Easy open container end with method of manufacture, and tooling

An easy open can end having shallow panel integrally formed in the tear away panel and a tab nose bead formed on the panel proximate the rivet, a method of further forming a can end to incorporate the aforedescribed features, and tooling for the further forming of the easy opening end.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to easy-open ends for product containers, 
particularly, beverage and beer cans. In particular, the present invention 
provides an improved method for forming easy-open ends, improved tooling, 
and an improved can end that demonstrates superior functionality, 
particularly in its opening characteristics. 
2. Prior Art 
Many metallic cans for holding beverages or other products are provided 
with easy-open can ends, wherein a pull tab attached to a tear strip that 
is defined by a score in the can end. The pull tab may be lifted and then 
pulled to provide an opening in the can end for dispensing the can's 
contents. For ecological and safety reasons, many regions require that the 
tear strip and attached pull tab be retained to the can end after opening. 
In order to meet these requirements, various designs have been suggested 
by the prior art for ensuring that the tear strip and pull tab do not 
become separated from the can end. Generally, the pull tab is retained on 
the can end by means of a rivet. Methods of forming a can end can be found 
in U.S. Pat. Nos. 4,465,204 and 4,530,631 both to Kaminski et al., and 
assigned to the assignee of the instant invention. These patents are 
incorporated by reference as if fully set forth herein. 
In the manufacture of an easy-open can end, a can end shell is first formed 
from a metal sheet product, preferably an aluminum sheet product. The can 
end shell is then transferred to a conversion press. In the typical 
operation of a conversion press, a can end shell is introduced between an 
upper tool member and a lower tool member which are in the open, spaced 
apart position. A press ram advances the upper tool member toward the 
lower tool member in order to perform any of a variety of metal forming 
operations such as rivet forming, paneling, scoring, embossing, tab 
securing, and final staking. After performing an operation, the press ram 
retracts until the upper tool member and lower tool member are once again 
in the open, spaced apart position. The partially converted shell is 
transported to the next successive tooling operation until an easy-open 
can end is completely formed and discharged from the press. As one shell 
leaves a given tooling operation, another shell is introduced to the 
vacated operation, thus continuously repeating the entire easy-open can 
end manufacturing process. 
In certain canned products, such as carbonated beverages, there is 
substantial internal pressure that can be in the order of 90 to 100 psi or 
even greater, and must be quickly and safely vented during the initial 
opening of the can end by the consumer. According, can ends are 
constructed for venting or releasing the internal pressure of the 
container during the initial operation of the easy open mechanism of the 
end. The mechanism of venting is described in prior art patents such as 
U.S. Pat. Nos. 4,015,744 and 4,030,631, the contents of which are 
incorporated by reference herein as if fully set forth. As briefly 
mentioned above, the easy open mechanism includes an end panel which is 
attached to the can body or container. A tear panel is defined in the end 
panel by a scoreline. An operating tab including a nose which extends 
partially over the tear panel is connected by a rivet to the end panel. 
The rivet defines a pivot point for tab operation. My co-pending patent 
application U.S. Ser. No. 08/476,406, filed Jun. 7, 1996, entitled, 
"Improved Easy Open Container End, Method of Manufacture, and Tooling" 
discloses new features that cooperates with the scoreline. 
Basically, initial lifting of the tab produces an upward force on the rivet 
and a downward force on the edge of the tear panel adjacent a beginning 
point of the tear panel scoreline. This in turn causes an initial opening 
of the tear panel beneath the nose of the tab in an area referred to as 
the vent region of the can end. Further lifting motion of the tab causes 
the tear panel to separate progressively along its scoreline, leaving a 
small integral connection or hinge between the end panel and the tear 
panel, about which the tear panel is rotated. The separation of the tear 
panel defines an opening through which container's contents can be poured. 
As mentioned above, there can be substantial internal gas pressure in the 
container. During the initial opening motion, this gas pressure must vent 
safely. It is the typical practice to define a small vent opening with a 
hook formation at the radially inward end of the scoreline. The vent 
opening or region extends to a score stop located in the region where the 
tear panel scoreline proceeds outward at the end. Typically, the score 
stop is in the form of a shallower segment of the scoreline of relatively 
short length as described in U.S. Pat. No. 4,503,989. The contents of this 
patent are incorporated herein by reference as if fully set forth. This 
score stop provides an increase in tear resistance along the scoreline. 
