| 摘要 |
<p>The device comprises three arms (10,20,30) which are cyclically coupled to each other by means of slots (12,22,32) and/or bars (16,26,36). The arms can be displaced relative to each other, maintaining an angle of approximately 60 degrees. One or more measuring wheels or rollers are arranged at the end of an arm for contacting the surface of a hollow cylinder to be measured. A light transmitter may be provided.</p> |
