Patent Publication Number: US-9884701-B2

Title: Ecology can end with pressure equalization port

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     N/A 
     FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     N/A 
     TECHNICAL FIELD 
     The invention relates to ecology-type stay-on tab beverage can ends; more particularly, the present invention is directed to such a beverage can end with a pressure equalization port which is openable without manually rotating the stay-on tab during an opening sequence. 
     BACKGROUND OF THE INVENTION 
     Typical end closures for beer and beverage containers have an opening panel and an attached leverage tab for pushing the opening panel into the container to open the end. The container is typically a drawn and ironed metal can, usually constructed from a thin plate of aluminum. End closures for such containers are also typically constructed from a cutedge of thin plate of aluminum or steel, formed into a blank end, and manufactured into a finished end by a process often referred to as end conversion. These ends are formed in the process of first forming a cutedge of thin metal, forming a blank end from the cutedge, and converting the blank into an end closure which may be seamed onto a container. 
     These types of container ends have been used for many years, with almost all such ends in use today being the “ecology” or “stay-on-tab” (“SOT”) ends in which the tab remains attached to the end after a tear panel, including large-opening ends (“LOE”), is opened. The tear panel being a portion of the can end defined by a frangible score length. The tear panel may be opened, that is the score may be severed, and the tear panel displaced at an angular orientation relative to the remaining portion of the can end, thus creating a pour opening through which the beverage may be poured from the container. The tear panel remains hingeably connected to the remaining portion of the can end by a hinge segment, leaving an opening through which the user draws the contents of the container. In an LOE, the pour opening is about 0.5 square inches in area. 
     Opening of the tear panel is operated by the tab which is attached to the can end by a rivet through a rivet island on the tab. The tab is typically attached to the can end such that a nose of the tab extends over a proximal portion of the tear panel in a stowage position. A lift end of the tab is located opposite the tab nose and provides access for a user to lift the lift end, such as with the user&#39;s finger, to force the nose against the proximal portion of the tear panel. With most can ends, the stowage position and opening position are in the same location; however, some can ends known in the art require rotation of the tab from a stowage position to the opening position prior to an opening sequence, i.e. the fracturing of the frangible score. 
     When the tab nose is forced against the tear panel, the score initially ruptures at a vent region of the score. This initial rupture of the score is primarily caused by the lifting force on the tab resulting in lifting of a central region of the can end, including the rivet and immediately adjacent the rivet. As the tab is lifted further, the score rupture propagates along the length of the score, eventually stopping at the hinge segment. 
     Venting is an initial release of pressure from within a pressurized container upon initial fracture of the score about the tear panel, typically upon the initial lifting of the lift end of the tab by a user. 
     One problem associated with these opening systems is pourability of the beverage from the container. Because these ends are not typically outfitted with a pressure equalization aperture, the beverage may “glug” as air enters the beverage container through the pour opening to replace the volume of the quickly exiting beverage emptied from the container. “Glug” refers to an uneven flow caused by the outside air attempting to enter the container through the pour opening. Thus, pressure equalization differs from venting in that venting is the initial release of pressure in a pressurized container, i.e. the “pop”, and pressure equalization is the act of replacing the volume of beverage with a volume of air. 
     Many years ago, prior to beverage containers having frangible tear panels of any sort, users opened beverage containers with church keys having a downturned sharpened beak used to pierce the end closure. The user would pierce the end closure twice creating a pour opening and an equalization opening. This method is often used today by beverage vendors at sporting stadiums and the like where speed of beverage delivery is important to serve many customers in short periods of time. Many efforts have been made to outfit SOT ends with some sort of equalization opening. None of these attempts have been universally adopted due in no small part to the significant drawbacks associated with each one. 
     For example, one method of improving pourability of SOT end closures involves enlarging the pour opening. However, the openings can rarely be made large enough to fully eliminate glugging. Additionally, when the openings are made very large, unwanted spillage becomes an issue from splashing, spewing, or spitting of the beverage through the very large pour opening. Moreover, the larger pour opening typically requires manual rotation of the tab about the rivet to apply tab nose forces in a plurality of locations on the closure to bend an enlarged tear panel into the container. Fully flexing a hinge region on the tab several times results in work hardening of the rivet island causing the metal to become brittle which could result in the tab undesirably breaking free from the closure. Also, the user must manually rotate the tab to a precise location without instruction in order for the tear panel to produce the larger pour opening. 
     Some designers have proposed providing a second tear panel in the end closure. These designs generally rely on use of an external puncturing tool, e.g. the church key, or using the SOT to open the second tear panel. Obviously requiring the user to supply an external puncturing tool is undesirable as it represents devolving of the art to the days of the church key. Using the SOT to open the second tear panel requires the manual rotating and flexing of the SOT described above which shares the drawbacks of the larger opening ends also described above. Finally, the size and location of these second tear panels are undesirable because the openings are too large resulting in spillage and/or too close to pour opening to create a sufficient pourability advantage. 
     One proposed method of eliminating manual rotation of the tab to open an equalization port requires providing a rocking tab or “teeter tauter” tab wherein one end of the tab is used to open the pour panel while the opposite end or some other portion of the tab is used to open the equalization port. However, rocking of the tab is undesirable because it could result in premature opening of one or both of the tear panels. 
     Efforts have placed such a vent feature close to or under the rivet island of the SOT and/or within a coined region surrounding the rivet. These features consist of a second frangible score that is fractured when the SOT is lifted to fracture the frangible score which partially defines the pour opening. These locations and methods are undesirable because they are located too close to the pour opening which could lead to unwanted spillage through the vent, and the method of severing does not provide the user with the option of using or not using the vent because the second score is automatically or naturally severed when the user fractures the main score partially defining the pour opening. 
