Plastic handling pallet and manufacturing method

FIELD OF THE INVENTION The present invention relates to a pallet operated by a fork having a pallet, the upper surface of which is used to accommodate goods. The pallet itself is located on a support surface and is used to lift, lower and forward the goods and materials placed on it. The invention also relates to a process for making a pallet. The invention is particularly advantageous for the treatment of goods in industries with high hygiene requirements; such industries as the food, pharmaceutical and cosmetics industries, as well as industries based on clean technologies.

There are many types of pallets that can be operated with forks. Such pallets are, for example, subject to the approved French standard NF H 50-001. The pallets described herein have a top plate which rests on three guide members. This arrangement provides sufficient space between the guide members so that a fork-lift fork can be introduced into the spaces between the guide members.

Pallets of this type are generally used for transporting and storing all kinds of materials and goods, and pallets are traditionally made of wood by making a plurality of parallel planks of pallets. There may be gaps between the planks or they may fit directly together. The planks are usually nailed to three transverse members having the same or substantially identical thickness of the planks forming the pallet, and these transverse members extend along the overlapping ends of the planks and in the center, about halfway between the two outermost transverse members.

The guide members are located beneath the transverse members and may be formed by solid beams or, in order to reduce the weight and cost of the pallet, several separate blocks may be used instead of the guide members formed by such beams.

Below the blocks, lower planks can be installed that are parallel to the pallet planks, and each guide member will have the appropriate planes. The blocks are connected to one another along their opposite surfaces to their transverse elements.

The use of lower planks increases the stability of the guide members formed from separate blocks.

Pallets of the type described above meet the requirements for transporting and loading a wide variety of materials and goods. However, if hygiene considerations are to be taken into account, wood, and in particular the way in which the planks, transverse members and blocks are joined, is not acceptable for handling (loading and transporting) unpackaged food. The woody surface, as well as the gaps that are necessarily present between adjacent planks, which are nailed to each other, make it impossible for them to be cleaned perfectly hygienically as germs, cracks and pores settle and in fact, the same phenomenon occurs on the wood surface itself.

It has been suggested that pallets of the type described above be made of a non-wood material whose surface can be perfectly cleaned. However, the problem of microbial colonization and proliferation in the gaps between the planks of this material is still present, and this problem cannot be solved simply by changing the structural material used.

For example, U.S. Pat. No. 2,371,106 discloses a pallet having a pallet made of a plurality of planks held together by transverse members; the latter to the planks^-are secured by means of additional fastening devices. The elements of this pallet, i.e. the planks and the transverse members, may be made of plastic. However, the fact that the pallet elements are held together by additional fastening devices automatically results in the appearance of cracks and • gaps in the joints of the elements.

To eliminate the aforementioned phenomenon of bacterial colonization in slits, it has been proposed to use pallet pallets that can be treated with a fork and used for food processing, with the same geometry as described above, except that the pallet does not contain multiple parallel planks, are made by encapsulating a metal or wooden reinforcement with polyethylene, and this reinforcing structure is completely embedded in the polyethylene.

In practice, however, it has been shown that during the repeated use of this type of pallet, during which the pallet was washed between each use cycle, cracks occurred after a certain number of use cycles due to incompatibility of the stiffness or heat expansion properties of the molten plastic and stiffening material. very important places, which, of course, again favored the establishment and multiplication of microbes, but were virtually impossible to clean, since the very small size of these cracks made their effective cleaning virtually impossible.

British Patent No. 420,222 relates to a pallet operated pallet having a pallet located at a distance from a supporting surface, which allows the entry of a fork, such as a fork lift fork, into the space below the pallet. This pallet has a pallet made of a plastic material, such as polyethylene, and a spacer structure for positioning it at a distance from a supporting surface, and the latter is made of a plastic material, such as polyethylene. However, the spacer structure is made up of hollow elements and additional support means are required to ensure that the spacer structure is not detached from the pallet.

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It is an object of the present invention to overcome the drawbacks of the presently known and discussed similar solutions and to provide a pallet which is reasonably priced, i.e. less expensive than injection-molded pallets, while fully meeting the hygiene requirements of the food industry.

