Patent ID: 6587056
Filing Date: 2003-07-01
Classification: H01H,H03K,H05K

Abstract:
A rheostat for a systems control panel having a front plate and a front PWA spaced a predetermined distance from the front plate, said rheostat comprising a rotary operating knob, a housing having at least one cylinder, a piston mounted in the cylinder and carrying a magnet, the piston being interconnected with the operating knob such that rotation of the knob moves the piston in the cylinder toward and away from the PWA, and the PWA having a Hall effect sensor mounted for detecting movement of the piston relative to the PWA, in which the operating knob includes a cam disk rotatable with the remainder of the operating knob, the cam disk having a helical cam slot, the piston having a member for riding in the cam slot such that rotation of the operating knob moves the piston toward and away from the PWA, the degree of travel of the piston for a given amount of rotation of the operating knob being predetermined by the slope of the cam slot.