This opening process can be identified by the initial "pop" that is heard 
when the tab is lifted, followed by the "metal tearing" sound that 
accompanies the separation of the tear panel from the can end as the nose 
of the tab is "pushed" against the tear panel. 
The continuing evolution toward larger tear away panel opening areas 
relative to the overall surface area of the can end has created several 
challenges in the can making industry. This relative size of the tear away 
panel is at least in part the result of the continuous down-sizing of can 
end diameters. 
It is useful to understand what is meant by reference to a "large" opening 
end or to "larger" tear away panels. For example, a conventional 202 easy 
open end has a tear away panel that defines an area of approximately 0.450 
square inches. The same 202 easy open end that is equipped with a larger 
tear away panel has a panel that defines an area of approximately 0.596 
square inches. Accordingly, a large opening end may be characterized as 
being between about 20% and 40% larger than a conventional tear panel. 
Among the challenges associated with larger tear away panels are: the 
prevention of missiling or tear panel blow off, i.e., the catastrophic 
failure of the tear panel; the efficient mechanical operation of the 
larger tear panel with the use of the existing tab; the avoidance of the 
partial opening or incomplete opening of the tear panel; and maintaining 
"pop" and "push" values at a level that is satisfactory and convenient to 
the end user. Examples of large opening ends are available in my co 
pending patent applications, including application Ser. No. 29/048,638. 
The instant invention also addresses a technique for providing heightened 
control of the panel opening process through the use of a tab nose bead 
formed into the tear away panel. 
It is an object of this invention to provide a can end having a large 
opening tear panel that demonstrates improved and consistently-acceptable 
operational capabilities. 
It is yet another object of this invention to provide a can end tear away 
panel configuration suitable for use with both conventional and large 
opening ends. 
It is still another object of this invention to provide an improved set of 
tooling for the manufacture of converted can ends. 
It is another object of this invention to provide a converted can end and a 
method for manufacturing the same. 
SUMMARY OF THE INVENTION 
The invention provides an easy open can end with unique features formed 
into the tear away panel structure structure such that openability is 
enhanced for conventional and large opening ends. Additionally, the 
improved panel structure includes a tab nose bead disposed on the tear 
away panel. The invention further provides both a method for further 
forming a can end to incorporate the unique individual-structural features 
described above, and tooling for carrying out the process and apparatus of 
the invention. In an easy open can end for a beer or beverage container 
the can end has a tear panel defined by a fracture scoreline surrounding a 
portion of the periphery of said tear panel. The fracture scoreline 
defines a region where the tear panel is to be separated from the 
remainder of the end to define an opening through the end. The end 
includes an operating tab and an integral rivet attaching the tab to the 
end adjacent the fracture scoreline. The rivet is on the opposite side of 
the fracture scoreline from the tear panel. The fracture scoreline 
includes a vent region adjacent the rivet constructed and arranged to open 
initially at the vent region in response to the lifting of the rivet by 
the tab. During the lifting of the tab there is often an initial "pop" 
followed by some brief resistance. Once this resistance, typically an 
anti-missiling feature, is overcome, the tear panel tends to separate from 
the panel with a generally uniform pressure. This final opening effort is 
often referred to in the industry as the "push" that follows the initial 
"pop" that occurs when the consumer opens an easy open can end and vents 
its contents. 
According to my invention, the tear away panel is further formed to include 
a tab nose bead and a deformation in the tear away panel that defines a 
shallow panel. 
Tooling for the conversion of a can end shell into an easy open can end 
comprises several separate stations that are adapted for incorporation 
into a complete tooling set for a can end conversion press. According to 
this invention, preferably one of the tooling stations is adapted to 
further form the panel metal so as to provide the shallow panel and 
optionally, the nose bead.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
A conventional converted can end incorporating that is well known in the 
art is shown in FIGS. 1A and 1B, that are identified as being Prior Art. 
