Patent GB-299083-A (GB)
Title: Improvements relating to the automatic steering of dirigible vehicles
IPC: G05D1/02
Filed: 1927-07-20
Abstract: 299,083. Jackson, P. R., (Sperry Gyroscope Co.). July 20, 1927. Steering.-In automatic steering-gear for ships and aircraft the rudder actuation is automatically interrupted or slowed down when extraordinary yawing occurs. For automatic steering the master compass 1, Fig. 1, through a repeater motor 2 and differential 4, actuates a trolley 15 on an arm 3 which co-operates with contactor rings 10 in the circuit of the rudder motor 14. The motor 14 has a follow-up action through worm 26. Hand steering or alteration of the course is effected from the wheel 5 through the same differential 4 and a witch 40 is interconnected for preventing the slowing down action when the hand wheel 5 is in use. Coaxial with the ring 10 is a ring 13 with a broad central insulating strip and the arm 3 carries a trolley 16 coacting with the ring, so that the trolley does not, make contacts until greater angular oscillations arise. The motor 14 is controlled from the sections of the ring 10 through coils 19, 19<1> of relays 20, 21. The coil 19 controls switches 28, 29 for closing the circuit of the motor-armature for one direction and the coil 19' through switches 30, 31 cause opposite direction of running. For setting the speed of the motor, an adjustable rheostat 32 is used in the field circuit. Switches 22, 22<1> are also incorporated for action when the rudder quadrant 25 is hard over. A second resistance 33 in the field circuit is controlled from the ring 13 and is in operation in parallel with resistance 32 during large angles of yaw to slow the motor 14 and rudder movement. The motor is brought to rest dynamically by back contacts 35-38 which, when the circuit is broken, cut out the field resistances and short-circuit the armature through a resistance R. In a modification the motor is cut out entirely during part of the yaw. A primary set of trolley T and contactor ring C, C<1> and a second set of trolley T<1> and contactor ring C1, C<1>1, act through forward and reverse relays L, L1 on the motor 14, Fig. 4. The trolley T<1> is mounted with a slipping friction connection on the shaft 9 and has a limited range between stops S while the trolley T is fixed on the shaft and free to move over the whole angular range. Under the conditions of great yaw the action of the trolley T will be rendered ineffective during the part thereof in which trolley T<1> slips back on to its insulating central block between the segments C1, C1<SP>1>, and the motor will be stopped accordingly. Instead of driving the second set of contacts from the repeater motor they may be mounted on a gyro with two degrees of freedom and its spinning axis athwartships, precession being spring restrained. Precession beyond that due to normal yaw results in the contacts acting in the field circuit of the motor to slow it down or to stop it. Alternatively a vertical gyro with three degrees of freedom but pendulously mounted with a weight may be used. This gyro may have a third set of contacts to cope with excessive pitching conditions also. Specifications 214,215 and 265,246 are referred to.