Belt tensioner

• US 4,596,538 A
• Filed: 08/23/1984
• Issued: 06/24/1986
• Est. Priority Date: 08/23/1984
• Status: Expired due to Term

• Current Assignee: Dayco Products LLC
• Original Assignee: Dayco Europe Srl (Park-Ohio Holdings Corporation)
• Inventors: Henderson, Dewey D.
• Primary Examiner(s): Levy, Stuart S.
• Assistant Examiner(s): MATECKI, KATHERINE A
• Application Number:
  US06/643,504
• Time in Patent Office: 670 Days
• Field of Search: 474/117, 474/133, 474/134, 474/135, 474/136, 474/138, 474/115
• US Class Current: 474/135
• CPC Class Codes: F02B 2275/06 Endless member is a belt
• CPC Class Codes: F16H 2007/081 Torsion springs
• CPC Class Codes: F16H 7/1218 of the dry friction type

Abstract

A tensioner for a power transmission belt that is adapted to be operated in an endless path is provided and comprises a support unit for being fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, a mechanical spring unit operatively associated with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt, and a frictional dampening unit operatively associated with the support unit and the belt engaging unit to dampen the movement of the belt engaging unit relative to the support unit in at least one direction of movement thereof. The dampening unit has a longitudinal axis and the support unit comprises a shaft having a longitudinal axis and being fixed from movement relative to the belt engaging unit. The belt engaging unit has a portion thereof rotatably carried by the shaft so as to rotate relative to the shaft. The dampening unit comprise a pair of frictionally engaging first and second parts with the first part comprising an annular pad of friction material that is coaxially disposed and axially movable on the shaft relative to the second part and another spring that urges the first part against the second part with a certain spring force.

Claims

1. In a tensioner for a power transmission belt that is adapted to be operated in an endless path, said tensioner comprising a support means for being fixed relative to said belt, a belt engaging means carried by said support means and being movable relative thereto, mechanical spring means operatively associated with said support means and said belt engaging means for urging said belt engaging means relative to said support means and against said belt with a force to tension said belt, and frictional dampening means operatively associated with said support means and said belt engaging means to dampen the movement of said belt engaging means relative to said support means in at least one direction of movement thereof, said dampening means having a longitudinal axis, said support means comprising a shaft means having a longitudinal axis and being fixed from movement relative to said belt engaging means, said belt engaging means having a portion thereof being rotatably carried by said shaft means so as to rotate relative to said shaft means, the improvement wherein said dampening means comprises a pair of frictionally engaging first and second parts with said first part comprising an annular pad of friction material that is coaxially disposed and axially movable on said shaft means relative to said second part, and another spring means urging said first part against said second part with a certain spring force.

2. A tensioner as set forth in claim 1 wherein said first part of said dampening means is operatively interconnected to said portion of said belt engaging means to rotate therewith.

3. A tensioner as set forth in claim 2 wherein said first part of said dampening means has spline means, said portion of said belt engaging means having spline means operatively interconnected to said spline means of said first part whereby said first part is adapted to rotate with said portion of said belt engaging means while being axially movable relative thereto.

4. A tensioner as set forth in claim 3 wherein said spring means of said dampening means is disposed intermediate said portion of said belt engaging means and said first part of said dampening means.

5. A tensioner as set forth in claim 1 wherein said first part of said dampening means is operatively interconnected to said support means and said second part of said dampening means comprises said portion of said belt engaging means.

6. A tensioner as set forth in claim 5 wherein said first part of said dampening means has spline means, said support means having spline means operatively interconnected to said spline means of said first part whereby said first part does not rotate with said portion of said belt engaging means while being axially movable relative thereto.

7. A tensioner as set forth in claim 6 wherein said spring means of said dampening means is disposed intermediate said support means and said first part of said dampening means.

8. A tensioner as set forth in claim 1 wherein said spring means of said dampening means is annular and is coaxially disposed on said shaft means.

9. A tensioner as set forth in claim 1 wherein said shaft means comprises a tubular member.

10. In a tensioner for a power transmission belt that is adapted to be operated in an endless path, said tensioner comprising a support means for being fixed relative to said belt, a belt engaging means carried by said support means and being movable relative thereto, mechanical spring means operatively associated with said support means and said belt engaging means for urging said belt engaging means relative to said support means and against said belt with a force to tension said belt, and dampening means operatively associated with said support means and said belt engaging means to dampen the movement of said belt engaging means relative to said support means in at least one direction of movement thereof, said dampening means having a longitudinal axis, said spring means having a longitudinal axis and being spiraled about said axis thereof, said support means comprising a shaft means having a longitudinal axis and being fixed from movement relative to said belt engaging means, said shaft means carrying said dampening means and said spring means in spaced apart side-by-side relation thereon with said axis of said shaft means being substantially coaxial with said axes of said dampening means and said spring means whereby said dampening means and said spring means are coaxially spaced apart and are coaxially aligned by said shaft means, said belt engaging means having a portion thereof disposed between said dampening means and said spring means and being rotatably carried by said shaft means so as to rotate relative to said shaft means whereby said dampening means and said spring means are coaxially spaced apart from each other by said portion of said belt engaging means, the improvement wherein said dampening means comprises a pair of frictionally engaging first and second parts with said first part comprising an annular pad of friction material that is axially movable on said shaft means relative to the second part, and another spring means urging said first part against said second part with a certain spring force.