     Another recent attempt at providing improved pour includes formation of a deboss channel at approximately a 1 o&#39;clock position of the pour opening. There is some debate whether the deboss channel provides any improvement in pourability. 
     Thus, the problems associated with prior attempts to provide a pressure equalization port primarily center on the size and/or location of the port and/or method of opening. A non-exhaustive list of problems associated with these prior attempts includes the following singularly and in any combination: not providing the user an option of using/opening the port due to location, undesirably and/or unnecessarily too large, located too close to the dispensing opening, requires use of an enteral tool such as a church key, requires use of a user&#39;s finger to push down on the center panel in direct engagement therewith which could cause cuts on the user&#39;s finger due to sharp edges on the center panel, possible premature opening of the port, unacceptable/nonexistent pressure equalization within the container, and spills and splashes of the contents of the container. As is explained in greater detail below, the present invention reduces or eliminates these problems with container ends. The present invention provides variations for overcoming the specific difficulties associated with design, manufacture and use of large-open beverage container ends. 
     The present invention is provided to solve the problems discussed above and other problems, and to provide advantages and aspects not provided by prior end closures of this type. A full discussion of the features and advantages of the present invention is deferred to the following detailed description, which proceeds with reference to the accompanying drawings. 
     SUMMARY OF THE INVENTION 
     A first aspect of the present invention is directed to an ecology stay-on tab beverage can end. The ecology stay-on tab beverage can end has a circumferential curl centered about a longitudinal axis. A circumferential wall extends downwardly from the curl. A circumferential strengthening member is located downwardly from the wall. A center panel is located radially inwardly from the strengthening member and is centered about the longitudinal axis. The center panel has a rivet which attaches a tab to the center panel. A first curvilinear segment of frangible score is severable to form a vent opening and a pressure equalization port. A second curvilinear segment of frangible score has opposing terminal ends separated by a non-frangible hinge segment of the center panel. The second curvilinear segment of frangible score is severable to form a pour opening. A lifting of a lift end the tab actuates an opening sequence in which the first curvilinear segment of frangible score is severed causing the vent opening and the pressure equalization port to form before the pour opening is completely formed. 
     The first aspect of the invention may include one or more of the following features, alone or in any reasonable combination. The ecology stay-on tab beverage can end may further comprise a tear panel defined by the second curvilinear segment of frangible score and the non-frangible hinge segment which retains the tear panel to an adjacent portion of the center panel when the pour opening is formed, and a first diametric axis of the ecology stay-on tab beverage can end which extends lengthwise through the tab from the lift end of the tab to a nose end of the tab opposite the lift end wherein a portion of the nose end of the tab lying within an arc area of a circular arc subtending a 90 degree angle, having a center point at the center point of the rivet and bisected by the first diametric axis, has a segment located outwardly of the tear panel when the lifting of the lift end of the tab actuates the opening sequence; this segment of the nose end of the tab may first contact a portion of the center panel located beyond a boundary of the tear panel during initial lifting of the lift end of the tab which actuates the opening sequence. The nose end of the tab may have a cleat which extends over the tear panel when the lifting of the lift end of the tab actuates the opening sequence. The ecology stay-on tab beverage can end may further comprise a first diametric axis of the ecology stay-on beverage tab extending lengthwise through the tab from the lift end of the tab to a nose end of the tab opposite the lift end when the tab is in position to begin the opening sequence, a second diametric axis perpendicular to the first diametric axis wherein four quadrants of substantially equal area of the ecology stay-on tab beverage can end are formed, and a score line having opposing terminal ends and comprising the first curvilinear segment of frangible score and the second curvilinear segment of frangible score therebetween, wherein the score line has portions located in each of the four quadrants. The tab may comprise a central webbing and a void region partially surrounding a rivet island, wherein the void region has opposing legs extending along opposite sides of the rivet island, wherein the rivet island has a rivet hole through which the rivet passes, and wherein the rivet hole is offset on the rivet island such that it is located closer to a first opposing leg than a second opposing leg. The ecology stay-on tab beverage can end may further comprise a tear panel defined by the second curvilinear segment of frangible score and the non-frangible hinge segment which retains the tear panel to an adjacent portion of the center panel when the pour opening is formed and a raised ramp which is located on the center panel outwardly of the tear panel, wherein a portion of the nose end of the tab engages the raised ramp during the opening sequence, wherein a force provided by the tab nose to the center panel migrates towards the tear panel as a result of the tab engaging the raised ramp. The opening sequence may comprise, in order, formation of the vent opening and formation of the pressure equalization port upon severing the first curvilinear segment of frangible score until the severing of the first curvilinear segment of frangible score ceases. The ecology stay-on tab beverage can end may further comprise a score line having opposing terminal ends and comprising the first curvilinear segment of frangible score adjacent a first terminal end of the score line and extending therefrom and a non-frangible segment of the score line joining the first curvilinear segment of frangible score with the second curvilinear segment of frangible score, wherein the second curvilinear segment of frangible score extends from the non-frangible segment of the score line to a second terminal end of the score line. The pour opening may have an area no less than 0.25 square inches. The pour opening may be created as the lifting of the tab continues without manual rotation of the tab by a user. The ecology stay-on tab beverage can end may further comprise a score line having opposing terminal ends and comprising the first curvilinear segment of frangible score adjacent a first terminal end of the score line and extending therefrom and a third curvilinear segment of frangible score of the score line joining the first curvilinear segment of frangible score with the second curvilinear segment of frangible score, wherein the second curvilinear segment of frangible score extends from the third curvilinear segment of frangible score line to a second terminal end of the score line. The lifting of the tab may occur from a stowage position of the tab without manual rotation of tab prior to lifting of the tab from the stowage position. The opening sequence may be completed without manually rotating the rivet island of the tab about the rivet. The nose end  30  may be defined by a portion of a perimeter of the tab including a curl which is located within an arc area of a circular arc subtending a 90 degree angle and wherein the circular arc has a center point at the center point of the rivet and is bisected by the first diametric axis. Lifting of the tab may cause the rivet island of the tab to rotate about rivet without conscious tab rotation provided by a user. The first and second curvilinear segments of frangible score may form portions of a score line, wherein the score line further comprises a fork, and during the opening sequence, fracture of the score line is bi-directional, simultaneously continuing in a first path along the first curvilinear segment of frangible score and in a second path along a bypass segment of frangible score to the second curvilinear segment of frangible score. During the opening sequence, according to a clock-like reference, a fracture of the first curvilinear segment of frangible score may proceed in a first direction to form the pressure equalization port as a fracture of the second curvilinear segment of frangible score proceeds in an opposite direction to form a pour opening. 
