Telescoping of the boom is carried out through telescoping cylinder and steel cable, and all booms telescope simultaneously.
吊臂的伸缩是通过伸缩油缸和钢丝绳进行，各伸缩臂同步伸缩。
2
An apparatus used for hoisting weights, consisting of a vertical spool-shaped cylinder that is rotated manually or by machine and around which a cable is wound.