Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02989058 2017-12-11
RECLOSABLE TEAR-OPEN LID
The invention relates to a resealable tear-off lid for beverage cans or
similar containers.
Moreover, the invention relates to a beverage can with such a tear-off lid, a
grip tab for
such a tear-off lid, and a method for manufacturing a corresponding grip tab.
Tear-off lids typically have a central lid plane within which a breakout
portion is arranged
that is defined, for example, by a line of weakening that can be broken in
order to open
the lid, so that the breakout portion uncovers an opening, for example a
drinking opening.
A grip tab is typically provided for opening the breakout portion that is
generally connect-
ed in a swiveling manner to the lid plane, for example by means of a rivet
formed from the
lid plane. Such a grip tab typically has a grip portion and an opener portion.
The grip tab
io is shaped such that, when the grip portion is lifted, the opener portion
presses against the
breakout portion and breaks a line of weakening that''defines the breakout
portion. Such
tear-off lids are generally known.
Moreover, there are concepts in which the resealing of the opening defined by
the
breakout portion occurs as a result of the grip portion of the grip tab being
swiveled or
twisted over the opening and subsequently onto or into the opening such that
the opening
is sealed again. In that case, the swiveling or twisting occurs about a swivel
axis or axis of
rotation which, at least in the original, unused state of the breakout lid,
extends approxi-
mately perpendicular to the lid plane. Such a concept is described, for
example, in WO
2004/056667 Al.
It is the object of the invention to improve a corresponding tear-off lid.
According to the invention, a tear-off lid made of metal sheet is proposed
which has a
central lid plane and, within that, a breakout portion, as well as a grip tab
made of metal
sheet that can be swiveled about a swivel axis extending at least
approximately perpen-
dicular to the lid plane and has an opener portion on one side of the swivel
axis and a grip
portion on the opposing side of the swivel axis. The grip portion is shaped
such that, upon
opening the breakout portion, it can be rotated over an opening created
thereby and
tightly seal the opening. The opening is enclosed by an outer contour that
forms the edge
of the opening. The metal sheet that forms the grip portion has apertures, and
an elasto-
mer seal is provided on a bottom side of the grip portion facing toward the
lid plane that is
connected in a form-fitting manner to the grip portion and extends through the
apertures.
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CA 02989058 2017-12-11
The elastomer seal is preferably part of an integrally formed elastomer body
that extends
both on the bottom side of the grip portion facing toward the lid plane
(forming the elas-
tomer seal there) and on the top side of the grip portion facing away from the
lid plane.
By virtue of the fact that the elastomer seal, or the elastomer body, extends
through the
apertures in the metal sheet forming the grip portion, the elastomer seal is
reliably con-
nected in a form-fitting manner to the grip portion and can neither be lost
nor slip, inde-
pendently of whether the elastomer seal is additionally connected to the grip
portion by
other means, for example through adhesion. This means that, in order to
produce a
suitable grip tab, no adhesion promoter or other agent creating an adhesion
between
elastomer seal and the metal sheet of the grip portion is required in order to
reliably
connect the elastomer seal to the grip portion; rather, the elastomer seal is
already con-
nected in a defined manner to the grip portion in that the elastomer body
forming the
elastomer seal extends on both sides of the grip tab (bottom and top side) and
through
the apertures in the metal sheet of the grip tab. Such an elastomer body can
be produced
by injection using the injection-molding process.
Due to the fact that the elastomer body and hence the elastomer seal is
connected me-
chanically in a form-fitting manner to the grip portion, no great
consideration need be
taken of other characteristics (besides the mechanical characteristics), such
as adhesion
characteristics, etc., in selecting the elastomer. Instead, the elastomer can
be selected
entirely based on mechanical requirements. There is complete freedom in the
design of
the seal geometry as well.
What is more, such an elastomer seal is cost-effective to manufacture in
conjunction with
such a grip portion, because the apertures for the elastomer body can be
created in one
work step with other apertures of the grip tab, such as the central openings
for the rivet,
for example. Nor does the injection molding of the elastomer body require more
effort
than the injection molding of another type of seal, as it is not necessary
with the elasto-
mer body according to the invention to take any preparatory measures to
improve adhe-
sion.
