Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02581467 2007-03-23
11478p - for CA
Ball Europe GmbH
SHEET METAL COVER FOR A BEVERAGE
CAN, PROVIDED WITH A LARGE
PERFORATION
The invention relates to a lid made from sheet metal for closing container
bodies, the
content of which is under increased internal pressure, as is known from cans
for drinks
containing carbonic acid.
In order to be able to easily open such containers, it is conventional to
provide a defined
region in the lid panel (panel) of the sheet metal lid, which may be broken
and hence
exposed to the removal opening by external pressure. Various designs of the
break-
open region and various ways of applying the opening pressure are thus known,
inter
alia from US-A-3,361,261 (Fraze) having a trapezium-shaped rip-open region
within a
substantially oval area limited by folded lines (there 16, 18) at the edges.
This rolled-in
folded line stabilizes the panel. The oval area within the folded lines is
significantly
smaller than 30% of the overall panel.
Also in other lids, a limited region is originally closed by sheet metal and
is then
separated off by the action of a lever flap (tab) at a weakened line and
pressed into the
closed container. If one would like to design the can, and thus expressly the
lid, to be
reclosable, both solutions mentioned are not applicable.
Many other solutions in the state of the art are concerned with the
recloseability of
drinks cans, in particular under external (political) pressure and under
internal excess
pressure of the closed container. The pressure stress from both sides requires
from the
solution of a sheet metal lid a number of properties which cannot be easily
harmonised
and cannot be made available on a small surface. Many solutions of the state
of the art
which suggest recloseability, achieve this only by losing the stackability of
a can.
However, the stackability is an original property of a closed can which cannot
be lost. A
can must remain stackable over many layers without additional elements having
to be
added. The can may experience as few as possible modifying interventions
during
closing, in particular in the region of the sheet metal lid, in order to make
it easier for the
filler to get involved with a kind or a new type of can lid. Basically, the
principle of
recloseability must thus be different without a tab (mostly SOT) being
arranged on the
lid panel. Thus additional free space is available which was hitherto occupied
by the tab.
This additional space is situated directly in the lid plane (slightly
thereabove).
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It is the object of the invention to prepare a sheet metal lid for closing a
drinks can to
facilitate assembly of an initially separate reclosing device and to
facilitate its assembly
on the sheet metal lid. The sheet metal lid should also be designed so that it
retains its
pressure stability, that it does not lose the stackability and lies as close
as possible to a
standard shell in its at least external edge design in order to keep changes
on a filling
line as low as possible. The recloseability of the container should however be
facilitated
by the lid, since the ironed (by DWI) one-part can body cannot contribute
anything to
this solution (recloseability) due to its original properties.
The invention adds to a solution in which an additional part (a reclosing
device) is
inserted in a "large opening" in the lid panel. This additional part is not to
be an object of
this description and be claimed, but only the sheet metal lid which as such
brings with it
the suitability, property and precondition of being combined with such a
reclosing device
in order to then be mounted and rebated on a filled body as a closure lid by
the filler.
The large-dimension opening in the panel (the lid surface) should be
understood so that
it provides a significantly larger opening than is the case for the regions
which can be
broken described in the introduction. They have only relatively small
dimensions in
order to be able on the whole to keep the stability of the panel.
Indeed LOE closure lids are known (Large opening end), which provide an
enlarged
opening particularly for Gulp-drinks, which is orientated transversely and
designed to be
reniform, nevertheless not circular due to the necessity which continues to
exist of
attaching a tab to the lid sheet metal externally (via a rivet), and also this
reniform shape
lies only on one side of the axial centre plane of the lid, see WO 97/30902
(ANCC),
there Figure 9.
Using the invention, the opening surface area becomes large. A perforation is
preferably
introduced into the lid, the opening dimension of which goes beyond the lid
centre. The
large-dimension perforation is not closed by a sheet metal section and also
cannot be
broken open via a scored or weakened line, but remains open in order to be
closed later
by the reclosing device which has adapted geometry. It permits the opening and
closing
of the flow path in the opened region (the perforation) so that here a "large-
dimension
opening" will be discussed further on, which is free for the flow of the
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drink, controlled by the reclosing device, but which is not to be illustrated
here, see for
this in detail PCT/NL2004/00024, filed on 13th January 2004 (WO-A
2005/068312).
