Note: Descriptions are shown in the official language in which they were submitted.
CA 02671882 2009-06-09
WO 2008/092289 A2
PLASTIC CLOSING DEVICE COMPRISING A CUTTING COLLAR
TECHNICAL FIELD
The invention relates to a plastic closing device
comprising a cutting collar according to the preamble
of patent claim 1. The closing device is in particular
suitable for sealed packages, which contain a free-
flowing content, preferably a beverage.
STATE OF THE ART
A generic closing device is known from EP 1 088 764.
This closing device consists of three parts, namely a
screw cap, a bottom part and a cutting collar. The
bottom part is embodied in a tubular manner and
encompasses at its bottom side a circumferential
flange, by means of which it can be fixed onto a drink
carton. The tubular part forms a pouring spout, which
can be closed by means of the screw cap. The cutting
collar is also embodied in a tubular manner and
encompasses a cutting tooth at its lower end. In the
unopened state of the packaging, the cutting collar is
located within the bottom part, and the screw cap is
screwed onto the bottom part. In the event that the
screw cap is now rotated in order to open the closing
device, the cutting collar rotates as well, thanks to a
follower system, with the cutting collar, thereby
simultaneously moving downwards in axial direction. The
packaging and in particular the film of the packaging
is thereby cut open in a circular manner along a
predetermined breaking line. The follower contact
between screw cap and cutting collar is disconnected
after a predetermined rotation angle, that is, when the
packaging is opened to a sufficient extent. Thereafter,
the screw cap can be completely removed from the
pouring spout and can be placed thereon again, as
CA 02671882 2009-06-09
- 2 -
necessary, so as to perform a closing action, without
once again moving the cutting collar, which projects
into the packaging. The cutting collar and the bottom
part are molded in one piece in a pre-assembly group
configuration, in which they are secured coaxially to
one another by means of radial connecting bridges.
These bridges extend between the top edge of the
cutting collar and the bottom side of the bottom part.
These bridges are broken when the cutting collar is
pushed into the bottom part for the first time.
Theoretically, there is no limit to the form and design
of such closures. In practice, however, they must be
capable of being produced in a injection molding
process. They should furthermore be capable of being
produced as cost-efficiently as possible.
Different types of packaging are known, which can be
opened by means of such self-opening closures. Among
the known packaging, there is, in particular, composite
packaging, which comprises a layer of paper or
cardboard, which is laminated with one or a plurality
of thin plastic and/or metal layers. A typical
composite packaging comprises, e.g., a cardboard layer,
which is provided towards the inside of the packaging
with a thin layer of aluminum, which, in turn, is
provided with a layer of polyethylene (PE). Lately,
packaging which no longer encompasses a cardboard
layer, but which is instead formed from a relatively
thick plastic film, in particular pure PE packaging,
which is, at most, provided with one or a plurality of
very thin barrier layers, is also becoming accepted.
In the production of the packaging, the packaging is
typically weakened, e.g. pre-punched, in the region in
which the closure is later attached so as to make it
possible for the cutting collar to more easily
CA 02671882 2009-06-09
- 3 -
penetrate the packaging wall. Dependent on the design
of the packaging and on the production method, there
are different possibilities for this. In a pure PE
packaging, a circular weakening line can, e.g., be
embodied in the wall having a lower wall thickness. In
a composite packaging, a weakening region is typically
formed in that the cardboard layer is penetrated (e.g.
pre-punched) as completely as possible in a circular
curve-shaped region. In the event that this pre-
punching takes place before the cardboard is coated
with the further layers, the circular disk, which is
cut out of the cardboard, usually is removed prior to
the coating with the further layers, thus creating a
packaging, which, in the region of the subsequent
opening, encompasses a circular region, which only
consists of the thin film layers of aluminum and/or
plastic, but which does not contain cardboard. However,
in the event that the cardboard layer is perforated
only after the coating, the cut-out circular disk
remains connected to the film layers.
