EP0451102B1 - Plastic closure - Google Patents

Abstract

A plastic closure (1) is provided with a tamper-proof strip (2). The closure (1) and tamper-proof strip (2) are connected to one another by connecting webs (4). The connecting webs (4) are weakened on one side facing the intended tearing point (P). <IMAGE>

Description

The invention relates to a sealing cap made of plastic with a guarantee band according to the preamble of patent claim 1.

Such caps with a guarantee band, which is connected to the cap with a plurality of connecting webs, are becoming increasingly popular with consumers. The guarantee band is designed in such a way that it is attached to the neck of the container by shrinking or by positive locking or by molding on corresponding beads, cams or in undercuts. When the cap is opened for the first time, such a resistance is built up by the guarantee band connected to the neck of the container that the connecting webs at least partially tear, so that the first opening of the closure cap is indicated (tamper evidence).

In some versions of the guarantee band, a vertical (or more vertical) predetermined breaking line is also provided in addition to the connecting webs on the guarantee band itself. Sealing caps are known both as screw caps with an internal thread and as snap caps or with other forms of fastening to the container neck (e.g. bayonet-type locking).

An embodiment of such a closure cap is known from EP patent 154 603. There is shown a screw cap with a so-called mechanical guarantee band, which snaps over a complementary bulge on the container neck when it is first put on with several retaining cams and a bead on the guarantee band. The guarantee tape is permanently connected to the screw cap on one side with a web.

This closure cap according to EP patent 154 603 and also the other types and types of the types of closure caps described at the outset can be further improved with regard to their guarantee properties. A problem with the known caps is that the connecting webs should be sufficiently strong and resilient, on the one hand, to prevent them from being handled, from being ejected from injection molds, from being stored in large containers or from being screwed onto the bottle and from being snapped over a container bead or during thermoforming to tear or get damaged. On the other hand, each connecting bridge should be extremely sensitive to any type of tensile load, in order to tear as early as possible when it is first unscrewed and to reliably fulfill its guarantee function. These conflicting requirements are particularly difficult to meet with mechanical guarantee tapes. There, namely, when the cap is screwed on, a relatively large load is exerted on the connecting webs if the guarantee band snaps over the complementary bead on the bottle or the container.

The invention has for its object to avoid the disadvantages of the known, in particular to create a closure cap of the types described above, which on the one hand fulfills its guarantee function well, i.e. that is, it tears quickly and reliably when opened, but which, on the other hand, has sufficient stability for the entire manufacturing and handling process.

According to the invention, this is achieved according to the characterizing part of patent claim 1.

According to the invention, such a closure has a plurality, that is to say at least two, but preferably at least four, connecting webs. At least two webs adjacent to a certain point are facing at this point Side weakened. During the opening process, this weakening means, for example, a greater tendency to tear, so that whenever a tensile load is exerted on the guarantee tape from this point, a crack virtually propagates laterally away from the stated point through the adjacent and subsequent connecting webs.

Means should preferably be provided to provoke the start of the crack at a certain point on the circumference of the guarantee band. This can e.g. can be achieved in that at one point the holding cams are designed, in particular raised or deepened, that tensile forces are introduced into the guarantee band there when they are opened. It is also conceivable to firmly and permanently connect the guarantee band at one or more points with a screw cap, so that when the closure is opened it is forced to "dodge" on the opposite side and there to put more strain on the guarantee band, which then affects this Make the crack start provoked. This effect can be achieved particularly reliably if the zone of the fixed connection between the guarantee band and the screw closure is provided over a circumferential angle of 130 ° to 240 °. Particularly good results are obtained at around 180 ° to 210 °.

Alternatively, it is therefore conceivable to divide the guarantee band into two or three sections, each of which is permanently connected to the screw cap by means of a fixed web, and then to provide points with a predetermined start of the crack in the segments delimited by the fixed webs.

The invention can be implemented in a technically particularly simple manner if the connecting webs are tapered in cross-section to the location of the intended crack start. The cross-sections of the webs can thus be, for example, “wedge-shaped”. "Wedge-shaped" also captures such configurations in which one or more of the side surfaces of the wedge are concave or convex curved. In any case, it is essential in the first place that the side of the connecting web facing away from the intended crack location is thicker and mechanically stronger than the side facing the intended crack location, and that usually two adjacent webs are weakened symmetrically towards the crack location . There may be applications in which it is sufficient to form the two connecting webs immediately adjacent to the intended crack location in the manner described and to shape the remaining webs in the usual way. This can be possible because the start of tearing is particularly critical with guarantee tapes. As soon as the guarantee band is torn and sags at a point P or runs diagonally to the screw cap, the free cross-section tapers and it jams under the complementary bead at the bottle opening. It can then no longer be raised in parallel with the cap, as would be possible, for example, at the beginning of an opening process, and snapped upwards via a complementary bead or a depression in the bottle opening.

If the cross section of the connecting webs is approximately wedge-shaped, a wedge angle of approximately 15 ° to 30 ° and preferably approximately 20 ° is particularly suitable for the invention. It has been shown that wedge tips with this angle tear relatively quickly under tensile load, while the thickened side facing away from the rice pad is sufficiently stable to ensure manipulation and handling of the screw cap before putting on and when putting on without breaking the connecting webs.

