Patent GB-565529-A (GB)
Title: Improvements in or relating to automatic firearms having a number of barrels
IPC: F41A19/18
Filed: 1941-09-22
Abstract: 565,529. Machine guns. JARNAKER, E. K. Sept. 22, 1941, No. 12227. [Class 92 (ii)] A machine gun having two, or more, fixed barrels has the firing mechanisms of the barrels so arranged that the hammer of each barrel is cocked by the recoil of the respective breechblock, or of a separate mass, and released for firing by the recoil of the other, or one of the other, breech-blocks or masses. The interconnecting mechanism for automatic fire may, however, be thrown out of action, in which case the single trigger operates the sears of the two, or more, firing mechanisms in turn, to fire single shots. A vertical longitudinal section through the left barrel of the double-barrelled gun, with hammer cocked, is shown in Fig. 1. Initially both breech-blocks 4 are simultaneously retracted by hand to load both barrels from separate magazines 11, the hammers 37 of both guns are simultaneously cocked, and are each held cocked by a separate automatic sear 42 and a common trigger-operated sear 53, the latter having two arms 52 (one only being seen in Fig. 1), one for each hammer. Each automatic sear 42 has a projection 46 adapted to be engaged both by the teeth of a star-wheel 48 and by a rod 50. The two star-wheels are mounted on a cross-spindle 49 and their teeth are relatively displaced by one half-pitch. On the spindle 48 is also mounted centrally a ratchet wheel 66 engaged by a pawl 65 pivoted to a front extension 64 of the trigger 62, which is pivoted at 61. When set for firing singleshots, the rods 50 are rendered inoperative, as described below. Pulling the trigger, disengages the forked sear 53 from both hammers 37, and lowers the pawl 65, which rotates the star-wheels 48 through an angle sufficient to cause the uppermost tooth of, say, the left-hand wheel to engage the projection 46 of the related automatic sear 42 and release that sear, the corresponding sear of the other barrel not being affected. The left-hand barrel is therefore fired. The recoil of the block 42 recocks the fallen hammer 37 and tensions its spring 41, and the sear 42 re-engages the bent 44 under the pressure of its spring 45. When the trigger is next pulled, the upper tooth of the right-hand star-wheel releases the right-hand sear 42 and the right barrel fires. This sets the left starwheel into position to fire the left barrel when the trigger is next pulled. Resistance to the recoil of the breech-blocks is provided by their respective main-springs 7 and also by a togglelink device 56, 58 arranged between a pivot 57 on the hammer and pivot 59 on the frame 10, whereby a leaf spring 60 is tensioned. The automatic firing mechanism comprises two sleeves 74, 77, Figs. 6 and 7, on a transverse shaft 70. Each sleeve has an upwardlyextending arm at one end (76, 79 respectively), projecting into the recoil paths of the two blocks 4, and a downwardly-extending arm at the other end (75, 78 respectively). The shaft 70 is carried in spring-pressed forwardly slidable bearing-blocks 71, which are supported at the rear by projections on a transversely-movable change-fire rod 67. For single-fire, the rod is in the position shown in plan in Fig. 7, and the blocks 71 are pressed to the rear by springs 72 against the minor projections 68 on the rod. In this position, the sleeve arms 76, 79 are not engaged by the recoiling breech-blocks. For automatic fire, the rod 67 is pressed in from right to left, and the projections 69 thrust the blocks 71 forwards, to bring the arms 76, 79 into block-engaging positions. When a barrel is then discharged by the initial trigger pull, the associated block 4 recoils and engages one of the two arms, thereby rocking its sleeve and causing the depending arm at the other end of the sleeve to thrust forwards a rod 50 and release the automatic sear 42 of the other barrel. The barrels are thus fired alternately so long as the pull on the trigger is maintained to hold the sears 52 out of action. A number of barrels may be arranged in groups, the groups being fired alternately by similar firing mechanisms, or the barrels in each group may be fired in rotation.