Can end 10 has an end panel 12 of generally circular shape which includes 
a circumferentially extending raised edge 14 for attaching the can end 10 
to a suitable cylindrical beverage can (not shown) or the like. In 
general, the can end 10 will be manufactured of a relatively ductile metal 
such as aluminum, but it may be made from other acceptable materials as 
required. 
A retained tear strip 16 extends across can end 10 from a position spaced 
inwardly of raised edge 14 to approximately the center of can end 10. Tear 
strip 16 is defined by a generally V-shaped score 18 with open end 20 of 
the V positioned toward the center of can end 10. A score 18 is 
interrupted so that tear strip 16 will be captively retained on the 
underside or product side, 22 of can end 10 when torn open. The tear 
strip, or retained panel, 16 is typically re-enforced by means of a bead 
19 that is formed into the panel 16. It is the conventional practice to 
form the bead 19 so that it follows the contour of the score 18. The bead 
19 may or may not continue under the nose of the pull tab 26. 
Nevertheless, the bead 19 typically is continuous and serves to stiffen 
the panel. 
An integral rivet 24 is positioned adjacent open end 20 of V-shaped score 
18, and a graspable ring-like pull tab 26 which may be of any desired size 
and configuration is secured to can end 10 by means of rivet 24. Pull tab 
26 is provided with a nose portion 28 to initiate the tear along score 18 
upon lifting of pull tab 26 whereupon tear strip 16 is torn open as is 
well known in the art. As can be seen, pull tab 26 is provided with a 
finger portion 30 opposite the nose portion 28. The open end 20 of the 
V-shaped score is below the nose 28 of the tab 26 and the adjacent the 
rivet 24. This portion of the can end 10 panel 12 is the vent region. It 
is during the initial lifting of the tab by the consumer, that this vent 
region is opened and internal pressure released or vented. It is to be 
appreciated that the industry is constantly striving to reduce the gauge 
of material from which can ends are manufactured. For example, most 
existing ends are dimensioned as 206, 204, or 202 diameter ends. A "206 
diameter" end means that the end is 26/16 inches in diameter and a "202 
diameter" end means that the end is 22/16 inches in diameter. As the can 
end has become smaller and smaller in diameter, so also has the gauge of 
the metal used to fabricate the end been reduced. The 206 diameter end was 
typically manufactured from metal having a thickness of between about 
0.0096 and 0.0106 inches, while a 202 diameter end is typically 
manufactured from metal having a thickness of about 0.0088 inch. As 
mentioned above, as the diameter of the end has decreased, the relative 
size of the tear away panel has increased, even before the dimensions of 
the panel opening were enlarged. 
The manufacture of a can end shell into an easy-open can end takes place in 
a conversion press, a portion of which is shown in FIG. 2. The Minster 
Machine Company of Minster, Ohio manufactures and sells an industrial 
press suitable for configuration as a can end conversion press. The 
conversion press 40 generally include a stationary press bed 42 including 
a generally planar horizontal upper surface 44. The upper surface supports 
a tooling base 46 which has a planar bottom surface 48 and a planar upper 
surface 50. Positioned upon the upper surface of tooling base is a lower 
tooling member 52 (shown in phantom) which make take a variety of shapes 
depending upon the tooling operation to be performed on the can end shell 
54. However, each lower tooling member 52 has a planar bottom surface 56 
which mates with the upper surface 50 of the tooling base 46 to provide 
secure support for the lower tooling member 52. 