Typically, a different type of self-opening collar is
used for each of this differently designed packaging.
In particular, e.g. for a composite packaging having a
circular region in the region of the opening that only
consists of film layers, it is disadvantageous if the
self-opening collar exerts a high axial force onto the
film layers ("pressing"). In this case, there is a
tendency for the film layers to avoid this force by
bulging towards the interior of the packaging. Instead,
such a packaging should be torn open by means of
cutting, if possible. Vice versa, it is advantageous
for packaging in which the cardboard disk is still
present if mainly a pressing force is exerted.
Known self-opening closures furthermore require a very
accurate positioning of the closure on the opening
CA 02671882 2009-06-09
- 4 -
region as provided and prepared by means of a
weakening. In the event that the positioning for such
closures takes place so as not to be accurately
centered, a clean opening of the packaging is often not
ensured.
A closure comprising a self-opening collar is known
from WO 03/002419, which encompasses two cutting
elements, which are arranged so as to follow one
another and which have a triangular basic form.
WO 2006/089440 also shows a self-opening collar
comprising two triangular cutting teeth.
WO 2004/083055 also discloses triangular cutting teeth.
Additionally, a perforating tooth is present herein. In
the event that the cutting teeth did not cleanly cut
through a film of the laminated packaging material, it
is pierced by the perforating tooth.
WO 2007/030965 discloses a self-opening collar
comprising three teeth. Each of these teeth has a
triangular basic form, which is followed by a
reinforcement shoulder. For two teeth, this shoulder is
formed so as to follow the tooth in the direction of
rotation, while for the third tooth it is formed so as
to lead that tooth.
Each of these self-opening collars is optimized for a
certain type of packaging. None of the self-opening
closures thus delivers a satisfactory result for all of
the afore-mentioned types of packaging, but will fail
for at least one type of packaging.
CA 02671882 2009-06-09
- 5 -
DESCRIPTION OF THE INVENTION
It is thus an object of the invention to create a
closing device of the afore-mentioned type that can be
produced in a cost-efficient manner. It is a further
object of the invention to provide a closing device
that is suitable to efficiently pierce different types
of differently designed or differently prepared
packaging. It is a further object of the invention to
specify a closing device that opens different types of
packaging in a satisfactory manner even in the event
that it is not perfectly centered on a weakening region
of the packaging.
A closing device comprising the features of patent
claim 1 solves these objects.
The plastic closing device according to the invention
encompasses a pouring part for fixing onto packaging, a
screw cap, which is adapted to be screwed onto the
pouring part, and a self-opening collar in the pouring
part, which is adapted to be moved downwards towards
the packaging with a screw action in order to open the
packaging. The screw cap has at least one drive element
or driver, which acts on at least one stop element of
the self-opening collar and which, when the screw cap
is first opened, causes the self-opening collar within
the pouring part to move into a lower position towards
the packaging in order to open the latter. When the
pouring part is subsequently closed by the screw cap,
the self-opening collar remains in its lower position.
The self-opening collar comprises at least two cutting
and/or piercing elements, which project downwards,
which are arranged along the periphery of the self-
opening collar and which form a lower edge thereof.
These cutting and/or piercing elements have a
substantially rectangular form. A longitudinal edge,
CA 02671882 2009-06-09
- 6 -
which is relatively long with respect to the direction
of rotation and which projects downwards, interrupts
the rectangular form and forms a triangle, which
projects downwards, thus creating a tip, which projects
downwards. With reference to the direction of rotation
of the collar, the longitudinal edge has at its front a
portion that slopes or declines downwards and that
subsequently rises again, wherein the rising portion is
made so as to be longer and flatter than the declining
portion and runs inclined at a flat angle relative to a
plane that is perpendicular to the longitudinal axis.
