Patent GB-455514-A (GB)
Title: Improvements in or relating to gyroscopic apparatus
IPC: G01C19/42
Filed: 1935-06-04
Abstract: 455,514. Gyroscopic apparatus. BARNES, J. W., Royal Aircraft Establishment, South Farnborough, Hampshire. June 4, 1935, No. 16095. [Class 97 (iii)] An instrument for indicating either the amount or rate of turn according to the operation of selective mechanism comprises a single gyroscope and a single pointer carried by the gimbal ring carrying the rotor. The pointer indicates the amount or rate of turn in relation to a datum or scale on the instrument casing and the outer gimbal ring is automatically centralized by means controlled by the selective mechanism. In the form shown in Fig. 1, the rotor 1 is mounted with horizontal fore-and-aft spin axis 2 in a gimbal 3, pivoting on a horizontal transverse axis 4 in a vertical gimbal 5. The latter is pivoted on a vertical axis 6 in the instrument casing 7. The pointer 8 comprises a leaf spring attached at one end to the gimbal 3 with its plane at 45‹ to the vertical and provided at the other end with a rod-like extension 9 carrying a roller 10. When the gyro is free the pointer 8 remains straight and indicates pitch and turn with reference to cross lines on the glass window 11. To cause the gyro to indicate rate of turn, upper and lower cranked levers 14, 19, pivoted at 15, 20, respectively, and interconnected by pins and slots 16, are moved by a crank handle 25 connected to the lower lever 19 by a pin 22 and slot 21, and cause cam surfaces 27 to lock the gimbal 5 about the vertical axis 6 and guide plates 13, 17, to restrict the movement of the outer end of the pointer 8 to a horizontal direction. During turning of the craft the gyro precesses on the pivots 4 and bends the spring 8 which, because of the inclination of its plane to the vertical gives rise to proportional horizontal movement of the end 9, thus indicating the rate of turn. In the modification shown in Fig. 4, the rotor 31 spins on a transverse axis in a gimbal 32 pivoting on a fore-andaft axis 33 in a vertical ring 34 which in turn pivots on a vertical axis 35 in the casing 36. By pushing in a knurled knob 42 a roller 45 first engages a heart-shaped cam 41 on the gimbal 34 centralizing the latter and then passes into a slot where it engages and moves to the left a bent strip of metal 47 guided on the gimbal 34 by two screws. The strip 47 engages one arm of a bell-crank lever 48 pivoted on the gimbal 34 at 49. The other arm of the bell-crank lever 48 is pivoted to a link 50 which has its upper end bent and slotted to engage a leaf spring 51. The latter is carried by a bracket 52 fixed to the inner gimbal 32 and is broadened at the lower end to form a pointer visible through the narrow window 53. When the knob 42 is in the outer position, the link 50 engages the spring 51 at a point in line with the axis 33 and the spring 51 moves with the gimbal 34 without bending thus indicating amount of turn at the window 53. When the knob 42 is in the inner position, the gimbal 34 is centralized and locked and the link 50 engages the spring 51 above the axis 33 so that during turning of the craft the gyro precesses on the axis 33 and bends the spring 51, the free end of which then indicates rate of turn at the window 53. By turning the knob 42 when in the inner position a cylindrical scale 37 in frictional engagement with the gimbal 34 may be adjusted relatively to the latter.