AU5765301A - Pallet and method for making the same - Google Patents

Description

1

AUSTRALIA

Patents Act 1990 Suomen Kuitulava Oy

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT 6 Invention Title: Pallet and method for making the same The following statement is a full description of this invention including the best method of performing it known to us:- The invention relates to a pallet, comprising beams in a parallel arrangement, composed of tubular core members of cardboard as well as a sheet board Surrounding the latter, as Well as at least one element set against the beams for bracing the beams to each other. The invention relates also to a method for making such a pallet.

Pallets have been traditionally made from wood for providing pallets with a high load-bearing capacity. A wooden pallet is generally capable of handling a number of operations, but still in practice the pallets have quite soon ended up in waste disposal sites.

For environmental reasons there has been an increasing tend towards board-made pallets, which can be recycled after their service to the production of recycled pulp.

Fl patent 93933 describes a mainly disposable board-made pallet, comprising beams composed of parallel tubular core members of cardboard and a sheet board surrounding the same, which are positioned in the pallet in such a way that the core members contained in the beams have their axes perpendicular to the plane of the pallet. The cores, which is are generally used as paper roll cores, are manufactured by bonding spirally wound plies of cardboard on top of each other for a tube provided with a thick casing constituted by a plurality of plies of cardboard. The solution makes use of a high compression strength in the axial direction of cores for providing a board-made pallet with a sufficient load-bearing capacity.

F1 patent 94852 further describes a manufacturing method for a board-made pallet, wherein the cardboard core members are flattened for increasing the size of their bondable contact surfaces for increased rigidity of the beams and load-bearing capacity of the pallet.

In service, the board-made pallet may be subjected to damp conditions, which require that wetting of the board and, thus, degradation of the pallet be prevented The adhesive paste used in cardboard cores is weather-resistant and the corrugated board used as a wrapper for the beams can be provided with a water-repellent coating, such means being suffcient in terms of preventing normal moisture and splash waters from harming a pallet. However, if pallets are being permanently parked on wet foundations or kept for a lengthy period outdoors exposed to rain, it has been necessary to treat such pallets separately with moisture barriers.

In pallets as set forth in the cited FI patents 93933 and 94852, which represent pallet types currently available in the marketplace, the cardboard core members in the pallets are surrounded by a corrugated sheet board in such a way that the sheet covers the beam along its sides, yet leaves the beam uncovered at both ends. This 15 type of beams are exposed to moisture penetration through the chamfered edges of a corrugated sheet board present at the ends of a beam, which are constituted by sheet ~.cutting surfaces with no moisture barrier reg'ardless of whether the corrugated board is otherwise provided with a moisture barrier coating. Functioning as legs for a pallet, the beams rest e.g. against a wet floor, a rain-swept loading dock or truck bed, or against wet ground, the result being a gradual soaking of the beams and possibly the board material of an entire pallet. The elimination of said leakages would result in the survival of a pallet without soaking even on wet foundations without having to spray the pallet separately with protective agents.

Another problem appearing in pallets based on open-ended beams is the fact that the beam ends are highly susceptible to damage. Between a cylindrical cardboard core member and the edges of a corrugated sheet board remain cavities, which are readily engageable by implements of pallets handling machines or other foreign objects, which may cause tearing of the board. In order to avoid this, some commercially available pallets have the beam ends rounded by cutting the corrugated sheet board to comply with the shape of a cardboard core. Such reshaping of the beam does not provide a solution to the above-discussed wetting problem It is an object of this invention to provide a pallet, wherein the foregoing, beamstructure related problems are avoidable. The inventive pallet is characterized in that the beams are encapsulated by folding the sheet board around the respective cardboard core members, such that the sheet constitutes a bottom and sides for the beam and moreover closes the beam at each end thereof.

The inventive boxing of pallet beams constitutes a simple means for providing a closed beam structure, which is less susceptible to damage than prior art open-ended beams. In addition, the solution enables the unprotected, water absorbent chamnfers of a sheet board to be eliminated from the ends of a beam.

The basic aspect in terms of moisture proofing the beams is that the board material ~:constituting a wrapper for the beams is at least over its external surface provided with a moisture barrier coating, such as e.g. a water repellent polymer or wax coating. The closure of a beam end is effected by pleating and folding the respective end of a sheet board constituting the wrapper and, as the beam is disposed in a pallet in such a way that the folding direction is upwards, the sheet shall have its unprotected chamfers, raised from the plane of the beam bottoms, which is particularly exposed to the moistening effect of a wet foundation. The sheets will have a moisture proofed surface completely intact in the plane of the beam bottoms, the absorption of water into the board material being effectively eliminated.

Thle pleats of a sheet board forming at the beam ends are most preferably folded inside the beam, whereby the beam remains smooth over its external surfaces. The pleats can be sealed tightly to the internal surfaces of a beam for flurther reducing a possibility of water penetration into the beam and thereby its possible absorption into the board material.

