IMPROVEMENTS IN OR RELATING TO GYROSCOPIC COMPASSES

1,205,065. Gyroscopic apparatus. VSESOJUZNY NAUCHNO-ISSLEDOVATELSKY INSTITUT GORNOI GEOMEKHANIKI I MARKSHEIDERSKOGO DELA. Aug.29, 1968, No.41283/68. Heading G1C. A gyroscopic compass comprises a casing 1 mounted on levelling feet 38 and supporting a theodolite 36, a sensing member 2 being suspended inside the casing 1 on a suspension strip 6, the strip 6 being made up by at least two laminated strips, providing a lower twisting torque on the sensing member 2 than if a single strip had been used. The sensing member 2 comprises a cylinder 4 to which the lower end of the suspension strip is secured, the upper end of this strip being carried by a gear 16 rotatable in bearings 23. Slip rings 33 and low-torque leads 34 are provided to conduct electrical power to the gyroscope spin motor 3. The clamp for the upper end of the strip 6 is mounted for pivoted movement about a horizontal axis on the gear 16 to allow for any slight misaligment and the movements of the sensing member 2 about the vertual are followed by the gear 16 using a follow-up system comprising a sensor 26 with a lamp 27 and two photo-conductive cells 28 co-operating with a mirror 22 on the cylinder 4, the sensor controlling a motor 24 for driving the gear 16. An autocollimator 37 cooperating with a further mirror 21 on the cylinder 4 is used for determining the angular position of the sensing member 2. The member 2 may be caged by means of two annular externally screwthreaded members 30, 31 having faces engaging upper and lower frusto-canial surfaces 5 on the cylinder 4. The members 30, 31 are engaged in a scew-threaded ring 32 rotatably mounted in the housing 1 and by rotating the ring 32 by means of a motor (not shown) the members 30, 31 may be made to engage and disengage the surfaces 5 as required.