Surveying instrument scales homologas 3 sizes, multangular, vertical and horizontal

摘要

A hemi-spherical member (4) is marked with lines of latitude (41) and longitude (42) and a triangular tip (431) is disposed at the top of the member to provide a reference point. A plumb bob (46) is mounted by a threaded hole (461) to a rod (442) disposed centrally of an axially-disposed sleeve (44). A rod (45) which passes through the sleeve is formed at either end with pyramidal tips (451,451') for engagement with concave internal surfaces (as 51) of a two-part spheroidal shell (5,5'). Holes (52,52') in the surface of the spheroidal shell are engaged by tips (541) of racks (54) which are L-shaped and engage in a respective hole (62,62') in the base member (6). The axes of the racks are aligned along a Z-axis of a three axis system of which the rod supporting the plumb bob (46) defines the Yaxis and the axial rod (442) defines the X axis. The latitude and longitude scales on the spheroidal scales represent the angles in three dimensional space. (Provisional basic advised week 88/49).