Pallet made of corrugated cardboard

Abstract: Pallet with at least one layer of corrugated cardboard able to form the loading surface (2) of the board in which openings (3) are obtained, in correspondence to the opportunely dislocated zones, with fins (4) distributed along the edge forming a type of rim, respective tubular elements (5) destined to constitute the support feet of said board are coupled to said fins (4), said fins (4) being retained, with the interposition of suitable glues, between each tubular element (5) and a respective coaxial locking coupling (6) to said tubular element (5).

Description: The present invention has a board in corrugated cardboard as object. As already noted, boards used as platforms for transport and movement of goods have somewhat high costs both for the choice of material used (generally wood), and that for relative complexity of the assembling. Additionally the recycling of material of the unused platforms is difficult to carry out. The technical task of the present invention is to propose a platform having a sturdy structure using cardboard layers, in particular corrugated cardboard. In the field of such task an aim of the present invention constitutes the realization of a board that results in a simpler assembly and therefore economically more advantageous. US-A-2 507 588 (BRANDON), discloses a pallet made up with corrugated cardboard wherein from a cardboard flat surface a plurality of cylindrical legs are obtained by radially die-cutting holing and downwards bending the respective cardboard cut triangular fins, to glue them as a crown between two tubular reinforcing supports to realize the respective legs. This solution has the problem of liability of the respective legs and the surface of the pallet is holed. DE-U-91 01 921 (KAWELL GMBH) discloses a cardboard pallet according to the first part of the claim obtained by assembly of two cardboard panels, inserted one over the other, the upper one being a couple of panels and having their fins constrained between an external tubular leg and an internal reinforcing ring, the latter one having the length of the respective fins; the lower panel having respective similar crown holes and the downward bent triangular fins being inserted and glued outside said external tubular leg, this lower panel being more extended in surface than the upper couple and the respective opposed exceeding strips are overturning-bent above the upper one, to obtain an assembled pallet. This solution is compact and robust but the respective legs are not strong enough to support the stresses of pallet moving, in particular a very good and strong platform is realized but the respective legs are not reliable. US-A-4 850 284 (DEGROOT) discloses a cardboard pallet similar to the previous ones wherein reinforcing cardboard portions are applied under the respective legs using the same crown holes with the triangular bending fins insertion between two tubular reinforcing supports having the same length, the latter ones being the mullion structure of each leg. This solution solves part of the problem of the legs reinforcement, but a skilled person knows that very important stresses have to support the pallets in their moving and load transporting, in particular the respective forks of the forklift truck, easily damage the pallet legs, because the external and internal tubular structure having space between them under the crown insertion strongly reduce the peak load resistance, and if one uses two opposed crowns one for the upper panel and one for the lower panel, the solution suggested provides obligatorily the use of two internal reinforcing rings, one inserted from above and one inserted from below. In the last solution the use of two internal rings strongly reduce the strength of the respective leg and the peak load is strongly reduced because the two legs can superimpose one into the other. In particular DE-U-91 01 921 (KAWELL GMBH) is considered the most robust solution as regards its platform structure, but it falls in the respective tubular legs that are realized with a single tubular mullion structure. In fact it is obvious to increase the thickness of the single tubular leg to support a peak load, the suggested structure facilitates the tubular legs to bend, in particular because the external glued crown of the lower panel is not able to give a real reinforced reaction. The scope of this invention is to obviate said drawbacks using the teachings of DE-U-91 01 921 (KAWELL GMBH) but realising a new solution with certain selected features disclosed in US-A-4 850 284 (DEGROOT). The problem is solved as claimed according to the claim by a pallet made up with corrugated cardboard, wherein from a cardboard flat surface, a plurality of cylindrical legs are obtained by radially die-cut holing and downwards bending respective cardboard-cut triangular fins, to form an upside-down crown, to glue it inside and outside a tubular reinforcing ring, and wherein the pallet is made by assembling two cardboards one of them being larger and the exceeding portion/s being folded up to cover respective holes, the crown of upper cardboard being inserted internally to a main leg tubular mullion structure and the crown of the lower cardboard being inserted externally to said main leg tubular mullion structure, the crown of said upper cardboard being constrained to said main leg tubular mullion structure by internal constraining tubular reinforcing piece, characterised in that: said internal constraining ring has the length of said main leg tubular mullion structure plus the wall thickness of the upper cardboard; an external tubular reinforcing element, having the length of said main leg tubular mullion structure minus the wall thickness of the lower cardboard, is applied and wherein the respective upper cardboard foil is larger than the pallet and bent 180° on its surface to cover the respective hollows of the legs; the obtained tubular structured legs are connected in rows on their bottom one to the other in the same way with similar crown-hole-cut cardboard cross-pieces. In this way a strong cardboard pallet is obtained. Further particularity of the present invention will result mainly from the description that follows on the basis of the attached drawing, in which: Fig. 1 shows a perspective view of a well known cardboard pallet that can be obtained with this invention; Fig. 2 shows a view according to the section surface II-II of Fig. 3, 4 show the schematized variations of well known prior art; Fig.5 discloses a cross section of a leg of the pallet feature according to the claim of this invention without the opposed upside-down crown fins of the lower cardboard connecting the bottom of the tubular legs. Fig. 6 shows a perspective view of a cardboard pallet according to the invention wherein cardboard side extensions are overturning-bent to cover the hollowed surface; Initially referring to figure 1, 1 generically indicates the cardboard pallet according to the present invention and prior art. Fig.6 discloses the solution of the present invention combining features of DE-U-91 01 921 (KAWELL GMBH) with features relating to the bottom legs connection disclosed in US-A-4 850 284 (DEGROOT). Figs 2, 3 and 5 indicate the main reinforcing tubular mullion structure to constitute a leg 5L. According to prior art the pallet is made up of one loading surface 2 of rectangular form constituted by a layer of corrugated cardboard, single or multi-layer depending on the resistance that one wishes to confer to the pallet. In the loading surface, in correspondence to the legs, openings (holes) 3 are provided by means of star die cuttings to obtain triangular fins 4 to be bent perpendicularly to the surface of the respective loading deck surface, in order that the fins form a type of rim like an upside-down crown along the edge of the openings 3. The triangular fins 4 are inserted inside or outside the cylindrical tubular elements 5 constituting the support feet (leg) of the cardboard pallet. The fins are solidarized to the tubular elements 5 by means of the interposition of suitable glue to apply with hot or cold processing. Well known within the prior art, to assure a greater adhesion of fins 4 to the tubular elements 5, tubular reinforcing supports locking couplings 6 are provided that inserted in the openings 3 push the fins 4 against the internal wall of the tubular elements 5, avoiding the possible detachment. Opportunely the top of the tubular elements 5 abut under the layer in order that the fins 4 are not stressed with cuts from the heavy load on the board. Figure 3 shows a variation in well known prior art in which two tubular elements having approximately the same length 5, 7 are used to clamp between them the respective crown fins 4. Between the internal tube 7 and the external main tubular mullion leg structure 5 an interspace remains in which a complementary shell section may be inserted. In the form of fig. 4 the tubular element 8, having the function of board foot support, is inserted inside the rim of the fins, whilst the locking coupling 9 is on the outside, this solution being similar to DE-U-91 01 921 (KAWELL GMBH) prior art and having the same defect of non resistance of the outside glued crown 9. In the cardboard pallet, according to the invention, a loading surface composed of two superimposed cardboards is used (See fig.5), Under the upper cardboard 2 a further reinforcing cardboard 10 is applied, the respective crown fins 11 being constrained and locked by an external tubular reinforcing element 12 having the height as the main tubular mullion structure 5M minus the thickness of the lower cardboard, while the crown fins 4 of the upper cardboard 2 are internally inserted and blocked by an internal constraining tubular shell 7 having the height of said main mullion tubular structure 5M plus the thickness of the upper cardboard. In this way a real reinforced pallet with further reinforced legs is obtained. Figure 6 shows that the upper layer (2) has two edges 13 and 14 reversible on the same layer for the closing of the openings 3. The edges 13 and 14 are obtained from the same layer 2 by means of weakened lines that allow its turning. Naturally it is also possible to provide a single edge of the sizes of the layer, in place of two. In order to confer greater sturdiness at the legs 5L cross-cardboard pieces 15 are provided to connect from the bottom rows of tubular legs 5 between them in the same way. Analogously with that provided for loading surface, every cross-piece 15 is composed of a single or multi-layered corrugated cardboard strip in which, by means of star incisions (cuttings), fins are obtained which are able to be refolded and secured inside the tubes of the tubular legs 5 L. The cross-pieces 15, other than representing a valid stiffening against the bending stresses due to the load, avoid the support feet sticking into the soil during the dragging movements. The tubular elements could be of polygonal section. In the preferred solution tubular elements are realized with spiralled cardboard.

