| 摘要 |
PROBLEM TO BE SOLVED: To prevent damages of a sliding member by projecting a thin film to guide the smooth movement of the sliding member into a through hole from an inner edge of the through hole of a cylinder. SOLUTION: A small circular through hole 3 which is an air hole for introducing the outside air into a container is made in a cylinder 2 at the position of the upper limit of a piston 10. A thin film 5 which is n elastically deformable against the bending in a through hole 3 from the whole periphery of an inner edge is integratedly provided in the through hole 3. The margin width of the thin film 5 is preferably >=0.5mm, and its thickness is preferably 0.005-0.3mm. When a piston 10 which is a sliding member 1 is lowered from the position of the upper limit and then elevated, and an upper skirt 8 passes through the through hole 3, a part of the skirt 8 is swollen into the through hole 3, a part with which a swollen hole edge is brought into contact is softly received by the thin film 5 without difficulty while appropriately deflected outwardly, and the movement is guided to move the skirt 8. Thus, the upper skirt 8 passing through the through hole 3 is not damaged. |
