EP1105318B1 - Sealing cap - Google Patents

Abstract

The invention relates to a sealing cap (1) which has a base (2) and a skirt (3) and comprises an internal seal (4). Said internal seal is provided with ventilation recesses (11) which cancel out the sealing effect when the cap base (2) is moved axially upward. The sealing cap (1) further comprises a first stop end (7) and a second stop end (8). When the cap is unscrewed the second stop end (8) is the first to engage the opening of the container, so that a weak zone (9) in the area of the cap wall (3) is prestressed to a defined value. On the basis of the definable prestress of the weak zone (9), ventilation can be achieved at a precisely defined positive pressure.

Description

The invention relates to a closure cap with the features of the preamble of claim 1 (see for example the Document WO-A-95/21095).

Caps made of plastic material are in one Variety for closing containers, for example Beverage bottles used.

Especially with carbonated drinks, but also with Fruit juices, the problem is that the internal pressure in the Containers can rise over time (due to temperature increase or fermentation). Because caps usually should seal as well as possible to avoid leakage, there is a risk that the container due to an elevated Internal pressure bursts. Especially with glass bottles jumping glass fragments is a potential danger.

Various types have been used to solve this problem suggested by caps.

From EP-A-597 867 it is known, for example, a closure cap to be provided with a sealing insert and at the same time to define the screw-on position of the sealing cap. If the internal pressure is increased, the sealing washer should be compressed and act as a pressure relief valve.

EP-A-464 384 discloses a self-venting bottle cap known, due to weaknesses in the top plate the sealing effect is canceled with increased internal pressure shall be.

DE-A-196 13 830 describes a self-venting closure known in which the cap base is weakened. The Weakening leads to the fact that the The base of the cap is arched outwards (so-called doming) and that it is formed in one piece with the cap base Inner seal is relieved of pressure.

However, all of these known solutions have certain disadvantages on. The degree of compression of an inserted sealing washer is difficult to control. In addition, the Pressing the sealing washer over the entire circumference of the container mouth homogeneous, so that the precise control of the venting process is difficult.

With sealing caps with weaknesses in the top plate there is a problem that due to an inner seal of the doming can be relieved of pressure, but that seals, which on the upper edge of the mouth and especially on the outside Seal the container mouth so that it is not relieved of pressure.

It is an object of the invention to overcome the disadvantages of the known to avoid, in particular a closure cap create which with optimal tightness under normal conditions reliable and precisely controllable venting with increased internal pressure in the closed by the cap Container allows. The cap should be simple and be economical to produce and with conventional screwing devices be screwable.

According to the invention, these tasks are performed with a sealing cap with the features of the characterizing part of claim 1 solved.

The cap essentially consists of a cap base and a cap wall. There is a circumferential one on the cap bottom Internal seal provided. The seal is with a Seal line, which against the inside of the container mouth can be pressed and achieves a sealing effect.

The cap can also be on the inside of the cap wall arranged retaining elements, for example one Screw thread, are held on the container mouth.

The closure cap has a first stop, which arises approximately from the bottom of the cap.

According to the invention is axially between the retaining elements and the first stop a second stop to limit the screwing movement of the cap is arranged. The second stop can start with, for example Engage threads on the container mouth and so the Limit unscrewing movement. The second stop is advantageous formed as a circumferential ring, the stop plane runs approximately perpendicular to the axis of the closure cap.

The cap wall is also with a deformable wall section Mistake. The deformable wall section is between arranged the first and the second stop. The Deformability can be achieved by weakening the wall thickness in the Area of the wall section can be achieved, for example through a recess on the inside of the cap wall.

The inventors of the present invention have found that a weakening of the closure cap in the area of the Cap wall compared to known weaknesses in the cap base has surprising advantages. An increased internal pressure in the container closed by the cap not primarily a curvature of the cap base, but an axial displacement of the cap base. The So movement is essentially linear. This means that any seals on the outside or on the front the container mouth due to the axial translation movement of the cap bottom also out of sealing engagement devices. Of course, there can still be a specific one Curvature occur.

