Note: Descriptions are shown in the official language in which they were submitted.
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DOUBLE SEAMING CHUCK-KNOCKOUT
TECHNICAL FIELD
[0001] The present technology relates to manufacturing of metal packaging.
More
particularly, the invention relates to an apparatus and methods for assembling
a container and
can end.
BACKGROUND
[0002] In the field of metal packaging, typical containers are sealed by
seaming a can end
onto a can body using the well-known double seaming process. The double
seaming process is
typically performed on a seaming machine having a plurality of forming
stations. Each station
contains a rotatable seaming chuck that acts as an anvil to support the can
end while two
rotatable seaming rolls are brought into contact with the container using a
cam motion. The two
seaming rolls define specific groove geometries that are configured to form a
portion of the can
body and a portion of the can end into a commercially acceptable double seam.
[0003] A can body is typically raised into engagement with a forming station
using a
lifter plate or other positioning mechanism. After the double seam is formed
and the positioning
mechanism is retracted, the sealed container is ejected from the station so
the seam-forming
cycle can be repeated on another container. Typically, ejection of the seamed
container may be
achieved by the use of a knockout rod or pad that taps the center of the
container to knock the
container out of engagement the seaming chuck.
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[0004] A trend in beverage cans has been toward reduced end diameters.
Further, many
conventional beverage can ends have a small center panel diameter relative to
a seaming panel or
peripheral curl diameter. For example, United States Patent Numbers 6,065,634,
6,702,142,
6,516,968 and 7,350,392, each of which is incorporated by reference in its
entirety, disclose
beverage can ends having a relatively small center panel because the chuck
wall is inclined (as
measured from an upper point to a lower point of the chuck wall).
[0005] The conventional design of knockout pad and seaming chuck is such that
the
seaming chuck locates the can end. Thus, conventional knockout pads typically
fit inside the
diameter of the surface of the chuck that contacts the can end, which leaves a
certain amount of
radial movement between the can end and the knockout prior to engagement with
the seaming
chuck. With certain end designs (i.e. lightweight ends) the countersink is
moved inboard and
with the traditional design of knockout, the radial movement available to the
can end prior to
engagement with the seaming chuck is increased. This radial movement is a
result of the
knockout not having a feature that locates and controls the end concentric
with the rotatable
seaming chuck. With this radial movement comes the opportunity for
misalignment on assembly
with the seaming chuck (during what's called the transition zone) which may
cause collapse,
creases and poor seam quality.
[0006] Furthermore, after conventional knockouts have located a can end, the
load
applied to the can end decreases to zero during the transition zone.
Therefore, by the time the
can body and can end engage the chuck, the can end and can body combination
could be
misaligned to the chuck, thereby causing damage to the can bodies and can
ends. To prevent
damage, often times certain seamers have to run at slower speeds such as less
than 1500
cans/minute.
[0007] Accordingly, there is a need for an improved apparatus and method for
locating
and seaming a can end onto a can body.
SUMMARY
[0008] A chuck-knockout assembly that (among other things) gives improved
location of
a can end during the seaming operation (i.e. at least during the transition
zone). Such
improvements may be achieved by utilizing some or all of the features of the
chuck-knockout
assemblies described below.
[0009] In one embodiment, a chuck-knockout assembly for seaming a can end onto
a can
body to form a seamed container may include an upper chuck body and a lower
chuck body.
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The upper chuck body may include a first drive surface. The first drive
surface may at least
partially define a seaming surface for contacting a portion of the can end
during seaming and
against which a seaming force is applied. The lower chuck body is
longitudinally moveable
relative to the upper chuck body and includes a second drive surface. The
second drive surface
may be located outboard of a periphery of a center panel of the can end. The
second drive
surface may be capable of locating the can end prior to seaming, may be
capable of maintaining
the can end during seaming and may also be capable of contacting the can end
to disengage the
can end from the chuck-knockout assembly after seaming.
[0010] The second drive surface of the lower chuck body may be configured to
engage a
countersink of the can end. Furthermore, the can end may comprise a pull tab,
and the lower
chuck body may be configured to be devoid of contact with the pull tab during
the seaming and
release.
