Patent GB-561665-A (GB)
Title: Improvements relating to land mines or bombs
IPC: F42B23/00
Filed: 1943-01-23
Abstract: 561,665. Electric switches. PEARSON, F. F. A.; and MODREY, H. J. Jan. 23, 1943, No. 1180. [Class 38 (v)] [Also in Group XXI] A land mine or bomb capable of being laid either by aircraft, trench mortar or manually is associated with a source of electric current, and comprises a detonating mechanism and an electric conductor which, by distortion due to pressure, bending, or cutting, completes the circuit and fires the mine. The cable 10 comprises a central metal core 17 with spiked projections 18, cotton covering . 19 enclosed by an insulated covering 20, a helical metal armouring 21 surrounding the covering and an outer sheathing 22 of rubber or like protection which may be camouflaged. The helical metal armouring ensures that the cable will be resilient but will maintain its extended form when the mine is laid or discharged, and forms one arm of a battery circuit, so that when crushed or bent or cut, the circuit is completed through a detonator for firing the mine. The coil is provided at one end with an insulated sleeve 27 to which the central core 17 of the cable is hooked and at the other end with a spigot connector 15a adapted to enter a socket 15 in the mine so as to form a connection to the battery contained within the mine. The sleeve 27 is provided with a soft metal hook 26 adapted to be attached to a damper spring attached to the aircraft so that the pull of the bomb may deform the hook and release the bomb from the aircraft. In this case the spigot and socket connector to the bomb is of the undetachablekindas described in Specification 561,043 [Group XXXVI], which allows relative rotation without disturbing the electrical contact. The cable is normally coiled in a tail casing 22 attached to the mine and provided with clips 25 for the coil and tail fins 23 for stability during flight of the mine. The mine comprises outer and inner casings 1 and 3 between which the explosive material is positioned. The inner casing encloses a metal cylinder 4 and an insulating cylinder 10 which encloses the battery cells 8 and a detonator 9, and has attached to its upper end the socket 15 of the connector. Washers 11, 11a terminate the ends of the insulating cylinder and a metal disc 12 is interposed between the washer 11 and the cylinder. This disc is spaced from a disc 33 in connection with one terminal of the battery and the arrangement is. such that when the mine impacts with the ground a striking pin 29 shears a retaining pin 30 and drives the disc 32 on to the disc 33 and thus arms the bomb, so that when subsequently the cable is distorted by weight passing over it the firing circuit from the battery 8 is closed and the mine is fired as shown in Fig. 4 aligned apertures are provided in the cylinders enclosed within the inner wall of the mine and the wall to allow free passage of the gases to the explosive. When the mine is hand manipulated it may be necessary to render the mines safe after they have been deposited. For this purpose a time capsule may be incorporated to render the mine safe after an interval of time, or the plug of the connector may be removed by a tool comprising semi-cylindrical hinged members 38, 39, Fig. 9, having an inturned lower edge 37 adapted to be pressed into an enlarged hole in the mine containing the adaptor until the edge engages a recess 15e in the sleeve 15d of the adaptor, so that by prising the tool. upwardly the sleeve is raised and the spigot pin 15c is released.