US 20080141912 A1
Pallet for the movement of goods with several individual parts, which are connected to each other: A loading part 6 comprises a planar slab and the goods to be transported are placed on a loading surface 26 of the loading part. Underneath the loading part are arranged a reinforcement section 5, a frame center section 3 and a frame floor section 4. A flame protection coating of the individual parts of the pallet effects fire resistance in the event of a fire.
1. A pallet for the movement of goods, comprising:
an upper section having a loading part with a loading surface and a reinforcement section, wherein the loading surface and the reinforcement section have a material-fit connection to each other;
a frame section comprising a frame center section and a frame floor section, wherein the frame center section and the frame floor section are connected to each other;
wherein the frame center section corresponds to the size of the loading surface and, at least at its corners, has spacers, which point to the upper section and have a material-fit connection via the frame section to the upper section, wherein the spacers have end-face elevations inwardly offset stepwise, and the reinforcement section has, at its lower surface, recesses for accommodating the elevations; and
wherein the frame center section has a material-fit connection to the reinforcement section in the area of at least one of the spacers and the end-face elevations.
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The present invention relates generally to a pallet for the movement of goods.
For the transport of goods, transport pallets, especially Euro pallets, are well-known, which are traditionally made of wood. Furthermore, pallets manufactured from plastic are also common, which, in addition to having a low weight, have better resistance to aging and are better to clean in comparison to wood. Many well-known pallets, however, have a relatively low torsional rigidity. They therefore cannot be readily subjected to asymmetric heavy loads. This reduces the scope of application.
Furthermore, the problem arises in the case of plastic pallets that the plastic is flammable such that, in the event of a fire, toxic gases can develop. This, too, leads to a fundamentally undesirable restriction on the pallet's scope of application.
The object of the present invention is to create a pallet whose scope of application is increased.
The pallet described here has an upper section and a frame section, wherein the upper section has a loading part with loading surface and a reinforcement section that have a material-fit connection to each other. The frame section comprises a frame center section and a frame floor section, which likewise have a material-fit connection to one another. Furthermore, the frame center section corresponds to the size of the loading surface and, at least at its corners, has spacers which point toward the upper section and via which the frame center section is connected to the upper section. At their end faces, the spacers have elevations which are inwardly offset in steps. For accommodating these elevations, the reinforcement section has recesses at its lower surface. The frame center section likewise has a material-fit connection to the reinforcement section in the area of the end-face spacers. Alternatively or additionally, the aforementioned connection can be in the area of the elevations. The pallet in accordance with the invention is substantially torsionally stiffer than well-known pallets, because the upper section and the frame section reinforcing it are much better connected to one another. This increases its scope of application such that it is more economically applicable.
The loading part, the reinforcement section, the frame center section and the frame floor section are preferably made from plastic, especially an elastomer plastic, with a material such as polypropylene or polyethylene suitable for use. Parts made from such a plastic lend themselves readily to material-fit connections. The aforementioned connections between the parts are of a material-fit type effected by a welding method, with hot-plate welding especially suitable. Hot-plate welding is one of those heating element welding methods in which heating elements heat the contact area to be welded until the material in the areas concerned softens, and then the heating elements are removed from the heated area. The components to be welded are then positioned against each other and aligned with each other under compressive force. Material in the area to be welded deforms fluidly and, in flowing, creates the material connection. Preferably, heating is performed not as far as the melting point of the plastic, but only to above the softening point.
For the purpose of supporting the welding process, at least a first welding rib is molded on to the spacers at the end face, said rib pointing toward the reinforcement section and serving as welding material during welding of the frame center section to the reinforcement section. The first welding rib of the spacer is advantageously closely molded on at a peripheral outside edge of the spacer and points upward and away from the frame center section. The rigidity of the connection is increased by the outer welding rib.
Further, at least a second welding rib is molded on advantageously at the end face of the elevations, said rib pointing toward the reinforcement section and serving as welding material during welding of the frame center section and the reinforcement section. The first and second welding ribs both have the same alignment, which is parallel to the loading surface. Thus, the welding planes defined by the first and second welding ribs are accordingly parallel to the loading surface. The second welding rib is thereby arranged closer to the loading surface than the first welding rib. Due to this vertical offset, correspondingly offset welding regions are produced, which, through their different positioning, serve to improve retention of the elevations in the recesses. Furthermore, the lateral gap between the elevation and the recess is advantageously dimensioned, such that a part of the material of the second welding rib flows into this area in order to yield a weld at a side that is not the end face of the elevation.
