Actuating device with a securing means

摘要

An actuating device, in particular for a motor-vehicle friction clutch, having a drive which, at its drive shaft, produces a rotary movement for a driven shaft, and having a crank gear which converts the rotary movement of the driven shaft into an essentially translatory movement of an output member, is intended to be designed such that damage can be prevented even in the event of operating-voltage failure occurring for a brief period during the disengaging operation. For this purpose, provision is made to assign to the drive a securing means by means of which, upon exceeding a predeterminable moment difference between the drive shaft and the driven shaft, the torque supplied by the drive can be reduced to a predeterminable amount, before transmission to the driven shaft, by the formation of a counteracting moment of friction.