GB562049A - Improvements in navigation-aiding course-indicating instruments - Google Patents

Abstract

562,049. Navigational instruments. POLE, J. S., GLENNY, A. P., and SPERRY GYROSCOPE CO., Ltd. Feb. 3, 1943, No. 1768. [Class 97 (ii)] In a compass repeater, the pointer, which is controlled from the controlling compass, is arranged to lie centrally on the dial and to move, when the craft turns, in the same direction to indicate the heading of the craft and the dial is also arranged whereby the relatively stationary compass card may be turned to indicate the desired set course against a fixed lubber mark, the pointer being also brought into alignment with such lubber mark. The pointer 39 is fixed on a card 38 which is cut away as shown in Fig. 1 to expose the compass card 41 having bearings marked thereon. This pointer and card 38 is arranged to follow the movements of the controlling compass by means of the repeater motor housed in the casing 7, gearing 11, 13, 21 and 23, differential gearing 25 and gears 27, 37. The bearing to be set on the compass card 41 is brought about by rotation of the compass card until the desired bearing shows against a lubber mark 57, the rotation being made by gears 51, 49, 47 and knob 55 and shaft 53. Adjustment of the pointer 39 relatively to the repeater motor is caused by operating the gears through a spring clutch, part of which comprises a spindle 73 which projects through the casing and is rotated by a key inserted in the square aperture 75. The window of the dial is provided with parallel lines 61 to facilitate detection of any movement of the pointer 39.