EP0529383B2 - Plastic screw cap for pressurized bottles - Google Patents

Description

The present invention relates to a plastic screw closure for bottles, especially for under Pressurized beverage bottles consisting of a basic cylindrical jacket with an internal thread and an essentially circular disk Head plate, on the inside of which is a thin, annular sealing strip is integrally formed and at their transition to the cylindrical shell on the inside a bead for pressing the sealing strip to the upper, outer edge of the bottle neck is provided, the bead one concentric to the closure axis, at least has partially cylindrical inner wall, the Diameter is slightly larger than the outside diameter of the upper edge of the bottle neck.

Such a closure is from EP-A-0 114 127 known. In the known closure both on the inside and on the outside two sealing strips running at an angle to the closure axis provided a V-shaped opening form into which the bottle neck edge when screwing of the closure engages. Through the V-shaped Tilt the two sealing strips these are screwed onto the bottle neck essentially pushed up vertically and folded away, while sticking to the bottle neck more or less dense and on both sides of the The sealing strip provided for the free spaces become. The bottom of the V-shaped opening of the both sealing strips face the surface the head plate a little, so that the further screwing and compressing the weather strips by engaging this reason with the top of the bottle neck is limited.

A closure is known from US-A4,623,070, which also has the characteristics of the generic term of Claim 1 has. With this runs the Sealing strips essentially along one Axis of the closure of the conical surface. The edge of the bottle neck captures this sealing strip along the conical surface from below and presses it also essentially up in one for that provided space in the headstock.

Furthermore, a similar closure from EP-A1-293.901 known. With this closure the Bead has a substantially triangular cross section with a accordingly conical to the headstock tapering inner wall, parallel to it a conical sealing strip that extends when screwed on of the closure on a bottle neck on the top outer edge of the bottle neck hangs up and from the conical inner surface the sealing bead is pressed. Here lies the Approach of the conical sealing strip on the head plate relatively far in the radial direction and aligned essentially with the cylindrical inner edge of the Bottle neck. Only the outer end of the conical Sealing strip is between the conical inner surface of the bead and that rounded in this area Transition from the face of the Bottle neck clamped to its cylindrical outside.

Carbonated drinks are made in bottles depending on temperature and transport conditions a significant overpressure of a few bars. The headstock made of elastic plastic material Screw cap bulges above and thus also lifts the shoulder of the sealing strip more or less, so that too free end at least partially from the pinched Area can be pulled out. A poet Completion is no longer guaranteed in all cases. The tightness of the known closure also affected by the fact that the screwed Closure of the sealing strips on the Face of the bottle neck rests, being over This sealing strip still has a lot of freedom is available. With overpressure the relatively thin and easily movable sealing strip, which is only on his outer end between bottle neck and bead is pinched by the pressurized gas or lift the liquid off the bottle neck and pressed towards this free space, whereby also the free end from the pinched Area can slip out.

There are also others in the prior art Known plastic closures, which instead of one one-piece molded sealing strip separate sealing washer or a separate Provide the sealing ring, which before screwing the Closure is inserted into this. Such a closure design is more complex and more expensive because of the wide distribution of such bottles and correspondingly high turnover figures already low Penny amounts considerable as a cost difference noticeable.

The known closures all have the Disadvantage that the sealing strips, if they exist are, due to their more or less conical Essentially during the procedure with the bottle neck just pushed up and pressed together become.

This does not always ensure adequate Tightness if the closure is not sufficient Force screwed onto the bottle neck becomes. While screwing on with a sufficient Force after filling the bottles with secure suitable machines relatively well this is not always guaranteed for the consumer, especially since it often bothers the consumer when he open such a bottle with considerable effort must, in particular, less powerful people sometimes only by using additional Aids such as pliers and the like is possible. In this respect, there is still a need for a closure, the tightness even then is guaranteed if the closure of only Hand with one compared to mechanical locking low force is screwed on. Therefore lies the object of the present invention is a plastic screw cap with the input to create the characteristics mentioned, its tightness even with considerable overpressure in a bottle is guaranteed even if the closure only screwed on by hand with normal effort is.