This design of the cutting and/or piercing elements
represents the result of an optimization with reference
to fundamentally contradicting demands. It turned out
that a particularly easy and clean opening of the
packaging is attained by means of the proposed form,
namely similarly easy for different types of packaging
(in particular laminated cardboard packaging comprising
different types of weakening as well as PE film
packaging). The leading portion of the longitudinal
edge thus substantially has a cutting effect in
response to the rotation of the collar, while the
entire longitudinal edge, including the rear portion,
also additionally has a pushing effect in response to
the downwards movement.
The rising and/or declining portion can be straight or
can be curved. Preferably, it is considerably longer
than the rising portion and preferably has a length,
which is at least 2.5 times the length of the rising
portion. Preferably, the rising portion opens an angle
of at least 40 , particularly preferred approx. 50 to
the horizontal (thus to a plane, which is perpendicular
to the axis of rotation), all-over, while the angle of
the declining portion to the horizontal is preferably
less than 30 , particularly preferably less than 20 ,
CA 02671882 2009-06-09
- 7 -
all-over. An obtuse angle, that is, an angle of more
than 90 degrees, is embodied at the location between
the rising portion and the declining portion of the
longitudinal edge.
Preferably, the longitudinal edge projecting downwards
forms, at least in its rising portion, a cutting edge,
that is, the self-opening collar is embodied in this
region so as to taper in a blade-like manner towards
the longitudinal edge. The tearing of the packaging is
thus facilitated. Preferably, a cutting edge is also
provided in the declining portion. Film material, e.g.,
which stretches elastically across the longitudinal
edge, can thus also be torn efficiently in this region.
Preferably, the cutting edge is provided on an inner
peripheral surface of the self-opening collar. In other
words, the self-opening collar preferably tapers
towards the longitudinal edge only at its outer
periphery in order to thus form the cutting edge, while
the inner circumference in the region of the
longitudinal edge is constant. The cut material is thus
displaced outwards, which adds to a clean cross section
of the cut-out material disk of the packaging.
Preferably, all of the cutting and/or piercing elements
project downwards to the same extent. They thus contact
the weakening region of the packaging at the same time
and perforate said packaging at a plurality of
locations at the same time. Even in the event that the
perforation should not succeed at a location, an easy
opening is ensured. Furthermore, a relatively large,
even pressure is thus exerted onto the weakening
region, which is particularly advantageous for certain
types of packaging.
CA 02671882 2009-06-09
- 8 -
In order to attain the most even force distribution,
the cutting and/or piercing elements (32a-32e) are
preferably arranged along the periphery so as to be
distributed at the same distance.
Additionally, the self-opening collar can encompass at
least one hold-down element which forms the lower edge
together with the cutting and/or piercing elements and
which serves the purpose of pressing the detached
material disk of the packaging downwards in order to
prevent that said material disk hinders the pouring.
The hold-down element is then arranged so as to follow
the cutting and/or piercing elements in the direction
of rotation.
In this case, the cutting and/or piercing elements are
preferably arranged so as to be distributed
successively and at the same distance along the
periphery, and the distance from the hold-down element
to the first cutting and/or piercing element in the
direction of rotation is preferably greater than the
distance of the cutting and/or piercing elements among
one another.
In the event that a hold-down element is available, the
self-opening collar preferably comprises three to five,
in particular four cutting and/or piercing elements.
Without hold-down element, it is advantageous when the
self-opening collar encompasses four to six, in
particular five cutting and/or piercing elements. With
a smaller number, the force distribution is less even
and the material thickness of each individual cutting
and/or piercing element must be increased considerably,
which increases the production price. A larger number
of such elements, in turn, has the effect that each
individual element becomes smaller, which is also
disadvantageous in view of the stability. With a number
CA 02671882 2009-06-09
- 9 -
of elements that is too large, the pressing force
exerted by each individual element furthermore becomes
too small and it is no longer possible to attain a
clean cutting effect. In essence, the optimal number is
the result of a drawn-out optimization in view of the
different and partly contradictory demands that must be
fulfilled by the self-opening collar in order to render
it suitable for different types of packaging.
