of strokes of striking mechanism 1 control member 42 is composed of a control piston 43 disposed in a chamber 47 and lying in its rest position not illustrated against an impact face 45 under the influence of a restoring spring 44 having a predetermined restoring force in the region of impact face 45 control piston 43 can be charged with operating pressure as illustrated by way of a control conduit 46 that is connected to pressure conduit 24 on its side facing restoring spring 44 control piston 43 is provided with a choke pin 43a which has a frustoconical end section 43b that more or less seals off the cross section of connecting channel 29 on its side opposite restoring spring 44 chamber 47 is connected by way of a relief channel 48 to return conduit 26 and can thus be relieved of pressure since the position of end section 43b relative to connection channel 29 determines the size of the exit cross section into return conduit 26 and thus the expulsion pressure that the striking piston must overcome during the return stroke a displacement of control piston 43 as a function of the operating pressure for striking mechanism 1 against the force of restoring spring.