Patent ID: 6968976

Claim:
A valve mechanism adapted for a mouth portion of a tube-type fluid container, comprising: a valve seat portion having a single opening through which a fluid passes, said valve seat portion having (I) an annular convex portion along the opening and (II) an annular step at its periphery, wherein a tip of the annular convex portion and a top surface of the annular step are substantially of equal height; a disc-shaped valve portion comprising: (i) an annular supporting portion which is in contact with the annular step, (ii) a closing portion for closing the opening at the tip of the annular convex portion, said closing portion having an outer diameter smaller than an inner diameter of the annular supporting portion and larger than an inner diameter of the opening, and having a convex shape toward the opening; and (iii) multiple connecting portions connecting the closing portion to the annular supporting portion to urge the closing portion against the tip of the annular convex portion along the opening, wherein the annular supporting portion, the closing portion, and the multiple connecting portions are integrally formed; and an annular fixing portion for affixing the valve portion to the valve seat portion by interposing the supporting portion between the fixing portion and the valve seat portion.