Patent Publication Number: US-6981601-B2

Title: Tamper-evident snap-on closure with sealing plug and liner

Description:
TECHNICAL FIELD 
     The present invention relates generally to closures for bottles and like containers, and more particularly to a plastic, snap-on 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. Nos. 4,407,422, 4,497,765, 4,418,828, and 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 require a specialized container “fmish” at the neck portion, and 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&#39;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 is 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. 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 snap-on 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 forwardly 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. Retention of the sealing liner on the sealing plug is enhanced by the provision of an annular retention lip defined by one of the sealing plugs in the sealing liner, with the other of the plug and liner defining an annular retention groove for receiving the retention lip. In the illustrated embodiment, the sealing plug defines an annular retention groove on its outwardly facing surface, with the sealing liner defining an annular sealing lip disposed within an annular channel of the liner, with a free edge of the sealing plug positioned within the annular channel. 
     In one illustrated embodiment, the sealing liner has an axial dimension less than the axial dimension of the sealing plug, with the liner including a central portion positioned generally within the sealing plug. At least one support rib depends from the top wall portion of the closure generally within the sealing plug for supporting the central portion of the liner. In the illustrated embodiment, a pair of support ribs, arranged in generally parallel relationship, are provided. In a current embodiment, the removal tab of the closure projects outwardly from the skirt portion perpendicularly to the one or more support ribs. In an alternate embodiment, an in-situ molded sealing liner is coextensive with the sealing plug, and includes a central portion positioned generally within the sealing plug adjacent the top wall portion of the closure. 
     In order to provide tamper-evidence attendant to removal of the present closure from an associated container, the annular skirt portion of the closure includes a deformable region positioned generally beneath the removal tab. The annular skirt defines a circumferential gap extending above the deformable region, such that the deformable skirt portion is generally separated and distinguished from the portion of the closure immediately thereabove. Undesired deformation of the deformable region of the skirt portion during closure application is avoided by the provision of a bridge element, positioned at the circumferential gap, for bearing axial loads during application of the closure to a 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 tamper-indicating deformable region of the skirt portion having one of the retention beads thereon. In accordance with the illustrated embodiment, an elongated one of the retention beads is provided on the skirt portion opposite the removal tab. The elongated retention bead preferably defines an opening positioned diametrically opposite the removal tab to facilitate manufacture of the present closure. 
     During closure removal, the removal tab of the closure is urged upwardly, with the closure defining a flexure region which extends across the top wall portion thereof, generally between the center of the top wall portion and the removal tab. During removal, the deformable region of the skirt portion initially retained on the container by its retention bead, becomes separated from the top wall portion and removal tab as the closure flexes. As opening movement is continued, the deformable region of the skirt portion is permanently stretched and deformed before the retention bead on the deformable region moves off of the container finish as the closure is completely removed. 
     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 snap-on closure embodying the principles of the present invention; 
         FIG. 2  is a perspective view of the inside of the present closure; 
         FIG. 3  is a perspective view similar to  FIG. 2  showing the inside of the present closure without a sealing liner in place; 
         FIG. 4  is a perspective view of the sealing liner of the present closure; 
         FIG. 5  is a cross-sectional view of the sealing liner shown in  FIG. 4 ; 
         FIG. 6  is a bottom plan view of the inside of the present closure, without the sealing liner; 
         FIG. 7  is a cross-sectional view taken along lines  7 — 7  of  FIG. 6 ; 
         FIG. 8  is a cut-away, perspective view of the present closure; 
         FIG. 8   a  is a view similar to  FIG. 8  illustrating an alternate form of a sealing liner of the present closure; 
         FIG. 9  is a finite element analysis illustration of the present closure when applied to an associated container; and 
         FIG. 10  is a finite element analysis illustration of the present closure during removal from an associated container. 
     
    
    
