EP3572343B1 - Use of a plastic pallet - Google Patents

Description

Transport pallets made of wood have been known from practice for decades. In order to ensure problem-free handling worldwide, these wooden transport pallets have standardized dimensions.

Furthermore, plastic pallets are known, which are considered advantageous over wooden pallets for certain applications and to meet certain requirements. Due to the different material properties, e.g. with regard to the modulus of elasticity, the known plastic pallets deviate from the dimensions that are standardized for wooden transport pallets.

the DE 10 2013 113 336 A1 for example, relates to a plastic pallet with entry openings coated with a non-slip surface, which serve to accommodate the fork of an industrial truck. However, in the introduction it also describes a plastic pallet which has two-layer coextruded panels. On the upper side, these panels have an anti-slip layer that might not be easy to weld or glue to the base body of a plastic pallet. The underside of such a coextruded plate consists of a material that can be easily welded to the base body of the pallet. The co-extrusion process used to manufacture the two-layer panels means that the two different materials used can be permanently and reliably connected to one another. the The non-slip design of the deck of the pallets serves firstly to secure the load for the goods on the pallet and secondly to ensure stacking safety when empty pallets are stacked on top of each other. Also from the EP 0 919 483 A1 , which is regarded as the closest prior art with regard to the design of a pallet, a plastic pallet is known, the upper side of which is designed to be non-slip by means of coextruded surface elements, the deck also having cavities in which stiffening strips are arranged and which extend upwards through the coextruded surface elements are completed. Feet extend downward from the deck, with the undersides of a plurality of feet being connected by runners.

From the DE 25 54 210 A1 plastic pallets are known which have cavities or depressions on their underside. From the DE 20 2007 003 691 U1 and the the DE 20 64 131 A a plastic pallet is known in each case, which is formed from an upper part and a lower part. With the plastic pallet after the DE 20 2007 003 691 U1 either the upper part or the lower part is largely free of a milling line, which otherwise serves to compensate for a production-related offset between the upper part and the lower part.

From the DE 10 2005 003 725 A1 a plastic pallet is known which is provided with an anti-slip coating on the upper side.

From the US 2009 000 527 A1 and the EP 0 979 778 A2 plastic pallets are known which have runners with a closed underside. From the U.S. 6,216,608 B1 it is known to design the undersides of the runners with a non-slip profile, and from the WO 2008 054 219 A1 it is known to arrange non-slip material on the underside of the runners.

From the WO 2010 127 868 A1 a plastic pallet is known whose outer corners are provided with a retention profile. From the U.S. 2010 288 169 A1 is known in the pallet deck a plastic pallet to provide a receiving space for accommodating an RFID tag.

When handling pallets, conveyor systems are used in a practically unmanageable variety. This applies, for example, to industrial trucks and their design

Forks or tines, but also roller conveyors, conveyor belts, stacking and storage facilities. Since pallet handling is becoming increasingly automated, the conveyor systems are equipped with a large number of different elements that are adapted to the geometry of the pallets. These can be guiding elements, such as deflector or guide plates, or collars, for example, which are arranged on the rollers of a roller conveyor. These can be sensors that detect the presence or absence of a wooden pallet, and which can be designed, for example, as spring-loaded flaps, limit switches or the like that rest against the pallets. However, they can also be non-contact sensors that detect the presence or the correct alignment of a pallet capacitively or in the manner of a light barrier, matched to the geometry of the pallet.

Due to the dimensional differences that exist between wooden pallets and plastic pallets, plastic pallets are typically used in a closed system due to their hygienic advantages, for example in food processing or pharmaceutical industries. In this case, the conveyor technology can be adapted exactly to the dimensions of the pallet type used in this closed system.

In many cases, however, it can be desirable to use plastic pallets in other areas as well. For example, boards broken by plastic pallets or protruding nails can be avoided, which in highly automated environments are caused by deviations from the target contour range can lead to incorrect triggering of sensors or switches. Furthermore, the formation of chips and splinters can be ruled out with plastic pallets, which could otherwise be deposited in conveyor systems and impair roller conveyors, drive chains, touch sensors and similar moving elements or optical elements such as light barriers, cameras or similar optical sensors.

In particular, the highly automated environments mentioned are typically found in those industries where a very large number of pallets are used. In many cases it is not practical or economically feasible to provide all pallets in such an environment as plastic pallets.

The object of the invention is to provide a plastic pallet that can be used in an open, mixed system together with wooden pallets.

