FR2466402A1 - Cardboard pallet made from box beams - mounted on tubular legs on a base and having tubes in between the edge beams - Google Patents

Abstract

The cardboard pallet has three base strips (2) which support a number of tubes (2a,2b) at the corners, and a tube centrally along the base strip. The tubes are covered with end plates (8) which support pairs of box beams (3a,3b) across the ends and longitudinal beams (4,5,6). The space in between the beams is filled with tubes (6) located side by side. The entire pallet is covered with a top plate (10). The pallet is assembled with glue and may have box beams instead of tubes in between the edge beams.

Description

The present invention E '?. t: relating to a cardboard-based handling pallet which can be discarded after use and which is intended to replace the usual handling pallets made of wood.

The handling pallets already used and which are made of plastic, wood or agglomerated material from wood fibers, generally have an excessively high cost price or a lack of solidity for an excessive weight. The wooden pallets used in the usual way have a horizontal plate raised above the ground by means of a certain number of support members forming feet which make it possible to lift and. transport the pallets by inserting the fork of a forklift or equivalent device under the horizontal platform. I1 is advantageous to be able to introduce the fork of the forklift on the four sides of the pallet which is generally rectangular, which allows the greatest flexibility of handling.

We also know of handling pallets made of cardboard. For these pallets of known type we encounter the same types of difficulty, to which is added the resistance to humidity. To ensure sufficient resistance to compression of the cardboard pallet trays, trays have already been produced having a honeycomb structure produced by the assembly of. vertical tubes of polygonal section between two horizontal plates. However, in such an embodiment, there are difficulties in manufacturing the honeycomb structure, as well as poor resistance to bending when, for example, the pallet is only supported by two of its edges, for example during storage suspended on slides
r lateral
Also known, for example, by patents.

French 2,236,741 and 1,586,316, cardboard pallets produced using the assembly of a plurality of horizontal cardboard tubes of circular section. These pallets, which can only be taken from two sides, are more resistant in principle. to bending forces than the pallets of the previous type, but generally have poor resistance to compression. The use of corrugated cardboard in pallets of this type does not improve their characteristics and does not generally make it possible to obtain a suitable resistance to humidity unless provision is made for additional coatings which increase the cost price.

The subject of the present invention is the production of a cardboard-based handling pallet, therefore very light compared to conventional wooden pallets and which has great resistance to both compressive and bending forces, taking into account of the particular assembly, of the various elements which constitute it.

Furthermore, the subject of the invention is also such a pallet which has a natural resistance to humidity greater than most cardboard pallets of the conventional type.

The cardboard-based handling pallet according to the invention comprises a tray placed on a support plate provided with feet and reinforced by cardboard tubes.

According to the invention, the tray comprises a frame, the sides of which are produced using cardboard frame tubes with axes parallel to the tray and assembled on the support plate perpendicularly to each other so as to produce a border frame of the tray. Means are also fixed to the support plate inside the border frame to maintain the structure of the reinforcement tubes and prevent their deformation, in particular by crushing in the event of compression or bending forces exerted on the tray. Each of the reinforcing tubes is further supported by at least two feet which provide a spacing of the plate relative to the ground allowing the recovery and handling of the pallet of the invention from its four sides.

In a preferred embodiment, at least one additional cardboard reinforcing tube is also arranged parallel to two of the sides of the border frame in the middle area of the tray and preferably parallel to the long side of the pallet in the case where it is rectangular.

 The reinforcing tubes are preferably assembled in pairs, for example by gluing, which strengthens their structure by lining the wall at the junction between two tubes forming a pair.

 According to a preferred embodiment of the invention, the reinforcing tubes are made of spiral cardboard or convolute, by winding a plurality of laminated turns. These tubes are preferably of polygonal section, for example square. Thanks to such a method of manufacturing armature tubes, superimposing several turns laminated to each other, a very high natural resistance to humidity is obtained, resistance which can be further increased if desired by spraying with suitable products such as waxes or paraffins.