     A second aspect of the invention is also directed to an ecology stay-on tab beverage can end. The ecology stay-on tab beverage can end comprises a circumferential curl centered about a longitudinal axis. A circumferential wall extends downwardly from the curl. A circumferential strengthening member is located downwardly from the wall. A center panel is located radially inwardly from the strengthening member and is centered about the longitudinal axis. A rivet attaches a tab to the center panel. A first curvilinear segment of frangible score is severable to form a vent region and a pressure equalization port. A second curvilinear segment of frangible score has opposing terminal ends separated by a non-frangible hinge segment of the center panel. The second curvilinear segment of frangible score is severable to form a pour opening. A lifting of a lift end the tab actuates an opening sequence in which a force provided by the nose end of the tab to the center panel migrates from a location outside a boundary of the tear panel to a location within the boundary of the tear panel. 
     A third aspect of the invention is also directed to an ecology stay-on tab beverage can end. The ecology stay-on tab beverage can end comprises a circumferential curl centered about a longitudinal axis. A circumferential wall extends downwardly from the curl. A circumferential strengthening member is located downwardly from the wall. A center panel is located radially inwardly from the strengthening member and is centered about the longitudinal axis. A tear panel is defined by a frangible score having terminal ends separated by a non-frangible hinge segment which retains the tear panel to the center panel upon opening the ecology stay-on tab beverage can end. A rivet attaches a tab to the center panel. The tab comprises central webbing, a rivet island having a rivet hole through which the rivet passes, a void region partially surrounding a rivet island having opposing legs extending along opposite sides of the rivet island, and a tab hinge extending from between the opposing legs. The rivet hole is offset on the rivet island such that it is located closer to a first opposing leg than a second opposing leg. 
     A fourth aspect of the invention is also directed to an ecology stay-on tab beverage can end. The ecology stay-on tab beverage can end comprises a circumferential curl centered about a longitudinal axis. A circumferential wall extends downwardly from the curl. A circumferential strengthening member is located downwardly from the wall. A center panel is located radially inwardly from the strengthening member and is centered about the longitudinal axis. A tab is attached to the center panel. A tear panel is defined by a frangible score having terminal ends separated by a non-frangible hinge segment which retains the tear panel to the center panel upon opening the ecology stay-on tab beverage can end. A single lifting motion of a lift end of the tab without manually rotating the rivet island about the rivet creates, in order, a vent opening, a pressure equalization port and a pour opening. The ecology stay-on tab beverage can end may further comprise a raised ramp forming a tapered surface on a public side of the center panel wherein engagement by a nose end of the tab with the raised ramp causes rotation of the rivet island about the rivet during the single lifting motion of the lift end of the tab. 
     Other features and advantages of the invention will be apparent from the following specification taken in conjunction with the following drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To understand the present invention, it will now be described by way of example, with reference to the accompanying drawings in which: 
         FIG. 1  is a top view of an embodiment of the present invention with a substantially translucent tab to reveal structure of a can end beneath the tab; 
         FIG. 2  is a cross-sectional view of a can end; 
         FIG. 3  is a top view of an embodiment of the present invention with a substantially translucent tab to reveal structure of a can end beneath the tab; 
         FIG. 4  is a top view of an embodiment of the present invention with a substantially translucent tab to reveal structure of a can end beneath the tab; 
         FIG. 5  is a top view of an embodiment of the present invention with a substantially translucent tab to reveal structure of a can end beneath the tab; 
         FIG. 6  is a top view of an embodiment of the present invention with a substantially translucent tab to reveal structure of a can end beneath the tab; 
         FIG. 7  is a top view of an embodiment of the present invention with a substantially translucent tab to reveal structure of a can end beneath the tab and illustrating a vent opening and pressure equalization port formed subsequent to initial lifting of a lift end of the tab during an opening sequence; 
         FIG. 8  is a top view of an embodiment of the present invention with a substantially opaque tab illustrating initial opening of a tear panel to form a pour opening and automatic rotation of the tab upon continued lifting of a lift end of the tab by a user; 
         FIG. 9  is a top view of an embodiment of the present invention with a substantially opaque tab illustrating continued opening of a tear panel to form a pour opening and further automatic rotation of a tab upon continued lifting of a lift end of the tab by a user; 
         FIG. 10  is a top view of an embodiment of the present invention; 
         FIG. 10A  is a cross-sectional view of a segment of a center panel illustrating a raised ramp which contributes to automatic rotation of a rivet island of a tab about a rivet attaching the tab to a can end according to an embodiment of the present invention; 
         FIG. 11  is a top view of an embodiment of the present invention showing a portion of a nose end of a tab located within an arc area of a circular arc subtending a 90 degree angle wherein the circular arc has a center point at the center point of a rivet and is bisected by a first axis and wherein a portion of a cleat formed on the tab is also located within the arc area; 
         FIG. 12  is a top view of an embodiment of the present invention showing a preferred location of a portion of a nose end of a tab located within an arc area of a circular arc subtending a 45 degree angle wherein the circular arc has a center point at the center point of a rivet and wherein a first radius extends along a first axis between a second quadrant and a third quadrant and a second radius is located in the second quadrant; 
         FIG. 13  is a top view of an alternative embodiment of the present invention showing a portion of a nose end of a tab located within an arc area of a circular arc subtending a 90 degree angle wherein the circular arc has a center point at the center point of a rivet and is bisected by a first axis and wherein a portion of a cleat formed ion the tab is also located within the arc area and wherein a bridge of the score creates a fork in a frangible score path wherein a breaking of the score proceeds in two separate directions at the fork to open a pressure equalization port along one direction of the fork and to open the tear panel to create a pour opening along a second direction of the fork; and 
         FIG. 14  is a top view of an alternative embodiment of the present invention showing a portion of a nose end of a tab located within an arc area of a circular arc subtending a 90 degree angle wherein the circular arc has a center point at the center point of a rivet and is bisected by a first axis and wherein a portion of a cleat formed on the tab is also located within the arc area and wherein the score line is designed to open bi-directionally such that the frangible score defining the tear panel fractures along a counterclockwise path while the frangible score that fractures to create a pressure equalization port opens in a clockwise path. 
