Devices for firing objects of the class of projectiles, plugs, pins and nails

Claim 1

IN A DEVICE FOR FIRING OBJECTS OF THE CLASS OF PROJECTILES, PLUGS, PINS AND NAILS WHICH ARE INTENDED TO BE PROPELLED UNDER THE ACTION OF AN EXPLOSIVE CHARGE OF THE TYPE IN WHICH THE IGNITION OF SAID CHARGE TAKES PLACE UNDER THE ACTION OF A PRESSURE RISE, SAID DEVICE COMPRISING A SUPPORTING STOCK, A GUN BARREL MOUNTED IN SAID STOCK, A COMPRESSED-AIR PUMP WHICH IS DISPOSED TO THE REAR OF SAID BARREL SO AS TO PROVIDE THEREWITH A SPACE FORMING A LOADING CHAMBER AND WHICH HAS A CYLINDER AND A PISTON MOVABLE WITHIN SAID CYLINDER, THERE BEING FORMED IN THAT END OF SAID PUMP CYLINDER WHICH IS DIRECTED TOWARDS SAID BARREL AT LEAST ONE DUCT PROVIDING A COMMUNICATION BETWEEN THE LOADING CHAMBER AND THE INTERIOR OF SAID CYLINDER, ELASTIC CONTROL MEANS FOR SAID PISTON WHICH ARE PLACED AGAINST THE REAR FACE OF THE PISTON AND TEND TO DRIVE SAID PISTON INTO THE CYLINDER SO AS TO COMPRESS THE AIR CONTAINED THEREIN AND TO DELIVER THE AIR UNDER PRESSURE INTO THE LOADING CHAMBER, AND COCKING MEANS FOR WITHDRAWING THE PISTON RELATIVELY TO THE CYLINDER-END AND AT THE SAME TIME FOR COMPRESSING THE ELASTIC CONTROL MEANS, THE FACT THAT THE WORKING FACE OF THE PISTON IS PROVIDED WITH A SUBSTANTIALLY FRUSTOCONICAL AXIAL RECESS, WHILST THE CYLINDER-END IS PROVIDED WITH A FRUSTO-CONICAL BOSS HAVING A SHAPE WHICH IS COMPLEMENTARY TO THAT OF SAID RECESS AND WITH MEANS FOR ADMITTING AIR THROUGH SAID BOSS SO AS TO ENABLE THE PUMP CYLINDER TO COMMUNICATE WITH THE LOADING CHAMBER.