In the most simple design of pallet the beams arm arranged side by side at a distance from each other in a single tier. The beams function as legs for the pallet and the overlying, pallet-holding element can be constituted by a top panel of corrugated board, wherein the flutes progressing perpendicularly to the direction of the beams. For example, a sandwich panel of corrugated cardboard, which consists of two fluted layers and three liners and which is double-folded and serving as a top panel, provides a pallet with robustness suffcient e.g. for the handling and storing of general cargo in food industry and commercial distribution chain.

Optionally the construction of a pallet may comprise parallel beams in two overlying, mutually criss-crossing tiers. In such a pallet, the beams can be directly 15 secured to each other with nothing else needed for holding the pallet together, but in terms of its loading capacity, the pallet should preferably be provided with a top :panel of e.g. corrugated board and possibly also with an intermediate sheet board between the overlying tiers of beams.

Referring to pallets composed of two superimposed tiers of beams, it is particularly important to use close-ended beams constructed according to the invention as lower-tier beams, which function as legs for the pallet and are most exposed to soaking on a wet foundation. However, the invention is preferably applied in all beams included in a two-tier pallet, which also affords a consistent appearance to the pallet.

Preferably, the inventive pallet is composed of recyclable board essentially in its entirety. The pallet sections are bondable to each other with an adhesive, such as e.g. a polyvinyl alcohol chloride adhesive (PYAC), which produces a watertight joint and which in a pulping process separates from pulp the same way as the adhesive of cardboard cores and the polymer (especially polyethylene) or wax used as a moisture barrier coating.

The inventive method for making a pallet as described above is characterized in that a sheet cut out of polymer-or wax-coated board is subjected to folding to produce a blank, upon which are arranged cardboard core members in a row and which is bent along folds for a casing surrounding the core members from a bottom, sides, and ends thereof and is adhesive-bonded for a beam, and that thus obtained beams are arranged side by side such that the cardboard core members have their axes extending perpendicularly to the plane of a resulting pillet, and that on top of the beams are secured by adhesive-bonding one or more pallet-holding elements parallel to the plane of the pallet. Said element may be preferably constituted by a top panel of e.g. corrugated board or by a second tier of beams crosswise to the above-discussed beams.

The invention will now be described in more detail by way of examples, with reference made to the accompanying drawing, in which I shows one pallet of the invention diagonally from above, fig. 2 shows *the pallet of fig. I diagonally from below, 3 shows a sheet board provided with folds, as well as cardboard core members arranged thereon and capable of being assembled for a beam constituting a leg for the pallet of fig. 1, and fig. 4 shows another pallet of the invention, having parallel beamns criss-cross~Lg in two tiers.

Figs. 1 and 2 illustrate a pallet 1 of the invention intended essentially for disposable use and obtained by adhesive bonding from recyclable fibre material. The pallet 1 comprises a top panel 2, as well as three parallel, equally spaced, rectangularly prismatic beams 3, which function as legs for'the pallet. The top panel 2 consists of a double-folded sheet of corrugated board, which has its abutting edges form a seam or joint 4 on the bottom surface of the panel, which is visible in fig. 2. The direction of corrugations along the top panel 2 is perpendicular to the beams 3.

The structure and mode of assembly of the beams 3 are best shown in fig. 3. The figure illustrates a sheet 5, which is cut out of corrugated board lined on either side with polyethylene or other such water-repellent coating material and which is turned into a box blank by providing it with folds 6. The folds 6 divide the blank 5 into sections 7-il, which comprise a bottom 7, sides 8, a cover 9, ends 10 for the beam 3, as well as pleats I1I for the beam ends. The section 7, which constitutes the beam 15 bottom, is provided wit~h a row of six tubular cardboard core members 12 in such a way that the axes thereof are perpendicular to the plane of the blank 5. The beam 3 is built by folding the blank 5 around the cardboard core members 12, such that the blank corrugated board encloses the core members 12 within itself. In a folding process, the pleats 11 are bent inside the beamn against the internal surfac~es of the beam sides 8, and the blank has its protruding side flaps 9 end up adjacent to each other on top of the cardboard core members 12 for the beam cover. Thebemi assembled by using a hot melt adhesive, such as e.g. a PVAC adhesive, capable of bonding the beam bottom 7, sides 8, cover 9, and ends 10 securely to the cardboard core members 12, the pleats 11 securely to the internal side surfaces, and furthermore the cardboard core members 12 securely to each other.

The assembly process of the beam 3 can be preferably accompanied by the flattening of cardboard core members described in Fl patent 94852 for prestressing the beam and increasing the size of contact surfaces to be bonded together. As a result of the flattening, the cardboard core members 12, which in fig. 3 have the shape of a circular cylinder, deform in such a way tha the shape thereof approaches a rectangle. By way of this reference, the Fl publication 94852 is incorporated as part of the present specification.

The attachment of the beams 3 obtained as set forth above for the legs of the pallet 1 shown in figs. 1 and 2 is effected by bonding. e.g. with the same adhesive as used for assembling the beams. The adh~esive is required to hive not only a good jointing capability but also to withstand a temperature of about 1 10*C, whereby it separates in a pulping process from pulp the same way as the polymer coating of corrugated board.

