| 摘要 |
A probe for measuring the dimensions of a workpiece has a spherical sensing element supported on a base for three-dimensional displacement relative thereto in response to engagement between the sensing element and a workpiece. The probe comprises transducers (26) connected to a circuit (30) for determining the displacement of the sensing element in terms of the coordinate components value (X1, Y1, Z1) of the displacement. To make possible the use of the probe as a trigger probe, there is a circuit (40) for re-combining the component values thereby to determine the original displacement in terms of a resultant value (41) and a comparator (32) is provided to generate a step signal (17) when the resultant value (41) exceeds a given threshold value (r). Since the threshold value is constant, the step signal (17) occurs in response to the same displacement regardless of the direction of such displacement. |