In a development in the area of the recesses at the reinforcement section, at least a third welding rib for welding the frame center section to the reinforcement section is provided . Advantageously, this third welding rib is multipart. These third welding ribs are either formed as a rib-like elevations, or alternatively as incremental elevations. These third welding ribs are formed such that, during uniting of the reinforcement section and the frame center section, they press against the softened material of the second welding rib, and so flow of the material around the welding ribs is made possible. A good welded joint can be achieved by this flow around the third welding ribs. Advantageously, the material of the recess, too, and thus the third welding rib is heated, with the material able to connect well to the material of the second welding rib and the elevations. A corresponding welding process is provided for welding of the first welding rib to the reinforcement section, as well for the other aforementioned material-fit connections.
The loading part has advantageously an essentially flat surface at the upper surface and has especially the shape of a flat slab, such that the loading part can be cut out from an extruded flat slab. Since the material becomes thermoplastic during the extrusion process, clearly better values for strength are attainable than is the case for an injection molded material under given comparable material thicknesses. Thus, the loading surface, which corresponds to the surface of the loading part, has good mechanical properties, such that it is not damaged by transport goods that are placed on the loading surface.
The reinforcement section is arranged underneath the loading part. It is essentially tub-shaped, with the open side of the tub limited by the loading part. The depth of the tub, that is, the distance in the vertical direction, is a few centimeters and the tub floor forms a plane that is parallel to the loading part. At the reinforcement section in the area of the tub floor, a plurality of rib-like elevations are molded on, which point toward the loading part and are in contact with it. Furthermore, the recesses at an area of the tub floor are molded on such that the vertical ends of the recesses are in contact with the loading part.
In this regard, the reinforcement section is preferably designed such that it is manufacturable in a thermoforming process. In the thermoforming process, starting from a plastic slab, the three-dimensional structure is created, which substantially effects the stability of the upper section.
Preferably, the reinforcement section has a material-fit connection at the aforementioned contact areas with the loading part. By means of reinforcement section ribs, connections from the loading part to the reinforcement section at a plurality of points or areas are produced, which provides a three-dimensional structure, which effects high strength for the upper section of the pallet. The reinforcement section ribs, which are located between two recesses, are aligned such that they point in the longitudinal direction from one recess to the next.
The upper section preferably has a plurality of handle openings. Expediently, the connection from the loading part to the reinforcement section in the area of the handle openings is a material-fit connection. So that workers do not hurt their hands when handling the pallet, it is advantageous if the handle openings arranged in the upper section are rounded.
At the pallet, preferably an outwardly sealed transponder cavity is provided for accommodating a transponder in the area of the spacers. Furthermore, at an exterior surface of the transponder cavity, the wall thickness of the pallet is at least locally reduced. The transponder cavity is outwardly sealed in order that no harmful environmental influences, such as damp, may penetrate and damage the electronics of the transponder. Further, at an exterior side of the transponder cavity is provided an area of smaller wall thickness, which advantageously corresponds to the lower surface of the pallet, such that, for example, the material there can be removed with a knife in order that an opening may be created through which the transponder can be replaced. A replacement of this kind may be necessary if, due to technical changes, for example, new transponders or altered specifications, a transponder, which was already inserted into the transponder cavity during production of the pallet, can no longer be used. If a transponder is replaced via the window in the frame floor section, the transponder cavity can be sealed by a plastic molding compound in order that the replaced transponder may be protected from environmental influences.
Preferably, the reinforcement section in the area of its side wall has an impact reinforcement, areas of which at least are formed so as to be corrugated or ribbed. The impact reinforcement advantageously leads, starting from the floor surface of the tub-shaped form of the reinforcement section, upwardly to as far as the edges of the reinforcement section that are in contact with the loading part. The corrugations lie in a plane that is parallel to the loading surface. The shape of the impact reinforcement ensures that the impact strength is increased, a fact which is essential if the pallet experiences jerky lateral loads, for example, during transport or when grabbed by the tines of a fork-lift truck or a lifting truck.
Furthermore, handle recesses are provided advantageously at the reinforcement section. These are expediently arranged at the reinforcement section in the area of the transport openings, such that they are arranged at a slight distance from the side wall at which the impact reinforcement is molded on. The handle recesses comprise an indentation, which is at least as wide as a human hand.
