Can end having a main score and a score extension

A beverage can end for seaming onto a can body may include a peripheral wall, a center panel, a tab attached to the center panel by a rivet (56), a tear panel (41b), a main reference line (RM), a transverse reference line (RT), and a score (31b). The score may include arcuate main score (31b) that defines a main portion of the tear panel (41b) and a score extension (32b) that defines a vent portion. The score may be configured such that actuation of the tab from its horizontal rest position to an intermediate position ruptures the main score portion (31b) to pivot the tear panel main portion (40b) about the hinge and further actuation of the tab by twisting from the intermediate position ruptures the score extension (32b).

TECHNICAL FIELD

The present invention relates to metal packaging, and more particularly to optionally vented openings in metal beverage can ends.

BACKGROUND

Aluminum beverage cans are produced in vast quantities. Conventional beverage cans include a one-piece, drawn and ironed body and an end that is attached to a flange of the can body by a double seam. A can end, in its unseamed state, has a peripheral curl for seaming to the can body flange, a wall extending from the curl (that is, a chuck wall), an annular bead (that is, a countersink), or like structure extending from the wall and a center panel.

Conventional center panels have a score that defines a tear panel and a tab that is attached to the center panel by a rivet. The score has first and second ends that define a hinge about which the tear panel actuates. In the vast majority of commercial ends, the hinge is not centered relative to the score and tear panel, but rather is located to a side. The score extends from its first end in front of the rivet about a curved path to its second end. Conventional large opening ends (LOE) have an elongated opening, as shown inFIG. 1A(Prior Art).

Commercial ends of the type shown inFIG. 1Aare opened only by lifting the heel of the tab to force the tab nose against the tear panel. The downward force initiates an initial venting, which is promoted by a check slot, and the downward force then displaces the tear panel and ruptures the remainder of the score to form an opening.

Pouring from conventional beverage cans creates unsteady state flow or “glugs,” as described in U.S. patent application Ser. No. 09/857,145, which is assigned to the assignee of the present invention.

U.S. Pat. Nos. 6,354,453; 6,079,583; 5,555,992; 5,011,037; and 3,977,561 disclose can ends that have been purported to create a vent after opening. There is a need for improved can end configurations that promote venting after opening of the tear panel.

SUMMARY

A beverage can end, a method of opening a beverage can end, and a system for forming a score in a beverage can end are disclosed. A beverage can end for seaming onto a can body may include a peripheral wall, a center panel, a tab attached to the center panel by a rivet, a tear panel, a main reference line, a transverse reference line, and a score. The tear panel may include (i) a main portion capable of pivoting about a hinge and (ii) a vent portion. The main reference line may bisect the tear panel main portion and may extend through the rivet, the hinge being offset relative to the main reference line. The transverse reference line may be perpendicular to the main reference line and may extend through the rivet, the main portion of the tear panel being located in front of the transverse reference line. The score may include arcuate main score that defines the main portion of the tear panel and a score extension that defines the vent portion.

Preferably, the score extension defines an arc that generally corresponds to the path of the tab when twisted in the further actuation from the intermediate position, such as a curved profile. Also, the score may be configured such that the actuation from the intermediate position is optional. Preferably, the main portion of the tear panel is elongated in a transverse direction and has an aspect ratio of between 1.3 and 1.7.

The main reference line and the transverse reference line preferably divide the center panel into first and second front quadrants and first and second rear quadrants, the score extends (i) from the score first end in the first front quadrant across to the main reference line near the rivet to extend into the second front quadrant, (ii) in an arcuate path in the second front quadrant, (iii) across the main reference line near the front-most portion of the center panel, (iv) in an arcuate path in the first front quadrant, and (v) to an intermediate point located in the first front quadrant and defining an end of the hinge opposite the score first end.

The score extension extends from the intermediate point across the transverse reference line into the first rear quadrant. The hinge is defined between the score first end and an intermediate point on the score, which is at the base of the score extension. Preferably the score extension is no longer than three times the length of the hinge, and even more preferably the score extension is no longer than two times the length of the hinge.

