WO1993024386A1

WO1993024386A1 - Closure cap

Info

Publication number: WO1993024386A1
Application number: PCT/DE1993/000467
Authority: WO
Inventors: Frank Schellenbach
Original assignee: Schekra Verpackungs Gmbh & Co. Kg
Priority date: 1992-05-27
Filing date: 1993-05-27
Publication date: 1993-12-09
Also published as: EP0642450A1; AU4059793A; DE4217539C2; DE4217539A1

Abstract

A closure cap, in particular for reusable PET bottles (1), has a wall (3) provided with an inner thread (2), a front wall (4) that delimits the cap wall (3) and if required a ring-shaped tamper-evident strip (6) linked to the cap wall (3) and which can be torn at a predetermined breaking point (5). The front wall (4) has a ring-shaped inner seal (7) spaced apart from the cap wall (3), which projects in the direction of the open end and whose outer diameter is tapered in the area (9) of the free end, towards said free end. In order to ensure a gas-tight closure, the inner seal (7) has a swelling (8) in the area of the free end, oriented towards the cap wall (3), and surrounding the area (9) with a tapering outer diameter.

Description

"Cap"

The invention relates to a closure cap, in particular for reusable PET bottles, with a cap wall having an internal thread, an end wall closing the cap wall and possibly an annular guarantee band adjoining the cap wall that can be torn open at a predetermined breaking point, the end wall has an annular inner seal protruding from the open end and spaced apart from the cap wall, the outer diameter of which tapers towards the free end in the region thereof.

Caps of the type in question have been known in practice for some time. Basically, these are screw-on caps for closing bottles, in particular for closing so-called reusable bottles. Bottles of this type are used for filling drinks of any kind, carbonated drinks in particular also being filled into the bottles. Consequently, the closure cap used there must also withstand the gas pressure which arises within the bottle, and must therefore be gas-tight with the bottle or with respect to the bottle.

So-called PET bottles have been on the market for some time now, these being reusable plastic bottles which are offered in particular with a filling volume of 1.5 liters. Because of the considerable tolerances of the bottles in question in the area of the bottle mouth, there are special sealing problems with respect to the closure caps to be used. Consequently, sealing caps with special sealing measures are required here. In addition, the PET bottles in question no longer have flawless mouths and threads, particularly when used repeatedly, especially since they are mostly deformed or damaged by the handling of consumers and bottlers.

A generic cap is already known from practice, in which the mouth of the bottle, i.e. the open free end of the bottle is placed between the cap wall and an inner seal spacing from the cap wall when the closure cap is closed or screwed on. The free end face of the bottle comes into contact with the end wall that closes the cap wall. The inner seal provided there lies in the area of the bottle mouth against the inner wall of the bottle and, due to its inherent elasticity, presses against it, so that a sealing effect is produced.

However, the sealing effect produced in the prior art is not sufficient, especially since a gas pressure building up inside the bottle often leads to leakage between the bottle and the closure cap. The frequency of such leaks is always dependent on the tolerances in the area of the bottle mouth and in the cap itself, so that depending on the occurrence of these tolerances, a more or less strong "reject" or a more or less good "pairing" between the bottle and Cap occurs. In the context of an understandable demand for a bottle filling with almost 100% good parts, such a tolerance-dependent failure of the seal between the closure cap and the bottle is not acceptable in practice.

Now one has already helped with regard to the problem explained above in the prior art in that the caps at least in the region of the end wall, where the end face of the bottle mouth comes to rest, be provided with a special sealing material. For this purpose, a preferably soft plastic is used, which differs from the rest of the material of the cap - aluminum or also plastic - differs. Consequently, this additional sealing measure provides a multi-part closure cap made of different materials, which is no longer justifiable in view of the increasingly required recycling of such parts. In practice, it is not possible to remove an additional seal made of a second material into the sealing cap after use of the sealing cap in order to initiate material-specific recycling. Consequently, with closure caps of the type in question - with different components - there is nothing left but to dispose of them with household waste. However, precisely this should be avoided in the future, so that the solution known from practice for achieving a gas-tight seal, in particular of reusable PET bottles, cannot be implemented or can only be implemented in extreme emergency.

