Patent Publication Number: US-7588155-B2

Title: Beverage container closure

Description:
This application claims priority under 35 U.S.C. 119(c) to U.S. Provisional Application Serial No. 60/288,940, filed May 4, 2001, which is expressly incorporated by reference herein. 
    
    
     BACKGROUND AND SUMMARY 
     The present disclosure relates to a closure for a beverage container and particularly to a closure configured to close an open mouth formed in a threaded neck of a beverage container. More particularly, the present disclosure relates to a “snap-on, screw-off” closure for the neck of a beverage container. 
     Milk, juice, and other beverages are dispensed into jugs or containers at a bottling plant. A closure is then mounted on the container neck to close a liquid inlet/outlet opening formed in the container neck. Closures are sized and shaped to mate with container necks to minimize leakage of liquid from a closed container during shipment of filled containers from a bottling plant to a wholesale or retail store. 
     Some beverage containers, such as one gallon milk or orange juice jugs, are extrusion blow-molded using a polyethylene plastics material. Other beverage containers of the type used to store “sport” drinks are stretch blow-molded using a PET plastics material. In most cases, external threads are formed on the open-mouth necks of these containers to mate with a container closure formed to include mating internal threads. 
     Container closures are usually made of low-density polyethylene (LDPE) and configured to be snapped onto the neck using a capping machine at the bottling plant and screwed on and off the neck by a consumer at home or elsewhere. Such “snap-on, screw-off” style closures often include many fine interior threads with many separate thread leads to enable a bottler to close the open mouth formed in the container neck by applying downward pressure on the closure to “snap” it into place on the neck of a filled container. Nevertheless, a consumer is able to twist and unscrew the threaded closure to remove it from the threaded neck of the container to access the liquid in the container. 
     In accordance with the present disclosure, a beverage container closure comprises a cap adapted to be coupled to an open-mouth neck of a beverage container and a monolithic cap liner coupled to an interior surface of the cap. The cap liner includes concentric seal rings adapted to engage an annular rim provided on the beverage container neck to establish a sealed connection with the annular rim once the cap is installed on the container neck to close the open mouth formed in the container neck. At least one of the seal rings is splayed relative to the annular rim during installation of the cap on the container neck to form a seal between the cap and the beverage container. 
     Additional features of the present disclosure will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The detailed description particularly refers to the accompanying figures in which: 
         FIG. 1  is a perspective view of a closure mounted on a neck of a container; 
         FIG. 2  is an exploded perspective assembly view showing a round monolithic cap liner sized to fit into an interior region formed in a cap and mate with an annular rim formed in the container neck when the cap is coupled to the container neck as shown, for example, in  FIG. 3 ; 
         FIG. 3  is a perspective view similar to  FIG. 2  showing use of the cap to retain the monolithic cap liner in a position closing an open mouth formed in the container neck and establishing an annular seal with the annular rim formed in the container neck to block leakage of liquid from the container through the open mouth when the cap is coupled to the container neck; 
         FIG. 4  is an enlarged, perspective view of the underside of the monolithic cap liner of  FIGS. 2 and 3  before the cap liner is inserted into and attached to the cap showing concentric first and second seal rings included in the cap liner; 
         FIG. 5  is a bottom view of the monolithic cap liner of  FIGS. 2-4 ; 
         FIG. 6  is an enlarged sectional view taken along line  6 - 6  of  FIG. 5  showing cross-sectional views of a first embodiment of first and second seal rings; 
         FIG. 7  is a side elevation view of the closure of  FIGS. 1 and 3 ; 
         FIG. 8  is a top plan view of the closure of  FIG. 7 ; 
         FIG. 9  is a bottom view of the closure of  FIG. 7  showing the monolithic cap liner in the cap; 
         FIG. 10  is an enlarged sectional view of the closure taken along line  10 - 10  of  FIG. 8  showing the monolithic cap liner coupled to a downwardly facing interior surface of the top wall of the cap to cause the concentric first and second seal rings to extend downwardly away from the top wall of the cap; 
         FIG. 11  is a sectional view showing a closure including a cap and a monolithic cap liner as the closure is being lowered toward a container to mate with a threaded neck of the container; 
         FIG. 12  is a partial sectional view similar to  FIG. 11  showing retention of the monolithic cap liner in a sealed mouth-closing position on the annular rim of the container neck once the cap has been coupled to the container neck; and 
         FIGS. 13-16  show partial cross-sectional views of other embodiments of first and second seal rings in a monolithic cap liner in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     A cap liner  10  is coupled to an inner portion of a cap  12  to provide a beverage container closure  14  as suggested, for example, in  FIGS. 1-3 . Closure  14  mounts on a neck  16  of a container  18  to close an open mouth  20  formed in neck  16 . Cap liner  10  includes concentric first and second seal rings  21 ,  22  that contact an upwardly facing substantially flat surface  23  of an annular rim  24  included in neck  16  to establish an “annular seal” therebetween when cap  12  is coupled to neck  16  (as shown in  FIGS. 1 ,  3 , and  12 ) so that leakage of liquid (not shown) from container  18  through open mouth  20  is blocked. mouth  20  is blocked. 
