Patent GB-157427-A (GB)
Title: Improvements in and relating to submarine mines
IPC: F42C14/04
Filed: 1921-01-10
Abstract: 157,427. Stockum, A. J. van. May 15, 1918, [Convention date]. Void [Published under Sect. 91 of the Act]. Mines, marine.-Relates to submarine mines of the kind in which a hydrostatically-actuated firing- striker is released by a. pawl when external feelers are struck by a ship, and consists mainly in opposing the action of the striker by an adjustable spring which renders the mine safe when not sub. merged, the adjustable spring acting on the striker through the pawl and being withdrawn from action with the pawl when overcome by the hydrostatic pressure. As shown, the striker 3, Fig. 1, pivoted at 4 is connected by a link S to the hydrostat 10 and is held cocked by bearing with a roller 32 on a pawl 17, which is pivoted at 33 on a lever 18 and interlocks with a notch 31 in a bar 21 jointed at 34 to the lever 18. The bar 21 is guided by a slot 23 on a pin 22 on a bracket 24, and is controlled by a spring 25 which can be adjusted by varying the position of its abutment 27 by shifting a pin 28 from one hole to another of a set of holes 29 in the bar 21. The lever 18 is pivoted at 19 to a bracket 20 and is held at safe by the end 38 of a lever 34 pivoted at 35 on the bracket 20 and connected by a pin 36 to a plunger 37, which is normally held down by a strong spring 40 and is raised when the external feelers are struck by a ship. For this purpose, the plunger 27 carries a cross-piece 41 the ends of which fit in vertical slots in the rim 42 of a cap 42' and in wedge-shaped slots in blocks 43 on a ring 44 loose around the rim 42. The ring 44 has a number of radial arms 58. Each arm is bent out at 60 and is there jointed to one end of a lever 56 pivoted at 57 and jointed at the other end to a ring 45 rotatably mounted on a kneebracket 49 around the mine. The ring 45 carries a number of arms 46, Fig. 5, which are released by soluble plugs 47 on submersion and are then swung out about pivots 51 by springs 48. The return of the arms is prevented by the interlocking of dents on the arms and on the edges of the slots in the ring 45 through which the arms move out, this interlocking being brought about by a deflexion of the arms from their normal plane under the influence of the springs 48; to permit this deflexion, the pivots 51 are made a loose fit in their respective arms 46. Any impact on these external parts causes the ring 44 to rotate and the cross-piece 41 to be wedged up by the slot in the blocks 43. The plunger 37 is drawn up with the bridge-piece and swings the lever 34, thereby releasing the lever 18 and allowing the pressure on the hydrostat 10 to overcome the spring 25. While the bar 21 moves to the left and the lever 18 rocks in a clockwise direction, the pawl 17 is lifted from the notch 31 and releases the striker 3, which then swings freely on to the percussion cap. The hydrostat chamber 12, Fig. 4, is connected by a pipe 13 to an open chamber 14 at the bottom of the mine. The pressure is thus transmitted by a column of air to the hydrostat which does not come in contact with the water, and is therefore kept free from incrustation.