It is a further object of the present invention to provide a process for the manufacture of these types of pallets which is easily adaptable to pallets of various sizes, which allows to adapt to the needs of the users. This adaptation is very difficult to achieve with the aforementioned known plastic injection pallets and can only be implemented at a very high cost.

The object of the present invention is to provide a pallet which can be handled (raised, lowered and conveyed) by means of a forklift, which is made of a plastic, such as polyethylene or polypropylene, , and also made of plastic, providing a space between the supporting surface and the pallet, for example, it has a spacer structure made of polyethylene or polypropylene, characterized in that the pallet and the spacer structure providing the clearance between the pallet and its supporting surface are made of solid plastic in the event of their breaking through a blunt object.

In a preferred embodiment, the spacer structure is secured to the pallet by a polyfusion process to prevent the retention of gaps or / and pores between them.

Another embodiment of the pallet is characterized in that one of the outer surfaces has a protruding circumferential region forming a watertight rim around the attachment zone.

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According to a further feature of the invention, the surfaces to be joined are fused together to ensure continuity between the organic chains of their materials.

It may also be expedient in the embodiment in which the spacer structure comprises a plurality of blocks which are directly attached to the lower surface of the pallet.

In a further embodiment of the pallet according to the invention, the spacer structure has a plurality of guide members, each of which is directly attached to the free end of the blocks.

It may also be desirable to have the guide rails arranged in a continuous strap arrangement.

Another embodiment of the pallet according to the invention is characterized in that the blocks

- thin flat sheet; obsession

- a solid shape, such as a solid cube; obsession

- sheet with a concave side; obsession

- a curved plate having protruding branches; or a combination of two or more of the above.

According to a further feature of the invention, the pallet comprises a palletizing device, for example, on the upper surface of the pallet having means adapted to receive complementary devices formed on the underside of a spacer structure of another pallet spaced apart to form this pallet. In this case, it is expedient that the stacking structure on the upper surface of the pallet is formed by a plurality of upwardly projecting portions of the sheet having gaps between them which are acceptably formed by the lower portion of the spacer structure or stacking structure of the next pallet; and if the stacking structure on the upper surface of the pallet is formed by a plurality of recesses into which the lower regions of the end portions of the elements forming the stacking structure on the lower portion of the next pallet are inserted.

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In another embodiment, the upper surface of the pallet board has an embossed structure formed by a heat transfer pressing process or / and the surface comprises microperforations.

It may also be advantageous for the stacking device to be formed as an embossing structure formed on the lower surface of the lower portion of the spacer structure and this lower embossing structure for engagement with the embossing structure formed on the upper surface of the next pallet pallet. the next pallet is adapted to prevent horizontal displacements in both directions.

The pallet and the guide members are joined by a method of melting the material where the elements forming the pallet fit together; melting is accomplished by thermal communication technology using heat reflection, linear vibration welding, or microwave or ultrasonic welding. Polyfusion bonding eliminates the risk of gaps in the joints or cracks in the pallet when used.

The pallets of the present invention may be subjected to an additional treatment operation after polishing between the pallet and the spacer structure to support the spacer from the supporting surface to remove the burr from the pad.

The present invention also relates to a process for making the pallets described above, characterized by:

- forming pallet elements from plastic sheets and / or rods by cutting or shaping;

- the surface areas of these elements which are intended to be bonded to similarly heated surface areas of other such elements;

- attaching at least one first heated surface region to at least one second heated region;

- applying a predetermined pressure to the two elements, the heated surface areas of which have previously been joined to one another;

- cooling the heated surface ranges, including maintaining the applied pressure.

In a preferred embodiment of the process, the batch formed as a result of pressure applied to the heated surface regions is removed.

According to another preferred aspect of the invention, the surface areas are heated to a temperature of 100 ° C to 300 ° C.

It may also be desirable to provide the upper surfaces of the pallet boards with a pre-polished lattice shape prior to polishing or / and to form the pallet boards by microperforations. In general, it is preferred that the surface regions of the pallet elements (components) are melted using heated mirror technology, linear vibration welding technology, or ultrasonic or microwave welding technology.

