FI94852B - Pallet and its manufacturing method - Google Patents

Abstract

The invention relates to a pallet (1) made of recyclable cardboard and its method of manufacture. Beams (2) are formed of tube-like paper-board core pieces (3) arranged in line and of the cardboard (4) surrounding them, the beams being attached to each other crosswise in two layers so that the axes of the core pieces included in the beams are placed perpendicularly to the level of the pallet. In addition to the beams (2), the pallet (1) may include a covering plate (14) of cardboard and an intermediate plate (15) of cardboard between the layers of the beams. The invention is characterized in that, when assembling the beams (2), the paper-board core pieces (3) of essentially a round cross section are compressed in order to flatten them in the cross direction of the resulting beam. The diameter of the core pieces (3) is decreased by 1-20 %, suitably about 10 % in said direction during flattening. The flattening increases the contact surfaces between the core pieces (3) and the surrounding cardboard (4) on which the core pieces and the cardboard are glued to each other.

Description

1 94852

The present invention relates to a method of manufacturing a pallet, in which beams are formed from tubular cardboard sleeve pieces arranged in a row 5 and the surrounding cardboard, which are cross-connected to at least two layers so that the axes of the parallel cardboard sleeve pieces belonging to the beams are aligned. In addition, the invention relates to a pallet obtained according to the method.

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Pallets have traditionally been made of wood, which has given the pallets a high load capacity. A wooden pallet usually lasts numerous uses, but still the pallets end up in landfills quite quickly in practice.

It is also known to make a pallet from cardboard, which after use can be recycled back into the production of recycled pulp. This avoids the waste problem caused by pallets. However, the disadvantage of cardboard pallets compared to wooden pallets has been their lower strength and load-bearing capacity.

F1 patent application 923261 describes a cardboard pallet, mainly for single use, comprising beams formed of parallel tubular cardboard sleeve pieces and the surrounding cardboard, which are fastened to each other in two layers so that the axes of the sleeve body parts of the beams are in one direction. The cores, which are commonly used as • cores for paper rolls, are made by gluing helically twisted; the paperboard layers superimposed into a tube having a thick jacket consisting of a plurality of paperboard layers. The solution utilizes high compressive strength in the axial direction of the cores to improve the load-bearing capacity of the cardboard, recyclable pallet.

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The object of the present invention is to develop a cardboard pallet manufacturing technique according to FI patent application 923261 so that the strength of the pallet is improved. The pallet manufacturing method according to the invention is characterized in that when assembling the beams, pieces of carton sleeves with a substantially round cross-section are pressed in the transverse direction of the beam to flatten them.

94852 2

It follows from the flattening of the cardboard sleeve pieces according to the invention that the contact surfaces between the sides of the pieces and the cardboard layers forming against them, forming the sides of the resulting beam, which act on the as mounting surfaces between the parts, grow. The sleeve pieces and the surrounding cardboard layers can thus be glued together 5 from an even wider area, whereby the beam becomes stiffer. If the sleeve pieces are lined together in a row, the flattening also increases the mutual contact surfaces of the pieces, whereby these can also be glued or otherwise attached to each other more firmly. Thanks to the invention, the bending strength of the beam is increased and the susceptibility to nmjaculation is reduced, and the ability of the pallet assembled from the beams to carry a particularly point-like load is improved. This increased strength of the pallet is due not only to the tighter contact and stronger attachment of the core pieces and the surrounding cardboard layers, but also to the prestressing provided in the flattened beams, which contributes to the load capacity of the pallet.

By flattening the initially round cardboard core pieces according to the invention, their diameter in the transverse direction of the beam to be formed can be reduced by 1-20%, preferably by 5-15% and optimally by about 10%. The diameter of the sleeve pieces in the longitudinal direction of the beam can be kept substantially unchanged.

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In practice, the assembly of the beams entering the pallet can be carried out by placing the pieces of cardboard sleeves against each other in a row on a cardboard sheet with folds corresponding to the edges of the beam. The band delimited by adjacent fold lines of the sheet on which the core pieces are placed is slightly narrower than the core pieces. 25 diameter. The sheet is then bent around the core pieces while squeezing the sides of the pieces so that they flatten to match the diameter of the strip of sheet below them. The core pieces and the bent cardboard sheet pressed around them in said manner are preferably sealed together with an adhesive pre-applied to the contact surfaces, whereby in the resulting beam the core pieces remain flattened and tensioned inside the surrounding cardboard layer on all sides.

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The assembly of the beams, as well as the fastening of the beams to each other as a pallet, can take place using only glue as the fastening means, which is separated from the pulp in the material recycling process after the use of the pallet. Suitable adhesives are e.g. hot melt 35 adhesives and quick-drying cold adhesives. On the other hand, it is also possible to use rivets to secure the glue joints of the pallet.

