Traveller position and alignment error determination appts.

摘要

The apparatus for determining the position and alignment of a moving traveller-head (5) w.r.t. a fixed guide path and scale (7) employs a stationary fixture (1) containing a laser source (2).The laser beam (4) enters a semi-reflecting (13) beam splitter (8), and its direct component is registered by a sensor while its reflected component (12) is turned through 180 deg. by a pentaprism (9) to impinge on a detector surface (3).The angle of tilt (alpha) of the traveller head (5) w.r.t. the X axis of Cartesian coordinates (X,Y,Z) is determined by the distances (Dz) and angular deviations of the traveller (5) w.r.t. the Y and Z axes are registered.