[0011] A seaming system for seaming and release of a container including a can
end and
a can body is also provided. The seaming system may comprise a chuck-knockout
assembly and
first and second seaming rolls. The chuck-knockout assembly may include an
upper chuck body
and a lower chuck body. The upper chuck body may include a first drive
surface, and may be
rotatably coupled to a seaming machine frame. The lower chuck body may include
a second
drive surface, and may be longitudinally moveable relative to the upper chuck
body. The first
and second seaming rolls may be configured to form a seam on the container
between the can
end and the can body. The first drive surface and the second drive surface may
define a seaming
surface when the seam is being formed. The second drive surface may contact an
outer
periphery of the can end during release of the container from the chuck-
knockout assembly.
[0012] A method of seaming a container including a can end and a can body is
also
disclosed. The method may comprise the steps of (1) providing a chuck-knockout
assembly
comprising an upper chuck body and a lower chuck body; (2) locating a can end
from an infeed
mechanism onto the chuck-knockout assembly such that a second drive surface of
the lower
chuck body is in contact with a periphery of the can end; (3) seaming the can
end to a can body
to form a container while the second drive surface is in contact with the
periphery of the can end;
and (4) releasing the container from the chuck-knockout assembly by moving the
lower chuck
body longitudinally relative to the upper chuck body, the lower chuck body
moving from a
seaming position to a knockout position, wherein the second drive surface is
in contact with the
periphery of the can end as the lower chuck body is moving to the knockout
position.
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[0013] In another embodiment a chuck-knockout assembly may utilize a vacuum
force to
locate the can end. For example, a chuck-knockout assembly may include a chuck
body having
an aperture and a first drive surface that at least partially defines a
seaming surface for contacting
a portion of the can end during seaming and against which a seaming force may
be applied. A
vacuum force may be applied through the aperture to locate the can end onto
the chuck body
prior to seaming and may hold the can end during seaming.
[0014] By using chuck-knockout assemblies that provide improved location of
can ends
certain seamers may be operated at higher speeds. The improved location may
among other
things be as a result of sufficient loads being applied to the can end and can
body combinations
during at least a majority of the transition zone. Therefore a method of
seaming a can end onto a
can body to form a container, may include (1) positioning the can end on top
of the can body; (2)
lifting the can body and can end combination with a lifter plate; (3) locating
the can end with a
chuck-knockout assembly such that the can body and can end combination is
between the lifter
plate and the chuck-knockout assembly; (4) maintaining a load that is between
15 and 100 lbf on
the can body and can end combination for at least part of the transition zone;
and (5) seaming the
can end onto the can body during a first seaming operation. Preferably the
load in the transition
zone is maintained between about 30 lbf and about 38 lbf and even more
preferably at about 35
lbf.
[0015] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a side cross-sectional view of a seaming system seaming a can
end onto
a can body;
[0017] FIG. 2 is a schematic showing a seaming operation;
[0018] FIG. 3A is a side cross-sectional view of a chuck-knockout assembly
capable of
being used in the system depicted in FIG. 1;
[0019] FIG. 3B is a side cross-sectional view of the chuck-knockout assembly
depicted
in FIG. 3A in a knockout position;
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[0020] FIG. 4A is a partial side cross-sectional view of a seaming system with
the chuck-
knockout assembly in the seaming position as depicted in FIG. 3A;
[0021] FIG. 4B is a partial side cross-sectional view of a seaming system with
the chuck-
knockout assembly in the knockout position as depicted in FIG. 3B;
[0022] FIG. 5 is a side view of a cam for actuating a knockout;
[0023] FIG. 6 is a graph showing the loads applied to a can end during at
least a
transition stage of the seaming operation; and
[0024] FIG. 7 is a side cross-sectional view of another chuck-knockout
assembly capable
of being used in the system depicted in FIG. 1.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0025] Preferred structures and methods for container seaming technology are
described
herein. An embodiment of a seaming system and chuck-knockout assembly that
employ this
technology are also described. The present invention is not limited to any
particular seaming
configuration but rather encompasses use in any container seaming application.
Further, the
present invention encompasses other seaming system and container designs not
described herein.
