GB687135A - Improvements in indicating, measuring, recording and control instruments and devices - Google Patents

Abstract

687,135. Gyroscopic apparatus. METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. April 4, 1950 [Feb. 17, 1949], No. 4394/49. Class 97 (iii). [Also in Group XXXII] A gyroscopic apparatus provided with a resilient mounting 17, Fig. 1, has the gyroscope as a whole statically balanced about two perpendicular axes, the mounting 17 having neutral axes coinciding with the balancing axes so that linear vibration will be transmitted to the gyroscope through the resilient mounting solely as linear movements. In a rate of turn gyro the rotor 1 is mounted in a gimbal 2 which is pivoted in bearings in end plates 5, 6, the latter forming with a pair of plates such as 8, an open ended box. Plates 5, 6 are bolted to supporting plates 14, 15, recesses 12, 13 therein, receiving spigots 5a, 6a, on the end plates. In balancing the open-ended box about axis B-B it is spun in a dynamic balancing machine provided with centres to which the plates 5, 6, are bolted and recessed to receive the spigots. Similar spigots such as 8a are provided on the side plates for balancing about a perpendicular axis. Adjacent each plate 14 and symmetrically arranged around the axis B-B, are four rubber cushions 17 bonded to metal plates 18 rigid with plates 14, 15, and bonded to plates 19 which have screw-threaded bores for receiving bolts 20 passing through the casing 16. When the supporting craft turns about an axis perpendicular to both the gyro spin axis and axis B-B, the gyro precesses about the latter axis under the control of spring 10, an electromagnetic pick-off 9 indicating the precession. Two pairs of dashpot cylinders 25, 25a, mounted on plates 26, 27, secured between the plates such as 8, provide damping about the axis of turn. The plungers in each pair of dashpots are connected by stiff flexible wires 28, 28a, extending through diametral holes in bolts 29, 29a, and secured thereto by nuts and washers, the bolts 29, 29a being rigid with lugs 30, 30a secured to the casing 16. Diametrically opposite dashpots may be connected by conduits to prevent linear damping along the axis B-B. Vibration of the gimbal 2 is damped by a device 11 comprising an annular casing 39, Fig. 3, secured to plate 5 having blocks 44, 45, fastened by screws 46 to its inner surface. Resilient bellows 47, 48, 49, 50 extend between the blocks and the arms of a metal member 40 fast on the shaft 43 supporting gimbal 2. The bellows 47, 48 and 49, 50 which contain oil, silicone or other damping fluid are connected by passageways 51, 53, in the blocks, needle valves 52, 54, controlling the damping, whilst bellows 55, 56, secured to the blocks and connected with the passageways allow relief of excessive pressure. Passageways 59, 60 may be provided in the member 40 for connecting diametrically opposed bellows for pressure equalization in the event of unequal adjustment of the needle valves. In the embodiment described in the Provisional Specification the dashpot cylinders are mounted in the end plates.