 The means ensuring the maintenance of the structure of the tubes of the border frame are preferably produced by means of a plurality of portions of cardboard tubes with axes perpendicular to the plane of the plate, these portions of tubes being arranged inside the border frame and in contact by their periphery with the internal edges of said frame. These tube portions can advantageously be of circular section. This internal filling of the frame considerably improves the compressive and flexural strength of the entire pallet, both by its own strength and by the effect of maintaining the initial structure of the reinforcing tubes.

 At the intersections of the armature tubes with axes parallel to the plate forming the border frame, are preferably arranged two feet, each of which cooperates respectively with one of the armature tubes defining a side of the border frame. Each armature tube is therefore supported near its end by an independent foot.

The feet can consist of a portion of cardboard tube with an axis perpendicular to the tray. They can be produced like reinforcing tubes in spiral cardboard or in a variant made of synthetic plastic, for example honeycombed. The feet are fixed to the underside of the platform preferably by means of support plates intended to distribute the compression forces.

A sole in the form of a cardboard strip is also preferably fixed under the feet aligned opposite the edges of the tray.

 The feet can also be surrounded by a cardboard envelope, the upper face of which comes into contact with the support plate. In this embodiment, a better distribution of forces is obtained and the fixing by bonding is improved by increasing the area of adhesive.

The portions of tubes arranged on the tray, as well as the portions of tubes serving as feet, can be produced like the armored tubes made of spiral cardboard by winding a plurality of laminated turns.

The invention will be better understood on studying the detailed description of two embodiments described by way of non-limiting examples and illustrated by the appended drawings in which
Figure 1 shows a perspective view of a pallet according to the invention;
Figure 2 is a top view of the pallet of Figure 1;
Figure 3 is a sectional view along III-III of Figure 2;
Figure 4 is a sectional view similar to Figure 3 showing an alternative embodiment of the legs of the pallet; and
Figure 5 is a perspective view similar to Figure 1 of a variant pallet according to the invention.

 As shown in Figures 1 to 3, the handling pallet according to the invention comprises a horizontal support plate 1 maintained at a certain distance from the ground by feet 2, the assembly being produced by means of cardboard.

The plate 1 of generally rectangular shape comprises a border frame, the sides of which are produced using pairs of reinforcing tubes 3 and 4, the pairs of tubes 3 forming the short sides of the rectangle extending over the entire width. of the plate 1. The pairs of tubes 4 forming the major part of the long sides of the rectangular plate 1, are arranged perpendicular to the pairs of tubes 3 and come into contact by their ends with the internal faces of the pairs of tubes 3. Each of the tubes 3a, 3b and 4a, 4b which constitute the aforementioned pairs of reinforcing tubes is constituted by a square section tube made of spiral cardboard which comprises a winding of a plurality of turns laminated one on the other. preferably manufactured continuously, according to a process described in French patent No. 69 23 927 which makes it possible to obtain a large wall thickness of the polygonal tube.

In addition, these spiral tubes obtained by winding several laminated turns, have a resistance to humidity significantly higher than that of a simple kraft cardboard.

 The tubes may have another section than that which is shown in the figures. They can in particular be of rectangular or triangular section although the square section gives in practice the best results which make it possible to ensure an excellent fixing of the two tubes between them. One could possibly consider also using reinforcement tubes of circular section provided that they are arranged in the form of a frame perpendicular to each other, the fixing being however in this case more difficult to achieve.

It will be noted that in the embodiment illustrated in FIGS. 1 to 3, the tubes constituting the pairs of tubes 3 and 4 are bonded together, so that on the bonding surface, the wall is doubled, which considerably increases the resistance. of the beam formed by the pair of tubes 3 or 4.

In the embodiment illustrated in FIGS. 1 to 3, a pair of additional reinforcing tubes 5 is arranged inside the frame parallel to the pairs of tubes 4 which constitute the long side of the rectangular plate 1. The pair of tubes 5 is constituted by the assembly, for example by gluing, of two tubes 5a and 5b of the same manufacture and of the same structure as the tubes 4a and 4b. Their length is also identical and they come into contact at their ends with the internal lateral faces of the tubes 3b of the pairs of tubes 3 constituting the short sides of the rectangular plate 1.