     Cap liner  10  includes a mount  26  having a top surface  28  arranged to mate with cap  12  and an opposite bottom surface  30  arranged to support the concentric first and second seal rings  21 ,  22  as suggested in  FIGS. 4-6 . In the illustrated embodiment, mount  26  is shaped to provide a round disk. Also, in the illustrated embodiment, cap liner  10  is monolithic and made of a plastics material as suggested in  FIG. 6 . 
     Mount  26  of cap liner  10  includes a round inner web  32  and an annular outer web  34  surrounding round inner web  32  as suggested in  FIGS. 3 and 6 . Concentric first and second seal rings  21 ,  22  depend from annular outer web  34  as suggested in  FIG. 6 . Inner web  32  includes an outer peripheral portion terminating at first seal ring  21  to cause first seal ring  21  to surround inner web  32 . Inner web  32  includes a central dome  36  formed to include a dome receiver cavity  38  having an opening in top surface  28 . Inner web  32  also includes a web membrane  40  arranged to surround central dome  36  and extend radially outwardly from central dome  36  to first seal ring  21 . 
     First seal ring  21  includes a wide annular base appended to annular outer web  34  of mount  26  and a narrower annular crest  41  positioned to lie in spaced-apart relation to annular outer web  34  as shown in  FIG. 6 . First seal ring  21  also includes an inclined radially inwardly facing surface  43  that is arranged to cooperate with bottom surface  30  of web membrane  40  of inner web  32  to define an included angle 100 of about 100° (e.g., 99.727°). In the illustrated embodiment, surface  43  has a first frustoconical shape. First seal ring  21  also includes an inclined radially outwardly facing surface  44  that is arranged to cooperate with bottom surface  30  of web membrane  40  of inner web  32  to define an included angle 60 of about 60° (e.g., 60.266°). In the illustrated embodiment, surface  44  has a second frustoconical shape. Annular crest  41  is rounded in cross-section and arranged to interconnect the inclined radially inwardly and outwardly facing surfaces  43 ,  44  as suggested in  FIGS. 4 and 6 . 
     Second outermost seal ring  22  includes a wide annular base appended to annular outer web  34  of mount  26  and a narrower annular crest  42  positioned to lie in spaced-apart relation to annular outer web  34  as shown in  FIG. 6 . Second seal ring  22  also includes an inclined radially inwardly facing surface  45  that is arranged to cooperate with bottom surface  30  of web membrane  40  of inner web  32  to define an included angle  120  of about 120° (e.g., 119.744°). In the illustrated embodiment, surface  45  has a frustoconical shape. Second seal ring  22  also includes a cylindrical radially outwardly facing surface  46 . Annular crest  42  is rounded in cross-section and arranged to interconnect surfaces  45  and  46  as suggested in  FIGS. 4 and 6 . 
     As shown best in  FIG. 6 , first seal ring  21  has a profile height  51  extending from bottom surface  30  of web membrane  40  of inner web  32  to annular crest  41 . In the illustrated embodiment, the profile height  51  is about 0.040 inch (1.02 mm). Second seal ring  22  has a profile height  52  extending from bottom surface  30  of web membrane  40  of inner web  32  to annular crest  42 . In the illustrated embodiment, the profile height  52  is about 0.030 inch (0.76 mm). Thus, profile height  51  of first seal ring  41  is greater than profile height  52  of second seal ring  42 . 
