CA2142050A1 - Pallet construction - Google Patents

Abstract

A pallet construction includes a rectangular bottom frame with at least four bottom members, corner blocks located at least at the various corners of the bottom frame and attach thereto, stringers extending from the tops of the corner blocks at the ends of two opposed bottom members, and a plurality of boards extending transversely between the stringers to provide a platform adapted to support a load.
All of the members of the pallet construction are made from a thermoplastic-based material.

Description

- 21420~0 IMPROVED PALLET CONSTRUCTION
This invention relates generally to pallets of the kind used for shipping boxes,containers and other items.
BACKGROI~ND OF THIS INVENTION
Cu~lelllly, the shipping industry utilizes pallets of various si_es, mostly m~mlfactllred from rough wooden boards, upon which the objects to be shipped canbe piled and then shrink-wrapped together with the pallet.
A typical such pallet, seen in plan view, has dimensions of anywllele from 36"
x 40" up to a square measuring 48" on a side. The most popular si_e is a rect~ngle me~llring 40" x 48".
The simplest conventional pallet is m~nllf~ctllred from rough boards approximately 1" x 4" in cross-section. Typically, three such boards are placed in parallel and set on their edges to provide the beam strength of the pallet. These may be called "stringers". A number of additional boards are then lltili7-~d, flat-side down, to provide "planks" extending at right angles to the stringers and nailed into place. The spacing between the stringers is sufficient to allow entry of the two tines of a fork-lift truck, by which the palletized load is to be manipulated. For greater strength, it is common to provide additional "planks" at the bottom of the pallet, also running at right angles to the stringers, and also nailed in place.
It will be appreciated that the above-defined construction allows the fork of a manual pallet truck to enter the pallet only at two opposed sides. The stringers prevent fork entry from the other two sides.
To permit full four-way entry, a more recent "block" design utili7ing wooden boards involves a construction in which the edgewise stringers are replaced by flat-wise stringers under the upper planks, and wherein 3" x 4" blocks are provided under the flat-wise stringers at the ends and in the middle. Additional flat-wise boards are placed under the blocks, typically providing a "frame" configuration with an additional bottom stringer extending along the middle of the pallet. Again, all such boards are nailed in place.
One of the major disadvantages of a wooden pallet, regardless of the construction utili7.ocl, is a limitation on the number of times it can be re-used before it requires repair. For example, including h~n-lling within a warehouse, the average , 2l42ns~

