it is positioned between the upper disengagement cam 24 and the engagement cam 26 in such a manner that when the piston 3 is disengaged by the operating lever 74 of the disengagement apparatus 7 hitting against the lower disengagement cam 25 the pump lever 55 of the injection apparatus 5 was not passed completely and therefore no fuel feed by means of the injection apparatus 5 takes place during the subsequent drop of the piston 3 the piston 3 therefore impacts the striker 4 only once thereby causing the post to be driven to experience only one impact by means of repeating this method of procedure u201c gentle u201d controlled driving of the post particularly into soft subsoil is possible after the lower disengagement cam 25 has been moved in the piston 3 can then be moved further upward by way of the disengagement apparatus 7 until the operating lever 74 makes contact with the upper disengagement cam 24 in this connection the piston 3 has moved completely past the pump lever 55 and for this reason the pump lever 55 projects into the cylinder space 2 because of its bias when the piston subsequently drops the pump lever 55 is thereby activated and therefore fuel injection onto the fuel bowl 46 of the striker 4 takes place the diesel hammer pile driver 1 is thereby started furthermore a rotatably mounted circular disk 77 is disposed on the disengagement apparatus 7 above the driver 73 which disk is connected with two detents 76 that project in opposite directions in.