Patent GB-524712-A (GB)
Title: Improvements in percussive fuzes for projectiles
IPC: F42C1/02
Filed: 1939-02-04
Abstract: 524,712. Projectile fuzes. ARBEY, M. L., REMONDY, G. H., and REMONDY, A. G. (Representatives of REMONDY, L. E.). Feb. 4, 1939, No. 3725. Convention date, Feb. 26, 1938. [Class 9 (i)] Relates to a percussion fuze having a fracturable striker of light weight as claimed in Specificafion 429,724 and consists in forming the striker as a simple nail having a large, thin and resilient head, the outer edge of which engages the front part of the fuze so as to close the latter more or less hermetically. As shown in Fig. 1, the head 2 of the striker 1 is applied to a shoulder 3 of the fuze body 4 and is held in place by a beading 5 of varnish or mastic, a certain space e being provided between the head 2 and the entrance of the passage 6 into which the striker projects and at the lower end of which is situated the percussion cap 7. On impact the head is deformed inwardly until it abuts against the plane surface 8 whereupon it is dissociated from the striker which thereupon advances and strikes the percussion cap. The sensitivity of the fuze may be increased by forming the head with weakening grooves or recesses or with an edge of reduced thickness. In order to increase the safety of the fuze, a compressible washer, e.g., of blotting paper or felt, may be provided in the space e, Fig. 6 (not shown) or as shown in Fig. 7 a washer 12 adapted to fuse under the heat developed by the friction between the projectile and the air during flight or to fracture under the action of centrifugal force, may be provided beween the head 2 and surface 8. Further, when it is desired to disarm the fuze automatically at the end of a certain time after discharge, the shoulder 3 may be formed as a strip 32, Fig. 7, of a readily fusible alloy. Heatconductive cores 33 of a metal, such as sodium, may also be provided to cause the heat produced by the friction of the air against the outer wall of the fuze to penetrate to the vicinity of the percussion cap so that; when this heating is sufficient, the cap will ignite automatically. When the obstacle encountered by the projectile is soft so that the reaction shock is insufficient to produce the dissociation or fracture of the striker, the striker head is given a convex shape, Fig. 8 (not shown) or is associated with a brittle auxiliary member, such as a washer, Fig. 10 (not shown), a cone, Fig. 11 (not shown) or a steel needle, Fig. 12 (not shown), or with a spring- pressed ball, Fig. 13 (not shown). Where it is desired that the fuze shall operate even in the case of low residual velocities, the weight of the stem of the striker is increased as shown in Fig. 14 by screwing or crimping an additional cylindrical or conical weight 21 on to the stem. Fig. 16 shows a simplified construction of fuze in which the striker is formed with a convex head, the edges of which rest directly on the surface 8, sufficient clearance being left between the edge of the head and the wall 25 of the fuze body to enable the head to flatten on impact. In a modification of this construction, a rigid washer is disposed in front of the striker head. Specification 456,300 also is referred to.