Patent Publication Number: US-7908979-B2

Title: Pallet having load bearing capabilities on which articles may be placed for storage and/or transportation

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a pallet. 
     This invention has particular, but not exclusive, application to a pallet that is used as a moveable platform on which goods are placed for storage and/or transportation, including handling using a forklift truck. However, it will be appreciated that this invention may also be used in the construction of a base for various types of packaging to be used for storage and/or transportation of goods, including containers and creates. 
     Pallets typically include a platform and a plurality of dependent supports that are capable of supporting the platform above a foundation or a structure, such as a rack, upon which the pallet rests. Further both the arrangement of the supports and the space separating the platform and the foundation upon which it rests are typically sufficient to allow a forklift tine to be located there between. 
     It will be appreciated that the cost of a consumer item is dependent upon many factors including the cost of packaging, transportation and storage of the item. 
     Pallets, being a load bearing structure, have traditionally been manufactured from heavy and expensive materials, such as timber and steel. Whereas once there was an abundance of timber and pallets and other forms of packaging made from timber were viewed as throwaway items, timber has in recent years become a scarce resource. As a consequence the cost of timber, and therefore pallets, has increased in recent years. 
     Further, in an effort to prevent the transfer of unwanted pests and diseases from one country to another, some countries will only permit the importation of goods made of materials that are known to be good carriers of pests and diseases, such as timber, if they have been chemically treated. Accordingly, in order to comply with the customs requirements of many countries, pallets made from timber must be fumigated, which adds to the costs associated with the transportation and storage of consumer items. 
     Typically freight charges are dependent upon the combined weight of the article and any associated packaging. Accordingly, it is desirous that any packaging, including pallets, used for the transportation of goods be made from light weight materials, such as various plastics materials. 
     In highly competitive markets, such as those relating to the sale of electronic goods and “white” goods, where margins are small, savings relating to the cost of transportation and storage of items are most desirous. 
     In an effort to overcome the problems associated with pallets made of timber, various vacuum formed pallets having a core made from expanded polystyrene encapsulated by an external skin made from a thermoplastics material have been developed and are currently being used. However, the inventors are not aware of either a two way entry and/or a four way entry, rackable, vacuum formed, pallet. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a pallet that ameliorates at least some of the deficiencies of the prior art and/or a two way entry, vacuum formed, pallet that is rackable, and/or a four way entry, vacuum formed, pallet that is rackable, and/or a stronger vacuum formed pallet, and/or a vacuum formed pallet that is more economical to produce, and/or a vacuum formed pallet that is more durable. 
     With the foregoing in view, this invention in one aspect relates to a rackable pallet having load bearing capabilities on which one or more articles may be placed for storage and/or transportation, including: 
     a body having a platform that includes an upper side face upon which the article or articles may rest and a plurality of supports that depend from an underside face of said platform, said supports being adapted to provide support for said platform and to space said platform above a foundation or a structure on which the pallet rests, said body being constructed from predominantly one or more light weight materials having no or little inherent load bearing capacity; 
     an external skin that is bonded to and envelopes the underside face of said platform and said supports and at least some of the upper side face of said platform, and 
     a plurality of bridges that extend between adjacent supports, said bridges being spaced from the underside of said platform and adapted to provide support for the pallet when at least some of said bridges rest upon frame members of a rack, and whereby in use a forklift having a plurality of tines may be used to move the pallet and wherein each tine may be locatable between adjacent supports and/or between the underside of said platform and one or more bridges. 
     In another aspect, this invention relates to a pallet having load bearing capabilities on which one or more articles may be placed for storage and/or transportation, including: 
     a body having a platform that includes an upper side face upon which the article or articles may rest and a plurality of supports that depend from an underside face of said platform, said supports being adapted to provide support for said platform and to space said platform above a foundation or a structure on which the pallet rests, said body being constructed from predominantly one or more light weight materials having no or little inherent load bearing capacity; 
     an external skin that is bonded to and envelopes the underside face of said platform and said supports and at least some of the upper side face of said platform, and 
     a plurality of wear resistant members that are affixed to an underside of at least some of said supports and which are adapted in use to bear against a foundation upon which the pallet rests. 
