Patent ID: 8537372

Claim:
A coordinate measuring machine for determination of at least one spatial coordinate of a measurement point on an object to be measured, comprising: a base; a probe head for approaching the measurement point, a frame structure for linking the probe head to the base, the frame structure including: at least a first and a second frame component; and at least one linear drive mechanism moveably linking the first and the second frame components, for provision of movability of the probe head relative to the base in a first direction, wherein the at least one linear drive mechanism comprises: a linear guide in the first direction; a movable member being supported for movement along the guide by bearings; and a linear measuring instrument for determination of a first drive position of the movable member in the first direction, wherein: at least a first optical reference element designed as an optical reference beam for providing a first reference path, wherein the reference beam extends along the guide of the linear drive mechanism so that the reference path is parallel to the first direction; and at least a first and a second displacement sensor are assigned to the reference beam, the reference beam and the displacement sensors being designed and arranged in such a way, that two or more distances from defined positions on the movable member to the reference beam and/or impinging positions of the reference beam are measurable by the displacement sensors, wherein the distances respectively impinging positions indicate translational and rotational displacements of the movable member from the ordinary bearing position, wherein at least the first displacement sensor being built so as to partly transmit the optical reference beam and at least the second displacement sensor being assigned to a transmitted part of the optical reference beam and the displacement sensors being built as photosensitive detector elements being built for measuring distances to the reference beam and/or an impinging position of the reference beam indicative of the displacement of the movable member relative to the first reference path in a direction perpendicular to the first direction.