Three-dimensional roller locking sprags

• US 5,482,144 A
• Filed: 07/27/1994
• Issued: 01/09/1996
• Est. Priority Date: 07/27/1994
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Administrator of National Aeronautics and Space Administration
• Inventors: Vranish, John M.
• Primary Examiner(s): Oberleitner, Robert J.
• Assistant Examiner(s): SCHWARTZ, CHRISTOPHER P
• Application Number:
  US08/280,979
• Time in Patent Office: 531 Days
• Field of Search: 188/6, 188/82.2, 188/82.3, 188/82.84, 188/82.8, 192/41 A, 192/45.1
• US Class Current: 188/82.8
• CPC Class Codes: F16D 2041/0603 Sprag details
• CPC Class Codes: F16D 41/064 the intermediate members wedging by rolling and having a circular cross-section, e.g. balls F16D41/061 takes precedence
• CPC Class Codes: F16D 41/07 between two cylindrical surfaces

Abstract

A torque coupling sprag system which provides contact between the sides of at least one groove and at least two contact surfaces angled with respect to the central axial direction of at least one rotatable 3-D sprag member located between a drive member and a reaction member. The surface contacts between the members include various combinations of surface segments arranged in a predetermined manner to define a desired configuration. The contact radius of the 3-D sprag member is significantly larger than its rolling radius; however, radii can be varied in size and shape independently of each other, particularly the contact radius.

Claims

1. A torque coupling sprag system, comprising:

a drive member selected from a male type and a female type member, said drive member including a first pair of mutually spaced apart and mutually inclined contact surfaces for directly contacting a sprag member, said sprag member having an outermost perimeter located in a plane normal to an axis of rotation of said sprag member,

a reaction member including a second pair of mutually spaced apart and mutually inclined contact surfaces for directly contacting said sprag member, and

said sprag member selected from a male type and a female type member opposite said selection of said drive member and said reaction member and located between and biased against said pairs of contact surfaces of both said drive member and said reaction member and having a third pair of mutually spaced apart contact surfaces in direct contact with said first pair of contact surfaces of said drive member and a fourth pair of mutually spaced apart contact surfaces in direct contact with said second pair of contact surfaces of said reaction member, at a location radially inside said outermost perimeter of said sprag member, and

wherein one pair of contact surfaces of said first and third pairs of contact surfaces and one pair of contact surfaces of said second and fourth pairs of contact surfaces, respectively, comprise curved contact surfaces having a predetermined radius of curvature, and

wherein said sprag member comprises a rotatable member having a radius of rotation and wherein said radius of curvature of said third and fourth pairs of contact surfaces is relatively large relative to said radius of rotation.

2. A sprag system in accordance with claim 1 wherein said sprag member comprises a member rotatable about said axis of rotation and said reaction member is inclined relative to said drive member and forming an angle therebetween defined by a straight line passing through said axis of rotation and said first and third pairs of contact surfaces and a straight line passing through said axis of rotation and said second and fourth pairs of contact surfaces.

3. A sprag system in accordance with claim 2 wherein said third and fourth pair of contact surfaces of said sprag member have a contact radius of curvature of a first value for contacting said first and second pair of contact surfaces of said drive member and said reaction member, respectively, and said sprag member has a radius of rotation about said axis of rotation of a second value where said third and fourth pairs of contact surfaces make contact with said first and second pairs of contact surfaces, wherein said contact radius of curvature being determined and shaped independently of said radius of rotation and said first value is greater than said second value.

4. A sprag system in accordance with claim 3 wherein R₂ >

>

R₁, where R₁ is the radius of rotation, and R₂ is the contact radius of curvature.

5. A sprag system in accordance with claim 4 wherein said first and second pairs of contact surfaces are located in grooves in an outer surface of said drive member and said reaction member, respectively, and wherein said third and fourth pairs of contact surfaces are respectively located on peripheral portions of said sprag member.

6. A sprag system in accordance with claim 5 wherein said grooves include pairs of flat surface segments in said drive member and said reaction member, said first and second pairs of contact surfaces respectively located on said flat surface segments, and wherein said peripheral portions of said sprag member include a pair of convex surface segments, said third and fourth pairs of contact surfaces respectively located on said convex surface segments.

7. A sprag system in accordance with claim 5 wherein said grooves include pairs of concave surface segments in said drive member and said reaction member, said first and second pairs of contact surfaces being respectively located on said concave surface segments, and wherein said peripheral portions of said sprag member include a pair of convex surface segments, said third and fourth pairs of contact surfaces being respectively located on said convex surface segments.

8. A sprag system in accordance with claim 5 wherein said grooves include pairs of convex surface segments in said drive member and said reaction member, said first and second pairs of contact surfaces respectively located on said convex surface segments, and wherein said peripheral portions of said sprag member include a pair of flat surface segments, said third and fourth pairs of contact surfaces respectively located on said flat surface segments.

9. A sprag system in accordance with claim 5 wherein said grooves include pairs of convex surface segments, in said drive member and said reaction member, said first and second pairs of contact surfaces respectively located on said convex surface segments, and wherein said tapered peripheral portions include a pair of concave surface segments, said third and fourth pairs of contact surfaces respectively located on said concave surface segments.

