NL9002386A - Plastic pallet - has supports tapering from wide openings and containing additional members flush with load surface - Google Patents

Abstract

The nesting plastic load pallet has a one-piece plastic platform with load-supporting surface and with a number of integral tapering supports protruding at right angles from it. Each support forms a relatively wide opening in the surface, and has a relatively small supporting end furthest from the latter. It also forms an extra supporting member extending from the supporting end and providing an additional supporting surface flush with that of the platform. The tapering supports and members allow similar pallets to be nested together in a stack.

Description

LOADBOARD

The present invention generally relates to pallets for storing and transporting goods, and in particular to nestable and stackable pallets.

Wooden pallets have been used for many years for the storage and transport of goods in and around warehouses, factory buildings and the like. In their simplest form, they consist of a square or rectangular support platform mounted on a similarly shaped base frame of elongated parts, with the outer edges of the base aligned with the edges of the support platform. The carrying platform is mounted on the base frame and connected to it by means of supports located in the corners.

In addition to providing a surface that extends above the ground surface and protects goods stored thereon from dirt and moisture, the pallets also allow for the goods to be moved by a forklift by providing there is a space between the supports between the carrying platform and the base frame.

Wooden pallets, however, are water-absorbent and can rot and mold. As a result, they have to be stored in relatively expensive, covered storage areas and in dry conditions. In addition, since they are not nestable, wooden pallets take up relatively much space when stored.

Plastic pallets are also known, which of course do not absorb water, cannot rot or become moldy, and therefore do not require the same requirements for the storage conditions as for wooden pallets. Various nestable plastic pallets are also known in the art, examples of which are described in various U.S. patents, including U.S. Patent No. 3,857,342 for a modular nestable pallet, and U.S. Patent No. 4,183,491 for a reinforced pallet, which is also nestable.

While the modular construction of the nestable pallet according to U.S. Pat. 3 * 857.342 may have certain advantages, it is necessary to assemble the pallet before use, and since it has a number of joints, such a pallet cannot carry heavy loads, so it could only be used for relatively small loads.

The reinforced pallet according to US patent 4,183,491, although nestable, is not made from one piece of plastic. It is made of a first pallet-shaped part of molded plastic which has a channel at its bottom, and a second reinforcing part of plastic which, along the channel, is fused to the first plastic part,

In U.S. patent no. 4,000,704, a nestable ship's pallet which is formed from a single piece of molded thermoplastic material is described. However, this pallet is only of limited use, since a typical pallet measuring 121.92 cm by 111.76 cm can carry a maximum static load of approximately 9,072 kg.

Furthermore, Griffin's pallet, and other conventional plastic pallets made of materials such as polypropylene or polyolefin, are not resistant to extreme temperatures. For example, above 100 ° C, pallets made of polypropylene and polyolefin tend to soften; below about -15 ° C, pallets of polypropylene and polyolefin become brittle.

In U.S. patent no. 3,211, 3H from Krabbenschmidt, a pallet for dumpable loads is described. The pallet is intended to provide a device for transporting loaded soft-walled containers, for example, for grain, the pallet also facilitating the convenient unloading of the load through the pallet. When a bag is placed on the pallet and this bag is filled, the pallet can be moved to a selected location by means of a hoist. The pallet has an opening through which the device for cutting the bottom of the bag can be passed, so that cargo can be discharged through the opening. However, the pallet for bulk loads is made from a relatively large number of parts and is not nestable.

In modern industry, the recycling of used materials is becoming increasingly popular, in order to make more efficient use of raw materials and avoid having to get rid of the waste, which is not only wasteful but also long-term damage to the environment can inflict. However, it is common for products made from recycled materials, which are waste products from manufacturing processes for relatively high-performance products, for example, products that meet certain strength requirements, to be recycled for use in products not characterized by great strength. An example of this is the use of very strong synthetic fibers as fillers in, for example, partition walls and blankets.

The present invention seeks to provide an improved, nestable, single-platform plastic pallet that overcomes the drawbacks of the prior art pallets.

Another object of the present invention is to provide a method of reusing plastic waste materials, in order to obtain a product that has similar mechanical properties as an equivalent plastic product made from unused raw materials.

To this end, according to an embodiment of the invention, there is provided a nestable plastic pallet with one platform, which is formed in one piece from plastic and has a surface which forms a load-bearing surface, the platform part also comprising a number of one-piece, taperingly formed therewith supports that project substantially at right angles to the platform portion, and each of the tapered supports forms a relatively wide opening in the platform portion and a relatively narrow bearing end spaced from the opening, further forming an additional support element protrudes from the relatively narrow support end towards the bearing surface, to form an additional bearing surface and thus provide additional support to the load carried by the pallet, the tapered supports and the additional support elements being thus formed, that the pallet can be nested on the same, different pallet.

