Patent GB-185162-A (GB)
Title: Improvements in the automatic control of the steering of ships, aircraft and the like
IPC: G05D1/02
Filed: 1921-05-13
Abstract: 185,162. Henderson, Sir J. B. May 13, 1921. Steering-gear.-A steering mechanism for sea and air craft comprises an element, such as a time-deviation integrator, controlled automatically by a deviation from the prescribed course and adapted to displace the rudder slowly until the deviation is corrected and to maintain the displacement thereafter to balance external forces tending to produce deviation. The element may be combined with other elements controlled in accordance with and producing displacement of the rudder proportional to the deviation and to the angular velocity of deviation of the ship. The mechanism is adaptable for changing from automatic to hand control. The armature of a motor 2, Fig. 1, is displaced step by step from a gyro compass proportionately to the deviation of the ship from its course. A similar motor 7 is moved by a constrained gyro proportionately to the angular velocity of the ship. These displacements are communicated through a differential gear 6 to a pinion 13 in another differential 14. A third motor 15 is displaced like the motor 2 proportionately to the deviation and moves the swash plate lever 18 of a Janney Williams or similar type variable-speed gear attached to a constantspeed direct current electric motor 19 whereby the pinion 23 of the second differential 14 is moved through a double-reduction gear proportionately to the time-integral of the deviation. The main pinion 24 of the differential 14 therefore moves under the combined influence of the three controls. This motion is transmitted through gearing a shaft 26 and a clutch to the ship's telemotor shaft 31 or other rudder-actuating mechanism. A handwheel 28 is carried by a shaft with bevel 30 thereon. By sliding the double bevel 33, 34 on the squared portion of the shaft 31 either the automatic or hand control may be coupled up. The fork for sliding the bevels also operates the switch of the supply to the transmitters actuating the motors 2, 7, 15 so that when the automatic gear is cut out from the shaft 31 it is also at a standstill. The automatic and hand gears have pinions which operate pointers 47, 48, so that when changing from hand to automatic control or vice versa the helmsman can ensure the two being in phase. In an alternative form the automatic and hand controls operate the pinion of another differential, so that locking one control results in the differential actuating the telemotor shaft from the other control. For obtaining a displacement of the motors 2, 15, from a gyro compass proportional to the deviation, a motor 77, Fig. 2, is employed which actuates through the wheel 79 of a differential 80, the drum 82 of the transmitter to these motors. The other element 81 of the differential is operated by gearing from a 'handwheel 91 for setting the required course. The motor 7 may be moved proportionately to the angular velocity from a constrained gyroscope. In obtaining the ship's angular velocity from a constrained gyroscope 100, Fig. 3, the latter is mounted on a fore and aft horizontal axis 101 and is constrained by a cantilever spring 103, motion of the axis being communicated by a lever 105 to a contact roller 109 resting on a two piece commutator 106 which is wired to a motor. The lever 105 also carries a pinion 110 driving a quadrant 114 on an arm depending from a shaft 111 which is geared to a transmitter 117. Motion of the transmitter is proportional to the angle of tilt of the gyro and this is proportioned to the ship's angular velocity. In a modification the gyro is used to give both deviation and angular velocity. In place of the hydraulic variable-speed gear a clock-work mechanism may be employed, a disc 159, Fig. 9, rotated at constant speed by clockwork has in contact therewith a roller 158 which is displaced radially by amounts proportional to the ship's deviation and can therefore rotate the flexible shaft 161 by amounts proportional to the time integral of the deviation. This shaft 161 puts into motion the motor 115 and transmitter 117 which is coupled to a motor on the shaft 26.