GB744564A - Projectile fuze, more particularly for anti-aircraft gun ammunition - Google Patents

Abstract

744,564. Projectile fuzes. SOC. PER AZIONI FRATELLI BORLETTI. Oct. 23, 1953 [Oct. 25, 1952], No. 29413/53. Class 9(1) A mechanical time and direct action fuze has a body 1 of light alloy externally threaded for insertion in the nose of a projectile and housing a clockwork mechanism M, a safety device S and a detonator assembly 3, 4 with a ball 5 obturating the flash passage. A graduated ring 6 is screwed on to the body 1 and above it is rotatably mounted an ogive 7 of light metal with a datum mark for setting the fuze. A key 8 fixed to the ogive is connected by pins 9 to the clockwork and shear wires 11 secure a sleeve 10 from which guide cylinders 12 extend into slots in the key. The percussion mechanism comprises a hammer 13 in contact with a, cylinder 14 adapted to operate a plunger 15 to actuate a lever 16 and plunger 17 attached by a member 18 to a striker 19. The clockwork mechanism M comprises an escapement for regulating a time bell 20 driven by a spring 21. During transport and handling, detonation is prevented by two pins 22 extending from a striker sleeve 23 to lock members 24, 25 bearing on the detonator housing 3. On firing the projectile, the sleeve 23 sets back due to inertia, compresses a spring 26 and engages with the capsule 3 thus freeing the members 24, 25. The lower member 25 moves outwards, its displacement being regulated by the mechanism S and the detonator capsule moves forward into contact with the locking member 24. The ball 5 then leaves its seating to free the flash passage. After a predetermined displacement of the member 25, e.g., corresponding to a travel of 100 metres of the projectile, the member 24 opens out, freeing the striker and detonator assembly. To set the fuze, the ogive 7 is rotated, simultaneously winding the spring 21 which is then held by a friction device. As the spring is wound, the time bell 20 is rotated through a corresponding angle, so that after a predetermined interval a centrifugal catch 27 moves to release a spring-loaded sleeve 28. On firing the projectile, the sleeve 10 sets back by inertia shearing the wires 11, the cylinders 12 moving along the guide slots until the sleeve becomes wedged locking the key 8 to the body 1. The released sleeve 28 is driven by its spring 29 against the striker 19, which then hits the detonator 4. Should the projectile hit a target before the set time has elapsed, a membrane 30 in the nose fractures, the hammer 13 is driven against the cylinder 14 shearing a retaining flange 31, so that the cylinder operates the plunger 15 to actuate the striker 19. Should the projectile impact laterally against a target, the detonator capsule moves forward against the striker due to momentum.