GB1534852A - Underwater detection equipment - Google Patents

Abstract

1534852 Sonobuoys ULTRA ELECTRONICS Ltd 20 Dec 1968 [23 Nov 1967] 53449/67 Heading G4F [Also in Divisions H3-H5] A sonobuoy for detecting objects, e.g. submarines, comprises a plurality of co-axial ring shaped magneto-strictive electro-mechanical transducer elements orientated in use with their longitudinal axis vertical and located in a parabolic reflector which is hinged to fold around the elements in transit, and a casing consisting of a nose cap, a lower section and an upper section, the nose cap forming a protective housing for a compass which is arranged to provide electrical signals representing the bearing of the median of the azimuth angle over which sonar signals are received. As shown, the compass 6 is sealed within the nose 1 by a bulkhead 7 on which is mounted a sonar receiver 8 comprising the transducer elements, the centres of which lie on a line coincident with the focus of the reflector 10. The reflector 10 is provided with hinged plates 11 which may be folded within the overall diameter of the sonobuoy. The compass 6 and the receiver 8 supply signals to an electronic unit 12 which amplifies the signals and applies them to a radio transmitter 13 by way of a cable which is coiled within a cable pack section 14 when the sonobuoy is not in use. A battery actuated by sea water is housed in a compartment 15. Paddles 16 are stored in a longitudinal position but in use pivot about a hinge 17 and extend outward to provide a reaction with the water when rotation gear housed in the compartment 15 is driven to rotate the reflector 10. The upper or flotation section 3 includes air drogues 18 which, on release of the sonobuoy from an aircraft, open to reduce its rate of descent. The air drogues 18 may be angled blades which rotate during the descent. On impact with the sea, a cap 19 on which the air drogues 18 are mounted is released to expose a compartment 22. A bag 23 within the compartment is inflated to extend a dipole aerial 24 within the bag. Section 2 parts from section 3 and descends to the limit of the cable. The paddles 16 automatically swing to a horizontal position and the hinged plates 11 spring open to form the parabolic reflector 10. While the section 2 is sinking a switch operates to start the rotation gear and to activate the compass and the radio transmitter. When the cable is taut, the sonobuoy is fully operational.