Patent GB-156221-A (GB)
Title: Improvements in small arms
IPC: F41A3/12
Filed: 1921-01-04
Abstract: 156,221. Rosebush, W. E. Aug. 80, 1916, [Convention date]. Breech actions, sliding breech-block; recoil, modifying; adapting for miniature ammunition; sights.- Relates to automatic pistols of the kind having a fixed barrel and a sliding breechblock which recoils against a spring but has no positive lock, and consists (1) in means for adapting the pistol for the use of long or short cartridges, (2) in providing interchangeable barrels of different calibres, (3) in providing means to compensate for the increased recoil of the breech-block when more powerful cartridges are used, and (4) in trigger mechanism adapted to fire single shots or continuously. In the construction shown, a sleeve 140 surrounding the breech-block can be locked by a catch 141, either to the breechblock so as to recoil therewith, or to the fixed barrel-frame 15. The sleeve is locked to the breechblock when more powerful cartridges are used, thereby increasing the inertia of the recoiling parts. The sleeve has two ejection openings 143, 144, Fig. 2, of different lengths, the short one 144 being in the operative position when the sleeve remains stationary and the long one when it recoils. The barrel 19, Fig. 3, has a reduced rear portion 18 fitting in a sleeve 16 on the barrel-frame which is secured to the main frame 10, Fig. 12, by a pivot bearing 13 and a spring catch 136, Fig. 3. A projection 22 on the frame enters a slot in the barrel and holds it against longitudinal movement. The firing mechanism comprises a firing- pin 50, hammer 70, sear 80, Fig. 7, and trigger 93. The sear is loosely mounted at the rear in a pivot hole 88, Fig. 12, so as to be capable of both sliding and rocking movements and is pressed rearwards by a spring 82. The trigger has a projecting nose 91, Fig. 8, adapted to engage a shoulder 89 at the front of the sear so that when the trigger is pulled the sear is moved forwards to release the hammer. Immediately the hammer is released the front end of the sear is moved downwards and released from the trigger. To adapt for continuous firing, the trigger is provided with a disc-like catch 110, Fig. 9, having a projection 114 which, when turned forwards, engages under an inclined ledge 115 on the sear and prevents the sear from becoming disengaged from the trigger, the hammer thus being free to strike the firing-pin every time the breech closes. The firing-pin 50 and extractor 165, Fig. 14, are mounted in borings in the breech-block which is provided with a rear cap 60, Fig. 16, adapted to slide vertically into position and to be locked by the projecting rear end of the firing-pin. To facilitate the assembling of the firing-pin and cap, the extractor has a rear projection 167 adapted to engage the end of the firing-pin to hold it forwards against the pressure of the rebound spring. The final movement in placing the cap in position rotates the extractor and moves the projection out of engagement with the firing-pin which is thereupon pressed back by its spring. The breech-block is held open, when the magazine is empty, by a lever 190, Fig. 11, having a projection 195 adapted to engage a notch in the breech-block and a projection 193 adapted to be engaged by the follower. The Specification as open to inspection under Sect. 91 (3) (a), comprises also a box magazine and a backsight. The box magazine has internal ribs 128, 129, Figs. 18 (Cancelled) and 30 (Cancelled) on each side to guide the cartridges, and is closed at the bottom by a slide 127. The follower 124 has finger-pieces 138 on each side sliding in slots 139. The backsight is carried by the breech-block cap, Fig. 16, and comprises a plate pierced with an aperture 202 and formed with a notch 203, the notch being separated from the aperture by a thin web. This subject-matter does not appear in the Specification as accepted.