In the production of film, it is fed between two rollers, one of which is driven to transport the film. The second roller is pressed on by a pneumatic cylinder. In order to prevent the cylinder from moving out of position in the event of a fault, e.g. if several films overlap, and therefore a loss of feed, the cylinder is hydraulically locked so that it always remains in the position once set. To rectify the fault, this lock can be released by a pneumatic signal.