A first end of the score (i) may define one end of the hinge and (ii) may be located on the hinge-side of the main reference line and in front of the transverse reference line. A second end of the score (1) may define one end of the score extension and (ii) may be located on the hinge-side of the main reference line and to the rear of the transverse reference line. The score may be configured such that actuation of the tab from its horizontal rest position to an intermediate position ruptures the main score portion to pivot the tear panel main portion about the hinge, and further actuation of the tab by twisting from the intermediate position ruptures the score extension. The score extension may optionally define an arc that generally corresponds to the path of the tab when twisted in the further actuation from the intermediate position.

A method of opening a beverage can end may include the steps of providing a beverage can including a can body and an end attached to the can body by a double seam; lifting a heel of the tab from its initial, horizontal position; and twisting, after the lifting step, the tab to rupture an extension of a score. The can end may include a peripheral wall, a center panel, and a tab attached to the center panel by a rivet. The center panel may include a tear panel that is formed by a score and may define a main reference line that bisects a main portion of the tear panel. Lifting a heel of the tab from its initial, horizontal position may force a nose of the tab against the tear panel until the score ruptures and the tear panel main portion pivots about a hinge that extends from a first end of the score. The first end of the score may be located in front of the main reference line and on the hinge-side of a transverse reference line. The score may be configured such that actuation of the tab from its horizontal position to an intermediate position ruptures the main score portion to open the tear panel main portion and further actuation of the tab by twisting from the intermediate position ruptures the score extension to open the panel vent portion. The score extension may optionally define an arc that generally corresponds to the path of the tab when twisted in the further actuation from the intermediate position.

A system for forming a score in a beverage can end may include an upper score cap having a main score protrusion and a score extension protrusion and a lower score cap having an uninterrupted anvil surface extending at least to the corresponding location of the score extension protrusion of the upper score cap. The upper score cap and the lower score cap may be configured to press together such that the main score protrusion forms a main score in the beverage can end and the score extension protrusion forms a score extension in the beverage can end. The main score and the score extension may be configured such that actuation of a tab coupled to the can end from its horizontal position to an intermediate position ruptures the main score portion to open a tear panel main portion and further actuation of the tab by twisting from the intermediate position ruptures the score extension to open a panel vent portion. The score extension may optionally define an arc that generally corresponds to the path of the tab when twisted in the further actuation from the intermediate position.

These and various other advantages and features are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there are illustrated and described preferred embodiments of the invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Referring toFIG. 1A(prior art), a prior art beverage can1includes a can body2and a conventional large opening end (LOE)3. The can end3is attached to the can body2by a conventional double seam4. The can end3includes a center panel5. The center panel5has a score6that defines a tear panel7and a tab8athat is attached to the center panel5by a rivet8b. When the tear panel7is actuated, the score6defines an opening9through which the contents of the can1may be poured.

Referring toFIG. 2, a beverage can10illustrating a first embodiment of the present invention includes a can end14aattached to a can body12. The can body12preferably is formed of aluminum by a drawing and ironing process. The can end14ashown inFIG. 2is preferably is attached to can body12by a conventional double seam16.

The can end14ahas a generally circular shape with a rivet56located at or near the center of the can end14a. A chuck wall22extends inwardly and downwardly from seam16to an annular bead or countersink24. Countersink24connects the center panel26and the chuck wall22, extending downwardly into the chamber of the can body and away from the center panel26. The can end14amay be formed of a shell having any configuration, several of which are currently known. Reference numeral20inFIG. 2is used to illustrate the position of a portion of the curl of the unseamed can end. Can end14aincludes a score30aformed on center panel26, as described more fully below.

The first embodiment of the score (30a) is employed inFIG. 2to illustrate the combination of the can end with the can body.FIG. 3depicts a top view of a portion of a can end14baccording to a second embodiment of the present invention. End14bis illustrated in its unseamed state, and it is understood that the present invention encompasses can ends that are unseamed, seamed can ends, and the combination of a seamed can end and can body.

