Background of the invention Fragile articles, such as heavier capital goods for example, are often subjected to careless treatment that may damage the articles prior to its delivery to the end consumer. In order to minimise the risk for this type of damages, the goods are packed in packaging units that are able to withstand the loads and impact forces arising during trans- portation.

The impact-damping packing material typically includes se- veral loose cushions of suitable material arranged between the article and the enclosing packaging container, such as a cardboard box or con- tainer or some other type of enclosing unit. For this type of fragile artic- les, such as microwave ovens or other electrical domestic appliances for example, impact-damping fillers or cushions of injection moulded cellu- lar plastics typically are being used.

This type of articles, i. e. consumer products, are manufactu- red and packaged in large quantities, requiring machine equipment for the erection and forming of the packaging units. Typically, the auto- mated packaging of the articles is carried out in several steps, the first step being the automated erection of the enclosing paperboard packa- ging unit, the second step being the insertion of a bottom filler of cellu- lar plastic in the unit, the third step being the insertion of the fragile article into the erected packaging unit, a fourth step being the insertion of a top filler of cellular plastic on the article and the final step being the

sealing of the packaging unit. In most cases, this packaging. technique requires that the shape of the cellular plastic fillers shall be adapted to the shape of the packaging unit in order to guide the fillers to an accu- rate position in the packaging unit in the automated erection and for- ming process. As a consequence, the volume of the cellular plastic fillers is considerably bigger than would have been required if the sole require- ment of the fillers would be to serve as an impact-resistant element for the packaged articles.

A drawback with the above described packaging technique is thus the big volume of the large quantities of moulded cellular plastic fillers or cushions that are required, leading to high transportation costs as well as storing and logistic problems. The packaged articles, such as electric domestic appliances having a high degree of surface fineness and having surfaces sensitive to surface abrasion, such as glass surfaces, for example, tend to wear during transportation and handling when the packaging units are subjected to rough treatment.

Basic idea of the invention The object of the present invention is to solve the above men- tioned problems by providing a method of packaging fragile articles, a packaging unit blank and a packaging unit for which a simplified auto- mated packaging technique may be used, which require a smaller volume of protective, impact-damping material, which minimise the risk for surface abrasion on the articles and fulfil the requirements of impact-damping.

This object is achieved in accordance with the invention by the characterising features as defined in the appended claims and as will be explained more in detail below.

In accordance with the invention, a flat packaging unit blank, in an automated process, is provided with impact-damping ele- ments which are attached to the panels of the flat blank. The packaging unit blank and the impact-damping elements thus form a flat unit on

which the article is placed. In a subsequent step, the packaging unit blank is erected, formed and sealed around the article in a simple auto- mated fashion. The packaging process is hereby improved considerably.

In addition, the shape and the material of the impact-resistant elements may be fully adapted to the specific impact-damping requirements of the article and it is also possible to use different impact-resistant mate- rials in different positions on one packaging unit blank. In accordance with the invention, the impact-damping elements may be efficiently shaped and positioned, such that the elements are positioned where they have a maximum of impact-damping efficiency and where the article needs to be to be protected the most.

By using the packaging method according to the invention, the volume of the impact-resistant material used in one packaging unit decreases to about 10% of the volume which is required in a conven- tional packaging method as described above. This decrease in volume of the impact-resistant material, also leads to a considerable decrease in transportation and storage volume and simplifies the logistic when large quantities of articles are manufactured and packaged.

Short description of the drawings The invention will now be described in more detail with refe- rence to the enclosed drawings, in which an exemplifying embodiment of the invention is schematically shown.

Figure 1 shows an embodiment of a flat packaging unit blank according to the invention, Figure 2 is a perspective view of the packaging unit being erected and formed from the packaging unit blank of Figure 1, and Figure 3 is a schematic view of an automated packaging line according to the invention.

Detailed description of a preferred embodiment of the invention In Figure 1 is shown one embodiment of a flat packaging unit blank according to the invention and in an intermediate position in the automated packaging line as shown in Figure 3. The packaging unit blank is erected around the article in the automated packaging line to form a packaging unit as shown in Figure 2. The packaging unit blank is made of paperboard, such as for example corrugated paperboard or cardboard, and in the illustrated embodiment the blank is specifically designed to form a impact-resistant packaging unit for a microwave oven. In the illustrated embodiment of the invention, the erected packa- ging unit has a hexagonal form in order to fit to the form of the packaged article. It should be noted, however, that also other forms of packaging units, such as a parallelepiped, triangular or other multi- sided forms, are conceivable within the scope of the invention.

