Abstract: In an electromagnetic spring-wound clutch, an input rotary member is concentrically and rotatably fitted on an output rotary member having an annular enlarged portion, with its axial boss disposed adjacent the above annular enlarged portion. A coil spring is wound around the axial boss and the annular enlarged portion for gripping engagement with at least the former, with its one end engaged by the output rotary member and its other end by a sleeve concentrically and rotatably supported on the input and output rotary members. An armature is disposed for axial tilting about its one edge supported by a stationary member. Responsive to extinction of electromagnetic force caused by deenergization of a magnetic coil, the armature is axially tilted by the force of a spring into engagement with the sleeve to hold same from rotating.

Abstract: An electromagnetic spring-wound clutch includes a first rotary member formed of a hub having an annular flange and a tubular portion integrally combined with the hub and adapted for direct coupling to a rotary shaft of an apparatus for use with the clutch. The tubular portion of the first rotary member is concentrically and rotatably fitted through a stationary annular field core which accommodates an electromagnetic coil and is arranged in facing relation with the annular flange of the hub. A non-magnetic annular member is rigidly fitted on the hub, and an armature is rotatably fitted on the hub and interposed between the annular flange and the annular member. A coil spring is wound around the annular member and a second rotary member rotatably fitted on the tubular portion of the first rotary member, for gripping engagement therewith.