synchronous boost converter is capable of supplying 3.3 volts at 150 MA. 3. The combination LED flashlight and garage door opener transmitter as recited in claim 1, wherein said battery supplies 1.5 Volts. 4. The combination LED flashlight and garage door opener transmitter as recited in claim 1, wherein said flashlight includes two LED's. 5. The combination LED flashlight and garage door opener transmitter as recited in claim 1, further including a key ring attached to said housing. 6. The combination LED flashlight and garage door opener transmitter as recited in claim 1, further including a lens located around said LED. 7. The combination LED flashlight and garage door opener transmitter as recited in claim 6, further including a reflector located inside said lens and disposed around said LED. 8. The combination LED flashlight and garage door opener transmitter as recited in claim 1, wherein said housing is watertight. 9. A combination flashlight and garage door opener transmitter, comprising; a. a housing; b. at least one battery disposed inside said housing; c. a light electrically connected to said battery; d. a ON/OFF switch mounted on said housing and electrically connected between said battery and said light; e. a garage door opener transmitter connected to said battery; and, f. a garage door function switch. 10. The combination flashlight and garage door opener transmitter as recited in claim 9, wherein said light is an LED. 11. The combination LED flashlight and garage door opener transmitter as recited in claim 10, further including a lens located around said LED. 12. The combination LED flashlight and garage door opener transmitter as recited in claim 10, further including a reflector located inside said lens and disposed around said LED. 13. The combination flashlight and garage door opener transmitter as recited in claim 9, wherein said light is two LED's located at the end of said housing. 14. The combination LED flashlight and garage door opener transmitter as recited in claim 13, further including a lens located around said LED's. | This utility patent application is based on the provisional patent application (60/492,889) filed on Aug. 5, 2003. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to flashlights, and more particularly to flashlights that can be used to open and close garage door openers. 2. Description of the Related Art Small portable flashlights kept in a motor vehicle are relatively common. Typically they are kept in a glove box and only used in an emergency. Because the battery in the flashlight slowly discharges over time and because the flashlight is not tested regularly, the flashlight does not operate when needed. It is well known that LED bulbs are more energy efficient, have longer lives, and are more mechanically reliable than incandescent bulbs. Because of these benefits, they are commonly used in small, portable lights such as flashlights. LED flashlights found in the prior art generally consist of one or more LED bulbs located inside a housing containing a plurality of batteries. Because LEDs require 5 volts of DC current for optimal illumination, at least three AA or AAA batteries connected in a series are used. As a result, most bright LED flashlights have relatively large housings. When an LED flashlight with a smaller housing is desired, for example with an LED key ring or fob, a single battery may be used but the flashlight illumination will be substantially reduced. An LED flashlight that overcomes the above drawbacks is disclosed in a U.S. patent application Ser. No. 10/104,895) filed by the inventor on Mar. 22, 2002. Such a flashlight uses a voltage tripler and regulator that enables the use of a single AA or lithium battery. The voltage tripler is a “step-up power component” that raises the battery voltage from 1.5 volts to approximately 5 volts which, is required to sufficiently energize one or more LEDs. Garage door opener transmitters found in the motor vehicle are typically used on a daily basis. When the battery in the transmitter is discharged to a lower level, the transmitter does not operate, thus informing the user that the battery needs to be replaced. What is needed is a small portable flashlight for use in a motor vehicle that informs the user that the battery is adequately charged for operation. SUMMARY OF THE INVENTION It is an object of the present invention to provide a portable flashlight for use in a motor vehicle. It is another object of the present invention to provide such a flashlight that uses a battery that is used frequently, to inform the user that it is adequately charged for operation. It is another object of the present invention to provide such a flashlight that is combined with another electronic device frequently used in the motor vehicle which uses the same battery. These and other objects of the present invention are met by a combination flashlight and remote garage door opener transmitter. The device includes an LED light circuit, a power circuit and a voltage multiplying circuit all mounted on a printed circuit board. The LED light circuit includes at least one main LED that optimally operates at 5.0 volts. The power circuit includes at least one single AA or AAA battery mounted inside the flashlight and electrically connected to the voltage multiplying circuit that raises and maintains the battery voltage from 1.5 volts to approximately 5 volts. Connected to the voltage detector circuit is a trainable, garage door opener transmitter circuit that generates a control signal that communicates with a garage door opener receiver. The transmitter circuit is also connected to the voltage multiplying circuit to operate at 5.0 volts. During use, the working voltage of the device is maintained at 5.0 volts for operating both the LED circuit and the transmitter circuit. Since, the two circuits use the same battery, operation of one circuit informs the user of the operational status of the other circuit. DESCRIPTION OF THE DRAWINGS FIG. 1 is perspective view of the combination LED flashlight and garage door transmitter. FIG. 2 is a top plan view of the invention. FIG. 3 is a sectional, top plan view of the invention. FIG. 4 is a left side elevational view of the invention. FIG. 5 is a left side elevational view of the device showing the location of the battery, printed circuit board, and the LED. FIG. 6 is a right side elevational view of the device showing the location of the printed circuit and LED. FIG. 7 is an electrical diagram of the LED light circuit, the voltage multiplying circuit and the power circuit. FIG. 8 is a block diagram of the device. DESCRIPTION OF THE PREFERRED EMBODIMENT(S) Referring to the accompanying FIGS. 1-8, there is shown and described a combination LED flashlight and garage door opener transmitter, generally referred to as device 10. The device 10 includes an elongated hollow body 12, with a closed end 13 and a transparent main lens 28 that attaches over an open end 14. The body 12, which is made of a clear or colored plastic or similar material, is made of two half components 17, 18 that snap together along the body's central longitudinal axis 19. Formed on the closed end 13 of the body 12 is an optional key ring 20. The LED flashlight component is nearly identical to the LED flashlight disclosed in U.S. patent application Ser. No. 10/104,895, filed Mar. 22, 2002, which is now incorporated by reference herein. Attached over the open end 14 of the main body 12 is a transparent lens 28 made of plastic or similar material. The lens 28 snaps into the perimeter edges of two half components 17, 18 that form the open end 14. Formed on the outer surface of each main body 12 are two switch holes 30, 32 through which a main on/off switch button 34, garage door function button 40, 40′ extends, respectively. As shown in FIGS. 3-6, an elongated printed circuit board 42 is longitudinally aligned inside the main body 12. Aligned perpendicularly on the proximal end of the printed circuit board 42 is a smaller, multiple LED printed circuit board 43. The main printed circuit board 42 is slightly offset from the longitudinal axis 19 of the main body 12, thereby creating a longitudinally aligned cavity 50 inside the main body 12 for a single battery AAA 55. Connected to the printed circuit board 43 is a trainable, garage door opener transmitter circuit, generally denoted as 46 in FIG. 8 that generates a control signal that communicates with a garage door opener receiver 95. The circuit 46 includes an encoder circuit 47 and an antenna 48 that activates a garage door opener (not shown). FIG. 7 is a schematic of the printed circuit board 42 used in the device 10. Each printed circuit board 42 includes a LED light circuit 80, a power circuit 85, and a voltage multiplying circuit 90. The LED light circuit 80 includes at least one LED bulb 65 connected to three NPN transistors 81-83 connected in a series to a CMOS semi-conductor 84. An optional dimmer switch 98 is connected between the CMOS semi-conductor 84 and the LED bulb 65. The power circuit 85 includes a main on/off switch 96 and four NAND logic gales 86-89 that control the switch control logic and the brightness control logic. The voltage multiplying circuit 90 includes a synchronous boost converter 91 that connects to a 1.5 volt battery 55 and triples the output voltage to approximate 4.5 volts and maintains the output voltage at or near 4.5 volts. In the preferred embodiment, the synchronous boost converter 91 is a six lead thin SOT with a frequency, step-up DC/DC converted capable of supplying approximately 5.0V at 150 MA from a single 1.5 volt battery input. Such converters contain an internal NMOS switch and a PMOS synchronous rectifier that multiple and automatically adjust and maintains output voltage at a desired voltage as the input voltage drops. An example of a synchronous boost converter (Model No. LTC 3400) that may be used is sold by Linear Technology Corporation located in Milpitas, Calif. FIG. 8 is a block diagram of the device showing the relative connections of the LED the garage door transmitter circuit 46, the LED light circuit 80 and the voltage multiplying circuit 90. Table 1 lists the codes, names, and functions of the components shown in FIG. 8. In compliance with the statute, the invention described herein has been described in language more or less specific as to structural features. It should be understood, however, that the invention is not limited to the specific features shown, since the means and construction shown, is comprised only of the preferred embodiments for putting the invention into effect. The invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the amended claims, appropriately interpreted in accordance with the doctrine of equivalents. TABLE 1 Designators Qty Description C1 1 Miniature Electrolytic Capacitor C2 1 Chip Capacitor C3 1 Chip Capacitor C4 1 Chip Capacitor C5 1 Miniature Electrolytic Capacitor C6 1 Chip Capacitor C8 1 Chip Capacitor C9 1 Chip Capacitor D1 1 Schottky Barrier Rectifier D2 1 “n” LED1 1 Nichia White LED Lamp Q1 1 NPN Transistor Q2 1 NPN Transistor Q3 1 NPN Transistor R1 1 Chip Resistor R10 1 Chip Resistor R11 1 Chip Resistor R12 1 Chip Resistor R13 1 Chip Resistor R14 1 Chip Resistor R15 1 Chip Resistor R2 1 Chip Resistor R3 1 Chip Resistor R4 1 Chip Resistor R5 1 Chip Resistor R6 1 Chip Resistor R7 1 Chip Resistor R8 1 Chip Resistor R9 1 Chip Resistor PCB 1 Printed Circuit Board U1 1 Synchronous Boost Converter U2 1 CMOS Quad 2-input NAND gate | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention This invention relates to flashlights, and more particularly to flashlights that can be used to open and close garage door openers. 2. Description of the Related Art Small portable flashlights kept in a motor vehicle are relatively common. Typically they are kept in a glove box and only used in an emergency. Because the battery in the flashlight slowly discharges over time and because the flashlight is not tested regularly, the flashlight does not operate when needed. It is well known that LED bulbs are more energy efficient, have longer lives, and are more mechanically reliable than incandescent bulbs. Because of these benefits, they are commonly used in small, portable lights such as flashlights. LED flashlights found in the prior art generally consist of one or more LED bulbs located inside a housing containing a plurality of batteries. Because LEDs require 5 volts of DC current for optimal illumination, at least three AA or AAA batteries connected in a series are used. As a result, most bright LED flashlights have relatively large housings. When an LED flashlight with a smaller housing is desired, for example with an LED key ring or fob, a single battery may be used but the flashlight illumination will be substantially reduced. An LED flashlight that overcomes the above drawbacks is disclosed in a U.S. patent application Ser. No. 10/104,895) filed by the inventor on Mar. 22, 2002. Such a flashlight uses a voltage tripler and regulator that enables the use of a single AA or lithium battery. The voltage tripler is a “step-up power component” that raises the battery voltage from 1.5 volts to approximately 5 volts which, is required to sufficiently energize one or more LEDs. Garage door opener transmitters found in the motor vehicle are typically used on a daily basis. When the battery in the transmitter is discharged to a lower level, the transmitter does not operate, thus informing the user that the battery needs to be replaced. What is needed is a small portable flashlight for use in a motor vehicle that informs the user that the battery is adequately charged for operation. | <SOH> SUMMARY OF THE INVENTION <EOH>It is an object of the present invention to provide a portable flashlight for use in a motor vehicle. It is another object of the present invention to provide such a flashlight that uses a battery that is used frequently, to inform the user that it is adequately charged for operation. It is another object of the present invention to provide such a flashlight that is combined with another electronic device frequently used in the motor vehicle which uses the same battery. These and other objects of the present invention are met by a combination flashlight and remote garage door opener transmitter. The device includes an LED light circuit, a power circuit and a voltage multiplying circuit all mounted on a printed circuit board. The LED light circuit includes at least one main LED that optimally operates at 5.0 volts. The power circuit includes at least one single AA or AAA battery mounted inside the flashlight and electrically connected to the voltage multiplying circuit that raises and maintains the battery voltage from 1.5 volts to approximately 5 volts. Connected to the voltage detector circuit is a trainable, garage door opener transmitter circuit that generates a control signal that communicates with a garage door opener receiver. The transmitter circuit is also connected to the voltage multiplying circuit to operate at 5.0 volts. During use, the working voltage of the device is maintained at 5.0 volts for operating both the LED circuit and the transmitter circuit. Since, the two circuits use the same battery, operation of one circuit informs the user of the operational status of the other circuit. | 20040412 | 20061219 | 20050210 | 93588.0 | 0 | EDWARDS JR, TIMOTHY | COMBINATION LED FLASHLIGHT AND GARAGE DOOR TRANSMITTER | SMALL | 0 | ACCEPTED | 2,004 |
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10,823,341 | ACCEPTED | Image forming method | An image forming method comprises: fixing an image formed by a toner on a record sheet in a nip member formed by a pressurizing member which is compressibly contacted against a heating fixing rotor having an elastic body layer formed on an endless periphery surface capable of orbitally moving and which creates locally a large distortion occurred in the elastic body layer in vicinity of outlet thereof, wherein the toner includes at least two metal salts having different valence and has a relationship given by the Formula (1) 2.0≧a≧0.1 1.0≧b≧0.01 7.5≧a/b≧1.1 Formula (1) wherein a (mass %) is defined as a content of a metal salt which is contained at a highest content in total toner mass and b (mass %) is defined as a content of a metal salt which is contained at a second-highest content in the total toner mass, and mass values of a and b represent anhydride reduced values. | 1. An image forming method comprising: fixing an image formed by a toner on a record sheet in a nip member formed by a pressurizing member which is compressibly contacted against a heating fixing rotor having an elastic body layer formed on an endless periphery surface capable of orbitally moving and which creates locally a large distortion occurred in the elastic body layer in vicinity of outlet thereof, wherein the toner includes at least two metal salts having different valence and has a relationship given by the Formula (1). 2.0≧a≧0.1 1.0≧b≧0.01 7.5≧a/b≧1.1 Formula (1) wherein a (mass %) is defined as a content of a metal salt which is contained at a highest content in total toner mass and b (mass %) is defined as a content of a metal salt which is contained at a second-highest content in the total toner mass, and mass values of a and b represent anhydride reduced values. 2. The image forming method of claim 1, wherein a surface layer of the heating fixing rotor comprises a vulcanizate of a fluorine-containing rubber, which contains 3 to 50 parts by mass of lower molecular weight-tetra ethylene fluoride resin fine particles or polyfluoroalkylvinylether (PFA) resin fine particle per 100 parts by mass of fluorine-containing rubber. 3. The image forming method of claim 2, wherein the surface layer of the heating fixing rotor is provided with a polyfluoroalkylvinylether layer on a surface of a silicone rubber. 4. The image forming method of claim 1, further comprising: forming an electrostatic latent image on an image support member and developing the electrostatic latent image formed on the image support member, with the toner. 5. The image forming method of claim 1, further comprising: feeding the record sheet having the toner image transferred into the nip member. 6. An image forming method comprising: fixing an image formed by a toner on a record sheet in a nip member formed by a pressurizing member which is compressibly contacted against a heating fixing rotor having an elastic body layer formed on an endless periphery surface capable of orbitally moving and which creates locally a large distortion occurred in the elastic body layer in vicinity of outlet thereof, wherein the toner is one manufactured by salting out/fusing resin particles. 7. The image forming method of claim 6, wherein the toner is prepared by forming toner particles contained in the toner in a water based medium and eliminating odor. 8. The image forming method of claim 7, wherein the toner includes at least two metal salts having different valence and has a relationship given by the Formula (1): 2.0≧a≧0.1 1.0≧b≧0.01 7.5≧a/b≧1.1 Formula (1) wherein a (mass %) is defined as a content of a metal salt which is contained at a highest content in total toner mass and b (mass %) is defined as a content of a metal salt which is contained at a second-highest content in the total toner mass, and mass values of a and b represent anhydride reduced values. 9. The image forming method of claim 7, wherein a surface layer of the heating fixing rotor comprises a vulcanizate of a fluorine-containing rubber, which contains 3 to 50 parts by mass of lower molecular weight-tetra ethylene fluoride resin fine particles or polyfluoroalkylvinylether (PFA) resin fine particle per 100 parts by mass of fluorine-containing rubber. 10. The image forming method of claim 9, wherein the surface layer of the heating fixing rotor is provided with a polyfluoroalkylvinylether layer on a surface of a silicone rubber. 11. The image forming method of claim 6, further comprising: forming an electrostatic latent image on an image support member and developing the electrostatic latent image formed on the image support member, with the toner. 12. The image forming method of claim 6, further comprising: feeding the record sheet having the image into the nip member. | BACKGROUND 1. Technical Field The present invention relates to an image forming method, which is applicable to a photocopying machine, a printer, a facsimile equipment or the like, and in which an electrostatic latent image is formed on an image support member, and the formed electrostatic latent image is developed with toner, and pictorial image is formed. 2. Description of Related Art Conventionally, in the copying machine which utilizes an electrophotography process, it is necessary to fix an unfixed toner image formed on the recording sheet to form an eternity image, and a heating roller fixing method conducted by the heating and the pressurization is a general fixing method. That is, a known apparatus is a heating roller type fixing apparatus, which comprises: a heating roller which comprises a heater lamp within a cylindrical core metal and a heat resistant releasing layer formed on the outer surface thereof; and a pressure roller which is disposed in a compressibly contacting manner against this heating roller (fixing roll), and comprises a heat-resistant elastic body layer formed on outer surface of the cylindrical core metal, wherein a fixing process is conducted by applying a constant pressure between both these rollers and inserting therebetween a support member such as normal paper on which an unfixed toner image is formed. Because the heating roller type fixing apparatus used for this system has higher thermal efficiency, in comparison with other heating fixing methods such as a flash fixing system and an oven fixing system, and thus requires lower electric power, provides better processing speed, and also provides lower fire-hazardous nature caused by a paper jam, the heating roller type fixing apparatus is the most popular system at the present time. However, since the fixing apparatus of the heating roller fixing system using the heating roller (rotating part materials for fixing) requires to heat the heating roller for fixing having larger heat capacity, when transference materials and the toner are heated with the heating roller having halogen heater therein, it is disadvantageous for the energy conservation effect, and thus it provides poor energy conservation, and further, since time consumes for warming up the fixing apparatus in a printing process, there is problem of requiring longer printing time (warming up time). In recent years, there is a demand for increasing the fixing rate in such heating roller type fixing apparatus, and in order to satisfy the demand, the width of the nip region, or in other words the nip width, is required to be increased. Here, methods for increasing the nip width include a method for increasing the load exerted between these rollers, or a method for increasing roller diameter of both the fixing roller and the pressure roller, or the like. However, there is a limitation in the available fixing rate that can correspond with these methods, and in order to apply for the higher fixing rate region, a heating roller belt type fixing apparatus is developed. Pressurizing belts employed for the heating roller belt type fixing apparatus as mentioned above may mainly and be classified into two types of belts, in general. More specifically, the belts are classified into: 1) fluorine resin-coated belt, which is formed by coating the base film of endless belt shape with an adhesive referred to as “primer”, and thereafter thinly coating thereof with a fluorine resin such as polytetrafluoroethylene (PTFE) or copolymer of tetrafluoroethylene and perfluoroethylene (PFA) and so on; and 2) silicone rubber coating belt or fluorine-containing rubber coating belt, which is formed by thinly coating the base film having endless belt shape with silicone rubber or fluorine-containing rubber via a primer therebetween. As the fixing system that employs the metal belt (belt member) having the above mentioned rubber layer, and has an exothermic roller (exothermic roller member), which heats the belt member and provided in the inside of belt member, is disclosed in, for example, JP-Tokukai 2000-267356, JP-Tokukai 2000-60050 and JP-Tokukai 09-138599. However, the above-mentioned proposed fixing apparatus, which uses endless belt, has a drawback of having lower fixing strength due to its lower fixing load (pressurization) as compared with the heating roller system, and among other things, there are various problems of varying the fixing strength depending on the types of the toner and the transfer paper, and thus it is the present situation that does not reach to apply the fixing apparatus containing this system to the application of a high speed printer and a high speed photocopying machine. Furthermore, since the above-mentioned fixing system involves heating the toner image, a minor constituent included in the toner is released into the atmosphere, and there is a case, which causes an unpleasant odor for the users. More in recent years, accompanying with the reduction of the size of the photocopying machine and the printer, opportunity of using them with intimacy becomes increasingly in offices. In addition, the opportunity of using such machines in general families have been increased, and as a result, the case, in which odor emitted from the toner gives an unpleasant feeling to the user, increases more often than conventional. SUMMARY In accordance with the first aspect of the present invention, an image forming method comprises: fixing an image formed by a toner on a record sheet in a nip member formed by a pressurizing member which is compressibly contacted against a heating fixing rotor having an elastic body layer formed on an endless periphery surface capable of orbitally moving and which creates locally a large distortion occurred in the elastic body layer in vicinity of outlet thereof, wherein the toner includes at least two metal salts having different valence and has a relationship given by the Formula (1). 2.0≧a≧0.1 1.0≧b≧0.01 7.5≧a/b≧1.1 Formula (1) wherein a (mass %) is defined as a content of a metal salt which is contained at a highest content in total toner mass and b (mass %) is defined as a content of a metal salt which is contained at a second-highest content in the total toner mass, and mass values of a and b represent anhydride reduced values. In accordance with the second aspect of the present invention, an image forming method comprises: fixing an image formed by a toner on a record sheet in a nip member formed by a pressurizing member which is compressibly contacted against a heating fixing rotor having an elastic body layer formed on an endless periphery surface capable of orbitally moving and which creates locally a large distortion occurred in the elastic body layer in vicinity of outlet thereof, wherein the toner is one manufactured by salting out/fusing resin particles. By use of the first and second aspects of the present invention, a image forming method having wider range of temperature available for toner fixing, better anti-offset, longer duration life of the fixing member and reduced odor emitted in the fixing process can be provided. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not intended as a definition of the limits of the present invention, and wherein; FIG. 1 is a schematic diagram showing an example of a fixing apparatus having an endless belt that it is available to be employed in the present invention; FIG. 2 is a schematic diagram showing another example of a fixing apparatus having an endless belt that it is available to be employed in the present invention; and FIG. 3 is a sectional view diagrammatically illustrating an example of an image forming apparatus for carrying out the image forming method according to the invention. DETAIL DESCRIPTION OF EXEMPLARY EMBODIMENTS The embodiment of the present invention will be hereinafter described in details. The present inventors actively involved the investigations to address the above problems, and the results of the investigation indicate that an image forming method for heating and pressurizing a toner image on a record sheet and fixing the image on the record sheet formed by adhering a toner onto the electrostatic latent image by electrostatic potential difference in a nip member formed by a pressurizing member which is compressibly contacted against a heating fixing rotor having an elastic body layer formed on an endless periphery surface capable of orbitally moving and which creates locally a large distortion occurred in the elastic body layer of the heating fixing rotor in vicinity of outlet thereof, wherein the toner includes at least two metal salts having different valence and a (mass %) is defined as a content of a metal salt which is contained at a highest content in the total toner mass and b (mass %) is defined as a content of a metal salt which is contained at a second-highest content in the total toner mass, and the inventors finally provide higher oozing efficiency of the mold releasing agent and higher fixing rate, even if fixing load is low, and thus the present inventors achieved to complete the present invention by using the toner in which a and b satisfies a relationship given by the Formula (1), the toner manufactured by salting out/fusing resin particles, or the toner manufactured by salting out/fusing resin particles and manufactured by a step of forming particles within a water-type medium and a step of eliminating odor. The resin particle according to the present invention is set out for a resin particle produced by emulsion polymerization, mini-emulsion polymerization or the like as will be described later. The mold releasing agent may preferably be an agent contained in the resin particle, but may be toner particles formed by simultaneously salting out/fusing the resin particle and the mold releasing agent particle. Because salts are uniformly and rarely exist in the toner manufactured by salting out/fusing, the electrostatic offset is not often generated. In particular, duration life of the fixing member is considerably improved by employing the fixing apparatus having a configuration of a surface layer of a heating fixing rotor having an endless periphery surface capable of orbitally moving, in which an elastic body layer is formed on the endless periphery surface, is a vulcanizate of a fluorine-containing rubber, which contains 3 to 50 parts by mass of lower molecular weight-tetra ethylene fluoride resin fine particle or polyfluoroalkylvinylether (PFA) resin fine particle per 100 parts by mass of fluorine-containing rubber. In addition in general, the emulsion polymerization toner involves an odor problem in the fixing processing, and in particular in the fixing apparatus which uses an endless belt having an endless periphery surface capable of orbitally moving, much odor is generated, since the contact heating time or so-called fixing nip passing time is long. Therefore, it is preferable to provide with an odor elimination step for the manufacturing process of the toner used in the fixing apparatus having endless belt. The odor elimination step, which will be discussed later more specifically, employs adding a chemical deodorizer such as enzyme, plant extraction component or the like or adding of odorant/masking reagent. Details of the present invention will be described as follows. The image forming method of the present invention forms an electrostatic latent image on an image support member and adheres by a development apparatus a toner onto the electrostatic latent image formed on the image support member to form a toner image, before forms a pressurizing member by compressibly contacting it against the heating fixing rotor in which an elastic body layer is formed on an endless periphery surface capable of orbitally moving and transfers into a nip member creating locally a large distortion occurred in the elastic body layer of the heating fixing rotor in vicinity of outlet thereof a record sheet on which the toner image has been copied or a record sheet on which the toner image will be copied and fixed in the nip member. In order to achieve the above described image forming method, one of the characteristics of the present invention is to employ: a heating and fixing rotor having an endless periphery surface capable of orbitally moving as a fixing and transfer device and having an elastic body layer formed on the endless periphery surface; a pressurizing member having a nip member formed by being compressibly contacted against the heating fixing rotor, the pressurizing member creating locally a large distortion occurred in the elastic body layer in vicinity of outlet of the nip member; and transfer device for transferring into the nip member a record sheet, on which the toner image has been copied or on which the toner image will be copied and fixed in the nip member. First, the fixing apparatus according to the present invention will be described. Although examples of the fixing apparatus having the endless belt that is available to be employed in the present invention will be shown as follows, it is not intended to limit the scope of the present invention thereto. FIG. 1 is a schematic diagram showing an example of a fixing apparatus having an endless belt that it is available to be employed in the present invention. In FIG. 1, the fixing apparatus mainly comprises a heating roller 1 having a heat source therein, an endless belt 2 that is arranged to be compressibly contacted against the heating roller 1, a pressure roller 6 that stretches the endless belt 2 and two support rollers 7 and 8, and a pressure support roller 9 that pressurizes endless belt 2 against the pressure roller 6 to form a nip member. The heating roller 1 is constituted by forming an elastic body layer 4 and a releasing layer 5 in the periphery of the metal core 3, and the core 3 is composed of a cylindrical body of, for example, iron, aluminum, SUS or the like. An elastic body layer 4 is provided on the surface of the core 3. An elastic body having higher heat resistivity can be employed for the elastic body layer 4, and for example, HTV (High Temperature Vulcanization) silicone rubber having a rubber hardness 45° (JIS-A) can be formed with a desired thickness, or other material can also be used. A releasing layer 5 is provided on the elastic body layer, and for example, in addition to RTV (Room Temperature Vulcanization) silicone rubber, a fluorine-containing rubber such as Viton or a fluorine resin such as PFA (perfluoroalkoxyvinylether copolymer resin), PTFE (polytetrafluoroethylene), FEP (tetrafluoroethylene hexafluoropropylene copolymer resin) or the like can be employed to coat thereon, and for example, these releasing layer can be formed using a method such as dip-coating or a method for coating by using a tube. Further, for example, metals such as aluminum or SUS can be used for the core 3, in addition to iron. For the releasing layer 5, in addition to silicone rubber, a fluorine-containing rubber such as Viton or the like, or a fluorine resin such as PFA (perfluoroalkoxyvinylether copolymer resin), PTFE (polytetrafluoroethylene), FEP (tetrafluoroethylene hexafluoropropylene copolymer resin) or the like may be employed to coat thereon. A heating element 10 such as a halogen lamp, for example, is fixed and supported as a heat source within the core 3. In addition, a temperature sensor 11 is disposed in vicinity of the surface of the heating roller 1 to measure the surface temperature of the heating roller. In addition, based on the instrumentation signal of the temperature sensor 11, the heating element 10 is feedback-controlled by the temperature controller, which is not shown, to control the surface of the heating roller 1 to be a predetermined temperature. A releasing agent feeder is disposed in vicinity of the heating roller 1. A constant quantity of a mold releasing agent is always supplied to the surface of the heating roller 1 from the releasing agent feeder. This prevents a part of toner offset on the heating roller 1 when the unfixed toner is fixed onto the record sheet. The available mold releasing agent supplied from the releasing agent feeder may be, for example, dimethyl silicone oil (commercially available from Shin-Etsu chemical Co., Ltd. under the trade name of “KF-96”). The endless belt 2 that is a heating fixing rotor formed of the elastic body layer on the endless periphery surface is, for example, a film having desired thickness and periphery length such as, for example, a base member of polyimide film or the like, which is, for example, coated with silicone rubber to a thickness of about 30 μm as a releasing layer. The method of coating may be a method of applying a releasing layer onto the base member surface, or a method of coating a tube-shaped releasing layer material onto the base member. The endless belt 2 is stretched with a constant tensile force around the peripheries of the pressure roller 6 and the support rollers 7 and 8. The pressure roller 6 and the support rollers 7 and 8 are mainly formed of stainless steel. Among these, the pressure roller 6 is pressurized toward the center of the heating roller 1 with a desired load, and this forces the endless belt 2 compressibly contacting the heating roller 1 so that the endless belt 2 is wound up by the heating roller 1. Nip width (a die length in transportation direction of the record sheet) of this embodiment is around 20 mm, in general. One of the characteristics of the invention according to claim 3 is, as shown in FIG. 2, to have a surface layer 15 of a vulcanizate of fluorine-containing rubber composition additionally containing 3 to 50 parts by mass of lower molecular weight tetrafluoroethylene resin fine particles or polyfluoroalkylvinylether (PFA) resin particles over 100 parts by mass ofluorine-containing rubber on the endless belt surface formed on the endless periphery surface top by the elastic body layer 14, and in addition, the invention according to claim 4 is characterized in that the surface layer 15 of heating fixing rotor is provided with a polyfluoroalkylvinylether (PFA) layer formed on silicone rubber which is the elastic body layer 14. Polyfluoroalkylvinylether (PFA) may preferably be a copolymer of tetrafluoroethylene and at least one of fluoro (alkyl vinyl ether) shown by CF2═CF—O—Rf (Rf represents fluoroalkyl group of carbon number 1 to 10 in the formula), and preferably, PFA consists of 99 to 92 mass % of tetrafluoroethylene and 1 to 8 mass % of fluoro (alkyl vinyl ether). In addition, tetrafluoroethylene hexafluoropropylene copolymer (FEP) preferably consists of 96 to 87 mass % of tetrafluoroethylene and 4 to 13 mass % of hexafluoropropylene. Tetrafluoroethylene ethylene copolymer (ETFE) preferably consists of 90 to 74 mass % of tetrafluoroethylene 10 to 26 mass % and ethylene. ECTFE preferably consists of 68 to 14 mass % of ethylene and 32 to 86 mass % of chlorotrifluoroethylene. On the other hand, the pressure support roller 9 disposed in the upstream side of the transporting direction of the record sheet 12 (or also referred to as a base member) having toner 13 thereon against the pressure roller 6 is formed by, for example, coating a stainless steel core with a silicone sponge (silicone rubber foam). The pressure support roller 9 is pressurized with a constant load from the inside of the endless belt 2 toward the center direction of the heating roller 1. However, since the pressure support roller 9 is formed with a material, which is softer than the elastic body layer 4 of heating roller 1, the sponge layer of the pressure support roller 9 transforms, and almost no distortion occurs in heating roller 1. The heating roller 1 is driven to rotate at a suitable circumferential speed by the motor that is not shown, and the endless belt 2 is also driven to rotate at almost same speed by this revolution. Subsequently, the toner will be described. It is preferable that the toner includes at least two metal salts having different valence and has a relationship given by the Formula (1). 2.0≧a≧0.1 1.0≧b≧0.01 7.5≧a/b≧1.1 Formula (1) wherein a (mass %) is defined as a content of a metal salt which is contained at the highest content in the total toner mass, and b (mass %) is defined as a content of a metal salt which is contained at the second-highest content in the total toner mass, and mass values of a and b represent anhydride reduced values. The valence of the metal salt used in the present invention means a valence of a metallic element constituting thereof. An example of the measuring method of valence of the metal salt according to the present invention can be, for example, presented, in which fluorescent X-ray intensity emitted from the metal species of the metal salt (for example, calcium due from calcium chloride) is measured by using fluorescent X-ray spectrographic analysis apparatus “system 3270 type” (commercially available from Riken Kogyo Co., Ltd.) to obtain the valence of the metal salt. More specific measuring method is that: a plurality of toners having known contents of the metal salt are prepared and each 5 g of the toners is pelletized, and the relationship (calibration curve) of the contents of the metal salt (a and b) and the fluorescent X-ray intensity from the metal species contained in the metal salt (peak intensity) is measured. Subsequently, the toner (sample), which is to be measured for obtaining the contents of the metal salt therein, is similarly pelletized, and the content, or namely “quantity of metal salt in toner” can be obtained by measuring the fluorescent X-ray intensity from the metal species of metal salt of flocculant. Examples of Metal Salt The method for adding the metal salt is not particularly limited. Preferably, in the step of salting-out, cohering and fusing the resin particle from the dispersed fluid of the resin particle prepared in the water solution system, a step of employing a divalent-quadrivalent metal salts as a salting-out agent, or salting out terminator of having lower valence than the salting out agent can be employed. The means of controlling the concentration of the toner may preferably be conducted by confining the metal salt within the toner particle corresponding to the added quantity of the metal salt, the pH-value in the adding process, temperature during/after/the adding process, and thereafter removing salts from the surface by the amount of rinse water. Further, the temperature for manufacturing the toner is preferably equal to or less than 100 degree C. Having such temperature, the metal cross-linking created by the metal salts of higher valence can be selectively conducted, and thus the metal cross-link structure can be weakened at fixing temperature range of equal to or higher than 120 degree C., by metal ions of lower valence. In the toner according to the present invention, in order to effectively conduct the metal cross-linking process, the metal salt is preferably an inorganic metal salt, and the specific examples of metal salts are shown as follows. The divalent metal salt may include magnesium chloride, calcium chloride, chloride of zinc, copper sulfate, magnesium sulfate, manganese sulfate or the like, and the trivalent metal salt may include aluminum chloride, ferric chloride or the like. The quadrivalent metal salt may include titanyl sulfate, tin chloride or the like. These are appropriately selected according to the objects, and divalent or trivalent metal salt is preferable, since this provides the aggregation thereof proceeding at an appropriate speed thereby providing the control of the particle size more easily. The divalent metal salt is particularly preferable to be employed. The monovalent metal salt may include sodium chloride, potassium chloride, lithium chloride or the like. Besides the metal salt, ammonium salts such as ammonium chloride or the like can be employed. Further, compounds similar to the below-described aggregation initiator can be used as divalent or trivalent metal salt. The configurations of the preferable metal according to the present invention are shown in Table 1. TABLE 1 Higher-Valent Lower-Valent Metallic Salts Metallic Salts Particularly Divalent Metallic Salts Monovalent Metallic Salts Preferable Constitutions Preferable Trivalent Metallic Salts Divalent Metallic Salts Constitutions Other Trivalent Metallic Salts Monovalent Metallic Salts Configurations Divalent Metallic Salts Monovalent Ammonium Salts Quadrivalent Metallic Salts Trivalent Metallic Salts Quadrivalent Metallic Salts Divalent Metallic Salts Quadrivalent Metallic Salts Monovalent Metallic Salts In the toner manufactured by salting out/fusing the resin particles, it is preferable to include the later-described anionic surfactant for the water system medium that is used for associating (that is, salting out/fusing) the resin particles to grow them up. A nonionic surfactant or a cationic surfactant may be used together with an anionic surfactant, and the particle diameter can be controlled with higher accuracy by including only an anionic surfactant. Anionic surfactant may be introduced with the resin particle dispersion, or may be newly added in the association process. The toner is manufactured by salting out/fusing resin particles and manufactured by a step of forming particles within a water-type medium and a step of eliminating odor, and the details of the odor elimination technology according to the present invention will be described as follows. The odor eliminating processing by using a deodorizer is conducted in any steps from the step of forming the particles within the water-type medium to the step of separating the toner particles containing the resin and the coloring agent from the water-type medium. Although the examples of the deodorizers available for the present invention is described as follows, it is not intended to limit the scope of the present invention to these deodorizers. (Plant Extracted Component) The plant-extracted component available for the present invention is referred to as a composition, in which an extract or an extracted component derived from plants, or a composition which has a structure equivalent to that of the plant-extracted component, is dispersed in the solvent such as water or the like. In the present invention, the odor eliminating material for the plant extracted component may preferably be a compound that is capable of deodorizing the sulfur-type malodor component is preferable, and, for example, plant extract such as green tea extract, persimmon condensed tannin or bamboo extract are preferable, and these compounds have an odor eliminating effects, in which these compounds can chemically decompose hydrogen sulfide or methyl mercaptan into odorless molecules, or surrounds (wraps up) these malodor molecules to provide odorless products. When the deodorizer of the present invention containing the plant extracted components is manufactured from the green tea, crushed green leaf products of the tea leafs are immersed into ethanol, and then the ethanol extraction solution containing catechin group, vitamin group, saccharide group and enzyme group are filtered and concentrated to obtain a deodorizer containing a plant extracted component according to the present invention. More specifically, the solution is manufactured by extracting the green leafs of the tea leafs with ethanol at a temperature of equal to or less than 80 degree C., for example with ethanol of 50 to 70 degree C., and this solution contains ethanol-soluble components and water-soluble components contained in the green leafs of the tea leafs. In the extraction process of the green leafs of the tea leafs with ethanol the ethanol extracts contains the extracted component that is generally similar to the green tea extract, including flavanol group such as (−)-epicatechin (EC), (−)-epigallo catechin (EgC), (−)-epicatechin gallate (ECg), (−)-epigallo catechin gallate (EGCg) or the like, enzyme group such as oxidation-reduction enzyme, transferase, hydrolase, isomerase or the like, flavonol group such as, for example, flavone, isoflavone, flavonol, flavanone, flavaryl, orlon, anthocyanidin, chalcone, dihydrochalcone or the like, glycosides of flavonol group, caffeine, amino acid group, flavane diol group, polysaccharide group and protein group, vitamin group and so on. Since the green leaf components of the tea leafs changes by weather, atmospheric temperature, crop time and crop place, it is preferable to add the synthesized and purified vitamin C and vitamin B1 to the ethanol extract at a rate of 1 to 2 mass % of the solid contents of the ethanol extract, in order to provide stable and uniform odor elimination persistence time as the deodorizer, and to reinforce the odor elimination effect and odor elimination power of the deodorizer. Deodorizer is an alcohol solution of such as ethanol, containing catechin group, vitamin group, saccharide group, enzyme group or the like and can further contain the alcohol-extraction residues of the green leafs of the tea leafs. Accordingly, the deodorizer according to the present invention can be produced by immersing the crushed products of the green leafs of tea leafs into ethyl alcohol to extract the components of the tea leafs contained in the green leafs thereof. The other specific examples of the deodorizer containing plant-extracted component may be from the trees such as Japanese cypress, Aomori cedar, Buna, a cedar, a camphor tree, a eucalyptus or the like, or spicy grass, mustard greens, Japanese horseradish, lemon, Chinese quince, peppermint, Eugenia aromatica, cinnamomum zeylanicum, bamboo, Iriomote thistle, or Yaeyamayashi root and the extracts and extracted components can be obtained by processing these plants via crushing, compression, boiling or steam distillation. The specific examples of the extracted components of the plant origin or the synthetic compounds having equivalent chemical structure to the plant extracted components may be: tropolone group such as hinokitiol or the like, monoterpene groups such as α-pinene, β-pinene, camphor, menthol, limonene, borneol, α-terpinene, γ-terpinene, α-terpineol, terpinene-4-ol, cineol or the like, sesquiterpene group such as α-cadinol, t-murol or the like, polyphenol group such as catechin, tannin or the like, naphthalene derivatives such as 2,3,5-trimethyl naphthalene or the like, long-chain aliphatic alcohol such as citronellol or the like, aldehyde group such as cinnamaldehyde, citral, perilla aldehyde or the like, allyl compounds such as allyl isothiocyanate or the like. Further, pyracetic acid slution, which is provided by baking tree in the roaster, can be used for the present invention. When the plant-originated extracted components or the synthetic compounds having chemical structures equivalent to the plant extracted components are not water-soluble, these compounds can be employed by using a dispersant such as surfactants to be dispersed in the water. As the example of the commercially available plant extracted component deodorizer, for example, F118 (commercially available from Fine 2 Co., Ltd.) or Delsen (commercially available from Yuko Chemical Industries company) are preferably employed. In the present invention, it is preferable that at least one of the plant extracted component is phytonzid group. The phytonzid type deodorants contain the plant extract containing a phytonzid as a main component, and manufactured by adding anion activators, glycol group, special activators, host compounds into the natural polymer material having a molecular weight of 15,000 to 2,300,000 extracted from conifer trees, and the advantageous effect thereof is that odorous component is chemically decomposed completely by a neutralization inclusion method to convert thereof into other material. The commercially available phytonzid type deodorants may preferably be “Bio Dash D-200” (commercially available from DAISO). (Enzyme Type Deodorizer) In the present invention, before polymerizing the polymerization monomer in the water type solvent, and before separating the toner particles containing at least resins and coloring agents from the water type solvent, it is preferable to treat them with a deodorizer containing enzyme. In a biological oxidation enzyme, among other things, there are many compounds having the function of oxidative-degrading ammonia, amine, hydrogen sulfide, mercaptan group, indole, carbonyl compounds in a certain types of the metal content enzyme group. That is, since many of odor molecules have volatility hydrogen, the odor elimination process becomes possible by dehydrogenating and oxidizing these molecules, and creating dimer thereof, creating water-soluble compounds and creating non-vaporizing compounds. The specific examples of enzymes having odor elimination effect may be enzymes such as catalase, amylase, protease, lipase, papain, chymopapain, pepsin or the like. Catalase enzyme includes hematoporphyrin and binds to apoprotein, and contains iron in electronic state of trivalent spin, and also contains histidine glyoxaline nitrogen of protein disposed in the fifth coordination. Further, the commercially available enzyme type deodorizer may preferably be “Bio C” (commercially available from Console Corporation), and “Bio Dash P-500” (commercially available from DAISO Co., Ltd.). (Metallophthalocyanine Group and Artificial Enzyme Type Deodorizer Employing Thereof) It is preferable to employ metallophthalocyanine type deodorizers, and to manufacture the toner using the artificial enzyme type deodorizers containing metallophthalocyanine group. Metallophthalocyanine derivative having catalytic activity similar to that of catalase that is a natural enzyme, preferably carboxy phthalocyanine iron complex, and particularly preferably octacarboxy phthalocyanine iron complex, has an effect of decomposing odor molecules with a reaction kinetics similar to that of catalase. The molecular structure of octacarboxy phthalocyanine iron complex is shown as follows. [chemical formula 1] For example, when an example of oxidation mechanism of mercaptan is taken, it is shown with the following chemical reactions: 2R—SH+2OH−→2R—S−+2H2O (1) 2R—S−+2H2O+O2→R—S—S—R+H2O2+2OH− (2) (wherein, R:CH3 or C2H5): The thiolate anion, which is generated in the reaction of the upper Formula (1), becomes the active species of the ternary complex, which coordinate in metallophthalocyanine with oxygen, and subsequently as shown in the above-shown Formula (2), the thiolate anion which coordinates in this active species is deodorized by being changed into dimer. In this way, when metallophthalocyanine is employed as the deodorizer, advantageous conditions for decomposing malodor compounds are obtainable, such as: 1: reaction rate is high, and destruction efficiency is better; 2: reaction progresses by an ambient temperature; 3: since it is the water type reaction, there is no worry of the environment pollution; 4: since it is the cyclic reaction, the catalyst duration life is long, and so on. Further, the artificial enzyme, to which a metallophthalocyanine derivative and a polymer compound are bound via an ionic bonding, may be employed as a deodorizer. The specific example of the polymer compound may be cyclodextrin, which is preferably employed thereto. (Microorganism Deodorizer) Before polymerizing the polymerization monomer in the water type solvent, and before separating the toner particles containing at least resins and coloring agents from the water type solvent, it is preferable to treat them with a microorganism type deodorizer. As for the microorganism type deodorizer according to the present invention, the deodorizer employing the microorganism culture solution is used. As the microorganism, for example, microorganism at least one selected from Bacillus species, Eenterobacter species, Streptococcus species, Rhizopus species and Aspergillus species can be illustrated. Furthermore, it is preferable to employ microorganism of Nitrosomonas species, Nitrobacter species and Pseudomonas species. The microorganism deodorizer is obtainable by adding a mixture composed of 5 to 100 parts by mass of saccharide, 0.1 to 50 parts by mass of water-soluble nitride and 1,000 to 50,000 parts by mass of water to 10 parts by mass of these microorganisms, and culturing the resultant mixture under the condition of a temperature of 20 to 40 degree C., and an oxygen-feeding at a rate of 0.02 to 2.0 l/min. for 15 to 40 hours, and thereafter drying the supernatant liquid or culture medium obtained via the centrifugal separation. 20 to 300 parts by mass of a porous powder such as sawdust may be added to the culture medium as required, in order to support the microorganism thereon. Further, liquid aldehyde, more specifically glutaraldehyde may be used together with these microorganism type deodorizer. By mixing with the liquid aldehyde, the odor elimination effect considerably increases, and thus is preferable. The specific examples of the microorganism, which it is preferably employed, may be: in the microorganism of Bacillus species, in particular, Bacillus Subtilis, [IAM Culture Collection No. 1168 (IAM is an abbreviated designation of Institute of Applied Microbiology, Culture Collection Center of University of Tokyo, and hereinafter referred to as IAM)], or Bacillus Natto [IFO No. 3009, (IFO is an abbreviated designation of Institute of Institute for Fermentation Osaka, and hereinafter referred to as IFO)] are preferable, and besides, Bacillus Coagulans [IAM No. 1115] and Bacillus Macerans) [IAM No. 1243] may also be employed. As the examples of the microorganism of Eenterobacter (Enterobacter) species, Eenterobacter Sakazaki [IAM No. 12660], Eenterobacter Agglonerans [IAM NO. 12659] or the like can be employed. As the examples of the microorganism of Streptococcus species, Streptococcus Faecalis [IAM No. 1119], Streptococcus Cremoris [IAM NO. 1150], Streptococcus Lactis [IFO No. 12546] or the like can be employed. As the examples of the microorganism (fungus) of Rhizopus species, Rhizopus Formosaensis [IAM No. 6250], Rhizopus Oryzae [IAM No. 6006] or the like can be employed. As the examples of the microorganism of Aspergillus species, Aspergillus Oryzae [IFO No. 4176], Aspergillus Niger [IF04066] or the like can be employed. As the examples of the microorganism of Nitrosomonas species, Nitrosomonas Europaea [IFO No. 14298] or the like can be employed. As the examples of the microorganism of Nitrobacter species, Nitrobacter Agilis [IFO No. 14297] or the like can be employed. As the examples of the Pseudomonas species, Pseudomonas Caryophilli [IFO No. 12950], Pseudomonas Statzeri [IFO No. 3773] or the like can be employed. The microorganism deodorizer according to the present invention may includes microorganisms in dormancy, the organic acids which are effective for the odor elimination, and enzyme for decomposing the organic substances. That is, the effects are achieved, in which the microorganisms can convert saccharide and ethyl alcohol into organic acid such as lactic acid, citric acid, malic acid or the like, or the enzyme (amylase, protease, lipase) is produced to decompose the malodor sources (organic substances). (Plant Oil Deodorizer: 1) The materials, which are effective for the present invention, are plant essential oils provided from the plants of Lauraceae, Apiaceae, Myrtaceous, Labiate, Pinaceae, Cupressaceae and Gramineae. More specifically, the following plant essential oil can be illustrated. For example, the expression of “cinnamon oil” appeared in the following descriptions indicates that the “cinnamon oil” is an essential oil extracted from cinnamon with a steam distillation technique. Further, main constitution chemical compound nomenclature in the essential oil components are indicated in the parentheses. These plant essential oils may be used alone or mixed thereof. Further, it is self-evident using a main constitution chemical compound itself. As Lauraceae, for example, cinnamon oil (cinnamaldehyde, cinnamaldehyde), camphor oil (linalool), ravensara oil (1,8-cineol, α-terpineol), ravensara eugenol oil (1,8-cineol, eugenol), rosewood oil (linalool, α-terpineol), laurier oil (linalool, 1,8-cineol, eugenol) or the like; as Apiaceae, for example, caraway oil (d-carvone, limonene), anise oil (anethole, anisaldehyde), anjelica oil (α-pinene, α-phellandrene), galbanum oil (pinene, γ-cadinol), carrot seed oil (carotol), cumin oil (cuminal), coriander oil (linalool, decanal, decenal, octanal), dill oil (epoxy menthane, phellandrene, carvone), fennel oil (anethole, fenchone), lovage oil (butylidene phthalide, β-phellandrene, terpinyl acetate, ocimene) or the like; as Myrtaceous, for example, eugenia aromatica oil (eugenol acetate, eugenol), cajeput tree oil (1,8-cineol, α-terpineol), tee tree oil (terpinenol-4, γ-terpinene), niaouli oil (1,8-cineol, viridiflorol), niaouli nerolidol oil (nerolidol), myrtle (myrtle or myrtus communis) oil (1,8-cineol, α-pinene, geranyl acetate), eucalyptus globulus oil (globulol, pinocarvone, 1,8-cineol), eucalyptus staigeriana (eucalyptus lemon) oil (citral, geranyl acetate), eucalyptus smithii (α-terpineol, 1,8-cineol), eucalyptus dives oil (piperitone, phellandrene), eucalyptus radiata oil (α-terpineol, 1,8-cineol), eucalyptus citriodora oil (citronellal, citronellol) or the like; as Labiate, for example, sage oil (thujone, camphor), patchouli oil (patchouli alcohol, guaiene), lavender (high-R lavender) oil (linalyl acetate, linalool), rosemary camphor oil (camphor, 1,8-cineol), rosemary cineol oil (1,8-cineol), spearmint oil (1-carvone, limonene), thyme geraniol oil (geraniol, geranyl acetate), thyme thymol oil (thymol, p-cymene), thyme thujanol oil (thujanol-4, terpinenol-4), thyme linalool oil (linalool, linalyl acetate), thyme satureioides oil (borneol, α-terpineol, carvacrol), ocimum basilicum oil (methyl chavicol) or the like; as Pinaceae, for example, cedarwood oil (cadinene, atlantone), pine oil (α-pinene, β-pinene, β-caryophyllene, α-terpineol), pinus sylvestris oil (α-pinene, β-pinene), abies sibirica oil (bornyl acetate, camphene), abies balsamea oil (β-pinene, bornyl acetate) or the like; as Cupressaceae, for example, cupressus sempervirens oil α-pinene, β-pinene, terpinyl acetate, cedrol), Juniper branch oil (α-pinene, β-pinene, thujopsene, sabinene), juniper berry oil (α-pinene, terpinenol-4, germacrone) or the like; and further, as Gramineae, for example, citronella oil (methyl isoeugenol, geraniol), palmarosa oil (geraniol, geranyl acetate), vetiver oil (vetiverone), lemongrass oil (geranial, neral, geraniol) or the like, can be illustrated. (Plant Oil Deodorizer: 2) The materials, which are effective for the present invention, is characterized in that the materials contains at least one selected from the group consisting of eugenol, cinnamaldehyde, p-cymene, benzaldehyde, benzyl acetate and benzyl benzoate. Eugenol includes, for example, ravensara eugenol (Lauraceae), ocimum basilicum eugenol (Labiate), and eugenia aromatica (Myrtaceous); cinnamaldehyde includes cinnamon (Lauraceae); p-cymene includes thyme thymol (Labiate); and benzyl benzoate includes ylang ylang (van Litchi chinensis). In addition to above, the plant oil manufacture means aromatic and volatility oils, which are obtainable from flowers, leafs, fruits, branches, roots or the like of various kinds of plants. (Amyris Oil Type Deodorizer) Amyris oil is a plant essential oil extracted from xylems and seeds of (Amyris Balsamifera, which is a Rutaceae vegetated in the northern part of the North America, with a steam distillation. The main constituents are cadinol, cadinene and caryophyllene. Method of the application is to use a surfactant to emulsify the amyris oil in the water. This emulsion is used as a cleaning solution in the filtration and washing process after conducting the reaction of polymerization or salting out/fusing. As a result, this reacts with a chain transfer agent remaining on the surface of the coloring particle, and thus decomposing the odorous component and eliminating the odor by the chemical reaction. (Macrocyclic Lactone and Macrocyclic Ketone Compounds) The macrocyclic lactone compounds used as flavor may be, for example, 14-tetradecanolide, 15-pentadecanolide, 11(orl2)-pentadecene-15-olide, 16-hexadecanolide and 9-hexadecene-16-olide. Further, as macrocyclic ketone compounds used as flavor, for example, cyclopentadecanone, 3-methyl-cyclopentadecanone, cyclohexadecanone, 5-cyclohexadecene-1-one, 8-cyclohexadecene-1-one, cycloheptadecanone, 3-ethyl-cyclopentadecanone, 3-propyl-cyclopentadecanone, 9-cycloheptadecene-1-one, cycloheneicosanone, 3-methyl-cycloheneicosanone, and 11-cycloheneicosen-1-one can be illustrated. (Pyruvic Ester Group) It is found that highly effective odor elimination effects with higher safety can be obtained by employing a pyruvic ester group shown below. [Chemical Formula 2] Here, R represents linear, branched or cyclic alkyl group, alkenyl group, aryl group and aralkyl group having 1 to 18 carbons. More specifically, alkyl group may includes groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, amyl group, isoamyl group, hexyl group, heptyl group, octyl group, nonyl group, 2-ethylhexyl group, decyl group, cyclopentyl group, cyclohexyl group or the like; and aryl group may includes phenyl group, or substituted phenyl group such as tolyl group, p-chlorophenyl group or the like. Further, aralkyl group may include benzyl group, phenethyl group, phenylpropyl group, methylbenzyl group, dimethylbenzyl group, trimethyl benzyl group, P-isopropyl benzyl group. Aralkyl group may include norbornyl group, citronellyl group, geranyl group or the like. On application of these chemical compounds, these compounds can be empolyed alone or mixed thereto. Preparation of pyruvic acid can be carried out by conducting an esterification of pyruvic acid via a commonly known method, or by conducting a method for oxidizing lactic acid ester or the like. In the method of the application, a surfactant is first used to emulsify the pyruvic esters in the water. Subsequently, it is preferable to clean thereof by adding pyruvic esters to a cleaning solution for the toner particles so that the ratio of pyruvic esters is 0.001 to 1 mass % level over the whole coloring particles at the time of the cleaning process. Concerning this cleaning step, since the effect of the cleaning increases by repeating the step, the cleaning step may be repeated. (Deodorizer Dissolved or Dispersed in Water) Before polymerizing the polymerization monomer in the water type solvent, and before separating the toner particles containing at least resins and coloring agents from the water type solvent, it is preferable to treat them with a deodorizer dissolved or dispersed in the water, and more specifically, among the toner manufacturing process comprising the polymerization step, the salting out/fusing step, the solid-liquid separation step, the drying step and the externally adding step, it is particularly preferable to process an odor elimination in any step from the polymerization step to the solid-liquid separation step. The deodorizer solution may contain the water in a ratio of equal to or higher than 50 mass %, and may further contain alcohols, alcoholamines, surfactants and organic acids such as citric acid or the like. (Adsorption of Deodorizer to Toner Particle Surface) Even if the toner odorous components ooze from toner interior, in the drying step or after the step of sealing the package, it is preferable that deodorizer takes the condition, which adsorbed on the surface, in view of maintaining the odor elimination function. Although the method for adsorbing thereof may not be particularly limited, it is desirable to dissolve or disperse the water type medium for polymerize, salt out and flocculate the toner, after removing the residual deposits of surfactant and salting out agent in the toner filtration cleaning process discussed later, it is particularly preferable to treat with the deodorizer liquid of high concentration. It is preferable that the concentration of the deodorizer for adsorbing may be 0.01 to 10 ppm over the toner. The concentration of equal to or less than 0.01 ppm provides lower durability for the odor elimination function, and the concentration of equal to or higher than 10 ppm provides unstable charging characteristics. Further, the polymerization method toner comprising the resin and the colorant which are formed by polymerizing the radical polymerization monomer containing the above-mentioned respective chain transfer agents in the water type medium, it is preferable that radical polymerization monomer is contained in the polymerization method toner in the concentration of equal to or less than 200 ppm and the chain transfer agent is contained in the concentration of equal to or less than 50 ppm. In order to achieve this, in the method for manufacturing the polymerization method toner by fusing the resin particle which is formed by polymerizing the radical polymerization monomer including the chain transfer agent in the water type medium with at least using the water soluble polymerization initiator in the water type medium, it is preferable to conduct the manufacturing method by adding the water-soluble polymerization initiator for a plurality of cycles. Further, in the polymerization method toner, it is preferable to use the chain transfer agent itself emitting lower odor, and the chain transfer agent available in the present invention will be listed below, though it is not intended to limit the scope of the present invention thereto. An example of the chain transfer agent may be chemical compound shown in the following general formula (1) or general formula (2). HS—R1—COOR2 General formula (1) (wherein, in the general formula, R1 is hydrocarbon group having 1 to 10 carbons and may have substituent group, R2 is hydrocarbon group having 2 to 20 carbons and may have substituent group,) The preferable chemical compounds of the above-mentioned general formula (1) may be thioglycollic acid ester or 3-mercaptopropionic acid ester. More specifically, thioglycollic acid ester includes ethyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, isooctyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate, thioglycollic acid ester of ethylene glycol, thioglycollic acid ester of neopentyl glycol, thioglycollic acid ester of trimethylolpropane, thioglycollic acid ester of pentaerythritol and thioglycollic acid ester of sorbitol; and 3-mercaptopropionate ester includes ethyl ester, octyl ester, decyl ester, dodecyl ester, pentaerythritol tetrakis ester, 3-mercaptopropionate ester of ethylene glycol, 3-mercaptopropionate ester of neopentyl glycol, 3-mercaptopropionate ester of trimethylolpropane, 3-mercaptopropionate ester of pentaerythritol and 3-mercaptopropionate ester of sorbitol. HS—R3 General formula (2) (wherein, in the general formula, R3 is hydrocarbon group having 1 to 20 carbons and may have substituent group.) The preferable compounds may include n-octyl mercaptan, 2-ethylhexyl mercaptan, n-dodecyl mercaptan, sec-dodecyl mercaptan and t-dodecyl mercaptan. Further, other preferable chain transfer agent may be terpen type compound. Terpen type compounds includes the compound having performances same as mercaptan type compound for the chain transfer agent, and having the performance that does not emit any odor in the fixing process by heating. That is, in the toner, in terpen type compound, it is preferable to employ the toner which utilizes the resin fine particles produced via the polymerization method using monoterpene or sesquiterpene type compounds as the chain transfer agent. Furthermore, the particularly preferable chemical compound in monoterpene type compounds may include α-pinene, β-pinene, 3-carene, camphene, limonene, terpinolene, α-terpinene, myrcene, α-terpineol, β-terpineol, linalool, nerol, and Geraniol, and particularly preferable compounds in sesquiterpene type chemical compounds may include longifolene and caryophyllene. The monoterpene type compound chain transfer agents and sesquiterpene type compound chain transfer agents may be employed in a manner same as that employed for chain transfer agents such as conventionally known thioglycerine, thioglycollic acid, thioglycollic acid ester, mercaptan type compound, tetrachloromethane, chloroform or the like. The amount of monoterpene type compound or sesquiterpene type compound may preferably be 0.01 to 5 mass % for the amount of the radical polymerization monomer composition and more preferably 0.05 to 4 mass The rate of equal to or less than 0.01 mass % provides insufficient effect thereof, and the rate exceeding 5 mass % provides remaining the chain transfer agent with the condition of not reacting and is not preferable. Further, as other preferable chain transfer agent, mercapto silane type chain transfer agent can be used. As mercapto silane type chain transfer agents available for the present invention may includes, for example, mercaptomethyl dimethoxy silane, mercaptomethyl diethoxy silane, mercaptomethyl ethyl dimethoxy silane, mercaptomethyl ethyl diethoxy silane, 2-mercaptoethyl dimethoxy silane, 2-mercaptoethyl diethoxy silane, 2-mercaptoethyl ethyl dimethoxy silane, 2-mercaptoethyl ethyl diethoxy silane, 3-mercapto propyl methyl dimethoxy silane, 3-mercapto propyl methyl diethoxy silane, 3-mercapto propyl ethyl dimethoxy silane, 3-mercapto propyl ethyl diethoxy silane, 4-mercapto butyl methyl dimethoxy silane, 4-mercapto butyl methyl diethoxy silane, 4-mercapto butyl ethyl dimethoxy silane, 4-mercapto butyl ethyl diethoxy silane, 8-mercapto octyl ethyl dimethoxy silane, 8-mercapto octyl ethyl diethoxy silane, 12-mercapto dodecyl ethyl dimethoxy silane, 12-mercapto dodecyl ethyl diethoxy silane or the like. The preferable amount of use of the above chemical compounds may be 0.01 to 5 mass % over the whole toner mass. Further, known water-soluble chain transfer agents can be employed for the other chain transfer agents, and the examples thereof may include, for example, sodium sulfite, sodium bisulphite, bisulfite potassium, sodium pyrosulfite, potassium pyrosulfite, chloromethanol, 2-chloroethanol, 1-chloro-2-propanol, 2-chloro-n-propanol, 3-chloro-n-propanol, 2-chloro-n-butanol, 3-chloro-n-butanol, 4-chloro-n-butanol, chloropentanol, chlorohexanol, chloroheptanol, chlorooctanol, monochloroacetate, dichloroacetic acid, trichloroacetic acid, chloro difluoro acetic acid, α-chloropropionate, β-chloropropionate, p-chlorobenzoic acid, 2-chloro-6-fluorobenzoate, α-bromopropionic acid, β-bromopropionic acid, 2-bromo-n-valeric acid, 5-bromovaleric acid, 11-undecanoic acid, α-bromophenylacetic acid, p-bromophenylacetic acid, 2-bromooctane acid, 2-bromopentane acid, 2-bromohexanoic acid, 6-bromohexanoic acid, chlorosuccinic acid, chlorofumaric acid, chloromaleic acid, chloromalonic acid or the like. Next, the method for manufacturing toner will be described. (Method for Manufacturing Toner) One of the characteristics of the method for manufacturing the toner according to the present invention is that the polymerization process for the polymerization monomer is carried out within the water type medium. That is the method, in which, when the resin particle (nuclear particle) containing mold releasing agent or coating layer (interlayer) is formed, the mold releasing agent is dissolved in the monomer, and the obtained monomer solution is drop-dispersed in the water type medium, and further the polymerization initiator is added in this medium to conduct the polymerization process, thereby obtaining the products as latex particles. The water type medium as set forth in the present invention means the medium containing 50 to 100 mass % of water and 0 to 50 mass % of the water-soluble organic solvent. As water-soluble organic solvent, for example, methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, tetrahydrofuran or the like can be exemplified, and it is preferable to employ the alcohol type organic solvent which does not dissolve the obtained resin. One example of the method for manufacturing the toner will be described as follows. The manufacturing process of the toner is mainly constituted of the processing steps shown below. 1: A multistage polymerization step (I) for obtaining the composite resin particles, in which mold releasing agent and/or crystalline polyester is contained in the region (core or midlayer) except the external layer thereof; 2: A salting out/fusing step (II) for salting out/fusing the composite resin particles and the colorant particles to obtain the toner particles; 3: A filtering/cleaning step for filtering the toner particles from the distributing liquid system for the toner particles to remove the surfactant from the toner particle; 4: A drying step for drying the toner particles which has been cleaned; and 5: A step for adding the external addition agent to the toner particles, which has been dried. Each of the step will be described in detail as follows. [Multistage Polymerization Step (I)] A multistage polymerization step (I) is the step, in which the composite resin particles are manufactured by forming the coating layer that comprises polymer of the monomer on surface of resin particles formed by the multistage polymerization method. It is preferable to adopt the multistage polymerization method of equal to or more than three-step polymerization, in view of maintaining the stability of the manufacturing process and improving the breaking strength of the obtained toner. The two-step polymerization method and three-step polymerization method, which are a representative example of the multistage polymerization method, will be described as follows. (Two-Step Polymerization Method) The two-step polymerization method is a method for manufacturing the composite resin particles composed of the core (nucleus) formed of the high molecular weight resin containing the mold releasing agent and an outer layer (shell) formed of low molecular weight resin. That is, the composite resin particles obtained via two-step polymerization method consists of nucleus and one level of the coating layer. Describing the method more specifically, first of all, the mold releasing agent is dissolved in monomer L to prepare the monomer solution, and after drop-dispersing this monomer solution in the water type medium (for example, aqueous solution of a surfactant), the polymerization processing (the first step polymerization) of this system is carried out to prepare the dispersion liquid of the resin particles of high molecular weight including the mold releasing agent. Subsequently, the polymerization initiator and monomer L for obtaining the low molecular weight resin are added to the dispersion liquid of the resin particles, and the polymerization processes for monomer L under the presence of the resin particles is carried out (the second step polymerization) to form the coating layer, which consists of resin of low molecular weight (polymer of monomer L), on the surface of the resin particles, and thus the method is completed. (Three-Step Polymerization Method) The three-step polymerization method is a method for manufacturing the composite resin particles composed of the core (nucleus) formed of high molecular weight resin, the interlayer containing the mold releasing agent and the outer layer (shell) formed of low molecular weight resin. That is, the composite resin particles obtained via the three-step polymerization method are composed of the nucleus and coating layers of the dual layers. Describing the method more specifically, first of all, the dispersion liquid of the resin particles obtained by the polymerization processing which is carried out according to the usual method (the first plate polymerization) is added into the water type medium (for example, aqueous solution of a surfactant), and after drop-dispersing the monomer solution, which contains the mold releasing agent dissolved in monomer M, into above-described water type medium, the polymerization processing (the second step polymerization) of this system is carried out to form the coating layer (interlayer) consisting of the resin (polymer of monomer M) containing the mold releasing agent on the surface of resin particles (nuclear particle), thereby preparing the dispersion liquid of the composite resin particle (high molecular weight resin—medium molecular weight resin). Subsequently, polymerization initiator and monomer L for obtaining low molecular weight resin are added into the dispersion liquid of the obtained composite resin particles, and the polymerization processes for monomer L under the presence of the composite resin particles is carried out (the third step polymerization) to form the coating layer, which consists of resin of low molecular weight (polymer of monomer L), on the surface of the composite resin particles. In the above method, the mold releasing agent can be finely and uniformly dispersed by incorporating the second plate polymerization step in the manufacturing process, and thus is preferable. The polymerization method, which is preferable for forming the resin particles or the coating layer containing the mold releasing agent, may include the method for conducting the radical polymerization in the oil drops by dispersing the monomer solution, which includes monomer with mold releasing agent dissolved therein in the water type medium, in which a surfactant having a concentration equal to or less than the critical micelle concentration by utilizing a mechanical energy to prepare the dispersion liquid, and adding the water soluble polymerization initiator into the obtained dispersion liquid (hereinafter called “mini-emulsion technique” in the present invention), and the method can fully provide the advantageous effect of the present invention, and thus is preferable. Here, in the above method, oil soluble polymerization initiator may be replaced with water-soluble polymerization initiator, or employed with the water-soluble polymerization initiator. According to the mini-emulsion technique automatically forming oil drops, unlike the usual emulsion polymerization method, enough amount of the mold releasing agent can be introduced in the formed resin particles or in the coating layer without eliminating the mold releasing agent, which is dissolved in the oil phase. Here, the disperser for conducting the oil drop dispersion by the mechanical energy is not particularly limited, and may includes, for example, stirring apparatus “CLEARMIX”, that comprises a rotor capable of rotating at higher speed (commercially available from M-Technique Co., Ltd.), an ultrasonic dispersion machine, a machine homogenizer, a Manton Gaulin homogenizer, a compression homogenizers or the like. Further, the dispersed particle diameter may be 10 to 1,000 nm, and preferably 50 to 1,000 nm and more preferably 30 to 300 nm. In addition to above, as the other polymerization method for forming the resin particles containing the mold releasing agent or forming the coating layer, known methods such as emulsion polymerization method, suspension polymerization method, seed polymerization method or the like can be adopted. Further, these polymerization methods may also be adopted to obtain the resin particles (nuclear particle) constituting the composite resin particles or the coating layer, which are free of the mold releasing agent and the crystalline polyester. The particle diameter of the composite resin particles obtained from the polymerization step (I) may preferably be in a range of 10 to 1,000 nm as the mass mean particle diameter measured using the electrophoretic light scattering photometer “ELS-800” (commercially available from Otsuka Electronic Co., Ltd.). Further, it is preferable that the glass transition temperature (Tg) of the composite resin particles is in the range of 48 to 74 degree C., and it is more preferably 52 to 64 degree C. Further, it is preferable that the softening point of the composite resin particle is in the range of 95 to 140 degree C. [Salting Out/Fusing Step (II)] The salting out/fusing step (II) is a step for obtaining the toner particle of indefinite form (non-spherical form) by salting out/fusing the composite resin particles obtained via the aforementioned multistage polymerization step (I) and the colorant particles (proceeding the salting out process and the fusing process simultaneously). The term “salting out” used in the present invention means flocculating the composite resin particles, which are in the condition of being dispersed in the aqueous medium by utilizing the function of salt. Further, the term “fusing” means disappearing the interface between particles of the resin particles, which are flocculated by the above salting-out. The term “salting out/fusing” used in the present invention means two steps of salting out and fusing are taken place in sequence, or causing these steps in sequence. In order to causing the salting out step and the fusing simultaneously, it is necessary to flocculate the particle (composite resin particles, colorant particles) at the temperature condition of equal to or higher than the glass transition temperature (Tg) of the resin constituting the composite resin particles. In this salting out/fusing step (II), the internal addition agent particles such as charging control agent or the like (fine particles having a number average primary particle diameter of about 10 to 1000 nm level) may be salting out/fused together with the composite resin particles and the colorant particles. Further, the colorant particles may be surface-reformed, and a known conventional surface reforming agent may be employed. Salting out/fusing processing of the colorant particles is carried out with a condition of being dispersed in the aqueous medium. As the aqueous medium containing the dispersed colorant particles, aqueous solution, in which a surfactant is dissolved with a concentration of equal to or higher than the critical micelle concentration (CMC), is preferable. The disperser using for dispersing processing of the colorant particles is not particularly limited, and may preferably includes a stirring apparatus “CLEARMIX”, that comprises a rotor capable of rotating at higher speed (commercially available from M-Technique Co., Ltd.), an ultrasonic dispersion machine, a machine homogenizer, a Manton Gaulin homogenizers, a pressurizing disperser such as a compression homogenizer, a Getzmann mill, a medium type disperser such as a diamond fine mill or the like. In order to salting out/fusing the composite resin particles and the colorant particles, it is necessary to add the salting out agent (flocculent) having a concentration of equal to or higher than the critical aggregation concentration into the dispersion liquid, in which the composite resin particles and the colorant particles are dispersed, while heating this dispersion liquid to a temperature equal to or higher than the glass transition temperature (Tg) of the composite resin particles. The preferable temperature range for salting out/fusing may be within a range of from (Tg+10 degree C.) to (Tg+50 degree C.), and more preferably within a range of from (Tg+15 degree C.) to (Tg+40 degree C.). Further, in order to conduct the fusing process effectively, an organic solvent capable of infinitely dissolving in water may be added. [Filtration and Cleaning Processes] In this filtration/cleaning processes, the filtration process for filtering the toner particles from the dispersion system of the toner particles obtained in the step mentioned above, and the cleaning process for removing the residual deposits of surfactant and/or salting out agent from the filtered toner particles (cake-like flocculates) are conducted. Here, the filtration processing methods may include the centrifugal separation method, the filtration under diminished pressure method utilizing a nutsche filter, a filtration method utilizing a filter press or the like, and not particularly limited thereto. [Drying Step] This drying step is a process step, in which the drying processing is carried out for the toner particles that have been clean-processed. The drying machine used in this step may include a spray dryer, a vacuum freeze dryer, a reduced pressure drying machine or the like, and preferable drying machine for the use in the present invention may be a standing type shelf drying machine, a portable type shelf drying machine, a fluidized bed drying machine, a rotary drying machine, a stirrer type drying machine or the like. The moisture of the toner particles, which have been dry processed, may preferably be equal to or less than 5 mass %, and more preferably equal to or less than 2 mass %. In addition to above, when the dry processed toner particles are flocculated with weak attractive forces therebetween, the flocculates may be crushing-processed. In this place, the crushing processing unit may include mechanical crushing machines such as a jet mill, a henschel mixer, a coffee mill, a food processor or the like. The toner according to the present invention may preferably be prepared by forming the composite resin particles under the condition of free of any colorant, adding the dispersion liquid of the colorant particles into the dispersion liquid of the composite resin particles, and salting out/fusing the composite resin particles and the colorant particles. As such, the polymerization reaction for obtaining the composite resin particles is not obstructed by conducting the preparation of the composite resin particles in the system, in which any colorant does not exist. Thus, according to the toner of the present invention, contamination of the fixing apparatus by the accumulation of the toner and the image stain are not generated without deteriorating the superior offset resistance. Further, as a result that the polymerization reaction for obtaining the composite resin particles is ensured to be conducted, monomer and oligomer do not remain in the obtained toner particles, and bad odor is not generated in the thermal fixing step in the process for forming the image utilizing this toner. Further, the surface characteristics of the obtained toner particle are homogeneous, and the distribution of the quantity of charging also becomes sharp, thus the image, which is superior in the sharpness, can be formed for longer term. By employing the toner, in which the composition, the molecular weight and the surface characteristics are uniform between the toner particles, improvements in the offset resistance and in the characteristics for preventing the winding up can be achieved, while maintaining better adhesive property (high fixing strength) for the image support in the image formation process including the fixing step by the contact heating manner, and thus the image having moderate glossiness can be obtained. Next, respective configuration factor used in the toner manufacturing process will be described in detail. (Polymerization Monomer) Polymerization monomer for producing the resin (binder) used for the present invention contains hydrophobic monomer as an essential configuration component thereof, and cross-linking monomer is additionally employed as required. Further, as described below, it is desirable to contain at least one of monomer having acid polar group or monomer having basic polar group. (1) Hydrophobic Monomer Hydrophobic monomer constituting monomer component is not particularly limited, and conventionally known monomer can be employed. Further, one, two or more monomers may be combined to be used so that the required properties are satisfied. More specifically, mono vinyl aromatic type monomers, (meta) acrylate type monomers, vinylester type monomers, vinyl ether type monomers, monoolefin type monomers, diolefin type monomers, halogenation olefinic type monomers can be employed. Vinyl aromatic type monomer, for example, may include styrene type monomers and derivatives such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenyl styrene, p-chlorostyrene, p-ethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, 2,4-dimethylstyrene, 3,4-dichloro styrene or the like. Acrylic type monomer may include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, β-hydroxy ethylacrylate, γ-amino propylacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate or the like. Vinylester type monomer may include vinyl acetate, vinyl propionate, vinyl benzoate or the like. Vinyl ether type monomer may include vinyl methyl ether, vinyl ethyl ether, Vinyl isobutyl ether, vinyl phenyl ether or the like. Monoolefin type monomer may include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene or the like. Diolefin type monomer may include butadiene, isoprene, chloroprene or the like. (2) Cross-Linking Monomer Cross-linking monomer may be added in order to improve the characteristics of the cross-linking monomer resin particles. Cross-linking monomer may include monomer having two or more unsaturated bonds, such as for example, divinylbenzene, divinyl naphthalene, divinyl ether, diethyleneglycol methacrylate, ethylene glycol dimethacrylate, polyethyleneglycol dimethacrylate, diallyl phthalate or the like. (3) Monomer Having Acidity Polar Group Monomer having acidity polar group having acid polar group may include: (a) α,β-ethyleny unsaturated compound having carboxyl group (—COOH) and (b) α,β-ethyleny unsaturated compound having sulfone group (—SO3H). Examples of α,β-ethyleny unsaturated compound having —COO group of the above (a) may be acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, maleic acid mono octyl ester, salts of these compounds with metal such as Na, Zn or the like. Examples of α,β-ethyleny unsaturated compound having —SO3H group of the above (b) may be styrene sulfonate and Na salt thereof, allylsulfosuccinic acid, octylallyl sulfosuccinate and Na salt thereof, or the like. (4) Monomer Having Basic Polar Group Monomer having basic polar group having basic polar group may be (i) (meta) acrylic acid ester of aliphatic alcohol having amine group or quaternary ammonium group and having 1 to 12 carbons, preferably 2 to 8 carbons and particularly preferably 2 carbons, (ii) (meta) acrylic acid amide or substituted (meta) acrylic acid amide mono-substituted or di-substituted with alkyl group having 1-18 carbons on N, (iii) vinyl compound substituted with heterocyclic group having N as members of ring, and (iv) N, N-diallyl-alkylamine or quaternary ammonium salt thereof. Among these, (1) (meta) acrylic acid ester of aliphatic alcohol having amine group or quaternary ammonium group is preferable as monomer having basic polar group. Examples of (i) (meta) acrylic acid ester of aliphatic alcohol having amine group or quaternary ammonium group may be dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, quaternary ammonium salts of above-listed four compounds, 3-dimethylaminophenyl acrylate, 2-hydroxγ-3-methacryloxy propyl trimethylammonium salt or the like. (ii) (meta) acrylic acid amide or substituted (meta) acrylic acid amide mono-substituted or di-substituted with alkyl group having 1 to 18 carbons on N may be acrylamide, N-butylacrylamide, N,N-dibutyl acrylamide, piperidyl acrylamide, methacryl amide, N-butyl methacryl amide, N,N-dimethylacrylamide, N-octadecyl acrylamide or the like. (iii) vinyl compound substituted with heterocyclic group having N as members of ring may include vinylpyridine, vinylpyrrolidone, vinyl-N-methylpyridinium chloride, vinyl-N-ethylpyridinium chloride or the like. Examples of (iv) N,N-diallyl-alkylamine may be N,N-diallylmethylammonium chloride, N,N-diallyl ethylammonium or the like. (polymerization Initiator) Radical polymerization initiator is appropriately available for the use in the present invention as long as being water soluble. For example, persulfates (for example, potassium persulfate, ammonium persulfate or the like), azo compounds (for example. 4,4′-azobis 4-cyanovaleric acid and salts thereof, 2,2′-azobis(2-amidinopropane) salt or the like), peroxide compounds or the like. Furthermore, above-mentioned radical polymerization initiator can be combined with reducing agent as required to create a redox type initiator. By employing redox type initiator, the polymerization activity increases, the polymerization temperature can be decreased, and furthermore, the polymerization time can be reduced and thus is preferable. Polymerization temperature may be selected from any temperature, provided that the temperature is equal to or higher than the minimum radical generation temperature of polymerization initiator, and for example, 50 degree to 90 degree may be employed. However, polymerization can be carried out at a room temperature or temperature not less than the room temperature by employing a polymerization initiator for initiating at a room temperature, for example, a combination of hydrogen peroxide—reducing agent (ascorbic acid or the like). (Surfactant) In particular in order to carry out mini-emulsion polymerization by using the above-mentioned polymerization monomer, a surfactant is preferably used to carry out the drop oil dispersion in the water type medium. The surfactants available in this case are not particularly limited, and the following ionic surfactant can be illustrated for examples of the preferable compound. Ionic surfactant may include, for example, sulfonates (sodium dodecylbenzenesulfonate, sodium aylalkylpolyethersulfonate, 3,3-disulphonediphenylureα-4,4-diazo-bis-amino-8-naphthol-6-sodiumsulfonate, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sodium sulfonate or the like), sulfuric ester salts (sodium dodecylsulfate, sodium tetradecylsulfate, sodium pentadecylsulfate, sodium octylsulphate or the like), and fatty acid salt (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate or the like). Further, nonionic surfactant can also be employed. More specifically, for example, polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, ester with polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and polypropylene oxide, sorbitan ester or the like, can be employed. Although these surfactants are used as emulsifying agents mainly in the emulsifying polymerization process, these may be used for other steps or other purposes. (Molecular Weight Distribution of Resin particles and Toner) The toner according to the present invention may have a molecular weight distribution having a peak or shoulder within a range of 100,000 to 1,000,000, and preferably within a range of 1,000 to 50,000, and more preferably having a peak or shoulder within a range of 100,000 to 1,000,000, 25,000 to 150,000 and 1,000 to 50,000. Concerning the molecular weight of the resin particles, it is preferable to contain at least both of high molecular weight component having a peak or shoulder of the molecular weight distribution within a range of 100,000 to 1,000,000 and low molecular weight component having a peak or has shoulder of the molecular weight distribution within a range of from 1,000 to less than 50,000. It is more preferable to employ medium molecular weight resin having a peak or shoulder of the peak molecular weight distribution within a range of 15,000 to 100,000. The method for measuring the molecular weight of the toner or resin may preferably be the GPC (gel permeation chromatography) measurement utilizing a solvent of THF (tetrahydrofuran). That is, 1.0 ml of THF is added to 0.5 to 5 mg of, and more specifically 1 mg of, the test sample, and the mixtures are stirred using a magnetic stirrer at a room temperature to fully dissolve thereof. Then, after processed with a membrane filter having the pore size of 0.45 to 0.50 μm, the resultant product is injected into the GPC. The measurement condition of the GPC may be that the column is stabilized at 40 degree C., THF is introduced at a flow rate of 11.0 ml per minute, and about 100 μl of the sample having a concentration of 1 mg/ml is injected therein to conduct the measurement. It is preferable to use the column combined with the commercially available polystyrene gel column. For example, combination of Shodex GPC KF-801, 802, 803, 804, 805, 806 and 807 commercially available from Showa Denko Co., Ltd. or combination of TSK gel G1000H, G2000H, G3000H, G4000H, G5000H, G6000H, G7000H and TSK guard column commercially available from Tosoh Co., Ltd. or the like can be illustrated. Further, as detector, an UV detector or a refractive index detector (IR detector) may be employed. In the measurement of molecular weight of the sample, the molecular weight distribution that the sample has may be calculated using a calibration curve obtained by using mono-dispersing polystyrene standard particle. It is preferable to use about 10 kinds of the polystyrene particles for obtaining the calibration curve. (flocculant) The flocculant used for the present invention may preferable be selected from metal salts. The metal salts may include salts of monovalent metal such as, for example, alkali metal such as sodium, potassium, lithium or the like, salts of divalent metal such as, for example, alkaline earth metal such as calcium, magnesium or the like, divalent metal salts of such as manganese, copper or the like, and trivalent metal salts of such as iron, aluminum or the like. The specific examples of these metal salts will be shown below. Specific examples of the metal salts of monovalent metal may include sodium chloride, potassium chloride, lithium chloride or the like; and specific examples of the metal salts of divalent metal may include calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate or the like. Specific examples of the metal salts of trivalent metal may include aluminum chloride, iron chloride or the like. These are appropriately selected according to the objects. Generally, the critical aggregation concentration (coagulation value or coagulation point) is smaller for the metal salts of divalent metal than that for the metal salts of monovalent metal, and furthermore, the critical aggregation concentration of metal salts of trivalent metal is smaller. The critical aggregation concentration used in the present invention is an indicator for the stability of the dispersed matter in aqueous dispersion, and indicates a concentration thereof at a point of commencing the aggregation by adding a flocculant therein. This critical aggregation concentration significantly changes depending on the type of the latex itself and the type of the dispersing agent. For example, this is described by Seizo Okamura et al., KOBUNSHI KAGAKU (Polymer Chemistry), 17,pp. 601 (1960), and the value can be known according to these descriptions. Further, as an alternative method, it is possible to define the critical aggregation concentration as a salt concentration of the point, where ζ potential starts to change, by adding a desired salt into the targeted particle dispersion liquid with different concentration of the salt to measure ζ potential of the dispersion liquid. In the present invention, polymer fine particle dispersion liquid is processed so that the concentration thereof is equal to or higher than the critical aggregation concentration by using the metal salt. In this occasion, needless to say, it is arbitrarily selected according to the object thereof whether metal salt is directly added or aqueous solution is added. When the adding process is conducted via the aqueous solution, it is necessary for the concentration of the added metal salt to be equal to or higher than the critical aggregation concentration of polymer particle over the volume of the polymer particle dispersion and the total volume of the metal salt aqueous solution. The concentration of the metal salt as the flocculant in the present invention may be equal to or higher than the critical aggregation concentration, and preferably equal to or higher than 1.2 times of the critical aggregation concentration, and more preferably equal to or higher than 1.5 times. (Colorant) The toner according to the present invention is obtained by salting out/fusing the above-described composite resin particles and the colorant particles. The colorants composing the toner according to the present invention (the colorant particles which are presented for being salted out/fused with the composite resin particles) may be various inorganic pigments, organic pigments, color or the like. Conventionally known inorganic pigments may be employed. Specific inorganic pigments are exemplified as follows. As the black pigments, for example, carbon black such as furnace black, channel black, acetylene black, thermal black, lamp black or the like, and further, magnetic powder such as magnetite or ferrite may be employed. One of these inorganic pigments can be selected alone to be employed, or the combination of these inorganic pigments can be simultaneously employed, as desired. Further, the quantity of addition of the pigments may be 2 to 20 mass % over polymer, and preferably 3 to 15 mass % may also be selected. When it is used as magnetic toner, the above-mentioned magnetite can be added. In this case, in view of providing the predetermined magnetic characteristics thereto, it is preferable to add 20 to 60 mass % thereof into the toner. Conventionally known organic pigments and colors may also be employed. Specific organic pigments and colors are exemplified as follows. As pigments for magenta or red, for example, C.I. pigment red 2, C.I. pigment red 3, C.I. pigment red 5, C.I. pigment red 6, C.I. pigment red 7, C.I. pigment red 15, C.I. pigment red 16, C.I. pigment red 48:1, C.I. pigment red 53:1, C.I. pigment red 57:1, C.I. pigment red 122, C.I. pigment red 123, C.I. pigment red 139, C.I. pigment red 144, C.I. pigment red 149, C.I. pigment red 166, C.I. pigment red 177, C.I. pigment red 178, C.I. pigment red 222 or the like can be listed. As pigments for orange or yellow, for example, C.I. pigment orange 31, C.I. pigment orange 43, C.I. pigment yellow 12, C.I. pigment yellow 13, C.I. pigment yellow 14, C.I. pigment yellow 15, C.I. pigment yellow 17, C.I. pigment yellow 93, C.I. pigment yellow 94, C.I. pigment yellow 138, C.I. pigment yellow 180, C.I. pigment yellow 185, C.I. pigment yellow 155, C.I. pigment yellow 156 or the like can be listed. As pigments for green or cyanogen, for example, C.I. pigment blue 15, C.I. pigment blue 15:2, C.I. pigment blue 15:3, C.I. pigment blue 16, C.I. pigment blue 60, C.I. pigment green 7 or the like can be listed. Further, as colors, for example, C.I. solvent red 1, C.I. solvent red 49, C.I. solvent red 52, C.I. solvent red 58, C.I. solvent red 63, C.I. solvent red 111, C.I. solvent red 122, C.I. solvent yellow 19, C.I. solvent yellow 44, C.I. solvent yellow 77, C.I. solvent yellow 79, C.I. solvent yellow 81, C.I. solvent yellow 82, C.I. solvent yellow 93, C.I. solvent yellow 98, C.I. solvent yellow 103, C.I. solvent yellow 104, C.I. solvent yellow 112, C.I. solvent yellow 162, C.I. solvent blue 25, C.I. solvent blue 36, C.I. solvent blue 60, C.I. solvent blue 70, C.I. solvent blue 93, C.I. solvent blue 95 can be employed, and mixtures thereof can also be employed. One of these organic pigments and colors can be selected alone to be employed, or the combination of these organic pigments and colors can be simultaneously employed, as desired. Further, the quantity of addition of the pigments may be 2 to 20 mass % over polymer, and preferably 3 to 15 mass % may also be selected. Colorants (colorant particles) composing the toner may be surface-reformed. As surface reforming agents, conventionally a known surface reforming agents can be used, and more specifically, silane coupling agents, titanium coupling agents, aluminum coupling agents or the like may preferably be employed. Silane coupling agent may include, for example, alkoxysilanes such as methyl trimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane, of diphenyldimethoxysilane or the like, siloxane such as hexamethyldisiloxane or the like, γ-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureidepropyltriethoxysilane or the like. Titanium coupling agent may include, for example, TTS, 9S, 38S, 41B, 46B, 55, 138S, 238S, with the brand name of “PLENACT” commercialy available from Ajinomoto Co., Ltd., and A-1, B-1, TOT, TST, TAA, TAT, TLA, TOG, TBSTA, A-10, TBT, B-2, B-4, B-7, B-10, TBSTA-400, TTS, TOA-30, TSDMA, TTAB, TTOP, commercially available from Nippon Soda Co., Ltd. Aluminum coupling agents may include, for example, “PLENACT AL-M”, commercially available from Ajinomoto Co., Ltd. The quantity of adding of these surface reforming agents may preferably be 0.01 to 20 mass % over the colorant, and more preferably 0.1 to 5 mass %. The surface reforming methods for the colorant particles may include a method for adding the surface reforming agent into the dispersion liquid of colorant particles, and heating the system to induce a reaction. The surface reformed colorant particles are recovered via the filtration processing, and after the cleaning processing and the filtration processing with using the same solvent are repeated, these are dry processed. (Mold Releasing Agent) The toner used for the present invention may be preferably be the toner, which is formed by fusing the resin particles containing the mold releasing agent therein within the water type medium. As such, the toner having the mold releasing agent finely dispersed therein can be obtained by salting out/fusing the resin particles containing the mold releasing agent within the resin particles with the colorant particles in the water type and medium. For the toner according to the present invention, low molecular weight polypropylene (number average molecular weight=1,500 to 9,000) and low molecular weight polyethylene are preferable the for the mold releasing agent, and the ester compounds shown as the following formula are particularly preferable. R1—(OCO—R2)n In the formula, n represents an integer number of 1 to 4, preferably 2 to 4, more preferably 3 to 4, and particularly preferably 4. R1 and R2 represent hydrocarbon groups, each of which may have substituent. R1 has 1 to 40 carbons, preferably 1 to 20 carbons, and more preferably 2 to 5 carbons. R2 has 1 to 40 carbons, preferably 16 to 30 carbons, and more preferably 18 to 26 carbons. Next, examples of the typical compounds will be shown below. The quantity of adding the above compound may be 1 to 30 mass % over the whole toner, preferably 2 to 20 mass %, and more preferably 3 to 15 mass %. The toner according to the present invention may preferably prepared by incorporating the above-described mold releasing agent within the resin particles via the mini-emulsion polymerization method, and salting out/fusing them with the toner particle. (Charge Control Agent) Toner can include additional materials, which can provide various kinds of functions as the toner materials other than the colorants and mold releasing agents. More specifically, charge control agents can be added thereto. These components can be added via various methods such as a method of incorporating the resin particles and the colorant particles by simultaneously adding the resin particles and the colorant particles at the stage of the above-mentioned salting out/fusing stage, a method of adding thereof to the resin particles themselves or the like. Various known charge control agent capable of being dispersed in the water can be employed. More specifically, nigrosine type colors, metal salts of naphthenic acid or higher fatty acid, amine alkoxylate, quaternary ammonium salt compounds, azo metallic complexes, salicylic acid metal salts, or the metallic complexes thereof may be illustrated. (External Addition Agent) So-called external addition agent may be added to the toner according to the present invention for using the toner, in order to improve the flowability and improve the cleaninability. These external addition agents are not particularly limited, and various inorganic fine particles, organic fine particles and lubricants can be used. As the inorganic fine particles available as the external addition agents, conventionally known external addition agents can be illustrated. More specifically, silica fine particle, titanium fine particle, alumina fine particle or the like can be employed. These inorganic fine particles are preferably hydrophobic. Specific examples of the silica fine particles may be R-805, R-976, R-974, R-972, R-812 and R-809 commercially available from Japan Aerosil Co., Ltd., HVK-2150 and H-200 commercially available from Hoechst, TS-720, TS-530, TS-610, H-5 and MS-5 commercially available from Cabot and so on. Specific examples of titanium fine particles may be, for example, T-805 and T-604 commercially available from Japan Aerosil Co., Ltd., MT-100S, MT-100B, MT-500BS, MT-600, MT-600SS and JA-1, commercially available from Tayca Corp., TA-300SI, TA-500, TAF-130, TAF-510 and TAF-510T, commercially available from Fuji titanium Co., Ltd., IT-S, IT-OA, IT-OB and IT-OC, commercially available from Idemitsu Kosan Co., Ltd. or the like. Specific examples of alumina fine particles may be, for example, RFY—C and C-604 commercially available from Japan Aerosil Co., Ltd., TTO-55 commercially available from Ishihara Sangyo Kaisha or the like. Organic fine particles usable for the external addition agents may include spherical fine particles having a number average primary particle diameter of 10 to 2,000 nm level. The materials composing the organic fine particles may include polystyrene, olymethylmethacrylate, styrene-methylmethacrylate copolymer or the like. The lubricants usable for the external addition agent may include metal salts of higher fatty acid. Specific examples of metal salts of higher fatty acid may be: metal stearate such as zinc stearate, aluminum stearate, copper stearate, magnesium stearate, calcium stearate or the like; metal salt oleate such as zinc oleate, manganese oleate, iron oleate, copper oleate, magnesium oleate or the like; metal palmitate such as zinc palmitate, copper palmitate, magnesium palmitate, calcium palmitate or the like; metal linoleate such as zinc linoleate, calcium linoleate or the like; metal ricinoleate such as zinc ricinoleate, calcium ricinoleate or the like. The quantity of adding the external addition agent may preferably be 0.1 to 5 mass % level over the toner. (Step of Adding External Addition Agent) This step is a processing step, in which the external addition agent is added in the drγ-processed toner particles. Apparatus for using to add the external addition agents may include various known mixing equipment such as turbular mixer, henschel mixer, nauta mixer, V-type mixer or the like. (Toner Particle) Particle size of the toner may preferably be 3 to 10 μm as the number mean particle diameter, and more preferably 3 to 8 μm. The particle size can be controlled by adjusting the concentration of the flocculant (salting out agent), the quantity of the added organic solvent, the fusing time and the composition of polymer, in the process for manufacturing toner. Having the number mean particle diameter of 3-10 μm reduces the rate of the toner fine particles having larger adhesive force, which fly and are adhered to heating member to cause the offset in the fixing step, and further the transference efficiency increases, and the half-tone picture quality of improves and the picture quality in the filaments or dots improves. Number mean particle diameter of the toner can be measured by utilizing coulter counter TA-II, coulter multi-sizer SLAD1100 (laser diffraction type particle size measuring apparatus, commercially available from Shimadzu Co., Ltd.) or the like. In the present invention, the measurements were conducted by using the coulter multi-sizer, which is connected to an interface (commercially available from Nikkaki Co., Ltd.) that outputs the particle size distribution and to a personal computer. An aperture having a diameter of 100 μm was selected for the above-mentioned coulter multi-sizer to measure the volumetric distribution of toner of not smaller than 2 μm (for example, 2 to 40 μm), thereby calculating the particle size distribution and mean particle diameter thereof. (Range of Preferable Shape Factor of Toner Particle) The toner may contain equal to or more than 65 number % of the particles having the shape factor of 1.0 to 1.6, may preferably contain equal to or more than 65 number % of the particles having the shape factor of 1.2 to 1.6, and particularly preferably contain equal to or more than 70 number % of the particles having the shape factor of 1.2 to 1.6. The shape factor of the toner is determined by the following formula, and presents a degree of roundness of the toner particle. Shape factor=((maximum diameter/2)2×π)/projected area Here, the maximum diameter is determined to be a width of particle presented by a maximum space between parallel lines, when the projection image of the toner particle onto a plane is sandwiched with two parallel lines. The projection area is determined to be an area of the projection image of toner particle onto a plane. In the present invention, the shape factor was measured by picking up enlarged images of the toner particles magnified to 2000 times by utilizing a scanning electron microscope, and conducting an image analysis on the basis of the picked up enlarged images utilizing “SCANNING IMAGE ANALYZER” (commercially available from JEOL Co., Ltd.). In this occasion, 100 toner particles were used, and the shape factor of the present invention was measured with above formula for computation. As the toner according to the present invention, it is preferable to be a toner, in which sum (M) of the relative frequency (m1) of the toner particles contained in the most frequent hierarchy and the relative frequency (m2) of the toner particles contained in the second most frequent hierarchy that is next to the most frequent hierarchy is equal to or more than 70%, provided that the hierarchies appear in a histogram showing the particle size distribution of the number standard, which is divided in the abscissa into a plurality of hierarchies by interval of 0.23, and natural logarithm ln(D) is taken in abscissa when the particle size of the toner particles is presented as D (μm). Having the configuration, in which sum (M) of relative frequency (m1) and relative frequency (m2) is equal to or more than 70%, the variance of the size distribution of the toner particle becomes narrow, and therefore the prohibition of the generation of the selective development is ensured by employing the toner for the processing step of forming the image. The histogram showing the size distribution of the above-described number standard is a histogram showing the size distribution of number standard, dividing the natural logarithm ln(D) (D: particle size of individual toner particle) into a plurality of hierarchies with intervals of 0.23 (0 to 0.23: 0.23 to 0.46: 0.46 to 0.69: 0.69 to 0.92: 0.92 to 1.15: 1.15 to 1.38: 1.38 to 1.61: 1.61 to 1.84: 1.84 to 2.07: 2.07 to 2.30: 2.30 to 2.53: 2.53 to 2.76 . . . ). This histogram is prepared by forwarding the measured particle size data of the sample according to the following condition by using a coulter multi-sizer via I/O unit to a computer, and operating a size distribution analysis program in the computer. [Measurement Condition] 1: Aperture: 100 μm 2: Sample preparation method: an appropriate amount of a surfactant (neutral detergent) is added to 50 to 100 ml of electrolytic solution (ISOTON R-11 (commercially available from Coulter Scientific Japan Co., Ltd.)) and the mixture is stirred, and then 10 to 20 mg of the test sample is added. This system is dispersion-processed with an ultrasonic dispersion machine for one minute to prepare the sample. (Developer) The toner may be employed as either of one component developer or two component developer. When the developer is employed as one component developer, the developer may include a nonmagnetic one component developer, or a magnetic one component developer prepared by incorporating magnetic particles of having diameters of 0.1 to 0.5 μm level in the toner, and either of these developers may be employed. Further, these one component developers may be mixed with a carrier to prepare a two component developer. In this case, as the magnetic particle of carrier, conventionally known material including metals such as iron, ferrite, magnetite or the like, alloys with the above-described metals and metals such as aluminum, lead or the like can be employed. In particular, ferrite particles are preferable. The above-described magnetic particle may have a volumetric mean particle diameter of 15 to 100 μm, and more preferably 25 to 80 μm. Measurements of the volumetric mean particle diameter of the carrier typically may be carried out by utilizing a laser diffraction particle size distribution measurement apparatus comprising a wet process disperser “HELOS” (commercially available from SYMPATEC Co., Ltd.). As for the carrier, a carrier having magnetic particles coated with a resin, or a so-called resin distributed carrier, which is prepared by dispersing the magnetic particles in a resin, is preferable. The resin composition for the coating is not particularly limited, and the available resins for the use may include, for example, olefin type resins, styrene type resins, Styrene-acryl type resins, silicone type resins, ester type resins, or fluorine content polymer type resin or the like. Further, resins for composing the resin dispersing type carrier is not particularly limited and conventionally known resins, for example, styrene-acryl type resins, polyester resins, fluorine type resins, phenolic resins or the like, can be used. (Image Forming Method) The toner according to the present invention may suitably be employed for an image formation method, which comprises a step of fixing the image by passing an image formation base member having a toner image formed thereon between the heating roller 1 and the endless belt 2 that compose the fixing apparatus described in reference with FIGS. 1 and 2. (Image Forming Method and Apparatus) FIG. 3 is a cross-sectional view of an example of an image forming apparatus for embodying the image forming method of the invention. In FIG. 3, the reference numeral 50 denotes a photoreceptor drum (a photoreceptor) which is an image bearable body. The photoreceptor is prepared by applying an organic photosensitive layer onto the drum, and further by applying a resinous layer onto the resultant photosensitive layer. The drum is grounded and rotated clockwise. Reference numeral 52 is a scorotron charging unit (charging means) which uniformly charges the circumferential surface of photoreceptor drum 50 via corona discharge. Prior to charging, employing the charging unit 52, in order to eliminate the hysteresis of the photoreceptor due to the previous image formation, the photoreceptor surface may be subjected to charge elimination through exposure, employing a precharge exposure section 51 comprised of light emitting diodes. After uniformly charging the photoreceptor, image exposure is carried out based on image signals employing an image exposing unit 53. The image exposing unit 53 comprises a laser diode (not shown) as the exposure light source. Scanning onto the photoreceptor drum is carried out employing light of which light path has been deflected by a reflection mirror 532 through a rotating polygonal mirror 531, fθ lens, and the like, and thus an electrostatic latent image is formed thereon. The reversal developing process in this invention is an image formation method in which the surface of the photoreceptor is uniformly charged by the charging unit 52, and a portion on which image exposure is carried out, that is, an exposed portion potential of the photoreceptor (image exposed portion) is developed through a developing process (method). A non-image exposed portion is not developed since developing bias potential is applied to the photoreceptor by a developing sleeve 541. The resultant electrostatic latent image is subsequently developed in the development unit 54. The development unit 54, which stores the developer material comprised of a carrier and a toner, is disposed adjacent to the outer peripheral surface of the photoreceptor drum 50. The development is carried out employing the development sleeve 541, internally comprises magnets and rotates while bearing the developer material on its outer peripheral surface. The interior of the developer unit 54 comprises a developer material stirring member 544, a developer material conveying member 543 and a conveying amount regulating member 542. Thus, the developer material is stirred, conveyed and supplied to the development sleeve. The supply amount is controlled by the conveying amount regulating member 542. The conveyed amount of the developer material varies depending on the linear speed of an applied organic electrophotographic photoreceptor as well as its specific gravity, but is commonly in the range of 20 to 200 mg/cm2. The amount of the developer material is regulated employing the conveying amount regulating member, and then conveyed to the development zone, where the latent image developed therewith. At that time, development may be carried out while direct current bias voltage, if desired, alternative current bias voltage is applied to the space between photoreceptor drum 50 and development sleeve 541. In this case, the developer material is subjected to development in a contact or non-contact state with the photoreceptor. The potential of the photoreceptor may be carried out above the developing zone by using a potential sensor 547. A recording paper P is supplied to the transfer zone by the rotation of paper feeding roller 57, when timing for transfer is properly adjusted. In the transfer zone, a transfer electrode (transfer section: transferring device) 58 provided adjacent to the peripheral surface of the photoreceptor drum 50 is activated in synchronous with the transferring timing to perform the image transfer onto the recording paper P which has been introduced between the photoreceptor drum 50 and the transfer electrode 58. Subsequently, the resultant recording paper P is subjected to charge elimination, employing separation electrode (the separation unit) 59 which has been activated almost concurrently with activation of the transfer electrode 58. Thus, the recording paper P is separated from the circumferential surface of photoreceptor drum 50, and conveyed to a fixing unit 60. Then, after the toner is fused under heat and pressure, the resulting recording paper P is ejected to the exterior of the apparatus. Further, after passage of the recording paper P, the transfer electrode 58 and the separation electrode 59 are retracted from the circumferential surface of photoreceptor drum 50, and is prepared for the formation of subsequent toner images. In FIG. 3, a corotron electrode is used as the transfer electrode 58. The operating condition of the transfer electrode varies with the process speed (peripheral speed) of the photoreceptor drum 50 and are not specifically specified. Generally, however, the transfer current is in the range of, for example, +100 to +400 μA, and the transfer voltage is in the range of, for example, from +500 to +2,000 V. On the other hand, the photoreceptor drum 50, from which recording paper P has been separated, is subjected to removal of any residual toner and cleaning through pressure contact with a blade 621 of a cleaning unit 62, and then subjected to charge elimination by precharge exposure section 51, as well as subjected to charging employing the charging unit 52. The photoreceptor drum 50 then enters the next image forming process. Reference numeral 70 denotes a detachable process cartridge, which is integrally comprised of the photoreceptor, the charging unit, the transfer unit, the separation unit, and the cleaning unit. The organic electrophotographic photoreceptor of the invention can generally be applied to electrophotographic apparatuses, laser printers, LED printers, liquid crystal shutter type printers, and the like, and can further be widely applied to apparatuses such as displays, recording media, small volume printing, plate making, facsimile production, and the like, to which common electrophotographic techniques are applied. Concerning the fixing method, description has been made in reference to FIGS. 1 and 2 in detail before, and supplementary description on other features thereof will be made as follows. A metal core 3 preferably has the inside diameter of 10 to 70 mm and also preferably has the wall thickness of 0.1 to 15 mm, and these are determined in consideration of the balance between the requirement for the energy saving (reduction of the wall thickness) and the requirement for the strength (depending upon the composing material). For example, in order to maintain strength equivalent to that of a core consisting of iron of 0.57 mm thick by utilizing a core metal consisting of aluminum, it is preferable to have the wall thickness of 0.8 mm. The thickness of the fluorine resin layer composing the releasing layer 5 may be 10 to 500 μm, and preferably 20 to 400 μm. If the thickness of the releasing layer 5 is less than 10 μm, the functions as the releasing layer cannot be fully presented, and thus the durability as the fixing apparatus cannot be ensured. On the other hand, if 500 μm is exceeded, the heat conduction of the heating roller is reduced, and thus surface temperature of the roller cannot be uniformly controlled. As the contacting load (total load) of the heating roller 1 with the pressure roller 6 may usually be 40 to 350 N, preferably 50 to 300 N, and more preferably 50 to 250 N. This contacting load is determined in consideration with the strength of the heating roller 1 (wall thickness of the core 3), and for example, it is preferable to determine equal to or less than 250N for the heating roller having the core consisting of iron of 0.3 mm thick. Further, in view of the offset resistance and fixing properties, the nip width may be preferably 4 to 10 mm, and the bearing of the nip may preferable be 0.6×105 Pa to 1.5×105 Pa. An example of the fixing condition for the fixing apparatus shown in FIGS. 1 and 2 may be that the fixing temperature (surface temperature of the heating roller 1) is 150 to 210 degree C., and the fixing linear velocity is 80 to 640 mm/sec. The fixing apparatus for using in the present invention may be provided with a cleaning mechanism as required. In this case, available method is that silicone oil is supplied to the upper roller (heating roller) on the fixing member by the method of supplying a pad roller, web or the like impregnating silicone oil therein to clean thereof. Available silicone oil may be a silicone oil having higher resistant to heat, and poly dimethylsiloxane, polyphenyl methylsiloxane, poly diphenyl siloxane or the like may be used. Since silicone oil having lower viscosity provides larger discharging flow in the operation, silicone oil having a viscosity of 1 to 100 Pa sec in 20 degree C. may preferably be employed. Nevertheless, the advantageous effect of the present invention is considerably exhibited in particular in the case of having a step of forming an image by using a fixing apparatus, in which no silicone oil is supplied thereto or the quantity of feeding of silicone oil is extremely low. Accordingly, even if silicone oil is supplied therein, feeding quantity thereof may preferably be equal to or less than 2 mg per one A4 sheet paper. By having a feeding quantity of silicone oil as equal to or less than 2 mg per one A4 sheet paper, the adhesion of silicone oil on the transfer paper (image support) after the fixing process is reduced, and the disturbance for the writing with an oiliness pen such as a ball point pen by the silicone oil adhered to transfer paper is reduced, and thus the writing-ability is not spoiled. Further, a problem of the decrease of the offset resistance by time due to the decomposition of silicone oil, and a problem of contamination of the optical system and the charging pole by silicone oil can be prevented. Here, a feeding quantity of silicone oil can be calculated by passing 100 sheets of the transfer papers (a blank paper of A4 size) in succession through the fixing apparatus (between rollers) which is heated to a predetermined temperature, and the variation in the mass (Δw) of the fixing apparatus before and after passing the paper sheets, and thus the feeding quantity is calculated (Δw/100). The present invention will be described by illustrating examples more specifically as follows, and it is not intended that the present invention is limited to these examples. ((Preparation of Various Deodorizers)) According to the method described below, deodorizers 1 to 4 were prepared. <Deodorizer 1: Deodorizer Containing Plant Extracted Component> Deodorizer 1 was prepared by dissolving 10 g of F118 (commercially available from Fine 2 Co., Ltd.), which is a commercially available deodorizer containing plant extracted component, into 2 kg of ion-exchange water at 40 degree C. <Deodorizer 2: Enzyme Type Deodorizer> Deodorizer 2 was prepared by dissolving 5 g of Bio Dash P-500 (commercially available from Daiso Co., Ltd.) into 2 kg of ion-exchange water at 40 degree C. <Deodorizer 3: Enzyme Type Deodorizer Containing Plant Extracted Component> Deodorizer 2 was prepared by dissolving 5 g of Bio C (commercially available from Console Corporation), which is a commercially available deodorizer containing plant extracted component into 2 kg of ion-exchange water at 40 degree C. (Deodorizer 4: Amyris Oil Type Deodorizer) Deodorizer 4, which is an emulsion, was prepared by dispersing 2 g of amyris oil into 200 ml of ion-exchange water containing surfactant. ((Preparation of Toner and Developer)) (Preparation of Resin Particle) [Preparation of Resin Particle 1HML] <1: Preparation of Nuclear Particle (First Step of Polymerization)> A surfactant solution (water type medium) containing 7.08 g of anionic type surfactant “A” (C10H21 (OCH2CH2)2 OSO4Na) dissolved in 3010 g of ion-exchange water was poured into a separable flask of 5000 ml, to which a stirrer, a temperature sensor, a cooling pipe and a nitrogen introduction unit were installed, and temperature was increased to 80 degree C. while stirring with agitation rate of 230 rpm and flowing nitrogen gas stream therein. An initiator solution containing 9.2 g of polymerization initiator (potassium persulfate: KPS) dissolved in 200 g of ion-exchange water is added into this surfactant solution, and after increasing the temperature to 75 degree, a monomer liquid mixture composed of 70.1 g of styrene, 19.9 g of N-butylacrylate and 10.9 g of methacrylic acid was dropped for one hour, Polymerization (first step polymerization) is conducted by heating and stirring this system for two hours at 75 degree C. to prepare resin particles (a dispersion liquid of resin particles consisting of high molecular weight resin). These were assigned as “resin particle (1H)”. <2: Formation of Interlayer (Second Step Polymerization)> 98.0 g of the above-listed compound 19) as mold releasing agent was added in a monomer liquid mixture composed of 105.6 g of styrene, 30.0 g of N-butylacrylate, 15.4 g of methacrylic acid and 5.6 g of N-octyl-3-mercaptopropionate ester in a flask equipped with a stirrer, and heating and dissolving were conducted at 90 degree C. to prepare monomer solution 1. Subsequently, the surfactant solution containing 1.6 g of above-mentioned anionic surfactant “A” dissolved in 2700 ml of ion-exchange water is heated to 98 degree C., and after 28 g with solid content conversion of the above-mentioned resin particles (1H), which is the dispersion liquid of the nuclear particles, was added in this surfactant solution, the above-mentioned prepared monomer solution 1 is mixed and dispersed by using a stirring apparatus “CLEARMIX”, that comprises a circulating path (commercially available from M-Technique Co., Ltd.) to prepare an emulsion which included emulsification particles having a uniformly dispersed particle diameter (284 nm). Subsequently, an initiator solution containing 5.1 g of polymerization initiator (KPS) dissolved in 240 ml of ion-exchange water and 750 ml of Ion-exchange water were added into this emulsion, and polymerization (second step polymerization) was conducted by heating and stirring this system for 12 hours at 98 degree C. to obtain resin particles (a dispersion liquid of composite resin particle having a structure, in which the surface of the resin particles composed of high molecular weight resin was coated with medium molecular weight resin). These were assigned as “resin particle (1HM)”. The above-mentioned resin particles (1HM) were dried and were observed with scanning electron microscope, and particles (400 to 1,000 nm) comprising a main component of the above-listed compound 19) that was not surrounded by latex were observed. <Formation of Outer Layer (Third Step Polymerization)) The initiator solution containing 7.4 g of polymerization initiator (KPS) dissolved in 200 ml of ion-exchange water was added to the above-mentioned prepared resin particles (1HM), and a monomer liquid mixture composed of 300 g of styrene, 95 g of N-butylacrylate, 35.4 g of methacrylic acid and 10.4 g of N-octyl-3-mercaptopropionate ester was dropped thereto for one hour at a temperature condition of 80 degree C. After the dropping processing was completed, polymerization (third step polymerization) was carried out by heating and stirring for two hours, and thereafter the system was cooled to 28 degree C. to obtain resin particles (a dispersion liquid of composite resin particles comprising cores consisting of high molecular weight resin, inter-layers consisting of medium molecular weight resin, and outer layers consisting of low molecular weight resin, and the above-listed compound 19) is contained in the interlayer as mold releasing agent). These resin particles were assigned as “resin particle (1HML)”. The composite resin particles composing the resin particles (1HML) has a molecular weight distribution having the peak molecular weights at 138,000, 78,000 and 14,500, and the mass mean particle diameter of the composite resin particles was 124 nm. [Preparation of Resin Particle (2HML)] Resin particles (a dispersion liquid of composite resin particles having cores consisting of high molecular weight resin, inter-layers consisting of medium molecular weight resin and outer layers consisting of low molecular weight resin) were prepared by process similar to the preparation process of the above resin particle (1HML), except that the adding quantity of methacrylic acid for the formation of interlayer (the second step polymerization) was changed from 15.4 g to 10.5 g, and except that, furthermore in formation of the outer layer (third step polymerization), the adding quantity of methacrylic acid was changed from 35.4 g to 18.5 g. These resin particles were assigned as “resin particle (2HML)”. The composite resin particles composing the resin particles (2HML) has a molecular weight distribution having the peak molecular weights at 118,000, 80,000 and 13,500, and the mass mean particle diameter of the composite resin particles was 110 nm. (Preparation of Toner) [Preparation of Toner Particles] <Preparation of Toner Particles 1 to 4> 59.0 g of anionic system surfactant “B” (sodium dodecyl sulfate) was added to 1600 ml of ion-exchange water and was stirred and dissolved. While stirring. this solution, 420.0 g of carbon black “Legal 330” (commercially available from Cabot Co., Ltd.) was gradually added, and subsequently, a dispersion liquid of colorant particles (hereinafter called “colorant dispersion liquid 1”) was prepared by conducting a dispersion processing using “CLEARMIX” (commercially available from M-Technique Co., Ltd.). A particle diameter of the colorant particles in the colorant dispersion liquid 1 was measured using an electrophoretic light scattering photometer “ELS-800” (commercially available from Otsuka Electronics Co., Ltd.), and the result was 98 nm by mass mean particle diameter. 420.7 g (solid content conversion) of the aforementioned prepared resin particles (1HML), 900 g of ion-exchange water and 166 g of the above prepared colorant dispersion liquid 1 were added into a reactor vessel (four neck flask) equipped with a temperature sensor, a cooling pipe, a nitrogen introduction apparatus and a stirring apparatus, and was stirred. After adjusting the temperature in the vessel at 30 degree C., 5 mol/l of sodium hydroxide aqueous solution was added to this solution, and pH was adjusted to 9.0. Subsequently, a step of adding water solution containing respective flocculants dissolved in 1000 ml of ion-exchange water by combinations described in table 2 was continued for 10 minutes while stirring thereof at 30 degree C. After leaving thereof for three minutes, temperature rising was started, and the temperature of this aqueous solution was increased for 30 minutes up to 90 degree C. to start the growth of the particles. The particle size of the associated particles were measured by utilizing “Coulter counter TA-II”, while maintaining this condition, and when the detected volumetric mean particle diameter was 4.0 μm, the water solution containing terminators listed in Table 2 dissolved in 1000 ml of ion-exchange water was added to stop the growth of the particles. Furthermore, heating and stirring thereof were continued as a maturing processing for 2 hours at a solution temperature of 98 degree C. to continue the fusing processing. Thereafter, the system was cooled down to 30 degree C. under the cooling condition of 8 degree C./minute. Subsequently, hydrochloric acid was added to adjust pH to 2.0, and the stirring was stopped. Generated associated particles were filtered by using a nutsche filter, and after repeatedly washed with ion-exchange water at 45 degree C., respective aforementioned prepared deodorizers were filtered through the nutsche filter with combinations shown in Table 2, and thereafter the filtered products were dried with a warm wind of 40 degree C. to prepare toner particles 1 to 4 of the present invention having components shown in Table 2. <Preparation of Toner Particle 5 to 7> Toner particle 5 to 7 were prepared by replacing the resin particles (1HML) with resin particles (2HML), and further changing the types and the adding quantities of the flocculants and the terminators and types of deodorizers as described in Table 2, from the preparation processes of above-described toner particle 1 to 4. <Preparation of Comparative Toner Particles 1> 55 parts by mass of polymer consisting of styrene and acrylic acid and having a peak at 3,000 in the molecular weight distribution, 20 parts by mass of polymer consist of styrene, butylacrylate and acrylic acid and having a peak at 100,000 in the molecular weight distribution and 25 parts by mass of polymer consisting of styrene and butylacrylate having a peak at 650,000 in the molecular weight distribution were uniformly blended in xylene. Xylene was removed by distillation at the reduced pressure, and the binder resin 1 was obtained. 100 parts by mass of the binder resin 1, 10 parts by mass of carbon black and 4 parts by mass of polypropylene wax were melted and kneaded by using a dual axis roll kneader, and thereafter, the kneaded compound was pulverized by using a jet mill. Subsequently, toner compound having a volumetric mean particle diameter of 8.5 μm was obtained by using an air classification apparatus. 1 part by mass of hydrophobic silica was added over 100 parts by mass of this toner composition and was mixed by using a dry mixer to obtain comparative toner particle 1. As results of the measurements of molecular weight distribution of this comparative toner particle 1 by utilizing gel permeation chromatography, the chromatogram had a profile having a main peak at molecular weight of 3,000, a peak at molecular weight of 500,000 and a shoulder at molecular weight of around 130,000. Low molecular weight component (LP) was 63 mass %, medium molecular weight component (MP) was 20 mass %, high molecular weight component (HP) was 17 mass %, and [Mpratio+2×HPratio] was 54 mass %. Further, the results of the measurement of the glass transition point of this comparative toner particle 1 presented that the glass transition temperature was 55 degree C. Here, the measurements of the glass transition temperature was carried out by using DSC, and the glass transition temperature was defined as an intersecting point of the base line and the gradient of the endotherm peak. More specifically, a differential scanning calorimetry was employed, and the temperature was increased to 100 degree C., and left them for three minutes at the temperature, and thereafter was cooled off to the room temperature with a cooling rate 10 degree C./min. Then, when the measurement of this sample was conducted under the condition of the temperature increasing rate of 10 degree C./min, an intersecting point of an extended line of the base line providing values equal to or less than the glass transition temperature and a tangential line showing a maximum gradient between the rising edge of the peak and the summit of the peak was defined as a glass transition temperature. Measuring apparatus of DSC-7, commercially available from Perkin Elmer was employed. TABLE 2 Flocculants Anticatalysts Adding Adding Deodorizing Agent Toner Particle No. Resin Particle No. Types Quantities (g) Types Quantities (g) No. 1 1 Magnesium Chloride 12.1 Sodium Chloride 80.4 1 + 3 Hexahydrate 2 1 Magnesium Chloride 24.2 Sodium Chloride 40.2 1 + 2 Hexahydrate 3 1 Magnesium Chloride 7.5 Sodium Chloride 56.1 1 Hexahydrate 4 1 Magnesium Chloride 12.1 — — 1 Hexahydrate 5 2 Calcium Chloride 36.1 Sodium Chloride 160.8 3 Hexahydrate 6 2 Aluminum Chloride 2.9 Calcium 4.0 4 Chloride 7 2 Aluminum Hydroxide 9.2 Sodium Chloride 80.4 3 + 4 (Measurements of Metal Salts a, b Content in Each of Toner Particles and Methacrylic Acid Content) Concerning each of the prepared toners described above, contents of metal salts a, b defined by claim 1 and claim 3 and contents of methacrylic acid were measured, and the obtained results are shown in Table 3. In addition to above, measurements of contents of metal salts a, b in each toner were conducted by using a X-ray fluorescence analysis apparatus “System 3270” (commercially available from Rigaku Denki Kogyo Co., Ltd.) to measure the intensity of fluorescent X-ray emitted from metal species of inorganic salts (for example, calcium from calcium chloride) and the intensity of fluorescent X-ray of base corresponding thereof. Further, the content of methacrylic acid was obtained by utilizing thermal decomposition gas chromatography. TABLE 3 Metallic Salt Contents of Monomer Contents Containing Carboxyl Group Toner No. a(%) b(%) a/b Metallic Salt Corresponding to a Metallic Salt Corresponding to b (%) 1 0.71 0.49 1.45 Magnesium Chloride Sodium Chloride 9 2 1.42 0.26 5.46 Magnesium Chloride Sodium Chloride 9 3 0.44 0.36 1.22 Magnesium Chloride Sodium Chloride 9 4 0.75 — — Magnesium Chloride Sodium Chloride 6 5 1.87 0.94 1.99 Calcium Chloride Sodium Chloride 6 6 0.12 0.02 6.00 Aluminum Chloride Calcium Chloride 6 7 0.44 0.39 1.13 Aluminum Hydroxide Sodium Chloride 9 Comparative — — — — — 0 Toner 1 (Preparation of Developer) As a developer, silicone coat carrier having a volumetric mean particle diameter of 60 μm was used, and was mixed with respective toners so that the toner concentration could be 6%. ((Image Formation and Evaluation of formed image)) (Image Formation) As a belt for pressurization, an object was formed by coating a rubber composition disclosed in Example 2 of JP-Tokukai 2001-60050 on a base member having an endless belt-shape made of polyimide to a thickness of 200 μm, and baking thereof at a temperature of 230 degree C. for three hours to form an elastic body layer 14 as shown in FIG. 2. A fixing unit shown in FIG. 2 was equipped with a halogen lamp of 800 W as an exothermic body 10 in the interior of a heating roller 1, and the processing conditions were set to: surface temperature of heating roller of 170 degree C., fixing speed of 220 mm/sec. and nip width of 10 mm. Further, a mold releasing agent application device for supplying mold releasing agent oil was provided on the surface of the heating roller. Unfixed toner images were introduced into the nip region formed by the heating roller 1 and the endless belt 2 and was passed therethrough, and each of the printed toner images on the base member by heat and pressure was fixed, and the fixing condition thereof were evaluated according to the following evaluations. Here, the toner density of the unfixed toner image was 1.5 mg/cm2. <Measurement of Range of Temperatures Available for Toner Fix> Temperature of fixing roll was changed by 10 degrees pitch within the range of 130 degree C. to 240 degree C. to provide the fixed images. Here, general paper of A4 size (grammage: 64 g/m2) was used for the use in the output of the fixed image. The fixing strength of the obtained fixed image was evaluated by a method according to the mending tape-peeling method described in “Denshishashin Gijutu No Kisoto Ohyoh (“Basics and Applications of The Electrophotography Technology): edited by the Japanese Electrophotography Institute, chapter 9 sub section 1.4”, and the fixing rate was evaluated. More specifically, after preparing a solid fixed image of 2.54 cm-square having a adhesion quantity of each toner of 0.6 mg/cm2, and image concentrations before and after the peeling by using a scotch mending tape (commercially available from Sumitomo 3M Co., Ltd.) to determine the remaining rate of the image concentration as the fixing rate. In measurement of image concentration, reflecting density indicator RD-918 commercially available from Macbeth Co., Ltd. was used, and the temperature available for toner fix was defined as the fixing temperature, at which the fixing rate of equal to or higher than 95% was obtained. Concerning the temperatures available for toner fix measured by the above-mentioned method, the ranges of temperatures available for toner fix were classified according to the criteria shown below. ⊚ (Excellent): range of temperature available for toner fix was equal to or more than 100 degree C.; ◯(good): range of temperature available for toner fix was equal to or higher than 70 degree C. and less than 100 degree C.; Δ(possible practical use): range of temperature available for toner fix was equal to or higher than 40 degree C. and less than 70 degree C.; and X(failure): range of temperature available for toner fix is less than 40 degree C. <Evaluation of offset resistance> After the printing processes were continuously carried out for 1,000 pieces of the A4 size transfer paper using each toner, a blank paper is printed, and the stain created on the blank paper due to the offset and the toner stain of the fixing member surface were observed with a visual observation. Here, heavy paper of the premium grade paper of 200 g/m2 was used as the transfer paper, and a line image of 0.3 mm wide and 150 mm long, which is parallel in paper advance direction (heating roller periphery direction), was formed, and the offset natures were evaluated according to the criteria described below. ⊚: Both the image offset and the toner stain of the heating roller were not recognized at all; ◯: The image offset was not be confirmed, but the toner stain was recognized on the heating roller; and X: Image offset was clearly confirmed. In above classifications, ⊚ and ◯ was judged that the practical use was possible, and X was judged that the practical use was not possible. <Evaluation of Duration Life of Fixing Member> It continuous printing was carried out under the condition described above, and the scale of the duration life of the fixing member was presented by the criteria of the number of processed sheets: in which the toner clagged on the endless belt or on the surface of the heating roller so that the it was impossible to clean thereof; or in which the image failure due to being peeled off begun to be detected on endless belt or the releasing layer of heating roller surface. <Evaluation of Odor in Toner Fixing> Evacuation filter was detached, and charts having image area of 7% were continuously printed for 1,000 sheets with each toner, using an electrophotographic apparatus having a fixing unit shown in FIG. 2, and concerning the fixing odor of the case, the odor was judged by 20 general panelists according to the following criteria. ⊚: odor was hardly recognized; ◯: odor was recognized inconsiderably, but there is not a feeling of unpleasantness in particular; X: odor with an unpleasant feeling was recognized. The obtained results according to above are shown in Table 4. TABLE 4 Range of Temperatures Available for Toner Odor Generation for Toner No. Fix Anti-Offset Lifetime of Fixing Material Fixing Process Miscellaneous 1 A ⊚ 200,000 sheets ⊚ Present Invention 2 B ⊚ 180,000 sheets ⊚ Present Invention 3 A ⊚ 180,000 sheets ⊚ Present Invention 4 B ◯ 100,000 sheets ◯ Present Invention 5 B ◯ 180,000 sheets ◯ Present Invention 6 B ◯ 160,000 sheets ◯ Present Invention 7 B ◯ 150,000 sheets ◯ Present Invention Comparative D X 30,000 sheets X Comparative Example Toner 1 As can be seen from Table 4, in the fixing method utilizing the heating fixing device having the endless belt capable of orbitally moving and the elastic body layer formed on the endless belt, by employing the toner which employs the polymer toner particles containing the deodorizer according to the present invention, better range of temperature available for toner fix, and better the offset resistance than the comparative example are provided, long duration life of the fixing member is provided and the odor is hardly emitted in the toner fixing process. | <SOH> BACKGROUND <EOH>1. Technical Field The present invention relates to an image forming method, which is applicable to a photocopying machine, a printer, a facsimile equipment or the like, and in which an electrostatic latent image is formed on an image support member, and the formed electrostatic latent image is developed with toner, and pictorial image is formed. 2. Description of Related Art Conventionally, in the copying machine which utilizes an electrophotography process, it is necessary to fix an unfixed toner image formed on the recording sheet to form an eternity image, and a heating roller fixing method conducted by the heating and the pressurization is a general fixing method. That is, a known apparatus is a heating roller type fixing apparatus, which comprises: a heating roller which comprises a heater lamp within a cylindrical core metal and a heat resistant releasing layer formed on the outer surface thereof; and a pressure roller which is disposed in a compressibly contacting manner against this heating roller (fixing roll), and comprises a heat-resistant elastic body layer formed on outer surface of the cylindrical core metal, wherein a fixing process is conducted by applying a constant pressure between both these rollers and inserting therebetween a support member such as normal paper on which an unfixed toner image is formed. Because the heating roller type fixing apparatus used for this system has higher thermal efficiency, in comparison with other heating fixing methods such as a flash fixing system and an oven fixing system, and thus requires lower electric power, provides better processing speed, and also provides lower fire-hazardous nature caused by a paper jam, the heating roller type fixing apparatus is the most popular system at the present time. However, since the fixing apparatus of the heating roller fixing system using the heating roller (rotating part materials for fixing) requires to heat the heating roller for fixing having larger heat capacity, when transference materials and the toner are heated with the heating roller having halogen heater therein, it is disadvantageous for the energy conservation effect, and thus it provides poor energy conservation, and further, since time consumes for warming up the fixing apparatus in a printing process, there is problem of requiring longer printing time (warming up time). In recent years, there is a demand for increasing the fixing rate in such heating roller type fixing apparatus, and in order to satisfy the demand, the width of the nip region, or in other words the nip width, is required to be increased. Here, methods for increasing the nip width include a method for increasing the load exerted between these rollers, or a method for increasing roller diameter of both the fixing roller and the pressure roller, or the like. However, there is a limitation in the available fixing rate that can correspond with these methods, and in order to apply for the higher fixing rate region, a heating roller belt type fixing apparatus is developed. Pressurizing belts employed for the heating roller belt type fixing apparatus as mentioned above may mainly and be classified into two types of belts, in general. More specifically, the belts are classified into: 1) fluorine resin-coated belt, which is formed by coating the base film of endless belt shape with an adhesive referred to as “primer”, and thereafter thinly coating thereof with a fluorine resin such as polytetrafluoroethylene (PTFE) or copolymer of tetrafluoroethylene and perfluoroethylene (PFA) and so on; and 2) silicone rubber coating belt or fluorine-containing rubber coating belt, which is formed by thinly coating the base film having endless belt shape with silicone rubber or fluorine-containing rubber via a primer therebetween. As the fixing system that employs the metal belt (belt member) having the above mentioned rubber layer, and has an exothermic roller (exothermic roller member), which heats the belt member and provided in the inside of belt member, is disclosed in, for example, JP-Tokukai 2000-267356, JP-Tokukai 2000-60050 and JP-Tokukai 09-138599. However, the above-mentioned proposed fixing apparatus, which uses endless belt, has a drawback of having lower fixing strength due to its lower fixing load (pressurization) as compared with the heating roller system, and among other things, there are various problems of varying the fixing strength depending on the types of the toner and the transfer paper, and thus it is the present situation that does not reach to apply the fixing apparatus containing this system to the application of a high speed printer and a high speed photocopying machine. Furthermore, since the above-mentioned fixing system involves heating the toner image, a minor constituent included in the toner is released into the atmosphere, and there is a case, which causes an unpleasant odor for the users. More in recent years, accompanying with the reduction of the size of the photocopying machine and the printer, opportunity of using them with intimacy becomes increasingly in offices. In addition, the opportunity of using such machines in general families have been increased, and as a result, the case, in which odor emitted from the toner gives an unpleasant feeling to the user, increases more often than conventional. | <SOH> SUMMARY <EOH>In accordance with the first aspect of the present invention, an image forming method comprises: fixing an image formed by a toner on a record sheet in a nip member formed by a pressurizing member which is compressibly contacted against a heating fixing rotor having an elastic body layer formed on an endless periphery surface capable of orbitally moving and which creates locally a large distortion occurred in the elastic body layer in vicinity of outlet thereof, wherein the toner includes at least two metal salts having different valence and has a relationship given by the Formula (1). in-line-formulae description="In-line Formulae" end="lead"? 2.0≧a≧0.1 in-line-formulae description="In-line Formulae" end="tail"? in-line-formulae description="In-line Formulae" end="lead"? 1.0≧b≧0.01 in-line-formulae description="In-line Formulae" end="tail"? in-line-formulae description="In-line Formulae" end="lead"? 7.5≧ a/b ≧1.1 Formula (1) in-line-formulae description="In-line Formulae" end="tail"? wherein a (mass %) is defined as a content of a metal salt which is contained at a highest content in total toner mass and b (mass %) is defined as a content of a metal salt which is contained at a second-highest content in the total toner mass, and mass values of a and b represent anhydride reduced values. In accordance with the second aspect of the present invention, an image forming method comprises: fixing an image formed by a toner on a record sheet in a nip member formed by a pressurizing member which is compressibly contacted against a heating fixing rotor having an elastic body layer formed on an endless periphery surface capable of orbitally moving and which creates locally a large distortion occurred in the elastic body layer in vicinity of outlet thereof, wherein the toner is one manufactured by salting out/fusing resin particles. By use of the first and second aspects of the present invention, a image forming method having wider range of temperature available for toner fixing, better anti-offset, longer duration life of the fixing member and reduced odor emitted in the fixing process can be provided. | 20040412 | 20070710 | 20051013 | 95499.0 | 0 | CHAPMAN, MARK A | IMAGE FORMING METHOD | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,823,508 | ACCEPTED | Determining and/or using location information in an ad system | The usefulness, and consequently the performance, of advertisements are improved by allowing businesses to better target their ads to a responsive audience. Location information is determined (or simply accepted) and used. For example, location information may be used in a relevancy determination of an ad. As another example, location information may be used in an attribute (e.g., position) arbitration. Such location information may be associated with price information, such as a maximum price bid. Such location information may be associated with ad performance information. Ad performance information may be tracked on the basis of location information. The content of an ad creative, and/or of a landing page may be selected and/or modified using location information. Finally, tools, such as user interfaces, may be provided to allow a business to enter and/or modify location information, such as location information used for targeting and location-dependent price information. The location information used to target and/or score ads may be, include, or define an area. The area may be defined by at least one geographic reference point (e.g., defined by latitude and longitude coordinates) and perhaps additional information. Thus, the area may be a circle defined by a geographic reference point and a radius, an ellipse defined by two geographic reference points and a distance sum, or a polygon defined by three or more geographic reference points, for example. | 1. A method for determining a relevancy of an ad to a request, the method comprising: a) accepting geolocation information associated with the request; b) comparing the accepted geolocation information associated with the request with geolocation targeting information associated with the ad to generate a comparison; and c) determining the relevancy of the ad using at least the comparison, wherein the geolocation targeting information associated with the ad is defined by at least one geographic reference point. 2. The method of claim 1 wherein the request further includes search terms, and wherein the act of determining the relevancy of the ad further uses a comparison of keyword targeting associated with the ad and the search terms. 3. The method of claim 1 wherein the request further includes document relevance information, and wherein the act of determining the relevancy of the ad further uses a comparison of ad relevance information and the document relevance information. 4. The method of claim 1 wherein the geolocation targeting information corresponds to a circular area having a radius about a specified geographic reference point. 5. The method of claim 1 wherein the geolocation targeting information corresponds to an area defined by at least three geographic reference points. 6. The method of claim 5 wherein the area defined by at least three geographic reference points is a polygon. 7. A method for determining a score of an ad, the method comprising: a) accepting geolocation information associated with a request; b) determining whether the ad has geolocation price information corresponding to the geolocation information accepted; and c) if it is determined that the ad has geolocation price information corresponding to the geolocation information accepted, then determining the score using at least the geolocation price information, wherein the geolocation price information associated with the ad corresponds to an area defined by at least one geographic reference point. 8. The method of claim 7 wherein the area includes a circular area having a radius about a specified geographic reference point. 9. The method of claim 7 wherein the area includes an area defined by at least three geographic reference points. 10. The method of claim 9 wherein the area defined by at least three geographic reference points is a polygon. 11. A method for determining a score of an ad with respect to a request, the method comprising: a) accepting geolocation information associated with the request; b) comparing the accepted geolocation information associated with the request with geolocation targeting information associated with the ad to generate a comparison; and c) determining the score of the ad using at least the comparison, wherein the geolocation information is a zip code included in the request. 12. The method of claim 11 wherein the request is a search query. 13. A method for determining a score of an ad with respect to a request, the method comprising: a) accepting geolocation information associated with the request; b) comparing the accepted geolocation information associated with the request with geolocation targeting information associated with the ad to generate a comparison; and c) determining the score of the ad using at least the comparison, wherein the geolocation information is at least one of a city name, a state name, a region name, and a country name, included in the request. 14. The method of claim 13 wherein the request is a search query. 15. Apparatus for determining a relevancy of an ad to a request, the apparatus comprising: a) means for accepting geolocation information associated with the request; b) means for comparing the accepted geolocation information associated with the request with geolocation targeting information associated with the ad to generate a comparison; and c) means for determining the relevancy of the ad using at least the comparison, wherein the geolocation targeting information associated with the ad is defined by at least one geographic reference point. 16. The apparatus of claim 15 wherein the request further includes search terms, and wherein the means for determining the relevancy of the ad further use a comparison of keyword targeting associated with the ad and the search terms. 17. The apparatus of claim 15 wherein the request further includes document relevance information, and wherein the means for determining the relevancy of the ad further use a comparison of ad relevance information and the document relevance information. 18. The apparatus of claim 15 wherein the geolocation targeting information corresponds to a circular area having a radius about a specified geographic reference point. 19. The apparatus of claim 15 wherein the geolocation targeting information corresponds to an area defined by at least three geographic reference points. 20. The apparatus of claim 19 wherein the area defined by at least three geographic reference points is a polygon. 21. Apparatus for determining a score of an ad, the apparatus comprising: a) means for accepting geolocation information associated with a request; b) means for determining whether the ad has geolocation price information corresponding to the geolocation information accepted; and c) means for determining the score using at least the geolocation price information if it is determined that the ad has geolocation price information corresponding to the geolocation information accepted, wherein the geolocation price information associated with the ad corresponds to an area defined by at least one geographic reference point. 22. The apparatus of claim 21 wherein the area includes a circular area having a radius about a specified geographic reference point. 23. The apparatus of claim 21 wherein the area includes an area defined by at least three geographic reference points. 24. The apparatus of claim 23 wherein the area defined by at least three geographic reference points is a polygon. 25. Apparatus for determining a score of an ad with respect to a request, the apparatus comprising: a) means for accepting geolocation information associated with the request; b) means for comparing the accepted geolocation information associated with the request with geolocation targeting information associated with the ad to generate a comparison; and c) means for determining the score of the ad using at least the comparison, wherein the geolocation information is a zip code included in the request. 26. The apparatus of claim 25 wherein the request is a search query. 27. Apparatus for determining a score of an ad with respect to a request, the apparatus comprising: a) means for accepting geolocation information associated with the request; b) means for comparing the accepted geolocation information associated with the request with geolocation targeting information associated with the ad to generate a comparison; and c) means for determining the score of the ad using at least the comparison, wherein the geolocation information is at least one of a city name, a state name, a region name, and a country name, included in the request. 28. The apparatus of claim 27 wherein the request is a search query. | § 0. RELATED APPLICATIONS This application is a continuation-in-part of U.S. patent application Ser. No. 10/654,265, titled “DETERMINING AND/OR USING LOCATION INFORMATION IN AN AD SYSTEM,” filed on Sep. 3, 2003 and listing Leslie Yeh, Sridhar Ramaswamy and Zhe Qian as inventors. That application is incorporated herein by reference. § 1. BACKGROUND OF THE INVENTION § 1.1 Field of the Invention The present invention concerns advertising. In particular, the present invention concerns improving advertising using location information. §1.2 Related Art Advertising using traditional media, such as television, radio, newspapers and magazines, is well known. Unfortunately, even when armed with demographic studies and entirely reasonable assumptions about the typical audience of various media outlets, advertisers recognize that much of their ad budget is simply wasted. Moreover, it is very difficult to identify and eliminate such waste. Recently, advertising over more interactive media has become popular. For example, as the number of people using the Internet has exploded, advertisers have come to appreciate media and services offered over the Internet as a potentially powerful way to advertise. Advertisers have developed several strategies in an attempt to maximize the value of such advertising. In one strategy, advertisers use popular presences or means for providing interactive media or services (referred to as “Websites” in the specification without loss of generality) as conduits to reach a large audience. Using this first approach, an advertiser may place ads on the home page of the New York Times Website, or the USA Today Website, for example. In another strategy, an advertiser may attempt to target its ads to more narrow niche audiences, thereby increasing the likelihood of a positive response by the audience. For example, an agency promoting tourism in the Costa Rican rainforest might place ads on the ecotourism-travel subdirectory of the Yahoo Website. An advertiser will normally determine such targeting manually. Regardless of the strategy, Website-based ads (also referred to as “Web ads”) are often presented to their advertising audience in the form of “banner ads”—i.e., a rectangular box that includes graphic components. When a member of the advertising audience (referred to as a “viewer” or “user” in the Specification without loss of generality) selects one of these banner ads by clicking on it, embedded hypertext links typically direct the viewer to the advertiser's Website. This process, wherein the viewer selects an ad, is commonly referred to as a “click-through” (“Click-through” is intended to cover any user selection.). The ratio of the number of click-throughs to the number of impressions of the ad (i.e., the number of times an ad is displayed or otherwise rendered) is commonly referred to as the “click-through rate” or “CTR” of the ad. A “conversion” is said to occur when a user consummates a transaction related to a previously served ad. What constitutes a conversion may vary from case to case and can be determined in a variety of ways. For example, it may be the case that a conversion occurs when a user clicks on an ad, is referred to the advertiser's Web page, and consummates a purchase there before leaving that Web page. Alternatively, a conversion may be defined as a user being shown an ad, and making a purchase on the advertiser's Web page within a predetermined time (e.g., seven days). In yet another alternative, a conversion may be defined by an advertiser to be any measurable/observable user action such as, for example, downloading a white paper, navigating to at least a given depth of a Website, viewing at least a certain number of Web pages, spending at least a predetermined amount of time on a Website or Web page, etc. Often, if user actions don't indicate a consummated purchase, they may indicate a sales lead, although user actions constituting a conversion are not limited to this. Indeed, many other definitions of what constitutes a conversion are possible. The ratio of the number of conversions to the number of impressions of the ad (i.e., the number of times an ad is displayed or otherwise rendered) is commonly referred to as the conversion rate. If a conversion is defined to be able to occur within a predetermined time since the serving of an ad, one possible definition of the conversion rate might only consider ads that have been served more than the predetermined time in the past. The hosts of Websites on which the ads are presented (referred to as “Website hosts” or “ad consumers”) have the challenge of maximizing ad revenue without impairing their users' experience. Some Website hosts have chosen to place advertising revenues over the interests of users. One such Website is “Overture.com,” which hosts a so-called “search engine” service returning advertisements masquerading as “search results” in response to user queries. The Overture.com Website permits advertisers to pay to position an ad for their Website (or a target Website) higher up on the list of purported search results. If such schemes where the advertiser only pays if a user clicks on the ad (i.e., cost-per-click) are implemented, the advertiser lacks incentive to target their ads effectively, since a poorly targeted ad will not be clicked and therefore will not require payment. Consequently, high cost-per-click ads show up near or at the top, but do not necessarily translate into real revenue for the ad publisher because viewers don't click on them. Furthermore, ads that viewers would click on are further down the list, or not on the list at all, and so relevancy of ads is compromised. Search engines, such as Google for example, have enabled advertisers to target their ads so that they will be rendered in conjunction with a search results page responsive to a query that is relevant, presumably, to the ad. Although search result pages afford advertisers a great opportunity to target their ads to a more receptive audience, search result pages are merely a fraction of page views of the World Wide Web. Some online advertising systems may use ad relevance information and document content relevance information (e.g., concepts or topics, feature vectors, etc.) to “match” ads to (and/or to score ads with respect to) a document including content, such as a Web page for example. The foregoing ad serving systems can be thought of as keyword-targeted systems (where ads are targeted using terms found in a search query) and content-targeted systems (where ads are targeted using content of a document). Although keyword-targeted and content-targeted ad systems have improved the usefulness of ads, and consequently their performance (e.g., in terms of click-through rate, conversion rate, etc.), there is still plenty of room for improvement. Such improvement can be expected with better targeting. The Google keyword ad server allows advertisers to specify (e.g., for purposes of targeting) one or more countries in which their ad may be served. This permits ads to be served to particular users who presumably speak and understand a particular language. Unfortunately, however, many businesses have only a regional or local reach. For example, a restaurant may want to target ads only to potential customers within a 30 minute drive. A dry cleaner may want to target ads only to potential customers in the same town, and perhaps a few neighboring towns. As another example, a regional chain of drug stores may only want to target ads to potential customers living within their region. Even if such businesses have ads that are relevant to a search query or a Web page, if the end user viewing a search results Web page or the content of a Web page is outside the geographic reach of their business, the ads will not be very useful and will not perform well. If ads only generate revenue (e.g., for a content owner or ad system) when they perform well (e.g., if they are selected), such ads will generate little, if any, revenue. Such businesses often advertise in local papers and the telephone book yellow pages. While such conduits for advertisements are useful, they are limited. Such businesses may also advertise on local Websites, but this requires the business to find local Websites, and to track and manage advertising on each of the Websites. In view of the foregoing, there is a need for improving the usefulness, and consequently the performance, of advertisements. In particular, there is a need to allow businesses to better target their ads to a responsive audience. § 2. SUMMARY OF THE INVENTION The present invention improves the usefulness, and consequently the performance, of advertisements. The present invention allows businesses to better target their ads to a responsive audience. The present invention may do so by determining and using location information, such as country, region, metro area, city or town, postal zip code, telephone area code, etc. The present invention may also use location information when determining a relevancy score of an ad. The present invention may also use location information in an attribute (e.g., position) arbitration. Such location information may be associated with price information, such as a maximum price bid. Such location information may be associated with ad performance information. The present invention may also track ad performance information on the basis of location information. The present invention may select or modify the content of an ad creative, and/or of a landing page using location information. For example, location information may be inserted into an ad creative. As another example, different landing pages with different content can be used for different locations. The present invention may also provide tools, such as user interfaces, to allow a business to enter and/or modify location information, such as location information used for targeting and location-dependent price information. § 3. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a high-level diagram showing parties or entities that can interact with an advertising system. FIG. 2 is a diagram illustrating an environment in which, or with which, the present invention may operate. FIG. 3 is a bubble diagram illustrating various operations that may be performed, and various information that may be used and/or generated, by the present invention. FIG. 4 illustrates exemplary request information that is consistent with the present invention. FIG. 5 illustrates exemplary ad information that is consistent with the present invention. FIG. 6 is a flow diagram of an exemplary method for performing an ad selection operation in a manner consistent with the present invention. FIG. 7 is a flow diagram of an exemplary method for performing a scoring operation in a manner consistent with the present invention. FIG. 8 is a flow diagram of an exemplary method for performing an ad modification operation in a manner consistent with the present invention. FIG. 9 is a flow diagram of an exemplary method of performing user behavior feedback operations in a manner consistent with the present invention. FIG. 10 is a flow diagram of an exemplary method for performing ad information entry and/or management operations in a manner consistent with the present invention. FIG. 11 is a block diagram of an exemplary apparatus that may perform various operations in a manner consistent with the present invention. § 4. DETAILED DESCRIPTION The present invention may involve novel methods, apparatus, message formats, and/or data structures for obtaining and using geolocation information in an ad system. The following description is presented to enable one skilled in the art to make and use the invention, and is provided in the context of particular applications and their requirements. Various modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles set forth below may be applied to other embodiments and applications. Thus, the present invention is not intended to be limited to the embodiments shown and the inventors regard their invention as any patentable subject matter described. In the following, environments in which, or with which, the present invention may operate are described in § 4.1. Then, exemplary embodiments of the present invention are described in § 4.2. Finally, some conclusions regarding the present invention are set forth in § 4.3. § 4.1 Environments in which, or with which, the Present Invention may Operate § 4.1.1 Exemplary Advertising Environment FIG. 1 is a high level diagram of an advertising environment. The environment may include an ad entry, maintenance and delivery system (simply referred to as an ad server) 120. Advertisers 110 may directly, or indirectly, enter, maintain, and track ad information in the system 120. The ads may be in the form of graphical ads such as so-called banner ads, text only ads, image ads, audio ads, video ads, ads combining one of more of any of such components, etc. The ads may also include embedded information, such as a link, and/or machine executable instructions. Ad consumers 130 may submit requests for ads to, accept ads responsive to their request from, and provide usage information to, the system 120. An entity other than an ad consumer 130 may initiate a request for ads. Although not shown, other entities may provide usage information (e.g., whether or not a conversion or click-through related to the ad occurred) to the system 120. This usage information may include measured or observed user behavior related to ads that have been served. The ad server 120 may be similar to the one described in FIG. 2 of U.S. patent application Ser. No. 10/375,900 (incorporated herein by reference), entitled “SERVING ADVERTISEMENTS BASED ON CONTENT,” filed on Feb. 26, 2003 and listing Darrell Anderson, Paul Bucheit, Alex Carobus, Claire Cui, Jeffrey A. Dean, Georges R. Harik, Deepak Jindal, and Narayanan Shivakumar as inventors. An advertising program may include information concerning accounts, campaigns, creatives, targeting, etc. The term “account” relates to information for a given advertiser (e.g., a unique e-mail address, a password, billing information, etc.). A “campaign” or “ad campaign” refers to one or more groups of one or more advertisements, and may include a start date, an end date, budget information, geo-targeting information, syndication information, etc. For example, Honda may have one advertising campaign for its automotive line, and a separate advertising campaign for its motorcycle line. The campaign for its automotive line have one or more ad groups, each containing one or more ads. Each ad group may include targeting information (e.g., a set of keywords, a set of one or more topics, etc.), and price information (e.g., maximum cost (cost per click-though, cost per conversion, etc.)). Alternatively, or in addition, each ad group may include an average cost (e.g., average cost per click-through, average cost per conversion, etc.). Therefore, a single maximum cost and/or a single average cost may be associated with one or more keywords, and/or topics. As stated, each ad group may have one or more ads or “creatives” (That is, ad content that is ultimately rendered to an end user.). Each ad may also include a link to a URL (e.g., a landing Web page, such as the home page of an advertiser, or a Web page associated with a particular product or server). Consistent with the present invention, the ad information may include geolocation targeting information, geolocation performance information, and/or geolocation price information Naturally, the ad information may include more or less information, and may be organized in a number of different ways. FIG. 2 illustrates an environment 200 in which the present invention may be used. A user device (also referred to as a “client” or “client device”) 250 may include a browser facility (such as the Explorer browser from Microsoft, the Opera Web Browser from Opera Software of Norway, the Navigator browser from AOL/Time Warner, etc.), an e-mail facility (e.g., Outlook from Microsoft), etc. A search engine 220 may permit user devices 250 to search collections of documents (e.g., Web pages). A content server 210 may permit user devices 250 to access documents. An e-mail server (such as Hotmail from Microsoft Network, Yahoo Mail, etc.) 240 may be used to provide e-mail functionality to user devices 250. An ad server 210 may be used to serve ads to user devices 250. The ads may be served in association with search results provided by the search engine 220. However, content-relevant ads may be served in association with content provided by the content server 230, and/or e-mail supported by the e-mail server 240 and/or user device e-mail facilities. As discussed in U.S. patent application Ser. No. 10/375,900 (introduced above), ads may be targeted to documents served by content servers. Thus, one example of an ad consumer 130 is a general content server 230 that receives requests for documents (e.g., articles, discussion threads, music, video, graphics, search results, Web page listings, etc.), and retrieves the requested document in response to, or otherwise services, the request. The content server may submit a request for ads to the ad server 120/210. Such an ad request may include a number of ads desired. The ad request may also include document request information. This information may include the document itself (e.g., page), a category or topic corresponding to the content of the document or the document request (e.g., arts, business, computers, arts-movies, arts-music, etc.), part or all of the document request, content age, content type (e.g., text, graphics, video, audio, mixed media, etc.), geo-location information, document information, etc. Consistent with the present invention, the request may also include geolocation information, such as location information about an end user that submitted a search query. The content server 230 may combine the requested document with one or more of the advertisements provided by the ad server 120/210. This combined information including the document content and advertisement(s) is then forwarded towards the end user device 250 that requested the document, for presentation to the user. Finally, the content server 230 may transmit information about the ads and how, when, and/or where (such as geolocation information) the ads are to be rendered (e.g., position, click-through or not, impression time, impression date, size, conversion or not, etc.) back to the ad server 120/210. Alternatively, or in addition, such information may be provided back to the ad server 120/210 by some other means. Consistent with the present invention, the ad server 120/210 may store ad performance information on the basis of geolocation information. Another example of an ad consumer 130 is the search engine 220. A search engine 220 may receive queries for search results. In response, the search engine may retrieve relevant search results (e.g., from an index of Web pages). An exemplary search engine is described in the article S. Brin and L. Page, “The Anatomy of a Large-Scale Hypertextual Search Engine,” Seventh International World Wide Web Conference, Brisbane, Australia and in U.S. Pat. No. 6,285,999 (both incorporated herein by reference). Such search results may include, for example, lists of Web page titles, snippets of text extracted from those Web pages, and hypertext links to those Web pages, and may be grouped into a predetermined number of (e.g., ten) search results. The search engine 220 may submit a request for ads to the ad server 120/210. The request may include a number of ads desired. This number may depend on the search results, the amount of screen or page space occupied by the search results, the size and shape of the ads, etc. In one embodiment, the number of desired ads will be from one to ten, and preferably from three to five. The request for ads may also include the query (as entered or parsed), information based on the query (such as geolocation information, whether the query came from an affiliate and an identifier of such an affiliate), and/or information associated with, or based on, the search results. Such information may include, for example, identifiers related to the search results (e.g., document identifiers or “docIDs”), scores related to the search results (e.g., information retrieval (“IR”) scores such as dot products of feature vectors corresponding to a query and a document, Page Rank scores, and/or combinations of IR scores and Page Rank scores), snippets of text extracted from identified documents (e.g., Web pages), full text of identified documents, topics of identified documents, feature vectors of identified documents, etc. Consistent with the present invention, the request may also include geolocation information, such as location information about an end user that submitted a search query. The search engine 220 may combine the search results with one or more of the advertisements provided by the ad server 120/210. This combined information including the search results and advertisement(s) is then forwarded towards the user that submitted the search, for presentation to the user. Preferably, the search results are maintained as distinct from the ads, so as not to confuse the user between paid advertisements and presumably neutral search results. Finally, the search engine 220 may transmit information about the ad and when, where (e.g., geolocation), and/or how the ad was to be rendered (e.g., position, click-through or not, impression time, impression date, size, conversion or not, etc.) back to the ad server 120/210. Alternatively, or in addition, such information may be provided back to the ad server 120/210 by some other means. Consistent with the present invention, the ad server 120/210 may store ad performance information on the basis of geolocation information. Finally, the e-mail server 240 may be thought of, generally, as a content server in which a document served is simply an e-mail. Further, e-mail applications (such as Microsoft Outlook for example) may be used to send and/or receive e-mail. Therefore, an e-mail server 240 or application may be thought of as an ad consumer 130. Thus, e-mails may be thought of as documents, and targeted ads may be served in association with such documents. For example, one or more ads may be served in, under over, or otherwise in association with an e-mail. Although the foregoing examples described servers as (i) requesting ads, and (ii) combining them with content, one or both of these operations may be performed by a client device (such as an end user computer for example). § 4.1.2 Definitions “Geolocation information” may include information specifying one or more of one or more countries, one or more (inter-country) regions, one or more states, one or more metro areas, one or more cities, one or more towns, one or more boroughs, one or more areas with common zip codes, one or more areas with common telephone area codes, one or more areas served by common cable head end stations, one or more areas served by common network access points or nodes, one or more geographic areas defined by some other means, etc. It may include latitude and/or longitude, or a range thereof. Thus, for example, it may be or include an area defined by a geographic reference point and perhaps some additional information, such as a circular area of a defined radius about a point defined by latitude and longitude coordinates for example. As another example, it may be an area defined by three or more geographic reference points, such as a triangle, rectangle, pentagon, or some other polygon defined by a number of geographic reference points for example. It may include information, such as an IP address, from which a user location can be estimated. Online ads, such as those used in the exemplary systems described above with reference to FIGS. 1 and 2, or any other system, may have various intrinsic features. Such features may be specified by an application and/or an advertiser. These features are referred to as “ad features” below. For example, in the case of a text ad, ad features may include a title line, ad text, and an embedded link. In the case of an image ad, ad features may include images, executable code, and an embedded link. Depending on the type of online ad, ad features may include one or more of the following: text, a link, an audio file, a video file, an image file, executable code, embedded information, etc. When an online ad is served, one or more parameters may be used to describe how, when, and/or where the ad was served. These parameters are referred to as “serving parameters” below. Serving parameters may include, for example, one or more of the following: features of (including information on) a page on which the ad was served, a search query or search results associated with the serving of the ad, a user characteristic (e.g., their geolocation, the language used by the user, the type of browser used, previous page views, previous behavior), a host or affiliate site (e.g., America Online, Google, Yahoo) that initiated the request, an absolute position of the ad on the page on which it was served, a position (spatial or temporal) of the ad relative to other ads served, an absolute size of the ad, a size of the ad relative to other ads, a color of the ad, a number of other ads served, types of other ads served, time of day served, time of week served, time of year served, etc. Naturally, there are other serving parameters that may be used in the context of the invention. Although serving parameters may be extrinsic to ad features, they may be associated with an ad as serving conditions or constraints. When used as serving conditions or constraints, such serving parameters are referred to simply as “serving constraints” (or “targeting criteria”). For example, in some systems, an advertiser may be able to target the serving of its ad by specifying that it is only to be served on weekdays, no lower than a certain position, only to users in a certain geolocation, etc. As another example, in some systems, an advertiser may specify that its ad is to be served only if a page or search query includes certain keywords or phrases. As yet another example, in some systems, an advertiser may specify that its ad is to be served only if a document being served includes certain topics or concepts, or falls under a particular cluster or clusters, or some other classification or classifications. “Ad information” may include any combination of ad features, ad serving constraints, information derivable from ad features or ad serving constraints (referred to as “ad derived information”), and/or information related to the ad (referred to as “ad related information”), as well as an extension of such information (e.g., information derived from ad related information). A “document” is to be broadly interpreted to include any machine-readable and machine-storable work product. A document may be a file, a combination of files, one or more files with embedded links to other files, etc. The files may be of any type, such as text, audio, image, video, etc. Parts of a document to be rendered to an end user can be thought of as “content” of the document. A document may include “structured data” containing both content (words, pictures, etc.) and some indication of the meaning of that content (for example, e-mail fields and associated data, HTML tags and associated data, etc.) Ad spots in the document may be defined by embedded information or instructions. In the context of the Internet, a common document is a Web page. Web pages often include content and may include embedded information (such as meta information, hyperlinks, etc.) and/or embedded instructions (such as Javascript, etc.). In many cases, a document has a unique, addressable, storage location and can therefore be uniquely identified by this addressable location. A universal resource locator (URL) is a unique address used to access information on the Internet. “Document information” may include any information included in the document, information derivable from information included in the document (referred to as “document derived information”), and/or information related to the document (referred to as “document related information”), as well as an extensions of such information (e.g., information derived from related information). An example of document derived information is a classification based on textual content of a document. Examples of document related information include document information from other documents with links to the instant document, as well as document information from other documents to which the instant document links. Content from a document may be rendered on a “content rendering application or device”. Examples of content rendering applications include an Internet browser (e.g., Explorer or Netscape), a media player (e.g., an MP3 player, a Realnetworks streaming audio file player, etc.), a viewer (e.g., an Abobe Acrobat pdf reader), etc. A “content owner” is a person or entity that has some property right in the content of a document. A content owner may be an author of the content. In addition, or alternatively, a content owner may have rights to reproduce the content, rights to prepare derivative works of the content, rights to display or perform the content publicly, and/or other proscribed rights in the content. Although a content server might be a content owner in the content of the documents it serves, this is not necessary. “User information” may include user behavior information and/or user profile information. It may also include a user's geolocation, or an estimation of the user's geolocation. “E-mail information” may include any information included in an e-mail (also referred to as “internal e-mail information”), information derivable from information included in the e-mail and/or information related to the e-mail, as well as extensions of such information (e.g., information derived from related information). An example of information derived from e-mail information is information extracted or otherwise derived from search results returned in response to a search query composed of terms extracted from an e-mail subject line. Examples of information related to e-mail information include e-mail information about one or more other e-mails sent by the same sender of a given e-mail, or user information about an e-mail recipient. Information derived from or related to e-mail information may be referred to as “external e-mail information.” Various exemplary embodiments of the present invention are now described in § 4.2. § 4.2 Exemplary Embodiments FIG. 3 is a bubble diagram illustrating various operations that may be performed by the present invention, and various information that may be used and/or generated by the present invention. An ad selection operation 310 may be used to generate a set of ads 340 using ad information 330 and request information 320. In an exemplary embodiment of the present invention, the set of ads 340 may include ads relevant to the request information 320. For example, if the request information 320 is associated with a search query, the ads 340 may be relevant to terms of the search query. Alternatively, if the request information 320 is associated with a document to be served, the ads 340 may be relevant to content of the document. In any event, the request information 320 may include geolocation information. For example, the request information 320 may include geolocation of an end user that submitted a search query or document request (or some other entity, such as a cable head end, a network access point, etc., associated with the request), or information from which such geolocation information can be derived. Exemplary data structures that may be used to store request information 320 and ad information 330 are described in § 4.2.1 below with reference to FIGS. 4 and 5, respectively. Exemplary methods that may be used to perform the ad selection operation 310 are described in § 4.2.2 below with reference to FIG. 6. Still referring to FIG. 3, a scoring operation 350 may be used to generate a set 360 of ads and associated scores using the first set 340 of ads and ad information 330. The scoring operation 350 may consider geolocation information, such as geolocation performance information, and/or geolocation price information for example, of the ads. Exemplary methods that may be used to perform the scoring operation 350 are described in § 4.2.2 below with reference to FIG. 7. Ad modification operations 370 may be used to generate a set 380 of ads with location specific creative content, and/or a location specific landing page from the set 360 of ads. Although not shown, the ad modification operations 370 may use geolocation information. Exemplary methods that may be used to perform the ad modification operations 370 are described in § 4.2.2 below with reference to FIG. 8. The ad information 330 may include geolocation-based performance information. Such information may be provided, and/or tracked by user behavior feedback operations 390. Exemplary methods that may be used to perform the user behavior feedback operations are described in § 4.2.2 below with reference to FIG. 9. Finally, the ad information 330 may include geolocation targeting, and/or geolocation price information. This information may be entered and/or modified by advertisers, or their representatives via ad information entry and/or management operations 335. Exemplary methods that may be used to perform these operations 335 are described in § 4.2.2 below with reference to FIG. 10. The present invention need not provide, and/or use all of the operations and information described with reference to FIG. 3. The present invention need not perform the operations in the order shown. Finally, the present invention may combine, or separate functionality described with respect to the various operations. For example, the selection and scoring operations 310 and 350 may be combined into a single operation. § 4.2.1 Exemplary Data Structures FIG. 4 illustrates exemplary ad request information 320′ that is consistent with the present invention. The ad request information 320′ may include information such as that described in § 4.1.1 above. Further, the ad request information may include end user (or some other entity, simply referred to as “end user” in the specification) geolocation information, or information from which end user geolocation can be derived or estimated. For example, the end user geolocation information may include one or more of a country, a region (e.g., pacific coast, north-east, mid-Atlantic, south-west, etc.), a state, a metro area (e.g., San Francisco Bay Area, Metro District of Columbia Area, etc.), a city, a town, a postal zip code, a telephone area code, etc. The geolocation information may be encoded in various ways. For example, a country identifier may be a two character code such as those determined by the International Organization for Standardization (“ISO”). The region identifier may be a six character code such as those determined by UTF8. Thus, the country and region can be encoded using the ISO 3166-2/1999 standard which is a two letter country code followed by a “-” and 1-3 alphanumeric characters. The ISO 3166-2/1999 standard code can be mapped to a numerical identifier (e.g., in the range of 20001-30000). New regions can be assigned a numerical identifier appended to the end. In one embodiment of the present invention, more than 200 countries and 1300 regions are uniquely identified. The metro area identifier may be based on the DMA standard. In one embodiment, metro areas can cross state lines. Accordingly, in such an embodiment, a metro area is not necessarily “contained” within a state. Since the same city or town name can be used for different cities or towns in different states, such information should be used in combination with state information to avoid ambiguity. Postal zip codes can be encoded as a 5-digit integer, or extended with 4 or more digits. Telephone area codes may be encoded as a three-digit integer. Other ways of encoding geolocation information are possible. The present invention may be used to derive or estimate geolocation information from other information. For example, the present invention may use known techniques (such as that used by the “NetAcuity” product from Digital Envoy of Norcross, Ga.) to map Internet protocol (“IP”) address and/or domain information to geolocation information. As another example, Internet service providers may have many dial-in access servers, each associated with a telephone area code. As yet another example, an end user's location might be inferred from a regional term (e.g., hoagie, hero, grinder, sub) entered by the user. If multiple factors are used to infer geolocation, but lead to inconsistent locations, each without a desired level of confidence, a more general, consistent location, can be used. Alternatively, the present invention may simply accept previously derived or provided geolocation information. For example, the end user, or a client device used by the end user, may have voluntarily provided geolocation information. As another example, the geolocation information may have been derived and provided by a third party. FIG. 5 illustrates exemplary ad information 330′ that is consistent with the present invention. The ad information 330′ may include information such as that described in § 4.1.1 above. For example, the ad information 330′ may include a unique ad identifier, ad creative content (or a pointer to such creative content), and/or a landing page link, etc. Further, the exemplary ad information 330′ may include at least one of geolocation targeting information and geolocation price information. Geolocation performance information (not shown) may be tracked and associated with the ad. Geolocation targeting information may include one or more countries, one or more regions, one or more states, one or more metro areas, one or more cities, one or more towns, one or more postal zip codes, and/or one or more telephone area codes, etc. Thus, for example, a business selling irrigation systems can target its ads to the states California, Nevada, Arizona and New Mexico, while a business selling snow blowers can target its ads to states, such as Maine and Minnesota for example, with relatively significant snowfall. A dry cleaner can target its ads to the town in which it is located, as well as neighboring towns, and/or various postal zip codes, and/or various telephone area codes. A professional sports team can target ads for tickets and/or merchandise to a metro area. A national shipping company can target its ads to a country. Geolocation targeting information may also be or include an area (or areas) defined by at least one geographic reference point and perhaps some additional information, such as a circular area of a defined radius about a point defined by latitude and longitude coordinates for example, an elliptical area defined by two geographic reference points and a defined distance sum, etc. As another example, geolocation targeting information may be or include an area (or areas) defined by three or more geographic reference points, such as a triangle, rectangle, pentagon, or some other polygon defined by a number of reference points for example. Geolocation price information may include price information for each of one or more countries, one or more regions, one or more states, one or more metro areas, one or more cities, one or more towns, one or more postal zip codes, and/or one or more telephone area codes, etc. Geolocation price information may also include price information for an area (or areas) defined using at least one geographic reference point and perhaps some additional information. The price information should correspond to the geolocation targeting information. In one embodiment of the present invention, geolocation targeting information can be inferred from geolocation price information. For example, if an advertiser submits a maximum bid per impression of $1.50 for the geolocation DC metro, it may be assumed that the advertiser wants to target its ads to end users in the DC metro area. Similarly, if the advertiser submits a bid per impression of $0.00 for a given state, it may be assumed that the advertiser wants to avoid serving its ads to end users in the state. For example, if a car insurance provider is licensed to provide insurance in all states except for New Jersey, and is not as interested in writing less profitable policies in Florida, it can provide the following geolocation price information: United States: $1.00/impression; New Jersey: $0.00/impression; and Florida: $0.15/impression. As will be described in more detail with reference to FIG. 7 below, a scoring operation 350 may weigh more specific geolocation price information more than less specific geolocation price information. § 4.2.2 Exemplary Methods FIG. 6 is a flow diagram of an exemplary method 310′ for performing a ad selection operation 310 in a manner consistent with the present invention. Request information and ad information is accepted. (Block 610) The request information may include, among other things, end user geolocation information. The advertising information may include, among other things, geolocation targeting information. As indicated by loop 620-640, an act is performed for each of one or more ads. More specifically, a relevancy measure of the ad is determined using at least geolocation information associated with the request information and geolocation targeting information associated with the ad. (Block 630) After each of the one or more ads have been processed, the method 310′ is left. (Node 650) The relevancy of the ad may be determined using keyword targeting information associated with the ad, ad relevance information associated with the ad, etc. In any event, the relevancy of the ad may be determined using, at least, geolocation information of the request and the ad. The more specific the geolocation information that matches, the more relevant, at least in terms of location, the ad is. Thus, for example, if an end user submitted a search query from San Diego, assuming all other relevancy factors are equal, an ad with geotargeting for San Diego may be more relevant than an ad with geotargeting for California, which may be more relevant for an ad with geotargeting for the West Coast, which may be more relevant for an ad with geotargeting for the United States. Naturally, geolocation targeting may be just one of a number of relevancy factors. For example, ad relevancy may also consider (a) a comparison of ad relevancy information to the content of a document requested, (b) ad keyword targeting with respect to terms of a search query, (c) user demographic information, (d) user behavior information, (e) time/date/season targeting information, etc. FIG. 7 is a flow diagram of an exemplary method 350′ for performing a scoring operation 350 in a manner consistent with the present invention. The second score may be used to determine a relative presentation attribute (e.g., size, position, color, volume, etc.) of the ad. Ad information of candidate ads is accepted. (Block 710) As indicated by loop 720-740, an act is performed for each of one or more ads. More specifically, an ad score is determined using at least one of price information, geolocation price information (if available), performance information, and geolocation performance information (if available). (Block 730) Once all of the candidate ads are processed, the method 350′ is left. (Node 750) There are a number of ways to determine an ad score consistent with block 730. A few exemplary ways are described below. If an ad system wants to maximize revenue, it may determine a score by multiplying a price per performance value by the performance of the ad. For example, it may determine cost per click*click-through rate, or cost per conversion*conversion rate. Prices may be discounted or adjusted. The present invention can advantageously use geolocation information, if available, to improve a revenue estimate. For example, suppose the end user to whom the ad will be directed is located in San Diego. Suppose further that the following otherwise equally relevant ads have the associated information shown: Ad A: max cost per click=$0.25; max cost per click=$1.00 in San Diego; CTR=0.02 in United States; CTR=0.04 in California; CTR=0.20 in San Diego. Ad B: max cost per click=$0.50; max cost per click=$2.00 in Florida; CTR=0.07 in United States; CTR=0.02 in California; CTR=0.02 in San Diego. Without geolocation scoring, a simple product score for ad A would be 0.0050 (=0.25*0.02), while that for ad B would be 0.0350 (=0.50*0.07). With geolocation scoring, a simple product score for ad A would be 0.20 (=1.00*0.20), while that for ad B would be 0.01 (=0.50*0.02). Thus, without geolocation information, ad B would score higher than ad A, but with geolocation information ad A would score higher than ad B. For example, ad A may be for a restaurant in San Diego, while ad B might be for a pool construction company with a large presence in Florida. By using geolocation information, the present invention may advantageously serve ad A with some preference over ad B since it may normally be more useful for an end user in San Diego. In one embodiment of the present invention, if more specific geolocation price information is not available, more general geolocation price information may be used in the determination of a score. Similarly, if more specific geolocation performance information is not available, more general geolocation performance information may be used. Thus, for example, an ad with only geolocation price and performance information for California may compete with an ad with geolocation price and performance information for Sacramento when serving an ad request with Sacramento geolocation information. FIG. 8 is a flow diagram of an exemplary method 370′ for performing an ad modification operation 370 in a manner consistent with the present invention. Ad information and/or request geolocation information is accepted. (Block 810) Request geolocation information may be provided in the creative content of the ad, and/or the ad may be provided with geolocation-dependent content (e.g., one of a number of candidate ad marketing messages may be selected using geolocation information). (Block 820) Alternatively, or in addition, request geolocation information may be provided in the content of a landing page, and/or geolocation-dependent content may be provided in the ad landing page (e.g., one of a number of candidate landing pages may be selected using geolocation information). (Block 830) Referring back to block 820, the content of an ad creative may be modified by modifying text or by selecting one of a number of candidate texts. For example, assume that an ad request indicated that the end user is in Tampa Fla., and assume that an ad for a Honda Car Dealer was targeted to Tampa Fla. The normal ad creative may read, “Attention Car Buyers . . . Best Prices on Accords . . . Hundreds in Stock.” The modified ad creative may read, “Attention Tampa Car Buyers . . . Best Prices on Accords in Tampa.” The geolocation information may simply be added to, or replace a portion of, the ad creative. The geolocation information may be used to select a number of candidate ad creatives. Referring back to block 830, the one of a plurality of ad landing pages may be selected based on geolocation information. For example, if the geolocation information of the request indicates that the end user is local, a retailer may have a landing page emphasizing the message “Visit our Local Showroom to see the latest merchandize.” If, on the other hand, the geolocation information of the request indicates that the end user is remote, a retailer may have a landing page emphasizing “Best Prices on the Web. Free Shipping through the end of July.” Alternative or in addition to generating creative content targeted towards a specific location (e.g., “Find this at Office Depot on San Antonio Road/El Camino”), advertisement attributes may be determined using location information. For example, pricing can be determined using “local” competition, local demographics (e.g. income by zip code), or local buying habits. Prices and/or products may be specific to a location (e.g. a query for “NYC” yields an ad “Fly to JFK from SFO for $199”). Thus, by using geolocation information, the present invention can be used to adapt a marketing message to the location of an end user to perceive the ad. FIG. 9 is a flow diagram of an exemplary method 390′ for performing user behavior feedback operation 390 in a manner consistent with the present invention. Recall from scoring operation 350 that geolocation specific performance information may be used in determining a score for an ad. The method 390′ of FIG. 9 is one way to track such information. Each time an ad is served, this event may be identified by a unique process identifier (e.g., ad server IP address, a date and a time of day). The process identifier may be associated with any geolocation targeting information used when serving the ad, or geolocation information of the relevant request. The ad may be served with its process identifier. (Block 910) As indicated by event block 920, different branches of the method 390′ may be performed in response to different events. For example, if user behavior information is received, the received user behavior information is associated with the process identifier (and therefore the geolocation information, if any, used when originally serving the ad) (Block 930) before the method 390′ branches back to event block 920. If a condition for updating performance information is met (e.g., the receipt of performance information, the receipt of a certain amount of performance information, a time expiration since the last update, an absolute time/date, etc), the ad performance information is updated considering geolocation targeting information, or geolocation request information associated with the ad serving process (Block 940), before the method 390′ branches back to event block 920. Thus, the method 390′ can be used to track ad performance information accounting for geolocation information that may have been used when serving the ad. Various alternative ways of associating geolocation information with performance information are possible. FIG. 10 is a flow diagram of an exemplary method 335′ of performing ad information entry and/or management operations in a manner consistent with the present invention. Recall from FIG. 5 that ad information 330′ may include one or more of geolocation targeting information and geolocation price information. The method 330′ accepts authorized and/or authenticated user input. (Block 1010) As indicated by event block 1020, various branches of the method 335′ may be performed in response to various input types. If the user inputs geolocation price information, geolocation price information is added or updated. (Block 1030) Associated geolocation targeting information may also be populated or revised in accordance with the price information. (Block 1040) For example, if a user enters a maximum price per click of $0.80 for California, and if the ad does not include geolocation targeting for California, such information may be added. If the user later changes this maximum price per click for California to $0.00, the geolocation targeting for California may be turned off or removed. Referring back to block 1020, if the user inputs geolocation targeting information, the geolocation targeting information is added or updated. (Block 1050) Associated geolocation price information may be requested (Block 1060) but need not be provided. In one embodiment of the present invention, the advertiser user interface can be location specific. In one embodiment of the present invention, if an advertiser inputs geolocation targeting information, it may be advisable to have them remove location modifiers used in keyword targeting. In one embodiment of the present invention, advertisers may be limited in the number and/or combination of types of geolocation information entered. Other features of the advertiser user interface may be provided to make entering and/or managing advertising information more convenient. For example, if any advertiser has an existing campaign, but wants to add a geolocation targeted campaign, bulk importing support may be provided so that the advertiser does not need to re-enter common advertising information. Help features may be used to suggest additional geolocation information (more of the same type, more specific, more general, etc.) in response to entered geolocation information. For example, if the advertiser enters a postal zip code, they may be provided with one or more towns, regions, etc. § 4.2.3 Exemplary Apparatus FIG. 11 is high-level block diagram of a machine 1100 that may perform one or more of the operations discussed above. The machine 1100 basically includes one or more processors 1110, one or more input/output interface units 1130, one or more storage devices 1120, and one or more system buses and/or networks 1140 for facilitating the communication of information among the coupled elements. One or more input devices 1132 and one or more output devices 1134 may be coupled with the one or more input/output interfaces 1130. The one or more processors 1110 may execute machine-executable instructions (e.g., C or C++ running on the Solaris operating system available from Sun Microsystems Inc. of Palo Alto, Calif. or the Linux operating system widely available from a number of vendors such as Red Hat, Inc. of Durham, N.C.) to effect one or more aspects of the present invention. At least a portion of the machine executable instructions may be stored (temporarily or more permanently) on the one or more storage devices 1120 and/or may be received from an external source via one or more input interface units 1130. In one embodiment, the machine 1100 may be one or more conventional personal computers. In this case, the processing units 1110 may be one or more microprocessors. The bus 1140 may include a system bus. The storage devices 1120 may include system memory, such as read only memory (ROM) and/or random access memory (RAM). The storage devices 1120 may also include a hard disk drive for reading from and writing to a hard disk, a magnetic disk drive for reading from or writing to a (e.g., removable) magnetic disk, and an optical disk drive for reading from or writing to a removable (magneto-) optical disk such as a compact disk or other (magneto-) optical media. A user may enter commands and information into the personal computer through input devices 1132, such as a keyboard and pointing device (e.g., a mouse) for example. Other input devices such as a microphone, a joystick, a game pad, a satellite dish, a scanner, or the like, may also (or alternatively) be included. These and other input devices are often connected to the processing unit(s) 1110 through an appropriate interface 1130 coupled to the system bus 1140. The output devices 1134 may include a monitor or other type of display device, which may also be connected to the system bus 1140 via an appropriate interface. In addition to (or instead of) the monitor, the personal computer may include other (peripheral) output devices (not shown), such as speakers and printers for example. § 4.2.4 Alternatives Different geolocation information may have different scope, and some geolocation information may contain other geolocation information. Generally, for purposes of determining ad relevancy, a match of more specific geolocation information (e.g., town) may be weighted more heavily than a match of less specific geolocation information (e.g., country). Generally, for purposes of ad scoring, the most specific geolocation price and/or performance information that matches will be used. That is, if an ad has price and performance information for both San Diego and California, if the request geolocation information indicates an end user in San Diego, the San Diego price and performance information will be used. If on the other hand, the request geolocation information indicates an end user in Sacramento, the California price and performance information will be used. If the request geolocation information indicates an end user in Omaha, Nebraska, neither will be used. There are many different ways to score ads. Some examples include (a) using a distance between a presence of the advertiser and the end user, (b) using a local availability of an item sought by the end user, (c) using an advertiser attributes (e.g. a location of the advertiser's closest retail outlet), etc. Ads can be ordered and/or priced using language criteria (e.g., query/display language, information derived about user or advertiser's language such as location of user in Japantown). Although some examples above used geolocation information as a current location of the user, the geolocation information may be a location that the user is interested in. For example, if a search query includes a zip code, it may be inferred that the user is interested in a location defined by the zip code, or located within in the zip code. If the search query includes a city name, region name, and/or a state name, it may be inferred that the user is interested in a location defined by such a name(s). Thus, for example, a user may be interested in an area which may be the same as, or different from, the current area of the user. The targeting, scoring, content, and/or performance tracking of ads may be affected using a location of interest. § 4.3 CONCLUSIONS In view of the foregoing, the present invention allows more relevant ads to be served by using location information. | <SOH> § 1. BACKGROUND OF THE INVENTION <EOH>§ 1.1 Field of the Invention The present invention concerns advertising. In particular, the present invention concerns improving advertising using location information. §1.2 Related Art Advertising using traditional media, such as television, radio, newspapers and magazines, is well known. Unfortunately, even when armed with demographic studies and entirely reasonable assumptions about the typical audience of various media outlets, advertisers recognize that much of their ad budget is simply wasted. Moreover, it is very difficult to identify and eliminate such waste. Recently, advertising over more interactive media has become popular. For example, as the number of people using the Internet has exploded, advertisers have come to appreciate media and services offered over the Internet as a potentially powerful way to advertise. Advertisers have developed several strategies in an attempt to maximize the value of such advertising. In one strategy, advertisers use popular presences or means for providing interactive media or services (referred to as “Websites” in the specification without loss of generality) as conduits to reach a large audience. Using this first approach, an advertiser may place ads on the home page of the New York Times Website, or the USA Today Website, for example. In another strategy, an advertiser may attempt to target its ads to more narrow niche audiences, thereby increasing the likelihood of a positive response by the audience. For example, an agency promoting tourism in the Costa Rican rainforest might place ads on the ecotourism-travel subdirectory of the Yahoo Website. An advertiser will normally determine such targeting manually. Regardless of the strategy, Website-based ads (also referred to as “Web ads”) are often presented to their advertising audience in the form of “banner ads”—i.e., a rectangular box that includes graphic components. When a member of the advertising audience (referred to as a “viewer” or “user” in the Specification without loss of generality) selects one of these banner ads by clicking on it, embedded hypertext links typically direct the viewer to the advertiser's Website. This process, wherein the viewer selects an ad, is commonly referred to as a “click-through” (“Click-through” is intended to cover any user selection.). The ratio of the number of click-throughs to the number of impressions of the ad (i.e., the number of times an ad is displayed or otherwise rendered) is commonly referred to as the “click-through rate” or “CTR” of the ad. A “conversion” is said to occur when a user consummates a transaction related to a previously served ad. What constitutes a conversion may vary from case to case and can be determined in a variety of ways. For example, it may be the case that a conversion occurs when a user clicks on an ad, is referred to the advertiser's Web page, and consummates a purchase there before leaving that Web page. Alternatively, a conversion may be defined as a user being shown an ad, and making a purchase on the advertiser's Web page within a predetermined time (e.g., seven days). In yet another alternative, a conversion may be defined by an advertiser to be any measurable/observable user action such as, for example, downloading a white paper, navigating to at least a given depth of a Website, viewing at least a certain number of Web pages, spending at least a predetermined amount of time on a Website or Web page, etc. Often, if user actions don't indicate a consummated purchase, they may indicate a sales lead, although user actions constituting a conversion are not limited to this. Indeed, many other definitions of what constitutes a conversion are possible. The ratio of the number of conversions to the number of impressions of the ad (i.e., the number of times an ad is displayed or otherwise rendered) is commonly referred to as the conversion rate. If a conversion is defined to be able to occur within a predetermined time since the serving of an ad, one possible definition of the conversion rate might only consider ads that have been served more than the predetermined time in the past. The hosts of Websites on which the ads are presented (referred to as “Website hosts” or “ad consumers”) have the challenge of maximizing ad revenue without impairing their users' experience. Some Website hosts have chosen to place advertising revenues over the interests of users. One such Website is “Overture.com,” which hosts a so-called “search engine” service returning advertisements masquerading as “search results” in response to user queries. The Overture.com Website permits advertisers to pay to position an ad for their Website (or a target Website) higher up on the list of purported search results. If such schemes where the advertiser only pays if a user clicks on the ad (i.e., cost-per-click) are implemented, the advertiser lacks incentive to target their ads effectively, since a poorly targeted ad will not be clicked and therefore will not require payment. Consequently, high cost-per-click ads show up near or at the top, but do not necessarily translate into real revenue for the ad publisher because viewers don't click on them. Furthermore, ads that viewers would click on are further down the list, or not on the list at all, and so relevancy of ads is compromised. Search engines, such as Google for example, have enabled advertisers to target their ads so that they will be rendered in conjunction with a search results page responsive to a query that is relevant, presumably, to the ad. Although search result pages afford advertisers a great opportunity to target their ads to a more receptive audience, search result pages are merely a fraction of page views of the World Wide Web. Some online advertising systems may use ad relevance information and document content relevance information (e.g., concepts or topics, feature vectors, etc.) to “match” ads to (and/or to score ads with respect to) a document including content, such as a Web page for example. The foregoing ad serving systems can be thought of as keyword-targeted systems (where ads are targeted using terms found in a search query) and content-targeted systems (where ads are targeted using content of a document). Although keyword-targeted and content-targeted ad systems have improved the usefulness of ads, and consequently their performance (e.g., in terms of click-through rate, conversion rate, etc.), there is still plenty of room for improvement. Such improvement can be expected with better targeting. The Google keyword ad server allows advertisers to specify (e.g., for purposes of targeting) one or more countries in which their ad may be served. This permits ads to be served to particular users who presumably speak and understand a particular language. Unfortunately, however, many businesses have only a regional or local reach. For example, a restaurant may want to target ads only to potential customers within a 30 minute drive. A dry cleaner may want to target ads only to potential customers in the same town, and perhaps a few neighboring towns. As another example, a regional chain of drug stores may only want to target ads to potential customers living within their region. Even if such businesses have ads that are relevant to a search query or a Web page, if the end user viewing a search results Web page or the content of a Web page is outside the geographic reach of their business, the ads will not be very useful and will not perform well. If ads only generate revenue (e.g., for a content owner or ad system) when they perform well (e.g., if they are selected), such ads will generate little, if any, revenue. Such businesses often advertise in local papers and the telephone book yellow pages. While such conduits for advertisements are useful, they are limited. Such businesses may also advertise on local Websites, but this requires the business to find local Websites, and to track and manage advertising on each of the Websites. In view of the foregoing, there is a need for improving the usefulness, and consequently the performance, of advertisements. In particular, there is a need to allow businesses to better target their ads to a responsive audience. | <SOH> § 2. SUMMARY OF THE INVENTION <EOH>The present invention improves the usefulness, and consequently the performance, of advertisements. The present invention allows businesses to better target their ads to a responsive audience. The present invention may do so by determining and using location information, such as country, region, metro area, city or town, postal zip code, telephone area code, etc. The present invention may also use location information when determining a relevancy score of an ad. The present invention may also use location information in an attribute (e.g., position) arbitration. Such location information may be associated with price information, such as a maximum price bid. Such location information may be associated with ad performance information. The present invention may also track ad performance information on the basis of location information. The present invention may select or modify the content of an ad creative, and/or of a landing page using location information. For example, location information may be inserted into an ad creative. As another example, different landing pages with different content can be used for different locations. The present invention may also provide tools, such as user interfaces, to allow a business to enter and/or modify location information, such as location information used for targeting and location-dependent price information. | 20040412 | 20100223 | 20050303 | 76306.0 | 1 | ROBINSON, GRETA LEE | DETERMINING AND/OR USING LOCATION INFORMATION IN AN AD SYSTEM | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,823,524 | ACCEPTED | Adjustable exercise bell | This invention pertains to an improved adjustable kettlebell that has a stack of standard weight plates, a rounded grip section, a support bar serving to hold the weight stack, and flexible attachment members with cutouts for the support bar. The flexible attachment members provide a mechanically compliant clamping arrangement to accommodate weight stack of varying widths, and the cutouts allowing adjustment to the relative distance between the grip axis and the support bar axis. The improved adjustable kettlebell of the current invention serves as a close physical approximation to a solid cast kettlebell with a wide combination of standard weight plates. | 1. An adjustable kettlebell comprising: a handle with a grip section; one or more attachment members, wherein the one or more attachment members are configured deformable between a first position and a second position with a resilient mechanical compliance; a support bar, aligned along a weight plate axis, substantially parallel to the handle grip section axis; at least one weight stack; and an adjustable plurality of weight plates. 2. The device of claim 1, wherein said attachment members resiliently deflect to clamp tightly against a variety of weight stack widths. 3. The device of claim 1, wherein a segment of said attachment members can flex within the grip section. 4. The device of claim 1, wherein said supporting bar has a smooth overall profile lacking in excessive protrusions. 5. The device of claim 1, wherein said supporting bar comprised a bolts/washer combination tightened on either side of elongated nut. 6. The device of claim 1, wherein said supporting bar comprises an elongated nut, a captive washer and at least one bolts/washer combination. 7. The device of claim 1, having a roughly hemispherical end caps to further approximate a spheroidal shape of a solid kettlebell. 8. The device of claim 1, wherein a protective band surrounding the weight stack accommodates different form factors and provides additional padding. 9. An adjustable kettlebell, having a grip section, at least one attachment member, a support bar, at least one weight stack, capable of supporting an adjustable plurality of weight plates, wherein the at least one attachment member is configured to be deformable between a first position and a second position with a resilient mechanical compliance and said supporting bar is aligned along a weight plate axis, nominally parallel to the axis of the grip-section of the handle; and wherein said attachment members are configured to provide an adjustable distance between the grip section and the weight plate axis. 10. The device of claim 9, wherein said attachment members resiliently deflect to clamp tightly against a variety of weight stack widths. 11. The device of claim 9, wherein a segment of said attachment members can flex within the grip section. 12. The device of claim 9, wherein said supporting bar has a smooth overall profile lacking in excessive protrusions. 13. The device of claim 9, wherein said supporting bar comprised a bolts/washer combination tightened on either side of an elongated nut. 14. The device of claim 9, wherein said supporting bar comprises an elongated nut, a captive washer and at least one bolts/washer combination. 15. The device of claim 9, having a roughly hemispherical end caps to further approximate a spheroidal shape of a solid kettlebell. 16. The device of claim 9, wherein a protective band surrounding the weight stack accommodates different form factors and provides additional padding. 17. An adjustable kettlebell, comprising: a handle with a grip section, at least one attachment member, a support bar, at least one weight stack, capable of supporting an adjustable plurality of weight plates, wherein the at least one attachment member is configured to be deformable between a first position and a second position with a resilient mechanical compliance and said supporting bar is aligned along a weight plate axis, which is nominally parallel to a handle grip-section axis; and wherein said at least one attachment member is configured to provide an adjustable distance between the grip section and the plate axis, and wherein said at least one attachment member is flexibly configured to clamp tightly against weight stack of different widths. 18. The adjustable kettlebell in claim 1, wherein the one or more attachment members are each configured with an asymmetric cross-section. 19. The adjustable kettlebell in claim 18, wherein the asymmetric cross-section is configured with a greater breadth in a direction perpendicular to the weight plate axis then in a direction parallel to the weight plate axis. 20. The adjustable kettlebell of claim 1, wherein the one or more attachment members are configured with an internal pivot point. 21. The adjustable kettlebell of claim 1, wherein the one or more attachment members are configured with an asymmetric mechanical compliance. 22. The adjustable kettlebell of claim 1, wherein the one or more attachment members are configured to provide an adjustable distance between the grip section and the weight plate axis. | FIELD OF THE INVENTION The present invention relates to exercise equipment. More particularly, this invention pertains to an adjustable kettlebell of an improved, compact design that can employ standard barbell plates. BACKGROUND OF THE INVENTION In the specification, “dumbbell” defines an exercise device with two weight sections, connected by a handle section, while “kettlebell” defines a single mass section (often spheroidal) attached to single looped handle section. While many exercises can be performed with both kettlebells and dumbbells, some motions are more comfortably performed with a kettlebell or provide a unique benefit that is distinct from the nearest dumbbell equivalent. However, several kettlebell exercises such as the one arm clean (OAC) and the one arm snatch (OAS) require a degree of technique to avoid the kettlebell bashing against the user's forearm. The impact force is confined to a relatively small contact area, and bruising and discomfort can often result. Limitations of Existing Adjustable Kettlebell Designs In both the OAS and OAC exercise motions, a solid kettlebell provides a rounded surface that distributes both the impact and resting load of the kettlebell's mass. The primary disadvantage of a solid kettlebell design is that several kettlebells of varying weights are required to accommodate a range of exercises and strength levels. Previous adjustable kettlebell designs have had deficiencies in that they employ nonstandard weights and/or fail to provide adequate roundedness and comfort in the final configuration. A first adjustable kettlebell design was created by CALVERT (described in U.S. Pat. No. 1,316,683 issued to Milo Barbell Company). It comprises a handle attached to an outer shell surrounding a set of specialized weights. The following features and deficiencies of the design used in CALVERT are addressed by the improvements of the present invention. In CALVERT, (1) non-standard weight plates are required; and (2) the handle clearance, the distance between the handle and the point of contact between the forearm and the mass section, is fixed. Another adjustable type of kettlebell design is WOOD (described in U.S. Pat. No. 1,917,566 issued to Robert Alfred Wood). WOOD describes four major configurations of prior art designs. WOOD describe a design with an accommodation for standard barbell plates inside of an outer shell. Wood discloses the two cups of the outer shell with the edges presented outwards. WOOD also discloses a continuous stack of plates secured by collars to a bar, all within the confines of the attachment member. In another configuration, WOOD discloses a modified form of the handle, assembled with several of the discs at each end of the bell configuration, the cup members being omitted. WOOD does not reveal or describe several important features, namely, (1) a configuration that approximates the smooth surfaces found in the solid forged kettlebell without requiring a separate outer shell member; (2) a configuration where plates of the weight stack straddle the attachment members; (3) a configuration free of stop collars which avoids wide, awkward protrusions; and (4) a “solid” configuration that prevents sway of the main weight section with regard to the handle, along with an attachment mechanism that provides for an adjustable handle clearance. While WOOD contemplates a configuration with a solid handle (a wire bail), it does not describe a means to combine the solid handle with an adjustable handle clearance. Furthermore, adding additional chain links to the configurations described by WOOD will only increases the relative sway. Another design for an adjustable kettlebell was implemented by GRACE (Gracefitness). It involves a gnurled handle, a set of specialized bevel discs, and a set of twisted steel bars functioning as a means of attachment between the weight discs and the gnurled handle. The following features and deficiencies of the GRACE design are addressed by the improvements of the present invention. GRACE requires (1) specialized beveled plates are required to form the rounded surface near the line of contact; (2) that the handle clearance is a fixed distance from the contact point; and (3) the plate axis is perpendicular the handle's axis, hence adjusting the number of weights changes the point of contact. Two more adjustable designs that use standard barbell plates, are manufactured by Piedmont Design Associates (PDA). The deficiencies of the PDA designs are as follows: (1) the use of retaining collars results in significant gaps in the spacing of the weight plates that straddle the attachment member; (2) the use of retaining collars results in significant protrusions on the outside of the bell configuration; (3) the handle clearance between the handle and the bar is fixed. Another kettlebell design has been designed by IRONMIND (Ironmind). It implements the plate axis to be perpendicular to the handle axis, but requires careful consideration of the weight stack configuration to avoid having the weight plate edges come to rest with the forearm during some exercises. This design and instructions from manufacturers indicate their awareness of the shortcomings of this arrangement and discourage all exercise motions that involve the weight resting on the forearms. SUMMARY AND OBJECT OF THE INVENTION In light of the deficiencies, shortcomings and drawbacks of the known kettlebell designs, it is therefore an object to provide an improved kettlebell weightlifting device which includes an adjustable configuration that provides for a plurality of standard weight discs forming a weight stack with a central plate axis. It is further object of the current invention to provide a supporting bar aligned along the plate axis, this axis being nominally parallel to the axis of the grip section of the handle. It is another object of the current invention to provide a rounded grip section that affords comforting grip to the user. It is also an object of the current invention to provide attachment members that afford significantly reduced gaps between weight discs that straddle said attachment sections. It is further desirable that these attachment members are structured as to provide an adjustable distance between the grip section and the plate axis. These and other objectives, characteristics and advantages of the present invention will be disclosed in more detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a partially exploded elevation view of one embodiment of the present invention. FIG. 1B is a side view of an implementation of an attachment member illustrated in FIG. 1A from the perspective of reference character AA. FIG. 1C is a side view of another implementation of an attachment member illustrated in FIG. 1A from the perspective of reference character AA. FIG. 2 is an elevation view of the present invention highlighting the flexure of the attachment structure. FIG. 3 is a side view of one embodiment of the present invention, showing the rounded handle, weight discs, and the “forearm”. FIGS. 4A-4C are a schematic representation of the present invention, showing three additional configurations in accordance with the current invention, showing a narrow configuration with large plates and hemispherical end caps in FIG. 4A, a narrow configuration with small plates and hemispherical end caps in FIG. 4B, and a narrow configuration with small plates, hemispherical end caps and a protective band in FIG. 4C. DETAILED DESCRIPTION OF THE INVENTION FIG. 1A shows an elevation view of one embodiment of the present invention in 5 partial disassembly. A curved and rounded handle assembly is comprised of a grip section 1 and an attachment member or “blade” 14. The “blade” 14 intersects the stack of disc weights 18 with a minimal gap 16 introduced between weight plates. The subassembly of the bolts 34, 35, washers 91 and the elongated nut 28 forming a support bar 70 for the weight stack. In this particular embodiment, an elongated hexnut 28 with a captive washer 90 welded to one end, is passed through a central disc stack 96 from the left until the captive washer 90 meets the outside face of the left blade, while the right bolt 35 is passed through an outside washer 91 and rightmost weight assembly 92 and threaded into the hexnut 28 from the right, and the left bolt 34 is passed through the leftmost weight assembly 94 and threaded into 28 from the left. As the bolts are tightened down, the gap 88 between the outside weight assemblies 94 and 92 and center weight stack 96 reduces to the thickness of the attachment members 14—the final configuration forming a single, physically tight assembly. The subassembly of the bolts 34, 35 and the elongated hexnut 28 forming a support bar 70 assembly for the weight stack. Section AA #1 shows the cross section of the blades 14 with distinct holes 20 for different positions of the bar. Section AA #2 shows the cross section of the blades 14 with a scalloped hole pattern 22 that provide for a finer adjustment of support bar positions. The adjustable hand clearance 98 feature is demonstrated with the center line 24 aligned with holes AA #1, and the center line 25 aligned with sections AA #2. Distinct holes 20, or small nibs 23 in the hole pattern 22 can provide a hard mechanical stop for the hexnut 28. Alternately, the design can rely solely on the friction of a tightened support bar to set and maintain a specific handle clearance 98. In FIG. 8, the support bar 70 is comprised of the left bolt 34, elongated nut 28 with captive washer 90 and right bolt 35. With various combinations of outside bolts (34 and 35) and a 4″ long hexnut 28, the length of the support bar can safely span a range of 4″ to 10″. Other features of this invention may include the following additional elements: 1) since the captive washer 90 provides access to the internal thread of the hexnut 28, the right weight assembly 92 can be modified without rearranging either the core 96 or the left weight assembly 94; 2) additional combinations of inside and outside bolts can provide additional lengths, if necessary; 3) either or both outside weight assemblies may be omitted. Alternately, the support bar can be configured as a variety of other mechanical arrangements that effectively result in a shaft of adjustable length. Moreover, a support bar can be comprised of a solid or hollow tube along with standard securing mechanisms, such as spring, spiral clamps or large pitch spiral threads, with the proviso that such configurations can introduce additional protrusions past the outside weight assemblies. By defining an attachment member 10 with various hole configurations of 20 or 22 (see FIG. 1A-1C) the present invention allows for an adjustment of the distance between support bar 70 axis 24 and the grip axis, and provides the key improvement that the user can adjust the optimum contact point 32 independently of the diameter of the weight plates that are used. FIG. 2 illustrates another aspect of the present invention. The blade section 14 is part of a single piece of bent spring material 74 (preferably spring steel), that is embedded in a partially hollow grip-section 1 with outside profile 82. A bar 74 is bent to a profile that fits snugly against the internal webs 80 of an otherwise hollow grip section 1 which could be constructed by joining two halves of either stamped metal or molded material (for example, ABS plastic). The internal webs 80 function to secure part of the bar member 74 between pivot points 76. Below the pivot points 76, there is an internal clearance 98 that allows the bar 74 to flex within the hollow grip-section 1. As the bolt 35 is threaded against the elongated hexnut 28, the blades 14 flex into a new profile 78. Additionally, if the nominal hex pattern 22 is cut into the blade attachment members 14, then the hexnut 28 can be restrained from spinning even if the core weight stack 96 width is greater than the hexnut's length. This safety feature prevents the inadvertent loosening of one bolt while the user tightens the other bolt. Additionally, by setting the pivot point 76 far from the bottom of the grip-section 1, the present invention achieves greatly increased mechanical compliance of the blades 14, allowing the blades to clamp tightly against a central plate assembly 96 of vary width without excessive stress being placed on the blades or the grip-section 1. FIG. 3 shows the side view of the kettlebell configuration, with a grip-section 1 leading into the attachment member blades 14 that intersperse the weight stack. The inner stack of weights is comprised of larger weight discs 18 (e.g., 10 pounds), while the outer edges of the stack are comprised of smaller weight discs 17 (e.g., 5 pounds). The forearm 40 is shown in schematic representation along with the range of motion 30 of the forearm. In this view, the contact point 32 between the forearm 40 and the weight stack shows the critical nature of the hand clearance (the distance between the support bar axis 24 and the grip axis). If this clearance is too small then the weight's leverage against the wrist can impose excessive pressure at the contact point. If this clearance is too large, then the flipping action (described in the OAS and OAC motions above) of the kettlebell allows for excessive acceleration of the weight stack prior to terminating at the contact point 32. FIGS. 4A-4C show some additional configurations of the present invention. Configuration 64 in FIG. 4A shows a weight stack comprised of four ten pound discs 18 along with hemispherical end caps 48 all aligned on centerline axis 44. The hemispherical end caps 48 would have a deep countersunk hole that would allow for bolt head and support bar (not shown in this drawing) to pass through the majority of the hemispherical end cap. The final configuration nearly approximates the hemispherical shape of the original solid kettlebell. The hemispherical end caps could be made of any material. A metal cap would provide additional weight, while caps made of plastic, foam, wood or other light material provide the desired shape without significant addition weight or requirement for a specialized forging. Configuration 66 in FIG. 4B, shows a weight stack comprised of four 5 pound discs 17 along with smaller hemispherical end caps 49 all aligned on centerline axis 46. Substantially less weight is involved (20 vs 40 pounds), but the optimal contact point is preserved by adjusting the centerline 46. The smaller hemispherical end caps 49 have all the characteristics of their larger counterparts 48 in configuration 64. Configuration 68 in FIG. 4C, shows a weight stack comprised of four 5 pound discs 17 along with the larger hemispherical end caps 48, and a protective band 50 around the weight stack, all aligned on centerline axis 44. The weight stack of 17, spherical end caps 48 and protective band 50 comprising an entirely spheroidal shape of relatively low weight and large size, are envisioned for the less aggressive user. The hemispherical caps and/or protective band can be manufactured out of a dense shock absorbing foam for additional comfort and protection. While there have been shown and described, pointed fundamental novel features of the invention as applied to embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of the invention, as herein disclosed, may be made by those skilled in the art without departing from the spirit of the invention. In particular all weights and dimensions introduced in the specification were presented for illustrative purposes, and variations in said weights and dimensions are anticipated and will not affect the utility of the present invention. It is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. It is the intention, therefore to be limited only as indicated by the scope of the claims appended hereto. | <SOH> BACKGROUND OF THE INVENTION <EOH>In the specification, “dumbbell” defines an exercise device with two weight sections, connected by a handle section, while “kettlebell” defines a single mass section (often spheroidal) attached to single looped handle section. While many exercises can be performed with both kettlebells and dumbbells, some motions are more comfortably performed with a kettlebell or provide a unique benefit that is distinct from the nearest dumbbell equivalent. However, several kettlebell exercises such as the one arm clean (OAC) and the one arm snatch (OAS) require a degree of technique to avoid the kettlebell bashing against the user's forearm. The impact force is confined to a relatively small contact area, and bruising and discomfort can often result. | <SOH> SUMMARY AND OBJECT OF THE INVENTION <EOH>In light of the deficiencies, shortcomings and drawbacks of the known kettlebell designs, it is therefore an object to provide an improved kettlebell weightlifting device which includes an adjustable configuration that provides for a plurality of standard weight discs forming a weight stack with a central plate axis. It is further object of the current invention to provide a supporting bar aligned along the plate axis, this axis being nominally parallel to the axis of the grip section of the handle. It is another object of the current invention to provide a rounded grip section that affords comforting grip to the user. It is also an object of the current invention to provide attachment members that afford significantly reduced gaps between weight discs that straddle said attachment sections. It is further desirable that these attachment members are structured as to provide an adjustable distance between the grip section and the plate axis. These and other objectives, characteristics and advantages of the present invention will be disclosed in more detail with reference to the attached drawings. | 20040412 | 20060530 | 20060216 | 83698.0 | A63B2316 | 0 | HWANG, VICTOR KENNY | ADJUSTABLE EXERCISE BELL | SMALL | 0 | ACCEPTED | A63B | 2,004 |
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10,823,620 | ACCEPTED | Machine spindle having a gas spring-operated tool-clamping mechanism | A machine spindle includes a casing and a clamping mechanism disposed in the casing. The clamping mechanism includes front and rear drawbars which are relatively movable axially within the casing. A gas spring biases the rear drawbar rearwardly, and a force transmitting mechanism transmits such rearward motion to the front drawbar for moving the front drawbar rearwardly. In response to its rearward movement, the front drawbar actuates a clamp for clamping a tool. The gas spring includes a housing disposed in the casing and defining a gas chamber having a front wall through which the rear drawbar extends. The gas spring also includes a piston disposed in the gas chamber for axial movement therein. The piston is releasably connected to a rear end of the rear drawbar by a releasable coupling disposed in the chamber. | 1. A machine spindle comprising: a casing defining a center axis; and a clamping mechanism disposed in the casing, the clamping mechanism comprising: a front drawbar having axially spaced front and rear ends, the front end carrying a tool clamp operable to clamp a tool in response to rearward movement of the front drawbar, a rear drawbar arranged behind the front drawbar; a force transmitting mechanism for transmitting rearward motion of the rear drawbar to the front drawbar for movement of the front drawbar rearwardly; a gas spring for biasing the rear drawbar rearwardly, comprising: a housing disposed in the casing and defining a gas chamber having a front wall through which the rear drawbar extends, and a piston disposed in the gas chamber for axial movement therein and releasably connected to a rear end of the rear drawbar by a releasable coupling disposed in the chamber. 2. The machine spindle according to claim 1 wherein the releasable coupling comprises a threaded coupling. 3. The machine spindle according to claim 2 wherein the threaded coupling comprises a male thread formed on the rear drawbar, and a female thread formed in the piston. 4. The machine spindle according to claim 1 wherein the rear drawbar includes a radial flange disposed in front of the front wall of the chamber and arranged to abut the front drawbar and the front wall during front and rear movement, of the rear drawbar. 5. The machine spindle according to claim 4 wherein the force-transmitting mechanism comprises a force-amplifier wedge arrangement disposed in front of the flange. | This application claims priority under 35 U.S.C. §119 to Patent Application Serial No. 0301108-7 filed in Sweden on Apr. 15, 2003, the entire content of which is hereby incorporated by reference. TECHNICAL FIELD OF THE INVENTION The present invention relates to a gas spring included in a machine spindle having clamping member. The gas spring comprises a housing, a first drawbar arranged in the housing, a piston connected with the first drawbar, which piston is axially displaceable in the housing, as well as a gas medium contained in the housing. The first drawbar is connected in a force-transmitting manner to a second drawbar that is connected to the clamping member. DESCRIPTION OF THE PRIOR ART From SE-C-515 002 (corresponding to Anderson U.S. Pat. No. 6,722,827), a clamping device is previously known comprising a gas spring, which has a one-piece drawbar. When gas springs of the kind in question are filled with gas medium when they are delivered to a customer, it is necessary to block the drawbar against the displacement that the contained pressure medium aims to apply to the drawbar. This blocking is made by providing the drawbar with a stop member, which is attached to the part of the drawbar that is outside the housing of the gas spring. In the area of the free end thereof, the drawbar has a member, usually a thread, for connection with a thread of an additional drawbar, which is included in a force-amplifier. This threaded joint takes up space in the axial direction and the total axial length of the threaded joint and the stop member is significant. OBJECTS AND FEATURES OF THE INVENTION A primary object of the present invention is to provide a gas spring of the kind defined in the introduction where the components included in the gas spring are so formed that the assembly of the components is facilitated and that the risk of damaging seals included in the gas spring is reduced. Another object of the present invention is that when the gas spring is integrated with a force-amplifier, the total length of these generally should be as short as possible. Yet an object of the present invention is that the mounting of the gas spring according to the present invention in a machine spindle should be facilitated. At least the primary object of the present invention is realised by a machine spindle which comprises a casing defining a center axis, and a clamping mechanism disposed in the casing. The clamping mechanism comprises front and rear drawbars, a force transmitting mechanism, and a gas spring. The front drawbar has axially spaced front and rear ends. The front end carries a tool clamp which is operable to clamp a tool in response to rearward movement of the front drawbar. The rear drawbar is arranged behind the front drawbar. The force transmitting mechanism is arranged for transmitting rearward motion of the rear drawbar to the front drawbar to move the front drawbar rearwardly. The gas spring is arranged for biasing the rear drawbar rearwardly and comprises a housing and a piston. The housing is disposed in the casing and defines a gas chamber having a front wall through which the rear drawbar extends. The piston is disposed in the gas chamber for axial movement therein and is releasably connected to a rear end of the rear drawbar by a releasable coupling disposed in the chamber. BRIEF DESCRIPTION OF THE DRAWINGS Below, an example of prior art as well as an embodiment of the invention will be described, reference being made to the accompanying drawings. FIG. 1A shows a machine spindle according to prior art, a. force-amplifier according to prior art being included in the machine spindle. FIG. 1 shows a machine spindle having a force-amplifier according to the present invention, the machine spindle also comprising a newly developed gas spring. FIG. 2 shows in detail essential components of the force-amplifier in the starting position. FIG. 3 shows separately two wedges included in the force-amplifier. FIG. 4 shows in detail the essential components of the force-amplifier in an intermediate position. FIG. 5 shows in detail the essential components of the force-amplifier in a position where the force is raised. FIG. 6 shows a detail of a drawbar included in the force-amplifier. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION The conventional machine spindle shown in FIG. 1A comprises a casing B, which is rotationally symmetrical in respect of a longitudinal centre axis C-C of the machine spindle. The casing B has an internal, through-channel D, which has a circular cylindrical cross-section and is symmetrical in respect of the centre axis C-C, i.e., the centre axis C-C also constitutes the centre axis of the channel D, which has varying cross-section along the length thereof in order to enable assembly of the different components included in the machine spindle. In the channel D, a clamping mechanism of the machine spindle is arranged that comprises a gas spring E, a force-amplifier F as well as a clamping member G, the force-amplifier F being situated between the gas spring E and the clamping member G. As is seen in FIG. A, a drawbar H of the gas spring E slides within a housing K and is interconnected with a second drawbar I of the force-amplifier F by means of a threaded joint J, which accordingly is located between the gas spring E and the force-amplifier F. On the part of the first drawbar H that is outside a housing K of the gas spring E, a stop member L in the shape of a ring is applied. The machine spindle shown in FIG. 1 comprises a casing 1, which is rotationally symmetrical in respect of a longitudinal centre axis C-C of the machine spindle. The casing 1 has an internal, through channel 3, which has a substantially circular cylindrical cross-section and is symmetrical in respect of the centre axis C-C, i.e., the centre axis C-C also constitutes the centre axis of the channel 3, which has varying cross-section along the length thereof in order to enable assembly of the different components included in the machine spindle. In the channel 3, a clamping mechanism of the machine spindle is arranged that comprises a gas spring 5, a force-amplifier 7 as well as a conventional clamping member 9, the force-amplifier 7 being situated between the gas spring 5 and the clamping member 9. The gas spring 5 comprises a housing 6 having an end portion 8, at the left end of the gas spring 5 in FIG. 1. The drawbar 10 slides within the housing 6. As is seen in FIG. 1, a one-piece first, or front, drawbar 10 extends from the right end of the gas spring 5 to the area of the force-amplifier 7. In that connection, the front (left) end of the first drawbar 10 in FIG. 1 is received in an axially extending recess 4 of a second, or rear, drawbar 11, in relation to which the first drawbar 10 can move in the longitudinal direction by a limited distance. A spring 12 arranged between the front end of the first drawbar 10 and a recess of the second drawbar 11 damps the same motion. When the first drawbar 10 is displaced forwardly (towards the left in FIG. 1), the spring 12 will push the second drawbar 11 also forwardly (towards the left) before a flange 17 of the first drawbar 10 gets into contact with the second drawbar 11. At its front end, the second drawbar 11 has a male thread 13, which cooperates with a female thread 14 of an activating means 15 of the clamping member 9. Thus, the male thread 13 and the female thread 14 together form a first threaded joint. The second drawbar 11 is included as part of the force-amplifier 7 and both the second drawbar 11 and the activating means 15 are axially displaceable in the channel 3 of the casing 1. The clamping member 9 also comprises segments 16 which in an initial phase of assembly or disassembly of a tool are stationary in relation to the casing 1 in the longitudinal direction thereof. Said segments 16 are actuated by the activating means 15 when the same is displaced axially in the channel 3, the free ends of the segments 16 moving in radial and axial directions and effecting clamping of a tool coupling, for instance, of the type Coromant Capto®. This is prior art, which therefore is not described in detail. As may be seen in FIG. 1, the first drawbar 10 is provided with a flange 17 in the area of the first drawbar 10 that is between the housing 6 of the gas spring 5 and the force-amplifier 7. In the position of the machine spindle shown in FIG. 1, the flange 17 has come to abutment against the front end of the gas spring 5. During passage of the first drawbar 10 through the front end of the gas spring 5 in FIG. 1, the first drawbar 10 is sealed in a conventional way. In the area of the rear (right) end of the gas spring 5 in FIG. 1, the first drawbar 10 is provided with a male thread 18, which cooperates with a female thread 19 of a piston 20 of the gas spring 5, which piston is displaceable in relation to the housing 6 of the gas spring 5. In that connection, the piston 20 is, in a conventional way, sealed against the housing 6 wherein the housing 6 and the piston 20 together define an internal space 21 of the gas spring 5, in which space a gas medium, normally nitrogen gas, is contained. The gas medium has a pressure that is higher than the atmospheric pressure. Upon a comparative study of the machine spindles according to FIG. 1A and FIG. 1, respectively, it is seen that the machine spindle according to FIG. 1 has a smaller length than the known machine spindle according to FIG. 1A. This has been enabled by the fact that the threaded joints J and 18/19, respectively, between the parts of the drawbar H and 10, respectively, have mutually different positions in the machine spindle. Thereby, a shortening of the length of the first drawbar 10 has been provided in comparison with the length of the drawbar H. The threaded joint 18/19 at the piston 20 has been arranged without this part of the first drawbar 10 having needed to be extended, however, a minor increase of the diameter has been made in connection with the arrangement of the threaded joint 18/19. However, said increase of the diameter is, in practice, of no importance. The machine spindle according to the present invention also comprises a force-amplifier 7, which will be described more in detail below, reference being made to FIGS. 2-6. The force-amplifier 7 comprises the part of the first drawbar 10 located outside the housing 6 of the gas spring 5 as well as the second drawbar 11, which accordingly are axially displaceable in the channel 3 of the casing 1. The force-amplifier 7 also comprises a number of sets of cooperating wedges, the force-amplifier 7 comprising three such sets that are evenly distributed along the circumference of the internal channel 3. Each set of cooperating wedges of the force-amplifier 7 comprises a first, or radially inner, wedge 22 as well as a second, or radially outer, wedge 23, said wedges 22 and 23 being arranged in an appurtenant countersink 24 in the first drawbar 10. Thereby, the radial space requirement for each set of wedges 22, 23 is reduced. In FIG. 3, the wedges 22 and 23 are shown separately. The first wedge 22 has a first sliding surface 31, a second sliding surface 32, a third sliding surface 33 and a fourth sliding surface 34, the fourth sliding surface 34 being situated in the plane of the paper in FIG. 3. All said sliding surfaces are planar and oriented at an oblique angle relative to the axis C-C. The mutual angles between adjacent sliding surfaces are preferably obtuse. The second wedge 23 has a fifth sliding surface 35 and a sixth sliding surface 36, said two sliding surfaces 35, 36 preferably being planar. The mutual angle between the same sliding surfaces 35, 36 is preferably obtuse. The second wedge 23 also has a first support surface 41 and a second support surface 42, said support surfaces 41, 42 in the embodiment illustrated having an extension perpendicular to each other. The second wedge 23 also has a side surface 43 having a notch 44, the side surface 43 generally having an extension transverse to the fifth and sixth sliding surfaces 35, 36. Preferably, the sliding surfaces and the side surfaces of the wedges 22 and 23 have a friction-reducing coating. The second drawbar 11 of the force-amplifier 7 is provided with a number of radial grooves 50, see FIG. 6, the number of grooves 50 corresponding to the number of sets of wedges, i.e., one set of wedges 22, 23 is received in each groove 50. As may be seen in FIG. 6, the groove 50 has a generally elongate shape in the longitudinal direction of the second drawbar 11 and the groove 50 widens towards a rear end thereof in the axial direction of the second drawbar 11. The first wedge 22, which cooperates with this end of the groove 50, has a corresponding shape. The countersink 24 is also provided with a bulge 51 on one side wall thereof, said bulge 51 being intended to cooperate with the notch 44 of the second wedge 23. Furthermore, the groove 50 has, in the area of the widened end thereof, an eighth sliding surface 58, which generally has an extension transverse to the centre axis C-C of the machine spindle. In the force-amplifier 7, also an anvil 55 is included in the form of a sleeve, which is arranged in the internal channel 3 and encircles the second drawbar 11, the anvil 55 abutting against a shoulder 56 in the internal channel 3. At the end thereof turned from the shoulder 56, the anvil 55 has a sloping, seventh sliding anvil surface 57 which is oriented obliquely relative to the axis C-C and intended to cooperate with the first sliding surface 31 of the first wedge 22. The first planar sliding surface 31 and the seventh planar sliding surface 57 have an inclination of approx. 45° to the centre axis C-C of the machine spindle. The anvil 55 is stationarily mounted in the internal channel 3, i.e., the anvil 55 abuts permanently against the shoulder 56. The above-described force-amplifier 7 operates in the following way. In FIG. 2, the force-amplifier 7 is shown in the starting position, wherein the free end of the second drawbar 11 abuts against the flange 17 of the first drawbar 10. In this position, the first drawbar 10 is accordingly displaced maximally towards the front (left in FIG. 2), this being effected by means of an external hydraulic piston (not shown) or the like, which pushes against the rear (right) end of the first drawbar 10, see FIG. 1. The forward (leftward) displacement of the second drawbar 11 is effected against the action of the pressure medium contained in the gas spring 5. In that connection, the segments 16 are in the radially innermost positions thereof and a desired tool may be mounted on the clamping member 9. When the force from the external hydraulic piston is relieved or otherwise enables the first drawbar 10 to move towards the rear in FIG. 2, under the action of energy stored in the gas spring 5, the transitional phase shown in FIG. 4 will be initiated. In that connection, the direct abutment between the second drawbar 11 and the flange 17 of the first drawbar 10 will cease. The rearward displacement of the first drawbar 10 in FIG. 4 causes a displacement of the second planar sliding surface 32 of the first wedge 22 to occur in relation to the fifth planar sliding surface 35 of the second wedge 23. The second planar sliding surface 32 of the first wedge 22 and the fifth planar sliding surface 35 of the second wedge 23 have an inclination of approx. 65° to the centre axis C-C of the machine spindle. In that connection, the first wedge 22 will move radially outwardly, which means that the first planar sliding surface 31 of the first wedge 22 will be displaced along the seventh planar sliding surface 57 of the anvil 55 at the same time as the fourth planar sliding surface 34 of the first wedge 22 is displaced. in relation to the eighth planar sliding surface 58 of the groove 50 in the second drawbar 11. Since the anvil 55 is stationary, the radial displacement outwardly of the first wedge 22 will mean that a certain axial rearward displacement of the second drawbar 11 takes place in FIG. 4. A continued relative displacement between the first wedge 22 and the second wedge 23 eventually results in the cooperation between the second planar sliding surface 32 and the fifth planar sliding surface 35 ceasing, and then the third planar sliding surface 33 of the first wedge 22 will begin cooperation with the sixth planar sliding surface 36 of the second wedge 23, see FIG. 5. Thereby, the force-amplifying phase has been initiated. Since the third sliding surface 33 and the sixth sliding surface 36 have a substantially smaller inclination in relation to the centre axis C-C of the machine spindle than the second sliding surface 32 and the fifth sliding surface 35, the relative displacement between the third sliding surface 33 and the sixth sliding surface 36 will generate a smaller radial displacement outwardly of the first wedge 22 for a corresponding axial displacement of the first drawbar 10 in comparison with the above-described relative displacement between the second sliding surface 32 and the fifth sliding surface 35. However, the force applied from the surface 35 of the second wedge 23 to the surface 33 of the wedge 22 now has a larger component in the radially outward direction, which, via the surfaces 31, 57, results in an amplification of the axial rearward force that is applied to the second drawbar 11. That amplification occurs at the transition from cooperation between the second sliding surface 32 and the fifth sliding surface 35 to cooperation between the third sliding surface 33 and the sixth sliding surface 36. During the cooperation between the third sliding surface 33 and the sixth sliding surface 36, the transfer of the force to the second drawbar takes place as before, i.e., the first sliding surface 31 of the first wedge 22 cooperates with the seventh sliding surface 57 of the anvil 55 and the fourth sliding surface 34 of the first wedge 22 transfers the axial force to the eighth sliding surface 58 of the second drawbar 11. In general it is the case that the mutually cooperating sliding surfaces 32 and 35, and 33 and 36, respectively, of the cooperating wedges 22, 23 are parallel with each other, whereby a satisfactory surface contact is guaranteed, as compared to a less desirable line contact. Also the first sliding surface 31 of the first wedge 22 is parallel with the seventh sliding surface 57 of the anvil 55. Upon study of FIG. 6, it is realized that the cooperating design of the widened part of the groove 50 and the conicity of the first wedge 22 result in that the wedge 22 cannot be axially displaced but can be displaced solely radially in relation to the second drawbar 11. As for the second wedge 23, it is, as has been pointed out above, provided with a notch 44 that in the mounted position of the second wedge 23 cooperates with a bulge 51 of the countersink 24. Thereby, it is guaranteed that the second wedge 23 follows the first drawbar 10 when the same moves from the position according to FIG. 5 to the position according to FIG. 2. FEASIBLE MODIFICATIONS OF THE INVENTION In the above-described embodiment, the first drawbar 10 and the piston 20 are connected by means of a threaded joint. However, within the scope of the present invention, alternative ways of dismountably connecting the first drawbar 10 and the piston 20 are also conceivable, wherein, for an exemplifying and not limiting purpose, a bayonet coupling may be mentioned, the same being locked in connecting position by means of, for instance, some type of locking screw. Neither it is necessary that the threaded joint is located in connection with the piston 20 but, as far as space admits, the threaded joint may, for instance, be located on an intermediate area of the first drawbar 10. Although the present invention has been described in connection with a preferred embodiment thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without departing from the spirit and scope of the invention as defined in the appended claims. | <SOH> TECHNICAL FIELD OF THE INVENTION <EOH>The present invention relates to a gas spring included in a machine spindle having clamping member. The gas spring comprises a housing, a first drawbar arranged in the housing, a piston connected with the first drawbar, which piston is axially displaceable in the housing, as well as a gas medium contained in the housing. The first drawbar is connected in a force-transmitting manner to a second drawbar that is connected to the clamping member. | <SOH> BRIEF DESCRIPTION OF THE DRAWINGS <EOH>Below, an example of prior art as well as an embodiment of the invention will be described, reference being made to the accompanying drawings. FIG. 1A shows a machine spindle according to prior art, a. force-amplifier according to prior art being included in the machine spindle. FIG. 1 shows a machine spindle having a force-amplifier according to the present invention, the machine spindle also comprising a newly developed gas spring. FIG. 2 shows in detail essential components of the force-amplifier in the starting position. FIG. 3 shows separately two wedges included in the force-amplifier. FIG. 4 shows in detail the essential components of the force-amplifier in an intermediate position. FIG. 5 shows in detail the essential components of the force-amplifier in a position where the force is raised. FIG. 6 shows a detail of a drawbar included in the force-amplifier. detailed-description description="Detailed Description" end="lead"? | 20040414 | 20060307 | 20050106 | 79331.0 | 0 | ROSS, DANA | MACHINE SPINDLE HAVING A GAS SPRING-OPERATED TOOL-CLAMPING MECHANISM | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,823,727 | ACCEPTED | Modular access floor system with airseal gasket | An access floor assembly is provided that comprises a plurality of abutting access floor panels that are attached to a plurality of pedestals. A resilient and flexible gasket is provided between the abutting floor panels to provide an effective seal between the panels. The effective seal allows a pre-determined pressure to be maintained in a plenum located between the access floor panels and a sub-floor. Air under pressure in the plenum may be delivered in a controlled and consistent manner from the plenum to a space above the access floor assembly. | 1. An access floor assembly for installation on a sub-floor, the access floor assembly comprising: a plurality of elongate support members, each of said support members having a base for attachment to said sub-floor, and a head longitudinally spaced from said base; a plurality access floor panels, each said access floor panel defining a top planar surface and an opposed bottom planar surface, each said bottom surface being detachably connectable to the head of at least one of said support members, each of the access floor panels defining a plurality of peripheral edges for abutting a peripheral edge of a respective access floor panel; and a plurality of gaskets for providing an air tight seal between the peripheral edges of abutting access floor panels; each of said gaskets having first portion for attachment to one of said floor panels and a flexible and resilient sealing portion for creating a seal between the peripheral edges of the abutting access floor panels. 2. An access floor assembly according to claim 1 wherein each said access floor panel defines 4 peripheral edges. 3. An access floor assembly according to claim 2 wherein each said access floor panel is attached to four pedestals. 4. An access floor assembly according to claim 3 wherein a corner of each said access floor panel is attached to one of the four pedestals by way of a fastener. 5. An access floor assembly according to claim 1 wherein the first portion of each of said gaskets has an elongate trim portion and the resilient portion has a convex profile that is resiliently depressible into a flattened profile. 6. An access floor assembly according to claim 3 wherein each of said plurality of gaskets abuts another one of said plurality of gaskets to form an air seal when the access floor assembly is installed. 7. An access floor assembly according to claim 1 wherein each of said gaskets is integrally formed on one of said peripheral edges of one of said floor panels. 8. An access floor assembly according to claim 1 wherein each of said gaskets is adhered to one of said peripheral edges of one of said floor panels. 9. An access floor assembly according to claim 1 wherein the pedestals are formed of galvanized steel. 10. An access floor assembly according to claim 1 wherein the gaskets are formed of a flexible and resilient material. 11. An access floor assembly according to claim 1 wherein the assembly defines a plenum between said sub floor and said access floor panels when the assembly is installed. 12. An access floor panel for attachment to a pedestal of an access floor assembly, the access floor panel comprising: a top planar surface and an opposed bottom planar surface, said bottom surface being detachably connectable to said pedestal, said access floor panel defining a plurality of peripheral edges; and a plurality of gaskets, one said gasket being attached to each of said peripheral edges, said gaskets each having a first portion attached a respective said peripheral edge and a flexible and resilient sealing portion adapted to create a seal between said respective peripheral edge and a peripheral edge of an abutting access floor panel. 13. An access floor panel according to claim 12 wherein the first portion of said gaskets has an elongate trim portion and the resilient portion is has convex profile that is resiliently depressible into a flattened profile. 14. An access floor panel according to claim 12 wherein the access floor panel has 4 peripheral edges. 15. An access floor panel according to claim 12 wherein each of said gaskets is formed of a flexible and resilient material. 16. An access floor panel according to claim 11 wherein the access floor panel and the gasket are attached in one of an interlocking arrangement and by an adhesive. | FIELD OF THE INVENTION The present invention relates to access floor systems. BACKGROUND OF THE INVENTION Access floor systems are widely used in modem office buildings. These floors are also referred to as elevated floors or computer floors. Access floor systems were initially used in computer rooms for cooling applications because computers generate a great deal of heat and to accommodate the extensive electrical wiring requirements. Today, access floors are also widely used in commercial office construction. Access floor systems provide a space between the access floor and a base floor to accommodate the electrical and mechanical systems, building controls, communication wiring and other components required for operating the building. Access floor panels are removable which allows easy access to the wiring, components and electrical outlets. The flooring of access floor systems is provided by a plurality of square floor panels. Access floor systems include a plurality of pedestals that support the square shaped floor panels. The pedestals of access floor systems in the past supported a plurality of metal stringers that formed a frame for supporting the perimeter of each of the square floor panels. U.S. Pat. No. 3,396,501 provides an example of such a stringer-based system. Stringer based systems are disadvantageous however because they are expensive and the stringer frame imposes a permanently installed structure that makes access to components and services under the floor more difficult. Stringer less systems have been developed wherein the pedestals directly support the corners of the square floor panels. Canadian Patent No. 946,578 provides an example of such a system. This patent describes an access floor system that can be structured as either a stringer type assembly or a stringer less type assembly. The floor panels of these systems may leave a gap around the perimeter of the floor panels that permits a flow of air through the access floor. In buildings with under floor air this may be disadvantageous as this airflow loss makes it difficult and or inefficient to maintain air pressure under the access floor. This is a significant drawback because a specified air pressure is required beneath the access floor for ventilation purposes in order to deliver air from beneath the access floor to the space above the floor in a consistent and controlled manner. However, air cannot be delivered in an efficient way through diffusers in the floor panels in an access floor if there is a high level of leakage in through the floor panel edges. There is therefore a need for a modular stringer less access floor system wherein the floor panels are sealed effectively to provide an air pressure beneath the access floor that permits air to be delivered to a space from beneath the floor in a controlled and efficient manner. SUMMARY OF THE INVENTION The present invention provides a stringer less modular access floor having floor panels that are effectively sealed to maintain a specified pressure level beneath the access floor for delivering air to a space above the floor in a controlled manner. The access floor system of the present invention comprises a plurality of pedestals that support a plurality of access floor panels. The panels are sealed by flexible self-adjusting gaskets. According to one aspect of the present invention there is provided an access floor assembly for installation on a sub-floor. The access floor assembly comprises a plurality of elongate support members. Each of the support members has a base for attachment to the sub-floor, and a head longitudinally spaced from the base. The access floor assembly also has a plurality of access floor panels. Each of the access floor panels defines a top planar surface and an opposed bottom planar surface. Each of the bottom surfaces is detachably connectable to the head of at least one of the support members. Each of the access floor panels defines a plurality of peripheral edges for abutting a peripheral edge of a respective access floor panel. The access floor assembly has a plurality of gaskets for providing an airtight seal between the peripheral edges of abutting access floor panels. Each of the gaskets has a first portion for attachment to one of the floor panels and a flexible and resilient sealing portion for creating a seal between the peripheral edges of the abutting access floor panels. According to another aspect of the present invention there is provided an access floor panel for attachment to a pedestal of an access floor assembly. The access floor panel comprises a top planar surface and an opposed bottom planar surface. The bottom surface is detachably connectable to the pedestal. The access floor panel defines a plurality of peripheral edges and a plurality of gaskets. One of the gaskets is attached to each of the peripheral edges. The gaskets each have a first portion attached to one of the peripheral edges and a flexible and resilient sealing portion adapted to create a seal between the peripheral edge to which the first portion is attached and a peripheral edge of an abutting access floor panel. BRIEF DESCRIPTION OF THE DRAWINGS In drawings which illustrate by way of example only a preferred embodiment of the invention, FIG. 1 is a front perspective view of a modular access system of the present invention; FIG. 2 is an exploded view of a pedestal and floor panel of the present invention; FIG. 3 is a cross-sectional view taken along lines 3-3 of FIG. 1; FIG. 4 is a cross-sectional view taken along lines 4-4 of FIG. 1; FIG. 5 is a side profile of a gasket of the present invention; and FIG. 6 is a sectional view showing a diffuser installed in floor panel of the invention; and FIG. 7 is an exploded view of the diffuser. DETAILED DESCRIPTION OF THE INVENTION As shown in FIG. 1, modular access floor assembly 1 comprises a plurality of floor panels 4. The floor panels 4 are preferably square shaped having four peripheral edges 38 and four corner portions 30. Other embodiments of the present invention may have floor panels with three peripheral edges. The floor panels 4 preferably define bores 48 through the corner portions 30 as seen in FIG. 2. Each of the floor panels 4 has a top planar surface 34 and a bottom planar surface 36. The floor panels 4 abut respective floor panels 4 along peripheral edges 38 of the floor panels 4. As best shown in FIGS. 3 and 4, each peripheral edge 38 has a flange portion 40 and a rib portion 42. Each peripheral edge 38 defines a channel 52 between the flange portion 40 and the rib portion 42. The floor panels are preferably constructed of a metal frame with a centre core. The centre core may include a variety of materials including wood. The surface is preferably applied with an adhesive. Each of the floor panels preferably measures approximately 24″ by 24″ ″ and has a thickness of approximately 1″ (25.4 mm). A person skilled in the art will appreciate that the floor panels can be made with various measurements and from various materials known in the art. Air is moved from the plenum area 60 to the surface above by various means such as passive and active devices. A passive method is by diffuser and an active method is by means of a mechanical floor diffuser commonly known as a VAV (variable air volume). Both systems require that a predetermined pressure be maintained in the plenum 60 located below the access floor. The floor panels 4 preferably have diffusers 70 installed therein for allowing air to pass through in a controlled manner when the air has reached a pre-determined pressure level. The diffusers are installed into the floor panels according to methods known in the art such that air can move transversely through the plane of the floor panels. FIG. 6 illustrates how a diffuser 70 can be installed into a floor panel 4. The diffuser 70 has a carpet flange 74 that abuts the top surface 34 of the floor panel 4. A mounting clamp 76 is attached to the diffuser 70 and abuts the bottom surface 36 of the floor panel 4. The diffuser may have a dust trap 72 that preferably rotates to adjust outlet airflow. FIG. 7 is an exploded view of a diffuser that is used as part of the present invention. The diffuser 70 has the dust trap 72 that receives an adjustable damper 92. The diffuser 70 also has the carpet flange 74 and a diffuser lid 94. A mechanical floor diffuser may be employed that is commonly referred to as a VAV (variable air volume). This diffuser may be installed into the floor according to methods known in the art such that air is moved transversely through the floor at various controlled delivery volumes. As best shown in FIGS. 3 and 4, a gasket 20 is attached to each of the four peripheral edges 38 of the floor panels 4. Each gasket 20 extends along the entire length of the peripheral edge 38 to which it is attached. The gasket 20 therefore forms a trim along the length of the peripheral edge 38 of the floor panel 4 to which it is attached, as shown in FIG. 2. The gasket 20 is shown in side profile in FIG. 5. The gasket 20 has a flange portion 22, a trim portion 24 and a resilient sealing portion 26. The resilient sealing portion is preferably concave in shape and preferably protrudes” beyond the trim portion 24. As shown in FIGS. 3 and 4, the trim portion 24 of the gasket is received in the channel 52 of the peripheral edge 38 to which it is attached. The flange portion 22 of the gasket is attached to the rib portion 42 of the floor panel 4. The flange portion 40 of the peripheral edge 38 abuts trim portion 24 of the gasket 20 such that the gasket is securely attached to the floor panel 4 in the channel 52. The gasket 20 is constructed of a flexible and resilient material that is preferably a synthetic polymer such as flexible polyvinyl chloride. The gasket 20 may also be constructed of other flexible and resilient materials. The gasket member is preferably installed onto the peripheral edge 38 during manufacture so that it cannot be removed. The gasket 20 appears as a trim along the length of the peripheral edge 38 to which it is attached. In an alternate embodiment of the invention, the gasket may be constructed of other synthetic, organic or inorganic materials. In this alternate embodiment, the gasket may be attached to the floor panel 4 by way of an adhesive. The access floor assembly shown in FIG. 1 includes a plurality of pedestals 8 that function as support members for the access floor system. The pedestals each have a base plate 14 that attaches to a sub-floor 50 of a building shown in FIG. 2. The base is connected to an elongate post 28. The post 28 terminates in a threaded rod portion 10 that attaches to a head plate 12. An adjusting nut 18 is attached to the threaded rod portion 10. The nut has projections that prevent it from rotating on the post 28. The head plate 12 is planar and preferably square shaped. The head plate preferably defines a plurality of threaded bores 32 about a periphery thereof. Most preferably, the head plate 12 has four corners 46 and defines a threaded bore 32 near each of the four corners 46. As shown in FIG. 2, a corner 30 of one of the floor panels 4 preferably attaches to a corner 46 of the head plate. A threaded fastener 16 preferably attaches the floor panels 4 to the head plates 10 through clearance holes 48 and threaded bores 32. The clearance hole 48 is preferably 5/16″ in diameter. As shown in FIG. 2, each head plate 12 is adapted to attach to four floor panels 4 by attachment through the threaded bores 32. The base and head plate are made in varying thicknesses and dimensions depending on the various requirements and conditions. The post 28 can be any height for the purposes of the present invention. The post, base and head plates are all preferably constructed of steel, although they can be made from other materials The access floor system of the present invention is a modular system that can be assembled and disassembled. It is useful to disassemble portions the access floor in order to install cables below the access floor, access services below the access floor or to work under the access floor. In an assembled position, the access floor assembly comprises a plurality of abutting floor panels 4 that form a continuous floor as shown in FIG. 1. With the exception of a floor panel 4 located at one of the peripheries, each of the floor panels 4 abuts four other floor panels. With the further exception of a floor panel 4 located at one of the peripheries of the access floor assembly 1, each of the four peripheral edges 38 of each floor panel 4 abuts a peripheral edge 38 of another floor panel 4. In the assembled position, each of the four corners 30 of each floor panel 4 is attached to a different head plate 12 of a different pedestal 8. Therefore, when the access floor assembly 1 is in the assembled position, with the exception of the pedestals 8 located along the periphery of the access floor assembly 1, each pedestal 8 is attached to four different floor panels 4. Preferably, the four corners 46 of the head plates 12 are each attached to a corner 30 of a different floor panel 4. As shown in FIGS. 3 and 4, in the assembled position, the peripheral edges 38 of respective floor panels 4 are in abutment. The sealing portions 26 of respective gasket members 20 of the respective floor panels 4 are also in abutment. The resilient and flexible sealing portions 26 compress and flatten when they are in abutment to form a tight seal. Because the sealing portion 26 is resilient and flexible, the sealing portion 26 returns to its original position as shown in FIG. 5, without any damage to the gasket when a floor panel 4 is removed from the assembly 1. Therefore, the floor panels 4 can be removed from the access floor assembly 1 and replaced without affecting the performance of the seal provided by abutting gasket members 20. The access floor assembly shown in FIG. 1 defines a plenum 60 between the access floor and the sub-floor. The plenum 60 can supply air-conditioned air to the space above the access floor through the diffusers. When the access floor assembly 1 is assembled, the air in the plenum 60 is maintained under pressure due the seals provided by the gaskets 20. The pressure in the plenum is maintained in a predetermined design range. At this pressure level, air is delivered to the space above the access floor in a controlled manner through the diffusers or mechanical devices. The seal between the abutting floor panels 4 provided by the abutting gasket members 20 allows an air leakage rate of air from the plenum through the access floor panels 4 to be maintained at a minimum. As a result, it is possible to maintain the required pressure in the plenum for proper air circulation through the diffusers or mechanical devices without having to deliver an overly abundant volume of air to the plenum. The access floor assembly 1 has a periphery and four peripheral sides. In some designs a plenum flashing 56 as shown in FIG. 3, is attached to each of the peripheral sides of the access floor system 1. The plenum flashing is preferably made of galvanized steel. The plenum flashing 56 has an upper portion 57 that is located near an underside 36 of the floor panel 4. A plenum gasket 54 is located between the underside 36 of the floor panel 4 and the upper portion 57 and forms a seal therebetween. An acoustic caulking 58 is preferably attached to the plenum flashing 56 by way of fastener 59. Preferably, the plenum flashing 56 has a base 51 that is attached to the sub-floor 50 by way of anchor members 53. Preferably the anchor members 53 are Hilti™ anchor members that are attached to the base every 24″ along the length of the base. The plenum flashing 56 is preferably located ¼″ from the base plate 14 of the nearest pedestal 8. The access floor assembly can be readily disassembled. This is accomplished by removing one or more of the floor panels 4 from the head plates 46 to which they are attached by removing the fasteners 16. The removal of one or more of the floor panels 4 permits easy access to the plenum 60 beneath the floor for access to services and cables located beneath the floor. The pedestals 8 are fixed to the sub-floor 50 either with a conventional adhesive or by mechanical anchors. The pedestals 8 can be easily removed once the floor panels have been removed from the head plates. This is accomplished by loosening the adjusting nut 18. The pedestal head 12 can be removed when the floor panels 4 are removed. The pedestal base 14 is preferably glued to the sub-floor 50. The floor panel 4 is preferably manufactured by forming a shaped flat sheet of metal into a bottom pan of approx. 24″ square, with an approx 1″ (25.4 mm) lip. This part is preferably applied on an interior surface with adhesive and a 1″ (25.4 mm) centre core panel that is also preferably applied with an adhesive is placed into the bottom pan. The gasket 20 is constructed from a flexible and resilient material that has a hooked upper section that is hooked over the top edge of the formed lip of the bottom pan. Prior to attachment to a floor panel, the edge trim is cut to an exact length. Four pieces of trim are attached as described on each of the four sides of the square panel bottom pan. When cutting gaskets to length, the ends are also cut to a shape. A metal top pan, is also formed into a pan with a lip edge. This top pan is also applied inside with adhesive and then placed on top of a sub assembly of centre core, bottom pan, and trim. Various embodiments of the present invention having been thus described in detail by way of example, it will be apparent to those skilled in the art that variations and modifications may be made without departing from the invention. The invention includes all such variations and modifications as fall within the scope of the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>Access floor systems are widely used in modem office buildings. These floors are also referred to as elevated floors or computer floors. Access floor systems were initially used in computer rooms for cooling applications because computers generate a great deal of heat and to accommodate the extensive electrical wiring requirements. Today, access floors are also widely used in commercial office construction. Access floor systems provide a space between the access floor and a base floor to accommodate the electrical and mechanical systems, building controls, communication wiring and other components required for operating the building. Access floor panels are removable which allows easy access to the wiring, components and electrical outlets. The flooring of access floor systems is provided by a plurality of square floor panels. Access floor systems include a plurality of pedestals that support the square shaped floor panels. The pedestals of access floor systems in the past supported a plurality of metal stringers that formed a frame for supporting the perimeter of each of the square floor panels. U.S. Pat. No. 3,396,501 provides an example of such a stringer-based system. Stringer based systems are disadvantageous however because they are expensive and the stringer frame imposes a permanently installed structure that makes access to components and services under the floor more difficult. Stringer less systems have been developed wherein the pedestals directly support the corners of the square floor panels. Canadian Patent No. 946,578 provides an example of such a system. This patent describes an access floor system that can be structured as either a stringer type assembly or a stringer less type assembly. The floor panels of these systems may leave a gap around the perimeter of the floor panels that permits a flow of air through the access floor. In buildings with under floor air this may be disadvantageous as this airflow loss makes it difficult and or inefficient to maintain air pressure under the access floor. This is a significant drawback because a specified air pressure is required beneath the access floor for ventilation purposes in order to deliver air from beneath the access floor to the space above the floor in a consistent and controlled manner. However, air cannot be delivered in an efficient way through diffusers in the floor panels in an access floor if there is a high level of leakage in through the floor panel edges. There is therefore a need for a modular stringer less access floor system wherein the floor panels are sealed effectively to provide an air pressure beneath the access floor that permits air to be delivered to a space from beneath the floor in a controlled and efficient manner. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides a stringer less modular access floor having floor panels that are effectively sealed to maintain a specified pressure level beneath the access floor for delivering air to a space above the floor in a controlled manner. The access floor system of the present invention comprises a plurality of pedestals that support a plurality of access floor panels. The panels are sealed by flexible self-adjusting gaskets. According to one aspect of the present invention there is provided an access floor assembly for installation on a sub-floor. The access floor assembly comprises a plurality of elongate support members. Each of the support members has a base for attachment to the sub-floor, and a head longitudinally spaced from the base. The access floor assembly also has a plurality of access floor panels. Each of the access floor panels defines a top planar surface and an opposed bottom planar surface. Each of the bottom surfaces is detachably connectable to the head of at least one of the support members. Each of the access floor panels defines a plurality of peripheral edges for abutting a peripheral edge of a respective access floor panel. The access floor assembly has a plurality of gaskets for providing an airtight seal between the peripheral edges of abutting access floor panels. Each of the gaskets has a first portion for attachment to one of the floor panels and a flexible and resilient sealing portion for creating a seal between the peripheral edges of the abutting access floor panels. According to another aspect of the present invention there is provided an access floor panel for attachment to a pedestal of an access floor assembly. The access floor panel comprises a top planar surface and an opposed bottom planar surface. The bottom surface is detachably connectable to the pedestal. The access floor panel defines a plurality of peripheral edges and a plurality of gaskets. One of the gaskets is attached to each of the peripheral edges. The gaskets each have a first portion attached to one of the peripheral edges and a flexible and resilient sealing portion adapted to create a seal between the peripheral edge to which the first portion is attached and a peripheral edge of an abutting access floor panel. | 20040414 | 20090331 | 20051110 | 71403.0 | 1 | SPAHN, GAY | METAL FRAMED FLOOR PANEL HAVING FLANGE OUTWARD OF RIB WITH U-SHAPED PORTION OF GASKET OVER TOP OF RIB, PORTION OF GASKET BETWEEN RIB AND FLANGE, AND CONVEX SEALING PORTION OF GASKET BELOW FLANGE AND OUTWARD OF RIB | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,823,781 | ACCEPTED | System and method for attenuating the effect of ambient light on an optical sensor | The present invention provides systems and methods for attenuating the effect of ambient light on optical sensors and for measuring and compensating quantitatively for the ambient light. | 1. A method for compensating for ambient light that may reach a photodetector system of an optical sensor having indicator molecules, comprising: illuminating the indicator molecules, thereby causing the indicator molecules to emit light; determining the amount of light reaching the photodetector system at a point in time when the indicator molecules are illuminated, thereby determining the sum of the amount of ambient light and the light emitted from the indicator molecules reaching the photodetector; ceasing illuminating the indicator molecules; after ceasing illuminating the indicator molecules, determining the amount of light reaching the photodetector system, thereby determining the amount of ambient light reaching the photodetector; and determining the amount of light emitted from the indicator molecules that reached the photodetector system by subtracting the second determined amount of light from the first determined amount of light. 2. The method of claim 1, further comprising transmitting signals to a sensor reader, wherein each signals contains information corresponding to an output of the photodetector system. 3. The method of claim 1, wherein the step of determining the amount of light emitted from the indicator molecules that reached the photodetector system by subtracting the second determined amount of light from the first determined amount of light is performed by an external sensor reader. 4. The method of claim 1, wherein the step of illuminating the indicator molecules comprises activating a light source. 5. The method of claim 4, wherein the step of activating the light source comprises driving the light source with about 2 milliamps of current. 6. The method of claim 1, wherein the step of determining the amount of light reaching the photodetector consists of obtaining a signal output from the photodetector system. 7. A method for compensating for ambient light that may reach a photodetector system of an optical sensor having indicator molecules, comprising: (a) illuminating the indicator molecules; (b) capturing a first signal output from the photodetector system, wherein said first signal is a function of the intensity of the light striking a photosensitive surface or surfaces of the photodetector system; (c) after performing step (b) and while the indicator molecules are not being illuminated, capturing a second signal output from the photodetector system, wherein said second signal is a function of the intensity of the light striking a photosensitive surface or surfaces of the photodetector system; and (d) generating a third signal, wherein the third signal is a function of the first and second signal. 8. The method of claim 7, further comprising transmitting the first and second signal to a sensor reader. 9. The method of claim 8, wherein the sensor reader generates the third signal. 10. The method of claim 7, wherein the step of generating the third signal comprises subtracting the second signal from the first signal. 11. The method of claim 7, wherein the step of illuminating the indicator molecules comprises activating a light source. 12. The method of claim 11, wherein the step of activating the light source comprises driving the light source with about 2 milliamps of current. 13. An optical sensor, comprising: indicator molecules; a photodetector; a light source for illuminating the indicator molecules; means for determining the amount of light reaching the photodetector at a point in time when the indicator molecules are illuminated by the light source, thereby determining the sum of the amount of ambient light and the light emitted from the indicator molecules reaching the photodetector; and means for determining the amount of light reaching the photodetector at a point in time when the indicator molecules are not being illuminated by the light source, thereby determining the amount of ambient light reaching the photodetector. 14. The optical sensor of claim 13, further comprising means for determining the amount of light emitted from the indicator molecules that reached the photodetector. 15. The optical sensor of claim 14, wherein said means for determining the amount of light emitted from the indicator molecules that reached the photodetector comprises means for subtracting the second determined amount of light from the first determined amount of light. 16. The optical sensor of claim 13, further comprising a transmitter for transmitting a signal to a sensor reader, wherein the signal contains information about the amount of light reaching the photodetector at a point in time when the indicator molecules are illuminated by the light source. 17. The optical sensor of claim 13, further comprising means for activating the light source by driving the light source with about 2 milliamps of current. 18. The optical sensor of claim 13, wherein the means for determining the amount of light reaching the photodetector comprises means for obtaining a signal output from the photodetector. 19. The optical sensor of claim 13, further comprising a housing for housing said determining means, said photodetector and said light source. 20. The optical sensor of claim 19, wherein the indicator molecules are disposed on an outer surface of the housing. 21. An optical sensor, comprising: indicator molecules; a photodetector system; a light source for illuminating the indicator molecules; means for capturing a first signal output from the photodetector system while the indicator molecules are in a fluorescent state, wherein said first signal is a function of the intensity of the light striking a photosensitive surface or surfaces of the photodetector system; and means for capturing a second signal output from the photodetector system while the indicator molecules are not being illuminated, wherein said second signal is a function of the intensity of the light striking a photosensitive surface or surfaces of the photodetector system. 22. The optical sensor of claim 21, further comprising means for generating a third signal, wherein the third signal is a function of the first and second signal. 23. The optical sensor of claim 22, wherein the means for generating the third signal comprises means for subtracting the second signal from the first signal. 24. The optical sensor of claim 21, further comprising a transmitter for transmitting the first and second signal to a sensor reader. 25. The optical sensor of claim 21, further comprising a housing for housing said determining means, said photodetector and said light source. 26. The optical sensor of claim 25, wherein the indicator molecules are disposed on an outer surface of the housing. 27. The optical sensor of claim 21, further comprising means for activating the light source by driving the light source with about 2 milliamps of current. 28. A sensor, comprising: a housing; a circuit board housed within the housing, the circuit board having a hole created there through and defining a passageway from a top surface of the circuit board to a bottom surface of the circuit board; at least one photodetector mounted to the bottom surface of the circuit board, the at least one photodetector having a light sensitive surface, said light sensitive surface being positioned so that light traveling through said passageway can strike said light sensitive surface. 29. The sensor of claim 28, wherein the circuit board is constructed from a material that does not propagate stray light. 30. The sensor of claim 28, wherein the circuit board comprises ferrite. 31. The sensor of claim 28, further comprising an optical filter, wherein at least a portion of said optical filter is disposed within said passageway. 32. The sensor of claim 31, wherein the optical filter is a high pass filter. 33. The sensor of claim 31, further comprising a second optical filter disposed in series with the first optical filter. 34. The sensor of claim 33, wherein the second optical filter is a NIR filter. 35. The sensor of claim 28, further comprising a light source mounted to the top surface of the circuit board. 36. The sensor of claim 28, further comprising a light blocking material disposed to prevent light from striking one or more sides of said at least one photodetector. 37. The sensor of claim 36, wherein the light blocking material comprises a black epoxy. 38. The sensor of claim 28, further comprising a plurality of indicator molecules mounted on an outer surface of the housing. 39. The sensor of claim 38, wherein the indicator molecules are contained within a polymer matrix layer that is disposed on the outer surface of the housing. 40. The sensor of claim 39, wherein the polymer matrix layer is highly porous. 41. The sensor of claim 38, further comprising a light source housed within said housing for illuminating the indicator molecules. 42. The sensor of claim 41, wherein the light source is mounted on the top surface of the circuit board. 43. The sensor of claim 41, further comprising: means for capturing a first signal output from the at least one photodetector while the indicator molecules are in a fluorescent state, wherein said first signal is a function of the intensity of the light striking a photosensitive surface or surfaces of the at least one photodetector; and means for capturing a second signal output from the at least one photodetector while the indicator molecules are not being illuminated, wherein said second signal is a function of the intensity of the light striking a photosensitive surface or surfaces of the at least one photodetector. 44. The sensor of claim 43, further comprising means for generating a third signal, wherein the third signal is a function of the first and second signal. 45. The sensor of claim 44, wherein the means for generating the third signal comprises means for subtracting the second signal from the first signal. 46. The sensor of claim 43, further comprising a transmitter for transmitting the first and second signal to a sensor reader. 47. The sensor of claim 43, further comprising means for activating a light source by driving the light source with about 2 milliamps of current. 48. A sensor, comprising: a housing; a ferrite circuit board housed within the housing; at least one photodetector mounted on the circuit board; a light source housed within the housing; a transmitter housed within the housing; and a plurality of indicator molecules disposed on an outer surface of the housing. 49. The sensor of claim 48, wherein the circuit board has a hole defining a passageway from a top surface of the circuit board to a bottom surface of the circuit board. 50. The sensor of claim 49, wherein the at least one photodetector is mounted to the bottom surface of the circuit board, the at least one photodetector having a light sensitive surface, said light sensitive surface being positioned so that light traveling through said passageway can strike said light sensitive surface. 51. The sensor of claim 50, further comprising an optical filter, wherein at least a portion of said optical filter is disposed within said passageway. 52. The sensor of claim 51, wherein the optical filter is a high pass filter. 53. The sensor of claim 51, further comprising a second optical filter disposed in series with the first optical filter. 54. The sensor of claim 53, wherein the second optical filter is a NIR filter. 55. The sensor of claim 50, wherein the light source is mounted on a top surface of the circuit board. 56. The sensor of claim 48, further comprising a light blocking material disposed to prevent light from striking one or more sides of said at least one photodetector. 57. The sensor of claim 56, wherein the light blocking material comprises a black epoxy. 58. The sensor of claim 48, wherein the indicator molecules are contained within a polymer matrix layer that is disposed on the outer surface of the housing. 59. The sensor of claim 58, wherein the polymer matrix layer is highly porous. 60. The sensor of claim 48, further comprising: means for capturing a first signal output from the at least one photodetector while the indicator molecules are in a fluorescent state, wherein said first signal is a function of the intensity of the light striking a photosensitive surface or surfaces of the at least one photodetector; and means for capturing a second signal output from the at least one photodetector while the indicator molecules are not being illuminated, wherein said second signal is a function of the intensity of the light striking a photosensitive surface or surfaces of the at least one photodetector. 61. The sensor of claim 60, further comprising means for generating a third signal, wherein the third signal is a function of the first and second signal. 62. The sensor of claim 61, wherein the means for generating the third signal comprises means for subtracting the second signal from the first signal. 63. The sensor of claim 60, further comprising a transmitter for transmitting the first and second signal to a sensor reader. 64. The sensor of claim 60, further comprising means for activating a light source by driving the light source with about 2 milliamps of current. 65. A sensor, comprising: a housing; at least one photodetector housed within the housing; a light source housed within the housing; a transmitter housed within the housing; and a plurality of indicator molecules contained within a polymer matrix layer that is disposed on an outer surface of the housing, wherein the polymer matrix layer is highly porous. 66. The sensor of claim 65, further comprising a circuit board housed within the housing, wherein the at least one photodetector is mounted on the circuit board. 67. The sensor of claim 66, wherein the circuit board is a ferrite circuit board. 68. The sensor of claim 66, wherein the circuit board has a hole defining a passageway from a top surface of the circuit board to a bottom surface of the circuit board, and the photodetector has at least one photosensitive surface that is positioned so that light traveling through said passageway can strike said light sensitive surface. 69. The sensor of claim 68, further comprising an optical filter, wherein at least a portion of said optical filter is disposed within said passageway. 70. The sensor of claim 69, wherein the optical filter is a high pass filter. 71. The sensor of claim 69, further comprising a second optical filter disposed in series with the first optical filter. 72. The sensor of claim 71, wherein the second optical filter is a NIR filter. 73. The sensor of claim 68, wherein the light source is mounted on the top surface of the circuit board and the at least one photodetector is mounted on the bottom surface of the circuit board. 74. The sensor of claim 65, further comprising a light blocking material disposed to prevent light from striking one or more sides of said at least one photodetector. 75. The sensor of claim 74, wherein the light blocking material comprises a black epoxy. 76. The sensor of claim 65, further comprising: means for capturing a first signal output from the at least one photodetector while the indicator molecules are in a fluorescent state, wherein said first signal is a function of the intensity of the light striking a photosensitive surface or surfaces of the at least one photodetector; and means for capturing a second signal output from the at least one photodetector while the indicator molecules are not being illuminated, wherein said second signal is a function of the intensity of the light striking a photosensitive surface or surfaces of the at least one photodetector. 77. The sensor of claim 76, further comprising means for generating a third signal, wherein the third signal is a function of the first and second signal. 78. The sensor of claim 76, wherein the means for generating the third signal comprises means for subtracting the second signal from the first signal. 79. The sensor of claim 76, further comprising a transmitter for transmitting the first and second signal to a sensor reader. 80. The sensor of claim 76, further comprising means for activating a light source by driving the light source with about 2 milliamps of current. 81. A sensor reader, comprising: a receiver for receiving a wireless signal transmitted from a sensor; a user interface for displaying information to a user of the sensor reader, wherein the information is related to information contained within said wireless signal; and a photodetector for detecting the intensity of ambient light. 82. The sensor reader of claim 81, further comprising a housing for housing the receiver, user interface and photodetector. 83. The sensor reader of claim 82, further comprising an opaque wrist band, wherein the housing is attached to the opaque wrist band. 84. The sensor reader of claim 81, further comprising a processor in communication with the receiver, photodetector and user interface. 85. The sensor reader of claim 84, wherein the processor is programmed to receive from the photodetector data corresponding to the intensity of said ambient light and is further programmed to issue an alert to the user if the data corresponding to the intensity of said ambient light indicates that the intensity is greater than a pre-determined threshold. 86. The sensor reader of claim 84, wherein the processor is programmed to (a) receive from the photodetector data corresponding to the intensity of said ambient light, (b) receive from the receiver data transmitted from the sensor, (c) compute a value that is based on the data received from the photodetector and the data received from the receiver; and (d) display the value on the user interface. 87. In a sensor reader having a photodetector, a receiver for receiving a signal from an optical sensor, and a user interface for receiving input from a user of the sensor reader and for providing the user with information, a method, comprising: determining the intensity of ambient light; determining whether the intensity of the ambient light is greater than a predetermined threshold intensity; and issuing a warning to the user if it is determined that the intensity of the ambient light is greater than the predetermined threshold intensity. 88. The method of claim 87, further comprising activating the sensor if it is determined that the intensity of the ambient light is less than the predetermined threshold intensity. 89. The method of claim 88, further comprising receiving a signal transmitted from the optical sensor, wherein the signal contains information relating to an analyte. 90. The method of claim 89, further comprising using information contained in the signal and the determined intensity of the ambient light to compute a value relating to the analyte. 91. The method of claim 89, further comprising outputting information to the user via the user interface, wherein the outputted information is a function of the information contained in the signal received from the optical sensor. 92. The method of claim 89, wherein the signal is transmitted wirelessly. 93. A sensor reader, comprising: a photodetector; a receiver for receiving a signal from an optical sensor; a user interface for receiving input from a user of the sensor reader and for providing the user with information: means for determining the intensity of ambient light; means for determining whether the intensity of the ambient light is greater than a predetermined threshold intensity; and means for issuing a warning to the user if it is determined that the intensity of the ambient light is greater than the predetermined threshold intensity. 94. The sensor reader of claim 93, further comprising means for activating the sensor in response to the determining means determining that the intensity of the ambient light is less than the predetermined threshold intensity. 95. The sensor reader of claim 94, wherein, after the sensor is activated, the receiver receives a signal transmitted from the optical sensor, wherein the signal contains information relating to an analyte. 96. The sensor reader of claim 95, further comprising means for using information contained in the signal and the determined intensity of the ambient light to compute a value relating to the analyte. 97. The sensor reader of claim 95, further comprising means for outputting information to the user via the user interface, wherein the outputted information is a function of the information contained in the signal received from the optical sensor. 98. The sensor reader of claim 95, wherein the signal is transmitted wirelessly. 99. The sensor reader of claim 93, further comprising a housing for housing the receiver, user interface and photodetector. 100. The sensor reader of claim 99, further comprising an opaque wrist band, wherein the housing is attached to the opaque wrist band. | The present application claims the benefit of U.S. Provisional Patent Application No. 60/462,695, filed Apr. 15, 2003. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical sensors, and, more specifically, to a system and method for attenuating the effect of ambient light on an optical sensor. 2. Discussion of the Background An optical sensor is a device that may be used to detect the concentration of an analyte (e.g., oxygen, glucose, or other analyte). U.S. Pat. No. 6,330,464, the disclosure of which is incorporated herein by reference, describes an optical sensor. There may be situations when it is desirable to use an optical sensor in an environment where there is a significant amount of ambient light (e.g., the outdoors on a bright, sunny day). In some circumstances, a significant amount of ambient light may negatively affect the accuracy of an optical sensor. Accordingly, what is desired are systems and methods to attenuate the negative effect of ambient light on the functioning of an optical sensor and/or to measure and compensate quantitatively for the ambient light. SUMMARY OF THE INVENTION The present invention provides systems and methods for attenuating the effect of ambient light on optical sensors and for measuring and compensating quantitatively for the ambient light. In one aspect, the present invention provides an optical sensor having features that attenuate the amount of ambient light that reaches the optical sensor's photodetectors. The features can be used together or separately. For example, in some embodiments, the present invention provides an optical sensor wherein the circuit board that is used to electrically connect the electrical components of the sensor is made from an opaque material (e.g., opaque ferrite), as opposed to the conventional aluminum oxide ceramic circuit board. In some embodiments, the photodetectors of the optical sensor are mounted to the bottom side of a circuit board and holes are made in the circuit board to provide a way for light from the indicator molecules to reach the photodetectors. In another aspect, the present invention provides methods for using and implanting an optical sensor, which methods, used together or separately, reduce the effect of ambient light on the optical sensor. For example, in one aspect the present invention provides a method that includes the following steps: illuminating indicator molecules, thereby causing the indicator molecules to emit light; determining the amount of light reaching a photodetector at a point in time when the indicator molecules are illuminated, thereby determining the sum of the amount of ambient light and the light emitted from the indicator molecules reaching the photodetector; ceasing illuminating the indicator molecules; after ceasing illuminating the indicator molecules, determining the amount of light reaching the photodetector, thereby determining the amount of ambient light reaching the photodetector; and determining the amount of light emitted from the indicator molecules that reached the photodetector by subtracting the second determined amount of light from the first determined amount of light. In another aspect, the present invention provides an improved sensor reader and method of operating the sensor reader. For example, in one aspect, the present invention provides a method performed by a sensor reader that includes the steps of: determining the intensity of ambient light; determining whether the intensity of the ambient light is greater than a predetermined threshold intensity; and issuing a warning to the user if it is determined that the intensity of the ambient light is greater than the predetermined threshold intensity. The above and other features and advantages of the present invention, as well as the structure and operation of preferred embodiments of the present invention, are described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated herein and form part of the specification, help illustrate various embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention. In the drawings, like reference numbers indicate identical or functionally similar elements. Additionally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears. FIG. 1 shows an optical sensor according to an embodiment of the present invention. FIG. 2 shows an optical sensor according to another embodiment of the present invention. FIG. 3 shows the top surface of a circuit board according to an embodiment of the present invention. FIG. 4 shows the field of view of a photodetector according to an embodiment of the present invention. FIG. 5 shows a sensor that has been implanted into a patient according to an embodiment of the present invention. FIG. 6 shows a sensor having outriggers according to an embodiment of the present invention. FIG. 7 shows a functional block diagram of a sensor reader according to an embodiment of the present invention. FIG. 8 is a flow chart illustrating a process, according to an embodiment of the present invention, that may be performed by a sensor reader. FIG. 9 is a flow chart illustrating a process for attenuating the effect of ambient light on readings provided by an optical sensor. FIG. 10 is a flow chart illustrating a process performed by a sensor according to an embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows an optical sensor (“sensor”) 110, according to an embodiment of the present invention, that operates based on the fluorescence of fluorescent indicator molecules 116. The sensor 110 includes a sensor housing 112 (sensor housing 112 may be formed from a suitable, optically transmissive polymer material), a matrix layer 114 coated over the exterior surface of the sensor housing 112, with fluorescent indicator molecules 116 distributed throughout the layer 114 (layer 114 can cover all or part of the surface of housing 112); a radiation source 118, e.g. an LED, that emits radiation, including radiation over a range of wavelengths which interact with the indicator molecules 116, i.e., in the case of a fluorescence-based sensor, a wavelength which causes the indicator molecules 116 to fluoresce; and a photodetector 120 (e.g. a photodiode, phototransistor, photoresistor or other photodetector) which, in the case of a fluorescence-based sensor, is sensitive to fluorescent light emitted by the indicator molecules 116 such that a signal is generated by the photodetector 120 in response thereto that is indicative of the level of fluorescence of the indicator molecules. Two photodetectors 120a and 120b are shown to illustrate that sensor 110 may have more than one photodetector. The indicator molecules 116 may be coated on the surface of the sensor body or they may be contained within matrix layer 114 (as shown in FIG. 1), which comprises a biocompatible polymer matrix that is prepared according to methods known in the art and coated on the surface of the sensor housing 112. Suitable biocompatible matrix materials, which must be permeable to the analyte, include some methacrylates (e.g., HEMA) and hydrogels which, advantageously, can be made selectively permeable—particularly to the analyte—i.e., they perform a molecular weight cut-off function. Sensor 110 may be wholly self-contained. In other words, the sensor may be constructed in such a way that no electrical leads extend into or out of the sensor housing 112 to supply power to the sensor (e.g., for driving the source 118) or to transmit signals from the sensor. Rather, the sensor may include a power source 140 that is wholly embedded or housed within the sensor housing 112 and a transmitter 142 that also is entirely embedded or housed within the sensor housing 112. The power source 140 may be an inductor, as may be the antenna for transmitter 142 as described in U.S. Pat. No. 6,400,974. The transmitter 142 may be configured to wirelessly transmit data to an external reader (see FIG. 7). Other self-contained power sources that can be used include microbatteries; piezoelectrics (which generate a voltage when exposed to mechanical energy such as ultrasonic sound; micro generators; acoustically (e.g., ultrasound) driven generators; and photovoltaic cells, which can be powered by light (infrared). As shown in FIG. 1, many of the electro-optical components of sensor 112, including a processor 166, which may include electronic circuitry for controlling, among other components, source 118 and transmitter 142, are secured to a circuit board 170. Circuit board 170 provides communication paths between the components. As further illustrated in FIG. 1, an optical filter 134, such as a high pass or band pass filter, preferably is provided on a light-sensitive surface of a photodetector 120. Filter 134 prevents or substantially reduces the amount of radiation generated by the source 118 from impinging on a photosensitive surface of the photodetector 120. At the same time, the filter allows fluorescent light emitted by fluorescent indicator molecules 116 to pass through to strike a photosensitive region of the detector 120. This significantly reduces “noise” in the photodetector signal that is attributable to incident radiation from the source 118. However, even though filter 134 may significantly reduce “noise” created by radiation from source 118, filter 134 may not significantly attenuate “noise” from ambient light sources 198, particularly because light that passes through skin has a wavelength that may not be filtered by the filter. That is, filter 134 may not significantly prevent ambient light 199 from hitting a photosensitive surface of a photodetector 120. Accordingly, sensor 110 has other features for dealing with the ambient light. For example, substrate 170 of sensor 110 is made of a material that does not propagate stray light or is coated with a finish that prevents it from propagating stray light. Thus, by using such a substrate 170 one can reduce the amount of ambient light reaching the photodetectors 120. In some embodiments, substrate 170 is a ferrite circuit board 170 while in other embodiments substrate 170 may be a conventional circuit board having a finish that prevents the board from propagating light. Additionally, in sensor 110 the photodetectors 120 may be mounted to the underside of circuit board 170. This may be done by, for example, a technique known as “flip-chip” mounting. This technique of mounting the photodetectors 120 to the underside of the board 170 permits all light-sensitive surfaces except the top surface of the photodetectors 120 to be more easily covered with a light blocking substance 104 (e.g., a black, light blocking epoxy). However, it is contemplated that photodetectors 120 can be mounted on the topside of circuit board 170, as shown in FIG. 2. Like in the embodiment shown in FIG. 1, in the embodiment shown in FIG. 2 all surfaces except the top surface of the photodetector are covered with light blocking substance 104. In embodiments where the photodetectors 120 are mounted to the bottom surface of board 170, a hole for each photodetector 120 is preferably created through board 170. This is illustrated in FIG. 3, which is a top view of board 170. As shown in FIG. 3, the light source 118 is preferably mounted to the top surface 371 of board 170. As further shown in FIG. 3, two holes 301a and 301b have been created through board 170, thereby providing a passageway for light from the indicator molecules to reach the photodetectors 120. The holes in circuit board 170 may be created by, for example, drilling and the like. Preferably, each photodetector 120 is positioned such that its face is directly beneath and covering a hole, as shown in FIG. 1. This technique restricts light from entering the photodetectors 120 except from their face and through the hole through the ferrite. As further illustrated in FIG. 1, each hole in the ferrite may be filled with an optical pass filter 134 so that light can only reach a photodetector 120 by passing through the filter 134. As mentioned above and illustrated in FIG. 1, the bottom surface and all sides of the photodetectors 120 may be covered with black light blocking epoxy 104. Additionally, to minimize unwanted reflections that might occur from parts on the top surface 371 of the circuit board 170, a black epoxy may be used as a potting for all components not within the far-field pattern of the optical system. Further, black epoxy may be used to encircle the filters 134 for each photodetector 120, thereby preventing light leakage from propagating through a glue joint created by the mechanical tolerance between the filters 134 and circuit board holes 301. As further shown in FIG. 1, NIR filters 106a and 106b may be positioned on top of filters 134a and 134b, respectively. Such a configuration would require all light reaching a photodetector 120 to pass through not only filter 134, but also NIR filter 106. As FIGS. 1 and 2 make clear, any ambient light that reaches a photodetector 120 must first pass through the matrix 114 containing the indicator molecules and the filters before the light can strike the top surface of the photodetector 120 and, thereby interfere with the optical sensor. Although the matrix 114 is characteristically clear, by increasing the water content of the polymerization reaction, a phase separation occurs which results in a highly porous matrix material 114. The large size of the pores, along with the differential refractive index of the matrix 114 (versus the surrounding medium), cause substantial light scattering within the matrix 114. This scatter is beneficial in helping to attenuate any ambient light arriving from an external source before it can enter the sensor housing. Accordingly, in some embodiments of the invention, the process of making the matrix 114 is altered so that the matrix 114 will be highly porous. For example, in some embodiments, matrix 114 is produced by (a) combining 400 mLs HEMA with 600 mLs distilled water (a 40:60 ratio), (b) swirling to mix, (c) adding 50 uL 10% ammonium persulfate (APS) (aqueous solution) and 10 uL 50% TEMED (aqueous solution), and (d) polymerizing at room temperature 30 minutes to one hour. This process will produce a highly porous matrix (or “white gel” matrix). Polymerization at higher or lower temperatures can also be used to form a white gel matrix. An example is the formation of a 30:70 gel using 175 uL distilled water+75 uL HEMA+8.44 uL VA-044 (2,2′-Azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride)(other free radical initiators such as AIBN (2,2′-Azobisisobutyronitrile) might also be used). Another feature of sensor 110 is that at least part of the housing 112 may be doped with organic or inorganic dopants that will cause the doped part of the housing 112 to function as an optical filter. For example, it is contemplated to dope a part of housing 112 with savinyl black, which is an organic light blocking material. If necessary, under certain propagation vectors of ambient light, it is possible to selectively dope the housing 112 in such a way so as to only permit the region directly within the photodetectors' 120 field of view to propagate light. This mechanism would use a “saddle” graft architecture fabricated by the pre-machined encasement procedure. By use of the non-transparent material 104 and the non-light propagating circuit board 170, the optical field of view of the photodetectors 120 is controlled and restricted to the region of the indicator matrix installation on the surface of the sensor housing 112. The optical field of view for one photodetector 120(a) of the embodiment shown in FIG. 1 is illustrated in FIG. 4. Because light cannot pass through the circuitry from the backside, the sensor 110 can be surgically installed in-vivo so as to orient the optical view of the photodetectors 120 in the most favorable placement to minimize light passing through the skin. For example, in some embodiments, orienting the sensor optical field of view inward toward body core tissue may be most favorable. This is illustrated in FIG. 5. As shown in FIG. 5, the one surface of the photodetector not covered by the non-transparent material 104 (i.e., surface 590) faces inward toward body core tissue 501 and away from the skin 520 to which it is the closest. Because it is possible that this orientation may not be maintained in-vivo following installation (e.g., the sensor might roll during normal limb movement), it is contemplated that in some embodiments it will be advantageous to incorporate anti-roll “outriggers” on the sensor housing 212. FIG. 6 is a front view of sensor 110 with outriggers 610 and 611 attached to sensor housing 212 to prevent rolling. In addition to providing an improved optical sensor design that significantly attenuates the effect of ambient light on the proper functioning of the optical sensor 110, the present invention also provides improvements to the external signal reader that receives the output data transmitted from the optical sensor 110. As discussed above, this output data, which carries information concerning the concentration of the analyte in question, may be transmitted wirelessly from sensor 110. FIG. 7 illustrates an example of an external reader 701. In the embodiment shown in FIG. 7, the optical sensor 110 is implanted near a patient's wrist and the reader 701 is worn like a watch on the patients arm. That is, reader 701 is attached to a wrist band 790. In some embodiments, reader 701 may be combined with a conventional watch. Preferably, wrist band 790 is an opaque wrist band. By wearing an opaque wrist band 790, the patient will reduce the amount of ambient light reaching the optical sensor. As shown in FIG. 7, reader 701 includes a receiver 716, a processor 710, and a user interface 711. The user interface 711 may include a display, such as, for example, a liquid crystal display (LCD) or other type of display. The receiver 716 receives data transmitted from the sensor. The processor 710 may process the received data to produce output data (e.g., a numeric value) that represents the concentration of the analyte being monitored by the sensor. For example, in some embodiments, sensor 110 may transmit two sets of data to reader 701. The first set of data may correspond to the output of the photodetectors 120 when the light source 118 is on and the second set of data may correspond to the output of the photodetectors 120 when the light source 118 is off. Processor 710 processes these two data sets to produce output data that can be used to determine the concentration of the analyte being monitored by the sensor. For instance, the first set of data may be processed to produce a first result corresponding to the sum of (1) the total amount of light from the indicator molecules that reached the photodetectors 120 and (2) the total amount of ambient light that reached the photodetectors 120. The second set of data may be processed to produce a second result corresponding to the total amount of ambient light that reached the photodetectors 120. The processor 710 may then subtract the second result from the first result, thereby obtaining a final result that corresponds to the total amount of light from the indicator molecules that reached the photodetectors 120. The processor 710 may then use the final result to calculate the concentration of the analyte and cause the user interface 711 to display a value representing the concentration so that the patient can read it. Advantageously, reader 701 may include a small photodetector 714. By including photodetector 714 in the reader 701, the reader may monitor the amount of ambient light. Further, the processor can be programmed to output a warning to the patient if the amount of ambient light detected by photodetector 714 is above a pre-determined threshold. For example, if the output of photodetector 714, which may be input into processor 710, indicates that there is a relatively high amount of ambient light, processor 710 may display an alert message on user interface 711 to alert the patient that the sensor may be non-functional due to the high amount of ambient light. The patient can then take the appropriate action. For example, the patient can move to an area where there is less ambient light or shroud the sensor so that less ambient light will reach the sensor. FIG. 8 is a flow chart illustrating a process 800 that may be performed by processor 710. Process 800 may begin in step 802, where processor 710 receives an input indicating that a user of reader 701 has requested to obtain a reading from the sensor or where processor 710 automatically determines that it is time to obtain data from the sensor. In step 804, processor 710 obtains from photodetector 714 information regarding the intensity of the ambient light. In step 806, processor 710 determines, based on the information obtained in step 804, whether the intensity of the ambient light is such that it is likely the sensor will not be able to function properly. For example, processor 710 may determine whether the intensity of the ambient light is greater than some pre-determined threshold. If the intensity of the ambient light is such that it is likely the sensor will not be able to function properly, then processor 710 proceeds to step 890, otherwise processor 710 proceeds to step 808. In step 890, processor 710 issues a warning to the user. For example, processor 710 may display a message on user interface 711 or communicate to the user that there is too much ambient light. In step 808, processor 710 activates the sensor. For example, processor 710 may wirelessly provide power to the sensor, send an activation signal to the sensor, or otherwise activate the sensor. In step 810, processor 710 obtains data from the sensor. For example, as discussed above, the data received from the sensor may include data corresponding to the output of photodetectors 120 when light source 118 is on and data corresponding to the output of photodetectors 120 when light source 118 is off. Sensor 110 may wirelessly transmit the data to receiver 716, which then provides the data to processor 710. In step 812, processor 710 processes the received data to produce a result that, if sensor is operating correctly (e.g., there is not too much ambient light), can be used to calculate the concentration of the analyte being monitored by the sensor. For example, as discussed above, processor 710 may subtract the data corresponding to the output of photodetectors 120 when light source 118 is off from the data corresponding to the output of photodetectors 120 when light source 118 is on to produce a result that can be used to determine the concentration of the analyte being monitored by the sensor. In step 814, processor 710 causes information or a message regarding the analyte being sensed by the sensor to be displayed to the user, wherein the information or message is based on the result produced in step 812. In addition to providing an improved optical sensor design and an improved reader, the present invention provides an improved method for operating an optical sensor, which method also attenuates the negative effect of ambient light. The method may be used with a conventional optical sensor or with optical sensors according to the present invention. FIG. 9 is a flow chart illustrating a process 900 for attenuating the effect of ambient light on readings provided by an optical sensor. Process 900 may begin in step 901, where a determination of the amount of ambient light reaching the photodetector is made. For example, in step 901 a signal produced by one or more photodetectors is obtained during a period of time when the indicator molecules are not in a fluorescent state. In step 902, a determination is made as to whether the amount of ambient light reaching the photodetector is such that it is likely the sensor will not be able to provide an accurate reading. If the amount of ambient light reaching the photodetector is such that it is likely the sensor will not be able to provide an accurate reading, then the process proceeds to step 990, otherwise the process proceeds to step 903. In step 990, information indicating that there is too much ambient light is transmitted to a sensor reader. After step 990, the process may end or proceed back to step 902. In step 903, the indicator molecules are illuminated for about x amount of time (e.g., 50 or 100 milliseconds). For example, in step 903, the light source 118 may be activated for 100 milliseconds to illuminate the indicator molecules. In one embodiment, the light source is activated using about a 2 milliamp drive current. Next, while the indicator molecules are illuminated, the signal produced by a photodetector 120 is read (step 904). Next (step 908), the signal obtained in step 901 is subtracted from the signal obtained in step 904 to produce a new signal, which new signal should better correspond to the concentration of the analyte than the signal read in step 904 because the signal read in step 904 includes not only the light emitted by the indicator molecules but also the ambient light that has reached the photodetector. Next (step 910), the new signal is transmitted to an external reader. After step 910, the process may proceed back to step 901. Process 900 may be performed by processor 266. That is, in some embodiments, processor 266 may have software, hardware or a combination of both for performing one or more steps of process 900. For example, processor 266 may include an application specific integrated circuit (ASIC) that is designed to carry out one or more of the steps of process 900. FIG. 10 is a flow chart illustrating another process 1000 according to an embodiment of the invention. Process 1000 may begin in step 1002 where light source 118 is turned on for about x amount of time (e.g., 50 or 100 milliseconds). For example, in step 1002, the light source 118 may be activated for 100 milliseconds to illuminate the indicator molecules. In step 1004, data corresponding to the outputs produced by photodetectors 120a and 120b while light source 118 is on is transmitted to reader 701. In step 1006, reader 701 receives the data. The data may include a reading from photodetector 120a and a reading from photodetector 120b, which is referred to as the reference photodetector. In step 1008, reader 701 processes the received data to produce a first value. For example, the value may be produced by dividing the reading from photodetector 120a by the reading from photodetector 120b. Next, light source 118 is turned off (step 1010). In step 1012, data corresponding to the outputs produced by photodetectors 120a and 120b while light source 118 is off is transmitted to reader 701. In step 1014, reader 701 receives the data. The data may include a reading from photodetector 120a and a reading from photodetector 120b. In step 1016, reader 701 processes the received data to produce a second value. For example, the second value may be produced by dividing the reading from photodetector 120a by the reading from photodetector 120b. In step 1018, reader 701 subtracts the second value from the first value to obtain a result that can be used to determine the concentration of the analyte being monitored by the sensor. In step 1020, reader 701 displays information concerning the concentration of the analyte (e.g., it displays a value representing the determined concentration). Although the above described processes are illustrated as a sequence of steps, it should be understood by one skilled in the art that at least some of the steps need not be performed in the order shown, and, furthermore, some steps may be omitted and additional steps added. While various embodiments/variations of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to optical sensors, and, more specifically, to a system and method for attenuating the effect of ambient light on an optical sensor. 2. Discussion of the Background An optical sensor is a device that may be used to detect the concentration of an analyte (e.g., oxygen, glucose, or other analyte). U.S. Pat. No. 6,330,464, the disclosure of which is incorporated herein by reference, describes an optical sensor. There may be situations when it is desirable to use an optical sensor in an environment where there is a significant amount of ambient light (e.g., the outdoors on a bright, sunny day). In some circumstances, a significant amount of ambient light may negatively affect the accuracy of an optical sensor. Accordingly, what is desired are systems and methods to attenuate the negative effect of ambient light on the functioning of an optical sensor and/or to measure and compensate quantitatively for the ambient light. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides systems and methods for attenuating the effect of ambient light on optical sensors and for measuring and compensating quantitatively for the ambient light. In one aspect, the present invention provides an optical sensor having features that attenuate the amount of ambient light that reaches the optical sensor's photodetectors. The features can be used together or separately. For example, in some embodiments, the present invention provides an optical sensor wherein the circuit board that is used to electrically connect the electrical components of the sensor is made from an opaque material (e.g., opaque ferrite), as opposed to the conventional aluminum oxide ceramic circuit board. In some embodiments, the photodetectors of the optical sensor are mounted to the bottom side of a circuit board and holes are made in the circuit board to provide a way for light from the indicator molecules to reach the photodetectors. In another aspect, the present invention provides methods for using and implanting an optical sensor, which methods, used together or separately, reduce the effect of ambient light on the optical sensor. For example, in one aspect the present invention provides a method that includes the following steps: illuminating indicator molecules, thereby causing the indicator molecules to emit light; determining the amount of light reaching a photodetector at a point in time when the indicator molecules are illuminated, thereby determining the sum of the amount of ambient light and the light emitted from the indicator molecules reaching the photodetector; ceasing illuminating the indicator molecules; after ceasing illuminating the indicator molecules, determining the amount of light reaching the photodetector, thereby determining the amount of ambient light reaching the photodetector; and determining the amount of light emitted from the indicator molecules that reached the photodetector by subtracting the second determined amount of light from the first determined amount of light. In another aspect, the present invention provides an improved sensor reader and method of operating the sensor reader. For example, in one aspect, the present invention provides a method performed by a sensor reader that includes the steps of: determining the intensity of ambient light; determining whether the intensity of the ambient light is greater than a predetermined threshold intensity; and issuing a warning to the user if it is determined that the intensity of the ambient light is greater than the predetermined threshold intensity. The above and other features and advantages of the present invention, as well as the structure and operation of preferred embodiments of the present invention, are described in detail below with reference to the accompanying drawings. | 20040414 | 20070102 | 20050217 | 75457.0 | 0 | TANINGCO, MARCUS H | SYSTEM AND METHOD FOR ATTENUATING THE EFFECT OF AMBIENT LIGHT ON AN OPTICAL SENSOR | SMALL | 0 | ACCEPTED | 2,004 |
