The Works Of Messrs. Schneider And Co.

SINGLE-MOTION BREECH-MECHANISM. 203 from left to right; during the first period the catch leaves the gun, and the lever, on getting away from the breech-block support, works the endless screw, which produces the release of the block. In the second period, the whole of the mechanism, drawn by the hand-lever pivots round the vertical hinge, until the breech of the gun is completely freed, the latch fixing the block on its axis ; when the swinging round is complété, the mechanism bears on the heel of the extractor, which effects the éjection of the cai’tridge-case. to the centre line of the gun. It is united to the support by a screwed joint of the type described for the pre- ceding breecli-piece, The breech-block support consists of a circular disc, which pivots round a vertical hinge on the right hand of the gun; it carries all the mechanism. In its central plane is the socket for the conical pinion fitted to the hand-lever. The lower part of the breech- block is fitted with a pinion of the same shape, the two pinions, by acting on the hand-lever, screwing or unscrewing the breech-block in its seat. Fig. 675. Fig. 676. Single-Motion Breech-Mechanism for Quick-Firing Guns, with Conical Block. To close the breech, the action is repeated inversely. When the breech is closed, it is sufficient to pull the firing- line to fire the gun ; the firing device cannot act until the breech is completely closed. Conical Breech - Block, with Repeat Firing Action (Figs. 672 to 674).—This type is very similar to the 1 preceding one, thougli the breech-block is conical, and the working mechanism consists of conical pinion gearing. Ihe block has two threaded parts and two inter- ruptions ; swinging to the side takes place immediately after unscrewing, the block not being shifted with regard The hand-lever is provided with a spiral spring, the object of which is to ensure the locking of the system when the breech is completely closed. The extractor, latch, firing device, and general working of all the varions parts are similar to those described with the preceding breech-piece. Conical Breech Block, with Shifting Action (Figs. 675 and 676).—This differs from the preceding type, as the block is slightly shifted in its support; moreover, the working lever is fitted to the lower part of the breech- block. The latter is slightly conical, and has four threaded 2 x