EP0524278B1 - Hinged snap closure made of plastics material - Google Patents

Abstract

The invention concerns a plastics closure comprising a lower part (1) and an upper part (2) connected to each other by a main hinge (3). Located on the closure are tensioning elements (8) whose length varies under the action of a tensile force, thus producing the required snap effect. The tensioning elements (8) are disposed in planes extending between their attachment points (4, 5). Each tensioning element is made up of several sections (10) which produce the change in length. These sections can be C, U or O-shaped. The tensioning elements (8) permit a maximum change in length of about 10-50 %.

Description

The present invention relates to a plastic snap hinge closure consisting of a lower part and an upper part connected therewith via a film hinge, the closure jacket walls running straight or curved in the area of the hinge and having at least one tensioning element integrally connected to both locking parts, and that the at least one tensioning element is central or has an attachment point on the jacket walls of both parts.

Plastic snap hinge closures of the type mentioned at the outset are known, for example, from the applicant's two European patent specifications No. 0,147,423 and No. 0,291,457. While in the first-mentioned patent the tensioning elements are tensioning straps, which are molded on brackets on the outer wall of the lower part and the cover and thus lie in one plane, are in second mentioned patent the tensioning straps arranged at least approximately in or on the jacket wall.

In the first example mentioned, the tensioning straps in the closed state run in one plane and the attachment points of the tensioning straps are moved out of the jacket wall by the brackets so that they are parallel to the main axis. In the second example, the tensioning straps run in two planes that form an angle to one another. As a result, the outer phases of each strap have to travel a longer distance when opening than the inner phases of the strap, which are closer to the hinge.

In a third variant according to European Patent No. 0'056'469 (Wiesinger), instead of tensioning straps, triangular intermediate elements were shown, which merge with the tip into the main hinge.

With regard to the explanation of the mode of operation of the various snap hinge locks, it was believed in the case of the first two patents that the tensioning straps would stretch elastically and thus cause the snap effect. In fact, however, the plastics used for plastic closures have little ability to stretch elastically. This means that the snap action does not actually work in this way.

The mode of action is correct in the third variant, explained in accordance with European Patent No. 0'056'469. It is pointed out here that the action of the snap hinge is based on the elastic deformation of the closure in the area of the hinge. This means that with each opening or closing of the closure, the outer wall of the lower part or lid, or the lid as a whole, bulges during actuation in the area of overcoming the dead center position and then bends back into the relaxed, undeformed shape.

Of course, this is an undesired interaction of hardly predictable and complex interacting forces. The snap effect can only be determined empirically and is hardly predictable. The results of snap locks that work with a toggle lever, one lever in the top surface of the lid and the other lever in the outer wall of the lid and the lower part, are much easier and more predictable. With these fasteners, the snap action depends on the force required to deform the two levers of the toggle lever. However, such a hinge is only suitable for closures with a small spout, in which the lid is not itself closes the spout, but a sealing element located on it, which interacts with the spout because the lid itself cannot be sealed due to the incisions along the lever.

From CH-A-488 085 a one-piece hinge-like joint made of plastic is known, which is used in particular for the joint connection of two plates. The hinge strip has in the transition area between the respective hinge plate and a thickened section a corrugated section with material thinning, which serves both to change the length and also acts as a pivot axis. It is also proposed to use such joints for one-piece containers with a lid. The hinge strip then engages on the cover surface of the cover on the one hand and on the side wall of the container on the other hand, the cover and side wall having to be cut in the region of the hinge strip.

There is therefore a desire to create snap hinge locks, the snap action of which does not depend on the elasticity of any part of the lock, with the exception of the tensioning elements. The object of the present invention is to provide a plastic snap hinge closure according to the preamble of the claim, in which the snap action can be achieved from the at least one tensioning element itself.

This object is achieved by a plastic snap hinge closure of the type mentioned at the outset, in which the connection points are formed by film hinges and the at least one tensioning element consists of a plurality of expandable sections which, when the closure is closed, as a whole or with repeating areas of the sections at least approximately in the plane between the Connection points runs, and that each section carries out a change in length by elastic deformation when the closure is actuated.