The invention will now be described in more detail with reference to the accompanying drawings, which show preferred embodiments of a pallet. 1 is a perspective view of a first embodiment of a pallet according to the invention;

Figure 2 is a bottom view of the pallet of Figure 1;

Figure 3 is a perspective view of another embodiment of a pallet according to the invention;

Figure 4 is a bottom view of another embodiment of a pallet according to the invention;

Figure 5 is a side view of another embodiment of a pallet according to the invention; this solution makes it possible to form pallets from pallets;

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Figure 6 shows a further embodiment of a pallet according to the invention suitable for forming a pallet;

7-9. Figures 4 to 5 are bottom views of some of the pallet details of the invention;

Figures 10 and 11 show, in sectional views, two operation steps by which the pallet sections can be joined together;

Fig. 12 is a side view of an embodiment of a pallet according to the invention suitable for forming a pallet;

Figure 13 is a top plan view of an embodiment of a pallet pallet of the present invention;

Figure 14 is a larger detail, in more detail, of a top view of an embodiment of a pallet of the invention;

Fig. 15 illustrates an operation step of manufacturing a pallet according to the invention using a heating mirror melting technique.

Fig. 1 is a perspective view of a first embodiment of a pallet according to the invention for use with a fork. All embodiments of the pallet according to the invention have a pallet 30 spaced from the respective supporting surface, such as floor or ground. This spacing is provided by the spacer device, generally designated by reference numeral 31. The spacer structure 31 has elements spaced apart to provide sufficient clearance to accommodate the forks of a forklift truck, such as a forklift truck or the like.

One problem solved by the pallet according to the invention is that when the fork of the forklift reaches at full speed into the gaps of the known spacer structure of the loaded pallet, such a large impact occurs on the fork. · Between the pallet and the pallet that the hollow plastic blocks are cracked, pieces may break, consequently, cracks and cavities suitable for colonization and proliferation of bacteria and microbes occur, which are extremely difficult to clean and hygienically comply with, even if particular care is taken in this regard.

To overcome this problem, the present invention employs a molded solid plastic such that, even in the case of a fracture, cracks and pores that are unacceptable hygienically in industries such as the food industry in which the pallet is intended to be used.

In the embodiment of Fig. 1, the pallet 30 has an upper surface 32 or an upper side and the materials to be treated (lifted, lowered, conveyed, loaded) are placed there. Such materials may be, for example, cheeses or pieces of meat which are in bulk, but of a more or less regular geometric shape. The lower side or surface of the pallet 30 is designated 37 in Figures 1 and 2. The elements of the aforementioned spacer structure 31 are fixed to this lower surface 37. In the present embodiment, the spacer structure 31 is made up of a plurality of blocks 33-35 having a foot surface which is closed against their surface fitting to the lower surface of the pallet, since the material itself is solid. These base surfaces 36 serve to support the pallet on a supporting surface such as ground or floor.

Figure 2 is a bottom view of the pallet of Figure 1. From the drawing it can be clearly seen that the blocks are in three parallel rows of lines and each row has three or three blocks.

The pallet is preferably formed of a single rectangular planar plate. Any solid flat sheet may be used for this purpose which does not contain, or may contain, cracks or pores which are impossible or inconvenient to clean.

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The spacer elements 31 are joined to the lower surface 37 of the pallet 30 by a polyfusion process that results in the restoration of the molecular chains of the material of the two contacting components, resulting in the at least peripheral zones of the joining region between the two components. Thanks to this connection, there is no chance of any cracks, gaps, pores or the like appearing in which bacteria can colonize and microbes multiply.

Figure 3 is a perspective view and an upside-down view of another embodiment of a pallet according to the invention; otherwise, consisting in part of the same structural members as the pallet of Figures 1 and 2. Identical structural elements are designated by the reference numerals already used in Figures 1 and 2. In this embodiment, the blocks 3335 are interconnected by guides 40, 41 and 42 extending along their free ends. These guide members 40-42 extend in one of the main directions of the pallet, i.e. one side, and thus parallel to one another. The guide members 40-42 are formed by rectangular pieces of plate made of solid plastic and secured by the polishing process described above.

