GB133047A - Improved Mariners' Liquid Compass. - Google Patents

Abstract

133,047. Boccardo, G. Jan. 29, 1915, [Convention date]. Mariners' compasses, of the liquid type are provided with a chamber 9 at the central part of the cover glass 4 within which variation of the level of the liquid due to its expansion may take place, a scale 11 is provided on the inner surface of the wall of the bowl at its upper part, and the inner surface of the wall of the bowl is conical at its lower part. As shown, the chamber 9 is screwed on to a hub 8 communicating with the interior of the bowl, and has screws 10 which may be removed to permit filling of the bowl, the screws having capillary axial holes to permit the passage of air. The cover glass is secured by means of a ring 2 and packing 3, and a bottom glass 7 is similarly secured. The card 17 carrying magnets 15 is mounted on a pivot 13 secured to a three-armed frame 12 bearing against the conical wall. A rotatable ring 18 carries posts 19, 20 diametrically arranged, the post 19 having a sighting thread 25 and a slide 21 hingedly carrying a frame 21<1> containing sighting mirrors, and the post 20 having a slide 22 provided with a sighting aperture 23 and dark glasses 24. A lenticular prism 26 having a sighting line is pivoted on a horizontal axis at the bottom of the post 19. The bowl is mounted by means of knife edges 27 on a gimbal ring 28, and carries an annular weight 30.