Abstract:
Resealable beverage containers include caps that are twisted to impart translational motion of the cap to push a tear panel into the container. Cam elements are used to convert rotational movement to translational movement. The caps are preferably made of molded plastic material, and include cam elements formed on the sidewalls of the caps that engage cam followers or projections formed on the inner cylindrical surface of a socket which is formed in the lid of the beverage container. Methods of manufacturing resealable beverage containers avoid the need to form rivets and to attach pull tabs, thus saving costs and making the beverage containers more easily recycled.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application does not claim the benefit of any provisional or previously filed U.S. or foreign applications. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to resealable beverage containers and methods of making same. In particular, and according to one aspect of the invention, a beverage container such as an aluminum can is provided with a cap that is twisted by the consumer to open the can. The twist or rotational movement of the cap is converted into linear motion by a cam mechanism to drive the cap into opening action, whereby a frangible sealing tab is pushed into the can. Once the can is opened, the cap can be reverse-twisted to remove it from the opening, and then after drinking, the consumer can twist the cap back into a sealing position within the opening. 
         [0004]    2. Description of the Related Art 
         [0005]    The beverage and can industries have long sought to create a can that is both economical to produce and convenient for use by consumers. In the past, beverage cans were provided with a “pull tab” which the consumer would grab by a ring, and pull until the tab was removed from the can. This created a problem in that the tab became disposable waste for which the consumer was responsible to ensure proper disposal. Often the consumer failed to properly dispose of the tab, thereby creating not only litter, but also a safety issue, in that the tabs could be swallowed by small children. Moreover, the edges of the pull tab were sharp enough that they could, if mishandled, cut the fingers or hands of the consumer or anyone else who handled a loose pull tab. As a result of these problems, the industry moved in the direction of a tab that stayed on the can after opening, thereby preventing both litter and any sharp edges from coming into contact with consumers. 
         [0006]    The present state of the art is to have a “stay on” tab that is attached to the can lid by a rivet formed in the can lid next to the opening. The opening is formed by a score line, or frangible “kiss cut” which breaks when the tab is pulled up by the consumer. The score line, when broken, produces a hinged flap that stays connected to the can lid, but inside the can. 
         [0007]    Beverage cans with stay on tabs suffer from at least the following deficiencies. First, they are not resealable, so that once the consumer opens the beverage, the contents are subject to loss of carbonation, and the influx of foreign material due to the contents being open to the surrounding environment. Secondly, in order to form the rivet which is used to secure the stay on tab to the beverage lid, the lid needs to be made of a different material, typically an aluminum alloy that is stronger than the aluminum alloy used to make the sides and bottom of the can. Further, the tab itself is typically made of a different alloy than the sides and lid, reflecting the need for a still stronger, typically heavier material. As a result, recycling of the aluminum beverage can is problematic because the different materials need to be separated. The use of three different materials also tends to add weight, and expense, to the finished container. 
         [0008]    A need exists for improved beverage containers that are resealable, cost effective to produce, and “green” in terms of avoiding waste and facilitating the recycling of aluminum cans. Concurrently, a need exists for improved methods for manufacturing beverage containers that result in faster production time, lower production costs, and improved products. 
       SUMMARY OF THE INVENTION 
       [0009]    A beverage can has a sidewall and integrally formed bottom. A top lid includes a socket integrally formed therein which includes a substantially cylindrical sidewall and a bottom wall. A score line formed in the bottom wall defines tab which forms an opening into the can when the score line is broken. A cap is fitted in the socket and has a sidewall which is formed with cam surfaces. The cam surfaces cooperate with detents formed in the cylindrical sidewall of the socket, so that when the cap is twisted or rotated through a sufficient number of radians, or angle of motion, the cam surfaces translate rotational motion into linear motion, driving the cap downwardly into the socket. As the cap moves downwardly, a protrusion formed on the lower surface of the cap impinges on the periphery of the score line, thereby pushing the tab into the can. 
