Patent Publication Number: US-6702161-B2

Title: Closure having rotatable spout and axially movable stem

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a Continuation-in-Part of U.S. patent application Ser. No. 10/017,187 filed Dec. 12, 2001, entitled CLOSURE HAVING ROTATABLE SPOUT AND AXIALLY MOVABLE STEM, the entire contents of which is incorporated herein by this reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a new and improved closure for a container. More particularly, the present invention is directed to a closure for a container having an opening sealed by a sheet member such as a foil or membrane seal. 
     2. Description of Related Art 
     Bottled beverages have long been a staple in the American household. In recent years, bottled water, sport drinks and other bottled beverages have increased in popularity. In fact, according to The Bottled Water Web™, bottled water sales alone reached $1.4 billion in 1999 and are expected to grow at a compound annual rate of about 15% over the next five years. 
     Bottled water, sport drinks and other bottled beverages are often packaged in a container having a push-pull resealable closure spout. An exemplar closure having a resealable bottle cap with a push-pull spout is U.S. Pat. No. 5,465,876 to Crisci. These caps are generally characterized by having an orificed spout slidably moveable on a cylindrical tube. The tube has a plug at an open end. Linear motion of the spout relative to the tube alternatively causes the plug to seal or unseal the spout orifice. Effective sealing is achieved through interference of the plug with the internal diameter of the orifice. However, increasing this interference to improve sealing may lead to excessive opening and closing forces, since the linear motion involved limits mechanical advantage. 
     Often, known containers used in combination with the closures of the type disclosed by the Crisci &#39;876 patent include a foil or membrane seal to preserve freshness and otherwise prevent tampering with the contents of the container. Disadvantageously, a consumer must unscrew or otherwise remove the closure from the container, remove the foil or membrane seal and screw the closure back onto the container. Only then may the consumer access the contents of the container through the push-pull closure. 
     One known container/closure combination which allows a consumer to cut through a lid without removing the closure from the container is disclosed by U.S. Pat. No. 4,690,304 to Morel. The Morel &#39;304 patent discloses an obturating device for tubes, flasks and other containers, the opening and closing of which are controlled through rotation. Disadvantageously, the device disclosed by the Morel &#39;304 patent has a complex structure and is not designed for conventional containers for bottled beverages. 
     Yet another known container/closure combination is disclosed by U.S. Pat. No. 5,938,086 to Gross. The Gross &#39;085 patent discloses a container and closure with a non-rising rotatable housing, dispensing valve, and separate releasable internal shipping seal. Similar to the Morel device, the closure disclosed by the Gross &#39;085 patent is controlled through rotation. Disadvantageously, the closure disclosed by the Gross &#39;085 patent also has a complex structure and is not designed for conventional containers for bottled beverages. 
     What is needed is a closure for a container which overcomes the above and other disadvantages of known closures 
     BRIEF SUMMARY OF THE INVENTION 
     In summary, one aspect of the present invention is directed to a closure for a container having a foil or membrane sealed opening. The closure includes a cap, a spout and a stem. The cap includes a cap top, a cap skirt depending from the cap top, an open sleeve and a stem guide. The cap skirt has an inwardly extending thread adapted to detachably engage the container. The open sleeve extends upwardly from the cap top. The stem guide extends along an internal surface of the sleeve. The spout rotatably engages the sleeve and includes a spout top having a central aperture, an outer spout skirt and an inner skirt. The outer skirt depends from the spout top radially outward of the sleeve and rotatably engages the sleeve. The inner spout skirt depends from the spout top radially within the sleeve. The stem includes a substantially cylindrical body positioned radially within the inner spout skirt, a plug for selectively sealing the central aperture, an outwardly extending spout-engaging thread, and an outwardly extending cap-engaging member. The spout engaging member engages the inner spout skirt such that the stem is adapted for helical motion with respect to the spout. The cap-engaging member engages the stem guide such that the stem is adapted for axial motion with respect to the cap upon rotation of the spout. 
     The stem guide of the cap comprises structure to restrict relative rotation between the cap and stem. In one embodiment, the stem guide of the cap includes a substantially vertically extending groove and the cap-engaging member of the stem includes a tab received in the groove. 
