Patent GB-151963-A (GB)
Title: Improvements in and relating to apparatus for locating or impairing the efficiency of or destroying enemy craft
IPC: F42B19/12
Filed: 1920-06-01
Abstract: 151,963. Browne, R. C. Sept. 29, 1919, [Convention date]. Ordnance for submarine discharge; discharging by means external to breechmechanism; ordnance, warrocket.-Consists in the pruvision of a submerged electrode and a submerged contact - member connected through a. galvanometer, relay, electric detonator, or other electric device, and so arranged that, when a submarine or other ship or like metal body touches the contact member, the ship or metal body co-operates with the first mentioned electrode and the sea water to form a battery producing a current through the galvanometer or other electric device, or annulling a current previously passing therethrough, whereby the ship &c. is destroyed by means of a gun or otherwise, or its presence or the presence of wreckage, is detected. The invention is described in detail mainly in connexion with submarine mines. Figs. 17 and 18 are views of a submarine mine provided with such electric firing-devices. The contactmember is a bare copper cable. 3 attached to a shackle 37 on an insulated spider 36 on the mine 9 and held distended bv a float: the electrode is an insulated disk 12; and these parts are connected to the moving coil 16 of a galvanometer comprising a permanent horseshoe magnet 65, pole-pieces 66, and armature core 67. The spindle of this core is connected to a cup 64 containing a metal ball 46 which is prevented from falling out accidentally by a guard 66<a>. When a current flows through the coil it is deflected or rocked, and the ball 46 drops down a tube 65 and lodges itself between two switch poles 47, thereby completing the circuit 10, 11 of an electric detonator 1. For safety, another switch is provided in the same circuit and adapted to be closed only when the mine is submerged to a given depth. This' safety switch has two poles 55, 55 and a movable bridge 54 carried by the plunger 56 of a hydrostat 59 to which water is admitted after dissolving a soluble packing 62. The plunger 56 of the hydrosstat is also connected to a lever 67 fulcrumed at 68 which serves to lock the moving coil 16 until the hydrostat is subjected to pressure at the given depth. In order to prevent earth currents from affecting the galvanometer circuit, a. plate 14 is provided beneath the electrode 12 and electrically connected bv the spider 86 to the contact cable 3 but insulated from the electrode 12. Earth currents caught by the cable 3 are then led out to the water by the plate 14 without passing through the galvanometer. In modifications of the above, (1) both electrode and contact-member are copper cables kept distended by a float; (2) the electric system, instead of firing the mine directly, causes the release of the mine from its mooring, the mine then rises along the contact cable 3 until it abuts against a stop thereon, whereupon it is fired in any suitable way; (3) rigid contact-pieces are arranged to project radially from the mine in various directions; and (4) the contact or both the contact and the electrode are constituted by nets supported by floats. In the apparatus shown in Fig. 21, the electric detonator 1 causes the discharge of a rocket 88 downwards from a submerged buoyant casing 74, and the rocket is guided downwards by the contact cable 3 and is exploded on impact. The detonator 1 first ignites a powder charge 87 which blows off a plug 96 releasing keys 94 serving normally to hold the rocket up. The ignition is then communicated to the rocket propellant cartridge 91 and the rocket expelled, the shock of expulsion being cushioned by the expansion of the gases into a tube 75. The rocket head 88 contains a high explosive 89 which is fired by a friction primer 98 when this is bent by the impact of a cone 97 against an obstruction. The rocket is guided along the cable 3 by means of a pair of tubes 100, 101 hinged together and provided with vanes 102, Fig. 22. The electrode 12 is carried by an insulating disk 85. The leads therefrom and from the cable 3 pass into the buoyant casing 74 through tubes 103, 105 containing waterproof packing, and the electric relay is contained in a box 30. In a modification, Fig. 24, the rocket 88 is discharged upwards instead of downwards and comprises two propellant cartridges 109 alongside the high explosive charge 89, a relay box 30 at the bottom, a spider 112 at the front end with a bevelled edge 113 to bite into the hull of the ship it strikes, and rudder blades 108 on a forwardly projecting tube 107 through which the contact cable 3 passes. The leads from the relay box 30 to the igniters 1 of the propellant cartridges are enclosed in tubes 115 fitted water-tight into the mouths of the cartridges 109. On impact, the high explosive charge 89 is fired through flash tubes 116 by the flame from the propellant cartridges 109. Normally, these flash tubes are closed by lids 118 soldered to the tubes 116 and provided with arms 119 extending into engagement with the rear ends of the propellant cartridges. These cartridges are carried by the spider 112 and on impact of this against a ship, they are moved back relatively to the main body 88, whereupon the lids 118 are forced open, and the high explosive is fired. In other applications of the invention, (1) an electrode cable and a contact cable are used to fire a gun at the ship that touches the contact cable or to give an indication of the presence of the ship, and (2) an electrode and contact cable are towed to locate a submerged submarine vessel or a sunken wreck. The Specification as open to inspection under Sect. 91 (3) (a) describes also a modification, shown in Figs. 12 (Cancelled) and 13 (Cancelled), in which the ship does not act as electrode, and instead, electrodes 24 are provided in closed chambers 25 on an insulated cable 3. When a chamber 25 is broken by contact with a ship, sea water is admitted to the electrode 24 and the galvanic battery and its circuit are completed. This subject-matter does not appear in the Specification as accepted.