| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To avoid the increase of lowering speed of a boom when the load of a suspended load is heavy in a hydraulic shovel with a crane function. <P>SOLUTION: A hydraulic control circuit of a boom cylinder 8 is provided with a load detecting means for detecting the load of the suspended load; a recycling oil passage 22 for supplying a rod side oil chamber 8b with oil discharged from a head side oil chamber 8a of the boom cylinder 8 when the boom is lowered; an opening-adjustable recycling valve 23 for opening/closing the recycling oil passage 22; and a recycling valve control means 33 for making an increase/decrease adjustment of the opening quantity of the recycling valve 23 according to the load of the suspended load detected by the load detecting means during crane work. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
