Foldable container with gusset folds

The invention relates to a container especially for fluids, folded up from a sheet, which is carved from e.g. cardboard or plastic foil, without the parts of the sheet previously being glued together. The invention also relates to a procedure and an apparatus for producing, filling and possibly closing of the container.

The use of the container according to the invention is especially for contents of products containing water and for fluids, which naturally takes it for granted, that the material of the container is sufficiently tight. But the container can also be used for e.g. powders and various goods, whereby the folding lines, after which the parts of the sheet are folded, either totally or partly can be replaced by perforations in the material. The most important use is yet for totally tight containers, e.g. open cups and deep plates, which by simple means are kept in an upright position. Hereby the container also can be filled and closed by means of machinery, standing and conveyed separately and stable on its flat bottom. The invention therefor also relates to closed containers for fluids, plus a procedure and an apparatus, which from the flat sheet and untouched of people, produces, fills and probably also conveys and closes the container.

There is known quite a few containers suited for being folded up to e.g. a ready box from the flat sheet, without the parts of the sheet, as usually is the case, at first are glued together with a hot melt glue, as their sides are connected through side flaps. There are known containers too, which can be kept in their upright position by means of co-operating slits and taps in the material. From US patent No. 5,086,971, Detzel et al, there is known a container, from where the four corners of its quadratic bottom are folded up to four sets of gussets or flaps, where each is equipped with a tap, which fits into slits on two opposite sides. Something similar is known, e.g. from US Patent No. 5,853,121, L.H. Fransisco and from DE 89042786, A. Oetker, where a tap from one or both parts of the flaps is put into the nearest positioned slit in two opposite positioned sides. The disadvantage is here, that it needs contact and closing in a total of four areas on the side- walls of the container.

This disadvantage is sought limited in e.g. DE 9406206, H. Hauck et al, where the container only have a single slit in the middle of the two opposite side- walls, where the taps from the two nearest placed set of flaps shall be fitted in. In US Patent No. 2,341,762, A.R. Conklin, the number of areas, which are to be connected, is sought limited by having taps on two sets of the flaps and matching slides on two other sets of flaps. Yet both types of solutions need, that although there only are two areas, where the taps and the slits shall be fitted in together, more than one single time-consuming adjustment shall happen at each of the two opposite sides, where both the nearest sets of flaps are kept in position.

The new technical means for containers according to the invention will result in an improved container, which in the future most simple, both mechanical and manually, can be folded from a flat sheet to a self-supporting, open cup or a filled and closed container. This is obtained especially by it alone is the set of flaps, which by the folding is placed most far away from the side- wall, whereto the two nearest set of flaps are to be fixed, that are active by the fixation. The set of flaps, which is positioned closest to the side, therefore neither needs any extensions nor openings, as these flaps alone is fixed by the on their outer side placed set of flaps. This uttermost set of flaps advantageously can be equipped with an extension or a tap, which fits into a single opening or slit in the side- wall, whereto both set of flaps are kept fixed. These two opposite side- walls are also advantageously made higher, especially if the container shall contain a fluid, so the opening can be placed so high in relation to the other side- walls of the container, that it can contain the largest volume of fluid. The higher side- walls also result in, that you thereon can place and design the opening so advantageously, that an extension from the most far away from the side-wall placed set of folded flaps quickest and most simple can be pressed there into, manually and by machinery as well.

The technical effect from the mentioned means are, both from the manual and from the by machinery made up-folding from the sheet, that the stable keeping in the upright position, the filling and possibly also a closing of the filled container, can be made to happen extremely simple and effective. This especially because the container according to the invention only needs, that there is made contact between opening and tap two times, one time on each of the

two opposite side-walls, while the above-mentioned known containers of this type needs at least twice the number of contacts. Thus time is saved and most easy achieved, that the single container can stand freely and stable on its flat bottom during filling and during a possible conveying further for closing. By the container being folded up from a thin and flat sheet, which for the fluid contents is or can be made fluid-tight, and which until, and possible even during closing has no need for external means to keep the single parts of the sheet assembled, you obtain as mentioned further advantages. As these can be rather various, amongst others depending of the size, the use and the design of the container, the further technical effects and the connected advantages are for practical reasons nearer described underneath with reference to the relevant figures on the drawing, where

fig. 1 shows a design according to the invention of a sheet for folding up seen from above, fig. 2 the same design seen in perspective of a sheet folded up as a container, fig. 3 a similar design seen in perspective squeezed together at the top for closing, fig. 4 a design according to the invention of a sheet for sloping side-walls seen from above, fig. 5 the same design seen in perspective folded up as a container, fig. 6 another design seen in perspective folded up as a container, and fig. 7 the same design with the plane sheet seen from above before being folded up.

