| 摘要 |
PURPOSE:To prevent the high-pressure storage of a bucket cylinder by a method in which the lockup of a bucket is detected, and a low-pressure overload valve of the high-pressure and low-pressure overload valves provided on the rod side of the bucket cylinder is operated. CONSTITUTION:When oil pressures are supplied to the rod side of a bucket cylinder 12 for loading soil scooped up by a bucket 5 and the bucket 5 is dumped toward the direction of arrow (a), a solenoid valve 21 is turned on by a detector 19 just before a tilt link 7 comes into contact with a dump stopper 18. Oil pressures controlled by a low-pressure overload valve 20 are supplied to the rod side of the bucket cylinder 12, and thereby the storage of great oil pressures in the rod side of the bucket cylinder 12 after lockup is prevented. Shock to be encountered during the tilting of the bucket can be greatly reduced, and the droppage of the speed of lockup can also be lessened. |
