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TECHNICAL FIELD 5 The present invention relates to a packaging preform of the kind set forth in the preamble of Claim 1.

Such a preform is used for making a corner protector intended to be placed around a corner on e.g. a box- 10 shaped article in order to protect said corner against impact during handling and transport, as the corner protector, when subject to impact, will absorb the energy of the impact by elastic or permanent deformation.

15 BACKGROUND ART

A corner protector of the kind referred to above is known from DE published specification No. 3 010 066. This corner protector is produced from thin plastic material, which in certain countries can give rise to

20 problems, when the used corner protector is to be disposed of as waste material. Further, plastic is a homogeneous material, the permanent deformation of which occurs in the form of sudden local weakenings in the side walls of the projections, providing no substantial

25 absorption of impact energy.

DISCLOSURE OF THE INVENTION

It is the object of the present invention to avoid these disadvantages and to provide a packaging preform making

30 it possible to produce a corner protector exhibiting no problems with regard to disposal of wast material, said corner protector being able to absorb a substantial amount of impact energy, both by elastic deformation and especially by permanent (plastic) deformation of

35 the raised portions or projections.

The object stated above is achieved with a packaging element of the kind referred to initially, additionally exhibiting the features set forth the characterizing clause of Claim 1. Since the packaging preform is produced from fibre pulp material, it is possible after ^• the use of the corner protector to recycleythe material or destroy it without problems by burning, and this material - is also bio-degradable. In contrast to the plastic material used in the packaging preform referred to above, the material used in the packaging preform according to the present invention is inhomogeneous and consists of a great number of inter-entangled fibres, for which reason the permanent deformation of the projections partially takes place in the form of a local disintegration of these fibres, enabling the material to absorb a substantial quantity of impact energy. This effect is further enhanced by the special arrangement of the projections in the region of the corner point, enabling the projections to support each other.

The embodiments of the packaging preform according to the present invention set forth in Claims 2 and 3 are especially suited for making a corner protector with moderate shock-absorbing properties, suitable for packaging relatively light articles, whilst the embodiments set forth in Claims 4-6 are especially suitable for making corner protectors with relatively large shock-absorbing properties, suitable for packaging heavier articles.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present specification, the present invention will be explained in more detail with reference to the exemplary embodiments of a packaging preform according to the invention shown in the drawings, in which

Figure 1 shows a first exemplary embodiment of the packaging element as viewed against a major surface,

Figure 2 shows a corner protector made by suitably 5 folding the packaging preform shown in Figure 1, as viewed in the direction of two of the side panels and the locking panel locked to one of these, towards the third side panel,

10 Figure 3 in perspective shows the corner protector shown in Figure 2 as viewed towards the internal corner.

Figure 4 shows a second exemplary embodiment of the packaging preform as viewed towards a major surface, 15

Figure 5 is a sectional view along the line V-V in Figure 4,

Figure 6 in perspective shows a corner protector made

20 by suitably folding the packaging preform shown in

Figures 4 and 5, viewed towards an external corner, and

Figure 7 is a sectional view along the line VII-VII in Figure 6.

25

DESCRIPTION OF THE PREFERRED EMBODIMENTS The packaging preform according to the present invention shown in Figure 1 is generally designated 1, and it has been produced in a manner known per se by aspirating

30 fibre pulp onto a liquid-permeable mould surface, followed by drying and possibly subsequent pressing of the pulp material having been deposited, as well as

_¥ subsequent imprinting and punching or cutting of the blank thus produced, from which blank a number of

35 packaging preforms according to the present invention may be produced. The packaging preform 1 has a

substantially plane base, generally designated 2. A number of raised portions or projections, to be described in more detail below, extend from the base 2 on the side of the packaging preform 1 facing the viewer in Figure 1, said side being referred to as the "front side" in what follows. As it is commonly known in pulp articles of the kind referred to here, such as trays and cartons for eggs, these raised portions correspond to similarly shaped recesses in the rear side (not shown) of the packaging preform 1, the dimensions of these recesses, however, being smaller than the dimensions of the corresponding raised portions or projections by one. thickness of the material, this thickness being relatively constant over the whole of the packaging preform 1.

