MXPA97010045A - Double cubie folding palette - Google Patents

Abstract

A single part of double-foil thermoformed plastic having parallel bands of plastic that form fillets that allow covering segments (in the direction of the deck of a ship), of the rigid pallet to fold after modeling and lock together in a support structure with a flat top cover spaced above a lower pallet cover with openings for the instruments or forks of the lift trucks. The lower cover has two segments joined by lateral beams to the upper cover, two central spar segments extend along the fold fillets from the lower cover half segments to lock in a certain place with the upper cover. The pallet is locked in a certain place with the top cover. The pallet is blocked in its configuration assembled by a bar that passes through joints formed below the central beams. The monocoque construction of the pallet provides an advantageous rigidity and a wide load bearing capacity, while being economical in its production. For an increased load capacity, the pallet can be formed with a reinforcing substrate, reinforced with a tubular steel insert. The pallet has an interlaminar step structure adjacent to each plastic fillet that transfers vertical loads and also resists the lateral deformation of the pale

Description

FOLDING PALLET OF DOUBLE COVER DESCRPTION OF THE INVENTION: The present invention refers to pallets or trays in general and particularly to pallets having double cover, this is top and bottom cover. The storage and transportation of a wide variety of items is greatly facilitated by the use of pallets or trays. The pallets allow the storage and movement of different items by a common management system using lift trucks with trident, in the first years of use of the pallets, most were built of wood due to low cost, easy availability and high compressive strength . Wooden pallets are still widely used in the industry. However, wooden pallets are subject to chipping, moisture absorption, and the steel fasteners that stop the vanes of aderaa ß oxidize if exposed to water. In general, wooden pallets have a limited life for their use. Plastic pallets are used advantageously where cleaning, repeated use or special needs arise. All general purpose pallets share several basic structural properties. They have a flat top cover to support boxes, crates or crates, and have two or more openings to accept the teeth of the forks. The openings for the teeth can be formed either between a top cover of the pallet and a lower cover of the pallet or the pallet can have a single cover, in the direction of the deck of a ship, with an arrangement of legs that support the cover on a support surface to allow the fork to enter under the cover. Many manufacturing processes have been adopted for the production of plastic pallets, injection molding, cellular foam, blow molding, and rotodeck, however the large size of the pallets frequently of 120 cm and even larger, makes the process thermowing Particularly suitable for the production of pallets. A successful path for a plastic pallet is presented in US Pat. 4, 428, 360 to Drßsden, which is a pallet produced in a double-leaf thermoforming process, in which the upper sheet merges with the lower sheet in the leg walls. similar to cups that protrude downwards. Another way to plastic pallets is presented in U.S. Patents 5, 197,396; 5,329,862; 5, 351, 629 and 5,413,052 to Breezer, which uses thermoformed two-ply top and bottom covers that are connected by posts-plastic feet molded separately. Such vanes can be adapted to high loads by tubular steel reinforcements between the plastic sheets of the upper cover, the lower cover, or both. In the thermoforming process a sheet of thermoplastic material is heated until it becomes soft and moldable but not fluid. The heated sheet is held against a mold which produces a vacuum between the mold and the plastic sheet pulling the sheet to the mold and causing them to be modeled on the surface of the mold, in the molding of both sheets both the upper sheet and the lower, they are heated and molded simultaneously in two separate molds, then the heated sheets are pressed together into the molds. The effect is to create an article that can stop included volumes and plastic regions of a desired thickness. The material handling of products such as pallets, which are highly engineered products, where the physical execution is weighed against the cost. Because the cost of the plastic resin that goes on the pallet is the important part of the total cost, there is a need to produce a pallet that has excellent performance and rigid capacity, with little resin weight. Providing a pallet with two covers, it contributes to a total rigidity of the pallet, however multiple parts in one pallet contribute to increase the cost due to separate molding operations, fasteners required and work for the assembly. In addition, the advantage of two covers