Patent GB-159604-A (GB)
Title: Improvements in gyroscopic apparatus
IPC: G01C19/38
Filed: 1919-12-01
Abstract: 159,604. Henderson, J. B. Dec. 1, 1919. Gyroscopic apparatus for navigational purposes and having gravity control is provided with means whereby the gyroscope moves automatically from one steady state to another, when its mounting is subjected to accelerated motion. For this purpose an adjustment is provided to apply torques to the gyroscope or its gravity control proportional to the change of velocity, or to maintain torques which have been applied automatically by the acceleration, so that the gyroscope remains in a steady state when the acceleration ceases. The Figures illustrate the application of the invention to an aperiodic compass provided with a levelcontrol system. The gyroscope casing 1 is mounted on horizontal pivots 2, 3 in the ring 4 supported by the follower 20, which is carried by the spider 21 pivoted in the ring 22. The level control comprises the two liquid-containing vessels 7, 8 connected by the tube 9 and carried by a frame 23, which is pivoted at 24, 25 to lugs 26, 27 on the casing 1. A wire frame 28 fixed to the level carries a bracket 29 connected by springs 30, 31 to a bracket 32 having an internally-threaded lug 32<a>, Fig. 5, through which passes a screw 33 mounted in lugs screwed to the follower 20. The screw can be turned by a crank 34 operated by the arm 35 of a bell-crank lever which is secured to a spindle 37 journaled in brackets 38 on the follower. The arm 36 of the lever carries a roller 40 passing into a ring 41 mounted on horizontal trunnions 42, 43 in the spider 21, the trunnion 43 being secured to a crank 44 which is turned either by hand or automatically to incline the ring 41 to the horizontal at an angle proportional to the ship's speed. The displacement of the roller 40, and therefore that of the bracket 32 is consequently proportional to the meridianal component of the ship's speed. A very viscous liquid is used in the level, and the liquid displaced as the result of acceleration is consequently proportional to the change in velocity. This liquid is prevented from returning by the above-described adjustment of the point of attachment of the level to the follower, and the bore of the tube 9 is so adjusted that the torque exerted by the displaced liquid maintains the rotor axis in its new steady state. To obtain the necessary adjustment of the compass card, the spindle 37 is threaded and passes through a block 61 carrying a bracket in which is a screw 62<a>, Fig. 6, passing through a block 62<c> which carries a pin 62 engaging a radial slot in the card 60. The block 61 receives a displacement proportional to Vn, the meridianal component velocity, and the block 62<c> is adjusted by hand so that the adjustment of the card is proportional to V<n>/Cos A. The tilt of the level relatively to the casing 1, i.e. the deviation of the rotor axis from the virtual meridian, is indicated by a dial 63 on a drum 69 which is operated by a cord 67 attached to a rod 66 passing into the vessel 7. The lubber line is adjusted by hand according to the reading of this dial against a fixed index 72 on the casing 1. In applying the invention to a Sperry compass, one of the trunnions supporting the bail is horizontally adjustable in known manner for latitude correction and the other trunnion is supported from the bracket 32, or the screw adjustment may be replaced by an eccentric. The invention may be similarly applied to a periodic compass having a level-control system.