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If the goods to be loaded are self-supporting, e.g. rigid boxes corresponding to the size of the pallet or the like, the pallet can be formed from only beams fastened to each other crosswise. However, it is advantageous to provide the pallet with a top plate of rigid cardboard attached to the beams, in which case the pallet is also suitable for loading smaller or looser goods, such as sacks.

It is also advantageous to provide the pallet with a spacer between the overlapping beam layers, suitably rigid cardboard, which further increases the bending strength of the pallet.

A pallet according to the invention, made in accordance with the above, comprising beams consisting of tubular cardboard sleeve pieces arranged in a row and surrounding cardboard, which are connected to each other in at least two layers so that the axes of the cardboard sleeve pieces belonging to -15 pieces are flattened in the transverse direction of the beam so that their diameter in said direction is smaller than in the longitudinal direction of the beam. The diameter of the cardboard sleeve pieces in the transverse direction of the beam can then be 80-99%, preferably 85-95% and ideally about 90% of the diameter of the pieces in the longitudinal direction of the beam.

The invention will now be described in more detail by way of example with reference to the accompanying drawings, in which Figure 1 shows cardboard sleeve pieces arranged in a row on a corrugated cardboard sheet wrapped around them, Figure 2 shows cardboard sleeve pieces a beam formed of a sheet, the figures "I ·" show the end of the beam according to three alternative embodiments 3a-3c of the invention, Fig. 4 shows a part of the beam of Fig. 3 seen from above and partially cut away, t 4 94852 Fig. 5 shows a process in which a corrugated sheet wrapped around the cardboard sleeve pieces to provide the beam according to Fig. 3, Fig. 6 shows a load consisting of the beams according to Fig. 3, the top plate and the spacer between the beam layers 5 the pallet and Fig. 7 shows the corner of the pallet according to Fig. 6 on a larger scale.

The cardboard pallet 1 according to the invention, shown in Fig. 6, comprises beams 2 according to Fig. 3 fastened to two overlapping layers, assembled from a row of tubular cardboard sleeve pieces 3 and a corrugated cardboard sheet 4 wrapped around them.

According to Figures 1 and 2, the sheet 4 is provided with folds 6 corresponding to the edges 5 of the beam 2 to be formed, which divide the sides 7 of the sheet beam into strips 8-10 forming. The central strip 8 of the sheet, on which the cardboard sleeve pieces 3 are arranged in a row against each other, corresponds in width to the transverse width of the beam 2 to be formed. The intermediate strips 9 of the sheet correspond in width to the height of the beam 2 to be formed, which is substantially the same as the length of the sleeve pieces 3 in their axial direction.

The edge strips 10 of the sheet, which, according to Figures 3 and 4, form one of the sides of the beam 2, are each half the width of the middle strip 8.

Fig. 1, which shows the sheet 4 and the cardboard sleeve pieces 3 • 25 arranged in a row thereon before bending the sheet around the pieces, shows that the diameter of the cardboard sleeve pieces 3 round in cross section is slightly larger than the width of the middle strip 8 of the sheet. However, in connection with the formation of the beam 2, the cardboard sleeve pieces 3 are flattened in the transverse direction of the beam so that in the finished beam their transverse diameter is the same as the transverse width of the beam according to Fig. 4. In lithization, the diameter of the sleeve pieces 3 in the transverse direction of the beam 2 can be reduced by 1-20%, preferably 5-15% and most preferably about 10%, while in the longitudinal direction of the beam the sleeve pieces 3 retain their original diameter, provided they have been in contact with each other to each other. In flattening, the carton sleeve pieces 3 are deformed so that the contact surfaces between them and the sides 7 of the beam formed by the sheet 4, as well as their mutual contact surfaces, which would be substantially linear without flattening, increase considerably. Mil ti IlilJU i 94852 5 wider. These contact surfaces act as fastening surfaces with which the sheet 4 and the cardboard sleeve pieces 3 are glued to each other in the beam 2.

Figure 3a shows a beam 2 provided with a stiffening plate 16 glued under a layer 4 of corrugated cardboard 5 at its bottom, which is glued and compressed board. The stiffening plate 16 extends the width of the beam 2 from its end to end. The stiffener 16 is thus, like other parts of the pallet, a recyclable material and is intended to increase in particular the ability of the beam to carry a point load on the pallet.

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Fig. 3b shows a beam 2, which differs from that shown in Fig. 3a only in that the stiffening plate 16 is placed inside the base of the corrugated board 4 of the beam immediately below the cardboard sleeve pieces 3. Fig. 3c further shows an alternative embodiment in which the rigid element 15 inside the plate-like corrugated board layer 4 extends in addition to the bottom of the beam 2 to the second vertical side of the beam. The stiffener 16, 17 of recyclable material is bonded in place with glue and is intended to distribute the point load on the pallet over the entire length of the beam and thus reduce its risk of buckling.

