NL1018677C2 - Pallet made from cardboard with beams made from cardboard tubes - Google Patents

Abstract

A pallet, including beams in a parallel arrangement, composed of tubular core members of cardboard substantially perpendicular to the plane of the pallet as well as a sheet of board surrounding the tubular cores, as well as at least one element set against the beams for bracing the beams, characterized in that the beams are encapsulated by folding tthe sheet of board around the respective cardboard core members such that the sheet constitutes a bottom and sides for the beam and closes the beam at each end thereof.

Description

Pallet and method for manufacturing thereof

The present invention relates to a pallet comprising beams arranged in parallel, as well as at least one element that is placed against the beam for joining the beams to each other, wherein the beams consist of tubular core members of cardboard as well as a sheet of cardboard folded around the core members, so that the sheet of cardboard forms a bottom side and sides for the beam and moreover closes the beam at each end thereof.

The invention also relates to a method for manufacturing such a pallet.

Pallets are usually made from wood to provide pallets with a large bearing capacity. A wooden pallet can generally handle a number of handling operations, but in practice pallets often turn out to be disposed of as waste.

For environmental reasons, there is an increasing tendency towards pallets made of cardboard that are recycled after use for the production of recycled pulp. In the Finnish patent 93933 a substantially disposable cardboard made pallet is described, consisting of beams comprising parallel tubular core members of cardboard and a sheet of cardboard surrounding it, which are arranged in the pallet such that of the core members arranged in the beams 20 center line is perpendicular to the plane of the pallet. The cores generally used as paper roll cores are made by bonding spirally wound layers of cardboard to each other for a tube with a thick housing advanced by a plurality of layers of cardboard. The solution uses the high compressive strength in the axial direction of cores to provide a pallet made of cardboard with sufficient bearing capacity.

The Finnish patent 94852 also describes a method for manufacturing a cardboard-made pallet, in which the cardboard core members are flattened to increase the size of the bonding contact surfaces for increased stiffness of the beams and load capacity of the pallet.

During operation, pallets made from cardboard can be subjected to moist conditions, which means that moistening of the cardboard and thus deterioration of the pallet must be prevented. The adhesive used in the cardboard cores is weather resistant and the corrugated cardboard used as a wrapper for the beams can be provided 1018677

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2 of a water-repellent coating, which is sufficient with regard to the prevention of damage to the pallet due to normal moisture and splashed water. However, if pallets are permanently placed on wet surfaces or exposed to rain outside for a longer period of time, it has been found necessary to treat such pallets with moisture barriers.

With pallets as described in the aforementioned Finnish patents 93933 and 94852, being pallets currently available on the market, the cardboard core members in the pallets are surrounded by a sheet of corrugated cardboard such that the sheet covers the beam along the sides but still the beam at both ends uncovered late. This type of beams is exposed to moisture penetration by the beveled edges of a sheet of corrugated cardboard present at the ends of a beam formed by the cutting surfaces of the sheet without a moisture barrier regardless of whether the corrugated cardboard is further provided with a moisture barrier coating. When functioning as feet for a pallet, the beams rest, for example, on a wet floor, a loading platform dampened by rain or on a bearing surface of a truck or on a wet bottom, whereby the beams and possibly the cardboard material of the entire pallet gradually absorb moisture. Excluding such leaks would mean the continued existence of a pallet without moisture absorption, such as on wet foundations, without the pallet having to be sprayed separately with protective means.

Another problem with pallets with open-ended beams is that the beams are very susceptible to damage. Between a cylindrical cardboard core member and the edges of a sheet of corrugated cardboard, spaces remain, into which fittings of pallet handling devices or other foreign parts can easily enter, whereby cracks of the cardboard can be caused. To avoid this, for certain commercially available pallets, the beam ends are rounded by cutting the corrugated cardboard sheet to correspond to the shape of the cardboard core. Such a change in the shape of the beam does not provide a solution for the above-mentioned wetting problem.

A pallet according to the first part of claim 1 is known from DE-9010271U. A cardboard material is used that would offer sufficient protection against moisture.

It is an object of this invention to provide a pallet in which the above problems with regard to beam structure are avoided.

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In addition, an object of the present invention is to effectively solve moisture problems.

This object is achieved with a pallet described above in that the cardboard surrounding the core members of the beams is provided with a water-repellent polymer or wax coating and that the beams are arranged in the pallet such that the end of a sheet forming the beam end and of the adjacent sheet are folded upwards.

According to the invention with regard to making the beams moisture-proof, the cardboard material which forms an envelope for the beams is provided at least over the outer surface thereof with a moisture-sealing coating such as a water-repellent polymer or wax coating. The wrapping of a beam end is achieved by folding and folding the respective end of a cardboard sheet that forms the wrapper and when a beam is arranged in a pallet in such a way that the folding direction is upwards, the unprotected will 15 inclines of the sheet lie above the surface of the bottom of the beam, which bottom is particularly exposed to wetting by a wet surface. Of the sheets, the moisture-resistant surface in the plane of the beam bottom will be completely intact, whereby the absorption of water in the cardboard material is effectively excluded.