This object is achieved in that the sealing strip also essentially cylindrical is, the outer diameter of the Sealing strip approximately equal to the outside diameter of the bottle neck rim, and that on both sides the sealing strip has a circumferential groove in the Head plate is provided such that the weather strip when screwing on between bead and bottle neck not only in Area of the rounded transition between the annular face and the outer cylinder surface is pinched, but through the bead further into the Annular gap between the outer cylindrical surface of the bottle neck and the cylindrical inner wall of the bead is drawn.

This is the sealing strip on the head plate assuming that he (with the closure attached) in the Near the outside of the cylindrical bottle neck rim and also runs close to the bead.

The combination of Characteristics, i.e. especially by essentially the cylindrical Formation of the sealing strip, the outer Diameter almost the outside diameter of the bottle neck rim corresponds and by providing of the two grooves in the top plate can be reached in connection with the principle for all bottlenecks existing external rounding that the Sealing strip itself when screwing on the closure not just under pressure on the bottle neck hangs up, but rather stretching on the Bottle neck rim slides open.

This configuration therefore leads to the sealing strip not between bead and bottle neck only pinched in the area of the rounded transition is, but further in the annular gap between the cylindrical outer wall of the bottle neck and pulled into the cylindrical inner wall of the bead becomes. When putting on or screwing on the closure, more specifically when the Sealing strip on the top end of the bottle neck namely the essentially cylindrical one Weather strips slightly widened as a result caught on the outside by the bead and gets then in a more or less flowing state, when he goes through the bead into the narrow annular gap is drawn between the bead and the bottle neck. Because also the sealing strip in the radial direction attaches further to the head plate than the one known closure, a bulge affects Head plate in its central area practically not more on the weather strip and on yourself slight lifting of the head plate also in its outer Area where the sealing strip attaches, does not yet lead to the pulling out of the sealing strip from the annular gap, since it projects relatively far into it and over a large area clamped between the bead and the bottle neck is. The weather strip is hardly anymore on the front of the bottle neck, but only still in the rounded part and on the cylindrical Part of the bottle neck where the sealing effect should be achieved. The sealing strip in radial direction within the sealing area no noteworthy target for those under pressure standing gases or liquids inside the bottle and also has no noteworthy Free space on the back of such Attack surface on, so that this also lifting and effectively pulling out the weather strip becomes. The on both sides of the weather strip in the grooves provided in the top plate bear in this Relation to the fact that the sealing strip is sufficiently mobile and still to the end the closing process caused by striking the bottle neck edge is defined on the head plate, is pulled directly and over the bottle neck.

So that the sealing strip when screwing on even better over the outer top of the bottle neck is in the preferred embodiment the invention a bevel of the inner edge the free end of the weather strip is provided.

An embodiment of the invention is preferred, in which the transition of the cylindrical Inner surface of the bead to the level of the inner surface of the Head plate takes place along a transition surface, the Curvature of the curvature of the transition surface of the cylindrical outer surface to the front surface of the End of the bottle neck.

This avoids almost any freedom the outside of the weather strip, which - at firmly screwed closure - absolutely fixed and due to the internal pressure in the bottle can no longer be lifted from the bottle neck.

In the preferred embodiment of the invention it is also provided that the inner diameter the cylindrical wall of the bead is less than or equal to the sum of the outer diameter of the cylindrical Wall of the top of the bottle neck plus the Thickness of the weather strip is in its main part. The sealing strip is thereby securely in the annular gap between the inner wall of the bead and the outer wall of the bottle neck and pulled in there more or less clamped.

Figur 1

einen Teilquerschnitt durch einen teilweise auf einen Flaschenhals aufgeschraubten Deckel gemäß einer ersten Ausführungsform der Erfindung,

Figur 2

eine Ansicht entsprechend Figur 1 mit fast vollständig aufgeschraubtem Deckel,

Figur 3

eine zweite Ausführungsform in einer Ansicht entsprechend Figur 1,

Figur 4

die Ausführungsform nach Figur 3 mit vollständig aufgeschraubtem Deckel,

Figur 5

eine Ansicht entsprechend Figur 1 für eine dritte Ausführungsform und

Figur 6

die Ausführungsform nach Figur 5 mit vollständig aufgeschraubtem Deckel.

