Patent GB-129724-A (GB)
Title: Improvements in or relating to Gyroscopical Direction Indicating Instruments.
Inventor: BREWERTON ARTHUR ERNEST
IPC: G01C19/34
Filed: 1917-12-08
Abstract: 129,724. Brewerton, A. E. Dec. 8, 1917. Gyroscopic compasses.-A gyroscopic compass for aircraft, motor-vehicles, &c., on which accuracy is required for relatively short periods of time, comprises a balanced gyroscope and a pendulous element adapted to be connected to the gyroscope, at a predetermined angle to the spinning axle, when the vessel or vehicle is stationary. The spinning axle is then set manually, or allowed to set itself by the action of the pendulous element, parallel to the earth's axis, the element being disconnected before the commencement of a flight or journey, so that the gyroscope has then three degrees of freedom, any errors arising from friction being corrected at the end of the journey by again connecting the pendulous element. The gyroscope may be driven electrically by alternating or direct current, and an electromagnetic connexion between the pendulous element and the gyroscope may be employed, the current being conducted through the pivots of the system. Friction about the vertical pivots of the system may be reduced by the employment of an electro-magnet to relieve the instrument of a part of the weight of the gyroscope. The gyroscope is mounted in a casing 1, Fig. 1, with its spinning axle in the direction a, b, the end b normally pointing north. The casing 1 is supported on horizontal pivots 2 in a vertical ring 3 supported in turn on pivots 4, 5 in a second vertical ring 6, which is made pendulous by an excess of weight in its lower part, and is supported on pivots 7, 8 in a ring 9 pivoted in the frame of the instrument. A compass card 23 carried by the ring 3 is viewed through a window 24 in the frame. The casing 1 is provided with a latitude scale 15 and carries a ring 16 provided with a spirit level 17 and a zero mark 18, the ring being clamped to the casing by one or more set-screws 19 with the zero mark 18 corresponding with the latitude in which the instrument is used. The electro-magnetic locking-means 22 for connecting the pendulous element 6 with the casing 1 is provided with a catch 21 adapted to engage a notch 20 in the ring 16, the arrangement being such that, when the pendulous ring is vertical and the catch engaged with the notch, the bubble of the level 17 is central. Current for the magnet 22 and for driving the gyroscope is conveyed through flexible connexions to spring contact fingers 26 engaging conductors 28, 29, 30, Fig. 4, set in an insulating-compound. These conductors are connected by leads passing along the rings to the magnet and to contacts 27, Fig. 1, on the pivots of the casing 1. The electro-magnet for relieving the vertical pivots of some of the weight is shown in Fig. 5. A disk armature 39 is carried by the vertical axis of the ring 3, the pivot 40 being adjustable to regulate the distance between the armature and the yoke 38 of the magnet. The tension of the spring contact fingers 26 may be made adjustable to introduce friction to damp oscillations when the pendulous ring is locked to the casing 1.