More specifically, the folds of a sheet of cardboard formed at the beam ends are folded into the beam, whereby the outer surface of the beam remains smooth. The pleats can be firmly attached to the internal surfaces of a beam to further limit the possibility of water penetrating into the beam and thus its possible absorption into the cardboard material.

In the simplest design of a pallet, the beams are arranged side by side at a distance from each other in a single series. The beams serve as feet for the pallet, and the element holding the covering pallet can be formed by a top panel of, for example, corrugated cardboard, the waves extending perpendicular to the direction of the beams. A composite panel of corrugated cardboard comprising two corrugated layers and three liners, which is double folded and serves as a top panel, provides, for example, a pallet with sufficient rigidity for handling and storing general cargo in the food industry and in commercial distribution chains.

101867? 4

The construction of a pallet may optionally comprise parallel beams in two superimposed series of mutually intersecting rows. With such a pallet, the beams can be directly attached to each other without further measures being necessary to keep the pallet together. In order to increase the load capacity, the pallet should preferably be provided with a top panel of, for example, corrugated cardboard and possibly also with an intermediate sheet of cardboard between the rows of beams lying one above the other.

With regard to pallets consisting of two sets of beams lying one above the other, it is practically important to use closed-ended beams constructed according to the invention as beams according to a lower series which serve as feet for the pallet and are most exposed to moisture absorption at a wet surface. However, the invention can also be applied to all beams comprising a two-series pallet that also enables a consistent appearance for the pallet.

Preferably the pallet according to the invention consists entirely of recyclable cardboard. The pallet parts can be adhered to each other with an adhesive such as a polyvinyl alcohol chloride adhesive (PVAC), which produces a watertight connection and which, during pulping, separates in the same way as the adhesive of cardboard cores and the polymer (in particular polyethylene) or wax which is used as a moisture-tight coating.

The method according to the invention for manufacturing a pallet as described above is characterized by a cut out portion of polymer or wax coated cardboard being subjected to folding to produce a blank on which cardboard core members are arranged in series and which are folded along is folded for a housing that surrounds the core members from an underside, sides and ends thereof and is adhered with adhesive for a beam, the beams thus obtained being arranged side by side such that from the cardboard core members the center lines are perpendicular to the extend flatly from a pallet, and wherein one or more pallet-joining elements are attached to the top of the beams adhering parallel to the plane of the pallet. Such an element is preferably formed by a top panel, for example of corrugated cardboard, or by a second series of beams transversely to the beams described above.

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The invention will now be described in more detail with reference to examples with reference to the accompanying drawings, in which:

FIG. 1 shows a pallet according to the invention diagonally in top view;

FIG. 2 shows the pallet according to fig. 1 diagonally in bottom view; FIG. 3 shows a sheet of cardboard provided with folds and cardboard core members arranged thereon and which can be joined to form a beam that forms a base for the pallet according to FIG. 1, and

FIG. 4 shows another pallet according to the invention with parallel beams intersecting in two layers.

FIG. 1 and 2 show a pallet according to the invention mainly for disposable use and obtained by adhesive bonding from recyclable fiber material. The pallet 1 comprises a top panel 2 as well as three parallel equally spaced rectangular prismatic beams 3 which serve as feet for the pallet. The top panel 2 consists of a folded sheet of corrugated cardboard, the adjacent edges of which form a seam or joint 4 on the lower surface of the panel, which is visible in Fig. 2. The direction of the undulations along the top panel 2 is perpendicular to the beams 3.

The construction and manner of joining the beams 3 is most clearly apparent from Fig. 3. This figure shows a sheet 5 cut from corrugated cardboard, coated on both sides with polyethylene or other water-repellent coating material and which becomes a box blank by providing it with folds 6. The folds 6 separate the blank 5 into parts 7-11, comprising a bottom 7, sides 8, a cover 9, ends 10 for the beam 3 and folds 11 for the beam ends. The part 7 which forms the bottom of the beam is provided with a row consisting of six tubular cardboard core members 12 arranged in such a way that the axes thereof extend perpendicularly to the plane of the blank 5. The beam 3 is built up by folding the blank 5 along the cardboard core members 12, such that the blank corrugated cardboard encloses the core members 12 therein. During folding, the folds 11 in the beam are bent against the internal surfaces of the beam sides 8 and the projecting side flaps 9 of the blank end close to each other at the top of the cardboard core members 12 for the beam cover. The beam is assembled using a hot-melt adhesive such as, for example, a PVAC adhesive that secures the beam bottom 7, sides 8, cover 9, and ends 10 to the cardboard 101887. 6 can adhere core members 12, the folds 11 can securely adhere to the inner side surfaces and moreover can securely adhere the cardboard core members 12 to each other.

The manner of joining the beam 3 can preferably be realized by flattening the cardboard core members as described in the Finnish patent 94852 for preloading the beam and increasing the contact surfaces to be attached to each other. By flattening, the cardboard core members 12 deform into shape. 3 have the shape of a circular cylinder, such that its shape approximates to a rectangle. Reference is hereby made to the Finnish patent publication 94852.

