Fastener driving apparatus

Claim 1

A FASTENER DRIVING TOOL COMPRISING A HOUSING HAVING A CYLINDER, FASTENER DRIVING MEANS INCLUDING A PISTON MOVABLY MOUNTED WITHIN THE CYLINDER, SAID PISTON BEING NORMALLY DISPOSED AT ONE END OF THE CYLINDER AND BEING MOVABLE DURING A POWER STROKE TO THE OPPOSITE END OF THE CYLINDER, CYLINDER MEANS CONCENTRIC WITH THE CYLINDER AND DISPOSED AT SAID OPPOSITE END OF THE CYLINDER, SAID CYLINDER MEANS HAVING PORTIONS OF DIFFERENT DIAMETERS SLIDABLY MEANS OF CORRESPONDING DIFFERENT DIAMETERS SLIDABLY MOUNTED IN THE CYLINDER MEANS, MEANS FOR SUPPLYING A PRESSURIZED FLUID TO THE CYLINDER MEANS BETWEEN SAID PORTIONS OF DIFFERENT DIAMETER TO BIAS THE PISTON MEANS TOWARD THE DRIVE PISTON, AND MEANS FOR LIMITING MOVEMENT OF THE PISTON MEANS TOWARD THE DRIVE PISTON SO THAT THE PISTON MEANS IS SPACED FROM BUT DISPOSED IN THE PATH OF MOVEMENT OF THE DRIVE PISTON DURING A POWER STROKE, SAID PISTON MEANS BEING ENGAGED AND MOVED AGAINST THE BIAS OF THE PRESSURIZED FLUID BY THE DRIVE PISTON TO CUSHION THE TERMINATION OF THE POWER STROKE OF THE DRIVE PISTON.