Figur 1

ist eine schematische Funktionsdarstellung der Schnappwirkung eines erfindungsgemässen Schnappscharnierverschlusses, welches mit einem längenveränderbaren Spannelement ausgerüstet ist;

Figur 2A+B

je eine perspektivische Ansicht eines runden Schnappscharnierverschlusses zur Erläuterung der Anordnung der Spannelemente, beziehungsweise des Spannelementes bezüglich dem Hauptscharnier;

Figuren 3a-5

zeigen drei verschiedene Ausgestaltungsformen längenveränderbarer Spannelemente an runden Verschlüssen, jeweils in der Variante a in der rückwärtigen Seitenansicht auf das Scharnier des geschlossenen Verschlusses und b im jeweils vollständig geöffneten Zustand derselben Schnappscharnierverschlüsse;

Figur 6a

zeigt eine weitere Variante des Schnappscharnierverschlusses an einer Schachtel und

Figur 6b

einen vertikalen Teilschnitt durch die Schachtel entlang der Linie A-A nach Figur 6a;

Figur 7

zeigt das Spannelement nach Figur 6 in der Anwendung an einem runden Verschluss in dessen vollständig geöffneten Lage;

Figuren 8a-d

zeigen eine Konstruktionszeichnung des Spannelementes gemäss in den Figuren 3a und b im Detail, einmal in der Seitenansicht entsprechend in der vollständig geöffneten Herstellungslage des Verschlusses und

Figur 8b

dasselbe Spannelement in seiner Lage des vollständig geöffneten Verschlusses,

Figur 8c

in der Totpunktlage des Verschlusses bei maximaler Dehnung und

Figur 8d

in der vollständig geschlossenen Lage.

Further advantageous embodiments of the subject matter of the invention emerge from the dependent claims and are in the following description with reference to the drawing explained. It shows:

Figure 1

is a schematic functional representation of the snap action of a snap hinge closure according to the invention, which is equipped with a length-adjustable clamping element;

Figure 2A + B

each a perspective view of a round snap hinge closure to explain the arrangement of the tensioning elements or the tensioning element with respect to the main hinge;

Figures 3a-5

show three different embodiments of length-adjustable clamping elements on round closures, each in variant a in the rear side view of the hinge of the closed closure and b in the fully opened state of the same snap hinge closures;

Figure 6a

shows a further variant of the snap hinge closure on a box and

Figure 6b

a vertical partial section through the box along the line AA of Figure 6a;

Figure 7

shows the clamping element according to Figure 6 in use on a round closure in its fully open position;

Figures 8a-d

show a construction drawing of the tensioning element according to in Figures 3a and b in detail, once in the side view corresponding in the fully open manufacturing position of the closure and

Figure 8b

the same tensioning element in its position of the fully opened closure,

Figure 8c

in the dead center position of the closure with maximum stretch and

Figure 8d

in the fully closed position.

The mode of operation of the closure according to the invention is explained in the schematic illustration according to FIG. The lower part of the closure is identified by 1, which can be placed on a container, for example. The lower part 1 is covered by an upper part 2 in the closed state of the closure. The upper part thus forms a lid or cap for the lower part 1. The two parts 1 and 2 are integrally connected to one another via a film hinge 3. The film hinge forms the axis of rotation, with respect to which the upper part 2 can be pivoted to the lower part 1 by approximately 180 °. The film hinge 3 is offset with respect to the outer wall 6 of the lower part 1 and the outer wall 7 of the upper part 2 aligned therewith. In order to be able to inject the closure in the fully opened state, the film hinge 3 must lie outside of the jacket walls mentioned. Reference number 8 denotes a schematically illustrated tensioning element. It has an upper connection or attachment point 4 with which the tensioning element 8 is fastened to the upper part 2 and a lower connection or attachment point 5 with which the tensioning element 8 is fastened to the lower part 1. Since both the axis of rotation, formed by the film hinge 3, and the upper attachment point 4 of the tensioning element 8 are arranged firmly on the closure, the upper attachment point moves 4 on an arc of a circle with the radius r around the film hinge 3. However, the tensioning element 8 is not fastened in the region of the axis of rotation 3, but rather at the lower attachment point 5 and would therefore like to rotate about this point. If the clamping element 8 could not be extended, the upper attachment point 4 would have to move on an arc of a radius ℓ, where ℓ corresponds to the length of the clamping element. The difference between these two radii with different axes of rotation inevitably leads to a change in the length of the clamping element 8. This change in length is shown in the drawing as ℓ.

This change in length produces the force required for the snap action. How the tensioning elements can be designed in order to be able to carry out such a change in length will be described below. The force with which the closure exerts a snap action is therefore dependent on relatively simple geometric considerations. In contrast to the snap hinge locks described in the introduction, the barely detectable change in shape of the lock itself plays no role in the mode of operation described here. The degree of elasticity can be influenced by the design of the tensioning elements. The maximum length change Δℓ and the location of the dead center position are essentially only depending on the arrangement of the attachment point 4 and 5, with respect to the film hinge 3. The designer thus has great degrees of freedom with regard to the design of a closure according to the invention. If, for example, in the variant shown, the two attachment points 4 and 5 are kept inward while maintaining the length of the tensioning element 8, the radius r is increased and accordingly Δℓ and the angular position of the dead center change accordingly. The optimization of the snap effect can be derived directly from the drawing without experimenting. If the possible change in length .DELTA..phi. Is relatively large, the tolerance with regard to the arrangement of the attachment points of the tensioning element is also wide. This is in stark contrast to the previously known plastic snap hinge locks, which only allow a small tolerance with regard to the geometric design.

