Contactless key switch

Claim 1

A variable inductance key switch assembly for use with an inductance responsive circuit comprising: a push button actuating element digitally operable to at least a first undepressed position and a second depressed position; variable inductor means for resiliently biasing said push button actuating element in said first undepressed position and for providing a first inductance value when said push button actuation element is in said first undepressed position and a second inductance value when said push button actuator is in said second depressed position, said variable inductor means including a compressible coil spring fabricated from a resilient electrically conductive material coupled to said push button actuating element and exerting a resilient biasing force on said push button actuating element for biasing said push button actuating element in said first undepressed position, said push button actuating element being digitally movable to said second depressed position against the resilient biasing force exerted by said coil spring and operative to compress said coil spring to alter the inductance of said coil spring, said coil spring having an inductance value related to the position of said actuating element; means for supporting said push button actuating element and said coil spring; and means for providing an electrical connection to said coil spring.