Abstract: Discrete disturbance features are included in a process member drive train coupling mechanism to prevent the mechanism from remaining in a disengaged position. The mechanism may include a rotatable drive receiver operative to rotate an electrophotographic imaging process member and a coupler including a driver. The driver and drive receiver may include respective mating drive features to transmit rotary drive forces to the process member. The coupling mechanism includes one or more disturbance features located at discrete radial positions relative to a rotation axis of the coupler at an interface between the driver and the drive receiver. As the coupler rotates, the disturbance feature disrupts the position of the coupler to align the driver and drive receiver and move the coupler towards an engaged position in which the first and second drive features are engaged.

Abstract: A carriage return device utilizing a spring clutch and shock unloader spring is disclosed in conjunction with a cord tension sensing mechanism for detecting the cord tension increases when the paper carriage of a typewriter ceases to move and the carriage return drive mechanism continues to operate. It is desirable to disengage the drive mechanism at that point rather than to cause frictional wear or overloading of the motor pending a predetermined amount of driving time prior to disengagement. Upon the cord tension reaching a preset value, the clutch pawl will disengage the drive clutch and prevent further wear of the clutching arrangement. To prevent premature disengagement of the clutch, a shock unloading pretensioned spring is incorporated in the drive unit to absorb the initial shocks of clutch engagement and the forces experienced during acceleration of the paper carriage.