| 摘要 |
PURPOSE:To reduce a tilt-up time while prevent the breakage of a time cylinder by connecting the feeding pipe line on the lower chamber side of a trim cylinder to the feeding pipe line of oil pressure generated by a hydraulic pump to a tilt cylinder via a selector valve with a relief valve. CONSTITUTION:A pressure oil generated by a normally/reversely rotatable hydraulic pump 30 is fed to a tilt cylinder 10 via the check valves 35a, 35b of an opening/closing device 33 and pipe lines 37a, 37b to carry out a tilt-up operation. A selector valve 44 with a relief valve 46 is provided midway in the pipe line 37a to the lower chamber B on the tilt-up side of the tilt cylinder 10 to connect the pipe line 37a to the lower chamber D of a trim cylinder 20 via a pipe line 38a. At the time of tilting up, since the pressure oil in the pipe line 37a is not fed to the trim cylinder 20 side, the tilting up can be carried out in a short time while, at the time of tilting down, when the lower chamber D of the trim cylinder becomes high pressure, the pressure is discharged through the relief valve 46 preventing its breakage. |