End14bincludes a center panel26having a score30b. Score30bincludes main score31band a score extension or vent score32b, which scores define a displaceable tear panel40bhaving a main portion41band a vent portion42b. To aid in the description of the location of portions of the score30b, a main reference line RMis defined as bisecting the main portion41bof the tear panel40band extending through the center of the rivet56. A transverse reference line RTis defined as perpendicular to the main reference line RMon the center panel26and extending through the center of the rivet56. For tear panels having a main portion that is asymmetrical (not shown), line RMmay be drawn through the rivet to divide the area of the main portion of the tear panel into equal areas. The transverse reference line RTdefines the front and rear directions or locations. The side of the transverse reference line RTon which main portion41bof tear panel40bis located is referred to as the front of can end14b, and the opposing side is referred to as the rear. The reference lines RMand RTform first and second front quadrants Q1and Q2and first and second rear quadrants Q3and Q4. When the front of the can end14bis depicted below the rear of the can end14bas shown inFIG. 3, Quadrants Q1and Q3are located on the left side (also referred to as the hinge side) of the main reference line RMand quadrants Q2and Q4are located on the opposing right side of the main reference line RM. In this way, the transverse reference line RTdefines directions left and right.

The shape and location of the main score31brelative to the main reference line RMand the transverse reference line RTwill now be described. Main score31bextends from a first end34of main score31b, which preferably is located to the front and side of the rivet56in the front left quadrant Q1. Main score31bextends across main reference line RMnear and in front of the rivet56into front right quadrant Q2in an arcuate path. A check slot35, which temporarily stops or inhibits the opening of the main score31bnear the rivet56to allow for initial venting of the beverage can10, may be located in the main score31bnear the rivet56. Accordingly, a portion of score31bnear end34functions as a conventional vent.

Past the check slot35, the main score31bcontinues in an arcuate path through Q2, the extent of which defines a side of the main portion41bof the tear panel40b, and again crosses the main reference line RMand into the front left quadrant Q1near the chuck wall22and near the front-most portion of the center panel26. In the embodiment shown inFIG. 3, the main score31bcontinues from the front of center panel26through the front left quadrant Q1in an arcuate path until the main score31bapproaches and extends to an intermediate point36b. Preferably, intermediate point36bis located in the front left quadrant Q1on the front side of the transverse reference line RTand on the same side of the main reference line RMas the score first end34. Because main score31bextends toward main reference line RMafter forming the left-most portion of main panel portion41b, and score extension31bextends from intermediate point36bon a curved path that has a leftward component (as viewed inFIG. 4A), intermediate point36bis formed on a peninsula-like protrusion that forms a point and roughly triangular shape.

A hinge37is defined between the score first end34and the intermediate point36b. Hinge37defines the boundary of main portion41bof tear panel40band defines the structure about which the main portion41bof the tear panel40bpivots when the tear panel40bis opened. In the first, second, and third embodiments shown inFIGS. 2 through 5B, the hinge37is located on the front side of the transverse reference line RTand on the hinge side (also the left side in the figures) of the main reference line RMin quadrant Q1. While hinge37has been described in relation to the first end34and the intermediate point36bof the second embodiment, it will be appreciated that in the first and third embodiments, the hinge37extends from the first end34to the intermediate points36a,c, respectively.

Again referring toFIG. 3, a score extension32bextends from intermediate point36b. Score extension32bextends towards the rear of the can end14bfrom the intermediate point36bpast the transverse reference line RTand into the rear left quadrant Q3, without crossing the main reference line RM, to terminate at a second end38of the score31b. As shown, the score extension32bmay have a hook-shape or curvature.

FIG. 3also shows an anti-fracture score33bextending along the main score31b. The anti-fracture score33bpreferably extends along main score31band/or the score extension32band is offset from the main score31band/or the score extension32b. All scores described herein may be formed by conventional methods. Preferably, the main portion41of tear panel40has the dimensions of conventional large opening ends configured as well-known DRT or Stolle-style configurations.

FIG. 4Ashows combination can body12and can end14with the score configuration ofFIG. 3. A tab50for opening the tear panel40bis attached to the center panel26by rivet56. Tab50includes a heel52at its rear end and a nose54at its front end. When the tear panel40bis actuated, score30bdefines a portion of the main opening28(shown inFIG. 4B) through which the contents of the can10may be poured, and at least a portion of a vent opening29(shown inFIG. 4C) through which air can flow into the can10to allow for faster and smoother pouring of a beverage through the main opening28. Hinge37defines another portion of the boundary of main opening28.