     Preferably the pallet is a rackable pallet and wherein the wear resistant members are bridges that extend between adjacent supports, said bridges being spaced from the underside of said platform and are adapted to provide support for the pallet when at least some of said bridges rest upon frame members of a rack. 
     In still yet another aspect, this invention relates to a pallet having load bearing capabilities on which one or more articles may be placed for storage and/or transportation, including: 
     a body having a platform that includes an upper side face upon which the article or articles may rest and a plurality of supports that depend from an underside face of said platform, said supports being adapted to provide support for said platform and to space said platform above a foundation or a structure on which the pallet rests, said body being constructed from predominantly one or more light weight materials having no or little inherent load bearing capacity; 
     an external skin that is bonded to and envelopes the underside face of said platform and said supports and at least some of the upper side face of said platform, and 
     a plurality of surface projections that depend from a lower face of at least some of said supports, said projections being adapted to engage a foundation, such as a conveyor. 
     Preferably the engagement of the projections with the foundation is an interlocking engagement. 
     Preferably, the pallet includes one or more foundation engaging members and wherein the surface projections are associated with said foundation engaging member or said foundation engaging members, and wherein the foundation engaging member or each foundation engaging member is attached to one or more supports. Further, it is preferred that the pallet is a rackable pallet and wherein the foundation engaging members are bridges that extend between adjacent supports, said bridges being spaced from the underside of said platform and are adapted to provide support for the pallet when at least some of said bridges rest upon frame members of a rack. 
     The platform may be any suitable shape. However, in the preferred form of the invention the platform has a substantially square shape when viewed in plan. 
     The upper side face of the platform may include at least one groove or channel formed therein that is adapted to receive a lower edge portion of a structural member or a side wall used in the construction of a package that is adapted to surround one or more articles to be stored and/or transported on said pallet. 
     The supports are preferably arranged in rows such that a forklift tine is locatable between adjacent rows of supports. Further, it is preferred that the supports are arranged in longitudinally and transverse extending rows thus forming either a two way entry pallet or a four way entry pallet. 
     The body may be constructed from a variety of light weight materials including cardboard, particle board, cellulosic fibre cement timber, various plastics materials and other porous or air permeable substances. However in the preferred embodiment the body is constructed from expanded polystyrene (EPS) and wherein the platform and the supports are formed integrally using a suitable moulding process. 
     It is believed that the density of the expanded polystyrene used in the construction of the body will influence the strength of the pallet. In particular it is believed that the greater the density of the expanded polystyrene the greater the strength of the pallet. 
     Further, it is believed that the extent to which the expanded beads used in the construction of the body fuse together also influences the strength of the pallet. 
     It is also believed that the strength of the pallet is influenced by the extent to which the external skin bonds with the body. In particular it is believed that the greater the surface area of the external skin that is bonded to the body the greater the strength of the pallet. 
     During the vacuum forming process, the heated skin is urged into contact with the body. In order that the heated skin may fuse with the body, preferably as much air or other gas trapped between the skin and the body is removed and wherein the extent to which the skin fuses with the body is influenced by the ability of the vacuum forming process to remove these gases. 
     However, increasing the density of the expanded polystyrene used in the construction of the body will also inhibit the flow of air through the body during the vacuum forming process. To counter this, a plurality of cavities and/or openings are formed in the body. These preferably extend between the upper side of the platform and the underside of the platform and/or between the upper side of the platform and the underside of the supports. 
     In the preferred embodiment, the expanded polystyrene has a density in the order of 28 kg/m3, and wherein the degree of fusion preferably is equal to or greater than 70%. 
     It is also preferred that there are provided a plurality of openings or cavities formed in the platform having a diameter of approximately 3 mm, said openings being located between the supports. In the preferred embodiment the openings extend between the underside face and a point located just below the upper side face. 
     The material from which the skin is made may include one or more of the following materials: acrylonitrile butadiene styrene; polyester; styrene; polycarbonate; PET; APET; PETG; lead free PVC; copolymer polyester/polycarbonate; and HDPE. 
     Preferably the external skin includes a bottom sheet that covers the supports and the underside face of the platform and a top sheet that covers the upper side face of the platform. 