     In one embodiment the stem includes a downwardly extending piercing member adapted for piercing the foil or membrane of the container upon rotation of the spout relative to the cap. 
     Optionally, the cap includes a tamper-evident band frangibly connected to a bottom portion of the cap skirt that is adapted to detachably engage the container. 
     Optionally, the cap includes a rotation stop limiting rotation of the spout relative to the cap. 
     Optionally, the spout and/or stem includes structure to limit relative rotation between the spout and stem. 
     Optionally, the spout top includes a non-cylindrical outer wall that forms a gripping portion that facilitates gripping and rotation of the spout by a user. 
     Optionally, one of the cap and spout includes a tamper stop and the other of the cap and spout includes a removable tamper tab engaging the tamper stop, the tamper tab engaging the tamper stop and preventing substantial rotation of the spout relative to the cap until the tamper tab is removed. 
     In one embodiment, the sealing member includes an upper member and a lower member which encase a consumable material. The consumable material may be a tablet. The piercing structure may be adapted for piercing the sealing member and biasing the upper and lower members downwardly to facilitate the introduction of the tablet into the container upon rotation of the spout relative to the cap. 
     In one embodiment, the foil member includes an upper foil member and a lower foil member which encase a consumable material. The consumable material may be a tablet. The piercing structure may be adapted for piercing the sealing member and biasing the upper and lower members downwardly to facilitate the introduction of the tablet into the container upon rotation of the spout relative to the cap. 
     An object of the present invention is to provide a container closure having a rotatable spout and an axially movable stem for facilitating opening and closure of bottled substances. 
     Another object of the present invention is to provide a closure for a resealable container having a foil or membrane sealed opening. 
     Yet another object of the present invention is to provide a closure for a bottled substance having a foil or membrane sealed opening that is capable of opening the sealed opening without first removing the closure from the container. 
     Yet another object of the present invention is to permit increased interferences between sealing members by employing the mechanical advantage offered by helical structure in bringing dimensionally interfering surfaces into position. 
     The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective cross-sectional view of a closure for a foil or membrane sealed container in accordance with the present invention showing a cap, a spout, and a stem of the closure with the stem in an initial closed position. 
     FIG. 2 is perspective cross-sectional view of the closure of FIG. 1 showing the stem of the closure in an opened position. 
     FIG. 3 is an exploded view of the closure of FIG. 1 with the a cross-sectional view of the cap and spout taken along line  3 — 3  of FIG. 1 and a side elevational view of the stem. 
     FIG. 4 is a perspective view of the closure spout of FIG.  1 . 
     FIG. 5 is a perspective view of the stem of FIG.  1 . 
     FIG. 6 is a perspective view of the cap of FIG.  1 . 
     FIG. 7 is a bottom plan view of the spout of FIG.  1 . 
     FIG. 8 is a perspective cross-sectional view of a modified closure for a membrane sealed container in accordance with the present invention similar to that shown in FIG. 1 with a modified stem in an opened position. 
     FIG. 9 is an enlarged perspective view of the stem shown in FIG.  8 . 
     FIG. 10 is a perspective cross-sectional view of a modified closure for a membrane sealed container in accordance with the present invention similar to that shown in FIG. 1 with a modified stem in an initial closed position. 
     FIG. 11 is a perspective cross-sectional view of the closure of FIG. 10 showing the stem of the closure in an opened position. 
     FIG. 12 is a perspective cross-sectional view of a modified closure for a membrane sealed container in accordance with the present invention similar to that shown in FIG. 1 with a modified cap. 
     FIG. 13 is a perspective view of the cap of FIG.  12 . 
     FIG. 14 is a top plane view of the cap of FIG. 12 showing a cross-sectioned portion of the stem of FIG. 12 in phantom. 
     FIG. 15 is a perspective cross-sectional view of another modified closure for a foil or membrane sealed container in accordance with the present invention similar to that shown in FIG. 1 with a modified stem and foil configuration in an initial closed position. 
     FIG. 16 is perspective cross-sectional view of the closure of FIG. 15 showing the stem and foil configuration in an opened position. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to those embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. 