[0026] Referring to FIG. 1, a seaming system 10 includes a seaming machine
frame 11, a
chuck-knockout assembly 12 (including a knockout and a chuck), a first seaming
roll 14, and a
second seaming roll 15. Seaming machine frame 11 includes a shaft 13 for
rotating chuck-
knockout assembly 12 and a lifter plate 16 for lifting a container 20
containing a product 23 into
engagement with chuck-knockout assembly 12. Chuck-knockout assembly 12 is
affixed to shaft
13 and rotatably coupled to seaming machine frame 11. First seaming roll 14
and second
seaming roll 15 are configured to form a double seam 24 in container 20 that
seals a can end 26
onto a can body 28 via a seaming process that is known in the art (e.g.,
bending a curl portion of
can end 26 around the top edge of can body 28).
[0027] FIG. 2 is a schematic showing the seaming operation. First, a can body
and can
end enter the seamer at point A. At point B which may be approximately 1
degree from point A,
the can body picks up the can end. At this point, the knockout makes contact
with and locates
the can end and can body combination. From point B to point C is known as the
transition zone.
The can end engages the chuck at point C which is about 24.5 degrees from
point A. At point D,
which is about 27 degrees from point A the first seaming operation begins and
at point E, which
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is about 148 degrees from point A the second seaming operation begins. The can
body and can
end combination is then discharged at point F which is about 218 degrees from
point A.
[0028] During the seaming operations, chuck-knockout assembly 12 may be
rotated by
shaft 13 or a seaming head or spindle (not shown) attached to shaft 13 about
an axis indicated by
arrow Y in FIG. 1. First seaming roll 14 and second seaming roll 15 may be
brought into contact
with container 20 (typically using a cam motion), and first seaming roll 14
and second seaming
roll 15 may be rotated about an axis also indicated by arrow Y. Chuck-knockout
assembly 12
may support one or more surfaces of can end 26 while first seaming roll 14 and
second seaming
roll 15 apply a force (generally directed radially inward) to container 20 to
form double seam 24.
[0029] After seaming, lifter plate 16 may be lowered, and a portion of chuck-
knockout
assembly 12 may push against can end 26 to eject or release container 20 from
chuck-knockout
assembly 12. The seaming cycle may then be repeated to form double seam 24 on
another
container 20.
[0030] Seaming system 10 may typically form a double seam 24 on a variety of
types of
containers 20. A typical container 20 may contain or be configured to contain
product 23,
including a beverage, ready meals, fruits, vegetables, fish, dairy, pet food,
or any other product
that it is desirable to store in metal packaging such as container 20.
Container 20 may have any
length, diameter, wall thickness, and volume. Container 20 typically has a
standard-sized
interior volume that is known in the art for containing product 23 such as a
beverage, ready
meals, fruits, vegetables, fish, dairy, or pet food.
[0031] Container 20, including can end 26 and a can body 28 may be made from
any
material, for example, steel, aluminum, or tin plate. Can end 26 may include
an approximately
planar panel that maybe formed, pressed, and/or stamped to take a shape that
may include
several features. Can end 26 may include an openable panel portion (not shown)
that extends
over a portion or most of can end 26, and the openable panel may be opened by
breaking a score
(not shown) to create an aperture (not shown) through which a user may remove
product 23.
Can end 26 may include a pull tab (not shown) to allow a user to open the
openable panel portion
to remove product 23.
[0032] Referring now to FIGs. 3A and 3B, a chuck-knockout assembly 12a may be
used
in a seaming system such as seaming system 10 (shown in FIG. 1). As shown,
chuck-knockout
assembly 12a includes an upper chuck body 30 and a lower chuck body 34. Upper
chuck body
30 and lower chuck body 34 together at least partially define a seaming
surface 38 during
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seaming of an end onto a container. Lower chuck body 34 also helps locate and
maintain the can
end prior to seaming of the can end onto the can body (i.e. during the
transition zone shown in
FIG. 2) and may eject or release the can end from the chuck-knockout assembly
12a after
seaming. Chuck-knockout assembly 12a defines a longitudinal axis Y.
