Patent GB-579806-A (GB)
Title: Improvements in and relating to torpedoes
IPC: F42C13/06
Filed: 1940-11-25
Abstract: 579,806. Controlling apparatus by sound. HUGHES & SON, Ltd., H., GASPER, P., HARRISON, E. P., and HUGHES, A. J. Nov. 25, 1940, No. 16895. [Class 118 (ii)] Relates to a torpedo of the kind which is controlled acoustically and explodes as it passes beneath the target without any material contact being made. According to the invention, the torpedo comprises magnetostrictive acoustic means for emitting an upwardly-directed beam of sound pulses which may be supersonic, magnetostrictive means responsive to downwardly-directed sound pulses and adapted to control the operation of a detonator, and means for preventing the energization of the receiving apparatus except by echoes produced by reflection from the target. The beam of sound pulses is emitted by a magnetostrictive device a, Fig. 2, composed of a pack of nickel laminations h, Fig. 3, insulated from one another and having a toroidal winding i thereon. The pack is mounted coaxially in a conical acoustic reflector k which is so mounted in the torpedo as to direct the beam of sound pulses vertically upwards. The reflector is housed within a waterfilled pan which has a cover u shaped externally to conform to the shell of the torpedo. The pan and the cover are clamped to the shell by bridles which engage flanges m, v. a sheathing n, w of resilient material being interposed to insulate the device acoustically from noises transmitted through the shell of the torpedo. The sound pulses are timed by a constant speed electric motor b, Fig. 2, energized by a battery, two contact drums q, s. being secured to the armature spindle. The drum q has a conducting segment r which makes contact with two stationary brushes 10, 11, and an adjustable brush 12. The drum s has a conducting segment t with two stationary brushes 13, 14. The magnetostrictive device a is set into resonant vibration by the application to the winding i. through the brushes 10, 11, of a succession of discharges from a condenser 15 which is charged by a battery 16 through a resistance 17. The device a also responds to the echo pulses, and when they are received, it generates an electric current which passes by way of the brushes 11, 12 throush the primary winding 18 of the input transformer of an amplifier. The position of the brush 12 is adjusted to allow the disconnection of the device a from the condenser 15 and connection to the transformer 18. To prevent the amplifier from being excited by the vibrations of the device a after the emission of a sound pulse, the drum s brings into operation a grid bias battery 26 which charges a condenser 25 prior to the emission of a sound pulse. At the moment of emission, the condenser biases the grid of the first amplifier valve 20 so that it is desensitized temporarily and renders the amplifier inoperative. Then the charge of the condenser leaks through a resistance 28 and the amplifier becomes sensitive when it receives the echo-produced currents from the device a. The output of the amplifier is rectified by a double diode valve 29, and the rectified pulses are impressed on the grid 30 of a gas filled triode 31 which operates an electromagnet 34 that complete the circuit of the detonator. Normallv the passage of the current through the valve 31 is prevented by giving the grid 30 a suitable negative potential by a battery 32 in order to prevent the operation of the valve by voltage pulsations resulting from noises not suppressed by the resilient mounting of the device a and the suppressive action of the condenser 25. The operation of the amplifier, and therefore the detonator by echo pulses reflected from the surface of the water is prevented by adjusting the position of the brush 12. Specification 579,805 is referred to.