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10,823,868 | ACCEPTED | Method and system of providing sealed bags of fluid at the clean side of a laboratory facility | A method for facilitating the delivery of water to a plurality of cage level barrier-type cages, for housing animals for an animal study, the method including; providing a plurality of cage level barrier-type cages for an animal study at a laboratory facility site, and disposing a bag forming apparatus at a clean side of a laboratory washroom at the laboratory facility site, wherein the bag forming apparatus is capable of providing sealed bags of water for use in the cage level barrier-type cages. The method can further include providing bag material to the laboratory facility site. | 1. A method for facilitating the delivery of water to a plurality of cage level barrier-type cages, for housing animals for an animal study, the method comprising: providing a plurality of cage level barrier-type cages for an animal study at a laboratory facility site; and disposing a bag forming apparatus at a clean side of a laboratory washroom at the laboratory facility site; wherein the bag forming apparatus is capable of providing sealed bags of water for use in the cage level barrier-type cages. 2. The method of claim 1, further comprising providing bag material to the laboratory facility site. 3. The method of claim 2, wherein the bag forming apparatus is capable of forming a tube with the bag material. 4. The method of claim 3, wherein the bag forming apparatus is capable of forming a vertical seal on the tube. 5. The method of claim 4, wherein the bag forming apparatus is capable of adding a quantity of the water to fill the tube. 6. The method of claim 5, wherein the bag forming apparatus is capable of forming a horizontal seal in the tube. 7. The method of claim 6, wherein the bag forming apparatus is capable of cutting the tube at the horizontal seal to form individual bags of fluid. 8. The method of claim 7, wherein the bag forming apparatus is capable of providing additives to the water. 9. The method of claim 8, wherein the bag forming apparatus is capable of heating the water before adding said quantity of water to said tube such that the water and the water bag become sterilized. 10. The method of claim 9, wherein the water is heated to a temperature of about 180° F. 11. The method of claim 1, further comprising providing a disposable fluid valve for use with one of the sealed bags of water. 12. The method of claim 11, wherein the disposable fluid valve is formed of plastic. 13. The method of claim 1, further comprising: providing a disposable fluid delivery valve assembly for use with one of the sealed bags of water, the valve assembly comprising; an upper member having a fluid channel defined therethrough; a base having a flange member and a base fluid channel defined therethrough, wherein the base is designed to be matingly coupled to the upper member; wherein the fluid delivery valve assembly is adapted to be coupled to the fluid bag to facilitate the providing of the water to a cage level barrier-type cage. 14. A method for facilitating the delivery of water to a plurality of cage level barrier-type cages disposed at a laboratory facility site, for housing animals for an animal study, the method comprising: disposing a bag forming apparatus at a clean side of a laboratory washroom at the laboratory facility site; wherein the bag forming apparatus is capable of providing sealed bags of water for use in the cage level barrier-type cages. 15. The method of claim 14, further comprising providing bag material to the laboratory facility site. 16. The method of claim 14, further comprising providing a disposable fluid valve for use with one of the sealed bags of water. 17. The method of claim 16, wherein the disposable fluid valve is formed of plastic. 18. The method of claim 14, further comprising providing a ventilated rack and cage system comprising a plurality of cage level barrier-type cages for placement at the laboratory facility site. 19. The method of claim 15, the bag material being provided in rolls, the method further comprising providing a lift apparatus for handling the rolls of bag material. 20. The method of claim 14, further comprising providing a conveyor system at the clean side of the laboratory washroom at the laboratory facility site for transporting the sealed water bags. 21. The method of claim 14, further comprising providing one or more totes for storing and transporting the sealed water bags. 22. The method of claim 21, further comprising providing a tote cart for transporting a plurality of the totes from the clean side of the washroom to a laboratory room containing the cage level barrier-type cages. 23. The method of claim 22, further comprising providing a tote conveyor platform for transporting the totes with sealed water bags from the conveyor system to the tote cart. 24. The method of claim 14, further comprising providing a compacting apparatus for compacting the sealed water bags after they are removed from the cage level barrier-type cages. 25. A method for eliminating the use of water bottles at an animal laboratory facility having a plurality of cage level barrier-type cages disposed at a laboratory facility site, for housing animals for an animal study, the method comprising: disposing a bag forming apparatus at a clean side of a laboratory washroom at the laboratory facility site; wherein the bag forming apparatus is capable of providing sealed bags of water for use in the cage level barrier-type cages. 26. The method of claim 25, further comprising providing bag material to the laboratory facility site. 27. The method of claim 25, further comprising providing a disposable fluid valve for use with one of the sealed bags of water bags. 28. The method of claim 27, wherein the disposable fluid valve is formed of plastic. 29. The method of claim 25, further comprising providing a ventilated rack and cage system comprising a plurality of cage level barrier-type cages for placement at the laboratory facility site. 30. The method of claim 26, the bag material being provided in rolls, the method further comprising providing a lift apparatus for handling the rolls of bag material. 31. The method of claim 25, further comprising providing a conveyor system at the clean side of the laboratory washroom at the laboratory facility site for transporting the sealed water bags. 32. The method of claim 25, further comprising providing one or more totes for storing and transporting the sealed water bags. 33. The method of claim 32, further comprising providing a tote cart for transporting a plurality of the totes from the clean side of the washroom to a laboratory room containing the cage level barrier-type cages. 34. The method of claim 33, further comprising providing a tote conveyor platform for transporting the totes with sealed water bags from the conveyor system to the tote cart. 35. The method of claim 25, further comprising providing a compacting apparatus for compacting the sealed water bags after they are removed from the cage level barrier-type cages. 36. A system for facilitating the delivery of water to a plurality of cage level barrier-type cages disposed at a laboratory facility site, for housing animals for an animal study, the system comprising: a bag forming apparatus designed and configured for placement at a clean side of a laboratory washroom at the laboratory facility site; wherein the bag forming apparatus is capable of providing sealed bags of water for use in the cage level barrier-type cages. 37. The system of claim 36, further comprising bag material that is provided to the laboratory facility site. 38. The system of claim 36, further comprising a disposable fluid valve provided at the laboratory facility site for use with one of the sealed bags of water. 39. The system of claim 38, wherein the disposable fluid valve is formed of plastic. 40. The system of claim 36, further comprising a ventilated rack and cage system comprising a plurality of cage level barrier-type cages for placement at the laboratory facility site. 41. The system of claim 37, further comprising a lift apparatus for handling rolls of the provided bag material. 42. The system of claim 36, further comprising a conveyor system for placement at the clean side of the laboratory washroom at the laboratory facility site for transporting the sealed water bags. 43. The system of claim 36, further comprising one or more totes for storing and transporting the sealed water bags. 44. The system of claim 43, further comprising a tote cart for transporting a plurality of the totes from the clean side of the washroom to a laboratory room containing the cage level barrier-type cages. 45. The method of claim 44, further comprising providing a tote conveyor platform for transporting the sealed water bags from the conveyor system to the tote cart. 46. The system of claim 36, further comprising a compacting apparatus for compacting the sealed water bags after they are removed from the cage level barrier-type cages. | CROSS-REFERENCE TO RELATED APPLICATIONS This application is a Continuation-In-Part of U.S. patent application Ser. No. 10/274,619, filed on Oct. 21, 2002, and entitled Fluid Deliver System, currently pending, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/346,218, filed on Oct. 19, 2001, the contents of both applications being hereby incorporated by reference herein. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to fluid delivery systems and in particular to a fluid delivery system and method for caging or storage systems for animals. 2. Description of Related Art A large number of laboratory animals are used every year in experimental research. These animals range in size from mice to non-human primates. To conduct valid and reliable experiments, researchers must be assured that their animals are protected from pathogens and microbial contaminants that will affect test results and conclusions. Proper housing and management of animal facilities are essential to animal well-being, to the quality of research data and teaching or testing programs in which animals are used, and to the health and safety of personnel. Ordinarily, animals should have access to potable, uncontaminated drinking water or other needed nutrient containing fluids according to their particular requirements. Water quality and the definition of potable water can vary with locality. Periodic monitoring for pH, hardness, and microbial or chemical contamination might be necessary to ensure that water quality is acceptable, particularly for use in studies in which normal components of water in a given locality can influence the results obtained. Water can be treated or purified to minimize or eliminate contamination when protocols require highly purified water. The selection of water treatments should be carefully considered because many forms of water treatment have the potential to cause physiologic alterations, changes in microflora, or effects on experimental results. For example, chlorination of the water supply can be useful for some species but toxic to others. Because the conditions of housing and husbandry affect animal and occupational health and safety as well as data variability, and effect an animal's well-being, the present invention relates to providing a non-contaminated, replaceable, disposable source of fluid for laboratory animals in a cage level barrier-type cage or integrated cage and rack system to permit optimum environmental conditions and animal comfort. Animal suppliers around the world have experienced an unprecedented demand for defined pathogen-free animals, and are now committed to the production and accessibility of such animals to researchers. Likewise, laboratory animal cage manufacturers have developed many caging systems that provide techniques and equipment to insure a pathogen free environment. For example, ventilated cage and rack systems are well known in the art. One such ventilated cage and rack system is disclosed in U.S. Pat. No. 4,989,545, the contents of which are incorporated herein by reference, assigned to Lab Products, Inc., in which an open rack system including a plurality of shelves, each formed as an air plenum, is provided. A ventilation system is connected to the rack system for ventilating each cage in the rack, and the animals therein, thereby eliminating the need for a cage that may be easily contaminated with pathogens, allergens, unwanted pheromones, or other hazardous fumes. It is known to house rats, for example, for study in such a ventilated cage and rack system. The increasing need for improvement and technological advancement for efficiently, safely housing and maintaining laboratory animals arises mainly from contemporary interests in creating a pathogen-free laboratory animal environment and through the use of immuno-compromised, immuno-deficient, transgenic and induced mutant (“knockout”) animals. Transgenic technologies, which are rapidly expanding, provide most of the animal populations for modeling molecular biology applications. Transgenic animals account for the continuous success of modeling mice and rats for human diseases, models of disease treatment and prevention and by advances in knowledge concerning developmental genetics. Also, the development of new immuno-deficient models has seen tremendous advances in recent years due to the creation of gene-targeted models using knockout technology. Thus, the desire for an uncontaminated cage environment and the increasing use of immuno-compromised animals (i.e., SCID mice) has greatly increased the need for pathogen free sources of food and water. One of the chief means through which pathogens can be introduced into an otherwise isolated animal caging environment is through the contaminated food or water sources provided to the animal(s). Accordingly, the need exists to improve and better maintain the health of research animals through improving both specialized caging equipment and the water delivery apparatus for a given cage. Related caging system technologies for water or fluid delivery have certain deficiencies such as risks of contamination, bio-containment requirements, DNA hazardous issues, gene transfer technologies disease induction, allergen exposure in the workplace and animal welfare issues. Presently, laboratories or other facilities provide fluid to their animals in bottles or other containers that must be removed from the cage, disassembled, cleaned, sterilized, reassembled, and placed back in the cage. Additionally, a large quantity of fluid bottles or containers must be stored by the labs based on the possible future needs of the lab, and/or differing requirements based on the types of animals studied. This massive storage, cleaning and sterilization effort, typically performed on a weekly basis, requires large amounts of time, space and human resources to perform these repetitive, and often tedious tasks. Further, glass bottles (and the handling thereof) can be dangerous and also relatively costly. Bottle washing machines, bottle fillers, wasted water, hot water, wire baskets to hold bottles, sipper tubes, rubber stoppers, the ergonomic concerns of removing stoppers, screw caps insertion of sipper tubes are all problems inherent to the use of water bottles to provide water to animals. Although automatic watering systems are available the cost per cage is too costly for many institutions. Stainless steel valves and manifolds need constant purging of slime and buildup of mineral deposits. The human factors of handling wire baskets while loading and unloading bottles has led to industry wide back injuries, carpel wrist injury, and eye injury from broken glass and other human factor ergonomic risks. By some estimates, the cost of injury related costs to industry and the lost productivity in the workplace amount to millions of dollars annually. In addition, the use of water bottles typically leads to large energy costs because the cleaning of the water bottles typically requires hot water heated to approximately 180 degrees F. and the washing of all of the components of the water bottles and caps with dangerous chemicals. As such, a need exists for an improved system for delivering fluid to laboratory animals living in cage level barrier-type rack and cage systems. SUMMARY OF THE INVENTION The present invention satisfies this and other needs. Briefly stated, in accordance with an embodiment of the invention, a fluid delivery system for delivering a fluid to an animal caging system for housing an animal is described. The fluid delivery system may comprise a fluid delivery valve assembly adapted to be coupled to a fluid bag holding a fluid. By advantageously using sanitized fluid bags, that may be disposable, the invention may minimize the need for the use of fluid bottles that typically must be removed from cages, cleaned, and sanitized on a frequent basis. The delivery system may be utilized in a single cage or in multiples cages integrated into ventilated cage and rack systems known in the art. An embodiment of the invention described herein provides for a fluid delivery system for delivering a fluid from a fluid bag to an animal caging system for housing an animal and may comprise a fluid delivery valve assembly, wherein the fluid delivery valve assembly is adapted to be coupled to the fluid bag to facilitate the providing of the fluid to an animal in the caging system. The fluid delivery valve assembly may further comprise an upper member having a piercing member and a connecting member, the upper member having a fluid channel defined therethrough, a base having a flange member and a base fluid channel defined therethrough, wherein the base is designed to be matingly coupled to the upper member. The fluid delivery valve assembly may further comprise a spring element disposed within the base fluid channel and a stem member disposed in part within the base fluid channel, wherein a portion of the spring element abuts the stem member to apply a biasing force. Another embodiment of the invention may provide for a method for delivering fluid to one or more animal cages comprising providing sealed sanitized bags of fluid for use in an animal cage or caging system. The method may further comprise providing bag material to be used in the formation of fluid bags. Another embodiment is directed to a method for facilitating the delivery of water to a plurality of cage level barrier-type cages, for housing animals for an animal study. The method comprises providing a plurality of cage level barrier-type cages for an animal study at a laboratory facility site, and disposing a bag forming apparatus at a clean side of a laboratory washroom at the laboratory facility site. The bag forming apparatus is capable of providing sealed bags of water for use in the cage level barrier-type cages. In addition, the method can further comprise providing bag material to the laboratory facility site. Another embodiment of the invention involves a method for facilitating the delivery of water to a plurality of cage level barrier-type cages disposed at a laboratory facility site, for housing animals for an animal study. The method comprises disposing a bag forming apparatus at a clean side of a laboratory washroom at the laboratory facility site; wherein the bag forming apparatus is capable of providing sealed bags of water for use in the cage level barrier-type cages. Another embodiment of the invention is directed to a system for facilitating the delivery of water to a plurality of cage level barrier-type cages disposed at a laboratory facility site, for housing animals for an animal study. The system comprises a bag forming apparatus designed and configured for placement at a clean side of a laboratory washroom at the laboratory facility site, wherein the bag forming apparatus is capable of providing sealed bags of water for use in the cage level barrier-type cages. Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification. Other features and advantages of this invention will become apparent in the following detailed description of exemplary embodiments of this invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS In the drawing figures, which are merely illustrative, and wherein like reference characters denote similar elements throughout the several views: FIG. 1 is an exploded perspective view of a fluid delivery system incorporated into an animal cage assembly; FIG. 2 is an exploded perspective view of a fluid delivery system and diet delivery system in accordance with the present invention; FIG. 3 is an exploded perspective view of an embodiment of a fluid delivery valve assembly in accordance with the present invention; FIG. 4 is a side view of the fluid delivery valve assembly of FIG. 3; FIG. 5 is a side cutaway view of the upper member of the fluid delivery valve assembly of FIG. 3; FIG. 6 is a perspective view of trigger assembly of a fluid delivery valve assembly in accordance with the present invention; FIG. 7 is a top plain view of cup element in accordance with the present invention; FIG. 8 is a perspective view of the cup element in accordance with the present invention; FIG. 9 is a cutaway view of cup element in accordance with the present invention; FIG. 10 is a perspective view of a diet delivery system; FIG. 11 is a top plan view of diet delivery system incorporating a fluid delivery system in accordance with the present invention; FIG. 12 is a front cutaway view of diet delivery system; FIG. 13 is a bottom view of a fluid bag in accordance with the present invention; FIG. 14 is a perspective view of a fluid bag and a fluid diet component with a fluid delivery system in accordance with the present invention; FIG. 15 is a cutaway view of a fluid bag in accordance with the present invention; FIG. 16 is a side perspective view of an upper member of a fluid delivery valve assembly including a support in accordance with the present invention; FIG. 17 is a plain side view of a double-sided rack system incorporating an animal cage; FIG. 18 is an exploded perspective view of an embodiment of a fluid delivery valve assembly in accordance with the present invention; FIG. 19 is a side cutaway view of the fluid delivery valve assembly of FIG. 18; FIG. 20 is a perspective view of the stem of the fluid delivery valve assembly of FIG. 18; FIG. 21 is a side cutaway view of the fluid delivery valve assembly of FIG. 18, showing the stem in the sealed position; FIG. 22 is a side cutaway view of the fluid delivery valve assembly of FIG. 18, showing the stem in the opened position; FIG. 23 is a side cutaway view of the fluid delivery valve assembly of FIG. 18, showing the extension portion protecting the stem; FIG. 24 is a side cutaway view of an upper member of a fluid delivery valve assembly including a wrapper in accordance with the present invention; FIG. 25 is a side cutaway view of an upper member of a fluid delivery valve assembly including a disposable cap in accordance with the present invention; FIG. 26 is a fluid bag filling and sealing device in accordance with the present invention; FIG. 27 is a view of a fluid bag preparation room in accordance with the present invention; FIG. 28 is another view of a fluid bag preparation room in accordance with the present invention; FIG. 29 is another view of a fluid bag preparation room in accordance with the present invention; FIG. 30 is a schematic diagram of equipment used in certain embodiments; FIG. 31 is a schematic plan view of a laboratory facility illustrating a flow pattern and placement of a bag forming and filling apparatus; FIG. 32 is a schematic plan view of a laboratory facility illustrating another flow pattern and placement of a bag forming and filling apparatus; FIG. 33 is flow diagram illustrating an exemplary process in accordance with certain embodiments; and FIG. 34 is another flow diagram illustrating another exemplary process in accordance with certain embodiments. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Reference is made to FIGS. 1 and 2, wherein an animal cage assembly 90, which incorporates fluid delivery valve assembly 1, is shown. Cage assembly 90 incorporates a filter retainer 91, a filter frame 92, a filter top lock 93, a chew shield 94, a plurality of snap rivets 95, a fluid bag 60 containing fluid 70, a fluid delivery valve assembly 1, a diet delivery system 96 providing support member 50, a chow receptacle 111, a fluid bag receptacle 110, and a cage body 98. Cage body 98 comprises a box-like animal cage with a combination diet delivery system 96 capable of providing both food and fluid to animals within cage assembly 90. A filter 99 is also generally provided with cage assembly 90 sandwiched between filter retainer 91 and filter frame 92. Cage body 98 is formed with integral side walls 100, a bottom wall or floor 101 and an open top end. The open top of cage body 98 is bordered by peripheral lip 102, which extends continuously there around. Cage body 98 may also include a plurality of corner stacking tabs 103 for facilitating stacking and nesting of a plurality of cage bodies 98. Reference is made to FIGS. 3-5 wherein fluid delivery valve assembly 1 is depicted. Fluid delivery valve assembly 1 includes an upper member 10, a spring element 20, a trigger assembly 30, and a cup element 40 for use in animal cage 90. Water delivery system 1 is held in place in animal cage 90 by support element 50. Support element 50 extends from diet delivery system 96 and forms a floor for fluid bag receptacle 110. Alternatively, water delivery system 1 may be molded into diet delivery system 96. As shown in FIGS. 4 and 5, upper member 10 includes piercing member 11, core member 12 and flange member 13. Upper member 10 also defines fluid channel 14. Arrow “A” defines the flow of fluid through fluid delivery valve assembly 1 to trigger assembly 30 where fluid flow can be actuated by an animal in animal cage 90. Piercing member 11 has a beveled tip 15 at its upper end, the upper edge of which presents a sharp piercing edge 16 that can come in contact and pierce fluid bag 60, releasing fluid 70 in fluid bag 60 through fluid channel 14. Flange member 13 extends from core member 12. In a preferred embodiment, flange member 13 is circular in dimension. However, it will be readily understood by one of ordinary skill in the art that flange member 13 may be any shape desired, provided however, that at least a portion of flange member 13 is wider in diameter than fluid channel 14 of core member 12. As shown in FIG. 3, spring element 20 may be a tightly wound coiled member which rests atop tip 35 of upper end 33 of stem 31 and enters upper member 10 through fluid channel 14. As shown in FIG. 5, fluid channel 14 is dimensioned such that its upper extent within piercing member 11 is narrowed at position 17 such that it prevents spring element 20 from exiting fluid channel 14 through piercing member 11. Reference is made to FIG. 6, wherein trigger assembly 30 is depicted. Trigger assembly 30 includes a stem 31, inserted through sealing member 32. Stem 31 having an upper end 33 and a lower end 36. Lower end 36 of stem 31 is substantially flat. Upper end 33 of stem 31 is generally conical in shape, although other shapes may be used. Sealing member 32 fits tightly around stem 31 thereby allowing limited movement around stem 31. Sealing member 32 is dimensioned such that the base of the conical portion of upper end 33 rests on it. Sealing member 32 is formed of a resilient material, such as rubber, silicone rubber, or any other pliant malleable material. In a preferred embodiment, sealing member 32 is made of a material that is not deleterious to mammals. Cup element 40 is depicted in FIGS. 7-9. Cup element 40 has a base 43, an inner surface 41, and an outer surface 42. Base 43 also defines actuation channel 400. Lower end 36 of stem 31 of trigger assembly 30 extends through actuation channel 400 towards the interior of animal cage 90. Fluid channel 14 extends from piercing edge 16 through piercing member 11, core member 12 and spring element 20. Fluid channel 14 terminates at the bottom wall of cup element 40. Trigger assembly 30 extends through actuation channel 400. Cup element 40 has friction fit with core member 12 of upper member 10 directly below flange member 13. Diet delivery system 96, which houses fluid bag receptacle 110 and chow receptacle 111 is shown in FIGS. 10-12. As shown in FIG. 11, fluid bag receptacle 110 holds fluid bag 60 containing fluid 70. Fluid delivery valve assembly 1 is held securely in receptacle base 112 of fluid bag receptacle 110 by the interconnection between flange members 13a, 13b, 13c and 13d and locking members 51a, 51b, 51c and 51d. Piercing edge 16 of fluid delivery valve assembly 1 punctures fluid bag 60. As shown in FIGS. 11 and 12, chow receptacle 111 of diet delivery system 96 holds wire food holder element 116. A further embodiment of the present invention in shown in FIGS. 10 and 12, wherein fluid bag receptacle 110 may be molded 110′ in order to facilitate the emptying of fluid 70 contained in fluid bag 60 by fluid delivery valve assembly 1 and to prevent the animal from gaining purchase on the fluid bag receptacle. In an alternate embodiment, fluid bag 60 is tapered or dimensioned so as to facilitate the emptying of fluid bag 60 by fluid delivery valve assembly 1. Fluid bag 60 may be made replaceable or disposable and thus may be manufactured singly in any quantity according to the needs of a user. Fluid delivery valve assembly 1 may be used to deliver the contents of fluid bag 60 to an animal in cage assembly 90. Fluid 70 in fluid bag 60 may include water, distilled water, water supplemented with various vitamins, minerals, medications such as antibiotics or anti-fungal agents, and/or other nutrients, or any fluid which is ingestible by a caged animal. Fluid 70 in fluid bag 60 is delivered to an animal in cage assembly 90 in a sterilized or sanitized condition so as to protect any animals in cage assembly 90 from contagion. Fluid bag 60 may be formed in any desirable shape or volume. In a preferred embodiment, fluid bag 60 is formed to fit fluid bag receptacle 110. Also, it should be clear that fluid bag 60 does not have to consist of a flexible material but that part thereof may be made of a rigid material. In an embodiment of the present invention, fluid bag 60 would consist of one or more layers, which would tear upon insertion of piercing member 11. Alternatively, flexible, stretchable, resilient plastic stickers 501 may be provided which can be adhered to the bag to prevent tearing thereof and to form a seal about the inserted piercing member 1 1. In addition, as depicted in FIGS. 13-15, fluid bag 60 could be made of a thinner plastic or inverted in the region where piercing edge 16 will penetrate fluid bag 60, thereby allowing the end user to readily identify where fluid bag 60 should be punctured and helping fluid bag 60 nest within fluid bag receptacle 110. In a further embodiment of the present invention, fluid bag 60 could be made of a resilient plastic or polymer material such that when piercing edge 16 penetrates fluid bag 60 at location 88, fluid bag 60 adheres to piercing member 16 so as to stop fluid 70 from leaking out of fluid bag 60. Fluid bag 60 may be constructed out of any material which is capable of being punctured by piercing member 16 and which is capable of holding fluid in a sterilized condition. In an embodiment of the invention, fluid bag 60 is plastic or any other flexible material capable of containing a fluid to be delivered to one or more laboratory animals. In certain embodiments, fluid bag 60 may be formed of nylon or polyethylene film in a single layer or multilayer design. With use of a multilayer film, different layers can each have different properties. For example, the inner layers could provide sealing properties, while the outer layers provide resistance to tearing, or vice versa. In a further embodiment of the present invention, fluid delivery valve assembly 1, upper member 10, fluid bag 60 and the contents thereof, fluid 70, are capable of being sterilized by one or more of an assortment of different means including but not being limited to: ultraviolet light, irradiation, chemical treatment, reverse osmosis, gas sterilization, steam sterilization, filtration, autoclave, and/or distillation. Each of the elements of the current invention, fluid delivery valve assembly 1, fluid bag 60 and fluid 70, can be sterilized or sanitized alone or in combination with each other. Fluid 70 of fluid bag 60 may be sterilized either before or after fluid bag 60 is sealed. In one embodiment providing a method of sterilization for the contents of fluid bag 60, a chemical compound capable of sterilizing the fluid 70, and known in the art, is put inside fluid bag 60 with fluid 70 prior to fluid bag 60 being sealed. Thereafter the compound sterilizes fluid 70 such that it can be delivered to an animal and consumed by that animal without harm. Other methods of sterilization are discussed below. In an embodiment of the invention, leak preventing member 501 is affixed or formed to upper member 10 and prevents a loss of fluid 70 from fluid bag 60 after puncture by piercing member 11. As shown in FIG. 14, piercing member 11 may be rigidly fixed to support element 50 of fluid bag receptacle 110 (see FIGS. 1 and 4), in particular in the support for the bag having its point directed upwards so that piercing member 11 is automatically inserted into fluid bag 60 at location 88 when placing fluid bag 60 onto support element 50 or into fluid bag receptacle 110′. In one embodiment of the present invention, fluid bag 60 is placed in fluid bag receptacle 110 of animal cage 90. Fluid bag receptacle 110 has a base 112, an inner surface 114 and an outer surface 115. Receptacle base 112 also defines actuation channel 400. When fluid delivery valve assembly 1 is used in conjunction with animal cage 90, stem 31 of trigger assembly 30 extends through cup 40 towards the interior of animal cage 90. In another embodiment, that portion of receptacle base 112 which encircles actuation channel 400 may include one or more locking members 51. As shown in FIG. 16, in an alternate embodiment, support member 50 may have four (or some other number of) locking members 51a, 51b, 51c and 51d formed thereon which may be used to secure flange members 13a, 13b, 13c and 13d to support member 50. It will be readily understood by one of ordinary skill in the art that flange members 13a, 13b, 13c and 13d may vary in shape, provided however, that flange members 13a, 13b, 13c and 13d are secured in fluid receptacle base 112 or onto support member 50 by its locking members 51a, 51b, 51c and 51d. In FIG. 16, locking members 51a, 51b, 51c and 51d are shaped like fingers and flange member 13 is divided into four equal pieces, shown as flange members 13a, 13b (not shown), 13c and 13d. Referring now to FIG. 17, an animal isolation and caging rack system 600 of the invention includes an open rack 615 having a left side wall 625 and a right side wall 630, a plurality of rack coupling stations 616, a top 635, and a bottom 640. A plurality of posts 645 are disposed in parallel between top 635 and bottom 640. Vertical posts 645 are preferably narrow and may comprise walls extending substantially from the front of rack 615 to the rear of rack 615, or may each comprise two vertical members, one at or near the front of rack 615 and the other at or near the rear of rack 615. Animal isolation and caging rack system 600 also includes a plurality of air supply plena 610 and air exhaust plena 620 alternately disposed in parallel between left side wall 625 and right side wall 630 in rack 615. The above discussed fluid delivery valve assembly 1, while facilitating the providing of fluid to animals, was found to have some deficiencies when used in conjunction with certain rack and cage system configurations. For example, with reference back to FIG. 3, when the stem 31 of the trigger assembly 30 is actuated by an animal, under certain circumstances, the stem may remain stuck in the open position even after the animal discontinues actuating the stem 31. If the stem remains stuck in the open position, fluid may continue to leak into the cage and cage bedding, with the result being a waste of fluid, and the potential for the animal to become hypothermic, or otherwise adversely affected. One reason for the occurrence of this problem in certain circumstances may be that due to the specific arrangement of the stem 31, sealing member 32 and spring element 20 within the fluid channel 14, when the stem 31 is actuated by an animal, the pivot point of upper end 33 of stem 31 about the bottom of spring element 20 tends not to be either predictable or consistent. Consequently, after actuation by an animal, stem 31, in certain circumstances, will shift position in relation to spring element 20, thus not allowing spring element 20 to bias stem 31 back into the desired closed position. With reference to FIG. 18, there is shown a fluid delivery valve assembly 200 that overcomes the above-discussed deficiency because, among other modifications, the arrangement of stem member 240, spring member 250, and sealing member 260 is different than that of their respective corresponding parts in fluid delivery valve assembly 1. This arrangement of stem member 240, spring member 250, and sealing member 260, discussed in detail below, provides for a predictable and consistent pivot point for stem member 240, thus facilitating a more consistent return to the closed position in the absence of actuation by an animal. Thus, fluid delivery valve assembly 200 is different in structure and arrangement to that of fluid delivery valve assembly 1 in several respects. However, in accordance with the present invention, fluid delivery valve assembly 200 may be used in all embodiments discussed above with reference to fluid delivery valve assembly 1. Accordingly, in any embodiment described herein that describes the use of fluid delivery valve assembly 1 in conjunction with, by way of non-limiting example, fluid bag 60, animal isolation and caging rack system 600, and/or diet delivery system 96, fluid delivery valve assembly 200 may be used as well, in accordance with the invention. With reference again to FIG. 18, there is shown fluid delivery valve assembly 200 having an upper member 210, and a base 220. Fluid delivery valve assembly 200 also includes sealing member 260, stem member 240, and spring member 250. Upper member 210 is formed with generally conical piercing member 211 having sharp point 214 for piercing fluid bag 60 as described above. One or more fluid apertures 215 are defined in a portion of piercing member 210, to facilitate the flow of fluid 70 from bag 60 into a fluid channel 216 defined within the piercing member 210. Upper member 210 is also formed with connecting member 212, having gripping portion 213 encircling a portion thereof. In certain embodiments, stem member 240, base 220 and upper member 210 are formed of plastic, such as polypropylene. In certain embodiments, sealing member 260 is formed of silicone rubber, and spring member 250 is formed from stainless steel. Fluid delivery valve assembly 200 is, in certain embodiments, relatively low in cost, and disposable. Base 220, being generally cylindrical in shape, includes top portion 221 and bottom portion 222, which are separated by flange member 226 which encircles base 220 and extends outwardly therefrom. Flange member 226 may be used to facilitate mounting or positioning of fluid delivery valve assembly 200 as is described above with regard to fluid delivery valve assembly 1. Top portion 221 may have an inner surface 223 with gripping portion 213 disposed thereon. Upper member 210 is designed and dimensioned to be coupled to base 220 with connecting member 212 being inserted into base top portion 221. The coupling may be facilitated by the frictional interaction of gripping portion 213 of upper member 210 with gripping portion 224 of base 220. Sealing member 260, stem member 240, and spring member 250 are disposed within base fluid channel 230. Stem member 240 has a top portion 241 that may be generally flat, such that flow aperture 265 of sealing member 260 may be advantageously sealed when a portion of bottom surface 262 of sealing member 260 is contacted by top surface 243 of stem member 240. Actuation portion 242 of stem member 240 extends through spring member 250 and through base fluid channel 230. Spring member 250 serves to bias stem member 240 against sealing member 260 to facilitate control of the flow of fluid, as described above with respect to fluid delivery valve assembly 1. With reference to FIG. 19, spring member 250 is retained within base fluid channel 230 at its bottom end as fluid channel 230 has narrow portion 232, which serves to block spring member 250 from passing through and out of fluid channel 230. The top of spring member 250 abuts the lower surface 244 (see FIG. 20) of stem member 240. Spring member 250 serves to bias stem member 240 in a vertical orientation, thus forming a seal between top surface 243 and sealing member 260. This seal may be facilitated by the use of lower ridge 266 to concentrate the biasing force of spring member 250 to form a seal against stem member 240. Turning to FIGS. 21 and 22, there is shown the operation of fluid delivery valve assembly 200 when stem member 240 is actuated by an animal. It should be noted that spring member 250 is not shown in FIGS. 21 and 22 for sake of clarity. During actuation of stem member 240 by an animal, however, as discussed above, spring member 250 provides a biasing force to bias stem member 240 toward a generally vertical position. With reference to FIG. 21, stem member 240 is positioned generally vertically, with top surface 243 of stem member 240 advantageously abutting lower ridge 266 of sealing member 260 at sealing point 246. The use of lower ridge 266 in conjunction with top surface 240 advantageously serves to focus and concentrate the biasing force of spring member 250 to form a seal as discussed above. Fluid delivery system 200 is shown having been punctured into fluid bag 60 such that fluid 70 may flow from fluid bag 60 into fluid aperture 215 of upper member 210, and in turn flow into fluid channel 216, through flow aperture 265 of sealing member 260, down to sealing point 246. At this point, with stem member 240 in the vertical (sealed) position, flow of the fluid is stopped. In an embodiment of the invention, bag 60, once punctured by fluid delivery valve assembly 200, should have its outer wall positioned in the range along surface 235 of top portion 201 of base 220 such that it remains disposed in the portion delimited at its upper bounds by bag retention wall 217 and at its lower bounds by flange top surface 227. In an embodiment of the invention, flow aperture 215 and (in some embodiments) aperture portion 218 may be advantageously positioned about an edge of bag retention wall 217. Turning now to FIG. 22, there is shown stem member 240 positioned as it would be while an animal actuates actuation portion 242 of stem member 240 in a direction B. Of course, one skilled in the art would recognize that the same result would be achieved so long as the stem member is actuated outwardly, out of its resting vertical position. Upon actuation in direction B, stem member 240 pivots about pivot point 236 such that top surface 243 of stem member 240 moves away from the lower ridge 266 of sealing member 260. This movement allows fluid 70 at flow aperture 265 of sealing member 260 to flow down through gap 237, into fluid channel 230, and out to the animal in the general direction A. Base 220 may be formed with abutment wall 233 disposed in fluid channel 230 such that the maximum travel of stem member 240 is limited such that the flow of fluid 70 is advantageously limited to a desired value. Additionally, stem member 240, base 220, sealing member 250 and spring member 250 may be advantageously designed and dimensioned such that stem member 240 pivots at a consistent and predictable pivot point 236 and will thus not be subject to sticking or jamming in the open position after stem member 240 is released from actuation by the animal. Consequently, the wasting of fluid and the exposure of animals to hypothermia or other problems caused by excessive wetting of the cage and bedding material may be minimized. Turning to FIG. 23, embodiments of the invention may be formed with base 220 of fluid delivery valve assembly 200 having extension portion 234. Extension portion 234 may serve, in certain application specific scenarios, to protect the actuation portion 242 of stem member 240 from being accidentally bumped by an animal, as only a portion of actuation portion 242 extends beyond extension portion 234. In an embodiment of the invention, the relative lengths L1 and L2 of extension portion 234 and actuation portion 242 may be adjusted based on the results desired, and the types of animals being fed, as well as other factors. Referring to FIG. 24, in an embodiment of the current invention water delivery system 1 (or fluid delivery valve assembly 200) is sterilized and/or autoclaved and maintained in a sterilized state prior to use in a wrapper 47 or other suitable container so as to avoid infecting an animal in animal cage 90 (while, for sake of brevity, the embodiments of the invention discussed below make specific reference only to fluid delivery valve assembly 1, it is to be understood that fluid delivery valve assembly 200 may also be used in all instances as well). When a user determines that a clean water delivery system is needed in conjunction with a fluid bag 60, water delivery system 1 is removed from wrapper 47 in sterile conditions or utilizing non-contaminating methods and inserted into animal cage 90 in fluid bag receptacle 110 (while it is contemplated that all of fluid delivery valve assembly 1 would be contained within wrapper 47, only a portion of fluid delivery valve assembly 1 is illustrated in FIG. 24). Thereafter fluid bag 60 is placed in fluid bag receptacle 110 and is punctured by piercing member 11 such that fluid 70 (i.e., water) is released through fluid channel 14 to an animal in animal cage 90. This procedure insures that sterilized fluid 70 is delivered through an uncontaminated fluid channel and that fluid delivery valve assembly 1 is itself uncontaminated and pathogen free. Additionally, in an embodiment of the invention, fluid delivery valve assembly 1 may be sold and stored in blister packs in groups of various quantities. Referring to FIG. 25, in another embodiment of the invention the upper portion of fluid delivery valve assembly 1, including upper member 10 and piercing member 11, is covered with a disposable cap 45, that can be removed when a user wants to use water delivery system 1 to pierce fluid bag 60 and place it in fluid bag receptacle 110 for delivery of a fluid to an animal in animal cage 90. Disposable cap 45 can be made from any suitable material and may be clear, color-coded to indicate the type of fluid in fluid bag 60, clear or opaque. Disposable cap 45 is easily removed from fluid delivery valve assembly 1. While cap 45 would not provide for a sterilized fluid delivery valve assembly 1, it would provide a labeling function, as well as, in an embodiment, provide protection from inadvertent stabbing of a user. An embodiment of the present invention provides a system and method for fluid delivery to one or more animal cages. The system provided has at least two methods of use, one which includes providing sealed sanitized bags of fluid for use in an animal cage or caging system. The provider provides the pre-packaged and uncontaminated fluid (e.g., water, or fluid with nutrients etc., as needed by an animal) for use preferably by delivering sanitized, fluid-filled, bags to a site designated by a user. Alternatively, the provider may locate a sealing apparatus, material for making the fluid bags and fluid supply at a location designated by the user. Thereafter, the provider will assemble, fill and seal the appropriate number of fluid bags for a user at the designated location. In a second method the provider provides a sealing apparatus and the material for making the fluid bags to a user. In this second method the provider may also supply any appropriate fluid to the user at a location designated by the user. The user thereafter assembles, fills and seals the fluid bags for use in the fluid delivery system of the invention as appropriate. A fluid bag (or pouch) filling and sealing method and system 300, in accordance with an embodiment of the invention, is illustrated in FIG. 26. Bag material (or film) 310, which may be formed of any suitable material as described above, is stored in bulk form, such as, for example, in roll form. As the process continues, bag material 310 is moved over bag forming portion 330 such that the generally flat shape of bag material 310 is formed into a tube. As the process continues, a vertical seal device 340 forms a vertical seal in bag material 310, thus completing the formation of a tube. Contents supply portion 320 serves to add ingredients, via, for example, gravity feed, into the tube of bag material 310. Contents supply portion 320 may include liquid and powder storage containers, and various pumps and other supply means, such that, for example, fluid (or water) 70, either with or without any additives as discussed above, may be added and metered out in appropriate quantities as is known in the art. Additionally, contents supply portion 320 may include heating and/or sterilizing equipment such that the contents supplied from contents supply portion 320 are in a generally sterilized condition. Next, horizontal seal device 350 forms a horizontal seal, either thermally, by adhesives, or by some other art recognized method as would be known to one skilled in the art. The horizontal seal serves to isolate the contents of the tube into separate portions. Next, the bag cutting device cuts the bag material at the horizontal seal to form individual fluid bags 60 containing fluid 70. Of course, in accordance with the spirit of the invention, the exact steps taken to form the fluid bags 60 may be varied as a matter of application specific design choice. In some embodiments of the invention steps may be added, left out, or performed in a different order. Additionally, the contents and bag material 310 of fluid bags 60 may be sterilized either before or after the completed bags are formed, or not at all. In an embodiment of the invention, and with reference to FIGS. 27-29, the fluid 70 is heated to approximately 180° F., and the fluid bags are stacked in storage containers 370 with the result that the fluid 70, fluid bags 60 and storage containers all become sterilized to a satisfactory degree. In an embodiment of the invention, a cage body 98 may be used as such a storage container. Additional parts of this process may also be automated, as is shown by the use of robotic arm 380 in stacking containers. Storage containers (or totes) 370 (or cage bodies 98) may also be supplied with fluid bags 60 at a workstation 382, before placement in a isolation and caging rack system 600. Additionally, storage containers 370 (or cage bodies 98) may be passed through various other sterilizing devices. As described above, the provider may provide a bag filling and sealing apparatus and the material for making the fluid bags to a user. The user thereafter assembles, fills and seals the fluid bags for use in the fluid delivery system in accordance with certain embodiments. In such instances, the filling and sealing apparatus can be installed on site at, for example, research laboratories, pharmaceutical companies, government agencies, universities, contract research companies, breeders and chemical companies, among others. Typically, these types of facilities are frequently Association for Assessment and Accreditation of Laboratory Animal Care International (AALAC) inspected and require approval with respect to Good Laboratory Practice (GLP) U.S. Department of Health and Human Services Food and Drug administration (FDA) requirements to run such a facility. To meet these strict certification requirements, these facilities generally have a central wash room complex where equipment such as cages and racks and other accessories are routinely sent to be cleaned washed and sanitized using washing machines, detergents, and the like. Typically, these areas are organized and fed from building flow patterns referred to as the dirty side of the wash area and clean side of the wash area. This is done to prevent the transfer of dirty particles into clean corridors wherein the animal rooms are re-supplied with clean equipment and animals. In accordance with these flow patterns, people at the facilities also follow the flow patterns, and may also be required to wear protective clothing such as gowning and disposable shoe covers. The flow patterns also pertain to the movement of equipment. Equipment being brought to the laboratory rooms must get there by way of the clean side of the rack washer in the wash room. The dirty side of the wash room typically contains rack washers, cage tunnel washers, autoclaves, disposal cans for dirty bedding and the like. These machines are typically set in concrete pits and are plumbed and wired as permanent installations in the facility building. Most of the equipment is accessed through doors that allow loading of racks, cages and equipment that are placed into these washing machines. These machines are typically positioned flush with a washroom divider wall. Equipment is placed in the washing machine at the dirty side, passes through an opening in the wall, and exits on the clean side of the washroom. After the equipment is loaded, it is typically washed with hot water and detergents for approximately fifteen to twenty minutes. On the clean side, after the wash cycle is complete, staff will then open the doors and remove the washed equipment into the clean staging area. The floors in these clean areas are typically formed of tile, epoxy, and/or epoxy stone mix, to create a waterproof area, with floor drains. Racks (like cars in a car wash) come out dripping wet, and the drains facilitate drainage of dripping water. Other activities typically performed on the clean side of the wash room include the filling of bottles with water and the charging of cage racks with water (i.e., purging the rack automatic watering system). Accordingly, because the charging of racks is typically performed on the clean side of the wash room, the clean side typically contains access to the main house feed of water, as well as a water treatment and/or filtration system. Such a system may consist of systems for the chlorination, acid treatment, and/or micron filtration of the water. Also typically included in such a system is a pressure reduction station to allow connection of the treated water to racks configured for automatic watering, to fill them and purge the racks from old water latent in the systems. As stated above, the bag filling and forming apparatus can be advantageously located at the clean side of the wash room. In certain embodiments, the bag filling and forming apparatus requires about sixteen square feet of floor space, although alternatively, the apparatus may be configured to require more or less floor space. In certain embodiments, the bag filling and forming apparatus can include industrial grade casters and can be rolled into place. The bag filling and forming apparatus can comprise built-in floor jacks that allow leveling and semi-permanent location, once placed. In certain embodiments, the bag forming and filling apparatus is pre-wired and fitted to accept a 110/220 VAC, 20 amp, 50/60 Hz supply dedicated power line near the machine. Of course, other power supplies could be used as is known to those skilled in the art, as instructed by this disclosure. With reference to FIG. 30, in certain embodiments, a 1½ inch cold water line 420 downstream of the existing in-house treatment system is used to supply water to the bag filling and forming apparatus 450. Of course, other water line sizes could be used as is known to those skilled in the art, as instructed by this disclosure. As described above, in certain embodiments, the bag (or pouch) material is provided in rolls 410. In such embodiments, a mobile roll lifting device 430 may be provided to the clean side of the wash room so that rolls of bag material 410 may be easily maneuvered from, for example, a pallet, to the bag filling and forming apparatus 450. In certain embodiments of the system, an indexing or other type motor driven conveyor 460 can also be located on the clean side of the wash room to facilitate transport of the filled water bags 440 away from the filling and forming apparatus. Box-shaped totes 470, preferably formed of translucent plastic, can also be provided at the clean side of the wash room. In certain embodiments, the totes 470 can be rigid such that they may be stacked when full, and nested when empty for easy storage. In certain embodiments, a mobile tote conveyor platform 465 can be used to position an open tote 470 at the end of motorized conveyor 460 until the tote 470 is filled with full water bags 440. The mobile tote conveyor platform 465 can then be moved to a tote cart 480. Tote cart 480 can be provided to facilitate the transport of the totes 470 filled with water bags 440 to a laboratory or other area. Generally, in certain embodiments, the water bags 440 are filled and formed in the clean side of the washroom, and then the totes 470 are filled and stored with the full water bags 440. The totes 470 can then be transported on the tote cart 480 to rooms and/or hallways where animal cages need service and a re-supply of water. Disposable valves (e.g., valves formed with plastic components) can then be removed from sanitized packaging, and inserted into apertures in diet delivery systems or wire bar lid inserts, and then, in turn, the water bags (or pouches), can be positioned such that the valves pierce the water bags and water may flow from the bags, through the valves, and be accessed by animals in cages. In alternate embodiments, the valves used need not be disposable or plastic, but could be formed of stainless steel or other suitable materials as is known to those skilled in the art. The used (near empty) pouches are removed from the cages, are placed in containers, such as, for example, empty totes, and transported to the dirty side of the washroom area. In certain embodiments, a compactor/bagging machine 490 can be supplied to the dirty side of the washroom. The compactor can be used to compress used pouches and valves into a compact bundle, or disposable bag, for easy disposal. With reference to FIG. 31, there is shown a schematic of a typical flow path at a laboratory facility 500. Laboratory research rooms 510 are located between dirty corridor 520 and clean corridor 530. Laboratory exits 512 connect the laboratory research rooms 510 with the dirty corridor 520, while laboratory entrances 514 connect the laboratory research rooms 510 to the clean corridor 530. The central washroom 540 is also positioned between the dirty corridor 520 and the clean corridor 530. Washroom entrance 542 leads from dirty corridor 520 to the dirty side 546 of the washroom 540. As described above, a compactor/bagging machine 490 to facilitate disposal of water bags 440 and valves can be placed at the dirty side 546 of washroom 540. The clean side 548 of the washroom 440 is connected to clean corridor 530 via washroom exit 544. As described above, in certain embodiments, bag filling and forming apparatus 450 is located at the clean side 548 of washroom 540. As described above, in a typical flow path, water bags are produced by the water bag filling and forming apparatus 450 at the clean side 548 of washroom 540. The water bags are transported out exit 544 into clean corridor 530, and then through one of the laboratory entrances 514 into one of the laboratory research rooms 541 where the water bags are placed into cage level barrier-type cages. The used water bags are removed from the cages, placed into empty totes, and transported out one of the laboratory exits 512 into dirty corridor 520, and then through washroom entrance 542 into the dirty side 546 of washroom 540, where, in certain embodiments, the used water bags and valves are compacted in a compactor/gagging apparatus 490 for easy removal. In certain embodiments, the compacted water bags and valves can be washed prior to removal. With reference to FIG. 32, there is shown a schematic of another typical flow path at a laboratory facility 700. Laboratory research rooms 710 are located next to corridor 725. Laboratory combined entrance/exits 713 connect the laboratory research rooms 710 with the one way corridor 725. Washroom entrance 742 leads from corridor 725 to the dirty side 746 of the washroom 740. The clean side 748 of the washroom 740 is connected to corridor 725 via washroom exit 744. As described above, in certain embodiments, bag filling and forming apparatus 450 is located at the clean side 748 of washroom 740. As also described above, in a typical flow path, water bags are produced by the water bag filling and forming apparatus 450 at the clean side 748 of washroom 740. The water bags are transported out exit 744 into one way corridor 725, and then through one of the laboratory entrance/exits 713 into one of the laboratory research rooms 741 where the water bags are placed into cage level barrier-type cages. The used water bags are removed from the cages, placed into empty totes, and transported out one of the laboratory entrance/exits 713 into corridor 725, and then through washroom entrance 742 into the dirty side 746 of washroom 740, where, in certain embodiments, the used water bags are compacted for easy removal. With reference to FIG. 33, there is illustrated an exemplary method 800 of providing water bags in accordance with certain embodiments. In this method, a rack and cage system having a plurality of cage level barrier-type cages is provided at a laboratory research room for performing an animal study. Step 810. Next, bag material (or film), for the water bags (or pouches) is provided to the laboratory facility site. Step 820. Next, a water bag filling and forming apparatus is provided to the clean side of the washroom at the laboratory facility. Step 830. Next, disposable valves are provided for use with the water bags. Step 840. In this embodiment, for sake of clarity, the steps are depicted being performed one at a time, in a specific order. The steps need not be performed in the depicted order shown, however, and the various steps may be performed in other orders, and/or one or more of the steps may be performed simultaneously. In addition, in certain embodiments, one or more of the steps may be omitted, and/or one or more of the steps may be performed more than once, and/or additional steps may also be performed. Another method 900 of providing sealed water bags for use in cage level barrier-type cages for animal studies is depicted in FIG. 34. In certain embodiments, a rack and cage system is provided for placement in a laboratory research room. Step 910. Bag material (film) is provided. Step 920. Next, in certain embodiments, a roll lift device is provided so that rolls of bag material may be easily maneuvered from pallets to the bag filling and forming apparatus. Step 930. Next, a water bag filling and forming apparatus is provided at the clean side of the washroom. Step 940. Next, a conveyor system is provided for the handling of the water bags after they are produced by the water bag filling and forming apparatus. Step 950. Next, totes for storing and transporting the filled water bags can be provided. Step 960. A tote cart for transporting several totes can then be provided. Step 970. Next, disposable fluid delivery valves can be supplied for insertion into the diet delivery system or module. Each of the filled water bags is then positioned in a diet delivery module such that a valve pierces the bag and water may flow out of the bag, through the valve, and be accessed by animals. Step 980. Used water bags and valves are transported from the clean side of the facility to the dirty side of the facility. Next, a compactor/bagging apparatus (disposal device) is provided for compacting the used water bags and valves after use. Step 990. In this embodiment, for sake of clarity, the steps are depicted being performed one at a time, in a specific order. The steps need not be performed in the depicted order shown, however, and the various steps may be performed in other orders, and/or one or more of the steps may be performed simultaneously. In addition, in certain embodiments, one or more of the steps may be omitted, and/or one or more of the steps may be performed more than once, and/or additional steps may also be performed. Accordingly, by way of providing a bag forming apparatus at a clean side of a laboratory washroom at the laboratory facility site, wherein the bag forming apparatus is capable of providing sealed bags of water for use in the cage level barrier-type cages, users at a laboratory facility are freed from the significant investment in time and expense necessitated by the use of water bottles. In addition, the laboratory facility is also freed from the expense and dangers related to the use of automatic watering systems. Because the bag forming apparatus is provided at the clean side of the laboratory washroom, the laboratory facility may take advantage of the features of the washroom, such as the presence of a main water feed, and dedicated power circuits. In addition, by providing water bags at the clean side of the laboratory facility washroom, personnel at the laboratory facility may make use of their pre-existing clean and dirty flow paths, thus allowing for harmonious integration of the water bag and fluid delivery valve system into the existing laboratory facility environment. Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to exemplary embodiments thereof, it would be understood that various omissions and substitutions and changes in the form and details of the disclosed invention may be made by those skilled in the art without departing from the spirit of the invention. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention that, as a matter of language, might be said to fall there between. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates generally to fluid delivery systems and in particular to a fluid delivery system and method for caging or storage systems for animals. 2. Description of Related Art A large number of laboratory animals are used every year in experimental research. These animals range in size from mice to non-human primates. To conduct valid and reliable experiments, researchers must be assured that their animals are protected from pathogens and microbial contaminants that will affect test results and conclusions. Proper housing and management of animal facilities are essential to animal well-being, to the quality of research data and teaching or testing programs in which animals are used, and to the health and safety of personnel. Ordinarily, animals should have access to potable, uncontaminated drinking water or other needed nutrient containing fluids according to their particular requirements. Water quality and the definition of potable water can vary with locality. Periodic monitoring for pH, hardness, and microbial or chemical contamination might be necessary to ensure that water quality is acceptable, particularly for use in studies in which normal components of water in a given locality can influence the results obtained. Water can be treated or purified to minimize or eliminate contamination when protocols require highly purified water. The selection of water treatments should be carefully considered because many forms of water treatment have the potential to cause physiologic alterations, changes in microflora, or effects on experimental results. For example, chlorination of the water supply can be useful for some species but toxic to others. Because the conditions of housing and husbandry affect animal and occupational health and safety as well as data variability, and effect an animal's well-being, the present invention relates to providing a non-contaminated, replaceable, disposable source of fluid for laboratory animals in a cage level barrier-type cage or integrated cage and rack system to permit optimum environmental conditions and animal comfort. Animal suppliers around the world have experienced an unprecedented demand for defined pathogen-free animals, and are now committed to the production and accessibility of such animals to researchers. Likewise, laboratory animal cage manufacturers have developed many caging systems that provide techniques and equipment to insure a pathogen free environment. For example, ventilated cage and rack systems are well known in the art. One such ventilated cage and rack system is disclosed in U.S. Pat. No. 4,989,545, the contents of which are incorporated herein by reference, assigned to Lab Products, Inc., in which an open rack system including a plurality of shelves, each formed as an air plenum, is provided. A ventilation system is connected to the rack system for ventilating each cage in the rack, and the animals therein, thereby eliminating the need for a cage that may be easily contaminated with pathogens, allergens, unwanted pheromones, or other hazardous fumes. It is known to house rats, for example, for study in such a ventilated cage and rack system. The increasing need for improvement and technological advancement for efficiently, safely housing and maintaining laboratory animals arises mainly from contemporary interests in creating a pathogen-free laboratory animal environment and through the use of immuno-compromised, immuno-deficient, transgenic and induced mutant (“knockout”) animals. Transgenic technologies, which are rapidly expanding, provide most of the animal populations for modeling molecular biology applications. Transgenic animals account for the continuous success of modeling mice and rats for human diseases, models of disease treatment and prevention and by advances in knowledge concerning developmental genetics. Also, the development of new immuno-deficient models has seen tremendous advances in recent years due to the creation of gene-targeted models using knockout technology. Thus, the desire for an uncontaminated cage environment and the increasing use of immuno-compromised animals (i.e., SCID mice) has greatly increased the need for pathogen free sources of food and water. One of the chief means through which pathogens can be introduced into an otherwise isolated animal caging environment is through the contaminated food or water sources provided to the animal(s). Accordingly, the need exists to improve and better maintain the health of research animals through improving both specialized caging equipment and the water delivery apparatus for a given cage. Related caging system technologies for water or fluid delivery have certain deficiencies such as risks of contamination, bio-containment requirements, DNA hazardous issues, gene transfer technologies disease induction, allergen exposure in the workplace and animal welfare issues. Presently, laboratories or other facilities provide fluid to their animals in bottles or other containers that must be removed from the cage, disassembled, cleaned, sterilized, reassembled, and placed back in the cage. Additionally, a large quantity of fluid bottles or containers must be stored by the labs based on the possible future needs of the lab, and/or differing requirements based on the types of animals studied. This massive storage, cleaning and sterilization effort, typically performed on a weekly basis, requires large amounts of time, space and human resources to perform these repetitive, and often tedious tasks. Further, glass bottles (and the handling thereof) can be dangerous and also relatively costly. Bottle washing machines, bottle fillers, wasted water, hot water, wire baskets to hold bottles, sipper tubes, rubber stoppers, the ergonomic concerns of removing stoppers, screw caps insertion of sipper tubes are all problems inherent to the use of water bottles to provide water to animals. Although automatic watering systems are available the cost per cage is too costly for many institutions. Stainless steel valves and manifolds need constant purging of slime and buildup of mineral deposits. The human factors of handling wire baskets while loading and unloading bottles has led to industry wide back injuries, carpel wrist injury, and eye injury from broken glass and other human factor ergonomic risks. By some estimates, the cost of injury related costs to industry and the lost productivity in the workplace amount to millions of dollars annually. In addition, the use of water bottles typically leads to large energy costs because the cleaning of the water bottles typically requires hot water heated to approximately 180 degrees F. and the washing of all of the components of the water bottles and caps with dangerous chemicals. As such, a need exists for an improved system for delivering fluid to laboratory animals living in cage level barrier-type rack and cage systems. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention satisfies this and other needs. Briefly stated, in accordance with an embodiment of the invention, a fluid delivery system for delivering a fluid to an animal caging system for housing an animal is described. The fluid delivery system may comprise a fluid delivery valve assembly adapted to be coupled to a fluid bag holding a fluid. By advantageously using sanitized fluid bags, that may be disposable, the invention may minimize the need for the use of fluid bottles that typically must be removed from cages, cleaned, and sanitized on a frequent basis. The delivery system may be utilized in a single cage or in multiples cages integrated into ventilated cage and rack systems known in the art. An embodiment of the invention described herein provides for a fluid delivery system for delivering a fluid from a fluid bag to an animal caging system for housing an animal and may comprise a fluid delivery valve assembly, wherein the fluid delivery valve assembly is adapted to be coupled to the fluid bag to facilitate the providing of the fluid to an animal in the caging system. The fluid delivery valve assembly may further comprise an upper member having a piercing member and a connecting member, the upper member having a fluid channel defined therethrough, a base having a flange member and a base fluid channel defined therethrough, wherein the base is designed to be matingly coupled to the upper member. The fluid delivery valve assembly may further comprise a spring element disposed within the base fluid channel and a stem member disposed in part within the base fluid channel, wherein a portion of the spring element abuts the stem member to apply a biasing force. Another embodiment of the invention may provide for a method for delivering fluid to one or more animal cages comprising providing sealed sanitized bags of fluid for use in an animal cage or caging system. The method may further comprise providing bag material to be used in the formation of fluid bags. Another embodiment is directed to a method for facilitating the delivery of water to a plurality of cage level barrier-type cages, for housing animals for an animal study. The method comprises providing a plurality of cage level barrier-type cages for an animal study at a laboratory facility site, and disposing a bag forming apparatus at a clean side of a laboratory washroom at the laboratory facility site. The bag forming apparatus is capable of providing sealed bags of water for use in the cage level barrier-type cages. In addition, the method can further comprise providing bag material to the laboratory facility site. Another embodiment of the invention involves a method for facilitating the delivery of water to a plurality of cage level barrier-type cages disposed at a laboratory facility site, for housing animals for an animal study. The method comprises disposing a bag forming apparatus at a clean side of a laboratory washroom at the laboratory facility site; wherein the bag forming apparatus is capable of providing sealed bags of water for use in the cage level barrier-type cages. Another embodiment of the invention is directed to a system for facilitating the delivery of water to a plurality of cage level barrier-type cages disposed at a laboratory facility site, for housing animals for an animal study. The system comprises a bag forming apparatus designed and configured for placement at a clean side of a laboratory washroom at the laboratory facility site, wherein the bag forming apparatus is capable of providing sealed bags of water for use in the cage level barrier-type cages. Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification. Other features and advantages of this invention will become apparent in the following detailed description of exemplary embodiments of this invention with reference to the accompanying drawings. | 20040413 | 20060110 | 20050203 | 92927.0 | 3 | MICHENER, JOSHUA J | METHOD AND SYSTEM OF PROVIDING SEALED BAGS OF FLUID AT THE CLEAN SIDE OF A LABORATORY FACILITY | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,823,920 | ACCEPTED | Materials treatable by particle beam processing apparatus | The present invention is directed to materials treatable by electron beam (EB) processing, such as materials for flexible packaging. The material comprises a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols. The processing apparatus for EB treating the material operates at a low voltage, such as 125 kVolts or less. | 1. A layered material, comprising: a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols. 2. The layered material according to claim 1, wherein the acrylate ester in the ink formulation and/or lacquer is a multifunctional acrylate ester selected from acrylated polyols having a molecular weight ranging from 150 to 600; polyester acrylates having a molecular weight ranging from 1000 to 2000; polyether acrylates having a molecular weight ranging from 200 to 1500; polyester urethane acrylates having a molecular weight ranging from 400 to 2000; polyurea acrylates having a molecular weight ranging from 400 to 2000; and epoxy acrylates having a molecular weight ranging from 300 to 1000. 3. The layered material according to claim 1, wherein the acrylate ester in the ink formulation and/or lacquer is a multifunctional acrylate ester selected from pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, trimethylolpropane triacrylate, glycerol triacrylate, triacrylate ester of tris(2-hydroxy-ethyl)isocyanurate, hexanediol diacrylate, dipentaerythritol hexacrylate, and ethoxylated and propoxylated derivatives thereof. 4. The layered material according to claim 1, wherein the substrate comprises at least one polymer selected from polyolefins, polyolefin copolymers, polystyrene, polyesters, polyamides, polyimides, polyacrylonitrile, polyvinylchloride, polyvinyl dichloride, polyvinylidene chloride, polyacrylates, ionomers, polysaccharides, silicones, natural rubbers, and synthetic rubbers. 5. The layered material according to claim 1, wherein the lacquer has a normalized thickness ranging from 0.5 g/m2to 20 g/m2. 6. The layered material according to claim 1, wherein the lacquer coats a portion of the ink formulation. 7. The layered material according to claim 1, wherein the lacquer coats the ink formulation. 8. The layered material according to claim 1, wherein the lacquer coats the ink formulation and the substrate surface. 9. The layered material according to claim 8, further comprising a second substrate positioned on the lacquer. 10. The layered material according to claim 1, wherein the ink formulation and lacquer are curable by exposure to highly accelerated particles generated by a particle beam processing device operating at a voltage in a range of 125 kVolts or less. 11. The layered material according to claim 10, wherein the ink formulation and lacquer is curable by exposure to highly accelerated particles generated by a particle beam processing device operating at a voltage in a range of 110 kVolts or less. 12. The layered material according to claim 11, wherein the highly accelerated particles emit energy ranging from 0.5 Mrads to 10 Mrads. 13. A layered material, comprising: a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one polymer derived from at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one polymer derived from at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols. 14. The layered material according to claim 13, wherein at least a portion of the ink formulation is bonded to at least a portion of the lacquer. 15. The layered material according to claim 14, wherein at least a portion of the ink formulation is chemically bonded to at least a portion of the lacquer. 16. The layered material according to claim 13, wherein the lacquer coats a portion of the ink formulation. 17. The layered material according to claim 13, wherein the lacquer coats the ink formulation. 18. The layered material according to claim 13, wherein the lacquer coats the ink formulation and the substrate surface. 19. A package comprising the material according to claim 13. 20. A layered material, comprising: a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one first polymer; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one second polymer, wherein the at least one first polymer is bonded to the at least one second polymer. 21. The layered material according to claim 20, wherein the at least one first polymer is chemically bonded to the at least one second polymer. 22. The layered material according to claim 21, wherein the at least one first polymer is covalently bonded to at least a portion of the at least one second polymer. 23. The layered material according to claim 20, wherein the at least one first polymer is crosslinked to at least a portion of the at least one second polymer. 24. The layered material according to claim 20, wherein the at least one first polymer and the at least one second polymer comprise an interpenetrating network. 25. The layered material according to claim 20, wherein the at least one first and second polymers are independently derived from at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides. 26. A package comprising the layered material according to claim 20. 27. A method for making a layered material, comprising: providing a substrate; applying an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols; and applying at least a portion of the ink formulation with a lacquer, the lacquer comprising at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols. 28. The method according to claim 27, further comprising exposing the ink formulation and lacquer to highly accelerated particles generated by a particle beam processing device operating at a voltage of 125 kVolts or less. 29. The method according to claim 28, further comprising exposing the ink formulation and lacquer to highly accelerated particles generated by a particle beam processing device operating at a voltage of 110 kVolts or less. 30. The method according to claim 27, wherein the highly accelerated particles emit energy ranging from 0.5 Mrads to 10 Mrads. 31. The method according to claim 27, wherein the highly accelerated particles cause polymerization of the monomers in the ink formulation and the lacquer. 32. The method according to claim 31, wherein the polymerization is a free radical polymerization. 33. The method according to claim 32, wherein the lacquer and ink formulation comprise monomers selected from acrylate esters. 34. The method according to claim 31, wherein polymerization is a cationic polymerization. 35. The method according to claim 34, wherein the lacquer and ink formulation comprise monomers selected from cycloaliphatic diepoxide and polyols. 36. The method according to claim 27, the ink formulation is applied by at least on method selected from flexography printing, rotor-gravure printing, offset lithography printing, and spray printing. 37. The method according to claim 27, wherein the lacquer is applied by at least one method selected from a roll coating application, an offset gravure application, and a direct gravure application. 38. A layered material, comprising: a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one monomer curable by free radical and/or cationic polymerization; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one monomer curable by free radical and/or cationic polymerization. | FIELD OF THE INVENTION This invention relates to layered materials treatable with a particle beam processing apparatus. The layered materials can be useful for flexible packaging applications. BACKGROUND OF THE INVENTION A particle beam processing device is commonly used to expose a substrate or coating to highly accelerated particle beams, such as an electron beam (EB), to cause a chemical reaction, such as a polymerization, on the substrate or coating. In EB processing, energetic electrons can be used to modify the molecular structure of a wide variety of products and materials. Electrons can be used, for example, to alter specially designed liquid coatings, inks and adhesives. For example, during EB processing, electrons break bonds and form charged particles and free radicals, which can cause polymerization to occur. Liquid coatings treated with EB processing may include printing inks, varnishes, silicone release coatings, primer coatings, pressure sensitive adhesives, barrier coatings and laminating adhesives. EB processing may also be used to alter and/or enhance the physical characteristics of solid materials such as paper, substrates and non-woven textile substrates, all specially designed to react to EB treatment. A particle beam processing device generally includes three zones, i.e., a vacuum chamber zone where a particle beam is generated, a particle accelerator zone, and a processing zone. In the vacuum chamber, a tungsten filament(s) is heated to, for example, about 2400K, which is the thermionic emission temperature of tungsten, to create a cloud of electrons. A positive voltage differential is then applied to the vacuum chamber to extract and simultaneously accelerate these electrons. Thereafter, the electrons pass through a thin foil and enter the processing zone. The thin foil functions as a barrier between the vacuum chamber and the processing zone. Accelerated electrons exit the vacuum chamber through the thin foil and enter the processing zone, which is usually at atmospheric conditions. Electron beam processing devices that are commercially available at the present time generally operate at a minimum voltage of approximately 125 kVolts. Additionally, U.S. patent Publication No. 2003/0001108, the disclosure of which is incorporated by reference herein, describes an EB unit that operates at lower voltages, such as 110 kV or lower. Materials that can be treated with this lower voltage electron beam equipment (110 kV or lower) include coatings, inks, and laminating adhesives for flexible food packaging. One challenge facing those using electron beam processing for curing either overprint varnishes or laminating adhesives on conventional solvent or water-based inks is ink adhesion. Either the overprint varnish or the adhesive has little or no wettability or adhesion to the ink, or the ink itself lacks cohesiveness and can split or delaminate from the base film upon applying any force such as experienced during a standard T-peel test or tape adhesion test. Accordingly, there exists a need to continue developing materials that can be treated with EB processing. SUMMARY OF THE INVENTION One embodiment of the present invention provides a layered material, e.g., a material having two or more layers. The material can be curable by exposure to highly accelerated particles, such as an electron beam. Further, the layered material can comprise: a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one monomer curable by free radical and/or cationic polymerization; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one monomer curable by free radical and/or cationic polymerization. Another embodiment of the present invention provides a layered material, comprising: a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols. Another embodiment of the present invention provides a layered material, comprising: a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one polymer derived from at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one polymer derived from at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols. Another embodiment of the present invention provides a layered material, comprising: a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one first polymer; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one second polymer, wherein at least a portion of the at least one first polymer is bonded to at least a portion of the at least one second polymer. Another embodiment of the present invention provides a method for making a layered material, comprising: providing a substrate; applying an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols; and applying a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols. Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of the particle beam processing device according to one embodiment of the present invention; and FIG. 2 is a schematic view of a voltage profile of an electron beam. DESCRIPTION OF THE EMBODIMENTS One embodiment of the present invention provides a layered material, e.g., a material having two or more layers. The material can be curable by exposure to highly accelerated particles, such as an electron beam. Further, the layered material can comprise: a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one monomer curable by free radical and/or cationic polymerization; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one monomer curable by free radical and/or cationic polymerization. In one embodiment, any type of monomer curable by free radical and/or cationic type polymerization mechanisms can be useful in the invention provided that the ink physical properties like viscosity, appearance etc. do not render it unusable by the conventional application methods. In one embodiment, the ink formulation and lacquer comprise at least one monomer independently selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols. In one embodiment, the ink formulation and lacquer comprise monomers that can be cured, e.g., polymerized, upon exposure to highly accelerated particles, such as electrons generated by a particle beam. The polymerization can occur within the individual layers, e.g., ink formulation and lacquer, such that the polymers formed can cause the layers to be bonded to each other. In one embodiment, polymerization occurs between the layers forming, for example, an interpenetrating network. Alternatively, crosslinks can be formed between the ink formulation and the lacquer. “At least one monomer,” as used herein, refers to one or a combination of two or more monomers. In one embodiment, the lacquer coats a portion of the ink formulation. In another embodiment, the lacquer coats the entire ink formulation printed on the substrate. In yet another embodiment, the lacquer coats the ink formulation and substrate surface, such as the entire ink formulation and the portion of the substrate surface that is not printed with the ink formulation. Because both the ink formulation and the lacquer comprise monomer components that can be cured, such as by an EB process, the resulting cured product can result in the ink being cohesive and/or integrated with the lacquer. Accordingly, in the cured product, the ink can have good adhesion to the lacquer. In one embodiment, good adhesion can be determined by exposing the cured, printed material to a standard T-peel test or tape adhesion test. For example, where the lacquer coats a portion of the printed ink formulation/substrate surface, the adhesion is tested with a tape adhesion test. In another example, where the lacquer coats the entire surface of the printed ink formulation/substrate surface, e.g., as in a laminating adhesive, the adhesion is tested with a T-peel test. Another embodiment of the present invention provides the cured product, e.g., a layered material, comprising: a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one first polymer; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one second polymer, wherein the at least one first polymer is bonded to the at least one second polymer. In one embodiment, at least a portion of the at least one first polymer is bonded to at least a portion of the at least one second polymer. For example, the polymers can be surface-bonded to each other. Alternatively, at least portion of the first polymer, i.e., in the ink formulation, can penetrate into the second polymer. In one embodiment, the at least one first polymer is adhered, for example, like an adhesive, to the at least one second polymer. In one embodiment, the at least one first polymer is chemically bonded to the at least one first polymer. In one embodiment, “chemically bonded” refers to covalent bonds formed between at least a portion of each of the polymers. In one embodiment, an interpenetrating network of chemical bonds exist throughout the ink formulation/lacquer structure. In another embodiment, crosslinks may form between the first polymer in the ink formulation, and the second polymer in the lacquer. In one embodiment, the ink formulation and lacquer may comprise polymers derived from at least one monomer selected from acrylate esters including multifunctional acrylates for free radical polymerization, and vinyl ethers, cycloaliphatic diepoxides, and polyol for cationic polymerization. The phrase “polymers derived from at least one monomer selected from,” as used herein, means polymers derived from one or more monomers to form homopolymers or copolymers. In one embodiment, the lacquer and ink formulation comprise monomers selected from acrylate esters, and the polymerization is a free radical polymerization. In another embodiment, the lacquer and ink formulation comprise monomers selected from cycloaliphatic diepoxide and polyol and the polymerization is a cationic polymerization. In one embodiment, the ink formulation or lacquer can comprise monomers such as a multifunctional acrylate ester. Exemplary multifunctional acrylate esters include: acrylated polyols having a molecular weight ranging from 150 to 600; polyester acrylates having a molecular weight ranging from 1000 to 2000; polyether acrylates having a molecular weight ranging from 200 to 1500; polyester urethane acrylates having a molecular weight ranging from 400 to 2000; polyurea acrylates having a molecular weight ranging from 400 to 2000; and epoxy acrylates having a molecular weight ranging from 300 to 1000. Specific examples of the multifunctional acrylate may include pentaerythritol tetraacrylate, ditrimethylol propane tetraacrylate, trimethylolpropane triacrylate, glycerol triacrylate, triacrylate ester of tris(2-hydroxyethyl)isocyanurate, hexanediol diacrylate, dipentaerythritol hexacrylate, and ethoxylated and propoxylated derivatives thereof. The lacquer can serve at least one of several purposes, including protecting the ink from smearing and scratching. The lacquer can also provide sufficient traction to enable the material to run through the EB machine. For aesthetic reasons, the lacquer can be used to create a high gloss finish for the packaged product. In one embodiment, the lacquer is an over-print varnish (OPV). The lacquer may also include wetting agents, defoamers, and other additives, such as waxes, to control the coefficient of friction (COF) and import desired functional properties, such as gas and aroma barrier properties. The lacquer may have a normalized thickness (expressed in terms of its mass density) ranging from 0.5 to 20 g/m2. In one embodiment, the lacquer has a thickness ranging from 1 to 10 g/m2, such as a thickness ranging from 2 to 5 g/m2. In one embodiment, the ink formulation comprises well known flexography inks, including solvent based, water based, and electron beam curable ink, such as Unicure™, available from Sun Chemicals Ink of Northlake, Ill. In one embodiment, rotogravure printing inks can be used. In one embodiment, the substrate comprises at least one polymer, such as thermoplastics. In another embodiment, the substrate comprises at least one polymer selected from: polyolefins, including oriented polypropylene (OPP), cast polypropylene, polyethylene and polyethylene copolymer; polyolefin copolymers, including ethylene vinyl acetate, ethylene acrylic acid and ethylene vinyl alcohol (EVOH), polyvinyl alcohol and copolymers thereof; polystyrene; polyesters, including polyethylene terephthalate (PET), or polyethylene naphthalate (PEN); polyamides, including nylon, and MXD6; polyimides; polyacrylonitrile; polyvinylchloride; polyvinyl dichloride; polyvinylidene chloride; polyacrylates; ionomers; polysaccharides, including regenerated cellulose; silicone, including rubbers or sealants; natural and synthetic rubbers. In one embodiment, the substrate comprises at least one material selected from: polysaccharides, including regenerated cellulose; glassine or clay coated paper; paper board, such as SBS polycoated paper; and Kraft paper. In one embodiment, the substrate comprises metallized films and vapor deposited metal oxide coated polymer films, including AlOx, SiOx, and TiOx, and OPP, PET, and PE ALOx coated films, SiOx coated OPP, and metallized PET films. For example, a metallization process can be a vacuum deposition process with an aluminum oxide. Here, the aluminum is heated to above melting temperature under a vacuum condition in a chamber. A continuous web is run through the vacuum chamber filled with molten aluminum via a series of rollers. Under a controlled condition, the molten aluminum is deposited on either one or both of its surfaces creating a precise thickness of aluminum metallization on the web. This metallization can be seen, for example, as the shiny silver-colored coating on the inner side of a bag of potato chips. In one embodiment, the substrate has a thickness sufficient to provide desired strength to the packaging and to maintain quality of the contents of a packaged product, such as a thickness ranging from 10 to 200 g/m2, or a thickness ranging from 30 to 90 g/m2, or ranging from 50 to 70 g/m2. In another embodiment, the substrate may have a thickness ranging from 100 to 1000 Angstroms. The source of the highly accelerated electrons can be a particle beam processing device. In one embodiment, the ink formulation and lacquer are curable by exposure to highly accelerated particles generated by a particle beam processing device operating at a voltage of 125 kVolts or less, such as a voltage of 1 10 kVolts or less. In another embodiment, the highly accelerated particles emit energy ranging from 0.5 Mrads to 10 Mrads. In one embodiment, the particles can be accelerated to an extent sufficient to cure the lacquer and ink formulation almost instantaneously or within approximately a few milliseconds. For the manufacturers of consumer food products, like chocolate bars, potato chips, candies, dried fruits, etc., where mass quantity production is desired, this can be a useful process since products can be quickly packaged and shipped to suppliers and consumers. Another embodiment of the present invention provides a method for making a layered material, comprising: providing a substrate; applying an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols; and applying a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols. In one embodiment, the ink formulation is applied by at least on method selected from flexography printing, rotor-gravure printing, offset lithography printing, and spray printing. In another embodiment, the ink formulation is applied as a label print. In one embodiment, the lacquer is applied by at least one method selected from a roll coating application, an offset gravure application, and a direct gravure application. In one embodiment, the method comprises exposing the ink formulation and lacquer to highly accelerated particles generated by a particle beam processing device operating at a voltage of 125 kVolts or less, such as a voltage of 110 kVolts or less. The particles can be accelerated to an extent sufficient to cause polymerization of the monomers in the ink formulation and the lacquer. In one embodiment, the highly accelerated particles emit electron doses energy ranging from 0.5 Mrads to 10 Mrads. In one embodiment, the lacquer is treated by using an EB machine having a power supply and operating at a voltage of 125 kVolts or less, such as a voltage of 110 kVolts or less. In one embodiment, the operating voltage of the EB machine may range from 60 to 110 kVolts, such as an operating voltage ranging from 70 to 110 kVolts, or from 90 to 110 kVolts. In one embodiment, the EB machine generates electrons emitting energy ranging from 0.5 to 10 Mrads to cure the lacquer and ink formulation. In one embodiment, the emitted electron energy ranges from 1 to 7 Mrads, such as energy ranging from 2 to 5 Mrads. In one embodiment, the lacquer is a laminating adhesive for laminating two substrates together where the lacquer covers the entire surface of the substrate and printed ink formulation—e.g. two plastic films, paper or paperboard laminated to plastic film. For example, the layered material can comprise a substrate, an ink formulation on the substrate and a lacquer on the entire ink/substrate surface. A second substrate, such as a thermoplastic film, can then be positioned on the lacquer, e.g., nipped with the first substrate. One example of a particle beam processing device for providing highly accelerated particles is described in U.S. patent Publication No. 2003/0001108. This device can be made relatively small in size and to operate at lower voltages and high efficiency. FIG. 1 schematically illustrates a particle beam processing device 100, including power supply 102, particle beam generating assembly 110, foil support assembly 140, and processing assembly 170. Power supply 102 can provide an operating voltage of 110 kVolts or less, such as a range of 90-100 kVolts, to the processing device 100. Power supply 102 may be of a commercially available type that includes multiple electrical transformers located in an electrically insulated steel chamber to provide high voltage to particle beam generating assembly 110. Particle beam generating assembly 110 can be kept in a vacuum environment of vessel or chamber 114. In an EB processing device, particle generating assembly 110 is commonly referred to as an electron gun assembly. Evacuated chamber 114 may be constructed of a tightly sealed vessel in which particles, such as electrons, are generated. Vacuum pump 212 can be provided to create a vacuum environment in the order of approximately 10−6 Torr, or other vacuum conditions as needed. Inside the vacuum environment of chamber 114, a cloud of electrons are generated around filament 112 when high-voltage power supply 102 sends electrical power to heat up filament 112. With sufficient heating, filament 112 glows white hot and generates a cloud of electrons. Electrons are then drawn from filament 112 to areas of higher voltage, because electrons are negatively charged particles and accelerated to extremely high speeds. Filament 112 may be constructed of one or more wires commonly made of tungsten, where two or more wires may be configured to be spaced evenly across the length of foil support 144 and emits electron beams across the width of a substrate 10. As shown in FIGS. 1 and 2, particle beam generating assembly 110 may include an extractor grid 116, a terminal grid 118, and a repeller plate 120. Repeller plate 120 repels electrons and sends the electrons toward extractor grid 116. Repeller plate 120 operates at a different voltage, such as a slightly lower voltage, than filament 112 to collect and redirect electrons escaping from filament 112 away from the electron beam direction as shown in FIG. 2. Extractor grid 116, operating at a slightly different voltage, such as a voltage higher than filament 112, attracts electrons away from filament 112 and guides them toward terminal grid 118. Extractor grid 116 controls the quantity of electrons being drawn from the cloud, which determines the intensity of the electron beam. Terminal grid 118, operating generally at the same voltage as extractor grid 116, acts as the final gateway for electrons before they accelerate to extremely high speeds for passage through foil support assembly 140. Filament 112 may operate at −110,000 Volts (i.e., 110 kV) and foil support assembly 140 may be grounded or set at 0 Volt. Repeller plate 120 may be selected to operate at −110,010 Volts to repel any electrons towards filament 112. Extractor grid 116 and terminal grid 118 may be selected to operate in a range of −110,000 Volts to −109,700 Volts. The electrons then exit vacuum chamber 114 and enter the foil support assembly 140 through a thin foil 142 to penetrate a coated material or substrate 10 to cause a chemical reaction, such as polymerization, crosslinking, or sterilization. The speed of the electrons may be as high as or above 100,000 miles per second. Foil support assembly 140 may be made up of a series of parallel copper ribs (not shown). Thin foil 142, as shown in FIG. 1, is securely clamped to the outside of foil support assembly 144 to ensure a leak-proof vacuum seal inside chamber 114. High speed electrons pass freely between the copper ribs, through thin foil 142 and into substrate 10 being treated. To prevent an undue energy loss, the foil can be made as thin as possible while at the same time providing sufficient mechanical strength to withstand the pressure differential between the vacuum state inside particle generating assembly 110 and processing assembly 170. The particle beam generating device can be made smaller in size and operate at a higher efficiency level when the thin foil of the foil support assembly is made of titanium or alloys thereof and has a thickness of 10 μm or less, such as a thickness ranging from 3-10 μm or ranging from 5-8 μm. Alternatively, thin foil 142 may also be constructed of aluminum or alloys thereof having a thickness of 20 μm or less, such as a thickness ranging from 6-20 μm, or ranging from 10-16 μm. Once the electrons exit the foil support assembly 140, they enter the processing assembly 170 where the electrons penetrate a coating, layer, web, or substrate 10 and cause a chemical reaction resulting in polymerization, crosslinking or sterilization. The product being EB treated can be transformed instantaneously, may need no drying or cooling, and may contain new and/or desirable physical properties. Products can be shipped immediately after processing. In operation, particle beam processing device 100 works as follows. A vacuum pump 212 evacuates air from chamber 114 to achieve a vacuum, such as a vacuum of approximately 10−6 Torr, at which point processing device 100 is fully operational. In particle generating assembly 110, particle gun assembly components, including repeller plate 120, extractor grid 116, and terminal grid 118, are set at three independently controlled voltages which initiate the emission of electrons and guide their passage through foil support 144. During the particle beam processing, a combination of electric fields inside evacuated chamber 114 create a “push/pull” effect that guides and accelerates the electrons toward thin foil 142 of foil support 144, which is typically at ground (0) potential. The quantity of electrons generated is directly related to the voltage of extractor grid 116. At slow production speeds, extractor grid 116 is set at a lower voltage than at high speeds, when greater voltage is applied. As the voltage of extractor grid 116 increases, so does the quantity of electrons being drawn from filament 112. The materials to be cured, for example, lacquer, ink formulations, and coatings, generally require a low oxygen environment to cause the chemical conversion from a liquid state into a solid state. The particle beam processing device according to this invention may include, as illustrated in FIG. 1, a plurality of nozzles 172, 174, 176, and 178 distributed in processing zone 170 to inject gas other than oxygen, such as an inert gas, to displace the oxygen therein. In one embodiment, nitrogen gas is selected to be pumped into processing zone 170 through nozzles 172, 174, 176, and 178 to displace the oxygen that would prevent complete curing. Process control system 200 may be set to provide a desired depth level of cure on a substrate or coating, which can allow particle beam processing device 100 to be calibrated to high precision specification. Process control system 200 can calculate the dose and the depth of electron penetration into the coating or substrate. The higher the voltage, the greater the electron speed and resultant penetration. Dose is the energy absorbed per unit mass and is measured in terms of megarads (Mrad), which is equivalent to 2.4 calories per gram. A higher number of electrons absorbed reflects a higher dose value. In application, dose is commonly determined by the material of the coating and the depth of substrate to be cured. For example, a dose of 5 Mrad may be required to cure a coating on a substrate that is made of rice paper and having a mass density of 20 gram/m2. Dose is directly proportional to the operating beam current which is the number of electrons extracted, and inversely proportional to the feed speed of the substrate, as expressed by the following formula: Dose=K·(I/S) wherein I is the current measured in mAmp, S is the feed speed of the substrate measured in feet/min, and K is a proportionality constant which represents a machine yield of the processing device, or the output efficiency of that particular processing device. Application of the particle beam processing device made according to this invention can be found in many industries including, for example, packaging, insulation films, reflective coatings and reflective materials, solar films, etc. Other fields, such as outer space suits and aircrafts, may also find this invention useful. For exemplary purposes only, an embodiment of the present invention is discussed with respect to an application of the particle beam processing device in the flexible food packaging field. EXAMPLE 1 This Example provides a comparison of adhesion of an ink formulation without monomers (Ink 1) versus ink formulations comprising monomers at various concentrations (Ink 2, 3, and 4). Ink 1 10 grams of ink (Aqua Sun Cyan R3271-48B), as received from Sun Chemicals, was placed in a 250 ml beaker. Ink 2 10 grams of ink (Aqua Sun Cyan R3271-48B), as received from Sun Chemicals, was placed in a 250 ml beaker. 0.25 grams of polyethylene glycol 200 diacrylate (PEG-200 SR-259, Sartomer) was added to the beaker with stirring at room temperature, for a monomer concentration of 2.5%. There were no signs of phase separation or incompatibility between the monomer and ink. Ink 3 10 grams of ink (Aqua Sun Cyan R3271-48B), as received from Sun Chemicals, was placed in a 250 ml beaker. 0.50 grams of polyethylene glycol 200 diacrylate (PEG-200 SR-259) was added to the beaker with stirring at room temperature, for a monomer concentration of 5%. There were no signs of phase separation or incompatibility. Ink 4 10 grams of ink (Aqua Sun Cyan R3271-48B), as received from Sun Chemicals was taken in a 250 ml beaker. 1.0 grams of polyethylene glycol 200 diacrylate (PEG-200 SR-259) was added to the beaker with stirring at room temperature, for a monomer concentration of 10%. There were no signs of phase separation or incompatibility. Film Preparation Eight 10″×100″ sheets of CEQW™ oriented polypropylene (OPP) film (Vifan Americas) having a thickness of 25 μm were provided. To the treated side of the OPP having a surface tension of 40 dynescm, Inks 1-4 from above were applied by a roll method. The coated films were dried in an oven at 110° C. until the inks were dry to touch. For Sample Nos. 1-4, the films were each coated with thermally dried Inks 1-4, followed by coating with an EB curable overprint varnish (EB1044-E, Sovereign Specialty Chemicals). The coating was applied with a Myer rod at a coat weight of about 5 g/m2. For Sample Nos. 4-8, the films were each coated with thermally dried Inks 1-4, followed by coating with an EB curable overprint varnish (EBLO10-2, Virkler chemicals). The coating was applied with a Myer rod at a coat weight of about 5 g/m2. Sample Nos. 1-8 were then cured with an ESI EB unit operating at 110 kV and 3 Mrads at a line speed of 10 m/min and at an oxygen concentration of <150 ppm. The overprint varnish for all the samples was cured upon EB irradiation. Adhesion of the overprint varnish was then tested by the above referenced scotch tape test. The results are shown in Table I, below: TABLE I Monomer EB OverPrint Sample No. Ink conc. in ink Varnish Adhesion 1 Ink #1 0% EB1044-E Slight ink removal 2 Ink #2 2.5% EB1044-E Excellent 3 Ink #3 5% EB1044-E Excellent 4 Ink #4 10% EB1044-E Excellent 5 Ink #1 0% EBLO 10-2 Spotty ink removal & ink split 6 Ink #2 2.5% EBLO 10-2 Excellent 7 Ink #3 5% EBLO 10-2 Excellent 8 Ink #4 10% EBLO 10-2 Excellent This Example demonstrates that the addition of an energy curable monomer like PEG-200 diacrylate in the ink improves ink cohesiveness and the adhesion to the overprint varnish. The addition of the monomer in amounts as little as 2.5% by weight of the as received ink is useful in improving ink adhesion and cohesiveness. EXAMPLE 2 This Example describes the preparation of a film with a solvent-based ink. 10 g of as received MOD Sealtech F-11 blue solvent based ink (Color Converting) was placed in a 250 mL beaker. To this ink, 0.5 g of 1,6-hexanedioldiacrylate (HDDA, Sartormer Chemicals) was added with stirring. The HDDA went into solution with no indication of phase separation. The beaker was covered with a layer of 1.0 mil aluminum foil and allowed to stand overnight at room temperature. No phase separation or increase in viscosity was observed for the ink+HDDA formulation. Sample 9 A 48 gauge acrylic coated PET film was coated with the ink+HDDA formulation by a hand roller method. The film was air-dried. An EB OPV (Sovereign Specialty Chemicals EB 1044-E) was coated on the dried ink. The OPV was EB treated at 110 kV and 3 Mrads under inert conditions. The coating cured well on the ink. It was then subjected to a Scotch tape and 3M 610 tape test. The ink and the coating adhered very well to the film substrate. EXAMPLE 3 This Example demonstrates the value of an electron beam curable monomer added to a conventional water based ink used for laminating adhesives. A typical laminate used in the flexible food packaging industry is of the type as shown in Table II, below. TABLE II TOP FILM 0.5 mil polyester (PET): 17.0 grams\m2 Ink (Solvent or water based): 3.0 grams\m2 EB curable laminating adhesive (lacquer): 3.0 grams\m2 Sealant of Polyethylene copolymer (PE): 40.0 grams\m2 Sample 10 Ink 1 from Example 1 was applied to a 48 gauge acrylic coated PET film by the roller method. The film was then air dried. An EB laminating adhesive (#76R, Liofol) was applied to the dry ink by a Myer rod at a coat weight of about 3.0 g/m2. The bottom film, comprising 175 gauge polyethylene (Pliant) was then laminated to it. The EB adhesive was cured using ESI EB unit operating at 110 kV and 3 Mrads of dose with the PET film exposed to the beam. Sample 11 Ink 3 from Example 1 was applied to a 48 gauge acrylic coated PET film by the roller method. The film was then air dried. An EB laminating adhesive (#76R, Liofol) was applied to the dry ink by a Myer rod at a coat weight of about 3.0 g/m2. The bottom film, comprising 175 gauge polyethylene (Pliant) was then laminated to it. The EB adhesive was cured using ESI EB unit operating at 110 kV and 3 Mrads of dose with the PET film exposed to the beam. The EB adhesive in either case cured very well. For both Samples 10 and 11, the adhesion of the PET to the PE for clear (non ink) areas was good. However, adhesion between the films in the ink areas was not as good for the laminate prepared by Sample 10 when compared to the laminate prepared in Sample 11. The laminate prepared from Sample 10 was ink split. The laminate prepared from Sample 11 presented more cohesiveness in the ink because of the addition of EB monomer (PEG-200 diacryate) added to the water-based ink. The electrons cured the adhesive as well as the ink in Sample 11 providing the ink the necessary cohesiveness obtained by cross-linking. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>A particle beam processing device is commonly used to expose a substrate or coating to highly accelerated particle beams, such as an electron beam (EB), to cause a chemical reaction, such as a polymerization, on the substrate or coating. In EB processing, energetic electrons can be used to modify the molecular structure of a wide variety of products and materials. Electrons can be used, for example, to alter specially designed liquid coatings, inks and adhesives. For example, during EB processing, electrons break bonds and form charged particles and free radicals, which can cause polymerization to occur. Liquid coatings treated with EB processing may include printing inks, varnishes, silicone release coatings, primer coatings, pressure sensitive adhesives, barrier coatings and laminating adhesives. EB processing may also be used to alter and/or enhance the physical characteristics of solid materials such as paper, substrates and non-woven textile substrates, all specially designed to react to EB treatment. A particle beam processing device generally includes three zones, i.e., a vacuum chamber zone where a particle beam is generated, a particle accelerator zone, and a processing zone. In the vacuum chamber, a tungsten filament(s) is heated to, for example, about 2400K, which is the thermionic emission temperature of tungsten, to create a cloud of electrons. A positive voltage differential is then applied to the vacuum chamber to extract and simultaneously accelerate these electrons. Thereafter, the electrons pass through a thin foil and enter the processing zone. The thin foil functions as a barrier between the vacuum chamber and the processing zone. Accelerated electrons exit the vacuum chamber through the thin foil and enter the processing zone, which is usually at atmospheric conditions. Electron beam processing devices that are commercially available at the present time generally operate at a minimum voltage of approximately 125 kVolts. Additionally, U.S. patent Publication No. 2003/0001108, the disclosure of which is incorporated by reference herein, describes an EB unit that operates at lower voltages, such as 110 kV or lower. Materials that can be treated with this lower voltage electron beam equipment (110 kV or lower) include coatings, inks, and laminating adhesives for flexible food packaging. One challenge facing those using electron beam processing for curing either overprint varnishes or laminating adhesives on conventional solvent or water-based inks is ink adhesion. Either the overprint varnish or the adhesive has little or no wettability or adhesion to the ink, or the ink itself lacks cohesiveness and can split or delaminate from the base film upon applying any force such as experienced during a standard T-peel test or tape adhesion test. Accordingly, there exists a need to continue developing materials that can be treated with EB processing. | <SOH> SUMMARY OF THE INVENTION <EOH>One embodiment of the present invention provides a layered material, e.g., a material having two or more layers. The material can be curable by exposure to highly accelerated particles, such as an electron beam. Further, the layered material can comprise: a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one monomer curable by free radical and/or cationic polymerization; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one monomer curable by free radical and/or cationic polymerization. Another embodiment of the present invention provides a layered material, comprising: a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols. Another embodiment of the present invention provides a layered material, comprising: a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one polymer derived from at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one polymer derived from at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols. Another embodiment of the present invention provides a layered material, comprising: a substrate; an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one first polymer; and a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one second polymer, wherein at least a portion of the at least one first polymer is bonded to at least a portion of the at least one second polymer. Another embodiment of the present invention provides a method for making a layered material, comprising: providing a substrate; applying an ink formulation on at least a portion of the substrate, the ink formulation comprising ink and at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols; and applying a lacquer on at least a portion of the ink formulation, the lacquer comprising at least one monomer selected from acrylate esters, vinyl ethers, cycloaliphatic diepoxides, and polyols. Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. | 20040414 | 20081111 | 20051020 | 63048.0 | 0 | SHEWAREGED, BETELHEM | MATERIALS TREATABLE BY PARTICLE BEAM PROCESSING APPARATUS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,823,948 | ACCEPTED | Method and apparatus for preventing a false pass of a cyclic redundancy check at a receiver during weak receiving conditions in a wireless communications system | At the receiver in a wireless communications system, the likelihood of a false CRC pass that can occur when a weak received signal produces an all ZERO output from a convolutional or a turbo decoder is minimized. To prevent an all ZERO output, a convolutional decoder selects from among those determined equally most likely transmitted sequences of bits in a data block one that has a weight greater than the one having the minimum weight. A turbo decoder selects a ONE rather than a ZERO as the value of a transmitted bit in a data block when for that bit a bit value of a ZERO and a ONE are determined to be equally likely. | 1. A method at a decoder comprising: selecting for output as each individual decoded bit in a block of bits from among all possible bits values, or a sequence of bits that comprise a block of bits from among all possible sequences of bits, the bit value or the sequence of bits, respectively, that is determined to have a maximum likelihood; characterized in that: for each individual bit in the block of bits when each possible bit value is determined to be equally likely for that bit, outputting from among each possible equally likely bit value the bit value whose weight is greater than the equally likely bit value whose weight is a minimum, and for a sequence of bits together in the block when more than one sequence is determined to have the same maximum likelihood, outputting the maximum likelihood sequence of bits whose weight is greater than the maximum likelihood sequence of bits that has the minimum weight. 2. The method of claim 1 wherein for each individual bit in the block the possible bit values are a ZERO and a ONE, and when for a bit they are both determined to be equally likely, a ONE is outputted. 3. The method of claim 1 wherein for the sequence of bits when more than one sequence is determined to have the same maximum likelihood, the maximum likelihood sequence outputted is the sequence having the largest weight. 4. The method of claim 1 wherein the method is performed at a decoder in a receiver in a wireless communications system. 5. The method of claim 4 wherein an all-ZERO decoder output is avoided in the presence of weak signal conditions. 6. A method at a decoder comprising: selecting for output as each individual decoded bit in a block of bits from among all possible bit values, or a sequence of bits together in a block of bit from among all possible sequences of bits, the bit value or the sequence of bits, respectively, that is determined to have a maximum likelihood; characterized in that: for each individual bit in the block of bits when each possible bit value is determined to be equally likely, randomly outputting one of the equally likely bit values, and for a sequence of bits when more than one sequence is determined to have the same maximum likelihood, randomly outputting one of the maximum likelihood sequences. 7. The method of claim 6 wherein for a sequence of bits, the randomly outputted sequence of bits is chosen from among the maximum likelihood sequences that excludes the maximum likelihood sequence that has the minimum weight. 8. The method of claim 6 wherein the method is performed at a decoder in a receiver in a wireless communications system. 9. The method of claim 8 wherein an all-ZERO decoder output is avoided with high probability in the presence of weak signal conditions. 10. A method at a decoder comprising: selecting for output for each decoded bit individually in a block of bits the bit value of a ZERO or a ONE that is determined to the most likely, characterized in that: when for each individual bit that a bit value of a ZERO and a ONE are determined to be equally likely, outputting the bit value of a ONE. 11. The method of claim 10 wherein the method is performed at a decoder in a receiver in a wireless communications system. 12. The method of claim 11 wherein an all-ZERO decoder output is avoided in the presence of weak signal conditions. 13. A method at a decoder comprising: selecting for output as a decoded sequence of bits in a block of bits from among all possible sequences of bits, the sequence of bits that is determined to have the maximum likelihood; characterized in that: when more than one sequence is determined to have the same maximum likelihood, outputting from among those maximum likelihood sequences the sequence whose weight is greater than the sequence having the minimum weight. 14. The method of claim 13 wherein the maximum likelihood sequence outputted is the one having the largest weight among the maximum likelihood sequences. 15. The method of claim 13 wherein the method is performed at a decoder in a receiver in a wireless communications system. 16. The method of claim 14 wherein an all-ZERO decoded sequence of bits is avoided in the presence of weak signal conditions. 17. Apparatus comprising: means for receiving set of soft symbol metric values representing a transmitted block of data bits; decoding means, in response to the received set of soft symbol metric values, for selecting for output as each individual decoded bit the bit that is determined to have a maximum likelihood, wherein when for a bit a ONE and ZERO are equally likely, a bit value of ONE is selected. 18. The apparatus of claim 17 wherein the decoding means is a turbo decoder. 19. Apparatus comprising: means for receiving a set of soft symbol metric values representing a transmitted block of data bits; decoding means, in response to the received set of soft symbol metric values, for selecting for output as a decoded sequence of bits from among all possible sequences of bits, the sequence of bits that is determined to have the maximum likelihood, wherein when more than one sequence is determined to have the same maximum likelihood, the sequence outputted is the maximum likelihood sequence whose weight is greater than the maximum likelihood sequence having the minimum weight. 20. The apparatus of claim 19 wherein the decoding means is a Viterbi decoder. | TECHNICAL FIELD This invention relates to wireless communications, and more particularly, to preventing the false pass of a Cyclic Redundancy Check (CRC) at a receiver when signal conditions are weak. BACKGROUND OF THE INVENTION 3GPP UMTS and 3GPP2 cdma2000-1x EVDO (or EVDO herein after) standards specify the use of convolutional and/or turbo coding as an error correction method to protect the transmitted data between a base station, referred to as NodeB in UMTS terminology, and a mobile terminal, referred to as user equipment (UE) in UMTS terminology. A CRC code is also applied as a measure of error detection to detect errors that cannot be corrected by the convolutional or turbo decoder to guarantee the integrity of a data block before reporting it to the higher layer. The CRC is defined by its generating polynomial and the initial state of the CRC generator. The current 3GPP UMTS/3GPP2 EVDO standards specify the initial state for the CRC generator to be all ZEROs. When receiving conditions are weak, meaning that the received signal strength has become insufficient to support the radio-like normal operations, problems can arise through this selection of an initial state causing a false pass to be generated for a block of data when it should otherwise really be a fail due to the inaccuracy of a detected block of bits. This can happen when the UE is in a soft handoff mode when one or more radio links are significantly weaker than others, or when the UE temporarily goes into a deep fade, but will exit the fade before the network can disable the radio link. In a receiver at either a NodeB or a UE, after a received Code Division Multiple Access (CDMA) signal is despread and demodulated, the output is a sequence of soft symbol metric values consisting of signed numeric values, which are inputted to either a convolutional decoder or a turbo decoder to determine the transmitted bit stream. In weak receiving conditions, each of the soft symbol metric values at the output of the demodulator are likely to have close to a zero value. In the convolutional decoder, in processing an input sequence of soft symbol metric values associated with a block of data, the likelihood of each possible transmitted bit sequence is calculated and the sequence with the largest likelihood is used to determine the transmitted sequence. When the received signal is weak and the soft symbol metric values are likely all close to a zero value, there is a high probability that multiple code sequences will have the same likelihood, which is also a maximum among all possible code sequences. Among these equal maximum likelihood sequences is always the all-ZERO sequence. The convolutional decoder picks the code sequence with the least weight so that in a weak signal condition, the all ZERO sequence is always chosen as having been the transmitted sequence. In the turbo decoder, in processing an input sequence of soft symbol metric values in a block of data, two likelihood values of each bit are calculated (one for bit value ZERO and the other for bit value ONE) and for each bit the bit value with the larger likelihood is outputted. When the received signal is weak and each soft symbol metric value is close to zero, there is a high probability that the two likelihood values for a bit are the same for all the bits in the data block. The decoder picks the bit value ZERO for each bit and thus produces an all-ZERO decoded bit stream for the block. In weak signal conditions, therefore, both the convolutional decoder and the turbo decoder produce an all-ZERO output sequence resulting in an all ZERO decoded bit stream consisting of blocks that have an all-ZERO data part and an all-ZERO CRC part, regardless of what actually has been transmitted. When the initial state for the CRC recalculation at the receiver is set to all ZEROs, an inputted all-ZERO data part for the CRC recalculation results in an all-ZERO CRC, which then matches the all-ZERO CRC part in the decoded block. A CRC pass is then declared for this data block regardless of the fact that the transmitted data has been totally corrupted by noise and/or interference. The result of this false pass can be significant. For voice calls, the receiver passes bad data (i.e., all ZEROs) to the vocoder, which can cause screech on the receiving end when the UE goes into deep fade for up to a 16 frame period (160 ms) before the network makes the decision to disconnect the radio link. For data calls, an all ZERO input can result in a hang-up of the connection, requiring the connection to be reset. Since the initial state of the CRC generator has been set by the standards to be ZERO and has been implemented in equipment already installed, the initial state of the CRC generator cannot be changed to avoid the problem. A solution is needed, therefore, to avoid false CRC-passes at a NodeB or UE receiver when receiving conditions are weak. SUMMARY OF THE INVENTION In accordance with an embodiment of the present invention, in determining the transmitted bits from input soft symbol metric values associated with a block of data on either a bit-by-bit basis, or on a sequence of bits basis, when on a bit-by-bit basis a ZERO or a ONE bit value are determined to be equally likely, or when on a sequence of bits basis more than one sequence of bits is determined to have a same maximum likelihood, a methodology is used other than always selecting ZERO as the transmitted bit value or selecting the sequence of bits that has the least weight. Thus, on a bit-by-bit basis as is performed by a turbo decoder, for example, a bit value of ONE is chosen as the transmitted bit value rather than a ZERO when both a ONE and a ZERO are determined to be equally likely. On a sequence of bits basis as is performed by a convolutional decoder such a Viterbi decoder, for example, when multiple sequences are determined to have a same maximum likelihood, rather than always selecting as the transmitted sequence the sequence whose weight is the smallest, a sequence whose weight is greater than the smallest is chosen, as for example, the sequence whose weight is the largest. By so changing the paradigm used to determine the transmitted bits by the turbo decoder and the transmitted bit sequence by the convolutional decoder in this manner, an input sequence of near zero-value soft symbol metrics caused by weak signal conditions will not produce an all ZERO decoded output bit sequence. Thus, when a CRC calculation and check is performed on this decoded output sequence, the CRC check will fail with high certainty, producing the desired CRC fail in the presence of a weak signal and the decoded sequence will not then be passed forward for further processing. In other embodiments, other methodologies can be used to break a tie of maximum likelihood values. For example, on a bit-by-bit basis, a bit can be chosen randomly when the determined likelihoods of a ZERO and a ONE are the same. On a sequence of bits basis, when multiple sequences are determined to have the same maximum likelihood, a random selection of the sequence of bits from among those with maximum likelihood can be chosen as the transmitted sequence either including or excluding the sequence with minimum weight. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a block diagram of a 3GPP UMTS/3GPP2 EVDO wireless communications system; FIG. 2 shows an example of an 8-bit CRC generator; FIG. 3 is a conceptual block diagram of a Viterbi decoder for an exemplary input block consisting of 10 data bits and 8 CRC bits; FIG. 4 is a flowchart of a prior art methodology used by the Viterbi decoder in FIG. 3 to determine an output sequence; FIG. 5 is a flowchart illustrating a decoding methodology for a Viterbi decoder of FIG. 3 in accordance with an embodiment of the present invention; FIG. 6 is a conceptual block diagram of a turbo decoder for an exemplary input block consisting of 10 data bits and 8 CRC bits; FIG. 7 is a flowchart or a prior art methodology used by the turbo decoder of FIG. 6 to determine an output sequence; and FIG. 8 is a flowchart illustrating a decoding methodology for a turbo decoder of FIG. 6 in accordance with an embodiment of the present invention. DETAILED DESCRIPTION With reference to FIG. 1, a high-level block diagram of a 3GPP UMTS/3GPP2 EVDO wireless communications system is shown. The transmitter 101 can be in the NodeB, which is transmitting downlink over propagation channel 102 to the receiver 103 in the UE. Alternatively, the transmitter 101 can be in the UE, which is transmitting uplink over the propagation channel 102 to the receiver 103 in the NodeB. At transmitter 101, a bit stream to be transmitted representing a coded voice signal or data is inputted to a CRC calculation and attachment device 104. The input bit stream consists of data block of, for example, 10 bits. As is well known in the art, CRC calculation and attachment device 104 using a predefined generating polynomial and predefined initial state generates a set of CRC bits, which are attached to the input block. For example, as will be detailed herein below, if an 8-bit CRC is calculated, those eight CRC bits are appended to the 10-bit input block to produce for that 10-bit input block, an output sequence of 18 bits B: {b0b1 . . . b17}. That 18-bit block B is inputted to an encoder 105 that uses one but not both of convolutional encoding and turbo encoding. A higher level of processing determines selection of the type of encoding based on various factors such as the type of data that the input block contains. That selection process is not relevant to the description of the embodiment of the present invention and will not be discussed further. If encoder 105 is assumed to be a half-rate encoder, the output consists of twice the number of input bits, or 36 bits for the example of an 18-bit input. The output of encoder 105 is inputted to a modulator 106, which for an exemplary BPSK modulator produces a set of symbols S: {s0s1 . . . s35} that corresponds to the ONEs and ZEROs in modulator's 36-bit input, where each input ZERO is converted to a symbol of +1 and each input ONE is converted to a symbol of −1. The set of symbols S at the output of modulator 106 is then inputted to a spreader 107, which performs CDMA spreading in a conventional manner for transmission over the propagation channel 102. At the receiver 103, a despreader 110 despreads the received CDMA signal and demodulator 111 demodulates the despread signal to produce the soft symbol metric values R: {r0r1 . . . r35}, where each symbol ri corresponds to a transmitted symbol si. Generally, the metric for each coded bit is in the format of a real number, with its sign representing whether it is a ZERO or a ONE, and the magnitude of the value representing how likely the sign is correct. The output of the demodulator 111 is inputted to a decoder 112, which takes its soft symbol metric value inputs and determines the most likely transmitted bits. As will be described, when the set of bits B {b0 . . . b18} are encoded by encoder 105 using a convolutional encoding, decoder 112 is a Viterbi decoder, which decodes the sequence B as a whole. When the bits B are encoded by encoder 105 using turbo encoding, decoder 112 is a turbo decoder, which decodes each bit in the sequence bit-by-bit. The decoded bit stream, consisting of a data block of 18 bits that includes a 10-bit data part and an 8-bit CRC part, is inputted to a CRC calculation and check device 113. Device 113 calculates a CRC from the 10-bit data part in the same manner that it was calculated by device 104 in the transmitter 101, and then compares the result with the received CRC part. If the calculated CRC matches the received CRC part, device 113 outputs a CRC Pass together with the data block. If the calculated CRC does not match the received CRC part, then a CRC Fail is declared and the data part is not passed forward. FIG. 2 shows a CRC generator 201 for an 8-bit CRC that uses an exemplary generating polynomial g(x)=x8+x7+x4+x3+x+1. Such a structure is well known to those skilled in the art and is readily configured based on the generating polynomial. Each of the eight storage units 202 stores one bit and each of the five adders 203 performs modulo-2 addition. As noted in FIG. 2, each storage unit represents xn for n=1 to n=8. At the transmitter 101 in FIG. 1, the 10 bits in an input data block in FIG. 2 are read in bit-by-bit on input 204 when switches 205 are each in their up positions. Thus, each input bit is directly fed to the output and is fed back to be combined with the previous bit stored in a storage unit where indicated. As previously noted, the initial state of the generator 201 is such that each storage unit initially contains a ZERO. After the 10 input bits have been sequentially clocked in and processed by the generator, switches 205 are moved to their down positions and the eight bits stored in the eight storage units 202 are clocked to the output 206, thereby being appended to the 10 input bits that preceded them and thereby forming the 18-bit input B to the encoder 105. The actual order of transmission of the CRC bits to the encoder is standards specific. In 3GPP UMTS, the first clocked CRC bit is the last and the last clocked CRC bit is the first to go into the encoder, while in 3GPP@EVDO, it is the reverse order. During this same 8-bit period, ZEROs are clocked into storage units 202 so that at the end of this 8-bit period each storage unit contains the desired initial ZERO state. With reference again to FIG. 1, at the receiver 103, the first 10 bits at the output of decoder 112 are inputted to a CRC generator 201 to produce an 8-bit output which is then compared with the last 8 bits of the decoder 112 output. At the receiver 103 a CRC Pass is declared only if there is agreement between both 8-bit sequences. As previously noted, the 3GPP standards specify that initial state of the CRC generator to be all-ZERO, i.e., a ZERO is initially set in each storage device 202. Thus, if at the receiver 103 all 18 bits at the output of decoder 112 are ZERO, generator 201 in FIG. 2 produces an 8-bit all-ZERO CRC, which matches the 8-bit all-ZERO CRC bits within the 18-bit output of decoder 112. As a result, a Pass is given to the 10-bit all-ZERO data. As previously noted, this is problematic because, as will be described in detail below, in the prior art, decoder 112 produces an all-ZERO decoded bit stream when the received signal is weak, regardless of what has been transmitted by the transmitted. Thus, a false Pass is generated when what really is desired is a CRC Fail under such weak signal conditions where the received data is in error. As afore noted, if the encoder 105 is a convolutional encoder, the decoder 112 is a Viterbi decoder, which is a maximum likelihood sequence detector, i.e., it selects the code sequence that has the largest likelihood. Since a one-to-one mapping exists between the uncoded bit stream at the input to the encoder 105 and the coded sequence at the output of the encoder, the decoder 112 can perform an inverse mapping once the code sequence with the maximum likelihood is chosen. The output of the inverse mapping is the Viterbi decoder output. A conceptual block diagram of a Viterbi decoder for the exemplary 10-bit data, 8-bit CRC, total 18-bit input is shown in FIG. 3. Since there are only 10-bits of data, there are 210 possible bit streams that can be transmitted by the transmitter since the 8-bit CRC part is directly dependent on the bits in the data part once the CRC polynomial and generator initial state are given. In FIG. 3, the soft symbol metric R: {r0 . . . r35) at the output of the demodulator 111 in FIG. 1 is inputted to calculating device 301, which calculates the likelihood of each possible code sequence. Since the Viterbi decoder assumes no CRC structure, there are 218 possible transmitted sequences. Thus, calculating device 301 calculates the likelihood for each and every one of the 218 (262,144) sequences. The likelihood that a particular input sequence has been transmitted is equal (with a constant scaling factor) to the exponential of the inner product of the corresponding coded sequence at the output of the modulator and the input of input soft bit metric sequence. Selector 302 chooses the sequence with the largest likelihood and inverse mapper 303 performs an inverse mapping on the selected sequence to produce the decoder output. FIG. 4 is a flowchart of the prior art methodology used by the Viterbi decoder in FIG. 3 to determine an output sequence. At step 401, the soft symbol metric values for a data block are read in. At step 402, the likelihood for each possible coded sequence is calculated from these soft symbol metric values. At step 403, these coded sequences are sorted in descending order by their calculated likelihood. At step 404, those sequences whose likelihood values are not the maximum are eliminated. At step 405, a determination is made whether there exists more than one sequence whose likelihood is a maximum. If only one such sequence exists, then, at step 406, the decoder outputs that sequence. If more than one sequence exists that has the same maximum likelihood, then, at step 407, the weight for each of such sequences is calculated, where weight is equal to the count of non-zero-valued bits in the sequence. At step 408, sequences whose weights are not the smallest are eliminated. At step 409, a determination is made whether there exists only one such sequence with the smallest weight. If only one such sequence exists with a smallest weight, then, at step 410, the decoder outputs this sequence. If more than one sequence exists whose weight is the smallest, then, at step 411, the decoder outputs the sequence amongst those whose first differing most significant bit (MSB) from any other of these sequences is a ZERO. As previously described, the problem with this methodology is that when then the received signal is weak, there is a high probability that multiple code sequences will have the same maximum likelihood. The all-ZERO sequence will always be among those sequences having that same maximum likelihood. Since the all-ZERO sequence has a zero weight (the number of non-zero bits equals zero), the all-ZERO sequence is the sequence that is selected and outputted. The all-ZERO sequence, with 10 ZERO data bits and 8 ZERO CRC bits results in a CRC Pass regardless of what bit stream has actually been sent by the transmitter, and not a CRC Fail, which is what is desired under such weak signal conditions where the received signal is in error. FIG. 5 illustrates a decoding methodology in accordance with an embodiment of the present invention that avoids this problem. At step 501, the soft symbol metrics for a data block are read in. As before, at step 502, the likelihood for each possible coded sequence is calculated from the read-in soft symbol metrics. As before, at step 503, these sequences are sorted in descending order by their calculated likelihood. As before, at step 504, those sequences whose likelihood is not the maximum are eliminated. As before, at step 505, a determination is made whether there exists more than one sequence whose likelihood is a maximum. If only one such sequence exists, then, at step 506, the decoder outputs that sequence. As before, if more than one sequence exists that has the same maximum likelihood, at step 507, the weight for each of such sequence is calculated. At step 508, however, sequences whose weights are not the largest are eliminated. At step 509, a determination is made whether there exists only one such sequence with the largest weight. If only one such sequence exists with a largest weight, then, at step 510, the decoder outputs this sequence. If more than one sequence exists whose weight is the largest, at step 511, the decoder outputs the sequence amongst those whose first differing MSB from any other of these sequences is a ONE. With this methodology, since the all-ZERO sequence will always be the sequence that has the smallest weight amongst those sequences whose likelihood is the maximum, the decoder will output another of those sequences, specifically the one whose weight is the largest. When a CRC is performed on the data portion of this selected sequence, with high probability the calculated CRC will not match the 8-bit CRC portion of the selected. Thus, for the weak signal condition, the desired CRC Fail results. Although the above-described embodiment at step 508 eliminates sequences whose weight are not the largest, other embodiments could achieve the same advantages by selecting any sequence to output from among those with the maximum likelihood whose weight is greater than the maximum likelihood sequence whose weight is the minimum. The selected sequence will thus be one that produces the desired CRC fail with high probability. Alternatively, a tie in likelihood values could be broken by randomly picking a sequence from among all the multiple sequences with equal maximum likelihoods, or from among the multiple sequences with equal maximum likelihoods excluding the sequence with minimum weight. Although described in conjunction with a convolutional coder and convolutional Viterbi decoder, the same principles could be applied to any other coder that codes blocks of data and a decoder that decodes those blocks based on determined likelihoods, such as, for example, a block coder and block decoder, known in the art. When a turbo encoder is used to encode the 18-bit data block, a turbo decoder is used to decode the received turbo code. The turbo decoder is an approximation of maximum likelihood bit detection in that it calculates the likelihood of each individual bit based on the input soft symbol metric sequence values. Since each bit has two possible values, a ZERO and a ONE, there are two likelihood values for each bit, namely the likelihood that a bit has a value ZERO and the likelihood that the bit has a value ONE. The decoder chooses the value for each bit that gives a larger likelihood. The likelihood that bit i has a bit value of ZERO, for any i=0 to i=17, is equal (with a constant scaling factor) to the sum of the exponential of each and every inner-product of: (every code sequence at the output of the modulator that has bit i=ZERO) and (the input soft symbol metric sequence). Similarly, the likelihood that bit i has a bit value of ONE, for any i=0 to i=17, is equal (with a constant scaling factor) to the sum of the exponential of each and every inner-product of: (every code sequence at the output of the modulator that has bit i=ONE) and (the input soft symbol metric sequence). FIG. 6 is a block diagram showing the architecture of a turbo decoder 601 for an exemplary input block consisting of 10 data bits and 8 CRC bits. As noted above, since the 8 CRC bits are decided by the 10 data bits, there are only 210 possible bit streams that can be transmitted. The turbo decoder 601, however, assumes no CRC structure so that from the decoder's point of view there are 218 possible received sequences. Calculating device 602 thus calculates the likelihood for each of the 18 bits from the soft symbol metric values on input 603. Thus, as noted in FIG. 6, the likelihood that bit i=0 and bit i=1 is calculated for each i, for i=0 to i=17 by calculating device 602. Comparator devices 604 then select the bit value with the larger likelihood for each of the 18 bits, which are outputted on outputs 605. When the received signal is weak, there is a high probability that the two likelihood values for a bit are the same for all the bits in the data block. FIG. 7 is a block diagram of the turbo decoder processing performed by the turbo decoder of FIG. 6 in the prior art. At step 701, the soft symbol metric values are read in. At step 702, the likelihoods for each bit being a ZERO and a ONE are calculated. At step 703, a pair of likelihood values for a bit is read in, starting with the MSB. At step 704, a determination is made whether for a bit, the two likelihood values are equal. If not, at step 705, the bit value that gives the larger likelihood value is selected. If, at step 704, the two likelihood values are equal, then, at step 706, a bit value of ZERO is decided upon. At step 707, regardless of what bit value had been decided upon, a determination is made whether all the bits in the data have been processed. If yes, then processing of the data block is done. If not, the next pair of likelihood values for the next bit is read in and the process repeats until all bits have been processed. Thus, when the signal is weak, and the two likelihood values for a bit are the same, the decoder produces an all-ZERO decoded bit stream. As previously described, this results in a CRC check Pass, regardless of the bit stream actually transmitted. FIG. 8 is a flowchart of the turbo decoder processing performed by an embodiment of a turbo decoder in accordance with an embodiment of the present invention. As before, at step 801, the soft symbol metric values are read in. As before, at step 802, the likelihoods for each bit value being a ZERO and a ONE are calculated. As before, at step 803, a pair of likelihood values for a bit is read in, starting with the MSB. As before, at step 804, a determination is made whether for a bit, the two likelihood values are equal. As before, if not, at step 805, the bit value that gives the larger likelihood value is decided upon. However; if, at step 804, the two likelihood values are equal, then, at step 806, a bit value of ONE is decided upon. At step 807, regardless of what bit value had been decided upon, a determination is made whether all the bits in the data have been processed. If yes, then processing of the data block is done. If not, the next pair of likelihood values for the next bit is read in. Thus, when the signal is weak, and the two likelihood values for a bit are the same, the decoder produces an all-ONE decoded bit stream. When the CRC check is performed on this all-ONE data block, a CRC check Fail results instead of a CRC check Pass, thus preventing passing on of the unreliable data block for further processing. In an alternative embodiment, when the likelihood values of a bit for a ONE and ZERO are determined to be equal, the bit value can be randomly selected. Since the probability of randomly selecting all bits to be ZERO is ½18 for an 18-bit sequence, it would be highly unlikely to produce the all ZERO sequence that would result in a CRC pass. While the particular invention has been described with reference to the illustrative embodiment, this description should not be construed in a limiting sense. It is understood that although the present invention has been described, various modifications of the illustrative embodiments, as well as additional embodiments of the invention, will be apparent to one of ordinary skill in the art upon reference to this description without departing from the spirit of the invention, as recited in the claims appended hereto. Further, the invention may be implemented in different locations, such as at a mobile terminal (UE), a base station (NodeB); a base station controller (in UMTS terminology, a Radio Network Controller [RNC]) and/or a mobile switching center (in UMTS terminology, a mobile service switching center [MSC]), or elsewhere depending upon in what type of system the invention is employed. Moreover, processing circuitry required to implement and use the described invention may be implemented in application specific integrated circuits, software-driven processing circuitry, firmware, programmable logic devices, hardware, discrete components or arrangements of the above components as would be understood by one of ordinary skill in the art with the benefit of this disclosure. Those skilled in the art will readily recognize that these and various other modifications, arrangements and methods can be made to the present invention without strictly following the exemplary applications illustrated and described herein and without departing from the spirit and scope of the present invention. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>3GPP UMTS and 3GPP2 cdma2000-1x EVDO (or EVDO herein after) standards specify the use of convolutional and/or turbo coding as an error correction method to protect the transmitted data between a base station, referred to as NodeB in UMTS terminology, and a mobile terminal, referred to as user equipment (UE) in UMTS terminology. A CRC code is also applied as a measure of error detection to detect errors that cannot be corrected by the convolutional or turbo decoder to guarantee the integrity of a data block before reporting it to the higher layer. The CRC is defined by its generating polynomial and the initial state of the CRC generator. The current 3GPP UMTS/3GPP2 EVDO standards specify the initial state for the CRC generator to be all ZEROs. When receiving conditions are weak, meaning that the received signal strength has become insufficient to support the radio-like normal operations, problems can arise through this selection of an initial state causing a false pass to be generated for a block of data when it should otherwise really be a fail due to the inaccuracy of a detected block of bits. This can happen when the UE is in a soft handoff mode when one or more radio links are significantly weaker than others, or when the UE temporarily goes into a deep fade, but will exit the fade before the network can disable the radio link. In a receiver at either a NodeB or a UE, after a received Code Division Multiple Access (CDMA) signal is despread and demodulated, the output is a sequence of soft symbol metric values consisting of signed numeric values, which are inputted to either a convolutional decoder or a turbo decoder to determine the transmitted bit stream. In weak receiving conditions, each of the soft symbol metric values at the output of the demodulator are likely to have close to a zero value. In the convolutional decoder, in processing an input sequence of soft symbol metric values associated with a block of data, the likelihood of each possible transmitted bit sequence is calculated and the sequence with the largest likelihood is used to determine the transmitted sequence. When the received signal is weak and the soft symbol metric values are likely all close to a zero value, there is a high probability that multiple code sequences will have the same likelihood, which is also a maximum among all possible code sequences. Among these equal maximum likelihood sequences is always the all-ZERO sequence. The convolutional decoder picks the code sequence with the least weight so that in a weak signal condition, the all ZERO sequence is always chosen as having been the transmitted sequence. In the turbo decoder, in processing an input sequence of soft symbol metric values in a block of data, two likelihood values of each bit are calculated (one for bit value ZERO and the other for bit value ONE) and for each bit the bit value with the larger likelihood is outputted. When the received signal is weak and each soft symbol metric value is close to zero, there is a high probability that the two likelihood values for a bit are the same for all the bits in the data block. The decoder picks the bit value ZERO for each bit and thus produces an all-ZERO decoded bit stream for the block. In weak signal conditions, therefore, both the convolutional decoder and the turbo decoder produce an all-ZERO output sequence resulting in an all ZERO decoded bit stream consisting of blocks that have an all-ZERO data part and an all-ZERO CRC part, regardless of what actually has been transmitted. When the initial state for the CRC recalculation at the receiver is set to all ZEROs, an inputted all-ZERO data part for the CRC recalculation results in an all-ZERO CRC, which then matches the all-ZERO CRC part in the decoded block. A CRC pass is then declared for this data block regardless of the fact that the transmitted data has been totally corrupted by noise and/or interference. The result of this false pass can be significant. For voice calls, the receiver passes bad data (i.e., all ZEROs) to the vocoder, which can cause screech on the receiving end when the UE goes into deep fade for up to a 16 frame period (160 ms) before the network makes the decision to disconnect the radio link. For data calls, an all ZERO input can result in a hang-up of the connection, requiring the connection to be reset. Since the initial state of the CRC generator has been set by the standards to be ZERO and has been implemented in equipment already installed, the initial state of the CRC generator cannot be changed to avoid the problem. A solution is needed, therefore, to avoid false CRC-passes at a NodeB or UE receiver when receiving conditions are weak. | <SOH> SUMMARY OF THE INVENTION <EOH>In accordance with an embodiment of the present invention, in determining the transmitted bits from input soft symbol metric values associated with a block of data on either a bit-by-bit basis, or on a sequence of bits basis, when on a bit-by-bit basis a ZERO or a ONE bit value are determined to be equally likely, or when on a sequence of bits basis more than one sequence of bits is determined to have a same maximum likelihood, a methodology is used other than always selecting ZERO as the transmitted bit value or selecting the sequence of bits that has the least weight. Thus, on a bit-by-bit basis as is performed by a turbo decoder, for example, a bit value of ONE is chosen as the transmitted bit value rather than a ZERO when both a ONE and a ZERO are determined to be equally likely. On a sequence of bits basis as is performed by a convolutional decoder such a Viterbi decoder, for example, when multiple sequences are determined to have a same maximum likelihood, rather than always selecting as the transmitted sequence the sequence whose weight is the smallest, a sequence whose weight is greater than the smallest is chosen, as for example, the sequence whose weight is the largest. By so changing the paradigm used to determine the transmitted bits by the turbo decoder and the transmitted bit sequence by the convolutional decoder in this manner, an input sequence of near zero-value soft symbol metrics caused by weak signal conditions will not produce an all ZERO decoded output bit sequence. Thus, when a CRC calculation and check is performed on this decoded output sequence, the CRC check will fail with high certainty, producing the desired CRC fail in the presence of a weak signal and the decoded sequence will not then be passed forward for further processing. In other embodiments, other methodologies can be used to break a tie of maximum likelihood values. For example, on a bit-by-bit basis, a bit can be chosen randomly when the determined likelihoods of a ZERO and a ONE are the same. On a sequence of bits basis, when multiple sequences are determined to have the same maximum likelihood, a random selection of the sequence of bits from among those with maximum likelihood can be chosen as the transmitted sequence either including or excluding the sequence with minimum weight. | 20040414 | 20080624 | 20051020 | 65140.0 | 0 | BAKER, STEPHEN M | METHOD AND APPARATUS FOR PREVENTING A FALSE PASS OF A CYCLIC REDUNDANCY CHECK AT A RECEIVER DURING WEAK RECEIVING CONDITIONS IN A WIRELESS COMMUNICATIONS SYSTEM | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,823,977 | ACCEPTED | Method and system to backscatter modulate a radio-frequency signal from an RFID tag in accordance with both an oscillation frequency signal and a command signal | According to one aspect of the present invention, there is provided a method to backscatter modulate a first radio-frequency (RF) signal from a radio-frequency identification (RFID) tag. An oscillator calibration value is retrieved from a non-volatile memory associated with the RFID tag. An oscillation frequency signal is generated within the RFID tag, the generating of the oscillation signal being performed utilizing the oscillator calibration value. A command signal is generated within the RFID tag, the command signal being based on command data received at the RFID tag in a second radio-frequency signal from an RFID reader. The first radio-frequency signal is backscatter modulated in accordance with both the oscillation frequency signal and the command signal. | 1. A radio-frequency identification (RFID) tag including: a non-volatile memory; an oscillator, coupled to the non-volatile memory, to receive an oscillator calibration value from the non-volatile memory, and to generate an oscillation frequency signal within the RFID tag utilizing the oscillator calibration value; a tag controller to generate a command signal within the RFID tag, the command signal being based on command data received at the RFID tag in a received radio-frequency signal from an RFID reader; and a modulator to backscatter modulate a transmitted radio-frequency signal in accordance with both the oscillation frequency signal and the command signal. 2. The tag of claim 1, wherein the tag controller is to receive the oscillator calibration value in association with a write command at the RFID tag, and to write the oscillator calibration value to the non-volatile memory responsive to the write command. 3. The tag of claim 2, wherein the write command is received via a test signal supplied to an RFID integrated circuit of the RFID tag. 4. The tag of claim 2, wherein the write command is received within via a further radio-frequency signal supplied to the RFID tag by the RFID reader. 5. The tag of claim 1, wherein the oscillation frequency signal comprises a clock signal recovered from the received radio-frequency signal. 6. The tag of claim 1, wherein the command data is included within a protocol communication received at the RFID tag from the RFID reader. 7. The tag of claim 6, wherein the command data specifies a backscatter rate applicable to the first radio-frequency signal. 8. The tag of claim 6, including a demodulator to demodulate the received radio-frequency signal received from the RFID reader, to extract the command data therefrom, and to communicate the command data to a command decoder of the tag controller. 9. The tag of claim 6, wherein the command decoder is to communicate a command, corresponding to the command data, to a tag state machine of the tag controller, the tag state machine to generate the command signal. 10. The tag of claim 1, wherein the tag controller is to provide the command signal to a clock generation circuit so as to control a frequency of a modulation clock signal provided by the clock generation circuit to the modulator of the RFID tag. 11. The tag of claim 1, wherein the tag controller is to provide the command signal to the modulator of the RFID tag so as to control modulation of the first radio-frequency signal. 12. The tag of claim 1, wherein the tag controller is to select the oscillator calibration value, from one of a plurality of oscillator calibration values stored within the non-volatile memory, to be received by the oscillator. 13. The tag of claim 1, wherein the tag is to store the oscillator calibration value within the non-volatile memory responsive to a programming operation. 14. The tag of claim 13, wherein the programming operation includes providing a command and an associated update value to the RFID tag 15. The tag of claim 13, wherein the programming operation is performed as part of a test operation with respect to an RFID circuit of the RFID tag. 16. A method to backscatter modulate a first radio-frequency signal from a radio-frequency identification (RFID) tag, the method including: retrieving an oscillator calibration value from a non-volatile memory associated with the RFID tag; generating an oscillation frequency signal within an RFID tag, the generating of the oscillation frequency signal being performed utilizing the oscillator calibration value; generating a command signal within the RFID tag, the command signal being based on command data received at the RFID tag in a second radio-frequency signal from an RFID reader; and backscatter modulating the first radio-frequency signal in accordance with both the oscillation frequency signal and the command signal. 17. The method of claim 16, including receiving the oscillator calibration value in association with a write command at the RFID tag, and writing the oscillator calibration value to the non-volatile memory responsive to the write command. 18. The method of claim 17, wherein the write command is received via a test signal supplied to an RFID integrated circuit of the RFID tag. 19. The method of claim 17, wherein the write command is received within via a third radio-frequency signal supplied to the RFID tag by the RFID reader. 20. The method of claim 16, wherein the oscillation frequency signal comprises a clock signal recovered from the second radio-frequency signal received from the RFID reader. 21. The method of claim 16, wherein the command data is included within a protocol communication received at the RFID tag from the RFID reader. 22. The method of claim 21, wherein the command data specifies a backscatter rate applicable to the first radio-frequency signal. 23. The method of claim 21, including demodulating the second radio-frequency signal received from the RFID reader to extract the command data therefrom, and communicating the command data to a command decoder within the RFID tag. 24. The method of claim 21, including communicating a command, corresponding to the command data, from the command decoder to a tag state machine, the tag state machine to generate the command signal. 25. The method of claim 16, wherein the command signal is provided to a clock generation circuit so as to control a frequency of a modulation clock signal provided by the clock generation circuit to a modulator of the RFID tag. 26. The method of claim 16, wherein the command signal is provided to a modulator of the RFID tag so as to control modulation of the first radio-frequency signal. 27. The method of claim 16, wherein the retrieving of the oscillator calibration value from the non-volatile memory includes selecting the oscillator calibration value from one of a plurality of oscillator calibration values stored within the non-volatile memory. 28. The method of claim 16, including storing the calibration value within the non-volatile memory utilizing a programming operation. 29. The method of claim 28, wherein the programming operation includes providing a command and an associated update value to the RFID circuit. 30. The method of claim 28, wherein the programming operation is performed as part of a test operation with respect to the RFID circuit. 31. A radio-frequency identification (RFID) tag including: a non-volatile memory means; first means, coupled to the non-volatile memory means, for receiving an oscillator calibration value from the non-volatile memory, and for generating an oscillation frequency signal within the RFID tag utilizing the oscillator calibration value; second means for generating a command signal within the RFID tag, the command signal being based on command data received at the RFID tag in a received radio-frequency signal from an RFID reader; and third means for backscatter modulating a transmitted radio-frequency signal in accordance with both the oscillation frequency signal and the command signal. 32. The tag of claim 31, wherein the second means is for receiving the oscillator calibration value in association with a write command at the RFID tag, and for writing the oscillator calibration value to the non-volatile memory means responsive to the write command. 33. A machine-readable medium storing a description of a circuit, said circuit comprising: an oscillator, operatively to be coupled to a non-volatile memory, to receive an oscillator calibration value from the non-volatile memory, and to generate an oscillation frequency signal within an RFID tag utilizing the oscillator calibration value; a tag controller to generate a command signal within the RFID tag, the command signal being based on command data received at the RFID tag in a received radio-frequency frequency signal from an RFID reader; and a modulator to backscatter modulate a transmitted radio-frequency signal in accordance with both the oscillation frequency signal and the command signal. 34. The machine-readable medium of claim 33, wherein the description comprises a behavioral level description of the circuit. 35. The machine-readable medium of claim 34, wherein the behavioral level description is compatible with a VHDL format. 36. The machine-readable medium of claim 34, wherein the behavioral level description is compatible with a Verilog format. 37. The machine-readable medium of claim 33, wherein the description comprises a register transfer level netlist. 38. The machine-readable medium of claim 33, wherein the description comprises a transistor level netlist. | FIELD OF THE INVENTION An embodiment relates generally to the field of oscillator calibration and, more specifically, to an apparatus and a method to calibrate an oscillator for a radio-frequency identification (RFID) system. BACKGROUND OF THE INVENTION Radio-frequency identification tags (or transponders) require a reference frequency for a number of purposes. An RFID reader transmits RF power to RFID tags. RFID tags modulate reflected RF power to transmit data back to an RFID reader. The reflected RF is called ‘backscatter,’ and the link from the tag back to the reader is typically referred to as the ‘backscatter link. The backscatter modulation of course requires a backscatter frequency to which the relevant RFID reader is sensitive. Furthermore, backscatter communications may be subject to regulatory restrictions, and may need to be compliant with one or more RFID communications specifications or standards. An RFID tag also requires a demodulation frequency so as to enable a demodulator within the RFID tag to demodulate received radio-frequency signals, and decode data contained therein. RFID tags also need to generate internal clock signals to clock various functional units that may be included within the RFID tag. With a view to generating the above-identified frequency and clock signals within an RFID tag, the RFID tag is typically equipped with an oscillator that generates the reference frequency. Three prior art mechanisms for providing such a reference frequency are discussed below. FIG. 1 is a schematic illustration of a first prior art oscillator arrangement 10 in which an oscillator 12 is coupled to a crystal 14 in order to provide a precise local reference frequency. Alternatively, the oscillator 12 may be coupled to an L-C tank or electron mobility-based reference in order to provide the precise local reference frequency. A disadvantage of such arrangements is that they tend to be bulky, and high-power consumers. A second manner in which it is known to provide a reference frequency within an RFID chip is to provide a phase-locked loop (PLL) arrangement, such as that illustrated by the schematic diagram of FIG. 2. Specifically, the phase-locked loop arrangement 16 of FIG. 2 is shown to include a phase detector 18 that is coupled to receive a reference frequency 20 and the oscillator output, compare them, and to provide a reference signal 22 to an oscillator 24. The disadvantages of the phase-locked loop arrangement 16 shown in FIG. 2 include the required provision of a reference frequency, a long start-up time, the provision of extra power for the phase detector 18, as well as the extra chip area requirements for provision of the phase detector 18. A similar function can also be done with a frequency detector, and a frequency-locked loop. A third prior art arrangement 26 to provide a reference frequency within an RFID tag is illustrated by the schematic diagram of FIG. 3. Specifically, a trimming arrangement 28 comprising a combination of resistors, capacitors and inductors (or fuses or resistors that may be laser-cut) provide a reference signal 22 (e.g., a current reference signal Iref) to an oscillator 30. Among the disadvantages of this arrangement are that the trimming arrangement may be expensive to build, and the configuration of the trimming arrangement 28 is permanent (i.e., the oscillator 30 cannot be dynamically calibrated). FIGS. 4 and 5 are diagrammatic representations of a prior art RFID system 32 including an RFID tag 34 that is interrogated by, and responds to, an RFID reader 36 utilizing a radio-frequency forward link and a backscatter return link. The RFID tag 34 is shown to provide a signal received from the RFID reader 36, via the radio-frequency forward link, to a demodulator 38, which recovers a timing (or clock) signal 40. The recovered clock signal 40 is utilized to generate a digital calibration value 44, which is stored in a volatile register 42. The volatile register 42 in turn provides the digital calibration value 44 to a digitally-controlled oscillator (DCO) 46. The digitally-controlled oscillator 46 outputs a demodulator clock signal 48. FIG. 5 illustrates the oscillator 46 of the RFID tag 32, again calibrated utilizing a digital calibration value 44 provided to the oscillator 46 from the volatile register 42. The oscillator 46 generates a modulator clock signal 52 to a modulator 50, the modulator 50 utilizing the modulator clock signal 52 to backscatter modulate communications transmitted via the backscatter return link to the RFID reader 36. In summary, it will be appreciated that, on start-up, the RFID reader 36 sends a radio-frequency forward link signal to the RFID tag 34, which extracts a timing (or clock) signal 40 from the received signal to calibrate the oscillator 46, this recovered timing signal 40 being communicated to the oscillator 46 via the register 42. During backscatter communications, the calibration is held by the oscillator 46, which is in turn utilized to drive the modulator 50. Accordingly, in the prior art system shown in FIGS. 4 and 5, the recovered timing signal 40 is stored within a volatile register that is utilized to calibrate the oscillator. However, a clock recovery operation is required by the demodulator 38 upon each power-up event, which may negatively impact the performance of the RFID tag 32. U.S. Pat. No. 5,583,819, entitled “Apparatus and Method of Use of Radiofrequency Identification Tags”, to Bruce B. Roesner and Ronald M. Ames, discloses an RFID tag in which a reference signal is initially generated by comparing an incoming standard signal, and placing it in a temporary or permanent storage within the RFID tag. Signals arriving later are then compared to the captured standard, and variations from the captured standards are detected to allow for decoding of the data. Specifically, a microprocessor is described as providing a correction signal to a memory, the correction signal then being stored within the memory as a correction value for use in subsequent operation of the RFID tag, or at least until the correction value is updated. The memory is described as possibly being a non-volatile memory to allow calibration information to be permanently stored, so that reconfiguration of the internal oscillator is not required each time the RFID tag is powered up. In the system described by Roesner, the calibration of the oscillator is nonetheless dependent upon an initial extraction or recovery of timing from a received radio-frequency signal. SUMMARY OF THE INVENTION According to one aspect of the present invention, there is provided a method to backscatter modulate a first radio-frequency (RF) signal from a radio-frequency identification (RFID) tag. An oscillator calibration value is retrieved from a non-volatile memory associated with the RFID tag. An oscillation frequency signal is generated within the RFID tag, the generating of the oscillation signal being performed utilizing the oscillator calibration value. A command signal is generated within the RFID tag, the command signal being based on command data received at the RFID tag in a second radio-frequency signal from an RFID reader. The first radio-frequency signal is backscatter modulated in accordance with both the oscillation frequency signal and the command signal. Other features of the present invention will be apparent from the accompanying drawings and from the detailed description that follows. BRIEF DESCRIPTION OF THE DRAWINGS The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which: FIG. 1 is a schematic illustration of a first prior art oscillator arrangement in which an oscillator is coupled to a crystal in order to provide a precise local reference frequency. FIG. 2 is a schematic illustration of a phase-locked loop arrangement that includes a phase detector coupled to receive a reference frequency and the oscillator output, to compare them, and to provide a reference signal to an oscillator. FIG. 3 is a schematic illustration of a prior art trimming arrangement to provide a reference frequency within an RFID tag. FIGS. 4 and 5 are diagrammatic representations of a prior art RFID system including an RFID tag that is interrogated by, and responds to, an RFID reader utilizing a radio-frequency forward link and a backscatter return link. FIG. 6 is a block diagram illustrating multiple operation types that may be performed by a radio-frequency identification (RFID) integrated circuit (IC) suitable for use within an RFID tag assembly. FIGS. 7A, 7B, 8A, and 8B are block diagrams providing high-level depictions of systems, in which one or more calibration values may be provided to an RFID integrated circuit, and written into a non-volatile memory associated with such an RFID integrated circuit. FIG. 9 is a block diagram illustrating an RFID tag, according to an exemplary embodiment of the present invention, that includes one or more antennae coupled to an RFID integrated circuit. FIG. 10 is a diagrammatic representation of an RFID tag, according to a further exemplary embodiment of the present invention, which again includes one or more antennae and an RFID integrated circuit. FIG. 11 is a diagrammatic representative of yet a further exemplary embodiment of an RFID tag, according to an exemplary embodiment of the present invention. FIG. 12 is a diagrammatic representation of an RFID tag, according to one further exemplary embodiment of the present invention, wherein clock generation circuitry of an RFID integrated circuit includes a voltage-controlled oscillator (VCO). FIG. 13 is a flowchart illustrating a method, according to an exemplary embodiment of the present invention, to program calibration of an oscillator within a radio-frequency identification (RFID) integrated circuit for use in a RFID tag. FIG. 14 is a flowchart illustrating a method, according to a further embodiment of the present invention, to program calibration of an oscillator within a radio-frequency identification (RFID) integrated circuit, using a test device. FIG. 15 is a flowchart illustrating a method, according to an exemplary embodiment of the present invention, to calibrate an oscillator within a radio-frequency identification (RFID) circuit that may form part of an RFID tag, and to generate various clock signals within the RFID circuit in accordance with an output of the oscillator. FIGS. 16-24 are diagrammatic representation providing high-level representations of various exemplary embodiments of the present invention. FIG. 25 is a schematic diagram illustrating a portion of exemplary clock generation circuitry including a core oscillator, and a calibration module. DETAILED DESCRIPTION A calibrated oscillator for an RFID system, and methods of manufacturing and operating the same, are described. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be evident, however, to one skilled in the art that the present invention may be practiced without these specific details. FIG. 6 is a block diagram illustrating multiple operation types 60 that may be performed by a radio-frequency identification (RFID) integrated circuit (IC) suitable for use within an RFID tag assembly. In an exemplary embodiment, an RFID tag may be a combination of an RFID circuit (e.g., an Integrated Circuit (IC)), and a coupled antenna (or antennae) to facilitate the reception and transmission of radio-frequency signals, the RFID circuit and the antenna(e) being located on a base material or substrate (e.g., a plastic or paper material) to thereby constitute an RFID tag. As shown in FIG. 6, according to one aspect of the present invention, an RFID integrated circuit may be subject to a programming operation 62, in which one or more calibration values are stored within a non-volatile memory (e.g., a floating-gate MOSFET non-volatile memory). The storage of the calibration values may be performed, for example, to facilitate calibration of an oscillator included within the RFID integrated circuit (in accordance with the one or more calibration values) in advance of an interrogation operation 64. In one embodiment, each calibration value is a delta value according to which the oscillation of the oscillator, within the RFID integrated circuit, is modified. Various exemplary methods by which a calibration values may be written to the non-volatile memory, while an RFID integrated circuit is performing a programming operation 62, are described below. FIG. 6 also illustrates that an RFID integrated circuit may perform an interrogation operation 64, during which the RFID integrated circuit receives a request from an RFID reader, and then retrieves (or generates) reply information, which is encoded in a backscatter modulated radio-frequency signal transmitted from the RFID tag back to the RFID reader. The backscatter modulation is performed utilizing the one or more calibration values stored within the non-volatile memory. The data included within the backscatter modulated radio-frequency signal may include, for example, one or more identification codes (e.g., an Electronic Product Code (EPC)) stored in a memory of the RFID tag. A number of exemplary embodiments of methods by which such backscatter modulation may be achieved, and by which various oscillation frequencies and clock signals may be generated within an RFID integrated circuit, are discussed below. Dealing first with examples of programming operations 62, FIGS. 7A, 7B, 8A, and 8B are block diagrams providing high-level depictions of systems 66 and 67, by which one or more calibration values may be provided to an RFID integrated circuit, and written into a non-volatile memory associated with such an RFID integrated circuit. Specifically, a test system 66 shown in FIG. 7A includes an RFID integrated circuit test device 68 that is coupled to an RFID integrated circuit 70 so as to enable the test device 68 to provide a test signal to the RFID integrated circuit 70. To this end, the RFID integrated circuit 70 includes a suitable interface (not shown) to receive the test signal from the test device 68. The test device 68 may be any one of a number of test devices (e.g., a wafer testing device, a die testing device, or an individual IC testing device) that are commonly used in IC fabrication to test the functionality of integrated circuits. As such, the RFID integrated circuit 70 may be included in a semiconductor wafer that is undergoing testing, and the test device 68 may comprise a probe-tester. As shown in FIG. 7A, the test device 68 includes a calibration module 72 that is responsible for the inclusion of calibration data within a test signal supplied to the RFID integrated circuit 70 during testing. The calibration module 72 operates to include calibration data (e.g., a calibration command and an update value) within the test signal, the calibration data causing calibration values 76 to be stored the non-volatile memory of the RFID integrated circuit 70. For example, the calibration data may include an update value by which a previously stored calibration value 76 is to be incremented or decremented so as to properly calibrate an oscillator 82 included within the RFID integrated circuit 70. Alternatively, the update valve may itself constitute a calibration value 76 to replace a previously stored calibration value or to be stored as an initial calibration value. The oscillator 82, also described in further detail below, is utilized in the provision of clock signals to various components (e.g., a modulator) within the RFID integrated circuit 70. The frequency of signals generated by the oscillator 82 may be at least partially determined by the calibration values 76. In the exemplary embodiment illustrated in FIG. 7A, the test device 68 is also shown to include a transmit/receive (TX/RX) interface 73 via which the test device 68 communicates test signals to the RFID integrated circuit 70, and via which the RFID integrated circuit 70 communicates test result data back to the test device 68. As noted above, the calibration data provided by the calibration module 72 to the RFID integrated circuit 70 may include a calibration command, and an update value. The update value may comprise a delta value by which a previously stored calibration value is to be incremented or decremented. Alternatively, the update value may itself constitute a calibration value to be stored directly into the non-volatile memory 78. In either embodiment, the calibration module 72, as a component of the test device 68, is responsible for the calculation of one or more update values. To this end, the calibration module 72 is additionally configured to receive test data back from the RFID integrated circuit 70, via the transmit/receive interface 73, and to determine whether the generation and communication of a further update value is required in order to properly calibrate the RFID integrated circuit 70. The test data received by the calibration module 72 may comprise the backscatter-modulated output of a modulator included within the RFID integrated circuit 70. In this case, the calibration module 72 recovers timing information from the received backscatter modulated signal to determine whether the frequency modulation of this signal is correct. If not, the calibration module 72 generates an update value with which to modify or replace a currently stored calibration value 76. Accordingly, in the exemplary embodiment, described with reference to FIG. 7A, the logic for the calculation of appropriate calibration values 76 is shown to reside within the test device 68. FIG. 7B illustrates an alternative embodiment for the test system 66, wherein the calibration module 75, and accordingly the logic for the calculation and generation of update values, resides in the RFID integrated circuit 70 itself, and not within the test device 68. In this exemplary embodiment, one of the test signals propagated by the transmit/receive interface 73 of the test device 68 may be a frequency signal, which is received by the calibration module 75, and utilized to recover timing or clock information. The calibration module 75 is also shown to receive, as input, the output of an oscillator 82 of the RFID integrated circuit 70. By comparison of the output of the oscillator 82 and the recovered timing information, the calibration module 75 may calculate an appropriate calibration value 76 according to which the oscillator 82 should be calibrated. Having calculated an appropriate calibration value 76, the calibration module 75 proceeds to write this calibration value 76 into the non-volatile memory 78. The system 67 shown in FIG. 8A includes an RFID reader 84 that includes a calibration module 86 to include calibration data in radio-frequency signals communicate to an RFID integrated circuit 70 to facilitate the generation and/or storage of the calibration values 76 in the non-volatile memory 78 of an RFID integrated circuit 70. The system 67 shown in FIG. 8A includes a calibration module 86, for example similar to the calibration module 72 described above, within the RFID reader 84. Accordingly, in this embodiment, the calibration logic resides largely with the RFID reader 84. FIG. 8B, on the other hand, shows an alternative embodiment of the system 67, wherein a calibration module 87 resides within the RFID integrated circuit 70. As with the embodiments described above with reference to FIGS. 7A and 7B, the embodiments illustrated in FIGS. 8A and 8B differ. The RFID reader 84, in the embodiment illustrated in FIG. 8A, receives a backscatter modulated signal from the RFID integrated circuit 70, in response to a programming signal, with update values being generated at the RFID reader 84 and then communicated back to the RFID integrated circuit 70. In the embodiment illustrated in FIG. 8B, on the other hand, the calibration module 87 may, as described above, recover timing information from the programming signal, and generate and store the calibration value 76 based on the recovered timing information. From FIGS. 7A, 7B, 8A and 8B, it will be appreciated that calibration data, according to various embodiments of the present invention, may be provided to an RFID integrated circuit 70 by a test device 68 or an RFID reader 84. Furthermore, the communication of the calibration data is not limited to communication via a radio-frequency link. In other embodiments of the present invention, the calibration data may be provided to the RFID integrated circuit 70 to via a wire link (e.g., via probes of a test device 68). The systems 66 and 67 are also merely exemplary systems by which calibration data may be imparted to, and/or stored within, an RFID integrated circuit 70. FIG. 9 is a block diagram illustrating an RFID tag 100, according to an exemplary embodiment of the present invention, that includes one or more antennae 102 coupled to an RFID integrated circuit 106, the antennae 102 and integrated circuit 106 being coupled via one or more pads 104, and accommodated on a common substrate or base material. Turning specifically to the RFID integrated circuit 106, a front-end of the circuit 106 includes a rectifier 108 that operates to extract power from a forward link radio-frequency signal, received via the antenna 102 and communicated to the rectifier 108 via one or more pads 104. The rectifier 108 is coupled to provide extracted power to a power regulator 114, which in turn provides a regulated voltage (VDD) to various components of the integrated circuit 106. The front-end also includes a demodulator 110 that demodulates received radio-frequency signals, and extracts received (RX) data there from, which is then communicated to a tag controller 118. The received data includes, for example, commands, and associated command data, that are issued from an RFID reader (not shown) to interrogate the RFID tag 100. The commands included within the received data may be commands conforming to an RFID communications protocol (e.g., EPC Radio-Frequency Identification Protocol, as specified by the EPC Global Hardware Action Group). The front-end further includes a modulator 112 that operates to modulate transmission (TX) data that is supplied to the modulator 112 from the tag controller 118. The transmission data may include, for example, data that is retrieved from a tag memory 120 by the tag controller 118, and is provided in a reply responsive to commands included within the received data. This data may include a programmed identification code (e.g., an EPC). The modulator 112 operates to backscatter modulate the transmission data, and to provide a backscatter modulated transmission signal to the antenna 102, which then transmits a backscatter radio-frequency signal. A back-end of the RFID integrated circuit 106 includes the tag controller 118 and associated tag memory 120. In one exemplary embodiment, the tag controller 118 may conceptually be regarded as a “core” of the RFID circuit 106. The tag controller 118 includes a command decoder 122 to decode commands received within the received data, and to control a state occupied by a tag stage machine 124, responsive to the commands. Specifically, the tag controller 118 may output specific information, and perform certain actions, depending upon the state occupied by the tag state machine 124. As such, the transmission data outputted by the tag state machine may constitute a reply to a specific command included within the received data. The various components of the RFID integrated circuit 106 require respective clock signals to synchronize operations, and also properly to process information received at and transmitted from the RFID integrated circuit 106 (e.g., the demodulator 110 and the modulator 112 each require respective clock signals to enable proper demodulation and modulation.). To this end, the RFID integrated circuit 106 includes clock generation circuitry 127. In exemplary embodiment, the clock generation circuitry 127 includes a digitally-controlled oscillator (DCO) 128 that is shown to receive, as a control input, a calibration value 126 stored within the non-volatile tag memory 120. The calibration value 126 causes of the frequency of the oscillator 128 to be calibrated to a desired frequency (e.g., a backscatter modulation frequency). In certain embodiments, a register (not shown) may be interposed between the non-volatile tag memory 120 and the digitally-controlled oscillator 128. The oscillator 128 in turn outputs a frequency signal 130 (e.g., a square wave signal), the frequency signal 130 providing input to a counter module 132. The counter module 132 may include one or more counters that utilize the frequency signal 130 to generate one or more clock signals. For example, the counter module 132 may utilize the frequency signal 130 to generate a modulator clock signal 136 that is provided to the modulator 112, so as to enable the modulator 112 to backscatter modulate the transmission data. The counter module 132 is also shown to provide various clock signals to other components of the RFID integrated circuit 106. It will be appreciated that these various clock signals may in fact be the same clock signal, or may be different clock signals, depending upon the requirements of the various components. Further, the counter module 132 may, in one embodiment, form part of the tag controller 118. It will also be noted that the tag state machine 124 provides a command signal to the counter module 132, in the exemplary form of a multiplication signal 134, which controls the manner in which the counter module 132 generates respective clock signals. For example, a counter within the counter module 132 that is utilized to generate the modulator clock signal 136 may be controlled by the multiplication signal 134 to control the frequency of the modulator clock signal 136. In this embodiment, the frequency with which the modulator 112 modulates a backscatter radio-frequency signal is thus controlled at least partially by the multiplication signal 134. As such, the modulation of the backscatter radio-frequency signal may be performed in accordance with both the oscillation frequency signal 130, that is determined by the calibration value 126, as well as the command signal, in the exemplary form of the multiplication signal 134, that provide input to the counter module 132. Of course, clock signals other than the modulator clock signal 136 may similarly be generated utilizing the frequency signal 130 and the multiplication signal 134. The exemplary RFID integrated circuit 106 illustrated in FIG. 9 presents a number of advantages. As the oscillation of the oscillator 128 is calibrated utilizing the calibration value 126, which is pre-stored within the non-volatile memory 120 and is not recovered from a radio-frequency signal received on the radio-frequency forward link, operational speed of the RFID integrated circuit 106 may be improved. For example because the oscillator 128 does not require calibration relative to a recovered clock signal on every power-on, performance advantages may be achieved. Further, by allowing the modulation of various clock signals within the RFID integrated circuit 106 to be modified responsive to commands received at the tag 100, an RFID reader is provided with control over backscatter radio-frequency signals that are issued in response to interrogation signals. FIG. 10 is a diagrammatic representation of an RFID tag 140, according to a further exemplary embodiment of the present invention, which again includes one or more antennae 102 and an RFID integrated circuit 141. The integrated circuit 141 differs from the exemplary embodiment in FIG. 9 in that a dual-oscillator architecture is provided. Specifically, the integrated circuit 141 includes (1) a modulator/core oscillator 142 that is utilized to generate a modulator clock signal 144 and a core clock signal 148, and (2) a demodulator oscillator 146 that is utilized to generate a demodulator clock 149. The oscillators 142 and 146 are distinguished in that the modulator/core oscillator 142 may be calibrated utilizing one or more calibration value 126 stored within the non-volatile tag memory 120, whereas the demodulator oscillator 146 is driven by timing recovered from a received radio-frequency signal. The dual-oscillator architecture provides the advantage that the need for over-sampling of a received radio-frequency signal may be reduced relative to the over-sampling requirements of the architecture described above with reference to FIG. 9. Nonetheless, the advantages provided by calibrating the modulator/core oscillator 142, utilizing a calibration value 126 stored within a non-volatile memory, as described above with reference to FIG. 9, remain. FIG. 11 is a diagrammatic representative of yet a further exemplary embodiment of an RFID tag 150. Again, the RFID tag 150 is comprised of an antenna 102 coupled to an RFID integrated circuit 152. The RFID integrated circuit 152 is shown to include a non-volatile tag memory 154 in which are stored multiple calibration values 156, 158. Clock generation circuitry 160 includes a selection mechanism, in the exemplary form of a multiplexer (MUX) 162, which is operable by the tag state machine 124 (in turn responsive to a decoded command) to select one of the multiple calibration values 156, 158 stored within the non-volatile tag memory 154. The selected calibration value is then utilized to drive a digitally-controlled oscillator (DCO) 166, which in turn generates a modulator clock signal 144. For the sake of simplicity, the clock generation circuitry 160 is only shown to generate a modulator clock signal 144. It will nonetheless be appreciated that the clock generation circuitry 160 may be utilized to produce clock signals for any of the components of the RFID integrated circuit 152. The architecture illustrated in FIG. 11 is advantageous in that an oscillator can accordingly be driven by any one of multiple calibration values stored within a non-volatile memory 154, the choice of calibration values being controlled by the tag controller 118. As described above, the selection performed by the tag controller 118 may be performed responsive to a command sent, for example, by an RFID reader and included in the received data extracted by the demodulator 110. Consider the situation in which an RFID reader (not shown) requires the RFID tag 150 to backscatter at one of a number of possible backscatter frequencies. In this embodiment, a number of backscatter values, corresponding to a number of possible backscatter frequencies, may be stored in the tag memory 154. A command may be then communicated from the RFID reader to the RFID tag 150, instructing a specific backscatter frequency. Responsive to this command, the tag state machine 124 may be placed in a state in which a calibration value, to calibrate the oscillator 166 to generate an appropriate modulator clock signal 144, may be selected for input, via the MUX 162, to the digitally-controlled oscillator 166. In this manner, the output of the tag state machine 124 can be utilized to control the frequency of a modulator clock signal provided to a modulator 112 of an RFID integrated circuit. However, in the embodiment illustrated in FIG. 11, as opposed to generating a multiplication signal 134, the tag state machine 124 outputs a MUX selection signal 164. In other embodiments of the present invention, the selection of an appropriate calibration value may be performed by the tag controller 118 responsive to other inputs or conditions, such as a mode of operation of the RFID tag 150, a sensed temperature of a component of the RFID tag 150 or of a particular environmental (or ambient) condition, a voltage within the RFID tag 150, etc. Information regarding such other inputs or conditions may be provided to the tag controller 118 via commands received from an RFID reader, or via sensors that are coupled to the RFID tag 150. In further exemplary embodiments, a frequency of an RFID chip may be changed in response to process variations as measured by threshold voltage relative to an on-chip voltage reference, or may be changed in response to a measure of noise an interference seen by the demodulator. The storage of multiple calibration values 156 and 158, and the ability to dynamically select a calibration value to drive an oscillator, is advantageous in that this allows the clock signals within the RFID integrated circuit 152 to be dynamically varied in response to received commands, or monitored internal or external conditions. For example, in order to render the RFID tag 150 operable in a number of different regulatory environments, the frequency may need to be adjusted by 10%, for example, to fit within regulatory constraints. In this case, the reader sends a command to switch to an appropriate frequency, responsive to which the RFID tag 150 would switch to the correct frequency. In another embodiment, a sensor (or other component, e.g., the demodulator) may provide an indication that received power is low and the clock may then be slowed automatically to save power, at the expense of a reduced set of recognized commands. FIG. 12 is a diagrammatic representation of an RFID tag 170, according to one further exemplary embodiment of the present invention. The architecture of the RFID tag 170 illustrated in FIG. 12 differs from that illustrated in FIG. 11 in that the clock generation circuitry 174 of the RFID integrated circuit 172 includes a voltage-controlled oscillator (VCO) 182, as opposed to the digitally-controlled oscillator 166 of the RFID integrated circuit 152. Accordingly, the clock generation circuitry 174 is shown to include a register 178 to store a selected calibration value outputted from the MUX 176, a digital-to-analog converter (DAC) 180 to convert the selected calibration value stored in the register 178 to a voltage signal, the voltage control oscillator 182, and a counter 184. FIG. 13 is a flowchart illustrating a method 200, according to an exemplary embodiment of the present invention, to program calibration of an oscillator within a radio-frequency identification (RFID) integrated circuit for use in a RFID tag. The programming performed in the method 200 is performed by an RFID reader device, which communicates with the RFID tag utilizing a radio-frequency forward link. The method 200 may be performed within the context of a system 67 such as that shown in FIG. 8A. The method 200 commences at block 202 with the RFID reader transmitting a calibration mode command to the RFID tag, in order to place the tag into a programming mode (e.g., the programming mode 64 discussed above with reference to FIG. 6). Responsive to receipt of the programming mode command, at block 204, the RFID integrated circuit enters a programming mode in which the RFID reader is provided with command access to a non-volatile memory that forms part of the RFID integrated circuit, or alternatively is a distinct non-volatile memory to which the RFID integrated circuit has access. At block 206, the RFID reader then proceeds to transmit a calibration command to the RFID tag, the calibration command in one exemplary embodiment instructing the RFID tag to write an update value to a non-volatile tag memory of the RFID tag. In the exemplary embodiment, the calibration command takes the form of a “write” command in the following format: [Preamble: 6-bit], [Command: 8-bit], [Memory Address: 2-bit], [Data: 16-bit], [CRC: 8-bit] The 8-bit command is recognized by a command decoder 122 of a tag controller 118 as specifying a write command, with the data (e.g., the update value) being included within the 12-bit data portion of the write command. Returning to the flowchart illustrated in FIG. 13, at block 208, the RFID integrated circuit, having received a radio-frequency signal from the RFID reader in which the command is modulated, demodulates the received radio-frequency signal utilizing the demodulator 110, and communicates the command data to the command decoder 122 of the tag controller 118. The command decoder 122 then provides the appropriate command information to the tag state machine 124 which then proceeds to write the included update value into the non-volatile memory 120 associated with the RFID integrated circuit. As was noted above, the update value that is communicated as part of the command data at block 206, and that is received by the RFID integrated circuit, may itself constitute a calibration value, which is then written to the non-volatile memory 120. In an alternative embodiment, the update value may be a value by which a previously calculated and stored calibration value 126 is to be modified. In this case, the command associated with the update value may further instruct an increment or a decrement operation with respect to a stored calibration value 126, utilizing the update value. In this embodiment, the operations performed at block 208 accordingly include the performance of an appropriate increment or decrement operation to thereby generate a new calibration value 126 to be written into the non-volatile memory 120. The method 200 then proceeds to decision block 210, where the RFID reader determines whether any further calibration values are to be written into the non-volatile memory of the target RFID tag. For example, as noted above with reference to FIGS. 11 and 12, multiple calibration values 156, 158 may be stored within the non-volatile memory of an RFID tag. In the event that it is determined at decision block 210 that further calibration values are in fact to be programmed, the method 200 loops back to block 206. On the other hand, if no further calibration values are to be programmed, the method 200 proceeds to block 212, and the RFID reader transmits an exit programming mode command to the RFID tag, responsive to which the RFID integrated circuit exits programming mode at block 214. The exit programming mode command may be a “lock” command that operates to prevent subsequent write operations to the non-volatile memory of the RFID tag. The method 200 then terminates at block 216. While the method 200 is described above as having the RFID reader transmit a programming mode command and an exit programming mode command to the RFID integrated circuit to render the RFID integrated circuit programmable and non-programmable with respect to update values, it will be appreciated that, in other embodiments of the present invention, the RFID integrated circuit could automatically enter a programming mode upon receiving a calibration command, such as that discussed with reference to block 206. It is worth noting that the programming of the calibration values into the non-volatile memory of the RFID tag, as discussed above with reference to FIG. 13, is not dependent upon the frequency of the radio-frequency signal transmitted by the RFID reader. In other words, the calibration value that is written into the non-volatile memory is not derived from a frequency of the forward link radio-frequency signal itself, but is rather communicated as, or derived from, a specific value associated with a command communicated from the RFID reader to the RFID tag. FIG. 14 is a flowchart illustrating a method 220, according to a further embodiment of the present invention, to program calibration of an oscillator within a radio-frequency identification (RFID) integrated circuit. The programming performed in the method 220 is performed by a test device 68, for example within the context of a system 66 as described above with reference to FIG. 7B. The method 220 commences at block 222 with the initiating and testing of an RFID integrated circuit. The testing of the RFID integrated circuit may be as part of the testing of an entire wafer on which the RFID integrated circuit is included, a die including the RFID integrated circuit, of the RFID integrated circuit once rendered as a distinct chip, or as part of testing the assembled RFID tag. At block 224, the RFID integrated circuit optionally enters a programming mode. For example, a test device 168 may issue a programming mode command to the RFID integrated circuit 70 to cause the RFID integrated circuit to transition into the programming mode. At block 226, the test device 68 then provides a test signal to the RFID integrated circuit 70. In one embodiment of the present invention, the test signal has predetermined reference frequency that the RFID integrated circuit 70 utilizes to record a calibration value 76 within a non-volatile memory associated therewith. In alternative embodiments, the test signal may include a command, and an associated update value, for a specification of a calibration value 76. Further, in one embodiment, the test signal may be a DC power line test signal that is applied to the RFID integrated circuit. At block 228, the RFID integrated circuit recovers the reference frequency from the provided test signal. Specifically, the calibration module 75 of the RFID integrated circuit 70 may operate, as described above, with reference to FIG. 7B to extract the reference frequency from the received test signal, and to compare the extracted reference frequency to a current frequency of the oscillator 82. Based on this comparison, the calibration module 75 then calculates a calibration value, appropriate to calibrate the oscillator 82 to the extracted reference frequency. At block 230, the RFID integrated circuit then stores the calibration value, corresponding to the reference frequency, within the non-volatile memory. Specifically, the calibration module 75 may proceed to write the calibration value 76 into the non-volatile memory, as illustrated in FIG. 7B. The operations performed at blocks 228-230 may be iteratively performed in order to determined the proper calibration value to be stored at block 230. At decision block 234, a determination may be made whether any further calibration values (e.g., corresponding to alternative backscatter modulation frequencies) need to be programmed. This determination may be made at the test device 68 or may alternatively be made at the calibration module 75, responsive to which the calibration module 75 may provide an appropriate signal back to the test device 68. In the event that further calibration values are to be programmed, the method 220 then loops back to block 226. On the other hand, should no further calibration values need to be programmed, the method 220 proceeds to block 236, where the RFID integrated circuit 70 exits programming mode. The method then terminates at block 238. FIG. 15 is a flowchart illustrating a method 240, according to an exemplary embodiment of the present invention, to calibrate an oscillator within a radio-frequency identification (RFID) circuit that may form part of an RFID tag, and to generate various clock signals within the RFID circuit accordance with an output of the oscillator. The method 240 commences at block 242 with the receipt, at an RFID tag, of a radio-frequency interrogation signal from an RFID reader. The flowchart of FIG. 15 depicts two high-level operations as performed within the RFID integrated circuit of the RFID tag. Specifically, as designated generally at 243, a recovered clock signal may optionally be generated within the RFID tag based on the received radio-frequency interrogation signal. Separately, and possibly concurrently, as designated generally at 251, one or more programmed clock signals may also be generated within the RFID integrated circuit of the RFID tag. While the generation of the recovered clock signal at 243 may be dependent upon the reception of the radio-frequency interrogation signal, the generation of the programmed clock signals at 251 is not necessarily dependent upon reception of an interrogation signal, as will be more fully appreciated from the below reading. Specifically, the calibration of an oscillator within an RFID circuit from a stored value does not presuppose the reception of an interrogation signal. Turning first to the generation of the recovered clock signal, at block 244, timing information is recovered from the received radio-frequency interrogation signal. Referring, for example, to the exemplary RFID tag illustrated in FIG. 10, the received interrogation signal is received at the demodulator 110 of the RFID integrated circuit 141. The demodulator 110 includes clock recovery circuitry (not shown) that then proceeds to recover the relevant timing information from the received interrogation signal. At block 246, the recovered timing information is written from the demodulator 110 to a volatile memory 109, associated with the digitally-controlled demodulator oscillator 146. At block 248, a recovered clock signal is generated utilizing the recovered timing information, as stored in the volatile memory 109. Specifically, in one exemplary embodiment, the timing information stored within volatile memory 109 provides digital input to the digitally-controlled demodulator oscillator 146, which then outputs a recovered clock signal in the exemplary form of the demodulator clock signal 149. At block 250, the recovered clock signal is provided to at least one component of the RFID integrated circuit 141. For example, the demodulator clock signal 149 is provided to the demodulator 110. Turning now to the generation of a programmed clock signal, which may or may not occur in parallel with the generation of the recovered clock signal, at block 252 stored timing information, in the exemplary form of a calibration value 126, is retrieved from a non-volatile memory (e.g., the tag memory 120). The stored timing information may have been written into the non-volatile memory utilizing any one of the methods described above. Where the non-volatile memory stores multiple calibration values, the retrieval of the stored timing information at block 252 may include selection of a selected calibration value according to one or more selection criterion, discussed above with reference to FIG. 11. At block 254, a programmed clock signal is generated utilizing the stored timing information. Again referring to the exemplary embodiment illustrated in FIG. 10, stored timing information in the exemplary form of a calibration value 126 may be provided to a digitally-controlled modulator/core oscillator 142, which in turn outputs a frequency signal to a counter module 132. The counter module 132 then outputs a programmed clock signal in the exemplary signal in the exemplary form of a modulator clock signal 136. In the alternative embodiment of the present invention described with reference to FIG. 12, the generation of the programmed clock signal may be performed utilizing a voltage-controlled oscillator (VCO). At block 256, the programmed clock signal is provided to at least one component of the RFID integrated circuit. Referring again to the exemplary embodiment illustrated in FIG. 10, the counter module 132 may, for example, provide the modulator clock signal 144 to a modulator 112, as well as provide a core clock signal 148 to at least the tag controller 118 of the RFID integrated circuit 141. The method 240 then terminates at block 258. In summary, it will be noted that the exemplary method 240 may optionally include the generation of both a recovered clock signal and a programmed clock signal within a common RFID integrated circuit. To this end, the relevant RFID integrated circuit may employ the dual-oscillator (or multi-oscillator) architecture discussed above with reference to FIG. 10. FIGS. 16-24 are diagrammatic representations of various exemplary embodiments. In FIGS. 16-24, for the purposes of clarity, only selected components and signals have been illustrated. Turning first to FIG. 16, an RFID tag 260 is shown to be interrogated by, and to respond to, an RFID reader 262. The RFID tag 260 receives a forward-link radio-frequency signal, which is communicated to a demodulator 264. The RFID tag 260 further includes a digitally-controlled oscillator (DCO) 266, which is calibrated using a calibration value stored within a non-volatile memory 268, and generates a demodulator clock signal 270. The calibration value stored within the non-volatile memory 268 may be written into the memory 268 utilizing any one of the methods discussed above. Accordingly, a non-volatile memory (NVM) calibrated-oscillator is utilized to generate the demodulator clock signal 270 to clock the demodulator 264 utilizing timing information recovered from the forward-link radio-frequency signal. In one embodiment, in order to ensure a required accuracy in the demodulation of the forward-link radio-frequency signal, the demodulator clock signal 270 may be programmed so that the demodulator 264 oversamples the received forward-link radio-frequency signal. The arrangement illustrated in FIG. 16 is advantageous in that no training sequence is required to calibrate the oscillator 266 based on recovered timing information from the forward-link radio-frequency signal. FIG. 17 is a diagrammatic representation of an RFID tag 271, in which the NVM-calibrated oscillator 266 is utilized to drive a modulator clock signal 272, which is in turn utilized to clock a modulator 274 of the RFID tag 271. Accordingly, it will be appreciated that a frequency of a backscatter-modulated radio-frequency signal 276, transmitted from the RFID tag 271 to the RFID reader 262, is related to the frequency of the modulator clock signal 272. It should furthermore be noted that the modulator clock signal 272 is not necessarily related to the demodulator clock signal 270. For example, the demodulator and modulator clock signals 270 and 272 may be driven by different calibration values stored within the non-volatile memory 268. Further, in a dual-oscillator architecture, separate oscillators may be provided to generate each of the demodulator and modulator clock signals 270 and 272. FIG. 18 is a block diagram illustrating an exemplary RFID tag 280, in which an NVM-calibrated clock signal 282 is provided to a digital core 284 of the RFID tag 280. Again, the system clock signal 282 need not necessarily be related to the demodulator and modulator clock signals 270 and 272 discussed above. For example, independent calibration values may be stored within the non-volatile memory 268 to generate each of the clock signals 270, 272 and 282. Further, independent oscillators 266 may be provided to generate each of these clock signals. Of course, in certain embodiments, each of the clock signals 270, 272, and 282 may, in fact, be driven by a common calibration value, stored within a common non-volatile memory, and provided to a common oscillator 266. FIG. 19 is a diagrammatic representation of an RFID tag 290, according to one exemplary embodiment of the present invention, with an oscillator 266 being driven by any one of a multiple calibration values stored within a non-volatile memory structure. Specifically, the provision of one of the calibration values 292 and 294 to the oscillator 266 is shown to be controlled by an on-chip digital controller, in the exemplary form of the digital core 284. The high-level architecture depiction shown in FIG. 19 could, it will be appreciated, be implemented in the manner discussed above with reference to FIG. 11, wherein calibration values 156 and 158 are stored within a non-volatile memory 154, and wherein the digital core 284 includes the tag controller 118, which in turn includes the tag state machine 124 that outputs a selection signal 164 to select between one of multiple calibration values. As also noted above, the selection of the appropriate calibration value 292 or 294 may be dependent upon any number of factors, including a mode of operation of the digital core 284, commands received at the RFID tag 290 from an RFID reader 262, tag temperature, tag voltage, etc. FIG. 20 is a diagrammatic representation of an RFID tag 300 according to further embodiment of the present invention, wherein an oscillator 266 is driven by a calibration value stored within a non-volatile memory 302, or alternatively by a calibration value stored within a volatile memory (e.g., a register 304). The non-volatile memory 302 may itself store multiple calibration values between which a selection may also be made. The choice between a calibration value stored within the non-volatile memory 302 and the volatile register 304 is, as with the embodiment described below with reference to FIG. 19, controlled by the digital core 284. Specifically, a digital state (e.g., the state of a tag state machine 124) may determine the selection performed by the digital core 284. For example, when the RFID tag 300 is receiving a forward-link radio-frequency signal that requires demodulation, the digital core 284 may place the RFID tag 300 in a demodulation state, and accordingly select a value within the volatile register 304 to drive the oscillator 266, and to output an appropriate demodulation clock to a demodulator (not shown). Alternatively, when the RFID tag 300 is transmitting a backscatter modulated radio-frequency signal as a reply to an RFID reader, the digital core 284 may place the RFID tag 300 in a modulation state, and accordingly select a calibration value within the non-volatile memory 302 to drive the oscillator 266. The oscillator 266 will then accordingly output an appropriate modulation clock signal to a modulator (not shown). It should furthermore be noted that one or more of calibration values stored within the non-volatile memory 302 may be programmatically written and stored within the memory 302, whereas a value stored within the volatile register 304 may represent recovered timing information, recovered from a forward link radio-frequency signal received at the RFID tag 300. FIG. 21 is a diagrammatic representation of an RFID tag 310, according to one embodiment of the present invention, where a single NVM-calibrated oscillator 266 is utilized to drive modulator, demodulator, and system clock signals 314, 318, and 319. This embodiment is in contrast to a further exemplary embodiment of an RFID tag 330, illustrated in FIG. 22, which employs a multi-oscillator architecture. Specifically, in the embodiment illustrated in FIG. 22, a first oscillator 322 is dedicated to the generation of a demodulation clock 336, and is driven by timing information recovered from a forward-link radio-frequency signal, and represented by a calibration value stored within a volatile register 334 that provides input to the oscillator 332. A second oscillator 340 is responsible for the generation of a modulator clock signal 348 and a system clock signal 344. The second oscillator 340 is calibrated utilizing a calibration value stored within a non-volatile memory 342, which provides input to the second oscillator 340. FIGS. 23 and 24 are diagrammatic representations of an RFID tag 360, according to an even further exemplary embodiment of the present invention, with a single oscillator which is selectively calibrated utilizing values stored within a non-volatile memory 366 and values stored within a volatile memory, in an exemplary form of a volatile register 364. The non-volatile memory 366 and the volatile register 364 provide an example of a tag memory structure. As has been discussed in detail above, the selective provision of a calibration value from either the non-volatile memory 366 or the volatile register 364 is controlled by a digital core 372, and may be based on a state occupied by the RFID tag. FIG. 23 illustrates that, during data recovery, the oscillator 362 is driven by a calibration value stored within the volatile register 364, to generate a demodulator clock signal 368. The calibration value stored within the volatile register 364 is furthermore shown to reflect recovered timing information, as generated an outputted by a demodulator 370. Accordingly, during data recovery, the demodulator clock signal 368 may be set according to timing information recovered from a forward link radio-frequency signal received at the RFID tag 360. FIG. 24, on the other hand, illustrates that during modulation, the oscillator 362 may be driven by a calibration value stored within the non-volatile memory 366. As discussed above, the calibration value stored within the non-volatile memory 366 may be programmed (e.g., during a programming event or mode). Accordingly, the oscillator 362 is utilized to drive a programmed clock signal, in the exemplary form of the modulator clock signal 374, that is provided to the modulator 376. Accordingly, the modulator 376 backscatter modulates a transmitted radio-frequency signal in accordance with the received modulator clock signal 374. The calibration modules discussed above may employ any one of a number of calibration algorithms in order to determine one or more calibration values 76 to be stored within the non-volatile memory of an RFID tag. In one exemplary embodiment, a calibration module may employ the so-called Successive Approximation Algorithm (SAA) that assumes, without loss of generality, that higher settings give a higher frequency. Accordingly, the algorithm typically starts with the most-significant bit (MSB), recognizing the MSB as a test bit. The test bit is set to one, and all lower bits are set to zero. The inherent frequency of an oscillator 82 to be calculated is compared to an external reference frequency. As noted above, this reference frequency may be provided via a radio-frequency (or other air or a wired link (e.g., through probing at test time)). If the observed frequency of the oscillator 82 is too high, the test bit is set to zero, and the next most significant bit is selected as the test bit, and set to 1. The above process is repeated until the observed frequency of the oscillator 82 corresponds to the provided external reference frequency. In a further embodiment, a calibration module may employ a feedback algorithm to generate one or more calibration values to be written into the non-volatile memory 78 of an RFID integrated circuit 70. Specifically, such an algorithm sets the calibrated output frequency of an oscillator 82 at a mid-range, and then counts how many external clock cycles (E) pass in a fixed number of internal clock cycles (I). The algorithm adjusts the calibrated outward frequency of the oscillator 82 proportionately to (E-I) until this value is sufficiently small. FIG. 25 is a schematic diagram illustrating a portion of exemplary clock generation circuitry 380 including a core oscillator 382, and calibration module 384. Within the calibration module 384, M1 mirrors a reference current (Iref) to M2-M5. Calibration is applied to the gates of M6-M9 to control the current supplied to the core oscillator 382. It should also be noted that embodiments of the present invention may be implemented and not only as a physical circuit or module (e.g., on a semiconductor chip) but, also within a machine-readable media. For example, the circuits and designs described above may be stored upon, or embedded within, a machine-readable media associated with a design tool used for designing semiconductor devices. Examples include a netlist formatted in the VHSIC Hardware Description Language (VHDL), the Verilog language, or the SPICE language. Some netlist examples include a behavioral level netlist, a register transfer level, (RTL) netlist, a gate level netlist, and a transistor level netlist. Machine-readable media include media having layout information, such as a GDS-II file. Furthermore, netlist files and other machine-readable media for semiconductor chip design may be used in a simulation environment to perform any one or more methods described above. Thus it is also to be understood that embodiments of the present invention may be used, or to support, a software program executing on some processing core (e.g., a CPU of a computer system), or otherwise implemented or realized within a machine-readable medium. A machine-readable medium may include any mechanism for storing and transmitting information in a form readable by a machine (e.g., a computer). For example, a machine readable-readable medium may comprise a read-only memory (ROM), a random access memory (RAM), magnetic disc storage media, optical storage media, flash memory devices, electrical, optical, acoustic, or other form of propagated signal (e.g., a carrier wave, infrared signal, radio-frequency signal, a digital signal, etc.). Thus, a calibrated oscillator for an RFID system, and methods of manufacturing and operating the same, has been described. Although the present invention has been described with reference to specific exemplary embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. | <SOH> BACKGROUND OF THE INVENTION <EOH>Radio-frequency identification tags (or transponders) require a reference frequency for a number of purposes. An RFID reader transmits RF power to RFID tags. RFID tags modulate reflected RF power to transmit data back to an RFID reader. The reflected RF is called ‘backscatter,’ and the link from the tag back to the reader is typically referred to as the ‘backscatter link. The backscatter modulation of course requires a backscatter frequency to which the relevant RFID reader is sensitive. Furthermore, backscatter communications may be subject to regulatory restrictions, and may need to be compliant with one or more RFID communications specifications or standards. An RFID tag also requires a demodulation frequency so as to enable a demodulator within the RFID tag to demodulate received radio-frequency signals, and decode data contained therein. RFID tags also need to generate internal clock signals to clock various functional units that may be included within the RFID tag. With a view to generating the above-identified frequency and clock signals within an RFID tag, the RFID tag is typically equipped with an oscillator that generates the reference frequency. Three prior art mechanisms for providing such a reference frequency are discussed below. FIG. 1 is a schematic illustration of a first prior art oscillator arrangement 10 in which an oscillator 12 is coupled to a crystal 14 in order to provide a precise local reference frequency. Alternatively, the oscillator 12 may be coupled to an L-C tank or electron mobility-based reference in order to provide the precise local reference frequency. A disadvantage of such arrangements is that they tend to be bulky, and high-power consumers. A second manner in which it is known to provide a reference frequency within an RFID chip is to provide a phase-locked loop (PLL) arrangement, such as that illustrated by the schematic diagram of FIG. 2 . Specifically, the phase-locked loop arrangement 16 of FIG. 2 is shown to include a phase detector 18 that is coupled to receive a reference frequency 20 and the oscillator output, compare them, and to provide a reference signal 22 to an oscillator 24 . The disadvantages of the phase-locked loop arrangement 16 shown in FIG. 2 include the required provision of a reference frequency, a long start-up time, the provision of extra power for the phase detector 18 , as well as the extra chip area requirements for provision of the phase detector 18 . A similar function can also be done with a frequency detector, and a frequency-locked loop. A third prior art arrangement 26 to provide a reference frequency within an RFID tag is illustrated by the schematic diagram of FIG. 3 . Specifically, a trimming arrangement 28 comprising a combination of resistors, capacitors and inductors (or fuses or resistors that may be laser-cut) provide a reference signal 22 (e.g., a current reference signal I ref ) to an oscillator 30 . Among the disadvantages of this arrangement are that the trimming arrangement may be expensive to build, and the configuration of the trimming arrangement 28 is permanent (i.e., the oscillator 30 cannot be dynamically calibrated). FIGS. 4 and 5 are diagrammatic representations of a prior art RFID system 32 including an RFID tag 34 that is interrogated by, and responds to, an RFID reader 36 utilizing a radio-frequency forward link and a backscatter return link. The RFID tag 34 is shown to provide a signal received from the RFID reader 36 , via the radio-frequency forward link, to a demodulator 38 , which recovers a timing (or clock) signal 40 . The recovered clock signal 40 is utilized to generate a digital calibration value 44 , which is stored in a volatile register 42 . The volatile register 42 in turn provides the digital calibration value 44 to a digitally-controlled oscillator (DCO) 46 . The digitally-controlled oscillator 46 outputs a demodulator clock signal 48 . FIG. 5 illustrates the oscillator 46 of the RFID tag 32 , again calibrated utilizing a digital calibration value 44 provided to the oscillator 46 from the volatile register 42 . The oscillator 46 generates a modulator clock signal 52 to a modulator 50 , the modulator 50 utilizing the modulator clock signal 52 to backscatter modulate communications transmitted via the backscatter return link to the RFID reader 36 . In summary, it will be appreciated that, on start-up, the RFID reader 36 sends a radio-frequency forward link signal to the RFID tag 34 , which extracts a timing (or clock) signal 40 from the received signal to calibrate the oscillator 46 , this recovered timing signal 40 being communicated to the oscillator 46 via the register 42 . During backscatter communications, the calibration is held by the oscillator 46 , which is in turn utilized to drive the modulator 50 . Accordingly, in the prior art system shown in FIGS. 4 and 5 , the recovered timing signal 40 is stored within a volatile register that is utilized to calibrate the oscillator. However, a clock recovery operation is required by the demodulator 38 upon each power-up event, which may negatively impact the performance of the RFID tag 32 . U.S. Pat. No. 5,583,819, entitled “Apparatus and Method of Use of Radiofrequency Identification Tags”, to Bruce B. Roesner and Ronald M. Ames, discloses an RFID tag in which a reference signal is initially generated by comparing an incoming standard signal, and placing it in a temporary or permanent storage within the RFID tag. Signals arriving later are then compared to the captured standard, and variations from the captured standards are detected to allow for decoding of the data. Specifically, a microprocessor is described as providing a correction signal to a memory, the correction signal then being stored within the memory as a correction value for use in subsequent operation of the RFID tag, or at least until the correction value is updated. The memory is described as possibly being a non-volatile memory to allow calibration information to be permanently stored, so that reconfiguration of the internal oscillator is not required each time the RFID tag is powered up. In the system described by Roesner, the calibration of the oscillator is nonetheless dependent upon an initial extraction or recovery of timing from a received radio-frequency signal. | <SOH> SUMMARY OF THE INVENTION <EOH>According to one aspect of the present invention, there is provided a method to backscatter modulate a first radio-frequency (RF) signal from a radio-frequency identification (RFID) tag. An oscillator calibration value is retrieved from a non-volatile memory associated with the RFID tag. An oscillation frequency signal is generated within the RFID tag, the generating of the oscillation signal being performed utilizing the oscillator calibration value. A command signal is generated within the RFID tag, the command signal being based on command data received at the RFID tag in a second radio-frequency signal from an RFID reader. The first radio-frequency signal is backscatter modulated in accordance with both the oscillation frequency signal and the command signal. Other features of the present invention will be apparent from the accompanying drawings and from the detailed description that follows. | 20040413 | 20080617 | 20051013 | 57748.0 | 2 | AU, SCOTT D | METHOD AND SYSTEM TO BACKSCATTER MODULATE A RADIO-FREQUENCY SIGNAL FROM AN RFID TAG IN ACCORDANCE WITH BOTH AN OSCILLATION FREQUENCY SIGNAL AND A COMMAND SIGNAL | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,824,224 | ACCEPTED | Fluid delivery valve system and method | A method of forming a valve assembly for delivering a fluid from a fluid bag to an animal caging system for housing an animal can include forming, in an injection molding machine, an upper member having a piercing member and a connecting member. The upper member has a fluid channel defined therethrough; and forms, in an injection molding machine, a base having a flange member and a base fluid channel defined therethrough. The base is designed to be matingly coupled to the upper member. The method can further include forming, in an injection molding machine, a stem member designed and dimensioned to be disposed in part within the base fluid channel. The stem member has an actuation portion extending through a spring element. The stem member has a top portion having a lower surface. | 1. A method of forming a valve assembly for delivering a fluid from a fluid bag to an animal caging system for housing an animal, the method comprising: forming, in an injection molding machine, an upper member having a piercing member, said upper member having a fluid channel defined therethrough; and forming, in an injection molding machine, a base having a base fluid channel defined therethrough, wherein said base is designed to be matingly coupled to said upper member. 2. The method of claim 1, further comprising: forming, in an injection molding machine, a stem member designed and dimensioned to be disposed in part within said base fluid channel, said stem member having an actuation portion and a top portion having a lower surface. 3. The method of claim 2, further comprising: forming, in an injection molding machine, a sealing member disposed in said base fluid channel, said sealing member having a flow aperture and a sealing member bottom surface, said sealing member being designed and dimensioned to facilitate sealing of said flow apertures when said sealing member bottom surface abuts a top surface of said stem member. 4. The method of claim 3, said forming said upper member and forming said sealing member comprising: forming said upper member in a first step of a multi-step injection molding process; and forming said sealing member is a second step of said multi-step injection molding process. 5. The method of claim 4, wherein said upper member becomes attached to said sealing member such that said upper member and said sealing member form a single integral piece. 6. The method of claim 1, wherein said upper member is formed of polypropylene. 7. The method of claim 3, wherein said sealing member is formed of silicone rubber. 8. The method of claim 1, further comprising: inserting a portion of said upper member into said base, thereby causing said upper member to be friction fit to said base. 9. The method of claim 8, further comprising: disposing a part of said stem member within said base fluid channel. 10. The method of claim 3, further comprising: disposing a spring element within said base fluid channel; wherein a portion of said spring element abuts said lower surface to apply a biasing force to said stem member. 11. The method of claim 10, wherein said spring element comprises at least one group of dead coils, thereby facilitating prevention of tangling of a plurality of spring members when said spring members are arranged during assembly. 12. The method of claim 10, wherein said spring element comprises three groups of dead coils, one of said groups being located at the center of said spring element, one of said groups being located at a first end of said spring element, and one of said groups being located at a second end of said spring element, thereby facilitating prevention of tangling of a plurality of spring members when said spring members are arranged during assembly. 13. The method of claim 3, wherein said sealing member bottom surface has a lower ridge extending therefrom, said lower ridge being designed and dimensioned to facilitate the concentration of said biasing force from said spring member to seal said flow aperture. 14. The method of claim 3, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed. 15. The method of claim 3, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed with a force of less than or equal to 5 grams. 16. The method of claim 3, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed with a force of less than or equal to 3 grams. 17. The method of claim 1, wherein said valve assembly is disposable. 18. The method of claim 1, further comprising: piercing a fluid bag with said piercing member to facilitate the providing of fluid from the fluid bag to an animal. 19. The method of claim 18, further comprising: disposing of the valve assembly after the animal has consumed fluid from said fluid bag. 20. The method of claim 2, further comprising: disposing a spring element within said base fluid channel; wherein a portion of said spring element abuts said lower surface to apply a biasing force to said stem member. 21. The method of claim 20, wherein said spring element comprises at least one group of dead coils, thereby facilitating prevention of a tangling of a plurality of spring members when said spring members are arranged during the assembly process. 22. The method of claim 20, wherein said spring element comprises three groups of dead coils, one of said groups being located at the center of said spring element, one of said groups being located at a first end of said spring element, and one of said groups being located at a second end of said spring element, thereby facilitating prevention of tangling of a plurality of spring members when said spring members are arranged during assembly. 23. A valve assembly for delivering a fluid from a fluid bag to an animal caging system for housing an animal, the valve assembly comprising: an upper member having a piercing member and a connecting member, said upper member having a fluid channel defined therethrough; a base having a base fluid channel defined therethrough, wherein said base is designed to be matingly coupled to said upper member; a stem member designed and dimensioned to be disposed in part within said base fluid channel, said stem member having an actuation portion and having a top portion having a lower surface; and a sealing member integrally formed with said upper member and disposed in said base fluid channel, said sealing member having a flow aperture and a sealing member bottom surface, said sealing member being designed and dimensioned to facilitate sealing of said flow apertures when said sealing member bottom surface abuts a top surface of said stem member. 24. The valve assembly of claim 23, further comprising: a spring element disposed within said base fluid channel; wherein a portion of said spring element abuts said lower surface to apply a biasing force to said stem member. 25. The valve assembly of claim 24, wherein said spring element comprises at least one group of dead coils, thereby facilitating prevention of a tangling of a plurality of spring members when said spring members are arranged during the assembly process. 26. The valve assembly of claim 24, wherein said spring element comprises three groups of dead coils, one of said groups being located at the center of said spring element, one of said groups being located at a first end of said spring element, and one of said groups being located at a second end of said spring element. 27. The valve assembly of claim 24, wherein said sealing member bottom surface comprises a lower ridge extending therefrom, said lower ridge being designed and dimensioned to facilitate the concentration of said biasing force from said spring member to seal said flow aperture. 28. The valve assembly of claim 23, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed. 29. The valve assembly of claim 23, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed with a force of less than or equal to 5 grams. 30. The valve assembly of claim 23, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed with a force of less than or equal to 3 grams. 31. The valve assembly of claim 24, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed with a force of about 5 grams. 32. The valve assembly of claim 24, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed with a force of about 3 grams. 33. The valve assembly of claim 23, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed with a force of about 3 grams. 34. The valve assembly of claim 24, wherein said stem member has a length of about 0.42 inches. 35. The valve assembly of claim 34, wherein said base fluid channel has a width of about 0.205 inches. 36. The valve assembly of claim 34, wherein said top surface of said stem member has a width of about 0.200 inches. 36. The valve assembly of claim 34, wherein said spring member has an outer diameter of about 0.188 inches. 37. The valve assembly of claim 34, wherein said spring member has a load force when compressed to a length of 0.255 inches in the range of about 18.8 to 25.8 grams. 38. The valve assembly of claim 23, wherein said upper member is formed of polypropylene. 39. The valve assembly of claim 23, wherein said sealing member is formed of silicone rubber. 40. The valve assembly of claim 23, wherein said upper member is friction fit to said base. 41. The valve assembly of claim 23, wherein a part of said stem member is disposed within said base fluid channel. 42. The valve assembly of claim 23, wherein said valve assembly is disposable. 43. A valve assembly comprising: an upper member having a piercing member and a connecting member, said upper member having a fluid channel defined therethrough; a base having a base fluid channel defined therethrough, wherein said base is designed to be matingly coupled to said upper member; a stem member designed and dimensioned to be disposed in part within said base fluid channel, said stem member having an actuation portion and having a top portion having a lower surface; a sealing member integrally formed with said upper member and disposed in said base fluid channel, said sealing member having a flow aperture and a sealing member bottom surface, said sealing member being designed and dimensioned to facilitate sealing of said flow apertures when said sealing member bottom surface abuts a top surface of said stem member; and a spring element disposed within said base fluid channel; wherein a portion of said spring element abuts said lower surface to apply a biasing force to said stem member. 44. A valve assembly for delivering a fluid from a fluid bag to an animal caging system for housing an animal, the valve assembly comprising: an upper member having a piercing member and a connecting member, said upper member having a fluid channel defined therethrough; a base having a base fluid channel defined therethrough, wherein said base is designed to be matingly coupled to said upper member; a stem member designed and dimensioned to be disposed in part within said base fluid channel, said stem member having an actuation portion and having a top portion having a lower surface; and a spring element disposed within said base fluid channel; wherein a portion of said spring element abuts said lower surface to apply a biasing force to said stem member, and said spring element comprises at least one group of dead coils, thereby facilitating prevention of a tangling of a plurality of spring members when said spring members are arranged during the assembly process. 45. The valve assembly of claim 44, wherein said spring element comprises three groups of dead coils, one of said groups being located at the center of said spring element, one of said groups being located at a first end of said spring element, and one of said groups being located at a second end of said spring element. 46. A valve assembly of claim 45, further comprising: a sealing member integrally formed with said upper member and disposed in said base fluid channel, said sealing member having a flow aperture and a sealing member bottom surface, said sealing member being designed and dimensioned to facilitate sealing of said flow apertures when said sealing member bottom surface abuts a top surface of said stem member. 47. The valve assembly of claim 46, wherein said sealing member bottom surface comprises a lower ridge extending therefrom, said lower ridge being designed and dimensioned to facilitate the concentration of said biasing force from said spring member to seal said flow aperture. 48. The valve assembly of claim 44, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed. 49. The valve assembly of claim 44, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed with a force of less than or equal to 5 grams. 50. The valve assembly of claim 44, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed with a force of less than or equal to 3 grams. 51. A method of assembling a valve assembly for delivering a fluid from a fluid bag to an animal caging system for housing an animal, the method comprising: coupling an upper member having a piercing member to a base having a base fluid channel defined therethrough; disposing a stem member in part within said base fluid channel, said stem member having an actuation portion and a top portion having a lower surface; disposing a sealing member in said base fluid channel, said sealing member having a flow aperture and a sealing member bottom surface, said sealing member being designed and dimensioned to facilitate sealing of said flow apertures when said sealing member bottom surface abuts a top surface of said stem member. disposing a spring element within said base fluid channel, wherein a portion of said spring element abuts said lower surface to apply a biasing force to said stem member, and wherein said spring element comprises at least one group of dead coils, thereby facilitating prevention of a tangling of a plurality of spring members when said spring members are arranged during the assembly process. 52. The method of claim 51, wherein said spring element comprises three groups of dead coils, one of said groups being located at the center of said spring element, one of said groups being located at a first end of said spring element, and one of said groups being located at a second end of said spring element. 53. The method of claim 51 wherein said sealing member bottom surface has a lower ridge extending therefrom, said lower ridge being designed and dimensioned to facilitate the concentration of said biasing force from said spring member to seal said flow aperture. 54. The method of claim 51, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed. 55. The method of claim 51, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed with a force of less than or equal to 5 grams. 56. The method of claim 51, wherein said stem member is designed and dimensioned to selectively facilitate the flow of the fluid when said actuation portion is pushed with a force of less than or equal to 3 grams. | CROSS-REFERENCE TO RELATED APPLICATIONS This application is a Continuation-In-Part of U.S. patent application Ser. No. 10/274,619, filed on Oct. 21, 2002, and entitled Fluid Deliver System, currently pending, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/346,218, filed on Oct. 19, 2001, the contents of both applications being hereby incorporated by reference herein. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to fluid delivery systems and in particular to a fluid delivery system and method for caging or storage systems for animals. 2. Description of Related Art A large number of laboratory animals are used every year in experimental research. These animals range in size from mice to non-human primates. To conduct valid and reliable experiments, researchers must be assured that their animals are protected from pathogens and microbial contaminants that will affect test results and conclusions. Proper housing and management of animal facilities are essential to animal well-being, to the quality of research data and teaching or testing programs in which animals are used, and to the health and safety of personnel. Ordinarily, animals should have access to potable, uncontaminated drinking water or other needed nutrient containing fluids according to their particular requirements. Water quality and the definition of potable water can vary with locality. Periodic monitoring for pH, hardness, and microbial or chemical contamination might be necessary to ensure that water quality is acceptable, particularly for use in studies in which normal components of water in a given locality can influence the results obtained. Water can be treated or purified to minimize or eliminate contamination when protocols require highly purified water. The selection of water treatments should be carefully considered because many forms of water treatment have the potential to cause physiologic alterations, changes in microflora, or effects on experimental results. For example, chlorination of the water supply can be useful for some species but toxic to others. Because the conditions of housing and husbandry affect animal and occupational health and safety as well as data variability, and effect an animal's well-being, the present invention relates to providing a non-contaminated, replaceable, disposable source of fluid for laboratory animals in a cage level barrier-type cage or integrated cage and rack system to permit optimum environmental conditions and animal comfort. Animal suppliers around the world have experienced an unprecedented demand for defined pathogen-free animals, and are now committed to the production and accessibility of such animals to researchers. Likewise, laboratory animal cage manufacturers have developed many caging systems that provide techniques and equipment to insure a pathogen free environment. For example, ventilated cage and rack systems are well known in the art. One such ventilated cage and rack system is disclosed in U.S. Pat. No. 4,989,545, the contents of which are incorporated herein by reference, assigned to Lab Products, Inc., in which an open rack system including a plurality of shelves, each formed as an air plenum, is provided. A ventilation system is connected to the rack system for ventilating each cage in the rack, and the animals therein, thereby eliminating the need for a cage that may be easily contaminated with pathogens, allergens, unwanted pheromones, or other hazardous fumes. It is known to house rats, for example, for study in such a ventilated cage and rack system. The increasing need for improvement and technological advancement for efficiently, safely housing and maintaining laboratory animals arises mainly from contemporary interests in creating a pathogen-free laboratory animal environment and through the use of immuno-compromised, immuno-deficient, transgenic and induced mutant (“knockout”) animals. Transgenic technologies, which are rapidly expanding, provide most of the animal populations for modeling molecular biology applications. Transgenic animals account for the continuous success of modeling mice and rats for human diseases, models of disease treatment and prevention and by advances in knowledge concerning developmental genetics. Also, the development of new immuno-deficient models has seen tremendous advances in recent years due to the creation of gene-targeted models using knockout technology. Thus, the desire for an uncontaminated cage environment and the increasing use of immuno-compromised animals (i.e., SCID mice) has greatly increased the need for pathogen free sources of food and water. One of the chief means through which pathogens can be introduced into an otherwise isolated animal caging environment is through the contaminated food or water sources provided to the animal(s). Accordingly, the need exists to improve and better maintain the health of research animals through improving both specialized caging equipment and the water delivery apparatus for a given cage. Related caging system technologies for water or fluid delivery have certain deficiencies such as risks of contamination, bio-containment requirements, DNA hazardous issues, gene transfer technologies disease induction, allergen exposure in the workplace and animal welfare issues. Presently, laboratories or other facilities provide fluid to their animals in bottles or other containers that must be removed from the cage, disassembled, cleaned, sterilized, reassembled, and placed back in the cage. Additionally, a large quantity of fluid bottles or containers must be stored by the labs based on the possible future needs of the lab, and/or differing requirements based on the types of animals studied. This massive storage, cleaning and sterilization effort, typically performed on a weekly basis, requires large amounts of time, space and human resources to perform these repetitive, and often tedious tasks. As such, a need exists for an improved system for delivering fluid to laboratory animals living in cage level barrier-type rack and cage systems. SUMMARY OF THE INVENTION The present invention satisfies this need Briefly stated, in accordance with an embodiment of the invention, a fluid delivery system for delivering a fluid to an animal caging system for housing an animal is described. The fluid delivery system may comprise a fluid delivery valve assembly adapted to be coupled to a fluid bag holding a fluid. By advantageously using sanitized fluid bags, that may be disposable, the invention may minimize the need for the use of fluid bottles that typically must be removed from cages, cleaned, and sanitized on a frequent basis. The delivery system may be utilized in a single cage or in multiples cages integrated into ventilated cage and rack systems known in the art. An embodiment of the invention described herein provides for a fluid delivery system for delivering a fluid from a fluid bag to an animal caging system for housing an animal and may comprise a fluid delivery valve assembly, wherein the fluid delivery valve assembly is adapted to be coupled to the fluid bag to facilitate the providing of the fluid to an animal in the caging system. The fluid delivery valve assembly may further comprise an upper member having a piercing member and a connecting member, the upper member having a fluid channel defined therethrough, a base having a flange member and a base fluid channel defined therethrough, wherein the base is designed to be matingly coupled to the upper member. The fluid delivery valve assembly may further comprise a spring element disposed within the base fluid channel and a stem member disposed in part within the base fluid channel, wherein a portion of the spring element abuts the stem member to apply a biasing force. Another embodiment is directed to a method of forming a valve assembly for delivering a fluid from a fluid bag to an animal caging system for housing an animal can include forming, in an injection molding machine, an upper member having a piercing member and a connecting member. The upper member has a fluid channel defined therethrough; and forms, in an injection molding machine, a base having a flange member and a base fluid channel defined therethrough. The base is designed to be matingly coupled to the upper member. The method can further include forming, in an injection molding machine, a stem member designed and dimensioned to be disposed in part within the base fluid channel. The stem member has an actuation portion extending through a spring element. The stem member has a top portion having a lower surface. Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification. Other features and advantages of this invention will become apparent in the following detailed description of exemplary embodiments of this invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS In the drawing figures, which are merely illustrative, and wherein like reference characters denote similar elements throughout the several views: FIG. 1 is an exploded perspective view of a fluid delivery system incorporated into an animal cage assembly; FIG. 2 is an exploded perspective view of a fluid delivery system and diet delivery system in accordance with the present invention; FIG. 3 is an exploded perspective view of an embodiment of a fluid delivery valve assembly in accordance with the present invention; FIG. 4 is a side view of the fluid delivery valve assembly of FIG. 3; FIG. 5 is a side cutaway view of the upper member of the fluid delivery valve assembly of FIG. 3; FIG. 6 is a perspective view of trigger assembly of a fluid delivery valve assembly in accordance with the present invention; FIG. 7 is a top plain view of cup element in accordance with the present invention; FIG. 8 is a perspective view of the cup element in accordance with the present invention; FIG. 9 is a cutaway view of cup element in accordance with the present invention; FIG. 10 is a perspective view of a diet delivery system; FIG. 11 is a top plan view of diet delivery system incorporating a fluid delivery system in accordance with the present invention; FIG. 12 is a front cutaway view of diet delivery system; FIG. 13 is a bottom view of a fluid bag in accordance with the present invention; FIG. 14 is a perspective view of a fluid bag and a fluid diet component with a fluid delivery system in accordance with the present invention; FIG. 15 is a cutaway view of a fluid bag in accordance with the present invention; FIG. 16 is a side perspective view of an upper member of a fluid delivery valve assembly including a support in accordance with the present invention; FIG. 17 is a plain side view of a double-sided rack system incorporating an animal cage; FIG. 18 is an exploded perspective view of an embodiment of a fluid delivery valve assembly in accordance with the present invention; FIG. 19 is a side cutaway view of the fluid delivery valve assembly of FIG. 18; FIG. 20 is a perspective view of the stem of the fluid delivery valve assembly of FIG. 18; FIG. 21 is a side cutaway view of the fluid delivery valve assembly of FIG. 18, showing the stem in the sealed position; FIG. 22 is a side cutaway view of the fluid delivery valve assembly of FIG. 18, showing the stem in the opened position; FIG. 23 is a side cutaway view of the fluid delivery valve assembly of FIG. 18, showing the extension portion protecting the stem; FIG. 24 is a side cutaway view of an upper member of a fluid delivery valve assembly including a wrapper in accordance with the present invention; FIG. 25 is a side cutaway view of an upper member of a fluid delivery valve assembly including a disposable cap in accordance with the present invention; FIG. 26 is a fluid bag filling and sealing device in accordance with the present invention; FIG. 27 is a view of a fluid bag preparation room in accordance with the present invention; FIG. 28 is another view of a fluid bag preparation room in accordance with the present invention; FIG. 29 is another view of a fluid bag preparation room in accordance with the present invention; FIG. 30 is a side cutaway view of an exemplary embodiment of a fluid delivery valve assembly; FIG. 31 is a side cutaway view of an exemplary embodiment of a stem of a fluid delivery valve assembly; FIG. 32 is an exemplary representational side view of a spring member for a fluid delivery valve assembly; FIG. 33 is an exemplary schematic diagram of an injection molding machine for forming portions of a fluid delivery valve assembly; FIG. 34 is a plan view of an exemplary mold for injection molding components of a fluid delivery valve assembly; FIG. 35 is a cross-sectional elevational view of the mold of FIG. 34; and FIG. 36 is an exemplary flow diagram illustrating portions of a process for multi-step injection molding parts of a fluid delivery valve assembly. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Reference is made to FIGS. 1 and 2, wherein an animal cage assembly 90, which incorporates fluid delivery valve assembly 1, is shown. Cage assembly 90 incorporates a filter retainer 91, a filter frame 92, a filter top lock 93, a chew shield 94, a plurality of snap rivets 95, a fluid bag 60 containing fluid 70, a fluid delivery valve assembly 1, a diet delivery system 96 providing support member 50, a chow receptacle 111, a fluid bag receptacle 110, and a cage body 98. Cage body 98 comprises a box-like animal cage with a combination diet delivery system 96 capable of providing both food and fluid to animals within cage assembly 90. A filter 99 is also generally provided with cage assembly 90 sandwiched between filter retainer 91 and filter frame 92. Cage body 98 is formed with integral side walls 100, a bottom wall or floor 101 and an open top end. The open top of cage body 98 is bordered by peripheral lip 102, which extends continuously there around. Cage body 98 may also include a plurality of comer stacking tabs 103 for facilitating stacking and nesting of a plurality of cage bodies 98. Reference is made to FIGS. 3-5 wherein fluid delivery valve assembly 1 is depicted. Fluid delivery valve assembly 1 includes an upper member 10, a spring element 20, a trigger assembly 30, and a cup element 40 for use in animal cage 90. Water delivery system 1 is held in place in animal cage 90 by support element 50. Support element 50 extends from diet delivery system 96 and forms a floor for fluid bag receptacle 110. Alternatively, water delivery system 1 may be molded into diet delivery system 96. As shown in FIGS. 4 and 5, upper member 10 includes piercing member 11, core member 12 and flange member 13. Upper member 10 also defines fluid channel 14. Arrow “A” defines the flow of fluid through fluid delivery valve assembly 1 to trigger assembly 30 where fluid flow can be actuated by an animal in animal cage 90. Piercing member 11 has a beveled tip 15 at its upper end, the upper edge of which presents a sharp piercing edge 16 that can come in contact and pierce fluid bag 60, releasing fluid 70 in fluid bag 60 through fluid channel 14. Flange member 13 extends from core member 12. In a preferred embodiment, flange member 13 is circular in dimension. However, it will be readily understood by one of ordinary skill in the art that flange member 13 may be any shape desired, provided however, that at least a portion of flange member 13 is wider in diameter than fluid channel 14 of core member 12. As shown in FIG. 3, spring element 20 may be a tightly wound coiled member which rests atop tip 35 of upper end 33 of stem 31 and enters upper member 10 through fluid channel 14. As shown in FIG. 5, fluid channel 14 is dimensioned such that its upper extent within piercing member 11 is narrowed at position 17 such that it prevents spring element 20 from exiting fluid channel 14 through piercing member 11. Reference is made to FIG. 6, wherein trigger assembly 30 is depicted. Trigger assembly 30 includes a stem 31, inserted through sealing member 32. Stem 31 having an upper end 33 and a lower end 36. Lower end 36 of stem 31 is substantially flat. Upper end 33 of stem 31 is generally conical in shape, although other shapes may be used. Sealing member 32 fits tightly around stem 31 thereby allowing limited movement around stem 31. Sealing member 32 is dimensioned such that the base of the conical portion of upper end 33 rests on it. Sealing member 32 is formed of a resilient material, such as rubber, silicone rubber, or any other pliant malleable material. In a preferred embodiment, sealing member 32 is made of a material that is not deleterious to mammals. Cup element 40 is depicted in FIGS. 7-9. Cup element 40 has a base 43, an inner surface 41, and an outer surface 42. Base 43 also defines actuation channel 400. Lower end 36 of stem 31 of trigger assembly 30 extends through actuation channel 400 towards the interior of animal cage 90. Fluid channel 14 extends from piercing edge 16 through piercing member 11, core member 12 and spring element 20. Fluid channel 14 terminates at the bottom wall of cup element 40. Trigger assembly 30 extends through actuation channel 400. Cup element 40 has friction fit with core member 12 of upper member 10 directly below flange member 13. Diet delivery system 96, which houses fluid bag receptacle 110 and chow receptacle 111 is shown in FIGS. 10-12. As shown in FIG. 11, fluid bag receptacle 110 holds fluid bag 60 containing fluid 70. Fluid delivery valve assembly 1 is held securely in receptacle base 112 of fluid bag receptacle 110 by the interconnection between flange members 13a, 13b, 13c and 13d and locking members 51a, 51b, 51c and 51d. Piercing edge 16 of fluid delivery valve assembly 1 punctures fluid bag 60. As shown in FIGS. 11 and 12, chow receptacle 111 of diet delivery system 96 holds wire food holder element 116. A further embodiment of the present invention in shown in FIGS. 10 and 12, wherein fluid bag receptacle 110 may be molded 110′ in order to facilitate the emptying of fluid 70 contained in fluid bag 60 by fluid delivery valve assembly 1 and to prevent the animal from gaining purchase on the fluid bag receptacle. In an alternate embodiment, fluid bag 60 is tapered or dimensioned so as to facilitate the emptying of fluid bag 60 by fluid delivery valve assembly 1. Fluid bag 60 may be made replaceable or disposable and thus may be manufactured singly in any quantity according to the needs of a user. Fluid delivery valve assembly 1 may be used to deliver the contents of fluid bag 60 to an animal in cage assembly 90. Fluid 70 in fluid bag 60 may include water, distilled water, water supplemented with various vitamins, minerals, medications such as antibiotics or anti-fungal agents, and/or other nutrients, or any fluid which is ingestible by a caged animal. Fluid 70 in fluid bag 60 is delivered to an animal in cage assembly 90 in a sterilized or sanitized condition so as to protect any animals in cage assembly 90 from contagion. Fluid bag 60 may be formed in any desirable shape or volume. In a preferred embodiment, fluid bag 60 is formed to fit fluid bag receptacle 110. Also, it should be clear that fluid bag 60 does not have to consist of a flexible material but that part thereof may be made of a rigid material. In an embodiment of the present invention, fluid bag 60 would consist of one or more layers, which would tear upon insertion of piercing member 11. Alternatively, flexible, stretchable, resilient plastic stickers 501 may be provided which can be adhered to the bag to prevent tearing thereof and to form a seal about the inserted piercing member 11. In addition, as depicted in FIGS. 13-15, fluid bag 60 could be made of a thinner plastic or inverted in the region where piercing edge 16 will penetrate fluid bag 60, thereby allowing the end user to readily identify where fluid bag 60 should be punctured and helping fluid bag 60 nest within fluid bag receptacle 110. In a further embodiment of the present invention, fluid bag 60 could be made of a resilient plastic or polymer material such that when piercing edge 16 penetrates fluid bag 60 at location 88, fluid bag 60 adheres to piercing member 16 so as to stop fluid 70 from leaking out of fluid bag 60. Fluid bag 60 may be constructed out of any material which is capable of being punctured by piercing member 16 and which is capable of holding fluid in a sterilized condition. In an embodiment of the invention, fluid bag 60 is plastic or any other flexible material capable of containing a fluid to be delivered to one or more laboratory animals. In a further embodiment of the present invention, fluid delivery valve assembly 1, upper member 10, fluid bag 60 and the contents thereof, fluid 70, are capable of being sterilized by one or more of an assortment of different means including but not being limited to: ultraviolet light, irradiation, chemical treatment, reverse osmosis, gas sterilization, steam sterilization, filtration, autoclave, and/or distillation. Each of the elements of the current invention, fluid delivery valve assembly 1, fluid bag 60 and fluid 70, can be sterilized or sanitized alone or in combination with each other. Fluid 70 of fluid bag 60 may be sterilized either before or after fluid bag 60 is sealed. In one embodiment providing a method of sterilization for the contents of fluid bag 60, a chemical compound capable of sterilizing the fluid 70, and known in the art, is put inside fluid bag 60 with fluid 70 prior to fluid bag 60 being sealed. Thereafter the compound sterilizes fluid 70 such that it can be delivered to an animal and consumed by that animal without harm. Other methods of sterilization are discussed below. In an embodiment of the invention, leak preventing member 501 is affixed or formed to upper member 10 and prevents a loss of fluid 70 from fluid bag 60 after puncture by piercing member 11. As shown in FIG. 14, piercing member 11 may be rigidly fixed to support element 50 of fluid bag receptacle 110 (see FIGS. 1 and 4), in particular in the support for the bag having its point directed upwards so that piercing member 11 is automatically inserted into fluid bag 60 at location 88 when placing fluid bag 60 onto support element 50 or into fluid bag receptacle 110′. In one embodiment of the present invention, fluid bag 60 is placed in fluid bag receptacle 110 of animal cage 90. Fluid bag receptacle 110 has a base 112, an inner surface 114 and an outer surface 115. Receptacle base 112 also defines actuation channel 400. When fluid delivery valve assembly 1 is used in conjunction with animal cage 90, stem 31 of trigger assembly 30 extends through cup 40 towards the interior of animal cage 90. In another embodiment, that portion of receptacle base 112 which encircles actuation channel 400 may include one or more locking members 51. As shown in FIG. 16, in an alternate embodiment, support member 50 may have four (or some other number of) locking members 51a, 51b, 51c and 51d formed thereon which may be used to secure flange members 13a, 13b, 13c and 13d to support member 50. It will be readily understood by one of ordinary skill in the art that flange members 13a, 13b, 13c and 13d may vary in shape, provided however, that flange members 13a, 13b, 13c and 13d are secured in fluid receptacle base 112 or onto support member 50 by its locking members 51a, 51b, 51c and 51d. In FIG. 16, locking members 51a, 51b, 51c and 51d are shaped like fingers and flange member 13 is divided into four equal pieces, shown as flange members 13a, 13b (not shown), 13c and 13d. Referring now to FIG. 17, an animal isolation and caging rack system 600 of the invention includes an open rack 615 having a left side wall 625 and a right side wall 630, a plurality of rack coupling stations 616, a top 635, and a bottom 640. A plurality of posts 645 are disposed in parallel between top 635 and bottom 640. Vertical posts 645 are preferably narrow and may comprise walls extending substantially from the front of rack 615 to the rear of rack 615, or may each comprise two vertical members, one at or near the front of rack 615 and the other at or near the rear of rack 615. Animal isolation and caging rack system 600 also includes a plurality of air supply plena 610 and air exhaust plena 620 alternately disposed in parallel between left side wall 625 and right side wall 630 in rack 615. The above discussed fluid delivery valve assembly 1, while facilitating the providing of fluid to animals, was found to have some deficiencies when used in conjunction with certain rack and cage system configurations. For example, with reference back to FIG. 3, when the stem 31 of the trigger assembly 30 is actuated by an animal, under certain circumstances, the stem may remain stuck in the open position even after the animal discontinues actuating the stem 31. If the stem remains stuck in the open position, fluid may continue to leak into the cage and cage bedding, with the result being a waste of fluid, and the potential for the animal to become hypothermic, or otherwise adversely affected. One reason for the occurrence of this problem in certain circumstances may be that due to the specific arrangement of the stem 31, sealing member 32 and spring element 20 within the fluid channel 14, when the stem 31 is actuated by an animal, the pivot point of upper end 33 of stem 31 about the bottom of spring element 20 tends not to be either predictable or consistent. Consequently, after actuation by an animal, stem 31, in certain circumstances, will shift position in relation to spring element 20, thus not allowing spring element 20 to bias stem 31 back into the desired closed position. With reference to FIG. 18, there is shown a fluid delivery valve assembly 200 that overcomes the above-discussed deficiency because, among other modifications, the arrangement of stem member 240, spring member 250, and sealing member 260 is different than that of their respective corresponding parts in fluid delivery valve assembly 1. This arrangement of stem member 240, spring member 250, and sealing member 260, discussed in detail below, provides for a predictable and consistent pivot point for stem member 240, thus facilitating a more consistent return to the closed position in the absence of actuation by an animal. Thus, fluid delivery valve assembly 200 is different in structure and arrangement to that of fluid delivery valve assembly 1 in several respects. However, in accordance with the present invention, fluid delivery valve assembly 200 may be used in all embodiments discussed above with reference to fluid delivery valve assembly 1. Accordingly, in any embodiment described herein that describes the use of fluid delivery valve assembly 1 in conjunction with, by way of non-limiting example, fluid bag 60, animal isolation and caging rack system 600, and/or diet delivery system 96, fluid delivery valve assembly 200 may be used as well, in accordance with the invention. With reference again to FIG. 18, there is shown fluid delivery valve assembly 200 having an upper member 210, and a base 220. Fluid delivery valve assembly 200 also includes sealing member 260, stem member 240, and spring member 250. Upper member 210 is formed with generally conical piercing member 211 having sharp point 214 for piercing fluid bag 60 as described above. One or more fluid apertures 215 are defined in a portion of piercing member 210, to facilitate the flow of fluid 70 from bag 60 into a fluid channel 216 defined within the piercing member 210. Upper member 210 is also formed with connecting member 212, having gripping portion 213 encircling a portion thereof. Base 220, being generally cylindrical in shape, includes top portion 221 and bottom portion 222, which are separated by flange member 226 which encircles base 220 and extends outwardly therefrom. Flange member 226 may be used to facilitate mounting or positioning of fluid delivery valve assembly 200 as is described above with regard to fluid delivery valve assembly 1. Top portion 221 may have an inner surface 223 with gripping portion 213 disposed thereon. Upper member 210 is designed and dimensioned to be coupled to base 220 with connecting member 212 being inserted into base top portion 221. The coupling may be facilitated by the frictional interaction of gripping portion 213 of upper member 210 with gripping portion 224 of base 220. Sealing member 260, stem member 240, and spring member 250 are disposed within base fluid channel 230. Stem member 240 has a top portion 241 that may be generally flat, such that flow aperture 265 of sealing member 260 may be advantageously sealed when a portion of bottom surface 262 of sealing member 260 is contacted by top surface 243 of stem member 240. Actuation portion 242 of stem member 240 extends through spring member 250 and through base fluid channel 230. Spring member 250 serves to bias stem member 240 against sealing member 260 to facilitate control of the flow of fluid, as described above with respect to fluid delivery valve assembly 1. With reference to FIG. 19, spring member 250 is retained within base fluid channel 230 at its bottom end as fluid channel 230 has narrow portion 232, which serves to block spring member 250 from passing through and out of fluid channel 230. The top of spring member 250 abuts the lower surface 244 (see FIG. 20) of stem member 240. Spring member 250 serves to bias stem member 240 in a vertical orientation, thus forming a seal between top surface 243 and sealing member 260. This seal may be facilitated by the use of lower ridge 266 to concentrate the biasing force of spring member 250 to form a seal against stem member 240. Turning to FIGS. 21 and 22, there is shown the operation of fluid delivery valve assembly 200 when stem member 240 is actuated by an animal. It should be noted that spring member 250 is not shown in FIGS. 21 and 22 for sake of clarity. During actuation of stem member 240 by an animal, however, as discussed above, spring member 250 provides a biasing force to bias stem member 240 toward a generally vertical position. With reference to FIG. 21, stem member 240 is positioned generally vertically, with top surface 243 of stem member 240 advantageously abutting lower ridge 266 of sealing member 260 at sealing point 246. The use of lower ridge 266 in conjunction with top surface 240 advantageously serves to focus and concentrate the biasing force of spring member 250 to form a seal as discussed above. Fluid delivery system 200 is shown having been punctured into fluid bag 60 such that fluid 70 may flow from fluid bag 60 into fluid aperture 215 of upper member 210, and in turn flow into fluid channel 216, through flow aperture 265 of sealing member 260, down to sealing point 246. At this point, with stem member 240 in the vertical (sealed) position, flow of the fluid is stopped. In an embodiment of the invention, bag 60, once punctured by fluid delivery valve assembly 200, should have its outer wall positioned in the range along surface 235 of top portion 201 of base 220 such that it remains disposed in the portion delimited at its upper bounds by bag retention wall 217 and at its lower bounds by flange top surface 227. In an embodiment of the invention, flow aperture 215 and (in some embodiments) aperture portion 218 may be advantageously positioned about an edge of bag retention wall 217. Turning now to FIG. 22, there is shown stem member 240 positioned as it would be while an animal actuates actuation portion 242 of stem member 240 in a direction B. Of course, one skilled in the art would recognize that the same result would be achieved so long as the stem member is actuated outwardly, out of its resting vertical position. Upon actuation in direction B, stem member 240 pivots about pivot point 236 such that top surface 243 of stem member 240 moves away from the lower ridge 266 of sealing member 260. This movement allows fluid 70 at flow aperture 265 of sealing member 260 to flow down through gap 237, into fluid channel 230, and out to the animal in the general direction A. Base 220 may be formed with abutment wall 233 disposed in fluid channel 230 such that the maximum travel of stem member 240 is limited such that the flow of fluid 70 is advantageously limited to a desired value. Additionally, stem member 240, base 220, sealing member 250 and spring member 250 may be advantageously designed and dimensioned such that stem member 240 pivots at a consistent and predictable pivot point 236 and will thus not be subject to sticking or jamming in the open position after stem member 240 is released from actuation by the animal. Consequently, the wasting of fluid and the exposure of animals to hypothermia or other problems caused by excessive wetting of the cage and bedding material may be minimized. Turning to FIG. 23, embodiments of the invention may be formed with base 220 of fluid delivery valve assembly 200 having extension portion 234. Extension portion 234 may serve, in certain application specific scenarios, to protect the actuation portion 242 of stem member 240 from being accidentally bumped by an animal, as only a portion of actuation portion 242 extends beyond extension portion 234. In an embodiment of the invention, the relative lengths L1 and L2 of extension portion 234 and actuation portion 242 may be adjusted based on the results desired, and the types of animals being fed, as well as other factors. Referring to FIG. 24, in an embodiment of the current invention water delivery system 1 (or fluid delivery valve assembly 200) is sterilized and/or autoclaved and maintained in a sterilized state prior to use in a wrapper 47 or other suitable container so as to avoid infecting an animal in animal cage 90 (while, for sake of brevity, the embodiments of the invention discussed below make specific reference only to fluid delivery valve assembly 1, it is to be understood that fluid delivery valve assembly 200 may also be used in all instances as well). When a user determines that a clean water delivery system is needed in conjunction with a fluid bag 60, water delivery system 1 is removed from wrapper 47 in sterile conditions or utilizing non-contaminating methods and inserted into animal cage 90 in fluid bag receptacle 110 (while it is contemplated that all of fluid delivery valve assembly 1 would be contained within wrapper 47, only a portion of fluid delivery valve assembly 1 is illustrated in FIG. 24). Thereafter fluid bag 60 is placed in fluid bag receptacle 110 and is punctured by piercing member 11 such that fluid 70 (i.e., water) is released through fluid channel 14 to an animal in animal cage 90. This procedure insures that sterilized fluid 70 is delivered through an uncontaminated fluid channel and that fluid delivery valve assembly 1 is itself uncontaminated and pathogen free. Additionally, in an embodiment of the invention, fluid delivery valve assembly 1 may be sold and stored in blister packs in groups of various quantities. Referring to FIG. 25, in another embodiment of the invention the upper portion of fluid delivery valve assembly 1, including upper member 10 and piercing member 11, is covered with a disposable cap 45, that can be removed when a user wants to use water delivery system 1 to pierce fluid bag 60 and place it in fluid bag receptacle 110 for delivery of a fluid to an animal in animal cage 90. Disposable cap 45 can be made from any suitable material and may be clear, color-coded to indicate the type of fluid in fluid bag 60, clear or opaque. Disposable cap 45 is easily removed from fluid delivery valve assembly 1. While cap 45 would not provide for a sterilized fluid delivery valve assembly 1, it would provide a labeling function, as well as, in an embodiment, provide protection from inadvertent stabbing of a user. An embodiment of the present invention provides a system and method for fluid delivery to one or more animal cages. The system provided has at least two methods of use, one which includes providing sealed sanitized bags of fluid for use in an animal cage or caging system. The provider provides the pre-packaged and uncontaminated fluid (e.g., water, or fluid with nutrients etc., as needed by an animal) for use preferably by delivering sanitized, fluid-filled, bags to a site designated by a user. Alternatively, the provider may locate a sealing apparatus, material for making the fluid bags and fluid supply at a location designated by the user. Thereafter, the provider will assemble, fill and seal the appropriate number of fluid bags for a user at the designated location. In a second method the provider provides a sealing apparatus and the material for making the fluid bags to a user. In this second method the provider may also supply any appropriate fluid to the user at a location designated by the user. The user thereafter assembles, fills and seals the fluid bags for use in the fluid delivery system of the invention as appropriate. A fluid bag filling and sealing method and system 300, in accordance with an embodiment of the invention, is illustrated in FIG. 26. Bag material 310, which may be formed of any suitable material as described above, is stored in bulk form, such as, for example, in roll form. As the process continues, bag material 310 is moved over bag forming portion 330 such that the generally flat shape of bag material 310 is formed into a tube. As the process continues, a vertical seal device 340 forms a vertical seal in bag material 310, thus completing the formation of a tube. Contents supply portion 320 serves to add ingredients, via, for example, gravity feed, into the tube of bag material 310. Contents supply portion 320 may include liquid and powder storage containers, and various pumps and other supply means, such that, for example, fluid 70, either with or without any additives as discussed above, may be added and metered out in appropriate quantities as is known in the art. Additionally, contents supply portion 320 may include heating and/or sterilizing equipment such that the contents supplied from contents supply portion 320 are in a generally sterilized condition. Next, horizontal seal device 350 forms a horizontal seal, either thermally, by adhesives, or by some other art recognized method as would be known to one skilled in the art. The horizontal seal serves to isolate the contents of the tube into separate portions. Next, the bag cutting device cuts the bag material at the horizontal seal to form individual fluid bags 60 containing fluid 70. Of course, in accordance with the spirit of the invention, the exact steps taken to form the fluid bags 60 may be varied as a matter of application specific design choice. In some embodiments of the invention steps may be added, left out, or performed in a different order. Additionally, the contents and bag material 310 of fluid bags 60 may be sterilized either before or after the completed bags are formed. In an embodiment of the invention, and with reference to FIGS. 27-29, the fluid 70 is heated to approximately 180° F., and the fluid bags are stacked in storage containers 370 with the result that the fluid 70, fluid bags 60 and storage containers all become sterilized to a satisfactory degree. In an embodiment of the invention, a cage body 98 may be used as such a storage container. Additional parts of this process may also be automated, as is shown by the use of robotic arm 380 in stacking containers. Storage containers 370 (or cage bodies 98) may also be supplied with fluid bags 60 at a workstation 382, before placement in a isolation and caging rack system 600. Additionally, storage containers 370 (or cage bodies 98) may be passed through various other sterilizing devices. With reference to FIG. 30, there is shown another embodiment of a fluid delivery valve assembly 400, which, as can be seen, is similar in many respects to fluid delivery valve assembly 200, described above. Through experimentation, it was found that an actuation force of 3 grams or less was optimal for allowing animals to obtain fluid from the valve assembly 400 efficiently and effectively. As described above with respect to fluid delivery valve assembly 200, the actuation force of actuating stem member 440 is related to the length of actuation portion 442 of stem member 440 (which acts as a lever as the top surface 443 of stem member 440 pivots upon sealing member 460), and the characteristics of spring member 450, which applies biasing force against stem member 440. To achieve this desired actuation force requirement, experiments were performed using various dimensions of the spring 460 (discussed below), base fluid channel 430, and stem member 440. Dimensions, for certain embodiments, were as follows: The width L3 of base fluid channel 430 was dimensioned to be about 0.205 in. The length of base fluid channel L4 (measured to the bottom of sealing member 460) was dimensioned be optimal about 0.300 in. With reference to FIG. 31, various dimensions with respect to stem member 440 were found to be beneficial. For example, the width L5 of top surface 443 of stem member 440 was dimensioned to be about 0.200 in. The length L6 of stem member 440 was dimensioned to be about 0.420 in. The height L7 of edge 445 of stem member 440 was dimensioned to be about 0.030 in. The thickness L8 of extension 447 of stem member 440 was dimensioned to be about 0.020 in. The depth L9 of stem cavity 446 was dimensioned to be about 0.025 in. The width L10 of stem cavity 446 was dimensioned to be about 0.100 in. Finally, the width L11 of actuation portion 442 of stem member 440 was dimensioned to be about 0.062 in. With reference to FIG. 32, there is illustrated an exemplary embodiment of spring member 450. Spring member 450 can be formed from 302 stainless steel wire with nickel coating, the wire having a diameter of 0.011 in. Outer diameter L13 can be about 0.188 in., and spring member 450 can have a free length L12 (length with no applied force) of 0.350 in. The load (or force generated by spring member 450) when compressed to a length of 0.255 in. (the approximate length of spring member 450 when housed within fluid delivery valve assembly 400) is 22.3 grams, within a range of plus or minus 3.5 grams. Of course, while certain embodiments have components dimensioned within the above limits, other dimensions may also be used, in accordance with the teachings herein. In certain embodiments, spring member 450 can have a total of about 19.4 coils, with about 6.4 of the coils being active, and about 13.4 of the coils being “dead coils.” Active coils 451 are coils that are free to deflect under a load. In contrast, a dead coil 452 is a coil of wire which does not contribute to the motive force of a spring. Generally, in extension and torsion springs, there are no dead coils. Typically, in compression springs, such as spring member 450, the coils at each end that lay against each other are dead coils, with the rest being active coils. In certain embodiments, however, additional dead coils 452 are employed to facilitate the assembly process. Specifically, because of the relatively small dimensions of spring member 450, the spring members 450 tend to nest and tangle when piled or grouped together as the active coils tend to become intertwined. In certain embodiments, however, dead coils 452 are advantageously employed to minimize the tangling of the spring members 450 during storage and assembly. In certain embodiments, groups 453 of dead coils 452 are positioned at various locations on spring member 450. In one embodiment, a group 453 of about 4.5 dead coils 453 is located at each end of spring member 450 and another grouping 453 of 4.5 dead coils 452 is located at the middle of spring member 450. Because the coils in the groupings 453 of dead coils 452 are positioned close together, coils from adjacent spring members 450 do not penetrate between the coils and the spring members 450 are less likely to tangle when piled or stored prior to assembly in fluid delivery valve assembly 400. In addition, the combination of spring member 450 dimensions described, in combination with the various dimensions described above with respect to stem member 440 and base 420 have been found to provide for a valve with an actuation force of 3 grams or less. To facilitate production of large quantities of fluid delivery valve assemblies 400, certain components, such as, for example, upper member 410, base 420 stem member 440, and sealing member 460, can be formed by way of an injection molding process. Generally, injection molding is the process of forcing melted plastic into a mold cavity. Once the plastic has cooled, the part can be ejected. With this process, many parts can be made at the same time, out of the same mold. With reference to FIG. 33, an exemplary injection molding apparatus 500 in accordance with certain embodiments is shown. In the injection molding process, resin 502 is fed to the apparatus through the hopper 504. The resins enter the injection barrel 506 by gravity though the feed throat 508. Upon entrance into the barrel 506, the resin 502 is heated by heating elements 510 to the appropriate melting temperature. The resin 502 is injected into the mold 512 by a reciprocating screw 514 or a ram injector. The reciprocating screw offers the advantage of being able to inject a smaller percentage of the total shot (amount of melted resin in the barrel). Typically, a screw 514 injector is better suited for producing smaller parts. The resin is moved through a runner to the outlet, or gate, and then into the mold cavity. The gate provides the connection between the runner and the molded part. The mold 512 receives the plastic and shapes it appropriately. The mold is cooled to a temperature that allows the resin to solidify and be cool to the touch. The mold plates 514 are held together by hydraulic or mechanical force. After sufficient part cooling, the mold is opened and the part 516 is ejected. The characteristics of the injection molded part are affected by three main categories of parameters: material parameters; geometry parameters; and manufacturing parameters. Material parameters include, among others, the viscosity of the material used and its associated pressure-volume-temperature behavior. Relevant geometry parameters include, among others, the wall thickness of the part, the number of gates from which the melted material passes into the mold, and the thickness of the gates. Some of the relevant manufacturing parameters include, among others, the mold temperature, the melt temperature of the material, and the pressure applied to the mold. The performance of an injection-molded part is dependent on the interaction of these groups of parameters, as would be understood by one of ordinary skill in the art, as instructed by the disclosure herein. In addition, while an embodiment of fluid delivery valve assembly 200 has been described herein as comprising a separate sealing member 260, and piercing member 210, these components can also be formed as a single component comprising sealing member 460 and upper member 410 integrally formed as a single component. Such an integrally formed component may be made by way of a multi-step molding process. Multi-step molding (or two-shot molding) requires a machine with two independent injection units, each of which injects a different material. The first material is injected through a primary runner system by a piston, as in a typical injection molding cycle. During this injection, the mold volume to be occupied by the second material is shut off from the primary runner system. The second runner system is then connected to the volume to be filled and the second material is injected. After sufficient part cooling, the mold is opened and the part is ejected. With reference to FIGS. 34 and 35, there is shown in FIG. 34 a plan view, and in FIG. 35, an elevation view of an exemplary mold 520 for integrally formed upper member 410 and sealing member 460. The mold 520 contains a plurality of cavities 522 in which the integral upper member 410 and sealing member 460 can be formed. The mold 520 is heated to a predetermined temperature, and a first material, in certain embodiments, polypropylene, is injected through the primary runner system 524 and out the primary gates 526 into the cavities 522 to form the upper member 410 portion of the integral component. Next, a cylinder at each cavity is retracted, thus opening a small secondary cavity 528 in the shape of sealing member 460. Next, a second material, in certain embodiments, silicone rubber, is injected through a secondary runner system into secondary cavity 528. As the materials cool, the upper member 410 and the sealing member 460 portion can, in certain embodiments, become chemically bonded. Next, the mold 520 components are separated and the integrally formed upper member 410 and the sealing member 460 components are ejected from the mold 520. With reference to FIG. 36, portions of the multi-step molding process 700 for the upper member 410 and sealing member 460 are described. First, the mold sections are closed. Step 710. Next, the first material is injected into the primary cavity, forming the upper member 410 portion. Step 720. Next, a cylinder is actuated and retracted, thus creating a secondary cavity in the shape of sealing member 460. Step 730. Next, the second material is injected into the newly formed secondary cavity, thus forming the sealing member 460 portion. Step 740. The combined integral component is then allowed to cool, the first and second materials forming a chemical bond. Step 750. Finally, the combined component is ejected from the mold. Accordingly, by way of this multi-step injection molding process, the upper member 410 can be integrally formed with sealing member 460, thus resulting in one less separate component during the valve assembly process. In certain embodiments, the base 420 and stem member 440 are also formed by injection molding. In addition, by having sealing member 460 integrally formed with upper member 410, the chances of sealing member 460 being misaligned during the assembly process are greatly minimized, thus providing for a larger amount of properly assembled valves. Further, by forming components of fluid delivery valve assembly 400 via injection molding, relatively large amounts of these components fluid delivery valve assemblies 400 can be produced, within precision tolerances, and with a relatively low failure rate. Moreover, a benefit of forming the fluid delivery valve assembly 400 by way of a multi-step injection molding process is that the fluid delivery valve assemblies 400 can be made relatively quickly, and inexpensively. In addition, the use of a spring having strategically place dead coils, thus preventing nesting of the springs during the manufacturing process, also contributes to the ability for the methods described herein to result in the manufacturing of a relatively inexpensive valve. Accordingly, because the fluid delivery valve assembly 400 is inexpensive, it is thus disposable. As such, the benefits of a disposable valve, such as no need for washing before reuse (because the valve assembly 400 is typically discarded after use), may be realized. Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to exemplary embodiments thereof, it would be understood that various omissions and substitutions and changes in the form and details of the disclosed invention may be made by those skilled in the art without departing from the spirit of the invention. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention that, as a matter of language, might be said to fall there between. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates generally to fluid delivery systems and in particular to a fluid delivery system and method for caging or storage systems for animals. 2. Description of Related Art A large number of laboratory animals are used every year in experimental research. These animals range in size from mice to non-human primates. To conduct valid and reliable experiments, researchers must be assured that their animals are protected from pathogens and microbial contaminants that will affect test results and conclusions. Proper housing and management of animal facilities are essential to animal well-being, to the quality of research data and teaching or testing programs in which animals are used, and to the health and safety of personnel. Ordinarily, animals should have access to potable, uncontaminated drinking water or other needed nutrient containing fluids according to their particular requirements. Water quality and the definition of potable water can vary with locality. Periodic monitoring for pH, hardness, and microbial or chemical contamination might be necessary to ensure that water quality is acceptable, particularly for use in studies in which normal components of water in a given locality can influence the results obtained. Water can be treated or purified to minimize or eliminate contamination when protocols require highly purified water. The selection of water treatments should be carefully considered because many forms of water treatment have the potential to cause physiologic alterations, changes in microflora, or effects on experimental results. For example, chlorination of the water supply can be useful for some species but toxic to others. Because the conditions of housing and husbandry affect animal and occupational health and safety as well as data variability, and effect an animal's well-being, the present invention relates to providing a non-contaminated, replaceable, disposable source of fluid for laboratory animals in a cage level barrier-type cage or integrated cage and rack system to permit optimum environmental conditions and animal comfort. Animal suppliers around the world have experienced an unprecedented demand for defined pathogen-free animals, and are now committed to the production and accessibility of such animals to researchers. Likewise, laboratory animal cage manufacturers have developed many caging systems that provide techniques and equipment to insure a pathogen free environment. For example, ventilated cage and rack systems are well known in the art. One such ventilated cage and rack system is disclosed in U.S. Pat. No. 4,989,545, the contents of which are incorporated herein by reference, assigned to Lab Products, Inc., in which an open rack system including a plurality of shelves, each formed as an air plenum, is provided. A ventilation system is connected to the rack system for ventilating each cage in the rack, and the animals therein, thereby eliminating the need for a cage that may be easily contaminated with pathogens, allergens, unwanted pheromones, or other hazardous fumes. It is known to house rats, for example, for study in such a ventilated cage and rack system. The increasing need for improvement and technological advancement for efficiently, safely housing and maintaining laboratory animals arises mainly from contemporary interests in creating a pathogen-free laboratory animal environment and through the use of immuno-compromised, immuno-deficient, transgenic and induced mutant (“knockout”) animals. Transgenic technologies, which are rapidly expanding, provide most of the animal populations for modeling molecular biology applications. Transgenic animals account for the continuous success of modeling mice and rats for human diseases, models of disease treatment and prevention and by advances in knowledge concerning developmental genetics. Also, the development of new immuno-deficient models has seen tremendous advances in recent years due to the creation of gene-targeted models using knockout technology. Thus, the desire for an uncontaminated cage environment and the increasing use of immuno-compromised animals (i.e., SCID mice) has greatly increased the need for pathogen free sources of food and water. One of the chief means through which pathogens can be introduced into an otherwise isolated animal caging environment is through the contaminated food or water sources provided to the animal(s). Accordingly, the need exists to improve and better maintain the health of research animals through improving both specialized caging equipment and the water delivery apparatus for a given cage. Related caging system technologies for water or fluid delivery have certain deficiencies such as risks of contamination, bio-containment requirements, DNA hazardous issues, gene transfer technologies disease induction, allergen exposure in the workplace and animal welfare issues. Presently, laboratories or other facilities provide fluid to their animals in bottles or other containers that must be removed from the cage, disassembled, cleaned, sterilized, reassembled, and placed back in the cage. Additionally, a large quantity of fluid bottles or containers must be stored by the labs based on the possible future needs of the lab, and/or differing requirements based on the types of animals studied. This massive storage, cleaning and sterilization effort, typically performed on a weekly basis, requires large amounts of time, space and human resources to perform these repetitive, and often tedious tasks. As such, a need exists for an improved system for delivering fluid to laboratory animals living in cage level barrier-type rack and cage systems. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention satisfies this need Briefly stated, in accordance with an embodiment of the invention, a fluid delivery system for delivering a fluid to an animal caging system for housing an animal is described. The fluid delivery system may comprise a fluid delivery valve assembly adapted to be coupled to a fluid bag holding a fluid. By advantageously using sanitized fluid bags, that may be disposable, the invention may minimize the need for the use of fluid bottles that typically must be removed from cages, cleaned, and sanitized on a frequent basis. The delivery system may be utilized in a single cage or in multiples cages integrated into ventilated cage and rack systems known in the art. An embodiment of the invention described herein provides for a fluid delivery system for delivering a fluid from a fluid bag to an animal caging system for housing an animal and may comprise a fluid delivery valve assembly, wherein the fluid delivery valve assembly is adapted to be coupled to the fluid bag to facilitate the providing of the fluid to an animal in the caging system. The fluid delivery valve assembly may further comprise an upper member having a piercing member and a connecting member, the upper member having a fluid channel defined therethrough, a base having a flange member and a base fluid channel defined therethrough, wherein the base is designed to be matingly coupled to the upper member. The fluid delivery valve assembly may further comprise a spring element disposed within the base fluid channel and a stem member disposed in part within the base fluid channel, wherein a portion of the spring element abuts the stem member to apply a biasing force. Another embodiment is directed to a method of forming a valve assembly for delivering a fluid from a fluid bag to an animal caging system for housing an animal can include forming, in an injection molding machine, an upper member having a piercing member and a connecting member. The upper member has a fluid channel defined therethrough; and forms, in an injection molding machine, a base having a flange member and a base fluid channel defined therethrough. The base is designed to be matingly coupled to the upper member. The method can further include forming, in an injection molding machine, a stem member designed and dimensioned to be disposed in part within the base fluid channel. The stem member has an actuation portion extending through a spring element. The stem member has a top portion having a lower surface. Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification. Other features and advantages of this invention will become apparent in the following detailed description of exemplary embodiments of this invention with reference to the accompanying drawings. | 20040413 | 20060117 | 20050203 | 92927.0 | 3 | MICHENER, JOSHUA J | FLUID DELIVERY VALVE SYSTEM AND METHOD | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,824,296 | ACCEPTED | OBDII readiness status notification device | A device for notifying an operator of the readiness of a vehicle for emissions testing includes a control logic for evaluating the status of each of a plurality of the monitors of an on-board diagnostics (OBDII) system of the vehicle. Once the vehicle is determined to be ready for emissions testing based on the status of each evaluated monitor of the OBDII system, an indicator light is illuminated and/or an audio signal is emitted to notify the operator. | 1. A device for notifying an operator of the readiness of a vehicle for emissions testing, comprising: a housing containing a control logic for evaluating the status of each of a plurality of the monitors of an on-board diagnostics (OBDII) system of the vehicle; a connection port adapted to mate with the diagnostic link connector of the OBDII system, placing the control logic in electrical communication with the OBDII system; and an indicator for notifying the operator when the vehicle is determined to be ready for emissions testing based on the status of each evaluated monitor of the OBDII system. 2. The device of claim 1, in which the indicator is a light that is illuminated when the vehicle is determined to be ready for emissions testing. 3. The device of claim 1, in which the indicator is an audio signal emitted by the device when the vehicle is determined to be ready for emissions testing. 4. The device of claim 1, wherein the vehicle is considered ready for emissions testing when less than a predetermined number of the monitors report a status of “not ready.” 5. The device of claim 4, and further comprising a selector switch allowing the operator to establish the value of the predetermined number of the monitors that may report a status of “not ready.” 6. The device of claim 1, and further comprising a selector switch allowing the operator to indicate whether the catalyst monitor must be reporting as “ready” in order for the vehicle to be considered ready for emissions testing. 7. The device of claim 5, and further comprising a selector switch allowing an operator to indicate whether the catalyst monitor must be reporting as “ready” in order for the vehicle to be considered ready for emissions testing. 8. The device of claim 1, in which the indicator includes both a light that is illuminated when the vehicle is determined to be ready for emissions testing, along with an audio signal emitted by the device when the vehicle is determined to be ready for emissions testing. 9. The device of claim 8, and further comprising a selector switch allowing an operator to indicate whether the light is illuminated, the audio signal is emitted, or both when the vehicle is determined to be ready for emissions testing. 10. The device of claim 1, and further comprising a plurality of individual indicator lights, each indicator light corresponding to a particular evaluated monitor, and each indicator light being illuminated when the corresponding monitor is reporting as “ready” or “unsupported.” 11. A method for determining when a vehicle is ready for emissions testing and notifying an operator of the same, comprising the steps of: continuously evaluating the monitors of an on-board diagnostics (OBDII) system of the vehicle through a device connected to the diagnostic link connector of the OBDII system; counting the number of monitors reporting as “not ready”; and notifying the operator when the number of monitors reporting as “not ready” is less than or equal to a predetermined threshold. 12. The method of claim 11, wherein the step of notifying the operator is achieved through a visual indicator light on a surface of the device that is illuminated when the number of monitors reporting as “not ready” is less than or equal to the predetermined threshold. 13. The method of claim 11, wherein the step of notifying the operator is achieved through an audio signal emitted by the device when the number of monitors reporting as “not ready” is less than or equal to the predetermined threshold. 14. The method of claim 11, wherein the device connected to the diagnostic link connector includes a selector switch which allows the operator to establish the predetermined threshold. 15. The method of claim 11, wherein the device connected to the diagnostic link connector includes a plurality of individual indicator lights, each indicator light corresponding to a particular evaluated monitor, and each indicator light being illuminated when the corresponding monitor is reporting as “ready” or “unsupported.” 16. A method for determining when a vehicle with an on-board diagnostics (OBDII) system is ready for electronic interrogation of the OBDII system as part of an emissions inspection, comprising the steps of: connecting a notification device to the OBDII system, said notification device having a control logic capable of evaluating the status of one or more monitors of the OBDII system; evaluating the status of said one or monitors of the OBDII system; and notifying an operator when the control logic of the notification device determines that the vehicle is ready for the electronic interrogation of the OBDII system based upon its evaluation of the monitors of the OBDII system. 17. The method of claim 16, wherein the step of notifying the operator is achieved through a visual indicator light on a surface of the notification device that is illuminated when the number of monitors reporting as “not ready” is less than or equal to a predetermined threshold. 18. The method of claim 17, wherein the notification device includes a selector switch which allows the operator to establish the predetermined threshold. 19. The method of claim 16, wherein the step of notifying the operator is achieved through an audio signal emitted by the notification device when the number of monitors reporting as “not ready” is less than or equal to a predetermined threshold. 20. The method of claim 19, wherein the notification device includes a selector switch which allows the operator to establish the predetermined threshold. 21. The method of claim 16, wherein the notification device includes a plurality of individual indicator lights, each indicator light corresponding to a particular evaluated monitor, and each indicator light being illuminated when the corresponding monitor is reporting as “ready” or “unsupported.” | BACKGROUND OF THE INVENTION The present invention relates to vehicle emissions testing, and, more particularly, to a device that notifies a vehicle operator that the vehicle is ready for an emissions inspection. Recognizing the adverse effects that vehicle emissions have on the environment, the 1990 Clean Air Act requires that communities in geographic regions having high levels of air pollution implement Inspection and Maintenance (“I/M”) programs for vehicles in the particular geographic regions. Such I/M programs are intended to improve air quality by periodically testing the evaporative and exhaust emissions control systems of vehicles in the community and ensuring their proper operation and maintenance. By ensuring that the evaporative and exhaust emissions control systems of vehicles are operational and properly maintained, air pollution resulting from vehicle emissions in the geographic region should be drastically reduced. I/M programs in the United States typically employ some method of “tailpipe” testing as the primary means of inspection. Although there are several variations of common tailpipe testing, the core function of tailpipe testing remains the same. First, a probe is attached to, or inserted into, the tailpipe of the vehicle being tested to collect exhaust as the engine of the vehicle is running. The collected exhaust is then introduced into a series of gas analyzers in order to determine its composition. Finally, a report of the amount of measured pollutants is generated. In 1992, the California Air Resources Board (CARB) proposed regulations for the monitoring and evaluation of a vehicle's emissions control system through the use of second-generation on-board diagnostics (“OBDII”). (See California Code of Regulations, Title 13, 1968.1—Malfunction and Diagnostic Systems Requirements—1994 and subsequent model year passenger cars, light-duty trucks, and medium-duty vehicles with feedback fuel control systems.) These regulations were later adopted by the United States Environmental Protection Agency. (See Environmental Protection Agency, 40 C.F.R. Part 86—Control of Air Pollution From New Motor Vehicles and New Motor Vehicle Engines; Regulations Requiring On-Board Diagnostic Systems on 1994 and Later Model Year Light-Duty Vehicles and Light-Duty Trucks.) As a result, OBDII systems were required to be phased in beginning in 1994, and by 1996, almost all light-duty, gasoline-powered motor vehicles in the United States were required to have OBDII systems. In general, through the use of OBDII systems, the emissions control system of a vehicle is constantly monitored, with a “check engine” light or Malfunction Indicator Light (MIL) on the dashboard of the vehicle being illuminated to inform the operator of a problem with the emissions control systems. The OBDII system is commonly interrogated as part of I/M programs to ensure it is functioning properly. Discussing now the more specific operational details, OBDII systems are designed to monitor certain emissions control systems, i.e., groupings of related vehicle emissions components, to ensure they are functioning properly. Each such emissions control system is evaluated by a “monitor,” which also may be referred to as an “OBDII monitor” or a “readiness monitor.” CARB designates eleven monitors that the OBDII system of a vehicle may be required to evaluate: TABLE A MONITOR TYPE Fuel Metering/Trim Continuous Misfire Continuous Comprehensive Continuous Component Air Conditioning Unsupported Catalyst Heater Unsupported Catalyst Non-continuous Oxygen Sensor Non-continuous Oxygen Sensor Heater Non-continuous Evaporative Emissions Non-continuous Control System Secondary Air Non-continuous Exhaust Gas Recirculation Non-continuous As indicated in Table A, the first three monitors are “continuous” in that evaluation of the particular emissions control system is ongoing at any time the vehicle engine is operating. For this reason, these three monitors are always reported by the OBDII system as being “ready,” meaning that the system has been evaluated. In this regard, it is important to recognize that a status of “ready” does not mean that the particular emissions control system is operating properly, but only that the system has been evaluated. If a particular vehicle emissions system has been evaluated, and a fault is found with the system, the check engine light or MIL will be illuminated. Referring still to Table A, although identified in the applicable regulations, the air conditioning and catalyst heater monitors are not included in most vehicles and are therefore reported by the OBDII system as “unsupported.” Finally, the remaining six monitors are characterized as “non-continuous” because if the vehicle supports them, functionality of the particular emissions control system can only be evaluated after the vehicle has been operating for a predetermined time period or until certain conditions are satisfied. Accordingly, a non-continuous monitor will be reported by the OBDII system as “not ready” until the predetermined time period has elapsed or the certain conditions have been satisfied. For example, assuming a non-continuous monitor is supported, the monitor will have a status of “not ready” when the vehicle is brand new (since the monitor has not yet had an opportunity to evaluate the emissions control system), if the battery has been disconnected for a period of time (such that computer memory is cleared), or if a technician performs specific operations on the OBDII system. After the vehicle has been operated until the predetermined time period has elapsed or the certain conditions have been satisfied, each monitor will evaluate its emissions control system, and the status of each monitor will then be reported as “ready.” The status continues to be reported as “ready” until reset by a technician or the battery of the vehicle is disconnected. For example, the catalyst monitor evaluates whether the catalyst is functioning properly. This is generally accomplished through the use of two oxygen sensors, one upstream of the catalyst and one downstream of the catalyst. On a properly operating vehicle, the engine will vary from operating slightly lean (excess oxygen) to slightly rich (excess fuel). A common three-way catalyst, a catalyst that reduces the levels of hydrocarbons, carbon monoxide, and oxides of nitrogen, captures and stores the excess oxygen in the exhaust during the slightly lean periods, and then uses that oxygen during the periods of slightly rich operation to oxidize the hydrocarbons to carbon dioxide and water and to oxidize the carbon monoxide to carbon dioxide. Therefore, if a catalyst is functioning properly, the oxygen sensor upstream of the catalyst should measure a fluctuation in the oxygen content in the exhaust, but the downstream oxygen sensor should measure a much lower fluctuation in the oxygen content in the exhaust (since the oxygen is being absorbed by the catalyst and then converted into other molecules before passing the downstream oxygen sensor). If, however, the upstream and downstream sensors measure the same fluctuation in the oxygen content in the exhaust gas, it is an indication that the catalyst is not storing the excess oxygen and is therefore probably not oxidizing the hydrocarbons and carbon monoxide. Accordingly, the OBDII system may activate the check engine light to notify the vehicle operator that there is a problem with this emissions control system. However, the catalyst functions properly only under specific conditions, and thus, the OBDII catalyst monitor often cannot immediately evaluate the catalyst after the OBDII memory is cleared and the catalyst monitor is reset to “not ready.” For instance, if the catalyst is cold, or if one of the oxygen sensors is not functioning properly, then the system cannot evaluate the catalyst function. Until the catalyst is in condition to be evaluated, the catalyst monitor will report a status of “not ready.” Once the appropriate conditions have been satisfied, the catalyst is evaluated, and the catalyst monitor is reported as “ready.” In the past, I/M programs have often included under-hood visual and functional inspections of emissions control components combined with tailpipe emissions tests to determine if the emissions control systems of a vehicle are functioning properly. However, in recent years, an increasing number of I/M programs have been inspecting 1996 and newer vehicles by using electronic interrogation of the OBDII system to determine if the emissions control systems of a vehicle are functioning properly. Such testing is described in detail in “Performing Onboard Diagnostic System Checks as Part of a Vehicle Inspection and Maintenance Program,” EPA 420-R-01015 (June 2001), a report that is incorporated herein in its entirety by this reference. However, if the battery of a vehicle is disconnected for a period of time, the OBDII system memory is cleared. If there was a fault previously identified by the OBDII system that caused the MIL to be illuminated, it will also be cleared. If the vehicle is tested in an I/M program via the OBDII system shortly after having the battery disconnected, the OBDII system may now appear not to have a problem because the OBDII system may not have had a chance to find the fault again before the I/M OBDII emissions inspection. Furthermore, I/M program regulations typically require service technicians to clear the OBDII memory after repairs are performed. This is done so that when the OBDII system of the vehicle is checked after the repair to determine if the problem has been appropriately remedied, it is clear if the monitor for the system that was repaired has run and checked the repaired system. Again, if a particular system has been evaluated, it will be reported as “ready.” If it has not been evaluated, it will be reported as “not ready.” Because unscrupulous vehicle operators, recognizing that there is a problem with an emissions control system because the MIL is illuminated, could attempt to conceal a known defect by disconnecting the battery to clear the OBDII system memory, I/M programs require a check of the readiness monitors to verify that the OBDII system has evaluated the emissions control systems. Because of the check for readiness, if the battery was disconnected just before the test to clear an illuminated MIL, various monitors will be reported as “not ready,” and thus, the vehicle will not be allowed to pass the I/M OBDII emissions inspection. Furthermore, it is possible that through normal operation, all of the monitors in a vehicle may not be set to “ready.” Therefore, the EPA has suggested in its guidance on performing I/M OBDII emissions inspections that vehicles with model years of 1996-2000 should be considered ready if two or fewer of the non-continuous monitors are “not ready.” For 2001 and newer vehicles, one non-continuous monitor may be reported as “not ready.” Furthermore, in a few states, three monitors are allowed to be “not ready,” and the vehicle is still considered ready for the OBDII I/M emissions inspection. As mentioned above, if a vehicle fails an I/M OBDII emissions inspection and is repaired, the OBDII memory will be cleared and monitors will be reset to “not ready.” Since the vehicle cannot pass an emissions inspection until only a few monitors of the OBDII system are reporting their status as “not ready,” the technician may instruct the vehicle operator to drive the vehicle for a period of time and then return so the technician can check to see if the vehicle is ready to be tested. Because the technician cannot tell the vehicle operator how long they should drive the vehicle to get it ready, and vehicle operators are not pleased to return for an inspection only to discover that too many monitors are still reporting their status as “not ready,” there is a need for a device that can communicate to and notify a vehicle operator that a vehicle is ready for an I/M OBDII emissions inspection. SUMMARY OF THE INVENTION The present invention is a device that notifies a vehicle operator that the vehicle is ready for an I/M OBDII emissions inspection. In one exemplary embodiment, the notification device includes a housing that encloses a circuit board with a control logic responsible for the function and operation of the notification device. At one end of the housing, there is a connection port designed to mate with the Diagnostic Link Connector (DLC) of a vehicle, placing the control logic of the notification device in electrical communication with the OBDII system of the vehicle. At the other end of the housing, there are preferably two indicator lights, a first indicator light being illuminated to indicate that the vehicle is not ready for an I/M OBDII emissions inspection, and the second light being illuminated when the vehicle is ready for an I/M OBDII emissions inspection. In operation, the control logic of the notification device evaluates the status of a plurality of the respective monitors of the OBDII system. Based on such an evaluation, and specifically a count of the number of monitors reporting as “not ready,” the notification device will either illuminate the “not ready” light if the vehicle is not ready for an I/M OBDII emissions inspection, or the “ready” light if the vehicle is ready for an I/M OBDII emissions inspection. Additionally, the notification device may have a speaker to emit an audio signal, in lieu of or in addition to the visual indicator, when the OBDII system of the vehicle is ready for an I/M OBDII emissions inspection. As a further refinement, the notification device may also include two selector switches on a surface of the housing. The first selector switch allows an operator to indicate the number of readiness monitors of the OBDII system that will be allowed to be reported as “not ready,” while still allowing the device to report the vehicle as being ready to be tested. The second selector switch allows an operator to indicate whether the catalyst monitor must be reporting as “ready” in order for the notification device to report the vehicle as being ready to be tested. As yet a further refinement, the notification device may also include a third selector switch used to indicate how the notification device will notify the vehicle operator when the OBDII system of the vehicle is ready for an I/M OBDII emissions inspection. In this regard, the selector switch can be set to “audio,” and the notification device will emit an audio signal when the vehicle is ready for an I/M OBDII emissions inspection. Alternatively, the selector switch can be set to “visual,” and the notification device will illuminate the “not ready” light if the vehicle is not ready for an I/M OBDII emissions inspection. Once the vehicle is ready for an I/M OBDII emissions inspection, the notification device will then illuminate the “ready” light. If the selector switch is set to “both,” then both the audio and visual signaling techniques will be used when the vehicle is ready for an I/M OBDII emissions inspection. As yet a further refinement, the notification device may include six additional indicator lights, each of which corresponds to a particular non-continuous monitor of the OBDII system. When a monitor has been checked and is reporting as “ready” or “unsupported,” the corresponding indicator light is illuminated to notify the operator of the status of that particular monitor. DESCRIPTION OF THE FIGURES FIG. 1 is a plan view of the face of an exemplary notification device made in accordance with the present invention; FIG. 2 is an end view of the exemplary notification device of FIG. 1; FIG. 3 is a second end view of the exemplary notification device of FIG. 1; FIGS. 4-6 are flow charts illustrating the function and operation of the exemplary notification device of FIG. 1; FIG. 7 is a plan view of the face of a second exemplary notification device made in accordance with the present invention; FIG. 8 is an end view of the second exemplary notification device of FIG. 7; FIG. 9 is a second end view of the second exemplary notification device of FIG. 7; and FIGS. 10-11 are flow charts illustrating the function and operation of the exemplary notification device of FIG. 7. DETAILED DESCRIPTION OF THE INVENTION The present invention is a device that notifies a vehicle operator that the vehicle is ready for an I/M OBDII emissions inspection. FIGS. 1-3 are views of an exemplary notification device 10 made in accordance with present invention. The notification device 10 is generally comprised of a housing 12 that encloses a circuit board with a control logic (as illustrated in phantom and indicated by reference numeral 13) responsible for the function and operation of the notification device 10, as will be further discussed below. At one end of the housing 12, as best shown in FIG. 2, there is a connection port 14 designed to mate with the Diagnostic Link Connector (DLC) of a vehicle, placing the control logic 13 of the notification device 10 in electrical communication with the OBDII system of the vehicle. The DLC is also the connection point for an OBD scanning device for interrogating the OBDII system, and the DLC is usually located beneath the dashboard on the driver's side of the vehicle, or in a similar, reasonably accessible location. At the other end of the housing 12, there are preferably two indicator lights 16, 18, a first indicator light 16 being illuminated to indicate that the vehicle is not ready for an I/M OBDII emissions inspection, and the second light 18 being illuminated when the vehicle is ready for an I/M OBDII emissions inspection, as will be further discussed below. Finally, in this exemplary embodiment, there are two selector switches 20, 22 and a speaker 26 on the front surface of the housing 12. The first selector switch 20 allows an operator to indicate the number of readiness monitors of the OBDII system that will be allowed to be reported as “not ready,” while still allowing the emissions inspection to proceed. For example, the second selector switch 20 can be set so that the notification device 10 will indicate the vehicle is ready for an I/M OBDII emissions inspection when: (a) all of the monitors are reporting as “ready,” i.e., a setting of “0”; (b) only one monitor is reporting as “not ready,” i.e., a setting of “1”; (c) two monitors are reporting as “not ready,” i.e., a setting of “2”; or (d) three monitors are reporting as “not ready,” i.e., a setting of “3.” The second selector switch 22 allows an operator to indicate whether the catalyst monitor must be reporting as “ready” in order for the notification device 10 to report the vehicle as being ready to be tested. In this regard, some inspection authorities require that the catalyst monitor be functioning properly regardless of the monitor count described above. Thus, if the selector switch 22 is set to “yes,” then the catalyst monitor must be reporting as “ready” for the notification device 10 to consider the vehicle ready for an I/M OBDII emissions inspection. However, if the selector switch 22 is set to “no,” then the status of the catalyst monitor is not separately considered in determining if the vehicle is ready for an I/M OBDII emissions inspection. The notification device 10 will thus illuminate the “not ready” light 16 (which is preferably red in color) if the vehicle is not ready for an I/M OBDII emissions inspection. Once the vehicle is ready for an I/M OBDII emissions inspection, the “not ready” light 16 will be extinguished, and the notification device 10 will illuminate the “ready” light 18 (which is preferably green in color). Furthermore, in this exemplary embodiment, when the OBDII system of the vehicle is ready for an I/M OBDII emissions inspection, the notification device 10 will also emit an audio signal through the speaker 26. Alternatively, such an audio signal could be emitted through the vehicle radio, for example, by transmitting the audio signal through the power line of the OBDII system to the radio, without departing from the spirit and scope of the present invention. Referring now to the flow charts of FIGS. 4-6, the exemplary notification device 10 described above operates as follows. As should be clear from the above description, the connection port 14 of the notification device 10 is inserted into and mated with the Diagnostic Link Connector (DLC) of the vehicle as indicated by block 200 of FIG. 4, the same connector used for connection an OBD scanning device for interrogating the OBDII system. The notification device 10 draws power from the vehicle through one of the connector pins (commonly, pin 16), as indicated by block 202, and thus once powered, the notification device 10 sequentially attempts communication via one of the five standard OBDII communications protocols, as illustrated by decisions 204, 206, 208, 210, 212 of FIG. 4. Specifically, the five standard OBDII communications protocols, each of which is known to and understood by one of ordinary skill in the art, are as follows: (1) SAE J1850 Variable Pulse Width (“VPW”) Modulation; (2) SAE J1850 Pulse Width Modulation (“PWM”); (3) ISO 9141-2 (“ISO”); (4) ISO 14230-4 (“Key Word Protocol 2000” or “KWP 2000”); and (5) SAE J2284 (“Controller Area Network” or “CAN”) and also defined in ISO WD 15765-4 and ISO DIS 15031-5. If communication cannot be established, in this exemplary embodiment, the notification device 10 will illuminate both the “not ready” light 16 and the “ready” light 18 (shown in FIGS. 1 and 3), as indicated at block 214 of FIG. 4. Of course, other visual and/or audio cues could be used to notify the operator that communication can not be established without departing from the spirit and scope of the present invention. In any event, in this exemplary embodiment, the notification device 10 waits for a predetermined time period (e.g., two minutes), as indicated at block 216 of FIG. 4, and then re-attempts to establish communication, again via one of the five standard OBDII communications protocols. Referring now to the flow chart of FIG. 5, once communication is established, a readiness counter, N, is set at zero, meaning that none of the non-continuous monitors have yet been checked or verified as “ready,” as indicated at block 220 of FIG. 5. Then, the notification device 10 electronically requests the readiness status of each of the six non-continuous OBDII monitors per SAE J1979, a well-known protocol commonly used by manufactures of OBD scanning tools. These requests are illustrated by decisions 222, 226, 230, 234, 238 and 242 of FIG. 5. For example, in the methodology illustrated in FIG. 5, the catalyst monitor is the first monitor to be checked to determine if it is “ready” (or “unsupported”). If so, the readiness counter is incremented by a value of one (N=N+1), as indicated at block 224 of FIG. 5, and then, the next monitor is checked. In this example, that second monitor is the exhaust gas recirculation monitor. If this monitor is reporting as “ready” (or “unsupported”), the readiness counter again is incremented by a value of one (N=N+1), as indicated at block 228 of FIG. 5, and then, the next monitor is checked. This process continues until all six non-continuous monitors have been checked. Of course, if a particular monitor is reporting as “not ready,” no value is added to the readiness counter. Referring now to FIG. 6, once all non-continuous monitors have been checked, the readiness counter will have a value, N, equal to the number of monitors that were reporting as “ready” or “unsupported.” Accordingly, the value 6−N represents the number of non-continuous monitors that were reporting as “not ready.” Thus, at decision 250, the value 6−N is compared to the value established by the selector switch 20 (as described above with reference to FIG. 1). If the value 6−N is less than or equal to the value established by the selector switch 20, the vehicle is ready for an I/M OBDII emissions inspection, at least with respect to the number of monitors that can be reported as “not ready.” If the selector switch 22 (as also described above with reference to FIG. 1) is set to “yes,” as indicated at decision 252 of FIG. 6, then another determination must be made. Specifically, as indicated at decision 254, the notification device 10 independently checks whether the catalyst monitor is reporting as “ready,” and if so, the vehicle is ready for an I/M OBDII emissions inspection. Accordingly, the “ready” light 18 (as shown in FIGS. 1 and 3) is illuminated, as indicated at block 256, and the “not ready” light 16 (as also shown in FIGS. 1 and 3) is extinguished, as indicated at block 258. Then, an audio signal is also emitted, as indicated at block 260. Finally, as illustrated in the flow chart of FIG. 6, after a predetermined time period (e.g., two minutes), as indicated at block 262, the process is re-initiated with the notification device 10 again electronically requesting the readiness status of each of the six non-continuous OBDII monitors. Referring still to FIG. 6, if the value 6−N is greater than the value established by the selector switch 20 at decision 250, or if the catalyst monitor is required to be “ready” and is reporting as “not ready” at decisions 252, 254, then the vehicle is not ready for an I/M OBDII emissions inspection. Accordingly, the “not ready” light 16 (as shown in FIGS. 1 and 3) is illuminated, as indicated at block 264, and the “ready” light 18 (as also shown in FIGS. 1 and 3) is extinguished, as indicated at block 266. Then, after a predetermined time period (e.g., two minutes), as indicated at block 262, the process is re-initiated with the notification device 10 again electronically requesting the readiness status of each of the six non-continuous OBDII monitors. FIGS. 7-9 are views of a second exemplary notification device 110 made in accordance with present invention. The notification device 110 is constructed in manner substantially identical to that of the exemplary embodiment described above with reference to FIGS. 1-3, generally comprising a housing 112 that encloses a circuit board with a control logic (as illustrated in phantom and indicated by reference numeral 113) responsible for the function and operation of the notification device 110. At one end of the housing 112, as best shown in FIG. 8, there is a connection port 114 designed to mate with the DLC of a vehicle, placing the control logic 113 of the notification device 110 in electrical communication with the OBDII system of the vehicle. At the other end of the housing 12, there are preferably two indicator lights 116, 118, a first indicator light 116 being illuminated to indicate that the vehicle is not ready for an I/M OBDII emissions inspection, and the second light 118 being illuminated when the vehicle is ready for an I/M OBDII emissions inspection. There are also six additional indicator lights, collectively indicated by reference numeral 128 in FIG. 9, each of which corresponds to a particular non-continuous monitor. Furthermore, in this exemplary embodiment, there are three selector switches 120, 122, 124 and a speaker 126 on the front surface of the housing 112. As with the exemplary embodiment described above with reference to FIGS. 1-3, the first selector switch 120 allows a operator to indicate the number of readiness monitors of the OBDII system that will be allowed to be reported as “not ready,” while still allowing the emissions inspection to proceed, and the second selector switch 122 allows an operator to indicate whether the catalyst monitor must be reporting as “ready” in order for the notification device 110 to report the vehicle as being ready to be tested. Lastly, in this exemplary embodiment, the third and final selector switch 124 is used to indicate how the device 110 should notify the vehicle operator when the OBDII system of the vehicle is ready for an I/M OBDII emissions inspection. In this regard, the selector switch 124 can be set to “audio,” and the notification device 110 will emit an audio signal through the speaker 126 when the vehicle is ready for an I/M OBDII emissions inspection. Alternatively, the selector switch 124 can be set to “visual,” and the notification device will illuminate the “not ready” light 116 (which is preferably red in color) if the vehicle is not ready for an I/M OBDII emissions inspection. Once the vehicle is ready for an I/M OBDII emissions inspection, the “not ready” light 116 will be extinguished, and the notification device 110 will illuminate the “ready” light 118 (which is preferably green in color). If the selector switch 124 is set to “both,” then both the audio and visual signaling techniques will be used when the vehicle is ready for an I/M OBDII emissions inspection. Referring again to the flow chart of FIG. 4, as with the exemplary embodiment of the notification device 10 described above with reference to FIG. 1-3, the connection port 114 of the notification device 110 is inserted into and mated with the DLC of the vehicle and then attempts communication via one of the five standard OBDII communications protocols. Referring now to FIG. 10, once communication is established, this exemplary notification device 110 operates as follows. First, the six additional indicator lights, which are collectively indicated by reference numeral 128 in FIG. 9, are extinguished, as indicated at block 319 of FIG. 10. Furthermore, a readiness counter, N, is again set at zero, as indicated at block 320 of FIG. 10. Then, the notification device 110 electronically requests the readiness status of each of the six non-continuous OBDII monitors per SAE J1979, as illustrated by decisions 322, 326, 330, 334, 338 and 342 of FIG. 10. For example, in the methodology illustrated in FIG. 10, the catalyst monitor is the first monitor to be checked to determine if it is “ready” or “unsupported.” If so, the readiness counter is incremented by a value of one (N=N+1), as indicated at block 324 of FIG. 10. Furthermore, if the selector switch 124 (as described above with reference to FIG. 7) is set to “visual” or “both,” as evaluated at decision 323, the indicator light 128 associated with the catalyst monitor (as shown in FIGS. 7 and 9) is illuminated to provide the operator with immediate visual notification that the monitor has been checked and is reporting as “ready” or “unsupported,” as indicated at block 325. Each monitor is checked in this manner. Of course, if a particular monitor is reporting as “not ready,” no value is added to the readiness counter, and the associated indicator light 128 is not illuminated. Referring now to FIG. 11, once all non-continuous monitors have been checked, the readiness counter will have a value, N, equal to the number of monitors that were reporting as “ready” or “unsupported.” Accordingly, the value 6−N represents the number of non-continuous monitors that were reporting as “not ready.” Thus, at decision 350, the value 6−N is compared to the value established by the selector switch 120 (as described above with reference to FIG. 7). If the value 6−N is less than or equal to the value established by the selector switch 120, the vehicle is ready for an I/M OBDII emissions inspection, at least with respect to the number of monitors that can be reported as “not ready.” If the selector switch 122 (as described above with reference to FIG. 7) is set to “yes,” as indicated at decision 352 of FIG. 6, then another determination must be made. Specifically, as indicated at decision 354, the notification device 110 independently checks whether the catalyst monitor is reporting as “ready,” and if so, the vehicle is ready for an I/M OBDII emissions inspection. Accordingly, if the selector switch 124 (as described above with reference to FIG. 7) is set to “visual” or “both,” as evaluated at decision 355, the “ready” light 118 (as shown in FIGS. 7 and 9) is illuminated, as indicated at block 356, and the “not ready” light 116 (as also shown in FIG. 9) is extinguished, as indicated at block 358. Then, if the selector switch 124 is set to “audio” or Finally, as illustrated in the flow chart of FIG. 11, after a predetermined time period (e.g., two minutes) as indicated at block 362, the process is re-initiated with the notification device 110 again electronically requesting the readiness status of each of the six non-continuous OBDII monitors. Referring still to FIG. 11, if the value 6−N is greater than the value established by selector switch 120 at decision 350, or if the catalyst monitor is required to be “ready” and is reporting as “not ready” at decisions 352, 354, then the vehicle is not ready for an I/M OBDII emissions inspection. Accordingly, if the selector switch 124 is set to “visual” or “both,” as evaluated at decision 363, the “not ready” light 116 (as shown in FIGS. 7 and 9) is illuminated, as indicated at block 364, and the “ready” light 118 (as also shown in FIGS. 7 and 9) is extinguished, as indicated at block 366. Then, after a predetermined time period (e.g., two minutes) as indicated at block 362, the process is re-initiated with the notification device 110 again electronically requesting the readiness status of each of the six non-continuous OBDII monitors. While the invention has been described in conjunction with two exemplary embodiments thereof, it will be obvious to those skilled in the art that other modifications may also be made to | <SOH> BACKGROUND OF THE INVENTION <EOH>The present invention relates to vehicle emissions testing, and, more particularly, to a device that notifies a vehicle operator that the vehicle is ready for an emissions inspection. Recognizing the adverse effects that vehicle emissions have on the environment, the 1990 Clean Air Act requires that communities in geographic regions having high levels of air pollution implement Inspection and Maintenance (“I/M”) programs for vehicles in the particular geographic regions. Such I/M programs are intended to improve air quality by periodically testing the evaporative and exhaust emissions control systems of vehicles in the community and ensuring their proper operation and maintenance. By ensuring that the evaporative and exhaust emissions control systems of vehicles are operational and properly maintained, air pollution resulting from vehicle emissions in the geographic region should be drastically reduced. I/M programs in the United States typically employ some method of “tailpipe” testing as the primary means of inspection. Although there are several variations of common tailpipe testing, the core function of tailpipe testing remains the same. First, a probe is attached to, or inserted into, the tailpipe of the vehicle being tested to collect exhaust as the engine of the vehicle is running. The collected exhaust is then introduced into a series of gas analyzers in order to determine its composition. Finally, a report of the amount of measured pollutants is generated. In 1992, the California Air Resources Board (CARB) proposed regulations for the monitoring and evaluation of a vehicle's emissions control system through the use of second-generation on-board diagnostics (“OBDII”). (See California Code of Regulations, Title 13, 1968.1—Malfunction and Diagnostic Systems Requirements—1994 and subsequent model year passenger cars, light-duty trucks, and medium-duty vehicles with feedback fuel control systems.) These regulations were later adopted by the United States Environmental Protection Agency. (See Environmental Protection Agency, 40 C.F.R. Part 86—Control of Air Pollution From New Motor Vehicles and New Motor Vehicle Engines; Regulations Requiring On-Board Diagnostic Systems on 1994 and Later Model Year Light-Duty Vehicles and Light-Duty Trucks.) As a result, OBDII systems were required to be phased in beginning in 1994, and by 1996, almost all light-duty, gasoline-powered motor vehicles in the United States were required to have OBDII systems. In general, through the use of OBDII systems, the emissions control system of a vehicle is constantly monitored, with a “check engine” light or Malfunction Indicator Light (MIL) on the dashboard of the vehicle being illuminated to inform the operator of a problem with the emissions control systems. The OBDII system is commonly interrogated as part of I/M programs to ensure it is functioning properly. Discussing now the more specific operational details, OBDII systems are designed to monitor certain emissions control systems, i.e., groupings of related vehicle emissions components, to ensure they are functioning properly. Each such emissions control system is evaluated by a “monitor,” which also may be referred to as an “OBDII monitor” or a “readiness monitor.” CARB designates eleven monitors that the OBDII system of a vehicle may be required to evaluate: TABLE A MONITOR TYPE Fuel Metering/Trim Continuous Misfire Continuous Comprehensive Continuous Component Air Conditioning Unsupported Catalyst Heater Unsupported Catalyst Non-continuous Oxygen Sensor Non-continuous Oxygen Sensor Heater Non-continuous Evaporative Emissions Non-continuous Control System Secondary Air Non-continuous Exhaust Gas Recirculation Non-continuous As indicated in Table A, the first three monitors are “continuous” in that evaluation of the particular emissions control system is ongoing at any time the vehicle engine is operating. For this reason, these three monitors are always reported by the OBDII system as being “ready,” meaning that the system has been evaluated. In this regard, it is important to recognize that a status of “ready” does not mean that the particular emissions control system is operating properly, but only that the system has been evaluated. If a particular vehicle emissions system has been evaluated, and a fault is found with the system, the check engine light or MIL will be illuminated. Referring still to Table A, although identified in the applicable regulations, the air conditioning and catalyst heater monitors are not included in most vehicles and are therefore reported by the OBDII system as “unsupported.” Finally, the remaining six monitors are characterized as “non-continuous” because if the vehicle supports them, functionality of the particular emissions control system can only be evaluated after the vehicle has been operating for a predetermined time period or until certain conditions are satisfied. Accordingly, a non-continuous monitor will be reported by the OBDII system as “not ready” until the predetermined time period has elapsed or the certain conditions have been satisfied. For example, assuming a non-continuous monitor is supported, the monitor will have a status of “not ready” when the vehicle is brand new (since the monitor has not yet had an opportunity to evaluate the emissions control system), if the battery has been disconnected for a period of time (such that computer memory is cleared), or if a technician performs specific operations on the OBDII system. After the vehicle has been operated until the predetermined time period has elapsed or the certain conditions have been satisfied, each monitor will evaluate its emissions control system, and the status of each monitor will then be reported as “ready.” The status continues to be reported as “ready” until reset by a technician or the battery of the vehicle is disconnected. For example, the catalyst monitor evaluates whether the catalyst is functioning properly. This is generally accomplished through the use of two oxygen sensors, one upstream of the catalyst and one downstream of the catalyst. On a properly operating vehicle, the engine will vary from operating slightly lean (excess oxygen) to slightly rich (excess fuel). A common three-way catalyst, a catalyst that reduces the levels of hydrocarbons, carbon monoxide, and oxides of nitrogen, captures and stores the excess oxygen in the exhaust during the slightly lean periods, and then uses that oxygen during the periods of slightly rich operation to oxidize the hydrocarbons to carbon dioxide and water and to oxidize the carbon monoxide to carbon dioxide. Therefore, if a catalyst is functioning properly, the oxygen sensor upstream of the catalyst should measure a fluctuation in the oxygen content in the exhaust, but the downstream oxygen sensor should measure a much lower fluctuation in the oxygen content in the exhaust (since the oxygen is being absorbed by the catalyst and then converted into other molecules before passing the downstream oxygen sensor). If, however, the upstream and downstream sensors measure the same fluctuation in the oxygen content in the exhaust gas, it is an indication that the catalyst is not storing the excess oxygen and is therefore probably not oxidizing the hydrocarbons and carbon monoxide. Accordingly, the OBDII system may activate the check engine light to notify the vehicle operator that there is a problem with this emissions control system. However, the catalyst functions properly only under specific conditions, and thus, the OBDII catalyst monitor often cannot immediately evaluate the catalyst after the OBDII memory is cleared and the catalyst monitor is reset to “not ready.” For instance, if the catalyst is cold, or if one of the oxygen sensors is not functioning properly, then the system cannot evaluate the catalyst function. Until the catalyst is in condition to be evaluated, the catalyst monitor will report a status of “not ready.” Once the appropriate conditions have been satisfied, the catalyst is evaluated, and the catalyst monitor is reported as “ready.” In the past, I/M programs have often included under-hood visual and functional inspections of emissions control components combined with tailpipe emissions tests to determine if the emissions control systems of a vehicle are functioning properly. However, in recent years, an increasing number of I/M programs have been inspecting 1996 and newer vehicles by using electronic interrogation of the OBDII system to determine if the emissions control systems of a vehicle are functioning properly. Such testing is described in detail in “Performing Onboard Diagnostic System Checks as Part of a Vehicle Inspection and Maintenance Program,” EPA 420-R-01015 (June 2001), a report that is incorporated herein in its entirety by this reference. However, if the battery of a vehicle is disconnected for a period of time, the OBDII system memory is cleared. If there was a fault previously identified by the OBDII system that caused the MIL to be illuminated, it will also be cleared. If the vehicle is tested in an I/M program via the OBDII system shortly after having the battery disconnected, the OBDII system may now appear not to have a problem because the OBDII system may not have had a chance to find the fault again before the I/M OBDII emissions inspection. Furthermore, I/M program regulations typically require service technicians to clear the OBDII memory after repairs are performed. This is done so that when the OBDII system of the vehicle is checked after the repair to determine if the problem has been appropriately remedied, it is clear if the monitor for the system that was repaired has run and checked the repaired system. Again, if a particular system has been evaluated, it will be reported as “ready.” If it has not been evaluated, it will be reported as “not ready.” Because unscrupulous vehicle operators, recognizing that there is a problem with an emissions control system because the MIL is illuminated, could attempt to conceal a known defect by disconnecting the battery to clear the OBDII system memory, I/M programs require a check of the readiness monitors to verify that the OBDII system has evaluated the emissions control systems. Because of the check for readiness, if the battery was disconnected just before the test to clear an illuminated MIL, various monitors will be reported as “not ready,” and thus, the vehicle will not be allowed to pass the I/M OBDII emissions inspection. Furthermore, it is possible that through normal operation, all of the monitors in a vehicle may not be set to “ready.” Therefore, the EPA has suggested in its guidance on performing I/M OBDII emissions inspections that vehicles with model years of 1996-2000 should be considered ready if two or fewer of the non-continuous monitors are “not ready.” For 2001 and newer vehicles, one non-continuous monitor may be reported as “not ready.” Furthermore, in a few states, three monitors are allowed to be “not ready,” and the vehicle is still considered ready for the OBDII I/M emissions inspection. As mentioned above, if a vehicle fails an I/M OBDII emissions inspection and is repaired, the OBDII memory will be cleared and monitors will be reset to “not ready.” Since the vehicle cannot pass an emissions inspection until only a few monitors of the OBDII system are reporting their status as “not ready,” the technician may instruct the vehicle operator to drive the vehicle for a period of time and then return so the technician can check to see if the vehicle is ready to be tested. Because the technician cannot tell the vehicle operator how long they should drive the vehicle to get it ready, and vehicle operators are not pleased to return for an inspection only to discover that too many monitors are still reporting their status as “not ready,” there is a need for a device that can communicate to and notify a vehicle operator that a vehicle is ready for an I/M OBDII emissions inspection. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention is a device that notifies a vehicle operator that the vehicle is ready for an I/M OBDII emissions inspection. In one exemplary embodiment, the notification device includes a housing that encloses a circuit board with a control logic responsible for the function and operation of the notification device. At one end of the housing, there is a connection port designed to mate with the Diagnostic Link Connector (DLC) of a vehicle, placing the control logic of the notification device in electrical communication with the OBDII system of the vehicle. At the other end of the housing, there are preferably two indicator lights, a first indicator light being illuminated to indicate that the vehicle is not ready for an I/M OBDII emissions inspection, and the second light being illuminated when the vehicle is ready for an I/M OBDII emissions inspection. In operation, the control logic of the notification device evaluates the status of a plurality of the respective monitors of the OBDII system. Based on such an evaluation, and specifically a count of the number of monitors reporting as “not ready,” the notification device will either illuminate the “not ready” light if the vehicle is not ready for an I/M OBDII emissions inspection, or the “ready” light if the vehicle is ready for an I/M OBDII emissions inspection. Additionally, the notification device may have a speaker to emit an audio signal, in lieu of or in addition to the visual indicator, when the OBDII system of the vehicle is ready for an I/M OBDII emissions inspection. As a further refinement, the notification device may also include two selector switches on a surface of the housing. The first selector switch allows an operator to indicate the number of readiness monitors of the OBDII system that will be allowed to be reported as “not ready,” while still allowing the device to report the vehicle as being ready to be tested. The second selector switch allows an operator to indicate whether the catalyst monitor must be reporting as “ready” in order for the notification device to report the vehicle as being ready to be tested. As yet a further refinement, the notification device may also include a third selector switch used to indicate how the notification device will notify the vehicle operator when the OBDII system of the vehicle is ready for an I/M OBDII emissions inspection. In this regard, the selector switch can be set to “audio,” and the notification device will emit an audio signal when the vehicle is ready for an I/M OBDII emissions inspection. Alternatively, the selector switch can be set to “visual,” and the notification device will illuminate the “not ready” light if the vehicle is not ready for an I/M OBDII emissions inspection. Once the vehicle is ready for an I/M OBDII emissions inspection, the notification device will then illuminate the “ready” light. If the selector switch is set to “both,” then both the audio and visual signaling techniques will be used when the vehicle is ready for an I/M OBDII emissions inspection. As yet a further refinement, the notification device may include six additional indicator lights, each of which corresponds to a particular non-continuous monitor of the OBDII system. When a monitor has been checked and is reporting as “ready” or “unsupported,” the corresponding indicator light is illuminated to notify the operator of the status of that particular monitor. | 20040414 | 20060314 | 20060209 | 63726.0 | G01M1700 | 1 | POPE, DARYL C | OBDII READINESS STATUS NOTIFICATION DEVICE | SMALL | 0 | ACCEPTED | G01M | 2,004 |
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10,824,471 | ACCEPTED | FLYBACK CONVERTER FOR PERFORMING A ZERO VOLATAGE SWITCH IN BOUNDARY MODE | The present invention is to provide a flyback converter by utilizing harmonic effect generated by a transformer thereof, after transferring electric energy in the transformer in a boundary mode, through cooperating with a simple control circuit to draw the charges stored in a main switch thereof out and enable the main switch to perform a zero voltage switch under a variety of loads in the boundary mode, which not only greatly reduces switch loss thereof, but also effectively limits an operating frequency of the main switch in a predetermined range to greatly decrease peak value of voltage caused by inductance leakage and have the advantages of high efficiency, high switching frequency and low noise without increasing the manufacturing cost. | 1. A flyback converter for performing a zero voltage switch in a boundary mode, comprising: a transformer including a primary winding and a secondary winding; a series circuit including at least one auxiliary capacitor and a switch at the primary side in series connected with the auxiliary capacitor, the series circuit being in parallel connected with the primary winding; a switch at the secondary side being in series connected with the secondary winding; a main switch being in series connected with one terminal of the series circuit adjacent to the auxiliary capacitor; and at least one driver circuit interconnected the main switch and the auxiliary capacitor for sensing voltage at a joining node of the main switch and the auxiliary capacitor, generating a driver signal, and sending the same to the switches at the primary and the secondary sides for switching them respectively, wherein when the switch at the secondary side is turned into a closed condition, the switch at the primary side is switched to a closed condition enabling the switch at the primary side to store the electric energy of the primary winding to the auxiliary capacitor; when the switch at the secondary side is turned from the closed condition into an opened condition, the closed condition of the switch at the primary side is maintained for a predetermined period of time enabling the auxiliary capacitor to charge the primary winding until the electric energy being charged into the transformer is sufficient to cause the main switch to perform a zero voltage switch. 2. The flyback converter of claim 1, further comprising a diode in parallel connected with the main switch. 3. The flyback converter of claim 2, further comprising an input voltage filter capacitor having a positive terminal coupled to one terminal of the primary winding and a negative terminal coupled to the main switch, wherein the positive and the negative terminals of the input voltage filter capacitor are coupled to the positive and negative terminals of an input voltage. 4. The flyback converter of claim 3, wherein one terminal of the switch at the primary side is coupled to a positive terminal of the input voltage filter capacitor and the other terminal thereof is coupled to the auxiliary capacitor. 5. The flyback converter of claim 4, wherein a positive terminal of the diode is coupled to a negative terminal of the input voltage filter capacitor and a negative terminal thereof is coupled to the auxiliary capacitor. 6. The flyback converter of claim 5, wherein the main switch is a metal-oxide-semiconductor field-effect transistor (MOSFET). 7. The flyback converter of claim 5, wherein the switch at the primary side is a metal-oxide-semiconductor field-effect transistor (MOSFET). 8. The flyback converter of claim 1, further comprising an output voltage filter capacitor having a negative terminal coupled to one terminal of the secondary winding and a positive terminal coupled to the switch at the secondary side wherein the positive and the negative terminals of the output voltage filter capacitor are coupled to the positive and negative terminals of an output voltage. 9. The flyback converter of claim 8, wherein the switch at the secondary side is a diode. | FIELD OF THE INVENTION The present invention relates to flyback converters and more particularly to a flyback converter for performing a zero voltage switch in a boundary mode. BACKGROUND OF THE INVENTION Conventionally, a converter capable of operating in a boundary mode may be a ringing choke converter (hereinafter abbreviated as RCC), FIG. 1 shows the circuit diagram of a standard RCC. As stated above, since the standard RCC operates in the boundary mode, when a transformer T1 of the RCC transfers its electric energy to a secondary winding thereof having an output voltage Vo, a primary winding of the transformer T1 has a voltage Vo·n where n is a ratio of the primary winding to the secondary winding. That is, a voltage VCE of a switch transistor Q1 is equal to a sum of an input voltage Vin and the voltage Vo·n of the primary winding (i.e., Vin+Vo·n). The electric energy is stored in a parasite capacitor of the circuit in a form of voltage. In the above-mentioned conventional RCC, when the electric energy stored in the transformer T1 is not sufficient to conduct a diode D1 being in series connection to the secondary winding of the RCC, the diode D1 is cut off and a harmonic is generated by the parasite capacitor and inductance of the circuit. After that, if the switch transistor Q1 is not switched again, the voltage VCE of the switch transistor Q1 oscillates as a sine wave centered on Vin having an amplitude equal to Vo·n. The sine wave shows an exponential decrease due to the effect of impedance in the circuit. FIG. 2 shows a waveform graph of the RCC operated in the boundary mode, wherein the dash lines shows the sine wave oscillation of the voltage VCE and the voltage VCE of the switch transistor Q1 has a minimum value of Vin−Vo·n. Thus, by appropriately designing a driver circuit of the switch transistor Q1 to drive the switch transistor Q1 when the voltage VCE of the switch transistor Q1 has a minimum value, switch loss of the switch transistor Q1 can be predicted through using the following equation. Cs · ( V CE ) 2 2 · fo where CS is an equivalent stray capacitance of the circuit, and fo is an operating frequency of the switch transistor Q1. It is clear that the switch loss of the switch transistor Q1 will be reduced significantly as the voltage VCE of the switch transistor Q1 drops. However, since the RCC operates in the boundary mode, the operating frequency fo of the switch transistor Q1 will increase as the input voltage Vin increases and the output load decreases. Thus, according to the above equation for calculating the switch loss, the switch transistor Q1 will still generate a substantial switch loss. Hence, when the operating frequency fo increases, the switch loss will increase significantly. In view of the above, in order to lower the switch loss to zero for substantially eliminating the problem occurred in a high frequency operating state when the typical RCC operates in the boundary mode, the following actions should be taken by the designers and manufacturers of converters in designing their control circuits: (1) Parallelly coupling a diode to the collector and the emitter of the switch transistor Q1 of the RCC or replacing the switch transistor Q1 with a transistor having a parasite diode (e.g., metal-oxide-semiconductor field-effect transistor, abbreviated as MOSFET) such that the voltage VCE of the switch transistor Q1 can be clamped at a level by the diode or the parasite diode for performing a zero voltage switch after the harmonic has reached a zero voltage level. (2) Designing the circuitry of the RCC such that the amplitude of the above sine wave can be equal to Vin and the feedback voltage of the primary winding become larger than Vin. As a result, the minimum value of voltage VCE of the switch transistor Q1 is zero, and a switch is made possible when the zero voltage level is reached. However, the cost for taking the above actions is that a transistor capable of operating in a high voltage is required since there is 2·Vin voltage drop in the switch transistor Q1. Moreover, since the cost and impedance of the transistor are relatively high, taking the above actions will unfortunately not only increase the manufacturing cost of RCC, but also increase the conduction loss of the transistor. As an end, the total performance is low. Hence, it is desirable among designers and manufacturers of the art to devise a switch transistor Q1 of converter capable of performing a zero voltage switch under a variety of loads in a boundary mode without increasing the manufacturing cost and the conduction loss in order to overcome the above drawbacks of the prior art. SUMMARY OF THE INVENTION A primary object of the present invention is to provide a flyback converter for performing a zero voltage switch in a boundary mode. The flyback converter comprises a transformer including a primary winding in parallel connected with a series circuit including at least one capacitor and a switch at the primary side, and a secondary winding in series connected with a switch (or a diode) at the secondary side. When the switch at the secondary side is activated into a closed condition, the switch at the primary side is also activated into a closed condition for storing the electric energy in the primary winding to the capacitor. Then, when the switch at the secondary side is activated from the closed condition into an opened condition, the switch at the primary side remains in the closed condition for a predetermined period of time enabling the capacitor to charge the primary winding until the electric energy being charged to the transformer is sufficient to cause a main switch in series connected with the primary winding to perform a zero voltage switch, and the switch at the primary side is then activated from the closed condition into an opened condition to finish the zero voltage switch. By utilizing the present invention, the above drawback of the prior ringing choke converter, such as the higher of the operating frequency the higher of the switch loss of the switch transistor, can be overcome. One object of the present invention is to utilize the harmonic effect generated by the transformer, after the electric energy therein being transferred in the boundary mode, through cooperating with a simple control circuit, to draw the charges stored in the main switch out, enabling the main switch to perform a zero voltage switch under a variety of loads in a boundary mode and greatly reduce the switch loss thereof. Another object of the present invention is to limit an operating frequency of the main switch in a predetermined range under a variety of loads in a boundary mode in order to greatly decrease peak value of voltage caused by inductance leakage and enable the flyback converter to have the advantages of high efficiency, high switching frequency and low noise under the condition without increasing the manufacturing cost. The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram of a conventional RCC; FIG. 2 is a waveform graph of the voltage VCE of the switch transistor Q1 of the RCC in FIG. 1 operated in a boundary mode; FIG. 3 is a circuit diagram of a flyback converter according to the invention; FIG. 4 is a waveform graph at four periods of time versus the voltage VSW1 of the switch SW1 when the flyback converter operates in a boundary mode; FIGS. 5(a), 5(b), 5(c), and 5(d) are equivalent circuit diagrams when the flyback converter operates in four periods of time; FIG. 6 is a circuit diagram of a preferred embodiment of the invention; and FIG. 7 is a waveform graph showing voltage values of the components shown in the preferred embodiment of the invention in FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 3, there is shown a circuit diagram of a flyback converter operated in a boundary mode according to a preferred embodiment of the invention. The converter comprises a transformer T1, an input voltage filter capacitor Cin, an auxiliary capacitor Ca, a driver circuit DR, three switches SW1, SW2, and SW3, and an output voltage filter capacitor Co. Each component will be described in detail below. The transformer T1 is adapted to store electric energy and transfer the same. The transformer T1 comprises a primary winding Np and a secondary winding Ns in which the turn ratio of Np/Ns is n. The inductances of the primary winding Np and the secondary winding Ns are respectively Lp and Ls. The winding directions of the primary winding Np and the secondary winding Ns are marked as shown in FIG. 3. One terminal of the primary winding Np of the transformer T1 is coupled to a positive terminal of the input voltage filter capacitor Cin and the other terminal thereof is coupled to the main switch SW1. The positive and negative terminals of the input voltage filter capacitor Cin are coupled to the positive and negative terminals of the input voltage Vin respectively. One terminal of the switch SW2 at the primary side is coupled to the positive terminal of the input voltage filter capacitor Cin and the other terminal thereof is coupled to the auxiliary capacitor Ca. The other terminal of the auxiliary capacitor Ca is coupled to one terminal of the main switch SW1. The other terminal of the main switch SW1 is coupled to the negative terminal of the input voltage filter capacitor Cin. As such, the input voltage filter capacitor Cin is able to supply a stable input voltage to the transformer T1. Moreover, a diode DSW1 is in parallel connected with the main switch SW1. The positive terminal of the diode DSW1 is coupled to the negative terminal of the input voltage filter capacitor Cin and the negative terminal thereof is coupled to the auxiliary capacitor Ca. The driver circuit DR is coupled to a joining node of the main switch SW1 and the auxiliary capacitor Ca such that it is possible of sensing voltage at the joining node for determining whether the switch SW2 at the primary side should be cut off. In the embodiment, one terminal of the secondary winding Ns is coupled to the negative terminal of the output voltage filter capacitor Co and the other terminal thereof is coupled to a positive terminal of the switch SW3 at the secondary side. The negative terminal of the switch SW3 at the secondary side is coupled to the positive terminal of the output voltage filter capacitor Co such that the output voltage filter capacitor Co is able to supply a stable DC output voltage Vo to a load connected to the output. When the flyback converter operates in a boundary mode, the transformer T1 may transfer the electric energy stored therein to the secondary winding Ns for generating an output voltage Vo. At this moment, the voltage of the secondary winding is equal to Vo·n and the electric energy is stored in both the auxiliary capacitor Ca and the parasite capacitor of the circuit. When the electric energy stored in the transformer T1 is not sufficient to maintain the switch SW3 at the secondary side in a closed condition, the switch SW3 at the secondary side changes its status from the closed condition to a opened condition. At the same time, the switch SW2 at the primary side is still maintained in a closed condition, such that a harmonic is generated by parasite capacitor, the auxiliary capacitor Ca and the secondary winding Ns and the electric energy originally stored in the auxiliary capacitor Ca and the parasite capacitor will charge the primary winding Np of the transformer T1. When the electric energy being charged in the primary winding Np is sufficiently high to cause the main switch SW1 (i.e., main electronic switch) to perform a zero voltage switch, the switch SW2 at the primary side is then turned into an opened condition and the electric energy stored in the primary winding Np begins to feed back. At this moment, since the switch SW2 at the primary side is in the opened condition, the electric energy being fed back is completely stored in the parasite capacitance of the circuit. And, the harmonic behavior significantly increases the voltage variation of the parasite capacitor and increases the voltage of the main switch SW1 to a value larger than Vf in order to conduct the diode DSW1 and enable the main switch SW1 to perform a zero voltage switch when its voltage is equal to zero. If the diode DSW1 doen't exist, the harmonic behavior will continue to oscillate along its center Vin as indicated by dash lines of VSW1 in FIG. 4. By comparing the circuitry of the flyback converter of the invention with that of the conventional RCC, it is clearly seen that after the switch SW3 at the secondary side turns to be in the opened condition, the harmonic generated by the primary winding Np of the transformer T1 will slow the L-C harmonic due to the existence of the auxiliary capacitor Ca. Therefore, during the harmonic activation period, the main switch SW1 won't be activated. Thus, the operating frequency of the flyback converter of the invention is limited by a maximum value, which causes the operating frequency of the flyback converter to increase to a value less than that of the conventional RCC when the load decreases. Referring to FIG. 4, there is shown a waveform graph when the flyback converter operates in a boundary mode. As shown, DR1 is a driver signal sent from the driver circuit DR to the main switch SW1. VSW1 is the voltage measured across both terminals of the main switch SW1. DR2 is a driver signal sent from the driver circuit DR to the switch SW2 at the primary side. For the convenience of discussing operation of the flyback converter of the invention, the waveforms of the driver signals DR1 and DR2 and VSW1 of the main switch SW1 in a cycle of the main switch SW1 are divided into four periods of time. The operations of equivalent circuits of the flyback converter of the invention in respective periods of time are shown in FIGS. 5(a) to 5(d) and will be further discussed as follows: (1) Period of Time from t0 to t1: Referring to the equivalent circuit shown in FIG. 5(a), the parasite capacitor Cs existing in the transformer T1 and the switches SW1, SW2, and SW3 is equivalently labeled on both terminals of the primary winding Np of the transformer T1. Also, in the equivalent circuit, the region enclosed by the solid line means the operating section of the circuit and the region enclosed by the dash line means the non-operating section of the circuit. Before t0, both the switch SW2 at the primary side and the switch SW3 at the secondary side are in closed condition, the transformer T1 is in a status of transferring electric energy, and the voltage of the auxiliary capacitor Ca and the parasite capacitor Cs is equal to Vo n , a voltage fed back from output voltage Vo to the primary winding Np. When t=t0, the switch SW3 at the secondary side will turn to be in an opened condition, since the electric energy stored in the transformer T1 is not sufficient to maintain the switch SW3 at the secondary side in the closed condition. In a period of time from t0 to t1, a harmonic is generated by the auxiliary capacitor Ca, the parasite capacitor Cs, and inductance Lp of the primary winding Np of the transformer T1, and the electric energy stored in the auxiliary capacitor Ca and the parasite capacitor Cs will be transferred to the inductance Lp of the primary winding Np. (2) Period of time from t1 to t2: Referring to the equivalent circuit shown in FIG. 5(b), this period of time is critical to zero voltage switch of the main switch SW1. In time t1, the driver circuit DR generates a driver signal DR2 and sends the same to the switch SW2 at the primary side for turning the switch SW2 at the primary into an opened condition in response to sensing that the voltage across both terminals of the primary winding Np (i.e., the voltage at both terminals of the auxiliary capacitor Ca) has dropped below a predetermined level, and turning the auxiliary capacitor Ca into an open loop. Only the parasite capacitor Cs can continue to generate harmonic through in cooperation with the inductance Lp of the primary winding Np. Before t1, all the electric energy stored in the auxiliary capacitor Ca and the parasite capacitor Cs is substantially transferred to the inductance Lp of the primary winding Np. Therefore, when t=t1, the electric energy stored in the inductance Lp of the primary winding Np is transferred back to the capacitors. At this moment, since the auxiliary capacitor Ca is absent from the capacitors of the harmonic elements, the electric energy stored in the inductance Lp of the primary winding Np will cause the voltage across the parasite capacitor Cs to increase rapidly. If the voltage variation on the parasite capacitor Cs is called as V1, then according to the following equation: 1 2 · ( Ca + Cs ) · ( Vo n ) 2 -> 1 2 · Lp · i P 2 -> 1 2 · Cs · V1 2 , the voltage variation V1 across the parasite capacitor Cs is equal to V1 = Vo n · 1 + Ca Cs . Beside, since the critical moment for performing zero voltage switch is at the time when V1 larger than Vin, i.e.: Vo n · 1 + Ca Cs > Vin Thus, if the selected auxiliary capacitor Ca has a sufficient capacitance, the voltage of the main switch SW1 will decrease to zero due to harmonic. (3) Period of time from t2 to t3: Referring to the equivalent circuit shown in FIG. 5(c), when t=t2, the voltage of the main switch SW1 will drop below Vf and cause the diode DSW1 in parallel connected with the main switch SW1 to be conducted. The voltage of the main switch SW1 is then clamped at −Vf, at this moment the main switch SW1 is preparing to proceed with the action of zero voltage switch. Thus, when the driver circuit DR generates a driver signal DR1 and sends the same to the main switch SW1, the main switch SW1 turns into a closed condition and completes the action of zero voltage switch. Moreover, in the period of time from t2 to t3, the transformer T1 begins to store the electric energy. (4) Period of time from t3 to t0: Referring to the equivalent circuit shown in FIG. 5(d), when t=t3, the driver circuit DR generate a driver signal DR1 and a driver signal DR2 and send the same to the main switch SW1 and the switch SW2 at the primary side respectively for turnling the main switch SW1 into an opened condition and turning the switch SW2 at the primary side into a closed condition. In the period of time from t3 to t0, the transformer T1 begins to transfer the electric energy stored therein. When t=t0, the main switch SW1 is in the opened condition and the transformer T1 thus begins to transfer the stored electric energy to both the auxiliary capacitor Ca and the parasite capacitor Cs, the voltage of the transformer T1 thus changes its polarity for turning the switch SW3 at the secondary side into a closed condition. At this moment, since the driver circuit DR senses that the voltage VNP of the primary winding Np of the transformer T1 has changed from negative to positive, the driver circuit DR will generate a driver signal DR2 and send the same to the switch SW2 at the primary side to turn the switch SW2 at the primary side into a closed condition. The voltage of the auxiliary capacitor Ca and the parasite capacitor Cs is then equal to Vo/n, which is a voltage fed back from the output voltage Vo to the transformer T1. Referring to FIG. 6, there is shown a circuit diagram of a preferred embodiment of the invention. In the embodiment, each of the main switch SW1 and the switch SW2 at the primary side mentioned in the invention can be replaced by metal-oxide-semiconductor field-effect transistors (MOSFETs) Q1 and Q2 respectively. Further, the switch SW3 at the secondary side mentioned in the invention can be replaced by a diode D1. The embodiment is then measured to obtain a waveform graph showing voltage values of the components of the circuit in the embodiment as shown in FIG. 7, wherein it is clearly seen that the voltage Vds1 of the main transistor Q1 slowly drops from a maximum value to a value about equal to the input voltage Vin (in the embodiment, the input voltage Vin is about equal to 350V). However, when the transistor Q2 at the primary side is turned into an opened condition, i.e. when the driver signal Vgs2 changes from high to low, the voltage Vds1 of the main transistor Q1 will rapidly drop to a value about equal to 0V. At this moment, the driver signal Vgs1 quickly changes from low to high. As a result, the main transistor Q1 completes the action of zero voltage switch. In view of the above, the flyback converter of the invention utilizes the harmonic effect generated by the transformer, after the electric energy therein being transferred in the boundary mode, through cooperating with a simple control circuit to draw the charges stored in the main switch out and enable the main switch to perform a zero voltage switch under a variety of loads in a boundary mode, which not only greatly reduces the switch loss thereof, but also effectively limits an operating frequency of the main switch in a predetermined range to greatly decrease the peak value of voltage caused by inductance leakage and enable the flyback converter to have the advantages of high efficiency, high switching frequency and low noise under the condition without increasing the manufacturing cost. While the invention has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>Conventionally, a converter capable of operating in a boundary mode may be a ringing choke converter (hereinafter abbreviated as RCC), FIG. 1 shows the circuit diagram of a standard RCC. As stated above, since the standard RCC operates in the boundary mode, when a transformer T 1 of the RCC transfers its electric energy to a secondary winding thereof having an output voltage Vo, a primary winding of the transformer T 1 has a voltage Vo·n where n is a ratio of the primary winding to the secondary winding. That is, a voltage V CE of a switch transistor Q 1 is equal to a sum of an input voltage Vin and the voltage Vo·n of the primary winding (i.e., Vin+Vo·n). The electric energy is stored in a parasite capacitor of the circuit in a form of voltage. In the above-mentioned conventional RCC, when the electric energy stored in the transformer T 1 is not sufficient to conduct a diode D 1 being in series connection to the secondary winding of the RCC, the diode D 1 is cut off and a harmonic is generated by the parasite capacitor and inductance of the circuit. After that, if the switch transistor Q 1 is not switched again, the voltage V CE of the switch transistor Q 1 oscillates as a sine wave centered on Vin having an amplitude equal to Vo·n. The sine wave shows an exponential decrease due to the effect of impedance in the circuit. FIG. 2 shows a waveform graph of the RCC operated in the boundary mode, wherein the dash lines shows the sine wave oscillation of the voltage V CE and the voltage V CE of the switch transistor Q 1 has a minimum value of Vin−Vo·n. Thus, by appropriately designing a driver circuit of the switch transistor Q 1 to drive the switch transistor Q 1 when the voltage V CE of the switch transistor Q 1 has a minimum value, switch loss of the switch transistor Q 1 can be predicted through using the following equation. Cs · ( V CE ) 2 2 · fo where C S is an equivalent stray capacitance of the circuit, and f o is an operating frequency of the switch transistor Q 1 . It is clear that the switch loss of the switch transistor Q 1 will be reduced significantly as the voltage V CE of the switch transistor Q 1 drops. However, since the RCC operates in the boundary mode, the operating frequency f o of the switch transistor Q 1 will increase as the input voltage Vin increases and the output load decreases. Thus, according to the above equation for calculating the switch loss, the switch transistor Q 1 will still generate a substantial switch loss. Hence, when the operating frequency f o increases, the switch loss will increase significantly. In view of the above, in order to lower the switch loss to zero for substantially eliminating the problem occurred in a high frequency operating state when the typical RCC operates in the boundary mode, the following actions should be taken by the designers and manufacturers of converters in designing their control circuits: (1) Parallelly coupling a diode to the collector and the emitter of the switch transistor Q 1 of the RCC or replacing the switch transistor Q 1 with a transistor having a parasite diode (e.g., metal-oxide-semiconductor field-effect transistor, abbreviated as MOSFET) such that the voltage V CE of the switch transistor Q 1 can be clamped at a level by the diode or the parasite diode for performing a zero voltage switch after the harmonic has reached a zero voltage level. (2) Designing the circuitry of the RCC such that the amplitude of the above sine wave can be equal to Vin and the feedback voltage of the primary winding become larger than Vin. As a result, the minimum value of voltage V CE of the switch transistor Q 1 is zero, and a switch is made possible when the zero voltage level is reached. However, the cost for taking the above actions is that a transistor capable of operating in a high voltage is required since there is 2·Vin voltage drop in the switch transistor Q 1 . Moreover, since the cost and impedance of the transistor are relatively high, taking the above actions will unfortunately not only increase the manufacturing cost of RCC, but also increase the conduction loss of the transistor. As an end, the total performance is low. Hence, it is desirable among designers and manufacturers of the art to devise a switch transistor Q 1 of converter capable of performing a zero voltage switch under a variety of loads in a boundary mode without increasing the manufacturing cost and the conduction loss in order to overcome the above drawbacks of the prior art. | <SOH> SUMMARY OF THE INVENTION <EOH>A primary object of the present invention is to provide a flyback converter for performing a zero voltage switch in a boundary mode. The flyback converter comprises a transformer including a primary winding in parallel connected with a series circuit including at least one capacitor and a switch at the primary side, and a secondary winding in series connected with a switch (or a diode) at the secondary side. When the switch at the secondary side is activated into a closed condition, the switch at the primary side is also activated into a closed condition for storing the electric energy in the primary winding to the capacitor. Then, when the switch at the secondary side is activated from the closed condition into an opened condition, the switch at the primary side remains in the closed condition for a predetermined period of time enabling the capacitor to charge the primary winding until the electric energy being charged to the transformer is sufficient to cause a main switch in series connected with the primary winding to perform a zero voltage switch, and the switch at the primary side is then activated from the closed condition into an opened condition to finish the zero voltage switch. By utilizing the present invention, the above drawback of the prior ringing choke converter, such as the higher of the operating frequency the higher of the switch loss of the switch transistor, can be overcome. One object of the present invention is to utilize the harmonic effect generated by the transformer, after the electric energy therein being transferred in the boundary mode, through cooperating with a simple control circuit, to draw the charges stored in the main switch out, enabling the main switch to perform a zero voltage switch under a variety of loads in a boundary mode and greatly reduce the switch loss thereof. Another object of the present invention is to limit an operating frequency of the main switch in a predetermined range under a variety of loads in a boundary mode in order to greatly decrease peak value of voltage caused by inductance leakage and enable the flyback converter to have the advantages of high efficiency, high switching frequency and low noise under the condition without increasing the manufacturing cost. The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings. | 20040415 | 20050927 | 20050825 | 62401.0 | 1 | BERHANE, ADOLF D | FLYBACK CONVERTER FOR PERFORMING A ZERO VOLATAGE SWITCH IN BOUNDARY MODE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,824,493 | ACCEPTED | Keyboard video mouse switch and the method thereof | A plurality of local and remote computers share a plurality of local manipulating devices, and the connection agreements of the computers and the manipulating devices are different. First electrical signals from these manipulating devices are received, and each of the first electrical signals complies with the connection agreement of its source manipulating device. Each first electrical signal is then converted to a standard packet. The paths of these standard packets are routed between the manipulating devices and the computers. Afterwards, each standard packet is converted to a second electrical signal which complies with the connection agreement of its destination computer. | 1. A keyboard video mouse (KVM) switch for a plurality of computers to share a plurality of manipulating devices with different connection agreements, the KVM switch comprising: a plurality of first interfaces connected to the manipulating device to receive a plurality of first electrical signals, where each of the electrical signals complies with the connection agreement of its source manipulating device and each of the first interfaces has a first converting device to convert the first electrical signals into a standard packet; a switch device, which arranges the routing of the standard packet between the manipulating devices and the computers according to a path selection setting; and a plurality of second interfaces connected to the computers, where each of the second interfaces has a second converting device to convert the standard packet received by the switch device into a second electrical signal complying with the connection agreement of the connected computer. 2. The KVM switch of claim 1, wherein each of the electrical signals is selected from the group comprising a keyboard signal and a mouse signal. 3. The KVM switch of claim 1, when the KVM switch allows a plurality of local and remote computers to share a plurality of local manipulating devices, further comprising: a packet encoding device, which generates according to the standard packet at least one network packet with a plurality of data sections correspondingly storing the standard packets of the first interfaces; a network device, which establishes communications with the network device of another KVM switch using a network protocol for transmitting/receiving the network packet to/from another KVM switch; and a packet decoding device, which decodes the network packet transmitted from another KVM switch to obtain at least one remote standard packet. 4. The KVM switch of claim 3, wherein the network packet further has a network overhead section. 5. The KVM switch of claim 3, wherein the packet encoding device contains a CPU. 6. The KVM switch of claim 3, wherein the packet decoding device contains a CPU. 7. The KVM switch of claim 3, wherein the network device contains: a network interface chip (NIC), which connects to the packet encoding device and the packet decoding device; and a network switch, which has a first port, a second port, and a third port, where the first port connects to the NIC and one of the second port and the third port connects to another KVM switch. 8. The KVM switch of claim 7, wherein the network device further contains a 2-way switch connected to the second port for selecting between an Ethernet and another KVM switch. 9. The KVM switch of claim 1, wherein the first interfaces contain a plurality of universal asynchronous receivers/transmitters (UART's), a half-duplex communication processor, and a CPU. 10. The KVM switch of claim 1, wherein the second interfaces contain a plurality of universal asynchronous receivers/transmitters (UART's), a half-duplex communication processor, and a CPU. 11. The KVM switch of claim 1, wherein the switch device contains a CPU. 12. A computer switching method for a plurality of computers to share a plurality of manipulating devices with different connection agreements, the method comprising the steps of: receiving first electrical signals of the manipulating devices, each of the first electrical signals complying with the connection agreement of its source manipulating device; converting each of the first electrical signals into a standard packet; routing the standard packets between the manipulating devices and the computers; and converting each of the standard packets into a second electrical signal complying with the connection agreement of the computer of its path destination. 13. The method of claim 12, wherein each of the first electrical signals is selected from the group comprising a keyboard signal and a mouse signal. 14. The method of claim 12, wherein each of the first electrical signals is converted to the standard packet using a CPU. 15. The method of claim 12, wherein each of the standard packets is converted to the second electrical signal using a CPU. 16. The method of claim 12, wherein the paths of the standard packets are switched by a CPU according to a path selection setting. 17. The method of claim 12, when a plurality of local and remote computers shares a plurality of local manipulating devices, further comprising the steps of: distributing the standard packets, wherein the standard packets are transmitted to the corresponding local computers when the path destinations of the standard packets are the local computers whereas at least one network packet with a plurality of data sections correspondingly storing the standard packets is generated according to the standard packets when the path destinations thereof are the remote computers; establishing communications among the KVM switches using a network protocol for transmitting/receiving the network packet to/from another KVM switch; decoding the network packet transmitted from another KVM switch to obtain at least one remote standard packet; and converting the remote standard packet into the second electrical signal complying with the connection agreement of the local computer of its path destination. 18. The method of claim 17, wherein the network packet has a network overhead section. 19. The method of claim 17, wherein the standard packets are encoded in a single network packet when the path destinations of the standard packets are the remote computers connected to a same remote KVM switch. 20. The method of claim 17, wherein the communications among the KVM switches are established using a network interface chip (NIC) and a network switch configured for each of the KVM switches. 21. The method of claim 17, wherein the network packet is encoded and decoded using a CPU. | BACKGROUND OF THE INVENTION 1. Field of Invention The invention relates to a switch device and, in particular, to a KVM switch for multiple chaining and with high compatibility and the method thereof. 2. Related Art With the rapid development in information technology, computers and their peripherals become very popular. Computer users often use the mouse and keyboard to control the computers. Through the monitors or speakers, the computer users can monitor the state of the computers. Sometimes a user may have more than one computer to process different types of things. Traditionally, each computer is equipped with one set of input/output (IO) peripheral devices, including the keyboard, mouse, monitor, and speakers. However, this is a waste of money and space if one has several computers. On the other hand, large system businesses or enterprise internal networks often involve tens to thousands servers. Each server needs a monitor, a keyboard and a mouse to for management. In practice, one rarely needs to manipulate these devices. Most of the time, the servers do not need to be controlled by the manager. In this situation, it is totally unnecessary, costly, and wasting the space to have a set of IO peripheral devices for each server. Therefore, a keyboard video mouse (KVM) switch is proposed to use at least one set of operation device to manage several computers. Using the KVM switch does not only solve the cost problem, it simultaneously solves the problems of equipment and space. It may also conquer the compatibility problem among different interfaces. However, due to the hardware design and cost restriction of an individual KVM switch, the number of manipulating devices and computers it can accommodate is limited. On the other hand, it is not easy to connect conventional KVM switches together. When several manipulating devices simultaneously access multiple computers, the connection agreements among the manipulating devices and computers are often different. The commonly used connection agreements include the universal serial bus (USB) interface, the serial port (COM) interface, or the personal system/2 (PS/2) interface. The different connection agreements will reduce the compatibility of the KVM switches and the signal exchange efficiency among them. For example, when the connection agreement of the keyboard is the USB interface while that of the computer is the PS/2 interface, the conventional KVM switch usually converts the electrical signal to/from the keyboard to be PS/2 compatible. Nevertheless, such a method is not suitable for multiple chaining KVM switches. If they need to transmit electrical signals in different connection agreements, their circuits have to be able to understand various connection agreements. This does not only increase the design difficulty, the compatibility is still an issue that serious reduce its efficiency. The above-mentioned drawbacks result in a lot of inconvenience in practical uses. For large system businesses or the internal networks of mid-size enterprises, in particular, if the KVM switches cannot simultaneously support a large number of manipulating devices and computers, they do not only increase the costs for constructing and maintaining the system but also reduce the communication efficiency of the whole network. SUMMARY OF THE INVENTION An objective of the invention is to provide a KVM switch to improve the compatibility when there are different connection agreements. It further enables multiple chaining of KVM switches and thus allows connections to more manipulating device and computers. The invention also reduces the design difficulty. Another objective of the invention is to provide a computer switching method to improve the data exchange efficiency, compatibility, and extensibility of the KVM switches. The connected KVM switches can thus rapidly exchange data. Pursuant to the above objectives, this specification discloses a KVM switch and the method thereof. A plurality of local and remote computers share a plurality of local manipulating devices using a plurality of KVM switches, where the connection agreements of the computers and the manipulating devices are different. A plurality of first electrical signals of the manipulating devices are received, where each of the first electrical signals complies with the connection agreement of the source manipulating device. Each of he first electrical signals is converted into a standard packet. The paths of the standard packets are routed between the manipulating devices and the computers. Afterwards, each of the standard packets is converted into a second electrical signal that complies with the connection agreement of the destination computer. The disclosed KVM switch contains at least a plurality of first interfaces, a switch device, and a plurality of second interfaces. The first interfaces are connected to the manipulating devices to receive the first electrical signals, each of which complies with the connection agreement of the source manipulating device. Each first interface has a first converting device to convert the first electrical signal into a standard packet. The switch device determines the paths of the standard packets between the manipulating devices and the computers according to a path selection setting. The second interfaces are connected to the computers. Each second interface has a second converting device to convert the standard packet received from the switch device into a second electrical signal that complies with the connection agreement of the connected computer. According to a preferred embodiment of the invention, the switch device contains a central processing unit (CPU). Each of the electrical signals is selected from a keyboard signal and a mouse signal. The first interfaces contain several universal asynchronous receivers/transmitters (UART's), a half-duplex communication processor, and a CPU. The second interfaces also contain several UART's, a half-duplex communication processor, and a CPU. According to another embodiment of the invention, when the KVM switch provides a plurality of local and remote computers to share a plurality of local manipulating devices, the KVM switch further contains a packet encoding device, a network device, and a packet decoding device. The packet encoding device generates at least one network packet that contains a plurality of data sections correspondingly storing the standard packets of the first interfaces according to the standard packet. The network device communicates with another KVM switch using a network protocol in order to transmit network packets and to receive network packets from another KVM switch. The packet decoding device obtains at least one remote standard packet from the network packet transmitted by another KVM switch. According to the preferred embodiment, the network packet has a network overhead section. When the path destinations of the standard packets are the remote computers connected to the same remote KVM switch, the standard packets are encoded into a single network packet. The packet encoding device contains a CPU; the packet decoding device also contains a CPU. They may share the same CPU for both encoding and decoding. The network device contains a network interface chip (NIC) and a network switch. The NIC connects to the packet encoding device and the packet decoding device. The network switch has a first port, a second port, and a third port. The first port connects to the NIC. One of the second and third ports is for the connection of another KVM switch. The network device further contains a two-way switch connected to the second port for switching between the Ethernet and another KVM switch. BRIEF DESCRIPTION OF THE DRAWINGS The invention will become more fully understood from the detailed description given hereinbelow illustration only, and thus are not limitative of the present invention, and wherein: FIG. 1 is a schematic view of a preferred embodiment of the invention; FIG. 2 is a schematic view of FIG. 1 implemented in practice; FIG. 3 is a schematic view of the standard packet in FIG. 2; FIG. 4 is a schematic view of another embodiment of the invention; FIG. 5 is a schematic view of FIG. 4 implemented in practice; and FIG. 6 is a schematic view of the network packet in FIG. 5. DETAILED DESCRIPTION OF THE INVENTION For demonstration purposes, we draw only one first interface 114 and one second interface 112 in FIG. 1. The keyboard video mouse (KVM) switch 100 uses several first interfaces 114 (such as the USB, COM, PS/2, infrared, Bluetooth, or other wired and wireless interfaces) to connect to several local manipulating devices 154 (such as keyboards and mice) for electrical signal communications. In this case, the electrical signals comply with the connection agreement of the source local manipulating devices 154. The first interface 114 has a first converting device 164 for converting the electrical signal into a standard packet to be fed into a switch device 120 for routing. The switch device 120 (e.g. a switch chip, programmable chip or CPU) transmits the standard packet to the second interface 112 of its destination, and thus to the local computer 152 of its destination, according to a path selection setting. Several second interfaces 112 (such as the USB, COM, PS/2, infrared, Bluetooth, or other wired and wireless interfaces) are connected with several local computers 152. The second interface has a second converting device 162 for converting the standard packet into an electrical signal that complies with the connection agreement of the local computer 152 of its destination. Simply speaking, when an electrical signal is transmitted from the local manipulating device 154 to the first interface 114, it is first converted by the first converting device 164 into a standard packet. After being routed by the switch device 120, the standard packet is sent to the second interface 112 of its destination. The second converting device 162 then converts the standard packet into an electrical signal for the local computer 152. The standard packet transmitted by the KVM switch 100 complies with a predetermined or manufacturer defined connection agreement or format. The electrical signals transmitted at the first interface 114 and the second interface 112 comply with the connection agreements of the local manipulating devices 154 and the local computers 152 they connect to. The two interfaces 112, 114 convert electrical signals of different connection agreements into the standard packet of the same connection agreement. Within this structure, aside from the two interfaces 112, 114, one does not need to worry about the compatibility issue in the circuit design of other parts of the KVM switch 100. Therefore, the invention not only increases the data exchange efficiency and compatibility, but also reduces the design complexity and product costs. In FIG. 2, several second interfaces 112 connect to several local computers 152 via several computer connection ports 212. The connection agreement of each of the computer connection ports 212 is the same as that of the connected local computer 152. Several first interfaces 114 connect to several local manipulating devices 154 via several manipulating device connection ports 214. The connection agreement of each of the manipulating device connection ports 214 is the same as that of the connected local manipulating device 154. For demonstration purposes, we draw only one manipulating device connection port 214 and computer connection port 212 in FIG. 2. The electrical signals between the local computer 152 and the KVM switch 200 are transmitted using a set of universal asynchronous receivers/transmitters (UART's) and half-duplex communication processor 216. The electrical signals between the local manipulating devices 154 and the KVM switch 200 are also transmitted using the same set of universal asynchronous receivers/transmitters (UART's) and half-duplex communication processor 216. The KVM switch 200 in the preferred embodiment can simultaneously connect to 32 local computers 152 and four local manipulating devices 154. That is, the KVM switch 200 has 32 computer connection ports 112 and 4 manipulating device connection ports 114. Therefore, it requires four 9-port UART's and one half-duplex communication processor for electrical signal transmissions. The half-duplex communication processor can be replaced by a more expensive full-duplex communication processor or some other suitable processor. The manipulating device connection port 214 is the first converting device 164 while the computer connection port 212 is the second converting device 162. The CPU of them processes conversions between electrical signals and standard packet that have different connection agreements. The standard packet complies with the predetermined connection agreement, such as the USB connection agreement, or manufacturer defined format. This unifies the connection agreement used in the KVM switch 200. The data transmission speed and efficiency can also be increased through appropriate designs. Moreover, the preferred embodiment provides a first CPU 260 and a dual-port memory 270 in order to quickly process data exchanges between the manipulating device connection port 214, the computer connection port 212 and the second CPU 220. All the data from the manipulating device connection port 214 and the computer connection port 212 are transmitted via the dual-port memory in a parallel format. That is, all data can individually and simultaneously pass the dual-port memory 270. The switch device 120 uses the second CPU 220 to arrange the path routing of the standard packet according to a path selection setting (e.g. a routing table) stored in a storage medium. The second CPU 220 transmits the standard packet to the local computer 152 of the destination. Afterwards, the standard packet is transmitted via the UART's and half-duplex communication processor 216 to the computer connection port 212 of its destination. After being converted into electrical signals complying with the connection agreement of the local computer 152 of its destination, it is further transmitted to the local computer 152 of its destination. As shown in FIG. 3, the standard packet 300 contains a first protocol section 302 and a standard data section 304. The first protocol section 302 stores protocol codes, defining the packet protocol of the standard packet 300. The standard data section 304 follows the predetermined or manufacturer defined connection agreement or format to store the electrical signals of local manipulating devices 154, such as the keyboard and mouse. The standard data section 304 of the standard packet transmitted from the local computer 152 to the local manipulating deice 154 also satisfies the above rules. The disclosed KVM switch unifies the connection agreement used inside the KVM switch to increase the data transmission speed and efficiency. Aside from the interfaces of the computers and the manipulating devices, the designs of other circuits inside the KVM switch do not require one to take into account the connection agreement compatibility issue. Therefore, the invention not only increases the data exchange efficiency and compatibility, but also reduces the design complexity and product costs. As another embodiment shown in FIG. 4, the KVM switch 400a uses several second interfaces 112 (e.g. USB, COM, PS/2, infrared, Bluetooth, and other wired or wireless interfaces) to connect several local computers 152 and uses several first interfaces 114 (e.g. USB, COM, PS/2, infrared, Bluetooth, and other wired or wireless interfaces) to connect several local manipulating devices 154, such as the keyboard and mouse. For demonstration purposes, we draw only one first interface 114 and one second interface 112 in FIG. 4. Similar to the previous embodiment, the first interface 114 further has a first converting device 164 to convert local electrical signals into standard packets in order for the switch device 120 to arrange path routing. The second interface 112 has a second converting device 162 to convert the standard packet into electrical signals with the same connection agreement as the local computer 152 of its destination before sending to the local computer 152. According to the path selection setting, when the path destination of the local electrical signals is a local computer 152, the switch device 120 (e.g. a switch chip, programmable chip or CPU) transmits the local electrical signals to the second interface 112 of its destination before sending to the local computer 152. When the path destination of the local electrical signals is a remote computer, such as one connecting to another KVM switch 400b, the switch device 120 transmits the local electrical signals to the packet encoding device 422. The packet encoding device 422, such as a programmable chip or CPU, generates according to the local electrical signals at least one network packet having several data sections correspondingly storing the local electrical signals received by the first interfaces 154. The network device 430 establishes communications with the network devices of other KVM switches 400b using a network protocol, such as the Ethernet or wireless network protocol, to transmit network packets generated by the packet encoding device 422 and to receive those transmitted by another KVM switch. The packet decoding device 424, such as a programmable chip or CPU, decodes the network packet transmitted from another KVM switch 400b to obtain at least one remote electrical signal. The switch device 420 distributes the remote electrical signal according to the path selection setting to the second interface 112 of its destination before sending it to the local computer 152 of its destination. In FIG. 5, several second interfaces 112 connect to several local computers 152 via several computer connection ports 212. The connection agreement of each of the computer connection ports 212 is the same as that of the connected local computer 152. Several first interfaces 114 connect to several local manipulating devices 154 via several manipulating device connection ports 214. The connection agreement of each of the manipulating device connection ports 214 is the same as that of the connected local manipulating device 154. For demonstration purposes, we draw only one manipulating device connection port 214 and computer connection port 212 in FIG. 5. The electrical signals between the local computer 152 and the KVM switch 500a are transmitted using a set of universal asynchronous receivers/transmitters (UART's) and half-duplex communication processor 216. The electrical signals between the local manipulating devices 154 and the KVM switch 500a are also transmitted using the same set of universal asynchronous receivers/transmitters (UART's) and half-duplex communication processor 216. The KVM switch 500a in the preferred embodiment can simultaneously connect to 32 local computers 152 and four local manipulating devices 154. That is, the KVM switch 500a has 32 computer connection ports 112 and 4 manipulating device connection ports 114. Therefore, it requires four 9-port UART's and one half-duplex communication processor for electrical signal transmissions. The half-duplex communication processor can be replaced by a more expensive full-duplex communication processor or some other suitable processor. The manipulating device connection port 214 is the first converting device 164 while the computer connection port 212 is the second converting device 162. The CPU of them processes conversions between electrical signals and standard packet that have different connection agreements. The standard packet complies with the predetermined connection agreement, such as the USB connection agreement, or manufacturer defined format. This unifies the connection agreement used in the KVM switch 200. The data transmission speed and efficiency can also be increased through appropriate designs. Moreover, the preferred embodiment provides a first CPU 260 and a dual-port memory 270 in order to quickly process data exchanges between the manipulating device connection port 214, the computer connection port 212 and the second CPU 220. All the data from the manipulating device connection port 214 and the computer connection port 212 are transmitted via the dual-port memory in a parallel format. That is, all data can individually and simultaneously pass the dual-port memory 270. The switch device 120 uses the second CPU 220 to arrange the path routing of the standard packet according to a path selection setting (e.g. a routing table) stored in a storage medium. The second CPU 220 transmits the standard packet to the local computer 152 of the destination. Afterwards, the standard packet is transmitted via the UART's and half-duplex communication processor 216 to the computer connection port 212 of its destination. After being converted into electrical signals complying with the connection agreement of the local computer 152 of its destination, it is further transmitted to the local computer 152 of its destination. When the path destination of the electrical signals is a remote computer, the second CPU 220 performs packet encoding. At least one network packet with several data sections correspondingly storing the standard packets of the manipulating device connection ports 214 is generated according to the standard packet. The standard packet is transmitted to the network device 430. The network device 430 includes a network interface chip (NIC) 232 and a network switch 234 to transmit the network packets generated by the second CPU 220 and to receive those transmitted by another KVM switch 500b. The network switch 234 has a first port 264, a second port 274, and a third port 284, where the first port 264 connects to the NIC 232 whereas the second port 274 and the third port 284 can connect to another KVM switch 500b. According to the preferred embodiment, the network device 430 further contains a 2-way switch 236 connected to the second port 274 for selecting between the Ethernet and another KVM switch 200b. The 2-way switch 236 is controlled by the second CPU 220. When the 2-way switch switches to the Ethernet, the KVM switch 500a can download new firmware via the Ethernet for update. A remote manager can also manage and monitor the KVM switch 500a or keep track of its operation record via the Ethernet. In the preferred embodiment, the KVM switch is set in such a way that when it is connected with several KVM switches, the 2-way switch of the first KVM switch is connected to the Ethernet while others connected with one another. The firmware downloaded via the first KVM switch is forwarded to other KVM switches. The transmissions and reception of the network packets are performed following the Ethernet protocol. However, people skilled in the art can use other settings or network protocols without departing from the spirit and scope of the invention. After the network switch 234 receives a network packet from another KVM switch 500b, the NIC 232 transfers the network packet to the second CPU 220. The second CPU 220 obtains from the network packet at least one remote electrical signal whose path destination is a local computer 152. Therefore, the second CPU 220 transmits the remote electrical signal to the computer connection port 212 of the destination and to the local computer 152 of the destination according to the path selection setting. Likewise, the second CPU 220 first transmits the remote standard packet to the first CPU 260 and the dual-port memory 270. Afterwards, the standard packet is transmitted to the computer connection port 212 of its destination via the UART's and half-duplex communication processor 260. After being converted by the computer connection port 212 into the electrical signals complying with the connection agreement of the local computer 152 of its path destination, the electrical signals are transmitted to the local computer 152. Besides, the functions of the switch device 120, the packet encoding device 122, and the packet decoding device 124 in the preferred embodiment are implemented using the same second CPU 220. Thus, the devices in the current embodiment are not necessarily implemented independently. When the operating clock of the CPU is fast enough, one may even use a single CPU to achieve the functions of the second CPU 220, the first CPU 260, and the dual-port memory 270. That is, these devices can share one or several programmable chips or CPU's using an appropriate program. As shown in FIG. 6, the KVM switch 500a can simultaneously connect to four local manipulating devices 154. Therefore, the network packet 600 has four data sections 614a, 614b, 614c, 614d correspondingly storing the standard packets of the manipulating device connection ports 214. The contents of each data section are the first protocol section 302 and the standard data section 304 of each standard packet. The connection agreement or format of the electrical signals of each manipulating device connection port 214 is converted and unified by the first converting device 164 and the second converting device 162 into several standard packets with a single connection agreement. When encoding the standard packet of each manipulating device connection port 214 into data sections, different procedures are done to different connection agreements. Therefore, the invention can greatly reduce the design difficulty and production costs of the packet encoding device 422, the packet decoding device 424, the network device 430, and the software. Moreover, the network packet 600 further contains a network overhead section 602 and a protocol section 612. Under the Ethernet protocol used herein, the network overhead section 602 stores the Ethernet overhead, such as the NIC address. The protocol section 612 stores the protocol codes, defining the packet protocol of the network packet 600. In the preferred embodiment, when two or more local manipulating devices 154 access remote computers that connect to the same other KVM switch 500b, the electrical signals of the local manipulating devices 154 are encoded and stored in the same network packet. The electrical signals from two or more different local manipulating devices 154 are transmitted using the same network packet such that no signal delay occurs to the remote computers connecting to the same other KVM switch 500b. The KVM switch in the current embodiment uses its network device to connect to others in order to communicate with more manipulating devices and computers. Since the electrical signals of different connection agreements or formats are converted into a standard packet using one single connection format, one does not need to have different procedures when encoding the standard packet into the data sections. This can greatly reduce the design difficulty and production costs of the packet encoding device, the packet decoding device, the network device, and the software. The network device can include cheap NIC's and network switches, connecting to the network devices of other KVM switches using a technically mature and unified network protocol. In addition to lowering the design and production costs, the KVM switch can more easily and directly connect to the external network environment, facilitating firmware upgrades. It further enables managers to directly manage and monitor the KVM switch or keep track of its operation record via the network. Furthermore, the preferred embodiment uses a network packet to transmit electrical signals of remote computers with path destinations being connected to the same KVM switch. This prevents the problem of signal delay as in the prior art due to sorting and waiting. This enables multiple KVM switches connected together to rapidly exchange data, increasing the efficiency and extensibility of the KVM switches. Certain variations would be apparent to those skilled in the art, which variations are considered within the spirit and scope of the claimed invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of Invention The invention relates to a switch device and, in particular, to a KVM switch for multiple chaining and with high compatibility and the method thereof. 2. Related Art With the rapid development in information technology, computers and their peripherals become very popular. Computer users often use the mouse and keyboard to control the computers. Through the monitors or speakers, the computer users can monitor the state of the computers. Sometimes a user may have more than one computer to process different types of things. Traditionally, each computer is equipped with one set of input/output (IO) peripheral devices, including the keyboard, mouse, monitor, and speakers. However, this is a waste of money and space if one has several computers. On the other hand, large system businesses or enterprise internal networks often involve tens to thousands servers. Each server needs a monitor, a keyboard and a mouse to for management. In practice, one rarely needs to manipulate these devices. Most of the time, the servers do not need to be controlled by the manager. In this situation, it is totally unnecessary, costly, and wasting the space to have a set of IO peripheral devices for each server. Therefore, a keyboard video mouse (KVM) switch is proposed to use at least one set of operation device to manage several computers. Using the KVM switch does not only solve the cost problem, it simultaneously solves the problems of equipment and space. It may also conquer the compatibility problem among different interfaces. However, due to the hardware design and cost restriction of an individual KVM switch, the number of manipulating devices and computers it can accommodate is limited. On the other hand, it is not easy to connect conventional KVM switches together. When several manipulating devices simultaneously access multiple computers, the connection agreements among the manipulating devices and computers are often different. The commonly used connection agreements include the universal serial bus (USB) interface, the serial port (COM) interface, or the personal system/2 (PS/2) interface. The different connection agreements will reduce the compatibility of the KVM switches and the signal exchange efficiency among them. For example, when the connection agreement of the keyboard is the USB interface while that of the computer is the PS/2 interface, the conventional KVM switch usually converts the electrical signal to/from the keyboard to be PS/2 compatible. Nevertheless, such a method is not suitable for multiple chaining KVM switches. If they need to transmit electrical signals in different connection agreements, their circuits have to be able to understand various connection agreements. This does not only increase the design difficulty, the compatibility is still an issue that serious reduce its efficiency. The above-mentioned drawbacks result in a lot of inconvenience in practical uses. For large system businesses or the internal networks of mid-size enterprises, in particular, if the KVM switches cannot simultaneously support a large number of manipulating devices and computers, they do not only increase the costs for constructing and maintaining the system but also reduce the communication efficiency of the whole network. | <SOH> SUMMARY OF THE INVENTION <EOH>An objective of the invention is to provide a KVM switch to improve the compatibility when there are different connection agreements. It further enables multiple chaining of KVM switches and thus allows connections to more manipulating device and computers. The invention also reduces the design difficulty. Another objective of the invention is to provide a computer switching method to improve the data exchange efficiency, compatibility, and extensibility of the KVM switches. The connected KVM switches can thus rapidly exchange data. Pursuant to the above objectives, this specification discloses a KVM switch and the method thereof. A plurality of local and remote computers share a plurality of local manipulating devices using a plurality of KVM switches, where the connection agreements of the computers and the manipulating devices are different. A plurality of first electrical signals of the manipulating devices are received, where each of the first electrical signals complies with the connection agreement of the source manipulating device. Each of he first electrical signals is converted into a standard packet. The paths of the standard packets are routed between the manipulating devices and the computers. Afterwards, each of the standard packets is converted into a second electrical signal that complies with the connection agreement of the destination computer. The disclosed KVM switch contains at least a plurality of first interfaces, a switch device, and a plurality of second interfaces. The first interfaces are connected to the manipulating devices to receive the first electrical signals, each of which complies with the connection agreement of the source manipulating device. Each first interface has a first converting device to convert the first electrical signal into a standard packet. The switch device determines the paths of the standard packets between the manipulating devices and the computers according to a path selection setting. The second interfaces are connected to the computers. Each second interface has a second converting device to convert the standard packet received from the switch device into a second electrical signal that complies with the connection agreement of the connected computer. According to a preferred embodiment of the invention, the switch device contains a central processing unit (CPU). Each of the electrical signals is selected from a keyboard signal and a mouse signal. The first interfaces contain several universal asynchronous receivers/transmitters (UART's), a half-duplex communication processor, and a CPU. The second interfaces also contain several UART's, a half-duplex communication processor, and a CPU. According to another embodiment of the invention, when the KVM switch provides a plurality of local and remote computers to share a plurality of local manipulating devices, the KVM switch further contains a packet encoding device, a network device, and a packet decoding device. The packet encoding device generates at least one network packet that contains a plurality of data sections correspondingly storing the standard packets of the first interfaces according to the standard packet. The network device communicates with another KVM switch using a network protocol in order to transmit network packets and to receive network packets from another KVM switch. The packet decoding device obtains at least one remote standard packet from the network packet transmitted by another KVM switch. According to the preferred embodiment, the network packet has a network overhead section. When the path destinations of the standard packets are the remote computers connected to the same remote KVM switch, the standard packets are encoded into a single network packet. The packet encoding device contains a CPU; the packet decoding device also contains a CPU. They may share the same CPU for both encoding and decoding. The network device contains a network interface chip (NIC) and a network switch. The NIC connects to the packet encoding device and the packet decoding device. The network switch has a first port, a second port, and a third port. The first port connects to the NIC. One of the second and third ports is for the connection of another KVM switch. The network device further contains a two-way switch connected to the second port for switching between the Ethernet and another KVM switch. | 20040415 | 20091103 | 20051020 | 75402.0 | 1 | PEYTON, TAMMARA R | KEYBOARD VIDEO MOUSE (KVM) SWITCH WHEREIN PERIPHERALS HAVING SOURCE COMMUNICATION PROTOCOL ARE ROUTED VIA KVM SWITCH AND CONVERTED TO DESTINATION COMMUNICATION PROTOCOL | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,824,531 | ACCEPTED | Blender and mugs | A blender system composed of a mixing base that is capable of agitating the contents of a plurality of containers. The mixing base includes a means for rotating a shaft, a recessed well positioned at a top of the mixing base, a pressure-actuated switch positioned about the periphery of the recessed well, and a locking groove. One container that may be used with the mixing base is a container having an opening at one end and a base at a second end, where the base is tapered. The container also includes one or more locking members and in spaced relation about the periphery of the container body. The container body may also include a handle that is coupled to the exterior of the container. The container also includes a ring that is selectively attachable and removable from the periphery of the opening such that when the ring is coupled to the container, the user is able to drink from the container without spilling or dripping. | 1. A blender system, comprising: a base having a means for rotating a shaft, a recessed well positioned at a top of the base, a pressure-actuated switch positioned about the periphery of the recessed well, and one or more locking grooves; a container comprising an opening at one end and a base at a second end, the body being tapered at the second end; a handle coupled to an exterior of the body; one or more locking members in spaced relation about a periphery of the opening of the body, wherein the locking members are engageable with the locking grooves; a ring selectively attachable and removable from the periphery of the opening; and a means for agitating contents of the container, the means selectively attachable and removable from the opening of the body. 2. The blender system of claim 1 further comprising a lid having a generally planar top and a wall coupled to a periphery of the top, the top having a plurality of openings, and wherein the lid is selectively attachable and removable from the opening of the container. 3. The blender system of claim 1 wherein the container further comprises one or more threads positioned on the periphery of the opening. 4. The blender system of claim 3 wherein the ring comprises at least one wall and a lip coupled to a top of the at least one wall. 5. The blender system of claim 1 wherein the container further comprises one or more ridges positioned on an interior of the body. 6. The blender system of claim 1 wherein the agitating means comprises a mixer base and one or more blades rotatably coupled to the mixer base. 7. A container for a blender, comprising: a body having an opening at one end and a base at a second end, the body being tapered at the second end; a handle coupled to an exterior of the body; a stop ridge positioned below the opening and extending from the exterior of the body; one or more locking members in spaced relation about a periphery of the stop ridge; and a ring selectively attachable and removable from the periphery of the opening. 8. The container of claim 7 further comprising one or more threads positioned on the periphery of the opening, wherein the threads are positioned above the stop ridge. 9. The container of claim 7 further comprising a means for agitating contents of the container, the means selectively attachable and removable from the opening. 10. The container of claim 9 wherein the agitating means is one or more blades rotatably coupled to a mixer base. 11. The container of claim 7 wherein the ring comprises at least one wall and a lip coupled to a top of the at least one wall. 12. The container of claim 7 further comprising one or more ridges positioned on an interior of the body. 13. The container of claim 7 wherein the handle is generally C-shaped. 14. A blender system, comprising: a base having a means for rotating a shaft, a recessed well positioned at a top of the base, a pressure-actuated switch positioned about the periphery of the recessed well, and one or more locking grooves; a container comprising an opening at one end and a base at a second end, the body being tapered at the second end; a handle coupled to an exterior of the body; one or more locking members in spaced relation about a periphery of the opening of the body, wherein the locking members are engageable with the locking grooves; and one or more container threads positioned about the periphery of the opening; a ring comprising at least one ring wall and a lip, the lip coupled to a top of the at least one ring wall, the ring wall having one or more ring threads positioned on an interior portion the ring wall, the ring threads selectively attachable and removable from the container threads; a means for agitating contents of the container, the means selectively attachable and removable from the container threads; and a lid having a generally planar top and a lid wall coupled to a periphery of the top, the top having a plurality of openings, and wherein the lid is selectively attachable and removable from the container threads. 15. The blender system of claim 14 wherein the agitating means comprises a mixer base and one or more blades rotatably coupled to the mixer base. 16. The blender system of claim 14 wherein the openings on the lid are positioned on a portion of the lid. 17. The blender system of claim 14 wherein the lid further comprises one or more threads positioned on an interior of the lid wall. 18. The blender system of claim 14 wherein the container further comprises one or more ridges positioned on an interior of the body. | CROSS-REFERENCE TO RELATED APPLICATIONS This Application is a continuation-in-part application of U.S. patent application Ser. No. 10/649,757, filed on Aug. 26, 2003, which is hereby incorporated by reference. BACKGROUND Various devices for blending various liquids and solids have been developed over the years. These devices have various features and options to suit a wide variety of uses and applications. For example, there are many blenders that are either handheld or freestanding devices. While these devices have been useful, these prior art devices can be difficult to clean, use and store unused products, especially, when preparing smaller batches. More specifically, freestanding devices can be too large and cumbersome to use to make smaller portions and are generally better designed for blending larger quantities of fluids and ingredients. Handheld units may be useful to make individualized portions, but they may lack the power to properly blend ingredients together. Furthermore, these handheld units are generally used with open containers such as bowls or cups that can increase the chances of spilling or splattering during preparation of the ingredients. Moreover, the unused portion would have to be poured out of the open container and into a sealable container to be stored or to be readily carried by a person. Accordingly, there remains a need for an individualized blender system that may be easier to use, clean and store unused products. SUMMARY Exemplary embodiments disclosed here are directed to an individualized blender system. According to one exemplary embodiment, the blender system is composed of a base including a motor means, an individual-sized container and a combination blender and/or juicer canister. The base includes a body, a motor means, an agitating means coupled to the motor, a recessed well for receiving a container and a pressure-sensitive switch that selectively powers the motor means. In use, the container or canister may be placed on the base, pressure is applied to the container or canister thereby activating the motor means and agitating the contents of the container or canister. The base also includes a locking groove that permits the user to lock the container or canister on the base while keeping the motor means in the powered position. According to one exemplary embodiment, the individually sized container may be bullet-shaped. In alternate embodiments, the container may have a cylindrical, polygonal, cubical, or pyramidal shape. Also, the container may be sealed with a simple cap or a cap having an agitating means. The container may also include a plurality of ridges that form a stable platform for standing the container like a typical drinking vessel. That is, the bullet-shape container may be inverted so that the container rests on the ridges, and the cap is readily accessible. Additionally, the container may include locking members that engage the locking grooves provided on the blender base. According to one exemplary embodiment, the blender canister includes, at a minimum, a body, a selectively removable base having an agitating means, locking members that engage the locking grooves provided on the blender base and a selectively removable means for sieving the container contents. In use, with the sieving means provided in the body of the blender canister, fruits and vegetables may be placed and blended within the bore of the sieving means. The pulp remaining from the fruits and vegetables remain within the bore of the sieving means and the resultant juice may be decanted from the blender canister. Alternatively, the blender canister may be used without the removable means for sieving the container contents. According to another embodiment, a container that may be used with a mixing base has an opening at one end and a base at a second end, where the second end is tapered. The container may also include one or more locking members in spaced relation about the periphery of the container body. The container body may also include a staying means that is coupled to the exterior of the container. The container may also include a ring that is selectively attachable and removable from the periphery of the opening such that when the ring is coupled to the container, the user is able to drink from the container without spilling or dripping. Another embodiment is directed to caps that may be coupled to one or more of the containers disclosed herein. The cap may have a generally planar top surface and at least one sidewall. The cap may be secured over the openings of the container via one or more coupling means. The cap may also include openings that are spaced about the top of the container. The openings may have varying sizes, shapes, and density on the cap depending upon the intended or desired use. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an exemplary embodiment of the blender system; FIG. 2A is a perspective view of an exemplary embodiment of an individualized blender container; FIG. 2B is an exploded perspective view of FIG. 2A; FIG. 2C is an inverted perspective view of FIG. 2A; FIG. 2D is a perspective view of another exemplary embodiment of an individualized blender container; FIG. 3 is a perspective view of an exemplary embodiment of a blender base; FIG. 4 is a top plan view of FIG. 3; FIG. 5 is a cross-sectional view of an exemplary embodiment of a blender base taken along line 5-5 of FIG. 4; FIG. 6 is a cross-sectional view of an exemplary embodiment of a blender base taken along line 6-6 of FIG. 5; FIG. 7 is a side view of an exemplary embodiment of a blender container; FIG. 8 is a perspective view of an exemplary embodiment of a blender container; FIG. 9 is a perspective view of an exemplary embodiment of blender container base; FIG. 10 is a cross-sectional view of an exemplary embodiment of blender container taken along line 10-10 of FIG. 7; FIG. 11 is a perspective view of one embodiment of a mug that may be used with the blender; FIG. 12 is a perspective view of the embodiment of FIG. 11 with an exemplary embodiment of a ring removed from the mug; FIG. 13 is a bottom perspective view of ring of FIG. 12; FIG. 14 is a perspective view of one embodiment of a mug that is coupled to a blender base; FIG. 15 is a perspective view of a top for a blender container; and FIG. 16 is another embodiment of a top for a blender container. DETAILED DESCRIPTION The detailed description set forth below in connection with the appended drawings is intended as a description of exemplary embodiments and is not intended to represent the only forms in which the exemplary embodiments may be constructed and/or utilized. Turning to the drawings, FIG. 1 is directed to an exemplary embodiment of an individualized blender system. More specifically, FIG. 1 shows a container 101 engaged to a blender base 100 and a blender container 106. As shown in the exemplary embodiment of FIG. 1, the container 101 is a bullet-shaped container. As those skilled in the art will appreciate, the container 101 may have a plurality of shapes known or developed in the art. Also, the container 101 may include a plurality of ridges 102 provided on the outer surface of the container 101. The container 101 also includes a means for agitating 108 the contents of the container. The means for agitating 108 the container contents can be a blade element coupled to an impeller in a shaft or other transmission means. The blade element may have one, two, three, four, or more cutting elements. The cutting elements are generally flat members that may have sharpened edges, pointed tips, and one or more bends along the surface of the cutting elements. The blender container 106 also includes a base 110, selectively removable lid 104, 105, and a base member 110 that is coupled to an agitating means 108. As shown in FIG. 1, the lid is composed of two components, but it is contemplated that a one-piece or multi-piece cap may also be used. The lid 104 may be locked on to the opening of the container 106 via a cap-locking member 107. The cap-locking member 107 may be an L-shaped ridge located at the lip of the container 106. The cap-locking member 107 engages a corresponding member (not shown) on the lid 104 in order to securely fix the lid 104 to the container 106. According to one exemplary embodiment, the blender container 106 may include a juicer element 111. The juicer element 111 is composed of a main body 113 and a plurality of sieve elements 114 spaced about the periphery of the main body 113. According to the exemplary embodiment depicted in FIG. 1, the juicer element 111 may also include a funnel 112 at one end of the main body 113. Additionally, the juicer element 111 may also include an annular stop member 115 positioned at one end of the juicer so as to prevent over-insertion of the juicer element 111 into the blender container 106. FIGS. 2A through 2C illustrate various views of the individualized container 101. That is, an individualized container 101 is sized for smaller servings that would be prepared/consumed by one and/or a few individuals. As shown in FIG. 2A, the container 101 is resting on external ridges 102. The external ridges 102 are shaped so as to permit the container 101 to rest on the apex of the container 101 without tipping over. As those skilled in the art will appreciate, the number of ridges 102 may be varied from what is depicted so long as the container 101 can stand upright on a substantially flat surface. As shown in FIG. 2A, the container 101 may be used as a drinking vessel. That is, an individual may blend contents of the container 101, remove the container 101, base 100, access the contents of the container, and secure the cap 200 onto the container 101 to store for later use. In one configuration, the container 101 may be also enclosed with a cap 200. In an alternate configuration, the container 101 may be enclosed with a base 202 having an agitating means 203 as shown in FIG. 2D. As shown in FIG. 2C, the cap 200 may be affixed to the opening of the container 101 by threads 204. As those skilled in the art will appreciate, the cap 200 may be secured to the container 101 by various known and developed means such as, but not limited to, a friction fit or a snap-fit. As shown in FIG. 2B, the container 101 is inverted and may rest on the cap 200. FIG. 2D illustrates an alternate embodiment of the container 101 having a larger volume as compared to the embodiments depicted in FIGS. 2A-2C. Also, the base 202 includes another exemplary embodiment of an agitating means 203. Additionally, as shown in FIGS. 2A through 2C, the container 101 includes locking members 201 that are spaced about the periphery of the container 101. The locking members 201 allow the user to operate the blender without requiring the constant application of force to the container (in order to keep the motor means switched on). FIG. 3 is directed to the base 100 and the various components that are associated with the base's recessed well 300. The base 100 includes a motor means (not shown) that is coupled to an impeller 301. The impeller 301 includes a plurality of blades 303 that radiate from the center of the impeller 301. Along the periphery of the recessed well 300, a plurality of bushings 305 may be placed about the periphery of the recessed well 300. In another exemplary embodiment of the base 100, the base does not include the bushings 305. The bushings 305 may be made from a generally resilient material such as, but not limited to, rubber or silicone that may serve to reduce the vibrations during the agitation of the container contents. Also, as shown in FIG. 3, the recessed well 300 includes a plurality of pressure-activated switches 302. In use, the weight of the container 101 or the blender container 106 causes the downward movement of the switch 302 thereby activating the motor means. As shown in FIG. 3, a locking groove 304 may be provided adjacent to the switch 302. Accordingly, in use, when the locking members 201 contact and depress the switch 302, the container 101, 106 may be rotated such that the locking member 201 engages the locking groove 304. That is, as shown in FIG. 6, when a force F1 is applied to the switch 302, the switch 302 moves downward. This downward motion causes the cam 600 on the switch 302 to contact a switching means 501 that is connected to the motor 500 thereby powering the motor. Accordingly, depending on the intended use or application, the container 101, 106 may be depressed to activate the motor 500 for short periods of time. Alternatively, the container 101, 106 may be depressed and rotated slightly so as to allow the locking members 201 to engage the locking groove 304 to permit the continued operation of the motor 500 without requiring the user to exert constant pressure to keep the motor powered. FIG. 7 is directed to an exemplary embodiment of the blender container 106. The blender container 106 comprises a main body that defines a volume and a lid 104, 105 that is affixed thereto. The lid includes a plurality of openings 700 that may be used to decant the contents of the container 106 while the lid 104 remains affixed to the container 106. The blender container 106 also includes a base 110. The base 110 is sized to fit within the recessed well 300. Also, the base 110 is coupled to the container 106 by a screw-fit relation. The base 110 also includes an agitating means 108, as shown in FIG. 9. Turning back to FIG. 7, the blender container 106 also includes a plurality of locking members 109 spaced about the periphery of the blender container 106 near the base 110 of the container 106. As shown in the exemplary blender container 106 depicted in FIG. 7, a juicer 111 may be provided within the body of the blender container 106. As those skilled in the art will appreciate, the blender container 106 may be used without the juicer 111. The blender container 106 may include a handle 800 and a spout 801 that facilitates the decanting of the contents of the container. FIG. 10 illustrates the cross-sectional view of the blender container 106. The cross-sectional view shows the juicer element 111 placed within the body of the blender container 106. As shown in FIG. 10, the juicer element 111 is secured to the bottom of the blender container 106. Additionally, the bore of the juicer 111 may be accessed by removing cap element 105. In use, fruits and/or vegetables may be placed into the bore 1003 of the juicer 111. Rotation of the motor means is transmitted through shaft 1000 and mating impeller 1001 thereby transmitting a rotational force to the agitating means 108. The contents of the juicer 1003 are then blended thereby causing the resulting juice to move from the bore 1003 into the container body 1002 through the sieve elements 114. The remaining pulp is separated and trapped within the bore 1003 of the juicer 111. By providing a two-part cap 104, 105, an individual user can access the bore 1003 of the juicer 111 without removing the entire cap or stopping the machine for fear of spillage or splattering. For example, the individual user may remove cap 105 to access the bore 1003 of the juicer 111 to add more products for juice extraction. The resulting juice that is located within the space 1002 may be decanted from the container without removing the lid through the openings. FIG. 11 illustrates one embodiment of a mug-type container 1100. The container 1100 includes at least one wall 1101 that defines a fluid containing area. As shown in the figure, the wall 1101 may be slightly tapered when moving from the mouth of the container 1100 to the base of the container 1100. The container 1100 also includes a mean for grasping or holding the container 1102. In another embodiment, the means may be a handle 1102, which is fixed to the outer wall 1101. In one embodiment, the handle 1102 is a generally U-shaped. In other exemplary The container 1100 also includes a plurality of locking members 1104 that are positioned about the periphery of the container 1100. In one embodiment, the locking members 1104 are protuberances that extend substantially perpendicular from the wall 1101 of the container 1100. Also as shown in FIG. 11, the members 1104 have a generally rectangular shape. As those skilled in the art will appreciate, locking members 1104 may have a plurality of different shapes. As shown in FIG. 12, the container 1100 is provided with a plurality of threads 1200 on the outer wall 1101 that allow the ring 1103 to be coupled to the container 1100. As shown in the embodiment depicted in FIG. 11, the members 1104 may be coupled to a ring-shaped ridge 1105. The ridge 1105 may also serve as a stop so that the ring 1103 is not over threaded beyond the opening of the container 1100. The container 1100 may also include a ring 1103 that is positioned atop the mouth of the container 1100. The ring 1103 may be fixed to the container 1100 via threads or other coupling means known or developed in the art. FIG. 13 shows one embodiment of the ring 1103 that may be coupled to the mouth of the container 1100. In one embodiment, the ring 1103 is a generally cylindrical wall having an outer surface and inner surface. The ring 1103 may include a plurality of threads 1300 that are found on the inner surface of the ring 1103. In another embodiment, the ring 1103 includes a top surface or lip that is coupled to the wall of the ring 1300. The ring 1103 may be coupled over the threads 1200 of the container 1100 so that it is easier for an individual to drink from the container 1100. may be coupled over the threads 1200 of the container 1100 so that it is easier for an individual to drink from the container 1100. FIG. 14 illustrates one exemplary embodiment of the container 1100 as fixed to a blender base 110. According to one embodiment, the container 1100 is inverted and threadedly coupled to the blender base 110. The container 1100 may then be inserted into the recess well 300 of the blender base of a blender 100. As shown in FIG. 14, the base of the container 1100 is slightly tapered. The taper of the container 1100 creates a dome-like structure that facilitates the blending of the contents of the container 1100. FIGS. 15 and 16 illustrate exemplary embodiments of a container cap 1500, 1600, respectively, that may be coupled to a container 101, 1100. The cap 1500, 1600 contains a generally planar top surface 1502, 1103 and at least one sidewall 1503, 1604. According to various embodiments, the tops 1002, 1603 of the container cap 1500, 1600 and the sidewalls 1503, 1604 are generally perpendicular to one another. As those skilled in the art will appreciate, the caps 1500, 1600 may secure to the containers 101, 1100 by a coupling means. In another embodiment, the coupling means may be ridges for a snap fit. In one embodiment, a plurality of threads (not shown) may be provided on the inner surface of the wall 1503, 1604. The threads are sized to engage the threads that are on the plurality of the containers 101, 1100 that are described herein. As shown in FIG. 15, the container may include a plurality of openings 1501 that are spaced about the top of the container cap 1500. The openings 1501 may have varying sizes, shapes, and density on the cap 1500. As shown in FIGS. 15 and 16, these openings 1501, 1601, 1602 are generally circular in shape. As those skilled in the art will appreciate, these openings 1501, 1601, 1602 may have a plurality of different shapes know or developed in the art. Furthermore, the clustering or density of the openings on the cap 1500, 1600 may be varied depending upon intended use of the container cap 1500, 1600. For instance, the cap 1500, as shown in FIG. 15, may be used for shaking out large or coarse items that are contained within the container 1500. In FIG. 16, the openings 1601, 1602 being in closer proximity to each other may be useful for those blended items that have a smaller diameter or that may be poured or strained out of the container 1100. In closing, it is understood that the embodiments described herein are merely illustrative of the principles of these varying embodiments. Other modifications that may be made are within the scope of these embodiments described herein. Thus, by way of example, but not of limitation, alternative configurations may be utilized in accordance with the teachings herein. Accordingly, the drawings and description are illustrative and not meant to be a limitation thereof. | <SOH> BACKGROUND <EOH>Various devices for blending various liquids and solids have been developed over the years. These devices have various features and options to suit a wide variety of uses and applications. For example, there are many blenders that are either handheld or freestanding devices. While these devices have been useful, these prior art devices can be difficult to clean, use and store unused products, especially, when preparing smaller batches. More specifically, freestanding devices can be too large and cumbersome to use to make smaller portions and are generally better designed for blending larger quantities of fluids and ingredients. Handheld units may be useful to make individualized portions, but they may lack the power to properly blend ingredients together. Furthermore, these handheld units are generally used with open containers such as bowls or cups that can increase the chances of spilling or splattering during preparation of the ingredients. Moreover, the unused portion would have to be poured out of the open container and into a sealable container to be stored or to be readily carried by a person. Accordingly, there remains a need for an individualized blender system that may be easier to use, clean and store unused products. | <SOH> SUMMARY <EOH>Exemplary embodiments disclosed here are directed to an individualized blender system. According to one exemplary embodiment, the blender system is composed of a base including a motor means, an individual-sized container and a combination blender and/or juicer canister. The base includes a body, a motor means, an agitating means coupled to the motor, a recessed well for receiving a container and a pressure-sensitive switch that selectively powers the motor means. In use, the container or canister may be placed on the base, pressure is applied to the container or canister thereby activating the motor means and agitating the contents of the container or canister. The base also includes a locking groove that permits the user to lock the container or canister on the base while keeping the motor means in the powered position. According to one exemplary embodiment, the individually sized container may be bullet-shaped. In alternate embodiments, the container may have a cylindrical, polygonal, cubical, or pyramidal shape. Also, the container may be sealed with a simple cap or a cap having an agitating means. The container may also include a plurality of ridges that form a stable platform for standing the container like a typical drinking vessel. That is, the bullet-shape container may be inverted so that the container rests on the ridges, and the cap is readily accessible. Additionally, the container may include locking members that engage the locking grooves provided on the blender base. According to one exemplary embodiment, the blender canister includes, at a minimum, a body, a selectively removable base having an agitating means, locking members that engage the locking grooves provided on the blender base and a selectively removable means for sieving the container contents. In use, with the sieving means provided in the body of the blender canister, fruits and vegetables may be placed and blended within the bore of the sieving means. The pulp remaining from the fruits and vegetables remain within the bore of the sieving means and the resultant juice may be decanted from the blender canister. Alternatively, the blender canister may be used without the removable means for sieving the container contents. According to another embodiment, a container that may be used with a mixing base has an opening at one end and a base at a second end, where the second end is tapered. The container may also include one or more locking members in spaced relation about the periphery of the container body. The container body may also include a staying means that is coupled to the exterior of the container. The container may also include a ring that is selectively attachable and removable from the periphery of the opening such that when the ring is coupled to the container, the user is able to drink from the container without spilling or dripping. Another embodiment is directed to caps that may be coupled to one or more of the containers disclosed herein. The cap may have a generally planar top surface and at least one sidewall. The cap may be secured over the openings of the container via one or more coupling means. The cap may also include openings that are spaced about the top of the container. The openings may have varying sizes, shapes, and density on the cap depending upon the intended or desired use. | 20040413 | 20060627 | 20050303 | 71982.0 | 1 | COOLEY, CHARLES E | BLENDER AND MUGS | SMALL | 1 | CONT-ACCEPTED | 2,004 |
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10,824,784 | ACCEPTED | Memory device and method for writing data in memory cell with boosted bitline voltage | Provided are a method of writing data into a memory cell with a boosted write voltage and a memory device that performs the method. The method involves (a) transmitting data input in response to a write command to a bitline; (b) writing the input data on the bitline into a memory cell capacitor via a memory cell transistor; (c) generating a write boosting signal in response to the write command and a bitline precharge signal; (d) boosting a voltage of a capacitor connected between the write boosting signal and the bitline in response to the write boosting signal; (e) boosting a voltage of the bitline to a predetermined level; and (f) rewriting the input data into the memory cell capacitor with the boosted voltage of the bitline. | 1. A method of writing data into a memory cell of a memory device, comprising: (a) transmitting data input in response to a write command to a bitline; (b) writing the input data on the bitline into a memory cell capacitor via a memory cell transistor; (c) generating a write boosting signal in response to the write command and a bitline precharge signal; (d) boosting a voltage of a capacitor connected between the write boosting signal and the bitline in response to the write boosting signal; (e) boosting a voltage of the bitline to a predetermined level; and (f) rewriting the input data into the memory cell capacitor with the boosted voltage of the bitline. 2. The method of claim 1, wherein the write boosting signal is set to at least one of a boosted voltage level or an external power supply voltage level, which is higher than a power supply voltage level of the memory device. 3. The method of claim 1, wherein in step (a), the boosted voltage level or the external power supply voltage level is applied to gates of isolation transistors connected between the bitline and a sense amplification unit so that the isolation transistors are turned on. 4. The method of claim 1, wherein in step (f), the power supply voltage level of the memory device is applied to the isolation transistors between the bitline and the sense amplification unit. 5. The method of claim 4, wherein the isolation transistors are turned off when the input data is at a logic high level. 6. The method of claim 4, wherein the isolation transistors are turned on when the input data is at a logic low level, and then the boosted voltage of the bitline is dropped to a ground voltage level by the sense amplification unit. 7. A memory device, comprising: wordlines, which are connected to gates of memory cell transistors; bitlines, which are connected to drains of the memory cell transistors; memory cell capacitors, which are connected to sources of the memory cell transistors; a write boosting signal generation circuit, which generates a write boosting signal in response to a write command, a bitline precharge signal, and a block decoding signal, the block decoding signal selecting a memory cell array including a given memory cell transistor; and capacitors, which are connected between the bitlines and the write boosting signal. 8. The memory device of claim 7, wherein the write boosting signal generation circuit comprises: a PMOS transistor, a source of which is connected to a power supply voltage and a gate of which is connected to the bitline precharge signal; an NMOS transistor, a source of which is connected to a ground voltage, a gate of which is connected to a bitline sensing signal, and a drain of which is connected to a drain of the PMOS transistor; a latch unit, which is connected to the drains of the PMOS transistor and the NMOS transistor; a first NAND gate, which receives an output of the latch unit and the write command; an inverter, which inverts an output of the NAND gate; and a second NAND gate, which is driven by a boosted voltage or an external power supply voltage higher than the power supply voltage, the second NAND gate outputting the write boosting signal in response to an output of the inverter and the block decoding signal. 9. The memory device of claim 7 further comprising: a sense amplification unit, which senses and amplifies a voltage of each of the bitlines; and an isolation transistor, which is located between the bitline and the sense amplification unit, the transistor being gated by a bitline isolation signal. 10. The memory device of claim 9, wherein the bitline isolation signal has a boosted voltage level, when data is written into each of the memory cell capacitors with the write boosting signal inactivated, and has a power supply voltage level, when data is written into each of the memory cell capacitors with the write boosting signal activated. | BACKGROUND OF THE INVENTION This application claims the priority of Korean Patent Application No. 2003-75815, filed on Oct. 29, 2003, in the Korean Intellectual Property Office, the contents of which are incorporated herein in their entirety by reference. 1. Field of the Invention The present invention relates to a semiconductor memory device, and more particularly, to a method of writing data into a memory cell with a boosted bitline voltage, which is higher than a power supply voltage, and a memory device that performs the method. 2. Description of the Related Art A dynamic random access memory (DRAM) includes memory cells, and each of the memory cells is comprised of a transistor and a capacitor. Each of the memory cells, i.e., DRAM cells, stores a logic data value of “1” or “0” according to the amount of electric charge stored in its memory cell capacitor. In general, a data value of 1 is stored in a DRAM cell with a power supply voltage level (VCC), and a data value of 0 is stored in a DRAM cell with a ground voltage level (VSS). Due to the characteristics of a DRAM cell, electric charge leaks from a capacitor of the DRAM cell, and thus a voltage level of data stored in the capacitor of the DRAM cell gradually decreases. Given such electric charge leakage, a data value of 1 is preferably stored with a higher voltage level than the power supply voltage level VCC. Data stored in each DRAM cell is charge-shared between bitlines, and then is sensed and amplified by a bitline sense amplifier. The larger the difference between the amount of electric charge in a cell capacitor holding a data value of 1, and the amount of electric charge of a cell capacitor holding a data value of 0, the higher the efficiency of the bitline sense amplifier sensing data stored in each of the cell capacitors. The amount of electric charge stored in each of the cell capacitors can be increased by increasing the capacitance of each of the cell capacitors. However, since there are numerous restrictions placed on increasing the size of a chip or manufacturing a semiconductor device, there is a clear limit as to the amount by which the capacitance of each of the cell capacitors can be increased. Therefore, in order to achieve a high sensing efficiency with a given amount of electric charge stored in a cell capacitor with a predetermined capacitance, the voltage of bitlines can be increased after the electric charge stored in the cell capacitor is shared between the bitlines, by decreasing capacitance of each of the bitlines. Alternatively, the bitline voltage can be increased during a sensing process by increasing the amount of electric charge stored in the cell capacitor. However, if a data value of 1 is written into a DRAM cell capacitor by charging the DRAM cell capacitor with a higher voltage level than the power supply voltage level (VCC), the amount of electric charge stored in the DRAM cell capacitor increases. SUMMARY OF THE INVENTION The present invention provides a method of writing data into a memory cell with a boosted voltage level, which is not lower than a power supply voltage level. The present invention also provides a memory device that performs the method of writing data into a memory cell. According to an aspect of the present invention, there is provided a method of writing data into a memory cell of a memory device. The method includes (a) transmitting data input in response to a write command to a bitline; (b) writing the input data on the bitline into a memory cell capacitor via a memory cell transistor; (c) generating a write boosting signal in response to the write command and a bitline precharge signal; (d) boosting a voltage of a capacitor connected between the write boosting signal and the bitline in response to the write boosting signal; (e) boosting a voltage of the bitline to a predetermined level; and (f) rewriting the input data into the memory cell capacitor with the boosted voltage of the bitline. The write boosting signal can be set to a boosted voltage level or an external power supply voltage level, which is higher than a power supply voltage level of the memory device. In one embodiment, in step (a), the boosted voltage level or the external power supply voltage level is applied to gates of isolation transistors connected between the bitline and a sense amplification unit so that the isolation transistors are turned on. In one embodiment, in step (f), the power supply voltage level of the memory device is applied to the isolation transistors between the bitline and the sense amplification unit. The isolation transistors can be turned off when the input data is at a logic high level. The isolation transistors can be turned on when the input data is at a logic low level, and then the boosted voltage of the bitline can be dropped to a ground voltage level by the sense amplification unit. According to another aspect of the present invention, there is provided a memory device. The memory device includes wordlines, which are connected to gates of memory cell transistors; bitlines, which are connected to drains of the memory cell transistors; memory cell capacitors, which are connected to sources of the memory cell transistors; a write boosting signal generation circuit, which generates a write boosting signal in response to a write command, a bitline precharge signal, and a block decoding signal, the block decoding signal selecting a memory cell array including a given memory cell transistor; and capacitors, which are connected between the bitlines and the write boosting signal. The write boosting signal generation circuit may include a PMOS transistor, a source of which is connected to a power supply voltage and a gate of which is connected to the bitline precharge signal; an NMOS transistor, a source of which is connected to a ground voltage, a gate of which is connected to a bitline sensing signal, and a drain of which is connected to a drain of the PMOS transistor; a latch unit, which is connected to the drains of the PMOS transistor and the NMOS transistor; a first NAND gate, which receives an output of the latch unit and the write command; an inverter, which inverts an output of the NAND gate; and a second NAND gate, which is driven by a boosted voltage or an external power supply voltage higher than the power supply voltage, the second NAND gate outputting the write boosting signal in response to an output of the inverter and the block decoding signal. In one embodiment, the memory device further includes: a sense amplification unit, which senses and amplifies a voltage of each of the bitlines; and an isolation transistor, which is located between the bitline and the sense amplification unit, the transistor being gated by a bitline isolation signal. The bitline isolation signal can have a boosted voltage level, when data is written into each of the memory cell capacitors with the write boosting signal inactivated, and can have a power supply voltage level, when data is written into each of the memory cell capacitors with the write boosting signal activated. Therefore, according to the present invention, the amount of electric charge stored in a memory cell capacitor increases because the memory cell capacitor is charged, via a bitline, with a higher voltage level than a power supply voltage level. The memory cell capacitor is charged with a higher voltage level during a write boosting operation that is performed in response to a write boosting signal. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects, features and advantages of the invention will be apparent from the more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. FIG. 1 is a circuit diagram illustrating the structure of a bitline pair of a memory device according to an embodiment of the present invention. FIG. 2 is a circuit diagram illustrating a write boosting signal generation circuit according to an embodiment of the present invention. FIG. 3 is a timing diagram illustrating the operation of the memory device of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a circuit diagram illustrating the structure of a bitline pair of a memory device 100 according to an embodiment of the present invention. Referring to FIG. 1, the memory device 100 includes a memory cell array 110, a bitline isolation unit 120, a sense amplification unit 130, and a bitline capacitor unit 140. In the memory cell array unit 110, memory cells MC0, MC1, MC2, MCn-2, MCn-1, and MCn are arranged at intersection points between a wordline WL0 and a bitline BL, between a wordline WL1 and a complementary bitline /BL, between a wordline WL2 and the complimentary bitline /BL, between a wordline WLn-2 and the bitline BL, between a wordline WLn-1 and the bitline BL, and between a wordline WLn and the complementary bitline /BL, respectively. The bitline isolation unit 120 selectively connects the bitline BL or the complementary bitline /BL to the sense amplification unit 130 via a transistor 121 or 122. The transistors 121 and 122 respond to a bitline isolation signal ISO. The bitline sense amplification unit 130 senses and amplifies memory cell data that is transmitted along the bitline BL or the complementary bitline /BL. The bitline capacitor unit 140 includes capacitors 141 and 142 connected between a write boosting signal WKRi and the bitline BL and between the write boosting signal WKRi and the complementary bitline /BL, respectively. The write boosting signal WKRi is generated by a write boosting signal generation circuit 200 of FIG. 2. Referring to FIG. 2, the write boosting signal generation circuit 200 generates the write boosting signal WKRi in response to a precharge signal /PRECH when a block decoding signal DBRAi, which selects the memory cell array 110 of FIG. 1 during a write command WRITE, is activated. That Is, when the write command WRITE and the block decoding signal DBRAi are activated to a logic high level, the write boosting signal WKRi having an external power supply voltage level EVC or a boosted voltage level VPP is generated when the precharge signal /PRECH has a low logic level. FIG. 3 is a timing diagram illustrating a write operation performed by the memory device 100 of FIG. 1 in conjunction with the write boosting signal generation circuit 200. Referring to FIG. 3, the write operation of the memory device 100, which is divided into a normal write operation and a boosted write operation, is followed by a precharge operation. In the normal write operation, data is written into the memory cells MC0, MC1, MC2, MCn-2, MCn-1, and MCn with a voltage of the bitline BL or a voltage of the complementary bitline /BL, i.e., with a power supply voltage VCC or a ground voltage VSS. The difference between the voltage of the bitline BL and the voltage of the complementary bitline /BL is the same as the difference between the power supply voltage VCC and the ground voltage VSS. The write boosting signal WKRi is set to a ground voltage level VSS when the precharge signal /PRECH is inactivated to a logic high level, a bitline sensing signal /BSENSE is set to a logic high level, the write command is activated to a logic high level, and the block decoding signal DBRAi is activated to a logic high level. The bitline isolation signal ISO with the boosted voltage level VPP is transmitted to the bitline BL and the complementary bitline /BL without dropping the voltage of the transistors 121 and 122. In the boosted write operation, the difference between the voltage of the bitline BL and the voltage of the complementary bitline /BL in the normal write operation is enlarged by ΔV. Then, data is written into the memory cells MC0, MC1, MC2, MCn-2, MCn-1, and MCn with VCC+ΔV or VSS. The write boosting signal WKRi is set to the boosted voltage level VPP or the external power supply voltage level EVC when the precharge signal /PRECH is activated to a logic low level, the bitline sensing signal /BSENSE is set to a logic low level, the write command WRITE is activated to a logic high level, and the block decoding signal DBRAi is activated to a logic high level. The voltage of the bitline isolation signal ISO varies from the boosted voltage level VPP to the power supply voltage level VCC so that the transistors 121 and 122 are selectively turned off. The capacitors 141 and 142 are boosted by the write boosting signal WKRi, i.e., the boosted voltage level VPP or the external power supply voltage level EVC, so that the voltage of the bitline and the complementary bitline /BL is boosted by ΔV. Accordingly, the voltage of the bitline BL amounts to VCC+ΔV, and the transistor 121 is turned off. Thus, data is written into a selected memory cell with VCC+ΔV. The complementary bitlline /BL is boosted to VSS+ΔV. However, the sense amplification unit 130 returns the voltage of the complementary bitline /BL to the ground voltage level VSS using the transistor 122, which is turned on. Therefore, data is written into a selected memory cell with the ground voltage level. In the precharge operation after the write operation, the bitline BL and the complementary bitline /BL are precharged to a precharge voltage VBL for preparing a next read command READ or write command WRITE. The write boosting signal WKRi is maintained at the boosted voltage level VPP or the external power supply voltage level EVC in response to the write command, which is inactivated to a logic low level, and the block decoding signal DBRAI, which is inactivated to a logic low level. The bitline BL or the complementary bitline /BL is disconnected from the sense amplification unit 130 by turning off the transistor 121 or 122, respectively, in response to the bitline isolation signal ISO with the ground voltage level VSS. A precharge circuit (not shown), connected to the bitline BL and the complementary bitline /BL, precharges the bitline BL and the complementary bitline /BL to the precharge voltage VBL. In the boosted write operation of the present invention, a memory cell capacitor is charged with a higher voltage level than a power supply voltage level, i.e., VCC+ΔV, via the bitline BL, and thus the amount of electric charge stored in the memory cell capacitor increases, which results in an increase in the efficiency of sensing memory cell data in a data read operation. While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>This application claims the priority of Korean Patent Application No. 2003-75815, filed on Oct. 29, 2003, in the Korean Intellectual Property Office, the contents of which are incorporated herein in their entirety by reference. 1. Field of the Invention The present invention relates to a semiconductor memory device, and more particularly, to a method of writing data into a memory cell with a boosted bitline voltage, which is higher than a power supply voltage, and a memory device that performs the method. 2. Description of the Related Art A dynamic random access memory (DRAM) includes memory cells, and each of the memory cells is comprised of a transistor and a capacitor. Each of the memory cells, i.e., DRAM cells, stores a logic data value of “1” or “0” according to the amount of electric charge stored in its memory cell capacitor. In general, a data value of 1 is stored in a DRAM cell with a power supply voltage level (VCC), and a data value of 0 is stored in a DRAM cell with a ground voltage level (VSS). Due to the characteristics of a DRAM cell, electric charge leaks from a capacitor of the DRAM cell, and thus a voltage level of data stored in the capacitor of the DRAM cell gradually decreases. Given such electric charge leakage, a data value of 1 is preferably stored with a higher voltage level than the power supply voltage level VCC. Data stored in each DRAM cell is charge-shared between bitlines, and then is sensed and amplified by a bitline sense amplifier. The larger the difference between the amount of electric charge in a cell capacitor holding a data value of 1, and the amount of electric charge of a cell capacitor holding a data value of 0, the higher the efficiency of the bitline sense amplifier sensing data stored in each of the cell capacitors. The amount of electric charge stored in each of the cell capacitors can be increased by increasing the capacitance of each of the cell capacitors. However, since there are numerous restrictions placed on increasing the size of a chip or manufacturing a semiconductor device, there is a clear limit as to the amount by which the capacitance of each of the cell capacitors can be increased. Therefore, in order to achieve a high sensing efficiency with a given amount of electric charge stored in a cell capacitor with a predetermined capacitance, the voltage of bitlines can be increased after the electric charge stored in the cell capacitor is shared between the bitlines, by decreasing capacitance of each of the bitlines. Alternatively, the bitline voltage can be increased during a sensing process by increasing the amount of electric charge stored in the cell capacitor. However, if a data value of 1 is written into a DRAM cell capacitor by charging the DRAM cell capacitor with a higher voltage level than the power supply voltage level (VCC), the amount of electric charge stored in the DRAM cell capacitor increases. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides a method of writing data into a memory cell with a boosted voltage level, which is not lower than a power supply voltage level. The present invention also provides a memory device that performs the method of writing data into a memory cell. According to an aspect of the present invention, there is provided a method of writing data into a memory cell of a memory device. The method includes (a) transmitting data input in response to a write command to a bitline; (b) writing the input data on the bitline into a memory cell capacitor via a memory cell transistor; (c) generating a write boosting signal in response to the write command and a bitline precharge signal; (d) boosting a voltage of a capacitor connected between the write boosting signal and the bitline in response to the write boosting signal; (e) boosting a voltage of the bitline to a predetermined level; and (f) rewriting the input data into the memory cell capacitor with the boosted voltage of the bitline. The write boosting signal can be set to a boosted voltage level or an external power supply voltage level, which is higher than a power supply voltage level of the memory device. In one embodiment, in step (a), the boosted voltage level or the external power supply voltage level is applied to gates of isolation transistors connected between the bitline and a sense amplification unit so that the isolation transistors are turned on. In one embodiment, in step (f), the power supply voltage level of the memory device is applied to the isolation transistors between the bitline and the sense amplification unit. The isolation transistors can be turned off when the input data is at a logic high level. The isolation transistors can be turned on when the input data is at a logic low level, and then the boosted voltage of the bitline can be dropped to a ground voltage level by the sense amplification unit. According to another aspect of the present invention, there is provided a memory device. The memory device includes wordlines, which are connected to gates of memory cell transistors; bitlines, which are connected to drains of the memory cell transistors; memory cell capacitors, which are connected to sources of the memory cell transistors; a write boosting signal generation circuit, which generates a write boosting signal in response to a write command, a bitline precharge signal, and a block decoding signal, the block decoding signal selecting a memory cell array including a given memory cell transistor; and capacitors, which are connected between the bitlines and the write boosting signal. The write boosting signal generation circuit may include a PMOS transistor, a source of which is connected to a power supply voltage and a gate of which is connected to the bitline precharge signal; an NMOS transistor, a source of which is connected to a ground voltage, a gate of which is connected to a bitline sensing signal, and a drain of which is connected to a drain of the PMOS transistor; a latch unit, which is connected to the drains of the PMOS transistor and the NMOS transistor; a first NAND gate, which receives an output of the latch unit and the write command; an inverter, which inverts an output of the NAND gate; and a second NAND gate, which is driven by a boosted voltage or an external power supply voltage higher than the power supply voltage, the second NAND gate outputting the write boosting signal in response to an output of the inverter and the block decoding signal. In one embodiment, the memory device further includes: a sense amplification unit, which senses and amplifies a voltage of each of the bitlines; and an isolation transistor, which is located between the bitline and the sense amplification unit, the transistor being gated by a bitline isolation signal. The bitline isolation signal can have a boosted voltage level, when data is written into each of the memory cell capacitors with the write boosting signal inactivated, and can have a power supply voltage level, when data is written into each of the memory cell capacitors with the write boosting signal activated. Therefore, according to the present invention, the amount of electric charge stored in a memory cell capacitor increases because the memory cell capacitor is charged, via a bitline, with a higher voltage level than a power supply voltage level. The memory cell capacitor is charged with a higher voltage level during a write boosting operation that is performed in response to a write boosting signal. | 20040415 | 20051004 | 20050519 | 82910.0 | 0 | MAI, SON LUU | MEMORY DEVICE AND METHOD FOR WRITING DATA IN MEMORY CELL WITH BOOSTED BITLINE VOLTAGE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,824,874 | ACCEPTED | High performance computing system and method | A High Performance Computing (HPC) node comprises a motherboard, a switch comprising eight or more ports integrated on the motherboard, and at least two processors operable to execute an HPC job, with each processor communicably coupled to the integrated switch and integrated on the motherboard. | 1. A High Performance Computing (HPC) node comprising: a motherboard; a switch comprising eight or more ports, the switch integrated on the motherboard; and at least two processors operable to execute an HPC job, each processor communicably coupled to the integrated switch and integrated on the motherboard. 2. The HPC node of claim 1, each processor coupled to the integrated switch through a Host Channel Adapter (HCA). 3. The HPC node of claim 2, each processor further coupled to the integrated switch through a Hyper Transport/PCI bridge. 4. The HPC node of claim 1, the processors communicably coupled via a Hyper Transport link. 5. The HPC node of claim 1, each processor communicably coupled to the integrated switch through a North Bridge. 6. The HPC node of claim 1, the integrated switch operable to communicate I/O messages at a bandwidth substantially similar to power of the processors. 7. The HPC node of claim 1, the integrated switch comprising an Infiniband switch. 8. The HPC node of claim 1, the integrated switch operable to: communicate a first message from a first of the two or more processors; and communicate a second message from a second of the two or more processors, the first and second message communicated in parallel. 9. A High Performance Computing (HPC) system comprising a plurality of interconnected HPC nodes, each node comprising: a motherboard; a switch comprising eight or more ports, the switch integrated on the motherboard and operable to interconnect at least a subset of the plurality of nodes; and at least two processors operable to execute an HPC job, each processor communicably coupled to the integrated switch and integrated on the motherboard. 10. The HPC system of claim 9, the two or more processors on each node coupled to the integrated switch through a Host Channel Adapter (HCA). 11. The HPC system of claim 10, the two or more processors on each node further coupled to the integrated switch through a Hyper Transport/PCI bridge. 12. The HPC system of claim 9, the two or more processors on each node communicably inter-coupled via a Hyper Transport link. 13. The HPC system of claim 9, the two or more processors on each node communicably coupled to the integrated switch through a North Bridge. 14. The HPC system of claim 9, the integrated switch of each node operable to communicate I/O messages at a bandwidth substantially similar to power of the processors. 15. The HPC system of claim 9, the integrated switch of each node comprising an Infiniband switch. 16. The HPC system of claim 9, the plurality of HPC nodes arranged in a topology, the topology enabled by the integrated fabric of each node. 17. The HPC system of claim 16, the topology comprising a hypercube. 18. The HPC system of claim 16, the topology comprising a folded topology. 19. The HPC system of claim 9, a first node of the plurality of nodes interconnected to a second node of the plurality of nodes along an X axis, a third node of the plurality of nodes along a Y axis, a fourth node of the plurality of nodes along a Z axis, and a fifth node along a diagonal axis. 20. The HPC system of claim 19, the connection between the first node and the fifth node operable to reduce message jumps among the plurality of nodes. 21. A method for forming an HPC node, comprising: providing a motherboard; integrating a switch with the motherboard; integrating at least two processors with the motherboard; and coupling each processor with the integrated switch. 22. The method of claim 21, wherein coupling each processor with the integrated switch comprises coupling each processor to the integrated switch through a Host Channel Adapter (HCA). 23. The method of claim 22, wherein coupling each processor with the integrated switch comprises coupling each processor to the integrated switch through a Hyper Transport/PCI bridge. 24. The method of claim 21, further comprising coupling the processors via a Hyper Transport link. 25. The method of claim 21, wherein coupling each processor with the integrated switch comprises coupling each processor communicably to the integrated switch through a North Bridge. 26. The method of claim 21, the integrated switch operable to communicate I/O messages at a bandwidth substantially similar to power of the processors. 27. The method of claim 21, the integrated switch comprising an Infiniband switch. | TECHNICAL FIELD This disclosure relates generally to the field of data processing and, more specifically, to a high performance computing system and method. BACKGROUND OF THE INVENTION High Performance Computing (HPC) is often characterized by the computing systems used by scientists and engineers for modeling, simulating, and analyzing complex physical or algorithmic phenomena. Currently, HPC machines are typically designed using numerous HPC clusters of one or more processors referred to as nodes. For most large scientific and engineering applications, performance is chiefly determined by parallel scalability and not the speed of individual nodes; therefore, scalability is often a limiting factor in building or purchasing such high performance clusters. Scalability is generally considered to be based on i) hardware, ii) memory, I/O, and communication bandwidth; iii) software; iv) architecture; and v) applications. The processing, memory, and I/O bandwidth in most conventional HPC environments are normally not well balanced and, therefore, do not scale well. Many HPC environments do not have the I/O bandwidth to satisfy high-end data processing requirements or are built with blades that have too many unneeded components installed, which tend to dramatically reduce the system's reliability. Accordingly, many HPC environments may not provide robust cluster management software for efficient operation in production-oriented environments. SUMMARY OF THE INVENTION This disclosure provides a High Performance Computing (HPC) node comprises a motherboard, a switch comprising eight or more ports integrated on the motherboard, and at least two processors operable to execute an HPC job, with each processor communicably coupled to the integrated switch and integrated on the motherboard. The invention has several important technical advantages. For example, one possible advantage of the present invention is that by at least partially reducing, distributing, or eliminating centralized switching functionality, it may provide greater input/output (I/O) performance, perhaps four to eight times the conventional HPC bandwidth. Indeed, in certain embodiments, the I/O performance may nearly equal processor performance. This well-balanced approach may be less sensitive to communications overhead. Accordingly, the present invention may increase blade and overall system performance. A further possible advantage is reduced interconnect latency. Further, the present invention may be more easily scaleable, reliable, and fault tolerant than conventional blades. Yet another advantage may be a reduction of the costs involved in manufacturing an HPC server, which may be passed on to universities and engineering labs, and/or the costs involved in performing HPC processing. The invention may further allow for management software that is more robust and efficient based, at least in part, on the balanced architecture. Various embodiments of the invention may have none, some, or all of these advantages. Other technical advantages of the present invention will be readily apparent to one skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present disclosure and its advantages, reference is now made to the following descriptions, taken in conjunction with the accompanying drawings, in which: FIG. 1 illustrates an example high-performance computing system in accordance with one embodiment of the present disclosure; FIGS. 2A-D illustrate various embodiments of the grid in the system of FIG. 1 and the usage thereof; FIGS. 3A-C illustrate various embodiments of individual nodes in the system of FIGS. 1; FIGS. 4A-B illustrate various embodiments of a graphical user interface in accordance with the system of FIG. 1; FIG. 5 illustrates one embodiment of the cluster management software in accordance with the system in FIG. 1; FIG. 6 is a flowchart illustrating a method for submitting a batch job in accordance with the high-performance computing system of FIG. 1; FIG. 7 is a flowchart illustrating a method for dynamic backfilling of the grid in accordance with the high-performance computing system of FIG. 1; and FIG. 8 is a flow chart illustrating a method for dynamically managing a node failure in accordance with the high-performance computing system of FIG. 1. DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating a high Performance Computing (HPC) system 100 for executing software applications and processes, for example an atmospheric, weather, or crash simulation, using HPC techniques. System 100 provides users with HPC functionality dynamically allocated among various computing nodes 115 with I/O performance substantially similar to the processing performance. Generally, these nodes 115 are easily scaleable because of, among other things, this increased input/output (I/O) performance and reduced fabric latency. For example, the scalability of nodes 115 in a distributed architecture may be represented by a derivative of Amdahl's law: S(N)=1/((FP/N)+FS)*(1−Fc*(1−RR/L)) where S(N)=Speedup on N processors, Fp=Fraction of Parallel Code, Fs=Fraction of Non-Parallel Code, Fc=Fraction of processing devoted to communications, and RR/L=Ratio of Remote/Local Memory Bandwidth. Therefore, by HPC system 100 providing I/O performance substantially equal to or nearing processing performance, HPC system 100 increases overall efficiency of HPC applications and allows for easier system administration. HPC system 100 is a distributed client/server system that allows users (such as scientists and engineers) to submit jobs 150 for processing on an HPC server 102. For example, system 100 may include HPC server 102 that is connected, through network 106, to one or more administration workstations or local clients 120. But system 100 may be a standalone computing environment or any other suitable environment. In short, system 100 is any HPC computing environment that includes highly scaleable nodes 115 and allows the user to submit jobs 150, dynamically allocates scaleable nodes 115 for job 150, and automatically executes job 150 using the allocated nodes 115. Job 150 may be any batch or online job operable to be processed using HPC techniques and submitted by any apt user. For example, job 150 may be a request for a simulation, a model, or for any other high-performance requirement. Job 150 may also be a request to run a data center application, such as a clustered database, an online transaction processing system, or a clustered application server. The term “dynamically,” as used herein, generally means that certain processing is determined, at least in part, at run-time based on one or more variables. The term “automatically,” as used herein, generally means that the appropriate processing is substantially performed by at least part of HPC system 100. It should be understood that “automatically” further contemplates any suitable user or administrator interaction with system 100 without departing from the scope of this disclosure. HPC server 102 comprises any local or remote computer operable to process job 150 using a plurality of balanced nodes 115 and cluster management engine 130. Generally, HPC server 102 comprises a distributed computer such as a blade server or other distributed server. However the configuration, server 102 includes a plurality of nodes 115. Nodes 115 comprise any computer or processing device such as, for example, blades, general-purpose personal computers (PC), Macintoshes, workstations, Unix-based computers, or any other suitable devices. Generally, FIG. 1 provides merely one example of computers that may be used with the disclosure. For example, although FIG. 1 illustrates one server 102 that may be used with the disclosure, system 100 can be implemented using computers other than servers, as well as a server pool. In other words, the present disclosure contemplates computers other than general purpose computers as well as computers without conventional operating systems. As used in this document, the term “computer” is intended to encompass a personal computer, workstation, network computer, or any other suitable processing device. HPC server 102, or the component nodes 115, may be adapted to execute any operating system including Linux, UNIX, Windows Server, or any other suitable operating system. According to one embodiment, HPC server 102 may also include or be communicably coupled with a remote web server. Therefore, server 102 may comprise any computer with software and/or hardware in any combination suitable to dynamically allocate nodes 115 to process HPC job 150. At a high level, HPC server 102 includes a management node 105, a grid 110 comprising a plurality of nodes 115, and cluster management engine 130. More specifically, server 102 may be a standard 19″ rack including a plurality of blades (nodes 115) with some or all of the following components: i) dual-processors; ii) large, high bandwidth memory; iii) dual host channel adapters (HCAs); iv) integrated fabric switching; v) FPGA support; and vi) redundant power inputs or N+1 power supplies. These various components allow for failures to be confined to the node level. But it will be understood that HPC server 102 and nodes 115 may not include all of these components. Management node 105 comprises at least one blade substantially dedicated to managing or assisting an administrator. For example, management node 105 may comprise two blades, with one of the two blades being redundant (such as an active/passive configuration). In one embodiment, management node 105 may be the same type of blade or computing device as HPC nodes 115. But, management node 105 may be any node, including any number of circuits and configured in any suitable fashion, so long as it remains operable to at least partially manage grid 110. Often, management node 105 is physically or logically separated from the plurality of HPC nodes 115, jointly represented in grid 110. In the illustrated embodiment, management node 105 may be communicably coupled to grid 110 via link 108. Link 108 may comprise any communication conduit implementing any appropriate communications protocol. In one embodiment, link 108 provides Gigabit or 10 Gigabit Ethernet communications between management node 105 and grid 110. Grid 110 is a group of nodes 115 interconnected for increased processing power. Typically, grid 110 is a 3D Torus, but it may be a mesh, a hypercube, or any other shape or configuration without departing from the scope of this disclosure. The links between nodes 115 in grid 110 may be serial or parallel analog links, digital links, or any other type of link that can convey electrical or electromagnetic signals such as, for example, fiber or copper. Each node 115 is configured with an integrated switch. This allows node 115 to more easily be the basic construct for the 3D Torus and helps minimize XYZ distances between other nodes 115. Further, this may make copper wiring work in larger systems at up to Gigabit rates with, in some embodiments, the longest cable being less than 5 meters. In short, node 115 is generally optimized for nearest-neighbor communications and increased I/O bandwidth. Each node 115 may include a cluster agent 132 communicably coupled with cluster management engine 130. Generally, agent 132 receives requests or commands from management node 105 and/or cluster management engine 130. Agent 132 could include any hardware, software, firmware, or combination thereof operable to determine the physical status of node 115 and communicate the processed data, such as through a “heartbeat,” to management node 105. In another embodiment, management node 105 may periodically poll agent 132 to determine the status of the associated node 115. Agent 132 may be written in any appropriate computer language such as, for example, C, C++, Assembler, Java, Visual Basic, and others or any combination thereof so long as it remains compatible with at least a portion of cluster management engine 130. Cluster management engine 130 could include any hardware, software, firmware, or combination thereof operable to dynamically allocate and manage nodes 115 and execute job 150 using nodes 115. For example, cluster management engine 130 may be written or described in any appropriate computer language including C, C++, Java, Visual Basic, assembler, any suitable version of 4GL, and others or any combination thereof. It will be understood that while cluster management engine 130 is illustrated in FIG. 1 as a single multi-tasked module, the features and functionality performed by this engine may be performed by multiple modules such as, for example, a physical layer module, a virtual layer module, a job scheduler, and a presentation engine (as shown in more detail in FIG. 5). Further, while illustrated as external to management node 105, management node 105 typically executes one or more processes associated with cluster management engine 130 and may store cluster management engine 130. Moreover, cluster management engine 130 may be a child or sub-module of another software module without departing from the scope of this disclosure. Therefore, cluster management engine 130 comprises one or more software modules operable to intelligently manage nodes 115 and jobs 150. Server 102 may include interface 104 for communicating with other computer systems, such as client 120, over network 106 in a client-server or other distributed environment. In certain embodiments, server 102 receives jobs 150 or job policies from network 106 for storage in disk farm 140. Disk farm 140 may also be attached directly to the computational array using the same wideband interfaces that interconnects the nodes. Generally, interface 104 comprises logic encoded in software and/or hardware in a suitable combination and operable to communicate with network 106. More specifically, interface 104 may comprise software supporting one or more communications protocols associated with communications network 106 or hardware operable to communicate physical signals. Network 106 facilitates wireless or wireline communication between computer server 102 and any other computer, such as clients 120. Indeed, while illustrated as residing between server 102 and client 120, network 106 may also reside between various nodes 115 without departing from the scope of the disclosure. In other words, network 106 encompasses any network, networks, or sub-network operable to facilitate communications between various computing components. Network 106 may communicate, for example, Internet Protocol (IP) packets, Frame Relay frames, Asynchronous Transfer Mode (ATM) cells, voice, video, data, and other suitable information between network addresses. Network 106 may include one or more local area networks (LANs), radio access networks (RANs), metropolitan area networks (MANs), wide area networks (WANs) , all or a portion of the global computer network known as the Internet, and/or any other communication system or systems at one or more locations. In general, disk farm 140 is any memory, database or storage area network (SAN) for storing jobs 150, profiles, boot images, or other HPC information. According to the illustrated embodiment, disk farm 140 includes one or more storage clients 142. Disk farm 140 may process and route data packets according to any of a number of communication protocols, for example, InfiniBand (IB), Gigabit Ethernet (GE), or FibreChannel (FC). Data packets are typically used to transport data within disk farm 140. A data packet may include a header that has a source identifier and a destination identifier. The source identifier, for example, a source address, identifies the transmitter of information, and the destination identifier, for example, a destination address, identifies the recipient of the information. Client 120 is any device operable to present the user with a job submission screen or administration via a graphical user interface (GUI) 126. At a high level, illustrated client 120 includes at least GUI 126 and comprises an electronic computing device operable to receive, transmit, process and store any appropriate data associated with system 100. It will be understood that there may be any number of clients 120 communicably coupled to server 102. Further, “client 120” and “user of client 120” may be used interchangeably as appropriate without departing from the scope of this disclosure. Moreover, for ease of illustration, each client is described in terms of being used by one user. But this disclosure contemplates that many users may use one computer to communicate jobs 150 using the same GUI 126. As used in this disclosure, client 120 is intended to encompass a personal computer, touch screen terminal, workstation, network computer, kiosk, wireless data port, cell phone, personal data assistant (PDA) , one or more processors within these or other devices, or any other suitable processing device. For example, client 120 may comprise a computer that includes an input device, such as a keypad, touch screen, mouse, or other device that can accept information, and an output device that conveys information associated with the operation of server 102 or clients 120, including digital data, visual information, or GUI 126. Both the input device and output device may include fixed or removable storage media such as a magnetic computer disk, CD-ROM, or other suitable media to both receive input from and provide output to users of clients 120 through the administration and job submission display, namely GUI 126. GUI 126 comprises a graphical user interface operable to allow i) the user of client 120 to interface with system 100 to submit one or more jobs 150; and/or ii) the system (or network) administrator using client 120 to interface with system 100 for any suitable supervisory purpose. Generally, GUI 126 provides the user of client 120 with an efficient and user-friendly presentation of data provided by HPC system 100. GUI 126 may comprise a plurality of customizable frames or views having interactive fields, pull-down lists, and buttons operated by the user. In one embodiment, GUI 126 presents a job submission display that presents the various job parameter fields and receives commands from the user of client 120 via one of the input devices. GUI 126 may, alternatively or in combination, present the physical and logical status of nodes 115 to the system administrator, as illustrated in FIGS. 4A-B, and receive various commands from the administrator. Administrator commands may include marking nodes as (un)available, shutting down nodes for maintenance, rebooting nodes, or any other suitable command. Moreover, it should be understood that the term graphical user interface may be used in the singular or in the plural to describe one or more graphical user interfaces and each of the displays of a particular graphical user interface. Therefore, GUI 126 contemplates any graphical user interface, such as a generic web browser, that processes information in system 100 and efficiently presents the results to the user. Server 102 can accept data from client 120 via the web browser (e.g., Microsoft Internet Explorer or Netscape Navigator) and return the appropriate HTML or XML responses using network 106. In one aspect of operation, HPC server 102 is first initialized or booted. During this process, cluster management engine 130 determines the existence, state, location, and/or other characteristics of nodes 115 in grid 110. As described above, this may be based on a “heartbeat” communicated upon each node's initialization or upon near immediate polling by management node 105. Next, cluster management engine 130 may dynamically allocate various portions of grid 110 to one or more virtual clusters 220 based on, for example, predetermined policies. In one embodiment, cluster management engine 130 continuously monitors nodes 115 for possible failure and, upon determining that one of the nodes 115 failed, effectively managing the failure using any of a variety of recovery techniques. Cluster management engine 130 may also manage and provide a unique execution environment for each allocated node of virtual cluster 220. The execution environment may consist of the hostname, IP address, operating system, configured services, local and shared file systems, and a set of installed applications and data. The cluster management engine 130 may dynamically add or subtract nodes from virtual cluster 220 according to associated policies and according to inter-cluster policies, such as priority. When a user logs on to client 120, he may be presented with a job submission screen via GUI 126. Once the user has entered the job parameters and submitted job 150, cluster management engine 130 processes the job submission, the related parameters, and any predetermined policies associated with job 150, the user, or the user group. Cluster management engine 130 then determines the appropriate virtual cluster 220 based, at least in part, on this information. Engine 130 then dynamically allocates a job space 230 within virtual cluster 220 and executes job 150 across the allocated nodes 115 using HPC techniques. Based, at least in part, on the increased I/O performance, HPC server 102 may more quickly complete processing of job 150. Upon completion, cluster management engine communicates results 160 to the user. FIGS. 2A-D illustrate various embodiments of grid 210 in system 100 and the usage or topology thereof. FIG. 2A illustrates one configuration, namely a 3D Torus, of grid 210 using a plurality of node types. For example, the illustrated node types are external I/O node, FS server, FS metadata server, database server, and compute node. FIG. 2B illustrates an example of “folding” of grid 210. Folding generally allows for one physical edge of grid 215 to connect to a corresponding axial edge, thereby providing a more robust or edgeless topology. In this embodiment, nodes 215 are wrapped around to provide a near seamless topology connect by node link 216. Node line 216 may be any suitable hardware implementing any communications protocol for interconnecting two or more nodes 215. For example, node line 216 may be copper wire or fiber optic cable implementing Gigabit Ethernet. FIG. 2C illustrates grid 210 with one virtual cluster 220 allocated within it. While illustrated with only one virtual cluster 220, there may be any number (including zero) of virtual clusters 220 in grid 210 without departing from the scope of this disclosure. Virtual cluster 220 is a logical grouping of nodes 215 for processing related jobs 150. For example, virtual cluster 220 may be associated with one research group, a department, a lab, or any other group of users likely to submit similar jobs 150. Virtual cluster 220 may be any shape and include any number of nodes 215 within grid 210. Indeed, while illustrated virtual cluster 220 includes a plurality of physically neighboring nodes 215, cluster 220 may be a distributed cluster of logically related nodes 215 operable to process job 150. Virtual cluster 220 may be allocated at any appropriate time. For example, cluster 220 may be allocated upon initialization of system 100 based, for example, on startup parameters or may be dynamically allocated based, for example, on changed server 102 needs. Moreover, virtual cluster 220 may change its shape and size over time to quickly respond to changing requests, demands, and situations. For example, virtual cluster 220 may be dynamically changed to include an automatically allocated first node 215 in response to a failure of a second node 215, previously part of cluster 220. In certain embodiments, clusters 220 may share nodes 215 as processing requires. FIG. 2D illustrates various job spaces, 230a and 230b respectively, allocated within example virtual cluster 220. Generally, job space 230 is a set of nodes 215 within virtual cluster 220 dynamically allocated to complete received job 150. Typically, there is one job space 230 per executing job 150 and vice versa, but job spaces 230 may share nodes 215 without departing from the scope of the disclosure. The dimensions of job space 230 may be manually input by the user or administrator or dynamically determined based on job parameters, policies, and/or any other suitable characteristic. FIGS. 3A-C illustrate various embodiments of individual nodes 115 in grid 110. In the illustrated, but example, embodiments, nodes 115 are represented by blades 315. Blade 315 comprises any computing device in any orientation operable to process all or a portion, such as a thread or process, of job 150. For example, blade 315 may be a standard Xeon64™ motherboard, a standard PCI-Express Opteron™ motherboard, or any other suitable computing card. Blade 315 is an integrated fabric architecture that distributes the fabric switching components uniformly across nodes 115 in grid 110, thereby possibly reducing or eliminating any centralized switching function, increasing the fault tolerance, and allowing message passing in parallel. More specifically, blade 315 includes an integrated switch 345. Switch 345 includes any number of ports that may allow for different topologies. For example, switch 345 may be an eight-port switch that enables a tighter three-dimensional mesh or 3D Torus topology. These eight ports include two “X” connections for linking to neighbor nodes 115 along an X-axis, two “Y” connections for linking to neighbor nodes 115 along a Y-axis, two “Z” connections for linking to neighbor nodes 115 along a Z-axis, and two connections for linking to management node 105. In one embodiment, switch 345 may be a standard eight port Infiniband-4x switch IC, thereby easily providing built-in fabric switching. Switch 345 may also comprise a twenty-four port switch that allows for multidimensional topologies, such a 4-D Torus, or other non-traditional topologies of greater than three dimensions. Moreover, nodes 115 may further interconnected along a diagonal axis, thereby reducing jumps or hops of communications between relatively distant nodes 115. For example, a first node 115 may be connected with a second node 115 that physically resides along a northeasterly axis several three dimensional “jumps” away. FIG. 3A illustrates a blade 315 that, at a high level, includes at least two processors 320a and 320b, local or remote memory 340, and integrated switch (or fabric) 345. Processor 320 executes instructions and manipulates data to perform the operations of blade 315 such as, for example, a central processing unit (CPU). Reference to processor 320 is meant to include multiple processors 320 where applicable. In one embodiment, processor 320 may comprise a Xeon64 or Itanium™ processor or other similar processor or derivative thereof. For example, the Xeon64 processor may be a 3.4 GHz chip with a 2 MB Cache and HyperTreading. In this embodiment, the dual processor module may include a native PCI/Express that improves efficiency. Accordingly, processor 320 has efficient memory bandwidth and, typically, has the memory controller built into the processor chip. Blade 315 may also include Northbridge 321, Southbridge 322, PCI channel 325, HCA 335, and memory 340. Northbridge 321 communicates with processor 320 and controls communications with memory 340, a PCI bus, Level 2 cache, and any other related components. In one embodiment, Northbridge 321 communicates with processor 320 using the frontside bus (FSB). Southbridge 322 manages many of the input/output (I/O) functions of blade 315. In another embodiment, blade 315 may implement the Intel Hub Architecture (IHATM), which includes a Graphics and AGP Memory Controller Hub (GMCH) and an I/O Controller Hub (ICH). PCI channel 325 comprises any high-speed, low latency link designed to increase the communication speed between integrated components. This helps reduce the number of buses in blade 315, which can reduce system bottlenecks. HCA 335 comprises any component providing channel-based I/O within server 102. Each HCA 335 may provide a total bandwidth of 2.65 GB/sec, thereby allowing 1.85 GB/sec per PE to switch 345 and 800 MB/sec per PE to I/O such as, for example, BIOS (Basic Input/Output System), an Ethernet management interface, and others. This further allows the total switch 345 bandwidth to be 3.7 GB/sec for 13.6 Gigaflops/sec peak or 0.27 Bytes/Flop I/O rate is 50 MB/sec per Gigaflop. Memory 340 includes any memory or database module and may take the form of volatile or non-volatile memory including, without limitation, magnetic media, optical media, flash memory, random access memory (RAM), read-only memory (ROM), removable media, or any other suitable local or remote memory component. In the illustrated embodiment, memory 340 is comprised of 8 GB of dual double data rate (DDR) memory components operating at least 6.4 GB/s. Memory 340 may include any appropriate data for managing or executing HPC jobs 150 without departing from this disclosure. FIG. 3B illustrates a blade 315 that includes two processors 320a and 320b, memory 340, HyperTransport/peripheral component interconnect (HT/PCI) bridges 330a and 330b, and two HCAs 335a and 335b. Example blade 315 includes at least two processors 320. Processor 320 executes instructions and manipulates data to perform the-operations of blade 315 such as, for example, a central processing unit (CPU). In the illustrated embodiment, processor 320 may comprise an Opteron processor or other similar processor or derivative. In this embodiment, the Opteron processor design supports the development of a well balanced building block for grid 110. Regardless, the dual processor module may provide four to five Gigaflop usable performance and the next generation technology helps solve memory bandwidth limitation. But blade 315 may more than two processors 320 without departing from the scope of this disclosure. Accordingly, processor 320 has efficient memory bandwidth and, typically, has the memory controller built into the processor chip. In this embodiment, each processor 320 has one or more HyperTransport™ (or other similar conduit type) links 325. Generally, HT link 325 comprises any high-speed, low latency link designed to increase the communication speed between integrated components. This helps reduce the number of buses in blade 315, which can reduce system bottlenecks. HT link 325 supports processor to processor communications for cache coherent multiprocessor blades 315. Using HT links 325, up to eight processors 320 may be placed on blade 315. If utilized, HyperTransport may provide bandwidth of 6.4 GB/sec, 12.8, or more, thereby providing a better than forty-fold increase in data throughput over legacy PCI buses. Further HyperTransport technology may be compatible with legacy I/O standards, such as PCI, and other technologies, such as PCI-X. Blade 315 further includes HT/PCI bridge 330 and HCA 335. PCI bridge 330 may be designed in compliance with PCI Local Bus Specification Revision 2.2 or 3.0 or PCI Express Base Specification 1.0a or any derivatives thereof. HCA 335 comprises any component providing channel-based I/O within server 102. In one embodiment, HCA 335 comprises an Infiniband HCA. InfiniBand channels are typically created by attaching host channel adapters and target channel adapters, which enable remote storage and network connectivity into an InfiniBand fabric, illustrated in more detail in FIG. 3B. Hypertransport 325 to PCI-Express Bridge 330 and HCA 335 may create a full-duplex 2 GB/sec I/O channel for each processor 320. In certain embodiments, this provides sufficient bandwidth to support processor-processor communications in distributed HPC environment 100. Further, this provides blade 315 with I/O performance nearly or substantially balanced with the performance of processors 320. FIG. 3C illustrates another embodiment of blade 315 including a daughter board. In this embodiment, the daughter board may support 3.2 GB/sec or higher cache coherent interfaces. The daughter board is operable to include one or more Field Programmable Gate Arrays (FPGAs) 350. For example, the illustrated daughter board includes two FPGAs 350, represented by 350a and 350b, respectively. Generally, FPGA 350 provides blade 315 with non-standard interfaces, the ability to process custom algorithms, vector processors for signal, image, or encryption/decryption processing applications, and high bandwidth. For example, FPGA may supplement the ability of blade 315 by providing acceleration factors of ten to twenty times the performance of a general purpose processor for special functions such as, for example, low precision Fast Fourier Transform (FFT) and matrix arithmetic functions. The preceding illustrations and accompanying descriptions provide exemplary diagrams for implementing various scaleable nodes 115 (illustrated as example blades 315). However, these figures are merely illustrative and system 100 contemplates using any suitable combination and arrangement of elements for implementing various scalability schemes. Although the present invention has been illustrated and described, in part, in regard to blade server 102, those of ordinary skill in the art will recognize that the teachings of the present invention may be applied to any clustered HPC server environment. Accordingly, such clustered servers 102 that incorporate the techniques described herein may be local or a distributed without departing from the scope of this disclosure. Thus, these servers 102 may include HPC modules (or nodes 115) incorporating any suitable combination and arrangement of elements for providing high performance computing power, while reducing I/O latency. Moreover, the operations of the various illustrated HPC modules may be combined and/or separated as appropriate. For example, grid 110 may include a plurality of substantially similar nodes 115 or various nodes 115 implementing differing hardware or fabric architecture. FIGS. 4A-B illustrate various embodiments of a management graphical user interface 400 in accordance with the system 100. Often, management GUI 400 is presented to client 120 using GUI 126. In general, management GUI 400 presents a variety of management interactive screens or displays to a system administrator and/or a variety of job submission or profile screens to a user. These screens or displays are comprised of graphical elements assembled into various views of collected information. For example, GUI 400 may present a display of the physical health of grid 110 (illustrated in FIG. 4A) or the logical allocation or topology of nodes 115 in grid 110 (illustrated in FIG. 4B). FIG. 4A illustrates example display 400a. Display 400a may include information presented to the administrator for effectively managing nodes 115. The illustrated embodiment includes a standard web browser with a logical “picture” or screenshot of grid 110. For example, this picture may provide the physical status of grid 110 and the component nodes 115. Each node 115 may be one of any number of colors, with each color representing various states. For example, a failed node 115 may be red, a utilized or allocated node 115 may be black, and an unallocated node 115 may be shaded. Further, display 400a may allow the administrator to move the pointer over one of the nodes 115 and view the various physical attributes of it. For example, the administrator may be presented with information including “node,” “availability,” “processor utilization,” “memory utilization,” “temperature,” “physical location,” and “address.” Of course, these are merely example data fields and any appropriate physical or logical node information may be display for the administrator. Display 400a may also allow the administrator to rotate the view of grid 110 or perform any other suitable function. FIG. 4B illustrates example display 400b. Display 400b presents a view or picture of the logical state of grid 100. The illustrated embodiment presents the virtual cluster 220 allocated within grid 110. Display 400b further displays two example job spaces 230 allocate within cluster 220 for executing one or more jobs 150. Display 400b may allow the administrator to move the pointer over graphical virtual cluster 220 to view the number of nodes 115 grouped by various statuses (such as allocated or unallocated) . Further, the administrator may move the pointer over one of the job spaces 230 such that suitable job information is presented. For example, the administrator may be able to view the job name, start time, number of nodes, estimated end time, processor usage, I/O usage, and others. It will be understood that management GUI 126 (represented above by example displays 400a and 400b, respectively) is for illustration purposes only and may include none, some, or all of the illustrated graphical elements as well as additional management elements not shown. FIG. 5 illustrates one embodiment of cluster management engine 130, shown here as engine 500, in accordance with system 100. In this embodiment, cluster management engine 500 includes a plurality of sub-modules or components: physical manager 505, virtual manager 510, job scheduler 515, and local memory or variables 520. Physical manager 505 is any software, logic, firmware, or other module operable to determine the physical health of various nodes 115 and effectively manage nodes 115 based on this determined health. Physical manager may use this data to efficiently determine and respond to node 115 failures. In one embodiment, physical manager 505 is communicably coupled to a plurality of agents 132, each residing on one node 115. As described above, agents 132 gather and communicate at least physical information to manager 505. Physical manager 505 may be further operable to communicate alerts to a system administrator at client 120 via network 106. Virtual manager 510 is any software, logic, firmware, or other module operable to manage virtual clusters 220 and the logical state of nodes 115. Generally, virtual manager 510 links a logical representation of node 115 with the physical status of node 115. Based on these links, virtual manager 510 may generate virtual clusters 220 and process various changes to these clusters 220, such as in response to node failure or a (system or user) request for increased HPC processing. Virtual manager 510 may also communicate the status of virtual cluster 220, such as unallocated nodes 115, to job scheduler 515 to enable dynamic backfilling of unexecuted, or queued, HPC processes and jobs 150. Virtual manager 510 may further determine the compatibility of job 150 with particular nodes 115 and communicate this information to job scheduler 515. In certain embodiments, virtual manager 510 may be an object representing an individual virtual cluster 220. Cluster management engine 500 may also include job scheduler 515. Job scheduler sub-module 515 is a topology-aware module that processes aspects of the system's resources, as well with the processors and the time allocations, to determine an optimum job space 230 and time. Factors that are often considered include processors, processes, memory, interconnects, disks, visualization engines, and others. In other words, job scheduler 515 typically interacts with GUI 126 to receive jobs 150, physical manager 505 to ensure the health of various nodes 115, and virtual manager 510 to dynamically allocate job space 230 within a certain virtual cluster 220. This dynamic allocation is accomplished through various algorithms that often incorporates knowledge of the current topology of grid 110 and, when appropriate, virtual cluster 220. Job scheduler 515 handles both batch and interactive execution of both serial and parallel programs. Scheduler 515 should also provide a way to implement policies 524 on selecting and executing various problems presented by job 150. Cluster management engine 500, such as through job scheduler 515, may be further operable to perform efficient check-pointing. Restart dumps typically comprise over seventy-five percent of data written to disk. This I/O is often done so that processing is not lost to a platform failure. Based on this, a file system's I/O can be segregated into two portions: productive I/O and defensive I/O. Productive I/O is the writing of data that the user calls for to do science such as, for example, visualization dumps, traces of key physics variables over time, and others. Defensive I/O is performed to manage a large simulation run over a substantial period of time. Accordingly, increased I/O bandwidth greatly reduces the time and risk involved in check-pointing. Returning to engine 500, local memory 520 comprises logical descriptions (or data structures) of a plurality of features of system 100. Local memory 520 may be stored in any physical or logical data storage operable to be defined, processed, or retrieved by compatible code. For example, local memory 520 may comprise one or more extensible Markup Language (XML) tables or documents. The various elements may be described in terms of SQL statements or scripts, Virtual Storage Access Method (VSAM) files, flat files, binary data files, Btrieve files, database files, or comma-separated-value (CSV) files. It will be understood that each element may comprise a variable, table, or any other suitable data structure. Local memory 520 may also comprise a plurality of tables or files stored on one server 102 or across a plurality of servers or nodes. Moreover, while illustrated as residing inside engine 500, some or all of local memory 520 may be internal or external without departing from the scope of this disclosure. Illustrated local memory 520 includes physical list 521, virtual list 522, group file 523, policy table 524, and job queue 525. But, while not illustrated, local memory 520 may include other data structures, including a job table and audit log, without departing from the scope of this disclosure. Returning to the illustrated structures, physical list 521 is operable to store identifying and physical management information about node 115. Physical list 521 may be a multi-dimensional data structure that includes at least one record per node 115. For example, the physical record may include fields such as “node,” “availability,” “processor utilization,” “memory utilization,” “temperature,” “physical location,” “address,” “boot images,” and others. It will be understood that each record may include none, some, or all of the example fields. In one embodiment, the physical record may provide a foreign key to another table, such as, for example, virtual list 522. Virtual list 522 is operable to store logical or virtual management information about node 115. Virtual list 522 may be a multi-dimensional data structure that includes at least one record per node 115. For example, the virtual record may include fields such as “node,” “availability,” “job,” “virtual cluster,” “secondary node,” “logical location,” “compatibility,” and others. It will be understood that each record may include none, some, or all of the example fields. In one embodiment, the virtual record may include a link to another table such as, for example, group file 523. Group file 523 comprises one or more tables or records operable to store user group and security information, such as access control lists (or ACLs). For example, each group record may include a list of available services, nodes 115, or jobs for a user. Each logical group may be associated with a business group or unit, a department, a project, a security group, or any other collection of one or more users that are able to submit jobs 150 or administer at least part of system 100. Based on this information, cluster management engine 500 may determine if the user submitting job 150 is a valid user and, if so, the optimum parameters for job execution. Further, group table 523 may associate each user group with a virtual cluster 220 or with one or more physical nodes 115, such as nodes residing within a particular group's domain. This allows each group to have an individual processing space without competing for resources. However, as described above, the shape and size of virtual cluster 220 may be dynamic and may change according to needs, time, or any other parameter. Policy table 524 includes one or more policies. It will be understood that policy table 524 and policy 524 may be used interchangeably as appropriate. Policy 524 generally stores processing and management information about jobs 150 and/or virtual clusters 220. For example, policies 524 may include any number of parameters or variables including problem size, problem run time, timeslots, preemption, users' allocated share of node 115 or virtual cluster 220, and such. Job queue 525 represents one or more streams of jobs 150 awaiting execution. Generally, queue 525 comprises any suitable data structure, such as a bubble array, database table, or pointer array, for storing any number (including zero) of jobs 150 or reference thereto. There may be one queue 525 associated with grid 110 or a plurality of queues 525, with each queue 525 associated with one of the unique virtual clusters 220 within grid 110. In one aspect of operation, cluster management engine 500 receives job 150, made up of N tasks which cooperatively solve a problem by performing calculations and exchanging information. Cluster management engine 500 allocates N nodes 115 and assigns each of the N tasks to one particular node 515 using any suitable technique, thereby allowing the problem to be solved efficiently. For example, cluster management engine 500 may utilize job parameters, such as job task placement strategy, supplied by the user. Regardless, cluster management engine 500 attempts to exploit the architecture of server 102, which in turn provides the quicker turnaround for the user and likely improves the overall throughput for system 100. In one embodiment, cluster management engine 500 then selects and allocates nodes 115 according to any of the following example topologies: Specified 2D (x,y) or 3D (x,y,z)—Nodes 115 are allocated and tasks may be ordered in the specified dimensions, thereby preserving efficient neighbor to neighbor communication. The specified topology manages a variety of jobs 150 where it is desirable that the physical communication topology match the problem topology allowing the cooperating tasks of job 150 to communicate frequently with neighbor tasks. For example, a request of 8 tasks in a 2×2×2 dimension (2, 2, 2) will be allocated in a cube. For best-fit purposes, 2D allocations can be “folded” into 3 dimensions (as discussed in FIG. 2D), while preserving efficient neighbor to neighbor communications. Cluster management engine 500 may be free to allocate the specified dimensional shape in any orientation. For example, a 2×2×8 box may be allocated within the available physical nodes vertically or horizontally Best Fit Cube—cluster management engine 500 allocates N nodes 115 in a cubic volume. This topology efficiently handles jobs 150 allowing cooperating tasks to exchange data with any other tasks by minimizing the distance between any two nodes 115. Best Fit Sphere—cluster management engine 500 allocates N nodes 115 in a spherical volume. For example, the first task may be placed in the center node 115 of the sphere with the rest of the tasks placed on nodes 115 surrounding the center node 115. It will be understood that the placement order of the remaining tasks is not typically critical. This topology may minimize the distance between the first task and all other tasks. This efficiently handles a large class of problems where tasks 2-N communicate with the first task, but not with each other. Random—cluster management engine 500 allocates N nodes 115 with reduced consideration for where nodes 115 are logically or physically located. In one embodiment, this topology encourages aggressive use of grid 110 for backfilling purposes, with little impact to other jobs 150. It will be understood that the prior topologies and accompanying description are for illustration purposes only and may not depict actual topologies used or techniques for allocating such topologies. Cluster management engine 500 may utilize a placement weight, stored as a job 150 parameter or policy 524 parameter. In one embodiment, the placement weight is a modifier value between 0 and 1, which represents how aggressively cluster management engine 500 should attempt to place nodes 115 according to the requested task (or process) placement strategy. In this example, a value of 0 represents placing nodes 115 only if the optimum strategy (or dimensions) is possible and a value of 1 represents placing nodes 115 immediately, as long as there are enough free or otherwise available nodes 115 to handle the request. Typically, the placement weight does not override administrative policies 524 such as resource reservation, in order to prevent starvation of large jobs 150 and preserve the job throughput of HPC system 100. The preceding illustration and accompanying description provide an exemplary modular diagram for engine 500 implementing logical schemes for managing nodes 115 and jobs 150. However, this figure is merely illustrative and system 100 contemplates using any suitable combination and arrangement of logical elements for implementing these and other algorithms. Thus, these software modules may include any suitable combination and arrangement of elements for effectively managing nodes 115 and jobs 150. Moreover, the operations of the various illustrated modules may be combined and/or separated as appropriate. FIG. 6 is a flowchart illustrating an example method 600 for dynamically processing a job submission in accordance with one embodiment of the present disclosure. Generally, FIG. 6 describes method 600, which receives a batch job submission, dynamically allocates nodes 115 into a job space 230 based on the job parameters and associated policies 524, and executes job 150 using the allocated space. The following description focuses on the operation of cluster management module 130 in performing method 600. But system 100 contemplates using any appropriate combination and arrangement of logical elements implementing some or all of the described functionality, so long as the functionality remains appropriate. Method 600 begins at step 605, where HPC server 102 receives job submission 150 from a user. As described above, in one embodiment the user may submit job 150 using client 120. In another embodiment, the user may submit job 150 directly using HPC server 102. Next, at step 610, cluster management engine 130 selects group 523 based upon the user. Once the user is verified, cluster management engine 130 compares the user to the group access control list (ACL) at step 615. But it will be understood that cluster management engine 130 may use any appropriate security technique to verify the user. Based upon determined group 523, cluster management engine 130 determines if the user has access to the requested service. Based on the requested service and hostname, cluster management engine 130 selects virtual cluster 220 at step 620. Typically., virtual cluster 220 may be identified and allocated prior to the submission of job 150. But, in the event virtual cluster 220 has not been established, cluster management engine 130 may automatically allocate virtual cluster 220 using any of the techniques described above. Next, at step 625, cluster management engine 130 retrieves policy 524 based on the submission of job 150. In one embodiment, cluster management engine 130 may determine the appropriate policy 524 associated with the user, job 150, or any other appropriate criteria. Cluster management engine 130 then determines or otherwise calculates the dimensions of job 150 at step 630. It will be understood that the appropriate dimensions may include length, width, height, or any other appropriate parameter or characteristic. As described above, these dimensions are used to determine the appropriate job space 230 (or subset of nodes 115) within virtual cluster 220. After the initial parameters have been established, cluster management 130 attempts to execute job 150 on HPC server 102 in steps 635 through 665. At decisional step 635, cluster management engine 130 determines if there are enough available nodes to allocate the desired job space 230, using the parameters already established. If there are not enough nodes 115, then cluster management engine 130 determines the earliest available subset 230 of nodes 115 in virtual cluster 220 at step 640. Then, cluster management engine 130 adds job 150 to job queue 125 until the subset 230 is available at step 645. Processing then returns to decisional step 635. Once there are enough nodes 115 available, then cluster management engine 130 dynamically determines the optimum subset 230 from available nodes 115 at step 650. It will be understood that the optimum subset 230 may be determined using any appropriate criteria, including fastest processing time, most reliable nodes 115, physical or virtual locations, or first available nodes 115. At step 655, cluster management engine 130 selects the determined subset 230 from the selected virtual cluster 220. Next, at step 660, cluster management engine 130 allocates the selected nodes 115 for job 150 using the selected subset 230. According to one embodiment, cluster management engine 130 may change the status of nodes 115 in virtual node list 522 from “unallocated” to “allocated”. Once subset 230 has been appropriately allocated, cluster management engine 130 executes job 150 at step 665 using the allocated space based on the job parameters, retrieved policy 524, and any other suitable parameters. At any appropriate time, cluster management engine 130 may communicate or otherwise present job results 160 to the user. For example, results 160 may be formatted and presented to the user via GUI 126. FIG. 7 is a flowchart illustrating an example method 700 for dynamically backfilling a virtual cluster 220 in grid 110 in accordance with one embodiment of the present disclosure. At a high level, method 700 describes determining available space in virtual cluster 220, determining the optimum job 150 that is compatible with the space, and executing the determined job 150 in the available space. The following description will focus on the operation of cluster management module 130 in performing this method. But, as with the previous flowchart, system 100 contemplates using any appropriate combination and arrangement of logical elements implementing some or all of the described functionality. Method 700 begins at step 705, where cluster management engine 130 sorts job queue 525. In the illustrated embodiment, cluster management engine 130 sorts the queue 525 based on the priority of jobs 150 stored in the queue 525. But it will be understood that cluster management engine 130 may sort queue 525 using any suitable characteristic such that the appropriate or optimal job 150 will be executed. Next, at step 710, cluster management engine 130 determines the number of available nodes 115 in one of the virtual clusters 220. Of course, cluster management engine 130 may also determine the number of available nodes 115 in grid 110 or in any one or more of virtual clusters 220. At step 715, cluster management engine 130 selects first job 150 from sorted job queue 525. Next, cluster management engine 130 dynamically determines the optimum shape (or other dimensions) of selected job 150 at 720. Once the optimum shape or dimension of selected job 150 is determined, then cluster management engine 130 determines if it can backfill job 150 in the appropriate virtual cluster 220 in steps 725 through 745. At decisional step 725, cluster management engine 130 determines if there are enough nodes 115 available for the selected job 150. If there are enough available nodes 115, then at step 730 cluster management engine 130 dynamically allocates nodes 115 for the selected job 150 using any appropriate technique. For example, cluster management engine 130 may use the techniques describes in FIG. 6. Next, at step 735, cluster management engine 130 recalculates the number of available nodes in virtual cluster 220. At step 740, cluster management engine 130 executes job 150 on allocated nodes 115. Once job 150 has been executed (or if there were not enough nodes 115 for selected job 150), then cluster management engine 130 selects the next job 150 in the sorted job queue 525 at step 745 and processing returns to step 720. It will be understood that while illustrated as a loop, cluster management engine 130 may initiate, execute, and terminate the techniques illustrated in method 700 at any appropriate time. FIG. 8 is a flowchart illustrating an example method 800 for dynamically managing failure of a node 115 in grid 110 in accordance with one embodiment of the present disclosure. At a high level, method 800 describes determining that node 115 failed, automatically performing job recovery and management, and replacing the failed node 115 with a secondary node 115. The following description will focus on the operation of cluster management module 130 in performing this method. But, as with the previous flowcharts, system 100 contemplates using any appropriate combination and arrangement of logical elements implementing some or all of the described functionality. Method 800 begins at step 805, where cluster management engine 130 determines that node 115 has failed. As described above, cluster management engine 130 may determine that node 115 has failed using any suitable technique. For example, cluster management engine 130 may pull nodes 115 (or agents 132) at various times and may determine that node 115 has failed based upon the lack of a response from node 115. In another example, agent 132 existing on node 115 may communicate a “heartbeat” and the lack of this “heartbeat” may indicate node 115 failure. Next, at step 810, cluster management engine 130 removes the failed node 115 from virtual cluster 220. In one embodiment, cluster management engine 130 may change the status of node 115 in virtual list 522 from “allocated” to “failed”. Cluster management engine 130 then determines if a job 150 is associated with failed node 115 at decisional step 815. If there is no job 150 associated with node 115, then processing ends. As described above, before processing ends, cluster management engine 130 may communicate an error message to an administrator, automatically determine a replacement node 115, or any other suitable processing. If there is a job 150 associated with the failed node 115, then the cluster management engine 130 determines other nodes 115 associated with the job 150 at step 820. Next, at step 825, cluster management engine 130 kills job 150 on all appropriate nodes 115. For example, cluster management engine 130 may execute a kill job command or use any other appropriate technique to end job 150. Next, at step 830, cluster management engine 130 de-allocates nodes 115 using virtual list 522. For example, cluster management engine 130 may change the status of nodes 115 in virtual list 522 from “allocated” to “available”. Once the job has been terminated and all appropriate nodes 115 de-allocated, then cluster management engine 130 attempts to re-execute the job 150 using available nodes 115 in steps 835 through 850. At step 835, cluster management engine 130 retrieves policy 524 and parameters for the killed job 150 at step 835. Cluster management engine 130 then determines the optimum subset 230 of nodes 115 in virtual cluster 220, at step 840, based on the retrieved policy 524 and the job parameters. Once the subset 230 of nodes 115 has been determined, then cluster management engine 130 dynamically allocates the subset 230 of nodes 115 at step 845. For example, cluster management engine 130 may change the status of nodes 115 in virtual list 522 from “unallocated” to “allocated”. It will be understood that this subset of nodes 115 may be different from the original subset of nodes that job 150 was executing on. For example, cluster management engine 130 may determine that a different subset of nodes is optimal because of the node failure that prompted this execution. In another example, cluster management engine 130 may have determined that a secondary node 115 was operable to replace the failed node 115 and the new subset 230 is substantially similar to the old job space 230. Once the allocated subset 230 has been determined and allocated, then cluster management engine 130 executes job 150 at step 850. The preceding flowcharts and accompanying description illustrate exemplary methods 600, 700, and 800. In short, system 100 contemplates using any suitable technique for performing these and other tasks. Accordingly, many of the steps in this flowchart may take place simultaneously and/or in different orders than as shown. Moreover, system 100 may use methods with additional steps, fewer steps, and/or different steps, so long as the methods remain appropriate. Although this disclosure has been described in terms of certain embodiments and generally associated methods, alterations and permutations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of example embodiments does not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of this disclosure. | <SOH> BACKGROUND OF THE INVENTION <EOH>High Performance Computing (HPC) is often characterized by the computing systems used by scientists and engineers for modeling, simulating, and analyzing complex physical or algorithmic phenomena. Currently, HPC machines are typically designed using numerous HPC clusters of one or more processors referred to as nodes. For most large scientific and engineering applications, performance is chiefly determined by parallel scalability and not the speed of individual nodes; therefore, scalability is often a limiting factor in building or purchasing such high performance clusters. Scalability is generally considered to be based on i) hardware, ii) memory, I/O, and communication bandwidth; iii) software; iv) architecture; and v) applications. The processing, memory, and I/O bandwidth in most conventional HPC environments are normally not well balanced and, therefore, do not scale well. Many HPC environments do not have the I/O bandwidth to satisfy high-end data processing requirements or are built with blades that have too many unneeded components installed, which tend to dramatically reduce the system's reliability. Accordingly, many HPC environments may not provide robust cluster management software for efficient operation in production-oriented environments. | <SOH> SUMMARY OF THE INVENTION <EOH>This disclosure provides a High Performance Computing (HPC) node comprises a motherboard, a switch comprising eight or more ports integrated on the motherboard, and at least two processors operable to execute an HPC job, with each processor communicably coupled to the integrated switch and integrated on the motherboard. The invention has several important technical advantages. For example, one possible advantage of the present invention is that by at least partially reducing, distributing, or eliminating centralized switching functionality, it may provide greater input/output (I/O) performance, perhaps four to eight times the conventional HPC bandwidth. Indeed, in certain embodiments, the I/O performance may nearly equal processor performance. This well-balanced approach may be less sensitive to communications overhead. Accordingly, the present invention may increase blade and overall system performance. A further possible advantage is reduced interconnect latency. Further, the present invention may be more easily scaleable, reliable, and fault tolerant than conventional blades. Yet another advantage may be a reduction of the costs involved in manufacturing an HPC server, which may be passed on to universities and engineering labs, and/or the costs involved in performing HPC processing. The invention may further allow for management software that is more robust and efficient based, at least in part, on the balanced architecture. Various embodiments of the invention may have none, some, or all of these advantages. Other technical advantages of the present invention will be readily apparent to one skilled in the art. | 20040415 | 20121218 | 20051020 | 96346.0 | 3 | GEIB, BENJAMIN P | COUPLING PROCESSORS TO EACH OTHER FOR HIGH PERFORMANCE COMPUTING (HPC) | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,825,021 | ACCEPTED | System and method for topology-aware job scheduling and backfilling in an HPC environment | A method for job management in an HPC environment includes determining an unallocated subset from a plurality of HPC nodes, with each of the unallocated HPC nodes comprising an integrated fabric. An HPC job is selected from a job queue and executed using at least a portion of the unallocated subset of nodes. | 1. A method for job management in an HPC environment comprising: determining an unallocated subset from a plurality of HPC nodes, each of the unallocated HPC nodes comprising an integrated fabric; selecting an HPC job from a job queue; and executing the selected job using at least a portion of the unallocated subset of nodes. 2. The method of claim 1, wherein selecting the HPC job comprises selecting the HPC job from the job queue based on priority, the selected job comprising dimensions not greater than a topology of the unallocated subset. 3. The method of claim 2, wherein selecting the HPC job from the job queue based on priority comprises: sorting the job queue based on job priority; selecting a first HPC job from the sorted job queue; determining dimensions of the first HPC job with the topology of the unallocated subset; and in response to the dimensions of the first HPC job being greater than the topology of the unallocated subset, selecting a second HPC job from the sorted job queue. 4. The method of claim 2, wherein the dimensions of the first HPC job are based, at least in part, on one or more job parameters and an associated policy. 5. The method of claim 2, further comprising: dynamically allocating a job spare from the unallocated subset based, at least in part, on the dimensions of the HPC job; and wherein executing the selected job comprises executing the selected job using the dynamically allocated job spare. 6. The method of claim 1, the plurality of HPC nodes comprising a first plurality and the method further comprising: determining that dimensions of the selected job are greater than a topology of the first plurality; selecting one or more HPC nodes from a second plurality, each of the second HPC nodes comprising an integrated fabric; and adding the selected second HPC nodes to the unallocated subset to satisfy the dimensions of the selected job. 7. The method of claim 6, further comprising returning the second HPC nodes to the second plurality. 8. The method of claim 1, further comprising; determining that a second HPC job that was executing on a second subset in the plurality of HPC nodes has failed; adding the second subset to the unallocated subset; and adding the failed job to the job queue. 9. Software for job management in an HPC environment operable to: determine an unallocated subset from a plurality of HPC nodes, each of the unallocated HPC nodes comprising an integrated fabric; select an HPC job from a job queue; and execute the selected job using at least a portion of the unallocated subset of nodes. 10. The software of claim 9, wherein the software operable to select the HPC job comprises software operable to select the HPC job from the job queue based on priority, the selected job comprising dimensions not greater than a topology of the unallocated subset. 11. The software of claim 10, wherein the software operable to select the HPC job from the job queue based on priority comprises software operable to: sort the job queue based on job priority; select a first HPC job from the sorted job queue; determine dimensions of the first HPC job with the topology of the unallocated subset; and in response to the dimensions of the first HPC job being greater than the topology of the unallocated subset, select a second HPC job from the sorted job queue. 12. The software of claim 10, wherein the dimensions of the first HPC job are based, at least in part, on one or more job parameters and an associated policy. 13. The software of claim 10, further operable to: dynamically allocate a job spare from the unallocated subset based, at least in part, on the dimensions of the HPC job; and wherein the software operable to execute the selected job comprises software operable to execute the selected job using the dynamically allocated job spare. 14. The software of claim 9, the plurality of HPC nodes comprising a first plurality and the software further operable to: determine that dimensions of the selected job are greater than a topology of the first plurality; select one or more HPC nodes from a second plurality, each of the second HPC nodes comprising an integrated fabric; and add the selected second HPC nodes to the unallocated subset to satisfy the dimensions of the selected job. 15. The software of claim 14, further comprising returning the second HPC nodes to the second plurality. 16. The software of claim 9, further operable to: determine that a second HPC job that was executing on a second subset in the plurality of HPC nodes has failed; add the second subset to the unallocated subset; and add the failed job to the job queue. 17. A system for job management in an HPC environment comprising: a plurality of HPC nodes, each node including an integrated fabric; and a management node operable to: determine an unallocated subset from the plurality of HPC nodes; select an HPC job from a job queue; and execute the selected job using at least a portion of the unallocated subset of nodes. 18. The system of claim 17, wherein the management node operable to select the HPC job comprises the management node operable to select the HPC job from the job queue based on priority, the selected job comprising dimensions not greater than a topology of the unallocated subset. 19. The system of claim 18, wherein the management node operable to select the HPC job from the job queue based on priority comprises the management node operable to: sort the job queue based on job priority; select a first HPC job from the sorted job queue; determine dimensions of the first HPC job with the topology of the unallocated subset; and in response to the dimensions of the first HPC job being greater than the topology of the unallocated subset, select a second HPC job from the sorted job queue. 20. The system of claim 18, wherein the dimensions of the first HPC job are based, at least in part, on one or more job parameters and an associated policy. 21. The system of claim 18, further operable to: dynamically allocate a job spare from the unallocated subset based, at least in part, on the dimensions of the HPC job; and wherein the management node operable to execute the selected job comprises the management node operable to execute the selected job using the dynamically allocated job spare. 22. The system of claim 17, the plurality of HPC nodes comprising a first plurality and the management node further operable to: determine that dimensions of the selected job are greater than a topology of the first plurality; select one or more HPC nodes from a second plurality, each of the second HPC nodes comprising an integrated fabric; and add the selected second HPC nodes to the unallocated subset to satisfy the dimensions of the selected job. 23. The system of claim 22, the management node further operable to return the second HPC nodes to the second plurality. 