PLASTIC COMPOSITE MODULAR REBUILDABLE PALLET

Abstract

A plastic composite modular rebuildable pallet has replaceable top boards, stringers and bottom boards made from a thermoplastic resin with variable amounts of long glass fiber reinforcements molded into the pallet boards. The top boards have on center circular indexing buttons. The stringers have top lengthwise molded in channels for receiving multiple reinforcing metal bars, rods or tubes held in place by the top boards. The bottom boards have two circular cups at each end on their bottom surfaces for indexing with the on center buttons of the below pallet when the empty pallets are stacked for storage and transportation. This arrangement allows for the bottom boards to be horizontally reversibly mounted on the bottom surface of the stringers in either 180° horizontal direction. The bottom boards have thick bottom feet pads with foot wear-resistant pads for sliding engagement with ground surfaces.

Description

BACKGROUND OF THE INVENTION

The present invention relates to pallets for moving goods from place to place, and more particularly, to a plastic composite modular rebuildable pallet.

At any given time in the United States there are two billion pallets moving commercial and consumer goods from place to place. Three categories of pallets exist:

• • 1. Low cost shippers often referred to as “Nestable” pallets. These are used one way not to be returned to the original shipping company.
  • 2. Mid cost shippers often referred to as “Stackable” pallets. These are better quality that allows pallets and loads to be stacked several pallets high. These pallets are also used for one way shipment not to be returned to the original shipping company.
  • 3. High cost plastic/composite pallets often referred to as “rackable” pallets. These pallets are used in a closed loop system. They are shipped out and returned to the original shipping company for the next shipment. On average these pallets make about 15 trips per year.

Ninety five percent of the pallets used in the United States are made of wood. Plastic and composite pallets, that makes up the other five percent, are starting to take over. The rising cost of good quality clean wood and heavy weight are the main reasons. It has been reported that wood pallet manufacturing is declining while plastic composite pallet manufacturing is increasing at a rate of about 5-7 percent annually.

Although the plastic composite pallets in use today are more expensive than a similar wood pallet, the plastic pallet can last 3-4 times (more trips) longer than wood pallets thereby making the plastic pallet cost effective over time. As good as this may be, they can be improved further.

Current plastic composite pallets are made in a single piece or 2-4 pieces bonded together making them a single piece pallet. Rough handling can break a pallet board, block or stringer. If the pallet is a single piece, a broken component can make the pallet unusable.

There is a need to address these problems. A novel pallet can be made of several components such as structural boards, stringers and reinforcing members such as steel bars. The pallet should be made of plastic composite where the pallet boards and stringers are honeycombed for strength. Modular and damaged parts should be replaceable. The synthetic pallet is exceptional strong with structural board re-enforced fibers and optional metal rod reinforcements on top of the stringers within the pallet. The pallet should also have re-enforced wear resistant feet for easy sliding across ground surfaces. The pallet, when not in use or empty, should be indexably stackable for secure transportation back to the original user for next use.

SUMMARY OF THE INVENTION

A plastic composite modular rebuildable pallet has replaceable top boards, stringers and bottom boards made from a thermoplastic resin with variable amounts of long glass fiber reinforcements molded into the pallet boards. The top boards have on center circular indexing buttons. The stringers have top molded in lengthwise channels for receiving multiple reinforcing metal bars, rods or tubes held in place by the top boards. The bottom boards have two circular cups at each end on their bottom surfaces for indexing with the on center buttons of the below pallet when the empty pallets are stacked for storage and transportation. This arrangement allows for the bottom boards to be reversibly mounted on the bottom surface of the stringers in either 180° horizontal direction. The bottom boards have thick bottom surfaces with foot wear-resistant feet pads for sliding engagement with ground surfaces.

A principle object and advantage of the present pallet is its repeatable use and easy replacement of boards and stringers to further insure long continued use.

Another object and advantage is that the pallet may be custom made in sizes from 20″×28″ or 40″×48″ or 60″×85″ or any suitable size for the intended end use. The top boards are suitably 6″ wide, the bottom boards 4″ wide, both being ⅞″ thick. The stringers are 5″ wide, 48″ long and 4″ high with bottom forklift carve outs for receiving the tangs of a fork lift.

Another object and advantage is that the pallet boards and stringers may be made of polypropylene thermoplastic resin but could also could also be molded with other thermoplastic resins such as polyethylene, nylons, PVC (polyvinyl chloride), or polyesters.

Another object and advantage is that the pallet boards may be re-enforced with molded in carbon fibers, graphite fibers, basalt fibers or ceramic fibers varied from 20% to 50% of total volume to resist bending and breaking from impacts.

