Abstract: A rotational coupling device is provided having an improved actuator for compressing friction discs coupled to an input ring and an output hub disposed about a rotational axis. The actuator includes a pole structure and a field shell housing a conductor, each with aligned, axially extending, radially spaced inner and outer poles. An armature is coupled for rotation with the input ring, but axially movable relative thereto and axially aligned with an end wall of the pole structure extending between the inner and outer actuator poles. First and second axially spaced actuator discs are disposed radially between the pole structure and the output hub with the first actuator disc rotatably coupled to the pole structure. The discs define cam surfaces along which a plurality of balls move to expand and contract the actuator discs upon relative rotation of the actuator discs.

Abstract: A rotational coupling device is provided having an improved actuator for compressing friction discs coupled to an input ring and an output hub disposed about a rotational axis. The actuator includes a pole structure and a field shell housing a conductor, each with aligned, axially extending, radially spaced inner and outer poles. An armature is coupled for rotation with the input ring, but axially movable relative thereto and axially aligned with an end wall of the pole structure extending between the inner and outer actuator poles. First and second axially spaced actuator discs are disposed radially between the pole structure and the output hub with the first actuator disc rotatably coupled to the pole structure. The discs define cam surfaces along which a plurality of balls move to expand and contract the actuator discs upon relative rotation of the actuator discs.

Abstract: The armature of an electromagnetic clutch is connected to an axially fixed elastomeric ring by leaf springs which urge the armature away from the electromagnet. Rivets connect the springs to the armature and are formed with pin-like extensions which are telescoped snugly but slidably into holes in the ring. When the magnet is initially excited, the ring frictionally retards movement of the pin-like extensions to cause the armature to softly and quietly engage the magnet rather than slapping sharply against the magnet.