This object is achieved by using a plastic pallet according to claim 1. Advantageous configurations are described in the dependent claims.

In other words, the invention proposes, as a first measure, to design the runners of the pallet to be hollow and to arrange stiffening ribs in the runners, so that the runners are reinforced against bending. Apart from the material saving, which is economically advantageous, the hollow design of the runners also results in a weight saving, which benefits, for example, when transporting the payload of a transport vehicle available for the goods. In particular, however, the hollow construction of the runners, which is designed with stiffening ribs, enables a rigidity of the runners that enables problem-free handling of the plastic pallet, even when loaded, in a variety of different conveying, handling and storage systems.

As a further measure, it is proposed that the undersides of the runners be closed. In this way, the flexural rigidity of the runners is improved even further. In addition, sensors are often used in practice to detect the presence of a pallet in highly automated environments such as the conveyor, handling and storage systems mentioned. Such sensors have, for example, styli which protrude spring-loaded in such an environment and are pressed down against the spring action by the dead weight of the pallet or the total weight of a loaded pallet. The closed configuration of the underside of the runners ensures that the feeler pins cannot penetrate into the cavities of a hollow runner, so that the presence sensors are reliably triggered by the proposed configuration.

Furthermore, according to the proposal, cavities are also arranged in the deck. These cavities are used to accommodate stiffening strips. It is economically advantageous to use continuous profiles that can be produced inexpensively and cut to length as stiffening strips, for example in the form of solid rods. For weight reasons and reasons of saving material and in favor of improved flexural strength, hollow rods, ie tubes, can be used as stiffening strips. An even more extensive saving in material combined with high flexural strength can be made possible if closed, tubular profiles are not used, but rather open profiles, such as e.g. B. a U-profile, a wave profile o.

According to the proposal, the stiffening strips are arranged in such a way that the plastic pallet can be used both in the longitudinal direction and in is stiffened in the transverse direction so that the pallet can withstand a wide variety of bending stresses, depending on the conveyor or handling technology used to handle the pallet. For example, provision can be made to arrange the stiffening strips in the longitudinal direction and in the transverse direction of the plastic pallet in order to ensure the desired stiffening in the longitudinal and transverse directions.

Finally, according to the proposal, it is provided that the cavities in the deck of the pallet, in which the stiffening strips are arranged, are closed at the top by the coextruded surface elements provided. In this way, not only are the cavities closed on all sides in a hygienically advantageous manner, so that the formation of germ nests is prevented and the plastic pallet can also be used in hygienically demanding environments such as the food industry or the pharmaceutical industry, but also the stiffening strips themselves are protected against external influences protected.

As a result, a plastic pallet is therefore proposed which has surface elements welded both on its top side to the deck and on its underside under the runners.

The non-slip elements on the top of the pallet deck improve the secure hold of the goods on the plastic pallet. If, for example, plastic pallets are conveyed on non-driven roller conveyors, which run diagonally downwards so that the pallets are moved with the aid of gravity, there is usually a stop at the lower end of such a roller conveyor to stop the pallets at a defined position from where they for example, can be removed fully automatically. In practical tests, it has been found that the running speed of plastic pallets on such non-driven roller conveyors is greater than the running speed of wooden pallets. Accordingly, the plastic pallets hit the stop at the end of the roller conveyor at a higher speed. The anti-slip coating ensures that the goods remain reliably on the pallet even if they hit the stop.

According to the proposal, it is also provided that the plastic pallet is manufactured in a manner known per se, including the runners, and that the runners are closed off at the bottom by means of separate, so-called base plates, which are welded to the underside of the runners. In this way, economical production of the plastic pallet is supported and it is not necessary to produce the runners, for example in the form of special extruded profiles, which would provide the closed underside.

Such a base plate extends over the entire length of the runner, so that the number of parts required for the plastic pallet and the number and length of the total weld seams to be carried out can be kept lower than if the runners were closed on their underside with several base plates each .

According to the proposal, the base plate is designed to be non-slip on its underside.

If the plastic pallet is conveyed, for example, on a so-called "gravity roller conveyor" that leads diagonally downwards, then in practice such gravity roller conveyors are often provided with braking rollers. These are intended to prevent a pallet from reaching too high a speed until it hits a stop at the lower end of the gravity roller conveyor, which can be designed, for example, as a steel strip running transversely to the roller conveyor. If the speed is too high, there is a risk that the load will slip on the pallet or fall off the pallet when the pallet hits the stop. the The excellent sliding properties of a plastic pallet can contribute to the braking rollers mentioned having less of an effect on the plastic pallet than on a wooden pallet. Due to the non-slip design of the base plate on its underside, the slip behavior of the plastic pallet can be matched to the slip behavior of a wooden pallet.

