Keyswitch

Claim 1

A keyswitch comprising: a hollow insulative base having an open top side, a bottom wall and four integrally formed side walls extending upward from a periphery of said bottom wall and four circumferentially equidistant vertical guide slots formed in inner surfaces of said side walls, each of said guide slots being disposed between adjacent two of said side walls, each of said side walls including two vertical ribs extending from an inner surface thereof to define a guideway therebetween, said bottom wall including four holes formed therethrough in alignment with said guideways, and a plurality of horizontal ribs extending from an upper surface of said bottom wall; a pair of spaced-apart electrode elements each having a body placed on said bottom wall of said base, and two legs extending downward from said body to pass through an adjacent two of said holes; a conductive coil spring, shaped in the form of a truncated cone with turns of different diameters which gradually decrease in size from bottom to top thereof, disposed in said base in such a manner that a lowermost turned portion of said spring is supported on said horizontal ribs and spaced from said electrode elements; an insulative cover sealing said open side of said base and having a passage formed through said cover; and a depressible, insulative push-button type actuator including four connecting rods extending radially and outwardly from a peripheral surface of a lower end portion thereof, and four sliding blocks respectively secured to outer ends of said connecting rods and slidable in said guide slots of said base; whereby, when said actuator is depressed to compress said spring, a turned portion of an upper portion of said spring moves through said lowermost turned portion so as to come into bridging contact with said electrode elements and establish a conductive path between said electrode elements.