number of trips for a wooden pallet is about one hundred and thirty-nine, which corresponds to less than one year of use.
Other disadvantages of the current wooden pallets include: limited water reSi~t~nre~ minim~l ch~mir~l re~i~t~nre, minim~l bacteria lcsi~ e, prone to attack by t~ es or fungus, prone to develop splinters, and must be nailed together.
S~ m~times the components work loose and cause damage to the product. Also, the wooden pallets have a limited recyclability and are difficult to dispose of.
In view of the fol~going shollcollli~ of the conventional wooden pallet, it is an object of one aspect of this invention to provide a light-weight pallet m~m-f~ red from an extruded mixture of thermoplastic material and shredded wastematerials such as recycled plastic obtained from local municipal recycling facilities, and to fasten the various components together without the use of nails or other metallic fasteners.
Such plastic pallets, though somewhat more e~ensive to m~mlf~rtllre than the returnable wood pallets or the one-way wood pallets, would have a lifetime estim~tto~
to be between four and five times as long as the best conventional wooden pallets, for example up to five years of useful life compared to one year for wood.
The plastic pallet proposed herein would also be 100% recyclable at the end of its useful life, and thus would have no negative environmental impact.
The pallet provided herein would also elimin~te disposal costs for pallet users.Wood pallets have been banned from many landfill sites, making disposal difficult.
Sites that continue to accept old wood pallets can charge $150.00 per ton or $3.00 per pallet.
Finally, the pallet proposed herein will be engineered and designed to approximate the properties of wood pallets, and be capable of passing the testing specified by ASTM D1185 testing protocol.
SUMMARY OF THIS INVENTION
More particulary, this invention provides a pallet construction comprising:
a rectangular bottom frame including four bottom members constructed of a thermoplastic-based material, four corner blocks constructed of thermoplastic-based material, each corner block being disposed above the bottom frame and being attached to the frame at one of its ~l42n~0 corners by virtue of being fastened to both of the bottom members which define the respective corner, two stringers constructed of thermoplastic-based material, one said stringer e~Lelldhlg between and being f~ct~nPd to the tops of the corner blocks at the ends of 5 one bottom member, the other said stringer extending between and being fa~ten~d to the tops of the corner blocks at the ends of the bottom member opposite said onebottom member, and a plurality of boards constructed of thermoplastic-based material, said boards extending between the stringers to provide a platform adapted to support a load,10 wherein the vertical separation between the stringers and the bottom members below the stringers is sufficient to permit entry of the tines of a fork-lift truck.
In a particular but non-limitin~ embodiment, this invention provides a pallet construction comprising:
a rectangular bottom frame defined by four outside bottom members and one 15 interm~ t~ bottom member, the four outside bottom members consisting of a first pair of opposed bottom members and a second pair of opposed bottom members, the interm~rli~te bottom member extending subst~nti~lly centrally between said first pair of opposed bottom members, nine spacer blocks, including three spacer blocks disposed above and secured to the 20 ends and the middle, respectively, of one of said second pair of opposed bottom members, another three spacer blocks disposed above and secured to the ends and the middle, respectively, of the other of said second pair of opposed bottom members, and a further three spacer blocks disposed above and secured to the ends and themiddle, respectively, of said interm~ te bottom member, each block except those 25 located at the middle of the respective bottom members being fastened to both of the bottom members which converge to define the respective locations of the block in question, a first stringer extending between and being fastened to the tops of the spacer blocks at the ends and the middle of one of said second pair of opposed bottom members,30 a second stringer extending between and being fastened to the tops of the spacer blocks at the ends and the middle of the other one of said second pair of opposed bottom members, and a third stringer extending between and being fastenéd to the 21~20~0 .,~

