EP0675051A2 - Threaded cap with a welded ring - Google Patents

Abstract

The plastics screw cap, for a plastics container, has a ring clip (4) extending as a shoulder radially over the cap mantle (3) and/or at the cap. The material is suitable for welding to the container cover to be used with the closure cap. The screw cap, and the shoulder, are of polypropylene as is the container cover. <IMAGE>

Description

The present invention relates to a screw cap made of plastic for the closure of a plastic container and thus also to a screw cap closure as a whole or to a plastic container provided with such a closure.

Closures for plastic containers are known in various forms. Apart from plastic bottles, which have a tapered neck, which at least in the area immediately below the cap does not significantly exceed the cap diameter, and which are therefore not considered for the present invention, in particular canisters, buckets and the like are known, which in one section , which is referred to here as a lid, have a container closure which is inserted or also placed on a short connection piece and which is likewise made of plastic. So-called bellows closures, which are inserted with a closure foot into a container opening, are used particularly frequently, the closure foot being connected to a pouring spout via a bellows which can be slipped in, onto which in turn a screw cap is screwed. During storage and Transportes the pouring spout together with the screwed-on cap by pushing the bellows in as far as possible into the container opening, so that the upper edge of the screw cap is either flush with the edge of the closure foot or the lid surface, is below or with a protruding edge on the Dand the container opening rests. Such a screw cap usually has a ring bracket that can be folded up and that can be gripped after folding up to pull the screw cap together with the pouring spout out of the container opening and thereby to pull the bellows outwards.

In addition, closures without bellows are also known, in which a corresponding cylindrical socket with an external thread is inserted directly into the container opening or is directly connected to a corresponding closure foot. Finally, so-called telescopic closures are also known, which have a relatively long, rigid pouring spout, which in their upper and lower end regions each have locking points or stops, so that this spout can be moved axially in the container opening and for storage and transport in the container opening is pushed in as far as possible and is pulled out as far as possible for pouring and emptying the container, these two end positions being fixed by corresponding latching elements or stops.

In principle, the present invention is applicable to all of the above-mentioned embodiments, the preferred field of application being the aforementioned bellows closures and the telescopic closures.

For reasons of production that is as rational as possible, containers or container lids and closures are manufactured separately from one another, often even in completely different production sites. This is mainly due to the fact that the permissible tolerance deviations for the closures are generally much smaller than the tolerance deviations permissible for the containers themselves. Only the opening in the lid of the container, in which the closure is inserted, must be made sufficiently precise so that the closure can be inserted tightly into the opening. The closure foot, which comes into direct contact with the edge of the container opening or the inner surface of a container neck, is generally designed in such a way that, despite any deviations in the dimensions of the container opening or the container neck, a mechanically firm and at the same time leak-tight seat is achieved. The locking foot therefore mostly consists of a relatively flexible, elastic material with locking projections, sealing lips and / or similar devices, which on the one hand should ensure a tight fit and on the other hand also a tight seal. It only works The reason for this is to ensure a high degree of tightness and mechanical strength of the closure also during later use, but rather to ensure these properties during the storage and transport of appropriate containers until they are taken over by the consumer. When transporting large quantities of containers, they can fall off, for example, from shelves or from transport pallets and be exposed to relatively high mechanical loads. Furthermore, the basic principle is to avoid the danger that the contents of the container are manipulated in any way, be it that they are exchanged, mixed with foreign material or simply removed partially or completely.

In order to meet the above requirements, the container openings in question and the corresponding closures often had to be designed in a very complex manner. As already mentioned, plastic containers usually have a cylindrical screw socket, onto which an additional outer closure cap is screwed in order to hold the closure base on the container neck or the container opening. This screw cap must also be secured against loosening and it is generally also connected via tear-off webs to an inner screw cap and / or a ring bracket with which the inner screw cap and the attached spout can be pulled out of the container neck. Although simpler closure designs are already known, their use is restricted to sheet metal packaging or containers with a metallic lid, which have an opening that can be punched out relatively precisely with simple means, the opening edge optionally also being able to be formed with punching and shaping tools. The edge of such container openings is much more difficult to deform than the edge of corresponding openings on plastic containers, so that one can fall back on containers with sheet metal lids to comparatively simple closures.

Compared to this prior art, the present invention has for its object to provide a closure, and in particular a screw cap made of plastic for the closure of a plastic container, which has a similar simple structure as corresponding closures on sheet metal containers, but still a tight and tight fit of the closure at the container opening.

