| 摘要 |
A stylus support carries a stylus 14 having a stylus tip 14a for following a workpiece surface which rotates relative to the stylus support 300. A transducer senses a displacement of the stylus tip as follows the surface. A support structure (24, fig.1) includes a mounting arm 200 and an attitude arm 100 carrying the stylus support and mounted to the mounting arm 200 by a kinematic coupling (figs 3 and 4) so as to be moveable between the first attitude in which a stylus extends in a first direction and a second attitude in which the stylus extends in a direction transverse to the first, the movement being substantially centred at the stylus tip. Different aspects of the invention have been specified in four independent claims. A first aspect defines a biasing mechanism for biasing the attitude arm into the first attitude when the attitude arm is moved towards the first attitude and for biasing the attitude arm into the second attitude when the attitude arm is moved towards the second attitude. Another aspect specifies the coupling comprising protrusions (104) and recesses (204) provided on opposing faces of the attitude and mounting arms, the protrusions and recesses being configured to cooperate to constrain relative motion of the opposing faces when the attitude arm is moved into one of the first and second attitudes. |