tops of the spacer blocks at the ends and the middle of said interme~ te bottom member, and a plurality of boards supported on and ext~-n~ing between the ~llhlgel. to provide a platform adapted to support a load, 5 the vertical sepaldlion between the stringers and the bottom members below theingel~ being sufficient to permit entry of the tines of a fork-lift truck, wherein substantially all bottom members, spacer blocks, ~ gels and boards are constructed from thermoplastic-based material.
BRIEF DESCRIPTION OF THE DRAWINGS
Several embodiment of this invention are illustrated in the accompanying drawings, in which like numerals denote like parts throughout the several views, and in which:
Figure 1 is a plan view of a plastic pallet constructed in accordance with this invention;
Figure 2 is an end elevational view of the pallet of Figure l;
Figure 3 is a side elevational view of the pallet of Figure l;
Figure 4 is a cross-sectional view through a rectangular tube utilized for the spacer blocks in the plastic pallet of Figure l;
Figure 5 is a cross-sectional view through a typical extruded plastic board for utilization in the plastic pallet of Figure l;
Figure 6 is a plan view of a spacer block in accordance with a further embodiment of this invention;
Figure 7 is a cross-section through an extrusion suitable for providing the boards and stringers used in the construction of the pallet;
Figure 8 is a view similar to Figure 7 showing an alLellla~ e cross-section;
and Figure 9 is a perspective, exploded view of the major components of the pallet of this invention.
DETAILED DESCRIPTION OF THE DRAWINGS
The basic novelty of this invention lies in the provision and configuration of price and perfollllance c- lllpe~ e plastic pallets using recycled plastic obtained from local MURFs (Municipal Recycling Facilities). While such plastic pallets could be 21~20~0 s injection moulded, it is prefelled to utilize extruded "boards" of recycled plastic and to assemble the boards together to form the pallets. Injection moulding is particularly limited in that each size of pallet would require a separate mould that could cost anywhere up to $500,000.00, along with an injection moulding press costing upwards S of two million dollars. By contrast, the total cost ~ltili~ing the extrusion method but excluding any welding fixture (if required) would be less than $25,000.00. The basic extrusions can easily produce any size pallet required, for example the popular 40"
x 48" size, or alternatively 48" x 48", or 36" x 40". The length of the extrudedboards can be adjusted by simply rh~ngi~,g the flying cut-off saw at the extruder.
It will be understood that the use of plastic and other material that would otherwise go to landfill solves the major environmental problem of wood pallets. By extruding "boards" from recycled plastic and by joining the boards together either by welding or adhesives, a pallet can be produced that appears similar to a conventional wood pallet, thus reducing market resi~t~n~-e to a novel product.
Attention is now directed to Figures 1, 2 and 3, in which a pallet is shown generally at 10, and includes a plurality of planks or boards 12 arranged with the wide side horizontal and secured to three stringers 14, 15 and 16 which are in parallel and are also arranged with the wide side horizontal. As can be seen best in Figure 1, the external stringers 14 and 16 are eq~ t~nt from the middle ~llhlger 15, with the stringers 14 and 16 defining the outer edges of the pallet 10.
Located under and adjacent either end of each of the stringers 14, 15 and 16 are short lengths of an extruded hollow "block" material, the end blocks being identified by the numerals 18 and 20. Located under the middle of each of the stringers 14, 15 and 16 are shorter blocks 22 (visible only in Figure 3).
Finally, the illustrated pallet 10 includes a "picture frame" configuration of flat bottom members under the blocks 18, 20 and 22, specifically including four members extending around the periphery of the pallet 10. Even more particularly, the picture frame includes two end members 25 (located directly under the end upper boards 12a and 12b in Figure 1), and two further members located directly under the lateMI
stringers 14 and 16, as pictured in Figure 1. The leftward one of these bottom lateral members is identified by the numeral 27 in Figure 3.
A further bottom member lies directly under the central stringer 15 in Figure 21~205U

1, but is not visible in any of the figures.
Attention is now directed to Figure 4, which illustrates a cross-section throughan extrusion suitable for providing the blocks 18, 20 and 22. The block 20 is rectangular, has subst~nti~lly uniform wall thi~1rn~ss, and has rounded corners.In Figure 5, a possible cross-section for an extruded bottom member 12 is illustrated. It will be seen that the extrusion includes four internal partitions 30 spa,.l-i"g between a top wall 32 and a bottom wall 34. End walls 36 complete themember 12. It will be noted that the extruded member 12 has rounded corners.
In Figure 5, a small circled portion of the top wall 32 has been m~gnifi~cl at Figure Sa, from which it will be seen that, as an option, the outer surface of the top wall 32 may be provided with parallel channels 38, distributed over the entire upper surface. The ch~nn~ls 38, which may preferably be provided on the top and bottomsurfaces of all boards, stringers and spacer blocks, have several functions. Firstly, they provide an improved frictional grip between the pallet and a floor upon which the pallet is resting. Secondly, they facilitate induction welding of the various pieces together by allowing a greater degree of contact belween the mating surfaces, since they provide channels along which heated air can escape without becoming trappedbetween the surfaces.
In addition to induction welding, the components may be secured together by sonic welding, vibrational welding, hot plate welding or ferrous oxide inductionwelding. It may also be possible to utilize adhesives in the form of a coating or an impregnated tape.
It is preferable to use a non-m~tallic method for joining the components together (i.e., some method other than nailing), in order to minimi7~ difficulties in recycling the pallets after their useful life is over.
Utilizing the construction described above, it is considered possible to produce a 40" x 48" pallet, able to stack five pallets high, each pallet supporting a weight of 2,800 pounds and able to be racked in drive-through racks with minim~l deflection.

