| 摘要 |
<p>An article handling structure includes an arrangement for monitoring the orientation of the second end (58) of a link arm (50) with respect to the first end (42) of the link arm. A light beam source (45) is mounted on the first link end and is adapted to direct at least one light beam along said link arm to a predetermined position on said second end and a light beam detector (55) mounted on said second end is adapted to produce a signal representative of orientation of the second end with respect to the first end responsive to said light beam.</p> |
