Self-locking device for transmitting torque to bobbin cores

摘要

A self-locking chuck which can clamp the hollow core of a bobbin to a rotor has two nuts which mate with externally threaded sections of the rotor and have threads inclined in opposite directions or threads of different pitch so that they move axially toward or away from each other in response to joint rotation relative to the rotor or vice versa. The nuts are surrounded by two or more axially parallel torque transmitting segments whose external surfaces are movable into torque-transmitting engagement with the internal surface of a core in response to joint rotation of the nuts relative to the rotor. To this end, the inner sides of the segments are provided with a first set of cam faces and the outer sides of the nuts are provided with a second set of cam faces which cooperate with the cam faces of the segments to move the segments radially outwardly in response to joint rotation of the nuts relative to the rotor. Such rotation can be brought about by the internal surface of the core through the medium of the segments.