         [0010]    Once opened, the cap can be discarded if the entire contents of the can are consumed. Alternatively, the cap can be re-fitted into the socket, so that the cam surfaces engage the detents, and rotated to achieve a sealing position, whereby the contents of the can are protected from the ambient atmosphere. This will result in the prevention of spillage, the loss of carbonation, and the prevention of foreign objects from entering the can. 
         [0011]    Preferably, the beverage container is a “can,” but the same principals described above could be used for other types of beverage containers, including bottles made of various materials, including plastic, paper, metal (such as aluminum), cartons, cups, glasses, etc. In one particularly preferred embodiment, the beverage container is an aluminum can, and lid is made of the same aluminum alloy material as the sidewall of the can. The cap is preferably made of plastic material of sufficient hardness that the cam surfaces do not deform during opening and closing operations. 
         [0012]    The cap may be a separate implement, sold separately from the beverage container, and re-used after washing. Also, caps with different features may be provided, such as a cap that has a child&#39;s sip cup top, so that the beverage can be converted into a child&#39;s sip cup. Other implements can be envisioned, including a cap that has a baby bottle “nipple” formation to convert the beverage can into a baby bottle. In such an embodiment, the contents of the beverage can could be infant formula. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The details of the present invention, both as to its structure and operation, can best be understood by referring to the accompanying drawings, in which like reference numbers and designations refer to like elements. 
           [0014]      FIG. 1  is a side elevation view showing an example of a beverage container according to the present invention; 
           [0015]      FIG. 2  is a side elevation view, similar to  FIG. 1 , but exploded to reveal the cap and socket features of the beverage container; 
           [0016]      FIG. 3  is a side elevation view, similar to  FIGS. 1 and 2 , but further exploded to reveal the lid of the beverage container; 
           [0017]      FIG. 4  is an exploded, bottom elevation view of the beverage container of  FIGS. 1-3 ; 
           [0018]      FIG. 5  is an enlarged, bottom elevation and exploded view of the lid and cap of the beverage container of  FIGS. 1-4 ; 
           [0019]      FIG. 6  is an enlarged, top side elevation view of the cap used in the previous figures; 
           [0020]      FIG. 7  is an enlarged, bottom side elevation view of the cap used in the previous figures; 
           [0021]      FIG. 8  is a top view of the beverage container of the previous figures, showing the cap in a pre-opened position; 
           [0022]      FIG. 9  is a top view of the beverage container of  FIG. 8 , with the cap removed, showing the projections inside the socket for engaging cam surfaces; 
           [0023]      FIG. 10  is a side elevation view of the cap, enlarged to show the cam surfaces on the cylindrical sidewall of the cap; 
           [0024]      FIG. 11  is a side elevation view of the cap of  FIG. 10 , rotated 90 degrees; 
           [0025]      FIG. 12  is a top elevation view, showing the top of the beverage container, or lid, with the cap removed to expose features of the socket; 
           [0026]      FIGS. 13A through 13D  show cross sectional views of the cap moving sequentially between opening and resealing positions; 
           [0027]      FIG. 14  is a flow chart showing manufacturing steps according to one aspect of the present invention; and 
           [0028]      FIG. 15  is a flow chart showing manufacturing steps according to another aspect of the present invention. 
           [0029]      FIG. 16  is a partial cutaway, partial section of the beverage container of the previous drawings. 
           [0030]      FIG. 17  is the same view as  FIG. 16 , but from a different point of view. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]    Referring to  FIGS. 1 through 12 , a beverage container  10  includes a cylindrical sidewall  12 , a closed bottom wall  14 , integrally formed with the sidewall  12  and a lid  16  connected to the sidewall  12  at the end opposite the bottom wall  14 . In the illustrated embodiment, the beverage container is a can, wherein the bottom wall  14  and the sidewall  12  are formed from a single piece of aluminum material, using otherwise known processes. The aluminum material is a light weight aluminum alloy commonly used in the beverage can industry. The lid  16  is preferably made of the same light weight aluminum alloy material, and is joined at the upper end of the sidewall through likewise known processes. The lid  16  includes a cylindrical socket  18  which extends downwardly into the beverage container  10  from an upper wall  17 . The socket  18  is formed near a peripheral edge or lip of the lid  16  as is customary in the art, to allow drinking from the beverage container  10 . A cap  20  fits into the socket  18  and engages same in a manner described in more detail below. The cylindrical sidewall  12  of the beverage container  10  is preferably tapered at both the upper and lower ends to provide greater structural integrity, particularly for use with pressurized contents, such as when used for carbonated beverages. 
