EP0911272B1 - Container and closure as well as method of manufacturing the closure - Google Patents

Description

The invention relates to a method of making a Insert lid according to the preamble of the claim 1.

Such plug-in lids have so far been made of plastic and have a radially outward-facing stop that is in the inserted state supported on the open edge of the can, e.g. according to US-A-4,088,242; they are problematic due to disposal.

The common cardboard cans are mostly used as packaging, which are removed after their intended use. To enable simple and inexpensive recycling, the Cans and lids made from one and the same, easily recyclable material be trained. So that means that end floors and covers should be made of cardboard and / or strong paper. For cans that for the absorption of damp or goods to be protected from moisture, In particular, foods are suitable, such as cardboard boxes and Cardboard lid with metal, especially aluminum, but possibly also used with plastic layers.

Over-slip and insert lids have already been made from cardboard and paper. Since the attached lids must seal the inside of the can tightly, problems arise when using cardboard and / or paper, because components made from these layer materials are not very large Accuracy can be established. The big tolerances with which have to be reckoned with, especially because that cardboard and paper on environmental influences, especially on different ones Humidity, react with changes in size. A well-known insert lid includes a flat end surface made of semi-cardboard or solid Paper placed at its circular edge in a cylindrical contact area

The end surface with the cylindrical contact area is produced from flat flat material by a punching and pressing process. At the free or open end of the contact area there is half inside folded cardboard cylinder section placed and glued to it attached. The folded cardboard cylinder section encloses a partial area of the contact area and forms the Grip rib and on its outer edge that on the edge of the can opening attachable stop area. The contiguous contact areas the lid and the can must be dimensioned so that the lid can be inserted even with different air humidity or is removable. When inserting a cover, the scope of its contact area The lid can be slightly above the circumference of the socket contact area be irreversibly deformed, for example by wrinkles in the contact area and especially in the end area. To moisture-related To reduce inaccuracies, the lid outer surfaces are about one moisture-resistant coating. For material-related reasons of tolerance can not rule out the mentioned wrinkling become.

Plug-in lids have also been proposed which consist of 3 or more Cardboard parts are made, e.g. according to US-A-2'638'820, or one initially to form plug-in lid hanging on the can jacket (DE-A1-4023996), by inserting the end face of the can jacket along a circumferential - according to EP-A1-668'151 for training a kind of hinge - broken tear line is broken, which is the formation of a membrane spanning the can edge is impossible and an industrially very difficult to control, very precise Depth of cut required so as not to injure the end membrane. Both are relatively cumbersome training, their production is relative expensive comes.

A better variant is described in DE-U-9319903 (corresponds to the preamble of claim 1); she avoids the problems with the exact cutting depth because the insert lid is independent is made from the can jacket; 'but it is the final membrane encompassing ring designed to stop on the edge of the can complicated.

The invention has now taken on the task of a box with a plug-in lid training that is very inexpensive to manufacture and the problems mentioned does not have; the contact area of the insert lid should preferably be always close to an annular area of the inner surface of the can jacket issue.

The task is solved by realizing the generic features together with the characterizing features of claim 1.

Preferred embodiments are characterized by features of the dependent claims.

In solving the task, it was particularly recognized that the contact area can be pressed against the inside of the can jacket and therefore not inserted state are formed little larger than the can opening should. When inserting the lid into the box, the largest circumferential line should appear of the contact area through an elastic deformation of the end surface adjust to the inside of the can jacket. So that the Plugging forces from the can jacket into an irreversible one Lead to deformation, the end face must be radial to the contact area spring properties have an elastic deformation of the contact area enable in the radial direction. To ensure these spring properties the end surface has a deviating from a flat surface Shape up. When inserting the cover, this deviation is due to the pressing together of the contact area somewhat increased, which leads to restoring forces leads the contact area against the inside of the can jacket press. The shape stamped on the end surface ensures that when inserting the lid there are no wrinkles or other irreversible deformations arise. This also results in a major improvement the stiffness or the resistance to the twisting of the Cover.

If the end surface is only dome-shaped - with the highest point in the Area of the center of the end face - is trained, so go for it only small restoring forces because the radii of curvature of the cathedral change little when inserting the cover. With small requirements the tightness of the can closure is sufficient for such a dome-shaped configuration the end surface. Waves, especially concentric waves that are embossed along the contact area in the end face closer to the contact area and experience even with small radial movements of the contact area are sufficiently large relative changes in shape to accommodate spring forces effect in a higher size range. Under waves should all possible - essentially with a constant distance to the contact surface trending - indentations or indentations or grooves in the end surface be understood. These waves preferably extend along a closed line. Embodiments are also possible, however which the individual waves only along sections of a closed Line are pronounced.