24. The system of claim 17, the management node further operable to: determine that a second HPC job that was executing on a second subset in the plurality of HPC nodes has failed; add the second subset to the unallocated subset; and add the failed job to the job queue. | TECHNICAL FIELD This disclosure relates generally to the field of data processing and, more specifically, to a system and method for topology-aware job scheduling and backfilling BACKGROUND OF THE INVENTION High Performance Computing (HPC) is often characterized by the computing systems used by scientists and engineers for modeling, simulating, and analyzing complex physical or algorithmic phenomena. Currently, HPC machines are typically designed using numerous HPC clusters of one or more processors referred to as nodes. For most large scientific and engineering applications, performance is chiefly determined by parallel scalability and not the speed of individual nodes; therefore, scalability is often a limiting factor in building or purchasing such high performance clusters. Scalability is generally considered to be based on i) hardware, ii) memory, I/O, and communication bandwidth; iii) software; iv) architecture; and v) applications. The processing, memory, and I/O bandwidth in most conventional HPC environments are normally not well balanced and, therefore, do not scale well. Many HPC environments do not have the I/O bandwidth to satisfy high-end data processing requirements or are built with blades that have too many unneeded components installed, which tend to dramatically reduce the system's reliability. Accordingly, many HPC environments may not provide robust cluster management software for efficient operation in production-oriented environments. SUMMARY OF THE INVENTION This disclosure provides a system and method for job management in an HPC environment that includes determining an unallocated subset from a plurality of HPC nodes, with each of the unallocated HPC nodes comprising an integrated fabric. An HPC job is selected from a job queue and executed using at least a portion of the unallocated subset of nodes. The invention has several important technical advantages. For example, one possible advantage of the present invention is that by at least partially reducing, distributing, or eliminating centralized switching functionality, it may provide greater input/output (I/O) performance, perhaps four to eight times the conventional HPC bandwidth. Indeed, in certain embodiments, the I/O performance may nearly equal processor performance. This well-balanced approach may be less sensitive to communications overhead. Accordingly, the present invention may increase blade and overall system performance. A further possible advantage is reduced interconnect latency. Further, the present invention may be more easily scaleable, reliable, and fault tolerant than conventional blades. Yet another advantage may be a reduction of the costs involved in manufacturing an HPC server, which may be passed on to universities and engineering labs, and/or the costs involved in performing HPC processing. The invention may further allow for management software that is more robust and efficient based, at least in part, on the balanced architecture. Various embodiments of the invention may have none, some, or all of these advantages. Other technical advantages of the present invention will be readily apparent to one skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present disclosure and its advantages, reference is now made to the following descriptions, taken in conjunction with the accompanying drawings, in which: FIG. 1 illustrates an example high-performance computing system in accordance with one embodiment of the present disclosure; FIGS. 2A-D illustrate various embodiments of the grid in the system of FIG. 1 and the usage thereof; FIGS. 3A-C illustrate various embodiments of individual nodes in the system of FIGS. 1; FIGS. 4A-B illustrate various embodiments of a graphical user interface in accordance with the system of FIG. 1; FIG. 5 illustrates one embodiment of the cluster management software in accordance with the system in FIG. 1; FIG. 6 is a flowchart illustrating a method for submitting a batch job in accordance with the high-performance computing system of FIG. 1; FIG. 7 is a flowchart illustrating a method for dynamic backfilling of the grid in accordance with the high-performance computing system of FIG. 1; and FIG. 8 is a flow chart illustrating a method for dynamically managing a node failure in accordance with the high-performance computing system of FIG. 1. DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating a high Performance Computing (HPC) system 100 for executing software applications and processes, for example an atmospheric, weather, or crash simulation, using HPC techniques. System 100 provides users with HPC functionality dynamically allocated among various computing nodes 115 with I/O performance substantially similar to the processing performance. Generally, these nodes 115 are easily scaleable because of, among other things, this increased input/output (I/O) performance and reduced fabric latency. For example, the scalability of nodes 115 in a distributed architecture may be represented by a derivative of Amdahl's law: S(N)=1/((FP/N)+FS)*(1−Fc*(1−RR/L)) where S(N)=Speedup on N processors, Fp=Fraction of Parallel Code, Fs=Fraction of Non-Parallel Code, Fc=Fraction of processing devoted to communications, and RR/L=Ratio of Remote/Local Memory Bandwidth. Therefore, by HPC system 100 providing I/O performance substantially equal to or nearing processing performance, HPC system 100 increases overall efficiency of HPC applications and allows for easier system administration. HPC system 100 is a distributed client/server system that allows users (such as scientists and engineers) to submit jobs 150 for processing on an HPC server 102. For example, system 100 may include HPC server 102 that is connected, through network 106, to one or more administration workstations or local clients 120. But system 100 may be a standalone computing environment or any other suitable environment. In short, system 100 is any HPC computing environment that includes highly scaleable nodes 115 and allows the user to submit jobs 150, dynamically allocates scaleable nodes 115 for job 150, and automatically executes job 150 using the allocated nodes 115. Job 150 may be any batch or online job operable to be processed using HPC techniques and submitted by any apt user. For example, job 150 may be a request for a simulation, a model, or for any other high-performance requirement. Job 150 may also be a request to run a data center application, such as a clustered database, an online transaction processing system, or a clustered application server. The term “dynamically,” as used herein, generally means that certain processing is determined, at least in part, at run-time based on one or more variables. The term “automatically,” as used herein, generally means that the appropriate processing is substantially performed by at least part of HPC system 100. It should be understood that “automatically” further contemplates any suitable user or administrator interaction with system 100 without departing from the scope of this disclosure. HPC server 102 comprises any local or remote computer operable to process job 150 using a plurality of balanced nodes 115 and cluster management engine 130. Generally, HPC server 102 comprises a distributed computer such as a blade server or other distributed server. However the configuration, server 102 includes a plurality of nodes 115. Nodes 115 comprise any computer or processing device such as, for example, blades, general-purpose personal computers (PC), Macintoshes, workstations, Unix-based computers, or any other suitable devices. Generally, FIG. 1 provides merely one example of computers that may be used with the disclosure. For example, although FIG. 1 illustrates one server 102 that may be used with the disclosure, system 100 can be implemented using computers other than servers, as well as a server pool. In other words, the present disclosure contemplates computers other than general purpose computers as well as computers without conventional operating systems. As used in this document, the term “computer” is intended to encompass a personal computer, workstation, network computer, or any other suitable processing device. HPC server 102, or the component nodes 115, may be adapted to execute any operating system including Linux, UNIX, Windows Server, or any other suitable operating system. According to one embodiment, HPC server 102 may also include or be communicably coupled with a remote web server. Therefore, server 102 may comprise any computer with software and/or hardware in any combination suitable to dynamically allocate nodes 115 to process HPC job 150. At a high level, HPC server 102 includes a management node 105, a grid 110 comprising a plurality of nodes 115, and cluster management engine 130. More specifically, server 102 may be a standard 19″ rack including a plurality of blades (nodes 115) with some or all of the following components: i) dual-processors; ii) large, high bandwidth memory; iii) dual host channel adapters (HCAs); iv) integrated fabric switching; v) FPGA support; and vi) redundant power inputs or N+1 power supplies. These various components allow for failures to be confined to the node level. But it will be understood that HPC server 102 and nodes 115 may not include all of these components. Management node 105 comprises at least one blade substantially dedicated to managing or assisting an administrator. For example, management node 105 may comprise two blades, with one of the two blades being redundant (such as an active/passive configuration). In one embodiment, management node 105 may be the same type of blade or computing device as HPC nodes 115. But, management node 105 may be any node, including any number of circuits and configured in any suitable fashion, so long as it remains operable to at least partially manage grid 110. Often, management node 105 is physically or logically separated from the plurality of HPC nodes 115, jointly represented in grid 110. In the illustrated embodiment, management node 105 may be communicably coupled to grid 110 via link 108. Link 108 may comprise any communication conduit implementing any appropriate communications protocol. In one embodiment, link 108 provides Gigabit or 10 Gigabit Ethernet communications between management node 105 and grid 110. Grid 110 is a group of nodes 115 interconnected for increased processing power. Typically, grid 110 is a 3D Torus, but it may be a mesh, a hypercube, or any other shape or configuration without departing from the scope of this disclosure. The links between nodes 115 in grid 110 may be serial or parallel analog links, digital links, or any other type of link that can convey electrical or electromagnetic signals such as, for example, fiber or copper. Each node 115 is configured with an integrated switch. This allows node 115 to more easily be the basic construct for the 3D Torus and helps minimize XYZ distances between other nodes 115. Further, this may make copper wiring work in larger systems at up to Gigabit rates with, in some embodiments, the longest cable being less than 5 meters. In short, node 115 is generally optimized for nearest-neighbor communications and increased I/O bandwidth. Each node 115 may include a cluster agent 132 communicably coupled with cluster management engine 130. Generally, agent 132 receives requests or commands from management node 105 and/or cluster management engine 130. Agent 132 could include any hardware, software, firmware, or combination thereof operable to determine the physical status of node 115 and communicate the processed data, such as through a “heartbeat,” to management node 105. In another embodiment, management node 105 may periodically poll agent 132 to determine the status of the associated node 115. Agent 132 may be written in any appropriate computer language such as, for example, C, C++, Assembler, Java, Visual Basic, and others or any combination thereof so long as it remains compatible with at least a portion of cluster management engine 130. Cluster management engine 130 could include any hardware, software, firmware, or combination thereof operable to dynamically allocate and manage nodes 115 and execute job 150 using nodes 115. For example, cluster management engine 130 may be written or described in any appropriate computer language including C, C++, Java, Visual Basic, assembler, any suitable version of 4GL, and others or any combination thereof. It will be understood that while cluster management engine 130 is illustrated in FIG. 1 as a single multi-tasked module, the features and functionality performed by this engine may be performed by multiple modules such as, for example, a physical layer module, a virtual layer module, a job scheduler, and a presentation engine (as shown in more detail in FIG. 5). Further, while illustrated as external to management node 105, management node 105 typically executes one or more processes associated with cluster management engine 130 and may store cluster management engine 130. Moreover, cluster management engine 130 may be a child or sub-module of another software module without departing from the scope of this disclosure. Therefore, cluster management engine 130 comprises one or more software modules operable to intelligently manage nodes 115 and jobs 150. Server 102 may include interface 104 for communicating with other computer systems, such as client 120, over network 106 in a client-server or other distributed environment. In certain embodiments, server 102 receives jobs 150 or job policies from network 106 for storage in disk farm 140. Disk farm 140 may also be attached directly to the computational array using the same wideband interfaces that interconnects the nodes. Generally, interface 104 comprises logic encoded in software and/or hardware in a suitable combination and operable to communicate with network 106. More specifically, interface 104 may comprise software supporting one or more communications protocols associated with communications network 106 or hardware operable to communicate physical signals. Network 106 facilitates wireless or wireline communication between computer server 102 and any other computer, such as clients 120. Indeed, while illustrated as residing between server 102 and client 120, network 106 may also reside between various nodes 115 without departing from the scope of the disclosure. In other words, network 106 encompasses any network, networks, or sub-network operable to facilitate communications between various computing components. Network 106 may communicate, for example, Internet Protocol (IP) packets, Frame Relay frames, Asynchronous Transfer Mode (ATM) cells, voice, video, data, and other suitable information between network addresses. Network 106 may include one or more local area networks (LANs), radio access networks (RANs), metropolitan area networks (MANs), wide area networks (WANs), all or a portion of the global computer network known as the Internet, and/or any other communication system or systems at one or more locations. In general, disk farm 140 is any memory, database or storage area network (SAN) for storing jobs 150, profiles, boot images, or other HPC information. According to the illustrated embodiment, disk farm 140 includes one or more storage clients 142. Disk farm 140 may process and route data packets according to any of a number of communication protocols, for example, InfiniBand (IB), Gigabit Ethernet (GE), or FibreChannel (FC). Data packets are typically used to transport data within disk farm 140. A data packet may include a header that has a source identifier and a destination identifier. The source identifier, for example, a source address, identifies the transmitter of information, and the destination identifier, for example, a destination address, identifies the recipient of the information. Client 120 is any device operable to present the user with a job submission screen or administration via a graphical user interface (GUI) 126. At a high level, illustrated client 120 includes at least GUI 126 and comprises an electronic computing device operable to receive, transmit, process and store any appropriate data associated with system 100. It will be understood that there may be any number of clients 120 communicably coupled to server 102. Further, “client 120” and “user of client 120” may be used interchangeably as appropriate without departing from the scope of this disclosure. Moreover, for ease of illustration, each client is described in terms of being used by one user. But this disclosure contemplates that many users may use one computer to communicate jobs 150 using the same GUI 126. As used in this disclosure, client 120 is intended to encompass a personal computer, touch screen terminal, workstation, network computer, kiosk, wireless data port, cell phone, personal data assistant (PDA), one or more processors within these or other devices, or any other suitable processing device. For example, client 120 may comprise a computer that includes an input device, such as a keypad, touch screen, mouse, or other device that can accept information, and an output device that conveys information associated with the operation of server 102 or clients 120, including digital data, visual information, or GUI 126. Both the input device and output device may include fixed or removable storage media such as a magnetic computer disk, CD-ROM, or other suitable media to both receive input from and provide output to users of clients 120 through the administration and job submission display, namely GUI 126. GUI 126 comprises a graphical user interface operable to allow i) the user of client 120 to interface with system 100 to submit one or more jobs 150; and/or ii) the system (or network) administrator using client 120 to interface with system 100 for any suitable supervisory purpose. Generally, GUI 126 provides the user of client 120 with an efficient and user-friendly presentation of data provided by HPC system 100. GUI 126 may comprise a plurality of customizable frames or views having interactive fields, pull-down lists, and buttons operated by the user. In one embodiment, GUI 126 presents a job submission display that presents the various job parameter fields and receives commands from the user of client 120 via one of the input devices. GUI 126 may, alternatively or in combination, present the physical and logical status of nodes 115 to the system administrator, as illustrated in FIGS. 4A-B, and receive various commands from the administrator. Administrator commands may include marking nodes as (un)available, shutting down nodes for maintenance, rebooting nodes, or any other suitable command. Moreover, it should be understood that the term graphical user interface may be used in the singular or in the plural to describe one or more graphical user interfaces and each of the displays of a particular graphical user interface. Therefore, GUI 126 contemplates any graphical user interface, such as a generic web browser, that processes information in system 100 and efficiently presents the results to the user. Server 102 can accept data from client 120 via the web browser (e.g., Microsoft Internet Explorer or Netscape Navigator) and return the appropriate HTML or XML responses using network 106. In one aspect of operation, HPC server 102 is first initialized or booted. During this process, cluster management engine 130 determines the existence, state, location, and/or other characteristics of nodes 115 in grid 110. As described above, this may be based on a “heartbeat” communicated upon each node's initialization or upon near immediate polling by management node 105. Next, cluster management engine 130 may dynamically allocate various portions of grid 110 to one or more virtual clusters 220 based on, for example, predetermined policies. In one embodiment, cluster management engine 130 continuously monitors nodes 115 for possible failure and, upon determining that one of the nodes 115 failed, effectively managing the failure using any of a variety of recovery techniques. Cluster management engine 130 may also manage and provide a unique execution environment for each allocated node of virtual cluster 220. The execution environment may consist of the hostname, IP address, operating system, configured services, local and shared file systems, and a set of installed applications and data. The cluster management engine 130 may dynamically add or subtract nodes from virtual cluster 220 according to associated policies and according to inter-cluster policies, such as priority. When a user logs on to client 120, he may be presented with a job submission screen via GUI 126. Once the user has entered the job parameters and submitted job 150, cluster management engine 130 processes the job submission, the related parameters, and any predetermined policies associated with job 150, the user, or the user group. Cluster management engine 130 then determines the appropriate virtual cluster 220 based, at least in part, on this information. Engine 130 then dynamically allocates a job space 230 within virtual cluster 220 and executes job 150 across the allocated nodes 115 using HPC techniques. Based, at least in part, on the increased I/O performance, HPC server 102 may more quickly complete processing of job 150. Upon completion, cluster management engine communicates results 160 to the user. FIGS. 2A-D illustrate various embodiments of grid 210 in system 100 and the usage or topology thereof. FIG. 2A illustrates one configuration, namely a 3D Torus, of grid 210 using a plurality of node types. For example, the illustrated node types are external I/O node, FS server, FS metadata server, database server, and compute node. FIG. 2B illustrates an example of “folding” of grid 210. Folding generally allows for one physical edge of grid 215 to connect to a corresponding axial edge, thereby providing a more robust or edgeless topology. In this embodiment, nodes 215 are wrapped around to provide a near seamless topology connect by node link 216. Node line 216 may be any suitable hardware implementing any communications protocol for interconnecting two or more nodes 215. For example, node line 216 may be copper wire or fiber optic cable implementing Gigabit Ethernet. FIG. 2C illustrates grid 210 with one virtual cluster 220 allocated within it. While illustrated with only one virtual cluster 220, there may be any number (including zero) of virtual clusters 220 in grid 210 without departing from the scope of this disclosure. Virtual cluster 220 is a logical grouping of nodes 215 for processing related jobs 150. For example, virtual cluster 220 may be associated with one research group, a department, a lab, or any other group of users likely to submit similar jobs 150. Virtual cluster 220 may be any shape and include any number of nodes 215 within grid 210. Indeed, while illustrated virtual cluster 220 includes a plurality of physically neighboring nodes 215, cluster 220 may be a distributed cluster of logically related nodes 215 operable to process job 150. Virtual cluster 220 may be allocated at any appropriate time. For example, cluster 220 may be allocated upon initialization of system 100 based, for example, on startup parameters or may be dynamically allocated based, for example, on changed server 102 needs. Moreover, virtual cluster 220 may change its shape and size over time to quickly respond to changing requests, demands, and situations. For example; virtual cluster 220 may be dynamically changed to include an automatically allocated first node 215 in response to a failure of a second node 215, previously part of cluster 220. In certain embodiments, clusters 220 may share nodes 215 as processing requires. FIG. 2D illustrates various job spaces, 230a and 230b respectively, allocated within example virtual cluster 220. Generally, job space 230 is a set of nodes 215 within virtual cluster 220 dynamically allocated to complete received job 150. Typically, there is one job space 230 per executing job 150 and vice versa, but job spaces 230 may share nodes 215 without departing from the scope of the disclosure. The dimensions of job space 230 may be manually input by the user or administrator or dynamically determined based on job parameters, policies, and/or any other suitable characteristic. FIGS. 3A-C illustrate various embodiments of individual nodes 115 in grid 110. In the illustrated, but example, embodiments, nodes 115 are represented by blades 315. Blade 315 comprises any computing device in any orientation operable to process all or a portion, such as a thread or process, of job 150. For example, blade 315 may be a standard Xeon64™ motherboard, a standard PCI-Express Opteron™ motherboard, or any other suitable computing card. Blade 315 is an integrated fabric architecture that distributes the fabric switching components uniformly across nodes 115 in grid 110, thereby possibly reducing or eliminating any centralized switching function, increasing the fault tolerance, and allowing message passing in parallel. More specifically, blade 315 includes an integrated switch 345. Switch 345 includes any number of ports that may allow for different topologies. For example, switch 345 may be an eight-port switch that enables a tighter three-dimensional mesh or 3D Torus topology. These eight ports include two “X” connections for linking to neighbor nodes 115 along an X-axis, two “Y” connections for linking to neighbor nodes 115 along a Y-axis, two “Z” connections for linking to neighbor nodes 115 along a Z-axis, and two connections for linking to management node 105. In one embodiment, switch 345 may be a standard eight port Infiniband-4x switch IC, thereby easily providing built-in fabric switching. Switch 345 may also comprise a twenty-four port switch that allows for multidimensional topologies, such a 4-D Torus, or other non-traditional topologies of greater than three dimensions. Moreover, nodes 115 may further interconnected along a diagonal axis, thereby reducing jumps or hops of communications between relatively distant nodes 115. For example, a first node 115 may be connected with a second node 115 that physically resides along a northeasterly axis several three dimensional “jumps” away. FIG. 3A illustrates a blade 315 that, at a high level, includes at least two processors 320a and 320b, local or remote memory 340, and integrated switch (or fabric) 345. Processor 320 executes instructions and manipulates data to perform the operations of blade 315 such as, for example, a central processing unit (CPU). Reference to processor 320 is meant to include multiple processors 320 where applicable. In one embodiment, processor 320 may comprise a Xeon64 or Itanium™ processor or other similar processor or derivative thereof. For example, the Xeon64 processor may be a 3.4 GHz chip with a 2 MB Cache and HyperTreading. In this embodiment, the dual processor module may include a native PCI/Express that improves efficiency. Accordingly, processor 320 has efficient memory bandwidth and, typically, has the memory controller built into the processor chip. Blade 315 may also include Northbridge 321, Southbridge 322, PCI channel 325, HCA 335, and memory 340. Northbridge 321 communicates with processor 320 and controls communications with memory 340, a PCI bus, Level 2 cache, and any other related components. In one embodiment, Northbridge 321 communicates with processor 320 using the frontside bus (FSB). Southbridge 322 manages many of the input/output (I/O) functions of blade 315. In another embodiment, blade 315 may implement the Intel Hub Architecture (IHA™), which includes a Graphics and AGP Memory Controller Hub (GMCH) and an I/O Controller Hub (ICH). PCI channel 325 comprises any high-speed, low latency link designed to increase the communication speed between integrated components. This helps reduce the number of buses in blade 315, which can reduce system bottlenecks. HCA 335 comprises any component providing channel-based I/O within server 102. Each HCA 335 may provide a total bandwidth of 2.65 GB/sec, thereby allowing 1.85 GB/sec per PE to switch 345 and 800 MB/sec per PE to I/O such as, for example, BIOS (Basic Input/Output System), an Ethernet management interface, and others. This further allows the total switch 345 bandwidth to be 3.7 GB/sec for 13.6 Gigaflops/sec peak or 0.27 Bytes/Flop I/O rate is 50 MB/sec per Gigaflop. Memory 340 includes any memory or database module and may take the form of volatile or non-volatile memory including, without limitation, magnetic media, optical media, flash memory, random access memory (RAM), read-only memory (ROM), removable media, or any other suitable local or remote memory component. In the illustrated embodiment, memory 340 is comprised of 8 GB of dual double data rate (DDR) memory components operating at least 6.4 GB/s. Memory 340 may include any appropriate data for managing or executing HPC jobs 150 without departing from this disclosure. FIG. 3B illustrates a blade 315 that includes two processors 320a and 320b, memory 340, HyperTransport/peripheral component interconnect (HT/PCI) bridges 330a and 330b, and two HCAs 335a and 335b. Example blade 315 includes at least two processors 320. Processor 320 executes instructions and manipulates data to perform the operations of blade 315 such as, for example, a central processing unit (CPU). In the illustrated embodiment, processor 320 may comprise an Opteron processor or other similar processor or derivative. In this embodiment, the Opteron processor design supports the development of a well balanced building block for grid 110. Regardless, the dual processor module may provide four to five Gigaflop usable performance and the next generation technology helps solve memory bandwidth limitation. But blade 315 may more than two processors 320 without departing from the scope of this disclosure. Accordingly, processor 320 has efficient memory bandwidth and, typically, has the memory controller built into the processor chip. In this embodiment, each processor 320 has one or more HyperTransport™ (or other similar conduit type) links 325. Generally, HT link 325 comprises any high-speed, low latency link designed to increase the communication speed between integrated components. This helps reduce the number of buses in blade 315, which can reduce system bottlenecks. HT link 325 supports processor to processor communications for cache coherent multiprocessor blades 315. Using HT links 325, up to eight processors 320 may be placed on blade 315. If utilized, HyperTransport may provide bandwidth of 6.4 GB/sec, 12.8, or more, thereby providing a better than forty-fold increase in data throughput over legacy PCI buses. Further HyperTransport technology may be compatible with legacy I/O standards, such as PCI, and other technologies, such as PCI-X. Blade 315 further includes HT/PCI bridge 330 and HCA 335. PCI bridge 330 may be designed in compliance with PCI Local Bus Specification Revision 2.2 or 3.0 or PCI Express Base Specification 1.0a or any derivatives thereof. HCA 335 comprises any component providing channel-based I/O within server 102. In one embodiment, HCA 335 comprises an Infiniband HCA. InfiniBand channels are typically created by attaching host channel adapters and target channel adapters, which enable remote storage and network connectivity into an InfiniBand fabric, illustrated in more detail in FIG. 3B. Hypertransport 325 to PCI-Express Bridge 330 and HCA 335 may create a full-duplex 2 GB/sec I/O channel for each processor 320. In certain embodiments, this provides sufficient bandwidth to support processor-processor communications in distributed HPC environment 100. Further, this provides blade 315 with I/O performance nearly or substantially balanced with the performance of processors 320. FIG. 3C illustrates another embodiment of blade 315 including a daughter board. In this embodiment, the daughter board may support 3.2 GB/sec or higher cache coherent interfaces. The daughter board is operable to include one or more Field Programmable Gate Arrays (FPGAs) 350. For example, the illustrated daughter board includes two FPGAs 350, represented by 350a and 350b, respectively. Generally, FPGA 350 provides blade 315 with non-standard interfaces, the ability to process custom algorithms, vector processors for signal, image, or encryption/decryption processing applications, and high bandwidth. For example, FPGA may supplement the ability of blade 315 by providing acceleration factors of ten to twenty times the performance of a general purpose processor for special functions such as, for example, low precision Fast Fourier Transform (FFT) and matrix arithmetic functions. The preceding illustrations and accompanying descriptions provide exemplary diagrams for implementing various scaleable nodes 115 (illustrated as example blades 315). However, these figures are merely illustrative and system 100 contemplates using any suitable combination and arrangement of elements for implementing various scalability schemes. Although the present invention has been illustrated and described, in part, in regard to blade server 102, those of ordinary skill in the art will recognize that the teachings of the present invention may be applied to any clustered HPC server environment. Accordingly, such clustered servers 102 that incorporate the techniques described herein may be local or a distributed without departing from the scope of this disclosure. Thus, these servers 102 may include HPC modules (or nodes 115) incorporating any suitable combination and arrangement of elements for providing high performance computing power, while reducing I/O latency. Moreover, the operations of the various illustrated HPC modules may be combined and/or separated as appropriate. For example, grid 110 may include a plurality of substantially similar nodes 115 or various nodes 115 implementing differing hardware or fabric architecture. FIGS. 4A-B illustrate various embodiments of a management graphical user interface 400 in accordance with the system 100. Often, management GUI 400 is presented to client 120 using GUI 126. In general, management GUI 400 presents a variety of management interactive screens or displays to a system administrator and/or a variety of job submission or profile screens to a user. These screens or displays are comprised of graphical elements assembled into various views of collected information. For example, GUI 400 may present a display of the physical health of grid 110 (illustrated in FIG. 4A) or the logical allocation or topology of nodes 115 in grid 110 (illustrated in FIG. 4B). FIG. 4A illustrates example display 400a. Display 400a may include information presented to the administrator for effectively managing nodes 115. The illustrated embodiment includes a standard web browser with a logical “picture” or screenshot of grid 110. For example, this picture may provide the physical status of grid 110 and the component nodes 115. Each node 115 may be one of any number of colors, with each color representing various states. For example, a failed node 115 may be red, a utilized or allocated node 115 may be black, and an unallocated node 115 may be shaded. Further, display 400a may allow the administrator to move the pointer over one of the nodes 115 and view the various physical attributes of it. For example, the administrator may be presented with information including “node,” “availability,” “processor utilization,” “memory utilization,” “temperature,” “physical location,” and “address.” Of course, these are merely example data fields and any appropriate physical or logical node information may be display for the administrator. Display 400a may also allow the administrator to rotate the view of grid 110 or perform any other suitable function. FIG. 4B illustrates example display 400b. Display 400b presents a view or picture of the logical state of grid 100. The illustrated embodiment presents the virtual cluster 220 allocated within grid 110. Display 400b further displays two example job spaces 230 allocate within cluster 220 for executing one or more jobs 150. Display 400b may allow the administrator to move the pointer over graphical virtual cluster 220 to view the number of nodes 115 grouped by various statuses (such as allocated or unallocated). Further, the administrator may move the pointer over one of the job spaces 230 such that suitable job information is presented. For example, the administrator may be able to view the job name, start time, number of nodes, estimated end time, processor usage, I/O usage, and others. It will be understood that management GUI 126 (represented above by example displays 400a and 400b, respectively) is for illustration purposes only and may include none, some, or all of the illustrated graphical elements as well as additional management elements not shown. FIG. 5 illustrates one embodiment of cluster management engine 130, shown here as engine 500, in accordance with system 100. In this embodiment, cluster management engine 500 includes a plurality of sub-modules or components: physical manager 505, virtual manager 510, job scheduler 515, and local memory or variables 520. Physical manager 505 is any software, logic, firmware, or other module operable to determine the physical health of various nodes 115 and effectively manage nodes 115 based on this determined health. Physical manager may use this data to efficiently determine and respond to node 115 failures. In one embodiment, physical manager 505 is communicably coupled to a plurality of agents 132, each residing on one node 115. As described above, agents 132 gather and communicate at least physical information to manager 505. Physical manager 505 may be further operable to communicate alerts to a system administrator at client 120 via network 106. Virtual manager 510 is any software, logic, firmware, or other module operable to manage virtual clusters 220 and the logical state of nodes 115. Generally, virtual manager 510 links a logical representation of node 115 with the physical status of node 115. Based on these links, virtual manager 510 may generate virtual clusters 220 and process various changes to these clusters 220, such as in response to node failure or a (system or user) request for increased HPC processing. Virtual manager 510 may also communicate the status of virtual cluster 220, such as unallocated nodes 115, to job scheduler 515 to enable dynamic backfilling of unexecuted, or queued, HPC processes and jobs 150. Virtual manager 510 may further determine the compatibility of job 150 with particular nodes 115 and communicate this information to job scheduler 515. In certain embodiments, virtual manager 510 may be an object representing an individual virtual cluster 220. Cluster management engine 500 may also include job scheduler 515. Job scheduler sub-module 515 is a topology-aware module that processes aspects of the system's resources, as well with the processors and the time allocations, to determine an optimum job space 230 and time. Factors that are often considered include processors, processes, memory, interconnects, disks, visualization engines, and others. In other words, job scheduler 515 typically interacts with GUI 126 to receive jobs 150, physical manager 505 to ensure the health of various nodes 115, and virtual manager 510 to dynamically allocate job space 230 within a certain virtual cluster 220. This dynamic allocation is accomplished through various algorithms that often incorporates knowledge of the current topology of grid 110 and, when appropriate, virtual cluster 220. Job scheduler 515 handles both batch and interactive execution of both serial and parallel programs. Scheduler 515 should also provide a way to implement policies 524 on selecting and executing various problems presented by job 150. Cluster management engine 500, such as through job scheduler 515, may be further operable to perform efficient check-pointing. Restart dumps typically comprise over seventy-five percent of data written to disk. This I/O is often done so that processing is not lost to a platform failure. Based on this, a file system's I/O can be segregated into two portions: productive I/O and defensive I/O. Productive I/O is the writing of data that the user calls for to do science such as, for example, visualization dumps, traces of key physics variables over time, and others. Defensive I/O is performed to manage a large simulation run over a substantial period of time. Accordingly, increased I/O bandwidth greatly reduces the time and risk involved in check-pointing. Returning to engine 500, local memory 520 comprises logical descriptions (or data structures) of a plurality of features of system 100. Local memory 520 may be stored in any physical or logical data storage operable to be defined, processed, or retrieved by compatible code. For example, local memory 520 may comprise one or more extensible Markup Language (XML) tables or documents. The various elements may be described in terms of SQL statements or scripts, Virtual Storage Access Method (VSAM) files, flat files, binary data files, Btrieve files, database files, or comma-separated-value (CSV) files. It will be understood that each element may comprise a variable, table, or any other suitable data structure. Local memory 520 may also comprise a plurality of tables or files stored on one server 102 or across a plurality of servers or nodes. Moreover, while illustrated as residing inside engine 500, some or all of local memory 520 may be internal or external without departing from the scope of this disclosure. Illustrated local memory 520 includes physical list 521, virtual list 522, group file 523, policy table 524, and job queue 525. But, while not illustrated, local memory 520 may include other data structures, including a job table and audit log, without departing from the scope of this disclosure. Returning to the illustrated structures, physical list 521 is operable to store identifying and physical management information about node 115. Physical list 521 may be a multi-dimensional data structure that includes at least one record per node 115. For example, the physical record may include fields such as “node,” “availability,” “processor utilization,” “memory utilization,” “temperature,” “physical location,” “address,” “boot images,” and others. It will be understood that each record may include none, some, or all of the example fields. In one embodiment, the physical record may provide a foreign key to another table, such as, for example, virtual list 522. Virtual list 522 is operable to store logical or virtual management information about node 115. Virtual list 522 may be a multi-dimensional data structure that includes at least one record per node 115. For example, the virtual record may include fields such as “node,” “availability,” “job,” “virtual cluster,” “secondary node,” “logical location,” “compatibility,” and others. It will be understood that each record may include none, some, or all of the example fields. In one embodiment, the virtual record may include a link to another table such as, for example, group file 523. Group file 523 comprises one or more tables or records operable to store user group and security information, such as access control lists (or ACLs). For example, each group record may include a list of available services, nodes 115, or jobs for a user. Each logical group may be associated with a business group or unit, a department, a project, a security group, or any other collection of one or more users that are able to submit jobs 150 or administer at least part of system 100. Based on this information, cluster management engine 500 may determine if the user submitting job 150 is a valid user and, if so, the optimum parameters for job execution. Further, group table 523 may associate each user group with a virtual cluster 220 or with one or more physical nodes 115, such as nodes residing within a particular group's domain. This allows each group to have an individual processing space without competing for resources. However, as described above, the shape and size of virtual cluster 220 may be dynamic and may change according to needs, time, or any other parameter. Policy table 524 includes one or more policies. It will be understood that policy table 524 and policy 524 may be used interchangeably as appropriate. Policy 524 generally stores processing and management information about jobs 150 and/or virtual clusters 220. For example, policies 524 may include any number of parameters or variables including problem size, problem run time, timeslots, preemption, users' allocated share of node 115 or virtual cluster 220, and such. Job queue 525 represents one or more streams of jobs 150 awaiting execution. Generally, queue 525 comprises any suitable data structure, such as a bubble array, database table, or pointer array, for storing any number (including zero) of jobs 150 or reference thereto. There may be one queue 525 associated with grid 110 or a plurality of queues 525, with each queue 525 associated with one of the unique virtual clusters 220 within grid 110. In one aspect of operation, cluster management engine 500 receives job 150, made up of N tasks which cooperatively solve a problem by performing calculations and exchanging information. Cluster management engine 500 allocates N nodes 115 and assigns each of the N tasks to one particular node 515 using any suitable technique, thereby allowing the problem to be solved efficiently. For example, cluster management engine 500 may utilize job parameters, such as job task placement strategy, supplied by the user. Regardless, cluster management engine 500 attempts to exploit the architecture of server 102, which in turn provides the quicker turnaround for the user and likely improves the overall throughput for system 100. In one embodiment, cluster management engine 500 then selects and allocates nodes 115 according to any of the following example topologies: Specified 2D (x,y) or 3D (x,y,z)—Nodes 115 are allocated and tasks may be ordered in the specified dimensions, thereby preserving efficient neighbor to neighbor communication. The specified topology manages a variety of jobs 150 where it is desirable that the physical communication topology match the problem topology allowing the cooperating tasks of job 150 to communicate frequently with neighbor tasks. For example, a request of 8 tasks in a 2×2×2 dimension (2, 2, 2) will be allocated in a cube. For best-fit purposes, 2D allocations can be “folded” into 3 dimensions (as discussed in FIG. 2D), while preserving efficient neighbor to neighbor communications. Cluster management engine 500 may be free to allocate the specified dimensional shape in any orientation. For example, a 2×2×8 box may be allocated within the available physical nodes vertically or horizontally Best Fit Cube—cluster management engine 500 allocates N nodes 115 in a cubic volume. This topology efficiently handles jobs 150 allowing cooperating tasks to exchange data with any other tasks by minimizing the distance between any two nodes 115. Best Fit Sphere—cluster management engine 500 allocates N nodes 115 in a spherical volume. For example, the first task may be placed in the center node 115 of the sphere with the rest of the tasks placed on nodes 115 surrounding the center node 115. It will be understood that the placement order of the remaining tasks is not typically critical. This topology may minimize the distance between the first task and all other tasks. This efficiently handles a large class of problems where tasks 2−N communicate with the first task, but not with each other. Random—cluster management engine 500 allocates N nodes 115 with reduced consideration for where nodes 115 are logically or physically located. In one embodiment, this topology encourages aggressive use of grid 110 for backfilling purposes, with little impact to other jobs 150. It will be understood that the prior topologies and accompanying description are for illustration purposes only and may not depict actual topologies used or techniques for allocating such topologies. Cluster management engine 500 may utilize a placement weight, stored as a job 150 parameter or policy 524 parameter. In one embodiment, the placement weight is a modifier value between 0 and 1, which represents how aggressively cluster management engine 500 should attempt to place nodes 115 according to the requested task (or process) placement strategy. In this example, a value of 0 represents placing nodes 115 only if the optimum strategy (or dimensions) is possible and a value of 1 represents placing nodes 115 immediately, as long as there are enough free or otherwise available nodes 115 to handle the request. Typically, the placement weight does not override administrative policies 524 such as resource reservation, in order to prevent starvation of large jobs 150 and preserve the job throughput of HPC system 100. The preceding illustration and accompanying description provide an exemplary modular diagram for engine 500 implementing logical schemes for managing nodes 115 and jobs 150. However, this figure is merely illustrative and system 100 contemplates using any suitable combination and arrangement of logical elements for implementing these and other algorithms. Thus, these software modules may include any suitable combination and arrangement of elements for effectively managing nodes 115 and jobs 150. Moreover, the operations of the various illustrated modules may be combined and/or separated as appropriate. FIG. 6 is a flowchart illustrating an example method 600 for dynamically processing a job submission in accordance with one embodiment of the present disclosure. Generally, FIG. 6 describes method 600, which receives a batch job submission, dynamically allocates nodes 115 into a job space 230 based on the job parameters and associated policies 524, and executes job 150 using the allocated space. The following description focuses on the operation of cluster management module 130 in performing method 600. But system 100 contemplates using any appropriate combination and arrangement of logical elements implementing some or all of the described functionality, so long as the functionality remains appropriate. Method 600 begins at step 605, where HPC server 102 receives job submission 150 from a user. As described above, in one embodiment the user may submit job 150 using client 120. In another embodiment, the user may submit job 150 directly using HPC server 102. Next, at step 610, cluster management engine 130 selects group 523 based upon the user. Once the user is verified, cluster management engine 130 compares the user to the group access control list (ACL) at step 615. But it will be understood that cluster management engine 130 may use any appropriate security technique to verify the user. Based upon determined group 523, cluster management engine 130 determines if the user has access to the requested service. Based on the requested service and hostname, cluster management engine 130 selects virtual cluster 220 at step 620. Typically, virtual cluster 220 may be identified and allocated prior to the submission of job 150. But, in the event virtual cluster 220 has not been established, cluster management engine 130 may automatically allocate virtual cluster 220 using any of the techniques described above. Next, at step 625, cluster management engine 130 retrieves policy 524 based on the submission of job 150. In one embodiment, cluster management engine 130 may determine the appropriate policy 524 associated with the user, job 150, or any other appropriate criteria. Cluster management engine 130 then determines or otherwise calculates the dimensions of job 150 at step 630. It will be understood that the appropriate dimensions may include length, width, height, or any other appropriate parameter or characteristic. As described above, these dimensions are used to determine the appropriate job space 230 (or subset of nodes 115) within virtual cluster 220. After the initial parameters have been established, cluster management 130 attempts to execute job 150 on HPC server 102 in steps 635 through 665. At decisional step 635, cluster management engine 130 determines if there are enough available nodes to allocate the desired job space 230, using the parameters already established. If there are not enough nodes 115, then cluster management engine 130 determines the earliest available subset 230 of nodes 115 in virtual cluster 220 at step 640. Then, cluster management engine 130 adds job 150 to job queue 125 until the subset 230 is available at step 645. Processing then returns to decisional step 635. Once there are enough nodes 115 available, then cluster management engine 130 dynamically determines the optimum subset 230 from available nodes 115 at step 650. It will be understood that the optimum subset 230 may be determined using any appropriate criteria, including fastest processing time, most reliable nodes 115, physical or virtual locations, or first available nodes 115. At step 655, cluster management engine 130 selects the determined subset 230 from the selected virtual cluster 220. Next, at step 660, cluster management engine 130 allocates the selected nodes 115 for job 150 using the selected subset 230. According to one embodiment, cluster management engine 130 may change the status of nodes 115 in virtual node list 522 from “unallocated” to “allocated”. Once subset 230 has been appropriately allocated, cluster management engine 130 executes job 150 at step 665 using the allocated space based on the job parameters, retrieved policy 524, and any other suitable parameters. At any appropriate time, cluster management engine 130 may communicate or otherwise present job results 160 to the user. For example, results 160 may be formatted and presented to the user via GUI 126. FIG. 7 is a flowchart illustrating an example method 700 for dynamically backfilling a virtual cluster 220 in grid 110 in accordance with one embodiment of the present disclosure. At a high level, method 700 describes determining available space in virtual cluster 220, determining the optimum job 150 that is compatible with the space, and executing the determined job 150 in the available space. The following description will focus on the operation of cluster management module 130 in performing this method. But, as with the previous flowchart, system 100 contemplates using any appropriate combination and arrangement of logical elements implementing some or all of the described functionality. Method 700 begins at step 705, where cluster management engine 130 sorts job queue 525. In the illustrated embodiment, cluster management engine 130 sorts the queue 525 based on the priority of jobs 150 stored in the queue 525. But it will be understood that cluster management engine 130 may sort queue 525 using any suitable characteristic such that the appropriate or optimal job 150 will be executed. Next, at step 710, cluster management engine 130 determines the number of available nodes 115 in one of the virtual clusters 220. Of course, cluster management engine 130 may also determine the number of available nodes 115 in grid 110 or in any one or more of virtual clusters 220. At step 715, cluster management engine 130 selects first job 150 from sorted job queue 525. Next, cluster management engine 130 dynamically determines the optimum shape (or other dimensions) of selected job 150 at 720. Once the optimum shape or dimension of selected job 150 is determined, then cluster management engine 130 determines if it can backfill job 150 in the appropriate virtual cluster 220 in steps 725 through 745. At decisional step 725, cluster management engine 130 determines if there are enough nodes 115 available for the selected job 150. If there are enough available nodes 115, then at step 730 cluster management engine 130 dynamically allocates nodes 115 for the selected job 150 using any appropriate technique. For example, cluster management engine 130 may use the techniques describes in FIG. 6. Next, at step 735, cluster management engine 130 recalculates the number of available nodes in virtual cluster 220. At step 740, cluster management engine 130 executes job 150 on allocated nodes 115. Once job 150 has been executed (or if there were not enough nodes 115 for selected job 150), then cluster management engine 130 selects the next job 150 in the sorted job queue 525 at step 745 and processing returns to step 720. It will be understood that while illustrated as a loop, cluster management engine 130 may initiate, execute, and terminate the techniques illustrated in method 700 at any appropriate time. FIG. 8 is a flowchart illustrating an example method 800 for dynamically managing failure of a node 115 in grid 110 in accordance with one embodiment of the present disclosure. At a high level, method 800 describes determining that node 115 failed, automatically performing job recovery and management, and replacing the failed node 115 with a secondary node 115. The following description will focus on the operation of cluster management module 130 in performing this method. But, as with the previous flowcharts, system 100 contemplates using any appropriate combination and arrangement of logical elements implementing some or all of the described functionality. Method 800 begins at step 805, where cluster management engine 130 determines that node 115 has failed. As described above, cluster management engine 130 may determine that node 115 has failed using any suitable technique. For example, cluster management engine 130 may pull nodes 115 (or agents 132) at various times and may determine that node 115 has failed based upon the lack of a response from node 115. In another example, agent 132 existing on node 115 may communicate a “heartbeat” and the lack of this “heartbeat” may indicate node 115 failure. Next, at step 810, cluster management engine 130 removes the failed node 115 from virtual cluster 220. In one embodiment, cluster management engine 130 may change the status of node 115 in virtual list 522 from “allocated” to “failed”. Cluster management engine 130 then determines if a job 150 is associated with failed node 115 at decisional step 815. If there is no job 150 associated with node 115, then processing ends. As described above, before processing ends, cluster management engine 130 may communicate an error message to an administrator, automatically determine a replacement node 115, or any other suitable processing. If there is a job 150 associated with the failed node 115, then the cluster management engine 130 determines other nodes 115 associated with the job 150 at step 820. Next, at step 825, cluster management engine 130 kills job 150 on all appropriate nodes 115. For example, cluster management engine 130 may execute a kill job command or use any other appropriate technique to end job 150. Next, at step 830, cluster management engine 130 de-allocates nodes 115 using virtual list 522. For example, cluster management engine 130 may change the status of nodes 115 in virtual list 522 from “allocated” to “available”. Once the job has been terminated and all appropriate nodes 115 de-allocated, then cluster management engine 130 attempts to re-execute the job 150 using available nodes 115 in steps 835 through 850. At step 835, cluster management engine 130 retrieves policy 524 and parameters for the killed job 150 at step 835. Cluster management engine 130 then determines the optimum subset 230 of nodes 115 in virtual cluster 220, at step 840, based on the retrieved policy 524 and the job parameters. Once the subset 230 of nodes 115 has been determined, then cluster management engine 130 dynamically allocates the subset 230 of nodes 115 at step 845. For example, cluster management engine 130 may change the status of nodes 115 in virtual list 522 from “unallocated” to “allocated”. It will be understood that this subset of nodes 115 may be different from the original subset of nodes that job 150 was executing on. For example, cluster management engine 130 may determine that a different subset of nodes is optimal because of the node failure that prompted this execution. In another example, cluster management engine 130 may have determined that a secondary node 115 was operable to replace the failed node 115 and the new subset 230 is substantially similar to the old job space 230. Once the allocated subset 230 has been determined and allocated, then cluster management engine 130 executes job 150 at step 850. The preceding flowcharts and accompanying description illustrate exemplary methods 600, 700, and 800. In short, system 100 contemplates using any suitable technique for performing these and other tasks. Accordingly, many of the steps in this flowchart may take place simultaneously and/or in different orders than as shown. Moreover, system 100 may use methods with additional steps, fewer steps, and/or different steps, so long as the methods remain appropriate. Although this disclosure has been described in terms of certain embodiments and generally associated methods, alterations and permutations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of example embodiments does not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of this disclosure. | <SOH> BACKGROUND OF THE INVENTION <EOH>High Performance Computing (HPC) is often characterized by the computing systems used by scientists and engineers for modeling, simulating, and analyzing complex physical or algorithmic phenomena. Currently, HPC machines are typically designed using numerous HPC clusters of one or more processors referred to as nodes. For most large scientific and engineering applications, performance is chiefly determined by parallel scalability and not the speed of individual nodes; therefore, scalability is often a limiting factor in building or purchasing such high performance clusters. Scalability is generally considered to be based on i) hardware, ii) memory, I/O, and communication bandwidth; iii) software; iv) architecture; and v) applications. The processing, memory, and I/O bandwidth in most conventional HPC environments are normally not well balanced and, therefore, do not scale well. Many HPC environments do not have the I/O bandwidth to satisfy high-end data processing requirements or are built with blades that have too many unneeded components installed, which tend to dramatically reduce the system's reliability. Accordingly, many HPC environments may not provide robust cluster management software for efficient operation in production-oriented environments. | <SOH> SUMMARY OF THE INVENTION <EOH>This disclosure provides a system and method for job management in an HPC environment that includes determining an unallocated subset from a plurality of HPC nodes, with each of the unallocated HPC nodes comprising an integrated fabric. An HPC job is selected from a job queue and executed using at least a portion of the unallocated subset of nodes. The invention has several important technical advantages. For example, one possible advantage of the present invention is that by at least partially reducing, distributing, or eliminating centralized switching functionality, it may provide greater input/output (I/O) performance, perhaps four to eight times the conventional HPC bandwidth. Indeed, in certain embodiments, the I/O performance may nearly equal processor performance. This well-balanced approach may be less sensitive to communications overhead. Accordingly, the present invention may increase blade and overall system performance. A further possible advantage is reduced interconnect latency. Further, the present invention may be more easily scaleable, reliable, and fault tolerant than conventional blades. Yet another advantage may be a reduction of the costs involved in manufacturing an HPC server, which may be passed on to universities and engineering labs, and/or the costs involved in performing HPC processing. The invention may further allow for management software that is more robust and efficient based, at least in part, on the balanced architecture. Various embodiments of the invention may have none, some, or all of these advantages. Other technical advantages of the present invention will be readily apparent to one skilled in the art. | 20040415 | 20121218 | 20051020 | 66125.0 | 2 | VO, TED T | SYSTEM AND METHOD FOR TOPOLOGY-AWARE JOB SCHEDULING AND BACKFILLING IN AN HPC ENVIRONMENT | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,825,070 | ACCEPTED | Clutch for transmission power and method of manufacturing friction substance for the clutch | The present invention relates to a clutch for transmission power. The clutch for transmission power according to the present invention includes flywheel, clutch cover and clutch disk assembly positioning between the flywheel and the clutch cover; moreover, the clutch disk assembly includes a clutch facing having main body portion formed with a center hole in the middle thereof, and a contacting portion wherein one side thereof faces the friction pad at said flywheel side and the other side thereof faces the press plate of said clutch cover, and the portion facing each other between the friction pad and the press plate is made of carbon-carbon composition; a spline hub being overlapped with one side of the clutch facing wherein a spline groove is formed in the inner diameter thereof; and a connecting means for connecting the clutch facing with the spline hub. Furthermore, the clutch disk assembly and the method of manufacturing the friction substance for clutch according to the invention can improve assemblability and reduce weight by simplifying it as a single part without using shock absorbing apparatus such as coil spring or the like on clutch disk assembly. In addition, the power transmission of an engine can be improved, and also it has an effect that an automobile can start softly and slippery does not occur even at abrupt acceleration by providing with carbon-carbon composition or carbon-silicon carbide composition having excellent shock absorption function. | 1. A clutch for transmission power formed with a flywheel, a clutch cover and a clutch disk assembly positioning between said flywheel and said clutch cover, wherein said clutch disk assembly comprises: a clutch facing having main body portion formed with a center hole in the middle thereof, and a contacting portion wherein one side thereof faces the friction pad at said flywheel side and the other side thereof faces the press plate of said clutch cover, and the portion facing each other between said friction pad and said press plate is made of carbon-carbon composition; a spline hub being overlapped with one side of said clutch facing wherein a spline groove is formed inside the inner diameter thereof; and a combining means for combining said clutch facing with said spline hub. 2. The clutch for transmission power of claim 1, wherein said spline hub is formed with a boss for inserting into said center hole of said clutch facing. 3. The clutch for transmission power of claim 1, wherein said combining means comprises: a retainer ring being overlapped with the other side of said clutch facing; and a fastening member for combining by passing through said clutch facing, said spline hub and said retainer ring together. 4. The clutch for transmission power of claim 3, wherein said fastening member includes either bolt or rivet. 5. The clutch for transmission power of claim 1, wherein said contacting portion is formed with carbon-carbon composition which is composed of 20˜75 weight % of carbon fiber and 25˜80 weight % of pitch. 6. The clutch for transmission power of claim 5, wherein said carbon fiber is a single fiber. 7. The clutch for transmission power of claim 5, wherein said carbon fiber is formed by stacking continuously woven carbon fabrics. 8. The clutch for transmission power of claim 1, wherein said contacting portion is formed with carbon-silicon carbide which is composed of 3˜20 weight % of silicon, 10˜60 weight % of silicon carbide, and 20˜87 weight % of pitch-containing carbon. 9. The clutch for transmission power of claim 8, wherein said carbon fiber is a single fiber. 10. The clutch for transmission power of claim 8, wherein said carbon fiber is formed by stacking continuously woven carbon fabrics. 11. The clutch for transmission power of claim 1, wherein said body portion is integrally formed with said contacting portion by using the same carbon-carbon composition material which is used for said contacting portion. 12. The clutch for transmission power of claim 1, wherein said press plate is provided with the press pad adjoining said clutch facing, and said press pad and said friction pad are formed with the same carbon-carbon composition which is used for said contacting portion. 13. A method of manufacturing the friction substance for a clutch comprising the steps of: performing a first thermal treatment wherein carbon fiber is thermally treated for graphitization at a first thermal processing temperature; producing a prepreg wherein resin is sprayed on carbon fiber fabrics for forming the prepreg; producing a preform wherein carbon fiber and resin are stacked on said prepreg for forming the preform; producing a mold wherein the mold is formed by using a press on said preform; and performing a second thermal treatment wherein said mold is thermally treated at a second thermal processing temperature. 14. The method of manufacturing the friction substance for the clutch of claim 13, further comprising the step of cutting said thermally treated carbon fiber at the length of 200˜2,000 μm by using fiber-cutting machine between the first thermal treatment process and the prepreg producing process. 15. The method of manufacturing the friction substance for the clutch of claim 14, further comprising a densification process for densifying said mold at a predetermined density using a carbonization/impregnation process for pressurizing at the carbonizing pressure of 50˜2,000 kg/cm2 within the range of 750˜1,400° C. for 3˜5 hours between said mold producing process and said second thermal treatment process. 16. The method of manufacturing the friction substance for the clutch of claim 15, wherein said predetermined density is 1.3˜1.6 g/cm3. 17. The method of manufacturing the friction substance for the clutch of claim 13, wherein said first thermal processing temperature is 2,000˜3,000° C. during the first thermal treatment process. 18. The method of manufacturing the friction substance for the clutch of claim 13, said mold is composed of 20˜75 weight % of carbon fiber and 25˜80 weight % of said resin, and molded through heating within the range of 200˜300° C. in a press. 19. The method of manufacturing the friction substance for the clutch of claim 13, wherein said second thermal treatment process is performed at the maximum temperature for 3˜5 hours under second thermal processing temperature of 1,700˜2,500° C., vacuum level of 3˜5 mmHg, and heat rising rate of 20˜100° C./hr. 20. The method of manufacturing the friction substance for the clutch of claim 13 further comprising the steps of: performing a silicon powder addition process for adding silicon powder to said mold after said second thermal treatment process; and performing a vacuum heating process for increasing the temperature within the range of 1,450° C.˜2,200° C. and maintaining it for 0.1˜5.0 hours under vacuum atmosphere. 21. The method of manufacturing the friction substance for the clutch of claim 20, wherein said silicon powder 0.2˜5.0 times heavier than said mold in weight ratio is added during said silicon powder addition process. 22. The method of manufacturing the friction substance for the clutch of claim 20, wherein said mold is composed of 3˜25 weight % of silicon, 10˜65 weight % of silicon carbide, and 10˜80 weight % of carbon after finishing the vacuum heating process. 23. The method of manufacturing the friction substance for the clutch of claim 13, wherein said mold is used for any one of clutch facing, friction pad, and press pad on which friction is made in the clutch. 24. The method of manufacturing the friction substance for the clutch comprising the steps of: heating for creating thermal gradient between the inside and outside of said preform by mounting a heating element on a three-dimensional preform; infiltrating reaction gas containing 1˜6 carbons per molecule inside said reactor; producing a mold by performing reaction under a predetermined condition; and performing a thermal treatment on said mold. 25. The method of manufacturing the friction substance for the clutch of claim 24, wherein said predetermined condition is heat rising rate of 10˜20° C./min, reaction temperature of 700˜1200° C., reaction gas concentration of 10˜100%, and reaction pressure of 250˜1,500 mbar. 26. The method of manufacturing the friction substance for the clutch of claim 24, wherein said thermal treatment process is performed at the maximum temperature for 3˜5 hours under second thermal processing temperature of 1,700˜2,500° C., vacuum level of 3˜5 mmHg, and heat rising rate of 20˜100° C./hr. 27. The method of manufacturing the friction substance for the clutch of claim 24, wherein said mold is used for any one of clutch facing, friction pad, and press pad on which friction is made in the clutch. | FIELD OF INVENTION The present invention relates to a clutch for transmission power and a method of manufacturing friction substance for the clutch, more particularly, to a clutch for transmission power and a method of manufacturing friction substance for the clutch wherein transmission power is excellent and soft start is attainable by simplifying the structure of spline hub as a single part, as well as by applying carbon-carbon composition having high performance in durability, shock absorption and friction. BACKGROUND OF THE INVENTION In general, a clutch characteristically requires response characteristics, such as soft gearshift and fast and high transmission power, as a mechanical element for transmitting power wherein a driving shaft and a driven shaft are connected to each other in mechanical devices. This clutch can be used for various industrial areas such as automobiles, motorcycles, industrial machines, presses, ships, etc. In particular, the clutch used for automobile is designed to allow slippery movement by half clutch operation to attain soft start for vehicles. Accordingly, high-temperature frictional heat can be created within the range of 200° C.˜600° C. with this half clutch operation. As a result, the clutch undergoes phenomena such as thermal load and fatigue, dynamic load by intermittent contact torque of the clutch caused by friction, and deterioration of clutch cover and disk at high temperature due to friction over the areas such as flywheel, clutch disk, press plate, etc. since high torque power is transmitted by friction. Caused by this phenomena, fatigue, crack or the like are created by thermal load and dynamic load, and also fading is created due to the reduced friction coefficient at high temperature as well as at high RPM (revolutions per minute). This is the main cause for reducing the life of a clutch. Various studies for solving the above-mentioned problem have been progressed until now. As for known solutions for these problems, there are a clutch cushion plate, a rubber damper, wave spring, etc. which are used for the shock absorption structure, and also a method of providing ventilation grooves at clutch disk or providing holes at flywheel or press plate was developed as cooling system. SUMMARY OF THE INVENTION It is an object of the invention to provide a clutch for transmission power for minimizing the damage on its life span which is induced by the friction at high temperature by providing the material of clutch facing with carbon-carbon composition having a simple structure without using a cushion plate, a rubber damper, wave spring or cooling system. It is another object of the invention to provide a method of manufacturing friction substance for the clutch wherein the friction substance that is used for the clutch such as clutch facing, press pad and friction pad can be produced with carbon-carbon composition. A clutch for transmission power to achieve the first object of the invention includes a flywheel, a clutch cover and a clutch disk assembly positioning between the flywheel and the clutch cover, wherein the clutch disk assembly includes a clutch facing having the body portion formed with a center hole in the middle thereof, and a contacting portion wherein one side thereof faces the friction pad at the flywheel side and the other side thereof faces the press plate of the clutch cover, and the portion facing each other between the friction pad and the press plate is made of carbon-carbon composition; a spline hub being overlapped with one side of the clutch facing wherein a spline groove is formed in the inner diameter thereof; and a combining means for combining the clutch facing with the spline hub. Moreover, the spline hub is formed with a boss for inserting into the center hole of the clutch facing, and the combining means includes a retainer ring being overlapped with the other side of the clutch facing; and a fastening member by passing through the clutch facing, the spline hub and the retainer ring. Here, the fastening member includes either bolt or rivet selectively. On the other hand, the contacting portion is formed with carbon-carbon composition which is composed of 20˜75 weight % of carbon fiber and 25˜80 weight % of pitch. Another aspect of the invention is that the contacting portion is made of carbon-silicon carbide which is composed of 3˜20 weight % of silicon, 10˜60 weight % of silicon carbide, and 20˜87 weight % of pitch-containing carbon. Furthermore, the carbon fiber is a single fiber, or it is formed by continuously woven carbon fabrics. In another aspect of the invention, moreover, the body portion is integrally formed with the contacting portion by using the same carbon-carbon composition material which is used for the contacting portion. Still another aspect of the invention is that the press plate is provided with the press pad adjoining the clutch facing, and the press pad and the friction pad are formed with the same carbon-carbon composition which is used for the contacting portion. The method of manufacturing the friction substance for the clutch to achieve the second object of the invention can be divided into two steps. The first step is to produce a two-dimensional preform, and the second step is to produce a three-dimensional preform. The method of producing a two-dimensional preform includes the steps of performing a first thermal treatment wherein carbon fiber is thermally treated for graphitization at a first thermal processing temperature, producing a prepreg wherein resin is sprayed on carbon fiber fabrics to form the prepreg, producing a preform wherein carbon fiber and resin are stacked on the prepreg to form the preform, producing a mold wherein the mold is formed by using a press on the preform, and performing a second thermal treatment wherein the mold is thermally treated at a second thermal processing temperature. Another aspect of the invention further includes the step of cutting the thermally treated carbon fiber at the length of 200˜2,000 μm by using fiber-cutting machine between the first thermal treatment process and the prepreg producing process. Still another aspect of the invention includes a densification process for densifying the mold at a predetermined density using a carbonization/impregnation process for pressurizing at the carbonizing pressure of 50˜2,000 kg/cm2 within the range of 750˜1,400° C. for 3˜5 hours between the mold producing process and the second thermal treatment process. Here, the predetermined density is 1.3˜1.6 g/cm3. In still further aspect of the invention, the first thermal processing temperature is 2,000˜3,000° C. during the first thermal treatment process. In the step of producing a mold, moreover, the mold is composed of 20˜75 weight % of carbon fiber and 25˜80 weight % of the resin, and molded by heating within the range of 200˜300° C. at the press. In another aspect of the invention, the second thermal treatment process is performed at the maximum temperature for 3˜5 hours under second thermal processing temperature of 1,700˜2,500° C., vacuum level of 3˜5 mmHg, and heat rising rate of 20˜100° C./hr. In still another aspect of the invention, it further includes the steps of performing a silicon powder addition process by adding silicon powder to the mold after the second thermal treatment process, and performing a vacuum heating process for increasing the temperature within the range of 1,450° C.˜2,200° C. and maintaining it for 0.1˜5.0 hours under the vacuum atmosphere, and silicon powder 0.2˜5.0 times heavier than the mold in weight ratio is added during the silicon powder addition process. After finishing the vacuum heating process, the mold is composed of 3˜25 weight % of silicon, 10˜65 weight % of silicon carbide, and 10˜80 weight % of carbon. The method of producing a three-dimensional preform includes the steps of heating for creating a thermal gradient between the inside and outside of the preform by mounting a heating element on the three-dimensional preform, infiltrating reaction gas containing 1˜6 carbons per molecule inside the reactor, producing a mold by performing reaction under a predetermined condition, and performing a thermal treatment on the mold. Furthermore, the predetermined condition is heat rising rate of 10˜20° C./min, reaction temperature of 700˜1200° C., reaction gas concentration of 10˜100%, and reaction pressure of 250˜1,500 mbar, and the thermal treatment process is performed at the maximum temperature for 3˜5 hours under second thermal processing temperature of 1,700˜2,500° C., vacuum level of 3˜5 mmHg, and heat rising rate of 20˜100° C./hr. Moreover, the friction substance produced by the above-mentioned two methods can be used for any one or all of the clutch facing, friction pad, and press pad on which friction is made in the clutch. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a disassembled disk assembly of the clutch for transmission power according to the present invention. FIG. 2 is a cross sectional view showing an assembled disk assembly of the clutch for transmission power of FIG. 1. FIG. 3 is a cross sectional view showing a half of the clutch for transmission power which is installed with a disk assembly according to the present invention. FIG. 4 is a flowchart showing a method of producing the friction substance for the clutch in a two-dimensional preform according to the present invention. FIG. 5 is a flowchart showing a method of producing the friction substance for the clutch in a three-dimensional preform according to the present invention. FIG. 6 is a horsepower-torque graph of the clutch wherein a conventional organic facing is provided with. FIG. 7 is a horsepower-torque graph of the clutch wherein a conventional copper-ceramic facing is provided with. FIG. 8 is a horsepower-torque graph of the clutch wherein a carbon-carbon composition facing according to the present invention is provided with. FIG. 9 is a graph showing the response characteristic of gear shift for the clutch installed with a clutch disk assembly according to the present invention. DETAILED DESCRIPTION OF THE INVENTION The clutch for transmission power according to the present invention includes a simplified spline hub and a clutch facing made of carbon-carbon composition having high performance in shock absorption capability. It can be simplified as a single part by the structure of a spline hub for improving assemblability and reducing weight, thereby improving transmission power efficiency of engine. Moreover, the clutch facing made of carbon-carbon composition replaces the function of shock absorption, which was conventionally undertaken by coil spring or the like that was installed in a spline hub so that soft start can be attainable for automobiles. Furthermore, since fading is not generated due to its excellent properties of friction, abrasion and thermal shock resistance at high temperature, sufficient power can be transmitted, thereby enhancing its marketability and durability. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The clutch disk assembly according to the present invention includes a clutch facing 10 made of carbon-carbon composition wherein a center hole 11 is formed in the middle thereof and a plurality of the first fastening holes along the outer circumference of the center hole 11 are formed as shown in FIG. 1 and FIG. 2. The clutch facing 10 can be divided into a body portion 10a and a contacting portion 10b being integrated. The body portion 10a is a portion to be combined with a spline hub 20 to be described later, and the contacting portion 10b is a portion to be contacted with a friction pad 71 and a press pad 61 to be described later. Accordingly, body portion 10a and contacting portion 10b can be separately produced for combination and use, if required. Furthermore, it has a spline hub 20 wherein a boss 22 being overlapped with one side of the clutch facing 10 and inserted into the center hole 11 is formed on one side, and a plurality of the second fastening holes 23 being communicated with a plurality of the first fastening holes 12 are formed along the circumference. Moreover, a plurality of spline grooves 21 are formed in the vertical direction of the spline hub on the inner diameter of a bore which is formed in the middle of the spline hub 20. Furthermore, a retainer ring 30 being overlapped with the first fastening holes 12 is formed on the other side of the clutch facing 10. A plurality of the third fastening holes 31 being communicated with the first fastening holes 12 are formed on this retainer ring 30. Therefore, first fastening holes 12, second fastening holes 23 and third fastening holes 31 are communicated with one another for combining clutch facing 10, spline hub 20 and retainer ring 30 at the same time by a combining means. This combining means comprises a plurality of bolts 40 as shown in the drawing, and other types of combining means such as rivet or the like can be used if required. Each of fastening holes 12, 23 and 31 is formed with 10˜20 in number. On the other hand, the clutch facing 10 made of carbon composition is formed with carbon-carbon composition which is composed of 20˜75 weight % of carbon fiber and 25˜80 weight % of pitch, or with carbon-silicon carbide composition which is composed of 3˜20 weight % of silicon, 10˜60 weight % of silicon carbide, and 20˜87 weight % of pitch-containing carbon. Moreover, the carbon fiber is formed with a single fiber or by stacking continuously woven carbon fabrics. The clutch disk assembly according to the present invention is installed within clutch cover 50 as shown in FIG. 3. Furthermore, press plate 60 provided with press pad 61 is positioned on the right of the clutch facing 10 which is installed within clutch cover 50, and flywheel 70 provided with a friction pad 71 is positioned on the left. Also, press pad 61 and friction pad 71 can be made of carbon composition. For installing friction pad 71 made of carbon composition, a groove 72 at the depth of 5˜8 mm is formed on the surface of flywheel 70 on which each of them is provided, and adhesive agent is coated with a brush at the depth of 0.2˜0.6 mm on this groove 72, and then the coated adhesive agent is dried within the range of 70˜80° C. for 20˜30 minutes. Then, friction pad 71 is installed on each groove 72 by pressurizing with 350˜1,000 KN/m2 and holding it for curing within the range of 150˜230° C. for 15˜30 minutes, or it is fastened by bolts. This installation can also be used for press pad 61 made of carbon composition. In the present embodiment, it is illustrated that press pad 61 is attached to press plate 60 without providing a separate groove. On the other hand, in another embodiment that is not shown in the drawing, it can be provided by installing a cushion plate on the spline hub, and bonding a clutch facing made of carbon composition to this cushion plate as used for conventional structure of a clutch disk. At this time, clutch facing is made of a master form or 3˜6 pads, and the cushion plate of spline hub is also formed with a master form or by dividing into 3˜6 pads in paddle type, and a clutch facing made of carbon composition is bonded with adhesive agent. Here, a separate cushion absorption structure is not required for the cushion plate as used for conventional clutches. For a bonding method, moreover, bonding is performed by cleaning the cushion plate and clutch facing made of carbon composition with alcohol and drying at about 80° C. for 20 minutes, and then coating the cushion plate and carbon-carbon composition with adhesive agent at 0.2˜0.6 mm wet thickness and drying within the range of 70˜80° C. for 20˜30 minutes, and then pressurizing at the press pressure of 350˜1,000 KN/m2, heating within the range of 150˜230° C. and holding it for 5˜30 minutes for curing. Hereinafter, an embodiment for a method of manufacturing the friction substance for a clutch, which is used for a clutch facing, a friction pad, a press pad in clutches, will be described. For the method of manufacturing the friction substance for a clutch according to the present invention, PAN (polyacrylonitrile)-based carbon fiber is used. The friction substance can be manufactured by the following processes, more particularly it can be manufactured by two-dimensional and three-dimensional forms. First, as shown in FIG. 4, the method of manufacturing a two-dimensional preform includes the steps of performing a first thermal treatment wherein carbon fiber is thermally treated for graphitization at a first thermal processing temperature (S100) for improving thermal conductivity, producing a prepreg wherein resin is sprayed on carbon fiber fabric for forming the prepreg (S110), producing a preform wherein carbon fiber and resin are stacked on the prepreg to form the preform (S120), producing a mold wherein the mold is formed by using a press on the preform (S130), and performing a second thermal treatment wherein the mold is thermally treated at a second thermal processing temperature (S150). Furthermore, carbon-silicon carbide composition can be manufactured by performing a silicon powder addition process (S200) and a vacuum heating process (S210) additionally after performing the above-mentioned processes. Such divided processes will be described separately as the steps S1 and S2 in FIG. 4. First, the first thermal treatment process S100 for manufacturing carbon-carbon composition as the step S1 is a graphitization process to improve the thermal conductivity of carbon fiber by performing a thermal treatment at high temperature on PAN-based carbon fiber at first thermal treatment temperature of 2,000˜3,000° C. Moreover, the carbon fiber is formed with a single fiber or by stacking continuously woven carbon fabrics, and a cutting process for cutting the thermally treated carbon fiber at the length of 200˜2,000 μm is performed using fiber cutting machine when carbon fiber is used for a single fiber. In the prepreg producing process S110, a prepreg is produced by uniformly scattering resin such as pitch or resin which is crushed by a crusher at the fineness of 0.5˜10 μm on the carbon fiber, and heating it within the range of 180˜270° C. In the preform producing process S120, a preform is produced by uniformly stacking the cut carbon fiber and the crushed resin on the prepreg. In addition, a required mold is produced after heating the preform within the range of 200˜300° C. during the mold producing process S130, and a densification process S140 for densifying the mold can be added separately after the mold producing process S130. In the densification process S140, a mold is densified at a predetermined density by pressurizing at the carbonizing pressure of 50˜2,000 kg/cm2 within the range of 750˜1,400° C. for 3˜5 hours, and performing a carbonization/impregnation process. Here, the predetermined density thereof is 1.3˜1.6 g/cm3. Next, the second thermal treatment process S150 is performed at the maximum temperature for 3˜5 hours under second thermal processing temperature of 1,700˜2,500° C., vacuum level of 3˜5 mmHg, and heat rising rate of 20˜100° C./hr. On the other hand, the step S2 for manufacturing carbon-silicon carbide composition by adding silicon powder to the surrounding of low density carbon-carbon composition which was produced using the above-mentioned method can be applied. For this, silicon powder addition process S200 and vacuum heating process S210 can be applied additionally. Silicon powder 0.2˜5.0 times heavier than the mold in weight ratio is added to the surrounding of the mold during silicon powder addition process S200, and carbon-silicon carbide composition is produced by increasing the temperature within the range of 1,450° C.˜2,200° C. and maintaining it for 0.1˜5.0 hours under the vacuum atmosphere during vacuum heating process S210. The carbon-silicon carbide composition produced in this step is composed of 3˜25 weight % of silicon, 10˜65 weight % of silicon carbide, and 10˜80 weight % of carbon. Next, as shown in FIG. 5, the manufacturing method by using a three-dimensional preform includes the steps of heating for creating thermal gradient between the inside and outside of the preform by mounting a heating element on the middle of the three-dimensional preform woven with carbon fiber (S300), infiltrating reaction gas, such as methane, ethane, propane, butane, pentane or hexane, containing 1˜6 carbons per molecule inside the reactor (S310), producing a mold by performing reaction under a predetermined condition (S320), and performing a thermal treatment on the mold (S330). Here, the three-dimensional preform is produced by weaving carbon rods having the diameter of 1˜2 mm which have been prepared by a drawn molding process, and it is manufactured and marketed by companies such as ASNC (American Structure Needing Co.) in U.S. Moreover, thermal gradient heating process S300 and reaction gas infiltration process S310 can be referred to as thermal gradient chemical vapor infiltration. As for the thermal gradient chemical vapor infiltration, it is performed on reaction material under the condition where in the thermal gradient is created between the inside and outside of the preform by providing a heating element in the middle of the carbon fiber preform that is mounted inside the reactor and heating by this heating element to create thermal conduction toward the outside from the middle of the preform. According to this method of thermal gradient chemical vapor infiltration, density as well as thermal conductivity thereof increases in the middle of the preform by causing thermal decomposition of gas for vapor infiltration in the middle of the preform where the reaction temperature is arrived at relatively sooner. As a result, due to the thermal conductivity, infiltration is finally performed on the surface of the preform while the gas reaction area moves toward the surface by expanding the range of the reaction temperature gradually toward the surface from the middle. Furthermore, mold producing process S320 is performed under heat rising rate of 10˜20° C./min, reaction temperature of 700˜1200° C., reaction gas concentration of 10˜100%, and reaction pressure of 250˜1,500 mbar; moreover, thermal treatment process S330 is performed at the maximum temperature for 3˜5 hours under second thermal processing temperature of 1,700˜2,500° C., vacuum level of 3˜5 mmHg, and heat rising rate of 20˜100° C./hr. Hereinafter, the clutch facing formed with carbon composition according to the present invention and the clutch facing formed with conventional methods will be compared. In the following graphs, the results are shown by testing twice the clutches which are installed respectively with each type of clutch facing. FIG. 6 is a graph showing the test result wherein the clutch installed with an organic-based facing is provided on chassis power testing machine. The horsepower (left side) and torque (right side) are plotted according to the RPM (axis of abscissa). As shown in the drawing, it is seen that this clutch is soft at the starting time but slippery movement occurs at abrupt acceleration or 2,800˜3,800 RPM, thereby decreasing the efficiency of power transmission from the driving shaft flywheel to gear shaft by 20˜30%. FIG. 7 is a horsepower-torque graph of the clutch wherein a conventional copper-ceramic sinter facing is provided with. The output response characteristic is good at abrupt acceleration, but it has a disadvantage that soft start can not be attainable for automobiles, so drivers feel tired easily due to abrupt friction shock that occurs at the starting time of 2,100˜2,700 RPM. FIG. 8 is a graph showing the result wherein the clutch installed with a carbon composition clutch facing according to the present invention is tested for the maximum torque at 4,500˜6,000 RPM, and it is seen that torque is 44.4 kg-M and horse power is 331.2 PS at 4,800 RPM. The automobile installed with a clutch having the clutch disk assembly according to the present invention can start softly; besides, it is seen that slippery does not occur at abrupt acceleration and power transmission from driving shaft flywheel to gear shaft is excellent. So it can be applied even at high torque values. FIG. 9 is a graph showing the response characteristic of gear shift for the clutch installed with a clutch disk assembly according to the present invention. It is seen that response characteristic is excellent since power transmission is soft without having loss or shock of power transmission as well as impact position while shifting to the second level from the first level at the starting time. The characteristic of each clutch facing will be described in TABLE 1. TABLE 1 Clutch Organic- Copper-Ceramic Carbon—Carbon Characteristic based Sinter Composition Friction Coefficient 0.10˜0.30 0.25˜0.40 0.25˜0.45 Max. Temperature 175˜300 260˜400 350˜450 (° C.) Torque (kg-m) 17˜28 32˜40 44.4 Horse Power (Ps) 200˜300 270˜300 331.2 Press Plate Load (kgf) 440˜480 1000 1000 As shown in TABLE 1, friction coefficient shows similar tendency for both copper-ceramic sinter and carbon-carbon composition, and temperature shows higher for carbon-carbon composition when compared to the friction coefficient. Moreover, organic-based material was broken due to frictional heat and abrasion at the press plate load of 1000 kgf. In other words, it is seen that the carbon composition friction material used for clutch disk assembly shows a remarkably improved performance against organic-based material, and a slightly superior performance compared to copper-ceramic sinter material. It should be understood that a person having ordinary skill in the art to which the invention pertains can modify some of the embodiments with regard to the clutch for transmission power and the method of manufacturing the friction substance for the clutch according to the present invention as mentioned above. However, if such modified embodiments include essential elements of the invention it should be regarded that they are all within technical scope of the invention; moreover, technical idea of the invention should not be restricted by the elements illustrated in the embodiments. As described above, the clutch disk assembly and the method of manufacturing the friction substance for clutch according to the invention can improve assemblability and reduce weight by simplifying into a single part without using shock absorbing apparatus such as coil spring or the like on clutch disk assembly. In addition, the power transmission of an engine can be improved, and also it has an effect that an automobile can start softly and slippery does not occur even at abrupt acceleration by providing with carbon-carbon composition or carbon-silicon carbide composition having excellent shock absorption function. | <SOH> BACKGROUND OF THE INVENTION <EOH>In general, a clutch characteristically requires response characteristics, such as soft gearshift and fast and high transmission power, as a mechanical element for transmitting power wherein a driving shaft and a driven shaft are connected to each other in mechanical devices. This clutch can be used for various industrial areas such as automobiles, motorcycles, industrial machines, presses, ships, etc. In particular, the clutch used for automobile is designed to allow slippery movement by half clutch operation to attain soft start for vehicles. Accordingly, high-temperature frictional heat can be created within the range of 200° C.˜600° C. with this half clutch operation. As a result, the clutch undergoes phenomena such as thermal load and fatigue, dynamic load by intermittent contact torque of the clutch caused by friction, and deterioration of clutch cover and disk at high temperature due to friction over the areas such as flywheel, clutch disk, press plate, etc. since high torque power is transmitted by friction. Caused by this phenomena, fatigue, crack or the like are created by thermal load and dynamic load, and also fading is created due to the reduced friction coefficient at high temperature as well as at high RPM (revolutions per minute). This is the main cause for reducing the life of a clutch. Various studies for solving the above-mentioned problem have been progressed until now. As for known solutions for these problems, there are a clutch cushion plate, a rubber damper, wave spring, etc. which are used for the shock absorption structure, and also a method of providing ventilation grooves at clutch disk or providing holes at flywheel or press plate was developed as cooling system. | <SOH> SUMMARY OF THE INVENTION <EOH>It is an object of the invention to provide a clutch for transmission power for minimizing the damage on its life span which is induced by the friction at high temperature by providing the material of clutch facing with carbon-carbon composition having a simple structure without using a cushion plate, a rubber damper, wave spring or cooling system. It is another object of the invention to provide a method of manufacturing friction substance for the clutch wherein the friction substance that is used for the clutch such as clutch facing, press pad and friction pad can be produced with carbon-carbon composition. A clutch for transmission power to achieve the first object of the invention includes a flywheel, a clutch cover and a clutch disk assembly positioning between the flywheel and the clutch cover, wherein the clutch disk assembly includes a clutch facing having the body portion formed with a center hole in the middle thereof, and a contacting portion wherein one side thereof faces the friction pad at the flywheel side and the other side thereof faces the press plate of the clutch cover, and the portion facing each other between the friction pad and the press plate is made of carbon-carbon composition; a spline hub being overlapped with one side of the clutch facing wherein a spline groove is formed in the inner diameter thereof; and a combining means for combining the clutch facing with the spline hub. Moreover, the spline hub is formed with a boss for inserting into the center hole of the clutch facing, and the combining means includes a retainer ring being overlapped with the other side of the clutch facing; and a fastening member by passing through the clutch facing, the spline hub and the retainer ring. Here, the fastening member includes either bolt or rivet selectively. On the other hand, the contacting portion is formed with carbon-carbon composition which is composed of 20˜75 weight % of carbon fiber and 25˜80 weight % of pitch. Another aspect of the invention is that the contacting portion is made of carbon-silicon carbide which is composed of 3˜20 weight % of silicon, 10˜60 weight % of silicon carbide, and 20˜87 weight % of pitch-containing carbon. Furthermore, the carbon fiber is a single fiber, or it is formed by continuously woven carbon fabrics. In another aspect of the invention, moreover, the body portion is integrally formed with the contacting portion by using the same carbon-carbon composition material which is used for the contacting portion. Still another aspect of the invention is that the press plate is provided with the press pad adjoining the clutch facing, and the press pad and the friction pad are formed with the same carbon-carbon composition which is used for the contacting portion. The method of manufacturing the friction substance for the clutch to achieve the second object of the invention can be divided into two steps. The first step is to produce a two-dimensional preform, and the second step is to produce a three-dimensional preform. The method of producing a two-dimensional preform includes the steps of performing a first thermal treatment wherein carbon fiber is thermally treated for graphitization at a first thermal processing temperature, producing a prepreg wherein resin is sprayed on carbon fiber fabrics to form the prepreg, producing a preform wherein carbon fiber and resin are stacked on the prepreg to form the preform, producing a mold wherein the mold is formed by using a press on the preform, and performing a second thermal treatment wherein the mold is thermally treated at a second thermal processing temperature. Another aspect of the invention further includes the step of cutting the thermally treated carbon fiber at the length of 200˜2,000 μm by using fiber-cutting machine between the first thermal treatment process and the prepreg producing process. Still another aspect of the invention includes a densification process for densifying the mold at a predetermined density using a carbonization/impregnation process for pressurizing at the carbonizing pressure of 50˜2,000 kg/cm 2 within the range of 750˜1,400° C. for 3˜5 hours between the mold producing process and the second thermal treatment process. Here, the predetermined density is 1.3˜1.6 g/cm 3 . In still further aspect of the invention, the first thermal processing temperature is 2,000˜3,000° C. during the first thermal treatment process. In the step of producing a mold, moreover, the mold is composed of 20˜75 weight % of carbon fiber and 25˜80 weight % of the resin, and molded by heating within the range of 200˜300° C. at the press. In another aspect of the invention, the second thermal treatment process is performed at the maximum temperature for 3˜5 hours under second thermal processing temperature of 1,700˜2,500° C., vacuum level of 3˜5 mmHg, and heat rising rate of 20˜100° C./hr. In still another aspect of the invention, it further includes the steps of performing a silicon powder addition process by adding silicon powder to the mold after the second thermal treatment process, and performing a vacuum heating process for increasing the temperature within the range of 1,450° C.˜2,200° C. and maintaining it for 0.1˜5.0 hours under the vacuum atmosphere, and silicon powder 0.2˜5.0 times heavier than the mold in weight ratio is added during the silicon powder addition process. After finishing the vacuum heating process, the mold is composed of 3˜25 weight % of silicon, 10˜65 weight % of silicon carbide, and 10˜80 weight % of carbon. The method of producing a three-dimensional preform includes the steps of heating for creating a thermal gradient between the inside and outside of the preform by mounting a heating element on the three-dimensional preform, infiltrating reaction gas containing 1˜6 carbons per molecule inside the reactor, producing a mold by performing reaction under a predetermined condition, and performing a thermal treatment on the mold. Furthermore, the predetermined condition is heat rising rate of 10˜20° C./min, reaction temperature of 700˜1200° C., reaction gas concentration of 10˜100%, and reaction pressure of 250˜1,500 mbar, and the thermal treatment process is performed at the maximum temperature for 3˜5 hours under second thermal processing temperature of 1,700˜2,500° C., vacuum level of 3˜5 mmHg, and heat rising rate of 20˜100° C./hr. Moreover, the friction substance produced by the above-mentioned two methods can be used for any one or all of the clutch facing, friction pad, and press pad on which friction is made in the clutch. | 20040415 | 20060912 | 20050526 | 69971.0 | 0 | LORENCE, RICHARD M | CLUTCH FOR TRANSMISSION POWER AND METHOD OF MANUFACTURING FRICTION SUBSTANCE FOR THE CLUTCH | SMALL | 0 | ACCEPTED | 2,004 |
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10,825,345 | ACCEPTED | System and method for computer cluster virtualization using dynamic boot images and virtual disk | A method for computer cluster virtualization includes selecting a distributed application. A policy associated with the distributed application is retrieved. One of a plurality of nodes is dynamically selected. Then, a boot image of the selected node is reset based, at least in part, on the retrieved policy, with the boot image being compatible with the distributed application. Then, a virtual disk image is associated with the node. At least a portion of the distributed application is then executed on the reset node using the associated virtual disk image. | 1. A method for computer cluster virtualization comprises: selecting a distributed application; retrieving a policy associated with the distributed application; dynamically selecting one of a plurality of nodes; resetting a boot image of the selected node based, at least in part, on the retrieved policy, the boot image compatible with the distributed application; and associating a virtual disk image with the selected node based, at least in part, on the retrieved policy; and executing at least a portion of the distributed application on the reset node using the associated virtual disk image. 2. The method of claim 1, the application executing on a subset of the plurality of nodes and the method further comprising: comparing the subset of nodes with the retrieved policy; and selecting one of a plurality of compatible boot images based on the comparison. 3. The method of claim 2, wherein comparing the subset of nodes with the retrieved policy comprises: determining a count of nodes in the subset; and selecting the boot image based on a link in the policy and the count of nodes. 4. The method of claim 2, each of the subset of nodes associated with one of the plurality of compatible boot images. 5. The method of claim 1, wherein dynamically selecting one of the plurality of nodes comprises: determining if one or more of the plurality of nodes is unutilized by a second distributed application; and in response to at least one of the nodes being unutilized, selecting one of the unutilized nodes. 6. The method of claim 5, in response to none of the nodes being unutilized, further comprising selecting one of the nodes utilized by the second distributed application based on one or more of the following: the retrieved policy; low utilization of the selected node; priority of the selected distributed application; and compatibility of the selected node with the selected distributed application. 7. The method of claim 6, wherein resetting the boot image of the selected node comprises: automatically shutting down the selected node; resetting the boot image of the selected node; and restarting the selected node using the reset boot image. 8. The method of claim 7, further comprising terminating any processes associated with the second distributed application prior to shutting down the node. 9. The method of claim 1, the policy comprising a plurality of links to boot images, each link associated with one of a count of nodes compatible with the distributed application. 10. The method of claim 1, the policy comprising one or more parameters for determining the timing of the selection of the node. 11. The method of claim 1, the boot image comprising a remote boot image stored in a Storage Area Network (SAN). 12. The method of claim 1, the node associated with a first boot image prior to the reset and associated with a second boot image from the reset, the first and second boot image differing in at least one of the following characteristics: operating system; system configuration; and distributed application parameters. 13. The method of claim 1, further comprising: determining that one of the plurality of nodes failed, the failed node executing at least a portion of the selected distributed application; and wherein selecting one of the plurality of nodes comprises selecting one of the remaining nodes in response to the failure. 14. The method of claim 1, each of the plurality of nodes comprising the same processor architecture. 15. The method of claim 1, wherein selecting one of the plurality of nodes comprises selecting one of the plurality of nodes at a predetermined time. 16. Software for computer cluster virtualization operable to: select a distributed application; retrieve a policy associated with the distributed application; dynamically select one of a plurality of nodes; reset a boot image of the selected node based, at least in part, on the retrieved policy, the boot image compatible with the distributed application; and associate a virtual disk image with the selected node based, at least in part, on the retrieved policy; and execute at least a portion of the distributed application on the reset node using the associated virtual disk image. 17. The software of claim 16, the application executing on a subset of the plurality of nodes and the software further operable to: compare the subset of nodes with the retrieved policy; and select one of a plurality of compatible boot images based on the comparison. 18. The software of claim 17, wherein the software operable to compare the subset of nodes with the retrieved policy comprises software operable to: determine a count of nodes in the subset; and select the boot image based on a link in the policy and the count of nodes. 19. The software of claim 17, each of the subset of nodes associated with one of the plurality of compatible boot images. 20. The software of claim 16, wherein the software operable to dynamically select one of the plurality of nodes comprises software operable to: determine if one or more of the plurality of nodes is unutilized by a second distributed application; and in response to at least one of the nodes being unutilized, select one of the unutilized nodes. 21. The software of claim 20, in response to none of the nodes being unutilized, further operable to select one of the nodes utilized by the second distributed application based on one or more of the following: the retrieved policy; low utilization of the selected node; priority of the selected distributed application; and compatibility of the selected node with the selected distributed application. 22. The software of claim 21, wherein the software operable to reset the boot image of the selected node comprises software operable to: automatically shut down the selected node; reset the boot image of the selected node; and restart the selected node using the reset boot image. 23. The software of claim 22, further operable to terminate any processes associated with the second distributed application prior to shutting down the node. 24. The software of claim 16, the policy comprising a plurality of links to boot images, each link associated with one of a count of nodes compatible with the distributed application. 25. The software of claim 16, the policy comprising one or more parameters for determining the timing of the selection of the node. 26. The software of claim 16, the boot image comprising a remote boot image stored in a Storage Area Network (SAN). 27. The software of claim 16, the node associated with a first boot image prior to the reset and associated with a second boot image from the reset, the first and second boot image differing in at least one of the following characteristics: operating system; system configuration; and distributed application parameters. 28. The software of claim 16, further operable to: determine that one of the plurality of nodes failed, the failed node executing at least a portion of the selected distributed application; and wherein the software operable to select one of the plurality of nodes comprises software operable to select one of the remaining nodes in response to the failure. 29. The software of claim 16, each of the plurality of nodes comprising the same processor architecture. 30. The software of claim 16, wherein the software operable to select one of the plurality of nodes comprises software operable to select one of the plurality of nodes at a predetermined time. 31. A system for computer cluster virtualization comprises: a plurality of computing nodes; and a management node operable to: select a distributed application; retrieve a policy associated with the distributed application; dynamically select one of a plurality of nodes; reset a boot image of the selected node based, at least in part, on the retrieved policy, the boot image compatible with the distributed application; and associate a virtual disk image with the selected node based, at least in part, on the retrieved policy; and execute at least a portion of the distributed application on the reset node using the associated virtual disk image. 32. The system of claim 31, the application executing on a subset of the plurality of nodes and the management node further operable to: compare the subset of nodes with the retrieved policy; and select one of a plurality of compatible boot images based on the comparison. 33. The system of claim 32, wherein the management node operable to compare the subset of nodes with the retrieved policy comprises the management node operable to: determine a count of nodes in the subset; and select the boot image based on a link in the policy and the count of nodes. 34. The system of claim 32, each of the subset of nodes associated with one of the plurality of compatible boot images. 35. The system of claim 31, wherein the management node operable to dynamically select one of the plurality of nodes comprises the management node operable to: determine if one or more of the plurality of nodes is unutilized by a second distributed application; and in response to at least one of the nodes being unutilized, select one of the unutilized nodes. 36. The system of claim 35, in response to none of the nodes being unutilized, selecting one of the nodes utilized by the second distributed application based on one or more of the following: the retrieved policy; low utilization of the selected node; priority of the selected distributed application; and compatibility of the selected node with the selected distributed application. 37. The system of claim 36, wherein the management node operable to reset the boot image of the selected node comprises the management node operable to: automatically shut down the selected node; reset the boot image of the selected node; and restart the selected node using the reset boot image. 38. The system of claim 37, the management node further operable to terminate any processes associated with the second distributed application prior to shutting down the node. 39. The system of claim 31, the policy comprising a plurality of links to boot images, each link associated with one of a count of nodes compatible with the distributed application. 40. The system of claim 31, the policy comprising one or more parameters for determining the timing of the selection of the node. 41. The system of claim 31, the boot image comprising a remote boot image stored in a Storage Area Network (SAN). 42. The system of claim 31, the node associated with a first boot image prior to the reset and associated with a second boot image from the reset, the first and second boot image differing in at least one of the following characteristics: operating system; system configuration; and distributed application parameters. 43. The system of claim 31, the management node further operable to: determine that one of the plurality of nodes failed, the failed node executing at least a portion of the selected distributed application; and wherein the management node operable to select one of the plurality of nodes comprises the management node operable to select one of the remaining nodes in response to the failure. 44. The system of claim 31, each of the plurality of nodes comprising the same processor architecture. 45. The system of claim 31, wherein the management node operable to select one of the plurality of nodes comprises the management node operable to select one of the plurality of nodes at a predetermined time. | BACKGROUND OF THE INVENTION Typically, enterprise applications are executed on dedicated compute resources. Often, an enterprise will include a variety of computing environments for different instances of the application such as production, test, and development. These multiple computing environments are typically the same size and capacity as the live or production instance. Moreover, the non-production environments are frequently idle for extended periods of time. This normally results in large amounts of wasted computing resources and labor expense in maintaining and administering these various environments. Currently, enterprises may use provisioning as an attempt to address these issues. Generally, provisioning is the process of instantiating compute resources to the enterprise application by copying the local disk from a repository to the resource. The resource is then booted with the provisioned operating system and software through a process that normally takes over ten minutes. SUMMARY OF THE INVENTION This disclosure provides a system and method for computer cluster virtualization that includes selecting a distributed application. A policy associated with the distributed application is retrieved. One of a plurality of nodes is dynamically selected, possibly based on the policy. Then, a boot image of the selected node is reset based, at least in part, on the retrieved policy, with the boot image being compatible with the distributed application. Then, a virtual disk image is associated with the node. At least a portion of the distributed application is then executed on the reset node using the associated virtual disk image. The invention has several important technical advantages. For example, one possible advantage of the present invention is that it allows for computing nodes to be reprovisioned on-the-fly to become a member of a virtual cluster for a distributed application, thereby possibly reducing provisioning times to fifteen seconds or less. Another possible advantage of the present disclosure may be a reduction in Information Technology (IT) hardware and maintenance costs by at least thirty percent. Moreover, when an application is not at a peak processing period, idles nodes of that application may be dynamically reallocated or reprovisioned to other distributed applications. Yet another possible advantage is that it provides centralized capacity planning, performance monitoring, and simplified administration. Further, the present invention may allow for better node failure management. Various embodiments of the invention may have none, some, or all of these advantages. Other technical advantages of the present invention will be readily apparent to one skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present disclosure and its advantages, reference is now made to the following descriptions, taken in conjunction with the accompanying drawings, in which: FIG. 1 illustrates an example distributed system providing dynamic booting in accordance with one embodiment of the present disclosure; and FIG. 2 illustrates an example method for dynamically rebooting a node within one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating a distributed computing system 100 for executing software applications 114 and processes using dynamic boot images 131. Generally, system 100 is a scalable distributed computing environment for enterprise or other distributed applications. System 100 provides a scalable, fault-tolerant computing environment, which can dynamically grow based on computing needs and can simultaneously provide computing resources to multiple applications 114 through providing each application 114 with its own scalable virtual cluster. For example, system 100 may include server 102 that is connected, through network 116 to one or more administration workstations or local clients 120. But system 100 may alternatively be a standalone computing environment or any other suitable environment. In short, system 100 is any computing environment that automatically allows nodes 108 to be dynamically allocated on-the-fly as application 114 requirements, parameters, and processing needs change. The term “dynamically,” as used herein, generally means that certain processing is determined, at least in part, at run-time based on one or more variables. The term “automatically,” as used herein, generally means that the appropriate processing is substantially performed by at least part of system 100. It should be understood that “automatically” further contemplates any suitable user or administrator interaction with system 100 without departing from the scope of this disclosure. Server 102 comprises any local or distributed computer operable to execute a plurality of applications 114 across one or nodes 108. Generally, server 102 comprises a distributed computer such as a rack-mounted server, blade server, or other distributed server. Nodes 108 comprise any computer or processing device such as, for example, blades, general-purpose personal computers (PC), Macintoshes, workstations, Unix-based computers, or any other suitable devices. Generally, FIG. 1 provides merely one example of computers or blades that may be used with the disclosure. For example, although FIG. 1 illustrates one blade server 102 that may be used with the disclosure, server 102 can be implemented using computers other than servers, as well as a server pool. In other words, the present disclosure contemplates computers other than general purpose computers as well as computers without conventional operating systems. As used in this document, the term “computer” is intended to encompass a personal computer, workstation, network computer, or any other suitable processing device. Server 102, or the component nodes 108, may be adapted to execute any operating system including Linux, UNIX, Windows Server, or any other suitable operating system. According to one embodiment, server 102 may also include or be communicably coupled with a remote web server. Illustrated server 102 includes a management node 104 communicably coupled with a plurality of nodes 108 and operable to execute dynamic boot engine 105. But it will be understood that server 102 and nodes 108 may not include all of the illustrated components. Management node 104 comprises at least one blade or computing device substantially dedicated to managing server 102 or assisting an administrator. For example, management node 104 may comprise two hot-swappable blades, with one of the two blades or rack-mounted servers being redundant (such as an active/passive configuration). Dynamic boot engine 105 could include any hardware, software, firmware, or combination thereof operable to dynamically allocate and manage nodes 108 and execute applications 114 using virtual clusters of nodes 108 (or application environments). For example, dynamic boot engine 105 may be written or described in any appropriate computer language including C, C++, Java, Visual Basic, assembler, any suitable version of 4GL, and others or any combination thereof. It will be understood that while dynamic boot engine 105 is illustrated in FIG. 1 as a single multi-tasked module, the features and functionality performed by this engine may be performed by multiple modules such as, for example, a physical layer module, a virtual layer module, a job scheduler, and a presentation engine. Moreover, dynamic boot engine 105 may be a child or sub-module of another software module without departing from the scope of this disclosure. Therefore, dynamic boot engine 105 comprises one or more software modules operable to intelligently manage nodes 108 and applications 114 based on policies 132. Generally, dynamic boot engine 105 manages one or more applications 114 by starting and stopping application environments on the individual nodes 108. For example, dynamic boot engine 105 may reset the particular node 108 with a different boot image 131 from boot image file 130, which is specific to or compatible with the desired application environment. In other words, dynamic boot engine 105 supports dynamically booting any suitable application environment on any controlled node 108. Accordingly, dynamic boot engine 105 may also support dynamically setting IP or MAC addresses for the public IP interface on any controlled computer. Dynamic boot engine 105 may also boot any node 108 directly from the network using a network boot protocol or by booting from attached disk storage. Dynamic boot engine 105 may also utilize high speed network access to a virtual local disk image containing the operating system, services, and applications for any controlled computer. It will be understood that dynamic boot engine 105 may start up or shut down application environments based on calendar date and times or using any other predetermined parameter. Dynamic boot engine 105 may also support various fault tolerance and recovery techniques. For example, boot engine 105 may automatically recover server 102 from single hardware component failures by automatically replacing and dynamically rebooting a replacement node 108 for the failed node 108. Moreover, installing a new node 108 may be facilitated because of dynamic boot engine's 105 ability to automatically recognize the new node 108 and do any required configuration, resetting, or booting. Nodes 108 comprises any computer, blade, or server operable to execute at least a portion (such as a task or process) of application 114. Illustrated node 108 includes, at a high level, memory 109 and processor 110. Memory 109 may include any memory or database module and may take the form of volatile or non-volatile memory including, without limitation, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), removable media, or any other suitable local or remote memory component. Memory 109 may include any of a variety of local information. Node 108 also includes processor 110. Processor 110 executes instructions and manipulates data to perform the operations of server 102 such as, for example, a central processing unit (CPU) or field programmable gate array (FPGA). Although FIG. 1 illustrates a single processor 110 in each node 108, multiple processors 110 may be used according to particular needs and reference to processor 110 is meant to include multiple processors 110 where applicable. Processor 110 may include any pointer to a boot image such as, for example, Electronically Erasable Programmable Read-Only Memory (EEPROM) 111. But it will be understood that node 108 may comprise any number of components, configured in any appropriate fashion, without departing from the scope of this disclosure. Node 108 may also include one or more local hard drives for the purposes of providing local temporary file space and virtual memory swap space. Application 114 may comprise any enterprise or distributed application such as, for example, a database management system (DBMS), financial software, and others. Typically, application 114 is comprised of software written in any suitable language and operable to perform any data processing. But unconventional applications are also within the scope of this disclosure. Applications 114 may run in an application environment, or virtual cluster, which logically defines the environment for application execution. In one embodiment, an application environment comprises i) name and description of the application environment; ii) minimum/maximum number of nodes 108; iii) software configuration information, such as operating system software version and application 114 software version; and iv) hardware configuration of each node 108 such as boot image, hostname and IP address, custom configuration applied after node 108 booting, virtual local disk image, local file systems, file systems to mount, and network configuration. But it will be understood that any suitable parameter, variable, or characteristic may be used to assist dynamic boot engine 105 with defining, locating, and processing the application environment. For example, the application environment may also include information on application 114 startup, shutdown, and health monitoring. Server 102 may include interface 115 for communicating with other computer systems, such as client 120, over network 116 in a client-server or other distributed environment. In certain embodiments, server 102 receives boot images 131, virtual local disk images 134, policies 132, or application data 140 from network 116 for storage or processing via high-speed interface 115. Generally, interface 115 comprises logic encoded in software and/or hardware in a suitable combination and operable to communicate with network 116. More specifically, interface 115 may comprise software supporting one or more communications protocols associated with communications network 116 or hardware operable to communicate physical signals. Network 116 facilitates wireless or wireline communication between computer server 102 and any other computer, such as clients 120. Indeed, while illustrated as residing between server 102 and client 120, network 116 may also reside between various nodes 108 without departing from the scope of the disclosure. In other words, network 116 encompasses any network, networks, or sub-network operable to facilitate communications between various computing components. Network 116 may communicate, for example, Internet Protocol (IP) packets, Frame Relay frames, Asynchronous Transfer Mode (ATM) cells, voice, video, data, and other suitable information between network addresses. Network 116 may also process and route data packets according to any other suitable communication protocol, for example, InfiniBand (IB), Gigabit Ethernet (GE), or FibreChannel (FC). Data packets are typically used to transport data within application data 140. A data packet may include a header that has a source identifier and a destination identifier. The source identifier, for example, a source address, identifies the transmitter of information, and the destination identifier, for example, a destination address, identifies the recipient of the information. Network 116 may include one or more local area networks (LANs), radio access networks (RANs), metropolitan area networks (MANs), wide area networks (WANs), all or a portion of the global computer network known as the Internet, and/or any other communication system or systems at one or more locations. Boot table 130 is any disk farm or network file system that includes a plurality of boot images 131. While illustrated as remote, boot images 131 may be preloaded by dynamic boot engine 105 to simplify initialization and installation. Boot image 131 is any form, image, pointer, or reference to at least a portion of the boot drive primary operating system partition. Boot image 131 is typically in binary form. Boot image types include kernel images from a file, kernel images from a block device or floppy disk, or the boot sector of some operating system. For example, a Linux boot image might appear as: 0x1B031336, 0x4, 0x90000000, 0x90000200, 0x4, 0x90200, 0x800, 0x800, 0x4, 0x10000, 0x80000, 0x80000, 0x04000004, 0x100000, 0x80000, 0x80000 It will be understood that above example boot image 131 is for illustration purposes only and may include none, some, or all of the illustrated elements as well as additional elements not shown. Moreover, boot image 131 may be in a different layout or format than the above example without departing from the scope of this disclosure. Policies table 132 includes any parameters for managing nodes 108 and applications 114. For example, policies 132 may be for automatically adding or subtracting nodes 108 to application environments. Alternatively or in combination, policies 132 may be used by server 102 to resolve issues between competing applications 114. Generally, policies table 132 may comprise one or more tables stored in a relational database described in terms of SQL statements or scripts. In another embodiment, policies table 132 may store or define various data structures as XML documents, Virtual Storage Access Method (VSAM) files, flat files, Btrieve files, or comma-separated-value (CSV) files. Policies table 132 may also comprise a plurality of tables or files stored on one computer or across a plurality of computers. Moreover, policies table 132 may be local or remote without departing from the scope of this disclosure and store any type of appropriate data. For example, policies table 132 may store individual virtual cluster policies including: i) minimum/maximum number of nodes 108 assigned to an application environment; ii) default number of servers assigned to the application; iii) conditions to dynamically add node 108 to the application environment; iv) conditions to dynamically remove node 108 from the application environment; v) conditions to remove node 108 (such as turning off network access), but leave it up for problem investigation; and vi) conditions under which node 108 should not be removed because application 114 is actively running a transaction or process. In another example, policies table 132 may include any number of inter-virtual cluster policies such as priority, resource sharing, and preemption policies. Priority typically determines which application environment gets the resources if there is a policy conflict. For example, if the priority of a particular application environment is higher, it may get prioritized access to nodes 108. Resource sharing is often based on defined entitlement of the application environments. For example, each application environment may be granted an entitlement to a percentage of nodes 108. Resource sharing may also be based on computer usage over a sliding window of time. Preemption policies may allow high priority application environments to take over nodes 108 from lower priority application environments. Virtual local disk image table 133 is any disk farm or network file system that includes a plurality of virtual local disk images 134. While illustrated as remote, virtual local disk image 134 may be preloaded with the operating system and application software to simplify initialization and installation. Virtual local disk image 134 is any form, image, pointer, or reference to the local disk storage of each virtual node for each application. Virtual local disk image 134 will typically include the operating system, configured services, and installed applications of each application's virtual node. Each virtual local disk image 134 may contain multiple file systems, which may be read-only for sharing between multiple nodes, or modifiable file systems, which are normally specific to an application node. Virtual local disk image 134 may be stored in a hierarchical directory within a traditional file system or may be stored in a recoverable database with a network file system interface provided to the application nodes. In general, application data 140 is any memory, database, storage area network (SAN), or network-attached storage (NAS) for storing data for applications 114. Application data 140 may comprise one or more tables stored in a relational database described in terms of SQL statements or scripts. In another embodiment, application data 140 may store or define various data structures as XML documents, VSAM files, flat files, Btrieve files, or CSV files. Application data 140 may also comprise a plurality of tables or files stored on one computer or across a plurality of computers. Moreover, application data 140 may be local or remote without departing from the scope of this disclosure. Client 120 is any device operable to present the user with an administration screen via a graphical user interface (GUI) 122. At a high level, illustrated client 120 includes at least GUI 122 and comprises an electronic computing device operable to receive, transmit, process and store any appropriate data associated with system 100. It will be understood that there may be any number of clients 120 communicably coupled to server 102. Further, “client 120” and “user of client 120” may be used interchangeably as appropriate without departing from the scope of this disclosure. Moreover, for ease of illustration, each client is described in terms of being used by one user. But this disclosure contemplates that many users may use one computer to communicate commands or view graphical presentations using the same GUI 122. As used in this disclosure, client 120 is intended to encompass a personal computer, touch screen terminal, workstation, network computer, kiosk, wireless data port, cell phone, personal data assistant (PDA), one or more processors within these or other devices, or any other suitable processing device. For example, client 120 may comprise a computer that includes an input device, such as a keypad, touch screen, mouse, or other device that can accept information, and an output device that conveys information associated with the operation of server 102 or clients 120, including digital data, visual information, or GUI 122. Both the input device and output device may include fixed or removable storage media such as a magnetic computer disk, CD-ROM, or other suitable media to both receive input from and provide output to users of clients 120 through the administration and job submission display, namely GUI 122. GUI 122 comprises a graphical user interface operable to allow the system (or network) administrator to interface with system 100 to monitor applications 114 or system performance, modify virtual clusters, or any suitable supervisory purpose. Generally, GUI 122 provides the user of client 120 with an efficient and user-friendly presentation of data provided by system 100. GUI 122 may comprise a plurality of customizable frames or views having interactive fields, pull-down lists, and buttons operated by the user. In one embodiment, GUI 122 presents display that presents the various graphical views of application environments or policy screens and receives commands from the user of client 120 via one of the input devices. These graphical views may include i) graphical representations of the current status of application environments, nodal resources, and monitored loads; ii) graphical representations of application environment and nodal loads and usage over time; iii) wizards; and iv) views of which application 114 is running in each application environment and on each node 108. In short, GUI 122 may present any physical and logical status or characteristics of nodes 108 to the system administrator and receive various commands from the administrator. In one embodiment, GUI 122 may allow an administrator to create, delete, copy, and modify application environments. The administrator may also set up application environment sharing policies, activate and deactivate application environments, monitor states and loads of application environments and nodes 108 using GUI 122. Further, GUI 122 may allow the adding or subtracting of nodes 108 from active application environments. GUI 122 may also present alerts to an administrator based on various system 100 characteristics such as, for example, configurable load levels were reached on node 108 or within an application environment, a node 108 became unavailable, application environment started or stopped, node 108 was added or subtracted from application environment, server 102 was unable to meet minimum application environment requirements, or a level of service requirement (such as transaction response time) was exceeded. It should be understood that the term graphical user interface may be used in the singular or in the plural to describe one or more graphical user interfaces and each of the displays of a particular graphical user interface. Therefore, GUI 122 contemplates any graphical user interface, such as a generic web browser, that processes information in system 100 and efficiently presents the results to the user. GUI 122 also contemplates a secured browser operable to communicate via SSL-HTTPS. Server 102 can accept data from client 120 via the web browser (e.g., Microsoft Internet Explorer or Netscape Navigator) and return the appropriate HTML or XML responses using network 116. In one aspect of operation, dynamic boot engine 105 selects a distributed application 114. Based on one or more associated policies 132, dynamic boot engine 105 may dynamically add or subtract one or more selected nodes 108 to the particular application environment or virtual cluster. Based on the retrieved policies 132, dynamic boot engine 105 selects the appropriate boot image 132 for the selected nodes 108. For example, if there are already four nodes 108 executing a portion of application 114, then dynamic boot engine 105 automatically selects the fifth boot image 132 (at least partially based on node's 108 hardware and other characteristics and the one or more policies 132) that is compatible with application 114. Based on the retrieved policies 132, dynamic boot engine 105 may also select the appropriate virtual local disk image 134 for the selected nodes 108. Once the appropriate boot image 132 and/or virtual local disk image 134 are selected, dynamic boot engine 105 flashes node 108 with a pointer or other reference to the selected boot image 132 and virtual local disk image 134 and reboots node 108. Once node 108 is initialized (normally less than fifteen seconds), dynamic boot engine 105 (or some other job scheduler) executes the appropriate task, process, or other portion of application 104 on the selected node 108. FIG. 2 is a flowchart illustrating an example method 200 for dynamically rebooting a node 108 within one embodiment of the present disclosure. FIG. 2 illustrates method 200, which generally describes a dynamic allocation of one of a plurality of nodes 108 to a virtual cluster or application environment. Of course, any number of nodes 108 may be sequentially or concurrently reset, rebooted, or otherwise allocated within the scope of this disclosure. At a high level, method 200 includes selecting node 108 for allocation to an application's 114 environment, resetting boot image 132 of the selected node 108, and rebooting the node 108. The following description focuses on the operation of dynamic boot engine 105 in performing method 200. But system 100 contemplates using any appropriate combination and arrangement of logical elements implementing some or all of the described functionality. Method 200 begins at step 205, where dynamic boot engine 105 determines that software application 114 would should be allocated more nodes 108. This determination may occur using any appropriate technique. For example, the administrator may manually add node 108 to the application environment for application 114. In another example, dynamic boot engine 105 may dynamically determine that nodes 108 may or should be used based on policies 132. Next, at step 210, dynamic boot engine 105 determines if there are any unutilized computing nodes 108 available. If there are more nodes 108 available, then dynamic boot engine 105 selects first available computing node 108 using any suitable technique at step 215. For example, dynamic boot engine 105 may select node 108 based on physical location, virtual location, application 114 compatibility, processor speed, or any other suitable characteristic. At decisional step 220, dynamic boot engine 105 determines if the selected node is compatible with application 114. If node 108 is not compatible with application 114, then dynamic boot engine 105 brings down the selected node using any suitable technique at step 225. Next, dynamic boot engine 105 dynamically selects policy 132 based on the software application 114 at step 230. For example, dynamic boot engine 105 may determine that three nodes 108 are currently executing software application 114. Based on this determination, dynamic boot engine 105 locates the fourth logical node 108 in policy 132. Based on the selected policy 132, dynamic boot engine 105 flashes the selected node with a pointer to a new boot image 131 at step 235 and associates virtual local disk image 134 at step 237. As described above, dynamic boot engine 105 may flash EEPROM 111 or any other suitable component. Next, dynamic boot engine 105 boots the selected node 108 using the new boot image 131 at step 240. Once the node 108 has been rebooted (or if the node was already compatible with application 114), then dynamic boot engine 105 executes application 114 on the selected node 108 at step 245 and method 200 ends. Returning to decisional step 210, if there were no computing nodes 108 available, then dynamic boot engine 105 selects an optimum utilized node 108 for application 114 at step 250. This selection of optimum node 108 may occur in any appropriate fashion such as, for example, determining the least utilized node 108, selecting a compatible node 108, or determining some other “best fit”. At step 255, dynamic boot engine 105 kills the current processing on selected node 108 at step 255. Dynamic boot engine 105 may terminate the processing using any suitable technique such as executing an application-specific command, killing a process using the operating system, and others. At decisional step 260, dynamic boot engine 105 determines if the selected node 108 is compatible with application 114. If node 108 is not compatible with application 114, then dynamic boot engine 105 brings down the selected node using any suitable technique at step 265. Next, dynamic boot engine 105 dynamically selects policy 132 based on the software application 114 at step 270. For example, dynamic boot engine 105 may determine that three nodes 108 are currently executing software application 114. Based on this determination, dynamic boot engine 105 locates the fourth logical node 108 in policy 132. Based on the selected policy 132, dynamic boot engine 105 flashes the selected node with a pointer to a new boot image 131 at step 275 and associates virtual local disk image 134 at step 277. As described above, resource management engine may flash EEPROM 111 or any other suitable component. Next, dynamic boot engine 105 boots the selected node 108 using the new boot image 131 and virtual local disk image 134 at step 280. Once the node 108 has been rebooted (or if the node was already compatible with application 114), then dynamic boot engine 105 executes application 114 on the selected node 108 at step 285 and method 200 ends. The preceding flowchart and accompanying description illustrate only exemplary method 200. System 100 contemplates using any suitable technique for performing these and other tasks. Accordingly, many of the steps in this flowchart may take place simultaneously and/or in different orders than as shown. Moreover, system 100 may use methods with additional steps, fewer steps, and/or different steps, so long as the methods remain appropriate. Although this disclosure has been described in terms of certain embodiments and generally associated methods, alterations and permutations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of example embodiments does not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of this disclosure. | <SOH> BACKGROUND OF THE INVENTION <EOH>Typically, enterprise applications are executed on dedicated compute resources. Often, an enterprise will include a variety of computing environments for different instances of the application such as production, test, and development. These multiple computing environments are typically the same size and capacity as the live or production instance. Moreover, the non-production environments are frequently idle for extended periods of time. This normally results in large amounts of wasted computing resources and labor expense in maintaining and administering these various environments. Currently, enterprises may use provisioning as an attempt to address these issues. Generally, provisioning is the process of instantiating compute resources to the enterprise application by copying the local disk from a repository to the resource. The resource is then booted with the provisioned operating system and software through a process that normally takes over ten minutes. | <SOH> SUMMARY OF THE INVENTION <EOH>This disclosure provides a system and method for computer cluster virtualization that includes selecting a distributed application. A policy associated with the distributed application is retrieved. One of a plurality of nodes is dynamically selected, possibly based on the policy. Then, a boot image of the selected node is reset based, at least in part, on the retrieved policy, with the boot image being compatible with the distributed application. Then, a virtual disk image is associated with the node. At least a portion of the distributed application is then executed on the reset node using the associated virtual disk image. The invention has several important technical advantages. For example, one possible advantage of the present invention is that it allows for computing nodes to be reprovisioned on-the-fly to become a member of a virtual cluster for a distributed application, thereby possibly reducing provisioning times to fifteen seconds or less. Another possible advantage of the present disclosure may be a reduction in Information Technology (IT) hardware and maintenance costs by at least thirty percent. Moreover, when an application is not at a peak processing period, idles nodes of that application may be dynamically reallocated or reprovisioned to other distributed applications. Yet another possible advantage is that it provides centralized capacity planning, performance monitoring, and simplified administration. Further, the present invention may allow for better node failure management. Various embodiments of the invention may have none, some, or all of these advantages. Other technical advantages of the present invention will be readily apparent to one skilled in the art. | 20040415 | 20120529 | 20051020 | 63607.0 | 3 | DAFTUAR, SAKET K | SYSTEM AND METHOD FOR COMPUTER CLUSTER VIRTUALIZATION USING DYNAMIC BOOT IMAGES AND VIRTUAL DISK | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,825,401 | ACCEPTED | Received signal quality determination | A method of generating a received signal quality signal in a communication system, the method comprising: receiving a signal from a physical channel, extracting a transport channel format combination indicator from the received signal, processing one or more transport channel signals, contained in the received signal, in accordance with the extracted transport channel format combination indicator, said processing including at least channel decoding, and generating a received signal quality signal in dependence on the quality of the or each transport channel signal prior to channel decoding. | 1. A method of generating a received signal quality signal in a communication system, the method comprising: receiving a signal from a physical channel; extracting a transport channel format combination indicator from the received signal; processing one or more transport channel signals, contained in the received signal, in accordance with the extracted transport channel format combination indicator; said processing including at least channel decoding; and generating a received signal quality signal in dependence on the quality of the or each transport channel signal prior to channel decoding. 2. A method according to claim 1, wherein the or each transport channel signal comprises a sequence of data blocks. 3. A method according to claim 2, wherein the quality of the or each transport channel signal is represented by a block bit error rate determined prior to channel decoding. 4. A method according to claim 3, wherein the determined bit error rate of a transport channel signal is averaged over period comprising a plurality of data blocks. 5. A method according to claim 4, wherein, in the case of a plurality of transport channel signals, the bit error rates of each transport channel signal are averaged over the same period. 6. A method according to claim 5, including calculating an average bit error rate across the transport channel signals, wherein the average is weighted in dependence on the transport formats used for said transport signals. 7. A method according to claim 1, including the step of transmitting the received signal quality signal in a control channel. 8. A communication device comprising: a receiver for receiving a signal from a physical channel; processing means configured for: extracting a transport channel format combination indicator from the received signal; processing one or more transport channel signals, contained in the received signal, in accordance with the extracted transport channel format combination indicator; said processing including at least channel decoding; and generating a received signal quality signal in dependence on the quality of the or each transport channel signal prior to channel decoding. 9. A device according to claim 7, wherein the processing means is configured for processing transport channel signals comprising sequences of data blocks. 10. A device according to claim 9, wherein the quality of the or each transport channel signal is represented by a block bit error rate determined prior to channel decoding. 11. A device according to claim 10, wherein the processing means is configures such that the determined bit error rate of a transport channel signal is averaged over period comprising a plurality of data blocks. 12. A device according to claim 11, wherein the processing means is configured such that, in the case of there being a plurality of transport channel signals, the bit error rates of each transport channel signal are averaged over the same period. 13. A device according to claim 12, wherein the processing means is configured for calculating an average bit error rate across the transport channel signals, such that the average is weighted in dependence on the transport formats used for said transport signals. 14. A device according to claim 8, including a transmitter, wherein the processing means is configured for causing the transmitter to transmit the received signal quality signal in a control channel of a communication network. 15. A method of generating a received signal quality signal in a communication system, the method comprising: receiving a signal from a physical channel, the signal comprising one or more transport channels; extracting a transport channel format combination indicator from the received signal and determining the bit error rate therefore; and generating a received signal quality signal in dependence on the bit error rate of the extracted transport channel format combination indicator. 16. A method according to claim 15, wherein the determined bit error rates of a plurality of transport channel format combination indicator instances are averaged. 17. A method according to claim 15, including the step of transmitting the received signal quality signal in a control channel. 18. A communication device comprising: a receiver for receiving a signal from a physical channel, the signal comprising one or more transport channels; and processing means configured for: extracting a transport channel format combination indicator from a received signal and determining the bit error rate therefore; and generating a received signal quality signal in dependence on the bit error rate of the extracted transport channel format combination indicator. 19. A device according to claim 18, wherein the processing means is configured for averaging the determined bit error rates of a plurality of transport channel format combination indicator instances. 20. A device according to claim 18, including a transmitter, wherein the processing means is configured for causing the transmitter to transmit the received signal quality signal in a control channel of a communication network. 21. A method of generating a received signal quality signal in a communication system, the method comprising: receiving a signal from a physical channel, the signal comprising a plurality of bursts each including a training sequence; and generating a received signal quality signal in dependence on the bit error rate of the training sequence of a received burst. 22. A method according to claim 21, wherein the determined bit error rates of the training sequences of a plurality of bursts are averaged. 23. A method according to claim 21, wherein the bit error rate of a training sequence is produced by comparing a received training sequence with a reference training sequence. 24. A method according to claim 21, including the step of transmitting the received signal quality signal in a control channel. 25. A communication device comprising: a receiver for receiving a signal from a physical channel, the signal comprising a plurality of bursts each including a training sequence; and processing means configured for generating a received signal quality signal in dependence on the bit error rate of the training sequence of a received burst. 26. A device according to claim 25, wherein the processing means is configured for averaging the determined bit error rates of the training sequences of a plurality of bursts. 27. A device according to claim 25, wherein the processing means is configured such that the bit error rate of a training sequence is produced by comparing a received training sequence with a reference training sequence. 28. A device according to claim 25, including a transmitter, wherein the processing means is configured for causing the transmitter to transmit the received signal quality signal in a control channel of a communication network. | FIELD OF THE INVENTION The present invention relates to the determination of received signal quality in a radio communication system. BACKGROUND TO THE INVENTION In a radio communication network, such as a mobile phone network, mobile stations monitor the quality of received signals and report the received signal quality back to a base station, typically in a control channel. It has been proposed that a mobile station report received signal quality in a slow associated control channel (SACCH) using a three bit code. The signal quality is determined as the bit error rate (BER) of the received signal before channel decoding and is averaged over one SACCH multiframe, for example 480 ms. The BER is only used if the a block is correctly received, i.e. it passes a CRC (cyclic redundancy code) check. If a block is not correctly received, a default notional BER of, for example 50%, is assumed. SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided a method of generating a received signal quality signal in a communication system, the method comprising: receiving a signal from a physical channel; extracting a transport channel format combination indicator from the received signal; processing one or more transport channel signals, contained in the received signal, in accordance with the extracted transport channel format combination indicator; said processing including at least channel decoding; and generating a received signal quality signal in dependence on the quality of the or each transport channel signal prior to channel decoding. According to the first aspect of the present invention, there is also provided a communication device comprising: a receiver for receiving a signal from a physical channel; processing means configured for: extracting a transport channel format combination indicator from the received signal; processing one or more transport channel signals, contained in the received signal, in accordance with the extracted transport channel format combination indicator; said processing including at least channel decoding; and generating a received signal quality signal in dependence on the quality of the or each transport channel signal prior to channel decoding. The or each transport channel signal may comprise a sequence of data blocks. The quality of the or each transport channel signal may be represented by a block bit error rate determined prior to channel decoding. The determined bit error rate of a transport channel signal may be averaged over period comprising a plurality of data blocks. In the case of there being a plurality of transport channel signals, the bit error rates of each transport channel signal may be averaged over the same period. An average bit error rate may be calculated across the transport channel signals with the averaging being weighted in dependence on the transport formats used for said transport signals. The received signal quality signal may be transmitted in a control channel. According to a second aspect of the present invention, there is provided a method of generating a received signal quality signal in a communication system, the method comprising: receiving a signal from a physical channel, the signal comprising one or more transport channels; extracting a transport channel format combination indicator from the received signal and determining the bit error rate therefore; and generating a received signal quality signal in dependence on the bit error rate of the extracted transport channel format combination indicator. According to the second aspect of the present invention, there is also provided a communication device comprising: a receiver for receiving a signal from a physical channel, the signal comprising one or more transport channels; and processing means configured for: extracting a transport channel format combination indicator from a received signal and determining the bit error rate therefore; and generating a received signal quality signal in dependence on the bit error rate of the extracted transport channel format combination indicator. The determined bit error rates of a plurality of transport channel format combination indicator instances may be averaged. The received signal quality signal may be transmitted in a control channel. According to a third aspect of the present invention, there is provided a method of generating a received signal quality signal in a communication system, the method comprising: receiving a signal from a physical channel, the signal comprising a plurality of bursts each including a training sequence; and generating a received signal quality signal in dependence on the bit error rate of the training sequence of a received burst. According to the third aspect of the present invention, there is also provided a communication device comprising: a receiver for receiving a signal from a physical channel, the signal comprising a plurality of bursts each including a training sequence; and processing means configured for generating a received signal quality signal in dependence on the bit error rate of the training sequence of a received burst. The determined bit error rates of the training sequences of a plurality of bursts may be averaged. The bit error rate of a training sequence may be produced by comparing a received training sequence with a reference training sequence. The received signal quality signal may be transmitted in a control channel. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a mobile communication system according to the present invention; FIG. 2 is a block diagram of a mobile station; FIG. 3 is a block diagram of a base transceiver station; FIG. 4 illustrates the frame structure; FIG. 5 illustrates a packet data channel; FIG. 6 illustrates the sharing of a radio channel between two half-rate packet channels; FIG. 7 illustrates the lower levels of a protocol stack; FIG. 8 is a block diagram illustrating the processing of the transport channels of a received physical layer signal; FIG. 9 is a block diagram illustrating received signal quality determination; FIG. 10 is a flowchart of a first part of a received signal quality determination process; FIG. 11 is a flowchart of a second part of a received signal quality determination process; FIG. 12 is a block diagram illustrating another approach to signal quality determination; FIG. 13 is a flowchart illustrating another received signal quality determination process; FIG. 14 is a block diagram illustrating yet another approach to signal quality determination; and FIG. 15 is a flowchart illustrating yet another received signal quality determination process. DETAILED DESCRIPTION OF EMBODIMENTS Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings. Referring to FIG. 1, a mobile phone network 1 comprises a plurality of switching centres including first and second switching centres 2a, 2b. The first switching centre 2a is connected to a plurality of base station controllers including first and second base station controllers 3a, 3b. The second switching centre 2b is similarly connected to a plurality of base station controllers (not shown). The first base station controller 3a is connected to and controls a base transceiver station 4 and a plurality of other base transceiver stations. The second base station controller 3b is similarly connected to and controls a plurality of base transceiver stations (not shown). In the present example, each base transceiver station services a respective cell. Thus, the base transceiver station 4 services a cell 5. However, a plurality of cells may be serviced by one base transceiver station by means of directional antennas. A plurality of mobile stations 6a, 6b are located in the cell 5. It will be appreciated what the number and identities of mobile stations in any given cell will vary with time. The mobile phone network 1 is connected to a public switched telephone network 7 by a gateway switching centre 8. A packet service aspect of the network includes a plurality of packet service support nodes (one shown) 9 which are connected to respective pluralities of base station controllers 3a, 3b. At least one packet service support gateway node 10 connects the or each packet service support node 10 to the Internet 11. The switching centres 3a, 3b and the packet service support nodes 9 have access to a home location register 12. Communication between the mobile stations 6a, 6b and the base transceiver station 4 employs a time-division multiple access (TD MA) scheme. Referring to FIG. 2, the first mobile station 6a comprises an antenna 101, an rf subsystem 102, a baseband DSP (digital signal processing) subsystem 103, an analogue audio subsystem 104, a loudspeaker 105, a microphone 106, a controller 107, a liquid crystal display 108, a keypad 109, memory 110, a battery 111 and a power supply circuit 112. The rf subsystem 102 contains if and rf circuits of the mobile telephone's transmitter and receiver and a frequency synthesizer for tuning the mobile station's transmitter and receiver. The antenna 101 is coupled to the rf subsystem 102 for the reception and transmission of radio waves. The baseband DSP subsystem 103 is coupled to the rf subsystem 102 to receive baseband signals therefrom and for sending baseband modulation signals thereto. The baseband DSP subsystems 103 includes codec functions which are well-known in the art. The analogue audio subsystem 104 is coupled to the baseband DSP subsystem 103 and receives demodulated audio therefrom. The analogue audio subsystem 104 amplifies the demodulated audio and applies it to the loudspeaker 105. Acoustic signals, detected by the microphone 106, are pre-amplified by the analogue audio subsystem 104 and sent to the baseband DSP subsystem 4 for coding. The controller 107 controls the operation of the mobile telephone. It is coupled to the rf subsystem 102 for supplying tuning instructions to the frequency synthesizer and to the baseband DSP subsystem 103 for supplying control data and management data for transmission. The controller 107 operates according to a program stored in the memory 110. The memory 110 is shown separately from the controller 107. However, it may be integrated with the controller 107. The display device 108 is connected to the controller 107 for receiving control data and the keypad 109 is connected to the controller 107 for supplying user input data signals thereto. The battery 111 is connected to the power supply circuit 112 which provides regulated power at the various voltages used by the components of the mobile telephone. The controller 107 is programmed to control the mobile station for speech and data communication and with application programs, e.g. a WAP browser, which make use of the mobile station's data communication capabilities. The second mobile station 6b is similarly configured. Referring to FIG. 3, greatly simplified, the base transceiver station 4 comprises an antenna 201, an rf subsystem 202, a baseband DSP (digital signal processing) subsystem 203, a base station controller interface 204 and a controller 207. The rf subsystem 202 contains the if and rf circuits of the base transceiver station's transmitter and receiver and a frequency synthesizer for tuning the base transceiver station's transmitter and receiver. The antenna 201 is coupled to the rf subsystem 202 for the reception and transmission of radio waves. The baseband DSP subsystem 203 is coupled to the rf subsystem 202 to receive baseband signals therefrom and for sending baseband modulation signals thereto. The baseband DSP subsystems 203 includes codec functions which are well-known in the art. The base station controller interface 204 interfaces the base transceiver station 4 to its controlling base station controller 3a. The controller 207 controls the operation of the base transceiver station 4. It is coupled to the rf subsystem 202 for supplying tuning instructions to the frequency synthesizer and to the baseband DSP subsystem for supplying control data and management data for transmission. The controller 207 operates according to a program stored in the memory 210. Referring to FIG. 4, each TDMA frame, used for communication between the mobile stations 6a, 6b and the base transceiver stations 4, comprises eight 0.577 ms time slots. A “26 multiframe” comprises 26 frames and a “51 multiframe” comprises 51 frames. Fifty one “26 multiframes” or twenty six “51 multiframes” make up one superframe. Finally, a hyperframe comprises 2048 superframes. The data format within the time slots varies according to the function of a time slot. A normal burst, i.e. time slot, comprises three tail bits, followed by 58 encrypted data bits, a 26-bit training sequence, another sequence of 58 encrypted data bits and a further three tail bits. A guard period of eight and a quarter bit durations is provided at the end of the burst. A frequency correction burst has the same tail bits and guard period. However, its payload comprises a fixed 142 bit sequence. A synchronization burst is similar to the normal burst except that the encrypted data is reduced to two clocks of 39 bits and the training sequence is replaced by a 64-bit synchronization sequence. Finally, an access burst comprises eight initial tail bits, followed by a 41-bit synchronization sequence, 36 bits of encrypted data and three more tail bits. In this case, the guard period is 68.25 bits long. When used for circuit-switched speech traffic, the channelisation scheme is as employed in GSM. Referring to FIG. 5, full rate packet switched channels make use of 12 4-slot radio packets spread over a “51 multiframe”. Idle slots follow the third, sixth, ninth and twelfth radio packet. Referring to FIG. 6, for half rate, packet switched channels, both dedicated and shared, slots are allocated alternately to two sub-channels. The baseband DSP subsystems 103, 203 and controllers 107, 207 of the mobile stations 6a, 6b and the base transceiver stations 4 are configured to implement two protocol stacks. The first protocol stack is for circuit switched traffic and is substantially the same as employed in conventional GSM systems. The second protocol stack is for packet switched traffic. Referring to FIG. 7, the layers relevant to the radio link between a mobile station 6a, 6b and a base station controller 4 are the radio link control layer 401, the medium access control layer 402 and the physical layer 403. The radio link control layer 401 has two modes: transparent and non-transparent. In transparent mode, data is merely passed up or down through the radio link control layer without modification. In non-transparent mode, the radio link control layer 401 provides link adaptation and constructs data blocks from data units received from higher levels by segmenting or concatenating the data units as necessary and performs the reciprocal process for data being passed up the stack. It is also responsible for detecting lost data blocks or reordering data block for upward transfer of their contents, depending on whether acknowledged mode is being used. This layer may also provide backward error correction in acknowledged mode. The medium access control layer 402 is responsible for allocating data blocks from the radio link control layer 401 to appropriate transport channels and passing received radio packets from transport channels to the radio link control layer 403. The physical layer 403 is responsible to creating transmitted radio signals from the data passing through the transport channels and passing received data up through the correct transport channel to the medium access control layer 402. Referring to FIG. 8, data produced for applications 404a, 404b, 404c propagates up the protocol stack from the medium access control layer 402. The data from the applications 404a, 404b, 404c can belong to any of a plurality of classes for which different qualities of service are required. Data belonging to a plurality of classes may be required by a single application. The medium access control layer 402 directs data to the applications 404a, 404b, 404c from different transport channels 405, 406, 407 according to class to which it belongs. Each receive transport channel 405, 406, 407 can be configured to process received signals according to a plurality of processing schemes 405a, 405b, 405c, 406a, 406b, 406c, 407a, 407b, 407c. The configuration of the transport channels 405, 406, 407 is established during call setup on the basis of the capabilities of the mobile station 6a, 6b and the network and the nature of the application or applications 404a, 404b, 404c being run. The processing schemes 405a, 405b, 405c, 406a, 406b, 406c, 407a, 407b, 407c are unique combinations of cyclic redundancy check 405a, 406a, 407a, channel decoding 405b, 406b, 407b and rate matching 405c, 406c, 407c. These unique processing schemes are the reciprocals of transmitter processing schemes which define different “transport formats”. An interleaving scheme may be selected for each transport channel 405, 406, 407 and require corresponding de-interleaving 405d, 406d, 407d. Thus, different transport channels may use different interleaving schemes and, in alternative embodiments, different interleaving schemes may be used at different times by the same transport channel. The combined data rate produced for the transport channels 405, 406, 407 must not exceed that of physical channel or channels allocated to the mobile station 6a, 6b. This places a limit on the transport format combinations that can be permitted. For instance, if there are three transport formats TF1, TF2, TF3 for each transport channel, the following combinations might be valid:— TF1 TF1 TF2 TF1 TF3 TF3 but not TF1 TF2 TF2 TF1 TF1 TF3 The received signal is de-interleaved 411 and then demultiplexed by a demultiplexing process 410, which outputs transport channel signals to respective transport channel de-interleaving processes 405d, 406d, 407d. A transport format combination indicator is spread across one radio packet with portions placed in fixed positions in each burst, on either side of the training symbols (FIG. 9) in this example. The complete transport format combination indicator therefore occurs at fixed intervals, i.e. the block length 20 ms. This makes it possible to ensure transport format combination indicator detection when different interleaving types are used e.g. 8 burst diagonal and 4 burst rectangular interleaving. Since the transport format combination indicator is not subject to variable interleaving, it can be readily located by the receiving station and used to control processing of the received data. The transport format combination indicator is extracted from the received data stream by a transport format combination indicator extraction process 414 after the deinterleaving process 411. The transport format combination indicator from the transport format combination indicator extraction process 414 is decoded by a decoding process 413. The decoded transport format combination indicator is then processed by a transport format combination detecting process 412 which provides information on the current transport format combination to the medium access control layer 402. This information is then used in the medium access control layer 402 to select the appropriate decoding and de-interleaving process for the transport formats used in the received signal. FIG. 9 illustrates received signal quality determination in the case where the received physical layer signal carries a data stream comprising three transport channels using respective formats. Of course, the data stream may comprise more or fewer transport channels and the same transport format may be used by more than one of the transport channels. Referring to FIG. 9, first, second and third transport channel quality determiners 501, 502, 503 receive the cyclic redundancy check results from respective cyclic redundancy check processes 405a, 406a, 407a and a bit error rate estimate from respective channel decoding processes 405b, 406b, 407b. The operation of the first transport channel quality determiner 501 will now be described with reference to FIG. 10. Referring to FIG. 10, at the start of a SACCH multiframe period (also known as the SACCH reporting period), the CRC result for a first transport block is received from the first cyclic redundancy check process 405a (step s1). If the result is determined to be true, i.e. the CRC is correct, (step s2), the BER for the first transport block is obtained from the first channel decoder 405b (step s3) and stored (step s4). A block counter is then incremented (step s5). It is then determined whether the current SACCH multiframe period has come to an end (step s6). If the current SACCH multiframe period has not come to an end (step s6), the program flow returns to step s1 where the CRC for the next block is obtained. If, at step s2, it is determined that the cyclic redundancy check result is determined to be false, steps s3 to s5 are skipped. When all of the blocks of the current the current SACCH multiframe period have been processed (step s6), the BER is averaged over a period corresponding to the product of the block period and the number of correctly received transport blocks, i.e. the value accumulated by the step s5. The second and third transport channel quality determiners 502, 503 operate in the same way as the first transport channel quality determiners 501 except that the cyclic redundancy check result and the BER estimates are obtained from the corresponding cyclic redundancy check process 406a, 407a and channel decoders 406b, 407b. The transport channel quality determiners 501, 502, 503 output their average BERs and transport block counts to a physical channel quality determiner 504. The operation of the physical channel quality determiner 504 will now be described with reference to FIG. 11. Referring to FIG. 11, the physical channel quality determiner 504 obtains the TFCI applicable to the most recent transport channel quality determinations (step s11) and then receives the transport block counts from the transport channel quality determiners 501, 502, 503 (step s12). The TFCI information determines what percentage of each radio packet is used by each transport channel. This information is used to convert the transport block counts into the percentage of the data in the transmitted data stream that was correctly received in one SACCH multiframe, according to: P = ∑ c = 1 n b ( c ) · p ( c ) b T ( c ) where c is the transport channel number, n is the number of transport channels, b is the number of correctly received bits in the transport block, b is the number of bits in the transport block in the transmitted signal and p is the percentage of the data stream used by a particular transport channel. If the result P is greater than or equal to 50%, the BERs are obtained from the transport channel quality determiners 501, 502, 503 (step s15). The BERs are then averaged (step s16). In the present embodiment, the BERs are averaged in accordance with the following: B = ∑ c = 1 n b ( c ) · p ( c ) ∑ c = 1 n p ( c ) where B is the average BER. If, however, the percentage of the data in the transmitted data stream that was incorrectly received is greater than 50% (step s14), the average bit error rate B is set arbitrarily to 50%. The average bit error rate B is then quantized and encoded into 3 bits which are made available for transmission to a base transceiver station 4 by the mobile station 6a in the SACCH as a received signal quality report. It will be appreciated that the formulae given above are examples of the effect required and that the value ranges and scaling factors actual used may vary. A second embodiment of the present invention will now be described. A mobile station is as described above with the exception of the generation of the received signal quality report. In this embodiment, the report is based on the quality of the TFCI signal. Referring to FIG. 12, TFCI BERs are fed from the TFCI decoder 413 (FIG. 8) to a received signal quality determiner 601. The received signal quality determiner 601 generates a received signal quality signal in dependence on the TFCI BERs from the TFCI decoder 413 and outputs it for transmission in the SACCH. Referring to FIG. 13, the received signal quality determiner 601 obtains a first TFCI BER for the first TFCI transmitted in a SACCH multiframe period (step s31) and stores it (step s32). Successive TFCI BERs are then obtained (step s31) and stored (step s32) until the BER for the last TCFI of the current SACCH multiframe period ends (step s33). When the last BER has been obtained and stored, the stored BERs are averaged (step s34) and then the average quantized and encoded (step s35) and output (step s36) for transmission to a base transceiver station 4 by the mobile station 6a in the SACCH as a received signal quality report. A third embodiment of the present invention will now be described. A mobile station is as described above with the exception of the generation of the received signal quality report. In this embodiment, the report is based on the quality of the received training sequences. As shown in FIG. 4, each burst comprises a training sequence sandwiched between two blocks of data bits. The training sequences are predetermined. Referring to Referring to FIG. 14, received training sequences are fed to a received signal quality determiner 701. The received signal quality determiner 701 generates a received signal quality signal in dependence on the received training sequences and outputs it for transmission in the SACCH. Referring to FIG. 12, TFCI BERs are fed from the TFCI decoder 413 (FIG. 8) to a received signal quality determiner 601. The received signal quality determiner 601 generates a received signal quality signal in dependence on the TFCI BERs from the TFCI decoder 413 and outputs it for transmission in the SACCH. Referring to FIG. 15, the received signal quality determiner 701 obtains a first training sequence in a SACCH multiframe period (step s41) and compares it with a reference copy (step s42). The number of differences between the received training sequence and the reference is added to a record of the errors for the current SACCH multiframe period (step 43). The errors in successive training sequences are then obtained (step s42) and added to the error record (step s43) until the training sequence of the last burst in the current SACCH multiframe period has been processed (step s44). When the last training sequence has been processed, the accumulated error count is quantized (step s45) and output (step s46) for transmission to a base transceiver station 4 by the mobile station 6a in the SACCH as a received signal quality report. The three embodiments described above may be combined to produce additional embodiments. For instance, bit error rates obtained by two or three techniques may be averaged to produce a bit error rate that is then quantized, encoded and transmitted to a base transceiver station 4 by the mobile station 6a in the SACCH as a received signal quality report. It is to be understood that the foregoing embodiments are merely examples and that many modifications are possible without departing from the spirit and scope of the appended claims. | <SOH> BACKGROUND TO THE INVENTION <EOH>In a radio communication network, such as a mobile phone network, mobile stations monitor the quality of received signals and report the received signal quality back to a base station, typically in a control channel. It has been proposed that a mobile station report received signal quality in a slow associated control channel (SACCH) using a three bit code. The signal quality is determined as the bit error rate (BER) of the received signal before channel decoding and is averaged over one SACCH multiframe, for example 480 ms. The BER is only used if the a block is correctly received, i.e. it passes a CRC (cyclic redundancy code) check. If a block is not correctly received, a default notional BER of, for example 50%, is assumed. | <SOH> SUMMARY OF THE INVENTION <EOH>According to a first aspect of the present invention, there is provided a method of generating a received signal quality signal in a communication system, the method comprising: receiving a signal from a physical channel; extracting a transport channel format combination indicator from the received signal; processing one or more transport channel signals, contained in the received signal, in accordance with the extracted transport channel format combination indicator; said processing including at least channel decoding; and generating a received signal quality signal in dependence on the quality of the or each transport channel signal prior to channel decoding. According to the first aspect of the present invention, there is also provided a communication device comprising: a receiver for receiving a signal from a physical channel; processing means configured for: extracting a transport channel format combination indicator from the received signal; processing one or more transport channel signals, contained in the received signal, in accordance with the extracted transport channel format combination indicator; said processing including at least channel decoding; and generating a received signal quality signal in dependence on the quality of the or each transport channel signal prior to channel decoding. The or each transport channel signal may comprise a sequence of data blocks. The quality of the or each transport channel signal may be represented by a block bit error rate determined prior to channel decoding. The determined bit error rate of a transport channel signal may be averaged over period comprising a plurality of data blocks. In the case of there being a plurality of transport channel signals, the bit error rates of each transport channel signal may be averaged over the same period. An average bit error rate may be calculated across the transport channel signals with the averaging being weighted in dependence on the transport formats used for said transport signals. The received signal quality signal may be transmitted in a control channel. According to a second aspect of the present invention, there is provided a method of generating a received signal quality signal in a communication system, the method comprising: receiving a signal from a physical channel, the signal comprising one or more transport channels; extracting a transport channel format combination indicator from the received signal and determining the bit error rate therefore; and generating a received signal quality signal in dependence on the bit error rate of the extracted transport channel format combination indicator. According to the second aspect of the present invention, there is also provided a communication device comprising: a receiver for receiving a signal from a physical channel, the signal comprising one or more transport channels; and processing means configured for: extracting a transport channel format combination indicator from a received signal and determining the bit error rate therefore; and generating a received signal quality signal in dependence on the bit error rate of the extracted transport channel format combination indicator. The determined bit error rates of a plurality of transport channel format combination indicator instances may be averaged. The received signal quality signal may be transmitted in a control channel. According to a third aspect of the present invention, there is provided a method of generating a received signal quality signal in a communication system, the method comprising: receiving a signal from a physical channel, the signal comprising a plurality of bursts each including a training sequence; and generating a received signal quality signal in dependence on the bit error rate of the training sequence of a received burst. According to the third aspect of the present invention, there is also provided a communication device comprising: a receiver for receiving a signal from a physical channel, the signal comprising a plurality of bursts each including a training sequence; and processing means configured for generating a received signal quality signal in dependence on the bit error rate of the training sequence of a received burst. The determined bit error rates of the training sequences of a plurality of bursts may be averaged. The bit error rate of a training sequence may be produced by comparing a received training sequence with a reference training sequence. The received signal quality signal may be transmitted in a control channel. | 20040415 | 20081014 | 20051020 | 96852.0 | 0 | JACKSON, BLANE J | RECEIVED SIGNAL QUALITY DETERMINATION | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,825,639 | ACCEPTED | Heated pet mat | A heated pet mat has a fire retardant covering in the shape of a truncated circle folded in half to form two layers. A resistive heating element is sandwiched between the two layers. | 1. A heated pet mat, comprising: a fire retardant covering having a shape of a truncated circle folded in half to form two layers; and a resistive heating element sandwiched between the two layers. 2. The heated pet mat of claim 1, wherein the two layers are sealed along an edge. 3. The heated pet mat of claim 2, wherein the fire retardant covering is made of acrylonitrile butadien styrene plastic. 4. The heated pet mat of claim 2, wherein the fire retardant covering is made of polyvinyl chloride. 5. The heated pet mat of claim 2, wherein the two layers are sealed by welding the two layers together. 6. The heated pat mat of claim 1, wherein the truncated circle has a width that is 10% shorter than a radius. 7. A heated pat mat, comprising: a housing having a shape of a truncated semicircle; and a heating element contained within the housing. 8. The heated pet mat of claim 7 wherein the housing is formed of two layers of fire retardant plastic. 9. The heated pet mat of claim 8, wherein the two layers of plastic are made of acrylonitrile butadien styrene plastic. 10. The heated pet mat of claim 7, wherein the heating element includes a resistive heat wire. 11. The heated pet mat of claim 10, wherein the heating element includes a transfer foil. 12. A heated pet mat, comprising: a first layer of fire retardant plastic in a shape of a truncated semicircle; a first transfer foil having approximately a same shape as the first layer of fire retardant plastic adjacent to the first layer of fire retardant plastic; a layer of heating wire adjacent to the first transfer foil; a second transfer foil having approximately the same shape as the first layer of fire retardant plastic adjacent to the layer of heating wire; and a second layer of fire retardant plastic having approximately the same shape as the first layer of fire retardant plastic and sealed along an edge to the first layer of fire retardant plastic and second layer of fire retardant plastic. | RELATED APPLICATIONS The present invention claims priority on provisional patent application Ser. No. 60/463,705, filed on April, 17 2003, entitled “Heated Dog Mat”. FIELD OF THE INVENTION The present invention relates generally to the field of pet products and more particularly to a heated pet mat. BACKGROUND OF THE INVENTION In recent years round or igloo shaped doghouses have become the most commonly sold doghouses. Unfortunately, the heated pet mats for rectangular doghouses do not fit in these round doghouses. As a result, there has been a need for a heated pet mat that fits in the new round dog houses. Attempts to make round or semicircular heated pet mats have not worked, because of the costs of the waste associated with this shape. A rectangular pad is capable of having almost no waste when the plastic cover is cut from a sheet of plastic. Unfortunately there is significant waste when cutting a circle or pair of semicircles from a sheet of plastic. In fact the unusable plastic sheet is over 20% of the total plastic area. This has resulted in pricing round or semicircular heated pet mats out of the market. Thus there exists a need for a heated pet mat that can be made economically. SUMMARY OF INVENTION A heated pet mat that overcomes these and other problems has a fire retardant covering in the shape of a truncated circle folded in half to form two layers. A resistive heating element is sandwiched between the two layers. The two layers are sealed along an edge. The fire retardant covering may be made of acrylonitrile butadien styrene plastic. The fire retardant covering may be made of polyvinyl chloride. The two layers may be sealed by welding the two layers together. The truncated circle may ave a width that is 10% shorter than a radius. In one embodiment, a heated pat mat has a housing in the shape of a truncated semicircle. A heating element is contained within the housing. In one embodiment, the housing is formed of two layers of fire retardant plastic. The two layers of plastic may be made of acrylonitrile butadien styrene plastic. The heating element may include a resistive heat wire. The heating element may include a transfer foil. In one embodiment, a heated pet mat has a first layer of fire retardant plastic in the shape of a truncated semicircle. A first transfer foil has approximately a same shape as the first layer of fire retardant plastic and is adjacent to the first layer of fire retardant plastic. A layer of heating wire is adjacent to the first transfer foil. A second transfer foil has approximately the same shape as the first layer of fire retardant plastic and is adjacent to the layer of heating wire. A second layer of fire retardant plastic has approximately the same shape as the first layer of fire retardant plastic and is sealed along an edge to the first layer of fire retardant plastic and second layer of fire retardant plastic. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cartoon drawing of a round doghouse capable of using the invention; FIG. 2 is a top view of a heated pet mat in accordance with one embodiment of the invention; FIG. 3 is an exploded side view of heated pet mat in accordance with one embodiment of the invention; and FIG. 4 is an example of a sheet of plastic used in forming the outer layers of a heated pet mat in accordance with one embodiment of the invention. DETAILED DESCRIPTION OF THE DRAWINGS The heated pet mat described herein allows heated pet mats to be made economically for round pet enclosures. FIG. 1 is a cartoon drawing of a round doghouse 10 capable of using the invention. A dog 12 is shown next to the round doghouse 10. In the winter the dog 12 requires some form of heat source in the doghouse 10 to avoid exposure and to be comfortable. FIG. 2 is a top view of a heated pet mat 20 in accordance with one embodiment of the invention. The heated pet mat 20 has covering 22 that is in the form of a truncated semicircle. The truncated semicircle is a semicircle 24 having a radius 26. The ends 28 and 30 of the semicircle shown in dashed lines have been removed from the semicircle 24. Note that it would be possible to use a semicircle on top of a rectangle, but this would increase the amount of wasted covering material. This shape fits easily in the round doghouse 10 and in fact is easier to place in a round doghouse than a true semicircular or circular mat. The dog is unlikely to be laying on the cutout areas 28 & 30 and therefore the lost coverage has little or no effect on its intended use. Note that the top 32 of the mat commonly is placed at the back (opposite the door) of the doghouse 10. The mat 34 includes an electrical cord for heating the mat 20. Non-electrical heating elements could be used, but an electrical heating element is presently considered the most effective method of heating the mat 20. In one embodiment, the covering 22 is made of a fire retardant material. Note that in one embodiment, the width (w) 36 is 10% shorter or less than the radius 26. FIG. 3 is an exploded side view of heated pet mat 40 in accordance with one embodiment of the invention. The mat 40 has a first layer of fire retardant plastic 42. The next layer is a first transfer foil 44. A layer of heating wire 46 is next to the first transfer foil 44. The transfer foil 44 distributes the heat from the heating wire 46 and radiates the heat out through the cover 42. A second heating foil 48 is placed on the other side of the heating element 46. A second layer of fire retardant plastic 50 is placed against the second heating foil 48. The edges 52 of the two layers of plastic are sealed together to form a sandwich. In one embodiment, the edges 52 are welded together by RF welding or ultrasonic welding. In one embodiment, the foils 44 & 48 and the heating element 46 have the same approximate shape as the layers 42 & 50. In one embodiment, the plastic layers are made of acrylonitrile butadien styrene (ABS) plastic or polyvinyl chloride (PVC) plastic. FIG. 4 is an example of a sheet of plastic 60 used in forming the outer layers of a heated pet mat in accordance with one embodiment of the invention. The sheet of plastic 60 is cut to form either two truncated semicircles 62, 64 or as a truncated circle 66. The truncated circle 66 can be folded to form the two layers of the outer cover of the heated pet mat. The shaded parts 68 of the sheet of plastic 60 are the wasted material. This design significantly reduces the amount of wasted material 68 compared to a full circular design on to full semicircles. This allows the heated pet mat to be produced economically. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alterations, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alterations, modifications, and variations in the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>In recent years round or igloo shaped doghouses have become the most commonly sold doghouses. Unfortunately, the heated pet mats for rectangular doghouses do not fit in these round doghouses. As a result, there has been a need for a heated pet mat that fits in the new round dog houses. Attempts to make round or semicircular heated pet mats have not worked, because of the costs of the waste associated with this shape. A rectangular pad is capable of having almost no waste when the plastic cover is cut from a sheet of plastic. Unfortunately there is significant waste when cutting a circle or pair of semicircles from a sheet of plastic. In fact the unusable plastic sheet is over 20% of the total plastic area. This has resulted in pricing round or semicircular heated pet mats out of the market. Thus there exists a need for a heated pet mat that can be made economically. | <SOH> SUMMARY OF INVENTION <EOH>A heated pet mat that overcomes these and other problems has a fire retardant covering in the shape of a truncated circle folded in half to form two layers. A resistive heating element is sandwiched between the two layers. The two layers are sealed along an edge. The fire retardant covering may be made of acrylonitrile butadien styrene plastic. The fire retardant covering may be made of polyvinyl chloride. The two layers may be sealed by welding the two layers together. The truncated circle may ave a width that is 10% shorter than a radius. In one embodiment, a heated pat mat has a housing in the shape of a truncated semicircle. A heating element is contained within the housing. In one embodiment, the housing is formed of two layers of fire retardant plastic. The two layers of plastic may be made of acrylonitrile butadien styrene plastic. The heating element may include a resistive heat wire. The heating element may include a transfer foil. In one embodiment, a heated pet mat has a first layer of fire retardant plastic in the shape of a truncated semicircle. A first transfer foil has approximately a same shape as the first layer of fire retardant plastic and is adjacent to the first layer of fire retardant plastic. A layer of heating wire is adjacent to the first transfer foil. A second transfer foil has approximately the same shape as the first layer of fire retardant plastic and is adjacent to the layer of heating wire. A second layer of fire retardant plastic has approximately the same shape as the first layer of fire retardant plastic and is sealed along an edge to the first layer of fire retardant plastic and second layer of fire retardant plastic. | 20040415 | 20100713 | 20050127 | 64956.0 | 0 | ROBINSON, DANIEL LEON | HEATED PET MAT | SMALL | 0 | ACCEPTED | 2,004 |
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10,825,692 | ACCEPTED | Hookworm vaccine | Preparations which elicit an immune response to hookworm antigens and which may be utilized as hookworm vaccines are provided. In addition, a method of increasing the effectiveness of vaccinations against infectious diseases in patients infected with hookworm is provided. The method involves chemically treating the hookworm infestation prior to administering the vaccine. | 1-33. (cancelled): 34. A method for enabling vaccination of a patient against infectious diseases, comprising the steps of: a) treating hookworm infection to a degree sufficient to increase lymphocyte proliferation; and b) vaccinating said patient against said infectious disease. 35. The method of claim 34 wherein said infectious disease is selected from the group consisting of HIV, tuberculosis, malaria, measles, tetanus, diphtheria, pertussis, and polio. 36. A method for enabling hookworm vaccination, comprising the steps of: a) chemically treating a hookworm infected patient to ameliorate hookworm infection; and b) vaccinating said patient with a recombinant or synthetic antigen or fragment thereof derived from hookworm after amelioration of hookworm infection. 37-97. (Cancelled) 98. A composition comprising: a cocktail of recombinant or synthetic antigens derived from hookworm, and, a pharmacologically acceptable carrier. 99. The composition of claim 98, wherein said composition comprises at least one larval stage antigen and at least one adult stage antigen. 100. The composition of claim 98, wherein said antigen is ASP-1, ASP-2, MTP-1, 103 (SAA), 16, GST or an antigen having at least 80% homology therewith. 101. The composition of claim 98, wherein said antigen is selected from the group consisting of GST, CP-2, APR-1, APR-2, MEP-1, TMP or an antigen having at least 80% homology therewith. 102. The composition of claim 98, wherein a species of said hookworm is selected from the group consisting of Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, and Ancyclostoma duodenale. 103. A method of vaccinating or eliciting an immune response to hookworm in a mammal, comprising the step of, administering to said mammal an effective amount of a composition comprising a recombinant or synthetic antigen derived from hookworm, and a pharmacologically acceptable carrier. 104. The method of claim 103 wherein said composition includes a cocktail of recombinant or synthetic antigens derived from hookworm, and, a pharmacologically acceptable carrier. 105. The method of claim 103, wherein said composition comprises at least one larval stage antigen and at least one adult stage antigen. 106. The method of claim 103, wherein said antigen is ASP-1, ASP-2, MTP-1, 103 (SAA), 16, GST, or an antigen having at least 80% homology therewith. 107. The method of claim 103, wherein said antigen is selected from the group consisting of GST, CP-2, APR-1, APR-2, MEP-1, TMP, or an antigen having at least 80% homology therewith. 108. The method of claim 103, wherein a species of said hookworm is selected from the group consisting of Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, and Ancyclostoma duodenale. 109. The method of claim 103, further comprising the step of chemically treating a hookworm-infected patient prior to said step of administering. 110. A method of reducing blood loss in a patient infected with hookworm, comprising the step of administering to said patient an effective amount of a composition comprising a recombinant or synthetic antigen derived from hookworm, and a pharmacologically acceptable carrier. 111. The method of claim 110 wherein said composition includes a cocktail of recombinant or synthetic antigens derived from hookworm, and, a pharmacologically acceptable carrier. 112. The method of claim 110, wherein said composition comprises at least one larval stage antigen and at least one adult stage antigen. 113. The method of claim 110, wherein said antigen is ASP-1, ASP-2, MTP-1, 103 (SAA), 16, GST, or an antigen having at least 80% homology therewith. 114. The method of claim 110, wherein said antigen is selected from the group consisting of GST, CP-2, APR-1, APR-2, MEP-1, TMP, or an antigen having at least 80% homology therewith. 115. The method of claim 110, wherein a species of said hookworm is selected from the group consisting of Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, and Ancyclostoma duodenale. 116. The method of claim 110, further comprising the step of chemically treating a hookworm-infected patient prior to said step of administering. 117. A method of reducing hookworm size, or quantitative egg count or hookworm burden in a patient infected with hookworm, comprising the step of administering to said mammal an effective amount of a composition comprising a recombinant or synthetic antigen derived from hookworm, and a pharmacologically acceptable carrier. 18. The method of claim 117 wherein said composition includes a cocktail of recombinant or synthetic antigens derived from hookworm, and, a pharmacologically acceptable carrier. 19. The method of claim 117, wherein said composition comprises at least one larval stage antigen and at least one adult stage antigen. 120. The method of claim 117, wherein said antigen is ASP-1, ASP-2, MTP-1, 103, 16, GST, or an antigen having at least 80% homology therewith. 121. The method of claim 117, wherein said antigen is selected from the group consisting of GST, CP-2, APR-1, APR-2, MEP-1, TMP, or an antigen having at least 80% homology therewith. 122. The method of claim 117, wherein a species of said hookworm is selected from the group consisting of Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, and Ancyclostoma duodenale. 123. The method of claim 117, further comprising the step of chemically treating a hookworm-infected patient prior to said step of administering. 124. A method of decreasing L3 migration across skin of a mammal, comprising the step of administering to said mammal an effective amount of a composition comprising a recombinant or synthetic antigen derived from hookworm, and a pharmacologically acceptable carrier. 125. The method of claim 124 wherein said composition includes a cocktail of recombinant or synthetic antigens derived from hookworm, and, a pharmacologically acceptable carrier. 126. The method of claim 124, wherein said composition comprises at least one larval stage antigen and at least one adult stage antigen. 127. The method of claim 124, wherein said antigen is ASP-1, ASP-2, MTP-1, 103 (SAA), 16, GST, or an antigen having at least 80% homology therewith. 128. The method of claim 124, wherein said antigen is selected from the group consisting of GST, CP-2, APR-1, APR-2, MEP-1, TMP, or an antigen having at least 80% homology therewith. 129. The method of claim 124, wherein a species of said hookworm is selected from the group consisting of Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, and Ancyclostoma duodenale. 130. The method of claim 124, further comprising the step of chemically treating a hookworm-infected patient prior to said step of administering. 131. A nucleotide sequence represented by SEQ ID NO: 76. 132. An amino acid sequence represented by SEQ ID NO: 77. | This application claims priority to International patent application PCT/US02/33106 (filed 17 October, 2002, of which it is a continuation-in-part), and to U.S. provisional patent application 60/329,553 (filed 17 October, 2001), 60/332, 007 (filed 23 Nov. 2001) 60,375,404 (filed 26 Apr. 2001), and 60/505,848 (filed 26 Sep. 2003). The entire contents of each application to which priority is claimed is hereby incorporated by reference. This invention was made in part by funds from government grants: Tropical Medicine Research Center (TMRC) grant from the National Institutes of Health P50 A1-39461 and A1-32726. The United States government may have rights in this invention. BACKGROUND OF THE INVENTION 1. Field of the Invention The invention generally relates to a vaccine for hookworm. In particular, the invention provides vaccines based on parasite-derived antigens. BACKGROUND OF THE INVENTION Hookworm infection is a significant public health concern in developing countries around the world, causing enteritis, intestinal blood loss, anemia, developmental delays, and malnutrition. It is estimated that there are more than one billion cases of human hookworm infection worldwide, with 194 million cases in China alone (Hotez et al. 1997). In some regions of China such as Hainan Province in the South China Sea more than 60 percent of the population harbors hookworms (Gandhi et al. 2001). Most of the pathology caused by hookworm results from the adult stages of the parasite in the human intestine. The attachment of adult Ancylostoma and Necator hookworms to the mucosa and submucosa of the vertebrate small intestine is one of the best-defined examples of host-parasite relationships in all of parasitology. Comprised of several cubic millimeters of host mucosal and submucosal tissue lodged in the buccal capsule of the parasite, it is possible to actually touch the host-parasite relationship at necropsy or autopsy (Kalkofen, 1970; Kalkofen, 1974). The dog hookworm Ancylostoma caninum is a major cause of morbidity and mortality in dogs throughout the world including subtropical regions of North America. Hookworm-associated blood loss leading to severe anemia and even death can occur in dogs between 2 and 3 weeks after a single primary infection (Soulsby, 1982; Jones and Hotez, 2002). Significantly, A. caninum has also been recently identified as an important human pathogen. Zoonotic infection with one adult A. caninum parasite can result in eosinophilic enteritis syndrome, an inflammatory condition of the intestine in response to invasion by the parasite (Prociv and Croese, 1990). The pathogenesis of A. caninum infection is associated with the intestinal blood loss that occurs during adult worm attachment and feeding in the mammalian small intestine (Kalkofen, 1970; Kalkofen, 1974). Current efforts for the treatment and control of hookworm infestations are limited to periodic removal of adult hookworms from patients with anthelmintics. This approach has several limitations, including rapid reinfection following treatment, requiring multiple visits, and the eventual development of anthelmintic resistant strains of hookworms following several years of heavy anthelmintic treatments (Savioli et al. 1997; Geerts and Gryseels, 2000). Thus, it would be of great benefit to have available additional methods for both treating and preventing hookworm infection in mammals. For example, it would be highly advantageous to have available vaccines to treat or prevent hookworm infection. SUMMARY OF THE INVENTION The present invention provides preparations for eliciting an immune response against hookworm. The preparations contain various hookworm antigens which have been identified as useful for eliciting an immune response. These preparations may be used as vaccines against hookworm in mammals, for example, in humans. As a result of the administration of the preparations, the vaccinated mammal may develop an immune response against hookworm which causes immunity to infection by the parasite, or may display a lower worm burden, decreased blood loss, or a decrease in size of parasitizing hookworms. To that end, the invention provides a composition comprising a recombinant or synthetic antigen or a fragment thereof derived from hookworm, and a pharmacologically acceptable carrier. The recombinant or synthetic antigen may display at least about 80% identity to an antigen such as ASP-1, ACE, CTL, APR-1, APR-2, TMP, MEP-1, MEP-2, ASP-1, ASP-2, ASP-3, ASP-4, ASP-5, ASP-6, TTR-1, TTR-2, 103 (also referred to as SAA-1), 16, VWF, CTL, API, MTP-1, MTP-2, MTP-3, FAR-1, KPI-1, APR-1, APR-2, AP, ASP-1, ASP-2, API, CP-1, CP-2, CP-3, CP-4, CYS, and GST. In preferred embodiments, the antigen is ASP-1, ASP-2, MTP-1, 103 (SAA), 16, GST, TMP, MEP-1, APR or CP-2. The antigens may be derived from a hookworm from species such as Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, and Ancylostoma duodenale. The invention also provides a method of eliciting an immune response to hookworm in a mammal. The method includes the step of administering to the mammal an effective amount of a composition comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm, and a pharmacologically acceptable carrier. The recombinant or synthetic antigen may display at least about 80% identity to an antigen such as ASP-1, ACE, CTL, APR-1, APR-2, TMP, MEP-1, MEP-2, ASP-1, ASP-2, ASP-3, ASP-4, ASP-5, ASP-6, TTR-1, TTR-2, 103 (also referred to as SAA-1), 16, VWF, CTL, API, MTP-1, MTP-2, MTP-3, FAR-1, KPI-1, APR-1, APR-2, AP, ASP-1, ASP-2, API, CP-1, CP-2, CP-3, CP-4, CYS, and GST. In preferred embodiments, the antigen is ASP-1, ASP-2, MTP-1,103 (SAA), 16, GST, TMP, MEP-1, APR, or CP-2. The antigens may be derived from a hookworm from species such as Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, and Ancylostoma duodenale. The invention further provides a method of vaccinating a mammal against hookworm. The method includes the step of administering to the mammal an effective amount of a composition comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm and a pharmacologically acceptable carrier. The recombinant or synthetic antigen may display at least about 80% identity with an antigen such as ASP-1, ACE, CTL, APR-1, APR-2, TMP, MEP-1, MEP-2, MTP-1, ASP-1, ASP-2, ASP-3, ASP-4, ASP-5, ASP-6, TTR-1, TTR-2, 103 (also referred to as SAA-1), 16, VWF, CTL, API, MTP-1, MTP-2, MTP-3, FAR-1, KPI-1, APR-1, APR-2, AP, ASP-1, ASP-2, MTP-1, API, CP-1, CP-2, CP-3, CP-4, CYS, and GST. In preferred embodiments, the antigen is ASP-1, ASP-2, MTP-1, 103 (SAA), 16, GST, TMP, MEP-1, APR, or CP-2. The antigens may be derived from a hookworm from species such as Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, and Ancylostoma duodenale. The invention further provides a composition comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm. The recombinant or synthetic antigen display at least about 80% identity with an antigen such as ASP-1, ACE, CTL, APR-1, APR-2, TMP, MEP-1, MEP-2, ASP-1, ASP-2, ASP-3, ASP-4, ASP-5, ASP-6, TTR-i, TTR-2, 103 (also referred to as SAA-1), 16, VWF, CTL, API, MTP-1, MTP-2, MTP-3, FAR-1, KPI-1, APR-1, APR-2, AP, ASP-1, ASP-2, API, CP-1, CP-2, CP-3, CP-4, CYS, and GST. The composition further comprises a pharmacologically acceptable carrier. In preferred embodiments, the antigen is ASP-1, ASP-2, MTP-1, 103 (SAA), 16, GST, TMP, MEP-1, APR, or CP-2. The antigens may be derived from a hookworm from species such as Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, and Ancylostoma duodenale. The invention further provides a vaccine comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm. The recombinant or synthetic antigen displays at least about 80% identity with an antigen such as ASP-1, ACE, CTL, APR-1, APR-2, TMP, MEP-1, MEP-2, ASP-1, ASP-2, ASP-3, ASP-4, ASP-5, ASP-6, TTR-1, TTR-2, 103 (also referred to as SAA-1), 16, VWF, CTL, API, MTP-1, MTP-2, MTP-3, FAR-1, KPI-1, APR-1, APR-2, AP, ASP-1, ASP-2, API, CP-1, CP-2, CP-3, CP-4, CYS, and GST. The vaccine further comprises a pharmacologically acceptable carrier. In preferred embodiments, the antigen is ASP-1, ASP-2, MTP-1, 103 (SAA), 16, GST, TMP, MEP-1, APR, or CP-2. The antigens may be derived from a hookworm from species such as Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, and Ancylostoma duodenale. The present invention further provides a composition for eliciting an immune response comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm. The recombinant or synthetic antigen displays at least about 80% identity with an antigen selected from the group consisting of ASP-1, ACE, CTL, APR-1, APR-2, TMP, MEP-1, MEP-2, ASP-1, ASP-2, ASP-3, ASP-4, ASP-5, ASP-6, TTR-1, TTR-2, 103 (also referred to as SAA-1), 16, VWF, CTL, API, MTP-1, MTP-2, MTP-3, FAR-1, KPI-1, APR-1, APR-2, AP, ASP-1, ASP-2, API, CP-1, CP-2, CP-3, CP-4, CYS, and GST. The composition further comprises a pharmacologically acceptable carrier. In preferred embodiments, the antigen is ASP-1, ASP-2, MTP-1, 103 (SAA), 16, GST, TMP, MEP-1, APR, or CP-2. The antigens may be derived from a hookworm from species such as Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, and Ancylostoma duodenale. The invention further provides a method for enabling vaccination of a patient against parasite derived infectious diseases. The method includes the steps of treating hookworm infection to a degree sufficient to increase lymphocyte proliferation, and vaccinating the patient against an infectious disease such as HIV, tuberculosis, malaria, measles, tetanus, diphtheria, pertussis, or polio. The present invention also provides a method for enabling hookworm vaccination. The method includes the steps of chemically treating a hookworm infected patient to ameliorate hookworm infection, and vaccinating the patient with a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm after amelioration of hookworm infection. In the method, the hookworm infection may be completely eradicated by treatment, or may be lessened to such an extent that hookworm vaccination is effective. The recombinant or synthetic antigen may display at least about 80% identity with an antigen such as ASP-1, ACE, CTL, APR-1, APR-2, TMP, MEP-1, MEP-2, ASP-1, ASP-2, ASP-3, ASP-4, ASP-5, ASP-6, TTR-1, TTR-2, 103 (also referred to as SAA-1), 16, VWF, CTL, API, MTP-1, MTP-2, MTP-3, FAR-1, KPI-1, APR-1, APR-2, AP, ASP-1, ASP-2, API, CP-1, CP-2, CP-3, CP-4, CYS, and GSTThe antigens may be derived from a hookworm from species such as Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, and Ancylostoma duodenale. The present invention also provides a method for reducing blood loss in a patient infected with hookworm. The method includes the step of administering to the patient a composition comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm, and a pharmacologically acceptable carrier. The present invention also provides a method for reducing hookworm size in a patient infected with hookworm. The method includes the step of administering to the patient a composition comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm, and a pharmacologically acceptable carrier. The invention further provides a method of reducing hookworm burden in a patient infected with hookworm. The method comprises the step of administering to the patient a composition comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm, and a pharmacologically acceptable carrier. The present invention also provides the following nucleic acid and amino acid sequences: SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 47, SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 51, SEQ ID NO: 52, SEQ ID NO: 55, SEQ ID NO: 56, SEQ ID NO: 57, SEQ ID NO: 58, SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 62, SEQ ID NO: 63 and SEQ ID NO: 64. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and B. Na-ASP-1: A, cDNA (SEQ ID NO: 1) and B, deduced amino acid sequence (SEQ ID NO: 2). GeneBank accession # AF079521. FIGS. 2A and B. Na-ACE: A, cDNA (SEQ ID NO: 3) and B, deduced amino acid sequence (SEQ ID NO: 4). GeneBank accession # AF536813. FIGS. 3A and B. Na-CTL: A, cDNA (SEQ ID NO: 5) and B, deduced amino acid sequence (SEQ ID NO: 6). FIGS. 4A and B. Na-APR-1: A, cDNA (SEQ ID NO: 7) and B, deduced amino acid sequence (SEQ ID NO: 8). FIGS. 5A and B. Na-APR-2: A, cDNA (SEQ ID NO: 9) and B, deduced amino acid sequence (SEQ ID NO: 10). FIGS. 6A and B. Ac-TMP: A, cDNA (SEQ ID NO: 11) and B, deduced amino acid sequence (SEQ ID NO: 12). FIGS. 7A and B. Ac-MEP-1: A, cDNA (SEQ ID NO: 13) and B, deduced amino acid sequence (SEQ ID NO:14). GeneBank accession # AF273084. FIGS. 8A and B. Ac-MTP-1: A, cDNA (SEQ ID NO: 15) and B, deduced amino acid sequence (SEQ ID NO: 16). GeneBank accession # AY036056. FIGS. 9A and B. Ac-ASP-i: A, cDNA (SEQ ID NO: 17) and B, deduced amino acid sequence (SEQ ID NO: 18). GeneBank accession # AF 132291. FIGS. 10A and B. Ac-ASP-2: A, cDNA (SEQ ID NO: 19) and B, deduced amino acid sequence (SEQ ID NO: 20). GeneBank accession # AF089728. FIGS. 11A and B. Ac-ASP-3: A, cDNA (SEQ ID NO: 21) and B, deduced amino acid sequence (SEQ ID NO: 22). FIGS. 12A and B. Ac-ASP-4: A, cDNA (SEQ ID NO: 23) and B, deduced amino acid sequence (SEQ ID NO: 24). FIGS. 13A and B. Ac-ASP-5: A, cDNA (SEQ ID NO: 25) and B, deduced amino acid sequence (SEQ ID NO: 26). FIGS. 14A and B. Ac-ASP-6: A, cDNA (SEQ ID NO: 27) and B, deduced amino acid sequence (SEQ ID NO: 28). FIGS. 15A and B. Ac-TTR-1: A, cDNA (SEQ ID NO: 29) and B, amino acid sequence (SEQ ID NO:30) deduced from nucleotides 25-531. FIGS. 16A and B. Ac-103: A, cDNA (SEQ ID NO: 31) and B, amino acid sequence (SEQ ID NO: 32). FIGS. 17A and B. Ac-VWF: A, cDNA (SEQ ID NO: 33) and B, amino acid sequence (SEQ ID NO: 34). FIGS. 18A and B. Ac-CTL: A, cDNA (SEQ ID NO: 35) and B, amino acid sequence (SEQ ID NO: 36). FIGS. 19A and B. Ac-API-1: A, cDNA (SEQ ID NO: 37) and B, amino acid sequence (SEQ ID NO: 38) deduced from nucleotides 23-706. FIGS. 20A and B. Ac-MTP-1: A, cDNA (SEQ ID NO: 39) and B, amino acid sequence (SEQ ID NO: 40). FIGS. 21A and B. Ac-MTP-2: A, cDNA (SEQ ID NO: 41) and B, amino acid sequence (SEQ ID NO: 42). FIGS. 22A and B. Ac-MTP-3: A, cDNA (SEQ ID NO: 43) and B, amino acid sequence (SEQ ID NO: 44). FIGS. 23A and B. Ac-FAR-I: A, cDNA (SEQ ID NO: 45) and B, amino acid sequence (SEQ ID NO: 46). GeneBank Acession # AF529181 FIG. 24A-C. Ac-KPI-1: A and B, cDNA (SEQ ID NO: 47) and C, amino acid sequence (SEQ ID NO: 48) deduced from nucleotides 12-2291. FIGS. 25A and B. Ac-APR-i: A, cDNA (SEQ ID NO: 49) and B, amino acid sequence (SEQ ID NO: 50). FIGS. 26A and B. Ac-APR-2: A, partial cDNA sequence (SEQ ID NO: 51) and B, partial amino acid sequence (SEQ ID NO: 52). FIGS. 27A and B. Ac-AP: A, cDNA (SEQ ID NO: 53) and B, amino acid sequence (SEQ ID NO: 54). FIGS. 28A and B. Ay-ASP-1: A, cDNA (SEQ ID NO: 55) and B, amino acid sequence (SEQ ID NO: 56). FIGS. 29A and B. Ay-ASP-2: A, cDNA (SEQ ID NO: 57) and B, amino acid sequence (SEQ ID NO: 58). FIGS. 30A and B. Ay-MTP-1: A, cDNA (SEQ ID NO: 59) and B, amino acid sequence (SEQ ID NO: 60). FIGS. 31A and B. Ay-API-1: A, cDNA (SEQ ID NO: 61) and B, amino acid sequence (SEQ ID NO: 62) deduced from nucleotides 23-703. FIGS. 32A and B. Ay-TTR: A, partial cDNA (SEQ ID NO: 63) and B, partial amino acid sequence (SEQ ID NO: 64). FIGS. 33A and B. Spearman rank order correlations between hookworm burden and anti-MTP-1 antibody titer. A) total worms; B) median EPG. FIG. 34A-C. Antigen-specific geometric mean IgG1 antibody titers in dogs vaccinated with A. caninum recombinant fusion proteins as a function of time. Geometric means were calculated for a total of 6 dogs in each group, except for Ac-AP in which only a single dog developed an antigen-specific antibody response. The arrows denote timed vaccinations. (A) Anti-Ac-APR-1 responses (n=6). (B) Anti-Ac-TMP responses (n=6). (C) Anti-Ac-AP responses (n=1). FIG. 35. Female and male adult A. caninum hookworms recovered from the colons of either vaccinated or alum-injected dogs. FIGS. 36A and B. Spearman rank order correlations between hookworm burden and anti-MTP-1 antibody titer FIGS. 37A and B. A) Relationship between anti-TTR IgE antibodies and hookworm burden reductions; B) Relationship between anti-TTR IgG1 antibodies and hookworm burden reductions FIGS. 38A and B. HV-4 Canine hemoglobin (B) and hematocrit (A) changes following L3 challenge FIG. 39. Statistically significant reduction in worm size (between 1 and 2 mm) among the TTR vaccinated group relative to the adjuvant control group. FIG. 40. CD4+lymphocytes from hookworm-infected (egg positive) individual post-stimulation with Ancylostoma L3 antigen. FIG. 41. CD4+lymphocytes from hookworm-infected (egg positive) individual post-stimulation with Pichia-expresses recombinant Na-ASP-1. FIG. 42. Alignment of deduced amino acid sequences of Ancylostoma-secreted protein (ASP)-1 derived from different species of third-stage hookworm larvae. Sequences were aligned by use of CLUSTAL W software and were prepared for display by use of BOXSHADE software. Black boxes, identical amino acids; gray boxes, similar amino acids; asterisks, amino acids common to every sequence; and arrows, cysteines conserved in all ASPs. Names and GenBank accession nos. are as follows: Ay (A. ceylanicum)-ASP-1 (SEQ ID NO: 56), AAN11402; Ac (A. caninum)-ASP-1 (SEQ ID NO: 18), AAC47001; Ad (A. duodenale)-ASP-1, AAD13339 (SEQ ID NO: 67); and Na (Necator americanus)-ASP-1 (SEQ ID NO: 2), AAD13340. The amino acid sequence identities between Ay-ASP-1 and other hookworm ASP-1 proteins are shown at the end of sequence. FIGS. 43A and B. A, Alignment of deduced amino acid sequences of Ancylostoma-secreted protein (ASP-2 derived from different species of third-stage hookworm larvae. Sequences were aligned by use of CLUSTAL W software and were prepared for display by use of BOXSHADE software. Black boxes, dentical amino acids; gray boxes, similar amino acids; asterisks, amino acids common to every sequence; and arrows, cysteines conserved in all ASPs. The names and GenBank accession nos. are as follows: Ay (A. ceylanicum)-ASP-2 (SEQ ID NO: 58), AAP41953; Ac (A. caninum)-ASP-2 (SEQ ID NO: 20), AAC35986; Ad (A. duodenale)ASP-2 (SEQ ID NO: 68), AAP41951; and Na (Necator americanus)-ASP-2 (SEQ ID NO: 69), AAP41952. The amino acid sequence identities between Ay-ASP-2 (SEQ ID NO: 58) and other hookworm ASP-2 proteins are shown at the end of sequence. B, cDNA sequence of Na-ASP-2 (SEQ ID NO: 82). FIG. 44. Total IgG titers (geometric) in serum from golden Syrian hamsters vaccinated with Ay (Ancylostoma ceylanicum)-ASP-1 (SEQ ID NO: 56) mean SD (Ancylostoma-secreted protein) and Ay-ASP-2 (SEQ ID NO: 58) formulated with either Quil A or Montanide ISA-720 as adjuvant. Serum samples were obtained 8 days after the final vaccination (see Materials and Methods). Vaccinations with radiation-attenuated A. ceylanicum third-stage infective larvae (irL3) are included as a positive control (hamsters/group). Antibody titers were determined by measuring the last dilution that resulted in 3 SD above n p 10 background. FIG. 45. The relationship between age and prevalence (bars) and log transformed eggs per gram of feces (Inepg) (●) in people infected with Necator americanus in Minas Gerais, Brazil (n=495) and Hainan Province, China (n=396). Lines represent standard error of the mean for Inepg. FIG. 46. Secretion, purification and biochemical analysis of recombinant Ac-ASP-2 (SEQ ID NO: 20) expressed in Sf9 insect cells. The purified protein displayed a mass of 24,492 da (major species) by mass spectroscopy with smaller quantities of minor species observed between 24,592 and 25,537 da FIG. 47. The distribution of anti-ASP-2 serum antibody isotypes from people in hookworm-endemic areas of Hainan Province, China (n=222) and Minas Gerais, Brazil (n=285) Antibody isotypes not shown here were not detected against ASP-2. Restriction in the antibody subclass response to ASP-2. FIG. 48. The relationship between antibody isotype responses to ASP-2 and intensity of infections with Necator americanus. The relationship between individuals with IgE (IgE-pos) or without IgE (IgE-neg) against ASP-2 and fecal egg counts in samples from Hainan Province, China (a) and Minas Gerais, Brazil (b). Bars indicate 95% confidence intervals for the mean fecal egg counts. P values and percentages indicate differences in mean fecal egg counts between IgE-positive and IgE-negative groups. FIG. 49. Canine anti-ASP-2 antibodies induced by vaccination recognize recombinant and parasite-derived ASP-2. Geometric mean titers of the IgG1 (□), IgG2 (●) and IgE (▴) antibody responses against ASP-2 in canines vaccinated with recombinant ASP-2 The control group was vaccinated with AS03 adjuvant only and had no titers (data not shown). The letter C inside a gray arrow refers to larval challenge; the letter N inside a gray arrow refers to necropsy. Individual dogs (A-E) vaccinated with recombinant ASP-2 generated antibodies at day 75 (before larval challenge) that immunoprecipitated native ASP-2 from L3 extracts. FIG. 50. Vaccination of dogs with recombinant ASP-2 provides protection against hookworm infection. Fecal egg counts for canines vaccinated with ASP-2 or the adjuvant AS03 alone (con) (a). Comparison of adult worms retrieved during necropsy from the colon and small intestine of canines vaccinated with ASP-2/AS03 and AS03 alone (con) (b). Bars indicate standard error of the mean for each group. Sera from dogs immunized with ASP-2 partially inhibited migration of A. caninum third stage larvae through canine skin in vitro (c). There was a 30% reduction (P=0.02) in the numbers of L3 that penetrated canine skin when L3 were first incubated in sera from vaccinated dogs compared to control animals. Values for inhibition assays are raw data. FIG. 51. pH profile of the catalytic activity of recombinant Ac-CP-2 against the substrate Z-Phe-Arg-AMC. FIG. 52. The geometric mean titers of the IgG1(A) and IgG2 (B) antibody responses of vaccinated dogs against recombinant Ac-CP-2 formulated with AS03 (▪), AS02 (●), ISA70 (□), alum (▴) or alum alone without CP-2 (◯). Open arrows on the X-axis indicate the days of vaccination (numbers inside) and larval challenge (C). FIG. 53. The geometric mean egg counts from dogs immunized with Ac-CP-2 formulated with different adjuvants or alum alone (control). The error bars refer to standard error of the mean. The numbers within the bars refer to the P-value of a Dunnett (Post Hoc) test, a pairwise multiple comparison t test that compares a set of treatments against a single control mean. FIG. 54. The proportions of male to female worms recovered from dogs immunized with Ac-CP-2 formulated with different adjuvants or alum adjuvant alone. Individual proportions are shown for each dog and the mean value for each group is denoted by a bar. Where the proportions were significantly different (P<0.1 using a Wilcoxon-Signed Ranks test) between vaccine and control groups, P values are denoted beneath the mean. FIG. 55. Mean and medians of the worm burdens in vaccinated dogs relative to control (AS03) dogs. 1=Ac-ASP-2; 2=Ac-API; 3=Ac-MEP; 4=Ac-APR-1; 5=AS03 (adjuvant). FIG. 56. Reduction in QECs (Quantitative Egg Counts) following vaccination and challenge. FIG. 57A-C. A, cDNA sequence of A. caninum GST (SEQ ID NO: 76) and B, corresponding amino acid sequence (SEQ ID NO: 77). C, alignment of coding region and amino acid sequence. Amino acids 1-19 are signal peptide. FIGS. 58A and B. Graphic representation of adult worms recovered from the vaccinated and control dogs. FIG. 59. Median adult hookworm counts after use of trimmed mean calculation. FIG. 60. A, Median and B, mean reduction in quantitative egg counts. FIGS. 61A and B. Na-CP-2: A, cDNA (SEQ ID NO: 83) and B, amino acid sequence (SEQ ID NO: 84). FIGS. 62A and B. Na-CP-3: A, cDNA (SEQ ID NO: 85) and B, amino acid sequence (SEQ ID NO: 86). FIGS. 63A and B. Na-CP-4: A, cDNA (SEQ ID NO: 87) and B, amino acid sequence (SEQ ID NO: 88). FIGS. 64A and B. Na-CP-5: A, cDNA (SEQ ID NO: 89) and B, amino acid sequence (SEQ ID NO: 90). FIGS. 65A and B. Na-MEP-1: A, cDNA (SEQ ID NO: 91) and B, amino acid sequence (SEQ ID NO: 92). FIGS. 66A and B. Ac-16: A, cDNA (SEQ ID NO: 93) and B, amino acid sequence (SEQ ID NO: 94). FIGS. 67A and B. Ay-16: A, cDNA (SEQ ID NO: 95) and B, amino acid sequence (SEQ ID NO: 96). FIGS. 68A and B. Ac-CP-1: A, cDNA (SEQ ID NO: 97) and B, amino acid sequence (SEQ ID NO: 98). FIGS. 69A and B. Ac-Cys: A, cDNA (SEQ ID NO: 99) and B, amino acid sequence (SEQ ID NO: 100). FIGS. 70A and B. Ac-MEP-2: A, cDNA (SEQ ID NO: 101) and B, amino acid sequence (SEQ ID NO: 102). FIGS. 71A and B. Ac-TTR-2: A, cDNA (SEQ ID NO: 103) and B, amino acid sequence (SEQ ID NO: 104). FIGS. 72A and B. Ay-APR-1: A, cDNA (SEQ ID NO: 105) and B, amino acid sequence (SEQ ID NO: 106). FIGS. 73A and B. Ay-CYS: A, cDNA (SEQ ID NO: 107) and B, amino acid sequence (SEQ ID NO: 108). FIGS. 74A and B. Na-16: A, cDNA (SEQ ID NO: 109) and B, amino acid sequence (SEQ ID NO: 110). FIGS. 75A and B. Na-MTP-1: A, cDNA (SEQ ID NO: 111) and B, amino acid sequence (SEQ ID NO: 112). FIGS. 76A and B. Na-103 (SAA-1): A, cDNA (SEQ ID NO: 113) and B, amino acid sequence (SEQ ID NO: 114). FIGS. 77A and B. A, Geometric mean of antibody titers; B, reduction in worm burdens. FIGS. 78A and B. A, EPG per group, the average of two cages per group of 10 hamsters. B, Percentage of change of Hb at necropsy relative to pre-challenge values. FIGS. 79A and B. A, spleen weights of hamsters by group; B, percentage body weight change at necropsy relative to pre-challenge. FIGS. 80A and B. geometric mean of IgG titers. Relationship between antibody titers and A, worm burden and B, QECs. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION The present invention provides compositions for use in eliciting an immune response to hookworm in a mammal. Such compositions may be utilized as vaccines for use in the treatment and/or prevention of hookworm infection. The vaccines comprise purified preparations of antigens which are derived from hookworm, and a pharmacologically acceptable carrier. By “derived from” we mean that the antigen is a biomolecule that originated from (i.e. was isolated from) a hookworm. For example, the antigen may be a protein, a polypeptide, or an antigenic fragment of a protein, or polypeptide, which constitutes part of a hookworm organism. Typically, such an antigen is isolated and at least partially purified from a hookworm by methods which are well known to those of skill in the art (for example, see Examples section below). When manufactured for use in eliciting an immune response or as a vaccine, such antigens may be “synthetic” i.e. obtained synthetically (e.g. by peptide synthesis in the case of polypeptides and protein fragments), or “recombinant” i.e. obtained by genetic engineering techniques (e.g. by production in a host cell which harbors a vector containing DNA which encodes the antigen). Those of skill in the art will recognize that many such suitable expression systems are available, including but not limited to those which employ E. coli, yeast (e.g. Pichia pastoris), baculovirus/insect cells, plant cells, and mammalian cells, and. In preferred embodiments of the invention, the antigens are expressed in a yeast or baculovirus/insect cell expression system. Examples of specific antigens, their amino acid primary sequences, and nucleic acid sequences which encode them are given herein. For ease of reference, Table I lists some exemplary antigens and their corresponding SEQ ID NOS. However, those of skill in the art will recognize that many variants of the sequences presented herein may exist or be constructed which would also function as antigens in the practice of the present invention. For example, with respect to amino acid sequences, variants may exist or be constructed which display: conservative amino acid substitutions; non-conservative amino acid substitutions; truncation by, for example, deletion of amino acids at the amino or carboxy terminus, or internally within the molecule; or by addition of amino acids at the amino or carboxy terminus, or internally within the molecule (e.g. the addition of a histidine tag for purposes of facilitating protein isolation, the substitution of residues to alter solubility properties, the replacement of residues which comprise protease cleavage sites to eliminate cleavage and increase stability, the addition or elimination of glycosylation sites, and the like, or for any other reason). Such variants may be naturally occurring (e.g. as a result of natural variations between species or between individuals); or they may be purposefully introduced (e.g. in a laboratory setting using genetic engineering techniques). All such variants of the sequences disclosed herein are intended to be encompassed by the teaching of the present invention, provided the variant antigen displays sufficient identity to the described sequences. Preferably, identity will be in the range of about 50 to 100%, and more preferably in the range of about 75 to 100%, and most preferably in the range of about 80 to 100% of the disclosed sequences. The identity is with reference to the portion of the amino acid sequence that corresponds to the original antigen sequence, i.e. not including additional elements that might be added, such as those described below for chimeric antigens. TABLE I Hookworm antigens, description, and corresponding SEQ ID NOS. SEQ ID NOs. /. cDNA open reading frame Source Antigen Description (Accession No.) (Accession No.) Necator americanus Na-ASP-1 secreted protein SEQ ID NO: 1 SEQ ID NO: 2 (AF079521) (AAD13340) Na-ASP-2 secreted protein SEQ ID NO: 82 SEQ ID NO: 69 (AY288089) (AAP41952) Na-ACE cholinesterase SEQ ID NO: 3 SEQ ID NO: 4 (AF36813) (AAN05636) Na-CTL C-lectin SEQ ID NO: 5 SEQ ID NO: 6 Na-APR-1 aspartic protease SEQ ID NO: 7 SEQ ID NO: 8 Na-APR-2 aspartic protease SEQ ID NO: 9 SEQ ID NO: 10 Na-CP-2 cysteine protease SEQ ID NO: 83 SEQ ID NO: 84 Na-CP-3 cysteine protease SEQ ID NO: 85 SEQ ID NO: 86 Na-CP-4 cysteine protease SEQ ID NO: 87 SEQ ID NO: 88 Na-CP-5 cysteine protease SEQ ID NO: 89 SEQ ID NO: 90 Na-MEP-1 metallo- SEQ ID NO: 91 SEQ ID NO: 92 endopeptidase Na-MTP-1 astacin protease SEQ ID NO: 111 SEQ ID NO: 112 Na-103 surface protein SEQ ID NO: 113 SEQ ID NO: 114 (SAA-1) Na-16 surface-associated SEQ ID NO:109 SEQ ID NO:110 antigen Ancylostoma duodenale Ad-ASP-1 secreted protein (AF077402) SEQ ID NO: 67 (AAD13339) Ad-ASP-2 secreted protein (AY288088) SEQ ID NO: 68 (AAP41951) Ancylostoma caninum Ac-TMP met protease SEQ ID NO: 11 SEQ ID NO: 12 inhibitor (AF372651) (AAK58952) Ac-MEP-1 metallo- SEQ ID NO: 13 SEQ ID NO: 14 endopeptidase (AF273084) (AAG29103) Ac-MEP-2 metallo- SEQ ID NO:101 SEQ ID NO:102 endopeptidase Ac-MTP-1 astacin protease SEQ ID NO: 15 SEQ ID NO: 16 (AY036056) (AAK62032) Ac-ASP-1 secreted protein SEQ ID NO: 17 SEQ ID NO: 18 (AF132291) (AAD31839) Ac-ASP-2 secreted protein SEQ ID NO: 19 SEQ ID NO: 20 (AF089728) (AAC35986) Ac-ASP-3 secreted protein SEQ ID NO: 21 SEQ ID NO: 22 (AY217004) (AA063575) Ac-ASP-4 secreted protein SEQ ID NO: 23 SEQ ID NO: 24 (AY217005) (AA063576) Ac-ASP-5 secreted protein SEQ ID NO: 25 SEQ ID NO: 26 (AY217006) (AA063577) Ac-ASP-6 secreted protein SEQ ID NO: 27 SEQ ID NO: 28 (AY217007) (AA063578) Ac-TTR-1 transthyretin SEQ ID NO: 29 SEQ ID NO: 30 Ac-TTR-2 transthyretin SEQ ID NO: 103 SEQ ID NO: 104 Ac-103 surface protein SEQ ID NO: 31 SEQ ID NO: 32 (SAA-1) (AY462062) (AAR25200) Ac-VWF surface lectin SEQ ID NO: 33 SEQ ID NO: 34 Ac-CTL C-lectin SEQ ID NO: 35 SEQ ID NO: 36 Ac-API aspartyl protease SEQ ID NO: 37 SEQ ID NO: 38 inhibitor Ac-MTP-1 astacin protease SEQ ID NO: 39 SEQ ID NO: 40 Ac-MTP-2 astacin protease SEQ ID NO: 41 SEQ ID NO: 42 Ac-MTP-3 astacin protease SEQ ID NO: 43 SEQ ID NO: 44 Ac-FAR-1 retinol binding SEQ ID NO: 45 SEQ ID NO: 46 Ac-KPI-1 protease inhibitor SEQ ID NO: 47 SEQ ID NO: 48 Ac-APR-1 aspartic protease SEQ ID NO: 49 SEQ ID NO: 50 Ac-APR-2 pepsinogen SEQ ID NO: 51 SEQ ID NO: 52 Ac-AP anticoagulant SEQ ID NO: 53 SEQ ID NO: 54 Ac-CP-1 cysteine protease SEQ ID NO: 97 SEQ ID NO: 98 Ac-CP-2 cysteine protease (U18912) (AAC46878) Ac-CYS cystatin SEQ ID NO: 99 SEQ ID NO: 100 Ac-GST glutathione S SEQ ID NO: 76 SEQ ID NO: 77 transferase Ac-16 surface-associated SEQ ID NO: 93 SEQ ID NO: 94 antigen Ancyclostoma ceylanicum Ay-ASP-1 secreted protein SEQ ID NO: 55 SEQ ID NO: 56 (AY136548) (AAN11402) Ay-ASP-2 secreted protein SEQ ID NO: 57 SEQ ID NO: 58 (AY288090) (AAP41953) Ay-MTP-1 astacin protease SEQ ID NO: 59 SEQ ID NO: 60 (AY136547) (AAN11401) Ay-API-1 aspartyl protease SEQ ID NO: 61 SEQ ID NO: 62 inhibitor Ay-TTR transthyretin-like SEQ ID NO: 63 SEQ ID NO: 64 Ay-16 surface-associated SEQ ID NO: 95 SEQ ID NO: 96 antigen Ay-APR-1 aspartic protease SEQ ID NO: 105 SEQ ID NO: 106 Ay-CP-2 cysteine protease (AF522068) (AAM82155) Ay-CYS cystatin SEQ ID NO:107 SEQ ID NO:108 The invention also encompasses chimeric antigens, for example, antigens comprised of the presently described amino acid sequences plus additional sequences which were not necessarily associated with the disclosed sequences when isolated but the addition of which conveys some additional benefit. For example, such benefit may be utility in isolation and purification of the protein, (e.g. histidine tag, GST, and maltose binding protein); in directing the protein to a particular intracellular location (e.g. yeast secretory protein); in increasing the antigenicity of the protein (e.g. KHL, haptens). All such chimeric constructs are intended to be encompassed by the present invention, provided the portion of the construct that is based on the sequences disclosed herein is present in at least the indicated level of homology. Those of skill in the art will recognize that it may not be necessary to utilize the entire primary sequence of a protein or polypeptide in order to elicit an adequate antigenic response to the parasite from which the antigen originates. In some cases, a fragment of the protein is adequate to confer immunization. Thus, the present invention also encompasses antigenic fragments of the sequences disclosed herein, and their use in vaccine preparations. In general, such a fragment will be at least about 10-13 amino acids in length. Those of skill in the art will recognize that suitable sequences are often hydrophilic in nature, and are frequently surface accessible. Likewise, with respect to the nucleic acid sequences disclosed herein, those of skill in the art will recognize that many variants of the sequences may exist or be constructed which would still function to provide the encoded antigens or desired portions thereof. For example, due to the redundancy of the genetic code, more than one codon may be used to code for an amino acid. Further, as described above, changes in the primary sequence of the antigen may be desired, and this would necessitate changes in the encoding nucleic acid sequences. In addition, those of skill in the art will recognize that many variations of the nucleic acid sequences may be constructed for purposes related to cloning strategy, (e.g. for ease of manipulation of a sequence for insertion into a vector, such as the introduction of restriction enzyme cleavage sites, etc.), for purposes of modifying transcription (e.g. the introduction of promoter or enhancer sequences, and the like), or for any other suitable purpose. All such variants of the nucleic acid sequences disclosed herein are intended to be encompassed by the present invention, provided the sequences display about 50 to 100% identity to the original sequence and preferably, about 75 to 100% identity, and most preferably about 80 to 100% identity. The identity is with reference to the portion of the nucleic acid sequence that corresponds to the original sequence, and is not intended to cover additional elements such as promoters, vector-derived sequences, restriction enzyme cleavage sites, etc. derived from other sources. The antigens of the present invention may be derived from any species of hookworm, examples of which include but are not limited to Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum and Ancylostoma duodenale. Examples of suitable hookworm antigens include but are not limited to Na-ASP-1, Na-ACE, Na-CTL, Na-APR-1, NA-APR-2, Ac-TMP, Ac-MEP-1, Ac-MTP-1, Ac-ASP-1, Ac-ASP-2, Ac-ASP-3, Ac-ASP-4, Ac-ASP-5, Ac-ASP-6, Ac-TTR-1, Ac-103, Ac-VWF, Ac-CTL, Ac-API, Ac-MTP-1, Ac-MTP-2, Ac-MTP-3, Ac-FAR-1, Ac-KPI-1, Ac-APR-1, Ac-APR-2, Ac-AP, Ay-ASP-1, Ay-ASP-2, Ay-MTP-1, Ay-API, and Ay-TTR. In some embodiments of the invention, the antigenic entity is an activation associated secretory protein, examples of which include but are not limited to Na-ASP-1, Ac-ASP-3, Ac-ASP-4, Ac-ASP-5, Ac-ASP-6, Ay-ASP-1, and Ay-ASP-2. In other embodiments of the invention, the antigenic moiety is a protease, examples of which include but are not limited to metalloproteases (e.g. Ac-MTP-2, Ac-MTP-3; cysteine proteases; aspartic proteases (e.g. Ac-APR-1 and Ac-APR-2); and serine proteases. In yet other embodiments of the invention, the antigen may be a lectin (e.g. Na-CTL, Ac-CTL). In other embodiments of the invention, the antigen may be a protease inhibitor (e.g. Ac-API-I, Ay-API-1, Ac-AP, Ac-KPI-1). In a preferred embodiment, the antigen utilized in the practice of the present invention is Ac-TMP, the DNA encoding sequence of which is given in FIG. 6A (SEQ ID NO: 11), and the amino acid sequence of which is given in FIG. 6B (SEQ ID NO: 12). In another preferred embodiment, the antigen utilized in the practice of the present invention is Ac-MEP-1, the DNA encoding sequence of which is given in FIG. 7A (SEQ ID NO: 13, and the amino acid sequence of which is given in FIG. 7B (SEQ ID NO: 14). In another preferred embodiment, the antigen utilized in the practice of the present invention is Ac-MTP-1, the DNA encoding sequence of which is given in FIG. 8A (SEQ ID NO: 15, and the amino acid sequence of which is given in FIG. 8B (SEQ ID NO: 16). Other preferred antigens include but are not limited to Na-CTL (SEQ ID NOS. 5-6); Na-APR-1 (SEQ ID NOS. 7-8); Na-APR-2 (SEQ ID NOS. 9-10); Ac-TMP (SEQ ID NOS. 1′-12); Ac-ASP-3 (SEQ ID NOS. 21-22); Ac-ASP-4 (SEQ ID NOS. 23-24); Ac-ASP-5 (SEQ ID NOS. 25-26); Ac-ASP-6 (SEQ ID NOS. 27-28); Ac-TTR-1 (SEQ ID NOS. 29-30); Ac-TTR-2 (SEQ ID NOS. 103-104) Ac-103 (SAA-1) (SEQ ID NOS. 31-32); Ac-VWF (SEQ ID NOS. 33-34); Ac-CTL (SEQ ID NOS. 35-36); Ac-API-I (SEQ ID NOS. 37-38); Ac-MTP-1 (SEQ ID NOS. 3940); Ac-MTP-2 (SEQ ID NOS. 4142); Ac-MTP-3 (SEQ ID NOS: 4344); Ac-KPI-1 (SEQ ID NOS: 4748); Ac-APR-1 (49-50); Ac-APR-2 (SEQ ID NOS: 51-52); Ay-ASP-1 (SEQ ID NOS: 55-56); Ay-ASP-2 (SEQ ID NOS: 57-58); Ay-MTP-1 (SEQ ID NOS: 59-60); Ay-API-1 (SEQ ID NOS: 61-62); Ay-TTR (SEQ ID NOS: 63-64); Na-ACE (SEQ ID NOS: 3 and 4); Na-ASP-1 (SEQ ID NOS: 1 and 2); Ac-MEP-1 (SEQ ID NOS: 13-14); Other preferred antigens for use in the practice of the present invention include Ad-ASP-1 (protein, SEQ ID NO: 67); Ad-ASP-2 (protein, SEQ ID NO: 68); Na-ASP-2 (protein, SEQ ID NO: 69; nucleotide, SEQ ID NO: 82); CP-2 antigens, e.g. Ac-CP-2 (Genebank Accession # U18912); Na-CP-2 (SEQ ID NOS: 83-84); Na-CP-3 (SEQ ID NOS: 85-86); Na-CP-4 (SEQ ID NOS: 87-88); Na-CP-5 (SEQ ID NOS: 89-90); Ac-CP-1 (SEQ ID NOS: 97-98); Ac-CP-2; Ay-CP-2; GST antigens, e.g. Ac-GST (protein SEQ ID NO: 77, nucleotide SEQ ID NO: 76); Na-MEP-1 (SEQ ID NOS: 91-92); Na-MTP-1 (SEQ ID NOS: 111-112); Na-103 (SAA-1) (SEQ ID NOS: 113-114); Na-16 (SEQ ID NOS: 109-110; Ac-MEP-2 (SEQ ID NOS: 101-102); Ac-CYS (SEQ ID NOS: 99-100); Ay-CYS (SEQ ID NOS: 107-108); Ac-16 (SEQ ID NOS: 93-94); Ay-16 (SEQ ID NOS: 95-96); Ay-APR-1 (SEQ ID NOS: 105-106). The present invention provides compositions for use in eliciting an immune response which may be utilized as a vaccine against hookworm. By “eliciting an immune response” we mean that an antigen stimulates synthesis of specific antibodies at a titer of about >1 to about 1×106 or greater. Preferably, the titer is from about 10,000 to about 1×106 or more, and most preferably, the titer is greater than 1×106, and/or cellular proliferation as measured by, for example, 3H thymidine incorporation. By “vaccine” we mean an antigen that elicits an immune response that results in a decrease in hookworm burden of a least about 30% in an organism in relation to a non-vaccinated (e.g. adjuvant alone) control organism. Preferably, the level of the decrease is about 50%, and most preferably, about 60 to about 70% or greater. The present invention provides compositions for use in eliciting an immune response which may be utilized as a vaccine against hookworm. The compositions include a substantially purified hookworm antigen or variant thereof as described herein, and a pharmacologically suitable carrier. The preparation of such compositions for use as vaccines is well known to those of skill in the art. Typically, such compositions are prepared either as liquid solutions or suspensions, however solid forms such as tablets, pills, powders and the like are also contemplated. Solid forms suitable for solution in, or suspension in, liquids prior to administration may also be prepared. The preparation may also be emulsified. The active ingredients may be mixed with excipients which are pharmaceutically acceptable and compatible with the active ingredients. Suitable excipients are, for example, water, saline, dextrose, glycerol, ethanol and the like, or combinations thereof. In addition, the composition may contain minor amounts of auxiliary substances such as wetting or emulsifying agents, pH buffering agents, and the like. In addition, the composition may contain other adjuvants. If it is desired to administer an oral form of the composition, various thickeners, flavorings, diluents, emulsifiers, dispersing aids or binders and the like may be added. The composition of the present invention may contain any such additional ingredients so as to provide the composition in a form suitable for administration. The final amount of hookworm antigen in the formulations may vary. However, in general, the amount in the formulations will be from about 1-99%. The vaccine preparations of the present invention may further comprise an adjuvant, suitable examples of which include but are not limited to Seppic, Quil A, Alhydrogel, etc. The preparations of the present invention may contain a single hookworm antigen. Alternatively, more than one hookworm antigen may be utilized in a preparation, i.e. the preparations may comprise a “cocktail” of antigens. In a preferred embodiment, such a cocktail will contain two or more antigens, and will be a combination of a larval stage antigen and an adult stage antigen. Examples of suitable larval stage antigens include but are not limited to ASP-2, MTP-1, 103 (SAA-1), 16 and GST. Examples of suitable adult stage antigens include but are not limited to APR-1, CP-2, GST, MEP-1, APR-2, and TMP. GST is an antigen that is present at both the larval and adult stage. The antigens utilized in the cocktail may be from any species. However, in preferred embodiments of the invention, the antigens will be antigens derived from a human hookworm source such as Na-Asp-2, Na-APR-1, Na-CP-2, Na-GST, Na-MEP-1, Ad-Asp-2, Ad-APR-1, Ad-CP-2, Ad-GST, Ad-MEP-1, Na-MTp-1, Ad-MTP-1, Na-103 (Na-SAA), Ad-103 (Ad-SAA-1), Na-16, and Ad-16. Preferably, the cocktail will contain at least two antigens derived from a human hookworm source, at least one larval stage and at least one adult stage, such as, for example, either Na- or Ad-: Asp-2 APR-1; Asp-2 and CP-2; Asp-2 and GST; Asp-2 and MEP-1. The present invention also provides a method of eliciting an immune response to hookworm and methods of vaccinating a mammal against hookworm. By eliciting an immune response, we mean that administration of the antigen causes the synthesis of specific antibodies (at a titer in the range of 1 to 1×106, preferably 1×103, more preferable in the range of about 1×103 to about 1×106, and most preferably greater than 1×106) and/or cellular proliferation, as measured, e.g. by 3H thymidine incorporation. The methods involve administering a composition comprising a hookworm antigen in a pharmacologically acceptable carrier to a mammal. The vaccine preparations of the present invention may be administered by any of the many suitable means which are well known to those of skill in the art, including bu not limited to by injection, orally, intranasally, by ingestion of a food product containing the antigen, etc. In preferred embodiments, the mode of administration is subcutaneous or intramuscular. The present invention provides methods to elicit an immune response to hook worn and to vaccinate against hookworm in mammals. In one embodiment, the mammal is a human. However, those of skill in the art will recognize that other mammals exist for which it would also be of benefit to vaccinate against hookworm, i.e. the preparations may also be used for veterinary purposes. Examples include but are not limited to companion “pets” such as dogs, cats, etc.; food source, work and recreational animals such as cattle, horses, oxen, sheep, pigs, goats, and the like. Those of skill in the art will recognize that, in general, in order to vaccinate (or elicit an immune response in) a species of interest (e.g. humans) against hookworm, the antigen which is utilized will be derived from a species of hookworm which parasitizes the species of interest. For example, in general, antigens from Necator americanus may be preferred for the immunization of humans, and antigens from Ancylostoma caninum may be preferred for the immunization of dogs. However, this may not always be the case. For example, Ancylostoma caninum is known to parasitize humans as well as its primary canine host. Further, cross-species hookworm antigens may sometimes be highly effective in eliciting an immune response in a non-host animal, i.e. in an animal that does not typically serve as host for the parasite from which the antigen is derived. Rather, the measure of an antigen's suitability for use in an immune-stimulating or vaccine preparation is dependent on its ability to confer protection against invasion and parasitization by the parasite as evidenced by, for example, hookworm burden reduction or inhibition of hookworm associated blood loss (e.g. as measured by hematocrit and/or hemoglobin concentration. For example, for use in a vaccine preparation, an antigen upon administration results in a reduction in worm burden of at least about 30%, preferably at least about 50%, and most preferably about 60 to about 70%. In one embodiment of the present invention, a method for enabling vaccination of a patient against infectious diseases is provided. The method involves chemically treating hookworm infection to a degree sufficient to increase lymphocyte proliferation, followed by vaccinating the patient against said infectious disease. The method is based on evidence provided in Example 10 which shows that hookworm infestation causes anergy to hookworm and possibly other antigen stimulation. Therefore, by chemically treating hookworm infected patients prior to vaccination against hookworm or any infectious agent, the response to the vaccination will be improved. Examples of infectious diseases against which vaccination outcomes may be improved include but are not limited to HIV, tuberculosis, malaria, and routine childhood vaccinations (e.g. measles, tetanus, diphtheria, pertussis, polio, and the like). Examples of agents with which hookworm may be chemically treated include but are not limited to albendazole and other antihelminthic drugs. Certain of the antigens described herein may also be useful in the vaccination against other parasites, for example (including but not limited to) Schistosoma sp and soil transmitted parasites such as Ascaris sp and Trichuris sp. This may be due to the potential cross reactivity between the hookworm antigens and antigens from these species. Certain of the antigens described herein may also be useful in the treatment of other neoplastic, autoimmune, and cardiovascular conditions, as well as for the treatment of pro-inflammatory states. Such uses of other hookworm antigens have been described in, for example, U.S. Pat. No. 5,427,937 to Capello et al. and U.S. Pat. No. 5,753,787 to Hawdon. The present invention also provides the following nucleic acid and amino acid sequences: SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 47, SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 51, SEQ ID NO: 52, SEQ ID NO: 55, SEQ ID NO: 56, SEQ ID NO: 57, SEQ ID NO: 58, SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 62, SEQ ID NO: 63, and SEQ ID NO: 64. The sequences represent cDNA sequences and the amino acid sequences (open reading frames) which they encode. While the sequences themselves are being claimed, other sequences with a high level of identity in comparison to those described are also contemplated, e.g. sequences having at least about 65 to 100% identity, or preferably about 75 to 100% identity, or most preferably at least about 80 to 100% identity, to the sequences that are given. In particular, the sequences for Ac-APR-2 (SEQ ID NOS: 51 and 52) and Ay-TTR-1 (SEQ ID NOS: 63 and 64) are partial sequences which represent the majority of the antigen sequence. Thus, the present invention encompasses the entire Ac-APR-2 antigen and the entire Ay-TTR-1 antigen. Further, those of skill in the art will recognize that the Ay-TTR-1 and Ay-TTR-2 antigens which are provided in the present application are representative of the Ay-TTR family of antigens present in many species of nematodes. As such, an Ay-TTR antigen from any nematode is intended to be encompassed by the present invention. In particular, any Ay-TTR antigen derived from a hookworm species including but not limited to Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, and Ancylostoma duodenale, are encompassed. Additional sequences that are provided by the present invention include: SEQ ID NO: 76 and SEQ ID NO: 77, representing Ac-GST cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 83 and SEQ ID NO: 84, representing Na-CP-2 cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 85 and SEQ ID NO: 86, representing Na-CP-3 cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 87 and SEQ ID NO: 88, representing Na-CP-4 cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 89 and SEQ ID NO: 90, representing Na-CP-5 cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 91 and SEQ ID NO: 92, representing Na-MEP-1 cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 93 and SEQ ID NO: 94, representing Ac-16 cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 95 and SEQ ID NO: 96, representing Ay-16 cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 97 and SEQ ID NO: 98, representing Ac-CP-1 cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 99 and SEQ ID NO: 100, representing Ac-CYS cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 101 and SEQ ID NO: 102, representing Ac-MEP-2 cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 103 and SEQ ID NO: 104, representing Ac-TTR-2 cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 105 and SEQ ID NO: 106, representing Ay-APR-1 cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 107 and SEQ ID NO: 108, representing Ay-Cys cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 109 and SEQ ID NO: 110, representing Na-16 cDNA and corresponding amino acid sequence, respectively; SEQ ID NO: 111 and SEQ ID NO: 112, representing Na-MTP-1 cDNA and corresponding amino acid sequence, respectively; and SEQ ID NO: 113 and SEQ ID NO: 114, representing Na-SAA-1 cDNA and corresponding amino acid sequence, respectively. EXAMPLES Example 1 Molecular Cloning and Purification of Ac-TMP Materials and Methods Immunoscreening of adult A. caninum library Preparation of anti-A. caninum secretory product antibody. One hundred living adult stage Ancylostoma caninum hookworms were recovered from the intestines of an infected dog, at necropsy (6 weeks post-infection), as described previously (Hotez and Cerami, 1983). The adult worms were washed three times in sterile PBS, then maintained in 15 ml RPM 1640 containing 25 mM HEPES, 100 units/ml of ampicillin and 100 μg/ml streptomycin at 37C (5% CO2) for 24 hours. The supernatant was collected, concentrated with PEG6000, and dialyzed against 1 L phosphate buffered saline (pH 7.2) overnight at 4° C. Following dialysis, the secreted products were centrifuged at 10,000×g for 10 min, and the supernatant was recovered. A rabbit was immunized by subcutaneous injection with the hookworm-secreted proteins (400 ug) emulsified with complete Freund's adjuvant. Subsequently, the rabbit was immunized at two week intervals with the same quantity of hookworm secreted proteins emulsified with incomplete Freund's adjuvant for a total of three immunizations. The final bleed was obtained 10 days after the final immunizations, and the serum was separated from whole blood and stored at −20° C. Construction of the cDNA expression ZapII (Stratagene, La Jolla Calif.) library was reported previously (Capello et al., 1996)). An estimated 5×105 plaques were screened with the rabbit anti-A. caninum adult secretory product antibody according to manufacturer's instructions. Briefly, 5×104 plaques were plated on an LB agar plate. A. caninum antigen expression was induced by covering the plaques with nitrocellulose membranes soaked with 10 mM IPTG. Four hours after incubation at 37° C., the membranes were lifted, blocked with 5% non-fat milk in PBS, and then incubated with the rabbit antibody (1:500 dilution) for 1 hour at 24° C. The membranes were washed three times with PBS buffer containing 0.1% Tween-20 (PBS-Tween) and then incubated with horseradish peroxidase conjugated goat anti-rabbit IgG (Sigma) at a 1:1000 dilution at 24° C. for another hour. The membranes were washed again three times with PBS-Tween and then developed with 3,3′-diaminobenzidine (DAB) substrate and hydrogen peroxide. The putative positive clones were scored and isolated for secondary screening. The immunopositive clones were excised into pBluscript phage according to manufacturer's instructions (Stratagene), Phagemid DNA was extracted using the alkaline lysis method (Qiagen) and double strand sequencing was performed using flanking vector primers (T3 and T7). Nucleotide and deduced amino acid sequences were compared to existing sequences in GenBank by BLAST searching. ESEE 3.1 software was used for sequence analysis. Reverse Transcription Polymerase Chain Reaction (RT-PCR) Amplification. RT-PCR was used to determine the developmental stage specificity of Ac-tmp mRNA transcription. A. caninum eggs, L1 and L2 larval stages, and L3 infective larvae were obtained as described previously (Hawdon et al, 1999). The total RNA was isolated from each life history stage using TRIzol reagent (GIBCO BRL). Single-strand cDNA was synthesized using oligo d(T) primer and MMLV-RT(GIBCO BRL). Specific primers (TIMP3′-1HR and TIMP5′-2ER based on the sequence of Ac-tmp from 60 bp to 440 bp were used to amplify the Ac-tmp cDNA. PCR reaction parameters were comprised of 94° C. denaturing for 1 min, 55° C. annealing for 1 min, 72C extension for 2 min. A total 30 cycles were performed. Purification of Ac-TMP natural product. Optimization of semi-preparative reverse phase chromatographic conditions for the fractionations of A. caninum adult secretory products was carried out on a 510 HPLC system (Waters), equipped with a 490 E multiwavelength detector with a semi-preparative flow-cell, set at 214, 280, 260 and 254 mm and a 250 mm×4.6 I.D. YMC-Pack Protein-RP, 200Å, 5 μm C4 Column (Waters). The adult A. caninum secretory products used as starting material were collected over 15 hr from 1260 adult hookworms in 15 ml RPMI 1640 containing 25 mM HEPES, 100 units/ml ampicillin, 100 μg/ml streptomycin and 100 μg/ml gentamicin at 37° C. The supernatant was concentrated by ultrafiltration in a Centricon-3 microconcentrator (Amicon) to 0.3 vol. before centrifugation for 1 hr at 7,500×g. Approximately 0.6 mg of the parasite secretory protein was chromatographed. Eluent A was 0.01% Trifluoroacetic acid (TFA) in water, and eluent B was 0.01% TFA in acetonitrile. A 40-min linear aradient from 0-80% B was run at a flow-rate of 1 ml/min. Fractions of 0.5 min were collected, lyophilized, and were used for further purification and analysis by SDS-PAGE (Laemmli, 1970). For SDS-PAGE, 2 μl of secretory products as well as the 10 μl of HPLC isolated fraction number 51 were mixed with the same volume of 2×SDS-PAGE sample buffer (4% SDS, 2.5% 2-mercapto ethanol, 15% glycerol) and boiled for 5 min. The samples were run on a 4-20% gradient SDS-PAGE gel at 100 V for 2 hours. The gel was stained with silver according to manufacturer's instruction (BIO-RAD). RP-HPLC of Fraction 51, the fraction that contained the most abundant A. caninum secretory protein from the semi-preparative separation, was carried out on a 510 HPLC system equipped as described above using a 250 mm.×3.0 I.D. YMC protein RP, 200 A, 5 μm C4 column. Eluent A was 0.01% TFA in water, and B was 0.01% TFA in acetonitrile. A 30-min linear gradient from 0-60% B was run at a flow-rate of 1 ml/min. Fractions of 0.5 min were collected and lyophilized. The major protein peak collected from this separation was subjected to amino acid sequence analysis and SDS-PAGE (Laemmli, 1970). Amino acid sequence analysis based on the Edman degradation of protein was performed on procise 494 model protein sequencer (Applied Biosystems) equipped with a 785A programmable detector and a 140C pump system, by ProSeq, Inc. (Boxford Mass.). The sequencer products were identified using standard procise 610A software. To confirm that the N-terminal sequence corresponded to Ac-TMP, degenerate oligonucleotide primers were synthesized in both orientations that corresponding to the partial N-terminal peptides sequence of fraction number 51. Paired flanking degenerate vector primers were used to amplify the product from DNA obtained from the adult cDNA library constructed in ZapII. The “hot start” PCR conditions were 10 mM Tris-HCl (pH 8.5) containing 50 mM KCl, 2.0 mM MgCl2, 0.2 mM of each dNTP, and 1 μl cDNA library, in 20 μl reaction. The reactions were heated at 94° C. for 5 min, then lowered to 85° C. for 5 min, then 1 unit of Taq DNA polymerase (GIBCO BRL) was added. This was followed by 30 cycles of 1 min of denaturation at 94° C., 1 min of annealing at 55° C., and 2 min of extension at 72° C. The PCR products were run on an agarose gel and stained with ethidium bromide. The PCR products were gel purified with the QIAEX H Gel Extraction kit (Qiagen, Valencia, Calif.), and sequenced. Results for Example 1 Ac-TMP cDNA. Ac-TMP cDNA was cloned from an adult hookworm cDNA library by immunoscreening with rabbit antibody directed against whole A. caninum adult secretory products. Two positive identical clones were isolated. The full-length cDNA consists of 559 bps (SEQ ID NO: 11) encoding an open reading frame (ORF) of 140 amino acids (SEQ ID NO: 12) and a poly-A tail at the 3′ end. The predicted ORF has a calculated molecular weight of 16,100 daltons and a theoretical pI of 7.55. There is a hydrophobic signal peptide sequence with a signal peptidase cleavage site between amino acids 16 and 17. Ac-TMP has a signature N terminal Cys-X-Cys sequence immediately following the signal peptide. One putative N linked glycosylation site (N-X-T) exists between amino acids 119 and 122 (FIG. 6B). GenBank database searching revealed that the predicted amino acid sequence of this molecule shares 33 percent identity and 50 percent similarity to the N-terminal domain of human tissue inhibitor of metalloproteinase 2 (TIMP-2). Both Ac-TMP and a putative TIMP from the free-living nematode Caenorhabditis elegans are comprised of a single domain and lack a second, C-terminal domain that is characteristic of vertebrate TIMPs (data not shown). RT-PCR amplification. To identify the life-history stage specific expression of Ac-TMP, mRNAs were extracted from different developmental stages of A. caninum and reverse transcribed to cDNA with Ac-TMP specific primers. RT-PCR produced a 380 bp specific band that was only amplified from adult cDNA. No amplification was seen from the cDNA of eggs, Li-L2 and L3 life history stages. Amplification of A. caninum genomic DNA revealed two bands suggestive of a possible intron or the existence of a second, related Ac-TMP gene (data not shown). Identification of Ac-TMP in secretory products of A. caninum adult worm. To confirm that Ac-TMP is released by adult A. caninum hook-worms, the protein was identified in and purified from parasite secretory products via RP-HPLC. Each of the major peaks were subjected to amino acid sequence analysis as part of a larger A. caninum proteomics study (data not shown). The peak of protein corresponding to “Fraction 51” was selected for further study and re-chromatographed. Fraction 51 was comprised of one predominant band after silver staining that migrated with an apparent molecular weight of Mr=16,000. The N-terminal peptide sequence (20 amino acids) of this fraction was an identical match with the sequence of the predicted ORF of Ac-TMP after the predicted signal peptidase cleavage site. Based on the calculated area under the curve of HPLC peak 51 relative to the total area of the entire secretory product profile, Ac-TMP was determined to comprise approximately 6.3 percent of the total A. caninum secretory products. This identified the molecule as one of the most abundant proteins released by adult A. caninum. The abundance of Ac-TMP in hookworm secretory products was confirmed by visual inspection on SDS-PAGE. Paired degenerate primers based on the sequence of the first seven amino acids were used to construct PCR products from the adult hookworm cDNA library. DNA sequence of the PCR products confirmed the identity to Ac-TMP cDNA (data not shown). This example demonstrates that TMP is the most abundant protein secreted by hookworms and that the protein has been cloned and expressed, and the recombinant protein isolated. Example 2 Molecular Cloning and Characterization of Ac-mep-1 Materials and Methods. Parasites. A. caninum parasites were maintained in beagles as described previously (Schad 1982). Third stage infective larvae (L3) were isolated from charcoal copro-cultures and stored in BU buffer (Hawdon et al. 1995). Adult A. caninum worms were collected from infected dogs upon necropsy. These worms were washed three times in PBS, snap frozen in liquid nitrogen, and stored at −80□C. Nucleic acids Genomic DNA was isolated from adult A. caninum by standard methods (Ausubel et al. 1993). A. caninum RNA was isolated by grinding previously frozen (−80□C) adult worms in the presence of Trizol reagent (Gibco BRL) and following manufacturers protocol. cDNA was prepared from RNA by the ProSTAR First Strand RTPCR Kit (Stratagene) according to the manufacturer's instructions. A. caninum genomic and cDNA libraries An A. caninum genomic DNA library was constructed as follows: 30 ug A. caninum genomic DNA was partially digested (37 □C for 5 min) by 8 U Sau3A restriction enzyme (NEB) in a 100 ul volume with recommended buffer. The digested DNA was then ethanol precipitated and pelleted by standard methods. The resulting pellet was dried, dissolved in water, and ligated into the Lambda-FIXII vector (Stratagene) according to manufacture's protocol. This ligation reaction was then packaged with Gigapack Gold packaging extract (Stratagene) and amplified. An A. caninum adult cDNA library was constructed previously (Capello et al. 1996) in lambda ZAPII (Stratagene) vector. Metalloprotease cloning Cloning the Ac-mep-1 cDNA began with PCR on adult hookworm library cDNA using a degenerate primer and oligo-dT. A degenerate primer was designed against a conserved sequence containing the zinc binding motif observed in an BLAST alignment of two hypothetical zinc metalloprotease genes from C. elegans (GenBank™ accession numbers T22668 and Q22523) The reaction conditions were as follows: 85 ng template DNA, 1× thermophillic DNA buffer (Promega), 2.5 mM MgCl2, 0.2 mM dNTP's, 2 uM each primer, 1 U taq DNA polymerase (Promega), in 20 μl total volume. The reactions were cycled at 94° C. for 1 min, 55C for 1 min, and 72C for 1 min 35 times. This PCR yielded a fragment which when cloned (pGEM-T, Promega) and sequenced represented 458 bp (including 21 residues of the poly A tail) of the 3 Ac-mep-1 cDNA (Clone MP-1). Utilizing the MP-1 as the basis for specific primer design additional sequence of Ac-mep-1 (Clone MP-2) was identified by PCR on library DNA with T3 (vector) and MEP-R1 gene specific primers. Reactions were conducted on serial dilutions of library DNA until a unique product was amplified and then cloned. Reaction conditions were as described above. In a similar clone MP-3 was amplified with T3 and MEP-R2 primers. The 5′-RACE kit from GibcoBRL was employed to identify the 5′ end of Ac-mep-1. Briefly, first strand cDNA was produced in a reverse transcription reaction with the Ac-mep-1 specific primer RACE-R1 on freshly prepared RNA. This cDNA was then poly C tailed at its 3′ end with terminal deoxytransferase and used as template in a PCR reaction with anchor primer AAP (GibcoBRL) and gene specific reverse primer MEP-R2. The resulting products were diluted and used as template in a hemi-nested PCR reaction with anchor primer UAP (GibcoBRL) and gene specific primer MEP-R3. The PCR product generated was cloned and termed MP-4. More 5′ sequence was identified from a genomic DNA clone (G-MEP) of Ac-mep-1 like sequence. Multiple clones were sequenced to confirm the Ac-mep-1 cDNA and the full length coding region of Ac-mep-1 was PCR amplified (clone FL-1) under the conditions described above as a single fragment utilizing suitable primers. Sequence analysis Alignment of the partial Ac-mep-1 clones was conducted using MEGALIGN software from DNASTAR Inc. (version 3.7.1). BLAST analysis of the initial sequences used for degenerate primer design and the predicted open reading frame (ORF) of Ac-mep-1 was conducted using the National Center for Biotechnology Information BLAST utility. Sequence analysis of Ac-mep-1 was conducted using the Curatools sequence analysis utility (Curagen Corp., New Haven, Conn.). The FGENESH gene finder utility (CGG WEB server (genomic.sanger.ac.uk) with settings to analyze C. elegans DNA was utilized for gene predictions from the genomic DNA clone G-MEP. Identification of potential exon sequences in GMEP was accomplished with the Wise2 sequence analysis utility (sanger.ac.uk/Software Wise2/). Northern blotting Northern blot analysis was conducted on Trizol (GibcoBRL) isolated total RNA from ten adult worms. This RNA was fractionated on a 1.2% formaldehyde gel and blotted to Hybond-N membrane (Amersham) by standard methods. The blot was probed with a 32P random prime labeled DNA fragment representing bp 780-2688 of the Ac-mep-1 cDNA. Developmental RT-PCR RT-PCR was used to investigate Ac-mep-1 transcription in A. caninum life history stages. For these reactions cDNA from egg, L1, non-activated and activated L3 and adult worms were tested with Ac-mep-1 specific primers MEP-F1 and MEP-R1. The quality if these cDNAs was verified in separate reactions using primers PKA-F and PKA-R, which are specific for A. caninum protein kinase A (Hawdon et al. 1995). The reaction conditions were identical to those defined in Section 2.4. Anti-Ac-mep-1 antibody A cDNA fragment representing 610 amino acids from the C-terminal portion of Ac-mep-1 was amplified from the adult A. caninum cDNA lambda library by PCR using suitable primers. This fragment was T/A cloned into pGEM (Promega) from which it was cloned into pET28c expression vector (Novagen) at the HindIII site by standard methods (Sambrook and Russell, 2001). Bacterial protein expression of truncated Ac-mep-1 (tAc-MEP-1) was induced by the addition of 1 mM IPTG to a culture of BL21 (DE3)PlysS (Stratagene) cells transformed with the tAc-MEP-1/pET28c construct. The expressed protein was insoluble. In order to purify tAc-mep-1 the induced cell pellets were frozen (BL21(DE3)PlysS cells lyse after freezing), resuspended in one-tenth vol. of 50 mM tris pH 8.0, 2 μM EDTA, sonicated until no longer viscous and then centrifuged at 12, 000×g for 15 min (Sorvall RC5B, GSA rotor). The resulting pellet was resuspended in 15 ml 1% SDS, 0.5% B-mercaptoethanol, sonicated, boiled for 5 min, and then incubated at room temperature for 2 h. Undissolved debris was removed by repeat centrifugation. The supernatant was dialyzed exhaustively against phosphate buffered saline (pH 7.4) to remove the BME. The protein was purified on HisBind (Novagen) nickel resin affinity column according to the manufacturer's protocol without denaturant. Groups of five male Balb/c mice (6-week-old) were immunized intraperitoneally with 20 ug of alum-precipitated tAc-MEP-1 or alum alone as control. The mice were subsequently boosted twice at 2-week intervals. One week after the third and final immunization, sera was collected, pooled, and used as a primary antibody in the western blot and immunostaining analysis. Western blotting Proteins separated by 10% SDS-PAGE were transferred to methanol charged Immobilon-P PVDF membranes (Millipore) in transfer buffer (39 mM glycine, 48 mM tris base, 0.037% SDS, pH 8.3) for 18 h at 30V. The membrane was blocked in 5% nonfat milk in PBS (blocking buffer), for 1 h at room temperature (RT) with gentle shaking and incubated with E. coli absorbed primary mouse anti-tAc-MEP-1 antibody (1:1500) diluted in blocking buffer for 1 h at RT. The membrane was then washed three times in blocking buffer (10 min each), and incubated for 1 h at RT with horseradish peroxidase-conjugated goat anti-mouse IgG secondary antibody (1:5000) in blocking buffer with shaking. Finally, the membrane was washed three times in PBS for 15 min and developed with Renaissance (NEN Life Science Products) chemiluminescent reagents. Immunolocalization Adult A. caninum worms were paraffin embedded and sectioned by standard methods. In situ immunolocalization of Ac-MEP-1 was accomplished by incubating de-parrafinized worm sections in a 1:100 dilution (in PBS, pH 7.4) of mouse anti-tAc-MEP-1 or control sera (see above) for 1 h at RT. The sections were washed three times in PBS and incubated in a 1:200 dilution of goat anti-mouse IgG at 25° C. for 1 h followed by washing in PBS (three times). Sections were then visualized with a Olympus IX-50 inverted fluorescence microscope (U-MWIG filter) and photographed. Results for Example 2 cDNA structure of Ac-mep-1 The cloning strategy employed in obtaining the complete coding sequence of Ac-mep-1 was as follows: About 2.6 kb of the Ac-mep-1 transcript was identified by sequencing degenerate PCR clone MP-1, PCR derived clones MP-2, MP-3 and the 5′ RACE clone MP-4. Although there was a methionine codon close to the 5′ end of the RACE product, this codon was preceded by 58 in-frame amino acids that contained no stop, suggesting that MP-4 did not represent the actual 5′ end of Ac-mep-1. In addition, we have been unable to obtain a cDNA clone (by PCR) that included a spliced leader sequence. Therefore, G-MEP, a genomic DNA clone of Ac-mep-1 like sequence (98.7% exon identity), was examined with a gene prediction program for C. elegans DNA and a different potential transcription start site than was identified by 5′ RACE was identified. This prediction extended 158 bp beyond the 5′ RACE sequence and increased the deduced coding region by 91 amino acids. Utilizing this prediction the entire coding region of Ac-mep-1 was amplified as a single product of 2.7 kb product and the clone was confirmed by partially sequencing both its ends. The total length of the Ac-mep-1 transcript is ˜2.8 kb as verified by Northern blot (non-coding portions of the 5′ and 3′ ends were not amplified in the full length PCR). The deduced amino acid sequence of this transcript encodes a single ORF of 870 amino acids with four potential N-linked glycosylation sites (predicted pI=5.5, m.w.=98.7 kDa). The N-terminal amino acids of Ac-MEP-1 comprise a hydrophobic signal peptide sequence with a predicted cleavage after residue 22 (see FIG. 7B). Two signature zinc-binding motifs characteristic of the Endopeptidase 24.11 family of metalloproteases (Hooper, 1994) were identified. Ac-mep-1 is 66% similar and 48% identical to a metalloprotease (Hc-MEPlb) from the related trichostrongyle blood feeding nematode H. contortus. It is also equally similar to a metalloprotease (T25B6.2) from the non-parasitic nematode C. elegans (Gen-Bank™ T28906). Fourteen cysteine residues are highly conserved between these three molecules. Two additional cysteines (only one is conserved) are present in both Ac-MEP-1 and Hc-MEP lb. Northern blot and developmental analysis of Ac-mep-1 expression Northern blot analysis reveals a single mRNA transcript of approximately 2.8 kb in adult hookworm mRNA (not shown). RT-PCR was employed to investigate the developmental specificity of Ac-mep-1 transcription. Of the cDNAs tested it was possible to identify transcription only in the adult stage of the parasite and not in hookworm eggs, L1 or activated and non-activated L3 larvae. In contrast, positive control PCR conducted on the same cDNAs with primers specific for A. caninum protein kinase A revealed amplification from all template cDNAs. Thus, Ac-mep-1 appears to be expressed exclusively in adult worms. Western blot analysis and immunolocalization of Ac-mep-1 in adult worm sections By western blotting, the mouse anti-MEP-1 antiserum strongly recognizes adult A. caninum proteins of 90 and 100 kDa. Immunohistochemical analysis of adult worm sections localizes Ac-mep-1 to the microvillar surface of the hookworm gut. The antiserum reacts strongly to the gut microvilli in sections of adult worm as compared with sections incubated with control sera. Weaker staining in the tegument of the adult worm was also occasionally noted. Although the function of Ac-MEP-1 is not known, its location along the microvillar surface of the parasite gut would suggest that the enzyme is in direct contact with the blood meal, and may, therefore, have a role in nutrient digestion. This example demonstrates that MEP-1 is an important enzyme which allows hookworms to digest blood, and therefore is an attractive vaccine target. The recombinant MEP-1 protein has been cloned and expressed. Example 3 AC-MTP Antigen Studies Infective third-stage Ancylostoma hookworm larvae (L3) release a zinc-dependent metalloprotease that migrates with an apparent molecular weight of 50 kDa (Hawdon et al 1995a). The enzyme is released specifically in response to stimuli that induce feeding and development in the L3 (Hawdon et al, 1995b), and probably functions either in parasite skin and tissue invasion or ecdysis (Hotez et al, 1990). Because of its role in parasite-derived tissue invasion and molting, an anti-enzyme antibody response directed against Ac-MTP-1 might block larval migrations and parasite entry into the intestine. Ac-MTP-I is stage specific, and released by hookworm L3activated under hostlike conditions to resume feeding in vitro. Release of Ac-MTP-I during activation makes this molecule an attractive vaccine target. Example 3A Isolation of a cDNA from an A. caninum L3expression Library that Encodes a Zinc-Metalloprotease (Ac-mtp-1) of the Astacin Family. Material and Methods Antisera: Sera used for immunoscreening of the A. caninum L3 expression library were collected from 5 residents of Nanlin county in Anhui Province, China, under an IRB-approved human investigations protocol. Ancylostoma duodenale is the predominant hookworm in this region, with a ratio of A. duodenale to Necator americanus of greater than 20:1 based on the recovery of larval and adult hookworms from infected patients (Yong et al. 1999). Sera were obtained from Anhui residents who had high titers of circulating antibodies to A. caninum L3 whole lysate antigens, as described elsewhere (Xue et al., 2000). Two of the residents were hookworm egg-negative, whereas the remaining 3 harbored quantitative fecal egg counts of less than 400 eggs per gram of feces. Because of their high antibody titer and low intensity of infection, these individuals were considered putatively resistant, and their sera were pooled and used for immunoscreening. Negative control sera were collected from college students in Shanghai. Expression library screening: An A. caninum (Baltimore strain) L3 cDNA library constructed in X ZapII (Stratagene, La Jolla, Calif.) (Hawdon et al. 1995) was screened using the pooled antisera according to the manufacturer's instructions. Briefly, 5×104 plaques were induced to express protein by applying a nitrocellulose membrane soaked in 10 mM IPTG for 4 hr at 37 C. Following incubation, the membrane was incubated in 5% non-fat dry milk in PBS for 1 hr. The blocked membrane was incubated with a 1:100 dilution of pooled human sera in PBS for 1 hr at 22 C, washed 3 times in PBS for 10 min at 22 C, and incubated with a 1:1000 dilution of horseradish peroxidase conjugated anti-human IgG (Sigma, St. Louis Mo.). The membrane was developed with substrate of 3,3′-diaminobenzidine (DAB) and 0.015% hydrogen peroxide. Positive plaques were subjected to several rounds of plaque purification by re-plating and re-screening. Plasmids were rescued by in vivo excision (Short and Sorge, 1992) and both strands sequenced using primers complementary to flanking vector sequence. Nucleotide and deduced amino acid sequences were compared to existing sequences in the GeneBank database by BLAST searching (Altschul et al., 1997). Cloning of full-length Ac-MTP cDNA: All of the positive clones isolated were truncated at the 5′ end. To obtain the 5′ end, a PCR using a gene specific primer P I and a primer corresponding to the conserved nematode spliced leader was used to amplify the 5′ end from first strand cDNA of A. caninum L3. Twenty μL reactions containing 100 ng of each primer, 1 U of Taq polymerase (Promega, Madison Wis.), and 1 μL of cDNA was denatured for 2 min at 95 C, followed by 30 cycles of 1 min at 94 C, 1 min at 55 C, and 2 min at 72 C. Amplicons were gel purified and cloned into pGEM Easy-T vector (Promega, Madison, Wis.) by standard methods. Stage Specificity: The stage-specificity of mtp-1 transcription was determined by RT-PCR (Hawdon et al, 1995). A. caninum eggs were isolated from the feces of infected dogs by sucrose floatation (Nolan et al., 1994), axenized by treatment with NaOCl, and plated on nematode growth medium agar plates (Sulston et al. 1988). Following incubation at 26 C for 24-30 h, the hatchlings (mixed L1/L2) were washed from the plates with BU buffer (Hawdon and Schad, 1991) and snap-frozen in a dry ice/ethanol bath. Unhatched eggs were also snap frozen to make cDNA. A. caninum adults were collected from the small intestine of an infected dog at necropsy. RT-PCR was performed on A. caninum eggs, mixed L1/L2 serum-stimulated and non-stimulated L3 (see below), and adult A. caninum samples as follows. Samples were ground to a powder in a pre-chilled (liquid N2) mortar, and total RNA isolated using the TRIzol reagent (Life Technologies, Gaithersburg, Md.) according to the manufacturer's instructions. The RNA was treated with 10 U DNAse 1 (RNase free, Boehringer Mannheim, Indianapolis, Ind.) and re-extracted with TRIzol. Total egg RNA was isolated by mechanical disruption with glass beads in the presence of TRIzol using a BeadBeater machine (BioSpec, Bartlesville, Okla.), DNAse treated, and re-extracted as above. First strand cDNA was synthesized from each sample in a 50 μL reaction containing 50 mM Tris HCl, pH 8.3, 75 mM KCl, 3 mM MgCl2, 10 mM DTT, 500 ng oligo(dT) primer, 1 μg of total RNA, and 200 U of Moloney murine leukemia virus reverse transcriptase (Life Technologies) at 37 C for 1 hr. The reaction was incubated at 94° C. for 5 min, and brought to 100 μL with dH2O. One μL of the first strand cDNA was used in a PCR with primers MTP5′-I(5′-CTTCTCATGATCAACAAACACTACG) SEQ ID NO: 65 and MTP3′-1 (5′AATCTAACTCCAACATCTTCTGGTG) SEQ ID NO: 66. The reaction was cycled 30 times for 1 min at 94 C, 1 min at 55 C, and 1 min at 72 C. Amplicons were separated by agarose gel electrophoresis and visualized by staining with ethidium bromide. Expression and Purification of Recombinant Protein: The full-length Ac-mtp-1 cDNA was cloned in-frame in the expression vector pET28 (Novagen) and transformed into competent BL-21 E. coli cells using standard techniques. Expression of the recombinant protein, containing 6 vector-encoded histidine residues (His-Tag) at the 5′ end, was induced by the addition of 1 mM IPTG for 3 hours at 37° C. One ml of cells expressing rMTP-1 were sedimented by centrifugation at 5000×g for 5 min, the supernatant discarded, and the cells lysed in 100 mls of TE (pH 8.0) containing 100 μg/ml lysozyme and 0.1% Triton X-100. After incubation at 30° C. for 20 min, the sample was sonicated (power level 2-3, 20-30% duty cycle) on ice for 10 bursts of 5 sec each until the sample was no longer viscous. Soluble and insoluble cell fractions were separated by electrophoresis in a 12% SDS-PAGE under reducing conditions, and the resolved proteins visualized with Cooomassie blue staining. For purification of rMTP-1, a cell pellet from 2 l of induced bacterial culture was suspended in 60 ml of 1.0% SDS, 0.5% 2-mercaptoethanol, boiled for 5 min, and cooled to room temperature. The extract was dialyzed against 2 liters of 0.1% SDS in PBS for 48 hr with 2 changes of buffer, and applied to a 10 ml HisBind nickel resin column (Novagen). Chromatography was conducted according to the manufacturer's instruction except that 0.1% SDS was added to all buffers. In an effort to increase solubility and investigate the domain structure of MTP-1, 3 constructs lacking the amino HisTag sequences were made by PCR. The full length Ac-MTP cDNA (1-1642 bp), the cDNA without the 5′-propeptide (408-1642 bp), and the putative catalytic domain (408-1101 bp) were cloned in frame into pET28 at the upstream NcoI site, thereby removing the HisTag coding sequence from the vector. The recombinant proteins were expressed under the same conditions as described above. Antiserum Production Anti-rMTP polyclonal antiserum. was obtained by immunizing BABL/C mice with purified rMTP. Twenty μg of column purified rMTP was co-precipitated with alum (Ghosh et al. 1996) and injected subcutaneously. Additional boosts with alum precipitated rMTP (20 μg each) were administered at 3, 6, and 9 weeks. Mouse antiserum was adsorbed against bacterial lysates of E. coli strain BL21 to remove antibodies reacting with bacterial proteins. Twenty-five ml of induced cells were centrifuged, dissolved in 25 mls of 2× sample buffer (100 mM Tris, pH6.8, 2% SDS, 2.5% 2-mercaptoethanol), and centrifuged at 12,000×g for 10 min. Nitrocellulose membranes (4 cm×8 cm) were soaked in the supernatant for 20 min, followed by incubation in transfer buffer (48 mM Tris, 39 mM glyine, 0.037% SDS, 20% methanol) for 30 min. The membranes were washed 3 times in PBS containing 0.1% Tween-20 and incubated with a 1:100 dilution of the mouse antiserum for 1 hr at 22 C. The incubation was repeated 2 times with fresh membranes. To confirm specificity of the antibody, an aliquot of the adsorbed mouse antiserum was adsorbed a second time against bacterial lysates of BL21 (DE3) cells expressing full length rMTP-1. The adsorbed antiserum was used for Western blotting. In vitro activation of L3 and collection of ES products: A. caninum L3 were activated under host-like conditions as described previously (Hawdon et al, 1999). Briefly, L3 collected from coprocultures were decontaminated with 1% HCIlin BU buffer (Hawdon and Schad, 1991) for 30 min at 22 C. Approximately 5000 L3 were incubated at 37 C, 5% CO2 for 24 hr in 0.5 ml RPM1640, tissue culture medium supplemented with 25 mM HEPES pH 7.0, and antibiotics (Hawdon et al., 1999) in individual wells of 24-well tissue culture plates. L3 were activated to resume feeding by including 15% (v/v) of a<10 kD ultrafiltrate of canine serum and 25 mM S-methyl-glutathione (Hawdon et al, 1995). Non-activated L3 were incubated in RPMI without the stimuli. The percentage of feeding larvae was determined as described (Hawdon et al, 1996). Medium containing activated and non-activated L3 were transferred to separate microcentrifuge tubes and centrifuged for 5 min at 14,000 rpm. Supernatants from identical treatment groups were pooled, filtered through a 0.45 μm syringe filter to remove any L3 and cast cuticles, and stored at −20 C. Prior to electrophoresis, the supernatants were concentrated by ultrafiltration using Centricon 10 cartridges (Amicon, Beverley, Mass.). Concentrated ES were washed with 1 ml of BU, ultrafiltered, and lyophilized. To collect adult ES, 1260 adult worms were incubated in RPM1640, tissue culture medium (Hawdon et al., 1999) for 15 hrs at 37 C, 10% CO2. The supernatant was concentrated 3-fold by ultrafiltration in Centricon 3 spin columns. Western blotting: Lysates of bacterial cells expressing rMTP-1 fusion proteins and lyophilized ES products were re-suspended in 2×SDS-PAGE sample buffer (4% SDS, 5% 2-mercaptoethanol, 15% glycerol) and separated on a 4-20% gradient SDS-PAG (Invitrogen, Carlsbad, Calif.). Separated proteins were transferred to a polyvinylidene fluoride membrane (Millipore, Bedford, Mass.) by electroblotting at 25V for 1 hr (Towbin et al., 1979). The membrane was blocked with 5% non-fat dry milk in wash buffer (PBS, pH7.4, 0.1% Tween 20) for 1 hour at 22 C. The blocked membrane was incubated for 1 hr at 22 C with a 1:5000 dilution of mouse rMTP antisermn which has been preabsorbed against bacterial lysates expressing full length rMTP. The membrane was washed 3 times with wash buffer for 10 min at 24° C., followed by incubation with a 1:5000 dilution of horseradish peroxidase-conjugated goat anti-mouse Ig (Boehringer Mannheim, Indianapolis, 1N) for 1 hour at 22° C. Bands were visualized using chemiluminescent detecting reagents (ECL+, Amersham. Pharmacia Biotech, Piscataway, N.J.). Results for Example 3A. Cloning of A. caninum MTP cDNA An A. caninum L3 cDNA expression library was screened using pooled sera with high anti-hookworm L3 titer collected from human patients in endemic regions of China. Twelve positive clones were identified, 6 of which were identical as determined by DNA sequencing. Each clone contained a 3′poly-A tail, but was truncated at the 5′ end. The 5′ end was isolated from A. caninum L3 cDNA by PCR using a primer derived from the nematode spliced leader (Hawdon et al., 1995; Bektech et al., 1988) together with the gene-specific primers P1. The full length cDNA, without the poly(dA) tail, is 1703 bp (see FIG. 8A, SEQ ID NO: 15) and encodes a 547 amino acid open reading frame (see FIG. 8B, SEQ ID NO: 16) with a calculated molecular weight of 61,730 and a pI of 8.72. The ATG start codon begins 2 nt downstream from the end of the spliced leader sequence, resulting in a total of 23 untranslated nt at the 5′ end of the Ac-mtp-1 cDNA. A TAA stop codon is located at nt 1666-1668, followed by a 35 bp 3′ UTR containing an AATAAA polyadenylation signal (Blumenthal and Steward, 1997) 12 bp upstream (bases 1687-1692) from the poly(da) tail. Amino acids 1 through 16 of the deduced protein sequence are predicted to represent a hydrophobic signal peptide, with a potential cleavage site between Ala,6 and Gly,7 (Nielson et al, 1995). The deduced sequence contains 2 potential N-linked glycosylation sites (N—X—S/T) at Asn39 and Asn159. A BLAST search (Altschul et al., 1997) of GenBank using the Ac-MTP-1 predicted amino acid sequence indicated significant homology to members of a family of zinc metalloproteinases called the astacins (Bond and Benyon, 1995), named for the digestive protease astacin from the crayfish Astacus astacus. A search of the protein structure databases (Apweiler et al, 2000) with the Ac-MTP-1 deduced amino acid sequence revealed the presence of characteristic astacin fingerprints, including the extended zinc binding domain and a conserved Met turn located 37 amino acids downstream. The catalytic domain containing the zinc binding site is followed by a domain with homology to epidermal growth factor (EGF), from amino acids 334 to 368. From amino acids 374 to 484 is a domain with weak homology to the CUB domain, named for its occurrence in complement subcomponents Cl r/C Is, embryonic sea urchin protein Uegf, and BMP-1. The EGF and CUB domains are common in astacin metalloproteinases, and are believed to be involved in protein-protein interactions (Bond and Benyon, 1995). Following the N-terminal signal peptide is a 119 amino acid, helix-rich pro-peptide domain. The C-terminal end of the propeptide domain contains a 4 basic amino acid sequence (R-E-K-R) from amino acids 132 to 135 that is a potential recognition site for furin or other trypsin-like processing enzymes (Bond and Benyon, 1995). Proteolysis at this site would activate Ac-MTP-I to a putative 412 amino acid processed form with a calculated MW of 46419 and a pI of 8.04. RT-PCR analysis of stage specificity: The stage-specificity of Ac-mtp-1 expression was investigated by qualitative RT-PCR of cDNA from several developmental stages of A. caninum. Ac-mtp-1 specific primers were designed to amplify a 434 bp portion of the Ac-mtp-1 cDNA corresponding to nt 985-1419 of the complete sequence. The product of the predicted size was amplified from both non-activated and activated L3 cDNA, but not from A. caninum egg or L1/L2 mixed stage cDNA. A band of lesser intensity was seen in adult cDNA. A longer fragment was amplified from genomic DNA, indicating that the primers spanned an intron, and confirming that the amplicons from the cDNAs were derived from amplification of cDNA rather than contaminating genomic DNA. Control primers that amplify a portion of the constitutively expressed A. caninum protein kinase A catalytic subunit (Hawdon et al., 1995) successfully amplified product from all DNA samples, indicating that amplifiable template was present. Expression of recombinant MTP and immunoblotting: Recombinant MTP-1 was produced in E. coli, purified by Ni column chromatography, and used to immunize BALB/c mice for the production of specific antiserum. The antiserum was adsorbed against E. coli lysates and used to determine if Ac-MTP-1 is secreted by A. caninum L3 in vitro. ES products from 10,000 non-activated (non-feeding) and activated (feeding) L3 were analyzed by Western blotting using the rMTP-1 antiserum. The antiserum recognizes both the full length and processed (i.e. without the pro-peptide domain) forms of rMTP-1 expressed in E. coli BL21 (DE3) cells but fails to recognize any bands in lysates of induced cells containing the vector alone. The rMTP antiserum recognized bands of MW, of 47.5 and 44.5 in the ES products of 10,000 A. caninum L3 that had been activated to resume feeding in vitro. The antiserum failed to recognize any bands in ES from 10,000 non-activated L3 in culture medium alone, or in adult A. caninum ES products or worm lysates (not shown). A slower migrating band in activated ES has a MW similar to that of the processed form of rMTP (47.5 versus 46.5), indicating that A. caninum L3 release processed MTP-1 during in vitro activation. The lower MW band was also recognized by pre-immune mouse serum (not shown), suggesting that the antiserum recognized a protein unrelated to Ac-MTP-1. To confirm that this recognition was non-specific, the mouse antiserum was adsorbed against BL21 (DE3) cells expressing full length MTP-1 and used to probe the Western blot. Adsorbed antiserum failed to recognize any rMTP-1, but recognized a band of MWr=44.5 in activated ES products, suggesting that recognition of the lower MW band by the antiserum is non-specific. Recombinant MTP-1 was recognized by the pooled sera used to screen the library, but sera from individuals living in a non-endemic area (Shanghai) failed to recognize rMTP-1 (not shown). Example 3B Isolation and Characterization of a MTP-1 cDNA Serum from hookworm-infected patients in China was used as a probe to carry out the isolation and characterization of a cDNA from an A. caninum L3 expression library that encodes a zincmetalloprotease (Ac-mtp-1) of the astacin family. An A. caninum (Baltimore strain) L3 cDNA expression library constructed in 1 ZapII (Stratagene, La Jolla, Calif.) (Hawdon et al., 1995) was screened according to the manufacturer's instructions using pooled antisera from patients in Anhui Province, China, where A. duodenale is the predominant hookworm species (Yong et al., 1999). Sera from patients with low fecal egg counts and high titers of circulating antibodies to A. caninum L3 whole lysate antigens, suggesting that they might be resistant to hookworm infection, were used. Six identical, truncated clones were recovered following plaque purification. The 5′ end was isolated from A. caninum L3 cDNA by nested PCR using the nematode spliced leader sequence together with two gene-specific primers (Hawdon et al., 1995), and two independent 5′ end clones were sequenced. Results from Example 3B. The amplified sequence is believed to represent the complete 5′ end of the transcript because the predicted ATG start codon is the first methionine following the spliced leader, the first 16 deduced amino acids encode a signal peptide characteristic of secreted proteins (Nielson et al., 1997), and alignments with similar metalloproteases suggest that this is the complete amino acid sequence. The full length cDNA, without the poly(dA) tail, is 1703 bp and encodes a 547 amino acid open reading frame with a calculated molecular weight of 61,730 and a pI of 8.72. Amino acids 1 through 16 of the deduced protein sequence are predicted to represent a hydrophobic signal peptide, with a potential cleavage site between Ala16 and Gly17 (Nielson et al., 1997). The protein sequence contains two potential N-linked glycosylation sites (NX-S/T) at Asn39 and Asn159. A BLAST search (Altschul et al., 1997) of GenBank using the Ac-MTP-1 predicted amino acid sequence indicated significant homology to members of a family of zinc metalloproteinases called the astacins (Bond and Beynon, 1995), named for a digestive protease from the crayfish Astacus astacus. Members of this family are characterized by a short-terminal signal peptide that targets them for secretion, followed by a pro-peptide, and a catalytic domain containing the characteristic zinc-binding region and ‘Met turn’. Unlike astacin, most other members of the family contain C-terminal domains, including variable numbers of EGF and CUB domains (Bond and Beynon, 1995). A search of the protein structure databases (Apweiler et al, 2000) with the Ac-MTP-1 deduced amino acid sequence revealed the presence of characteristic astacin fingerprints, including an extended zinc binding region, and a conserved Met turn located 37 amino acids downstream. The catalytic domain containing the zinc binding site is followed by a domain with homology to epidermal growth factor (EGF), from amino acids 334 to 368. From amino acids 374 to 484 is a domain with weak homology to the CUB domain, named for its occurrence in complement subcomponents Clr/Cls, embryonic sea urchin protein Uegf, and BMP-I (Bork and Beckman, 1993). Astacin metalloproteinases are synthesized as inactive proenzymes. Removal of the pro-peptide by a processing enzyme activates the enzyme (Bond and Beynon, 1995). Ac-MTP-1 contains a 119 amino acid N-terminal domain with a predicted four amino acid recognition site (R132 E133 K134 R135) for a trypsin- or furin-type processing enzyme at its C-terminus (Bond and Beynon, 1995). Proteolysis at this site would activate Ac-MTP-1 to a putative 412 amino acid processed form with a calculated MW of 46,419 and a pI of 8.04. The pro-peptide is also predicted to contain four amphipathic α-helices separated by a short linker region (amino acids 23-86) (Kelley et al., 2000). The stage-specificity of Ac-mtp-1 expression was investigated by qualitative RT-PCR of cDNA from several developmental stages of A. caninum. Specific primers were designed to amplify a 434 bp portion of the Ac-mtp-1 cDNA corresponding to nucleotides 985-1419 of the complete sequence. A product of the predicted size was amplified from both non-activated and activated L3 cDNA, but not from A. caninum egg or L1/L2 mixed stage cDNA, indicating that Ac-mtp-1 is expressed primarily in the L3 stage. A band of lesser intensity was seen in adult cDNA. Although this band was weak, conclusions regarding the amount of gene expression are not possible, as the RT-PCR is qualitative only. However, a Western blot of adult lysates using mouse anti-rMTP serum failed to recognize any proteins in adult ES or lysates (not shown). This suggests that expression of Ac-MTP-1 is restricted to the L3 stage, and that the message present in the adult stages is untranslated or possibly partially degraded. Recombinant MTP-1 was produced in Escherichia coli, purified by Ni column chromatography, and used to immunize BALB/c mice for the production of specific antiserum. The antiserum was adsorbed against E. coli lysates and used to determine if Ac-MTP-1 is secreted by A. caninum L3 in vitro. ES products collected from 10,000 non-activated (non-feeding) and activated (feeding) L3 (Hawdon and Schad, 1993) were analyzed by Western blotting using the rMTP-1 antiserum. The antiserum recognizes both the full length and processed (i.e. without the pro-peptide domain) forms of rMTP-1 expressed in E. coli BL21 (DE3) cells, but fails to recognize any bands in lysates of induced cells containing the vector alone. A lower MW band was observed and is similar in size to the processed rMTP (i.e. lacking the pro-sequence), suggesting that some of the rMTP expressed in E. coli undergoes in vitro cleavage at the C-terminal end of the pro-peptide. This is probably the result of autocatalytic cleavage, although non-specific cleavage by a bacterial protease is also a possibility. Autocatalysis might also represent the physiological activation mechanism of Ac-MTP-1 in vivo. The rMTP antiserum recognized bands of Mr of 47.5 and 44.5 in the ES products of 10,000 A. caninum L3 that had been activated to resume feeding in vitro. The antiserum failed to recognize any specific bands in ES from non-activated L3, in culture medium alone, or in adult A. caninum ES products or worm lysates (not shown). A slower migrating band in activated ES had a Mr similar to that of the processed form of rMTP (47.5 vs. 46.5), indicating that A. caninum L3 release processed MTP-1 during in vitro activation. Furthermore, MTP-1 is released only in response to stimuli that activate L3 to resume feeding, and therefore, most likely functions at some stage of the infective process (Hawdon et al., 1996). The metalloproteolytic activity described previously was also released specifically during activation, and was of similar molecular size (Hawdon et al., 1995), suggesting that Ac-MTP-1 might be responsible for at least a portion of this activity. A lower MW band (Mr 44.5 kDa) in activated ES products was also recognized by pre-immune mouse serum (not shown), suggesting that the antiserum recognized a protein unrelated to Ac-MTP-1. To confirm that this recognition was non-specific, the mouse antiserum was adsorbed against E. coli cells expressing full length MTP-1 and used to probe the Western blot. Adsorbed antiserum failed to recognize any rMTP-1, but recognized a band of Mr 44.5 in activated ES products, suggesting that recognition of the lower MW band by the antiserum is non-specific. Recombinant MTP-1 was recognized by the pooled sera used to screen the library, but sera from individuals living in a non-endemic area (Shanghai) failed to recognize rMTP-1 (not shown). While the exact function of Ac-MTP-1 is unknown, the stage specificity of expression and the specific release during activation suggest a critical role in the infective process. Thus, interruption of Ac-MTP-1 function in vivo offers a useful strategy for the development of a vaccine to control hookworm disease. This example demonstrates that MTP-1 is an important enzyme used by the hookworm parasite for invasion, and the protein is an immunodominant antigen because it is recognized by serum from patients with low hookworm burden despite repeated exposure to hookworm. MTP is therefore an attractive candidate for a vaccine antigen. Example 3C Canine Vaccine Trials with Ac-MTP-1 Antigen To test whether Ac-MTP-1 could be an effective vaccine, two groups of five (5) purpose-bred male beagles 8+1 wk of age were vaccinated either with the recombinant (expressed and isolated from Escherichia coli) fusion protein formulated with AS02A adjuvant, or adjuvant alone. The composition of AS02A, which has been successfully used in several malaria vaccine clinical studies, is described elsewhere (Lalvani et al, 1999; Bojang et al, 2001; Kester et al, 2001). Details of the animal husbandry and housing conditions were reported previously (Hotez et al, 2002a). The recombinant fusion protein containing a polyhistidine tag was purified from washed E. coli inclusion bodies that were solubilized in 6 M guanidine-HCl in 10 mM Tris HCl, pH 8.0. The solubilized inclusion bodies were processed in 5-10 ml batches by gel filtration chromatography (Sephacryl S-300, 26/60 gel filtration column [Amersham Pharmacia] pre-equilibrated in a buffer containing 0.1 NaH2PO4, 10 mM Tris-HCl and 6 M guanidine) at room temperature (flow rate of 2 ml/minute). Selected fractions containing Ac-MTP-1 (as determined by analysis on sodium dodecyl sulfate-polyacrylamide gel electrophoresis [SDS-PAGE]) were pooled, refolded according to the method of Singh et al (2001), and then loaded onto a 5 ml Hi-Trap IMAC column (Amersham Pharmacia) charged with ZnCl2 and equilibrated in 50 mM sodium phosphate pH 7.2, μM urea, and 0.5 M NaCl. The column was subsequently washed with 15 column volumes of equilibration buffer, and the bound protein was eluted with 50 mM sodium phosphate pH7.2, μM urea, 0.5 M NaCl, and 50 mM ethylenediamine tetraacetic acid (EDTA). Eluted samples containing protein were pooled and dialyzed against 10 mM Tris-HCl pH 8.0, 5% glycerol, 1 mM dithiothreitol, and 2 mM EDTA. The purified recombinant Ac-MTP-1 did not exhibit enzymatic activity (data not shown). The recombinant Ac-MTP-1 fusion protein was mixed with SBAS2 adjuvant and administered to each of five dogs in four intramuscular injections on days 1, 4, 43, and 50. Each dog received approximately 140 μg of recombinant fusion protein and 0.5 ml of AS02A per dose. Five dogs were also injected intramuscularly with AS02A on the same schedule. Following immunization, blood was collected weekly by venipuncture and the serum was separated and stored frozen at −20° C. Antigen-specific canine IgG2 and IgE antibodies were measured by indirect enzyme-linked immunosorbent assay (ELISA) as described previously (Hotez et al, 2002a). Immunoblotting of secretory products from nonactivated L3 and L3 activated under host stimulatory conditions was done as described previously (Zhan et al, 2002) using pooled sera from the Ac-MTP-1-vaccinated dogs. Fourteen days following the final immunization, each dog in the study was subcutaneosly infected with 500 A. caninum L3. The origin of the hookworm strain used for the study is described elsewhere (Hotez et al., 2002c). Validation of the hookworm species used in the study was confirmed by a polymerase chain reaction followed by restriction fragment length polymorphism (Hawdon, 1996). Following infection, the dogs were bled weekly by venipuncture to obtain a complete blood count (CBC). Serum chemistries were also obtained at the end of the vaccination schedule and prior to necropsy. Quantitative hookworm egg counts (McMaster technique) on each dog were obtained 3 days per wk beginning on day 12 post-infection (PI). Five wk post-infection, the dogs were killed by intravenous barbituate injection, and the adult hookworms were recovered and counted from the small and large intestines at necropsy (Hotez et al., 2002c). The statistical significance of differences between adult hookworm burdens was determined using the Anova test, as were differences in hematological parameters and in quantitative hookworm egg counts. Comparisons of hookworm burden and egg counts with antibody titers were measured using Spearman rank order (nonparametric) correlations. SDS-PAGE analysis of the Ac-MTP-1 recombinant fusion proteins followed by Coomassie blue staining revealed that the protein migrates with an apparent MW of 61 kDa—the predicted mass of the proenzyme. Also present is a triplet of bands that migrate with a lower apparent molecular weight, which probably corresponds to the partially processed Ac-MTP-1. Following immunization, each of the vaccine-recipient dogs developed high titers of IgG2 anti-Ac-MTP-1-specific antibody ranging between 1:40,500 and 1:364,500; the anti-Ac-MTP-1-specific IgE antibody responses ranged between 1:500 and 1:1,500. Sera from the vaccinated dogs recognized a triplet of closely migrating proteins with the predicted molecular weight of the proenzyme and processed form of Ac-MTP-1 in secretory products of host-activated L3, but not in those of non-activated L3. The additional bands may also correspond to other related metalloproteases secreted by A. caninum L3; at least 3 closely related expressed sequence tags from A. caninum L3 were found in a dbEST database (ncbi.nim.nih.gov/dbEST/index.html). Overall, there were no statistically significant differences in the number (mean+standard deviation) of adult hookworms recovered from the vaccinated dogs (154+34 hookworms) compared to the number of adult hookworms recovered from control dogs (143+hookworms). However, as shown in FIG. 33A there was a statistically significant reduction in the number of adult hookworms recovered from the intestines of vaccinated dogs that had high anti-A. caninum IgG2 antibody titers. The Spearman correlation between antibody titers and adult hookworm burden was −0.89 (P=0.04). The number of hookworms recovered from the dog with the highest antibody titer (98 hookworms) was equivalent to a 50 percent reduction in worm burden compared to the number of adult hookworms recovered from the dog with the lowest antibody titer (189 hookworms). An identical relationship was noted between IgG2 antibody titers and median quantitative egg counts (FIG. 33B). These studies suggest that Ac-MTP-1 might offer downstream promise as an anti-hookworm vaccine antigen. Example 4 Canine Vaccine Trials with Ac-TMP, Ac-AP, and Ac-APR-1 Antigens To evaluate whether antibodies directed against parasite enzymes and enzyme inhibitors have therapeutic potential for ancylostomiasis, canine vaccine trials employing recombinant fusion proteins that encode adult A. caninum proteases or protease inhibitors were conducted. Because small quantities of proteins are available from living hookworms, testing these molecules as vaccine candidates requires recombinant vector expression in prokaryotic or eukaryotic host systems, followed by canine immunization with the purified recombinant fusion protein. Material and Methods for Example 4. Study dogs and animal husbandry: Following protocol approval by The George Washington University Institutional Animal Care and Use Committee (IACUC), purpose bred, parasite naïve, male beagles 8+1 week of age were purchased, identified by ear tattoo, and maintained in the AALAC (Association for Assessment and Accreditation of Laboratory Animal Care) accredited George Washington University Animal Research Facility. The dogs were housed in a room dedicated for the study, at a room temperature of 70±4° F., with 10-15 air changes per hour comprised of 100 percent fresh air, and 12 hr light cycles alternating with 12 hr dark cycles. The airflow and timer functions were monitored daily. The dogs were fed on a diet of Teklad Certified Dog Chow #8727, supplemented with a canned soft diet in the event of anorexia. The drinking water was piped from a filter plant and delivered via automatc water system; water analysis was performed by the U.S. Army Corps of Engineers. Water from the facilities automatic system is cultured for bacteria and fungi annually. The pens were flushed daily and sanitized every two weeks. Dogs within a given study group were permitted to live together and socialize prior to the hookworm larval challenge, but were caged individually post-infection. All dogs were quarantined for approximately one week before beginning the vaccine trial. Prior to vaccination a complete blood count (CBC), serum chemistries, and a pre-vaccination serum sample were obtained. Vaccine study design and sample size: The vaccine trial was designed to test three different antigens, each formulated with alum, as well as an alum adjuvant control. A total of 24 dogs were randomly assigned into four groups comprised of 6 dogs each. The canine sample size was selected on the ability to detect a 40-50 percent reduction in the numbers of adult hookworms in the small intestines of the vaccinated group relative to control dogs, at a statistical power of 80 percent (alpha=0.05, two-tailed). The data were derived from the mean and standard deviation of adult hookworms previously recovered from age-matched dogs infected with 400 A. caninum L3 (Hotez et al, 2002). Recombinant Antigens: Each group of 6 dogs was vaccinated with recombinant hookworm proteins expressed as fusion proteins either in Escherichia coli or in an insect cell line with baculovirus. Ac-AP (Cappello et al, 1995; 1996) and Ac-TMP, were expressed in E. coli as pET 28 (Novagen) fusion proteins containing a polyhistidine tag (Cappello et al, 1996). Ac-APR-1 (Harrop et al, 1996) was expressed in a baculovirus pBacPAK6 vector (Clontech), modified to contain a polyhistidine-encoding sequence and additional restriction enzyme sites (Brindley et al, 2001). Recombinant Ac-AP and Ac-TMP fusion proteins were then purified by nickel affinity chromatography, followed by a second step of purification. In the case of Ac-AP (Cappello et al, 1995; 1996), the recombinant protein was purified by mono-S (Amersham-Pharmacia) ion exchange chromatography, while Ac-TMP (Zhan et al, 2002) was purified by superdex 75 (Amersham-Pharmacia) gel filtration chromatography. Ac-APR-1 (Harrop et al, 1996) was purified by substrate affinity chromatography using pepstatin agarose (Brindley et al, 2001). The antigen stock protein concentration was determined by Pierce Micro BCA assay (Pierce Chemicals) or by the absorbance of the sample at 289 nm using an extinction coefficient that was calculated from the deduced amino acid composition of the fusion protein. The amount of alum adsorbed protein in each dose of antigen was measured by the Pierce Micro BCA assay using a bovine serum albumin standard. The relative purity of each of the antigens relative to contaminating E. coli or insect cell proteins was determined by analysis on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Adjuvant formulations: Recombinant Ac-TMP and Ac-APR fusion proteins were alum precipitated with a combination of aluminum potassium sulfate dodecahydrate and sodium bicarbonate as described previously (Ghosh et al, 1996). The method requires the precipitation of an aqueous solution of the protein with aluminum salt under alkaline conditions, followed by centrifugation and washing (Ghosh and Hotez, 1999). Using this method, recombinant Ac-AP fusion protein was not detected in the alum precipitate. Therefore, the first two doses of Ac-AP were administered without adjuvant. However, the final two doses of Ac-AP were adsorbed to an amorphous, non-crystalline calcium phosphate gel. Canine Immunizations: A four-dose immunization schedule was selected (Table II). Each of the dogs was vaccinated by subcutaneous immunization at two sites in the shoulder, through a 22 gauge needle. The volume of the injections ranged between 0.5 and 1.0 ml. Four doses of each antigen were administered over a 38-day period. The first two injections (primary immunization) were administered on days 1 and 4, and the final two immunizations (boosts) were administered on days 34 and 38. Dogs in the control group were injected with an equivalent amount of alum. TABLE II Antigen quantities and adjuvants used for each canine vaccination. Ac-AP Ac-TMP Ac-APR-1 Alum Dose 1 (day 1) 100 μg 71 μg 12.5 μg — Adjuvant None Alum Alum Alum Dose 1 (day 1) 100 μg 71 μg 12.5 μg — Adjuvant None Alum Alum Alum Dose 1 (day 1) 180 μg 61 μg 95 μg — Adjuvant Calcium phosphate Alum Alum Alum Dose 1 (day 1) 273 μg 69 μg 86 μg — Adjuvant Calcium phosphate Alum Alum Alum Canine antibody measurements: Blood was collected weekly by venipuncture and the serum was separated and stored frozen at −20° C. Antigen-specific canine IgG1 antibodies were measured by indirect enzyme-linked immunosorbent assay (ELISA). Other IgG subclasses were not measured due to the unavailability of suitable high-quality canine-specific reagents. The optimal concentrations of sample sera and enzyme-linked detection antibody were determined by checkerboard titrations. Optimal antigen concentrations were determined by using a saturation technique. NUNC Maxisorp F96 certified plates (Rosklide, Denmark; Batch no. 045638) were coated with 0.1 ml per well of antigen in 0.05 M carbonate bicarbonate buffer (pH 9.6). Sealed plates were incubated overnight (ON) at 4 C and then washed 3 times with PBS (pH 7.2) using a DYNEX Opsys plate washer (Chantilly, Va.). The plates were treated for 1.5 hours with 0.25 ml per well of 0.15M PBS (pH 7.2) containing 0.5% Tween 20 (PBS-Tween 20) at room temperature (RT), decanted, and blotted on paper towels. Various serial dilutions of test sera were prepared in 0.1 ml PBS-Tween 20 and incubated ON at 4 C. After washing, 0.1 ml of anti-canine IgG1 conjugated to alkaline phosphatase (Bethyl Laboratories, Montgomery, Tex.) at a dilution of 1:1000 were added to each well. After 1.5 hours at RT, the plates were washed 10 times with PBS-Tween 20, before 0.1 ml of 2.5 mM of para-nitro phenylphosphate (Sigma St. Louis, Mo.) in a solution of 10 mM diethanolamine (Sigma, St. Louis, Mo.) and 0.5 mM magnesium chloride (Sigma, St. Louis, Mo.) (pH 9.5) were added to each well. The plates were incubated in the dark for 30 minutes and read at a wavelength of 405 nm on a SpectraMax 240 PC reader (Molecular Devices, Sunnyvale, Calif.) with SOFTmax Pro software (Molecular Devices, Sunnyvale, Calif.). The mean optical density of control canine sera was used as a baseline. The last serum dilution greater than 3 times above baseline was considered the titration endpoint. The geometric mean of these endpoints was calculated for the six canines from each group. Canine hookworm infections and parasite recovery: Fourteen days following the final immunization, each dog in the study was orally infected with 400 A. caninum L3 administered in a gelatin capsule. The origin of the hookworm strain used for the study is described elsewhere (Hotez et al, 2002). Validation of the hookworm species used in the study was confirmed by a polymerase chain reaction followed by restriction fragment length polymorphism (Hawdon, 1996). Following infection, the dogs were bled weekly by venipuncture in order to obtain a complete blood count (CBC). Serum chemistries were also obtained at the end of the vaccination schedule and prior to necropsy. Quantitative hookworm egg counts (McMaster technique) on each dog were obtained three days per week beginning on day 12 post-infection. Five weeks post-infection, the dogs were euthanized by intravenous barbituate injection, and the adult hookworms were recovered and counted from the small and large intestines at necropsy (Hotez et al, 2002). The sex of each of the adult hookworms was determined by visual inspection. The necropsies were performed over a period of three days when 8 dogs per day (two dogs from each of the four groups) were euthanized. Approximately 1-2 cm of small intestine was separated and placed into formalin for future histopathological analysis. Statistical methods: The percentage reduction or increase in adult hookworm burden in the vaccinated group was expressed relative to the control group by the following formula: ( mean hookworms in control group - mean hookworms in vaccinated group ) ( mean hookworms in control group ) × 100 The statistical significance of differences in adult hookworm burdens was determined using nonparametric tests; the Kruskal-Wallis with Dunn procedures, and Mann-Whitney U tests. Differences between groups in hematological parameters and in quantitative hookworm egg counts were assessed by the ANOVA test. When more than two tests were computed on the same variable, the level of significance was adjusted for the number of tests. The sex differences of the adult hookworms recovered were statistically compared by the Wilcoxon-Signed Ranks test for two dependent groups. Differences were considered statistically significant if the calculated P value was equal to or less than 0.10 (two sided) or −0.05 (one sided). Results for Example 4. Adult A. caninum antigens: Three recombinant A. caninum antigens were selected for canine vaccinations. Two of them, Ac-AP and Ac-TMP are protease inhibitors secreted only by adult stage hookworms. Ac-AP is a 91 amino acid factor Xa inhibitor anticoagulant (Cappello et al, 1995; 1996), and Ac-TMP is a 140 amino acid putative tissue inhibitor of metalloproteinase, and the most abundant protein secreted by A. caninum. The third antigen selected, was Ac-APR-1, a 422 amino acid aspartic acid cathepsin (Harrop et al, 1996). SDS-PAGE analysis of the recombinant fusion proteins followed by Coomassie blue staining was carried out. As expected, the recombinant fusion proteins Ac-APR-1 and Ac-TMP migrated on SDS-PAGE with apparent molecular weights of Mr=45,000 and 18,000, respectively. The predicted molecular mass of Ac-AP expressed as a pET 28 fusion protein with an N-terminal poyhistidine tag is 12,191 Da (Cappello, 1996). On SDS-PAGE, the recombinant Ac-AP fusion protein was visualized as a band with a predominant Mr of 22,000 and a minor band that migrates at approximately 15,000 Da. This observation may correspond to polypeptide oligomer formation. This was shown previously to occur during purification of the Ac-AP natural product (Cappello et al, 1995). Factor Xa inhibitory activity, DNA sequence analysis of the pET 28 plasmid encoding the recombinant Ac-AP fusion protein, and amino terminal peptide sequence analysis by Edman degradation of the 22 kDa band confirmed the identity of the gene product (data not shown). Canine antibody responses. A canine vaccination schedule was selected that provided for a primary immunization to be administered in two subcutaneous doses over an initial 4-day period (day 1 and day 4), followed by two subsequent subcutaneous immunization boosts that were administered beginning 30 days after the primary immunizations (day 34 and day 38). Ac-TMP and Ac-APR-1 were injected as alum-precipitated proteins. In contrast, Ac-AP did not form a precipitate with alum. Therefore, for the first two doses, Ac-AP was administered subcutaneously without adjuvant. However, during the 30-day time period between the second and third immunization, a protocol that employed calcium phosphate gel was shown to effectively precipitate Ac-AP (data not shown). For that reason, calcium phosphate was selected as the adjuvant for the final two immunizing doses of Ac-AP. Geometric mean IgG1 antibody titers to the three vaccine antigens are shown in FIG. 34A-C. Among the dogs vaccinated against Ac-APR-1 (FIG. 34A), there was a rise in antigen-specific IgG1 following the final two immunization boosts at approximately 6 weeks after the primary immunization. In contrast, anti-Ac-TMP IgG1 antibody responses were more robust (FIG. 34B), and began to increase 2 weeks following the primary immunization, prior to the third and fourth doses. Following the final two boosts there was a second increase in anti-Ac-TMP antibody titer that exceeded 1:10,000. Five of the six dogs vaccinated against Ac-AP failed to respond immunologically to the antigen. As shown in FIG. 34C, the single canine who responded to Ac-AP vaccination exhibited an antigen-specific antibody response following the final two doses. Adult A. caninum hookworm recovery from the small intestine. The numbers of adult A. caninum hookworms recovered from the small intestines of the vaccinated dogs is shown in Table III. Hookworm burden reductions in the vaccinated dogs relative to dogs injected with alum alone ranged between 4.5 to 18 percent. The above reduction was not sufficient to show statistical significance between groups (Kruskal-Wallis test, P=0.19). However, the probability (P) of 18 percent reduction in the number of hookworms recovered from the small intestines of the dogs vaccinated with Ac-APR-1 (the biggest reduction in one group) was less than 0.05 by the Dunn procedure, and 0.03 by Mann-Whitney U one sided test. Dogs vaccinated against Ac-TMP also exhibited a reduction in the adult hookworm burden (10.8 percent) although this was not statistically significant. The five dogs that did not exhibit an antibody response against Ac-AP, also exhibited no significant hookworm burden reduction. However, the single dog with a significant anti-Ac-AP antibody response, exhibited a 34.7 percent reduction in adult hookworm burden. As shown in Table III, data did not provide sufficient evidence for statistically significant reductions in quantitative hookworm egg counts between the vaccinated and control dogs. Similarly, vaccination did not affect the hematological parameters of the dogs, including hematocrit, hemoglobin, white blood cell count, and eosinophilia (data not shown). As expected, the challenge dose of hookworm used in this study did not produce anemia in the control alum-injected dogs (data not shown). Adult A. caninum hookworm recovery from the colon. TABLE III Reduction of adult hookworms in the small intestines of vaccinated relative to alum-injected dogs. Experimental Dogs WORMS % group No. Mean SD Median Decrease Control 6 176 22 180 Ac-AP 5 168 36 170 4.5 Ac-AP* 1 115 115 34.7 Ac-TMP 6 157 26 161 10.8 Ac-APR-1 6 144 31 138 18** *Positive immune response **P < 0.05 (Dunn procedure) Whereas there was a reduction in the numbers of adult hookworms recovered from the small intestines of vaccinated dogs, there was a corresponding increase in the number of adult hookworms that were recovered from the colon (Table IV). TABLE IV Increase of adult A caninum hookworms in the colons of vaccinated dogas relative to alum-injected dogs. Experimental Dogs WORMS % group No. Mean SD Median Increase Control 4 6 8 4 Ac-AP 5 17 17 14 183 Ac-AP* 1 71 71 1083 Ac-TMP 4 36 11 32 500** Ac-APR-1 5 24 11 27 300** *Positive immune response **P < 0.05 (Dunn procedure) The increase in the number of adult hookworms recovered from the large intestines was statistically significant (Kruskal-Wallis test, P=0.07). The dogs vaccinated with either Ac-TMP (500 percent increase) or Ac-APR-1 (300 percent increase), exhibited a statistically significant increase relative to the dogs injected with alum (Dunn procedure, P<0.05). Dogs that were vaccinated with Ac-AP but did not exhibit an antigen-specific antibody response did not have a statistically significant increase in the number of adult hookworms recovered from the colon. However, the single dog with a significant anti-Ac-AP antibody response exhibited a 1083 percentage increase in the number of adult hookworms in its colon. Overall, there were no statistically significant differences between the vaccinated and control dogs with respect to the total numbers of adult hookworms recovered from small and large intestines combined (data not shown). Instead, antibody responses to the recombinant hookworm antigens resulted in significant migration of adult hookworms away from the small intestine and into the colon. The ratio of adult hookworms in the small intestine relative to the colon decreased from 43.9 in the alum-injected dogs down to ratios between 6.6 and 7.3 in the Ac-TMP and Ac-APR-1 vaccinated dogs, respectively. The single dog exhibiting an anti-Ac-AP antibody response had a small intestine to colon hookworm burden ratio of 1.6, indicating that almost one-half of this dog's hookworm burden had shifted to the colon. Sex-dependent differences. Hookworms of either sex did not migrate away from the small intestine and into the colon in equal numbers. As shown in FIG. 35, it was more common to recover female adult hookworms from the colon than males. The greater numbers of female hookworms residing in the colon was statistically significant for dogs vaccinated with Ac-APR-1 (P=0.04) and Ac-AP (P=0.06). Male hookworms were more likely than female hookworms to be recovered from the small intestines, although the differences were not statistically significant. Sex determinations were not made on the hookworms attached to a 1-2 cm segment of small intestine that was saved for histopathological analysis. The mean number of hookworms in this segment ranged between 5 and 6 worms. This small number of worms did not contribute significantly to the sex-dependent difference score (data not shown). This example demonstrates that it is feasible to vaccinate mammals with recombinant fusion proteins to elicit an antigen specific response, and that the antibody response is associate either with a hookworm burden reduction in the gut or in a shift in hookworm habitat in the gut. Example 5 Canine Vaccine Trials of Ac-MTP-1 and Ac-TTR Example 5 A. Antibody Titers and Hookworm Reduction E. coli derived antigens Ac-MTP-1 and Ac-TTR were tested in vaccine trials in dogs. Antigens were administered with adjuvant SBAS2. The vaccinated animals exhibited high levels of canine IgG2 antigen-specific antibodies, and a modest increase in antigen-specific IgE. Subsequently the dogs were challenged by subcutaneous injection of L3 hookworm larvae. As shown in FIGS. 36A and B, there was a statistically significant reduction in the number of adult hookworms recovered from the intestines of vaccinated dogs that had high anti-A. caninum IgG2 anti-MTP-1 antibody titers. The Spearman correlation between antibody titers and adult hookworm burden was −0.89 (P=0.04). The number of hookworms recovered from the dog with the highest antibody titer (98 hookworms) was equivalent to a 50 percent reduction in worm burden compared to the number of adult hookworms recovered from the dog with the lowest antibody titer (189 hookworms). An identical relationship was noted between IgG2 antibody titers and median quantitative egg counts. SDS-PAGE analysis of the Ac-MTP-1 recombinant fusion proteins followed by Coomassie blue staining revealed that the protein migrates with an apparent MW of 61 kDa—the predicted mass of the proenzyme. Also present is a triplet of bands that migrate with a lower apparent molecular weight, which probably corresponds to the partially processed Ac-MTP-1. Following immunization, each of the vaccine-recipient dogs developed high titers of IgG2 anti-Ac-MTP-1-specific antibody ranging between 1:40,500 and 1:364,500; the anti-Ac-MTP-1-specific IgE antibody responses ranged between 1:500 and 1:1,500. Sera from the vaccinated dogs recognized a triplet of closely migrating proteins with the predicted molecular weight of the proenzyme and processed form of Ac-MTP-1 in secretory products of host-activated L3, but not in those of non-activated L3. With respect to the use of the TTR antigen, as can be seen in FIGS. 37A and B, one dog with high IgE and IgG1 antibody to TTR exhibited reduced (6%) hookworm burden. This example demonstrates that vaccination of mammals with either MTP or with TTR elicit a protective antibody response, and that with high antibody titers a reduction in worm burden is observed. Example 5B Protection Against Blood Loss and Decrease in Hookworm Size Due to Vaccination with Hookworm Antigen Animals were also tested to ascertain whether vaccination with hookworm antigens protected against blood loss. Vaccination with Ac-TTR was shown to confer significant protection against blood loss (FIGS. 38A and B). Using the Mann-Whitney test, the differences in both hemoglobin (38B) concentration (P=0.036) and hematicrit (38A) concentration (P=0.009) between the TTR and adjuvant control groups were statistically significant. Further, the differences in hemoglobin concentration translated to a statistically significant reduction in worm size. Data was collected using an imaging system based on scans of the worms recovered from a host. Worms were photographed with a CoolSnapPro digital camera (Media Cybernetics), and the images measured in ImagePro Software using a macro to determine worm length (in mm) compared between treatments. As shown in FIG. 39 there was a statistically significant reduction in worm size (between 1 and 2 mm) among the TTR vaccinated group relative to the adjuvant control group. This example demonstrates that vaccination with TTR, in addition to reducing worm burden, will also reduce blood loss. Example 6 Chimeric Hookworm Antigens The protective effect of two different hepatitis B core particles expressing a peptide epitope that corresponds to amino acids 291-303 of Na-ASP-1 (also found in Ac-ASP-1) were investigated. Previously by investigation of relative hydropathy (hydrophobicity and hydrophilicity) of the predicted amino acid sequence of Na-ASP-1 and Ac-ASP-1 it was discovered that both molecules exhibit a hydrophilic sequence that modeling predicted could represent a looped-out region of the molecule. Covalent attachment of the peptide to KLH (keyhole limpet hemocyanin) confirmed that the chimeric molecule could protect mice against challenge infections. Two different chimeric molecules expressing ASP-1 were constructed. ICC-1546 expresses ASP-1 amino acids 291-303 as a “looped out” tethered structure, whereas ICC-1564 expresses the same peptide as an N-terminal structure. Previous studies had demonstrated that mouse anti-L3 antibody recognizes ICC-1546, but not ICC-1564. The antigenic chimeras were administered as described above with alhydrogel as adjuvant. DSM (detergent solubilized membrane extract of adult A. caninum) served as a negative control. Larval challenge was carried out by subcutaneous injection of L3 stage larvae. The results showed that vaccination of dogs with either particle produced high levels of anti-particle antibody. Most of the antibody was directed against the hepatitis core antigen constituent. However, in one dog vaccinated with ICC-1546, there was a high level of anti-ASP-1 (and anti-peptide) antibody. This dog exhibited a significant reduction in hookworm burden (Table V). TABLE V Comparison of Anti-ASP-1 antibody and hookworm burden ICC 1546 Total Hookworms Anti-ASP-1 IgG1 IgG2 A1 139 1:800 0 A2 181 1:800 0 A3 170 1:200 0 A4 180 1:800 0 A5 118 1:1,600 1:1,600 Average A 158 ICC 1564 Total Hookworms Total Hookworms IgG2 B1 135 1:100 0 B2 143 1:100 0 B3 206 1;200 0 B4 195 1:800 0 B5 217 1:400 0 Average B 179 Alum Total Hookworms Total Hookworms Total Hookworms D1 176 0 0 D2 150 0 0 D3 161 0 0 D4 241 0 0 D5 255 0 0 Average D 191 This example demonstrates that high antibody titers to a specific epitope associated with ASP-1 will result in reduced worm burden. Example 7 Antigen Expression in Baculovirus/Insect Cells and Yeast Expression of hookworm antigens in eukaryotic expression systems, such as baculovirus/insect cells and the yeast Pichia pastoris, have been carried out to afford maximum opportunities for obtaining soluble and bioactive recombinant proteins. A. Expression in Pichia Pastoris The antigens Na-ASP-1, Ac-TTR, Ac-API, and Ay-ASP-2 have been successfully expressed with Pichia fermentation systems. Antigens were isolated with polyhistidine tags for ease of isolation. B. Expression in Baculovirus/Insect Cell System Antigens Na-CTL, Ac-MEP-1, Ac-ASP-2 and Ac-MTP-1 have been successfully expressed in a baculovirus/insect cell expression system. Antigens were isolated with polyhistidine tags for ease of isolation. Example 8 Cloning of cDNAs of A. Ceylanicum Orthologous Antigens Ay-ASP-1, Ay-ASP-2 and Ay-MTP Orthologous antigens from the hamster parasite hookworm A. ceylanicum were successfully cloned following the construction of an A. ceylanicum larval cDNA library. The A. ceylanicum orthologue of ASP-1 was cloned by screening the A. ceylanicum L3 cDNA library using a 900 bp 32P-labeled Ac-ASP1 cDNA fragment as a probe. Screening of approximately 500,000 clones resulted in 85 positive clones. Of these 21 clones were sequenced of which 19 encoded identical cDNAs. No other orthologues of ASP-1 were found. The clones exhibited 85% identity and 92% similarity with Na-ASP-1. By screening approximately 100,000 plaques of the A. ceylanicum L3 cDNA library using a 600 bp 32P-labeled Ac-asp-2 cDNA fragment as a probe, 30 positive clones were obtained, of which 10 were sequenced and found to be identical to Ay-ASP-2 predicted ORFs (orthologous clones). By screening approximately 500,000 A. ceylanicum L3 cDNA library using a 590 bp 32P-labeled Ac-MTP cDNA fragment as a probe, 700 positive clones were obtained and 8 sequenced. Seven of the 8 encoded Ay-MTP-1, while one other encoded a putative isoform (Ay-MTP-2). This example demonstrates that there is a high degree of similarity between antigens from A. caninum and A. ceylanicum hookworm species, and the data suggests a high degree of identity (>80%) amongst most of hookworm antigens. Example 9 Immunolocalization Immunolocalization of some of the major vaccine antigens was carried out in sections of adult hookworms. The immunolocalizations were determined to be as follows: Ac-103 as a hookworm surface antigen, Ac-FAR-1 and Ac-API as components of the pseudocoelomic fluid, (Ac-API is also a pharyngeal protein), Ac-CP-1 as an amphidial gland protein, Ac-TMP in the excretory glands, and ASP-3 as an amphidial and esophageal protein. In addition the total proteins of the hookworm ES products localized to amphidial and excretory glands, and to the brush border membrane of the hookworm alimentary canal. This example demonstrates that many of the hookworm antigens are exposed either on the surface of the worm or secreted by worm and are therefore susceptible to targeting by host antibodies or host immunocompetent cells. Example 10 Human Investigations Conducted in Minas Gerais State, Brazil It has been previously reported that in China and elsewhere, human hookworm infection exhibits a unique epidemiology compared with the other soil-transmitted helminthiases (e.g., ascariasis and trichuriasis) and schistosomiasis (Gandhi et al, 2001). Whereas the prevalence and intensity of these other helminth infections peak during childhood and adolescence and subsequently decline into adulthood, the prevalence and intensity of hookworm infection increases with age. In many Chinese and Brazilian villages (and presumably elsewhere) middle aged and even elderly residents exhibit the most severe infections. The underlying immunological mechanisms accounting for this observation has been investigated. Shown in FIGS. 40 and 41, CD-4+lymphocytes were gated from the whole blood of hookworm infected residents and stimulated with either L3 soluble hookworm antigen FIG. 40) or Pichia-expressed recombinant Na-ASP-1 (FIG. 41). Host cytokine production was measured by an intracellular cytokine staining technique. Both antigens stimulated high levels of IL-10 and IL-5, but not IL-4. IL-10 is a strong immunomodulator with downregulatory, anti-inflammatory properties, and IL-4 is associated with antibody production and TH-2 type immunity. The findings suggest that hookworm infected individuals might be anergic to hookworm and possibly other antigen stimulation. In contrast, it was shown that individuals treated for hookworm produce IL-4. This observation indicates that removal of hookworms from the intestine helps to reconstitute a patient's immunity. This is a critical observation since it suggests that in the absence of treatment a recombinant hookworm vaccine may be unlikely to function as a therapeutic vaccine in patients who are actively infected, and that anthelminthic chemotherapeutic treatment may be necessary prior to vaccination. Further, these observations also suggest that hookworm infection might thwart otherwise successful vaccinations against such etiological agents as HIV and malaria. In regions of Subsaharan Africa where hookworm overlaps with HIV and malaria, it may become essential to monitor a study participant's hookworm status prior to HIV or malaria vaccination, and to treat those that are found to be actively infected prior to immunization. References Altschul S F, Madden T L, Schaeffer A A, Zhang J, et al. 1997. Gapped BLAST and PSI-BLAST: a new generation of protein database search programs. Nucl Acids Res 25:3389-402. Apweiler R, Attwood T K, Bairoch A, Bateman A, et al. 2000. 