Note: Descriptions are shown in the official language in which they were submitted.
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WO 92/00892 1 PCT/EP91/01283
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A 8EALI~G CL08URE FOR A BOTTLE OR T~E LIRE,
AS WELL AS A PROCE88 FOR T~E MaN~FACT~RE OF T~E 8AME.
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The invention relates to a sealing closure of the type stated in
the introductory portion of claim 1, for a bottle or the like, as
well as to a process for the manu~acture of the same.
A sealing closure is already known, from th- German patent number
DE-PS 36 42 998, in which, in addition to the radial, frontal
sealing surface, axial sealing surfaces, into which the sealing
- mass of the sealing extends, are also provided in the area of the
edge of the aperture of a bottle. The sealing part is deep-drawn,
and extends around the edge of the aperture of the bottle, in order
to thereby form the external, axial sealing surface. The essential
point of this known sealing closure consists of the fact that the
sealing part is, in at least one partial area -- that is to say, at
the point of the transition from the sealing part to the support
part -- not deep-drawn up to the lateral edge of the aperture of
the neck of the bottle, but is, rather, removed out from the said
deformation. In this manner, an impeded sealing section should be
created in the non-deformed portion, which section should., because
of its shortness, lead to a low level of tightness. In this
manner, the escape of excess pressure is favored. The escape of
the excess pressure is, in such a type of sealing closure, however,
less dependent on the sealing section than it is on the support
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WO 92/00892 2 PCT/EP91/01283
pressure of the sealing. In this known sealing closure, however,
this is uniform over the entire edge of the aperture. The desired
effect of an excess pressure valve is thus only attained to a very
incomplete degree.
A sealing closure for a bottle or the like is also already known,
from the German patent number DE-PS 37 44 292, which has a cap-
shaped support part, on which a projection or collar, which is
directed inwardly in order to provlde for the engagement of an
external bulge of the neck of the bottle, is positioned. This sup-
port part is connected, by means of an elastic element, with a
sealing part, which has a ring-shaped sealing surface for the fit-
ting of the frontal surface of the neck of the bottle. The support
part has a catch unit for the defined contact fitting of the sup-
port part with the edge of the neck of the bottle. Since the seal-
ing part likewise abuts with the edge of the neck of the bottle,
the reciprocal position of the support part and the sealing part is
thereby precisely defined. Since the elastic element for the pre-
stressing of the sealing part is located between these two units,
the degree of the prestressing of the elastic element is thereby
also precisely defined and, thereby, the pressure at which the
sealing part rises up and, therefore, opens the excess pressure
valve.
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WO 92/00892 3 PCT/EP91/01283
A screw sealing closure of the type which is stated in the intro-
ductory portion of claim 1 is already known from the US patent
number 40 89 434, in which a sealing of foam material, which has
different thicknesses in its cross-section in diametrical direct-
ions, is positioned between the base of the screw cap and the
frontal edge of the neck of the bottle. When the cap is screwed
on, therefore, the areas of greater thickness are compressed more
intensely than the areas of smaller thickness. In the areas of
lesser thickness, the sealing force is, therefore, lower, and these
areas are intended to serve as an excess pressure valve. The
opening pressure hereby depends on the compression of the entire
sealing, and is consequently not independent of the torque of the
screwing. If the screwing on of the cap is carried out with too
little torque, the areas of slighter thickness are not brought to
contact fitting, and the sealing is not tight. If the sealing is
screwed on with a force which is too great, then the contact force
is also too great in the area of the slighter thickness, so that
the opening pressure is correspondingly also great, which entails
the danger of the explosion of the bottle. There is also the
specific disadvantage that the greater portion of the torque is,
when the cap is screwed on, eliminated when the areas of the seal-
ing which have the greater thickness are compressed, and their sur-
face is, at the same time, significantly greater than the surface
of the areas of lesser thickness, so that the increased rise in the
torque can scarcely be determined because of the additional com-
pression in the area of the points of lesser thickness of the seal-
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WO 92/00892 4 PCT/EP91/01283
ing, particularly if the cap is screwed on by hand. The screwing
on of the cap by hand is, however, the normal case under practical
conditions, and this is decisive. The danger of an explosion
therefore additionally exists in the normal case.
A pressure release sealing for a sealing closure which is similar
to the US patent number 4 089 434 discussed above is already known
from the German patent disclosure statement number DE-OS 1 432 224,
whereby the difference conslsts of the fact that the areas of
smaller thickness of the sealing are only located on two short
points on the circumference which are diametrically opposed to one
another. The largest portion of the sealing has the greater thick-
ness. The disadvantages described above are thus even greater than
before.
