Patent GB-347143-A (GB)
IPC: F41A3/26
Filed: 1929-10-14
Abstract: 347,143. Automatic firearms. SCHWARZLOSE, W., SCHWARZLOSE, M., and SCHWARZLOSE, C., 28, Speicherstrasse, St. Gallen, Switzerland. Oct. 14, 1929, No. 31131. Convention date, Oct. 12, 1928. Void [Published under Sect. 91 of the Acts]. [Class 119.] Relates to firearms in which the barrel is stationary and the breech-block is locked thereto when the shot is fired, but is automatically unlocked and recoiled. According to the invention, part of the energy of recoil is stored up and is used to unlock the breech-block and loosen the spent cartridge case when the next shot is fired. In the form shown in Fig. 1, when a trigger z is pulled, the breech-block v moves forward with the firing-pin a under the action of the recoil spring f bearing on a lug b<2> of the firing-pin. At the end of the stroke, the breech-block is rotated by the firing-pin through a lug and inclined slot connection n, c, and is thereby locked to lugs w on the barrel while the firing-pin fires the shot. The locking lugs w have abutment faces which are bevelled and curved. A weight o having a limited sliding engagement with the firing-pin by means of a cotter k moves forward with the breech-block and the firing-pin, but afterwards rebounds against a spring p. The energy of rebound pulls the firing-pin back to unlock the breech-block and loosen the spent cartridge case after the shot is fired, and the opening of the breech is completed by energy derived from the recoil of the whole gun or from the gas pressure in the barrel. This breech mechanism may also be operated by a handle g. In a modification, Fig. 3, the firing-pin a is drawn back by the lower end of a lever e when the upper end of this lever is struck by the weight o in its forward movement. In another modification, Fig. 5, the breech-block i is pivoted at x and is locked and unlocked at the front and back corners i<1>, h<2> by rocking movements imparted to it by lugs w<2>, v<2> on a slide v<1>. When the breech-block is unlocked after a shot is fired, it moves back with the slide v<1> to open the breech, but these parts are at once returned by the recoil spring f<1> to reload the gun and again close and lock the breech. The firing- pin and the weight o<2> are however held back by the trigger until this is pulled when a separate recoil spring drives these parts forward. At the end of this stroke a pawl on the weight o<2> engages a stop on the slide v<1> and rebounds against a spring as in the form shown in Fig. 1. This rebound pulls the slide v<1> back to unlock the breech-block, and the opening of the breech is then completed as before. In the form shown in Fig. 7, the breech-block v and the firing-pin u are arranged substantially in the same way as in Fig. 1, but the recoil spring f<2> fits axially into the firing-pin, and the weight g<1> surrounds the firing-pin and becomes connected to it only when the rebound spring p<2> is fully compressed, a pawl k<2> on the weight g<1> then snapping into a notch p<1> in the firing-pin. This ensures a quick unlocking of the breech when the shot is properly fired ; whereas in case of a missfire the pawl fails to act and the breech remains closed ; a separate safety against missfires is thus unnecessary. Before the recoil is completed, the pawl k<2> abuts against a shoulder d<3> in the breech casing and is by this deflected out of the notch p<1>. The breech casing is closed by a sliding cover d2 which is secured in place by the engagement of a lever m2 thereon over a lug c<1> on the breech casing. The spindle m<1> of this lever is shaped as shown, so that when the lever is rotated in a clockwise direction and unlocked from the lug c<1> the spindle ml lies in front of lugs u<2> on the firing-pin and the breech can therefore be opened by a backward movement of the sliding cover d<2>. When the breech mechanism is thus opened and is held open by the trigger z, the lever m<2> may be swung back whereupon the spindle m<1> will engage in front of the breech-block and lock it against forward movement. The guiding-pin t<1> of the recoil spring f<2> may then be disconnected from the end of the casing and connected to the firing-pin u, bayonet-like joints between these parts being provided for this purpose. The breech mechanism can then be removed from the casing. The weight g<1> is preferably cast in heavy metal, except the parts subject to wear, such as the notch for the trigger, which are made of steel. The heavy metal may be cast as a core inside a steel shell. The travel of the breech-block in the mechanism is shorter than usual; hence it cannot receive in front of it a cartridge direct from the usual magazine. The weight g<1> is therefore provided with a lug s<3> which moves the uppermost cartridge slightly forward in a position where it can be caught by the next stroke of the breech-block. This arrangement may be fitted to ordinary rifles. The breech mechanism is provided with a second trigger notch in front of the first one to hold the breechblock when this is drawn further back by hand to permit loading of the magazine. The extractor a2, a3, Fig. 13, slides in the breech casing, and is pivoted at its rear end to a lever c<2>, which abuts at ql on a shoulder in the breech casing and is thrust back by the firing-pin u, or by the slide v<1> of Fig. 5, to loosen the cartridge case to facilitate its extraction.