11. A tensioner as set forth in claim 10 wherein said first part of said dampening means is operatively interconnected to said portion of said belt engaging means to rotate therewith.

12. A tensioner as set forth in claim 11 wherein said first part of said dampening means has spline means, said portion of said belt engaging means having spline means operatively interconnected to said spline means of said first part whereby said first part is adapted to rotate with said portion of said belt engaging means while being axially movable relative thereto.

13. A tensioner as set forth in claim 12 wherein said spring means of said dampening means is disposed intermediate said portion of said belt engaging means and said first part of said dampening means.

14. A tensioner as set forth in claim 10 wherein said first part of said dampening means is operatively interconnected to said support means and said second part of said dampening means comprises said portion of said belt engaging means.

15. A tensioner as set forth in claim 14 wherein said first part of said dampening means has spline means, said support means having spline means operatively interconnected to said spline means of said first part whereby said first part does not rotate with said portion of said belt engaging means while being axially movable relative thereto.

16. A tensioner as set forth in claim 15 wherein said spring means of said dampening means is disposed intermediate said support means and said first part of said dampening means.

17. A tensioner as set forth in claim 10 wherein said spring means of said dampening means is annular and is coaxially disposed on said shaft means.

18. A tensioner as set forth in claim 10 wherein said shaft means comprises a tubular member.

19. In a tensioner for a power transmission belt that is adapted to be operated in an endless path, said tensioner comprising a support means for being fixed relative to said belt, a belt engaging means carried by said support means and being movable relative thereto, and mechanical spring means operatively associated with said support means and said belt engaging means for urging said belt engaging means relative to said support means and against said belt with a force to tension said belt, said spring means having a longitudinal axis and being spiraled about said axis thereof, said support means comprising a shaft means having a longitudinal axis and being fixed from movement relative to said belt engaging means, said belt engaging means having a portion thereof rotatably carried by said shaft means so as to rotate relative to said shaft means, said portion of said belt engaging means having a slot therein, said spring means having an inner coil provided with an inner end bent at an angle relative to said inner coil and being received in said slot to interconnect said spring means to said portion of said belt engaging means, the improvement comprising a protective member disposed between said portion of said belt engaging means and said inner coil of said spring means adjacent said inner end thereof to tend to protect said inner coil.

20. A tensioner as set forth in claim 19 wherein said protective member comprises polymeric material.

21. A tensioner as set forth in claim 19 wherein said portion of said belt engaging means comprises a substantially cylindrical tubular portion telescopically disposed on said shaft means, said protective member being arcuate to substantially conform to said cylindrical tubular portion and said inner coil.

22. A tensioner as set forth in claim 21 wherein said protective member is thicker adjacent said bent inner end of said spring means and has the thickness thereof decrease in a tapering manner as said protective member extends away from said bent inner end in a circumferential direction on said cylindrical tubular portion.

23. A tensioner as set forth in claim 22 wherein said protective member has a part thereof disposed in said slot of said tubular portion to prevent rotational movement of said protective member relative to said tubular portion.

24. A tensioner as set forth in claim 19 wherein said shaft means comprises a tubular member.

25. In a tensioner for a power transmission belt that is adapted to be operated in an endless path, said tensioner comprising a support means for being fixed relative to said belt, a belt engaging means carried by said support means and being movable relative thereto, mechanical spring means operatively associated with said support means and said belt engaging means for urging said belt engaging means relative to said support means and against said belt with a force to tension said belt, said spring means having a longitudinal axis and being spiraled about said axis thereof, said support means comprising a shaft means having a longitudinal axis and being fixed from movement relative to said belt engaging means, said belt engaging means having a portion thereof rotatably carried by said shaft means so as to rotate relative to said shaft means, said support means comprising a cup-shaped casing having an open end and receiving said spring means therein, and an antifriction disc-like member disposed on said shaft means between said portion of said belt engaging means and said spring means, the improvement wherein said disc-like member substantially seals closed said open end of said casing.

26. A tensioner as set forth in claim 25 wherein said open end of said casing has an internal peripheral surface, said disc-like member having an outer peripheral edge means at least partially sealing against said internal peripheral surface.

27. A tensioner as set forth in claim 25 wherein said shaft means comprises a tubular member.