WO2011020475A1

WO2011020475A1 - Corrugated paper pallet

Info

Publication number: WO2011020475A1
Application number: PCT/DK2010/050213
Authority: WO
Inventors: Lars Bryde
Original assignee: Bentsen Emballage A/S
Priority date: 2009-08-21
Filing date: 2010-08-19
Publication date: 2011-02-24
Also published as: DK177008B1; EP2467305A1; EP2467305A4; EP2467305B1

Abstract

There is provided a corrugated paper pallet comprising a pallet base and support members made from layers of corrugated paper sheets. L-shaped lists made from a rigid material are secured to the support members thereby raising the support members slightly from the ground. Such a pallet is lightweight, recyclable and durable.

Description

CORRUGATED PAPER PALLET

FIELD OF THE INVENTION

The present invention is related to pallets and, more specifically, pallets constructed of corrugated components that include a corrugated sheet and corrugated support blocks stabilised by lists. Such pallets are lightweight, recyclable and durable.

BACKGROUND OF THE INVENTION

Paper pallets are gaining in popularity as they provide consumers with an easily recyclable option as compared to the standard wood pallets that have been used for years. However, paper pallets while desirably recyclable often bring other undesirable features. For instance, paper pallets often provide the user with a pallet of reduced strength as compared to a wood pallet of similar size and configuration. The reduced strength limits the load that the pallet may carry and additionally, allows for the damaging of the pallet itself under heavy loads. Traditionally, pallets have been made of wood planks nailed together. In one common structure, a series parallel of upper wood planks are nailed to the top of three transversely extending, parallel, and equally-spaced wood support planks. Similarly, a series of parallel lower wood planks are nailed to the bottom of the three support planks. Forklift forks can slide under the upper planks in the two parallel channels formed by the three spaced support planks. The forklift can then raise its forks, which lifts the pallet and anything mounted on it.

In an industrial packaging or shipping environment, wood pallets can withstand the often great abuses to which they are subject. The pallet may be dropped or rammed by a forklift or some other machine. The pallet may be slid around on a floor or stored outside in the rain or snow. It may be tossed around vigorously when being stored, stacked, or moved. A wood pallet can withstand a great deal of this type of use and abuse.

Wood pallets are, however, expensive, because they eventually breakdown. When they do, little of the wood is useable to make new pallets. To make new pallets, new wood is often required, which requires cutting down of further trees. This is not only expensive but of great environmental concern.

Wood pallets are also relatively heavy. Their weight increases the cost of storing or shipping products with them. Wood pallets are also dangerous in that, wear and tear causes the wood to splinter and nails to become exposed. The splinters and exposed nails can damage the product being shipped as well as the human operators working with the pallets.

One attempt at a solution to the problems with wood pallets has been the paper pallet. The paper pallet can be made out of honeycomb paper components. The cellular honeycomb core provides remarkable compression strength, lightweight, and significantly improved cushioning ability over the wood pallet. Further, the paper components are totally recyclable as well as biodegradable. The paper pallet can thus be shredded, baled, and sold as recyclable paper, or alternatively returned to the environment through biodegrading. One prior art paper pallet is made by International Honeycomb Illinois, Inc. This Honeycomb paper pallet is made of corrugated Kraft Honeycomb runners or blocks glued to the bottom of a corrugated Honeycomb pallet base or to the bottom of a corrugated cardboard carton. This paper pallet can weigh as little as 95% of the traditional wood pallets of a similar configuration. It also eliminates the need for nails and the problems that exposed nails and wood splinters can cause.

For pallets requiring fork access from only two opposing sides, the paper pallet can use three runners in parallel under the deck or carton. The three parallel runners form two parallel fork channels separated by the center runner. The forks from the forklift then penetrate the two fork channels to lift the pallet or carton.

In other forms of the prior art paper pallets, three parallel rows of three spaced apart paper honeycomb blocks are glued to the underside of a rectangular Honeycomb paper base. In this form, the forks can slide under the base from any of the four sides of the pallet. The three rows each form two channels for the forks on two opposing sides of the pallet, and the three lines of three spaced apart blocks form two transverse fork channels on the other two opposing sides of the pallet. In yet another prior art paper pallet three parallel rows of three equally spaced Honeycomb paper blocks are glued to the underside of a rectangular paper Honeycomb base. One parallel paper Honeycomb runner is glued to the bottom of each row of blocks. In this manner, the blocks form channels for forks to penetrate and lift in the fork channels they provide intermediate the pallet base, which is glued to the topside of the blocks, and the runners, which are glued to the bottoms of the blocks.