     A closure  30  in accordance with the present invention is shown in FIG.  1 . The illustrated closure can be used with a container of the type often used for bottled water, sport drinks and other flowable bottled substances. The closure of the present invention is particularly suited for use with containers having an opening that is sealed by a foil or membrane seal. The closure of the present invention generally includes a cap  31  adapted for releasably engaging the container, a spout  32  rotatably mounted on cap  31 , and a stem  36  axially mounted on cap  31  and positioned within spout  32 . Each of cap  31 , spout  32  and stem  36  may advantageously be formed as monolithic thermoplastic members using, for example, injection molding techniques well known in the art. 
     In the illustrated embodiment, cap  31  is generally dimensioned and configured to cooperate with a container having a tamper-evident neck finish of the type shown in U.S. Pat. No. 6,112,923 to Ma, the entire contents of which are incorporated herein by this reference. One should appreciate, however, that cap  31  can be adapted to cooperate with other container neck finishes within the scope of the present invention. For example, a cap in accordance with the present invention can be adapted to cooperate with a container having a snap-on, screw-off cap neck finish of the type shown in U.S. Pat. No. 6,173,853 to Luch, the entire contents of which are incorporated herein by this reference. Alternatively, other cooperative closure-container retention structure, such as a simple snap engagement, can also be employed in accordance with the present invention. 
     Cap  31  includes a generally annular cap top  37 . Although the illustrated cap top  37  is planar, the cap top can alternatively have a frustoconical or other suitable shape. A cap skirt  38  depends downwardly from cap top  37  in a well known manner. Cap skirt  38  includes vertically extending ribs  41  extending from an external surface thereof to provide a gripping surface for facilitating a user in gripping and turning cap  31 . Cap skirt  38  also includes a container-engaging member extending from an internal surface of the cap skirt. In the illustrated embodiment, the container-engaging member includes two internal threads  42 . As noted above, the cap can be adapted for use with various container neck finishes in which case a different thread or snap fit configuration can be used. Preferably, a tamper-evident band  43  is frangibly connected to a bottom portion of cap skirt  38  and is adapted to detachably engage the container in a well known manner, as described in the &#39;923 patent to Ma. 
     A substantially cylindrical open sleeve  47  extends upwardly from a central portion of cap top  37 . The illustrated sleeve is concentric with a central axis of cap  31 , however, one should appreciate that the sleeve can be offset to one side of the cap. An outwardly extending bead  48  extends outwardly from an upper portion of sleeve  47  and provides a downward facing shoulder  49 , as most clearly shown in FIGS. 3 and 6, that is rotatably engagable with spout  32 . Although bead  48  is adjacent the upper edge of sleeve  47 , the bead can be positioned anywhere along the sleeve provided it has a downward facing shoulder  49  formed to be rotatably engagable with the spout. 
     Cap sleeve  47  further includes a stem guide  52  for engaging stem  36  and guiding the stem for axial motion within spout  32 . Stem guide  52  extends radially inward and along an internal surface of sleeve  47 . The illustrated embodiment includes substantially vertically extending stem guide  52  in the form of two diametrically opposed grooves  53 . One should appreciate that one, two or more grooves can be used in accordance with the present invention as such grooves need only to prevent relative rotation of the stem relative to the cap, as will become evident below. 
     Spout  32  is rotatably mounted on sleeve  47  of cap  31 . Spout  32  includes a spout top  54  having a central aperture  58  through which the contents of the container can be dispensed. A cylindrical outer spout skirt  59  depends from spout top  54  and is located radially outward of sleeve  47 . Outer spout skirt  59  includes an inwardly extending circumferential bead  60  which cooperates with outwardly extending bead  48  of sleeve  47  to limit axial displacement while allowing rotation of spout  32  relative to cap  31 . Alternatively, the outer spout skirt can be provided with a bead, and the sleeve with a circumferential groove, or the sleeve with a bead and the spout with a groove, in order to provide a suitable rotory connection between the spout and the cap. One should appreciate that either one or both of the bead and the groove can be segmented provided the configuration allows for circumferential motion there between. Preferably, the cooperating beads  48  and  60  are diametrically interfering to provide a liquid tight seal between the inner surface of outer spout skirt  59  and sleeve  47 . However, if the bottled contents are flowable granular solid, this seal requirement between spout and sleeve can be relaxed and need not be liquid tight. 