for a joined rigidity decreases when the parts that connect the covers are subject to a lateral movement between them. What is needed is a double-deck plastic pallet that is assembled economically from a minimum of parts, and yet offers good structural performance. The double-cover blade of this invention is assembled from a single part of double-molded thermo-molded plastic, having parallel bands of plastic forming fillets that allow the rigid cover segments to be folded after being molded and fixed to a structure of support with a flat top cover spaced above a lower cover with opening for the fork teeth, two restriction segments extend along the fold fillets from the half segments of the bottom cover, to block in place with top cover. The pallet is blocked in its assembled configuration by a bar that passes through hinges formed below the central constrictor bar. The construction of a blade part offers advantageous rigidity and load bearing capacity, while being economical to produce, for an increased carrying capacity, the blade can be provided with reinforcing substrates, such as a metal frame. The pallet has a step or step structure adjacent to each plastic fillet, which transfers the vertical loads and resists lateral deformation. The central constricting segments are connected to the lower cover segments in fillets that are machined to define hinges through which the cylindrical bar extends. The central stringer segments can be coupled with the upper pallet cover, with protruding bayonets having barbs or tines that fit into receptacles on the upper deck, or alternatively the central long segments can be locked with cylindrical rods extending through portions of the roof and the central constricting segments. It is an object of the present invention to provide a pallet with two separate covers that can be assembled from a single thermo molded double sheet part. It is an object of the present invention to provide a high rigidity plastic pallet. It is a further object of the present invention to provide a pallet that is easily recycled. It is another object of the present invention that the pallet is comparable in dimensions to a wooden pallet. It is also an object of the invention to provide the pallet that is resistant to lateral loads. It is another object of the invention to provide a pallet that can be stacked.

It is another object of the invention to provide a pallet with narrow side beams to admit the penetration of the standard forks into a pallet of standard dimension. It is another object of the present invention to provide a pallet that can be shipped flat and assembled at the destination. Other objects, features and advantages of the invention are apparent from the detailed description with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS. FIGURE 1 is an isometric view of the thermoformed double-layer part in a non-assembled and narrow vane according to the invention. FIGURE 2 is a bottom isometric view of the part of Fig. 1, partially assembled. FIGURE 3 is a bottom isometric view of the assembled vane according to the invention. FIGURE 4 is a top plan view of the vane of Fig. 3, with optional metal reinforcements shown in a hidden line. FIGURE 5 is a side elevational view of the vane of FIG. 4. FIGURE 6 is a cross-sectional view of the vane of FIG. 5, taken along section line 6- LA FIGURE 7 is a plan view of the underside of a fragment of the top cover forming a bayonet receptacle taken along line 7-7, in FIG. 6. FIGURE 8 is an open top view of FIG. the portion of the pallet indicated as 8-8, in Fig. 6, and showing the interacoplant tooth structure in the folding stent of the pallet. FIGURE 9 is an isometric view illustrating the thinning of the thermoformed portion to show the hinges between the central constrictor and the lower cover segment of the vane of FIG. 4. FIGURE 10 is a fragmentary sectional view cross section of the connection between the top cover and the central constrictors in an alternative embodiment of this invention, having key connectors on the central constrictors. FIGURE 11 is a fragmentary cross-sectional view taken along the connection line between the lower cover segments in another embodiment of this invention having central pin constrictors. Referring more particularly to Figs. 1-11, wherein like figures refer to similar parts, a double-lidded pallet 20 is shown, in Fig. 3. The pallet is assembled by folding the connected segments of a double sheet, the thermoplastic thermoplastic part 21, and joining the segments with a cylindrical bar 23, as shown in Fig. 2. The pallet 20, has a load bearing part on the cover 22, which is on a cover 24, which rests on a supporting surface. The upper cover 22 has an upper surface 25, flat and uninterrupted. It is advantageous that there is a flat top surface 25, because it is easily cleaned and does not provide an opportunity for liquids or debris to collect. The loads