 Although the pair of additional reinforcing tubes 5 is arranged in this embodiment parallel to the long side of the rectangular plate, it could be envisaged to arrange it parallel to the short side. Note, however, that it is more important to strengthen the flexural strength of the plate 1 in the direction of its greatest length.

 Tube portions 6, of circular section, with axes perpendicular to the plane of the plate 1, are arranged in the frame formed by the pairs of tubes 3 and 4 and between the different pairs of armature tubes 3, 4 and 5. As can be seen in the figures, the tube portions 6 are of a suitable diameter, so that they can be arranged in two groups of two rows, on each side of the pair of central reinforcing tubes 5. The tubes 6 are in contact on a generator with each other as well as with the internal lateral faces of the various armature tubes 3, 4 and 5. The height of the tubes 6 corresponds to the thickness of the armature tubes 3, 4 and 5.

 The horizontal support plate 1 is therefore produced by assembling, preferably by gluing, armature tubes 3, 4 and 5 with axes parallel to the plane of the plate and tube portions 6 with axes perpendicular to the previous ones. The tube sections of circular section 6 can also be produced by the same spiral or convolution process as the armature tubes - -3, 4 and 5.

Thanks to the existence of the tube portions 6 which leave no void between the different armature tubes 3, 4 and 5, the latter are maintained and do not risk being crushed or deformed during a compression force. or bending, exerted on the plate 1. In addition, the tube portions 6, also participate in the compressive strength of the plate.

 The bonding of the various elements constituting the plate 1 is made on a lower support plate 7 which has the same dimensions and the same shape as the plate 1. This lower plate which serves to stabilize the plate 1 and also allows the feet to be bonded 2 can be made of compact cardboard obtained by lamination or possibly corrugated cardboard in which case it can be optionally protected against humidity.

 In the embodiment illustrated in FIGS. 1 to 3, the legs 2 are constituted by portions of tubes of circular section with a vertical axis. Each of the pairs of reinforcement tubes 3 and 4 is supported by three feet, two of which are arranged in the vicinity of the ends and the third is located in the middle zone. In the vicinity of each of the angles of the plate 1, that is to say in the vicinity of the areas of intersection of the pairs of reinforcing tubes 3 and 4, the plate 1 is therefore supported by two adjoining feet 2a and 2b. The foot 2a supports the end of the pair of tubes 3, while the foot 2b supports the end of the pair of tubes 4. In order to ensure the best possible support, the diameter of the portions of circular tubes constituting the feet 2 is preferably substantially equal to the total width of the corresponding pair of tubes 3 or 4, as can be seen in particular in FIGS. 2 and 3.

 Although the feet 2 have been shown in this embodiment, with a circular section, it will be understood that in a variant the feet could be of polygonal section. The feet can advantageously be made of cardboard and made like reinforcement tubes in a spiral or convolute in the same material as above. The feet can also be produced by several sheets of single or double-sided corrugated cardboard laminated to each other to the desired thickness. In another embodiment, the feet can also be made of plastic or wood or any other material ensuring a suitable spacing of the plate 1 relative to the ground.

Each foot 2 is bonded by means of a foot support plate 8 fixed under the lower support plate 7. The support plates 8 make it possible to better distribute the forces and improve the bonding. The support plates 8, cooperating with an individual foot 2 are of square shape, while the support plates 8a cooperating with two adjoining feet 2a and 2b are of rectangular shape.

 A strip of cardboard forming the sole 9 is also fixed under the feet 2 parallel to the pairs of reinforcing tubes 4 and 5. The soles 9 make it possible to better maintain the feet 2. Furthermore, they also participate in the resistance to bending of the entire pallet. Finally, they allow the pallets to be easily superimposed for storage.

