that is inside the automatic assembling machine nevertheless the installation personnel can be in dangerous areas if the cylinders 1 2 are pressurized in end positions by means of the safety apparatus that is switched into the primary pneumatic circuit in the described particular cases an inadvertent cylinder movement because of a control mistake is avoided simultaneously installation personnel are able to intentionally cause individual cylinder movements a further beneficial embodiment comes about if the control lines 8 1 9 1 and therefore also the control circuits 8 9 in the automatic assembling machine are laid using color distinguishing markings and are coupled with associated ports this allows a quick arranging of the functions in this manner the control circuit 8 can be characterized by having blue control lines 8 1 and the control circuit 9 can have red control lines 9 1 thus it is easy to recognize which ports must be exhausted and which closed it should be understood that other changes and modifications are also possible within the scope of the invention as can be understood by one of ordinary skill in the art from the specific embodiments described thus openable check valves of the type already present in the primary pneumatic circuit can be used in the structure of the additional control circuits 8 9 also it is possible to couple the ports 2 1 2 2 of the horizontal cylinder 2 with the control line 9 1 of the second control circuit 9 so that the hgl.