in the pallet are usually transported by a lifter operated by motor or manually, these devices have two elevating horizontal metal entries that are inserted under the load to be transported and then lifted and locked in position to move the pallet and the load supported. To provide access to the teeth of the lifting apparatus, the upper cover 22, of the vane is separated on the lower cover 24, by constriction segments or spars 28, 30, 32, 34. The lower cover 24 rests on a surface of support left below. This can be the pavement or floor of the store or it can be a loaded palette that is below. The lower cover 24, generally has rectangular openings 36, to allow the downward extension of the wheels of the lifting tooth. The inlet openings 29, for the tooth, are defined between the cover 22, 24, on each side of the central beams 32, 34, on the front and back of the pallet. The side entrance openings can be provided on the side rails 28, 30, although this reduces the load capacity of the pallet. As shown in Fig. 1, the preassembled part 21, is a single thermoformed article of double-cut sheet. The part 21 is formed in a conventional thermoforming process in which the upper sheet of the material 76 is heated and formed in an upper mold and pressed against a lower sheet of material 78, which has been heated and formed in a lower mold. The two heated and molded sheets are pressed together in their molds, and where they make contact there is a melting of the plastic. The preferred material is polyethylene. The key to economical operation of a plastic pallet is to obtain the maximum load capacity or structural rigidity for a given amount of resin. An important factor in determining the rigidity of a structure, in a certain place is its moment of inertia around that plane. In general, the moment of inertia of a cross section is the sum of all the areas of the cross section, by the distance of that area of the line with respect to which the moment of inertia is determined. Thus, the mass disposed on the outer fiber of the pallet 20, for example, in the vicinity of the surface 25, of the upper cover 22, or on the underside of the lower cover 24, will contribute advantageously to the structural rigides. The total structure of the pallet 20 approaches a monocoque design, with the thermo-molded walls of the part 21, arranged predominantly along the outer perimeter of the pallet 20. The pallet 21 has a first constrictor or lateral stringer 28, and a second 30, extending from the upper cover 22, along a first thread 38, and a second upper thread 40, respectively, the threads 38, 40, connect the longitudinal members 28, 30, to the cover 22, not only as an unassembled part 21, but what is important when assembled on the pallet 20- The fillets may be approximately .25cm thick or more and extend in a straight line along the connections between the cover and the edges. side stringers. Therefore, the fillets 38, 40 define crease lines around which the beams 28, 30 can pivot when the pallet 20 is assembled. The lower cover 24 is composed of a first segment 42, and another 44, the first segment 42 is connected to the first stringer 28, along a first lower stringer 46. The second segment 44 is connected to the stringer 30 by a second lower stringer 48. The first central stringer 32 is connected to the first segment 42. , by a plurality of short plastic segments which in the already assembled pallet define articulations, curves 50. As shown in Fig. 9, the joints are created by first forming a plurality of shells as square block protruding 52, which extend on a flat segment 54, of the part 21. When this part 21 is removed from the thermoformed molds for trimming, a path accessory 56 traverses along the part, so that the upper portions of the part and the shells 52, are removed leaving a square opening 58, between the joints 50, each joint has a width of 2.5cm, and is displaced from a joint 50, on an opposite central beam, so that when the two central beams 32 , 34, are put together, the joints 50, are interlaced and the wheel 23, can be inserted through them, having a plurality of joints 50, the tearing effort at any point of the bar, is decreased, becoming a bar acceptable narrow As shown in Fig. 2, each center member 32, 34 has four connectors 59, with narrow bayonets 60, which protrude from the beam and extend into four adjustment bags 64. These as shown in Figs. l and ß, open downwards from the lower side 27, of the upper cover 22, the connectors 59, in the form of a protruding box, fit inside the bags 64, and this coupling serves to resist the axial dislocation of the stringers from the upper cover. The bags 64, are separated by sections of full thickness of the upper cover to limit the effect of the bags on the entire thickness of the upper cover, A notch 62, is cut on the 64th floor, of each bag 64, to receive two adjacent bayonets 60, as shown in Fig. 6. The tapered beards 