     
    
    
     DETAILED DESCRIPTION 
     While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated. 
     The present invention provides a can end aimed at providing a suitable pressure equalization port which allows a volume of fluid to enter a headspace above a beverage within a beverage container. This allows the beverage to pour more smoothly and rapidly through a pour opening in the can end. The pressure equalization port allows the fluid to enter the headspace to replace the volume of the quickly exiting liquid beverage emptied from the container through pour opening. The present invention is directed to a means for providing an automatically opening pressure equalization port that opens naturally during the course of an ecology SOT can end opening sequence. The pressure equalization port of the present invention is intended to overcome the drawbacks of prior such pressure equalization ports. More specifically, it is automatically openable rather than selectively openable. It is operable/openable by a tab already attached to the can end, and it is openable as a step in the ordinary opening sequence of the can end. Unlike some prior art tabs, it does not require manual rotation of the tab as will be described below or very little of such manual rotation. Instead, the tab will naturally rotate upon ordinary lifting of a lift end of the tab to open both the equalization port and a pour opening during the ordinary opening of the pour opening. Finally, it cannot be debated whether the pressure equalization port provides an improvement in pourability of the beverage from the beverage container. 
     Referring generally to the figures, a beverage can end  10  for a container has a center panel  12  separated from a seaming curl  14  by a circumferential wall  15  extending downwardly from the seaming curl  14  to a strengthening member  16  which is joined to the center panel  12 . The container is typically a drawn and ironed metal can, usually constructed from a thin plate of aluminum or steel. Beverage can ends for such containers are also typically constructed from a cutedge of thin plate of aluminum or steel, formed into blank end, and manufactured into a finished end by a process often referred to as end conversion. 
     The can end  10  can be joined to a container body by the seaming curl  14  which is joined to a mating curl of the container body. The seaming curl  14  of the can end  10  is integral with the center panel  12  by the circumferential wall  15  and the strengthening member  16 , typically either a generally U-shaped countersink or a fold, which is joined to a peripheral edge of the center panel  12 , defining an outer perimeter of the center panel  12 , often through an additional strengthening feature such as a circumferential step or other circumferential wall. This type of means for joining the center panel  12  to a container body is presently the typical means for joining used in the industry, and the curl structure described above is formed in the process of forming the blank end from a cutedge of metal plate, prior to the end conversion process. However, other means for joining the center panel to a container may be employed with the present invention. 
     The steps of manufacturing the can end  10  begin with blanking the cutedge, typically a round or non-round cutedge of thin metal plate. Examples of non-round cutedge blanks include elliptical cutedges, convoluted cutedges, and harmonic cutedges. A convoluted cutedge may be described as generally having three distinct diameters, each diameter being 45° relative to the others. The cutedge is then formed into a blank end by forming the seaming curl, countersink, panel radius and the center panel. 
     The conversion process for this type of beverage can end includes the following steps: forming a rivet by first forming a projecting bubble in the center of the panel and subsequently working the metal of the bubble into a button and into the more narrow projection of metal being the rivet; forming the tear panel by scoring the metal of the panel wall; forming an inner bead or panel on the tear panel; forming a deboss panel by bending the metal of the panel wall such that a central area of the panel wall is slightly lower than the remaining panel wall; staking the tab to the rivet; and other subsequent operations such as wipe-down steps to remove sharp edges of the tab, lettering on the panel wall by scoring, incising, or embossing (or debossing), and restriking the rivet island. 
     The seaming curl  14  defines an outer perimeter of the beverage can end  10 . It is generally centered about a longitudinal or vertical axis  50 , typically located at a center of the rivet. 
     The center panel  12  has a displaceable tear panel  20  defined by a frangible score and a non-frangible hinge segment  25 . The tear panel  20  of the center panel  12  may be opened, that is the frangible score may be severed and the tear panel  20  displaced at an angular orientation relative to the remaining portion of the center panel  12 , while the tear panel  20  remains hingeably connected to the center panel  12  through the hinge segment, to define a dispensing port or pour opening  20 ′ (see  FIG. 9 ). In this opening operation, the tear panel  20  is displaced at an angular deflection. More specifically, the tear panel  20  is deflected at an angle relative to the plane of the center panel  12 , with the vortex of the angular displacement being the hinge segment. 