Figure 4 is a bottom view of a third embodiment of a pallet for treating a fork in accordance with the present invention. In the embodiment of Fig. 4, the same structural parts as in Fig. 1 were used, but in addition, the strap 45 was incorporated. In a preferred embodiment, the strap 45 is formed of a flat plastic sheet which is pierced by four rectangular openings; these openings are designated by reference numerals 46-49. By means of the belt 45 thus formed, the blocks 33-35 are connected to one another by means of the upper surface of the flat plate belt 45 (not shown). In Figure 4, we raised it with dashed lines and hatches ···· ········································································································································································································ ·· · ···· ··· out the range occupied by each block which fits over the upper surface of the 45 straps. In Figure 4. FIGS. 4A and 4B also show the lower surface of the spacer elements of the pallet assembly of this embodiment.

Figure 5 illustrates a plurality of pallets 50 and 51 according to the invention from which a stack may be formed. The pallet 50 formed as shown in Figure 4 rests on a supporting surface 52 such as the floor of a department store. 5 is a side view of the pallet. The pallet 53 of the pallet 50 comprises projections 54 and 55 designated to penetrate the openings 66 and 67 of the next pallet 51 contained in the strap 68 of the second, upper pallet 51. This strap 68 is thus configured to fit the sheet portions 54 and 55 which are located on the upper surface 32 of the pallet 30. Thus, in this embodiment, the upper surface 32 of the pallet 30 of the pallet 30 of the present invention comprises four upwardly projecting portions having a height substantially equal to the thickness of the spacer strap, thereby allowing multiple pallet pallets to be formed. stored pallets can be shipped together as a single unit to the locations required by the merchandise store.

The sheet portions 54 and 55 may be bonded to the upper surface of a flat pallet 30 by gluing, welding or the aforementioned polishing process (such as that shown in Figure 1). In another embodiment, the disc portions are not formed by discrete and welded or welded or polyfusion-bonded portions of sheet material, but by mechanical removal of excess material from the upper surface of the pallet 30 of each pallet; in this case, of course, a thicker sheet material is required.

Figure 6 shows another embodiment of a pallet according to the invention for palletization. In general, the palletizing means of the pallet according to the invention are formed by means of the spacer.

<img file="HUT73293A_D0002.tif" />

elements are located on the lower surface of these elements, or the surfaces are formed for stacking, which is a spacer structure for providing a clearance between a supporting surface such as a floor and a pallet. The shape of these stacking means is selected to fit with additional means formed on the upper surface of the pallet pallet. In this case, this first pallet forms the supporting surface of the second pallet of the pallet.

The stacking device of Figure 6 is particularly advantageous for stacking from the pallet of Figure 1. On the supporting surface, such as the floor 70, in the case of Fig. 6, two successive (superposed) pallets 71 and 72 are shown, each of which is formed by a pallet 73 and a spacer 74 formed by a plurality of blocks. The upper surface of the pallet 73 of the pallet 71 comprises a plurality of recesses 75, 76, 77 in which the end portions 78-80 of the stacking structure elements of the next (upper) 72 are located at the bottom. In this case, the stacking structure on the underside of the next spacer 81 is directly formed by the end portions 78-80 of the spacer 81, i.e. the supporting surfaces.

Obviously, to improve the stacking operation, the recesses of the exemplary embodiment of Figure 6 and the side surfaces of the lower portions of the spacer members may be skewed to provide mutual centering, which is required when placing a second pallet from the top of an existing stack. , and the price of a pallet that acts as a supporting structure for the next pallet.

The same arrangement with an inclined surface can be envisaged for the construction of the stacking structure described above in Figure 5.

7-9. Figures 3 to 5 show three practical and possible embodiments of solid blocks forming the spacer structure of the pallet according to the invention.

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Generally, the pallets of the present invention may be made of solid sheets. Solid plates may be elongated but may also be formed of rectangular parallelepipedons of rectangular cross-section or solid blocks formed by cubes. Other shapes have also been studied which are particularly well suited to the fact that the forks of goods handling machines, such as forklifts, pose a danger to the pallet. In view of this aspect, solid blocks are preferably formed with profiles that cause relative deflection of movement of said fork as it is introduced into the spaces between the spacer structure.