According to the invention, this object is achieved by a screw cap of the closure which has a projection which extends radially beyond the jacket of the screw cap and / or a ring bracket attached to the cap and which consists of a material which can be welded to the container lid.

This makes it possible to weld the approach in question to the lid of the plastic container, so that the screw cap is firmly connected to the container lid, so that all other closure parts located under the cap and the approach are securely fixed to the edge of the container opening. The welding ensures that the closure does not easily detach from the container lid or become leaky even if the container falls. Manipulations are also excluded because the closure cap cannot be moved due to the attachment firmly welded to the cover and the other closure parts are not accessible, but at least cannot be released without also breaking the connection between the attachment and the screw cap.

For the purposes of the present invention, the term "lid" generally refers to that part of the container which immediately surrounds the container opening, even if this container opening is not, for example, on the top of the container, but more or less laterally near the upper edge of a container or should be arranged on an inclined surface connecting the top and side surfaces.

It is understood that the radial extension of the approach must be sufficient to ensure contact and a welded connection between the approach and the lid material. At least the radial extension must therefore extend beyond the edge of the container opening and, if this edge is covered by any closure parts, such as a closure base, also beyond the radially outer edge of such a closure base.

Appropriately, one attachment is arranged on at least two diametrically opposite sides of the screw cap, in order to avoid lifting the screw cap or the entire closure on one side. For example, three lugs, each offset by 120 ° along the circumference, can also be arranged on the outer circumference of the cap or a ring bracket surrounding the cap. The number of approaches can also be increased further, an embodiment is generally preferred in which the approach consists of one or more ring sections.

An embodiment of the invention is particularly preferred in which the mentioned approach is designed as an essentially completely circumferential ring. The screw cap can thus be fixed along its entire circumference via the attachment on the container lid by welding the attachment to the container lid.

In detail, the circumferential ring according to the preferred embodiment has a specific cross-sectional structure that can be roughly described as an annular disk or ring flange-like part, on the outer edge of which a bead-like thickening is attached. This bead extends in the axial direction predominantly only to one side, namely to the side of the extension ring facing the cover. From the top, a circumferential groove is provided in this bead area in the attachment ring, into which an ultrasonic welding tool (sonotrode) can be inserted, while on the underside, at the same radial distance from the center that the groove has, an annular circumferential downward tapering projection is provided, which serves as a so-called direction transmitter. This projection provides only a narrow, approximately linear contact surface on the lid of the container, along which the ultrasonic energy is concentrated in the case of ultrasonic welding. Such projections on plastic parts are usually also called "direction indicators" or "energy direction indicators" because they concentrate the ultrasonic energy in a certain direction, namely the point of contact with the adjacent plastic part with which the welding is to take place.

Since the bead is relatively thick and could possibly prevent the effective transmission of ultrasonic energy for welding, the groove for receiving a sonotrode is provided in the top of the bead section just above the energy direction transmitter, so that the distance between the sonotrode and the welding point (= tip of the energy direction transmitter ) is reduced.

If the screw cap is used in conjunction with a closure which has a closure foot with an annular flange-like part which covers the opening edge, it is expedient if the axial projection of the bead-like thickening relative to the annular disk part of the extension ring corresponds approximately to the thickness of the flange part of the closure foot , In addition, the extension ring is dimensioned so that its bead portion is just radially outside the flange part of the locking foot. In this way it is ensured that, on the one hand, the bead section can be welded to the lid radially outside of the closure foot, on the other hand also the ring disk part of the extension ring rests on the flange part of the closure foot, with an annular circumferential projection on the underside of the ring disk part also being expedient has proven, which presses the flange part of the closure foot down on the edge of the container opening. Such a projection can press more or less deeply into the relatively soft material of such a closure foot and thus also compensate for any tolerance deviations and at the same time a firm and tight engagement of the closure foot with the edge of the Ensure container opening.

Insofar as a ring bracket lying radially within the extension is used to pull up the screw cap and the pouring spout screwed to it, it also appears expedient if this ring bracket has a grip tab projecting beyond the plane of the cap base, in which the attachment ring is preferably also located. This handle tab, which projects beyond the level of a shoulder ring and the cap top, can then be gripped more easily and the ring bracket can be bent upwards by lifting the handle tab, any webs which connect the ring bracket on the one hand to the cap top, on the other hand, possibly also to the neck ring, being torn off or be torn apart. In addition, the attachment ring can, however, also be connected directly to the screw cap or the top or jacket of the screw cap via rupturable webs which tear off only when the screw cap is pulled out of the state in which the container opening is inserted using the ring bracket.

