IE43067B1 - Packagings - Google Patents

Abstract

1514260 Egg cartons P HINTEREGGER 11 Sept 1975 [16 Sept 1974 13 May 1975] 37404/75 Heading B8P [Also in Division B5] A carton, for eggs or fruit, deep drawn from thermoplastics foil has an upper portion 2 hinged at 4 to a lower portion 3 and is provided with undercut latches 7, 8 that engage each other. The latches may be provided at the centre as well as along the edges of the upper and lower portions as shown in Figs. 2 and 3. To facilitate separation of the cartons from a stack prior to filling spacing knobs 35, 351, 3511, Fig. 12 are formed at the corners of each portion the knobs being shaped so that the top dimension b is larger than the bottom dimension a thereby ensuring a gap c.

Description

The invention relates to packagings made from a thermoplastics foil using a deep-drawing die.

Packagings of this type already on the market are provided, for example, with insert cups for accommodating eggs, fruit and the like, in which case there are formed at least at those edges of the two halves of the packaging folded together like a book, which edges are applied one on top of the other upon closing the packaging, hollow projections moulded in one piece with said halves and which, when engaged in one another in pairs, form fastening means.

In known packagings of the type under discussion the projections ehgage in one another in the manner of a pressfastener, in which case they are either undercut in such a way that a satisfactory locking action is made possible or on one half of the packaging, projecting protuberances are formed which each ehgage resillently in a holelike'cavity in a projection on the other half of the packaging in a manner causing friction contact.

The described type of fastening means or closure for packagings has proven to be universally successful but is still in need of improvement. If, for example, a somewhat thicker plastics foil is used, which is necessary in order to be able to produce a package to accommodate 12 eggs, then difficulties arise in the conformation of the fastening means in the course of the deep-drawing of the thermoplastics foil.

Moreover, special automatic machines, designed in accordance with the nature of the press-fastener closure, are necessary for the automatic closing of the packagings after the insertion of the goods, which machines considerably increase - 2 43067 the cost of the packaging process. Furthermore, it would appear to be advantageous to be able to open and close the packaging repeatedly, which is not always possible with the delicate press-fastener closure. The closure should also not spring open by itself, since the packaged goods are mostly of a delicate nature.

Such packagings, consisting of thermoplastics synthetic material, for eggs, fruit and the like are formed by deep-drawing a heated plastics foil and are then stacked onto and inside one another so that they can be despatched compactly. In the course of packing the goods, it is necessary for the individual packagings to be removed separately from a stack, using a device, so as to be forwarded to the packing station. This process, which is termed destacking in the technical terminology, is thus difficult, since the individual packagings tend to cling to one another because of the ueiqht of the stack. This results in interruptions in the packing operation and thus it has to be ensured that the packagings are prevented from clinging to one another.

For this purpose it has already been proposed to make the packagings which per se are identical to one another, dissimilar at separate points, i.e. to provide them with projections or recesses for example, so that in each case two packagings arranged in superimposition are provided at different locations with projections or recesses. However, if by chance it happens that two completely similar packagings come to lie one on top of the other, whereby the abovedescribed drawback occurs, precise destacking by the automatic equipment is not possible.

It has now been found that the problems described above can be satisfactorily solved by way of a device based, in principle, on the same fundamental idea. The device makes possible, on the one hand, the production of particularly effective fastening means which are substantially superior in operation to the previously used so-called press-fastener closure and, on the other hand the device can be used for the production of spacing projections on the packaging, which allow accurate destacking of stacked packagings before the forwarding of each individual packaging to the packing station.

According to the invention a packaging made of deep-drawn plastics foil comprises two halves joined together by a web and having insert cups and hollow projections, moulded in one piece with the two halves, formed at least at those edges of said halves which are applied one on top of the other upon closing the packaging, said projections forming fastening means, when engaged in one another in pairs, and each being of hook-like configuration and having a hollow stem extending away from a half of the packaging and merging into a hollow lug extending approximately perpendicularly thereto, which lug engages, in the closed position, under the corresponding lug of a hollow projection on the other half of the packaging. Preferably, the insert cups are adapted for accomodating eggs, fruit.and the like.

By way of example, specific embodiments of packagings in accordance with the invention will be described with reference to the accompany· ing drawings in which:Figure 1 shows in elevation a packaging according to the invention in the closed position; - 4 43067 Figure 2 is a partial plan view of the packaging according to Figure 1, but in the non-closed position; Figure 3 shows a packaging in section along the line IIIIII in Figure 2 shortly before being closed; Figure 4 is a view in perspective of part of the fastening means of the packaging; Figures 5, 6, 7 and 8, 9, 10 show two embodiments of a tool for producing the fastening means of the packaging, partly in section, in elevation and plan view, respectively; Figures 11 to 15 relate to the design of the spacing projections on a packaging of the above type and to the associated tool .

