WO2007123548A1

WO2007123548A1 - Corrugated pallet

Info

Publication number: WO2007123548A1
Application number: PCT/US2006/015830
Authority: WO
Inventors: Duane Nelson
Original assignee: Duane Nelson
Priority date: 2006-04-26
Filing date: 2006-04-26
Publication date: 2007-11-01

Abstract

A shipping pallet compatible with fork lifts and pallet trucks is made from stamped or die cut flat corrugated board. Stringer and cross-braces form an interlocking grid work to which a top and bottom flat sheet are attached by an adhesive. The pallet may be recycled as paper and not returned to the sender. Additional reinforcement structures may be added for heavier loads.

Description

TITLE

CORRUGATED PALLET FIELD OF THE INVENTION

This invention relates to high strength recyclable corrugated pallets. BACKGROUND AND PMOR ART

Corrugated paper dates to the mid- 19^th century and corrugated paper for shipping pallets dates to the early 1970's in Japan. Most are based upon multiplying folded corrugated sheets to approximate the wooden stringers of conventional pallets. Wozniacki, USP# 5,184,558 and Hutchison, USP# 5,568,774 are representative. Such construction is suitable for most pallets used for shipping consumer items but is difficult to assemble without expensive automation and also difficult to ship in knock-down form. Corrugated pallets have many advantages. Unlike wooden, plastic, or metal pallets, corrugated can be recycled at the recipient's location as paper/cardboard and does not have to be returned for reuse. Even so called "pallet pools" ship a lot of air. Exported pallets pose two problems. Return is nearly impossible and the International Plant Protection Convention, as well as local laws in the EU, China and Australia effectively implement a ban on wood pallets which have not been certified to be fumigated by heat or pressure treatment with chemicals. Corrugated pallets, because of their processing, do not require fumigation and offer clear cost advantages in foreign shipping. There exists a need for simple corrugated pallet designs which are strong but do not require expensive multiple-step die cutting and folding steps, do not require excessive adhesive to assemble and which can be assembled at the user's site by minimally skilled laborers. BWEF DESCRIPTION OF THE INVENTION It is a first object of this invention to provide a rigid corrugated pallet for shipping and handling materials.

It is a second object of this invention to provide a corrugated pallet which can be shipped to the user in knock-down form. It is a third object of the invention to provide components for a corrugated container which require a minimal investment by manufacturers. It is a fourth object of this invention to provide a corrugated pallet which is compatible with both fork lifts and pallet trucks. A fifth object of this invention is a corrugated pallet which allows stack heights equivalent to that obtained with wood and plastic pallets conventionally in use, especially for bulky but light packaging.

These and other objects may be obtained by forming a corrugated pallet using a single die cut sheet of corrugated for each stringer; a single die cut corrugated sheet for cross-bracing; and two flat corrugated sheets for the top and bottom faces. Additional sheets may be added if needed to interdigitate with the basic stringers and cross-braces to increase load bearing capacity for heavier cases and higher stackings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a stamped flat cross-brace for a corrugated pallet.

Fig. 2 shows a stamped flat stringer for a corrugated pallet.

Fig. 3 is an exploded view showing how the stringers and cross-braces interlock.

Fig. 4 is a partial cut-away of a completed corrugated pallet.

Fig. 5 is a stamped reinforcement sheet for use in combination with a stringer and cross- brace grid.

Fig. 6 is an illustration of the insertion of a stamped reinforcement sheet into the stringer and cross-base grid.

Fig. 7 is an illustration of the reinforcement sheet inserted into the stringer and cross-brace grid. DETAILED DESCRIPTION OF THE INVENTION

An easily assembled, light weight recyclable corrugated pallet can be assembled from three stampings. The size of each stamping would change with the size of the pallet, typically in full, half and quarter-pallet sizes, based on a common 40" x 48" standard (nominally 1.0 x

1.2m). In most circumstances, industry standard single wall (double face) corrugated board may be used although double wall and tri-wall board is readily available and suitable for heavier use. It is critical that the board be cut so that the flutes in the walls are arranged in the upright or vertical orientation in both the stringers and cross-braces when viewed in the plan-view of the deck.

The type and amount of adhesive and the paper quality of the cardboard depend upon intended use. Maritime transport calls for wet strength paper and water-resistant glue. Glue guns are most convenient for applying adhesive but brushes and rollers are suitable.