     Spout  32  further includes an inner spout skirt  63  depending from spout top  54 . Inner spout skirt  63  is positioned radially within both outer spout skirt  59  and sleeve  47 . Internally extending helical guides  64  extend from an inner surface of inner spout skirt  63  which cooperate with stem  36 , as discussed below. 
     Stem  36  is positioned radially within sleeve  47  and inner spout skirt  63  and stem  36  is axially slidable from an initial closed position, as shown in FIG. 1, to an open position, as shown in FIG.  2 . In the embodiments of FIGS. 1-6, stem  36  includes a substantially cylindrical body  65  and an upwardly projecting plug  69 . Although the illustrated plug is cylindrical, one should appreciate that the plug need not be cylindrical provided it has a shape that is complementary to the shape of the central aperture. For example, the plug and the aperture may have a complementary frustoconical, oval, polygonal, or other suitable shape. In the illustrated embodiment, three webs  70  rigidly interconnect cylindrical body  65  and plug  69  in such a manner that allows the contents of the container to pass through stem  36  and to central aperture  58  of spout  32 . One should appreciate that one or more webs can be used in accordance with the present invention. One should also appreciate that the stem need not be cylindrical in shape. The only requirements for the stem are that the stem is able to seal orifice  58  in a first stem position and stem allows bottled contents to flow to the orifice in a second open stem position. For example, the stem can be a solid member having one or more passageways therethrough allowing the contents of the container to pass through or around the stem. Alternatively, the stem can be a cross-shaped structure as embodied in FIGS. 10 and 11, as discussed below. 
     Stem  36  includes an outwardly extending cap-engaging member  71  that engages stem guide  52  and allows axial motion of stem  36  with respect to sleeve  47 . In the illustrated embodiment, cap-engaging member  71  is in the form of a pair of outwardly extending anti-rotation tabs  74  and  75 . Each tab  74  and  75  is received in a respective one of the diametrically opposed grooves  53  located on an internal surface of sleeve  47 . Preferably, tabs  74  and  75  extend upwardly between the inner surface of sleeve  47  and inner spout skirt  63  to provide stem  36  with increased structural integrity and minimize the possibility of tilting the plug out of alignment with the central aperture. 
     One should appreciate that one, two or more circumferentially spaced tabs can be used in accordance with the present invention provided each tab cooperates with a corresponding groove and prevents relative rotation of stem  36  relative to cap  31 . One should also appreciate that other configurations can be used in accordance with the present invention. For example, the stem can include pairs of outwardly extending splines forming a groove which, in turn, cooperates with a corresponding internal spline located on the internal surface of the cap sleeve. 
     Stem  36  further includes an outwardly extending spout-engaging member which is configured to allow helical motion between stem  36  and spout  32 . In particular, an external helical thread  80  extends outwardly from an external surface of cylindrical body  65  and cooperate with the helical guides  64  of inner spout skirt  63 . One should appreciate that other types of spout-engaging members can be used within the scope of the present invention. For example, one or more outwardly extending pins or other protrusions can extend from the external surface of the cylindrical body and cooperate with helical grooves formed in the internal surface of the inner spout skirt. Alternatively, inwardly extending pins or other protrusions can extend from the internal surface of the inner spout skirt and cooperate with helical grooves formed in the external surface of the cylindrical body. 
     As noted above, the closure of the present invention is particularly suited for use with containers having an opening that is initially sealed by a foil or membrane seal. A foil or membrane seal  81  is schematically shown in FIG.  1  and positioned immediately below top  37  of cap  31 . Seal  81  is conventionally affixed to seal the opening of a container in a well known manner. In one form of processing, a foil is first inserted into the closure at the closure manufacturing facility and is conveyed with the closure to the bottling line. After application of the closure to the container, the foil is heat sealed to the bottle by well-known methods such as induction heating. In another form of processing, a foil or membrane is first adhered to the mouth of a filled container by well known method such as conductive heating, induction heating or adhesive attachment. The closure is then subsequently applied to the sealed container. 
     In use, such a foil or membrane seal must be pierced, torn, ruptured or otherwise damaged in order to gain access to the contents of the container. In this regard, stem  36  is provided with a downwardly extending piercing structure  82 . Preferably, piercing structure  82  is a downwardly extending portion of one or more of the tabs, for example, tab  75 , and includes a wedge portion  85 . Stem, piercing structure, tab and wedge are all preferably monolithically formed as a one-piece member, although they also can be formed as a plurality of members which are secured together as a unit. 