     Various dimensions associated with cap liner  10  are shown in  FIG. 6 . The illustrated cap liner  10  is sized for use in closing a container neck having a 38 mm liquid inlet/outlet opening. For containers of different size, the dimensions of cap liner  10  (and cap  12 ) shall be adjusted proportionately to match the size of the selected liquid inlet/outlet opening in the container neck. Thickness  53  of mount  26  is about 0.0145 inch (0.368 mm). Cap liner  10  has a center line  11  shown in  FIGS. 4 and 6 . Dimension  54  is about 0.609 inch (15.468 mm); dimension  55  is about 0.620 inch (15.748 mm); dimension  56  is about 0.646 inch (16.408 mm); dimension  57  is about 0.651 inch (16.535 mm); and dimension  58  is about 0.679 inch (17.246 mm). 
     Cap liner  10  is formed from an elastomeric material with a preferred Shore A durometer hardness of 58±3, although materials with hardness readings ranging from 50 to 65 are suitable. The use of substantially harder materials will impair the reliability of the seal since harder materials may not deform sufficiently which can cause deformation of the cap skirt during forceful tightening (i.e., torquing). The preferred cap liner material is sold under the trade name POLY SEAL 555 by DSChemie, Bremen, Germany. That material is a blend of a natural rubber base, HDPE, EVA for improved adhesion to the cap, and an amide wax for improved performance in cooler temperature ranges. Examples of suitable materials for use in cap liner  10  include synthetic or natural rubber, ethylene vinyl alcohol (EVA), polyethylene teraphthalate, polyvinyl chloride, linear low-density polyethylene, polystyrene, thermoplastic elastomers, and/or soft polypropylene. Optionally, the material may be a laminate of one or more of such compounds of mixtures of one or more of such compounds. The sealing liners typically used for carbonated beverage containers have a Shore A durometer hardness reading between 85 and 95. Accordingly, such sealing liners are not suitable for use in the cap liner disclosed herein. 
     Cap liner  10  is formed using a compression molding method which includes extrusion of the sealer material onto the center of a cap through a pick-up nozzle. A sensor measures the gram weight of the sealer material extruded and provides a signal to the pick-up nozzle to cease the sealer fluid flow at a predetermined level, typically between 0.440 to 0.460 grams, for a 38 mm opening cap. The cap and the material cools during transportation via conveyor to a compression station. Just prior to compression, the sealer material has cooled to about 215° C. and is semi-solid. A compression punch is then brought down upon the sealer material under high pressure. The compression punch has a profile which is machined to be a mirror image of the cap liner  10  having a plurality of sealing surfaces as described above. The sealing material adheres to cap  12  without use of adhesives or any further addition of heat to cap liner  10  or cap  12 . It is within the scope of this disclosure to adhere cap liner  10  to cap  12  so as to cause cap liner  10  to hold fast or stick onto cap  12  by or as if by gluing, suction, grasping, or fusing. In a further quality control step, air pressure of 2 bar is sent over cap  12  and cap liner  10  to ensure the integrity of the bond between cap liner  10  and cap  12 . The preferred apparatus for performing this method of forming cap liner  10  is in the KDP50-24 Plastic Liner Molding Machine sold by Oberburg Enbineering AG, Ementalstrasse 137, CH-3414, Oberburg, Switzerland. 
     It is contemplated that cap liner  10  is appropriate for large-mouthed containers for use with non-carbonated fluids, such as milk or fruit juice. The “double” seal ring configuration of cap liner  10  requires less compression of sealing rings  21 ,  22  prior to forming a stable seal than single-ridge sealing liners used previously for such containers. This feature provides a lower torque requirement for complete closure and formation of a reliable seal between cap  12  and container neck  16 . The reduced compression required to form a seal provided by cap liner  10  also helps prevent an “over-torque” situation since the cap threads of cap  12  are prevented from traveling too far down the length of the neck threads of neck  16  so that they pass or nearly pass the neck threads and can easily jump over them. The lowering of the torque requirement for sealing of closure  14  simplifies the container filling and capping procedure. The broader the range between the amount of torque needed for a reliable seal and the torque that would cause an over-torque situation is defined as the operational range of torque for a capping apparatus. Control of the torque applied to the container in production has been a problem in the past which cap liner  10  overcomes by maximizing the operational torque range. For cap liner  10 , the sealing torque is preferably about 8 inch-pounds and varies, for example, between 8 and 10inch-pounds The over-torque failure of the cap is 18 inch pounds and is preferably between 16 and 24 inch-pounds. 
