A rotational coupling includes input and output hubs disposed about a rotational axis and an attachment ring disposed about the axis on one side of the input hub opposite the output hub. A flexible, multi-coil body such as a cable is disposed radially outwardly of the input and output hubs and couples the hubs together for rotation upon rotation of the input hub in one rotational direction. The body has ends coupled to the output hub and attachment ring. A torque limiter includes a torque transmission plate configured to rotate with the input hub and an armature plate fixed against rotation. The torque transmission plate and armature plate are configured to move axially together along the axis of rotation. An electromagnet disposed on one side of the torque limiter opposite the input hub attracts the plates in a second axial direction away from the attachment ring when energized.

A clutched driven device (10) having a clutch assembly (16) with a first rotary clutch portion (50), a second rotary clutch portion (52), a bearing (54), a wrap spring (56) and an actuator (60). The first rotary clutch portion has an interior clutch surface (76). The first and second rotary clutch portions are rotatably disposed about a rotary axis (70) of the clutched driven device. The bearing is received between the first and second rotary clutch portions and supports the first rotary clutch portion for rotation on the second rotary clutch portion. The wrap spring is disposed radially inwardly of the bearing and has a plurality of helical coils (114) that are received against the interior clutch surface. The actuator is configured to selectively initiate coiling of the wrap spring to cause the helical coils of the wrap spring to disengage the interior clutch surface to a predetermined extent.

A clutched driven device (10) having a clutch assembly (16) with a first rotary clutch portion (50), a second rotary clutch portion (52), a bearing (54), a wrap spring (56) and an actuator (60). The first rotary clutch portion has an interior clutch surface (76). The first and second rotary clutch portions are rotatably disposed about a rotary axis (70) of the clutched driven device. The bearing is received between the first and second rotary clutch portions and supports the first rotary clutch portion for rotation on the second rotary clutch portion. The wrap spring is disposed radially inwardly of the bearing and has a plurality of helical coils (114) that are received against the interior clutch surface. The actuator is configured to selectively initiate coiling of the wrap spring to cause the helical coils of the wrap spring to disengage the interior clutch surface to a predetermined extent.

A rotational coupling includes input and output hubs disposed about a rotational axis and an attachment ring disposed about the axis on one side of the input hub opposite the output hub. A flexible, multi-coil body such as a cable is disposed radially outwardly of the input and output hubs and couples the hubs together for rotation upon rotation of the input hub in one rotational direction. The body has ends coupled to the output hub and attachment ring. A torque limiter includes a torque transmission plate configured to rotate with the input hub and an armature plate fixed against rotation. The torque transmission plate and armature plate are configured to move axially together along the axis of rotation. An electromagnet disposed on one side of the torque limiter opposite the input hub attracts the plates in a second axial direction away from the attachment ring when energized.

A compact clutch which comprises a driven shaft on which the following are mounted: a gear wheel; a driving bush; a driven bush; a coil spring; a first collar with cam surfaces; and a second collar with cam surfaces. The clutch is characterized in that the gear wheel and the bushes are constrained to the driven shaft in the axial direction by means of two stop rings; in that the driven bush is constrained to the driven shaft in the circumferential direction by means of at least one tongue; and in that the tongue ensures engagement between the driven bush and the driven shaft in the circumferential direction, while in the axial direction the driven bush may slide with respect to the driven shaft.