Another object and advantage is that the bottom pallet boards may be made with molded in wear-resistant pads for long term sliding engagement with ground surfaces.

Another object and advantage of the present pallet is that the 4″ wide pallet bottom boards may be assembled onto the stringers in either direction (180° of bottom board horizontal rotation). The bottom boards on their bottom surface advantageously have two side by side circular cups each 1½″ from one of the side edges as to assure at least one of the cups will be indexable with the singular top board 3″ on center button on the 6″ wide top boards to keep the empty pallets from sliding when stacked upon one another.

Another object and advantage of the present pallet is that the present pallet can last 3 to 4 time (more trips) longer than the prior wood pallets making the present pallet cost effective over time.

Another object and advantage of the present pallet is that the cost of good quality wood, cleanliness and heavy weight are the main reasons. Wood pallet manufacturing is declining while plastic composite pallet manufacturing is increasing at a rate of about 5-7 percent annually.

Another object and advantage of the present pallet is that it is modular and reparable with screwed together boards and stringers rather than other prior plastic pallets which are made in a single piece or 2-4 pieces bonded together making them a single piece pallet. Rough handling can break a pallet board, block or stringer. If the pallet is a single piece, a broken component can make the whole pallet unusable.

Another object and advantage of the present pallet is that the pallet stiffness in the direction of the stringer length is required in most pallet applications. The degree of stiffness is variable depending on how the end user intends to use the pallet. The present stringer design is made with 3 molded in channels in its top surface running in the long direction. These channels are sized so that steel bars can be inserted into them prior to attaching the top composite structural boards. The top composite structural boards firmly hold the steel bars, rods or tubes firmly in place. Up to 3 steel bars per stringer can be inserted. The number of steel bars used will determine the stiffness performance of the pallet in the stringer length direction.

Another object and advantage of the present pallet is that pallet boards and stringers are light in weight while maintain structural strength as the hollow undersides are re-enforced with honeycombed, gusseted, waffled, webbed or ribbed designs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a right front top perspective view of the plastic composite modular rebuildable pallet of the present invention;

FIG. 2 is a left front bottom perspective view of the present invention;

FIG. 3 is a front elevational view of the present invention;

FIG. 4 is a right or left side elevational view of the present invention;

FIG. 5 is a top perspective view of one of the top boards partially broken away;

FIG. 6 is a bottom perspective view of one of the top boards;

FIG. 7 is top perspective view of one of the stringers;

FIG. 8 is a top plan view of one of the stringers;

FIG. 9 is a top plan view broken away of one of the stringers with channels holding a metal reinforcement bar, rod or tube therein;

FIG. 10 is a top plan view partially broken away of one of the stringers with channels holding two metal reinforcement bars, rods or tubes therein;

FIG. 11 is a top plan view partially broken away of one of the stringers with channels holding three metal reinforcement bars, rods or tubes therein;

FIG. 12 is a cross sectional view partially broken away of an assembled pallet showing three steel reinforcement bars therein as if taken along lines 12-12 of FIG. 11;

FIG. 13 is a stringer left or right side elevational view;

FIG. 14 is a top perspective view of a bottom board;

FIG. 15 is a right or left side elevational view of one of the bottom boards;

FIG. 16 is a bottom perspective view of one of the bottom boards;

FIG. 17 is left side elevational view partially broken away showing bottom board cup A indexed with the top board button; and

FIG. 18 is left side elevational view partially broken away showing bottom board rotated 180° showing bottom board cup B indexed with the top board button.

DETAILED DESCRIPTION

In general the plastic composite modular rebuildable pallet 10 of the present invention may be viewed and understood with reference to FIGS. 1-4. Pallet 10 is made of nine composite structural top and bottom boards 14 and 36, respectively, and three plastic molded stringers 24. These 12 molded pallet components are held together with screws 22 and 48. This modular pallet 10 can easily be taken apart so that broken components can be replaced thereby making the pallet useful again. This modular feature eliminates the repairability problems associated with wood and one piece plastic pallets in use today. All Top composite structural boards 14 are on the same plane and parallel. The bottom composite structural boards 36 are on a second plane and parallel with each other and parallel with the top composite structural boards 14. All composite structural boards 14 and 36 are perpendicular to the plastic molded stringers 24. The pallet 10 dimensions can be custom made to meet the end users exact size and strength requirements (20″×28″; 40″×48″ or 60″×85″ for example).