Figures 2a and 2b each show a snap hinge closure in a perspective view to explain the possible arrangement of the snap hinge. The variant according to FIG. 2a shows a relatively narrow film hinge 3, by means of which the lower part 1 is hingedly connected to the upper part 2 and, on both sides, a tensioning element arranged at the same distance from the film hinge 3 8. In contrast to this, the variant according to FIG. 2 shows two film hinges 3 at a certain distance from one another and a tensioning element arranged in the middle between them. In the construction of non-cylindrical plastic closures, various combinations of one or more film hinges with one or more tensioning elements can be realized .

FIGS. 3a, b-5a, b show three variants of plastic snap hinge locks according to the embodiment according to FIG. 2a, which differ only in the design of the tensioning elements 8.

If one looks at FIGS. 3a, 4a and 5a, each of which shows the rear view of a closed closure, it can be seen that the attachment points 4, 5 of each individual tensioning element 8 each run parallel to one another when the closure is closed. In contrast, FIGS. 3b, 4b and 5b show the hinge areas of the corresponding closures in the fully opened position thereof. In this position, the connection points 4, 5 each run obliquely to one another. When designing the tensioning elements 8, one can proceed in such a way that in the fully open position of the end, as shown in FIGS. 3b, 4b and 5b, the tensioning elements lie stretched in one plane, but completely are relaxed. This would correspond to the manufacturing situation. With this design of the tensioning elements, they would already be slightly stretched in the closed state of the closure. The clamping elements thus exert a certain closing force even when the closure is closed. On the one hand this strengthens the snap effect and on the other hand the closing movement of the snap effect is maintained until the very end.

In the examples shown, the connection points of the tensioning elements 8 are each arranged at least approximately flush with the jacket walls. However, this is not necessary. The connection points 4, 5 could easily merge into brackets that are molded onto the jacket walls and protrude from them. This variant will be used in particular if you want to attach the clamping elements 8 to a round closure relatively far away from the main hinge 3. In this case, however, a variant can also be envisaged in which the attachment points of the tensioning elements run obliquely to one another. The arrangement of the tensioning elements relative to the main hinge 3 and the position of the attachment points 4, 5 relative to one another will influence the choice of the shape of the tensioning elements or their partial sections.

The embodiment according to Figures 3a and b show clamping elements 8, which consist of three c-shaped sections. The three c-shaped sections form a meandering band which runs in a plane between the two attachment points 4 and 5. The change in length of the clamping elements 8 takes place by the expansion of the sections 10. The more the clamping elements 8 are stretched, the more the c-shaped partial elements 10 are spread. The opening direction of the c-shaped sub-elements 10 alternate in this embodiment. However, this is by no means absolutely necessary.

Figures 4a and 4b show a variant in which the tensioning elements do not consist of identical sections. While the sections that adjoin the attachment points 4, 5 are semi-elliptical sub-elements 11, a completely elliptical sub-element 12 is arranged in between. Of course, a clamping element 8 could also consist of three such elliptical, o-shaped partial elements. It is only a question of definition, because with the same right one could recognize five C-shaped sub-elements in this form. The more the length of the clamping elements 8 is changed here, the more the elliptical partial elements are stretched into circular elements.

The embodiment according to FIGS. 5a and b shows almost identical clamping elements as those in FIGS. 3a and 3b.

The subsections 10 are only arranged differently here.

FIG. 6 shows that the use of the snap hinge closure according to the invention is not limited to the use of round or otherwise shaped closures of containers. Here, the snap hinge according to the invention is attached to a can 20. The lower can part 21 is connected to the can lid 22 via the main hinge 23. With 28 the two clamping elements arranged on both sides of the main hinge 23 are designated.

Each clamping element 28 consists of four U-shaped partial elements 24. In contrast to the previously described embodiments of the clamping elements, the partial sections 26 here do not run within the plane that is spanned between the attachment points 24 and 25, but meandering from the plane between the two two starting points. In the example shown, the tensioning elements consist of a plurality of U-shaped sections which are lined up in such a way that they have an area which is rounded inward with respect to the closure and outwardly flat with respect to the closure. The flat areas 30 are arranged so that they are closed State of the closure in an aligned plane common to the jacket walls. The rounded areas 31 of the sections 26, however, protrude somewhat with respect to the casing wall into the can. Such a design of the clamping element is not only suitable for cans, but also for closures that are applied to a container. In this variant of the tensioning element, too, the change in length is achieved by spreading out the U-shaped partial elements 26.