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Slaoui, C. Van Hoecke, W. R. Ballou, A. V. Hill, J. Cohen. 1999. Potent induction of focused ThI-type cellular and humoral immune responses by RTS,S/SBAS2, a recombinant Plasmodium falciparum malaria vaccine. Lancet 180:1656-64. Nielsen H, Engelbrecht J, Brunak S, von Heijne G. 1997. Identification of prokaryotic and eukaryotic signal peptides and prediction of their cleavage sites. Protein Eng 10:1-6. Nolan T J, Bhopale V, Megyeri Z, Schad G A. Cryopreservation of human hookworms. J Parasitol 1994; 80: 648-50. Prociv P, Croese J. 1990. Human eosinophilic enteritis caused by dog hookworm Ancylostoma caninum. Lancet 335:1299-302. Sambrook J, Russel D W. Molecular Cloning, A laboratory Manual, third ed. Cold Spring Harbor, N.Y.: Cold Spring Harbor Laboratory Press, 2001. Savioli L, Bundy D, Albonico M, Renganathan E. 1997. Anthelmintic resistance in human helminths: learning from the problems with worm control in livestock* reply. Parasitol Today 13:156. Schad G. 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Cold Spring Harbor: Cold Spring Harbor Laboratory, 1988;587-606. Towbin H, Staehelin T, Gordon J. Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications. Proc Natl Acad Sci USA 1979; 76: 4350. Xue H C, Wang Y, Xiao SH, Liu S, et al. Epidemiology of human ancylostomiasis among rural villagers in Nanlin County (Zhongzhou Village), Anhui Province, China: 11. Seroepidemiological studies of the age relationships of serum antibody levels and infection status. Southeast Asian J Trop Med Public Health 2000; 3 1: in press. Yong W, Guangjin S, Weitu W, Shuhua X, et al. 1999. Epidemiology of human ancylostomiasis among rural villagers in Nanlin County (Zhongzhou village), Anhui Province, China: age-associated prevalence, intensity and hookworm species identification. Southeast Asian J Trop Med Public Health 30:692-7. Example 11 Cloning, Yeast Expression, Isolation and Vaccine Testing of Recombinant Ancylostoma-Secreted Protein (ASP)-1 and ASP-2 from Ancylstoma Ceylanicum An estimated 740 million people in the developing countries of the tropics and subtropics are infected with the hookworm Necator americanus or Ancylostoma duodenale [1]. The highest prevalence of hookworm infection occurs in impoverished rural areas of sub-Saharan Africa, Southeast Asia, China, Brazil, and Central America [1, 2]. In some of these regions, up to 57% of the moderate and severe iron deficiency anemia (IDA) is attributable to hookworm infection [3-5], which results from parasite-induced blood loss and hemoglobin digestion [6-8]. IDA accounts for huge numbers of disability-adjusted life-years lost in developing countries; some studies rank IDA among the top 15 causes of global disease burden [9, 10]. Because it is linked to a major etiology of IDA, hookworm infection is considered, in terms of DALYs, to be one of the most important parasitic diseases of humans, possibly second only to malaria [11]. At present, the major approach to hookworm control relies on frequent and periodic dewormings through the administration of albendazole and other anthelminthic drugs. There has been significant interest by the World Health Organization (WHO) and other international organizations in conducting such interventions on a large scale [12], particularly for school-aged children, who might otherwise suffer from the physical and intellectual growth retardation effects of hookworm and other soil-transmitted helminths (STHs) [13-15]. However, unlike other STH infections (e.g., ascariasis and trichuriasis), there is an emerging body of evidence suggesting that the peak prevalence and intensity of hookworm frequently occurs among adult populations [16-18], including high rates of hookworm infection among pregnant women, in whom hook-worm-induced IDA results in adverse consequences for both the mother and the unborn fetus [19]. Therefore, the school-based anthelminthic chemotherapy programs now being pro-posed by WHO and other international health agencies to control STH infections might fail to target hookworm. Moreover, hookworm reinfection often occurs within just a few months after anthelminthic treatment [20]. This feature of human hookworm infection would also thwart the success of mass chemotherapy initiatives. As an alternate or complementary approach to hookworm control, efforts are under way to develop a vaccine [11]. On the basis of previous success with trickle doses of third-stage infective hookworm larvae (L3) or L3 attenuated by ionizing radiation (irL3) [21], vaccine development efforts have targeted the major antigens secreted by hookworm L3 at entry into the host [22]. The most abundant antigens released by hookworm L3 by host stimulation with serum have now been cloned from the dog hookworm A. caninum, including a zinc metalloprotease of the astacin class [23] and 2 Ancylostoma-secreted proteins (ASP-1 and ASP-2) that belong to the pathogenesis-related protein (PRP) superfamily [22, 24-25]. To test whether these antigens protect laboratory animals against challenge infections, we have adopted a parallel strategy of testing them as immunogens in dogs challenged with A. caninum and in hamsters challenged with A. ceylanicum. Both systems offer unique advantages and disadvantages [11]. Here, we report the cloning and yeast expression of asp-1 and asp-2 cDNAs from A. ceylanicum, the isolation of the recombinant macromolecules, and their vaccine testing in hamsters. We report that vaccination of hamsters with recombinant ASP-2 formulated with the adjuvant Quil A results in protection, as evidenced by reduction in hookworm burden, hookworm size, and spleen size, compared with those in control hamsters vaccinated with Quil A alone. Materials and Methods for Example 11. Cloning of asp-1 and asp-2 cDNAs from A. Ceylanicum To construct an A. ceylaninum L3 cDNA library, L3 of A. ceylanicum were obtained from coprocultures of a donor dog infected with A. ceylanicum. Total RNA was exacted from A. ceylanicum L3 by use of the TRIzol reagent (GIBCO BRL), and mRNA was isolated by use of oligo dT affinity chromatography (Oligotex mRNA Mini Kit; Qiagen). A 1 ZAPII cDNA library was constructed according to the manufacturer's instructions (Stratagene). Products of the polymerase chain reaction (PCR) from A. caninum cDNA and asp-specific primers were used as heterologous probes to screen the A. ceylanicum library [24, 25]. The species derivation of each hookworm reagent was abbreviated as follows: Ac, A. caninum; Ad, A. duodenale; Ay, A. ceylanicum; and Na, N. americanus. Specific primers for Ac-asp-1 DNA (Ac-asp-1 F1: 5-GCTCTCCGGCTGGTGG-3 (SEQ ID NO: 78) and Ac-asp-1 R1: 5-TTAAGGAGCGCTGCACAAGCC-3 (SEQ ID NO: 79)) were used to amplify Ac-asp-I cDNA (366-1275 bp). Specific primers for A. caninum asp-2 DNA (Ac-asp-2 F 1: 5-GGGAATTCA-ATTCTATGAGATGCGGAAA-3 (SEQ ID NO: 80) and Ac-asp-2 R1: 5-TGTCT-AGATAGCCACGCACGACGCAAA G-3 (SEQ ID NO: 81)) were used to amplify Ac-asp-2 cDNA (66-668 bp). The first-strand A. caninum L3 cDNA reverse transcribed from A. caninum L3 total RNA was used as a template. The PCR products were labeled randomly with a 32 [P]-dCTP by use of a Rediprime labeling kit (Amersham). The radiolabeled 909-bp Ac-asp-1 fragment and the 602-bp Ac-asp-2 fragment were used as probes to screen the A. ceylanicum L3 cDNA library. Approximately 1×105 plaques of the A. ceylanicum L3 cDNA library were plated on 2 NZY agar plates. Plaque DNA was transferred to positively charged nylon membranes. After denaturation with alkali and stabilization by baking for 2 h at 80° C., the membranes were prehybridized for 2 h at 65° C. and then hybridized for 16 h in a solution of Rapid-hyb buffer (Amersham). Positive plaques were rescreened once, and the single positive clones were in vivo excised to phagemids by use of a helper phage (Stratagene). Double-strand sequencing was performed on the phagemid DNA by use of the generic vector primers T3 and T7. Sequence editing, alignments, and comparisons were performed by use of Eyeball Sequence Editor software (version 1.09e). Subcloning into Pichia Pastoris cDNA fragments encoding Ay-ASP-1 and Ay-ASP-2 (except for the predicted signal sequence) were amplified from pBluescript phagemids by use of specific primers for Ay-asp-1 (SEQ ID NO: 55): (Ay-asp-1) F1: 5-CTCTCGAGAAAAGAAGCCCAGTAAAGCCAGC-3 (SEQ ID NO: 70) and Ay-asp-1 R1: 5-TGTCTAGAGGAGCAC TGCACAATC-CTT C-3) (SEQ ID NO: 71) and Ay-asp-2 (SEQ ID NO: 57) (Ay-asp-2 F1: 5-GGGAATTCGGAAA-TAATGG AATGACCG-3 (SEQ ID NO: 72) and Ay-asp-2 R1: 5-TGTCTAGACCATGCACG-ATGCAAA GC-3) (SEQ ID NO: 73). The PCR products were then cloned into the eukaryotic expression vector pPICZαA (Invitrogen) by use of XhoI/XbaI sites for Ay-asp-1 and EcoRI/XbaI sites for Ay-asp-2 (SEQ ID NO: 57). The correct open-reading frame (ORF) was confirmed by sequencing that used the vector flanking primers corresponding to the regions encoding the a-factor and 3′ AOX1. The recombinant plasmids were linearized by use of SacI digestion and were transformed into the P. pastoris X33 strain by eletroporation, according to the manufacturer's instructions (Invitrogen). The transformants were selected on zeocin-resistant YPDA plates and identified by PCR amplification using the Ay-asp-1- and Ay-asp-2-specific primers (Ay-asp-1 F1/Ay-asp-1 R1 and Ay-asp-2 F1/Ay-asp-2 R1, respectively). Fermentation and Expression of Ay-ASP-1 (SEQ ID NO: 56) and Ay-ASP-2 (SEQ ID NO: 58) A culture inoculum was prepared from P. pastoris cells containing either the Ay-asp-1 or Ay-asp-2 gene in pPICZaA (In-vitrogen). The inoculum was prepared in 2 stages. In the first stage, 50 mL of buffered-complex glycerol medium with yeast (0.1 moVL potassium phosphate buffer [pH 6.0] containing 1% [wt/vol] yeast extract, 2% [wt/vol] peptone, 1.34% [wt/vol] yeast nitrogen base without amino acids, 1% [vol/vol] glycerol, and 4×10−5% d-biotin) in a 250-mL flask was inoculated with P. pastoris cells and grown for 24-36 h at 30° C., to a final OD600 nm of 10-20. In the second stage, 100 mL of buffered-complex glycerol medium without yeast extract was inoculated in a 500-mL shaker flask with 5-10 mL of P. pastoris cells from the first-stage culture and grown for 0.16 h at 30° C., to a final OD600 nm of 15-20. A Bioflo 3000 fermentor (New Brunswick Scientific), with a working volume of 5 L, was used for scale-up fermentation. Growth of P. pastoris in the fermentor was divided into glycerol and methanol phases. Glycerol phase. Approximately 50 mL of the shaker flask culture of P. pastoris cells was used to inoculate 2 L of heat-sterilized basal salt media (BSM) containing 2.5 mL/L filter-sterilized trace element (PTM1) solution. Each liter of BSM contained 0.93 g of CaSO4, 2H2O, 18.2 g of K2 SO4, 14.9 g of MgSO4, 7H2O, 4.13 g of KOH, 11.35 mL of 85% H3PO4, and 40 g of glycerol. The pH of the BSM was adjusted to 5.0 with 29% ammonium hydroxide. Dissolved oxygen was maintained above 35% throughout the fermentation. At 21-24 h into the initial glycerol phase (when a sharp increase in the percentage of dissolved oxygen was observed), 50% (vol/vol) glycerol was introduced into the cell culture media at a set flow rate of 15 g/L1 h for 6 h. The pH of the cell culture media was then increased linearly from 5.0 to 6.0 by adding 29% ammonium hydroxide. The temperature was decreased linearly from 30° C. to 26° C. over a 2-h period before the completion of this phase. Antifoam 204 (Sigma) was also added. Methanol phase. The methanol phase was initiated when the wet cell weight reached 225-250 g/L. Methanol was added at an initial flow rate of 1 mL/L/h, increasing to 9.0 mL/L/h over an 8-h period, and then subsequently maintained at a flow rate of 9.0 mL/L/h for 87 h. The wet cell weight was ˜465 and 479 g/L for cells expressing Ay-ASP-1 (SEQ ID NO: 56) and Ay-ASP-2, (SEQ ID NO: 58) respectively. Purification and Biochemical Characterization of Ay-ASP-1 and Ay-ASP-2 The cells were harvested, and supernatant was collected by centrifugation (8650 g for 20 min at 4C) by use of a Beckman JA-10 rotor (Beckman Instruments). The supernatant was then centrifuged a second time, to remove traces of cells and debris. Approximately 1.6 L of supernatant was filtered through a 0.8-m mol membrane (Fisher Scientific) and was concentrated to 200 mL by ultrafiltration by use of a 10,000 MWCO membrane (Pall Corporation); 2 L of binding buffer (20 mmol/L Tris-HCl, 5 mmol/L imidazole, and 0.5 mol/L NaCl [pH 7.9]) was added to the concentrated supernatant. The modified supernatant was then concentrated again to 200 mL by ultrafiltration, and the recombinant protein was isolated by immobilized metal ion affinity chromatography (IMAC) by use of a 1.25-mL pre-packed HisBind column (Novagen). The columns were washed with 8 mL of HisBind buffer (20 mmol/L Tris-HCl [pH 7.9] containing 0.5 mol/L NaCl), and the recombinant proteins were eluted with a stepwise gradient of the HisBind buffer containing 5 mmol/L, 20 mmol/L, 60 mmol/L, and 1.0 mol/L imidazole, as recommended by the manufacturer. The column eluates were analyzed by SDS-PAGE by use of 4%-20% Tris-glycine gels (Invitrogen) and were stained with Coomassie brilliant blue R-250 (CBB). The column fractions containing the purified Ay-ASP-1 (SEQ ID NO: 56) and Ay-ASP-2 (SEQ ID NO: 58) were identified by Western blot by use of an antihistidine tag monoclonal antibody (Novagen), goat antimouse IgG secondary antibody conjugated to horseradish peroxidase (ICN Biomedical), and the chemiluminescent detection system ECL+plus (Amersham Biosciences). Fractions containing purified Ay-ASP-1 (SEQ ID NO: 56) and Ay-ASP-2 (SEQ ID NO: 58) were concentrated by use of Amicon Ultra centrifugal filter devices (Millipore Corporation) with 30,000 and 10,000 molecular-weight cutoffs, respectively, and were desalted by use of PD-10 Columns (Amersham). Protein concentrations were determined by use of the BCA assay (Pierce) and also by SDS-PAGE using known quantities of bovine serum albumin as a control. N-terminal sequencing. SDS-PAGE analysis of Ay-ASP-1 (SEQ ID NO: 56) and Ay-ASP-2 (SEQ ID NO: 58) was performed on a 4%-20% gradient gel transferred to a polyvinyldene fluoride (immobilon-P) membrane (Millipore) at 250 mA for 1 h. The membrane was dried on filter paper for 15 min, soaked in 100% methanol, washed 5 times for 5 min/wash in MQ water (ultrapure water purified using the Milli-Q Water System; Millipore), and then stained with CBB. After drying, the visible bands were cut out, and—terminal amino acid sequences were obtained by Edman degradation, by use of a PE Biosystems 494 protein sequencer, at the Protein Chemistry Core Facility, Howard Hughes Medical Institute of Columbia University (New York, N.Y.). Irradiation of L3 Live A. ceylanicum L3 were irradiated with 40,000 rad in a Shepherd Mark IV Cesium 137 irradiator, model 25. To obtain homogeneity of irradiation exposure, a low exposure rate (but without an attenuator) and a moving turntable were used. The decay factor was considered while calculating the time of exposure. The irL3 were inspected by microscopy to ensure that they were actively motile and viable before and after irradiation. Hamster Vaccinations, Measurement of Anti-ASP Immune Responses, and Parasite Challenge Three-week-old male golden Syrian hamsters (Mesocricetus auratus) were vaccinated by intramuscular injection with 25 m g of either Ay-ASP-1 (SEQ ID NO: 56) or Ay-ASP-2 (SEQ ID NO: 58), each formulated with either Montanide ISA-720 (Seppic) or Quil A (Brenntag Biosector). To formulate each recombinant antigen with Quil A, 25 m g of the recombinant fusion protein was mixed, in a total volume of 95 m L, with 25 m g of Quil A, which was dissolved in 100 m L of PBS (pH 7.4). To formulate each recombinant antigen with Montanide ISA-720, 25 m g of the recombinant fusion protein was mixed, in a total volume of 60 m L, with 140 m L of Montanide ISA-720 and was shaken gently for 10 min at room temperature. The final volume was 200 m L for each antigen preparation per hamster. There were 10 hamsters in each group. The antigens were administered intramuscularly every 3 weeks on days 0, 21, and 42. An additional group of 10 hamsters was vaccinated by oral vaccination with 100 irL3 in 300 m L of PBS by use of the same vaccination schedule used for the other hamsters. Eight days after the final vaccination, the hamsters were bled retro-orbitally, and their IgG antibody responses to each of the recombinant antigens were measured by ELISA, as described elsewhere [31], by use of anti-hamster IgG conjugated with horseradish peroxidase (Rockland) as a secondary antibody. ELISA plates were developed with o-phenylenediamine substrate. Serum antibody titers were determined by measuring the last dilution that resulted in 3 SD above background. On day 56 after the initial vaccination (14 days after the final vaccination), each hamster was infected orally with 100 A. ceylanicum L3. The larvae were introduced directly into the stomach by use of a gavage tube. Measurement of Hookworm Burden, Hookworm Size, and Host Spleen Size The hamsters were killed at days 19-21 after infection, and the intestines and spleens were removed. The spleens were weighed, fixed in formalin, and examined histologically. The adult hook-worms in the intestines were removed, placed in triethanolamine and formalin fixative [26], and counted. Worm lengths were determined digitally as follows: preserved worms were photographed by use of a Cool Snap Pro CCD monochrome camera (Media Cybernetics) attached to a computer running Image Pro Plus software (version 4.1.0.0; Media Cybernetics). A macro was written to automatically determine the object endpoints and draw a “backbone” on the image of the worm. This allowed us to measure worms that were coiled or curved. The length of the digital line was determined automatically by use of the size (length) command in the software package. The software was calibrated by photographing a ruler at the same focal depth as the worms, and the lengths were expressed in centimeters. The measurements were exported to Microsoft Excel spread-sheets, and measurements derived from spurious images, such as debris or partial worms, were removed before analysis. Statistical Methods Hookworm burden reduction (vaccine protection) was defined as P=(AWC−AW I)/AWC, where P (protection) is expressed as percentage, AWC is the number of adult worms in the unvaccinated control hamsters (injected with adjuvant alone), and AWI is the number of adult worms in the hamsters vaccinated with recombinant antigen or irL3 [27]. The statistical significance of differences in adult hookworm burdens was determined by use of the Kruskal-Wallis and the Mann-Whitney U nonparametric tests. Mean spleen weights were compared by use of 1-way analysis of variance. After we determined that differences existed among the means, the Bonferroni post hoc test was used to determine which means differed. Mean lengths of adult worms were compared by use of the t test for 2 independent groups, assuming equal variances (Levene's test). Spleen weights and circulating hemoglobin were correlated by use of the Spearman's correlation. Differences were considered to be statistically significant if the calculated P<0.05. Results for Example 11. Cloning of Ay-asp-1 and Ay-asp-2. From 1×105 plaques screened for Ay-asp-1, 85 positive clones were obtained. A total of 21 positive clones were subjected to DNA sequencing. Of these, 19 sequences were identical, each encoding an ORF with homology to Ac-asp-1 (SEQ ID NO: 55) (designated as Ay-asp-1). The Ay-asp-1 cDNA included 1322 bp, with a 3 poly(A) tail, but lacked a 5′ initiation codon. The Ay-asp-1 cDNA encodes a predicted ORF of 424 aa that lacked 1 aa (Met) at the N-terminus, compared with Ac-ASP-1 (SEQ ID NO: 56). The predicted ORF of Ay-ASP-1 (SEQ ID NO: 56) has a calculated molecular weight of 45,748.46 Da and a predicted pI of 6.03. Two putative N-linked glycosylation sites were detected at Asn residues 58 and 120. Amino acid sequence comparisons among ASP-1 molecules from different species of hookworm larvae revealed that Ay-ASP-1 (SEQ ID NO: 56) exhibited 86% identity to Ad-ASP-1 (SEQ ID NO: 67) and 85% identity to both Ac-ASP-1 (SEQ ID NO: 18) and Na-ASP-1 (SEQ ID NO: 2) [28] (FIG. 42). From 1×103 plaques screened for Ay-asp-2, (SEQ ID NO: 57) 30 positive clones were obtained. A total of 10 were subjected to DNA sequencing. The sequences of these 10 clones were identical and encoded an ORF with close identity to the single-domain Ac-asp-2 (SEQ ID NO: 57) cDNA cloned previously from A. caninum [25]. The Ay-asp-2 cDNA included 740 bp, with a 3 poly(A) tail, but lacked a 5 initiation codon. The cDNA encoded an ORF of 217 aa that lacked 2 aa at the N-terminus, on the basis of its alignment with Ac-ASP-2 (SEQ ID NO: 20). The first 20 aa comprised a hydrophobic signal peptide sequence without an N-terminal Met. The predicted ORF of Ay-ASP-2 had a calculated molecular weight of 24,006 Da and a predicted pI of 8.04. No putative N-linked glycosylation site was detected in the sequence. The amino acid sequence comparison among ASP-2 molecules from different species of hookworm larvae revealed that Ay-ASP-2 (SEQ ID NO: 58) exhibited 83% identity to both Ac-ASP-2 (SEQ ID NO: 20) and Ad-ASP-2 (SEQ ID NO: 68) and 61% identity to Na-ASP-2 (SEQ ID NO: 69) (FIG. 43A). One additional amino acid (Pro) is inserted into residue 140 of Ay-ASP-2 (SEQ ID NO: 58), compared with other hookworm ASP-2 molecules. The placement of all cysteines was conserved among the ASP-1 and ASP-2 molecules. The cDNA sequence of Na-ASP-2 (SEQ ID NO: 82) is presented in FIG. 43B. Expression, purification, and biochemical characterization of recombinant Ay-ASP-1 and Ay-ASP-2. Both recombinant fusion proteins were secreted by P. pastoris during fermentation. The yields of Ay-ASP-1 (SEQ ID NO: 56) and Ay-ASP-2 (SEQ ID NO: 58) were 6 and 1 mg/L, respectively. In addition to the ORF, the recombinant Ay-ASP-1 (SEQ ID NO: 56) and Ay-ASP-2 (SEQ ID NO: 58) fusion proteins each contained C-terminal myc and histidine tags. N-terminal amino acid sequencing by Edman degradation of Ay-ASP-1 (SEQ ID NO: 56) identified a SPVKA sequence (data not shown), which is the predicted N-terminus following signal peptide removal. The Ay-ASP-2 (SEQ ID NO: 58) N-terminus comprised an EAEAEF expressed from the vector sequence flanking an EcoR1 site. This was also confirmed by Edman degradation (data not shown). The predicted molecular mass of the recombinant Ay-ASP-1 (SEQ ID NO: 56) and Ay-ASP-2 (SEQ ID NO: 58) fusions proteins, which contained these additional sequences, were 46,508 (428 aa) and 25,228 (225 aa) Da, respectively. SDS-PAGE analyses of the Pichia-expressed recombinant proteins during purification by IMAC showed that Ay-ASP-1 (SEQ ID NO: 56) and Ay-ASP-2 (SEQ ID NO: 58) migrated on SDS-PAGE with apparent molecular weights of 48 kDa and 30 kDa, respectively (not shown). Hamster immune responses to vaccination. The prechallenge IgG antibody titers in response to 3 vaccinations with ASP-1 or ASP-2 formulated with either Quil A or Montanide ISA-720 and 2 vaccinations with irL3 are shown in FIG. 44. In response to the ASP vaccination series, hamsters developed high anti-ASP-1 (1: 364,500) and anti-ASP-2 IgG (1: 135,609) titers when Quil A was used as the adjuvant and high anti-ASP-1 (1: 631,333) and anti-ASP-2 IgG (1: 135,609) titers when Montanide ISA-720 was used as the adjuvant, but only modest anti-L3 (1: 4500) titers. Because of the absence of commercially available antihamster secondary antibodies, no other immunoglobulin classes or subclasses were measured. Vaccination and challenge with A. ceylanicum L3. After oral challenge with 100 A. ceylanicum L3, statistically significant reductions in adult hookworm burden were noted among the hamsters vaccinated with either irL3 (58% reduction; P<0.001) or Ay-ASP-2 (SEQ ID NO: 58) formulated with Quil A (32%; P=0.025) (table VI). TABLE VI Hookworm burden reductions in hamsters after vaccination with Quil A alone (control group), recombinant Ay (Ancylostoma ceylanicum)-ASP-1 (SEQ ID NO: 56) Ancylostoma-secreted protein-1) formulated with Quil A, Ay-ASP-2 (SEQ ID NO: 58) formulated with Quil A, or irradiated A. ceylanicum third-stage infective larvae (L3), followed by A. ceylanicum L3 challenge. Reduction relative Adult hookworms, to Quil A-injected P, Groups mean ± SD hamsters, % one-sided Quil A alone 55.8 ± 12.1 — — Ay-ASP-1 44.4 ± 20.7 21 .16 formulated with Quil A Ay-ASP-2 37.9 ± 19.8 32 .025 formulated with Quil A Irradiated L3 23.4 ± 16.4 58 <.001 Statistically significant protection was not observed in hamsters vaccinated with Ay-ASP-1 (SEQ ID NO: 56) formulated with Quil A or with either ASP molecule formulated with the adjuvant Montanide ISA-720 (data not shown). In addition to reducing hookworm burden, as shown in table VII, vaccination with Ay-ASP-2 (SEQ ID NO: 58) formulated with Quil A reduced the size of the hook-worms by 14%, relative to that of the hookworms recovered from hamsters vaccinated with Quil A alone (P<0.001). TABLE VII Comparison of the mean lengths of hookworms recovered from hamsters after vaccination with Quil A alone (control group), recombinant Ay (Ancylostoma ceylani-cum)-ASP-1 (SEQ ID NO: 56) (Ancylostoma-secreted protein-1) formulated with Quil A, Ay-ASP-2 (SEQ ID NO: 58) formulated with Quil A, or irradiated A. ceylanicum third-stage infective larvae (L3), followed by A. ceylanicum L3 challenge. Reduction No. of Length, in worm Group worms mean ± SD, cm length, % P Quil A alone 464 0.50 ± 0.18 — — Ay-ASP-1 (SEQ 424 0.50 ± 0.17 0 .99 ID NO: 56) formulated with Quil A Ay-ASP-2 (SEQ 310 0.43 ± 0.18 14 <.001 ID NO: 58) formulated with Quil A Irradiated 217 0.47 ± 0.19 6 0.18 L3 The hamsters vaccinated with either Ay-ASP-2 (SEQ ID NO: 58) formulated with Quil A or irL3 experienced statistically significant reductions in host spleen size, compared with hamsters vaccinated with Quil A alone (table VIII). After host blood loss in hamsters infected with heavy hookworm burdens, the spleen expanded in size because of an influx of hematopoietic cells replacing lymphoid tissue. The extramedullary hematopoiesis was characterized by a pre-dominance of erythroblastic cells with deep blue cytoplasm and megakaryocytes (not shown). The spleens exhibited a statistically significant negative correlation (r=−0.5; P<0.01) with host circulating hemoglobin levels. In contrast, there were no statistically significant differences in splenic weights between hamsters vaccinated with both ASPs formulated with Montanide ISA-720 or with Montanide ISA-720 adjuvant alone (data not shown). As shown in table IX, hamsters vaccinated with either irL3 or ASP-1 formulated with Quil A also experienced less loss of body weight than did hamsters vaccinated with Quil A alone. TABLE VIII Weights of spleens recovered from hamsters after vaccination with Quil A alone (control group), recombinant Ay (Ancylostoma ceylanicum)-ASP-1 (SEQ ID NO: 56) (Ancylostoma-secreted protein-1) formulated with Quil A, Ay-ASP-2 (SEQ ID NO: 58) formulated with Quil A, or irradiated A. ceylanicum third-stage infective larvae (L3), followed by A. ceylanicum L3 challenge. Spleen weight, Group mean ± SD, g P Quil A alone 0.61 ± 0.07 — Ay-ASP-1 0.52 ± 0.09 .36 (SEQ ID NO: 56) formulated with Quil A Ay-ASP-2 0.46 ± 0.14 .025 (SEQ ID NO: 58) formulated with Quil A Irradiated L3 0.40 ± 0.09 <.001 TABLE IX Body-weight reductions of hamsters vaccinated with Quil A alone (control group), recombinant Ay (Ancylostoma ceylanicum)-ASP-1 (SEQ ID NO: 56) (Ancylostoma-secreted protein-1) formulated with Quil A, Ay-ASP-2 (SEQ ID NO: 58) formulated with Quil A, or irradiated A. ceylanicum third-stage infective larvae (L3). Group Mean (median) ± SD, g P Quil A alone 17.8 (17.0) ± 4.4 — Ay-ASP-1 (SEQ ID NO: 56) 17.8 (16.6) ± 4.9 .94 formulated with Quil A Ay-ASP-2 (SEQ ID NO: 58) 15.5 (14.3) ± 9.2 .27 formulated with Quil A Irradiated L3 10.8 (12.4) ± 4.9 .006 NOTE. Body weights were measured at necropsy and were compared with body weights at the time of experimental infection with L3. Discussion for Example 11. In studies performed during the 1960s, irL3 were shown to induce high levels of protective immunity in dogs, as evidenced by reduced hookworm burden and size and diminished blood loss [29]. These observations provided the basis for a commercial dog antihookworm vaccine that was marketed in Florida in 1973 and then in the eastern United States in 1974 [30]. The irL3 vaccine was later removed from commercial production because of its high cost and the requirement that the irL3 needed to maintain viability in order to release hookworm antigens [11, 21, 30]. Because administration of living L3 is not a viable strategy for human antihookworm vaccine development, an alternative approach might be to vaccinate animals with antigens secreted by living larvae; this, in turn, relies on the identification of the major L3 antigens secreted by the parasite at host entry and on cloning of the corresponding genes to produce recombinant proteins [11]. The results presented here have demonstrated that, in hamsters, recombinant ASP-2 derived from A. ceylanicum L3 elicits levels of protection comparable to levels elicited by irL3. Both asp-1 and asp-2 cDNAs were expressed in methanol by P. pastoris. The rationale for selecting yeast as an expression vector is that previous attempts to express asp cDNAs in Escherichia coli resulted in the production of expressed recombinant proteins in inclusion bodies. The E. coli-expressed proteins could not be refolded or solubilized. We and others have determined that E. coli fails to express proteins of the PRP superfamily in soluble form [11,31], most likely because their high cysteine content causes improper protein folding secondary to aberrant disulfide bond formation [11]. For instance, ASP-1 is a 45-kDa molecule containing 20 cysteines and 10 disulfide bonds in 2 PRP domains [24], whereas ASP-2 is a 24—kDa molecule containing 10 cysteines and 5 disulfide bonds in a single PRP domain [22, 25]. Other investigators have reported similar difficulties in expressing PRP superfamily proteins in prokaryotic systems [31]. One advantage of using P. pastoris, as opposed to other eukaryotic expression systems, such as insect and mammalian cells, is the comparatively high yields obtained from the yeast system, which allows recombinant proteins to be expressed at relatively low cost. It is anticipated that cost will be an important factor in the manufacture of human antihookworm vaccines targeted for the poorest of the poor in developing countries [32]. The ASPs were tested in laboratory hamsters challenged with A. ceylanicum. Although A. ceylanicum is considered to be only a minor cause of hookworm in humans, it has been adapted for use in studying the pathobiology of animal hookworm infections. Among the benefits of studying A. ceylanicum in hamsters is that heavy infections cause host blood loss leading to anemia [33]. This makes it possible to determine whether vaccination helps to reduce blood loss, as well as hookworm burden. Because the spleen increases in size and weight with extramedullary hematopoiesis caused by blood loss and anemia, the organ can be measured as a surrogate for measuring blood loss. However, the hamster model also suffers from some disadvantages for purposes of vaccine development. First, the hookworm is not a natural parasite of hamsters, and, second, there are very few immunological reagents to study the host immune response to either vaccination or infection. ASP-2 is the first recombinant vaccine antigen that has been shown to protect a permissive host (a host in which L3 complete their development to the adult stages) against hookworm at a level comparable to irL3. This molecule exhibits a high degree of amino acid similarity to Hc24, a protective antigen isolated from the trichostrongyle Haemonchus contortus [34-35], as well as a single-domain ASP protective antigen from Ostertagia ostertagi [36] and Onchocerca volvulus [37-38]. In sheep, Hc24-induced protection is dependent on antigen-specific host IgE [35]. The absence of hamster-specific immunological reagents made it impossible to measure antigen-specific IgE titers, although the antigen-specific IgG titers exceeded 1: 100,000 in the present study. In contrast, ASP-1 did not elicit comparable protection in hamsters, even though it elicited a strong immune response. The modest level of protection was disappointing, given that a fusion protein composed of a histidine tag and aa 96-428 of A. caninum ASP-1 was effective at blocking A. caninum L3 migrations in mice, when it was used as a vaccine with alum [39-41]. The basis for this difference is under investigation. The differences in protection noted between ASP-2 formulated with Quil A and ASP-2 formulated with Montanide ISA-720 are also under study. Quil A is a derivative of saponin and was chosen because it has been used successfully as an adjuvant for recombinant schistosome proteins in mice and water buffaloes [42, 43]. Montanide ISA-720 was chosen because of its previous use as an adjuvant in experimental human malaria vaccines [44, 45]. Without the benefit of available immunological reagents, however, it will be difficult to determine the qualitative differences in the immune response profiles of these 2 adjuvant formulations in hamsters. Because of the success of the ASP-2 homologue Hc24 in sheep and, in the present study, in hamsters, ASP-2 will be considered further for development and pilot manufacture of clinical-grade recombinant protein. Parallel studies have demonstrated that a small subset of humans living in regions of China and Brazil where hookworm is endemic acquire naturally circulating anti-ASP-2 antibodies. Early indications are that these individuals exhibit low hookworm burdens and are resistant to reinfection (date not shown). Moreover, in preliminary data from our laboratory, we have found some protection against A. caninum infections in dogs vaccinated with recombinant A. caninum ASP-2 (authors' unpublished data). Together with the results reported here, these data will be used to justify moving forward to human phase 1 clinical trials with Na-ASP-2 (SEQ ID NO: 69) as a lead vaccine candidate. References for Example 11 1. de Silva N, Brooker S, Hotez P, Montresor A, Engels D, Savioli L. Soil-transmitted helminth infections: updating the global picture. Trends Parasitol 2003; 19:547-51. 2. Hotez P J. China's hookworms. China Q 2002; 172:1029-41. 3. Stoltzfus R J, Chwaya H M, Tielsch J M, Schulze K J, Albonico M, Savioli L. Epidemiology of iron deficiency anemia in Zanzibari schoolchildren: the importance of hookworms. Am J Clin Nutr 1997; 65:153-9. 4. Stoltzfus R J, Dreyfuss M L, Chwaya H M, Albonico M. Hookworm control as a strategy to prevent iron deficiency. Nutr Rev 1997; 55:223-32. 5. Dreyfuss M L, Stoltzfus R J, Shrestha J B, et al. Hookworms, malaria and vitamin A deficiency contribute to anemia and irondeficiency among pregnant women in the plains of Nepal. J Nutr 2000; 130:2527-36. 6. Williamson A L, Brindley P J, Abbenante G, et al. Cleavage of hemoglobin by hookworm cathepsin D aspartic proteases and its potential contribution to host-specificity. FASEB J 2002; 16:1458-60. 7. Williamson A L, Brindley P J, Abbenante G, et al. Hookworm aspartic protease, Na-APR-2, cleaves human hemoglobin and serum proteins in a host-specific fashion. J Infect Dis 2003; 187:484-94. 8. Williamson A L, Brindley P J, Knox DP, Hotez P J, Loukas A. Digestive proteases of blood-feeding nematodes. Trends Parasitol 2003; 19: 417-23. 9. Murray C J L, Lopez A D. The global burden of disease. Global Burden of Disease and Injury Series. Geneva: World Health Organization, 1996. 10. World Health Organization (WHO). World Health Report 2002. Geneva: WHO, 2002. 11. Hotez P J, Zhan B, Bethony J M, et al. Progress in the development of a recombinant vaccine for human hookworm disease: the Human Hookworm Vaccine Initiative. Int J Parasitol 2003; 33:1245-58. 12. Albonico M, Crompton D W, Savioli L. Control strategies for human intestinal nematode infections. Adv Parasitol 1999; 42:277-341. 13. Hotez P J. Hookworm disease in children. Pediatr Infect Dis J 1989;8: 516-20. 14. Sakti H, Nokes C, Hertanto W S, et al. Evidence for an association between hookworm infection and cognitive function in Indonesian school children. Trop Med Int Health 1999; 4:322-34. 15. Stephenson L S, Latham M C, Kurz KM, Kinoti S N, Brigham H. Treatment with a single dose of albendazole improves growth of Kenyan schoolchildren with hookworm, Trichuris trichiura, and Ascaris lumbricoides infection. Am J Trop Med Hyg 1989; 41:78-87. 16. Bundy DAP. Is the hookworm just another geohelminth? In: Schad G A, Warren K S, eds. Hookworm disease, current status and new directions. London: Taylor & Francis, 1990:147-64. 17. Gandhi N S, Chen J Z, Koshnood K, et al. Epidemiology of Necator americanus hookworm infections in Xiulongkan Village, Hainan Province, China: high prevalence and intensity among middle-aged and elderly residents. J Parasitol 2001; 87:739-43. 18. Bethony J, Chen J Z, Lin S X, et al. Emerging patterns of hookworm infection: influence of aging on the intensity of Necator infection in Hainan Province, People's Republic of China. Clin Infect Dis 2002; 35:1336-44. 19. Bundy D A, Chan M S, Savioli L. Hookworm infection in pregnancy. Trans R Soc Trop Med Hyg 1995; 89:521-2. 20. Albonico M, Smith P G, Ercole E, et al. Rate of reinfection with intestinal nematodes after treatment of children with mebendazole or albendazole in a highly endemic area. Trans R Soc Trop Med Hyg 1995; 89:538-41. 21. Hotez P, Ghosh K, Hawdon J M, et al. Experimental approaches to the development of a recombinant hookworm vaccine. Immunol Rev 1999; 171:163-71. 22. Hawdon J M, Hotez P J. Hookworm: developmental biology of the infectious process. Curr Opin Genet Dev 1996; 6:618-23. 23. Zhan B, Hotez P J, Wang Y, Hawdon J M. A developmentally regulated metalloprotease secreted by host-stimulated Ancylostoma caninum third-stage infective larvae is a member of the astacin family of proteases. Mol Biochem Parasitol 2002; 120:291-6. 24. Hawdon J M, Jones BF, Hoffman D, Hotez P J. Cloning and expression of Ancylostoma secreted protein: a polypeptide associated with the transition to parasitism by infective hookworm larvae. J Biol Chem 1996; 271:6672-8. 25. Hawdon J M, Narasimhan S, Hotez P J. Ancylostoma secreted protein 2: cloning and characterization of a second member of a family of nematode secreted proteins from Ancylostoma caninum. Mol Biochem Parasitol 1999; 99:149-65. 26. Courtney W D, Polley D, Miller V L. TAF, an improved fixative in nematode technique. Plan Disease Reporter 1995; 39:570-1. 27. Hotez P J, Ashcom J, Zhan B, et al. Effect of recombinant fusion protein vaccinations on Ancylostoma caninum adult hookworm habitat selection in the canine intestine. J Parasitol 2002; 88:684-90. 28. Bin Z, Hawdon J, Qiang S, et al. Ancylostoma secreted protein 1 (ASP-1) homologues in human hookworms. Mol Biochem Parasitol 1999; 98:143-9. 29. Miller T A. Vaccination against the canine hookworm diseases. Adv Parasitol 1971; 9:153-83. 30. Miller T A. Industrial development and field use of the canine hook-worm vaccine. Adv Parasitol 1978; 16:333-42. 31. Monsalve R I, Lu G, King T P. Expression of recombinant venom al-lergen, antigen 5 of yellowjacket (Vespula vulgaris) and paper wasp (Polistes annulares), in bacteria or yeast. Protein Expr Purif 1999; 16: 410-6. 32. Hotez P J. Vaccines as instruments of foreign policy. EMBO Rep 2001;2: 862-8. 33. Bungiro R D Jr, Greene J, Kruglov E, Cappello M. Mitigation of hook-worm disease by immunization with soluble extracts of Ancylostoma ceylanicum. J Infect Dis 2001; 183:1380-7. 34. Schallig H, van Leeuwen M A, Cornelissen A W. Protective immunity induced by vaccination with two Haemonchus contortus excretory secretory proteins in sheep. Parasite Immunol 1997; 19:447-53. 35. Kooyman F N, Schallig H D, van Leeuwen M A, et al. Protection in lambs vaccinated with Haemonchus contortus antigens is age related, and cor-relates with IgE rather than IgG1 antibody. Parasite Immunol 2000; 22:13-20. 36. Geldhof P, Vercauteren I, Gevaert K, et al. Activation associated secreted proteins are the most abundant antigens in a host protective fraction from Ostertagia ostertagi. Mol Biochem Parasitol 2003; 128:111-4. 37. Lustigman S, James E R, Tawe W, Abraham D. Towards a recombinant antigen vaccine against Onchocerca volvulus. Trends Parasitol 2002; 18: 135-41. 38. Lustigman S, MacDonald A J M, Abraham D. CD4+dependent immunity to Onchocerca volvulus third-stage larvae in humans and the mouse vaccination model: common ground and distinctions. Int J Parasitol 2003; 33:1161-71. 39. Ghosh K, Hawdon J M, Hotez P J. Vaccination with alum-precipitated ASP-1 protects mice against challenge infections with infective hook-worm (Ancylostoma caninum) larvae. J Infect Dis 1996; 174:1380-3. 40. Ghosh K, Hotez P J. Antibody-dependent reductions in mouse hook-worm burden after vaccination with Ancylostoma caninum secreted protein 1. J Infect Dis 1999; 180:1674-8. 41. Sen L, Ghosh K, Bin Z, et al. Hookworm burden reductions in BALB/c mice vaccinated with Ancylostoma secreted protein I (ASP-1) from Ancylostoma duodenale, A. caninum and Necator americanus. Vaccine 2000; 18: 1096-102. 42. McManus D P, Wong J Y, Zhou J, et al. Recombinant paramyosin (rec-Sj-97) tested for immunogenicity and vaccine efficacy against Schistosoma japonicum in mice and water buffaloes. Vaccine 2001; 20:870-8. 43. Zhou J, Waine G J, Zheng Q, Zeng X, Yi X, McManus DP. B-cell epitopes recognized by Chinese water buffaloes (Bos buffelus) on the 22 kDa tegumental membrane-associated antigen (Sj-22) of the Asiatic blood-fluke, Schistosoma japonicum. Vet Re s 1999; 30:427-32. 44. Saul A, Lawrence G, Smillie A, et al. Human phase I vaccine trials of 3 recombinant asexual stage malaria antigens with Montanide ISA 720 adjuvant. Vaccine 1999; 17:3145-59. 45. Genton B, Al-Yaman F, Anders R, et al. Safety and immunogenicity of a three-component blood-stage malaria vaccine in adults living in an endemic area of Papua New Guinea. Vaccine 2000; 18:2504-11. Example 12 Antibodies Against a Secreted Protein from Hookworm Larvae Reduce the Intensity of Infection in Humans and Laboratory Animals An estimated 740 million people are infected with the hookworms Necator americanus or Ancylostoma duodenale in the tropics and subtropics1. New data employing disability adjusted life years (DALYs) reveals that hookworm disease outranks African trypanosomiasis, schistosomiasis, dengue, Chagas disease, and leprosy in terms of disease burden2. The major approach to hookworm control currently relies on periodic deworming through the administration of benzimidazole anthelmintic drugs. However, rapid re-infection after anthelmintic treatment3 and the diminishing efficacy of benzimidazoles with repeated use4 have made the successful development of an anti-hookworm vaccine an urgent public health need. The development of a hookworm vaccine requires an understanding of how protective immune responses are generated, both in individuals from endemic areas and laboratory animals under experimental conditions. Human and animal studies of helminth infections have established the importance of antibody-mediated protection, especially the protective role of parasite-specific IgE 5. For example, specific IgE against helminth antigens associates with reduced infection intensities (quantitative egg counts) to human infections with Schistosoma6,7, Trichuris8 and Ascaris9. Individuals with high levels of total and parasite-specific IgE had fewer and less fecund hookworms10,11. In laboratory animals, IgE mediates resistance to experimental schistosome infections in baboons12, nematode infections of sheep and cattle13,14 and nematode parasites of rodents15. Although the exact mechanisms by which IgE mediates protection are not known, it is thought to target degranulation of mast cells, basophils and eosinophils against the parasite5. With human and animal studies having established the importance of IgE-mediated protection against helminth parasites, we sought to identify antigens that elicit a strong, but not harmful, IgE response for the development of an effective hookworm vaccine. Based on the success of vaccinating laboratory animals with irradiated hookworm larvae16,17, we examined the antibody responses of individuals living in hookworm endemic areas against the most abundant antigens released by infective larval stages (L3) of hookworms, the Ancylostoma Secreted Proteins (ASPs). The ASPs belong to the pathogenesis related protein (PRP) superfamily18,19, and both ASP-1 and ASP-2 have been shown to be protective in rodent models of hookworm infection20,21. Cross-sectional studies from N. americanus endemic areas in Brazil and China, showed that the presence of IgE against ASP-2 associated with reduction in the intensity of infection. Subsequently, the protective role of ASP-2 in a canine experimental model of hookworm infection was confirmed. These parallel findings in humans and canines suggest that the presence of antibodies against ASP-2 results in a marked reduction in infection intensity, thus providing the strongest support yet for the development of an effective recombinant vaccine against human hookworm infection. Results for Example 12. Hookworm Infection Prevalence and Intensities in Brazil and China The prevalence (95% Confidence interval [CI]) of N. americanus infection in the Brazilian sample was 62% (58, 66%; n=245), with a mean (95% CI) epg of 301 (222, 350). The prevalence (95% CI) of N. americanus infection in the China sample 6 was 56% (51, 60%; n=257), with a mean (95% CI) epg of 971 (639, 1304). FIG. 45 shows that the middle-age and elderly age strata have the highest prevalence and intensity of infection in both samples. Infected People Generate Heterogeneous Antibody Responses to Crude Hookworm Extracts Sera from each blood sample were assayed for antibodies of each isotype to preparations of A. caninum crude antigen extracts, including third stage larval extract (L3E), adult extract (AE), and adult excretory/secretory (ES) products. L3 ES products were not available in sufficient quantities for serological analyses. Necator infected individuals produced all four IgG subclasses (IgG1, IgG2, IgG3, and IgG4) and IgE against A. caninum L3E, AE, and adult ES (data not shown). There was no association between levels of these antibodies and the age, sex, or intensity of infection in either study sample. A marked heterogeneity characterized the levels of antibody isotype produced to the crude antigen preparations among individuals of the same age, sex, and gender (not shown). Expression of Recombinant, Secreted ASP-2 in Insect Cells Ac-ASP-2 (SEQ ID NO: 20) was secreted a concentration of approximately 2 mg.L−1 by Sf9 cells into culture medium. The protein was purified using nickel-NTA agarose and resolved as two closely migrating bands of 24-25 kDa (not shown). Both bands were recognized by monoclonal antibodies raised to the vector-derived, C-terminal V5 and His epitopes (not shown). The five N-terminal amino acids were sequenced from both bands and they were identical: G-M-R-N-S where G-M-R is derived from the restriction site in the cloning vector, and N-S are the first two amino acids of mature7 (processed) Ac-ASP-2 (SEQ ID NO: 20). Mass spectroscopy revealed the molecular weight of the major peak to be 24,492.2 Da (FIG. 46); this is in agreement with the predicted molecular weight of the secreted fusion protein (25,439.9 Da) in the absence of glycosylation. Ac-ASP-2 (SEQ ID NO: 20) was predicted to contain one N-linked glycosylation site at Asn-204, and treatment of the recombinant protein with PNGaseF removed the majority of protein that resolved in the upper band (data not shown). O-glycosidase treatment did not have an effect on the apparent molecular weight of recombinant Ac-ASP-2 (SEQ ID NO: 20). Rabbit antiserum raised to ASP-2 recognized the recombinant antigen as well as a protein of the expected size in L3 extracts from N. americanus (not shown), indicating that N. americanus L3 produce a protein with immunologic similarity to Ac-ASP-2. (SEQ ID NO: 20). A molecular model of Ac-ASP-2 (SEQ ID NO: 20) based on the known structure of a PRP family member (Ves v 5 from the yellow jacket) showed that the two sequences shared significant identity in fold, despite only 26% identity at the primary sequence level (not shown). ASP-2 retained the general α.β.α core sandwich fold displayed by PRPs 22. IgE Against ASP-2 Associates with Reducedfecal Egg Counts in Infected People Necator-infected individuals were classified into one of five profiles based on the predominant isotype response to recombinant ASP-2: (1) no isotype, (2) IgG1 only, (3) IgG4 only, (4) IgE only, or (5) combined IgG4 and IgE. FIG. 4a graphically represents the relative proportions of each antibody isotype profile from both endemic areas. The largest group consisted of infected individuals who either failed to mount an antibody response to ASP-2 (29% in both areas) or mounted an IgG4 response (34% in China and 26% in Brazil). Individuals who mounted only an IgE response to ASP-2 constituted 18% of the Chinese sample and 19% of the Brazilian sample. The 8 combined IgG4 and IgE response was consistently the smallest group (9%). As shown in immunoblots (not shown), individuals who mounted an IgE response to ASP-2 did not mount an IgG1 response. Individuals who mounted an IgG1 response did not mount an IgE response (not shown). We did not observe an IgG2 or IgG3 response to ASP-2 in the serum of any individual. Infected individuals who were positive for IgE against Ac-ASP-2 (SEQ ID NO: 20) from China (FIG. 48a) and Brazil (FIG. 48b) had marked (74% and 69%, respectively) and significantly (P<0.001 for both) reduced fecal egg counts compared to infected individuals who did not produce IgE against ASP-2. It should be emphasized that the presence or absence of an IgE response to ASP-2, and not the quantitative nature of the response, was associated with a significant reduction in infection intensity. Individuals who were positive for both IgG4 and IgE to ASP-2 also had reduced (30% for China and 25% for Brazil) but not significantly (P=0.123) different fecal egg counts. Sera from patients from both endemic areas were also assayed for the antibody isotype response to ASP-1, a heterodimeric protein with a duplicated PRP domain (compared with ASP-2 which has a single PRP domain). While a vigorous and heterogenous antibody isotype response was detected for IgG1, IgG3, IgG4, and IgE to ASP-1, there was no association between these responses and infection intensity, age, gender or the antibody response to crude hookworm extracts (not shown). Vaccination of Dogs with Recombinant Ac-ASP-2 (SEQ ID NO: 20) Confers Protection Against Hookworm Infection Canines immunized with recombinant Ac-ASP-2/AS03 produced strong IgG1 and IgG2 antibody titers to recombinant Ac-ASP-2 (SEQ ID NO: 20)(FIG. 49). The IgE titers to Ac-ASP-2 (SEQ ID NO: 20) in the test canines were one log lower than the IgG1 and IgG2 titers. Dogs immunized with AS03 adjuvant alone did not generate detectable antibody responses to Ac-ASP-2 (SEQ ID NO: 20) prior to larval challenge. Sera from dogs vaccinated with recombinant ASP-2 immunoprecipitated native ASP-2 from biotinylated A. caninum extracts (L3E) (not shown), while sera from animals immunized with adjuvant alone did not precipitate any L3E proteins. We observed a marked (69%) and significant (P=0.025) reduction in fecal egg counts in animals vaccinated with ASP-2 compared with control animals (FIG. 50a). We also observed a marked (30%) and statistically significant (P=0.044) reduction in adult worms retrieved during necropsy from the colon and small intestine of animals vaccinated with ASP-2 (FIG. 50b). Sera from dogs immunized with ASP-2 but not control sera interfered with migration (30% reduction) of A. caninum L3 through canine skin in vitro (FIG. 50c). There was a strong association (r 2=0.86; P=0.037) between adult worm burden in the intestine and the inhibitory effect of serum from vaccinated canines on the ability of A. caninum L3 to penetrate canine skin in vitro (not shown). Discussion for Example 12. Here we show that individuals who mount an IgE response to ASP-2 have markedly reduced intensity of hookworm infection. Vaccination of dogs with recombinant ASP-2 also resulted in protection as measured by reduced fecal egg counts and decreased worm burdens. Finally, sera from dogs vaccinated with ASP-2 reduced the ability of A. caninum L3 to migrate through canine skin in vitro. This is the first study to observe an association between an antibody response to a recombinant antigen and a reduction in intensity of both human and animal hookworm infections. The ASPs are cysteine rich secretory proteins (CRISPs) belonging to the PRP superfamily22. All parasitic nematodes investigated to date, including the major species of animals18,19,23-25 and humans26-28, secrete PRPs. Available data suggest that the PRPs play diverse roles in nematode parasitism by binding to host cells. For example, nematode PRPs interfere with neutrophil recruitment by binding to integrins29, combat hemostasis by binding to platelets and inhibiting their activation30, and elicit angiogenesis in vitro27. The observation that hookworm ASP-2 is released by L3 after their stimulation with serum suggests its importance during the early stages of host larval invasion19,31. Therefore, specific antibody responses against ASP-2 might interrupt the physiologic function of this nematode PRP. ASPs are the most abundant antigens recognized in host protective fractions of secretory products from nematode parasites of sheep14 and cattle23. In the former study, protection was mediated by antigen-specific IgE. We now show that IgE against hookworm ASP-2 is associated with reduced infection intensity in humans. Our findings are consistent with other studies on the role of IgE in immunity to N. americanus10. Based upon the observation that sera from canines vaccinated with ASP-2 inhibited A. caninum L3 entry through skin in vitro, we strongly suspect that antibodies may be working to reduce the number of L3 that ultimately enter the gastrointestinal tract by first targeting them during cutaneous entry. Two convergent lines of evidence further support this theory. First, asp-2 mRNA is transcribed only by the L3 stage and ASP-2 protein is released by L3 only under host stimulatory conditions19. Therefore, ASP-2 functions during the larva's transition from the external environment to parasitism upon entry into the host19,31. In addition, natural and experimental infections with schistosomes suggests that IgE is an important component in the elimination of penetrating larvae12. The effects of anti-ASP-2 antibody may also extend beyond direct damage to invading larvae. Dogs vaccinated with ASP-2 had a marked reduction in adult worm fecundity, and hamsters vaccinated with the Ancylostoma ceylanicum orthologue of ASP-2 exhibited marked reduction in both adult worm burdens and worm size21. ASP-2 protein is not detected in adult parasites, however the anti-fecundity effect of vaccination with ASP-2 may be attributed to immunologic damage caused to L3 that go on to mature to adulthood. As larvae mature, sexual organogenesis occurs; if larvae are damaged or immunologically attenuated, some might be expected to reach maturity but in a compromised state, e.g., sterile or sexually immature. This is consistent with the observation that some radiation-attenuated helminth larvae develop into sterile adult worms32, Therefore, it is likely that the anti-fecundity effect induced by vaccination with ASP-2 is a result of both fewer worms reaching adulthood in the intestine, as well as a compromised reproductive capacity of those parasites that finally reach the gut. The major clinical manifestations of hookworm disease are the consequences of iron deficiency, anemia and hypoalbuminemia, which develop when blood loss exceeds host iron and protein intake and reserves33. By these mechanisms, hookworm is increasingly recognized as a major global cause of iron-deficiency anemia, the world's most important nutritional deficiency34. Hookworm fecal egg counts correlate positively with host blood loss, and negatively with circulating hemoglobin concentration and iron status35. Therefore, the observation that anti-ASP-2 antibodies associate with reduced fecal egg counts and worms burdens has important clinical implications, and support the development of ASP-2 as a hookworm vaccine. ASP-2 fulfils many of the criteria required for an efficacious hookworm vaccine. The optimal vaccine would have the following features: (1) it would decrease the number of L3 that reach the gastrointestinal tract; (2) it would prevent development of L3 into blood-feeding adult hookworms, and (3) it would block the survival and fecundity of adult hookworms34,36 Achieving all three goals will likely require a combination vaccine comprised of ASP-2 from the L3, in addition to an essential proteolytic enzyme for adult hookworm blood-feeding37,38 Development, manufacture, and clinical testing of such a combination vaccine are in progress 36 Materials AND Methods for Example 12. Patient Sample The village of Daocong is located on the north of Hainan Island, China. Five hundred and ninety-one individuals were registered with the Daocong village administration. Three inclusion criteria were applied to the sample: (1) continuous residence in the endemic area over the last two years, (2) willing and able to comply with the study protocol Including blood and fecal samples); and (3) no prior treatment for hookworm during the previous two years as determined by survey. Three-hundred and ninety-six (67%) met all inclusion criteria. The 195 individuals not participating in the study did not differ by age (P=0.30), gender (P=0.35), occupation (P=0.43), or area of residence within the village (P=0.40). All research was performed in accordance with the ethical standards of the Yale University Human Investigations Committee (protocol 10932), the Internal Review Board (IRB) of the George Washington University Medical Center (protocol 080004), and the Institute of Parasitic Diseases through a single project assurance from the National Institutes of Health. Each house was assigned a unique household identification number (HHID) and each resident a unique personal identity number (PID). Individuals excluded from the analysis received a fecal examination and were treated for any diagnosed helminth infection. Five hundred and twenty one individuals were enumerated in the study area of Virgem das Gracas is located in Minas Gerais State, Brazil. All research was performed in accordance with the Ethics Committee of the Centro de Pesquisas de Rene Rachou, FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil (06-2002 and 02-2002) and the IRB of the George Washington University Medical Center (090303EX). At this time, each house was assigned a unique HHID and each resident a unique PID. The 3 inclusion criteria applied to the Hainan study sample were also applied here. Four-hundred and fifty-nine (88%) individuals met all three inclusion criteria. The 62 individuals not participating in the study did not differ by age (P=0.66), gender (P=0.33), occupation (P=0.21), or area of residence within the village (P=0.22). Each house was assigned a unique household identification number (HHID) and each resident a unique personal identity number (PID). Individuals excluded from the analysis received a fecal examination and were treated for any diagnosed helminth infection. Sera from 30 volunteers from a non-Necator endemic area in Minas Gerias, Brazil, who were egg-negative at the time of blood draw, were pooled and used as an “endemic negative control” on each ELISA plate. Sera from 28 volunteers from the United States were pooled and used as a “non-endemic negative control” on each ELISA plate. Recombinant Protein Expression Recombinant Ac-ASP-2 (SEQ ID NO: 20) was expressed in Spodpotera frugiperda Sf9 insect cells using the pMIB-V5/His expression system (Invitrogen, Carlsbad, Calif.). The entire ASP-2 open reading frame (GenBank accession number AF 089728) minus the N-terminal signal peptide (from Asn-18 to the C-terminal Gly-218) was cloned into pMIB-V5/HisA using the SphI and XbaI restriction sites so that the recombinant ASP-2 was fused in-frame with the vector-derived N-terminal melittin signal peptide and C-terminal V5 and 6-His epitopes. Sf9 cells were grown in Excell 420 medium (JRH Bioscience, Lenexa, Kans.) and transfected with ASP-2 plasmid midi-prep (Qiagen, Valencia, Calif.) and Genejammer transfection reagent (Stratagene, La Jolla, Calif.) according to the manufacturer's instructions. Transfected cells were selected using Blasticidin S (Cayla, Toulouse, France) at a final concentration of 25 μg.ml−1 in 6 well plates and maintained in 10 μg.ml−1 blasticidin after selection. Selected cells were transferred successively from adherent populations to shaker flasks according to the manufacturer's instructions (Invitrogen). Stably selected cells in log phase were then used to seed a total of 4 liters of Excel 420 medium to a final cell density of 1.0×106 cells per ml in a Bioflo 10 bioreactor (New Brunswick Scientific, Edison, N.J.) with a 7.5 liter vessel. The cells were maintained at a temperature of 27□C. and stirred at 70 rpm in the presence of 55-80% dissolved O2. pH was not adjusted and remained between 6.1-6.4. Cells were grown until a cell density of 1.0×107 cells per ml was attained. Supernatant was harvested by centrifugation at 4,000×g and concentrated 10-fold by ultrafiltration using a 10 kDa cut-off ultrasette membrane (Pall Corporation) and peristaltic pump. Concentrated supernatant containing recombinant ASP-2 was buffer-exchanged into milliQ H2O followed by binding buffer (0.05M NaH2PO4, 0.3M NaCl, 10 mM imidazole, pH 8.0) before being applied to a nickel-NTA agarose column (Novagen, EMD Biosciences, Darmstadt, Germany) with a settled bed volume of 2.0 ml. The column was washed with 10 volumes of binding buffer followed by 5 column volumes each of 20, 40 and 60 mM imidazole in binding buffer. Proteins were eluted in 5 column volumes of 250 mM imidazole in binding buffer. Fractions were assessed for recombinant protein and resulting purity by SDS-PAGE using pre-cast 4-20% Tris-glycine gradient mini gels (Invitrogen) stained with Coomassie Brilliant Blue (CBB). Fractions containing purified protein were pooled, concentrated and buffer-exchanged into PBS, pH 7.2 at 4° C. Protein concentration was determined using a micro BCA kit (Pierce, Rockford, Ill.). Molecular Modeling The predicted structure of Ac-ASP-2 (SEQ ID NO: 20) was determined by modeling the amino acid sequence against all coordinates in the RCSB Protein Data Bank using the first-approach mode in Swiss-Model. Pdb files generated were refined and viewed using Swiss-PdbViewer 3.7. Biochemical Analyses of Recombinant Ac-ASP-2 Recombinant Ac-ASP-2 (SEQ ID NO: 20) (2.0 μg) was transferred to PVDF membrane, stained with CBB, destained and rinsed extensively in distilled H2O before being submitted for Edman degradation at Columbia University Protein Core Facility, NY. Molecular weight determinations and purity were determined by Matrix-Assisted Laser Desorption Ionization, Time of Flight (MALDI-TOF) spectroscopy using an AXIMA-16 CFR instrument (Kratos Analytical Inc., Chestnut Ridge, N.Y.) by Dr Paolo Lecchi at The George Washington University Proteomics facility. The glycosylation status of recombinant Ac-ASP-2 was assessed using an Enzymatic CarboRelease kit (QA-Bio, San Mateo, Calif.) under denaturing conditions to remove any N-linked and O-linked oligosaccharides. Production of Rabbit Anti-Ac-ASP-2 Serum and Western Blotting Ac-ASP-2 (SEQ ID NO: 20) was formulated with Freund's Complete Adjuvant (first immunization) and Freund's Incomplete Adjuvant (second-fourth immunizations) using standard procedures. An antiserum against formulated Ac-ASP-2 (SEQ ID NO: 20) was raised in a rabbit by immunizing with 150 μg of recombinant protein per dose. The rabbit was immunized four times at 3 weekly intervals. Blood was drawn before the first and one week after the final immunization and sera were recovered. Western blotting was used to determine the antigenicity of recombinant Ac-ASP-2 (SEQ ID NO: 20) and to identify the protein in L3 extracts of N. americanus. Twenty-five nanograms of recombinant protein or 1.0 μg of larval extracts were separated on a 4-20% gradient SDS polyacrylamide gel and subsequently transferred to PVDF membrane. After transfer, the membrane was blocked with 5% non-fat dry milk in TBS/0.05% Tween-20 (TBST) overnight, and then probed with a 1:20,000 dilution of rabbit serum (pre- and post-vaccination) for one hour. After three washes with TBST, the membrane was incubated with horseradish peroxidase-conjugated goat anti-rabbit IgG (heavy and light chains) for one hour. Bands were visualized using ECL plus enhanced chemiluminescence (Amersham Biosciences, Piscataway, N.J.). Parasitological Methods The presence of intestinal nematode eggs was determined by saline float. In the case of a positive fecal sample, 3 subsequent fecal samples were taken over the course of 3 days. Two slides from each day's fecal sample were prepared within 24 hours of receipt using the Kato-Katz thick smear technique. Hookworm species (A. duodenale or N. americanus) were determined by morphological identification of third stage larvae reared from eggs by coproculture39. Indirect ELISA. Serum samples were obtained from whole blood collected into siliconized tubes. Serum was separated by centrifugation at 800×g for 10 min; the resulting serum supernatant was transferred to sterile 1 mL tubes and stored at −80° C. An indirect ELISA was then used to study isotype responses of participants to three crude A. caninum antigen preparations. Nunc Maxisorp Surface 96 well plates (Nalge Nunc International, Rochester, N.Y.) were coated with 0.5 μg/well of crude antigen preparation in 20 mM sodium bicarbonate/27 mM sodium carbonate, pH 9.6 and stored overnight at 4° C. For IgG2 assays, 96-well plates were adsorbed overnight at room temperature with 100 μl/well of Poly-L-lysine at 1 μg.mL−1 in 50 mM sodium carbonate, pH 9.0. Plates were then washed with PBS and crude antigen added and incubated in the manner described above. Plates were washed 5 times with PBS, pH 7.2, and then blocked for 1 h with PBS containing 1% fetal calf serum. Plates were washed 5 times with PBST. Serum samples were diluted 1:100 in PBST, and 100 μL/well was added in duplicate. Plates were incubated overnight at 4° C. and then washed 5 times with PBST as before. One hundred μL of the following dilutions of horseradish peroxidase-conjugated anti-human antibodies (Zymed, San Francisco, 18 CA) were added to each well: 1:5,000 of IgG1; 1:1,000 of IgG2, IgG3 and IgG4; and 1:800 of IgE. The plates were incubated for 1 h at RT and then washed 10 times with PBST. One hundred AL per well of Ortho-Phenylenediamine (OPD, Sigma-Aldrich, St Louis, Mo.) containing 0.03% hydrogen peroxide was then added. Plates were developed for 30 minutes in the dark. The reaction was stopped with 50 μL per well of 30% H2SO4 and the Optical Density (OD) measured at 492 nm on an automated ELISA reader (Molecular Devices, Sunnyvale, Calif.). We considered sera to be positive for an isotype response to a defined antigen when the OD reading for the isotype against Ac-ASP-2 was 3 SD above the combined mean OD of the USA and Brazil controls. Assays were standardized according to previously described methods40. Sera used in the IgE-ELISA were not de-adsorbed for other isotypes because of the observation that people who produced IgE did not produce IgG 1 and vice versa. Data Entry and Statistical Methods for Human Studies All research on human subjects was conducted by trained personnel by the standards of Good Clinical Practices. Data from case report forms were double-entered into an Excel file and then transferred to SPSS 10.00. Conflicts in double entry of data were resolved by referring to source documents. Student's t-test was used to determine significant differences in means for normally distributed continuous variables for two independent effects. ANOVA was used to test the mean differences of continuous variables when an effect consisted of more than one group (e.g., 10-year age intervals). Bonferroni post hoc tests, with a significance level of 0.05, were used for multiple pair-wise testing normally distributed continuous variables. A chi-square test was used to test the significance of proportions of egg positive and negative individuals. A Pearson product moment correlation was used for all19 correlations among normally distributed variables. Spearman correlation coefficient was used as a nonparametric measure of correlation between ordinal variables. For all of the cases, the values of each of the variables were ranked from smallest to largest, and the Pearson correlation coefficient was computed on the ranks. Before calculating a correlation coefficient, data were screened for outliers. Animal Husbandry and Vaccination The test and control animals were purpose bred, parasite naïve male beagles 56±4 days of age (body weights equal to or exceeded 2.5 kg, hematocrit equal to or exceeded 28.0, WBC did not exceed 20×106) on arrival. All dogs in a trial were purchased from the same vendor (Marshall Farms, North Rose, N.Y.), identified by ear tattoo, and maintained in the George Washington University Animal Research Facility as previously described37. The experiments were conducted according to a protocol approved by the George Washington University Animal Care and Use Committee. Dogs were housed in groups for approximately one month and 1 to 3 animals per cage thereafter; controls were housed identically to test animals. Following larval challenge, all dogs were individually housed. A serum sample was obtained from each dog before the first and after each subsequent vaccination. Crude Hookworm Antigen Preparation. A. caninum L3 were harvested and homogenized to generate soluble extracts (L3E) as previously described41. Adult A. caninum ES proteins and somatic extracts (AE) were prepared as previously describedhu 25,42. N. americanus L3 were harvested and soluble extracts prepared as described elsewhere. Protein concentrations were measured using the BCA protein assay kit (Pierce). Vaccine Study Design and Antigen-Adjuvant Formulation This study was conducted and reported in compliance with the intent of the Good Laboratory Practice Regulations (F.R. Vol. 43, No. 247, pp. 60013-60025, Dec. 22, 1978 and subsequent amendments). The study was audited by Quality Assurance while in progress to assure compliance with GLP regulations, adherence to the protocol and standard operating procedures. The data and final report were audited by Quality Assurance to assure that the report accurately described study conduct and results. The vaccine trial was designed to test Ac-ASP-2 formulated with Adjuvant System 03 (AS03) 44 obtained from GlaxoSmithKline. The rationale for selecting AS03 as an adjuvants is discussed elsewhere 37. The ten purpose bred beagles were randomized into two arms: immunized with Ac-ASP-2 (SEQ ID NO: 20) or adjuvant only (control). To make six doses of Ac-ASP-2 (SEQ ID NO: 20) formulated with AS03, 600 μg of recombinant protein (0.3 ml of Ac-ASP-2 (SEQ ID NO: 20) at a concentration of 2 mg.ml−1) was mixed with 1.2 ml of 20 mM Tris-HCl, 0.5 M NaCl, pH 7.9 and 1.5 ml of AS03; the contents of the tube were vortex mixed for 30 seconds then shaken at low speed for 10 minutes. Dogs were immunized with 100 μg of formulated antigen in a final volume of 0.5 ml. AS03 only control was prepared as described above, with PBS included instead of Ac-ASP-2 (SEQ ID NO: 20). Formulation of GSK adjuvants were conducted according to the protocol provided by GSK. All injections were performed intramuscularly (IM). Test and control articles were prepared on the day of injection. Hookworm Infections and Parasite Recovery A. caninum larvae were cultured from eggs collected in the feces of infected dogs. All hookworms in the infective challenge were approximately equal age (17±7 days post hatching). The species identity of the infective larvae were validated using PCR 45. All dogs were infected by the footpad method with the same dose of 500 L3 of A. caninum 37. Larval challenge occurred on one of three consecutive days (at age 120±9 days). Fourteen-sixteen days after the final immunization, dogs were anaesthetized using a combination of ketamine and xylazine (20 mg.kg−1 and 10 mg.kg−1 respectively), and 500 A. caninum L3 in a final volume of 50 μl were applied to the footpad. Canine Immunizations and Antibody Measurements Beagles were immunized with formulated Ac-ASP-2 (SEQ ID NO: 20) as previously described37. The vaccines were administered IM three times beginning at age 62±4 days. Boosts were administered to the dogs at intervals of 21 days. Blood was drawn at least once every 21 days and serum was separated from cells by centrifugation. Each animal's specific antibody response was evaluated by indirect ELISA using serum taken prior to the infective challenge37. Recombinant Ac-ASP-2 (SEQ ID NO: 20) was coated onto microtiter plates at a concentration of 51 g.ml ˜1. Dog sera were titrated between 1: 100 and 1:2×106 to determine endpoint titers. Anti-canine IgG1, IgG2 and IgE antibodies conjugated to horse-radish peroxidase (Bethyl Laboratories, Montgomery, Tex.) were used at a dilution of 1: 1,000. L3 Skin Penetration Assays Live A. caninum L3 were incubated with sera (neat) from immunized dogs then L3 were placed on canine skin to observe whether serum antibodies interfered with the penetration of skin in vitro46. Briefly, fresh skin from the ear of a dog was shaved, and approx. 4 cm 2 section of skin was stretched and sandwiched between 2×20 mL syringe barrels that were clamped together with bulldog clips. The lower syringe was filled to the top with PBS so that the buffer was in contact with the underside of the skin. One milliliter of PBS was placed on the skin for 15 min to check integrity of the skin. L3 (300 L3/group) were then incubated in 0.05 ml of PBS, pH 7.2, or undiluted serum from different vaccinated or control dogs for 30 min at 37° C. Each group of L3 were then placed on the upper side of the skin (added to the 1.0 ml of PBS already present) and allowed to migrate for 30 min at RT. L3 that remained on the surface of the skin were collected and counted, by removing the remaining liquid with a pipette and washing the skin with 2 volumes of PBS. Each assay was performed in triplicate. References for Example 12 1. de Silva, N. R. et al. Soil-transmitted helminth infections: updating the global picture. Trends Parasitol 19, 547-51 (2003). 2. WHO. The world health report 2002. Reducing risks, promoting healthy life. (2002). 3. Albonico, M. et al. Rate of reinfection with intestinal nematodes after treatment of children with mebendazole or albendazole in a highly endemic area. Trans R Soc Trop Med Hyg89, 538-41 (1995). 4. Albonico, M. et al. Efficacy of mebendazole and levamisole alone or in combination against intestinal nematode infections after repeated targeted mebendazole treatment in Zanzibar. Bull World Health Organ 81, 343-52 (2003). 5. Garraud, O., Perraut, R., Riveau, G. & Nutman, T. B. Class and subclass selection in parasite-specific antibody responses. Trends Parasitol 19, 300-4 (2003). 6. Hagan, P., Blumenthal, U. J., Dunn, D., Simpson, A. J. & Wilkins, H. A. Human IgE, IgG4 and resistance to reinfection with Schistosoma haematobium. Nature 349, 243-5 (1991). 7. Dunne, D. W. et al. Immunity after treatment of human schistosomiasis: association between IgE antibodies to adult worm antigens and resistance to reinfection. Eur J Immunol 22, 1483-94 (1992). 8. Faulkner, H. et al. Age- and infection intensity-dependent cytokine and antibody production in human trichuriasis: the importance of IgE. J Infect Dis 185, 665-72 (2002). 9. McSharry, C., Xia, Y., Holland, C. V. & Kennedy, M. W. Natural immunity to Ascaris lumbricoides associated with immunoglobulin E antibody to ABA-1 allergen and inflammation indicators in children. Infect Immun 67, 484-9 (1999). 10. Pritchard, D. I., Quinnell, R. J. & Walsh, E. A. Immunity in humans to Necator americanus: IgE, parasite weight and fecundity. Parasite Immunol 17, 71-5 (1995). 11. Loukas, A. & Prociv, P. Immune responses in hookworm infections. Clin Microbiol Rev 14, 689-703 (2001). 12. Nyindo, M. et al. Role of adult worm antigen-specific immunoglobulin E in acquired immunity to Schistosoma mansoni infection in baboons. Infect Immun 67, 636-42 (1999). 13. Huntley, J. F. et al. IgE responses in the serum and gastric lymph of sheep infected with Teladorsagia circumcincta. Parasite Immunol 20, 163-8 (1998). 14. Kooyman, F. N. et al. Protection in lambs vaccinated with Haemonchus contortus antigens is age related, and correlates with IgE rather than IgG1 antibody. Parasite Immunol 22, 13-20 (2000). 15. Negrao-Correa, D., Adams, L. S. & Bell, R. G. Variability of the intestinal immunoglobulin E response of rats to infection with Trichinella spiralis, Heligmosomoides polygyrus or Nippostrongylus brasiliensis. Parasite Immunol 21, 287-97 (1999). 16. Girod, N., Brown, A., Pritchard, D. I. & Billett, E. E. Successful vaccination of BALB/C mice against human hookworm (Necator americanus): the immunological phenotype of the protective response. Int J Parasitol 33, 71-80 (2003). 17. Miller, T. A. Persistence of immunity following double vaccination of pups with x-irradiated Ancylostoma caninum larvae. J. Parasitol. 51, 705-11 (1965). 18. Hawdon, J. M., Jones, B. F., Hoffman, D. R. & Hotez, P. J. Cloning and characterization of Ancylostoma-secreted protein. A novel protein associated with the transition to parasitism by infective hookworm larvae. J Biol Chem 271, 6672-8 (1996). 19. Hawdon, J. M., Narasimhan, S. & Hotez, P. J. Ancylostoma secreted protein 2: cloning and characterization of a second member of a family of nematode secreted proteins from Ancylostoma caninum. Mol Biochem Parasitol 99, 149-65 (1999). 20. Ghosh, K., Hawdon, J. & Hotez, P. Vaccination with alum-precipitated recombinant Ancylostoma-secreted protein 1 protects mice against challenge infections with infective hookworm (Ancylostoma caninum) larvae. J Infect Dis 174, 1380-3 (1996). 21. Goud, G. N. et al. Cloning, Yeast Expression, Isolation and Vaccine Testing of Recombinant Ancylostoma secreted protein 1 (ASP-1) and ASP-2 from Ancylostoma ceylanicum. J Infect Dis in press (2003). 22. Henriksen, A. et al. Major venom allergen of yellow jackets, Ves v 5: structural characterization of a pathogenesis-related protein superfamily. Proteins 45, 438-48 (2001). 23. Geldhof, P. et al. Activation-associated secreted proteins are the most abundant antigens in a host protective fraction from Ostertagia ostertagi. Mol Biochem Parasitol 128, 111-4 (2003). 24. Sharp, P. & Wagland, B. M. Nematode Vaccine. (Biotech Australia Pty Limited, USA, 1998). 25. Zhan, B. et al. Molecular characterisation of the Ancylostoma-secreted protein family from the adult stage of Ancylostoma caninum. Int J Parasitol 33, 897-907 (2003). 26. Lustigman, S., James, E. R., Tawe, W. & Abraham, D. Towards a recombinant antigen vaccine against Onchocerca volvulus. Trends Parasitol 18, 135-41 (2002). 27. Lustigman, S., MacDonald, A. J. & Abraham, D. CD4+-dependent immunity to Onchocerca volvulus third-stage larvae in humans and the mouse vaccination model: common ground and distinctions. Int J Parasitol 33, 1161-71 (2003). 28. Murray, J., Gregory, W. F., Gomez-Escobar, N., Atmadja, A. K. & Maizels, R. M. Expression and immune recognition of Brugia malayi VAL-1, a homologue of vespid venom allergens and Ancylostoma secreted proteins. Mol Biochem Parasitol 118, 89-96 (2001). 29. Moyle, M. et al. A hookworm glycoprotein that inhibits neutrophil function is a ligand of the integrin CD11b/CD18. J. Biol. Chem. 269, 10008-15 (1994). 30. Del Valle, A., Jones, B. F., Harrison, L. M., Chadderdon, R. C. & Cappello, M. Isolation and molecular cloning of a secreted hookworm platelet inhibitor from adult Ancylostoma caninum. Mol Biochem Parasitol 129, 167-77 (2003). 31. Hawdon, J. M. & Hotez, P. J. Hookworm: developmental biology of the infectious process. Curr Opin Genet Dev 6, 618-23 (1996). 32. Miller, T. A. Comparison of the immunogenic efficiencies of normal and x-irradiated Ancylostoma caninum larvae in dogs. J Parasitol 52, 512-9 (1966).26 33. Stoltzfus, R. J., Dreyfuss, M. L., Chwaya, H. M. & Albonico, M. Hookworm control as a strategy to prevent iron deficiency. Nutr Rev 55, 223-32 (1997). 34. Hotez, P. J. et al. Current concepts: Hookworm infection. New Eng J Med in press(2004). 35. Stoltzfus, R. J. et al. Epidemiology of iron deficiency anemia in Zanzibari schoolchildren: the importance of hookworms. Am J Clin Nutr 65, 153-9 (1997). 36. Hotez, P. J. et al. Progress in the development of a recombinant vaccine for human hookworm disease: The Human Hookworm Vaccine Initiative. Int J Parasitol 33, 1245-58 (2003). 37. Loukas, A. et al. Vaccination of dogs with a recombinant cysteine protease from the intestine of canine hookworms diminishes fecundity and growth of worms. J Infect Dis in press(2004). 38. Williamson, A. L., Brindley, P. J., Knox, D. P., Hotez, P. J. & Loukas, A. Digestive proteases of blood-feeding nematodes. Trends Parasitol 19, 417-23 (2003). 39. Pawlowski, Z., Karlewiczowa, R. & Rauhut, W. Usefulness of the Harada-Mori and Dancescu methods in diagnosing hookworm infections. Wiad Parazytol 17, 59-63 (1971). 40. Bethony, J. et al. Familial resemblance in humoral immune response to defined and crude Schistosoma mansoni antigens in an endemic area in Brazil. J Infect Dis 180, 1665-73 (1999). 41. Zhan, B., Hotez, P. J., Wang, Y. & Hawdon, J. M. A developmentally regulated metalloprotease secreted by host-stimulated Ancylostoma caninum third-stage infective larvae is a member of the astacin family of proteases. Mol Biochem Parasitol 120, 291-6 (2002). 42. Loukas, A., Croese, J., Opdebeeck, J. & Prociv, P. Detection of antibodies to secretions of Ancylostoma caninum in human eosinophilic enteritis. Trans R Soc Trop Med Hyg 86, 650-3 (1992). 43. Carr, A. & Pritchard, D. I. Antigen expression during development of the human hookworm, Necator americanus (Nematoda). Parasite Immunol 9, 219-34 (1987). 44. Stoute, J. A. et al. A preliminary evaluation of a recombinant circumsporozoite protein vaccine against Plasmodium falciparum malaria. RTS,S Malaria Vaccine Evaluation Group. N Engl J Med 336, 86-91 (1997). 45. Zhan, B., Li, T., Xiao, S., Zheng, F. & Hawdon, J. M. Species-specific identification of human hookworms by PCR of the mitochondrial cytochrome oxidase I gene. J Parasitol 87, 1227-9 (2001). 46. Williamson, A. L. et al. Hookworm aspartic protease, Na-APR-2, cleaves human hemoglobin and serum proteins in a host-specific fashion. J Infect Dis 187, 484-94 (2003). Example 13 Vaccination of Dogs with a Recombinant Cysteine Protease from the Intestine of Canine Hookworms Diminishes Fecundity and Growth of Worms Hookworms digest blood-derived hemoglobin using a range of mechanistically distinct proteases, and preliminary data suggested that Ac-CP-2, a cathepsin B cysteine protease [6] from A. caninum might be involved in this pathway [15]. With a view to eventually vaccinating people against human hookworm disease, we decided to immunize dogs against the canine hookworm, A. caninum, with catalytically active recombinant Ac-CP-2 to determine whether vaccinated animals were protected against hookworm disease. We show that the cathepsin B-like protease, Ac-CP-2 is secreted as a proteolytically active enzyme by the yeast Pichia pastoris and that the enzyme is expressed in the intestinal lumen of blood-feeding adult hookworm parasites. Vaccination of dogs with Ac-CP-2 formulated with several discrete adjuvants resulted in reduced fecal egg counts and decreased sizes of female and male worms. Moreover, the number of female hookworms present in the intestines of vaccinated dogs was significantly reduced relative to control dogs. Antibodies generated by vaccinated dogs bound to the intestinal lumen and intestinal contents of hookworms recovered from those dogs, and interfered with proteolytic function of the recombinant Ac-CP-2 enzyme in vitro. Materials and Methods for Example 13. Expression of Recombinant Ac-CP-2 in Pichia Pastoris The entire open reading frame encoding the pro-enzyme of Ac-CP-2 (spanning Ala-12 to the C-terminal Val-340) excluding the predicted signal peptide was cloned into the expression vector pPIC-Zα using the XbaI and XhoI sites. Colonies were selected from transformed cells and suspension cultures were grown in flasks then transferred to a Bioflo 3000 fermentor (New Brunswick Scientific) utilizing a 5 liter vessel as described [1]. The recombinant protein was secreted into culture medium and affinity purified on nickel-agarose as described [1]. Assessment of Catalytic Activity and Glycosylation of Recombinant Ac-CP-2 Purified, recombinant Ac-CP-2 was assessed for proteolytic activity using the fluorogenic peptidyl substrate Z-Phe-Arg-aminomethyl coumarin (AMC) (Bachem) [2]. The pH optimum of Ac-CP-2 was assessed using Z-Phe-Arg-AMC at different pH values according to published protocols [3]. The cysteine protease inhibitor E64 was included in some assays at a final concentration of 5 μM. Recombinant Ac-CP-2 was treated with PNGase F and O-glycosidase, according to the manufacturer's instructions (Enzymatic CarboRelease kit, QA-Bio), under denaturing conditions to remove any N-linked and O-linked oligosaccharides. Animal Husbandry and Vaccination Purpose-bred, parasite naïve, male beagles aged 8±1 wk were purchased from Marshall farms, identified by ear tattoo, and maintained in the George Washington University Animal Research Facility as previously described [4]. The experiments were conducted according to a protocol approved by the University Animal Care and Use Committee. Before the first vaccination and after each subsequent one, a serum sample was obtained from each dog. Vaccine Study Design and Antigen-Adjuvant Formulation The vaccine trial was designed to test Ac-CP-2 formulated with 4 different adjuvants. ASO3 and ASO2 were obtained from GlaxoSmithKline and ISA 70 was obtained from SEPPIC, Inc. Alum was prepared as described [5]. To make six doses of Ac-CP-2 formulated with ASO3, 600 μg of recombinant protein (0.3 ml of Ac-CP-2 at a concentration of 2 mg.ml−1) was mixed with 1.2 ml of 20 mM Tris-HCl, 0.5 M NaCl, pH 7.9 and 1.5 ml of ASO3; the contents of the tube were vortex mixed for 30 seconds then shaken at low speed for 10 minutes. Dogs were immunized with 100 μg of formulated antigen in a final volume of 0.5 ml. To make six doses of Ac-CP-2 formulated with AS02, 600 μg of recombinant protein (0.3 ml of Ac-CP-2 at a concentration of 2 mg.ml−1) was mixed with 0.9 ml of 20 mM Tris-HCl, 0.5 M NaCl, pH 7.9 and 1.8 ml of ASO2; the contents of the tube were vortex mixed for 30 seconds then shaken at low speed for 10 minutes. Dogs were immunized with 100 μg of formulated antigen in a final volume of 0.5 ml. To make six doses of Ac-CP-2 formulated with ISA 70, 600 μg of recombinant protein (0.3 ml of Ac-CP-2 at a concentration of 2 mg.ml−1) was mixed with 1.66 ml of ISA 70; the contents of the tube were vortex mixed for 30 seconds then shaken at low speed for 10 minutes. Dogs were immunized with 100 μg of formulated antigen in a final volume of 0.327 ml. To make six doses of Ac-CP-2 formulated with alum, 600 μg of recombinant protein (0.3 ml of Ac-CP-2 at a concentration of 2 mg.ml−1) was mixed with 0.135 ml of 1M NaHCO3; 0.3 ml of AIK(SO4)2 12H2O [5] was added to initiate precipitation. Precipitate was collected by centrifugation at 14,000 rpm for 10 mins. The supernatant was collected and the precipitation was repeated; the supernatant was collected and assayed for non-precipitated protein using a BCA protein assay (Pearce). The two precipitates were pooled, washed with PBS and resuspended in 3 ml of the supernatant and dogs were immunized with 100 μg of formulated antigen in a final volume of 0.5 ml. Alum only control was prepared as described above, with PBS included instead of Ac-CP-2. Canine Immunizations and Antibody Measurements Beagles were immunized with formulated Ac-CP-2 as previously described [4]. The study regimen used is shown along the X-axis of FIG. 2. The vaccines were administered intramuscularly three times beginning at age 62+/−4 days. Boosts were administered to the dogs at intervals of 21 days. Blood was drawn at least once every 21 days and serum was separated from cells by centrifugation. Enzyme-linked immunosorbent assays (ELISA) were performed as previously described [4]. Recombinant Ac-CP-2 was coated onto microtiter plates at a concentration of μg.ml−1. Dog sera were titrated between 1:100 and 1:2×10 6 to determine endpoint titers. Anti-canine IgG1, IgG2 and IgE antibodies conjugated to horse-radish peroxidase (Bethyl Laboratories) were used at a dilution of 1: 1,000. Hookworm Infections and Parasite Recovery Fourteen-sixteen days after the final immunization, dogs were anaesthetized using a combination of ketamine and xylazine (20 mg/kg and 10 mg/kg respectively) and 500 A. caninum L3 in a final volume of 50 μL were applied to the footpad. After applying L3, the foot was wrapped in parafilm, gauze padding and packaging tape in that order to ensure that L3 did not escape from the site of application. Dogs were monitored for 3 hours after which the parafilm, gauze and tape were removed. The site of L3 application was rinsed with saline and any remaining L3 that had not penetrated were counted. Quantitative hookworm egg counts (McMaster technique) were obtained for each dog 3 days per week beginning on day 13-15 post-infection. Four weeks post-infection, the dogs were killed by intravenous injection of barbiturate, and adult hookworms were recovered and counted from the small and large intestines at necropsy [4]. The sex of each adult worm was determined and worm lengths were measured as described elsewhere [6]. Approximately 1-2 cm lengths of the small intestine were removed and stored in formalin for future histopathological analysis. Statistical Methods The percentage reduction or increase in adult hookworm burden in the vaccinated groups was expressed relative to the control group as described elsewhere [4]. The statistical significance of differences in adult hookworm burdens was determined using nonparametric tests: the Kruskal-Wallis test with Dunn procedures, and Mann-Whitney U-tests. Differences between groups in quantitative hookworm egg counts and worm lengths were assessed by the ANOVA test. Once determined the differences among the means of groups were determined, a Dunnet post hoc multiple comparison t test was used to compare the vaccine treatment groups against the control group. The sex differences of the adult hookworms recovered were statistically compared using the Wilcoxon-Signed Ranks test for 2 dependent groups. Differences were considered statistically significant if the calculated P value was equal to or less than 0.10 (2-sided) or −0.05 (1-sided). Immunohistochemistry Adult hookworms recovered from vaccinated dogs were fixed, sectioned and probed with various sera and Cy3-conjugated secondary antibodies (BD Biosciences) as previously described [7]. Sera from vaccinated dogs and Cy3-conjugated anti-dog IgG were diluted 1:500. Some sections were probed with rabbit anti-Ac-CP-1 serum [6] followed by Cy3-conjugated anti-rabbit IgG; both antibodies were diluted 1:500. Effect of Anti-Ac-CP-2 IgG on Proteolytic Activity Canine IgG was purified from sera of vaccinated dogs using protein A-agarose (Amersham Biosciences) as previously described [8]. Purified IgG (10-500 ng) was incubated with 1.0 μg of recombinant Ac-CP-2 for 45 mins prior to assessing proteolytic activity as described above. Results for Example 13. Secretion of Catalytically Active, Glycosylated Ac-CP-2 by P. Pastoris Ac-cp-2 cDNA (GenBank accession number U18912) was cloned and reported by Harrop and colleagues [6]. We expressed recombinant Ac-CP-2 as a secreted fusion protein in P. pastoris with a yield of 35 mg.L−1. Secretion was mediated by the α-mating factor signal peptide derived from the pPIC-Zα vector. The protein was purified from P. pastoris culture supernatant using nickel-agarose [20]. The purified protein migrated with an apparent molecular size of 48 kDa (not shown). This was higher than the predicted size of the pro-enzyme (41.8 kDa) and processed, mature enzyme (32.1 kDa) factoring in the C-terminal myc and His tags and—terminal EAEAEF motifs (introduced by the choice of restriction sites used in cloning of the construct). N-linked glycosylation of the 5 predicted sites in Ac-CP-2 probably accounted for some of the discrepancy between the predicted and observed molecular sizes. Deglycosylation with PNGaseF reduced the apparent molecular mass of recombinant Ac-CP-2 by 5-10 kDa although numerous bands within this size range were apparent (not shown), probably corresponding to partially deglycosylated proteins. N-terminal amino acid sequencing of the major secreted protein by Edman degradation showed the N-terminal residue to be Glu-13, suggesting that some post-translational processing of the pro-region had occurred. However, this did not correspond with the predicted cleavage site of the pro-region from the mature enzyme (Asp-81-Asp-82 using the numbering scheme of the fusion protein presented here). Although this is only a predicted cleavage site based on the known cleavage site of the pro-region of other related enzymes [9], it is unlikely that Glu-13 is the N-terminal residue of the native, secreted protease. Difficulty in obtaining sufficient quantities of native, hookworm-derived Ac-CP-2 precluded N-terminal sequence information for comparison. Nonetheless, numerous faint bands with molecular sizes ranging from 30-40 kDa appeared when the purified recombinant Ac-CP-2 was stained with silver (not shown), suggesting that a small quantity of the recombinant protein was correctly processed to yield the mature form of the enzyme. This was further confirmed by the catalytic activity seen when recombinant Ac-CP-2 was incubated with Z-Phe-Arg-AMC (FIG. 51). A broad pH range was observed with activity detected between pH 4-8 with optimal catalysis between pH 5 and pH 7. Addition of the cysteine protease inhibitor, E64, to a final concentration of 5 μM completely ablated cleavage of the peptide substrate (not shown). Moreover, other recombinant proteins (non-proteolytic) expressed and purified in an identical fashion in our laboratory did not cleave Z-Phe-Arg-AMC (not shown). Recombinant Ac-CP-2 is Immunogenic in Dogs Dogs immunized with recombinant Ac-CP-2 formulated with different adjuvants produced IgG1 and IgG2 antibody responses as measured by ELISA using the recombinant protein (FIG. 52). IgE titers were low (<1,500) and are not discussed further. The maximum IgG1 titers (geometric mean=50,452) were induced by formulating Ac-CP-2 with AS03. The maximum IgG2 titers (geometric mean=78,294) were induced by formulating Ac-CP-2 with AS02. Dogs immunized with adjuvant alone did not generate detectable immune responses until larval challenge, suggesting that antibodies to Ac-CP-2 (or a similar protease) are induced during natural infection with the parasite. Ac-cp-2 mRNA was not identified from more than 9,000 expressed sequence tags generated from serum-stimulated (induced to feed) A. caninum L3 implying that the mRNA and protein are only expressed in the adult-blood feedingstages. The increase in anti-Ac-CP-2 antibody titers in control dogs after L3 challenge (but before worms would have matured to adulthood) is likely due to secretion of antigenically related cysteine proteases by L3; the closest homolog of Ac-CP-2 from A. caninum L3 cDNAs (EST pb58a11.yl) shared 64% identity at the amino acid level. ASO2 and ASO3 adjuvants induced the greatest antibody responses, especially of the IgG2 subclass. ISA 70 and alum induced much weaker responses although the general pattern and duration of responses were similar to those induced by the ASO adjuvants. Vaccination with Ac-CP-2 Decreases Fecundity of Female Hookworms Dogs rapidly develop age- and exposure-related immunity to A. caninum [10]. We therefore observed egg counts from vaccinated animals up to 3 weeks post-challenge. At 3 weeks after larval challenge, a significant decrease in egg counts was observed in dogs vaccinated with Ac-CP-2 formulated with either ASO2, ASO3 or alum compared with dogs that were vaccinated with alum alone (P≦0.05) (FIG. 53). Statistically significant differences between mean adult male worm burdens of dogs vaccinated with Ac-CP-2 and adjuvant alone were not seen (Table X). The greatest number of female worms was recovered from dogs immunized with alum alone (mean=131); the smallest number of female worms was recovered from dogs immunized with Ac-CP-2/ASO3 (mean=104). While the decrease in worm burdens in the latter group was noteworthy, the differences were not statistically significant. TABLE X Mean adult worm numbers recovered from the small and large intestines of dogs immunized with Ac-CP-2 formulated with different adjuvants or adjuvant alone. Small intestine Large intestine Group Male Female Male Female Ac-CP-2/ASO3 107 111 8 9 Ac-CP-2/ASO2 109 104 7 11 Ac-CP-2/ISA70 113 116 7 8 Ac-CP-2/alum 125 120 4 6 Alum 105 131 6 9 Vaccination with Ac-CP-2/ASO2 Resulted in a Lower Proportion of Female Worms Comparison of the proportions of male to female worms revealed that worms recovered from dogs vaccinated with Ac-CP-2/alum (P=0.05) and Ac-CP-2/ASO2 (P=0.074) had more male worms than female worms when compared with worms recovered from dogs immunized with adjuvant alone (FIG. 54). Vaccination with Ac-CP-2 Protease Stunts the Growth of Hookworms At necropsy, all worms recovered from the vaccinated dogs were fixed in formalin. The lengths of 100 undamaged worms from each group were measured, and the mean lengths compared statistically. The mean lengths of female worms recovered from dogs vaccinated with Ac-CP-2/ASO2 (P=0.003) and Ac-CP-2/ASO3 (P=0.033) were shorter than that of worms recovered from dogs immunized with adjuvant alone (Table XI). Statistically significant differences in male worm lengths were obtained when male worms from dogs that received Ac-CP-2/AS03 were compared with worms recovered from dogs immunized with alum alone (P=0.035). TABLE XI Adult hookworms recovered from dogs that were vaccinated with Ac-CP-2 were shorter than those recovered from dogs immunized with adjuvant alone. P values compare the difference between each group that received the vaccine and the adjuvant alone group. N = number of worms measured. mean length Group N (cm) SD P value* Ac-CP-2/ASO3 Female 100 0.534 0.22 0.033 Male 100 0.384 0.11 0.035 Ac-CP-2/ASO2 Female 100 0.507 0.22 0.003 Male 100 0.432 0.12 0.844 Ac-CP-2/ISA70 Female 100 0.572 0.21 0.567 Male 100 0.465 0.14 0.999 Ac-CP-2/Alum Female 100 0.558 0.24 0.567 Male 100 0.471 0.14 1.000 Alum only Female 100 0.612 0.28 — Male 100 0.430 0.13 — SD, standard deviation from mean. *indicates P-value for Dunnett t-tests in which one group is treated as a control and the test groups are compared against it. Anti-Ac-CP-2 Antibodies are Ingested by and Bind to the Intestine of Feeding Hookworms The site of anatomical expression of Ac-CP-2 within adult hookworms had not been previously reported. We therefore used sera from dogs immunized with Ac-CP-2/ASO3 to localize expression to the brush border membrane of the intestine of adult worms (not shown). Ac-CP-1 on the other hand was shown by Harrop et al. [6] and confirmed by us here (not shown) to be expressed in the cephalic and excretory glands of the parasite, accounting for its presence in excretory/secretory products of adult A. caninum [6]. To determine whether vaccination of dogs induced circulating antibodies that bound to the intestinal lumen during infection, parasites were removed from vaccinated dogs, fixed, sectioned and probed with secondary antibody (anti-dog IgG conjugated to Cy3) only. Worms recovered from dogs immunized with Ac-CP-2 (not shown) but not from dogs immunized with adjuvant alone (not shown) contained antibodies that were ingested with the blood-meal of the worm, and subsequently bound specifically to the intestine and intestinal contents. IgG from Dogs Vaccinated with Ac-CP-2 Neutralizes Proteolytic Activity In Vitro Purified IgG from dogs that were immunized with Ac-CP-2 was effective at neutralizing the catalytic activity of Ac-CP-2. Incubation of 50 ng of pooled IgG from dogs immunized with Ac-CP-2/ASO3 resulted in a 73% reduction in the cleavage of Z-Phe-Arg-AMC by 1.0 μg of Ac-CP-2 (Table XII). Fifty nanograms of IgG from dogs immunized with adjuvant alone resulted in a 3% reduction in proteolytic activity, implying that vaccination with Ac-CP-2 resulted in the production of antibodies that neutralized the function of the enzyme in vivo. TABLE XII Effect of pooled IgGs from vaccinated (Ac-CP-2/ASO3) and control (adjuvant alone) dogs on the proteolytic activity of recombinant Ac-CP-2 against the substrate Z-Phe-Arg-AMC. Values are expressed as mean percent reductions in proteolytic activity from triplicate experiments. Ac-CP-2 Ac-CP-2 + Ac-CP-2 + Treatment only αCP-2 IgG norm IgG Ac-CP-2 + E64 % reduction in 0 ± 0 73 ± 3 3 ± 2 100 ± 0 proteolytic activity Discussion for Example 13. Here we describe vaccination of dogs with a recombinant cysteine protease that resulted in partial protection as measured by reduced fecal egg counts, stunting of adult worms, decreased proportion of female to male worms and the generation of protease-neutralizing antibodies that bind to the hookworm intestine in vivo. In the 1930's, the late Asa Chandler hypothesized that antibodies directed against critical parasite enzymes mediated a successful anti-helminthic immune response by preventing worms from digesting host proteins [11]. This is the first report of protective efficacy with a recombinant protease from a parasitic nematode, and provides support for Chandler's anti-enzyme theory. Although secreted by P. pastoris, complete processing of recombinant Ac-CP-2 to yield a mature enzyme did not occur; nonetheless, proteolytic activity was detected in the purified protein. P. pastoris transformed with a cDNA encoding F. hepatica cathepsin L secrete a partially activated protease that also exhibits catalytic activity, however unlike Ac-CP-2, this enzyme completely auto-activated after 2 hours at pH 5.5 [12]. Ac-CP-2 displayed a broad pH range with optimal activity at pH 5-7, supporting earlier work that described an optimal pH range of 5-9 for ES products and somatic extracts of adult A. caninum using Z-Phe-Arg-AMC [3]. Hematophagous helminths require blood as a source of nutrients to mature and reproduce. Female schistosomes ingest 13 times as many erythrocytes and ingest them about nine times faster than male worms [13]. Moreover, mRNAs encoding hemoglobin-degrading proteases of schistosomes are over-expressed in female worms [14]. While similar studies have yet to be performed for hookworms, female hookworms are bigger than males and lay up to 10,000 eggs per day, implying that they have a greater metabolism and therefore demand for erythrocytes. Ac-CP-2 is expressed in the gut, and preliminary data described elsewhere [15] have shown that the enzyme is involved in hemoglobinolysis in the hookworm intestine. It is therefore not surprising that interruption of the function of Ac-CP-2 via the action of neutralizing antibodies had a deleterious effect on the growth of female worms and subsequent egg production. Vaccination of livestock and laboratory animals with cysteine proteases of other nematodes as well as trematodes has resulted in anti-fecundity/anti-embryonation effects. Immunization of sheep with the intestinal brush border complex, H-gal-GP, confers high levels of protection (both anti-parasite and anti-fecundity) against H. contortus and at least three different protease activities, including cathepsin B cysteine proteases, have been detected in this extract. Immunisation of sheep with a cysteine protease-enriched fraction of H. contortus membranes resulted in 47% protection against adult worms and 77% reduction in faecal egg output [15]. To date, the success obtained in vaccinated laboratory animals with cysteine proteases purified from parasite extracts has not been reproduced with the corresponding recombinant proteins expressed in Escherichia coli presumably because the recombinant molecules are incorrectly folded (and catalytically inactive) and thereby fail to induce responses capable of inactivating native proteases [16]. Cysteine Proteases are also Efficacious as Anti-Trematode Vaccines. Vaccination of cattle with cathepsin L cysteine proteases of F. hepatica results in decreased embryonation and hatch rates of eggs in addition to decreased worm burdens [12]. While these studies were performed with native proteins, trials with yeast-expressed recombinant proteases are in progress [12]. Vaccine trials using a DNA construct for S. mansoni Sm32, an asparaginyl endopeptidase that is cysteine protease-like in function but unrelated in sequence to cathepsins L and B, induced an anti-fecundity effect in a murine model of schistosomiasis when administered as a DNA construct [17]. We recently described partial protection of hamsters against another hookworm, Ancylostoma ceylanicum, by immunization with a larval antigen, Ay-ASP-2, as a model of human hookworm disease [1]. The orthologous protein from A. caninum, Ac-ASP-2, is expressed by the L3 stage of the parasite when it is stimulated to feed in vitro [18]. Vaccination with ASP-2 resulted in a 32% reduction in the number of worms that reached adulthood [1], and we envisage that a human hookworm vaccine would ultimately consist of multiple antigens targeting both the L3 and the blood-feeding adult-stage. The data presented here suggest that cysteine proteases lining the intestinal lumen of hookworms are a valid target in the design of vaccines against hookworm disease. We have identified other proteases of different mechanistic classes that line the intestinal brush border of adult hookworms where they digest host hemoglobin [7, 8, 15], and some of these molecules might also prove efficacious as recombinant vaccines against hookworm infection. References for Example 13 1. Goud G N, Zhan B, Ghosh K, et al. Cloning, Yeast Expression, Isolation and Vaccine Testing of Recombinant Ancylostoma secreted protein 1 (ASP-1) and ASP-2 from Ancylostoma ceylanicum. J Infect Dis 2003; in press 2. Loukas A, Selzer P M and Maizels R M. Characterisation of Tc-cpl-1, a cathepsin L-like cysteine protease from Toxocara canis infective larvae. Mol Biochem Parasitol 1998;92:275-89 3. Dowd A J, Dalton J P, Loukas A C, Prociv P and Brindley P J. Secretion of cysteine proteinase activity by the zoonotic hookworm Ancylostoma caninum. Am J Trop Med Hyg 1994;51:341-7 4. Hotez P J, Ashcom J, Bin Z, et al. Effect of vaccinations with recombinant fusion proteins on Ancylostoma caninum habitat selection in the canine intestine. J Parasitol 2002;88:684-90 5. Ghosh K, Hotez P J. Antibody-dependent reductions in mouse hookworm burden after vaccination with Ancylostoma caninum secreted protein 1. J Infect Dis 1999; 180:1674-81 6. Harrop S A, Sawangjaroen N, Prociv P and Brindley P J. Characterization and localization of cathepsin B proteinases expressed by adult Ancylostoma caninum hookworms. Mol Biochem Parasitol 1995;71:163-71 7. Williamson A L, Brindley P J, Abbenante G, et al. Hookworm aspartic protease, Na-APR-2, cleaves human hemoglobin and serum proteins in a host-specific fashion. J Infect Dis 2003; 187:484-94 8. Williamson A L, Brindley P J, Abbenante G, et al. Cleavage of hemoglobin by hookworm cathepsin D aspartic proteases and its potential contribution to host specificity. FASEB J 2002;16:1458-60 9. Tort J, Brindley P J, Knox D, Wolfe K H and Dalton J P. Proteinases and associated genes of parasitic helminths. Adv Parasitol 1999;43:161-266 10. Miller T A. Influence of age and sex on susceptibility of dogs to primary infection with Ancylostoma caninum. J. Parasitol. 1965;51:701-4 11. Chandler A C. Susceptibility and resistance to helminthic infections. J Parasitol 1932;3:135-52 12. Dalton J P, Neill S O, Stack C, et al. Fasciola hepatica cathepsin L-like proteases: biology, function, and potential in the development of first generation liver fluke vaccines. Int J Parasitol 2003;33:1173-81 13. Hota-Mitchell S, Siddiqui A A, Dekaban G A, Smith J, Tognon C and Podesta R B. Protection against Schistosoma mansoni infection with a recombinant baculovirus-expressed subunit of calpain. Vaccine 1997; 15:1631-40 14. Hu W, Yan Q, Shen D K, et al. Evolutionary and biomedical implications of a Schistosoma japonicum complementary DNA resource. Nature Genet 2003;35:139-147 15. Knox D P, Smith S K and Smith W D. Immunization with an affinity purified protein extract from the adult parasite protects lambs against infection with Haemonchus contortus. Parasite Immunol 1999;21:201-10 16. Dalton J P, Brindley P J, Knox D P, et al. Helminth vaccines: from mining genomic information for vaccine targets to systems used for protein expression. Int J Parasitol 2003;33:621-40 17. Chlichlia K, Bahgat M, Ruppel A and Schirrmacher V. DNA vaccination with asparaginyl endopeptidase (Sm32) from the parasite Schistosoma mansoni: anti-fecundity effect induced in mice. Vaccine 2001;20:439-47 18. Hawdon J M, Narasimhan S and Hotez P J. Ancylostoma secreted protein 2: cloning and characterization of a second member of a family of nematode secreted proteins from Ancylostoma caninum. Mol Biochem Parasitol 1999;99: 149-65 Example 14 Canine Vaccine Trial with Antigens Ac-ASP-2, Ac-MEP-1, Ac-APR-1, and Ac-API A canine vaccine trial was carried out to examine the protective efficacy of four antigens formulated with the adjuvant, ASO3. These antigens are Ac-ASP-2, Ac-MEP-1, Ac-APR-1, and Ac-API. The trial confirmed our earlier findings that ASP-2 is a promising vaccine antigen (based on both human serology and hamster animal trials). This was evidenced by reduction in worm number, worm size, and fecal egg counts. The trial also provided preliminary data that APR-1 and MEP-1 also offer promise as protective antigens. Experimental Design and Methods Vaccine Study Design and Antigen-Adjuvant Formulation The vaccine trial was designed to test Ac-API, Ac-ASP-2, Ac-MEP-1, Ac-APR-1 formulated with Adjuvant System 03 (AS03) obtained from GlaxoSmithKline (GSK). The rationale for selecting AS03 as an adjuvants is discussed elsewhere (Stoute et al, 1997). The ten purpose bred beagles were randomized into five arms: immunized with the adjuvant-formulated recombinant proteins or adjuvant only (control). To make six doses of antigen formulated with AS03, 600 g of recombinant protein (0.3 ml of antigen at a concentration of 2 mg.ml−1) was mixed with 1.2 ml of 20 mM Tris-HCl, 0.5 M NaCl, pH 7.9 and 1.5 ml of AS03; the contents of the tube were vortex mixed for 30 seconds then shaken at low speed for 10 minutes. Dogs were immunized with 100 g of formulated antigen in a final volume of 0.5 ml. ASO3 only control was prepared as described above, with PBS included instead of antigen. Formulation of GSK adjuvants were conducted according to the protocol provided by GSK. All injections were performed intramuscularly (IM). Test and control articles were prepared on the day of injection. All animals received 4 immunizations approximately 3 weeks apart. Hookworm Infections and Parasite Recovery A. caninum larvae were cultured from eggs collected in the feces of infected dogs. All hookworms in the infective challenge were approximately equal age (17±7 days post hatching). The species identity of the infective larvae were validated using PCR. All dogs were infected by the footpad method with the same dose of 500 L3 of A. caninum (Zhan et al, 2001). Larval challenge occurred on one of three consecutive days (at age 120+/−9 days). Fourteen-sixteen days after the final immunization, dogs were anaesthetized using a combination of ketamine and xylazine (20 mg.kg−1 and 10 mg.kg−1 respectively), and 500 A. caninum L3 in a final volume of 50 l were applied to the footpad. Canine Immunizations and Antibody Measurements Beagles were immunized with formulated Ac-ASP-2 as previously described (Loukas et al, 2004). The vaccines were administered IM three times beginning at age 62+/−4 days. Boosts were administered to the dogs at intervals of 21 days. Blood was drawn at least once every 21 days and serum was separated from cells by centrifugation. Each animal's specific antibody response was evaluated by indirect ELISA using serum taken prior to the infective challenge (Loukas et al, 2004). Recombinant Ac-ASP-2 was coated onto microtiter plates at a concentration of 5 g.ml−1. Dog sera were titrated between 1:100 and 1:2×106 to determine endpoint titers. Anti-canine IgG1, IgG2 and IgE antibodies conjugated to horse-radish peroxidase (Bethyl Laboratories) were used at a dilution of 1:1,000. L3 Skin Penetration Assays Live A. caninum L3 were incubated with sera (neat) from immunized dogs then L3 were placed on canine skin to observe whether serum antibodies interfered with the penetration of skin in vitro (Williamson et al, 2003). Briefly, fresh skin from the ear of a dog was shaved, and approx. 4 cm2 section of skin was stretched and sandwiched between 2×20 mL syringe barrels that were clamped together with bulldog clips. The lower syringe was filled to the top with PBS so that the buffer was in contact with the underside of the skin. One milliliter of PBS was placed on the skin for 15 min to check integrity of the skin. L3 (300 L3/group) were then incubated in 0.05 ml of PBS, pH 7.2, or undiluted serum from different vaccinated or control dogs for 30 min at 37 C. Each group of L3 were then placed on the upper side of the skin (added to the 1.0 ml of PBS already present) and allowed to migrate for 30 min at RT. L3 that remained on the surface of the skin were collected and counted, by removing the remaining liquid with a pipette and washing the skin with 2 volumes of PBS. Each assay was performed in triplicate. Expression and Purification of the Recombinant Proteins Ac-ASP-2. The cloning of Ac-ASP-2 is reported elsewhere (Hawdon et al, 1999). Other antigens. Details of the cloning and/or expression of Ac-MEP-1 and Ac-APR-1 are reported elsewhere (Harrop et al, 1996; Brinkworth et al, 2001; Jones and Hotez, 2002; Hotez et al, 2002). Briefly, both of these proteins are hemoglobin-degrading proteasese from the alimentary canal of adult hookworms. Antibody Responses Following Immunization The individual and geometric means of the IgG1, IgG2, and IgE antibody titers are shown in Table XIII. TABLE XIII Pre-challenge antibody titer to recombinant proteins following immunization IgG1 IgG2 IgE Ac-ASP2 A1 13,500 40,500 100 A2 13,500 13,500 100 A3 13,500 13,500 100 A4 13,500 40,500 100 A5 4,500 13,500 100 GEOMEAN 10,837 20,950 100 Ac-API B1 4,500 40,500 N/A B2 4,500 40,500 N/A B3 1,500 40,500 N/A B4 4,500 40,500 N/A B5 4,500 13,500 100 GEOMEAN 3,612 32,511 100 Ac-MEP C1 100 1,500 N/A C2 100 500 N/A C3 100 1,500 N/A C4 N/A 1,500 N/A C5 100 1,500 N/A GEOMEAN 100 1,204 N/A Ac-APR1 D1 N/A 500 N/A D2 100 4,500 N/A D3 N/A 100 N/A D4 N/A 500 N/A D5 N/A 500 N/A GEOMEAN 100 562 N/A The antibody responses to both ASP-2 and API were robust. However, only a single dog developed a substantial antibody titer to APR-1 and the overall antibody response to Ac-MEP-1 was weak. Closer analysis reveals that canines immunized with recombinant Ac-ASP-2/AS03 produced strong IgG1 and IgG2 antibody titers to recombinant Ac-ASP-2. The IgE titers to Ac-ASP-2 in the test canines were one log lower than the IgG1 and IgG2 titers. Dogs immunized with AS03 adjuvant alone did not generate detectable antibody responses to Ac-ASP-2 prior to larval challenge. Sera from dogs vaccinated with recombinant ASP-2 immunoprecipitated native ASP-2 from biotinylated A. caninum extracts (L3E), while sera from animals immunized with adjuvant alone did not precipitate any L3E proteins. Reductions in Adult Worm Burden Following Vaccination The overall worm burden data in vaccinated vs. control (AS03) dogs is presented in Tables XIV and XV. Briefly, there was good consistency in the number of worms from each group, with the exception of the two hemoglobinase groups. Of all of the groups, the greatest mean worm burden reduction was among the ASP-2-vaccinated dogs, while the greatest median worm burden was in the MEP-1 vaccinated dogs. TABLE XIV Summary results of the worm burdens in vaccinated and control dogs Intestine Colon Male Female Male Female Total A1 107 115 1 3 226 A2 85 72 9 8 174 A3 54 28 1 6 89 A4* 62 87 5 5 160 A5 72 101 4 4 181 Average 76 81 4 5 166 B1 54 86 3 3 146 B2 83 83 0 1 167 B3 80 66 2 12 160 B4 105 91 9 24 229 B5 115 91 10 21 237 Average 87 83 5 12 188 C1 65 64 0 0 129 C2 47 58 1 2 108 C3 131 153 2 7 293 C4 124 130 5 9 268 C5 49 50 8 12 119 Average 87 91 3 6 183 D1 65 76 0 1 168 D2 47 41 11 18 119 D3 131 69 3 3 146 D4 124 87 5 8 202 D5* 49 122 0 0 250 Average 83 79 4 6 177 El 76 59 7 23 165 E2 103 119 1 3 227 E3 87 113 7 8 215 E4 99 82 7 8 196 E5 114 100 1 2 217 Average 96 95 5 9 204 *1 intestinal worm of unknown gender ** 1 colon worm of unknown gender TABLE XV Mean and Medians of the worm burdens in vaccinated dogs relative to control (ASO3) dogs Ac-ASP-2 Valid 5 Mean 166.0000 Median 174.0000 Minimum 89.00 Maximum 226.00 Ac-API 5 Mean 187.800 Median 167.0000 Minimum 146.00 Maximum 237.00 Ac-MEP 5 Mean 183.4000 Median 129.0000 Minimum 109.00 Maximum 293.00 Ac-APR-1 5 Mean 177.0000 Median 168.0000 Minimum 119.00 Maximum 250.00 ASO3 (adjuvant) 5 Mean 203.8000 Median 215.0000 Minimum 165.00 Maximum 226.00 The number of adult hookworms recovered from each of the ASP-2 vaccinated dogs was lower than the mean of the control dogs, with the exception of dog A1. This accounted for the overall mean worm burden reduction. Dog A3 in the ASP-2 group exhibited the greatest worm burden reduction for the entire study (58%). The worm burden reduction is statistically significant if dog A1 is removed (P=0.03). Among the MEP-1 vaccinated dogs, three out of the five exhibited significant protection as evidenced by worm burden reductions that exceeded 36%. However in two of the vaccinated dogs, the number of hookworms recovered exceeded the mean of the control dogs. These findings accounted for the large reduction in median worm burden, but not the mean. Among the APR-1 vaccinated dogs, only dog D2 exhibited a significant reduction in worm burden (42%). Of interest, this was the only dog that acquired significant anti-APR-1 antibody titers following vaccination. There was no remarkable reduction in worm burden following API vaccination. These data are also pictorially represented in FIG. 55. Reduction in Quantitative Egg Counts (QECs) As shown in FIG. 56, there was a significant reduction in fecal eggs (fecundity) for the ASP-2, API, and APR-1 group relative to the control group. Fecal eggs were lowest in the ASP-2 vaccinated dogs. These data indicate that ASP-2 is an immunogenic molecule and a promising protective antigen. In addition, both MEP-1 and APR-1, each a adult hookworm hemoglobinase, show some promise at protection. MEP-1 vaccinations resulted in reduced median hookworm burdens, while in a single dog that developed anti-APR-1 antibody titers there was also a reduction in the number of adult hookworms. However, the overall low antibody titers in response to these molecules suggests that the results of this trial could be improved if the immunogenicity of each hemoglobinase was increased. Studies are underway to re-express the proteases in yeast in an effort to improve immunogenicity. Previously a third hemoglobinase, CP-2, was successfully expressed in yeast, and shown to be immunogenic and protective (Loukas et al, 2004). References Cited for Example 14 Brinkworth, R I, et al. Hemoglobin-degrading aspartic proteases of blood-feeding parasites: substrate specificity revealed by homology models. JBC 276: 38844-51 (2001). Harrop, SA, et al. Acasp, a gene encoding cathepsin D-like aspartic protease from the hookworm Ancylostoma caninum. Biochemical and Biophysical Research Communications 227: 294-302 (1996). Hawdon, J. M., Narasimhan, S. & Hotez, P. J. Ancylostoma secreted protein 2: cloning and characterization of a second member of a family of nematode secreted proteins from Ancylostoma caninum. Mol Biochem Parasitol 99, 149-65 (1999). Hotez, P J, et al. Effect of vaccinations with recombinant fusion proteins on Ancylostoma caninum habitat selection in the canine intestine. J Parasitol. 88: 684-90 (2002) Jones B F, Hotez P J. Molecular cloning and characterization of Ac-mep-1, a developmentally regulated gut luminal metalloendopeptidase from adult Ancylostoma caninum hookworms. Mol Biochem Parasitol 119: 107-16 (2002). Loukas, A. et al. Vaccination of dogs with a recombinant cysteine protease from the intestine of canine hookworms diminishes fecundity and growth of worms. Journal of Infectious Diseases in press (2004). Stoute, J. A. et al. A preliminary evaluation of a recombinant circumsporozoite protein vaccine against Plasmodium falciparum malaria. RTS,S Malaria Vaccine Evaluation Group. N Engl J Med 336, 86-91 (1997). Williamson, A. L. et al. Hookworm aspartic protease, Na-APR-2, cleaves human hemoglobin and serum proteins in a host-specific fashion. J Infect Dis 187, 484-94 (2003). Zhan, B., Li, T., Xiao, S., Zheng, F. & Hawdon, J. M. Species-specific identification of human hookworms by PCR of the mitochondrial cytochrome oxidase I gene. J Parasitol 87, 1227-9 (2001). Example 15 Cloning, Transformation and Expression in Pichia Pastoris of Na-asp-2 The purpose of this study was to identify the major orthologue of Ac-asp-2 (Hawdon et al, 1999) from Necator americanus. To identify the orthologue, a cDNA library was prepared as described in a research report published in the Chinese Journal of parasitology and Parasitic Diseases (Zhan et al, 2000). Briefly, these L3 were obtained from hamsters infected with Necator americanus as described (Xue et al, 2003). The L3 have now gone through approximately 100 passages through hamsters, but were originally derived by coproculture from an N. americanus infected individual from Hunan Province (Xue et al, 2003). From 500,000 plaques screened using Ac-asp-2 cDNA, only 2 positive clones were obtained. These two positive clones were subjected to DNA sequencing. Neither of these clones contained the full-length signal peptide. Based on the sequence obtained, forward and reverse primers were selected (both with and without histag, and all with EAEAEF vector sequence) and synthesized (Integrated DNA Technologies, Inc., Coralville, IA). These primers were used to amplify Na-asp-2 cDNA from the 1st strand Na-L3 cDNA. Na-L3 cDNA from mRNA extracted from L3 as described previously (Zhan et al, 2000). The L3 were obtained from golden hamsters infected with N. americanus as described previously (Xue et al, 2003). The PCR products were ligated into pPICZ A using EcoR1 and Xba1 sites. The ligation product was transformed into E. coli DH5 competent-rendered cells and the recombinants were selected by growing on LB-Zeocin plates. Eight colonies were picked from each transformation (with and without histag) and analyzed by PCR with vector primers. Each of the positive clones contained an insert of the predicted size. From two clones (one with histag and the other without) the plasmid was extracted and sent for DNA Sequencing (Nevada Genomics Center). The clones obtained did not contain the 5′ end of the Na-asp-2 cDNA, which encoded the N-terminus of the full signal peptide. Therefore, concurrent with the amplification of Na-asp-2 cDNA from L3 it was of additional interest to unambiguously determine the 5′ end of the full length clone. 5′ RACE was conducted to obtained a full-length cDNA. This was done using the Gene Racer Kit from Invitrogen. Reverse primers for 5′RACE were selected from a portion of the cDNA encoding the C-terminus of Na-ASP-2. The primers were synthesized by IDT (Integrated DNA Technologies, inc., Coralville, IA). The 5′ RACE clones were sequenced. Rescreening: The purpose of rescreening was to make certain that there were no other major orthologues cDNAs to Ac-asp-2 (SEQ ID NO: 19). We wished to make certain that our clone represented the only Necator ASP-2 found in L3. To conduct this work, two fragments of Ac-asp-2 (SEQ ID NO: 19) cDNA were selected as probes based on the most conserved areas compared with asp-2 from other species of hookworm. On this basis, 4 separate primers (two forward and two reverse) were synthesized. Two PCR products were amplified from Ac-asp-2/pPICZ A plasmid, labeled with 32P-CTP, and hybridized under stringent conditions (65° C.). Approximately 500,000 plaques were screened. Of the remaining colonies not worked up under the above section, the remaining colonies were pooled and re-screened with Ac-asp-2 cDNA fragment. Preparation of Necator Americanus cDNA Library and Original Screening of the Library with Ac-asp-2 Clone. The 2 positive clones obtained from heterologous library screening were subjected to DNA sequencing. The 2 positive clones were identical, each encoding an ORF with homology to Ac-asp-2 (SEQ ID NO: 19)(designated as Na-asp-2). The Na-asp-2 cDNA consisted of 731 bp with a 3′ poly (A) tail. However, no 5-initiation codon was identified. The Na-asp-2 cDNA encodies a predicted ORF of 206 amino acids, lacking initial Met at the N-terminus. Amplification of Na-asp-2 cDNA and Ligation into pPICZ A Copy DNA was amplified and successfully ligated into pPICZ A. Except for the histag at the C-terminus both of the two clones described above were identical. However, compared with the original sequence, there was a single mutation at position 119 from T to A. This resulted in a conservative substitution of a Leu to Met at amino acid 36 (the position is based on the original full length sequence). 5′-RACE to Obtain the 5′-end of Na-asp-2 cDNA Two clones were obtained by 5′RACE. Each contained the full length 5′ end. These were designated 4a1 and 4a2. Sequence alignment of the full length clone revealed that 4a1 exhibited three bp changes. However, 4a2 showed no bp changes from the original cDNA clone. The predicted ORF of 4a2 revealed that Na-ASP-2 (SEQ ID NO: 69) exhibits approximately 60-70% amino acid identity with Ac-ASP-2 (SEQ ID NO: 12). Re-screening of Na L3 cDNA Library with Ac-asp-2 cDNA Fragment 16 positive clones were identified, each exhibiting different intensities. By secondary screening 6 single colonies were obtained, PCR amplified and sequenced. Four of the 6 clones were identical. One of the other clones was identical except at position 119 which exhibited a T to A mutation. A sixth clone was an entirely new gene product that represented a double-domain pathogenesis related protein superfamily gene product (tentatively designated as Na-asp-7). Repeat Re-screening of Na L3 Library 11 additional plaques were obtained, and their cDNA inserts were sequenced. At NGC. From this re-screening a total of 11 cDNAs were obtained. Each of these contained clearly defined Na-asp-2 sequences, which were identical except for variation at positions 55, 61, 66, 119, 193, 451, 496, and 650. However only two of these mutations resulted in amino acid alterations. These included, mutation at position 119, which resulted in either the appearance of a methionine or leucine and a mutation at position 66, which resulted in either the appearance of an alanine or glycine. Transformation of Na-asp-2 cDNA into Pichia Pastoris pPICZ A DNA containing the Na-asp-2 coding sequence was prepared as described in RR-3001 and transformed into Pichia pastoris by electroporation. Four X33 strain colonies containing the presumptive Na-asp-2 sequence were selected, and the presence of an insert was confirmed by PCR in three of the four colonies. To generate Research Seed Stock #1, colony number 2 was selected and grown in YPD, prior to storage at −70 C in YPD containing 25% glycerol. Subsequently, Research Seed Stock #1 was expanded twice, first in BMG, and subsequently in YPD. The DNA sequence and copy number was confirmed. Transformation of Na-asp-2 DNA into Pichia Pastoris pPICZ A DNA containing the Na-asp-2 coding sequence (without histag and without N-terminal signal peptide) was prepared. Plasmid DNA containing the Na-asp-2 coding sequence was transformed into Pichia pastoris as described in the Invitrogen Pichia expression manual (EasySelect™ Pichia Expression Kit, Version F 000526; 25-0172).Zeocin (all transformants integrate at 5′ AOX1 locus by single crossover). Briefly, the plasmid DNA was linearized with Sac1 and transformed into Pichia pastoris strain X33 and GS115 (Mut+) using electroporation. The transformants were plated on medium containing Zeocin (all transformants integrate at 5′ AOX1 locus by single crossover; Mut phenotype is determined by the strain used). Four colonies containing the presumptive Na-asp-2 DNA were selected. Each of these was from the X33 strain. The presence of Na-asp-2 DNA was confirmed by PCR using the following vector primers: 3′ AOX1 5′-GCAAATGGCATTCTGACATCC-3′ (SEQ ID NO: 74) α-factor 5′-TACTATTGCCAGCATTGCTGC-3′ (SEQ ID NO: 75) The presence of an insert was confirmed by PCR in three of the four colonies. Sequencing Expanded research seed stocks were subjected to PCR using the vector primers described above, and subjected to DNA sequencing. DNA sequencing was conducted at the Nevada Genomics Center. Na-asp-2 cDNA without signal peptides at the 5′ end and with stop codon at the 3′ end was cloned with the correct reading frame. There were no nucleotide mutations observed following Na-Asp-2/pPICZA transformation into Pichia pastoris X-33 and subsequent expansions. Only a single copy of Na-asp-2 DNA was observed in both the research seed stock as well as colonies from the original Zeocin plate. Determination of Copy Number Genomic DNA was extracted both from colonies of the original Zeocin plate and expanded. This was done using the YeaStar Genomic DNA Kit (Zymo Research, Cat. # D2002). Na-asp-2 probe was amplified from Na-asp-2-pPICZαA plasmid and labeled with digoxin as described in PCR DIG Probe Synthesis Kit (Roche, Cat #1636090) and used to probe a Southern blot containing research seed clone DNA. Only a single copy of Na-asp-2 DNA was observed in both the research seed stock as well as colonies from the original Zeocin plate. References for Example 15 Hawdon J M, Narasimhan S, Hotez P J. Ancylostoma secreted protein 2: cloning and characterization of a second member of a family of nematode secreted proteins from Ancylostoma caninum. Molec. Biochem. Parasitol. 1999; 99: 149-65. Zhan B, Hawdon J, Shan Q, Ren H N, Qiang H Q, Xiao S H, Li T H, Feng Z, Hotez P. Construction and analysis of cDNA library of Necator americanus third stage larvae. Chin. J. Parastiol. Parasitic Dis. 2000; 18: 26-9. Xue J, Liu S, Qiang H Q, Ren H N, Li T H, Xue H C, Hotez P J, Xiao S H. Necator americanus: maintenance through one hundred generations in golden hamsters (Mesocricetus auratus). I. Host sex-Associated Differences in Hookworm Burden and Fecundity. Exp. Parasitol. 2003; 104: 62-6. Example 16 Cloning and Canine Vaccine Trial of Ac-GST Cloning Cloning of the protein GST from Ancylostoma caninum was carried out by identifying homologous EST fragments of Ac-GST from A. caninum an L3 cDNA library by searching with WU-Blast2 using the Sj28 (S. japanicum) GST sequence. Primers were designed based on sequence information and the 5′ and 3′ ends of Ac-GST were isolated from A. caninum L3 cDNA by using GeneRacer kit (Invitrogen). A full length AcGST was obtained (FIG. 57A, SEQ ID NO: 76). The deduced amino acid sequence is shown in FIG. 57B (SEQ ID NO: 77), and the alighment of the cDNA and the amino acid sequence is shown in FIG. 57C. The coding sequence was clained into pPICZaA in the correct reading frame and the entire sequence was confirmed by re-sequencing from both strands. Vaccine Trial A canine vaccine trial was completed with the following vaccine antigens tested as shown in Table XVI. TABLE XVI Canine vaccine trial description Antigen Expression Vector Amount Immunization Aduvant Route Ac-CYS Pichia pastoris 100 ug Four AS03 i.m. Ac-MTP-2 Pichia pastoris 100 ug Four AS03 i.m. Ac-GST Pichia pastoris 100 ug Four AS03 i.m. Adjuvant alone — — Four AS03 i.m. Irradiated L3 — 1000 L3 Four — sc Experimental Design and Methods Purpose of the Study: The purpose of the study is to test the protective effects in laboratory dogs of vaccines containing various recombinant protein antigens derived from the canine hookworm Ancylostoma caninum. These include recombinant glutathione S transferase (GST), cystatin, and MTP-2. All antigens are given in combination with the GSK adjuvant AS03 and are compared with an AS03 negative control. In addition, a fifth arm of the study employs radiation-attenuated (irradiated) infective larvae, a positive control. Brief Outline of Study Sections: Purpose bred beagles were randomized into five groups. Four groups were given one of three candidate vaccines: Ac-Cystatin, Ac-MTP-2 and Ac-GST in combination with the adjuvant ASO3. One group will serve as the negative control receiving the adjuvant only. Another group will be a positive control immunized with irradiated infective larvae. Each animal's specific antibody response was evaluated by direct ELISA using serum taken prior to the infective challenge. Cellular immune responses were assessed by peripheral (blood cells) lymphoproliferative responses to specific recombinant antigens and/or crude extract of infective larvae (L3) or adult worms. Local cellular immune responses were performed post mortem with lymphocytes extracted from mesenteric lymph nodes and, if considered, spleen. After immunization, animals were challenged with a known number dose of infective third stage larvae of A. caninum. Quantitative ova counts, used to evaluate worm burden, were determined from fecal samples collected three times per week. These data were augmented by periodic blood values to monitor any anemia induced by the parasites and finally necropsy examination to confirm parasite load by counting, weighing, sexing and measuring adult worms. Tissues from different organs were examined macro and microscopically to assess any consequence of the vaccine, parasite or immune related lesions. Test and Control Identification: Test and control articles were prepared for injection by mixing with the adjuvant. The experimental vaccines were comprised of the antigens Ac-Cystatin and Ac-MTP-2 and Ac-GST (expressed all in Pichia pastoris) in combination with the adjuvant ASO3. Animals: The test and control animals were purpose bred, parasite naïve male beagles 56±7 days of age. The trial was terminated twenty seven (27) days after parasite infection. Administration of Test and Control Articles: The vaccines and adjuvant were administered intramuscularly (IM) three (3) times beginning when the dogs are 62+/−4 days old. The vaccines are boosted at 21+/−3-day intervals. Four doses of the vaccines were given 21 days apart (days 0, 21, 42, and 52). The dogs were challenged percutaneously with 500 A. caninum L3, 14 days after the final vaccination. Serum Samples for Quantitative ELISA Antibody Titers: Animals treated with vaccines containing foreign proteins develop an immune response resulting in an increased level of high affinity serum antibodies that are directed against the antigen. Quantitative ELISA using the antigenic proteins demonstrated the relative avidity of the immune response and provide a data set that can be applied to the identification and analysis of hookworm resistant animals. White blood cells were collected for immunological measurements nine (9) days after the last boost and at the time of euthanasia to address the cellular immune response status and cytokine production upon in vitro restimulation of lymphocytes. Cellular Immunology Studies: Blood samples were taken from each animal at scheduled intervals by the veterinary technologist in heparanized tubes. Lymphoproliferation assays were performed in vivo on blood, and post mortem on blood and mesenteric lymph nodes. Challenge Infection: Ancylostoma caninum larvae were cultured from the eggs collected in the feces of infected dogs. All hookworms in the infective challenge were approximately equal age (17±7 days). The species identity of the infective larva dose were validated using PCR DNA amplification and specific oligonucleotide primers. Overnight-collected feces of A. caninum-infected dogs were cultured, extracted and counted. All dogs were infected by the footpad method with the same dose (500+/−5%, of 3rd stage larvae of A. caninum. Larval challenge occurs on one of three consecutive days (at age 120+/−9 days) in 5 series. To minimize the difference in the infective L3 doses, each series included one dog from each (A-E group). Larval Irradiation: The irradiated larvae vaccinations were performed in 2 subcutaneous doses of 1,000 L3 at each vaccination with intervals of 3 weeks between the doses. The challenge was performed 4 weeks after the second dose of vaccination. The irradiated larvae were obtained by irradiation with 40 krad from Cesium (137) as described in SOP 38.1 and a single batch of irradiated larvae was used for both doses of vaccinations. Observations, Hematology, Serum Chemistries: The dogs were observed daily and were weighed at least every 18 days. Dogs that develop signs of moderate to severe anemia, diarrhea or develop a loss of body weight greater than 15% were observed more frequently. Anemia is considered mild (HCT 27-33%), moderate (HCT 21-26%) or severe (HCT<20). Prior to larval infection and at least one time every 21 days, blood samples are collected from all dogs. Blood withdrawal should be approximately equal in amount from all dogs. At this time, the mucous membranes are examined for pallor. A pre-vaccination blood sample was utilized for CBC (hematology), serum chemistries, and a sample of serum will be frozen. The CBC includes: HCT (hematocrit), Hb (hemoglobin), MCHC (mean corpuscular hemoglobin content) and count of WBC (white blood cells), neutrophils, eosinophils, platelets, and monocytes/lymphocytes. Serum chemistries include: ALB (albumin), ALKP (alkaline phosphatase), ALT (alanine aminotranspherase), TBIL (total bilirubin), TP (total protein), Phos (phosphorous), Ca (calcium), BUN (urea nitrogen), CREA (creatinine), AMYL (amylase), Chol (cholesterol), & Glu (glucose). The first CBC was performed approximately five (5)± two (2) after parasite infection. Quantitative Egg Counts (QEC): Twelve days (12±3) following parasite dosing, fecal examination for ova began and continued three times a week (generally M, W, F) until termination. The ova count method was performed according to the current version of SOP 7, which is a modification of the McMaster technique (Veterinary Clinical Pathology, 6th ed., 1994, page 9-10). The test was performed in the same way each time in order to quantitate the ova count. The ova were counted in a McMaster chamber under a binocular microscope and recorded. At this time fecal specimens were examined for the presence of gross blood and notation made on the animal observation form if blood is observed. Adult Worm Count. Adult worms retained in the small and large intestines were collected. The small and large bowel will be collected and the small intestine will be suspended (the large bowel will not be suspended) in a container and incubated for at least two hours at 35° C. saline to collect the adult parasites. The adult worms were separated from the intestinal contents, counted, and preserved in formalin for subsequent count and analysis of sex, length and weight. Results and Analysis The different groups in this vaccine trial are labeled as follows: A or 1: Cystatin+AS03; B or 2: MTP-2+AS03; C or 3: GST+AS03; D or 4: AS03; E or 5: Irradiated 3. As shown in Table XVII high antibody titers were achieved with each group following four immunizations. TABLE XVII Antibody titers in HV-12 Antigen/Dog IgG1 IgG2 Cystatin A1 40,500 121,500 A2 121,500 364,500 A3 364,500 1,093,500 A4 121,500 364,500 A5 121,500 364,500 GEOMEAN 121,500 364,500 Ac-MTP2 B1 121,500 364,500 B2 40,500 121,500 B3 121,500 121,500 B4 40,500 121,500 B5 40,500 40,500 GEOMEAN 62,850 121,500 GST C1 13,500 40,500 C2 13,500 121,500 C3 13,500 40,500 C4 13,500 40,500 C5 13,500 40,500 GEOMEAN 13,500 50,452 L3 Extract E1 13,500 4,500 E2 13,500 1,500 E3 13,500 4,500 E4 13,500 500 E5 13,500 4,500 GEOMEAN 13,500 2,328 The adult hookworms recovered from each of the vaccinated dogs is shown in Table XVIII. TABLE XVIII Adult Hookworm Worm Counts in HV-12 Intestine Colon Male Female Unk. Sex Male Female Unk. Sex Total A1 81 85 1 0 167 A2 38 29 0 0 67 A3 48 67 1 3 5 124 A4 36 41 0 2 79 A5 44 56 0 0 100 Average 49 56 107 B1 64 71 11 10 156 B2 49 51 2 3 105 B3 41 41 1 2 85 B4 64 65 9 15 153 B5 87 73 1 0 161 Average 61 60 132 C1 50 81 0 0 131 C2 34 26 4 3 67 C3 19 36 0 0 55 C4 33 36 7 4 80 C5 33 41 2 5 81 Average 34 44 83 D1 49 0 1 113 D2 27 29 0 0 56 D3 62 61 0 2 125 D4 75 82 0 2 159 D5 108 119 3 2 232 Average 64 71 137 E1 7 10 4 9 30 E2 43 40 0 1 84 E3 28 118 4 5 155 E4 20 24 0 0 44 E5 12 15 3 5 35 Average 22 41 2 4 70 Although a promising trend was noted in the GST and cystatin vaccinated group (40 and 51 percent reduction relative to AS03 controls, respectively), for this trial the variance was too great for the small sample size and that only the IrL3 is statistically significant and, then only when the Dunnett 2-sided post hoc test (the standard for clinical trials) was used. However as shown in the Appendix, if an outlier is removed from the control group, statistical significance is obtained. An outlier is defined as an observation far from the rest of the data; it may represent valid data or a mistake in experimentation, data collection, or data entry. An outlier can have an extremely large effect on when testing for differences of means. While it is common to remove outliers, it must be done with some rules and with consistency. There is statistical significance for both GST and IrL3, by using the 5% Trimmed Mean. This is the arithmetic mean calculated when the largest 5% and the smallest 5% of the cases have been eliminated. Eliminating extreme cases from the computation of the mean results in a better estimate of central tendency, especially when the data are non-ormal. This is common, well-accepted, and a method preferential to removing outliers because it is done by the statistical program itself. The results from an SPSS output for GST, IrL3, and Control groups are shown below in yellow for the 5% trimmed mean The results for the t-tests were: GST vs. Control (t=1.6874; p=0.0458); IrL3 vs. Control (t=1.8851; p=0.0297). A comparison of the resulting hookworm counts is given in FIG. 59. As shown in FIG. 60, there was also a reduction in the mean and median hookworm quantitative egg counts in dogs receiving L3 irradiated and Ac-GST. This example shows that high antibody titers were produced to each of the recombinant antigens. After larval challenge, both GST and irradiated L3 vaccinated groups exhibited high levels of worm burden reduction (41 and 50%, respectively). However, because of high variation within the control group, the worm burden reduction was statistically significant with either removal of outliers or using trimmed means. In addition there was significant reduction in quantitative egg counts. These studies confirmed the protection afforded by irradiated L3 and indicate that GST is a promising vaccine antigen. Example 17 Hamster Vaccine Trial These studies were undertaken to confirm the protective effects of Ay-ASP-2 observed in Ham V-3 (Goud et al, 2004). The results confirm that ASP-2 is a protective antigen, both in terms of worm burden reduction and in worm fecundity. In addition there was less blood loss among the ASP-2 vaccinated group. The study also found that ASP-1 had greater protective efficacy than observed in Ham V-3. The results also found that the addition of MTP to the vaccine cocktail increases the protective effect. Experimental Design and Methods Purpose of the Study: The purpose of the study is to test the protective effects in laboratory hamsters of vaccines containing various recombinant protein antigens derived from hookworms and other parasites, against hookworm infection. Brief Outline of Study Sections: Purpose bred Syrian hamsters are randomized into eight groups. Seven groups will receive candidate vaccines: ASP-1, ASP-2, MTP, and Irradiated larvae. One group receives only the adjuvant (Quil A) as experimental control. Each animal's specific antibody response is evaluated by direct ELISA using serum taken prior to the infective challenge. After the immunized animals demonstrate a positive immune response to the vaccines, they are challenged with a known number dose of infective third stage larvae of A. ceylanicum. Quantitative ova counts, used to evaluate worm burden, are made from fecal samples collected twice after larval challenge. Also, hemoglobin levels will be tested to detect anemia caused by the blood loss during adult hookworm infection. The final report will evaluate the data and provide conclusions regarding each vaccine's effectiveness both in terms of worm burden and blood loss. Positive Result Indicators: A successful positive result in this study will be a demonstrated increase in specific antibody titers in immunized animals and protection against hookworm burden and hookworm-associated blood loss. The hemoglobin test detects anemia caused by the blood loss during adult hookworm infection. The experimental control data obtained from un-immunized animals will serve as a basis for evaluating the success of the study and also to check any parasitic infection. Test and Control Identification: The antigens are ASP-1, ASP-2, and MTP. The antigen-adjuvant combinations will be ASP-1+Quil A, ASP-2+Quil A, MTP+Quil A, ASP-1+ASP-2+Quil A, ASP-2+MTP+Quil A and ASP-1+MTP+Quil A. One group, which receives irradiated L3 serve as the positive control. The negative control group will receive only Quil A. Details about the antigen and the adjuvants will be included in the study records when they become available. The test articles are diluted to provide a dose of 0.025 mg of antigen in 200 ul of antigen-adjuvant mixture per animal per injection. All injections will be performed intramuscularly (i.m). The prescribed volume dose information is recorded by Dr. Ghosh. Fresh preparation of antigens will be made the day of injection. Selection and Justification of Test System: Hamsters are selected as the test system because they are susceptible to infection by a hookworm species that causes a serious but often non-fatal disease. Hamsters make an excellent model because hookworm-induced anemia caused by A. ceylanicum is better reflected in hamsters. Previous studies have documented there are many parameters associated with hookworm induced anemia that contribute to the quantitative evaluation of the vaccine study success. Animals: The test and control animals will be purpose bred, parasite naïve, 23±2 days old and 50±5 gm body weights on arrival. Following 5-9 days quarantine, the hamsters are started on the vaccination schedule. The hamsters will be identified by a small metallic ear tag plate, each of which contain a number for the identification of the hamster. Hamsters are randomized into five (6) vaccine test groups containing ten (10) hamsters each and two (2) control group of ten (10) hamsters. The hamsters are then assigned permanent hamster-study numbers (e.g. Ham V-IV) as follows: Ham V-IV (A. ceylanicum Vaccine Trial IV), vaccine or control groups A, B, C, D E, F, G and H. Each hamster will have unique Ear Tag number viz., 301. Attempts will be made to treat each hamster in the same manner. Each hamster on a trial will receive the same treatment, housing, dose of larvae and diet. Administration of Test and Control Articles: The vaccines and adjuvant are administered intramuscularly (IM) three (3) times beginning when the hamsters are 28±2 days old. The vaccines are boosted at 21 days (3 weeks) intervals. Serum Samples for Quantitative ELISA Antibody Titers: Animals treated with vaccines containing foreign proteins are expected to develop an immune response resulting in an increased level of high affinity serum antibodies that are directed against the antigen. Since the hookworms feed on blood, antibodies in the host circulatory system are likely to come in contact with the parasite. If these antibodies recognize an antigen that is essential for initiation or maintenance of the parasitic state, immune reactions may exert a protective effect that causes a significant change in the critical infection parameters (i.e. egg counts, blood values, worm number, or worm size). Quantitative ELISA using the antigenic proteins will demonstrate the relative avidity of the immune response and will provide a data set that can be applied to the identification and analysis of hookworm resistant animals. Challenge Infection: Ancylostoma ceylanicum larvae are cultured from the eggs collected in the feces of infected hamsters by qualified technicians in the Dr. Hotez lab. All hookworms in the infective challenge are approximately equal age (10±5 days). The species identity of the infective larva dose is validated, using PCR DNA amplification and specific oligonucleotide primers. All hamsters are infected by orally with the same dose of 100+/−10 3rd stage larvae of A. celyanicumfs. Larval challenge occurs on the same day for all hamsters (at age 82±2 days). Clinical Observations: The hamsters are observed daily and are weighed at least every 7 days post-challenge. Hamsters that develop signs of moderate to severe anemia, or develop a loss of body weight greater than 15% are observed more frequently. Prior to larvae infection and at least one time every 7-10 days, blood samples are collected from all hamsters. Blood withdrawal should be approximately equal in amount from all hamsters and at this time, the stool will be checked for blood. A pre-vaccination blood sample will be examined for Hemoglobin; a sample of serum will be frozen. A hemoglobin test is performed 6-10 days and 12-18 days post-challenge. Samples of serum will be collected from each hamster; pre-immune, after 2 boosts, and after larval challenge. These samples will be labeled with unique identifiers (nature of the specimen, study-hamster number and collection date) and frozen for possible future analysis. Quantitative Egg Counts (QEC): One week following parasite dosing, fecal examination for ova begins and will be repeated once a week until the study is terminated. The ova count method will be performed according to the SOP, which is a modification of the McMaster technique (Veterinary Clinical Pathology, 6th ed., 1994, page 9-10). The test will be performed the same way each time in order to quantitate the ova count. Fecal specimens from the hamsters will be identified by the hamster study number and the unique hamster identification number. The ova are counted in a McMaster chamber under a binocular microscope and recorded. Termination: Hamsters that appear to be suffering (and the pain cannot be relieved) or become moribund are euthanized. All hamsters that are euthanized or die spontaneously are necropsied. The study is terminated 4 to 5 weeks (+/−3 days) after parasite infection. Three groups of hamsters will be euthanized on each day of necropsy with one of the groups being a group of control hamsters. Halothane will be used for euthanasia. Necropsy: A complete necropsy is performed. Lesions are described, the entire small and large intestine is collected, and tissues are fixed in formalin. The ear tags will be retained with the tissues in formalin. Adult Worm Count: The small and large intestines are collected and incubated in a petri dish for a few minutes at 37° C.±7° in saline to facilitate the collection of adult parasites. The adult worms are separated from the intestinal contents, counted, and preserved in formalin for subsequent count and analysis of sex. Statistical Methods: Both parametric and non-parametric tests will be used to analyze the data. Statistical comparisons for each outcome variable will be performed at the two-sided=0.05 level of significance. Variables that will be analyzed are: Number of worms in the intestine and the colon; Egg counts per gram; Antibody titers; Hemoglobin and Body Weight of hamsters. Results and Discussion. The Geometric mean of antibody titers for each group under study are given in FIG. 77A, and the reduction in worm burden is depicted in Table XIX and graphically in FIG. 77B. As can be seen, the results confirm that ASP-2 is a protective antigen, both in terms of worm burden reduction and in worm fecundity. In addition, there was less blood loss among the ASP-2 vaccinated group. The study also found that ASP-1 had greater protective efficacy than observed in Ham V-3. The results also found that the addition of MTP to the vaccine cocktail increases the protective effect. TABLE XIX Hookworm burden reductions following vaccination with recombinant antigens or irradiated A. ceylanicum L3 followed by A. ceylanicum L3 challenge. Percentage Adult Hookworms Reduction Experimental Mean Relative P (one Groups (Median) ± 1 SD to Quil A sided) Ay-ASP-1 30.9 (36.0) ± 13.8 36.8 0.003* Ay-ASP-2 33.2 (39.5) ± 15.2 32.1 0.005* Ay-MTP 35.3 (40.0) ± 19.6 27.8 0.026 Ay-ASP-2 + 43.7 (43.5) ± 20.4 10.6 0.29 Ay-ASP-1 Ay-ASP-2 + 31.4 (31.5) ± 13.4 35.8 0.002* Ay-MTP Ay-ASP-1 + 27.0 (29.0) ± 20.0 44.8 0.011 Ay-MTP Quil A 48.9 (53.0) ± 12.9 — — (Adjuvant control) Irradiated L3 6.8 (4.5) ± 5.5 86.1 0.001* * P ≦ 0.007 is considered significant after Bonferroni correction Table XX shows data regarding hookworm egg reduction. TABLE XX Hookworm eggs (EPG) reductions following vaccination with recombinant antigens or irradiated A. ceylanicum L# followed by A. ceylanicum L3 challenge. Percent reduction Experimental Groups EPG Mean ± SD relative to Quil A Ay-ASP-1 912.5 ± 17.7 59.0 Ay-ASP-2 1175.0 ± 176.7 47.2 Ay-MTP 1275.0 ± 777.8 42.7 Ay-ASP-2 + Ay-ASP-1 1312.5 ± 1007.6 41.0 Ay-ASP-2 + Ay-MTP 1012.5 ± 512.7 54.9 Ay-ASP-1 + Ay-MTP 1025.0 ± 707.11 53.9 Quil A 225.0 ± 1343.5 — (Adjuvant control) Irradiated L3 25.0 ± 0.000 98.9 Additional date concerning blood loss is given in Table XXI. TABLE XXI Hemoglobin reduction at necropsy relative to hemoglobin at the time of experimental infection of hamsters with A ceylanicum L3, and its comparison with control group. Percentage Hb Increase Experimental Hb % change Mean Relative to P (one Groups (Median) ± 1 SD control (QuilA) sided) Ay-ASP-1 −13.3 (−20.0) ± 20.0 32.7 0.022 Ay-ASP-2 −9.2 (−13.3) ± 16.0 55.2 0.003* Ay-MTP −3.5 (−11.9) ± 30.0 59.9 0.018 Ay-ASP-2 + −17.9 (−23.2) ± 24.3 21.9 0.11 Ay-ASP-1 Ay-ASP-2 + −15.2 (−17.2) ± 10.3 42.1 0.008 Ay-MTP Ay-ASP-1 + 0.8 (5.4) ± 18.0 118.2 0.002* Ay-MTP Quil A −29.7 (−32.5) ± 14.8 — — (Adjuvant control) Irradiated 13.7 (21.4) ± 17.6 172.1 <0.0001* L3 Minus sign means percentage decrease *P ≦ 0.007 is considered significant after Bonferroni correction FIG. 78B display this data graphically. Table XXII gives spleen weights of hamsters per experimental group. TABLE XXII Spleen weights of hamsters per group. Experimental groups Spleen weights (gr) Mean (Median) ± 1 SD Ay-ASP-1 0.48 (0.48) ± 0.10 Ay-ASP-2 0.44 (0.47) ± 0.13 Ay-MTP 0.42 (0.45) ± 0.13 Ay-ASP-2 + Ay-ASP-1 0.45 (0.48) ± 0.13 Ay-ASP-2 + Ay-MTP 0.42 (0.44) ± 0.08 Ay-ASP-1 + Ay-MTP 0.44 (0.42) ± 0.12 Quil A 0.47 (0.45) ± 0.06 (Adjuvant control) Irradiated L3 0.23 (0.23)±0.09 Table XXIII shows data concerning body weight reduction of hamsters at necropsy. TABLE XXIII Body weight reduction of hamsters at necropsy relative to their weight at the time of experimental infection with A. ceylanicum L3, and its comparison with control group. Body Weight % Reduction Group Mean (Median) ± 1 SD P Ay-ASP-1 3.4 (4.4) ± 5.9 0.02 Ay-ASP-2 4.2 (4.9) ± 4.8 0.03 Ay-MTP 4.0 (5.4) ± 6.0 0.04 Ay-ASP-2 + Ay-ASP-1 4.7 (5.4) ± 3.9 0.04 Ay-ASP-2 + Ay-MTP 4.0 (5.2) ± 4.1 0.04 Ay-ASP-1 + Ay-MTP 5.5 (7.2) ± 4.4 0.20 Quil A 7.9 (7.8) ± 3.0 — (Adjuvant control) Irradiated L3 4.2 (5.2) ± 3.3 0.02 In addition, FIGS. 80A and B illustrate IgG titers vs median worm burden (A) and EPG (B). This example demonstrates that a significant reduction in worm burden was observed for animals vaccinated with ASP-1, ASP-2, ASP-2+MTP, and irradiated L3. In these animals, an overall reduction in egg count from 41% to 98.9% was observed. Significantly higher hemoglobin was observed in animals vaccinated with ASP-2, ASP-1+MTP and irradiated L3 (P≦0.007, and for ASP-2+MTP, P=0.008). Further, a statistically significant negative correlation was observed between spleen weight and hemoglobin (P<0.001). Reference Cited in Example 17 Goud G N et al. 2004. Cloning, yeast expression, isolation, and vaccine testing of recombinant Ancylostoma-secreted protein (ASP)-l and ASP-2 from Ancylostoma ceylanicum. Journal of Infectious Diseases 189: 919-29 While the invention has been described in terms of its preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the appended claims. Accordingly, the present invention should not be limited to the embodiments as described above, but should further include all modifications and equivalents thereof within the spirit and scope of the description provided herein. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The invention generally relates to a vaccine for hookworm. In particular, the invention provides vaccines based on parasite-derived antigens. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides preparations for eliciting an immune response against hookworm. The preparations contain various hookworm antigens which have been identified as useful for eliciting an immune response. These preparations may be used as vaccines against hookworm in mammals, for example, in humans. As a result of the administration of the preparations, the vaccinated mammal may develop an immune response against hookworm which causes immunity to infection by the parasite, or may display a lower worm burden, decreased blood loss, or a decrease in size of parasitizing hookworms. To that end, the invention provides a composition comprising a recombinant or synthetic antigen or a fragment thereof derived from hookworm, and a pharmacologically acceptable carrier. The recombinant or synthetic antigen may display at least about 80% identity to an antigen such as ASP-1, ACE, CTL, APR-1, APR-2, TMP, MEP-1, MEP-2, ASP-1, ASP-2, ASP-3, ASP-4, ASP-5, ASP-6, TTR-1, TTR-2, 103 (also referred to as SAA-1), 16, VWF, CTL, API, MTP-1, MTP-2, MTP-3, FAR-1, KPI-1, APR-1, APR-2, AP, ASP-1, ASP-2, API, CP-1, CP-2, CP-3, CP-4, CYS, and GST. In preferred embodiments, the antigen is ASP-1, ASP-2, MTP-1, 103 (SAA), 16, GST, TMP, MEP-1, APR or CP-2. The antigens may be derived from a hookworm from species such as Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum , and Ancylostoma duodenale. The invention also provides a method of eliciting an immune response to hookworm in a mammal. The method includes the step of administering to the mammal an effective amount of a composition comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm, and a pharmacologically acceptable carrier. The recombinant or synthetic antigen may display at least about 80% identity to an antigen such as ASP-1, ACE, CTL, APR-1, APR-2, TMP, MEP-1, MEP-2, ASP-1, ASP-2, ASP-3, ASP-4, ASP-5, ASP-6, TTR-1, TTR-2, 103 (also referred to as SAA-1), 16, VWF, CTL, API, MTP-1, MTP-2, MTP-3, FAR-1, KPI-1, APR-1, APR-2, AP, ASP-1, ASP-2, API, CP-1, CP-2, CP-3, CP-4, CYS, and GST. In preferred embodiments, the antigen is ASP-1, ASP-2, MTP-1,103 (SAA), 16, GST, TMP, MEP-1, APR, or CP-2. The antigens may be derived from a hookworm from species such as Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum , and Ancylostoma duodenale. The invention further provides a method of vaccinating a mammal against hookworm. The method includes the step of administering to the mammal an effective amount of a composition comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm and a pharmacologically acceptable carrier. The recombinant or synthetic antigen may display at least about 80% identity with an antigen such as ASP-1, ACE, CTL, APR-1, APR-2, TMP, MEP-1, MEP-2, MTP-1, ASP-1, ASP-2, ASP-3, ASP-4, ASP-5, ASP-6, TTR-1, TTR-2, 103 (also referred to as SAA-1), 16, VWF, CTL, API, MTP-1, MTP-2, MTP-3, FAR-1, KPI-1, APR-1, APR-2, AP, ASP-1, ASP-2, MTP-1, API, CP-1, CP-2, CP-3, CP-4, CYS, and GST. In preferred embodiments, the antigen is ASP-1, ASP-2, MTP-1, 103 (SAA), 16, GST, TMP, MEP-1, APR, or CP-2. The antigens may be derived from a hookworm from species such as Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum , and Ancylostoma duodenale. The invention further provides a composition comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm. The recombinant or synthetic antigen display at least about 80% identity with an antigen such as ASP-1, ACE, CTL, APR-1, APR-2, TMP, MEP-1, MEP-2, ASP-1, ASP-2, ASP-3, ASP-4, ASP-5, ASP-6, TTR-i, TTR-2, 103 (also referred to as SAA-1), 16, VWF, CTL, API, MTP-1, MTP-2, MTP-3, FAR-1, KPI-1, APR-1, APR-2, AP, ASP-1, ASP-2, API, CP-1, CP-2, CP-3, CP-4, CYS, and GST. The composition further comprises a pharmacologically acceptable carrier. In preferred embodiments, the antigen is ASP-1, ASP-2, MTP-1, 103 (SAA), 16, GST, TMP, MEP-1, APR, or CP-2. The antigens may be derived from a hookworm from species such as Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum , and Ancylostoma duodenale. The invention further provides a vaccine comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm. The recombinant or synthetic antigen displays at least about 80% identity with an antigen such as ASP-1, ACE, CTL, APR-1, APR-2, TMP, MEP-1, MEP-2, ASP-1, ASP-2, ASP-3, ASP-4, ASP-5, ASP-6, TTR-1, TTR-2, 103 (also referred to as SAA-1), 16, VWF, CTL, API, MTP-1, MTP-2, MTP-3, FAR-1, KPI-1, APR-1, APR-2, AP, ASP-1, ASP-2, API, CP-1, CP-2, CP-3, CP-4, CYS, and GST. The vaccine further comprises a pharmacologically acceptable carrier. In preferred embodiments, the antigen is ASP-1, ASP-2, MTP-1, 103 (SAA), 16, GST, TMP, MEP-1, APR, or CP-2. The antigens may be derived from a hookworm from species such as Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum , and Ancylostoma duodenale. The present invention further provides a composition for eliciting an immune response comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm. The recombinant or synthetic antigen displays at least about 80% identity with an antigen selected from the group consisting of ASP-1, ACE, CTL, APR-1, APR-2, TMP, MEP-1, MEP-2, ASP-1, ASP-2, ASP-3, ASP-4, ASP-5, ASP-6, TTR-1, TTR-2, 103 (also referred to as SAA-1), 16, VWF, CTL, API, MTP-1, MTP-2, MTP-3, FAR-1, KPI-1, APR-1, APR-2, AP, ASP-1, ASP-2, API, CP-1, CP-2, CP-3, CP-4, CYS, and GST. The composition further comprises a pharmacologically acceptable carrier. In preferred embodiments, the antigen is ASP-1, ASP-2, MTP-1, 103 (SAA), 16, GST, TMP, MEP-1, APR, or CP-2. The antigens may be derived from a hookworm from species such as Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum , and Ancylostoma duodenale. The invention further provides a method for enabling vaccination of a patient against parasite derived infectious diseases. The method includes the steps of treating hookworm infection to a degree sufficient to increase lymphocyte proliferation, and vaccinating the patient against an infectious disease such as HIV, tuberculosis, malaria, measles, tetanus, diphtheria, pertussis, or polio. The present invention also provides a method for enabling hookworm vaccination. The method includes the steps of chemically treating a hookworm infected patient to ameliorate hookworm infection, and vaccinating the patient with a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm after amelioration of hookworm infection. In the method, the hookworm infection may be completely eradicated by treatment, or may be lessened to such an extent that hookworm vaccination is effective. The recombinant or synthetic antigen may display at least about 80% identity with an antigen such as ASP-1, ACE, CTL, APR-1, APR-2, TMP, MEP-1, MEP-2, ASP-1, ASP-2, ASP-3, ASP-4, ASP-5, ASP-6, TTR-1, TTR-2, 103 (also referred to as SAA-1), 16, VWF, CTL, API, MTP-1, MTP-2, MTP-3, FAR-1, KPI-1, APR-1, APR-2, AP, ASP-1, ASP-2, API, CP-1, CP-2, CP-3, CP-4, CYS, and GSTThe antigens may be derived from a hookworm from species such as Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum , and Ancylostoma duodenale. The present invention also provides a method for reducing blood loss in a patient infected with hookworm. The method includes the step of administering to the patient a composition comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm, and a pharmacologically acceptable carrier. The present invention also provides a method for reducing hookworm size in a patient infected with hookworm. The method includes the step of administering to the patient a composition comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm, and a pharmacologically acceptable carrier. The invention further provides a method of reducing hookworm burden in a patient infected with hookworm. The method comprises the step of administering to the patient a composition comprising a recombinant or synthetic antigen (or a fragment of the antigen) derived from hookworm, and a pharmacologically acceptable carrier. The present invention also provides the following nucleic acid and amino acid sequences: SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 47, SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 51, SEQ ID NO: 52, SEQ ID NO: 55, SEQ ID NO: 56, SEQ ID NO: 57, SEQ ID NO: 58, SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 62, SEQ ID NO: 63 and SEQ ID NO: 64. | 20040416 | 20071204 | 20050224 | 97158.0 | 0 | ZEMAN, ROBERT A | HOOKWORM VACCINE | SMALL | 1 | CONT-ACCEPTED | 2,004 |
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10,825,718 | ACCEPTED | Cleaning system, device and method | The cleaning device may clean probe elements. The probe elements may be the probe elements of a probe card testing apparatus for testing semiconductor wafers or semiconductor dies on a semiconductor wafer or the probe elements of a handling/testing apparatus for testing the leads of a packaged integrated circuit. During the cleaning of the probe elements, the probe card or the handler/tester is cleaned during the normal operation of the testing machine without removing the probe card from the prober. The cleaning device has a working surface with a particular characteristic (a matte finish or a conductive material) so that a prober is capable of automatically determining the location of the working surface of the cleaning device and therefore operate in an automatic cleaning mode. | 1. A cleaning device, comprising: a cleaning pad capable of being adhered to a substrate that cleans a probe element of a prober wherein the probe element is capable of being inserted into the cleaning pad; and wherein the cleaning pad further comprises a working surface into which the probe element is inserted, the working surface having a characteristic that permits the prober to determine the location of the working surface of the cleaning pad. 2. The cleaning device of claim 1, wherein the characteristic of the working surface of the cleaning pad further comprises a matte surface finish that is formed by a release liner removed from the working surface prior to use so that a prober that uses optical energy is able to detect the location of the working surface of the cleaning pad. 3. The cleaning device of claim 1, wherein the characteristic of the working surface of the cleaning pad further comprises a conductive surface so that a prober that uses conductance is able to detect the location of the working surface of the cleaning pad. 4. The cleaning device of claim 3, wherein the cleaning pad further comprises an additive so that the cleaning pad is conductive. 5. The cleaning device of claim 4, wherein the additive further comprises at least one of conductive carbon-graphite particles or fibers, metal plated abrasive particulates or fibers, and metallic particulates or fibers. 6. The cleaning device of claim 3, wherein the cleaning pad further comprises a conductive polymer. 7. The cleaning device of claim 6, wherein the conductive polymer further comprises one of polyanilenes, polypyrroles and polythiophenes. 8. A method for fabricating a cleaning device whose working surface is capable of being detected by a prober device, the method comprising: forming a cleaning device having a working surface; and removing a layer from the working surface wherein the removal of the layer imparts a matte finish to the working surface of the cleaning device. 9. The method of claim 8, wherein forming the cleaning device further comprises forming a first release liner layer, forming a cleaning pad layer having a working surface on the first release liner layer, forming an adhesive layer on the cleaning pad layer, and forming a second release liner layer on the adhesive layer wherein the first release liner layer is removed to create the matte finish of the working surface. 10. A method for the automatic detection of a cleaning device, comprising: detecting a working surface of the cleaning device; and performing a cleaning operation based on the detected working surface of the cleaning device. 11. The method of claim 10, wherein the detecting further comprises directing optical energy towards the working surface of the cleaning device and determining the location of the working surface of the cleaning device based on the optical energy reflected off of the working surface of the cleaning device. 12. The method of claim 10, wherein the detecting further comprises measuring the conductance of the working surface of the cleaning device in order to determine the position of the working surface of the cleaning device. 13. A method for testing semiconductor devices in an automatic cleaning mode, the method comprising: performing testing of semiconductor devices; during the testing operation, automatically determining that a cleaning is to be performed; automatically determining the location of a working surface of a cleaning device based on a characteristic of the working surface; performing the cleaning using the cleaning device; and continuing the testing of semiconductor devices. 14. The method of claim 13, wherein determining that cleaning is to be performed further comprises measuring the parameters of each semiconductor device being tested and initiating a cleaning step when the measured parameters vary from a normal value. 15. The method of claim 13, wherein determining that cleaning is to be performed further comprises performing a cleaning step after a predetermined number of testing operations. 16. The method of claim 13, wherein determining the working surface of the cleaning device further comprises directing optical energy towards the working surface of the cleaning device and determining the location of the working surface of the cleaning device based on the optical energy reflected off of the working surface of the cleaning device. 17. The method of claim 13, wherein determining the working surface of the cleaning device further comprises measuring the conductance of the working surface of the cleaning device in order to determine the position of the working surface of the cleaning device. 18. The method of claim 13, wherein performing the cleaning further comprises moving a probe element in a horizontal motion. 19. The method of claim 13, wherein performing the cleaning further comprises moving a probe element in an orbital motion. 20. A method for cleaning a probe element of a prober for semiconductor devices, the method comprising: providing a cleaning device having pad; inserting the probe element into the pad; and wherein a tip of the probe element is reshaped during the cleaning. 21. A method for refurbishing a probe element of a prober for semiconductor devices, the method comprising: providing a cleaning device having pad; inserting the probe element into the pad; and wherein a tip of the probe element is refurbished during the cleaning. 22. A method for testing packaged semiconductor devices, the method comprising: performing testing of the packaged semiconductor devices; during the testing operation, automatically determining that a cleaning is to be performed; automatically determining the location of a working surface of a cleaning device based on a characteristic of the working surface; performing the cleaning using the cleaning device; and continuing testing of packaged semiconductor devices. 23. The method of claim 22, wherein determining that cleaning is to be performed further comprises measuring the parameters of each semiconductor device being tested and initiating a cleaning step when the measured parameters vary from a normal value. 24. The method of claim 22, wherein determining that cleaning is to be performed further comprises performing a cleaning step after a predetermined number of testing operations. 25. The method of claim 22, wherein determining the working surface of the cleaning device further comprises directing optical energy towards the working surface of the cleaning device and determining the location of the working surface of the cleaning device based on the optical energy reflected off of the working surface of the cleaning device. 26. The method of claim 22, wherein determining the working surface of the cleaning device further comprises measuring the conductance of the working surface of the cleaning device in order to determine the position of the working surface of the cleaning device. 27. The method of claim 22, wherein performing the cleaning further comprises moving a probe element in a horizontal motion. 28. The method of claim 22, wherein performing the cleaning further comprises moving a probe element in an orbital motion. 29. The cleaning device of claim 1, wherein the cleaning pad further comprises an abrasive incorporated into the cleaning pad. 30. The cleaning device of claim 29, wherein the abrasive further comprises one of aluminum oxide, silicon carbide and diamond. | RELATED CASES/PRIORITY CLAIM This application is a continuation in part and claims priority under 35 USC 120 to U.S. patent application Ser. No. 09/624,750, filed on Jul. 24, 2000 and entitled “Cleaning System, Device and Method” which in turn claims priority under 35 USC 119(e) to U.S. Provisional Patent Application No. 60/146,526 filed Jul. 30, 1999. Both applications are incorporated herein by reference. BACKGROUND OF THE INVENTION This invention relates generally to a medium for cleaning a manual test interface while it is still in the prober. This manual interface is generally referred to as a probe card, which is used in the prober to make an electrical connection between the die on a silicon wafer and the tester so that the functionality of the die may be evaluated. Currently, the method for cleaning the probe card is to remove it from the prober and manually clean the debris from the probe tips. The probe tips need to be cleaned to remove debris from them since the debris reduces the quality of the electrical circuit completed by the contact of the probe tips to any surfaces on a die. The completed electrical circuit is used to evaluate the electrical characteristics of the die by the test apparatus. The degradation of the quality of the electrical circuit caused by the probe tip debris may be interpreted by the test apparatus as a failure of the die under test even though the die is functioning correctly. This false failure of the die results in the rejection or the rework of good die thereby increasing the cost of the final products sold. In the industry, it has been seen that a 1% change in yield from an individual prober can equate to more than $1,000,000 per annum. Therefore, with thousands of probers operating worldwide, the impact to the industry from maintaining clean probes during testing can be very substantial. Individual semiconductor (integrated circuit) devices are typically produced by creating multiple devices on a silicon wafer using well known semiconductor processing techniques including photolithography, deposition, and sputtering. Generally, these processes are intended to create multiple, fully functional integrated circuit devices prior to separating (singulating) the individual devices (dies) from the semiconductor wafer. However, in practice, physical defects in the wafer material and defects in the manufacturing processes invariably cause some of the individual devices to be non-functional, some of which may be repairable. It is desirable to identify the defective devices prior to separating or cutting the dies on the wafer. In particular, some product is actually repairable when the flaws are caught at the wafer lever. Other product may not be repairable but may be used in a downgraded application from the original product. This determination of the product's capabilities (a product definition provided by electrical probe testing) at the wafer level saves the manufacturer considerable cost later in the manufacturing process. In addition, product cost may be reduced if defective devices are identified. To enable the manufacturer to achieve this testing capability a probe card, prober and tester are employed to make temporary electrical connections to the bonding pads, solder or gold bumps or any surface on the chip where connection can be made by making manual contact to that surface. The surface may be on the individual circuit device or on multiple circuit devices when the devices are still part of a wafer. Once the connections between the tester and the circuit device are made, power and electrical signals are transferred from the tester to the device for testing, to determine its functionality and whether the device is accepted or rejected for further processing. Typically, the temporary connections to the device bonding elements are made by contacting multiple electrically conductive probes (often needle like structures) against the electrically conductive bonding elements of the device. By exerting controlled pressure (downwards force on the bonding pads) of the probe tips against the bonding pads, solder balls and/or gold bumps, a satisfactory electrical connection is achieved allowing the power, ground and test signals to be transmitted. The tester and prober need a manual interface to the bonding elements on the die to achieve contact. A probe card having a plurality of probes is used to make the connection with the bonding pads of the semiconductor die. The probes may be cantilever beams or needles or vertical beams. Typically, each probe is an inherently resilient spring device acting as a cantilever beam, or as an axially loaded column. A variation is to mount multiple probes in a spring-loaded support. In a conventional prober, the probe card, and its multiple probes, are held in precise mechanical alignment with the bonding elements of the device under test (or multiple devices, or wafer as the case may be) and the device is vertically translated into contact with the tips of the probes. In the typical prober, the tips of the probes may perform a scrubbing action in which the tip of the probes moves horizontally as it contacts the bonding pad in order to scrub away oxide, or any other material on the pad, that may inhibit the electrical contact between the probes and the bonding pads. Although the scrubbing action improves the electrical contact between the probe tip and the bonding pad, it unfortunately also generates some debris (the scraped up oxide or other debris) that may also prevent the probe tip from making a good electrical contact with the bonding pad. Alternatively, the probe tip may press vertically into the bonding pad, solder or gold bump with sufficient force to penetrate any surface material and establish good electrical contact. The probe tip may become contaminated with contaminates such as aluminum, copper, lead, tin, gold, bi-products, organic films or oxides resulting from the wafer and semiconductor device manufacturing and testing processes. Typically, the debris generated by probing needs to be periodically removed from the probe elements to prevent a build-up which causes increased contact resistance, continuity failures and false test indications, which in turn results in artificially lower yields and subsequent increased product costs. Typically, the entire probe card with the plurality of probes must be removed from the prober and cleaned or abrasively cleaned in the prober. In a typical prober, the probe card can be cleaned several times an hour, several time during a single wafer test, several times during a wafer lot, several times before lot start, and several times after lot start. Also, some operators may clean the probe several times during the initial setup of the test equipment. The process of cleaning in the prober using an abrasive pad burnishes the tips but it does not remove the debris. The burnishing actually causes wear to the probe card by shortening the probe tips. In addition, since it does not remove the debris, and since the debris exhibits a slight electrical charge, it attracts more debris so the probe card will require cleaning more often than the original clean card. Currently the debris from burnishing can be removed manually by means of alcohol and a cotton tip swab, an air gun or an inert gas purge. The probers also utilize a brush unit comprised of natural or synthetic fibers to remove debris from the tips of a probe card. However, the brush operation tends to provide inconsistent cleaning and debris removal. The brush operation has the potential to damage the planarity and alignment of the probes and may push contaminants into the array of the probes or up into the probe guide-plates. Furthermore, some of the particulates during this operation may not be captured within the body of the brush and can become air-borne. This is of particular concern when these particulates are environmentally hazardous. Further details of this known brush unit are shown and described in U.S. Pat. No. 5,968,282. Each method cleans the probes but requires stopping the prober or manual intervention to perform the function. Other contaminates, such as lead and tin, may be removed by abrasive cleaning/burnishing or cleaning the probes with a solution that may typically be an acid, for example. When probe cards which have collected lead and tin are burnished, particulates of lead are released into the air that cause environmental hazards. In addition, the acid solution requires a separate, rather expensive machine that sprays the solution onto the tips in a closed chamber. These typical cleaning processes are expensive since the tester will have down time and a replacement card must be purchased to run while the other probe card is being cleaned. In addition, the equipment and manual labor adds additional costs to the task performed. It is desirable to provide a probe card cleaning device and method which overcomes the above limitations and drawbacks of the conventional cleaning devices and methods so that the probe cards may be cleaned more rapidly and effectively while in the prober and it is to this end that the present invention is directed. The cleaning device and method may also be used with other devices. SUMMARY OF THE INVENTION In accordance with the invention, a cleaning medium is provided that will clean the probes of a probe card without removing the probe card from the prober. In particular, the cleaning medium may be placed within the prober similar to a wafer being tested so that the probes of the probe card contact the cleaning medium periodically to remove debris and/or contaminates from the probes. In a preferred embodiment, the cleaning medium may include a substrate that may be shaped like a typical semiconductor wafer that typically fits into the prober. In other embodiments, the substrate may be of various shapes and sizes and thickness. In one embodiment, a ceramic plate or any type of substrate may be used that fits over or replaces the abrasive plate in the prober. The pad may have predetermined mechanical and/or chemical characteristics, such as abrasiveness, density, elasticity, tackiness, planarity, and/or chemical properties, such as being acetic or basic, so that when the probe tips contact the pad surface, the tips of the probes are cleaned and the debris and contaminates are removed from the tips. In another embodiment, the pad may be made of a material so that the probe tips may penetrate into or through the pad, which cleans the debris from the tips. In a preferred embodiment, the substrate may be a semiconductor wafer, ceramic, or any material to which the cleaning pad will attach. In another embodiment, the physical properties of the pad, such as density and abrasiveness, may be predetermined so as to clean the probe element and remove bonded or embedded debris from the probe elements without causing significant damage to the probe elements. In another embodiment, the physical properties of the pad, such as density and abrasiveness, may be predetermined so as to shape or reshape the probe elements during probing on or into the medium. Thus, in accordance with the invention, a cleaning medium for cleaning probe elements in a semiconductor testing apparatus is provided wherein the cleaning medium comprises a substrate having a configuration to be introduced into the testing apparatus during normal testing operation, and a pad, secured to the substrate. The pad has predetermined characteristics, which clean debris from the probe elements and maintain or modify the shape of the probe element when the elements contact or penetrate into or through the pad. In accordance with another aspect of the invention, a method for cleaning the probe elements on a prober or an analyzer is provided wherein the method comprises loading a cleaning medium into the prober, the cleaning medium having the same configuration as the wafers with the semiconductor dies normally tested by the testing apparatus and the cleaning medium having a top surface with predetermined properties, such as abrasiveness, tack, hardness, that clean the probes. The method further comprises contacting the probe elements with the cleaning medium during the normal testing operation in the prober so that any debris is removed from the probe elements during the normal operation of the prober or analyzer. In accordance with another aspect of the invention, a method for maintaining or modifying the shape of the probe elements on a prober or an analyzer is provided wherein the method comprises loading a cleaning medium into the prober or analyzer, the medium having varying density, tack, abrasiveness or other physical characteristics which are optimized for various probe elements of the probe cards. In accordance with another aspect of the invention, the pad may have a particular surface finish such that the prober/tester device is capable of detecting the surface of the cleaning pad. The surface texture may also contribute to the cleaning efficiency of the working surface polymer material. When the prober/tester is capable of detecting the surface of the cleaning pad, then the prober is able to be set into an automatic cleaning mode. In the automatic cleaning mode, the prober/tester will automatically determine when to clean its probe tips, locate the cleaning pad, clean the probe tips on the cleaning pad and then return to testing operations. In one embodiment of the invention, the pad surface may be a matte finish which permits the prober/tester to optically determine the location of the surface of the cleaning pad. In another embodiment of the invention, the pad may be formed from a conductive polymer such that a tester/prober that detects a surface using conductance is able to detect the surface of the cleaning pad. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of an automated testing system that may include the cleaning device in accordance with the invention; FIG. 2 is a top view of the automated testing system of FIG. 1; FIG. 3 is a top view of an embodiment of a cleaning device in accordance with the invention; FIG. 4 is a sectional view taken along line A-A in FIG. 3 of the cleaning device in accordance with the invention; FIG. 5 is a flowchart illustrating a method for cleaning a probe tip in accordance with the invention; FIGS. 6A and 6B are diagrams illustrating another embodiment of the cleaning device in accordance with the invention; FIG. 7 is a flowchart illustrating a method for manufacturing the cleaning device shown in FIGS. 6A and 6B; FIGS. 8A-8C are diagrams illustrating a matte finish cleaning device in accordance with the invention; FIG. 9 is a diagram illustrating a conductive cleaning device in accordance with the invention; and FIG. 10 is a diagram illustrating an automatic prober/tester cleaning method in accordance with the invention. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT The invention is particularly applicable to a cleaning medium for cleaning the probes in a prober and it is in this context that the invention will be described. It will be appreciated, however, that the device and method in accordance with the invention has greater utility, such as cleaning other types of semiconductor processing equipment. The cleaning method can also be used on an analyzer which is a metrology tool used in the routine maintenance of probe cards. FIGS. 1 and 2 are diagrams illustrating a testing system 10 that may be cleaned using the cleaning medium in accordance with the invention. In particular, the system 10 may include a tester 11 electrically connected to a prober machine 12 that may actually apply the probes to the semiconductor wafer or die and test them. The prober machine 12 may further include a prober 13 and an interface head 14 as shown in FIG. 1. The prober machine 12 may also have an abrasion/sanding disk 16, which is typically used to burnish the probe tips, as shown in FIG. 2. The prober may also include a brush attachment that is shown in more detail in U.S. Pat. No. 5,968,282 which is incorporated herein by reference. The prober machine 12 may also include a prober chuck 15 that moves the wafers/dies during the testing process. Instead of the typically removing the prober card in order to clean the probe elements, the cleaning device in accordance with the invention permits the probe elements to be cleaned while the prober is operating. In particular, a cleaning wafer cassette containing the cleaning device in accordance with the invention may be introduced periodically into the testing system in accordance with the invention. Alternatively, a cleaning device in accordance with the invention may be loaded into each cassette with other wafers being tested so that the probe elements are cleaned each time a cassette of wafers is tested. Thus the cleaning medium will clean the probe needles during the normal testing operation of the prober. Now the cleaning medium in accordance with the invention will be described in more detail. FIGS. 3 and 4 are diagrams illustrating an embodiment of a cleaning device 20 in accordance with the invention. In accordance with the invention, the cleaning device 20 may be manufactured using various substrate materials, different size substrates, different shape substrates or without a substrate in some applications. As shown in FIG. 4, the cleaning device 20 may include a substrate 22 and a pad 24 secured or adhered to a surface 25 of the substrate. The substrate may be any material that can support the pad and has sufficient strength to resist breaking when the probes come into contact with the pad and generate a contact force. Thus, the substrate may be plastic, metal, glass, silicon, ceramic or any other similar material. In a preferred embodiment, the substrate 22 may be a semiconductor wafer. The wafer surface 25 onto which the pad is secured or adhered may have a flat mirror finish or a slightly abrasive roughness finish with microroughness of about 1-3 μm. The abrasive finish may burnish/abrade the probe tips during the cleaning process. The pad 24 may be made of a material with predetermined properties that contribute to the cleaning of the probe elements tips that contact the pad. For example, the pad may have abrasive, density, elasticity, and/or tacky properties that contribute to cleaning the probe tips. The abrasiveness of the pad will loosen debris during the scrubbing action and remove unwanted material from the tips. Using a more dense material, the abrasiveness of the pad may round or sharpen the probe tips. The pad may further be used to reshape a flat probe tip into a semi-radius or a radius probe tip. Furthermore, the pad may be used to re-furbish the tip shape of “used” probe cards. Typical abrasives that may be incorporated into the pad may include aluminum oxide, silicon carbide, and diamond although the abrasive material may also be other well known abrasive materials. The abrasive may include spatially distributed particles of aluminum oxide, silicon carbide, or diamond. The tackiness of the pad may cause any debris on the probe tip to preferentially stick to the pad and therefore be removed from the probe tip. In a preferred embodiment, the pad may be made of an elastomeric material that may include rubbers and both synthetic and natural polymers. The elastomeric material may be a material manufactured with a slight tackiness or some abrasive added to the body of the material. The material may have a predetermined elasticity, density and surface tension parameters that allow the probe tips to penetrate the elastomeric material and remove the debris on the probe tips without damage to the probe tip, while retaining the integrity of the elastomeric matrix. In the preferred embodiment, the elastomeric material may be the Probe Clean material commercially sold by International Test Solutions, Inc. The material may have a thickness generally between 1 and 20 mils thick. The thickness of the pad may be varied according the specific configuration of the probe tip. As the one or more probe elements of the prober contact the pad during the normal operation of the prober machine, they exert a vertical contact force to drive the probe element into the pad where the debris on the probe elements will be removed and retained by the pad material. In other embodiments of the cleaning system, the cleaning efficiency of the material can be improved with either a horizontal translation and/or an orbital motion of the cleaning unit during the probe tip cleaning operation. The amount and size of the abrasive material added to the elastomer may vary according the configuration and material of the probe elements to achieve a pad that will remove the debris but will not damage the probe elements. The pad material and abrasiveness may be adjusted during the manufacturing of a pad when the pad is used to reshape, sharpen or refurbish the probe element tips. The same cleaning and reshaping may also be accomplished by the substrate alone. Once the optimal probe tip shape has been established, conventional abrasive methods affect the integrity of the tip shape, probe card planarity and alignment, and, over time, degrade probe card performance and reduce probe card service life. Furthermore, these destructive cleaning methods remove material from the test probe tip and reduce the probe card life by damaging the test probe tip, degrading the electrical performance and compromising any test probe tip shape related properties. In accordance with the invention, the cleaning system and pad not only removes and collects adherent particulates from the test probe contact surface but maintains the shape and geometric properties of the test probe tip contact surface. The insertion of the test probe tips into the cleaning device 20 removes adherent debris from the probe tip length and probe beam without leaving any organic residue that must be removed. Spectral analysis shows no material transfer from the cleaning material onto the contact surface of the test probe. Furthermore, the overall probe card electrical characteristics are unaffected. Now, a method for cleaning a plurality of probe elements in accordance with the invention will be described. FIG. 5 is a flowchart illustrating a method 30 for cleaning a plurality of probes in accordance with the invention. The method accomplishes the goal of removing the debris from the probe tips without removing the probe card from the prober, which increases the productivity of the tester. In step 31, the cleaning device, that may have the same size and shape as typical wafers containing the dies being tested by the tester, may be inserted into a wafer cleaning tray. In accordance with the invention, the cleaning medium may be located in the wafer cleaning tray or one or more cleaning pads may be inserted into one or more cassettes that also contain wafers with semiconductor devices to be tested so that, as each cassette is run through the tester, the cleaning device in the cassette cleans the probe elements. In step 32, the tester is operated and tests the semiconductor dies on the wafers. In step 33, the prober identifies a predetermined number of failures in the dies being tested which indicates that the prober element's may be dirty. In step 34, the cleaning device in accordance with the invention (a wafer) is loaded and aligned with the chuck. In step 35, the probe elements in the tester contact the cleaning device so that the debris is removed from the probe elements or the tips of the probes may be reshaped. As described above, this cleaning step may occur either when the cleaning device is periodically installed from the wafer cleaning tray into the prober or every time from the wafer cassette, or anytime the prober cleans the probe card on the burnishing plate. In step 36, the cleaning is completed and the prober returns to testing the die and wafers. In step 37, the cleaning wafer is returned to the cleaning tray so that the prober machine can continue to test dies. In accordance with the invention, the cleaning device does not interrupt, in any way, the operation of the prober since the cleaning of the probes is accomplished during the normal operation of the testing machine. In this manner, the cleaning device is inexpensive and permits the probe to be cleaned and/or shaped without removing the probe card from the prober. Now, another embodiment of the cleaning device in accordance with the invention will be described. FIGS. 6A and 6B are diagram illustrating a second embodiment of a cleaning device 40 in accordance with the invention. In more detail, the cleaning device 40 may include one or more different layers of material which may clean or sharpen the probe elements as will now be described. Thus, in accordance with this embodiment of the invention, the cleaning pad may be placed on a substrate for use on the abrasive plate in the prober, the prober chuck, analyzer or any other machine. As shown in FIG. 6A, the cleaning device 40 may include a frame 42 that encloses one or more layers of chemical cells 44. The layers in the cleaning device may be made of a material which exhibits acetic or basic chemical properties which may be used to oxidize and/or reduce contaminates on the probe tips. The layers may also be made of materials that induce chemical reactions and/or mechanical actions that remove such contaminates. The removal of the contaminates, such as heavy metals, that may be environmentally hazardous will be trapped on or in the pad so that they will not be dispersed into the air. This embodiment will now be described in more detail with reference to FIG. 6B. FIG. 6B is a diagram illustrating the second embodiment of a cleaning device 40 in accordance with the invention with a probe needle 52 inserted into the layers of the cleaning device in order to clean the probe needle. In more detail, the cleaning device may have a shape of a typical wafer so that it may be used in-line and may further include one or more different layers of material. In particular, the cleaning device 40 may include a substrate 54 having a wall wherein the wall may be constructed of several pieces made of chemically resistant material. The walls may include a bottom portion 56, a middle portion 58 and an upper portion 60 stacked on top of each other with a layer of elastomeric material 61 in between the portions of the wall. The walls of the substrate form a well region into which one or more different layers of chemicals may be placed and these chemicals may etch away materials struck onto the probe needles. A first bottom well 64 of the substrate may be filled with an acid matrix such as acetic acid, as described with reference to FIG. 7 and sealed into the well by a layer 61 of elastomeric material. The chemical matrix may consist of chemicals in any form, solid, liquid, gas, or encapsulated, emulsified, saturated, gelled, or the like, provided the amount of chemical induces the desired reaction. Once the seal is in place, the middle portion of the wall 58 may be positioned and secured to the seal by an adhesive, mechanical, thermal, or like methods to form a second well 66. In the second well 66, a peroxide mixture that gels is placed into the well as described in more detail with reference to FIG. 7, and sealed by a sealing layer 61. Finally, the upper portion 60 is secured to the top seal layer to form the cleaning device in accordance with the invention. During the cleaning operation, the probe needle 52 may penetrate through the two seal layers 61 and thus extend into the acid and peroxide matrix layers in the wells. The acid and peroxide may react with the contaminates on the probe needle to remove heavy metals and the like. In particular, the acid and peroxide matrix may remove the contaminates from the probe needle and the contaminants may be trapped in the cleaning device by the sealing layers 61. Now, a method for manufacturing the cleaning device shown in FIGS. 6A and 6B will be described. FIG. 7 is a flowchart illustrating a method 70 for manufacturing the cleaning device 40 shown in FIG. 6A and 6B. In particular, in step 72, a substrate with a well region is provided. The substrate is typically made of a chemical resistant material such as certain types of plastic. In step 74, the lower cell of the substrate is filled with the appropriate chemicals and sealed using the elastomeric material. In step 76, the upper cell of the substrate is filled with the appropriate chemicals and sealed using the elastomeric material. Thus, a two layer cleaning device in accordance with the invention is formed. In accordance with the invention, however, the cleaning device may have any number of different layers of chemicals wherein each different layer may serve a particular function such as removing a different contaminant from the probe element. The above embodiment is typically used for a system that tests the wafers or one or more dies on a semiconductor wafer prior to being encapsulated into a package. Now, another embodiment of the cleaning device will be described wherein the cleaning device may be used for cleaning the probe elements of a handler or a tester that may be used to electrically test the leads of a packaged integrated circuit. In accordance with another embodiment of the invention, the cleaning device described above may also be used in connection with an handling/testing apparatus that is used to handling and testing integrated circuits (IC) wherein an individual semiconductor die from the wafer described above has been encapsulated into a material, such as plastic. The IC package may have one or more electrical leads extending out from the package that communicate electrical signals, such as a power signal, a ground signal, etc., with the die inside of the package. The testing/handling apparatus may have a plurality of probe elements (similar to the probe card tester described above) that contact the leads of the package and test the electrical characteristics of the packaged IC in a typical manner. Similar to the probe card cleaner embodiment, the cleaning device may be, in a preferred embodiment, a semiconductor shaped substrate with a pad material wherein the probe elements of the handler/tester may contact the pad periodically to remove debris from the tips of the probe elements as described above. The various different materials used for the cleaning device including the multi-layer embodiment may be used with the tester/handler. The size of the cleaning device may be modified slightly to fit the size and shape of the particular tester/handler. In the multi-layer embodiment, a laminate-like structure may be used wherein the cleaning device has a pad/polymer layer on top of a substrate which is on top of another pad/polymer layer, or a first pad/polymer layer, a second pad/polymer layer underneath the first pad/polymer layer and a substrate underneath the second pad/polymer layer, etc.. Thus, in accordance with the invention, the number of pad/polymer/substrate layers may be controlled to provide control of the overall thickness of the cleaning device as well as the compliance of the thickness of the cleaning device relative to the conditioning unit. This multi-layer embodiment would also provide “edge-side” cleaning for the interior of the socket and contactors of the prober. Now, another embodiment of the cleaning pad that permits a tester/prober to operate in an automatic cleaning mode will be described. Most probers have an automatic cleaning mode in which the prober will automatically determine that its probe elements are dirty (using various mechanisms described below) and then perform a cleaning operation as needed. In accordance with the invention, the embodiments of the cleaning pad described below permit the prober to operate in the automatic cleaning mode. Thus, the cleaning pad embodiments described below permit the prober to automatically detect the surface of the cleaning pad (by various mechanisms described below) and therefore clean its probe elements automatically as described below in more detail. Now, two different embodiments of the cleaning device that permits the automatic cleaning of the probe elements will be described. FIGS. 8A-8C are diagrams illustrating a cleaning device 80 in accordance with the invention with a matte surface finish. As shown in FIG. 8A, the cleaning device 80 initially has a first release liner layer 88 that is made of a known non-reactive polymeric film material and preferably made of a polyester (PET) film. The first release liner may have a matte finish or other “textured” features to improve the optical detection of the cleaning device and/or improve cleaning efficiency. A pad layer (working surface polymer) 86 is formed on the first release liner layer 88. The pad layer 86 is then formed on top of the adhesive layer wherein the pad layer is made from an elastomeric material that may include rubbers and both synthetic and natural polymers. The elastomeric material may be manufactured with a slight tackiness or some abrasive particulates added to the body of the material. The material may have a predetermined elasticity, density, and surface tension parameters that allow the tips to penetrate the elastomeric material and remove the debris on the test probe without damage to the test probe tip, the test probe contact surface, or test probe shape, while retaining the integrity of the elastomeric matrix and without material transfer from the cleaning material onto the contact surface of the test probe. Preferably, the pad material may be Probe Clean material that is commercially available from and manufactured by International Test Solutions, Inc. Next, an adhesive layer 84 is formed on the pad layer 86. The adhesive layer is a compound and adheres a pad layer 86 to a substrate 22 (See FIG. 8B) when the cleaning device is applied to a substrate. In one form, the adhesive layer is comprised of a resin or cross-linked compound and can have a tack value of 1 to 300 gram-force. In another form, adhesive layer is comprised of a resin or cross-linked compound that is considered to be permanent, that is, the cleaning material will be damaged before the adhesive layer is compromised. Finally, a second release liner layer 82 (made of the same material as the first release liner layer) is formed on the adhesive layer 84 wherein the-second release liner layer (also known as the back release liner layer) may be subsequently removed to expose the adhesive layer 84. The first release liner layer 88 protects a working surface 89 of the pad layer 86 from debris/contaminants until the cleaning device 80 is ready to be used for cleaning a prober in a clean room. The cleaning device 80 as shown in FIG. 8A may be in the form that is shipped to an entity that uses a prober/tester. Then, as shown in FIG. 8B, the second release liner layer 82 may be removed which exposes the adhesive layer 84. The adhesive layer 84 may then be placed against the substrate 22 to adhere the cleaning device 80 to the substrate. In accordance with the invention, the substrate may be a variety of different materials as described above which have different purposes. For example, the substrate may be a wafer, but it may also be applied to the top of the sanding/abrasion disk (such as that shown in FIG. 1) or other surfaces. As shown in FIG. 8B, the working surface 89 of the cleaning device 80 is still protected from contaminants and debris by the first release liner layer 88. When the user is ready to begin cleaning probe elements with the cleaning device 80 (and the cleaning device 80 is within the clean room with the prober/tester), the user removes the first release liner layer 88 as shown in FIG. 8C which exposes the cleaning pad layer 86 so that the prober may be cleaned. In accordance with the invention, the removal of the first release liner layer 88 leaves the working surface 89 of the cleaning pad layer with a matte finish. In the preferred embodiment, the surface finish, smoothness, texture, and/or surface morphology of the cleaning pad can be obtained, developed, or, imparted to reflect the smoothness, texture, and/or surface morphology of the release liner. Furthermore, the surface finish of the cleaning polymer, as well as, the surface finish of the release liner can be modified by solvent-induced effects. In accordance with the invention, a prober/tester that detects the position of a surface, such as a cleaning device, using light or optical energy to detect the working surface 89 of the cleaning device 80 due to the matte surface so that the cleaning device 80 shown in FIG. 8A-8C permits that prober to be run in an automatic cleaning mode as described in more detail below. For example, the prober may direct optical energy, such as visible light or infrared light or UV light, towards the working surface of the cleaning device and then receive the reflected light from the working surface of the cleaning device. From the received reflected optical energy, the prober is able to accurately determine the location of the working surface of the cleaning device as is well known. In contrast, a typical substrate, such as a wafer, with a mirror finish does not permit the tester/prober to determine the working surface of the substrate due to the reflectivity of the substrate. Now, another embodiment of the cleaning device 80 that permits a prober/tester to operate in an automatic cleaning mode will be described. FIG. 9 is a diagram illustrating a cleaning device 80 in accordance with the invention which is conductive. FIG. 9 illustrates a completed cleaning device 80 wherein the cleaning device 80 is adhered to a substrate 22 and the cleaning device 80 further comprises an adhesive layer 84 and a conductive cleaning pad layer 90. As above, the adhesive layer 84 adheres the cleaning pad layer 90 to the substrate 22. In this embodiment of the invention, the cleaning pad layer 90 is conductive so that a prober/tester that determines the location of a surface using conductance testing is able to accurately locate the working surface 89 of the cleaning pad layer 90. Thus, a prober/tester that performs a conductance test to detect a surface is able to operate in the automatic cleaning mode using the cleaning device 80 shown in FIG. 9. In accordance with the invention, the cleaning pad layer 90 may be made conductive using a variety of different methodologies. For example, the material of the cleaning pad layer 90 may include an additive which makes the cleaning pad layer 90 conductive. The conductive additive or filler may be, for example, conductive carbon-graphite particles or fibers, metal plated abrasive particulates or fibers, metallic particulates or fibers, which make the cleaning pad layer conductive. In the alternative, a well known conductive polymer material, such as polyanilenes, polypyrroles, polythiophenes, or other well known conductive polymer materials, may be used for the cleaning pad layer 90. A conductive element 92 is shown in FIG. 9 and may be implemented in various well known manners. The cleaning devices 80 shown are examples of the different embodiments of the invention which is a cleaning device that permits a prober/tester to detect the working surface of the cleaning device so that the tester/prober device is able to operate in an automatic cleaning mode. It is desirable to operate the prober/tester in the automatic cleaning mode which reduces the involvement of humans (and reduces the errors and contaminants) and also increases the throughput of the prober/tester. Now, an automatic prober/tester cleaning method in accordance with the invention will be described in more detail. FIG. 10 is a diagram illustrating an automatic prober/tester cleaning method 100 in accordance with the invention. In a preferred embodiment, the method is implemented by software code/firmware (a sequence of computer instructions) residing in the prober device or in the tester device that is executed by a well known processor of the tester/prober device. The method may also be implemented using code that is hard-coded into a hardware device such as a microcontroller or other device. In step 102, the tester/prober is set into the automatic cleaning mode. In step 104, the prober performs its testing operations. In step 106, the prober/tester determines if a cleaning is needed. The prober/tester may determine the desirability of cleaning using a variety of methods. For example, the prober/tester may monitor the parameters being determined by the tester and then choose to start a cleaning step when the parameters vary by some predetermined amount from the normal value. In the alternative, the prober/tester might clean at a fixed period rate (a predetermined number of testing operations before a clean operation.) Obviously, the prober/tester may determine the desirability of a cleaning step/process in various ways known to those of ordinary skill in the art. If a cleaning is not needed, then the prober/tester loops back to step 104 and continues testing. If a cleaning is needed, then, in step 108, the prober/tester locates the position of the working surface of the cleaning device in accordance with the invention (using various methods including those described above of optical detection or conductance detection.) Then, in step 110, the cleaning step is performed and the method loops back to step 104 to continue testing. Preferably, the cleaning device in accordance with the invention is located adjacent the tester/prober, such as on the sanding disk 16 shown in FIG. 1 so that a wafer with the cleaning device does not need to be moved into position. Thus, using the cleaning method described above, the throughput of the prober/tester is increased since the prober/tester may rapidly clean its probe elements and then resume testing with minimal delay. In other embodiments of the cleaning system, a permanent adhesive may be used to affix the cleaning polymers onto the polyester substrate. The permanent adhesive prevents the polymer materials from sliding and maintains the integrity of the various material layers during the cleaning operation. The use of this permanent adhesive material better facilitates translational motion during the probe card cleaning operations. The cleaning materials are currently applied onto a polyester film or directly onto a silicon wafer. The materials can also be directly applied to metallic substrates, such as aluminum and stainless, as well as onto ceramic substrates or practically any shape and size. In fact, the cleaning materials can be applied to practically any sort of substrate, within reason. The materials have applicability without a substrate and can be used for non-probe card related contactor cleaning applications. For the Probe Scrub material, different substrates may be used for the abrasive lapping film. The abrasives in the standard lapping film are applied to a polyester backing and then the cleaning polymer is applied across the surface of the lapping film. In addition, “non-standard” substrates for the lapping film (polyester and low temperature epoxy binders for the abrasive particles seem to be the industry standard for abrasive, lapping materials) may be used. For these applications, a lapping film constructed from either a fabric substrate and a metallic foil substrate (or some combination) onto which the cleaning polymer will be applied may be used. Furthermore, a high temperature binder for the abrasive particles of the lapping film may be used. This combination of temperature resistant material layers will facilitate the use of Probe Scrub across a much wider temperature range. While the foregoing has been with reference to a particular embodiment of the invention, it will be appreciated by those skilled in the art that changes in this embodiment may be made without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>This invention relates generally to a medium for cleaning a manual test interface while it is still in the prober. This manual interface is generally referred to as a probe card, which is used in the prober to make an electrical connection between the die on a silicon wafer and the tester so that the functionality of the die may be evaluated. Currently, the method for cleaning the probe card is to remove it from the prober and manually clean the debris from the probe tips. The probe tips need to be cleaned to remove debris from them since the debris reduces the quality of the electrical circuit completed by the contact of the probe tips to any surfaces on a die. The completed electrical circuit is used to evaluate the electrical characteristics of the die by the test apparatus. The degradation of the quality of the electrical circuit caused by the probe tip debris may be interpreted by the test apparatus as a failure of the die under test even though the die is functioning correctly. This false failure of the die results in the rejection or the rework of good die thereby increasing the cost of the final products sold. In the industry, it has been seen that a 1% change in yield from an individual prober can equate to more than $1,000,000 per annum. Therefore, with thousands of probers operating worldwide, the impact to the industry from maintaining clean probes during testing can be very substantial. Individual semiconductor (integrated circuit) devices are typically produced by creating multiple devices on a silicon wafer using well known semiconductor processing techniques including photolithography, deposition, and sputtering. Generally, these processes are intended to create multiple, fully functional integrated circuit devices prior to separating (singulating) the individual devices (dies) from the semiconductor wafer. However, in practice, physical defects in the wafer material and defects in the manufacturing processes invariably cause some of the individual devices to be non-functional, some of which may be repairable. It is desirable to identify the defective devices prior to separating or cutting the dies on the wafer. In particular, some product is actually repairable when the flaws are caught at the wafer lever. Other product may not be repairable but may be used in a downgraded application from the original product. This determination of the product's capabilities (a product definition provided by electrical probe testing) at the wafer level saves the manufacturer considerable cost later in the manufacturing process. In addition, product cost may be reduced if defective devices are identified. To enable the manufacturer to achieve this testing capability a probe card, prober and tester are employed to make temporary electrical connections to the bonding pads, solder or gold bumps or any surface on the chip where connection can be made by making manual contact to that surface. The surface may be on the individual circuit device or on multiple circuit devices when the devices are still part of a wafer. Once the connections between the tester and the circuit device are made, power and electrical signals are transferred from the tester to the device for testing, to determine its functionality and whether the device is accepted or rejected for further processing. Typically, the temporary connections to the device bonding elements are made by contacting multiple electrically conductive probes (often needle like structures) against the electrically conductive bonding elements of the device. By exerting controlled pressure (downwards force on the bonding pads) of the probe tips against the bonding pads, solder balls and/or gold bumps, a satisfactory electrical connection is achieved allowing the power, ground and test signals to be transmitted. The tester and prober need a manual interface to the bonding elements on the die to achieve contact. A probe card having a plurality of probes is used to make the connection with the bonding pads of the semiconductor die. The probes may be cantilever beams or needles or vertical beams. Typically, each probe is an inherently resilient spring device acting as a cantilever beam, or as an axially loaded column. A variation is to mount multiple probes in a spring-loaded support. In a conventional prober, the probe card, and its multiple probes, are held in precise mechanical alignment with the bonding elements of the device under test (or multiple devices, or wafer as the case may be) and the device is vertically translated into contact with the tips of the probes. In the typical prober, the tips of the probes may perform a scrubbing action in which the tip of the probes moves horizontally as it contacts the bonding pad in order to scrub away oxide, or any other material on the pad, that may inhibit the electrical contact between the probes and the bonding pads. Although the scrubbing action improves the electrical contact between the probe tip and the bonding pad, it unfortunately also generates some debris (the scraped up oxide or other debris) that may also prevent the probe tip from making a good electrical contact with the bonding pad. Alternatively, the probe tip may press vertically into the bonding pad, solder or gold bump with sufficient force to penetrate any surface material and establish good electrical contact. The probe tip may become contaminated with contaminates such as aluminum, copper, lead, tin, gold, bi-products, organic films or oxides resulting from the wafer and semiconductor device manufacturing and testing processes. Typically, the debris generated by probing needs to be periodically removed from the probe elements to prevent a build-up which causes increased contact resistance, continuity failures and false test indications, which in turn results in artificially lower yields and subsequent increased product costs. Typically, the entire probe card with the plurality of probes must be removed from the prober and cleaned or abrasively cleaned in the prober. In a typical prober, the probe card can be cleaned several times an hour, several time during a single wafer test, several times during a wafer lot, several times before lot start, and several times after lot start. Also, some operators may clean the probe several times during the initial setup of the test equipment. The process of cleaning in the prober using an abrasive pad burnishes the tips but it does not remove the debris. The burnishing actually causes wear to the probe card by shortening the probe tips. In addition, since it does not remove the debris, and since the debris exhibits a slight electrical charge, it attracts more debris so the probe card will require cleaning more often than the original clean card. Currently the debris from burnishing can be removed manually by means of alcohol and a cotton tip swab, an air gun or an inert gas purge. The probers also utilize a brush unit comprised of natural or synthetic fibers to remove debris from the tips of a probe card. However, the brush operation tends to provide inconsistent cleaning and debris removal. The brush operation has the potential to damage the planarity and alignment of the probes and may push contaminants into the array of the probes or up into the probe guide-plates. Furthermore, some of the particulates during this operation may not be captured within the body of the brush and can become air-borne. This is of particular concern when these particulates are environmentally hazardous. Further details of this known brush unit are shown and described in U.S. Pat. No. 5,968,282. Each method cleans the probes but requires stopping the prober or manual intervention to perform the function. Other contaminates, such as lead and tin, may be removed by abrasive cleaning/burnishing or cleaning the probes with a solution that may typically be an acid, for example. When probe cards which have collected lead and tin are burnished, particulates of lead are released into the air that cause environmental hazards. In addition, the acid solution requires a separate, rather expensive machine that sprays the solution onto the tips in a closed chamber. These typical cleaning processes are expensive since the tester will have down time and a replacement card must be purchased to run while the other probe card is being cleaned. In addition, the equipment and manual labor adds additional costs to the task performed. It is desirable to provide a probe card cleaning device and method which overcomes the above limitations and drawbacks of the conventional cleaning devices and methods so that the probe cards may be cleaned more rapidly and effectively while in the prober and it is to this end that the present invention is directed. The cleaning device and method may also be used with other devices. | <SOH> SUMMARY OF THE INVENTION <EOH>In accordance with the invention, a cleaning medium is provided that will clean the probes of a probe card without removing the probe card from the prober. In particular, the cleaning medium may be placed within the prober similar to a wafer being tested so that the probes of the probe card contact the cleaning medium periodically to remove debris and/or contaminates from the probes. In a preferred embodiment, the cleaning medium may include a substrate that may be shaped like a typical semiconductor wafer that typically fits into the prober. In other embodiments, the substrate may be of various shapes and sizes and thickness. In one embodiment, a ceramic plate or any type of substrate may be used that fits over or replaces the abrasive plate in the prober. The pad may have predetermined mechanical and/or chemical characteristics, such as abrasiveness, density, elasticity, tackiness, planarity, and/or chemical properties, such as being acetic or basic, so that when the probe tips contact the pad surface, the tips of the probes are cleaned and the debris and contaminates are removed from the tips. In another embodiment, the pad may be made of a material so that the probe tips may penetrate into or through the pad, which cleans the debris from the tips. In a preferred embodiment, the substrate may be a semiconductor wafer, ceramic, or any material to which the cleaning pad will attach. In another embodiment, the physical properties of the pad, such as density and abrasiveness, may be predetermined so as to clean the probe element and remove bonded or embedded debris from the probe elements without causing significant damage to the probe elements. In another embodiment, the physical properties of the pad, such as density and abrasiveness, may be predetermined so as to shape or reshape the probe elements during probing on or into the medium. Thus, in accordance with the invention, a cleaning medium for cleaning probe elements in a semiconductor testing apparatus is provided wherein the cleaning medium comprises a substrate having a configuration to be introduced into the testing apparatus during normal testing operation, and a pad, secured to the substrate. The pad has predetermined characteristics, which clean debris from the probe elements and maintain or modify the shape of the probe element when the elements contact or penetrate into or through the pad. In accordance with another aspect of the invention, a method for cleaning the probe elements on a prober or an analyzer is provided wherein the method comprises loading a cleaning medium into the prober, the cleaning medium having the same configuration as the wafers with the semiconductor dies normally tested by the testing apparatus and the cleaning medium having a top surface with predetermined properties, such as abrasiveness, tack, hardness, that clean the probes. The method further comprises contacting the probe elements with the cleaning medium during the normal testing operation in the prober so that any debris is removed from the probe elements during the normal operation of the prober or analyzer. In accordance with another aspect of the invention, a method for maintaining or modifying the shape of the probe elements on a prober or an analyzer is provided wherein the method comprises loading a cleaning medium into the prober or analyzer, the medium having varying density, tack, abrasiveness or other physical characteristics which are optimized for various probe elements of the probe cards. In accordance with another aspect of the invention, the pad may have a particular surface finish such that the prober/tester device is capable of detecting the surface of the cleaning pad. The surface texture may also contribute to the cleaning efficiency of the working surface polymer material. When the prober/tester is capable of detecting the surface of the cleaning pad, then the prober is able to be set into an automatic cleaning mode. In the automatic cleaning mode, the prober/tester will automatically determine when to clean its probe tips, locate the cleaning pad, clean the probe tips on the cleaning pad and then return to testing operations. In one embodiment of the invention, the pad surface may be a matte finish which permits the prober/tester to optically determine the location of the surface of the cleaning pad. In another embodiment of the invention, the pad may be formed from a conductive polymer such that a tester/prober that detects a surface using conductance is able to detect the surface of the cleaning pad. | 20040416 | 20070410 | 20050106 | 96791.0 | 1 | HOLLINGTON, JERMELE M | CLEANING SYSTEM, DEVICE AND METHOD | SMALL | 1 | CONT-ACCEPTED | 2,004 |
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10,825,916 | ACCEPTED | Bone fixation system and method of implantation | Disclosed is a bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship. In one embodiment, the device comprises a first member connectable to a first vertebra and a second member connectable to a second vertebra and interconnected with the first member. The first and second members are movable relative to one another across a range of motion. An adjustor member transitions between a first state and a second state, wherein the range of motion between the first member and second member spans a first distance when the adjustor member is in the first state, and wherein the range of motion between the first member and second member spans a second distance when the adjustor member is in the second state. | 1. A bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; a second member connectable to a second vertebra and interconnected with the first member, wherein the first and second members are movable relative to one another across a range of motion; an adjustor member that transitions between a first state and a second state, wherein the range of motion between the first member and second member spans a first distance when the adjustor member is in the first state, and wherein the range of motion between the first member and second member spans a second distance when the adjustor member is in the second state. 2. A device as in claim 1, wherein the first distance is less than the second distance. 3. A device as in claim 1, further comprising at least one elongate rod interconnecting the first member and the second member. 4. A device as in claim 1, wherein the range of motion is linear. 5. A device as in claim 1, wherein the first member includes a distraction screw coupler that permits the first member or the first vertebra to be coupled to a distraction screw while the first member is connected to the first vertebra. 6. A device as in claim 1, wherein the distraction screw coupler comprises a borehole sized to receive therethrough a distraction screw. 7. A device as in claim 6, wherein at least a portion of the borehole can mate with a portion of the distraction screw. 8. A device as in claim 1, wherein the first member includes a modular coupler that can mate with a second bone fixation device. 9. A device as in claim 1, wherein the range of motion is curved. 10. A bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; a second member connectable to a second vertebra and interconnected with the first member, the first and second members being movable relative to one another; an adjustor member that can be adjusted to vary the degree of movement of the first member relative to the second member, wherein the degree of movement spans a first range when the adjustor member is in an first state and wherein the degree of movement spans a second range when the adjustor member is in a second state. 11. A bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; a second member connectable to a second vertebra and interconnected with the first member, the first and second members being movable relative to one another; means for adjusting the range of motion of the first member relative to the second member, wherein the range of motion spans a first distance or a second distance. 12. A bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; a second member connectable to a second vertebra and interconnected with the first member, wherein the second member includes a distraction screw coupler that permits the second member or the second vertebra to be coupled to a distraction screw while the second member is connected to the second vertebra. 13. A device as in claim 12, wherein the first member includes a distraction screw coupler that permits the first member or the first vertebra to be coupled to a distraction screw while the first member is connected to the first vertebra. 14. A device as in claim 12, wherein the distraction screw coupler comprises a borehole sized to receive therethrough a distraction screw. 15. A device as in claim 14, wherein at least a portion of the borehole can mate with a portion of the distraction screw. 16. A device as in claim 12, wherein the second member includes a modular coupler attachable to a second bone fixation device. 17. A device as in claim 12, wherein the first and second members are movable relative to one another across a range of motion, and further comprising: an adjustor member that transitions between an first state and a second state, wherein the range of motion between the first member and second member spans a first distance when the adjustor member is in the first state, and wherein the range of motion between the first member and second member spans a second distance when the adjustor member is in the second state. 18. A bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; a second member connectable to a second vertebra and interconnected with the first member, wherein the second member includes an interface configured to be modularly attached to a second bone fixation device. 19. A device as in claim 18, wherein the interface comprises a borehole extending through the first member, the borehole configured to mate with at least a portion of the second bone fixation device. 20. A device as in claim 18, wherein the borehole is configured to receive a distraction screw such that the second member or the first vertebra can be coupled to a distraction screw while the second member is connected to the second vertebra. 21. A device as in claim 18, wherein the first member includes an interface configured to be modularly attached to a third bone fixation device. | CROSS-REFERENCES TO RELATED APPLICATIONS This application claims priority to co-pending U.S. Provisional patent application No. 60/463,805 filed on Apr. 18, 2003. Priority of the aforementioned filing date is hereby claimed, and the disclosure of the Provisional Patent Application is hereby incorporated by reference in its entirety. BACKGROUND This disclosure is directed at skeletal bone fixation systems, and more particularly to a fixation device and method for retaining vertebrae of a spinal column in a fixed spatial relationship. Bone fixation systems are used to adjust, align and maintain the spatial relationship(s) of adjacent bones or bony fragments after surgical reconstruction of skeletal segments. Such systems may be comprised of bone distraction devices, skeletal bone fixation devices, bone screws and/or bone cables, and any additional instruments needed for implant placement. Whether for degenerative disease, traumatic disruption, infection or neoplastic invasion, surgical reconstructions of the bony skeleton are common procedures in current medical practice. Regardless of anatomical region or the specifics of the reconstructive procedure, many surgeons employ an implantable skeletal fixation device to adjust, align and maintain the spatial relationship(s) of adjacent bones or bony fragments during postoperative healing. These devices are generally attached to the bony elements using bone screws or similar fasteners and act to share the load and support the bone as osteosynthesis progresses. Available systems used to fixate the cervical spine possess several shortcomings in both design and implantation protocols. These devices are manufactured and provided to the surgeon in a range of sizes that vary by a fixed amount. This mandates that a large number of different sizes must be made and inventoried—adding to cost for manufacturer, vendor, and end user (hospitals). More importantly, the pre-manufactured devices may not precisely fit all patients forcing surgeons to choose between a size too small or too large. Current cervical systems are not modular, and will not permit addition of one fixation device to another for extension of the bony fusion at a future date. It is accepted that fusion of a specific spinal level will increase the load on, and the rate of degeneration of, the spinal segments immediately above and below the fused level. As the number of spinal fusion operations have increased, so have the number of patients who require extension of their fusion to adjacent levels. Currently, the fixation device must be removed from the spine and replaced with a longer device in order to extend the fusion to adjacent levels. This surgical procedure necessitates re-dissection through the prior, scarred operative field and substantially increases the operative risk to the patient. Further, since mis-alignment of the original device along the vertical axis of the spine is common, proper implantation of the replacement often requires that the new bone screws be placed in different bone holes. The empty holes that result may act as stress concentration points within the vertebral bodies, as would any empty opening or crack within a rigid structural member, and lead to bone fracture and subsequent device migration. Current systems may provide fixation that is too rigid. Since bone re-absorption at the bone/graft interface is the first phase of bone healing, fixation that is too rigid will not permit the bone fragments to settle and re-establish adequate contact after initial bone absorption. This process will lead to separation of the bony fragments and significantly reduce the likelihood of bony fusion. Unsuccessful bone fusion may lead to construct failure and will frequently necessitate surgical revision with a second operative procedure. Benzel (U.S. Pat. No. 5,681,312) and Foley (patent application Pub. No. US2001/0047172A1) have independently proposed bone fixation systems designed to accommodate bone settling. In either system, however, bony subsidence causes one end of the device to migrate towards an adjacent, normal disc space. This is highly undesirable since, with progressive subsidence, the device may overly the disc space immediately above or below the fused segments and un-necessarily limit movement across a normal disc space. Clearly, accommodation of bone settling at the end of the fixation system is a sub-optimal solution. The implantation procedures of current fixation systems have additional shortcomings. Distraction screws are used during disc removal and subsequent bone work and these screws are removed prior to bone plate placement. As is known to those skilled in the art, the distraction screws are mounted into the bone and used to separate the bones and provide access to the space therebetween. After the distraction screws are removed, the resulting empty bone holes created by removal of the distraction screws can interfere with proper placement of the bone screws used to anchor the device and predispose to poor alignment along the long axis of the spine. This is especially problematic since the surgical steps that precede device placement will distort the anatomical landmarks required to ensure its proper alignment, leaving the surgeon with little guidance during implantation. For these reasons, bone fixation devices are frequently placed “crooked” in the vertical plane and often lead to improper bony alignment. The empty bone holes left by the removal of the distraction screws also act as stress concentration points within the vertebral bodies, as would any empty opening or crack within a rigid structural member, and predispose them to bone fracture and subsequent device migration. Improper fixation device placement and bony fractures can significantly increase the likelihood of construct failure and lead to severe chronic pain, neurological injury, and the need for surgical revision with a second procedure. While many vertebral fixation systems use bone plates, some systems employ longitudinal rods to connect and fixate the vertebra bodies. A number of these devices have been illustrated in U.S. Pat. No. 5,147,360, 5,152,303, 5,261,911, 5,380,324, 5,603,714, 5,662,652, 5,683,391 and 6,214,005. They share the shortcomings enumerated above and exhibit additional limitations of their own. Rod-based systems are usually larger and more bulky than plate-based systems, making these devices difficult to apply in regions with limited space such as the anterior aspect of the cervical spine. Further, these devices often require the assembly of multiple segments before implantation and are notoriously cumbersome to use. For those reasons, many surgeons will limit their use of rod-based fixation devices in general and avoid them altogether in regions with limited space, such as the anterior aspect of the cervical spine. In view of the proceeding, it would be desirable to design an improved rod fixation system and placement protocol. The new device desirably provides the reliable bone fixation characteristic of rod-based systems as well as address the shortcomings enumerated above. The device is desirably of variable length and able to accommodate any length within a pre-defined range. It is desirably capable of accommodating bone settling at the level of bony subsidence and not encroach upon normal, adjacent disc spaces. The device desirably readily permits extension of the fusion at a future without requiring device removal. And, unlike prior art, the device desirably requires no intra-operative assembly, provides ease of use and is sufficiently compact so as permit application within the anterior aspect of the cervical spine. SUMMARY Disclosed is a modular distraction screw and a rod-based bone fixation system. The distraction screw is placed as the first step of surgery when all relevant landmarks are still intact and used for the bone work prior to device placement. After completion of the bone work, a proximal end of the distraction screw is detached, leaving one or more distal segments still implanted in the upper-most and lower-most vertebral bodies. The distal segments are used to guide the bone fixation device into the correct placement position and serve to hold it stationary while the bone screws are placed. Since the distraction screws were placed with intact surgical landmarks, use of the distal segments to guide the device significantly increases the likelihood of its proper placement. In addition, this placement method leaves no empty bone holes to serve as stress concentration points and further weaken the vertebral bodies. In one embodiment, the bone fixation device includes two sliding components, with one component rigidly affixed onto the vertebral body above the fused space and the other affixed onto the vertebra below. The rod-based sliding segment of each sliding component permits movement along the longitudinal axis of the spine but limits movement in all other planes. A third component comprised of an adjustor component is used to control the range of motion between the first and second sliding components. The relationship between the third, adjustor component and one of the sliding components will determine the extent of variation permitted in the fixation device's overall length. The third component can be locked or unlocked to control the range of motion. When the third component is locked, movement between it and the second sliding component determines the extent of bony subsidence permitted. These design features collectively allow development of a variable length rod-based fixation device that is capable of accommodating bony subsidence at the level of the settling bone, and not at the end of the device. A modular coupler is placed at either end of the device, permitting extension of the fusion at a later date without device removal. The extension is started by connecting a modified distraction screw to the coupler at the end of the device immediately adjacent to the disc to be removed. A modular distraction screw is inserted into the vertebral body on the other side of the diseased disc space. Alternately, a conventional, one-piece distraction screw (rather than the modular distraction screw described herein) can be used to distract the vertebra during discectomy. The distraction screws are then used to distract and open the intervening disc space. A discectomy and subsequent fusion are performed within that disc space. After completion of the bone work, the modified distraction screw is removed leaving the bare coupler on the end of the fixation device. The proximal segment of the distraction screw is also removed leaving the distal segment attached to the adjacent vertebral body. An extension device is used to span the space between the distal segment of the distraction screw on the adjacent vertebra and the end-coupler on the original device. In this way, the fusion is extended and the newly fused segment is fixated without removal of the original fixation device. Further, the end-coupler can used to correct any improper (“crooked”) placement of the original plate by rotating the extension piece into the true vertical. The rod-based bone fixation system described herein provides ease of use, reliable bone fixation, modular design, accommodation of bone settling, and the ability to interact with an implantable distraction screw. These designs maximize the likelihood of proper device placement, avoid maneuvers that weaken the vertebral bodies, address all shortcomings enumerated above, and provide a substantial advantage over the current and prior art. In one aspect, there is disclosed is a bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; a second member connectable to a second vertebra and interconnected with the first member, wherein the first and second members are movable relative to one another across a range of motion; and an adjustor member that transitions between a first state and a second state, wherein the range of motion between the first member and second member spans a first distance when the adjustor member is in the first state, and wherein the range of motion between the first member and second member spans a second distance when the adjustor member is in the second state. In another aspect, there is disclosed a bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; a second member connectable to a second vertebra and interconnected with the first member, the first and second members being movable relative to one another; and an adjustor member that can be adjusted to vary the degree of movement of the first member relative to the second member, wherein the degree of movement spans a first range when the adjustor member is in an first state and wherein the degree of movement spans a second range when the adjustor member is in a second state. In another aspect, there is disclosed a bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; a second member connectable to a second vertebra and interconnected with the first member, the first and second members being movable relative to one another; and means for adjusting the range of motion of the first member relative to the second member, wherein the range of motion spans a first distance or a second distance. In another aspect, there is disclosed a bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; and a second member connectable to a second vertebra and interconnected with the first member, wherein the second member includes a distraction screw coupler that permits the second member or the second vertebra to be coupled to a distraction screw while the second member is connected to the second vertebra. In another aspect, there is disclosed a bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; and a second member connectable to a second vertebra and interconnected with the first member, wherein the second member includes an interface configured to be modularly attached to a second bone fixation device. These and other features will become more apparent from the following description of the embodiments and certain modifications thereof when taken with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an assembled fixation device immediately prior to attachment to the underlying bone. FIG. 2 shows an exploded view of the fixation device. FIGS. 3A-3D show various views of a first component of the fixation device FIG. 4 shows a top view of the first component. FIG. 5 shows a perspective, cross-sectional view of the first component. FIGS. 6A-6D show various views of a second component of the fixation device. FIGS. 7A and 7B show details of a space in the second component of the fixation device, the space sized to receive a third component. FIGS. 8A and 8B show side and perspective views of an adjustment component of the fixation device in an open state. FIGS. 9A and 9B show side and perspective views of an adjustment component of the fixation device in a closed state. FIG. 10 shows a cross-sectional view of the third component coupled to the second component. FIG. 11 shows a top view of the third component coupled to the second component. FIG. 12A shows a cross-sectional view of the third component coupled to the second component along line C-C of FIG. 11. FIG. 12B shows a perspective, cross-sectional view of the third component coupled to the second component along line C-C of FIG. 11. FIG. 13 shows an exploded view of the components of a distraction screw. FIGS. 14A and 14B show cross-sectional views of an assembled distraction screw. FIGS. 15A and 15B show side and top views of a distal segment of the distraction screw. FIG. 16 shows a perspective view of the distal segment of the distraction screw. FIGS. 17 and 18 show enlarged, perspective and side views of a distal region of an elongated body of the distraction screw. FIG. 19 shows the fixation device prior to mounting to a pair of vertebrae. FIG. 20A shows a top view of the fixation device with an adjustment component in an unlocked state. FIG. 20B shows a top view of the fixation device with an adjustment component in a locked state. FIGS. 21A-21B show various views of a modified modular distraction screw in conjunction with a fixation device. FIG. 22 shows a fixation device prior to being coupled to a modular device. FIG. 23 shows a fixation device coupled to a modular device. FIGS. 24A-24B show various views of an offset distraction screw in conjunction with a fixation device. FIG. 25 shows a second embodiment of the fixation device. FIGS. 26A-26C shows a second embodiment of a modular distraction screw for use with the second embodiment of the fixation device. FIGS. 27 and 28 show perspective views of additional embodiments of the fixation device. DETAILED DESCRIPTION Disclosed is a modular bone distraction screw and a rod-based bone fixation device. While they may be used in any skeletal region, these devices are well adapted for use in the spine. Exemplary embodiments of the fixation device, distraction screw and the method of use will be illustrated in this region. Bone Fixation Device FIG. 1 is a perspective view of a bone fixation device 5 configured to retain bone portions such as cervical vertebra of a spinal column in a desired spatial relationship. FIG. 1 shows the device 5 in an assembled state and mounted on a spinal column C and interconnecting a first cervical vertebra V1 and a second cervical vertebra V2. FIG. 2 shows the device 5 in an exploded state. For clarity of illustration, the vertebrae are represented schematically and those skilled in the art will appreciate that actual vertebrae include anatomical details not shown in FIG. 1. With reference to FIGS. 1 and 2, the device 5 includes a first component 20, a second component 30, and one or more adjustor components 40, which are described in more detail below. The first component 20 includes one or more elongate rods 210 that extend along a longitudinal direction. The device 5 further includes a plurality of fasteners, such as bone screws 32, that can be used to fasten the first component 20 and second component 30 to a bone such as the cervical vertebrae V1 and V2. The bone screws 32 may be of any known design that is appropriate for fixation of and implantation into human bone. In addition, the device 5 includes at least one distraction screw 10 for coupling to each of the components 20 and 30, as described in detail below. The bone screws 32 include a head and a shank portion and are used to retain the device 5 against one or more vertebra. The distraction screws 10 are used to distract the vertebra prior to installation of the device 5 and can also be used as a guide for positioning the device 5 on the vertebrae. The components 20 and 30 are configured to slidingly move relative to one another. In one embodiment, the component 30 slides along elongate rods 210 that extend from the first component 20 such that the component 30 can slide along a span, or degree, of linear movement. Alternately, the rods 210 can have a curvature to provide a curved range of movement. The adjustor component 40 can be manipulated to control the degree of movement that is allowed between the components 20 and 30. As described below, the adjustor component 40 can transition between two or more states that control the range of motion of the first component relative to the second component. When the adjustor component is in an open, or unlocked, state, the first and second components can move across a first range of motion relative to one another. When the adjustor component is in a closed, or locked, state, the first and second components can move across a second range of motion relative to one another. In one embodiment, the “range of motion” comprises linear and sliding movement that spans a predetermined distance. The linear movement can be in the longitudinal direction, which corresponds to the longitudinal axis of the spinal column. In one embodiment, the range of motion is a non-zero value both when the component 40 is in the unlocked or locked state. Each of the components 20 and 30 of the device 5 includes an interface, such as a borehole, that can receive or that can matingly engage with a distraction screw, as described below. The borehole permits an additional distraction screw to be attached to the underlying vertebra and/or the device 5 without removing the device 5 from the vertebra. The “additional” distraction screw is a distraction screw different from the distraction screw that was originally used in the vertebra. The device 5 includes a modular aspect that permits the device 5 to be modularly attached to a second device, such as, for example, a coupler to a second bone fixation device, while the device 5 is attached to a spine. The device 5 does not have to be removed from the spine in order to modularly attach the second device to the device 5 in a modular fashion. It should be appreciated that the second device can be a device other than a bone fixation device. When the second device is coupled to a bone fixation device, the modular attachability allows a bone graft to be extended to additional vertebrae without having to remove the original bone fixation device. Component 20 is now described in more detail with reference to FIGS. 3A-3D and FIGS. 4 and 5. FIGS. 3A-3C shows various perspective view of the component 20. The component 20 includes a main body 180 that is generally rectangular in shape. At least one rod 210 extends longitudinally from the main body 180. As best shown in FIGS. 3A and 3C, the main body 180 has an outer surface 303 for facing away from the vertebra V2. As best shown in FIGS. 3B and 3D, the main body 180 also has an inner surface 305 for facing toward the vertebra V1. A pair of side surfaces 307 connect the lateral ends of the outer surface 303 and inner surface 305 to one another. In the illustrated embodiment, the side surfaces 307 are rounded, although it should be appreciated that the side surfaces 307 can also be flat. The main body 180 also has a first end surface 309 (shown in FIGS. 3A and 3B) and rounded, second end surfaces 311 that are interrupted in a central region by a shaft as described further below. It should be appreciated that the main body 180 can have other shapes that are configured for positioning on a cervical vertebra. For example, the inner surfaces 305 can be contoured to conform to the shape of a vertebra on which it will be mounted or the other surfaces can be contoured in a desired manner. Moreover, while not depicted, any component of the device 5 may be further curved in either the vertical or horizontal plane in order to conform to the shape of the bone it is designed to fixate. For example, rod-based bone fixation devices designed to attach onto the anterior aspect of the cervical spine are preferentially convex in both the vertical and horizontal planes. With reference to FIGS. 3A-3D and FIG. 4, one or more fastener screw shafts 313 extend through the main body of the component 20. Each of the fastener screw shafts 313 is sized to receive a corresponding fastener screw 32 (shown in FIGS. 1 and 2). In one embodiment, a screw head engagement structure, such as an annular lip or shelf 315 (shown in FIG. 3A), is located within each fastener screw shaft 313. The head of a fastener screw can engage the shelf 315 and provide a fastening force thereto during fastening of the component 20 to a vertebra. In the illustrated embodiment, the component 20 has two fastener screw shafts 313, each located near a transverse side of the main body. The fastener screw shafts 313 can be aligned with an axis that is oriented in the true vertical plane, or the axis can form an angle with the vertical. For use in the cervical spine, fastener screw shafts 313 can be angled towards each other in the horizontal plane and away from the rods 210 in the vertical plane. The top opening of the fastener screw shafts 313 may be flush with the outer surface 303 surface, can be curved, or can be further recessed so as to form the shelf 315. With reference to FIGS. 3A-3D and FIG. 4, an elongate channel 1022 is located in a central region of the main body 180 between the fastener screw shafts 313. FIG. 5 shows a perspective, cross-sectional view of the component 20 along line E-E of FIG. 4 and provides a more detailed view of the structure of the channel 1022. With reference to FIG. 5, the channel 1022 forms a u-shaped side wall 1025 that defines the periphery of the channel 1022. The inferior region of the side walls 1025 of the channel 1022 can be angled with the true vertical so that the top of each channel has a width that is slightly smaller than the width at the bottom of the channel 1022. Channel 1022 serves to mate with and accommodate a screw head of a corresponding distraction screw, such as the screw head 122 of distal segment of the distraction screw 120 described herein. In this regard, a ledge 1027 can be formed on the side wall 1025 to provide a stepped surface that can be engaged by the head of the distraction screw. It should be appreciated that the shape and configuration of the channel 1022 can be modified into any configuration that is configured to mate with or engage the head of the distraction screw. For example, the channel 1022 can be replaced with a circular hole that is sized to receive a distraction screw. As mentioned, the second end surfaces 311 of the main body 180 are curved, which forms an outwardly extending projection region 1029 on the end of the main body 180, as shown in FIGS. 4 and 5. The projection 1029 can be located along the midline of the main body 180. The projection forms a modular interface, or an end coupler, comprised of a full thickness borehole 182 with sidewall 184 extends through the main body 180 at the projection region 1029. The end coupler provides the device 5 with the ability to modularly couple to another device. The end coupler has a shape that is configured to modularly mate with a complementary-shaped end coupler on a modular device. For example, one or more engagement structures, are located along the wall 184. The engagement structures, such as the spines 186, are configured to engage a modified distraction screw and/or a modular device (as described below) and can have a variety of shapes or structures configured to accomplish this. In the illustrated embodiment, the engagement structures comprise spines 186. While depicted as triangular, the spines may be projections of any geometric configuration, and may occupy part of or all of the height of wall 184. Further, the spines may extend circumferentially around wall 184 or be limited in number and location along the wall (for example, at the ends). Alternatively, wall 184 may be textured or left smooth. In another embodiment, one or more reliefs or cavities can be located on the wall 184, wherein the reliefs or cavities are sized and positioned to receive a correspondingly-shaped portion of a modular device. The borehole 182 is shown in the Figures as intersecting the channel 1022 such that the borehole 182 opens into the channel 1022. However, it should be appreciated that the borehole 182 may be open onto channel 1022 or may separated from it by an additional wall. As mentioned, at least one rod 210 extends outwardly and longitudinally from the main body 180 of the component 20. In the embodiment shown in FIGS. 3-5, two rods 210 extend outwardly from opposed, transverse ends of the component 20. The rods 20 intended to mate and interact with component 30. In this regard, the rods 20 are cylindrical and have a circular cross-sectional shape in order to facilitate such mating. However, it should be appreciated that the rods can have other shapes that can mate with the component 30. The component 30 is now described with reference to FIGS. 6A-6D, which show various perspective views of the component 30. The component 30 includes a main body 351 having a plate like shape. The main body 351 includes a pair of side regions 353 on opposed lateral sides of the component 30. A longitudinally-extending rod shaft 355 (shown in FIGS. 6C and 6D) extends through each of the side regions 353. The rod shafts 355 are sized to receive a corresponding rod 210 of the component 20, as described below. In this regard, each of the rod shafts 355 is positioned so as to be axially aligned with a corresponding rods 210 of the component 20. In one embodiment, the rods 210 are configured to engage with the component 30 in a manner that minimizes the likelihood of the rods 210 disengaging therefrom. In this regard, the end portions of the rods can have diameter that is slightly larger than the entry diameter of the rod shafts 355 so that once the rods 210 are positioned in the rod shafts, the enlarged diameter prevents the rods 210 from inadvertently moving out of the shafts. With reference to FIGS. 6A-6D, the main body 351 of the component 30 has an outer surface 361 for facing away from the vertebra V2. The main body 351 also has an inner surface 363 for facing toward the vertebra V2. A pair of side surfaces 365 define the periphery of the side regions 353 and connect the lateral ends of the outer surface 361 and inner surface 363 to one another. In the illustrated embodiment, the side surfaces 365 are rounded, although it should be appreciated that the side surfaces 365 can also be flat. It should be appreciated that the main body 351 can have other shapes that are configured for positioning on a cervical vertebra. A bar 367 extends outwardly from the main body 351 of the component 30, such as along the midline of the component 30. A pair of projections 369 extend laterally outward from lateral ends of the midline bar 367 such that a projection 369 is spaced from and opposed to each of the side regions 353 containing the rod shafts 355. The projections each contain a hole 371 so that each hole 317 is axially aligned with a corresponding rod shaft 355. The holes 371 are sized to receive the rods 210 therethrough. As in component 20, one or more fastener screw shafts 106 are provided on the main body 351. The central midline bar 367 also has borehole 330 intended to accommodate an additional bone screw 32. As shown in FIG. 1, this screw permits fixation of the device 5 to a bone graft BG. Additionally, an end coupler comprised of a borehole 182 is provided for a distraction screw or for modular connection to another device, as described below. The borehole 182 is equipped with engagement structures, such as spines, as described above with respect to the borehole 182 of component 20. With reference to FIGS. 7A and 7B, a space 340 is formed between each of the projections 369 and the corresponding side region 353. An upper wall 322 extends laterally outward from the bar 367 so as to form a first ledge that overhangs above the space 340 between the projection 369 and the side region 353. A lower wall 328 extends laterally outward from the bar 367 so as to form a second ledge that hangs below the space 340. The upper wall 322 has partial bore 324. Further, upper wall 322 can extend further outward than wall 328 so that the first ledge formed by wall 322 is longer than the second ledge formed by wall 328. Thus, each of the spaces 340 so formed is defined medially by a lateral wall 329 (FIG. 7B), posteriorly by side region 353, anteriorly by projection 369, and is open laterally. As mentioned each projection 369 has a hole 371 so that a corresponding rod 210 can fit through bore hole 371, across space 340 and into rod shaft 355 (FIGS. 6A-6D). FIGS. 8A and 8b show side and perspective views, respectively, of the component 40 of the device 5. The component 40 is sized to fit into the space 340 (FIGS. 7A and 7B) of component 30. The component 40 is configured to adjustably receive and clasp a corresponding rod 210. In the illustrated embodiment, the component 40 comprises a “C”-shaped collar 410 with bore 412 that is sized to receive therethrough a rod 210. The component 40 also includes side handles 420 and 430 that extend outwardly from the collar 410. A threaded screw 440 with an enlarged head 441 is positionable through bores in handles 420 and 430. In one embodiment, the bore in handle 420 is larger in diameter than the outer diameter of screw 440 and the bore in handle 430 is threaded to engage corresponding threads in the screw 440. The screw 440 can be transitioned between an open state and a closed state. In the closed state, shown in FIGS. 9A and 9B, the screw 440 is tightened into the threads in handle 430 such that the head 441 moves downwardly toward the handle 430, which also causes the handle 420 to move downwardly toward the handle 430 and thereby decrease the size of the bore 412 in the collar 410. In the closed state, the screw 440 is tightened sufficiently such that the 30 collar 410 will grasp and secure the rod 210 therein. In the open state, shown in FIGS. 9A and 9B, the screw 440 is un-tightened sufficiently that the head 441 and the handle 420 move away from the handle 430, causing the bore 412 in collar 410 to widen in size. In the open state, the screw 440 is sufficiently un-tightened such that the rod 210 can slide freely through the bore 412 in the collar 410. Thus, when rod 210 is placed into bore 412, it is freely slideable through the bore 412 while the screw 440 is open. When the screw 440 is closed, the rod 210 is locked or clamped within the collar 410 of component 40. As mentioned, the component 40 is sized to fit within each of the spaces 340 of the component 30. FIG. 10 shows a cross-sectional view of the device 5 with each of two components 40 placed within corresponding spaces 340 of the component 30. FIG. 10 shows the screw 440 in an open state. Note that with screw 440 open, the head 441 of the screw 440 fits in and is positioned within partial bore 324 of the component 30. That is, the screw 440 protrudes outward from the component 40 sufficiently so that it is positioned within and interlocks with the partial bore 324 when the screw 440 is open. With rod 210 extending through component 40 and screw 440 open, the interlocking of the head 441 with the bore 324 prohibits the component 40 from moving within the space 340. However, when the screw 440 is open, the rod 210 (and the attached component 20) can slide through the band 410 unhindered relative to component 30 and 40. Thus, components 30 and 40 act as a unitary piece (by virtue of component 40 interlocking with component 30) and can move relative to component 20 across a predetermined distance in the longitudinal direction with the screw 440 open. This is described in more detail below. FIGS. 11, 12 and 13 show the component 40 located in the space 340 of the component 30 and the screw 440 in a closed state. As shown in the top view of FIG. 11, the component 40 is free to slide across a range of distance D1 within the space 340. The distance D1 is at least partially defined by the longitudinal dimension of the space 340. FIGS. 12A and 12B show cross-sectional views of the components 430 and 40 with the component 40 located in the space 340 and the screw 440 closed. When the screw is closed, at least a portion of the component 40 has a height that is less than the height H of the space 340, which is defined by the upper wall 322 and the lower wall. This permits the component 40 to slidingly move within the space 340 along the longitudinal direction (represented by the arrow 1101 in FIG. 11). As described in more detail below, when the rod 210 is placed through the collar 410 and the screw 440 is closed, the collar 410 closes sufficient to fixedly clasp the rod 210. Thus, with the screw 440 closed, the component 40 is locked to rod 210 of component 20 and both components 20 and 40 can move as a unitary piece relative to component 30 within the space 340 along the direction 1101 (FIG. 11). In this way, the fully assembled device with components 20, 30 and 40 permits a certain amount of movement with screw 440 open and a more limited amount of movement with screw 440 closed, as described more fully below. Any component of the device can be made of any biologically adaptable or compatible materials. Materials considered acceptable for biological implantation are well known and include, but are not limited to, stainless steel, titanium, tantalum, other metals, combination alloys, various plastics, resins, ceramics, biologically absorbable materials and the like. It would be understood by one of ordinary skill in the art that any system component can be made of any materials acceptable for biological implantation and capable of withstanding the torque required for insertion and the load encountered during use. Any components may be further coated/made with osteo-conductive (such as deminerized bone matrix, hydroxyapatite, and the like) and/or osteo-inductive (such as Transforming Growth Factor “TGF-B,” Platelet-Derived Growth Factor “PDGF,” Bone-Morphogenic Protein “BMP,” and the like) bio-active materials that promote bone formation. Further, any instrument or device used in implant placement may be made from any non-toxic material capable of withstanding the load encountered during use. Materials used in these instruments need not be limited to those acceptable for implantation, since these devices function to deliver the implantable segments but are not, in themselves, implanted. Distraction Screws FIG. 13 shows an exploded view of the components of a modular distraction screw 10, which is comprised of a distal segment 120 and a removable proximal 130 segment. The proximal segment includes two pieces, as described below. The distal segment 120 has a head portion 122 and a threaded shank portion 124, which can be securely fastened into bone. The proximal segment 130 is comprised of an elongated body 132 and a deployable member 136 comprised of an elongated rod with a proximal head 1362 and threads 128 on a distal end. The elongated body 132 has a smooth-walled internal bore 134 (FIG. 14A) extending through its full length and houses the deployable member 136 within that bore. The deployable member 136 is adapted to be retractably deployed in the bore 134 such that the distal end of the deployable member protrudes beyond the distal end of the internal bore 134. FIG. 14A and 14B show cross-sectional side and perspective views, respectively, of the distraction screw 10 in an assembled state. FIGS. 15A-B and 16 show various views of the distal segment 120 of the modular distraction screw 10. As mentioned, the distal segment 120 is comprised of a threaded shank portion 124 and a head portion 122. The shank portion 124 has threads 126, which can be self-tapping and/or self-drilling. Depending on the particular application, the shank 124 can be of variable lengths and diameter. Further, the threads can be of any design that is well known to be applicable for placement into mammalian bone. The head 122 is circular with hollow central bore 1220. The upper aspect 1222 of the circular head is of uniform diameter but the lower portion 1223 of the head is of progressively greater diameter such that the head has a sloping sidewall below edge 1224. Threads are located within bore 1220 and are complementary to corresponding threads 128 (FIG. 13) of segment 136. The head 122 has slots 1226 intended to engage correspondingly-shaped projections 1322 (FIG. 17) of the distal aspect of the elongated body 132. The slots 1226 are preferably, but not necessarily, four in number and permit the head to collapse inward when centripetal force is applied to the outer wall of the head 122. FIG. 17 shows a perspective view of a distal end of the elongated body 132, looking into the internal bore 134. FIG. 18 shows a side view of the distal end of the elongated body 132. One or more projections 1322 intended to engage slots 1226 of head 122 extend radially inward into the bore 134. As shown in FIG. 14A, the head 122 of the distal segment 120 is sized to fit within the distal region of the bore 134 such that the projections 1322 (FIG. 17) matingly engage the slots 1226 (FIG. 15B) in the distal segment 120. It should be appreciated that the mating engagement between the elongated body 132 and the distal segment 120 can vary in structure and configuration. The deployable member 136 is advanced through bore 134 to engage distal segment 120 using the interaction of the complimentary threads 128 on the deployable member 136 and threads 1225 (FIG. 14B) within the bore 1220 of the distal member 120. The proximal head 1362 of the member 136 has a shape or structure that permits application of rotational force to member 136, which can be used to drive threads 128 and 1225 together and to lock members 132, 136 and distal segment 120 together. The proximal head 1362 is shown having a hex configuration that can be engaged by a wrench. However, while depicted as a hex configuration, any engageable configuration may be used to drive member 136. The coupled proximal segment 130 and distal segment 120 employing the above-described means of engagement provide a modular distraction screw. When fully assembled, the screw will function as a unitary device. In a surgical application, a wrench (not shown) is attached to a tool attachment portion 179 (FIG. 14B) of the elongated body 132, and the distraction screw is positioned at a site of a bone. A rotational force is applied to the portion 179 of the elongated body 132 causing the entire distraction screw 10 to rotate in unison so that the threads 126 of the distal segment 120 engage the underlying bone and the shank 124 is advanced into the bone. After the distraction screw is used to perform the bone work, the proximal segment 130 is detached from distal segment 120. The distraction screw is disassembled into its components by applying a rotational force to head 1362 of member 136 in a direction opposite (usually counter-clock wise) to that required for screw assembly (usually clock-wise). The distal segment is held stationary while threads 128 and 1225 are disengaged by applying a counter force to distal segment 120 using the proximal portion 179 of the elongated body 132. In this way, the proximal segment is removed leaving the distal segment 120 attached to the vertebral bodies. The distal segment provides enhanced structural integrity of the bone by reducing the stress concentration generally expected of an empty opening in a structural member. In addition, leaving the distal segment 120 attached to bone eliminates the robust bone bleeding encountered after removal of current, commercially-available distraction screws and obviates the need to fill the empty hole with a hemostatic agent. The distal segment 120 will also help insure proper device placement. Since placement of the distraction screws is performed as the first step in the surgical procedure, the anatomical landmarks required to ensure proper alignment of the device in the desired anatomical plane are still intact. Alternatively, a conventional one-piece distraction screw can be used to distract the vertebra during discectomy. After the bone work is finished, the conventional distraction screw is removed leaving an empty bone hole. An anchor similar to distal segment 120 is placed into the empty bone hole and guides the placement of the skeletal plate. Placement Protocol The removal of one or more vertebral bodies is accomplished by the step-wise removal of vertebrae until all pathological levels have been addressed. In an initial step of the procedure, the modular distraction screws 10 are placed into the vertebral bodies immediately above and immediately bellow the vertebra to be removed. For example, the screws 10 can be placed in vertebra V1 and V2. The modular distraction screws 10 are then used to distract the vertebra V1 and V2, open the intervening space between V1 and V2, and permit resection of the diseased segment(s) and placement of a bone graft into the evacuated space, as is known to those skilled in the art. After completion of the bone work, the proximal segment of each distraction screw 10 is removed leaving a distal segment 120 attached to each of the vertebral bodies V1 and V2 immediately above and below, as shown in FIG. 19. A graft BG is positioned between the vertebral bodies V1 and V2. With the distal segments 120 of the distraction screws positioned in the vertebra V1 and V2, the assembled device 5 can be mounted to the vertebra V1 and V2. Advantageously, the distal segments 120 do not have to be removed and can be used as initial guideposts for guiding the device 5 onto the vertebra. FIG. 19 shows the assembled device 5 preparing to engage distal segments 120. The fastener screw shafts 106 and 313 in the components 20 and 30, respectively, are positioned and sized to receive bone screws that engage the underlying bony segment in the vertebra V1 and V2. The central channels 1022 in each component 20 and 30 is provided between the two fastener screw shafts 313 and 106. The central channels 1022 provide a space so that the device 5 can interact with the distal segments 120 of the modular distraction screws that have been left attached to vertebra V1 and V2. The device 5 is lowered onto the vertebra so that the distal segments 120 engage into the central channels 1022 and temporarily hold the device 5 against the vertebra. As shown in FIG. 1, the fastener screws 32 can then be inserted into the fastener screw shafts and attached to the bones to thereby fix the device 5 to the vertebra. FIG. 1 shows the device 5 attached to vertebral bodies V1 and V2 and the bone screws 32 in place. The placement process is now described in more detail. With reference to FIG. 19, prior to placing the device onto the distal segments of the distraction screws 120, the distance D between the distal segments 120 attached to the vertebra V1 and V2 is measured and a fixation device 5 of appropriate length is selected based upon that measurement. The device 5 is delivered into the wound fully assembled and with screw 440 in the open position. That is, the components 20, 30 and 40 in an assembled state (as shown for example in FIG. 20A) with the screw 440 of component 40 in an open state. Advantageously, the person that is performing the placement process is not required to attach the components 20, 30 and 40 to one another during the placement process. As mentioned, the components 30 and 40 are fixed relative to one another when the screw 440 is in the open state and can travel across a predetermined distance relative to component 20. In this way, component 30 and 40 are fixed relative to each other but component 20 is freely movable and the device can accommodate a predefined range of sizes. This is described in more detail with reference to FIG. 20A, which shows a top view of the device 5, including the components 20, 30, and 40, with the component 40 in an open state. When screw 440 is in the open state, components 30 and 40 are fixed relative to one another (because the head of screw 440 interlocks in the borehole 324 in component 30). Components 30 and 40 essentially function as a unitary piece 1111 that can travel across a range of motion comprised of a distance R1 relative to component 20. The unitary piece 1111 travels along an axis define by rods 210. The distance R1 is generally defined by the amount of space in the rod shafts 355 through which the rods 210 can move, as shown in FIG. 20A. The rods 210 can slide through the rod shafts up to a point where the tips of the rods abut an internal end of the rod shafts. When the screw 440 is in the open state, the overall length of the device 5 can be varied by moving components 30 and 40 relative to component 20. With reference again to FIG. 19, after the length L of the device 5 is adjusted as described, the device 5 is snapped onto distal segments 120 at each end. The screw heads 122 can briefly collapse permitting the channels 1022 to slip below them. As each head springs back, the device is held between the screw heads 122 and the underlying bone of the respective vertebra. If the device 5 is poorly positioned because of bony irregularity, it can be removed to permit additional bone work. A removal instrument can be used to apply a centripetal force to the side walls of the head 122, causing the side walls to move inward, and permitting the fixation device to be removed. Alternatively, if the device is well positioned, fastener screw shafts 313 and 106 are moved into optimal position for bone screw placement. A screw driver is used to drive distal segment 120 further into the bone, thereby holding the fixation device stationary. The bone screws 32 are then easily placed through the fastener screw shafts into the underlying bone. If compression is desired across the construct, it is applied by bringing component 20 and 30 closer together, such as by using a compression device. The compression is maintained until screws 440 are both tightened and closed. Once tightened, the compression device may be released and the force will be maintained by the fixation device. As mentioned, with the screw 440 closed, components 20 and 40 are locked together (because the components 40 clamps around the rods 210) but both may move relative to component 30 within the confines of space 340. The device can accommodate bony subsidence for a distance allowed within space 340. This is described in more detail with reference again to FIG. 20B. With the screw of component 40 in the closed position, component 40 locks onto the rods 210 of component 20 such that components 20 and 40 essentially act as a unitary piece 1113. The piece 1113 comprised of the components 20 and 40 can move across a range of motion comprised of a distance R2 relative to component 30 with the range of distance R2 being defined by the amount of play in the space 340 in which the component 40 is positioned. The distance R2 is essentially equal to the difference between the length of the component 40 and the length of the space 340 in which component 40 is positioned. In one embodiment, the distance R2 is less than the distance R1. In another embodiment, R1 is less than R2, and in another embodiment, R2 and R1 are substantially equal. Thus, with the component 40 unlocked (corresponding to the screw 440 being open), the components 20 and 30 can move relative to one another across a distance R1 with the rods 210 guiding the movement. With the component 40 locked (corresponding to the screw 440 being closed), the components the components 20 and 30 can move relative to one another across a distance R2, which can differ from the distance R1. Thus, component 40 provides a convenient and efficient means of varying the amount of possible relative movement between components 20 and 30. Extension of the fusion at a future date is easily accomplished without removal of the fixation device 5. Incorporation of the vertebral body immediately above or below into the fusion mass is started by placement of a modular distraction screw 10 into a vertebra (not shown) adjacent to the vertebra V1 or V2. A modified distraction screw 503 (shown in FIGS. 21A-21B) can then be coupled to the device 5 or to one of the vertebra V1 or V2 to which the device 5 is attached. Advantageously, the device 5 does not have to be removed from the vertebra V1 or V2 in order to install the distraction screw in that vertebra. This is because the components 20 and 30 each have a borehole 182 that can accommodate a distraction screw (such as the modified distraction screw 503) therethrough. As shown in FIGS. 21A, the modified distraction screw 503 is used to engage the device 5 and/or the vertebra beneath borehole 182 of the fixation device 5 that is closest to the disc space to be removed. Vertebra V1 is used as an example in FIGS. 21A-21B. The components of that screw and its interaction with the device are illustrated in FIGS. 21A-21B. The modified distraction screw is formed by an elongated body 510 with an internal bore 512 (FIG. 21A) extending through its entire length to distal end portion 516. The internal bore 512 of the elongated body 510 is sized to receive and house an elongated deployable member 530, which is disposed within the internal bore 512. The deployable member 530 is adapted to be retractably deployed in the bore 512 such that a shanked distal end 533 extends beyond an opening 518 at the distal end of the internal bore 512. Threads 532 are located on the distal end 533 of the member 530 and a head 534 is disposed on the other end. The head 534 has a diameter greater than that of the internal diameter of bore 512. A depression 536 is formed within head 534 so as to permit engagement and rotation of the deployable member 530 with a complimentary driver. While depicted as a hexagonal depression intended to receive an Allen's wrench, any alternative means and arrangements for engaging and rotating the deployable member 530 can be employed. Adjacent to the distal end 516 of elongated body 510, spines 518 are placed which are designed to compliment and engage the spines 186 in the sidewall of the borehole 182. The spines on elongated body 510 are used to engage the end coupler immediately adjacent to the disc space to be fused thereby providing an engagement between the distraction screw 503 and the device 5. The threads 532 on the distal end of the deployable member 530 are used to engage the bone surface at the bottom of borehole 182, thus firmly affixing the modified distraction screw 503 to the bone V1. The modified distraction screw 503 and the modular distraction screw previously affixed to the adjacent vertebra are used to distract the vertebral bodies, permitting work on the intervening disc space. When the discectomy and subsequent bone work are finished, the modular distraction screw previously affixed to the adjacent vertebra is separated leaving a distal segment 120 attached to the adjacent vertebra as described above. The modified distraction screw 503 is then removed from the borehole 182, leaving a bare borehole 182, as shown in FIG. 22. A modular device 2202 having an end coupler 2203 can be modularly attached to the device 5 by mating the end coupler 2203 with the borehole 182. The end coupler 2203 has a size and shape that can mate with the borehole 182, such as spines that matingly correspond to the spines in the borehole 182. FIG. 23 shows the end coupler 2203 of the modular device 2202 coupled with the borehole 182. The modular device 2202 is shown only partially in FIGS. 22 and 23, which indicates that the modular device could comprise any of a wide variety of devices. In one embodiment, the modular device 2202 comprises a separate fixation device 5 used to span the distance between the distal segment in the adjacent vertebra and the borehole 182. In this way, the fusion is readily extended to an adjacent level without removal of the original fixation device. Alternately, extension of the fusion can be performed without the use of the modified screw 503 described above. For example, a conventional one-piece distraction screw (without spines) can be used to engage the underlying bone alone through the borehole 182. A modular distraction screw is placed in the vertebral body adjacent to the disc space to be fused. These two distraction screws are used to distract the vertebral bodies, permitting work on the intervening disc space. The remainder of the fusion extension is then performed as described above. Occasionally, a portion of the fixation device 5 abuts the disc space adjacent the vertebra such that placement of the modified distraction 503 screw into the borehole 182 hinders surgical access to the disc space. FIGS. 24A-24B shows an offset modified distraction screw 503 which may be used in this setting and illustrates its placement. The screw components are similar to those described above for the non-offset screw. The offset modified distraction screw 503 includes a bend 2401 that offsets a proximal region of the screw 503 a distance Q from a distal region of the screw. The present invention provides a convenient, easily placed, variable length rod-based bone fixation that is capable of accommodating bony subsidence at the level of the subsiding bone. The device also has a modular design that permits extension of the fusion at a future date. Alternative Designs In the previously-described embodiments, the central channels 1022 opened into the boreholes 182. Since the head 122 of the distal segment 120 of the modular distraction screw 10 can be introduced onto the superior aspect of each central channel through the end opening of the borehole 182, the head 122 need not be collapsible. Thus, as an alternative design, the head 122 can be made solid (not shown). A second embodiment of the device 5 is illustrated in FIG. 25. In this design, a partial thickness end coupler 2511 is located at each end of the fixation device. A projection 1170 is formed by the end coupler and can optionally be placed in the midline of the device 5. The projection 1170 has a central hole 1172 which contains threads. Engagement structures such as spines 1176 may be placed along the top of the projection 1170 to mate with the complimentary spines of the add-on modular attachments. While depicted as triangular, the spines may be projections of any geometric configuration, and may occupy any part of the region of the end coupler 2511. Alternatively, these surfaces may be textured or left smooth. Using the end-coupler 2511, the fusion can be extended at a future date in the same manner as discussed above. This procedure is started by placement of modular distraction screw 10 into the adjacent vertebra. A modified distraction screw is used to engage the end-coupler 2511 of the existing fixation device. The modified distraction screw can be similarly configured as the screw 503 described above with the distal end of the screw modified to mate with the end coupler 2511, such as is shown in FIGS. 26A-26C. The components of the modified distraction screw 503 and the assembled screw 503 are illustrated in FIGS. 26A-26C. As mentioned, the screw is similar to that discussed above. However, the threads at the distal end of the deployable member are designed to engage threads inside the hole 1172 of the end-coupler 2511 and/or engage the underlying bone. The modified distraction screw and the modular distraction screw previously affixed to the adjacent vertebra are used to distract the vertebral bodies, permitting work on the intervening disc space. When the discectomy and subsequent bone work are finished, the modular distraction screw is separated leaving a distal segment 120 attached to vertebral body, as described above. The modified distraction screw is removed leaving a bare end-coupler. A separate fixation device is used to span the distance between the distal segment and the end coupler. In this way, the fusion is readily extended to an adjacent level. The screw can be modified to have an offset configuration, such as was described above with reference to FIGS. 24A-24B. FIG. 27 shows another embodiment of the fixation device 5 wherein the device has a length that is longer than the device 5 described above. The rods 210 have an elongated configuration such that the fixation device 5 covers a larger distance than the previously-described device. The side regions 353 of the component 30 have lengths that are configured to accommodate the lengths of the rods 210. FIG. 28 shows yet another embodiment, wherein a support structure 2810 is interposed between the rods 210 to provide structural support to the rods 210. The support structure 2810 helps to maintain the integrity of the spacing between the rods 210 and reduces the likelihood the rods 210 moving apart or toward one another. Although embodiments of various methods and devices are described herein in detail with reference to certain versions, it should be appreciated that other versions, embodiments, methods of use, and combinations thereof are also possible. Therefore the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein. | <SOH> BACKGROUND <EOH>This disclosure is directed at skeletal bone fixation systems, and more particularly to a fixation device and method for retaining vertebrae of a spinal column in a fixed spatial relationship. Bone fixation systems are used to adjust, align and maintain the spatial relationship(s) of adjacent bones or bony fragments after surgical reconstruction of skeletal segments. Such systems may be comprised of bone distraction devices, skeletal bone fixation devices, bone screws and/or bone cables, and any additional instruments needed for implant placement. Whether for degenerative disease, traumatic disruption, infection or neoplastic invasion, surgical reconstructions of the bony skeleton are common procedures in current medical practice. Regardless of anatomical region or the specifics of the reconstructive procedure, many surgeons employ an implantable skeletal fixation device to adjust, align and maintain the spatial relationship(s) of adjacent bones or bony fragments during postoperative healing. These devices are generally attached to the bony elements using bone screws or similar fasteners and act to share the load and support the bone as osteosynthesis progresses. Available systems used to fixate the cervical spine possess several shortcomings in both design and implantation protocols. These devices are manufactured and provided to the surgeon in a range of sizes that vary by a fixed amount. This mandates that a large number of different sizes must be made and inventoried—adding to cost for manufacturer, vendor, and end user (hospitals). More importantly, the pre-manufactured devices may not precisely fit all patients forcing surgeons to choose between a size too small or too large. Current cervical systems are not modular, and will not permit addition of one fixation device to another for extension of the bony fusion at a future date. It is accepted that fusion of a specific spinal level will increase the load on, and the rate of degeneration of, the spinal segments immediately above and below the fused level. As the number of spinal fusion operations have increased, so have the number of patients who require extension of their fusion to adjacent levels. Currently, the fixation device must be removed from the spine and replaced with a longer device in order to extend the fusion to adjacent levels. This surgical procedure necessitates re-dissection through the prior, scarred operative field and substantially increases the operative risk to the patient. Further, since mis-alignment of the original device along the vertical axis of the spine is common, proper implantation of the replacement often requires that the new bone screws be placed in different bone holes. The empty holes that result may act as stress concentration points within the vertebral bodies, as would any empty opening or crack within a rigid structural member, and lead to bone fracture and subsequent device migration. Current systems may provide fixation that is too rigid. Since bone re-absorption at the bone/graft interface is the first phase of bone healing, fixation that is too rigid will not permit the bone fragments to settle and re-establish adequate contact after initial bone absorption. This process will lead to separation of the bony fragments and significantly reduce the likelihood of bony fusion. Unsuccessful bone fusion may lead to construct failure and will frequently necessitate surgical revision with a second operative procedure. Benzel (U.S. Pat. No. 5,681,312) and Foley (patent application Pub. No. US2001/0047172A1) have independently proposed bone fixation systems designed to accommodate bone settling. In either system, however, bony subsidence causes one end of the device to migrate towards an adjacent, normal disc space. This is highly undesirable since, with progressive subsidence, the device may overly the disc space immediately above or below the fused segments and un-necessarily limit movement across a normal disc space. Clearly, accommodation of bone settling at the end of the fixation system is a sub-optimal solution. The implantation procedures of current fixation systems have additional shortcomings. Distraction screws are used during disc removal and subsequent bone work and these screws are removed prior to bone plate placement. As is known to those skilled in the art, the distraction screws are mounted into the bone and used to separate the bones and provide access to the space therebetween. After the distraction screws are removed, the resulting empty bone holes created by removal of the distraction screws can interfere with proper placement of the bone screws used to anchor the device and predispose to poor alignment along the long axis of the spine. This is especially problematic since the surgical steps that precede device placement will distort the anatomical landmarks required to ensure its proper alignment, leaving the surgeon with little guidance during implantation. For these reasons, bone fixation devices are frequently placed “crooked” in the vertical plane and often lead to improper bony alignment. The empty bone holes left by the removal of the distraction screws also act as stress concentration points within the vertebral bodies, as would any empty opening or crack within a rigid structural member, and predispose them to bone fracture and subsequent device migration. Improper fixation device placement and bony fractures can significantly increase the likelihood of construct failure and lead to severe chronic pain, neurological injury, and the need for surgical revision with a second procedure. While many vertebral fixation systems use bone plates, some systems employ longitudinal rods to connect and fixate the vertebra bodies. A number of these devices have been illustrated in U.S. Pat. No. 5,147,360, 5,152,303, 5,261,911, 5,380,324, 5,603,714, 5,662,652, 5,683,391 and 6,214,005. They share the shortcomings enumerated above and exhibit additional limitations of their own. Rod-based systems are usually larger and more bulky than plate-based systems, making these devices difficult to apply in regions with limited space such as the anterior aspect of the cervical spine. Further, these devices often require the assembly of multiple segments before implantation and are notoriously cumbersome to use. For those reasons, many surgeons will limit their use of rod-based fixation devices in general and avoid them altogether in regions with limited space, such as the anterior aspect of the cervical spine. In view of the proceeding, it would be desirable to design an improved rod fixation system and placement protocol. The new device desirably provides the reliable bone fixation characteristic of rod-based systems as well as address the shortcomings enumerated above. The device is desirably of variable length and able to accommodate any length within a pre-defined range. It is desirably capable of accommodating bone settling at the level of bony subsidence and not encroach upon normal, adjacent disc spaces. The device desirably readily permits extension of the fusion at a future without requiring device removal. And, unlike prior art, the device desirably requires no intra-operative assembly, provides ease of use and is sufficiently compact so as permit application within the anterior aspect of the cervical spine. | <SOH> SUMMARY <EOH>Disclosed is a modular distraction screw and a rod-based bone fixation system. The distraction screw is placed as the first step of surgery when all relevant landmarks are still intact and used for the bone work prior to device placement. After completion of the bone work, a proximal end of the distraction screw is detached, leaving one or more distal segments still implanted in the upper-most and lower-most vertebral bodies. The distal segments are used to guide the bone fixation device into the correct placement position and serve to hold it stationary while the bone screws are placed. Since the distraction screws were placed with intact surgical landmarks, use of the distal segments to guide the device significantly increases the likelihood of its proper placement. In addition, this placement method leaves no empty bone holes to serve as stress concentration points and further weaken the vertebral bodies. In one embodiment, the bone fixation device includes two sliding components, with one component rigidly affixed onto the vertebral body above the fused space and the other affixed onto the vertebra below. The rod-based sliding segment of each sliding component permits movement along the longitudinal axis of the spine but limits movement in all other planes. A third component comprised of an adjustor component is used to control the range of motion between the first and second sliding components. The relationship between the third, adjustor component and one of the sliding components will determine the extent of variation permitted in the fixation device's overall length. The third component can be locked or unlocked to control the range of motion. When the third component is locked, movement between it and the second sliding component determines the extent of bony subsidence permitted. These design features collectively allow development of a variable length rod-based fixation device that is capable of accommodating bony subsidence at the level of the settling bone, and not at the end of the device. A modular coupler is placed at either end of the device, permitting extension of the fusion at a later date without device removal. The extension is started by connecting a modified distraction screw to the coupler at the end of the device immediately adjacent to the disc to be removed. A modular distraction screw is inserted into the vertebral body on the other side of the diseased disc space. Alternately, a conventional, one-piece distraction screw (rather than the modular distraction screw described herein) can be used to distract the vertebra during discectomy. The distraction screws are then used to distract and open the intervening disc space. A discectomy and subsequent fusion are performed within that disc space. After completion of the bone work, the modified distraction screw is removed leaving the bare coupler on the end of the fixation device. The proximal segment of the distraction screw is also removed leaving the distal segment attached to the adjacent vertebral body. An extension device is used to span the space between the distal segment of the distraction screw on the adjacent vertebra and the end-coupler on the original device. In this way, the fusion is extended and the newly fused segment is fixated without removal of the original fixation device. Further, the end-coupler can used to correct any improper (“crooked”) placement of the original plate by rotating the extension piece into the true vertical. The rod-based bone fixation system described herein provides ease of use, reliable bone fixation, modular design, accommodation of bone settling, and the ability to interact with an implantable distraction screw. These designs maximize the likelihood of proper device placement, avoid maneuvers that weaken the vertebral bodies, address all shortcomings enumerated above, and provide a substantial advantage over the current and prior art. In one aspect, there is disclosed is a bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; a second member connectable to a second vertebra and interconnected with the first member, wherein the first and second members are movable relative to one another across a range of motion; and an adjustor member that transitions between a first state and a second state, wherein the range of motion between the first member and second member spans a first distance when the adjustor member is in the first state, and wherein the range of motion between the first member and second member spans a second distance when the adjustor member is in the second state. In another aspect, there is disclosed a bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; a second member connectable to a second vertebra and interconnected with the first member, the first and second members being movable relative to one another; and an adjustor member that can be adjusted to vary the degree of movement of the first member relative to the second member, wherein the degree of movement spans a first range when the adjustor member is in an first state and wherein the degree of movement spans a second range when the adjustor member is in a second state. In another aspect, there is disclosed a bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; a second member connectable to a second vertebra and interconnected with the first member, the first and second members being movable relative to one another; and means for adjusting the range of motion of the first member relative to the second member, wherein the range of motion spans a first distance or a second distance. In another aspect, there is disclosed a bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; and a second member connectable to a second vertebra and interconnected with the first member, wherein the second member includes a distraction screw coupler that permits the second member or the second vertebra to be coupled to a distraction screw while the second member is connected to the second vertebra. In another aspect, there is disclosed a bone fixation device for retaining vertebra of a spinal column in a desired spatial relationship, comprising: a first member connectable to a first vertebra; and a second member connectable to a second vertebra and interconnected with the first member, wherein the second member includes an interface configured to be modularly attached to a second bone fixation device. These and other features will become more apparent from the following description of the embodiments and certain modifications thereof when taken with the accompanying drawings. | 20040415 | 20071106 | 20050106 | 96318.0 | 0 | ARAJ, MICHAEL J | BONE FIXATION SYSTEM AND METHOD OF IMPLANTATION | SMALL | 0 | ACCEPTED | 2,004 |
