摘要 |
<p>Oil hydraulic pumps (3a, 3b) are connected to main pipe lines (105, 116, 107) through a delivery pipe line (102) and a feed pipe line (100). Branches (150A, 150C, 150E) are provided with flow control valves (15, 17, 19), which permit a pressure oil to flow to hydraulic oil cylinders (5a, 5b, 6, 7) from the oil hydraulic pumps (3a, 3b). A pressure oil tank (2) is connected to the main pipe lines (105, 116, 107) through a tank pipe line (103) and a discharge pipe line (101). Branches (151A, 151C, 151E) are provided with flow control valves (16, 18, 20), which permit a pressure oil to flow to the pressure oil tank (2) from the hydraulic cylinders (5a, 5b, 6, 7). A pipe line (104) branched from the delivery pipe line (102) is provided with a bypass valve (21), which serves to feed a desired amount of an oil delivered from the oil hydraulic pumps (3a, 3b) to the feed pipe line (100) and return the remainder of the oil to the pressure oil tank (2).</p> |