The Works Of Messrs. Schneider And Co.

XXX.—BREEGH BLOCKS FOR LARGE - CALIBRE GUNS. rIIHE classification of breech-blocks for rapid-firing -L large-calibre guns under a separate heading is justifiée! by the special arrangements required for manœuvring the heavy parts that constitute the mechanism. In the Schneider-Canet types of heavy breech-blocks, mechanism is used which the gunner can either control by direct action or the gearino’ of which contains a more or less iniricate series of transmissions that reduce the effort to be exerted within the limits of hand-power. This subdivision of large-calibre breech-blocks corresponds roughly to quick-firing guns and accelerated firing guns respectively. When the sizes of the parts to be operated make it expédient to bave recourse to mechanical motors, the work of the personnel is replaced by a steam, hydraulic, or electric motor, that generally forms part of the ship’s machinery ; in some installations accumulators are used, which absorb a more or less important part of the total power produced by the recoil of the gun. In such, cases, the gunners have only to manœuvre a distributør that acte upon a set of valves; hand levers are nevertheless provided, to be used for working the breech-bloek, should the motors fail to act. The following Schneider-Canet breech-blocks may be used with any type of obturator, whether plastic dise, metallic ring or cup, movable bottom or whole cartridge-case. Direct-Acting One-Motion Breech-Block for 20, 22, and 24-Centimetre (7.874, 8.661, and 9.449-In.) (Figs. 690 to 695, Plate CXIX.).—The sanie type of breeeh - block is applied to the three calibres. It contains generally the same mechanism as the breech- blocks for medium-calibre guns already described. The general views and details illustrate the working parts, which are so arranged that, by one single action of the liand lever, breech-blocks up to 9.449-in. calibre are quickly opened or closed. Section Fig. 690 shows the breech-closing device for a 20-centimetre (9.449-in.), 45-calibre Schneider-Canet quick-firing gun- It is designed for firing with a plastic obturator and by electricity. A bracket in the rear of the gun, which can be raised and lowered, facilitâtes charging (see Figs. 694 and 695, Plate CXIX.). Two-Action Breech-Block, with Firing Device for Friction Fuse (Figs. 696 to 698, Plate CXX.). — This illustrâtes the dass of Schneider-Canet breech-blocks, for the opening of which. several distinct actions are necessary. This mechanism comprises the breech-block with obturator and movable head, its bracket with the working mechanism, and the firing device. The breech-block is made with three threaded parts and three interruptions ; the obturator consists of a metallic disc centred on the movable head. The bracket consists of a horizontal plate, projections [ in which guide the breech-block in its longitudinal travel. ' This plate is in one piece with the part that passes over the hinge-bolt round which the whole system turns. The working gear is used specially for unscrewing the breech- j block ; it consists of a pinion fitted to the end of the lever, forged in one piece with the rear disc of the breech- block. This pinion engages in a circular rack fitted to the i rear end of the gun. A handle fixed to the pinion axis serves to turn round the lever, operating the bi*eech-block which is thus unscrewed. In the lower part of the lever is a groove in which travels, guided by a spring, a small ] tongue plate that mäsks the vent as soon as the opening J action is started. A fixed traction handle on the rear breech-block disc serves to withdraw the block, when it is unscrewed. A special double latch unites the bracket to the breech-block and to the gun alternately. Firing is I obtained by ineans of friction fuses placed in the vent. The tongue plate masks the vent so long as the breech is not completely closed, it is then impossible to insert the fuse, so there is therefore no risk of prématuré fire ; besides, as it is necessary, in the event of a miss-fire, to lower the tongue plate, and consequently to previously remove the fuse from the vent, there is no risk of acci- dentai firing. To open the breech, the tongue plate being lowered, the I lever handle is turned until the breech-bloek has travelled I through 60 deg., when the threads being disengaged, the block can be withdrawn and swung to the side by pulling on the fixed traction handle. When the breech-block I is completely swung back, the bracket latch engages a ' hook fitted to the rear end of the gun, and is held firm whatever be the incline taken by the gun, owing to the ! rolling of the sbip or to any other cause. An emergency ! mechanism, operated by a separate handle placed under the bracket, serves to insure regulär working should it be found difficult to withdraw the breech-block from the seating. To close the breech, the latch is released by hånd, I and the above actions are repeated inversely. Figs. 696 to 698, Plate CXX., show the breech closed, the breech-block unscrewed, and the block withdrawn from the breech. Three-Motion Breech-Block, with Percussion Firing- (Figs. 699 to 702, Plates CXX. and CXXL).—This differs from the preceding type, in that the block is swung to the side by means of a special mechanism. It consists of