10. A sprag system in accordance with claim 4 wherein said first and second pairs of contact surfaces are located in peripheral outer surface portions of said drive member and said reaction member, respectively, and wherein said third and fourth pairs of contact surfaces are located in a groove in an outer surface of said sprag member.

11. A sprag system in accordance with claim 10 wherein said peripheral outer surface portions of said drive member and said reaction member respectively include a pair of convex surface segments, said first and second pairs of contact surfaces respectively located on said convex surface segments, and wherein said groove in said sprag member include a pair of convex surface segments and said third and fourth pairs of contact surfaces are respectively located on said pair of convex surface segments.

12. A sprag system in accordance with claim 10 wherein said peripheral outer surface portions of said drive member and said reaction member respectively include a pair of flat surface segments, said first and second pairs of contact surfaces respectively located on said flat surface segments, and wherein said groove in said sprag member includes a pair of convex surface segments and said third and fourth pairs of contact surfaces are respectively located on said pair of convex surface segments.

13. A sprag system in accordance with claim 10 wherein said peripheral outer surface portions of said drive member and said reaction member respectively include a pair of convex surface segments, said first and second pairs of contact surfaces respectively located on said convex surface segments, and wherein said groove in said sprag member includes a pair of concave surface segments and said third and fourth pairs of contact surfaces are respectively located on said pair of concave surface segments.

14. A sprag system in accordance with claim 10 wherein said peripheral outer surface portions of said drive member and said reaction member respectively include a pair of concave surface segments, said first and second pairs of contact surfaces respectively located on said concave surface segments, and wherein said groove in said sprag member includes a pair of convex surface segments and said third and fourth pairs of contact surfaces are respectively located on said pair of convex surface segments.

15. A sprag system in accordance with claim 4 wherein said sprag member comprises a roller member,

16. A sprag system in accordance with claim 4 wherein at least one pair of said pairs of contact surfaces include flat surface segments and wherein an adjoining pair of contact surfaces include curved surface segments.

17. A sprag system in accordance with claim 4 wherein at least one pair of said first and second pairs of contact surfaces are located in grooves in an outer surface of said drive member and said reaction member respectively and wherein said third and fourth pairs of contact surfaces are respectively located on a tapered peripheral portion of said sprag member.

18. A sprag system in accordance with claim 3 wherein at least one of said first and second pairs of contact surfaces comprise a pair of diametrically opposing contact surfaces.

19. A sprag system in accordance with claim 3 wherein at least one of said third and fourth pairs of contact surfaces comprise a pair of diametrically opposing contact surfaces.

20. A sprag system in accordance with claim 1 wherein said drive and reaction members comprise female members and said sprag member comprises a male member.

21. A sprag system in accordance with claim 1 wherein said drive and reaction members comprise male members and said sprag members comprise a female member.

22. A torque coupling sprag system, comprising:

a drive member including a sprag contact surface having a first pair of mutually spaced apart contact surface regions,

a reaction member including a sprag contact surface having a second pair of mutually spaced apart contact surface regions, and

a sprag member located between and biased against said drive member and said reaction member, said sprag member having an outermost perimeter located in a plane normal to an axis of rotation of said sprag member and having a third pair of mutually spaced apart contact surface regions complementary with and in direct contact with said first pair of contact surface regions of said drive member at a location radially inside said outermost perimeter of said sprag member, and having a fourth pair of mutually spaced apart contact surface regions complementary with and in direct contact with said second pair of contact surface regions of said reaction member, and

wherein one pair of contact surfaces of said first and third pairs of contact surfaces and one pair of contact surfaces of said second and fourth pairs of contact surfaces, respectively, comprise curved contact surfaces having a predetermined radius of curvature, and

wherein said sprag member comprises a rotatable member having a radius of rotation and wherein said radius of curvature of said third and fourth pairs of contact surfaces is relatively large relative to said radius of rotation.

23. A sprag system in accordance with claim 22 wherein said first and second pairs of contact surface regions are respectively located in at least one recess formed in said drive member and said reaction member, and wherein said third and fourth pairs of contact surface regions are respectively located on a tapered peripheral outer portion of said sprag member.

24. A sprag system in accordance with claim 22 wherein said first and second pairs of contact surface regions are respectively located on tapered peripheral outer portions of said drive member and said reaction member, and wherein said third and fourth pairs of contact surface regions are respectively located in at least one recess formed in an outer peripheral surface of said sprag member.

25. A sprag system in accordance with claim 22 wherein at least one pair of said first and second pairs of contact surface regions is located in a recess selectively formed in said drive member or said reaction member, and wherein at least one pair of said third and fourth pairs of contact surface regions is selectively located on a tapered peripheral outer portion of said sprag member.

26. A sprag system in accordance with claim 22 wherein at least one pair of said first and second pairs of contact surface regions is located on a tapered peripheral outer portion of said drive member or said reaction member, and wherein at least one pair of said third and fourth pairs of contact surface regions is located in a recess selectively formed in said sprag member.

27. A torque coupling sprag system in accordance with claim 22 wherein said sprag member comprises a member rotatable about said axis of rotation and said reaction member is inclined relative to said drive member and forming an angle therebetween defined by a straight line passing through said axis of rotation and said first and third pairs of contact surfaces and a straight line passing through said axis of rotation and said second and fourth pairs of contact surfaces.