Patent GB-740195-A (GB)
Title: Improvements relating to projectiles and particularly hollow charge projectiles
IPC: F23Q3/00
Filed: 1954-01-25
Abstract: 740,195. Ammunition projectiles and fuzes therefor. AKTIEBOLAGET BOFORS. Jan. 25, 1954 [Jan 27, 1953], No. 2170/54. Class 9(1) A hollow charge projectile provided with an impact-operated electric nose fuze comprises an electrically conductive casing 1 forming part of the connection between an impact actuated front member and the ignition means housed in a rear member. The casing has a screw-threaded connection to the liner 2 of the explosive charge 31 The threaded cylindrical part of the liner projects beyond the casing to receive the threaded end of the cap 3 into which is screwed the head 4 containing a piezoelectric device. Within the head a sleeve 5 lined with insulating material 6 surrounds fivesuperposed cylindrical members. 7-11 the lower members 9-11 being apertured to receive an electric cable 12 which passes through a guide sleeve 13. The member 7 is electrically conductive and in conductive contact both with the sleeve 5 and the member 8 which may be a piezo crystal. The member 9 is also electrically conductive and is connected to the cable 12 and the member 8, while the members 10, 11 are preferably of insulating material. The cap 3 has an insulating liner 14 covered by a conductive layer 15 to which the cable 12 is connected. A spring contact 16 connects the layer 15 to a conductive layer 17 overlying a non-conductive layer 18 on the liner 2, while the layer 17 is connected by a conductor 20 to a conductive layer 22 separated by an insulating layer 23 from the casing 1. Into the projectile base is screwed a plug 24 containing an igniting composition 25 and an igniter 26 connected electrically to the plug and to the layer 22 by a leaf spring 27. A screwed member 24a facilitates assembly of the plug and the ignition means. The layers 15, 17, 22 may be made of foil or formed by spraying, and the casing 1, cap 3, sleeve 5 and plug 24 must be electrically conductive. A filling opening 29 is closed by a plug 30. In a modification. the layers 14, 15 and 17, 18 take the form of annular bands the contact 16 being elongated. When the projectile hits a target, mechanical stresses set up in the member 8 produce a voltage which is discharged through the igniter 26 and causes ignition of the composition 25. In Fig. 3 the cap 3- is made of insulating material, two electric conductors being cast therein. One conductor is wire netting 33 riveted to the contact 16 and cable 12 and the other is parallel wires 32 protruding from the ends of the cap. The wire ends may be cut off and metal contact plates fitted. Both conductors may be parallel wires or wire netting or single core cables. In modifications the various layers may be omitted from the walls and a cable extend from the member 9 through an insulating sleeve in the liner 2 and the charge 31, whence it passes out of the casing and into the plug to connect with igniter 26. The voltage source 39 in Fig. 5 is a dry battery or accumulator housed in the base plug. The member 8 is replaced by a spring 36 holding apart contact studs 37, 38 on the members 7, 9. A cable 12' connects the member 9 to the igniter 26 which is in circuit with the battery 39. On impact, the circuit is closed by the contacts 37, 38. The conical liner 2 may be integral with the casing 1 or joined thereto by welding.