The Works Of Messrs. Schneider And Co.

DISAPPEARING GUN CARRIAGES. trunnions that are carried direct by the brackets of the slide platform. (6) At its top part with cast-steel trunnion plates. (c) With a cross-piece, to which is joined the top of the recoil piston-rocl. Both cheeks are, moreover, fitted at their top part with an elastic buffer, which can rest, when the gun is completely run down, on buffers on the platform. The slide platform consista mainly of a plate caisson and two vertical brackets fitted with the trunnion- plates for the beam trunnions. It contains ail the parts of the inounting, narnely : The recoil cylinder, air recupe- rator, setting mechanism, pump for running down the gun, and it rests on a set of rollers on the bedplate. It is fitted also with uprights on which is fitted the horizontal shield, circular in shape, and in which is eut a longitudinal opening through which the gun passes in running up and down. The recoil cylinder oscillâtes round the trunnions carried on the flooring, in two fixed brackets ; the flooring is joined to the plate caisson, and is eut out in a suitable way to allow the recoil cylinder free travel in its oscillat- ing movements. The recuperator is in the rear, and is fitted with a collai- bolted on the slide platform. Com- munication between the recoil cylinder and the recuperator is insured through a pipe which ends on one side at the lower part of the recuperator, and on the other, on a valve ehest. The hydraulic piston-rod is joined to the beam by a cross-piece with trunnions ; the central counter- rod is fixed to the bottom of the recoil cylinder. The air recuperator contains an airtight diaphragm that divides it into two parts—the top division containing compressée! air, and the lower one, the liquid brought from the recoil cylinder. Through this diaphragm passes a rod provided with a stop to limit its travel. An air pipe allows the top division to be put in communication with the pressure pump, to run up the gun before firing, should the recupe- rator have been exhausted. When the gun is fired, it draws back the beam which turns on its trunnions to the rear, the hydraulic piston descends in the recoil cylinder, and drives the liquid into the bottom of the recuperator ; the movable diaphragm is displaced, and compresses the air of the top compart- ment. When the beam falls back, the air pressure becomes sufficiently high to balance the system, and the valve between the recoil cylinder and the recuperator falls on its seat. During the time the gun runs clown, the elevating rod that supports the breech end keeps the gun practically in a horizontal position, and when the motion ceases the gun is placed exactly in the required position for re-loading. The breech is then opened, the projectile and charge are introduced, and the fuse made ready ; the gun being given afterwards the required elevation and lateral training, with the help of the scales and marks provided for this purpose. For running up the gun again, the damp that holds the beam to the 277 slide is removed, and communication is re-established between the recoil cylinder and the recuperator by means of a special lever ; the compresse«! air expands, and drives before it the diaphragm which forces the liquid to return in the recoil cylinder, where it acts on the piston. The gun runs up progressively with a speed in relation to the space left free for the flowing of the liquid ; it can be lowered when necessary, with the help of a hånd- pump, which serves to force the liquid from the recoil cylinder to the lower coinpartment of the recuperator. The gun is given the required elevation Tby working the rod that supports the breech-end of the gun. The rod is jointed at its top part in a ring in the breech- end of the gun and on its lower end, on the elevating sector worked by a pinion keyecl on the working shaft, the latter extending outside the shaft in a box fitted with the working mechanism. This mechanism consista of a set of pinions and endless screws, driven by the shaft of the elevating handwheel. A pointer that travels along a scale shows the exact angle of the gun to the horizontal. Lateral training is given by a chain which surrounds the circumference of the bedplate, and passes round a pulley keyed on a vertical shaft ; tension Blocks serve to guide the chain. The cranked horizontal shaft drives the chain pulley, and produces the lateral displace- ments of the slide by tension on the fixed ends of the chain. A scale on the platform marks the extent of the lateral displacements. In normal service, the gun is trained when it is run down and loaded. As it may be necessary, however, to rectify the setting of the gun from time to time, when it is run up in battery, the shield is fitted with a special platform for sighting the gun on the target. The whole of the mechanism above described rests on rollers on the bedplate, which is bolted on the foundation. When a position has been chosen, the top of the foundation is made with a layer of concrète on which is placed an iron foundation-plate. These arrangements vary accord- ing to the nature of the subsoil. From the nutnber and diversity of types that we have notieed, it will be seen that the Schneider-Canet system contains mountings which can fulfil all the con- ditions required in service, from those for 75 milli- métrés (2.952-in.) guns, weighing 100 kilogrammes (2 cwt.) to those for the largest calibres. This section is of special interest, owing to the numerous unsuccessful attempts that have been made in several countries in the adoption of ordnance of this type. The designing of disappearing gun carriages, and their practical working, is a problem difficult to solve, at all events for large-calibre guns. The perfection to which the varions types of Schneider- Canet ordnance of this nature have been brought means, therefore, a large amount of calculation, trials, and tests of all kinds, carried through a number of years. 3 Q