Patent GB-379134-A (GB)
Title: Method of and apparatus for determining, independently of sight, the true horizon ofa moved system
IPC: G01C19/44
Filed: 1931-10-15
Abstract: 379,134. Gyroscopic apparatus. GES. FUR ELEKTRISCHE APPARATE, Marienfelde, Berlin.-(Assignees of Boykow, J. M. ; 2A, Fontanestrasse, Lichterfelde, Berlin.) Oct. 15, 1931, No. 28710. Convention date, Oct. 15, 1930. [Class 97 (iii).] The invention relates to a three gyroscope system for determining the true horizon independently of sight and makes use of the fact that the precession of the pendulous horizon gyroscopes, which depends on the rotation of the earth, the inclined position of the system, frictional and other resistances, and the rate of movement of the system itself, may be represented as a speed vector which when compared with the rate of movement of the system as determined by other means enables the inclination of the gyroscope system to be determined. Alternatively, if the difference between the rate of movement determined by the gyroscopes and that determined by other means is the same for observations made at different times the gyroscope system is known to lie in the horizontal position since its inclination must h a v e remained c o nstant. According to the invention the precession of two gyroscopes (horizon gyroscopes) of a three gyroscope apparatus and the position of the third gyroscope (azimuth gyroscope) are transferred to a setting device in the form of magnitudes and directions respectively of the components of an apparent speed. In the form shown, the gyroscope carrying frame 14 is pendulously mounted for rotation about a vertical axis 20 in gimbals 18, 19. The two horizon gyroscopes 11, 12 preferably compensated for the effect of rotation of the earth, are supported in the frame 14 by pendulous frames 15, 16 and have vertical precessional axes and perpendicular horizontal axes of rotation. Alternatively they may have vertical axes of rotation and perpendicular horizontal precessional axes. The azimuth gyroscope 13 is supported in the frame 14 by a frame 17 and has perpendicular horizontal axes of rotation and precession. The arrangement of the gyroscope 11, which is substantially identical with that of the gyroscope 12, is shown in Fig. 2. The frame 15 is attached to the frame 14 by horizontal bearings 24 and a spring 15<1>. The vertical axis 28 of the gyro casing carries a contact arm 29 adapted to wipe contacts on a toothed sector 30 which is freely mounted on the axis 28 and caused by the pinion 31 of the reversing motor 32 to follow the movements of the arm 29. The pinion 31 also drives a sector 33 carrying a contact arm 34 adapted to wipe contacts 35, Fig. 4, on a sector 37, which is freely mounted on the axle 36 of the sector 33 and is connected by a centralizing spring 42 to the frame 15. To ensure a good contact between the contacts 34, 35 the sector 37 carries an armature 38 arranged between the poles of an electromagnet 39 which is brought into operation by closure of the contacts 34, 35 and causes the sector 37 to move up to a stop in a direction opposite to the movement of the contact arm 34. Closure of the contacts 34, 35 also operates an electromagnet or electromotor for moving transversely to the frame 15 a weight 44 adapted to produce a turning moment about the axis 24. Oscillation of the frame 15 is damped by a liquid brake 48, 49. The vertical axis 20 of the frame 14 carries a gear wheel 51 meshing with the pinion of a reversible motor 52 mounted on the ring 18 and controlled by a contact arm 74 on the precessional axis of the gyroscope 13. The setting device, Fig. 4, comprises two spindles 53, 54, rotatably connected under the control of the electric motor 58. The spindle 54 carries a nut 57 the distance of which from the motor 58 may be adjusted to represent the speed of the system as indicated by a speedometer by the hand wheel 60 or, if desired, by an electric motor. The spindle 53 is driven by the planet wheels 64, 65 of a differential gear the bevel wheels 61, 62 of which are driven by motors 68, 69, controlled respectively by contacts 34, 35 and a transmitter 77 driven by the motor 32. A nut 56 on the spindle 53 is accordingly moved in accordance with the precession of one of the horizon gyroscopes (say 11). A contact rail 55 extending between two contacts 70, 71 on the nut 56 is attached to the nut 57 and its angular position relative to the spindle 54 is controlled by a motor 59. The motors 58, 59 are operated by a transmitter 76 driven by the motor 52, which is controlled by the azimuth gyroscope 13, so that the angle alpha between the spindles 53, 54 and the angle # between the spindle 54 and contact rail 55 are maintained complementary. Movement of the nut 56 from its central position relative to the control rail 55 closes one of the switches 70, 71 bringing into operation a rectifying relay 45, 46, Fig. 2, for applying a torque about the vertical axis of the gyroscope 11, a similar relay 78 for the azimuth gyroscope 13, and operating a movable damping weight 79 for the gyroscope 11. A similar setting device which may however have the spindle 54 in common with the first setting device is provided for the second horizon gyroscope 12. The electrical control of the setting device may be replaced by hydraulic or pneumatic means.