Digital beam torque wrench

Abstract

A digital beam-type torque wrench has a main beam and a stationary beam having a distal end thereof fixedly attached at or near a distal end of the main beam. A sensing assembly is disposed generally at a proximal end of the main beam and includes a displacement sensing element carried by the proximal end of the stationary beam and a sensing element actuator disposed on said main beam. The sensing element actuator and sensing actuator cooperate to generate a variable output voltage, whose magnitude is proportional to the amount of flexure of the main beam upon application of torque upon a rotating element by the wrench. In one embodiment, the sensing assembly comprises a potentiometric rotary position sensor including an arcuate rack gear coupled to the main beam and engaged with a pinion gear coupled to the stationary beam, with rotation of the pinion gear in turn causing rotation of a potentiometer. The voltage output from the potentiometer thus varies in proportion to the amount of displacement (flexure) of the main beam relative to the stationary beam. In an alternative embodiment, the sensing element comprises a ratiometric Hall-effect sensor disposed on the proximal end of the stationary beam and a magnetic actuating element disposed on the main beam.