So that the closure cap is vented at the right time, the axial distance between the first and the second stop on the one hand and the depth of penetration of the sealing line on the other hand are selected such that the sealing line disengages from the inside of the container mouth at a predetermined internal pressure. This minimum pressure varies depending on the contents in the container. In the case of fruit juices it is around 2 bar, in the case of beverages with a low CO ₂ content it is 5 bar and in the case of a content with 4 vol.% CO _{2 it is} above 8 bar. The degree of deformability of the wall section is also selected accordingly.

The first stop engages when screwed on the top of the tank mouth before the second stop engages with the start of the thread.

In between is the first stop and the deformable wall area deformed due to the unscrewing movement.

The penetration depth of the sealing line denotes the axial one Distance of the sealing line from the first stop in deformed Condition or distance of the sealing line from the top the container mouth.

Through the targeted choice of the distance between the stops and the deformability of the wall section becomes the deformable Wall section when screwing on the lock in the Type of spring biased to a predetermined value. By a suitable choice of the penetration depth of the sealing line, the Predeterminable time of venting. If the inside pressure is so large that the cap bottom turns against the spring force the depth of penetration is shifted, the closure vents.

The deformability is set for normal conditions, i.e. for temperatures in the range of 15 - 35 ° C. If the outside temperature If these values are exceeded, the deformability larger (softening of the plastic material). The venting function is therefore favored at a higher temperature.

The two stops serve for precisely defined pretensioning the weakening zone in the cap wall. One can do exactly that predefined ventilation pressure can be set.

The inner seal also advantageously points to the Ventilation cutouts on the side facing the cap apron. The ventilation cutouts are below the sealing line arranged. The inner seal is advantageous as a so-called Olive seal trained. This means that the sealing line a maximum outer diameter of the inner seal defined and spaced from the inside of the cap base is arranged. Such olive seals have the advantage in Seal inside the container mouth, where normally one to find a precisely defined sealing surface without damage is. The disadvantage of such olive seals is that they already seal due to the preload when the Sealing cap is not in the attached position, but axially slightly above the sealing position. thanks to the Ventilation recesses, which are advantageous immediately below start the sealing line, the sealing effect is canceled, as soon as the sealing line outside the container mouth lies. An extension of the sealing effect due to a shift the sealing line over which is tapered down This prevents a tapering inner seal.

The cap can also with a circumferential Be sealing bead provided against the outside of the Container mouth can be pressed. The sealing bead is axial arranged between the first and second stop.

The closure cap is also advantageous with hold-open elements Mistake. Such hold-open elements can, for example above the sealing line on the cap wall facing surface of the inner seal may be provided. The Keep-open elements prevent the sealing line from shifting. If there is still doming of the internal pressure If the bottom of the cap comes, the hold-open elements are supported on the container mouth, so the location of the inner seal with respect to the container mouth essentially only is changed by translation. Can keep open of course on the other sealing elements, in particular on the second stop acting as a seal or on the optional against the outside of the container annular bead.

The invention is described below in exemplary embodiments and explained in more detail using the drawings:

Figur 1

einen Querschnitt durch eine erfindungsgemässe Verschlusskappe,

Figur 2

einen vergrösserten Ausschnitt der Dichtpartie einer Verschlusskappe auf einer Behältermündung,

Figur 3

eine vergrösserte Darstellung der Dichtpartie eines Verschlusses auf einem Behälter mit erhöhtem Innendruck und

Figur 4

eine schematische Darstellung einer Untenansicht einer Verschlusskappe.

Show it:

Figure 1

3 shows a cross section through a closure cap according to the invention,

Figure 2

an enlarged section of the sealing part of a closure cap on a container mouth,

Figure 3

an enlarged view of the sealing part of a closure on a container with increased internal pressure and

Figure 4

is a schematic representation of a bottom view of a closure cap.

Figure 1 shows a cap 1, which essentially consists of a cap base 2 and a cap wall 3. The Cap wall 3 is provided with a screw thread 6, with which the cap 1 on a container mouth 20th can be screwed on.

On the inside of the cap base 2 there is an inner seal 4 arranged in the form of a circumferential sealing lip. The Inner seal 4 is designed as a so-called olive seal. The inner seal 4 has a sealing line 5, which can be pressed against the inside of a container mouth. The sealing line 5 is at a distance from the inside of the cap base 2 arranged and defines the maximum outer diameter the surface 10 of the cap apron 3 facing the Inner seal 4.