On fig. 1 is seen a simple design of a coming container according to the invention in the plane state. Here it consists of a carved sheet of a thin, stiff and watertight cardboard, which on its middle has, what is to become a flat, quadratic bottom 2. The bottom is limited by bending- or folding lines 3, which continue in other folding lines 3 ^' which limit, what after the folding will become the side- walls 4 and 4 ^' . Between the folding lines 3 ^' extend from each of the four corners of the bottom slanting folding lines 5, which form an angle of 45 degrees with the sides of the bottom 2. They also part the four rectangular areas uttermost against the corners of the sheet into two parts, each with a circumference as a right-angled and an even-legged triangle, which here is named as a set of coherent flaps 6 and 6 ^' . From one of the parts on the flaps 6', and here both of them turned upwards on the sheet 1, there is an extension or a tap 7, designed so it fits into an opening or a slit 8 on each its side- wall 4'. The two other side- walls

4 on the other hand neither have taps nor other extensions. The between each set of flaps existing sloping folding lines 5 cause, that the side-walls 4 and 4' can be folded up until a position, up against or as here into a right angle to the bottom 2, as it will appear from the next figure. If the container does not need to be watertight, some of the folding lines possibly can be substituted by perforations, so you can achieve sharper folds and thus a nicer look. If the container on the other hand shall contain a fluid, a sheet of e.g. a relatively cheap form of cardboard only needs a preceding layer of lacquer or a laminating on the inside for sealing. If the used container is to be cleaned or maybe even reused, the container easily can be reopened and folded out, so that the sheet possibly can be flushed and dried. On the backside of the flat sheet there suitably and cheaply can be printed use instructions, pictures and advertisements, so that the sheet even can be delivered at no costs as an advertisement gift.

Fig. 2 shows in perspective the same sheet 1 folded up to a fluid-tight container, where the side- walls 4 and 4' are erected upright. The four set of flaps 6 and 6 ^' hereby are squeezed tightly together around each its sloping folding line 5, here on the outside of the side- walls 4'. These are preferably taller than the side-walls 4, so that the opening, here the slit 8, is being positioned above the mutual "waterline". The two taps 7 are seen to be situated in a suitable distance against the peak of their flaps 6 ^' , to obtain the tightest contact with the belonging side-wall 4 ^' . It is this set of flaps 6', which shall be placed uttermost to obtain a good fixing against the side 4 ^' , both of itself and of the other set of flaps 6. This innermost set of flaps 6 therefor is not equipped with active means of connection as extensions or openings. But the set though in principle can be thought to have passive incisions in the form of a sort of cuts or undercuts for further securing of the fixation. By a passive incision there is here understood, that it in opposition to the active taps 7 has no need for an adaptation into a slit 8 for being useful. It shall be noticed, that the taps 7, and thereby also the slits 8 on the side-walls 4', are displaced over the middle-point against the same side-wall 4. This will make the container more harmonic and easier to close, simplify the apparatus for the mechanical filling, and it will also serve as the most self-instructing, plus give the best utilization of the space on the sheet 1 , compare with fig. 1.

On fig. 3 is seen in perspective a similar filled container of e.g. a thin plastic foil, which is ready to be welded fluid-tight together at the top, after first being squeezed together at the top around the folding lines 9 on the side-walls 4. The container thereby will obtain a pair of peaks turned outwards, which easily can be cut or torn off, so that a good pouring spout is obtained. In comparison with a shape as e.g. a gable-top, known from cartons for milk, it also has the advantage, that the container thereby can contain a bit more. In comparison to the for several sorts of fluids used packages in the shape of a pillow of thin plastic foil, the container according to the invention stands considerable more stable on its quadratic and flat bottom. The material of the container consequently can come from an especially thin plastic foil or from a cardboard suited for welding, like e.g. cartons for milk or juice. But in opposition to these, which demand big and complicated plants, that can shape the material as a tube before the filling and closing, this now can be realized from previously carved sheets or from small rollers of material in a relatively simple, preferably small and semi-automatic, maybe even mobile apparatus. The apparatus can preferably be totally mechanic, as a stable and lasting up-folding from the flat sheet can happen easily and without the need for neither compressed air nor vacuum, thanks to the simple method for up-folding and fixing of the single-standing containers in the upright position.

