| 摘要 |
Two dimensional measuring apparatus includes a surface 15 on which an object to be measured can be placed and under which is an optical grating 16 comprising two sets of parallel lines perpendicular to axes at a known angle to each other, usually 90 DEG . A base 10 movable relative to surface 15 in a plane containing the directions of the axes carries probe 18 and support 19, bearing two reading heads 21, 22 each having a source, detector and an index grating with lines 23 or 24 cooperating with grating 16 to derive electrical signals indicative of movement of an index point, which is in the plane of lines 23, 24 and on the axis of probe 18. Support 13 is moveable relative to rails 11 on base 10, by wheels 12 and by sliding along their axles. <IMAGE> |