As shown inFIGS. 3, 4A, 4B, and 4C, score extension32bpreferably is curved to approximately follow an arc defined by the actuation of tab50, as explained more fully below. In this regard, the score extension32bmay have a radius that is approximately equal to or slightly larger than the radius of the arcuate path of the leading edge58(best shown in FIG.4C) of the tab50. For example, the score extension32bmay be formed of a single or gradually changing arcs that are no greater than about 130% of the radius of the arc of tab actuation, preferably no greater than about 120%, more preferably less than about 110% of the radius of the arc of tab actuation. In this regard, the arc of the tab actuation may be defined as the movement in space of the outermost portion of tab50as its is twisted from its intermediate position ofFIG. 4Bto its actuated position ofFIG. 4C. The arc preferably is defined in the plane of center panel26. Also, score extension32bpreferably is no longer than three times the length of the hinge, and more preferably no longer than two time the length of the hinge. The present invention is encompasses other shapes of the score extension.

FIG. 5Aillustrates a first embodiment of the score30a(shown inFIG. 2). First embodiment score30aincludes a main score31aand a score extension32a, both formed in the center panel26. Scores31aand32adefine a displaceable tear panel40ahaving a main portion41aand a vent portion42a. Tab50is attached to center panel26by rivet56. The description of main portion41aand tear panel40ais the same as that for second embodiment main panel portion41b. Second embodiment score extension32aextends from an intermediate point36aon the score.

First embodiment main score31ais as described for second embodiment main score31bwith respect to its shape from end34(not shown inFIG. 5Abecause end34is below tab50) through quadrant Q2. Main score31aextends from quadrant Q2in its arcuate path through quadrant Q1to define the left-most part of main panel portion41a. Main score31aextends around the leftward-most part of main panel portion41aand extends rearward, then extends rearwardly and rightwardly with only a slight inward curvature (that is, convex when viewed from the hinge-side of the end). Intermediate point36ais formed on the inwardly bowed portion of the score. In embodiments in which the location of the intermediate point it is unclear from the shape of the score, the intermediate point may be defined as the portion of the score the forms the end of the hinge opposite end34. Intermediate point36apreferably is in quadrant Q1—forward of transverse line RTand on the left or hinge side of main reference line RM.

Score extension32aextends towards the rear of the can end14afrom the intermediate point36apast the transverse reference line RTand into the rear left quadrant Q3, without crossing the main reference line RM. Score extension32aterminates at a second end38of the score30a. As shown, the score extension32amay have a hook-shape or curvature that extends inwardly toward main reference line RM. Preferably, score extension32ahas an arcuate shape as described above with respect to second embodiment score extension32b.

Preferably, the upper portion (that is, distal from intermediate point36a) has curvature and dimensional relationships that are as described for second embodiment score extension32b, such that (for example) the tail portion of score extension32ahas a radius that is approximately equal to or slightly larger than the radius of the arcuate path of the leading edge58of the tab50, and a length as described above.

FIG. 5Bdepicts a third embodiment of the score30con a can end14c. Third embodiment score30cincludes a main score31cand a score extension32cand is formed in the center panel26. Main score31cand score extension32cdefine a displaceable tear panel40chaving a main portion41cand a vent portion42c. Tab50is attached to center panel26by a rivet56. The description of main portion41atear panel40ais the same as that for second embodiment main panel portion41bexcept for intermediate point36cand the portion of score31cnear intermediate point36c. Third embodiment score extension32cextends from an intermediate point36con the score.

Third embodiment main score31cis as described for second embodiment main score31bwith respect to its shape from end34(not shown inFIG. 5Bbecause end34is below tab50) through quadrant Q2. Main score31cextends from quadrant Q2in its arcuate path through quadrant Q1to define the left-most part of main panel portion41c. Main score31cextends around the leftward-most part of main panel portion41cand extends rearward, then extends rearwardly and rightwardly with an inward curvature (that is, convex when viewed from the hinge-side of the end) to form a waist. Intermediate point36cis formed on the inwardly bowed portion or waist portion of the score. Intermediate point36cpreferably is in quadrant Q1—forward of transverse line RTand on the left or hinge side of main reference line RM.