The invention is therefore based on the object of specifying a closure cap, in particular for reusable PET bottles, with which bottles of the type in question can be effectively closed or sealed even under considerable pressure inside the bottle, and which, with a simple construction, have no more suitable for recycling.

The closure cap according to the invention is characterized by the features of the independent claims 1 and 2. According to this, the closure cap according to the invention is characterized in the context of a first alternative in that the inner seal has a bead directed towards the cap wall and formed in the area of the free end, and in that the bead comprises the area which tapers in outside diameter.

According to the invention, it has been recognized here that for the gas-tight closure of a bottle by means of the screw-type A special design of the inner seal is required. This particular embodiment is characterized in that the inner seal in the area of the free end has a bead directed towards the cap wall, which, when the cap is screwed on, presses against the inner wall of the bottle in the area of the bottle mouth. Due to the formation of the bulge in the area of the free end and due to the integration of the region tapering in the outer diameter in the bulge, the inner seal presses very strongly against the inner wall of the bottle when the closure cap is screwed on and effectively seals between the inner seal and the inner wall of the bottle from. A gas pressure building up inside the bottle is used in a very particularly advantageous manner for pressing the inner seal against the inside wall of the bottle, the bulge formed at the free end of the inside seal being pressed against the inside wall of the bottle with enormous pressure due to the considerable distance from the end wall. Due to the relatively wide engagement of the inner seal or the bead provided at the free end, it is not possible for the bead to slide off at the bottle mouth, rather a certain sliding of the bead along the inside of the bottle is possible without the sealing Losing effect.

As an alternative to the teaching according to the invention discussed above, the sealing cap according to the invention can also be characterized by the features of patent claim 2. According to this, the closure cap according to the invention is designed in such a way that the end wall in the region between the cap wall and the inner seal has a first annular wedge seal which projects from the end wall and is at least slightly inclined towards the inner seal. In the context of this alternative according to the invention it has been recognized that a sufficient seal between the cap and the bottle to be closed can be realized in that between the inner seal and the Cap wall is formed a seal referred to as a wedge seal due to its wedge-shaped configuration. This seal, too, is of circular design and, due to its inclination towards the inner seal, is bent further towards the inner seal when screwing onto a bottle, so that the wedge seal is fixed in the area of the bottle mouth due to its inherent elasticity and the tension caused by the screwing on on the bottle.

With regard to a particularly effective seal between the closure cap and the bottle, it is advantageous if, in addition to the provision of the previously discussed wedge seal, the inner seal has a bead directed towards the cap wall and formed in the area of the free end, and if this bead comprises the area which tapers in the outer diameter. In other words, the features previously presented as alternative solutions are combined here in a very particularly advantageous manner in order to significantly and effectively improve the sealing effect, in particular in view of a very high gas pressure inside the bottle.

With regard to the design of the inner seal, it is a further advantage if it runs on the side facing away from the cap wall approximately in a straight line up to the bead. This means that the inner wall of the inner seal forms an approximately circular inner surface. On the side facing the cap wall, the inner seal merges into the bead in an approximately arc shape, ie the side of the inner seal facing the cap wall extends in the direction of the cap wall. From there, the inner seal tapers again approximately rectilinearly in the outer diameter, as a result of which a wedge surface runs from the lower end of the inner seal to the outermost region of the bead, by means of which the inner seal or the bead of the inner seal into the bottle mouth can be introduced. Because of this wedge-shaped configuration, the inner seal is pressed inward approximately by the amount of the bead protruding and, because of the material-specific elasticity, therefore exerts considerable pressure on the inner wall of the bottle in the mouth area due to the tension achieved in the process. The bead is preferably dimensioned and extends into the cap wall in such a way that the inner seal or bead in the screwed-on state - corresponding to the tolerances on the one hand of the closure cap and on the other hand the bottle mouth - with a predetermined contact pressure against the inside wall of the bottle in the area the bottle mouth presses.

The previously mentioned first wedge seal is positioned and dimensioned in a particularly advantageous manner in such a way that, when the closure cap is screwed on, it can be pretensioned against the radius of the bottle neck, i. at the transition into the bottle mouth. In other words, when the cap is screwed on, the first wedge seal is bent towards the end wall and, due to its inherent elasticity and the resulting tension when pressed, presses against the radius of the bottle neck or exactly at the transition into the bottle mouth, i.e. to the edge between the end face of the bottle mouth and the inside wall of the bottle. When pressure builds up from the inside, the wedge seal is pressed more strongly against the bottle radius, so that the sealing effect is increased again due to the internal pressure. The same applies to the inner seal mentioned in detail above, which also exceeds the contact pressure achieved by the material-specific tension due to the pressure building up inside the bottle, i.e. reinforced, pressed against the inside wall of the bottle.