Further advantages, features and possible uses of the present invention will become clear from the following description of a preferred embodiment and the associated figures. Show it:

Figure 1

2 shows a partial cross section through a lid which is partially screwed onto a bottle neck according to a first embodiment of the invention,

Figure 2

2 shows a view corresponding to FIG. 1 with the lid almost completely screwed on,

Figure 3

2 shows a second embodiment in a view corresponding to FIG. 1,

Figure 4

3 the embodiment according to FIG. 3 with the cover fully screwed on,

Figure 5

a view corresponding to Figure 1 for a third embodiment and

Figure 6

the embodiment of Figure 5 with the cover fully screwed on.

The figures are only schematic representations and do not necessarily give all proportions and dimensions to scale again. As far as it is for the present invention on the relative location and Dimensions of individual elements are particularly important, this is clearly emphasized accordingly.

Figure 1 is a section along a plane which the (not shown) axis of the screw cap contains, which essentially also with the axis of the Bottle neck 7 coincides. A part is shown of the substantially cylindrical shell 1 with threads 1a, part of the circular disk-shaped head plate 2, as well as the transition between these two Split with the sealing strip 3 and the bead 4. The threads 1a engage in corresponding threads 12 on the outside of the bottle neck 7 on.

The end of the bottle neck 7 has essentially the shape of a hollow cylinder with a flat one annular end face 8c, an outer cylindrical surface 8a and a rounded transition 8b between the named areas. The manufacture of such Bottles mean that not that Face 8c, but rather the surfaces 8b and 8a the most precisely defined areas of the bottle neck with the smallest tolerance deviations. For this reason, it is appropriate to do this Area also the sealing of the plastic closure provided.

As can be seen in Figure 1, the sealing strip sets 3 relatively far outside in the radial direction Inner surface 2a of the head plate 2. The approach area of the weather strip 3 has approximately the same Outside diameter like the bottle neck and lies so far outside that the weather strip at Screwing onto the bottle neck practically only the areas 8a and 8b of the bottle neck, not however, or only to a small extent on the end face 8c of the bottle neck comes to rest.

The bevel 11 on the inside edge of the free End of the weather strip 3 ensures that the Screw the cap onto the bottle neck 7 the sealing strip 3 on the outside of the bottle neck in areas 8b and 8a. The bead 4 ensures this ensure that the sealing strip 3 firmly and sealingly the surfaces 8a and 8b of the bottle neck to the plant comes by between bead 4 and bottle neck 7 is pinched. While unscrewing swings the free end of the very thin in practice and elastic sealing strip 3 to the outside and comes first with the more or less rounded Edge 5 of the bead 4 in contact so that this edge 5 the sealing strip when screwing on further takes along and around the bottle neck and pulls down The width of the annular gap between the cylindrical inner wall 6 of the bead and the outer wall 8a of the bottle neck corresponds to that Thickness d of the sealing strip 3 above the bevel 11 or is for the purpose of achieving a clamping effect a little less.

Figure 2 shows the screw cap largely screwed on condition.

In contrast to the known embodiment with a conical inner wall of the bead 4 allows the cylindrical inner wall of the bead 4 according to the present invention so far Screw the plastic closure onto the Bottle neck that the sealing strip 3 a considerable Piece in the annular gap between bottle neck 7 and bead 4 is pulled in and so the bottle seals effectively, even if the head plate 2 bulges or when the weather strip 3 in its Neck area due to the internal overpressure in the remaining space radially outside the Sealing area is pressed. You can see in figure 2 that even in this condition, in which the plastic closure not yet completely on the bottle neck 7 is screwed on, pushing the Sealing strip 3 in the free space 13 the sealing function the lock does not yet affect would still be an essential part of the weather strip 3 the annular gap between bead 4 and Bottle neck 7 fills.

Figure 3 shows a slightly modified embodiment the invention with a slightly thicker head plate 2, with the transition between Bead 4 and head plate 2 is less rounded. As can be seen in Figure 4, this embodiment is also an effective seal guaranteed at all times. The closure can so far on one Bottle neck 7 are screwed on that the top plate 2 completely on the end face 8c of the bottle neck 7 comes to rest, being in the area of the surface 8a and especially in the area of surface 8b the seal he follows. The bead 4 in turn pulls the weather strip 3 far into the annular gap between the bead 4 and the outer cylindrical surface 8a of the bottle neck 7 in. The lower inner edge 5 of the bead 4 is slightly rounded.