Fig. 4 shows a sheet 1, which shall become a container with sloping sides, e.g. a bowl for salads or a tray for berries. In comparison to the container in the previous figures, which especially are suited to be closed at the top with a welding or with a tape, this design is particularly suited for open containers. The sloping side-walls also are an advantage, if the containers are to be piled up immediate after their production. Contrary to fig.l, there here is seen to be extensions in the form of taps 7 on both sides of the set of flaps 6', which shall be squeezed into the slit 8, which can be an advantage by certain thickness and types of material, especially by the manual closing. The opening in the elevated side- wall 4 ^' , the here specially designed slit 8, is placed in such a way, that the part of the slit which comes into contact with the taps 7, slopes upwards in the same direction as the top of the folded flaps 6. The part of the slit 8, which is closest to the middle point of the side 4', is just like the corresponding part of the taps 7, that is closest to the middle line, suitably very close hereon. Thus will in this

cross-field be obtained a surprisingly strong an durable connection with the smallest possible overlap between the tap and the slit, where the innermost set of flaps 6 especially is fixed extra fine, compare also with the following figure.

On fig. 5 is shown in perspective the same shape folded up to the final container. It is seen, that the cross-field between the two set of flaps, 6 and 6', which is situated in the middle line of the side- wall 4', is caused in a natural way as a result of the sloping folding lines 3 ', that was shown in the preceding figure. This causes, that both set of flaps are squeezed unusual strongly together with the side- wall 4', even with a relatively small interaction between the tap and the slit, and that especially the passive set of flaps 6 is kept even better on its place. Also you in this way will be able to ease and simplify the cohesion, both in a manual and in a mechanical way.

Fig. 6 shows in perspective a container according to the invention folded up from the sheet 1 , that is shown in the following figure. The two figures demonstrate, that you can achieve the effective sloping cross-field also for containers with upright side-walls. The shown design of the slit 8 is largely as in the previous figure. A broader slit, that is with a wider opening, so that the upwards turned area inside the slit becomes more freely movable, can possibly be an advantage by easing the closing. The nearer shape hereof will yet especially depend of the material of the container and of its thickness.

On fig. 7 is seen from above a sheet 1, which when it is folded up will become the container, that is shown in the preceding figure. To obtain the above-mentioned effective cross-field even with folding lines 3', which are not sloping, are especially the passive sets of the flaps 6 prolonged away from the here rectangular bottom 2. The two active set of flaps 6', that both on the figure are placed at the right, are advantageously a bit shortened and rounded. Here are shown extensions on both parts of the flaps 6', but depending of the material of the sheet etc. there only needs to be a tap 7 on that part, which by the up-folding will be situated most far away from the side- wall 4'. On the other figures the bottom 2 has been shown quadratic; but as it here will appear the bottom very well can be rectangular and so oblong, as you may wish,

as the closing mechanism is not depending of the length of the container. Like it is being suggested at the left on the figure, there advantageously in elongation of the side-wall 4 can be formed a lid for the container. There may even on both side-walls 4 be extensions, which can be formed as lids and/or carrying handles for the container according to the invention.

There could on the drawing have been shown several and other figures. E.g. designs with different types of corresponding extensions and slits, designs with openings for handles situated at the top of the elevated side-walls 4', designs with lids and/or carrying handles in extension of especially the side- walls 4, plus flow-sheets for the demonstration of the particular simple apparatus for mechanically to produce, fill and possibly also close the containers according to the invention. The shown examples yet should be sufficient to give an expression of the many possibilities of the invention, which in spite of the fact that this in the principle very simple design of the containers opens up for research and development on a long trail of different areas, from the deep plate to new shapes of practical and tight containers in especially smaller number of pieces, plus for the apparatus for their production.