Releasable fastener system

• US 20040074062A1
• Filed: 11/26/2002
• Published: 04/22/2004
• Est. Priority Date: 10/19/2002
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Barvosa-Carter, William, Momoda, Leslie A., Browne, Alan L., Johnson, Nancy L., Powell, Bob R. Jr., Stanford, Thomas B. Jr.
• Granted Patent: US 7,146,690 B2
• Time in Patent Office: Days
• US Class Current: 24/442
• CPC Class Codes: A41D 2300/326 using hooks and eyelets
• CPC Class Codes: A44B 18/0003 Fastener constructions A44B18/0023, A44B18/0046 take precedence
• CPC Class Codes: A44B 18/0096 Shape memory materials
• CPC Class Codes: A44D 2203/00 Fastening by use of magnets
• CPC Class Codes: C08L 2201/12 Shape memory
• CPC Class Codes: F16B 2200/77 Use of a shape-memory material
• CPC Class Codes: F16B 2200/81 Use of a material of the hooks-and-loops type
• CPC Class Codes: F16B 2200/83 Use of a magnetic material
• CPC Class Codes: F16B 5/07 by means of multiple interengaging protrusions on the surfaces, e.g. hooks, coils,
• CPC Class Codes: F16F 2224/045 magnetorheological
• CPC Class Codes: Y10T 24/27 including readily dissociable fastener having numerous, protruding, unitary filaments randomly interlocking with, and simultaneously moving towards, mating structure [e.g., hook-loop type fastener]
• CPC Class Codes: Y10T 24/2783 having filaments constructed from coated, laminated, or composite material
• CPC Class Codes: Y10T 428/24017 Hook or barb

Abstract

A releasable fastener system comprises a loop portion and a hook portion. The loop portion includes a support and a loop material disposed on one side thereof. The hook portion generally includes a support and a plurality of closely spaced upstanding hook elements extending from one side thereof, wherein the plurality of hook elements comprises or incorporates a shape memory alloy fiber. When the hook portion and loop portion are pressed together they interlock to form a releasable engagement. The resulting joint created by the engagement is relatively resistant to shear and pull forces and weak in peel strength forces. Introducing a thermal activation signal to the plurality of hook elements causes a change in shape orientation, flexural modulus property, or a combination thereof that effectively reduces the shear and/or pull off forces in the releasable engagement. In this manner, disengagement of the releasable fastener system provides separation of the hook portion from the loop portion under controlled conditions. Also disclosed herein are processes for operating the releasable fastener system.

Claims

1. A releasable fastener system 10 comprising:

a loop portion 12 comprising a support 16 and a loop material 18 disposed on a surface thereon;

a hook portion 14 comprising a support 20 and a plurality of hook elements 22 disposed on a surface thereon, wherein the plurality of hook elements 22 comprises a shape memory alloy fiber; and

a thermal activation device 24 coupled to the plurality of hook elements 22, the thermal activation device 24 being operable to selectively provide a thermal activation signal to the shape memory alloy fiber and change a shape orientation, a yield strength property, a flexural modulus property, or a combination thereof to reduce a shear force and/or a pull-off force of an engaged hook 14 and loop 12 portion.

2. The releasable fastener system of claim 1, wherein the shape memory alloy fiber comprises nickel-titanium based alloys, indium-titanium based alloys, nickel-aluminum based alloys, nickel-gallium based alloys, copper based alloys, gold-cadmium based alloys, iron-platinum based alloys, iron-palladium based alloys, silver-cadmium based alloys, indium-cadmium based alloys, manganese-copper based alloys, or combinations comprising at least one of the foregoing alloys.

3. The releasable fastener system of claim 1, wherein the shape memory alloy fiber comprises an alloy composition selected to exhibit an austenite phase at an environmental temperature in which the fastener system is disposed and a martensite phase at about a temperature lower than the environmental temperature.

4. The releasable fastener system of claim 1, wherein the shape memory alloy fiber comprises an alloy composition selected to exhibit a martensite phase at an environmental temperature in which the fastener system is disposed and an austentite phase at a temperature greater than the environmental temperature.

5. The releasable fastener system of claim 1, wherein the loop material comprises a shape memory alloy fiber comprising a spiral shape orientation at a martensite temperature condition and a substantially straightened orientation at an austenite temperature condition, and wherein the plurality of hook elements comprise a spiral shape orientation at the martensite temperature condition and a substantially straightened orientation at the austenite temperature condition.

6. The releasable fastener system of claim 1, wherein the plurality of hook elements comprise a shape orientation comprising a J-shaped orientation, a mushroom shape, a knob shape, a multi-tined anchor shape, a T-shape, a spiral shape, or combinations comprising at least one of the foregoing shapes.