     In the preferred embodiment, the external skin is manufactured from high impact polystyrene, (HIPS), or a composite HIPS structure and wherein the top sheet is approximately 0.6 mm thick and the bottom sheet is 1.2 mm thick. 
     It is also believed that the ability of the supports to resist compressive loads is greatly enhanced if each of the side walls includes a plurality of generally longitudinally extending ribs. 
     The bridges may be manufactured from any suitable material. For example, the bridges may be constructed from wood, metal and/or various plastics materials, including lead free PVC. However, in the preferred embodiment, the bridges are manufactured from HIPS using an extrusion forming process. 
     Further, the bridges may be configured so that they each span two or more supports of a row and are preferably affixed to the end walls of each of said supports so that they interconnect same. For example, the bridges may be affixed to abutting end walls using a suitable adhesive. 
     In still yet another aspect, this invention relates to a pallet formed using a vacuum forming process, said pallet having load bearing capabilities and on which one or more articles may be placed for storage and/or transportation, said pallet including: 
     a body having a platform that includes an upper side face upon which the article or articles may rest and a plurality of supports that depend from an underside face of said platform, said supports being adapted to provide support for said platform and to space said platform above a foundation or a structure on which the pallet rests, said body being constructed from expanded polystyrene, and 
     an external skin that is bonded to and envelopes the underside face of said platform and said supports and at least some of the upper side face of said platform, characterized in that there are formed a plurality of cavities and/or openings in said body. These cavities and/or openings preferably extend between the upper side of the platform and the underside of the platform and/or between the upper side of the platform and the underside of the supports. 
     Preferably the pallet is a rackable pallet and wherein the pallet also includes a plurality of bridges that extend between adjacent supports, said bridges being spaced from the underside of the platform and adapted to provide support for the pallet when at least some of said bridges rest upon frame members of a rack, and whereby in use a forklift having a plurality of tines may be used to move the pallet and wherein each tine may be locatable between adjacent supports and/or between the underside of said platform and one or more of said bridges. 
     In still yet another aspect, this invention relates to a pallet formed using a vacuum forming process, said pallet having load bearing capabilities and on which one or more articles may be placed for storage and/or transportation, said pallet including: 
     a body having a platform that includes an upper side face upon which the article or articles may rest and a plurality of supports that depend from an underside face of said platform, said supports being adapted to provide support for said platform and to space said platform above a foundation or a structure on which the pallet rests, said body being constructed from expanded polystyrene, and 
     an external skin that is bonded to and envelopes the underside face of said platform and said supports and at least some of the upper side face of said platform, characterised in that each of said supports includes a plurality of side walls located between the underside of said platform and an end wall of said support and wherein all of said side walls of at least some of said supports include a plurality of ribs that extend between the underside of said platform and said end wall. 
     Preferably the pallet is a rackable pallet and wherein the pallet also includes a plurality of bridges that extend between adjacent supports, said bridges being spaced from the underside of the platform and adapted to provide support for the pallet when at least some of said bridges rest upon frame members of a rack, and whereby in use a forklift having a plurality of tines may be used to move the pallet and wherein each tine may be locatable between adjacent supports and/or between the underside of said platform and one or more of said bridges. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the invention may be more easily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein:— 
         FIG. 1  is a top view of a four way entry, vacuum formed, rackable pallet that is constructed in accordance with the present invention and which includes a skin covered pallet body and an assembly of bridges; 
         FIG. 2  is a bottom view of the pallet illustrated in  FIG. 1 ; 
         FIG. 3  is a front view of the pallet illustrated in  FIG. 1 ; 
         FIG. 4  is a side view of the pallet illustrated in  FIG. 1 ; 
         FIG. 5  is an exploded view showing the skin covered pallet body and the assembly of bridges apart and in line for assembly; 
         FIG. 6  is an exploded view showing the skin covered pallet body and the assembly of bridges, said assembly of bridges being shown apart and in line for assembly; 
         FIG. 7  is a top view of a foam body or blank that is constructed in accordance with the present invention and which is used in the manufacture of the pallet illustrated in  FIG. 1 ; 
         FIG. 8  is a bottom view of the foam blank illustrated in  FIG. 7 ; 
         FIG. 9  is a top view of the foam blank illustrated in  FIG. 7 ; 
         FIG. 10  is a side view of the foam blank illustrated in  FIG. 7 ; 
         FIG. 11  is an end view of the foam blank illustrated in  FIG. 7 ; 
         FIG. 12  is a bottom view of the foam blank illustrated in  FIG. 7 ; 
         FIG. 13  is a cross-sectional view on AA of the foam blank illustrated in  FIG. 7 ; 
         FIG. 14  is a cross-sectional view on BB of the foam blank illustrated in  FIG. 7 ; 
         FIG. 15  is a detailed view from F of the foam blank illustrated in  FIG. 7 ; 
         FIG. 16  is a cross-sectional view of an end portion of another pallet constructed in accordance with the present invention. 