Score extension32c, from intermediate point36c, extends away from main reference line RMand toward the rear of the can end14c, thereby forming a protruding portion of the center panel and the waist on which intermediate point36cis defined. Score extension32ccontinues to extend past the transverse reference line RTand into the rear left quadrant Q3, without crossing the main reference line RM. Score extension32cterminates at a second end38of the score30c. As shown, the score extension32chas a hook-shape or curvature that extends inwardly toward main reference line RM. Preferably, score extension32chas an arcuate shape as described above with respect to second embodiment score extension32c.

Preferably, the curvature of the upper portion of score extension32c(that is, distal from intermediate point36c) has curvature and dimensional relationships that are as described for second embodiment score extension32b, such that (for example) the tail portion of score extension32chas a radius that is approximately equal to or slightly larger than the radius of the arcuate path of the leading edge58of the tab50, and a length as described above.

The main scores31a,b,cof the three embodiments shown inFIGS. 2 through 5B(the use of more than one reference letter after a reference numeral will be used in the description to indicate that the text refers to the embodiments corresponding to the reference letters) may have the same depth and cross-sectional shape as the score6in a conventional large opening end3(shown inFIG. 1A). For example, the score residual for the main score31bmay be approximately 0.0034 to 0.0043 inches. Alternatively, the three embodiments of the main score31a,b,cmay have a thicker score residual than the score6in a conventional large opening end3(e.g., for increased score strength).

In the embodiments shown in figures, all of the main scores31a,b,cand the main portions41a,b,cof the tear panels40a,b,cdo not extend rearward of the transverse reference line RT. The present invention is not limited to such structure, but rather the claims provide the full measure of the scope of the present invention.

The score extensions32a,b,cpreferably have the same depth and cross-sectional shape as the main score31a,b,c. In some embodiments, including for example, when it is desired to increase the pressure at which the score30a,b,cbursts, the score extensions32a,b,cmay have a thicker score residual than main score31a,b,c.

The score30a,b,cmay include a second conventional check slot at or near the intermediate point36a,b,cto help strengthen the main score31a,b,cand/or the score extension32a,b,c, which may enhance (that is, enable higher) the internal pressure performance or rating of the can. The score30may include a gap (not shown) at or near the intermediate point36to help strengthen the main score31and/or the score extension32for enhancing pressure performance or rating. The gap preferably is a portion of center panel26that has its full thickness such that portions of the score are space apart.

To describe the operation of the can ends described herein, and to explain the method steps according to an aspect of the present invention,FIGS. 4A, 4B, and 4Cillustrate the opening and venting function of end14b. WhileFIGS. 4A through 4Cillustrate the second embodiment end14b, the description of the opening and venting process provided in the description also applies to the opening and venting of the first embodiment (shown inFIGS. 2 and 5A) and the third embodiment (shown inFIG. 5B). Accordingly, starting with the can end14bin an un-actuated, at-rest state, in which score30bis intact and tab50is approximately parallel to a plane defined by center panel26or the upper rim of double seam16, as shown inFIG. 4A, an end user begins the opening process by lifting the tab heel52. In response, the tab50pivots about rivet56and induces deflection of the rivet56to force tab nose54against the main panel portion41bwhen the tab is inclined approximately 20 degrees from the horizontal.

Most scores are configured such that main score31bruptures first in a short region near the rivet56and near first score end34, and check slot35temporarily stops or slows propagation of the rupture of main score31b. As the end user continues to lift tab heel52, the force applied by the nose54against the main panel portion41bincreases until the rupture of the main score31bbegins (or check slot35is overcome, which occurs typically when tab50is inclined at approximately 70° relative to the center panel26or the rim of seam16or the horizontal) and then the rupture of the main score31bpropagates about the main portion41bof the tear panel40buntil score propagation stops at or near intermediate point36b.

