FR2782031A1 - PROCESS FOR REINFORCING THE CARRIER WALLS OF A CORRUGATED CARTON PACKAGING AND PACKAGING OBTAINED BY THIS PROCESS - Google Patents

Abstract

The invention relates to a method for reinforcing the load-bearing walls of a packaging produced from a corrugated cardboard blank, in which each of the load-bearing walls is constituted by a flap (24) articulated on the bottom wall (22) of the conditioning by a fold line (26). The method consists in making on the inside face of the flap (24), substantially at an equal distance between its free edge (27) and said fold line, a straight cut to half-flesh ( 28) which defines on the flap a side wall (30) and a flap (32); erecting the flap (24) perpendicular to the bottom wall (22); folding the flap (32) towards the outside of the packaging and sticking it on the outside of the side wall.

Description

i Method for strengthening the load-bearing walls of a packaging

corrugated cardboard and packaging

obtained by this process.

FIELD OF THE INVENTION

  The present invention relates to a method of strengthening the stacking resistance of the load-bearing walls of a corrugated cardboard packaging and a

  conditioning obtained by this process.

PRIOR STATE OF THE ART

  It is known to reinforce the resistance to stacking of the load-bearing walls of a corrugated cardboard packaging by folding or flipping inwards the packaging of the flaps which are articulated on the upper edge of the load-bearing walls by double delivery lines. These flaps which have a width substantially equal to the height of the walls, are applied to the inner wall of the latter and their lower free edge is wedged against the bottom wall of the packaging. The thickness of the walls is thus

doubled over the entire height.

  To give maximum compressive strength to the transverse walls, the corrugated cardboard grooves must be oriented vertically in the side walls and in the flaps and therefore the double discharge lines must be oriented in a direction perpendicular to the grooves. cardboard. These double delivery lines are produced by marking two very close parallel folding lines on the cardboard blank from which the packaging originates. In packaging in the assembled state, the narrow strip defined between the two fold lines is in principle rectilinear

  and contained in a horizontal plane.

  However, experience shows that, most of the time, this strip has an irregular profile, due to the fact that it is difficult to control the crushing of the corrugated cardboard grooves on the delivery lines. It is found that this strip is often curled or that it has a certain degree of warping. It follows that when several packages are stacked, the compressive force may only be exerted on certain discrete points of the upper edge of the side walls. At these points, the side walls may buckle or have a certain

  fatigue which reduces its resistance to stacking.

  Another disadvantage of the inward folding of the side walls lies in the fact that the contact between the lower edge of the flaps and the bottom wall is relatively elastic due to the presence in the bottom wall of the cardboard grooves. Thus, during stacking, the side walls may undergo a slight deformation due to the crushing of the grooves in the bottom wall.

SUMMARY OF THE INVENTION

  The present invention aims to remedy these drawbacks and firstly proposes a method for reinforcing the load-bearing walls of a package produced from a corrugated cardboard blank with at least one corrugated layer, in which each of the load-bearing walls is made up by a flap articulated on the bottom wall of the packaging by a fold line, said method being characterized in that it consists: in making on said flap, substantially at equal distance between its free edge and said fold line, a cut rectilinear to half-flesh which cuts the entire thickness of the cardboard except the cover sheet located on the outer face of the blank, said cut defining on either side, a lateral wall articulated on the bottom wall by said line of folding and a flap hinged to said side wall by a connecting line formed on the blank sheet; erecting the flap perpendicular to the bottom wall; folding the flap towards the outside of the packaging by pivoting it around said connecting line; and gluing the flap to the outside of the side wall. There is thus obtained at the top of the side wall and the adjoining flap a perfectly flat and horizontal support surface, of width equal to twice the thickness of the carton. This surface provides stable and regular support for

another conditioning.

  The flap has a height exactly equal to that of the side wall, so that its lower edge reaches the same level as the underside of the bottom wall. It follows that when several packages are stacked, the side wall and the flap of each of them rest on the side wall and the flap of the

underlying packaging.

  The compression force is therefore equally distributed between the side wall and the flap and is exerted uniformly on

the entire length of these.

