| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic cylinder device for a grab bucket suitably extendable and retractable even if air is mixed in a cylinder and having high safety. SOLUTION: This hydraulic cylinder device for the grab bucket is used for a grab bucket and formed of the hydraulic cylinder 6 and a hydraulic cylinder control means. The hydraulic cylinder 6 comprises a cylinder body 9, a piston 10 reciprocatingly inserted into the cylinder body 9, and a piston rod 11 fixed to the piston 10 and led to the upper end of the cylinder body 9 so as to be extended and retracted. The hydraulic cylinder control means comprises a hydraulic pressure control flow passage 30 allowing an upper side hydraulic chamber 9a to communicate with a lower side hydraulic chamber 9b and a selector valve 33 capable of changing over the flow passage 30 between a state in which oil flows from the upper side hydraulic pressure chamber to the lower side hydraulic pressure chamber and a state in which the oil does not flow. An oil tank 31 is installed in the hydraulic pressure control flow passage 30. COPYRIGHT: (C)2006,JPO&NCIPI
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