     The tear panel  20  is formed during the conversion process by a scoring operation. The tools for scoring the tear panel  20  in the center panel  12  include an upper die on a public side  34  having a scoring knife edge in the shape of the tear panel  20 , and a lower die on the product side to support the metal in the regions being scored. When the upper and lower dies are brought together, the metal of the panel wall  12  is scored between the dies. This results in the scoring knife edge being embedded into the metal of the panel wall  12 , forming a score line  22  which appears as a wedge-shaped recess in the metal. The metal remaining below the wedge-shaped recess is the residual of the score line  22 . Therefore, the score line  22  is formed by the scoring knife edge causing movement of metal, such that the imprint of the scoring knife edge is made in a public side  34  of the panel wall  12 . 
     The center panel  12  has a public side  34  and an opposing product side  35  and further includes a tab  26 . The tab  26  has a generally elongated body along a diametric axis  72  extending through a tab nose  30 , a central webbing  42  and the lift end  32 . Typical prior art can ends often have a tab  26  which is staked in the final steps of the conversion process by staking the area of the center panel  12  adjacent and under the rivet island  46  at an angle, to bias the tab  26  such that the lift end  32  of the tab  26  rests close to the center panel  12 . The center panel  12  may also have a recess near the lift end  32  of the tab  26  to allow for easier finger access. 
     The opening of the tear panel  20  is operated by the tab  26  which is attached to the center panel  12  by a rivet  28  spaced from the tear panel  20 , generally through a rivet aperture in the rivet island  46 . The lift end  32  of the tab  26  is located opposite the tab nose  30  and provides access for a user to lift the lift end  32 , such as with the user&#39;s finger. 
     Alternatively, the tab  26  may be attached to the center panel  12  by an adhesive. 
     For purposes of this description, the nose end  30  refers to that portion of the perimeter of the tab  26  including the curl  38  (see  FIG. 2 ) which is located within an arc area of a circular arc subtending a 90 degree angle. The circular arc has a center point at the center point of the rivet  28  and is bisected by the first axis  72  (see  FIG. 11 ). 
     The rivet  28  is surrounded by a circular coined region of the center panel  12 . The coined region is a compressed portion of the center panel  12  through which the score line  22  generally travels. A raised, curvilinear bead may be located about the coined region so that it partially surrounds the coined region. 
     The central webbing  42  of the tab  26  is located between the nose end  30  and the lift end  32 . The central webbing  42  includes a hinge region and a rivet island  46  surrounding the rivet  28 . An opening or void region  48  of the tab webbing  42  provides an exposed area of the center panel  12 . The void region  48  has a curvilinear geometry which borders the rivet island  46  and at least partially surrounds the rivet  28 , with a first leg of the void region  48  being disposed generally to one side of the rivet  28 , and a second leg being generally disposed on an opposite side of the rivet  28 . The hinge region of the tab webbing  42  includes a hinge line which is defined by a substantially straight line passing between a terminal end of the first leg and a terminal end of the second leg of the void region  48 . It may also be necessary to add material to the tab webbing  42 , modify the radius of the curl, add beading, or other strengthening means to ensure that this area is strong enough wherein the tab  26  bends at the hinge region during opening. 
     The void region  48  is within the tab webbing  42 . The void region  48  may have a generally arch-shaped configuration. In this configuration, the rivet island  46  again follows the general shape of the void region  48 . 
     The hinge region of the tab  26  may be adapted to have a hinge line which is not perpendicular to an axis coincident with the diametric line. Rather, the hinge line intersects the first axis at an oblique angle. Thus, one embodiment of the present invention has a void region  48  with a first leg which is closer to an outer edge of the tab nose  30 , and closer to the tear panel  20 , than the second leg. Thus, the hinge line of the tab  26  is oriented at an oblique angle relative to the diametric line, as it is neither parallel nor perpendicular to the diametric line. See, e.g.,  FIGS. 4-6 . The oblique hinge line is described in U.S. Pat. No. 6,024,239 which is hereby incorporated by reference as if fully set forth herein. 
     The alteration of the hinge line orientation relative to the first axis results in a structure which directs the path of the tab  26  during opening of the tear panel  20 , caused by lifting force on the lift end  32  to rotate the tab  26  about the hinge line  44  and cause angular displacement of the tab body. 
     The figures represent only one example of the rivet island  46  configuration. However, those of ordinary skill in the art would understand that the rivet island  46  and the void region  48  can take any number of shapes without departing from the spirit of the invention, including but not limited to all notch or lance type rivet islands. 
     The webbing  42  further comprises a grab portion. The grab portion is adapted for user manipulation. Typically, the grab portion includes a finger hole or the like. The finger hole is separated from the void region  48  by a thin segment of the webbing  42 , under which the raised bead lies. 
     A deboss panel  66  is formed in the public side  34  of the central panel  12 . The deboss panel  66  is formed in the central panel  12  using conventional die-forming techniques. The tab  26  and the tear panel  20  are typically fully recessed within the deboss panel  66 . 
     For purposes of description and location of elements, a first axis  72  of the can end  10  extends through the nose end  30  and lift end  32  of the tab  26  and through a center of the rivet  28 , generally bisecting a tab of bilateral symmetry. Thus, the first axis  72  may have a length equal to a diameter of the can end  10 , assuming a round can end  10 . Therefore, in one embodiment the first axis  72  is a diametric axis. A second axis  82  is perpendicular to the first axis  72 . It may also pass through the center point of the rivet  28 . Therefore, it too may be a diametric axis. The first and second axes  72 , 82  create four quadrants I-IV of the can end  10  having substantially equal surface areas. 
     According to an embodiment of the present invention, the score line  22  travels or extends through all four quadrants of the can end  10 . It has a beginning end  22   a  and a terminal end  22   b.    
