GB664760A - Improvements in or relating to range finding surveying instruments - Google Patents

Abstract

664,760. Position finders; surveying instruments. SVENSKA AKTIEBOLAGET GASACCUMULATOR. Feb. 15, 1949 [Feb. 23, 1948], No. 4121/49. Classes 97 (i) and 97 (ii). A surveying instrument wherein a rangefinder and a plotting device are coupled for rotation about a common vertical axis for sighting on an object and are also operated by mechanism whereby movement of a plotting point radially of said axis is effected simultaneously with and in proportion to adjustment of the range-finder is characterized in that the mechanism for operating the range-finder is coupled to the mechanism for adjusting the plotting point by a coupling member which, when rotated about said axis, is adapted to effect radial movement of said plotting point. The instrument shown comprises a distant base range-finder consisting of two telescopes 3, 4 coupled by a sleeve 12 with a plating device K, the sleeve 12 being rotatable about a vertical axis in bearings H supported by a member S. The plotting device K comprises a plotting point 8 carried by a ruler 7, which is attached to the lower end 10 of sleeve 12. and supports a rack 6, which meshes with a pinion 18 on a shaft 16, coaxial with the sleeve 12 and engaged at 19, 20 with a rod 21 which is manually operable at 1. Rotation of rod 21 causes vertical displacement of a slider S<SP>1</SP> along a threaded rod 5 geared to the shaft, and this slider causes rocking of a rod 24 and consequent elevation of the telescope 4. In use, the range-finder housing 13 is rotated to bring the desired object into view, such rotation causing rotation of ruler 7. Thereafter, shaft 21 is rotated until the telescope 4 is sighted on a mask at a known height above the axis of telescope 3, rotation of this shaft causing proportional radial displacement of the plotting point 8. The latter can thus indicate on a chart the position of the object sighted relative to a fixed point 14.