Abstract: A spear for use with a spear gun includes a hollow shaft having a leading end and a trailing end opposite the leading end, a piston retained in the hollow shaft and configured to slide within the hollow shaft, and a check valve. The piston forms a seal with an inner surface of the hollow shaft and divides the hollow shaft into a pre-charge chamber toward the leading end and a firing charge chamber toward the trailing end. The check valve is in fluid communication with the pre-charge chamber and is configured to permit a pressurized gas pre-charge to enter the pre-charge chamber and restrict the gas pre-charge in the pre-charge chamber from exiting the pre-charge chamber.

Abstract: An apparatus for regulating and discharging gas includes a differential piston with first and second faces of unequal area. The differential piston reciprocates within a housing between a storage chamber and a discharge chamber, and includes an aperture extending between the first and second faces to allow the storage chamber to communicate with the discharge chamber. A spring positioned against the piston face with the smaller surface area biases the differential piston in the direction of the piston face with the larger surface area. The use of the apparatus allows a pneumatic device such as a pellet gun or a nail gun to rapidly recharge the firing chamber between firing cycles.

Abstract: An air gun includes an air pump with a pumping piston mounted to reciprocate within a pump cylinder, which is mounted on the barrel of the gun to pivot about an axis transverse to the longitudinal axis of the barrel so that as the pump cylinder is moved back and forth around the pivot, the cylinder and piston reciprocate relative to each other to pump air into a high pressure housing carried by the pump cylinder. A discharge conduit is also provided for releasably connecting the high pressure housing to the breach end of a gun barrel when the pump is moved toward the barrel. A firing valve in the discharge conduit releases air from the high pressure housing into the breach end of the barrel. Preferably, a floating differential piston disposed to reciprocate in a high pressure housing divides the housing into a storage chamber and a high pressure chamber.

Abstract: An air gun includes an air pump with a pumping piston mounted to reciprocate within a pump cylinder, which is mounted on the barrel of the gun to pivot about an axis transverse to the longitudinal axis of the barrel so that as the pump cylinder is moved back and forth around the pivot, the cylinder and piston reciprocate relative to each other to pump air into a high pressure housing carried by the pump cylinder. A discharge conduit is also provided for releasably connecting the high pressure housing to the breach end of a gun barrel when the pump is moved toward the barrel. A firing valve in the discharge conduit releases air from the high pressure housing into the breach end of the barrel. Preferably, a floating differential piston disposed to reciprocate in a high pressure housing divides the housing into a storage chamber and a high pressure chamber.

Abstract: Apparatus for storing and discharging gas includes a housing having an inlet and an outlet. A floating differential piston is mounted to reciprocate in the housing and divide the housing into a storage chamber adjacent the housing inlet and a discharge chamber adjacent the housing outlet. A check valve in the housing inlet admits gas to the storage chamber. A conduit extends through the piston from the storage chamber to the discharge chamber. A pressure relief valve in the conduit is set to maintain a higher pressure in the storage chamber than in the discharge chamber. A first sliding seal is disposed between the housing and an end of the piston adjacent the housing inlet. A second sliding seal is disposed between the housing and an end of the piston adjacent the housing outlet.

Abstract: Apparatus for storing and discharging gas includes a housing having an inlet and an outlet. A floating differential piston is mounted to reciprocate in the housing and divide the housing into a storage chamber adjacent the housing inlet and a discharge chamber adjacent the housing outlet. A check valve in the housing inlet admits gas to the storage chamber. A conduit extends through the piston from the storage chamber to the discharge chamber. A pressure relief valve in the conduit is set to maintain a higher pressure in the storage chamber than in the discharge chamber. A first sliding seal is disposed between the housing and an end of the piston adjacent the housing inlet. A second sliding seal is disposed between the housing and an end of the piston adjacent the housing outlet.

Abstract: An air gun includes an air pump with a pumping piston mounted to reciprocate within a pump cylinder, which is mounted on the barrel of the gun to pivot about an axis transverse to the longitudinal axis of the barrel so that as the pump cylinder is moved back and forth around the pivot, the cylinder and piston reciprocate relative to each other to pump air into a high pressure housing carried by the pump cylinder. A discharge conduit is also provided for releasably connecting the high pressure to the breach end of the barrel when the pump is moved toward the barrel. A firing valve in the discharge conduit releases air from the high pressure housing in to the breach end of the barrel.

Abstract: An air gun includes an air pump with a pumping piston mounted to reciprocate within a pump cylinder, which is mounted on the barrel of the gun to pivot about an axis transverse to the longitudinal axis of the barrel so that as the pump cylinder is moved back and forth around the pivot, the cylinder and piston reciprocate relative to each other to pump air into a high pressure housing carried by the pump cylinder. A discharge conduit is also provided for releasably connecting the high pressure housing to the breach end of a gun barrel when the pump is moved toward the barrel. A firing valve in the discharge conduit releases air from the high pressure housing into the breach end of the barrel. Preferably, a floating differential piston disposed to reciprocate in a high pressure housing divides the housing into a storage chamber and a high pressure chamber.