Patent GB-135500-A (GB)
IPC: G01C19/38
Abstract: 135,500. Sperry Gyroscope Co., (Assignees of Tanner, H. L.). Nov. 19, 1918, [Convention date]. Gyroscopic compasses.-The gyroscope is so arranged as to be practically unaffected by shortperiod oscillations such as rolling or pitching, but is adapted, upon the occurrence of long period oscillations, such as its precessional oscillation about the horizontal axis, to be subjected to a torque around the horizontal axis, the torque being set up by automatically-operating means carried by the gyroscope casing. In the form shown in Figs. 1 and 2, the gyroscope rotor 27 rotates, in a direction opposite to the horizontal component of the earth's rotation, on the horizontal axis 26 in the casing 25 pivoted at 23, 24 in the member 22 carrying the vertical spindle 16, the casing being substantially balanced, but preferably slightly pendulous, about the axis 23, 24. Symmetrically disposed on the lower part of the casing are two vessels 31, 32 containing mercury &c. and connected by a fine-bore tube 33. When the gyroscope precesses about the axis 23, 24, a torque is set up due to the flow of mercury along the tube 33, but the bore of the tube is so fine that practically no mercury flows when the gyroscope is subjected to short-period oscillations. In the form shown in Fig. 6, the casing 25 is pivoted on an horizontal axis 50 in a ring 48, which is pivoted on an horizontal axis 24 in the ring 22<1>. The casing is connected to the ring 48 by a slowly-yielding device such as a dash-pot, the case 51 of which is carried by the casing 25 while the plunger 52 is connected to the ring 48. The ring 48 and casing 25 may also be connected by centralizing-means comprising springs 54, 55 secured one to each side of the casing, and both secured to an arm 56 depending from the ring. Stops 59, 60 are provided for limiting the inclination of the casing 25. In the further modification shown in Fig. 8, the slowlyyielding connexion between the casing 25 and ring 48 comprises cylinders 61, 62 secured to the casing and containing pistons 63, the rods 64, 45 of which are connected to the ring 48. Passing into the lower ends of the cylinders are pipes 66, 67 connected to a reservoir 36, which may be arranged as in the damping-means described below. Also secured to opposite sides of the casing are receptacles 68, 69 containing oil &c. and connected by a tube 70. In this construction, the gyroscope rotates in the same direction as the earth. Means for damping the oscillations of the gyroscope comprise a reservoir 36, Fig. 3, communicating with the interior of the casing 25 by a passage 35, the ends of the reservoir being crossconnected by pipes 37, 38 to receptacles 39, 40 secured to the casing. These receptacles communicate by pipes 41 having restricted passages 41<1> to the bearings 29, 30. The reservoir 36 and receptacles 39, 40 contain oil which can be observed through windows 40<1>. The rotor 27 is provided with ducts 43, through which the oil can pass under the action of centrifugal force. Owing to the cross-connexion of the pipes 37, 38, a larger quantity of oil passes to the receptacle on the high side of the casing when the latter becomes tilted, and hence a damping effect in produced. In the modification shown in Fig. 5, the pipes 37<1>, 38<1> are not cross-connected, and the reservoir 36' contains a number of balls 46 adapted to close the outlet to the receptacle on the low side of the casing when a tilt occurs.