GB247265A - Gyroscope compasses - Google Patents

Abstract

247,265. Swinburne, J. Aug. 17, 1925. Gyroscopic compasses. - In a compass with a balanced gyro - casing, controlled by a level or plummet the tilting of which relatively to the casing operates a relay y controlling means for exerting torques around both the horizontal and the vertical axes, the level &c. also controls a creeping gear for slowly applying a uni-diirectional torque which remains until it is reduced or removed by the resulting tilt of the casing. This creeping gear is employed to apply corrections for changes of latitude and may be applied to a compass having an horizontal axis, or to a compass in which the axis is maintained parallel to that of the earth. The Figures show the application of the invention to a compass of the latter type, the gyro-casing A being pivoted about an horizontal axis B in the plummet element C which is pivoted in the vertical ring G. Secured by arms T to the element C is a plummet H carrying coils I in a magnetic field J. When the coils move within the field a current is induced in them, and this induced current is utilized to operate the torque-applying means and the creeping gear as indicated in Fig. 4. The gyroscope is driven by two phase cuirrent : the coils J are in phase 1 and when' the coils I are displaced a pressure is induced in phase 2. The coils I are in series with coils K, L in the field of a magnet M which is excited by phase 2 so that the current through the coils K, L produces a torque around the horizontal axis. The coils I also supply current to one phase of a two-phase motor N, the other phase being excited so as to produce a torque about the vertical axis. The creeping gear is operated by a two-phase motor F also receiving current from the coils I and operating through reducing gear a pinion gearing with a rack secured to the casing A to vary slowly the tilt of the gyro-axis, equilibrium being reached when this axis is parallel to that of the earth. In the case of a compass in which the gyro-axis is horizontal, the motor F may operate a rheostat in order to vary continuously the current passing through one of the coils K, L.