Clamp holds members in rotatably adjusted position

Abstract

A locking device is provided for a potentiometer dial and knob which are disposed on the front panel of a printed circuit board. There is a radial flange on the shaft of the potentiometer dial and knob. The base or non-turning portion of the potentiometer is fixedly disposed on the panel and is fixedly disposed on the printed circuit board. A pressure plate member having an opening therein is disposed around the rotatable shaft. The flange may thus abut the pressure plate to prevent substantial axial motion of the shaft which might cause the potentiometer base to be loosened from the printed circuit board. A movable locking member having an opening is disposed around the outer portion of the shaft so that the flange is disposed between the pressure plate and the locking member. There are second aligned openings in each of the locking member and the pressure plate through which a screw protrudes. The threaded base of the screw is rotatably disposed in a correspondingly threaded hole in the panel. As the screw is turned, the movable locking member is moved toward the flange thus pressing against the flange causing the flange in turn to be caught between the locking member and the pressure plate. This locks the potentiometer shaft at a fixed angular position. The lock and potentiometer may be utilized on a solid state control for an automatic transfer switch.