GB1308886A - Electrical fuse for projectiles - Google Patents

Abstract

1308886 Projectile fuzes PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 14 July 1971 [17 July 1970] 33056/71 Heading F3A [Also in Division H4] An electrical fuze for a projectile comprises a wire W which can be melted by applying a voltage across external contacts K and H, thereby eliminating a proximity fuze system and a selfdestruction system whilst maintaining an impact fuze system. With the wire intact all three systems are effective. The proximity fuze system comprises an oscillator OSC and an antenna coil L 1 for transmitting H.F. pulses to, and receiving a reflected signal back from, the target. The resulting Doppler signal initiates a thyristor T 1 which then causes a condenser C 1 to discharge through an igniter J. A transistor T 2 , in a high resistance state, enables the condenser C 1 to be permanently charged through a resistance R 1 . With the wire W melted, the oscillator is no longer earthed and is therefore inoperative, and the transistor T 2 becomes conductive and therefore prevents the condenser C 1 being charged. It is also possible to use other detectors in the proximity system, e.g. an infra-red detector. The impact fuze system comprises a contact A 1 which, when closed, permits a condenser C 2 , permanently charged through a resistance R 2 , to discharge through the igniter J or another igniter. A modified impact system (Fig. 2, not shown) includes two impact contacts coupled to coils. The selfdestruction system comprises a switch AD which is closed when the rotational speed of the projectile drops below a certain.speed or a timing device TP 1 for firing after a predetermined time. Alternatively a pulse generator TP 2 delivers a positive pulse to the thyristor after a certain time. The oscillator and charging circuits obtain voltage from a battery which is activated by the axial acceleration and rotation of the projectile.