Magnetorheological nanocomposite elastomer for releasable attachment applications

• US 7,020,938 B2
• Filed: 04/15/2004
• Issued: 04/04/2006
• 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 (Motors Liquidation Co. GUC Trust)
• Inventors: Ulicny, John C., Golden, Mark A., Ottaviani, Robert A.
• Primary Examiner(s): Lavinder, Jack W.
• Application Number:
  US10/826,200
• Publication Number:
  US 20040194261A1
• Time in Patent Office: 719 Days
• Field of Search: 244/42, 244/46, 244/50, 244/51, 244/52, 244/48, 243/04, 428/100, 267/140.14, 267/140.15, 267/136, 188/267, 188/267.2
• 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 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, wherein the plurality of hook elements comprises a magnetorheological elastomer adapted to change a shape orientation and/or flexural modulus in response to a magnetic signal; and

a vibration sensor in operative communication with a selected one of the hook and loop portions, wherein the sensor detects a frequency and magnitude of a vibration to adjusts a magnitude of the magnetic signal, wherein the change in magnitude of the magnetic signal changes a shape orientation and/or flexural modulus of the plurality of hook elements to reduce a shear force and/or a pull-off force of an engaged hook and loop portion and to provide variable damping to the fastener system.

2. The system of 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 system of claim 1, wherein the plurality of 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 system of claim 1, wherein the magnetorheological elastomer comprises ferromagnetic or paramagnetic particulates in an elastomeric material, 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 system of claim 1, wherein the loop portion and the hook portion from an interlocking system for a duration of a magnetic signal and disengages in an absence of the magnetic signal.

6. The system of claim 1, wherein the shear force and/or pull off forces increases by increasing the magnitude of the magnetic signal.