[0033] As shown in FIGs. 3A and 3B, upper chuck body 30 includes a first drive
surface
42 that partially defines seaming surface 38. As shown, first drive surface 42
is approximately
vertical. Upper chuck body 30 also defines one or more retainer cavities 46
that may be coupled
to one or more retainers or protrusions (not shown) extending from shaft 13 or
a seaming head or
spindle (not shown) to affix chuck-knockout assembly 12a to shaft 13. In other
embodiments,
any other retention mechanism that is known in the art may be used to affix
chuck-knockout
assembly 12a to shaft 13. Upper chuck body 30 mates with lower chuck body 34
along an outer
mating surface 50 and an inner mating surface 54.
[0034] Upper chuck body 30 may be made from any material, for example, steel
or iron.
Upper chuck body 30 preferably has a generally cylindrical outer shape,
centered around
longitudinal axis Y. Upper chuck body 30 may include an internal void (not
shown) that may be
configured to allow a portion of a knockout rod assembly 58 to pass through
upper chuck body
30 and be affixed to lower chuck body 34.
[0035] Lower chuck body 34 includes a second drive surface 62 that may serve
multiple
purposes. For example, second drive surface 62 partially defines seaming
surface 38 during the
seaming operation. Second drive surface 62 may also locate the can end prior
to the seaming
operation and may serve to push against the can end to disengage or release a
sealed container
from chuck-knockout assembly 12a after seaming. Second drive surface 62
preferably has a
cylindrical or frusto-conical shape that may be configured to mate with
corresponding peripheral
features of the can end (as shown, for example, in FIGs. 4A and 4B). As shown,
a portion of
second drive surface 62 may extend into a countersink of the can end. Lower
chuck body 34
also defines a central cavity 66 that may allow one or more radially inward
features of the can
end (e.g., a lift tab, a score, or an openable panel portion) to be devoid of
contact with chuck-
knockout assembly 12a during and after seaming). In this regard, the upper
surface that forms
cavity 66 preferably is spaced apart from the can end.
[0036] Lower chuck body 34 may be made from any material, for example, steel
or iron,
and may be coated or surface treated. Lower chuck body 34 preferably has a
generally
cylindrical outer shape, centered around longitudinal axis Y. Lower chuck body
34 may be
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coupled to knockout rod assembly 58 (preferably cam-actuated) which may pass
through
apertures in upper chuck body 30 and shaft 13 and may be coupled to seaming
machine frame 11
(shown in FIG. 1).
[0037] As shown in FIGs. 3A and 3B, lower chuck body 34 maybe slideable along
longitudinal axis Y relative to upper chuck body 30 between a seaming position
and a knockout
position. Lower chuck body 34 may be substantially angularly fixed relative to
upper chuck
body 30 in both the seaming position and the knockout position. Lower chuck
body 34 may
have a substantially constant angular position about longitudinal axis Y
relative to upper chuck
body 30, such that upper chuck body 30 and lower chuck body 34 may rotate
together about
longitudinal axis Y (e.g., during seaming). To permit lower chuck body 34 to
be slideable
relative to upper chuck body 30 only along longitudinal axis Y, mating
vertical corrugations or
splines (not shown) may be provided in the outer surface of lower chuck body
34 and the inner
surface of upper chuck body 30. Lower chuck body 34 may be actuated along
longitudinal axis
Y by the motion of knockout rod assembly 58, which preferably is cam-actuated.
[0038] When lower chuck body 34 is in the seaming position, as shown in FIG.
3A, an
outer mating surface 70 of lower chuck body 34 may be in contact with or
disposed proximate to
corresponding outer mating surface 50 of upper chuck body 30, and an inner
mating surface 74
of lower chuck body 34 may be in contact with or disposed proximate to
corresponding inner
mating surface 54 of upper chuck body 30.
[0039] When lower chuck body 34 is in the knockout position, as shown in FIG.
3B,
outer mating surface 70 of lower chuck body 34 may be spaced apart from outer
mating surface
50 of upper chuck body 30, creating an outer separation gap A, and inner
mating surface 74 of
lower chuck body 34 may be spaced apart from inner mating surface 54 of upper
chuck body 30,
creating an inner separation gap B. The distance that surfaces 50 and 70 and
that surfaces 54 and
74 are spaced apart may be chosen by person familiar with seaming technology
according to
well-known principles upon consideration of this disclosure.