The apertures are preferably arranged along a contour of the grip portion
corresponding
more or less to an outer contour of an opening to be produced by opening the
breakout
portion, i.e., to the outer contour and hence the edge of what will later be
the drinking
opening. The apertures are thus located where stress is presumably most
strongly ap-
plied on the elastomer seal during use. This makes it possible to implement
the elastomer
seal in the form of a relatively thin elastomer body.
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Preferably, between 2 and 24 apertures are provided along this contour, with a
number
between 4 and 12 or 4 and 8 apertures being preferred. Just 2 apertures will
enable
achievement of a defined positioning of the elastomer seal in relation to the
grip portion
such that no rotation of the elastomer seal is permitted, for example. A
greater number of
apertures may counteract deformation of the elastomer seal, if required.
The apertures are preferably approximately circular in shape and have a
diameter of 2
mm or less. Alternatively, the apertures can be slits that are opened by the
injection
pressure upon injection molding of the elastomer body.
The elastomer seal preferably forms an unbroken surface on the bottom side of
the grip
portion, with the unbroken surface being structured such that it completely
covers an
opening to be produced by opening the breakout portion when the grip portion
seals this
opening. This results in an unbroken elastomer surface that completely covers
the drink-
ing opening when the lid is in the closed state. The only contact surface
between the grip
portion acting as a seal and the drinking opening is therefore that between
the edge of
the drinking opening and the elastomer seal. It is advantageous if the
elastomer seal has
a sealing ridge there ¨ that is, along the outer contour of the opening to be
produced by
opening the breakout portion.
The elastomer body preferably extends on the outer side of the grip portion
facing away
from the lid plane beyond several of the apertures. As a result, the elastomer
body cannot
detach from the grip portion without destroying the elastomer body.
Preferably, on the outer side of the grip portion facing away from the lid
plane, the elas-
tomer body forms a sign, e.g., a graphic symbol, that is recognizable to the
user. It is thus
unnecessary to imprint a symbol that may be desired into the metal sheet
forming the grip
portion. Such an imprinting step can thus be omitted.
Preferably, the grip tab can be swiveled over a rivet shaped from the lid
plane and is
rotatably connected thereto. Such a connection between grip tab and lid plane
is inher-
ently known, but it has special importance in the case of a grip tab whose
grip portion is
used simultaneously as a closure for the drinking opening and, in particular,
must permit
an appropriate rotation.
The tear-off lid and the grip tab are preferably made of aluminum sheet. This
material has
proven to be the most suitable for the manufacture of lid and grip tab.
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CA 02989058 2017-12-11
According to another aspect of the invention, a beverage can with a can body
and a tear-
off lid is proposed, with the tear-off lid being connected tightly over its
entire periphery to
the can body and being a tear-off lid of the type described herein. The
connection be-
tween tear-off lid and can body is preferably achieved with a double seam and
is hermeti-
cally tight.
According to another aspect of the invention, a grip tab made of metal sheet
for a tear-off
lid of the type described herein is proposed. The grip tab has a grip portion
that is de-
signed to seal a drinking opening in a tear-off lid and has an elastomer seal
that is part of
an integrally formed elastomer body that extends through apertures of the grip
portion
and, as a result of this, is connected in a form-fitting manner to the grip
portion.
Preferably, such a grip tab is produced by placing a finished sheet-metal part
forming the
grip tab into an injection mold and injecting a preferably thermoplastic
elastomer against
the sheet-metal part such that an integrally formed elastomer body is formed
that pene-
trates through apertures in the sheet-metal part.
The invention will now be explained in further detail on the basis of an
exemplary embod-
iment with reference to the figures.
Fig. 1 shows a two-part beverage can with a can body and a lid;
Fig. 2 shows a tear-off lid according to the invention;
Fig. 3 shows a top view of a grip tab for a tear-off lid according to
the invention;
Fig. 4 shows a bottom view of a grip tab for a tear-off lid according to
the inven-
tion;
Fig. 5 shows a partial section through the grip tab and the injection-
molded elas-
tomer body;
Fig. 6 shows an alternative design variant of a grip tab for a tear-off
lid according
to the invention; and
Fig. 7 shows another alternative design variant of a grip tab for a tear-
off lid ac-
cording to the invention.
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Fig. 1 shows a beverage can 10 with a can body 12 and a lid 14 that is
connected tightly
by means of a double seam to the can body 12. Can body 12 and lid 14 are each
made of
metal sheet. The can body can be made of aluminum sheet or tinplate, whereas
the lid 14
is preferably made of aluminum sheet.