 The pallet is completed by an upper plate 10 completely covering the plate 1 and which mainly has an external covering role. This upper plate which is glued to the plate 1 also makes it possible, however, to improve the rigidity of the assembly and to allow better holding of the different elements of the plate by additional bonding or sealing. Like the lower plate 7, the upper plate 10 can be made of compact cardboard obtained by lamination or corrugated cardboard in which case it can optionally be protected from humidity by an appropriate treatment.

The feet 2 as well as the pairs of feet 2a and 2b, can also, as shown in the embodiment illustrated in FIG. 4, be surrounded by a cardboard envelope 11 constituted by a flat folded strip and the upper face of which comes in contact with the lower support plate 7 possibly with the interposition of an additional support plate such as the plates 8.

Thanks to the existence of this envelope 11, the bearing surface for fixing the feet 2, 2a and 2b, is found to be greater. In addition, the bonding of the feet 2 is no longer only on the periphery of said feet but via the flat surface of the casing 11 which ensures better fixation both on the lower support plate 7 and on the soles 9.

 In the embodiment illustrated in the figure where the same elements have the same references, there are the pairs of reinforcement tubes 3 and 4, assembled perpendicular to each other so as to form the frame of the support plate 1. The filling elements ensuring the maintenance of the pairs of armature tubes 3 and 4, are however in this embodiment, constituted by tubes 12 identical to the armature tubes 3 and 4 arranged parallel to the pairs of tubes 4 that is that is to say parallel to the long side of the rectangular plate 1. These tubes 12 which occupy all the space left inside the frame, are glued together by their lateral faces as well as on the lateral faces of the pairs of tubes 4 and by their ends on the lateral faces of the pairs of tubes 3. They are also glued to the lower support plate 7.

 In this embodiment, it is no longer necessary to provide an upper protective plate, like the plate 10 of the embodiment of FIGS. 1 to 3 since the upper surface of the plate formed by the upper faces of the tubes 12 d the horizontal axis is full. As in the previous embodiment, the filling tubes 12 play both a specific role of resistance to compression and a role of maintaining the structure of the reinforcing tubes constituting the frame of the plate 1 during an effort of compression or bending exerted on the plate. The feet 2 which are shown here in a parallelepiped shape are arranged as in the previous embodiment, and provide a suitable spacing of the plate relative to the ground.

The filling tubes 12 can be manufactured like the reinforcing tubes 3 and 4, by winding a plurality of laminated turns.

 In the embodiments illustrated in FIGS. 6 and 7 where the same elements bear the same references, the only differences with the embodiments of FIGS. 1 to 4 relate to the angle connection between the pairs of respective reinforcing tubes forming the frame of the support plate. In the embodiment of FIG. 6, the two reinforcing tubes 13a and 13b forming the short side of the rectangular frame come by their ends into contact with the internal side wall of the end of the external reinforcing tube 14a while the the end of the internal armature tube 14b, on the contrary, comes into contact with the internal lateral wall of the end of the tube 13b. The two tubes 13a and 13b forming the short side of the frame are therefore of the same length. On the contrary, the tubes 14a and 14b-forming the long side of the frame are of different length. I1 follows that the end legs 2a located at the corners of the frame support half the end of a tube 14a and two tubes 13a and 13b. The feet 2b fully support the tubes 14a and 14b. In addition, thanks to this arrangement, the long side of the frame constituted in particular by the tube 14a which extends over the entire length of the frame is better supported by the feet 2b than in the variant of FIGS. 1 to 4.

 In the embodiment of Figure 7, the two tubes 15a, 15b constituting the short side of the frame and the two tubes 16a, 16b constituting the long side of the frame are of unequal dimensions. The end of the outer tube 16a comes into contact with the side of the end of the outer tube 15a.

The end of the inner tube 16b comes into contact with the side of the end of the inner tube 15b. The outer legs 2a partially support the ends of the three tubes 15a, 15b and 16a while the inner legs 2b support, as in the variant of FIG. 6, the two tubes 16a and 16b. In this embodiment, the two external tubes 15a and 16a are therefore better supported than in the variant of FIGS. 1 to 4.