For guiding purposes, the self-opening collar
preferably has an external thread, which cogs with an
internal thread of the pouring part so that the self-
opening collar rotates during its downwards movement.
The pitch of the external thread is preferably chosen
in such a manner that the self-opening collar performs
a rotation of less than 360 degrees, in particular 300
degrees, in response to the unscrewing of the screw
cap.
Preferably, only a single drive element is provided on
the screw cap. Preferably, only a single stop element
is accordingly provided on the self-opening collar as
well. Preferably, this stop element is located in the
vicinity of a cutting and/or piercing element that is
foremost in the direction of rotation of the collar.
However, a plurality of stop elements, which are
arranged so as to be distributed along the periphery,
can also be available, wherein the driver only engages
with one of them.
In the case of a single drive element or driver, the
closing device is designed in a very simple manner.
This minimizes the production costs. Material can, in
particular, be saved for the closure, because the
driver system is reduced to an absolute minimum. Thanks
to the simple form of the closing device, its
CA 02671882 2009-06-09
- 10 -
production is also simplified and the waste of closures
not conforming to quality is relatively low.
Preferably, the driver has a driver edge, which runs in
axial direction. The driver edge then preferably
encompasses a stop surface, which slopes relative to
the radial direction. In particular, the driver can be
embodied in a tooth-shaped manner with the
perpendicularly running driver edge and a back edge
comprising an angle of slope of maximally 45 .
Preferably, the driver has a height corresponding
approximately to the height of the pouring part. The
stop element can be a lug projecting from an inner wall
of the self-opening collar, which comprises an edge
running in axial direction and which extends only
across a part of the height of the self-opening collar.
The lug can then have a undercut relative to the radial
direction.
Further advantageous embodiments become evident from
the dependent patent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The subject-matter of the invention will be exemplified
below by means of preferred embodiments, which are
illustrated in the enclosed drawings.
Figure 1 shows a longitudinal section through a closing
device according to a first embodiment in a state prior
to its first use;
Figure 2 shows the device according to Figure 1 in
response to the screw cap having been unscrewed;
Figure 3 shows a side view of the device according to
Figure 2;
CA 02671882 2009-06-09
- 11 -
Figure 4 shows a view of the closure according to
Figure 2 from below, mounted onto a packaging;
Figure 5 shows a longitudinal section through the
pouring part and the self-opening collar of the device
according to Figure 1 after its production;
Figure 6 shows a perspective illustration of the device
according to Figure 1 from below;
Figure 7 shows a perspective illustration of the device
according to Figure 1 from the side;
Figure 8 shows a view of the device according to Figure
1 from below;
Figure 9 shows a side view of the pouring part and of
the self-opening collar according to Figure 1;
Figure 10 shows a section through A-A according to
Figure 9;
Figure 11 shows a longitudinal section through a
closure according to the invention according to a
second embodiment;
Figure 12 shows a perspective illustration of the
closure according to Figure 11 and
Figure 13 shows a view of the closure according to
Figure 11 from below, mounted onto a packaging.
WAYS OF CARRYING OUT THE INVENTION
Figures 1 to 10 illustrate an exemplary embodiment of a
closing device or of a self-opening closure. Such
closures are fixed onto packaging with free-flowing
CA 02671882 2009-06-09
- 12 -
content, in particular onto drink cartons made of
cardboard comprising a film on the inside thereof. In
this region, the packaging preferably already
encompasses a pouring opening, which is predefined, but
which is still closed in an airtight manner.
Preferably, the cardboard is already perforated or
otherwise weakened, but the film arranged therebelow is
still intact.
The device is made of plastic in a injection molding
process, wherein the individual parts can be
manufactured from the same or from a different plastic.
As can be seen in Figure 1, the device substantially
comprises a pouring part 1, a screw cap 2 and a self-
opening collar 3. Preferably, a tamper-proof strip 4 is
additionally available, which is preferably produced in
one piece with the screw cap 2. Pouring part 1 and
self-opening collar 3 are preferably also produced
together in one piece. However, it is also possible to
manufacture them separately from one another.