As shown in Figure 1, the base 2 is square in shape, and by means of folding lines 3 and 4 and an incision line 5 it is divided in to four square panels 6, 1 , 8 and 9, of which the panels 6, 7 and 8 in the finished corner protector constitute the latter\s mutually orthogonal side panels, whereas the panel 9 is a locking panel, in the finished corner protector adapted to be in locking engagement with the side panel 6 in a manner to be described below.

On the side panel 6 there are four raised portions or projections, viz. two diagonally mutually opposing projections 10a and 10b, equal in size and shaped like a truncated pyramid with a substantially square base, of which the projection 10a is situated in the corner region of the side panel 6 adjacent to the center of the base 2 , as well as two projections 11a and lib, equal in size and having an L-shaped base, equally diagonally mutually opposed and with the external corners of the L's, which have equally long legs, facing each

other, their side and end surfaces forming obtuse angles with the base 2. The projections 11a and lib have flat tops 9 at the same height as the tops of the projections 10a and 10b. The end surfaces of each of the L-shaped projections 11a and lib are each in substantial alignment with a side surface of one of the projections 10a and 10b, and those L-legs of the projections lla and lib, that are parallel to the folding line 4 and the incision line 5 respectively, lie at a distance from these lines that is greater than the common height of the projections on the side panels 6, 7 og 8.

At that outside edges which is parallel to the folding line 3, the side panel 7 has two projections 12a arid 12b, equal in size and having a rectangular base, their side and end surfaces forming obtuse angles with the base 2, as well as a flat top, their side surfaces being parallel to the outside edge of the side panel 7, said projections 12a and 12b being situated adjacent each other and the "inside" of the L-shaped projection lib on the side surface 6. In addition to this, the side panel 7 has a projection 13 with a T-shaped base, having side and end surfaces forming obtuse angles with the base as well as a flat top lying in the same height above the base 2 as the tops of the projections 12a and 12b and the tops of the projections on the side panel 6. The beam of the T is parallel to the projections 12a and 12b with the same extent as these on the side panel 7, and on the base 2 it is situated adjacent the space between the projections 10a and lib on the side panel 6. The stem in the T-shaped projection 13 is short and protrudes from the beam in the T offset outwardly from the latter's centre towards the free edge of the side panel 7, and extends towards the folding line 3.

The side panel 8 has four projections 14, 15a, 15b.and 16, of which the projection 14, being situated in the internal corner of the side panel 8, has an L-shaped base with side and end surfaces forming obtuse angles with the base 2, as well as a flat top, the legs of the L being equal in size and parallel to the three edges of the side panel 8 and with the external corner of the L facing towards the central region of the side panel 8. The distance between the folding line 4 and the leg of the projection 14 parallel to it is greater than the common height of the projections on the side panels 6, 7 and 8 by a certain small distance. The projections 15a and 15b have a rectangular base, their end and side surfaces forming obtuse angles with the base 2 and their flat tops lying opposite and having the same length as a respective one of the legs of the L- shaped projection 14 along the respective outside edge of the side panel 8, the projection 15a being parallel to the folding line 4 and the projection 15b being parallel to the folding line 3. The space between the projection 15a and the leg of the L-shaped projection 14 parallel to it lie opposite the stem in the L-shaped projection 13 on the side panel 7 and has a greater width than this stem. The projection 16 is shaped like a truncated pyramid with a substantially square base and is situated in the outermost corner of the side panel 8, its outer side surfaces being substantially in alignment with the outer side surfaces of a respective one of the projections 15a and 15b.

