| 摘要 |
<p>PURPOSE:To prevent the occurrence of hunting without regulation to loader speeds by a method in which higher pressure from among the pressure of return oil-side pipeline of an oil-pressure cylinder for driving the loader and the pressure of the supply oil-side pipeline is supplied as a pilot pressure to a counter- balance valve. CONSTITUTION:A direction switching valve 11 is provided between a burr cylinder 5 and an oil-pressure pump 10 to supply the pressure oil of the burr cylinder 5. A counterbalance valve 15 and a check valve 16 are provided in parallel to a pipeline 14 to form a return oil side when the cylinder 5 is contracted. A shuttle valve 31 is provided between a pipeline 18 to form a supply oil side when the cylinder 5 is contracted and the pipeline. Higher pressure of the pressures of the pipelines 14 and 18 is supplied as a pilot pressure to the valve 15. When the cylinder 5 is contracted, the back pressure of the pipeline 20 can thus be directed through the valve 31 to the valve 15.</p> |
