Patent GB-191301923-A (GB)
Title: Improvements in Firing Mechanism for Guns.
Inventor: SMITH GEORGE LEONARD
IPC: F41A19/57
Filed: 1912-03-19
Granted: 1913-03-19
Abstract: 1923. Smith, G. L., and Asbury, D. F. March 19, 1912. Ordnance breech mechanism. - Relates to automatically-actuated magazine primer-locks, and consists in an arrangement wherein the firing-hammer is pivoted to the sliding-member, or " wedge," of the lock, and has a finger by which the primer is fed from the magazine into the vent. The magazine is carried by the wedge, which is temporarily arrested during its closing movement with the magazine opposite the vent; the hammer, which previously is held in a retracted position, then falls and pushes a primer into the vent. At the end of this movement, abutments on the hammer and the lockslide, or "receiver," move out of engagement, and the wedge is free to be moved forwards again into the firing-position. The firing is effected by pulling the hammer back against the pressure of its spring by a pivoted lever and connecting-rod, and then letting it fly forwards again. A projection on the breech-block engages the wedge and moves it towards the open position during the unlocking rotation of the plug, in the event of the normal cam-mechanism failing. The breech-block projection also prevents the return of the wedge to the firing- position until the breech is practically locked. The operating-cam is formed on the shaft of the radially-disposed breech-actuating crank, which latter is of the kind described in Specification 6739/12. The magazine and operating- parts are constructed so that they may be inverted for use with either right or left handed breech-mechanisms. Automatlc means are provided for disconnecting the cam-stud from the cam in the event of the lock jamming. Fig 1 is a rear elevation of the mechanism, and Fig. 4 is a sectional plan of part of the lock mechanism. The hammer 20 of the lock is pivoted at 20<d> to the " wedge " 18, which wedge is reciprocated, during the opening and closing of the gun-breech, in a slide, or " receiver," 16 mounted upon the rear end of the obturator stem 14b. The wedge carries the primer magazine 19, and has a cam-groove 18a, for operating the extractors 17, and an incline 18<c> for pushing-home the freshly-inserted primer. The hammer 20 has a firing-pin 21 for electric and percussion firing, and has also a " prong " 20<e> which enters the magazine when the hammer first falls and pushes the lowermost primer from the magazine into the vent 14<d>. The mechanism actuating the lock comprises a cam-groove in a collar 11 on the radially-arranged shaft 8 of the breech-operating mechanism. The camgroove has two operative portions with a dwell between them, the dwell corresponding with the position of the wedge 18 in which the magazine 19 is alined with the vent 14<a>. In closing the breech, the hammer 20 is held in the raised position, shown in dotted lines in Fig. 4, by a pivoted latch which forms the bottom of the magazine 19, until a cam-groove in the receiver 16 rocks the latch into its inoperative position. The hammer, thus released, while the wedge remains stationary, is rocked about its pivot 20<d> by a spring 29, acting through a connecting-rod 24, and pushes a primer 22 into the vent. Stops on the hammer, at the same time, move clear of abutments on the receiver, so that the wedge and depressed hammer can now be moved to the firing-position, shown in full lines in Fig. 4, by the second operative portion of the cam 11. Percussion firing is effected by retracting the hammer and compressing the spring 29 by means of a firing-lever (not shown) and then letting go the lever. A stop 20b on the hammer coacts with a recess 16<j> in the rear vertical edge of the receiver 16 to prevent the firing-pin 21 striking the primer until the wedge 18 is in the correct position. During the opening movement of the wedge, the rear inclined edge of the recess 16<j> slightly retracts the striker, and later, a toe 20<c> on the hammer strikes a stop 16<l> on the receiver 16, and rocks the hammer into the fully-raised position. A projecting-rib 10<e> on the breech-block 2 acts, during the unlocking rotation of the breechblock, upon an inclined projection on the end 18<f> of the wedge 18, if the normal lock-retracting mechanism fails to act, and moves the wedge aside. The rib 10<e> also prevents the return of the wedge to the firing position until the breech-block has nearly completed its locking-rotation. The lock mechanism may be operated by hand, from the side of the gun, by a handle 31<b>, the rocking of which on a vertical pivot disconnects the cam-gear. The Specification mentions, but does not claim, an hydraulically-operated plunger for effecting the cocking and release of the hammer, for percussion firing.