Claims
- 1. A drive system for a modular conveyor belt, the drive system comprising:a plurality of belt drive surfaces spaced across the width of the underside of each row of a modular conveyor belt; a drive shaft rotatably supported with an axis extending in the width direction of the belt; a plurality of sprockets mounted at spaced apart locations along the drive shaft and including sprocket drive surfaces circumferentially spaced around the periphery of each sprocket and arranged in rows from sprocket to sprocket to drivingly engage corresponding belt drive surfaces of the belt rows; wherein the sprocket drive surfaces define a variable timing sequence with respect to the corresponding belt drive surfaces across the width of the conveyor belt when the belt and the drive shaft are unloaded.
- 2. A drive system as in claim 1 further comprising a drive motor coupled to the drive shaft at a side of the conveyor belt and wherein the sprocket drive surfaces are relatively advanced in timing across each row with distance along the shaft from the drive motor.
- 3. A drive system as in claim 1 further comprising a drive motor coupled to the drive shaft at a side of the conveyor belt and wherein the belt drive surfaces are relatively retarded in timing across each row of the conveyor belt with distance from the drive motor.
- 4. A drive system as in claim 1 wherein the drive shaft has a generally circular cross section with a raised key parallel to the axis and wherein the sprockets form generally circular bores each with a keyway to receive the circular drive shaft and the raised key and wherein the keyways vary in circumferential extent depending on their position on the drive shaft.
- 5. A drive system as in claim 1 wherein the sprockets include teeth having leading and trailing edges along the periphery of the sprockets, the leading edges forming the sprocket drive surfaces, and wherein the distance between the leading edge and the trailing edge of each tooth of a sprocket depends on the sprocket's position on the drive shaft.
- 6. A drive system as in claim 1 wherein each of the sprockets includes a central bore having a bore surface registered radially at an angle relative to a sprocket drive surface and wherein the angle of registration for each sprocket depends on the sprocket's position on the shaft.
- 7. A drive system as in claim 1 wherein the drive shaft has a generally circular cross section with a raised, tapered keyway.
- 8. A drive system for a modular conveyor belt, the drive system comprising:a plurality of belt drive surfaces spaced across the width of the underside of each row of a modular conveyor belt; a drive shaft rotatably supported with an axis extending in the width direction of the belt; a plurality of sprockets mounted at spaced apart locations along the drive shaft and including sprocket drive surfaces circumferentially spaced around the periphery of each sprocket and arranged in rows of sprocket drive surfaces from sprocket to sprocket to drivingly engage corresponding belt drive surfaces of the belt rows; wherein the sprocket drive surfaces of each row define a curve in non-parallel relation to the axis of the drive shaft in an unloaded condition.
- 9. A drive system as in claim 8 wherein the sprockets include teeth having leading and trailing edges along the periphery of the sprockets, the leading edges forming the sprocket drive surfaces, and wherein the distance between the leading edge and the trailing edge of each tooth of a sprocket depends upon the sprocket's position on the drive shaft.
- 10. A drive system as in claim 8 wherein each of the sprockets includes a central bore having a bore surface oriented at an angle relative to a sprocket drive surface and wherein the angle for each sprocket depends on the sprocket's position on the shaft.
- 11. A drive system for driving a modular conveyor belt with a twisted shaft, the drive system comprising:a plurality of belt drive surfaces spaced across the width of the underside of each row of a modular conveyor belt; a drive shaft rotatably supported with an axis extending in the width direction of the belt; a plurality of sprockets mounted at spaced apart locations along the drive shaft and including sprocket drive surfaces circumferentially spaced around the periphery of each sprocket and arranged in rows of sprocket drive surfaces from sprocket to sprocket to drivingly engage corresponding belt drive surfaces of the belt rows; and means, associated with at least some of the drive surfaces, for varying the timing relationship among the drive surfaces so that the sprocket drive surfaces engage the belt drive surfaces across the entire width of the belt when the shaft is twisted.
- 12. A drive system as in claim 11 wherein the means for varying the timing relationship comprises a tapered key formed on the drive shaft.
- 13. A drive system as in claim 11 wherein the means for varying the timing relationship comprises the angular registration of the sprocket drive surfaces to a bore surface forming a bore wall in a drive-shaft-accommodating bore formed in each sprocket.
- 14. A drive system as in claim 11 wherein the means for varying the timing relationship comprises sprocket bores formed centrally in the sprockets to accommodate the drive shaft and keyways defining a portion of the bores, wherein the keyways vary in circumferential extent depending on their position on the drive shaft.
- 15. A drive system as in claim 11 wherein the means for varying the timing relationship comprises sprocket teeth having leading and trailing edges formed on the periphery of the sprockets defining the sprocket drive surfaces and wherein the distance between the leading edge and the trailing edge of each tooth of a sprocket depends on the sprocket's position on the drive shaft.
- 16. A method of compensating for shaft twist in a modular conveyor system, comprising:mounting a set of sprockets having sprocket drive surfaces formed on peripheral sprocket teeth on a drive shaft to engage belt drive surfaces in a conveyor belt; adjusting the timing of the sprocket drive surfaces relative to the belt drive surfaces across the width of the belt.
- 17. A method of compensating for shaft twist in a modular conveyor system as in claim 16, wherein adjusting the timing comprises:forming the set of sprockets with the peripheral sprocket teeth varying in circumferential extent from sprocket to sprocket; arranging the sprockets on the drive shaft with the sprocket having the teeth extending least in circumferential extent mounted closest to a driven end of the drive shaft.
- 18. A method of compensating for shaft twist in a modular conveyor system as in claim 16, wherein adjusting the timing comprises:forming the set of sprockets with a central bore having a bore wall whose angular registration relative to the driving surfaces of the teeth varies from sprocket to sprocket; arranging the sprockets on the drive shaft with the angular registration varying with position along the drive shaft.
- 19. A method of compensating for shaft twist in a modular conveyor system as in claim 16, wherein adjusting the timing comprises:forming a key having a tapered edge on the drive shaft; forming keyways in the sprockets to accommodate the key.
- 20. A method of compensating for shaft twist in a modular conveyor system as in claim 16, wherein adjusting the timing comprises:forming the set of sprockets with keyways that vary in circumferential extent from sprocket to sprocket; forming a rectangular key on the drive shaft; arranging the sprockets on the drive shaft with the keyways varying in circumferential extent with position from an end of the drive shaft.
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the priority of U.S. Provisional Patent Application No. 60/333,233, filed on Nov. 14, 2001.
US Referenced Citations (11)
Provisional Applications (1)
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Number |
Date |
Country |
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60/333233 |
Nov 2001 |
US |