WO1984000736A1

WO1984000736A1 - Method for manufacturing boxes, especially for transporting bottles, and a box manufactured according to the method

Info

Publication number: WO1984000736A1
Application number: PCT/DK1983/000077
Authority: WO
Inventors: Bjarne Bo Andersen; John Franklin Christensen
Original assignee: Cerekem Danish Food Tech
Priority date: 1982-08-18
Filing date: 1983-08-18
Publication date: 1984-03-01
Also published as: OA07414A; EP0116607A1; DK369382A

Abstract

According to a method of manufacturing boxes, especially boxes for beer and mineral, of plastic by insertion and compression, the box is cast in extended condition in a multi-daylight tool with the side and end parts (1, 2) connected to the bottom (3) by connecting links (7, 8) provided with weakenings so as to serve as hinges for the side and end parts. These can consequently be folded and led over and support against a raised edge of the bottom along the periphery of same, after which they are welded or riveted. This makes it possible to manufacture tall bottle boxes without any of the problems connected to the traditional use of jaw tools, and at the same time a smaller volume and a considerable saving of plast mass is obtained.

Description

Method for manufacturing boxes, especially for transporting bottles, and a box manufactured according to the method

The present invention relates to a method for manufacturing boxes, especially for transporting bottles. For long boxes for transporting beer and mineral bottled in the usual bottles of 3/8 litre have been made of impact- proof plastic, whereas beverages bottled in larger bottles of 3/4 litre are usually transported in cardboard boxes. These boxes cannot withstand strong mechanical forces and cannot be used again. Consequently they cannot be used for returning the empty bottles, if required. Therefore, for some time boxes of plastic have been manufactured, intended for larger bottles than the usual beer bottles, but otherwise of a construction similar to that of the known beer boxes.

These known beer boxes are cast in one piece in a jaw tool, which means that the moulds defining the outside structure of the box are "jaws", which can be moved perpendicularly to the cast box, whereas the inside structure is defined by a core which is drawn up when the casting is finished and the box is cooled sufficiently to keep its shape. This casting method is comparatively free of problems when manufacturing boxes for bottles of 3/8 litre, but there are considerable drawbacks when making the boxes so tall that they can be used for larger bottles

As is the case with all other casting methods, the moulds or matrices must have a draw which as for the core must be larger, the taller the box is. As the top of the box must have a thickness of plastic offering the necessary ultimate strength, the thickness of the bottom must be larger than necessisated by the ultimate strength to obtain the necessary draw angle. Inside ribs must be reduced to a minimum and must necessarily be vertical, otherwise the core cannot be drawn up, which means that only ribs serving as attachments for supporting ribs inserted later on should be placed inside and must start from the bottom where they must also be thicker and broader than at the top to let the core be released. The supporting ribs necessary to keep the weight of the box to a minimum must therefore be placed on the outside, where, as mentioned, the mould parts are jaws which can be drawn away from the finished box.

Another problem which is not especially connected to the manufacture of tall boxes but to casting in jaw tool in general, is a fast cooling of the cast object. The cooling takes place by means of the jaws and core being provided with ducts for cool am. In places where two or three surfaces meet in an edge or a corner, the core is receiving a larger amount of neat than elsewhere, resulting in a slower cooling.

All these manufacturing problems make the known boxes for bottles of 3/4 litre considerably heavy and fill up approx. 15% more than a corresponding cardboard box.

The invention departs from the traditional conception that it is an economical necessity to manufacture boxes in one single process - that it is necessary to cast the boxes in a jaw tool - the invention indicating a method which makes the use of multi-dayl ight tools possible, i.e. an injection and compression tool where the moulds are placed above each other in "storeys" forming cavities which correspond to the shape of the object to be produced The most obvious idea would be to produce the bottom, side and end parts separately and then rivet or weld them, but this would be so time-consuming owing to the necessary temporary assembly of the individual parts during the riveting or welding, removal of same and possible reinforcements, that the usual casting in jaw tool would be preferable.