The inner seal 4 is below the sealing line 5 with ventilation cutouts 11 provided which on the surface 10 are arranged.

There is a first stop on the inside of the cap base 2 8 provided. The first stop 8 is a circumferential bead trained who also has a sealing function.

A second stop 7 is located above the end of the thread 6 on the inside of the cap wall 3 above the thread 6 arranged. The stop 7 has a stop plane that runs approximately perpendicular to the axis of the closure cap. The Stops 7, 8 are predeterminable in the axial direction Distance d spaced.

Is between the first stop 8 and the second stop 7 the cap wall 3 is provided with a deformable wall area 9.

On the surface 10 of the inner seal 4 are also Open hold elements 13 are arranged, which ensure that the sealing line 5 of the inner seal 4 does not shift, i.e. that the inner seal 4 only in the area of the sealing line 5 can be sealed against the inside of the container mouth.

The outside of the cap apron 3 is also with a Corrugation or provided with ribs 14, which the cap wall 3 below the weakening zone 9 sufficient strength and give good grip properties.

The cap 1 can also with a guarantee tape 15 and be provided with vertical ventilation slats 16, which interrupt the thread 6. Such guarantee tapes and Vent slots are known to those skilled in the art.

In Figure 2, the sealing part of the closure cap is according to Figure 1 is shown enlarged. If the cap 1 is screwed onto a container mouth 20, comes first the first stop 8 with the end face 23 of the container mouth 20 engaged. By further screwing on the Cap wall 3 in the region of the deformable wall section 9 deformed axially until the second stop 7 with the Thread start 22 of the container mouth 20 engages. In the fully applied state is the deformable one Wall area 9 biased to a precisely predetermined value.

At the same time, a circumferential sealing bead 12 seals against the Outside 24 of the container mouth 20. On the inside 21 the container mouth 20 is the inner seal 4 with the Sealing line 5 sealing. The sealing line 5 has a through relative position to the second stop 7 predetermined penetration depth t in the tank mouth.

As soon as in the container closed with the cap 1 the internal pressure increases, the cap base 2 becomes axial Direction A shifted up (see Figure 3). The axial Displacement of the cap base 2 is due to the deformable Wall section 9 favors. The second stop 7 remains thereby engaging with the thread beginning 22 of the container mouth 20. The first stop 8 is from the end face 23 of the Container mouth 20 lifted and the inner seal 4 slides along the inside 21 of the container mouth 20 in the direction of the arrow A upwards so that the sealing line 5 is disengaged with the inside 21. An increased internal pressure can therefore compensated for by the ventilation recesses 11 become. Between the second stop 7 and the beginning of the thread 22 is due to the thread pitch only on a short Circumferential section a sealing contact. The reduction of the internal pressure is also through the ventilation slots shown in Figure 1 16 favors.

The axial displacement of the cap base 2 also the pressed against the outside 24 of the container mouth 20 Bead 12 relieved of pressure, so that ventilation is possible.

The ventilation cutouts 11 are of particular advantage, because the inner seal 4 is preloaded into the container mouth is introduced and the sealing line 5 deep in the Container mouth is arranged. Because of the ventilation cutouts 11 ventilation takes place as soon as the sealing line 5 out of engagement with the inner surface 21 of the container mouth occurs. Without ventilation cutouts 11 would Surface 10 of the inner seal 4 due to the bias also below the sealing line 5 during the axial displacement still in sealing engagement with the inside 21 of the Container mouth 20 remain.

Set the hold-open element 13 or the hold-open elements 13 a straight displacement of the cap bottom 2 safely and prevent the inner seal 4 from tilting, i.e. over the lying above the sealing line 5 Surface rolls.

In Figure 4, the cap 1 is schematically in the Shown bottom view. Threads, stops and the outside Sealing bead 12 are omitted for simplification. The ventilation cutouts 11 and the hold-open elements 13 are arranged regularly over the circumference of the inner seal 4.