7. The releasable fastener system of claim 1, wherein the plurality of hook elements further comprises a polymer coating about the shape memory alloy fiber.

8. The releasable fastener system of claim 7, wherein the polymer comprises an elastomer or a shape memory polymer.

9. The releasable fastener system of claim 7, wherein the hook portion support and the loop portion support comprise an inflexible material.

10. The releasable fastener system of claim 7, wherein the shape memory alloy fiber exhibits a one-way shape memory effect.

11. The releasable fastener system of claim 7, wherein the shape memory alloy fiber exhibits a two-way shape memory effect.

12. A process for operating a releasable fastener system, the process comprising:

contacting a loop portion with a hook portion to form a releasable engagement, wherein the loop portion comprises a support and a loop material disposed on a surface thereon, and wherein the hook portion comprises a support and a plurality of hook elements disposed on a surface, wherein the plurality of hook elements comprises a shape memory alloy fiber;

maintaining constant shear and pull-off forces in the releasable engagement without introducing an energy signal;

selectively introducing the energy signal to the hook elements, wherein the energy signal is effective to change a shape orientation, a yield strength property, a flexural modulus property, or a combination thereof to the plurality of hook elements; and

reducing the shear and/or pull off forces in the releasable engagement.

13. The process according to claim 12, wherein introducing the energy signal comprises heating the shape memory alloy fiber from a martensite phase temperature to an austenite phase temperature.

14. The process according to claim 12, wherein introducing the energy signal comprises cooling the shape memory alloy fiber from an austenite phase temperature to a martensite phase temperature.

15. The process according to claim 12, wherein the shape memory alloy fiber comprises nickel-titanium based alloys, indium-titanium based alloys, nickel-aluminum based alloys, nickel-gallium based alloys, copper based alloys, gold-cadmium based alloys, iron-platinum based alloys, iron-palladium based alloys, silver-cadmium based alloys, indium-cadmium based alloys, manganese-copper based alloys, or combinations comprising at least one of the foregoing alloys.

16. A hook portion for a releasable fastener system comprising:

a support; and

a plurality of hook elements disposed on a surface of the support, wherein the plurality of hook elements comprise a shape memory alloy fiber adapted to change a shape orientation, a yield strength property, a flexural modulus property, or a combination thereof, upon receipt of an activation signal.

17. The hook portion of claim 16, wherein the shape memory alloy fiber comprises nickel-titanium based alloys, indium-titanium based alloys, nickel-aluminum based alloys, nickel-gallium based alloys, copper based alloys, gold-cadmium based alloys, iron-platinum based alloys, iron-palladium based alloys, silver-cadmium based alloys, indium-cadmium based alloys, manganese-copper based alloys, or combinations comprising at least one of the foregoing alloys.

18. The hook portion of claim 16, wherein the plurality of hook elements comprise a shape orientation adapted for engagement with a loop material at a martensite phase temperature and a substantially straightened orientation at an austenite phase temperature.

19. The hook portion of claim 16, wherein the plurality of hook elements further comprise a polymer coating about the shape memory alloy fiber, wherein the polymer and a thickness of the polymer are selected to increase the yield strength property, the flexural modulus property, or the combination thereof.

20. A releasable fastener system comprising:

a loop portion comprising a support and a loop material disposed on a surface thereon, wherein the loop portion comprises shape memory alloy fibers in a spiral shape orientation at a martensite phase temperature and a substantially straightened orientation at an austenite phase temperature;

a hook portion comprising a support and a plurality of hook elements disposed on a surface, wherein the plurality of hook elements comprises shape memory alloy fibers in the spiral shape orientation at the martensite phase temperature and a substantially straightened orientation at the austenite phase temperature; and

means for changing the shape orientation, the yield strength property, the flexural modulus property, or the combination thereof of the hook elements to reduce a shear force and/or a pull-off force of an engaged hook and loop portion.

21. A releasable fastener system comprising:

a loop portion comprising a support and a loop material disposed on a surface thereon, wherein the loop portion comprises shape memory alloy fibers in a spiral shape orientation at an austenite phase temperature and a reduction in yield strength and/or flexural modulus properties at a martensite phase temperature;

a hook portion comprising a support and a plurality of hook elements disposed on a surface, wherein the plurality of hook elements comprises shape memory alloy fibers in the spiral shape orientation at the austenite phase temperature and the reduction in yield strength and/or flexural modulus properties at the martensite phase temperature; and

means for changing a temperature of the plurality of hook elements and the loop material upon demand to reduce a shear force and/or a pull-off force of an engaged hook and loop portion.