One major problem with these prior art paper products is their significant sensitivity to moisture and humidity. Humidity significantly weakens the paper Honeycomb, and water contact can completely deform the paper Honeycomb and render it completely incapable of supporting any load at all. One attempt to solve this problem involves coating the paper with polyethylene. The coating is relatively costly, however. It also frequently fails to provide the complete sealing required to keep moisture out of the paper. Particularly as the pallet is used and the forks or other activities erode the liner, leaks can occur, water can penetrate the leaks, and the Honeycomb paper pallet can become greatly weakened and ultimately even rendered useless.

Another problem with these paper pallets is their inherent weakness from damage to exposed sides of the Honeycomb paper runners or blocks. While the Honeycomb paper is remarkably strong in compression, it has very little bending strength. The Honeycomb side walls, which extend vertically, can withstand great compression forces (axially along their length), but relatively little bending force (directed transversely at the side walls of the Honeycomb). As a result, when a support runner or block is rammed in the side by the fork of a forklift the paper Honeycomb is easily crushed and greatly weakened or even destroyed. Consequently, these types of paper pallets often are unacceptably costly not only because of the large numbers of pallets destroyed but also because of resulting damage to product being stored or shipped and the labor cost of fixing and repairing the damage to pallets and product. EP 1553025 A1 describes a paper pallet comprising a pallet base made from layers of paper sheets and having an upper face, a bottom face and first and second opposite sides, six or nine support members, each of which is mounted on the bottom face of the pallet base and has an upper end, a lower end and side surfaces extending downwardly from the bottom face of the pallet base, six U-shaped lists secured to the support members, each of said lists has an interior wall and an exterior wall, said interior wall contacting the lower end and the side surfaces of at least two of the support members. Meanwhile, based on tests made by the present inventor the use of U-shaped lists appears to be problematic, since a pallet with a destroyed U-list list is prone to collapse due to stress foldings which extend across the list.

The above mentioned prior art pallets are not sufficiently stable for being transported with forklifts.

As such, there is a need in the art for a paper pallet that provides additional strength and stability, as well as easy assembly. It is therefore an object of the present invention to develop an improved pallet that is light in weight, durable, and economical. It is an additional object to provide a pallet that will not yield splinters or exposed nails when used.

Another object is to provide a pallet that is relatively easy to assemble and manufacture, from readily available components, and recyclable as well.

A further object is to provide a paper honeycomb or similar pallet that has blocks or runners with relatively great bending resistance and strength. A still further object is to provide such a pallet that is relatively resistant to moisture and humidity.

SUMMARY OF THE INVENTION

The foregoing and other objects and advantages are attained by the present invention.

Specifically, the present invention provides a corrugated paper pallet comprising:

• a pallet base (1 ) made from one or more layers of corrugated paper sheets, said base having an upper face (1a), a bottom face (1 b), and first and second opposite sides;

• at least four support members (2), each of which has an upper end, a lower end, and side surface extending transversely downwardly from the bottom face (1 b) of the pallet base (1 ), said support members mounted on the bottom face (1 b) of the pallet base (1 ) and extending from the first side to the second side of the pallet base; and • at least four predominantly L-shaped lists (3) secured to the support members (2), each of said lists has an interior wall (3a) and an exterior wall (3b), said interior wall contacting the lower end and side surface of at least two support members,

wherein the at least four support members (2) are made from multiple layers of corrugated paper sheets, and wherein the L-shaped lists are rigid to stabilise the pallet; optionally the the L-shaped lists are water resistant.

The objective technical problem pertaining to the present invention, namely of the provision of a more stable and robust pallet, in particular compared with pallets using U-shaped lists, has been solved by the present invention with the features recited in claim 1.

Preferably the pallet of the present invention comprises six support members (2) and six L- shaped lists (3). In such a preferred embodiment the L-shaped lists (3) are spaced substantially equidistantly between the opposite sides of the pallet base.

In a particularly preferred embodiment of the present invention the support members (2) and pallet base (1 ) comprise paper sheeting or cardboard compressed or glued together.

Moreover, it is preferred that the support members have a protective moisture resistant coating, such as polyethylene. This will further prolong the lifetime of pallets of the present invention, particularly when used in humid environments.

The needs described above are largely met by the corrugated paper pallet of the present invention. The paper pallet generally comprises support members, a top sheet, and rigid water resistant L-shaped lists to stabilise the construction and protect the corrugated paper from humidity/water coming from the ground/floor on which the pallet is placed. The support members are made from laminated corrugated paper sheets. The top pad is of a corrugated material and is positioned above the support members. The support members are preferably glued onto the top pad.

The water resistant lists are preferably made from photo paper or a plastic polymer, such as polyethylene, polypropylene, PVC, PTFE, bakelit, epoxy, polystyrene, and polycarbonate. In a particularly preferred embodiment bioplastics are used, such as starch based plastic, PLA, PHB, PA 1 1 , and biodegradable polyethylene. In one embodiment the lists are made from a biodegradable plastic or other biodegradable material, as long as it provides stability to the pallet and is water resistant.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE 1 is a bottom view of a pallet according to the present invention.