     As stem  36  is axially slid from the initial closed position shown in FIG. 1 to the open position shown in FIG. 2, piercing structure  82  pierces into foil or membrane seal member  81  and cuts a flap  86  in member  81 . Wedge portion  85  pushes flap  86  away from the remainder of seal  81 , as shown in FIG. 2, thus allowing the contents of the container to dispense through closure  30 . As shown in FIG. 2, flap  86  remains attached to member  81  thus minimizing the chance that flap  86  could fall into the contents of the container and/or be dispensed through or clog the central aperture. 
     In one embodiment of the present invention, closure  30  further includes a rotation stop limiting rotation of spout  32  relative to cap  31 . As shown in FIG. 1, a pair of diametrically opposed rotation stops  87  extend upwardly from cap top  37  and cooperate with an pair of internal splines  91  extending inwardly from an internal surface of a lower cylindrical outer wall  92  of spout  32 . This configuration limits rotation of spout  32  relative to cap  31  to approximately 180°. One should appreciate that the actual range of rotation between the spout and cap can be varied and the stops can be positioned accordingly. In particular, the stops can be modified to limit rotation to a larger or smaller angle to correspond with the pitch of the threaded connection between the stem and the spout. For example, in the event that the pitch is double that of the illustrated embodiment, the stops can be modified to limit relative rotation between the spout and cap to 90° because such rotation still produces the same amount of axial motion of the stem with respect to the cap. 
     Other structure can be utilized to for limiting relative rotation between stem  36  and spout  32  in accordance with the present invention. For example, because relative rotation between stem  36  and sleeve  47  is prohibited, placing a barrier at the top end of helical thread  80  would serve to prevent axial motion of the stem past its full-open position, as shown in FIGS. 8 and 9 and discussed below. 
     In one embodiment of the present invention, spout  32  includes an substantially oval-shaped outer wall  93  of spout skirt  59 , as best seen in FIG.  4 . Upper outer wall  93  forms a convenient gripping portion on spout  32  which facilitates a user in gripping and rotating spout  32  relative to both cap  31  and the container. One should also appreciate that the spout can be round instead of oval and can include ribs to facilitate a user gripping the spout. 
     In one embodiment of the present invention, a tamper-evident stop  96  is provided on cap top  37 . A removable tamper-evident tab  97  is provided on spout  32 . Tamper-evident tap  97  is frangibly connected to an outer surface of the lower outer wall  92  and initially engages tamper stop  96  such that spout  32  cannot be rotated relative to cap  31  until tamper-evident tab  97  is removed. One should appreciate that other suitable tamper-evidencing means can be used to initially limit rotation between the spout and the cap. 
     In operation and use, once the closure and corresponding foil or membrane sealed container are in the hands of a consumer or user, the user can be assured that closure  31  has not violated seal  81  provided tamper evident tab  97  and tamper-evident band  43  remain undamaged and intact. 
     In order to dispense the contents of the container, the user grips and pulls tamper-evident tab  97  and tears it away from spout  32 . The user then grips spout  32  and rotates it clockwise with respect to cap  31  which, through the helical cooperation of helical guides  64  of spout  32  and helical thread  80  of stem  36 , slides stem  36  downwardly from the initial closed position shown in FIG. 1 toward the open position shown in FIG.  2 . In the illustrated embodiment, external helical thread  80  of stem  36  is opposite that of closure-engaging thread  42  of cap  31  whereby twisting spout  32  cannot inadvertently loosen cap  31  with respect to the container. As stem  36  slides downwardly, piercing structure  82  of stem  36  contacts and pierces foil or membrane seal  81  and plug  69  moves away from central aperture  58 , thus providing passageway through which the contents of the container can pass through closure  30 . Continued downward motion of stem  36  causes wedge portion  85  of stem  36  to fold flap  86  away from the remainder of seal  81  to provide a significant unobstructed opening in seal  81  through which the container contents can pass. 
