GB1013147A - Air gun or air pistol - Google Patents

Abstract

1,013,147. Air guns. MILLARD BROS. Ltd., and METCALF, A.G. March 1, 1963 [March 12, 1962], No. 9479/62. Heading F3C. In an air gun of the type in which a piston 3, Fig. 1, on release of a trigger, is driven forwardly within an air cylinder 2 by a spring 8 so as to compress the air and force it into the breech end of the barrel 1, sealing means 12, Fig. 1, or 20, Fig. 3, are located in the air cylinder 2 adjacent the breech end thereof, the sealing means having an axial passage for the flow of compressed air which, on release of the trigger, urges the sealing means into contact with a breech chamber or plate 13 or the breech end of the barrel to provide a seal between the breech part and the wall of the air cylinder 2. As shown in Fig. 1, a cylindrical chamber 9 at the forward end of the cylinder 2 slidably receives an auxiliary piston 10 having an axial bore 11 and an annular washer 12 of rubber, neoprene or metal. A breech plate 13 having a pellet receiving aperture 14 is slidably mounted between the breech end of the barrel and the cylinder 2, and is raised and lowered by operation of the cocking lever 4. On releasing the trigger the piston 10 is moved forwardly by the compressed-air and the washer 12 brought into sealing engagement with the breech plate 13. On re-cocking, the suction in the cylinder 2 moves the piston 10 rearwardly a short distance. As shown in Fig. 3, the sealing means comprises a flexible annular washer 20 located between annular lands 9a in the forward end of a cylindrical chamber 9. The washer 20 has an axial hole 11 having a bevelled edge. A breech plate 13 with a pellet receiving aperture slides horizontally in a downwardly open slot in the gun body, and has a downwardly projecting bolt 15a which engages in a curved cam slot 16, Fig. 4 (not shown) in a cam-plate 17. The cocking lever 4 operates the cam-plate 17 to move the breech plate outwardly to receive a pellet and then inwardly to align it with the breech. On firing, the flow of compressed air through the hole 11 distorts the washer 20 to form a seal between the wall of the cylinder 2 and the breech plate 13 and the seal is maintained by the compressed-air in the cylinder 2. The gun may be provided with a breech plate of the rotating or swinging type or with a rotating breech chamber.