Patent GB-602304-A (GB)
Title: Improvements relating to guns and missile-projectors
IPC: F41A3/38
Filed: 1943-06-18
Abstract: 602,304. Guns. BLACKER, L. V. S. June 18, 1943, No. 9889. [Class 92 (ii)] Relates to semi-automatic breech loading guns or missile projectors of the kind having the barrel and breech-block sliding within a fixed casing and relatively to one another from the cocked positions in which they are independently held, and in which firing takes place during run out. According to the invention one or more locking members are mounted outside the barrel and breech-block assembly to move inwards during run out in order to engage between at least one rearward lug projecting outwardly from the barrel and at least one forward lug projecting outwardly from the breech-block, the member or members being moved out of engagement with the lugs during the return stroke. The gun shown comprises a breech casing 1 formed with a butt or shoulder piece 2, a barrel 15 slidable under the action of a spring 16, and a breech block 12 formed with a forwardly projecting tubular element 13 which surrounds the barrel. The spring 16 is arranged within the forward part of the tube 13 and bears at its rearward end on interrupted stops 17 on the front end of casing 1 and at its front end on the inside of a dust cover 18 fixed on the barrel. The tube 13 is slotted at 19 to clear the stops 17 and to allow the missile to be inserted in the breech chamber. The breech block is normally held in its retracted position against the action of two springs 23, housed in lateral chambers 25, by a spring-controlled sear 9 which is moved about its pivot by a rod 7 when the trigger 6 is pulled. The block when released moves forwards under the action of springs 23 and after. moving some distance two projections 53 formed on the tube 13 engage and depress levers 50 pivoted to the breech casing. These levers engage with pivoted sears 20 which are also pivoted to the casing and which normally engage with the forward shoulder of a skirt 22 formed on the barrel. Depression of levers 50 by projections 53 thus releases the sears 20 and the barrel moves forwardly under the action of spring 16. The barrel is almost immediately struck by the faster moving breech block and shortly afterwards the barrel and breech block are locked together. Such locking is effected by a pair of wedges 75, Figs. 2, 6 and 8, adapted to engage between the forward ends of slots 28 in the tube 13 and lugs 26 formed on the barrel skirt 22. The wedges are carried by arms 29 pivoted at 31 to a barrel reinforcement 32, and as the barrel moves forwardly the reinforcement tilts pivoted strikers 63 which thereby tilt rods 61 serving to move arms 29 inwards. The upper arm 29 has a nose 54, Fig. 8, which when depressed sufficiently by rod 61 rocks a sear 37 carried by a sear holder 38 in the breech block and thus allows the firing, pin 35, which is integral with a cocking bent 14, to move forwards to effect firing under the action of a spring 36. On recoil the barrel and breech-block move rearwards as a unit until the wedges 75 are released, the releasing being effected by rollers 33, mounted on the wedges, engaging with the forward ends of fixed ramps 66. The barrel is then held by sears 20 and the breech-block recoils alone. To ensure the recocking is effected even if the trigger is not released, a projection 67 on the recoiling breech-block engages a projection 41 on the rod 7 and moves the latter outwardly against spring pressure, This outward movement releases the sear 9 to engage and hold the retracted breech block. The latter carries a buffer spring 42 which engages an end plate 11 of the casing. A small lost motion is provided between the wedges 75 and the lugs thus enabling the breech-block to move slightly rearwardly relatively to the barrel on firing. During such movement the cartridge case moves backwardly in the chamber formed by the barrel skirt under the force of the explosive gases. Specification 602,322 is referred to.