| 摘要 |
PROBLEM TO BE SOLVED: To make one hose serve the purpose of the two hoses of pressure-oil supply and pressure-oil return holes for supplying and discharging pressure oil to and from a hydraulic cylinder for compensating the jacking direction. SOLUTION: In the buried-pipe jacking-direction compensator, in which a cutting edge is connected in a freely oscillating manner by at least three compensation hydraulic cylinders, one pressure-oil supply-combining return hose 9 joined with a hydraulic-source unit comprising an oil tank 7, a hydraulic pump 8 or the like installed on the outside of a buried pipe is passed into the buried pipe and extended up to compensation hydraulic cylinders while the supply of pressure oil is conjoined with valves 15, 16 for changing over the expansion and contraction of each compensation hydraulic cylinder and each compensation hydraulic cylinder 22a-22b through valves for selecting driving, and an accumulator 30 receiving pressure oil pushed out from another section when pressure oil is fed is mounted while pressure oil accumulated in the accumulator 30 is returned to the oil tank 7 through the pressure-oil supply-combining return hose 9 when the expansion-contraction driving of each compensation hydraulic cylinder is stopped. |