         [0032]    The lid  16  has an outer perimeter that is connected to the upper open end of the sidewall  12  of the beverage container, using known processes, to form an enclosure which contains a beverage. Beverages contained therein are not limited, but include carbonated or non-carbonated beverages, and could also include foodstuffs, and non-edible products. The socket  18  is integrally formed in the upper wall  17  of the lid  16  and includes a cylindrical sidewall  22 , which extends downwardly into the beverage container  10 , and a bottom wall  24 . A score line  26  is formed in the bottom wall  24  in order to create a flap or tear panel  25  (see  FIGS. 13B ,  13 C and  13 D) which is pushed into the can when the can is opened. In the opened position, the tear panel  25  remains connected to the bottom wall  24  due to the fact that the score line  26  does not make a complete circle or loop; a hinge  28  is created where the bottom wall  24  is not scored (see  FIG. 5 ). 
         [0033]    As seen in figures, the cap  20  is sized to fit substantially within the socket  18 , and includes a flat annular surface  21  which is disposed between the cam shaped bottom surface  38  and the cap&#39;s cylindrical sidewall  40 . In  FIG. 9 , the bottom wall  24  of the socket  18  may include a flat annular surface  27  which is disposed between the socket sidewall  22  and the circular score line  26 . When assembled and in the “resealed” position shown in  FIG. 13D , the flat annular surface  21  of the cap  20  comes into contact with the annular surface  27  of the bottom of the socket  18  to effectively reseal the container  10 . 
         [0034]    The lid  16  has a shallow, elongated U-shaped depression  30  which serves two purposes. First, the depression  30  acts as a stiffening structure to provide greater strength to the lid  16 . This is particularly advantageous if the lid  16  is to be made of the same aluminum alloy as the sidewall  12  and bottom wall  14  of the container  10 . Secondarily, the depression  30  adds a familiar look to consumers who are accustomed to the prior art beverage containers employing a pull tab that is operated first in an opening direction, and then secondly, in a seated direction, where the hinged pull tab is positioned after opening. 
         [0035]    As seen in  FIGS. 2 ,  3  and  5 , the cylindrical sidewall  22  of the socket  18  has a plurality of equally spaced protrusions  32 , disposed substantially on the same plane and being integrally formed in the sidewall  22 .  FIG. 5  shows one protrusion as an indentation or recess, since  FIG. 5  shows the outer cylindrical sidewall of the socket  16 , whereas the other Figures show the inner cylindrical sidewall  22  of the socket  16 . The protrusions  32  cooperate with the cap  20  in a manner described below in order to open and reseal the container  10 . 
         [0036]    Referring to  FIGS. 5-7 , the cap  20  has an upper, radially extending skirt  34  which acts as a tamper proof indicator. As seen in  FIG. 1 , prior to opening the beverage container  10 , the skirt  34  seats flush with the flat outer surface  36  of the lid  16 . The skirt is integrally formed with the cap  20 , which is preferably made of plastic material. The skirt  34  includes a series of frangible score lines  34   a , extending radially outwardly, which are operable to break during the opening operation of the can. The breaking of the score lines is effected by the skirt being driven downwardly as the cap is twisted or rotated and thereby advances downwardly into the socket  18 . Opening of the beverage container will thus be evident by the broken score lines of the skirt  34 , and preferably, by the sections of the skirt  34  that are formed by the broken score lines extending at an angle upwardly, thus extending radially outwardly and radially upwardly. 
