Patent GB-166570-A (GB)
Title: Improvements in gyro-compasses
IPC: G01C19/38
Filed: 1917-06-23
Abstract: 166,570. Henderson, Sir J. B. June 23; 1917. Gyroscopic apparatus is constructed with the centre of gravity of the gyroscope and its gravity control system approximately on the trunnion axis of the gyroscope in its normal position, the control system being such as to apply a control couple proportional to the tilt of the gyroscope by a slow relative motion between the gravity control system and the gyroscope, a suitable form of control system consisting of a level the index of which moves very slowly against viscous or other resistance; the control couple may produce through suitable mechanism a component precession in the vertical plane through the rotor axis parallel to the above motion. Fig. 2 shows the invention applied to a gyroscope which is required to have its axis maintained at a fixed inclination to the horizontal. The gyro casing 1 mounted on horizontal trunnions 2 carries freely pivoted on a crank 8 a level consisting of vertical tubes 11, 12 connected by a tube 13 with a stopcock for controlling the passage of the fluid; Fig. 20 shows a valve comprising a loaded spring diaphragm 82 for preventing flow of liquid due to acceleration. The level is connected to the gyro casing 1 by springs 16, 17, and a couple about the vertical axis of the member carrying the trunnions of the gyro casing is produced by means illustrated in Fig. 3. A triangular block 23 is mounted on a lever 18 rigidly connected with the level and is normally opposite the central aperture of the trunnion 2 from which issues an air-jet produced by the rotation of the rotor in its casing. When the gyroscope tilts from its normal position with respect to the level, the airjet exerts more force on one side of the block 23 than on the other, the couple about the vertical causing precession about the trunnions 2; in the arrangement shown, the air-jet tends to increase the tilt of the level, but by pivoting the block 23 in a part mounted on the trunnion the air-jet may be arranged to decrease the tilt of the level. Other constructions of level are described, comprising curved tubes and balls or rollers, two-liquid forms, and forms in which a lever carrying the lever 18 is actuated by floats in the liquid. Fig. 10 shows a form in which the gyro casing 1 has its axis kept vertical by means of a level 11, 12, 13 carrying vanes 43, 44 acted upon by air-jets 47, 48. A similar set of levels &c. is arranged at right angles to the first. A gyro-compass with horizontal rotor-axis is shown in Fig. 12, the level 12 being mounted on a shaft 49 pivoted in lugs carried by the gyro casing 1. The torque about the vertical is introduced by means of an air-jet from the trunnion 2 acting upon a pivoted block, which is mounted on a lever 18 and is similar to block 23 described in connection with Figs. 2 and 3; alternatively, the torque about the vertical may be introduced by twisting the suspension wire by attaching the contact-roller of the following- mechanism to the lever 18 on the level of the trunnion 2. In the construction shown in Fig. 14, the torque about the vertical is derived directly from the gravity couple due to the level 11 by means of a fork 61, formed on the end of a lever 59 rigid with the level tube 13<A> and engaging with an eccentrically disposed pin 61 on the gyro casing 1. In all the arrangements described above, the gyro is in gravitational instability due to the level. In the arrangement shown in Fig. 17, the gyroscope is in gravitational stability and the level acts as a relay to control the stability mechanism, a. shutter 78 carried by the level 11, 12, 13 controlling air-jets 68 driving a rotary pump 64 to vary the level of fluid in vessels 62, 63 on the gyro casing, and so to weight the casing more on one side than on the other. In the construction shown in Fig. 21, the level 11 produces no direct couple on the gyroscope but only a restoring-couple about the vertical. An air-jet 82 from the gyro casing 1 normally delivers air centrally through a. hoppershaped shoot 80 open at the bottom; tilting relative to the level causes the jet to impinge on one side of the hopper, which is not on the centreline of the gyroscope, so that a couple about the vertical is produced. In the construction shown in Fig. 24, a couple about the vertical tending to annul the tilt causing it is produced by the reaction of air-jets issuing from nozzles 88, 89. which are parallel and in the same direction. The air-jets pass through bells 86, 87 in the vertical tubes 11, 12 of the level and are differentially throttled by the fluid when the level is tilted by the gyroscope.