Threading attachment

Claim 1

A threading attachment for connection to a continuously turning rotary power takeoff for providing a thread on a workpiece positioned axially aligned with the power takeoff comprising, a lead screw axially aligned between the rotary power takeoff and the workpiece, longitudinally slidable engaging means including a key and an elongated keyway longer than the key between the lead screw and the power takeoff whereby the screw may be moved longitudinally while being rotated, a housing fixedly secured and positioned about and supporting the lead screw, a pair of nuts each having an arcuate threaded face for engagement with the lead screw and carried by the housing on opposite sides of the screw, fluid actuated means connected to the nuts for moving the nuts into and out of engagement with the screw, a shoulder adjacent the second end of the screw, a return plate rotatably supported from the second end of the lead screw and positioned against the shoulder on the side remote from the housing, a stop member supported on said second end of the lead screw forwardly of said return plate for securing said plate longitudinally thereon, spring return means connected between the housing and the return plate acting in a direction to pull the plate against the housing thereby returning the lead screw after threading when the nuts are retracted from the screw, means between the return plate and the housing preventing rotation of the plate, means on the second end of the lead screw for supporting a collapsible thread cutting means, and switch means controlling the fluid actuating said nuts and positioned in the path of said return plate and said stop member to be actuated by said stop member after the collapse of said thread cuttings means on the completion of the thread.