According to the invention the box is injected and compressed in expanded condition in a multi-daylight tool with side and end parts connected to the bottom by flaps which are weakened so as to serve as hinges so that when folded the side and end parts are led over and support against a raised edge of the bottom along the periphery of same.

For reasons of strength it is essential that the side and end parts are placed on a reinforced edge of the bottom and not merely are bent towards this when folded. By this an absorption of compressive strains on the bottom and/or side and end parts as shearing forces on weldings or rivets is avoided. So, besides holding the parts of the box together to avoid five loose parts to be hold together during the riveting or the welding, the hinges define the axis around which the side and end parts are swung over the raised edge of the bottom so as to be kept against this. At the same time they must be strong enough to withstand rough handling. This can be obtained by the hinges being created by cutouts along the edge of the bottom so that only a narrow strip remains, which in the middle is provided with a connection link to the side or end parts. During the folding the narrow strips will be turned 90º on their axis, which will consequently also be the axis of oscillation of the side and end parts.

If the box is to be used for transporting heavy objects as e.g. filled bottles, the tensile strength between the bottom and sides can be increased by providing the side and end parts along the bottom edge with a number of short ribs and the bottom with a corresponding number of short ribs in which longish holes are milled so that during the folding the ribs of the side and end parts are pressed into these holes.

The assembling and riveting or welding of the side and end parts can be made rapidly and conveniently when the end or side parts are shaped with a broad bent edge which during the folding catches around the side parts or the end parts respectively and retains them. The uttermost brims of the side parts can be offset in a width and depth corresponding to the width and thickness of the bent edge of the end parts so that after the riveting or the welding the edges are flush with the outer surface of the side parts.

The method according to the invention leaves it to the constructor to place the supporting ribs, the only demand on same being that they must not be undercut so that the mould cannot be released. A considerably smaller amount of plastic is used for the method according to the invent ion compared to the conventional method, and the time spent on the simple assembling process is recovered by the faster cooling which is possible when using multi-daylight tools. A further advantage of using multi-daylight tools made possible by the invention is that two boxes can be cast at a time.

The invention also relates to a box manufactured by the method according to the invention, but not in a conventional manner. The special construction details which make it possible to reduce the outside dimensions by approx. 15% and to provide the box with plane outer surfaces without protrusions of any kind will appear from the following detailed description of an embodiment of the invention with reference to the drawing in which Fig. 1 shows the finished box in expanded condition,

Fig. 2 shows part of fig. 1 on enlarged scale,

Fig. 3 shows a section through a side part by line I I I - I I I of fig. 2,

Fig. 4 shows a corner of the folded and welded box from above, and

Fig. 5 shows a side and sectional view of the same corner of the box at the bottom.

As shown in fig. 1 the box is cast in expanded condition, consisting of two side parts 1, two end parts 2, and a bottom part 3. As it appears more clearly from figs. 2 and 5, along the brim the bottom is provided with a raised edge 4 serving as supporting edge for the end parts and side parts when folded. As shown in figs. 2 and 4, along both sides the end parts are provided with a flap 4 which encloses the side parts 1 after the folding. As it will appear most clearly from fig. 3 showing the profile of the side parts, these are offset along the side edges in a width and depth 5 corresponding to the width and thickness of the flaps 4 so that after the folding and welding the box appears with smooth outer surfaces. Several boxes can therefore be placed close together during storage or transport.

Side parts, end parts and bottom are cast as a connected whole, the side parts and end parts being fixed to the bottom by means of hinges 6, fig. 1. As shown in fig. 2, these hinges consist of short thin bars resulting from cutouts 8 in tne edge of the bottom, and flaps 9 extending from the bottom edge of the side and end parts. As it will appear from fig. 5, this construction of the hinges effects that during the folding the side and end parts are swung over the raised edge 4 of the bottom part and will stand on this. The connection between the bottom and the side and end parts is further reinforced by the ribs 10 and 11. The ribs 11, which are made in one piece with the bottom, are provided with a longish hole through which the ribs 10, which are made in one piece with the side and end parts, are pressed during the folding, as it will appear from fig. 5.