Thanks to the particular structure of the cardboard pallet according to the invention, a resistance to bending in both directions is obtained, which makes it possible to use such a handling pallet in combination with supports provided with lateral slides or racks. Furthermore, the pallet of the invention has excellent resistance to static and dynamic compression. The use of square or rectangular reinforcing tubes allows the realization of a resistant frame easier to stick since its bearing surface is much greater than that of circular section tubes. The production of these reinforcing tubes by winding several laminated turns also makes it possible to obtain a high resistance to humidity. You can, if desired, carry out a complementary treatment against the humidity of the lower and upper plates of the tray. In the same way, it is possible to cover the reinforcement tubes with an external kraft spiral, further increasing the resistance to humidity. The soles made of compact cardboard can also be treated against humidity.

Claims (21)

 1. Cardboard-based handling pallet comprising a tray placed on a support plate provided with feet and reinforced by cardboard tubes, characterized in that the tray comprises a frame, the sides of which are produced using tubes of cardboard reinforcement with axes parallel to the plate, assembled on the support plate perpendicular to each other and means fixed on the support plate inside said frame to maintain the structure of said reinforcement tubes and avoid their deformation, each of the reinforcing tubes being supported by at least two feet.  2. Handling pallet according to claim 1, characterized in that at least one additional cardboard reinforcing tube is also arranged parallel to two sides of said frame in the middle area of the tray. 3. Handling pallet according to claim 1 or 2, characterized in that the sides of the frame are produced by the assembly of two tubes of the same section.  4. Handling pallet according to any one of the preceding claims, characterized in that the reinforcing tubes have a polygonal section and preferably square or rectangular. 5. Handling pallet according to any one of the preceding claims, characterized in that the reinforcing tubes are made of spiral cardboard or convolute by winding a plurality of turns of cardboard laminated.  6. Handling pallet according to claim 4, characterized in that the two tubes on the same side are of the same length. 7. Handling pallet according to claim 4, characterized in that the two tubes on a first side are of the same length, the two tubes on the other side being of unequal lengths the longest tube extending over the entire length of said side.  8. Handling pallet according to claim 4, characterized in that the two tubes of each. side are of unequal lengths.  9. Handling pallet according to any one of the preceding claims, characterized in that portions of tubes of axes perpendicular to the plane of the plate, are arranged inside said frame in contact by their periphery with the internal edges of the frame.  10. Handling pallet according to claim 9, characterized in that the tube portions have a circular section.  11. Pallet handling according to any one of the preceding claims, characterized in that at the intersections of the armature tubes of axes parallel to the plane of the plate forming the frame are arranged two feet each of which cooperates with at least the one of the armature tubes.  12. Handling pallet according to any one of the preceding claims, characterized in that each armature tube is supported by three feet along its length. 13. Handling pallet according to any one of the preceding claims, characterized in that the feet consist of a portion of tube with an axis perpendicular to the plate.  14. Handling pallet according to any one of the preceding claims, characterized in that the feet are fixed to the underside of the plate by means of support plates distributing the forces. 15. Handling pallet according to any one of the preceding claims, characterized in that a sole or strip of cardboard is fixed under the feet parallel to two edges of the tray.  16. Handling pallet according to any one of the preceding claims, characterized in that the feet are surrounded by a cardboard envelope the upper face of which comes into contact with the support plate.  17. Handling pallet according to any one of the preceding claims, characterized in that the feet have a circular section.  18. Handling pallet according to claim 17, characterized in that the feet are made of spiral cardboard by winding a plurality of turns of cardboard laminated.  19. Handling pallet according to any one of claims 1 to 17, characterized in that the feet are made of synthetic plastic.  20. Handling pallet according to any one of the preceding claims, characterized in that the tray is covered with an upper cardboard protective plate.  21. Handling pallet according to any one of claims 1 to 8, characterized in that cardboard tubes with axes parallel to the plate and of the same structure as the reinforcement tubes fill the interior of said frame.