The first wedge seal can have a concretely different shape, for example towards the free end with an essentially general flat surfaces taper to a point. Likewise, the two-sided surfaces of the first wedge seal could be made concave or convex. Rounding the free end of the first wedge seal is also possible.

To further increase the sealing effect of the closure cap according to the invention, it is of particular advantage if in the area between the cap wall and the inner seal, preferably in the transition between the cap wall and the end wall, i.e. approximately at the angle formed between the cap wall and the end wall, a second annular wedge seal protruding from the end wall or from the cap wall and at least slightly inclined toward the inner seal is provided. This second wedge seal can be positioned and dimensioned in such a way that, when screwed on, it serves for the pretensioned system on the end face of the bottle mouth. Accordingly, the second wedge seal, like the first wedge seal, is bent toward the end wall when the closure cap is screwed on, as a result of which, due to the inherent elasticity of the second wedge seal, a considerable contact pressure is exerted on the bottle, more precisely said on the end face of the bottle mouth. The second wedge seal can also taper to the free end with essentially flat surfaces, whereby these two-sided surfaces of the second wedge seal can also be concave or convex. The statements made for the first wedge seal also apply to the second wedge seal, so that further explanations are unnecessary.

With a view to improving the sealing effect of the closure cap according to the invention, it is finally possible for the cap wall, preferably in the upper region, ie in the region shortly before the transition to the end wall, to have an approximately radial or inwardly projecting annular seal for abutment against the bottle outer wall having. This can be an im Act in the sense of a cord seal or a sealing ring, this preferably being an integral part of the closure cap. In the sense of a sealing bead, this seal could be rounded inwards and so dimensioned that it bears against the outer wall of the bottle under tension when screwed on.

The above statements regarding different sealing measures between the closure cap and bottle make it clear that a combination of the above sealing measures or seals leads to a kind of multi-barrier system with regard to the sealing of the bottle. Except for the seal assigned to the cap wall, all seals are designed so that they have an increased sealing effect with increasing internal pressure, since they increase more, i.e., due to the increasing internal pressure. with higher contact pressure, apply to the bottle wall or face of the bottle.

With regard to a secure and recognizable closure of the bottle, it is now of particular advantage if a guarantee band, which is already known from the prior art, is provided. This guarantee band adjoins the cap wall on the side facing away from the end wall and has a first predetermined breaking point. However, such a configuration of the guarantee band is problematic in that when the bottle is opened, ie when the closure cap is unscrewed, the guarantee band is first broken open and torn from the closure cap by numerous users as a whole. After use, ie after the bottle has been emptied, this entire torn guarantee band often moves into the interior of the bottle, from which it is difficult to remove due to its curved configuration. During the cleaning process of the bottle, the guarantee bands that have entered the inside of the bottle cannot be rinsed out. So-called bottle inspection machines do not recognize these tapes, as a result of which it is not uncommon for such old - used - guarantee tapes to get into a beverage that is refilled into the reusable bottle. Complaints are preprogrammed here.

It is consequently very particularly advantageous to equip the guarantee band in question with a second predetermined breaking point in order to avoid the aforementioned problems. This second predetermined breaking point could be arranged in such a way that it lies approximately opposite the first predetermined breaking point, so that the tamper-evident band, after tearing open the first predetermined breaking point, can be divided into two halves of approximately the same length due to a tearing open of the second predetermined breaking point. As a result, the guarantee tape cannot be torn off in one piece, but only in two parts, namely in two short pieces. These two short parts resulting from the entire guarantee band can be easily rinsed out of the bottle through the relatively narrow bottle mouth, so that the aforementioned problem is solved.

With regard to simple manufacture, it is particularly advantageous if the closure cap is made in one piece. Plastic, in particular polyethylene, is particularly suitable for this purpose, especially since this plastic can easily be fed to a recycling process. Finally, in the case of the closure cap according to the invention, it is essential that it can be produced exclusively from one and the same material, so that no material combinations with regard to the end wall, cap wall and seals provided in the interior of the closure cap are required.