In an embodiment with a raised handle tab of a ring bracket, there should be a space under the ring bracket that allows the ring bracket to be pressed down elastically, so that the upper edge of the handle tab is essentially flush with the surface of the screw cap. This avoids punctiform loads on the raised handle when stacking several containers.

The screw cap and extension ring, as well as the container lid, are preferably made of polypropylene. This material offers sufficient strength and rigidity for both the container and the screw cap.

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.

Figur 1

einen die Verschlußachse enthaltenden Schnitt durch einen erfindungsgemäßen, in eine Behälteröffnung eingesetzten Balgverschluß`

Figur 2

eine Ansicht von oben auf den entlang eines Durchmessers zur Hälfte weggeschnittenen Verschluß und

Figur 3

eine Detailansicht entsprechend dem Inhalt des Kreises Z in Figur 1.

Show it:

Figure 1

a section containing the closure axis through a bellows closure according to the invention, inserted into a container opening

Figure 2

a view from above of the closure cut away in half along a diameter and

Figure 3

a detailed view corresponding to the content of the circle Z in Figure 1.

In Figure 1 you can see a bellows closure, consisting of a screw cap 1 and a lower closure part 10. The lower closure part 10 in turn has a locking foot with an L-shaped cross section, the one L-leg 11 defines an axially extending, short cylindrical connecting piece, which in an opening of the lid 19 of a container is inserted, while the second L-leg 12 defines an annular flange which rests on the edge of the opening of the container 19. The closure foot is connected via a bellows 13 to a pouring spout 14, which has an external thread 15, onto which the screw cap 1 is screwed with its internal thread 16.

The screw cap 1 essentially consists of the screw cap jacket 3 provided with the internal thread 16, an upper base 2, a ring bracket 4 and the attachment ring 5. The attachment ring 5 in turn has a specific cross-sectional profile, which can be seen even more clearly in FIG. In detail, the extension ring 5 consists of an annular disk section or annular disk part 6 and a bead part 7 attached to it on the outside. The bead part 7 protrudes downward in the axial direction and in turn has a V-shaped tip or a projection 9 in cross section, which as Energy direction transmitter serves. Above this ring-shaped circumferential energy direction sensor 9, a likewise ring-shaped circumferential groove 8 is provided in the top of the extension ring 5, into which a sonotrode can be used, with the aid of which the projection or energy direction sensor 9 is to be welded to the material of the cover 19.

The annular disk part 6 of the extension ring 5 also has a similar, annular circumferential and V-shaped projection 18 which, however, is not to be welded to the underlying material, but rather, as can be seen on the left in FIG. 1, presses on the annular flange part 12 of the locking foot and thus ensures a firm and tight fit of the closure foot on the edge of the container opening. As can further be seen from FIG. 1, the axial projection of the bead part 7 relative to the underside of the ring disk part 6 is of the same order of magnitude as the thickness of the ring flange 12. In this way, the simultaneous engagement of the bead with the cover (by welding), and of the projection 18 with the top of the flange part 12 ensured. Due to the V-shaped cross-section, the projection 18 can also press more or less deeply into the generally relatively soft material (generally polyethylene) of the closure foot or the flange part 12 of the closure foot.

As can be seen from Figure 3, the ring bracket has a raised handle tab 17, while the ring bracket 4 itself lies in the same axial plane as the top 2, the Screw cap 1 and the washer-shaped part 6 of the extension ring 5.

The ring bracket 4, as can be seen on the left in FIG. 1, lies radially clearly within the locking foot, so that the ring bracket (mirror image also on the right side in FIG. 1) can be moved freely downward.

As can be seen from FIG. 2, there is nothing standing in the way of the elastic bending of the ring bracket 4 in the area of the sectional plane shown, since the tearable webs with which the ring bracket 4 is connected on the one hand to the screw cap, but on the other hand also to the extension ring 4, are far outside this cutting plane or in the circumferential direction spaced apart from the upstanding grip tab 17, preferably in the vicinity of a solid web 22, which offers an anchoring point with articulation points 24 for two symmetrically arranged ring brackets 4.