66, are formed at the end of each bayonet 60, so that the bayonets 60, are retained in a fitting fit with the cover 24. To add rigidity to the bags 64, on each side of the notch 62, four narrow rib bags 68, 70, extend from the floor of the bag to the plastic sheet defining the top surface 25, of the cover. Two of the bags 68 extend parallel to the recess 62, at the outer limits of the bag and two of the rib bags 70, they do so perpendicular to the recess 62. The two sets of ribs 68, 70 have two objects . These ribs provide a load transfer from the top cap vertically down to the center beams and also resist the deformation of the plastic in the area near the notch, which would result in the bayonet tending to be pulled out or skipped. As shown in Fig. 1, the molded part 21 is taken directly from the double sheet thermomounting machine and cut out by removing the excess of the two sheets from which that part has been molded. This trimming will include removing the shells as block 52, to form the curved joints 50, and cutting the openings 36, and trimming around the bayonets 60, and the perimeter of the part 21. As shown in Fig. 2, the part generally flat 21, in which the cover 22, has a thickness of 5cm, the bottom cover has 2.5, the spars approximately 4cm, the central spars 5cm, and the lower cover approximately 2.5, folding around the fillets 38, 40, 46, 48, and the joints 50, to be assembled on a pallet 20, having a greater thickness from the upper surface 25, of the upper cover 22, to the lower surface of the lower cover 24, for example, in the order of 18 cm. Conventional pallets with dependent legs usually require a deep pull in the molds - Due to this pull, there is a limit in which the leg can be narrowed so that it serves, the blade 20, can be formed with narrow side beams preferably in the range from 1.25 to 5cm. Because pallets conventionally use conventional 2x4 lumber, which is typically 3.75 wide, pallet lifting wagons often have teeth or fingers spaced apart to approach a wooden spar that is expected to be less than 5cm thick. The pallet 20 of this invention can form a vertical support member without deep depressions that when folded can simulate the dimensions of a regular wooden pallet, facilitating the use of the conventional material handling infrastructure. Because it is desirable to distance the forks of a lifter carriage, as much as possible for a better balance of the lifted material, the conventional equipment admits a wider central spar, usually up to 15cm. Therefore the pallet 20, employs the two central beams to provide much of the resistance to the lateral loads of the pallet. It should be noted that, if more than two central beams are desired, one or more additional beams can be provided by connecting one or more additional beams to the central beams discussed herein, due to the strength and elasticity in the plastic there will be some tendency of the part 21, to spring to its molded shape. As the fillets and joints become thinner, the spring tension that has to be overcome to fold and assemble the pallet will be reduced, on the other hand fillet and thicker joints will give considerable strength and duration to the pallet, and so it is desirable, even if accessories and bending rings are required to assemble the pallet 20. The thickness of the fillets can vary depending on the thickness of the leaves, of which the part 21 is molded, but as an example, a part with a combined thickness of starting leaves of approximately 0.60cm, it can have a fillet thickness of approximately 0.37cm. The part 21 can be assembled on the pallet 20, in a computer controlled automatic assembly frame, employing actuators to fold the individual pallet segments in place. Such an apparatus can be combined with an automatic trimming station. Alternatively, the parts 21 can be sent to a remote location in a non-assembled flat condition and assembled in the final location. This capacity is particularly useful for shipments by sea where the prices of the cargo are based on volume. Although fillets and joints define fold lines in part 21, it should be noted that they are not primarily a designated bending region, but are key structural regions that contribute to the operation of the pallet 20, the fillets being the primary members that transfer stresses from one component to the other (from the upper cover 22 to the spars 28, 30 and to the lower cover 24), similarly to how the welded bed transfers stresses, from a vertical plate to a welded horizontal plate. Therefore, some mechanical aids when assembling part 21, on pallet 20, may be needed. There are some contributions to the ease of assembly by folding part 21, shortly after withdrawing from the thermowing machine, when the part is still warmer than room temperature, and therefore more malleable. To contribute to the operation of the monocoque type of the pallet 20, the structure is provided adjacent to