| 摘要 |
<p>In a co-ordinate measuring machine a base structure (10) supports guideways and carriages providing for movement of a probe adapted to contact a workpiece, and a separate structure (20) is provided for supporting the workpiece itself. The structure (20) can be supported directly on a foundation (16) by an arrangement of bars (54) capable of restraining all six degrees of freedom of movement of the structure (20), i.e. straight line movement in each of the X, Y and Z directions and rotation about each of the X, Y and Z axes. Each bar (54) is stiffened in the direction of its own axis but enables compliance in all directions normal to this axis to accommodate small movements of the structure (20) without stress or strain. The base structure (10) is mounted on the workpiece structure (20) by a similar arrangement of the bars (54) which thereby restrain all 6° of freedom of movement of the base structure (10). There is thereby avoided relative movement between the base structure (10) and the workpiece structure (20) which would otherwise result in loss of measurement accuracy to an extent significant in high accuracy measuring and checking machines.</p> |
