WO1996007595A1

WO1996007595A1 - Loading pallet

Info

Publication number: WO1996007595A1
Application number: PCT/FI1995/000479
Authority: WO
Inventors: Kari Rantanen; Tommi BJÖRNMAN
Original assignee: Wisapak Oy Ab
Priority date: 1994-09-08
Filing date: 1995-09-07
Publication date: 1996-03-14
Also published as: FI944139A0; FI944139A; FI107904B

Abstract

The invention relates to a pallet (1) intended for one-time use, the pallet being made from recyclable cardboard. The pallet comprises beams (4) formed from tubular paperboard core pieces (2) axially perpendicular to the plane of the pallet and from corrugated board (3) surrounding them, arranged in parallel, and at least one element against the beams, such as a bottom slab (6) and/or a top slab (5) for tying the beams to one another. In the pallet according to the invention it is essential that in each beam (4) there is disposed, between the paperboard core pieces (2) and the corrugated board layer (3) under them, a rigid support plate (9) of glued and pressed paperboard, and that under each beam there is additionally a second paperboard support plate (13) of a similar type, in such a manner that the corrugated board layer is between the said support plates. The corrugated board layer (3) and the support plates (9, 13) together form a sandwich-type structure for receiving the bending stresses the pallet is subjected to. Each beam (4) may have, between the core pieces (2), openings (7) for a forklift truck or other such lifting device moving the pallet.

Description

Loading pallet

The present invention relates to a loading pallet which is in the main made from recyclable cardboard and which comprises beams formed from tubular paperboard core pieces axially per¬ pendicular to the plane of the pallet and from corrugated board surrounding them, arranged in parallel, and at least one ele¬ ment against the beams to tie the beams to one other.

Loading pallets are conventionally made of wood in order to obtain a high bearing capacity for the pallets. A wooden pallet in general endures being used a plurality of times, but still the pallets in practice end up at dumps quite rapidly.

It is also known to make a loading pallet from cardboard which can after use be recycled for pulping. The waste problem due to pallets is thereby avoided. However, cardboard pallets have had a disadvantage of having a lower strength and bearing capacity than have wooden pallets.

FI patent application 923261 describes a cardboard pallet in¬ tended mainly for one-time use; it comprises beams formed of parallel tubular paperboard core pieces and of cardboard sur¬ rounding them, the beams being disposed in the pallet so that the axes of the core pieces contained in the beams are perpen¬ dicular to the plane of the pallet. The cores, which are com¬ monly used as cores in paper rolls, are prepared by gluing spi¬ rally wound layers of paperboard one on top of another to form a thick mantle made up of a plurality of paperboard layers. This solution exploits the high compressive strength of the cores in the axial direction to increase the bearing capacity of the recyclable cardboard loading pallet.

An object of the present invention is to improve the structure of a loading pallet formed from beams comprising paperboard core pieces in such a way that the strength of the beams is improved. The invention is characterized in that each beam has a rigid paperboard support plate placed between the paperboard core pieces and the corrugated board layer under them, and tha under each beam there is additionally a second paperboard sup¬ port plate, so that the corrugated board layer is located be¬ tween the said two support plates.

In the structure according to the present invention, the sup¬ port plate located within the beam, between the paperboard cor pieces and the corrugated board layer, serves as a stiffener which facilitates the handling of the beams during the assembl stage of the pallet. The second paperboard support plate under the corrugated board further produces a sandwich-type struc¬ ture, in which, when the pallet is being loaded, the lower plate is subjected to tensile stress and the upper plate to compressive stress. According to the invention the support plates are preferably of paperboard prepared by gluing and pressing, in which case the essential idea is that their strength will exceed the strength of the corrugated board left between them. The corrugated board forms in the sandwich struc ture a lightweight and inexpensive layer the purpose of which is primarily to increase the thickness of the structure. Thick ness increases the bending strength of the structure and its capacity to bear especially point loads.

The said support plates, the width of which substantially cor¬ responds to the width of the beam and which extend continuousl from one end of the beam to the other, are preferably mutually substantially similar. The plates may be of a rigid, glued and pressed paperboard having a thickness within a range of approx. 1-10 mm.

In a pallet according to the invention, the element tying the parallel beams to each other may consist of a continuous top slab covering the pallet, the slab being preferably of multi- layered corrugated board. In addition to the top slab the pal¬ let may comprise a continuous bottom slab under the beams, this slab also being made of corrugated board. The bottom slab is preferably the bottommost element in the pallet, so that the lower support plate under each beam is left between the beam and the bottom slab. In this case the bottom slab will protect the support plates from being torn loose by shocks.