Advantageously, the underside of the base plate can be designed to be non-slip in the desired manner by means of a non-slip coating. In this way, the same materials and the same technology can be used as is known, for example, from the non-slip design of a pallet deck. For example, a strip of slip-resistant material can be glued or welded to the bottom of the footplate, and such a strip can completely or partially cover the underside of the footplate, or can be flush with the footplate so that the underside of the footplate is flat with no downward protrusions.

The stiffening strips in the deck of the plastic pallet could, for example, be combined to form a closed, circumferential ring or run diagonally across the pallet deck. As already mentioned above, it can be particularly advantageous for the stiffening strips to run in the longitudinal and transverse directions of the plastic pallet.

The stiffening strips can be made of particularly light materials such as CFRP or similar composite materials such as GRP. In practice, the use of stiffening strips made of steel has proven excellent due to the economically available commercially available semi-finished products from which the stiffening strips can be cut to fit. In particular, the use of pipes allows high flexural rigidity with low weight of the stiffening strips.

Alternatively, the stiffening strips can be designed as double T-profiles, which also represent an advantageous embodiment with regard to the economically available commercially available semi-finished products, with the advantages of a high flexural rigidity of the stiffening strips.

Advantageously, the runners can be designed without lateral indentations. Such lateral indentations are often to be found in the area of the runners in plastic pallets, for example because of the economic and weight advantages associated with the saving of material. In the case of wooden pallets, on the other hand, a continuous board with the same cross-section throughout is typically used as a skid. In a number of system environments, therefore, elements are provided which lie against the side of the runner. On the one hand, this can be guide elements, such as guide rollers, deflector plates or the like, to guide the pallet in the conveyor system, or it can be sensor rods, rollers, light barriers or similar sensors to detect the presence of a pallet in an automated to detect the environment. Due to the fact that the plastic pallet also has indentation-free skids, this plastic pallet can in many cases be used in mixed operation with wooden pallets where the system environment has corresponding elements which scan the skids laterally.

For the same reasons, it can advantageously be provided that the side edges of the deck are closed.

Openings, which pass through the deck from top to bottom, can advantageously be arranged in the deck of the plastic pallet. In this way it can be avoided that standing water accumulates on the pallet deck and the goods standing in a puddle that has formed on the top of the pallet deck for a long time. For reasons of hygiene, the openings are harmless, as they pass through the pallet deck and are therefore not scooping openings, but can be flushed through without any problems when cleaning the pallet.

Likewise, it can advantageously be provided that the pallet deck is heavily ribbed on its underside in order to ensure a correspondingly high flexural rigidity of the pallet. If these ribs result in cavities that are open at the bottom, then these do not represent any scooping openings in the pallet, since they are open at the bottom, so that they are hygienically harmless. In addition, these recesses, which are open at the bottom, can also be easily reached when cleaning the pallet and can be rinsed accordingly.

The anti-slip surface elements provided according to the proposal on the upper side of the pallet deck can advantageously be arranged in such a way, for example in the form of longitudinal and transverse strips, that there is a maximum spacing of 15 cm between adjacent strips. Ultimately, a non-slip design of the upper side of the pallet deck is advantageous in which areas free of the non-slip coating have a maximum diameter of 15 cm. This ensures that even comparatively smaller containers always stand reliably on a non-slip part of the pallet deck and that the desired load securing of the goods on the pallet is achieved.

Provision can advantageously be made for one foot of the pallet to be provided with a retention profile, ie with a profile which secures film packaging running around the pallet, for example a shrink film, against lifting forces. Therefore, such retention profiling is provided in an outer corner of the pallet, since in the area of the four corners the holding forces of the film are greatest. In particular, it can advantageously be provided that such retention profiles are provided on two opposite feet, and particularly advantageously a particularly reliable hold of the film packaging can be ensured by all four feet in the outer corners of the pallet being provided with such a retention profile. In order to secure the film packaging against forces lifting upwards, these profiles can be provided, for example, in the form of knobs. A configuration of the retention profiling that is particularly advantageous against damage can be achieved in that horizontally running notches are introduced into the outer corner area of the foot. This avoids profiling elements protruding outwards, which would be particularly vulnerable to mechanical damage. The shrink films typically used as film packaging pull themselves into the indentations mentioned, so that the desired hold for the film packaging, which is aimed for by the retention profile, can be reliably achieved.