It is contemplated to use fibreglass fibres for reinforcement of the various extruded portions. The employment of fibreglass fibres has the ecological advantage of utili7ing fibreglass waste which is cullclllly being sent to landfill.

214205~
-The economics of this procedure may require a vertically integrated process that takes in waste and does all required processing in house. Such a waste-to-fni~h~d product process is another unique feature of the present invention. Rec~llse MURF material tends to be co~ lilul~d with oils and metals, it will require proper S shredding, washing and sorting by m~çh~ni-~l and/or hydraulic means prior to use.
Since the polyethylenes are lighter than water they will float, whereas the poly~r~ylenes will sink. The sorted material will then be dried and flaked and proportionally mixed in the extruder. The water used to wash the material will of course have to be treated, neutralized and subjected to solid removal, so that the water can be recycled.
AKention is now directed to Figure 6, which shows a modified spacer block 50, seen in plan view. It will be noted that, whereas in the first embodiment illustrated in Figures 1-5, the spacer blocks are disposed with their central openil1g holi~ontal, the spacer block 50 seen in Figure 6 has a plurality of central openings which are vertically disposed.
More specifically, the spacer block 50 has the general shape of a rectangular parallelepiped with rounded vertical edges 52, and having four vertical outside walls 54 defining an internal chamber, the laKer being divided up by the plesel1ce of two longitll-lin~l, vertical, interm~ te partitions 56 parallel to the longer walls 54 of the spacer block, and five transverse, vertical, interme~i~te partitions 58, 59, 60, 61 and 62, all of which cross the longit~ in~l partitions 56. Note further that the outer longer walls 54 have a V-shaped intermP~ te indent 64, located at either end of the trar.sverse partition 60.
It will be understood that the provision of the internal partitions 56 and 58-62increases the stability of the spacer block under load, and provides material pdlllwdys through which impact or crushing energy can be dissipated and distributed to other members.
Attention is now directed to Figure 7, which shows a first variant of the cross-section of the extrusion from which the boKom members, the stringers and the boards can be manufactured. It is pointed out that the extrusion has a width (horizontal) several times as great as its depth (vertical dimension), and is an integral structure which includes a top wall 70, a boKom wall 72 spaced below the top wall 70, and two 21~205~