The attachment of the beams 3 obtained in the above manner to the feet of the pallet 1 shown in Figs. 1 and 2 is accomplished by bonding, for example with the same adhesive as used for joining the beams. The adhesive used must not only have good bonding capacity but must also be able to withstand a temperature of about 110 ° C at which it separates from pulp during pulping in the same way as the polymeric coating of corrugated cardboard.

The beams 3 are arranged in the pallet 1 in such a way that the center line of the cardboard core members 12 is perpendicular to the plane formed by the upper pallet panel 2, whereby the cores are efficient in carrying a load placed on the pallet is going to be. Moreover, the beams 3 are arranged such that the ends 10 and fold 11 thereof are folded upwards from the beam bottom 7, whereby the chamfers of these parts in the pallet are substantially flush with the lower surface of the top panel 2 are arranged on a bottom The position of the beam bottom 7 which is equal to the beam height. The beam bottom 7 is completely covered with corrugated cardboard which is made moisture-resistant by a polymeric coating and itself does not absorb water from a wet surface. The chamfers along which the cardboard blank 5 has been cut, and which have no moisture barrier, are all far away from the beam bottom 7 and moreover partially within the encased beam as well as in a protection provided by the top panel 2 covering the beam. In addition, the adhesive connections in a pallet can be used to assist in sealing those chamfered surfaces that are sensitive to moisture.

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The pallet 1 of Fig. 4 is an assembly consisting of two series, which can be manufactured using the encased or enclosed beams 3 obtained in the above manner. The pallet 1 comprises parallel beams 3 which are arranged on top of each other in two layers so that the beams of the different layers are perpendicular to each other. The pallet comprises a corrugated cardboard top panel 2 which may be similar to that shown in Figs. 1 and 2. Moreover, an intermediate panel 13 may be arranged between the superimposed layers of beams, which panel may be similar to the top panel 2. The most essential aspect of the pallet is the enclosing in accordance with the invention of the beams in the bottom layer which serve as feet 10, which are particularly exposed to absorption on a wet surface, but to reduce the sensitivity of damaging the beams. and to also give the pallet a consistent appearance, the box-shaped beams are also used for the top layer beams in the pallet of Fig. 4.

It will be apparent to those skilled in the art that various embodiments of the invention are not limited to the examples given above, but may change within the scope of the appended claims. The sheet 5 folded around the core members in the pallets can, for example, comprise a single-layer cardboard instead of corrugated cardboard.

1018677

Claims (12)

1. Pallet comprising beams arranged parallel, as well as at least one element placed against the beam for joining the beams to each other, wherein the beams consist of tubular core members of cardboard as well as a sheet of cardboard folded around the core members, so that it sheet of cardboard forms a bottom and sides for the beam and moreover closes the beam at each end thereof, characterized in that the cardboard (5) surrounding the core members (12) of the beams (3) is provided with a water-repellent polymer or wax coating and that the beams (3) are arranged in the pallet (1) such that the end of a sheet forming the beam end (10) as well as folding (11) of the adjacent sheet are folded upwards. Pallet according to claim 1, characterized in that the folds (11) of the field (5) are folded into the beam (3). 15 Pallet according to claim 2, characterized in that the folds (11) with a clasp. adhesive to be attached to an internal surface of the beam (3). Pallet according to one of the preceding claims, characterized in that the beams (3) are arranged next to each other in a single series in the pallet (1). Pallet according to claim 4, characterized in that the pallet (1) comprises a top panel (2) corrugated cardboard that connects the parallel beams (3) that function as pallet feet. 25 Pallet according to one of claims 1 to 3, characterized in that the pallet (1) is provided with parallel beams (3) which are arranged in two superimposed, intersecting layers. Pallet according to claim 6, characterized in that the pallet (1) comprises an intermediate cardboard panel (13) arranged between the beam series. 1018677 Pallet according to claim 6 or 7, characterized in that the pallet (1) comprises an upper cardboard panel (2) covering the upper series of beams. 9. Pallet according to one of the preceding claims, characterized in that it is substantially entirely made from recyclable cardboard. Pallet according to claim 9, characterized in that parts (2, 3,5,12) of the pallet (1) are adhered to each other with an adhesive that can be separated in a method for pulping. 10 A method for manufacturing a pallet according to any of the preceding claims, characterized in that a sheet cut from polymer or wax coated cardboard is folded to form a blank on which cardboard core members are arranged in a row and which fold along is bent into a housing which surrounds the core members from a bottom, sides and ends and is adhered with adhesive for a beam, the beams thus obtained being placed next to each other such that from the cardboard core members the center lines perpendicular to the plane extends from an emerged pallet and that one or more pallet-retaining elements are fixed to the beams parallel to the surface of the pallet with an adhesive adhesive. 20 A method according to claim 11, characterized in that the beams are placed side by side in a single series and are connected to each other by means of a top panel corrugated cardboard, the corrugations extending perpendicular to the direction of the beams. 25 1018677