In order to ensure the unrestricted possible uses of the proposed plastic pallet in mixed operation together with wooden pallets, provision can be made for the plastic pallet to comply with the dimensions of a wooden pallet, as specified in UIC Code 435-2. Compared to the typical construction of a wooden pallet, where the feet often have larger cross-sectional dimensions than the feet of a wooden pallet, compliance with this Code ensures that all conveyance, handling and storage systems adapted to the use of wooden pallets also allow the use of the plastic pallets designed according to the proposal. A plastic pallet designed in this way can therefore not only be used in certain system environments together with wooden pallets in mixed operation, but actually in all system environments intended for handling wooden pallets. This also applies, for example, to compliance with the corresponding height dimensions of the plastic pallet, with the plastic pallets known from practice typically having a greater height than the wooden pallets corresponding to the standard mentioned. The standard mentioned, namely the UIC Code 435-2, Section V, in the 8th edition of May 2005 describes the dimensions of the entire pallet as well as its individual components as a quality standard for a European four-way flat pallet with the dimensions 800 x 1200 mm the associated respective tolerances for a wooden pallet.

A proposed pallet can be used with existing conveyor technology without an exact dimensional adjustment of the conveyor technology.

An exemplary embodiment of a proposed plastic pallet is explained in more detail below with reference to the purely schematic representations.

Fig. 1

eine perspektivische Ansicht von oben auf die Kunststoffpalette

Fig. 2

eine perspektivische Ansicht von unten auf dieselbe Palette,

Fig. 3

eine Ansicht ähnlich Fig. 1, jedoch vor dem Aufschweißen rutschhemmender Flächenelemente,

Fig. 4

eine Ansicht ähnlich Fig. 3, auf den vergrößert dargestellten Eckbereich der Palette, mit einem Hohlraum zur Aufnahme eines RFID-Tags.

while showing

1

a perspective view from above of the plastic pallet

2

a perspective view from below of the same pallet,

3

a view similar 1 , but before the welding of non-slip surface elements,

4

a view similar 3 , on the enlarged corner area of the pallet, with a cavity to accommodate an RFID tag.

In the drawings, 1 denotes a plastic pallet as a whole, which has a deck 2, a plurality of feet 3 and runners 4, with one runner 4 connecting three feet 3 to one another.

On the upper side of the deck 2 there are planar elements 5 in the form of elongate strips, these strips having been cut from co-extruded sheets. The plates and accordingly the surface elements 5 have two different materials, namely a non-slip material on the upper side and a material on the lower side which is welded to a base body 6 of the plastic pallet 1 . The base body 6 forms parts of the deck 2 including a frame surrounding the surface elements 5 on the outside, as well as the feet 3 and the runners 4. The surface elements 5 are welded to this base body 6. Openings 7 are provided in the deck 2, which pass through the deck 2 and prevent the formation of standing moisture on the deck 2. In the area of the four outer corners of the plastic pallet 1, the feet 3 arranged there are each provided with horizontal notches, so that a retention profile 8 is created in each of the outer corners of these feet 3.

2 shows the plastic pallet 1 from below. It can be seen that the underside of the deck 2 is heavily ribbed and has a large number of longitudinal and transverse stiffening ribs. Furthermore, longitudinal troughs 9 can be seen on the underside of the deck 2 opposite the runners 4 . Furthermore shows 2 that the runners 4 are closed off on their underside by foot plates 10, so that the configuration of the runners 4, which are hollow and are provided with a plurality of longitudinally and transversely extending stiffening ribs, from 2 is not recognizable.

3 shows in a view similar 1 the plastic pallet 1 in perspective from above, however, the deck 2 can be seen before the surface elements 5 are welded onto the base body 6. Therefore are in 3 the ones open at the top Troughs 9 can be seen, in which square tubes made of steel are inserted as stiffening strips 11 . Apart from these three longitudinal stiffening strips 11, there are also stiffening strips 11 on the two front ends of the base body 6 in the deck 2, which are inserted into troughs 9 located there and which consist of the same basic material, namely a steel square tube, as the longitudinal stiffening strips 11.