edge walls 74 bridging between the top and bottom walls 70 and 72 to define an internal volume, the volume being partitioned into a plurality of isolated cells 76 by a plurality of upright partitions 78 which are integral with the top and bottom walls 70 and 72 of the extrusion.
It is particularly to be noted in Figure 7 that the bottom wall 72 of the extrusion incorporates four ouLwaldly projecting ribs 80, between which are located channels 82.
In order to cooperate with the non-planar surface shown on the bottom wall 72 of the cross-section of Figure 7, the spacer blocks 50 are preferably injection moulded in such a way as to incorporate the "negative" of the rib and channel arrangement seen in Figure 7, whereby a board or stringer cut from the extrusionseen in Figure 7 can be laid upon the spacer block in such a way that a rib on the extrusion will register with a groove on the spacer block, and vice versa. This registry of colles~ollding non-planar surfaces will combine well with a number of - 15 adhering techniques, to provide a joint which is highly resistant to fracture, rupture or separation, and which is particularly strong in the direction at right angles to the direction of the ribs. A suitable process can be one selected from the group consisting of: induction welding, sonic welding, vibrational welding, hot plate welding, ferrous oxide induction welding, the application of an adhesive, and the utilization of an impregnated tape.
Attention is now directed to Figure 8, which illustrates a further variant of the cross-section suitable for making the various elongate members of the pallet construction. Specifically, it is seen that the extrusion 100 in Figure 8 is an integral structure which includes a top wall 110, a bottom wall 112 spaced below the top wall 110, and two edge walls 114 bridging between the top and bottom walls 110 and 112 to define an interior volume which is partitioned into a plurality of isolated cells 116 by a plurality of upright partitions 118 integral with the top and bottom walls 110 and 112 of the extrusion 100.
It is particularly to be noted in Figure 8 that the bottom surface of the bottomwall 112, instead of being provided with alLell~hlg ribs and channels of generally rectangular section, has a fine-scale sawtooth configuration in section, consisting of a plurality of side-by-side, V-shaped ridges 120. This particular configuration allows 21420~ D
_ a large number of point or line contacts with another member, which is particularly advantageous when using induction welding, sonic welding or vibrational welding as the fastening process. Again, as with the variant shown in Figure 7, the spacer blocks 50 could be injection moulded to provide a surface that will mate with orS extend transversely to the sawtooth ridges illustrated in Figure 8.
Figure 9 is self-explanatory, and is a perspective, exploded view of a portion of a pallet constructed in accordance with this invention. Four bottom members 127, 128, 129 and 130 define a rectangular frame having four corners, at each of which a spacer block 50 is located. Two stringers 114 and 116 are located so as to extend between and rest atop the blocks 50 at the ends of the bottom members 128 and 130, respectively. Finally, a plurality of parallel lateral boards 112 extend between the stringers 114 and 116 and are secured thereto.
It should be noted, for all embodiments and variants of the various components of this invention, that the vertical depth of the space blocks 20, 50 defines the vertical "allowance" for the entry of the tines of a fork-lift truck, when the fork-lift is approaching the pallet in a direction parallel with the uppermost boards.
Preferably, the thermoplastic-base material from which the pallet construction is manufactured consists of a matrix of thermoplastic material, together with at least one filler selected from the group conci~ling of: glass fibers, shredded thermosetting material, mica.
It will further be understood that the particular horizontal cross-sectional view of the pallet 50 in Figure 6 can have other possible shapes. It is considered that the verticality of the outer walls 54 is more important than the specific cross-sectional shape, which may be triangular, lecla~ lar, pentagonal, etc. It is also considered that the particular disposition and thir1~nPss of the internal partitions 56 and 58-62 is not as important as their vertical orientation. The verticality of the various parts of the spacer block ensures maxirnum load-bearing capability.
In su~ llal~, there has been provided herein a pallet construction which utilizes 100% reprocessed andtor recycled materials, applopliately made into continuous length components or "boards" through a process such as extrusion, but not limited thereto. The boards can then be cut into required lengths for the assembly into the ~mal product. Some of the components referred to in the previous 2142n~
-description, for example the spacer blocks, will be m~mlf~ctllred from materials which can be i~Pntir~l to or compatible with the materials from which the "boards"
are extruded. However, it is believed advantageous to injection mould the spacer blocks, due to the fact that at least some of its space blocks must contact more than S one board or stringer, in many cases l~l"l~ing at right angles to each other, thus requiring accommodation to ribs or sawtooth ridges l~ ning in mlltu~lly perpen~liclll~r directions.
The physical properties and perfoll~lallce char~cteri~ti~s of the pallet described earlier can be adjusted or modified by several methods, including, but not limited to, 10 changes in materials, changes or modifications to the additives or fillers incorporated in the construction, modifying the geometry(s) of the components used, and modifying the quantities of components used in the fabrication of the pallet.
Although the final product described earlier is a pallet which is defined as a "four way entry" pallet, minor changes to the assembly combinations or orientations 15 or geometries could result in a "one way" or "two way entry" pallet.
This invention includes both a "block" type and a "stringer" type pallet, the differentiation reslllting from ch~nging the orientations of the assembled boards and blocks in the final product. The present invention accomplishes this design flexibility without the major disadvantage of high tooling costs. The design inflexibility which 20 is associated with the current injection moulded or thermal formed plastic pallets in the marketplace is elimin~trd Unlike current plastic pallets in the lllalkel~lace, this invention can be modified to meet a varied number of durability levels and market applications with changes such as, but not limited to, adjustments in the board wall thirl~n~ss, rib 25 configurations, fillers and/or additives used, and/or simple changes in the number of boards and riser blocks used.
Unlike current plastic pallets in the marketplace, design considerations such as impact performance, "slip" resistance and designrd deck friction can be modified by effecting simple adjustments in the surface materials used.
This invention has additional novelty and utility in the design considerations of specialty applications. Such applications include those requiring sterilization or uses in anti bacterial ell~holllllents. This is a distinct advantage over current wood 2l~2n~
ll pallets.
Turning briefly to the question of adjusting the surface characteristics of a board of stringer, it will be appreciated that the method described earlier (extruding the specific surface configuration, whether rib/channel or sawtooth) is not the only 5 option available. Another way to obtain changes in the surface characteristics of an extruded board is to emboss one or both surfaces shortly after extrusion (probably while the extrusion is still hot) by lltili~ing one or more rollers engraved with a suitable pattern to be i,l,pressed on the surface of the extrusion. A second process is to apply a specific l~min~tion of a dirrerelll material against one of the flat, wide 10 surfaces of the extrusion, and to adhere or otherwise secure the l~min~tion in place.
Alternatively, it is possible to co-extrude two different materials from the same extrusion die, thereby obtaining different surface characteristics.
Finally, it is to be understood that the provision of the internal partitions 56and 58-62 in the spacer block 50 accomplishes the following ends: a) increases the 15 overall surface area of contact for the assembly process of the spacer blocks to the other elements, b) improves the design flexibility of the welded or bonded interface between the spacer block and the other components, c) provides assistance for locating the components for the assembly process, d) functions as a stress distribution mechanism at the spacer blocks, to disperse the mechanical system stresses which20 result from such field requirements as lift truck fork impact, twisting and/or shear or other stresses which result from normal field use, and e) provides a secure interlocking of two mated surfaces (in the case of the rib-and-channel configuration) wh.~h increases the shear strength of the assembly.
While several embodiments of the present invention have been illustrated in 25 the accompanying drawings and described hereinabove, it will be evident to those skilled in the art that changes and modifications may be made therein, without departing from the essence of this invention as set forth in the appended claLms.

