Coupling for winding and unwinding mandrels or the like

摘要

A coupling between a motor-driven shaft and a mandrel for winding or unwinding reels has a recess provided in the end portion of the shaft and serving to receive the end portion of the mandrel. The end portion of the shaft has a wheel which is pivotable between an inoperative position to permit insertion of the end portion of the mandrel into the recess and an operative position in which the end portion of the mandrel is confined in the recess. The end portion of the mandrel has a non-circular peripheral surface which is surrounded by the complementary surface of the end portion of the shaft when the end portion of the mandrel is properly inserted into the recess and the wheel is held in the operative position. In order to ensure that the shaft can drive the mandrel, even if the wheel is held in the inoperative position and/or during starting of the mandrel, the bottom face of the end portion of the shaft in the recess or the end face of the end portion of the mandrel has a pivotable tongue or a reciprocable pin which is biased into a complementary groove or hole in the end face of the end portion of the mandrel or in the bottom face in the recess as soon as the mandrel is properly inserted into that part of the recess which is provided in the non-pivotable section of the end portion of the shaft.