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10,826,195 | ACCEPTED | Undergarments having finished edges and methods therefor | A method of making a fabric having a finished edge includes providing a fabric having a plurality of fibers with free ends of the fibers at an edge of the fabric, disposing a curable polymer such as silicone over the edge of the fabric so that the curable polymer engages the free ends of the fibers at the edge of the fabric, and, after the disposing step, curing the polymer for finishing the edge of the fabric. The polymer binds the free ends of the fibers to prevent fraying of the fabric. The fabric is cut into a pattern piece for a garment before the step of disposing the curable polymer on the edge of the fabric. | 1. A method of making a fabric having a finished edge comprising: providing a fabric having a plurality of fibers, at least some of said fibers having free ends terminating at an edge of said fabric; disposing a curable polymer over the edge of said fabric so that said curable polymer engages the free ends of said fibers at the edge of said fabric; after the disposing step, curing said polymer for finishing the edge of said fabric. 2. The method as claimed in claim 1, wherein said curable polymer is in contact with the free ends of said fibers. 3. The method as claimed in claim 1, further comprising cutting said fabric before the disposing a curable polymer material step. 4. The method as claimed in claim 3, wherein said cut fabric is a cut pattern piece for a garment, the method further comprising sewing said cut pattern piece to another cut pattern piece for making a garment. 5. The method as claimed in claim 1, wherein said polymer comprises silicone. 6. The method as claimed in claim 1, wherein said polymer comprises a silicone compound having by weight approximately 10-30% silica and 61-90% vinylpoly-dimethylsiloxane. 7. The method as claimed in claim 1, further comprising prior to the disposing a curable polymer step, placing the edge of said fabric over an absorbent material. 8. The method as claimed in claim 7, wherein the edge of said fabric is in contact with said absorbent material during the disposing a curable polymer step. 9. The method as claimed in claim 7, wherein said absorbent material includes an elongated sheet. 10. The method as claimed in claim 7, wherein said absorbent material includes paper. 11. The method as claimed in claim 1, further comprising aligning the edge of said fabric with a dispenser for said curable polymer and dispensing said curable polymer onto the edge of said fabric. 12. The method as claimed in claim 11, wherein said dispenser includes at least one opening for dispensing said curable polymer. 13. The method as claimed in claim 12, wherein said dispenser includes a series of openings for dispensing said curable polymer, at least one of said openings having a different size than at least another one of said openings. 14. The method as claimed in claim 1, wherein the curing said polymer step includes heating said polymer. 15. The method as claimed in claim 14, further comprising monitoring the temperature of said fabric during the curing step. 16. The method as claimed in claim 14, wherein said polymer is heated to approximately 260-280 degrees Fahrenheit. 17. The method as claimed in claim 14, wherein the heating said polymer step includes providing one or more heating stations having heating elements, activating said heating elements to produce heat and placing said fabric into thermal communication with said one or more heating stations. 18. The method as claimed in claim 17, further comprising providing a conveyor element for placing said fabric in communication with said one or more heating stations. 19. The method as claimed in claim 18, wherein said conveyor element has a top surface for supporting said fabric, said top surface having a low coefficient of friction. 20. The method as claimed in claim 19, wherein the top surface of said conveyor element has a non-stick coating. 21. The method as claimed in claim 1, wherein the disposing a curable polymer step comprises disposing a first polymer bead at the edge of said fabric and disposing at least one second polymer bead spaced from said first polymer bead. 22. The method as claimed in claim 21, wherein said at least one second polymer bead is narrower than said first polymer bead. 23. The method as claimed in claim 21, wherein said at least one second polymer bead is adjacent said first polymer bead. 24. The method as claimed in claim 21, wherein the at least one second polymer bead includes a plurality of second polymer beads spaced from one another so that said fabric is exposed between said plurality of second polymer beads. 25. The method as claimed in claim 24, wherein said plurality of second polymer beads extends in a direction parallel to the edge of said fabric. 26. The method as claimed in claim 24, wherein said plurality of second polymer beads extends along a path that mirrors the edge of said fabric. 27. The method as claimed in claim 21, wherein said at least one second polymer bead follows a path selected from the group consisting of paths that are curved, S-shaped, dotted and non-continuous. 28. A method of making cut pattern pieces having finished edges comprising: laying out a spread of fabric; cutting said spread of fabric to provide a plurality of cut pattern pieces, each said cut pattern piece including a plurality of fibers having free ends terminating at an edge of said cut pattern piece; after the cutting step, disposing a curable polymer over the edges of said cut pattern pieces so that said curable polymer engages the free ends of the fibers at the edges of said cut pattern pieces; after the disposing step, curing said polymer for finishing the edges of said cut pattern pieces. 29. The method as claimed in claim 28, wherein said polymer comprises silicone. 30. The method as claimed in claim 28, wherein the disposing a curable polymer step comprises disposing a first polymer bead over the edges of said cut pattern pieces and disposing at least one second polymer bead over each said cut pattern piece adjacent the first polymer beads. 31. The method as claimed in claim 30, wherein said second polymer beads are narrower than said first polymer beads. 32. The method as claimed in claim 30, wherein said at least one second polymer bead includes a plurality of second polymer beads spaced from one another on said cut pattern piece with said fabric being exposed between said plurality of second polymer beads. 33. A garment comprising: a cut pattern piece having an edge, said cut pattern piece including a fabric having a plurality of fibers with free ends that terminate at the edge of said cut pattern piece; and a bead of cured polymer material provided on the edge of said cut pattern piece, wherein said bead of cured polymer material contacts at least some of the free ends of said fibers at the edge of said fabric for finishing the edge. 34. The garment as claimed in claim 33, further comprising: a plurality of second beads of cured polymer material provided on said cut pattern piece adjacent the first bead of cured polymer material, wherein the plurality of second beads are spaced from one another on said cut pattern piece with the fabric of said cut pattern piece being exposed between the second beads. 35. A garment comprising: a cut pattern piece including a fabric having edges and an interior region of said fabric being spaced from the edges; at least one bead of silicone deposited in the interior region of said fabric, wherein said silicone is in contact with said fabric and provides gripping for holding said cut pattern piece in place on a wearer's body. 36. The garment as claimed in claim 35, wherein said garment is selected from the group of garments including undergarments, activewear, shapewear, bathing suits, garments having support panels and garments using compression fabric. 37. The garment as claimed in claim 35, wherein said fabric includes fibers selected from the group consisting of natural fibers including cotton fibers and synthetic fibers including nylon, polyester and spandex fibers. 38. A method of increasing material yield when cutting pattern pieces from fabric comprising: laying a spread of fabric having an unfinished edge; cutting a plurality of pattern pieces from said spread of fabric, wherein at least some of said cut pattern pieces are spaced from the unfinished edge of said spread; disposing a curable polymer material over one or more edges of said cut pattern pieces including the at least some of said cut pattern pieces spaced from the unfinished edge of said spread, wherein said cut pattern pieces include fibers having free ends that terminate at the one or more edges of said cut pattern pieces; curing said polymer material for finishing the one or more edges of said cut pattern pieces. 39. The method as claimed in claim 38, wherein the unfinished edge of said spread is devoid of a knitted-in edge. 40. The method as claimed in claim 38, wherein said polymer comprises silicone. 41. A garment comprising: a cut pattern piece including stretchable fabric made of fibers having free ends terminating at an edge of said cut pattern piece; a polymer material provided on said stretchable fabric in contact with the free ends of said fibers, wherein said polymer material provides a finished edge for said cut pattern piece. 42. The garment as claimed in claim 41, wherein said garment is selected from the group of garments including undergarments, activewear, shapewear, bathing suits, garments having support panels and garments using compression fabric. 43. The garment as claimed in claim 41, wherein the finished edge of said cut pattern piece is devoid of narrow elastic, a folded-over edge, trim and lace. 44. The garment as claimed in claim 41 wherein said garment is an undergarment, and wherein the finished edge of said cut pattern piece is devoid of narrow elastic, a folded-over edge, trim and lace so as to provide a smoother finished edge that is not visible through an outergarment covering the undergarment. 45. The garment as claimed in claim 41, wherein said polymer material provided on said stretchable fabric includes a first polymer bead provided in contact with the free ends of said fibers and at least one second polymer bead in contact with said fabric being spaced from said first polymer bead, wherein said at least one second polymer bead provides gripping for holding said fabric in place over a wearer's body. 46. A garment having a sleek finished edge comprising: a cut pattern piece made of fibers, at least some of said fibers having free ends that terminate at an edge of said cut pattern piece; a cured polymer material provided in contact with the free ends of said fibers at the edge of said cut pattern piece, wherein said cured polymer material provides a sleek finished edge to said cut pattern piece that is devoid of narrow elastic, trim, lace and a folded-over edge. 47. The garment as claimed in claim 46, wherein said cured polymer comprises silicone. 48. The garment as claimed in claim 46, wherein said fabric is stretchable fabric. 49. A method of controlling a stretchable garment utilizing the stretch characteristics of stretchable fabric comprising: providing a spread of stretchable fabric that is more stretchable in a first axial direction and less stretchable in a second axial direction; cutting a pattern piece from said spread, wherein said at least one cut pattern piece has unfinished edges with free ends of fibers at the unfinished edges; disposing a curable polymer over one of the unfinished edges of said cut pattern piece so that said curable polymer engages the free ends of said fibers, wherein the one of the unfinished edges having said curable polymer disposed thereon extends along a third axial direction that crosses the first axial direction; and after the disposing step, curing said polymer for finishing the edge of said cut pattern piece. 50. The method as claimed in claim 49, wherein said curable polymer comprises silicone. 51. The method as claimed in claim 50, wherein the disposing a curable polymer step comprises disposing a first polymer bead at the one of the unfinished edges and disposing at least one second polymer bead spaced from said first polymer bead. 52. The method as claimed in claim 51, wherein said at least one second polymer bead is narrower than said first polymer bead. | BACKGROUND OF THE INVENTION The present invention relates to manufacturing garments and particularly relates to methods for making garments having finished edges. Most garments are made by cutting fabric into pattern pieces and then sewing the cut pattern pieces together to make the garment. Typically, each cut pattern piece has one or more edges that are sewn to the edges of one or more adjacent cut pattern pieces, which forms a seam between the cut pattern pieces. The outer edges of the garment, however, are not sewn to the edges of other cut pattern pieces. As a result, the outer edges are exposed to forces that may fray or tear the fabric. In response to the tearing and fraying problem, the clothing industry has developed methods for finishing the edges of garments, including using narrow elastic, lace, trim and/or a folded over edge. The clothing industry also uses fabric having a knitted-in edge. Although this particular type of fabric provides garments having smoother edges, its use results in relatively low material yields. The most common method for finishing the edge of a cut pattern piece involves using narrow elastic. Referring to FIG. 1A, a cut pattern piece 20 is made of cotton, nylon, polyester, or spandex fibers or any other natural or synthetic fibers commonly used to make garments. As shown in FIGS. 1A and 1B, the cut pattern piece 20 has an outer edge 22 and includes a plurality of fibers 26 having free ends 28 that terminate at the edge 22. As is well known to those skilled in the art, the free ends 28 of the fibers 26 form a rough, outer edge that tends to fray and/or tear as the fabric is used. In order to overcome the above-mentioned fraying problems in clothing such as activewear, shapewear and/or compression garments, most cut pattern pieces have a narrow elastic that is sewn onto the outer edge 22. Referring to FIGS. 2A-2C and 3A-3C, a cut pattern piece 20 has a rough, outer edge 22 with fibers having ends (not shown) that terminate at the edge. Referring to FIGS. 2A and 3A, a narrow elastic 23 is aligned over a top surface 30 of the cut pattern piece 20. Referring to FIGS. 2B-1, 2B-2 and 3B, a flap 25 of fabric adjacent outer edge 22 is folded over the top surface 30 and the narrow elastic is positioned over the flap 25. Referring to FIGS. 23-2, 2C and 3C, the flap 25 and the narrow elastic 23 are held in place by stitching 32 for forming a finished edge 34 on the cut pattern piece. The finished edge including the flap 25 and the narrow elastic 23 has a thickness H1 that is substantially greater than the thickness H2 of the original cut pattern piece 20. As a result, the finished edge is bulky and is likely to be visible through outerwear. As noted above, in most garments, the finished edge is made using a narrow elastic. In some garments, however, the finished edge is made using lace, a fold-over edge, or trim, with and without using a narrow elastic. The presence of the bulky edge (FIG. 2C) is not desirable, particularly when the fabric is used for producing garments such as activewear, shapewear, garments having one or more support panels and garments using compression fabric. The presence of a bulky finished edge is particularly undesirable when the fabric is to be used in undergarments and bathing suits. This is because the finished edge, as shown in FIG. 2C, adds unwanted bulkiness to the garment. For example, a bulky finished edge on an undergarment is undesirable because it may, inter alia, be seen through clothing worn over the undergarment. The bulky finished edge is also less stretchable, so that it will not readily adjust to a wearer's body. This will cause the garment to ride-up and bind to a wearer, causing discomfort. The clothing industry has also developed fabrics having knitted-in edges, whereby relatively complex stitching is used at the edges to avoid the fraying and tearing problems described above. Although garments having knitted-in edges are smoother than garments that use narrow elastic, lace and/or trim, making the fabric for the garments is more expensive. This is because a knitted-in edge requires complex knitting that adds to the cost of making the fabric. In addition, the knitted-in edge provides limitations that adversely affect material yield. Referring to FIG. 4, a spread 20 has a knitted-in finished edge 34 formed along a lower edge thereof. The knitted-in finished edge may also have rubber fibers that are knitted into the fabric to provide gripping to increase the hold of the garment to the body. The spread 20 has a length designated L and a width designated W. In the particular example shown in FIG. 4, the spread has a length L of 252 inches and a width W of 26 inches. A pattern is then used to define a series of pattern pieces 38A-38F. An automatic cutting machine or hand-cutting tool may then be used to cut the pattern pieces 38A-38F. Due to the requirement that each cut pattern piece have a portion of the knitted-in finished edge 34 incorporated therein, only one pattern piece may be cut from each of the respective panels 40A-40F of spread 20. As a result, the fabric in each panel section 40A-40F that is not part of one of the cut pattern pieces 38A-38F is waste material. As is well known to those skilled in the art, wasting material from a spread having a finished edge is undesirable and costly. In the particular spread 20 shown in FIG. 4, the material yield of the spread is 57.13% because the cut pattern pieces 38A-38F utilize 57.13% of the spread, with 42.87% of the spread being unusable waste material. This level of waste is undesirable in the highly competitive and cost-conscious garment industry. In view of the above-described problems, there is clearly a need for garments having finished edges that are not bulky. There is also a need for garments having finished edges that can grip and that do not ride-up over a wearer's body to cause binding. There is also a need for garments having finished edges that are smooth and that do not show through outer garments. Furthermore, there is a need for methods of making garments that improve material yield and reduce waste. SUMMARY OF THE INVENTION In certain preferred embodiments of the present invention, a method of making a fabric having a finished edge includes providing a fabric having a plurality of fibers with free ends of the fibers at an edge of the fabric and disposing a curable polymer over the edge of the fabric so that the curable polymer engages the free ends of the fibers at the edge of the fabric. The method desirably includes, after the disposing step, curing the polymer for binding the free ends of the fibers at the edge of the fabric to the cured polymer. In preferred embodiments, the fabric may be made of cotton, nylon, polyester and spandex fibers or any other natural or synthetic fibers used to make fabric. In certain preferred embodiments, the fabric is cut into pattern pieces before the curable polymer material is disposed on the fabric. Each cut pattern piece may be sewn to one or more other pieces of fabric for making a garment. Although the present invention is not limited by any particular theory of operation, it is believed that cutting the pattern pieces before forming the finished edge will dramatically improve the material yield from a spread, particularly in comparison to techniques using fabric having knitted-in edges. This particular feature will be described and shown in more detail below in FIG. 5 of the present application. Prior to disposing the polymer material, an edge of the cut pattern piece is desirably positioned over an absorbent material, such as a sheet of absorbent paper. In one preferred embodiment, the absorbent paper is a roll of elongated paper that is unrolled onto a conveyor system, with the paper provided on a top surface of the conveyor, between the cut pattern piece and the conveyor. In certain preferred embodiments, at least the edge of the cut pattern piece is in contact with the absorbent material as the polymer is deposited onto the cut pattern piece. Although not limited by any particular theory of operation, it is believed that the absorbent material acts as a shield that prevents the polymer material from coming in direct contact with the conveyor. This shielding action avoids the need to clean or remove polymer from the conveyor. The absorbent material may also assist in the formation of a clean edge of cured polymer material at the edge of the pattern piece. In certain preferred embodiments, the polymer includes silicone. As is well known to those skilled in the art, a silicone is defined as any one of a large group of siloxanes that are stable over a wide range of temperatures. More specifically, silicones are any of a group of semi-inorganic polymers based on the structural unit R2SiO, where R is an organic group, characterized by wide-ranging thermal stability, high lubricity, extreme water repellence and physiological inertness. Silicones are typically used in lubricants, adhesives, coatings, paints, synthetic rubber, electrical insulation and prosthetic replacements for body parts. In one particularly preferred embodiment, the silicone is a compound made up of, by weight, approximately 10-30% silica and 60-90% vinylpolydimethylsiloxane. The method also desirably includes aligning the edge of the cut pattern piece with a dispenser for the curable polymer and dispensing the curable polymer from the dispenser onto the edge of the cut pattern piece. In certain preferred embodiments, the dispenser includes at least one opening for dispensing the curable polymer. In other preferred embodiments, the dispenser includes a series of openings for dispensing the curable polymer, at least one of the openings having a different size than at least another one of the openings. After the polymer has been deposited on the cut pattern piece, the polymer is desirably cured using heat. In one preferred embodiment, one or more heating stations are provided for heating the polymer material previously applied to the cut pattern piece. The cut pattern piece may be placed in thermal communication with the one or more heating elements. In one preferred embodiment, the cut pattern piece may be moved on a conveyor element, such as a conveyor belt, with the absorbent material positioned atop the conveyor and the fabric positioned at least partially on the absorbent material. Each heating station may have one or more heating elements for generating heat. The temperature of the polymer and/or the temperature of the cut pattern pieces may be monitored to insure that the polymer is heated to an adequate temperature to properly cure the polymer. In certain preferred embodiments, the polymer is heated to approximately 260-280 degrees Fahrenheit. In more preferred embodiments, the polymer is heated to approximately 265-275 degrees Fahrenheit. The time limit for heating the polymer may vary. In one preferred embodiment, heating for about one minute cures the polymer on the cut pattern piece. The conveyor element may have a top surface for supporting the cut pattern pieces. In one preferred embodiment, the conveyor element may include a conveyor belt having a top surface for supporting the cut pattern pieces as the pieces move between various stations, i.e. alignment station, disposing polymer station, curing station, etc. In one particular preferred embodiment, the top surface of the conveyor belt may include a material having a low coefficient of friction or a non-stick material such as the material sold under the trademark TEFLON. As a result, there may be no need to provide an absorbent material between the pattern pieces and the conveyor because any polymer deposited on the conveyor may be easily removed from the top surface such as by using a scrapper. The step of disposing a curable polymer on the cut pattern piece may include disposing a first polymer bead over the edge of the pattern piece and disposing at least one second polymer bead adjacent the first polymer bead. The at least one second polymer bead may be narrower than the first polymer bead. In more preferred embodiments, the at least one second polymer bead includes a plurality of second polymer beads. The at least one second polymer bead may include a plurality of second polymer beads spaced from one another, with the fabric of the pattern piece exposed between the plurality of second polymer beads. The one or more second polymer beads may extend in a direction parallel to the edge of the fabric or may extend along a path that mirrors the edge of the fabric. In other preferred embodiments, the polymer may be provided on the pattern piece away from the edge of the pattern piece. In these embodiments, the polymer may provide gripping to prevent the fabric from riding or slipping over the body of a garment wearer. The polymer may be one or more beads that follow an S-shaped or curved pattern. The one or more polymer beads may be continuous or non-continuous, e.g. intermittent deposits of polymer on a fabric. The polymer may also be provided as polymer dots on the fabric. The intermittent polymer deposits may form a matrix of polymer on a fabric. In certain preferred embodiments, the spacing between the polymer beads may be increased for increasing the stretchability of the fabric. In other preferred embodiments, the spacing between the polymer beads may be decreased for increasing the gripping of the fabric. The polymer beads may also be applied over a central region of a fabric to provide gripping at the central region for holding the fabric in place over a body. Another preferred embodiment of the present invention involves cutting a spread. As is well known to those skilled in the art, cutting a spread involves laying down fabric having a desired length in multiple layers. Typically, a spread may include 100 or more layers of fabric. Before cutting the spread into pattern pieces, a particular pattern is selected and applied to the spread. The pattern may be applied through a computer system that analyzes the length of the fabric and determines how to maximize the number of pattern pieces that may be cut from the fabric. The computer system may also control an automatic cutting machine for cutting the fabric into cut pattern pieces. The spread may also be cut by placing a pattern over the spread and cutting the pattern pieces by hand using a cutting tool. In one particular preferred embodiment, a method of making a cut pattern piece for a garment includes providing a spread, and cutting the spread to provide cut pattern pieces, each cut pattern piece including a plurality of fibers having free ends that terminate at an edge of the pattern piece. The method desirably includes after the cutting step, disposing a curable polymer over the edges of the cut pattern pieces so that the curable polymer engages the free ends of the fibers at the edges of the pattern pieces. After the curable polymer is disposed, the polymer is desirably cured for binding the free ends of the fibers at the edges of the pattern pieces to the cured polymer. Each pattern piece having the cured polymer edge may be sewn to at least one other piece of fabric for making the garment. The curable polymer material may be placed on the cut pattern piece by disposing a first polymer bead over the edge of the pattern piece and disposing at least one second polymer bead over the pattern piece adjacent the first polymer bead, whereby the at least one second polymer bead is narrower than the first polymer bead. The at least one second polymer bead may include a plurality of second polymer beads spaced from one another on the pattern piece with a face of the pattern piece being exposed between the plurality of second polymer beads. In another preferred embodiment of the present invention, a section of a garment includes a cut pattern piece having a plurality of fibers with free ends that terminate at an edge of the pattern piece, and a bead of cured polymer material provided over the edge of the pattern piece, the bead of cured polymer material encapsulating at least some of the free ends of the fibers that terminate at the edge of the pattern piece. The pattern piece desirably includes a plurality of second beads of cured polymer material disposed on the pattern piece adjacent the first bead of cured polymer material, whereby the plurality of second beads are spaced from one another on the pattern piece with a face of the pattern piece being exposed between the second beads. The second beads preferably provide gripping which holds the fabric in place over a wearer's body. The present invention provides tremendous benefits over prior art methods of making garments. Specifically, the present invention dramatically increases the material yield from fabric spreads. Prior art methods that use fabric having knitted-in edges require that the finished edge be formed on a spread before the spread is cut to make cut pattern pieces. Because the pattern pieces must be cut from the knitted-in finished edge, a large area of the spread away from the finished edge cannot be used. In contrast to these prior art methods, the present invention enables pattern pieces to be cut from any region of a spread. Thus, the cut pattern pieces do not have to incorporate a knitted-in finished edge, inter alia, because the finished edge of the present invention is preferably formed only after the pattern pieces have been cut. The present invention also enables a spread to have more layers of fabric. When laying a spread of fabric having knitted-in edges, the knitted-in edges are thicker than the rest of the fabric. This limits the number of layers that can be stacked atop one another. Typically, a spread of fabric having knitted-in edges can only be stacked 24 or 48 layers high. In addition, fabric having knitted-in edges is also harder to handle. All of these factors slow down the process of producing pattern pieces having knitted-in edges, which adds to the cost and time needed to manufacture garments. The present invention also provides finished edges that are sleeker and thinner than prior art products having a relatively thick finished edge. As described herein, a silicone bead that finishes an edge is much thinner than the prior art finished edges that use folded-over edges, narrow elastic, trim and/or lace. The silicone beads also provide a garment that grips for preventing the garment from riding over a wearer's body. As a result, the garment will not ride and bind (e.g. constrain). The present invention also provides a garment having stability due to the gripping from the polymer. This stability minimizes the likelihood that the fabric will roll over upon itself, which may result in bunching or binding of the garment. The present invention also provides a finished edge that has more stretch because it does not have a thick finished edge that is formed when using narrow elastic, trim, lace and/or a folded-over edge. In another preferred embodiment of the present invention, a garment includes a cut pattern piece made of a fabric having edges and an interior region of the fabric being spaced from the edges. The fabric may include natural fibers such as cotton fibers or synthetic fibers such as nylon, polyester and spandex fibers. The garment preferably includes at least one bead of silicone deposited in the interior region of the fabric, whereby the silicone is in contact with the fabric and provides gripping for holding the cut pattern piece in place on a wearer's body. The garment may be an undergarment, activewear, shapewear, a bathing suit, a garment having one or more support panels or a garment that uses compression fabric. In another preferred embodiment, a method of increasing material yield when cutting pattern pieces from fabric includes laying a spread of fabric having a bottom edge, cutting a plurality of pattern pieces from the spread of fabric, wherein at least some of the cut pattern pieces do not include the bottom edge of the spread of fabric, and disposing a curable polymer material such as silicone over one or more edges of the cut pattern pieces including the at least some of the cut pattern pieces that do not include the bottom edge of the spread of fabric. In this particular embodiment, the cut pattern pieces may include fibers having free ends that terminate at the one or more edges of the cut pattern pieces. The method also desirably includes curing the polymer material for finishing the one or more edges of the cut pattern pieces. In still another preferred embodiment of the present invention, a garment includes a cut pattern piece made of a fabric with fibers having free ends terminating at an edge of the cut pattern piece, and a polymer material provided on the fabric in contact with the free ends of the fibers, whereby the polymer material provides a finished edge for the cut pattern piece. The fabric may include compression fabric or stretchable fabric such as fabric used in activewear or shapewear. The garment may be an undergarment, activewear, shapewear, a bathing suit, a garment having support panels and a garment using compression fabric. In highly preferred embodiments, the finished edge of the cut pattern piece is devoid of narrow elastic, a folded-over edge, trim and/or lace. As a result, the finished edge of the present invention is not bulky and is able to more easily stretch to adjust to various body dimensions and body movements. As a result, the garment will be less likely to bind to and ride over a wearer's body. In certain preferred embodiments, the polymer material provided on the stretchable fabric includes a first polymer bead provided in contact with the free ends of the fibers and at least one second polymer bead in contact with the fabric, the at least one second polymer bead being spaced from the first polymer bead. The at least one second polymer bead desirably provides gripping for holding the fabric in place over a wearer's body. In yet another preferred embodiment of the present invention, a garment having a sleek finished edge includes a cut pattern piece made of fibers, at least some of the fibers having free ends that terminate at an edge of the cut pattern piece, and a cured polymer material such as silicone provided in contact with the free ends of the fibers at the edge of the cut pattern piece, the cured polymer material providing a sleek finished edge to the cut pattern piece, the finished edge being preferably devoid of a folded-over edge, narrow elastic, trim and/or lace. Due to the absence of the narrow elastic, trim or lace, the finished edge is much thinner than prior art finished edges, and is better suited for stretching, which prevents binding and ride-up. In still another preferred embodiment of the present invention, a method of controlling a stretchable garment utilizing the stretch characteristics of stretchable fabric includes providing a spread of stretchable fabric that is more stretchable in a first axial direction and less stretchable in a second axial direction, and cutting a pattern piece from the spread, wherein the at least one cut pattern piece has unfinished edges with free ends of fibers at the unfinished edges. The method desirably includes disposing a curable polymer over one of the unfinished edges of the cut pattern piece so that the curable polymer engages the free ends of the fibers, wherein the one of the unfinished edges having the curable polymer disposed thereon extends along a third axial direction that crosses the first axial direction, and after the disposing step, curing the polymer for finishing the edge of the fabric. The present invention provides garments that have smoother finished edges than garments that use folded-over edges, narrow elastic, trim and/or lace at the finished edge. As a result, the garments of the present invention will not have bulky finished edges. Moreover, the finished edges of the present invention are more stretchable than the finished edges of garments that use folded-over edges, narrow elastic, trim and/or lace. As a result, the finished edge of the present invention minimizes ride-up and binding. Furthermore, the smooth finished edges or the present invention are less likely to be visible through outer garments than are garments having bulky finished edges made of folded-over edges, narrow elastic, trim or lace. The present invention also improves material yield over techniques that use fabric having knitted-in edges. This is due to the fact that the finished edge is formed after the pattern piece has been cut. As a result, the cut pattern pieces of the present invention do not need to incorporate a particular edge of a spread, such as a knitted-in edge. This enables an operator to cut pattern pieces in regions of a spread that are spaced from the edges of the spread, thereby maximizing material yield. The present invention also improves material yield because an operator has more flexibility to cut a pattern piece from anywhere along a width of a spread. In contrast, methods using fabric with knitted-in edges must cut each pattern piece within the width of one of the panels of a spread. The smaller width of the panels versus an entire spread (20 inches v. 80-120 inches) reduces flexibility when marking patterns on fabric having a knitted-in edge, which further reduces material yield. Moreover, the present invention saves money because it enables the production of garments having smooth finished edges without requiring the used of fabric having costly knitted-in edges. Thus, manufacturers will save money on fabric for making garments. These and other preferred embodiments of the present invention will be described in more detail below. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A shows a panel having an edge. FIG. 1B shows an expanded view of the edge of the panel shown in FIG. 1A. FIGS. 2A, 2B-1, 2C and 3A-3C show a conventional method of making a finished edge on a panel. FIG. 2B-2 shows a perspective view of FIG. 2B-1. FIG. 4 shows a conventional spread having pattern pieces defined in the spread. FIG. 5 shows a plan having pattern pieces defined therein, in accordance with certain preferred embodiments of the present invention. FIG. 6 shows a plan view of a cut pattern piece having an unfinished edge, in accordance with certain preferred embodiments of the present invention. FIGS. 7A-7C show a method of forming a finished edge on the cut pattern piece of FIG. 6, in accordance with certain preferred embodiments of the present invention. FIGS. 8A and 8B show a conventional undergarment having finished edges that are bulky so as to show through outerwear. FIGS. 9A and 9B show an undergarment having finished edges including a polymer bead for binding ends of fibers, in accordance with certain preferred embodiments of the present invention. FIG. 10 shows a cut pattern piece having an unfinished edge. FIG. 11 shows the cut pattern piece of FIG. 10 having a first polymer edge forming a finished edge and second polymer beads forming a gripping surface, in accordance with further preferred embodiments of the present invention. FIG. 12A shows an expanded plan view of the cut pattern piece shown in FIG. 11. FIG. 12B shows a cross-sectional view of the cut pattern piece of FIG. 12A taken along line 12B-12B thereof. FIG. 13 shows a process for forming a finished edge on a cut pattern piece, in accordance with certain preferred embodiments of the present invention. FIG. 14 shows a system for forming a finished edge on cut pattern pieces, in accordance with certain preferred embodiments of the present invention. FIG. 15A shows a plan view of first and second stations of the system shown in FIG. 14. FIG. 15B shows a plan view of third and fourth stations of the system of FIG. 14. FIG. 15C shows a plan view of fourth and fifth station of the system shown in FIG. 14. FIG. 16 shows a bottom view of an applicator device used for applying a curable polymer material to a cut pattern piece, in accordance with certain preferred embodiments of the present invention. FIG. 17A shows a front elevation view of the applicator device of FIG. 16. FIG. 17B shows a side elevation view of the applicator device of FIG. 17A. FIG. 18 shows a spread including a stretchable fabric having a first direction of stretch, in accordance with certain preferred embodiments of the present invention. FIG. 19 shows a pattern piece cut from the spread of FIG. 18. DETAILED DESCRIPTION Referring to FIG. 5, in accordance with certain preferred embodiments of the present invention, a spread 120 has a length designated L and a width designated W. In the particular example shown in FIG. 4, the spread has a length L of 117.56 inches and a width W of 73.50 inches. A pattern is used to define a series of pattern pieces 138A-138L. An automatic cutting machine or hand-cutting tool may be used to cut the pattern pieces 138A-138L. Because the spread 120 has no finished edge, such as a knitted-in edge, the cut pattern pieces may include those cut from the spread at a location away from an edge of the spread. As a result, a greater percentage of the spread may be used to make cut pattern pieces, which will improve the material yield of the spread. In the particular spread 120 shown in FIG. 5, the material yield of the spread is 86.70% because the cut pattern pieces 138A-138L utilize 86.70% of the spread 120, with 13.3% of the spread being unusable waste material. The 86.70% material yield is a tremendous improvement over the 57.13% material yield described in conjunction with the FIG. 4 prior art embodiment that uses fabric having a knitted-in edge. Thus, the present invention saves money by increasing material yield. The present invention also saves money because it obviates the need to use fabric having knitted-in edges, thereby saving on the cost of materials. The present invention is also more economical because it allows more layers of fabric to be stacked in the spread (i.e. 100-200 layers) before cutting the spread, which results in more cut pattern pieces being produced at a faster rate. In contrast, a spread of knitted-in fabric can only be stacked about 24-48 layers high before cutting, because the knitted-in edge is thicker than the remaining portion of the fabric. The thicker edge makes one edge of the spread higher than the other edges of the spread. Referring to FIGS. 6 and 7A-7C, in certain preferred embodiments of the present invention, a cut pattern piece 120 is made of a plurality of fibers 126 having free ends 128 that terminate at an edge 122 of the pattern piece. In order to prevent the free ends 128 of the fibers 126 of the pattern piece from fraying or tearing, a silicone bead is deposited in contact with a top surface 130 of the cut pattern piece 120, adjacent the edge 122 of the pattern piece. As shown in FIGS. 7A and 7B, the silicone material 162 is deposited in contact with the first surface 130 and the edge 122 of the cut pattern piece. As shown in FIG. 7C, the silicone 162 engages and/or contacts the free ends 128 of the fibers 126. Although the present invention is not limited by any particular theory of operation, it is believed that the silicone 162 at least partially encapsulates and/or contacts to the free ends 128 of the fibers 126 so as to bind the free ends of the fibers to the silicone, which prevents the edge 122 of the pattern piece 120 from fraying or tearing. As a result, the pattern piece does not require a finished edge that includes narrow elastic, trim, lace, folded-over edge or a knitted-in finished edge. Furthermore, a spread 120 is preferably cut into pattern pieces 138A-138L (FIG. 5) before applying the silicone material 162 at the edge 122. The ability to cut the spread into cut pattern pieces before forming the silicone finished edge provides a tremendous cost savings over prior art methods because it improves material yield. Thus, one particular benefit of the present invention is that it provides an increased material yield from fabric spreads. In addition, providing a finished edge of silicone reduces the thickness of the pattern piece at the finished edge. In certain preferred embodiments, the thickness of the finished edge including the silicone bead is 1/16 inch, which is significantly thinner than the prior art finished edges using narrow elastic (FIG. 2c), lace, trim or folded-over edges, which provides thicker finished edges of 1/8 inch or greater. FIGS. 8A and 8B show a conventional undergarment 164 having bulky, finished edges 166. Due to the thickness of the bulky edges 166, the undergarment may be visible through outerwear. FIGS. 9A and 9B show an undergarment 164′ having a silicone finished edge that is made using the inventive process described herein. As shown in FIG. 9A, after a pattern piece has been cut, a silicone material 162 is deposited at the edge 122 of the piece. The combined thickness of the silicone and the fabric is substantially thinner than the thickness of the finished edge 166 shown in the undergarment 164 of FIGS. 8A and 8B. As a result, the undergarment 164′ of the present invention does not have a bulky edge that is likely to be visible through outerwear. Thus, the finished edge formed using the present invention is more stretchable and less likely to bind. FIG. 10 shows a cut pattern piece 220 having an edge 222. Although not shown in FIG. 10, the edge 222 includes a plurality of fibers having ends that terminate at the edge 222. On a microscopic scale, the free ends of the fibers at the edge are loose, which makes the edge subject to fray or tear when wearing or washing the piece 220. Referring to FIG. 11, in order to bind the free ends of the fibers, a first bead of silicone material 262 is deposited at the edge 222. The first bead of silicone material 262 preferably contacts and binds the free ends of the fibers at the edge 222 of the pattern piece 220. The pattern piece also has a series of second silicone beads 268 deposited adjacent the first silicone bead 262. The second beads 268 are preferably thinner than the first bead 262 of silicone material. The series of second beads 268 preferably extend parallel to the edge 222 of fabric 220. In other preferred embodiments, the second beads may be remote from an edge and/or may follow a path that is curved, S-shaped, or discontinuous and/or a path that comprises a series of silicone dots. FIG. 12A shows a magnified view of the pattern piece 220 shown in FIG. 11. The pattern piece 220 includes edge 222 having a first silicone bead 262 deposited over the edge for finishing the edge. Although the present invention is not limited by any particular theory of operation, it is believed that the silicone at least partially encapsulates and/or binds the free ends of the fibers to prevent the fibers from fraying and tearing. In addition, a series of second silicone beads 268 extend in a direction generally parallel with the edge 222 of fabric 220. The second silicone beads 268 are spaced apart from one another so that a face of the pattern piece 220 is exposed and/or accessible between the second beads 268. As shown in FIG. 12A, a first one 268A of the second silicone beads is spaced from the first silicone bead 262 so that first fabric section 220A is exposed therebetween. In addition, a second one 268B of the second silicone beads is spaced from the first one 268A of the second silicone beads so that a second fabric section 220B is exposed therebetween. The second silicone beads 268 continue in a similar fashion to provide a silicone web that extends a substantial distance inwardly from edge 222 of pattern piece 220. The density of the silicone web may be modified depending upon the characteristics desired for the underlying pattern piece. If the spacing between the second silicone beads of the web is increased, the pattern piece will be more stretchable and will provide less gripping. If the spacing between the second silicone beads of the web is decreased, the pattern piece will be less stretchable and provide more gripping. The spacing may be modified depending upon the intended use of the garment. FIG. 12B shows a magnified view of the pattern piece of FIG. 11. The pattern piece 220 has top surface 230 and outer edge 222. A first silicone bead 262 is deposited over the edge 222 of the pattern piece so as to finish the free ends of the fibers that terminate at the edge of the pattern piece. In addition, the web of second silicone beads 268 is deposited over the first surface 230, adjacent the first silicone bead 262. The second silicone beads 268 are preferably spaced from one another, with portions of the first surface 230 of pattern piece 220 being exposed and accessible through the web of second silicone beads 268. Although the present invention is not limited by any particular theory of operation, it is believed that providing the web of second silicone beads 268 atop the pattern piece 220 (FIGS. 12A and 12B) produces a pattern piece that is less likely to slip or ride-up over a wearer's body. Ride-up may cause an undergarment to bind around a body part, e.g. a leg, which may cause a constricted feeling. Ride-up may also cause bunching of the fabric, which may be visible through outerwear. It is believed that the web of second silicone beads provides the fabric with a gripping feature that prevents the fabric from sliding and riding-up over a wearer's body. FIG. 13 shows a process for providing a finished edge on a cut pattern piece, in accordance with certain preferred embodiments of the present invention. During a first stage 280, a spread of fabric is cut to provide one or more pattern pieces. The pattern piece may be cut by hand or using a computer-assisted cutting instrument. During a second stage 282, an edge of the cut pattern piece is aligned for applying a silicone material over the edge. A straight edge or alignment tool may be used for aligning the edge of the pattern piece. During a third stage 284, the silicone is applied to the edge in an uncured state. Due to the uncured state of the silicone, the silicone tends to at least partially encapsulate and/or bind with the free ends of the fibers at the edge of the pattern piece. The silicone may be applied along a straight edge of a pattern piece or may be applied in a pattern that follows the contour of the edge of the pattern piece, e.g. the silicone may follow the contour of a curved edge. The silicone may also be applied to an interior region of the pattern piece that is remote from an edge. The silicone may be applied along paths that are curved, S-shaped and/or non-continuous (e.g. silicone provided in a dotted pattern). During a fourth stage 286, the pattern piece may be pulled back from the alignment edge and the silicone cured during a fifth curing stage 288. During the curing stage, the silicone may be cured using air or heat. FIG. 14 shows a system for producing a finished edge on a cut pattern piece, in accordance with certain preferred embodiments of the present invention. The system 300 includes a conveyor 302 having a belt 304 that is movable over rollers 306. The belt 304 moves over the rollers 306 in the direction indicated by arrow 308. The system includes a paper storage roll 310 from which an absorbent material such as paper 312 is unwound. The absorbent paper 312 is guided into engagement with the conveyor belt 304 so that it is positioned over a top surface of the conveyor belt before a cut pattern piece is positioned on the conveyor belt. The system 300 also includes a second roll 314 that collects the absorbent paper at a point located downstream from the first roll 310. The system also includes a dispensing head 316 that applies silicone material over a cut pattern piece placed atop conveyor belt 304, and a retractor subassembly 318 that pulls the cut pattern piece off the absorbent paper 312 after the silicone material has been deposited atop the fabric. System 300 also includes a heater 320 having one or more heating coils 322 for heating the silicone applied to the fabric. During the heating process, the heat cures the silicone to permanently bind the silicone to the fabric. The system also includes one or more temperature sensors 324 provided in thermal communication with the top surface of the conveyor belt 304 so as to monitor the surface temperature of the conveyor belt. Referring to FIGS. 14 and 15A, the system 300 includes a first stage 326 where cut pattern piece 220 is placed atop absorbent paper 312, with the edge 222 of the piece 220 aligned with a guide having alignment face 330. In other preferred embodiments, the first stage 326 may have alignment fingers that mechanically align the edge of the pattern piece. After the pattern piece has been aligned, the conveyor belt 304 moves the piece 220 downstream in the direction of arrows 308 to a second stage 332 where silicone material is deposited onto the pattern piece 220. At stage 332, a dispenser 316 for silicone dispenses a first silicone bead 262 over the outer edge 222 of the pattern piece 220. Simultaneously, the dispenser 316 deposits a spaced web of second silicone beads 268 over a region of the pattern piece that is inward of the edge 222. Referring to FIGS. 14 and 15B, conveyor belt 304 continues to move the pattern piece 220 downstream to retractor stage 334. At retracting stage 334, retractor 336 moves from a retracted position 338 to an extended position 340 for engaging a section of pattern piece 220. Once the retractor 336 engages the pattern piece 220, the retractor retracts from position 340 to retracted position 338 to pull the pattern piece 220 off the absorbent paper 312. As the piece 220 is pulled of the paper 312, the first silicone bead 262 at the edge 222 is broken from its engagement with the paper 312 to provide a smooth edge of silicone at the outer edge 222 of the pattern piece 220. Once the piece has been pulled of the paper 312, the pattern piece 220 is moved downstream along conveyor 304 to a curing stage 342. At the curing stage 342, the deposited silicone material is cured using heat. Referring to FIG. 14, the curing stage has a heater 320 having heating coils 322 that produce heat. In preferred embodiments, the heating stage may include six (6) heating stations, each heating station having one or more heating elements. In one particular preferred embodiment, the heating elements are set at 600° F. so that the surface temperature of the conveyor 304 is between 260° F. and 275° F. In highly preferred embodiments, the surface temperature should be between about 268° F.-272° F. The temperature sensor 324 is interconnected with a controller 344 that may change the temperatures of the heating elements 322 depending on ambient conditions. For example, in warmer ambient temperatures, the heating elements 322 may be operated at lower temperatures than would be required under cooler ambient conditions. In certain preferred embodiments, the pattern piece and the silicone deposited on the piece are preferably cured for approximately 30 second to two minutes and more preferably about one minute. Referring to FIG. 15C, after the pattern piece 220 and the cured silicone 262, 268 exits oven 324, the pattern piece moves downstream along conveyor belt 304 to stacking station 344. At stacking station 344, the pattern piece having the cured silicone is removed from the conveyor 304 by a stacker 346 that is moveable between a first position 348 and a second position 350. In the second position 350, the stacker 346 engages pattern piece 220. The stacker 346 then moves to the first position 348. As the stacker moves between the second and first positions, the pattern piece 320 is moved in the direction D1 for being placed atop a stack 352. After a sufficient number of pattern pieces 220 have been place atop stack 352, the stack may be placed in a package for shipment to another location, i.e. an assembly facility. FIG. 16 shows a dispenser 316 for silicone, in accordance with certain preferred embodiments of the present invention. A series of openings are provided at the bottom of the dispenser 316. The openings include an elongated opening 354 adjacent the first end 356 of the dispenser and a series of smaller openings 358 that extend between elongated opening 354 and a second end 360 of the dispenser 316. In operation, high pressure is provided inside the dispenser to dispense the silicone material through the openings 354, 358. The openings 354, 358 are preferably arranged along a straight line that extends between the first end 356 and the second end 360 of the dispenser 316. FIG. 17A shows the dispenser 316 depositing silicone onto a cut pattern piece 220. The silicone is dispensed in a pattern that includes thicker first silicone bead 262 deposited at the edge of the pattern piece and a series of smaller second silicone beads 268 that are deposited inwardly from the edge. The second beads 268 are spaced from one another. As shown in FIG. 17A, the first silicone bead 262 has a width W1 that is substantially greater than the width W2 of the second silicone beads 268. In addition, the second silicone beads are spaced from one other so that gaps 270 are present between the second silicone beads. Another gap 272 is present between first silicone bead and a first one of the second silicone beads 268A. FIG. 17B shows the dispenser head 316 as the dispenser deposits silicone beads 262, 268 over a top surface 230 of pattern piece 220. The silicone is deposited as the conveyor belt 304 moves fabric 220 in a direction indicated by arrow 308. As the pattern piece 220 passes the dispensing head 316, the silicone material 262, 268 is deposited onto the top surface of the pattern piece 220. In another preferred embodiment of the present invention, a spread is made of stretchable fabric. Referring to FIG. 18, the spread 420 is more stretchable in a first axial direction designated Y than a second axial direction designated X. Pattern pieces 438 are cut from the spread 420. Referring to FIGS. 18 and 19, at least one of the cut pattern pieces 438A has a first unfinished edge 422 that extends in a third axial direct designated Z that traverses or crosses the first axial direction Y. The direction of the unfinished edge 422 can be readily modified depending upon adjustability and fit requirements. A curable polymer such as silicone is disposed over the first unfinished edge 422 for engaging free ends of fibers at the edge 422. The polymer is then cured for binding the free ends of the fibers and finishing the edge. Although the present invention is not limited by any particular theory of operation, it is believed that the stretch characteristics of fabric may be used to provide garments having more adjustability and better fit. Thus, in one embodiment, an edge may be cut that extends in a direction parallel to the direction of stretch of the fabric. In another embodiment, an edge may be cut that extends in a direction perpendicular to the direction of stretch of the fabric. In still another embodiment, an edge may be cut that extends in a direction that crosses the direction of stretch of the fabric. Thus, the direction of the cut edge may be readily modified based upon the use to which the cut pattern piece will be put. Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore contemplated that numerous modifications may be made to the illustrated embodiments and that other arrangements may be made without departing from the spirit and scope of the present invention as defined by the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>The present invention relates to manufacturing garments and particularly relates to methods for making garments having finished edges. Most garments are made by cutting fabric into pattern pieces and then sewing the cut pattern pieces together to make the garment. Typically, each cut pattern piece has one or more edges that are sewn to the edges of one or more adjacent cut pattern pieces, which forms a seam between the cut pattern pieces. The outer edges of the garment, however, are not sewn to the edges of other cut pattern pieces. As a result, the outer edges are exposed to forces that may fray or tear the fabric. In response to the tearing and fraying problem, the clothing industry has developed methods for finishing the edges of garments, including using narrow elastic, lace, trim and/or a folded over edge. The clothing industry also uses fabric having a knitted-in edge. Although this particular type of fabric provides garments having smoother edges, its use results in relatively low material yields. The most common method for finishing the edge of a cut pattern piece involves using narrow elastic. Referring to FIG. 1A , a cut pattern piece 20 is made of cotton, nylon, polyester, or spandex fibers or any other natural or synthetic fibers commonly used to make garments. As shown in FIGS. 1A and 1B , the cut pattern piece 20 has an outer edge 22 and includes a plurality of fibers 26 having free ends 28 that terminate at the edge 22 . As is well known to those skilled in the art, the free ends 28 of the fibers 26 form a rough, outer edge that tends to fray and/or tear as the fabric is used. In order to overcome the above-mentioned fraying problems in clothing such as activewear, shapewear and/or compression garments, most cut pattern pieces have a narrow elastic that is sewn onto the outer edge 22 . Referring to FIGS. 2A-2C and 3 A- 3 C, a cut pattern piece 20 has a rough, outer edge 22 with fibers having ends (not shown) that terminate at the edge. Referring to FIGS. 2A and 3A , a narrow elastic 23 is aligned over a top surface 30 of the cut pattern piece 20 . Referring to FIGS. 2B-1 , 2 B- 2 and 3 B, a flap 25 of fabric adjacent outer edge 22 is folded over the top surface 30 and the narrow elastic is positioned over the flap 25 . Referring to FIGS. 23-2 , 2 C and 3 C, the flap 25 and the narrow elastic 23 are held in place by stitching 32 for forming a finished edge 34 on the cut pattern piece. The finished edge including the flap 25 and the narrow elastic 23 has a thickness H 1 that is substantially greater than the thickness H 2 of the original cut pattern piece 20 . As a result, the finished edge is bulky and is likely to be visible through outerwear. As noted above, in most garments, the finished edge is made using a narrow elastic. In some garments, however, the finished edge is made using lace, a fold-over edge, or trim, with and without using a narrow elastic. The presence of the bulky edge ( FIG. 2C ) is not desirable, particularly when the fabric is used for producing garments such as activewear, shapewear, garments having one or more support panels and garments using compression fabric. The presence of a bulky finished edge is particularly undesirable when the fabric is to be used in undergarments and bathing suits. This is because the finished edge, as shown in FIG. 2C , adds unwanted bulkiness to the garment. For example, a bulky finished edge on an undergarment is undesirable because it may, inter alia, be seen through clothing worn over the undergarment. The bulky finished edge is also less stretchable, so that it will not readily adjust to a wearer's body. This will cause the garment to ride-up and bind to a wearer, causing discomfort. The clothing industry has also developed fabrics having knitted-in edges, whereby relatively complex stitching is used at the edges to avoid the fraying and tearing problems described above. Although garments having knitted-in edges are smoother than garments that use narrow elastic, lace and/or trim, making the fabric for the garments is more expensive. This is because a knitted-in edge requires complex knitting that adds to the cost of making the fabric. In addition, the knitted-in edge provides limitations that adversely affect material yield. Referring to FIG. 4 , a spread 20 has a knitted-in finished edge 34 formed along a lower edge thereof. The knitted-in finished edge may also have rubber fibers that are knitted into the fabric to provide gripping to increase the hold of the garment to the body. The spread 20 has a length designated L and a width designated W. In the particular example shown in FIG. 4 , the spread has a length L of 252 inches and a width W of 26 inches. A pattern is then used to define a series of pattern pieces 38 A- 38 F. An automatic cutting machine or hand-cutting tool may then be used to cut the pattern pieces 38 A- 38 F. Due to the requirement that each cut pattern piece have a portion of the knitted-in finished edge 34 incorporated therein, only one pattern piece may be cut from each of the respective panels 40 A- 40 F of spread 20 . As a result, the fabric in each panel section 40 A- 40 F that is not part of one of the cut pattern pieces 38 A- 38 F is waste material. As is well known to those skilled in the art, wasting material from a spread having a finished edge is undesirable and costly. In the particular spread 20 shown in FIG. 4 , the material yield of the spread is 57.13% because the cut pattern pieces 38 A- 38 F utilize 57.13% of the spread, with 42.87% of the spread being unusable waste material. This level of waste is undesirable in the highly competitive and cost-conscious garment industry. In view of the above-described problems, there is clearly a need for garments having finished edges that are not bulky. There is also a need for garments having finished edges that can grip and that do not ride-up over a wearer's body to cause binding. There is also a need for garments having finished edges that are smooth and that do not show through outer garments. Furthermore, there is a need for methods of making garments that improve material yield and reduce waste. | <SOH> SUMMARY OF THE INVENTION <EOH>In certain preferred embodiments of the present invention, a method of making a fabric having a finished edge includes providing a fabric having a plurality of fibers with free ends of the fibers at an edge of the fabric and disposing a curable polymer over the edge of the fabric so that the curable polymer engages the free ends of the fibers at the edge of the fabric. The method desirably includes, after the disposing step, curing the polymer for binding the free ends of the fibers at the edge of the fabric to the cured polymer. In preferred embodiments, the fabric may be made of cotton, nylon, polyester and spandex fibers or any other natural or synthetic fibers used to make fabric. In certain preferred embodiments, the fabric is cut into pattern pieces before the curable polymer material is disposed on the fabric. Each cut pattern piece may be sewn to one or more other pieces of fabric for making a garment. Although the present invention is not limited by any particular theory of operation, it is believed that cutting the pattern pieces before forming the finished edge will dramatically improve the material yield from a spread, particularly in comparison to techniques using fabric having knitted-in edges. This particular feature will be described and shown in more detail below in FIG. 5 of the present application. Prior to disposing the polymer material, an edge of the cut pattern piece is desirably positioned over an absorbent material, such as a sheet of absorbent paper. In one preferred embodiment, the absorbent paper is a roll of elongated paper that is unrolled onto a conveyor system, with the paper provided on a top surface of the conveyor, between the cut pattern piece and the conveyor. In certain preferred embodiments, at least the edge of the cut pattern piece is in contact with the absorbent material as the polymer is deposited onto the cut pattern piece. Although not limited by any particular theory of operation, it is believed that the absorbent material acts as a shield that prevents the polymer material from coming in direct contact with the conveyor. This shielding action avoids the need to clean or remove polymer from the conveyor. The absorbent material may also assist in the formation of a clean edge of cured polymer material at the edge of the pattern piece. In certain preferred embodiments, the polymer includes silicone. As is well known to those skilled in the art, a silicone is defined as any one of a large group of siloxanes that are stable over a wide range of temperatures. More specifically, silicones are any of a group of semi-inorganic polymers based on the structural unit R 2 SiO, where R is an organic group, characterized by wide-ranging thermal stability, high lubricity, extreme water repellence and physiological inertness. Silicones are typically used in lubricants, adhesives, coatings, paints, synthetic rubber, electrical insulation and prosthetic replacements for body parts. In one particularly preferred embodiment, the silicone is a compound made up of, by weight, approximately 10-30% silica and 60-90% vinylpolydimethylsiloxane. The method also desirably includes aligning the edge of the cut pattern piece with a dispenser for the curable polymer and dispensing the curable polymer from the dispenser onto the edge of the cut pattern piece. In certain preferred embodiments, the dispenser includes at least one opening for dispensing the curable polymer. In other preferred embodiments, the dispenser includes a series of openings for dispensing the curable polymer, at least one of the openings having a different size than at least another one of the openings. After the polymer has been deposited on the cut pattern piece, the polymer is desirably cured using heat. In one preferred embodiment, one or more heating stations are provided for heating the polymer material previously applied to the cut pattern piece. The cut pattern piece may be placed in thermal communication with the one or more heating elements. In one preferred embodiment, the cut pattern piece may be moved on a conveyor element, such as a conveyor belt, with the absorbent material positioned atop the conveyor and the fabric positioned at least partially on the absorbent material. Each heating station may have one or more heating elements for generating heat. The temperature of the polymer and/or the temperature of the cut pattern pieces may be monitored to insure that the polymer is heated to an adequate temperature to properly cure the polymer. In certain preferred embodiments, the polymer is heated to approximately 260-280 degrees Fahrenheit. In more preferred embodiments, the polymer is heated to approximately 265-275 degrees Fahrenheit. The time limit for heating the polymer may vary. In one preferred embodiment, heating for about one minute cures the polymer on the cut pattern piece. The conveyor element may have a top surface for supporting the cut pattern pieces. In one preferred embodiment, the conveyor element may include a conveyor belt having a top surface for supporting the cut pattern pieces as the pieces move between various stations, i.e. alignment station, disposing polymer station, curing station, etc. In one particular preferred embodiment, the top surface of the conveyor belt may include a material having a low coefficient of friction or a non-stick material such as the material sold under the trademark TEFLON. As a result, there may be no need to provide an absorbent material between the pattern pieces and the conveyor because any polymer deposited on the conveyor may be easily removed from the top surface such as by using a scrapper. The step of disposing a curable polymer on the cut pattern piece may include disposing a first polymer bead over the edge of the pattern piece and disposing at least one second polymer bead adjacent the first polymer bead. The at least one second polymer bead may be narrower than the first polymer bead. In more preferred embodiments, the at least one second polymer bead includes a plurality of second polymer beads. The at least one second polymer bead may include a plurality of second polymer beads spaced from one another, with the fabric of the pattern piece exposed between the plurality of second polymer beads. The one or more second polymer beads may extend in a direction parallel to the edge of the fabric or may extend along a path that mirrors the edge of the fabric. In other preferred embodiments, the polymer may be provided on the pattern piece away from the edge of the pattern piece. In these embodiments, the polymer may provide gripping to prevent the fabric from riding or slipping over the body of a garment wearer. The polymer may be one or more beads that follow an S-shaped or curved pattern. The one or more polymer beads may be continuous or non-continuous, e.g. intermittent deposits of polymer on a fabric. The polymer may also be provided as polymer dots on the fabric. The intermittent polymer deposits may form a matrix of polymer on a fabric. In certain preferred embodiments, the spacing between the polymer beads may be increased for increasing the stretchability of the fabric. In other preferred embodiments, the spacing between the polymer beads may be decreased for increasing the gripping of the fabric. The polymer beads may also be applied over a central region of a fabric to provide gripping at the central region for holding the fabric in place over a body. Another preferred embodiment of the present invention involves cutting a spread. As is well known to those skilled in the art, cutting a spread involves laying down fabric having a desired length in multiple layers. Typically, a spread may include 100 or more layers of fabric. Before cutting the spread into pattern pieces, a particular pattern is selected and applied to the spread. The pattern may be applied through a computer system that analyzes the length of the fabric and determines how to maximize the number of pattern pieces that may be cut from the fabric. The computer system may also control an automatic cutting machine for cutting the fabric into cut pattern pieces. The spread may also be cut by placing a pattern over the spread and cutting the pattern pieces by hand using a cutting tool. In one particular preferred embodiment, a method of making a cut pattern piece for a garment includes providing a spread, and cutting the spread to provide cut pattern pieces, each cut pattern piece including a plurality of fibers having free ends that terminate at an edge of the pattern piece. The method desirably includes after the cutting step, disposing a curable polymer over the edges of the cut pattern pieces so that the curable polymer engages the free ends of the fibers at the edges of the pattern pieces. After the curable polymer is disposed, the polymer is desirably cured for binding the free ends of the fibers at the edges of the pattern pieces to the cured polymer. Each pattern piece having the cured polymer edge may be sewn to at least one other piece of fabric for making the garment. The curable polymer material may be placed on the cut pattern piece by disposing a first polymer bead over the edge of the pattern piece and disposing at least one second polymer bead over the pattern piece adjacent the first polymer bead, whereby the at least one second polymer bead is narrower than the first polymer bead. The at least one second polymer bead may include a plurality of second polymer beads spaced from one another on the pattern piece with a face of the pattern piece being exposed between the plurality of second polymer beads. In another preferred embodiment of the present invention, a section of a garment includes a cut pattern piece having a plurality of fibers with free ends that terminate at an edge of the pattern piece, and a bead of cured polymer material provided over the edge of the pattern piece, the bead of cured polymer material encapsulating at least some of the free ends of the fibers that terminate at the edge of the pattern piece. The pattern piece desirably includes a plurality of second beads of cured polymer material disposed on the pattern piece adjacent the first bead of cured polymer material, whereby the plurality of second beads are spaced from one another on the pattern piece with a face of the pattern piece being exposed between the second beads. The second beads preferably provide gripping which holds the fabric in place over a wearer's body. The present invention provides tremendous benefits over prior art methods of making garments. Specifically, the present invention dramatically increases the material yield from fabric spreads. Prior art methods that use fabric having knitted-in edges require that the finished edge be formed on a spread before the spread is cut to make cut pattern pieces. Because the pattern pieces must be cut from the knitted-in finished edge, a large area of the spread away from the finished edge cannot be used. In contrast to these prior art methods, the present invention enables pattern pieces to be cut from any region of a spread. Thus, the cut pattern pieces do not have to incorporate a knitted-in finished edge, inter alia, because the finished edge of the present invention is preferably formed only after the pattern pieces have been cut. The present invention also enables a spread to have more layers of fabric. When laying a spread of fabric having knitted-in edges, the knitted-in edges are thicker than the rest of the fabric. This limits the number of layers that can be stacked atop one another. Typically, a spread of fabric having knitted-in edges can only be stacked 24 or 48 layers high. In addition, fabric having knitted-in edges is also harder to handle. All of these factors slow down the process of producing pattern pieces having knitted-in edges, which adds to the cost and time needed to manufacture garments. The present invention also provides finished edges that are sleeker and thinner than prior art products having a relatively thick finished edge. As described herein, a silicone bead that finishes an edge is much thinner than the prior art finished edges that use folded-over edges, narrow elastic, trim and/or lace. The silicone beads also provide a garment that grips for preventing the garment from riding over a wearer's body. As a result, the garment will not ride and bind (e.g. constrain). The present invention also provides a garment having stability due to the gripping from the polymer. This stability minimizes the likelihood that the fabric will roll over upon itself, which may result in bunching or binding of the garment. The present invention also provides a finished edge that has more stretch because it does not have a thick finished edge that is formed when using narrow elastic, trim, lace and/or a folded-over edge. In another preferred embodiment of the present invention, a garment includes a cut pattern piece made of a fabric having edges and an interior region of the fabric being spaced from the edges. The fabric may include natural fibers such as cotton fibers or synthetic fibers such as nylon, polyester and spandex fibers. The garment preferably includes at least one bead of silicone deposited in the interior region of the fabric, whereby the silicone is in contact with the fabric and provides gripping for holding the cut pattern piece in place on a wearer's body. The garment may be an undergarment, activewear, shapewear, a bathing suit, a garment having one or more support panels or a garment that uses compression fabric. In another preferred embodiment, a method of increasing material yield when cutting pattern pieces from fabric includes laying a spread of fabric having a bottom edge, cutting a plurality of pattern pieces from the spread of fabric, wherein at least some of the cut pattern pieces do not include the bottom edge of the spread of fabric, and disposing a curable polymer material such as silicone over one or more edges of the cut pattern pieces including the at least some of the cut pattern pieces that do not include the bottom edge of the spread of fabric. In this particular embodiment, the cut pattern pieces may include fibers having free ends that terminate at the one or more edges of the cut pattern pieces. The method also desirably includes curing the polymer material for finishing the one or more edges of the cut pattern pieces. In still another preferred embodiment of the present invention, a garment includes a cut pattern piece made of a fabric with fibers having free ends terminating at an edge of the cut pattern piece, and a polymer material provided on the fabric in contact with the free ends of the fibers, whereby the polymer material provides a finished edge for the cut pattern piece. The fabric may include compression fabric or stretchable fabric such as fabric used in activewear or shapewear. The garment may be an undergarment, activewear, shapewear, a bathing suit, a garment having support panels and a garment using compression fabric. In highly preferred embodiments, the finished edge of the cut pattern piece is devoid of narrow elastic, a folded-over edge, trim and/or lace. As a result, the finished edge of the present invention is not bulky and is able to more easily stretch to adjust to various body dimensions and body movements. As a result, the garment will be less likely to bind to and ride over a wearer's body. In certain preferred embodiments, the polymer material provided on the stretchable fabric includes a first polymer bead provided in contact with the free ends of the fibers and at least one second polymer bead in contact with the fabric, the at least one second polymer bead being spaced from the first polymer bead. The at least one second polymer bead desirably provides gripping for holding the fabric in place over a wearer's body. In yet another preferred embodiment of the present invention, a garment having a sleek finished edge includes a cut pattern piece made of fibers, at least some of the fibers having free ends that terminate at an edge of the cut pattern piece, and a cured polymer material such as silicone provided in contact with the free ends of the fibers at the edge of the cut pattern piece, the cured polymer material providing a sleek finished edge to the cut pattern piece, the finished edge being preferably devoid of a folded-over edge, narrow elastic, trim and/or lace. Due to the absence of the narrow elastic, trim or lace, the finished edge is much thinner than prior art finished edges, and is better suited for stretching, which prevents binding and ride-up. In still another preferred embodiment of the present invention, a method of controlling a stretchable garment utilizing the stretch characteristics of stretchable fabric includes providing a spread of stretchable fabric that is more stretchable in a first axial direction and less stretchable in a second axial direction, and cutting a pattern piece from the spread, wherein the at least one cut pattern piece has unfinished edges with free ends of fibers at the unfinished edges. The method desirably includes disposing a curable polymer over one of the unfinished edges of the cut pattern piece so that the curable polymer engages the free ends of the fibers, wherein the one of the unfinished edges having the curable polymer disposed thereon extends along a third axial direction that crosses the first axial direction, and after the disposing step, curing the polymer for finishing the edge of the fabric. The present invention provides garments that have smoother finished edges than garments that use folded-over edges, narrow elastic, trim and/or lace at the finished edge. As a result, the garments of the present invention will not have bulky finished edges. Moreover, the finished edges of the present invention are more stretchable than the finished edges of garments that use folded-over edges, narrow elastic, trim and/or lace. As a result, the finished edge of the present invention minimizes ride-up and binding. Furthermore, the smooth finished edges or the present invention are less likely to be visible through outer garments than are garments having bulky finished edges made of folded-over edges, narrow elastic, trim or lace. The present invention also improves material yield over techniques that use fabric having knitted-in edges. This is due to the fact that the finished edge is formed after the pattern piece has been cut. As a result, the cut pattern pieces of the present invention do not need to incorporate a particular edge of a spread, such as a knitted-in edge. This enables an operator to cut pattern pieces in regions of a spread that are spaced from the edges of the spread, thereby maximizing material yield. The present invention also improves material yield because an operator has more flexibility to cut a pattern piece from anywhere along a width of a spread. In contrast, methods using fabric with knitted-in edges must cut each pattern piece within the width of one of the panels of a spread. The smaller width of the panels versus an entire spread (20 inches v. 80-120 inches) reduces flexibility when marking patterns on fabric having a knitted-in edge, which further reduces material yield. Moreover, the present invention saves money because it enables the production of garments having smooth finished edges without requiring the used of fabric having costly knitted-in edges. Thus, manufacturers will save money on fabric for making garments. These and other preferred embodiments of the present invention will be described in more detail below. | 20040415 | 20070612 | 20051020 | 87385.0 | 1 | IZAGUIRRE, ISMAEL | UNDERGARMENTS HAVING FINISHED EDGES AND METHODS THEREFOR | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,826,253 | ACCEPTED | Memory device | A memory device is provided, which includes a data receive gate to buffer, in a first buffer, data to be inputted, a data transfer gate to input the data of the first buffer and buffer the same data in a second buffer, a data write gate to output the data of the second buffer to a data bus, and a memory cell to write and store the data in the data bus. In a control circuit thereof, data is not inputted to the first buffer by controlling the data receive gate and at the same time data is inputted to the second buffer by controlling the data transfer gate, depending on a time period from activation of a write enable signal to changing of a data mask signal. | 1. A memory device, comprising: a data receive gate to buffer, in a first buffer, data to be inputted, by gate control; a data transfer gate to input the data of said first buffer and buffer the same data in a second buffer by gate control; a data write gate to output the data of said second buffer to a data bus by gate control; a memory cell to write and store the data in said data bus; a selector not to connect said data bus to said memory cell when masked by a data mask signal, and to connect the data bus to the memory cell when the masking is released by the data mask signal; and a control circuit to input data to the first buffer by controlling said data receive gate according to a write enable signal and the data mask signal in a present cycle, and input the data of the first buffer to the second buffer by controlling said data transfer gate and then output the data in the second buffer to said data bus by controlling said data write gate in a subsequent cycle, wherein, in said cycle of said control circuit, data is not inputted to the first buffer by controlling the data receive gate, and at the same time data is inputted to the second buffer by controlling the data transfer gate, in a certain cycle depending on a time period from activation of the write enable signal to changing of the data mask signal. 2. The memory device according to claim 1, wherein, in said cycle of said control circuit, data is not inputted to said first buffer by said data receive gate control, while data is inputted to said second buffer by said data transfer gate, and the data in the second buffer is outputted to said data bus by said control of data write gate. 3. The memory device according to claim 1, wherein, in said cycle of said control circuit, data is not inputted to the first buffer by controlling the data receive gate, while data is inputted to the second buffer by controlling the data transfer gate, and the data in the second buffer is not outputted to the data bus by controlling the data write gate. 4. The memory device according to claim 1, wherein, in said cycle of said control circuit, said selector does not connect the data bus to the memory cell in a subsequent cycle, when data is not inputted to the first buffer by controlling the data receive gate, and inputted to the second buffer by controlling the data transfer gate. 5. The memory device according to claim 1, wherein, in said control circuit when the data in the second buffer is outputted to the data bus by controlling the data write gate, data is always inputted to the second buffer by controlling the data transfer gate within the cycle thereof and before the controlling the data write gate. 6. The memory device according to claim 5, wherein, in said control circuit, depending on a time period from activation of the write enable signal to changing of the data mask signal, in the cycle, data is inputted to the second buffer by controlling the data transfer gate, and data is not outputted to the data bus by controlling data write gate. 7. The memory device according to claim 1, further comprising: a first delay circuit to generate a first signal according to the write enable signal and the data mask signal, and output, as a first delay signal, a signal which delays, for a first delay time period, a changing point at which the first signal changes from a deactivated state to an activated state; a second delay circuit to output, as a second delay signal, a signal which delays, for a second delay time period which is longer than said first delay time period, a changing point at which the first signal changes from a deactivated state to an activated state; and wherein, in said control circuit, the data transfer gate is controlled by pulse at the changing point at which said fist delay signal changes from the deactivated state to the activated state, whereby data is inputted to the second buffer, and the data receive gate is controlled by pulse at the changing point at which the second delay signal changes from the activated state to the deactivated state, whereby data is inputted to the first buffer. 8. The memory device according to claim 7, wherein: in said first delay circuit, is generated a first signal to activate a period during which the write enable signal is activated and the data mask signal is in a mask-releasing state, and is outputted, as a fist delay signal, a signal which delays, for a first delay time period, a changing point at which the first signal changes from a deactivated state to an activated state; in said second delay circuit, is outputted, as a second delay signal, a signal which delays, for a second delay time period which is longer than said first delay time period, a changing point at which said first signal changes from a deactivated state to an activated state; and in said control circuit, data is inputted to the second buffer by controlling the data transfer gate by pulse at a changing point at which the first delay signal changes from a deactivated state to an activated state, and data is outputted to the first buffer by controlling the data receive gate by pulse at a changing point at which the second delay signal changes from an activated state to a deactivated state. 9. The memory device according to claim 1, wherein, in a cycle in which the activation period of the write enable signal is short, data is inputted to the second buffer by controlling the data transfer gate, and at the same time not inputted to the first buffer by controlling the data receive gate. 10. The memory device according to claim 1, further comprising: a mask receive gate to buffer, in a first mask buffer, a data mask signal inputted by gate control; a mask transfer gate to input a data mask signal of said first mask buffer and buffer the same signal in a second mask buffer; and a mask write gate to output to said selector the data mask signal in said second mask buffer by gate control. 11. The memory device according to claim 1, wherein said data mask signal comprises an upper byte mask signal and a lower byte mask signal. 12. The memory device according to claim 4, wherein, in said cycle of said control circuit, data is not inputted to said first buffer by controlling the data receive gate, while data is inputted to said second buffer by controlling said data transfer gate, and the data in the second buffer is outputted to the data bus by controlling said data write gate. 13. The memory device according to claim 12, wherein, in said cycle of said control circuit, data is not inputted to the first buffer by controlling the data receive gate, while data is inputted to the second buffer by controlling the data transfer gate, and the data in the second buffer is not outputted to the data bus by controlling the data write gate. 14. The memory device according to claim 13, wherein, in the control circuit, when the data in the second buffer is outputted to the data bus by controlling the data write gate, data is always inputted to the second buffer by controlling the data transfer gate in the cycle thereof and before the controlling the data write gate. 15. The memory device according to claim 14, wherein, in said control circuit, data is inputted to the second buffer by controlling the data transfer gate and at the same time is not inputted to the data bus by controlling the data write gate, depending on the time period from the activation of the write enable signal to the changing of the data mask signal in the cycle thereof. 16. The memory device according to claim 15, further comprising: a first display circuit to generate a first signal according to the write enable signal and the data mask signal, and output, as a first delay signal, a signal which delays, for a first delay time period, a changing point at which said first signal changes from a deactivated state to an activated state; and a second delay circuit to output, as a second delay signal, a signal which delays, for a second time period which is longer than the first time period, a changing point at which said first signal changes from a deactivated state to an activated state, wherein, in said control circuit, data is inputted to the second buffer by controlling the data transfer gate by pulse at an changing point at which the first delay signal changes from a deactivated state to an activated state, and data is inputted to the first buffer by controlling the data receive gate by pulse at an changing point at which the second delay signal changes from an activated state to a deactivated state. 17. The memory device according to claim 16, wherein: in said first delay circuit, is generated a first signal which activates a period during which the write enable signal is activated and the data mask signal is in mask-releasing state, and is outputted, as a first delay signal, a signal which delays, for a first delay time period, an changing point at which the first signal changes from a deactivated state to an activated state; in said second delay circuit, is outputted, as a second delay signal, a signal which delays, for a second delay time period which is longer than said first delay time period, a changing point at which said first signal changes from a deactivated state to an activated state; and in said control circuit, data is inputted to the second buffer by controlling the data transfer gate by pulse at a changing point at which the first delay signal changes from a deactivated state to an activated state, and data is inputted to the first buffer by controlling the data receive gate by pulse at a changing point at which the second delay signal changes from an activated state to a deactivated state. 18. The memory device according to claim 17, wherein, in said control circuit, data is inputted to the second buffer by controlling the data transfer gate and is not inputted to the second buffer by controlling the data receive gate, in a cycle where the activation period of the write enable signal is short. 19. The memory device according to claim 18, further comprising: a mask receive gate to buffer, in a first mask buffer, a data mask signal inputted by gate control; a mask transfer gate to input the data mask signal of said first mask buffer and buffer the same signal in a second mask buffer, by gate control; and a mask write gate to output the data mask signal in said second mask buffer to said selector by gate control. 20. The memory device according to claim 19, wherein said data mask signal comprises an upper byte mask signal and a lower byte mask signal. | CROSS-REFERENCE TO RELATED APPLICATIONS This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2003-378326, filed on Nov. 7, 2003, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a memory device and, more particularly, to a memory device to write data to a memory cell according to a write enable signal and a data mask signal. 2. Description of the Related Art There are memory devices which write data to memory cell according to a write enable signal and a data mask signal. These memory devices receive data in a buffer at a present cycle, and transfer and write the data in a subsequent cycle, according to the write enable signal and the data mask signal. In such a memory device, it is necessary to prevent erroneous writing of data due to writing malfunction. There, a delay in a write operation also has to be avoided. In a semiconductor memory device, when a write operation is externally directed in a last-second state of whether to perform writing or not, one of (1) not to perform writing, and (2) to perform writing and receive data or a masking state correctly, has to be executed. When performing the write operation, receiving of unwanted mask data which is being transferred, or writing of a prior data using another address without receiving new data, must be avoided. However, any measure to control occurrence of write commands results in a slow-down of a write operation and a write cycle. Another conventional arts are also published in the following patent documents 1 to 3. [Patent Document 1] Japanese Patent Application Laid-open No. Hei 11-7770 [Patent Document 2] Japanese Patent Application Laid-open No. 2003-7060 [Patent Document 3] Japanese Patent Application Laid-open No. 2001-351377 SUMMARY OF THE INVENTION It is an object of the present invention to provide a memory device to prevent data corruption without causing delay in write operation. According to an aspect of the present invention, is provided a memory device including: a data receive gate to buffer data inputted by gate control in a first buffer; a data transfer gate to input the data of the first buffer and buffer the data in a second buffer by gate control; a data write gate to output the data of the second buffer to a data bus by gate control; a memory cell to write and store the data on the data bus; a selector not to connect the data bus to a memory cell in the case of masking through a data mask signal, and to connect the data bus to the memory cell when the masking is released through the data mask signal; and a control circuit to, according to a write enable signal and a data mask signal, input data by controlling the data receive gate in a present cycle, and in a subsequent cycle input the data of the first buffer in the second buffer by controlling the data transfer gate and output the data of the second buffer to a data bus by controlling the data write gate. In the control circuit, data is inputted to the first buffer by controlling the data receive gate, while data is inputted to the second buffer by controlling the data transfer gate, in a certain cycle according to a time period from an activation of the write enable signal to a change in the data mask signal. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a configuration example of a semiconductor memory device (memory device) according to an embodiment of the present invention. FIG. 2 is a block diagram showing a configuration example of a byte mask input circuit, a byte mask controller, a data I/O circuit, a write data controller, and a column line selector in the FIG. 1. FIG. 3A illustrates a configuration example of the data input circuit in FIG. 2, and FIG. 3B illustrates a configuration example of the mask input circuit in FIG. 2. FIG. 4 illustrates a configuration example according to a referential example of the data input control circuit and the data input circuit in the FIG. 2. FIG. 5 is a timing chart showing operations of the circuit shown in FIG. 4. FIG. 6 illustrates a configuration example of the data input control circuit and the data input circuit in FIG. 2 according to a present embodiment. FIG. 7 is a timing chart showing operations of the circuit in FIG. 6. FIGS. 8A to 8C illustrate examples of write operations. FIG. 9 illustrates a tBS specification and a tBW specification. FIGS. 10A and 10B illustrate operational modes of the referential example in FIG. 4. FIG. 11 is a timing chart showing a write operation example. FIG. 12 illustrates an example of a data control and a mask control at an operational mode 5. FIG. 13 illustrates an example of a data control and a mask control at an operational mode 1. FIG. 14 illustrates an example of a data control and a mask control at an operational mode 2a. FIG. 15 illustrates an example of a data control and a mask control at an operational mode 2b. FIG. 16 illustrates an operational mode of the memory device according to the present embodiment in FIG. 6. FIG. 17 illustrates an example of a data control and a mask control at an operational mode 2c. FIG. 18 illustrates an example of a data control and a mask control at an operational mode 2d. FIGS. 19A to 19C are timing charts showing examples of write operations. FIG. 20 is a flowchart showing a processing example of the write operation according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing a configuration example of a semiconductor memory device (memory device) according to an embodiment of the present invention. A memory core 120 contains a word line selector 121, a sense amplifier selector 122, a memory cell 123, a sense amplifier 124 and a column line selector 125. An address ADD is supplied to an address decoder 102 through an address input circuit 101. The address decoder 102 performs decoding based on the address ADD, and outputs a control signal to the selectors 121, 122, and 125. A self refresh timer 103 outputs a refresh command refpz to an arbiter 104. A chip enable signal /CE1, an output enable signal /OE, and a write enable signal /WE are supplied to a command controller 106 through a command input circuit 105. An upper byte mask signal /UB enables an upper byte by releasing masking, and disables an upper byte by masking. A lower byte mask signal /LB enables a lower byte by releasing masking, and disables a lower byte by masking. The command controller 106 outputs a read command rdpz or a write command wrpz to the arbiter 104 based on the signals /CE1, /OE, /WE, /UB, and /LB. The read command rdpz is a command to read data from the memory cell 123. The write command wrpz is a command to write data to the memory cell 123. The refresh command refpz is a command to refresh the memory cell 123. The refreshing is an operation to supply electric charge in order for a memory of a DRAM not to be lost. The DRAM, which is one form of the semiconductor memory device, has a condenser in the memory cell 123 thereof, and keeps its data by storing electric charge in the condenser. The electric charge thereof decreases as time passes, and after a certain time, data are lost with a complete discharge, if being left. To prevent the discharge, the DRAM needs to perform a refresh operation in which charge injection is carried out at certain intervals. During the refresh operation, neither reading nor writing can be performed. On the other hand, refreshing cannot be carried out during reading or writing. Hence, upon occurrence of the read command rdpz or the write command wrpz during the refreshing, the read or the write operation is kept on standby. On the other hand, when the refresh command refpz occurs during the reading or the writing, the refresh operation is kept on standby. The arbiter 104 outputs the refresh command refpz, the read command rdpz, and the write command wrpz to a timing controller 107 in chronological order. The timing controller 107 outputs control signals mwlonz, msaez, and so forth to the word line selector, the sense amplifier selector 122, and the column line selector 125, according to the refresh command refpz, the read command rdpz, and the write command wrpz. The control signal mwlonz is supplied to the word line selector 121, and the control signal msaez is supplied to the sense amplifier selector 122. The upper byte mask signal /UB and the lower byte mask signal /LB are supplied to a byte mask controller 109 through a byte mask input circuit 108. Based on the signals, the byte mask controller 109 outputs a control signal to the column line selector 125. The memory cell 123 in a two-dimensional array is specified by a word line and by a column line. The word line selector 121 selects and activates the word line according to the control signal. The column line selector 125 selects the column line according the control signal. When a write command wrpz occurs, data can be written to and stored in the specified memory cell 123. When a read command rdpz occurs, data can be read out from the specified memory cell 123. Data access to and from the memory cell 123 is carried out according to the read command rdpz and the write command wrpz. The sense amplifier selector 122 activates the sense amplifier 124 according to a control signal. The sense amplifier 124 amplifies a signal (data) on a bit line of the memory cell 123. When the read command rdpz occurs, a read data controller 112 reads data from the memory cell 123 through the column line selector 125, and outputs a data DQ externally through a data I/O circuit 110. When the write command wrpz occurs, a write data controller 111 inputs the data DQ through the data I/O circuit 110 and write the data to the memory cell 123 through the column line selector 125. FIG. 2 is a configuration example of the byte mask input circuit 108, the byte mask controller 109, the data I/O circuit 110, the write data controller 111, and the column line selector 125. A command generator 201 outputs a write command signal wrpx based on the write enable signal /WE. The write command signal wrpx is a pulse signal generated at a time when the falling of the write enable signal /WE is delayed. A timing delay circuit 204 outputs a write command signal bwrpz adjusting timing by delaying the write command signal wrpx. A mask input control circuit 202 generates a signal dmlpz based on the data byte mask signals /UB and /LB. A mask input circuit 205 outputs signals dmx(/UB) and dmx(/LB) based on the signals /LB, /UB, dmlpz, wrpx, and bwrpz. Details of the mask input circuit 205 will be described later with reference to FIG. 3B. A column line control circuit 206 outputs signals clz(/UB) and clz(/LB) based on the signals dmx(/UB) and dmz(/LB). The data input control circuit 203 outputs upper byte signals wdlupz and pwdlupz, and lower byte signals wdllpz and pwdllpz, based on the write enable signal /WE and the data byte mask signals /UB and /LB. An upper byte data input circuit 207U inputs upper byte data DQ(/UB) and outputs upper byte data cdbz(/UB) according to signals /UB, pwdluzp, wdlupz, wdllpz, and bwrpz. A lower byte data input circuit 207L inputs lower byte data DQ(/LB) and outputs lower byte data cdbz(/LB) according to signals /LB, pwdllzp, wdlupz, wdllpz, and bwrpz. Details of the data input circuits 207U and 207L will be described later with reference to FIG. 3A. To an upper byte column line selecting circuit 208U, the data cdbz(/UB) is inputted, and from the same circuit, bit line signals b1(/UB) and /b1(/UB) are outputted, according to the signal clz(/UB). To a lower byte column line selecting circuit 208L, the data cdbz(/LB) is inputted, and from the same circuit, bit line signals b1(/LB) and /b1(/LB) are outputted, according to the signal clz. More specifically, the column line selecting circuits 208U and 208L selectively connects the data bus (signal cdbz) and the bit lines of the memory cell 124 (signals b1, /b1). FIG. 3A shows a configuration example of the data input circuits 207U and 207L in FIG. 2. First, the configuration example of the upper byte data input circuit 207U is explained. A data receive gate 301U buffers, in a buffer 302U, upper byte data DQ(/UB) to be inputted, based on gate control by the signal pwdlupz. A data transfer gate 303U inputs the data in the buffer 302U and buffers the same data in a buffer 304U, based on gate control by a logical add signal of the signals wdlupz or wdllpz. A data write gate 305U outputs the data in the buffer 304U to a data bus as signal cdbz(/UB), based on gate control by the signal bwrpz. Next, the configuration example of the lower byte data input circuit 207L is explained. A data receive gate 301L buffers, in a buffer 302L, lower byte data DQ(/LB) to be inputted, based on gate control by the signal pwdllpz. A data transfer gate 303L inputs the data of the buffer 302L and buffers the same data in a buffer 304L, based on gate control by a logical add signal of the signal wdlupz or wdllpz. A data write gate 305L outputs the data in the buffer 304L to a data bus as a signal cdbz (/LB) based on gate control by the signal bwrpz. Hereinafter, the data receive gates 301U and 301L are collectively called a data receive gate GD1, the data transfer gates 303U and 303L are collectively called a data transfer gate GD2, and the data write gates 305U and 305L are collectively called a data write gate GD3. FIG. 3B shows a configuration example of the mask input circuit 205 in FIG. 2. First, the circuit of the upper byte mask signal /UB is explained. A mask receive gate 311U buffers, in a buffer 312U, the upper byte mask signal /UB to be inputted, based on gate control by the signal dmlpz. A mask transfer gate 313U inputs the mask signal of the buffer 312U and buffer the same signal in a buffer 314U, based on gate control by the signal bwrpz. A mask write gate 315U outputs the mask signal in the buffer 314U as signal dmx(/UB) based on gate control by the signal wrpx. Next, the circuit of the lower byte mask signal /LB is explained. A mask receive gate 311L buffers, in a buffer 312L, the lower byte mask signal /LB to be inputted, based on gate control by the signal dmlpz. A mask transfer gate 313L inputs the mask signal of the buffer 312L and buffers the same signal in a buffer 314L, based on gate control by the signal bwrpz. A mask write gate 315L outputs the mask signal in the buffer 314L as signal dmx(/LB) based on gate control by the signal wrpx. Hereinafter, the mask receive gates 331U and 311L are collectively called a mask receive gate GM1, the mask transfer gates 313U and 313L are collectively called a mask transfer gate GM2, and the mask write gates 315U and 315L are collectively called a mask write gate GM3. FIG. 4 is a configuration example according to a referential example of the data input control circuit 203 and the data input circuit 207U in FIG. 2. While FIG. 4 illustrates the configuration of the circuit of the upper byte, the configuration of the lower byte circuit is in the same manner as in the upper byte circuit. FIG. 5 is a timing chart to show operations of the circuit in FIG. 4. In FIG. 5, the write cycle C1 or C2 is determined according to the switching of the address ADD (FIG. 1). The first cycle C1 is a cycle for a first write operation WR1, and the second cycle C2 is a cycle for a second write operation WR2. A CDINBUF circuit 401 outputs a data DQ1 by buffering a data DQ(/UB). To a CDINLAT circuit 402, the data DQ1 is inputted, and from the same circuit, a data DQ2 is outputted by adjusting the setup/hold timing, according to control by the signal wdluz. To a CWDLGEN(/UB) circuit 403, a write enable signal /WE, a chip enable signal /CE1, and an upper byte mask signal /UB are inputted, and from the same circuit, a signal wdluz is outputted. Specifically, the CWDLGEN(/UB) circuit 403 generates a first signal (the signal wdluz shown in dotted line) to activate a period during which the chip enable signal /CE1 and the write enable signal /WE are activated (low level) and at the same time the upper level mask signal /UB indicates a mask release (low level), and outputs, as a first delay signal wdluz, a signal which delays a changing point at which the first signal changes from a deactivated state (high level) to an activated state (low level). To a CWDLPGEN (/UB) circuit 404, the signal wdluz is inputted, and from the same circuit, the signals pwdlupz and wdlupz are outputted. The signal wdlupz is a data transfer gate pulse signal to generate a pulse at a changing point at which the signal wdluz changes from high level into low level. The signal pwdlupz is a data receive gate pulse signal to generate a pulse at a changing point at which the signal wdluz changes from low level to high level. To a CWDBSW circuit 405, which corresponds to the circuit shown in FIG. 3A, the data DQ2 is inputted, and from the same circuit, a data cdpz is outputted based on control by signals bwrpz, pwdlupz, wdlupz, and wdllpz. The signal bwrpz generates a pulse at a point up to which the falling of the write enable signal /WE is delayed. As shown in FIG. 3A, the data receive gate GD1 inputs the data DQ2 to the buffer 302U according to gate control by the signal pwdlupz. The data transfer gate GD2 inputs data to the buffer 304U according to a logical add signal of the signals wdlupz and wdllpz. The data write gate GD3 outputs the data in the buffer 304U to the data bus according to control by the signal bwrpz. As described above, a high/low level judgment of the inputted data DQ (/UB) is carried out in the CDINBUF circuit 401, the setup/hold timing adjustment is carried out in the CDINLAT circuit 402, and data is transferred to the data bus in the CWDBSW circuit 405. In the CWDBSW circuit 405, the upper byte data DQ2 is received in the buffer 302U with the signal pwdlupz, and the data is transferred to the buffer 304U with the signal wdlupz or the signal wdllpz. The timing for data transfer to the data bus is adjusted by carrying out such transfer according to the signal bwrpz which is generated when writing of the data is performed. Such control of receiving and transferring data is performed in the CWDLGEN circuit 403 and the CWDLPGEN circuit 404, providing the filtering to judge whether to perform a write operation or to wait without performing the writing in the CWDLGEN circuit 403, in which the data transfer pulse signal wdlupz and the data receive pulse signal pwdlupz are generated from the respective edges of the falling and the rising of the output signal wdluz. Hence, a highly precise adjustment of the boundary of performing or not performing the write operation and the presence of data receive and data transfer is necessary, since the avoidance of a data receive in the case of non-performing of a write operation which causes data corruption results in non-performing of data transfer. Under normal circumstances, the byte mask signals /UB and /LB should be changed and determined before the falling of the write enable signal /WE. However, as shown in FIG. 5, in some cases the changes of byte mask signals /UB and /LB occur later than the falling of the write enable signal /WE, because of variations and fluctuations of the power supply voltage or the elements. In such cases, the control not to bring a malfunction is necessary. In normal circumstances, the falling of the write enable signal /WE and the changing point of the byte mask signals /UB and /LB coincide. In that case, in the cycle C1 for example, data is received in the buffer 302U with the data receive gate signal pwdlupz. In the subsequent cycle C2, the data is transferred to the buffer 304U with the data transfer signal wdlupz or wdllpz, and at the same time, the data is outputted to the data bus to be written to the memory cell with the subsequent data write signal bwrpz. These steps form the write cycle. In the case where the switching of the byte mask signals /UB and /LB occur later than the falling of the write enable signal /WE, a write state to a byte which should have been masked at an early write stage (a lower byte, for example) occurs in the circuit. As a result, despite that a data at the point of the rising of the lower byte mask signal /LB should not be received at the write operation WR1, the lower byte data DQ (/LB) is received with a pulse 501 of the data receive gate signal pwdllpz in the present cycle C1, and the data is transferred with a pulse 502 of the data transfer gate signal wdllpz, and then outputted to the data bus with a pulse 503 of the data write gate signal bwrpz in the subsequent cycle C2. The data is corrupted since it is written to the memory cell by the write operation performed after the occurrence of the pulse 503. That is to say, since the lower byte data DQ (/LB) is not supplied at the point of the occurrence of the pulse 501, the data received with the pulse 501 is an undefined (improper) data. By writing such data to the memory cell, the data corruption occurs. The above-described problem can be solved by the present embodiment described below. FIG. 6 shows a configuration example of the data input control circuit 203 and the data input circuit 207U in the FIG. 2 according to the present embodiment. Whilst FIG. 6 shows the configuration of an upper byte circuit, the configuration of a lower byte circuit is in the same manner as that of the upper byte circuit. FIG. 7 is a timing chart to show operations of the circuit in FIG. 6. In FIG. 7, a first cycle C1 and a second cycle C2 are carried out depending on the switching of the address ADD (FIG. 1). The first cycle C1 is a cycle for a first write operation WR1, and the second cycle C2 is a cycle for a second write operation WR2. The points of differences in the circuit of FIG. 6 compared with the circuit of FIG. 4 are a CWDLGEN (/UB) circuit 603 and a CWDLPGEN (/UB) circuit 604 being provided in place of the CWDLGEN (/UB) circuit 403 and the CWDLPGEN (/UB) circuit 404 respectively. To the CWDLGEN (/UB) circuit 603, a write enable signal /WE, a chip enable signal /CE1, and an upper byte mask signal /UB are inputted, and from the same circuit, signals wdluz and pwdluz are outputted. More specifically, the CWDLGEN (/UB) circuit 603 generates a first signal (signal wdluz shown in dotted line) to activate (bring to low level) a time period during which the chip enable signal /CE1 and the write enable signal /WE are activated (low level) and at the same time the upper byte mask signal /UB are indicating a mask release (low level), and outputs, as a first delay signal wdluz, the signal which delays the changing point at which the first signal changes from the deactivated state (high level) into the activated state (low level) for a first delay time period. Further, the CWDLGEN (/UB) circuit 603 outputs, as a second delay signal pwdluz, the signal which delays the changing point at which the above-described first signal (signal pwdluz shown in dotted line) changes from the deactivated state (high level) into the activated state (low level) for a second delay time period which is longer the first delay time period. To a CWDLPGEN (/UB) circuit 604, the signals wdluz and pwdluz are inputted, and from the same circuit, signals pwdlupz and wdlupz are outputted. The signal wdlupz is a data transfer gate pulse signal to generate a pulse at a changing point at which the signal wdluz changes from high level to low level. The signal pwdlupz is a data receive gate pulse signal to generate pulse at a changing point at which the signal pwdluz changes from low level to high level. In the present embodiment, filters for the CWDLGEN circuit 603 are separately prepared for the data receive signal and the data transfer signal. This allows a state in which data transfer (with the signal wdllpz) is performed while data receive (with the signal pwdllpz) is not performed. As a result, a data corruption caused by a subsequent data passing through to the data bus as shown in FIGS. 4 and 5 can be prevented. This feature will be explained later in detail with reference to FIGS. 8A to 8C. In FIG. 7, the lower byte mask signal is at high level (in masked state) in a cycle C1, and the lower byte data DQ (/LB) is not supplied. The lower byte data receive pulse 701 does not occur, so that it is prevented to receive and write undefined (improper) data in the memory cell. Specifically, in a subsequent cycle C2, a data transfer pulse 702 and a data write pulse 703 occur, and a preceding data is supplied to the data bus. However, since the lower byte mask signal /LB is supplied to the column line selecting circuit 208L (FIG. 2) as high level, the data bus is not connected to the memory cell. As a result, writing to the memory cell is not performed, so that the data corruption does not occur. Subsequently, the lower byte receive gate signal pwdllpz generates a pulse in the cycle C2, and the lower byte data DQ (/LB) is received. Further in the following cycle, the data is transferred with the data transfer gate signal, and supplied to the data bus with the data write gate signal. The lower byte mask signal /LB is then supplied to the column line selecting circuit 208L (FIG. 2) as low level, and the data bus is connected to the memory cell. Consequently, a proper data is written to the memory cell. As described above, in the cycle C2, when the lower byte data is transferred and the high level of the mask signal is received, the data bus is not connected to the memory cell so that the data corruption does not occur, since the data is not actually written to the memory cell. Accordingly, any loosening of the control to the occurrence of the write command itself does not cause data corruption, and a slow-down of the write cycle operations can be prevented. Hence, by providing a proper order of precedence for mask receive, data receive, data write, and data transfer, the data corruption does not occur when a write command occurs, so that the delay in the write operation can be prevented. FIGS. 8A to 8C show examples of the write operations. In the examples, write operations WR0, WR1, and WR2 are sequentially performed for each cycle. FIG. 8A shows an example of a basic write operation. It shows a normal operation in which the low-level period of the write operations WR1 and WR2 is sufficiently long in a write enable signal /WE. When the write enable signal /WE falls to perform the write operation WR1, data transfer GD2[0] of the write operation WR0 is performed, and mask receive GM1[1] of the write operation WR1 is performed. This is followed by mask write GM3[0] of the write operation WR0. Subsequently, data write GD3[0] of the write operation WR0 is performed, and mask transfer GM2[1] of the write operation WR1 is performed. Thereafter, the data is written to the memory cell with a write command WR[0] of the write operation WR0. Further, when the write enable signal /WE rises, data receive GD1[1] of the write operation WR1 is performed. Next, when the write enable signal /WE falls to perform the write operation WR2, data transfer GD2[1] of the write operation WR1 is performed, and mask receive GM1[2] of the write operation WR2 is performed. Subsequently, mask write GM3[1] of the write operation WR1 is performed. This is followed by data write GD3[1] of the write operation WR1, and then mask transfer GM2[2] of the write operation WR2. Thereafter, the data is written to the memory cell with a write command WR[1] of the write operation WR1. Further, when the write enable signal /WE rises, data receive GD1[2] of the write operation WR2 is performed. FIG. 8B shows a write operation example of the referential example of the memory device in FIG. 4. The example shows a malfunction in the case where the low-level period of the write operation WR1 is short in the write enable signal /WE. When the write enable signal /WE falls to perform the write operation WR1, data transfer GD2[0] of the write operation WR0 is performed, and overlappingly, data receive GD1[1] of the write operation WR1 is performed. This causes a simultaneous opening of the data transfer gate GD2 and data receive gate GD1 in FIG. 3A, because of a partial overlap of the pulse of the data transfer gate signal wdlupz and the pulse of the data receive gate signal pwdlupz. Consequently, instead of the data of the write operation WR0 which should have been stored, the data of the write operation WR1 is erroneously stored in the buffer 304U. In the subsequent data write GD3[0] and the write command WR [0], the data of the write operation WR1 is written to the memory cell, which is a malfunction. This occurs because the data transfer gate signal wdlupz and the data receive gate signal pwdlupz are generated based on the falling and the rising of the same signal wdluz, as shown in FIG. 5. That is to say, when the pulse of the data transfer gate signal wdlupz is generated, the pulse of the data receive gate signal pwdlupz is always generated, causing an overlap of the pulses of the both signals if the low-level period of the write enable signal /WE is short. FIG. 8C shows a write operation example of the memory device of the present embodiment in FIG. 6. This example shows that a malfunction can be prevented where the low-level period of the write operation WR1 is short in the write enable signal /WE. When the write enable signal /WE falls to perform the write operation WR1, data transfer GD2[0] of the write operation WR0 is performed. However, since the low-level period of the write enable signal /WE is short, data receive GD1[1] of the write operation WR1 is not performed. That is to say, in FIG. 7, when the low-level period of the write enable signal /WE is short, the low-level period occurs in the signal wdluz whose delay time is short, while the low-level period does not occur in the signal pwdluz whose delay time is long. Consequently, a pulse of the data transfer gate signal wdlupz is generated and the data transfer GD[0] is performed, while a pulse of the data receive gate signal pwdlupz is not generated and the data receive GD1[1] is not performed. This results in opening of the data transfer gate GD2 and closing of the data receive gate GD1, whereby a proper data of the write operation WR0 is stored in the buffer 304U, and the data is written to the memory cell with the data write GD3[0] and the write command WR[0], so that a normal operation is secured. FIG. 9 is for explaining a tBS specification and a tBW specification. As described above, if the byte mask signals /UB and /LB are changed and fixed when or before the write enable signal /WE falls, a normal write operation can be performed. If the byte mask signals/UB and /LB change after the falling of the write enable signal /WE, a measure has to be taken to prevent a malfunction. Here, a time tBS[0] indicates a negative time period from the activation (low level) of the write enable signal /WE to the changing of the byte mask signals /UB and /LB. A time tBW[1] is a time period from the changing of the byte mask signals /UB and /LB to the deactivation (high level) of the write enable signal /WE. FIGS. 10A and 10B show operational modes of the memory device of the referential example in FIG. 4. Data transfer GD2 and data receive GD1 are both carried out, or otherwise, neither of them are carried out. The horizontal axis shows a time tBS[ns], and the left part to the 0 (zero) line shows negative values. FIG. 10A shows a case in which data write GD3 is prioritized over the data transfer GD2 and the data receive GD1. The time tBS (negative value) becomes shorter in the order of operational modes 1, 2a, 3a, 4, and 5. In the operational mode 1 of a cycle, the data write GD3, data transfer GD2 and data receive GD1 are not performed, and mask receive GM1 receives the high level as a mask signal /UB. Accordingly, writing to a memory cell is not performed, and malfunction (data corruption) does not occur. In the operational mode 2a of the cycle, the data write GD3 is performed while the data transfer GD2 and the data receive GD1 are not performed, and the mask receive GM1 receives the high level as the mask signal /UB. Here, since the data write GD3 is performed while the data transfer GD2 is not performed, a proper data is not written to the memory cell, whereby in some cases data corruption occurs. In the cycle of the operational mode 3a, the data write GD3, the data transfer GD2, and the data receive GD1 are performed, and the mask receive GM1 receives the high level as the mask signal /UB. Here, as shown in FIG. 8B, the data transfer GD2 and the data receive GD1 may overlap timewise, so that an improper data is written to the memory cell and data corruption occurs. In the operational mode 4 of the cycle, the data write GD3, the data transfer GD2, and the data receive GD1 are performed, and the mask receive GM1 receives an undefined value as the mask signal /UB. Because the undefined value is received as the mask signal /UB, an appropriate mask control (column line selection) is not secured, whereby data corruption may occur. Since the operational mode 4 is the boundary of the high level (operational modes 1 to 3a) and the low level (operational mode 5) of the mask signal /UB, the mask signal /UB becomes an undefined value. In the operational mode 5 of the cycle, the data write GD 3, data transfer GD 2, and data receive GD1 are performed, and the mask receive GM1 receives the low level as the mask signal /UB. Here, a normal write operation is performed. FIG. 10B shows a case where the data transfer GD2 and the data receive GD1 are prioritized over the data write GD3. The time tBS (negative value) is shorter in the order of the operational modes 1, 2b, 3b, 4, and 5. The operational mode 1, 4, and 5 are identical to those in FIG. 10A. The operational mode 3b in FIG. 10B may result in data corruption which is similar to that of the operational mode 3a in FIG. 10A. In the operational mode 2b of a cycle, the data write GD3 is not performed, the data transfer GD2 and the data receive GD1 are performed, and the mask receive GM1 receives the high level as the mask signal /UB. Here, since the data receive GD1 and the data transfer GD2 are performed while the data write GD3 is not performed, the data is overwritten in the buffer 304U, whereby in some cases data corruption occurs. FIG. 11 shows a write operation example for explaining FIGS. 12 to 15, and FIGS. 17 and 18. The low-level period of the write enable signal /WE occurs in the order of the write operations WR1, WR2, and WR3. In such periods, the mask signal /LB indicates high level. In the write operation WR1, M1 is supplied as the mask signal /UB, and D1 is supplied as the data DQ. In the write operation WR2, M2 is supplied as the mask signal /UB, and D2 is supplied as the data DQ. In the write operation WR3, M3 is supplied as the mask signal /UB, and D3 is supplied as the data DQ. FIG. 12 shows data control and mask control examples of the operational mode 5. A case is shown in which the low-level period of the write enable signal /WE (write operations WR1 to WR3) is sufficiently long. When the write operation WR1 is directed with the falling of the write enable signal /WE, the switch of the data transfer gate GD2 is closed, and data DO (zero) is stored in the buffer 304U, while the switch of the mask receive gate GM1 is closed and the mask signal M1 is stored in the buffer 312U. The switch of the data write gate GD3 is then closed, and the data D0 (zero) is outputted to the data bus, while the switch of the mask write gate GM 3 is closed and the mask signal M0 (zero) is outputted. The switch of the mask transfer gate GM2 is subsequently closed and the mask signal M1 is stored in the buffer 314U. The switch of the data receive gate GD1 is then closed, and the data D1 is stored in the buffer 302U. The write operation WR0 (zero) (data D0 (zero)) is carried out in a normal manner. When the write operation WR2 is directed with the falling of the write enable signal /WE, the switch of the data transfer gate GD2 is closed and the data D1 is stored in the buffer 304U. The switch of the mask receive gate GM1 is closed and the mask signal M2 is stored in the buffer 312U. The switch of the data write gate GD3 is then closed and the data D1 is outputted to the data bus. The switch of the mask write gate GM3 is closed and the mask signal M1 is outputted. The switch of the mask transfer gate GM2 is then closed, and the mask signal M2 is stored in the buffer 314U. The switch of the data receive gate GD1 is then closed, and the data D2 is stored in the buffer 302U. The write operation WR1 (data D1) is carried out in a normal manner. When the write operation WR3 is directed with the falling of the write enable signal /WE, the switch of the data transfer gate GD2 is closed and the data D2 is stored in the buffer 304U, while the switch of the mask receive gate GM1 is closed and the mask signal M3 is stored in the buffer 312U. The switch of the data write gate GD3 is then closed and the data D2 is outputted to the data bus, while the switch of the mask write gate GM3 is closed and the mask signal M2 is outputted. The switch of the mask transfer gate GM2 is subsequently closed and the mask signal M3 is stored in the buffer 314U. The switch of the data receive gate GD1 is then closed and the data D3 is stored in the buffer 302U. The write operation WR2 (data D2) is carried out in a normal manner. FIG. 13 is data control and mask control examples of the operational mode 1. It is basically the same as examples in FIG. 12, except for those described below. A case is shown in which the low-level period of the write enable signal /WE (write operation WR2) is short. When the write operation WR2 is directed with the falling of the write enable signal /WE, the switch of the data transfer gate GD2 is kept open, while the switch of the mask receive gate GM1 is closed and the mask signal M2 is stored in the buffer 312U. Subsequently, the switch of the data write gate GD3 is kept open, and the switch of the mask write gate GM3 is kept open. Further, the switch of the mask transfer gate GM2 is kept open. Subsequently, the switch of the data receive gate GD1 is kept open. The write operation WR1 (data D1) is not carried out in this cycle, and is carried out in the subsequent cycle. FIG. 14 shows examples of data control and mask control by the operational mode 2a. It is essentially the same as FIG. 12, except for the points which will be explained below. These describe the cases where the low level period of the write enable signal /WE (write operation WR2) is around an intermediate value. When the write operation WR2 is directed with the falling of the write enable signal /WE, the switch of the mask receive gate GM1 closes while the switch of the data transfer gate GD2 is kept open, and the mask signal M2 is stored in the buffer 312U. The switch of the data write gate GD3 then closes, whereby a data D0 (zero) is outputted to the data bus, while the switch of the mask write gate GM3 closes, whereby the mask signal M1 is outputted. Subsequently, the switch of the mask transfer gate GM2 closes and the mask signal M2 is stored in the buffer 314U. Thereafter, the switch of the data receive gate GD1 is kept open. In the above-described cycle, an improper data D0 (zero) is written with the mask signal M1, resulting in data corruption. In a subsequent cycle, the mask signal is high level, and the data bus of the data D1 is not connected to the memory cell, so that writing to the memory cell is not performed. As a result, the write operation of the data D1 is not carried out, and the data is corrupted. FIG. 15 shows an example of data control and mask control in the operational mode 2b. It is essentially the same as FIG. 12, except for the points which will be explained below. These describe the cases where the low level period of the write enable signal /WE (write operation WR2) is around an intermediate value. When the write operation WR2 is directed with the falling of the write enable signal /WE, the switch of the data transfer gate GD2 closes and the data D1 is stored in the buffer 304U, while the switch of the mask receive gate GM1 is closed and the mask signal M2 is stored in the buffer 312U. Subsequently, the switch of the data write gate GD3 is kept open, and the switch of the mask write gate GM3 is kept open. Next, the switch of the mask transfer gate GM2 is kept open. Thereafter, the switch of the data receive gate GD1 closes and the data D2 is stored in the buffer 302U. In this cycle, the data D0 (zero) is updated while the switch of the data write gate GD3 is kept open, and no new data writing is performed. In a subsequent cycle, the data D2 is written to the memory cell. This means that the write operation WR1 (data D1) is skipped, so that data corruption occurs. As described above, in FIG. 10A, the data transfer GD2 is not performed in the state of the operational mode 2a commenced by the data write GD3, so that the data is corrupted. In the region of the operational mode 3a, the data receive pulse and the data transfer pulse simultaneously occur in the boundary of the operational modes 2a and 3a, so that the data passes through in the subsequent cycle, resulting in corruption of the data in the buffer 304U. In the operational mode 4, instability of the mask receive GM1 prohibits the intended write operation. In the operational mode 5, the mask receive GM1, data receive GD1, and the data transfer GD2 are normally performed, allowing the intended write operation to be carried out. FIG. 16 shows an operational mode of the memory device of the present embodiment in FIG. 6. The occurring priority is higher in the order of the data receive GD1, the data write GD3, and the data transfer GD2. The horizontal axis shows the time tBS[ns], and values for the left side of the 0 (zero) line are negative. The time tBS (negative value) is smaller in the order of the operational modes 1, 2c, 2d, 3, 4, and 5. The operational modes 1, 3, 4, and 5 are identical to those for FIG. 10A. In the operational mode 2c, of a cycle, the data transfer GD2 is performed while the data write GD3 and the data receive GD1 are not performed, and the mask receive GM1 receives the high level as the mask signal /UB. Details thereof will be explained later with reference to FIG. 17. In the operational mode 2d of the cycle, the data write GD3 and the data transfer GD2 are performed while the data receive GD1 is not performed, and the mask receive GM1 receives the high level as the mask signal /UB. Details thereof will be explained later with reference to FIG. 18. In the operational mode 3, the data corruption does not occur by an overlap of the data transfer GD2[0] and the data receive GD1[1] as shown in FIG. 8B. In such a case, as shown in FIG. 8C, the data receive GD1[1] does not occur, which means the operational mode is 2d. In the operational mode 3, the data transfer GD2[0] and the data receive GD1[1] are performed without overlapping, so that data corruption does not occur. FIG. 17 shows examples of data control and mask control of the operational mode 2c. It is essentially the same as FIG. 12, except for the points which will be explained below. These describe the cases where the low level period of the write enable signal /WE (write operation WR2) is around an intermediate value. When the write operation WR2 is directed with the falling of the write enable signal /WE, the switch of the data transfer gate GD2 is closed and the mask signal M2 is stored in the buffer 312U. Subsequently, the switch of the data write gate GD3 is kept open, and the switch of the mask write gate GM3 is kept open. Next, the switch of the mask transfer gate GM2 is kept open. Subsequently, the switch of the data receive gate GD1 is kept open. The write operation WR1 (data D1) is not performed in this cycle, and is performed in the subsequent cycle. FIG. 18 shows examples of data control and mask control of the operational mode 2d. It is essentially the same as FIG. 12, except for the points which will be explained below. These describe the cases where the low level period of the write enable signal /WE (write operation WR2) is around an intermediate value. When the write operation WR2 is directed with the falling of the write enable signal /WE, the switch of the data transfer gate GD2 is closed, whereby the data D1 is stored in the buffer 304U, and the switch of the mask receive gate GM1 is closed, whereby the mask signal M2 is stored in the buffer 312U. Subsequently, the switch of the data write gate GD3 is closed, whereby the data D1 is outputted to the data bus, and the switch of the mask write gate GM3 is closed, whereby the signal M1 is outputted. Next, the switch of the mask transfer gate GM2 is closed and the mask signal M2 is stored in the buffer 314U. Subsequently, the switch of the data receive gate GD1 is kept open. In this cycle, the write operation WR1 (data D1) is normally carried out. In the subsequent cycle, the mask signal becomes high level, and the data bus and the memory cell are not connected, so that the data D1 is not written to the memory cell. Consequently, the writing of the data D0 (zero) and D1 are normally carried out. As described above, in the present embodiment, neither the data write GD3 nor the data transfer GD2 are performed in the operational mode 1. In the operational mode 2c, the data write GD3 is not carried out, while the data transfer GD2 is performed in preparation for the subsequent write operation. In the operational mode 2d, the mask signal is high level and the write command is recognized, but an actual writing is not carried out. At that time, the data at risetime of the byte mask signal is not received. In the operational mode 3, the mask signal is high level and the write command is recognized, but an actual writing is not carried out. At that time, the data at risetime of the byte mask signal is received. In the operational mode 4, the write operation is performed because of the erroneous receiving of the mask signal of an undefined value, which causes data corruption. In the operational mode 5, the write operation is performed by receiving the data corresponding to the low level of the byte mask signal. It is in the operational mode 4 that the data corruption occurs, where the timing for the mask receive GM1 fluctuates because of the timing fluctuation by the fluctuation of the power supply voltage or the like. Hence, the operations become unstable in which “write” (WR) or “no write” (No WR) occurs depending on the conditions. In the case of “no write” (No WR), actual data writing is not performed even if the data is received, so long as the high level is received as the mask signal. In the case of “write” (WR), the data corresponding to the low-level of the mask signal is written, since it is secured that the data is received. That is to say, when the write operation is not performed, data in a semiconductor memory device sustains its state, and when the write operation is performed, it is so performed by writing pertinent data in the case the write command is recognized. It is thus prevented to perform the write operation in spite of not receiving or transferring data. FIG. 10A illustrates a state in which only the mask receive timing in the operational mode 4 fluctuates, but in actual cases, the timings for the data transfer GD2 (in the operational modes 2a and 3a), the data write GD3 (in the operational modes 1 to 2a), and the data receive GD1 (in the operational modes 2a and 3a) also fluctuate. However, even if those positions shift, “no write” (No WR) does not turn into “write” (WR), and “write” (WR) does not turn into “no write” (No WR). The malfunction period can be limited within the fluctuation in the mask receive timing (in operational mode 4). The same way holds true for the case in FIG. 16. In FIG. 16, if the timing boundary of the data receive GD1 fluctuates in the similar extent to the mask receive GM1, and is set in the region of the operational mode 4, the positional variations of the data receive GD1 due to such fluctuations extend into the region of the operational mode 5. Accordingly, the data to be written with the write operation becomes unstable, resulting in extension of the data corruption into the region of the operational mode 5. This also occurs where the timing boundary of the data write GD3 set in the operational modes 2c to 2d is set in the region of the operational mode 4, and the case where the timing boundary of the data transfer GD2 set in the operational modes 1 to 2c is set in the region of the operational mode 4. Accordingly, in order to minimize such timings as in which the erroneous writings are performed, an appropriate mask control is carried out in the case that the data write GD3 is performed, such that data corruptions are restricted, and a delay in the write cycle operation, where the write command occurs behind time, can be prevented. FIG. 19A shows the address, the chip enable signal /CE1, the write enable signal /WE, the upper byte mask signal /UB, and the lower byte mask signal /LB. The cycles C1, C2, and so forth are determined depending on the switching of the address. FIG. 19B shows a write operation example of the memory device in the referential example in FIG. 4, by relating itself to FIG. 19A. From the falling edge of the signal webdz which has caused a delay in the falling of the write enable signal /WE, the pulse of the signal wrpz is generated. In the referential example, the delay in the falling edge of the signal webdz should be made long so as not to cause data corruption. This delays the commencement of the write operation, and the ending of the signal rasz showing the core operation also delays, resulting in a delay in the write operation cycle. As described above, when preventing data corruption with “no write” (No WR), in the referential example, the occurrence of the data write command needs to be controlled. However, this leaves a demerit in which a delayed occurrence of the write operation causes an extension of the write cycle time. FIG. 19C shows the write operation of the memory device of the present embodiment in FIG. 6, by relating itself to FIG. 19A. From the falling edge of the signal webdz which delayed the falling of the write enable signal /WE, the pulse of the signal wrpz is generated. However, this delayed time can be shortened. By shortening the delayed time, the write operation commencement can be made earlier, the ending of the signal rasz showing the core operation becomes earlier, and the write operation cycle becomes quicker. In the present embodiment, data corruption can be prevented without having to delay the write operation. FIG. 20 is a flowchart showing a processing example of the write operation of the present embodiment. This flowchart illustrates the processing where there is an inputting of a state that violates the tBW specification (a state in which the tBS in FIG. 9 is a negative value). In the step S2001, it is checked whether the data write GD3 is going to be performed or not. If it is to be performed, a step S2002 follows, and if it is not performed, a step S2006 follows. In the step S2002, it is checked whether the data transfer GD2 is going to be performed or not. If it is to be performed, a step S2003 follows, and if it is not performed, a preceding data is going to be reused, causing data corruption. That is to say, where the data write GD3 is performed, the data transfer GD2 always has to be precedently performed in the same cycle. In the step S2003, it is checked whether the mask receive GM1 of the illegal byte is high level or low level. If it is high level, writing to memory cell is not performed, so that a step S2004 follows. If it is low level, an erroneous data is written to the memory cell, so that the data is corrupted. In the step S2004, it is checked whether the data receive GD1 is to be performed or not. Regardless of performing or non-performing, a step S2005 follows, and in the following cycle, the illegal byte is masked and the write operation is performed. That is to say, the performing or the non-performing of the data receive GD1 does not matter. Because of the masking, the data of the data bus can be any data. In a step S2006, it is checked whether the data transfer GD2 is to be performed or not. Regardless of performing or non-performing, a step S2007 follows. That is to say, the data transfer GD2 does not need to be performed. In the step S2007, it is checked whether the mask receive GM1 is to be performed or not. If it is not to be performed, a step S2008 follows. If it is to be performed, the mask signal in the buffer is corrupted, resulting in data corruption. In the step S2008, it is checked whether the data receive GD1 is to be performed or not. If it is not to be performed, a step S2009 follows. If it is to be performed, the data in the buffer is corrupted, resulting in data corruption. In the step S2009, a proper write data can be maintained. As described above, data corruption occurs if one of the following conditions are violated: (1) to be able to perform the data transfer GD2 without having to perform the data write GD3; (2) not to perform the data receive GD1 if the data write GD3 is not performed; and (3) not to receive a low-level-state mask signal. In the present embodiment, data corruption can be prevented by not violating the above-listed points. By finely designing settings on priorities among the data write, mask receive, data receive, and data transfer, the possibility of performing erroneous writing can be substantially reduced. Accordingly, the write-cycle-affecting measure, in which the occurrence of the write command is delayed, does not need to be taken. By establishing the priorities on the controls of the data receive and data transfer, the possibility of data corruption is reduced. Even if a write command whose length falls short of the normal length is introduced because of a mask control, a delay in the write operation or the data corruption can be prevented. When the write command whose length falls short of the normal length is introduced into a semiconductor memory device, data corruption due to the erroneous writing can be prevented without extending the cycle time, in such a manner that the control is performed by establishing the pulse occurring priorities among data write, mask receive, data receive, and data transfer. The write operation is performed by synthesizing the write enable signal /WE (write basic signal) and the byte mask signals /UB and /LB, and the data receive and the data transfer are carried out with the respective edge pulses of the rising and the falling. The write command pulse and the mask receive pulse are generated based on the falling of the synthesized signal of the signals /WE, /UB, and /LB. The write operation is in the late-write architecture in which the writing to the memory cell is performed upon the falling of the synthesized signal of the signals /WE, /UB, and /LB. The probability of the data write pulse occurrence is lower than that of the data transfer pulse, and by securing the occurrence of the data transfer pulse upon performing of the data write, the data corruption is prevented. In the case where a write command whose length falls short of the normal length is introduced, the data corruption is prevented in such a manner that the mask becomes high level when the data receive pulse occurs. When the write command whose length falls short of the normal length is introduced, the data receive pulse is controlled not to be more likely to occur than the data transfer pulse, so as not to cause data corruption by occurrences of the data receive pulse and the data transfer pulse at a uniform timing. By using the mask signal for preventing data corruption, the data is made such that it is not corrupted just because the data write pulse occurs when the write command falling short of the normal length is entered. Accordingly, the data write pulse can be made to easily occur, and the commencement of the write operation and the write operation cycle can be shortened. When the write enable signal is activated and thereafter the data mask signal changes, depending on the time period therebetween, data is not inputted to the first buffer by control of the data receive gate, and at the same time data is inputted to the second buffer by control of the data transfer gate. As a result, data corruption is prevented which occurs upon partial overlapping of the data transfer time and the data receiving time, where a subsequent data is erroneously inputted to the second buffer through the data receive gate and the data transfer gate at a time when a present data has to be inputted to the second buffer. Such prevention of data corruption can be performed without causing delay in the write operation in the cycle. The present embodiments are to be considered in all respects as illustrative and no restrictive, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention This invention relates to a memory device and, more particularly, to a memory device to write data to a memory cell according to a write enable signal and a data mask signal. 2. Description of the Related Art There are memory devices which write data to memory cell according to a write enable signal and a data mask signal. These memory devices receive data in a buffer at a present cycle, and transfer and write the data in a subsequent cycle, according to the write enable signal and the data mask signal. In such a memory device, it is necessary to prevent erroneous writing of data due to writing malfunction. There, a delay in a write operation also has to be avoided. In a semiconductor memory device, when a write operation is externally directed in a last-second state of whether to perform writing or not, one of (1) not to perform writing, and (2) to perform writing and receive data or a masking state correctly, has to be executed. When performing the write operation, receiving of unwanted mask data which is being transferred, or writing of a prior data using another address without receiving new data, must be avoided. However, any measure to control occurrence of write commands results in a slow-down of a write operation and a write cycle. Another conventional arts are also published in the following patent documents 1 to 3. [Patent Document 1] Japanese Patent Application Laid-open No. Hei 11-7770 [Patent Document 2] Japanese Patent Application Laid-open No. 2003-7060 [Patent Document 3] Japanese Patent Application Laid-open No. 2001-351377 | <SOH> SUMMARY OF THE INVENTION <EOH>It is an object of the present invention to provide a memory device to prevent data corruption without causing delay in write operation. According to an aspect of the present invention, is provided a memory device including: a data receive gate to buffer data inputted by gate control in a first buffer; a data transfer gate to input the data of the first buffer and buffer the data in a second buffer by gate control; a data write gate to output the data of the second buffer to a data bus by gate control; a memory cell to write and store the data on the data bus; a selector not to connect the data bus to a memory cell in the case of masking through a data mask signal, and to connect the data bus to the memory cell when the masking is released through the data mask signal; and a control circuit to, according to a write enable signal and a data mask signal, input data by controlling the data receive gate in a present cycle, and in a subsequent cycle input the data of the first buffer in the second buffer by controlling the data transfer gate and output the data of the second buffer to a data bus by controlling the data write gate. In the control circuit, data is inputted to the first buffer by controlling the data receive gate, while data is inputted to the second buffer by controlling the data transfer gate, in a certain cycle according to a time period from an activation of the write enable signal to a change in the data mask signal. | 20040419 | 20050920 | 20050512 | 99380.0 | 0 | NGUYEN, HIEN N | MEMORY DEVICE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,826,503 | ACCEPTED | Method for preventing activation of malicious objects | A method for preventing activating a malicious object passing through a checkpoint, and decreasing the overall inspection delay thereof, the method comprising the steps of: (a) at the checkpoint, creating an envelope file, being an executable file comprising: the object; code for extracting the object from the envelope file; and an indicator for indicating the integrity of the object; (b) forwarding the envelope file instead of the object toward its destination, while holding at least a part of the envelope file which comprises the indicator; (c) inspecting the object; and (d) setting the indicator on the envelope file to indicate the inspection result thereof, and releasing the rest of the envelope file. | 1. A method for preventing activating a malicious object passing through a checkpoint, and decreasing the overall inspection delay thereof, the method comprising the steps of: a. at said checkpoint, creating an envelope file, being an executable file comprising: said object; code for extracting said object from said envelope file; and an indicator for indicating the integrity of said object; b. forwarding said envelope file instead of said object toward its destination, while holding at least a part of said envelope file which comprises said indicator; c. inspecting said object; d. setting said indicator on said envelope file to indicate the inspection result thereof, and e. releasing the rest of said envelope file. 2. A method according to claim 1, wherein said checkpoint is selected from a group comprising: a gateway server, a proxy server. 3. A method according to claim 1, wherein said code is auto-executable. 4. A method according to claim 1, wherein the name of said envelope file is identical to the name of the inspected object. 5. A method according to claim 1, wherein the name of said envelope file differs than the name of the inspected object. 6. A method according to claim 1, wherein said indicator is selected from a group comprising: a CRC of at least one part of said envelope file, a CRC of at least one part of said inspected object, a checksum of at least one part of said envelope file, a checksum of at least one part of said inspected object, a value stored within said envelope file, absence of a part of said envelope file, absence of a part of said object. 7. A method according to claim 1, wherein at least a part of said object is secured. 8. A method according to claim 1, wherein at least a part of said envelope file is secured. 9. A method according to claim 1, wherein said indicator is stored within the last part of said envelope file. 10. A method according to claim 1, wherein said envelope file further comprises code for displaying an acknowledgment. 11. A method according to claim 10, wherein said acknowledgment indicates integrity of said object. | FIELD OF THE INVENTION The present invention relates to the field of detecting viruses and other malicious forms in a checkpoint (e.g. gateway). More particularly, the invention relates to a method for preventing activation of malicious objects while decreasing the overall inspection time. BACKGROUND OF THE INVENTION The term “gateway” refers in the art to a bridge between two networks. For each network, the gateway is a point that acts as an entrance to another network. From the implementation point of view, a gateway is often associated with both a router, which knows where to direct a given packet that arrives to the gateway and a switch, which provides the packet with the actual path in and out of the gateway. Due to its nature, the gateway to a local network is a proper point for checking out objects (e.g. files and email messages) that pass through it, in order to detect viruses and other forms of maliciousness (“inspection”) before reaching the user. As a filtering facility, a gateway server has to deal with two contradicting objects: on the one hand, it has to hold a file that reaches the gateway in its path from a source to a destination until the inspection indicates it is harmless and thereby prevents its execution on the destination site, on the other hand holding a file at the gateway server until the inspection process terminates which results in a bottleneck to data traffic passing through the gateway. Inspection activity has a substantial influence on the traffic speed through a gateway. U.S. patent application Ser. No. 10/002,407, titled as Security Router, deals with this problem by skipping the inspection of trusted files. According to this invention, since multimedia files (e.g. JPG files) do not comprise executable code (according to their definition), these files are not inspected, thereby diminishing the delay caused by the inspection process. U.S. patent application Ser. No. 09/498,093, titled as “Protection of computer networks against malicious content”, deals with this problem by holding in a checkpoint (e.g. a gateway) only a part of the file, such as the last packet of the file, and releasing it once the file has been indicated as harmless. This way the majority of the file is not delayed at the gateway, but its execution at the destination site cannot be carried out until the last part reaches the destination. This solution is applicable only for files that in order to be executed or activated, the whole file has to be available on the executing platform. However, if the executing platform activates a file even in the case where only a part of the file is available, the executing platform is exposed to viruses and other malicious forms. Furthermore, some inspection methods, such as CRC-based methods, require that the whole file be available during the inspection process. Files that should be fully accessible for inspection, may cause a substantial delay to the traffic through a checkpoint since the inspection can start only after the whole file is accessible to the inspection facility. Thus, in this case, the parts of a file should be accumulated and held at the inspection point until the inspection indicates that it is harmless, and only then the file may be “released” to its destination. It is an object of the present invention to provide a method for preventing activation of malicious objects. It is a further object of the present invention to provide a method for preventing from a checkpoint the activation of malicious objects on the executing platform. It is a still further object of the present invention to provide a method for inspecting a file on a checkpoint, by which the delay thereof is decreased in comparable to the prior art. Other objects and advantages of the invention will become apparent as the description proceeds. SUMMARY OF THE INVENTION A method for preventing activating a malicious object passing through a checkpoint, and decreasing the overall inspection delay thereof, the method comprising the steps of: (a) at the checkpoint, creating an envelope file, being an executable file comprising: the object; code for extracting the object from the envelope file; and an indicator for indicating the integrity of the object; (b) forwarding the envelope file instead of the object toward its destination, while holding at least a part of the envelope file which comprises the indicator; (c) inspecting the object; and (d) setting the indicator on the envelope file to indicate the inspection result thereof, and releasing the rest of the envelope file. According to a preferred embodiment of the invention, the envelope file is an auto-executable file. According to one embodiment of the invention, the name of the envelope file is identical to the name of the inspected object. According to another embodiment of the invention, the name of the envelope file differs than the name of the inspected object. The indicator may be a CRC of a part of the envelope file, a CRC of a part of the inspected object, a checksum of a part of the envelope file, a checksum of a part of the inspected object, a value stored within the envelope file, absence of a part of the envelope file, absence of a part of the inspected object, and so forth. According to a preferred embodiment of the invention, the envelope file further comprises code for displaying an acknowledgment to the user for indicating the integrity of the inspected object. Typically the acknowledgment is displayed only when the inspected objects is indicated as malicious. BRIEF DESCRIPTION OF THE DRAWINGS The present invention may be better understood in conjunction with the following figures: FIG. 1 schematically illustrates a system that may be used for implementing the present invention. FIG. 2 schematically illustrates the parts of an envelope file, according to a preferred embodiment of the present invention. FIG. 3 is a flowchart of a process for creating an envelope file, according to a preferred embodiment of the invention. FIG. 4 is a flowchart of a process carried out by an envelope file on the destination site, according to a preferred embodiment of the invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The term “checkpoint” refers herein to a point on a data channel or data junction in which the passing data is inspected. For example, a gateway is a suitable place for a checkpoint. FIG. 1 schematically illustrates a system that may be used for implementing the present invention. The computers 21 are connected to the local area network 20. The local area network 20 is connected to the internet 10. The gateway server 30 is interposed between the local area network 20 and the internet 10. The Internet server 40 hosts web sites. A browser being executed on a computer 21 that addresses to the web site hosted by the internet server 40 cause files to be transferred from the internet server 40 to the computer 21 through the gateway server 30. As mentioned above, a gateway server that inspects data that is transferred through it, has to deal with two contradicting objects: on the one hand, it has to hold an inspected object until its harmlessness is indicated, on the other hand holding the file at the gateway may cause a bottleneck to the data traffic passing through the gateway. This problem is solved by the present invention. The present invention allows passing a file toward its destination while inspecting the file, and still preventing the activation of the file at the destination site until its integrity is indicated. This is carried out as follows: instead of forwarding the original file to its destination, a substitute file which comprises the original file is constructed and transmitted to the destination. The substitute file is also referred herein as envelope file. According to one embodiment of the invention, the envelope file is an executable which comprises the following parts: the original file; an indicator about the integrity of the original file; and an executable part, upon which execution extracts the original file, and executes it. At the destination site, the envelope file is executed instead of the original file. On this execution, if the integrity indicator indicates that the original file is harmless, the original file is extracted from the envelope file and executed. The integrity indicator can be the CRC (Cyclic Redundancy Checks) or checksum of the envelope file, the CRC or checksum of the original file, a bit within the envelope file, a value stored within the envelope file (in a byte, a bit, etc.), and so forth. In order to prevent forge of the envelope file, the indicator and/or the envelope file can be secured (e.g. encrypted, digitally signed with the original or envelope file, and so forth). For example, in the case where the integrity of the original file is indicated at the gateway, the gateway sends the true CRC value of the original file. In case the original file is indicated as comprising malicious content, the gateway sends a wrong CRC value of the original file. As well, other indicators can be used. It should be noted that the envelope file performs two operations: on the one hand it is an executable file, which is loaded into the computer's memory for executing, but on the other hand it is treated as a data file. FIG. 2 schematically illustrates the parts of an envelope file, according to a preferred embodiment of the present invention. The envelope file 50 comprises: an executable part 51; the original file 52; and an integrity indicator 53. FIG. 3 is a flowchart of a process for creating an envelope file, according to a preferred embodiment of the invention. The process starts at block 100, where a packet of a file sent from a source to a destination reaches to a gateway server (or, generally, a checkpoint). From block 101, if the packet is the first packet of a file then the process continues with block 102, where a new envelope file is created, and therefrom with block 103, where an executable code is added to the created envelope file, and therefrom to block 104. The operation of the executable code is detailed in the description of FIG. 4. At block 104, the packet is added to the envelope file. At block 105, a copy of the packet is sent to the inspection facility for inspection. At block 106, the accumulated parts of the envelope file are sent to the destination. From block 107, if the reached packet is the last packet of the file, then an integrity indicator is added to the envelope file, and the last accumulated parts of the envelope file are sent to the destination. The integrity indicator is received from the inspection facility which operates at the gateway. If the received packet is not the last packet of the original file, then when a new packet of the original file will reach to the gateway server, the process will continue from block 100. In this example it was assumed that the packets of a file reach the gateway in consecutive order, however, as known to a person of ordinary skill in the art, this is not necessarily true, since each packet may be redirected to its destination through a different path. Thus, when adding a packet of the original file to the envelope file, the order should be taken into consideration. However, according to a preferred embodiment of the invention, the indicator is stored within the last part of the envelope file. This way usually (but not always) the integrity indicator will be the last to reach the destination. FIG. 4 is a flowchart of a process carried out by an envelope file on the destination site, according to a preferred embodiment of the invention. At block 200 the envelope file is executed. At block 201, the executed envelope program gets the integrity indicator. As mentioned above, the envelope file is also used as a data file which comprises the original file and an integrity indicator. From block 202, if according to the integrity indicator the original file is malicious, then at block 209 the envelope file acknowledges the user (e.g. by displaying a corresponding message), and the execution of the envelope file terminates, otherwise control continues with block 203. At block 203, the envelope program extracts the original file from the envelope file. At block 204, the original file is executed. At this point the envelope executable can terminate. At block 205, since the envelope file is not required anymore, it can be replaced by the original file. Typically the inspected object is an executable, however it should be noted that the invention can also be implemented for other file types, whether it is an executable or not, or whether it is attached to an email message or returned in an FTP or HTTP session. It should also be noted that although the references herein are to a gateway, the invention can be implemented to any kind of checkpoint, e.g. an arbitrary point on a network, a server of an Internet service provider, a mail server, and so forth. Those skilled in the art will appreciate that the invention can be embodied by other forms and ways, without losing the scope of the invention. The embodiments described herein should be considered as illustrative and not restrictive. | <SOH> BACKGROUND OF THE INVENTION <EOH>The term “gateway” refers in the art to a bridge between two networks. For each network, the gateway is a point that acts as an entrance to another network. From the implementation point of view, a gateway is often associated with both a router, which knows where to direct a given packet that arrives to the gateway and a switch, which provides the packet with the actual path in and out of the gateway. Due to its nature, the gateway to a local network is a proper point for checking out objects (e.g. files and email messages) that pass through it, in order to detect viruses and other forms of maliciousness (“inspection”) before reaching the user. As a filtering facility, a gateway server has to deal with two contradicting objects: on the one hand, it has to hold a file that reaches the gateway in its path from a source to a destination until the inspection indicates it is harmless and thereby prevents its execution on the destination site, on the other hand holding a file at the gateway server until the inspection process terminates which results in a bottleneck to data traffic passing through the gateway. Inspection activity has a substantial influence on the traffic speed through a gateway. U.S. patent application Ser. No. 10/002,407, titled as Security Router, deals with this problem by skipping the inspection of trusted files. According to this invention, since multimedia files (e.g. JPG files) do not comprise executable code (according to their definition), these files are not inspected, thereby diminishing the delay caused by the inspection process. U.S. patent application Ser. No. 09/498,093, titled as “Protection of computer networks against malicious content”, deals with this problem by holding in a checkpoint (e.g. a gateway) only a part of the file, such as the last packet of the file, and releasing it once the file has been indicated as harmless. This way the majority of the file is not delayed at the gateway, but its execution at the destination site cannot be carried out until the last part reaches the destination. This solution is applicable only for files that in order to be executed or activated, the whole file has to be available on the executing platform. However, if the executing platform activates a file even in the case where only a part of the file is available, the executing platform is exposed to viruses and other malicious forms. Furthermore, some inspection methods, such as CRC-based methods, require that the whole file be available during the inspection process. Files that should be fully accessible for inspection, may cause a substantial delay to the traffic through a checkpoint since the inspection can start only after the whole file is accessible to the inspection facility. Thus, in this case, the parts of a file should be accumulated and held at the inspection point until the inspection indicates that it is harmless, and only then the file may be “released” to its destination. It is an object of the present invention to provide a method for preventing activation of malicious objects. It is a further object of the present invention to provide a method for preventing from a checkpoint the activation of malicious objects on the executing platform. It is a still further object of the present invention to provide a method for inspecting a file on a checkpoint, by which the delay thereof is decreased in comparable to the prior art. Other objects and advantages of the invention will become apparent as the description proceeds. | <SOH> SUMMARY OF THE INVENTION <EOH>A method for preventing activating a malicious object passing through a checkpoint, and decreasing the overall inspection delay thereof, the method comprising the steps of: (a) at the checkpoint, creating an envelope file, being an executable file comprising: the object; code for extracting the object from the envelope file; and an indicator for indicating the integrity of the object; (b) forwarding the envelope file instead of the object toward its destination, while holding at least a part of the envelope file which comprises the indicator; (c) inspecting the object; and (d) setting the indicator on the envelope file to indicate the inspection result thereof, and releasing the rest of the envelope file. According to a preferred embodiment of the invention, the envelope file is an auto-executable file. According to one embodiment of the invention, the name of the envelope file is identical to the name of the inspected object. According to another embodiment of the invention, the name of the envelope file differs than the name of the inspected object. The indicator may be a CRC of a part of the envelope file, a CRC of a part of the inspected object, a checksum of a part of the envelope file, a checksum of a part of the inspected object, a value stored within the envelope file, absence of a part of the envelope file, absence of a part of the inspected object, and so forth. According to a preferred embodiment of the invention, the envelope file further comprises code for displaying an acknowledgment to the user for indicating the integrity of the inspected object. Typically the acknowledgment is displayed only when the inspected objects is indicated as malicious. | 20040419 | 20080610 | 20051020 | 73228.0 | 2 | LIPMAN, JACOB | METHOD FOR PREVENTING ACTIVATION OF MALICIOUS OBJECTS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,826,857 | ACCEPTED | Apparatus for continuous joining and/or welding of material webs using ultrasound | An apparatus for continuously bonding and/or welding material webs by means of ultrasound, having an ultrasonic horn configured as a rotating roller, an anvil radially opposite the rotating roller, an amplitude transformer set axially on the rotating roller, an ultrasonic converter attached to the amplitude transformer with an energy supply, where the length l of the rotating roller equals a λ/2 wave or a multiple thereof (l=x·λ/2). | 1. An apparatus for the continuous bonding and/or welding of material webs by means of ultrasound having an ultrasonic horn configured as a rotating roller, an anvil disposed opposite the rotating shaft, an amplitude transformer set axially on the rotating shaft, and an ultrasonic converter attached to the amplitude transformer with an energy supply, characterized in that the length of the rotating roller equals one of a lambda-half wave of the imposed oscillation and a multiple thereof. 2. The apparatus in accordance with claim 1, wherein radial bearings are disposed between the amplitude transformer and the rotating roller. 3. The apparatus in accordance with claim 1, wherein an amplitude transformer and an ultrasonic converter are furnished on both sides of the rotating roller. 4. The apparatus in accordance with claim 1, wherein the anvil is a rotating counter-roller. 5. The apparatus in accordance with claim 1, wherein the outer surface of one of the rotating roller and the counter-roller is one of smooth and patterned. 6. The apparatus in accordance with claim 1, wherein the anvil is fixed. 7. The apparatus in accordance with claim 6, wherein the anvil extends in a tangential direction respective to the rotating roller. 8. The apparatus in accordance with claim 1, wherein the depth of the working gap between the rotating roller and the anvil is adjustable. 9. The apparatus in accordance with claim 1, wherein the pressure exerted by the rotating roller on the material web is adjustable. 10. The apparatus in accordance with claim 1, wherein the rotating roller is formed by a hollow shaft with trunnions. 11. The apparatus in accordance with claim 1, wherein the rotating roller can be one of cooled and heated. 12. The apparatus in accordance with claim 4, wherein the counter-roller is configured as an active roller with an amplitude transformer and an ultrasonic converter attached thereto. 13. The apparatus in accordance with claim 1, wherein at least two rotating rollers, arranged in tandem, contact the anvil. 14. The apparatus in accordance with claim 13, wherein the two rollers arranged in tandem are offset to each other in the axial direction by an amount. 15. The apparatus in accordance with claim 14, wherein the amount equals a lambda-half wave of the imposed oscillation. 16. The apparatus in accordance with claim 1, wherein the diameter of the rotating roller is partially waisted. 17. The apparatus in accordance with claim 16, wherein the depth of the waist equals one part of a lambda-half wave of the imposed oscillation. 18. The apparatus in accordance with claim 1, wherein a diameter of the rotating roller is made thicker such that pressure is equally distributed along its length. 19. The apparatus in accordance with claim 1, wherein the rotating roller has a swelling. 20. The apparatus in accordance with claim 1, wherein a change in diameter of the rotating roller corresponds to a bending line. 21. The apparatus in accordance with claim 4, wherein axes of the rotating roller and the counter-roller anvil are skewed relative to each other. 22. The apparatus in accordance with claim 1, wherein the anvil is one of a knife and a blade. | BACKGROUND The invention relates to an apparatus for the continuous bonding and/or welding of material webs using ultrasound, having an ultrasonic horn configured as a rotating roller, an anvil disposed radially opposite the rotating roller, an amplitude transformer set axially on the rotating roller, and an ultrasonic converter with an energy supply attached to the amplitude transformer. It is known that for the continuous welding and/or bonding of material webs. The material webs are passed through a rotating roller and a fixed or similarly rotating roller and thereby processed. With fixed ultrasonic horns, large material widths can be covered, but a frictional force arises between the ultrasonic horn and the moving material web, negatively affecting the welding result. In addition, the frictional force causes heating of both the material webs and of the ultrasonic horn, thereby changing the pre-set gap. The above described disadvantage of friction can be prevented with rotating ultrasonic horns, but only narrow-width welds can be performed. From U.S. published application 2002/030157, an ultrasonic horn is known with a width that is smaller than lambda-half. This also applies to the devices known from U.S. Pat. Nos. 5,707,483 and 6,547,903. SUMMARY The object of the invention is therefore to prepare an apparatus for the continuous bonding and/or welding of material webs, with which wide material webs can be processed. This object is achieved with an ultrasonic horn configured as a rotating roller whose length is equal to a lambda-half wave of the imposed oscillation or a multiple thereof. In the inventive apparatus, the ultrasonic horn configured as a rotating roller has a length which equals lambda-half or a multiple of lambda-half of the imposed oscillation. The length of the rotating roller essentially depends, therefore, on the material used and the desired operating frequency. By multiplying the length of the rotating roller to a multiple of lambda-half of the oscillation, extremely wide material webs can be processed without having to use several individual ultrasonic horns for this purpose. The material webs can also be dried with the inventive apparatus. In a further development, radial bearings are furnished between the amplitude transformer and the rotating roller. These radial bearings are located particularly in a nodal point of the longitudinal oscillation, so that no or negligibly small oscillation amplitudes affect the bearings. An amplitude transformer and an ultrasonic converter are preferably furnished on both sides of the rotating roller. Depending on the requisite energy with which the material webs are to be welded or bonded to each other, either one converter or two converters can be furnished, with the amplitude transformers located so that the converters can be changed, specifically bolted in. The converters can be of the same material as the rotating roller. In one aspect, the two amplitude transformers and the roller are combined in a single component. Greater strength is achieved thereby, and there is no danger of the amplitude transformers becoming detached from the roller. The anvil is preferably a rotating counter-roller. Two counter-rotating rollers offer the advantage that friction is limited to a minimum and that the material webs are handled very gently without the processing leading to format changes. In one variation, the counter-roller is configured as an active roller and possesses two amplitude transformers and at least one converter. Each roller has its own converter. The outer surface of either the rotating roller or the counter roller can be smooth or patterned. With a patterned roller, a texture can be embossed on the material webs, which results in an even tighter bond. The texture can be a nubby texture, a waffle texture, linear texture or a fantasy pattern. In another aspect, the anvil is fixed and configured in particular as a knife, blade, or the like. The knife, blade or the like extends in a tangential direction, so that the welding or bonding of the material webs to each other takes place in linear fashion. The gap width of the rotating roller and the anvil is adjustable in a known way. The setting can be regulated, so that the gap width is kept constant. This is of advantage, particularly with temperature changes, since the temperature changes do not then manifest themselves in a change in the gap width. In a further development, the pressure exerted on the material web by the rotating roller can be adjusted. In particular, a pressure regulator can be furnished, so that consistent pressure is always imposed on the material webs. In a preferred aspect, the rotating roller is formed by a hollow shaft with a trunnion at each end. A ultrasonic horn configured in this way is first of all light, secondly it possesses outstanding oscillation properties, since the antinode of the transverse oscillation at a length of lambda-half lies in the middle of the hollow shaft. The rotating roller can advantageously be cooled or heated. Heat can thereby be drawn off or introduced selectively, keeping welding conditions constant. In a preferred aspect, at least two rotating rollers lie against the anvil, arranged in tandem, where in particular the two rollers in tandem are offset to one another in the axial direction by an amount (Δ1). This provides a simple way of being able to increase the energy input and improve the distribution of energy. The amount is a lambda-quarter wave of the imposed oscillation (Δ1=λ/4). In accordance with the invention, the diameter (D) of the rotating roller is partially waisted where, in particular, the depth of the waist (E) equals one part of a lambda-half wave of the imposed oscillation (E=|x|·λ/2). In its oscillating state, the rotating roller temporarily assumes the form of a cylinder, whereby better pressure distribution is achieved. The rotating roller is advantageously made thicker in diameter such that contact pressure is evenly distributed along its length. This measure similarly contributes to an equalization of pressure distribution along the entire length of the roller, since the deformation of the roller by the contact pressure is compensated. This is specifically achieved by incorporating a bulge in the rotating roller. The change in diameter of the rotating roller corresponds exactly to the bending line. A further measure to equalize the distribution of pressure is that the axis of the rotating roller and that of the counter-roller anvil are skewed to each other. BRIEF DESCRIPTION OF THE DRAWING Additional advantages, features and details of the invention can be found in the following description, in which particularly preferred embodiments are described in detail with reference to the drawing. The features depicted in the drawing and mentioned in the claims and the description can be essential to the invention individually or in any combination. In the drawing: FIG. 1 shows a perspective view of a preferred aspect of the invention with an anvil configured as a counter-roller; FIG. 2 shows a section along line II-II in FIG. 1; FIG. 3 shows a longitudinal section through the rotating roller; FIG. 4 shows a side view of the ultrasonic horn with amplitude transformers; FIG. 5 is a diagram showing the oscillations running in the transverse and longitudinal direction; FIG. 6 shows a perspective view of an aspect with two rotating rollers; FIG. 7 shows a side view in the direction of arrow VII in FIG. 6; FIG. 8 shows an aspect with two rotating rollers offset to each other; FIG. 9 shows a side view of an aspect with a rotating roller having waists; FIG. 10 shows a plan view of an aspect in which the axes of the rotating roller and the counter-roller are skewed relative to each other; FIG. 11 is a side view in the direction of arrow XI in FIG. 10; and FIG. 12 shows an enlarged reproduction of the section XII in accordance with FIG. 11. BRIEF DESCRIPTION In FIG. 1, two rotating components can be seen, identified in general by reference numbers 10 and 12, between which two or more material webs 14 and 16 are being fed, wherein the two material webs 14 and 16 are bonded and/or welded together are they pass through a working gap 18. The pass-through direction is indicated by the arrow 20. The component 10 possesses a central rotating roller 22, to which amplitude transformers 24 are attached on both sides, with radial bearings 26 furnished on said transformers. The amplitude transformers 24 are coupled to ultrasonic converters 28 through which a mechanical vibration can be generated in the longitudinal direction, i.e., in the direction of the double arrow 30. Rotary couplers 32 are furnished on the end faces of the ultrasonic converters 28 through which the ultrasonic converters 28 are provided with energy. A counter-roller 34, which is similarly carried rotatably on radial bearings 36, is disposed opposite the rotating roller. The surface of the counter-roller 34 has ribs 50 running in the longitudinal direction which impart a texture to the counter-roller which is transferred to the material webs 14 and 16 when they are bonded. In FIG. 2, the arrows 38 and 40 indicate the rotational directions of the rotating roller 22 and the counter-roller 34. The rotary coupler 32 can also be seen, through which the ultrasonic converter 28 is supplied with energy. FIG. 3 shows a longitudinal section through the rotating roller 22, which in the aspect shown is formed by a hollow shaft 42 which is closed by trunnions 44. The amplitude transformers 24 (not shown in FIG. 3) are attached to these trunnions 44. FIG. 4 shows a side view of the rotating roller 22 with the laterally attached amplitude transformers 24 and the radial bearing 26. In the aspect shown, the length l of the rotating roller 22 equals lambda-half (λ/2) of the oscillation imposed by the amplitude transformers 24. The two radial bearings 26 are spaced lambda-quarter (λ/4) from the end faces of the rotating roller 22 and the two amplitude transformers 24 extend by lambda-quarter (λ/4) beyond the radial bearings 26. The diagram shown in FIG. 5 shows the longitudinal oscillation, reference numeral 46, which is generated by the amplitude transformers 24. The transverse oscillation runs offset to it by lambda-quarter (λ/4), causing an oscillation of the rotating roller in the radial direction by which the welding process is carried out. In the aspect in FIG. 4, the length l of the rotating roller is lambda-half (λ/2), although the length can also be a multiple thereof, as indicated in FIG. 3. In this way it is possible to bond material webs 14 and 16 whose width is greater than lamda-half. In FIGS. 6 through 8, two rotating rollers 22 are arranged around the counter-roller 34, with the rotating rollers 22 disposed behind one another and offset by an angle of 50° to 60° and additionally offset to each other in the axial direction by an amount of Δ1=λ/4, which is shown clearly in FIG. 8. The two rotating rollers 22 can be configured identically and are driven by the same frequency generator or oscillate in the same direction. FIG. 9 shows an aspect in which the rotating roller 22 has a waist E whereby the diameter D is selectively reduced over the length of the roller 22. The transverse oscillation 48 of the roller 22 is also shown diagrammatically in FIG. 9. It can be seen that the waist E is always deepest where an oscillation antinode is located. The amount of the waist E is thus the product of a constant and lambda-half (E=|x|·λ/2). When the rotating roller 22 is set oscillating, it temporarily assumes the form of a cylinder. FIGS. 10 through 12 show a variation in which the one of the two rotating rollers 22 is set at an angle, so that its longitudinal axis 52 is skewed to the longitudinal axis 54 of the counter-roller 34. The skew angle is identified in FIG. 10 by α. The section identified in FIG. 11 by XII is shown enlarged in FIG. 12, and it is clearly recognizable that the contact line of the two rollers does not run parallel to their axes but obliquely. The contact pressure can thereby be equalized. | <SOH> BACKGROUND <EOH>The invention relates to an apparatus for the continuous bonding and/or welding of material webs using ultrasound, having an ultrasonic horn configured as a rotating roller, an anvil disposed radially opposite the rotating roller, an amplitude transformer set axially on the rotating roller, and an ultrasonic converter with an energy supply attached to the amplitude transformer. It is known that for the continuous welding and/or bonding of material webs. The material webs are passed through a rotating roller and a fixed or similarly rotating roller and thereby processed. With fixed ultrasonic horns, large material widths can be covered, but a frictional force arises between the ultrasonic horn and the moving material web, negatively affecting the welding result. In addition, the frictional force causes heating of both the material webs and of the ultrasonic horn, thereby changing the pre-set gap. The above described disadvantage of friction can be prevented with rotating ultrasonic horns, but only narrow-width welds can be performed. From U.S. published application 2002/030157, an ultrasonic horn is known with a width that is smaller than lambda-half. This also applies to the devices known from U.S. Pat. Nos. 5,707,483 and 6,547,903. | <SOH> SUMMARY <EOH>The object of the invention is therefore to prepare an apparatus for the continuous bonding and/or welding of material webs, with which wide material webs can be processed. This object is achieved with an ultrasonic horn configured as a rotating roller whose length is equal to a lambda-half wave of the imposed oscillation or a multiple thereof. In the inventive apparatus, the ultrasonic horn configured as a rotating roller has a length which equals lambda-half or a multiple of lambda-half of the imposed oscillation. The length of the rotating roller essentially depends, therefore, on the material used and the desired operating frequency. By multiplying the length of the rotating roller to a multiple of lambda-half of the oscillation, extremely wide material webs can be processed without having to use several individual ultrasonic horns for this purpose. The material webs can also be dried with the inventive apparatus. In a further development, radial bearings are furnished between the amplitude transformer and the rotating roller. These radial bearings are located particularly in a nodal point of the longitudinal oscillation, so that no or negligibly small oscillation amplitudes affect the bearings. An amplitude transformer and an ultrasonic converter are preferably furnished on both sides of the rotating roller. Depending on the requisite energy with which the material webs are to be welded or bonded to each other, either one converter or two converters can be furnished, with the amplitude transformers located so that the converters can be changed, specifically bolted in. The converters can be of the same material as the rotating roller. In one aspect, the two amplitude transformers and the roller are combined in a single component. Greater strength is achieved thereby, and there is no danger of the amplitude transformers becoming detached from the roller. The anvil is preferably a rotating counter-roller. Two counter-rotating rollers offer the advantage that friction is limited to a minimum and that the material webs are handled very gently without the processing leading to format changes. In one variation, the counter-roller is configured as an active roller and possesses two amplitude transformers and at least one converter. Each roller has its own converter. The outer surface of either the rotating roller or the counter roller can be smooth or patterned. With a patterned roller, a texture can be embossed on the material webs, which results in an even tighter bond. The texture can be a nubby texture, a waffle texture, linear texture or a fantasy pattern. In another aspect, the anvil is fixed and configured in particular as a knife, blade, or the like. The knife, blade or the like extends in a tangential direction, so that the welding or bonding of the material webs to each other takes place in linear fashion. The gap width of the rotating roller and the anvil is adjustable in a known way. The setting can be regulated, so that the gap width is kept constant. This is of advantage, particularly with temperature changes, since the temperature changes do not then manifest themselves in a change in the gap width. In a further development, the pressure exerted on the material web by the rotating roller can be adjusted. In particular, a pressure regulator can be furnished, so that consistent pressure is always imposed on the material webs. In a preferred aspect, the rotating roller is formed by a hollow shaft with a trunnion at each end. A ultrasonic horn configured in this way is first of all light, secondly it possesses outstanding oscillation properties, since the antinode of the transverse oscillation at a length of lambda-half lies in the middle of the hollow shaft. The rotating roller can advantageously be cooled or heated. Heat can thereby be drawn off or introduced selectively, keeping welding conditions constant. In a preferred aspect, at least two rotating rollers lie against the anvil, arranged in tandem, where in particular the two rollers in tandem are offset to one another in the axial direction by an amount (Δ 1 ). This provides a simple way of being able to increase the energy input and improve the distribution of energy. The amount is a lambda-quarter wave of the imposed oscillation (Δ 1 =λ/4). In accordance with the invention, the diameter (D) of the rotating roller is partially waisted where, in particular, the depth of the waist (E) equals one part of a lambda-half wave of the imposed oscillation (E=|x|·λ/2). In its oscillating state, the rotating roller temporarily assumes the form of a cylinder, whereby better pressure distribution is achieved. The rotating roller is advantageously made thicker in diameter such that contact pressure is evenly distributed along its length. This measure similarly contributes to an equalization of pressure distribution along the entire length of the roller, since the deformation of the roller by the contact pressure is compensated. This is specifically achieved by incorporating a bulge in the rotating roller. The change in diameter of the rotating roller corresponds exactly to the bending line. A further measure to equalize the distribution of pressure is that the axis of the rotating roller and that of the counter-roller anvil are skewed to each other. | 20040416 | 20060919 | 20050217 | 96765.0 | 0 | SELLS, JAMES D | APPARATUS FOR CONTINUOUS JOINING AND/OR WELDING OF MATERIAL WEBS USING ULTRASOUND | SMALL | 0 | ACCEPTED | 2,004 |
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10,826,943 | ACCEPTED | METHOD AND DEVICE FOR MEASURING FLUCTUATIONS IN THE CROSS-SECTIONAL AREA OF HAIR IN A PRE-DETERMINED SCALP AREA | The method for isolating an area of hair-bearing skin and measuring a combined cross section of hair in the area comprising the steps of: preparing a pre-measured site on the scalp; isolating a standardized bundle of uncut hair at the site; compressing the bundle of hair with a measurable load while simultaneously measuring the height of the bundle of hair with a piston and cylinder device. One embodiment of the device comprises a body having a slot for receiving a bundle of hair, an anvil positioned adjacent said slot, and a mechanism for causing relative movement between the body having the slot and the anvil thereby to compress a bundle of uncut hair received in the slot against the anvil. | 1. An intravenous catheter introducing device comprising: a barrel having front and rear open ends opposite to each other in a longitudinal direction, and a surrounding barrel wall which interconnects and which is interposed between said front and rear open ends, said surrounding barrel wall including a front smaller-diameter wall portion and a rear larger-diameter wall portion which are opposite to each other in the longitudinal direction and which are proximate to said front and rear open ends, respectively, said surrounding barrel wall having an inner barrel wall surface which surrounds an axis in the longitudinal direction and which confines a passage that is communicated with said front and rear open ends, and an outer barrel wall surface opposite to said inner barrel wall surface in radial directions relative to the axis; a needle cannula having a front segment terminating at a tip end, and a rear connecting end opposite to said front segment along the axis; a needle hub including a front holding portion and a rear shell portion disposed opposite to each other along the axis, said front holding portion being received in said passage so as to be surrounded by said smaller-diameter wall portion, said rear shell portion being inserted into said passage from said rear open end, and being slidable relative to said surrounding barrel wall along the axis between front and rear positions to be proximate to said front open end and said rear open end, respectively, said front holding portion holding said rear connecting end of said needle cannula such that when said rear shell portion is in the front position, said needle cannula is placed in a position of use, where said front segment extends forwardly of said front open end for ready use, and when said rear shell portion is in the rear position, said needle cannula is placed in a disposal position, where said front segment retreats into said passage, said rear shell portion surrounding the axis and defining a flashback chamber which is fluidly communicated with said needle cannula; a releasably retaining member which is disposed to arrest axial movement of said needle hub relative to said barrel when said rear shell portion is in the front position, and which includes a retaining hole formed in said outer barrel wall surface of said larger-diameter wall portion, and extending in a radial direction through said inner barrel wall surface, and an engaging peg disposed to extend in the radial direction, and engageable in said retaining hole to establish an interengagement between said larger-diameter wall portion and said rear shell portion such that movement of said rear shell portion at the front position is arrested; an actuator operable externally and disposed to enable said engaging peg to be disengaged from said retaining hole so as to permit the axial movement of said needle hub to the rear position; a catheter hub including a sleeve portion which is detachably sleeved on said smaller-diameter wall portion and which defines a duct along the axis, and a tip portion which is opposite to said sleeve portion along the axis, and which defines a through hole that is communicated with said duct along the axis and that permits extension of said front segment therethrough; and a tubular catheter having a proximate segment which is inserted into said through hole and which extends along the axis to be fluidly communicated with said duct, and a distal segment which extends from said proximate segment along the axis to extend forwardly of said tip portion so as to surround and sheathe said front segment of said needle cannula while permitting said tip end to project forwardly of said distal segment when said needle cannula is placed in the position of use. 2. The intravenous catheter introducing device of claim 1, wherein said needle hub further includes an intermediate portion which interconnects said front holding portion and said rear shell portion to communicate said needle cannula with said flashback chamber and which is light transmissible to permit viewing of blood flowing therethrough. 3. The intravenous catheter introducing device of claim 2, wherein said needle hub further includes an air-permeable member which is in engagement with said rear shell portion so as to close said flashback chamber. 4. The intravenous catheter introducing device of claim 3, wherein said air-permeable member is made from a porous filter material. 5. The intravenous catheter introducing device of claim 1, wherein said rear larger-diameter wall portion has an elongated guideway extending from said outer barrel wall surface through said inner barrel wall surface in the radial direction, and elongated from said retaining hole rearwardly and in the longitudinal direction to terminate at a rear retaining end, said engaging peg being disposed on and extending radially from said rear shell portion to terminate at a shifted end which extends radially and outwardly of said outer barrel wall surface, and being slidable along said elongated guideway from said retaining hole to said rear retaining end when said rear shell portion of said needle hub slides from the front position to the rear position, said actuator being connected to said shifted end of said engaging peg, and being disposed outwardly of and being slidable relative to said outer barrel wall surface. 6. The intravenous catheter introducing device of claim 5, wherein said elongated guideway has front and rear constricted regions which are formed immediately behind said retaining hole and immediately in front of said rear retaining end, respectively, such that once said engaging peg is forced through one of said front and rear constricted regions, movement of said engaging peg is arrested by virtue of a snap-fit in a corresponding one of said retaining hole and said rear retaining end so as to place said needle hub in a corresponding one of the front and rear positions. 7. The intravenous catheter introducing device of claim 6, wherein said rear larger-diameter wall portion further has a split which extends from said rear retaining end of said elongated guideway to said rear open end. 8. The intravenous catheter introducing device of claim 5, wherein said retaining hole includes a proximate connecting end and a distal retaining end which are opposite to each other in a transverse direction relative to the longitudinal direction and which are proximate to and distal from said elongated guideway, respectively, such that said engaging peg is engaged in said distal retaining end to arrest movement of said rear shell portion of said needle hub at the front position, and such that said actuator is operated to move said engaging peg from said distal retaining end to said proximate connecting end so as to permit slidable movement of said engaging peg along said elongated guideway. 9-14. (canceled) 15. An intravenous catheter introducing device comprising: a barrel having front and rear open ends opposite to each other in a longitudinal direction, and a surrounding barrel wall which interconnects and which is interposed between said front and rear open ends, said surrounding barrel wall including a front smaller-diameter wall portion and a rear larger-diameter wall portion which are opposite to each other in the longitudinal direction and which are proximate to said front and rear open ends, respectively, said surrounding barrel wall having an inner barrel wall surface which surrounds an axis in the longitudinal direction and which confines a passage that is communicated with said front and rear open ends, and an outer barrel wall surface opposite to said inner barrel wall surface in radial directions relative to the axis; a needle cannula having a front segment terminating at a tip end, and a rear connecting end opposite to said front segment along the axis; a needle hub including a front holding portion and a rear shell portion disposed opposite to each other along the axis, said rear shell portion being inserted into said passage from said rear open end, and being slidable relative to said surrounding barrel wall along the axis between front and rear positions to be proximate to said front open end and said rear open end, respectively, said front holding portion holding said rear connecting end of said needle cannula such that when said rear shell portion is in the front position, said needle cannula is placed in a position of use, where said front segment extends forwardly of said front open end for ready use, and when said rear shell portion is in the rear position, said needle cannula is placed in a disposal position, where said front segment retreats into said passage, said rear shell portion surrounding the axis and defining a flashback chamber which is fluidly communicated with said needle cannula; a releasably retaining member which is disposed to arrest axial movement of said needle hub relative to said barrel when said rear shell portion is in the front position, and which includes a retaining hole formed in said outer barrel wall surface of said larger-diameter wall portion, and extending in a radial direction through said inner barrel wall surface, and an engaging peg disposed to extend in the radial direction, and engageable in said retaining hole to establish an interengagement between said larger-diameter wall portion and said rear shell portion such that movement of said rear shell portion at the front position is arrested; an actuator operable externally and disposed to enable said engaging peg to be disengaged from said retaining hole so as to permit the axial movement of said needle hub to the rear position, said actuator including a triggering member which is pivotally mounted on said outer barrel wall surface at a fulcrum point, and which includes a weight end that is formed integrally with said engaging peg, and that is disposed rearwardly of said rear shell portion so as to bring said engaging peg to abut against said rear shell portion when said needle cannula is in the position of use, and a power end disposed at an opposite side of said weight end relative to said fulcrum point so as to be actuated to move said engaging peg in the radial direction to withdraw said engaging peg from said passage, a biasing member which is disposed between said rear shell portion and said inner barrel wall surface to bias said needle hub toward the rear position; a catheter hub including a sleeve portion which is detachably sleeved relative to said front holding portion of said needle hub and which defines a duct along the axis, and a tip portion which is opposite to said sleeve portion along the axis, and which defines a through hole that is communicated with said duct along the axis and that permits extension of said front segment therethrough; and a tubular catheter having a proximate segment which is inserted into said through hole and which extends along the axis to be fluidly communicated with said duct, and a distal segment which extends from said proximate segment along the axis to extend forwardly of said tip portion so as to surround and sheathe said front segment of said needle cannula while permitting said tip end to project forwardly of said distal segment when said needle cannula is placed in the position of use. 16. An intravenous catheter introducing device comprising: a barrel having front and rear open ends opposite to each other in a longitudinal direction, and a surrounding barrel wall which interconnects and which is interposed between said front and rear open ends, said surrounding barrel wall including a front smaller-diameter wall portion and a rear larger-diameter wall portion which are opposite to each other in the longitudinal direction and which are proximate to said front and rear open ends, respectively, said surrounding barrel wall having an inner barrel wall surface which surrounds an axis in the longitudinal direction and which confines a passage that is communicated with said front and rear open ends, and an outer barrel wall surface opposite to said inner barrel wall surface in radial directions relative to the axis; a needle cannula having a front segment terminating at a tip end, and a rear connecting end opposite to said front segment along the axis; a needle hub including a front holding portion and a rear shell portion disposed opposite to and separated from each other along the axis, said rear shell portion being inserted into said passage from said rear open end, and being slidable relative to said surrounding barrel wall along the axis between front and rear positions to be proximate to said front open end and said rear open end, respectively, said front holding portion holding said rear connecting end of said needle cannula such that when said rear shell portion is in the front position, said needle cannula is placed in a position of use, where said front segment extends forwardly of said front open end for ready use, and when said rear shell portion is in the rear position, said needle cannula is placed in a disposal position, where said front segment retreats into said passage, said rear shell portion surrounding the axis and defining a flashback chamber which is fluidly communicated with said needle cannula, said needle hub further including an interconnecting portion which is formed integrally with and which extends forwardly from said rear shell portion along the axis and which defines an axial passageway that extends therethrough and that is communicated with said flashback chamber, and a sleeve portion which is integrally formed with and which extends rearwardly from said front holding portion along the axis and which is detachably sleeved on said interconnecting portion from said front open end of said barrel along the axis so as to fluidly communicate said needle cannula with said flashback chamber; a releasably retaining member which is disposed to arrest axial movement of said needle hub relative to said barrel when said rear shell portion is in the front position, and which includes a retaining hole formed in said outer barrel wall surface of said larger-diameter wall portion, and extending in a radial direction through said inner barrel wall surface, and an engaging peg disposed to extend in the radial direction, and engageable in said retaining hole to establish an interengagement between said larger-diameter wall portion and said rear shell portion such that movement of said rear shell portion at the front position is arrested; an actuator operable externally and disposed to enable said engaging peg to be disengaged from said retaining hole so as to permit the axial movement of said needle hub to the rear position; a catheter hub including a sleeve portion which is detachably sleeved on said front holding portion of said needle hub and which defines a duct along the axis, and a tip portion which is opposite to said sleeve portion along the axis, and which defines a through hole that is communicated with said duct along the axis and that permits extension of said front segment therethrough; and a tubular catheter having a proximate segment which is inserted into said through hole and which extends along the axis to be fluidly communicated with said duct, and a distal segment which extends from said proximate segment along the axis to extend forwardly of said tip portion so as to surround and sheathe said front segment of said needle cannula while permitting said tip end to project forwardly of said distal segment when said needle cannula is placed in the position of use. 17. The intravenous catheter introducing device of claim 16, further comprising a biasing member which is interposed between said rear shell portion and said inner barrel wall surface, and which is disposed to bias said needle hub toward the rear position. | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and device for measuring fluctuations in the cross sectional area of a bundle of hair for the purpose of documenting the clinical course of medical hair loss disorders and the effectiveness of hair growth treatments and/or for the purpose of indirectly calculating the severity of balding disorders or efficacy of hair growth treatment as evidenced by a decrease or increase in hair population and/or hair shaft diameter. 2. Description of the Related Art Heretofore, a hair volume-measuring device used for measure of hair damage was disclosed in the Kabacoff et al. U.S. Pat. No. 4,665,741. Hair shedding is a condition characterized by loss of hairs of normal-sized diameters. It is one of the two major categories of hair loss. Shedding is diffusely distributed over the scalp and may be the sign of several medical abnormalities and toxicities. It may physiologically follow high fever, cessation of birth control pills, or childbirth. Shedding is characterized by the appearance of skin on the scalp where hair was once present. Shedding may be quantified by measuring the density of hairs present in an area of one-centimeter square of scalp. Hair density usually is measured by closely cutting the scalp hair (about 2 mm long in an area 5 mm×5 mm) and then counting the remaining cut hairs present on the scalp and multiplying that value times 4. The hair density of normal individuals in the absence of shedding ranges between 120 to 200 hairs per sq cm of scalp. Hair thinning is a condition characterized by the gradual miniaturization of individual scalp hairs. It is the second major category of hair loss. The appearance of hair loss is the result of decreasing diameters resulting in the eventual absence of hairs. Thinning (like shedding) also is characterized by the appearance of skin on the scalp where hair was once present. Thinning affects an estimated 75% of men and 10% of women. Unlike shedding, it is not diffuse in its distribution over the entire scalp surface, but almost always appears in a pattern, with hair loss on the top of the scalp. Thinning characteristically spares the posterior and sides of the lower scalp, creating a familiar horse-shaped fringe that persists in spite of the most advanced cases. Thinning occurs in healthy individuals and is referred to as balding, pattern balding, male or female pattern alopecia, androgenctic alopecia, male or female pattern balding. It is considered normal in 75% of men. And, although it may occur in healthy women, it may indicate an endocrine abnormality in a small group of women. Early pattern balding is difficult to recognize and difficult to quantify. Simple density measurements (as performed in shedding) are of little value because there is a mixed population of both normal-sized and miniaturized hairs. When density counts are performed, a normal and miniaturized hair would each be counted as one hair. Therefore, in order to detect and quantify thinning in a meaningful manner, the actual hair mass (the collective cross sections of hair from a predetermined area of scalp) must be measured. This alone would reflect the density of hairs and the array of mixed diameters that are present. In order to quantify pattern and diffuse hair loss, scientists have commonly used three basic methods: 1. Hair density count 2. Clinical photography 3. Hair weight. Quantification of hair loss by measuring the collective cross sections in a pre-determined area of scalp has not been reported in the scientific literature nor disclosed in prior U.S. Patents. The three commonly used methods are described in more detail below: Density count: The density of an area of scalp is compared to the known normal range of values, which is 120 to 200 hairs per sq cm. To determine the percent loss of density for a single individual, the density on the top part of the scalp (the area of loss) may be compared to the density on the lower back and sides (the normal and permanent hair zone). The percent hair loss is calculated by dividing the hair count in the hair loss area by the hair count in the permanent zone. This method is quite imprecise in conditions of thinning, because it measures only the number of hairs and makes no allowance for their variations in diameter. The method is used however because it is a bit more precise than clinical photography. It requires cutting off hair and direct scalp exam with a hand lens or video microscope. Clinical photography: Photography is performed comparing the patient's hair loss area to the permanent zone. It may also compare the patient's hair loss zone to a picture of the same zone of a patient with no hair loss, or of a prior or subsequent state of loss in the same patient. In this manner, the growth or loss is grossly quantified by visual observation alone. No insight is gained into whether or not the hair loss is the result of thinning or shedding. Photography is quite imprecise and obscured by various hairstyles and hair lengths. It is however the most common form of hair loss documentation because it is rapid, requires not special training and is easily archived. It does not require the cutting of hair, but does require standard photo equipment lighting, positioning of hair, and standardized hair length, to yield any kind of comparable data. Hair weight: A small area of hair (usually 5 mm×5 mm) is shaved from a balding area. The patient returns in 30 days and the newly grown hair is cut and weighed. The value is compared to a subsequent similar assay of the same area. In cases of pattern loss, the procedure may be performed in the permanent zone (lower posterior and lateral horseshoe shaped zone) and compared to the value in the thinning zone. The percent hair loss may be calculated by dividing the hair weight in the thinning area by the hair weight in the permanent zone. Hair weight is a very precise method of measuring hair loss because it considers both the number of hairs and their diameters and the hair length in its calculation. Its disadvantage is that the sample size represents a relatively small sample of the scalp surface, and because it measures hair length as well, it may not be as meaningful as thought. Furthermore it is a very tedious process and impractical to perform in a clinical setting. It also requires cutting off hair. It is used primarily by commercial laboratories to measure the effectiveness of hair-growing preparations i.e. finasteride, dutasteride, and minoxidil. BRIEF SUMMARY OF THE INVENTION According to the present invention there is provided a method and device for measuring fluctuations in the cross sectional area of a section of hair as it relates to the quantification and clinical course of medical hair loss disorders or the effectiveness or progress of hair loss treatment. The method and device are used for determining the cumulative cross-section of hairs within a pre-measured area. The method and device uses a much larger sample of scalp surface than the hair weight method, hair count method, and hair cutting is not required. The length of the hair is not considered a factor in the evaluation because of wide variations of individual styling would make it impossible, and clinically irrelevant. The method of the present invention is easy to perform in a non-laboratory setting and employs a new hand-held device. The method and device allow physicians and hair care professionals to track and document the status of patients, suffering from scalp hair thinning or shedding, at any time in the course of their evaluation or treatment. The method and device may be used to quantitatively evaluate the effectiveness of hair growing preparations and drugs and quantify the severity and clinical course of other medical hair loss disorders. In practicing the method of the present invention, a predetermined area of hair-bearing skin or scalp is isolated by any of several means. Typically a 2×2 cm of scalp hair is manually isolated using a comb or combing element and fixed in place using 1×3″ gummed papers printed with a centimeter scale which are aligned and overlapped in the configuration of a 2×2 cm square. Alternatively, a 2×2 cm area may be isolated by using any device that demarcates the periphery of the area, such as with a ruler and washable ink, marking pen, and/or using a simple comb-like device that is 2 cm. in length, which simultaneously bundles the hair and demarcates the perimeter of the area. The bundle is snared by a lightweight spring-loaded hook-like (“J” shaped) arm which is drawn into a body of the device of the present invention. The device comprises a hair-trapping element including a “J” shaped end that extends through a boss and has a hair-receiving slot. The device further includes an anvil on an end surface of the boss positioned adjacent the slot whereby relative movement between the “J” shaped end and the anvil compresses the hair received in the slot. A heavyweight compression spring is provided in the device which bears against the boss. Alternatively the device can have an anvil that moves into a stationary slot. The bundle is captured in the slot and automatically immobilized against the anvil on the boss. Preferably, the slot is 1 mm wide and 12 mm high and relative movement between the anvil and the slot measures the height of the hair. By engaging the heavy compression spring, the load on the column of trapped hair may be precisely maintained and thereby kept constant in repeated measurements. This is important because the hair bundle is quite compressible. The mm height of the hair column is displayed on an LED window of an integrated micrometer head that causes relative movement between the anvil and the slot. If a mechanical height measuring gauge is incorporated in the design of the device, it is displayed on the face of an analog dial. If an electronic height measuring gauge is incorporated into the device, the height is displayed on an LED window. The height of hair in the trapping hair-receiving slot is expressed as an arbitrary value that shall be called the hair mass, the hair mass index, the cross-sectional index, the cumulative cross-sectional index, or the combined cross-sectional index. The method is performed in the hair thinning area and the permanent hair growth area of the scalp. The index value of the thinning area is divided by the index value of the permanent area. The percent loss of hair mass in the thinning area is thus derived. It is believed that the method and device of the present invention may have profound medical significance for the following reason: It is a known medical fact that an individual must lose half of the hair in an area of the scalp, before it is obvious to the casual observer that any hair has been lost. This can also be demonstrated by the casual observers inability to tell the difference between a toupee with 200 hairs per sq cm and a toupee with 100 hairs per sq cm. This observation however translates to the following: By the time an individual realizes that he is “losing hair” he has already lost half of his hair! The device of the present invention enables hair professionals and physicians to measure the hair mass in the pre-balding normal-looking areas of the scalp and compare these values to the hair mass value in the permanent zone. In this way one can detect whether or not there is hair loss years before it is visually obvious to the patient or his physician. The patient is alerted to the early hair loss and may enjoy the advantages of starting therapy before the loss has significantly advanced. The method and device may also be used to track and quantify the progressive hair loss of individuals with untreated balding, or track and quantify the therapeutic response of hair to drugs and devices that allegedly grow hair. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 is a top view of a scalp showing a section or bundle of hair that is combed from a delineated section of scalp with a combing element and shows one side of the section of scalp being delineated by a gummed label. FIG. 2 is a top view of a scalp showing a section or bundle of hair that is combed from a delineated section of scalp and shows two sides of the section of scalp being delineated by gummed labels. FIG. 3 is a top view of a scalp showing a section or bundle of hair that is combed from a delineated section of scalp and shows three sides of the section of scalp being delineated by gummed labels. FIG. 4 is a top view of a scalp showing a section or bundle of hair that is combed from a delineated section of scalp and shows four sides of the section of scalp being delineated by gummed labels. FIG. 5 is a plan view of one combing element. FIG. 6 is a top plan view of the scalp shown in FIG. 4 and a device constructed according to the teachings of the present invention for measuring the cross-sectional area of the bundle of hair. FIG. 7 is a top plan view of a scalp shown in FIG. 6 with a “J” shaped end of the device move toward a boss on the body of the device to measure the cross-sectional area of the bundle of hair positioned in a slot of the “J” shaped end. FIG. 8 is a fragmentary enlarged view of the hair trapped in the slot of the “J” shaped end. FIG. 9 is a cross-sectional view of the “J” shaped end taken along line 9-9 of FIG. 8. FIG. 10 is a cross-sectional view of a boss extending from the body of the device and in which the “J” shaped end is received. FIG. 11 is a plan view of the device without a bundle of hair in the slot of the “J” shaped end, shows the “J” shaped end moved over the boss, and is broken away to show a heavy compression spring in the body of the device. DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1 there is illustrated therein a combed bundle or section of hair 10 from a scalp 12, that has been combed with a comb or combing element 14. The bundle 10 of hair is delineated from a predetermined area of the scalp 12 by a gummed label 16, without cutting the bundle 10 of hair. As shown in FIGS. 2-4, sequentially the delineated area of the scalp is fixed by gummed labels 18, 20 and 22. Each gummed label has a centimeter scale printed thereon so that the predetermined area, e.g., 2 square centimeters, can be measured and segregated by the gummed labels 16, 18, 20 and 22 from the rest of the hair on the scalp. The gummed labels 16, 18, 20 and 22 are printed with lines at intervals 2 cm apart scale. The color-coded lines are aligned with the edge of the preceding label and overlapped in a 4 step sequential fashion to create an isolated field of uncut hair that is 2 cm square. Preferably, a 2×2 cm of scalp hair is manually isolated by combing the hair away from the designated square of hair-bearing scalp skin. This is done in a sequential fashion as described above. Care is taken to maintain a straight line at 90 degrees from the previous passage of the combing element 14. The combing element 14 is shown in FIG. 5 and has a predetermined tine area 26, e.g., 2 cm. long, with tines 28 and an upwardly sloping top edge 29 extending to a handle 30. A device 32 is provided, as shown in FIG. 6 for measuring the mass of hair in a bundle 10 from the 2 sq cm area of a hair bearing skin or scalp and compares that hair mass to the hair mass per sq. cm. in a permanent (normal) zone on the scalp. The device 32 is an electronic caliper 34 having a body 36 with an electronic display 38 and a scale, gauge or analog display 40 for indicating the height or mass of hair in the hair bundle 10. The device 32 includes a piston or plunger 42 that extends through the body 36 and has a collar 43 thereon below a knob 44 at an outer end 46 of the plunger 42. A light weight return spring 48 (FIG. 7) bears against the collar 43 to urge the knob 44 away from an upper end 49 of the body 36 to push the plunger 42 upwardly. As shown a collar 50 between the spring 48 and the upper end 49 of the body of the body 36 is provided and has a reduced in diameter portion 51 that extends into the body 36. It will be understood that the scale, gauge or analog display 40 moves with the plunger 42. Also, of course, the amount of movement of the plunger will be shown on the display 38. The other end 52 of the plunger 42 has a “J” shape defined by a main leg 53 and a hook leg 54 with a slot 56 therebetween. The slot 56 can be 1 mm wide and 12 mm high. The main leg 52 extends through a through bore 58 (FIG. 9) in a boss 60 at a lower end 61 of the body 36. As shown in FIG. 11 a heavy compression spring 62 in the body 36 bears against a lower end 63 of the reduced in diameter portion 51 of the collar 50. A wall 64 of the boss 60 between the bore 58 and an outer surface 63 of the boss 60 is slidably received in the slot 56 upon relative movement between the boss 60 and the “J” shaped end 52. The bundle of hair 10 is placed in the slot 56 and the knob 44 is screwed down on the plunger 42 and moves the reduced in diameter portion 51 of the collar 50 into the body 36 to compress the bundle of hair 10 between a bottom 66 of the slot 56 and an end surface 68 of the wall 54 (FIG. 9) with a predetermined compression established by the spring constant of the heavy spring 62 acting on the plunger 42. The end surface 68 defines an anvil 68 against which the bundle 10 of hair is compressed. In this way the device 32 defines a measuring device comprising the hair-holding slot 56, the “J” shaped end of the spring-loaded plunger 42 and the anvil 68. The bundle or column 10 of hair is placed into the slot 66 and compressed against the anvil 68 in order to measure its height of the column or bundle 10 of hair. The anvil 68 and plunger are designed in a manner that always applies the same pressure to the column or bundle 10 of trapped hair. (This is accomplished with the heavy compression spring 62 bearing against the reduced in diameter portion of the collar 51) This is important because the hair bundle 10 is quite compressible. The mm height of the hair bundle or column 10 is read off a window on the electronic display 38 and/or off of the scale gauge or analog display 40. This arbitrary value shall be called the hair loss index or the density-diameter index. The procedure is performed in the balding area and the permanent area. The value for the balding area is divided by the value for the permanent area. The percent loss of hair mass in the balding is thus derived. Oddly, in pattern balding (Androgenetic alopecia), the back and sides of the scalp are immune to the thinning process which doctors call miniaturization. So that on a balding scalp, the permanent horseshoe shaped fringe is populated with normal sized hairs (70 microns) with a normal density of 120-200 hairs per square cm. On the top of the scalp, in the areas of hair loss, the population of hairs ranges in size from 70 microns to 15 microns in diameter with a wide range of hairs per square cm. The cumulative number of hairs per sq cm of scalp times their cumulative diameters equals a value that is best described as the hair mass. When the hair mass value of the balding zone is divided by the hair mass value of the normal permanent zone, the percent loss of hair mass in the balding area is derived. When the hair mass value in an area of loss is compared with a subsequent measurement of the same area at a time in the future, the percent hair loss or growth may be derived. This information is very important to those who care for patients with hair loss, and those who develop drugs or devices that promote hair growth. Again it must be emphasized that although the length of the hair does contribute to the total visual mass of hair, it is not considered because it varies with the cut length of the hair (styling) which has no relevance to intended application of this patent. From the foregoing description, it will be understood that the method and device of the present invention have a number of advantages, some of which have been described above and others of which are inherent in the method and device of the present invention. Also modifications can be made to the method and device of the present invention without departing from the teachings of the present invention. For example, a mark can be placed on the body 36 and another mark placed on the plunger 42 and a separate caliper can be used to measure the distance between the marks for determining the height of hair compressed in the slot 56. The heavy spring 62 can be omitted and the knob 44 can be tightened with a torque wrench to place a predetermined amount of compression on the bundle 10 of hair. A simple protrusion with an anvil at the end can used in place of the boss 60 and received in the slot 56. A simpler device can be provided including a body with the slot 56 therein and a piston having the anvil 68 at one end can be provided and positioned to be received in the slot 56. The body can be moved against the piston or the piston can be moved in and out of the slot 56. The body and piston can be provided with a return spring, like spring 48, for holding the anvil 68 in the slot 56 until the spring is compressed to move the anvil 68 out of the slot 56. If desired, side arms can be provided on the body, much like on a syringe, to facilitate gripping of the body while the piston or plunger is reciprocated or the knob 44 is rotated. The non-isolated hair can be held down by other means, such as a ruler or hair clips instead of with gummed labels. Further, the caliper can be mechanical or electrical electronic, can be attached to the body or plunger or can be separate from the device 32. Accordingly, the scope of the invention is only to be limited as necessitated by the accompanying claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a method and device for measuring fluctuations in the cross sectional area of a bundle of hair for the purpose of documenting the clinical course of medical hair loss disorders and the effectiveness of hair growth treatments and/or for the purpose of indirectly calculating the severity of balding disorders or efficacy of hair growth treatment as evidenced by a decrease or increase in hair population and/or hair shaft diameter. 2. Description of the Related Art Heretofore, a hair volume-measuring device used for measure of hair damage was disclosed in the Kabacoff et al. U.S. Pat. No. 4,665,741. Hair shedding is a condition characterized by loss of hairs of normal-sized diameters. It is one of the two major categories of hair loss. Shedding is diffusely distributed over the scalp and may be the sign of several medical abnormalities and toxicities. It may physiologically follow high fever, cessation of birth control pills, or childbirth. Shedding is characterized by the appearance of skin on the scalp where hair was once present. Shedding may be quantified by measuring the density of hairs present in an area of one-centimeter square of scalp. Hair density usually is measured by closely cutting the scalp hair (about 2 mm long in an area 5 mm×5 mm) and then counting the remaining cut hairs present on the scalp and multiplying that value times 4 . The hair density of normal individuals in the absence of shedding ranges between 120 to 200 hairs per sq cm of scalp. Hair thinning is a condition characterized by the gradual miniaturization of individual scalp hairs. It is the second major category of hair loss. The appearance of hair loss is the result of decreasing diameters resulting in the eventual absence of hairs. Thinning (like shedding) also is characterized by the appearance of skin on the scalp where hair was once present. Thinning affects an estimated 75% of men and 10% of women. Unlike shedding, it is not diffuse in its distribution over the entire scalp surface, but almost always appears in a pattern, with hair loss on the top of the scalp. Thinning characteristically spares the posterior and sides of the lower scalp, creating a familiar horse-shaped fringe that persists in spite of the most advanced cases. Thinning occurs in healthy individuals and is referred to as balding, pattern balding, male or female pattern alopecia, androgenctic alopecia, male or female pattern balding. It is considered normal in 75% of men. And, although it may occur in healthy women, it may indicate an endocrine abnormality in a small group of women. Early pattern balding is difficult to recognize and difficult to quantify. Simple density measurements (as performed in shedding) are of little value because there is a mixed population of both normal-sized and miniaturized hairs. When density counts are performed, a normal and miniaturized hair would each be counted as one hair. Therefore, in order to detect and quantify thinning in a meaningful manner, the actual hair mass (the collective cross sections of hair from a predetermined area of scalp) must be measured. This alone would reflect the density of hairs and the array of mixed diameters that are present. In order to quantify pattern and diffuse hair loss, scientists have commonly used three basic methods: 1. Hair density count 2. Clinical photography 3. Hair weight. Quantification of hair loss by measuring the collective cross sections in a pre-determined area of scalp has not been reported in the scientific literature nor disclosed in prior U.S. Patents. The three commonly used methods are described in more detail below: Density count: The density of an area of scalp is compared to the known normal range of values, which is 120 to 200 hairs per sq cm. To determine the percent loss of density for a single individual, the density on the top part of the scalp (the area of loss) may be compared to the density on the lower back and sides (the normal and permanent hair zone). The percent hair loss is calculated by dividing the hair count in the hair loss area by the hair count in the permanent zone. This method is quite imprecise in conditions of thinning, because it measures only the number of hairs and makes no allowance for their variations in diameter. The method is used however because it is a bit more precise than clinical photography. It requires cutting off hair and direct scalp exam with a hand lens or video microscope. Clinical photography: Photography is performed comparing the patient's hair loss area to the permanent zone. It may also compare the patient's hair loss zone to a picture of the same zone of a patient with no hair loss, or of a prior or subsequent state of loss in the same patient. In this manner, the growth or loss is grossly quantified by visual observation alone. No insight is gained into whether or not the hair loss is the result of thinning or shedding. Photography is quite imprecise and obscured by various hairstyles and hair lengths. It is however the most common form of hair loss documentation because it is rapid, requires not special training and is easily archived. It does not require the cutting of hair, but does require standard photo equipment lighting, positioning of hair, and standardized hair length, to yield any kind of comparable data. Hair weight: A small area of hair (usually 5 mm×5 mm) is shaved from a balding area. The patient returns in 30 days and the newly grown hair is cut and weighed. The value is compared to a subsequent similar assay of the same area. In cases of pattern loss, the procedure may be performed in the permanent zone (lower posterior and lateral horseshoe shaped zone) and compared to the value in the thinning zone. The percent hair loss may be calculated by dividing the hair weight in the thinning area by the hair weight in the permanent zone. Hair weight is a very precise method of measuring hair loss because it considers both the number of hairs and their diameters and the hair length in its calculation. Its disadvantage is that the sample size represents a relatively small sample of the scalp surface, and because it measures hair length as well, it may not be as meaningful as thought. Furthermore it is a very tedious process and impractical to perform in a clinical setting. It also requires cutting off hair. It is used primarily by commercial laboratories to measure the effectiveness of hair-growing preparations i.e. finasteride, dutasteride, and minoxidil. | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>According to the present invention there is provided a method and device for measuring fluctuations in the cross sectional area of a section of hair as it relates to the quantification and clinical course of medical hair loss disorders or the effectiveness or progress of hair loss treatment. The method and device are used for determining the cumulative cross-section of hairs within a pre-measured area. The method and device uses a much larger sample of scalp surface than the hair weight method, hair count method, and hair cutting is not required. The length of the hair is not considered a factor in the evaluation because of wide variations of individual styling would make it impossible, and clinically irrelevant. The method of the present invention is easy to perform in a non-laboratory setting and employs a new hand-held device. The method and device allow physicians and hair care professionals to track and document the status of patients, suffering from scalp hair thinning or shedding, at any time in the course of their evaluation or treatment. The method and device may be used to quantitatively evaluate the effectiveness of hair growing preparations and drugs and quantify the severity and clinical course of other medical hair loss disorders. In practicing the method of the present invention, a predetermined area of hair-bearing skin or scalp is isolated by any of several means. Typically a 2×2 cm of scalp hair is manually isolated using a comb or combing element and fixed in place using 1×3″ gummed papers printed with a centimeter scale which are aligned and overlapped in the configuration of a 2×2 cm square. Alternatively, a 2×2 cm area may be isolated by using any device that demarcates the periphery of the area, such as with a ruler and washable ink, marking pen, and/or using a simple comb-like device that is 2 cm. in length, which simultaneously bundles the hair and demarcates the perimeter of the area. The bundle is snared by a lightweight spring-loaded hook-like (“J” shaped) arm which is drawn into a body of the device of the present invention. The device comprises a hair-trapping element including a “J” shaped end that extends through a boss and has a hair-receiving slot. The device further includes an anvil on an end surface of the boss positioned adjacent the slot whereby relative movement between the “J” shaped end and the anvil compresses the hair received in the slot. A heavyweight compression spring is provided in the device which bears against the boss. Alternatively the device can have an anvil that moves into a stationary slot. The bundle is captured in the slot and automatically immobilized against the anvil on the boss. Preferably, the slot is 1 mm wide and 12 mm high and relative movement between the anvil and the slot measures the height of the hair. By engaging the heavy compression spring, the load on the column of trapped hair may be precisely maintained and thereby kept constant in repeated measurements. This is important because the hair bundle is quite compressible. The mm height of the hair column is displayed on an LED window of an integrated micrometer head that causes relative movement between the anvil and the slot. If a mechanical height measuring gauge is incorporated in the design of the device, it is displayed on the face of an analog dial. If an electronic height measuring gauge is incorporated into the device, the height is displayed on an LED window. The height of hair in the trapping hair-receiving slot is expressed as an arbitrary value that shall be called the hair mass, the hair mass index, the cross-sectional index, the cumulative cross-sectional index, or the combined cross-sectional index. The method is performed in the hair thinning area and the permanent hair growth area of the scalp. The index value of the thinning area is divided by the index value of the permanent area. The percent loss of hair mass in the thinning area is thus derived. It is believed that the method and device of the present invention may have profound medical significance for the following reason: It is a known medical fact that an individual must lose half of the hair in an area of the scalp, before it is obvious to the casual observer that any hair has been lost. This can also be demonstrated by the casual observers inability to tell the difference between a toupee with 200 hairs per sq cm and a toupee with 100 hairs per sq cm. This observation however translates to the following: By the time an individual realizes that he is “losing hair” he has already lost half of his hair! The device of the present invention enables hair professionals and physicians to measure the hair mass in the pre-balding normal-looking areas of the scalp and compare these values to the hair mass value in the permanent zone. In this way one can detect whether or not there is hair loss years before it is visually obvious to the patient or his physician. The patient is alerted to the early hair loss and may enjoy the advantages of starting therapy before the loss has significantly advanced. The method and device may also be used to track and quantify the progressive hair loss of individuals with untreated balding, or track and quantify the therapeutic response of hair to drugs and devices that allegedly grow hair. | 20040416 | 20060207 | 20060112 | 65279.0 | A61B5103 | 0 | COURSON, TANIA C | METHOD AND DEVICE FOR MEASURING FLUCTUATIONS IN THE CROSS-SECTIONAL AREA OF HAIR IN A PRE-DETERMINED SCALP AREA | SMALL | 0 | ACCEPTED | A61B | 2,004 |
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10,827,097 | ACCEPTED | Method and apparatus for ink jet printing on rigid panels | Ink jet printing is provided onto rigid panels such as foamboard and contoured material using ultraviolet (UV) light curable ink, which is first at least partially cured with UV light and then may be subjected to heating. Printhead-to-panel spacing is controllable to maintain a predetermined constant distance from the printing element to the surface of the panel where the ink is to be applied. Each of a plurality of printheads may be independently moveable to control the spacing of the printheads from the substrate surface. Sensors on the printhead carriage measure the shape, or vertical position of, the printhead's distance from the printhead carriage to the surface of the substrate being printed. The position or focal length of the UV light curing head may be varied to maintain focus of the UV light on the ink on a contoured surface of the substrate. UV curing heads may be located on the printhead carriage, one on each side of the printheads, and activated alternately as the carriage reciprocates, to spot cure and freeze the dots of ink immediately after being deposited on the substrate. Cold UV sources may be used to prevent heat deformation of flat or contoured substrates during printing, thereby making spot curing on heat-sensitive substrates such as foamboard possible. | 1. A method of ink jet printing with UV curable ink on a substrate that may be formed of a heat sensitive rigid or other material, the method comprising: moving a printhead carriage having an ink jet printhead thereon approximately parallel to a substrate; jetting ink from the heads across the predetermined distance onto the surface of a substrate; providing at least one cold UV curing assembly on the carriage oriented to direct UV energy onto the surface of the substrate sufficiently close to where ink is being jetted onto the surface so as to freeze dots of the jetted ink on the surface; and the cold UV assembly being effective to impinge sufficient UV light on the ink to substantially cure the ink while without impinging radiation of other wavelengths that would heat the substrate so as to deform it. 2. The method of claim 1 further comprising: adjusting the distance from the printheads to the substrate to position the head at a predetermined distance from the surface of the substrate on which ink is jetted from the heads. 3. The method of claim 1 further comprising: the exposing of the ink includes adjusting the distance of the UV light from a light source to focus the UV light onto the surface that bears the jetted ink. 4. The method of claim 3 wherein: the exposing of the ink includes adjusting the focal length from a source of the UV light on the surface that bears the jetted ink to maintain the focus of UV light thereon as distance from the source to the surface varies. 5. The method of claim 1 wherein: the ink is UV curable ink; the method further comprises at least partially curing the ink jetted onto the surface by exposing the jetted ink to ultraviolet light and then heating the surface having the at least partially cured ink thereon to reduce the content of unpolymerized monomers of the ink on the substrate. 6. The method of claim 5 wherein the heating includes flowing heated air onto the surface of the substrate having the at least partially cured UV light cured ink thereon to remove uncured components of the ink from the substrate. 7. The method of claim 1 further comprising: sensing the position of the surface of the substrate relative to the carriage; and adjusting the distance from the printhead to the plane of the substrate in response to said sensing. 8. The method of claim 7 wherein: the sensing of the positions is carried out while moving the printhead carriage; and the adjusting includes varying the position of the printhead relative to the plane of the substrate as the printhead carriage moves so as to maintain the predetermined distance of each of the printheads from the surface of the substrate in response to the sensed position. 9. An apparatus for printing on three-dimensional surfaces of substrates comprising: a substrate support defining a substrate supporting plane; a printhead track extending parallel to the plane having a printhead carriage moveable thereon; at least one ink jet printhead on the carriage; at least one UV curing head on the carriage sufficiently close to the ink jet printhead to freeze dots of ink in position on the substrate when jetted thereon from the printhead; the UV curing head being configured to emit sufficient UV energy to cure the ink jetted onto the substrate without heating and thermally deforming the substrate when formed of a heat deformable material. 10. The apparatus of claim 9 further comprising: a plurality of ink jet printheads each moveably supported on the carriage and directed toward the surface of a substrate when supported by the substrate support; a sensor operable to determine a location on the surface of the substrate; and the printheads being separately and selectively moveable perpendicular to the plane in response to the sensor to a predetermined distance from the determined location on the surface of the substrate; and a controller operable to move and control the printheads to print on the substrate by jetting ink from the printheads across the predetermined distance and onto the surface of a substrate. 11. The apparatus of claim 10 further comprising: a carriage moveable on the track parallel to the plane of the substrate, the printheads being separately and selectively moveable perpendicular to the plane; at least one UV curing head mounted on the carriage and directed so as to expose ink on the surface of a substrate on the substrate support; and the controller being operable to move the carriage and to operate the UV curing head. 12. The apparatus of claim 11 wherein: the at least one UV curing head includes at least two cold UV curing heads, one positioned on the carriage at each side of the printheads so that one leads the printheads and one trails the printheads as the carriage moves on in either of two opposite directions on the track; and the controller is operable to activate at least the trailing one of the UV curing heads to expose the ink jetted by the printheads on the surface of the substrate in the same pass of the carriage over the surface in which the ink being exposed was jetted. 13. The apparatus of claim 11 wherein: the UV curing head is moveable relative to the plane; and the controller is operable to move the curing head to maintain focus of UV light from the printhead on ink jetted onto the surface of the substrate. 14. The apparatus of claim 11 further comprising: a heating station positioned so as to heat UV light exposed ink on a substrate. 15. The apparatus of claim 14 wherein: the heating station includes a blower oriented to direct heated air onto a substrate on the support. 16. The apparatus of claim 9 wherein: the plurality of ink jet printheads includes a plurality of individually moveable printheads spaced in the direction of movement of the carriage so as to sequentially pass over the same areas of the substrate, each printing one of a set of colors thereon; the printheads being separately and selectively moveable perpendicular to the plane in response to the sensor to maintain a constant distance of travel of ink from each printhead to the surface of the substrate; and a controller operable to control the printheads to sequentially follow the contour of the substrate surface as the carriage moves across the substrate. 17. The apparatus of claim 16 wherein: the plurality of ink jet printheads includes a plurality of sets of individually moveable printheads arranged side-by-side on the carriage perpendicular to the direction of movement of the carriage so that each can maintain a controlled spacing from the substrate where the contour of the substrate varies in the direction perpendicular to the movement of the carriage. 18. The apparatus of claim 9 wherein: the plurality of ink jet printheads includes a plurality of individually moveable printheads arranged side-by-side on the carriage perpendicular to the direction of movement of the carriage so that each can maintain a controlled spacing from the substrate where the contour of the substrate varies in the direction perpendicular to the movement of the carriage. | This application is a continuation of application Ser. No. 09/989,006, filed on Nov. 21, 2001, which is a continuation-in-part of PCT Application No. PCT/US01/27023 filed Aug. 30, 2001, the disclosure of which is hereby expressly incorporated by reference herein. FIELD OF THE INVENTION The present invention relates to printing onto rigid substrates, and to the printing onto textured, contoured or other three-dimensional substrates. The invention is particularly related to the printing onto such substrates as those having textile fabric surfaces or molded objects, rigid panels such as office partitions, automobile interior panels and other contoured objects, and to such printing using ink jet printing techniques. BACKGROUND OF THE INVENTION Applying ink to a substrate by ink jet printing requires a proper spacing between the ink jet nozzles and the surface of the substrate to which the printing is applied. Normally, this spacing must be set to within one or two millimeters to maintain effective printing by an ink jet process. If the distance from the nozzles to the surface being printed is too great, deviations from ideal parallel paths of the drops from different nozzles become magnified. Further, the longer the flight path of the drops from the printhead to the substrate, the more dependent the accuracy of the printing becomes on the relative speed between the printhead and the substrate. This dependency limits the rate of change in printhead-to-substrate velocity, including changes in direction. Also, the velocity of the drops moving from the printhead nozzles to the substrate declines with the distance traveled from the nozzles, and the paths of such drops become more greatly affected by air currents and other factors with increased nozzle to substrate distance. Additionally, droplet shape changes the farther the drop moves from the nozzle, which changes the effects of the drop on the substrate. Accordingly, variations in the distance from the printhead to the substrate can cause irregular effects on the printed image. In addition to problems in jetting ink onto contoured surfaces, the curing of UV inks requires delivery of sufficient curing energy to the ink, which is often difficult to achieve where the surface is contoured. Further, some substrates deform, even temporarily, when heated. Deformation caused by heat may be such that, for example, the material returns to its undeformed state when it cools. Nonetheless, even temporary deformation can adversely affect the print quality if it exists when ink is being jetted onto the substrate. Where spot curing of UV inks is employed, which is performed by exposing ink to UV immediately upon its contacting the substrate, UV that is accompanied by heat producing radiation can deform substrates such as foamboard while the ink jets are making single or multiple passes over the deformed print area. For these reasons, ink jet printing has not been successful on contoured materials and other three-dimensional substrates, particularly when printing with UV curable inks. SUMMARY OF THE INVENTION An objective of the present invention is to provide for the ink jet printing onto substrates that tend to deform when heated. A particular objective of the present invention is to maintain desired printhead-to-substrate spacing when jetting ink onto rigid substrates, particularly with UV curable inks. According to the principles of the present invention, printed images are applied to rigid substrates with printing elements that may be moveable relative to the plane of the substrate being printed. In certain embodiments, the invention provides a wide-substrate ink jet printing apparatus with printheads that move toward and away from the plane of a substrate to maintain a fixed distance between the nozzles of the printhead and the surface onto which the ink is being jetted. The variable distance over the plane of the substrate allows a controlled and uniform distance across which the ink is jetted. According to the invention, the printing element may include an ink jet printhead set having a plurality of heads, typically four, each for dispensing one of a set of colors onto the substrate to form a multi-colored image. To maintain the constant distance or to otherwise control the distance, one or more sensors may be provided to measure the distance from the printhead or from the printhead carriage track to the point on the substrate on which ink is to be projected. Such sensors generate reference signals that are fed to a controller that controls a servo motor on the printhead carriage. The printhead may be moveably mounted to the carriage, for example, on a ball screw mechanism, and be moveable toward and away from the plane of the substrate by operation of the servo motor. Each printhead of the set may include four different color printheads that are separately moveable relative to a common printhead carriage, and are each connected to one of a set of four servo motors by which its position relative to the plane of the substrate is capable of control relative to the positions of the other printheads. The printheads of the set may be arranged side-by-side in the transverse direction on the carriage so that one head follows the other across the width of the substrate as the carriage scans transversely across the substrate. Each printhead has, in the preferred embodiment, a plurality of ink jet nozzles thereon for dispensing a given color of ink in a corresponding plurality of dots, for example, 128 in number, that extend in a line transverse to the carriage, which is in a longitudinal direction perpendicular to the scan direction of the carriage. Two laser or optical sensors are provided on the carriage, one on each side of the heads, so that a distance measurement of the surface to the substrate can be taken ahead of the printheads when the heads are scanning in either direction. The controller records the contour of the substrate ahead of the printheads and varies the position of each printhead, toward and away from the substrate plane, as each printhead passes over the points at which the measurements were taken, so that each of the independently moveable heads follows the contour and maintains a fixed distance from the surface being printed. While it is preferred to adjust the position of the printhead or nozzle thereof relative to the substrate which is fixed on a printing machine frame, the substrate surface can alternatively be positioned relative to a printhead that is maintained at a fixed vertical position on the frame. According to the preferred embodiment of the invention, UV ink is printed onto material and the cure of the ink is initiated by exposure to UV light radiated from UV curing lights mounted on the printhead carriage, one on each side of the printhead set. The lights are alternatively energized, depending on the direction of motion of the carriage across the substrate, so as to expose the printed surface immediately behind the heads. By so mounting the UV curing lights on the printhead carriage, the jetted ink can “spot cure” the ink, or to cure the ink immediately upon its contacting the substrate. Such spot curing “freezes the dots” in position and prevents their spreading on or wicking into or otherwise moving on the substrate. With certain substrates, conventional or broad spectrum UV curing lights include radiation that can heat the substrate. Such radiation includes infra-red radiation and radiation of such other wavelengths that tend to heat a particular substrate. In the case of many rigid substrates, such as foamboard and several other of the more commonly used substrates, energy radiating from the UV light curing source onto the substrate heats the substrate enough to deform it. Such deformation can deform rapidly, with the surface of the substrate rising or rippling within seconds of exposure. Usually, this deposition is temporary in that the substrate blisters or swells when heated but returns to its original condition immediately upon cooling. Where the UV exposure is carried out downstream of the printhead carriage, usually no harm results. In the case of spot curing, the UV exposure occurs close to the point of printing. Deformation of the substrate surface that occurs due to heat in spot curing can extend to the portion of the substrate that is still to be printed, thereby changing the printhead-to-substrate spacing and adversely affecting the quality of the ink jet printing operation. The present invention provides the use of cold UV sources for spot curing of UV curable ink on heat sensitive rigid substrates. Heat caused deformation of the substrate in the region of the printing operation is prevented with the use of a cold UV source, Such a cold UV source can, for example, be a limited bandwidth UV source, to limit energy of wavelengths that are not effective to cure the ink from otherwise striking and heating the substrate. This can be carried out with selective bandwidth sources or with the use of filters to remove energy of undesired wavelengths. Alternatively, heat removal can be employed to remove the heat that is produced by the curing radiation. The cold UV source is useful for printing onto substrates that can deform, even temporarily, when heated, and is particularly useful where spot curing of the ink can otherwise result in the deformation of the material on which printing is still to take place. Deformation at the printing site, even if temporary such that the material returns to its undeformed state when it cools, adversely affects the print quality because spot curing deforms the substrate as the ink jets are making single or multiple passes over the print area. This is particularly the case when printing onto foamboards that make up the largest application of printing onto rigid substrates. Such deformation of the board from heat during printing would force adjustment of the head height above the deformation zone. Higher head height usually results in poorer print quality. With a cold-UV spot-cure ink-jet system, the head-to-substrate distance can be minimized to maximize print quality. In prior practice, spot curing has not been used to ink jet print onto rigid substrates, except as proposed by applicants. Cold UV is known for curing UV ink downstream of a printing station to prevent permanent deformation to or buring of the substrate. Temporary deformation that will disappear after the substrate cools has not been a problem in the prior art. Such deformation is likely to be a problem where slight raising or warping of the surface takes place as ink is being jetted onto the substrate, which can occur during spot curing. When printing onto contoured material, the distance from the printheads to the substrate where the ink is to be deposited can be determined by measuring the distance from a sensor to the substrate ahead of the printheads and mapping the location of the surface. For bidirectional printheads that move transversely across the longitudinally advancing fabric, providing two distance measuring sensors, one on each of the opposite sides of the printheads, are provided to measure the distance to the contoured fabric surface when the printheads are moving in either direction. For some inks and for sufficiently rigid materials, a mechanical rolling sensor may be used, for example, by providing a pair of rollers, with one roller ahead of, and one head behind, the printhead so that the average distance between the two rollers and a reference point on the printhead can be used to control the distance of the printhead from the plane of the substrate. To achieve this, one or more printheads can be mounted to a carriage having the rollers on the ends thereof so that the mechanical link between the rollers moves the printhead relative to the plane of the substrate. In most cases, a non-contact sensor, such as a laser or photo eye sensor, is preferred in lieu of each roller. The outputs of two sensors on opposite sides of the printheads can be communicated to a processor, to measure the distance from the heads to the fabric ahead of the bidirectional heads, to drive a servo motor connected to the printhead to raise and lower the head relative to the substrate plane so that the printheads move parallel to the contoured surface and jet ink onto the fabric across a fixed distance. These and other objects of the present invention will be more readily apparent from the following detailed description of the preferred embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of one embodiment of an apparatus embodying principles of the present invention. FIG. 2 is a partial cross-sectional view along line 2-2 of FIG. 1 showing structure for maintaining printhead-to-substrate distance on a contoured substrate. FIG. 3 is a perspective view of the printhead carriage of the apparatus of FIG. 1. FIG. 4 is a cross-sectional view through the UV curing head of the printhead carriage of FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Ink jet printing onto large rigid substrates is described in the commonly assigned and copending U.S. patent applications Ser. Nos. 09/650,596, filed Aug. 30, 2000, and 09/822,795, filed Mar. 30, 2001, hereby expressly incorporated by reference herein. Ink jet printing onto large substrates, particularly textiles, is described in the commonly assigned and copending U.S. patent applications Ser. No. 09/390,571, filed Sep. 3, 1999, Ser. No. 09/823,268, filed Mar. 30, 2001 and Ser. No. 09/824,517, filed Apr. 2, 2001, and International Application Serial No. PCT/US00/24226, filed Sep. 1, 2000, each hereby expressly incorporated by reference herein. FIG. 1 illustrates an ink jet printing machine 100 for printing onto wide rigid substrates. The machine 100 includes a stationary frame 111 with a longitudinal extent represented by an arrow 112 and a transverse extent represented by an arrow 113. The machine 100 has a front end 114 into which the rigid panel 15 may be loaded onto a belt 121 of a conveyor system 120 having one or more flights which carry the panel 15 longitudinally through the machine 100. The belt 121 of the conveyor system 120 extends across the width of the frame 111 and rests on a smooth stainless steel vacuum table 105, which has therein an array of upwardly facing vacuum holes 106 which communicate with the underside of the belt 121. The belt 121 is sufficiently porous that the vacuum from the table 105 communicates through the belt 121 to the underside of the rigid panel 15 to assist gravity in holding the panel 15 in place against the top side of the belt 121. Preferably, the belt 121 has a high friction rubber-like surface 108 to help prevent a horizontal sliding of a panel resting on it, through which an array of holes 109 or open mesh is provided to facilitate communication of the vacuum from the table 105 to the substrate. The top surface of the belt 121 of the conveyor 120 is such that it provides sufficient friction between it and the underside of the panel 15 to keep the panel 15 from sliding horizontally on the conveyor 120. The conveyor 120 is further sufficiently non-elastic so that it can be precisely advanced. To this end, the belt 121 has a non-elastic open weave backing 107 to provide dimensional stability to the belt while allowing the vacuum to be communicated between the holes 106 of the table 105 and the holes 109 or open mesh in the surface of the belt 121. The forward motion of the panel 15 on the frame 111 is precisely controllable by indexing of the belt 121 by control of a servo drive motor 122 with signals from the controller 35. The belt 121 thereby retains the panels 15 in a precisely known longitudinal position on the belt 121 so as to carry the panels 15 through the longitudinal extent of the machine 100. Such indexing of the belt 121 should be controllable to an accuracy of about 0.0005 inches where used to move the panel 15 relative to a printhead on a fixed bridge (which embodiment is not shown). In the machine 100 illustrated in FIG. 1, the longitudinal movement of the belt 121 of the conveyor 120 is controlled by the conveyor drive 122 to move the panel into printing position and then to advance it downstream after it is printed. One or more additional separately controllable drives 132 may be provided to control the downstream flights, if any, of the conveyor 120. Along the length of travel of the conveyor 120 may be provided two or more stations, including an ink jet printing station 125 and one or more curing or drying stations, which may include UV light curing stations 124 and/or a heating station 126. The printing station 125 includes a bridge 128. Where the belt 121 is operable to precisely index the panel 15 relative to the bridge 128, the bridge may be fixed to the frame 111 and extend transversely across it. A printhead carriage 129 is transversely moveable across the bridge 128 and has one or more sets 130 of ink jet printing heads thereon. The carriage 129 is preferably fixed to the armature of a linear servo motor 131 which has a linear array of stator magnets extending transversely across the bridge 128, so that the carriage 129 is transversely moveable across the bridge 128 by positioning and drive control signals sent to the servo 131 by the controller 35, described above. In the illustrated embodiment, the bridge 128 is mounted to the moveable armatures 133a, 134a that ride on longitudinal tracks 133b, 134b of linear servo motors 133, 134 at each side of the conveyor 120. Once a panel 15 is positioned under the bridge 128 by movement of the belt 121, the bridge 128 is indexed in the longitudinal direction as transverse bands of an image are printed in successive scans of printheads 130, described below. This indexing should be as accurate as needed to insure that the scans register one with another and can be interlaced, as required, to produce the desired print quality and resolution. Such accuracy is preferred to be about 0.0005 inches. Lower resolution, and thus less accuracy, is acceptable for printing on textile surfaces rather than on smoother surfaces such as vinyl. FIG. 2 illustrates a set 130 of four ink jet printing heads 130a-130d configured to respectively apply the four colors of a CMYK color set. The ink jet printing heads 130a-d each include a linear array of one hundred twenty-eight (128) ink jet nozzles that extend in the longitudinal direction relative to the frame 111 and in a line perpendicular to the direction of travel of the carriage 129 on the bridge 128. The nozzles of each of the heads 130 are configured and controlled to simultaneously but selectively jet UV ink of one of the CMYK colors side-by-side across the substrate 15, and to do so in a series of cycles as the nozzles scan the substrate 15. The heads 130a-d of a set are arranged side-by-side to print consecutively across the same area of the substrate 15 as the carriage 129 moves across the bridge 128, each depositing one of the four colors sequentially on each dot position across the substrate 15. Each of the heads 130a-d is moveably mounted to the carriage to individually move vertically or perpendicular to the plane of the substrate 15. The distance of each head 130a-d from the plane of the substrate 15 is controlled by a respective one of a set of servos 137a-d mounted to the carriage 129 to follow one behind the other over the same contour of the substrate 15. The servos 137a-d are responsive to signals from the controller 35 which control the positions of the heads 130a-d to maintain each a controlled distance from the surface of the substrate 15 where the surface 16 of the substrate 15 is contoured. Usually, it is desirable to maintain the heads a fixed distance from the surface 16 on which they are to print. This is achieved by providing optical sensors 138a, 138b on the opposite transverse sides of the carriage 129. The printhead set 130 is bidirectional and prints whether moving to the right or to the left. As the printhead carriage 129 moves on the bridge 128, the leading one of the sensors 138a or 138b measures the distance from the sensor 138 and the surface 16 of the substrate 15 at a point directly in line with, typically directly below, the sensor 138. This measurement is communicated to the controller 35, which records the measured distance and the coordinates on the surface 16 of the substrate 15 at which the measurement was taken. These coordinates need only include the transverse position on the substrate 15 where the information is to be used in the same pass or scan of the carriage in which the measurement was taken. However, the controller 35 may also record the longitudinal coordinate by taking into account the position of the panel 15 on the frame 111 relative to the bridge 128. In response to the measurements, the controller 35 controls the servos 137 to vertically position the each of the heads 130 to a predetermined distance from the contoured surface 16 of the substrate 15 as the respective head arrives at the transverse coordinate on the substrate 15 at which each measurement was taken. As a result, the nearest of the heads 130 to the leading sensor 138, which are spaced a distance B from the sensor 138, follows the contour of the fabric at a delay of V/B seconds after a given measurement was taken, where V is the velocity of the carriage 129 on the bridge 128. Similarly, the heads 130 are spaced apart a distance A and will each sequentially follow the same contour as the first head at V/A seconds after the preceding head. The extent of the heads 130 in the longitudinal direction determines the accuracy with which the heads can follow the contours of the substrate 15. Greater accuracy can be maintained, and more variable contours can be followed, by using narrower heads, for example, of 64 or 32 jets per head in the longitudinal direction. Accordingly, multiple sets of heads 130 can be arranged in a rectangular or other array on the carriage 129, with heads of the different sets being arranged side-by-side across the carriage 129 in the longitudinal direction of the substrate 15 and frame 111. For example, two sets of heads having 64 jets per head each or four sets of heads having 32 jets per head each will produce the same 128 dot wide scan, but with greater ability to maintain spacing from head to substrate where the contours vary in the longitudinal direction on the substrate 15. Printing on rigid panels, even where the surface is not textured or contoured, can benefit from the sensing and adjustment of the distance from print nozzle to surface of the panel since the rigid frame of the panel and the thickness of the panel when supported on the frame of a printing apparatus makes the position of the upper surface of the panel unpredictable. Where UV curable ink is used, the UV curing station 124 is provided as illustrated in FIG. 1. It may include a UV curing head 23 transversely moveable independently of the printheads 130 across the downstream side of the bridge 128 or otherwise located downstream of the printing station 125, and/or may include UV light curing heads 123a and 123b mounted on the carriage 129. Where employed to separately move across the substrate, the curing head 23 is preferably intelligently controlled by the controller 35 to selectively operate and quickly move across areas having no printing and to scan only the printed images with UV light at a rate sufficiently slow to UV cure the ink, thereby avoiding wasting time and UV energy scanning unprinted areas. If the head 23 is included in the printing station 25 and is coupled to move with the printheads 30, UV curing light can be used in synchronism with the dispensing of the ink immediately following the dispensing of the ink. Where UV curing heads are employed on the carriage 129, as the carriage 129 moves transversely on the bridge 128, only the curing head 123a, 123b that trails the printheads 130 is operated so that the UV light exposes ink after its deposition onto the substrate 15. Such carriage mounting of the curing heads 123a, 123b enables the freezing of the dots of ink where they are deposited, reducing drop spread and wicking of the ink. The curing heads 123a, 123b may also be moveable toward and away from the plane of the substrate 15 in the same manner as the printheads 130a-d, controllable by servos 139a, 139b, respectively, to maintain their spacing from the surface 16, as illustrated in FIG. 2. Effective curing of UV ink requires that the UV light be either parallel beam light, have a long depth of field, or be more precisely focused on the surface bearing the ink. Precise focus is more energy efficient, in which case, moving the UV heads 123a, 123b to maintain a constant spacing from the surface 16 maintains the focus of the curing UV light. UV light curing heads are typically configured to sharply focus a narrow, longitudinally extending beam of UV light onto the printed surface. Therefore, instead of physically moving the UV light curing heads or sources 123a, 123b, the focal lengths of the light curing heads 123a, 123b may be varied to follow the contours of the substrate 15. The light curing head 123, where used, may similarly be configured to move perpendicular to the surface 16 of the substrate 15. Further, in accordance with the preferred embodiment of the invention, the UV curing heads, particularly when mounted on the carriage, are cold-UV light, which, through the use of filters or narrow bandwidth radiation, avoid heating a substrate 15. This is particularly useful where the apparatus 100 is to be used for printing onto heat sensitive substrates such as foamboard. Where carriage mounted UV curing heads 123a, 123b are used and the freezing of the dots at the point of jetting is desired, deforming the substrate at the location where the ink drops are being deposited would degrade the printed image. Such cold-UV curing light systems use cold mirrors, infrared cut filters, and water cooled UV curing to keep the temperature of the substrate low, avoiding substrate deformation. FIG. 3 illustrates the details of an arrangement of the carriage 129 on which cold UV curing heads 150 are used in place of the heads 123a, 123b described above. A head of the type 150 may also be used in place of the separate curing head 123 described above. Such UV heads 150 in the embodiment illustrated are fixed, rather than vertically moveable, and emit parallel UV light rather than focused light. The heads 150 each include a ten inch linear bulb 151 approximately one inch in diameter located at the focal point of a downwardly facing ten inch linear reflector 152 having a lower surface 153 having a generally parabolic cross section as illustrated in FIG. 4. The reflector 152 is formed of extruded aluminum and has a pair of cooling fluid return channels 153 formed therein that run the length thereof. Extending the length of the head 150 and positioned directly below the bulb 151 is a hollow UV transparent tube 155 which may be formed of a temperature and radiation tolerant material, for example, quartz. The tube 155 has a fluid 156, for example, de-ionized water, flowing therein. The tube is connected in a circuit with the cooling channels 153 and a recirculating pump 157 so that the cooling fluid 156 flows through the tube 155, where it absorbs approximately 80-85% of the infrared energy passing therethough, while only absorbing about 6-8% of the UV light, and then through the channels 153 further pick up heat from the wall of the reflector 152. Before flowing to the pump 157, the fluid from the channels 153 flows through a heat exchanger 158 where it is cooled. The bulbs 151 consume approximately 125 to 200 watts per linear inch, but may be operated at different power levels. Assemblies suitable for the heads 150 are available from Printing Research, Inc., Dallas, Tex., www.superblue.net. In operation, UV light is emitted from the bulbs 151 along with radiant energy of other wavelengths, such as infrared light, that would result in the heating of the substrate 15. Such radiant energy of these other wavelengths is, however, mostly absorbed in the fluid 156 and removed before impinging on the substrate 15. As a result, no thermal distortion, even of a temporary nature, occurs at the surface 16 of the substrate 15. The heat curing or drying station 126 may be fixed to the frame 111 downstream of the printing station 125 and the UV light curing station, if any, may be located off-line. Such a drying station 126 may be used to dry solvent based inks with heated air, radiation or other heating techniques. It may also be used to further cure or dry UV inks. The heat curing or drying station 26 may be fixed to the frame 11 downstream of the UV light curing station or may be located off-line. With 97% UV cure, the ink will be sufficiently colorfast so as to permit the drying station to be off-line. When on-line, the drying station should extend sufficiently along the length of fabric to adequately cure the printed ink at the rate that the fabric is printed. When located off-line, the heat curing station can operate at a different rate than the rate of printing. Heat cure at the oven or drying station 26 maintains the ink on the fabric at about 300° F. for up to three minutes. Heating of from 30 seconds to three minutes is the anticipated advantageous range. Heating by forced hot air is preferred, although other heat sources, such as infrared heaters, can be used as long as they adequately penetrate the fabric to the depth of the ink. The above description is representative of certain preferred embodiments of the invention. Those skilled in the art will appreciate that various changes and additions may be made to the embodiments described above without departing from the principles of the present invention. Therefore, the following is claimed: | <SOH> BACKGROUND OF THE INVENTION <EOH>Applying ink to a substrate by ink jet printing requires a proper spacing between the ink jet nozzles and the surface of the substrate to which the printing is applied. Normally, this spacing must be set to within one or two millimeters to maintain effective printing by an ink jet process. If the distance from the nozzles to the surface being printed is too great, deviations from ideal parallel paths of the drops from different nozzles become magnified. Further, the longer the flight path of the drops from the printhead to the substrate, the more dependent the accuracy of the printing becomes on the relative speed between the printhead and the substrate. This dependency limits the rate of change in printhead-to-substrate velocity, including changes in direction. Also, the velocity of the drops moving from the printhead nozzles to the substrate declines with the distance traveled from the nozzles, and the paths of such drops become more greatly affected by air currents and other factors with increased nozzle to substrate distance. Additionally, droplet shape changes the farther the drop moves from the nozzle, which changes the effects of the drop on the substrate. Accordingly, variations in the distance from the printhead to the substrate can cause irregular effects on the printed image. In addition to problems in jetting ink onto contoured surfaces, the curing of UV inks requires delivery of sufficient curing energy to the ink, which is often difficult to achieve where the surface is contoured. Further, some substrates deform, even temporarily, when heated. Deformation caused by heat may be such that, for example, the material returns to its undeformed state when it cools. Nonetheless, even temporary deformation can adversely affect the print quality if it exists when ink is being jetted onto the substrate. Where spot curing of UV inks is employed, which is performed by exposing ink to UV immediately upon its contacting the substrate, UV that is accompanied by heat producing radiation can deform substrates such as foamboard while the ink jets are making single or multiple passes over the deformed print area. For these reasons, ink jet printing has not been successful on contoured materials and other three-dimensional substrates, particularly when printing with UV curable inks. | <SOH> SUMMARY OF THE INVENTION <EOH>An objective of the present invention is to provide for the ink jet printing onto substrates that tend to deform when heated. A particular objective of the present invention is to maintain desired printhead-to-substrate spacing when jetting ink onto rigid substrates, particularly with UV curable inks. According to the principles of the present invention, printed images are applied to rigid substrates with printing elements that may be moveable relative to the plane of the substrate being printed. In certain embodiments, the invention provides a wide-substrate ink jet printing apparatus with printheads that move toward and away from the plane of a substrate to maintain a fixed distance between the nozzles of the printhead and the surface onto which the ink is being jetted. The variable distance over the plane of the substrate allows a controlled and uniform distance across which the ink is jetted. According to the invention, the printing element may include an ink jet printhead set having a plurality of heads, typically four, each for dispensing one of a set of colors onto the substrate to form a multi-colored image. To maintain the constant distance or to otherwise control the distance, one or more sensors may be provided to measure the distance from the printhead or from the printhead carriage track to the point on the substrate on which ink is to be projected. Such sensors generate reference signals that are fed to a controller that controls a servo motor on the printhead carriage. The printhead may be moveably mounted to the carriage, for example, on a ball screw mechanism, and be moveable toward and away from the plane of the substrate by operation of the servo motor. Each printhead of the set may include four different color printheads that are separately moveable relative to a common printhead carriage, and are each connected to one of a set of four servo motors by which its position relative to the plane of the substrate is capable of control relative to the positions of the other printheads. The printheads of the set may be arranged side-by-side in the transverse direction on the carriage so that one head follows the other across the width of the substrate as the carriage scans transversely across the substrate. Each printhead has, in the preferred embodiment, a plurality of ink jet nozzles thereon for dispensing a given color of ink in a corresponding plurality of dots, for example, 128 in number, that extend in a line transverse to the carriage, which is in a longitudinal direction perpendicular to the scan direction of the carriage. Two laser or optical sensors are provided on the carriage, one on each side of the heads, so that a distance measurement of the surface to the substrate can be taken ahead of the printheads when the heads are scanning in either direction. The controller records the contour of the substrate ahead of the printheads and varies the position of each printhead, toward and away from the substrate plane, as each printhead passes over the points at which the measurements were taken, so that each of the independently moveable heads follows the contour and maintains a fixed distance from the surface being printed. While it is preferred to adjust the position of the printhead or nozzle thereof relative to the substrate which is fixed on a printing machine frame, the substrate surface can alternatively be positioned relative to a printhead that is maintained at a fixed vertical position on the frame. According to the preferred embodiment of the invention, UV ink is printed onto material and the cure of the ink is initiated by exposure to UV light radiated from UV curing lights mounted on the printhead carriage, one on each side of the printhead set. The lights are alternatively energized, depending on the direction of motion of the carriage across the substrate, so as to expose the printed surface immediately behind the heads. By so mounting the UV curing lights on the printhead carriage, the jetted ink can “spot cure” the ink, or to cure the ink immediately upon its contacting the substrate. Such spot curing “freezes the dots” in position and prevents their spreading on or wicking into or otherwise moving on the substrate. With certain substrates, conventional or broad spectrum UV curing lights include radiation that can heat the substrate. Such radiation includes infra-red radiation and radiation of such other wavelengths that tend to heat a particular substrate. In the case of many rigid substrates, such as foamboard and several other of the more commonly used substrates, energy radiating from the UV light curing source onto the substrate heats the substrate enough to deform it. Such deformation can deform rapidly, with the surface of the substrate rising or rippling within seconds of exposure. Usually, this deposition is temporary in that the substrate blisters or swells when heated but returns to its original condition immediately upon cooling. Where the UV exposure is carried out downstream of the printhead carriage, usually no harm results. In the case of spot curing, the UV exposure occurs close to the point of printing. Deformation of the substrate surface that occurs due to heat in spot curing can extend to the portion of the substrate that is still to be printed, thereby changing the printhead-to-substrate spacing and adversely affecting the quality of the ink jet printing operation. The present invention provides the use of cold UV sources for spot curing of UV curable ink on heat sensitive rigid substrates. Heat caused deformation of the substrate in the region of the printing operation is prevented with the use of a cold UV source, Such a cold UV source can, for example, be a limited bandwidth UV source, to limit energy of wavelengths that are not effective to cure the ink from otherwise striking and heating the substrate. This can be carried out with selective bandwidth sources or with the use of filters to remove energy of undesired wavelengths. Alternatively, heat removal can be employed to remove the heat that is produced by the curing radiation. The cold UV source is useful for printing onto substrates that can deform, even temporarily, when heated, and is particularly useful where spot curing of the ink can otherwise result in the deformation of the material on which printing is still to take place. Deformation at the printing site, even if temporary such that the material returns to its undeformed state when it cools, adversely affects the print quality because spot curing deforms the substrate as the ink jets are making single or multiple passes over the print area. This is particularly the case when printing onto foamboards that make up the largest application of printing onto rigid substrates. Such deformation of the board from heat during printing would force adjustment of the head height above the deformation zone. Higher head height usually results in poorer print quality. With a cold-UV spot-cure ink-jet system, the head-to-substrate distance can be minimized to maximize print quality. In prior practice, spot curing has not been used to ink jet print onto rigid substrates, except as proposed by applicants. Cold UV is known for curing UV ink downstream of a printing station to prevent permanent deformation to or buring of the substrate. Temporary deformation that will disappear after the substrate cools has not been a problem in the prior art. Such deformation is likely to be a problem where slight raising or warping of the surface takes place as ink is being jetted onto the substrate, which can occur during spot curing. When printing onto contoured material, the distance from the printheads to the substrate where the ink is to be deposited can be determined by measuring the distance from a sensor to the substrate ahead of the printheads and mapping the location of the surface. For bidirectional printheads that move transversely across the longitudinally advancing fabric, providing two distance measuring sensors, one on each of the opposite sides of the printheads, are provided to measure the distance to the contoured fabric surface when the printheads are moving in either direction. For some inks and for sufficiently rigid materials, a mechanical rolling sensor may be used, for example, by providing a pair of rollers, with one roller ahead of, and one head behind, the printhead so that the average distance between the two rollers and a reference point on the printhead can be used to control the distance of the printhead from the plane of the substrate. To achieve this, one or more printheads can be mounted to a carriage having the rollers on the ends thereof so that the mechanical link between the rollers moves the printhead relative to the plane of the substrate. In most cases, a non-contact sensor, such as a laser or photo eye sensor, is preferred in lieu of each roller. The outputs of two sensors on opposite sides of the printheads can be communicated to a processor, to measure the distance from the heads to the fabric ahead of the bidirectional heads, to drive a servo motor connected to the printhead to raise and lower the head relative to the substrate plane so that the printheads move parallel to the contoured surface and jet ink onto the fabric across a fixed distance. These and other objects of the present invention will be more readily apparent from the following detailed description of the preferred embodiments of the invention. | 20040419 | 20071106 | 20050203 | 93540.0 | 1 | TRAN, LY T | METHOD AND APPARATUS FOR INK JET PRINTING ON RIGID PANELS | UNDISCOUNTED | 1 | CONT-ACCEPTED | 2,004 |
