A piston rod is arranged in a body and provided with a helical element and an axial element. A guide element, which is arranged in the body and fixed relatively to the body, is coupled to the helical element to guide a helical movement of the piston rod and coupled to the axial element to guide an axial movement of the piston rod. The axial movement allows a priming of the device preceding the helical movement of the piston rod.