Figures 1 to 3 illustrate a packaging made of thermo-plastics foil. It is a double packaging for 12 eggs which packaging can be divided into two parts along a dividing or tear-off line 1, if so desired. The packaging comprises two halves, i.e. an upper part 2 and a lower part 3, said halves being interconnected by a type of hinge-like web 4, Accordingly, the packaging is in one piece, i.e. all the parts are formed from the same foil in a single operation in the course of manufacture by deep-drawing a heated plastics foil.

In order to be able to hold the packaging closed after the insertion of the goods, e.g. eggs, as a rule by means of an automatic machine, there are firstly provided as fastening means at the edges 5, 6 opposite the web 4,projections 7 obtained by deep-drawing and which have hook-like configurations. Basically, each projection 7 has a hollow stem 8 which extends away from one half of the packaging and which merges into a lug 9 extending approximately perpendicularly away therefrom. This lug 9 engages, in the 007 closed position of the packaging, under a similar lug 9 of a hollow stem 8 or a projection on the other half of the packaging, which interengagement of the projections is sufficient to keep the packaging closed. The packaging can then be opened merely by sdight deformation.

Such projections 7 are nothowever, only provided at the edges of the packaging but also in the centre thereof, as may be seen from Figure 2. Advantageously, at least two hollow projections 7 with their lugs 9 arranged so that they extend in opposite directions with respect to one another, are provided on one and the same half of the packaging, whereby the projections afford a further protection against accidental opening of the packaging. This type of arrangement of the fastening means constitutes a type of cross-locking, wherein the projections at the edges prevent accidental disengagement of the projections provided in the centre of the packaging.

The design of the fastening means may be different from that described above, for example they may be as illustrated in Figure 4. It will be appreciated from Figures 2 and 4 that there is located in the centre of four cups 10 of the packaging a square spacing abutment 11 whose height depends on the height of the web 4 joining the halves of the packaging. From each abutment 1l there projects upwardly a hollow stem 8. At its top end said stem merges into a lug 9 extending approximately perpendicular thereto and which forms, together with the stem 8, a hollow locking hook. Step-like side parts 12 are provided on the hollow stem 8, whereby a further locking action is obtained in the event of interengagement of the fastening means.

Figures 5 to 10 illustrate the essential parts of the tool for the production of the fastening means of the packaging shown in Figures 1 to 4.

In Figures 5 and 6 a tool shank made of brass is designated 13, which is used in a conventional deep-drawing die for the production of egg packagings at a point at which a projection 7 is to be formed. This shank 13 has at its thickened top part 14 a tapered shank head 15 which has a slot-type recess 16 for the mounting of a core 18 in the form of a pawl by means of a pivot 17.

At its upper end the core 18 has a lug 19 which extends laterally away from the actual core in hook-like manner.

Opposite this lug 19 the core 18 is provided with an extension 19' which tapers downwardly. On the inner oblique surface of this extension a spring 20 is located in a groove 18', this spring maintaining the core 18 in its normal posi tion.

A recess 21 extends so far into the interior of the shank 13 that the extension 19' can swing inwardly by about 45°.

In this inwardly pivoted position the pointed lug 19 is pivoted upwardly about the pivot 17 to such an extent that it does not represent any obstruction upon removal of the packaging.

During the deep-drawing process the plastics foil, which is preheated to above 100°C, is applied flush against the surfaces presented by the deep-drawing die, thus also against the shank 13 together with the front edges 22 and core 18 with its lug 19, this latter forming an undercut.

If the core 18 were not pivotably mounted, then the packaging formed could not be removed from the deep-drawing die. The resilient mounting of the core 18 enables the lug 19 to swing upwards and, consequently, trouble-free removal of the formed packaging from the deep-drawing die. It is to be understood that the described tool components 13 to 22 form fastening means of the type illustrated in Figure 4, in the course of deep-drawing the foil.

In Figures 8 to 10 there is illustrated a shank 23 together t with core 28 similar to that in Figures 5 to 7, a hollow projection on the packaging being formed thereby in the course of deep-drawing, which projection co-operates with the projection formed by the shank 13, as fastening means.

