Abstract: A control mechanism for the pull-down pawl of a projector, for the projection of films with different frame frequencies, comprises a pot-shaped worm gear and a control drum coaxial with and connected thereto for rotation therewith, movable in axial direction relative thereto and arrestable against a force of biasing means in one of a plurality of selected positions. The control drum is provided on its periphery with a plurality of different cam curves and a pin, movable in a direction normal to the axis of the control drum, engages with one a cam curve, brought in a selected position of the drum in alignment therewith, while the other end of the pin cooperates with a pull-down pawl to move an end of the latter into and out of perforations of the film. The worm gear meshes with a worm driven by a shaft carrying a cam engaged by a cam follower connected to the pull-down pawl to move the latter along a feed stroke when the end of the pull-down pawl is engaged in one of the film perforations.