According to one preferred embodiment of the invention, each beam of the pallet comprises parallel core pieces disposed against each other in the middle of the pallet and at both ends, so that between the core pieces there will be left, on each side of the middle of the beam, openings delimited by the top slab or other similar element on top of the beams and ac¬ commodating the lifting device handling the pallet. In this case the lifting device may engage the rectangular pallet on any side of the pallet, i.e. by the said openings on the sides parallel to the beams or between the beams on the sides perpen¬ dicular to the beams. The lifting device used may be a forklift truck or a hydraulic pallet truck engaging the openings or the gaps between the beams. For a hydraulic pallet truck the bottom slab of the pallet may be equipped with openings which are located at the intersections of the gaps between the beams and the lines formed by the openings made in the said beams. In this case the truck may lift and move the pallet while the wheels of the truck are, through the openings in the bottom slab, in contact with the base, such as the ground or the floor.

The invention is described below in greater detail with the help of an example, with reference to the accompanying draw¬ ings, in which Figure 1 depicts a pallet according to the invention, made up of parallel beams and of bottom and top slabs, Figure 2 depicts the pallet in a horizontal section through II-II in Figure 1,

Figure 3 depicts a semifinished beam, in which the paperboard support plate and a number of card¬ board core pieces have been placed on a corru¬ gated board to be wound around them,

Figure 4 depicts a beam and the bottom and top slabs at an opening in the beam, in a section through IV-IV in Figure 1,

Figure 5 depicts a beam and the bottom and top slabs at the core pieces belonging to the beam, in a section through V-V in Figure 1,

Figure 6 depicts a longitudinal section of the beam through VI-VI in Figure 2, Figure 7 depicts an upper corner of the pallet, on a larger scale, Figure 8 depicts another pallet according to the inven¬ tion, in which the parallel beams are sur¬ rounded by a continuous folded plate piece, and

Figure 9 depicts a beam and the plates against it, in a section through IX-IX in Figure 8.

Figure 1 shows a mainly one-time-use pallet 1 according to the invention, made of recyclable cardboard. The pallet comprises three parallel beams 4 made up of mainly tubular paperboard core pieces 2 and of corrugated board 3 surrounding them, a cardboard top slab 5 covering the pallet, and a cardboard bot¬ tom slab 6 under the beams. Each beam 4 comprises, in accord¬ ance with Figure 2, three adjacent paperboard core pieces 2 in the middle of the beam and two adjacent paperboard core pieces 2 at each end of the beam. On both sides of the middle of each beam 4 there are thus openings 7 delimited by the top slab 5 of the pallet. In addition, in the bottom slab 6 of the pallet there are four openings 8, which are located at the gaps be¬ tween the parallel beams 4, at the intersections defined by the center lines between the beams and by the openings 7 in the beams. Each of the beams 4 of a pallet is formed, in accordance with Figure 3, of a suitably cut and folded sheet 3 of corrugated board, a support plate 9 of a rigid, glued and pressed paper¬ board, and in the example case seven tubular paperboard core pieces 2 arranged so that their axes are perpendicular to the plane of the pallet, i.e. to the plane of the top and bottom slabs 5, 6. At the time the beam 4 is being assembled, the wider tabs 10 in the sheet 3 of corrugated board at the core pieces 2 are folded around the core pieces 2 to surround them in accordance with Figures 4 and 5. The narrower edge strips 12 of the corrugated board sheet 3 at the notches 11 between the tabs 10 are folded at the beam openings 7 around the support plate 9, in accordance with Figure 4. The components of the beam 4 are preferably attached to one another with a glue separable in the recycling process, which glue can also be used in the joints between the beams and the bottom and top slabs 5, 6.

Figures 4, 5 and 6 further show that under each beam 4, between the beam and the bottom slab 6 bottommost in the pallet, there is disposed a second rigid support plate 13 of glued and pressed paperboard, the support plate extending continuously from one end of the beam to the other in the same manner as the support plate 9 inside the beam. The width of the said lower support plate 13 is the same as the width of the beam 4, i.e. slightly greater than the width of the upper support plate 9 inside the beam, which is the same as the diameter of the core pieces 2. The rigid support plates 9 and 13 and the corrugated board layer left between them and forming the bottom of the beam 4 together form a sandwich structure which receives loads in the manner of a trestle and in which the upper plate 9 is subjected to compression and the lower plate 13 to tension. The corrugated board layer 3 disposed in between serves as a light¬ weight element which increases the thickness of the structure and the bending strength of the structure. Figure 7, which depicts a corner of the loading pallet, shows that the top slab 5 has been assembled from sheets of double corrugated board by attaching three such sheets 14-16 one on top of another in such a manner that in the middle sheet 15 the corrugations are perpendicular to those in the sheets 14, 16 below and above. In the example depicted, one double corrugated board sheet has been used for the bottom slab 6.

