Patent GB-689681-A (GB)
Title: Control apparatus for ship stabilising equipment
IPC: B63B39/03
Filed: 1948-10-29
Abstract: 689,681. Stabilising ships. POLLOPAS PATENTS, Ltd. (Montrose-Oster. L. E. W.). Oct. 31, 1949. [Oct. 29, 1948] No. 28125/48. Class 113 (i). The invention comprises control apparatus for ship stabilisation having at least three mechanical differential systems which may be levers having movable pivots. Each system comprising two input members and a differential output member arranged in pyramid form i.e. the second and third differential output members are connected tc the input members of the first. The input members of the second and third differential members are connected tc hydrostatic pressure units on opposite sides of the ship and to means for deriving a movement proportional to the angle of rolling of the ship and the angular acceleration of rolling. The totaliser shown in Fig. 4 produces the resultant of four influencing factors which displaces a slider 7 of a potentiometer 8 forming a part of a circuit fed with current of constant intensity, the output potential being combined with that of a dynamo 6 to control the operation of a regulator. The angle of rolling is detected by a gyroscope and is transmitted to the totaliser by a rod 9 pivoted at one end of the main lever 1 of the gyroscope and at its other end to a lever 10 forming part of the totaliser. The lever 10 moves about a fixed pivot 12 and is rigid with a double-armed lever 11 formed with a slot 13 with an adjustable slider 13a and connected to a rod 14. When the slider 13a is in the middle of the lever 11, rod 14 will not move when levers 10 and 11 are moved. When the rod is displaced towards one end of the lever 11 it will be moved in one direction when the arm 10 is moved, and if at the other end of the lever 11 it will move in the opposite direction for the same direction of movement of the arm 10. This arrangement enables the extent and direction of movement of the rod 14 for a predetermined movement of the rod 9 to be adjusted at will between a positive maximum to a negative minimum. The hydrostatic pressure on one side of the ship as indicated by the movement of the central point 51 on the spider 50 Fig. 3, is applied to one end of a lever 56 Fig. 4, of which the pivotal point 52 can be adjusted by moving the slider 53 in guides and locking in position. The other end of the lever 56 is pivotally connected to the central point 54 of the rocking arm 55. The lengths of the arms band c can be modified so that the movement of the pivotal point 54 for any predetermined movement of 51 may be adjusted. The upper ends of the rocking arms 55 and 55<SP>1</SP> are connected by rods 57, 57<SP>1</SP> respectively to opposite, ends of the rocking arm pivoted at 59 on the toothed quadrant 60 which can pivot about the axis 60<SP>1</SP>, the teeth of the quadrant 60 meshing with a pinion 61 which actuates the slider 7 of the potentiometer 8. The lower ends of the rocking arms 55, 55<SP>1</SP> are connected to the free ends of the rods 14<SP>1</SP>, 14 respectively. The three rocking arms 55, 55<SP>1</SP> and 58 constitute three differential systems arranged in pyramidal form. Specifications 458,747, 604,598, 644,605 [both in Group XIX], 689,682 and 689,728 are referred to.