FIG. 4Bdepicts can end14bin a partially actuated state, upon completion of the first stage of opening of the score30b. The main portion41bof the tear panel40bhas pivoted about the hinge37to form the main opening28. Tab50is generally upright such that tab50is oriented approximately 90° from its rest position and relative to center panel26or the rim of seam16. A horizontal line LTin the plane defined by the tab50, running the length of the center of the tab, is approximately perpendicular to the transverse reference line RT.

After the can end14bhas been positioned in the partially actuated state shown inFIG. 4B, a user may pour a beverage through the main opening28in the conventional way. If a user is does not understand or appreciate the additional venting structure42band how to actuate the second stage of the opening process, or desires not to use the additional venting structure or capabilities, the user need do nothing more except pushing heel52back to its at-rest position. Thus, the user may use end14bin a conventional way, thereby ignoring the additional venting capabilities of the can end14b. Alternatively, the user may (optionally) perform additional actuation of the tab50to open a vent opening29for faster and smoother pouring of a beverage through the main opening28. Opening the vent opening29may allow a user to pour a beverage through the main opening28more quickly, in many embodiment approximately twice as quickly, compared with leaving the vent opening29closed.

FIG. 4Cdepicts the can end14bin a fully actuated, vented state. To perform the second opening stage to get end14bto its fully actuated state, a user grasps and twists the tab heel52to create a moment about the horizontal line LT. In the orientation of the Figures, the user pivots tab50clockwise (roughly) about the horizontal line LTto rupture score extension32. More specifically, the leading edge of the tab50engages the vent portion42bof the tear panel40binitially at or near the hinge37under moment from the user's twisting until the score extension32bruptures at or near the intermediate point36b. The rupture then propagates along the score extension32btoward the second end38of the score30b.

The displacement of the vent portion42from the plane of the center panel26to create the vent opening29provides venting (an opening through which air can flow into can10) during pouring of a beverage through the main opening28, which may reduce “glugging” and which may provide relatively smooth flow or diminish the magnitude of flow rate variations of the unsteady state flow of a beverage through the main opening28.

Referring toFIG. 1B(prior art), a prior art can end14fincludes a circular center panel26f. A score30fand a vent channel32fare formed in center panel26f, and the score30fdefines a displaceable tear panel40f. The can end14fis produced by Ball Corporation for Coors Brewing Company.

Referring toFIG. 6A, a graph60shows the weight of liquid poured from various can ends over time during an initial flow rate period (that is, after which the flow rate slows down once most of the liquid has already poured out of the can). The four score shapes tested to produce graph60are score6(FIG. 1A, Prior Art), score30a(FIG. 5A), score30c(FIG. 5B), and score30f(FIG. 1B, Prior Art), which are shown respectively as lines61,62,63, and64. The weight of liquid poured over time out of each of the can ends shows a comparison of these four score shapes in terms of which shapes allow the fastest peak pouring of liquid through the can end.

As can be seen in graph60, lines62and63(representing inventive scores30aand30c, respectively) had the highest flow rates. Line64(representing score300and line61(representing score6) had lower flow rates. Comparing the performance of the different score shapes and venting structures, it can be seen from the graph60that the two lift-and-twist score embodiments30aand30chad substantially faster flow rate performance than the conventional large opening end score6and the conventional large opening end score30fwith a vent channel. The average flow rates and projected time to pour 12 oz (at a constant flow rate) that can be calculated from graph60are shown below in TABLE 1.

Referring toFIG. 6B, a graph70shows the flow rate of liquid poured from a can end openings versus time. Each point on graph70shows the average flow rate of liquid poured during the previous 1.5 seconds such that graph70represents a running 1.5-second average flow rate of liquid poured. The initial portion of graph70correlates to the slope of the curves shown in graph60, but graphs70shows data over a longer period.

The four score shapes tested to produce graph70are the same four score shapes tested to produce graph60, which are: prior art score6(FIG. 1A), score30a(FIG. 5A), score30c(FIG. 5B), and prior art score30f(FIG. 1B), which are shown respectively as lines71,72,73, and74. The flow rate of liquid poured out of each of the can ends can allow a comparison of which score shapes and venting structures allow the fastest total pouring of liquid through the can end.