The tensioning elements are formed by film hinges in the area of the connection points. This has the advantage that the tensioning elements always run in the plane between the two attachment points, regardless of the opening position of the closure or cover. In particular, this simplifies the design of the injection mold.

If such a tensioning element 28 is attached to a round closure, as shown in FIG. 7, the partial sections 26 form a fan-shaped, length-adjustable band in the fully opened state of the closure.

A tensioning element 8 corresponding to the embodiment according to FIG. 3a is shown in detail in FIGS. 8a-8d. Figure 8a shows a partial side view of the closure in the hinge area. The representation corresponds to the spray position in which the closure is fully open. The lower part 1 is in turn connected to the upper part 2 via a film hinge. The tensioning element 8 runs completely flat here and the attachment points 4, 5 are arranged in niches 14, 15 in the upper or lower part. 8b shows the same situation in the top view of the tensioning band. The drawing level is the level that is spanned by the attachment points 4 and 5. If one measures the distance between the centers of the two attachment points 4 and 5, which lie on the line BB, it is found that the distance is the smallest in this position. This distance a is 4.7 mm in the real example shown here on a scale of 10: 1. In FIG. 8c, on the other hand, in which the closure is shown in its dead center position, the tensioning element 8 has been changed to its greatest length, that is to say the individual partial elements are most widely spread. The distance a has increased to 6.6 mm here. This corresponds to a percentage increase in length of around 40%. In the closed state of the closure, which is shown in FIG. 8d, the distance between the two attachment points 4.5 is still 5.0 mm. Consequently, the clamping element 8 is also closed Condition of the closure still under tension.

Compared to the relaxed position according to FIGS. 8a and 8b, the change in length still bears more than 6%.

The maximum elastic change in length of the tensioning elements will preferably be selected between 10 and 50%.

However, this depends very much on the geometric conditions. In addition to the percentage change in length, the tensile force exerted by the tensioning element is also important. This is influenced on the one hand by the geometrical design of the clamping element and on the other hand by the material thickness of the sections. However, so that there is no deformation of the closure itself, it makes sense to make the wall thickness of the partial sections considerably smaller than the wall thickness of the jacket walls in the area of the attachment points. If you choose the maximum elastic length change in percent too small, a snap action only takes place in the area of the dead center. A 10% change in length in the dead center area should make sense as the lower limit.

As the few selected examples according to the attached drawing have already shown, the wealth of the different variants in the design of the closures according to the invention is almost unlimited. But this is extremely for plastic snap hinge locks significant advantage. Almost every manufacturer of cosmetic products, foodstuffs or technical chemicals wishes for their products to have their own design adapted to the packaging. With the present hinge, the designer now has almost unlimited possibilities.

Claims (11)

1. Plastic snap hinge closure comprising a base (1) and a top (2) connected thereto by means of a film hinge (3), the closure walls (6, 7) being straight or curved in the vicinity of the hinge and have at least one fixing element (8) connected in one piece to the two closure parts and that the at least one fixing element has directly or indirectly in each case one attachment (4, 5) to the jacket walls of both parts, characterized in that the connection points are formed by film hinges and that the at least one fixing element comprises several expandable partial sections, which in the closed state of the closure totally or with repeating areas of the partial sections are at least approximately in the plane between the attachment points (4, 5) and that each partial section performs a length change by elastic deformation during the operation of the closure.
2. Closure according to claim 1, characterized in that the connection points of the at least one fixing element are fitted to brackets projecting with respect to the jacket walls.
3. Closure according to claim 1, characterized in that the connection points of the at least one fixing element are flush with the jacket walls.
4. Closure according to claim 1, characterized in that the connection points of the at least one fixing element are parallel to one another.
5. Closure according to clam 1, characterized in that the connection points of the at least one fixing element are inclined to one another.
6. Closure according to at least one of the claims 1 to 5, characterized in that there is only one fixing element, which is arranged between two film hinges connecting the two closure parts in hinging manner.
7. Closure according to at least one of the claims 1 to 5, characterized in that there are two fixing elements, which are arranged symmetrically on either side of a film hinge connecting the two closure parts in hinging manner.
8. Closure according to claim 1, characterized in that the partial sections are arcuate sections passing into one another and which form a band meandering in the plane between the two attachment points.
9. Closure according to claim 1, characterized in that at least one fixing element comprises partial sections, which are arranged so as to meander in harmonica-like manner out of the plane between the two attachment points.
10. Closure according to claims 5 and 9, characterized in that the partial sections form a fan-like, length-variable band.
11. Closure according to claims 1 to 10, characterized in that the fixing elements allow a length change of 2 to 25%.

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