Claims (15)

1. A pallet construction comprising:
a rectangular bottom frame including four bottom members constructed of a thermoplastic-based material, four corner blocks constructed of thermoplastic-based material, each corner block being disposed above the bottom frame and being attached to the frame at one of its corners by virtue of being fastened to both of the bottom members which define the respective corner, two stringers constructed of thermoplastic-based material, one said stringer extending between and being fastened to the tops of the corner blocks at the ends of one bottom member, the other said stringer extending between and being fastened to the tops of the corner blocks at the ends of the bottom member opposite said onebottom member, and a plurality of boards constructed of thermoplastic-based material, said boards extending between the stringers to provide a platform adapted to support a load,wherein the vertical separation between the stringers and the bottom members below the stringers is sufficient to permit entry of the tines of a fork-lift truck.

2. The pallet construction claimed in claim 1, in which the thermoplastic-based material consists of a matrix of thermoplastic material, together with at least one filler selected from the group consisting of: glass fibres, shredded thermosetting material, mica.

3. A pallet construction comprising:
a rectangular bottom frame defined by four outside bottom members and one intermediate bottom member, the four outside bottom members consisting of a first pair of opposed bottom members and a second pair of opposed bottom members, the intermediate bottom member extending substantially centrally between said first pair of opposed bottom members, nine spacer blocks, including three spacer blocks disposed above and secured to the ends and the middle, respectively, of one of said second pair of opposed bottom members, another three spacer blocks disposed above and secured to the ends and the middle, respectively, of the other of said second pair of opposed bottom members, and a further three spacer blocks disposed above and secured to the ends and themiddle, respectively, of said intermediate bottom member, each block except those located at the middle of the respective bottom members being fastened to both of the bottom members which converge to define the respective locations of the block inquestion, a first stringer extending between and being fastened to the tops of the spacer blocks at the ends and the middle of one of said second pair of opposed bottom members,a second stringer extending between and being fastened to the tops of the spacerblocks at the ends and the middle of the other one of said second pair of opposed bottom members, and a third stringer extending between and being fastened to thetops of the spacer blocks at the ends and the middle of said intermediate bottommember, and a plurality of boards supported on and extending between the stringers to provide a platform adapted to support a load, the vertical separation between the stringers and the bottom members below the stringers being sufficient to permit entry of the tines of a fork-lift truck, wherein substantially all bottom members, spacer blocks, stringers and boards are constructed from thermoplastic-based material.

