Precision pointing instrument with angle bracket - carries graduated scale and mobile arm with second scale, window and cursor

摘要

The precision pointing instrument comprises an angle bracket, (1, 2) one side (2) of which carries a first ruler (4) graduated longitudinally. A mobile arm (3), fitted with a second ruler (5) also graduated longitudinally, may be moved along the side of the angle bracket (2) which carries the first graduated ruler, while remaining parallel to the other side of the angle bracket. The mobile arm (3) has a window (32) at its extreme end against the angle bracket and the graduation of the first ruler appears through this window. The second ruler has a cursor (7).