However, the connecting web can also be weakened in another way and, for example, cut horizontally or provided with one or more notches.

Figur 1

die schematische Darstellung eines Querschnitts durch einen Verschluss mit den Merkmalen der Erfindung,

Figur 2

eine Ansicht von unten auf den Verschluss gemäss Figur 1,

Figur 3a

ein Schnitt längs der Linie A-A gemäss Figur 1 in vergrössertem Massstab und im Ausschnitt,

Figur 3b

eine Ansicht der Darstellung gemäss Figur 3A,

Figur 4

eine Verschlusskappe mit Schraubgewinde im Moment des Abschraubens von einer Getränkeflasche,

Figur 5a

ein abgewandeltes Ausführungsbeispiel eines Schraubverschlusses mit zwei dauerhaften Verbindungsstegen,

Figur 6

die schematische Darstellung eines Verschlusses mit mechanischem Garantieband,

Figur 7 a

und

Figur 7b

schematische Darstellung eines Verbindungsstegs mit keilförmig zulaufender Spitze,

Figur 8a

und

Figur 8b

das abgewandelte Ausführungsbeispiel eines Verbindungsstegs, sowie

Figur 9

ein weiter abgewandeltes Ausführungsbeispiel mit Verschlusskappe.

The invention is explained below in exemplary embodiments with reference to the drawings. Show it:

Figure 1

the schematic representation of a cross section through a closure with the features of the invention,

Figure 2

2 shows a view from below of the closure according to FIG. 1,

Figure 3a

2 shows a section along the line AA according to FIG. 1 on an enlarged scale and in the detail,

Figure 3b

3 shows a view of the illustration according to FIG. 3A,

Figure 4

a cap with screw thread when unscrewing from a beverage bottle,

Figure 5a

a modified embodiment of a screw cap with two permanent connecting webs,

Figure 6

the schematic representation of a closure with a mechanical guarantee band,

Figure 7 a

and

Figure 7b

schematic representation of a connecting web with a tapered tip,

Figure 8a

and

Figure 8b

the modified embodiment of a connecting web, and

Figure 9

a further modified embodiment with a cap.

According to FIGS. 1 and 2, a closure cap 1 produced by the injection molding process is provided with a guarantee tape 2. The closure cap 1 is permanently connected to the guarantee band 2 by means of a web section 3 over a circumferential angle alpha of approximately 210 °. In the area of the remaining circumferential angle, however, the guarantee band 2 is connected by five connecting webs 4.

The guarantee band 2 has on its inside a circumferential bead 5 with which the guarantee band 2 underneath can engage a complementary bead 6 on a beverage bottle. The bead 5 runs downward at an acute angle, so that the guarantee tape 2 can be slowly stretched when screwed onto the bottle and snapped over the complementary bead 6 on the bottle neck.

Since the guarantee band 2 is also provided with the bead 5 in the region of the web section 3, an increased tensile stress is exerted on the side opposite the web section 3 approximately in the direction of arrow A when it is first opened. This results from the fact that when the bead 5 is unscrewed in the area of the tear-off webs, due to the enlargement of the bead in this area, it comes into greater engagement with the complementary bead 6 on the bottle neck 7. In addition, the bead 5 in the web area 3 is pressed away from the container neck in the direction of arrow B according to FIG. 1, as a result of which it engages more firmly on the opposite side and thereby reliably tears at the beginning of the opening. The tearing of the connecting webs 4 is therefore particularly provoked in the area between the two connecting webs 4a and 4b.

As can be seen particularly well from FIGS. 2 and 3, the webs 4 are approximately wedge-shaped, with all webs with their wedge tip, i.e. that is, their thinner and weaker edges are directed to point P, where the tearing process is to begin.

As can be seen particularly well from FIG. 3b, the guarantee band 2 forms a downward "loop" after the start of the tearing process, because the closure is tilted somewhat on the bottle neck 7. As soon as this position is reached, the tearing process propagates quickly from the point P over the other webs 4 when the closure cap 1 is opened further. This loop formation in the direction of arrow C can also be seen particularly well from FIG. 4.

The connecting webs 4 tapering in the direction of the point P are provided on each side facing away from the point P with a thickened section which ensures that the guarantee tape 2 is not damaged during handling or during manufacture, in particular when ejecting from an injection molding tool that in particular the connecting webs 4 do not break or tear.

Of course, the cross section of the guarantee band can also be modified, e.g. the taper to the "wedge tip" may be pointed or blunt, depending on the plastic material used and the container or closure configuration. The thickness and the total length of the webs 4 and the width of the reinforced end facing away from point B can also be adapted to the special circumstances, in particular the tear resistance of the plastic used and the load-bearing capacity of the connection between the guarantee band and the container.

The length of the web section 3 can obviously also be optimized by simple tests. For example, very good results can be achieved with circumferential angles alpha of 170 ° to 210 °.

