Abstract: In a power operated torque tool, the pressure-fluid feed is controlled by a valve which opens to start the tool, and closes to stop it. This valve is mounted on the end of a push-rod which extends along the axis of the tool. The tool also has a clutch which disengages on reaching a predetermined torque, and at the same time releases a grip on the push-rod, so that the valve can move to close the feed to the tool motor, and thus to stop the tool. The grip on the push-rod is exerted by a group of balls held in a sleeve and pushed against the rod by a tube with a tapered internal wall which surrounds the sleeve. The balls are pushed against the taper by a light spring, which is considerably weaker than the spring which holds the clutch in engagement.