EP0116548A1

EP0116548A1 - A block for pallets

Info

Publication number: EP0116548A1
Application number: EP83901111A
Authority: EP
Inventors: Kurt Ake Evert Aslund
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-03-25
Filing date: 1983-03-25
Publication date: 1984-08-29
Also published as: DE3308425A1; SE432238B; SE8201894L; WO1983003398A1

Abstract

Afin d'établir des raccords fermement cloués dans des palettes comprenant des blocs, le bloc de la palette comporte un élément de fixation (5) agencé de façon à retenir fermement les clous qui traversent la palette. Ledit élément de fixation a des surfaces extérieures (6, 7) munies d'une pluralité de cavités (8, 9) agencées de façon à recevoir et à guider un clou dans l'élément de fixation (5). Le bloc de la palette est composé d'un matériau dur et indéformable capable de supporter des charges considérables, permettant d'obtenir une fixation ferme et comprenant essentiellement un matériau thermoplastique.In order to establish firmly nailed fittings in pallets comprising blocks, the pallet block comprises a fixing element (5) arranged so as to firmly hold the nails which pass through the pallet. Said fixing element has external surfaces (6, 7) provided with a plurality of cavities (8, 9) arranged so as to receive and guide a nail in the fixing element (5). The pallet block is made of a hard, non-deformable material capable of supporting considerable loads, making it possible to obtain a firm fixing and essentially comprising a thermoplastic material.

Description

A BLOCK FOR PALLETS.

The present invention relates to a block for pallets, consisting of an integral body, having predetermined height and opposing end suppor surfaces for abutment against flat structural elements of the pallet, to which the body is attached by nails or screws.

Pallets are subjected to considerable strain, particularly while pall goods are being loaded and unloaded by a fork-truck. The pallets are thereby easily damaged and must therefore be repaired or rejected. The damages can be^' extensive usually because the nail joints at the pallet blocks are too weak so that they become partially or totally loosened. This results in an unstable pallet and the nails have a tendency to work themselves out since their grip in the blocks is too loose, and the nail-heads protruding easily damage the goods being transported or stored, and even goods on other pallets coming into contact with the exposed nail-heads.

The main object of the present invention is to eliminate the above problem and to effect loading blocks enabling the manufacture of pal¬ lets having firm nail or screw joints which can be subjected to con¬ siderable strain without the nails or screws loosing their grip in the blocks.

This is achieved according to the present invention in that the body comprises one or more anchoring members having one or two exposed surfaces, said anchoring member being arranged to retain nails or screws with a firm grip, which are nailed or screwed, respectively, through one or more structural elements into the anchoring member, that one or both exposed surfaces of the anchoring member are pro¬ vided with a plurality of recesses arranged to guide a nail or screw into the anchoring member, and that the body consists of a hard, shape- -retaining material capable of withstanding considerable loads, which material provides said firm grip and substantially comprises a thermo- plastic material . The pallet block according to the present invention can be simply and quickly produced at low cost. The novel blocks provide nail or screw joints superior to the joints obtained with previously used pallet blocks.

In a preferred embodiment the exposed surfaces of the anchoring member or members are spaced from the opposite end support surfaces. Such spaces enable the nails to be free therein to bend while being guided into the anchoring member by the recesses.

The invention will be further described in the following with re- ference to the drawings in which

Fig 1 shows in perspective a sectioned pallet block according to a preferred embodiment of the invention, and

Fig 2 shows a perspective view of a pallet provided with blocks according to Figure 1.

The pallet block shown in Figure 1 consists of a cylindrical body 1 made in one piece and being in form of an H seen in longitudinal section. The body comprises a cylindrical load-supporting wall 2 of predetermined thickness forming the opposing, parallel end support surfaces 3, 4 of the body. The body also comprises an- inner, trans- verse anchoring member 5, arranged at the middle of the body seen in longitudinal direction, and made in one piece with the wall 2, thus forming a fixed partition. The anchoring member 5 is provided with free or exposed surfaces 6, 7 facing the end support surfaces 3, 4, the exposed surfaces being substantially flat and located at a predetermined and substantially the same distance from each end support surface 3, 4. The partition is thus of predetermined thick¬ ness. The block will therefore be symmetrical both transversely and longitudinally through the centre.