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10,827,141 | ACCEPTED | Method of clarifying industrial laundry wastewater using cationic dispersion polymers and anionic flocculent polymers | Methods are described for removing contaminates from aqueous industrial wastewater process streams, specifically industrial laundries to yield a less contaminated aqueous effluent for discharge to a sewer and reduce the sludge generated therefrom. A premixed medium/high molecular weight and medium/high charged cationic coagulant solution polymer and an inorganic aluminum species is injected into the wastewater, and after at least a two second delay, a high molecular weight highly charged anionic flocculent polymer solution is injected into the wastewater which reduces sludge generation, while maintaining or exceeding effluent quality. Also, no coagulant, flocculent or sludge aids are needed to attain the results and the sludge can be dewatered in a plate and frame press. | 1. A method of clarifying industrial laundry wastewater containing surfactants, fats, oil and grease (FOG), total petroleum hydrocarbon (TPH) biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), ionized metals and other contaminants, without the use of additional coagulants, flocculents, coagulant aids, flocculent aids or sludge conditioning aids, and allowing for the correct dewatering of the sludge using a plate and frame sludge press, comprising the steps of: (a) adding to the wastewater an effective amount of a water dispersed cationic blend whose major components are of pDADMAC and ACH, between 50 ppm and 700 ppm to break the emulsified bond in the wastewater and produce coagulated particles having sufficient mass and cationic charge to react with an anionic flocculent to be added thereafter; (b) delaying any flocculent addition by at least a predetermined time to permit the cationic coagulant blend to substantially complete the coagulation of the particles in the wastewater in step (a); (c) adding to the wastewater an effective amount of an aqueous anionic flocculent, between 5 ppm and 50 ppm, of sufficient molecular weight and charge density to react with the cationic charged coagulated particles to form flocculated waste particles of effective size to form sludge while leaving a disposable clarified water, thereby lowering the amount of sludge generated by at least 30% of that normally generated using existing coagulation and flocculation techniques of adding additional coagulants, flocculents, coagulant aids, flocculent aids or sludge aids, including but not limited to, poly aluminum chloride, epi-amine coagulant, bentonite clay, perlite, ferrous sulfate, ferric chloride diatomaceous earth and others; (d) separating the sludge from the clarified water; (e) passing the sludge to a plate and frame sludge press; and (f) dewatering the sludge by the press, thereby forming a disposable sludge cake; (g) disposing of the sludge cake and the clarified water. 2. The method of claim 1 wherein the predetermined time in step (b) is two seconds. 3. The method of claim 1 wherein the cationic blend is 20% pDADMAC and 20% ACH. 4. The method of claim 1 wherein the anionic flocculent is essentially poly(acrylamide-co-acrylate). 5. The method of claim 1 wherein the anionic flocculent is dry, further comprising the step of: (g) wetting the flocculent to a solution strength of between 0.05 and 0.5% prior to the adding step (c). 6. The method of claim 1 wherein the predetermined time in step (b) is two seconds and the anionic flocculent is essentially poly(acrylamide-co-acrylate) added as a wetted solution having a strength of between 0.05 and 0.5% prior to adding in step (c). 7. The method of claim 1 further comprising the step of: (g) disposing of the water from the dewatering step (f). 8. The method of claim 1 wherein the anionic flocculent is dry, further comprising the step of: (g) wetting the flocculent to a solution strength of 0.2% prior to the adding step (c). 9. The method of claim 1 wherein the predetermined time in which step (b) is two seconds, the cationic blend is 20% pDADMAC and 20% ACH and the anionic flocculent is essentially a dry poly(acrylamide-co-acrylate), further comprising the steps of: (g) wetting the flocculent to a solution strength of between 0.05 and 0.5% prior to the adding step (c); and (h) disposing of the water from the dewatering step (f). 10. A method of clarifying industrial laundry wastewater containing surfactants, fats, oil and grease (FOG), total petroleum hydrocarbon (TPH) biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), ionized metals and other contaminants, without the use of additional coagulants, flocculents, coagulant aids, flocculent aids or sludge conditioning aids, and allowing for the correct dewatering of the sludge using a plate and frame sludge press, consisting essentially of the steps of: (a) adding to the wastewater an effective amount of a water dispersed cationic blend whose major components are of DADMAC and ACH, between 50 ppm and 700 ppm to break the emulsified bond in the wastewater and produce coagulated particles having sufficient mass and cationic charge to react with an anionic flocculent to be added thereafter; (b) delaying any flocculent addition by at least a predetermined time to permit the cationic coagulant blend to substantially complete the coagulation of the particles in the wastewater in step (a); (c) adding to the wastewater an effective amount of an aqueous anionic flocculent, between 5 ppm and 50 ppm, of sufficient molecular weight and charge density to react with the cationic charged coagulated particles to form flocculated waste particles of effective size to form sludge while leaving a disposable clarified water; (d) separating the sludge from the clarified water; (e) passing the sludge to a plate and frame sludge press; (f) dewatering the sludge by the press, thereby forming a disposable sludge cake; and (g) disposing of the sludge cake and the clarified water. 11. The method of claim 10 wherein the predetermined time in step (b) is two seconds. 12. The method of claim 10 wherein the cationic blend is 20% PDADMAC and 20% ACH. 13. The method of claim 10 wherein the anionic flocculent is essentially poly(acrylamide-co-acrylate). 14. The method of claim 10 wherein the anionic flocculent is dry, further consisting essentially of the step of: (g) wetting the flocculent to a solution strength of between 0.05 and 0.5% prior to the adding step (c). 15. The method of claim 10 wherein the predetermined time in step (b) is two seconds and the anionic flocculent is essentially poly(acrylamide-co-acrylate) added as a wetted solution having a strength of between 0.05 and 0.5% prior to adding in step (c). 16. The method of claim 10 further consisting essentially of the step of: (g) disposing of the water from the dewatering step (f). 17. The method of claim 10 wherein the anionic flocculent is dry, further consisting essentially of the step of: (g) wetting the flocculent to a solution strength of 0.2% prior to the adding step (c). 18. The method of claim 10 wherein the predetermined time in which step (b) is two seconds, the cationic blend is 20% pDADMAC and 20% ACH and the anionic flocculent is essentially a dry poly(acrylamide-co-acrylate), further consisting essentially of the steps of: (g) wetting the flocculent to a solution strength of between 0.05 and 0.5% prior to the adding step (c); and (h) disposing of the water from the dewatering step (f). 19. A method of clarifying industrial laundry wastewater containing surfactants, fats, oil and grease (FOG), total petroleum hydrocarbon (TPH) biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), ionized metals and other contaminants, without the use of additional coagulants, flocculents, coagulant aids, flocculent aids or sludge conditioning aids, and allowing for the correct dewatering of the sludge using a plate and frame sludge press, consisting of the steps of: (a) adding to the wastewater an effective amount of a water dispersed cationic blend whose major components are of DADMAC and ACH, between 50 ppm and 700 ppm to break the emulsified bond in the wastewater and produce coagulated particles having sufficient mass and cationic charge to react with an anionic flocculent to be added thereafter; (c) delaying any flocculent addition by at least a predetermined time to permit the cationic coagulant blend to substantially complete the coagulation of the particles in the wastewater in step (a); (c) adding to the wastewater an effective amount of an aqueous anionic flocculent, between 5 ppm and 50 ppm, of sufficient molecular weight and charge density to react with the cationic charged coagulated particles to form flocculated waste particles of effective size to form sludge while leaving a disposable clarified water; (d) separating the sludge from the clarified water; (e) passing the sludge to a plate and frame sludge press; (f) dewatering the sludge by the press, thereby forming a disposable sludge cake; and (g) disposing of the sludge cake and the clarified water. 20. The method of claim 19 wherein the predetermined time in step (b) is two seconds. 21. The method of claim 19 wherein the cationic blend is 20% pDADMAC and 20% ACH. 22. The method of claim 19 wherein the anionic flocculent is essentially poly(acrylamide-co-acrylate). 23. The method of claim 19 wherein the anionic flocculent is dry, further consisting of the step of: (g) wetting the flocculent to a solution strength of between 0.05 and 0.5% prior to the adding step (c). 24. The method of claim 19 wherein the predetermined time in step (b) is two seconds and the anionic flocculent is essentially poly(acrylamide-co-acrylate) added as a wetted solution having a strength of between 0.05 and 0.5% prior to adding in step (c). 25. The method of claim 19 further consisting of the step of: (g) disposing of the water from the dewatering step (f). 26. The method of claim 19 wherein the anionic flocculent is dry, further consisting of the step of: (g) wetting the flocculent to a solution strength of 0.2% prior to the adding step (c). 27. The method of claim 19 wherein the predetermined time in which step (b) is two seconds, the cationic blend is 20% PDADMAC and 20% ACH and the anionic flocculent is essentially a dry poly(acrylamide-co-acrylate), further consisting of the steps of: (g) wetting the flocculent to a solution strength of between 0.05 and 0.5% prior to the adding step (c); and (h) disposing of the water from the dewatering step (f). | CROSS-REFERENCE TO RELATED APPLICATION Not Applicable. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not Applicable. REFERENCE TO A MICROFICHE APPENDIX Not Applicable. TECHNICAL FIELD This invention is directed to methods of clarifying industrial wastewater, specifically industrial laundry wastewater that includes wastewater from light to heavy product mix industrial laundry plants utilizing both full and split streams as defined by a client-user. BACKGROUND OF THE INVENTION In the laundry wastewater treatment field of solids/liquid separation, suspended and emulsified solids are removed from water by a variety of processes, including sedimentation, straining, flotation, filtration, coagulation, flocculation, and emulsion breaking among others. Additionally, after solids are removed from the wastewater they must often be dewatered. Liquids treated for solids removal often have as little as several parts per million (ppm) of suspended solids or dispensed oils, or may contain several thousand ppm of suspended solids or oils. Solids being generated as sludge may contain anywhere from 0.1 to 6 weight percent solids prior to dewatering, and from 20 to 50 weight percent solids material after dewatering by a plate and frame press. Solids/liquid separation processes are designed to remove solids from liquids and the more solids generated in the process, the more costly its disposal. While strictly mechanical means have been used to effect solids/liquid separation, the modern methods often rely on mechanical separation techniques that are augmented by synthetic and natural polymeric materials to accelerate the rate at which solids can be removed from water. These processes include the treatment of wastewater with cationic organic and inorganic coagulants that coagulate suspended particulates to form larger particles that then may be brought together by an anionic flocculent to create particles large enough to be removed from the waste stream by mechanical means, i.e., flotation or clarification, and make the effluent suitable for industrial reuse or disposal in compliance with local permit discharge requirements. In the industrial laundry industry, the chemical treatment of wastewater to a typical municipal standard of 100 ppm of oil and grease (EPA method 1664) prior to the introduction of this invention has been: the hydraulic equalization of untreated wastewater followed by the metered flow of the wastewater through a pipe or tanks to provide for retention time for the injection of a variety of chemicals including combinations and individually, both organic and inorganic coagulants and aids, followed by an organic component flocculent to produce coagulation and flocculation. These inorganic components used for coagulation or coagulation aids, typically have simple hydration factors of approximately 6-12 water molecules and may also be used in conjunction with a separate component, i.e. perlite or diatomaceous earth or bentonite clay, to act as a “body builder” to produce sludge so that in down stream processes it may be dewatered. A variety of organic and inorganic coagulants and aids exist throughout the marketplace. Historical data has shown that used in correct combination these chemistries can produce suitable effluent with sludge generation of approximately 1.1 to 2.5% of influent flow, whereas by use of this invention sludge production is reduced to approximately 0.25 to 1.0% of influent flow. Chemical treatment generally refers to the removal of nonsettleable material by coagulation and flocculation. Chemical treatment for wastewater clarification is typically employed when colloidal and microemulsified solids need to be removed so that the total petroleum hydrocarbons (TPH), fat, oil and grease (FOG), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and other contaminants being discharged to a receiving stream need to be minimized. Typically, such treatment comprises using a cationic coagulant with one or more inorganic components, injected in combination or individually, followed by an anionic flocculent. Coagulation is the process of destabilization of the colloid waste particle by causing the coagulant (at 50-1000 ppm) to absorb by means of charge neutralization to form microfloc and impart residual cationic surface charge of the coagulated particles. The second step is to introduce a coagulant aid, i.e., ferric chloride, aluminum sulfate, ferrous sulfate, calcium chloride, polyaluminum chloride, typically at a rate of 75-700 ppm depending on the species, to increase the ability to form a more highly cationic surface that will cause the further adsorption of the coagulated particles onto the surface of an additional chemical, usually bentonite clay, at 200-900 ppm through a “sponge” effect. Flocculation occurs when the highly charged anionic flocculent bridges the previously formed cationic particles. Once neutralized, particles no longer repel each other and can come together to form larger agglomerated solids or sludge, which may then be removed from the water. The third step that is occasionally taken is the addition of sludge thickeners that assist in allowing the sludge to dewater, i.e. perlite, bentonite clay, diatomaceous earth and others. This invention is specifically directed to eliminating the second and/or third steps, i.e., the addition of coagulant aids and or sludge thickeners and a resultant reduction of the formation of sludge by up to 80% compared to previous historically used methods. Clarification chemicals are typically utilized in conjunction with mechanical clarifiers including dissolved air flotation systems (DAFs), induced air flotation systems (IAFs), and settlers for the removal of solids from the treated water. The clarification chemicals coagulate and/or flocculate the suspended solids into larger particles, which can then be removed from the water by gravitational settling, flotation, or other mechanical means. Processes for the preparation of high molecular weight cationic dispersion polymer flocculents are described in U.S. Pat. Nos. 5,006,590 and 4,929,655. High molecular weight, high active polymer cationic solution polymers for water clarification, dewatering and retention and drainage are disclosed in U.S. Pat. No. 6,171,505. BRIEF SUMMARY OF THE INVENTION The invention is directed to methods of clarifying industrial wastewater, specifically industrial laundry wastewater, to produce a compliant effluent and a reduction of sludge of between 30%-80%, using a two part system of a pDADMAC/ACH blended coagulant followed by a poly(acrylamide-co-acrylate) flocculent. Furthermore, the sludge produced using this invention will dewater in a typical plate and frame press without the use of any other organic or inorganic compounds added to the waste stream or sludge. This invention pertains to the use of a cationic aqueous solution containing a mostly equal blend of a 50% ratio of approximately a 2-35% concentration of solids by weight of polydiallydimethylammonium chloride (pDADMAC) organic polymer and a combination of epichlorohydrin-quaternaryammonium species where pDADMAC is the major constituent, together with approximately 540% concentration of solids by weight of aluminum chlorohydrate (also known by other names i.e. ACH, also known as partially neutralized polyaluminum chloride) an inorganic compound utilized as a coagulant (along with a combination of other chloride species where ACH is the major constituent) in the chemical demulisification of laundry wastewater to produce catatonic charged particles. The wastewater is cleaned using a medium to high molecular weight medium to very highly charged cationic solution coagulant (polymer) premixed with an inorganic aluminum species as one product, followed by a high to very high molecular weight anionic flocculent, I.e., poly(acrylamide-co-acrylate), (also known herein as sodium acrylate flocculent) with a 35% charge or higher (preferably 50% or higher), added in solution to produce particulate of sufficient size to be removed by physical means without the use of secondary, tertiary, or quaternary coagulation or flocculation aids. The wastewaters, to which this invention is directed, may be produced by the industrial cleaning of products including but not limited to: uniforms, shop towels, ink towels, mats, rugs, bar mops, aprons, coveralls and coats, used to protect personnel from manufacturing or commercial wastes. The creation of the wastewater stream can be through the use of all available commercial equipment that is used for washing the various products. These streams must then be collected in such a way as to promote the batch collection or intermittent or continuous flow of the stream. This collection of wastewater then may be further treated by batch or flow proportion as to allow for the injection and mixing of treatment chemicals by primary coagulation and flocculation only. This invention cleans the wastewater and reduces the sludge generation by as much as 80% from traditional methods of industrial laundry wastewater treatment, resulting in the elimination of additional in-stream and downstream additives. Furthermore, at the proper doses, this invention allows the sludge to be dewatered in a typical plate and frame press or other equipment used for the dewatering of sludge. The specific invention herein relates to the wastewater batch, or the in-stream use of the coagulant polymer compound containing pDADMAC coagulant and ACH injected into the wastewater stream in a diluted or an undiluted form, at any point prior to the sodium acrylate acrylamide flocculent injection with at least a two (2) second interval between the injections. The coagulant must be injected in the correct empirical quantity and given sufficient predetermined time to begin and complete the coagulation of the waste particles and the flocculent must be injected in the correct empirical quantity and given sufficient time to begin and complete the flocculation of the coagulated particles prior to dewatering. The coagulant and flocculent must be injected in sufficient quantity to create the conditions in the sludge that allow for the dewatering of the sludge generated by this process. These injection or dosing ratios are critical to the overall performance of the invention. The dry anionic flocculent is made into any solution strength commonly between 0.05-0.5%, 0.2% being preferred, and injected post coagulant by at least a two (2) second interval and in sufficient empirical quantities as to cause coagulated wastewater to form flocculated waste particles of sufficient size to settle in clarification or rise by flotation, as by dissolved/induced air or other means. The combination of the coagulant and the flocculent in the waste-stream produces a sludge volume 30-80% less than with those previous laundry wastewater treatments which utilize additional treatment chemicals or aids. The process testing of this invention has shown these reductions to be typical of the specific application of the invention disclosed herein. The flocculents of this invention must be of sufficient charge density, molecular weight and added in sufficient quantities, as to aid in all dewatering mechanisms, typically being a plate and frame press often found in typical plants. BRIEF DESCRIPTION OF THE DRAWING The novel features which are believed to be characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing, which illustrates schematically an industrial laundry wastewater treatment system embodying features of this invention. DETAILED DESCRIPTION OF THE INVENTION In accordance with the present invention, methods are provided for removing contaminants from an aqueous solution. Methods are provided for removing: surfactants, phenolics, total petroleum hydrocarbons, fats oil and grease, TSS contributors, BOD contributors, COD contributors, and TOC contributors from an aqueous solution. The surfactants, phenolics, total petroleum hydrocarbons, fats, oil and grease (FOG), TSS contributors, BOD contributors, COD contributors, and TOC contributors from an aqueous solution are removed by adsorption onto a carrier precipitate which is formed in situ within the aqueous solution. In each of the embodiments of the invention the preferred method involves rapidly forming the precipitate. The method of the invention can be used to remove the following contaminants from the laundry wastewater stream: TSS contributors, BOD contributors, COD contributors, TOC contributors, and/or fats, oil and grease (FOG). The invention will now be described first with respect to FOG, TSS contributors, BOD contributors. COD contributors, and TOC contributors. Unless otherwise stated, all process and apparatus parameters disclosed for FOG removal are equally effective for the removal of the other contaminants as well. Likewise, unless otherwise stated, all process and apparatus parameters disclosed for the removal of the other non-volatile contaminants are equally effective for heavy metal removal as well. “Coprecipitation” as used with respect to the invention described herein refers to the chemical phenomenon where, within an aqueous solution containing a cationic carrier precipitate precursor, an anionic carrier precipitate precursor, and one or more coprecipitant precursors, the cationic and anionic carrier precipitate precursors are caused to chemically react and precipitate out of the aqueous solution as carrier precipitate particles; and, as the carrier precipitate particles are formed, coprecipitant precursors are removed from the aqueous solution by adsorption onto the surface of the carrier precipitate particle and/or by occlusion within the interior of the carrier precipitate particle. The coprecipitant reaction is very rapid. Typically, more than 85 weight percent, and usually more than ninety-nine (99) weight percent, of the oil and grease are removed from the waste solution within about one minute after the formation of the agglomerated particle. Finally, the methods of the invention are superior to conventional precipitation methods in that these methods also produce less precipitate sludge. The lower sludge production stems, in part, from the removal of separately or blended inorganic components including but not limited to: ferric chloride, ferrous sulfate, polyaluminum chloride, bentonite clay, perlite, diatomaceous earth, aluminum chloride (except for the blend of 20% pDADMAC and 20% aluminum chlorohydrate used in accord with this invention). The aqueous polymeric coagulant pDADMAC is made by several manufacturers and of pre-described weight percent of solids combined with the pre-described aqueous polyaluminum chloride. The first chemical of the invention is mixed in controlled conditions with water to produce a cationic blend polymer and then injected into the waste stream in empirical quantities of 50-700 parts per million (ppm), depending primarily on stream flow rate or strength to cause the coagulation of negatively charged waste particles. The resulting coagulated particles then have sufficient mass and residual cationic charge to react with the subsequent addition of the pre-described, wetted, water dispersed dry anionic flocculent to create an agglomerated particle of sufficient size for removal by mechanical means. The flocculent is injected into the waste stream after a predetermined time to permit the cationic blend to substantially complete the coagulation of the particles by at least two (2) seconds after the injection of the coagulant blend in empirical quantities of 5-50 ppm. This dose of flocculent is critical to not only the flocculation of the coagulated particles but to the later dewatering of the sludge. If either insufficient or excessive flocculent is injected into the wastewater stream, the sludge will not appropriately dewater. The time interval for the coagulant to sufficiently absorb the waste particles prior to injection of the flocculent must be no less than two (2) seconds and no longer than ten (10) minutes. Sufficient passive or active mechanical action must take place between the wastewater and the coagulant as to allow the intimate commingling of the waste particles with the coagulant prior to addition of the flocculent. The dry anionic flocculent must be of a molecular weight as termed in the industry as “very high” and of a charge density of no less than thirty-five percent (35%) but usually around fifty percent (50%). Again depending on wastewater stream strength the preferred range of 7-30 ppm of flocculent is needed to flocculate the coagulated particles to a level where the additional use of other coagulant aids and/or dewatering aids is not necessary. Using this invention, typical sludge generation is reduced 30-80% which equates to 0.2 to 0.6% of sludge being produced of the influent flow and after typical dewatering using a plate and frame press the sludge is reduced another 50%. This compares to other typical treatments utilizing the above described three part systems or others generating 0.8 to 2.5% of the influent flow as sludge. Dewatering characteristics of the sludge in other prior art systems vary from system to system and do cause an additional “body feed” to the sludge in order to achieve dewaterability. The following examples, are set forth to illustrate this invention and render same more understandable but are not intended to limit the scope of the herein disclosed and claimed invention. EXAMPLE ONE Laundry plant #1 with a daily average water usage of 110,000 gallons per day with 50% of the input product being shop towels, mats, ink wipers and other heavy soils was producing 1.1% of their daily wastewater as liquid sludge. The prior existing program being used for industrial pretreatment was a poly(diallydimethylammonium chloride) solution with a dose rate of 200-500 ppm coupled with the use of a six percent bentonite clay fed at the rate of 600 ppm, residence time for each chemical was 15-20 seconds at 125 gpm flow. This created coagulated particles that were then flocculated with a 0.2% polyacrylate flocculent at 6-8 ppm to produce particles able to be floated through mechanical means. The plate and frame press produced dewatered sludge cakes amounting to 135 cubic feet per day. The method of this invention was used to replace the then existing program with a dose rate of 200400 ppm of coagulant using a mix time of approximately 20 seconds, and the application of the flocculent at 20-30 ppm using a mix time of approximately 40 seconds, resulting in floc that was floated through mechanical means. The amount of sludge produced was 0.3% of the influent flow thereby resulting in a dewatered sludge reduction of 66%. Since the application of this invention to plant #1, all required effluent parameters have been compliant with EPA requirements. The effect on the plate and frame dewatering press was a reduction in the final amount of dewatered sludge to 45 cubic feet per day, thus reducing disposal costs of the sludge, as well as substantial savings in treatment chemicals and other additives used in the prior program. EXAMPLE TWO A newly installed dissolved air flotation wastewater system at Plant #2 began utilization of the methods of this invention for chemical treatment of the wastewater at start-up. The volume of water produced by the facility was approximately 70,000 gallons per day and the product mix comprised mostly of heavily grease-laden linen from the food industry. The methods of the invention were applied at 300-600 ppm using a mix time of approximately 15 seconds of coagulant and 25-45 ppm of flocculent using a mix time of approximately 30 seconds, resulting in floc able to be floated through mechanical means, with a resulting sludge production of 0.3% of the influent flow. Since the application of the invention, all required effluent parameters have been compliant with EPA requirements. Treatment in accord with this invention resulted in an influent reduction of 421 ppm of biochemical oxygen demand (BOD) to <5.3 ppm (method EPA 405.1), and 360 ppm to <5.0 ppm oil and grease (method EPA 1664). The effect on the plate and frame dewatering press was to produce only 25 cubic feet of dewatered sludge per day. These examples one and two exemplify the consistent results achievable by this invention. While the dewatered sludge from Plant #2 could have been expected to amount to about 28.6 cubic feet, if the wastewater from the two plants were the same. Also, the newer equipment and other noted differences in the dosage and differing effluents will cause various results while being considered consistent in accord with this invention. EXAMPLE THREE An industrial laundry with an average flow of 80,000 gallons per day treated the wastewater with a pDADMAC coagulant coupled with an aluminum salt (200400 ppm) injected prior to the transfer pump and bentonite clay (600-900 ppm) injected 15 seconds later and sodium acrylate flocculent (7 ppm) 15 seconds down stream. Water was non compliant with a reading of eight (8) on a standard turbidity wedge. Sludge production for the facility was 1100 gallons per day. Filter cakes were not forming inside of the press which necessitated hauling away the liquid sludge. After replacement of the above-described program in accord with this invention at 250 ppm of coagulant being injected prior to the transfer pump and 30 ppm of flocculent being injected at the former clay injection point, sludge was reduced to 350 gallons per day. The plant became compliant with 35+ on a standard turbidity wedge. This new process formed sludge cakes by the press amounting to 7 cubic feet per day, and substantial savings in disposal costs were achieved. Presented in Table 1 are the results of Total Contained Leaching Process (TCLP) data used for determining the long-term hazardous effects of dewatered sludge. The TCLP approximates under laboratory conditions what the sludge will discharge during decomposition into the surrounding environment as known hazardous components. Table 1 is the qualitative analysis of those hazardous components taken from sludge cake utilizing a prior method including bentonite clay (year 2002) and those utilizing the method in accord with this invention (year 2003). TABLE 1 TCLP 2002 TCLP 2003 Before Invention After Invention ANALYTE RESULT UNITS RESULT UNITS METHOD BENZENE <0.001 ppm <0.01 ppm 8260 CARBON TETRACHLORIDE <0.001 ppm <0.01 ppm 8260 CHLOROBENZENE <0.001 ppm <0.01 ppm 8260 CHLOROFORM <0.005 ppm <0.01 ppm 8260 DICHLOROBENZENE, 1,4- <0.005 ppm 0.016 ppm 8260 DICHLOROETHANE, 1,2- <0.005 ppm <0.01 ppm 8260 DICHLOROETHYLENE, 1,1- <0.005 ppm <0.01 ppm 8260 METHYL ETHYL KETONE <0.019 ppm <0.01 ppm 8260 TETRACHLOROETHYLENE <0.017 ppm <0.113 ppm 8260 TRICHLOROETHYLENE <0.005 ppm <0.01 ppm 8260 VINYL CHLORIDE <0.002 ppm <0.001 ppm 8260 CRESOL, M&P <0.1 ppm <0.05 ppm 8270 CRESOL, 0- <0.15 ppm <0.1 ppm 8270 DINITROTOLUENE, 2,4- <0.01 ppm <0.05 ppm 8270 HEXACHLOROBENZENE <0.01 ppm <0.05 ppm 8270 HEXACHLOROBUTADIENE <0.005 ppm <0.05 ppm 8270 HEXACHLOROETHANE <0.005 ppm <0.05 ppm 8270 NITROBENZENE <0.05 ppm <0.05 ppm 8270 PENTACHLOROPHENOL <0.05 ppm <0.05 ppm 8270 PYRIDINE <0.1 ppm <0.1 ppm 8270 TRICHLOROPHENOL, 2,3,5- <0.05 ppm <0.05 ppm 8270 TRICHLOROPHENOL, 2,4,6- <0.05 ppm <0.05 ppm 8270 CHLORDANE <0.01 ppm <0.01 ppm 8270i ENDRIN <0.01 ppm <0.01 ppm 8270i HEPTACHLOR <0.01 ppm <0.008 ppm 8270i HEPTACHLOR EPOXIDE (BETA) <0.008 ppm <0.008 ppm 8270i LINDANE <0.01 ppm <0.01 ppm 8270i METHOXYCHLOR <0.05 ppm <0.01 ppm 8270i TOXAPHENE <0.1 ppm <0.01 ppm 8270i 2,4 D <0.002 ppm <0.02 ppm 8151 2,3,5-TP SILVEX <0.002 ppm <0.02 ppm 8151 ARSENIC, As <0.01 ppm <0.001 ppm 7060 BARIUM, Ba 0.478 ppm <0.1 ppm 7080 CADMIUM, Cd <0.01 ppm <0.01 ppm 7130 LEAD, Pb 0.051 ppm <0.1 ppm 7421 CHROMIUM, Cr 0.049 ppm <0.01 ppm 7190 MERCURY, Hg <0.001 ppm <0.02 ppm 7470 SELENIUM, Se <0.02 ppm <0.02 ppm 7740 SILVER, Ag <0.005 ppm <0.05 ppm 7760 METALS, DIGESTION FOR 1 ea sample 1 ea sample 3030 D SOLIDS 100 percent 100 percent 1311 CORROSIVITY Ph >12.5 or <2 5.1 units 5.9 units 9040 IGNITABILITY >140 .F >140 .F 1010 TOTAL RELEASABLE CYANIDE <0.01 mg/kg <0.009 ppm 9010 TOTAL RELEASABLE SULFIDE <0.5 mg/kg <0.5 ppm 9030 REACTIVITY =0 Negative =0 Negative Exam TCLP SEMI/NON-VOLATILES EXTRACT 1 ea 1 ea 1311 TCLP VOLATILES EXTRACT 1 ea 1 ea 1311 It can be extrapolated from the above two sets of data that neither TCLP has components in sufficient quantities as to categorize the sludge as hazardous under most current regulations for the disposal of sludge. EXAMPLE FOUR An industrial laundry whose wash mix is a majority of heavy soil products treated their wastewater with separately fed injections of 20% solids by weight pDADMAC (200-500 ppm) followed approximately 20 seconds later by a second injection of polyaluminum chloride (400-800) and in approximately 10 seconds an injection of sodium acrylate flocculent to produce EPA and municipal non-compliant effluent (eight on a standard turbidity wedge) and approximately 2200 gallons of sludge with a daily flow of 120,000 gallons of wastewater per day. In order for the facility to dewater the sludge by plate and frame press method, 350 pounds of diatomaceous earth was added as a body feed to produce a sludge cake. After elimination of the previous treatment program and introduction of the methods in accord with this invention, the plant became compliant (35+on a standard turbidity wedge) and the amount of sludge produced was approximately 600 gallons per day. The body feed of Kenite (perlite), needed to produce sludge cake, was eliminated. The coagulant injected at the intake side of the transfer pump was at 150-300 ppm and the flocculent was injected approximately 20 seconds later at 35 ppm. Effluent testing done by a local laboratory showed total petroleum hydrocarbons to be 4 mg/l, which was well within EPA and municipal limits. EXAMPLE FIVE This plant was an industrial laundry with an average daily flow of 70,000 gallons and a mixed product load requiring treatment of the wastewater to meet local limits. An epi-quanternary amine coagulant was being injected prior to the wastewater transfer pump at 500 ppm with an injection of technical grade ferric chloride at 250 ppm into a chemical reaction tank with two minutes detention time at 75 gallons per minute. Then it was gravity fed to a second tank and a sodium acrylate emulsion polymer was fed at 10 ppm. The sludge produced daily was approximately one percent (1%) of the daily flow (700 gallons) and was being hauled for disposal as a liquid. After removal of the above process and incorporating the process in accord with this invention with the coagulant injection point being at the first tank at 400 ppm and the flocculent fed at 25 ppm into the second tank, the effluent quality was clear at 35 on a standard turbidity wedge. Sludge was reduced to 0.5% (350 gallons) of the influent and was hauled for disposal as a liquid because this plant had no plate and frame press. EXAMPLE SIX This plant was an industrial laundry out of compliance on all parameters. At 70,000 gallons per day the facility was producing 1100 gallons of sludge and needed to add as much as 600 pounds of bentonite clay for treatment and as a body feed for sludge dewatering. The treatment scheme utilized at the time was an epi-amine/DADMAC (400-600 ppm) combination coagulant followed by bentonite clay injection (600-1200 ppm) and sodium acrylate flocculent (7-10 ppm). As shown on Table Two, once the prior process was abandoned and the process in accord with this invention was introduced, the plant became compliant with local standards. Injection of the coagulant was made prior to the intake side of the wastewater transfer pump with a five second interval for the injection of the flocculent. Sludge was reduced to 300-350 gallons per day with 25 cubic feet of sludge being produced after plate and frame dewatering. TABLE TWO PARAMETER LIMIT Before Invention After Invention BIOCHEMICAL 300 mg/L 1110 mg/L 120 mg/L OXYGEN DEMAND OIL & GREASE 100 mg/L 187 mg/L 5.2 mg/L (TOTAL pH Acidic <5.5 7.58 9.33 pH Basic >11.5 7.58 9.33 TOTAL SUSPENDED 300 mg/L 1555 mg/L 26 mg/L SOLIDS It is to be noted that under extremely limited conditions, a plant may introduce a small amount of bentonite clay, for example, into the waste stream at approximately two to six seconds after the addition of the coagulant and before the addition of the flocculent, in the herein disclosed method, as a sludge conditioner. Though this is not necessary with this invention, when the waste stream is extremely heavy in oil and grease components (over 1000 ppm), the clay will assist in the dewatering of the sludge. The addition of the clay to be added should be in a much smaller quantity (less than 200 ppm) than used in the prior art methods, i.e., without the use of the present invention. The clay is used for conditioning the sludge only, and not for achieving effluent quality standards, which are attained without clay addition. While the invention has been described with respect to certain specific embodiments, it will be appreciated that many modifications and changes may be made by those skilled in the art without departing from the spirit of the invention. It is intended, therefore, by the appended claims to cover all such modifications and changes as fall within the true spirit and scope of the invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>In the laundry wastewater treatment field of solids/liquid separation, suspended and emulsified solids are removed from water by a variety of processes, including sedimentation, straining, flotation, filtration, coagulation, flocculation, and emulsion breaking among others. Additionally, after solids are removed from the wastewater they must often be dewatered. Liquids treated for solids removal often have as little as several parts per million (ppm) of suspended solids or dispensed oils, or may contain several thousand ppm of suspended solids or oils. Solids being generated as sludge may contain anywhere from 0.1 to 6 weight percent solids prior to dewatering, and from 20 to 50 weight percent solids material after dewatering by a plate and frame press. Solids/liquid separation processes are designed to remove solids from liquids and the more solids generated in the process, the more costly its disposal. While strictly mechanical means have been used to effect solids/liquid separation, the modern methods often rely on mechanical separation techniques that are augmented by synthetic and natural polymeric materials to accelerate the rate at which solids can be removed from water. These processes include the treatment of wastewater with cationic organic and inorganic coagulants that coagulate suspended particulates to form larger particles that then may be brought together by an anionic flocculent to create particles large enough to be removed from the waste stream by mechanical means, i.e., flotation or clarification, and make the effluent suitable for industrial reuse or disposal in compliance with local permit discharge requirements. In the industrial laundry industry, the chemical treatment of wastewater to a typical municipal standard of 100 ppm of oil and grease (EPA method 1664) prior to the introduction of this invention has been: the hydraulic equalization of untreated wastewater followed by the metered flow of the wastewater through a pipe or tanks to provide for retention time for the injection of a variety of chemicals including combinations and individually, both organic and inorganic coagulants and aids, followed by an organic component flocculent to produce coagulation and flocculation. These inorganic components used for coagulation or coagulation aids, typically have simple hydration factors of approximately 6-12 water molecules and may also be used in conjunction with a separate component, i.e. perlite or diatomaceous earth or bentonite clay, to act as a “body builder” to produce sludge so that in down stream processes it may be dewatered. A variety of organic and inorganic coagulants and aids exist throughout the marketplace. Historical data has shown that used in correct combination these chemistries can produce suitable effluent with sludge generation of approximately 1.1 to 2.5% of influent flow, whereas by use of this invention sludge production is reduced to approximately 0.25 to 1.0% of influent flow. Chemical treatment generally refers to the removal of nonsettleable material by coagulation and flocculation. Chemical treatment for wastewater clarification is typically employed when colloidal and microemulsified solids need to be removed so that the total petroleum hydrocarbons (TPH), fat, oil and grease (FOG), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and other contaminants being discharged to a receiving stream need to be minimized. Typically, such treatment comprises using a cationic coagulant with one or more inorganic components, injected in combination or individually, followed by an anionic flocculent. Coagulation is the process of destabilization of the colloid waste particle by causing the coagulant (at 50-1000 ppm) to absorb by means of charge neutralization to form microfloc and impart residual cationic surface charge of the coagulated particles. The second step is to introduce a coagulant aid, i.e., ferric chloride, aluminum sulfate, ferrous sulfate, calcium chloride, polyaluminum chloride, typically at a rate of 75-700 ppm depending on the species, to increase the ability to form a more highly cationic surface that will cause the further adsorption of the coagulated particles onto the surface of an additional chemical, usually bentonite clay, at 200-900 ppm through a “sponge” effect. Flocculation occurs when the highly charged anionic flocculent bridges the previously formed cationic particles. Once neutralized, particles no longer repel each other and can come together to form larger agglomerated solids or sludge, which may then be removed from the water. The third step that is occasionally taken is the addition of sludge thickeners that assist in allowing the sludge to dewater, i.e. perlite, bentonite clay, diatomaceous earth and others. This invention is specifically directed to eliminating the second and/or third steps, i.e., the addition of coagulant aids and or sludge thickeners and a resultant reduction of the formation of sludge by up to 80% compared to previous historically used methods. Clarification chemicals are typically utilized in conjunction with mechanical clarifiers including dissolved air flotation systems (DAFs), induced air flotation systems (IAFs), and settlers for the removal of solids from the treated water. The clarification chemicals coagulate and/or flocculate the suspended solids into larger particles, which can then be removed from the water by gravitational settling, flotation, or other mechanical means. Processes for the preparation of high molecular weight cationic dispersion polymer flocculents are described in U.S. Pat. Nos. 5,006,590 and 4,929,655. High molecular weight, high active polymer cationic solution polymers for water clarification, dewatering and retention and drainage are disclosed in U.S. Pat. No. 6,171,505. | <SOH> BRIEF SUMMARY OF THE INVENTION <EOH>The invention is directed to methods of clarifying industrial wastewater, specifically industrial laundry wastewater, to produce a compliant effluent and a reduction of sludge of between 30%-80%, using a two part system of a pDADMAC/ACH blended coagulant followed by a poly(acrylamide-co-acrylate) flocculent. Furthermore, the sludge produced using this invention will dewater in a typical plate and frame press without the use of any other organic or inorganic compounds added to the waste stream or sludge. This invention pertains to the use of a cationic aqueous solution containing a mostly equal blend of a 50% ratio of approximately a 2-35% concentration of solids by weight of polydiallydimethylammonium chloride (pDADMAC) organic polymer and a combination of epichlorohydrin-quaternaryammonium species where pDADMAC is the major constituent, together with approximately 540% concentration of solids by weight of aluminum chlorohydrate (also known by other names i.e. ACH, also known as partially neutralized polyaluminum chloride) an inorganic compound utilized as a coagulant (along with a combination of other chloride species where ACH is the major constituent) in the chemical demulisification of laundry wastewater to produce catatonic charged particles. The wastewater is cleaned using a medium to high molecular weight medium to very highly charged cationic solution coagulant (polymer) premixed with an inorganic aluminum species as one product, followed by a high to very high molecular weight anionic flocculent, I.e., poly(acrylamide-co-acrylate), (also known herein as sodium acrylate flocculent) with a 35% charge or higher (preferably 50% or higher), added in solution to produce particulate of sufficient size to be removed by physical means without the use of secondary, tertiary, or quaternary coagulation or flocculation aids. The wastewaters, to which this invention is directed, may be produced by the industrial cleaning of products including but not limited to: uniforms, shop towels, ink towels, mats, rugs, bar mops, aprons, coveralls and coats, used to protect personnel from manufacturing or commercial wastes. The creation of the wastewater stream can be through the use of all available commercial equipment that is used for washing the various products. These streams must then be collected in such a way as to promote the batch collection or intermittent or continuous flow of the stream. This collection of wastewater then may be further treated by batch or flow proportion as to allow for the injection and mixing of treatment chemicals by primary coagulation and flocculation only. This invention cleans the wastewater and reduces the sludge generation by as much as 80% from traditional methods of industrial laundry wastewater treatment, resulting in the elimination of additional in-stream and downstream additives. Furthermore, at the proper doses, this invention allows the sludge to be dewatered in a typical plate and frame press or other equipment used for the dewatering of sludge. The specific invention herein relates to the wastewater batch, or the in-stream use of the coagulant polymer compound containing pDADMAC coagulant and ACH injected into the wastewater stream in a diluted or an undiluted form, at any point prior to the sodium acrylate acrylamide flocculent injection with at least a two (2) second interval between the injections. The coagulant must be injected in the correct empirical quantity and given sufficient predetermined time to begin and complete the coagulation of the waste particles and the flocculent must be injected in the correct empirical quantity and given sufficient time to begin and complete the flocculation of the coagulated particles prior to dewatering. The coagulant and flocculent must be injected in sufficient quantity to create the conditions in the sludge that allow for the dewatering of the sludge generated by this process. These injection or dosing ratios are critical to the overall performance of the invention. The dry anionic flocculent is made into any solution strength commonly between 0.05-0.5%, 0.2% being preferred, and injected post coagulant by at least a two (2) second interval and in sufficient empirical quantities as to cause coagulated wastewater to form flocculated waste particles of sufficient size to settle in clarification or rise by flotation, as by dissolved/induced air or other means. The combination of the coagulant and the flocculent in the waste-stream produces a sludge volume 30-80% less than with those previous laundry wastewater treatments which utilize additional treatment chemicals or aids. The process testing of this invention has shown these reductions to be typical of the specific application of the invention disclosed herein. The flocculents of this invention must be of sufficient charge density, molecular weight and added in sufficient quantities, as to aid in all dewatering mechanisms, typically being a plate and frame press often found in typical plants. | 20040419 | 20070109 | 20051020 | 63101.0 | 1 | HRUSKOCI, PETER A | METHOD OF CLARIFYING INDUSTRIAL LAUNDRY WASTEWATER USING CATIONIC DISPERSION POLYMERS AND ANIONIC FLOCCULENT POLYMERS | SMALL | 0 | ACCEPTED | 2,004 |
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10,827,167 | ACCEPTED | Rendering protected digital content within a network of computing devices or the like | Transmitter and receiver computing device are interconnected by a network. The transmitter transmits protected digital content to the receiver in a manner so that the receiver can access the content even though the content is directly licensed to the transmitter and not the receiver. | 1. A method in connection with a first computing device (‘transmitter’) and a second computing device (‘receiver’) interconnected by a network, the transmitter for transmitting protected digital content to the receiver in a manner so that the receiver can access the content, the content being encrypted and decryptable according to a content key (KD), the method comprising: the receiver sending a session request to the transmitter, the session request including an identification of the content to the transmitter, an action to be taken with the content, and a unique identification of the receiver; the transmitter receiving the session request from the receiver, determining from the unique identification of the receiver in the session request that the receiver is in fact registered to the transmitter, obtaining a digital license corresponding to the identified content in the session request, reviewing policy set forth in the license to determine that the license allows the transmitter to provide access to the content to the receiver and also allows the action in the session request, and sending a session response to the receiver, the session response including the policy from the license, the unique identification of the receiver, and the content key (KD) for decrypting the encrypted content, (KD) being protected in a form obtainable by the receiver; the transmitter obtaining the content encrypted according to (KD) to result in (KD(content)), and sending (KD(content) to the receiver; the receiver receiving the session response and (KD(content)), retrieving the policy and the protected content key (KD) for decrypting the encrypted content from the session response, confirming that the policy allows the receiver to render the content, obtaining the content key (KD), applying (KD) to (KD(content)) to reveal the content, and then in fact rendering the content in accordance with the policy. 2. The method of claim 1 comprising: the transmitter in conjunction with sending the session response also storing at least a portion of the session request and at least a portion of the session response in a transmitter session store; the receiver receiving the session response from the transmitter and storing at least a portion of the session response in a receiver session store; the receiver retrieving at least a portion of the session response from the receiver session store, and sending a transfer request to the transmitter based on the session response; and the transmitter receiving the transfer request and retrieving the at least a portion of the session request and at least a portion of the session response from the transmitter store based on the transfer request, retrieving from the retrieved at least a portion of the session request and at least a portion of the session response the identification of the content, obtaining the content encrypted according to (KD) to result in (KD(content)), and sending a transfer response to the receiver including (KD(content)). 3. The method of claim 1 comprising the receiver sending the session request further including a version number of a revocation list of the receiver (V-RL-R), and the transmitter sending the session response further including a version number of a revocation list of the transmitter (V-RL-X), the method further comprising the receiver determining that (V-RL-R) is more current than (V-RL-X) and sending the revocation list thereof to the transmitter. 4. The method of claim 1 comprising the receiver sending the session request further including a version number of a revocation list of the receiver (V-RL-R), and the transmitter determining that a version number of a revocation list thereof (V-RL-X) is more current than (V-RL-R) and sending the revocation list thereof to the receiver. 5. The method of claim 1 comprising the receiver sending a session request to the transmitter including a public key of the receiver (PU-R) and the transmitter sending a session response to the receiver including the content key (KD) for decrypting the content encrypted according to (PU-R). 6. The method of claim 1 comprising the receiver sending a session request to the transmitter including a public key of the receiver (PU-R) and the transmitter sending a session response to the receiver including a seed from which the content key (KD) for decrypting the content may be derived, the seed being encrypted according to (PU-R). 7. The method of claim 1 wherein the transmitter has a public-private key pair (PU-X, PR-X), and further comprising the transmitter obtaining the content key (KD) from the license as (PU-X(KD)), applying (PR-X) to (PU-X(KD)) to result in (KD), and then re-encrypting (KD) according to a public key of the receiver (PU-R) to result in (PU-R(KD)), the receiver decrypting the content key by applying a private key (PR-R) corresponding to (PU-R) to (PU-R(KD)) to result in (KD). 8. The method of claim 1 comprising the transmitter sending a session response to the receiver further including a signature/MAC generated based on such session response, the signature/MAC binding the policy to the session response. 9. The method of claim 8 comprising the transmitter sending a session response to the receiver including a signature/MAC based on a symmetric integrity key (KI), the session response further including (KI) encrypted according to a public key of the receiver (PU-R) to result in (PU-R(KI)), the method also comprising the receiver receiving the session response from the transmitter, retrieving (PU-R(KI)) therefrom, applying a private key (PR-R) corresponding to (PU-R) to (PU-R(KI)) to result in the (KI), and verifying the signature/MAC of the session response based on (KI). 10. The method of claim 8 comprising the transmitter sending a session response to the receiver including a signature/MAC based on a symmetric integrity key (KI) derivable from a seed, the session response further including the seed protected according to a public key of the receiver (PU-R) to result in (PU-R(seed)), the method also comprising the receiver receiving the session response from the transmitter, retrieving (PU-R(seed)) therefrom, applying a private key (PR-R) corresponding to (PU-R) to (PU-R(seed)) to result in the seed, deriving (KI) from the seed, and verifying the signature/MAC of the session response based on (KI). 11. The method of claim 1 further comprising the receiver registering with the transmitter by: the receiver sending a registration request to the transmitter, the registration request including the unique identification of the receiver; the transmitter validating the registration request; the transmitter sending a registration response to the receiver, the registration response including a registration ID generated by the transmitter to identify the registration response, and the unique identification of the receiver; the receiver sending a port address of a port thereof and the registration ID to the transmitter; the transmitter sending a proximity message to the receiver by way of the sent port address and concurrently noting a start time; the receiver upon receiving the proximity message at the port address thereof employing at least a portion of the registration response and the proximity message to generate a proximity value and sending a proximity response with the proximity value to the transmitter; and the transmitter receiving the proximity response with the proximity value from the receiver and concurrently noting an end time, verifying the proximity value based on the first and second nonces, calculating from the noted start and end times an elapsed time, comparing the elapsed time to a predetermined threshold value, deciding from the comparison that the receiver satisfies a proximity requirement, and registering the receiver as being able to access content from such transmitter. 12. The method of claim 11 comprising the receiver sending a registration request to the transmitter including a digital certificate provided to the receiver by an appropriate certifying authority, the certificate including therein a public key of the receiver (PU-R) and a digital signature, the method also comprising the transmitter validating the certificate and verifying with reference to a revocation list that the certificate has not been revoked. 13. The method of claim 11 comprising the receiver sending a registration request to the transmitter including a device ID of the receiver. 14. The method of claim 11 comprising the receiver sending a registration request to the transmitter including a public key of the receiver (PU-R), and comprising the transmitter encrypting at least a portion of the registration response by (PU-R) and the receiver decrypting the registration response by application of a private key (PR-R) corresponding to (PU-R). 15. The method of claim 11 comprising: the transmitter sending the registration response including a first nonce to the receiver; the transmitter sending the proximity message with a second nonce to the receiver by way of the sent port address and concurrently noting the start time; the receiver upon receiving the proximity message at the port address thereof employing the sent first and second nonces to generate the proximity value and sending the proximity response with the proximity value and the registration ID to the transmitter. 16. The method of claim 15 comprising the receiver generating a proximity value by employing the first nonce as a cryptographic key to perform an encryption of the second nonce and thus result in an encrypted value. 17. The method of claim 15 comprising the receiver generating a proximity value by employing the first nonce as a cryptographic key to perform a hash over the second nonce and thus result in a hash value. 18. The method of claim 15 comprising the receiver generating a proximity value by performing a hash over the first and second nonces to result in a hash value. 19. The method of claim 11 comprising the transmitter registering the receiver by placing the unique identification of the receiver in a registry list, and determining from the unique identification of the receiver in the session request with reference to the registry list that the receiver is in fact registered to the transmitter. 20. The method of claim 11 comprising the transmitter periodically requiring the receiver to re-register by re-sending a registration request to the transmitter. | TECHNICAL FIELD The present invention relates to an architecture and method for allowing digital content with a corresponding digital license tied to a particular computing device within a network or the like to be rendered by another computing device within the network. More particularly, the present invention relates to such an architecture and method whereby the computing devices within the network negotiate access to the content as between the computing devices. BACKGROUND OF THE INVENTION As is known, and referring now to FIG. 1, a rights management (RM) and enforcement system is highly desirable in connection with digital content 12 such as digital audio, digital video, digital text, digital data, digital multimedia, etc., where such digital content 12 is to be distributed to users. Upon being received by the user, such user renders or ‘plays’ the digital content with the aid of an appropriate rendering device such as a media player on a personal computer 14, a portable playback device or the like. Typically, a content owner distributing such digital content 12 wishes to restrict what the user can do with such distributed digital content 12. For example, the content owner may wish to restrict the user from copying and re-distributing such content 12 to a second user, or may wish to allow distributed digital content 12 to be played only a limited number of times, only for a certain total time, only on a certain type of machine, only on a certain type of media player, only by a certain type of user, etc. However, after distribution has occurred, such content owner has very little if any control over the digital content 12. An RM system 10, then, allows the controlled rendering or playing of arbitrary forms of digital content 12, where such control is flexible and definable by the content owner of such digital content. Typically, content 12 is distributed to the user in the form of a package 13 by way of any appropriate distribution channel. The digital content package 13 as distributed may include the digital content 12 encrypted with a symmetric encryption/decryption key (KD), (i.e., (KD(CONTENT))), as well as other information identifying the content, how to acquire a license for such content, etc. The trust-based RM system 10 allows an owner of digital content 12 to specify rules that must be satisfied before such digital content 12 is allowed to be rendered. Such rules can include the aforementioned requirements and/or others, and may be embodied within a digital license 16 that the user/user's computing device 14 (hereinafter, such terms are interchangeable unless circumstances require otherwise) must obtain from the content owner or an agent thereof, or such rules may already be attached to the content 12. Such license 16 may for example include the decryption key (KD) for decrypting the digital content 12, perhaps encrypted according to another key decryptable by the user's computing device or other playback device. The content owner for a piece of digital content 12 would prefer not to distribute the content 12 to the user unless such owner can trust that the user will abide by the rules specified by such content owner in the license 16 or elsewhere. Preferably, then, the user's computing device 14 or other playback device is provided with a trusted component or mechanism 18 that will not render the digital content 12 except according to such rules. The trusted component 18 typically has an evaluator 20 that reviews the rules, and determines based on the reviewed rules whether the requesting user has the right to render the requested digital content 12 in the manner sought, among other things. As should be understood, the evaluator 20 is trusted in the RM system 10 to carry out the wishes of the owner of the digital content 12 according to the rules, and the user should not be able to easily alter such trusted component 18 and/or the evaluator 20 for any purpose, nefarious or otherwise. As should be understood, the rules for rendering the content 12 can specify whether the user has rights to so render based on any of several factors, including who the user is, where the user is located, what type of computing device 14 or other playback device the user is using, what rendering application is calling the RM system 10, the date, the time, etc. In addition, the rules may limit rendering to a pre-determined number of plays, or pre-determined play time, for example. The rules may be specified according to any appropriate language and syntax. For example, the language may simply specify attributes and values that must be satisfied (DATE must be later than X, e.g.), or may require the performance of functions according to a specified script (IF DATE greater than X, THEN DO . . . , e.g.). Upon the evaluator 20 determining that the user satisfies the rules, the digital content 12 can then be rendered. In particular, to render the content 12, the decryption key (KD) is obtained from a pre-defined source and is applied to (KD(CONTENT)) from the content package 13 to result in the actual content 12, and the actual content 12 is then in fact rendered. In an RM system 10, content 12 is packaged for use by a user by encrypting such content 12 and associating a set of rules with the content 12, whereby the content 12 can be rendered only in accordance with the rules. Because the content 12 can only be rendered in accordance with the rules, then, the content 12 may be freely distributed. Typically, the content 12 is encrypted according to a symmetric key such as the aforementioned key (KD) to result in (KD(content)), and (KD(content)) therefore is also decrypted according to (KD) to result in the content 12. Such (KD) is in turn included within the license 16 corresponding to the content 12. Oftentimes, such (KD) is encrypted according to a public key such as the public key of the computing device 14 (PU-C) upon which the content 12 is to be rendered, resulting in (PU-C(KD)). Note, though, that other public keys may be employed, such as for example a public key of a user, a public key of a group of which the user is a member, etc. Thus, and presuming the public key is (PU-C), the license 16 with (PU-C(KD)) is tied to and may only be used in connection with such computing device 14 inasmuch as only such computing device 14 should have access to the private key (PR-C) corresponding to (PU-C). As should be appreciated, such (PR-C) is necessary to decrypt (PU-C(KD)) to obtain (KD), and should be closely held by such computing device 14. It is to be appreciated that a user at times may have a plurality of computing devices 14 that are networked or otherwise inter-connected in a network 17 or the like. In such a situation, it may be the case that the user may obtain a license 16 to render a corresponding piece of content 12, where the license 16 includes (KD) for the piece of content 12 encrypted according to the public key of a first computing device 14 (PU-C1) to result in (PU-C1(KD)), and thus such license 16 is tied to such first computing device 14. Moreover, in such a situation, it may further be the case that the user wishes to render the content 12 on a second computing device 14 that is in the network 17 with the first computing device 14. However, and crucially, such second computing device 14 does not have access to the private key of the first computing device 14 (PR-C1), as such first computing device 14 should be loathe to reveal such (PR-C1) to such second computing device 14. Instead, such second computing device 14 only has access to the private key of such second computing device 14 (PR-C2), which of course cannot be applied to (PU-C1(KD)) to reveal such (KD). Thus, without additional architecture, the second computing device 14 is unable to obtain (KD) from (PU-C1(KD)) and thereby decrypt (KD(content)), as is necessary to render such content 12. Such inability exists even though the user can render the content 12 by way of the first computing device 14, the second computing device 14 is in the network 17 with the first computing device 14, and both the first and second computing devices 14 are under the control of the same user. Accordingly, a need exists for an architecture and method that allow content 12 with a corresponding license 16 tied to one computing device 14 in a network 17 or the like to be rendered by any other appropriate computing device 14 in the network 17, presuming the license 16 so allows. In particular, a need exists for a method of negotiating access to the content 12 as between the computing devices 14 in the network 17. SUMMARY OF THE INVENTION The aforementioned needs are satisfied at least in part by the present invention in which a method is provided in connection with a first computing device (‘transmitter’) and a second computing device (‘receiver’) interconnected by a network, where the transmitter transmits protected digital content to the receiver in a manner so that the receiver can access the content. The content is encrypted and decryptable according to a content key (KD). In the method, the receiver sends a session request to the transmitter, where the session request includes an identification of the content to the transmitter, an action to be taken with the content, and a unique identification of the receiver. The transmitter receives the session request from the receiver, determines from the unique identification of the receiver in the session request that the receiver is in fact registered to the transmitter, obtains a digital license corresponding to the identified content in the session request, reviews policy set forth in the license to determine that the license allows the transmitter to provide access to the content to the receiver and also allows the action in the session request, and sends a session response to the receiver, where the session response includes the policy from the license, the unique identification of the receiver, and the content key (KD) for decrypting the encrypted content, (KD) being protected in a form obtainable by the receiver. The transmitter obtains the content encrypted according to (KD) to result in (KD(content)), and sends (KD(content) to the-receiver. The receiver receives the session response and (KD(content)), retrieves the policy and the protected content key (KD) for decrypting the encrypted content from the session response, confirms that the policy allows the receiver to render the content, obtains the content key (KD), applies (KD) to (KD(content)) to reveal the content, and then in fact renders the content in accordance with the policy. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing summary, as well as the following detailed description of the embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. As should be understood, however, the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings: FIG. 1 is a block diagram showing an enforcement architecture of an example of a trust-based system; FIG. 2 is a block diagram representing a general purpose computer system in which aspects of the present invention and/or portions thereof may be incorporated; FIG. 3 is a block diagram showing the transmitter and receiver of FIG. 1; and FIGS. 4, 5, and 6 are flow diagrams showing key steps performed by the transmitter and receiver of FIG. 3 when registering the receiver to the transmitter (FIG. 4), establishing a session between the receiver and transmitter (FIG. 5), and transferring content from the transmitter to the receiver (FIG. 6) in accordance with one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION Computer Environment FIG. 1 and the following discussion are intended to provide a brief general description of a suitable computing environment in which the present invention and/or portions thereof may be implemented. Although not required, the invention is described in the general context of computer-executable instructions, such as program modules, being executed by a computer, such as a client workstation or a server. Generally, program modules include routines, programs, objects, components, data structures, and the like that perform particular tasks or implement particular abstract data types. Moreover, it should be appreciated that the invention and/or portions thereof may be practiced with other computer system configurations, including hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like. The invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices. As shown in FIG. 2, an exemplary general purpose computing system includes a conventional personal computer 120 or the like, including a processing unit 121, a system memory 122, and a system bus 123 that couples various system components including the system memory to the processing unit 121. The system bus 123 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. The system memory includes read-only memory (ROM) 124 and random access memory (RAM) 125. A basic input/output system 126 (BIOS), containing the basic routines that help to transfer information between elements within the personal computer 120, such as during start-up, is stored in ROM 124. The personal computer 120 may further include a hard disk drive 127 for reading from and writing to a hard disk, a magnetic disk drive 128 for reading from or writing to a removable magnetic disk 129, and an optical disk drive 130 for reading from or writing to a removable optical disk 131 such as a CD-ROM or other optical media. The hard disk drive 127, magnetic disk drive 128, and optical disk drive 130 are connected to the system bus 123 by a hard disk drive interface 132, a magnetic disk drive interface 133, and an optical drive interface 134, respectively. The drives and their associated computer-readable media provide non-volatile storage of computer readable instructions, data structures, program modules and other data for the personal computer 120. Although the exemplary environment described herein employs a hard disk 127, a removable magnetic disk 129, and a removable optical disk 131, it should be appreciated that other types of computer readable media which can store data that is accessible by a computer may also be used in the exemplary operating environment. Such other types of media include a magnetic cassette, a flash memory card, a digital video disk, a Bernoulli cartridge, a random access memory (RAM), a read-only memory (ROM), and the like. A number of program modules may be stored on the hard disk, magnetic disk 129, optical disk 131, ROM 124 or RAM 125, including an operating system 135, one or more application programs 136, other program modules 137 and program data 138. A user may enter commands and information into the personal computer 120 through input devices such as a keyboard 140 and pointing device 142. Other input devices (not shown) may include a microphone, joystick, game pad, satellite disk, scanner, or the like. These and other input devices are often connected to the processing unit 121 through a serial port interface 146 that is coupled to the system bus, but may be connected by other interfaces, such as a parallel port, game port, or universal serial bus (USB). A monitor 147 or other type of display device is also connected to the system bus 123 via an interface, such as a video adapter 148. In addition to the monitor 147, a personal computer typically includes other peripheral output devices (not shown), such as speakers and printers. The exemplary system of FIG. 2 also includes a host adapter 155, a Small Computer System Interface (SCSI) bus 156, and an external storage device 162 connected to the SCSI bus 156. The personal computer 120 may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 149. The remote computer 149 may be another personal computer, a server, a router, a network PC, a peer device, or other common network node, and typically includes many or all of the elements described above relative to the personal computer 120, although only a memory storage device 150 has been illustrated in FIG. 2. The logical connections depicted in FIG. 2 include a local area network (LAN) 151 and a wide area network (WAN) 152. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets, and the Internet. When used in a LAN networking environment, the personal computer 120 is connected to the LAN 151 through a network interface or adapter 153. When used in a WAN networking environment, the personal computer 120 typically includes a modem 154 or other means for establishing communications over the wide area network 152, such as the Internet. The modem 154, which may be internal or external, is connected to the system bus 123 via the serial port interface 146. In a networked environment, program modules depicted relative to the personal computer 120, or portions thereof, may be stored in the remote memory storage device. It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used. Rendering Content 12 in Networked Computing Devices 14 Content protection denotes a spectrum of methods and technologies for protecting digital content 12 such that such content 12 cannot be used in a manner inconsistent with the wishes of the content owner and/or provider. Methods include copy protection (CP), link protection (LP), conditional access (CA), rights management (RM), and digital rights management (DRM), among other. The Base of any content protection system is that only a trusted application that ensures proper adherence to the implicit and/or explicit rules for use of protected content 12 can access same in an unprotected form. Typically, content 12 is protected by being encrypted in some way, where only trusted parties are able to decrypt same. Copy protection, in the strictest sense, specifically applies to content 12 residing in a storage device, whereas link protection applies to content 12 flowing between applications/devices over a transmission medium. Conditional access can be thought of as a more sophisticated form of link protection, where premium programs, channels and/or movies are encrypted in transit. Only subscribers who have paid for access to such content 12 are provided with the keys necessary to decrypt same. Digital Rights Management is an extensible architecture where the rules regarding sanctioned use of a particular piece of content 12 are explicit and bound to or associated with the content 12 itself. DRM mechanisms can support richer and more expressive rules than other methods while providing greater control and flexibility at the level of individual pieces of content or even sub-components of that content. An example of a Digital Rights Management system is set forth in U.S. patent application Ser. No. 09/290,363, filed Apr. 12, 1999 and U.S. Provisional Application No. 60/126,614, filed Mar. 27, 1999 each of which is hereby incorporated by reference in its entirety. Rights Management is a form of DRM that is organizationally based in that content 12 can be protected to be accessible only within an organization or a subset thereof. An example of a Rights Management system is set forth in U.S. patent applications Ser. Nos. 10/185,527, 10/185,278, and 10/185,511, each filed on Jun. 28, 2002 and hereby incorporated by reference in its entirety. In the present invention, content 12 with a corresponding license 16 tied to a first computing device 14 in a network 17 may be accessed by way of second computing device 14 in the network 17, provided of course that the license 16 so allows. Typically, the network 17 is a home or business network 17 that is restricted to a relatively modest number of users, although it is to be appreciated that the network 17 may be any appropriate network of interconnected computing devices 14 without departing from the spirit and scope of the present invention. For example, the network 17 may be as simple as a cable interconnecting the computing devices 14. Note, though, that an owner of content 12 may wish to restrict access of such content 12 over a relatively large network 17 such as for example the Internet, and may even wish to restrict access of such content 12 over any network 17 whatsoever, such as for example when such access may subvert the owner receiving a license fee for a license 16 for the content 12, or if such access could increase the likelihood that the content 12 would be stolen by a nefarious entity. The computing devices 14 in the network 17 may be any appropriate computing devices 14 without departing from the spirit and scope of the present invention. Typically, at least some computing devices 14 in the network are personal computing devices such as laptop or desktop computers, and it is to be recognized that at least some of such computing devices 14 may also be portable computing devices that are connected to the network 17 only to download content for rendering thereon, rendering computing devices 14 such as printers, monitors, speakers, etc., portable memory devices, and the like. The present invention may be employed, then, to extend the reach of RM-protected content 12 to a portable electronic player device 14 connected to a computer 14 over a home network 17. Significantly, the present invention enables access to protected content 12 while enforcing the rights specified by the content owner in a license 16 corresponding thereto. With the present invention, then, a digital media store may centrally store a library of content on a personal computer 14 while still allowing remote access from points throughout a limited area such as a home, even if the device 14 remotely accessing the content 12 does not acquire a license 16 tied thereto for the content 12. With the present invention, content 12 is safely transmitted over a network 17 while preserving the rights of the owner of such content 12. In one embodiment of the present invention, the method of delivering the content 12 from a first, transmitting computing device 14 (hereinafter, ‘transmitter’) to a second, receiving computing device 14 (hereinafter, ‘receiver’) is agnostic to the actual protocols used for transporting the content 12. Thus, the particular way in which the transmitter and receiver communicate is irrelevant to the method. In addition, in one embodiment of the present invention, the method of delivering the content 12 from the transmitter to the receiver is agnostic to the format of the content 12. Thus, the any particular type of content 12 may be sent to from the transmitter to the receiver by way of such method. Turning now to FIG. 3, it is seen that in one embodiment of the present invention, a transmitter 14x transmits content 12 to a receiver 14r over an interconnecting network 17, where the transmitter already has such content 12 and a license 16 corresponding thereto, and where the transmitter 14x has a public-private key pair (PU-X, PR-X) associated therewith and the receiver 14r likewise has a public-private key pair (PU-R, PR-R) associated therewith. As shown, the content 12 is in the form of a content package 13 with the content 12 encrypted according to a symmetric content key (KD) to result in (KD(content)), and the license 16 includes a description of rights and conditions (hereinafter, ‘policy’), perhaps including whether the receiver 14r may access the content 12 by way of the transmitter 14x and the network 17, and also includes the content key (KD) encrypted according to the private key of the transmitter 14x (PU-X) to result in (PU-X(KD)). Note that although the present invention is disclosed primarily in terms of a symmetric content key (KD) and public-private key pairs for the transmitter 14x and the receiver 14r, other encryption arrangements may also be employed without departing from the spirit and scope of such present invention. Turning now to FIGS. 4-6, to arrange for the receiver 14r to access the content 12 by way of the transmitter 14x and network 17, and in one embodiment of the present invention, methods are employed to register the receiver 14r to the transmitter 14x (FIG. 4), establish a session between the transmitter 14x and receiver 14r (FIG. 5), and transfer the content 12 from the transmitter 14x to the receiver 14r (FIG. 6), whereby the receiver 14r can render the transferred content 12 according to the terms of the license 16 corresponding thereto. In particular, and referring now to FIG. 4, in one embodiment of the present invention, the receiver 14r is registered to the transmitter 14x upon the receiver 14r sending a registration request to the transmitter 14x by way of the interconnecting network 17 (step 401). As should be appreciated, the registration request should include a unique identification of the receiver 14r, and accordingly such unique identification is at least partially achieved by including with the registration request a digital certificate 22 provided to the receiver 14r by an appropriate certifying authority. As may also be appreciated, the digital certificate 22 includes therein the public key of the receiver 14r (PU-R) and is digitally signed by the certifying authority, and thus the digital signature of the certificate 22 may be verified by appropriate application of (PU-R) thereto. As may further be appreciated, the certificate 22 may include a chain of certificates leading back to the certifying authority, whereby the transmitter 14x with knowledge of a verifying public key corresponding to the certifying authority may verify the chain of certificates to ascertain that the certificate 22 did indeed originate from the certifying authority. In at least some instances, and as is known, a receiver 14r may share a certificate 22 with other similar devices, especially if the receiver 14r is relatively simple or was otherwise designed as such by the manufacturer thereof. In anticipation of such a situation, and to ensure that the registration request does indeed include a unique identification of the receiver 14r, the registration request from the receiver 14r also includes a device ID 24 of such receiver 14r, whereby the device ID 24 of such receiver 14r is different from the device ID 24 of every other similar device that could share a common certificate 22 with such receiver 14r. Thus, between the certificate 22 and the device ID 24, the receiver 14r is uniquely identified in the registration request sent to the transmitter 14x. Note that while the device ID 24 may be dispensed with in the case where a certificate 22 is unique to a receiver 14r, the transmitter 14x and/or the receiver 14r may not always be capable of ascertaining whether such certificate 22 is indeed unique to the receiver 14r, and thus it may be considered good practice to always require a device ID 24 with a certificate 22 in a registration request. At any rate, upon receiving the registration request, the transmitter 14x validates the certificate 22 thereof (step 403), and in particular verifies that the certificate 22 can be traced back by way of the accompanying chain of certificates to a certifying authority known to and approved by such transmitter 14x, and also verifies with reference to an appropriate revocation list 26 thereof that the certificate 22 has not been revoked. Essentially, then, the transmitter 14x will impart trust to the receiver 14r to properly handle received content 12, at least in part, if the receiver 14r owns a non-revoked certificate 22 derived from an approved certifying authority. Presuming the transmitter 14x finds a non-revoked and approved certificate 22 in the registration request, the transmitter 14x may decide without further ado to in fact register the receiver 14r as being able to access content 12 by way of such transmitter 14x and the network 17. However, in one embodiment of the present invention, the transmitter 14x prior to registering the receiver 14r also ensures that the receiver 14r is within a certain proximity to the transmitter 14x, measured either as a function of distance, time, or otherwise. As may be appreciated, such a proximity requirement may be employed to prevent a situation where a wide-area network 17 is employed to register a receiver 14r to a transmitter 14x. Such use of a wide-areas network 17 is to be discouraged inasmuch as any receiver 14r anywhere in the world should not be allowed to register with the transmitter 14x. Otherwise, one or more users could create a broad network 17 of receivers 14r registered to the transmitter 14x and thereby subvert an implicit goal of restricting access to content 12 by way of the network 17 to one user or possibly a well-defined group of related users. At any rate, to enforce such a proximity requirement, and still referring to FIG. 4, the transmitter 14x sends a registration response to the requesting receiver 14r by way of the interconnecting network 17 (step 405). In one embodiment of the present invention, the registration response includes a registration ID generated by the transmitter 14x to identify the registration request, at least one of the device ID 24 and (PU-R) of the receiver 14r as obtained from the registration request, and a first nonce to be employed as will be set forth in more detail below. As should be appreciated, the first nonce is essentially a random value. To prevent any nefarious entity from browsing such information, the registration response or at least a portion thereof may be encrypted in a manner decryptable by the receiver 14r, such as for example by (PU-R) thereof, although another cryptographic key may be employed without departing from the spirit and scope of the present invention. Upon receiving the registration response, the receiver 14r decrypts same and ensures that the at least one of the device ID 24 and (PU-R) are that of such receiver 14r (step 407), and if so the receiver 14r sends an address of a port thereof along with the registration ID to the transmitter 14x by way of the interconnecting network 17 (step 409). As will be seen below, the port may be any appropriate port of the receiver 14r, and should be selected primarily based on how quickly the transmitter 14x can access the receiver 14r thereby for the reason that the proximity requirement is satisfied primarily based on how quickly the transmitter 14x sends a proximity message to the receiver 14r and receives a proximity response therefrom. With the port address as received from the receiver 14r, the transmitter 14x performs a proximity test by sending the proximity message with a second nonce to the receiver 14r by way of the network 17 and the received port address of such receiver 14r (step 411). The second nonce is to be employed as will be set forth in more detail below. The second nonce is essentially a random value. Concurrently with step 411, the transmitter 14x notes a start time at which the proximity message with the second nonce is sent. The receiver 14r receives the proximity message with the second nonce from the transmitter 14x by way of the network 17 and the port address of such receiver 14r, and thereafter employs the received first and second nonces to produce a proximity value (step 413), and then sends the proximity response with the proximity value back to the transmitter 14x by way of the network 17 (step 415). Note that the proximity value may be any value based on the first and second nonces without departing from the spirit and scope of the present invention. For example, the proximity value may be a hash of the first and second nonces. Likewise, the proximity value may be achieved by employing the first nonce as a cryptographic key to perform a hash over the second nonce. Note here that the performed hashes may be any appropriate performed hashes without departing from the spirit and scope of the present invention. Performing a hash is known or should be apparent to the relevant public and therefore need not be set forth herein in any detail. At any rate, the transmitter 14x receives the proximity response with the proximity value from the receiver 14r by way of the network 17 (step 417), and concurrently therewith notes an end time at which the proximity value is received, thus ending the proximity test. Thereafter, the transmitter 14x verifies the proximity value based on knowledge of the first and second nonces (step 419). Presuming the proximity value verifies, the transmitter 14x then calculates from the noted start and end times an elapsed time and compares same to a predetermined threshold value (step 421), and decides from the comparison whether the receiver 14r is close enough to satisfy the proximity requirement (step 423). If so, the transmitter 14x registers the receiver 14r as being able to access content 12 from such transmitter 14x by way of the interconnecting network 17 (step 425). As may be appreciated, the elapsed time should at least roughly correspond to how far away the receiver 14r is from the transmitter 14x, and thus the elapsed time from the proximity test should be less than the threshold value to satisfy the proximity requirement. Such a threshold value may be determined for the transmitter 14x on a case-by-case basis, may be set to a particular value by some external source, may be set to a particular value by a requirement of a license 16, or the like. To evidence that the receiver 14r is in fact registered to the transmitter 14x, the transmitter 14x may maintain a registry list 28 including an identification of the receiver 14r such as the certificate 22 with (PU-R) therein and/or the device ID 24 from the receiver 14r. Of course, such registry list 28 may also have other appropriate information therein without departing from the spirit and scope of the present invention. Once registered to the transmitter 14x, the receiver 14r may remain registered indefinitely. Alternatively, the transmitter 14x may periodically require the receiver 14r to re-register in accordance with the method shown in FIG. 4. Such re-registration may for example be required after a certain time period, after a certain number of pieces of content 12 are accessed, after the trusted component 18 of the receiver 14r is upgraded, or the like. Such information may of course be recorded in an appropriate manner within the registry list 28. Among other things, periodically re-registering the receiver 14r ensures that the receiver 14r still satisfies the proximity requirement. The transmitter 14x can theoretically register any number of receivers 14r thereto. However, in one embodiment of the present invention, the transmitter 14x has a predefined maximum number of receivers 14r that can be registered thereto. Likewise, in one embodiment of the present invention, the transmitter 14x has a predefined number of receivers 14r that can concurrently access content 12 therefrom. Again, such information may of course be recorded in an appropriate manner within the registry list 28. Thus, a user cannot subvert an implicit goal of restricting access to content 12 to a limited number of receivers 14r by way of the network 17. As should be appreciated, once the maximum number of receivers 14r is reached, the transmitter 14x in the former case can no longer register new receivers 14r thereto unless an existing registered receiver 14r is appropriately de-registered, and in the latter case can no longer allow access to content 12 to a new receiver 14r unless an existing accessing receiver 14r is appropriately de-coupled. Presuming now that the receiver 14r is registered to the transmitter 14x, and as was alluded to above, the receiver 14r in one embodiment of the present invention must establish a session with the transmitter 14x to access content 12 therefrom. Referring now to FIG. 5, in one embodiment of the present invention, the transmitter 14x and receiver 14r establish a session therebetween upon the receiver 14r sending a session request to the transmitter 14x by way of the network 17 (step 501). In particular, the session request identifies the content 12 to the transmitter 14x and an action to be taken therewith, and also includes a session ID-R generated by the receiver 14r to identify the session request, the certificate 22 of the receiver 14r with (PU-R) therein, and the device ID 24 thereof. In addition, it may be the case that the session request includes a version number of a revocation list 26 of the receiver 14r (V-RL-R). As may be appreciated, inasmuch as the transmitter 14x has such a revocation list 26 for verifying that a certificate 22 from a receiver 22 is not revoked as at step 403 of FIG. 4, the receiver 14r may also have such a revocation list 26 in the case where the receiver 14r itself acts as a transmitter 14x with respect to another receiver 14r. Thus, the receiver 14r when functioning as a transmitter 14x may itself have need for and refer to such a revocation list 26. As may also be appreciated, and as set forth in more detail below, the version number of the revocation list 26 of the receiver 14r (V-RL-R) is compared to the version number of the revocation list 26 of the transmitter 14x (V-RL-X), and if (V-RL-X) is more current than (V-RL-R) and is properly signed by the issuing certification authority, the transmitter 14x may send the revocation list 26 thereof to the receiver 14r. Optionally, if (V-RL-R) is more current than (V-RL-X), the receiver 14r may send the revocation list 26 thereof to the transmitter 14x. Thus, the revocation lists 26 on each of the transmitter 14x and the receiver 14r may be updated as necessary. In response to the session request from the receiver 14r, the transmitter 14x first determines based on the certificate 22 with (PU-R) therein and/or the device ID 24 from the session request and with reference to the registry list 28 thereof that the receiver 14r is in fact registered to the transmitter 14x (step 503). Thereafter, the transmitter 14x obtains the license 16 corresponding to the content 12 identified in the session request and reviews the policy set forth therein (step 505). Presuming that such policy allows the transmitter 14x to provide the content 12 to the receiver 14r by way of the network 17, and also allows the action identified in the session request, the transmitter 14x composes and sends to the receiver 14r by way of the network 17 a session response (step 507) including the policy as obtained from and based on the license 16, the device ID 24 of the receiver 14r as obtained from the session request, the session ID-R from the receiver as obtained from the request, and the content key (KD) for decrypting the content 12 encrypted according to the public key of the receiver 14r (PU-R) as obtained from the certificate 22 sent with the session request. Alternatively, rather than sending (KD) encrypted by (PU-R), it may be the case that the transmitter 14x and receiver 14r both share knowledge of how to derive (KD) from a seed, whereby the seed is sent in the session response encrypted by (PU-R). The content key (KD) for decrypting the content 12 if not derived from a seed may be obtained by the transmitter 14x from the corresponding license 16 as (PU-X(KD)), decrypted by the transmitter 14x by application of the corresponding (PR-X), and then re-encrypted according to (PU-R) to result in (PU-R(KD)); or such. Alternatively, the transmitter 14x may decide to obtain such (KD), decrypt the content 12 based thereon and re-encrypt according to another (KD), and then encrypt the another (KD) according to (PU-R) to result in (PU-R(KD)). Also alternatively, it may be that the content 12 is not initially encrypted at the transmitter 14x, in which case the transmitter selects a (KD), encrypts the content 12 according to such (KD), and then encrypts the selected (KD) according to (PU-R) to result in (PU-R(KD)). Likewise, the content key (KD) for decrypting the content 12 if in fact derived from a seed may be obtained by the transmitter 14x by obtaining the seed from the corresponding license 16 and deriving (KD) from the seed. If the content 12 is not initially encrypted at the transmitter 14x, the transmitter selects a seed, derives (KD) therefrom and encrypts the content 12 according to such (KD). In one embodiment of the present invention, a signature or MAC is generated based on the session response and is appended thereto, where the signature/MAC binds the policy to the remainder of the session response and therefore can be employed to verify the session response. As may be appreciated, such binding is necessary so that the constituent parts of the session response cannot be accessed apart from each other, as a nefarious entity wishing to steal the content 13 may attempt to do. In one embodiment of the present invention, the signature/MAC is based on a symmetric integrity key (KI) selected for the session response, and thus the session response also includes therein the selected (KI) encrypted according to (PU-R) to result in (PU-R(KI)). Thus, only the receiver 14r with the corresponding (PR-R) can obtain (KI) from the session response and verify same, as will be seen below. Alternatively, and again, rather than sending (KI) encrypted by (PU-R), it may be the case that the transmitter 14x and receiver 14r both share knowledge of how to derive (KI) from a seed, whereby the seed is sent in the session response encrypted by (PU-R). Note that such seed may be the same seed from which (KD) was derived or may be a different seed. In one embodiment of the present invention, the session response from the transmitter 14x to the receiver 14r also includes the version number of the revocation list 26 of the transmitter (V-RL-X). As was alluded to above, if the receiver 14r determines therefrom that (V-RL-R) is more current than (V-RL-X), the receiver 14r may send the revocation list 26 thereof to the transmitter 14x. Alternatively, it may be that the transmitter 14x has already determined by comparing the (V-RL-R) as received from the session request with (V-RL-X) that (V-RL-X) is more current than (V-RL-R), in which case the transmitter 14x may send the revocation list 26 thereof to the receiver 14r. In one embodiment of the present invention, the session response from the transmitter 14x to the receiver 14r also includes a session ID-X generated by the transmitter 14x to identify the session to the receiver 14r, where such session ID-X differs from the session ID-R from the receiver 14r. As may be appreciated, the transmitter 14x may generate the session ID-X inasmuch as the session ID-R is not verifiable by a signature/MAC in the session request from the receiver 14r, may generate the session ID-X because the format of the session ID-R is not acceptable to the transmitter 14x, or may generate the session ID-R simply as a matter of good practice. The transmitter 14x in conjunction with sending the session response as at step 507 also appropriately stores the session request or at least a portion thereof and the session response or at least a portion thereof in an appropriate session store 30x for later retrieval and use (step 509). In particular, and as seen below, the transmitter 14x stores in the session store 30x at least the identification of the content 12 and at least one of the session ID-X and the session ID-R. At any rate, upon receiving the session response from the transmitter 14x, the receiver 14r retrieves (PU-R(KI)) and applies the corresponding (PR-R) thereto to result in the integrity key (KI), and then verifies the signature/MAC of the session response based on such (KI) (step 511). Alternatively, the receiver 14r retrieves the encrypted seed, applies the corresponding (PR-R) thereto to result in the seed, and derives the integrity key (KI) based on the seed, and then verifies the signature/MAC of the session response based on such (KI). Presuming that such signature/MAC does indeed verify, the session between the transmitter 14x and the receiver 14r is then established, and the receiver 14r appropriately stores the session response from the transmitter 14x or at least a portion thereof in an appropriate session store 30r for later retrieval and use (step 513). Note here that although the session has been established with regard to the piece of content 12 identified in the session request from the receiver 14r as at step 501, the piece of content 12 has not as yet been delivered to the receiver 14r. Thus, and referring now to FIG. 6, in one embodiment of the present invention, content 12 is transferred from the transmitter 14x to the receiver 14r by way of the network 17. In particular, and as seen, the receiver 14r retrieves the session response or part thereof as stored at step 513 from the session store 30r thereof and obtains from the retrieved session response the session ID-X as generated by the transmitter 14x (step 601). Alternatively, if a session ID-X as generated by the transmitter 14x is not set forth in the session response, the receiver 14r obtains therefrom the session ID-R as generated by the receiver 14r. Thereafter, the receiver 14r sends a transfer request to the transmitter 14x by way of the network 17 (step 603), where the transfer request includes the session ID-X or ID-R (hereinafter, ‘ID’). The transmitter 14x upon receiving such transfer request identifies the session ID therein and retrieves the session request or part thereof and session response or part thereof as stored at step 509 from the session store 30x thereof based on the identified session ID (step 605). From such session response, the transmitter 14x retrieves the identification of the content 12 and then locates the package 13 containing such identified content 12 or else creates such package 13 (step 609). Note that such locating and/or creating may be performed above in connection composing the session response during step 507 of registration as shown in FIG. 5, especially if the transmitter 14x creates the package 13 with the content 12 therein encrypted according to (KD) to result in (KD(content)). At any rate, the transmitter 14x sends a transfer response to the receiver 14r by way of the network 17 (step 611), where the transfer response includes the package 13 with the content 12 therein encrypted according to (KD) to result in (KD(content)). The receiver 14r upon receiving such transfer response may then retrieve the session response from the session store 30r thereof (step 613), retrieve the policy and (PU-R(KD)) or (PU-R(seed)) from the retrieved session response (step 615), confirm that the policy allows the receiver 14r to render the content 12 in the manner sought (step 617), and presuming such confirmation is gained may then apply (PR-R) to (PU-R(KD)) to reveal (KD) or else (PR-R) to (PU-R(seed)) to reveal the seed and then derive (KD) therefrom (step 619), apply (KD) to (KD(content)) to reveal the content 12 (step 621), and then in fact render the content 12 in accordance with the policy (step 623). Conclusion The present invention may be practiced with regard to any appropriate transmitter 14x and receiver 14r interconnected by a network 17, presuming that such transmitter 14x and receiver 14r have appropriate trusted components 18 thereon and the receiver 14r has a certificate 22 from a certifying authority approved by the transmitter 14x. As should now be appreciated, with the present invention as set forth herein, content 12 is delivered from a transmitter 14x to a receiver 14r by way of an interconnecting network 17 according to a method that is independent of the actual protocols used for transporting the content 12 by way of the network, and that is independent to the format of the content 12. Note that although the present invention is disclosed primarily in terms of a receiver 14r that performs rendering such as playback or rasterizing among other things, the receiver 14r may perform other actions without departing from the spirit and scope of the present invention. Such other actions include but are not limited to transferring the content 12 to a separate computing device 14 such as a personal computer, a portable device, or the like; transferring the content 12 to a portable memory, a magnetic or optical disk, or the like; transferring the content 12 in a different protection scheme; exporting the content 12 without any protection scheme; transferring or exporting the content 12 in a different format; etc. In general, then, the transferred content 12 may be rendered, distributed, edited, employed for content creation, editing, and distribution, or the like. For example, content 12 could have policy that allows or forbids the content 12 to be edited in certain ways. The programming necessary to effectuate the processes performed in connection with the present invention is relatively straight-forward and should be apparent to the relevant programming public. Accordingly, such programming is not attached hereto. Any particular programming, then, may be employed to effectuate the present invention without departing from the spirit and scope thereof. In the foregoing description, it can be seen that the present invention comprises a new and useful architecture and method that allows content 12 with a corresponding license 16 tied to one computing device 14 in a network 17 or the like to be rendered by any other appropriate computing device 14 in the network 17, presuming the license 16 so allows. With the method, access to the content 12 is of negotiated as between the computing devices 14 in the network 17. It should be appreciated that changes could be made to the embodiments described above without departing from the inventive concepts thereof. Perhaps most significantly, it is to be appreciated that although establishing a session (FIG. 5) and transferring content 12 (FIG. 6) are set forth essentially separately, such establishing and transferring may be performed essentially as a single procedure. As may be appreciated, in such a situation, several steps and items may be omitted if perceived as unnecessary. Other possible changes bearing mention include removal of various IDs such as session IDs and registration IDs. In general then, it should be understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>As is known, and referring now to FIG. 1 , a rights management (RM) and enforcement system is highly desirable in connection with digital content 12 such as digital audio, digital video, digital text, digital data, digital multimedia, etc., where such digital content 12 is to be distributed to users. Upon being received by the user, such user renders or ‘plays’ the digital content with the aid of an appropriate rendering device such as a media player on a personal computer 14 , a portable playback device or the like. Typically, a content owner distributing such digital content 12 wishes to restrict what the user can do with such distributed digital content 12 . For example, the content owner may wish to restrict the user from copying and re-distributing such content 12 to a second user, or may wish to allow distributed digital content 12 to be played only a limited number of times, only for a certain total time, only on a certain type of machine, only on a certain type of media player, only by a certain type of user, etc. However, after distribution has occurred, such content owner has very little if any control over the digital content 12 . An RM system 10 , then, allows the controlled rendering or playing of arbitrary forms of digital content 12 , where such control is flexible and definable by the content owner of such digital content. Typically, content 12 is distributed to the user in the form of a package 13 by way of any appropriate distribution channel. The digital content package 13 as distributed may include the digital content 12 encrypted with a symmetric encryption/decryption key (KD), (i.e., (KD(CONTENT))), as well as other information identifying the content, how to acquire a license for such content, etc. The trust-based RM system 10 allows an owner of digital content 12 to specify rules that must be satisfied before such digital content 12 is allowed to be rendered. Such rules can include the aforementioned requirements and/or others, and may be embodied within a digital license 16 that the user/user's computing device 14 (hereinafter, such terms are interchangeable unless circumstances require otherwise) must obtain from the content owner or an agent thereof, or such rules may already be attached to the content 12 . Such license 16 may for example include the decryption key (KD) for decrypting the digital content 12 , perhaps encrypted according to another key decryptable by the user's computing device or other playback device. The content owner for a piece of digital content 12 would prefer not to distribute the content 12 to the user unless such owner can trust that the user will abide by the rules specified by such content owner in the license 16 or elsewhere. Preferably, then, the user's computing device 14 or other playback device is provided with a trusted component or mechanism 18 that will not render the digital content 12 except according to such rules. The trusted component 18 typically has an evaluator 20 that reviews the rules, and determines based on the reviewed rules whether the requesting user has the right to render the requested digital content 12 in the manner sought, among other things. As should be understood, the evaluator 20 is trusted in the RM system 10 to carry out the wishes of the owner of the digital content 12 according to the rules, and the user should not be able to easily alter such trusted component 18 and/or the evaluator 20 for any purpose, nefarious or otherwise. As should be understood, the rules for rendering the content 12 can specify whether the user has rights to so render based on any of several factors, including who the user is, where the user is located, what type of computing device 14 or other playback device the user is using, what rendering application is calling the RM system 10 , the date, the time, etc. In addition, the rules may limit rendering to a pre-determined number of plays, or pre-determined play time, for example. The rules may be specified according to any appropriate language and syntax. For example, the language may simply specify attributes and values that must be satisfied (DATE must be later than X, e.g.), or may require the performance of functions according to a specified script (IF DATE greater than X, THEN DO . . . , e.g.). Upon the evaluator 20 determining that the user satisfies the rules, the digital content 12 can then be rendered. In particular, to render the content 12 , the decryption key (KD) is obtained from a pre-defined source and is applied to (KD(CONTENT)) from the content package 13 to result in the actual content 12 , and the actual content 12 is then in fact rendered. In an RM system 10 , content 12 is packaged for use by a user by encrypting such content 12 and associating a set of rules with the content 12 , whereby the content 12 can be rendered only in accordance with the rules. Because the content 12 can only be rendered in accordance with the rules, then, the content 12 may be freely distributed. Typically, the content 12 is encrypted according to a symmetric key such as the aforementioned key (KD) to result in (KD(content)), and (KD(content)) therefore is also decrypted according to (KD) to result in the content 12 . Such (KD) is in turn included within the license 16 corresponding to the content 12 . Oftentimes, such (KD) is encrypted according to a public key such as the public key of the computing device 14 (PU-C) upon which the content 12 is to be rendered, resulting in (PU-C(KD)). Note, though, that other public keys may be employed, such as for example a public key of a user, a public key of a group of which the user is a member, etc. Thus, and presuming the public key is (PU-C), the license 16 with (PU-C(KD)) is tied to and may only be used in connection with such computing device 14 inasmuch as only such computing device 14 should have access to the private key (PR-C) corresponding to (PU-C). As should be appreciated, such (PR-C) is necessary to decrypt (PU-C(KD)) to obtain (KD), and should be closely held by such computing device 14 . It is to be appreciated that a user at times may have a plurality of computing devices 14 that are networked or otherwise inter-connected in a network 17 or the like. In such a situation, it may be the case that the user may obtain a license 16 to render a corresponding piece of content 12 , where the license 16 includes (KD) for the piece of content 12 encrypted according to the public key of a first computing device 14 (PU-C1) to result in (PU-C1(KD)), and thus such license 16 is tied to such first computing device 14 . Moreover, in such a situation, it may further be the case that the user wishes to render the content 12 on a second computing device 14 that is in the network 17 with the first computing device 14 . However, and crucially, such second computing device 14 does not have access to the private key of the first computing device 14 (PR-C1), as such first computing device 14 should be loathe to reveal such (PR-C1) to such second computing device 14 . Instead, such second computing device 14 only has access to the private key of such second computing device 14 (PR-C2), which of course cannot be applied to (PU-C1(KD)) to reveal such (KD). Thus, without additional architecture, the second computing device 14 is unable to obtain (KD) from (PU-C1(KD)) and thereby decrypt (KD(content)), as is necessary to render such content 12 . Such inability exists even though the user can render the content 12 by way of the first computing device 14 , the second computing device 14 is in the network 17 with the first computing device 14 , and both the first and second computing devices 14 are under the control of the same user. Accordingly, a need exists for an architecture and method that allow content 12 with a corresponding license 16 tied to one computing device 14 in a network 17 or the like to be rendered by any other appropriate computing device 14 in the network 17 , presuming the license 16 so allows. In particular, a need exists for a method of negotiating access to the content 12 as between the computing devices 14 in the network 17 . | <SOH> SUMMARY OF THE INVENTION <EOH>The aforementioned needs are satisfied at least in part by the present invention in which a method is provided in connection with a first computing device (‘transmitter’) and a second computing device (‘receiver’) interconnected by a network, where the transmitter transmits protected digital content to the receiver in a manner so that the receiver can access the content. The content is encrypted and decryptable according to a content key (KD). In the method, the receiver sends a session request to the transmitter, where the session request includes an identification of the content to the transmitter, an action to be taken with the content, and a unique identification of the receiver. The transmitter receives the session request from the receiver, determines from the unique identification of the receiver in the session request that the receiver is in fact registered to the transmitter, obtains a digital license corresponding to the identified content in the session request, reviews policy set forth in the license to determine that the license allows the transmitter to provide access to the content to the receiver and also allows the action in the session request, and sends a session response to the receiver, where the session response includes the policy from the license, the unique identification of the receiver, and the content key (KD) for decrypting the encrypted content, (KD) being protected in a form obtainable by the receiver. The transmitter obtains the content encrypted according to (KD) to result in (KD(content)), and sends (KD(content) to the-receiver. The receiver receives the session response and (KD(content)), retrieves the policy and the protected content key (KD) for decrypting the encrypted content from the session response, confirms that the policy allows the receiver to render the content, obtains the content key (KD), applies (KD) to (KD(content)) to reveal the content, and then in fact renders the content in accordance with the policy. | 20040419 | 20081014 | 20051020 | 71826.0 | 0 | ZEE, EDWARD | RENDERING PROTECTED DIGITAL CONTENT WITHIN A NETWORK OF COMPUTING DEVICES OR THE LIKE | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,827,563 | ACCEPTED | PLAYPEN WITH DOUBLE COLUMNS AT EACH CORNER | A playpen with columns comprises a plurality of first corners each having a first bulge and a second bulge, a plurality of second corners each having a first sleeve and a second sleeve, a first rod unit connecting the first corners, a second rod unit connecting the second corners, a plurality of first columns whose one end bushes around the first bulge and another end thereof is inserted into the first sleeve, a plurality of second columns whose one end bushes around the second bulge and another end thereof is inserted into the second sleeve, and a boundary shelter unit covering the first columns. The distance between two opposite second columns is larger than that of two opposite first columns so that the second columns are revealed. | 1. A playpen with double columns at each corner of said playpen, comprising: a plurality of first corner components; a first rod unit connecting the first corner components; a plurality of second corner components; a second rod unit connecting the second corner components; a plurality of first columns, each said first column having two opposite ends, one end being connected to a first corner component, another end of said column being connected to a second corner component; a plurality of second columns, each said second column having two opposite ends, one end being connected to a first corner component, another end of said second column being connected to a second corner component; wherein a distance between the two second columns is larger than that between the two first columns, whereby a gap is formed between an adjacent first column and a second column; and a boundary sheet extends through each said gap and covers the first columns. 2. The playpen as claimed in claim 1, wherein each said second corner component comprises a first sleeve and a second sleeve connecting respectively with the first column and the second column. 3. The playpen as claimed in claim 1, wherein each said first corner component comprises a first bulge and a second bulge connecting respectively with the first column and the second column. 4. The playpen as claimed in claim 3, wherein each of the first and second columns extend respectively around the first and second bulges. 5. The playpen as claimed in claim 1 or 4, wherein the playpen comprises a plurality of rivets for securing the first and second columns to respectively the first corner components. 6. The playpen as claimed in claim 1, wherein the playpen comprises a plurality of washers for securing the boundary sheet respectively to the ends of the first columns which are adjacent to the first corner components. | FIELD OF THE INVENTION The present invention relates generally to a playpen, and more particularly to a playpen with multiple columns, such as possessing double columns at each corner of the playpen. DISCUSSION OF THE PRIOR ART A conventional playpen 3, generally of the kind disclosed in U.S. Pat. No. 6,539,563 B1 is shown in FIG. 1 of the present drawings. The conventional playpen 3 mainly consists of a rectangular frame 31 and a boundary sheet 33 covering five surfaces of the frame 31. The frame 31 has a pole 311 at respectively each of four nooks or corners, and the boundary sheet 33 completely covers all of the poles 311 such that the conventional playpen 3 is fully covered by the boundary sheet 33 in appearance and thus the visual feeling of the playpen abounding in various materials, such as metal and plastic, is not presently evident. Besides, the poles 311 fail to provide additional space for the arranging of any artificial decoration. Therefore, the conventional playpen 3 with one pole at each nook or corner, on the one hand, sets a limit in the forming of design patterns to the designer, while on the other hand failing to meet a variety of needs for various consumers. Moreover, the conventional playpen 3, which is equipped with one pole at each nook or corner, needs poles with each possessing a larger diameter in order to meet requirements with respect to strength in construction, which make the conventional playpen 3 seem clumsy in appearance. SUMMARY OF THE INVENTION Accordingly, the present invention relates to a playpen equipped with double columns at each corner that are substantially intended to obviate one or more of the problems due to the limitations and disadvantages encountered in the prior art. One object of the present invention is the provision of a playpen with columns which can provide a feeling of the structure abounding in a variety of materials. Another object of the present invention is the provision of a playpen with columns which allows for the application of additional artificial decorations. A further object of the present invention is the provision of a light and efficient playpen equipped with double columns at each corner. Additional features and advantages of the invention will be set forth in the description which follows. The objectives and advantages of the invention will be realized and attained by the structure as particularly set forth in the written description and claims as well as illustrated in the appended drawings. To achieve these and other advantages and according to the purpose of the present invention, as embodied and broadly described, the playpen with the double columns comprises: a plurality of first corners; a first rod unit connecting the first corners; a plurality of second corners; a second rod unit connecting the second corners; a plurality of first columns each having two opposite ends, one end being connected to the first corner, another end being connected to the second corner; a plurality of second columns each having two opposite ends, one end being connected to the first corner, another end being connected to the second corner; wherein the length of the two opposite second columns is larger than that of the two opposite first columns, and a gap exists between the adjacent first column and the second column and with a boundary sheet extending through each gap and covering the first columns. In a preferred aspect, each second corner further comprises a first sleeve and a 20 second sleeve for respectively connecting with the first column and the second column. Moreover, each first corner further comprises preferably a first bulge and a second bulge for respectively connecting with the first column and the second column. It is preferred that the columns respectively extend around the bulges. It is another preferred feature that the playpen further comprises a plurality of rivets in order to secure the columns to respectively the first corners. Additionally, the playpen further comprises a plurality of washers to secure the boundary sheet to respectively the ends of the first columns adjacent to the first corners. It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory and are intended to provide a further non-limiting explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a portion of the specification, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention. In the drawings: FIG. 1 is an assembled perspective view illustrating a conventional playpen; FIG. 2 is an assembled perspective view illustrating the frame of the playpen without a boundary shelter unit according to the present invention; FIG. 3 is an exploded perspective view illustrating, on an enlarged scale, the first corner component near according to the present invention, wherein the first corner component is shown sectioned; FIG. 4 is an exploded perspective view illustrating the second corner near according to the present invention; and FIG. 5 is an assembled perspective view illustrating the playpen with double columns in the corners according to the present invention; DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 2 and 5, the playpen 1 with columns according to the present invention is substantially constructed as a rectangular body and comprises four first corner component 11 situated at lower end of the playpen 1, four second corner components 12 situated at upper end of the playpen 1, a first rod unit 13 laterally connecting the first corner components 11, a second rod unit 14 laterally connecting the second corner components 12, four first columns 15 and four second columns 16 vertically connecting the first corner components 11 and the second corner components 12, and a flexible boundary sheet 17 covering the bottom surface and four side surfaces of the playpen 1 together with the columns. As shown in FIG. 3, each thin, flat and shell-like first corner component 11 includes an opening 111 provided at the upper end thereof, a first bulge 112 and a second bulge 113 extending upwardly from the bottom thereof, and three holes 114 provided in each sidewall thereof. As shown in FIG. 4, each second corner component 12 is substantially formed as a hollow triangular body and includes a slit 121 extending from the bottom end to two nooks thereof, a first sleeve 122 and a second sleeve 123 extending downwardly from the upper end thereof, and the apertures 124 provided in the sidewalls thereof. Referring jointly to FIGS. 2 and 4, each rod of the first rod unit 13 is respectively inserted into the opening 111 of each first corner component 11. Then, a rivet 191 is respectively passed through the holes 114 of each first corner component 11 and the bore 131 of each rod of the first rod unit 13 50 as to pivotally connect the first rod unit 13 together with the four first corner components 11. Similarly, each rod of the second rod unit 14 is respectively inserted into the slit 121 of each second corner component 12. Then, a rivet 193 is respectively passed through the apertures 124 of each second corner component 12 and the aperture 141 in each rod of the second rod unit 14 so as to pivotally connect the second rod unit 14 with the four second corner components 12. Thereafter, each first column 15 is respectively inserted downwardly into each first corner component 11 and washers around each first bulge 112. Then, a rivet 194 is respectively passed through the holes 114 of each first corner component 11 and the bore 151 of each first column 15 so as to connect each first column 15 with each first corner component 11. As far as the upper end of each first column 15, it is inserted into and secured by each first sleeve 122. Similarly, each second column 16 is respectively inserted downwardly into each first corner component 11 and washers around each second bulge 113. Then, a rivet 195 is respectively passed through the holes 114 of each first corner component 11 and the orifice 161 in each second column 16 so as to connect each second column 16 with each first corner component 11. As far as the upper end of each second column 16, it is inserted into and secured by each second sleeve 123. Having been assembled to this point, the rectangular frame shown in FIG. 2 of the playpen 1 with double columns is completed in its assembly, wherein the distance between two opposite second columns 16 is larger than that between two opposite first columns 15 and the diameter of the first column 15 is smaller than that of the second column 16. Besides, the adjacent first column 15 and second column 16 have similar convex profiles and are parallel to each other a gap remaining therebetween. However, the above description only represents a preferred embodiment of the present invention, whereas alternatively, or additionally, the number and profile of the first columns 15 and the second columns 16 may be varied depending on design considerations. Furthermore, the rods of the first rod unit 13, the rods of the second rod unit 14, the first columns 15, and the second columns 16 may be either solid or hollow in construction. Referring jointly to FIGS. 2 and 5, the upper end of the boundary sheet 17 is secured entirely (or partially) to the second rod unit 14. The sidewalls of the boundary sheet 17 pass through each gap, which is present between each pair of adjacent first column 15 and second column 16, and simultaneously cover each first column 15. Then, a screw 192 is passed through a washer 18 of the playpen 1 and an aperture 152 (shown in FIG. 3) situated at the first column 15 so as to secure the boundary sheet 17 to the lower end of each first column 15 and unbend or straighten the whole boundary sheet 17. At the same time, since each second column 16 is not covered by the boundary sheet 17, the color and nature of the employed material, such as metal or plastic, can be exposed or artificial decorations can be added to each second column 16 in order to provide a designer with additional space for imparting a different visual feeling from any previous visual appearance for the boundary sheet 17. This invention has been disclosed in terms of specific embodiments. It will be 25 apparent that many modifications can be made to the disclosed structures without departing from the invention. Therefore, it is the intent of the appended claims to cover all such variations and modifications as come within the breadth and scope of this invention. | <SOH> FIELD OF THE INVENTION <EOH>The present invention relates generally to a playpen, and more particularly to a playpen with multiple columns, such as possessing double columns at each corner of the playpen. | <SOH> SUMMARY OF THE INVENTION <EOH>Accordingly, the present invention relates to a playpen equipped with double columns at each corner that are substantially intended to obviate one or more of the problems due to the limitations and disadvantages encountered in the prior art. One object of the present invention is the provision of a playpen with columns which can provide a feeling of the structure abounding in a variety of materials. Another object of the present invention is the provision of a playpen with columns which allows for the application of additional artificial decorations. A further object of the present invention is the provision of a light and efficient playpen equipped with double columns at each corner. Additional features and advantages of the invention will be set forth in the description which follows. The objectives and advantages of the invention will be realized and attained by the structure as particularly set forth in the written description and claims as well as illustrated in the appended drawings. To achieve these and other advantages and according to the purpose of the present invention, as embodied and broadly described, the playpen with the double columns comprises: a plurality of first corners; a first rod unit connecting the first corners; a plurality of second corners; a second rod unit connecting the second corners; a plurality of first columns each having two opposite ends, one end being connected to the first corner, another end being connected to the second corner; a plurality of second columns each having two opposite ends, one end being connected to the first corner, another end being connected to the second corner; wherein the length of the two opposite second columns is larger than that of the two opposite first columns, and a gap exists between the adjacent first column and the second column and with a boundary sheet extending through each gap and covering the first columns. In a preferred aspect, each second corner further comprises a first sleeve and a 20 second sleeve for respectively connecting with the first column and the second column. Moreover, each first corner further comprises preferably a first bulge and a second bulge for respectively connecting with the first column and the second column. It is preferred that the columns respectively extend around the bulges. It is another preferred feature that the playpen further comprises a plurality of rivets in order to secure the columns to respectively the first corners. Additionally, the playpen further comprises a plurality of washers to secure the boundary sheet to respectively the ends of the first columns adjacent to the first corners. It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory and are intended to provide a further non-limiting explanation of the invention as claimed. | 20040419 | 20051018 | 20051020 | 95858.0 | 2 | GROSZ, ALEXANDER | PLAYPEN WITH DOUBLE COLUMNS AT EACH CORNER | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,827,737 | ACCEPTED | SYSTEM FOR MARKETING LEISURE ACTIVITY SERVICES THROUGH PREPAID TICKETS | One-time-use tickets containing a unique identification code that allow for prepayment of entertainment or personal services are distributed and sold. When a ticket is sold, it is activated by the seller notifying a ticket information manager of its sale, at which time the ticket's unique identification code is recorded by the ticket information manager. Part of the sale price is transferred by the vendor to an account maintained by a ticketing program manager. Ticket-holders present the ticket for redemption of the particular service from an agreed service provider. The service provider verifies the ticket's validity by checking with the ticket information manager that the ticket's unique identification code is valid and that the ticket has been activated. While the purchase price of the ticket is fixed, service providers will receive their agreed payment price from the ticketing program manager's account when a ticket user redeems a ticket regardless of whether that price is higher or lower than the ticket purchase price. | 1-3. (canceled) 4. The method of claim 12, wherein at least one of said, activation, optional purchase and confirmation steps includes transmission and reception of said communications over an interactive voice response system. 5. The method of claim 12, wherein at least one of said activation, optional purchase and confirmation steps includes the step of transmission and reception of said communications over a public data communication network. 6. The method of claim 12, wherein said one-time-use ticket has a maximum number of incremental values that may be added to the one-time-use ticket and further comprising the additional step of (j) verifying that any additional value to be added does not exceed the maximum value. 7. The method of claim 12, wherein said one-time-use ticket is valid for redemption for a limited period of time after activation and further comprising the additional step of (j) the service provider verifying with the ticket information manager an expiration date of the ticket and that the ticket has not been presented for redemption after the expiration date. 8. The method of claim 12, wherein purchaser information is recorded by the ticket information manager at the time of purchase and further comprising at least one said purchaser obtaining a replacement one-time-use ticket upon presentation of identification after the original said ticket is lost or stolen and has not already been accepted by a service provider. 9. The method of claim 12, wherein the ticket comprises indicia of a credit card including at least one of a printed multi-digit numerical code, an embossed multi-digit numerical code, a magnetic strip, a barcode and a stored encoded chip, representing a corresponding code and which is readable by use of standard credit card equipment coupled to a communication network, and wherein at least one of steps (c), (d), (g) and (h) includes transmission and reception of said data over said standard credit card equipment and network. 10. The method of claim 12, wherein said one-time-use ticket contains a recordable medium and wherein the device is blank when received by a seller and validation information and purchase data are recorded on said recordable medium in conjunction with purchase. 11. The method of claim 12 further comprising communicating between the ticketholder and the ticket information manager over a public communication network, for at least one of checking a ticket status and a number of incremental credits thereof, including access to a processor having access to stored ticket data, and wherein said communicating excludes reporting of any monetary value associated with the ticket but includes reporting a number of incremental credits purchased to date. 12. A method for provision of prepaid services, comprising the steps of: (a) distribution and sale of one-time-use tickets, each possessing a substantially unique identification code and representing an initial value to be remitted for a single use of a desired service, each said ticket to be valid for a single use at any one of a plurality of service providers; (b) purchase of at least one said ticket by a customer; (c) activation of said ticket be a seller thereof, said activation comprising communication with a ticket information manager that a particular ticket has been sold and validation by the ticket information manager of the unique identification code of the ticket; (d) transfer of a predetermined amount from the purchase price in favor of a ticketing program manager; (e) presentation of the ticket by a ticket-holder to one of the plurality of service providers for redemption in exchange for a single use of the desired service from said one of the service providers, said one of the service providers being selected by the ticket-holder among the plurality of service providers; (f) wherein the ticket is redeemable at any one of said plurality of service providers for said single use, although a price debited for said service by at least certain of said service providers is different from a price debited by others of said service providers for the same said service; (g) confirmation by the service provider of the tickets validity with the ticket information manager; and (h) payment by the ticketing program manager, at the price debited for said service by said one of said service providers, in favor of the service provider for the single use of the service; further comprising (i) permitting optional purchase of additional incremental credit above a base ticket value on the ticket by the customers said purchase comprising communicating an additional purchased value to the ticketing program manager and payment in favor of the ticketing program manager therefore, and presentation of the ticket by a ticket-holder to one of a plurality of service providers in exchange for use of the provider's service where the price debited for said service by said service provider can be higher than the base ticket value, wherein said additional incremental credit is also useable to redeem services from the service provider when the ticket is presented for use on a given occasion, and wherein the ticket user can check a ticket status with the ticket information manager through a telephone connection to an interactive voice response processor having access to stored ticket data and where the ticket user is not given the monetary value associated with the ticket but the number of incremental credits purchased to date. 13. (canceled) 14. The system of claim 22, further comprising: (j) means for determining whether the ticket presented to the service provider has exceeded an expiration date. 15. The system of claim 22, further comprising: (k) means for the user to purchase additional incremental value on said ticket; (l) means for the data processing platform to store information indicating the addition of value to the ticket; and (m) means for a service provider to verify through communications with the data processing platform the amount of additional incremental value added to the ticket. 16. The system of claim 22, wherein at least one of (c) and (g) includes transmission and reception of communications over an interactive voice response system. 17. The system of claim 22, wherein at least one of (c) and (g) includes transmission and reception of communications over a public data network. 18. The system of claim 22, wherein said one-time-use ticket is valid for redemption for a limited period of time after activation, and further comprising the service provider verifying with the account manager the expiration date of the ticket and that the ticket has not been presented for redemption after the expiration of the limited time period. 19. The system of claim 22, wherein purchaser information is recorded by the ticket information manager at the time of purchase and said purchaser may obtain a replacement one-time-use ticket upon presentation of proper identification if the original is lost or stolen and the original has not already been accepted by a service provider. 20. The system of claim 22 wherein the ticket contains indicia of a credit card comprising at least one of a printed numerical code, an embossed 16 digit unique numerical code, and code represented by at least one of optical, magnetic and electronic encoding, which code is readable using standard point of sale equipment and wherein at least one of (c), (d), (g) and (h) includes transmission and reception of communications over a standard credit card network. 21. The system of claim 22, wherein said one-time-use ticket contains a recordable medium such as a magnetic strip and wherein the recordable medium has a blank area when received by a seller, and wherein validation information and purchase data are recorded on said recordable medium in conjunction with purchase. 22. A prepaid service account management system, comprising: (a) a data processing platform associated with a merchant payment network; (b) means for receiving from a ticket distributor and storing for access by the data processing platform, a communication identifying a ticket with a substantially unique identification code; (c) wherein the data processing platform comprises at least one processor programmed for comparing the identification code with a list of such codes for tickets that have been distributed by a ticketing program manager; (d) a database memory accessible to the data processing platform for storing information indicating that a ticket with a particular said code has been purchased, and also for storing an indication of whether the ticket has been redeemed; (e) means for receiving from a service provider that is an authorized participant in the merchant payment network, a communication identifying a ticket with a unique identification code; (f) a database memory for storing an inclusion list identifying among all service providers that are authorized participants in the merchant payment network, a subset of participants that are authorized service providers for at least one service; (g) at least one processor programmed for comparing a unique identification code received from a service provider with a list of codes for tickers that have been sold and accessing the database memory; (h) means for communicating with a service provider that is in the inclusion list and to whom a ticket has been presented for redemption that the ticket with said identification code is validly redeemable for a single use of a desired service, wherein said service provider is selected by ticket-holder among said subset of participants of the inclusion list, and marking the database memory to show that the ticket has been used a single time; and (i) wherein the processor is programmed to credit the service provider for redemption of the ticket and to signal refusal if the database indicates that the ticket is not properly redeemable as presented, and wherein a ticket-holder can check a ticket's status with the ticket information manager by access to an Internet site connected to a processor coupled to stored ticket data, and wherein the processor is programmed to report a number of incremental units associated with the ticket, while refraining from reporting an associated purchase value thereof. 23. A prepaid services account management system, comprising: (a) a data processing platform associated with a merchant payment network; (b) means for receiving from a ticket distributor and storing for access by the data processing platform, a communication identifying a ticket with a substantially unique identification code; (c) wherein the data processing platform comprises at least one processor programmed for comparing the identification code with a list of such codes for tickets that have been distributed by a ticketing program manager; (d) a database memory accessible to the data processing platform for storing information indicating that a ticket with a particular said code has been purchased, and also for storing an indication of whether the ticket has been redeemed; (e) means for receiving from a service provider that is an authorized participant in the merchant payment network, a communication identifying a ticket with a unique identification code; (f) a database memory for storing an inclusion list identifying among all service providers that are authorized participants in the merchant payment network a subset of participants that are authorized service providers for at least one service; (g) at least one processor programmed for comparing unique identification code received from a service provider with a list of codes for tickets that have been sold and accessing the database memory; (h) means for communicating with a service provider that is in the inclusion list and to whom a ticket has been presented for redemption that the ticket with said identification code is validly redeemable for a single use of a desired service, wherein said service provider is selected by a ticket-holder among said subset of participants of the inclusion list, and marking the database memory to show that the ticket has been used a single time; and (i) wherein the processor is programmed to credit the service provider for redemption of the ticket and to signal refusal if the database indicates that the ticket is not properly redeemable as presented, and wherein the ticket user can check a ticket's status with the ticket information manager through a telephone connection to an interactive voice response processor having access to stored ticket data, and wherein the processor is programmed to report a number of incremental units associated with the ticket, while refraining from reporting an associated purchase value thereof. | FIELD OF THE INVENTION The invention relates to marketing and distributing services, especially participatory sports or entertainment services, by collecting a prepayment and issuing to a customer a ticket or similar indicia that can be redeemed for a particular service. The service is one that can be obtained at the customer's option from any of a plurality of distinct service providers, including providers that normally charge more or less than others for the particular service involved. The invention further involves accounting for the usage and payment for services on this basis. BACKGROUND OF THE INVENTION Goods and services are typically obtained in exchange for payment and the payment might be rendered in various ways and in various amounts, such as by tender of cash currency, funds transfer between accounts, debit card purchase and exhaustion, credit arrangements involving future payment, barter or various other techniques. The particular goods or services that a customer might obtain from different providers differ. The reputations of providers differ. The manner of providing services, such as the time of day or as a function of demand or other aspects also differ. Importantly, the providers also demand different prices. The differences between available offerings of goods and services generally boil down to differences in the costs and benefits of available goods and services that consumers have the option to choose. The costs and benefits of the possible choices are judged and compared by customers when making purchasing decisions. The customers seek the greatest benefit per unit cost and are free to make selections among a variety of different providers' offerings and terms, or even to substitute one type of service for another according to the customer's needs. The relative merits and different options are perceived differently by different consumers, such that some consumers are willing to pay more or less than others for particular aspects of goods or services. The confluence of offerings (including what is offered and the terms of payment) with the selections made by consumers is the nature of the market of supply and demand by which resources are allocated among consumers in a market economy. Not all consumer transactions are classic exercises of supply and demand wherein the customer has the utmost control and choice among differing alternatives with incrementally different costs and/or different pricing and payment arrangements. One example is a vendor's prepaid gift indicia, which can take various forms ranging from an authorized numbered slip bearing the vendor's name and a dollar amount to plastic cards bearing the vendor's logo and having a magnetically readable strip with a predetermined dollar value, each redeemable at the vendor's sales outlets. A prepaid gift indicia is generally issued by a particular retailer and can only be redeemed at that retailer's facilities. In this situation, the person who purchases the gift indicia may exercise a degree of choice, but the person who redeems it (typically the recipient of the gift) has no choice except to use the issuing retailer as the provider. Inasmuch as the issuer and the provider are the same entity, the issuer/provider has full control of the extent to which the selling price of the gift card corresponds to the offering price of the goods or services that are delivered. It is conceivable that the issuer/provider may include a premium or discount to encourage patronage and/or purchase of gift indica, but within the control of the issuer/provider, the goods or services are provided in exchange for an amount that is related to the issuer/provider's pricing schedules. It its known that providers of personal entertainment and sporting services, can issue a gift ticket that represents an incremental cash value or an incremental quantity of their services. This is possible because pricing and terms upon the sale of the gift ticket are controlled by the same party that controls the nature, quality and delivery terms of the services. As a result, the issuer/provider can issue a gift ticket for a given cash value or for a given increment of services. Thus a gift ticket or coupon might be granted for one pass to a matinee show or one Saturday afternoon bowling game, presumably with the ticket priced at an amount related to the pricing of the associated service. If the gift ticket is not defined as equal to a given service and/or if the issuer offers different services at different prices, then the gift ticket is denominated as a cash value and the user is entitled to deduct from the value on the ticket when paying for services, until the value associated with the ticket is exhausted. It would be advantageous if a convenient arrangement could be organized whereby different potentially-competing suppliers of services can all honor a coupon or gift ticket or similar indicia of value that is denominated not in a monetary value but as as a particular service. It is not possible for the purchaser of a gift ticket for a given increment of services from one establishment to redeem the gift ticket at another establishment for comparable services, because the services are not likely to be of the same value to consumers, or offered at the same price by suppliers. If such a system were envisioned, it would necessarily involve exchanges of cash value and not transactions for a given increment of services regardless or where it is obtained. A gift ticket system might be envisioned where one can buy a gift ticket for an incremental entertainment service (a single movie showing, for example), but if that gift ticket was to be redeemable at any of a plurality of competing different movie theaters, some provision would be needed to account for the fact that some theaters are more comfortable, have larger screens and better sound systems and consequently have higher ticket prices than others. Such an arrangement would not likely be practical, or at least would be less practical than using cash currency, and would require a network of behind-the-scenes fund transfers in varying amounts per transaction, between establishments at which the gift tickets are sold to customers and establishments at which the customer redeems the tickets for more or less expensive entertainment services. On the other hand, one could issue gift tickets for an incremental amount of money, leaving it to the consumer to decide where to expend the gift ticket, either wholly or in some successive number of transactions that each represent less than the full initial cost of the gift ticket. Gift tickets can resemble debit cards and be presented by customers for deduction of an incremental monetary value in exchange for goods or services of that cost. It is known to have the representation of value carried on the card itself (e.g., in the case of a “smartcard” having security aspects). Alternatively, it is known to have the card carry a serial number or address associated with a record stored in a database in communication with points of sale. These arrangements also require behind-the-scenes transfer of funds among the entities selling the cards, perhaps the customer, and the entities at which the card is redeemed for goods or services. It is known that credit cards can be issued that may be selectively limited to certain vendors, either by the users (to limit purchases by their children or others to whom the cards are lent) or by corporations (for example to employees' limit meal and entertainment expenses to certain establishments). See Cohen, U.S. Pat. No. 6,422,462 “Apparatus and Methods for Improved Credit Cards and Credit Card Transactions.” Such cards are still redeemable, however, for the cash value of purchases made and the users are still responsible for paying for transactions on an as-used basis. An arrangement that requires such a network of funds transfers is actually already in place. Credit card systems including Visa, MasterCard, Discover, American Express, etc., deal with goods/services providers across the board. They are available for the most part to any customer and to any supplier. However, existing credit card systems work because there is a medium of exchange, namely dollars and cents (or other currencies), that is the same as to all suppliers and all possible goods and services. There is no practical way in which to supply a given service, such as a round of golf or a theater ticket, that is free of association with a particular supplier and might be redeemed by the customer at any of a plurality of possible suppliers, even though their pricing may differ, without relying on a backup funds transfer network associated with the point of sale. SUMMARY OF THE INVENTION An inventive system and method arrange for prepayment by a customer of a predetermined sum for indicia such as a one-time-use gift ticket. The ticket is redeemable for a particular incremental quantity of services, as opposed to a cash value. The ticket is redeemable at any of a plurality of different providers that offer services that might be more or less similar but that qualify as the stated sort of services. The system and method are particularly applicable to personal services, entertainment services and similar quantifiable services, e.g., a movie pass (at any participating theater), a round of golf (at any participating golf course), a spa treatment (at any participating spa), etc. The providers are independent entities that determine the nature of their own offerings and set their own prices. The gift ticket issuer enlists a number of suppliers of services to be obtained by redemption of the ticket for services, each having offerings that have character, terms and pricing arrangements that are approximately equal but may differ up to some threshold. Enlisted service providers agree to participate in the program and agree to accept the prepaid gift ticket as a payment method. According to an inventive aspect, the enlisted service providers are not required to accept some standard or negotiated amount that is less than their regular price for services of the type that are delivered. Instead, the service providers accept for payment one time use tickets and process the sale to the customer over an existing credit card network or as some other financial transaction (including such instant payment systems as Pay Pal, which allows secured payment directly out of an existing bank account) in which the account that is debited is the account of the entity that issued the one-time-use ticket. Gift tickets are sold through sales outlets, through the Internet, by telephone or in large blocks to institutional purchasers. Participating merchants whose services may be redeemed through the gift ticket system can also be empowered to sell the tickets. The tickets can be retail items of purchase that are activated at the point where the tickets are sold to customers. The customers can use the gift tickets to redeem a stated increment of services for themselves or can present the ticket as a gift. The system is particularly applicable for use in giving gifts or employee awards or incentives, because the emphasis is wholly on redemption for the services and not on redemption of a given cash value. Gift tickets each contain a unique identification code and are loaded with a predetermined value identified as a one-time use at any customer-chosen one of the service providers who have agreed to participate and who provide the pertinent goods or services that are identified when the ticket is sold. When a ticket is sold, it is activated by the seller, for example by scanning a bar code associated with a uniform product code or by swiping a magnetic strip on the ticket itself, and notifying a ticket information manager of its sale. At that time, the unique identification code of the ticket is noted in a memory file by the ticket information manager. A predetermined portion of the sale price (i.e. less any service fee to the vendor) can be transferred by the vendor to the ticketing program manager at the time of ticket activation. Another alternative is that the entire purchase price is credited to an account maintained by or for the ticketing program manager who then regularly compensates the vendor for its participation, either on a flat-fee basis or as some function of the number of tickets sold, including perhaps added incentives at various sales level thresholds. Gift tickets sold over the Internet or by telephone can be mailed in an activated state or can employ security features requiring the purchaser to activate the ticket (by Internet or telephone) upon receipt, for example, by repeating a code that was given to the purchaser at the time of the sale or by repeating a password determined by the purchaser at the time of sale. The ticket can be purchased by the ultimate user or advantageously is given by the purchaser to the end user, for example as a gift, an employee or sales incentive award, a premium item or the like. The gift ticket holder presents the ticket for redemption of the particular service from one of a plurality of agreed service providers. The identities of the agreed service providers can be stored in an inclusion table that is employed by a ticket information manager. The service provider verifies the ticket's validity by checking with the ticket information manager that the ticket's unique identification code is valid and that the ticket has been activated, in a transaction that is much the same as a credit card authorization, which can use the same point of sale network communications as a credit card transaction. According to another aspect, although the gift ticket is issued as a one-time-use item, purchasers can choose to add incremental value to upgrade the ticket at the time of purchase or prior to redemption. This feature has two main applications. With the capability of adding an incremental value, it is possible to apply the invention to services of a given kind (such as a round of golf, for example) that have more than some predetermined threshold difference in value that prevents them from being peers. Thus, the invention can be applied to an arrangement in which 18 holes at an international golf course such as Pebble Beach or the Masters' course in Augusta, for example, can be regarded as distinct services from less prestigious local golf courses that represent the norm. The customer can purchase an upgrade (or several incremental upgrades if more than one is needed for a particular provider) if desired, to the higher quality level in the same category of “a round of golf,” which can be redeemed at any of the venues that fall into the higher classification. Alternatively or in addition to providing upgrades for moving upwardly between two or more classes of a given service that might render two alternatives as peers, the holder of a ticket can be permitted to obtain an upgrade that arranges a ticket issued for one person for a given class of services to be redeemable for more than one person, within the same class of services. Upgrades as described can be purchased in a manner similar to the initial transaction at which the ticket was originally offered and sold. Alternatively, sales of upgrades can be made in various other ways, such as through an Internet web site with the use of a credit card or by touch tone telephone through an Interactive Voice Response system connected to the ticket information manager's data storage system. It is an aspect of the system and method that the purchase price of the gift ticket is fixed, but the ticket holder can redeem the ticket at any of a plurality of providers of a given service, even though the service providers may normally assess different prices. The service providers are credited in the redemption process with their agreed payment price from the ticketing program manager, so that the provider is paid in a normal manner when a ticket user redeems a ticket for a service. In this way, ticket holders are fully as welcome at the provider's establishment as a customer that might remit cash currency when obtaining the same service. In one embodiment of the system, the ticket is recognized by an existing credit card system such as American Express, Visa, Master Charge, Discover, etc. (particularly, Discover, which currently has the capability to distinguish among vendors in an inclusion list), and can be swiped in existing point of sale terminals, thus allowing for familiar use by the service provider and instant payment to the service provider's account. The service provider is credited for the price of its services in the usual manner of a credit card network, but unlike the usual credit card transaction, a charge is not levied against the user's account, but is debited against an account held by the ticketing program manager. A system is also disclosed to implement the marketing, sale, redemption and account management of a one-time-use gift ticket for prepaid entertainment or personal services. The above aspects and features of the invention will be better understood from and are disclosed in further detail by the following detailed description of certain preferred embodiments of the invention, provided in connection with the accompanying drawings, forming a part of this written description. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate preferred embodiments of the invention as well as other information pertinent to the disclosure, in which: FIG. 1 is a stylized block diagram overview of a prepaid services system according to the invention; and, FIG. 2 is a flow diagram illustrating steps of an exemplary embodiment and method of administering a prepaid services system. DETAILED DESCRIPTION Referring to FIG. 1, a stylized overview of a prepaid services system, 10, is provided. As described herein, the prepaid services system includes seven primary parties: seller 20, purchaser 30, ticket user 35, ticket information manager 70, service provider 80, financial network and ticketing program manager 95. Referring to the flow diagram of FIG. 2, at step 100, a ticketing program manager 95 desiring to implement the one-time-use gift ticket system of the invention, especially for a particular type of entertainment or personal service but also potentially for sale of goods, enlists a plurality of providers 80 of one or more substantially comparable services. The ticketing program manager 95 negotiates if necessary with the providers to honor the one-time-use ticket 40 according to the procedures described herein, namely to accept the ticket in exchange for provision of the provider's regular services and to seek remuneration for such services from the system maintained by or for the ticketing program manager. It is advantageous for the ticketing program manager who enlists the service provider to bring the provider on as a member of a common group enterprise including, for example, advertising the enterprise and the provider's membership in the enterprise and the like. Likewise, membership in the enterprise can benefit individual providers, through additional advertising, access to new clientele and association with a product (the one-time-use ticket) that may be promoted as having a certain desirable cachet in and of itself. Additionally, it is desirable that the service providers accept the ticket at all times they are open, so that a “no-blackouts” feature of the gift ticket will enhance its acceptance in the marketplace and add to the desirability of receiving such a pass as a gift. However, it is not strictly necessary for the provider to undertake any particular responsibilities other than to provide the same services to gift ticket users as the provider provides to regular cash customers. In this exemplary illustration of the invention, plural service providers 80 all provide at least one same stated service or article of goods, for example a round of golf, a day's worth of skiing or treatment at a health spa or the like. A broad network of providers of like services who accept the one-time-use ticket improves the marketability of the ticket, since the ability for the user to select among a variety of convenient providers is a desirable feature and one which differentiates the ticket in the present invention from ordinary gift cards or other indicia redeemable only at the retailers from whom it was purchased. It is also expected that the various providers will provide somewhat different services and may assess different charges, up to a threshold of difference within which the providers are considered to provide the “same” service as authorized and redeemable by presenting the one time use gift ticket. Therefore, while the particular service for which a ticket is to be used is nominally the same service for that series of ticket (i.e., for tickets sold for redemption for a uniquely named or described service), the service providers need not all agree to provide identical services or to charge a dictated price for their services. Within the threshold of comparable pricing, differences in services can be accommodated owing to such factors as specific service component differences, location, prestige and quality, or other differences, as well as arbitrary consumer preferences. It is an inventive aspect of the subject system and method that service providers are not required to each accept identical payment value for their services, despite the fact that the gift ticket is sold for a given price and is redeemable for such services at any of the service providers. The ticketing program manager sets the price charged by seller 20 for sale and activation of the ticket, so as to accommodate variations in actual service provider prices. One way to do this is to set the ticket price in view of the most expensive of all of the service providers, plus any service fee collected by the ticketing program manager. Another method, that advantageously allows a lower ticket price, and which can be expected to improve sales, is to set the ticket selling price near to the average charge incurred by all users of the service providers, plus costs of operating the system and a reasonable return to the ticketing program manager. Costs of operating the system can include items such as a fee to the ticket information manager for maintaining a processor to handle ticket information data storage and verification and validation of tickets and costs associated with the financial network, which, might be a credit card network, in which case the credit card company might receive a portion of the sale price. That is, the ticket selling price should be set and/or periodically adjusted so that the use of the tickets integrated over all the users and providers, has a sufficient surplus selling price over the average cost of the service (which may or may not be the same as the average provider price, given that users may frequent certain providers more than others), to provide at least a modest return on investment to the ticketing program manager. The ticket selling price is determined so that any overage that accumulates when a ticket is used to obtain the service from providers whose services are priced at less than the ticket selling price is balanced against the shortfall that arises when a ticket is used to obtain the service from providers whose services are priced higher than the ticket selling price. This calculation advantageously takes into account the extent to which users may prefer to patronize certain providers over others (e.g., providers that are perhaps more prestigious, that advertise more, that have been in business longer or that have locations that are convenient to a larger number of users). The calculation also provides for a return to the ticketing program manager over a break-even number. After the service provider relationships have been established (step 100) or while that is occurring, the ticketing program manager 95 establishes relationships with existing sales outlets (step 110) who will sell the one-time-use tickets. The sellers 20 have point of sale terminals 50 connected to an existing network 60 that will allow fast, efficient communication with the ticket information manager 70. This communication is desirable for the transfer of the information required to initialize a ticket once it has been purchased. If the existing network is connected to a financial network 90, such as that maintained by a credit card company, this can also facilitate the automatic transfer of funds between the sellers 20 and the ticketing program manager 95 and between the ticketing program manager and service providers 80. For example, the credit card company can maintain an escrow account for the ticketing program manager, into which funds are transferred from the sellers and from which funds are withdrawn to pay service providers. By using an existing credit card network as the financial “rail” for the system, funds transfers can be managed with minimal day-to-day involvement from the ticketing program manager. While the use of an existing credit card network as the communication network carries certain advantages it is also possible for the required communications to take place over an Internet connection (for example to a secure web page hosted by the account manager) or a telephone connection to either “live” operators or an Interactive Voice Response system connected to the ticket information manager's (70) data storage equipment. In one exemplary embodiment, the ticket information manager 70 has a communications link or other access to a financial network 90 which is a credit card provider's network. When a ticket is swiped on a point of sale terminal 50 at either the seller's end or the service provider's end, the credit card network will communicate with or otherwise access the ticket information manager's equipment. All ticket verification or validation and approval of service providers is handled directly by the ticket information manager. The ticket information manager simply returns an accept or reject message to the credit card network, which then either causes the transaction to be processed at the point of sale terminal or not. In an alternative embodiment, the gift ticket issuer can be a commercial organization other than a seller, with communications equipment or the like to activate the ticket through communications with the ticketing program manager. Once relationships with the sellers 20 and service providers 80 are established, the ticketing program manager distributes one-time-use tickets (step 120). Preferably the tickets are distributed at first in an un-initialized state, namely functional but not yet validated for use. A validation process includes placing suitable codes or notations on the tickets or storing codes in the tickets or elsewhere in a data storage medium that is accessible over a communication network. These codes can be checked when determining whether to permit use of the tickets. In one embodiment, the tickets have a preprinted unique identification code and a magnetic strip or other means of recording information. The strip or other means can be prerecorded with a unique or at least substantially unique identification code for each ticket. The unique identification code may be an alphabetic code, a numeric code, an alpha numeric code, or other appropriate identification code capable of uniquely identifying an individual ticket, and perhaps also identifying the related type of service (e.g., golf, spa, etc.). In an alternate embodiment, the tickets do not have a preprinted or prerecorded identification code, but do contain a recordable medium such as a magnetic strip or an electronic storage device, which may be loaded with a unique code preliminarily or may have an area in which such a code is inserted as a part of the initialization procedure. According to an advantageous aspect, the issued ticket is configured and formatted with certain indicia characteristic of a standard credit card. This can include, without limitation, printed or embossed account identification numbers, a magnetic strip or on board integrated circuit memory, a one or two dimensional optical bar code, etc. The information can be prerecorded or at least partly recordable. Two or more redundant means for storing the same information, such as an account number or the like, can be provided for data entry in different optional ways, of the different storage techniques can be used for information that is otherwise cross referenced. Advantageously, the ticket has sufficient information carried thereon to permit use of the ticket substantially in the same physical manner as a standard credit card, namely using equipment conventionally provided at a point-of-sale terminal 50 (scanners, magnetic strip swipe readers, keyboards, etc.). In one embodiment, the ticketing program manager has reserved for itself a series of digits or numbers or number combinations in a standard credit card format that are unique to the account manager and identify one or more accounts associated with the ticketing program manager. Initialization and validation steps, which are processed by a ticket information manager 70 can be undertaken over an existing communication network 60, which advantageously is a network that processes conventional credit cards, or can be another public or private data communication network. Other types of communication devices may be used instead of or in addition to a standard point-of-sale terminal programmed to handle credit cards, so long as the device is capable of communicating sufficient ticket information over an operable communications network to effect the steps as described herein. For example, in another form of the invention, the ticket information can be transmitted between the seller and the ticket information manager by telephone either by voice in association with a live operator or through a telephone keypad to an Interactive Voice Response system. The one-time-use ticket proceeds through several steps associated with initial issue, sale (preferably with validation concurrently upon sale), and later presentation as an identification of value used to present remittance for a service. At step 130, the purchaser 30 selects a gift ticket for purchase and pays the seller 20 some agreed purchase price 31. This transaction can be a conventional retail, wholesale or other transaction in which one or more tickets are exchanged for cash or credit or other remuneration. At step 131, the seller 20 activates the ticket, preferably including transmitting an identification code that is or becomes associated with the ticket (e.g., is at least partly read from or written onto the ticket). The identification code is at least substantially unique to the ticket and is transmitted over the existing communications network 60 to the ticket information manager 70 or to a data store associated with the ticket information manager 70. If the system is such that the ticket already has a preprinted or recorded identification number, the ticket information manager compares this number with the numbers of tickets that it has previously distributed to sellers as one step in determining validity. If the ticket has a valid number that has not already been processed, the ticket information manager records the ticket's number, noting for example in a data memory that the ticket has now been purchased and should be authorized for use. Other information is also preferably recorded, including at least the purchase price and the date of the sale transaction (step 132). The ticket information manager preferably acknowledges by communication back to the seller that the ticket is valid and now has been initialized (step 133), although the acknowledgement can be deferred or accomplished off line. The seller then accepts payment 31 from the purchaser 30 (who might or might not be the ultimate ticket user). At some point, the seller transfers payment 21 to the ticketing program manager, preferably through a financial network such as a credit card network. If a credit card network is used, funds can be automatically transferred to an escrow account maintained with the credit card company for the ticketing program manager. Although the seller could have previously paid the ticketing program manager in full for the tickets and then resells them to customers, it is preferable that payment to the ticketing program manager's escrow account is made from funds received from the customer. Therefore, payment is transferred to or for the benefit of the ticketing program manager when payment is tendered by the customer. The payment to the ticketing program manager (or it's escrow account) is the payment tendered, less a portion of the sale price that is due to the seller (step 134) in consideration of making the sale. In an embodiment wherein the communication network 60 is an existing credit card network, credit can be transferred immediately to the ticketing program manager's account. In another embodiment, the initialization process can take place over the Internet, e.g., via a secure web page hosted by the ticketing program manager or another party providing account transfer services. For example, payment to the ticketing program manager's escrow account can be effected through available Internet payment mechanisms such as Pay Pal, which provides for value transfer to user's accounts. Otherwise, the seller 20 can remit funds owed to the ticketing program manager 95 on an invoiced or other basis. Because the initialization of the ticket (steps 131-133) must be done through the ticket information manager 70, an exact, up-to-date record is maintained of how many tickets each seller has sold, and at what price. This facilitates accountability and correct payment to the ticketing program manager or into its escrow account. Once a customer has purchased a ticket, the ticket may be used by the purchaser 30 or by someone to whom the purchaser has conveyed the ticket, for example as a premium or as a gift for redemption, etc. The ticket is used as a representation of value used as remittance at any of the agreed service providers 80. (Inasmuch as the user 35 might or might not be the same party as the purchaser 30, for the purpose of this description, the term “user” should be construed to encompass an initial purchaser or anyone to whom the purchaser has conveyed the ticket.) A ticket user 35 presents the ticket to a service provider at step 150 in order to redeem the indicated service. At step 151, the service provider preferably verifies the validity of the ticket by data transfer with the ticket information manager 70 over the communications network 60. If the communications network is one that is maintained by a credit card provider, the credit card provider's equipment would recognize the unique identification code as being not an ordinary credit card but a one-time-use ticket and would contact the ticket information manager to perform verification of both the service provider's inclusion in the program and the validity of the individual ticket. As a first check, the ticket information manager will verify that the service provider is among those who have agreed to accept the tickets. (Step 152). This may be accomplished by the storage of an inclusion table by the ticket information manager. If the communications network is also a credit card network, the initial screening for whether a service provider is listed in an inclusion table can also be made by the credit card service provider. The unique identification code associated with the ticket is then transmitted to the ticket information manager. At step 153, the ticket code is compared with a list of codes stored in a data base maintained by (or for) the ticket information manager, namely a list of valid ticket codes for initialized but as-yet-unused tickets. If the ticket code is valid and the ticket has not yet been used, the ticket information manager returns a message to the service provider (via the credit card network if employed as part of the system) that the ticket is valid, indicating that the user may redeem a single use of the service provider's services, such as the aforementioned round of golf, day of skiing or treatment at a health spa or the like. The ticket information manager then records data referenced to the ticket code to represent that the ticket has been used, so that the ticket may not be used validly again (step 154). By communicating to the service provider 80 that the ticket is valid, the ticket information manager 70 basically indicates that the ticketing program manager 95 will remit payment 81 to the service provider 80 the purchase price of the service for which the ticket user 35 has presented the ticket. If a credit card provider is serving as the financial network and the communications network, the ticket information manager can signal the credit card provider to release funds from an escrow account maintained for the ticketing program manager directly to the service provider's account. To facilitate validation, it is possible for a service provider that offers various services to report to the ticket information manager that a particular service is being redeemed, whereby the ticketing program manager can account for the amount to be remitted. Finally, the ticket information manager sends a notification to the financial network that a ticket has been redeemed, at which point the financial network provider transfers payment 81 from the ticketing program manager's account to the service provider's account. (Step 155). In the embodiment wherein the communications network 60 is (or links with) an existing credit card network, credit for the funds may be transferred from the ticketing program manager (or its escrow account maintained by the credit card network) to the service provider's account immediately in the same way as a credit card transaction, but customer is not privy to the accounting details of price and the like, and preferably is not required to present identification or sign receipts or the like, because the monetary transaction is between the ticketing program manager and the service provider. Although a credit card network can be used, the communications network can be another public or private data communications network, such as an Internet connection to a web page hosted by (or for) the ticket information manager or alternatively by the ticketing program manager. The ticketing program manager can transfer funds to the service provider using a variety of Internet-based services, such as Pay Pal, Bill Point, etc. Otherwise, the ticketing program manager can make payment by check or other means to service providers on a periodic basis to account for the number of users that have used that service provider's services since last payment. It will be recognized that the separate functional blocks depicted in FIG. 1 as ticket information manager 70 and ticketing program manager 95 may be performed by the same entity. It should be recognized that an escrow account cam be maintained either by the ticketing program manager as depicted in FIG. 1 or by the financial network 90 on behalf of the ticketing program manager. If, at step 153, the ticket information manager determines that the ticket does not have a valid identification code, or has a code for a ticket that has already been used once, then a message is returned to the service provider indicating that the ticket is not valid and that the service provider should not accept the ticket as payment for services. A similar message would result if, at step 152, the ticket information manager does not recognize the service provider as one who has agreed to participate in the prepaid leisure activity services system. That is, the service provider is not listed in the ticket information manager's inclusion table. It is an aspect of the invention that the gift ticket carries information and functions as a means for the user to obtain and remit for an incremental service, as opposed to an incremental sum of money. The various service providers may actually charge different amounts for services. A given service provider may assess different charges at different times. Likewise the retailer that originally sold the ticket to the customer may have more or less of a markup. From the user's standpoint, the system treats the ticket as the means to provide an increment of services (or possibly goods) apart from these pricing considerations, which is advantageous. At step 160, after the system has been in operation for some period of time, the ticketing program manager can compare and reconcile any overage/underage on proceeds received on tickets presented for higher or lower priced service providers and/or sold by sellers with higher or lower markups, and adjust pricing and payment strategies or provider membership arrangements, if necessary. These differences are absorbed and averaged by the ticketing program manager, who can make certain decisions about how the system is run and priced. For example, the ticketing program manager may decide based on experience to adjust the sale price of future tickets or may determine that certain sellers and/or providers will or will not become or remain active, competition and supply and demand causing the market to reach an equilibrium. However, because the gift ticket represents credit for a service and not a monetary value to the users, a change in price for new ticket purchases will not affect the redeem-ability of tickets already purchased. In another embodiment of the invention, the purchasers or ticket users are provided a capability to add a limited amount of incremental value to the ticket (an upgrade), either at time of purchase or at any time after purchase and prior to redemption of the ticket for services (step 140). The addition of incremental value can be employed at least two ways. The feature incorporating the addition of incremental value can apply to allow use of the ticket at service providers whose services are priced significantly higher than the initial value of the ticket, e.g., services that are substantially different and that might be expected to be priced very differently from other services of the same category. If a user wants to redeem the ticket at one of these service providers, incremental value must first be added to the ticket. Incremental value need not necessarily be an integer multiple of the ticket's initial value, but can be a fraction of the initial value. However, it is a particular feature of the invention that the ticket always reflects incremental values, or credits, to the user, and not monetary value. While the ticket information manager may store for each ticket data representing the actual monetary value that has been purchased by the ticket user, any features that allow the user to retrieve information about the ticket (such as Interactive Voice Response or Internet access described more fully below) will always return incremental credit information and not monetary value to the user. This distinction reinforces the premise that the ticket represents the ability to redeem a service from agreed providers regardless of the cost of that service. In another method, additional incremental value is used to allow the user to redeem the ticket to accommodate providing the service to additional people at the time of redemption, for example, so that the user and a guest or guests can pay for all of their rounds of golf on the ticket. According to a preferred arrangement, a ticket with additional incremental value, like an initial ticket, cannot be presented on more than one occasion. Instead, the ticket is marketed and used as a one-time-use ticket for a given service, and adding increments refers to adding (or perhaps changing) the service that is provided when the single use is redeemed by one or more associated users. It will be recognized that the incremental upgrades for higher-priced service providers and for allowing additional guests can also be combined to allow either or both options as part of the method. The feature incorporating the addition of incremental value can apply to allow use of the ticket at service providers whose services are priced significantly higher than the initial value of the ticket, e.g., services that are substantially different and that might be expected to be priced very differently from other services of the same category. If a user wants to redeem the ticket at one of these service providers, incremental value must first be added to the ticket. Incremental value need not necessarily be an integer multiple of the ticket's initial value, but can be a fraction of the initial value. However, it is a particular feature of the invention that the ticket always reflects incremental values, or credits, to the user, and not monetary value. While the ticket information manager may store for each ticket data representing the actual monetary value that has been purchased by the ticket user, any features that allow the user to retrieve information about the ticket (such as Interactive Voice Response or Internet access described more fully below) will always return incremental credit information and not monetary value to the user. This distinction reinforces the premise that the ticket represents the ability to redeem a service from agreed providers regardless of the cost of that service. In another embodiment of the invention, a user can purchase additional incremental value directly from the ticketing program manager, or an agent of the ticketing program manager. This can be implemented in various ways, including via telephone or the Internet. A telephone-based method for allowing purchase of additional incremental value can be implemented either with “live” operators who respond to users' telephone calls or with Interactive Voice Response (IVR) equipment. In a live operator system, the operators will have access to the ticket information manager's database of ticket (and, if applicable, user) information and can search, access and modify the information via a computer terminal or like device. Another option provides for the ticket information manager (or, alternatively the ticketing program manager) to maintain an (IVR) system that is entirely computerized. Users who call to add additional value to their tickets will do so by entering numbers on the telephone keypad, in response to computer-generated messages, such as “Please enter 1 to add value to your ticket. Now enter your 16 digit ticket number followed by the pound sign.” Ticket information can be read back to the user with voice simulation or prerecorded messages stored as a part of the IVR system. It is also possible to combine live and IVR systems so that users have the option of performing the transaction with a person or a computer. A further embodiment of the system provides for Internet-based account management. The ticket information manager (or, alternatively the ticketing program manager) can maintain computers connected to the Internet and programmed to allow users to access and update ticket information or upgrade ticket value via a web page. The web address can be preprinted on the tickets or on the packaging with which the tickets are sold. Upon entering the ticket information manager's secure web site, users will be asked to enter the unique identification code of their ticket. The ticket information manager's computer will check the ticket number against the database of valid ticket numbers and if the number is valid, allow the user to add value to the ticket, and pay for the transaction through a standard credit card. The ticket information manager's database will then be updated to reflect the additional value added to the user's ticket and credit will be added to the ticketing program manager's account. In an Internet-based option, the user can also use the Internet to simply verify ticket value or expiration date and once connected to the ticket information manager's web page also search for service providers in the user's locality, or in a travel destination where the user expects to redeem the ticket. This feature gives added value to service providers since the web access gives the service providers an opportunity to provide web page links with customized advertising or other information in addition to standard information provided by the ticketing program manager's web site. In any embodiment of the invention that allows user retrieval of ticket information, the actual cash value that has been purchased in connection with the ticket is never available to the user, only the number of incremental credits loaded onto the ticket. Those skilled in the art will recognize that the ticket information manager's database can be set up to store information beyond the ticket number and value associated with a ticket. For example, user identification information such as name, address and e-mail address can be stored at the time a user purchases a ticket. Storage of this information would, for example, allow the ticketing program manager to replace a lost ticket upon presentation by the user of such personal identification information. The ticket information manager can search its database for a user's name and determine whether the user's ticket has been redeemed. If the ticket has not yet been redeemed, then the lost ticket number can be canceled and a new ticket issued to the user. This transaction could be implemented either in person through a seller or with the ticketing program manager (or, alternatively, the ticket information manager) via telephone or the Internet as described above. Recordation of user information can also provide a valuable feature to service providers who, if given access to such information (either for a fee or by other agreement with the ticketing program manager) can access that information for marketing purposes, and can target marketing specifically to users who have redeemed their tickets at that particular service provider. In the case where a ticket can have additional incremental value added, part of step 153 would include not only verifying that the ticket is valid, but determining the total value of the ticket. Again, the ticket's value as seen by a user is not intended to be in monetary units, but incremental credits. For example, a ticket may be initialized with one credit at time of sale (a base value), and be valid for a single use at all service providers who accept the base value. Additional credits can be fractions of the base value. For example, additional increments might be one quarter of the initial value. A user can then purchase four additional increments to take a guest if that is a feature of the system, or might purchase only the number of incremental credits to be able to use the ticket at a service provider who does not accept the base value of the ticket. In this embodiment of the invention, the service provider will verify the ticket's validity and its value at time of redemption. Because the ticket is a one-time-use ticket, any additional value on the ticket that exceeds that needed for the user to redeem the service will be lost to the user. | <SOH> BACKGROUND OF THE INVENTION <EOH>Goods and services are typically obtained in exchange for payment and the payment might be rendered in various ways and in various amounts, such as by tender of cash currency, funds transfer between accounts, debit card purchase and exhaustion, credit arrangements involving future payment, barter or various other techniques. The particular goods or services that a customer might obtain from different providers differ. The reputations of providers differ. The manner of providing services, such as the time of day or as a function of demand or other aspects also differ. Importantly, the providers also demand different prices. The differences between available offerings of goods and services generally boil down to differences in the costs and benefits of available goods and services that consumers have the option to choose. The costs and benefits of the possible choices are judged and compared by customers when making purchasing decisions. The customers seek the greatest benefit per unit cost and are free to make selections among a variety of different providers' offerings and terms, or even to substitute one type of service for another according to the customer's needs. The relative merits and different options are perceived differently by different consumers, such that some consumers are willing to pay more or less than others for particular aspects of goods or services. The confluence of offerings (including what is offered and the terms of payment) with the selections made by consumers is the nature of the market of supply and demand by which resources are allocated among consumers in a market economy. Not all consumer transactions are classic exercises of supply and demand wherein the customer has the utmost control and choice among differing alternatives with incrementally different costs and/or different pricing and payment arrangements. One example is a vendor's prepaid gift indicia, which can take various forms ranging from an authorized numbered slip bearing the vendor's name and a dollar amount to plastic cards bearing the vendor's logo and having a magnetically readable strip with a predetermined dollar value, each redeemable at the vendor's sales outlets. A prepaid gift indicia is generally issued by a particular retailer and can only be redeemed at that retailer's facilities. In this situation, the person who purchases the gift indicia may exercise a degree of choice, but the person who redeems it (typically the recipient of the gift) has no choice except to use the issuing retailer as the provider. Inasmuch as the issuer and the provider are the same entity, the issuer/provider has full control of the extent to which the selling price of the gift card corresponds to the offering price of the goods or services that are delivered. It is conceivable that the issuer/provider may include a premium or discount to encourage patronage and/or purchase of gift indica, but within the control of the issuer/provider, the goods or services are provided in exchange for an amount that is related to the issuer/provider's pricing schedules. It its known that providers of personal entertainment and sporting services, can issue a gift ticket that represents an incremental cash value or an incremental quantity of their services. This is possible because pricing and terms upon the sale of the gift ticket are controlled by the same party that controls the nature, quality and delivery terms of the services. As a result, the issuer/provider can issue a gift ticket for a given cash value or for a given increment of services. Thus a gift ticket or coupon might be granted for one pass to a matinee show or one Saturday afternoon bowling game, presumably with the ticket priced at an amount related to the pricing of the associated service. If the gift ticket is not defined as equal to a given service and/or if the issuer offers different services at different prices, then the gift ticket is denominated as a cash value and the user is entitled to deduct from the value on the ticket when paying for services, until the value associated with the ticket is exhausted. It would be advantageous if a convenient arrangement could be organized whereby different potentially-competing suppliers of services can all honor a coupon or gift ticket or similar indicia of value that is denominated not in a monetary value but as as a particular service. It is not possible for the purchaser of a gift ticket for a given increment of services from one establishment to redeem the gift ticket at another establishment for comparable services, because the services are not likely to be of the same value to consumers, or offered at the same price by suppliers. If such a system were envisioned, it would necessarily involve exchanges of cash value and not transactions for a given increment of services regardless or where it is obtained. A gift ticket system might be envisioned where one can buy a gift ticket for an incremental entertainment service (a single movie showing, for example), but if that gift ticket was to be redeemable at any of a plurality of competing different movie theaters, some provision would be needed to account for the fact that some theaters are more comfortable, have larger screens and better sound systems and consequently have higher ticket prices than others. Such an arrangement would not likely be practical, or at least would be less practical than using cash currency, and would require a network of behind-the-scenes fund transfers in varying amounts per transaction, between establishments at which the gift tickets are sold to customers and establishments at which the customer redeems the tickets for more or less expensive entertainment services. On the other hand, one could issue gift tickets for an incremental amount of money, leaving it to the consumer to decide where to expend the gift ticket, either wholly or in some successive number of transactions that each represent less than the full initial cost of the gift ticket. Gift tickets can resemble debit cards and be presented by customers for deduction of an incremental monetary value in exchange for goods or services of that cost. It is known to have the representation of value carried on the card itself (e.g., in the case of a “smartcard” having security aspects). Alternatively, it is known to have the card carry a serial number or address associated with a record stored in a database in communication with points of sale. These arrangements also require behind-the-scenes transfer of funds among the entities selling the cards, perhaps the customer, and the entities at which the card is redeemed for goods or services. It is known that credit cards can be issued that may be selectively limited to certain vendors, either by the users (to limit purchases by their children or others to whom the cards are lent) or by corporations (for example to employees' limit meal and entertainment expenses to certain establishments). See Cohen, U.S. Pat. No. 6,422,462 “Apparatus and Methods for Improved Credit Cards and Credit Card Transactions.” Such cards are still redeemable, however, for the cash value of purchases made and the users are still responsible for paying for transactions on an as-used basis. An arrangement that requires such a network of funds transfers is actually already in place. Credit card systems including Visa, MasterCard, Discover, American Express, etc., deal with goods/services providers across the board. They are available for the most part to any customer and to any supplier. However, existing credit card systems work because there is a medium of exchange, namely dollars and cents (or other currencies), that is the same as to all suppliers and all possible goods and services. There is no practical way in which to supply a given service, such as a round of golf or a theater ticket, that is free of association with a particular supplier and might be redeemed by the customer at any of a plurality of possible suppliers, even though their pricing may differ, without relying on a backup funds transfer network associated with the point of sale. | <SOH> SUMMARY OF THE INVENTION <EOH>An inventive system and method arrange for prepayment by a customer of a predetermined sum for indicia such as a one-time-use gift ticket. The ticket is redeemable for a particular incremental quantity of services, as opposed to a cash value. The ticket is redeemable at any of a plurality of different providers that offer services that might be more or less similar but that qualify as the stated sort of services. The system and method are particularly applicable to personal services, entertainment services and similar quantifiable services, e.g., a movie pass (at any participating theater), a round of golf (at any participating golf course), a spa treatment (at any participating spa), etc. The providers are independent entities that determine the nature of their own offerings and set their own prices. The gift ticket issuer enlists a number of suppliers of services to be obtained by redemption of the ticket for services, each having offerings that have character, terms and pricing arrangements that are approximately equal but may differ up to some threshold. Enlisted service providers agree to participate in the program and agree to accept the prepaid gift ticket as a payment method. According to an inventive aspect, the enlisted service providers are not required to accept some standard or negotiated amount that is less than their regular price for services of the type that are delivered. Instead, the service providers accept for payment one time use tickets and process the sale to the customer over an existing credit card network or as some other financial transaction (including such instant payment systems as Pay Pal, which allows secured payment directly out of an existing bank account) in which the account that is debited is the account of the entity that issued the one-time-use ticket. Gift tickets are sold through sales outlets, through the Internet, by telephone or in large blocks to institutional purchasers. Participating merchants whose services may be redeemed through the gift ticket system can also be empowered to sell the tickets. The tickets can be retail items of purchase that are activated at the point where the tickets are sold to customers. The customers can use the gift tickets to redeem a stated increment of services for themselves or can present the ticket as a gift. The system is particularly applicable for use in giving gifts or employee awards or incentives, because the emphasis is wholly on redemption for the services and not on redemption of a given cash value. Gift tickets each contain a unique identification code and are loaded with a predetermined value identified as a one-time use at any customer-chosen one of the service providers who have agreed to participate and who provide the pertinent goods or services that are identified when the ticket is sold. When a ticket is sold, it is activated by the seller, for example by scanning a bar code associated with a uniform product code or by swiping a magnetic strip on the ticket itself, and notifying a ticket information manager of its sale. At that time, the unique identification code of the ticket is noted in a memory file by the ticket information manager. A predetermined portion of the sale price (i.e. less any service fee to the vendor) can be transferred by the vendor to the ticketing program manager at the time of ticket activation. Another alternative is that the entire purchase price is credited to an account maintained by or for the ticketing program manager who then regularly compensates the vendor for its participation, either on a flat-fee basis or as some function of the number of tickets sold, including perhaps added incentives at various sales level thresholds. Gift tickets sold over the Internet or by telephone can be mailed in an activated state or can employ security features requiring the purchaser to activate the ticket (by Internet or telephone) upon receipt, for example, by repeating a code that was given to the purchaser at the time of the sale or by repeating a password determined by the purchaser at the time of sale. The ticket can be purchased by the ultimate user or advantageously is given by the purchaser to the end user, for example as a gift, an employee or sales incentive award, a premium item or the like. The gift ticket holder presents the ticket for redemption of the particular service from one of a plurality of agreed service providers. The identities of the agreed service providers can be stored in an inclusion table that is employed by a ticket information manager. The service provider verifies the ticket's validity by checking with the ticket information manager that the ticket's unique identification code is valid and that the ticket has been activated, in a transaction that is much the same as a credit card authorization, which can use the same point of sale network communications as a credit card transaction. According to another aspect, although the gift ticket is issued as a one-time-use item, purchasers can choose to add incremental value to upgrade the ticket at the time of purchase or prior to redemption. This feature has two main applications. With the capability of adding an incremental value, it is possible to apply the invention to services of a given kind (such as a round of golf, for example) that have more than some predetermined threshold difference in value that prevents them from being peers. Thus, the invention can be applied to an arrangement in which 18 holes at an international golf course such as Pebble Beach or the Masters' course in Augusta, for example, can be regarded as distinct services from less prestigious local golf courses that represent the norm. The customer can purchase an upgrade (or several incremental upgrades if more than one is needed for a particular provider) if desired, to the higher quality level in the same category of “a round of golf,” which can be redeemed at any of the venues that fall into the higher classification. Alternatively or in addition to providing upgrades for moving upwardly between two or more classes of a given service that might render two alternatives as peers, the holder of a ticket can be permitted to obtain an upgrade that arranges a ticket issued for one person for a given class of services to be redeemable for more than one person, within the same class of services. Upgrades as described can be purchased in a manner similar to the initial transaction at which the ticket was originally offered and sold. Alternatively, sales of upgrades can be made in various other ways, such as through an Internet web site with the use of a credit card or by touch tone telephone through an Interactive Voice Response system connected to the ticket information manager's data storage system. It is an aspect of the system and method that the purchase price of the gift ticket is fixed, but the ticket holder can redeem the ticket at any of a plurality of providers of a given service, even though the service providers may normally assess different prices. The service providers are credited in the redemption process with their agreed payment price from the ticketing program manager, so that the provider is paid in a normal manner when a ticket user redeems a ticket for a service. In this way, ticket holders are fully as welcome at the provider's establishment as a customer that might remit cash currency when obtaining the same service. In one embodiment of the system, the ticket is recognized by an existing credit card system such as American Express, Visa, Master Charge, Discover, etc. (particularly, Discover, which currently has the capability to distinguish among vendors in an inclusion list), and can be swiped in existing point of sale terminals, thus allowing for familiar use by the service provider and instant payment to the service provider's account. The service provider is credited for the price of its services in the usual manner of a credit card network, but unlike the usual credit card transaction, a charge is not levied against the user's account, but is debited against an account held by the ticketing program manager. A system is also disclosed to implement the marketing, sale, redemption and account management of a one-time-use gift ticket for prepaid entertainment or personal services. The above aspects and features of the invention will be better understood from and are disclosed in further detail by the following detailed description of certain preferred embodiments of the invention, provided in connection with the accompanying drawings, forming a part of this written description. | 20040420 | 20060627 | 20051020 | 69188.0 | 2 | TRAIL, ALLYSON NEEL | SYSTEM FOR MARKETING LEISURE ACTIVITY SERVICES THROUGH PREPAID TICKETS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,827,949 | ACCEPTED | Ozone-assisted bi-layer lift-off stencil for narrow track CPP-GMR heads | A method for forming a bi-layer lift-off mask for use in fabricating GMR read-head sensors with trackwidths of less than 0.1 microns. The mask layers are formed symmetrically on each other, each layer of the mask having a novel dog-bone shape and the lower mask layer being substantially undercut relative to the upper mask layer. The central portion of the lower mask layer forms a narrow ridge that maintains the upper mask layer at a fixed height above a substrate, thereby avoiding problems associated with bi-layer lift-off masks of the prior art. The method of forming the lower ridge requires a carefully controlled undercutting of the lower mask layer, which is accomplished by using an ozone-assisted oxidation process. | 1. A method for forming, on a substrate, a bi-layer lift-off mask having an upper and a lower layer, both layers having a geometrically similar dog-bone shape, the upper layer being symmetrically formed on the lower layer, the lower layer being formed on said substrate and being uniformly undercut relative to said upper layer and wherein said dog-bone shape is characterized by a narrow central linear portion formed between flared distal portions, said central portion of the lower layer being substantially narrower than the central portion of said upper layer and thereby forming a narrow ridge that supports and maintains the central portion of said upper layer at a fixed height above said substrate, comprising: providing a substrate; forming on said substrate a lower layer of PMGI or its derivatives; forming on said PMGI layer an upper layer of radiation-sensitive resist material; exposing a dog-bone shaped region of said radiation-sensitive material with appropriate radiation, the central portion of said region having an initial width and a length; developing said exposed upper layer, said developing process removing all unexposed portions of said layer as well as at least all portions of said lower PMGI layer not directly beneath said exposed layer and producing, thereby, an initial undercut of said PMGI layer relative to said upper layer; performing an ozone-assisted additional undercut process of said lower PMGI layer by placing said layers in the presence of an ozone oxidizing ambient wherein there is an ozone density, an ozone flow rate, an ozone processing time and a processing temperature, said process, thereby, producing a further undercut by a controlled rate of dissolution of the PMGI layer; producing a well controlled undercut of the PMGI relative to the exposed upper layer, the final width, W2, of the central portion of the PMGI subsequent to said undercut being less than the final width, W1, of the upper layer and said PMGI central region forming, thereby, a supporting ridge beneath said central portion of the upper layer. 2. The method of claim 1 wherein said radiation sensitive material is sensitive to exposure by E-beam, X-ray or deep ultraviolet radiation. 3. The method of claim 2 wherein said radiation is deep ultraviolet radiation (DUV) produced by a KrF laser or an ArF laser and said radiation sensitive material is DUV sensitive photoresist. 4. The method of claim 1 wherein the developing process includes a post-bake of the exposed upper layer and the application of a developing solution having a concentration of up to 2.38% of TMAH. 5. The method of claim 1 wherein the ozone-assisted undercut is produced in the absence of a developing solution in an ozone ambient at a density between approximately 50 and 500 grams/m3, wherein the application of ozone is at an ozone flow rate between approximately 5 and 50 liters per minute. 6. The method of claim 1 wherein said process time is between approximately 1 and 3 minutes. 7. The method of claim 1 wherein said process temperature is between approximately 50° and 150° C. 8. The method of claim 1 wherein the length of said central region is between approximately 0.5 and 2.0 microns. 9. The method of claim 1 wherein the final width, W1, of said central region is between approximately 0.04 and 0.3 microns. 10. The method of claim 1 wherein the thickness of said upper layer is between approximately 0.1 and 2.0 microns. 11. The method of claim 1 wherein the thickness of said PMGI layer is between approximately 0.03 and 0.1 microns. 12. The method of claim 1 wherein said substrate is a GMR stack in a CPP, CIP or TMR configuration and wherein said bi-layer lift-off mask is used to pattern said stack forming, thereby, a GMR read sensor having a narrow trackwidth of substantially the width, W1, of said mask. 13. The method of claim 12 further including the use of said bi-layer lift-off mask as a deposition mask to form additional material layers laterally disposed against said GMR read sensor, said additional layers being formed without overspray or fencing and said mask being lifted off said substrate without damage to said GMR sensor. 14. A bi-layer lift-off mask formed of an upper and a lower layer, both layers having a geometrically similar dog-bone shape, wherein the lower layer is symmetrically formed beneath the upper layer and is uniformly undercut relative to said upper layer and wherein said dog-bone shape includes a narrow central linear portion formed between flared distal portions, the central portion of said undercut lower layer being substantially narrower than the central portion of said upper layer forming, thereby, a narrow ridge that maintains and supports the central portion of said upper layer at a fixed height above a substrate, comprising: a substrate; an upper layer formed of radiation-sensitive material that has been exposed to such radiation and developed to form a dog-bone shape, the central linear portion of said shape having a width W1 and a length L1; a lower layer formed of PMGI or its derivatives on said substrate, said lower layer having a dog-bone shape and being symmetrically positioned beneath said upper layer and uniformly undercut relative to said upper layer, the central linear portion of said lower layer having a width W2 that is substantially less than W1 forming, thereby, a ridge beneath the central portion of said upper layer. 15. The mask of claim 14 wherein said radiation sensitive material is sensitive to exposure by E-beam, X-ray or deep ultraviolet radiation. 16. The mask of claim 15 wherein said exposing radiation is deep ultraviolet radiation (DUV) produced by a KrF laser or an ArF laser and said radiation sensitive material is DUV sensitive photoresist. 17. The mask of claim 14 wherein the width, W1, is between approximately 0.04 and 0.3 microns and the length, L1 is between approximately 0.5 and 2.0 microns. 18. The mask of claim 14 wherein the thickness of said upper layer is between approximately 0.1 and 2.0 microns. 19. The mask of claim 14 wherein the thickness of said PMGI layer is between approximately 0.03 and 0.1 microns. | BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to the fabrication of a giant magnetoresistive (GMR) magnetic field sensor in the current-perpendicular-to-plane (CPP) configuration, more specifically to the use of a novel bi-layer lift-off mask to pattern such a sensor having an ultra-narrow track width. 2. Description of the Related Art Magnetic read sensors that utilize the giant magnetoresistive (GMR) effect for their operation must be patterned to produce a required trackwidth. Such patterning is conventionally done using a single photolithographic lift-off mask as both an etching stencil and a deposition mask. The shape of the stencil portion of such a mask permits the necessary trimming of the deposited layers to the required trackwidth and then the mask is used to allow deposition of additional layers (eg. conduction lead layers, biasing layers and/or insulation layers) within the removed regions. If the trackwidth of the read element is to be held below about 0.1 microns, then the prior art methods of forming the prior art masks have notable shortcomings. Han et al. (U.S. Pat. No. 6,493,926), assigned to the same assignee as the present invention and which is fully incorporated herein by reference, discusses several problems associated with prior art lift-off masks in which an upper (stencil) layer of photoresist is formed over a lower, undercut, pedestal, layer. In such mask designs the width of the pedestal layer becomes a critical factor in the proper performance of the mask during the deposition stage. If the pedestal is undercut too much, the upper portion of the mask can collapse prematurely under the weight of deposition residue making a clean lift-off of the mask impossible. On the other hand, if the pedestal is insufficiently undercut, subsequent depositions can build up against the pedestal, called “fencing,” leading to excessive thicknesses of the deposited material and short-circuiting of conductive layers. To overcome the difficulties of forming properly and consistently undercut pedestals and for use in forming trackwidths of approximately 0.5 microns, Han et al. teach the formation of a bi-layer suspension-bridge mask formation, in which there is no pedestal directly beneath the upper portion of the mask, but wherein the upper portion is supported on two pedestals that are laterally disposed beneath two distal ends of the mask. The complete elimination of any support directly beneath the mask thereby avoids the problems associated with insufficient or overly-sufficient pedestal undercut. The formation taught by Han et al. requires that the portion of the mask that would ordinarily be beneath the upper portion be completely removed, so that the upper portion is suspended above the device to be patterned and does not contact it. This object is achieved by forming the pedestal portion of the mask of a layer of PMGI, while forming the upper portion of the mask of a layer of photoresist material. Application of a proper developing solution thereupon dissolves the lower PMGI portion preferentially relative to the photoresist upper portion, removing the PMGI except beneath the end portions where it remains to serve as a support. Fontana J R., et al. (US Patent Application Publication No. U.S. 2002/0167764 A1) also teach the formation of a suspension bridge type bi-layer lift-off mask in which a layer of PMGI (polydimethylglutarimide) polymer is first spun onto a substrate and then a layer of PMMA is spun over the PMGI layer. An e-beam is then used to form a mask pattern in the upper layer by developing the upper layer and the PMGI layer is dissolved to form the undercut region. The method taught by Han et al. was applied to patterning trackwidths on the order of 0.5 microns. Attempts to apply the method of Han et al. to produce trackwidths below 0.1 microns discloses insufficiencies in that mask design. In particular, the suspended photoresist portion of the mask must be narrowed to such a degree relative to its length that it sags and contacts the substrate directly beneath it. An additional problem occurs when the void portion beneath the suspended portion is so large that subsequent depositions cover portions of the substrate beneath the bridge (“overspray”), leading to inconsistent definition of the trackwidth. Referring to FIG. 1a there is shown, schematically, an overhead view of a suspension-bridge mask of the type taught by Han et al., formed in a “dog-bone” shape, wherein a narrow central portion (5) of the upper photoresist portion of the mask are supported by its distal ends (10), which are flared outward and rest on lower, undercut pedestal regions (20), which cannot be seen from above and are shown in broken line outline. FIG. 1b shows a cross-sectional transverse view of the same mask (taken through the center line (7) of FIG. 1a), shown above a substrate (50) indicating that the length and width of the central portion (5) are in a proper relationship relative it its thickness so that it remains properly suspended (9) above the substrate. Referring next to FIG. 2a, there is shown a side view of a mask similar to that in FIGS. 1a,b, except that the suspended central region (5) is narrower than that in FIGS. 1a,b, causing it to sag between its supports (20) and contact the substrate (50). Referring next to FIG. 2b, there is shown a cross-sectional view of a mask similar to that in FIG. 2a taken transversely through the narrow portion. In this mask, the central suspended portion (5) does not sag, but rather leaves to great a space between itself and the substrate (50). The deposition of a layer (30), such as a dielectric layer, a conducting lead layer or a magnetic biasing layer, produces undesirable regions of deposition (40), called overspray, beneath the suspended region. These undesirable regions effectively reduce the trackwidth region in an uncontrollable manner. In order to retain the advantageous properties of a suspension bridge type mask as are set forth in detail in Han et al., yet to eliminate problems such as sagging or excessive space beneath the suspended portion as the mask is formed for use in increasingly narrow patterning processes, the present invention teaches a novel, modified, suspension bridge type lift-off mask in which the central suspended portion is rendered incompletely suspended by the formation of a thin ridge that runs between the distally located bridge supports formed from the underlayer, which ridge maintains the bridge at a fixed height relative to the substrate. The formation of such a ridge requires that the underlayer be very carefully etched so that the ridge offers mechanical stability and is reproducible, yet still eliminates the problems of fencing and mask collapse. Prior art methods of dissolving the lower PMGI layer (eg. use of organic solvents or anisotropic plasma etches) to form the suspended bridge are either insufficiently controllable or damaging to the upper layer to be used to form the thin ridge structure. Therefore, the present method introduces a novel ozone oxidation method which effectively retards the dissolution rate of the PMGI in an organic solvent, rendering the rate and degree of undercut controllable with a high degree of precision. The use of ozone in an etching ambient is known in the prior art, where it has been applied to the etching of certain layers having an alloyed or elemental metal composition. Morgan et al. (US Patent Application Publication No.: U.S. 2003/0170961 A1) teaches the etching of a portion (millimeters in dimension) of a layer formed of metals such as platinum, ruthenium, rhodium, palladium, iridium and their mixtures in an ambient comprising a halogenide, ozone and H2O. The method taught therein, however, does not contemplate the controlled etching of a PMGI layer to form an etch mask which is dimensionally less than a micron in width. SUMMARY OF THE INVENTION A first object of this invention is to provide a lithographic method for patterning a giant magnetoresistive (GMR) read element in any of various configurations including current-in-plane (CIP), current-perpendicular-to-plane (CPP) and tunneling magnetoresistive (TMR), so that it has a trackwidth that is less than approximately 0.1 microns. A second object of this invention is to provide such a method for forming dielectric layers, conductive lead layers and magnetic bias layers laterally disposed to the trackwidth region, wherein the lead and bias layers so formed do not exhibit excessive and unwanted material buildup (overspray) which can lead to poor definition of the trackwidth region, or fencing, which can lead to poor lift-off of the mask. A third object of this invention is to provide a method for patterning a GMR read element trackwidth and depositing dielectric layers, conductive lead layers or magnetic bias layers thereon, using a bi-layer lift-off mask having a central, substantially suspended upper layer which is maintained at a fixed height over a substrate by a ridge running longitudinally beneath the said suspended upper layer, wherein said ridge is an extension of and runs continuously between two distal lower pedestal regions formed of a lower layer. In accord with the objects of this invention there is provided a bi-layer (upper and lower layer) lift-off mask, the upper layer of the mask (the stencil or image-forming layer) having, in an overhead perspective, a “dog-bone” shape, in which a narrow central region is continuously connected to two flared distal regions. The mask is schematically illustrated in FIG. 3a and will be discussed more fully below in the context of the description of the preferred embodiments. The upper layer of the bi-layer structure is formed of a photoresist material (or a material which can be exposed by appropriate radiation and developed) and the lower layer is formed of a PMGI polymer. The lower layer, which has substantially the same dog-bone shape as the upper layer and is symmetrically placed beneath the upper layer, cannot be seen from overhead, because it is uniformly undercut by being differentially etched relative to the upper region. The lower layer thereby attains a final shape as two distally disposed flared supports connected by a thin ridge running longitudinally between said supports. The thin ridge is substantially beneath the narrow central portion of the upper layer and maintains that portion at a fixed distance from a substrate on which the mask is formed. The flared supports serve as pedestals beneath the flared distal regions of the upper layer. The differential etching of the lower layer is accomplished by a novel method combining the use of selected organic photoresistive materials for the mask layers, an initial dissolution of the lower mask layer by an organic solvent, such as a 1.79% solution of TMAH (tetramethyl ammonium hydroxide), followed by a precisely controlled ozone oxidation process (without the TMAH) at an elevated processing temperature to create the final shape. It is noted that the use of TMAH alone produces an etch rate that is too high for the controlled thinning necessary to produce the ridge. On the other hand, anisotropic plasma etches, such as oxygen plasma etches, damage the upper layer of the mask. Thus, the combination of the initial use of TMAH alone, and the subsequent ozone oxidation produces the required control of the etch process that allows the objects of the invention to be achieved. Referring to FIG. 4, there is shown an experimentally determined graph of the rate at which the underlayer is thinned vs. the processing time allotted to a TMAH dissolution and, in comparison, an ozone-assisted dissolution. It is seen from the steep slope of the TMAH curve that good control of the thinning is nearly impossible to obtain, while the smaller slope of the ozone-assisted dissolution (at three decreasing process temperatures, T1, T2 and T3) allows the controlled thinning required by the invention. It is found experimentally that the dissolution rate of PMGI in a 1.79% solution of TMAH is about 10 nm/sec. Thus, a PMGI layer beneath an upper photoresist layer of thickness less than 100 nm. will be completely dissolved in less than 5 seconds. In the ozone-assisted process (no TMAH), the thickness reduction in the PMGI layer proceeded at lower rates between 0.2 and 0.3 nm./sec. Once the etch is completed, the central, narrow portion of the upper layer's dog-bone shape is then used both as an etching stencil to pattern the substrate (which is typically a layered GMR configuration) in accord with the upper layer's image, and as a deposition mask to allow a deposition of laterally disposed dielectric layers (or conducting, or magnetic layers). BRIEF DESCRIPTION OF THE DRAWINGS The objects, features and advantages of the present invention are understood within the context of the Description of the Preferred Embodiments, as set forth below. The Description of the Preferred Embodiments is understood within the context of the accompanying figure, wherein: FIGS. 1a and b are schematic overhead and transverse cross-sectional representations of a suspension-bridge type bi-layer lift-off mask of the prior art. FIGS. 2a and b are schematic side view and transverse cross-sectional views of a suspension-bridge type bi-layer lift-off mask of the prior art showing sagging and overspray. FIGS. 3a and b are schematic overhead and transverse cross-sectional views of the present invention. FIG. 4 shows a graphical indication of the etch control provided by the use of ozone-assisted oxidation compared to TMAH dissolution alone. FIG. 5 shows a substrate overlaid with a layer of PMGI and a layer of photoresist being exposed to radiation. FIGS. 6a and b show overhead and transverse cross-sectional views of an initial patterning of the bi-layer mask. FIGS. 7a and b show final overhead and transverse cross-sectional views of the mask of FIGS. 6a and b. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a bi-layer lift-off mask having, in an overhead view, a dog-bone shape and formed of different upper and lower material layers. Although both the upper and lower layers have similar shapes, the lower layer is substantially undercut relative to the upper layer. The upper layer of the mask has a narrow central portion that flares out to form broader distal portions. The central portion is held at a fixed height above a substrate by a ridge that connects two distally disposed pedestal regions formed from the lower layer. The ridge and pedestal regions are formed entirely of a single piece of the lower material layer by differentially etching the lower material layer relative to the upper material layer in a carefully controlled manner to be fully described below. Referring to FIG. 3a, there is seen in a schematic overhead view the dog-bone shape of the upper (image) layer (60) and, in dashed lines (70) the similar shape of the lower (support) layer. It is understood that this figure illustrates the finished mask, subsequent to the patterning of the upper and lower layers. The narrow central upper portion of the mask, of width W1 and length L1, is shown circled (80) and the thin ridge (90) formed entirely from the lower layer is shown in dashed outline beneath the central portion. The distal flared regions of the upper layer (110) and corresponding supporting flared pedestal regions of the lower layer (100) are also shown. A line drawn transversely across the circled region (80) defines a transverse cross-sectional cut illustrated in FIG. 3b, also showing the substrate (50) and the central region (5) suspended above the substrate by the lower ridge (90). The materials appropriate for forming the upper layer include both positive and negative tone deep-ultraviolet (DUV) resists, E-beam resists and X-ray resists. The lower layer material includes PMGI and its derivatives. In a typical mask formation, the thickness of the upper, photoresist, layer is between approximately 0.1 to 2.0 microns. The thickness of the underlayer is in the range between approximately 0.03 to 0.1 microns. The width, W1, is in the range between approximately 0.04 and 0.3 microns and the length of the bridge, L1, is between approximately 0.5 and 2.0 microns. Although three specific examples will be given below, general parameters for ozone processing include a temperature range between approximately 50° and 150° C., an ozone concentration in the range between approximately 50 and 500 grams per cubic meter, and an ozone flow rate between approximately 5 and 50 liters per minute. Referring again to FIG. 3b, there is shown the mask of FIG. 3a in cross-sectional schematic view. The cross-section of the central portion of the upper layer (5) is shown supported by the ridge of the lower layer (90), which contacts the substrate (50). The presence of the ridge prevents sagging of the central portion (5) and also prevents overspray of subsequent layer depositions (see FIG. 2b). The following three examples will illustrate preferred materials, process parameters, dimensions and methods for forming a bi-layer lift-off mask meeting the objectives of the present invention. EXAMPLE 1 1. Referring to FIG. 5, there is shown a substrate (50), which would typically be a GMR layered configuration of the CIP, CPP or TMR type, but which could be any layer require an ultra-thin patterning, which is to be patterned by a mask directly upon it. On the substrate is formed a layer (20) of PMGI approximately 50 nm. thick. A layer of DUV sensitive photoresist (30), commercially available NEB22A2 in this example, but not limited to this particular material, approximately 200 nm. thick is formed on the PMGI. The dual layer is patterned by KrF DUV photolithography (incident radiation being shown as arrows). It is understood that DUV radiation may be supplied by a variety of radiation sources including coherent radiation sources such as KrF and ArF lasers. Alternatively, with a proper choice of photoresistive material, E-beam and X-ray sources may also be used for exposure. Referring to FIG. 6b, there is shown, schematically, the exposed formation in an overhead view while FIG. 6a shows, schematically, a transverse cross-sectional view of the formation through the narrow central portion. Unexposed portions of the layers have been removed by TMAH development leaving the upper photoresist portion (30) and the lower, undercut, PMGI layer beneath it (20), shown in dashed outline. The formation has been post-baked and developed in a solution of 1.79% TMAH, but concentrations up to 2.38% may be used. The exposed narrow central portion of the photoresist layer (30) is thereby reduced to an initial width of approximately 200 nm. and the corresponding central portion of the PMGI (20) is reduced in width to approximately 100 nm. 2. Referring next to FIGS. 7a and b, there is shown, schematically, the final shape of the patterned dual resist/PMGI bi-layer of FIGS. 6a and b subsequent to having been placed in an ozone processing chamber at 80° C. for approximately 5.5 min (but process times between 1 and 30 minutes may be required). The ozone concentration is maintained at 100 grams/m3 at a flow rate of 10 liters/min. Arrows (70) schematically indicate the ozone flow. The TMAH developing solution is not present during this final controlled undercut so that the ozone, acting alone, can reduce the dimensions of the upper and lower layers to the required narrow widths in a controlled manner. 3. Referring again to FIGS. 7a and b, there is shown in an overhead view the final width of the upper photoresist layer (30), which is reduced to 100 nm., while the final width of the PMGI layer beneath (20) it is reduced to 32 nm. The following two examples can be read instructively with reference to the same FIGS. 5-7. Although the examples are described more briefly than the example above, the rationale for all process steps remains the same. EXAMPLE 2 1. A layer of PMGI approximately 500 angstroms thick is deposited on a substrate. A layer of photoresist, NEB22A2, approximately 2000 angstroms thick is formed on the PMGI. The dual layer is patterned by KrF photolithography, then developed in 1.79% TMAH so that the photoresist layer is reduced to an initial width of approximately 200 nm. and the corresponding PMGI width is approximately 120 nm. 2. The patterned dual resist/PMGI bi-layer is then placed in an ozone chamber at 80° C. for approximately 7.5 min. The ozone concentration is maintained at 100 grams/m3 at a flow rate of 10 liters/min. 3. The final width of the upper photoresist layer is reduced to 65 nm., while the final width of the PMGI layer beneath it is reduced to 17 nm. EXAMPLE 3 1. A layer of PMGI approximately 500 angstroms thick is deposited on a substrate. A layer of photoresist, NEB22A2, approximately 2000 angstroms thick is formed on the PMGI. The dual layer is patterned by KrF photolithography, then developed in 1.79% TMAH so that the photoresist layer is reduced to an initial width of approximately 293 nm. and the corresponding PMGI width is approximately 60 nm. 2. The patterned dual resist/PMGI bi-layer is placed in an ozone chamber at 80° C. for approximately 1, 4 and 8 min. The ozone concentration is maintained at 100 grams/m3 at a flow rate of 10 liters/min. 3. The final width of the PMGI layer beneath it is reduced to 40, 30 and 15 nm. respectively. As is understood by a person skilled in the art, the preferred embodiment of the present invention is illustrative of the present invention rather than limiting of the present invention. Revisions and modifications may be made to methods, materials, structures and dimensions employed in fabricating a bi-layer lift-off mask for patterning a GMR read head of CIP, CPP or TMR configuration having a trackwidth below 0.1 microns, while still providing a method for fabricating a a bi-layer lift-off mask for patterning a GMR read head of CIP, CPP or TMR configuration having a trackwidth below 0.1 microns in accord with the spirit and scope of the present invention as defined by the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention This invention relates generally to the fabrication of a giant magnetoresistive (GMR) magnetic field sensor in the current-perpendicular-to-plane (CPP) configuration, more specifically to the use of a novel bi-layer lift-off mask to pattern such a sensor having an ultra-narrow track width. 2. Description of the Related Art Magnetic read sensors that utilize the giant magnetoresistive (GMR) effect for their operation must be patterned to produce a required trackwidth. Such patterning is conventionally done using a single photolithographic lift-off mask as both an etching stencil and a deposition mask. The shape of the stencil portion of such a mask permits the necessary trimming of the deposited layers to the required trackwidth and then the mask is used to allow deposition of additional layers (eg. conduction lead layers, biasing layers and/or insulation layers) within the removed regions. If the trackwidth of the read element is to be held below about 0.1 microns, then the prior art methods of forming the prior art masks have notable shortcomings. Han et al. (U.S. Pat. No. 6,493,926), assigned to the same assignee as the present invention and which is fully incorporated herein by reference, discusses several problems associated with prior art lift-off masks in which an upper (stencil) layer of photoresist is formed over a lower, undercut, pedestal, layer. In such mask designs the width of the pedestal layer becomes a critical factor in the proper performance of the mask during the deposition stage. If the pedestal is undercut too much, the upper portion of the mask can collapse prematurely under the weight of deposition residue making a clean lift-off of the mask impossible. On the other hand, if the pedestal is insufficiently undercut, subsequent depositions can build up against the pedestal, called “fencing,” leading to excessive thicknesses of the deposited material and short-circuiting of conductive layers. To overcome the difficulties of forming properly and consistently undercut pedestals and for use in forming trackwidths of approximately 0.5 microns, Han et al. teach the formation of a bi-layer suspension-bridge mask formation, in which there is no pedestal directly beneath the upper portion of the mask, but wherein the upper portion is supported on two pedestals that are laterally disposed beneath two distal ends of the mask. The complete elimination of any support directly beneath the mask thereby avoids the problems associated with insufficient or overly-sufficient pedestal undercut. The formation taught by Han et al. requires that the portion of the mask that would ordinarily be beneath the upper portion be completely removed, so that the upper portion is suspended above the device to be patterned and does not contact it. This object is achieved by forming the pedestal portion of the mask of a layer of PMGI, while forming the upper portion of the mask of a layer of photoresist material. Application of a proper developing solution thereupon dissolves the lower PMGI portion preferentially relative to the photoresist upper portion, removing the PMGI except beneath the end portions where it remains to serve as a support. Fontana J R., et al. (US Patent Application Publication No. U.S. 2002/0167764 A1) also teach the formation of a suspension bridge type bi-layer lift-off mask in which a layer of PMGI (polydimethylglutarimide) polymer is first spun onto a substrate and then a layer of PMMA is spun over the PMGI layer. An e-beam is then used to form a mask pattern in the upper layer by developing the upper layer and the PMGI layer is dissolved to form the undercut region. The method taught by Han et al. was applied to patterning trackwidths on the order of 0.5 microns. Attempts to apply the method of Han et al. to produce trackwidths below 0.1 microns discloses insufficiencies in that mask design. In particular, the suspended photoresist portion of the mask must be narrowed to such a degree relative to its length that it sags and contacts the substrate directly beneath it. An additional problem occurs when the void portion beneath the suspended portion is so large that subsequent depositions cover portions of the substrate beneath the bridge (“overspray”), leading to inconsistent definition of the trackwidth. Referring to FIG. 1 a there is shown, schematically, an overhead view of a suspension-bridge mask of the type taught by Han et al., formed in a “dog-bone” shape, wherein a narrow central portion ( 5 ) of the upper photoresist portion of the mask are supported by its distal ends ( 10 ), which are flared outward and rest on lower, undercut pedestal regions ( 20 ), which cannot be seen from above and are shown in broken line outline. FIG. 1 b shows a cross-sectional transverse view of the same mask (taken through the center line ( 7 ) of FIG. 1 a ), shown above a substrate ( 50 ) indicating that the length and width of the central portion ( 5 ) are in a proper relationship relative it its thickness so that it remains properly suspended ( 9 ) above the substrate. Referring next to FIG. 2 a , there is shown a side view of a mask similar to that in FIGS. 1 a,b , except that the suspended central region ( 5 ) is narrower than that in FIGS. 1 a,b , causing it to sag between its supports ( 20 ) and contact the substrate ( 50 ). Referring next to FIG. 2 b , there is shown a cross-sectional view of a mask similar to that in FIG. 2 a taken transversely through the narrow portion. In this mask, the central suspended portion ( 5 ) does not sag, but rather leaves to great a space between itself and the substrate ( 50 ). The deposition of a layer ( 30 ), such as a dielectric layer, a conducting lead layer or a magnetic biasing layer, produces undesirable regions of deposition ( 40 ), called overspray, beneath the suspended region. These undesirable regions effectively reduce the trackwidth region in an uncontrollable manner. In order to retain the advantageous properties of a suspension bridge type mask as are set forth in detail in Han et al., yet to eliminate problems such as sagging or excessive space beneath the suspended portion as the mask is formed for use in increasingly narrow patterning processes, the present invention teaches a novel, modified, suspension bridge type lift-off mask in which the central suspended portion is rendered incompletely suspended by the formation of a thin ridge that runs between the distally located bridge supports formed from the underlayer, which ridge maintains the bridge at a fixed height relative to the substrate. The formation of such a ridge requires that the underlayer be very carefully etched so that the ridge offers mechanical stability and is reproducible, yet still eliminates the problems of fencing and mask collapse. Prior art methods of dissolving the lower PMGI layer (eg. use of organic solvents or anisotropic plasma etches) to form the suspended bridge are either insufficiently controllable or damaging to the upper layer to be used to form the thin ridge structure. Therefore, the present method introduces a novel ozone oxidation method which effectively retards the dissolution rate of the PMGI in an organic solvent, rendering the rate and degree of undercut controllable with a high degree of precision. The use of ozone in an etching ambient is known in the prior art, where it has been applied to the etching of certain layers having an alloyed or elemental metal composition. Morgan et al. (US Patent Application Publication No.: U.S. 2003/0170961 A1) teaches the etching of a portion (millimeters in dimension) of a layer formed of metals such as platinum, ruthenium, rhodium, palladium, iridium and their mixtures in an ambient comprising a halogenide, ozone and H 2 O. The method taught therein, however, does not contemplate the controlled etching of a PMGI layer to form an etch mask which is dimensionally less than a micron in width. | <SOH> SUMMARY OF THE INVENTION <EOH>A first object of this invention is to provide a lithographic method for patterning a giant magnetoresistive (GMR) read element in any of various configurations including current-in-plane (CIP), current-perpendicular-to-plane (CPP) and tunneling magnetoresistive (TMR), so that it has a trackwidth that is less than approximately 0.1 microns. A second object of this invention is to provide such a method for forming dielectric layers, conductive lead layers and magnetic bias layers laterally disposed to the trackwidth region, wherein the lead and bias layers so formed do not exhibit excessive and unwanted material buildup (overspray) which can lead to poor definition of the trackwidth region, or fencing, which can lead to poor lift-off of the mask. A third object of this invention is to provide a method for patterning a GMR read element trackwidth and depositing dielectric layers, conductive lead layers or magnetic bias layers thereon, using a bi-layer lift-off mask having a central, substantially suspended upper layer which is maintained at a fixed height over a substrate by a ridge running longitudinally beneath the said suspended upper layer, wherein said ridge is an extension of and runs continuously between two distal lower pedestal regions formed of a lower layer. In accord with the objects of this invention there is provided a bi-layer (upper and lower layer) lift-off mask, the upper layer of the mask (the stencil or image-forming layer) having, in an overhead perspective, a “dog-bone” shape, in which a narrow central region is continuously connected to two flared distal regions. The mask is schematically illustrated in FIG. 3 a and will be discussed more fully below in the context of the description of the preferred embodiments. The upper layer of the bi-layer structure is formed of a photoresist material (or a material which can be exposed by appropriate radiation and developed) and the lower layer is formed of a PMGI polymer. The lower layer, which has substantially the same dog-bone shape as the upper layer and is symmetrically placed beneath the upper layer, cannot be seen from overhead, because it is uniformly undercut by being differentially etched relative to the upper region. The lower layer thereby attains a final shape as two distally disposed flared supports connected by a thin ridge running longitudinally between said supports. The thin ridge is substantially beneath the narrow central portion of the upper layer and maintains that portion at a fixed distance from a substrate on which the mask is formed. The flared supports serve as pedestals beneath the flared distal regions of the upper layer. The differential etching of the lower layer is accomplished by a novel method combining the use of selected organic photoresistive materials for the mask layers, an initial dissolution of the lower mask layer by an organic solvent, such as a 1.79% solution of TMAH (tetramethyl ammonium hydroxide), followed by a precisely controlled ozone oxidation process (without the TMAH) at an elevated processing temperature to create the final shape. It is noted that the use of TMAH alone produces an etch rate that is too high for the controlled thinning necessary to produce the ridge. On the other hand, anisotropic plasma etches, such as oxygen plasma etches, damage the upper layer of the mask. Thus, the combination of the initial use of TMAH alone, and the subsequent ozone oxidation produces the required control of the etch process that allows the objects of the invention to be achieved. Referring to FIG. 4 , there is shown an experimentally determined graph of the rate at which the underlayer is thinned vs. the processing time allotted to a TMAH dissolution and, in comparison, an ozone-assisted dissolution. It is seen from the steep slope of the TMAH curve that good control of the thinning is nearly impossible to obtain, while the smaller slope of the ozone-assisted dissolution (at three decreasing process temperatures, T 1 , T 2 and T 3 ) allows the controlled thinning required by the invention. It is found experimentally that the dissolution rate of PMGI in a 1.79% solution of TMAH is about 10 nm/sec. Thus, a PMGI layer beneath an upper photoresist layer of thickness less than 100 nm. will be completely dissolved in less than 5 seconds. In the ozone-assisted process (no TMAH), the thickness reduction in the PMGI layer proceeded at lower rates between 0.2 and 0.3 nm./sec. Once the etch is completed, the central, narrow portion of the upper layer's dog-bone shape is then used both as an etching stencil to pattern the substrate (which is typically a layered GMR configuration) in accord with the upper layer's image, and as a deposition mask to allow a deposition of laterally disposed dielectric layers (or conducting, or magnetic layers). | 20040420 | 20080527 | 20051020 | 93334.0 | 0 | SULLIVAN, CALEEN O | OZONE-ASSISTED BI-LAYER LIFT-OFF STENCIL FOR NARROW TRACK CPP-GMR HEADS | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,827,979 | ACCEPTED | Electronic system to be applied in variable resistance exercise machine | A control system is provided for an exercise machine. The control system varies the resistance of the exercise machine. The control system varies the resistance based on voice commands, based on commands programmed by the user, and based on how the user performs an exercise. The exercise machine can include a pneumatic system that can produce constant or variable resistance during on exercise, can include cable exercises, can include exercises utilizing a cam, and can include a cam that can be moved between different operative positions. | 1. An exercise system including (a) an upwardly extending neck; (b) a sleeve mounted on said neck and displaceable along said neck between at least two operative positions; (c) a pressurized chamber mounted on said sleeve; (d) a piston mounted on said sleeve and moveable between at least two operative positions in said chamber; (e) at least one cam operatively associated with said piston and pivotally mounted on said sleeve; (f) at least one displaceable arm pivotally attached to said sleeve to displace said cam and said piston when said arm is pivoted. | This invention pertains to an exercise method and apparatus. More particularly, the invention pertains to exercise apparatus including a pneumatic system that includes a piston, a piston chamber, and an accumulator connected to the piston chamber such that the piston chamber and accumulator chamber function in essence as a single pressurized chamber. In still another respect, the invention pertains to a pneumatic exercise system of the type described in which a user displaces a lever connected to the shaft of the pneumatic piston. In yet a further respect, the invention pertains to a lever-pneumatic exercise system of the type described, in which a relatively small accumulator is used to receiver air displaced by the piston when the user displaces the lever during an exercise. In yet another respect, the invention pertains to a lever-pneumatic exercise system of the type described which includes a lever connected to a cam, in which a belt is connected to a cam or to a pulley, and in which the cam has a selected profile. In yet still a further respect, the invention pertains to a lever-pneumatic exercise system of the type described in which one end of a cable or belt is attached to a cam and the other end of a cable or belt is connected to a piston. In yet still another respect, the invention pertains to a lever-pneumatic exercise system of the type described where the lever is connected to the cam with a pin or other fastening device such that the lever and cam are displaced simultaneously. In a further respect, the invention pertains to a lever-pneumatic exercise system of the type described in which the lever can be connected to the cam at different positions on the cam to vary the resistance produced during an exercise, and to enable an individual to begin an exercise with the lever in different positions. In another respect, the invention pertains to a lever-pneumatic exercise system of the type described in which the cam can profiled to vary the resistance produced during an exercise. In still another respect, the invention pertains to a lever pneumatic exercise system of the type described in which a belt interconnects the cam and a piston shaft and extends over a pulley that functions to align one end of the belt in parallel relationship with the piston shaft. In still a further respect, the invention pertains to a lever-pneumatic exercise system of the type described in which the lever is moved up or down to displace the cam and the piston. In yet another respect, the invention pertains to a lever-pneumatic exercise system of the type described in which the lever can be utilized in upward pressing movements (for example, in a squat exercise), for downward pressing movement (for example, in a tricep exercise), and for pulling movements (for example in a lat pull down exercise). In yet a further respect, the invention pertains to a lever-pneumatic exercise system of the type described in which a sensor is used to continuously measure and monitor the pressure in the pneumatic system. In yet still another respect, the invention pertains to a lever-pneumatic exercise system of the type described in which a sensor is used to continuously determine and monitor the position of the piston. In yet still a further respect, the invention pertains to a lever-pneumatic exercise system of the type described in which the sensor used to monitor the position of the piston is a linear motion sensor or a rotary motion sensor. In another respect, the invention pertains to a lever-pneumatic exercise system of the type described in which the position of the piston and the pressure in the system can be utilized to calculate the volume in the piston chamber that is occupied by pressurized gas. In a further respect, the invention pertains to a lever-pneumatic exercise system of the type described including a storage tank for compressed air to be used by the system, which system can comprise a self-contained exercise machine. In another respect, the invention pertains to a lever-pneumatic exercise system of the type described in which the storage tank also serves auxiliary functions such as structural support or furthering the aesthetic appearance of the machine. In still another respect, the invention pertains to a lever-pneumatic exercise system of the type described including a first pressure control valve which is positioned intermediate the storage tank and accumulator-piston system and which can be opened to permit pressurized gas to flow from the tank to the accumulator-piston system to increase the pressure in the accumulator and piston. In still a further respect, the invention pertains to a lever-pneumatic exercise system of the type described including a second pressure control valve which is positioned intermediate the accumulator and piston chamber and which can be opened to permit pressurized gas to flow from the accumulator to the piston chamber. In yet another respect, the invention pertains to a lever-pneumatic exercise system of the type described including a third pressure control valve which can be opened to release into the atmosphere pressurized air from the pneumatic system. In yet a further respect, the invention pertains to a lever-pneumatic exercise system of the type described in which the pressure control valves are operated by a computer. In still a further respect, the invention pertains to a lever-pneumatic system of the type described in which the resistance encountered by a user during an exercise can be varied during both the negative and positive portions of the exercise. In still another respect, the invention pertains to an exercise apparatus in which the resistance encountered by a user during an exercise can be adjusted or selected by entering data into the apparatus by a keyboard, by inserting a preprogrammed data card into the apparatus to permit the apparatus to produce the resistance set forth in the data card for the exercise routine programmed on the data card, by providing data from a remote source via microwave or radio or other signals received and processed by the exercise apparatus, by using a manually operated joystick to adjust the resistance encountered by the user, by the user's voice commands, by the apparatus automatically adjusting the resistance if the user does not complete the full range of motion dictated by an exercise, and by the apparatus automatically adjusting the resistance if the user halts an exercise in mid-range for greater than a predetermined period of time. In still yet another respect, the invention pertains to an exercise apparatus in which the resistance encountered by a user during an exercise can be adjusted or selected by the user changing how far along a path or range of motion the user moves his body or moves a lever during the exercise. In still yet a further respect, the invention pertains to an exercise apparatus in which the user, in order to cause the apparatus to alter the resistance produced by the apparatus enters data to define either (a) the amount of time that must pass when the user pauses during the exercise, or (b) the position of the piston at which a change of resistance should occur. In another respect, the invention pertains to an exercise apparatus in which the user can program the computer to receive voice commands or other sounds that cause the apparatus to change the resistance produced by the apparatus, to go to another step in a preprogrammed exercise routine, or to turn the apparatus on and off. In a further respect, the invention pertains to an exercise apparatus in which the user's voice commands are received and processed by a microphone or other audio sensor so the user can operate the apparatus without using his hands. In still another respect, the invention pertains to an exercise apparatus including a speaker to generate for a user audible welcomes, goodbyes, warnings, instructions, background music, or other preprogrammed information. In still a further respect, the invention pertains to an exercise apparatus that produces different resistances during the positive portion of an exercise. In still another respect, the invention pertains to an exercise apparatus that produces different resistances during the negative portion of an exercise. In yet a further respect, the invention pertains to an exercise apparatus of the type described than can maintain a constant resistance during an exercise or that can vary the resistance encountered by a user during an exercise. In yet another respect, the invention pertains to an exercise apparatus of the type described in which the position and orientation of a lever and a cam can be altered simultaneously or separated to vary the resistance encountered during an exercise and to vary the exercise performed when a user grasps and displaces the lever. In a further respect, the invention pertains to an exercise apparatus of the type described that monitors the pressure in the swept volume of the piston chamber or in the accumulator, that determines if the pressure properly correlates to the resistance selected for the exercise, and that, if necessary, adjusts the pressure to correspond to the desired pressure. In another respect, the invention pertains to an exercise apparatus of the type described that retains in memory, for a desired resistance or resistances to be encountered by a user during an exercise, the desired swept volume pressure when the piston is a selected positions in the piston chamber. A wide variety of exercise equipment is known in the art. However, most pneumatic exercise apparatus does not enable a user to either encounter a constant resistance during an exercise or to encounter a varying resistance during an exercise does not appear to be available. Further, apparatus does not appear to be available that enables a user to utilize a variety of verbal, manual, and automatic mechanisms to change the resistance encountered during an exercise. Instead, the user is limited to halting execution of an exercise, to stepping out of the position required to execute the exercise, or to pushing buttons to vary the resistance produced by the apparatus. Accordingly, it would be highly desirable to provide an improved pneumatic exercise apparatus that facilitates adjustment at any point during an exercise of the resistance encountered by the user. Therefore, it is a principal object of the invention to provide an improved exercise apparatus. Another object of the invention is to provide an improved exercise apparatus that utilizes variable, pneumatically controlled resistance. A further object of the invention is to provide an improved pneumatic exercise apparatus that provides verbal, manual, automatic, mechanical, and data entry mechanisms for controlling operation of the apparatus. Still another object of the invention is to provide improved pneumatic exercise apparatus that can provide constant or variable resistance during an exercise. Still a further object of the invention is to provide an improved pneumatic exercise apparatus that can be reconfigured both to allow different exercise to be performed and to adjust the resistance provided during the performance of an exercise with the apparatus. Yet another object of the invention is to provide improved pneumatic exercise apparatus that can provide differing resistances during the negative and positive portions of the exercise. Yet still a further object of the invention is to provide different weights (i.e., resistances) during the positive part of an exercise. Yet still another object of the invention is to provide different weights (i.e., resistances) during the negative part of an exercise. These and other, further and more specific objects and advantages of the invention will be apparent from the following detailed description of the invention, taken in conjunction with the drawings, in which: FIG. 1 is a schematic diagram illustrating one embodiment of the exercise apparatus of the invention; FIG. 2 is a schematic diagram illustrating components contained in the position feedback conversion unit included in the exercise apparatus of FIG. 1; FIG. 3a is a schematic diagram illustrating components contained in the pressure feedback conversion unit included in the exercise apparatus of FIG. 1; FIG. 3b is a schematic diagram further illustrating components contained in the actuator interface unit included in the apparatus of FIG. 1; FIG. 4a is a schematic diagram illustrating components in the visual/tactile interface unit included in the exercise apparatus of FIG. 1; FIG. 4b is a schematic diagram illustrating components in the verbal interface unit in the exercise apparatus of FIG. 1; FIG. 5a is a schematic diagram illustrating components in the communication unit in the exercise apparatus of FIG. 1; FIG. 5b is a schematic diagram illustrating components in the detachable storage interface unit in the exercise apparatus of FIG. 1; FIG. 6 is a schematic diagram illustrating components in the control unit in the exercise apparatus of FIG. 1; FIG. 7a is a graph representing the relation between the pressure in the piston chamber and the position of the piston in the piston chamber; FIG. 7b is a graph representing the relation between minimum and maximum pressures achieved during operation of the exercise apparatus of the invention; FIG. 7c is a graph representing the relation between the user range, the pressure in the piston chamber, and the position of the piston in the piston chamber; FIGS. 8a to 8g are flow diagrams illustrating a program utilized in operating one embodiment of the invention; FIG. 9 is a perspective view illustrating an exercise machine constructed in accordance with the invention and with exercise bars position for a user to begin a bench press; FIG. 10 is a perspective view of the exercise machine of FIG. 9 illustrating the position of the exercise bars after the user has displaced the bars upwardly the greatest possible distance; FIG. 11 is a side elevation view of the exercise machine of FIG. 9 illustrating the position of the carriage, cams, and exercise bars when the exercise machine is used to perform a bench press; FIG. 12 is a side elevation view of the exercise machine of FIG. 9 illustrating the position of the carriage, cams, and yolk when cables on the exercise machine are used to perform exercises; FIG. 13 is perspective view of the exercise machine of FIG. 9 configured to perform cable exercises and illustrating use of the machine to perform a leg flex exercise; FIG. 13A is an enlarged perspective view of a portion of the machine of FIG. 13 illustrating cable pulleys; FIG. 13B is an enlarged perspective view of the carriage of the exercise machine of FIG. 13 illustrating the carriage positioned at the bottom of the hollow neck of the machine; FIG. 14 is a side elevation view of the exercise machine of FIG. 13 illustrating the path of cables used during a leg flex exercise and illustrating movement of the carriage during the exercise; FIG. 15 is a side elevation view of the upper portion of the exercise machine of FIG. 13 illustrating the position of the carriage and of cables at the beginning of a leg flex exercise and at the beginning of exercise using other cables with distal ends located adjacent the bench of the exercise machine; FIG. 16 is a perspective view illustrating the position of the carriage and of cables at the beginning of a leg flexion exercise; FIG. 16A is a perspective view further illustrating the position of the carriage at the beginning of a leg flexion exercise; FIG. 17 is a perspective view illustrating the position of the carriage and of cables at the greatest travel or extension of the cables in the leg flexion exercise; FIG. 17A is a perspective view illustrating the position of the carriage at the greatest travel or extension of the cables in the leg flexion exercise; FIG. 18 is a perspective view illustrating the position of the carriage and of the cables at the beginning of an exercise using the platform pulley cables; FIG. 18A is a perspective view illustrating the position of the carriage at the beginning of the exercise using the platform pulley cables; FIG. 19 is a perspective view illustrating the position of the carriage and cables at the greatest travel or extension of the cables used in the platform pulley cable exercise; FIG. 19A is a perspective view illustrating the position of the carriage at the greatest travel or extension of the cables in the platform pulley cable exercise; FIG. 20 is a perspective view illustrating the position of the carriage and of the cables at the beginning of an exercise using the mid-range pulley cables; FIG. 20A is a perspective view illustrating the position of the carriage at the beginning of the exercise using the mid-range pulley cables; FIG. 21 is a perspective view illustrating the position of the carriage and cables at the greatest travel or extension of the cables used in the mid-range pulley cable exercise; FIG. 21A is a perspective view illustrating the position of the carriage at the greatest travel or extension of the cables in the mid-range pulley cable exercise; FIG. 22 is a perspective view illustrating the exercise machine of FIG. 9 with the bench removed and with a horizontally oriented bar installed for an exercise that requires use of the vastus lateralis muscles; FIG. 22A is a perspective view illustrating the position of the carriage at the beginning and end of the exercise for the vastus lateralis muscles; FIG. 23 is a side elevation view of the upper portion of the exercise machine of FIG. 22 illustrating the position of the horizontally oriented bar and of the carriage at the beginning of the exercise for the lastus lateralis muscles; FIG. 24 is a side elevation view of the exercise machine of FIG. 22 illustrating the orientation of various components of the machine at the greatest travel or extension of the pulleys; FIG. 25 is a perspective view illustrating the position of the carriage and of the cables at the beginning of the exercise for the lastus lateralis muscles; FIG. 26 is a perspective view illustrating the position of the carriage and cables at the greatest travel or extension of the cables used in the exercise for the lastus lateralis muscles; FIG. 27 is a perspective view illustrating the carriage and associated pulleys and cables; FIG. 28 is a perspective view further illustrating the carriage and associated pulleys and cables; FIG. 29 is a perspective view further illustrating the carriage and associated pulleys and cables with a portion of the carriage removed; FIG. 30 is a perspective view illustrating the mode of operation of the cams in the exercise apparatus; FIG. 31 is a perspective view further illustrating the mode of operation of the cams in the exercise apparatus; and, FIGS. 32 to 40 illustrate an alternate embodiment of the invention. Briefly, in accordance with my invention, we provide an improved exercise system. The system includes a pressurized chamber; a piston moveable between at least two operative positions in said chamber, a first operative position, and a second operative position to increase the pressure in the chamber; a system for, when activated by a control signal, altering the pressure in the chamber without displacing the piston; and, a system responsive to a voice command to generate the control signal to activate the system. In another embodiment of the invention, we provide an exercise system including a pressurized chamber; a piston moveable between at least two operative positions in the chamber, a first operative position, and a second operative position to increase the pressure in the chamber; a displacement member operable to perform a negative portion and a positive portion of an exercise by moving the piston between the first and second operative positions; and, a system for, when activated by a control signal, producing a pressure in the chamber during the negative portion, and producing a pressure in the chamber during the positive portion that is different from the pressure produced in the chamber during the negative portion. In a further embodiment of the invention, we provide an improved exercise system. The system includes a pressurized chamber; a piston moveable between at least two operative positions in the chamber, a first operative position, and a second operative position to increase the pressure in the chamber; a cam connected to the piston to move the piston between the first and second operative positions; and, a displacement member connected to the cam and operable to perform an exercise by moving the cam to move the piston between the first and second operative positions. In still another embodiment of the invention, we provide an improved exercise system. The system includes a pressurized chamber; a piston moveable between at least two operative positions in the chamber, a first operative position, and a second operative position to increase the pressure in the chamber; and, a cam having at least a pair of operative stations from which the cam is connected to the piston to move the piston between the first and second operative positions. In yet another embodiment of the invention, we provide an improved exercise system. The exercise system includes a pressurized chamber; a piston moveable between at least two operative positions in the chamber, a first operative position, and a second operative position to increase the pressure in the chamber; a plurality of cables operatively associated with the piston and displaceable to perform an exercise by moving the piston between the first and second operative positions; and; a carriage operatively associated with the cables and moveable during the displacement of the cables to perform an exercise by moving the piston between the first and second operative positions. In still yet another embodiment of the invention, we provide an improved exercise system including a pressurized chamber; a piston moveable between at least two operative positions in the chamber, a first operative position, and a second operative position to increase the pressure in the chamber; a cam operatively associated with the piston and displaceable to move the piston between the first and second operative positions; at least one cable operatively associated with the cam to displace the cam and move the piston; and, at least one substantially rigid arm connected to the cam to displace the cam and move the piston. In still yet a further embodiment of the invention, we provide an improved exercise system including a pressurized chamber; at least one cable having a first end and a second end and displaceable between at least two operative positions, a first normal stored operative position and a second distended operative position in which the cable is displaced from the first operative position during an exercise; a system for generating resistance and operatively associated with the first end of the cable; and, a housing to enclose the cable and hide substantially the entire length of the cable from view when the cable is in the first normal stored operative position. In another embodiment of the invention, we provide an improved exercise system including a pressurized chamber; a piston moveable between at least two operative positions in the chamber, a first operative position, and a second operative position to increase the pressure in the chamber; a cam connected to the piston to move the piston between the first and second operative positions, the cam including at least two peripheral portions each having a different shape and dimension; and, a displacement member connected to the cam and operable to perform an exercise by moving the cam to move the piston between the first and second operative positions. In a further embodiment of the invention, we provide an improved exercise system. The system includes a pressurized chamber; a piston reciprocating in the chamber; and, a system for monitoring at selected times both the position of the piston in the chamber and the pressure in the chamber. In another embodiment of the invention, we provide an improved exercise system. The exercise system includes a pressurized chamber; a piston moveable between at least two operative positions in the chamber; and, a storage chamber for supplying gas under pressure to the pressurized chamber and for functioning additionally as a structural member of the exercise system. Turning now to the drawings, which depict the presently preferred embodiments of the invention for the purpose of illustrating the practice thereof and not by way of limitation of the scope of the invention, and in which like reference characters refer to corresponding elements throughout the several views, FIGS. 1 to 8 illustrate one embodiment of the invention. The exercise apparatus illustrated in FIGS. 1 to 8 includes a control system generally indicated by reference character 1, pneumatic system generally indicated by reference character 3, and an exercise machine generally indicated by reference character 2. The exercise machine 2 is connected to piston rod 5 by pivot mechanism 4. The volume of the piston chamber 6 in which air is compressed by the piston decreases when the piston travels into the piston chamber. When the volume of the piston chamber decreases air travels or “bleeds” from the piston chamber 6 to the pressure tank 9. This travel of air from the piston chamber 6 to the pressure tank 9 helps to minimize the increase in resistance to the travel of the piston that occurs when the piston is pushed further and further into piston chamber 6. To increase the resistance encountered by a user when the piston is displaced into chamber 6, the control system 1 opens solenoid valve 11 while maintaining valve 10 in the closed position. Control of valve 11 is accomplished using a control signal 13 (S_VALV1). Signal 13 is a low voltage (TTL) logic signal (C_VALV1) that is adapted by actuator interface unit 17. The low voltage logic signal is generated by controller unit 18. The logical state of the low voltage signal is modified by an algorithm resident in microcontroller 49 (FIG. 6). The signal travels to valve 11 through actuator interface unit 17. Unit 17 contains a driver 32 (FIG. 3b). The driver allows the logical state of signal 34 (C_VALV1) to be coupled to a power signal 13 to control solenoid valve 11. C_VALV1 is converted (or shifted) to S_VALV1 to drive the solenoid. When solenoid valve 11 opens, air 14 from a compressor (not show) flows into pressure tank 9 and increases the pressure in tank 9. Increasing the pressure in tank 9 increases the pressure in chamber 6. Increasing the pressure in chamber 6 increases the resistance that acts on and opposes movement of the piston further into chamber 6. As the piston moves further into chamber 6, the volume of the space in chamber 6 that holds pressurized air decreases. Valve 11 is kept open until the control algorithm used by microcontroller 49 determines that the set point (i.e., a desired pressure level in tank 9) is reached. The control algorithm uses the pressure of air in tank 9 and the position of the piston in chamber 6 to determine the desired pressure level in tank 9. Microcontroller 49 changes the state of signal 13 that causes valve 11 to close. To decrease the resistance encountered by a user when the piston is displaced into chamber 6, microcontroller 49 generates signal 33 (C_VALV2). The logical value of signal 33 is shifted by driver 31 to generate the signal 12 (S_VALV2) that is transmitted by the actuator interface unit 17 to solenoid valve 10. The driver takes C_VALV2 and produces the S_VALV2 signal. Signal 12 causes valve 10 to open. When valve 10 is open, air is discharged into the atmosphere, reducing the pressure in tank 9. Reducing pressure in tank 9 reduces the pressure of air that is in chamber 6 and is opposing movement of the piston into chamber 6. Intake 8 is connected to a pressure sensor 27 in pressure feedback conversion unit 16. Sensor 27 could, for example, be a SenSym Model ASCX100DN, a Motorola Model MPX5700, or another desired brand. The Sensym model is sold by Honeywell Sensing and Control, Pressure Sensors—Sensym ICT, 1804 McCarthy Blvd., Mipitas, Calif. 95025. The Motorola Model is sold by Motorola, Inc., 2501 San Pedro N.E., Suite 202, Albuquerque, N. Mex. 87110. Sensor 27 generates a signal 28 (S_PRER) that is directly proportional to the pressure in intake 8. Signal 28 is produced by sensor 27 using the difference between the atmospheric pressure and the pressure in intake 8. Consequently, sensor 27 functions like a pressure “gauge” in which atmospheric pressure has, in one sense, no effect on the measurement because the atmospheric pressure is constant and the pressure in intake 8 varies. Signal 28 is level shifted and filtered by circuitry 29 to produce analog output signal 30 (S_PREP). Microprocessor 49 converts signal 30 to a numeric value using an analog to digital converter (ADC). When the pressure in intake 8 equals atmospheric pressure, the ADC produces a numeric atmospheric pressure value identifying this condition. When the pressure in intake 8 equals the greatest pressure used in the pneumatic system 3, the ADC produces another different numeric greatest pressure value. For pressures in intake 8 intermediate atmospheric pressure and the greatest pressure, the ADC produces values intermediate the atmospheric pressure value and the greatest pressure value. One way of determining the position of piston rod 5 is by using a position sensor 23 (FIG. 2) to monitor the rotary movement 7 of the pivot mechanism 4. Sensor 23 functions much like a potentiometer. Position feedback conversion unit 15 converts movement 7 to a digital value. Mechanism 4 presently does not rotate clockwise or counterclockwise through more than 360 degrees. Sensor 23 produces signal 24 (S_POSR). Signal 24 is proportional to the rotation of mechanism 4 and, consequently, to the displacement of rod 5 and the piston on rod 5. Signal 24 is conditioned and filtered by signal conditioning circuits 25. Circuits 25 produce signal 26 (S_POSP). Signal 26 is compatible with the ADC in microcontroller 49. The ADC converts signal 26 to a numeric value for use by microcontroller 49. Other means can be used to determine the position of the piston and piston rod 5. Sensors and encoders are available, for example, that can directly measure the linear displacement of the piston rod 5 or of the piston. For each weight (resistance) selected by a user, a control model calculates the desired pressure in tank 9 for each desired position of piston rod 5. These pressures are stored in memory in microcontroller 49. For example, the the possible pressure values for a weight of 200 pounds selected for a “squat” exercise are set forth below in Table I. During a squat, the user begins in a standing position with a bar extending across his shoulders and upper back. The user bends his knees and moves downwardly to a desired position (the negative part of the exercise), and then straightens his knees and moves back to a standing position (the positive part of the exercise). During the negative and positive parts of the exercise, the bar remains on the user's shoulders and upper back. TABLE I Pressure Values Calculated by Control Model for 200 Pounds of Resistance Position of Piston (% of total possible displacement into piston Pressure in Accumulator chamber) Tank (psi) 100 250 90 215 80 200 70 180 60 170 50 150 40 130 30 120 20 100 10 90 0 80 Note: At the 100% position, the piston is pushed as far as possible into the position chamber 6, producing the smallest volume in the piston chamber 6 to hold pressurized gas. At the 0% position, the piston is pulled as far as possible outwardly in the piston chamber, producing the largest volume in the piston chamber 6 hold pressurized gas intermediate the piston and a portion of the piston chamber. Table II below is also for the squat exercise, but the resistance (weight) selected by the user is 125 pounds. TABLE II Pressure Values Calculated by Control Model for 125 Pounds of Resistance Position of Piston (% of total possible displacement into piston Pressure in Accumulator chamber) Tank (psi) 100 160 90 140 80 120 70 100 60 90 50 80 40 70 30 50 20 40 10 30 0 20 Tables similar to those above in Tables I and II can be incorporated into the memory of microcontroller 49 for a variety of exercises that can be carried out using the exercise apparatus of the invention. Or, such tables can be incorporated in a data or memory card that can be slid into or read by the apparatus of the invention. The exercise apparatus can use the information on the memory card in the same way that a computer uses information on a CD or on a “floppy disk”. The computer can operate a program or part of a program using the file on the CD or floppy disk, or, the computer can transfer or copy the information on the disk into computer memory and then use the program based on the information stored in the memory of the computer. Tables similar to those above in Tables I and II can also entered using a keyboard that permits data entry into the memory of the microcontroller 49. The memory of microcontroller 49 can be preprogrammed with tables and information for performing selected exercises on the exercise apparatus. Data for the microcontroller 49 can be input from external sources. Any desired microcontroller can be utilized in the invention. Many microcontrollers (including a microprocessor+memory) are available in the market. The presently preferred microntroller is a TCN-1/1 from Wilke Technologies GMbH. The address of Wilke Technologies is Wile Technology GmbH, Krefelder Str. 147, 52070 Aachen, Germany. The TCN-1/1 microcontroller allows programming in a native multitasking environment and also provides non-volatile memory, analog to digital converters, input/output signals, and communication ports. The user can interact directly with the microcontroller 49 by using the visual/tactile interface unit 20. Unit 20 is shown in FIG. 4a. The parameters listed in Tables I and II, as well as any other desired parameters, can be input using unit 20. A text menu stored in microcontroller 49 is presented to the user using a display bus 35 (D_BUS) interfaced to a liquid crystal display module 36. Module 36 can, for example, be a Model DCM-16204 from Optrex. The address of Optrex is Optrex America, Inc. HQ, 46723 Five Mile Road, Plymouth, Mich. 48170. Microcontroller 49 acquires user inputs by reading keypad or keyboard 38 through bus 37 (K_BUS). Unit 20 is also used to display information to the user during an exercise and to display information concerning an exercise previously completed by the user. Another means for inputting to microcontroller 49 information concerning an exercise is to utilize the detachable storage interface unit 22. The user uses a separate computer to define on a CD, smart card, or other data storage units the data (for example, data like that shown in Tables I and II above) used by microcontroller 49 during an exercise. For example, unit 22 can comprise a smart card or memory card interface circuitry 44 like the LTC1755 produced by Linear Technology Inc. The address of Linear Technology is Linear Technology Corporation, 720 Sycamore Drive, Milpitas, Calif. 95035. The LTC 1755 is coupled to a standard IS07816 connector 45. When a smart card is inserted in ISO connector 45, microcontroller 49 recognizes the presence of the smart card and reads the exercise information (like, for example, the information set forth above in Tables I and II) and other data contained on the smart card. Communication unit 21 (FIG. 5b) permits the exercise apparatus of the invention to obtain information from a remote source. Any desired communication system can be utilized in unit 21. Presently, however, microcontroller 49 communicates with a remote source using serial communication signals 46 (T_BUS) that are processed by conversion circuitry 47 to comply with a standard physical level protocol. The current protocol used is RS232C, which is a low cost alternative and allows direct communication with the majority of currently existing computers and modems. The serial interface illustrated in FIG. 5b permits communication with remote devices using a proprietary data link protocol or using standard protocols such as Internet TCP/IP. The interface not only allows the exercise apparatus of the invention to acquire exercises from local or remote sources but also permit the transmission to such sources of statistical information related to the performance of the user during an exercise. The capabilities of a protocol are limited by program and data memory in microcontroller 49. Any desired protocol or associated apparatus can be incorporated in the exercise apparatus of the invention. Microcontroller 49 includes an algorithm or program that functions like a sequencer. The sequencer reacts to triggers to alter the weight (i.e., the resistance or pressure produced in the piston chamber 6, which resistance opposes movement of the piston into the piston chamber by generating a force that acts to push the piston out of the piston chamber) generated by the pneumatic system 3. A trigger is data that is received by the microcontroller 49 and that causes the microcontroller to alter the pressure produced in chamber 6 when the piston is at a selected position in the chamber 6. One trigger is a signal in an existing program to alter the pressure during an exercise routine. For example, the existing program may specify that after five repetitions of an exercise, the pressure in chamber 6 is increased (or decreased) for the next five repetitions. Microcontroller 49 must, in order to respond to this trigger, be able to monitor the number of repetitions completed by a user. This is currently accomplished by, as described above, monitoring the number of “rotations” or cycles of pivot mechanism 4. Another trigger is a signal to microcontroller 49 that the user did not complete his full range of motion during the most recent repetition of the exercise. The signal ordinarily would cause microcontroller to decrease the pressure in chamber 6. A further trigger is a signal to microcontroller 49 that the user stopped the exercise for a selected period of time while moving between the upper and lower limits of the exercise. For example, during a squat exercise a user may move between the 20% piston position (the lower limit) and the 80% piston position (the upper limit) noted in Table I above. If the user during the positive portion of the exercise displaces the piston to the 70% and stops for at least three seconds, then when microcontroller 49 receives this data (that the piston has been stationary for three seconds at the 70% position), the microcontroller 49 reduces the weight. Still another trigger is a signal in an existing program in a smart card or other removable data storage device that is installed in the exercise apparatus of the invention. For example, the existing program in the smart card may specify that after five repetitions of an exercise, the pressure in chamber 6 is increased (or decreased) for the next five repetitions. Still a further trigger is a voice command from a user. The user may say “NEXT”. The voice recognition system in the exercise apparatus can recognize this command as an indication to increase (or decrease) the weight used in a particular exercise. Or, the voice recognition system can recognize the command as an indication to move on to the next exercise. Yet a further trigger is a command received by the exercise apparatus from a remote source. Yet another trigger is a change in the rate at which a user completes one repetition or part of a repetition of an exercise. For example, if the negative portion of the exercise is completed twice as fast as normal, this trigger may cause the exercise apparatus to reduce the pressure generated in chamber 6 for each position of the piston as the piston moves inwardly and outwardly in chamber 6. The verbal interface unit 19 comprises a voice recognition module like the VOICE EXTREME model provided by Sensory, Inc. The address of Sensory is Sensory Inc., 1991 Russell Avenue, Santa Clara, Calif. 95054-2035. The VOICE EXTREME model allows a user to issue verbal commands to microcontroller and also permit unit 19 to transmit feedback to the user in the form of previously stored messages or in the form of synthesized messages. The voice recognition module 40 (Fib. 4b) communicates with microcontroller 49 using data bus 39 (B_BUS). Module 40 recognizes user voice command signals generated by microphone 42 and generates feedback messages delivered to the use via speaker 41. If desired, the functions performed by module 40 can be integrated in controller 49, in which case the means to convert to digital data voice signals receive from microphone 42 must be included, as well as the means to convert digital data defining feedback messages into signals for speaker 41. In order to perform the desired changes in resistance (weight) requested by a user, a control algorithm resident in the microcontroller 49 is implemented. As will be shown below, for each desired resistance (weight), the control algorithm uses a control model to calculate the pressure value for each position of the piston so that when the microcontroller 49 is requested by the user to increase or decrease the pressure, the microcontroller can determine at each position of the piston whether the desired pressure has been achieved. The control algorithm is also responsible for opening and closing valves 10 and 11 to produce the desired air pressure in piston chamber 6. The control algorithm further is able preferably to so open and close valves 10 and 11 at the same time the user is moving the piston during an exercise. This enables a user to continue an exercise simultaneously with the control algorithm's adjustment of the air pressure in chamber 6. The control algorithm utilizes a control model that describes the relationship between the pressure in chamber 6 and the position of the piston in chamber 6. This relationship between pressure and the position of the piston will depend on the volume of the chamber 6 and the volume of the pressure tank 9 and can be represented by a simple set of linear equations, by stored tables, or by more sophisticated mathematical models. As used herein, 100% indicates the position of the piston when it has been displaced the maximum distance into chamber 6. When the piston is being displaced into chamber 6, the volume between the piston and proximate end of the chamber is decreasing and the pressure in chamber 6 is increasing. And, 0% indicates the position of the piston when it has been displaced the maximum distance away from the proximate end of the chamber. When the piston is being displaced away from the proximate end of the chamber, the volume between the piston and proximate end of the camber is increasing and the pressure in chamber 6 is decreasing. When the piston is at the 10% position, the piston is located a distance from the 0% position that is equal to 10% of the distance between the 0% and 100% positions. When the piston is at the 20% position, the piston is located a distance from the 0% position that is equal to 20% of the distance between the 0% and 100% positions. And so on. During an exercise, a user can move the piston in chamber 6 between at the greatest extents (i.e., can move the piston from the 100% position to the 0% position) of its travel. The user can also, if desired, move the piston in a range that is intermediate the 100% and 0% positions. For example, during an exercise the user can move the piston from its 15% position to its 85% position. In the following example, it is assumed that the sensors and control algorithm utilized determine when the piston is at its 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% positions. It is further assumed that when the user programs a particular weight, i.e. 100 pounds, into the exercise machine, the control algorithm calculates or has stored in memory the pressure that must exist in chamber 6 for each position of the piston in the chamber. For example, if the user selects a weight of 100 pounds, the control algorithm can calculate that the pressure in chamber 6 when the piston is in the 100% position should be 95 psi, that the pressure in chamber 6 when the piston is in the 90% position should be 90 psi, etc. Similarly, if the user selects a weight of 80 pounds, the control algorithm can calculate that the pressure in chamber 6 when the piston is in the 100% position should be 75 psi, that the pressure in chamber 6 when the piston is in the 90% position should be 70 psi, etc. It is further assumed in the following example that the user is performing a bench press in which the piston is, during multiple repetitions of the exercise, reciprocated in chamber 6 between the 40% and 70% positions of the piston. The user programs the exercise machine to perform a bench press and to initially produce 100 pounds of resistance. He also programs the exercise machine to produce 80 pounds of resistance when he verbally commands the machine by saying “NEXT”. The control algorithm calculates for 100 pounds of resistance the pressure values P set forth in Table III for each position X of the piston. TABLE III Position X Pressure P User Range 0% 45 No 10% 50 No 20% 55 No 30% 60 No 40% 65 Yes 50% 70 Yes 60% 75 Yes 70% 80 Yes 80% 85 No 90% 90 No 100% 95 No Note: Bolded values in table indicate values for range through which user will displace piston. The control algorithm calculates for 80 pounds of resistance the pressure values P set forth in Table IV for each position X of the piston. TABLE IV Position X Pressure P User Range 0% 25 No 10% 30 No 20% 35 No 30% 40 No 40% 45 Yes 50% 50 Yes 60% 55 Yes 70% 60 Yes 80% 65 No 90% 70 No 100% 75 No Note: Bolded values in table indicate values for range through which user will displace piston. Before the user begins the exercise, the piston is at the 0% position and the control algorithm operates the valves to produce a pressure of 45 psi as set forth in Table III above. The user positions himself on the apparatus to begin the bench press and, accordingly, grasps and displaces handles or a bar on the exercise machine to move the piston to the 40% position. When the piston is at the 40% position, the control algorithm receives from a sensor a pressure for the piston chamber 6. The reading indicates that the pressure is 65 psi, as required in Table III. Consequently, the control algorithm does not adjust valves 10 and/or 11. The user continues the bench press and makes ten repetitions. During each repetition, the user displaces the handles or bars to move the piston from the 40% position to the 70% position and back to the 40% position. The user begins the eleventh repetition and, when he has displaced the piston to move it from the 40% position to the 50% postition, says “NEXT” to the exercise machine. The exercise machine immediately begins using the data in Table IV. The control algorithm determines that the pressure in chamber 6 when the piston is in the 50% position is 70 psi. This pressure was acceptable when the control algorithm was referencing Table III. The pressure is not acceptable according to Table IV, which requires a pressure of 50 psi. The control algorithm begins operating valve 10 (i.e., valve V2) to reduce the pressure in chamber 6 to a level acceptable to the values set forth in Table IV. The control algorithm continues, while the user continues the exercise repetition, to take pressure measurements and, when necessary, adjust valve 10 and/or 11. The actions taken be the control algorithm, along with the resulting pressure readings, are set forth below in Table V. TABLE V Sam- Desired Sam- Sampled pled P P ple X (Pres- (Pres- Time (Position) sure) sure) Control Algorithm Action 1 50% 70 50 Maintain V2 open, P must, as defined in TABLE II, be 50 not 70 2 50% 68 50 Maintain V2 open, P must, as defined in TABLE II, be 50 not 68 3 60% 67 55 Maintain V2 open, P must, as defined in TABLE II be 55 not 67 4 60% 66 55 Maintain V2 open, P must, as defined in TABLE II, be 55 not 66 5 70% 65 60 Maintain V2 open, P must, as defined in TABLE II, be 60 not 65 6 70% 62 60 Maintain V2 open, P must, as defined in TABLE II, be 60 not 62 7 60% 58 55 Maintain V2 open, P must, as defined in TABLE II, be 55 not 58 8 60% 55 55 Close V2, P level is equal to desired value of 55 as defined in TABLE II As shown in Table V, when a sample pressure was taken at sample time 8 at piston positino 60%, the sampled pressure of 55 psi equaled the desired pressure of 55 psi. As a result, the control algorithm closed valve V2 because there was no need to continue reducing the pressure in chamber 6 to reach the desired pressure set forth in TABLE IV. In the event the sampled pressure P is less than the desired pressure, the process set forth in TABLE V is still followed, but valve 11 (V1) is opened instead of valve 10 (V2) to increase the pressure in chamber 6. As noted above, the control model used by the control algorithm describes the relationship between the pressure in chamber 6 and the position of the piston in chamber 6. This relationship between pressure and the position of the piston will depend on the volume of the chamber 6 and the volume of the pressure tank 9 and can be represented by a simple set of linear equations, by stored tables, or by more sophisticated mathematical models. The control model is used to calculate the pressure data set forth in TABLES III and IV above. A control model is described below that is based on a simple set of linear equations. This linear equation model shows good results when the volume of the pressure tank 9 is much greater than the volume of piston chamber 6. This model is used to simplify the explanation of the functioning of the exercise apparatus and is not used to limit the scope of the invention. Other mathematical equations can be utilized to calculate pressure data when the volume of the accumulator is equal to or less than the volume of the piston chamber 6. The following mathematic control model exemplifies one process that can be utilized by microcontroller 49 to control the resistance or pressure generated in chamber 6 for each position of the piston in chamber 6. The graph depicted in FIG. 7a illustrates the relationship between the pressure in chamber 6 and the position of the piston in the chamber. When the piston is at the 100% position, the piston is displaced into the chamber 6 as far as the piston will go, i.e. the volume of the portion of the chamber 6 that extends between the piston and the inner end of chamber 6 has its smallest value. When the piston is at the 0% position, the piston is displaced outwardly in the chamber 6 as far as the piston will go without completely exiting the chamber, i.e., the volume of the portion of chamber 6 that extends between the piston and the inner end of chamber 6 has its greatest value. The following mathematical expression describes the graph of FIG. 7a: P(x)=Pmin+xy [Eq. 1] y=(Pmax−Pmin)/100 [Eq. 2] P(x) is the pressure in chamber 6 as a function of the position x of the piston (or piston rod 5). The greatest pressure occurs when the piston is in the 100% position. The least pressure occurs when the piston is in the 0% position. For a value of x=50% (i.e., the piston is displaced half way into chamber 6), P(x) is equal to half the pressure value between Pmax and Pmin. The value of Pmax can be calculated from the value of Pmin using an offset value, B, and a proportionality constant K. This relationship between Pmax and Pmin is not linear, but can be linearized with good results. This relationship is illustrated in FIG. 7b and can be represented by the formula: Pmax = B + ( K × Pmin ) = B + ( KPmin ) [ Eq . 3 ] As is depicted in FIG. 7c, during an exercise the range of movement by the user of the piston in chamber 6 need not be from the 0% position to the 100%, but can be between an “upper” and “lower” limit that fall intermediate the 0% and 100% positions. In FIG. 7c, the user range of movement of the piston is depicted as being approximately between the 25% (Dumin) and 65% (Dumax) positions of the piston in chamber 6. Consequently, in FIG. 7c, Pmin occurs at the Dumin position of the piston and Pmax occurs at the Dumax position of the piston in chamber 6. When the user selects an exercise, the user also selects a desired weight for the exercise. The microcontroller correlates the selected weight to be equivalent to a particular pressure at Pmin (or Pmax, if desired). Equations 1 and 3 above can be combined to provide the following expression for determining Pmin: Pmin=m/n [Eq. 4] m=100P(x)−B(x) [Eq. 5] n=100+x(K−1) [Eq. 6] Equation 4 can be substituted in Equation 3 to give: Pmax=B+Km/n [Eq. 7] Equations 4 and 7 can be utilized to calculate Pmax and Pmin at the 100% and 0% positions of the piston, respectively. Once the Pmax and Pmin are calculated, the pressure P(x) for each position x of the piston can be calculated, including the pressure P(x) for positions of the piston in the user range. For example, if the user range is between 40% and 70%, and the resistance (weight) selected by the user is 100 pounds, then TABLE III above illustrates the values P(x) could have for each position x in Equation 1. If the user elects to alter the resistance (weight)—and therefore Pmin and Pmax—during an exercise, microcontroller can readily recalculate the new P(x) value for each position of the piston from 0% to 100%, including the positions of the piston in the user range. Precise control of a pneumatic system is a difficult task due to transient variation in pressure that occur during the manipulation of the valves and due to changes in temperature that occur as gases expand and are compressed. When the pressure in tank 9 is at a selected level and valve 10 opens, the pressure in tank 9 is reduced and the temperature in tank 9 drops. The decrease in temperature contributes to the pressure reduction in tank 9 until the temperature of air or other gases in tank 9 stabilizes and equals that of the ambient air. Similarly, if air from compressor 14 is directed via valve 11 into tank 9, the temperature of the air in tank 9 increases. The temperature increase contributes to the increase in pressure in the tank until, again, the temperature of air in the tank 9 stabilizes and equals the ambient air temperature. Similar effects occur when the movement of the piston in chamber 6 causes air to expand and compress. The foregoing pressure variation caused by variations in gas temperature and believed to have a negligible effect on the operation of the exercise apparatus of the invention and can be, if desired, compensated for at least in part by using correction factors when the microprocessor 49 calculates the values for Pmin, Pmax, and P(x). As is well known in the art, such correction factors can be derived from a model based on current and desired pressures Pmin, Pmax, P(x), or, by a simple table of predefined values. One of the goals of the invention is to be able to replicate equivalent weight changes over time such that when a user repeats an exercise and increases or decreases the “weight” (and therefore pressure P(x)) by the same amounts that the user used the first time he completed the exercise, the weight increases feel the same to the user. The foregoing simplified mathematical model is believed to accomplish this goal and is easily implemented in code for a microcontroller 49. Microcontroller 49 is, as described above, responsible for carrying out P(x) calculations, for performing user interface duties, for communication duties, and for storage and retrieval duties in connection with interface unit 22 and other data sources. The program used by microcontroller 49 is presently coded using a multitasking approach, but a linear coding approach can be implemented if desired. The currently preferred program is described below in more detail with reference to FIGS. 8a to 8g, and not by way of limitation of the scope of the invention. Microcontroller Program The user elects a squat as the exercise and identifies the exercise to the exercise apparatus by entering an appropriate code via keypad 38. The user also indicates that the beginning “weight” will be 200 pounds, followed by one hundred and twenty-five pounds, and then one hundred pounds. The user enters this information with keypad 38 by entering an appropriate code, followed by the weights designations two hundred, one hundred and twenty-five, and one hundred pounds. The control algorithm of the microprocessor uses the control model to calculate for each weight (i.e., for two hundred pounds, for one hundred and twenty-five pounds, and one hundred pounds) the pressure values set forth in TABLES I, II, III, respectively. The user also enters in keypad 38 a code that informs microprocessor 49 that increases in weight will be accomplished by verbal command. The user will say “NEXT” or “MORE” (the apparatus recognizes each command), to increase the weight. The exercise apparatus also recognizes the command “LESS” and will decrease the weight to the previous level on receiving the “LESS” command. In the event the exercise apparatus receives the “LESS” command when the apparatus is only applying a pressure equivalent to the beginning weight of fifty pounds, the apparatus will automatically control the pressure in tank 9 to produce in chamber 6 a weight equal to twenty pounds for each position of the piston in chamber 6. As indicated in FIG. 8a, when the exercise apparatus is turned on, the control program in microcontroller 49 executes the main task 100 by initializing variable 101, by initializing hardware drivers 102 to leave the drivers in a known state during or in preparation for future task, by displaying the turn-on message 103 on a CRT or LCD display 36 or other display screen, and by producing a voice turn-on message 104 over speaker 41. After message 104 is produced, display task 105 is carried out. During this task the control program receives inputs from keypad 38 and sends text messages and information to display 36. The control program then operates and monitors task sensors 106 (i.e., sensors that indicate the position of the position, that indicate the number of repetitions during an exercise, that indicate the time it takes the user to complete a repetition or portion of an exercise, etc.), and runs task control 107 to take the actions necessary for the user to carry out an exercise. The program cycles 108 through the main task 100 continuously. Each task initiated by the program during the main task 100 executes concurrently in time 109. These tasks include display task 120, sensor task 140, and control task 160. Each task is like an independent program and requires the initialization of local variables. Display task 120 is schematically described in FIG. 8b. Task 120 outputs messages to display 36 through bus 35 and also checks for signals from keypad 38 via bus 37. Task 120 is performed each 0.1 seconds by utilizing a delay routine 122. Each time delay routine 122 expires, the task 120 first checks to see if the variables to be displayed have changed since the last iteration 123. If there is a change in any of the variables or text messages, the new values are displayed 124 in display 36. After the new values are displayed, bus 37 (K_BUS) is read 125 and operations are performed 126 to determine if a valid signal from a key in keypad 38 is present. If there is no input from the user via keypad 38, the task loops back to delay routine 122 and waits for another 0.1 second to pass. If there is a valid signal from keypad 38 due a key being depressed, the decode key routine 127 analyzes the signal. If the signal is a valid signal, it is stored 128 to indicate to other tasks that there is a key(s) to be processed. Since the nature of the multitasking program used in this embodiment of the invention is cooperative, care must be taken in performing task so there is no monopolization of CPU time by any one task. An overview of the sensor task 140 is set forth in FIG. 8c and includes the step 141 of initializing local variables, followed by the step 142 of reading the pressure sensor signal 30 (S_PREP) using the microcontroller 49 analog to digital converter. The data in signal 30 is converted in step 142 to a number between 0 and 1023. This raw number is then adjusted 143 to a value compatible with the numeric ranges used by the control program in the exercise apparatus. The adjusted value is stored in the ACTUAL_P global variable memory. Similar operations are performed 144, 145 for the measurement of the position of the piston in the piston chamber 6. In step 146 a state machine is used to determine the average value of the maximum position (Dumax in FIG. 7c) of the piston during multiple repetitions of an exercise. The state machine uses the S_PSOP variable as the input, determines if the current position of the piston is a maximum, and averages the current position with prior maximum positions of the piston. A similar process 147 is utilized to determine the average value of the minimum position (Dumin in FIG. 7c) of the piston. Step 148 utilizes data produced in steps 146 and 147 to determine if the distance traveled by the piston from Dumin to Dumax is increasing, staying the same, or decreasing. The output signal produced by step 148 is DISTANCE_STATE and indicates whether the distance traveled by the piston is increasing, decreasing, or staying the same. Delay routine 149 puts task 140 on hold for 0.050 seconds before restarting task 140. This delay routine 149 frees CPU time for other tasks. Control task 160 (FIG. 8d) includes the step 161 of initializing local variables, followed by step 162 of sending a “WELCOME” text message to display 36 and step 163 of sending a verbal “WELCOME” message to speaker 41. The control program then, via bus 39, configures the voice recognition module 40 to generate a signal when the user gives a verbal command. This is followed by step 164, in which a “BEGIN” text message is sent to display 36. When the user says “BEGIN” in step 165 and microphone 42 generates a signal to module 40, the exercise loop control variables are initialized in step 166. The user says begin when he is in position to begin the exercise and when the user has grasped and displaced a bar or handle in the exercise machine 2 such that the piston is in the Dumax position (FIG. 7c). In step 166, the variable counter is incremented each time the piston travels from Dumin to Dumax (FIG. 7c) during an exercise. Variable I is the pointer to the weight array Pweight(i). The weight array Pweight(i) stores the sequence of weights to be used during an exercise. In this example, the sequence of weight is, as noted above, two hundred pounds, one hundred and twenty-five pounds, and one hundred pounds. The data in array Pweight(i) is provided by any of the means discussed earlier, e.g., by entering data on the keypad, by using a smart card, etc. Variable X is used to calculate the Pmax and Pmin values required to control valves 10 and 11. In step 166, since the user range (FIG. 7c) is not yet known, the control program assumes that the user is beginning the exercise with the piston in the 100% position with the piston fully displaced into chamber 6. Consequently, in step 166 X=100%. The “weight” the pneumatic system 3 needs to generate when the piston is in the 100% position is considered to be the beginning weight. Of course, if desired, the controller 49 can be programmed such that the 0% piston position is the beginning position in each exercise. In step 167, the Pmax and Pmin values are determined. The program knows that a particular weight in pounds selected by the user requires that a certain pressure be generated when the piston is in the 100% position in chamber 6. This is the Pmax value. The Pmin value can be calculated from the Pmax value. The program also calculates values for selected positions of the piston. For purposes of this example, it is assumed that the user is performing a squat (i.e., knee bend) exercise, that the maximum weight occurs when the piston is in the 100% position, that the maximum weight requires a pressure of 250 psi, and that the program calculates the data in TABLE I, which is reproduced below for convenience. TABLE I Pressure Values Calculated by Control Model for 200 Pounds of Resistance Position of Piston (% of total possible displacement into piston Pressure in Accumulator chamber) Tank (psi) 100 250 90 215 80 200 70 180 60 170 50 150 40 130 30 120 20 100 10 90 0 80 The data in Table I is calulated using Equations 1, 3 and 4. As noted in Table I, when the piston is displaced in chamber 6 from the 100% position toward the 0% position, the pressure in the chamber decreases. Consequently, the resistance produced by pressurized gas in chamber 6 is not constant, but varies with the position of the piston in chamber 6. As would be appreciated by those of skill in the art, the microcontroller can be programmed to alter the pressure in tank 9 during an exercise such that substantially constant pressure is maintained in chamber 6 while the piston moves in chamber 6 during an exercise and the volume of gas in the chamber 6 varies. In step 168, after the user puts the piston in chamber 6 at the Dumax position and says “BEGIN”, the control valves 10 and 11 are manipulated to produce the pressure for that position. In this example, in the Dumax position the piston is in the 70% position. In Table I, at the 70% position a pressure of 180 psi is required. Valves 10 and 11 are manipulated by the control algorithm to produce a pressure of 180 psi. In step 169, if after a selected period of time the piston has not moved from Dumax through a distance equal to at least 10% of the total possible displacement of the piston in chamber 6 then in step 170 a “WAITING” text message is sent to and shown by display 36 and a verbal “WAITING” message is sent to and produced by speaker 41. In step 172, structure pointer has accessed Pweight(i) with variable X equal to 100%, and in step 173 the values in TABLE I have been calculated. In step 174, the valves 10 and 11 are manipulated to control the pressure in chamber 6 such that it corresponds to the values set forth in TABLE I while the piston moves in chamber 6 during the exercise. In step 175, the control program in microcontroller 49 receives input from conversion unit 15 concerning the position of the piston. The program determines when the position of the piston begins to increase, i.e., when the user begins to bend his knees and the piston moves from the Dumax position toward the Dumin position. In step 176, the control program in microcontroller 49 determines when the position of the piston begins to decrease. The position of the piston decreases when the piston reaches Dumin, stops, and begins to move from Dumin toward the Dumax position. When the position of the piston begins to decrease, the Dumin position is identified. The program then knows the Dumax and Dumin positions of the piston. As the user continues the exercise, and completes additional repetitions, the program generates Dumax and Dumin data for each repetition and uses the data to calculate average 146 Dumax and 147 Dumin positions for the piston. In step 177, a text “READY FOR NEXT” message is sent to display 36. this message indicates to the user that the exercise apparatus is ready to adjust the pressure in chamber 6 to correspond to the next weight selected for the exercise. The next weight at Dumax might require, for example, a decreased psi of 100 (TABLE II) instead of the 180 psi set forth in TABLE I. The increase or decrease in weight during an exercise can also, as noted, be automated to occur after the user completes a selected number of repetitions of the exercise, after the user exercises for a selected number of minutes, etc. In step 178, when the position of the piston is decreasing and the user says “NEXT”, the program goes to step 185 in FIG. 8f. In step 178, when the position of the piston is decreasing and the user does not say “NEXT”, the program goes to step 180. In step 180, the program determines if the position of the piston is within 15% of the Dumax position. If the piston is within 15% of the Dumax position, the program goes to step 182 in FIG. 8f. If the piston is not within 15% of the Dumax position, the program loops back to step 178. In step 182 the variable counter is incremented. This functions in effect to count the number of repetitions of an exercise being carried by a user using the exercise apparatus of the invention. The number of repetitions of an exercise is displayed to the user on display 36 via TASK_DISPLAY. In step 183, if the position (i.e., the “distance”) of the piston is increasing, the program returns to step 178. If in step 183 the position of the piston is not increasing, the program goes to step 184. In step 184, if the user said “NEXT”, the program goes to step 185. If the user did not say “NEXT”, the program loops back to step 183. In steps 179, 181, and 184, the program asks the voice recognition module 40 if a verbal “NEXT” command has been received. When a verbal “NEXT” command is received via microphone 42, the program moves to step 185. In step 185 the variable i is increased. This functions to select the next weight designated for the exercise being performed by the user. The value of i is checked in step 186 to insure that the number of weights stored in an array for a particular exercise is not exceeded. If the variable i exceeds the number of weight values stored in the exercise array, the prior value of variable i is utilized, i.e., the weight being used is not changed. After step 185 confirms that variable i can be increased, the program determines the pressure that produces the weight at Dumax and, in steps 187 and 188, calculates the pressure in chamber 6 when the piston is at Dumin and when the piston is at other selected positions of the piston in chamber 6. In step 190, the program manipulates valves 10 and 11 to produce the desired pressure in chamber 6 when the piston is at Dumax, Dumin, and the other selected positions of the piston. As earlier noted, TABLE I is an example of the pressure data calculated for various positions of the piston. When the user says “NEXT” and the program utilizes the next weight to calculate new pressure values for each piston position, the program can elect to immediately implement the new values regardless of the position of the piston, or, the program can implement the new values only when the piston is at Dumax or Dumin. After valves are adjusted in step 190, the program returns to step 178. FIG. 8g illustrates the program 200 utilized to calculate pressures in, for example, step 188. This program utilizes the Equations 1, 3, and 4 set forth above. Once the program identifies the pressure necessary to produce a desired “weight” or resistance when the piston is at the 100% position, Equations 1, 3 and 4 can be utilized to calculate the pressures required in chamber 6 at each selected position of the piston in chamber 6. The pressure necessary to produce a desired “weight” at the 100% position of the piston can be entered into and stored in the memory of microcontroller 49 After the pressure values are calculated for each position of the piston, the values can be adjusted to compensate for short-lived pressure changes that occur when the pressure in tank 9 and chamber 6 is altered. In step 203, the new pressure values calculated by program 200 are provided to microcontroller 49. FIG. 8g also illustrates the routine 220 used to manipulate valves 10 and 11 to inject and remove air from tank 9. This routine requires the input of Pmaxi (at the 100% position of the piston), Pmin (at the 0% position of the piston), the current position of the piston (ACTUAL_X) and the current pressure of tank 9 (ACTUAL_P). The first step 221 of the routine 220 is to determine if the existing pressure ACTUAL_P in tank 9 is greater than the pressure required for the current position ACTUAL_X of the piston in chamber 6. By way of example, TABLE I lists required pressures at selected piston positions. If the existing pressure is greater than the required pressure, then in step 222 valve 10 is opened to reduce the existing pressure to the required pressure. After valve 10 is opened, step 223 determines when the existing pressure equals the required pressure. If the existing pressure is still greater than the required pressure, the program loops back to step 222 and maintains valve 10 in an open position. Once the existing pressure equals the required pressure, step 224 closes valve 10, followed by step 228, return to step 220 or another selected portion of the program. If in step 221, the existing pressure is less than the desired pressure, then the program goes to step 225 and opens valve 11 to inject air into tank 9. Step 226 determines whether the existing pressure equals the required pressure. If the existing pressure equals the required pressure, the program proceeds to step 227 and closes valve 11. If the existing pressure is still less than the desired pressure, the program loops back to step 225 and maintains valve 11 in the open position. Subroutine 220 adjusts the pressure in tank 9 (and in chamber 6) when the piston is moving or is stationary. The Exercise Machine FIGS. 9 to 31 illustrate an exercise machine 300 including a control system and other features constructed in accordance with the invention. Machine 300 includes a bench 301 that can be removed by removing quick release pin 308 and lifting bench 301 away from platform 307. Platform 307 is mounted on cylindrical storage unit 309. Unit 309 receives and stores pressurized air or other gases from a compressor (not shown). The compressor can be remote from the machine or can be incorporated in the machine. Unit 309 is operatively connected to accumulator 310 mounted on the front of orthogonal upright hollow neck 331 (FIG. 10). Piston chamber 334 is mounted on the rear of neck 331. A first valve (not visible) like valve 11 in FIG. 1 is interposed between the storage unit 309 and the accumulator 310. This valve is in a pressure line that interconnects unit 309 and accumulator 310. This valve is opened to permit pressurize air from unit 309 to flow into accumulator 310 to increase the pressure in accumulator 310. A second pressure relief valve (not visible) like valve 10 in FIG. 1 is connected to accumulator 310. The pressure relief valve is opened to decrease the pressure in accumulator 310 and, consequently, to decrease the pressure in piston chamber 334. The first and second pressure relief valves are controlled and are opened and closed by a control microprocessor in control panel 311. Panel 311 is mounted on the front of neck 331. Panel 311 also includes a microphone and audio speaker to permit the microprocessor to produce audible words or signals for a user and to permit a user to issue audible commands of the type earlier described, such as, for example, “BEGIN”, “INCREASE” or “MORE” (prompting the machine to increase the resistance generated by chamber 334), and “DECREASE” or “LESS” (prompting the machine to decrease the resistance generated by chamber 334). A metronome 311A is included in and can be controlled by panel 311 so that an individual can, if desired, perform an exercise to a desired cadence. Metronome 311A can be incorporated in the exercise machine at any desired location or can be situated remote from the exercise machine but within hearing distance. A pair of spaced apart interconnected cams 316, 317 are mounted on neck 313. Cams 316, 317 are each connected to a different end of hollow shaft 461. Shaft 461 is rotatably mounted on cylindrical axle 462 that extends through neck 331. See FIG. 30. Cams 316 and 317 and shaft 461 rotate simultaneously. A detented track 440 is formed on the inside of cam 317. Spring loaded pin 444 follows track 440 when cam 317 rotates. Pin 444 is slidably mounted in hollow sleeve 463. Sleeve 463 is fixedly attached to neck 331. Handle 318 is connected to pin 444. Moving handle 318 in the direction of arrow R (FIG. 30) displaces pin 444 away from cam 317 so that cam 317 (and 316) can be rotated downwardly and rearwardly toward chamber 334 from the position illustrated in FIG. 11 to the position illustrated in FIG. 12, and vice-versa. This ability to rotate cams 316 and 317 between two positions significantly increases the versatility of the exercise machine. A piston (not visible) is positioned inside piston chamber 334 in the same manner that a piston is positioned inside chamber 6 in FIG. 1. A piston shaft or rod 329 is connected to the piston in the same manner that piston shaft 5 is connected to the piston in FIG. 1. Shaft 329 is connected to arm member 328. Member 328 is normal to shaft 329. Belt 323 (FIG. 10) is connected to one end of arm member 328. Belt 323A (FIG. 13) is connected to the other end of arm member 328. One end of belt 323 is connected to member 328, the other end of belt 323 is connected to the nose of cam 317. One end of belt 323A is connected to member 328, the other end of belt 323A is connected to the nose of cam 316. In the drawings, each cam 316, 317 is symmetrical about a longitudinal centerline, e.g., the peripheral edge 317A (FIG. 11) of the upper half of the cam has the same shape and dimension, or “profile”, as the profile 317B of the bottom half of the cam. If desired, the profile of the upper half of the cam can differ from the profile of the lower half of the cam. The peripheral edge of the cam can include any desired number of different profiles. Each belt 323, 323A extends through its own operatively associated pair of rollers 324, 325. Accordingly, rotatably reciprocating cams 316 and 317 about axle 462 functions to reciprocate shaft 329 and to reciprocate piston in chamber 334. For example, in FIG. 11 upwardly displacing arm 312 in the direction of arrow T functions to upwardly displace cam 317 (and 316) and arm 312 to the position indicated by the ghost outlines of arm 312 and cam 317 in FIG. 11. When cam 317 is upwardly displaced, it pulls belt 323 upwardly. Pulling belt 323 upwardly displaces arm member 328 in the direction of arrow B to the position indicated by the ghost outline of member 328 in FIG. 11. Since shaft 329 and the piston in chamber 334 are fixedly connected to member 328, shaft 329 and its associated piston are upwardly displaced in the direction of arrow B simultaneously with member 328. Displacing the piston in chamber 334 in the direction of arrow B functions to reduce the volume of space occupied by air in chamber 334. Reducing the volume of the air space causes the pressure of the air to increase. Increasing the pressure of the air increases the resistance opposing movement of the piston in the direction of arrow B. While the shape and dimension of cams 316 and 317 can vary as desired, in one preferred embodiment of the invention, the cams are shaped such that as the pressure in chamber 334 increases, the strength required to displace arm 312 upwardly in the direction of arrow T remains about the same. In other words, the cam enables the resistance produced to remain substantially constant even though the pressure of air in chamber 334 increases when the piston in chamber 334 moves in the direction of arrow B and reduces the volume in chamber 334 that contains the pressurized gas. As shown in FIG. 10, one leg 337 of U-shaped yoke 335 is pivotally mounted on axle 462 (FIG. 30) of cam 317. Leg 337 is secured in place by quick release pin 321. Pin 321 extends through leg 337 into one of the openings 322 formed in cam 317. The other leg 338 of yoke 335 is similarly secured to axle 462 adjacent cam 316. Arm 312 is removably secured to cam 317. The distal end of arm 312 is adjacent cam 317 and is shaped and dimensioned to interlock with leg 337 and includes an aperture (not visible) formed therethrough. In FIG. 10, quick release pin 321 extends through an aperture in leg 337 and through an aperture formed in the distal end of arm 312. Pin 231 therefore functions to help secure both leg 337 and arm 312 in position on cam 317. Arm 313 (FIG. 9) interlocks with leg 338 and is connected to cam 316 in the same manner that arm 312 is connected to cam 317. The shape and dimension of arm 313 is equivalent to that of arm 312. The shape and dimension of cam 316 is equivalent to that of cam 317. Cam 317 has a plurality of spaced apart openings 322 formed therein along a circular path or other path and that permit leg 337 and arm 312 to be secured to cam 317 at different positions. Cam 316 has a plurality of spaced apart openings formed therein along a circular path or other path and that permit leg 338 and arm 313 to be secured to cam 316 at different positions. Carriage 350 includes a plurality of wheels mounted thereon to engage and roll along the inner orthogonal walls of neck 331. As shown in FIG. 27, carriage 350 includes a pair of body members 412 and 413 held together in spaced apart relationship at one lower end by a rectangular plate 414 and at the other upper end by a rectangular plate 415. Wheels 402, 403, 404, 405 contact and roll along a first inner wall of neck 331. Wheels 400, 401, 418 contact and roll along a second inner wall of neck 331 that is opposed to, spaced apart from, and parallel to the first inner wall. Wheels 406, 407, 408, and 409 contact and roll along a third inner wall of neck 331 that is perpendicular to the first and second inner walls. Wheels 410, 411, 416, 417 contact and roll along a fourth inner wall of neck 331 that is perpendicular to the first and second inner walls and is spaced apart from and parallel to the third inner wall. Upstanding, spaced apart panels 431 and 432 (FIG. 29) are fixedly secured to plate 415. Panel 431 includes upper edge 390 and triangular guides 429 and 430. Panel 432 includes upper edge 391 (FIG. 27) and triangular guides 427 and 428. Pulley housing 421 includes wings or arms that can rest on edges 390 and 391 in the manner shown in FIG. 29. Pulley housing 422 includes wings or arms that can rest on edges 390 and 391 in the manner shown in FIG. 20. Pulley 388 is rotatably mounted in housing 421. Pulley 389 is rotatably mounted in housing 422. Wind up cable 423 is fixedly connected to housing 421. Wind up cable 424 is fixedly connected to housing 422. Wind up cable 425 is fixedly connected to the end of cable 361. Cable 363 extends over pulley 388. Cable 362 extends over pulley 389. The distal end of cable 361 extends upwardly through plate 415 and is connected to wind up cable 425. The portion of the end of cable 361 positioned above plate 415 is shaped and dimension such that it can not be pulled downwardly through plate 415. If cable 361 is pulled downwardly, it pulls plate 415 and carriage 350 downwardly away from pulley housings 421 and 422, as will be further described below. The distal end of cable 360 is fixedly connected to plate 415. If plate 415 moves downwardly in the direction of arrow W in FIG. 29, plate 415 simultaneously pulls cable 360 downwardly. Cable 363 extends through two apertures 419 (FIG. 27) formed through plate 415. During some exercises performed using the exercise machine of FIGS. 9 to 31, plate 415 will move downwardly in the direction of arrow W (FIG. 29) while cable 363 does not move. Apertures 419 permit plate 415 to move freely down along cable 363 when cable 363 is stationary. Cable 362 similarly extends upwardly through two aperture formed through plate 415. During some exercise performed using the exercise machine, plate 415 will move downwardly in the direction of arrow W (FIG. 29) while cable 362 does not move. Apertures that are formed through plate 415 and permit cable 362 to pass freely therethrough to permit plate 415 to move freely down along cable 363 when cable 362 is stationary. Finally, as noted, the distal end of cable 361 extends upwardly through an aperture formed in plate 415. Even through the distal end of cable 361 can not be pulled downwardly through plate 415, the aperture formed in plate 415 for cable 316 permits plate 415 to move downwardly along cable 361 when cable 361 is stationary. The distal end of cable 361 is connected to take up wire 425. When cable 361 is stationary and plate 415 and carriage 350 are moving downwardly in the direction of arrow W, take up wire 425 holds up cable 361 and keeps it slightly tensioned so that cable 361 does not fall downwardly in neck 331 when plate 415 moves downwardly in the direction of arrow W. Pulley housing 421 is, as noted, connected to take up wire 423. When cable 363 is stationary and plate 415 and carriage 350 are moving downwardly in the direction of arrow W (FIG. 29), take up wire 423 holds up housing 421 and cable 363 and keeps cable 363 slightly tensioned so that housing 421 and cable 363 do not fall downwardly in neck 331 when plate 415 and carriage 350 move downwardly in the direction of arrow W. Pulley housing 422 is, as noted, connected to take up wire 424. When cable 362 is stationary and plate 415 and carriage 350 are moving downwardly in the direction of arrow W, take up wire 424 holds up housing 422 and cable 362 and keeps cable 362 slightly tensioned so that housing 422 and cable 362 do not fall downwardly in neck 331 when plate 415 and carriage 350 move downwardly in the direction of arrow W. As illustrated in FIG. 11, arm 335A extends outwardly from legs 337, 338 and includes aperture 336 formed therethrough. Pulley assembly 329 is secured in FIG. 11 to a first operative storage position on the upper portion of neck 331. Spring loaded quick release pin 329 secures assembly 329 to neck 331. As will be described further below, cable 360 extends around pulley 354. Pulley assembly 329 is removed from neck 331 by pulling pin 329 to disengage from neck 331. Pulley assembly 329 can then be removably pivotally attached to arm 335A in the second operative position illustrated in FIG. 12 by installed quick release pin 330 in aperture 336. FIG. 12 also illustrates cable 260 extending around pulley 354. When pulley assembly 329 is in the first operative storage position illustrated in FIG. 11, the slack created in cable 360 allows carriage 350 to roll down the inside of hollow neck 331 to the position in the bottom of neck 331 illustrated in FIG. 11. As long as pulley assembly 329 is in the first operative position, carriage 350 remains in the bottom of neck 331 in the position illustrated in FIG. 11. When pulley assembly 320 is in the first operative storage position, arms 312 and 313 are utilized to rotate cams 316, 317 to displace the piston in chamber 334 in the manner illustrated in FIGS. 9 to 11. Arms 312 and 313 can be utilized on cams 316, 317 when cams 316, 317 are in the forward position illustrated in FIGS. 9 to 11, 30, or, when the cams are in the rear position illustrated in FIGS. 12 to 15, 31. When arms 312 and 313 (or other arms connected to cams 316, 317 or yoke 335) are used to displace cams 316, 317, the pulley assembly 329 is ordinarily in the first operative storage position so that the cable system is disconnected from yoke 335 and is not operable. In contrast, when the pulley assembly 329 is in the second operative position removably connected to yoke 335, the cable system is engaged and is (instead of arms 312, 313) employed during exercises to displace cams 316, 317. Displacing cams 316, 317 moves the piston in chamber 324. The cable system used in the exercise machine includes cables 360, 361, 362, and 363. For purposes of clarity, FIGS. 16 to 20, 25 and 26 generally only illustrate the pulleys included in the cable system, illustrate the carriage 350, illustrate at least one of cables 360 to 363, illustrate the clips 348, 349, 351, 352, 353, 357 attached to the distal ends of the cables, and illustrate the take up reels 378, 356, 346. The distal end of cable 360 is connected to clip 357. Cable 360 extends over rotatable pulleys 340, 341, 354, and 342. The proximate end of cable 360 extends through opening 420 (FIG. 27) formed through plate 415. The proximate end of cable 360 is tied off or attached to a member that prevents the proximate end from being pulled upwardly through opening 420. Consequently, pulling the proximate end of cable 360 upwardly in the direction of arrow Z (FIG. 27) pulls plate 415 and carriage 350 upwardly in the direction of arrow Z. When pulley assembly 329 is moved to the first operative storage position on neck 331, slack is produced in cable 360. This slack is quickly removed because gravity causes carriage 350 to roll downwardly along the inside of neck 331 to the position in the bottom of neck 331 illustrated in FIG. 11. The distal end of cable 361 is connected to clip 353. As is illustrated in FIG. 16, cable 361 extends over rotatable pulleys 372 and 386. The proximate end of cable 361 extends upwardly through an opening formed through plate 415, said opening extending through plate 415 in the same manner that openings 419 and 420 extend through plate 415. The proximate end of cable 361 is tied off or attached to a member that prevents the proximate end from being pulled downwardly through the opening in plate 415 through which cable 361 extends. Consequently, pulling the proximate end of cable 361 downwardly in the direction of arrow X1 (FIG. 16) pulls plate 415, carriage 350, and the proximate end of cable 360 downwardly in the direction of arrow X1 because the tied off proximate end of cable 361 presses against plate 415 and generates forces acting in the direction of arrow X1. The proximate end of cable 361 is also connected to take-up reel line 425. Line 425 and reel 378 maintain a slight upward pull or tension on cable 361. Cables 360 and 361 are utilized during leg flexion exercises. One end of a connector cable 361A (FIG. 14) is attached to clip 353. The other end of a connector cable 361A is connected to leg flexion apparatus 302 that pivots upwardly and downwardly about one end of bench 301 between the operative positions illustrated in FIG. 14. The first normal “at rest” operative position of flexion apparatus 302 is illustrated in FIG. 14 by solid lines. The second lifted/pivoted operative position of flexion apparatus 302 is illustrated in ghost outline in FIG. 14 by dashed lines 302. In use, an individual sits on the end of bench 301 with his feet positioned under cylindrical cushions 303 or 370 in conventional fashion. The user then attempts to lift the cushions in the directions indicated by arrow D and E. FIGS. 15 and 16 illustrate the position of cable 360, pulley 343, carriage 350, and cable 361 when apparatus 302 is in the normal “at rest” operative position illustrated in FIG. 9. When the user employs his quad leg muscles to lift his feet and move apparatus 302 upwardly from the “at rest” operative position to the second lifted/pivot operative position, clip 353 moves in the direction of arrow H (FIG. 16) and cable 361 pulls carriage 350 downwardly from the position illustrated in FIG. 15 to the position illustrated in FIG. 17. Further, when carriage 350 is pulled downwardly, plate 415 functions to pull the proximate end of cable 360 downwardly. The distal end of cable 360 can not be pulled in the direction of arrow E over pulley 340. Clip 357 functions as a stop (as will be described, clip 357 and cable 360 can be pulled downwardly in a direction opposite that of arrow E). Consequently, when the proximate end of cable 360 is pulled downwardly, cable 360 is pulled over free wheeling pulley 342, and is pulled over free wheeling pulley 343 to lift pulley assembly 329 and yoke 335 upwardly in the direction of arrow G in FIG. 16. Lifting yoke 335 in the direction of arrow G also lifts the nose of cams 316, 317 upwardly (FIG. 15) in the general direction of arrow G. Lifting cams 316, 317 in the direction of arrow G upwardly displaces belts 323 and 323A. Upwardly displacing belts 323 and 323A causes arm 328 to be upwardly displaced in the direction of arrow B in the manner shown in FIG. 11. Upwardly displacing arm 328 moves the piston further into chamber 324, compressing air in chamber 324 and increasing the resistance generated by the air. When apparatus 302 is moved from its second operative position back to its first normal operative position, the foregoing process is reversed and pulley 354, carriage 350, cable 361 and clip 353 return to the position shown in FIG. 16. FIG. 16A illustrates the position of carriage 350 at the beginning of the leg flexion exercise, when apparatus 302 is in the normal “at rest” operative position illustrated in FIG. 9. FIG. 17A illustrates the position of carriage 350 during the leg flexion exercise when apparatus 302 has been upwardly displaced to the position shown in ghost outline in FIG. 14. When carriage 350 moves from the position shown in FIG. 16 to the position shown in FIG. 17, take up wire 425 unwinds from spring loaded take-up reel 378. Reel 378 maintains a slight tension on wire 425. When carriage 350 moves from the position shown in FIG. 17 back to the position shown in FIG. 16, reel 378 maintains a tension on wire 425 and, in the manner of a spring loaded tape measure, reels wire 425 back into reel 378. In FIG. 18, one end of the platform pulley cable 362 is connected to clip 348. The other end is connected to clip 349. Cable 362 extends from clip 348 sequentially over free wheeling pulleys 373, 374, 371, 389, 387, 384, and 385. FIG. 18 illustrates the position of clips 348 and 349, of carriage 350, of pulley 389, of pulley 354, and of cable 360 when clips 348 and 349 are in their first normal “at rest” operative position. The second lifted/pivoted operative position of clips 348 and 349 is illustrated in FIG. 19. In FIG. 19, clip 349 has been moved in the direction of arrow I (FIG. 18) to the position shown in FIG. 19. In FIG. 19, clip 348 has been moved in the direction of arrow J to the position shown in FIG. 19. In use, an individual lays on his back on bench 301 with head on the end of bench 310 nearest neck 331. As would be appreciated by those of skill in the art, the individual can recline or sit on bench 310 in other positions. A bar(s) or handles (not shown) are attached to clips 348 and 349. The individual grasps the handles. The user then attempts to lift the handles in the directions indicated by arrow I and J. FIG. 18 illustrates the position of cable 362, pulley 354, carriage 350, pulley 389, and clips 348 and 349 when clips 348 and 349 are in the normal “at rest” operative position. When the user employs his arm and chest muscles to lift the handles attached to clips 348, 349 to the second operative position illustrated in FIG. 19 and to move clips 348 and 349 upwardly in the directions indicated by arrows I and J, cable 362 pulls pulley 389 and carriage 350 downwardly from the position illustrated in FIG. 18 to the position illustrated in FIG. 19. Further, when pulley 389 and carriage 350 are pulled downwardly, plate 415 functions to pull the proximate end of cable 360 downwardly. The distal end of cable 360 can not be pulled in the direction of arrow E over pulley 340. Clip 357 functions as a stop (as will be described, clip 357 and cable 360 can be pulled downwardly in a direction opposite that of arrow E). Consequently, when the proximate end of cable 360 is pulled downwardly, cable 360 is pulled over free wheeling pulley 342, and is pulled over free wheeling pulley 354 to lift pulley assembly 329 and yoke 335 upwardly in the direction of arrow G in FIG. 18. Lifting yoke 335 in the direction of arrow G also lifts the noses 316C, 317C of cams 316, 317 in the general direction of arrow G. Lifting cams 316, 317 in the direction of arrow G upwardly displaces belts 323 and 323A. Upwardly displacing belts 323 and 323A causes arm 328 to be upwardly displaced in the direction of arrow B in the manner shown in FIG. 11. Upwardly displacing arm 328 moves the piston further into chamber 324, compressing air in chamber 324 and increasing the resistance generated by the air. When the individual permits clips 348, 349 and the handles attached thereto to move downwardly in directions opposite that of the directions indicated by arrows J and 1, respectively, back to their first normal operative position, the foregoing process is reversed and pulley 389, carriage 350, cable 362 and clips 348 and 349 return to the positions depicted in FIG. 18. FIG. 18A illustrates the position of carriage 350 at the beginning of the platform pulley cable 362 exercise described immediately above, when clips 348 and 349 are in the normal “at rest” operative position illustrated in FIG. 18. FIG. 19A illustrates the position of carriage 350 during the platform pulley cable 362 exercise when clips 348 and 349 have been upwardly displaced to the second operative position illustrated in FIG. 19. When carriage 350 moves from the position shown in FIG. 18 to the position shown in FIG. 19, take up wire 424 unwinds from spring loaded take-up reel 356. Reel 356 maintains a slight tension on wire 424. When carriage 350 moves from the position shown in FIG. 19 back to the position shown in FIG. 18, reel 356 maintains a tension on wire 424 and, in the manner of a spring loaded tape measure, reels wire 424 back into reel 356. In FIG. 20, one end of the mid-range pulley cable 363 is connected to clip 351. The other end is connected to clip 352. Cable 363 extends from clip 351 sequentially over free wheeling pulleys 380, 382, 345, 388, 344, 383, and 381. FIG. 20 illustrates the position of clips 351 and 352, of carriage 350, of pulley 388, of pulley 354, and of cable 360 when clips 351 and 352 are in their first normal “at rest” operative position. The second pulled operative position of clips 351 and 352 is illustrated in FIG. 21. In FIG. 21, clip 351 has been pulled in the direction of arrow L (FIG. 20) to the position shown in FIG. 21. In FIG. 21, clip 352 has been moved in the direction of arrow K (FIG. 20) to the position shown in FIG. 21. In use, an individual sits on bench 301 facing neck 331. As would be appreciated by those of skill in the art, the individual can recline or sit on bench 310 in other positions. A bar(s) or handles (not shown) are attached to clips 351 and 352. The individual grasps the handles. The user then attempts to pull the handles (and clips 351 and 352) in the directions indicated by arrows L and K. FIG. 20 illustrates the position of cable 363, pulley 354, carriage 350, pulley 388, and clips 351 and 352 when clips 351 and 352 are in the normal “at rest” operative position. When the user employs his arm and chest muscles to pull the handles attached to clips 351, 352 to the second operative position illustrated in FIG. 21 and to move clips 351 and 352 outwardly in the directions indicated by arrows L and K, respectively, cable 363 pulls pulley 388 and carriage 350 downwardly from the position illustrated in FIG. 20 to the position illustrated in FIG. 21. Further, when pulley 388 and carriage 350 are pulled downwardly, plate 415 functions to pull the proximate end of cable 360 downwardly. The distal end of cable 360 can not be pulled in the direction of arrow E over pulley 340. Clip 357 functions as a stop (as will be described, clip 357 and cable 360 can be pulled downwardly in a direction opposite that of arrow E). Consequently, when the proximate end of cable 360 is pulled downwardly, cable 360 is pulled over free wheeling pulley 342, and is pulled over free wheeling pulley 354 to lift pulley assembly 329 and yoke 335 upwardly in the direction of arrow G in FIG. 16. Lifting yoke 335 in the direction of arrow G also lifts the noses of cams 316, 317 upwardly in the general direction of arrow G. Lifting cams 316, 317 in the direction of arrow G upwardly displaces belts 323 and 323A. Upwardly displacing belts 323 and 323A causes arm 328 to be upwardly displaced in the direction of arrow B in the manner shown in FIG. 11. Upwardly displacing arm 328 moves the piston further into chamber 324, compressing air in chamber 324 and increasing the resistance generated by the air. When the individual permits clips 351, 352 and the handles attached thereto to move back toward neck 331 in directions opposite that of the directions indicated by arrows L and K, respectively, back to their first normal operative position, the foregoing process is reversed and pulley 388, carriage 350, cable 363 and clips 351 and 352 return to the positions depicted in FIG. 20. FIG. 20A illustrates the position of carriage 350 at the beginning of the mid-range pulley cable 363 exercise described immediately above, when clips 351 and 352 are in the normal “at rest” operative position illustrated in FIG. 20. FIG. 21A illustrates the position of carriage 350 during the platform mid-range pulley cable 363 exercise when clips 351 and 352 have been outwardly displaced to the second operative position illustrated in FIG. 21. When carriage 350 moves from the position shown in FIG. 20 to the position shown in FIG. 21, take up wire 423 unwinds from spring loaded take-up reel 346. Reel 346 maintains a slight tension on wire 423. When carriage 350 moves from the position shown in FIG. 21 back to the position shown in FIG. 20, reel 346 maintains a tension on wire 423 and, in the manner of a spring loaded tape measure, reels wire 423 back into reel 346. Cable 360 is utilized during a lat exercise. A bar 392 including handles 393 and 394 is connected to clip 357. Bench 301 is removed, leaving only platform 307 as illustrated in FIG. 22. The first normal “at rest” operative position of bar 392 and clip 357 is illustrated in FIG. 23 and in FIGS. 22 and 24 in solid lines. The second pulled operative position of bar 392 and clip 357 is illustrated in ghost outline in FIGS. 22 and 24 by dashed lines 392. In use, an individual stands on platform 307 beneath bar 292 and grasps each handle 393, 394 with an opposite one of his hands in conventional fashion. The user then attempts to pull bar 392 downwardly in the directions indicated by arrow N in FIG. 24. FIG. 25 illustrates the position of cable 360, pulley 354, carriage 350, and cable 361 when cable 360 is in the normal “at rest” operative position. When the user employs his arm and lat muscles to pull bar 393 and clip 357 downwardly from the “at rest” operative position to the second lifted/pivot operative position illustrated in FIG. 26, clip 357 and bar 393 move downwardly in the direction of arrow N (FIG. 24) and cable 369 pulls pulley 354 upwardly in the direction of arrow G (FIG. 25). Carriage 350 and free wheeling pulley 342 do not move. Consequently, when the distal end of cable 360 is pulled downwardly in the direction of arrow N, cable 360 is pulled over free wheeling pulleys 341 and 342, and is pulled over free wheeling pulley 354 to lift pulley assembly 329 and yoke 335 upwardly in the direction of arrow G in FIG. 16. Lifting yoke 335 in the direction of arrow G also lifts the noses 316C, 317C of pivoting cams 316, 317 upwardly in the general direction of arrow G. Lifting cams 316, 317 in the direction of arrow G upwardly displaces belts 323 and 323A. Upwardly displacing belts 323 and 323A causes arm 328 to be upwardly displaced in the direction of arrow B in the manner shown in FIG. 11. Upwardly displacing arm 328 moves the piston further into chamber 324, compressing air in chamber 324 and increasing the resistance generated by the air. When clip 357 and bar 393 are moved from their second operative position back to their first normal operative position, the foregoing process is reversed and pulley 354, cable 360 and clip 357 return to the position shown in FIG. 25. When bar 393 and clip 357 move from the position shown in FIG. 25 to the position shown in FIG. 26, take up wires 423 to 425 do not move from the position illustrated in FIG. 29, and cable 361 does not move from the position illustrated in FIG. 16. The proximate end of cable 360 generates an upward force on plate 415 that maintains carriage 350 in the position illustrated in FIGS. 15, 16, 18, 20, 22A, 23, 26 and 28. In general, any resistance exercise performed by an individual, whether with free weights or on a machine, is comprised of a negative part and a positive part. The positive part of the exercise occurs when the individual is moving the weight upwardly against gravity. The negative part of the exercise occurs when the individual is moving the weight downwardly “with” gravity. For example, during a squat, the positive part of the exercise occurs when the individual is using his or her legs to move upwardly. The negative part of the exercise occurs when the individual is using his or her legs but is moving downwardly. An individual normally can handle more weight during the negative part of an exercise. Typically, the amount of weight an individual can handle during the negative part of an exercise is about forty percent more than the weight the individual can handle during the positive part of an exercise. One goal of the invention is to provide an exercise machine than facilitates providing an individual with more weight during the negative portion of the exercise than is provided during the positive portion of the exercise. At the same time, the exercise machine preferably facilitates an individual stopping an exercise to rest when the individual reaches during the positive part of an exercise failure and can no longer perform the positive part of an exercise at the weight or resistance originally selected. A common practice is for an individual to have an assistant that helps the individual continue performing the negative part of an exercise after the individual has reached failure while performing the positive part of the exercise. For example, during a squat using free weights, the individual may be able to perform the negative part of the exercise and go down to a sitting position. The assistant helps the individual perform the positive part of the exercise by lifting some or all of the weight. If, however, heavy weights are being used, there is a significant risk an accident or injury will occur, even when an assistant is present. One practice commonly utilized to reduce the risk of injury is to reduce the amount of weight used while the individual continues the exercise. Decreasing the weight permits more repetitions to be performed. A disadvantage of this procedure is that when free weights and weight stack machines are utilized, the individual has to stop performing and interrupt the exercise to change the weights. Such an interruption can be significant. If, for example, the individual is lying on a bench to perform an exercise, the individual has to stand up, go to the weight stack, alter the weight stack, etc. Some exercise machine may permit the weight used to be altered by pushing manually buttons or valve controls. One disadvantage of such a machine is that the individual must maintain his arms and legs in certain positions in order to be able to reach the controls while performing an exercise. Another disadvantage is that requiring the individual to move his hands or fingers to alter the magnitude of weight being displaced during an exercise can be uncomfortable and it can force the individual to release part of his grip, interfering with the proper technique necessary to correctly perform the exercise. The exercise machine of the invention offers solutions to the foregoing problem because an individual using the machine does not have to worry about manipulating controls while he performs an exercise. The computer control system manages the valves and the individual can use his voice, can stop during the exercise, or can pause during the exercise, etc. to trigger changes in the resistance offered by the exercise machine, even when exercises are performed using cables in the exercise machine. The exercise machine of the invention intentionally preferably avoids running pneumatic hoses to handles gripped by an individual during an exercise, and also intentionally preferably avoids placing control buttons on such handles. Control buttons, pneumatic hoses, and other controls can, if desired, be utilized at or near handles grasped by an individual during an exercise, but such are not preferred. In prior art pneumatic cable machines, the buttons to control the resistance are positioned away from the handles because it is impractical to run pneumatic hoses to the handles and to position control buttons on the handles. Since the control buttons are positioned away from the handles, a user typically must halt the exercise to use the buttons. The exercise machine of the invention avoids this problem. The exercise machine of the invention facilitates the performance of a variety of exercises, both with and without cables. One particular advantage of the carriage 350 is that it facilitates maintaining cables 361, 362, 363 inside the exercise machine and out of view. Carriage 350 also facilitates having cable ends positioned at different locations on the exercise machine, facilitating the use of cables to perform different kinds of exercises. One particular advantage of cams 316, 317 is that they can be rotated between a forward position (FIG. 11) and a rearward position (FIG. 12) to facilitate the performance of different exercises. When cams 316, 317 (if desired, only a single cam need be used) are in the forward position, the cam be used to perform exercises like a bench press that require arms 312, 313 to be pressed upwardly. When cams 316, 317 are in the rearward position, the cam can be used to perform exercises that require arms 312, 313 to be pulled or pushed downwardly. For example, when cams 316, 317 are in the rearward position, arms 312, 313 can be connected to the cams such that arms 312, 313 are in the same general position as depicted in FIG. 10. This would permit an exercise to be performed that would require arms 312 and 313 to be pulled downwardly and that would, when arms 312, 313 were pulled downwardly, cause cams 316, 317 to pivot upwardly in the direction indicated by arrow Q in FIG. 31. When cams 316, 317 were so pivoted, the piston would be displaced further into chamber 334, increasing the resistance produced by compressed air in chamber 334. Moving cams 316, 317 to the rearward position illustrated in FIG. 12 also, as earlier described, facilitates the use of pulley 354 to perform various cable exercises. Another advantage of cams 316, 317 is that they facilitate the use of an accumulator 310 having a smaller volume. A smaller accumulator 310 typically requires less compressed air to operate, which extends the life of the compressor used in conjunction with the exercise machine. One advantage of the control system of the invention is that the controller 311 can record the variables associated with an exercise routine. Such variables can, without limitation, include the number of repetitions of an exercise programmed or actually performed by an individual, include the number of sets of an exercise programmed or performed (where a set comprises a defined number of repetitions of an exercise), include the particular exercises programmed or actually performed, include the cadence programmed or actually performed, include how long it took to complete each repetition or set or exercise, include how long it took to complete the negative and positive portions of an exercise, include graphs that depict any of the foregoing variables and that can, for example, tell a user at what point in a repetition, or set, or exercise the user changed the weight (resistance) produced by the exercise machine, and can include any desired statistical analysis that can be used to evaluate the effectiveness of an exercise program, evaluate the success of an individual in following an exercise routine, alter an existing exercise program, design a new exercise program, evaluate the fitness progress being made by an individual, or to accomplish any other desired goal connected with the performance of the exercise machine or effectiveness of an exercise or exercise routine for an individual. Another advantage of the exercise machine of the invention is that an exercise can be initiated from a beginning position in which the arms and/or legs are fully extended with the bar overhead and in which there is little or no resistance acting on the individual's arms or legs. The bench press exercise is used to discuss this feature of the invention. For purposes of discussion, in the beginning position of an exercise the individual's arms are fully extended over his head holding a barbell. When a bench press is performed with free weights, the individual can lift the bar bell off the support rack with his arms substantially extended in the beginning position. The individual does not have to lift weight to move his arms from a contracted or bent position near his body to the beginning position with his arms extended above his body. In contrast, when an individual is attempting a bench press using a machine that connects with cables a bar or handles to a weight stack, the individual must begin the exercise with his arms bent and hands near his chest and must force the bar or handles upwardly and displace the weight stack upwardly in order for the individual's arms to reach the beginning position with his arms extended over his head. Consequently, in order to reach the beginning position of the exercise, the individual must use muscular exertion to overcome the weight stack. With these kind of machines the user cannot achieve desired “over stretch” that can be achieved with free weights. For example, if the user is doing a bench press with dumbbells, when the user lowers the dumbbells, he can lower the dumbbells to an “over stretch” position in which the dumbbells are a little bit lower than his chest. Or, if the user is using a barbell, he can, in an “over stretch” position, permit the barbell to slightly compress his chest. It would be difficult on a conventional weight stack machine to achieve such over stretch positions. The exercise machine of the invention permits an individual to begin a bench press in the same manner as free weight, i.e., without the individual having to overcome resistance in order to extend his arms to the beginning position of the exercise. This is possible because the machine of the invention can be programmed to produce little or no resistance when, for example, the individual grasps handles 314 and 315 (FIG. 9) and upwardly displaces arms 312 and 313 to extend his arms to the beginning position of the exercise. The following examples are given by way of illustration, and not limitation, of the invention. EXAMPLE 1 The microcontroller, as do most computers, keeps track of and “knows” the calendar date and time of day. The user elects to do a bench press with the cams 316, 317 in the forward position shown in FIG. 9. The user uses keypad 38 to enter alphanumeric characters that identify him to the machine (as, for example, “USER NO. 1”) and that identify to the machine the exercise being performed. This information permits the record keeping portion of the microcontroller to generate a record indicating that User No. 1 performed a bench press on the machine on a certain date and at a certain time of day. Using the keypad 38, the user also informs the microcontroller that during the first set of repetitions the weight during the positive and negative portions of the exercise will be 200 pounds, that during the second set of repetitions the weight during the positive portion of the exercise will be one hundred and twenty-five pounds and the weight during the negative portion of the exercise will be two hundred pounds, and that during the third set of repetitions the weight during the positive and negative portions of the exercise will be one hundred pounds. The user enters this information with keypad 38 by entering an appropriate code, followed by the weight designations two hundred, one hundred and twenty-five, and one hundred pounds. The control algorithm of the microcontroller uses the control model to calculate for each weight (i.e., for two hundred pounds, for one hundred and twenty-five pounds, and one hundred pounds) the pressure values set forth in TABLES I, II, III, respectively. The user also enters with keypad 38 a code that informs microcontroller 49 that five repetitions (where one repetition comprises lowering and then raising arms 312 and 313) will be performed during each of the three sets. The user also enters with keypad 38 a code that informs the microcontroller that the user will issue the voice command “BEGIN” to initiate the bench press exercise, that when user has displaced the arms 312, 313 to the raised position of FIG. 10 just before the user begins the exercise, the weight (resistance) will only be ten pounds and will increase to 200 pounds once the user says “BEGIN”, that the machine will automatically change the weight from two hundred pounds to one hundred and twenty-five pounds after the first five repetitions (i.e., the first set) are complete, and that after the first ten repetitions are completed the change in weight from one hundred and twenty-five pounds to one hundred pounds will be done by the user giving the voice command “NEXT”. The user also enters with keypad 30 a code that informs the microcontroller that the cadence for the exercise will be one-half repetition every three seconds. Consequently, the user intends to take three seconds to lower the handles 312 and 313 to the position shown in FIG. 9 and to take three seconds to raise the handles 312 and 313 to the position shown in ghost outline in FIG. 9 and also shown in FIG. 10. The user is not required to input a cadence to be monitored by the microcontroller, but elects to do so. Or, the microcontroller can automatically select a particular metronome cadence that will play during an exercise, if the user turns on the metronome. Or, the microcontroller can automatically select a particular cadence that will play regardless of whether the user selects or turns on the metronome. Or, if the machine detects that the user does not keep up with a particular cadence or goes too fast for a particular cadence, the microcontroller can automatically reduce or increase the weight. Or, the machine can have one cadence for the negative portion of the exercise and the machine can have another cadence for the position portion of the exercise. Or, for a particular cadence, the user can decide how many metronome counts he will use for the negative portion of the exercise and how many metronome counts he will use for positive portion of the exercise. The user also enters with keypad 30 information that requires the microcontroller to automatically reduce the weight to ten pounds if the user takes more (or less) than one-half second to complete an up or a down movement while pushing or lowering arms 312 and 313, respectively. The user is not required to input this information. The machine can be programmed to take no action if the user does not complete the normal range of motion during the exercise, or, the machine can be preprogrammed to reduce the weight automatically if it detects a particular deviation from the desired cadence. The user also enters in keypad 30 data that informs the microcontroller that the user will, when he reciprocates arms 312 and 313 up and down, be displacing the piston between its 40% and 70% positions in its range of movement in the pressure chamber 334. The user is not required to input this information. If the user does not input this information, the machine monitors the first one or two repetitions and determines the range of movement of the piston in chamber 334. The user also enters in keypad 30 data that informs the microcontroller that if the user pauses for more than two seconds at the 40% or 70% positions of the piston, or at any position therebetween, the microcontroller will automatically lower the weight (resistance) to ten pounds. The user need not input this information. The machine can be preprogrammed not to take any action if the user pauses, or, can be programmed to automatically lower the resistance if the user pauses at a particular position for more than a selected period of time. The user also enters in keypad 30 data that informs the microcontroller that if at any time during the exercise the user does not complete his full programmed range of motion (e.g., if during the third repetition the user displaces the piston to only 60% in chamber 334, instead of to 70%), the microcontroller will reduce the weight to ten pounds. The user need not input this information. The machine can be preprogrammed to automatically lower the resistance of the user does not complete his full range of motion. The machine can also be programmed not to take any action is the user does not complete his full range of motion. The user lies on bench 301 on his back with his head on the bench near neck 331. The user grasps each handle 314, 315 with a different one of his hands, and lifts arms 312 and 313 upwardly from the position shown in FIG. 9 to the position shown in ghost outline in FIG. 9. When the user lifts arms 312 and 313 upwardly in this manner, the microcontroller operates valves 11 and 12 to maintain a weight (resistance) of ten pounds. When the user has lifted the arms upwardly and is holding the arms at a fixed position in which the piston is at the 70% position in chamber 334, the user begins the exercise with the verbal command “BEGIN”. On receipt of this command, the microcontroller begins operating the valves to adjust the weight to two hundred pounds. The user completes the first five repetitions (i.e., the first set) of the exercise adhering to the programmed cadence of one-half repetition per one half second and adhering to a displacement of arms 312 and 313 that displaces the piston between its 40% and 70% positions. After completing the first five repetitions of the exercise the user begins the next five repetitions (i.e., the second set) at the programmed cadence of one-half repetition per one half second. During the positive portions of the second set of repetitions, the machine automatically begins reducing the weight to one hundred and twenty-five pounds during the positive portion of each repetition. The user completes the second set of repetitions of the exercise (i.e., repetitions 6 to 10) adhering to the programmed cadence of one-half repetition per one half second and adhering to a displacement of arms 312 and 313 that displaces the piston between its 40% and 70% positions. After completing the second set first five repetitions of the exercise the user said “NEXT” and begins the next five repetitions (i.e., the third set) at the programmed cadence of one-half repetition per one half second. At the beginning of the third set, the machine automatically begins reducing the weight to one hundred pounds. During the positive portion of the second repetition in the third set, the user pauses for more than two seconds with the piston at the 60% position in chamber 334. The microcontroller automatically reduces the weight (resistance) to ten pounds. EXAMPLE II Example I is repeated except that cams 316 and 317 are in the rearward position illustrated in FIG. 12 and arms 312, 313 are connected to cams 317, 316, respectively, so arms 312 and 313 are generally in the position illustrated in FIG. 10. Similar results are obtained. However, when the cams 316 and 317 and arms 312 and 313 are in the general orientation shown in FIG. 9, pushing arms 312 and 313 upwardly causes the outer ends or noses of cams 316 and 317 to pivot upwardly and increases the pressure in chamber 334. In contrast, when cams 316 and 317 are in the rearward orientation of FIG. 12 and arms 312 and 313 are in the general position shown in FIG. 10, pulling arms 312 and 313 downwardly increases the pressure in chamber 334 because pulling arms 312 and 313 downwardly causes the outer ends or noses of cams 316 and 317 to pivot upwardly. An alternate embodiment of the invention is illustrated in FIGS. 32 to 40 and includes a sleeve 400 that is movably mounted on neck 331. Sleeve 400 includes a quick release pin, set screws 401 and 407, accumulator 408, and a handle 404. Set screws 401 and 407 are tightened and bear against neck 331. A strap 402 with spaced apart apertures 405, 406 is fixedly secured to neck 331. Sleeve 400 is positioned along neck 331 by manually turning set screws 401 and 407 to disengage the set screws from neck 331, by grasping handle 404 with a first hand, by outwardly pulling quick release pin 403 with the a second hand, by using the first hand to move handle 404 (and sleeve 400) upwardly or downwardly 407 along neck 331 until quick release pin 403 is aligned with a desired aperture 405 or 406, by releasing quick release pin 403 so the end of the pin enters and engages the desired aperture, and by manually releasing pin 403. As is illustrated in FIGS. 37 and 38, the cams 317, arms 312, piston assembly 328, tank 408 of pressurized gas, and yoke 335 can each be mounted on and move upwardly and downwardly with sleeve 400. A particular advantage of sleeve 400 is that altering the position of sleeve 400 on neck 331 also alters the elevation of the pivot point about which arms 312 and cams 317 rotate, which alters the angle of the arms 312 with respect to an individual sitting or reclining on bench 301. This facilitates the use of the apparatus of the invention in using different exercises, in exercising different muscles, or in exercising different portions of the same muscle groups. This also facilitates providing a different set of starting points for arms 312 by using pins 321 to change the position of arms 213 on cams 316, 317. Altering the position of sleeve 400 also similarly alters the elevation of the pivot point about which yoke 335 pivots. Having described my invention in such terms as to enable those of skill in the art to make and practice it, and having described the presently preferred embodiments thereof, | 20040420 | 20080819 | 20051020 | 80222.0 | 0 | MATHEW, FENN C | ELECTRONIC SYSTEM TO BE APPLIED IN VARIABLE RESISTANCE EXERCISE MACHINE | SMALL | 0 | ACCEPTED | 2,004 |
