| 摘要 |
A wire or cable is provided internally of an extensible boom to connect a switch, control or other element, such as an anti-two block switch, at one end of the extensible boom to elements or controls at the other end, such as controls for operating the crane. The wire or cable is itself inextensible, and is normally maintained taut. Wire control elements are provided to permit movement of the wire to accommodate extension and retraction of the telescopic boom sections. The wire internal to the extensible boom is fully protected from the environment and external hazards.
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