ELECTRICALLY RELEASABLE HOOK AND LOOP FASTENER

An electrically releasable form of hook and loop fastener allows one half of the fastener to release from the other half without applying direct physical force to either half. The hook elements of the fastener are formed of a shape-memory alloy material such as commercially available Ninitol. Release of the hook half of the fastener from the loop half is accomplished by passing an electrical current through the shape-memory alloy material to straighten the hooks so that they release their engagement with the loops. The flow of electricity through the hook half energizes the Ninitol material to change its shape, either expanding or contracting in length; the change in shape is made to act against another length of material that remains fixed in length or changes shape in an opposite direction so as to cause the hook shape to straighten toward a rod shape. Upon termination of the flow of electrical energy, the hooks return to their hook shape, ready for re-engagement with the loops upon conventional mating of the two halves of the fastener. Release and re-engagement can be repeated, substantially indefinitely.