each fillet or joint arrangement 50, to contribute to the vertical transmission of loads, and to the resistance to lateral loads. It is desirable that the pallet 20 transmit loads vertically to the support surface, rather than in any direction, which would tend to deform the pallet. In addition, it is a conventional practice to orient the pallets with lateral application of force to place them in engagement with the lifting fork. Therefore, the pallet must resist lateral loads without the stringers of the covers falling off. As shown in Fig. 8, the five-sided polygonal teeth 72 are formed on the lower side 27 of the upper cover 22, which engages between pentagonal teeth 74 projecting upwardly from the side beams 28,30.1a. upper 76 of the cover 22 merges with the lower sheet 78 of the top cover between the teeth 72 in the semicircular depressions 80. Two ears 82 protrude downwardly within each depression 80. Because of these variations in the standard thickness of the sheet , it is convenient to have areas of excess plastic part to address it. the ears 82 accommodate this excess plastic and at the same time provide a foundation for the coupling teeth 74. The teeth 74 also engage against the ring 84 surrounding the depression 80. The side faces 86 of the teeth 72 engage flat projections 88 which extend horizontally between the teeth 74 of the side beam. As shown in Figure 6, further support for the shoulders 88 is provided by two short rib bags 90 on the outward side of the stringer of each stringer which merge into a short bag 92 on the inner side of the stringer directly. under the ledge 88. Two longer rib pouches 94 shown in Figures 2 and 3, formed on the outside of the lateral stringer, extend on each side of the tooth 74. Each pair of long ribbed bags 94 is fused to a single more pouch long 96 on the inner side of the crossbar. Therefore the teeth of the upper and lower cover that are on opposite sides of the fillets 3840, in the molded part 21, interlaminate when assembled in a pallet 20 to resist loads that would twist the pallet and would tend to dislodge the top cover of the spars. The ends of the pallet 20 occasionally have to settle on stacking beams where there is a high concentration of forces and a high local stress of settling on the stack. The connection between the side rails 28, 30 and the lower cover 24 is also provided with structure to promote vertical transmission of loads and to resist lateral deflection. As shown in Figure 1, the square teeth 98 extend downward from the side beams 38, 30 and engage with the square teeth 100 on the lower cover segments 42, 44. The two larger bags 94 are positioned to extend the square teeth 98 and assist in transmitting loads from the polygonal teeth 74. The square teeth 98 are spaced apart through the stems 46, 48 in the molded part 21, but they engage with each other when the side beams are folded around the fillets in an assembled pallet 20. The same arrangement of the lower square teeth 10 and the square teeth of stringer 98 is employed where the central stringers 32, 334 are connected to the lower cover 24. The teeth ensure that the stringers act as vertical walls suitable at right angles to the upper and lower cover, as well as providing a compression section particularly at the interface with the cover The pallet 20 may have increasing stiffness over a conventional double cover of the type wherein the upper and lower covers are connected against vertical separation, but will have little resistance to lateral displacement, because the upper and lower covers of the pallet 20 are blocked together . On a double-deck plastic pallet that has separate leg posts and pin-to-bolt between the covers, when a load is applied, there is a movement between the top cover, the legs and the bottom cover. This movement is equivalent to taking two tables, placing one on top of the other and applying a central load downwards. As a board is bent, it is free to slip and move relative to the other board, thus not increasing rigidity. On the other hand, the pallet 20 more easily takes the upper board and sticks it to the lower board, which will greatly improve the rigidity, because the total moment of inertia of the section has increased. As shown in Figure 1, a plurality of narrow oblong rib bags 102 are formed in the lower thermoplastic sheet 78 on the lower side 27 of the cover 24. The rib bags 102 extend upwardly from the underside 27 of the upper cover and fuse with the upper sheet 78 of the cover. The bags 102 are approximately eight times longer than wide, and are approximately 3.75 to 5 cm long. A series of pockets 102 are formed along a common axis to define a rib. The pleat covers 20 preferably employ a high stiffness snow pattern arranged to accommodate the anticipated load templates, as presented in U.S. Patent 5, 566, 624. The lower cover 24 is also provided with a plurality of bags of stiffening rib 102.