Preferably, the reinforcement section has an anti-slipping rim that projects over the upper surface of the loading part and serves to limit slipping of goods present on the loading surface. The bulk of the reinforcement section is underneath the loading part in the vertical direction. However, some bar-like areas of the reinforcement section preferably are molded on such that they terminate above the loading part at the sides. Thus, for example, an interrupted bar which has a uniform height of, for example, 1 cm, can be created at the outside edge of the loading surface. Goods might slip on the loading area due to transport forces, but this slippage is limited by the anti-slipping rim. Advantageous in this regard is that the anti-slipping rim is easily producible, does not require a separate part and also lends itself to better stacking of several pallets. It is advantageous that the anti-slipping rim is formed as a component of the reinforcement section, since as such it is more readily and economically producible, a fact which would not be obtained if it were a component of the loading part, which is preferably manufactured by extrusion.
For the purpose of easy stacking of several pallets one above the other, corresponding anti-slipping rim recipients are molded on at the frame floor section, in which the anti-slipping rim of a further pallet may be accommodated. This offers advantages in the stacking of several pallets since alignment and immobilization of pallets lying one on top of the other is achieved.
The pallet has preferably four bar-like carriers in which stiffening profiles are arranged. These carriers form the framework of the frame section. The frame section has preferably four large-area rectangular floor break-throughs. In the bar-like areas, which limit the floor break-throughs, stiffening profiles can preferably be arranged. These recipient areas for the stiffening profiles are located in the area of the contact surface of the frame center section and frame floor section.
These stiffening profiles can be rectangular or square hollow sections made from a metal, especially steel, and serve to increase the torsional rigidity of the pallet. A plastic profile resistant to bending is also conceivable.
Advantageously, the stiffening profiles are provided in the frame of the frame section described by the external form of the pallet, with one profile provided per edge. A further profile can be provided in one of the edges of the central crosspiece of the frame section, as a result of which therefore four or five stiffening profiles result. The stiffening profiles can be economically inserted as individual parts into the frame sections independently of each other. They can, however, also be welded to one another, which further increases the rigidity.
The pallet has in an advantageous embodiment a coating of flame-retarding material, which is applied at least on areas of the surface of the loading part, the reinforcement section, the frame center section and/or the frame floor section. Pallets, especially plastic pallets, whose plastic material contains a flame-retarding additive, are well-known. However, incorporation of the flame-retarding material into the plastic causes the disadvantage that physical properties such as hardness and breaking strength are adversely affected. Thus it is advantageous, in contravention to convention, for the flame protection to be applied via a coating.
The pallet has, as described, a plurality of plastic parts, which have in turn a plurality of ribs. The result is a large overall surface, which can be coated accordingly. Advantageously, especially those surfaces will be provided with the coating which are exposed to little or no mechanical load. The coating can be applied both to the individual parts before welding and to the finished pallet after welding. The coating works on one hand as a direct protection for the coated plastic material since the material cannot be so easily reached by the fire. On the other, there is an advantage in the fact that, in this manner, the flame-retarding material inhibits the fire overall in the vicinity of the fire. This means that, if, for example, one part of a warehouse with the pallets is on fire, the flame-retarding material causes the fire to be generally inhibited, such that it spreads more slowly and is easier to extinguish. This also applies if interior surfaces are coated, by which is meant the surfaces between the loading part and reinforcement section and between frame center section and the frame lower section. Thus, the pallet is highly suitable in fire-risk areas or for transporting readily flammable materials.
Further, a flame-retarding material can, for example, be incorporated as a kind of foam, at least in an outwardly sealed space between the loading part and the reinforcement section and between the frame center section and the frame floor section. The aforementioned enclosed space can be between the loading part and the reinforcement section or between the frame center section and the frame floor section. A material with flame-retarding characteristics can be incorporated into both areas before the individual parts of the pallet are welded. If the pallet is in a fire, the plastic material of the pallet melts or burns and the flame-retarding material is released to thus limit burning of the pallet and the fire overall.
Coatings containing urethane are especially suitable as material for coating the surfaces of the pallet. Also, a foam that contains urethane can be incorporated into an outwardly sealed area of the pallet. Furthermore, the flame protection can also be achieved by means of inorganic flame protection agents, halogenated flame protection agents, such as those based on chromium or bromine, or organophosphorous agents or by means of nitrogen compounds.
The following drawings show the preferable embodiment, without limiting the inventive idea expressed in the claims. These and other objects, advantages, purposes and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings.
Upper section 2 has four handle openings 28, which are long enough and wide enough for a worker to put in a hand to comfortably lift the unloaded pallet. The alignment of the handle openings 28 in their length corresponds to the longitudinal direction of the rectangular pallet 1. The handle openings are arranged at the edge of the upper section 2.
As is evident from
The view of the lower side of the pallet in
At the frame center section 3 are molded on nine spacers 27, which contact its four corners, four centers of its outside edges and the center of its surface. As evident from