Tamper-evident plug seal closure

Abstract

A plastic closure for a container includes a top wall portion, an annular skirt portion depending from the top wall portion, and a removal tab projecting downwardly from the skirt portion for manipulation of the closure during removal. A sealing plug depends from the inside surface of the top wall portion for disposition generally within the mouth of an associated container. The closure includes a pair of weakened regions which extend along the skirt portion on respective opposite sides of the removal tab, and which further extend along the closure top wall portion on respective opposite sides of the sealing plug.

Description

TECHNICAL FIELD

The present invention relates generally to closures for bottles and like containers, and more particularly to a plastic, plug seal closure for a container which is configured for convenient removal without openers or the like, and which provides visually discernable tamper-evidence.

BACKGROUND OF THE INVENTION

Various constructions for container closures have been developed over the years in order to provide effective closure and sealing, while permitting convenient closure removal for consumption or use of the container contents. By way of example, use of internally threaded, molded plastic closures has become increasingly widespread by virtue of the sealing integrity which they provide, especially for carbonated beverages, while facilitating convenient removal by consumers. U.S. Pat. No. 4,407,422, No. 4,497,765, No. 4,418,828, and No. 4,938,370, all hereby incorporated by reference, disclose various compression-molded plastic closures which have proven to be very commercially successful, in part due to the tamper-indicating features with which such closures can be provided.

Internally-threaded closures of the above type have, in part, supplanted use of metal, so-called crowns, which have been, and continue to be employed on beverage containers. While closures of this type provide the desired sealing integrity, such closures have typically required use of an opener or like implement to effect their removal from an associated container. While manually-removable “twist-off” crowns are known, such closures can still be difficult for some consumers to remove without use of an opener or the like. Additionally, metal crown closures typically do not include any specific tamper-indicating feature, which can be desirable to assure consumers of a container's integrity.

In view of the foregoing, it is desirable to provide a closure for a container which can be efficiently applied, and easily removed by consumers without an associated opener or like implement. Aside from providing the desired sealing integrity, particularly for carbonated contents, it is desirable to provide a closure which is configured for tamper-evidence.

SUMMARY OF THE INVENTION

The plastic closure embodying the principles of the present invention can be configured for snap-on application to an associated container, and removal by consumers without use of an opener or like implement. Notably, the present snap-on closure is configured to provide tamper-evidence in a manner which is clearly visually discernable by consumers, and is further desirably configured to vent gas pressure from within a container prior to complete closure removal. The present closure is desirably straightforward in configuration, thus facilitating efficient, cost-effective manufacture, and is readily adaptable to existing container finishes, such as commonly employed with metal closure crowns.

A closure embodying the principles of the present invention includes a top wall portion, and an annular skirt portion depending from the top wall portion. In the preferred configuration, the closure includes a removal tab which projects downwardly from the skirt portion, and facilitates convenient removal by consumers without a closure opening implement.

Sealing of the associated container is effected by the provision of a generally cylindrical sealing plug which depends from an inside surface of the top wall portion of the closure. The sealing plug is configured for disposition generally within the mouth of an associated container. Depending on the specific application, the present closure can be provided in a composite form, and include a sealing liner disposed on the sealing plug for sealing engagement with the associated container. The sealing liner may be formed separately, or molded on the sealing plug.

In accordance with the present invention, the present closure provides tamper-evidence attendant to closure removal by the provision of a pair of weakened regions which preferably extend along the annular skirt portion of the closure, on respective opposite sides of the removal tab, and which further extend along the top wall portion on respective opposite sides of the sealing plug. The sealing plug is preferably generally aligned with the portions of the weakened regions extending along the closure skirt, with the weakened regions preferably extending partially about, and in concentric relationship with, the sealing plug.

By this arrangement, removal of the closure from an associated container can be initiated by upward movement of the removal tab, which effects breakage and tearing of the weakened regions in the closure skirt. Tearing of the weakened regions propagates and continues into the top wall portion of the closure, on opposite side of the sealing plug, with continued opening movement of the removal tab acting to disengage and dislodge the sealing plug from within the mouth of the associated container. The closure is clearly visibly permanently altered by this tearing of the weakened regions, thus providing clear tamper-evidence. Additionally, this opening action, with the sealing plug generally separating from the remainder of the top wall portion, desirably effects venting of any gas pressure from within the associated container prior to disengagement of the closure from the associated container.

The closure is retained on the associated container by the provision of at least one inwardly projecting retention bead. In the preferred form, a plurality of inwardly projecting, circumferentially spaced retention beads are provided, with the portion of the skirt portion between the pair of weakened regions having one of the retention beads thereon.

Other features and advantages of the present invention will become readily apparent from the following detailed description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is top perspective view of a closure embodying the principles of the present invention;

FIG. 2 is a side elevational view of the present closure;

FIG. 3 is a bottom plan view showing the inside of the present closure;

FIG. 4 is a cross-sectional view of the present closure taken along lines 4-4 of FIG. 3.