         [0037]    The cap  20  is preferably made of a molded plastic material, is sized to fit substantially within the socket  18 , and includes a cam shaped bottom surface  38  formed at the lower or inner end of a substantially cylindrical sidewall  40 . The cam shaped surface  38  may include an integrally formed sharp or pointed projection  39  disposed offset to the center axis of the cap  20  and extending downwardly into the socket  18  when the cap  20  is assembled in the socket  18 . When assembled, the sharp projection  39  is disposed immediately above the score line  26 , so that when the cap  20  moves downwardly during opening of the container  10 , the projection  39  punctures the can at the beginning of the score line  26 , next to the tab hinge  28 , then progressively propagates the rupture along the score line  26  to its terminus on the opposite end of the tab hinge  28 . 
         [0038]    The cam shaped bottom surface  38  may also include a sharp or pointed projection  42  disposed on the center axis of the cap  20  and extending downwardly into the socket  18  when the cap  20  is assembled in the socket  18 . When assembled, the projection is disposed immediate above an X-shaped score line  44 , so that when the cap  20  moves downwardly during opening of the container, the projection punctures the can at the X-shaped score line  44 , thereby relieving internal pressure and assisting in the rupturing of the score line  26  by the sharp projection  39 . 
         [0039]    The opening operation of the beverage container  10  is made possible by forming a cam structure between the socket  18  and the cap  20 . In particular, cam surfaces  46  are formed in the cylindrical sidewall  40  of the cap  20 . The projections  32  are fitted into and engage the cam surfaces  46  such that when the cap  20  is hand-twisted by the consumer, rotational motion of the cap  20  is converted into linear motion of the cap  20  thus driving the cap in a downward direction relative to the socket  18 . As the cap  20  moves downwardly, the score line  26  is ruptured by the sharp projection  39 , then progressively propagates the rupture along the score line  26  to its terminus. In an alternate embodiment, an optional X-shaped score line  44  may be ruptured by the projection  42  immediately before the score line  26  is ruptured by the sharp projection  39 , to thereby relieve internal pressure and assist in the rupture of the score line  26  by the sharp projection  39 . 
         [0040]    As seen in  FIG. 8 , the cap  20  includes a grip element  48  for the consumer to grab when ready to open the beverage container, and also, as described below, for resealing the beverage container after opening. Depending on the contour of the cam surfaces and their direction of orientation, the cap can be rotated in one direction, preferably clockwise for opening, and then in the opposite direction, counterclockwise, to remove the cap during consumption of beverage, and then again back to the can-opening direction for resealing the beverage container if the contents are not entirely consumed.  FIG. 9  shows the symmetry of disposition of the three projections  32 , at approximately equal angular intervals of 120 degrees. Each projection engages a corresponding cam element, such that in the illustrated embodiment, the sidewall  40  of the cap  20  would be contoured, as by forming grooves, to form three cam elements  46   a ,  46   b , and  46   c . The cam elements are shaped and sloped in a manner designed to cause the cap  20  to advance into an opening position without more than a quarter to half a turn, and as measured in radians, this would be no more than 1 to 2 radians. The number of projections and cam elements can be varied, although three provides a balance between cost and effectiveness. 
         [0041]    Referring to  FIGS. 10 and 11 , the cap sidewall  40  includes three equally spaced cam elements  46   a ,  46   b  and  46   c .  FIG. 10  shows the cam elements  46   a  and  46   b  and the grip  48  extending across the page. The bottom surface  47  of the cap  20  includes the projection  42 , acting as a piercing element, which punctures the X-shaped score line  44 , and it further includes a further projection  39  which also acts as a piercing element. The projection is designed and shaped to impinge on the bottom wall  24  of the socket  18  inside and juxtaposed the score line  26 . As the cap  20  is rotated, from the unopened position shown in  FIG. 10 , the cam structure turns the rotational movement to translational movement, thus moving the cap inwardly. As the cap  20  moves inwardly, the projection  39  rotates until, preferably, it reaches the position shown in  FIG. 11 , wherein a portion of the bottom wall  24  breaks away and is pushed inwardly to form the tear panel  25  that remains hinged to the bottom wall  24  by virtue of the score line  26  not extending to a complete loop. The projection  39  starts at the beginning of score line  26  and only travels 90 deg. Thus, it will only have traveled a portion of the length. What pushes the tear panel  25  out of the way is the body of the cam shaped bottom surface  38  going past the plane of the socket  18  bottom wall  24 . Notice that the cam shaped bottom surface  38  protrudes out from the flat annular surface  21 . 
