EP1606178B1 - Plastic transport pallet - Google Patents

Abstract

The invention relates to a stackable plastic transport pallet. Said pallet comprises an upper face that forms an essentially level bearing surface (1) and several supporting feet (2) that are situated on the underside of the transport pallet and are hollow and open towards the upper face, in such a way that they can nest inside one another when stacked. In addition, the underside of the transport pallet is provided with reinforcement ribs (4, 8, 9, 12). Said pallet is produced from a plastic blend containing recycled plastic with the addition of organic fibres, in particular recycled PE or PP plastics with the addition of organic cellulose fibres or hemp fibres. This permits a high load-carrying capacity and a long service life to be achieved with a cost-effective use of material.

Description

The present invention relates to a stackable transport pallet made of plastic.

Transport pallets are usually in standardized dimensions, e.g. Made in the so-called Euro pallet size 1000 mm x 1200 mm or in the dimension 800 mm x 1200 mm and are often made of wood. However, such wooden pallets have a relatively high weight and - based on their own weight - a low load capacity. Furthermore, the weather resistance in outdoor storage is problematic because wood absorbs moisture, which can lead to mold and rot. Also, the stack height of wooden pallets is limited.

In addition, transport pallets made of plastic are known. However, to ensure sufficient stability even with heavy loads in this material, a quantitatively high use of high quality plastics is usually required, which makes such plastic pallets expensive and ecologically unfavorable.

DE 86 21 855 U discloses a press-fit pallet made of material made by recycling non-grade plastics.

The invention has for its object to provide a stackable plastic pallet, which is inexpensive to manufacture and can accommodate high payloads with low weight.

The solution of the above object is achieved according to the features of claim 1.

Advantageous embodiments of the invention will become apparent from the dependent claims.

In the context of the invention, the use of recycled plastics is provided with the addition of organic fibers, preferably with the addition of organic cellulose fibers. Thus, a kind of micro-reinforcement of the plastic is created by the tensile and flexural strength and thus the stability of the material is significantly improved or is. Hemp fibers can also be used as an alternative to cellulose fibers or in addition to cellulose fibers.

Suitable recycled plastics are, for example, mixtures of polyethylene and / or polypropylene and / or polycarbonates which have an impurity content of not more than 10% (volume fraction). Such plastics are available in Germany by the so-called packaging recycling in large quantities.

The cellulose fibers used preferably have an average fiber length in the range of 0.5 to 3 mm, preferably 1 to 2 mm, particularly preferably about 1.4 mm. The mean diameter is in the range of 10 to 100 microns, preferably about 60 microns. This results in a typical fiber tensile strength of at least about 1 N / mm ² .

The volume fraction of fibers is between 3% and 50%, preferably between 10% and 20%, more preferably about 15% (ie 15% fibers and 85% plastic mixture). The exact amount used depends on the quality of the recycled plastic mixture and the requirements on the payloads. The stability of the plastic material tends to increase as the proportion of cellulose fibers increases.

Fig. 1

eine perspektivische Ansicht der Oberseite einer erfindungsgemäßen Kunststoffpalette;

Fig. 2

eine perspektivische Ansicht der Unterseite einer erfindungsgemäßen Kunststoffpalette;

Fig. 3

eine nicht maßstäbliche Schnittdarstellung durch den in Tropfenform gestalteten Rand einer erfindungsgemäßen Kunststoffpalette, und

Figuren 4 und 5

Querschnittsdarstellungen der Standfüße einer erfindungsgemäßen Kunststoffpalette.

The invention will be discussed in more detail by way of example with reference to the drawings. Show it:

Fig. 1

a perspective view of the top of a plastic pallet according to the invention;

Fig. 2

a perspective view of the underside of a plastic pallet according to the invention;

Fig. 3

a not to scale sectional view through the shaped teardrop edge of a plastic pallet according to the invention, and

FIGS. 4 and 5

Cross-sectional views of the feet of a plastic pallet according to the invention.

According to Figures 1 and 2, an embodiment of a plastic pallet according to the invention has a rectangular shape (preferred dimensions: width 1000 mm, length 1200 mm or width 800 mm, length 1200 mm) with a longitudinal and a shorter side opposite the long side broadside. The top of the pallet forms a flat support surface 1 for the palletizing material to be stacked or transported. The pallet is supported by a total of nine hollow feet 2 formed integrally from the plastic material of the pallet are formed and the support surface 1 each form an opening 13.

The feet are grid-like arranged in three rows, with eight feet each at the edge of the pallet (four of them at the corners) and a base 18 are arranged centrally. Characterized in that the feet 2 are hollow and open towards the support surface 1, the pallets can be stacked, the entire stack height is reduced by the insertable into the openings 13 of an adjacent pallet feet 2 and the stability of the stack formed is increased. In the marginal gaps between the feet 2, a fork of a material handling vehicle retract or intervene on all sides, whereby the plastic pallet can be transported with load or separated from other pallets of a stack. The feet 2 have a rectangular shape, wherein the longer side is oriented in each case parallel to the longitudinal side of the plastic pallet. As a result, the gaps for the intervention of forklift trucks on the shorter side less reduced than on the long side, so that on all sides enough space for the intervention of industrial trucks remains. The feet 2 are also conically tapered downwards, so that center themselves in the pallets during a stacking process.

