Switch assembly for variable resistor

Claim 1

A switch assembly for use with a variable resistor formed by at least one rotary variable resistance device having a common operation rod adapted to be rotated for actuating each said rotary variable resistance device and slid axially within said variable resistor for actuating the switch assembly; comprising a substrate held posteriorly to said variable resistor and carrying a stationary contact; an actuator held to an end portion of said operation rod and spaced from said stationary contact; and a moveable contact formed of a resilient material and having a central portion shaped as a dome extending away from said stationary contact and a lead portion extending from said central portion, said lead portion being connected with said substrate, said central portion engaging said actuator while resiliently urging it continually away from said stationary contact to bias said operation rod continually in its axial outer position and adapted upon inward axial movement of said operation rod to invert the shape of said central portion abruptly to engage said central portion with said stationary contact and to dis-engage the central portion from said stationary contact abruptly upon release of said operation rod.