Pneumatic nut-runner having a torque sensing device

Claim 1

A nut-running tool comprising a housing, a stationary block supporting the housing for relative rotation, motor-driven gearing in the housing having an output spindle and having a ring gear fixed to the housing so that torque of the gearing is transmitted to both the housing and the spindle in a particular direction, a torque arm fixed to the housing and extending laterally therefrom, a signal circuit control switch, a bracket supporting the switch to the block, and loss-motion linkage means arranged between the switch and the torque arm adapted upon an initial predetermined angular movement of the torque arm in said direction to take up the loss-motion in the linkage and adapted upon subsequent further predetermined angular movement of the torque arm to cause actuation of the switch, wherein the lossmotion linkage comprises: a pushrod slidable in the bracket, a lever pivoted in the bracket having one end abutting the torque arm and having an edge underlying a bottom end of the pushrod, a switch rod slidable in the bracket disposed in axial alignment with the switch and with the pushrod, the pushrod having a lossmotion connection with the switch rod arranged so that upon a predetermined initial angular movement of the torque arm the pushrod is caused to move relative to the switch rod until the loss-motion is taken up and upon subsequent further angular movement of the torque arm the pushrod and switch rod are caused to move as a unit relative to the switch.