The sheet metal lid as such is now as before a finally shaped sheet metal lid
originating
from a manufacturing method. It is more than a shell (the crude form), it is
ready to be
combined with the reclosure in order then in this combination to replace a
conventional
SOT closure lid which is normal today by a scored line and to close in
reclosable
manner the bodies closed by it, which are likewise not illustrated here,
because they are
available according to standard.
An enclosing strip, which is offset in one plane, is provided around the large-
dimension
opening. It serves for stabilisation. A stiffening plateau placed radially
further outwards,
which contributes additionally to the stiffening of the sheet metal lid, is
provided along at
least one peripheral section of this enclosing strip. Due to the large
dimension opening,
a considerably loss of strength can be expected in the panel, which is
compensated by
the enclosing strip and the stiffening surface (stiffening plateau) extending
partly
peripherally around the enclosing strip. This is obtained by a staggered group
(sequence) of geometric shapes extending clearly in peripheral direction.
The stiffening plateau preferably extends not further than partly peripherally
and in
radial direction, wherein it is orientated to be flat, designed in particular
to be part moon-
shaped or arc segment-shaped. It may also be described so that it has a bulge
section
with greater radial dimension and two arm sections which extend peripherally.
The
plateau thus extends in a peripheral angle of more than 180 .
Due to a preferably centrally offset arrangement of the large opening, there
is more
remaining lid panel on one side of the opening than on the other side, where
the
opening extends closer to the peripheral groove. The central offsetting may be
in the
range between 5% and 25% of the diameter of the lid panel (in each case in the
non-
perforated state) depending on the dimensions of the main opening designed to
be
large and intended in most cases to be circular. A range between 10% and 15%
is
preferred, relative to the said diameter of the panel (lid panel) within the
peripheral
groove.
This offsetting towards one side (as seen from the centre) makes it possible
to attach
the additional stiffening on the other side due to the stiffening plateau in
part moon-
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shaped or arc segment-shaped design (in short 'half-moon-Nike'). It includes
at least 900,
preferably approximately 1800 of the opening and - relative to the lid panel -
is
designed to be encompassing more than 180 . Due to the central offsetting,
space is
provided between the one edge of the opening and the peripheral groove to
arrange this
stiffening.
On the other side remains less sheet metal area than the opening area defined
by the
perforation.
To outline a large opening, it is possible to start from more than 30% of the
surface of
the as yet non-perforated lid panel. This dimension relates to the surface
area which is
the square of the radius. If the size of the opening is related to diameter,
the diameter of
the opening (for substantially circular design) is greater than 50% of the
diameter of the
panel, the same also applies to the dimensions of the radii. A range between
55% and
65% is preferred. The opening is at least essentially round or at least
approximately
oval. It has a free inner edge.
Further details regarding the flat extension - seen in radial direction of the
lid panel - lie
in the peripheral strip which surrounds the large-dimension opening and leaves
between
the edge of the opening and the start of the peripheral strip, a further edge
strip which
also surrounds the opening. This edge strip and the previously mentioned
peripheral
strip lie in axial direction (vertically to the radial extension) on two
different levels, also
called height or height level or height position. The axial direction defines
the direction
vertically to the radials in cylindrical coordinates.
Speaking of "inner" and "outer" is avoided for a lid panel, since it is to be
described and
to be claimed in the state not arranged on the body.
When looking at the figures, it may be assumed that "outer" appears as "top"
in the
figures, but which is not a restriction with regard to the description of the
axial height
relationships.
By attaching the stiffening plateau partly peripherally to the opening, which
is enclosed
by the at least one peripheral strip, further partly peripheral strip geometry
is possible,
which is designated as a "further intermediate strip". It is situated between
the outer
edge of the stiffening plateau and the peripheral groove.
CA 02581467 2012-06-08
The further intermediate strip and the peripheral strip preferably have on
their peripheral
extension, a constant width. Due to the structures extending peripherally and
arranged
differently, it is possible to provide changing heights of these structures,
which now
refers to the axial direction of the geometries previously mainly described in
radial
direction.
Observed in cross-section, an up-and-down may be formed, which due to changing
height levels ensures that stiffening occurs which in spite of the large-
dimension
perforation (opening) can extend to the entire lid panel. A step is thus
produced
between in each case two adjacent areas. The step may have a piece running
diagonally at least in sections, which leads into the particular next
structure via
particular radii.