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10,828,059 | ACCEPTED | Automatic fiber yield system and method | The present invention is a system and method for the automatic control of a debarking system for use in a chip mill, paper mill, or the like. The present invention comprises one or more programmable logic controllers (PLCs) that receive input from ultrasonic sensors that measure the quantity of wood present at various locations within the system. Based on this data, the PLCs reference look-up tables that contain information on start, stop, speed up, and slow down times for various system components based on such criteria as wood variety and season. The control system optimizes the fiber yield from the debarking system while also reducing mechanical wear on components of the system by reducing the time at which components are run at high speed. | 1. A controller for a debarking system, comprising a controller circuit, one or more sensors in communication with said controller circuit, and a look-up table in communication with said controller circuit, wherein said sensors are positioned with respect to said debarking system to measure the quantity of material at one or more locations within said debarking system; said look-up tables comprise data concerning one or more of conveyor infeed delay times, conveyor delay to slow times, conveyor delay to stop times, conveyor sensor depths, drum slow speeds, drum fast speeds, drum delay to slow times, drum delay to stop times, conveyor slow speeds, conveyor fast speeds, and conveyor sensor depths; and wherein said control circuit comprises inputs for receiving data from said sensors, computational functionality for determining which of a plurality of values in said look-up table corresponds to a given datum from one of said sensors, reading functionality for reading one of said values from said look-up table, and switching functionality to manipulate the debarking system in a manner corresponding to said one of said values. 2. The controller of step 1, further comprising a plurality of look-up tables, and wherein said control circuit further comprises functionality for inputting at least one of wood variety data and date data, and further comprises additional computational functionality to select one of said look-up tables from said plurality of look-up tables based upon at least one of said wood variety data and date data. 3. A debarking system, comprising: (a) an infeed conveyor; (b) a rotating drum positioned after said infeed conveyor to receive material; (c) an infeed sensor located at said infeed conveyor operable to determine if material is present at said infeed conveyor; (d) one or more look-up tables, wherein said look-up tables comprise values concerning one or more of conveyor infeed delay times, conveyor delay to stop times, and conveyor sensor depths; and (e) a control circuit in communication with said infeed sensor and said look-up tables, wherein said control circuit comprises input means for receiving data from said infeed sensor, computing means for determining which of said values in said look-up tables corresponds to a datum from said infeed sensor, reading means for reading a value from said corresponding look-up table, and switching means to manipulate at least one of a start and a stop time of said infeed conveyor. 4. The debarking system of claim 3, further comprising a rotating drum and a drum sensor located near said rotating drum and operable to determine the level of material present in said drum, wherein said look-up tables further comprise values concerning one or more of drum slow speeds, drum fast speeds, drum delay to slow times, and drum delay to stop times, and wherein said control circuit is in communication with said drum sensor, and said control circuit comprises input means for receiving data from said drum sensor, computing means for determine which of said values in said look-up tables corresponds to a datum from said drum sensor, and switching means to manipulate at least one of a speed and stop time for said rotating drum. 5. The debarking system of claim 4, further comprising a discharge conveyor and a discharge conveyor sensor located near said discharge conveyor and operable to determine if material is present at said discharge conveyor, wherein said look-up tables further comprise values concerning one or more of discharge conveyor slow speeds, discharge conveyor fast speeds, discharge conveyor delay to slow times, discharge conveyor delay to stop times, and discharge conveyor sensor depths, and wherein said control circuit is in communication with said discharge conveyor sensor, and said control circuit comprises input means for receiving data from said discharge conveyor sensor, computing means to determine which of said values in said look-up tables corresponds to a datum from said discharge conveyor means, and switching means to manipulate at least one of a speed, start time, and stop time for said discharge conveyor. 6. The debarking system of claim 5, further comprising a chipper feed conveyor and a chipper feed conveyor sensor located near said chipper feed conveyor and operable to determine if material is present at said chipper feed conveyor, wherein said look-up tables further comprise values concerning one or more of chipper feed conveyor slow speeds, chipper feeder conveyor fast speeds, chipper feeder conveyor delay to slow times, chipper feeder conveyor delay to stop times, and chipper feeder conveyor sensor depths, and wherein said control circuit is in communication with said chipper feeder conveyor sensor, and said control circuit comprises input means for receiving data from said chipper feeder conveyor sensor, computing means to determine which of said values in said look-up tables corresponds to a datum from said chipper feeder conveyor means, and switching means to manipulate at least one of a speed, start time, and stop time for said chipper feeder conveyor. 7. The debarking system of claim 6, wherein said control circuit further comprises functionality for inputting at least one of wood variety data and date data, and further comprises additional computational functionality to select one of said look-up tables based upon at least one of said wood variety data and date data. 8. A method for controlling a debarking system, comprising the method steps of: (a) sensing one of the presence of material, the absence of material, and a level of material within the debarking system, and generating a sensor signal dependent thereupon; (b) receiving the sensor signal and calculating a location to access a control value in a look-up table based upon the sensor signal; (c) accessing the control value in the look-up table and calculating a control function based upon the control value; (d) sending a control signal to the debarking system based upon the control value. 9. The method of claim 8, further comprising the steps of: (a) receiving an operator signal indicating one of one or more of the variety of the wood being processed and the time at which the processing is being performed; and (b) calculating which of a plurality of look-up tables to access based upon one or more of the variety of wood being processed in the debarking system and the time at which the processing is being performed. 10. The method of claim 8, wherein said control value comprises one of conveyor infeed delay times, conveyor delay to slow times, conveyor delay to stop times, conveyor sensor depths, drum slow speeds, drum fast speeds, drum delay to slow times, drum delay to stop times, conveyor slow speeds, conveyor fast speeds, and conveyor sensor depths. 11. A debarking control method, comprising the steps of: (a) sensing at an infeed conveyor the presence of material; (b) turning on the infeed conveyor if material is sensed at the infeed conveyor; and (c) turning off the infeed conveyor if no material is sensed at the infeed conveyor for a period of time, wherein an infeed delay value corresponding to the period of time is stored in a look-up table and accessed by a control circuit. 12. The debarking method of claim 11, further comprising the steps of: (a) sensing at a debarking drum at least one of the presence and quantity of material in the debarking drum; (b) turning the debarking drum to a higher speed if material is sensed in the debarking drum; and (c) turning the debarking drum to a lower speed if no material is sensed in the debarking drum for a period of time, wherein a drum delay to slow value corresponding to the period of time is stored in a look-up table and accessed by a control circuit. 13. The debarking method of claim 12, further comprising the step of turning the debarking drum off if no material is sensed in the debarking drum for a period of time, wherein a drum delay to stop value corresponding to the period of time is stored in a look-up table and accessed by a control circuit. 14. The debarking method of claim 12, further comprising the step of varying the speed of the debarking drum based on the quantity of material sensed in the debarking drum. 15. The debarking method of claim 13, further comprising the steps of: (a) sensing at a discharge conveyor at least one of the presence and quantity of material in the debarking drum; (b) turning the discharge conveyor to a higher speed if material is sensed at the discharge conveyor; and (c) turning the discharge conveyor to a lower speed if no material is sensed in the discharge conveyor for a period of time, wherein a discharge conveyor delay to slow value corresponding to the period of time is stored in a look-up table and accessed by a control circuit. 16. The debarking method of claim 15, further comprising the step of turning the discharge conveyor off if no material is sensed at the discharge conveyor for a period of time, wherein a discharge conveyor delay to stop value corresponding to the period of time is stored in a look-up table and accessed by a control circuit. 17. The debarking method of claim 15, further comprising the step of varying the speed of the discharge conveyor based on the quantity of material sensed in the discharge conveyor. 18. The debarking method of claim 16, further comprising the steps of: (a) sensing at a chip feed conveyor at least one of the presence and quantity of material in the chip feed conveyor; (b) turning the chip feed conveyor to a higher speed if material is sensed at the chip feed conveyor; and (c) turning the chip feed conveyor to a lower speed if no material is sensed in the chip feed conveyor for a period of time, wherein a chip feed conveyor delay to slow value corresponding to the period of time is stored in a look-up table and accessed by a control circuit. 19. The debarking method of claim 18, further comprising the step of turning the chip feed conveyor off if no material is sensed at the chip feed conveyor for a period of time, wherein a chip feed conveyor delay to stop value corresponding to the period of time is stored in a look-up table and accessed by a control circuit. 20. The debarking method of claim 18, further comprising the step of varying the speed of the chip feed conveyor based on the quantity of material sensed in the chip feed conveyor. 21. A method for controlling a debarking process, comprising the method steps of: (a) sensing at an infeed conveyor at least one of the presence and quantity of material, and generating an infeed conveyor signal; (b) varying the speed of the infeed conveyor based on the infeed conveyor signal; (c) sensing at a debarking drum at least one of the presence and quantity of material, and generating a debarking drum signal; (d) varying the speed of rotation of the debarking drum based on the debarking drum signal; (e) sensing at a discharge conveyor at least one of the presence and quantity of material, and generating a discharge conveyor signal; and (f) varying the speed of the discharge conveyor based on the discharge conveyor signal; wherein a control value corresponding to each of the infeed conveyor signal, debarking drum signal, and discharge conveyor signal is stored in a look-up table and accessed by a control circuit to vary the speed of the infeed conveyor, debarking drum, and discharge conveyor, respectively. 22. The method of claim 21, further comprising the method steps of: (a) sensing at a chip feed conveyor at least one of the presence and quantity of material, and generating a chip feed conveyor signal; and (b) varying the speed of the chip feed conveyor based on the chip feed conveyor signal; wherein a control value corresponding to the chip feed conveyor signal is stored in a look-up table and accessed by a control circuit to vary the speed of the chip feed conveyor. 23. The method of claim 22, further comprising the steps of: (a) receiving a material status signal indicating one of one or more of the variety of material being processed and the time at which the processing is being performed; and (b) calculating which of a plurality of look-up tables to access for each of the infeed conveyor signal, debarking drum signal, discharge conveyor signal, and chip feed conveyor signal based upon the material status signal. | This application claims priority based on U.S. provisional patent application No. 60/508,195, filed on Oct. 2, 2003 and entitled “Automatic Fiber Yield System and Method,” which is incorporated herein by reference. BACKGROUND OF THE INVENTION The present invention relates to control systems for wood fiber processing machinery, and in particular to automatic controls for drum-based debarking machines that incorporate sensors and speed control mechanisms. Debarking systems that incorporate rotating drums are known in the art. An example of such a system is taught by U.S. Patent No. RE37,460 to Price et al., which is incorporated herein by reference. Such systems feature a large horizontal drum into which logs are inserted for debarking. The drum is fitted so as to rotate about its horizontal axis. As the drum rotates, the logs inserted within the drum rub against each other, thereby removing bark from the logs as they contact each other. The removal of bark is an essential step in the process of reducing logs to chips, which may ultimately be used in the manufacture of paper and other wood fiber products. Drum debarking may also be performed with respect to logs that are to be used for lumber. An elevated, curved hopper is generally positioned at one end of the debarking drum, and the groups of logs to be debarked are fed into the drum using a chain-type conveyor. An auxiliary feed roller may be positioned between the chain conveyor and the drum to aid in the manipulation of longer logs through the rotating drum. A discharge conveyor is positioned on the outlet end of the rotating drum to receive debarked logs. In applications such as the creation of chips for the manufacture of paper, the material may then be feed to a chip mill conveyor for further processing of the raw wood fibers. Conventional drum debarkers operate using simple manual controls. Before logs are to be fed into the debarker, the rotating drum and the chain conveyor are placed in the “on” position by the operator using a manual switch. In such systems, the conveyors and debarker drum are constantly in motion during operation. The speed of the conveyors, and the rate of rotation for the drum, is generally not variable. The conveyors and drum are not turned off until all of the logs and debris have moved through the system. Simple manual operation of the debarking system has a number of disadvantages. The optimal rate of rotation for the debarking drum is determined, in part, by the number of logs within the drum at any given time. If, for example, the rate of rotation is too great for the number of logs present, then usable wood fiber material will be stripped from the logs after all bark is removed. The wood fiber lost in this manner cannot feasibly be separated from the removed bark, and thus is discarded as waste. Likewise, if the rate of rotation is too slow, then logs will be moved from the debarker without complete debarking having taken place. Since incomplete debarking is unacceptable, current practice is to simply run the debarking drum at a speed that will ensure debarking for any expected number of logs within the debarking drum at any given time. The result is wasted wood fiber material that is removed from the logs when the number of logs in the debarking drum would favor a lower speed. The length of time that the logs remain in the debarking drum is also an important variable, which in a manual system is determined by the operator through visual inspection. If the operator leaves the logs in the drum for too long then material is wasted, but if the operator removes the logs too soon then they will have bark remaining and must be run through the debarking system a second time. Logs of varying quality and condition will require variances in the optimal debarking time. Wood variety and the season in which the debarking is performed are especially important factors in determining the optimal debarking time. Since logs of varying quality and condition will require different optimal debarking times, effective manual operation of a debarker requires considerable operator experience. Even with an experienced operator, however, the calculation of an optimal debarking time relies to some extent on guesswork. Training of a new operator requires a considerable amount of time since the new operator must obtain an intuitive feel for the nature of the logs in various conditions and in various seasons in order to operate a debarking system at acceptable efficiency. Another disadvantage of the standard manual mode of operation for a debarking system is excessive wear on equipment. The operation of conveyors and debarking drums at full speed with no wood fiber present in the system causes friction and excessive wear of the machine components. These components are designed to operate best when material is present, but in a practical setting it is impossible to maintain an even and steady flow of material at all times during operation. An attempt to remedy this problem by constantly turning conveyors and the rotating drum off and on would also cause excessive wear of the machine components, since start-up and shutdown also causes considerable wear on the machinery. Furthermore, it would be exceedingly difficult for a human operator to constantly monitor the various components of a debarking system simultaneously and switch them on and off in an optimal manner as material moves through the system. Such a task would likely require multiple human operators. The related art includes various attempts to develop automated control systems in the wood products industry. For example, U.S. Pat. No. 5,020,579 to Strong teaches an automatic feed control mechanism for a wood chipping machine. An infeed control circuit automatically adjusts infeed material capacity based on a load reading taken on the infeed conveyor. The control system automatically lifts a roller in the machine in order to clear jams, which are indicated by an infeed conveyor load reading that passes a certain pre-set value. Another such device is taught by U.S. Pat. No. 6,539,993 to Starr. The system separates single logs, and then reads the diameter and volume of the logs in order to optimize debarking. A ring-style debarker is utilized. An “image” of each log is then taken, which allows an optimization of the log cutting length to be determined. Each log is then cut to length and sorted into bins of similar-length logs. U.S. Pat. No. 6,546,979 to Jonkka teaches an automated method for controlling a drum-type debarker. This system utilizes information about both the weight of logs in the debarking drum and the rotational torque of the drum. This information is used to compute information concerning the average log density and top level of the log bunch tumbling within the drum. Alternatively, the drum weight information may be combined with optical sensing of drum filling degree in order to calculate average log density. Based on the information acquired in this manner, the system varies the speed of the drum rotation in an attempt to optimize the debarking operation. The infeed rate and discharge rate may also be varied to achieve the desired parameters. Jonkka teaches that reliance on the filling degree of the drum alone cannot produce satisfactory results in computing a proper debarking time. The Jonkaa method offers advantages over manual control systems, but also suffers from important disadvantages. The calculations involved in this control system require precise measurement of the weight of material in the debarking drum as well as torque information related to the rotation of the debarking drum. These measurements require sensitive instruments, such as strain-gauge sensors and shaft transducers, the installation of which would involve substantial re-working of any existing debarking drum equipment already constructed. They would also substantially increase the cost of producing a new debarking drum. These limitations of the related art and others are overcome by the present invention as described below. SUMMARY OF THE INVENTION The present invention is directed to an automatic control system for a debarking apparatus that is designed to maximize wood fiber yield. The system may comprise three principal components. The first component is one or more programmable logic controllers (PLCs) or other computational elements. The PLCs control the operation of the conveyors and the debarking drum, in particular controlling the times at which these components may start, stop, speed up, or slow down. The PLCs draw on data collected from look-up tables, preferably stored in an electronic or magnetic medium. These look-up tables include information pertaining to the speed and operational timing of conveyors and the debarker drum. No complex calculations in order to compute these numbers are thus required. The present invention accounts for variations in wood quality by the use of multiple sets of look-up tables. The different look-up tables may each reflect a number of factors that influence optimal system operation, such as the variety of wood and the season in which the wood is being milled. The third component is one or more sensors that read information concerning the wood present at various points within the system. These sensors are preferably ultrasonic sensors, and may be used to detect the presence and quantity of material in a given location within the system. Preferably there are four locations at which such sensors are present: the drum feed conveyor, the debarking drum, the discharge conveyor, and the chipper feed conveyor. Using information gathered from these sensors, the PLCs access data at particular rows within the various look-up tables, and based on the data found the PLCs control the movements of the system conveyors and debarking drum. The invention overcomes the limitations of the related art by achieving a near-optimum fiber yield system for chip mills and paper mills without the complexity of instrumentation required to perform calculations such as average density. Instead, empirical data pertaining to the load of wood being run is stored in look-up tables for simple and immediate access. All necessary information in order to perform the simple PLC calculations called for in the invention is available from the use of ultrasonic sensors, which can measure the quantity of material present at a given location at a given time. It is therefore an object of the present invention to provide for an automatic control system and method to optimize fiber yields in debarking systems. It is a further object of the present invention to provide for an automatic control system and method that does not rely on complex instrumentation or wood density calculations. It is also an object of the present invention to provide for an automatic control mechanism that may be easily retrofitted to existing debarking systems. It is also an object of the present invention to provide for an automatic control mechanism for debarking systems that simplifies operation of the debarking system. These and other features, objects and advantages of the present invention will become better understood from a consideration of the following detailed description of the preferred embodiments and appended claims in conjunction with the drawings as described following: DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 is a side elevational view of the major mechanical components for a debarking apparatus according to a preferred embodiment of the present invention. FIG. 2 is a diagram illustrating the control system components for a debarking apparatus according to a preferred embodiment of the present invention. FIG. 3 is an illustration of example data in a group of look-up tables according to a preferred embodiment of the present invention. FIG. 4 is a flow chart illustrating the computational logic for controlling the infeed conveyor of a debarking apparatus according to a preferred embodiment of the present invention. FIG. 5 is a flow chart illustrating the computational logic for controlling the debarking drum of a debarking apparatus according to a preferred embodiment of the present invention. FIG. 6 is a flow chart illustrating the computational logic for controlling the discharge conveyor of a debarking apparatus according to a preferred embodiment of the present invention. FIG. 7 is a flow chart illustrating the computational logic for controlling the chip feed conveyor of a debarking apparatus according to a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIGS. 1 and 2, a debarking apparatus and control system according to a preferred embodiment of the present invention may now be described. The apparatus includes an infeed conveyor (alternatively referred to as a “positive feed” conveyor) 10, a rotating debarking drum 12, a discharge conveyor 14, and a chip feed conveyor 16. Infeed conveyor 10 is used to direct logs toward debarking drum 12. In the preferred embodiment, infeed conveyor 10 may be a chain conveyor of conventional type. Infeed conveyor 10 is driven by drive motor 26. Drive motor 26 (and the other drive motors described herein) may be of a conventional electric or hydraulic type in alternative embodiments. Logs may be fed into infeed conveyor 10 by an overhead crane, a forklift-type loader, or other means (not shown), and are carried by infeed conveyor 10 into debarking drum 12. Debarking drum 12 is shaped as an open-ended cylinder, and is supported by a cradle of rollers 29 in horizontal fashion. Debarking drum 12 is driven by a variable speed motor 28, which causes it to rotate about its horizontal axis. The rotation of drum 12 causes logs fed into drum 12 from infeed conveyor 10 to rub against one another, and thereby results in the bark being removed from the logs as a result of the friction between the logs. Ideally, the logs are removed from debarking drum 12 just as all bark is removed so that the maximum amount of fiber will be retained in the logs for conversion to paper pulp or other desired wood fiber materials. Logs emerging from debarking drum 12 are fed onto discharge conveyor 14. Like infeed conveyor 10, discharge conveyor 14 may preferably be a chain conveyor of conventional type, and is driven by motor 30. Discharge conveyor 14 feeds the debarked logs onto chip feed conveyor 16, which is driven by drive motor 32. Chip feed conveyor 16, which may also be of a conventional chain-conveyor type, may then feed the logs into a chip mill for ultimate use in wood pulp or for other applications. Although chip feed conveyor 16 may be omitted from the invention, it is included in the preferred embodiment since it is traditional for chip mills to use this additional conveyor. Any waste material that may exit debarking drum 12 and thereby travel up discharge conveyor 14 may be dropped in the gap between discharge conveyor 14 and chip feed conveyor 16. The use of chip feed conveyor 16 thereby improves the quality of the chip material that will eventually be produced from the logs since only a trivial quantity of waste material will find its way to the end of chip feed conveyor 16 in conjunction with the logs. Ultrasonic sensors are positioned at key locations along the preferred embodiment of the invention, as depicted in FIG. 2. Infeed conveyor sensor 26 is positioned to sense material that is placed on infeed conveyor 10. Drum sensor 20 is positioned to sense material that is on infeed conveyor 10 just before entering debarking drum 12. Discharge conveyor sensor 22 is positioned to sense material that is at discharge conveyor 14, and chip feed conveyor sensor 24 is positioned to sense material that is at chip feed conveyor 16. In the preferred embodiment, discharge conveyor sensor 22 (as well as the other sensors described herein) are ultrasonic sensors model no. IRU-3135, manufactured by STI Automation of Logan, Utah. Other types of sensors could be used in alternative embodiments, including without limitation other models and brands of ultrasonic sensors as well as various types of optical sensors. The major components of the control system of the preferred embodiment may now be described with continued reference to FIG. 2. The signals from infeed conveyor sensor 18, debarking drum sensor 20, discharge conveyor sensor 22, and chip feed conveyor sensor 24 are fed as inputs to programmable logic controller (PLC) 34. PLCs are well-known devices for use in process control applications in industrial plants. They are commercially available in many varieties, options including the number of inputs and outputs, processing speed, and logic complexity. In the preferred embodiment, PLC 34 is one of either Allen Bradley SLC-5 or PLC-5 models, manufactured by Rockwell Automation of Milwaukee, Wis. The PLC programming software used in the preferred embodiment is RSLogix 500, also available from Rockwell Automation. Many other models of PLCs and various types of programming software could be substituted in alternative embodiments. PLC 34 generates output signals that are fed to infeed conveyor motor 26, debarker drum motor 28, discharge conveyor motor 30, and chip feed conveyor motor 32. These signals are used to stop, start, and vary the speed of these motors, and thereby control the operation of infeed conveyor 10, debarking drum 12, discharge conveyor 14, and chip feed conveyor 16. Specifically, according to the preferred embodiment infeed conveyor 10 may be turned on and off by control signals sent to infeed conveyor motor 26; debarker drum 12 may be set to high-speed rotation, low-speed rotation, or turned off by control signals sent to debarker drum motor 28; discharge conveyor 14 may be set to high-speed travel, low-speed travel, or turned off by control signals sent to discharge conveyor motor 30; and chip feed conveyor 16 may be set to high-speed travel, low-speed travel, or turned off by control signals sent to chip feed conveyor motor 32. PLC 34 is also in communication with look-up tables 36. Look-up tables are logical constructs intended to store numbers in designated locations for easy look-up by PLC 34 when needed. Look-up tables 36 may be implemented in any electronic, magnetic, optical, or other computer-readable media. These tables may be read into a random access memory area of PLC 34 in order to be utilized. FIG. 3 shows the logical arrangement of three exemplary tables 40 according to a preferred embodiment of the invention. (It should be noted that the exemplary values shown in tables 40 do not necessarily represent optimal values for any particular wood variety or season.) The values in the tables 40 are used to control various parameters of the debarking system as will be explained in greater detail below. While three exemplary tables 40 are shown in FIG. 3, any number of tables 36 may be implemented in the preferred embodiment of the invention, according to the needs of the system. This will depend upon may factors; for example, the number of wood varieties processed at a particular mill. Personal computer 38 is used to input data to PLC 34, including the creation and deletion of tables 36, and the review and editing of the various values in tables 36. Referring now to FIG. 4, the computational logic implemented in PLC 34 to control infeed conveyor 10 according to a preferred embodiment of the invention may now be described. At input block 50, information from infeed conveyor sensor 18 is fed to decision block 52. This information will be in the form of a bed depth of material on infeed conveyor 10, preferably measured in inches. At decision block 52, the amount of material detected at infeed conveyor sensor 18 is compared to the “PFC infeed sensor depth” value at block 53, which is stored in the appropriate look-up table 36. If the quantity of material exceeds the value found in look-up table 36, then processing continues to decision block 54. At decision block 54, if infeed conveyor 10 is already on, then processing returns to decision block 52. If infeed conveyor 10 is currently off, then processing moves to process block 56. At process block 56, the infeed conveyor is turned on after a delay as designated in the “PFC infeed delay” value at block 57. This value is the number of seconds of delay after material is detected that infeed conveyor is to be turned on, and is stored in the appropriate look-up table 36. After completion of the process at process block 56, processing returns to decision block 52. If a sufficient quantity of material is not detected at decision block 52, then processing moves to decision block 61. At decision block 61, the logic of PLC 34 inquires whether infeed conveyor 10 is currently stopped. If the answer is yes, then processing returns to decision block 52. If the answer is no, then processing continues to decision block 58. At decision block 58, the delay since the lack of material was first detected is compared to the “PFC delay to stop” value at block 59. Again, the “PFC delay to stop” value is stored in the appropriate table 36. If the delay time before stopping has not been reached, then processing is returned to decision block 52. If the delay time before stopping has been reached, then the conveyor is turned off at process block 60, and processing returns to decision block 52. Referring now to FIG. 5, the computational logic implemented in PLC 34 to control debarking drum 12 according to a preferred embodiment of the invention may now be described. At input block 62, information from debarking drum sensor 20 is fed to decision block 64. As was the case for infeed conveyor sensor 18, this information will be in the form of a bed depth of material, preferably measured in inches, but in this case the measurement will be of material that is just approaching the entrance to debarking drum 12. At decision block 64, the amount of material detected that is about to enter debarking drum 12 is compared to the “PFC sensor depth” value at block 65, which is stored in the appropriate look-up table 36. If the quantity of material exceeds the value found in look-up table 36, then processing continues to decision block 68. At decision block 68, if debarking drum 12 is already on and running at high speed, then processing returns to decision block 64. If debarking drum 12 is currently off or running at low speed, then processing moves to process block 70. At process block 70, debarking drum 12 is turned to a high speed setting, the rotation per minute (RPM) value of which is designated in the “Drum fast speed” value at block 71. This value is stored in and is retrieved from the appropriate look-up table 36 by PLC 34. After completion of the process at process block 70, processing returns to decision block 64. If a sufficient quantity of material is not detected at decision block 64, then processing moves to decision block 80. At decision block 80, the logic of PLC 34 inquires whether debarking drum 12 is currently stopped. If the answer is yes, then processing returns to decision block 64. If the answer is no, then processing continues to decision block 66. At decision block 66, the logic of PLC 34 inquires whether debarking drum 12 is currently running at its high-speed setting. If so, then processing moves to decision block 72. Here the logic of PLC 34 compares the delay since the lack of material was first detected with the “Drum delay to slow” value at block 73, which is stored in the appropriate table 36. If the delay time before returning to low speed has not been reached, then processing is returned to decision block 64. If the delay time before returning to low speed has been reached, then debarking drum 12 is turned to its low-speed setting at process block 74, and processing returns to decision block 64. If at decision block 66 it is determined that debarking drum 12 is not currently running at its high-speed setting, then processing moves to decision block 76. At decision block 76, the logic of PLC 34 compares the delay since the lack of material was first detected to the “Drum delay to stop” value at block 77. Again, the “Drum delay to stop” value is stored in the appropriate table 36. If the delay time before stopping has not been reached, then processing is returned to decision block 64. If the delay time before stopping has been reached, then the conveyor is turned off at process block 78, and processing returns to decision block 64. Referring now to FIG. 6, the computational logic implemented in PLC 34 to control discharge conveyor 14 according to a preferred embodiment of the present invention may now be described. Before automatic control begins, the operator generally sets discharge conveyor 14 to run at its low-speed setting using manual controls. Automatic processing them begins at input block 82, where information from discharge sensor 22 is fed to decision block 84. As was the case for infeed conveyor sensor 18 and debarker drum sensor 20, this information will be in the form of a bed depth of material, preferably measured in inches, but in this case the measurement will be of material that is just entering discharge conveyor 14. At decision block 84, the amount of material detected that is entering discharge conveyor 14 is compared to the “DDC sensor depth” value at block 85, which is stored in the appropriate look-up table 36. If the quantity of material exceeds the value found in look-up table 36, then processing continues to decision block 86. At decision block 86, if discharge conveyor 14 is already on and running at high speed, then processing returns to decision block 84. If discharge conveyor 14 is currently off or running at low speed, then processing moves to process block 88. At process block 88, discharge conveyor 14 is turned to a high-speed setting, the feet per minute value of which is designated in the “DDC fast speed” value at block 89. This value is stored in and is retrieved from the appropriate look-up table 36 by PLC 34. After completion of the process at process block 88, processing returns to decision block 84. If a sufficient quantity of material is not detected at decision block 84, then processing moves to decision block 90. At decision block 90, the logic of PLC 34 inquires whether discharge conveyor 14 is currently stopped. If the answer is yes, then processing returns to decision block 84. If the answer is no, then processing continues to decision block 92. At decision block 92, the logic of PLC 34 inquires whether discharge conveyor 14 is currently running at its high-speed setting. If so, then processing moves to decision block 98. Here the logic of PLC 34 compares the delay since the lack of material was first detected with the “DDC delay to slow” value at block 99, which is stored in the appropriate table 36. If the delay time before returning to low speed has not been reached, then processing is returned to decision block 84. If the delay time before returning to low speed has been reached, then discharge conveyor 14 is turned to its low-speed setting at process block 100, and processing returns to decision block 84. If at decision block 92 it is determined that discharge conveyor 14 is not currently running at its high-speed setting, then processing moves to decision block 94. At decision block 94, the logic of PLC 34 compares the delay since the lack of material was first detected to the “DDC delay to stop” value at block 95. Again, the “DDC delay to stop” value is stored in the appropriate table 36. If the delay time before stopping has not been reached, then processing is returned to decision block 84. If the delay time before stopping has been reached, then the conveyor is turned off at process block 96, and processing returns to decision block 84. Referring now to FIG. 7, the computational logic implemented in PLC 34 to control chip feed conveyor 16 according to a preferred embodiment of the present invention may now be described. Before automatic control begins, the operator generally sets chip feed conveyor 16 to run at its low-speed setting using manual controls. Automatic processing them begins at input block 102, where information from chip feed sensor 24 is fed to decision block 104. As was the case for infeed conveyor sensor 18, debarker drum sensor 20, and discharge conveyor sensor 22, this information will be in the form of a bed depth of material, preferably measured in inches, but in this case the measurement will be of material that is just entering chip feed conveyor 16. At decision block 104, the amount of material detected that is entering chip feed conveyor 16 is compared to the “CFC sensor depth” value at block 105, which is stored in the appropriate look-up table 36. If the quantity of material exceeds the value found in look-up table 36, then processing continues to decision block 106. At decision block 106, if chip feed conveyor 16 is already on and running at high speed, then processing returns to decision block 104. If chip feed conveyor 16 is currently off or running at low speed, then processing moves to process block 108. At process block 108, chip feed conveyor 16 is turned to a high-speed setting, the feet per minute value of which is designated in the “CFC fast speed” value at block 109. This value is stored in and is retrieved from the appropriate look-up table 36 by PLC 34. After completion of the process at process block 108, processing returns to decision block 104. If a sufficient quantity of material is not detected at decision block 104, then processing moves to decision block 110. At decision block 110, the logic of PLC 34 inquires whether chip feed conveyor 16 is currently stopped. If the answer is yes, then processing returns to decision block 104. If the answer is no, then processing continues to decision block 102. At decision block 102, the logic of PLC 34 inquires whether chip feed conveyor 16 is currently running at its high-speed setting. If so, then processing moves to decision block 118. Here the logic of PLC 34 compares the delay since the lack of material was first detected with the “CFC delay to slow” value at block 119, which is stored in the appropriate table 36. If the delay time before returning to low speed has not been reached, then processing is returned to decision block 104. If the delay time before returning to low speed has been reached, then chip feed conveyor 16 is turned to its low-speed setting at process block 120, and processing returns to decision block 104. If at decision block 112 it is determined that chip feed conveyor 16 is not currently running at its high-speed setting, then processing moves to decision block 114. At decision block 114, the logic of PLC 34 compares the delay since the lack of material was first detected to the “CFC delay to stop” value at block 115. Again, the “CFC delay to stop” value is stored in the appropriate table 36. If the delay time before stopping has not been reached, then processing is returned to decision block 104. If the delay time before stopping has been reached, then the conveyor is turned off at process block 116, and processing returns to decision block 104. Each of the delay times, speed settings, and material level settings associated with the operation of each component of the debarking system is stored in an appropriate table 36. Any number of tables 36 may be used in the preferred embodiment. Each table corresponds to a certain collection of settings that may be based on variables associated with the processing time of the material that is being run by the debarking apparatus. Such variables include, but are not necessarily limited to, the variety of the wood being processed and the season in which the wood is being processed. A different table may be assigned for operation of the debarking apparatus at any given time based upon these factors. The proper table to be used for a particular operating session may be chosen by the operator through computer 38. The values in each table 36 are determined empirically from actual operation of the debarking apparatus and from the programmer's experience with such systems. Once a particular table 36 is chosen, the system may be run without change of the chosen table 36 until a change in wood quality (such as wood variety or season) is determined to exist. It should be noted that in the preferred embodiment, all of the controls for infeed conveyor motor 26, debarker drum motor 28, discharge conveyor motor 30, and chip feed conveyor 32 may be operated in a manual or override mode as necessary. As is evident from the above description of the control circuitry, the invention allows the debarking of material to be fed to a chip mill or other similar application to generally proceed with little human intervention. The invention saves energy and reduces component wear by slowing down or stopping those components that are not in use at any given time. For example, infeed conveyor 10 will be shut down after a period of time without use; debarker drum 12 will be slowed down after a period of time without use, and will be brought to a stop after an extended period of time without use; discharge conveyor 14 will be slowed down after a period of time without use, and will be brought to a stop after an extended period of time without use; and chip feed conveyor 16 will be slowed down after a period of time without use, and will be brought to a stop after an extended period of time without use. It should be noted that while the preferred embodiment has been described, the invention also comprises a number of alternative embodiments. The debarking apparatus components with variable-speed drive systems, which could be any of the components as desired, could be controlled with any number of speed settings rather than the two of the preferred embodiment. Likewise, the speed of these components could be made continuously variable dependent upon a calculation based upon the quantity of material present. The present invention has been described with reference to certain preferred and alternative embodiments that are intended to be exemplary only and not limiting to the full scope of the present invention as set forth in the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>The present invention relates to control systems for wood fiber processing machinery, and in particular to automatic controls for drum-based debarking machines that incorporate sensors and speed control mechanisms. Debarking systems that incorporate rotating drums are known in the art. An example of such a system is taught by U.S. Patent No. RE37,460 to Price et al., which is incorporated herein by reference. Such systems feature a large horizontal drum into which logs are inserted for debarking. The drum is fitted so as to rotate about its horizontal axis. As the drum rotates, the logs inserted within the drum rub against each other, thereby removing bark from the logs as they contact each other. The removal of bark is an essential step in the process of reducing logs to chips, which may ultimately be used in the manufacture of paper and other wood fiber products. Drum debarking may also be performed with respect to logs that are to be used for lumber. An elevated, curved hopper is generally positioned at one end of the debarking drum, and the groups of logs to be debarked are fed into the drum using a chain-type conveyor. An auxiliary feed roller may be positioned between the chain conveyor and the drum to aid in the manipulation of longer logs through the rotating drum. A discharge conveyor is positioned on the outlet end of the rotating drum to receive debarked logs. In applications such as the creation of chips for the manufacture of paper, the material may then be feed to a chip mill conveyor for further processing of the raw wood fibers. Conventional drum debarkers operate using simple manual controls. Before logs are to be fed into the debarker, the rotating drum and the chain conveyor are placed in the “on” position by the operator using a manual switch. In such systems, the conveyors and debarker drum are constantly in motion during operation. The speed of the conveyors, and the rate of rotation for the drum, is generally not variable. The conveyors and drum are not turned off until all of the logs and debris have moved through the system. Simple manual operation of the debarking system has a number of disadvantages. The optimal rate of rotation for the debarking drum is determined, in part, by the number of logs within the drum at any given time. If, for example, the rate of rotation is too great for the number of logs present, then usable wood fiber material will be stripped from the logs after all bark is removed. The wood fiber lost in this manner cannot feasibly be separated from the removed bark, and thus is discarded as waste. Likewise, if the rate of rotation is too slow, then logs will be moved from the debarker without complete debarking having taken place. Since incomplete debarking is unacceptable, current practice is to simply run the debarking drum at a speed that will ensure debarking for any expected number of logs within the debarking drum at any given time. The result is wasted wood fiber material that is removed from the logs when the number of logs in the debarking drum would favor a lower speed. The length of time that the logs remain in the debarking drum is also an important variable, which in a manual system is determined by the operator through visual inspection. If the operator leaves the logs in the drum for too long then material is wasted, but if the operator removes the logs too soon then they will have bark remaining and must be run through the debarking system a second time. Logs of varying quality and condition will require variances in the optimal debarking time. Wood variety and the season in which the debarking is performed are especially important factors in determining the optimal debarking time. Since logs of varying quality and condition will require different optimal debarking times, effective manual operation of a debarker requires considerable operator experience. Even with an experienced operator, however, the calculation of an optimal debarking time relies to some extent on guesswork. Training of a new operator requires a considerable amount of time since the new operator must obtain an intuitive feel for the nature of the logs in various conditions and in various seasons in order to operate a debarking system at acceptable efficiency. Another disadvantage of the standard manual mode of operation for a debarking system is excessive wear on equipment. The operation of conveyors and debarking drums at full speed with no wood fiber present in the system causes friction and excessive wear of the machine components. These components are designed to operate best when material is present, but in a practical setting it is impossible to maintain an even and steady flow of material at all times during operation. An attempt to remedy this problem by constantly turning conveyors and the rotating drum off and on would also cause excessive wear of the machine components, since start-up and shutdown also causes considerable wear on the machinery. Furthermore, it would be exceedingly difficult for a human operator to constantly monitor the various components of a debarking system simultaneously and switch them on and off in an optimal manner as material moves through the system. Such a task would likely require multiple human operators. The related art includes various attempts to develop automated control systems in the wood products industry. For example, U.S. Pat. No. 5,020,579 to Strong teaches an automatic feed control mechanism for a wood chipping machine. An infeed control circuit automatically adjusts infeed material capacity based on a load reading taken on the infeed conveyor. The control system automatically lifts a roller in the machine in order to clear jams, which are indicated by an infeed conveyor load reading that passes a certain pre-set value. Another such device is taught by U.S. Pat. No. 6,539,993 to Starr. The system separates single logs, and then reads the diameter and volume of the logs in order to optimize debarking. A ring-style debarker is utilized. An “image” of each log is then taken, which allows an optimization of the log cutting length to be determined. Each log is then cut to length and sorted into bins of similar-length logs. U.S. Pat. No. 6,546,979 to Jonkka teaches an automated method for controlling a drum-type debarker. This system utilizes information about both the weight of logs in the debarking drum and the rotational torque of the drum. This information is used to compute information concerning the average log density and top level of the log bunch tumbling within the drum. Alternatively, the drum weight information may be combined with optical sensing of drum filling degree in order to calculate average log density. Based on the information acquired in this manner, the system varies the speed of the drum rotation in an attempt to optimize the debarking operation. The infeed rate and discharge rate may also be varied to achieve the desired parameters. Jonkka teaches that reliance on the filling degree of the drum alone cannot produce satisfactory results in computing a proper debarking time. The Jonkaa method offers advantages over manual control systems, but also suffers from important disadvantages. The calculations involved in this control system require precise measurement of the weight of material in the debarking drum as well as torque information related to the rotation of the debarking drum. These measurements require sensitive instruments, such as strain-gauge sensors and shaft transducers, the installation of which would involve substantial re-working of any existing debarking drum equipment already constructed. They would also substantially increase the cost of producing a new debarking drum. These limitations of the related art and others are overcome by the present invention as described below. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention is directed to an automatic control system for a debarking apparatus that is designed to maximize wood fiber yield. The system may comprise three principal components. The first component is one or more programmable logic controllers (PLCs) or other computational elements. The PLCs control the operation of the conveyors and the debarking drum, in particular controlling the times at which these components may start, stop, speed up, or slow down. The PLCs draw on data collected from look-up tables, preferably stored in an electronic or magnetic medium. These look-up tables include information pertaining to the speed and operational timing of conveyors and the debarker drum. No complex calculations in order to compute these numbers are thus required. The present invention accounts for variations in wood quality by the use of multiple sets of look-up tables. The different look-up tables may each reflect a number of factors that influence optimal system operation, such as the variety of wood and the season in which the wood is being milled. The third component is one or more sensors that read information concerning the wood present at various points within the system. These sensors are preferably ultrasonic sensors, and may be used to detect the presence and quantity of material in a given location within the system. Preferably there are four locations at which such sensors are present: the drum feed conveyor, the debarking drum, the discharge conveyor, and the chipper feed conveyor. Using information gathered from these sensors, the PLCs access data at particular rows within the various look-up tables, and based on the data found the PLCs control the movements of the system conveyors and debarking drum. The invention overcomes the limitations of the related art by achieving a near-optimum fiber yield system for chip mills and paper mills without the complexity of instrumentation required to perform calculations such as average density. Instead, empirical data pertaining to the load of wood being run is stored in look-up tables for simple and immediate access. All necessary information in order to perform the simple PLC calculations called for in the invention is available from the use of ultrasonic sensors, which can measure the quantity of material present at a given location at a given time. It is therefore an object of the present invention to provide for an automatic control system and method to optimize fiber yields in debarking systems. It is a further object of the present invention to provide for an automatic control system and method that does not rely on complex instrumentation or wood density calculations. It is also an object of the present invention to provide for an automatic control mechanism that may be easily retrofitted to existing debarking systems. It is also an object of the present invention to provide for an automatic control mechanism for debarking systems that simplifies operation of the debarking system. These and other features, objects and advantages of the present invention will become better understood from a consideration of the following detailed description of the preferred embodiments and appended claims in conjunction with the drawings as described following: | 20040420 | 20081007 | 20050407 | 88569.0 | 0 | SELF, SHELLEY M | AUTOMATIC FIBER YIELD SYSTEM AND METHOD | SMALL | 0 | ACCEPTED | 2,004 |
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10,828,110 | ACCEPTED | Multi-elevation singulation of device laminates in wafer scale and substrate processing | Wafer scale and substrate processing device singulation methods, and devices made by the methods, for singulation of discrete devices from a processed wafer or laminated structures, involves formation of separation scribes or saw cuts at multiple elevations in intersecting scribe streets or lines so that a separation cut in one direction is at a different depth than a separation cut in a different and intersecting direction. Separation or fracture of the wafer or laminated structure along one of the separation cuts does not transfer to the separation line of the intersecting separation cut due to the difference in depth of the intersecting cuts or scribes, and due to the difference in elevation of the bottom surfaces of the cuts or scribes within the scribe streets, resulting in cleaner edges on the separated devices. | 1. A method of manufacturing a plurality of devices from a structure having scribe streets for receiving cuts by which the structure is separated into a plurality of devices, the method comprising the steps of: forming a first cut in a first scribe street on the structure to a first depth; forming a second cut in a second scribe street on the structure to a second depth; separating the structure generally along the first cut, and further separating the structure generally along the second cut into a plurality of devices. 2. The method of claim 1 wherein the first depth of the fist cut is greater than the second depth of the second cut. 3. The method of claim 1 wherein the second depth of the second cut is greater than the first depth of the first cut. 4. The method of claim 1 wherein multiple first cuts are made in multiple first scribe streets which are generally parallel. 5. The method of claim 1 wherein multiple second cuts are made in multiple second scribe streets which are generally parallel and generally perpendicular the first scribe street. 6. The method of claim 1 wherein the structure is in the form of a laminate with multiple layers and the fist cut is made in a top layer of the laminate. 7. The method of claim 1 wherein the structure is in the form of a laminate with multiple layers and the second cut is made in a top layer of the laminate. 8. The method of claim 1 wherein the structure is in the form of a laminate with multiple layers and the first cut is made substantially through a top layer of the laminate. 9. The method of claim 1 wherein the structure is in the form of a laminate with multiple layers and the second cut is made substantially through a top layer of the laminate. 10. The method of claim 1 wherein the structure is in the form of a laminate with multiple layers and the structure is separated through each of the layers of the laminate generally along the first and second cuts. 11. A processed structure having multiple devices formed thereon and arranged in a matrix with intersecting first and second scribe streets between the devices, first cuts in the first scribe streets to a first depth, and second cuts in the second scribe streets to a second depth. 12. The processed structure of claim 1 wherein the first cuts are relatively deeper than the second cuts. 13. The processed structure of claim 11 wherein the second cuts are relatively deeper than the first cuts. 14. The processed structure of claim 11 in combination with at least one laminated layer, and wherein the first and second cuts are in at least one of the laminated layers. 15. The processed structure of claim 11 wherein the first and second scribe streets are perpendicular. 16. The processed structure of claim 11 wherein the first and second cuts are saw cuts. 17. The processed structure of claim 11 wherein the first and second cuts are scribes. 18. The processed structure of claim 11 wherein intersections of the first and second strets have a cut depth which is the same as the deepest of the first or second cuts. 19. A laminated structure having multiple devices and a plurality of intersecting scribe streets between the devices; a plurality of separation cuts made in the scribe streets for separation of the devices along the separation cuts, at least one of the separation cuts having a depth dimension different than a depth dimension of another of the separation cuts in the laminated structure. 20. The laminated structure of claim 19 wherein the laminated structure includes a silicon layer, a reflective layer, and a circuitry layer. 21. The laminated structure of claim 20 wherein the circuitry layer includes circuitry for devices operative to control a liquid crystal cell. 22. The laminated structure of claim 19 wherein the separation cuts are saw cuts. 23. The laminated structure of claim 19 wherein the separation cuts are scribes. 24. A liquid crystal device made from a die separated from a processed wafer which includes a substrate layer and at least one circuitry layer, the die being separated from the wafer along a cut on a first side of the die and along a cut on a second side of the die, wherein the cut on the first side of the die has a depth in the wafer different than a depth of the cut on the second side of the die. 25. The liquid crystal device of claim 24 wherein the die is separated from the wafer along cuts on four sides of the die, and wherein at least one of the cuts on one of the four sides of the device has a depth which differs from the depth or depths of the other cuts. 26. The liquid crystal device of claim 24 wherein the die is separated from the wafer first along cuts which are deepest in the die. | FIELD OF THE INVENTION The present invention pertains to wafer scale and substrate processing and fabrication of electronic devices, and more particularly to singulation of discrete die or chip components from processed wafers or substrates or other structures of glass, silicon or other materials or laminated layers of materials. BACKGROUND OF THE INVENTION Wafer scale processing of semiconductor materials or laminates which include semiconductor material require singulation of discrete components or chips or dies by saw separation of the wafer. The chips are demarcated by scribe lines in the form of alleys which contain no circuitry or bond pads, where mechanical separation by sawing can be performed without damage to the circuitry on the dies. There are many challenges and risks associated with saw separation of device dies from wafers, including fragility of the dies and the need for cooling water, de-ionization agents, debris contamination and the possibility of partial or total damage of the wafer. Therefore, careful process control of saw scribe separation is required. Improvements to automated wafer singulation saw equipment has helped in these respects, as described for example in U.S. Pat. Nos. 5,059,899; 6,150,240 and 6,568,384, but have not adequately addressed all of these factors and the special challenges presented by laminated wafer dies. Scaled production of laminated devices, such as glass-on-silicon and glass-on-glass as used for example in liquid-crystal-on-silicon (LCoS) and reflective LCoS devices, requires clean saw separation of all of the layers of the laminate. Differences in material properties of the layers can result in rough or flared edges in one or more layers of the laminate. Non-square edges cause problems when aligning these types of devices with one another or to other mechanical edges. It would be desirable for the singulation process to result in separate laminate dies with optimally smooth edges for subsequent processing. SUMMARY OF THE INVENTION The invention provides an improved method and process for separation of laminate structures, included laminates of processed devices such as wafer-scale processed electronic devices, silicon or other semiconductor devices. In accordance with one general aspect of the invention, there is provided a method of manufacturing a plurality of devices from a wafer having scribe streets for receiving cuts by which the wafer is separated into a plurality of devices, including the steps of forming a first cut in a first scribe street to a first depth; forming a second cut in a second scribe street to a second depth; separating the wafer generally along the first cut, and further separating the wafer generally along the second cut into a plurality of devices. In a preferred embodiment of the invention, a first cut which is formed in the wafer is of a shallower depth relative to a second cut formed in the wafer. Also in a preferred embodiment of the invention, individual devices are separated from the wafer first by separation along first or second cuts which are relatively deeper than remaining first or second cuts. In accordance other embodiments and aspects of the invention, there is described a processed wafer with multiple devices formed thereon and arranged in a matrix with intersecting first and second scribe streets between the devices, with first cuts in the first scribe streets to a first depth, and second cuts in the second scribe streets to a second depth. And a laminated structure with multiple devices and a plurality of intersecting scribe streets between the devices; a plurality of separation cuts made in the scribe streets for separation of the devices along the separation cuts, at least one of the separation cuts having a depth dimension different than a depth dimension of another of the separation cuts in the laminated structure. These and other aspects and embodiments of the invention are described herein in detail with reference to the accompanying Drawings. DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view of a laminated processed wafer for singulation in accordance with the present invention; FIG. 2 is a perspective view of a laminated structure cut for singulation in accordance with the present invention; FIG. 3 is an elevation in the direction of the arrows 3-3 in FIG. 1 of a laminated structure cut for singulation in accordance with the present invention; FIG. 4 is an elevation in the direction of the arrows 4-4 in FIG. 1 of a laminated structure cut for singulation in accordance with the present invention. DETAILED DESCRIPTION OF PREFERRED AND ALTERNATE EMBODIMENTS As shown in FIG. 1, a typical processed wafer 100 contains multiple devices or dies 101, separated by scribe streets or lines 201 and 202 which are most commonly made in the orthogonal arrangement shown, but which may be in any pattern, and which may cross at multiple intersections 203 as shown. The processed wafer may be one of several layers of a laminate 1000, which includes a first or top layer 1001, one or more intermediate layers 1002, 1003, and one or more bottom or substrate layers 1004. Any of the layers of the laminate 1000 can be of any material known in the art, such as a layer of any semiconductor material, insulating layers, active layers, doped layers, reflective layers and structural or adhesive layers. Also, additional layers may be added to the laminate structure before or after the described singulation process. As used herein, the terms “wafer”, “laminate”, “laminate structure” and “structure” refer to any type or combination of materials in generally planar form and on or in which devices—such as any type of liquid crystal devices—are formed, and in which cuts or scribes are made to separate devices from the material. The laminate structure provides the processing advantage of allowing partial depth cuts in the scribe streets through the cross-section of the laminate. The present invention exploits this physical characteristic of a laminate structure by making a first separation cut 2011 in a first scribe line or scribe line direction, such as in one or more of scribe lines 201, to a first depth as shown in FIGS. 2 and 3. Cut 2011 may be to a depth, for example, which extends substantially through the top layer 1001 or closely proximate to an interface between the top layer 1001 and the immediate underlying intermediate layer, or completely through the top layer 1001 and into the immediately underlying layer or layers. The first cut 2011 is preferably to the least extent into the cross-section of the laminate 1000, but conversely can be the deepest of cuts in the separation process. Once the desired number of cuts 2011 are made in the aligned and common directions of scribe lines 201, a second cut or series of cuts 2021 are made within the scribe lines 202 which intersect scribe lines 201, and preferably at a depth which differs from the depth of cuts 2011. In the preferred process wherein cuts 2011 are formed first and to the least extent into the laminate cross-section, cuts 2021 are made second to a greater extent, i.e., deeper, than cuts 2011. Thus, as shown in FIG. 2, cuts 2011 do not touch the bottom or trough of cuts 2021 at the intersections 203. The invention however is not limited to the relative orientation, order or depths of the cuts 2011, 2021. For example, cuts 2011 can be made shallower than cuts 2021, or the shallow cuts made prior to formation of the relatively deeper cuts. With the laminate 1000 thus scribed or cut to multiple depths in intersecting lines, it is ready for singulation of the dies as separated by the cuts. Preferably, the laminate 1000 is separated or broken along the deeper of the cuts first, which allows the break to propagate along the trough of the deepest cut without interference by the intersecting but shallower cuts. Because the break occurs in a layer or layers of the laminate 1000 at the bottom trough of the deepest cut, the break does not see the intersecting shallower cuts and therefore stays linear and within the parameters of the deepest cut. With the laminate 1000 thus separated into strips along one linear dimension of the deepest cuts, 2011 or 2021, it can then be subsequently separated into individual dies by separation along the relatively shallower cuts which are transverse to the length of the strips. In the illustrated example, the laminate 1000 is first separated along cuts 2021, and then separated along cuts 2011 into individual dies. The method of singulation of a wafer into separate dies thus involves the steps of forming one or more scribes or saw cuts in a first direction to a first depth; forming one or more scribes or saw cuts in a second direction to a second depth; separating the wafer along the first or second scribes or saw cuts, and further separating the wafer along the first or second scribes or saw cuts. Preferably, the wafer is separated first along the deepest of the scribes or saw cuts. Because the secondary relatively shallower cuts are no longer intersected by any cuts, the risk of errant separation or irregular fracture between the dies is greatly reduced. With the resulting cleaner separation and demarcation of the die edges, the dies are in better condition for subsequent handling, processing and combining with other components. Because the invention relies in part upon the relative depths of intersecting scribes or saw cuts, the invention is not limited to the physical manner in which the scribes or saw cuts are formed in the wafer or other laminated structure. | <SOH> BACKGROUND OF THE INVENTION <EOH>Wafer scale processing of semiconductor materials or laminates which include semiconductor material require singulation of discrete components or chips or dies by saw separation of the wafer. The chips are demarcated by scribe lines in the form of alleys which contain no circuitry or bond pads, where mechanical separation by sawing can be performed without damage to the circuitry on the dies. There are many challenges and risks associated with saw separation of device dies from wafers, including fragility of the dies and the need for cooling water, de-ionization agents, debris contamination and the possibility of partial or total damage of the wafer. Therefore, careful process control of saw scribe separation is required. Improvements to automated wafer singulation saw equipment has helped in these respects, as described for example in U.S. Pat. Nos. 5,059,899; 6,150,240 and 6,568,384, but have not adequately addressed all of these factors and the special challenges presented by laminated wafer dies. Scaled production of laminated devices, such as glass-on-silicon and glass-on-glass as used for example in liquid-crystal-on-silicon (LCoS) and reflective LCoS devices, requires clean saw separation of all of the layers of the laminate. Differences in material properties of the layers can result in rough or flared edges in one or more layers of the laminate. Non-square edges cause problems when aligning these types of devices with one another or to other mechanical edges. It would be desirable for the singulation process to result in separate laminate dies with optimally smooth edges for subsequent processing. | <SOH> SUMMARY OF THE INVENTION <EOH>The invention provides an improved method and process for separation of laminate structures, included laminates of processed devices such as wafer-scale processed electronic devices, silicon or other semiconductor devices. In accordance with one general aspect of the invention, there is provided a method of manufacturing a plurality of devices from a wafer having scribe streets for receiving cuts by which the wafer is separated into a plurality of devices, including the steps of forming a first cut in a first scribe street to a first depth; forming a second cut in a second scribe street to a second depth; separating the wafer generally along the first cut, and further separating the wafer generally along the second cut into a plurality of devices. In a preferred embodiment of the invention, a first cut which is formed in the wafer is of a shallower depth relative to a second cut formed in the wafer. Also in a preferred embodiment of the invention, individual devices are separated from the wafer first by separation along first or second cuts which are relatively deeper than remaining first or second cuts. In accordance other embodiments and aspects of the invention, there is described a processed wafer with multiple devices formed thereon and arranged in a matrix with intersecting first and second scribe streets between the devices, with first cuts in the first scribe streets to a first depth, and second cuts in the second scribe streets to a second depth. And a laminated structure with multiple devices and a plurality of intersecting scribe streets between the devices; a plurality of separation cuts made in the scribe streets for separation of the devices along the separation cuts, at least one of the separation cuts having a depth dimension different than a depth dimension of another of the separation cuts in the laminated structure. These and other aspects and embodiments of the invention are described herein in detail with reference to the accompanying Drawings. | 20040419 | 20080122 | 20051020 | 75904.0 | 0 | LEE, CALVIN | MULTI-ELEVATION SINGULATION OF DEVICE LAMINATES IN WAFER SCALE AND SUBSTRATE PROCESSING | SMALL | 0 | ACCEPTED | 2,004 |
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10,828,138 | ACCEPTED | Component rejection station | The present invention features a method and apparatus wherein a component in a component placement machine is rejected during the placement cycle and subsequently retained in a component rejection station. A component is imaged and the image processed using an automated vision system. The image processing determines whether the component is placeable based upon a comparison of the component image to preprogrammed mechanical parameters for the component. A non-placeable component is rejected into a reject station with means to retain the component. Because a component can not escape the reject station, there is no degradation of the placement machine performance. | 1. A method for rejecting a component from a pick/place head in a component placement machine, the steps comprising: providing a component placement machine comprising a housing adapted for movement along an X and a Y axis above a printed circuit board and having a frame attached thereto, said frame having a one or more pick/place heads disposed thereupon; providing a vision system comprising a camera accessible to said one or more pick/place heads; picking a component from a supply of components using at least one of said one or more of pick/place heads; capturing an image of said picked component, and processing said captured image to determine whether said picked component is placeable or non-placeable; providing a reject station adapted to receive a component; adapting said reject station with means to reduce the force upon which said component impacts said reject station; and adapting said reject station with means to prevent said component from escaping said reject station. 2. The method for rejecting a component from a pick/place head in a component placement machine as recited in claim 1, the steps further comprising: rejecting said picked component into said reject station when said picked component is determined to be non-placeable. 3. An apparatus for retaining a rejected component from a pick/place head in a component placement machine, the apparatus comprising: a reject station mounted in a location accessible by said pick/place head; and at least one flap mounted contiguous with said reject station, wherein said at least one flap dampens the force in which said component impacts said reject station, further wherein said at least one flap prevents said component from escaping said reject station. 4. The apparatus of claim 3, wherein said reject station is mounted in said component placement machine. 5. The apparatus of claim 3, wherein said reject station is mounted contiguous with said pick/place head. 6. An apparatus for retaining rejected components in a component placement machine comprising: a reservoir for retaining said rejected components; and means adjacent to said reservoir, wherein said means is configured to absorb adequate energy from said rejected component upon its passage through said means, further wherein said means prevents said rejected component from passing back through said means thereby retaining said rejected component in said reservoir. | BACKGROUND OF THE INVENTION 1. Technical Field This invention relates to component placement machines and, more particularly, to an apparatus used for rejection of a component during the placement cycle. 2. Related Art The use of sophisticated placement machines in manufacturing printed circuit or similar cards, boards, panels, etc. is well known. The term printed circuit board (PCB) as used herein refers to any such electronic packaging structure. Typically, reels of tape-mounted circuit components are supplied to the placement machine by multiple feeders. Each feeder holds a reel of components and each feeder assembly provides components at a pick station. A housing carrying one or more pick/place heads mounted on a frame, each pick/place head having a vacuum spindle equipped with a nozzle, may be moved in the X and Y axes in a plane above the PCB being populated. Each vacuum spindle may be moved in the Z-axis (e.g., in and out from an extended to a retracted position). Each nozzle is sized and otherwise configured for use with each different size and style of component to be placed by the machine. In operation, the housing carrying the frame is moved to the pick station and the nozzle of one of the pick/place heads is positioned over the tape-mounted component. The nozzle is lowered, via its associated vacuum spindle, to a point where, upon application of vacuum, the component is removed from its backing tape and held tightly against the nozzle orifice. The component is then brought to a vision system where one or more images of the component are taken and then processed. Analysis of the image(s) determines whether the component is placeable. Typically, a placeability decision is based on a comparison of the image to predetermined mechanical parameters for each component. If the component is placeable, the pick/place head is moved to a point over the printed circuit board being assembled and the component deposited on the printed circuit board at a predetermined location. If a component is non-placeable, it is rejected and deposited to a reject station. The mechanical parameters used for comparison may include, but are not limited to, lead length, lead width, lead spacing, component size, the number of leads, etc. It is also known in the art to use a gripping mechanism that may be extended and retracted in place of, or in addition to, the vacuum spindle and nozzle. This reject station may be a dump bucket, a reject feeder, or a matrix tray. Dump buckets typically are mounted somewhere accessible to the pick/place head within the placement machine or mounted on the housing contiguous with the pick/place head. The pick/place head carrying a rejected component will place the component on to the reject feeder, or into a pocket of the matrix using the vacuum spindle. However, when the pick/place head must reject the component into a dump bucket, it drops the component from the vacuum spindle often using a combination of vacuum removal and “airkiss”. Many times components rejected in this manner miss the dump bucket or bounce out of the dump bucket upon depositing therein and ultimately end up else where in the machine. This results in poor product, jammed feeders, and poor production rates. A need exists for an improved rejection station that overcomes the aforementioned, and other, deficiencies in the art. SUMMARY OF THE INVENTION The present invention provides an improvement in the way that non-placeable components are handled in a component placement machine when rejected into a dump bucket style reject station. The inventive apparatus allows the dump bucket to retain the rejected components by attaching a flap to the dump bucket. The flap dampens the force of the component as it enters the dump bucket and then prevents the component from escaping the dump bucket once the component passes by the flap. Therefore, with the flap attached to the dump bucket, components no longer escape the dump bucket resulting in inter alia better product and production rates of the placement machine. A first general aspect of the present invention is a method for rejecting a component from a pick/place head in a component placement machine, the steps comprising: providing a component placement machine comprising a housing adapted for movement along an X and a Y axis above a printed circuit board and having a frame attached thereto, said frame having a one or more pick/place heads disposed thereupon; providing a vision system comprising a camera accessible to said one or more pick/place heads; picking a component from a supply of components using at least one of said one or more of pick/place heads; capturing an image of said picked component, and processing said captured image to determine whether said picked component is placeable or non-placeable; providing a reject station adapted to receive a component; adapting said reject station with means to reduce the force upon which said component impacts said reject station; and adapting said reject station with means to prevent said component from escaping said reject station. A second general aspect of the present invention is a apparatus for retaining a rejected component from a pick/place head in a component placement machine, the apparatus comprising: a reject station mounted in a location accessible by said pick/place head; and at least one flap mounted contiguous with said reject station, wherein said at least one flap dampens the force in which said component impacts said reject station, further wherein said at least one flap prevents said component from escaping said reject station. A third general aspect of the present invention is an apparatus for retaining rejected components in a component placement machine comprising: a reservoir for retaining said rejected components; and means adjacent to said reservoir, wherein said means is configured to absorb adequate energy from said rejected component upon its passage through said means, further wherein said means prevents said rejected component from passing back through said means thereby retaining said rejected component in said reservoir. BRIEF DESCRIPTION OF THE DRAWINGS A complete understanding of the present invention may be obtained by reference to the accompanying drawings, when considered in conjunction with the subsequent detailed description, in which: FIG. 1A is a top, perspective view of a related art dump bucket; FIG. 1B is a side, sectional view FIG. 1A, including a spindle; FIG. 2A is a top, perspective sectional view of a related art reject station that may be mounted contiguous with the pick/place head; FIG. 2B is a side, sectional view FIG. 2A, including a spindle; FIG. 3A is a top, perspective view of a first embodiment of a component rejection station, in accordance with the present invention; FIG. 3B is a side, sectional view FIG. 3A, including a spindle; FIG. 4A is a top, perspective view of a second embodiment of a component rejection station, in accordance with the present invention; and FIG. 4B is a side, sectional view FIG. 4A, including a spindle. DETAILED DESCRIPTION OF THE INVENTION Although certain embodiment of the present invention will be shown and described in detail, it should be understood that various changes and modifications may be made without departing from the scope of the appended claims. The scope of the present invention will in no way be limited to the number of constituting components, the materials thereof, the shapes thereof, the relative arrangement thereof, etc., and are disclosed simply as an example of an embodiment. The features and advantages of the present invention are illustrated in detail in the accompanying drawings, wherein like reference numerals refer to like elements throughout the drawings. The present invention pertains to rejection of a component in a component placement machine having a housing with a frame upon which one or more pick/place heads are mounted for assembling printed circuit boards. The component placement machine includes a reject station, which may be a dump bucket located within the placement machine accessible to the pick/place head or it may be mounted on the housing contiguous with the pick/place heads. The inventive apparatus includes a flap contiguous with the reject station which acts to dampen the force of the component as it enters the reject station and then prevents the component from escaping the reject station once the component passes by the flap. The type of components that typically are rejected and stored by the invention are electronic circuit components with a weight in the range from approximately 50 micrograms to 15 grams. Turning now to FIG. 1A, which depicts a dump bucket 10 that would be mounted in a machine accessible to the pick/place head from the related art, said dump bucket 10 includes an opening 20 that leads to a reservoir 25 for retaining rejected components(s) 50 (See e.g., FIG. 1B). The side sectional view in FIG. 1B shows a vacuum spindle 30 with nozzle 40 having just deposited a rejected component 50 into the reservoir 25 of the dump bucket 10. A trajectory path 60 of the rejected component 50 shows that upon the impact point 61 of the component 50 on a portion of the reservoir 25, that in many cases the component 50 then bounces out of the opening 20 of the reservoir 25 and dump bucket 10. Similarly, FIGS. 2A and 2B depict a second embodiment of a dump bucket 10 that would be mounted contiguous to the pick/place head in the related art, wherein the same shortcoming exists. That is upon the depositing of the rejected component 50, on many occasions, the component 50 ultimately ends up outside the dump bucket 10. One trajectory path 60 is shown as an example of one typical path that the component may take. That is the component 50 makes a series of impacts 61A, 61B, 61C, 61D on various parts of the reservoir 25, or other parts of the dump bucket 10, ultimately ending up beyond the opening 20 of the dump bucket 10. It should be apparent to those of ordinary skill in the art, that while some rejected components 50 are retained within the reservoir 25 of the dump bucket 10, one or more components 50 clearly will be ejected out of the dump bucket 10 as shown in FIGS. 1B and 2B. The present invention corrects this deficiency by ensuring that no components 50 escape the dump bucket 10. Referring first to FIG. 3A there is shown a top, perspective view of a first embodiment of a dump bucket 10, or component rejection station, in accordance with the present invention, with opening 20, adapted with a flap 80. FIG. 3B is a side, sectional view of FIG. 3A and includes the path 60 of the component 50 as it is rejected from the vacuum spindle 30 of nozzle 40. The vacuum spindle 30 releases the component 50 by removing vacuum from the nozzle 40. Vacuum spindle 30 may also release the component 50 by a combination of removing vacuum from the nozzle 40 and applying an airkiss, a slight flow of air, to component 50 via nozzle 40. Component 50 becomes disengaged from nozzle 40 and drops on to flap 80. The first impact of the component 50 is denoted 61A. Flap 80 is then deflected allowing component 50 to pass through the opening 20 into the bottom of dump bucket 10. A second impact 61B of the component is shown at the bottom of the reservoir 25. When component 50 impacts flap 80, flap 80 absorbs force from component 50 slowing the descent of component 50. Component 50 may then continue to bounce within dump bucket 10. Subsequent impact of the component 50 upon the underside of the flap 80 is shown 61C. However since the force of component 50 was reduced by flap 80 upon passage through opening 20, it does not have sufficient energy to pass back through opening 20 via flap 80. The component 50 ultimately comes to rest upon the bottom of the reservoir 25, as shown at 61D. Referring next to FIG. 4A which depicts a second embodiment of a component rejection station which is mounted contiguous with pick and place spindles, in accordance with the present invention. In this case, the component rejection station includes a dump bucket 10, with opening 20, adapted with flap 80. FIG. 4B, similarly, is a side sectional view of FIG. 4A and includes the path 60 of the component 50 as it is rejected from the vacuum spindle 30 of nozzle 40. The various impacts of the rejected component 50 are denoted 61 (e.g., 61A, 61B, 61C, 61D, 61E, 61F). The vacuum spindle 30 releases the component 50 by removing vacuum from the nozzle 40. Vacuum spindle 30 may also release the component 50 by a combination of removing vacuum from the nozzle 40 and applying an airkiss, a slight flow of air, to component 50 via nozzle 40. Component 50 becomes disengaged from nozzle 40 and drops on to flap 80. The impact upon the flap 80 is denoted 61A. Flap 80 is then deflected allowing component 50 to pass through the opening 20 into the bottom of the dump bucket 10. When component 50 impacts 61A flap 80, flap 80 absorbs force from component 50 slowing the descent of component 50. Component 50 may then continue to bounce within the reservoir 25 of the dump bucket 10. However since the force of component 50 was reduced by flap 80 upon passage through opening 20, it does not have sufficient energy to pass back through opening 20 via flap 80. Numerous subsequent impacts of the component 50 are shown as 61B, 61C, 61D 61E, while the final resting location of the component 50 upon the bottom of the reservoir 25 is denoted as 61F. It should be apparent that although two embodiments of the present invention are depicted there are other embodiments available that provide the requisite improvements of the present invention. For example, the flap 80, while depicted as either a single flap 80 (e.g., FIGS. 4A, 4B) or two opposing flaps 80 (e.g., FIGS. 3A, 3B), may have other embodiments. The flap 80 may be, for example, more than two flaps 80. In the embodiments where there is a plurality of flaps 80, the various flaps 80 may also abut or overlap each other. Further, the flap(s) 80 may, depending on the configuration and shape of the opening 20 and other parts of the dump bucket 10, not abut, or overlap, each other, or even completely cover the opening 20. Likewise, there are various materials in which the flap 80 may be constructed. The flap 80 should be of a resilient, energy-absorbing material so that various sized rejected components 50 may pass by the flap 80 upon initial contact, yet cannot pass through a second time, or any subsequent time, upon the rebounding of the component 50 around the reservoir 25 of the dump bucket 10. One embodiment the flap 80 may be made of Mylar®. Alternatively, the flap 80 may be made of multiple materials. Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Technical Field This invention relates to component placement machines and, more particularly, to an apparatus used for rejection of a component during the placement cycle. 2. Related Art The use of sophisticated placement machines in manufacturing printed circuit or similar cards, boards, panels, etc. is well known. The term printed circuit board (PCB) as used herein refers to any such electronic packaging structure. Typically, reels of tape-mounted circuit components are supplied to the placement machine by multiple feeders. Each feeder holds a reel of components and each feeder assembly provides components at a pick station. A housing carrying one or more pick/place heads mounted on a frame, each pick/place head having a vacuum spindle equipped with a nozzle, may be moved in the X and Y axes in a plane above the PCB being populated. Each vacuum spindle may be moved in the Z-axis (e.g., in and out from an extended to a retracted position). Each nozzle is sized and otherwise configured for use with each different size and style of component to be placed by the machine. In operation, the housing carrying the frame is moved to the pick station and the nozzle of one of the pick/place heads is positioned over the tape-mounted component. The nozzle is lowered, via its associated vacuum spindle, to a point where, upon application of vacuum, the component is removed from its backing tape and held tightly against the nozzle orifice. The component is then brought to a vision system where one or more images of the component are taken and then processed. Analysis of the image(s) determines whether the component is placeable. Typically, a placeability decision is based on a comparison of the image to predetermined mechanical parameters for each component. If the component is placeable, the pick/place head is moved to a point over the printed circuit board being assembled and the component deposited on the printed circuit board at a predetermined location. If a component is non-placeable, it is rejected and deposited to a reject station. The mechanical parameters used for comparison may include, but are not limited to, lead length, lead width, lead spacing, component size, the number of leads, etc. It is also known in the art to use a gripping mechanism that may be extended and retracted in place of, or in addition to, the vacuum spindle and nozzle. This reject station may be a dump bucket, a reject feeder, or a matrix tray. Dump buckets typically are mounted somewhere accessible to the pick/place head within the placement machine or mounted on the housing contiguous with the pick/place head. The pick/place head carrying a rejected component will place the component on to the reject feeder, or into a pocket of the matrix using the vacuum spindle. However, when the pick/place head must reject the component into a dump bucket, it drops the component from the vacuum spindle often using a combination of vacuum removal and “airkiss”. Many times components rejected in this manner miss the dump bucket or bounce out of the dump bucket upon depositing therein and ultimately end up else where in the machine. This results in poor product, jammed feeders, and poor production rates. A need exists for an improved rejection station that overcomes the aforementioned, and other, deficiencies in the art. | <SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides an improvement in the way that non-placeable components are handled in a component placement machine when rejected into a dump bucket style reject station. The inventive apparatus allows the dump bucket to retain the rejected components by attaching a flap to the dump bucket. The flap dampens the force of the component as it enters the dump bucket and then prevents the component from escaping the dump bucket once the component passes by the flap. Therefore, with the flap attached to the dump bucket, components no longer escape the dump bucket resulting in inter alia better product and production rates of the placement machine. A first general aspect of the present invention is a method for rejecting a component from a pick/place head in a component placement machine, the steps comprising: providing a component placement machine comprising a housing adapted for movement along an X and a Y axis above a printed circuit board and having a frame attached thereto, said frame having a one or more pick/place heads disposed thereupon; providing a vision system comprising a camera accessible to said one or more pick/place heads; picking a component from a supply of components using at least one of said one or more of pick/place heads; capturing an image of said picked component, and processing said captured image to determine whether said picked component is placeable or non-placeable; providing a reject station adapted to receive a component; adapting said reject station with means to reduce the force upon which said component impacts said reject station; and adapting said reject station with means to prevent said component from escaping said reject station. A second general aspect of the present invention is a apparatus for retaining a rejected component from a pick/place head in a component placement machine, the apparatus comprising: a reject station mounted in a location accessible by said pick/place head; and at least one flap mounted contiguous with said reject station, wherein said at least one flap dampens the force in which said component impacts said reject station, further wherein said at least one flap prevents said component from escaping said reject station. A third general aspect of the present invention is an apparatus for retaining rejected components in a component placement machine comprising: a reservoir for retaining said rejected components; and means adjacent to said reservoir, wherein said means is configured to absorb adequate energy from said rejected component upon its passage through said means, further wherein said means prevents said rejected component from passing back through said means thereby retaining said rejected component in said reservoir. | 20040420 | 20061212 | 20051103 | 71057.0 | 0 | ARBES, CARL J | COMPONENT REJECTION STATION | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,828,158 | ACCEPTED | Elastic coupling | An elastic coupling capable of sufficiently absorbing a shake of a steering shaft in its axis direction to prevent a driver from feeling uncomfortable due to the shake is provided. A rubber elastic body including lubricant is provided between an outer circumference of an inner casing having a roughly cross shape in section and an inner circumference of an outer casing while the outer casing and the rubber elastic body are enabled to slide in their axis direction so as to absorb a shake in the axis direction from a steering gear box side. | 1. An elastic coupling, comprising: a cylinder member connected to one of a steering gear box side and a steering wheel side and opens toward the other; a shaft member connected to the other one of the steering gear box side and the steering wheel side and inserted in the cylinder member with a predetermined gap formed between the shaft member and a bottom of the cylinder member to limit relative rotation thereof; a first elastic body provided between an inner circumferential surface of the cylinder member and an outer circumferential surface of the shaft member; and a sliding portion that allows a relative movement of the cylinder member and the shaft member in an axis direction, the sliding portion being provided at least one of between the inner circumferential surface of the cylinder member and the first elastic body and between the outer circumferential surface of the shaft member and the first elastic body. 2. The elastic coupling according to claim 1, wherein a protrusion is formed in the outer circumference of the shaft member while a concave groove is formed in the inner circumference of the cylinder member, and the protrusion of the outer circumference of the shaft member is located inside the concave groove of the inner circumference of the cylinder member to limit relative rotation. 3. The elastic coupling according to claim 1, wherein an upper end of the cylinder member is fixed to a yoke of a universal joint while the above shaft member is provided on a top end of an intermediate shaft. 4. The elastic coupling according to claim 1, wherein the first elastic body includes lubricant. 5. The elastic coupling according to claim 4, wherein the lubricant is any one of paraffin, silicon-based oil or a synthetic grease. 6. The elastic coupling according to claim 1, wherein lubricant is applied to the sliding portion. 7. The elastic coupling according to claim 1, wherein a second elastic body is provided between the bottom of the cylinder member and the shaft member. 8. The elastic coupling according to claim 1, wherein a flange portion extending on the inner circumference side is formed on an opening end of the cylinder member and a third elastic body is provided between the flange portion and the shaft member. 9. An elastic coupling, comprising: a coupling provided on a steering shaft and having a cylinder member and a shaft member inserted in the cylinder member to limit relative rotation thereof; and a first elastic body fixed on an outer circumferential surface of the shaft member and on an inner circumference of the cylinder member to allow the shaft member and the cylinder member to slide with respect to one another to absorb shake in an axis direction of the steering shaft. 10. The elastic coupling according to claim 9, further comprising: a second elastic body provided between a bottom of the cylinder member and the shaft member, the second elastic body returning the cylinder member and the shaft member to initial positions thereof. 11. The elastic coupling according to claim 9, further comprising: a third elastic body provided between a flange portion provided at an opening end of the cylinder member and extending on the inner circumference side, wherein the shaft member returns the cylinder member and the shaft member to initial positions thereof. 12. The elastic coupling according to claim 9, wherein the first elastic body and the shaft member are vulcanized and formed into one body. 13. An elastic coupling, comprising: a coupling provided on a steering shaft and having a cylinder member and a shaft member inserted in the cylinder member to limit relative rotation thereof; and a first elastic body fixed on an inner circumferential surface of the cylinder member and on an outer circumference of the shaft member to allow the cylinder member and the shaft member to slide with respect to one another to absorb shake in an axis direction of the steering shaft. 14. The elastic coupling according to claim 13, further comprising: a second elastic body provided between a bottom of the cylinder member and the shaft member, the second elastic body returning the cylinder member and the shaft member to initial positions thereof. 15. The elastic coupling according to claim 13, further comprising: a third elastic body provided between a flange portion provided at an opening end of the cylinder member and extends on the inner circumference side, wherein the shaft member returns the cylinder member and the shaft member to initial positions thereof. 16. The elastic coupling according to claim 13, wherein the first elastic body and the cylinder member are vulcanized and formed into one body. | CROSS REFERENCE TO RELATED APPLICATION This Nonprovisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 2003-116096 filed in Japan on Apr. 21, 2003, the entire contents of which are hereby incorporated by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elastic coupling provided in a steering shaft of a steering device for a vehicle. 2. Description of the Related Art As is known, in a structure of a steering device of a vehicle, a steering shaft connects a steering gear box provided on a cross member of a body of the vehicle with a steering wheel provided in a driver's seat, and rotation of the steering wheel is transmitted to the steering gear box via the steering shaft to steer right and left wheels by means of the steering gear box. The steering shaft is provided with an elastic coupling in order to prevent an input from a road, a shake (vibration) of an engine or the like from being transmitted to the steering wheel side (see JP 9-196077A, for example). In a steering device disclosed in JP 9-196077A, a steering coupling as an elastic coupling is incorporated in an intermediate shaft connecting a steering gear box with a main shaft. The steering coupling comprises cylindrical metal fittings connected on the steering gear box side, shaft metal fittings connected on the main shaft side and a rubber elastic body provided between an inner circumference of the cylindrical metal fittings and an outer circumference of the shaft metal fittings. The inner circumference of the cylindrical metal fittings and the outer circumference of the shaft metal fittings are respectively formed into a roughly cross shape in section. The rubber elastic body has a corresponding shape in section and is provided between the both metal fittings. This allows rotation from the steering wheel to be transmitted to the steering gear box side through the rubber elastic body and a shimmy from the steering gear box side (a shake around a rotation shaft) to be absorbed by elastically changing a shape of the rubber elastic body. As is known, a steering gear box is provided on a cross member of a body of a vehicle, and thereby, there is a phenomenon that the steering gear box is displaced up and down and right an left due to bending of a cross member per se or bending of a mounting portion of the steering gear box when the steering gear box receives an input from a road through a member such as a wheel to be steered, a tie rod or the like. Such displacement is transmitted to a steering coupling as a shake in an axis direction. In the steering coupling disclosed in JP 9-196077A, however, there is a problem that the shake in an axis direction is transmitted since a shimmy, which is a shake around a rotation shaft, is only assumed. In more detail, a rubber elastic body of a steering coupling is vulcanized and adhered to an inner surface of cylindrical metal fittings while pressured and inserted in an outer circumferential surface of shaft metal fittings, so that it cannot move relatively to any of the cylindrical metal fittings and the shaft metal fittings. Therefore, an operation of absorbing a shake in an axis direction has only an effect that the rubber elastic body is slightly elastically changed in shape in an axis direction, so that most of the shake is transmitted as it is. As a result, there is a problem caused that a driver handling a steering wheel feels uncomfortable. SUMMARY OF THE INVENTION An object of the invention is to provide an elastic coupling capable of preventing a driver from feeling uncomfortable due to a shake by completely absorbing shake of a steering shaft in the axis direction thereof. In order to achieve the above object, one aspect of the invention is an elastic coupling comprising: a cylinder member, which is connected to one of a steering gear box side and a steering wheel side and opens toward the other; a shaft member, which is connected to the other one of the steering gear box side and the steering wheel side and which is inserted in the cylinder member with a predetermined gap formed between the shaft member and a bottom of the cylinder member; a first elastic body provided between an inner circumferential surface of the cylinder member and an outer circumferential surface of the shaft member so that relative rotation of the cylinder member and the shaft member may be limited by means of resilience; a sliding portion, that enables relative movement of the cylinder member and the shaft member in an axis direction, provided at least either between the inner circumferential surface of the cylinder member and the first elastic body or between the outer circumferential surface of the shaft member and the first elastic body. In the above structure, rotation of the steering wheel is transmitted to the steering gear box side through the first elastic body provided between the cylinder member and the shaft member to perform an operation of steering a wheel to be steered. On the other hand, when a shimmy, which is a shake around a rotation shaft, is transmitted from the steering gear box side, the transmitted shimmy is absorbed by elastic change in shape of the first elastic body. When a shake in the axis direction is transmitted from the steering gear box side, any one of the cylinder member and the shaft member, which is connected to the steering gear box side, shakes in the axis direction. The cylinder member and the shaft member, however, move relatively in the axis direction through the sliding portion. As a result, the shake in the axis direction is absorbed without transmitted to the other one of the cylinder member and the shaft member. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description given hereinbelow and accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: FIG. 1 is an entire structural view of a steering device in accordance with an embodiment of the present invention; FIG. 2 is an enlarged sectional view of an elastic coupling; FIG. 3 is also a sectional view of the elastic coupling along the line III-III in FIG. 2; and FIG. 4 is also a sectional view of the elastic coupling along the line IV-IV in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION A mode for carrying out the invention of an elastic coupling in which the invention is embodied will be described hereinafter. FIG. 1 is an entire structural view of a steering device in accordance with this embodiment. In FIG. 1, a steering device is shown in the view from a side of a vehicle. Reference numeral 1, in FIG. 1, denotes a cross member provided inside an engine compartment of the vehicle in the width direction thereof. Both ends of the cross member 1 are fixed to right and left side members through a rubber bush in this embodiment although this is not shown in the drawing. An object of the above structure is to reduce shake and noise in the vehicle. In the above structure, the rubber bush absorbs shake transmitted to the cross member through a suspension so that the shake is prevented from being transmitted to a compartment of the vehicle via a side member. A steering gear box 2 is fixed on the cross member 1 by means of a bolt and is connected to right and left wheels to be steered through a member such as a tie rod provided on the right and left sides although this is not shown in the drawing. On the other hand, a steering column 3 is provided facing a driver's seat in a compartment of the vehicle so as to be fixed by means of a supporting bracket 5 to a deck cross member 4 bridged in a body of the vehicle in the width direction thereof. In the steering column 3, a main shaft 6 is held so as to be able to rotate. A steering wheel 7 is fixed on an upper end of the main shaft 6. A lower end of the main shaft 6 is connected to an upper end of the intermediate shaft 9 through a universal joint 8. A lower end of the intermediate shaft 9 is connected to an input shaft 2a of the above-mentioned steering gear box 2 through a universal joint 10. Accordingly, the input shaft 2a of the steering gear box 2 is rotated through the main shaft 6 and the intermediate shaft 9 when the steering wheel 7 is rotated, and then, the rotation of the input shaft 2a is converted in the gear box 2 into right-and-left linear movement, so that the right and left wheels to be steered through the tie rod with a hydraulic assist in the power steering mechanism. An elastic coupling 11 is provided in the upper part of the above-mentioned intermediate shaft 9. FIG. 2 is an enlarged sectional view of the elastic coupling 11. FIG. 3 is also a sectional view of the elastic coupling 11 along the line III-III in FIG. 2. FIG. 4 is also a sectional view of the elastic coupling 11 along the line IV-IV in FIG. 2. A structure of the elastic coupling 11 will be described in detail hereinafter in accordance with these drawings. An inner casing 12 (a shaft member) of the elastic coupling 11 is in the shape of a cylinder and has an axis L common to the intermediate shaft 9. The lower part of the inner casing 12 is welded and fixed so as to be outwardly fitted to the upper end of the intermediate shaft 9. An outer casing 13 (a cylinder member), which is in the shape of a cylinder and has the common axis L, is provided with a play on the outer circumference side of the inner casing 12. The upper end of the outer casing 13 is welded and fixed to a yoke 8a of the universal joint 8. Four protrusions 12a are formed on the outer circumference of the inner casing 12 in the axis direction with a space of 90 degrees about the axis L so as to be in a roughly cross shape in section. On the other hand, four concave grooves 13a are formed on the inner circumference of the outer casing 13 in the axis direction with a space of 90 degrees about the axis L in order to correspond to the respective protrusions 12a so as to be in a roughly cross shape in section. Each of the protrusions 12a of the inner casing 12 is thus located in each of the concave grooves 13a of the outer casing 13. A gap S1, which is roughly even all over, is formed between an outer circumferential surface of the inner casing 12 including the protrusions 12a and an inner circumferential surface of the outer casing 13 including the concave grooves 13a. In the gap S1, a rubber elastic body 14 whose shape in section corresponds to the above-mentioned gap S1 is inserted. The rubber elastic body 14 is vulcanized and formed into one body with the inner casing 12 while it is formed into a member separate from the outer casing 13 so as to be inserted therein. The inner casing 12 and the outer casing 13 thus compress and change in shape the rubber elastic body 14 between a side surface of the protrusion 12a and a side surface of the concave groove 13a, which are opposed each other with a predetermined space, limiting relative rotation about the axis L. At the same time, they enable the outer circumferential surface of the rubber elastic body 14 and the inner circumferential surface of the outer casing 13 to be in contact each other and slide so as to relatively move in the axis direction. That is to say, a sliding portion A is formed between the outer circumferential surface of the rubber elastic body 14 and the inner circumferential surface of the outer casing 13, which may be in contact each other and slide, in this embodiment. Here, the rubber elastic body 14 in this embodiment is arranged to include lubricant having an operation of reducing a coefficient of friction so that only small power is used for easily carrying out the slide between the rubber elastic body 14 and the outer casing 13 without generating any abnormal sound. Paraffin, silicon-based oil, a variety of synthetic grease and such can be used as the lubricant. It is possible to select any of such lubricant to be included in the rubber elastic body 14 in order to attain a desired coefficient of friction. As for a method of reducing the coefficient of friction, lubricant such as grease may be applied between the outer circumferential surface of the rubber elastic body 14 and the inner circumferential surface of the outer casing 13 instead of the above-mentioned method relating to a material of the rubber elastic body 14. As shown in FIG. 2, the yoke 8a of the universal joint 8 closes the upper end of the outer casing 13, which opens downwardly (toward the intermediate shaft 9). An upper stopper surface 15a (a bottom part) is formed on the upper end of the outer casing 13. The opening end of the outer casing 13 extends to the inner circumference side. The upper surface of the extended portion is defined as a lower stopper surface 15b (a flange portion). The upper stopper surface 15a is opposed to an upper stopper surface 16a formed on the upper end of each protrusion 12a of the inner casing 12 with a gap S2 in the axis direction. Similarly, the lower stopper surface 15b is opposed to a lower stopper surface 16b formed on the lower end of each protrusion 12a of the inner casing 12 with a gap S3 in the axis direction. The both gaps S2 and S3 are assumed to be in the same size in this embodiment, but the size may be different. The length of the rubber elastic body 14 in the axis direction is the same as that of the inner casing 12 as a whole, and the part corresponding to the above length is defined as a main body 14a (a first elastic body). From the main body 14a, provided are an upper centering portion 14b (a second elastic body) and a lower centering portion 14c (a third elastic body) to respectively extend upwardly and downwardly at a place corresponding to a corner of each protrusion 12a and concave groove 13a. The upper centering portion 14b is located in the above-mentioned gap S2 to be provided between the upper stopper surfaces 15a and 16a. The lower centering portion 14c is similarly located in the above-mentioned gap S3 to be provided between the lower stopper surfaces 15b and 16b. Providing the centering portions 14b and 14c of the rubber elastic body 14 between the opposite upper stopper surfaces 15a and 16a and between the opposite lower stopper surfaces 15b and 16b as described above allows the inner casing 12 and the outer casing 13 to be held in predetermined positions in the axis direction and further allows the both centering portions 14b and 14c to be compressed and changed in shape to relatively move in the axis directions as described above. A structure of the steering device in this embodiment is as described above. In the structure, a variety of shake occurring on the steering gear box 2 side are absorbed by means of an elastic coupling 11 as described below. First, in the case that the steering wheel 7 is rotated, the rotation is transmitted to the outer casing 13 of the elastic coupling 11 through the main shaft 6 and the universal joint 8. At that time, one side surface of the respective concave grooves 13a of the outer casing 13 (a side surface on the reverse rotation side) pressures an opposed side surface of the respective protrusions 12a of the inner casing 12 (equally, a side surface on the reverse rotation side), compressing and changing in shape the main body 14a of the rubber elastic body 14. Therefore, the inner casing 12 rotates together in accordance with the direction that the outer casing 13 rotates. The rotation is further inputted to the steering gear box 2 from the intermediate shaft 9 to steer the right and left wheels to be steered. In the case that a shimmy occurs in the input shaft 2a of the steering gear box 2 in receiving an input from a road or the like, the shimmy, which has occurred, is transmitted to the inner casing 12 of the elastic coupling 11 through the intermediate shaft 9. A shake due to the shimmy is switched between the clockwise and counterclockwise directions about a rotation axis in a short cycle, different from the above-described continuous one-way rotating operation. Accordingly, compressing and changing in shape the main body 14a of the rubber elastic body 14 allows the shake to be absorbed, and thereby, the shimmy can be prevented from being transmitted to the steering wheel 7 side. On the other hand, in the case that the steering gear box 2 receives an input from a road through a member such as a wheel to be steered, a tie rod or the like, a phenomenon that the steering gear box 2 is displaced up and down and right and left occurs due to bending of the cross member 1 per se or bending of a mounting portion of the gear box 2. Such displacement causes a shake of the input shaft 2a of the steering gear box 2 in the axis direction. The shake having occurred in the axis direction is transmitted to the inner casing 12 of the elastic coupling 11 through the intermediate shaft 9. At that time, the rubber elastic body 14 also shakes in the axis direction together with the inner casing 12. The inner casing 12 and the outer casing 13, however, relatively move in the axis direction since the outer circumferential surface of the main body 14a of the rubber elastic body 14 and the inner circumferential surface of the outer casing 13 slide each other, so that the shake of the inner casing 12 in the axis direction is absorbed without being transmitted to the outer casing 13. The top end of the inner casing 12 (the upper stopper surface 16a) repeats movement toward and away from the top end of the outer casing 13 (the upper stopper surface 15a) in accordance with the relative movement in the axis direction. The upper centering portion 14b provided between the above top ends, however, prevents the direct collision, so that the noise of a strike due to the collision between metals can be restrained in advance. On the other hand, the centering portions 14b and 14c of the rubber elastic body 14 return to their original sectional shapes due to the resilience of themselves after the shake in the axis direction disappears. The inner casing 12 and the outer casing 13 are thus returned to the initial positions (a neutral position where the gaps S2 and S3 are equal as described above), and then, an operation of absorbing the shake similar to the above is performed when a shake in the axis direction occurs again after the return. As is clear from the above description, the resilience of the centering portions 14b and 14c of the rubber elastic body 14 should have an upper limit, which is a degree of not disturbing the relative movement of the inner casing 12 and the outer casing 13 in the axis direction, and a lower limit, which is a degree of enabling the inner casing 12 and the outer casing 13 to return to the initial positions. As for a material of the rubber elastic body 14, a material having an optimal elastic modulus is selected in view of absorbing of a shimmy, and therefore, the resilience within the above range should be given to the centering portions 14b and 14c, premising the above elastic modulus. In this embodiment, adjusting the area of the centering portions 14b and 14c (concretely, the total area of the upper and lower centering portions 14b and 14c) allows the proper resilience to be achieved. As a result, the inner casing 12 and the outer casing 13 relatively move without being disturbed by the centering portions 14b and 14c to perform a secure operation of absorbing the shake, while they are surely returned to the initial positions after the shake disappears. As described in detail hereinbefore, in the steering device in this embodiment, the rubber elastic body 14 is formed as a separate member from the outer casing 13 of the elastic coupling 11 to be able to slide in the axis direction, and therefore, the elastic coupling 11 can perform an operation of absorbing a shake in the axis direction, the shake caused by bending of the cross member 1 per se or bending of the mounting portion of the gear box 2, in addition to an operation as a shimmy dumper for absorbing a shimmy. Especially in the vehicle in this embodiment, there is a characteristic that displacement of a position of the steering gearbox 2, and thereby, a shake in the axis direction easily occur, compared with the case of a normal structure of a body of a vehicle in which the cross member is rigid-connected, since a body of the vehicle in this embodiment is constructed so that the cross member 1 is fixed to the side member through a rubber bush. The shake having occurred, however, can be surely absorbed by the elastic coupling 11, so that such harmful effect as described above can be prevented. Therefore, the elastic coupling 11 can sufficiently absorb a shake in the axis direction to avoid uncomfortableness of a driver due to a shake of the steering wheel 7. Furthermore, the inner casing 12 and the outer casing 13 are returned to their initial positions by means of the centering portions 14b and 14c of the rubber elastic body 14 after the shake in the axis direction disappears, so that a stable operation of absorbing the shake can be performed all the time. Moreover, the upper centering portion 14b of the rubber elastic body 14 can also operate to prevent a collision between the inner casing 12 and the outer casing 13, which is caused in accordance with the shake in the axis direction. There is thus an advantage obtained such that the noise of a strike due to the collision between metals can be restrained, and thereby, the noise in a compartment of the vehicle can be reduced. On the other hand, compared with an elastic coupling in JP 9-196077A described as a prior art, the elastic coupling 11 in this embodiment has such a simple structure that the rubber elastic body 14 including lubricant is provided as a separate member from the outer casing 13 to be able to slide and the centering portions 14b and 14c are formed on the both of the upper and lower ends of the rubber elastic body 14. Accordingly, the elastic coupling 11 in this embodiment may be put into practice with little rise in cost to achieve the above-mentioned variety of superior operational effects. Furthermore, the shake-absorbing operation of the elastic coupling 11 allows the shake in the axis direction to hardly operate on the steering column 3, so that securing the strength as a countermeasure against the shake is not necessary for a supporting bracket 5 supporting the steering column 3. Therefore, in accordance with the elastic coupling 11 in this embodiment, there is also such an advantage obtained that the manufacturing cost can be rather reduced. The mode of the invention is not limited to the above embodiment although description of the embodiment has been completed above. For example, the elastic coupling 11 is provided on the intermediate shaft 9 of the steering device in the above-mentioned embodiment. The location for providing the elastic coupling 11 is, however, not limited to the above. The elastic coupling 11 may be provided on the input shaft 2a of the steering gear box 2 or the main shaft 6, for example. In the above-mentioned embodiment, the four protrusions 12a on the inner casing 12 side are engaged with the four concave grooves 13a on the outer casing 13 side through the rubber elastic body 14 so as to obtain functions of transmitting rotation and absorbing a shimmy. The engaging state between the inner casing 12 and the outer casing 13 is, however, not limited to the above. The protrusions 12a or the concave grooves 13a may be changed in number and may be provided with unequal space, for example. Moreover, in the above-mentioned embodiment, the rubber elastic body 14 is capable of sliding against the outer casing 13. The rubber elastic body 14, however, may be provided to slide against the inner casing 12 and formed into one body with the outer casing 13, or may be constructed so as to be capable of sliding against the both of the inner casing 12 and the outer casing 13, respectively. In the above-mentioned embodiment, the centering portions 14b and 14c are formed into one body with the rubber elastic body 14 so that the inner casing 12 and the outer casing 13 would be actively returned to their initial positions after the shake disappears. Such function is not necessarily required, however. The centering portions 14b and 14c may be omitted from the structure. The number, a shape and such of the centering portions 14b and 14c are not limited to the above embodiment even in the case of providing the centering portions 14b and 14c. For example, the centering portions 14b and 14c may be formed separately from the main body 14a of the rubber elastic body 14 or may be only provided on the two protrusions 12a and the two concave grooves 13a, which are opposed at an angle of 180 degrees, among the four protrusions 12a and the four concave grooves 13a. It is also possible to provide a Belleville spring or a coil spring in the gaps S2 and S3 instead of the centering portions 14b and 14c so as to obtain the similar operation. As described above, in accordance with the elastic coupling of the invention, a shake of the steering shaft in the axis direction can be sufficiently absorbed to prevent a driver from feeling uncomfortable due to the shake. Furthermore, in accordance with the elastic coupling of the invention, a sliding portion can be provided in a simple structure, resulting in reducing of a manufacturing cost, in addition to the effect mentioned above. In accordance with the elastic coupling of the invention, it is also possible to restrain the noise of a strike due to a collision between a cylinder member and a shaft member, so that the noise in a compartment of a vehicle can be reduced, in addition to the above effects. Moreover, in accordance with the elastic coupling of the invention, a shaft member and a cylinder member are returned to their initial positions by means of a second elastic body and a third elastic body after the shake in the axis direction disappears, so that a stable operation of absorbing the shake can be performed all the time, in addition to the above effects. The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to an elastic coupling provided in a steering shaft of a steering device for a vehicle. 2. Description of the Related Art As is known, in a structure of a steering device of a vehicle, a steering shaft connects a steering gear box provided on a cross member of a body of the vehicle with a steering wheel provided in a driver's seat, and rotation of the steering wheel is transmitted to the steering gear box via the steering shaft to steer right and left wheels by means of the steering gear box. The steering shaft is provided with an elastic coupling in order to prevent an input from a road, a shake (vibration) of an engine or the like from being transmitted to the steering wheel side (see JP 9-196077A, for example). In a steering device disclosed in JP 9-196077A, a steering coupling as an elastic coupling is incorporated in an intermediate shaft connecting a steering gear box with a main shaft. The steering coupling comprises cylindrical metal fittings connected on the steering gear box side, shaft metal fittings connected on the main shaft side and a rubber elastic body provided between an inner circumference of the cylindrical metal fittings and an outer circumference of the shaft metal fittings. The inner circumference of the cylindrical metal fittings and the outer circumference of the shaft metal fittings are respectively formed into a roughly cross shape in section. The rubber elastic body has a corresponding shape in section and is provided between the both metal fittings. This allows rotation from the steering wheel to be transmitted to the steering gear box side through the rubber elastic body and a shimmy from the steering gear box side (a shake around a rotation shaft) to be absorbed by elastically changing a shape of the rubber elastic body. As is known, a steering gear box is provided on a cross member of a body of a vehicle, and thereby, there is a phenomenon that the steering gear box is displaced up and down and right an left due to bending of a cross member per se or bending of a mounting portion of the steering gear box when the steering gear box receives an input from a road through a member such as a wheel to be steered, a tie rod or the like. Such displacement is transmitted to a steering coupling as a shake in an axis direction. In the steering coupling disclosed in JP 9-196077A, however, there is a problem that the shake in an axis direction is transmitted since a shimmy, which is a shake around a rotation shaft, is only assumed. In more detail, a rubber elastic body of a steering coupling is vulcanized and adhered to an inner surface of cylindrical metal fittings while pressured and inserted in an outer circumferential surface of shaft metal fittings, so that it cannot move relatively to any of the cylindrical metal fittings and the shaft metal fittings. Therefore, an operation of absorbing a shake in an axis direction has only an effect that the rubber elastic body is slightly elastically changed in shape in an axis direction, so that most of the shake is transmitted as it is. As a result, there is a problem caused that a driver handling a steering wheel feels uncomfortable. | <SOH> SUMMARY OF THE INVENTION <EOH>An object of the invention is to provide an elastic coupling capable of preventing a driver from feeling uncomfortable due to a shake by completely absorbing shake of a steering shaft in the axis direction thereof. In order to achieve the above object, one aspect of the invention is an elastic coupling comprising: a cylinder member, which is connected to one of a steering gear box side and a steering wheel side and opens toward the other; a shaft member, which is connected to the other one of the steering gear box side and the steering wheel side and which is inserted in the cylinder member with a predetermined gap formed between the shaft member and a bottom of the cylinder member; a first elastic body provided between an inner circumferential surface of the cylinder member and an outer circumferential surface of the shaft member so that relative rotation of the cylinder member and the shaft member may be limited by means of resilience; a sliding portion, that enables relative movement of the cylinder member and the shaft member in an axis direction, provided at least either between the inner circumferential surface of the cylinder member and the first elastic body or between the outer circumferential surface of the shaft member and the first elastic body. In the above structure, rotation of the steering wheel is transmitted to the steering gear box side through the first elastic body provided between the cylinder member and the shaft member to perform an operation of steering a wheel to be steered. On the other hand, when a shimmy, which is a shake around a rotation shaft, is transmitted from the steering gear box side, the transmitted shimmy is absorbed by elastic change in shape of the first elastic body. When a shake in the axis direction is transmitted from the steering gear box side, any one of the cylinder member and the shaft member, which is connected to the steering gear box side, shakes in the axis direction. The cylinder member and the shaft member, however, move relatively in the axis direction through the sliding portion. As a result, the shake in the axis direction is absorbed without transmitted to the other one of the cylinder member and the shaft member. | 20040421 | 20080108 | 20050127 | 70725.0 | 0 | BROWN, DREW J | ELASTIC COUPLING | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,828,254 | ACCEPTED | Shredder with pivoting housing for the shredder mechanism | The present invention relates to a shredder wherein the shredder housing can be pivoted between a generally horizontal orientation and a generally vertical orientation. | 1. A shredder comprising: a seat having a pivot guide; a shredder housing including a pivot mount; a shredder mechanism including a motor and cutter elements, the shredder mechanism enabling articles to be shredded to be fed into the cutter elements and the motor being operable to drive the cutter elements so that the cutter elements shred the articles fed therein, the shredder mechanism being mounted in the shredder housing; the shredder housing being constructed to be removably mounted to the seat in a generally horizontal orientation with the pivot mount removably engaged with the pivot guide; the pivot mount and the pivot guide being constructed to pivotally mount the shredder housing for pivotal movement between the generally horizontal orientation and a generally vertical orientation. 2. A shredder according to claim 1, wherein the pivot mount and the pivot guide are constructed to provide support to the shredder housing in the generally vertical orientation against movement thereof towards the generally horizontal orientation, thereby facilitating a user (a) lifting the shredder housing in the generally vertical orientation off the seat with the pivot mount disengaging from the pivot guide and (b) lowering the shredder housing in the generally vertical orientation onto the seat with the pivot mount engaging the pivot guide and the pivotally moving the shredder housing downwardly to the generally horizontal orientation. 3. A shredder according to claim 2, further comprising a handle provided on the shredder housing, the handle being constructed to be manually grasped for moving the shredder housing between the generally horizontal and generally vertical orientations on the seat and lifting and lowering the shredder housing off of and onto the seat. 4. A shredder according to claim 3, wherein the pivot guide includes a pair of pivot guides provided on opposing lateral sides of the seat and wherein the pivot mount includes a pair of pivot mounts provided on opposing lateral sides of the shredder housing. 5. A shredder according to claim 4, wherein the pivot guides are upwardly facing recesses. 6. A shredder according to claim 7, wherein each of the upwardly facing recesses has a generally vertical engagement surface provided in a bottom thereof, the pivot guides and the pivot mounts being constructed such that when the shredder mechanism housing is in the generally vertical orientation thereof the surfaces on the pivot mounts are engaged with the generally vertical engagement surfaces to provide support to the shredder mechanism housing in the generally vertical orientation against movement thereof towards the generally horizontal orientation as aforesaid, the pivot guides and the pivot mounts being constructed such that the pivot mounts disengage from the generally vertical engagement surfaces as the shredder mechanism housing is moved from the generally vertical orientation to the generally horizontal orientation. 7. A shredder according to claim 3, wherein the handle is provided on a front portion of the shredder housing. 8. A shredder according to claim 7, wherein the handle has a pair of spaced apart connector portions extending from the shredder housing and a hand grip portion extending between the connector portions in spaced apart relation from the shredder housing. 9. A shredder according to claim 4, wherein the handle is provided on a front portion of the shredder housing. 10. A shredder according to claim 9, wherein the handle has a pair of spaced apart connector portions extending from the shredder housing and a hand grip portion extending between the connector portions in spaced apart relation from the shredder housing. 11. A shredder according to claim 5, wherein the handle is provided on a front portion of the shredder housing. 12. A shredder according to claim 11, wherein the handle has a pair of spaced apart connector portions extending from the shredder housing and a hand grip portion extending between the connector portions in spaced apart relation from the shredder housing. 13. A shredder according to claim 6, wherein the handle is provided on a front portion of the shredder housing. 14. A shredder according to claim 13, wherein the handle has a pair of spaced apart connector portions extending from the shredder housing and a hand grip portion extending between the connector portions in spaced apart relation from the shredder housing. 15. A shredder according to claim 2, wherein the seat is constructed to be removably mounted on an upper portion of a container having an upwardly facing opening so that the articles being shredded and discharged from the cutter elements are discharged into the container. 16. A shredder according to claim 2, further comprising a container, wherein the seat is provided by an upper peripheral edge of the container so that the articles being shredded and discharged from the cutter elements are discharged into the container. 17. A shredder according to claim 15, wherein the shredder housing includes a waste opening spaced apart from the shredder mechanism that faces into the container when the seat is removably mounted thereon and the shredder housing is in the generally horizontal orientation for enabling articles to be discarded into the container without passing through the shredder mechanism. 18. A shredder according to claim 17, wherein the waste opening in the shredder housing is defined at least in part by a handle provided on the shredder housing, the handle being constructed to be manually grasped for moving the shredder housing between the generally horizontal and generally vertical orientations on the seat and lifting and lowering the shredder housing off of and onto the seat. 19. A shredder according to claim 18, wherein the handle and the waste opening are provided on a front portion of the shredder housing. 20. A shredder according to claim 19, wherein the handle has a pair of spaced apart connector portions extending form the shredder housing and a hand grip portion extending between the connector portions in spaced apart relation from the shredder housing, the hand grip portion and the connector portions defining part of the waste opening. 21. A shredder according to claim 16, wherein the shredder housing includes a waste opening spaced apart from the shredder mechanism that faces into the container when the shredder mechanism is in the generally horizontal orientation for enabling articles to be discarded into the container without passing through the shredder mechanism. 22. A shredder according to claim 21, wherein the waste opening in the shredder housing is defined at least in part by a handle provided on the shredder housing, the handle being constructed to be manually grasped for moving the shredder housing between the generally horizontal and generally vertical orientations on the seat and lifting and lowering the shredder housing off of and onto the seat. 23. A shredder according to claim 22, wherein the handle and the waste opening are provided on a front portion of the shredder housing. 24. A shredder according to claim 23, wherein the handle has a pair of spaced apart connector portions extending from the shredder housing and a hand grip portion extending between the connector portions in spaced apart relation from the shredder housing, the hand grip portion and the connector portions defining part of the waste opening. 25. A shredder comprising: a seat; a shredder housing, the shredder housing being constructed to be removably mounted to the seat; a shredder mechanism including a motor and cutter elements, the shredder mechanism enabling articles to be shredded to be fed into the cutter elements and the motor being operable to drive the cutter elements so that the cutter elements shred the articles fed therein, the shredder mechanism being mounted in the shredder housing; the shredder housing including a waste opening spaced apart from the shredder mechanism for enabling articles to be discarded through the waste opening without passing through the shredder mechanism; and a handle connected to the shredder housing for facilitating removal of the shredder housing from the seat, the handle defining at least a portion of the waste opening. 26. | FIELD OF THE INVENTION The present invention relates to shredders for destroying articles, such as documents, CDs, etc. BACKGROUND OF THE INVENTION Shredders are well known devices for destroying articles, such as documents, CDs, floppy disks, etc. Typically, users purchase shredders to destroy sensitive articles, such as credit card statements with account information, documents containing company trade secrets, etc. A common type of shredder has a shredder mechanism contained within a housing that is removably mounted atop a container. The shredder mechanism typically has a series of cutter elements that shred articles fed therein and discharge the shredded articles downwardly into the container. When it is desired to service the shredder mechanism, or clear jammed articles from the cutter elements, the housing is typically lifted off the container to provide access to the underside of the shredder mechanism or for emptying the container. Typically, this is done by lifting the housing vertically off the container with two hands. The present invention endeavors to provide a simpler and more ergonomically efficient approach to removing the shredder housing from its operative position on a container. SUMMARY OF THE INVENTION One aspect of the present invention provides a shredder comprising a seat, a shredder housing, and a shredder mechanism including a motor and cutter elements. The shredder mechanism enables articles to be shredded to be fed into the cutter elements and the motor is operable to drive the cutter elements so that the cutter elements shred the articles fed therein. The seat has a pivot guide and the shredder housing includes a pivot mount. The shredder housing is constructed to be removably mounted to the seat in a generally horizontal orientation with the pivot mount removably engaged with the pivot guide. The pivot mount and the pivot guide are constructed to pivotally mount the shredder housing for pivotal movement between the generally horizontal orientation and a generally vertical orientation. Another aspect of the invention provides a shredder with a waste opening feature. The shredder of this aspect of the invention comprises a seat, a shredder housing, and a shredder mechanism including a motor and cutter elements. The shredder mechanism enables articles to be shredded to be fed into the cutter elements and the motor is operable to shred the articles fed therein. The shredder mechanism is mounted in the shredder housing. The shredder housing is constructed to be removably mounted to the seat. The shredder housing includes a waste opening spaced apart from the shredder mechanism for enabling articles to be discarded through the waste opening without passing through the shredder mechanism. A handle is coupled to the shredder housing and facilitates removal of the shredder housing from the seat. The handle defines at least a portion of the waste opening. Other objects, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a shredder constructed in accordance with an embodiment of the present invention; FIG. 2 is an exploded perspective view of the shredder of FIG. 1; FIG. 3 is a perspective view of the shredder of FIG. 1, showing the shredder being pivoted from its generally horizontal use position; FIG. 4 is a perspective view of the shredder of FIG. 1, showing the shredder in its generally vertical orientation; FIG. 5 is a perspective view of the shredder of FIG. 1, showing the shredder being lifted off of the container; FIG. 6 is a cross-sectional view showing the pivot mount and the pivot guide of the shredder of FIG. 1 in its generally horizontal orientation; FIG. 7 is a cross-sectional view similar to FIG. 6 with the shredder in its generally vertical position; and FIG. 8 is a perspective view of a shaft and cutter element used in the shredder. DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS FIGS. 1-8 illustrate an embodiment of a shredder constructed in accordance with one embodiment of the present invention. The shredder is generally indicated at 10. The shredder 10 sits atop a waste container, generally indicated at 12, which is formed of molded plastic or any other material. The shredder 10 illustrated is designed specifically for use with the container 12, as the shredder housing 14 sits on the upper periphery of the waste container 12 in a nested relation, which will be discussed in further detail below. Generally speaking, the shredder 10 may have any suitable construction or configuration and the illustrated embodiment is not intended to be limiting in any way. The shredder 10 includes a shredder mechanism 16 including an electrically powered motor 18 and a plurality of cutter elements 20. The cutter elements 20 are mounted on a pair of parallel rotating shafts 22, one of which is shown in FIG. 8. The motor 18 operates using electrical power to rotatably drive the shafts 22 and the cutter elements 20 through a conventional transmission 23 so that the cutter elements 20 shred articles fed therein. The shredder mechanism 16 may also include a sub-frame 21 for mounting the shafts 22, the motor 18 and the transmission 23. The operation and construction of such a shredder mechanism 16 are well known and need not be described herein in detail. Generally, any suitable shredder mechanism 16 known in the art or developed hereafter may be used. The shredder 10 also includes the shredder housing 14, mentioned above. The shredder housing 14 includes top wall 24 that sits atop the container 12. The top wall 14 is molded from plastic and an opening 26 is located at a front portion thereof. The opening 26 is formed in part by a downwardly depending generally U-shaped member 28. The U-shaped member 28 has a pair of spaced apart connector portions 27 on opposing sides thereof and a hand grip portion 28 extending between the connector portions 27 in spaced apart relation from the housing 14. The opening 26 allows waste to be discarded into the container 12 without being passed through the shredder mechanism 16, and the member 28 may act as a handle for carrying the shredder 10 separate from the container 12. As an optional feature, this opening 26 may be provided with a lid, such as a pivoting lid, that opens and closes the opening 26. However, this opening in general is optional and may be omitted entirely. Moreover, the shredder housing 14 and its top wall 24 may have any suitable construction or configuration. The shredder housing 14 also includes a bottom receptacle 30 having a bottom wall, four side walls and an open top. The shredder mechanism 16 is received therein, and the receptacle 30 is affixed to the underside of the top wall 24 by fasteners. The receptacle 30 has an opening 32 in its bottom wall through which the shredder mechanism 16 discharges shredded articles into the container 12. For more details on this structure, reference may be made to the U.S. Patent Application for which a serial number has not been assigned, by Taihoon K. Matlin et al., entitled Shredder with Lock for On/Off Switch filed Apr. 2, 2004, the entirety of which is hereby incorporated into the present application by reference. The top wall 24 has a generally laterally extending opening 36 extending generally parallel and above the cutter elements 20. The opening 36, often referred to as a throat, enables the articles being shredded to be fed into the cutter elements 20. As can be appreciated, the opening 36 is relatively narrow, which is desirable for preventing overly thick items, such as large stacks of documents, from being fed into cutter elements 20, which could lead to jamming. The opening 36 may have any configuration. The top wall 24 also has a switch recess 38 with an opening therethrough. An on/off switch 42 includes a switch module (not shown) mounted to the top wall 24 underneath the recess 38 by fasteners, and a manually engageable portion 46 that moves laterally within the recess 38. The switch module has a movable element (not shown) that connects to the manually engageable portion 46 through the opening 40. This enables movement of the manually engageable portion 46 to move the switch module between its states. In the illustrated embodiment, the switch module connects the motor 18 to the power supply (not shown). Typically, the power supply will be a standard power cord 44 with a plug 48 on its end that plugs into a standard AC outlet. The switch 42 is movable between an on position and an off position by moving the portion 46 laterally within the recess 38. In the on position, contacts in the switch module are closed by movement of the manually engageable portion 46 and the movable element to enable a delivery of electrical power to the motor 18. In the off position, contacts in the switch module are opened to disable the delivery of electric power to the motor 18. As an option, the switch 42 may also have a reverse position wherein contacts are closed to enable delivery of electrical power to operate the motor 18 in a reverse manner. This would be done by using a reversible motor and applying a current that is of a reverse polarity relative to the on position. The capability to operate the motor 18 in a reversing manner is desirable to move the cutter elements 20 in a reversing direction for clearing jams. In the illustrated embodiment, in the off position the manually engageable portion 46 and the movable element would be located generally in the center of the recess 38, and the on and reverse positions would be on opposing lateral sides of the off position. Generally, the construction and operation of the switch 42 for controlling the motor 42 are well known and any construction for such a switch 42 may be used. The top cover 24 also includes another recess 50 associated with a switch lock 52. The switch lock 52 includes a manually engageable portion 54 that is movable by a user's hand and a locking portion (not shown). The manually engageable portion 54 is seated in the recess 50 and the locking portion is located beneath the top wall 24. The locking portion is integrally formed as a plastic piece with the manually engageable portion 54 and extends beneath the top wall 24 via an opening formed in the recess 50. The switch lock 52 causes the switch 42 to move from either its on position or reverse position to its off position by a camming action as the switch lock 52 is moved from a releasing position to a locking position. In the releasing position, the locking portion is disengaged from the movable element of the switch 42, thus enabling the switch 42 to be moved between its on, off, and reverse positions. In the locking position, the movable element of the switch 42 is restrained in its off position against movement to either its on or reverse position by the locking portion of the switch lock 52. Preferably, but not necessarily, the manually engageable portion 54 of the switch lock 52 has an upwardly extending projection 56 for facilitating movement of the switch lock 52 between the locking and releasing positions. One advantage of the switch lock 52 is that, by holding the switch 42 in the off position, to activate the shredder mechanism 16 the switch lock 52 must first be moved to its releasing position, and then the switch 42 is moved to its on or reverse position. This reduces the likelihood of the shredder mechanism 16 being activated unintentionally. The construction and operation of the switch lock 52 and its relationship with the switch 42 is described in further detail in the U.S. Patent Application of Matlin et al. mentioned above. In the illustrated embodiment, the shredder housing 14 is designed specifically for use with the container 12 and it is intended to sell them together. The upper peripheral edge 60 of the container 12 defines an upwardly facing opening 62, and provides a seat 61 on which the shredder 10 is removably mounted. The seat 61 includes a pair of pivot guides 64 provided on opposing lateral sides thereof. The pivot guides 64 include upwardly facing recesses 66 that are defined by walls extending laterally outwardly from the upper edge 60 of the container 12. The walls defining the recesses 66 are molded integrally from plastic with the container 12, but may be provided as separate structures and formed from any other material. At the bottom of each recess 66 is provided a step down or ledge providing a generally vertical engagement surface 68. This step down or ledge is created by two sections of the recesses 66 being provided with different radii. The shredder housing 14 has a pair of pivot mounts 70 provided on opposing lateral sides thereof. Each of the pivot mounts 70 includes a wall 72 extending laterally outwardly that has a generally semi-circular configuration. The walls 72 are molded integrally from plastic with the housing 14, but may be provided as separate structures and formed from any other material. The configuration generally corresponds to the configuration of the recesses 66 on the container 12. During normal usage, the shredder 10 is removably mounted in a generally horizontal orientation on the upper peripheral edge 60 of the container 12 with the pivot mounts 70, particularly the semi-circular walls 72, received in the upwardly facing recesses 66 of the pivot guides 64. This is shown best in FIGS. 4, 6 and 7. To remove the shredder 10 from the container 12 for purposes of emptying the container 12 or clearing a jam from the underside of the shredder mechanism 16, the user can manually grab the handle 28 with his/her hand as shown in FIG. 3. Then the user can pivot the shredder 10 by the handle 28 up to the generally vertical position shown in FIG. 4. Next, the user can lift the shredder 10 generally vertically off the upper peripheral edge 62 of the container 12, as shown in FIG. 5. As can be seen in FIG. 7, when the shredder 10 is in its generally vertical position, surfaces 74 at the upper edges of the walls 72 engage the engagement surfaces 68 on the recesses 66. This engagement provides support to the shredder 10 against movement thereof back towards the generally horizontal orientation. This is advantageous because it allows the user to easily lift the shredder 10 up off the seat 61. Also, when placing the shredder 10 back on the seat 61 (which is done by reversing the removal steps), the engagement between the surfaces 74 at the upper edges of the walls 72 and the engagement surfaces 68 help ensure proper location of the shredder 10. It should be noted that the pivot guides 64 and the pivot mounts 70 may have any suitable construction or configuration and the example illustrated is in no way intended to be limiting. In an alternative embodiment, the seat 61 could be a structure that is separate from the container 12 and could be designed for use with other types of containers. For example, the seat could be constructed so as to be adjustable for purposes of being removably mounted on a wide variety of containers. This would allow an end user to “retrofit” any type of container, such as a typical wastebasket, into a shredder container with the seat supporting the shredder 10. In this exemplary alternative, the shredder 10 and seat cold be sold together without the container, thus reducing packaging size and space. As such, the term seat is used herein to refer to any structure to which a shredder is mounted, and it is not limited to a seat that is integrally formed with a container as illustrated. The foregoing illustrated embodiment has been provided to illustrate the structural and functional principles of the present invention and is not intended to be limiting. To the contrary, the present invention is intended to encompass all modifications, alterations and substitutions within the spirit and scope of the appended claims. | <SOH> BACKGROUND OF THE INVENTION <EOH>Shredders are well known devices for destroying articles, such as documents, CDs, floppy disks, etc. Typically, users purchase shredders to destroy sensitive articles, such as credit card statements with account information, documents containing company trade secrets, etc. A common type of shredder has a shredder mechanism contained within a housing that is removably mounted atop a container. The shredder mechanism typically has a series of cutter elements that shred articles fed therein and discharge the shredded articles downwardly into the container. When it is desired to service the shredder mechanism, or clear jammed articles from the cutter elements, the housing is typically lifted off the container to provide access to the underside of the shredder mechanism or for emptying the container. Typically, this is done by lifting the housing vertically off the container with two hands. The present invention endeavors to provide a simpler and more ergonomically efficient approach to removing the shredder housing from its operative position on a container. | <SOH> SUMMARY OF THE INVENTION <EOH>One aspect of the present invention provides a shredder comprising a seat, a shredder housing, and a shredder mechanism including a motor and cutter elements. The shredder mechanism enables articles to be shredded to be fed into the cutter elements and the motor is operable to drive the cutter elements so that the cutter elements shred the articles fed therein. The seat has a pivot guide and the shredder housing includes a pivot mount. The shredder housing is constructed to be removably mounted to the seat in a generally horizontal orientation with the pivot mount removably engaged with the pivot guide. The pivot mount and the pivot guide are constructed to pivotally mount the shredder housing for pivotal movement between the generally horizontal orientation and a generally vertical orientation. Another aspect of the invention provides a shredder with a waste opening feature. The shredder of this aspect of the invention comprises a seat, a shredder housing, and a shredder mechanism including a motor and cutter elements. The shredder mechanism enables articles to be shredded to be fed into the cutter elements and the motor is operable to shred the articles fed therein. The shredder mechanism is mounted in the shredder housing. The shredder housing is constructed to be removably mounted to the seat. The shredder housing includes a waste opening spaced apart from the shredder mechanism for enabling articles to be discarded through the waste opening without passing through the shredder mechanism. A handle is coupled to the shredder housing and facilitates removal of the shredder housing from the seat. The handle defines at least a portion of the waste opening. Other objects, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. | 20040421 | 20060411 | 20051027 | 75483.0 | 1 | ROSENBAUM, MARK | SHREDDER WITH PIVOTING HOUSING FOR THE SHREDDER MECHANISM | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,828,350 | ACCEPTED | Framing system | A framed shear wall has a pair of crossed tension straps passing through the studs that make up the shear wall. The straps are preferably rods and are preferably attached to upstanding plates installed at the corners of the wall. Each of two straps is preferably attached to an opposite side of the upstanding plate such that the straps do not interfere with each other where the straps cross. The straps preferably include threaded ends and the upstanding plates preferably have threaded receptacles sized to accept the threaded ends of the straps such that the straps can be tensioned before and/or after installation. In one embodiment, the upstanding plates are bolted through a bottom surface of the wall into a threaded anchor plate at floor level, and the threaded anchor plate is attached to a top of a wall on a floor below. | 1. A shear wall comprising: an upper channel; a lower channel; a plurality of spaced-apart studs connected between the upper channel and the lower channel, the plurality of studs including a first stud connected to the upper channel near a first end of the upper channel to form a first corner and connected to the lower channel near a first end of the lower channel to form a second corner, a second stud connected near a second end of the upper channel to form a third corner and near a second end of the lower channel to form a fourth corner, and a plurality of interior studs spaced between the first and second studs, each of the interior studs having at least two holes formed therein and having a front face and a rear face; a first rod connected to the wall near the first and fourth corners; and a second rod connected to the wall near the second and third corners; wherein each of the first and second rods pass through one of the two holes in each of the interior studs such that neither the first rod nor the second rod extend past the front face or the rear face of any interior stud. 2. The shear wall of claim 1, wherein the studs and channels are made from steel. 3. The shear wall of claim 1, wherein each end of the first and second rods is attached to an upstanding plate at each of the four corners of the wall. 4. The shear wall of claim 3, wherein each upstanding plate is integrally formed with a base plate to form a T plate. 5. The shear wall of claim 3, wherein each end of the rods is threaded, and wherein a first end of each rod has a right hand thread, a second end of each rod has a left hand thread, and wherein each upstanding plate has a block attached to it, the block having a hole threaded to mate with a respective threaded end of a rod. 6. The shear wall of claim 5, wherein blocks corresponding to the first rod are attached to a first side of a respective upstanding plate and blocks corresponding to the second rod are attached to an opposite side of a respective upstanding plate such that the first and second rods do not interfere with each other where they cross. 7. The shear wall of claim 1, further comprising a first anchor plate connected to a top of the wall near the first corner and a second anchor plate connected to the top of the wall near the third corner. 8. The shear wall of claim 7, wherein each of the anchor plates has a plurality of threaded holes formed therein. 9. The shear wall of claim 8, wherein the threaded holes formed in the anchor plate are formed by welding a threaded nut to the anchor plate. 10. The shear wall of claim 7, further comprising a first hollow spacer connected between the wall and an anchor plate near the first corner and a second hollow spacer connected between the wall and an anchor plate near the second corner. 11. The shear wall of claim 1, wherein at least one of the rods includes a turnbuckle, whereby the rod may be tensioned by adjusting the turnbuckle. 12. A light gauge steel shear wall comprising: an upper channel; a lower channel; a plurality of spaced-apart studs connected between the upper channel and the lower channel, the plurality of studs including a first set of ganged studs connected at one end to a first end of the upper channel to form a first corner and connected at an other end to a first end of the lower channel to form a second corner, a second set of ganged studs connected at one end to a second end of the upper channel to form a third corner and connected at an other end to a second end of the lower channel to form a fourth corner, and a plurality of interior studs in a spaced apart relationship between the first and second studs, each of the interior studs having two holes formed therein and having a front face and a rear face; a T plate near each of the first, second, third and fourth corners, each of the T plates comprising integrally formed base plates and upstanding plates, the base plates being positioned inside respective channels, each of the upstanding plates including a block having a threaded hole, each threaded hole having a thread in a direction opposite of a direction of a thread in a threaded hole in a diagonally opposite corner, threaded blocks in diagonally opposite corners being positioned on a same side of respective upstanding plates, the same side being opposite a side of the upstanding plate on which blocks are attached in other corners; a first rod with threaded ends mated to blocks in the first and fourth corners; and a second rod with threaded ends mated to blocks in the second and third corners; wherein each of the first and second rods pass through one of the two holes in each of the interior studs such that neither the first rod nor the second rod extend past the front face or the rear face of any interior stud. 13. The shear wall of claim 12, further comprising a hollow rectangular member welded to a top surface of the upper channel; a first spacer attached to the hollow rectangular member at the first corner; a second spacer attached to the hollow rectangular member at the third corner; a first anchor plate attached to the first spacer; and a second anchor plate attached to the second spacer; wherein each of the anchor plates has a plurality of holes formed therein and a plurality of nuts attached thereto, one of the plurality of nuts being attached to the anchor plate at a location corresponding to one of the plurality of holes such that a bolt may pass through the hole to mate with the nut. 14. A method of constructing a structure comprising the steps of: installing a floor over a first light gauge framed shear wall, the shear wall having an upper surface having a first end and a second end, each of the first and second ends having a hollow spacer attached thereto, each of the hollow spacers having an anchor plate attached thereto, each of the anchor plates having a plurality of threaded holes positioned such that nuts mating with the threaded holes pass through the threaded holes into an inside of the spacer, the floor being installed such that it has a top surface even with a top of the anchor plate; and installing a second light gauge framed shear wall over the top surface of the floor, the second light gauge framed shear wall being bolted to the anchor plate. 15. The method of claim 14, wherein each of the shear walls includes a pair of rods having threaded ends, a first end of each rod having a thread with a direction opposite a direction of a thread on a second end of the same rod, the ends of each of the rods being mated to matching threaded holes in diagonally opposite corners of the wall; further comprising the step of turning each of the first and second rods in a direction that places the rods under increased tension. 16. The method of claim 15, wherein the turning step is performed on the second shear wall after the floor is installed. 17. The method of claim 14, wherein the floor is formed of concrete and further including the step of screeding the concrete to a top of the anchor plate. 18. A method for installing a shear wall comprising the steps of: attaching a shear wall to a floor, the shear wall including a plurality of vertically oriented studs, the shear wall having four corners, diagonally opposite corners being connected by first and second rods, each of the first and second rods passing through a hole in each of the studs such that neither the first rod nor the second rod extends past an exterior or interior face of the studs, each of the first and second rods having a first end and a second end, the first end being threaded in a first direction and the second end being threaded in a second direction opposite the first direction; and rotating the rods to place the rods under tension. 19. The method of claim 18, further comprising the step of attaching a material over at least one of the interior and the exterior faces of the studs. 20. The method of claim 19, wherein the material is a panel material selected from a group consisting of drywall and plywood. | BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to framing systems generally, and more particularly to light gauge framing systems. 2. Discussion of the Background Light gauge framing, especially light gauge steel framing, is becoming an increasingly popular alternative to wood framing in both residential and commercial construction. Structures built with light gauge framing, like other structures, must resist natural forces such as windstorms and earthquakes. “Shear elements” is the name given to elements of the structure that resist these forces. In light gauge framing, the shear elements are typically shear walls. Shear walls are typically constructed by either 1) applying a strong panel product such as plywood on the outside of a wall framed with light gauge elements, or 2) applying a tension strap to the outside of such a light gauge framed wall (as used herein, “framed wall” refers to a wall constructed with spaced-apart studs). The requirement for a strong panel material such as plywood in the first method is undesirable because these panel materials cost more than alternative, lower strength panel materials. The second method of applying tension straps to the outside of the framed wall is undesirable for at least two reasons. First, applying tension straps on the exterior (either the inward or outward facing side) of a framed wall interferes with materials (e.g., drywall or plywood) placed over the straps. Second, installing the straps can be problematic. On the one hand, if the straps are installed before the wall is in place, the wall cannot be adjusted to account for on-site conditions. Alternatively, if the straps are installed after the wall is in place, the straps are often simply screwed or tack-welded in place without being under tension. This results in a fairly large displacement before the straps have any effect, thereby decreasing the effectiveness of the straps. What is needed is an improved method for constructing a light gauge shear wall that can be easily manufactured and installed in a structure and that does not interfere with subsequently installed construction materials. SUMMARY The present invention meets the aforementioned need to a great extent by providing a framed shear wall having a pair of crossed tension straps passing through the studs that make up the shear wall. The straps are preferably rods or cables and are preferably attached to upstanding plates installed at the corners of the wall. In highly preferred embodiments, each of two straps is attached to an opposite side of the upstanding plate such that the straps do not interfere with each other (i.e., one strap does not cause a deflection in the other strap) where the straps cross. The straps preferably include threaded ends and the upstanding plates preferably have threaded receptacles sized to accept the threaded ends of the straps such that the straps can be tensioned before and/or after installation. In one embodiment of the invention, the upstanding plates are bolted through a bottom surface of the wall into a threaded anchor plate at floor level. Preferably, the threaded anchor plate is welded to a top of a wall on a floor below. In highly preferred embodiments, the threaded plate is welded to the top of the wall on the floor below before the wall below is installed, and flooring materials (e.g., concrete) are installed around the threaded plate. In this way, a wall above such a floor can be installed by simply bolting the wall to the threaded plate. BRIEF DESCRIPTION OF THE DRAWINGS A more complete appreciation of the invention and many of the attendant features and advantages thereof will be readily obtained as the same become better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: FIG. 1 is a perspective view of two connected shear wall according to a preferred embodiment of the invention. FIG. 2 is a side view of the shear walls of FIG. 1. FIG. 3 is a perspective view of a corner interconnection between the shear walls of FIGS. 1 and 2. FIG. 4 is a perspective exploded view of the corner interconnection of FIG. 3. FIG. 5 is a side view of a T plate of one of the corners of the walls of FIGS. 1-4. FIG. 6 is a bottom view of the T plate of FIG. 5. FIG. 7 is a side view of the corner interconnection of FIG. 3. DETAILED DESCRIPTION The present invention will be discussed with reference to preferred embodiments of light gauge framed shear walls. Specific details are set forth in order to provide a thorough understanding of the present invention. The preferred embodiments discussed herein should not be understood to limit the invention. Furthermore, for ease of understanding, certain method steps are delineated as separate steps; however, these steps should not be construed as necessarily distinct nor order dependent in their performance. FIG. 1 is a perspective view and FIG. 2 is a side view of two attached shear walls 100 according to a preferred embodiment of the present invention. Each of the shear walls 100 comprises a plurality of vertically oriented, spaced-apart studs 110. Three studs 110 are ganged together at the sides of each of the walls 100 for added strength. The studs 110 are connected by a bottom channel 130 and a top channel 140. A hollow rectangular member 150 is installed on the top face of the top channel 150 opposite the side of the channel 150 that accepts the studs 110. Each of the walls 110 also includes two crossed rods 120 attached to upstanding plates 160 on opposite corners of the wall 100. The crossed rods 120 provide shear strength to the walls 100 and perform the function of the panel or straps in conventional shear walls. The rods 120 pass through holes in each of the studs 110 such that the rods are positioned entirely in the interior of the walls 100 such that no portion of the rods 110 extend past either the front or rear faces of the studs 110 or channels 130, 140. This allows materials such as drywall or paneling to be attached to the walls 100 without interference from the rods 120. A perspective view of an upper corner 101 and a lower corner 102 of the connected walls 100 of FIGS. 1 and 2 is illustrated in FIG. 3, and an exploded perspective view of these corners 101, 102 is illustrated in FIG. 4. The upper corner 101 is reinforced by a T plate 160 formed by a base plate 162 and an upstanding plate 161. The base plate 162 of the T plate 160 is positioned in the channel 140. A face plate 170 is preferably welded to an interior face 110a of the innermost stud 110, with the upper surface 170a of the face plate 170 welded to the upper surface 140a of the channel 140. The interior edge 161a of the upstanding plate 161 and the interior edge 162a of the base plate 162 are preferably welded to the face plate 170, with the base plate 162 also welded to the top surface 140a of the channel 140. The base plate 162 of the upper corner 101 is shown with a plurality of holes 163. These holes are not necessary when the T plate 160 is installed in an upper corner 101 (the holes 163 are necessary when the T plate 160 is used in a lower corner as will be discussed below) and thus may be omitted if desired. In preferred embodiments, the T plate 160 and the face plate 170 are welded in the corner 101 prior to installation and preferably at the factory. The upstanding plate 161 of the T plate 160 also includes a block 164 with a female threaded hole 165 sized to accept a threaded end 121 of rod 120. Opposite ends of any rod 120 are threaded in the opposite directions (i.e., one end is right-hand threaded and the opposite end is left-hand threaded) and blocks 164 in corresponding corners are threaded to match the end 121 of the rods 120. This is done so that when the rod is rotated, the blocks 164 on opposite ends of the rod 120 are either drawn in to increase tension on the rod 120 or pushed outward to release tension on the rod 120 depending on the direction in which the rod 120 is rotated. The blocks 164 are also preferably welded to the upstanding plate 160 in both the upper and lower corners 101, 102 prior to installation and more preferably at the factory. A rectangular member 150 is preferably welded to the top of the upper channel 140. The rectangular member 150 provides increased rigidity to the top of upper channel 140, which is especially desirable where a floor such as a concrete floor will be cast in place on top of the lower wall 110. The rectangular member 150 is also preferably welded to the upper channel 140 prior to installation and preferably at the factory. The upper and lower corners 101, 102 are separated by a rectangular spacer 180 with a width W1 sized to match a width W2 of the rectangular member 150. The height H of the spacer 180 is chosen to match a thickness of a floor to be installed between the walls 100. The floor may be any material, and is most often concrete. The spacer 180 is also preferably attached to rectangular member 150 prior to installation and preferably at the factory. An anchor plate 132 is attached to the top of the spacer 180. A side view of the anchor plate 132 and a bottom view of the anchor plate 132 are shown in FIGS. 5 and 6, respectively. The anchor plate 132 includes four holes 134. Threaded nuts 133 aligned with each of the holes 131 are welded to a bottom surface 132a of the anchor plate 132. The holes 134 and nuts 133 are positioned such that they can be fitted inside the spacer 180. The anchor plate 132 is preferably welded to the spacer 180 before the wall 100 is installed, and more preferably still at the factory. Thus, in preferred embodiments, the a wall 110 leaves the factory with a rectangular member 150 welded to the top of channel 140 and with a T plate 160 with block 164, a face plate 170, a spacer 180 and an anchor plate 132 all welded in the positions described above at each of the upper corners 101 at the factory. The lower corner 102 of the wall 110 is also reinforced with a T plate 160 and a face plate 170 installed in the similar manner as the upper corner 101. That is, the base plate 162 of the T plate 160 is welded to the upper interior surface 130a of the lower channel 130 and to the face plate 170, and the face plate 170 is welded to an inside face 110a of an interior corner stud 110 and the interior upper surface 130a of the channel 130. Like the lower corner 101, the T plate 160 and the face plate 170 are preferably welded prior to installation of the wall 100 and more preferably at the factory. Unlike the T plate 160 in the upper corner 101, it is necessary for the T plate 160 in the lower corner 102 to have holes 163 formed in base plate 162. The lower channel 130 also has a plurality of holes 131 in positions corresponding to the holes 163 in the base plate 162. The threaded ends 121 of the rods 120 are also preferably inserted into the blocks 164 of the T plates 160 at the factory in both the upper corner 101 and the lower corner 102, although they are preferably not under tension. Alternatively, the rods 120 may be installed at the work site. Each of the interior studs 110 has two holes formed therein, one for each of the crossed rods 120 as shown in FIG. 1. The blocks 164 of T plates 160 are positioned on opposite sides of the upstanding plates 161 on T plates on opposite sides of the wall 100. That is, the blocks 164 on the upper left hand and lower right hand corners of a wall 100 are on the same side of their respective upstanding plates 161, and the upper right hand and lower left hand corners of the same wall 100 have their blocks 164 on the opposites sides of upstanding plate 161 as shown in FIGS. 3 and 4. In this fashion, the two rods 120 are in parallel spaced apart planes and do not cause any deflection in each other even though they are both within the interior of the wall 100. With each of the walls 100 configured in the preferred manner described above, installation is greatly simplified. When walls 100 on a lower floor have been installed, the spacers 180 and anchors 132 protrude above the rectangular member 150. Next, a floor is installed such that the top surface is at the height of the top of the anchor plate 132. When the floor is concrete, the concrete is simply screeded to the top of the anchor plate 132. Once the floor is installed, the walls corresponding to that floor are simply placed in the desired location and secured to the anchor plates 132 with a plurality (4 are used in preferred embodiments) of bolts 166. As shown in FIG. 7, the bolts 166 extend through holes 163 in the base plate 162, the holes 131 in the lower channel 130, the holes 133 in the anchor plate 132, and into the threaded nuts 133. The rods 120 are then adjusted to the desired tension and the walls 100 are then ready for drywall or other desired finishing materials. This allows for very fast construction as compared to other methods. In addition, the rods 120 are at tension and are contained within the interior of the walls 100 so as not to interfere with the installation of drywall, plywood or other materials attached to the exterior surfaces of the walls 100. Those of skill in the art will recognize that it is not necessary for the anchor plates 132 to be attached to walls on the floor below and that the anchor plates 132 can simply be attached to a floor below. Alternatively, the walls 100 may be attached to the floor without the use of anchor plates 132. For example, when the walls 100 are installed over wood flooring, screws may be used in place of the bolts 166. As another example, when the walls are installed over concrete floors, anchor upstanding sill bolts may be cast in place in the concrete floor in positions such that they correspond to the holes 163 in the base plate 162 of T plate 160 and the walls 100 may be secured in place using nuts threaded onto the sill bolts. It should also be noted that rods having turnbuckles are used rather than threaded rods and threaded mating blocks in some embodiments of the invention. This allows the rods (or cables) to be fixedly attached to the corners of the wall and be tensioned through adjustment of the turnbuckle. Obviously, numerous other modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The invention relates to framing systems generally, and more particularly to light gauge framing systems. 2. Discussion of the Background Light gauge framing, especially light gauge steel framing, is becoming an increasingly popular alternative to wood framing in both residential and commercial construction. Structures built with light gauge framing, like other structures, must resist natural forces such as windstorms and earthquakes. “Shear elements” is the name given to elements of the structure that resist these forces. In light gauge framing, the shear elements are typically shear walls. Shear walls are typically constructed by either 1) applying a strong panel product such as plywood on the outside of a wall framed with light gauge elements, or 2) applying a tension strap to the outside of such a light gauge framed wall (as used herein, “framed wall” refers to a wall constructed with spaced-apart studs). The requirement for a strong panel material such as plywood in the first method is undesirable because these panel materials cost more than alternative, lower strength panel materials. The second method of applying tension straps to the outside of the framed wall is undesirable for at least two reasons. First, applying tension straps on the exterior (either the inward or outward facing side) of a framed wall interferes with materials (e.g., drywall or plywood) placed over the straps. Second, installing the straps can be problematic. On the one hand, if the straps are installed before the wall is in place, the wall cannot be adjusted to account for on-site conditions. Alternatively, if the straps are installed after the wall is in place, the straps are often simply screwed or tack-welded in place without being under tension. This results in a fairly large displacement before the straps have any effect, thereby decreasing the effectiveness of the straps. What is needed is an improved method for constructing a light gauge shear wall that can be easily manufactured and installed in a structure and that does not interfere with subsequently installed construction materials. | <SOH> SUMMARY <EOH>The present invention meets the aforementioned need to a great extent by providing a framed shear wall having a pair of crossed tension straps passing through the studs that make up the shear wall. The straps are preferably rods or cables and are preferably attached to upstanding plates installed at the corners of the wall. In highly preferred embodiments, each of two straps is attached to an opposite side of the upstanding plate such that the straps do not interfere with each other (i.e., one strap does not cause a deflection in the other strap) where the straps cross. The straps preferably include threaded ends and the upstanding plates preferably have threaded receptacles sized to accept the threaded ends of the straps such that the straps can be tensioned before and/or after installation. In one embodiment of the invention, the upstanding plates are bolted through a bottom surface of the wall into a threaded anchor plate at floor level. Preferably, the threaded anchor plate is welded to a top of a wall on a floor below. In highly preferred embodiments, the threaded plate is welded to the top of the wall on the floor below before the wall below is installed, and flooring materials (e.g., concrete) are installed around the threaded plate. In this way, a wall above such a floor can be installed by simply bolting the wall to the threaded plate. | 20040421 | 20071127 | 20051027 | 92861.0 | 1 | CHAPMAN, JEANETTE E | FRAMING SYSTEM | UNDISCOUNTED | 0 | ACCEPTED | 2,004 |
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10,828,465 | ACCEPTED | Cluster-based operating system-agnostic virtual computing system | According to a disclosed embodiment of the invention, an improved cluster-based collection of computers (nodes) is realized using conventional computer hardware. Software is provided that enables at least one virtual machine to be presented to guest operating systems, wherein each node participating with the virtual machine has its own emulator or virtual machine monitor. VM memory coherency and I/O coherency are provided by hooks, which result in the manipulation of internal processor structures. A private network provides communication among the nodes. | 1. A method for executing a software application in a plurality of computing nodes having node resources, wherein said nodes include a first node and a second node that intercommunicate over a network, and said nodes being operative to execute a virtual machine that runs under a guest operating system, comprising the steps of: running at least a first virtual machine implementer and a second virtual machine implementer on said first node and said second node, respectively; and sharing said virtual machine between said first virtual machine implementer and said second virtual machine implementer. 2. The method according to claim 1, further comprising the step of running said software application over said guest operating system, so that commands invoked by said software application are monitored or emulated by said first virtual machine implementer and said second virtual machine implementer on said first node and said second node, while said node resources of said first node and said second node are shared by communication over said network. 3. The method according to claim 1, wherein at least one of said first virtual machine implementer and said second virtual machine implementer is a virtual machine monitor. 4. The method according to claim 1, wherein at least one of said first virtual machine implementer and said second virtual machine implementer is an emulator. 5. The method according to claim 1, wherein at least said first node comprises a first virtual node comprising a first physical CPU of said first node and a second virtual node comprising a second physical CPU of said first node. 6. The method according to claim 1, wherein said virtual machine comprises a first virtual machine and a second virtual machine, wherein said first virtual machine and said second virtual machine have a plurality of virtual CPU's that are virtualized by said first virtual machine implementer based on a first physical CPU and said second virtual machine implementer based on a second physical CPU, respectively. 7. The method according to claim 6, and a first virtual node comprises said first physical CPU and said second physical CPU. 8. The method according to claim 7, wherein said first virtual machine implementer virtualizes at least one of said virtual CPU's of said first virtual machine based on said first physical CPU and virtualizes at least one of said virtual CPU's in said second virtual machine based on said second physical CPU. 9. The method according to claim 1, further comprising the steps of: providing a management system for said first virtual machine implementer and said second virtual machine implementer to control said first node and said second node, respectively, wherein said management system comprises a wrapper for receiving calls to a device driver from said first virtual machine implementer, said wrapper invoking said device driver according to a requirement of said first virtual machine implementer. 10. The method according to claim 9, further comprising the step of providing a virtual PCI controller for said management system to control a physical PCI controller in one of said nodes. 11. The method according to claim 9, further comprising the step of providing a virtual DMA controller for said management system to control a physical DMA controller in one of said nodes. 12. The method according to claim 11, further comprising the steps of: providing a virtual PCI controller to control a physical PCI controller in one of said nodes; and during a bootup phase of operation scanning a device list with said virtual PCI controller to identify devices having onboard DMA controllers. 13. The method according to claim 1, further comprising the steps of: with said virtual machine implementer maintaining mirrors of a memory used by said guest operating system in each of said nodes; write-invalidating at least a portion of a page of said memory in one of said nodes; and transferring a valid copy of said portion of said page to said one node from another of said nodes via said network. 14. A computer software product, comprising a computer-readable medium in which computer program instructions are stored, which instructions, when read by a computer, cause the computer to perform a method for executing a software application in a plurality of computing nodes having node resources, wherein said nodes include a first node and a second node that intercommunicate over a network, and said nodes being operative to execute a virtual machine that runs under a guest operating system, comprising the steps of: running at least a first virtual machine implementer and a second virtual machine implementer on said first node and said second node, respectively; and sharing said virtual machine between said first virtual machine implementer and said second virtual machine implementer. 15. The computer software product according to claim 14, wherein at least one of said first virtual machine implementer and said second virtual machine implementer is a virtual machine monitor. 16. The computer software product according to claim 14, wherein at least one of said first virtual machine implementer and said second virtual machine implementer is an emulator. 17. The computer software product according to claim 14, wherein at least said first node comprises a first virtual node comprising a first physical CPU of said first node and a second virtual node comprising a second physical CPU of said first node. 18. The computer software product according to claim 17, wherein said virtual machine comprises a first virtual machine and a second virtual machine, wherein said first virtual machine and said second virtual machine have a plurality of virtual CPU's that are virtualized by said first virtual machine implementer based on said first physical CPU and said second virtual machine implementer based on said second physical CPU, respectively. 19. The computer software product according to claim 18, wherein said plurality of virtual CPU's that are virtualized by said first virtual machine implementer based on said first physical CPU and said second virtual machine implementer based on said second physical CPU, respectively. 20. The computer software product according to claim 18, wherein said first virtual node comprises said first physical CPU and said second physical CPU. 21. The computer software product according to claim 20, wherein said first virtual machine implementer virtualizes at least one of said virtual CPU's of said first virtual machine based on said first physical CPU and virtualizes at least one of said virtual CPU's in said second virtual machine based on said second physical CPU. 22. The computer software product according to claim 14, wherein said computer is further instructed to perform the step of running said software application over said guest operating system, so that commands invoked by said software application are received by said first virtual machine implementer and said second virtual machine implementer on said first node and said second node, while said node resources of said first node and said second node are shared by communication over said network. 23. The computer software product according to claim 14, further comprising the steps of: providing a management system for said first virtual machine implementer and said second virtual machine implementer to control said first node and said second node, respectively, wherein said management system comprises a wrapper for receiving calls to a device driver from said first virtual machine implementer and said second virtual machine implementer, said wrapper invoking said device driver according to a requirement of said first virtual machine implementer and said second virtual machine implementer. 24. The computer software product according to claim 23, further comprising the step of providing a virtual PCI controller for said management system to control a physical PCI controller in one of said nodes. 25. The computer software product according to claim 23, wherein said computer is further instructed to perform the step of providing a virtual DMA controller for said management system to control a physical DMA controller in one of said nodes. 26. The computer software product according to claim 25, wherein said computer is further instructed to perform the steps of: providing a virtual PCI controller to control a physical PCI controller in one of said nodes; and during a bootup phase of operation scanning a device list with said virtual PCI controller to identify devices having on-board DMA controllers. 27. The computer software product according to claim 14, wherein said computer is further instructed to perform the steps of: with said virtual machine implementer maintaining mirrors of a memory used by said guest operating system in each of said nodes; write-invalidating at least a portion of a page of said memory in one of said nodes; and transferring a valid copy of said portion of said page to said one node from another of said nodes via said network. 28. A computer system for executing a software application, comprising: a plurality of computing nodes, having node resources, said plurality of computing nodes comprising at least a first node and a second node; a network connected to said first node and said second node providing intercommunication therebetween; said first node and said second node being operative to execute a first virtual machine implementer and a second virtual machine implementer respectively, wherein a virtual machine is implemented concurrently by at least said first virtual machine implementer and said second virtual machine implementer; and said nodes being operative to execute a guest operating system over said virtual machine, wherein said software application executes over said guest operating system, so that commands invoked by said software application are received by said first virtual machine implementer and said second virtual machine implementer on said first node and said second node, while said node resources of said first node and said second node are shared by communication over said network. 29. The computer system according to claim 28, wherein said software application comprises a first software application and a second software application, said guest operating system comprises a first guest operating system and a second guest operating system, and said virtual machine comprises a first virtual machine and a second virtual machine, wherein said first software application and said first guest operating system are associated with said first virtual machine, and said second software application and said second guest operating system are associated with said second virtual machine. 30. The computer system according to claim 29, wherein one of said nodes has a first physical CPU and a second physical CPU, and said first virtual machine implementer virtualizes a first virtual CPU in said first virtual machine based on said first physical CPU and virtualizes a second virtual CPU in said second virtual machine based on said second physical CPU. 31. The computer system according to claim 28, wherein at least said first node comprises a first virtual node and a second virtual node. 32. The computer system according to claim 31, wherein said first node comprises a first processor and a second processor, a first I/O device and a second I/O device, wherein said first I/O device is assigned to said first processor, and said second I/O device is assigned to said second processor. 33. The computer system according to claim 28, further comprising a minimal operating system executing in each of said nodes to invoke said first virtual machine implementer and said second virtual machine implementer so that said first virtual machine implementer and said second virtual machine implementer control said nodes. 34. The computer system according to claim 28, further comprising a management system for said first virtual machine implementer and said second virtual machine implementer to control said first node and said second node, respectively, wherein said management system comprises a wrapper for receiving calls to a device driver from said first virtual machine implementer and said second virtual machine implementer, said wrapper invoking said device driver according to a requirement of said first virtual machine implementer and said second virtual machine implementer. 35. The computer system according to claim 34, further comprising a virtual PCI controller for said management system to control a physical PCI controller in one of said nodes. 36. The computer system according to claim 34, further comprising a virtual DMA controller for said management system to control a physical DMA controller in one of said nodes. 37. The computer system according to claim 28, further comprising a memory management system executing in at least one of said nodes that maintains mirrors of a memory used by said guest operating system in each of said nodes, wherein said memory management system write-invalidates at least a portion of a page of said memory in one of said nodes; and transfers a valid copy of said portion of said page to said one node from another of said nodes via said network. | CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of Provisional Application No. 60/494,392, filed Aug. 11, 2003, and of Provisional Application No. 60/499,646, filed Sep. 2, 2003. REFERENCE TO COMPUTER PROGRAM LISTING APPENDIX A computer program listing appendix is submitted herewith on one compact disc and one duplicate compact disc. The total number of compact discs including duplicates is two. The files on the compact disc are software object code and accompanying files for carrying out the invention. Their names, dates of creation, directory locations, and sizes in bytes are: .CONFIG of Aug. 27, 2003 located in the root folder and of length 28,335 bytes; BIOS.HEX of Aug. 27, 2003 located in the root folder and of length 241,664 bytes; SCMPVMMO.HEX of Aug. 27, 2003 located in the root folder and of length 201,603 bytes; SCMPVMMS.HEX of Aug. 27, 2003 located in the root folder and of length 20,119 bytes; and USERMODE.HEX of Aug. 27, 2003 located in the root folder and of length 37,170 bytes. The material on the compact discs is incorporated by reference herein. Installation and-execution instructions for the material on the compact disks are provided hereinbelow at Appendix 1. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to virtual computers. More particularly, this invention relates to improvements in a cluster-based symmetric multiprocessor. 2. Description of the Related Art The meanings of certain acronyms and terminology used herein are given in Table 1. TABLE 1 API Application programming interface CPU Central processing unit DMA Direct Memory Access - used by hardware devices, which are required to copy data to and from main system memory. DMA is used to relieve the CPU from waiting during memory accesses. False sharing In shared memory multiprocessors, when processors make references to different data items within the same block even though there is no actual dependence between the references. FSB Front-side bus NIC Network interface card NUMA Non-uniform memory access PCI Peripheral Component Interconnect - a standard for peripheral software and hardware interfaces. SMP Symmetric multiprocessor TLB Translation lookaside buffer VM Virtual machine VMM Virtual machine monitor A portion of the disclosure of this patent document, which includes a CD-ROM appendix, contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. The use of virtual computers (generally referred to as “virtual machines”) to enhance computing power has been known for several decades. For example, a classic system, VM, produced by IBM, enabled multiple users to concurrently use a single computer by running multiple copies of the operating system. Virtual computers have been realized on many different types of computer hardware platforms, including both single-processor and multi-processor units. Some virtual machine monitors are able to provide concurrent support for diverse operating systems. This requires the virtual machine monitor to present a virtual machine, that is a coherent view of the hardware, to each operating system. The above-noted VM system has evolved to the point where it is asserted that in one version, z/VM®, available from IBM, New Orchard Road, Armonk, N.Y., multiple operating systems can execute on a single server. Despite these achievements in virtual computing, practical issues remain. The currently dominant personal computer architecture, X86/IA32, which is used in the Intel Pentium™ and other Intel microprocessors, is not conducive to virtualization techniques for two reasons: (1) the instruction set of the CPU is not natively virtualizable; and (2) the X86/IA32 architecture has an open I/O architecture, which complicates the sharing of devices among different operating systems. This has been an impediment to continued advancements in the field. In general, it is inefficient, and probably impractical, for multiple operating systems to concurrently share common X86/IA32 hardware directly. System features of the X86/IA32 CPU are designed to be configured and used in a coordinated effort by only one operating system, e.g., paging and protection mechanisms, and segmentation. Limitations of the X86/IA32 architecture can be appreciated by a brief explanation of one known approach to virtual computers, in which a virtual machine monitor is used to provide a uniform execution environment within a computer. A virtual machine monitor is a software layer that in this approach is interposed between hardware of a single computer and one or more guest operating systems that support different applications. In this arrangement the virtual machine monitor interacts directly with the hardware, and exposes an expected interface to the guest operating systems. This interface includes normal hardware facilities, e.g., CPU, I/O, and memory. When virtualization is properly done, the guest operating systems are unaware that they are interacting with a virtual machine instead of directly with the hardware. For example, low level disk operations invoked by the operating systems, interaction with system timers, interrupts and exception handling are all managed transparently by the guest operating systems via the virtual machine monitor. To accomplish this, it is necessary that the virtual machine monitor be able to trap and execute certain hardware instructions dealing with the state of the processor. Significantly, the X86/IA32 employs four modes of protected operation, which are conveniently conceptualized as rings of protection, known as protection rings 0-3. Protection ring 0 is the most protected, and was designed for execution of the operating system kernel. Privileged instructions available only under protection ring 0 include instructions dealing with interrupt handling, and the modification of processor flags and page tables. Typical examples are store instructions for the global descriptor table (SGDT) and interrupt descriptor table (SIDT). Protection rings 1 and 2 were designed for other operating system services, e.g., device drivers. Protection ring 3, the least privileged, was intended for applications, and is also referred to as user mode. If it were possible to trap all of the privileged X86/IA32 instructions in user mode, it would be relatively straightforward for the virtual machine monitor to handle them using ordinary exception-handling techniques. Unfortunately, there are many privileged instructions of the X86/IA32 instruction set, which cannot be trapped under protection ring 3. Attempts to naively execute privileged instructions under protection ring 3 typically result in a general protection fault. Because of the importance of the X86/IA32 architecture, considerable effort has been devoted to overcoming its limitations with regard to virtualization. Virtual machines have been proposed to be implemented by software emulation of at least the privileged instructions of the X86/IA32 instruction set. Alternatively, binary translation techniques can be utilized in the emulator. Binary translation techniques in connection with a virtual machine monitor are disclosed in U.S. Pat. No. 6,397,242, the disclosure of which is incorporated herein by reference. Additionally or alternatively, combinations of direct execution and binary translation can be implemented. The open source Bochs IA-32 Emulator, downloadable via the Internet at the URL http://bochs.sourceforge.net/, is an example of a complete emulator. Another example is the SimOS environment, available via the Internet at the URL http://simos.stanford.edu/. The SimOS environment is adapted to the MIPS R4000 and R10000 and Digital Alpha processor families. Generally, the performance of emulators is relatively slow. Another known approach employs a hosted architecture. A virtual machine application uses a VM driver to load a virtual machine monitor at a privileged level. Typical of this approach are the disclosures of U.S. Pat. Nos. 6,075,938 and 6,496,847, which are incorporated herein by reference. The virtual machine monitor then uses the I/O services of a host operating system to accommodate user-level VM applications. Current examples of this approach include the VMware Workstation™, the VMware GSX Server™, both available from VMware, Inc., 3145 Porter Drive, Palo Alto, Calif. 94304, and the Connectix Virtual PC™, available from Microsoft Corporation, One Microsoft Way, Redmond, Wash. 98052-6399. Another example is the open source Plex86 Virtual Machine, available via the Internet at the URL http://plex86.sourceforge.net/. The hosted architecture is attractive due to its simplicity. However, it incurs a performance penalty because the virtual machine monitor must itself run as a scheduled application under the host operating system, and could even be swapped out. Furthermore, it requires emulators to be written and maintained for diverse I/O devices that are invoked by the virtual machine monitor. It is known in the art to use multiple processors in a single computer in order to enhance overall system performance. One known architecture is symmetric multiprocessing (SMP), in which application programs are processed by multiple processors that share a common operating system and memory. Typically, the processors share memory and the I/O bus or data path, and are controlled by a single instance of an operating system. In order to enhance performance, SMP systems may employ non-uniform memory access (NUMA), a method of configuring the microprocessors so that they can share memory locally. In a variation of multiprocessing systems, multiple relatively small computers, either uniprocessors or multiprocessors having relatively few processors, are linked together and coordinated to execute multiple applications, while serving one or more users. This arrangement is known as a cluster, or scaled-out arrangement. Some systems of this type can outperform corresponding SMP configurations. However, in the past it has been necessary that applications for cluster-based systems be specialized, so that they are cluster-aware. This has increased development expense, and in some cases, has impeded the use of standard commercial software on cluster-based systems. An unsuccessful attempt to implement a VM computing paradigm on cluster-based systems is disclosed in the document The Memory and Communication Subsystem of Virtual Machines for Cluster Computing, Shiliang Hu and Xidong Wang, January 2002 (Hu et al.), published on the Internet at the URL http://www.cs.wisc.edu/˜wxd/report/ece902.pdf. In this proposed arrangement, multiple SMP clusters of NUMA-like processors are monitored by virtual machine monitors. A cluster interconnect deals with message passing among the clusters. The system consists of multiple virtual machines that operate under a single operating system, and support parallel programming models. While a virtual computer built according to this paradigm would initially appear to be highly scalable, preliminary simulations of the communication and memory subsystems were discouraging. A further difficulty is posed by limitations of current operating systems, which are generally unaware of the locality of NUMA-type memory. According to Hu et al., the proposed paradigm could not be reduced to practice until substantial technological changes occur in the industry. Thus Hu et al. appears to have encountered a well-known difficulty: cluster machines generally, and NUMA machines in particular, can be scaled up successfully only if some way is found to ensure a high computation to communication ratio in regard to both data distribution and explicit communication among the clusters and processors. The most successful of the solutions noted above, in the case of the IBM z/VM product, have relied upon revisions and optimizations of the underlying computer hardware in order to overcome the issues encountered by Hu et al., and to increase performance generally, or have required kernel modifications of operating system software, in the case of the above-noted VMWare products. These approaches are costly in terms of product development, marketing, and maintenance, and often commercially impracticable, due to secrecy policies of operating system software vendors. SUMMARY OF THE INVENTION According to a disclosed embodiment of the invention, an improved cluster-based collection of computers (nodes) is realized using unmodified conventional computer hardware and unmodified operating system software. Software is provided that enable a virtual machine to be presented to a guest operating system, wherein each node participating with the virtual machine has its own emulator or virtual machine monitor. VM memory coherency and I/O coherency are provided by hooks, which result in the manipulation of internal processor structures. A private network provides communication among the nodes. The invention provides a method for executing a software application in a plurality of computing nodes has node resources, wherein the nodes include a first node and a second node that intercommunicate over a network, and the nodes is operative to execute a virtual machine that runs under a guest operating system. The method is carried out by running at least a first virtual machine implementer and a second virtual machine implementer on the first node and the second node, respectively, and sharing the virtual machine between the first virtual machine implementer and the second virtual machine implementer. An aspect of the method includes running the software application over the guest operating system, so that commands invoked by the software application are monitored or emulated by the first virtual machine implementer and by the second virtual machine implementer on the first node and the second node, while the node resources of the first node and the second node are shared by communication over the network. According to an additional aspect of the method, at least one of the first virtual machine implementer and the second virtual machine implementer is a virtual machine monitor. According to one aspect of the method, at least one of the first virtual machine implementer and the second virtual machine implementer is an emulator. According to still another aspect of the method, at least the first node has a first virtual node that includes a first physical CPU of the first node and has a second virtual node that includes a second physical CPU of the first node. According to another aspect of the method, there are a plurality of virtual machines including a first virtual machine and a second virtual machine, wherein the first virtual machine and the second virtual machine have a plurality of virtual CPU's that are virtualized by the first virtual machine implementer in the first node based on a first physical CPU and by the second virtual machine implementer in the second node based on a second physical CPU, respectively. According to yet another aspect of the method, and a first virtual node includes the first physical CPU and the second physical CPU. According to a further aspect of the method, the first virtual machine implementer virtualizes at least one of the virtual CPU's of the first virtual machine based on the first physical CPU and virtualizes at least one of the virtual CPU's in the second virtual machine based on the second physical CPU. Another aspect of the method includes providing a management system for the first virtual machine implementer and the second virtual machine implementer to control the first node and the second node, respectively, wherein the management system includes a wrapper for receiving calls to a device driver from the first virtual machine implementer, the wrapper invoking the device driver according to a requirement of the first virtual machine implementer. A further aspect of the method includes providing a virtual PCI controller for the management system to control a physical PCI controller in one of the nodes. Yet another aspect of the method includes providing a virtual DMA controller for the management system to control a physical DMA controller in one of the nodes. Still another aspect of the method includes providing a virtual PCI controller to control a physical PCI controller in one of the nodes, and during a bootup phase of operation scanning a device list with the virtual PCI controller to remap memory regions and resources and identify devices having on-board DMA controllers. In one aspect of the method the virtual machine implementer maintains mirrors of a memory used by the guest operating system in each of the nodes, the method further including write-invalidating at least a portion of a page of the memory in one of the nodes, and transferring a valid copy of the portion of the page to the one node from another of the nodes via the network. The invention provides a computer software product, including a computer-readable medium in which computer program instructions are stored, which instructions, when read by a computer, cause the computer to perform a method for executing a software application in a plurality of computing nodes has node resources, wherein the nodes include a first node and a second node that intercommunicate over a network, and the nodes is operative to execute a virtual machine that runs under a guest operating system. The method is carried out by running at least a first virtual machine implementer and a second virtual machine implementer on the first node and the second node, respectively, and sharing the virtual machine between the first virtual machine implementer and the second virtual machine implementer. The invention provides a computer system for executing a software application, including a plurality of computing nodes, the plurality of computing nodes including at least a first node and a second node, a network connected to the first node and the second node providing intercommunication therebetween, a first virtual machine implementer and a second virtual machine implementer executing on the first node and the second node, respectively. The system further includes a virtual machine implemented concurrently by at least the first virtual machine implementer and the second virtual machine implementer, and a guest operating system executing over the virtual machine, wherein the software application executes over the guest operating system, so that commands invoked by the software application are received by the first virtual machine implementer and the second virtual machine implementer on the first node and the second node, while the node resources of the first node and the second node are shared by communication over the network. BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the present invention, reference is made to the detailed description of the invention, by way of example, which is to be read in conjunction with the following drawings, wherein like elements are given like reference numerals, and wherein: FIG. 1 is a block diagram of a cluster-based virtual computing arrangement that is constructed and operative in accordance with a disclosed embodiment of the invention; FIG. 2 is a detailed block diagram of a virtual machine monitor that is constructed and operative in accordance with an alternate embodiment of the invention; FIG. 3 is a detailed block diagram of an alternate virtual machine monitor that is constructed and operative in accordance with an alternate embodiment of the invention; FIG. 4 is a block diagram of a cluster-based virtual computing arrangement employing multiprocessors and virtual nodes in which there are a plurality of virtual machine implementers per node that is constructed and operative in accordance with an alternate embodiment of the invention; FIG. 5 is a block diagram of a cluster-based virtual computing arrangement employing multiprocessors and virtual nodes having a plurality of virtual machine implementers per CPU that is constructed and operative in accordance with an alternate embodiment of the invention; and FIG. 6 is a block diagram of a cluster-based virtual computing arrangement that employs a virtual machine monitor having a management system, that is constructed and operative in accordance with an alternate embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent to one skilled in the art, however, that the present invention may be practiced without these specific details. In other instances well-known circuits, control logic, and the details of computer program instructions for conventional algorithms and processes have not been shown in detail in order not to unnecessarily obscure the present invention. Software programming code, which embodies aspects of the present invention, is typically maintained in permanent storage, such as a computer readable medium. In a client/server environment, such software programming code may be stored on a client or a server. The software programming code may be embodied on any of a variety of known media for use with a data processing system. This includes, but is not limited to, magnetic and optical storage devices such as disk drives, magnetic tape, compact discs (CD's), digital video discs, (DVD's), and computer instruction signals embodied in a transmission medium with or without a carrier wave upon which the signals are modulated. For example, the transmission medium may include a communications network, such as the Internet. Introductory Comments. A virtual node is the combination of a dedicated memory segment, a dedicated device group (which can contain no devices), and at least one CPU. A virtual machine implementer, such as a virtual machine monitor or machine emulator or simulator, disguises the virtual machine, so that an operating system that issues calls to the virtual machine can use only the virtual node resources. A virtual CPU is an object that appears to be a CPU from the perspective of a virtual machine. The operating system is unaware that it is controlling a virtual CPU rather than a physical CPU. The virtual machine implementer can replace the CPU context with several virtual CPU contexts, hence virtualizing more than one CPU based on one physical CPU. Embodiment 1. Turning now to the drawings, reference is initially made to FIG. 1, which is a block diagram of a cluster-based virtual computing system 10 that is constructed and operative in accordance with a disclosed embodiment of the invention. A plurality of user applications 12, 14, 16 execute simultaneously, supported by a guest operating system 18, which can be any conventional unmodified operating system supported by the instruction set architecture (ISA) of a plurality of nodes 22, 24, 26, e.g., Microsoft Windows®, Unix®, Linux®, or Solaris® X86 in the case of the X86/IA32 ISA. The guest operating system 18 controls a virtual machine 20, which presents itself to the guest operating system 18 as though it were a conventional real machine. While the system 10 is disclosed with reference to the X86/IA32 family of processors, the invention is not limited to the X86/IA32 family of processors, but is applicable to other computer architectures. While three nodes are shown, the system 10 is scalable, and any number of nodes may be present, depending on the needs of a particular application and the performance desired. The nodes 22, 24, 26 each comprise computer hardware 28, which in a current embodiment use the X86/IA32 ISA. Instructions of the guest operating system 18 are distributed for execution among the nodes 22, 24, 26 as though the system 10 were a single SMP machine with NUMA-like shared memory. This “virtual SMP” operation is transparent to the guest operating system 18 and to the applications 12, 14, 16, which consequently benefit from enhanced computing speed without having to be “cluster-aware.” The hardware 28 includes nodal memory 30 and may also be provided with many other types of conventional personal computer devices 32, for example, I/O devices and NIC's or other network communications facilities. Different versions of the X86/IA32 ISA compatible processor may be placed in different nodes, and various other aspects of the computer hardware may vary in different nodes. For example, the processor speed, bus speed, memory configuration, and I/O facilities may vary among the different nodes. It is only necessary that the different nodes all support a common ISA. Even this limitation can removed by using a full machine emulator to emulate an ISA that differs from the ISA of the system on which it is running. The system 10 is not dependent on any particular virtual machine implementation technique in any particular node. This point is emphasized in the exemplary configuration shown in FIG. 1, in which the nodes 22, 24 are provided with virtual machine monitors 34, 36, which can differ in implementation technique or hardware. For example, the virtual machine monitors 34, 36 could be different products, such as the above noted plex86, Xen (available via the Internet at the URL www.cl.cam.ac.uk/Research/SRG/netos/xen/downloads.html), VMWare workstation, Microsoft virtual server, or any other similar product. The node 26 does not have a virtual machine monitor. Instead, it is virtualized by an emulator 38, which can be the Bochs IA-32 Emulator. One of the main functions of a virtual computer is virtualized execution of the kernel code. Virtualized execution means that the guest operating system 18 receives effectively the same results from having its code executed on a virtual computer as on a real computer. Code of the guest operating system 18 is ultimately executed via the virtual machine 20 on the CPU's of the hardware 28. Therefore, a core element in the functionality of a virtual computer is the virtualization of the CPU instructions, the execution of which would otherwise break the virtualization and cause inconsistent operation or even total breakdown of the guest operating system. To this end, virtualized kernel code execution is performed in the virtual machine monitors 34, 36, and emulated in the emulator 38. The virtual machine monitors 34, 36 catch faults, exceptions and interrupts generated in the hardware 28, whether arising in the CPU or in other components of the hardware 28. The main task of the virtual machine monitors 34, 36 is to handle the faults, exceptions and interrupts in a manner that leads the guest operating system 18 to perceive that its own execution is as expected. Thus, the virtual machine can be implemented using any combination of the above-noted known techniques, e.g., virtual machine monitor, emulation with or without binary translation, or combinations thereof, or variants of a hosted architecture. The system 10 can be constructed using different types of emulators and different types of virtual machine monitors in many combinations. Memory coherence among the nodes 22, 24, 26 is achieved by a memory management module 40, which maintains copies of all memory content on each instance of the memory 30, and maintains a record of page or sub-page validations and invalidations. Similarly, a single coherent I/O view is achieved by an I/O management module 42. The details of the memory management module 40 and the I/O management module 42 are disclosed in further detail hereinbelow. A private network 44 provides rapid internodal communication, which is necessary for diverse functions of the virtual machine monitors 34, 36 and the emulator 38, including operation of the memory management module 40, the I/O management module 42, and processing of hardware and software interrupts between the nodes 22, 24, 26. The private network 44 may be realized using standard networking equipment. High bandwidth, low-latency network elements are used to boost performance. Standard host operating system NIC drivers, for example Linux NIC drivers, can be used to operate NIC's for the private network 44 as one of the devices 32 in each of the nodes 22, 24, 26. Other NIC's may also be included among the devices 32 for guest operating system outbound network communications beyond the cluster of the system 10. Virtual Machine Monitor. As shown in FIG. 1, the virtual machine monitor 34 runs on bare hardware. It is capable of supporting one or more virtual machines, but has the disadvantage that I/O devices must be supported by this type of virtual machine monitor. Reference is now made to FIG. 2, which is a detailed block diagram of an alternate virtual machine monitor 46 that is constructed and operative in accordance with a disclosed embodiment of the invention, and which is suitable for use as the virtual machine monitor 34 in the system 10 (FIG. 1), and in the other embodiments of a virtual computing system disclosed herein. The virtual machine monitor 46 either integrally includes, or can access a VM driver 48 that loads the virtual machine monitor 46 into kernel memory, so that it can run at a privileged level. The virtual machine monitor 46 employs the services of an unmodified full host operating system 47 to control the hardware 5. This method of operation is similar to the approach of the above-noted U.S. Pat. No. 6,496,847, in which a user-level emulator accepts commands from a virtual machine monitor via a specialized system-level driver and processes these commands as remote procedure calls. The emulator is able to issue host operating system calls and thereby access the physical system devices via the host operating system. The host operating system itself thus handles execution of certain virtual machine instructions, such as accessing physical devices. However, the technique of U.S. Pat. No. 6,496,847 is only disclosed with respect to a single hardware node. The system 10 (FIG. 1) also differs from the disclosure of the above-noted U.S. Pat. No. 6,075,938, in which the virtual machine monitor is only shown to run on bare hardware, and to control a single multiprocessing computer. Furthermore, the system disclosed in U.S. Pat. No. 6,075,938 requires kernel modifications of the host operating system to operate successfully. An implementation of the virtual machine monitor 46 is found in the computer program listing appendix. Reference is now made to FIG. 3, which is a detailed block diagram of an alternate virtual machine monitor 54 that is constructed and operative in accordance with a disclosed embodiment of the invention. The virtual machine monitor 54 can be used in any of the embodiments of a virtual computing system disclosed herein. The virtual machine monitor 54 does not rely upon the host operating system, but instead includes a management system 56, which is mainly used during boot-up and for coordinating private network communications during normal operation. The management system 56 maintains a virtual PCI controller 58, which serves as a proxy between the guest operating system and the physical PCI controllers. During boot-up, the virtual PCI controller 58 collects hardware information from the underlying hardware 5. Exploiting flexibilities of the PCI specification, it rearranges the PCI devices in the local node and throughout the cluster, using virtual PCI-to-PCI bridges. The virtual PCI controller 58 also ascertains that there are no conflicts in the I/O ports and memory regions used by the physical PCI devices on the individual hardware 5 or elsewhere in the cluster. Thus, the virtual PCI controller 58 makes the separate PCI buses of the individual nodes 22, 24, 26 (FIG. 1) appear to the guest operation system 18 as a single PCI address space, i.e., a single bridged virtual PCI bus. Currently prevalent commodity operating systems do not support multiple PCI buses. Nevertheless, in some embodiments, the virtual PCI controller 58 may have the capability of implementing multiple virtual PCI buses in anticipation that they may be supported by future commodity operating systems. Subsequently, the virtual PCI controller 58 serves as a sniffer for PCI configuration actions taken by the guest operating system, and tracks any changes made by the guest operating system to the PCI devices' I/O ports and memory regions. It respects such changes and forwards them to the PCI host of the appropriate physical node. It is also responsible for updating internal tables regarding I/O port and memory region assignments within the cluster. The virtual PCI controller 58 emulates hot-pluggable PCI events for the guest operating system. This allows for dynamic node addition and removal. If and when the physical hardware generates hot-pluggable PCI events, it is the responsibility of the virtual machine monitor 54 to forward these events to the guest operating system. The management system 56 includes a virtual DMA controller 60, which is a virtual layer that is capable of forwarding remote DMA requests between the guest operating system and remote nodes. The virtual DMA controller 60 is implemented by catching (intercepting) exceptions relating to reserved I/O ports assigned to a corresponding physical DMA Controller, which may be a third party device. It is possible to differentiate DMA operations that can be performed entirely locally from those in which either or both the device or the memory area are remote. DMA operations, which are entirely local, are forwarded as quickly as possible to a physical DMA controller of the local hardware 5, and are performed with almost no delay. DMA operations that involve memory and a device that does not reside on the same node are handled by transferring remote pages to the node where the device resides via the private network 44, and executing the DMA operation on that node. In a normal PCI environment, multiple DMA controllers exist concurrently; possibly different DMA controllers may exist on different add-on cards, i.e., “first party” DMA controllers. Therefore, there needs to be a general solution to deal with the multitude of controllers. Each card may have its own rules and semantics for communicating with its respective DMA controller. However, there are a few commonly-used methods, each having its own semantics. The virtual DMA controller 60 (FIG. 3) may provide a high-level language for defining in a unified manner, which I/O Ports, memory addresses, and sequences are required to be intercepted by the virtual machine monitor 54. Such values are monitored and recorded by the virtual machine monitor 54 during normal operation. When a DMA operation involving a first party DMA controller is initiated, usually by writing a certain value to a DMA controller port or memory register, the DMA operation is performed and the memory is marked by the virtual DMA controller 60 as invalid or locked on all other machines except the machine on which the DMA controller resides. Once notification of a successful DMA operation from a card is detected in a virtual machine monitor, either by an interrupt or by polling the appropriate I/O ports or memory ranges, that memory is again marked as unlocked, and available for access by remote machines. An alternate optimization method may be offered to allow incoming DMA operations, i.e., device to memory, to instantiate the operation in predefined reserve memory and copy the reserve memory to the guest operating system memory area once the operation is completed. This will prevent locking the memory accessed by the DMA operation for a long time. Bootup. When power is initially applied to a PCI device, the hardware remains inactive. In other words, the device only responds to configuration transactions. At power-on, the device has no memory and no I/O ports mapped in the computer's address space; every other device-specific feature, such as interrupt reporting, is disabled as well. Fortunately, every PCI motherboard is equipped with PCI-aware firmware: the BIOS. The firmware offers access to the device configuration address space by reading and writing registers in the PCI controller. At system boot, the firmware or the OS, for example the Linux kernel, performs configuration transactions with every PCI peripheral in order to allocate a safe place for any address region it offers. By the time a device driver accesses the device, its memory and I/O regions have already been mapped into the processor's address space. While a device driver can change this default assignment, in practice this is not done. The virtual PCI controller 58 takes control at this stage, reading all of the device configuration data, storing it in one node, e.g., a master node, and performs a remapping of all regions and resources. After this remapping is completed, it is delegated to the actual physical PCI controllers. The virtual PCI controller 58 scans the device list, and deals specially with certain device ID's that are known to have onboard DMA controllers, e.g., IDE cards, NIC's, and SCSI Controllers. Such DMA controllers are virtualized by the virtual DMA controller 60 so that DMA operations on these cards can take place. Eventually, the management system 56 requests configuration data for all devices, which is supplied by the virtual PCI controller 58. During normal operation the virtual PCI controller 58 continually tracks hardware configuration changes, including requests by the guest operating system to map or remap hardware regions. A table, mapping regions to actual node ID's, is maintained and updated. Memory Coherence. Each virtual machine presents a single coherent shared memory to the guest operating system, while physical memory 30 may be distributed across multiple nodes. To support this functionality transparently to the guest operating system, several techniques are used in different combinations, as may required to optimize the performance and reliability of a particular cluster-based system. Referring again to FIG. 1 and FIG. 3, in one embodiment memory mirroring is used across all the nodes 22, 24, 26 (FIG. 1). Memory mirroring provides protection for memory analogous to the protection afforded hard disk drives by RAID-1 disk mirroring. Reliability may be enhanced by using Chipkill™ memory, available from IBM, New Orchard Road, Armonk, N.Y., which allows multiple errors to be corrected. Another technique that can be employed to enhance reliability is elliptical curve cryptography (ECC) of data. Page or sub-page validations and write-invalidations are performed by the virtual machine monitor 34, and communicated to the other nodes using the private network 44. When an invalid page is required by a particular node, memory migration is performed, originating from a node having a valid copy of that page. As CPU's provide page-based memory access protection, implementation of page level granularity is sufficient in most cases. That is to say, page-size internodal memory transfers are performed. In some cases, where only a portion of a page is frequently invalidated, sub-page granularity can be achieved adaptively using the same page level granularity mechanism with additional software. This prevents false sharing and has the additional benefit of reducing internodal traffic on the private network 44. Further aspects of the coherent memory system used in embodiments of the present invention are described below in the subsection entitled “Memory Management Subsystem.” Embodiment 2. Reference is now made to FIG. 4, which is a block diagram of a cluster-based virtual computing system 64 that is constructed and operative in accordance with an alternate embodiment of the invention. In this embodiment there are a plurality of nodes 66, 68, 70 that are realized as multiprocessor computer hardware, including memory 72, I/O devices 85 and at least two CPUs 74, 76 per node. In one configuration of the system 64, each CPU in a node is included in a different virtual node, and is controlled by a different virtual machine. One virtual machine implementer is thus capable of using one physical CPU to virtualize a plurality of virtual CPU's. The system 64 employs two guest operating systems 18, 19 to concurrently execute multiple applications 12 13, 14, 15, 16, 17. Applications 12, 13, 14 are supported by the guest operating system 18. Applications 15, 16, 17 are supported by the guest operating system 19. The guest operating systems 18, 19 control virtual machines 86, 88, respectively. Each virtual machine has a plurality of virtual CPU's 21. Three virtual CPU's are shown; however, larger numbers of CPU's can be virtualized. Furthermore, none of the nodes 66, 68, 70, the virtual nodes 90, 92 or the virtual machines 86, 88 needs to be configured identically. In fact, the virtual machines 86, 88 can have different numbers of virtual CPU's. The virtual machines 86, 88 are provided with virtual memory 23, and virtual I/O devices 25. Two virtual machine implementers 78, 80 are included with each of the nodes 66, 68, 70 to implement the virtual machines 86, 88. The virtual machine implementers 78, 80 can be virtual machine monitors or emulators in any combination. The number of virtual machine implementers is only partially related to the number of CPU's in a node. The number of virtual machine implementers more closely relates to the implementation method itself. For example, multiple emulators can run over one CPU. Alternatively, each emulator can provide multiple virtual CPU's, as is disclosed below (Embodiment 3). A unit comprising the CPU 76, and a dedicated segment of the memory 72 makes use of only part of the computing resource of the hardware, such a device group, and is known as a virtual node. A virtual node may make use of one CPU of a multiprocessor, or more. The node 68, for example, has two virtual nodes 90, 92, which are enclosed by broken lines. The system 64 is flexible in its ability to deal with I/O devices that are physically distributed among the nodes 66, 68, 70 transparently to the guest operating systems 18, 19. To support this functionality, in the node 68 the virtual machine implementer 78 is associated with the virtual node 90, and the virtual machine implementer 80 with the virtual node 92. The I/O devices 85 in the node 68 may be arbitrarily segmented into device groups 82, 84, which are accessible to the virtual machines 86, 88, (in addition to the I/O devices in the nodes 66, 70). The I/O devices 85 in the node 68 are also accessible by the nodes 66, 70, using the private network 44. The device groups 82, 84 are controlled respectively by the virtual machine implementers 78, 80. In the node 68, the CPU 74 is controlled by the virtual machine implementer 78, the virtual machine 86, and the guest operating system 18. The CPU 76 is controlled by the virtual machine implementer 80, the virtual machine 88, and the guest operating system 19. Thus, two operating systems simultaneously control one physical node. Embodiment 3 Reference is now made to FIG. 5, which is a block diagram of a cluster-based virtual computing system 94 that is constructed and operative in accordance with an alternate embodiment of the invention. The system 94 is similar to the system 64 (FIG. 4), but has even finer granularity. As in the system 64, the system 94 is provided with nodes in which there is more than one virtual machine implementer per physical node. In addition, one physical CPU is used to virtualize a plurality of virtual CPU's, which are distributed in the same or different virtual nodes. The system 94 has a node 69, which has a hardware configuration that is identical to the node 68 (FIG. 4). However, a virtual machine implementer 107 in the node 69 virtualizes the CPU 74 and participates in a virtual machine 95. A virtual machine implementer 109 virtualizes the CPU 76, and participates in two virtual machines 95, 97. It will be noted that the virtual machine 95 contains four virtual CPU's 21, while the virtual machine 97 has three virtual CPU's 21. A virtual node 103 includes the CPU 74 and shares the CPU 76 with another virtual node 105. Thus, in the system 94, the CPU 76 participates in two virtual nodes 103, 105, and is simultaneously controlled by the two guest operating systems 18, 19. It is the role of the virtual machine implementer to allow such coparticipation in an efficient way. It is possible to configure the nodes of the system 94 in many combinations. For example, all of the nodes may be configured with a plurality of virtual CPUs per physical CPU, which may belong to same or different virtual nodes. Furthermore, it is possible to increase the number of virtual CPUs virtualized by one single processor beyond those shown in the two virtual machines 95, 97, subject to practical limitations of overhead. Furthermore, the number of virtual nodes sharing one physical node can be increased, again subject to limitations of overhead. Embodiment 4. Reference is now made to FIG. 6 which is a block diagram of a cluster-based virtual computing system 120 in accordance with a disclosed embodiment of the invention. A plurality of user applications 12, 14, 16 execute simultaneously, supported by the guest operating system 18, which can be any conventional operating system, e.g., Microsoft Windows®, Linux®, Solaris® X86. The guest operating system 18 controls the virtual machine 20, which presents itself to the guest operating system 18 as though it were a conventional real machine. The system 120 has a plurality of nodes 122, 124, 126, 128. While four nodes are shown, the system 120 is scalable, and any number of nodes may be present, depending on the needs of a particular application and the performance desired. The nodes 122, 124, 126, 128 each comprise computer hardware 28, which in a current embodiment has the X86/IA32 architecture. However, as noted above, the invention is not limited to the X86/IA32 family of processors, but is applicable to other computer architectures. The hardware 28 includes nodal memory 30, and may also be provided with a NIC 130 or other network communications facilities, and with many other types of conventional personal computer I/O devices 132. The nodes 122, 124, 126, 128 may be identically configured. Alternatively, different versions of the X86/IA32 processor may be placed in different nodes. Other aspects of the computer hardware in different nodes may also vary in different nodes, e.g., processor speed, bus speed, memory configuration, and I/O facilities. In the nodes 122, 126, 128, each of the CPU's is provided with a virtual machine monitor 134. The node 124 is provided with two virtual machine monitors 136, 138, which share the resources of the hardware 28, as shown in the foregoing embodiments. In this embodiment, the virtual machine monitors 134, 136, 138 are driven entirely by interrupts, and do not schedule for themselves any processing slots. They only react to actions taken by the guest operating system 18 or by the applications 12, 14, 16, and to interrupts generated in the hardware 28. The virtual machine monitors 134, 136, 138 have a flexible policy for handling faults, exceptions and interrupts depending on their individual characteristics. This may be effected by a mechanism known as “scan before execute”, which, as implied by its name, scans the code prior to execution and causes software interrupts to occur at the relevant places. Alternatively, the policy may be effected by a mechanism known as dynamic translation. Both of these techniques scan the code, differentiating between code that can be run natively, i.e., directly on the hardware 28, and the code that should not be run natively. For the latter, the code is altered either to generate a trap to the virtual machine monitor or to jump directly to a virtual machine monitor function. The virtual machine monitor can then emulate a current instruction that should not be run natively. These techniques yield reasonable efficiency, as in practice most code can be run natively and only a small portion need to be emulated. Scanning the code prior to execution is not expensive, as the same code is often run many times, in which case only one scan is needed. In some cases, the X86/IA32 architecture permits passing faults, exceptions and interrupts to the guest operating system 18 without modification. In other cases, faults, exceptions and interrupts may be hidden from the guest operating system 18. In still other cases, faults, exceptions and interrupts are processed internally by the virtual machine monitors 134, 136, 138, which may direct subsequent actions to be taken with respect to the guest operating system 18. For instance, a new interrupt may be generated and sent to the guest operating system 18 for processing. Generating an interrupt is done by emulating the CPU behavior while getting an interrupt. For those instructions that require emulation or other modification, an integrated machine emulator, which is part of the virtual machine monitor is used. Memory Management Subsystem. Continuing to refer to FIG. 6, memory coherence among the memory 30 of the nodes 122, 124, 126, 128 is achieved by a memory management subsystem 140, which is integrated in the virtual machine implementers 134, 136, 138. The virtual machine implementers 134, 136, 138 are each provided with a memory access hook and I/O access for the memory management subsystem 140. The private network 44 provides rapid internodal communication that is necessary for the operation of the memory management subsystem 140. The virtual machine implementers 134, 136, 138 typically use a paging mechanism when the implementer is implemented as a virtual machine monitor to synchronize the memory 30. Memory caches are established on different nodes 122, 124, 126, 128 in order to allow faster access to recently used segments of the memory 30. The virtual machine implementers 134, 136, 138 initialize the memory management subsystem 140 using the call INIT( ). During initialization, the memory management subsystem 140 invalidates all local pages of the memory 30 for read and write access. During subsequent operation, the virtual machine implementers 134, 136, 138 calls the memory management subsystem 140 in order to obtain read or write access to a physical page, which is currently marked as invalid for the specified access type. The memory management subsystem 140 also calls the virtual machine implementers 134, 136, 138 when required in order to invalidate a page for a specified access type, provided that the page should no longer be accessed by the CPU in the hardware 28 for that particular type of access. Alternatively, the page is validated for a specified access type if it has become available for that type of access. The memory management subsystem 140 requests page invalidation or validation using a physical address. Virtual machine monitors, which are used as the virtual machine implementers 134, 136, 138 use a reverse page lookup mechanism in order to update the processor paging table and invalidate the processor translation lookaside buffer (TLB). A description of the interface used for page access control and retrieval by the memory management subsystem 140 is found in Table 2. TABLE 2 INV_PAGE (PHY_ADD, Invalidate request for a physical RW) page using its physical address and access type VLD_PAGE (PHY_ADD, Validate request for a physical page RW) using its physical address and access type GET_PAGE (PHY_ADD, Get read or write access to physical RW, BUFFER, LENGTH, memory address using its physical address OP) and access type. In the function GET_PAGE, the parameter RW is a flag indicating the type of access intended. The parameters BUFFER and LENGTH are used to pass data in the case of a write operation and return data for a read operation. In case of read-modify-write operation, the function is called with the parameter RW set to a value of RMW. The parameter OP is processor dependent, and would thus be different in a processor outside the X86/IA32 family. It can indicate any of several operations, for example, increment, decrement, store and return previous value, and test and set. For embodiments in which one or more emulators are used as the virtual machine implementers 134, 136, 138, the above techniques can also be used. The virtual machine implementers 134, 136, 138 in such embodiments call the memory management subsystem 140 each time physical memory access is needed. An API MEM_ACCESS(PHY_ADD, RW) provides memory access for a physical page using its physical address and access type as a replacement for the CPU paging mechanism used in the virtual machine monitor. It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and sub-combinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description. Appendix 1 The computer software on the compact disks containing the computer program listing appendix hereof may be installed and executed as follows: Hardware. Provide an IBM compatible personal computer with a minimum of 512 MB RAM and an Intel Pentium IV central processing unit, two IDE hard disks with a minimum of 40 Gigabytes of disk space. Each IDE hard disk should be connected to its own individual IDE controller. Software (Installation). Host Operating System (Located on the First IDE Controlled Hard Disk). Copy the file.CONFIG in the root folder stored in the appended CD-ROM into a temporary directory. Install the Linux 2.4.20 kernel available from Redhat, Corporate HQ: 1801 Varsity Drive, Raleigh, N.C. 27606, USA. Install and Compile the Linux 2.4.21 kernel patch available from Kernel Dot Org Organization, 3990 Freedom Circle, Santa Clara, Calif. 95054, USA using the .CONFIG file mentioned above. Add the mem=200M argument to the Linux boot command and reboot the Computer. Copy the files BIOS.HEX, SCMPVMMO.HEX, SCMPVMMS.HEX and USERMODE.HEX in the root folder stored in the appended CD-ROM into a temporary directory. Unhex the computer listing BIOS.HEX, SCMPVMMO.HEX, SCMPVMMS.HEX and USERMODE.HEX using HEX IT V1.8 or greater by John Augustine, 3129 Earl St., Laureldale, Pa 19605, USA creating the files BIOS, SCMPVMM.O, SCMPVMM.SH and USERMODE, respectively. Guest Operating System (Located on the Second IDE Controlled Hard Disk). Install the Linux 2.4.20 kernel available from Redhat, Corporate HQ: 1801 Varsity Drive, Raleigh, N.C. 27606, USA. Install and Compile the Linux 2.4.21 kernel patch available from Kernel Dot Org Organization, 3990 Freedom Circle, Santa Clara, Calif. 95054, USA using the above-noted .CONFIG file. Reboot the Computer. Running Instructions. The system should be run by a user with supervisor privileges on the Linux system (typically root). The system must be run from a text mode screen (not from within a X-windows terminal) on the host. Run the scmpvmm.sh shell script with a single parameter of start. Typically ‘sh scmpvmm.sh start’ Run the usermode program, Typically ‘./usermode’. | <SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention This invention relates to virtual computers. More particularly, this invention relates to improvements in a cluster-based symmetric multiprocessor. 2. Description of the Related Art The meanings of certain acronyms and terminology used herein are given in Table 1. TABLE 1 API Application programming interface CPU Central processing unit DMA Direct Memory Access - used by hardware devices, which are required to copy data to and from main system memory. DMA is used to relieve the CPU from waiting during memory accesses. False sharing In shared memory multiprocessors, when processors make references to different data items within the same block even though there is no actual dependence between the references. FSB Front-side bus NIC Network interface card NUMA Non-uniform memory access PCI Peripheral Component Interconnect - a standard for peripheral software and hardware interfaces. SMP Symmetric multiprocessor TLB Translation lookaside buffer VM Virtual machine VMM Virtual machine monitor A portion of the disclosure of this patent document, which includes a CD-ROM appendix, contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. The use of virtual computers (generally referred to as “virtual machines”) to enhance computing power has been known for several decades. For example, a classic system, VM, produced by IBM, enabled multiple users to concurrently use a single computer by running multiple copies of the operating system. Virtual computers have been realized on many different types of computer hardware platforms, including both single-processor and multi-processor units. Some virtual machine monitors are able to provide concurrent support for diverse operating systems. This requires the virtual machine monitor to present a virtual machine, that is a coherent view of the hardware, to each operating system. The above-noted VM system has evolved to the point where it is asserted that in one version, z/VM®, available from IBM, New Orchard Road, Armonk, N.Y., multiple operating systems can execute on a single server. Despite these achievements in virtual computing, practical issues remain. The currently dominant personal computer architecture, X86/IA32, which is used in the Intel Pentium™ and other Intel microprocessors, is not conducive to virtualization techniques for two reasons: (1) the instruction set of the CPU is not natively virtualizable; and (2) the X86/IA32 architecture has an open I/O architecture, which complicates the sharing of devices among different operating systems. This has been an impediment to continued advancements in the field. In general, it is inefficient, and probably impractical, for multiple operating systems to concurrently share common X86/IA32 hardware directly. System features of the X86/IA32 CPU are designed to be configured and used in a coordinated effort by only one operating system, e.g., paging and protection mechanisms, and segmentation. Limitations of the X86/IA32 architecture can be appreciated by a brief explanation of one known approach to virtual computers, in which a virtual machine monitor is used to provide a uniform execution environment within a computer. A virtual machine monitor is a software layer that in this approach is interposed between hardware of a single computer and one or more guest operating systems that support different applications. In this arrangement the virtual machine monitor interacts directly with the hardware, and exposes an expected interface to the guest operating systems. This interface includes normal hardware facilities, e.g., CPU, I/O, and memory. When virtualization is properly done, the guest operating systems are unaware that they are interacting with a virtual machine instead of directly with the hardware. For example, low level disk operations invoked by the operating systems, interaction with system timers, interrupts and exception handling are all managed transparently by the guest operating systems via the virtual machine monitor. To accomplish this, it is necessary that the virtual machine monitor be able to trap and execute certain hardware instructions dealing with the state of the processor. Significantly, the X86/IA32 employs four modes of protected operation, which are conveniently conceptualized as rings of protection, known as protection rings 0-3. Protection ring 0 is the most protected, and was designed for execution of the operating system kernel. Privileged instructions available only under protection ring 0 include instructions dealing with interrupt handling, and the modification of processor flags and page tables. Typical examples are store instructions for the global descriptor table (SGDT) and interrupt descriptor table (SIDT). Protection rings 1 and 2 were designed for other operating system services, e.g., device drivers. Protection ring 3, the least privileged, was intended for applications, and is also referred to as user mode. If it were possible to trap all of the privileged X86/IA32 instructions in user mode, it would be relatively straightforward for the virtual machine monitor to handle them using ordinary exception-handling techniques. Unfortunately, there are many privileged instructions of the X86/IA32 instruction set, which cannot be trapped under protection ring 3. Attempts to naively execute privileged instructions under protection ring 3 typically result in a general protection fault. Because of the importance of the X86/IA32 architecture, considerable effort has been devoted to overcoming its limitations with regard to virtualization. Virtual machines have been proposed to be implemented by software emulation of at least the privileged instructions of the X86/IA32 instruction set. Alternatively, binary translation techniques can be utilized in the emulator. Binary translation techniques in connection with a virtual machine monitor are disclosed in U.S. Pat. No. 6,397,242, the disclosure of which is incorporated herein by reference. Additionally or alternatively, combinations of direct execution and binary translation can be implemented. The open source Bochs IA-32 Emulator, downloadable via the Internet at the URL http://bochs.sourceforge.net/, is an example of a complete emulator. Another example is the SimOS environment, available via the Internet at the URL http://simos.stanford.edu/. The SimOS environment is adapted to the MIPS R4000 and R10000 and Digital Alpha processor families. Generally, the performance of emulators is relatively slow. Another known approach employs a hosted architecture. A virtual machine application uses a VM driver to load a virtual machine monitor at a privileged level. Typical of this approach are the disclosures of U.S. Pat. Nos. 6,075,938 and 6,496,847, which are incorporated herein by reference. The virtual machine monitor then uses the I/O services of a host operating system to accommodate user-level VM applications. Current examples of this approach include the VMware Workstation™, the VMware GSX Server™, both available from VMware, Inc., 3145 Porter Drive, Palo Alto, Calif. 94304, and the Connectix Virtual PC™, available from Microsoft Corporation, One Microsoft Way, Redmond, Wash. 98052-6399. Another example is the open source Plex86 Virtual Machine, available via the Internet at the URL http://plex86.sourceforge.net/. The hosted architecture is attractive due to its simplicity. However, it incurs a performance penalty because the virtual machine monitor must itself run as a scheduled application under the host operating system, and could even be swapped out. Furthermore, it requires emulators to be written and maintained for diverse I/O devices that are invoked by the virtual machine monitor. It is known in the art to use multiple processors in a single computer in order to enhance overall system performance. One known architecture is symmetric multiprocessing (SMP), in which application programs are processed by multiple processors that share a common operating system and memory. Typically, the processors share memory and the I/O bus or data path, and are controlled by a single instance of an operating system. In order to enhance performance, SMP systems may employ non-uniform memory access (NUMA), a method of configuring the microprocessors so that they can share memory locally. In a variation of multiprocessing systems, multiple relatively small computers, either uniprocessors or multiprocessors having relatively few processors, are linked together and coordinated to execute multiple applications, while serving one or more users. This arrangement is known as a cluster, or scaled-out arrangement. Some systems of this type can outperform corresponding SMP configurations. However, in the past it has been necessary that applications for cluster-based systems be specialized, so that they are cluster-aware. This has increased development expense, and in some cases, has impeded the use of standard commercial software on cluster-based systems. An unsuccessful attempt to implement a VM computing paradigm on cluster-based systems is disclosed in the document The Memory and Communication Subsystem of Virtual Machines for Cluster Computing , Shiliang Hu and Xidong Wang, January 2002 (Hu et al.), published on the Internet at the URL http://www.cs.wisc.edu/˜wxd/report/ece902.pdf. In this proposed arrangement, multiple SMP clusters of NUMA-like processors are monitored by virtual machine monitors. A cluster interconnect deals with message passing among the clusters. The system consists of multiple virtual machines that operate under a single operating system, and support parallel programming models. While a virtual computer built according to this paradigm would initially appear to be highly scalable, preliminary simulations of the communication and memory subsystems were discouraging. A further difficulty is posed by limitations of current operating systems, which are generally unaware of the locality of NUMA-type memory. According to Hu et al., the proposed paradigm could not be reduced to practice until substantial technological changes occur in the industry. Thus Hu et al. appears to have encountered a well-known difficulty: cluster machines generally, and NUMA machines in particular, can be scaled up successfully only if some way is found to ensure a high computation to communication ratio in regard to both data distribution and explicit communication among the clusters and processors. The most successful of the solutions noted above, in the case of the IBM z/VM product, have relied upon revisions and optimizations of the underlying computer hardware in order to overcome the issues encountered by Hu et al., and to increase performance generally, or have required kernel modifications of operating system software, in the case of the above-noted VMWare products. These approaches are costly in terms of product development, marketing, and maintenance, and often commercially impracticable, due to secrecy policies of operating system software vendors. | <SOH> SUMMARY OF THE INVENTION <EOH>According to a disclosed embodiment of the invention, an improved cluster-based collection of computers (nodes) is realized using unmodified conventional computer hardware and unmodified operating system software. Software is provided that enable a virtual machine to be presented to a guest operating system, wherein each node participating with the virtual machine has its own emulator or virtual machine monitor. VM memory coherency and I/O coherency are provided by hooks, which result in the manipulation of internal processor structures. A private network provides communication among the nodes. The invention provides a method for executing a software application in a plurality of computing nodes has node resources, wherein the nodes include a first node and a second node that intercommunicate over a network, and the nodes is operative to execute a virtual machine that runs under a guest operating system. The method is carried out by running at least a first virtual machine implementer and a second virtual machine implementer on the first node and the second node, respectively, and sharing the virtual machine between the first virtual machine implementer and the second virtual machine implementer. An aspect of the method includes running the software application over the guest operating system, so that commands invoked by the software application are monitored or emulated by the first virtual machine implementer and by the second virtual machine implementer on the first node and the second node, while the node resources of the first node and the second node are shared by communication over the network. According to an additional aspect of the method, at least one of the first virtual machine implementer and the second virtual machine implementer is a virtual machine monitor. According to one aspect of the method, at least one of the first virtual machine implementer and the second virtual machine implementer is an emulator. According to still another aspect of the method, at least the first node has a first virtual node that includes a first physical CPU of the first node and has a second virtual node that includes a second physical CPU of the first node. According to another aspect of the method, there are a plurality of virtual machines including a first virtual machine and a second virtual machine, wherein the first virtual machine and the second virtual machine have a plurality of virtual CPU's that are virtualized by the first virtual machine implementer in the first node based on a first physical CPU and by the second virtual machine implementer in the second node based on a second physical CPU, respectively. According to yet another aspect of the method, and a first virtual node includes the first physical CPU and the second physical CPU. According to a further aspect of the method, the first virtual machine implementer virtualizes at least one of the virtual CPU's of the first virtual machine based on the first physical CPU and virtualizes at least one of the virtual CPU's in the second virtual machine based on the second physical CPU. Another aspect of the method includes providing a management system for the first virtual machine implementer and the second virtual machine implementer to control the first node and the second node, respectively, wherein the management system includes a wrapper for receiving calls to a device driver from the first virtual machine implementer, the wrapper invoking the device driver according to a requirement of the first virtual machine implementer. A further aspect of the method includes providing a virtual PCI controller for the management system to control a physical PCI controller in one of the nodes. Yet another aspect of the method includes providing a virtual DMA controller for the management system to control a physical DMA controller in one of the nodes. Still another aspect of the method includes providing a virtual PCI controller to control a physical PCI controller in one of the nodes, and during a bootup phase of operation scanning a device list with the virtual PCI controller to remap memory regions and resources and identify devices having on-board DMA controllers. In one aspect of the method the virtual machine implementer maintains mirrors of a memory used by the guest operating system in each of the nodes, the method further including write-invalidating at least a portion of a page of the memory in one of the nodes, and transferring a valid copy of the portion of the page to the one node from another of the nodes via the network. The invention provides a computer software product, including a computer-readable medium in which computer program instructions are stored, which instructions, when read by a computer, cause the computer to perform a method for executing a software application in a plurality of computing nodes has node resources, wherein the nodes include a first node and a second node that intercommunicate over a network, and the nodes is operative to execute a virtual machine that runs under a guest operating system. The method is carried out by running at least a first virtual machine implementer and a second virtual machine implementer on the first node and the second node, respectively, and sharing the virtual machine between the first virtual machine implementer and the second virtual machine implementer. The invention provides a computer system for executing a software application, including a plurality of computing nodes, the plurality of computing nodes including at least a first node and a second node, a network connected to the first node and the second node providing intercommunication therebetween, a first virtual machine implementer and a second virtual machine implementer executing on the first node and the second node, respectively. The system further includes a virtual machine implemented concurrently by at least the first virtual machine implementer and the second virtual machine implementer, and a guest operating system executing over the virtual machine, wherein the software application executes over the guest operating system, so that commands invoked by the software application are received by the first virtual machine implementer and the second virtual machine implementer on the first node and the second node, while the node resources of the first node and the second node are shared by communication over the network. | 20040421 | 20150428 | 20050217 | 75569.0 | 2 | SILVER, DAVID | Cluster-based operating system-agnostic virtual computing system | SMALL | 0 | ACCEPTED | 2,004 |
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