     As illustrated, for discussion purposes, and as is the case for all known commercially available beverage containers of this type, a portion of the score line  22  is severed during an opening sequence which progresses in a clockwise fashion from a vent region towards the terminal end  22   b  of the score line  22 . One of ordinary skill in the art could readily adapt the teachings set forth herein to a can using a counterclockwise opening sequence if so desired. 
     Starting with the beginning end  22   a  and moving clockwise about the score line  22 , the score line comprises a first segment  70 . The first segment  70  is a first curvilinear segment of frangible score. This first segment  70  comprises a vent region  70   a  and a pressure equalization port region  70   b . As is typically the case with most, if not all, commercially available ecology beverage can ends, the vent region  70   a  is located at least partially beneath the tab  26  and has a segment lying very close to the rivet  28 . As will be described below, the vent region  70   a  is the location along the score line  22  where opening of the tear panel  20  is initiated. The vent region  70   a  is where an initial “pop” takes place and where an internal pressure within beverage container is safely exhausted during the opening sequence as the score line  22  in the vent region  70   a  is fractured. The concept of a vent region is generally well-known in the prior art, although the inventors believe the vent region  70   a  of their can end includes features not taught by the prior art. 
     Proceeding further clockwise about the score line  22  from the vent region  70   a , the pressure equalization port region  70   b  is located adjacent the vent region  70   a . This pressure equalization port region  70   b  is an automatically openable pressure equalization port. Stated another way, in the first segment  70  of the score line  22 , the pressure equalization port region  70   b  automatically opens during the opening sequence forming a pressure equalization port or opening. This will be explained in more detail below. 
     It should be noted that the first segment  70  begins in the third quadrant of the can end  10  and proceeds from the third quadrant to the second quadrant and from the second quadrant upwardly to the first quadrant and radially outwardly relative to the center of the rivet  28 . 
     A second segment  86  of the score line  22  continues from the first segment clockwise about the score line  22 . The second segment  86  may be of a frangible or non-frangible score. 
     The second segment  86  begins in the first quadrant and continues to extend radially outwardly relative to the center of the rivet  28  and curving towards the second quadrant. 
     The second segment  86  continues curving until it extends into the second quadrant and the curve directs the second segment back radially inwardly relative to the center of the rivet  28 . 
     A third segment  90  of the score line  22  continues from the second segment  86 . The third segment  90  comprises a second curvilinear segment of frangible score. The second curvilinear segment of frangible score is fracturable to a location at, or very near, the terminal end  22   b  of the score line  22  to form the pour opening  20 ′ as the tear panel  20  is forced downwardly into the beverage container during the opening sequence. 
     The third segment  90  preferably extends from the second segment  86  within the second quadrant through a curve adjacent a ramp  94  located radially outwardly of the third segment  90 . The curve directs the third segment  90  radially outwardly relative to the center of the rivet  28  long or adjacent the first axis  72  separating the second quadrant from the third quadrant. The third segment  90  continues on a curvilinear path through the third quadrant and into the fourth quadrant similar to most commercially available LOE beverage container lids. 
     The pour panel  20  is defined by the third segment  90  and a hinge portion created between the terminal end  22   b  of the score line  22  and the onset of fracture of the second curvilinear segment of frangible score in the third segment  90 . 
     It is contemplated that all or some portion of a length of the second segment  86  of the score line  22  will not fracture during the opening sequence. The entire length of the second segment  86  of the score line  22  extends between points A and B as shown in the figures. This structure and opening sequence allows for elimination of the check slot. The check slot is defined by a region of thickened residual in the score line  22  which slows propagation of the fracture of the score line  22  to allow the pressure in the beverage container to vent properly. 
     Alternatively, the second segment  86  of the score line  22  or a portion thereof may be absent altogether such that the first segment  70  of the score line  22  and the third segment of the score line  22  are separated by a non-scored region. This embodiment has a similar opening sequence to the other embodiments in that the vent region  70   a  opens initially followed by the equalization port region  70   b ; then the tear panel  20  opens forming the pour opening  20 ′. 
     Optionally, a curvilinear bead  98  may be formed in the center panel  12  for stiffening. The bead may be recessed or raised, but is preferably a recess. The bead  98  will stiffen or strengthen the area of the center panel  12  between the first and second segments  70 , 86  of the score line  22 . The curvilinear bead  98  may extend to a point adjacent the third segment  90  between the first segment  70  and the third segment  90  such that the curvilinear bead  98  has a first end wherein the curvilinear bead  98  extends from a first point in the second quadrant adjacent the second axis  82  to a second end located at a second point in the second quadrant adjacent the first axis  72  and a distance farther away from the second axis  82  than the first point. 
     An anti-fracture score  102  may be place adjacent the score line  22  as is known in the art. 
     The opening sequence may be described as follows. 
     The tab  26  begins in a stowage position as illustrated (see, e.g.  FIGS. 1, 3, and 4-6 ). The stowage position is the position of the tab  26  in which the beverage container is customarily delivered, i.e. handled subsequent to filling and prior to opening. Here, in the stowage position, the first axis  72  extends from the lift end  32  of the tab  26  through the nose end  30  of the tab  26 . As shown in  FIG. 11 , a portion of the curl  38  of the nose end  30  of the tab  26  is located within an arc area or sector of a circular arc  300  subtending a 90 degree angle. The circular arc has a center point at the center point of the rivet  28  and is bisected by the first axis  72 . The portion of the nose end  30  of the tab has a segment located outwardly of a boundary of the tear panel  20  when in the stowage position and prior to a user actuated lifting of the lift end  32  of the tab  26  which commences the opening sequence. Thus, in the present invention, the pour panel opening position, or score line opening position, is also the stowage position. This segment of the nose end  30  of the tab  26  located outwardly of the tear panel first contacts a portion of the center panel located beyond a boundary of the tear panel during initial lifting of the lift end of the tab which actuates the opening sequence. The user actuated lifting of the tab  26  is directed directly upwardly relative to the public side  34  of the center panel  12  without user introduced rotation of the rivet island  46  of the tab  26  about the rivet  28  in either a clockwise or counterclockwise direction. 