     
    
    
       FIGS. 1 to 6  show a pallet  10  that is constructed in accordance with the present invention. 
     The pallet  10  includes a body or blank  11 , see  FIGS. 7 to 15 , comprising a multitude of high impact polystyrene beads that are fused together. Preferably the body  11  is formed using a two part mould and wherein the density of the beads is approximately 28 Kg/m3 and the level of fusion is at least 70%. 
     The body  11  includes a platform  12 , having a substantially square shaped, generally flat, upper side face  13  and an opposing underside face  14 , and a plurality of supports  15  that depend from said underside face. 
     The supports  15  are arranged in rows that extend both transversely and longitudinally across the surface of the underside face  14 . Further, the supports  15  include four corner supports  15   a  that depend from a respective corner of the platform  12  and which have a substantially square shaped transverse cross-section. The corner supports  15   a  each include two pairs of opposing, downwardly tapering, side walls  16  and an end wall  17  in which there is formed an  A L@ shaped channel  18 . 
     The outer facing side walls  16   a  and  16   b  of each corner support  15   a  include two grooves  19  and  20  respectively that are formed therein and which extend between the underside face  14  of the platform  12  and the end wall  17 . 
     The inner facing side walls  16   c  and  16   d  of each corner support  15   a  include three grooves  21 ,  22  and  23  respectively that are formed therein and which extend between the underside face  14  of the platform  12  and the end wall  17 . 
     The supports  15  include four middle supports  15   b  and wherein each middle support  15   b  is located midway between two corner supports  15   a.    
     Each middle support  15   b  includes two pairs of opposing, downwardly tapering, side walls  24  and an end wall  25  in which there is formed a  A T@ shaped channel  26 . The outer facing side wall  24   a  and its opposing side wall  24   b  each include two grooves  27  and  28  respectively that are formed therein and which extend between the underside face  14  of the platform  12  and the end wall  25 . 
     The other two side walls  24   c  and  24   d  each include three grooves  29 ,  30  and  31  respectively that are formed therein and which extend between the underside face  14  of the platform  12  and the end wall  25 . 
     The grooves  28 ,  29  and  30  are connected to opposing grooves  21 ,  22  and  23  by three grooves  32  formed in the underside face  14  of the platform  12 . 
     The supports  15  also include a central support  15   c  that depends from the centre of the platform  12 . The support  15   c  has a substantially square shaped transverse cross-section and includes two pairs of opposing, downwardly tapering, side walls  33  and an end wall  34  in which there is formed a  A cross@ shaped channel  35 . 
     The side walls  33  each include two grooves  36  and  37  formed therein which extend between the underside face  14  of the platform  12  and the end wall  34 . The grooves  36  and  37  are connected to an opposing pair of grooves  27  and  28  by two grooves  38  formed in the underside face  14  of the platform  12 . 
     The grooves  38  divide the underside face  14  into essentially four quadrants  39  and wherein the underside face  14  of each quadrant  39  includes a series of five grooves  40  formed therein. 
     The platform  12  also includes a matrix of cavities or bores  45  that surround each of the supports  15 . The bores are individually formed during the moulding process by a respective pin that is mounted on one part of the mould and wherein when the two parts of the mould are brought together, the pins extend into the mould cavity. 
     Each bore  45  includes an open end  46  that opens to the underside face  14  and an opposing closed end  47  that lies just below the surface of the upper side face  13 . Further, the bores  45  are of substantially constant cross-section and, in the case of a pallet that is 1100 mm square, have a diameter of approximately 3 mm. 