Where higher loads are anticipated, the pallet 20 can be reinforced with tubular steel in reinforcing substrates 104, 106 as shown in Figures 4 and 5. a top cover substrate 104 extending through the top cover 24 can to be used alone or in conjunction with a lower cover substrate 106. The alternative mode connections between the center beams and the top cover are shown in Figures 10 and 11. In the pallet 108 shown in Figure 10, a channel 110 is formed in the upper deck 112 with parallel side walls. Each center beam 114 has a protruding bayonet 116 with a concave recess 118 formed therein during the process of thermoforming the double sheet. The center stringers 114 are connected to the upper cover 112 by one or more plasters 120 which extend between adjacent bayonecks 116 within the channel 110. The channel 110 extends less than the length of the pallet 108, and the bar 120 it is inserted to pierce the end walls 122 of the channels so that the bar is blocked against an upward or downward movement. Because there is not enough space in the channel for the bayonets to pull past the inserted bar 120, the bayonets and thus the center beams are fixed in place. In such embodiment another bar would extend through the hinges to the lower cover as in the pallet 20. Another embodiment of the pallet 124, shown in Figure 11, replaces the solid bayonets with projecting shells or hulls 126 extending from the stringers. central 128 to the channel 130 formed in the upper cover 132. The alternating shells 126 extend first from a central spar, then from another, to alternately align with a bar 134 that pierces the end walls of the canal as well as all the shells 126 a lower bar 136 also extends through joints 138 from center beams 128. It should be noted that the bars connecting the central beams to the pallet covers can be formed of steel or other metal, as well as fiberglass or polyethylene . In addition, different rib templates and cover configurations can be used to fulfill particular applications of the pallet. In addition, although tubular steel reinforcement substrates have been introduced, substrates from other cross-sectional areas or materials such as wood, fiberglass, plastic, and fiber and resin composites may be used for reinforcement purposes. It is understood that the invention is not limited to the particular construction and arrangement of parts illustrated herein, but encompasses those forms modified within the scope of the present invention.

Claims (23)

1. R E I V I N D I C A C I O N E S l. A pallet comprises: a thermoformed double-leaf upper cover, having a generally flat top surface, a first lower-leaf thermoformed bottom cover segment; a second double sheet thermoformed lower cover segment, wherein the first lower cover segment and the second cover segment together comprise a lower cover which is disposed below and substantially parallel to the upper cover; a first double-layered thermoformed lateral stringer extending along a first lower integral plastic fold region from the first lower cover segment, and along a first upper plastic region from the upper deck, at wherein the first lower plastic fold region is substantially parallel to the first upper plastic folded region; a second double-layer thermoformed lateral stringer qeu extends along the second lower integral plastic fold region from the second lower cover segment, and along a second upper integral plastic fold region from the cover upper, wherein the second lower plastic fold region is substantially parallel to the second upper plastic region; a first double-leaf thermoformed central stringer extending along a first central crease region from the first segment of the lower cover, the first central stringer having portions engaging with the top cover, so that the first central stringer it is basically parallel to the first lateral crossbar and the second lateral crossbar; and a second double-leaf thermoformed central stringer extending along a second central crease region from the second lower shell segment, the second center stringer has portions engaging with the top cover, so that the second central stringer it is basically parallel to the first lateral stringer and to the second lateral stringer, and wherein the second central stringer extends in tight relation to the first central stringer, the upper cover, the first segment of the lower cover, the second segment of the cover bottom, the first side spar, the second side spar, the first center spar, and the second center spar are formed as a single double-leaf thermomolded part and are assembled by folding on a pallet
2. 2. - The pallet according to claim 1, wherein each central spar has at least one projecting bayonet extending in portions of the notches defining the upper deck.
3. 3. The pallet according to claim 1, wherein the first region of liegue has portions defining a plurality of joints and the second region has portions defining a plurality of joints, which are interlaminated with those of the first region, and wherein a bar is inserted through the interlaminated joints to prevent separation of the first center stringer from the second center stringer.
