| 摘要 |
PROBLEM TO BE SOLVED: To enable the lifting and lowering operation of an operation part even if trouble occurs in a power source in a tractor lifting and lowering the operation part by a solenoid valve. SOLUTION: The tractor has the operation part 3 linked to a traveling machine body 1 so as to be freely lifted and lowered, a lift cylinder 6 for lifting and lowering the operation part 3, the solenoid valve 7 for hydraulically moving the lift cylinder 6, and a controlling part 10 for electrically switching and controlling the solenoid valve 7. A lifting and lowering operation tool 20 for emergency is mechanically connected to the solenoid valve 7, and at the emergency, the solenoid valve 7 is switched and operated according to the operation of the lifting and lowering operation tool 20 for the emergency. COPYRIGHT: (C)2004,JPO
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