A vertically displaceable press ram 58 overlies press bed and includes a 
generally planar horizontal lower surface 60. This surface 60 of the press 
ram 58 supports a tool support means 62 which may take a plurality of 
shapes depending upon the type selected for a particular tooling 
operation. In general, however, the tooling support means or base 62 
includes an upper planar surface 64 which provides solid mating contact 
with the surface 60 of the press ram 58 so that the tooling support means 
62 is securely fastened to the press ram. The tool support means 62 
securely supports an upper tooling member (shown in phantom) 66 having an 
upper planar surface 68 that is in mating contact with the lower planar 
surface 70 of the tool support means 62. The upper tooling member 66 can 
be one of many shapes and sizes depending upon the particular tooling 
operation to be performed. Typically, a centering ring 72 locates the can 
end shell 54 in each tooling station. The various types of tooling 
operations to be performed in succession include: bubble forming in the 
center of the open can lid, forming the bubble into a button; scoring an 
opening; paneling the can end in an area surrounding the scored opening; 
staking the pull tab to the can end; and stamping incise lettering upon 
the can end for messages such as "lift up, pull back" or "dispose of 
properly". U.S. Pat. No. 4,610,156, which is assigned to the assignee of 
the instant invention, sets forth a detailed description of the various 
tooling stations of a conversion press. The contents of this patent are 
incorporated herein by reference as if fully set forth. The can end 
conversion process may require from six to eight stations in which 
differently configured tooling carries out successive coldworking of the 
metal in the several steps in the conversion of a can end shell in an 
easy-open can end. 
As shown in FIGS. 1a and 1b, the conventional, prior art practice is to 
form a stiffening bead 19 located inside of the score lines. This bead is 
typically called the "D-bead" and serves to stiffen the tear away panel to 
facilitate the separation of the tear away portion of the panel from the 
can end. In operation, the tab is rotated upwardly causing the score vent 
region proximate the tab rivet to separate. The separation initiates at 
the vent region and follows along in a clockwise manner along the score 
line, with the separation terminating in the hinge portion. At the hinge 
portion, the tear away panel bends downwardly from the product side of the 
can end panel. While the use of the stiffening bead has proven to be a 
desirable feature of standard size tear away panel openings, I have found 
that a stiffening bead when used in a larger opening can end may result in 
the failure of the tear panel to completely separate. I believe that this 
difficulty is due to the fact that the bead 19 disposed inside of the 
score path causes the disk to form a convex shape. As a result, when the 
tab is rotated upwardly to initiate separation along the score line, the 
bead tends to urge the tear away panel or disk in a generally outward 
direction against the score. This causes a phenomena that is known in the 
can end industry as a "lock-out". It is believed that this takes place 
because the tear panel tends to wedge itself into the opening defined by 
the score line. 
Turning now to FIGS. 3 through 5, a can end incorporating the features of 
the instant invention is generally indicated by the reference character 
110. A main score 118 defines the outline of the tear panel 116. As is 
known in the art, the depth of the scoreline 118 may vary along the 
perimeter of the tear panel 116 and include anti-missile features as 
previously discussed. 
In order to resolve the problem described above, the instant invention 
further forms the tear panel 116 to include a shallow panel 182. This 
shallow panel is believed to allow the disk to stay flat or even to flex 
downwardly during the opening operation. As a result, as the tab is 
rotated upwardly to initiate venting and opening, the tear away panel 
flexes downwardly near its central region to effect the phenomenon wherein 
the tear away panel has a seemingly lesser diameter than the opening in 
which it had previously resided, thus facilitating the complete separation 
of the tear away panel from the can end. It is believed that the shallow 
panel configuration enhances the stiffness of the tear away panel 
proximate the rivet while at the same time facilitating the flexibility of 
the panel in the area of the panel distal the rivet. Thus the combination 
of relative stiffness on the one hand, and flexibility on the other, 
enhances the operation and thus the functionality of this member. It is 
also believed that the use of the shallow panel of this invention will 
permit the manufacture of a can end in which a higher score residual is 
maintained. To the consumer, the functionality of the easy-opening end is 
improved and access to the container's contents made easier and more 
reliable. I have also discovered that the use of a tab nose bead as at 150 
may also serve to enhance even further the functionality of the end. It is 
to be understood that while the shallow panel and nose bead can both be 
incorporated into a can end, either feature may be used individually. In 
my preferred embodiment, the shallow panel is used alone. 
The shallow panel 180 is formed in the panel 116 of the can end 112. The 
shallow panel is disposed downwardly with respect to the plain 156 defined 
by the tear panel. The shallow panel includes a forward portion 184 and a 
rearward portion 186 that is closest to the rivet 124 of the can end. 
