Pushbutton switch

Abstract

A pushbutton, momentary ON switch has a body including a barrel with longitudinally extending internal splines and ways between the splines. A plunger has radially extending lugs in the ways and is longitudinally movable in the barrel. A plurality of longitudinally extending camming teeth on the plunger engage a plurality of longitudinally extending camming teeth on a rotatable ratchet coaxial with the plunger. The ratchet is spring loaded against the plunger. The ratchet has radially extending dogs which fit into the ways when the plunger is retracted and come out of the ends of the ways when the plunger is advanced. A rotatable electrical contact cup connected to the ratchet and electrically connected to an external lead makes or breaks contact with a fixed electrical terminal in the body. The plunger teeth include a leading ramp face and a trailing ramp face wherein the leading ramp face extends a greater distance in the circumferential direction than the trailing ramp face. The asymmetrical teeth permit symmetrical rotation of the ratchet and electrical contacts. In this case, the contacts rotate approximately 22½° in each half of the stroke of the plunger, making contact upon depressing the plunger and breaking contact upon its retraction. Since the plunger teeth each having an apex offset from a centerline of the tooth, they advance the ratchet a sufficient distance that electrical contact between the fixed electrical terminal member and the rotatable electrical contact cup is made substantially simultaneously with a tactile and/or auditory signal from the switch as the plunger advances the ratchet.