FIGURE 2 is a photograph comparing U- and L-shaped lists after impact with a pallet lifter.

DETAILED DESCRIPTION OF THE INVENTION

With reference to Figure 1 , there is shown a rectangular pallet base (1 ) mounted on support members (2). The pallet base (1 ) is a corrugated sheet, while the support members are made from multiple corrugated sheets that are glued together to form the support members. The thickness of the base (1 ) varies depending on the load to be carried by the pallet. The glue used to secure each block in place is preferably polyvinyl acetate or similar glue. Referring to Figure 1 there is shown the corrugated paper pallet of the present invention, which pallet has a pallet base (1 ) made from one or more layers of corrugated paper sheets.

This base has an upper face (1 a), a bottom face (1 b), and first and second opposite sides. Support members (2) are attached to the bottom face (1 b) of the pallet base (1 ), e.g. by glueing. In order to provide stability in the pallet L-shaped lists (3) are secured to the support members (2).

Each of the support members is composed of about ten corrugated boards having the same width and attached to one another by e.g. thermo-melting glue. Shock-absorbing rib members may be disposed within corrugation of the corrugated boards for reinforcing the same. In the preferred embodiment of the present invention, there are provided six support members each of which is composed of more than 10 corrugated boards. The support members are connected under the pallet base by thermo-melting glue. In addition, each of the edges of the support members and pallet base may be sealed by thermo-melting glue to eliminate any fissure therein. An appropriate adhesive that can be used in any glueing according to the present invention is one based on aqueous vinylacetate/ethylene copolymer dispersions. In Figure 2 a photograph comparing U- and L-shaped lists after impact with a pallet lifter is shown to demonstrate the stability and robustness of a pallet having L-shaped lists compared with a pallet having a U-shaped list. The photograph compare the stability of a set of L-shaped lists attached to supporting members (L-PAL) with a U-shaped list attached to the same kind of support members (U-PAL). Importantly the L-shaped lists have been made by dividing a U-shaped list in order to establish a correct comparison.

In the example a pallet lifter was allowed to roll 5 meters from a descending ramp (10 degrees angle with horizon) before impacting with the U-PAL or L-PAL, both of which were fixed in their position. As appears from the following photograph the foldings made in the

U-PAL extend across the U-shaped list, whereas only the L-shaped list that was hit by the pallet lifter is affected, the other L-shaped list of the L-PAL being intact. Moreover, due to the greater flexibility/elasticity of the L-shaped lists the L-shaped list that was hit appears to be less affected in the area of impact than the U-shaped list in corresponding area of impact.

Moreover, for enhancing the bearing ability and collision-resistance of the pallet against a forklift, on the sides of support members may be attached several layers of carton boards to reinforce the support members.

In conclusion, the present invention has the following advantages:

• The pallet of the present invention can be recovered for reuse without causing pollution of environment.

• The pallet has much less weight so that the transfer or displacement thereof can be easily performed.

• The present pallet can be automatically mass-produced.

• After being discarded, the present pallet is subject to natural decomposition so that the environment will not be contaminated.

• The present pallet is manufactured at lower cost so that the price thereof is reduced to enhance the competitive ability of the manufacturer.

• The corrugated board may be made of recovered waste paper and can be reused so that the natural resource can be best utilized. • The support members of the present scaffold board are composed of multiple vertically arranged corrugated boards so that the vertical compression strength thereof is increased to enhance the structural strength and hardness of the pallet.

It is to be understood that the above description and drawings are only used for illustrating one embodiment of the present invention, not intended to limit the scope of the present invention. Any variation and derivation from the above description and drawings should be included in the scope of the present invention.

Claims

1. A corrugated paper pallet comprising:

• at least four support members (2) made from multiple layers of corrugated paper sheets, each of which support member has an upper end, a lower end, and side surface extending downwardly from the bottom face (1 b) of the pallet base (1 ), said support members mounted on the bottom face (1 b) of the pallet base (1 ); and

• at least four predominantly L-shaped lists (3) secured to the support members (2), each of said lists has an interior wall and an exterior wall, said interior wall contacting the lower end and side surface of the support members,

wherein the L-shaped lists are rigid to stabilise the pallet.

2. A pallet according to claim 1 including six support members (2).

3. A pallet according to claim 2 including six L-shaped lists (3).

4. A pallet according to claim 3, wherein the L-shaped lists (3) are spaced substantially equidistantly between the opposite sides of the pallet base.

5. A pallet according to any one of the preceding claims, wherein the support members (2) and said pallet base (1 ) comprise paper sheeting or cardboard compressed or glued together.

6. A pallet according to any one of the preceding claims, wherein the at least four support members have a protective moisture resistant coating.

7. A pallet according to claim 6, wherein the coating comprises polyethylene.

8. A pallet according to any one of the preceding claims, wherein the L-shaped lists are water resistant.