The anchoring member 5 is provided on both opposing surfaces 6, 7 with a plurality of recesses 8, 9, distributed uniformly over the whole surfaces and located close together to prevent the occurrence of any large, flat areas betv/een the recesses which might unfavourabl guide and deflect a nail laterally without it penetrating into the anchoring member, thereby impeding reliable anchoring of the nail in the anchoring member 5. The recesses are parallel to the longitudinal axis of the block. In the block shown the recesses 8, 9 are in the form of funnel-shaped holes with a first conical part 10 continuing into a second, substantially cylindrical portion 11. The holes in one surface may be joined to those in the opposite surface or they may extend past each other to the opposite surface. In the embodiment shown, the holes in one surface terminate before reaching those from . the other surface. The cylindrical portion 11 of the hole has a pre¬ determined diameter which is essentially less than the thickness of the nail, e.g. approximately half the thickness of the nail so that the nail is tightly clamped with a sufficiently steady grip and con¬ siderable force in the anchoring member when entering the anchoring member through one of its funnel-shaped holes in line or substantially in line with the nail and its direction of entry. The nail will there- by be effectively retained even when the pallet is subjected to con¬ siderable strain, as is the case during loading and unloading with a fork-truck.

In the embodiment shown the end support surfaces of the block are provided with a plurality of radially directed ridges 12, which have an advantageous grip-increasing effect against opposing portions of structural elements of the pallet. Figure 2 shows a pallet provided with nine blocks according to the invention. The pallet is constructed of top boards 13, 14 and supporting bottom boards 15, the top and bottom boards being permanently nailed to the plastic blocks which thus serve as spacer means forming pockets 16 for the insertion of the tongs of a fork-lift. At least two, preferably three nails 17 are used for each joint. The grip-increasing ridges 12 penetrate into the boards and prevent the block from twisting or moving. This effect is an advantage both in assembling the pallet and during use when they are subjected to lateral strain from the forks of the fork lift, for instance.

The blocks can also be used as feet for the pallet, i.e. without bot¬ tom boards, in which case the lower end of the blocks is preferably closed. In a practical, preferred embodiment, for instance, the blocks may have a standard height of 75 mm (adapted to the forks) and a dia¬ meter of about 100 mm, the anchoring member having a thickness of abou 20 mm and the body wall a thickness of about 4 mm. The recesses may be about 8 mm deep, the conical part being about 1 mm. The conical part has a maximum diameter of about 5 mm and the recesses are uniformly distributed over both surfaces with a centre distance of. about 6 mm,, thus leaving extremely small areas between the holes. Figure 1 illu¬ strates schematically the location of the recesses and in practise the surface areas between the recesses may be smaller than shown in the drawing so that the orifice edges of the holes contact each other. Even if the point of a nail first encounters one of these narrow li¬ mited surface areas, the nail will immediately be guided to an adjacen hole due to the conical orifice of the hole. The cylindrical part of the hole has a diameter of about 2 mm which is adapted to a nail with a thickness of 4 mm. A block of the embodiment described can be injec¬ tion-moulded in one piece of ABS plastic (acrylonitrile butadiene sty- rene), for instance, HD plastic (with the addition of expanding agent) and nylon, and other thermoplastic materials and mixtures thereof with equivalent tensile properties which produce a shape-retaining body capable of taking up considerable loads and giving the desired firm grip around a nail. The thermoplastic material may advantageously con¬ sist of a mixture of a large portion of reject material of thermoplas¬ tics and a small portion of fresh thermoplastic, or of only reject material .-Fillers such as sawdust, wood meal and chalk can possibly be added in suitable quantities (generally smaller quantities).

The recesses can have a depth of from 2 mm and upwards corresponding to the thickness of the anchoring member, each recess comprising an en larged orifice portion with walls inclined towards the centre of the recess and with a cross-section larger than the thickness of the nail to be used. The orifice portion preferably proceeds into a smaller hole portion which may be circular, triangular or rectangular in cros -section, the cross-section being constant or tapering away from the orifice portion. The width of the largest cross-section is then con¬ siderably smaller than the thickness of the nail to be used, i.e. 30- -70%, preferably 40-60% and most preferably about 50% of the thicknes of the nail. Such a tapering hole portion (i.e. smaller than the ori¬ fice portion) s advantageous as it facilitates the work to drive in the nail, while the desired firm grip around the nail is still achiev The nail is preferably of such a length that it extends through the entire anchoring member in order to utilize the material to a maximum extent.

