Device for transmitting a mechanical force for driving a pressing device for press fittings - having a storage container for hydraulic fluid, - having a pump cylinder with a pump piston, - having a working cylinder with a working piston, - having a first line for connecting the storage container to the pump cylinder, - having a second line for connecting the pump cylinder to the working cylinder, and - having a third line for connecting the working cylinder to the storage container, - wherein means for preventing a return flow of hydraulic fluid from the pump cylinder into the storage container are provided in the first line, - wherein means for preventing a return flow of hydraulic fluid from the working cylinder into the pump cylinder are provided in the second line, - wherein switching means for opening and closing the third line are provided, - wherein the piston displacement of the working cylinder is configured to be greater than the piston displacement (Vp) of the pump cylinder, - wherein the means for preventing a return flow in the first line and in the second line are designed as a non-return valve (20, 22), and - wherein the switching means of the third line are designed as a switching valve characterized in that - a fourth line with a pressure limiting valve branches off in the direction of flow after the non-return valve arranged in the second line, wherein a control line connects the pressure limiting valve to the switching valve, and/or - wherein the switching valve has a mechanical plunger, wherein the working piston is arranged in such a way that the working piston, during a return stroke, actuates the plunger and closes the switching valve. - having a storage container for hydraulic fluid, - having a pump cylinder with a pump piston, - having a working cylinder with a working piston, - having a first line for connecting the storage container to the pump cylinder, - having a second line for connecting the pump cylinder to the working cylinder, and - having a third line for connecting the working cylinder to the storage container, - wherein means for preventing a return flow of hydraulic fluid from the pump cylinder into the storage container are provided in the first line, - wherein means for preventing a return flow of hydraulic fluid from the working cylinder into the pump cylinder are provided in the second line, - wherein switching means for opening and closing the third line are provided, - wherein the piston displacement of the working cylinder is configured to be greater than the piston displacement (Vp) of the pump cylinder, - wherein the means for preventing a return flow in the first line and in the second line are designed as a non-return valve (20, 22), and - wherein the switching means of the third line are designed as a switching valve - a fourth line with a pressure limiting valve branches off in the direction of flow after the non-return valve arranged in the second line, wherein a control line connects the pressure limiting valve to the switching valve, and/or - wherein the switching valve has a mechanical plunger, wherein the working piston is arranged in such a way that the working piston, during a return stroke, actuates the plunger and closes the switching valve.