According to an embodiment of the invention, the platform part furthermore also forms an opening through which particulate material can be discharged, which is carried in a container for bulk cargo, which rests on the pallet.

According to another embodiment of the invention, there is also provided a method of manufacturing load-bearing plastic products by recycling waste-scrap materials in plastic manufacturing processes, comprising the steps of manufacturing a sample of a batch of the waste material testing the test specimen for selected mechanical properties; determining amounts of other selected materials to be added to the batch to improve the mechanical characteristics of a product made therefrom; reprocessing the batch, together with the determined quantities of the other materials and producing a next test specimen; and repeating the steps for testing, determining and reprocessing until the chosen mechanical properties are determined in a subsequent test sample.

According to yet another embodiment of the invention, there is also provided a plastic product manufactured according to the method of the invention, wherein, in a preferred embodiment, the plastic product is a nestable plastic pallet consisting of a platform part attached to one piece is formed from plastic and has a surface that forms a loading surface, and the platform member also has a number of one-piece, tapered struts projecting substantially at right angles therefrom, each of the tapered struts having a relatively wide opening in the platform part and have a relatively narrow support end that is spaced from the opening, and further form an additional support element which protrudes from the relatively narrow support end in the direction of the bearing surface, so as to form an extra bearing surface and thus additional provide support for the load carried on the pallet, with the tapered supports and the additional support elements are shaped in such a way that the pallet can be stacked nestably on another same pallet.

For a better understanding and understanding of the present invention, a detailed description will now be made with reference to the drawings.

Fig. 1A, 1B and 1C are top, side and end views, respectively, of a nestable plastic pallet constructed according to an embodiment of the invention;

Fig. 2A, 2B and 2C show various detail views of a corner support of the pallet of FIG. IA, 1B and IC;

Fig. 3A, 3B, and 3C show, respectively, a top and bottom view, and a cross-section of the opening for unloading particulate material, of the pallet of FIG. 1A, 1B and 1C;

Fig. 4 shows an enlarged sectional view of a number of the mounting holes of the pallet of FIG. IA, 1B, and IC ',

Fig. 5A, 5B, and 5C show schematic representations of the pallet of the present invention in various load situations;

Fig. 6 shows a nested stack of some of the pallets shown in FIG. 1A-1C; and

Fig. 7 is a flowchart showing a reeylage method according to an embodiment of the invention.

In Figures 1A, 1B and 1C, which show different views of a nestable plastic pallet, generally designated 10, constructed in accordance with an embodiment of the invention. Pallet 10 is made from a single piece of molded plastic, with at least preselected mechanical properties, as described below. Pallet 10 is typically made of polycarbonate by an injection molding process, although, according to another embodiment of the invention, there is also provided a method of recycling plastic waste material for manufacturing a pallet with mechanical properties similar to that of the polycarbonate pallet 10. The recycling method is described in detail below with reference to Figs. 7

Pallet 10 has a generally rectangular, flat, single platform portion 12, which consists of a grid arrangement of elongated members 14 having an upper surface 16 that forms a bearing surface 18. Substantially at right angles, a number of tapered supports protrude from the platform 12, the corner supports of which are indicated by 20; the elongated center supports (as seen in the top view) with 22; and the square center supports with 2k. The supports are shaped to allow nesting of a number of pallets; a typical nested stack is shown in fig. 6.

In FIG. 2A-2C, each corner support 20 forms a relatively wide aperture 26 in the platform 12 and a relatively narrow end portion 28. The distance between the corner supports and the elongated dimension of the support ends 28 thereof is chosen to allow rack support As is known in the art and schematically shown in FIG. 5A, with the stretch members spaced approximately 10 to 102 cm apart. Since the opening 26 is thus relatively large, provision is also made for a tapered, substantially hollow additional support element 30, which extends from the support end 28 of the corner support 20 towards the bearing surface 18 and ends there in an additional support surface 32 to provide additional support to the load carried by the pallet and thus prevent the load from being destabilized by the presence of openings 26 in the platform.

Now see Fig. IA and 3A-3C. Platform 12 also forms a typical central, funnel-shaped opening 3, through which particulate material can be discharged, which is carried in a bulk container, which is carried by the pallet. A typical container is an octabin (not shown), but may also be a suitable typical soft-walled bulk cargo container. In use, for this purpose, a pallet carrying a suitable type of bulk cargo container containing a particulate material is lifted by a suitable hoist, forklift, etc .; when opening is in a location where the material is to be released from the container, an opening is made in the bottom of the container and the material is released through the opening 34. A typical type of particulate material used in a manufacturing process are plastic granules used in the manufacture of plastic.

It should be noted that although pallet 10 is shown with the described opening 34, the pallet according to another embodiment does not have this opening.