  The invention also relates to a packaging obtained

by the method described above.

  DESCRIPTION OF A PREFERRED EMBODIMENT

  An embodiment of the invention will now be described with reference to the accompanying drawing in which: FIG. 1 shows a partial view of a corrugated cardboard blank showing in particular a side wall and its flap with a half-cut section between them; Figure 2 is an enlarged sectional view along line II-II of Figure 1; Figure 3 is a partial sectional view illustrating the method of folding the blank to form the side wall folded outwardly by the flap; FIG. 4 represents a particular embodiment of a blank used to produce a packaging provided with load-bearing side walls reinforced by the method illustrated in FIGS. 1 to 3; and Figure 5 shows the packaging carried out with the

blank of figure 4.

  DETAILED DESCRIPTION OF AN EMBODIMENT

  We will first explain the principle of the reinforcement method according to the invention with reference to Figures 1 to 3 which show a portion of blank in corrugated cardboard comprising two fluted layers 10, 12 separated by a sheet of intermediate paper 14 and covered externally by two inner 16 and outer 18 covering sheets, but as will be seen, the invention also applies to a corrugated cardboard comprising one, two

or more fluted layers.

  The blank portion 20 comprises a bottom wall 22 on which a flap 24 is articulated by a fold line 26. The fold line is formed on the face of the blank intended to be inside the packaging, and which is the visible side in FIG. 1. The shutter has a width L which is twice the height h of the box that we want to make. About halfway between the fold line

  26 and the edge 27 of the flap 24, a mid-cut is made

  flesh 28 which cuts the cardboard over its entire thickness with the exception of the outer cover sheet 18. The cut 28 defines on the shutter a side wall 30 articulated to the bottom wall 22 by the fold line 26 and a flap 32 which is attached to the side wall only by the line 34 not cut from the cover sheet

exterior 18.

  The fold line 26 and the cut 28 are

  perpendicular to the direction of the grooves 35.

  FIG. 3 shows the method of folding the blank: the flap 24 is raised to bring it into position perpendicular to the bottom wall 22, by folding around the fold line 26, then the flap 32 is folded outwards around the connecting line 34. The flap is then glued to the face

exterior of the side wall.

  Because the cut 28 is rectilinear, there is obtained at the upper part of the side wall and of the flap a very regular cut surface 36, flat and horizontal over its entire length. In addition, the lower edge 27 of the flap is located exactly at the same level as that of the lower face 40 of the bottom wall. It follows from these two characteristics that if several packages are stacked, the compression force is distributed equally on the side wall and the flap of each package and uniformly over the entire length of these elements. The packaging therefore has a compressive strength much higher than that of internally wrapped packaging. We will now describe in detail with reference to Figures 4 and 5, an example of packaging, here a tray for

Brie cheese.

  Figure 4 shows the blank 50 from which the tray is made. This blank is substantially rectangular and comprises a central bottom wall 52 of square or rectangular shape, two longitudinal walls 54, 56 articulated by fold lines 58, 60 along two parallel sides of the bottom wall and two flaps 62, 64 articulated by fold lines 66, 68 along the other two sides of the bottom wall. The flaps 62, 64 have a width greater than or equal to twice that of the walls

longitudinal 54, 56.

  Four rectilinear slots 70, 72 and 74, 76 are formed from the two longitudinal edges of the blank, in alignment with the fold lines 66, 68 and over a distance d substantially equal to twice the width 1 of the walls

longitudinal.

  The flaps 62, 64 are shared by mid-sections

  flesh 78, 80, in strips 82, 84 and 86, 88 of equal width 1.

  The blank having a central symmetry, we will only describe

the left side.

  The bands 82, 84 are separated at their ends by incisions 90, 92, of the same length as the slots 70, 72. Thus, at the ends of the bands, independent legs 94, 96 and 98, 100 are defined. The inner legs 94 98, that is to say those associated with the inner strip 82, can be folded along fold lines 102, 104 passing through the ends of the slots 70,

72.