In order to save plast material and to reduce the weight, the bottom of the box is shaped in the usual way as a network of broad bands provided with supporting fins 12. Contrary to the usual construction of boxes for bottles, no supporting ribs extending from the bottom to about the middle of the box are used, but an intermediate piece 13, fig. 5, with supporting fins corresponding to the fins 12 of the bottom. This construction is made possible by the special method according to the invention, the intermediate piece 13 being inserted between horizontal pairs of ribs 14 made in the side parts. The end parts may be provided with supporting ribs 15, fig. 1, for the vertical fins of the intermediate piece 13.

As shown in fig. 4, according to the invented method brim reinforcements 16 and 17 directed inwards can be made. The brim reinforcement of the end parts are provided with cutouts 18 and 19 so that bottles can be inserted and removed without impediments.

The box is provided with the usual holes 20 in the side and end parts for carrying the box, but contrary to the known boxes, the brim reinforcements 21, fig. 2, are made on the inside just as all the other reinforcements, of which only the ribs 22 are shown, are made on the inside

Of course, the invention can be used for manufacturing boxes of every dimension, but as mentioned in the general description of the invention, it is intended for manufacturing boxes with tall sides and ends. According to the construction described, which is not practically possible without applying the invention, it has e.g. been possible to manufacture a box for bottles of 3/4 litre, the volume of which is 15% smaller than that of known boxes for this purpose, and with a saving of plast mass of approx. 40%.

Claims

1. Method for manufacturing a box of plastic by injection and compression, c h a r a c t e r i z e d i n, that the box is cast in extended condition in a multi-daylight tool with the side and end parts connected to the bottom by connecting links provided with weakenings so as to serve as hinges for the side and end parts so that these can be folded and led over and support against a raised edge of the bottom along the periphery of same, after which they are welded or riveted.

2. Method according to claim 1, c h a r a c t e r i z e d i n, that the fringes have resulted from cutouts along the edge of the bottom so that only thin bars remain, which in the middle are provided with a connecting link to the side or end parts.

3. Method according to claim 1, c h a r a c t e r i z e d i n, that along the bottom edge the side and end parts are provided with a number of short ribs, and that along the brim the bottom is provided with a corresponding number of ribs provided with longish holes so that the ribs of the side and end parts are pressed through these holes during the folding.

4. Method according to claim 1, c h a r a c t e r i z e d i n, that either the end parts or the side parts are shaped with a broad bent edge which encloses the side parts or the end parts respectively after the folding.

5. Method according to claim 4, c h a r a c t e r i z e d i n, that the side or end parts are offset along the edges which after the folding are enclosed by the flaps of the end edges or side edges respectively in a width and depth corresponding to the width and thickness of the flaps.

6. Box manufactured by the method according to claim 1, c h a r a c t e r i z e d i n, that all reinforcing ribs are placed on the inner side of the box, and that all edge reinforcements for both carrying holes and the upper edge of the box are extending inwards towards the middle.

7. Box according to claim 6, c h a r a c t e r i z e d i n, that the bottom consists of longitudinal and transversal strips forming a square network which, except from the brim strips, are provided with vertical supporting fins, and that at least two opposite sides are provided with horizontal double ribs, in the intervening space between which protruding flanges of an intermediate piece con isting of supporting fins corresponding to the supporting fins of the bottom are inserted.

8. Box according to claim 7, c h a r a c t e r i z e d i n, that the horizontal reinforcing ribs and edge reinforcements are provided with circular cutouts of a radius a little larger than that of the bottles and placed in such a way as to let the bottles be inserted in and removed from the box freely.