| 摘要 |
PURPOSE:To make a pump of large-capacity discharge unnecessary, by a method wherein hydraulic cylinders are divided into groups Y, Z so that anti-piston rod side oil chamber of the group Y communicates with a tank during a compression process and hydraulic oil discharged through an anti-piston rod side chamber of the group Z is sent into a piston rod side oil chamber of the group Y by performing confluence. CONSTITUTION:Hydraulic cylinders 2, 2 of H and J are made a group Y and I and K are made a group Z. Since discharge oil is introduced into piston rod side oil chambers 2C, 2C of the group Y through R ports 2E, 2E of the group Y and anti-piston rod side oil chambers 2D, 2D communicate with a tank through P ports 2F, 2F, a movable platen 5 is drawn to a stationary platen 1. On the other hand, the P ports 2F, 2F and R ports 2E, 2E wholly communicated with one another and communicate further with also the R ports 2E, 2E of the hydraulic cylinder of the group Y and a discharge source of the pump, the hydraulic oil to be discharged through anti-piston rod side oil chambers 2D, 2D runs round to the piston rod side oil chambers 2C, 2C and the surplus hydraulic oil is supplied to the piston rod oil chambers 2C, 2C of the groups Z. |
