GB957163A - Improvements relating to apparatus for testing gyroscopes - Google Patents

Abstract

957,163. Gyroscopic apparatus. GRASEBY INSTRUMENTS Ltd. May 26, 1960 [Feb. 27, 1959], No. 7040/59. Heading G1C. Gyroscope testing apparatus comprises a gimbal ring 34, Fig. 1, adapted to, receive the gyroscope to be tested, the gimbal 34 being pivoted by stub shafts and ball or roller bearings 33, Fig. 2, within a cage 23 which is itself pivoted by trunnions 21, 22, in bearings 20 on a pair of pillars 18, 19 rising from a table 12. The table 12 may rotate, as shown, about a vertical pivot pin 13, or, in a modification, the trunnions 21, 22, are pivoted in bearing in a yoke which is rotated about an axis parallel to the earth's axis at the rate of one complete revolution per siderial day in the opposite direction to that of the earth to eliminate the effect of the earth's rotation. Fine adjustment devices are provided for rotation about the various axes, means such as 62 being provided to allow them to be disengaged. Circular scales 15, 24 are read by microscopes 16,25 respectively whilst scale 36 is associated with light source 41, half silvered prism 38, double prism 39 and microscope 37 for direct reading, and light source 41, prisms 38,39,42,43, 44, objectives 45, 46 and photo-electric cell 40 for automatically reading or recording the angular position of gimbal 34 with respect to cage 23. The graduations on scale 36 may be formed as transparent markings on an opaque background and the photo-cell 40 provides a signal, such as at each minute of arc movement, when the image of the transparent marking on one side of the circle coincides with a transparent mark on the diametrically opposite side. Instead of the gimbal 34 being rotated by hand a servomotor mounted on end plate 29 of cage 23 may drive the rim of a disc 56 mounted on the upper end of the gimbal 34. Various tests which can be made on a gyroscope and the associated electrical circuits are described in the Specification.