     It is preferred that first and second seal rings  21 ,  22  are tapered so that each ring has a wider base portion and a narrower sealing portion (when viewed in cross-section) so that the seal rings initially deform more readily during contact with upwardly facing surface  23  of annular rim  24  of container neck  16  of the lip  70  and then deforms less readily after the initial contact. It is also preferred that the inner first seal ring  21  has a higher crest than the outer second seal ring  22  so that upwardly facing surface  23  of annular rim  24  initially contacts crest  41  and radially outwardly facing surface  44  of the inner first seal ring  21 . As a result of this preferred configuration, the inner first seal ring  21  first contacts upwardly facing surface  23  of annular rim  24  and begins to deform inwardly toward the central axis of the container neck  16  and the outer second seal ring  22  next contacts upwardly facing surface  23  of annular rim  24  and is deformed substantially downwardly. The “splayed” deformation of the inner first seal ring  21  is best shown (in slightly exaggerated form) in  FIG. 12 . In production-like settings, it has been observed that the inner first seal ring  21  becomes splayed away from the central axis of the container neck  16  in a small percentage of installed closures  14 . Although such an outwardly preferred splayed seal is not preferred, it has been observed to provide a reliable seal. The splayed deformation of at least one of first and second seal rings  21 ,  22  helps ensure that a reliable seal is formed even when the neck  16  of the container  18  is outside of specified dimension tolerances. 
     Additional cap liner designs are illustrated in  FIGS. 13-16 , which illustrations are similar to the cross-sectional view of cap liner  10  provided in  FIG. 6 . In each case, the “profile height” of the radially inner seal ring is greater than the profile height of the adjacent radially outer seal ring. 
     In the embodiment shown in  FIG. 13 , cap liner  110  includes mount  126  and concentric first and second seal rings  121   122 . Each of surfaces  143 ,  144 ,  145 ,  146  has a convex cross-sectional shape as shown, for example, in  FIG. 13 . Radially inwardly facing surface  145  of second seal ring  122  is arranged to lie in confronting relation to and merge with radially outwardly facing surface  144  of first seal ring  121  at circular junction  120 . First seal ring  121  includes annular crest  141  and second seal ring  122  includes annular crest  142 . 
     In the embodiment shown in  FIG. 14 , cap liner  210  includes mount  226  and concentric first and second seal rings  221 ,  222 . First seal ring  221  has a cross-sectional shape in the form of an isosceles triangle and second seal ring  222  has a cross-sectional shape in the form of a right triangle. Each of surfaces  243 ,  244 ,  245  has a frustoconical shape and surface  246  has a cylindrical shape. Radially inwardly facing surface  145  of second seal ring  222  is arranged to lie in confronting relation to and merge with radially outwardly facing surface  244  of first seal ring  222  at circular junction  220 . First seal ring  221  includes annular crest  241  and second seal ring  222  w includes annular crest  242 . 
     In the embodiment shown in  FIG. 15 , cap liner  310  includes mount  326  and concentric first and second seal rings  321 ,  322 . First seal ring  321  includes a flat annular crest  341  and second seal ring  322  includes a flat annular crest  342 . First seal ring  321  includes a cylindrical radially inwardly facing surface  343  and a frustoconical radially outwardly facing surface  344 . Second seal ring  322  includes a cylindrical radially outwardly facing surface  346  and a frustoconical radially inwardly facing surface  345  that is arranged to lie in confronting relation to and merge with surface  344  of first seal ring  321  at circular junction  320 . 
