Attached to the rear of the barrel (b) on either side are two side plates (h), between which in guides O works the aggregation of parts D, F, J, K, L, P, T and V, which constitute the lock, and (in bearings) the crank axle E, crank E′, and connecting rod I (see figs. 7 to 11).
The connecting rod I joins the lock and crank, being attached to the side levers J of the former by means of the interrupted screw U; the latter enables the lock to be detached and removed.
The crank axle E extends through both sides of the breech casing (d), slots (k, fig. 7), allowing it a longitudinal movement of about an inch. To its left-hand end, outside the breech casing, is attached the fusee chain Y of the recoil spring X (see dotted lines in fig. 7), and to its right-hand end a bell trunk lever, B B′; the arm B, which terminates in a knob, being turned by the crank handle, the arm B′ working against the buffer stop C.
In figs. 8, 9 and 11 the breech is shown closed, and it will be noticed that the crank pin I’ is above the straight line joining the axis of the barrel, the striker T, and the crank axle E. As the crank is prevented from further movement upwards by the crank handle B taking against the check-lever G (fig. 7), it is clear that the pressure on discharge of the cartridge cannot cause the crank axle to rotate, and so open the breech as shown in figs. 10 and 12.
The withdrawal of the lock and opening of the breech are effected as follows: The total travel in recoil of the barrel is about one inch, but on discharge the barrel, the side plates and lock all recoil together for about a quarter of an inch without any disturbance of the locking as explained above, and by the time this short travel is completed the bullet has left the muzzle. The arm B′ of the crank handle then engages the buffer stop C and causes the crank axle E to rotate and the crank E′ to fall and so draw back the lock from, and open, the breech. At the same time the fusee chain Y is wound up round the left-hand end of the crank axle E and the spring X extended. In the meantime the knob of the buffer handle B swings over, and just as the lock reaches its rearmost position (as in figs. 10 and 12) strikes the flat buffer spring H, and, rebounding, assists the crank in revolving in the reverse direction; the spring X also contracts, and, unwinding the fusee chain, draws back the lock again and closes the breech, a fresh cartridge having been placed in the barrel as explained below.
The gun is fired by means of the trigger F, which is actuated by the projection (l) on the trigger bar (S), the latter being drawn back when the button (m) on the push lever (n) is pressed forwards. If, therefore, the button he kept permanently pressed, the projection (l) will always lie in the path of the trigger F just as the lock reaches its forward position and the breech is closed, and the gun will fire automatically, and continue to do so as long as there are cartridges in the belt.
The loading, extraction and ejection of the cartridges are effected as follows: The left-hand side-plate is extended forwards a little beyond the breech, and communicates the reciprocating motion of the barrel to a lever on the feed-block, which causes the cartridges in the belt to be fed forward one by one by a “step-by-step” pawl action, the cartridge which is next to be taken from the belt being arrested exactly above the breech, the ejector-tube Q being below in the same vertical plane.
The extractor D (see figs. 9 to 12) which performs the operations of inserting, extracting and ejecting the cartridges, travels vertically in guides on the face of the lock. Projecting outwards from each side of its top are horns N (figs. 9 and 10). These travel round the edges of the cams M (fig. 8) situated on each side of the breech casing, and in conjunction with the spring W (fig. 8), compel the top of the extractor to take the path shown by the dotted lines and arrows in figs. 9 to 12.
| Fig. 9.—Maxim Gun Mechanism. |
The extractor (figs. 11 and 12) is recessed to take a movable plate (u) termed a “gib,” behind which is a spring (v). In the face of the gib is a recess (w) into which the base of a cartridge can just enter. On either side of the gib the face of the extractor has undercut flanges, open at the top and bottom, between which the base of a cartridge can fit the rim, being held in the undercuts (figs. 9 and 10).