For the height positions, a datum plane may be defined as a reference, which
is placed
on the plane of the perforation, that is, is placed in the plane of the
opening. Other
geometries may be defined in the other height positions relative to this datum
plane.
In such a design, the lid panel, in spite of the destabilising "large
opening", has high
pressure stability and in addition surprisingly controlled `buckling', which
corresponds to
bulging of the lid at excessive internal pressure. Up to normal pressure and
several
times normal pressure, the lid however remains stable so that a safe sealing
on the first
peripheral strip may be achieved by the reclosing device. It lies reliably at
the same
height position (at the same level along its entire periphery), to ensure a
sealing function
with respect to a sealing lip of the reclosing device. In its closing and
sealing position
the lip presses onto the peripheral strip.
The loss of strength may be reliably compensated. The combination of all
stiffening
geometries also achieves controlled `buckling' in the sense of head space
enlargement
by increased internal pressure in the closed can. All requirements of the lid,
the
pressure stability, the considerable dependence on standard closures, the
stackability
and the possibility of facilitating reclosure, indicated in the introduction,
are achieved.
The further edge strip may lie at a different height position than the first
peripheral strip,
preferably deeper. The opening for the said device may
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contain two opposing flat sections to improve assembly. The flat sections
extend radially
inwards.
The plateau height may preferably be placed above the datum plane. If the
plateau is
defined radially inwards and radially outwards by the two peripheral strips
(intermediate
strip and enclosing strip), different height levels of these three regions
achieve improved
stabilisation. Enclosing strip and further intermediate strip may preferably
be placed at
the same height.
Leading-in of the said further intermediate strip, which does not extend fully
peripherally,
but only partly peripherally, just like the stiffening plateau, takes place at
the arm ends
of the stiffening plateau. A leading-in surface, which is designed to be V-
shaped or Y-
shaped, is formed here.
The surface of the or part moon-shaped stiffening preferably has no additional
beads on
its flat extension.
It remains to be said that the modified shell, that is the finished product,
which is
prepared to receive the reclosing device, has a constant opening, which is
also called
perforation, but is not covered by sheet metal. It has no scored or weakened
lines.
Further, no tab (rip-open flap) is attached to the sheet metal.
To compensate for the loss in stiffening in the panel peripherally extending
geometries
are used. In the radial direction an up-and-down occurs along a ray, i.e. a
change of
height positions (change of levels), in particular in that region of the lid
from which the
large opening is offset (centrally offset) and in which the sickle-shaped
plateau area is
introduced without additional stiffenings or beads.
The staggered change in height levels occurs from radially inward to radially
outward,
beginning with the inner edge strip (around the large opening) to the first
enclosing strip,
to the stiffening plateau, to the further intermediate strip and finally via
the peripheral
groove to the folding or mounting edge. Between the stiffening regions which
extend
peripherally over at least 900 preferably diagonal steps are arranged.
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Ball Europe GmbH
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The invention is illustrated and supplemented below using exemplary
embodiments.
Figure 1 is a plan view of a lid as one of several first
examples.
Figure 2 is an axial section A-A through the lid according to
Figure 1.
Figure 3 is a further example with two axial sections A-A, B-B
through the lid offset by 90 .
The lid 1 shown in Figures 1 and 2 as a first example of the invention is
intended for a
conventional drinks can body, which is not shown. The lid is made from sheet
metal
having a thin wall thickness, as generally conventional.
It has a lid panel 10 (as a panel) and a folded edge 11 for connection with an
appropriate container. A damping bead 12 (peripheral groove), which defines
the lid
panel 10 radially outwards, runs along the folded edge. An ironed body is
generally
known and does not need to be described. It has an upper body edge, which is
formed
radially outwards as a flange and is closed by the folded edge 11 by a folding
device
(flanging roller) to form a multiple fold, mostly by the filler.
The folded edge 11 is arranged radially outside of the damping bead 12, which
is also
called "peripheral groove", and projects beyond the lid panel 10 at axial
height. The lid
panel 10, itself also called a "panel", is designed to be circular overall,
but due to the
opening 15 emerging significantly in size, which forms a cutout, essentially
circular
perforation in the lid panel, is still only partly present.
