Multi-contact push-button switch and plural embodiment for keyboard switch assembly

摘要

A push button switch has a spring contact plate and a circuit board in superposed position. The spring contact plate has one or more switch positions, each switch position comprising a prestressed domed portion surrounded by a flat sheet portion. The domed portion includes a central portion and radial webs connecting the central portion to the flat sheet portion. Spring contacts extend radially from the central portion, each contact between a pair of webs. The domed portion is prestressed to assume a stable position offset upwards from a plane coincident with the flat sheet portion, and the webs each have an upwardly bent portion at the junction with the flat sheet portion. A push button acts on the central portion and pressure on the push button causes the central portion to snap through the plane of the flat sheet portion, with the spring contacts contacting contact areas on the circuit board. Release of the push button enables the domed portion to snap back to the stable position.