Patent GB-1381584-A (GB)
Title: Air gun
IPC: F41B11/26
Filed: 1973-05-30
Abstract: 1381584 Air gun VICTOR COMPTOMETER CORP 30 May 1973 [16 June 1972] 25726/73 Heading F3C  A gun has a barrel 118, Fig. 11, through which a projectile 311 or 312 is to be fired by compressed air and comprises a tubular member 80 mounted in the gun, a cylindrical block 82, having an outside diameter corresponding to the inside diameter of the tubular member 80, being mounted intermediate the ends of the tubular member 80 and dividing the tubular member 80 into a compression chamber 145 and an air storage chamber 216, an air passage 236 in the cylindrical block 82 connecting the compression chamber 145 to the storage chamber 216, a piston assembly 140, Figs. 1 and 8, slidably mounted in the compression chamber 145, Fig. 11, for reciprocable movement between a retracted position spaced from the cylindrical block 82 and an extended position located closely adjacent said cylindrical block 82, whereby upon reciprocation of the piston assembly 140, compressed air is forced from the compression chamber 145 through the pasasge 236 to the air storage chamber 216, a valve block 88, having a cylindrical portion with an outside diameter corresponding to the inside diameter of the tubular member 80, and being mounted in the air storage chamber 216 in spaced relationship to the cylindrical block 82, and a resilient compressible cylindrical sealing member 218, having an outside diameter corresponding to the inside diameter of the tubular member 80 and an axial length corresponding to the axial spacing of the cylindrical portion of the valve block 88 from the cylindrical block 82, and being mounted between the cylndrical block 82 and the valve block 88 in sealing engagement with the tubular member 80. The cylindrical block 82 has a valve seat 238 formed therein which is engageable by a head portion 242 of the sealing member 218. The latter having ribs 244, 246 which connect the head portion 242 to a cylindrical portion 220 of the sealing member 218. The valve block 88 has a release valve 268 mounted thereon for controlling the flow of air from the storage chamber 216 to an inlet passage 264 formed in the barrel 118. The release valve 268 comprises a piston 282 having a rod 290, a spring 286 which urges the piston 282 towards a passage 262 which connects to the inlet passage 264, seals 292, 294 and 296 which slidably receive the rod 290 therein, and a plug 270 in which the seals 292, 294 and 296 are mounted and which, having screw threads, is secured to the valve block 88. In operation, air is compressed by a lever 144, Fig. 1, which is pivotally mounted to housing 60 by a pin 208, and which, when actuated, pulls drag link 190 to move pivot pin 176 longitudinally along a track in the housing 60 on rollers 172, 174, Fig. 7. Piston rod 150, Fig. 1, and piston 140 are pulled to a retracted position (not shown) providing maximum volume in the chamber 145, Fig. 11. The aircompression stroke is effected by moving the piston 140, Fig. 1, towards the block member 82. The piston 140 engages the block member 82 without jamming due to the lost-motion connection between the piston and the piston rod produced by the pin 154 and slots 156, and due to an elastomeric annulus 164. Pressurized-air is forced through the passage 236, Fig. 11, and moves the head portion 242 of the sealing member 218 from its seat 238 so that the pressurized-air can be stored in the storage chamber 216. Several compression strokes may be utilized to build a desired level of pressure in the chamber 216. In order to load the gun and cock the firing mechanism, handle 384, Fig. 2, on a bolt 244, Fig. 1, is pulled rearwardly, the handle 384 first pivoting inwardly to clear an abutment surface 398, Fig. 10, relative to an edge 400 of a receiver slot 34 and then moving rearwardly along surface 105 to the retracted position. During rearward movement, rear wall 362 of the body portion of the gun will engage cam surface 340, Fig. 1, of a control lever 300, if the gun is uncocked, and force down the rear portion of the control lever 300 by pivotal movement about pin 310. Downward pivotal movement of the rear end of the control lever exerts a pivotal force on the trigger 313 through compression spring 326 and maintains cam surface 318 of latch finger 316 in engagement with side surface 334 of latch lug 324. When the latter clears the cam surface, the compression spring acts to pivot an end of the latch finger over the latch lug with surfaces 320, 322 and 332, 334 engaging to hold the control lever in a cooked position until released by pulling the trigger rearwardly about pin 314 to move latch finger surface 320 off lug surface 322, the spring 326 pivoting the control lever 300 from the cocked position to a valve-releasing firing position. In the retracted cocking and loading position, the cylindrical bolt portion 352 is moved rearwardly to clear the rear end of the barrel, a loading slot 36, Fig. 2, and the pellet opening so that a pellet may be loaded into the barrel. The bolt 344, Fig. 1, is then moved forwardly to push the pellet into firing position with a lip 406, Fig. 11, of the bolt entering a tapered part 412 of the barrel bore 120 so as to effect sealing of the latter. In the forward firing position the bolt handle 384, Fig. 10, is pivotally outwardly biased by spring finger to seat the handle latch surface 398 against the receiver slot abutment surface 400 and prevent rearward movement of the bolt. Pivotal movement of the control lever 300, Fig. 1, to the firing position pulls the release valve 268 open against the bias of the spring 286, Fig. 11, due to engagement between cam surface 304, Fig. 9, on the control lever actuating finger portion 306 of the control lever 300 and the surface 308 on an abutment washer 302 attached to valve stem 290. When valve head 274, Fig. 11, clears valve seat 278, pressurized-air in the storage chamber 216 enters outlet passage 262 and the valve remains open against the bias of the spring 286 until the pressure of the air in the chamber 216 is reduced, the pellet having been fired by passage of air into the barrel bore via inlet passage 264.