| 摘要 |
An improved link arm assembly which couples a surface finish measuring instrument housing to an associated probe which is moved across a workpiece surface to evaluate surface finish characteristics. The link arm assembly enables a probe mounting arm to be rotated from an inoperative, generally vertical position to a rotated generally horizontal operating position in which the probe is positioned in contact with a workpiece surface. In accordance with the present invention, a clutching arrangement is provided which enables the probe mounting arm to be rotated freely from the operating to the normal position but which imposes fluid damping in the opposite direction of rotation which limits the angular velocity of the probe mounting arm and the impact forces which are imposed on the probe when it is being moved into contact with the workpiece. Accordingly, damaging high impact between the probe and workpiece is avoided.
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