The depicted pallet 1, with goods thereon, can be moved by means of a forklift truck, the lifting fork of which can be pushed between the bottom and top slabs either into the gaps between adjacent beams 4, in parallel to the beams, or into the openings 7 in the beams, transversely to the beams. Instead of a forklift truck it is possible to use in a similar manner a hydraulic pallet truck to be driven into the pallet, between the bottom and top slabs, the wheels of the truck being driven to the area of the openings 8 in the bottom slab, whereafter the pallet, with the goods on it, is lifted to bear on the truck for the purpose of being moved. Owing to openings 7 left in the core rows in the beams 4, the pallet 1 can be engaged from any of its sides, the core pieces in the middle of the beams and at their ends receiving loads perpendicular to the pallet, and the structure formed by the corrugated board layer and the support plates 9, 13 holding the beams together and stiffening them against bending.

Figures 8 and 9, which correspond to Figures 1 and 5 discussed above, show an embodiment of the pallet according to the inven¬ tion, differing from the one described above only in that, instead of a separate bottom slab it comprises a continuous plate piece 17 folded around the beams 4, the piece being a single corrugated board sheet. The orientation of the corruga¬ tions in the board 17 is perpendicular to the orientation of the beams 4. Furthermore, the top slab 5 of the pallet has three double corrugated board sheets 14, 15, 16 in accordance with what has been described above.

The said corrugated board slab 17 has openings 7 for a lifting device handling the pallet, and it has been folded around the beams 4 in such a manner that its edges 18 are against each other at the middle beam of the pallet, as can be seen from Figure 8. The support plates 13 are located between the beams 4 and the corrugated board slab 17.

For an expert in the art it is clear that the various embodi¬ ments of the invention are not limited to the example pre¬ sented, but may vary within the accompanying claim. It is, for example, possible that the pallet comprises a plurality of beam layers one on top of another, wherein the mutually crosswise beams are attached to one another. The added beam layers may in this case replace the bottom slab and/or the top slab of the above example. On the other hand, it is possible for the pallet to have, in addition to bottom and top slabs, one or a plurali¬ ty of intermediate slabs separating the beam layers.

Claims

1. A pallet (1) which is made in the main from recyclable cardboard and which comprises beams (4) formed from tubular paperboard core pieces (2) axially perpendicular to the plane of the pallet and from corrugated board (3) surrounding them, arranged in parallel, and at least one element (5, 6, 17) against the elements for tying the beams to one another, char¬ acterized in that each beam (4) has, disposed between the paperboard core pieces (2) and the corrugated board layer (3) under them, a rigid support plate (9) of paperboard, and that under each beam there is additionally a second paperboard sup¬ port plate (13) in such a manner that the corrugated board layer is located between the said two support plates.

2. A pallet according to Claim 1, characterized in that the support plates (9, 13) are of paperboard having a thickness of approx. 1-10 mm, prepared by gluing and pressing.

3. A pallet according to Claim 1 or 2, characterized in that it comprises a cardboard top slab (5) disposed on top of the beams (4) and tying the beams to one another.

4. A pallet according to any of the above claims, charac¬ terized in that it comprises a cardboard bottom slab (6) dis¬ posed under the beams (4) and tying the beams to one another.

5. A pallet according to Claim 3 and 4, characterized in that the parallel beams (4) are tied to one another by means of a continuous sheet piece (17) folded around the beams.

6. A pallet according to Claim 4 or 5, characterized in that the said support plates (13) under the beams (4) are lo¬ cated between the beams and the bottom slab (6, 17).

7. A pallet according to any of Claims 3-6, characterized in that the top slab (5) and/or the bottom slab (6), or the sheet piece (17) surrounding the beams, is made up of cor¬ rugated board.

8. A pallet according to any of the above claims, charac¬ terized in that each beam (4) comprises adjacent core pieces (2), touching one another, in the middle of the beam and at its both ends, in such a manner that between the core pieces, on both sides of the middle of the beam, there are left openings (7) which are delimited by the top slab or other such element on top of the beams and can be engaged by a lifting device handling the pallet.

9. A pallet according to Claim 8, characterized in that the bottom slab (6, 17) is provided with openings (8) which are located at the gaps between the parallel beams (4) on the transverse lines determined by the said openings (7) in the beams.