GB322497A - - Google Patents

Abstract

322,497. Brown, S. G. Sept. 6, 1928. Mariners' compasses.-In apparatus for sighting moving objects, such as sighting telescopes for gunnery' control apparatus, in which it is desired to take a reading of a compass card, means are provided whereby a reading member may be caused to rotate with the sighting device or to be detached therefrom at any moment so that an accurate reading may be taken without interrupting the sighting of the moving object. A sighting telescope 1 carried on the support 3 has a pivot rotating in a sleeve 5 which itself is free to rotate in an outer sleeve 6 on a plate 7. Attached to the sleeve 5 is a disc 8 constituting the compass-card, actuated by the motor 9 from a master compass. Resting on the disc 8 is a ring 19 to which is clamped by rings 20, 21 a spinning 22 extending over the edge of the compass card and carrying a reading member 23. A bracket 25, rigidly attached to the support 3 carries a spring controlled plunger 26 co-operating with a socket 30 on the spinning 22 so that when depressed the plunger 26 ensures that the spinning 22 rotates with the telescope 1, but when released by depressing the trigger 34 the spinning 22 remains stationary, enabling a reading of the compass card to be taken. A mirror 40 may be fitted as shown for taking bearings from the stars and the whole apparatus is mounted in gimbals. Alternatively the connection between the reading member and the telescope may be by an electromagnet rotating with the telescope.