GB273338A - Electric fuses for explosive shells - Google Patents

Abstract

273,338. Rheinische Metallwaarenund Maschinenfabrik. June 26, 1926. [Convention date]. Reciprocating and oscillating machines.-A condenser charged by a current produced :n a coil by a sudden displacement of a permanent magnet on the discharge of the projectile or on impact is arranged to discharge through a variable resistance in series with an electric primer. The time required to bring the primer up to the ignition temperature varies acording to the strength of the current, which is regulated by the resistance. The arrangement therefore acts as a time fuze or a delay-action impact fuze. As shown in Fig. 1, the permanent magnet a is normally held in the forward position by safety springs b, which vield to the shock of the discharge. The setback of the magnet then causes a current in a coil d, which charges a condenser f. At the end of its stroke, the magnet a strikes a metal strip which breaks the circuit from the coil to the condenser and completes the circuit of the condenser through the body of the fuze, a screw t, a variable resistance r, a contact q, the wire o of the primer n, a screw m, and a lead l. The resistance r is an insulated coil of wire carried by a ring S set like the usual ring of ordinary time fuzes. In a modification, the primer is first heated by a current direct from the coil through a fixed resistance while the condenser is being charged, this current is cut off at the same time that the coil is cut off from the condenser at the end of the stroke of the magnet, and the heating is completed by current from the condenser through the variable resistance. In a further modification, a switch operated by momentum on impact short-circuits the variable resistance, causing immediate action of the primer if the time action has not yet taken place or has failed.