     The platform  12  also includes two opposing pairs of side walls  51 . Each side wall  51  is substantially rectangular in shape and includes a chamfered top edge portion  52 . 
     The supports  15  and the underside face  14  of the body  11  are preferably covered by a generally rectangularly shaped bottom sheet  60  made of lead free PVC. The sheet  60  is preferably of substantially uniform thickness, approximately 1.2 mm, and has a peripheral edge portion  61 . Further, the sheet  60  preferably has a substantially smooth outer face  62  and an opposing, substantially smooth, inner face  63 . 
     During construction of the pallet  10 , the pre-heated sheet  60  is brought in to contact with the end walls of the supports  15  and the peripheral edge portion  61  is clamped against abutting side walls  51  of the platform  12  using a tool or die, not shown. Then gases that are trapped between the sheet  60  and the underside face  14  are subsequently drawn through the body  11  thereby creating a partial vacuum between the underside face  14  and the sheet  60 . 
     The forces created by the partial vacuum both urge and, where necessary, stretch the sheet such that it bears against and becomes bonded to the side walls of the supports  15  and the underside face  14  of the body  11 . 
     It is believed that the bores  45 , because they are located adjacent each of the supports  15 , help ensure that the bottom sheet  60  bonds to the side walls of the supports  15  and those portions of the underside face  14  that are adjacent the supports  15 . 
     The clamping of the sheet  60  against the side walls  51  causes the portions of the sheet that are in contact with the side walls to bond with same. 
     Preferably the manufacturing process involves the use of a tool that prevents the peripheral edge portion  61  of the sheet  60  from coming into contact with the side walls. Instead the peripheral edge portion  61  shall overlie yet diverge away from the side walls. 
     Finally those portions of the bottom sheet  60  that are covering the openings of the bores  45  are each pierced using a respective retractable pin. 
     The upper side face  13  of the body  11  is preferably covered by a generally rectangularly shaped top sheet  70  made of lead free PVC. The sheet  70  is preferably of substantially uniform thickness, approximately 0.6 mm, and has a peripheral edge portion  71 . Further, the sheet  70  preferably has a substantially smooth outer face  72  and an opposing, substantially smooth, inner face  73 . 
     During construction of the pallet  10 , the pre-heated sheet  70  is supported above the body  11  by a tool that is adapted to hold the peripheral edge  74  of said sheet. The body  11  is then advanced such that the upper side face  13  makes contact with the inner face  73  of the sheet  70  and whereupon any gases trapped between said inner face and said upper side face are drawn through the body  11 , aided by the inclusion of the bores  45 . The resulting partial vacuum forces the sheet  70  against the upper side face  13  ensuring that as much of said sheet as possible will bond with said face. 
     The peripheral edge  74 , when released by the tool holding same, is then folded over and pressed against the exposed portions of the side walls  51  of the body  11 . Then, the peripheral edge portion  61  of the sheet  60  is folded over and heat bonded to the peripheral edge  74 . 
     The pallet  10  also includes a plurality of bridges  80  that extend between adjacent supports  15 , said bridges being spaced from the underside face of the platform by said support. 
     The bridges  80  are each formed from an extruded plastics material, such as lead free PVC, and comprise a hollow core that extends the length of the member and one or interconnecting webs. 
     The individual bridges  80  are adapted to be received in the various channels  18 ,  26  and  35  formed in the end walls  17 ,  25  and  34  respectively of the supports  15  and are preferably retained therein by friction and/or a suitable adhesive. 
     The peripheral bridges  80   a  are each provided with opposing mitred end portions  81 . Abutting end portions  81  of adjacent bridges  80   a  are interconnected by a stake having opposing end portions that are frictionally retained within a respective bore. 
     The three internal bridges  82 ,  83  and  84  are preferably interconnected to one another where they meet at  85  and where the abut respective peripheral bridges  80   a  at  86  using a suitable connector. 
       FIG. 16  shows a cross-sectional view of an end portion of a pallet  110  that is very similar to the pallet  10 . The pallet  110  includes a body  111  comprising a multitude of high impact polystyrene beads that are fused together. 
