Piston tool

Claim 1

A FASTENER DRIVING TOOL COMPRISING BARREL MEANS HAVING A BORE AND HAVING A BREECH END AND A FORWARD END, FASTENER GUIDE MEANS FOR RECEIVING A FASTENER TO BE DRIVEN AND SUPPORTED AT THE FORWARD END OF THE BARREL MEANS FOR LONGITUDINAL MOTION WITH RESPECT THERETO, PISTON MEANS SLIDABLY SUPPORTED IN THE BORE OF THE BARREL MEANS AND EXTENDING FORWARDLY INTO THE FASTENER GUIDE MEANS FOR ENGAGEMENT WITH A FASTENER RECEIVED IN THE GUIDE MEANS AND HELD AGAINST A WORKPIECE INTO WHICH IT IS TO BE DRIVEN, THE PISTON MEANS COMPRISING A MEMBER WHICH HAS A LENGTH GREAT ENOUGH TO EXTEND FROM THE BREECH END OF THE BARREL TO THE END OF A FASTENER IN THE GUIDE MEANS WHEN THE GUIDE MEANS IS MOVED REARWARDLY WITH RESPECT TO THE BARREL MEANS, CARTRIDGE RECEIVING MEANS AT THE BREECH END OF THE BARREL MEANS COMMUNICATING WITH THE BORE OF THE BARREL MEANS, BREECH BLOCK MEANS LONGITUDINALLY MOVABLE WITH RESPECT TO THE BARREL MEANS BETWEEN A POSITION LONGITUDINALLY SPACED FROM THE BREECH END OF THE BARREL MEANS AND A FORWARD POSITION ABUTTING THE BARREL END OF THE BARREL MEANS, FIRING PIN MEANS SLIDABLY SUPPORTED IN THE BREECH BLOCK MEANS AND URGED FORWARDLY THEREIN TOWARD A CARTRIDGE FIRING POSITION, SEAR MEANS NORMALLY INTERPOSED BETWEEN THE FIRING PIN MEANS AND THE BARREL MEANS TO PREVENT FORWARD MOTION OF THE FIRING PIN MEANS AS THE BREECH BLOCK MEANS IS MOVED TOWARD ITS FORWARD POSITION, AND TRIGGER MEANS ARRANGED TO DISPLACE THE SEAR MEAS FROM INTERPOSED RELATION WHEN THE BREECH BLOCK MEANS IS IN ITS FORWARD POSITION, THEREBY PERMITTING THE FIRING PIN TO MOVE FORWARDLY TO THE CARTRIDGE FIRING POSITION.