     More preferably, as illustrated in  FIG. 12 , the segment of the nose end  30  of the tab  26  which first contacts the center panel  12  during the opening sequence is located within an arc area of a sector of a circular arc  400  subtending a 45 degree angle. This circular arc  400  also has a center point at the center point of the rivet. However, this circular arc has a first radius extending along the first axis  72  between the second and third quadrants and a second radius located within the second quadrant such that the arc area of this circular arc  400  is located within the second quadrant. 
     In the stowage position and the initial score line breaking position, a portion of the nose end  30  of the tab  26  lying outside of the boundary of the tear panel  20  may engage the ramp  94 . (See, e.g.,  FIGS. 3-5 ). This engagement prelifts the nose end  30  and biases the lift end  32  somewhat downwardly. 
     The tab nose  30  is forced against the ramp  94 , and the score line  22  initially ruptures at a vent region  70   a  of the score line  22 . This initial rupture of the score line  22  is primarily caused by the lifting force on the tab  26  resulting in lifting of a central region of the center panel  12 , including and immediately adjacent the rivet  28 , which causes separation of the residual metal of the score line  22  in the vent region  70   a . The force required to rupture the score line  22  in the vent region  70   a , typically referred to as the “pop” force, is a lower degree of force relative to the force required to propagate other regions of the score line  22  by continued lifting of the lift end  32  of the tab  26 . (See  FIG. 7 ). 
     Thus, similar to prior art can ends, the initial lifting of the tab  26  causes the first segment  70  of the score line  22  to fracture and the pressure within the beverage container to vent out of the beverage container as the vent region  70   a  is fractured forming a vent opening  104 . Continued lifting of the tab  26  causes the fracture of the score line  22  in the first segment  70  to propagate to the pressure equalization port region  70   b  wherein the fracture of the score line  22  creates a pressure equalization port or opening  106  in the score line  22  through which the pressure within the beverage container may be equalized during pouring, resulting in a smoother pour. 
     It should be noted that the lifting of the lift end  32  of the tab  26  by the user causes the score line  22  in the vent region  70   a  to fracture. Continued lifting causes the pressure equalization port  106  to be formed as the score line  22  continues to fracture. At this point, bending deflection of the center panel  12  into a headspace above a beverage in a previously sealed container does not take place. The lifting of the lift end  32  of the tab  26  causes the tab nose  30  to initially press against the center panel  12  outside a periphery or boundary of the tear panel  20  in the area described above which provides further leverage against which the rivet  28  and the area of the center panel  12  near the rivet  28  to be lifted somewhat higher to propagate fracture of the first segment  70  past the vent region  70   a  and into the pressure equalization port region  70   b.    
     Continued lifting of the tab  26  forces the nose end  30  against the ramp  94 . The ramp  94  is tapered or angled (see  FIGS. 10 and 10A ) such that a force provided by the nose end  30  of the tab  26  migrates across the center panel  12  from the ramp  94  towards the tear panel  20 . The taper or angle of the ramp  94  causes the rivet island  46  of the tab  26  to naturally rotate about the rivet  28  without the user consciously ceasing the lifting of the tab, then rotating the rivet island  46  of the tab  26  to position the nose end  30  of the tab  26  to a new location, before resuming the lifting of the tab  26  to fracture the score line  22 . In the embodiment illustrated, the nose end  30  of the tab  26  rotates clockwise towards the tear panel  20 . Thus, the angle or taper of the ramp  94  angles downwardly towards the third quadrant in the embodiment illustrated. This helps the tab deflect to the tear panel  20  during the opening sequence. 
     Thus, a user actuated lifting of the lift end  32  of the tab  26  will actuate the opening sequence in which the first curvilinear segment of frangible score  70  is severed causing the vent opening  104  and the pressure equalization port  106  to form before the same lifting of the tab  26  causes the pour opening  20 ′ to be completely formed. See, e.g., the sequence illustrated in  FIGS. 7-9 . 
     This differs from most prior art can ends. Typically, in the prior art, one of two opening sequences takes place. Either the tab  26  is lifted straight up and continues moving in the same direction to force the tear panel  20  downwardly into the beverage container. Or, the lifting of the tab  26  is paused, and the rivet island  46  of the tab  26  is manually rotated during this dwell period, then the lifting of the tab  26  is continued with the nose  30  relocated on the center panel  12 . With the opening sequence of the present invention, no such dwell period or pause and manual rotation are necessary to relocate the nose end  30  of the tab  26 , as the rotation of the rivet island  46  of the tab  26  about the rivet  28  occurs naturally with the lifting of the left end  32  of the tab  26 . 
     As the force from the nose end  30  of the tab  26  migrates towards the tear panel  20 , fracture of the third segment  90  of the score line  22  propagates towards the terminal end  22   b  of the score line  22  and the tear panel  20  is forced downwardly into a headspace of the beverage container. See, e.g.,  FIG. 8 . As the pour opening  20 ′ is fully developed, the hinge segment  25  forms between the terminal end  22   b  of the score line  22 , past the rivet  28 , and ends at the intersection of the second segment  86  and the third segment  90 . See, e.g.,  FIG. 9 . Thus, the hinge segment  25  extends from the fourth quadrant, through the third quadrant, and terminates in the second quadrant where the fracture in the third segment  90  of the score line  22  began. 
     Again, it is further contemplated that all or some portion of the second segment  86  of the score line  22  will not fracture during the opening sequence. Thus, there can be a length of unfractured score line  22  connecting the now fractured first segment  70  of the score line  22  with the now fractured third segment  90  of the score line  22 . 