Lids produced according to the invention can be used for cans with circular openings as well as for cans with differently shaped openings, especially for Rectangular or hexagonal openings, especially with rounded ones Corner areas. With circular can openings and Correspondingly shaped contact areas, the waves are also preferred circular and arranged concentrically. In contact areas the preferred ones are with circumferential lines approximated to polygons Waves in a range from polygon to circular lines. Preferred Embodiments achieve the desired spring property the use of two side by side - essentially at constant intervals to the contact area - running waves. Due to the spring action of the end face, or its deviating from a plane Shape, it ensures that the contact area is always tight abuts an annular region of the inner surface of the can jacket. On Another advantage of the spring action generated in this way is that by a age-related flattening of the end surface, or the attached surface Waves, the seal is not reduced but increased.

It would also be conceivable to form a wave in the contact area, which during Inserting the lid would be flattened. The disadvantage of such a wave would be that with a fatigue or age-related flattening of this Wave the sealing effect would be lost.

When manufacturing a plug-in lid according to the invention, first in one Stamping and pressing process the end surface with one facing outwards standing - preferably still slightly conical to the outside - Cut out edge area; in particular, the marginal area becomes education the contact area is conical or, if necessary, already cylindrically formed; by pressing or embossing, the end surface is turned into one of one Placed a different shape. Then the final area passed through a cardboard cylinder section that sits on a die, whose hole diameter is about the inside diameter of the cardboard cylinder section corresponds until only the uppermost part of the contact area bears against the inside of the lower area of the cardboard cylinder section and can be associated with it. To connect the Cardboard cylinder section with the contact area is a heat seal connection, preferably in a manner known per se by means of heatable expansion wedges or the like, but possibly also a glue connection or about one Rolling connection, trained. The disadvantage of using glue is that that glue applied to the points to be joined when performing the end surface are stripped by the cardboard cylinder section can. For sealed and possibly also for glue connections preferably a pressing device with pressing parts that can be pressed outwards used. especially one that gives off heat for heat sealing.

The pressed parts with a convex pressing surface are from a feed position with a smaller one Press surface circumference movable in a press position with a larger circumference. The pressed parts can be dimensioned so that they lie against each other form a paragraph-free, closed circumference.

Further details of the invention will become apparent from the following Description of exemplary embodiments explained in the drawings.

Fig. 1

einen vertikalen Schnitt durch das obere Dosenende und durch den darüber gehaltenen Deckel einer bevorzugten Ausführungsform der Erfindung;

Fig. 2

einen erfindungsgemässen Deckel in einer Ansicht von unten;

Fig. 3

einen vertikalen Schnitt durch das obere Dosenende und den eingesetzten Deckel;

Fig. 4

die Seitenansicht einer Abschlussfläche mit einem kegelförmig nach oben stehenden Kontaktbereich und darunterliegendem Kartonzylinderabschnitt;

Fig. 5

einen vertikalen Schnitt durch den Kartonzylinderabschnitt mit eingesetzter Abschlussfläche;

Fig. 6

Ausschnitte aus vertikalen Schnitten durch eingesetzte Abschlussflächen;

Fig. 7

einen vertikalen Schnitt durch eine Seite des oberen Dosenendes und des darüber gehaltenen Deckels der Standardausführung der Erfindung.

Fig. 8

einen vertikalen Schnitt durch eine Seite des oberen Endes einer Dose mit darüber gehaltenem Boden einer zweiten, darauf zu stapelnden Dose.

Show it:

Fig. 1

a vertical section through the upper end of the can and through the lid held above a preferred embodiment of the invention;

Fig. 2

an inventive lid in a view from below;

Fig. 3

a vertical section through the upper end of the can and the inserted lid;

Fig. 4

the side view of an end surface with a conical upstanding contact area and underlying cardboard cylinder section;

Fig. 5

a vertical section through the cardboard cylinder section with inserted end surface;

Fig. 6

Excerpts from vertical cuts through inserted end faces;

Fig. 7

a vertical section through one side of the upper can end and the lid held above the standard embodiment of the invention.

Fig. 8

a vertical section through one side of the upper end of a can with the bottom of a second can to be stacked on top.

Fig. 1 shows a plug-in lid 1 made of cardboard, semi-cardboard or solid paper for a box 2. The insert lid 1 consists of an end surface 3, which extends over the cross section of a can opening 4 and in its Outside area over a curvature of essentially 90 ° into a contact area 5 passes. At the free or open end of the contact area 5, preferably on a partial area of its outer surface, is a - preferred from an obliquely wound tube, in particular of the same cross section like the can jacket 2 - cardboard cylinder section 6 at least with attached to its first end portion 6a. The first end region 6a has the same Opening cross section like the can 2 which can be closed with the lid 1, so that this first end region 6a when inserting the cover as at the The stop area that can be created can act. The second end area 6b of the cardboard cylinder section 6 is to form a grip rib on the inside folded or rolled. In the illustrated embodiment, the connection is of the contact area 5 with the cardboard cylinder section 6 as a seal connection executed. It would also be possible to use this connection as a rolling connection to train.

