Coil spring for key switch

摘要

A key switch is disclosed which employs a coil spring formed of a spring element and which has a smaller-diameter portion, a conical portion joined to one end of the smaller-diameter portion, and a larger-diameter portion joined to the other end of the smaller-diameter portion. The smaller-diameter portion has the spring element coiled at a relatively small diameter. The conical portion has the spring element extending coiled so as to increase its diameter progressively toward an open end thereof. The larger-diameter portion has a diameter larger than the diameter of the smaller-diameter portion. The conical portion is maintained under compression and the small-diameter portion is maintained in proximity to a contact area by elements of the key switch to provide a linearly increasing depression force for the key switch.