| 摘要 |
PURPOSE:To improve the descending accuracy of a ram by connecting the switching valve of a press oil as well as providing a quantitative cylinder at the rod side of a lifting cylinder and arranging a return device to the floating piston in the quantitative cylinder. CONSTITUTION:A quantitative cylinder 5 is provided on the rod side piping 6 of a lifting cylinder 2, a switching valve 8 is connected to as well and a return device 9 is arranged for the floating piston 7 inside the quantitative cylinder 5 as well. When the switching valve 8 is made at descent position and the press oil of the rod side of the cylinder 2 is fed to the head side of the quantitative cylinder 5 first, the floating piston 7 is retreated and a ram 1 is descended by the oil amt. thereof. When the valve 8 is then made at return position, the piston 7 is advanced and the pressure oil in the same amt. is returned, so the ram 1 is descended by the same amt. again. The effect of the fluctuation in the pressure and temp. is eliminated and the descending accuracy of the ram 1 is improved.
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