Patent GB-790019-A (GB)
Title: A combined gyroscopic artificial horizon and directional gyroscope
IPC: G01C19/02
Filed: 1955-10-14
Abstract: 790,019. Gyroscopic apparatus. ANNEN, R. Oct. 14, 1955 [March 2, 1955], No. 29296/55. Class 97(3) [Also in Groups XXIX and XXXIV] A combined directional gyroscope and artificial horizon consists of a ball-like rotor supported and propelled by a gas; a bearing of which an upper portion is transparet and which is fixed to a casing of the gyroscope; a floating bearing composed of two juxtaposed hemispherical caps of which the centre of gravity is situated on the common axis of the two caps and the shifting with respect to the centre of the sphere defined by the caps, such floating bearing being supported by the gas in the fixed bearing so as to be angularly movable in any direction with respect to the latter from a determined position in which the centre of gravity of the floating bearing is positioned vertically below the common centre of the rotor and of the floating bearing; means for limiting the angular shift of the floating bearing with respect to the fixed bearing from the determined position in all directions; means for binding the floating bearing to the spin axis of the rotor while permitting the bearing to move freely with respect to the spin axis by pivoting about an axis which is set at right angles to the spin axis and also to the common axis of the two caps of the floating bearing and which passes through the common geometrical centre of the rotor and of the floating bearing; a mark on the equator of the rotor visible through the upper transparent portion of the fixed bearing and the upper transparent cap of the floating bearing; and indicating means carried by the casing, movements of the latter means with respect to the equator of the rotor indicating the variations of the position of the casing with respect to the spin axis of the rotor.. As shown in Fig. 1, the housing 2 of a turbo compressor, having an electric motor 5 driving an impeller 6, is fixed to the casing 1 of the gyroscope. The casing 1 has a central vertical bore 7 adjoining a horizontal annular shoulder 8. At half the height of the bore is a peripheral groove 9 which is constricted, but not interrupted, by two projections 10 (Fig. 4). Groove 9 communicates with the central portion of the turbo compressor through a bore 11, and with the atmosphere through a duct 12. Duct 12 is covered on the outside by two filters 13 attached to a pivoted hood 14. Spaces 15 are provided for lightening the box 1, and further spaces 16 are formed above and below groove 9 and receive through holes 17 compressed air - from the turbo compressor. The fixed bearing consists of two cap-shaped covers 19 and two cap-shaped bushings 21, 21<SP>1</SP> which are held against the flanges 18 of the covers 19 by two rings 20, the whole assembly being held in the bore 7 by a securing ring 22. In each cover-and-bushing asembly is formed a cap-like recess 24 connected to the corresponding opening 16 through a number of radial holes 25 and a peripheral groove 26 in each flange 18. Each of the bushings 21, 21<SP>1</SP> has on its inside surface a number of recesse 27 (Fig. 2). Compressed air from the spaces 21 is admitted to each of the recesses 27 by a hole 28 fitted with a nozzle 29. By this means, a floating bearing formed by two hemispherical caps 30, 30<SP>1</SP> is supported in the fixed bearing. The air is collected in a groove 31 formed on the inner surface of the rings 20, and thence escapes through radial ducts 32 to the groove 9, whence it is led by duct 11 towards the turbo-compressor. The lower cap 30<SP>1</SP> is made of metal, and the upper cap 30 is made of a transparent material such as polystyrene. The upper bushing 21 and the upper cover 19 are also made of transparent material, while the lower bushing 21 and the lower cover 19 may be made of metal. The lower cap 30<SP>1</SP> is made of metal in order that the centre of gravity of the floating bearing may be situated below its geometrical centre. A pin 33 is provided at the centre of bushing 30<SP>1</SP> and projects into a recess 34 which is formed in the central portion of the lower bushing 21<SP>1</SP> and is lined by a resilient ring 35 in order to limit the angle through which the floating bearing may move in any direction with respect to the fixed bearing. The floating bearing has a number of holes 40 each corresponding to one of the recesses 27 in the fixed bearing, and each communicating with a groove 39 formed on the inside of the floating bearing (see Fig. 3). Each hole 40 is provided with a nozzle 41 of which the outlet is smaller than that of the