text: the pallet shown in fig1 generally by reference numeral 10 , is prepared from synthetic resinous thermoplastic sheet material of between about 30 to about 120 mils average sheet thickness , and most preferably about 30 to 80 mils . as such , the pallet weight is between about 21 / 4 to 9 lbs , and most preferably , between about 21 / 4 to 6 lbs . generally , for a load of about 1000 lbs , a sheet of about 30 - 45 mils is usually suitable . such pallets are designed for at least double stacking . thus , the pallet for this specific load size must withstand a column load force of 2000 lbs . for pickup , moving , and setting down other than pure column loading forces , of course , must be accepted by the pallet , and overwrap combination disclosed below . the specific and enabling design features of pallet 10 include a raised generally rectangular platform or flexible sheet 12 , which typically will represent the original plane of the sheet from which the pallet is prepared . essentially the entire surface area of platform 12 is columnized . hence , densely packed individually small columns or column means 14 , each an imperforate cone shape and tapered downwardly , are employed to define the desired raised platform feature . the columns 14 collectively comprise a rigid base in the vertical direction which supports platform 10 . the columns are of critical design and spacing . most ideally , the column spatial arrangement is set to define a center faced , hexagonal pattern as shown in fig4 . this pattern or other appropriate patterns which characterize the distinguishing pallet structure of the invention require that no straight lines ( imaginary ) may be drawn between adjacent rows of columns 14 without intersecting columns in both rows . to illustrate this , imaginary straight lines l1 and l2 are shown in the fig4 view . since the column means are staggered and closely bunched , it is thus apparent that lines l1 and l2 , or any straight lines , may be drawn between adjacent column rows ( on the plane of platform 12 ), without intersecting columns in both rows . the generic pattern of which center faced , hexagonal is the most desirable species , thus requires columns set out in staggered rows , and with sufficiently close spacing so that no drawable straight lines , in the mode supra exist between such rows , as mentioned . other known patterns or column spatial arrangements that exemplify this design feature may be beneficially utilized in constructing pallets 10 . the shape of the columns requires a taper from the plane of the raised platform , but is not limited to the cone shape illustrated . for example , modified columns of 3 - 7 point star shape may be utilized . similarly , with respect to fig5 the following column forms of octagonal 14a , fluted 14b , and hexagonal 14c , are considered advantageously incorporated in the pallet design of this invention . other than a non - preferred square shape or other similar non - preferred shapes that present 90 ° corners , the column configuration may thus assume a wide number of generally quite comparable forms . the critical aspects of the column 14 structure require a height ( alternatively viewed as depth ) dimension &# 34 ; h &# 34 ; in fig5 in the range between about 3 / 4 &# 34 ; to 2 &# 34 ;, and most preferably between the even narrower range of about 1 1 / 4 &# 34 ; to 1 3 / 4 &# 34 ;. in conjunction , the column density and average column cross - sectional area is critically specified . cross - sectional area , with the numbers used herein , means the cross - section of the column at the midpoint in its height or plane 1 / 2 &# 34 ; h ( as shown by dotted lines in fig7 and as calculated using the column o . d . dimension ). average cross - sectional area of the columns is about 2 . 0 square inches or less , and most preferably about 1 . 7 square inches or less . in addition , column density , excluding the area of sidewall 12 , is between about 10 - 40 columns per square foot of platform 12 , and about 15 - 25 columns per square foot of platform is most preferred . the non - column or non - ground supported spans or flexible sheet portions , given reference numeral 16 , are defined in pairs centered on the imaginary x and y axis ( arbitrarily designated ) of the platform . such extend across the length and width of the platform thus defining opening spaces 18 underneath platform 12 . as is apparent by the location of the non - supported spans , the same are positioned for balanced lifting of the loaded pallet . as illustrated by the side view of fig3 the entry points may be easily identified by the fork lift operator . two pairs of spans 16 will be used , as shown , to construct a pallet 10 capable of 4 - way entry ( see fig1 ) and one pair of spans would be necessary for a 2 - way pallet , as contemplated in fig1 . further structure in the platform is the provision of platform stiffening means , preferably hollow elongated ribs or rib means 20 , laterally