Figure 2 shows the closure mentioned above and from the inside to the outside you can first see the top 2 of the cap 1, followed by a gap 23 between the ring bracket 4 and the top 2 of the cap, this gap 23 being bridged by a solid web 22 , which is another diametrically opposite web (not shown). This web 22 is connected from both sides via an articulation point 24, which is formed by a section with a small wall thickness, to an annular bracket 4, which is followed by a gap again. In the vicinity of the solid webs 22, small, tearable webs 21 establish the connection between the ring bracket and the upper base 2 of the cap, while the ring bracket 4 or the web 22 are connected to the attachment ring 5 via further small, tearable webs 20. The dashed lines in the area of the ring shoulder represent the position of the projection 18 radially from the inside out, the transition 25 from the ring disk part 6 to the bead 7 and the energy direction transmitter 9.

The axially upwardly projecting grip tab 7 can be pressed down into the space or the gap between the upper base 2 of the screw cap and the attachment ring 4, it being possible to see from FIG. 1 that there is sufficient space under the ring bracket 4 to hold the pressed down Record ring bracket so that the upper edge of the handle tab 17 is approximately flush with the surface of the top and the neck ring 5 when, for example, several containers are stacked one above the other and pressure is exerted on the handle tab 17. The ring bracket 4 is sufficiently elastic to return to the starting position shown in Figure 1 when the load due to stacked containers or the like is removed.

Claims (20)

Screw cap made of plastic, for the closure of a plastic container, characterized in that it has a projection which extends radially beyond the cap casing (3) and / or an annular bracket (4) arranged on the cap and which consists of a material which is connected to the Material of the container lid, in which the closure is arranged, is weldable. Screw cap made of plastic according to claim 1, characterized in that it each has a shoulder on at least two diametrically opposite sides of the screw cap. Screw cap according to claim 1, characterized in that it has three lugs, each offset by 120 ° relative to one another along the circumference of the screw cap. Screw cap according to one of claims 1 to 3, characterized in that the extension consists of one or more ring sections. Screw cap according to one of claims 1 to 4, characterized in that the extension is designed as an essentially completely circumferential extension ring (5). Screw cap according to claim 5, characterized in that the extension ring (5) consists of an annular disc, the radially outer edge of which is designed as a bead (7) which is axially thickened relative to the annular disc. Screw cap according to claim 6, characterized in that the bead (7) extends from the annular disc (6) essentially only in an axial direction which faces the container lid when the closure is installed. Screw cap according to claim 6 or 7, characterized in that an annular circumferential, groove-like depression (8) is provided on the side of the bead facing away from the container lid. Screw cap according to one of claims 6 to 8, characterized in that the bead on its side facing the container has an annular circumferential projection (9) which tapers in cross section and which has a narrow contact surface of the bead compared to the radial dimensions of the bead (7) (7) on the container lid (19) guaranteed. Screw cap according to one of claims 6 to 9, characterized in that an annular circumferential projection (18) which tapers downwards in cross section is provided radially inside the bead on the underside of the annular disc (6) facing the container lid. Screw cap according to one of Claims 1 to 10, characterized in that it, including its extension (5), consists of polypropylene. Screw cap according to one of claims 1 to 11, characterized in that the attachment is integrally connected to the screw cap (1) via relatively easily tearable webs (20). Screw cap according to one of claims 1 to 12, characterized in that the extension is provided radially outside of a ring bracket (4) and lies essentially in the same plane with the ring bracket (4) and the upper base (2) of the screw cap (1). Screw cap according to claim 13, characterized in that the ring bracket (4) has a grip tab (17) projecting upwards over the surface of the top panel (2) and the shoulder. Screw cap according to claim 6 or one of the claims referring back to claim 6, characterized in that the bead (7) is dimensioned such that the clear distance between the ring bracket (4) and the parts of the closure or container located below it is at least approximately the extent of the protrusion the grip tab (17) corresponds to the level of the cap base (2). Screw cap according to one of claims 1 to 15, characterized in that it consists of polypropylene just like the attachment. Screw closure with a lower closure part which has a closure foot which can be fixed to a container opening and a pouring spout onto which a screw cap according to one of Claims 1 to 16 can be screwed, characterized in that at least the part of the attachment which is to be welded to the container lid, for example in particular a bead (7) according to claim 6, projects radially beyond the closure foot (11, 12) of the closure lower part. Screw closure according to claim 17, characterized in that it is designed as a bellows closure. Container made of plastic with a screw cap closure, characterized in that a radial extension projecting beyond the jacket of the screw cap is welded to the container lid. Container according to claim 18, characterized in that at least the container lid and the screw cap with shoulder are made of polypropylene.

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