EP2557051A1

EP2557051A1 - Can end

Info

Publication number: EP2557051A1
Application number: EP12177986A
Authority: EP
Inventors: Thomas Glenn Crothers
Original assignee: DRT Mfg Co
Current assignee: DRT Mfg Co
Priority date: 2011-08-09
Filing date: 2012-07-26
Publication date: 2013-02-13
Also published as: CN102951343A; US20130037542A1

Abstract

A can end (10) comprises a center panel (14) having a diameter, a geometric center (16) lying on a transverse axis of symmetry (X-X) of the center panel (14), a score line (18) defining a periphery of a tear panel (20), a lift tab (22), and a rivet (28) attaching the lift tab (22) to the center panel (14) and permitting a nose portion (24) and lift (26) portion of the lift tab (22) to pivot out of the plane of the center panel (14), the rivet (28) located on a first side (30) of the transverse axis of symmetry (X-X) and the tear panel (20) located substantially on a second side (31) of the transverse axis of symmetry (X-X) opposite the first side (30).

Description

FIELD

This invention relates generally to ends of beverage cans, and more particularly to an improved center panel, tear panel, and lift tab configuration for a can end.

BACKGROUND

A can, for example a beverage can, typically includes a generally cylindrical can body having a side wall and a bottom wall. A can end is attached to an upper end of the side wall of the can body. The can end comprises a center panel, a score line defining a periphery of a tear panel, and a lift tab having a nose portion and a lift portion opposite the nose portion. A rivet attaches the lift tab to the center panel and hermits the nose portion and lift portion to pivot out of the plane of the center panel. The nose portion is configured to contact the tear panel as the lift portion is lifted so as to rupture the score line and swing the tear panel out of the plane of the center panel, thereby defining a tear panel aperture or opening for accessing the contents of the can.
The size of the tear panel aperture in the can end affects the flow rate, pourability and drinkability of the contents of the can. Generally, for a larger tear panel aperture the flow rate is greater and one is able to pour the contents from the can in a smoother manner. As the tear panel aperture decreases in size, fluctuations in flow rate begin to occur (known as "glugging"), and the amount of time required to reach the maximum flow rate increases, both of which are undesirable.
The trend is toward smaller can ends in order to decrease the costs of production. In can maker' terminology, can ends can vary in size from, for example, the larger 211 can end, down to, for example, the smaller 202 can end. The trend is towards 202 and even smaller can ends, such as 202 Super End ("202 SE"), 202 Container Developments Limited ("202 CDL"), 200, and 113 can ends.
Can ends have a center panel and a sloping circumferential outer wall. The circumferential edge of the sloping circumferential outer wall is crimped or otherwise attached to the upper edge of the side wall of the can body. The smaller sized can ends have a smaller diameter center panel. However, as the center panel of the can end decreases in diameter, there is less available area (square inches/square millimeters) from which to form the tear panel, resulting in a decrease in size of the tear panel aperture which generally causes the undesired flow properties discussed above.
Generally speaking, it may be desirable to have a tear panel aperture that is greater than 0.5 square inches (323 mm²) for satisfactory flow rate, pourability and drinkability. See U.S. Patent No. 5,711,448 . However, for 202 and smaller can ends, there was concern that the tear panel aperture would have to be smaller giving rise to concerns. But to overcome the problems created by such small tear panel apertures, it was suggested in U.S. Patent No. 7,594,585 to require that the aspect ratio (i.e., the ratio of the major axis of the tear panel aperture to the minor axis thereof) be held between 1.3 and 1.7. Limiting the aspect ratio in this manner, especially at the lower end, can be undesirable as the resulting can ends might present undesirable performance or aesthetic characteristics.

SUMMARY

have determined that it is possible to provide can ends with tear panel apertures that are larger than about 0.5 square inches (323 mm²) in small can ends, such as 202 can ends and smaller, while permitting (although not requiring) aspect ratios that can range to well below 1.3 so as to obtain the advantages of such larger tear panel apertures, but without the drawbacks imposed by limiting the tear panel aperture to the larger aspect ratios. To that end, and in accordance with the principles of the present invention, I have discovered that beneficial and acceptable can ends can be obtained by offsetting the rivet which attaches the lift tab to the center panel so that it is on one side of a transverse axis passing through the geometric center of the can end, with the tear panel being substantially on the opposite side of that axis. Such positioning maximizes the available area for the tear panel and hence tear panel aperture. As a result, it is possible to provide 202 and smaller can ends with the desired 0.5 square inches (323 mm²) or larger tear panel aperture while achieving the desired dynamics by which to open and drink from the can having that can end. At the same time, if desired, it is possible to utilize tear panel apertures having aspect ratios less than 1.3. In some embodiments of a 202 or smaller can end, for example 202 SE or 202 CDL can ends, the aspect ratio of the tear panel aperture advantageously ranges from about 1.11 to about 1.60, and the area of the tear panel aperture advantageously ranges from about 0.54 square inches (348 mm²) to about 0.77 square inches (496 mm²). In addition, by having the tear panel extend to the same side of the transverse axis of symmetry as the rivet, the venting of the can is better during pouring thus improving the flow rate of the beverage from the can.
By virtue of the foregoing, there is thus provided can ends with tear panel apertures that are larger than about 0.5 square inches (323 mm²) in small can ends, such as 202 can ends and smaller, while permitting aspect ratios that range to below 1.3 so as to obtain the advantages of such larger tear panel apertures, but without the drawbacks imposed by limiting the tear panel aperture to the larger aspect ratios. These and other advantages of the present invention will be apparent from the accompanying drawings and description thereof.

DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description of the embodiment given below, serve to explain the principles of the present invention.
Fig. 1 is a top view of an exemplary embodiment of a can end incorporating the offset rivet of the present invention.
Fig. 2 is a cross-sectional view taken along line 2-2 in Fig. 1.
Fig. 3A is a schematic top view of an exemplary embodiment of the tear panel apertures for the can end of Fig. 1 having an aspect ratio of about 1.11 and an area of about 0.54 square inches.
Fig. 3B is a schematic top view of another exemplary embodiment of the tear panel aperture for the can end of Fig. 1 having an aspect ratio of about 1.60 and an area of about 0.77 square inches.

DESCRIPTION

Referring first to Figs. 1 and 2, a can end 10, for example a 202 SE or 202 CDL can end, has a sloping side wall 12 and a center panel 14. Though a 202 SE or 202 CDL can end is illustrated in the drawings, the invention can be practiced with any 202 can end or smaller can end, such as 202, 202 SE, 202 CDL, 200, and 113 can ends. A first transverse axis of symmetry X-X and a second transverse axis of symmetry Y-Y, perpendicular to the first transverse axis of symmetry, define a geometric center 16 of the can end 10. The can end 10 also has a longitudinal axis of symmetry Z-Z. A score line 18 defines a periphery of a tear panel 20. A lift tab 22 has a nose portion 24 and a lift portion 26 opposite the nose portion 24. The nose portion 24 is configured to contact the tear panel 20 as the lift portion 26 is lifted so as to rupture the score line 18 and swing the tear panel 20 out of a plane of the center panel 14. A tear panel aperture 21 is thereby defined for accessing the contents of a can to which the can end 10 is attached. A rivet 28 attaches the lift tab 22 to the center panel 14 and permits the nose portion 24 and lift portion 26 to pivot out of the plane of the center panel 14.
The rivet 28 is located on a first side 30 of the transverse axis of symmetry X-X, and the tear panel 20 and hence tear panel aperture 21 is located substantially on a second side 32 of the transverse axis of symmetry X-X, opposite the first side. For example, the center 34 of rivet 28 is offset by a distance d from the transverse axis of symmetry X-X. This configuration readily provides a tear panel apertures 21 having an area greater than about 0.5 square inches, with a center panel 14 having an area no greater than the center panel of a 202 can end such as for 202, 202 SE, 202 CDL, 200, and 113 can ends, by way of example.
Referring to Figs. 1-3B, and in particular to Figs. 3A and 3B, the tear panel aperture 21 (the basic geometry of which is known to those skilled in the art), has a width dimension w and a height dimension h perpendicular to the width dimension w. A ratio of the width dimension to the height dimension (w/h) defines an aspect ratio of the tear panel aperture 2 1. The aspect ratio of the tear panel aperture 21 can range from about 1.11 to about 1.60. At the lower end of the aspect ratio spectrum of about 1.11, the tear panel aperture 21 1
is about 0.54 square inches. At the upper end of the aspect ratio spectrum of about 1.60, the tear panel aperture 21 is about 0.77 square inches. At both the lower and upper ends of the aspect ratio spectrum, and by way of example for 202 SE and 202 CDL can ends, the distance d of the rivet 28 from the geometric center 16 is about 0.1347 inches. The invention can be successfully practiced with other values of the distance d. As can be seen from Figs. 3A and 3B, an aspect ratio of about 1.11 produces a more "circular" tear panel aperture 21 (Fig. 3A), whereas an aspect ratio of about 1.60 produces a more "oblong" tear panel aperture 21 (Fig. 3B).
While the present invention has been illustrated by description of embodiments thereof and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of applicant's general inventive concept.

Claims

A can end (10) comprising a center panel (14) having a diameter, a geometric center (16) lying on a transverse axis of symmetry (X-X) of the center panel (14), and a score line (18) defining a periphery of a tear panel (20), a lift tab (22) having a nose portion (24) and a lift portion (26) opposite the nose portion (22), the nose portion (22) configured to contact the tear panel (20) as the lift portion (26) is lifted so as to rupture the score line (18) and swing the tear panel (20) out of a plane of the center panel (14), thereby defining a tear panel aperture (21) for accessing the contents of a can to which the can end (10) is attached, and a rivet (28) attaching the lift tab (22) to the center panel (14) and permitting the nose portion (24) and lift portion (26) to pivot out of the plane of the center panel (14), wherein the rivet (28) is located on a first side (30) of the transverse axis of symmetry (X-X), and the tear panel (20) is located substantially on a second side (32) of the transverse axis of symmetry (X-X) opposite the first side (30).
A can end (10) as claimed in claim 1, wherein the tear panel aperture (21) has a width dimension (w) and a height dimension (h) perpendicular to the width dimension (w), and a ratio (w/h)of the width dimension (w) to the height dimension (h) defines an aspect ratio of the tear panel aperture (21) and ranges from about 1.11 to about 1.60.
A can end (10) as claimed in claim 1 or claim 2, wherein the tear panel aperture (21) has an area greater than about 0.5 square inches.
A can end (10) as claimed in claim 3, wherein the tear panel aperture (21) has an area ranging from about 0.54 square inches to about 0.77 square inches.
A can end (1) as claimed in preceding claim, wherein the center panel (14) has an area no greater than a center panel of a 202 can end.
A can end (10) as claimed in any preceding claim, wherein configuring the tear panel (20) to extend to the first side (30) of the transverse axis of symmetry (X-X) provides for improved venting of the can during pouring the contents from the can thus improving the flow rate of the contents from the can.