There are various possibilities for advantageously designing and developing the teaching of the present invention. For this purpose, on the one hand, to patent claims 1 and 2 subordinate claims, on the other hand to refer to the following explanation of an exemplary embodiment of the invention with reference to the drawing. In conjunction with the explanation of the preferred exemplary embodiment of the invention with reference to the drawing, preferred embodiments and further developments of the teaching are also explained in general. In the drawing shows

1 shows a sectional illustration, enlarged, of an embodiment of a closure cap according to the invention,

FIG. 2 shows the object from FIG. 1, partially, in the state screwed onto a bottle and

3 shows the object from FIG. 1 in section along the line A-A.

1 to 3 together show an embodiment of a closure cap according to the invention for reusable PET bottles 1, with a cap wall 3 having an internal thread 2, an end wall 4 which closes the cap wall 3 and an adjoining the cap wall 3 on one The predetermined breaking point 5 of the tear-open annular guarantee band 6, the end wall 4 having an annular inner seal 7 protruding from the open end and spaced apart from the cap wall 3, the outer diameter of which tapers towards this in the area of the free end.

According to the invention, the inner seal 7 has a bead 8 directed towards the cap wall 3 and formed in the region of the free end. The bead 8 comprises the area 9 which tapers in the outer diameter. The figures further show that the end wall 4 in the region between the cap wall 3 and the inner seal 7 has a first annular wedge seal 10 projecting from the end wall 4 and inclined towards the inner seal 7.

The inner seal 7 runs on the side facing away from the cap wall 3 in a roughly straight line up to the bead 8. On the side facing the cap wall 3, the inner seal 7 runs approximately in an arc shape up to the bead 8, thus going into the bead 8 over, and from there tapers again approximately rectilinearly in the outer diameter. The bead 8 is dimensioned in this art der¬ or erεtreckt is such to cap wall 3 to the fact that the inner seal 7 and 8 in the bead aufge¬ screwed-on state with a predetermined pressing force against the ^{'Flascheninnenwandung} 11 in the region of the bottle mouth 12 presses.

2 shows particularly clearly that the first wedge seal 10 is positioned and dimensioned in such a way that, in the screwed-on state, it serves for the pretensioned contact on the radius or on the inner edge 13 of the bottle neck 14 or at the transition into the bottle mouth 12. The first wedge seal 10 tapers towards the free end with essentially flat surfaces.

1 and 2 clearly show that in the area between cap wall 3 and inner seal 7 in the transition between cap wall 3 and end wall 4 there is a second circular ring which projects from the end wall 4 or from the cap wall 3 and slopes towards the inner seal 7 Wedge seal 15 is provided. The second wedge seal 15 is positioned and dimensioned as shown in FIG. 2 in such a way that, when screwed on, it is used for prestressed contact with the end face 16 of the bottle mouth 12. Furthermore, the second is Wedge seal 15 tapered towards the free end with flat surfaces.

1 and 2 further show that the cap wall 3 in the upper region, i.e. in the area shortly before the transition to the end wall 4, an approximately radially or inwardly protruding circular ring-shaped seal 17 for contacting the outer wall wall 18. This seal 17 is in the sense of a sealing bead towards the inside, i.e. to the bottle outer wall 18, rounded. The seal 17 is dimensioned according to the illustration in FIG. 2 such that it bears against the outer wall 18 of the bottle under tension in the screwed-on state.

Finally, FIGS. 1 and 2 show together that the guarantee band 6 has a second predetermined breaking point 19. The second predetermined breaking point 19 lies opposite the first predetermined breaking point 5, so that the tamper-evident band 6 can be divided into two halves 20, 21 of approximately the same length when the first predetermined breaking point 5 is torn open due to the second predetermined breaking point 19 being torn open.

Finally, it should be emphasized that the closure cap is made in one piece overall and consists of plastic, namely of polyethylene.

Finally, it should be emphasized that the exemplary embodiment discussed above is only used for a better understanding of the teaching according to the invention, but does not restrict it to the exemplary embodiment.

