GB716871A - Improvements in or relating to movement-damping devices for gyroscopic instruments - Google Patents

Abstract

716,871. Gyroscopic apparatus. REID, G. H. Aug. 11, 1952 [May 11, 1951], No. 11223/51. Class 97(3) A gyroscopic apparatus includes a gyro-rotor in a pivoted gimbal frame, a spring operatively connected to the gimbal frame to restrain pivotal movements thereof and an eddy current device for damping oscillatory movement of the gimbal frame and spring, this device comprising a fixed element, and a movable element connected to the gimbal frame, one element being a magnet and the other being a body of electrical conducting material disposed in the field of the magnet. As applied to a rate of turn indicator, the gimbal 10 of which is urged towards its normal position by a spring 9 and is connected by gears 16, 17, to an indicating pointer 19, the eddy current device comprises a metallic rotor 43 carried by a spindle 40 connected to the gimbal by movement multiplying gearing 47-51 and a permanent magnet 32. The magnet is mounted on a spigot 31 in which the spindle 40 is freely rotatable. This spigot is carried by the end wall 30 of a cup-shaped member 21 having a flange 27 of magnetically-permeable material, engaged by a screw 28 passing through a helical slot in a member 22 secured to a fixed base plate 23. The induced magnetism resulting from the eddy currents formed in rotor 43 reacts with the field of magnet 32 to brake the rotor and thus damp out oscillations of the gimbal 10 so that pointer 19 gives a steady indication. The braking effort may be increased by rotating member 21 so that the magnet 32 is moved further into the rotor 43.