Patent GB-374318-A (GB)
Title: Improvements in or relating to grenades
IPC: F42B12/42
Filed: 1931-07-22
Abstract: 374,318. Projectiles ; smallarms. BRANDT, E. W., 101, Boulevard Murat, Paris. July 22, 1931, No. 20957. Convention date, July 25, 1930. [Classes 9 (i) and 119.] Relates to grenades adapted to be discharged from the muzzle of a firearm by a bullet fired from the firearm entering a tubular recess in the grenade. According to the invention, the tubular recess 12a, Fig. 1, decreases stagewise in diameter from the rear towards the front, and the tube 12 within which this recess is formed is attached externally to the base of the grenade 1, for example by a cotter pin 13 which is sheared by the shock of discharge, so that the tube 12 falls off when the grenade leaves the firearm. The grenade is provided around the tube 12 with a tubular tail-piece 7 fitted with vanes 20 to stabilize the flight of the grenade. This tail-piece fits snugly around a muzzle extension 8 formed with annular grooves 11<1> which act as gas seals. The extent to which the muzzle extension 8 fits into the tailpiece 7 is limited by a stop 66, Fig. 4, provided with a spring catch 69 which can engage any one of a number of holes 70 in the extension 8 according to the range desired. The extension 8 is attached to the muzzle 9 by a bayonet-like joint. In a modification, the range is varied by masking or unmasking lateral outlets at the rear end of the muzzle extension 8 by means of a rotatable ring. The Specification as open to inspection under Sect. 91 (3) (a) describes also two constructions of fuzes for the nose of the grenade. In one form, Fig. 3 (Cancelled), the detonator 34 is held in its casing 35 by a thimble 36 formed with an aperture 37 closed by a wad 38. The casing and the thimble are crimped together at 39 and are secured between a shoulder 42 on the fuze body 30 and a washer 43. The fuze body itself secures in position the flange 33 of the housing 32 for the detonator 35. The percussion cap 46 is secured by a collar 47 in a thimble 45 locked by balls 48 to a tube 44 extending between the washer 43 and a cup 55 confined by a shoulder 57 on the fuze body. the balls 48 are confined by a sleeve 50 normally held in place by a lip 54, and the firing-pin 53 is normally held forward against the shoulder 57 by a spring 56. When the grenade is discharged, inertia causes the firing-pin to set back temporarily, but this cannot make it reach the percussion cap, and the spring 56 soon returns the firing-pin forward. Inertia also causes the setback of the sleeve 50, after which, during flight, the balls 48 fall off their seats and the percussion cap in its holder creeps forward within reach of the firing-pin when this is driven in on impact. The time occupied by this forward creeping arming operation depends on the length of the stroke and the frictional resistance. An elastic member of variable strength may also be interposed between the thimble 45 and the washer 43. Further safety may be provided by making the point of the firing-pin comparatively soft and covering the percussion cap with a comparatively hard disc. In a modification, Fig. 8 (Cancelled), the percussion cap 46 is fixed to the tube 44, and the balls 48 prevent the setback of the firing-pin 53 until after discharge the balls 48 released by tHe setback of the sleeve 50 creep out of the way. The firing-pin is in this form hollowed out to increase the sensitiveness to impact. This subject-matter does not appear in the Specification as accepted.