     Once the user has dispensed some or all of the contents of the container, the user can rotate spout  32  counterclockwise with respect to cap  31  in order to close and fluidly seal closure  30 . In particular, as the user rotates spout  32 , stem  36  axially slides upwardly from the open position shown in FIG.  2  and returns to the closed position shown in FIG.  1 . Plug  69  enters central aperture  58  and fluidly seals the closure and container. 
     The closure of the present invention advantageously provides a convenient means for a user to open a foil or membrane sealed beverage container with a mere twist of a spout. The closure of the present invention eliminates the need for the consumer to remove the closure from the container in order to puncture, tear and/or remove the foil or membrane seal from the container. 
     The closure of the present invention advantageously also provides a convenient means to reseal the container with a mere twist of a spout. In this regard, the closure of the present invention permits improved reseal characteristics compared to current “push-pull” closures. This is a result of the ability to increase sealing interferences between the plug  69  and the central aperture  58 . This is a direct result of using rotational motion of the spout to accomplish axial movement of the stem. The increased mechanical advantage produced by the rotational motion allows interferences to be increase without opening and closing forces becoming excessive. 
     FIGS. 8 and 9 show another embodiment in accordance with the present invention having a closure  30   a . Like reference numerals have been used to describe like components of closures  30  and  30   a . Stem  36   a  is substantially the same as stem  36  of the previous figures but includes a barrier  102  at the top end of helical thread  80   a  to prevent axial motion of stem  36   a  past its full-open position, as shown in FIG.  8 . In this embodiment, barrier  102  limits the range of rotation between spout  32   a  and stem  36   a . As relative rotation between cap  31   a  and stem  36   a  is limited because anti-rotation tabs  74   a  and  75   a  of stem  36   a  are received within opposed grooves  53   a  of cap  31   a , the range of rotation between spout  32   a  and cap  31   a  is also limited by barrier  102 . Accordingly, rotation stops are not necessary to limit the range rotation between spout  32   a  and cap  31   a  and are not provided in this embodiment. 
     FIGS. 10 and 11 show another embodiment in accordance with the present invention having a closure  30   b . Like reference numerals have been used to describe like components of closures  30   b ,  30   a  and  30 . Cap  31   b  and spout  32   b  are substantially the same as cap  31  and spout  32 . Stem  36   b , however, includes a cross-shaped structure having four substantially planar vanes  103  that are perpendicularly disposed with respect to one another. Advantageously, stem  36   b  provides a simple configuration that is easier to manufacture. 
     Stem  36   b  includes an outwardly extending spout-engaging member which is configured to allow helical motion between stem  36   b  and spout  32   b . In particular, an external projection  104  extends outwardly from each vane  103  of stem  36   b  and cooperates with helical guides  64   b  of inner spout skirt  63   b . One should appreciate that one, two, three or four vanes can be provided with a projection which cooperates with one or more helical grooves formed in the internal surface of the inner spout skirt. 
     A foil or membrane seal  81   b  is schematically shown in FIG.  10  and positioned immediately below top  37   b  of cap  31   b . Stem  36   b  is provided with a downwardly extending piercing structure  82   b . In the illustrated embodiment, piercing structure  82   b  is a downwardly extending portion of one or more of the tabs, for example, tab  75   b , and includes a wedge portion. As stem  36   b  is axially slid from the initial closed position shown in FIG. 10 to the open position shown in FIG. 11, piercing structure  82   b  pierces into foil or membrane seal member  81   b  and cuts a flap  86   b  in member  81   b  in the same manner as piercing structure  82  discussed above. 
     Although the illustrated stem  36   b  includes four vanes, one should appreciate that the number of vanes can vary. For example, three, four or more vanes can be used in accordance with the present invention provided that one or more vanes includes structure to cooperate with the axial guide of the cap and one or more vanes includes structure to cooperate with the helical guides of the spout. 