Recesses extending into the anchoring member a distance, as shown in Figure 1 for instance, are advantageous from the injection moulding point of view since the recess-forming pins of the moulding tool enabl rapid cooling of the moulded body, thus considerably increasing produc tion capacity.

The shown placing of the anchoring member at the middle of the block is preferred for manufacturing reasons, but it also offers savings in material. To further increase the cooling effect during injection moul ing, and thus the production capacity, a central through-hole, for in¬ stance, having a width or diameter of 5-30 mm, may be provided. Such a ring-shaped anchoring member is sufficiently large to allow a firm nail joint, but the nailings must be made with some alignment of the nail to the position of the anchoring member.

The block may alternatively be given other cross-sections, rectangular, for instance. Another alternative includes an anchoring member arrange at a distance from each end support surface, in which case a material- -saving space is formed between the two anchoring members. To achieve the correct guiding effect for the point of the nail the external, ex¬ posed surfaces of the anchoring members are spaced at least 5 mm, for instance, suitably at least 10 mm, from the end support surfaces of the block. Such a space enables the nail to be free therein to bend while being guided into the anchoring member by a recess. In the prac¬ tical embodiment described above this space has an height of about 27,5 mm.

It has surprisingly been found that firm nail joints can be obtained even when using completely smooth, round nails with a block according to the embodiment shown. However, if desired grooved nails may be used, or nails provided with a special adhesive layer. Screws may also be used instead of nails, further increasing the strength of the joint.

Instead of being conical in shape the recesses or their orifice por¬ tion may be pyramid-shaped to provide the pairwise opposing surfaces to guide the nail in the same way as described in the correct direc¬ tion into the anchoring member. Such an embodiment enables all flat areas between the recesses to be eliminated.

Claims

C LA I MS

1. A block for pallets consisting of an integral body (1) having predetermined height and opposing end support surfaces (3, 4) for abutment against flat structural elements (14, 15) of the pallet, to which the body is attached by .nails (17) or screws, characterised in that the body comprises one or more anchoring members (5) having one or two exposed surfaces (6, 7), said anchoring member being ar¬ ranged to retain nails (17) or screws with a firm grip, which are nailed or screwed, respectively, through one or more structural ele¬ ments (13, 14, 15) into the anchoring member (5), that one or both exposed surfaces (6, 7) of the anchoring member are provided with a plurality of recesses (8, 9) arranged to guide a nail or screw into the anchoring member (5), and that the body (1) consists of a hard, shape-retaining material capable of withstanding considerable loads, which material provides said firm grip and substantially^'comprises a thermoplastic material .

2. A block according to claim 1, characterised in that the exposed surfaces (6, 7) of the anchoring member (5) or members are spaced from the opposite end support surfaces (3, 4).

3. A block according to claim 2, characterised in that the anchorin member (5) consists of a partition of predetermined thickness and is arranged in the middle of the body (1), the exposed surfaces (6, 7) of the partition being arranged at substantially the same distance from each end support surface (3, 4).

4. A block according to any of claims 1-3, characterised in that the recesses (8, 9) are uniformly distributed over the whole surface or surfaces (6, 7).

5. A block according to any of claims 1-4, characterised in that each recess consists of an enlarged orifice portion with inclined sur¬ faces with a greatest width greater than the thickness of the nail or screw.

OV.Fl

6. A block according to claim 5, characterised in that the orifice portion has the shape of a cone or a pyramid.

7. A block according to any of claims 1-4, characterised in that each recess (8, 9) consists of an enlarged orifice portion (10) with inclined surfaces and with a greatest width greater than the thickness of the nail (17) or screw, and a hole portion (11) extending from the orifice portion (10), the greatest width of the hole portion being essentially less than the thickness of the nail (17) or screw.

8. A block according to claim 7, characterised in that the orifice portion (10) is conical or pyramid-shaped and the hole portion (11) ha an inwardly tapering or constant shape, and that the hole portions (11 are substantially parallel to the vertical central axis of the body.

9. A block according to any of claims 7-8, characterised in that the hole portions (11) have a greatest width which is 30-70%, preferab ly 40-60%, and most preferred 50% of the thickness of the nail.

10. A block according to any of claims 1-9, characterised in that the end support surfaces are provided with grip-increasing means in the form of ridges (12), for instance, arranged to provide increased grip against shearing and twisting against the structural elements (14, 15) of the pallet.