| 摘要 |
PURPOSE:To improve the working efficiency and cut cost by installing a check valve in the first passage for the communication between the first and second oil chambers and installing a valve which is closed when an article contacts the front edge of a piston rod, into the second passage. CONSTITUTION:Passages 8 and 40 for the communication between the first and second oil chambers 5 and 6 are formed. A check valve 9 for preventing the passing of oil from the second oil chamber 6 to the first oil chamber 5 is installed in the first passage 9. The port 15a of a communication hole 15 is positioned in the vicinity of the inner edge of a stem 1, and closed when the stem 11 is pushed from outside into a hole 10 by the distance d1 against the urging force of a spring 12. Therefore. the working efficiency can be improved, and cost can be cut. |