     The body  111  includes a platform  112 , having a substantially square shaped, generally flat, upper side face  113  and an opposing underside face  114 , and a plurality of supports  115  that depend from said underside face. The supports  115  are arranged in rows that extend both longitudinally and transversely across the surface of the underside face  114 . 
     The platform  112  also includes two opposing pairs of side walls  151 . Each side wall  151  is substantially rectangular in shape and includes a groove  151   a  that has been formed either during the moulding process used to produce the body  111  or subsequently pressed into said side wall  151 . 
     The supports  115  and the underside face  114  are covered by a generally rectangularly shaped sheet  160  made of lead free PVC and wherein the sheet  160  includes four peripheral edge portions  161 . 
     During construction of the pallet  110 , the pre-heated sheet  160  is brought into contact with the supports  115  and the peripheral edge portion  161  is clamped against abutting side walls  151  of the platform  112  using a tool, not shown. Then gases that are trapped between the sheet  160  and the underside face  114  are subsequently drawn through the body  111  thereby creating a partial vacuum between the underside face  114  and the sheet  160 . 
     The forces created by the partial vacuum both urge and, where necessary, stretch the sheet such that it bears against and becomes bonded to the side walls of the supports  115  and the underside face  114  of the body  111 . 
     The partial vacuum that is created also urges the sheet  160  to both conform to and bond with the side walls  151  of the platform  112 , including the grooves  151   a , but wherein a tool not shown prevents the peripheral edge portions  161  from making contact with the platform. Instead, the peripheral edge portions  161  each form a flap  200  that extends outwardly from the side walls  151  above the grooves  151   a  at an inclined angle, as shown in  FIG. 16 . 
     The upper side face  113  of the body  111  is preferably covered by a generally rectangularly shaped top sheet  170  also made from a lead free PVC and wherein the sheet includes four peripheral edge portions  171 , each having a peripheral edge  174 . 
     During construction of the pallet  110 , the pre-heated sheet  170  is supported above the body  111  by a tool that is adapted to hold the peripheral edges  174  of said sheets. The body  111  is then advanced such that the upper side face  113  makes contact with the sheet  170  and whereupon any gases trapped between the sheet  170  and the upper side face  113  are drawn through the body  111 . The resulting partial vacuum forces the sheet  170  against the upper side face  113  ensuring that as much of said sheet as possible bonds with said face. 
     Further, following trimming of the peripheral edges  174  of the sheet  170 , the partial vacuum also forces the edge portions  171  to both conform to and bond with the side walls  151  such that they cover an upper side face  201  and a lower side face  202  of an adjacent flap  200 , and wherein the tab  200  has a tendency to be drawn into an adjacent groove  151   a , as shown in dotted outline. 
     It will be appreciated that the bridges  80  provide support for the pallet  10  when at least some of said bridges rest upon frame members of a rack. 
     Further, it will be appreciated that the bridges  80  do not prevent the location of forklift tines between the underside face of the platform  12  and opposing bridges, and between opposing rows of supports  15 . 
     It will also be appreciated that the frame comprising a plurality of interconnected bridges  80  aids in preventing the splaying apart of the supports when heavy loads are placed on the pallet  10 . 
     It is also believed that the addition of grooves formed in the outer side faces of the supports  15  will strengthen the pallet  10 , and in particular the supports  15 . 
     It has also been observed that the size of the load that may be supported by the pallets  10  and  110  is influenced by the size of the bearing area, namely the size of the surface area of the end walls  17 ,  25  and  34 . The greater the bearing area the greater the load that the pallets can support. 
     In order to increase the bearing area and hence the load capacity of the pallets  10  and  110 , it is proposed that the distance separating adjacent supports be minimized. However it is understood that the minimum distance separating adjacent supports must be sufficient to enable two adjacent tines of a forklift or similar lifting apparatus to each pass simultaneously between adjacent rows of supports  15  and  115 . 
     Bearing the above in mind, it is proposed that the distance separating adjacent supports for most pallets be in the order of 80 mm. 
     It will of course be realised that while the foregoing description has been given by way of example of this invention, all other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as herein defined in the appended claims.