photographic camera 10 it also sets the shutter of the camera any change in the load moment applied to the coupling projections 28 is transmitted by way of the driven shaft 25 and the spur gear 24 to the pinion 22 because of the helical gear teething 23 of the pinion 22 there results a reactive force acting upon the pinion 22 and depending on the load moment applied the variable force is axially directed as a parameter onto the flanks of the helical teeth 23 corresponding to the angle of inclination of the helical teeth as the result the shaft 20 and thus the driven disk 21 are axially displaced whereby the contact pressure between the driven disk 21 and the o ring 18 is changed with the elastic deformation of the latter and correspondingly a higher or lesser frictional contact pressure is obtained depending on the conditions of the load it is obvious that in place of the frictionally effective o ring the bottom side of the driven disk 21 may be made elastically deformable and be provided with an equally frictionally effective covering while the rotating body 16 may consist of a hard material depending on the distance maintained by the rotating body 16 in relation to the axis of the shaft 20 the reduction ratio of the drive.