Patent ID: 7024273

Claim:
A probe driving mechanism for displacement measuring apparatuses for use in measuring the sizes of a workpiece without causing the workpiece to be deformed even when a probe is brought into contact therewith, comprising: a motor for driving the probe; a scale for detecting the displacement of the probe; a workpiece sensor for detecting the engagement of the probe with the workpiece; and a device for: controlling a power being applied to the motor based on an output from the scale when the output from the scale varies based on the power applied to the motor; making a judgment that the probe contacts the workpiece when the output from the scale becomes less than a level of power being applied to the motor, and then reducing the power being applied to the motor; and subsequently controlling the power being applied to the motor based on a greater one of speed variation of the output from the scale and an output from the workpiece sensor when the output from the workpiece sensor varies.