The cylindrical coordinates are used for the description, in radial direction
(horizontal
direction), the extension of the lid panel and in vertical or height
direction, vertically to
the plane E according to Figure 2, the axial direction.
The body itself is not shown, also the reclosing device 90 to be introduced
into the
opening 15 and to be assembled there on the edge, is not shown separately.
The opening 15 in Figure 1 is shown with large dimensions in plan view. It is
arranged
off-centre, relative to its central point M15, which is offset with respect to
the central
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point M10 of the panel 10 by AM. Offsetting is selected to be between 5% and
25% in
several exemplary embodiments, in the exemplary embodiment shown, it is in the
range
between 10% and 12% to 15%, in each case relative to the diameter d10 of the
panel
10, which extends within the peripheral groove 12. As shown dl0 is 2=r1o.
The diameter as an example of an opening dimension dl 5 with 2=r15 of the
perforation
shown here in the example to be essentially circular is smaller than the
diameter dl 0 of
the panel 10, but greater than 50% of this opening dimension, which underlines
the
significant size of the opening 15.
A first and a second peripheral strip surround the opening 15. The first
peripheral strip
16a borders directly on the edge of the opening and has two segment-like flat
sections
15b, 15a at the inner side, which are opposite. They serve to improve assembly
of the
reclosing device 90. The second peripheral strip 16 has a radial dimension
r16, which is
greater than that of the first peripheral strip. It is formed in height
direction above the
plane E.
The plane E is placed in the opening 15 in horizontal direction and forms the
comparison standard for height comparisons. It is the plane of the opening 15,
a two-
dimensional extension within the plane is the opening surface. It describes
the
dimension of the opening 15.
The peripheral strip 16 transfers via a gentle, in particular diagonally
placed step 16' into
the inner peripheral strip 16a. The elevated peripheral ring 16 forms an
annular
pressure and support surface for a sealing and closing lip of the reclosing
device 90
lying entirely at the same level.
The enclosing strip 16 runs completely around the opening 15 and delimits with
respect
to the peripheral groove on the left-hand side in Figure 1. On the right-hand
side in
Figure 1, it forms the limit to a plateau 20 designed to be sickle-shaped or
part moon-
shaped, which extends only partly peripherally around the perforation 15. It
is placed in
that region of the lid panel, from which the opening 15 has been displaced in
centre-
offset manner. It is on the right side of the first axial centre plane
extending vertically to
A-A and through M10.
The partial enclosure is essentially 180 for circular design relative to the
opening 15.
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The peripheral extension of the sickle-shaped plateau 20 is greater than 180 ,
in
particular in the range between 200 and 240 , in particular in the region of
2100 3%,
relative to the periphery of the lid panel and the peripheral groove 12.
This is produced from two arms 21, 22 extending peripherally, which form the
ends of
the stiffening plateau. The stiffening plateau has between these two ends 21,
22, a
bulge 23, which has its greatest radial extension in the central plane A-A and
is tapered
like an arc towards the ends 21, 22.
A further intermediate strip 17, which has essentially the same width on its
peripheral
extension, is provided between the plateau 20 and the peripheral groove 12.
The
peripheral extension corresponds to the extension of the arc of the plateau 20
and is in
any case greater than 90 .
The two peripheral strips 16 and 17 have essentially the same width,
designated in
Figure 1 by r6 and r7. They also have essentially the same height position,
easily seen
in Figure 2 with respect to the plane E.
Both the peripheral strip 16 and the peripheral strip 17 transfers via a
preferably
diagonal step 16" and 17" into the plateau region 20, which lies at a deeper
level,
preferably slightly above the plane E in Figure 2.
An edge 20' of the arc-shaped plateau 20 corresponds to these steps 16" and
17" and
is designed as a preferably diagonal step in each case with at least one short
diagonal
section and two radii to pass over into the in each case adjacent region.
These
diagonals 20' form stiffenings. Also the change between higher and lower
positions
(relative to a height direction), observed in a radial direction, on a "radius
vector" (ray)
from the centre M15, forms a stiffening.
Leading-in of the outer peripheral strip 17 into the inner peripheral strip 16
takes place
in the two lead-in zones 17b, 17a, which are directly adjacent the arm ends
21, 22 of the
plateau 20. Y-shaped or V-shaped zones are formed here, which are wider than
the
particular strip shape of the peripheral strips 16, 17.