         [0042]      FIGS. 13A through 13D  show a cross sectional view of the cap moving between opening and resealing positions. In  FIG. 13A , the cap  20  is shown in cross section prior to opening the beverage container. Thus, the bottom wall  24  of the socket  18 , the cylindrical sidewall  22  of the socket  18 , and the upper horizontal wall  23  form the lid  16 . As seen in  FIG. 13A , the cap  20  is shown in the storage position, i.e., pre-opening of the can, wherein the socket bottom  24  is not punctured and the contents of the beverage can  10  are air tight for potentially long term storage. The grip element  48  is shown in a first, unopened position. In this position the flat annular surface  21  of the cap  20  is spaced above the socket bottom wall  24 , but the projection  39  is close to or in slight contact with the score line  26 . Similarly, if a second projection  42  is employed at the center of the lower end of the cap  20 , it is also disposed in close proximity to the score line  44  if not slightly touching. 
         [0043]    In  FIG. 13B , the cap  20  is rotated clockwise approximately 90 degrees. Because of the cam surfaces, the cap translates downwardly by a distance sufficient to cause the projection  39  to rupture the score line  26  as the projection moves along the inner side of the score line. The rupture creates a tear panel  25  which is pushed by the projection into the can by rotating downwardly from the hinge  28  formed between the opposite ends of the score line  26 . The opposite ends of the score line are positioned to form a pivot axis for the tear panel  25 . 
         [0044]    After the tear panel  25  is formed, and the cap is disposed at its innermost position relative to the socket, the consumer would then rotate the cap counterclockwise, preferably by turning the grip element  48 . As seen in  FIG. 13C , the cap  20  is shown separated from the beverage container  10 , and can be pocketed by the consumer, or placed in a location for easy access in case the consumer chooses not to consume the entire contents of the beverage container  10 . As evidence that the beverage container has been opened, the skirt  34  may be angled upwardly as a result of the frangible score lines being broken, so that individual sections of the skirt are now biased in an upward direction. Also, when rotating counterclockwise, the cam surfaces  46  and the projections  32  will eventually separate, allowing the cap  20  to be free of the beverage container  10 . 
         [0045]    In the event that the consumer wishes to reseal the beverage container  10 , and as seen in  FIG. 13D , the cap  20  is brought into contact with the socket  18  by the consumer, by bringing the cam surfaces  46  into engagement with the projections  32 . Once this occurs, clockwise rotation will cause the cap  20  to translate downwardly until a sealing, seating arrangement is made between the annular surface  27  of the socket bottom wall  24  and the annular surface  21  of the cap  20 , thereby keeping the contents of the beverage container fresh and safe from foreign contaminants. 
         [0046]    The cap  20  can be removed again and again to gain access to the contents of the beverage container until all contents are consumed. There is no limit to the type of beverages that can be housed in the container  10 , but most commonly “canned” beverages include sodas, beer, juices, etc. It is also within the scope of the present invention that the contents of the containers could be foodstuff, and non-consumable liquids, gels, powders, etc. 