     In the embodiment shown in  FIG. 16 , cap liner  410  includes mount  426  and concentric first and second seal rings  421 ,  422 . First seal ring  421  includes annular crest  441  and second seal ring  422  includes annular crest  442 . First seal ring  421  includes a cylindrical radially inwardly facing surface  443  and second seal ring  422  includes a cylindrical radially outwardly facing surface  446 . A radially outwardly facing surface  444  of first seal ring  421  includes a first portion  444   a  having a cylindrical shape positioned to lie adjacent to mount  426  (e.g., disk) and a second portion  444   b  having a frustoconical shape positioned to lie between first portion  444   a  and annular crest  441  and in spaced-apart relation to mount  426 . A radially inwardly facing surface  445  of second seal ring  422  includes a first portion  445   a  having a cylindrical shape positioned to lie adjacent to mount  426  (e.g., disk) and a second portion  445   b  having a frustoconical shape positioned to lie between first portion  445   a  and annular crest  442  and in spaced-apart relation to mount  426 . An annular surface extends between first portion  444   a  and first portion  445   a  as shown in  FIG. 16 . 
     Cap  12  includes a top wall  62  and an annular skirt  64  depending from top wall  62  to form an interior region  66  as shown, for example, in FIGS.  2  and  10 - 12 . Cap  12  also includes a tamper band  68  coupled to annular skirt  64  by means of frangible bridges  69 . 
     In the illustrated embodiment, annular skirt  64  of cap  12  has a total of four threads  70  with four leads  71  formed in the inner surface  72  of annular skirt  64 . In this embodiment, the multiple threads and multiple thread leads assist in providing skirt  64  with sufficient flexibility to provide a snap-on/twist-off capability. The multiple threads  70  are preferably sized, angled, and pitched so that they can slide over container neck threads  73  in response to downward axial pressure applied during bottling. A wide variety of numbers of threads having differing length, height, pitch, and angle of opposite faces may be used in skirt  64 . Preferably, for snap-on/twist-off skirts, the number of threads is between four and eight, the height of the threads is about 0.027 inch (0.685 mm) and between about 0.025 inch (0.635 mm) to about 0.035 inch (0.889 mm); the pitch of the threads is preferably 0.047 inch (1.193 mm) and varies from about 0.045 (1.143 mm) to about 0.060 (1.524 mm); the angle defined by opposite faces  70   a ,  70   b  of the threads  70  is preferably 30° and varies from about 25° to about 40°; and each thread  70  preferably extends circumferentially about 220° around the cylindrical inner surface of annular skirt  64 , but may extend circumferentially between 180° and 240°. 
     Annular skirt  64  is preferably made of high-density polyethylene (HDPE”) material and formed by a conventional injection-molding process. Preferably, the HDPE cap  12  is made from an HDPE resin having a density of about 0.95. It is further contemplated that caps  12  using cap liner  10  may be formed from LDPE, a blend or copolymer of LDPE and HDPE, or other lightweight, inexpensive thermoplastic materials suitable for injection-molding. The use of HDPE material, however, allows the use of a substantially thinner annular wall for annular skirt  64  and therefore requires significantly less material to form than the annular wall of conventional LDPE caps. Annular skirts  64  designed in accordance with the disclosure herein are flexible enough to jump threads during application of downward axial pressure in the course of bottling and have improved resistance to over-torque, “false positive” tamper evidence, as well as deformation during rough handling. The thickness of annular skirt  64  is defined as one-half of the distance between the exterior wall dimension and the thread major dimension and is preferably about 0.027 inch (0.685 mm). This reduction in the thickness of the annular wall  23  results in a cap which may weigh as much as 27% less than a conventional skirt made of LDPE of similar design. The result is an HDPE skirt which preferably weighs as little as 0.73 grams (excluding the weight of the tamper-evident band and sealing liner). In contrast, conventional LDPE cap skirts of similar design typically weighted at least 0.93 grams. 