Fig. 5 schematically shows a process in which a corrugated cardboard sheet 4 is bent around cardboard sleeve pieces 3 and in which at the same time the sleeve pieces are pressed in the transverse direction of the resulting beam to flatten them. The process uses press members 13 pivotally mounted on the conveyor belt 11 with respect to the joint points 12, between which the sheet 4 and the sleeve pieces 3 are forced with the press members in the open position due to the curvature of the belt. As the belt 11 straightens, the press members 13: rotate towards each other to a position where the distance between them is equal to the transverse width of the beam to be formed. The sleeve pieces 3 are thus pressed between the press rollers 13, which flattens them to the desired diameter according to the dimensions of the beam. After flattening, the edge 4 of the sheet 4 is finally turned over the core pieces 3 and the compression is maintained until the parts of the beam act. the binding adhesive has hardened.

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The pallet 1 according to Fig. 6 comprises a rigid cardboard top plate 14, an underlying beam-35 layer of three mutually parallel beams 2, a lower rigid cardboard spacer 15 below them and a lower beam layer of three lower parallel beams 2. The beams 2 are located in said layers perpendicular to each other. When • · 6 94852 in each floor the parallel beams 2 are spaced apart, it is possible to move the platform with a lifting fork inserted between the beams.

It can be seen from Fig. 7 showing the corner of the pallet 1 according to Fig. 6 that both the top-5 plate 14 and the spacer plate 15 consist of double corrugated board, the direction of the corrugations being perpendicular to the direction of the beams 2 immediately below the plate. When placed in this way, the plates 14, 15 increase the rigidity of the pallet, in addition to which the spacer plate acts in the pallet as a fastening element which fastens the overlapping beam layers to each other and helps to keep the pallet together.

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It will be clear to a person skilled in the art that the various embodiments of the invention are not limited to the example described above, but may vary within the scope of the appended claims.

15: κι i emi i l i st;

Claims (11)

A method of manufacturing a pallet (1), wherein beams (2) are formed from a row of tubular cardboard sleeve pieces (3) and surrounding cardboard (4), which are connected to each other in at least two layers so that the axes of parallel cardboard sleeve pieces belonging to the beams abut perpendicularly, characterized in that when the beams (2) are assembled, cardboard sleeve pieces (3) with a substantially round cross-section are pressed in order to flatten them in the transverse direction of the resulting beam. Method according to Claim 1, characterized in that the diameter of the cardboard core pieces (3) in the transverse direction of the beam (2) is reduced by 1 to 20% during flattening. Method according to Claim 2, characterized in that the flattening of the cardboard core pieces (3) in the transverse direction of the beam (2) is reduced by 5-15%, preferably by about 10%. Method according to one of the preceding claims, characterized in that the flattening of the cardboard core pieces (3) is carried out in such a way that the diameter of the pieces 20 in the longitudinal direction of the beam (2) remains substantially unchanged. Method according to one of the preceding claims, characterized in that the cardboard sleeve pieces (3) are arranged in a row on a cardboard sheet (4) which is bent around the pieces, and that the pieces are flattened during bending of the sheet. Method according to one of the preceding claims, characterized in that the cardboard core pieces (3) and the surrounding cardboard (4) are bonded to the beam (2) with glue. 30 Method according to one of the preceding claims, characterized in that the pallet (1) is further provided with a top plate (14) of rigid cardboard and at least one spacer plate (15) between the beam layers. 7 94852 Pallet (1) made by a method according to any one of the preceding claims, comprising beams (2) of tubular cardboard sleeve pieces (3) arranged in a row and surrounding cardboard (4), which are cross-connected to at least two layers. so that the axes of the cardboard sleeve pieces 94852 belonging to the beams are perpendicular to the plane of the pallet, characterized in that the cardboard sleeve pieces (3) are flattened in the transverse direction of the beam (2) so that their diameter in said direction is smaller than in the longitudinal direction. 5 Pallet according to Claim 8, characterized in that the diameter of the cardboard sleeve pieces (3) in the transverse direction of the beam (2) is 80 to 99%, preferably 85 to 95% and most preferably about 90% of the diameter of the pieces (3) in the longitudinal direction of the beam. 10 Pallet according to Claim 8 or 9, characterized in that the pallet (1) comprises, in addition to the beams (2), a top plate (14) of rigid cardboard and at least one spacer plate (15) between the beam layers. Pallet according to one of Claims 8 to 10, characterized in that in each beam (2) the cardboard layer (4) surrounding the cardboard sleeve pieces (3) is made of corrugated cardboard and «I 1 ai i nm i.i i a. 9,94852