     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 snap-on closure  10  embodying the principles of the present invention. In the presently preferred form, the closure  10  includes a separately-formed sealing liner  12  for enhancing sealing cooperation with an associated container C. 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 an injection molding. 
     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 forwardly from the skirt portion  16 , and which facilitates manipulation and removal of the closure from the container C by consumers. 
     In the illustrated embodiment, closure  10  is configured to effect a so-called plug seal with the associated container C, and to this end, the closure includes a sealing plug  20  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 C, 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. To this end, the disc-shaped sealing liner  12  defines an annular channel  22  ( FIGS. 4 and 5 ) within which is positioned the free edge of the sealing plug  20 . Retention of the sealing liner  12  on the sealing plug  20  is facilitated by the provision of a retention lip on one of the outwardly facing surface of the sealing plug and the liner, with the other of the sealing plug and liner defining an annular retention groove for receiving the retention lip. In the illustrated embodiment, the outwardly facing surface of the sealing plug  20  defines an annular retention groove  24  which receives an annular retention lip  26  defined by the sealing liner  12  generally within annular groove  22 . 
     It is presently contemplated that in one form, the sealing liner  12  be separately formed from the remainder of closure  10 , and then assembled with the closure by disposition on sealing plug  20 . Formation of the sealing liner  12  by compression molding is presently contemplated, with the liner formed from suitable material such as ethylene vinyl acetate (EVA), or like materials as are known in the art for such applications. As will be recognized by those familiar with the art, these types of liner materials are relatively expensive (as opposed to the polypropylene from which the remainder of the closure is typically formed), and as such, it is desirable to limit the amount of material employed for manufacture of the sealing liner  12 . To this end, the sealing liner  12  is preferably configured to have an axial dimension less than the axial dimension of the sealing plug  20 . In the preferred form, the sealing liner  12  includes a central portion  28  positioned generally within the sealing plug  20  in spaced relationship to the top wall portion  14 . Support of the sealing liner  12  in association with the sealing plug  20  is facilitated by the provision of at least one support rib which depends from the top wall portion  14  generally within the sealing plug for supporting the central portion  28  of the sealing liner. In the illustrated embodiment, a pair of support ribs  30  are provided, with the support ribs  30  arranged in parallel relationship to each other. The one or more support ribs  30  are preferably arranged such that a removal tab  18  projects outwardly from the skirt portion  16  perpendicularly to the support ribs, with the closure thus configured so as to promote flexure during removal generally along a flexure region which extends across the top wall portion generally between the center of the top wall portion and the removal tab  18 . 
     By the above-described configuration of the sealing plug  20  and sealing liner  12 , sealing of the closure  10  with the associated container C is effected generally along the outside surface  32  of the sealing liner  12  where the sealing liner engages the inside surface of the mouth of container C. 
       FIG. 8   a  illustrates an alternate embodiment of the present closure, including a sealing liner  112  molded in situ on the associated modified sealing plug  20 . The sealing liner can be formed by compression molding in position on the sealing plug. In this embodiment, the liner  112  is coextensive with the sealing plug  120 , and includes a central portion  128  adjacent to wall portion  14 . For this embodiment, the closure is formed without support ribs  30 , with the liner preferably including an outwardly facing seal bead  113  generally adjacent a free edge of the sealing plug  120 . 
     As noted, the present closure is preferably configured for snap-on application to the associated container C, and is 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 C, the closure includes at least one, and preferably a plurality of retention beads which project inwardly from the skirt portion  16  of the closure. Notably, the retention beads of the present closure not only effect retention of the closure on the container prior to removal, but further are configured to cooperate with the container for providing tamper-evidence. To this end, the skirt portion  16  of the closure  10  includes a deformable portion  32  positioned generally beneath the removal tab  18 . The deformable region  32  is separated and distinguished from the skirt portion thereabove by a gap  34  which extends above the deformable region  32 . The deformabic region  32  is thus configured for permanent stretching and deformation attendant to closure removal from container C for tamper-evidence, as will be described. In the preferred form, proper seating and application of the closure, including deformable region  32 , on the container C is facilitated by the provision of bridge element  36  positioned at the gap  34  for bearing axial loads during application of the closure to the container. As shown, bridge element  36  is positioned on the skirt portion  16  just above the deformable region  32 , generally at the underside of removal tab  18 . 
     As noted, retention of closure  10  on the associated container is preferably provided by the provision of a plurality of retention beads which are circumferentially spaced. In the preferred form, a retention bead  38  is provided on deformable region  32  of the skirt portion  16 , with an elongated retention bead  40  provided on the skirt portion opposite the removal tab  18 . In the illustrated embodiment, retention bead  40  extends circumferentially of the skirt portion  16  about 180°, and cooperates with retention bead  38  to retain the closure on the container prior to removal. As illustrated, the elongated retention bead preferably defines an opening  42  positioned diametrically opposite the removal tab, with the opening  42  facilitating removal of mold tooling employed for manufacture of the present closure. 
     From the foregoing description, application and removal of the present closure  10  will be readily appreciated. With particular reference to  FIG. 9 , a finite element analysis is illustrated therein, wherein the closure  10  is shown applied to the associated container C. In this position, the sealing liner  12  disposed on sealing plug  20  sealingly engages the inside surface of the mouth of the container C, with the present closure preferably configured to substantially separate and isolate the loads which are created for effecting sealing engagement from those loads which act, via the retention beads of the closure, for retaining the closure in position on the container. The loads exerted upon the plug seal are generally oriented in a radial direction, with the sealing plug and its liner generally tending to slide upwardly during closure removal. 
       FIG. 10  is a finite element analysis illustration of the present closure during removal from the associated container. As will be observed, the closure generally flexes along a flexure region which extends across the top wall portion  14  generally between the center of the closure and the removal tab  18 . During closure removal, the retention bead  38  on deformable region  32  of the skirt portion acts to retain the deformable region on the container, resulting in permanent stretching and deformation of the deformable region as the closure is removed from the container. As the closure is moved upwardly by manipulation of removal tab  18 , the deformable region  32  eventually stretches and deforms sufficiently as to slip off of the container, thus permitting disengagement of the elongated retention bead  40  from the container, and removal of the closure. 
     If desired, the skirt portion  16  of the closure can be configured to define a pair of weakened regions, such as shown in phantom line at  44 , positioned on respective opposite sides of the removal tab  18  to facilitate flexure and removal of the closure. The weakened regions  44  can be suitably molded into the closure  10 , or formed by cutting or scoring after molding, and are positioned generally at respective opposite sides of the flexure region which extends across top wall portion  14 . As noted, support ribs  30  preferably extend in a direction perpendicular to removal tab  18  to facilitate flexing of the closure during removal. 
     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.