The pouring part 1 substantially consists of a tube-
shaped pouring spout 10 having a continuous pouring
opening and a flange 13, which extends outwards from
the pouring spout 10 and which is integrally molded on
a lower end of the pouring spout 10. This flange 13 is
welded onto the packaging or is otherwise fixed thereon
so that the pouring spout 10 comes to rest above the
predefined pouring opening of the packaging.
The pouring spout 10 encompasses an external thread 12
and an internal thread 14. As is described further
below, bars 15 comprising projecting, undercut
retaining lugs 15' are arranged in the lower region of
the pouring spout 10 above the flange 13.
CA 02671882 2009-06-09
- 13 -
The screw cap 2 preferably has a cylindrical jacket
wall 21 and an approximately flat top surface 20. The
cap 2 can be screwed onto the external thread 12 of the
pouring part 1 by means of an internal thread 22. The
jacket wall 21 is connected to the tamper-proof strip 4
via predetermined breaking points 23.
A circumferential sealing lip 26, which in the closed
state of the cap 2 abuts on the inner side of the
pouring spout 10 in a resilient manner, preferably
projects downwards in the inner region of the cap 2.
The cap 2 encompasses a single driver 24, which
projects inwards or downwards, respectively, and which
is preferably integrally molded onto the inner side of
the top surface 20. Preferably, the driver 24 has a
triangular basic form, wherein it is curved along a
circle that is concentric to the internal thread 14. A
driver edge 14 runs in axial direction, wherein it
preferably has a stop surface that slopes towards the
radial direction, thus forming a rear-engaging element.
A back follows the driver edge in the opening direction
of rotation of the cap 2, wherein the back has an angle
of inclination of maximally 45 . The height of the
driver 24 corresponds approximately to the height of
the pouring part 1, in particular of the pouring spout
10.
The self-opening collar 3 has a hollow-cylindrical form
and has a continuous opening. It substantially consists
of a ring 30 comprising an external thread 31 and of
cutting and/or piercing elements 32a-32e, which
protrude from the ring 30 downwards in approximately
perpendicular direction. These cutting and/or piercing
elements 32a-32e are distributed along the periphery of
the self-opening collar 3 and are arranged at a
distance 33 to one another and form a lower edge
CA 02671882 2009-06-09
- 14 -
thereof. Furthermore, at least another down-hold
element 35 can be available at this edge. These
elements will be described in more detail below.
The collar 3 encompasses at least one, preferably
exactly one stop element 36, as can be seen in Figure
2. The stop element 36 is a lug projecting from an
inner wall of the self-opening collar 3, which
encompasses an edge running in axial direction and
which preferably extends only across a part of the
height of the self-opening collar 3. Preferably, the
lug encompasses a stop surface that is inclined
relative to the radial direction. The lug preferably
extends in the region of the external thread 31,
wherein the external thread extends along a greater
height than the lug. The stop element 36 is preferably
arranged in the direction of rotation of the collar 3
in the region of the first cutting and/or piercing
element 32a, wherein it can be arranged in the front or
rear portion thereof or therebetween.
In Figure 1, the cap 2 is screwed onto the pouring part
1 and the self-opening collar 3 is located in the
pouring spout 10, wherein it does not project downwards
beyond said pouring spout 10 or the flange 13,
respectively. The tamper-proof strip 4 is intact. This
is the situation as it is at hand prior to the first
use of the closure. In this position, the closure can
be mounted onto the packaging.
In the event that the cap 2 is unscrewed, the driver 24
abuts to the stop element 36. This can be seen in
Figure 6. In the event that the surfaces thereof are
embodied so as to be inclined, at least a partial form
closure takes place moreover, which reinforces the
connection between cap 2 and collar 3.