To illustrate the dimension of the opening 15, reference should be made to the
radii.
The internal radius r15 of the opening is shown in comparison to the radius
r10 of the lid
panel. The one or the other radius starts in each case from the centre M15 or
M10. The
CA 02581467 2007-03-23
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Ball Europe GmbH
radius rl5 is thus greater than half the radius of rl0, in particular in the
range above
60% between 60% and 65% of the main radius of the lid panel. This describes a
large
opening. The man skilled in the art will understand "large" here in an optical
relation to
the size of break-open regions of drinks can lids normally expected to the
priority date.
5 When the man skilled in the art of cans compares the lengths of the radii,
he would
immediately say concerning r15: "This has been chosen quite large".
Relative to surfaces, it is possible to convert to the surfaces via the radii,
(quadratic
influence), wherein the surface of the opening 15 is greater than 30% of the
panel
--10 surface 10, relative to the original size (without perforation 15). Here
too, a large design
of the opening is round about 40%, preferably between 35% and 45% of the non-
perforated panel surface.
These dimension details are also maintained within the framework of OM central
offsetting, which can be seen from the central points M10 and M15. Here, a
reference to
the diameter dl0 (double main radius) is helpful regarding the size detail.
The central offset AM in various exemplary embodiments, which are not all
shown
separately, lies between 5% and 25%. They change inasmuch as the size of the
opening 15 also has a clearance and range, and the shape of the opening also
has a
clearance and range, which may deviate from the exact circular shape, for
example
polygonal or oval. It is at least approximately polygonal or oval.
In a preferred range, the AM central offset lies between 10% and 15%.
All these measures express that it is - as understood by the man skilled in
the art - a
large opening 15 relative to such openings which are provided or "expected" by
the man
skilled in the art in normal drinks can lids.
3o To compensate the stiffening loss, the geometric shapes are used which have
been
described previously. An up-and-down is produced in radial direction, that is
a change in
height positions (level change), in particular in that region of the lid the
opening 15 is
displaced (centre-offset) from and in which the sickle-shaped plateau surface
20 is
introduced without further additional stiffenings or additional beads.
The change of height positions takes place from radially inwards to radially
outwards (in
a staggered form), starting from the inner edge strip 16a (around the opening
15), to the
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first enclosing strip 16, to the stiffening plateau 20, to the further
intermediate strip 17
and finally via the peripheral bead 12 to the peripheral edge 11. Diagonally
running
steps are preferably arranged between these areas, as previously described
using the
step 20' of the stiffening plateau 20 (as an essentially flat surface having a
large
extension).
The change of height levels of the geometric stiffening shapes 16a, 16, 20,
17, 12, 11
can be seen in section in Figure 2. Each of the stiffening geometries extends
peripherally over at least 90 , as subsidiary lines C-C in Figure 1
illustrate. They define
an angle of 90 and all stiffenings extend far beyond it in peripheral
direction, reaching
180 and even 360 for individual peripheral stiffenings.
The opening 15 is not covered by sheet metal, but is open. It has a free inner
edge 15a.
It is centre-offset (relative to the diameter of the panel) between 5% and 25%
and the
first enclosing strip 16 surrounding it reliably retains the same height
position to facilitate
a sealing function.
The further exemplary embodiment according to Figure 3 follows the first
exemplary
embodiment with two sections A-A, B-B.
It is shown here that in the transverse direction B-B (the central plane), a
change in
height level also takes place from radially inwards to radially outwards, as
far as the
sickle 20 extends. Otherwise than relative to the central plane A-A, the
opening 15 is
symmetrical in transverse direction, so that left and right edge have the same
distance
to the peripheral groove 12. Relative to the central plane B-B, however, there
is
asymmetrie. The perforation 15 with its free edge 1 5a is offset to a large
extent towards
the first side (this side) of the central plane so that on the other side (the
other side)
there is large space for extensive stiffening geometries.
The remaining descriptions regarding Figure 3 may be assumed from the
preceding
exemplary embodiment.
The height difference h1 of outer peripheral strip 17 and inner peripheral
strip 16 is
measured with respect to the deeper-lying sickle-shaped plateau surface 20
according
to the section A-A.