As can be seen in the graph70, lines72and73(representing scores30aand30c, respectively) had the highest initial running average flow rates. Line74(representing prior art score30f) and line71(representing prior art score6) had lower initial flow rates. Comparing the performance of the different score shapes and venting structures, it can be seen from the graph70that the inventors' two lift-and-twist score embodiments30aand30chad substantially faster initial running average flow rate performance than the conventional LOE score6and the conventional LOE score30fwith a vent channel. Although the running average flow rates of lines72and73(corresponding to embodiments of the present invention) dropped below that of lines71and74(prior art LOE scores) at approximately 4 seconds, this is because by 4 seconds, most of the liquid has already been poured out of scores30aand30c, so the last ounce or two of liquid pours out at a slower rate.

To understand how quickly the 12-oz volume is poured out of the various score types, the area under each of the curves71-74can be calculated. As can be seen from graph70, the area under curves72and73are farthest to the left of graph70, which means that the volume is poured out of scores30aand30cat an earlier point in time compared to the LOE scores. It can be seen from graph70that curves72and73drop below 0.5 oz/s at approximately 5 seconds, at which point there is less than 1 oz of liquid remaining in the can, while curve74drops below 0.5 oz at approximately 6 seconds, and curve71drops below 0.5 oz at approximately 8 seconds. Therefore, approximately the first 11 oz of liquid in cans having the lift-and-twist scores (curves72and73) can be poured out 1 second faster than the conventional LOE score with a conventional venting structure (curve74) and 3 seconds faster than the conventional LOE score alone (curve71).

The two lift-and-twist score embodiments30aand30cdepicted inFIGS. 5A and 5Bwere also tested for score performance. The first set of tests evaluated the break force and the tear force for each score design, using a score30aor30cresidual of approximately 0.003 inches. Five cans of each score design were used for each test. The break force is the force required to open the part of the main score31aor31cnear the rivet56, before the check slot35, to allow for initial venting of the beverage can. The tear force is the force required to propagate the opening of the main score31aor31cto the intermediate point36aor36c, thereby creating the main opening28. For each can tested, the main score31aor31cresidual was approximately the same as the score extension32aor32cresidual, within a tolerance of ±0.0002 inches.

The average break force for the first embodiment score30awas 3.2 lbs, and the average break force for the third embodiment score30cwas 3.7 lbs, both of which are sufficiently low for a user to be able to comfortably perform initial opening (typically, a value under 4.5 lbs is acceptable). The average tear force for the first embodiment score30awas 3.8 lbs, and the average tear force for the third embodiment score30cwas 3.7 lbs, both of which are sufficiently low for a user to be able to comfortably propagate the opening of the main score31aor31cand create the main opening28(typically, a value under 5.5 lbs is acceptable).

The second set of tests evaluated the burst strength of each score design (this is a “loose buckle” test). Five cans of each score design were pressurized until part of the beverage can failed. The average pressure at which can ends including the first embodiment score30afailed was 73.2 psi, and the average pressure at which can ends including the third embodiment score30cfailed was 68.1 psi. For pasteurized products such as beer, it is preferable that a can end withstand an internal pressure of 80 psi. In order to improve the burst strength, the inventors surmise that it would be beneficial to modify the design of the first embodiment score30aand/or the third embodiment score30cusing one or more of the score-strengthening mechanisms discussed above.

All of the can ends in the second set of tests suffered “score burst,” rather than “peaking” of the can end. This means that the scores score30aor30cfailed (score burst) before countersink24inverted at a point that forms a peak (that is, peaking). Peaking is a more desirable can end failure mode than score burst, so in order to change the failure mode from score burst to peaking, the inventors surmise that is may be beneficial to modify the design of the first embodiment score30aand/or the third embodiment score30cusing one or more of the score-strengthening mechanisms discussed above.

