Patent GB-137060-A (GB)
Title: Improvements in or relating to angular velocity indicating apparatus
IPC: G01C19/02
Filed: 1919-12-24
Abstract: 137,060. Minorsky, N. Dec. 26, 1918, [Convention date]. Indicators, speed. - Gyroscopic apparatus for indicating the angular velocity of a body about a definite axis, for example the velocity of yawing of a ship, is provided with means whereby the indicator is not affected by forces due to movements of the body about an axis or axes at an angle to the first-mentioned axis. The apparatus shown in Figs. 1 and 3 comprises two equal gyroscopes adapted to be rotated in opposite directions around the axis III-III within casings 12, 13 pivoted on horizontal axes 16, 17 in standards 18, 19 secured to a base 20. Mounted centrally between the gyro-casings are two closed chambers 21, 22 having flexible walls 23, 24 the centres of which are connected by adjustable links 37, 38 to levers 26, 27 mounted on fixed horizontal shafts 30, 31, the levers being connected to lugs 34, 35 on the gyro-casings by links 32, 33. The chambers 21, 22 are filled with oil and are respectively connected by pipes 45, 47, Fig. 4, to the ends of a cylinder 46 also filled with oil and containing a piston 48 from each side of which projects a rod 49. Centralizing springs 50 are mounted on the rod 49 between collars 51 and adjustable bushes 52. When the apparatus is turned round the axis I-I, the casings 12, 13 will precess in opposite directions and hence one of the chambers 21, 22 will be compressed and the other extended, and in order to indicate electrically the resulting movement of the piston 48 the rod 49 carries a rod 67 having a fork 68 in which is mounted a roller 69 of conducting material bearing on an internally-threaded block 70 having two conducting segments 74, 75 separated by an insulating strip 76. The segments 74, 75 are respectively connected to opposed fieldwindings 64, 65 of a motor 60 which rotates the threaded shaft 61 passing through the block 70. The rotation of the shaft 61 is thus proportional to the movement of the body 48; to indicate the angular velocity of the body on which the apparatus is mounted, a transmitting switch mounted on the shaft 61 controls a step-by-step motor adapted to actuate a pointer. When the body turns around the axis II-II, the casings 12, 13 tilt in the same direction and no movement of the piston 48 results. In order to neutralize the torque due to simultaneous turning around the axes II-II and III-III, two similar motors 90, 91 are provided with their rotors secured to the axles 16, 17 respectively, the stators being fixed. The circuits of these motors are arranged so that the rotor currents, for example, are proportional to the tilts of the gyro-casings while the stator currents are proportional to the velocity of the apparatus around the axis, III-III; the arrangement shown in Fig. 5 for this purpose comprises three rheostats 100, 101, 102 of which 100, 101 are respectively connected in the circuits of the rotors 92, 96 while rheostat 102 is connected in the stator circuits 94, 98. The arms 103, 104 are controlled by the shafts 30, 31 so as to adjust the resistances in the rotor circuits while the arm 129 is controlled by the precession of an auxiliary gyroscope 117 responsive to torques around the axis III-III. The rheostats may also have additional contact segments 138, 139 adapted when both arms 103, 104 are in their central positions, to complete the circuit of an electro-magnet 134 and thus, by means of a bell-crank lever 132, to turn a spindle 56 and open a valve 55, Fig. 4, to allow communication between the pipes 45, 47 in order that the piston 48 may be readily centralised. In a modification, the relative movements of the gyro-casings 12, 13 are indicated by a differential gear device, the casings being, in this case, centralized by springs. The apparatus may be used in connexion with steering-devices of the kind described in Specification 127,356, [Class 114, Ships &c., Propelling &c.].