         [0047]    The cam means disclosed herein can be used for caps that provide other functionality for the beverage can  10 . For example, a variation of the cap  20  would be one that could include a passageway extending through the cap  20  with drinking implements formed at the upper, outer end, such as a child&#39;s sip cup, which would allow a child to drink from the beverage container  10  without spilling. Alternatively, the cap  20  could be formed with an infant nipple for feeding formula, juice, water or other beverages suitable for infants. When using drinking implements such as sip cup and baby bottle nipples, a cap  20  would nonetheless have to be employed for opening the container, and then a second “cap” could be used for consuming the contents. In any event, the opening caps and drinking implements could be sold separately from the beverage container, as long as the container included the projections formed in the cylindrical sidewall of the socket. 
         [0048]    Although a wide range of plastic materials could be used to form the cap  20 , other materials could be used, including ceramics and metals. However, for harder materials such as these, it may be necessary to position a gasket between the opposing annular surfaces of the socket and the cap to ensure the best possible seal. 
         [0049]    While the embodiments described herein place the socket and cap in the top of the beverage can, it is possible to have the same opening and resealing structures in the bottom surface  14  of the beverage container  10 . Also, while a cylindrical can has been described herein, other shapes of containers, e.g., oval, rectangular, etc., could also be used. 
         [0050]    The preferred shape of the frangible score line  26  in the bottom of the socket  18  is circular, with a closed end and an open end. The inside score (shallower line) terminates in a curve arcing towards the socket&#39;s cylindrical sidewall to prevent loss of tear panel into the container. The outside score line (deeper line) terminates in circular form spaced from the inside score line. There is a hinged portion of the tear panel that keeps the panel in contact with the lid once ruptured, as described above. 
         [0051]    The projection  39 , described as a piercing element, is intended to be a single point of contact that moves deeper, and radially along the inside of the score line  26  while the cap  20  is rotated. The projection  39  may also include additional areas to further drive the tear panel  25  deeper into the container. A single point will apply more force to breaking the tear panel but additional areas acting in a secondary fashion could help in the opening process. 
         [0052]    The projections  32  used in the socket allow the use of a very shallow socket (as compared to threaded designs) and still provide positive opening, closing and sealing of the cap  20 . The design of the projections  32  also provides for positive stops for open, closed and removable cap positions. As seen in  FIGS. 10 and 11 , each cam element  46   a ,  46   b  and  46   c  includes a sloped portion  50 , a lower detent  52  and an upper detent  54 . Once assembled, the three projections  32  are respectively positioned so that the detents prevent the cap  20  from becoming disconnected from the socket  18 , during transport or storage, and from backing off a sealing position, when the cap  20  is positioned in a resealing position. This can be illustrated with reference to  FIG. 11 , where the projection  32  is shown as a broken line circle. When the cap  20  is in the unopened position, each projection  32  will be positioned next to the lower detent  52 , as seen with the broken line circle  32 . The detent  52  prevents the cap  20  from turning to a position where the projection  32  is disengaged from the cam element  46   c , as for example, if vibration or the like caused the projection to pass out of the sloped portion  50 . Similarly, when the cap  20  is intentionally rotated clockwise, to either open or reseal the beverage container, the projection passes over the upper detent  54  to become locked by interference fit between the detent and the projection. The upper detent thus prevents the cap  20  from inadvertently backing out of the sealing position. Thus, the cap  20  is held in two positions by the detents. The first position can be called a transport securement position and the second can be called a closed position. The distance between the two detents, measured along the rotational axis of the cap  20  is equal to the distance between the resealing surface on the cap  20  and the socket&#39;s bottom surface. The transport securement detent, or lower detent  52  restricts the rotary movement of the cap  20  due to the interference between the stabilizing skirt  34  and the flat upper rim of the socket  20 , as well as the interference between the piercing element or projection  39  and the socket tear panel  25 . 
         [0053]    When turning the cap  20  in the opening direction, e.g., clockwise, the projections  32  on the socket&#39;s cylindrical sidewall follow the sloped portions  50  of the cam elements  46 , which form gradual ramps, and this causes the rotary motion of the cap  20  to be converted to linear or translational movement which drives the cap  20  into the container. This engages the piercing element  39  against the tear panel  25  and provides the force necessary to rupture the frangible score line  26 . Further turning of the cap  20  in the opening direction progressively pushes the tear panel  25  out of the way and into the container, until the projections  32  reach the closed position of the upper detents  54 . A slightly higher point on the sloped portion  50  of the cam elements  46  just before the closed position provides the resistance necessary to keep the cap from backing out. 