spaced and aligned with the x - axis , and similar ribs 22 aligned with the y - axis . these ribs may be downwardly formed as shown in the cross - sectional view of fig7 or upwardly formed from the plane of the sheet as shown by the dotted line 22 in the same figure . most preferably , the elongated ribs are centered on the axis of the aligned column means in each row as illustrated , and 90 ° out of phase . the rib design and position may desirably assume known modified designs of which a grid pattern of numerous rib increments of varied phase angles would be considered a suitable design and rib placement species . the sidewall construction , element 24 in the drawing , is also critical in conjunction with the raised platform design of the pallet . in this respect , the sidewall is stepped at 26 and 28 ( either locally or continuously ) as shown best in fig3 and 7 . importantly , also the top edge 30 of the sidewall is rolled or turned to a partial or complete curl as shown . the curl is desirably outwardly as shown in the preferred form of the invention . reinforcing ribs ( such as like that described with regard to platform 12 below ) may be substituted for steps 26 , 28 , but would be less preferred . sidewall height &# 34 ; b &# 34 ; is between 2 and 10 inches , in order to protect the vulnerable base of the palletized load . the lower base 32 of the sidewall is also considered a critical design parameter where the pallet is required to size itself to the product load , as is typically the case for unitized boxed loads . the design is also desirably featured in pallets for industrial bag loads although being less critical in this application . a radius r of between about 1 / 2 &# 34 ; to 1 1 / 4 &# 34 ; is specified for the self - sizeable pallet design . the case for an undersized load is illustrated in fig8 wherein the amount of undersizing is represented by a spacing &# 34 ; u &# 34 ; of 11 / 2 inches between the sidewall and load ( considered an extreme discrepancy ). using the radius described , the pallet sidewall bends along the radius as shown in dotted lines , making intimate contact with the base of the product load . the case for an oversized product load is represented in fig9 . here the load bears against the base of the sidewall , forcing it outwardly as shown . however , because the pallet is slightly oversized , by the described radius of the lower base thereof , the sidewall is readily retrieved into intimate contact with the sides of the load , as shown by the dotted lines , illustrating the sidewall in the retrieved position , as shown in fig1 . in conjunction with the flexible and this self - sizing pallet design created by the structure , supra , the sidewall is further modified , as shown in fig1 by removing the four corners of the sidewall , preferably in the form of &# 34 ; v &# 34 ;- shaped or equivalently tapered cutouts 34 , as shown by dotted line illustration . thus , the sidewall is converted to essentially independently moveable members , that are individually bendable inwardly to achieve the compact , intimate contact desired between the pallet sidewall and load . the taper of the sidewall is also desirably controlled to a value of between about 10 ° to 15 ° with the vertical ( see fig7 ). particularly for the case of the fig1 pallet design , and less critically for the sizeable pallet design of fig8 - 10 , the taper , where provided , renders the pallet quite suitable to automatic product loading equipment , even that equipment as has been designed for intended use with conventional non - sided wooden or plastic pallet structures . pallets designed according to fig1 and having the x and y dimensions of 40 &# 34 ; and 46 &# 34 ;, respectively , sidewall height of 4 &# 34 ;, and column height of 11 / 2 &# 34 ;, and prepared from 80 mil sheet , may be nested compactly for shipment of new pallets , or for return of used pallets . in the specific pallet design referred to , supra , pallets in nested form , each require a stacking height of only about 3 / 8 &# 34 ;. nesting points identified in such stacked pallets are the rolled edge 30 , in conjunction with the ribs 20 , 22 . while reverse tapered , more conventional nesting detail may be added to this pallet design , jamming is not observed , hence , suggesting that such added features may frequently be avoided while retaining satisfactory nestability . the use of pallets 10 in conjunction with a untized , individualized product load 36 , stacked in a traditional interlocking pattern , is illustrated in fig1 ( the term &# 34 ; individualized &# 34 ; being used to describe a load of numerous articles as opposed to a single or few articles ). minimal or no observed sagging of the non - column supported spans is observed with respect to corrugated boxes , as an example . for the illustrated industrial size bags , normally meaning bags of about 25 or more pounds in weight , however , some sagging of the unsupported spans is observed . for example , using the specific pallet mentioned , supra , with a column height of 11 / 2 &# 34 ;, span width of 7 &# 34 ;, column density about 14 , average cross - section 1 . 