     The tab  26  may have one or more features that assist in fracturing the score line  22 . 
     For example, typically, the rivet island  46  has a rivet hole therein through which the rivet  28  passes to attach the tab  26  to the remaining portion of the center panel  12 . The rivet hole is located in the center of the rivet island equidistant from the portions of the legs of the void region  48  that extend along opposing sides of the void region  48 . In one embodiment of the present invention, the rivet hole is offset from this center location wherein it favors one side of the rivet island  46  at the expense of the other. In other words, the rivet hole is located nearer one the legs of the void region  48 . 
     In one embodiment, the rivet hole is placed to increase an overlap of the nose end of the tab  26  with the score line  22 . 
     In the embodiment illustrated, the rivet hole is offset towards the longer of the opposing legs. 
     Additionally, the nose end  30  of the tab  26  may have a cleat  110  (see  FIGS. 6 and 11 ). The cleat  110  is offset from a center line of the tab  26  defined by a segment of the first axis  72  as illustrated. Thus, the cleat  110  is located in the third quadrant of the can end when the tab  26  is in the stowage position and initial score line opening position as illustrated, and the tab  26  does not exhibit bilateral symmetry. 
     The cleat  110  is generally located in or at the nose end  30  of the tab  26  (see  FIG. 2 ), preferably within the arc area of the circular arc  300  described above, more preferably offset from the center line of the tab  26  and within the third quadrant of the can end  10  when the tab  26  is in the stowage position and initial score line opening position (see  FIGS. 6, 11 and 12 ). 
     Structurally, the cleat  110  comprises a compressed portion of the curled portion  38  of the tab  26  and a substantially V-shaped crevice on an upper surface of the tab  26 . Thus, the cleat  110  has an upper surface exhibiting a V-shaped crevice and a lower surface extending downwardly towards the public side  34  of the tear panel  20 . 
     The forming of the cleat  110  also forces the curled portion of the tab  26  radially outwardly relative to the center of the rivet  28 . Thus, the cleat  110  extends radially outwardly from the nose end  30 . This effectively lengthens the tab  26  at the cleat  110  wherein the cleat  110  extends farther outwardly than remaining portions of the nose end  30  of the tab  26 . 
     An alternative embodiment is illustrated in  FIG. 13 . The opening of the can end  10  of this embodiment is actuated in an identical manner to that of the previous embodiments. The lift end  32  of the tab is lifted straight upwardly from the center panel  12  by the user without consciously rotating the tab about the rivet  28 . A vent region of the score line  22  opens adjacent the rivet  28  wherein a pressure is safely released from the container as the first segment  70  of frangible score breaks or fractures. 
     The chief difference between the embodiment of  FIG. 13  and the embodiment of  FIG. 11  is as follows. Subsequent to initial venting of the pressure within the container, fracture of the score line  22  is bi-directional, continuing simultaneously in a first path along the first segment  70  of frangible score towards the second segment of frangible score  86  and in a second path along a bypass segment  114  of frangible score to the third segment  90  of frangible score. Fracture of the third segment  90  continues, and the tear panel  20  is deflected inwardly into the container just as in the description of the previous embodiments. The non-frangible hinge  25  is located similarly to prior can ends. 
     An alternative embodiment is illustrated in  FIG. 14 . Again, the opening of the can end  10  of this embodiment is actuated in an identical manner to that of the previous embodiments. The lift end  32  of the tab is lifted straight upwardly from the center panel  12  by the user without consciously rotating the tab about the rivet  28 . A vent region of the score line  22  opens adjacent the rivet  28  wherein a pressure is safely released from the container as the first segment  70  of frangible score breaks or fractures. 
     The score line  22  of this embodiment is designed differently than the previous embodiments. Here, the non-frangible hinge segment  25  is located on an opposite side of the rivet  28  than the embodiment of  FIG. 13 . 
     In this embodiment, again, upon lifting of the lift end  32  of the tab  26 , a vent region is formed adjacent the rivet  28 . Fracture of the score line  22  of this embodiment is bi-directional as in the previous embodiment; however; there is no fork in the score line  22  in this embodiment. Using a clock-like reference, the fracture of the first segment of frangible score  70  proceeds in a first direction towards the second segment  86  of frangible score to form a pressure equalization port. Simultaneously, fracture of the third segment  90  of frangible score proceeds in an opposite direction. As lifting of the lift end  32  of the tab  26  continues, the tab  26  rotates about the rivet  28  the manner described above relative to the previous embodiments; the fracture of the third segment  90  of frangible score continues; and the tear panel  20  is deflected into the container to form the pour opening. 
     In the example illustrated in  FIG. 14 , the fracture of the first segment  70  proceeds in a clockwise-like direction, while the fracture of the third segment  90  proceeds in a counterclockwise-like direction. 
     It should be noted further that the inventors have produced containers having vent regions  104 , pressure equalization ports  106 , and pour openings  20 ′ located and sized according to the description set forth herein. The pressure equalization ports  106  of these containers improved the flow of beverage from the container such that a laminar flow of the beverage was achieved without unacceptable ‘glug”. 
     The terms “first,” “second,” “upper,” “lower,” “top,” “bottom,” etc. are used for illustrative purposes relative to other elements only and are not intended to limit the embodiments in any way. The term “plurality” as used herein is intended to indicate any number greater than one, either disjunctively or conjunctively as necessary, up to an infinite number. The terms “joined,” “attached,” and “connected” as used herein are intended to put or bring two elements together so as to form a unit, and any number of elements, devices, fasteners, etc. may be provided between the joined or connected elements unless otherwise specified by the use of the term “directly” and/or supported by the drawings. 
     While the specific embodiments have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying Claims.