         [0054]    When turning the cap  20  opposite the opening direction, the projections  32  follow the same route to their starting positions but after opening, the projections  32  can pass over the transport securement or lower detents  52  because the stabilizing skirt  34  and the tear panel  25  are now not providing any interference between the transport securement or lower detents  52  and the void between the cam elements  46 , allowing the cap  20  to be freed from the container. 
         [0055]    In the embodiments described and illustrated herein, the cam elements  46  are seen as grooves having a sloped portion that terminated at opposite upper and lower ends in a detent, whereby the entire cam elements were formed in the cylindrical sidewall  40  of the cap  20 . It is equally possible to form the cam elements as projections from the surface, integrally formed therewith, or as separate parts connected to the cap. Further, while the projections  32 , acting as cam followers, project from the cylindrical sidewall of the sockets, the socket could have been formed with cam surfaces and the cam followers could have been formed on the cap  20 . The exact size and shapes of the cam surfaces can be selected to correspond to the particular needs of the beverage container. The overall goal is to select a structure that results in an operable torque which can be applied by consumers without exerting excessive effort. 
         [0056]    The structures described above can be made using unique manufacturing processes, which combine some of the known processing steps with new, modified or avoided steps. In one particularly preferred method of making beverage containers, as illustrated in the flow chart of  FIG. 14 , preformed lids are provided from a shell press. Next, sockets are formed in the lids in a conversion press. Next, a score line is formed in the bottom of the socket in the conversion press, either at the same time, or sequentially after the socket is formed. Caps are formed by injection molding, or other suitable means, and the caps are supplied to the assembly line, where they are inserted into the sockets. The caps are then secured to the sockets by press forming the projections by spacing three dies around the socket, all centered on a common plane. The dies are pressed inwardly against the cylindrical sidewall of the socket, and the cap acts as a mandrel against the inner pressing force of the dies, thus forming the projections  32  to project into the grooves of the cam elements. The can lids or ends are then packaged and sent to bottlers, who can then use conventional processing steps to secure the lid to any of a variety of cans or other beverage containers. 
         [0057]    The process described above achieves several cost and environmental advantages over the prior manufacturing techniques. First of all, the lid does not have to be processed to form a rivet, which has conventionally been used to secure the pull tab to the can lid. There is no need for a rivet because there is no need for a pull tab. The rivet required the lid to be made of stronger, thicker material, usually consisting of a different alloy of aluminum as opposed to the material that made up the sidewall and bottom. Moreover, the conventional process would have required the formation of a pull tab, likely to be made of third, different aluminum alloy. Use of three different aluminum materials presented a problem for recycling, whereas in the present invention, a single material can be used to form the can body and the can lid. 
         [0058]    Referring to  FIG. 15 , a further variation of manufacturing process is disclosed. In the first step a pre-formed lid is provided from a shell press with a socket already formed. In the next step, the lid and socket are aligned directionally for a conversion press. Next a score line is created in the conversion press, at the bottom of the socket. Molded caps are provided to the assembly line, and inserted into the molded cap. The molded caps are secured to the socket by forming the projections  32  in a manner described above, in which the cap functions as a mandrel during formation of the projections. Next, the lids with secured caps are packaged and shipped to bottlers or others for conventional filling, sealing, and shipment to customers. As in the previously described manufacturing process, there is no need to form a rivet in the lid, and no need to attach a pull tab to the rivet. Avoiding these steps saves money and makes the resulting product easier to recycle. 
         [0059]    Although specific embodiments of the present invention have been described, it will be understood by those of skill in the art that there are other embodiments that are equivalent to the described embodiments. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrated embodiments, but only by the scope of the appended claims.