Bottles and jars – Closures – Cap type
Reexamination Certificate
2000-06-15
2003-03-04
Young, Lee (Department: 3727)
Bottles and jars
Closures
Cap type
C215S343000, C215S344000, C215SDIG001
Reexamination Certificate
active
06527132
ABSTRACT:
TECHNICAL FIELD
The present invention relates to linerless closures for containers including, but not limited to, carbonated beverage containers. More particularly, the invention relates to such closures that are formed of a synthetic plastics material and, preferably, in one piece.
BACKGROUND ART
U.S. Pat. No. 5,423,444 discloses a plastic closure for a container having an externally screw threaded neck, the closure including a top portion and an internally threaded skirt. The closure has an annular sealing rib which projects downwardly from the underside of the top portion. The rib includes a first, substantially cylindrical portion contiguous with the underside of the top portion and lying adjacent to or abutting with the skirt, and a second, frusto-conical, portion contiguous with the end of the first portion distal to the underside of the top portion and extending radially inwardly to a circular free edge. During threaded attachment of the closure with the neck, the second, frusto-conical, portion will be engaged by a free end of the neck and folded back against the first, substantially cylindrical portion of the rib to form a gas tight seal between the neck of the container and the closure.
U.S. Pat. No. 5,609,263 discloses a variant of the above closure in which there is at the free end of the second portion of the rib a thick seal ring of substantially circular cross-sectional shape. The rib and the seal ring are dimensioned to engage the free end of the neck when the closure is threaded onto the neck such that when the neck is fully screwed into the closure its free end crushes the seal ring directly against the inside surface of the top portion of the closure.
The present invention is directed to two arrangements of closure that improve the sealing ability of closures of the type identified in the abovementioned prior art.
DISCLOSURE OF INVENTION
The present invention relates to a closure suitable for mounting onto a container having an opening defined by an end portion of the container, the closure being moulded from a synthetic plastics material and including a top portion and a skirt portion depending from the top portion, an annular sealing rib projecting downwardly from an underside of the top portion, the rib including a first portion which is contiguous with the top portion and having an inner surface, which inner surface lies radially inwardly of the skirt portion, and a second, frusto-conical, portion contiguous with the first portion and separated from the top portion by the inner surface of the first portion, the second portion extending radially inwardly to terminate in a circular edge, the first portion having an internal diameter relative to the external diameter of the end portion of the container such that during attachment of the closure with the end portion of the container, the second frusto-conical portion of the sealing rib will be engaged by a free end of said end portion of the container and folded back at least adjacent the inner surface of the first portion of the rib, the closure being characterised in that the first portion of the rib increases in thickness as it extends away from the top portion of the closure.
In a second aspect, the present invention relates to a closure suitable for mounting onto a container having an opening defined by an end portion of the container the closure being moulded from a synthetic plastics material and including a top portion and a skirt portion depending front the top portion, an annular sealing rib projecting downwardly from an underside of the top portion, the rib including a first portion which is contiguous with the top portion and having an inner surface, which inner surface lies radially inwardly of the skirt portion, and a second, frusto-conical, portion contiguous with the first portion and separated from the top portion by the inner surface of the first portion, the second portion extending radially inwardly to terminate in a circular edge, the closure being characterised in that the sealing rib has a third portion connected to the second portion at or adjacent the circular edge and extending generally in a direction away from the top portion, the third portion being substantially no thicker than the second portion and having a length longer than its thickness, the first portion having an internal diameter relative to the external diameter of the end portion of the container such that during attachment of the closure with the end portion of the container, the second frusto-conical portion of the sealing rib will be engaged by a free end of said end portion of the container and folded back at least adjacent the inner surface of the first portion of the rib, and with the third portion of the rib positioned between the neck of the container and the top portion of the closure.
The closures are preferably provided with a screw thread on the inside surface of the skirt portion adapted to engage with a corresponding thread on an external surface of the end portion of the container. It is, however, possible for the container and the closure to be formed with other complementary attachment means. Such an arrangement could, for instance, comprise snap-on attachment means having a rib on the inside surface of the closure and a corresponding groove on the outside surface of the end portion of the container.
The first portion of the rib is preferably formed radially inwardly of the skirt with an annular space therebetween. It is, however, possible in other embodiments to form the first portion of the rib in abutment with the skirt in the sense that they are continuous. In one embodiment of the above aspects of the invention, the first portion of the rib is observed as a thickening of the skirt portion so that the root of the second portion of the rib is moved inwardly of the part of the skirt portion carrying the screw thread or other attachment means.
In each aspect, the first portion serves to form an abutment towards which the second portion is folded during attachment of the closure with the end portion of a container. Preferably, the second portion will be folded back against the first portion such that it bears against the inner surface of the first portion. This will cause the second portion to bear more strongly against the outside surface of the end portion of the container and so form a better seal with the end portion.
The first aspect of the present invention is directed to the first portion of the rib having a thickness that increases in a direction away from the top portion of the closure. This thickening of the first portion will increase the force of the pressure of the rib against the outside surface of the end portion of the closure. The thickness of the first portion preferably increases at a uniform rate along the length of the first portion however it could do so in a non-uniform manner. The increase in the thickness of the first portion means that the inside and outside surfaces of the first portion will not necessarily be exactly cylindrical. They my respectively taper slightly inwardly and outwardly relative to the axis of the closure in a direction away from the top portion of the closure.
In the second aspect of the present invention, the rib includes a third portion. This third portion is preferably contiguous with the free edge of the second portion, though it may be spaced slightly radially outwardly front it. The third portion projects generally away front the top of the closure. It may join the second portion in an angular disjunction or it may join it in a smooth angular transition from the generally radially inward direction of the second portion to a generally axial direction.
It is of the essence of this second aspect of the present invention that the third portion of the rib be substantially no thicker than the second portion and also be relatively longer in relation to its thickness. It has been found that the sealing qualities of the closure are best improved by providing a thin extension to the second portion of the rib that will wrap around the free end of the end porti
Druitt Rodney Malcolm
Furlong Michael Patrick
Closures and Packaging Services Limited
McDermott & Will & Emery
Merek Joseph C.
Young Lee
LandOfFree
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