A possible variant of the cross-sections favoring this aspect is shown in Figure 7, which includes curved surfaces. The profile of the block 90 shown here is located within a rectangular enclosure section indicated by dashed lines. This block 90 is formed by two adjacent C-shaped plates 91 and 92. The size of the gap 93 between the sheets 91 and 92 is selected such that the block has a plurality of points through which the block is capable of receiving shocks and shocks caused by a machine for handling goods such as a forklift fork.

Figure 8 shows another embodiment of the block, denoted by reference numeral 94, having an X profile within the parallelepipedon, which has four outer faces 95-98 arcs.

A third embodiment of a block for use with the cargo pallet according to the invention is shown in Figure 9.

The block 99 shown in the latter figure, as in the embodiments of Figures 7 and 8, is located within a rectangular section (can be drawn on such a piece) and has a cross-sectional shape with an upwardly V-shaped profile section 100 substantially perpendicular to the protruding branch portions 101 and 102 of the profile. As a result of this design, three cavities are formed which are referred to as 103, 104 and 105

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with numbers. These cavities, each accessible from the outside of the pallet, have a plurality of points which enable the block to absorb shocks and impacts caused by a fork-lift truck or other fork-lift truck.

We have found that FIGS. The blocks having the profiles shown in Figures 1 to 4 have the most favorable mechanical properties, in particular when they are connected to the lower surface of the pallet of the pallet according to the invention or to the upper surface of the guide members or to the strap of the spacer.

The embodiment of Figures 10 and 11 is particularly suitable for carrying out a polishing process using a mechanical friction process.

Figure 10 is a sectional view taken through a first portion 110, such as a block, and a second portion 111, such as a pallet, of a pallet of the invention. The lateral edge 113 of the end region 112 of the first portion 110 is formed so as to completely surround the interface between the two portions. In the first part 110, it is clearly visible that the recesses 114 and the projections 115 are formed together. The two parts are brought to one another by pressure movement in the direction of the arrow 116 and are moved in place by a special machine which is not directly related to the present invention and therefore is not illustrated or described. The pallet portions shown in FIGS. 1A to 5b can be vibrated relative to one another in the directions corresponding to arrow 117. By appropriately selecting the vibration acceleration pressure, the contact areas of the first portion 110 and the second portion 111 are perfectly interlocked, as can be seen in FIG. The circumferential scar 118 is formed by melting the lateral edge 113 (protruding portion) of the first portion 110 and ensuring that the joint between the two portions 110, 111 is watertight. Another advantage of this solution is that it allows the elimination of any cracks or gaps due to the fusion process between the two parts.

Figure 12 is a view showing a stacking structure used in another embodiment of the pallet according to the invention. In this embodiment, a support surface, such as a floor, is designated by reference numeral 120, and on that support surface are placed two pallet trucks manipulated by forklifts, designated by reference numerals 121 and 122, which occupy the position prior to stacking, i.e. to the lower one, which is already resting on the supporting surface. The pallets are shown in Figures 2 and 3. 2 to 3, wherein the members of the spacer structure are joined to one another by guides or straps along their lower surface. The upper surface of each pallet pallet includes recesses which are produced by a hot stamping process, which, however, is not directly related to the present invention and which serves to increase the friction coefficient of said surface relative to any other material. This solution in itself is advantageous, not only for stacking, but also for transporting goods that, simply because of the combined effect of gravity and inertia, may fall to the ground or floor when the forklift or other conveyor loader begins to accelerate. However, joining with such an embossing structure can also advantageously be used for stacking. To this end, the lower surface 123 of the next pallet 122 is also provided with embossed shapes (not shown), which is an embossing shape complementary structure and serves to engage with an embossed structure on the upper surface 124 of the pallet 121 the solution keeps the pallets secured to each other even when subjected to lateral acceleration, whereas the relationship between embossed structures is capable of holding up to 99 V · 99 V ·

and prevent horizontal movement between adjacent pallets in any direction.

