| 摘要 |
<p>PURPOSE:To enable the quick operation of a hydraulic cylinder by connecting a pilot pipe line for a logic valve to the pilot port of the logic valve through a sequence valve. CONSTITUTION:A confluence pipe line 33 equipped with a logic valve 32 is interposed between a contraction action pipe line 8 at the side of a cylinder 1 from a sequence valve 30 and a check valve 31, and an extension action pipe line 7 at the side of an operation valve 4 from a boosting circuit 12 and a low pressure circuit 14. When the hydraulic cylinder 1 is extended, if hydraulic pressure is less than the set pressure of the sequence valve 30 in a pilot pipe line 37 for a logic valve at the time of low loading, pressure oil discharged out of a hydraulic pump 5 is fed to the head side oil chamber 2 of the hydraulic cylinder from the low pressure circuit 14 through the operation valve 4 and a pilot check valve. Since the rod side oil chamber 3 of the hydraulic cylinder 1 is simultaneously communicated with the low pressure circuit 14 through the logic valve 32, the confluence pipe line 33, and operating oil flowing out of the rod side oil chamber 3 of the hydraulic cylinder 1 is also fed to the head side oil chamber 2, so that the hydraulic cylinder 1 is thereby quickly extended.</p> |