DETAILED DESCRIPTION

While the present invention is susceptible of embodiment in various forms, there is shown in the drawings, and will hereinafter be described, a presently preferred embodiment, with the understanding that the present disclosure is to be considered as an exemplification of the invention, and is not intended to limit the invention to the specific embodiment illustrated.

With reference to the drawings, therein is illustrated a closure 10 embodying the principles of the present invention. In the presently preferred form, the closure 10 includes a sealing liner 12, which can be separately formed, or molded, in situ, for enhancing sealing cooperation with an associated container. However, as will be evident from the present disclosure, a closure configured in accordance with the principles disclosed herein need not include the separate sealing liner 12. Closure 10 can be fabricated in accordance with conventional manufacturing techniques, including compression molding and injection molding.

While it is presently preferred that closure 10 be configured for snap-on application to an associated container, the closure can be otherwise configured, such as to facilitate screw-on or twist-on application to a container. The container may be provided with external or internal threads to facilitate application and retention in this fashion.

The closure 10 includes a generally circular top wall portion 14, and an annular skirt portion 16 which depends from the top wall portion. In the preferred form, the closure 10 includes a lever-like removal tab 18 which projects downwardly from the skirt portion 16, and which facilitates manipulation and removal of the closure from the container by consumers.

Closure 10 is configured to effect a so-called plug seal with the associated container, and to this end, the closure includes a sealing plug 20 (FIG. 4) depending from an inside surface of the top wall portion 14 for disposition generally within the mouth of the associated container. While the sealing plug 20 may be configured for sealing engagement with the interior of the container, it is presently preferred that the closure 10 include the sealing liner 12 for disposition on the sealing plug, such that the sealing liner is positioned for sealing engagement with the container.

It is presently contemplated that the sealing liner 12 be formed by injection molding in situ, that is, by a secondary process for molding the liner 32 directly on the sealing plug 20. Alternatively, the liner 32 can be separately molded, such as by compression molding, and then assembled with the closure by disposition on sealing plug 20. Formation of the sealing liner 12 from suitable material such as ethylene vinyl acetate (EVA), or like materials as are known in the art for such applications, is contemplated. By the above-described configuration of the sealing plug 20 and sealing liner 12, sealing of the closure 10 with the associated container is effected generally along the outside surface of the sealing liner 12 where the sealing liner engages the inside surface of the mouth of the container.

The liner 12 is preferably coextensive with the sealing plug 20, and includes a central portion 28 adjacent to wall portion 14.

As noted, the present closure is preferably configured for snap-on application to the associated container, and can be configured for retention on the container without resort to thread formations or the like. In order to retain the closure 10 on the circumferential bead of the container, the closure includes at least one, and preferably a plurality of retention beads 30 which project inwardly from the skirt portion 16 of the closure. As shown, one of the retention beads 30 is provided on skirt portion 16 generally between the weakened regions 32, generally above removal tab 18.

In accordance with the present invention, tamper-evident removal of closure 10 from an associated container is effected by the provision of a pair of frangible weakened regions 32, or frangible tear lines, which extend along the skirt portion 16 of the closure on respective opposite sides of removal tab 18, and which further extend along top wall portion 14 on respective opposite sides of sealing plug 20. The weakened regions are provided in the form of relatively thin portions of the closure, and are preferably formed by molding, or may be formed by scoring or cutting the closure. The relatively thin weakened regions preferably have a thickness in the range of about 0.005 to 0.010 inches, with the weakened regions having a thickness of 0.007 inches in a current embodiment, wherein the closure is formed from polypropylene.

It is presently preferred that the weakened regions 32 be formed along the inside surfaces of skirt portion 16 and top wall portion 14, as illustrated, but it will be understood that the weakened regions can be formed to extend along either or both of the inside and outside surfaces of the closure 10. As will be observed in FIG. 3, the sealing plug 20 is generally aligned with those portions of the weakened regions 32 which extend along the skirt portion 16, with the weakened regions 32 preferably extending in concentric relationship with sealing plug 20. The weakened regions 32 preferably extend along the top wall portion partially around the sealing plug 20, with the presently preferred configuration being such that the weakened regions 32 extend partially around the sealing plug on the side of the sealing plug opposite the removal tab. The weakened regions each extend around the sealing plug 20 to a point spaced at an angle α from the center of removal tab 18, with angle α being 135° in a current embodiment (i.e., the ends of the weakened regions on top wall 14 are spaced apart at about 90°).