The essence of the invention is the cap bottom 2 without Form weaknesses so that doming of the cap base, i.e. an outward curvature is made difficult or reduced. Instead, a deformable wall section 9 is in the area the cap wall 3 provided. This weakening in the area of Cap wall 3 allows axial movement of the cap base with increased internal pressure. The representation shown in Figure 3 is exaggerated to illustrate the gas release process executed. In reality, the cap bottom lifts up increased internal pressure only by a small amount. Once the Internal pressure decreases again, the cap bottom 2 lowers again and the sealing cap 1 seals again. It has shown that with such arrangements, the internal pressure in the Containers on one sufficient for several weeks can be kept low. There are a lot of them of successive venting processes.

Essential for the degree of preload of the weakening zone 9 is the distance d between the first stop 7 and the second stop 8 compared to the axial distance d between the upper edge of the thread start 22 and the end face 23 of the container mouth 20. The distance between the stops 7, 8 is 1.3 to 1.5 mm in the exemplary embodiment. The Distance between the top of the thread start 22 and Front side 23 of the container mouth 20 is 1.7 mm. The depth of penetration t of the sealing line 5 is depending on the content of the Container 0.8 to 1.0 mm.

The venting recesses 11 are at a distance of 0.2 to 0.3 mm below the sealing line 5 on the surface 10 of the Inner seal 4 arranged. The ventilation cutouts 11 extend towards the lower end of the inner seal 4 at least over that part of the surface 10 of the inner seal 4, which when screwing or unscrewing the cap 1 in engagement with the inside 21 of the The container mouth can stand.

Claims (8)

1. A closure cap (1) with a cap base (1) and with a cap wall (3)
   with a circumferential inner seal (4) rising from the cap base (2), with a sealing line (5) which with a screwed-on closure cap can be brought into engagement with the inner side (21) of a container opening (20),
   and with retaining elements (6) arranged on the cap wall (3), for retaining the closure cap (1) on the container opening (20),
   whereby the closure cap (1) comprises a first abutment (8) which rises from the cap base (2), and whereby
   the closure cap (1) comprises a second abutment (7) axially arranged between the retaining elements (6) and the first abutment (8), for limiting the screwing-on movement,
   characterized in that the cap wall (3) is provided with a deformable wall section (9) which is axially arranged between the first abutment (8) and the second abutment (7), wherein the distance (d) between the first abutment (8) and the second abutment (7), the penetration depth (t) of the sealing line (5) and the degree of deformability of the wall section are selected in a manner such that the sealing line (5) at a predeterminable inner pressure can be brought out of sealing engagement with the inner side (2) of the container opening.
2. A closure cap according to claim 1, characterised in that the first abutment (8) and the second abutment (7) are arranged in a manner such that the second abutment (7) can be brought into engagement with the beginning (22) of the thread of the container opening (20) after the first abutment (8) can be brought into engagement with the end-face side (23) of the container opening (20).
3. A closure cap according to one of the claims 1 or 2, characterised in that the inner seal (4) on its surface (10) facing the cap wall comprises at least one venting relief (11) arranged below the sealing line (5).
4. A closure cap according to claim 3, characterised in that the venting relief (11) begins directly below the sealing line (5) and extends towards the end of the inner seal (4).
5. A closure cap according to one of the claims 1 to 4, characterised in that the closure cap comprises a circumferential sealing bulge (12) which is axially arranged between the first abutment (7) and the second abutment (8) and which can be pressed against the outer side (24) of the container opening (20).
6. A closure cap according to one of the claims 1 to 5, characterised in that the surface (10) of the inner seal (4), which faces the cap skirt (3), comprises at least one retaining-open element (13) which is axially arranged above the sealing line (5).
7. A closure cap according to one of the claims 1 to 6, characterised in that the deformable wall section (9) is formed by a weakening of the wall thickness, preferably by a deepening on the inner side of the cap wall (3).
8. A packaging with a closure cap according to one of the claims 1 to 7 with a container with a container opening with a thread, wherein the container opening comprises an end-face side (23) with which the first abutment (8) can be brought into engagement, wherein the thread comprises a start (22) with which the second abutment (7) of the closure cap can be brought into engagement, and wherein the axial distance (d') between the end-face side (23) and the beginning (22) of the thread is larger than the axial distance (d) between the first abutment (8) and the second abutment (7).

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