| 摘要 |
<p>A measuring jig surrounds a cable (8) and has a number of probe arms (10) which bear on the surface of the cable. Each probe arm has a hinged parallelogram mount (16) so that it tracks substantially parallel to the cable sheath and carries a roller (11) to reduce frictional resistance between the cable and the measuring jig. A measuring resistance wire (20) is held in tension by means of a spring (23) and is fed by way of pulleys (21, 22) to guide rollers (18), one of which is mounted on each probe arm with its axis parallel to that of the cable. The resistance wire surrounds the cable completely and electrical contact is made at two points. As the cable dia. varies during extrusion, so the length of resistance wire between the two contacts alters. The change is measured resistance provides a means of monitoring the cable diameter.</p> |
