The present invention refers to a cardboard box, of the type used for example for the transportation of fruit, and particularly of the type formed by a single sheet that conveniently shaped constitutes a cuboid container open at the top.
The object of the invention is to obtain a box simple in structure, easy to assemble and resistant enough to be piled up.
Some carboard boxes are known of the type formed by a single sheet with a bottom panel which is separated by folding lines to the side walls and by folding lines to double front end walls, each of the double front end walls consisting of two parts, an initial section and an end section joined by a double folding line, so that the end section is folded onto the inner side of the initial section.
The US-A-5125568 patent refers to a stacking tray formed by double side walls, not with double front end walls, and the side prolongations of this double side walls are bended orthogonally with respect to the double side wall, requiring a U-shaped bracket to secure the fix these side prolongations. Two tab elements are extending from the upper edge of each side wall prolongations that are needed to be joined by said racket for mounting the box, and these tabs are used for fitting in a central opening of an upper box which is piled up.
The US 5125568 patent shows a tray with a double side wall, and its central part is extended on the bottom panel reducing the capacity of the box and damaging the fruits by friction of the edge of the extending portion.
In the US 5125568 patent there is not a continuous surface and the box needs the U shaped bracket, being so easily for the box be disassembled when the bracket escape from its fixed position by manipulating.
To overcome these problems we claim a carboard box that doesn't need this kind of fixing means like in the US patent, and that have means to contribute to a better way of piling up.
The invention is characterized by the features of claim 1.
For these purposes, there is a central section in the single sheet of the cardboard box, forming to the bottom, that extends longitudinally along the folding lines in the two front end walls and the two side walls of the box. These front end walls are double, so that the end section is designated to be folded onto the inner side of the initial section, and have side prolongations in both sections, forming two sections joined by a double folding line that also joins the two sections of the double front end walls.
The initial section of each prolongation of each double front end walls is joined to the initial section of the double front end wall by a folding line, corresponding to the vertical edge of the box, while the end section is joined to the end section of the double front end wall by three folding lines, one folding line situated inwards with respect to the previous folding line, and the other two folding lines placed slightly outwards. The section of the double folding line comprised between these two folding lines is transformed into a cut line that allows to form a V column with the area defined between them, as we will see in detail further on.
According to this special structure, the two sections of each side prolongation of each double front end wall are designed to cover the interior and the exterior part of both ends of the large side, so that in this zone there is a triple wall, that together with the double wall of the double front end wall constitutes a great structural rigidity, and the columns formed coinciding with the vertical edges of the box allow to pile them up securing a perfect stability.
In order to complete this description and to help to understand better the characteristics of the invention, there is a set of drawings attached to this document that represent with illustrative and not limitative character:
In these figures, and particularly in Figure 1, it can be observed that the cardboard box proposed by the invention is formed by a single sheet, with a central section (1) forming the bottom of the rectangular box, delineated by folding lines (2, 2') that join the bottom (1) with the side walls of the box (3), folding lines (2) where there are circular holes for ventilation (4) that perforate both the bottom and the side wall (3); these side walls have typically shaped notches (5) cut out of the middle of the upper edge that contribute to the ventilation of the interior of the box.
Other two folding lines (6, 6') join the central section (1) with the front end walls (7) which are double, an initial section (7) and an end section (8) joined to the first one by a double break line (9), through which the end section folds onto the inner side of the initial section, both sections having windows (10) that coincide when folded and constitute the handles of the box.
Each double front end wall (7-8) has end or lateral prolongations which at the same time have two sections (11) and (12) corresponding to sections (7) and (8) mentioned before, and joined by a prolongation (9') of the double folding line (9). The initial section (11) is joined to the section (7) of the double front end wall by a single folding line (13) that corresponds to the vertical edge of the box once assembled, while the end section (12) is joined to the end section (8) of the wall by three folding lines, one inner folding line (14) that is situated inwards with respect to the break line (13) of the initial section, and other two folding lines (15, 15') that form a small fold (16), the exterior part of the double line (9, 9') mentioned before that joins the folding lines (14) and (15) transformed into a cut line (17) that allows to form, as shown in Figures 2 and 3, a flap (18) defined between both lines (14, 15), a slantwise wall that constitutes an V column for the rigidization of the vertical edges of the box.
As a complement of the structure described, there is an opening (19) in each corner of the bottom (1) of the box, which has a triangular shape in this example of realization, but could also be square or rectangular, and designed to introduce a small angular flange (20) defined by the cut line (17) mentioned before and other two transverse cut lines (21, 21') situated between the double folding lines (9, 9') as a prolongation of folding lines (14) and (15) that delimit the area (18) of the end section of the walls.
According to this structure, as explained before and shown in detail in Figures 2 and 3, the end section (8) of the wall is folded onto the initial section (7) of the wall, folding at the same time the end section (12) of the side prolongations of the double front end walls onto the initial section (11) of these prolongations, which bend orthogonally onto the folding line (13) and bluntly onto the break line (14), forming a fold (16) and joining the sections (11) and (12) of the prolongations of the double front end walls to the corresponding end section of the side walls (3), fixing them with adhesive, although they can also be fixed with staples, forming with the fold (16) an area (18), a slantwise wall that constitutes a triangular column for the rigidization of the box, having an opening (19) at the bottom that fits into the angular flange (20) of the box situated underneath, which protrudes with respect to the upper part of the box, as shown in Figure 3.
It is not considered necessary to make any further explanation for any expert in the matter to understand the significance and advantages of the invention.