Fig. 13 shows the upper surface 124 of a pallet pallet 124 of a fork-operated pallet having an embossed structure. In this case, the embossed structure is made up of shallow perforations (a few mm deep) that extend along the surface in bands 125 and 126; the first lanes 125 and the second lanes 126 being in opposite directions. The bar rows are parallel to one side of the pallet. The embossed structure is formed by passing the plate through a heated roller having surface portions formed in a shape corresponding to the arrangement of stripes 125 and 126. The roller is rotated at such a speed and the roller is pressurized on the plate that the embossed structure of Figure 13 is formed with a predetermined length and depth of the strips.

In another embodiment of the pallet according to the invention, the pallet may be provided with microperforations in order to ensure a particularly high hygienic quality, but also to provide good aeration of the goods on the pallet.

Figure 14 illustrates another way of forming a stack of pallets according to the invention. 14 illustrates the upper surface 130 of a pallet pallet of a pallet according to the invention, which comprises a recess 131 into which the lower part or the base surface of the fastening means may be fitted / joined. These fastening means in the present embodiment are illustrated in FIGS. 7-9. Figs. In Figure 14. 7A is a dashed line showing the interface between the block (foot) of FIG. 7 and the pallet, i.e., the contour lines 132, 133 of the block. This solution provides an excellent opportunity for stacking the pallets of the present invention.

The pallet is fixed to the spacer structure of the pallet by a polishing process which provides not only adhesion between the elements of the pallet and the spacer, but also that the spacer joining the spacer elements of the pallet and its supporting surface it reliably and permanently eliminates the risk of cracks in the long term, that could help colonize and multiply microbes.

Fig. 15 is a schematic flow diagram illustrating the manner in which the polyfusion is executed by means of a heating mirror located between the three blocks 5a, 5b and 5c of a pallet 4 and spacer structure supporting it from the supporting surface, the blocks resting on the platform 10.

The blocks 5a-5c are arranged on the work platform with spacing and orientation corresponding to their final position on the finished pallet, and the heater 8 is located on the blocks 5a-5c.

The heater 8 has a base body 20 which is more or less thermally insulated. On the lower surface of the base body 20, the heating elements 8a ', 8b' and 8c 'are arranged such that the arrangement corresponds to the position or placement of the blocks 5a, 5b and 5c. The heating elements 8a, 8b and 8c on the upper surface of the base body 20 of the heating apparatus 8 are also arranged in a similar manner, that is, to correspond to the arrangement of the blocks 5a, 5b and 5c. The energy supply system and the type of heating elements are not the subject of the present invention and are therefore not illustrated in detail.

For example, blocks 5a-5c and other elements of the pallet may be made of polypropylene, and the surface areas to be melted are heated to a temperature of 215 ° C to 235 ° C.

The heating elements 8a-8c 'have a dimension perpendicular to the plane of the drawing, i.e. a size corresponding to the thickness of the pallet 4, which allows the geometrically suitable surface portions to be heated where the lower surface of the pallet 4 covers the blocks 5a-5c. they do not melt; the heater 8 is then removed

- retracting - and lowering the pallet 4, bringing the heated regions of the pallet 4 into contact with the blocks 5a-5c.

Sufficient pressure is then applied to ensure that the pallet 4 is held in position in the desired position by the blocks 5a to 5c, in which position these pallet elements overlap and the heated surface portions are cooled and allowed to cool. pressure is maintained to ensure excellent quality of connections between the contacting surfaces of the elements. Thereafter, the burr formed by the pressure applied to the molten material in the heated regions is preferably removed.

Those skilled in the art will be able to use solutions other than the fusion process described above to partially assemble the pallet elements.

With respect to the present invention, only one embodiment has been described above, but it is to be understood that the scope is not limited to the geometric forms shown in the figures.

The upper surface of the pallet may have a lattice structure formed by an embossing technology, which may be formed by a heat-printing technique. The pallet may contain microperforations. Such pallets are particularly advantageous in the cheese industry.

The invention is, of course, not limited to the geometric shape and other details of the pallet board as described above and in particular to the number of guide members or blocks acting as such, but may be practiced in various ways within the scope of the claims.