7 square inches , and prepared from 80 mil sheet , and loaded with 2500 lbs , of 50 lb size industrial bags , the sagging observed , while more exaggerated , remains within quite acceptable limits , for this more difficult case . what has been surprisingly observed in the study of pallet 10 , is the reverse deformation of span 16 after the initial lifting activity , as illustrated by dotted line 38 in fig1 . while peculiar to the case of bag loads , it is with this type product that the upward set 38 taken in the span areas is of most utility to the design principles of the invention . in a stacked pallet arrangement , the pallets 10 may be alternately supported on conventional warehouse pallets . the pallets are preferably moved and stored in the warehouse using this mode of handling , and since the warehouse pallets are continually reused , little added expense is required . for shipments in trucks and boxcars , the warehouse pallets reamin behind , and the pallets of this invention are loaded and stacked , using conventional methods . a paper board , or plastic sheet may be used at the top of the pallet loads to avoid the succeeding pallet stacked atop the lower pallets from engaging the product directly . to enable forklift handling , the load is unitized by a film or net overwrap or by banding , herein generically termed &# 34 ; wrap means &# 34 ;, which unitizes the product load , and binds the product load to the pallet . assuming a film stretch overwrap , the most preferred form , the film 40 is wound circumferentially generally several times about the product load , extending downwardly about the sidewall of the pallet . rolled edge 30 together with the stepped geometry of the sidewall , effectively attaches the tightly wound stretch wrap to the pallet . shrink wrap and netting ( preferably inferring plastic netting material ) may be applied in the same mode . the shrink wrap is customarily subjected to a post shrinkage step , to tighten it against the load and pallet . the thusly prepared pallet load may be handled in the conventional manner by a forklift mechanism . the openings 18 at the underside of the pallet are positioned so that the forks apply a generally balanced lifting force . the lightweight pallets of the invention , particularly , have the capability for easy retrieval of the lifting fork after the pallet load is set down , because of the raised platform design that minimizes frictional interferences between the fork and underside of the pallet . also the sidewall substantially avoids warpage and remains strongly attached to the film overwrap . for example , the 80 mil pallet described performs admirably with 2500 lbs of loaded industrial bags . the pallets may , in fact , be stacked two high , as conventional for boxcar shipments , and their functionality unimpaired . since this pallet weighs only 6 pounds , the pallet load weight ratio is an extremely advantageous 416 plus , and where stacked , an effective 832 plus . moreover , the compact pallet design , which is undersized compared to conventional wooden pallets , is ideally suited for convenient handling in the normally tight spacing load arrangements used to maximize the useable space of the boxcar . also since the pallet referred to is an experimental design prepared by thermoforming under vacuum pressure using a wooden mold , very poor distribution of material in the more deeply drawn column area is achieved . using more suitable aluminum faced molds , and maximized columnization of platform 12 , comparable utility is expected for this application using 50 to 70 mil sheet . economics are such that typically pallets 10 may be used at considerably less than their optimum loading ratios . in generalized terms , therefore , 30 to 45 mil sheet thickness , per thousand pound , is usually suitable for bag loads , and a lesser 30 - 40 mils for box loads per thousand pounds . hence , pallet 10 is characterized as suitable in purpose to perform admirably at superior pallet / load weight ratios of 300 : 1 , it being understood that the pallet oftentimes may be subjected to even much greater loads . preferred plastics for constructing pallets according to this invention comprise thermoformable sheets of plastic most preferably of ethylene and propylene homopolymer or copolymers . more generally , any extrudable and thermoformable plastics , including those with binders and particularly inexpensive off grade , and recycled plastic scrap materials can be considered as a suitable substitute for preparing pallets 10 , either alone , or if not entirely satisfactory alone , in admixture with other plastics . fiber reinforcements such as glass fibers may also be incorporated in the sheet from which the pallet is prepared , for even added and quite inexpensively attained strength properties .