GB1101956A - Meridian seeking gyroscopic instrument - Google Patents

Abstract

1,101,956. Gyroscopic apparatus. TOKYO KEIKI SEIZOSHO KABUSHIKI KAISHA. June 22, 1965 [June 26, 1964], No. 26348/65. Heading G1C. A meridian seeking gyroscopic instrument for use in surveying comprises an outer casing 7 rotatable in bearings 9 on a base-plate 6, a rotor case 11 having shafts 12, 13 mounted inside the casing 7 for rotation in bearings 23, 24 and supported by a suspension wire 14, the rotor in the case 11 rotating about an axis O, and the upper end of the wire 14 being secured to an arm 28 having gear teeth engaging with a worm 29 which can be rotated manually by use of a knob 30, a differential transformer 36 connected to a meter (not shown) being provided to monitor relative angular deviations between the gyro case 11 and the outer case 7. In use the outer case 7 is rotated to produce a null output from the differential transformer 36, and the knob 30 is used to ensure that at this position no torque is applied to the gyro case 11 by the wire 14. The wire 14 may be a piano wire or any derived metallic wire or band, or non-metallic strip or thread of e.g. nylon. At the lower end of the shaft 13 a rotary member 26 is provided, immersed in a viscous liquid 25 to damp movements of the gyro case 11. The instrument must be adjusted before use to align the wire 14 and shafts 12, 13 in a vertical direction and this is carried out using screws 10 on the base-plate 6. The outer casing 7 carries an index mark (not shown) for co-operation with a similar mark on a transit theodolite mounted above the casing 7.