| 摘要 |
<p>PROBLEM TO BE SOLVED: To interlock a hydraulic cylinder for a boom telescopic motion with a hydraulic motor for a winch by an operation of a directional control valve to make a hook suspending length kept substantially constant. SOLUTION: In a crane provided with a boom for conducting a telescopic operation by the hydraulic cylinder 8 for the telescopic motion of the boom, and the winch for winding a hook up and lowering it by the hydraulic motor 10 for the winch, a directional control valve 30 for interlock for communicating the hydraulic motor 10 with a contracted side oil chamber 26 of the hydraulic cylinder 8 via an interlocking pipeline 31 and for communicating an expannded side oil chamber 33 of the cylinder 8 with a lowering side port A of the directional valve 16 for the winch via an interlocking pipeline 32 is provided in a midway of a lowering pipeline 28 for connecting the hydraulic motor 10 with the lowering side port A of the directional control valve 16.</p> |
