Patent GB-987453-A (GB)
Title: Improvements in or relating to projectile fuzes
IPC: F42C9/14
Filed: 1962-02-06
Abstract: 987,453. Projectile fuzes. MEFINA S.A. Feb. 6, 1962 [Feb. 24, 1961], No. 4605/62. Heading F3A. A direct-action delay-or instantaneouslyoperating projectile fuze comprises a first striker pin 10, an axially movable primer carrier 14 housing primers 15, 16 separated by a pyrotechnic delay 17, a second striker pin 24 and a selecting device wherein the latter at one setting allows the primer carrier 14 to be entrained by the striker pin 10 upon impact so that the primer 16 is moved towards the second striker 24 for instantaneous detonation and at a second setting allows the first striker 10 to move towards primer 15 upon impact for delayed detonation and at a third setting prevents arming of the fuze. The primer carrier 14 has a forward extension 66 and is retained within a sleeve 18 by a frangible washer 19. A further sleeve 31, a ring 27 and the sleeve 18, which houses at its lower end a member 23 integral with striker pin 24 and a tube 25, are maintained in the unarmed position shown in Fig. 1 by a spring 33. The ring 27 is locked by a ball 39 and is releasably connected to the sleeve 18 by elastic members 28 whose lower ends engage a groove 30 in the sleeve. Before launching, the ball 39 is released by rotation of the selecting device which comprises head 2 to remove a screw 43 from contact with the ball to allow its entry into a slot 44, Fig. 2. On launching, the sleeve 31 and ring 27 set back, the former against the action of spring 33 and the latter against the gripping action of the members 28 which move from the groove 30 to a similar groove 38 in the sleeve 18. On cessation of positive acceleration the assembly comprising sleeves 18, 31, primer carrier 14 and ring 27 are moved forwardly by a spring 36 to the position shown in Fig. 6. The extension 66 on the carrier 14 comprises teeth 66a, 66b, Fig. 1, which form a bore 67, and the striker pin 10 comprises a head 68 grooved as at 69 and attached to a plunger 9 which is fixed to rotate with head 2, but is free to move parallel to the longitudinal axis of the projectile. The teeth and the grooved shape of the head 68 are so arranged that depending on the angular disposition of head 2 and hence head 68 with respect to the teeth 66a, 66b, either head 68 is free to move rearwardly on impact within extension 66 to cause pin 10 to detonate primer 15, or head 68 impinges on teeth 66a, 66b to break washer 19 and drive carrier 14 rearwardly on to pin 24 with consequent ignition of primer 16. The fuze is set before launching by rotation of head 2 to bring either one of two marks 73, 74, Fig. 2, thereon, corresponding to delayed and instantaneous ignition respectively, into registry with a fixed mark 45 on body 1. A primer 47 is mounted on an arm 49, Figs. 1 and 5, which by means of a clockwork mechanism acting on a toothed sector 53 is freed after a predetermined time to bring the primer 47 on to the longitudinal axis of the projectile. The primer is locked in this position by being pushed by a spring 62 into an aperture 63 which communicates with a detonator 26. The clockwork mechanism is initially locked by a rod 65 which abuts the tube 25 and is freed when the tube 25 moves forwardly to the position shown in Fig. 6. The fuze is primarily intended for projectiles having little or no spin during flight. When used with gyratory projectiles the clockwork mechanism may be replaced by a centrifugally-operating release device.