Claims: A pallet made-up with corrugated cardboard (1), wherein from a cardboard flat surface (2) a plurality of cylindrical legs (5L) are obtained by radially die-cutting holing and downwards bending respective cardboard-cut triangular fins, to form an upside-down crown (4), to glue it inside and outside a tubular reinforcing ring, and wherein the pallet is made by assembling two cardboards (2,10) one of them being larger and the exceeding portion/s being folded up to cover respective holes, the crown of upper cardboard (2) being inserted internally to a main leg tubular mullion structure (5M) and the crown of the lower cardboard (10;11) being inserted externally to said main leg tubular mullion structure (5M), the crown of said upper cardboard (2) being constrained to said main leg tubular mullion structure (5M) by internal constraining tubular reinforcing piece (7), characterised in that said internal constraining ring (7) has the length of said main leg tubular mullion structure (5M) plus the wall thickness of the upper cardboard (2); an external tubular reinforcing element (12), having the length of said main leg tubular mullion structure (5M) minus the wall thickness of the lower cardboard (10), is applied and wherein the respective upper cardboard foil (2) is larger than the pallet and bent 180° on its surface to cover the respective hollows of the legs; the obtained tubular structured legs (5L) are connected in rows on their bottom one to the other in the same way with similar crown-hole-cut cardboard cross-pieces (15).

Inventors: DI CANDIDO VINCENZO, DI CANDIDO, VINCENZO
Applicants: NPI S R L, NPI S.R.L.
Application year: 1995
Main classification: B65D19
IPC codes: B65D19