Pneumatic gun for rapid repetitive firing

Abstract

A pneumatic gun or air gun having a fast-acting sliding valve reciprocable between two axial positions to close or open intake and exhaust ports in a charge chamber in a housing. The sliding valve comprises a piston internal to the housing and may include a piston in a cylinder within and extending beyond the housing. The sliding valve has a sealing flange which forms a lip seal with an annular mating surface of the housing to close an exhaust port. Air accelerating from the gun may be radial from an equatorial exhaust port or may be axial from an end of the charge chamber. The charge chamber is provided with an intake port in selective communication with a source of pressurized gas, thereby to facilitate rapid charging rates. The intake port is closed when the exhaust port is opened by the sliding action of the valve member, and is opened when the lip seal is formed to close the exhaust port. The intake passages to the charge chamber are essentially unrestrictive of the flow of pressurized gas, thereby to facilitate rapid charging rates. The valve is fitted with an annular cocking flange which is disposed in a cocking chamber in the housing and is supplied with pressurized gas on one side to exert a continuous closing force to form and maintain the lip seal. Pressurized gas is provided selectively to the opposite side of the cocking flange to generate an opening force on the valve which is larger than the closing force, thereby breaking the lip seal and permitting gas to discharge suddenly from the charge chamber. In the axial end discharge embodiment, the acoustic output of the gun includes not only the explosive acceleration of gas from the exhaust port, but also the abrupt volume acceleration off the face of the piston.