The difference merely lies in the fact that there are formed at the thickened top part 24 of the shank 23 two lateral lugs 33 which are at such a distance apart that they laterally enclose the top part 14 of the shank 13. Furthermore, there are also evident in this tool, on the shank 23,the thickened top part 24sa tapered shank head 25 and a recess 26 forthecore 28 which is pivotable about a pivot 27 against the action of a spring 30.

In existing packagings projections were provided in the corners ensuring a spacing apart of the edges. The packagings illustrated in Figures 11 and 12 have spacing knobs 35, ', 35, which each have an undercut 37 preventing packagings from clinging to one another during the stacking together of empty packagings not yet filled with goods.

The internal widths of such a spacing knob 35 (Figure 12) is, viewed from the bottom, less than the external width b of the top surface of the spacing knob, viewed from the opposite side. This prevents any possibility of the spacing knob 35' of a packaging, 2, 3 situated underneath penetrating into the cavity of the similar spacing knob 35 of the packaging situated thereabove in each case, whereby a distance apart c of the packagings stacked inside one another is ensured, corresponding to the height of these projections. Accordingly, no difficulties arise during destacking of the individual packagings in gripping under the edges of the uppermost packaging with gripper members and removing said packaging from the stack.

Of course, the aforementioned undercut projections or spacing knobs 35 still have the existing function of spacing apart the two halves 2, 3 of the packaging in the closed position of the packaging. To this end (see Figure 1), upon closing the packaging, associated spacing knobs 35 rest one on the other, the combined height of the knobs corresponding to the distance apart of the edges of the halves of the packaging determined by the fastening means or the height of the web 4.

The provision of the undercut spacing knobs makes it possible for completely identical packagings to be stacked one inside the other, whilst maintaining a distance apart, without them clinging to one another as a result of the weight of the stack. Therefore, only a single die is required for the manufacture of the packagings.

The forming die for -the spacing knobs of the packaging comprises a cylindrical stud or shank 41 which is inserted in the bottom die 38 of the deep-drawing mould, 38, 39 and has a pivotable lug or pawl 44 at its upper end. The shank 41 is provided with a slot 42, in which the lug 44 is pivotably mounted by means of a pivot 43. A spring 49 engages at one end against the lower extension 48 of the lug 44 and with its other arm passes through a hole in the shank 41. In this way the spring restores the lug - 9 67 into its starting position, upon withdrawal of the tool from the formed packaging-. Trouble-free withdrawal of the lug is made possible in that the projecting lower edge 46 of the lug 44, 45 aligns with the contour 47 of the shank 41 (Figure T5) after pivoting.

The production of the packaging takes place in conventional manner by deep-drawing a heated plastics foil F using a mould 38, 39, the air being exhausted through the aperture 40 so as to causA the foil to be applied against the mould faces. Forming dies as described above are disposed in the corners of this mould, in such a way that they turned through 45° in relation to the edges of the packaging.

The undercut spacing knobs can, of course, have any other cross-sectional shape since, in principle, this is not a vital point. Rather, it is essential that the spacing knobs have such a shape that any pentration of the spacing knobs into one another is prevented during stacking under the pressure of the weight of the packagings themselves, thereby preventing two packagings stacked one inside the other, clinging together.

Claims (6)

1. Packaging made of deep-drawn plastics foil comprising two halves joined together by a web and having insert cups and hollow projections, moulded in one piece with the two halves, 5 formed at least at those edges of said halves which are applied one on top of the other upon closing the packaging, said projections forming fastening means, when engaged in one another in pairs, and each being of hook-like configuration and having a hollow stem extending away from a half of the lo packaging and merging into a hollow lug extending approximately perpendicularly thereto, which lug engages, in the closed position, under the corresponding lug of a hollow projection on the other half of the packaging.

2. Packaging according to claim 1 wherein the insert cups 15 are adapted for accommodating eggs, fruit and the like.

3. Packaging according to claims 1 or 2, wherein at least two hollow projections are provided on one and the same half of the packaging, the lugs of the projections extending in opposite directions with respect to one another. 2

4. Packaging according to any of the preceding claims wherein the hollow projections forming the fastening means project from spacing abutments, the lug of one hollow projection abutting a corresponding spacing abutment to space the halves of the packaging apart, a distance corresponding 25 to a spacing formed by the web.

5. Packaging according to any one of the preceding claims, including spacing knobs, of which associated knobs upon closing of the packaging abut each other to space the halves of the packaging apart, a distance corresponding to a spacing formed by the web, and at least one portion of each spacing knob being of under-cut configuration so that inter-engagement of two knobs is prevented during the stacking of empty packagings one into another.

6. Packaging substantially as herein before described with reference to and as shown in figs. 1 to 4 and figs. 11 and 12