GB126074A - Improvements in Automatic Guns. - Google Patents

Abstract

126,074. Davies, T. L., Hewitt, W. E., Nesfield, A. C., Sander, J., and Spittle, J. Nov. 30, 1916. Breech actions, sliding breech-block; sliding barrel and breech-block.-Consists of improvements in the lock mechanism, in the means for assembling the breechbolt and return spring, and in the hand-slide of automatic guns of either the recoiling barrel or gas-operated types. In Figs. 1 and 4, the invention is shown applied to a gun of the long barrel-recoil type. The essential feature of the lock mechanism is a pivoted quadrant 10 acting as the tiring-hammer and also as a detent to retain the breechblock in the rear position when the barrel goes forward to open the breech. The quadrant is pressed upwards by the barrelreturn spring 4, Figs. 1 and 4, acting through a sliding stirrup part 8 which forms the rear abutment of the spring and extends backwards past the magazine, where a cross pin 8<d> acts on the quadrant. The returnspring, guide-rod 5, and stirrup 8 can be withdrawn as a unit by first pushing forward the stirrup to disengage a hook part 8<c>. The quadrant is held by a sear 13 having a shaped opening 13a for the pivot pin 14, so that the sear can both turn and slide. The sear is pulled back against the influence of a spring 15 to release the quadrant by the direct action of the trigger 16 which is pivoted at 14 and has a projection 16<a> engaging a projection 13<c> on the sear. As the trigger is pulled, a rearward projection 13d thereon lifts the sear and disengages it from the projection 16<a> to allow it to re-engage the quadrant. The sear spring 15 abuts against the short arm of a bell-crank lever 17 pivoted at 22<b> on an arm of the safety mechanism and oscillated by a projection 16<b> on the trigger to increase the compression of the spring. At the end of the recoil, the quadrant 10 carrying with it the sear moves upwards and engages the bolt sleeve 12, as shown in Fig. 4, and the barrel runs out to open the breech. As the barrel approaches its forward position, a cam 18, Fig. 1, on the barrel-extension engages the top of the sear and depresses its together with the quadrant, thus releasing the bolt sleeve. When the magazine is empty, the sear is held back by a projection 21<b>, Fig. 4, on the lifter 21a engaging a forward projection 13* of the sear so that the sear cannot re-engage the quadrant which is therefore not depressed when the sear is actuated by the cam 18 on the barrel extension, so that the breech remains open. After the magazine is recharged, the quadrant is depressed by pushing the bar 17 forwards against a face 10<b> on the quadrant. This is effected by rocking the safety lever 22 at the end of which the bell-crank lever 17 is mounted. The safety lever has a projection adapted ta engage the trigger, and is turned by an external lever 23 through a stud and cam-slot connexion. In Figs. 22 and 26 is shown a modification wherein the sear can be automatically operated by the bolt sleeve for continuous firing. Mounted on a fixed pin 40 passing through a slot 13<e> in the sear is a bell-crank lever 42, adapted to be oscillated by a projection 12<b> on the bolt sleeve, and a slide 41 reciprocated by the cranked lever 42. The tail of the slide 41 can be depressed by external means to bring a projection 41<a>, Fig. 26, thereon into engagement with a shoulder 13<g> in an aperture in the sear which is then operated automatically. For single-shot firing, the tail of the slide is raised as shown in Fig. 22. When the invention is applied to a gas-operated gun, Fig. 34, the stirrup 8 is acted on by the return spring 4 of the piston which presses back tho bolt slide by means of a rearward extension formed at one side. The quadrant retains the breech slide in its rear position until the piston has returned to its forward position. The breechclosing spring 19, Figs. 18 and 20, is enclosed in a tube 53, Fig. 18, which at the rear is attached to the bolt sleeve 12 by a projection 53a, Fig. 20, passing through a slot 52*, Fig. 21, in the rear closing-cap 52 of the casing. The cap 52 is secured hy interrupted collars 'and if it is rotated to unlock it when the bolt sleeve is in its rear position, the projection 53a enters the cross part of the slot 52*, Fig. 21, and projections 52<e>, Fig. 1, enter pockets 12* in the bolt sleeve, so that the cap, bolt sleeve, closing- spring and its associated parts can be removed as a single unit. The hand slide 55, Figs. 18 and 31, is normally disconnected from the bolt sleeve but when it is retracted it is locked thereto bv a bolt 55<a> which enters a recess in tho tube 53. The bolt 55<a> is actuated by a resilient lever 55<c>, the forward end of which oooperates with the cam surfaces shown.