The locking panel 9 has four projections 17a, 17b, 18a and 18b, of which the projections 17a and 17b are equal in size and shaped like truncated pyramids with substan¬ tially square base and flat top, these projections 17a and 17b being dimensioned and situated on the locking panel 9 in such a manner, that in the finished corner

protector, they can be in locking engagement in the recesses on the rear side of the packaging preform 1 corresponding to the projections 10a and 10b on the side panel 6. The projections 18a and 18b have an L- shaped base, side and end walls forming obtuse angles with base 2, and flat tops. The projections 18a and 18b er dimensioned and situated on the locking panel 9 in such a manner, that in the finished corner protector, each of them can be in locking engagement with the respective recesses on the rear side of the packaging preform 1 corresponding to the L-shaped projections 11a and lib.

From the packaging preform 1 thus described, a finished corner protector 20 is produced in the following manner:

First, the side panel 6 is folded upwardly from the plane of the base 2 through 90° about the folding line 4. This causes the lower end of the beam in the T-shaped projection 13 on the side panel to lie in the space between the projections 10a and lib on the side panel 6, while the lower end of the rectangular projection 12a on the other side panel 7 is placed in the internal corner in the L-shaped projection lib on the first side panel 6. Then, the third side panel 8 is folded upwardly through 90° about the folding line 3, causing that leg of the L-shaped projection 14 on the side panel 8 lying closest to the folding line 3 to lie in the space between the frusto-pyramidal projection 10a on the first side panel 6 and the stem of the T-shaped projection 13 on the side panel 7, while the other leg of the L-shaped projection 14 comes to rest in the space between the frusto-pyramidal projection 10a and the L-shaped projection 11a on the side panel 6. The end of the rectangular projection 15a on the side panel 8 closest to the folding line 3 will lie in the space between the

stem of the T-shaped projection 13 on the side panel 7 and the free edge of this panel, whilst the end of the rectangular projection 15b closest to the^folding line 14 will lie in the internal corner of the L-shaped projection 11a on the side panel 6.

) At this stage, the side panels 6, 7 and 8 are at right angles to each other, and the corner protector is completed by folding the ^* locking panel 9 through 90° about the folding line 4, causing each of the frusto- pyramidal projections 17a and 17b to be brought into locking engagement inside a respective one of the recesses in the rear side of the first side panel 6 corresponding to the frusto-pyramidal projections 10a and 10b on this panel, while the L-shaped projections 18a and 18b are brought into engagement in respective recesses in the rear side of the side panel 6 corresponding to the L-shaped projections 11a and lib. This locking engangement is the more powerful, as the surfaces of the packaging preform 1 are inherently rather rough.

The corner protector 20 produced by this folding operation is shown in Figures 2 and 3, in which the various parts of the packaging preform 1 having been shown in Figure 1 will be indentifiable by their reference numbers, for which reason these Figures will not be described in more detail, except for mentioning that the special "entanglement" of the projections in the corner region of the corner protector 20, being the central feature of the invention, is clearly shown in Figure 3 , showing how the projection 10a is closely embraced by and within the projections 13 and 14. At this point, it should also be mentioned that the packaging preform 1 according to the present invention, if solely folded at right angles about the folding line

4, can be used as an edge protector for protecting a side edge of a packaged article.

Those projections 10a, 10b, 16, 17a and 17b, which are described above and shown as being shaped liked truncated pyramids, may also have a frusto-conical shape or a shape between these extremes.

The packaging preform 101 shown in figures 4 and 5 consist of a base 102, which in the situation shown in Figures 4 and 5 is substantially plane, as well as a number of raised portions or projections with roughly the same wall thickness as the base 102, viz. four corner projections 103 and 104, of which the corner projections 104 are somewhat lower than the corner projections 103, a number of side projections 105 and 106, of which the side projections 106 are somewhat lower than the side projections 105, and - four central projections 107 and 108, of which the central projections 108 are somewhat lower than the central projections 107.

All the projections have generally square top surfaces 109.

