Patent GB-147770-A (GB)
Title: An improved method and means for laying submarine mines by aircraft
IPC: F42B22/44
Filed: 1920-07-09
Abstract: 147,770. Kee, C. L. June 1, 1917, [Convention date]. Aerial warfare; mines, marine.-Consists in a method of laying submarine contact mines by means of aircraft, and involves the use of a detachable and sinkable parachute for retarding the fall of the mine through the air, and automatic means for anchoring the mine at a predetermined depth. Figs. 1. 2, 2<a> and 2<b> show the various stages of the descent of the parachute A, mine B, and anchor D. The mine is normally housed within the anchor framing, and parachute, mine, and anchor are held together by spring-actuated bolts 115, Fig. 3, which are released when, on striking the water, the anchor D is raised relatively to the mine by the buoyancy of a chamber C rigidly fixed in the anchor frame. The chamber C is slotted at 16 and perforated at 17 for the passage of the anchor cable 22, and as water enters the chamber through these openings, the chamber quickly loses its buoyancy and the anchor commences to sink. The parachute cords 2 pass to the releasable mine-supporting means through oppositely-disposed holes 6 in a hollow perforated ring 3, which, after the release of the parachute, floats for a short while, as shown in Fig. 2, then fills with water and sinks. Perforations 124, Fig. 2<a>, in the top of the parachute permit the trapped air to escape as the parachute is dragged down by the ring 3. The parachute is thus caused to sink and no. trace of the location of the mine is left on the surface. The winding-drum H for the anchor cable is normally locked by a spring- actuated bolt 43, Figs. 3 and 7, which engages in one of several notches 21 in an end disk 20 of the drum. The bolt is held in engaging position by the shank part 62 of a ball float E which detaches itself on striking the water and then fills and sinks. The bolt also frees an arm 49, pivoted at 51, which forms one support for a weight F around which a cable 58 is wound. The length of this cable determines in known manner the depth to which the mine B is to sink. Vanes 68 on the drum disk 20 retard the rotation of the drum, but the weight F falls freely. The inner end of the weight cable 58 is connected to a drumarresting arm 33, shown in plan in Fig. 6, which is pivoted at 34 and acted upon by a spring 35. This arm is normally held out of action by a vertical pivoted latch 27, the lower end of which enters a notch 36 in the curved portion of the arm 33. The latch 27 is pressed outwards by a spring (not shown) but cannot disengage itself until a gap 125 in the flanged edge 26 of a second disk 23 on the drum H comes opposite to a pin 29 on the upper extremity of the latch 27. The arm 33 has a vertical projection 37 which is adapted to engage with one of several teeth 24 on the disk 23, but this can only happen when the weight F touches bottom (as in Fig. 2a) and relieves the pull in the cable 58. The spring 35 then moves the arm 33 into the drum-arresting position, so that no more cable 22 is paid out and the anchor thereafter drags the mine down with it as it sinks to the bottom through the distance determined by the length of the weight cable 58. The mine B, shown in section in Fig. 14, is buoyant and the explosive container may rest upon a bed of sawdust or cork. The launching-tube on the aircraft is of aluminium, and the mine, anchor, &c. are retained in the tube by spring-supported latches which are released by pulling a cable. The Specification as open to inspection under Sect. 91 (3) (a) comprises also a chemical-mechanical means for exploding the mine when struck by a floating body, and chemical and mechanical safety devices to prevent premature explosion. The contact firing member comprises a spoked ring 72, Fig. 9, with a serrated edge, which ring is movably mounted between the mine-closing plate 76 and a top ring 74. At its centre the ring 72 has a triangular hole which fits over a similarlyshaped acid-containing bottle 81, Fig. 14, encased in gauze and a flexible leaden outer sheath. Displacement of the ring 72 breaks the bottle, and the acid flows downwards past a non-return valve 90 and acts upon an alkali 96. The gas generated lifts a piston 94 and cocks the firing-spring 101. Detent members 98 release the hammer spindle 100 as soon as they are lifted clear of a fixed block 97, and the hammer strikes upon a percussion cap 104 and fires the detonator charge 105 which explodes the main charge (T.N.T.). Premature movement of the firing-ring 72 is prevented (1) by spring bolts 107, Fig. 3, which are released by the action of the water on soluble retaining-pellets, and (2) by projections on the anchor frame members 12 which pass through the ring 72, 74, as shown in Fig. 9. This subject-matter is not described in the text of the Specification as accepted.