| 摘要 |
PURPOSE:To prevent the floating of vehicular body by a method in which the head pressure of boom cylinder and the position of bucket are detected, and when load beyond a set value occurs, the operating oil of head is relieved. CONSTITUTION:The oil pressure of the head 71 of a boom cylinder 7 is transmitted through a return oil path 8 and a pressure switch 9. The position of a bucket is calculated in a controller 4 from angles detected by a boom angle sensor 3A and an arm angle sensor 6. In the controller 4, in case the head pressure of the boom cylinder is overloaded, a solenoid valve 10 provided for the return oil path of the boom cylinder is opened to allow excess oil pressure to escape to a tank 12. The controller 4 is also connected to an excavation mode switch 13 to switch overload to light, medium, or heavy. The floating of the front wheel can thus be prevented. |
