| 摘要 |
<p>The pulley support is mounted on the end of a jib. There are locking parts (60,61,62) for holding a lever (37) relative to the support (4) in at least one position. The lever is raised in the jib lifting or horizontal position. The lock consists of a pin (62) fitting in holes (61,60) in the lever (37) and support (4), which are aligned in the locking position. When the pin (62) does not lock it fits into rest holes (63) in a neutral part of the support. The pin is remote controlled by e.g. an electromagnet or ram.</p> |