In Figs. 1A and 4, a pallet 10, adjacent to each corner support, has a number of small openings 36 which allow to attach to the pallet, a soft wall bulk material container, typically an octabin, with staples. It will be clear that such a provision is necessary because the surface of the plastic is relatively hard, which plastic, as mentioned before, is either polycarbonate or a material with comparable mechanical properties. As shown in the detailed cross-sectional illustration of FIG. 4, the openings 36 form circular top openings 38, so that the adjacent openings typically meet at a common maximum point 40 in the Support Face 18. This circular construction ensures that if the leg of a staple engages a surface that immediately adjacent to an opening, the leg will be forced to slide into the nearest opening.

In Figs. 5A-5C show the structural properties of the pallet of the present invention while it is rack supported and resp. under dynamic and static load conditions. At rack load (Fig. 5A), that is, when the pallet is exposed to point loads near its edges, as schematically shown at 42 and 44, a pallet constructed according to the present invention may be approximately 1.0 in size. mx 1.2 m bear an evenly distributed load (Uniformly Distributed Load) of approximately 1 ton.

With dynamic loading (Fig. 5B), that is, with loading where the pallet is exposed to point loads between its supports, such as when carried by a forklift truck, as shown schematically at 46 and 48, a pallet which can be is constructed in accordance with the present invention and has a size of about 1.0 mx 1.2 m carrying an evenly distributed load of about 2 tons.

At static load (Fig. 5C), such as when the pallet rests on a floor surface, as schematically shown at 50, a pallet constructed according to the invention and having a size of about 1.0 mx 1.2 m, can be load evenly distributed load of about 13 tons.

According to the present invention, the plastic from which the pallet 10 is formed should have a modulus of elasticity (E value) of at least 2200 MN / m2, but preferably around 2400 MN / m2, and should have a shock resistance of at least around 2.8 ftlb / inch, as determined in Izod's known notched impact test. A preferred impact resistance value of the plastic is around 6 ftlb / in.

Polycarbonate and a similar material made from recycled waste, as described below, and having mechanical properties similar to that of the polycarbonate, also have the following properties that plastic products have, and in particular pallets made therefrom that have superior superior functional properties. have properties compared to existing pallets made of polypropylene or polyolefin: polycarbonate can be used at temperatures from -40 to

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+120 C, while polypropylene and polyolefin can be used at temperatures from -15 to +100 ° C; the E value of the polycarbonate in the present invention is not less than about 2200 MN / m2, while that of polypropylene and polyolefin is about 1200 MN / m2; polycarbonate has significantly better dimensional stability (average shrinkage: 0.5 to 0.7% + 0.1%) than polyethylene and polyolefin (average shrinkage: about 2.1 # + 0.6 #); and polycarbonate pallets have been subject to load aging.

With reference to FIG. 7 »a method for manufacturing a plastic product from recycled plastic waste is now described, wherein the manufactured product has selected mechanical properties as typically defined in the previous paragraph, i.e. an E value of at least 2200 MN / m ^, and a notched impact resistance of Izod of at least 2.8 ftlb / inch, but preferably around 6 ftlb / inch.

The "raw" waste material used in the present process may be waste material from any conventional structural plastics production line, and may contain not only various types of waste, such as polycarbonate, polyethylene and glass fibers, but also materials which have been used for various phases in the production line have been dropped, such as granules and powders.

Since the waste material is usually discarded in chambers or reservoirs filled with water, the material, when removed from there, is transported to a collection point on a conventional net conveyor to allow initial water drainage.

The waste material is then placed in large bags with an open fabric, which are for instance made of polyester, so that even more water can flow away. The bags are typically transported on a pallet.

When the waste material has been brought to the beginning of the production line, it is melted and injection molded, after which, for a first test, a sample is taken and tested on the following points:

Flexural strength (modulus of elasticity);

Shock resistance according to notched impact test Izod

Melt viscosity at 260 * C

Melt flow index;

Ash content (%); and

The ratio of the present polycarbonate to the present polybutylan terephthalate and polyethylene terephthalate.

It has been found that the most important criteria are the flexural strength and the impact strength. If the tested specimen does not meet the flexural strength requirements, the batch of material from which the test specimen was made is melted again and glass fibers are added and mixed with it, either by themselves or by a polycarbonate component forms that for a selected part consist of glass fiber, for example the 900 series manufactured by General Electric Plastics BV, k600 AC, Bergen op Zoom, the Netherlands. If greater impact strength is required, a combination of polycarbonate and polyethylene terephthalate can be added and mixed with the remelted batch.

The next step in the method is to extrude another test specimen from the now enriched batch, and test this test specimen. If it is found that the test sample does not meet the predefined criteria, additional amounts of the additives are added to the batch depending on the criterion that was not met and the extent of the lack of the test sample. If it is established that the set criteria are met, the manufacture of the pallet (or other product) can be started.

