Patent GB-348580-A (GB)
Title: Improvements in or relating to small arms
IPC: F41A35/02
Filed: 1930-02-13
Abstract: 348,580. Smallarms. COSMI, R., Macerata Feltria, Italy. Feb. 13, 1930, No. 4916. Convention date, Feb. 15, 1929. [Class 119.] In an automatic shot gun comprising a barrel 10, Fig. 1, carried by a guide casing 9 pivoted at 8 to the body 7 integral with the butt 1, the magazine 2, the cartridge lifter 3, the trigger gear 49, and the bolt-actuating means 5, 6 are arranged on the body 7, whereas the breech-bolt 12, the firing-pin 150, and the recoil mechanism 14 are arranged on the guide casing 9, so that these various devices are independent and accessible when the gun is open, Fig. 5, and are brought into co-operation when the gun is closed, Fig. 1. The barrel 10 has an extension 11, which slides in the guide casing 9, and a lug 15, which slides on the rod 14 against a recoil spring 21. The forward movement of the lug 15 is limited by a nut 14<1> screwed to the end of the rod 14. The rod 14 is screwed to the lump 20 by means of which the guide casing 9 is pivoted to eyes 19 on the body 7. A fore-end stock 16 embraces the eyes 19 by a hinge shoe 18, and is secured to the front end of the rod 14 by a catch 156, which is held in locking position by a spring 159 but can be pushed back by a knob 160 to release the fore-end stock for dismantling the gun. The breech-bolt 12 slides in the guide casing 9 against a plunger 5, which bears on a piston 26 movable in the stock against a coiled spring 6. In its forward position, the breechbolt is locked by a catch 123 which is pivoted at 122 on the breech-bolt and is urged by a spring 133 into a notch 114 in the barrel extension 11. When a shot is fired, the barrel and the breech-bolt recoil together and just before the end of the stroke the tail of the catch 123 is deflected bv a cam 174 and unlocks the breech-bolt from the barrel. The barrel with its extension 11 is then run out by the spring 21, while the breech-bolt after striking a leather pad 178 on the rear wall 172 of the guide casing is held back by a catch 105. During this opening of the breech, the spent cartridge is extracted by a hook 144, Fig. 15, pivoted to the breech-bolt 12 at 143 and is ejected through side openings in the barrel extension and the guide casing by the combined action of a pivoted ejector 145 on the breech-bolt and another pivoted ejector in the barrel extension. At the end of the run out the barrel pulls a spring catch 163, 170 forward, and this releases the front end 175 of the cartridge lifter 3, which is pivoted at 101 and to the rear end of which is pivoted the catch 105 which holds the breech-bolt back. When this release occurs, the catch 105 and the rear end of the cartridge lifter 3 are depressed by the action of the spring 6 on the breech-bolt, and the front end of the cartridge lifter in rising brings a fresh cartridge in line with the barrel, and at the same time a wing at the side of the lifter shuts the ejection opening. This action is followed by the release of the breech-bolt from the catch 105, the reclosing of the breech by the spring 6, and the relocking of the breechbolt by the catch 123. As the breech-bolt reaches its forward position it depresses the front end of the cartridge lifter down again into the body 7. The lifter is held in its raised and lowered positions by the action of a spring 59 on a double-faced cam 104 on the lifter. The cartridges are stored in the magazine 2 and are fed therefrom by a spring plunger 24 to a loading chamber 22 from whence they pass to the front end of the cartridge lifter 3, which is shaped like a shovel. When the shovel is lifted to present a fresh cartridge to the barrel, the next fresh cartridge is retained behind by a tooth 3<1> on the shovel. The second cartridge behind may be free to follow on or may be held back according to the setting given to a stop 61 in the bottom of the loading chamber. This stop is urged upward to operative position by the spring 59, but can be depressed by a lever 62 pivoted at 63 and controlled by a lever 64 pivoted at 65. If the lever 64 is set in its forward position it holds up the rear end 68 of the lever 62 and this holds the stop 61 down out of action. If the lever is set back, the finger 66 comes opposite a notch 67 in the lever 62 and this allows the stop 61 to rise to operative position. With the stop in this position, the cartridges