Fig. 1 shows the standard pattern for a cross-brace 1. The blank 3, the length of which conforms to the short side of the pallet face, is stamped to provide cut-outs 5 to receive the walls of the stringers. Between the cut-outs, the width of the blank is reduced at 7 to avoid interference with the stringer.

Cut outs 9 are cut from the width of the blank to fold lines 11. When the blank is folded along the fold lines, the distance 13 between the fold lines 11 becomes the width of the cross-brace. The flute direction is indicated by arrow 15. The cut outs 9, where the blank is folded along the fold line, form the cut out for the tines of a fork lift or pallet truck. Stringer 21 is formed from a blank 23, the length of which conforms to that of the long side of the finished pallet. Cut outs 25 are arranged to interdigitate with the cross-braces and the space 27 between cut outs 25 are relieved to mesh with the cross-braces. Fold lines 31 are formed so that the blank may be folded to form a rectangular stringer. The flute direction is indicated by arrow 35.

When the cross-braces 2 and stringers 21 are folded along their respective fold lines and assembled as indicated in Fig. 3, a rectilinear gridwork is formed. Adhesive is then applied to the outer surfaces between the respective fold lines and flat corrugated panels applied to the adhesive. Preferably, adhesive is also applied to points of contact between cross-braces and stingers.

When the flat panels 29 and 31 have been adhered to the grid work, the result is that illustrated in Fig. 4. It is noted that the cut-outs 9, aligned, provide openings for entry of tines of a fork lift or other fork-based warehouse handling systems. Additional cut-out 33 may be present to accommodate load wheels of a pallet truck.

The pallets may be printed with a bar code or an RFID may be used to assist in tracking in a plant, warehouse or loading dock. A second reinforcing section 81 is formed from a blank 83 and notched at the sides at 85 in the same pattern as in Fig. 5. The ends 87 are cut to be the full length of the pallet while accommodating the junction of stringer and cross-bracing.

Fig. 6 is an exploded view of how the reinforcement pieces for Figs. 5 and 6 are assembled. Flat section 83 from Fig. 6 is pressed into position parallel to the stringer below the top of the flutes of stringer 21 and below cross-brace 1, with ends 87 projecting the full length of the stringers.

The assembled framework is seen in Fig 7. The space below section 83 is sufficient to form openings which will accept the tines of a forklift. A deck in the form of a flat panel 29 and a floor in the form of a flat panel 31 then are adhered to the top and bottom of the framework 89 to complete the pallet as seen in Fig. 4. Pallets of this construction have been shown to support over 6,000 pounds (2700 kg).

The invention has been described in terms of preferred embodiments, which are exemplary but not limitative of the invention. Modifications apparent to a person of skill in the art are subsumed within the purview of the invention. For recycling, the pallets may be crushed, shredded or otherwise modified for ease of shipment to a recycling plant.

INDUSTRIAL UTILITY

The corrugated pallets of this invention are easily shipped to a user in knock-down form for on-site assembly. The pallets are easily recycled and more economical than wood or plastic alternatives, especially for international commerce.

This invention has been described in terms of the preferred embodiment. Modifications and additions obvious to those skilled in the art are included within the sprit and scope of the invention.

Claims

I Claim:

1. A corrugated box structure useful as a pallet comprising: a) at least two stringers; b) at least two cross-braces; c) a flat corrugated top, and d) a flat corrugated bottom, wherein said stringers interdigitate with said cross-braces to interlock the stringers and cross-braces together before said top and said bottom are adhered in place.

2. A corrugated box structure according to claim 1 wherein said stringers and said cross- braces are cut from individual corrugated sheets and folded to align flutes of the corrugated sheets in the vertical direction.

3. A corrugated box structure according to claim 1 which consists of flat precut sheets of corrugated paper which have been pre-cut for folding and which are shipped flat to a user for assembly.

4. A corrugated box structure according to claim 1, wherein said cross-braces have cut out portions which allow the tines of a fork lift to pass through channels in a pallet.

5. A corrugated box structure according to claim 1 wherein said flat corrugated bottom has multiple cut-outs to accommodate the passage of load wheels of a pallet truck.

6. A corrugated box structure according to claim 1 further comprising a first reinforcement section having a long axis and flutes parallel to said stringers and interdigitating with the flutes of said cross-braces so as to reinforce said corrugated bottom.

7. A corrugated box structure according to claim 6 wherein said individual corrugated sheets are the same thickness.

8. A corrugated box structure according to claim 6 wherein the individual corrugated sheets have different thicknesses.