[0040] Referring now to FIGs. 4A and 4B, chuck-knockout assembly 12a may be
configured to engage and support corresponding features on a can end 78 during
the seaming
operation. For example, while in the knockout position lower chuck body 34
locates can end 78
by having second drive surface 62 engage the outer periphery (i.e., at least
one of a chuck wall
86, a countersink 90, or a peripheral portion of an approximately planar
center panel of can end
78 located near countersink 90 but radially outside of a pull tab or tear
panel) of can end 78.
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Lower chuck body 34 then moves to a seaming position so that the end 78 may be
seamed onto a
can body 82. As shown in FIG. 4A first drive surface 42 and second drive
surface 62 together
define seaming surface 38 when lower chuck body 34 is in the seaming position.
During
seaming, seaming surface 38 serves as an anvil to support a portion of chuck
wall 86 of can end
78 against the generally inwardly-directed force applied by a first seaming
roll (not shown) and a
second seaming roll 92 to form a double seam 94.
[0041] As a result of the seaming process, chuck wall 86 may exert a retention
force
(generally directed radially inward) on seaming surface 38. Also, a portion of
chuck wall 86
may be partially bent around the upper corner of seaming surface 3 8 (I. e.,
can end cut-over),
thereby increasing any retention force that chuck wall 86 may be exerting on
seaming surface 38.
[0042] After seaming, as shown in FIG. 4A, and subsequent lowering of the
lifter plate
(i.e. lifter plate 16 shown in FIG. 1), lower chuck body 34 moves from its
retracted position of
FIG. 4A to the extended or knockout position as shown in FIG. 4B. As lower
chuck body 34
moves to the knockout position the container may be ejected from chuck-
knockout assembly
12a. To eject the container, lower chuck body 34 may be moved downward
relative to upper
chuck body 30, along longitudinal axis Y. Lower chuck body 34 may be moved
downward by
knockout rod assembly 58, which may slide through a void inside upper chuck
body 30.
[0043] As lower chuck body 34 begins to move down, lower chuck body 34 may
exert an
ejection force on the container via second drive surface 62. Second drive
surface 62 preferably
pushes downward on a periphery of can end 78. The presence of cavity 66 may
allow second
drive surface 62 to push down on the periphery of can end 78 while being
devoid of contact with
one or more radially inward features of can end 78 (e.g., a lift tab, a score,
or an operable panel
portion). The openable panel portion, score, and/or pull tab may penetrate
into cavity 66 without
contacting lower chuck body 34.
[0044] As lower chuck body 34 continues to move down, the separation of outer
mating
surfaces 50 and 70 may begin to create outer separation gap A, and the
separation of inner
mating surfaces 54 and 74 may begin to create inner separation gap B. Lower
chuck body 34
continues to move down until separation gap A is large enough that the
retention force that a
portion of chuck wall 86 exerts on seaming surface 38 becomes less than the
gravitational force
acting to pull the container off of chuck-knockout assembly 12a, at which
point container 20
disengages from knockout assembly 12a. In some embodiments, lower chuck body
34 may
continue to move down until separation gap A is greater than the height of
double seam 94,
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thereby eliminating contact between chuck wall 86 and seaming surface 38 and
enhancing
disengagement or release of the container from chuck-knockout assembly 12a.
[0045] While not being bound by theory, it is believed that the improved
aligning of
second drive surface 62 with a periphery of can end 78, compared with using a
conventional
knockout rod, pin, or pad, may allow for a more controlled can handling, which
may reduce
seaming process time and reduce potential damage to seamed containers. For
example, having
an increased controllability of the can end while the can end is being located
and increased
stability of the container during ejection from chuck-knockout assembly 12a
may help prevent
the container from crushing or creasing during and after the seaming
operation.