     FIGS. 12-14 show another embodiment in accordance with the present invention having a closure  30   c . Like reference numerals have been used to describe like components of closures  30   c ,  30   b ,  30   a  and  30 . Spout  32   c  and stem  36   c  are substantially the same as spout  32   b  and stem  36   b . Sleeve  37   c  of cap  31   c  includes a pair of offset stem guides  52   c , each having a single vertically extending protrusion or spline  107 . In contrast to the above embodiment shown in FIGS. 10 and 11 in which anti-rotation tabs  74   b  and  75   b  are received in stem groove  53   b  to prevent rotation of stem vanes  103  with respect to cap  31   b , anti-rotation tabs  74   c  and  75   c , which are dimensioned and configured to interfere with offset splines  107 , prevent rotation of stem vanes  103   c  with respect to cap  31   c , as can be seen in FIG.  14 . Advantageously, cap  31   c  provides a simple configuration that is easier to manufacture. 
     A foil or membrane seal  81   c  is schematically shown in FIG.  12  and positioned immediately below top  37   c  of cap  31   c . Stem  36   c  is provided with a downwardly extending piercing structure  82   c . In the illustrated embodiment, piercing structure  82   c  is a downwardly extending portion of one or more of the tabs, for example, tab  75   c , and includes a wedge portion. As stem  36   c  is axially slid from the initial closed position shown in FIG. 12 to an open position, piercing structure  82   c  pierces into foil or membrane seal member  81   c  and cuts a flap in member  81   c  in the same manner as piercing structure  82   b  discussed above. 
     FIGS. 15 and 16 show another embodiment in accordance with the present invention having a closure  30   d . Like reference numerals have been used to describe like components of closures  30 ,  30   a ,  30   b ,  30   c  and  30   d . Closure  30   d  is substantially the same as closure  30  of the previous figures but includes double-lined seal  81   d  containing a consumable  109  that may be mixed with, or otherwise introduced to, the contents of the container to which closure  30   d  is mounted when closure  30   d  is initially opened. 
     In the illustrated embodiment, consumable  109  is in the form of a tablet, however, one should appreciate that other consumables including, but not limited to, liquids, powders, and other solids, may be utilized in accordance with the present invention. One should appreciate that the consumable material to be added may be used to produce a beverage or other liquid that is a suspension or a solution. Furthermore, the consumable material may include an effervescing agent. 
     As shown in FIG. 15, consumable  109  is initially isolated from the contents of the container upon which closure  30   d  is mounted. In particular, seal  81   d  is a double-lined foil seal that includes an upper foil member  111  and a lower foil member  112  between which consumable  109  is encased. 
     In operation and use, consumable  109  is encased within seal  81   d  and thus remains isolated from the contents of the container. Once the consumer wishes to dispense the contents of the container, the user grips spout  32   d  and rotates it clockwise with respect to cap  31   d  which, through the helical cooperation of helical guides  64   d  of spout  32   d  and helical thread  80   d  of stem  36   d , slides stem  36   d  downwardly from the initial closed position shown in FIG. 15 toward the open position shown in FIG.  16 . As stem  36   d  slides downwardly, piercing structure  82   d  of stem  36   d  contacts and pierces both upper and lower foil members  111  and  112  of seal  81   d  to facilitate the introduction of consumable  109  to the contents of the container. Continued downward motion of stem  36   d  causes wedge portion  85   d  of stem  36   d  to fold flap  86   d  away from the remainder of seal  81   d  thus allowing consumable to fall from seal  81   d  into the contents of the container, thus allowing the consumable to dissolve or otherwise mix with the contents of the container. 
     Once the user has dispensed some or all of the mixed contents of the container, the user can rotate spout  32   d  counterclockwise with respect to cap  31   d  in order to close and fluidly seal closure  30   d . In particular, as the user rotates spout  32   d , stem  36   d  axially slides upwardly from the open position shown in FIG.  16  and returns to the closed position shown in FIG.  15 . Plug  69   d  enters central aperture  58   d  and fluidly seals the closure and container. 
     The closure of the present invention advantageously provides a convenient means to separately store the components of a beverage until a consumer is ready to consume the beverage. Namely, closure  30   d  provides a convenient means for a user to open a foil or membrane sealed beverage and to introduce a mixable consumable into the container with a mere twist of a spout. The closure of the present invention eliminates the need for the consumer to remove the closure from the container in order to puncture, tear and/or remove the foil or membrane seal from the container in order to mix the components of the beverage. 
     In many respects the modifications of the various figures resemble those of preceding modifications and the same reference numerals followed by subscripts “a”, “b”, “c” and “d” designate corresponding parts. 
     The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.