Torque transducing systems for impact tools and impact tools

Abstract

A torque transducing system for an impact tool such as an impact wrench incorporates a housing, bearings in the housing, a rotatable shaft journalled in the bearings, the shaft having a torque receiving input end and an output end supplying torque for a workpiece, a torque transducing gauge on the shaft intermediate the input and the output end for providing a first signal responsive to torque, circuitry on the rotatable shaft for modulating the first signal to a second signal, structure on the shaft for supplying current to the gauge and modulating circuitry and additional structure for transmitting the second signal, further structure on the housing for receiving the transmitted second signal, and circuitry for converting the second received signal to provide an output indicative of torque. Current can be supplied to and a signal can be obtained from the signal modulating circuitry by providing a plurality of brush assemblies mounted on the housing and the rotatable shaft has corresponding sliprings, one pair of said sliprings forming the aforesaid structure for supplying current to the torque transducing gauge and one slipring forming the additional structure for transmitting the second signal, the modulating circuitry including an amplifier to permit transmission of the second signal to its brush assembly with a proportionately low signal loss.