Patent GB-516564-A (GB)
Title: Improvements in or relating to fuzes for projectiles
IPC: F42C15/16
Filed: 1938-04-29
Abstract: 516,564. Projectile fuzes. SAGEB SOC. ANON DE GESTION ET D'EXPLOITATION DE BREVETS. April 29, 1938, No. 12888. Convention date, May 4, 1937. [Class 9 (i)] Centrifugally-armed percussion fuzes, having a safety-device comprising a diametrically bored spherical body the axis of which is normally inclined to the projectile axis and is moved into alignment by gyroscopic effect due to the rotation of the projectile, are provided with means to effect the self-destruction of the projectile if it fails to explode by impact with the target. Fig. 1 shows a construction of percussion fuze in which the front pointed portion 8 of the striker is housed in the bore of the gyroscopic ball 6 which is held in the unarmed position by a spring-pressed sleeve 35 which accommodates the rear portion 4 of the striker and engages a cutaway portion of the ball 6. Balls 37 mounted in housings 38 on the sleeve 35 are adapted to engage under centrifugal action with a groove 39 in the fuze body, this groove being inclined at 40 in such a way that the centrifugal force of the balls 37 when applied thereagainst operates in opposition to the spring 17 acting on sleeve 35. In operation, on discharge of the projectile and after cessation of the positive, acceleration, the balls 37 move outwards and, bearing against the incline 40, raise the sleeve 35 against the action of its spring 17, thus liberating the ball 6 which, at the end of a predetermined time, brings the point 8 of the striker into alignment with the rear portion 4, thus arming the fuze. In the event of the projectile missing its target, automatic destruction ensues as soon as the component of the centrifugal force of the balls 37 becomes lower than the thrust of the spring 17, whereupon this spring drives the rear portion 4 of the striker against the front portion 8 which is thus forced into the primer (not shown). If desired, the bearing 36 for the sleeve 35 may be omitted, transport safety then being ensured by an auxiliary centrifugal bolt 10. Fig. 8 shows a modification in which a 'small striker 14 is mounted 'on a membrane 5 in the nose of the fuze opposite a primer 13 also mounted in the nose of the fuze, a resilient member 25 being interposed between the striker and primer. The self-destruction striker 8 in the ball 6 is made hollow so as to allow, in the armed condition of the fuze, transmission of the flash from the primer 13 to a second primer (not shown), on percussion. Modifications of the above arrangements are also described in which the means for the automatic destruction of the projectile are combined with the portion 8 of the striker within the ball 6, and also in which the striker portion 4 is omitted and the membrane - carried striker 14 is mounted at one end of the bore through the ball 6. The Specification as open to inspection under Sect. 91 comprises also a fuze, Fig. 1, (Cancelled), which is similar in construction to that shown in Fig. 1 above, but in which the means for the automatic destruction of the projectile is omitted. According to a further modification, Fig. 3 (Cancelled), a primer 13 is mounted in the ball 6 and is brought by the latter, in the armed position; into alignment with the striker 14. Modifications of this arrangement are described in which (1) the striker is mounted on a disc expanded into the nose of the fuze and yielding under the shock impact, a plug of elastic material being inserted, if desired, between the striker and the ball 6, (2) the striker is in the form of a corrugated membrane mounted on the nose of the fuze and engaging in corresponding corrugations in the ball 6 and (3) the striker is in the form of a membrane mounted directly on the ball 6 over the perforation holding the primer 13. According to still further modifications, the ball 6 may form a valve interposed between the primer 13 and the detonator. Fig. 6 (Cancelled) shows a construction of mechanical fuze of any suitable type in which 'the ball 6 contains a percussion pin 8. adapted to come into alignment by gyroscopic action with a spring-pressed striker rod 4 held in the unarmed condition by a retaining device 18 adapted to be withdrawn at the desired moment under the action of appropriate mechanism. Fig. 7 (Cancelled) shows a further construction in which the striker 4 is mounted to one side of the fuze axis and is held in the unarmed condition by a stop 20 adapted to be moved into a groove 21 in the ball 6 when'the latter reaches its armed position and thus release the striker 4: According .to a modification of this last arrangement, the stop 20 may be mounted in the flash-passage below the primer 13. A still further modification is described in which the striker and primer are both mounted in the ball 6 and are separated by a layer of cork, a spring or the like. Fig. 10, (Cancelled) shows a mechanical time fuze in which the primer 13 is located in the bottom of the bore 15 in the ball 6. into which the striker 14 is driven by a spring 17 when the ball 6 reaches the armed position. The pressure of the spring is regulated by means of a nut 29 engaging, on the one hand, with a screw-thread 30 on the body 1 of the fuze and, on the other hand, with the nose 2a of the fuze rotatably mounted on the body 1 and serving to turn the nut 29. An external scale permits the tension of the spring to be regulated so as to operate the fuze at the end of a predetermined time. It is stated that increasing the tension of the spring results in more rapid turning of the ball by the body 1 'and consequently in a reduction of the time at the end of which percussion ensues. An application of the invention to electrical fuzes is also described in which the ball 6 is made of insulating material and carries a ring of conductive material adapted at the end of a certain time to come into contact with a pair of terminals. Fig. 12 (Cancelled) shows a construction in which the ball 6, instead of being mounted in a spherical cavity, is simply held between bearings 31, a rod 32 mounted in the bore of the ball being adapted to establish communication between the head and point of the striker when the ball reaches its armed position. According to a modification of this. last arrangement, the rod 32 instead of being mounted in a ball may be adapted to slide in a ring mounted by means of a universal point in the fuze body. The application of the invention to a slow combustion time fuze is also described in which the ball 6 is mounted between two lengths of fuze beneath the primer 13. If desired, a pair of gyroscopic balls 14d, 14e, Fig. 22 (Cancelled), may be employed, the former carrying the primer 13 whilst the latter constitutes a valve in the flash passage, an elastic member, such as a split ring or spring, applying a certain friction to the balls which may be advantageously be held in the unarmed position by a spring-pressed bolt 10 adapted to be released by inertia on discharge of the projectile. Fig. 25 (Cancelled) shows a further modification in which the striker 14 is mounted on a resilient membrane 5 in such a manner that when the ball 6 is in its unarmed position, the striker is slightly raised and the membrane is bent. On the ball almost attaining its armed position, the resiliency of the membrane 5 tends to force the striker downwards into such a position that it engages in the orifice in the ball 6 thus preventing any further displacement of the latter. This subject-matter does not appear in the Specification as accepted.