| 摘要 |
PROBLEM TO BE SOLVED: To provide a grapple device of a construction machine enhanced in durability and stabilized in operation by preventing a hydraulic cylinder for operating grapple arms from being overheated. SOLUTION: The grapple device comprises a plurality of the grapple arms 6, 7 so rotatably attached to the end of a boom 4 as to be opposed to each other. A hydraulic cylinder 15 for rotating the grapple arms 6, 7 in the holding direction during extension and rotating the grapple arms 6, 7 in the opening direction during retraction is provided. A bypass oil path 29 allowing a first oil path 25 for extending the hydraulic cylinder 15 to communicate with a second oil path 26 for retracting the hydraulic cylinder 15 is formed near the hydraulic cylinder 15. A relief valve 30 is installed in the bypass oil path 29. The relief valve 30 makes hydraulic oil flow from the second oil path 26 to the first oil path 25 when the pressure of the hydraulic oil supplied into the second oil path 26 reaches a predetermined value. COPYRIGHT: (C)2009,JPO&INPIT
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