The beams 3 are disposed in the pallet I such that the cardboard core members 12 have their axes perpendicular to the plane constituted by the top pallet panel 2, whereby the cores are effective in terms of carrying a load applied to the pallet. In 15 addition, the beams 3 are arranged in such a way that the ends 10 and the pleats 11 thereof are folded upwards from the beam bottom 7, whereby the chamnfers of these 9**.9..sections in the pallet are positioned substantially flush with the bottom surface of the top panel 2, at a distance from the beam bottom 7 equal to the beam height. The beam bottom 7 is entirely covered by corrugated board moisture proofed by a polymer coating, which does not absorb water in itself from a wet foundation. Thus, the chamfers, along which the cardboard blank 5 has been cut and which are without a moisture barrier, are all located far away from the beam bottom 7 and furthermore partially inside the encapsulated beam as well as in a shelter provided by the top panel 2 covering the beam. Moreover, the adhesive joints in a pallet can be used to participate in sealing said chamnfered surfaces sensitive to mxoisture- The pallet 1 of fig. I is a two-tier assembly, which may be constructed by using the encapsulated or boxed beams 3 obtained as set forth above. The pallet 1 comprises parallel beams 3 arranged on top of each other in two tiers, such that the beamns of different tiers are perpendicular to each other. The pallet includes a top panel 2 of 8 corrugated board, which may be similar to that shown in figs. 1 and 2. In addition, between the superimposed tiers of beams is fitted an intermediate panel 13, which may be similar to the top panel 2. The most essential aspect in the pallet is to encapsulate in accordance with the invention the lower-tier beams functioning as its legs, which are particularly exposed to soaking from a wet foundation, but in order to reduce the beams' susceptibility to damage and also for giving a consistent appearance to the pallet, the boxed beams are also used for the upper tier of beams in the pallet of fig. 4.

It is obvious for a person skilled in the art that various applications of the invention are not limited to what is set forth above as examples, but may vary within the scope of the appended claims. For example, the sheet 5 folded around the core members in pallets may comprise a single-ply cardboard instead of corrugated ar board.

e eee

Claims (11)

1. A pallet comprising beams in a parallel arrangement, composed of tubular core members of cardboard as well as a sheet board ,surrounding the latter, as well as at least one element set against the beams for bracing the beams to each other, characterized in that the beams ,are encapsulated by folding the sheet board around the respective cardboard core members such that the sheet constitutes a bottom and sides for the beam and moreover Closes the beam at each end thereof.

2. A pallet as set forth in Claim 1, characterized in that the board surrounding the core members of the beams is provided with a water- repellent polymer or wax coating.

3. A pallet as set forth in claim 1 or 2, characterized in that the beams are disposed in the Pallet in such a way that the end of a sheet constituting the beam *end ,as well as pleats of the sheet adjacent thereto, are folded upwards.

4. A pallet as set forth in claim 3, characterized in that the pleats of the sheet are folded inside the beam A pallet as set forth in claim 4, characterized in that the pleats are sealed against ant internal surface of the beam 'by adhesive bonding.

6. A pallet as Set forth in anY of the preceding claims, characterized in that the beams are arranged in the pallet side by side in a single tier.

7. A pallet as set forth in claim 6, characterized in that the pallet comprises a top panel of corrugated board, which braces together the parallel beams functioning as pallet legs.

8. A pallet as set forth in any of claim 1-5, characterized in that the pallet is provided with the parallel beams in two superimposed, criss-crossing tiers.

9. A pallet as set forth in claim 8, characterized in that the pallet comprises an intermediate board panel fitted between the tiers of beams. A pallet as set forth in claim 8 or 9, characterized in that the pallet comprises a top board panel covering the upper tier of beams.

11. A pallet as set forth in any of the preceding claims, characterized in that it is essentially completely fabricated from recyclable board.

12. A pallet as set forth in claim 11, characterized in that the pallet has its 15 sections bonded to each other with an adhesive separable in a pulping process. see*@:13. A method for making a pallet as set forth in any of the preceding claims, 00*0characterized in that a sheet cut out of polymerorwxcaebadisujctdo folding to produce a blank ,upon which are arranged cardboard core members in a row and which is bent along folds for a casing surrounding the core members from a bottom sides and ends, thereof and is adhesive-bonded for a beam, that thus obtained beams are arranged side by side such that the .cardboard core members have their axes extending perpendicularly to the plane of a resulting pallet and that on top of the beams are secured by adhesive- bonding one or more pallet-holding elements parallel to the plane of the pallet.

14. A method as set forth in claim 13, characterized in that the beams are arranged side by side in a single tier and are braced to each other by means of a top 11 panel of corrugated board, in which the corrugations extend perpendicularly to the direction of the beams. DATED THIS 26 DAY OF JULY 2001 SUOMEN KUITULAVA OY Patent Attorneys for the Applicant: F.B.RICE CO