Electrostatically releasable fastening system and method of use

• US 20040074067A1
• Filed: 02/04/2003
• 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 (General Motors Company)
• Inventors: Johnson, Nancy L., Namuduri, Chandra Sekhar, Browne, Alan Lampe
• Granted Patent: US 6,944,920 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 18/0007 in which each part has similar elements
• CPC Class Codes: A44B 18/0096 Shape memory materials
• CPC Class Codes: A44D 2203/00 Fastening by use of magnets
• CPC Class Codes: B64C 33/02 Wings; Actuating mechanisms therefor
• 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 fastening system comprises a loop portion comprising a loop material, a hook portion comprising a plurality of hook elements, and an actuation device disposed in electrical communication with the loop portion and the hook portion. The actuation device is operable to provide electrostatic charges to the loop material and the hook elements. A method of operating a releasable fastening system comprises contacting a loop portion to a hook portion to form a releasable engagement wherein the loop portion comprises a first electrically conductive sheet and a loop material disposed at the first electrically conductive sheet and wherein the hook portion comprises a second electrically conductive sheet and a hook element disposed at the second electrically conductive sheet, maintaining constant shear and pull forces between the loop and hook portions, and introducing electrostatic charges of opposite polarities to the loop and hook portions to enhance the engagement of the hook and loop portions and of similar polarities to weaken the engagement of the hook and loop portions.

Claims

1. A releasable fastening system, comprising:

a loop portion comprising a loop material;

a hook portion comprising a plurality of hook elements; and

an actuation device disposed in electrical communication with said loop portion and said hook portion, said actuation device being operable to provide a first electrostatic charge to said loop material and a second electrostatic charge to said hook elements.

2. The releasable fastening system of claim 1, further comprising,

a first insulative coating disposed on said loop material of said loop portion, said first insulative coating being configured to inhibit the migration of said first electrostatic charge from said loop material, and

a second insulative coating disposed on said hook material of said hook portion, said second insulative coating being configured to inhibit the migration of said second electrostatic charge from said hook elements.

3. The releasable fastening system of claim 1, wherein said actuation device comprises,

a first power source disposed in electrical communication with said loop portion, and

a second power source disposed in electrical communication with said hook portion.

4. The releasable fastening system of claim 1, wherein said electrostatic charges are of opposing polarities to effect the mutual attraction of said loop portion and said hook portion.

5. The releasable fastening system of claim 1, wherein said electrostatic charges are of the same polarities to effect the mutual repulsion of said loop portion and said hook portion.

6. A releasable fastening system, comprising:

a loop portion comprising a loop material, a first electrically conductive sheet on which said loop material is supported or attached, a first insulating layer disposed on said first electrically conductive sheet, and a loop portion support member disposed on said first insulating layer;

a hook portion comprising a hook element mechanically engageable with said loop material, a second electrically conductive sheet at which said hook element is supported, a second insulating layer disposed at said second electrically conductive sheet, and a hook portion support member disposed at said second insulating layer; and

an actuation device disposed in electrical communication with said loop portion and said hook portion, said actuation device being configured to impart an electrostatic charge of a first polarity to said loop material and a second polarity to said hook elements.

7. The releasable fastening system of claim 6, further comprising,

a first insulative coating disposed on said loop material and said first electrically conductive sheet, and

a second insulative coating disposed on said hook element and said second electrically conductive sheet.

8. The releasable fastening system of claim 6, wherein said loop material comprises an arrangement of loops configured to define a pile, each of said loops comprising one or more strands.

9. The releasable fastening system of claim 6, wherein said loop material comprises a plastic, a fabric, a metal, or a combination of the foregoing materials.

10. The releasable fastening system of claim 6, wherein said hook element comprises a J-shaped orientation, a mushroom shape, a knob shape, an anchor shape, a T-shape, a spiral shape, or a combination comprising at least one of the foregoing shapes.

11. The releasable fastening system of claim 6, wherein said hook element comprises a plastic, a fabric, a metal, or a combination of the foregoing materials.

12. The releasable fastening system of claim 6, wherein said actuation device comprises:

a first power source disposed in electrical communication with said first electrically conductive sheet through a first switching device, and

a second power source disposed in electrical communication with said second electrically conductive sheet through a second switching device.

13. The releasable fastening system of claim 12, further comprising a third switching device disposed in electrical communication with a cathode of said second power source.

14. The releasable fastening system of claim 12 wherein said first and second power sources are direct current power sources.

15. A method of operating a releasable fastening system, comprising:

contacting a loop portion to a hook portion to form a releasable engagement, wherein said loop portion comprises a first electrically conductive sheet and a loop material attached to or disposed on said first electrically conductive sheet, and wherein said hook portion comprises a second electrically conductive sheet and a hook element attached to or disposed on said second electrically conductive sheet;

maintaining constant shear forces and constant pull-off forces between said loop portion and said hook portion;

introducing a first electrostatic charge to said loop portion; and

introducing a second electrostatic charge to said hook portion.

16. The method of claim 15, wherein said introducing said first and second electrostatic charges to said loop portion and said hook portion comprises supplying currents to said loop portion and said hook portion.

17. The method of claim 16, wherein said supplying currents to said loop portion and said hook portion comprises electrostatically charging said loop portion and said hook portion with opposite polarities to effect the mutual attraction of said loop portion and said hook portion.

18. The method of claim 16, wherein said supplying currents to said loop portion and said hook portion comprises electrostatically charging said loop portion and said hook portion with similar polarities to effect the mutual repulsion of said loop portion and said hook portion.

19. The method of claim 16, further comprising introducing a signal to said hook portion to cause a change in a shape orientation, a flexural modulus property, or a combination of the foregoing to a hook element of said hook portion.