Cap-shaped sealing closures with excess pressure safety mechanisms
are already known from the US patent number 3 114 467, as well as
from the German utility model number 8 122 918 O-l, in which a flat
sealing disk is positioned within the base, behind which recesses
are positioned at a number of points on the circumference. If sucl
a cap is screwed on to the neck of a bottle, and if pressure arises
within the bottle, then the edge of the disk-shaped sealing rises
up slightly at those points at which the recesses within the base
of the cap are located, so that excess pressure can escape. One
disadvantage of these known screw sealing closures consists of the
fact that, within the area of the recesses in the base of the screw
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Wo 92/00892 5 PCT/EP91/01283
caps, absolutely no contact pressure of the edge of the sealing
disk is applied on the frontal edge of the neck of the bottle. The
contents of the bottle -- such as a beverage bottle, for example --
can thus escape, even with the lowest excess pressures within the
bottle, which is obviously not desirable. There exists the dis-
advantage, moreover, that, because of the tolerances or the
contaminants on the frontal surface of the edge of the bottle or on
the sealing, which are caused by manufacturing, a tight contact of
the sealing with the frontal surface of the neck of the bottle is
impossible, particularly in the case of gas bottles.
The task which forms the basis of the invention is that of creating
a sealing closure of the type noted, which is simple in its con-
struction and which, because it is thoroughly independent of the
screwing-on torque, opens reliably with a predetermined excess
pressure.
The task which additionally forms the basis of the invention is
that of describing a process for the simple manufacture of a seal-
ing closure of the type which is stated in claim 1.
The task which forms the basis of the invention is solved by means
of the concept which is stated in the characterizing portion of
claim l.
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WO 92/00892 6 PCT/EP91/01283
The invention is distinguished from the known concepts of
shortening the sealing section or pressing the sealing part as a
whole, by means of an elastic element, against the aperture of the
neck of the bottle. It is the basic concept of the invention,
rather, to create a sealing, a catch unit and an elastic element
solely through the formation of the ring-shaped sealing surface or
the sealing.
One possible expression of this general concept in concrete terms
.... ..
is stated in claim 2. If a bottle is tightly sealed by means of a
sealing closure in accordance with this concept, then it results
that, within the circumference areas of the ring-shaped sealing
surface which do not spring back, the sealing is supported with a
great support force and thereby, in accordance with a type of a
catch unit, the precise position of the sealing part is determined
in relation to the frontal surface of a neck of the bottle. By
this means, however, the force with which the circumference areas
of the sealing abut on the frontal surface of the neck of the
bottle, where the ring-shaped sealing surface rebounds, is also
determined precisely. As the result, the circumference area of the
sealing consequently abuts against the rebounding points of the
ring-shaped sealing surface with a force on the frontal surface of
the neck of the bottle which is determined by its compressibility
and, since the compressibility depends on the shape, the thickness
and the materials composition, and since all of these can be
selected with precision, the sealing pressure on the rebounding
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wo 92/00892 7 PCT/EP91/01283
points of the ring-shaped surface can also be determined precisely
and, consequently, the pressure at which the sealing rises up from
the frontal edge of the neck of the bottle, and consequently allows
the excess pressure to escape.
At that point where the essentially ring-shaped sealing surface of
the sealing part rebounds against at least one point of the circum-
ference, the sealing is, therefore, in the case of sealing closure,
less sharply compressed, and thereby prestressed, so that, under
.. . .. . ..
the desired excess pressures, it rises up, and excess pressure is
allowed to escape. The sealing can thereby be shaped, over the
circumference, in a manner which is complementary to the ring-
shaped sealing surface of the sealing part, and therefore adjusted
to the contour of the sealing surface. In the simplest case, this
means that, in the case of a cap-shaped formation of a sealing
closure in accordance with the invention in the ring-shaped sealing
surface, a depression is provided in an entirely simple manner,
which fills out the material of the sealing, while the support sur-
face of the sealing is positioned, on the frontal surface of the
neck of the bottle, in a radial plane. Such a sealing closure can,
in accordance with the concept of the process claim 8, be produced
in a simple manner, whereby the depressions can be produced, during
the closing process, without any additional expense, whereas only
the corresponding material -- such as foam material, for example --
needs to be selected for the sealing, which likewise represents no
additional expense.
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WO 92/00892 8 PCT/EP91/01283
In accordance with one further construction of the invention, the
sealing can also be a profile sealing, particularly a lip-type
sealing, whereby the profile is shaped over the circumference in a
manner which is complementary to the ring-shaped sealing surface.
In accordance with another expression in concrete terms of the
general concept stated in claim 1, the sealing has a constant
thickness and consists, over its circumference, of materials with
different compressibility. For example, the material of the seal-
ing can have hollow spaces at a number of points, particularly
bubbles, by means of which foam material is formed at these points
by practical means. In all the forms of implementation of the
invention, it is possible to provide recesses on the side of the
sealing which is turned away from the sealing surface, which
ensures a greater compressibility.
The material of the support and sealing part can be of any type,
such as, for example, either plastic or metal. There may be a
screw-type or crown-type sealing closure, or any other sealing
closure which is desired.
The invention will be illustrated in further detail by means of the
diagrams:
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Wo 92/00892 9 pcT/Epsllol283
Figure 1: Depicts an example of implementatïon of
the invention, in a cross-section;
Figure 2: Is a view from above, the top of Figure
l;
Figure 3: Is a lateral view of Figure 1;
Figure 4: Clarifies the process in accordance with
the invention;
Figure 5: Depicts an intermediary step in the pro-
cess in accordance with the invention;
Figure 6: Depicts the end stage of the process;
Figure 7: Depicts another form of implementation of
the basic concept of the invention in a
¦ depiction similar to Figure 1; and:
Figure 8: Depicts a view from above of the sealing
in Figure 7.
