Patent GB-635753-A (GB)
Title: Improvements in stabilising submarine signalling apparatus during the rolling of a vessel
IPC: B63B29/12
Filed: 1944-10-16
Abstract: 635,753. Subaqueous and like signalling- apparatus; electric follow - up systems. STEVENS, A. H. (Submarine Signal Co.). Oct. 16, 1944, No. 20000 [A Specification was laid open to inspection under Sect. 91 of the Acts, April 24, 1946.] [Classes 40 (i) and 118 (ii)] In a submarine signalling system for the transmission and reception of wave energy in a beam, automatic electrically-controlled means are provided for maintaining the directive axis of the transmitting and receiving means in a desired plane, e.g. the horizontal, during the roll of a vessel. As shown in Figs. 3 and 9 the high-frequency compressional wave sender and receiver 1 is mounted on a vertical rotatable tube 2 which may be projected through a ship's hull 3, and is free to rotate about a horizontal shaft 58 turned by a vertical shaft 61 inside the tube. The shaft 61 and tube 2 are operated through gearing by reversible electric motors, the one for the tube being shown at 7 in Fig. 3. The motor 7 is directly controlled by a relay 19, Fig. 1, and its direction of rotation by the two coils 25, 26 of a relay 24 which are energized by batteries 20 and 21 respectively through contacts 22 and 23 when closed by the armature 9. This armature is controlled by a polarized relay 8 comprising two windings 10 and two windings 11, each pair being connected in series with a battery 12. Also across the terminals of the battery 12 is a variable resistance having a manually adjustable arm 14 connected to the junction of the windings 10, and a variable resistance 15 whose contact arm 27 is connected to the junction of the windings 11 and is mechanically actuated by rotation of the tube 2, Fig. 3. The magnetic flux produced by the windings 10 normally balances that produced by the windings 11 and the armature 9 remains in the neutral position. In order to turn the part 1 to face in a new direction the arm 14 is moved to the corresponding position (as indicated on a scale) which upsets the balance in the relay 8 and closes one of the contacts 22, 23. The relay 19 is then energized together with the appropriate coil of the relay 24 and the motor 7 begins to rotate the tube 2. This operates the arm 27 to alter the flux produced by the windings 11 and the motion continues until balance is restored in the relay 8 when the armature 9 returns to its neutral position and cuts off the motor. The relay 8 may be replaced by a Wheatstone bridge. In order to compensate for the roll of the ship a similar circuit is used. The arm 27 is mechanically coupled to the shaft 61, and the arm 14 carries a pendulum and the resistance 13 is semicircular and rigidly mounted on the ship in a plane transverse to the fore-and-aft line so that as the ship rolls the resistance 13 will move over the arm, thus upsetting the balance in the relay 8 as before, the balance only being restored when the shaft 61 has been rotated the amount necessary to restore the directive axis of the part 1 to the horizontal position, i.e. when the arm 27 has been moved the appropriate distance along the resistance 15. Means may be provided for modifying the amount of unbalance produced by the roll of the ship, the arm 14 may operate through a cam. In order that the shaft 61 may be rotated in the right direction and to the correct amount, irrespective of the direction in which the part 1 is facing, the voltage impressed by the battery 12 on the resistance 13 is automatically reversed each time the direction of the part 1 is parallel to the fore-and-aft line of the ship by means of a cam switch (not shown) rotated by the tube 2, and this voltage is supplied through a potentiometer whose contact arm is coupled to the tube 2 in such a way that the voltage is a maximum when the directive axis of the part 1 is perpendicular to the fore-and-aft line of the ship and zero when it is parallel to this line.