The top and bottom boards 14 and 36 and stringers 24 are molded with polypropylene thermoplastic resin and long glass fiber reinforcements. It should be understood that the top boards could also be molded with other thermoplastic resins such as polyethylene, nylons, PVC, polyesters, etc. In addition, the bottoms of the top, bottom boards 14 and 36 and stringers 24 are gusseted, waffled, webbed or ribbed 16, 45 and 34 respectfully to further add strength. The long glass fiber reinforcement can also be of carbon fiber, graphite fiber, basalt fiber, ceramic fiber etc. The amount of long fiber reinforcement in the top and bottom boards 14 and 36 can be varied from 20% to 50% of pallet volume. Increasing the long fiber reinforcement percentage improves the pallet's 10 ability to resist bending and breaking from impacts. This variability allows the user to custom tailor a pallet to their exact performance requirements.

Referring to FIGS. 5 and 6, the top board 14 may be 6″ wide, 40″ long and ⅞″ thick. Screw bosses 20 are re-enforced to receive twelve mechanical fasteners, bolts or screws 22 which may be #9 2.5″ torque-type drive screws for securement to the stringers 24 at the twelve stringer screw bosses 26. On top of the upper boards 14 are located 3″ on center three circular indexing buttons, tabs or pucks 18 which will be appreciated later herein.

Referring to FIGS. 2, 3, 7-12, the three stringers 24 may be appreciated. Illustratively, the stringers are 5″ wide, 48″ long and 4″ high with twelve top and twelve bottom screw bosses 26. The bottom side of the stringers 24 are also gusseted 45 for additional strength. Longitudinally in the central top of the stringers 24 are three molded in channels 30. As seen in FIGS. 9-11, up to three steel bars, rods or tubes 32 generally ½″ wide, 1′ deep and 48″ long and may be made of 18, 16, 14 or 12 gauge thickness. Depending on the pallet 10 strength requirements, one to three of the bars, rods or tubes 32 may be placed into the channels 30 perpendicular to the top and bottom boards 12 and 36 to add pallet strength running perpendicular to top and bottom boards 14 and 36 and such are held thereat by the screw secured top boards 14. Also the stringers 24 have bottom fork lift carve outs 35 for the tangs of a fork lift. Thus the pallet 10 may be lifted up from its front/back or its sides.

Referring to FIGS. 2, 14, 15 and 16, the bottom boards 36 of the pallet 10 may be seen and understood. Bottom boards 36 are generally 4″ wide, 40″ long and ⅞″ thick with screw bosses 38 for twelve screws 40 to secure the bottom boards 36 to the stringer 24. Opposite to the stringer 24 mounting surfaces each bottom board 36 has three feet wear pads 50 to provide wear surfaces for when the pallet 10 is slid across a floor surface. Where otherwise the pallet will become worn out more quickly. The bottom of the bottom board 36 is also gusseted 45 for additional strength.

Referring to FIGS. 17 and 18, the bottom side of each of the bottom boards 36 on pads 50 have three pairs of side by side two circular depressions or cups 44A and 44B generally each 1½″ from either side edge. By this arrangement, the bottom boards 36 may be horizontally secured with screws 40 to the stringer in either direction A or B which amounts to a 180° arrangement (see FIG. 14). This assures that one of cups 44A or 44B will always be lined up with the button 18 on the top board 14 when the empty pallets 10 are stacked on top of each other for return to the sender. With this indexing, the pallets 10 are not prone slide off each other when empty and stacked upon one another. Also when the pallets are assembled for use, no care need be given as to whether the bottom boards 36 are rotated in either position to be fastened to the stringers 24.

The above description and accompanying FIGS. are for illustrative consideration and the true scope of this pallet 10 invention are to be determined by the following claims.

Claims

1. A plastic composite modular rebuildable pallet comprising: a) replaceable top boards;b) replaceable bottom boards with wear-resistant feet pads for engagement with below surfaces;c) replaceable stringers running 90° from the boards; andd) mechanical fasteners for holding the top and bottom boards to the stringers.

2. The pallet of claim 1, wherein the bottom sides of the top and bottom boards and the stringers are honeycombed on their bottom sides to add additional strength the pallet.

3. The pallet of claim 1, wherein the bottom boards are 180° horizontally reversible when mounting to the stringers.

4. The pallet of claim 1, wherein the top and bottom boards have re-enforcing fibers molded into the boards and stringers running their lengths.

5. The pallet of claim 4, wherein the re-enforcing fibers may be chosen from a group comprising carbon fibers, graphite fibers, basalt fibers or ceramic fibers.

6. The pallet of claim 4, wherein the re-enforcing fibers may be 20-50% of volume of the boards.

7. The pallet of claim 1, wherein the top and bottom boards and stringers may be chosen from a group comprising thermoplastic resins such as polypropylene, polyethylene, nylons, PVC, or polyesters.

