Roller cam buckle

• US 20040163216A1
• Filed: 02/21/2003
• Published: 08/26/2004
• Est. Priority Date: 02/21/2003
• Status: Active Grant

• Current Assignee: Eric Simonson, Roger Simonson
• Original Assignee: Eric Simonson, Roger Simonson
• Inventors: Simonson, Eric, Simonson, Roger
• Granted Patent: US 6,877,189 B2
• Time in Patent Office: Days
• US Class Current: 24/68CD
• CPC Class Codes: B60P 7/083 Tensioning by repetetive movement of an actuating member
• CPC Class Codes: Y10T 24/2175 Cargo tie down
• CPC Class Codes: Y10T 24/40 Buckles
• CPC Class Codes: Y10T 24/4016 Pivoted part or lever

Abstract

A method and apparatus for reducing friction in a cam buckle for tightening a strap. The cam buckle includes a frame, a brake member, a roller member, a biasing element and a webbed strap. The brake member includes a serrated surface and is rotatably coupled to the frame and pivotal about a first axis. The roller member is rotatably coupled to the frame about a second axis, wherein the first axis and the second axis are substantially parallel to each other. The biasing element is operable to bias the serrated surface of the brake member toward the roller member. The webbed strap is formed from a polymeric material and is operable to be biased between the serrated surface and the roller member so that the brake member biases the webbed strap against the roller member. With this arrangement, when the webbed strap is placed in tension, such tension is maintained by preventing movement of the webbed strap in one direction and allowing movement in a second direction to increase the tension. The roller member is operable to rotate with movement of the webbed strap in the second direction to increase the tension in the webbed strap.

Claims

1. A cam buckle configured to reduce friction for tightening a strap, the cam buckle comprising:

a frame;

a brake member at least partially having a contoured friction surface, said brake member rotatably coupled to said frame and pivotal about a first axis;

a roller member rotatably coupled to said frame about a second axis, said second axis substantially parallel with said first axis;

a biasing element operable to bias said brake member toward said roller member and against the strap; and

a webbed strap having a polymeric material and operable to be biased between said contoured friction surface and said roller member so that said brake member urges said webbed strap against said roller member when placed in tension so as to maintain said tension by preventing movement of said webbed strap in one direction and allowing movement in a second direction to increase said tension;

wherein said roller member is operable to rotate with movement of said webbed strap in said second direction to increase said tension in said webbed strap.

2. The cam buckle of claim 1, wherein said roller member comprises a shaft coupled to said frame and a cylinder rotatable around said shaft.

3. The cam buckle of claim 2, wherein said roller member includes bearings disposed in said cylinder and operable to rotate with said cylinder around said shaft.

4. The cam buckle of claim 1, wherein said roller member comprises a cylinder with recesses defined in opposing ends of said cylinder, said cylinder rotatable around nubs extending from and disposed in said frame.

5. The cam buckle of claim 1, wherein said tension in said strap is substantially limited only by rolling contact friction in said roller member with respect to a pulling force applied to said webbed strap in said second direction.

6. The cam buckle of claim 1, wherein the roller member comprises a substantially smooth surface configured to be at least partially in contact with the webbed strap.

7. The cam buckle of claim 1, wherein said roller member comprises an abrasive surface configured to be at least partially in contact with the webbed strap.

8. The cam buckle of claim 1, wherein said contoured friction surface of said brake member comprises serrations slantedly oriented so that said webbed strap passes over said serrations in said second direction and is prevented from passing over said serrations in said first direction.

9. The cam buckle of claim 1, wherein said roller member comprises a concave surface configured to be at least partially in contact with the webbed strap.

10. The cam buckle of claim 1, wherein said roller member comprises a convex surface configured to be at least partially in contact with the webbed strap.

11. The cam buckle of claim 1, wherein said roller member comprises a grooved surface configured to be at least partially in contact with the webbed strap.

12. The cam buckle of claim 11, wherein said grooved surface collectively comprises a pattern configuration operable to substantially maintain a centered position of said webbed strap during movement of said webbed strap in said second direction.

13. The cam buckle of claim 1, wherein said frame includes tabs extending inward at opposing positions from said frame to substantially maintain a centered position of said webbed strap during movement of said webbed strap in said second direction.

14. The cam buckle of claim 1, wherein said webbed strap comprises a weaved high-strength polymeric material.

15. The cam buckle of claim 1, wherein said webbed strap comprises at least one of a polypropylene material and a polyethylene material.

16. The cam buckle of claim 1, wherein said brake member includes a second roller having unidirectional rotation configured to rotate with movement of said webbed strap in said second direction to increase said tension in said webbed strap.

17. The cam buckle of claim 16, wherein said brake member includes a sprag member operable with said second roller to provide said unidirectional rotation so as to prevent movement of said webbed strap in said one direction and to maintain said tension in said webbed strap.

18. A cam buckle configured to reduce friction for tightening a webbed strap, the cam buckle comprising:

a frame;

a brake member movably coupled to said frame;

a roller member rotatably coupled to said frame; and

a biasing element operable to bias said brake member toward said roller member with the webbed strap therebetween;

wherein said roller member acts in conjunction with said brake member to capture the webbed strap between said brake member and said roller member when the webbed strap is placed in tension by preventing movement of the webbed strap in one direction and allowing movement in a second direction; and

wherein said roller member is operable to rotate with movement of the webbed strap in said second direction to increase said tension in the webbed strap.

19. The cam buckle of claim 18, wherein said brake member includes a second roller having unidirectional rotation configured to rotate with movement of the webbed strap in said second direction to increase said tension in the webbed strap.

20. The cam buckle of claim 19, wherein said brake member includes a sprag member operable with said second roller to provide said unidirectional rotation so as to prevent movement of said webbed strap in said one direction and to maintain said tension in the webbed strap.

21. A method of tightening a strap with a clamp buckle, the method comprising:

providing a roller cam buckle having a frame, a brake member and a roller member, said brake member and said roller member rotatably coupled to said frame and said brake member operable to pivotally bias against said roller member;

providing a webbed strap formed from a polymeric material;

inserting said webbed strap between said brake member and said roller member so that said brake member operably biases said webbed strap against said roller member between a first portion and a second portion of said webbed strap;

securing said first portion of said webbed strap to a load;

securing one portion of a secondary strap to said load, said secondary strap coupled to said frame at another portion of said secondary strap;

pulling said second portion of said webbed strap with a pulling force over said roller member so that said roller member rotates with movement of said webbed strap from said pulling force; and

obtaining a tension force in said first portion of said webbed strap from said movement of said pulling force on said second portion of said webbed strap over said roller member rotating with said movement of said webbed strap.

22. The method of claim 21, further comprising maintaining said tension force from said brake member biasing said webbed strap against said roller member.

23. The method of claim 21, further comprising the step of providing said brake member with a second roller having unidirectional rotation.

24. The method of claim 23, wherein said pulling comprises pulling said second portion of said webbed strap with said pulling force so that said second roller rotates with said movement of said webbed strap from said pulling force.

25. The method of claim 24, wherein said obtaining comprises obtaining said tension force in said first portion of said webbed strap from said movement of said webbed strap via said pulling force on said second portion of said webbed strap with said second roller rotating with said movement of said webbed strap.

26. The method of claim 25, further comprising maintaining said tension force from said second roller biasing said webbed strap against said roller member.