Patent GB-191115669-A (GB)
Title: Gyro-navigation Apparatus.
Inventor: SPERRY ELMER AMBROSE
IPC: G01C19/38
Filed: 1911-07-05
Granted: 1912-07-05
Abstract: 15,669. Sperry, E. A. July 5. Gyroscopic compasses.-Gyro-navigation apparatus comprises a gyro-wheel 1 mounted in a casing 2 with three degrees of freedom, the freedom of the gyro-wheel being positively suppressed in more than one plane (not in one plane only as formerly), by positively connecting the casing 2 to or controlling it by an element 17 which, although not forming an integral part of the gyro-wheel and its casing, is maintained in a practically stationary position relatively thereto by being caused to follow any apparent movements of the gyro-wheel about a vertical axis. A pointer 27<11> on the gimbal ring 19 supporting the gyro-wheel 1 registers with a compass card 27 carried by the element 17 and indicates any small amount of relative azimuthal movement between the gyro-wheel 1 and the element 17; this small movement can then be taken into account in reading the compass card 27. The gyro-wheel 1 is mounted in a casing 2 carried by horizontal pivots 21 in the gimbal ring 19 which is suspended by the bearings 20 in the element 17 and also by the torsion wire 18 which depends from a support resting on the top of the hollow stem 16' integral with the element 17 and guided by ball bearings 16 in the tubular hub 15 in the bracket 14<11> of the cardan suspension 14', 10. One method of suppressing some of the freedom of the gyro-wheel by maintaining a predetermined relative position between the gyro-casing 2 and the element 17 is to employ a pendulum 49 supported on the element 17 with its point of suspension 49<1> in alinement with the horizontal axis of tilt of the casing 2 and engaging the casing or an extension thereof loosely or allowing of some little freedom of relative movement between them at a point 49<11> to one side of the vertical axis (Figs. 1 and 13), so that the yielding positive connexion between the element 17 and the casing 2 is eccentric with respect to both the vertical and horizontal axes of movement of the casing 2. The power for driving the element 17 to follow the azimuthal movements of the gyro-wheel 1 and its casing 2 is derived from an electric motor 30, Fig. 9, the circuits of which are controlled by contacts 31, 32, Fig. 1, the movements of which relatively to one another are brought about by the relative movements between the gyro-wheel casing 2 and the element 17. The contacts and connexions for controlling the motor 30 are arranged in two or more sets each of which may be detachable. The cardan mounting 14<1>, 10 of the element 17 is provided with balance weights 71, Fig. 1, and the casing 2 is provided with a balance weight 71<1>, Fig. 3, a level and handles 45 to assist in determining the position of equilibrium and in setting the gyro - wheel in the same. The gyro - casing 2 is exhausted through the nozzle 8. The heat developed in the motor is dissipated by teeth 3" arranged on the inner wall of the casing to draw off the heat from the coils to the casing, exterior ribs 2<1> on the casing assisting radiation. The gyro-wheel 1 is mounted upon an easily-deflected shaft 4, the end bearings 5 of which comprise spherical surfaces and antifriction balls to accommodate deflexions of the shaft, these bearings being lubricated from receptacles 6 which are in constant communication through the pipe 7. A bearing 4<1>, normally out of contact with the rotating parts, is situated centrally with respect to and midway between the end bearings 5 of the shaft 4. To avoid disturbance of the position of the centre of gravity of the wheel 1 relatively to the casing 2 owing to expansion under the heat developed, the shaft 4 is fixed longitudinally at one end only, the lefthand end in Fig. 3, and the walls of the casing 2 are employed as an expansion compensator by making them conical and of such an angle that their expansion moves the fixed end of the shaft 4 away from the centre to equalize the expansion of this shaft to the right.