Claims

1. Cap, in particular for reusable PET bottles (1), with a cap wall (3) having an internal thread (2), a front wall (4) closing the cap wall (3) and, if applicable, a cap wall (3) subsequent, at a predetermined breaking point (5) tearable circular ring-shaped guarantee band (6), whereby the end wall (4) has an annular inner seal (7) protruding towards the open end and spaced apart from the cap wall (3), the outer diameter of which is in the Area (9) of the free end tapers towards it, characterized in that the inner seal (7) has a bead (8) directed towards the cap wall (3) and formed in the area of the free end and that the bead (8 ) includes the area (9) tapering in the outer diameter.

2. Cap, in particular for reusable PET bottles (1), with a cap wall (3) which has an internal thread (2), a front wall (4) which closes the cap wall (3) and, if appropriate, a cap wall (3) following, at a predetermined breaking point (5) which can be torn open an annular guarantee band (6), whereby the end wall (4) has an annular inner seal (7) protruding towards the open end and spaced apart from the cap wall (3), the outer diameter of which can be seen in the Be¬ area (9) of the free end tapered towards this, characterized in that the end wall (4) in the area between the cap wall (3) and the inner seal (7) protrudes from the end wall (4), at least slightly to the inner seal (7) has inclined first annular wedge seal (10).

3. A closure cap according to claim 2, characterized in that the inner seal (7) has a bead (8) which is directed towards the cap wall (3) and is formed in the region of the free end and that the bead (8) tapering the outer diameter εich Area (9) includes.

4. Cap according to claim 1 or 3, characterized gekenn¬ characterized in that the inner seal (7) on the side facing away from the cap wall (3) runs approximately rectilinearly towards the bead (8) and on the side facing the cap wall (3) Side merges into the bulge (8) in an approximately arc shape and tapers from there again in a roughly straight line in the outer diameter.

5. A sealing cap according to claim 3 or 4, characterized in that the bead (8) is dimensioned in such a manner or extends to the cap wall (3) that the inner seal (7) or bead (8) in the the screwed-on state with the specified contact pressure presses against the inside wall of the bottle (11) in the area of the bottle mouth (12).

6.Capping cap according to one of claims 2 to 5, characterized in that the first wedge seal (10) is positioned and dimensioned such that εie in the screwed-on state to the pretensioned system on the radius of the bottle neck (14), i.e. at the transition into the bottle mouth (12).

7. A closure cap according to claim 6, characterized in that the first wedge seal (10) tapers towards the free end with essentially flat surfaces.

8. Cap according to one of claims 1 biε 7, characterized in that in the region between the cap wall (3) and the inner seal (7), preferably in the transition between the cap wall fertilizer (3) and end wall (4), a second circular wedge gasket (15) protruding from the end wall (4) or from the cap wall (3) and at least slightly inclined towards the inner seal (7).

9. A closure cap according to claim 8, characterized in that the second wedge seal (15) is positioned and dimen¬ εioniert iεt that it serves in the screwed state for pre-tensioned contact on the end face (16) of the bottle mouth (12).

10. Cap according to claim 8 or 9, characterized in that the second wedge seal (15) tapers toward the free end with essentially flat surfaces.

11. Cap according to one of claims 1 to 10, characterized in that the cap wall (3) in the upper region, i.e. in the area shortly before the transition to the end wall (4) has an approximately radially or inwardly projecting annular seal (17) for abutment against the bottle outer wall (18).

12. A closure cap according to claim 11, characterized in that the seal (17) is rounded inwardly in the sense of a seal bead.

13. Cap according to claim 11 or 12, characterized in that the seal (17) is dimensioned in such a way that it bears against the outer wall of the bottle (18) under pretension in the screwed-on state.

14. Cap according to one of claims 1 to 13, characterized in that daε guarantee tape (6) has a second Sollbruch¬ point (19).

15. closure cap according to claim 14, characterized in that the second predetermined breaking point (19) of the first predetermined breaking point (5) is approximately opposite, so that daε guarantee tape (6) when torn - after tearing the first predetermined breaking point (5) - due to a tearing open second predetermined breaking point (19) can be divided into two halves (20, 21) of approximately the same length.

16. Cap according to one of claims 1 to 15, characterized in that the cap is made in one piece.

17. A closure cap according to one of claims 1 to 16, characterized in that the closure cap is made of synthetic material.

18. A closure cap according to claim 17, characterized in that the closure cap is made of polyethylene (PE).