4. 4. - The pallet according to claim 1, wherein each central stringer has a plurality of connecting members that penetrate from the stringers to portions of the upper cover, which defines coupling bags, the connecting members with the bags to restrict the axial displacement of the central beams with respect to the upper cover.
5. 5. The pallet according to claim 4, wherein a bayonet extends from each of the central beams such that a bayonet from two adjacent central beams extends in an adjacent relationship, between the recesses in the bag. Union on the upper deck.
6. 6. - The pallet according to claim 2, wherein beards or tapered spines are formed at the end of each bayonet, so that the bayonets will be retained in a snap fit within the recess in the coupling bag on the top cover.
7. 7. The pallet according to claim 1, wherein the upper cover has at least one channel that opens downward, and wherein each central spar has at least one protruding bayonet with portions defining a concave recess, so that the adjacent bayonets extend into the channel of the upper deck so that the concave recesses face each other, and where a bar pierces a wall in the upper deck and passes through the concave recesses in the central beams to prevent the escape of the central stringers of the canal.
8. 8. - The pallet according to claim 1, wherein the top cover has at least one channel that opens down, and wherein each center member has portions that penetrate the channel, and where a bar perforates a plurality of walls in the upper deck and passes through the central spar perforating portions to prevent the escape of the central stringers of the channel.
9. 9. The pallet according to claim 1, wherein interlocking teeth are formed in the stringers through the fold regions from the teeth formed in the top cover, so that the teeth of the top cover engage with the teeth of stringer to carry vertical loads from the upper deck to the stringers, and resist lateral loads.
10. 10. The pallet according to claim 1, wherein the interlocking teeth are formed on the stringers through the fold regions from the teeth formed in the lower cover segments, so that the teeth of the segment of the lower cover fit with the teeth of the stringer to carry vertical loads from the stringers to the segments of the lower deck, and to resist lateral loads.
11. 11. The pallet according to claim 1, wherein horizontal flange of the side beams is when more than about the width of a wooden 2 x 4.
12. 12. The pallet according to claim 1, wherein the center beams are connected to the segments of the lower cover by a plurality of foldable plastic strips, and the foldable strips extend from the first lower cover segment and are positioned adjacently, the strips extend from the second lower cover segment. , and the foldable strips wrap a connecting member extending intermediate, the connecting member prevents the first central stringer from separating from the second central stringer.
13. 13. The pallet according to claim 12, wherein the connecting member is a cylindrical bar.
14. 14. The pallet according to claim 13, wherein the bar is made of a material selected from the group consisting of steel, fiberglass, plastic, composite fiber and resin.
15. 15. The pallet according to claim 1, wherein the upper cover has a plurality of bags formed therein, which are approximately eight times longer than wide, and extend from a lower side of the upper cover to the surface. On top of the upper deck, the bags are arranged in a pattern that follows the anticipated loading patterns of the upper deck.
16. 16. A pallet that employs a monocoque structure comprising: a thermoformed double-leaf top cover having a generally flat upper surface defining the structure of the external fiber; a first thermoformed double-leaf gauge extending between the upper deck and the lower deck; a double-leaf thermoformed side rail, which extends between the upper deck and the lower deck, and the first side rail and the second side rail are fixed to both the upper deck and the upper deck to transfer loads from the upper deck to the upper deck. bottom cover and to resist lateral loads; at least one double-leaf thermoformed central stringer which is positioned laterally between the first lateral stringer and the second lateral stringer and which extends between the upper cover and the lower cover, where each of the double-leaf thermoformed cover, the cover lower, the side and center beams have a plurality of elongated ribs there formed which extend between a first sheet of thermoplastic material and a second sheet of thermoplastic material; and an interlocking structure formed in the upper track engaging the projecting structure on the central beam to resist movement of the central beam with respect to the top cover.
17. 17. The pallet according to claim 16 wherein the lower cover comprises a first lower cover segment that extends parallel to the second lower cover segment.
