Push button switch

Claim 1

A push button switch having a resistance value varying in response to variations in a pressure applied thereto, said push button switch comprising: a printed circuit board having electrode patterns; a pressure-sensitive resistance element to be pressed against said electrode patterns, said pressure-sensitive resistance element comprising a conductive layer coated with a layer of solidified pressure-sensitive conductive paste and molded together by press curing under heat; an insulated push button comprising a pressing surface at a base portion thereof, two projection portions at an upper portion of said insulated push button, and a flange portion fixed to said printed circuit board, said conductive layer of said pressure-sensitive resistance element being fixed to said pressing surface and being spaced from said electrode patterns by a predetermined gap, and said two projection portions being separated by a thin portion for allowing vertical movement of said insulated push button; a button cover having two protrusions adjacent in one-to-one correspondence to said two projection portions, either of said protrusions exclusively pressing against one of said projection portions when said button cover is pressed by a user; a shaft between said two projection portions for movably supporting said button cover on said printed circuit board, said button cover being movable in a seesawing motion; and a supporting member fixed to said printed circuit board such that said flange portion is fixedly sandwiched between said supporting member and said printed circuit board.