Patent GB-191000363-A (GB)
Title: Improvements in and relating to Automatic Guns.
Inventor: HAMMOND GRANT
IPC: F41A3/68
Filed: 1910-01-06
Granted: 1910-08-25
Abstract: 363. Hammond, G., and Darlington, T. Jan. 6. Breech actions, sliding breechblock. - Consists in a device for attachment to Springfield or other bolt - action magazine rifles to convert such rifles i n t o automatic rifles of the gasoperated type, the mechanism being readily thrown into or taken out of action so that rifles fitted therewith may be converted from single - firing to automatic rifles and vice versa The device is fitted to the barrel B, Figs. 4 and 9, by means of a sleeve 10 provided with a lug 11, in whicn there is port in line with a port 4 in the barrel, and communicating with a tube 13 screwed to the lug 11. A valve 12 controls the passage of the explosion gases from the barrel to the tube 13. A sleeve 14 surrounds the open-ended tube 13 and is connected to the tube 15, which is slotted to pass around the lug 11 and receives the power spring 16, and the buffer spring 17. A rod 21, Fig. 8, contained within the tube 15 bears at the front end against the lug 11 and passes freely through the opposite end of the tube. This rod is formed with a shoulder 20<1>, and sleeves 18, 19, carried by the rod, separate the buffer and power springs. After a bullet passes the port 12, Fig. 9, the powder gases enter the tube 13 and press forwards the sleeve 14 and tube 15 attached thereto. The sleeves 18, 19 also move forwards compressing the power spring 16; the sleeve 19 engages the shoulder 20<1> thus limiting the forward motion of the tube 15 and the compression of the springs 16, 17. The rod 21 has a piece 25 at its outer end to which is secured a tubular piece 28, Fig. 30, which, with a groove in the side of the receiver, forms a cylindrical bearing for the operating-rod 30, a pin r securing the piece 28 to the receiver. A bracket 32<Î>, Fig. 6, is secured to the tube 15, and supports a latch lever 33 pivoted at 34 and bevelled at the opposite end to be engaged by a lug 35 attached to the gun barrel, and also notched at 36 to engage the operating - rod 30. A sleeve 37 carried by the bracket 32<Î> forms a guide for the rod 30, which rod is hollow and contains a spring 31 in contact with a bifurcated piece 43, Fig. 22, attached to the coupling-pin r, a slot in the underside of the rod allowing for the full stroke of the breech-bolt. The rear end of the rod 30 has riveted thereto a solid rod 32. A piece 50, pinned to the rod 32, has its inner face milled to correspond to the face of the breech-bolt C, and is provided with a stud 50<1> engaging a groove k in the breech-bolt to lock and unlock the bolt. An incline on the piece 50 also forms a wedge to engage the lever 55 of the breechbolt to impart an initial lifting movement thereto when unlocking. A piece 56 pinned to the end of the rod 32 partly surrounds the head m of the firing-pin F. A sleeve 40, Fig. 4, is pinned to the barrel and forms a guide for the tube 15 and has an extension 42 bored out and slotted to receive the enlarged rear end of the casing 15 and the bracket 32<Î>. In operation, the tube 15 is pressed forwards after the bullet passes the port 4, and the latch 33 rises to the position shown in Fig. 6; upon the bullet leaving the barrel, the powder gases escape from the tube 13, the springs 16, 17 return the tube 15 and, throughthe medium of the latch 33, press rearwards the tube 30 and solid rod 32 thus unlocking the breech-bolt, opening the breech, and cocking the firing-pin. The spring 31 is compressed during this rearward motion, and the latch 33 is disengaged from the tube 30 by means of the fixed cam-piece 35 before the end of the rearward stroke, the momentum of the parts being sufficient to complete the stroke. As the parts return under the action of the spring 31, the rotary locking-motion of the bolt is started by means of the base of the lever 55 engaging a spring-pressed cam 88, thus disengaging the pin 50<1> from the square shoulder 54 of the cam-slot k. A special trigger-mechanism, and a device for holding open the breech when the magazine is empty, are also described.