The flat packaging unit blank 2 comprises a number of side panels 4, which are adapted to cover the side surfaces of the fragile ar- ticle in the erected position and are mutually delimited by fold lines 10.

The packaging unit blank 2 further comprises a number of fastener tabs 6, which are delimited with regard to the side panels by fold lines 12 and are adapted to bear on and be fastened to the side panels 4 in the erected and formed position.

Several strips 8 are provided on the panels 4 of the packa- ging unit blank and are fastened in a suitable manner, preferably by means of glue, such as hot melt adhesive, cold adhesive or some other type of adhesive, to the panels 4 of the packaging unit blank 2. In the embodiment as shown, the strips 8 extend transversely to the longitudi- nal direction of the packaging unit blank and also transversely to the direction of transfer of the packaging unit blank in the automated packaging line as will be further described below. However, it should be readily apparent that the strips also may be fastened to the panels 4 of the packaging unit blank in other directions with respect to the blank,

such as in the longitudinal direction of the blank. In the embodiment as shown, the impact-resistant elements are formed as strips. The ele- ments may however be differently formed and adapted to a specific pur- pose. The impact-resistant elements may advantageously be fastened to the specific parts of the panels 4 which bear on the most exposed and easily damaged parts of the fragile article. The impact-resistant ele- ments or strips 8 are made of a material having impact damping proper- ties and are preferably resilient. However, it is also possible to make the impact-resistant elements of shape-resistant materials within the scope of the invention. The resilience of the impact-damping material, advan- tageously makes it possible to fasten, in one piece, the impact-damping elements on several, mutually adjacent panels with intermediate fold lines 10, while the shape-resistant elements, which can not be folded, must be separated to several units. Materials suitable as impact-dam- ping materials are for example cellular polyethylene with different deg- rees of density, such as 30 or 40 kg/m3 for example. Also other types of polymer and rubber materials may be conceivable as impact-damping materials. The material of the elements or strips 8 and also the posi- tioning and extension of the strips on the packaging unit blank 2 may be chosen and adapted to different requirements for the packaged article of impact damping.

Figure 3 shows a schematic view of an automated packaging line according to the invention for articles, such as microwave ovens in this exemplifying embodiment. Figure 3 shows a packaging unit blank 2, made of corrugated paperboard, being fed in a packaging line 24 in a conventional manner in the direction of the arrow A, from a supply of blanks 20 to a first position of application 22. In the exemplifying em- bodiment, the impact-damping material is fed from a predetermined number of parallel material rolls 26, on which the damping strip mate- rial is wound. An adjusted length of the strip material is fed from each material roll and further to a cutting table 28. In the exemplifying em- bodiment, the cutting table 28 is arranged on the opposite side of the

packaging line 24 in respect of the supply of blanks 20. On the cutting table, the strips are cut to a length ready to use, whereupon the strips are being gripped by a transferring device (not shown), such as vacuum or mechanical gripping appliances or any other suitable means.

The transferring device transfers the damping strips 8 to predetermined positions on the flat packaging unit blank 2, where the strips are fastened to the panels by means of glue or in some other con- venient manner. Specific glue nozzles may be provided on the trans- ferring device, said nozzles being adapted to apply strings or spots of glue where the strips shall be positioned, either during the transfer of the strips or in a separate gluing step.

Alternatively, shape-resistant damping elements may be fed from a supply and be fastened, for example mutually parallel or inc- lined, to the panels of the packaging unit blank. It is also possible to mix different types of damping elements on one packaging unit blank when required.

The packaging unit blank 2 with the attached damping strips on the panels 4 of the blank is subsequently transferred in the direction of the arrow B to an erection and forming position 30. Spots or strings of glue are applied on the fastener tabs during this transfer, pre- ferably by means of fixed glue nozzles provided above the transfer line.

When the packaging unit blank 2 has reached the erection or forming position 30, the articles 32 are being fed from the side of the packaging line 24 and one article 32 is placed on the panel 4 of the packaging unit blank which forms the bottom surface in the erected packaging unit.

From this position, the packaging unit blank is erected and formed around the article and the panels 4 with the impact-resistant strips 8 are folded to bear on the sides of the fragile article and the fastener tabs 6 are folded towards the panels 4 and are fastened by means of spots or strings of glue applied on the insides of the fastener tabs. The packaged article, as shown in Figure 2, is fed from the erected, formed and sealed position to be stored and shipped.

It will be understood that the invention is not restricted to the embodiment as described above and that several modifications of the invention are conceivable within the scope of the claims.