Drive unit

A drive unit comprising:

• a housing defining a rotational axis;
• a motor supported by the housing;
• a drive shaft supported by the housing for rotation about the rotational axis;
• gearing operatively connecting the motor and the drive shaft;
• an actuator supported by the housing for rotation about the rotational axis responsive to rotation of the drive shaft;
• a friction ring slidably and non-rotatably mounted to the drive shaft and including a first frictional surface rotatable with the drive shaft, the actuator including a second frictional surface disposed about the first frictional surface, the first and second frictional surfaces being mating conical frustrum surfaces, the first frictional surface driving the second frictional surface via friction upon rotation of the drive shaft;
• a detent non-rotatably secured to a distal end of the drive shaft;
• a compression disk non-rotatably secured to the drive shaft;
• and
• a compression spring disposed between the detent and the compression disk for urging the compression disk against the actuator, thereby urging the first and second frictional surfaces together.