Elastomeric key switch actuator

摘要

A key switch and resilient actuator assembly that includes an electrical switching region and a hollow open ended actuator cover of elastomeric material overlaying the switching region with the open end of the actuator cover in surrounding relationship with the switching region. The actuator cover includes a first wall portion shaped to provide substantially linear resistive force during compression displacement of the cover toward the switching region and to provide substantially linear restoring force during expansion displacement of the actuator cover away from the switching region. The actuator cover further includes a second wall portion shaped to undergo buckling toward the switching region at a predetermined compression displacement and to undergo unbuckling away from the switching region at a predetermined expansion displacement that is smaller in total displacement than the predetermined compression displacement. The actuator cover also includes an interior portion positioned and sized to move into the switching region at the buckling of the second wall portion and to move out of the switching region at the unbuckling of the second wall portion.