As can be seen from Fig. 2, the lid 14 has an ordinary lid plane 20 within
which a
breakout portion 22 is defined by a line of weakening 24. The line of
weakening 24 de-
fines the edge and hence the outer contour of the drinking opening that is
formed upon
breaking-open of the breakout portion 22. A grip tab 28 is connected by a
rivet 26 to the
lid plane 20 of the lid 14.
The grip tab 28 has a grip portion 30 and an opener portion 32 between which a
rivet
opening 34 for the rivet 26 of the lid 14 is located. The grip tab 28 is
formed in an inher-
ently known manner from a piece of aluminum sheet. An elastomer body 36, which
forms
an elastomer seal 38 on the bottom side of the grip portion of the grip tab
28, is injection-
molded against the grip tab 28. The elastomer body 36 extends through
apertures 40 in
the metal sheet forming the grip portion 30 and forms, on the top side of the
grip portion
30, an integrally formed, closed and circumferential elastomer ridge 42. The
elastomer
body 36 is connected integrally and by means of injection molding to the metal
sheet of
the grip tab 28.
To create the grip tab 28, the completely formed metal sheet of the grip tab
28 is placed
into a corresponding injection mold, and the elastomer body 36 is then
injected.
As can be seen particularly from Fig. 5, the elastomer body 36 extends through
the
apertures 40 in the metal sheet of the grip portion 30, so that the elastomer
seal 38 on the
bottom side of the grip portion 30 and the elastomer ridge 42 on the top side
of the grip
portion 30 are integrally connected to one another and the elastomer body 36
can no
longer detach from the metal sheet of the grip tab 28.
Adhesive forces between the elastomer body 36 in the metal sheet of the grip
tab 28 are
not necessary, so no adhesion promoter is required for the joining of the
elastomer body
36 with the metal sheet of the grip tab 28.
Rather, the connection between the elastomer body 36 and the grip of the sheet-
metal
tab 28 is achieved by purely mechanical means by positive locking, with the
elastomer
body 36 extending through the apertures 40 in the metal sheet of the grip tab
28.
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As can be seen from Figs. 3 and 4, a total of six apertures 40 are provided in
the depicted
exemplary embodiment that are arranged along a contour corresponding at least
approx-
imately to the outer contour of the breakout portion 22, which, in turn, is
defined by the
line of weakening 24. Instead of a total of six apertures, it is also possible
to provide only
at least two apertures, but also up to 24 apertures. Fig. 6 shows an exemplary
embodi-
ment of a grip tab 28' with a total of 24 apertures 40'.
The arrangement of the apertures 40 along the outer contour of the breakout
portion 22 is
advantageous because, in the resealed state of the lid 14, the elastomer seal
38 is in-
tended to rest tightly along the outer contour of the breakout portion 22
against the edge
of the drinking opening produced by breaking open the breakout portion 22. For
this
purpose, the elastomer seal 38 formed by the elastomer body 36 also has a
sealing ridge
44 that extends along the outer contour of the breakout portion 22 and is
reliably held in
place by the apertures 40 that are also arranged along the sealing ridge 44.
As can be seen particularly from Fig. 4, the elastomer seal 38 forms an
unbroken surface
that encloses the sealing ridge 44 and is completely enclosed within the
surface enclosed
by the sealing ridge 44. This has the effect that, when the lid 14 is in the
resealed state, a
drinking opening formed after the breaking-open of the breakout portion 22 is
completely
covered by the elastomer seal 38.
Alternatively, instead of a completely closed elastomer seal 38, it is also
possible for only
a sealing ridge 44' to be provided along the edge of the drinking opening
(that is, along
the outer contour of the breakout portion 22). Such an alternative sealing
ridge 44' would
then have not only a sealing surface associated with the edge of the drinking
opening, but
also a second sealing surface that faces toward the bottom side 46 of the grip
portion 30
of the grip tab 28. A corresponding exemplary embodiment is illustrated in
Fig. 7.
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CA 02989058 2017-12-11
List of reference symbols
beverage can
12 can body
14 lid
5 20 lid plane
22 breakout portion
24 line of weakening
26 rivet
28 grip tab
10 30 grip portion
32 opener portion
34 rivet opening
36 elastomer body
38 elastomer seal
40 apertures
42 elastomer ridge
44, 44' sealing ridge
46 bottom side of the grip portion 30
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