8. The pallet of claim 1, wherein the top boards have top surfaces with circular indexing buttons and the bottom boards have circular indexing cups to index into a second lower pallet top indexing buttons.

9. The pallet of claim 1, wherein the stringers have top surfaces with channels for locating reinforcing metal bars, rods or tubes held in place by fastened top boards.

10. A plastic composite modular rebuildable pallet comprising: a) replaceable honeycombed top boards with molded in re-enforcing fibers;b) replaceable, horizontally rotatable, honeycombed bottom boards with wear-resistant feet for engagement with ground or below surfaces with molded in re-enforcing fibers wherein the bottom boards are 180° horizontally reversible when assembling the pallet;c) replaceable honeycombed stringers running 90° from the boards with molded in re-enforcing fibers; andd) mechanical fasteners for holding the top and bottom boards to the stringers.

11. The pallet of claim 10, wherein the re-enforcing fibers may be chosen from a group comprising carbon fibers, graphite fibers, basalt fibers or ceramic fibers.

12. The pallet of claim 10, wherein the re-enforcing fibers may be 20-50% of volume of the boards.

13. The pallet of claim 10, wherein the top and bottom boards and stringers may be chosen from a group comprising thermoplastic resins such as polypropylene, polyethylene, nylons, PVC, or polyesters.

14. The pallet of claim 10, wherein the top boards have top surfaces with indexing buttons and the bottom boards have indexing cups to index into a second lower pallet top indexing buttons.

15. The pallet of claim 10, wherein the stringers have top surfaces with channels for locating reinforcing metal bars, rods or tubes held in place by fastened top boards.

16. A plastic composite modular rebuildable pallet comprising: a) replaceable honeycombed top boards with molded in re-enforcing fibers;b) replaceable, horizontally rotatable, honeycombed bottom boards with wear-resistant feet for engagement with ground or below surfaces with molded in re-enforcing fibers wherein the bottom boards are 180° horizontally reversible when assembling the pallet;c) replaceable honeycombed stringers running 90° from the boards; andd) mechanical fasteners for holding the top and bottom boards to the stringers.

17. The pallet of claim 16, wherein the re-enforcing fibers may be chosen from a group comprising carbon fibers, graphite fibers, basalt fibers or ceramic fibers.

18. The pallet of claim 16, wherein the re-enforcing fibers may be 20-50% of volume of the boards.

19. The pallet of claim 16, wherein the top and bottom boards and stringers may be chosen from a group comprising thermoplastic resins such as polypropylene, polyethylene, nylons, PVC, or polyesters.

20. The pallet of claim 16, wherein the top boards have top surfaces with indexing buttons and the bottom boards have indexing cups to index into a second lower pallet top indexing buttons.

21. The pallet of claim 16, wherein the stringers have top surfaces with channels for locating reinforcing metal bars, rods or tubes held in place by fastened top boards.

22. A plastic composite modular rebuildable pallet comprising: a) replaceable honeycombed top boards with molded in re-enforcing fibers;b) replaceable, horizontally rotatable, honeycombed bottom boards with wear-resistant feet for engagement with ground or below surfaces with molded in re-enforcing fibers wherein the bottom boards are 180° horizontally reversible when assembling the pallet, wherein the top boards have top surfaces with indexing buttons and the bottom boards have indexing cups to index into a second lower pallet top indexing buttons;c) replaceable honeycombed stringers running 90° from the boards with molded in re-enforcing fibers, wherein the stringers have top surfaces with channels for locating reinforcing metal bars, rods or tubes held in place by fastened top boards; andd) mechanical fasteners for holding the top and bottom boards to the stringers.

23. The pallet of claim 22, wherein the re-enforcing fibers may be chosen from a group comprising carbon fibers, graphite fibers, basalt fibers or ceramic fibers.

24. The pallet of claim 22, wherein the re-enforcing fibers may be 20-50% of volume of the boards.

25. The pallet of claim 22, wherein the top and bottom boards and stringers may be chosen from a group comprising thermoplastic resins such as polypropylene, polyethylene, nylons, PVC, or polyesters.

26. A plastic composite modular rebuildable pallet comprising: a) replaceable top boards;b) replaceable bottom boards with wear-resistant feet pads for engagement with below surfaces;c) replaceable stringers running 90° from the boards, the stringers having top surfaces with channels for locating at least three reinforcing metal bars, rods, or tubes; andd) mechanical fasteners for holding the top and bottom boards to the stringers.