Bottles and jars – Closures – Cap type
Reexamination Certificate
1999-10-01
2001-03-20
Newhouse, Nathan J. (Department: 3727)
Bottles and jars
Closures
Cap type
C215S349000, C053S421000, C053S490000
Reexamination Certificate
active
06202872
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to a molded plastic closure, and more particularly to a composite closure including a molded plastic outer cap, and an inner molded sealing liner, wherein the cap and liner are configured for enhanced sealing, particularly when the closure is applied to a container having carbonated or otherwise pressurized contents. The closure liner includes an annular seal bead feature which cooperates with a peripherally reinforced region of the top wall of the closure cap to enhance sealing performance.
BACKGROUND OF THE INVENTION
Molded plastic closures have found increasingly widespread acceptance in the marketplace for all manner of applications, including widespread use on containers having carbonated or otherwise pressurized contents. This type of application can be somewhat problematic, in that gas pressure within the container can tend to deform a plastic closure during normal storage, shipment, and retail sale. This type of deformation of the closure, which is in the nature of a cold flow phenomenon as the gas pressure acts against the inside surface of the closure, can result in outward bowing or “doming” of the top wall portion of a closure. This deformation can inhibit the sealing integrity of the closure, since the deformation can result in diminished sealing engagement between the inside surface of the closure top wall and the upper surface of the associated container.
U.S. Pat. No. 4,497,765, hereby incorporated by reference, discloses a so-called composite closure, and method of formation, which has proven to be very highly effective for packaging of carbonated beverages and the like. This type of closure is particularly configured to form a “top/side seal” with an associated container, by the provision of a sealing liner positioned adjacent the inside surface of the top wall of an outer closure cap of the composite closure. The sealing liner includes an annular sealing portion at the periphery thereof which presents a generally inwardly facing sealing surface. The liner is thus configured to make sealing engagement with both upwardly facing and outwardly facing surfaces of the associated container, for the formation of the desired top/side seal. Experience has shown that in the event that this type of closure is subjected to doming or like deformation, the sealing integrity of the closure is maintained by the inwardly facing sealing surface of the closure liner, even if deformation of the closure results in diminished sealing engagement between the liner and the upwardly facing surface of the container.
While the above-described composite closure construction has proven to be very commercially successful, it is desirable to provide these types of closures with the best possible sealing performance that can be achieved at acceptable cost. Experience has shown that under some storage and handling conditions of containers, closures can be subjected to top-loading which may disrupt the sealing integrity of closures forming top/side seals, as described above. The present invention is directed to a composite closure configured to provide enhanced sealing under the various types of conditions which are typically encountered during shipment and storage of containers having carbonated contents on which the closures are used.
SUMMARY OF THE INVENTION
A composite closure embodying the principles of the present invention includes an outer plastic closure cap, and an inner sealing liner positioned adjacent an inside surface of a top wall portion of the cap. The sealing liner is configured to include a generally inwardly facing sealing portion at the periphery thereof which functions to provide principal or primary sealing engagement with an associated container, by sealing engagement with a generally outwardly facing surface of the container. The sealing liner further includes an annular seal bead positioned for cooperation with the peripheral sealing portion of the liner. The annular seal bead projects downwardly away from the top wall portion of the closure cap, and presents a generally downwardly facing sealing surface for sealing engagement with an upwardly facing surface of the associated container. While the seal bead is generally provided in the present closure as a secondary form of sealing, under certain circumstances, the seal bead can provide as much, or more, sealing cooperation with the associated container than the inwardly facing sealing portion of the liner. In the preferred form, the top wall portion of the outer closure cap includes a relatively thick reinforcing region generally at the periphery thereof which overlies the seal bead of the sealing liner. The reinforcing portion acts together with the sealing liner to maintain the closure in sealing engagement with an associated container, thus providing enhanced sealing properties for the present closure construction.
In accordance with the illustrated embodiment, an outer closure cap of the present composite closure assembly includes a top wall portion, and an annular skirt portion depending from the top wall portion. The skirt portion includes an internal thread formation configured for threaded, cooperating engagement with a like thread formation on an associated container. The skirt portion includes an inwardly extending annular shoulder positioned at the juncture of the top wall portion and the skirt portion. In the illustrated embodiment, the annular shoulder defines an annular recess positioned adjacent the top wall portion.
The present composite closure further includes a sealing liner positioned within the closure cap adjacent the inside surface of the top wall portion. The liner includes a generally inwardly facing sealing portion of the periphery thereof adjacent the annular shoulder and the skirt portion. In the illustrated embodiment, the sealing portion of the liner extends into the annular recess defined by the annular shoulder.
The sealing liner further includes an annular seal bead, as described above, projecting downwardly away from the top wall portion, adjacent the juncture of the top wall portion and skirt portion. The seal bead presents a generally downwardly facing sealing surface for sealing engagement with a generally upwardly facing surface of the associated container. By this configuration, the sealing surface of the seal bead provides sealing in cooperation with the inwardly facing sealing portion of the closure liner.
The annular seal bead has a cross-section configuration that tapers inwardly in a direction away from the top wall portion. In the preferred embodiment, the annular seal bead has a generally convex cross-sectional configuration, and is generally hemispherical in cross-section.
Use of the present closure construction provides a method for sealing a container having pressurized contents during top-loading of the container. The composite closure in accordance with the present invention is applied to a container so that the sealing portion of the liner sealingly engages a generally outwardly facing surface of the container. Attendant to normal storage and shipment, the top wall portion of the closure cap is outwardly deformed under the influence of pressure within the container. Despite such deformation, the sealing portion of the liner is maintained in sealing engagement with the container by virtue of the top/side sealing characteristics of the closure.
During typical handling and storage, the closure is subjected to top-loading in opposition to the outward deformation of the top wall portion. This action urges the annular seal bead of the sealing liner into sealing engagement with a generally upwardly facing surface of the container before the sealing portion of the liner is moved out of sealing engagement with the outwardly facing surface of the container. The timing of the engagement of the annular seal bead with the container top sealing surface during top-loading is such that the annular seal bead will engage the container before significant perturbation of the closure cap, through the application of top-load, result
Powell Mark A.
Russell Mark R.
Smeyak Lawrence M.
Yao Budan
Zurawski Michael R.
Alcoa Closure Systems International
Newhouse Nathan J.
Rockey Milnamow & Katz Ltd.
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