Pneumatic fastener driving machine

Claim 1

IN A PNEUMATIC DRIVING MACHINE, A FRAME STRUCTURE INCLUDING A HEAD PORTION, SAID HEAD PORTION HAVING A TOP OPENING WITH A REMOVABLY SECURED CLOSURE CAP MEMBER CLOSING THE SAME, SAID HEAD PORTION HAVING THEREIN A PRESSURE FLUID RESERVOIR OF LARGE VOLUME WITHIN WHICH A CYLINDER IS PROVIDED WITH AN END OPENING ARRANGED FOR EXPOSURE WITHIN THE RESERVOIR SUBSTANTIALLY SPACED BELOW SAID CLOSURE CAP, A DRIVING MEMBER ACTUATING PISTON RECIPROCABLY OPERABLE IN SAID CYLINDER AND CARRYING A DRIVING MEMBER DIRECTED TOWARD THE OPPOSITE END OF THE CYLINDER FROM SAID END OPENING, MEANS NORMALLY URGING THE PISTON TOWARD SAID END OPENING, SAID END OPENING BEING UNOBSTRUCTED SO THAT THE PISTON AND DRIVING MEMBER CAN BE ASSEMBLED OR REMOVED THERETHROUGH AND THROUGH THE OPEN END OF SAID HEAD PORTION WHEN SAID CLOSURE CAP IS REMOVED, SAID CLOSURE CAP HAVING PROJECTING THEREFROM AND INTO THE UPPER PORTION OF SAID CYLINDER STOP MEANS ENGAGEABLE BY THE PISTON TO NORMALLY HOLD THE TOP OF THE PISTON BELOW THE END OPENING, AND MEANS NORMALLY CLOSING SAID CYLINDER END OPENING BUT SHIFTABLE TOWARD OPEN POSITION FOR OPENING THE CYLINDER TO FULL FLUID PRESSURE FROM WITHIN THE RESERVOIR FOR DRIVING THE PISTON AND SAID MEMBER IN A DRIVING STROKE THEREOF, SAID STOP MEANS INCLUDING AN EXHAUST PASSAGE SYSTEM FROM SAID CYLINDER ABOVE SAID PISTON.