The invention relates generally to automatic machine guns of that description in which all operations of the mechanism are automatically effected by the energy of the recoil of the movable parts. The invention relates particularly to novel’ improvements. in recoil operated machine guns, similar to that disclosed in the Letters Patent of the United States granted to John Browning, No. 1,293,021, dated February 4. 1910, in which the barrel and breech closing block. while interlocked recoil together a limited distance, are then unlocked and the movement of the barrel is arrested; the breech closing block alone continues its recoil during which energy is .stored in reaction springs or similar means by Which all parts are finally returned to their forward firing positions. The main object of the present invention is to produce a machine gun of this class specially adapted for modern military service.
Experience during the war, and experiments since: under actual field conditions, have led the United States War Department to adopt for use in certain branches of the service, such as the Anti-Air Craft. Service and for service in tanks, bullets or projectiles greatly increased in caliber, length and weight, and cartridge cases of increased size capable of holding correspondingly increased charges of most powerful explosives for driving said projectiles and for giving to them greatly increased ranges and power of penetration. The machine gun of the present invention is adapted to fire these modern service cartridges; and while it has necessarily increased dimensions in diameter and length of certain of its parts, such as the barrel and breech mechanism, and of the lengthwise reciprocating movement of its breech opening and closing mechanism, these increases and the necessary strengthening of the entire structure of the machine gun are attained without a nearly proportional increase of the weight of said, machine gun.
This object is attained by providing a composite brake or buffer in rear of the heaviest recoiling of the breech mechanism, said brake consisting of the combination of a spring actuated recoil cushion combined with a brake chamber for holding a liquid by which any excess of energy of recoil is entirely absorbed; and by which even an excess of recoil, such as may possibly be caused by variations in the rate of speed of the ignition of the powder charges by the primers of the cartridges, will be absorbed without disastrous effect on I the structure or the Mechanism of said machine gun. For furthering the attainment of this object there are also provided in rear of the breech closing block cushioning devices for absorbing any excess of energy of recoil of said breech block; as well as devices for strengthening the breech casing of the machine gun supporting said cushioning de vices. Other and further objects and advantages will appear from the following disclosure. By the foregoing and other novel constructions which will be hereinafter fully described and pointed out in the appended claims, an improved machine gun is produced, adapted for firing the modern powerful military, ammunition, reliable, accurate! and absolutely safe under all conditions.
In the accompanying drawing’s: Fig. 1 is a side elevation of the left hand side Of the gun, the forward portion of the barrel and of the tubular barrel casing being broken away. Fig. 2 is a top view of the gun, the greater portion of the barrel and of the barrel casing being broken away. Fig. 3 is a front end view of the barrel; of the tubular barrel casing and of the internal fixed disk closing said barrel casing and guiding the muzzle of the barrel. Fig. 4 is a longitudinal section of the foremost portions of the barrel and the barrel casing, and of the internal fixed disk. Fig. 5 shows the pivoted switch lever, detached, respectively in a top view and in a left hand side view; it also shows similar views of the switch lever spring. Fig. 6 is a rear end view of the gun; Fig. 7 is a rear end view of the gun with the rear removed, showing the breech casing and the mechanism therein. Fig. 8 is a vertical transverse section through the breech casing on the line 88 of Fig. 12; seen from the rear. i Fig. 9 is .a vertical transverse section through the breech casing in the plane indicated by the line 99 of Fig. 12.