Magnetorheological nanocomposite elastomer for releasable attachment applications

• US 7,430,788 B2
• Filed: 03/30/2006
• Issued: 10/07/2008
• Est. Priority Date: 10/19/2002
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Ulicny, John C., Golden, Mark A., Ottaviani, Robert A.
• Primary Examiner(s): Lavinder; Jack W.
• Application Number:
  US11/393,318
• Publication Number:
  US 20060168780A1
• Time in Patent Office: 922 Days
• Field of Search: 244/42, 244/46, 244/50, 244/51, 244/52, 244/48, 243/04
• US Class Current: 24/442
• 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: F16F 1/3605 characterised by their material F16F1/362, F16F1/364, F16F1/366, F16F1/37 take precedence; composition of macromolecular compounds in general C08L
• 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 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 whereas the hook portion includes a support and a plurality of closely spaced upstanding hook elements extending from one side thereof. 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. The hook elements are formed of a magnetorheological elastomer that provides a change in shape orientation and/or flexural modulus of the hook elements. In this manner, the shape orientation and/or flexural modulus of the hook elements can be remotely changed to provide a reduction or magnification in the shear and/or pull-off forces in addition to providing variable damping capabilities to the fastener system.

Claims

1. 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 magnetorheological elastomer adapted to change a shape orientation and/or a flexural modulus upon receipt of a magnetic signal, wherein the magnetorheological elastomer comprises ferromagnetic or paramagnetic particulates in an elastomeric material.

2. The hook portion according to claim 1, wherein the support comprises a metal, a plastic, a fabric, or a combination comprising at least one of the foregoing materials.

3. The hook portion according to claim 1, wherein the hook elements comprise a shape comprising a J-shaped orientation, an L-shape, a mushroom shape, a knob shape, a multi-tined anchor shape, a T-shape, a spiral shape, and combinations comprising at least one of the foregoing shapes.

4. The hook portion according to claim 1, wherein the elastomeric material comprises poly-alpha-olefins, natural rubber, silicone, polybutadiene, polyethylene, polyisoprene, polyurethane, or combinations comprising at least one of the foregoing polymeric materials.

5. The hook portion according to claim 1, wherein the particulates comprise iron alloys, nickel alloys, manganese alloys, cobalt alloys, or compounds comprising oxides, chlorides, sulfates, sulfides, or hydrates of cerium, chromium, cobalt, dysprosium, erbium, europium, gadolinium, holmium, iron, manganese, neodymium, nickel, praesodymium, samarium, terbium, titanium, uranium, vanadium, or yttrium.

6. The hook portion according to claim 1, wherein the particulates comprise nanometer sized particles.

7. The hook portion according to claim 1, wherein the shape orientation of the plurality of hook elements changes from an inverted J-shaped orientation to a substantially straightened orientation upon receipt of the activation signal.