If the material does not yet meet the selected criteria, but is still contaminated, it can be pelletized, as is known in the art, so that it is possible to at least partially separate the contaminants by sieving or by weight separation or by water or centrifugation.

In the manufacturing process, a blowing agent, as is known in conventional industrial injection molding processes, can be added to reduce the density of the final product.

It is to be understood that while the above-described manufacturing method using recycled materials is particularly suitable for manufacturing pallets 10 of the present invention (Fig. 1-6), its application is not limited to the manufacture of such articles. Rather, the method is directed to the production of any plastic product from recycled plastic waste, the product manufactured having at least selected minimal mechanical and structural properties.

It will also be apparent to those skilled in the art that the scope of the present invention is not limited to what has been particularly shown and described above. In contrast, the scope of the present invention is limited only by the following claims:

Claims (25)

A nestable plastic pallet consisting of: i a one-piece platform part formed of plastic and having a surface that forms a load-bearing surface, said platform part also having a number of one-piece, tapered supports, which mainly protrude at right angles therefrom, each of the tapered supports forming a relatively wide opening i in said platform portion and a relatively small support end spaced from said opening, further forming an additional support element extending from said relatively small support end extends in the direction of said support surface to form an additional support surface and thus provide additional support to a load carried on said pallet, said tapered supports and additional support elements being formed such that said pallet can be stacked on another same pallet. 2. Pallet according to claim 1, wherein said platform part also forms an opening through which corpuscular material can be discharged, which is carried in a container for bulk material, which is carried by said pallet. Pallet according to claim 2, wherein said opening is centered and funnel-shaped. Pallet according to any one of the preceding claims, wherein said pallet is made of a plastic with a relatively hard surface and has a number of holes to enable a soft-walled container for bulkable cargo to be attached to said pallet with staples. Pallet according to any of the preceding claims, which is functional to carry a load on a rack of up to about 1 ton. 6. Pallet according to claim 5, which is also functional for carrying a static load of approximately 13 tons. The pallet according to claim 6, which is also functional for carrying a dynamic load of up to about 2 tons. Pallet according to any of the preceding claims, which is made of molded plastic which has a modulus of elasticity of at least 2200 MN / m2. The pallet according to claim 8, which is made of a plastic material which also has an impact resistance according to the notched impact test of Izod of at least 2.8 ftlb / inch. Pallet according to any of the preceding claims, which is made of polycarbonate. Pallet according to any one of the preceding claims, which is made from recycled waste products from plastic production processes. 12. Method for manufacturing load-bearing plastic products by recycling waste materials from a plastic manufacturing process, comprising the following steps: manufacturing a test sample from a batch of the waste material; testing said test specimen for selected mechanical properties; determining the amounts of additional selected materials to be added to the batch to improve the mechanical properties of a product made therefrom; the reprocessing of the batch together with the determined quantities of materials and the production of a subsequent test specimen; and repeating said steps for testing, determination and reprocessing, until the selected mechanical properties are detected in a subsequent test sample. The method of claim 12, wherein said manufacturing step consists of the steps of mixing and extruding said waste materials. The method of claim 13, wherein said step of testing comprises the step of testing the test specimen for its modulus of elasticity and its impact strength. The method of claim 14, wherein said testing step comprises a substep for testing the test sample for an elastic modulus of at least 2200 MN / m 2. The method of claim 15, wherein said testing step also comprises the substep for testing the test specimen for impact resistance according to the notched impact test of Izod of at least 2.8 ftlb / inch. Plastic product according to the method of any one of claims I2-I5. A plastic product according to claim 17, wherein said product is a nestable pallet. A plastic product according to claim 18, wherein said nestable plastic comprises: a one-piece platform part formed of a plastic and having a surface that forms a load-bearing surface, said platform part also comprising a number of one-piece formed therewith, tapered struts projecting substantially at right angles therefrom, each of the tapered struts forming a relatively wide opening in said platform portion and a relatively narrow support end spaced from said opening, and further an additional support member, which protrudes from said narrow support end, toward said support surface to form an additional support surface and thus provide additional support to a load carried by said pallet, thereby tapered supports and additional support elements are configured to allow nestable stacking of said pallet with another same pallet to make. Plastic product according to claim 19, wherein said platform part also forms an opening through which particulate material can be unloaded, which is carried in a container for bulk material, which rests on said pallet. A plastic product according to claim 20, wherein said opening is in the center and has a funnel shape. A plastic product according to any one of claims 19 to 21, wherein said pallet is made of relatively hard plastic and has a plurality of holes allowing a soft-walled bulk container to be attached to said pallet by by means of staples. Plastic product according to any one of claims 19 to 22, which is functional to carry a load on a rack of about 1 ton. A plastic product according to claim 23, which is also functional to carry a static load of about 13 tons. Plastic product according to claim 24, which is also functional to carry a dynamic load of about 2 tons.