According to the cross-sectional representations in Figures 4 and 5, each base 2 near the bottom of the foot on the sidewalls on at least one wall on the inside a projection on which forms a stop 14 for the base of an overlying pallet. As a result, tilting of the stacked pallets is avoided and at the same time the formation of an additional air gap s between each other Stacked pallets causes, in the fork of a transport vehicle can easily intervene. In the bottom of each stand 2 each have an opening 15 is further provided, can flow through the liquid.

To improve the stability of the plastic pallet, reinforcing ribs are integrally formed from the plastic material on the underside. For this purpose, on the one hand, the edges of the pallet reinforced by edge reinforcing ribs 4, 8, whereby the edge-side feet 2 are connected and stabilized. 3, the edge reinforcing ribs 4, 8 each have a teardrop shape with a thickening edge 16 oriented toward the edge of the pallet and an edge 17 oriented toward the inside of the pallet, the curvature the edge 16 is less than that of the edge 17. This specific shaping a lifting of the pallets is facilitated in a gripping by a fork of a transport vehicle. For reasons of statics, the reinforcing ribs 4 on the broad side have a larger volume than the reinforcing ribs 8 on the longitudinal side. Furthermore, the respective middle feet of the respective sides are connected to the central base 18 via two ribs 12 arranged like a cross. For reinforcement in the longitudinal direction, two reinforcing ribs 9 are further provided between the feet.

The pallet surface also has a symmetrical hole pattern 10. As a result, on the one hand saves material, on the other hand liquids can drain from the pallet surface.

The transport pallet according to the invention can be produced very economically by extrusion of a corresponding material mixture at temperatures of 160 to 180 ° C in a closed form dockable to the extruder.

In a pallet according to the invention, static load capacities of typically 4000 kg and dynamic load capacities of about 1500 kg can be realized. The range is very simple and very inexpensive to manufacture and easily reusable. The pallet has - based on its carrying capacity - a low empty weight and can be used in a wide temperature range of -40 to 120 ° C. Furthermore, unlike wood pallets, the plastic surfaces used are hygienic and easy to clean, even in humid environments.

In order to avoid slippage of the goods located on the transport pallets according to the invention, at least the upper sides of the transport pallet preferably have an increased surface roughness. Furthermore, at the edges of the transport pallet can be formed by a few millimeters protruding edge (not shown in the drawings), which forms a stop for the resting Pallettiergut. Such a stop need not be formed continuously along the entire circumference of the pallet, but may also be recessed, for example, in the region of the most vulnerable to damage corners.

Further, additional load-bearing runners can be attached to increase the carrying capacity as needed on the underside of the pallet. These skids can be clipped by means of pins in the outlet openings 15 of the feet, with the strips parallel to the longer side of the extend rectangular feet and connect the rows of feet each with each other.

The preparation of the pallet according to the invention is preferably carried out by extrusion of the described material mixture. The extrusion is preferably carried out at 160 to 180 ° C in a closed, attachable to the extruder aluminum mold. For this purpose, the material mixture is portioned into the extruder, liquefied by heating creamy and pressed through the screw conveyor of the extruder into the aluminum mold. By adjusting the processing temperature and the conveying speed, the material can be compacted in the mold accordingly. The mold is then removed from the extruder and cooled with water for curing.

Claims (7)

1. A process for the production of a stackable transport pallet having a top side forming a substantially level support surface (1) and a plurality of support feet (2) arranged at the underside of the transport pallet, wherein the support feet are hollow and are open towards the top side, and reinforcing ribs (4, 8, 9, 12) arranged at the underside, wherein the transport pallet is produced from a plastic blend which has recycled plastics with the addition of cellulose and/or hemp fibres, characterised in that the plastic blend is portioned in an extruder, liquefied in creamy form by heating and pressed by way of the conveyor screw of the extruder directly into a closed mould and hardened there.
2. A process according to claim 1 characterised in that the plastic blend is pressed into a closed mould which is in the form of an aluminium mould, the mould is then released from the extruder and cooled with water for hardening purposes.
3. A stackable transport pallet of plastic having a top side forming a substantially level support surface (1) and a plurality of support feet (2) arranged at the underside of the transport pallet, wherein the support feet are hollow and are open towards the top side, and reinforcing ribs (4, 8, 9, 12) arranged at the underside, wherein the transport pallet comprises a plastic blend which has recycled plastics with the addition of organic fibres and wherein the transport pallet is produced by the material blend being portioned in an extruder, liquefied in creamy form by heating and pressed by way of a conveyor screw of the extruder directly into a closed mould and hardened there.
4. A transport pallet according to claim 3 characterised in that the organic fibres comprise hemp fibres.
5. A transport pallet according to claim 3 or claim 4 characterised in that the organic fibres comprise cellulose fibres.
6. A transport pallet according to at least one of claims 3 to 5 characterised in that the recycled plastics comprise polyethylene and/or polypropylene and/or polycarbonates.
7. A transport pallet according to claim 6 characterised in that the recycled plastics further comprise foreign substances with a proportion by volume of not more than 10%.

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