WO2002000514A1

WO2002000514A1 - Plastic coated wooden pallet board strip

Info

Publication number: WO2002000514A1
Application number: PCT/AU2001/000751
Authority: WO
Inventors: Lazer Berelovich
Original assignee: Vicfam Plastics Pty Ltd
Priority date: 2000-06-29
Filing date: 2001-06-25
Publication date: 2002-01-03
Also published as: AUPQ845700A0

Abstract

A lead board (4, 4a) or plank or dunnage strip for a apallet comprises a core of wood (8) and a covering of impact resistant plastics material (10) such as linear low density polyethylene moulded around the core to a thickness of between about 5 to 10 milimiters. The wooden core can have a series of uniformly spaced holes (12) so that plastics will flow through the holes to ensure the plastics covering is firmly fixed to the core. The plastics material covering (10) is wear resistant, is capable of absorbing impact damage from the tines of a fork lift without splitting and retains the moisture content of the wood and thereby prevents warping of the wood when unseasoned wood dries; while the core (8) provides the required rigidity and load-bearing characteristics to the lead board or plank (4, 4a).

Description

PLASTIC COATED WOODEN PALLET BOARD OR STRIP

The present invention principally relates to pallets, particularly wooden pallets. The invention is also applicable to other related articles used in the transportation and handling of goods.

Wooden pallets for the transportation of a wide variety of goods conventionally comprise a series of parallel wooden beams to the upper surfaces of which are fixed a series of parallel planks or boards which extend transversely with respect to the beams and which form the load-carrying surface of the pallet. The under surfaces of the beams at least at each end portion of the pallet are attached to ground-engaging planks or boards which likewise extend transversely to the beams. The beams are configured to permit entry of the tines of a fork lift into the interior of the pallet in a direction parallel to the axis of the beams whereby the tines engage the load-carrying surface of the pallet from underneath. The upper and lower boards at each end of the pallet where the tines enter into the pallet are known as lead boards. The lead boards are prone to substantial damage in use, particularly impact damage, resulting from engagement of the front ends of the fork tines if, as if often the case, the fork lift operator has not set the tines at the right height to enter into the interior of the pallet without interference by the lead boards. As a result, the lead boards tend to represent the zones of maximum wear of the pallet. The lead boards tend to splinter and split under the effects of impact and other damage during use and within the working life of a pallet the lead boards may require replacement several times.

According to the present invention, there is provided a lead board for a pallet, said board comprising a core of a substantially rigid load-bearing material and a covering of an impact-resistant plastics material moulded around the core.

Advantageously, the core consists of a wooden board having through-holes between the opposed surfaces of the board and through which the plastics material flows during moulding to ensure the plastics material is firmly retained to the core. Advantageously, the plastics material is a linear low density polyethylene.

The invention also provides a pallet with lead boards as defined above.

According to another aspect of the invention, there is provided a dunnage strip comprising a core of a rigid load-bearing material and a plastics covering of an impact- resistant material moulded around the core.

Advantageously, the core consists of a length of wood having apertures extending between opposed surfaces through which the plastics material flows during moulding to ensure the plastic is firmly anchored to the core.

Embodiments of the invention will now be described, by way of example only with reference to the accompanying drawings in which:- Figure 1 is a perspective view of a pallet having lead boards in accordance with the preferred embodiment of the invention; and

Figure 2 is a cross section through the lead board.

With reference to Figure 1, a pallet comprises parallel wooden beams 2 with parallel planks or boards 4 attached to the upper surfaces of the beams 2 to form the load- carrying surface of the pallet. The under surfaces of the beams 2 are attached to further parallel planks or boards 6. Pallets of this type are often constructed so that the planks 6 at the underside of the beams can alternatively form a load-carrying surface if the pallet is inverted and in that case the number of planks 6 at the underside of the beams 2 will correspond to those at the upper side of the beams 2. With the exception of the lead boards which form the subject of this invention, the boards 4, 6 will typically consist of wood. The four lead boards in the pallet illustrated are designated as 4a, and 6a.

In accordance with the present invention, each of the lead boards 4a, 6a (Figure 2) comprises a wooden core 8 around which is moulded a tough substantially rigid plastics 10 which is wear resistant and which is capable of absorbing impact damage specifically from the tines of a fork lift, without splitting. The core 8 is in the form of a wooden plank to provide the required rigidity and load-bearing characteristics to the lead board. The core 8 is provided with a series of uniformly spaced holes 12 between its upper and lower surfaces so that when the plastics covering is moulded around the core, the plastics material will flow through the holes to ensure that the plastics covering is firmly fixed to the core. It has been determined that linear low density polyethylene provides a particularly satisfactory covering for the core, with the core being completely encased within the covering and the covering having a thickness of between about 5 and 10 mm. Linear low density polyethylene moulded around the core is fixed to the core not only by flow of the plastics material through the holes of the core during moulding, but also due to shrinkage effects. Although linear low density polyethylene has been found to be particularly suitable, it is envisaged that other plastics would have applicability.

The composite lead board 4a, 6a consisting of the wooden core 8 encased within the plastics material 10 is fastened to the beams 2 in the same manner as the other boards whereby the construction of the pallet is otherwise conventional. The encasement of the wooden core 8 by the plastics covering 10 retains the moisture content of the wood and thereby prevents warping and splitting of the wood as can arise when unseasoned wood dries.

The general principles of the invention described herein are also applicable to other articles used in the transportation of goods for packaging. One particular example is so- called dunnage which conventionally consists of wooden strips beneath rolls of steel and the like on the tray of a truck to prevent movement and slippage. In accordance with the invention, dunnage of strip-like form consists of a wooden core encased in plastics material in the same manner as that described above, with the wooden core being provided with apertures along its length through which the plastics material flows during moulding in order to ensure firm attachment to the core.

Although a wooden core is especially appropriate for these applications as wood has the necessary strength and rigidity whilst being relatively inexpensive, nevertheless cores of other material having the required characteristics could alternatively be provided.

The embodiment has been described by way of example and modifications are possible within the scope of the invention.

Throughout this specification and claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers.

Claims

CLAIMS:-

1. A lead board for a pallet, said board comprising a core of a substantially rigid load- bearing material and a covering of an impact-resistant plastics material moulded around the core.

2. A pallet lead board according to claim 1 , wherein the core consists of a wooden board having through-holes between the opposed surfaces of the board and through which the plastics material flows during moulding to ensure the plastic material is firmly retained to the core.

3. A pallet lead board according to claim 1 or claim 2, wherein the plastics material is a linear low density polyethylene.

4. A pallet comprising parallel beams supporting a load-carrying surface, said surface being formed at each of its opposed end portions with a lead board as claimed in any one of claims 1 to 3.

5. A dunnage strip comprising a core of a rigid load-bearing material and a plastics covering of an impact-resistant material moulded around the core.

6. A dunnage strip according to claim 5, wherein the core consists of a length of wood having apertures extending between opposed surfaces through which the plastics material flows during moulding to ensure the plastic is firmly anchored to the core.

7. A dunnage strip according to claim 5 or claim 6, wherein the plastics material is a linear low density polyethylene.