The Works Of Messrs. Schneider And Co.

CLOSED-IN TURRETS FOR 15- AND 20-CENTIMETRE G-UNS. 251 section for the 12-centimetre guns. The mounting and slide rest on a platform, which also carries the armour. Under the platform is bolted the ring, to which the central socket is attached. The whole of the turret is carried on a hydraulic cylinder, that forms a pivot, and is fixed to the bottom frames of the ship. The gun is elevated by hånd power, by means of a crank and a pinion ; the latter works, through two bevel wheels, a hélicoïdal wheel, and an entliess screw the shaft, on which is keyecl a square pinion which engages the toothed sector fixed to the carriage. A jointed sight- line follows the gun in all its displacements. Lateral training is obtained by hånd or by electric power, the displacement of the gun being produced by the rotary motion of a pinion which gears in a toothed ring fitted therefore be stopped during the time required for taking a cartridge from the carrier. The hoist is worked by hånd or electric power through pinion and bevel wheels, which drive the shaft carrying the chain wheels. Closed-In Turret for 20-Centimetre (7.874-In.) Gun (Figs. 840 and 841, Plate CXLIV., and Figs. 842 to 845). —In this type the gun is mounted on a carriage, the arrangements of which, as well as those of the slide which supports it, are similar to those of the corresponding parts of the 15-centimetre (5.91-in.) gun just described. The slide rests on a turning platform which carries the pro- tective armour ; the top part of the central tube for the passage of ammunition ends on the right-hand side of the platform. The tube is guided at two points along its height by rings of vertical rollers. It is fitted ou tside with Schneider-Canet Turrets for 15- and 20-Centimetre Guns. round the central socket, the pinion being worked by a hélicoïdal wheel and an entliess screw. In operating the mechanism by hånd, the shaft carrying the entliess screw is put in motion by two bevelled wheels worked by a crank and a plate-chain. When electric power is resorted to, the hélicoïdal wheel is worked direct by a dynamo and two pinions. The motor is controlled by a cylinder called cartouche électrique, the working lever of which is within easy reach of the gunner. Ammunition is raised to the platform by a hoist that consists of two plate-chains, United at intervals by gun- inetal saddle-pieces. At the lower end of the tube the cartridge is placed in a special carrier, in the bottom part of which is fitted a lever; this moves under the action of the saddle-piece, lifting up the cartridge and placing it ready for hoisting up the tube. A treadle worked by the gunner on the top platform throws the mechanism of the hoist out of gear when neeessary ; the hoist can a circular rack for lateral training, and inside with the guides for the hoist. The whole rests on a hydraulic cylinder, forming a pivot. The elevating mechanism is governed by hånd, by means of a handwheel, that actuates gearing, and a toothed rack fixed on the left side of the carriage. Lateral training is effected by hånd, or by electric power. The motion is obtained by the rotary action of a pinion which gears in the circular rack fitted to the central tube ; the pinion is keyecl on a vertical axle worked by a hélicoïdal wheel and an entliess screw. The mechanism is driven by a series of friction rings placed in the thickness of the helicoidal wheel. In operating the lateral training device by hånd, the shaft on which the helicoidal wheel is fitted is set in motion by two square-toothed pinions which engage those keyed on the handwheel axles. When electric power is resorted to, the dynamo works a square pinion which transmits its motion to the driving axle through