The annular grooves 9 and 10 also provide sufficient flexibility of the sealing strip 3 able to soften the headstock 2 almost or completely the end face 8c of the bottle neck 7 touches. Nevertheless you can see from the Representation in Figure 4 that the sealing strip for (in Figure 4 on the right) print page only a minimal Offers attack surface, so that even with a relatively large Overpressure is not to be feared that the Sealing strip 3 is lifted off the sealing surface 8b becomes.

The latter is completely eliminated Danger from that shown in Figures 5 and 6 Embodiment. As can be seen in Figure 5, differentiates this embodiment differs from the two aforementioned embodiments essentially in that the cylindrical inner wall of the bead is somewhat shortened in the axial direction and in the form of a curved arc (in the cross-sectional view) in the plane of the inner surface 2a of the head plate 2 merges, the curvature of this arc essentially the curvature of the surface 8b of the bottle neck 7 corresponds.

As can be seen in Figure 6, this leads to the fact that at fully screwed closure on the Inside of the bottle facing away from the weather strip 3 practically no free space at all is in which the weather strip at occurring overpressure could be pressed. The tightness of such a closure is in all practical cases and for all Pressure areas ensured for which such closures are provided at all.

From the representation of the above embodiments you can see that there is a difference to that known screw cap also consists in that that of the weather strips in the sealing area between a conical and a (partially) toroidal surface is clamped. Reaching this clamping position also forms a kind Stop against further unscrewing. In contrast to this end, in the present invention Sealing strips from the bead 4 more or less drawn around the partially toroidal surface 8b and kept sealed in this position, only that Place the head plate on the end face 8c of the bottle neck 7 forms a stop in this position the sealing strip offers to those under pressure The interior of the bottle is very small Attack surface and this only in the vicinity of the comparatively rigid attachment area of the sealing strip. Because a relatively long section of the Sealing strip pulled around the sealing surface 8b and not just the extreme end of the weather strip 3 is pinched, can also Manufacturing tolerances of the bead and bottle neck Easier to cope without disadvantage, since also with Occurrence of such tolerance deviations is always a part of the sealing strip rest on the sealing surface 8b becomes.

The essentially cylindrical shape of the sealing strip 3 facilitates the manufacture of the closure, which is easier to demold than a closure with conical weather strip.

Claims (4)

1. Plastics screw closure for bottles, in particular for pressurised drinks bottles, composed of a basically cylindrical wall (1) with an internal thread (1a) and a substantially circular disc-shaped top plate (2), on the inside (2a) of which a thin annular sealing strip (3) is integrally moulded and at its junction with the cylindrical wall (1) there is provided on the inside a raised part (4) for pressing the sealing strip (3) against the upper, outer edge (8a, b) of a bottle neck (7) with a planar, annular terminal face (8c), wherein the raised part (4) is provided with an at least partially cylindrical inner wall (6) concentric to the axis of the closure, the diameter of which is slightly larger than the external diameter of the upper edge (8a) of the bottle neck, characterised in that the sealing strip (3) is configured substantially cylindrically, the external diameter of the sealing strip is approximately equal to the external diameter of the edge of the bottle neck, and that on both sides of the sealing strip (3) there is provided a continuous groove (9, 10) in the top plate (2) such that when screwed down, the sealing strip (3) between the raised part (4) and the bottle neck (7) is not only clamped in the region of the rounded transitional area (8b) between the annular end face (8c) and the external cylindrical surface (8a), but by means of the raised part (4) is drawn further into the annular gap between the external cylindrical surface (8a) of the bottle neck (7) and the cylindrical inner wall (6) of the raised part (4).
2. Plastics screw closure according to claim 1, characterised in that the inside edge of the free end of the sealing strip (3) is provided with an inclined part (11).
3. Plastics screw closure according to one of claims 1 or 2, characterised in that the transition of the cylindrical inside surface (6) of the raised part (4) and the plane of the internal surface (2a) of the top plate (2) is along a transitional surface, the curvature of which corresponds to the curvature of the transition surface (8b) of the cylindrical external surface (8a) and the end face (8c) of the end of the bottle neck (7).
4. Plastics screw closure according to one of claims 1 to 3, characterised in that the diameter of the cylindrical internal wall (6) of the raised part (4) is smaller or equal to the sum of the diameter of the cylindrical external wall (8a) of the upper edge of the bottle neck plus the thickness (d) of the main part of the sealing strip (3).

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