The Works Of Messrs. Schneider And Co.

XXIX.-BREECH MECHANISM THE Schneider-Canet breech-closing- devices, thouoh comprising a large number of types, embody general characteristics common to all of them. They all have been thoroughly tested, and the varions types are adaptec! to f'ulfil the different conditions required for naval and land service. The designs of the breech mechanisms having been carried ont simultaneously with tliat of the whole material, it is necessary, in Order to form an idea of the important progress made, to pass in review successively the varions typical patterns that liave been manufacturée! and put into service. Until 1895 the Schneider-Canet guns were exclusively fitted with breech-blocks having interrupted screws. This system, and its many undoubted advantages over the wedge-closinç devices, are now well known, and we shall not enter into details on this point. It will suffice to remark in passing tliat every nation lias now adopted tlie breech-screw mechanism. Since 1895, Messrs. Schneider and Co. have put into service, after protracted experiments, an entirely new type of breech-closing arrangement, which is known as the “concentric threaded breech-piece;” this combines thegood qualities of the weelge and screw systems, without any of their disadvantages, In its most modern form, which has been evolveel from experience gained during the last twelve years, the Schneider-Canet breech mechanism combines the followino- advantages : Ease and rapidity in working. Excellence in the design of the varions parts composing the mechanism, and facility with which it is taken apart. Complété safety during all the varions phases of service. In the following descriptions we shall consider the principal types that embody special features separately, classifying them, for greater convenienee, according to the number of motions required to operate the complété opening of the breech. This will lead to an approximately chronological énumération of the varions types, corres- ponding generally to the dates of trial and adoption in service. The arrangement will, better than any other classification, enable our readers to follow the steady progress made in the Schneider-Canet quick-firing system with regard to the breech mechanism. The classification will therefore be as follows : 1. Three-motion types. 2. Two-motion types. 3. One-motion types. 4. Concentric threaded types. FOR QUICK-FIRING GUNS. 1. THREE-MOTION BREECH MECHANISM. We shall only describe a few specimens of the first type, as it was first adopted several years ago, and being now antiquated is only used for new guns when expressly specified, or when it is a question of completing existing armaments in a uniform mannet. The varions breech- pieces of this type differ one from the other in a few accessory details, the main parts being practically all similar. They have been applied to guns of all calibres, including those of 27 centimetres (10.530 in.), and in working they invariably gave satisfaction. One of the delicate parts of this dass of breech, the plastic obturator, has been carefully improved by Messrs. Schneider and Co. in order to insure its satisfaetory action under the varions conditions of service. The practical result has been a composite elastic obturator, which does away with all the difficulties that attended the use of those øf the ordinary kind. The five types illustrated by Figs. 618 to 634, Plates CXL, CXII., and CXIIL, consist each of a breech-block with interrupted screw, an obturator, and the firing device. The breech-block is made in three threaded parts and three interruptions ; it is carried on a bracket which pivots round a vertical hinge bolt. The obturator con- sists of a plastic elastic disc, placed between tlie movable head and the rear end of the breech-screw. To open the breech it is necessary (1) to lift the hand- lever in order to disengage the cam, and to give to the breech-piece one-sixth of a revolution with the help of the same hand-lever ; (2) to lower the lever in Order to dis- engage the obturator and to pull the block from the breech by taking hold of the fixed handle ; and (3) to turn it back to the side on the vertical hinge-bolt. To close the breech, tlie same motions are repeated in inverse order. Düring these varions operations a special slide-bolt, not fitted with springs, but acting on two combined inclined planes, unités the breech-screw to its support and the support to the gun alternately. The views we give reproduce the successive phases of opening the breech ; they show : 1. Breech closed. 2. Breech-block disengaged, lever brought down. 3. Extraction of breech-block. 4. Swinging of breech-block to the side. Type i (Figs. 618 to 621, Plate CXL).—This breecli- piece contains the following accessory devices : Firing is obtained by means of a friction fuse. During the opening motions, a finger worked by a cam, which forms one piece with the hand-lever, masks the vent until the breech is