By this configuration of the weakened regions 32, tamper-evident closure removal is facilitated. Upward lever-like manipulation of removal tab 18 results in fracture and tearing of the weakened regions 32 extending along the skirt portion 16. Tearing and fracture of the weakened regions continues and propagates from the skirt portion into the top wall portion 14, with continued upward manipulation of removal tab 18 acting to dislodge sealing plug 20 from the mouth of the container. The preferred disposition of one of the retention beads 30 on the portion of the skirt portion positioned between weakened regions 32, generally above removal tab 18, permits tearing and opening of the closure in this fashion while the remainder of the retention beads 30 remain generally in engagement with the finish of the container. As manipulation of removal tab 18 acts to dislodge sealing plug 20 from the container, any gas pressure within the container can be vented, while the closure 10 generally remains in place on the container. Thus, that portion of the closure positioned generally between the weakened regions 32, including the removal tab 18, the adjacent skirt portion 16, and the sealing plug 20 move generally as an integrated unit, as the removal tab is manipulated, and flex upwardly with respect to the remainder of the closure, which is retained in position by the retention beads 30.

After tearing and fracture of the weakened regions 32, the structural integrity of closure 10 is sufficiently weakened as to permit the closure to be readily removed from the associated container generally by outward and upward deformation of skirt portion 16. By virtue of the resilience of the polymeric material from which the closure 10 is formed, the closure can be re-applied to the container to effect an adequate seal for any contents of the container which may remain after its initial removal. However, while re-application of the closure 10 to the container after initial removal is possible, it is not contemplated that such re-application is intended to effect the same degree of sealing integrity with the container as when the closure is initially applied. In any event, initial removal of the closure provides clearly visible evidence of opening, by virtue of the clearly distinct tearing and fracture of weakened regions 32, thus providing clear evidence of opening for consumers, even if the closure 10 is subsequently reapplied to the container.

From the foregoing, it will be observed that numerous modifications and variations can be effected without departing from the true spirit and scope of the novel concept of the present invention. It is to be understood that no limitation with respect to the specific embodiment illustrated herein is intended or should be inferred. The disclosure is intended to cover, by the appended claims, all such modifications as fall within the scope of the claims.

Claims

1. A closure for a container comprising:

a top wall portion;

an annular skirt portion depending from said top wall portion;

a removal tab projecting from said skirt portion; and

a sealing plug depending from an inside surface of said top wall portion for disposition generally within a mouth of an associated container,

said closure including a pair of frangible weakened regions extending along said annular skirt on respective opposite sides of said removal tab, and further extending along said top wall portion on respective opposite sides of said sealing plug.

2. A closure in accordance with claim 1, including:

a sealing liner disposed on said sealing plug for sealing engagement with said container.

3. A closure in accordance with claim 2, wherein:

said sealing liner is coextensive with said sealing plug, and includes a central portion positioned generally within said sealing plug adjacent said top wall portion.

4. A closure in accordance with claim 1, wherein:

said annular skirt portion includes at least one inwardly projecting retention bead for retaining said closure on said container.

5. A closure in accordance with claim 4, wherein:

said annular skirt portion includes a plurality of inwardly projecting, circumferentially spaced retention beads, one of said retention beads on said skirt portion generally between said pair of weakened regions.

6. A closure in accordance with claim 1, wherein:

said pair of weakened regions extend along said top wall portion partially around said sealing plug.

7. A closure in accordance with claim 1, wherein:

said pair of weakened regions extend along said top wall portion in concentric relationship with said sealing plug.

8. A closure in accordance with claim 7, wherein:

said pair of weakened regions extend partially around said sealing plug on the side of said sealing plug opposite said removal tab.

9. A closure in accordance with claim 7, wherein:

said weakened regions comprise relatively thin portions of said closure, having a thickness of about 0.005 to 0.010 inches.

10. A closure for a container, comprising:

a top wall portion;

an annular skirt portion depending from said top wall portion, said skirt portion including at least one inwardly projecting retention bead;

a sealing plug depending from an inside surface of said top wall portion for disposition generally within a mouth of an associated container; and

a sealing liner disposed on said sealing plug for sealing engagement with said containers,

said closure including a pair of weakened regions extending along said top wall portion on respective opposite sides of said sealing plug.

11. A closure in accordance with claim 10, wherein:

said pair of weakened regions extend along said top wall portion partially around said sealing plug.

12. A closure in accordance with claim 10, wherein:

said pair of weakened regions extend along said top wall portion in concentric relationship with said sealing plug.

13. A closure in accordance with claim 12, wherein:

said weakened regions comprise relatively thin portions of said closure, having a thickness of about 0.005 to 0.010 inches.

14. A closure in accordance with claim 10, including:

a removal tab projecting downwardly from said skirt portion.

15. A closure in accordance with claim 14, wherein:

said pair of weakened regions further extend along said skirt portion on respective opposite sides of said removal tab.

16. A closure in accordance with claim 15, wherein:

said closure is configured for snap-on application, and

said skirt portion includes a plurality of circumferentially spaced, inwardly projecting retention beads, with one of said retention beads being positioned generally between said weakened regions extending along said skirt portion.

17. A closure in accordance with claim 15, wherein:

said sealing plug is generally aligned with the portions of said pair of weakened regions extending along said skirt portion.