Improvements in or relating to Apparatus for the Observation of Azimuth Angles and the Simultaneous Electrical Transmission of the Value of such Angles to Remote Indicators

100,704. Graham, E. A., and Rickets, W. J. Jan. 28, 1916. Theodolites; angle-measuring instruments.- Relates to apparatus for measuring azimuth angles and electrically transmitting their valves to a distance, and which may be used for navigation, trigonometrical work, range-finding, &c. A sighttable a, shown in plan and elevation respectively in Figs. 3 and 4, and carrying open sights b, b , is adjustably mounted on a vertical spindle c which carries a scale e and is driven through gear d, f, g, g , i, i and shafts h, from a handle m operable from any position. The shaft h operates an electrical transmitter, for example a contact drum j, and contact springs p, p , p , p co-operate in known manner to actuate distant step-by-step receivers. The handle may be frictionally connected with gear the movement of which is limited by fixed stops o. The whole apparatus is enclosed in a water-tight casing. The sights are mounted on a shaft b in a bearing a so that they may be turned down when not in use. The two positions are determined by index holes a , a with which a pin b engages. The aperture b may be adjusted for parallelism with a telescopic sight, which may be mounted in a dovetail seating a .