| 摘要 |
A linerless plastic closure has an integral frusto-conical sealing ring that seals with the rim of the neck of a container when the closure is applied thereto. The sealing ring has a hinge portion at an upper end thereof with a wall thickness that is small relative to that of an adjacent portion of the sealing ring, and has a preformed internal circumferential bead positioned to engage the rim at or near its top inner region. As the closure is applied to the container, the outer portion of the sealing ring first engages the rim, and the sealing ring is easily deformed by virtue of the hinge portion. After the bead seats on the rim, the sealing ring is stretched outwardly completely over the rim, with the bead serving to resist stretching from the hinge portion. An internal circumferential shoulder extends downwardly from the inner surface of the top wall adjacent to the side wall of the closure, engages the outer portion of the sealing ring, shapes the sealing ring to the rim, and clamps the outer portion of the sealing ring to the top outer region of the rim. |