     As shown in  FIGS. 1 and 2 , annular skirt  64  has a number of vertical ribs  65  formed on the exterior surface of annular skirt  64 . The ribs  65  preferably extend about 0.014 inch (0.355 mm) radially outwardly from the exterior surface of annular skirt  64  to a flattened rib outer surface. Ribs  65  have angled side surfaces which are preferably angled at about 60° from one another. The ribs  65  are preferably slightly drafted about 2° from their base to their upper end to assist in removal from an injection mold. The ribs  65  provide a high-friction surface to assist in gripping skirt  64  of cap  12  when it is rotated during bottling or opening/closing by the end user. Preferably, the skirt  64  has a total of 75 ribs on the exterior surface of annular skirt  64 , but may have from about 70 to about 100 ribs. Many prior cap designs included over 100 ribs on the exterior of the skirt. Removal of 25 ribs can provide up to an additional 10% decrease in skirt weight while maintaining a suitable high-friction surface on the exterior surface of skirt  64 . By combining the “reduced ribs” feature and “thin walls” feature, caps with HDPE skirts weighing as little as 0.73 grams (excluding the weight of the tamper-evident band and sealing liner) have been formed. The HDPE cap  12  with cap liner  10  exhibits maximum torque resistance, resistance to deformation, and tamper evidence performances. 
     As can be best seen in  FIGS. 2 ,  10 , and  11 , frangible bridges  69  include both angled bridges  69   a  and vertical bridges  69   b  connecting annular skirt  64  to the tamper-evident band  68 . Preferably, band  68  included at least eight bridges, including two pairs of angled bridges and two pairs of vertical bridges, although other combinations of bridges may be used. The use of HDPE material provides frangible bridges which are significantly more resistant to inadvertent breaking or stretching which can lead to “false positive” evidence of tampering than bridges formed from LDPE. The lower edge of annular skirt  64  is defined by a shelf extending axially outwardly so that it has a slightly greater exterior diameter than the remainder of annular skirt  64 . A plurality of spaced-apart pads  59  extend down from the lower edge of annular skirt  64 . The outer diameter of pads  59  preferably match the outer diameter of the band  68 . The pads  59  provide a surface for the upper edge of the band  68  to bear against when downward axial pressure is applied to the cap during bottling and when upward axial pressure is applied to the bottom edge of the band  68  to assist in ejection of the skirt  64  from the injection mold. 
     The exterior and interior diameters of the band  68  are slightly larger than those of annular skirt  64  (other than at the pads  59 ) to allow the band  68  to fit over the annular rim  24  on the container neck  16 . The band  68  has a plurality of ridges  75  formed on its interior surface  76 . The ridges  75  have an angled lower surface  77  and a bridge-severing surface  78  extending transversely from the interior surface  50 . The lower surface  77  of the ridges  75  are angled to ease passage of the skirt  64  and band  68  over the rim  24  on neck  16  during the application of downward axial pressure on the cap  12  in the course of bottling. The bridge-severing surface  78  of the ridges  75  are designed to engage the rim  24  on the neck  16  of the container  18  when the cap  12  is twisted for removal. The engagement between the bridge-severing surface  78  and rim  24  on the neck  16  as the skirt  64  is lifted and rotated breaks the frangible bridges  69  so that the band  68  is retained on the neck  16  of the container  18 . Although bridge-severing surface  78  is shown as being disposed on a series of spaced-apart ridges, it is contemplated that a continuous bridge-severing surface could be provided by use of a continuous rim extending transversely from the interior surface of the band  68 , rather than spaced-apart ridges. 
     In accordance with the disclosure herein, a method is provided to establish a sealed connection between cap  10  and neck  16  of beverage container  18  to close open mouth  20  formed in container neck  16 . First and second seal rings  21 ,  22  included in cap liner  10  are moved downwardly in direction  90  toward annular rim  24  formed in container neck  16  as suggested in  FIG. 11 . Such movement is accomplished by moving the cap  12  carrying cap liner  10  in direction  90  toward container neck  16 . Thereafter, cap  10  is moved relative to container  18  to splay at least one (and perhaps both) of first and second seal rings  21 ,  22  relative to annular rim  24  upon contact of first and second annular rings  21 ,  22  with upwardly facing surface  23  of annular rim  24  to form a seal between cap  12  and beverage container  18 . By providing concentric first and second seal rings  21 ,  22 , a seal is established between cap  12  and container neck  16  in situations where container neck  16  is characterized by a poor quality neck finish owing, for example, to inconsistent extrusion blow molding of beverage container  18 . “Primary” and “secondary” seals are effected by use of first and second seal rings  21 ,  22 . As closure  14  is torqued about axis  11 , both seal rings  21 ,  22  are splayed and compressed relative to upwardly facing surface  23  on annular rim  24  of container neck  16 .