GB748108A - Automatic pilots for ships - Google Patents

Abstract

748,108. Automatic steering control systems. SPERRY CORPORATION. Dec. 9, 1953 (Jan. 7, 1963], No. 34265/53. Class 38 (4). When a hand-operated lever 47, Fig. 4, is moved about a horizontal pivot axis 61 into the " Auto Pilot " position, switches 70, 73 are closed and relays 75, 77 energized so that a gyro-compass 1 controls a rudder 19 to maintain a ship on a set course. Under these conditions a D.C. step-by-step transmitter 5 associated with the phantom ring of the gyro-compass is connected to a repeater motor 7 geared to a potentiometer 13. Potentiometer 13 is associated with a rudderoperated potentiometer 17 to form a bridge circuit, output from which, on course deviation, operates relays 25, 29 through a magnetic amplifier 21 to start a motor 27 in the appropriate direction to correct course by rudder adjustment. Overall sensitivity is adjustable by rheostats 39, 39<SP>1</SP>, 43 and the amount of rudder correction corresponding to a given course deviation is adjustable by potentiometers 33, 331 in the bridge circuit. A generator 15 coupled to the transmitter 5 produces a component dependent on rate of change of course which is applied to the magnetic amplifier. The magnitude of this component is adjustable by rheostat 41. Slight adjustments of course to be maintained by the auto pilot may be effected by knob 87 adjusting repeater motor 7. For larger course adjustments lever 47 is temporarily moved to the " large course adjustment " position thereby de-energizing relay 75 and disconnecting repeater motor 7 from transmitter 5. It is then possible, owing to deenergization of repeater motor 7, to move lever 47 about a vertical axis 65 to operate potentiometer 13 manually. If lever 47 is moved to the " hand electric " position shown, relay 75 is de-energized to disconnect repeater motor 7 and permit manual control of steering motor 27 by movement of lever 47 about axis 65, and relay 77 is de-energized so that a rheostat 45 is substituted for rheostat 43 as sensitivity control, rheostats 33, 33<SP>1</SP> are shorted out, and feedback from generator 15 is disconnected. The mechanical arrangement of lever 47 is such that its movement between the " hand electric " and " auto pilot " positions is only possible if it is first centralized with respect to vertical axis 65. To prevent sudden change of course, closing of a main supply switch 97 is not effective to energize the apparatus until lever 47 is centralized to close a switch 97 and energize a self-holding relay 99. The construction of a steering stand incorporating lever 47, repeater motor 7, potentiometer 13, switches 70, 73, 97 relays 75, 77 and knob 87 is described. Specifications 154,618, [Class 38 (iv)], 669,696 and 727,673 are referred to.