22. A releasable fastener system comprising:

a loop portion comprising a support and a loop material disposed on a surface thereon;

a hook portion comprising a support and a plurality of hook elements disposed on a surface thereon, wherein the plurality of hook elements comprises a shape memory alloy sleeve coupled to a core material; and

a thermal activation device coupled to the plurality of hook elements, the thermal activation device being operable to selectively provide a thermal activation signal to the shape memory alloy sleeve and change a shape orientation, a yield strength property, a flexural modulus property, or a combination thereof to reduce a shear force and/or a pull-off force of an engaged hook and loop portion.

23. The releasable fastener according to claim 22, wherein the core material comprises a superelastic shape memory alloy, spring steel, or a bonded carbon fiber.

24. The releasable fastener according to claim 22 wherein the shape memory alloy fiber comprises nickel-titanium based alloys, indium-titanium based alloys, nickel-aluminum based alloys, nickel-gallium based alloys, copper based alloys, gold-cadmium based alloys, iron-platinum based alloys, iron-palladium based alloys, silver-cadmium based alloys, indium-cadmium based alloys, manganese-copper based alloys, or combinations comprising at least one of the foregoing alloys.

25. A releasable fastener system comprising:

a loop portion comprising a support and a loop material disposed on a surface thereon;

a hook portion comprising a support and a plurality of hook elements disposed on a surface thereon, wherein the plurality of hook elements comprises a sleeve coupled to a shape memory alloy core material; and

a thermal activation device coupled to the plurality of hook elements, the thermal activation device being operable to selectively provide a thermal activation signal to the shape memory alloy core material and change a shape orientation, a yield strength property, a flexural modulus property, or a combination thereof to reduce a shear force and/or a pull-off force of an engaged hook and loop portion.

26. The releasable fastener according to claim 26, wherein the sleeve comprises a superelastic shape memory alloy, spring steel, or a bonded carbon fiber.

27. The releasable fastener according to claim 26, wherein the shape memory alloy core material comprises nickel-titanium based alloys, indium-titanium based alloys, nickel-aluminum based alloys, nickel-gallium based alloys, copper based alloys, gold-cadmium based alloys, iron-platinum based alloys, iron-palladium based alloys, silver-cadmium based alloys, indium-cadmium based alloys, manganese-copper based alloys, or combinations comprising at least one of the foregoing alloys.

28. A releasable fastener system comprising:

a loop portion comprising a support and a loop material disposed on a surface thereon;

a hook portion comprising a support and a plurality of hook elements disposed on a surface thereon, wherein the plurality of hook elements comprises an inflexible sleeve and a shape memory alloy fiber disposed within the sleeve, wherein one end of the shape memory alloy fiber is fixedly attached to the support surface and an other end is fixedly attached to an elastic hook, wherein the elastic hook extends from the sleeve in an amount effective to engage the loop material; and

a thermal activation device coupled to the plurality of hook elements, the thermal activation device being operable to selectively provide a thermal activation signal to the shape memory alloy fiber and change a length dimension and retract the elastic hook into the sleeve and disengage the elastic hook from the loop material.

29. The releasable fastener system according to claim 28, wherein the elastic hook comprises a superelastic shape memory alloy, spring steel, or a polymer.

30. The releasable fastener system according to claim 28, wherein the inflexible sleeve comprises steel, an aluminum or aluminum alloy, brass, copper and copper alloys, or a polymer.

31. The releasable fastener system according to claim 28 wherein the shape memory alloy fiber comprises nickel-titanium based alloys, indium-titanium based alloys, nickel-aluminum based alloys, nickel-gallium based alloys, copper based alloys, gold-cadmium based alloys, iron-platinum based alloys, iron-palladium based alloys, silver-cadmium based alloys, indium-cadmium based alloys, manganese-copper based alloys, or combinations comprising at least one of the foregoing alloys.

32. The releasable fastener system according to claim 28, wherein the other end of the shape memory alloy fiber is attached to a plurality of elastic hooks.

33. A releasable fastener system comprising:

a loop portion comprising a support and a loop material disposed on a surface thereon;

a hook portion comprising a support and a plurality of hook elements disposed on a surface thereon, wherein each one of the plurality of hook elements comprises one or more shape memory alloy fibers combined with one or more elastic fibers or elements;

and a thermal activation device coupled to the plurality of hook elements, the thermal activation device being operable to selectively provide a thermal activation signal to the shape memory alloy fiber and change a shape orientation, a yield strength and/or flexural modulus property, or a combination of these properties of the plurality of hook elements to reduce a shear force and/or a pull-off force of an engaged hook and loop portion.