[0046) In this regard, after a container 20 is ejected from chuck-knockout
assembly 12a,
lower chuck body 34 preferably contacts and locates another, incoming can end
while lower
chuck body 34 is in the extended, knockout position. Lower chuck body 34 then
moves upwards
relative to upper chuck body 30 along longitudinal axis Y, reestablishing
contact between outer
mating surfaces 50 and 70 and inner mating surfaces 54 and 74 and eliminating
the separation
gaps A and B. When chuck-knockout assembly 12a has returned to the seaming
position, the
double seaming process may be repeated, whereby a double seam may be created
on a new
container.
[0047] Lower chuck body may be actuated using a cam. As the lower chuck body
is
actuated in a downward direction, and once the lower chuck body has located a
can end, a
vertical load maybe applied to the can end to thereby hold the can end onto
the can body.
Preferably the load remains sufficient at least during the transition zone, as
explained more fully
below. FIG. 5 shows an example cam that may be used to actuate the lower chuck
body. As
shown, a cam 120 includes a path 124. As the chuck-knockout completes an
operation, the cam
profile will cause the lower chuck body to actuate.
[0048] By using a chuck-knockout assembly having some or all of the features
described,
a sufficient compressive load may be applied to the can end and can body
combination during at
least a majority of the transition zone of the seaming operation. Preferably
the compressive load
is applied during the entire transition zone. FIG. 6 is a graph that shows the
loads applied to the
can end and can body combination for three different knockout and lifter plate
combinations. As
shown, for combinations A and B which use a standard rise knockout and soft
rise knockout
respectively, a sufficient clamping load is applied for a portion of the
transition period and then
at about an angle of 6 or 9 degrees the clamping load decreases substantially.
However, for
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combination C which includes a chuck-knockout assembly utilizing at least some
of the features
described herein, an adequate clamping load is applied for at least 70 % of
the transition zone,
preferably at least 85 % of the transition zone, and even more preferably at
least 100 % of the
transition zone. As shown, the clamping load for combination C is sufficient
for the entire
transition zone. Preferably, for the commercial 12 ounce aluminum beverage
cans, the load is
between 15 and 100 lbf, more preferably the load is between 30 and 38 lbf, and
even more
preferably the about 35 lbf. By applying a load that is sufficient to the can
end and can body
combination, certain reamers may be operated at higher speeds with less damage
occurring to the
can end and/or can body. Sufficient load for other applications may be chosen
according to the
present disclosure based on parameters particular to the application.
[0049] Other embodiments of a chuck-knockout assembly that can improve the
locating
of the can end are envisioned. For example, the improved location may be
achieved by locating
off of another feature of the end such as off of the rivet or some other
feature of the can end.
[0050] Furthermore, the chuck-knockout assembly may include structures to help
reduce
or help create vacuum forces. For example a chuck-knockout assembly that
utilizes such a
feature is shown in FIG. 7. As shown, a chuck-knockout assembly l 2b includes
a chuck body
200 having an aperture 208 formed in the lower body of the chuck-knockout
assembly. A
vacuum manifold may be in communication with aperture 208 such that the vacuum
may be
controlled. The vacuum may be employed and the can end maybe located via the
vacuum
through aperture 208. It should be understood that the vacuum force may also
be used with
chuck-knockout assembly 12a. Alternatively vent hole 208 may be adapted to
release trapped
air when the chuck-knockout assembly 12b contacts the can end. By allowing air
to escape
vacuum created by the trapped air will be diminished to thereby make it easier
to release the can
after the seaming operation is complete.
[0051] The figures illustrate assemblies 12a and 12b employed with an end
shown in
United States Patent Number 6,065,634. The present invention is not limited to
use with this
particular can end. For example, the present invention encompasses employing
the apparatus
and methods described herein with the ends shown in United States Patent
Numbers 6,702,142,
6,516,968 and 7,350,392 or their commercial embodiments. The disclosures of
each of these
patents are incorporated herein in their entireties. Moreover, the present
invention is not limited
to use with beverage containers. The particular configuration of the chuck-
knockout assembly
for these and other ends will be clear to persons familiar with these other
can end configurations.
For example, the second drive surface may include a curved portion that drives
in or proximate
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to a knee or junction between can end chuck wall portions in circumstances in
which the end
chuck wall is a multiple-part chuck wall.
[00521 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. Those skilled in the relevant art,
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.
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