Additionally, side portions 188 and 190 define the outward boundaries of 
the shallow panel. Preferably, the shallow panel slopes downwardly and 
rearwardly from a point as at 184 distal the rivet to 186 proximate the 
rivet. The rearward portion 186 of the shallow panel 180 is proximate and 
follows the profile of the tab nose 128. In other words, the rearward 
portion of the shallow panel may be curvilinear as shown to provide 
clearance for the location of the nose bead and surface area of the tear 
away panel with which the tab engages during opening. However, the nose 
128 does not extend over the rear portion 128 of the shallow panel 180. 
The tear away panel 116 has a product surface 158 and a public surface 
160. The shallow panel gradually slopes downwardly from a point at 184 
defining the forward portion of the shallow panel increasing the relative 
distance of the bottom of the shallow panel's rearward portion 186 to a 
maximum depth with respect to the plane 156 at a point proximate the nose 
128 of the tab 126. In practice, I have found it appropriate to form the 
shallow panel into the can end prior to the indexing of a can end into a 
tear away panel scoring station. 
As best shown in FIGS. 3 and 4, a rivet 124 secures the tab 126 to the can 
end 112. A tab nose bead 150 is disposed beneath the nose portion 128 of 
the tab 126. The tab nose bead 150 is positioned between the rivet 124 and 
the shallow panel 180. The nose bead 150 consists of an elevated portion 
152 and descending side walls 154. 
The elevated portion 152 is higher than a first elevation defined by the 
bottom of the panel 112. 
The metal from which the can end is formed has a thickness of about 0.085 
to 0.088 inches. However, it is to be appreciated that the industry is 
constantly striving to reduce the thickness or gauge of the metal from 
which packaging is produced in order to enhance the savings achievable 
from the use of recyclable aluminum. Preferably, the tab nose bead is 
elevated above the plane defined by the tear away panel by approximately 
0.010 inches to about 0.019 inches. It is preferred that the nose bead 
elevation be within the range of approximately 0.010 to 0.015 in order to 
minimize potential adverse effects on the stacking of the converted can 
ends. When seen in plan view, the tab nose bead 150 has a width of 
approximately 0.090 inches, plus or minus 0.005 inches and a longitudinal 
length with respect to the longitudinal axis of the tab 126 of about 0.125 
inches plus or minus 0.005 inches. The tab nose bead provides a mechanism 
whereby the tab 126 can exert better push force upon the tear away panel 
116 during the rotation of the tab about the rivet. 
The tooling by which both the tab nose bead and the shallow panel can be 
formed into a can end is shown in sectional views in FIGS. 5A and 5B. The 
tooling 210 consists of a lower tooling member 212 and an upper tooling 
member 214. The upper tooling member 214 includes a relief portion 216 
that corresponds with an anvil-like portion 218 disposed in the lower 
tooling member 212. The anvil 218 is preferably formed from a removable 
insert that allows for both replacement due to wear or adjustment through 
selective elevation thereof as is well known in the art. 
Preferably, during operation, the tab nose bead is formed so as to have 
gently sloping side walls 154 extending from the elevated portion 152 to 
the panel. Appropriate clearance is provided between the top and sides of 
the anvil 218 and the relief portion 216 of tooling member 214. 
The tooling by which the shallow panel is formed includes a lower portion 
212 and an upper portion 214. The lower portion 212 includes a relief 
portion 236 into which the upper forming tooling portion 234 further forms 
the can panel when the tooling is moved from a spaced-apart position to a 
closed metal forming position. As can be seen, the longitudinal axis of 
the upper tooling member shows that the upper tooling member has an 
increasing depth from the forward portion of the shallow panel to the 
rearward portion proximate the rivet of the can end. 
The instant invention is directed particularly to an improved method of can 
end formation, the tooling for this formation, and an easy-open can with 
improved openability resulting from the use of either a shallow panel, a 
tab nose bead disposed in the panel, or both. It is to be appreciated that 
while the improvements disclosed herein have been shown with a large 
opening end, either or both of these features are suitable for use with 
can ends incorporating a more traditionally sized tear away opening. While 
the method herein described, and the forms of apparatus for carrying this 
method into effect, constitute preferred embodiments of this invention, it 
is to be understood that the invention is not limited to this precise 
method and forms of apparatus, and that changes may be made in either 
without departing from the scope of the invention which is defined in the 
appended claims.