GB538049A - Improvements in or relating to fuzes for projectiles - Google Patents

Abstract

538,049. Projectile fuzes. FISHER, E. G. Jan. 18, 1939, No. 1804. [Class 9 (i)] [Also in Group XXXVIII] A fuze for anti-aircraft shells comprises a microphone controlling the actuation of a spring striker, whereby the shell is detonated when the microphone receives sound waves from the engine of an enemy aircraft, the fuze having first been armed by a wind-vane device after a predetermined time in flight. If the microphone circuit is not energized, the wind-vane device subsequently causes the actuation of the striker by mechanical means. The microphone 5 is located in the nose-piece 2 of the fuze, which is rotatable by wind-vanes 4 relatively to the fuze body 1. Extensible leads 8 from the microphone are connected to contact rings 7a, 7b on a nut 7 mounted on a screwed sleeve 6 carried on a frictionally-held contact plate 9. When, by the rotation of the nose 2, the nut 7 is caused to travel down the screw 6, it is brought into contact, after a predetermined time, with the contact rings 9a, 9b of the plate 9 and the microphone is thereby connected by brushes 10 and leads 11 to a source of current 12. The circuit includes an electro-magnet 20 and a make-and-break device 21a-21c. The electromagnet, when energized, lifts a spring-controlled striker 18 and compresses the striker spring 17. When the enlarged tail 15 of the striker has passed the weighted arm 21b of the make-and-break device, the latter is free to fall and open the circuit. The electromagnet is thus cut out and the striker is released and fires the detonator 19. If, after the nut 7 has made contact with the plate 9, no sound-waves are picked up by the microphone, continued rotation of the nose 2 overcomes the frictionlock on the plate 9 and the screwed sleeve 6 is rotated. This causes the downwards projection of a screwed rod 13, which is lightly restrained from rotation until a collar 13b thereon reaches the end 6a of the internallythreaded portion of the bore in the sleeve, whereafter the rod 13 rotates with the sleeve. The rod has a quick-threaded enlarged end 13a which enters a threaded bore 14 in the striker 18 and lifts the striker until the spring 17 sets up such a resistance as to cause the rod 13 to break and thus to release the striker and Explode the shell. The striker point is normally separated from the detonator by a pivoted shutter 22a. Retraction of the striker permits the shutter to be tilted out of the striker path.