CA 02671882 2009-06-09
- 15 -
The external thread 31 of the collar 3 cogs with the
internal thread 14 of the pouring part 1 so that the
collar 3 rotates downwards with a screw action within
the pouring spout 10 when the cap 2 is first unscrewed.
When the cap 2 is removed, the engagement between
driver 24 and stop element 36 is disconnected.
In Figure 2, the cap 2 is removed, the predetermined
breaking points 23 to the tamper-proof strip 4 are
broken and the collar 3 has moved downwards so that the
cap 2 is now held in the lower region of the pouring
spout 10 only with its upper part, but projects
downwards beyond the flange 13 with its teeth 32a-32e.
This is the situation as it is at hand after the first-
time opening of the closure.
This general situation is once again illustrated in
Figure 4, wherein it can be seen that a section D,
which predefines the pouring opening of the packaging
K, is not completely detached, but remains fixed
thereon via a small partial circle. Said section D,
however, is held in an open position by at least one of
the cutting and/or piercing elements 32e.
The collar 3 now remains in this lower position, even
in the event that the cap 2 is attached again and
screwed tightly.
As can now be seen in Figure 3, this embodiment
encompasses a total of five cutting and/or piercing
elements 32a-32e. These are preferably made to have the
same height. These elements are arranged so as to be
distributed across the periphery of the collar 3 at the
same distance.
Preferably, they are formed to be identical and to have
the same height. They have a substantially rectangular
CA 02671882 2009-06-09
- 16 -
form, wherein a longitudinal edge projecting downwards
interrupts the rectangular form in each case. The edge
is inclined, wherein the height of the element in the
direction of rotation of the collar 3 decreases
rearwards. The longitudinal edge is relatively long so
that it is greater than the distances 33 between the
elements. Preferably, it is at least twice as long as
the distance 33 located therebetween.
In this example, the longitudinal edge is embodied so
as to be relatively blunt so that the elements rather
or exclusively act as pushers or piercers and not as
cutting elements.
However, as is illustrated in Figures 11 to 13, they
can also be designed as cutting elements, without
having to considerably change their basic form. In the
further preferred exemplary embodiment illustrated
herein, a longitudinal edge that initially declines or
slopes downwards in the direction of rotation of the
sleeve 3 and which subsequently rises is formed instead
of the longitudinal edge according to Figure 3, which
runs straight, so that a tip is formed that projects
downwards. The rising portion is thereby embodied so as
to be longer and flatter than the declining portion,
which acts as cutting edge. In the instant example, the
length of the rising portion is approximately three
times the length of the declining portion. The
declining portion subtends an angle of approx. 50 to
the horizontal (that is, to the plane that stands
perpendicularly on the direction of rotation), while
the rising portion forms an angle of only approx. 12
to the horizontal. An obtuse angle, which here is
approx. 118 , is formed between the rising and the
declining portions. The declining as well as the rising
portions are designed in a blade-like manner as a
cutting edge. For this, the self-opening collar tapers
CA 02671882 2009-06-09
- 17 -
towards the cutting edge or approaches the cutting edge
in a blade-like manner, respectively. In the instant
case, this tapering takes place only at the outer side
of the self-opening collar. The inner jacket surface of
the self-opening collar, however, is cylindrical in the
region of the cutting edge. Through this, the cutting
edge displaces the cut material outwards in response to
the cutting and thus contributes to a clean cross-
section, on the one hand.
In the example of Figures 11 to 13, a total of four
cutting and/or piercing elements 32a-32d are provided,
which are followed by a single hold-down element 35.
All of the cutting elements 32 are designed to have the
same size and the same form. The hold-down element 35
also has approximately the same width and length,
respectively, but does not have a cutting tip and is
thus smaller. The distance from the hold-down element
35 to the first cutting and/or piercing tooth 32 in the
direction of rotation is greater than the distance of
the teeth 32 among one another.
