Patent GB-815817-A (GB)
Title: Improvements relating to electrical fuzes for missiles, particularly rocket missiles
IPC: G04F1/08
Filed: 1956-05-14
Abstract: 815,817. Projectile fuzes. BRINRO Ltd. May 14, 1956 [June 1, 1955], No. 39838/57. Divided out of 815,815. Class 9(1) An electric projectile fuze comprises a condenser charged during firing of the projectile and adapted to be connected during flight to the internal firing circuits by an inertia switch, which switch includes a piston movable in a cylinder containing a damping liquid of substantially constant viscosity over a given temperature range. The condenser C 1  is charged by means of conductors 1, 2 and is arranged in series with an inertia switch I, an auxiliary switch IIc and a resistance R 6  of the order of several thousand ohms. The resistance may be replaced by a selenium or copperoxide rectifier, a germanium diode or a glow-lamp, and is intended to prevent accidental discharge of the condenser C 1  by short-circuiting. A resistance R 7  of the order of 10 meghoms is in parallel with the condenser C 1  to prevent undesired static charging of the condenser. Switches I and IIc are closed as in Fig. 1 during charging and open during arming of the fuze. When, after firing, the switch I reaches its final position, current from condenser C 1  explodes a primer Z to close main switches IIa, IIb and so complete the circuit to the cathode K of a triode T connected to a detonator D. A small capacity condenser C 3  e.g. 0.2ÁF when condenser C 1  has capacity 10ÁF, is placed in series with the primer Z, to prevent shortcircuiting of condenser C 1 . Accidental charging of condenser C 3  is prevented by a high resistance R 5  arranged in parallel. On closure of the switch IIa, a condenser C 2  in series with a resistance R 3  is charged by condenser C 1  and discharges through the detonator D when the triode becomes conductive. The condenser C 1  can then also discharge through the detonator when a shunt consisting of conductors b and c and short-circuiting resistance R 3  is put in circuit by closure of contacts A controlled by the member initiating the fuze, e.g. a striker. The potential of triode grid G is controlled by two resistances R 1 , R 2  connected to the condenser C 1  when switch IIa is closed, while a battery E heats the cathode K on closure of switch IIb to arm the fuze. On impact with a target, contacts A are closed thereby earthing the cathode through conductors b, c and shortcircuiting resistance R 3 , whereupon condensers C 1 , C 2  can discharge through the triode into the detonator. After a given time, if impact fails to occur, the detonator is fired by condenser C 2  charged to firing potential by condenser C 1 . Firing of the detonator, after closure of the contacts A, may be delayed by placing a resistance R s  in series with conductors b. c. When the fuze is to be initiated by a striker, the condenser C 1  may be shortcircuited by conductors c, d, e when contacts B are closed simultaneously with the switch IIc. This short-circuit may include a resistance R 4 . Contacts B may close as a result of damage to the striker and so prevent charging of the condenser C 1 . Condenser C 1  may be an electrolytic or a metallic paper condenser, whilst condensers C 2 , C 3  may be paper condensers housed in a common container, Fig. 2, above the detonator holder F. Specification 815,816 is referred to.