Handbook for Light Artillery

by A. B. Dyer

ACTION OF THE MECHANISM.

In [Fig. 89] cd, c′d′ are the developments of the right-and left-hand sides of the elliptical groove; cc′ and dd′ are developments of the circular arcs.

When the crank is rotated, it causes the shaft with the barrels, carrier-block, and lock-cylinder to rotate in the casing. The bolts, held by the guides in the surface of the lock-cylinder, also rotate with the barrels and other parts, but by the bearing of the bolt-lugs in the elliptical grooves in the barrel-casing the bolts on the right-hand side are forced to move forward, dc, towards the barrels, and those on the left to move backward c′d′.

When each bolt in this rotation reaches the "loading-flat," a cartridge drops from the feed into the groove in the carrier-block, in front of the bolt. As the rotation continues the bolt pushes forward until, on reaching the "firing-flat," the cartridge has been completely inserted and the barrel closed. During this motion a groove on the right-hand side of the casing, R, catches the head of the firing-pin and retains it, thus compressing the spiral mainspring and cocking the firing-pin. A continuation of the rotation causes the firing-pin to pass out of this groove; and the action of the mainspring drives the pin forward and fires the cartridge.

The motion continuing, the bolt is withdrawn by the left-hand groove, c′d′, and as it moves backward the empty case is drawn out by the extractor on the bolt.

THE FEED.

The Bruce Feed ([Fig. 90]).—This is a gravity feed consisting of an upright bronze standard, a, having two grooves in it. Below the grooves is a fixed mouth, c, and below this a wheel, d, having its axis to one side of the mouth and turning freely on this axis.

When in use, the feed is inserted in an opening in the barrel-casing directly over the carrier-block, e. The paper box containing the cartridges (the top being removed) is placed in the fixed standard with the heads of the cartridges to the rear. The heads engage in the grooves of the swinging-piece, b, and the paper box may then be pulled off. As each cartridge strikes the wheel it causes the latter to revolve and present a new groove for the reception of a cartridge. The cartridges delivered to the wheel are in turn carried around by it and deposited in the grooves of the carrier-block.