GB586507A - Improvements in or relating to gyromagnetic compasses - Google Patents

Abstract

586,507. Gyro - magnetic compasses. THOMAS, I. L., and ROBERTS, G. E. March 15, 1945, No., 6603. [Class 97 (iii)] To eliminate errors due to inclination of the pendulous magnetic means, i.e. needle, earth inductor, or fluxgate elements, a switch or other means actuated by displacement of the gyroscope (with its spin axis lying in an E-W direction) relative to apparent gravity or to the gyro frame, retards or prevents the control of the gyroscope from the magnetic means, As shown, the precessing torque is applied by a coil 24 fixed to the vertical ring 25 and co-operating with a pair of arcuate permanent magnets 22 extending, with like poles adjacent, from the inner gimbal 23. Spaced resistance elements 52, Fig. 3, mounted on the ring 25 and connected as shown may co-operate with a contact arm 53 mounted on the gimbal 23 so that movement of the latter relative to the ring 25 first shunts with resistance 52 and then short-circuits the coil 24. In a modification, the coil 24 may be short-circuited by a relay operated by flow of current in the electric anti-topple means. In further modifications, the arm 53 may be replaced by a pendulous contact arm or the coil 24 short-circuited by a mercury switch mounted on the gimbal 23. Specification 586,506 is referred to.