4. The pallet construction claimed in claim 3, in which the thermoplastic-based material consists of a matrix of thermoplastic material, together with at least one filler selected from the group consisting of: glass fibres, shredded thermosetting material, mica.

5. The pallet construction claimed in claim 3, in which each said spacer block is in the general shape of a right polygonal prism, having at least three vertical outside walls defining an internal chamber, and at least one vertical intermediate partition dividing said internal chamber into at least two sub-chambers.

6. The pallet construction claimed in claim 3, in which each said spacer block is in the general shape of a rectangular parallelepiped, having four vertical outside walls defining an internal chamber, and at least three vertical intermediate partitions dividing said internal chamber into at least six sub-chambers.

7. The pallet construction claimed in claim 3, in which each said spacer block is in the general shape of a rectangular parallelepiped with rounded vertical edges, having four vertical outside walls defining an internal chamber, and at least seven vertical intermediate partitions dividing said internal chamber into at least eighteen sub-chambers, all of which are open both top and bottom.

8. The pallet construction claimed in claim 5, in which each spacer block has, at the top and at the bottom, a non-planar surface exhibiting projecting portions and recessed portions, said portions interengaging with a similarly non-planar surface on at least one of the pallet components which the spacer block contacts.

9. The pallet construction claimed in claim 6, in which each spacer block has, at the top and at the bottom, a non-planar surface exhibiting projecting ribs and recessed channels, said ribs and channels interengaging with corresponding channels and ribs defined by a non-planar surface on at least one of the pallet components which the spacer block contacts.

10. The pallet construction claimed in claim 3, in which all components of the pallet construction are fastened together by a process which is selected from the groupconsisting of: induction welding, sonic welding, vibrational welding, hot plate welding, ferrous oxide induction welding, the application of an adhesive, and the utilization of an impregnated tape.

11. The pallet construction claimed in claim 5, in which all components of the pallet construction are fastened together by a process which is selected from the groupconsisting of: induction welding, sonic welding, vibrational welding, hot plate welding, ferrous oxide induction welding, the application of an adhesive, and the utilization of an impregnated tape.

12. The pallet construction claimed in claim 3, in which the bottom members, thestringers and the boards are made by heating and extruding said thermoplastic-based material to form an extrusion, and cutting the extrusion to desired lengths.

13. The pallet construction claimed in claim 12, in which said extrusion has a width several times as great as its depth, and is an integral structure which includes a top wall, a bottom wall spaced below said top wall, and two edge walls bridging between the top and bottom walls to define an interior volume, said volume being partitioned into a plurality of isolated cells by a plurality of upright partitions integral with the top and bottom walls of the extrusion.

14. The pallet construction claimed in claim 9, in which the bottom members, thestringers and the boards are made by heating and extruding said thermoplastic-based material to form an extrusion, and cutting the extrusion to desired lengths; said extrusion having a width several times as great as its depth, and being an integral structure which includes a top wall, a bottom wall spaced below said top wall, and two edge walls bridging between the top and bottom walls to define an interior volume, said volume being partitioned into a plurality of isolated cells by a plurality of upright partitions; said extrusion including said ribs and channels applied to the exterior of at least one of the walls of the extrusion.

15. The pallet construction claimed in claim 14, in which all components of the pallet construction are fastened together by a process which is selected from the group consisting of: induction welding, sonic welding, vibrational welding, hot plate welding, ferrous oxide induction welding, the application of an adhesive, and the utilization of an impregnated tape.