| 摘要 |
PROBLEM TO BE SOLVED: To increase energy-saving effect in a hydraulic elevator using a piston type hydraulic cylinder. SOLUTION: A balance weight 7 provided at the upper end part of a piston rod 2 is to have weight obtained by adding a half of fully laden weight to the weight of a car 15. At the time of moving up the car 15, pressurized hydraulic oil is fed to a cylinder tube inner chamber 2a on the piston rod 2 side, and hydraulic oil in a cylinder tube inner chamber 3a on the piston lower side is discharged to an operating oil tank 21. At the time of moving down the car 15, the pressurized hydraulic oil is communicated with the cylinder tube inner chamber on the piston lower side. A lowering solenoid valve 42 is made a D-circuit. Return hydraulic oil from the cylinder tube inner chamber therefore joins the pressurized hydraulic oil from a hydraulic pump via the lowering solenoid valve 42 and a check valve 43 so as to keep a balance of ascending/ descending speed of the car 15. |