4 shows the area of a trough 9 before inserting a stiffening strip 11 in a opposite 3 larger scale and in a second embodiment of a plastic pallet. It can be seen that not only a trough 9 is provided as a recess in the deck 2 to accommodate the stiffening strip 11, but also that a flatter recess 12 surrounding the trough 9 is provided for receiving a surface element 5, so that the anti-slip strips are almost flush can finish with the surface of deck 2. They only protrude slightly beyond the height of deck 2, for example by about 0.8 mm, so that on the one hand they are protected against mechanical damage, but on the other hand they also reliably ensure that goods on deck 2 are in contact with the non-slip Surface elements 5 comes.

Furthermore shows 4 that not only the comparatively flat depression 12 and the, in contrast, deeper trough 9 are provided, but that the trough 9 is also adjoined by a receiving space 14 which reaches even further down and is provided for receiving an RFID tag. If, after mounting the RFID tag and the stiffening strip 11, the trough 9 is closed off by inserting a surface element 5 into the recess 12 and welding it to the base body 6, both the RFID tag and the stiffening strip 11 are completely surrounded on all sides and from external influences such as B. weather conditions, optimally protected.

References:

1

plastic pallet

2

deck

3

Foot

4

skid

5

surface elements

6

body

7

openings

8th

retention profiling

9

trough

10

footplate

11

stiffening bar

12

deepening

14

recording room

Claims (14)

1. Use of a plastic pallet (1),

   • with a deck (2) that forms the upperside of the plastic pallet (1),

   • where the deck (2) incorporates surface elements (5) that are welded onto its upperside and form a slip-resistant surface layer of the deck (2),

   • where the surface elements (5) are made from a co-extruded sheet material, incorporate a slip-resistant coating on their upperside and on their underside are made from a material that is welded to a base body (6) of the plastic pallet,

   • having feet (3) that extend downwards from the deck (2)

   • and having runners (4) each of which connects the undersides of a number of feet (3),

   • where the runners (4) are designed hollow and are stiffened by means of stiffening ribs to prevent flexing,

   • and the deck (2) incorporates hollow spaces in which stiffening strips (11) are disposed,

   • which strips (11) extend the length and breadth of the plastic pallet (1) to stiffen it,

   • and where the hollow spaces are closed at the top by the co-extruded surface elements (5),

   • where the undersides of the runners (4) are unbroken,

   • where each runner (4) incorporates on its underside a welded-on base plate (10) that extends the full length of the runner (4) and is designed to be slip-resistant on its underside.

   in mixed operation together with wooden pallets in a conveyor, handling and storage system that has been adapted for the use with wooden pallets.
2. Use of a plastic pallet in accordance with claim 1, characterised in that the base plate (10) incorporates a slip-resistant coating.
3. Use of a plastic pallet in accordance with any one of the foregoing claims, characterised in that the stiffening strips (11) extend the length and breadth of the plastic pallet (1).
4. Use of a plastic pallet in accordance with any one of the foregoing claims, characterised in that the stiffening strips (11) are made from steel.
5. Use of a plastic pallet in accordance with any one of the foregoing claims, characterised in that the stiffening strips (11) are designed in the form of tubes.
6. Use of a plastic pallet in accordance with any one of claims 1 to 4, characterised in
   that the stiffening strips (11) are designed in the form of double-T profiles.
7. Use of a plastic pallet in accordance with any one of the foregoing claims, characterised in that the runners (4) are free from side recesses.
8. Use of a plastic pallet in accordance with any one of the foregoing claims, characterised in that the side edges of the deck (2) are designed without breaks.
9. Use of a plastic pallet in accordance with any one of the foregoing claims, characterised in that holes (7) are arranged in the deck (2) so as to run through the deck (2) from top to bottom.
10. Use of a plastic pallet in accordance with any one of the foregoing claims, characterised in that the slip-resistant surface elements (5) are arranged on the upperside of the deck (2) in such a way that areas that are free from slip-resistant coating have a maximum diameter of 15 cm.
11. Use of a plastic pallet in accordance with any one of the foregoing claims, characterised in that one foot (3) is provided with a retention profile (8) in an outer corner of the plastic pallet (1).
12. Use of a plastic pallet in accordance with claim 10, characterised in that each of the four feet (3) is provided with a retention profile (8) in all outer corners of the plastic pallet (1).
13. Use of a plastic pallet in accordance with any one of the foregoing claims, characterised in that the plastic pallet (1) incorporates the dimensions of a wooden pallet in accordance with UIC Code 435-2.
14. Use of a plastic pallet in accordance with any one of the foregoing claims, characterised in that the deck (2) incorporates a mounting space (14) in which an RFID tag is arranged.

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