As shown in Figure 4 and 5, the base 102 is shaped with an incision line 110 extending from the edge of the preform between the projections 105 and 106 uppermost in Figure 4 to the centre point 119 of the base 2. From this centre point 119 to the remaining edges on the base 102 extend three folding lines, viz. a first folding line 111, a second folding line 112 and a third folding line 113 - the reference numbers are given in the same sequence as the sequence, in which the preform may be folded to form a corner protector to be described

below. For the sake of good order, at this point it should be noted that the projections 103-108 shown in Figure 4 are to be perceived as pointing towards the viewer, i.e. that the top surfaces 109 are closer to the viewer than the base 102.

Those side surfaces 105a, 106a, 107a and 108a on the projections 105, 106, 107 and 108, that are situated closest to the incision line 110 or the folding lines 111-113, are inclined away from the incision line and the folding lines respectively under an angle 118 of approximately 45° with the base 102. This makes it possible to fold the preform at right angles about the folding lines 111-113 at the same time as the top surfaces 1 or 9 on the central projections 107 and 108 will lie close together in the finished corner protector, cf. Figure 7.

When the packaging preform 101 shown in Figures 4 and 5 is to be folded so as to form a corner protector as shown in Figure 6 and 1 , the first step consist in folding a first panel 114 upwardly - i.e. towards the viewer in Figure 4 - about the first folding line 111, until the panel 114 is at right angles to a second panel 115 situated on the other side of the first folding line 111. Then, a third panel 116 is folded upwardly about the second folding line 112, causing a fourth panel 117 to follow suit upwardly, so that the panels 116 and 117 form a right angle both with the first panel 114 and the second panel 115. Finally, the fourth panel 117 is folded about the third folding line 113, bringing it into abutment against what is now the outside of the first panel 114, the four projections 104, 106 and 108 with reduced heights in the fourth panel 117 fitting into the projections 103, 105 and 107 in the first panel 114. In this manner it is possible, by suitably

dimensioning the projections 104, 106 and 108 relative to the projections 103, 105 and 107, to achieve a locking frictional engagement, at least with regard to the corner projections 103 and 104 and the side projections 105 and 106, so that the corner protector shown in Figures 6 and 7 produced by this folding operation will retain its shape, in spite of a possible tendency for the material in the base 102 to "spring back" about the folding lines ill, 112 and 113.

The corner protector 120 produced by this folding operation is shown in Figures 6 and 7, in which the various parts of the preform 101 shown in Figures 4 and 5 will be identifiable by the reference numbers, for which reason further discussion of these Figures should be unnecessary. It should be noted, however, that especially Figure 7 shows how the central projections 107 and 108 with their top surfaces 109 form a particulary strong corner support, e.g. for protecting the corner of an apparatus packaged in a corrugated- paper box with a number of corner protectors of the construction shown placed between the corners and the apparatus and the corners of the corrugated-paper box. A further improvement may be achieved if the central projections 107 are shaped in such a manner, that their mutually facing side walls 107a in a manner not shown abut against each other in the finished corner protector shown.

The fibre pulp referred to may be produced from e.g. vegetable fibre mass, especially wood pulp, or paper pulp, including such made from recycled paper.

LIST OF PARTS

1 packaging preform

2. base

3 folding line

4 folding line

5 incision line

6 square panel/side panel

7 square panel/side panel

8 square panel/side panel

9 square panel/locking panel 10a raised portion/projection 10b raised portion/projection 11a raised portion/projection lib raised portion/projection 12a raised portion/projection 12b raised portion projection

13 raised portion/projection

14 raised portion/projection 15a raised portion/projection 15b raised portion/projection 16 raised portion/projection 17a raised portion/projection 17b raised portion/projection 18a raised portion/projection 18b raised portion/projection 20 corner protector

101 packaging preform

102 base

103 corner projections

104 corner projections

105 side projection 105a side surface

106 side projection 106a side surface

107 central projection