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In Figures 1 to 3, a support part (1) and a sealing part (2)
together form a screw cap, for which threads (3) are provided
within the support part (1), by means of which threads the support
part (1) can be screwed onto the bulge-shaped threads (4) of a neck
(5) of a bottle (6) which is only depicted partially. The support
part (1) and the sealing part (2) are deep-drawn or pressed out of
aluminum, as is generally conventional in such types of screw
sealing closures.
... . .
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WO 92/00892 10 PCT/EP91/01283
The sealing part (2) has, in its edge area, a ring-shaped sealing
surface (7), which rebounds at three points (8), and thus has a
greater distance to the frontal surface (9) of the neck of the
bottle (5) than the ring-shaped sealing surface (7).
Between the ring-shaped sealing surface (7) or its rebounding
points (8) and the frontal surface (9) of the neck of the bottle
(5), there is placed a sealing (10), the sealing surface (11) of
which lies in a radial plane, in relation to the neck of the bottle
(5), while its sealing surface (12) positioned on the other side is
constructed in a manner which is complementary to the ring-shaped
sealing surface (7) or its rebounding points (8). The sealing (10)
consists of material which can be compressed in volume, such as,
for example, of foam material.
Figure 1 depicts the sealing closure, which is constructed as a
screw cap, in the screwed-on condition. During the screwing on,
contact forces, which mount very rapidly, and which act in a seal-
ing manner, and simultaneously impede a further screwing on of the
screw cap, so that this has a precisely defined position in relat-
ion to the frontal surface (9) of the neck of the bottle (5?, occur
in the area of the thinner circumference parts of the sealing (10),
in the area of the ring-shaped sealing surface (7).
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WO 92/00892 11 PCT/EP91/01283
During the screwing on, the sealing (10) is compressed, in the area
of the rebounding points (8), by the same distance, but there
result, however, because of the thickness of the sealing (10) which
is greater at that point, lesser support forces on the frontal
surface (9) of the neck of the bottle (5), in a proportion which is
inverse to the thickness. With increasing pressure in the bottle,
the material of the sealing (10) consequently compresses in the
area of the rebounding points (8), so that excess pressure can
escape. The pressure at whlch the excess pressure escapes is
essentially determined through the thickness of the sealing in the
area of the rebounding points (8) and the compressibility in this
area.
Figures 4 to 6 illustrate different process steps in the implement-
ation of the process in accordance with the invention for the manu-
facture of a sealing closure in accordance with the invention.
First, a sealing disk (18), which is smooth, is inserted into a
cap-shaped sealing closure, consisting of a support part (16) and
sealing part (17), which is likewise smooth. Everything is then
placed together, in the direction of an arrow (19), onto the end of
a neck of the bottle (20), as is depicted in Figure 6. After that,
a stamp unit (21) is pressed, in the direction of an arrow (22),
against the sealing part (17). Within the stamp unit (21), there
is provided a depression (23), from which a projection (24) pro-
trudes which, upon the pressing of the stamp unit (21), presses
into the sealing part (17) and produces depressions there, at
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Wo 92/00892 12 PCT/EP91/01283
points which are at a distant from one another, as can be seen from
Figure 6. These depressions represent, in the interior of the
sealing closure cap, projections (25) which, since their surface
expansion is relatively slight, compress the sealing disk (18) very
greatly, so that the projections (25) practically form a catch
unit, which guarantees a precise placement of the sealing closure
cap in relation to the frontal edge of the neck of the bottle (20),
and thereby also the pressing of the sealing disk (18) into the
circumference areas (26). This specific compression into the areas
.. . . .
(26), which can be reproduced by means of the catch units (26),
determines a precisely defined pressure at which excess pressure
can escape.
In the position depicted in Figure 6, a threading (27), as well as
a collar (28), are produced, by means which are not depicted here,
by pressing from the outside against the support part (16), which
serves to make the first opening of the bottle visible.
Figure 7 depicts, in a manner similar to Figure 1, a section
through the upper portion of a neck of the bottle; identical or
corresponding parts are provided with the same reference numbers.
The difference from the form of implementation in accordance with
Figure 1 consists of the fact that a sealing part (26) is con-
structed in a completely developed manner whereas, at the same
time, a sealing (27) has the same cross-section. This sealing, as
is evident from the view from above of the sealing in Figure 8,
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WO 92/00892 13 PCT/EP91/01283
has, however, three areas (28, 29 and 30), which have a compressi-
bility which is slighter -- and, preferably, substantially slighter
-- than that of the central area (31). These areas (28, 29 and 30)
act, therefore, as catch units, and determine the compression of
the central area (31) of the sealing (27) within the area of the
sealing surface. At these points, the material of the sealing can
thus, with a specific excess pressure, rise up from the sealing
support, and consequently allow the excess pressure to escape.
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