An advantage of these two embodiments is that they need
no longer be accurately positioned on the predefined
pouring opening. Thanks to their cutting and/or
piercing elements, which are relatively long or wide in
the direction of rotation of the collar 3, they can
also contact the section at a distance to the
perforation and can still exert a sufficient amount of
pressure in order to disconnect the section D from the
packaging. Furthermore, a relatively steep thread can
be chosen between collar 3 and pouring spout 10 thanks
to these elements so that a rotation of less than 360 ,
in particular of less than 300 , is sufficient to open
the closure and to push down the section D.
CA 02671882 2009-06-09
- 18 -
Figure 5 illustrates a possibility for producing such a
closure. The cap is molded separately, the collar 3 and
the pouring part 2, however, are produced in one piece.
The collar 3 thereby projects partially beyond the
pouring spout 2 on top, wherein it is connected to the
pouring part 2 via connecting bridges 5. After the part
has been molded, the collar 3 is pressed completely
into the pouring spout 10, wherein the connecting
bridges 5 break.
Figures 7 to 10 illustrate a preferred embodiment of a
first opening identification. This type of
identification can be used not only for this closure
but for all closures that comprise a pouring spout
having a flange and a cap that can be screwed onto the
spout.
Starting at the pouring spout 10, a plurality of bars
15, which run parallel to a tangent at the pouring
spout 10 and parallel to one another, are integrally
molded on the upper side of the flange 13. Preferably,
their free ends are located on a common circle, which
runs concentrically to the outer periphery of the
pouring spout 10. One bar 15 or a plurality of bars 15,
here two, can also run perpendicular to the remaining
bars 15. This can be seen in Figure 10. The free ends
form undercut retaining lugs 15, as can be seen in
Figure 9.
As is illustrated in Figure 7, the tamper-proof strip 4
is injection molded at the cap 2 via predetermined
breaking bridges 23, wherein said tamper-proof strip 4
preferably completely rotates around the cap 2. In the
state in which the closure has never been opened, the
retaining bars 40 of the tamper-proof strip 4 engage
with the retaining lugs 15' and prevent a mutual
rotation of cap 2 and pouring part 1, as can be seen in
CA 02671882 2009-06-09
- 19 -
Figure 10. In response to a rotation of the cap 2, the
predetermined breaking bridges 23 are disconnected by
axial drag and the tamper-proof strip is completely
disconnected from the cap 2.
Preferably, connecting bridges 6, which are preferably
wider than the bars 23, are still available between cap
2 and tamper-proof strip 4. Preferably, they are
arranged evenly along the periphery of the cap, as can
be seen in Figure 8, for example. In the example
illustrated herein, three such bridges 6 are available,
but their number can vary. These bridges facilitate and
shorten the injection molding process, because a
relatively large amount of material can be transported
via these bridges. These bridges 6 are broken after the
production of the cap and preferably prior to the
mounting of the closure. Preferably, they are cut
through by means of a knife or a laser beam. Such
connecting bridges can be used for all embodiments.
They can furthermore be used for all individual
components, which are injection molded together. This
production method is not limited to the closures
according to the invention as described herein.
Additional forms of the self-opening collar 3, in
particular of the cutting and piercing elements, are
possible. The number of teeth can also be varied.
Furthermore, the above-mentioned external and internal
threads can be continuous or only partial threads.
LIST OF REFERENCE NUMERALS
1 pouring part
pouring spout
12 external thread
13 flange
14 internal thread
CA 02671882 2009-06-09
- 20 -
15 bar
15' retaining lug
2 screw cap
20 top surface
21 jacket wall
22 internal thread
23 predetermined breaking points
24 driver
26 sealing lip
3 self-opening collar
30 ring
31 external thread
32a first piercing element
32b to
32e second to fifth piercing element
33 distance
34 second cutting tooth
35 hold-down tooth
36 stop element
4 tamper-proof strip
40 retaining bar
connecting bar
6 connecting bridge
K cardboard packaging
D section