18. 18. The pallet according to claim 17, wherein the first side spar and the second side spar extend from the upper deck along foldable plastic sheets and the lower cover segments extend from the side spars to along foldable plastic fillets and at least one central spar extends from one of the segments of the lower cover.
19. 19. The pallet according to claim 1, wherein two central spars extend from two parallel lower cover segments comprising the lower cover, and each central spar has a projecting connecting member extending into recessed portions of the lower deck. the upper cover, the connecting members engage with the recess portions to restrict the axial displacement of the central spars with respect to the upper cover.
20. 20. The pallet according to claim 19 wherein two central stringers extend from the lower cover segments along a plurality of joints and the joints of each interlaminar center stringer, and a bar is inserted through the stringers. interlaminated joints to prevent the separation of the two central beams.
21. 21. The pallet according to claim 19, wherein a bayonet extends from each of the central beams so that a bayonet from two adjacent central beams extends in a relationship adjacent to each other within the recesses in the coupling bag on the top cover.
22. 22. - A thermoformed part of double sheet to be assembled in a pallet comprising: a thermoformed double-leaf top cover having a generally flat upper surface; a first double-foil thermoformed lower cover segment extending from a first side of the upper cover along a foldable plastic fillet; a second tempered sheet double bottom cover segment extending from the top cover along a foldable plastic fillet along a second side of the top cover; a first thermoformed double-layered side panel extending along a first infeed fillet from the first lower segment and along a first fillet superior from the upper deck, wherein the first lower fillet is substantially parallel to the first fillet. first top steak; a second double-sided thermoformed lateral stringer extending along a second lower fillet from the second lower cover segment and along a second upper fillet from the upper deck, wherein the second lower fillet is substantially parallel to the fillet higher; a first double-leaf thermoformed central stringer extending along a first central fillet from the first lower cover segment, the first central stringer having portions protruding outward from the first central fillet; a second double-leaf thermoformed central panel extending along a second central fillet from the second lower panel segment, the second central bar having portions protruding outwardly from the second central filet; and portions of the top cover defining a depression located to receive portions of the center beams where the center beams are folded to engage the upper deck, and the upper deck, the first segment of the lower deck, the second segment of the deck. bottom cover, the first side spar, the second side spar, the first center spar, and the second center spar are formed as a single thermo-patterned double-leaf part and extend substantially parallel to each other, and are arranged to be folded forming a palette.
23. 23. A pallet comprising: a thermoformed double-leaf top cover having a generally flat top surface; a thermoformed double sheet lower cover spaced parallel to and below the top cover; a first double-leaf thermoformed lateral stringer extending between the upper deck and the lower deck; a second double-leaf thermoformed lateral stringer extending between the upper deck and the lower deck, wherein the first side spar and the second side spars are fixed to both the upper and lower deck, to transfer loads from the upper deck , to the lower cover and to resist lateral loads; two double-leaf thermoformed central stringers that are laterally placed between the first lateral stringer of the second lateral stringer and extend between the upper and lower cover, and an interblocking structure formed in the upper cover that engages with a projecting structure on the stringer central to oppose the displacement of the central spar with respect to the upper cover, and means for resisting the deflection of the lateral spars with respect to the upper cover and the lower cover formed on the side spars. SUMMARY A single part of double-foil thermoformed plastic having parallel bands of plastic forming fillets that allow covering segments (in the direction of the deck of a ship), of the rigid pallet to fold after being modeled and blocked together in a support structure with a flat top cover spaced above a lower pallet cover with openings for the instruments or forks of the lift trucks. The lower deck has two segments joined by side rails to the upper deck, two central spar segments extend along the fold fillets from the lower deck half segments to block in some place with the top cover. The pallet is blocked in its configuration assembled by a bar that passes through joints formed below the central beams. The monocoque construction of the pallet provides an advantageous rigidity and a wide load bearing capacity, while being economical in its production. For an increased load capacity, the pallet can be formed with a reinforcing substrate, reinforced with a tubular steel insert. The pallet has an interlaminar step structure adjacent to each plastic fillet that transfers vertical loads and also resists lateral deformation of the pallet.