FIG. 4 shows an exemplary embodiment in which a heat-formable guarantee tape 2 was tapered and molded on in a known manner below a bead 6 on the container according to FIG. 7 by pressing or shrinking. The cross-sectional shape of the connecting webs 4 corresponds to the exemplary embodiment according to FIGS. 1 to 3.

Figure 5 shows a modified embodiment in which two relatively narrow web sections 3 are provided. In this case, the "loop formation" described above occurs when the closure is opened at the two points C1 and C2 between the two web sections Insert 3a and 3b.

For this reason, the connecting webs 4 are directed towards the two points P1 and P2 analogously to the exemplary embodiment according to FIGS. 1 to 4, with their tapering sides, so that the cracking process can be reliably initiated there.

FIG. 6 shows an exemplary embodiment of a closure cap 1 in which the distance a2 from the apex of the bead 5 to the upper edge of the guarantee band in the region of the point P is smaller than the distance a1 on the opposite side. Accordingly, in the area of the smaller distance a2, when the inner bead 5 is screwed on, the complementary bead 6 (FIG. 1) will first come into engagement on the container neck 7. The train on the guarantee tape 2 thus begins in the area of the point P, so that loops are formed in the direction of the arrow C.

Thus, while in the exemplary embodiment according to FIG. 5 the start of the crack is determined solely by the stretching and loop formation of the guarantee band in the area of greatest weakening, i.e. Thus, starting at points P1 and P2, means are provided in the exemplary embodiment according to FIG. 6 as well as in the exemplary embodiments according to FIGS. 1 to 4 in order to particularly provoke the start of the crack at a specific point. This is also achieved by cams or deeper bead formation.

Figures 7a and 7b show the shape of the connecting webs 4 schematically and on an enlarged scale. The connecting webs 4 are accordingly formed with a section 4c which is approximately rectangular in cross section, which merges into a tapering section 4d in which the plastic material is particularly stretchable due to its elasticity and thus tends to yield. This stretch leads to the above described loop formation, from which the cracking process is derived directly.

FIG. 8 shows a modified exemplary embodiment, in which the webs 4 are additionally weakened in their lower region by a notch 8. Every pull in the direction of arrow C causes the guarantee strip 2 to tip down, which causes the crack to start.

Of course, the notch could also have a different geometric shape and e.g. be provided in the middle section of the connecting web 4, the weakening could be formed as a perforation on one side of the connecting web 4 or subsequently made as an incision. Above all, it is important that at least two of the connecting webs 4 are weakened on their mutually facing sides in such a way that increased stretching begins there at the beginning of the screwing-on process and loop formation of the guarantee band is made possible.

FIG. 9 shows an exemplary embodiment of a closure cap 1 with a guarantee band 2 with an inner bead 5. An elevation 8 is provided on the inner bead 5, which at this point causes firmer and earlier engagement with a complementary bead 6 (FIG. 1) of a container neck 7. When the closure cap is opened, the tensile stress on the guarantee strip 2 thus begins in the area of the elevation 8, with which the point P of the intended crack formation is predetermined there.

Claims (9)

1. A closure cap of plastics material having a guarantee strip (2) which is intended to be brought into engagement with one or more retaining elements (6) on a container neck (7), wherein the closure cap (1) and the guarantee strip (2) are connected by a plurality of connecting web portions (4) which break or tear when the bottle is first opened, characterised in that the web portions (4a, 4b) in the area around at least one selected location (P) of the guarantee strip, which location is particularly loaded when the container is opened for the first time, are particularly weakened by the web portion cross-section being weaker, that is to say more sensitive to beginning tearing, at one side at its side which is towards said location (P), than at its side which is remote from said location (P).
2. A closure cap according to claim 1 characterised in that there are provided means for defining the location of the beginning of tearing at the periphery of the guarantee strip (2) and that at least the connecting web portions (4a, 4b) which are adjacent to the location (P) of the intended beginning of tearing are of a cross-section which is weakened at its side towards the location (P) of the beginning of tearing.
3. A closure cap according to claim 1 or claim 2 characterised in that the cross-section of the connecting web portions (4) decreases towards the location (P) of the intended beginning of tearing.
4. A closure cap according to one of claims 1 to 3 characterised in that the connecting web portions (4) are approximately wedge-shaped in cross-section, the tip of the wedge configuration being towards the location (P) of the beginning of tearing.
5. A closure cap according to one of the preceding claims characterised in that, as the means for defining the location (P) of the intended beginning of tearing, the closure band is provided at a side of the guarantee strip which is approximately opposite the location (P) of the beginning of tearing with a web section (3) which extends over a given angular region and which fixedly connects the guarantee strip (2) to the closure (1).
6. A closure cap according to claim 5 characterised in that there are provided at least two web sections (3).
7. A closure cap according to one of preceding claims 3 to 6 characterised in that the angle of narrowing or the wedge angle of the web portion or portions (4) is about 15° to 30°.
8. A closure cap according to claim 7 characterised in that the angle is about 20°.
9. A closure cap according to one of the preceding claims characterised in that the web section (3) with which the guarantee strip (2) is fixedly connected to the closure cap (1) extends over a peripheral angle of 130° - 240° and preferably 180° - 210°.

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