Patent ID: 8173915

Claim:
An ignition key switch apparatus with an improved snap action mechanism, comprising: a lock cylinder having an opening and to slidably receive a key therein; an anchor disposed within and coupled to the lock cylinder in cantilever fashion, and having a fixed end and a free end, the fixed end coupled to the lock cylinder; a pre-loaded snap spring disposed within the lock cylinder and having a fixed end attached to the fixed end of the anchor, an intermediate portion coupled to the free end of the anchor, and a free end having a movable contact attached thereto, wherein said pre-loaded snap spring generates an instantaneous movement from an open position to a closed position and vice versa upon application or removal of a load to reduce an effect of arcing on a plurality of contacts; a plunger disposed within the lock cylinder and engaging the snap spring, the plunger configured to selectively implement linear movement to a plurality of positions to thereby apply or remove the load to the snap spring, and a cam disposed within said lock cylinder and configured to convert rotary motion at a key interface to the linear movement of said plunger to effectuate the snap spring actuation, wherein said snap spring ensures said movable contact does not remain in any intermittent position other than at least two extreme positions at any position of said plunger.