held back thereby cannot be fired. When a cartridge is in the shovel end of the lifter 3, a blade 111 pivoted at 112, Fig. 7, in the body 7 is deflected against its spring 113 by the cartridge and does not interfere with the movement of the lifter; but, when the shovel is empty either because the last cartridge from the magazine has been fired or because the feed has been interrupted by the stop 61, the blade 111 springs over the shovel and holds it down, thereby holding the rear end of the lifter 3 with the catch 105 up in engagement with the breech-bolt, which is thereby held back in the breech-opening position. If now a locking lever 28 on the body 7 is turned to unlock the guide casing 9 from the body 7, and the gun is swung open about the pivot 8, cartridges may be loaded singly into the barrel and fired, or more cartridges may be inserted on the lifter or loaded into the magazine. The guide casing 9 is locked to the body 7 by a flange 35 of the lever 28 fitting in a notch in a lump 34 on the guide casing. The unlocking rotation of the lever 28 brings a notch 37 in the flange 35 in line with the lump 34 to release this lump, and at the same time brings another notch 38 in the flange 35 in line with a vertically sliding latch 39, 30, Figs. 7 and 10, which is moved up by a spring 31 to hold the lever 28 in the open position. If the breechbolt is in the retracted condition, the latch 30 moves slightly higher up and brings a tooth 40 into a notch 75 of the plunger 5, thereby locking this plunger in its rearward position. While the gun is open the breech-bolt, which is no longer subject to the action of the spring plunger 5, may be moved forward and backward by means of a handle 132 which then swings about its pivot 131 and protrudes below the guide casing. The parts arranged in the body 7 are mostly in the loading chamber 22 and can be easily dismantled by the removal of that chamber. When the gun is folded back, the lump 34 bears on a tooth 32 of the latch 30 and moves this latch down again, unlocking the plunger 5 and releasing the flange 35, whereupon a spring 43 rotates the lever 28 to the locking position. In the folded position of the gun, wings 181 on the rear end of the guide casing 9 engage recesses 182 in the body 7 to improve the safety of the gun. The firing is performed by a sliding firing-pin 150 in the breech-bolt when struck by a hammer 4, Fig. 8, pivoted at 76 in the body 7. The hammer is cocked by the recoil of the breechbolt. This moves the hammer back sufficiently for a shoulder 86 thereon to be engaged by a spring catch 96 pivoted to the front end 87 of a sear 88 which is pivoted at 89 and is kept down by a lever 92 overlaying an arm 91 on the sear. A tooth 94 on the lever 91 rides in a groove 72 in the plunger 5, and when this plunger reaches the end of its forward stroke in closing the breech, the inclined end 73 of the groove 72 deflects the lever 92, thereby releasing the arm 91 of the sear. The hammer 4, which is operated by a spring 77 through a piston 80 and a floating link 81, then makes a small upward swing, which rocks the sear to bring a shoulder 95 thereon into engagement with a shoulder 85 on the hammer while the catch 96 is deflected and slips off the shoulder 86. The gun may now be fired by a pull on the trigger 49 which rocks the sear 88 and thereby slips the shoulder 95 of the sear off the shoulder 85 of the hammer. With this arrangement, the shock of cocking is taken up by the shoulder 86 and catch 96, so that the sensitive shoulders 85, 95 controlled by the trigger are relieved from the wear due to such shock. The firing-spring 77 is confined in a tube 78 by a plug 79 secured by a bayonet-like joint. The trigger may be locked by a pin 51 operated by a lever 52 pivoted at 53 and connected by a link 54 to a knob on the top of the stock. Further safety is also provided by wedge-shaped lugs 135 on the breechbolt locking catch 123, which lugs wedge the firing- pin back when the catch unlocks the bolt, and retain this pin back until the catch relocks the breech-bolt in the closed position. The ejection opening at the side of the gun is closed by a shield 136, Fig. 15, which is slidably mounted on the breech-bolt and is held in an extended backward position by a spring 139. When the breech-bolt recoils the shield 136 is moved forward relatively thereto and compresses the spring 139 which takes its bearing on the extractor 142