nozzles 29. The rotor is of ball-like form, and as shown in Fig. 4 consists of two hemispherical caps 49 fixed to rings 42, 43 which are clamped together against an equatorial ring 46. The outer surface of ring 46 is blackened to mark the equator of the rotor, and the two caps 49 are coloured different colours, e.g. red and blue. As shown in Fig. 7, these two colours are also marked on a circle 50 marked on the upper surface of the ring 22, which also carries a circular scale 51. Scale 51 enables the direction of flight to be read off, which the position of the horizon may be ascertained by comparing the equator marked by the black surface of the ring 46 with an index 52 marked on the outer surface of the upper bushing 21. As shown in Fig. 6, four holes 58 are symmetrically positioned on the equatorial ring 46 of the rotor and are inclined at 45 degrees to the surface, whereby the compressed air imparts rotation to the rotor. The supporting and rotor propelling air probably also causes an effect whereby the spin axis of the rotor is gradually brought into the equatorial plane of the floating bearing 30, 30<SP>1</SP>. In order to bind the floating bearing to the spin axis of the rotor, the floating bearing is provided with permanent magnets 59, Fig. 4 which are attracted by the equatorial ring 46 of the rotor, which is made of soft iron. Automatic piloting. As shown in Figs. 1 and 6, a membrane 60 is clamped between a flange 61 on the lower side of box 1 and a flange 62 on a lid 63. The spaces 65, 66 on opposite sides of the membrane 60 are fed with compressed air from the turbo-compressor through a nozzle 67 and ducts 68. 69. Space 66 is connected through ducts 70, 71 to a narrow slot 72 formed between the rings 20. Similarly, space 65 is connected by ducts 73, 74, 75 to a slot 76 diametrically opposite to slot 72. To the centre of mebrane 60 is fixed a stem 77 of a slide valve comprising a cylinder 78, and oil supply line 79, return pipes 80, and pipes 81 which connect the valve to a servomotor (not shown). Each of the slots 72, 76 co-operate with a groove 82 or 83 in the floating bearing (Fig. 4). Each of the magnets 59 has a semi-circular recess at its end, forming part of the groove 82 or the groove 83. The slots 72, 76 are of sufficient height that the function is not influenced by movement of the fixed bearing with respect to the floating bearing in the plane of Fig. 6. When, however, the casing undergoes a lateral deviation which appears as a clockwise angular movement of the casing in the plane of Fig. 4, together with the rings 20 of the fixed bearing and with the slots 72, 76, relatively to the floating bearing 30, 30<SP>1</SP> which is bound to the spin axis of the rotor, then compressed air continues to flow through the valve formed by slot 72 and groove 82 but no longer through the valve formed by slot 76 and groove 83. Compressed air thus accumulates in space 65 more than in space 66, so that the control valve of the servo-motor is operated to correct the deviation. If desired, the box with the membrane 60 may be separated from the casing 1, in which case the ducts are extended by pipes. Operation. When the electric motor 5 of the turbo-generator has been switched on, air is supplied to the rotor, which attains its normal speed of rotation after about two minutes. The hood 14 is then lowered, and a soft wood peg is moved through the opening 12 in the casing 1, through one of the openings 32 of the fixed bearing, and through an opening in the floating bearing to bear against the rotor. One of the rotor poles then moves automatically into coincidence with the peg tip. The rotor axis can thus be oriented to a required direction either on departure or during flight. Opening 12 is sufficiently large to allow the spin axis to be oriented in one direction, and the peg to be removed and reintroduced in a direction different by 90 degrees in order to slow down the rotor so that it may be brought to a stop before switching off the electric motor 5. Modifications. In the form shown in Fig. 9, the magnets which hold the floating bearing in the line with the rotor are omitted, and nozzles 86 are inserted in bores at the centre of the two hemispherical caps foming the rotor. Part of the driving air which finds itself within the rotor is expelled through these nozzles, and impinges on the diverging side walls 87a of a groove 87 provided in the vertical plane on the circumference of the interior surface of the floating bearing. In a further modification, Fig. 12, pins 90 at the centre of each cap enter a groove 187 having straight-sided walls, but which is in other respects similar to the groove 87 shown in Fig. 9.