In the end face 3 are two circular, concentrically arranged Waves 7, and a central, possibly against the end area with the dome-shaped curvature 8 directed towards the grip rib. However, it can be preferred to close the dome-shaped curvature against the inside of the can judge (not shown), because then when the relatively good sealing lid the curvature by the pressure of the space between the covers and any membrane film (not shown) (or according to its Opening or removal by the consumer through the internal pressure of the can) the pressure on the contact area is increased and / or the curvature upwards knock over. In the exemplary embodiment shown, the two shafts 7 run in the outer edge region of the end face 3, the distance between the outermost ones Wave from the contact area corresponds essentially to the wave width. The waves 7 and the curvature 8 are so pronounced that the contact area 5 directly after the transition from the end face 3 to the contact area 5 little about the opening edge 4 one to be closed Can 2 protrudes. When inserting the cover 1, this protruding area pressed inwards; the waves 7 and the curvature 8 become something increasingly trained and produce - in the sense of a compressed Spring - a restoring force that the contact area against the inside of the can jacket.

Fig. 2 shows the concentric shafts 7, Fig. 3 that when inserted Cover 3 tensioned shafts 7 and the slightly raised curvature 8.

Fig. 4 shows an end surface 3 with a conical contact area 5 at Insert into a cardboard cylinder section 6, Fig. 5 after sealing with the cardboard cylinder section 6. The free end of the cardboard cylinder section is then turned or rolled inwards. The cardboard cylinder section 6 is cut from the same tube as that Can jacket and can be wound spirally or in parallel.

FIG. 6a shows shafts 7a formed upwards, FIG. 6b downwards Shafts 7b, and Fig. 6c a combination of up and down trained shafts 7a and 7b. It goes without saying that the most varied Waveforms and combinations of waves can be used are, provided that they make the desired spring effect achievable.

7 shows the standard embodiment of the invention in a somewhat enlarged representation, with an end surface 3 ', the vertical edge region 5' of a cardboard cylinder section 6 is included, the upper edge for training a grip rib (this in an analogous manner as shown in Fig. 1) is crimped inwards.

8 shows the attachment of a stack bead 6c at the upper edge of the cardboard tube section 6, and the lower one arranged above the can jacket 2 End 2 ', 5 "of a second can to be stacked on top.

Claims (12)

1. Method for manufacturing an inserted lid (1) of board, cardboard or strong paper, for a container (2) of board, cardboard or strong paper, the inserted lid (1) being provided with a closure surface (3) which, at its edge, continues as a cylindrical contact region (5) and has a section (6) which grips around the free or open end of the contact region (5) and, with its outer border (6a), forms a stop region which can be placed against the edge of the container orifice, and the inserted lid (1) being manufactured separately from the container (2), characterized in that the section (6) is cut from the same tube as the sidewall of the container (2), is folded over - preferably rolled - inwards in a manner known per se and forms a grip rib with the inner region (6b) thus formed.
2. Method according to Claim 1, characterized in that the closure surface (3) is formed having a shape differing from a flat surface and thus acts as a spring element for the contact region (5) adjacent to the closure surface (3), which spring element makes it possible to press said contact region against an inner surface of a container sidewall.
3. Method according to Claim 1 or 2, characterized in that the contact region (5) is cylindrical and the closure surface (3) is rotationally symmetrical.
4. Method according to any of the preceding Claims, characterized in that a dome-like curvature (8), preferably towards the interior of the container, is formed in the closure surface (3).
5. Method according to any of the preceding Claims, characterized in that the closure surface (3) comprises at least one corrugation (7) - essentially a constant distance away from the contact region (5).
6. Method according to Claim 5, characterized in that the distance of the outermost corrugation (7) from the contact region (5) is essentially chosen to correspond to the corrugation width and preferably at least one further corrugation (7) is arranged inside the first one, preferably concentrically with it.
7. Method according to any of the preceding Claims, characterized in that the contact region (5), directly after the transition from the closure surface (3), projects beyond the border (4) of the orifice of the container (2).
8. Method according to any of the preceding Claims, characterized in that the closure surface (3) and the contact region (5) are coated with a protective layer, preferably with aluminium or plastic.
9. Method according to any of the preceding Claims, characterized in that a stacking bead (6c) is arranged in the cylindrical board section (6), at its upper edge.
10. Method according to any of the preceding Claims, characterized in that the closure surface (3) with an edge region projecting outwards is cut out in a punching and pressing process and the edge region for forming the contact region (5) is shaped conically or optionally cylindrically, the closure surface (3) being formed, for example by pressing or embossing, into a shape deviating from a planar surface, in particular having a dome (8) and/or having at least one corrugation (7), but preferably having at least two corrugations (7).
11. Method according to Claim 9, characterized in that the closure surface (3) is passed through a cylindrical board section (6) until only a part of the contact region (5) rests on the inside against the cylindrical board section (6) and is joined thereto.
12. Method according to Claim 9 or 10, characterized in that a part of the contact region (5) is joined to the corresponding region of the cylindrical board section (6) using a press apparatus having elements which can be pressed outwards, which press apparatus preferably outputs heat to permit heat sealing.

Images