A third set of tests evaluated the burst strength of three modifications of the first embodiment score30adepicted. The three modifications included score30residuals of approximately 0.003 inches, 0.004 inches, and 0.005 inches, respectively. Ten cans of each modification were pressurized until part of the beverage can failed and began to reduce the pressure inside of each can. The average pressure at which can ends of each respective modification failed was 87.9 psi, 96.3 psi, and 95.9 psi for respective score30fresiduals of approximately 0.003 inches, 0.004 inches, and 0.005 inches. Given that for pasteurized products such as beer, it is preferable that a can end withstand an internal pressure of 80 psi, each of these modifications of the score performed sufficiently.

Regarding the failure mode of each modification, with the first modification having a score30aresidual of approximately 0.003 inches, eight can ends suffered “score burst,” and two can ends suffered “peaking and leaking” of the can end (that is, leaking from the peak formed upon failure).

Regarding the second and third modifications having the score30aresiduals of approximately 0.004 and 0.005 inches, respectively, eight can ends of each modification suffered “peaking” of the can end (i.e., having the can end14ainvert or pop up, moving about a hinge approximately located at the peripheral curl20), and two can ends of each modification suffered “peaking and leaking” Conventional large opening ends such as the can end3depicted inFIG. 1Atypically have the same rate of peaking and leaking as the second and third modifications, so there is little significant burst strength performance loss in these can ends compared to conventional large opening ends.

Referring toFIGS. 7A, 7B, and 8, an upper score cap80a, suitable for use to form the first embodiment scores depicted inFIGS. 2 and 5A, includes a main score protrusion81a, a score extension protrusion82a, and an anti-fracture score protrusion83a, each of which extends from an anvil surface84a. The upper score cap80afurther defines a tear panel aperture85aand a tool attachment aperture86athat penetrates through the upper score cap80aapproximately perpendicularly to anvil surface84a.

An upper score cap80c, suitable for use to form the third embodiment scores depicted inFIG. 5B, includes a main score protrusion81c, a score extension protrusion82c, and an anti-fracture score protrusion83c, each of which extends from an anvil surface84c. The upper score cap80cfurther defines a tear panel aperture85cand tool attachment apertures86cthat penetrate through upper score cap80capproximately perpendicularly to anvil surface84c. A score cap (not shown in the figures) for the second embodiment score30bwould have the corresponding shape of score30blocated in the place on the cap similar to that shown inFIGS. 7A and 7B.

A lower score cap90, suitable for use to form either of the first or third embodiment scores depicted inFIGS. 5A and 5B, includes an anvil surface91that defines a plurality of tool attachment apertures92that penetrate through the lower score cap90approximately perpendicularly to anvil surface91.

The lower score cap90defines a location93, at which an aperture is located in a conventional lower score cap, but at which there is no aperture present in the lower score cap90, because the score extension protrusion82aor82cneed to mate with a flat portion of anvil surface91to properly form the respective first or third embodiment score extension30. To compensate for the absence of an aperture at location93, the lower score cap90includes an enlarged aperture at a location94(compared to a smaller aperture at location94in a conventional lower score cap), so that lower score cap90can be securely coupled to and/or removed from other components of can end score forming equipment.

The score extensions of the lift-and-twist embodiments of the can ends shown in the Figures may only require relatively minor modifications to existing shell press and conversion tooling, such as the modifications to the locations of the apertures92in the lower score cap90, to allow conventional shell press and conversion tooling to be used to produce the lift-and-twist embodiments of the can ends.

The foregoing description is provided for the purpose of explanation and is not to be construed as limiting the invention. While the invention has been described with reference to preferred embodiments or preferred methods, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Furthermore, although the invention has been described herein with reference to particular structure, methods, and embodiments, the invention is not intended to be limited to the particulars disclosed herein, as the invention extends to all structures, methods and uses that are within the scope of the appended claims. Further, several advantages have been described that flow from the structure and methods; the present invention is not limited to structure and methods that encompass any or all of these advantages. Those skilled in can end technology, having the benefit of the teachings of this specification, may effect numerous modifications to the invention as described herein, and changes can be made without departing from the scope and spirit of the invention as defined by the appended claims. Furthermore, any features of one described embodiment can be applicable to the other embodiments described herein. For example, any features or advantages related to the shape of the main score, score extension, and anti-fracture score with respect to discussion of a particular can end embodiment can be applicable to any of the other can end embodiments described herein.