  On the outer legs 96, 100 are marked fold lines 106, 108 aligned with the longitudinal fold lines 58, 60. These fold lines define, at the ends of the legs, external fixing tabs

110, 112.

  On the inner legs 94, 98 are marked fold lines 114, 116 parallel to the fold lines 102, 104 and which define, on both sides, corner elements 118, 120 and fixing tabs

internal 122, 124.

  U-shaped incisions are made on the outer strip 84, from the half-cut section 78, so as to release centering pins 126, 128. Recesses 130, 132 of shape complementary to that of the pins are drilled in the inner strip 82, along the transverse fold line 66. These recesses are intended to receive the pins of a lower packaging. The shaping of the packaging tray is done as follows: we start by erecting the flaps 62, 64 perpendicular to the bottom wall 52 by folding around the fold lines 66, 68, then folding the outer strips 84, 88 outwards, by folding around the half-cuts 78, 80 to apply them against the outside face of the interior strips 82, 86. The strips

  outside are glued on the inside strips.

  The inner tabs 94, 98 are then folded inwards around the fold lines 102, 114; 104, 116, then the longitudinal walls 54, 56 are erected perpendicular to the bottom wall 52 by folding around

fold lines 58, 60.

  Then glue the inner tabs 122, 124 to the inner face of the longitudinal walls 54, 56, taking care that the corner elements 118, 120 are placed diagonally in the corners of the bottom wall 52. Finally, the outer tabs 110, 112 and they are glued to the outer face of the longitudinal walls 54, 56. The plate shown in FIG. 5 is then obtained. This plate is particularly resistant because it has two transverse load-bearing walls each formed of two thicknesses of cardboard and also because the ends of the longitudinal walls are sandwiched between the

  interior tabs and exterior tabs.

Claims (6)

  1. Method for reinforcing the load-bearing walls of a packaging produced from a blank (20) of corrugated cardboard with at least one fluted layer (10, 12), in which each of the load-bearing walls is constituted by a flap (24 ) articulated on the bottom wall (22) of the packaging by a fold line (26), said method being characterized in that it consists: in practicing on the inside face of the flap (24), substantially at equal distance between its free edge (27) and said fold line, a rectilinear half-flesh cut (28) which cuts the entire thickness of the carton except the cover sheet (18) located on the outside face of the blank, said cut defining on either side, a side wall (30) articulated on the bottom wall (22) by said fold line (26) and a flap (32) articulated on the side wall by a connecting line (34) formed on said outer cover sheet (18); erecting the flap (24) perpendicular to the bottom wall (22); folding the flap (32) towards the outside of the packaging by pivoting it around said connecting line (34); and stick the flap on the outside of the wall lateral.   2. Packaging produced from a corrugated cardboard blank (20) with at least one grooved layer (10, 12) and comprising a bottom wall (22) and at least one flap (24) articulated on the bottom wall by a fold line (26), characterized in that said flap (24) comprises, on the inner face, substantially at equal distance between its free edge (27) and the fold line (26), a rectilinear section at mid -chair (28) which cuts the entire thickness of the cardboard except the cover sheet (18) located on the face outside of the blank.   3. Packaging according to claim 2, characterized in that the lower edge (17) of the flap arrives at the same   level than the underside (40) of the bottom wall.   4. Packaging according to claim 2, made with corrugated cardboard which comprises one or more fluted layers (10, 12) connected together by at least one sheet of intermediate paper (14) and covered on their outer faces by cover sheets (16, 18), characterized in that the half-cut is made through the inner cover sheet (16), the fluted layer (s) (10, 12) and the intermediate sheet (s), but not on the cover sheet exterior (18).   5. Packaging according to one of claims 2 to 4,   characterized in that it comprises a bottom wall (52) and two longitudinal side walls (54, 56) and two transverse side walls (82, 86), articulated on the bottom wall by fold lines (58, 60 , 66, 68), each of said transverse side walls (82, 86) being doubled by a flap (84) which is articulated on the latter by a half-cut (78), said transverse wall (82) and said flap (84) being provided at their ends with tongues (122, 124 and 110, 112) foldable along fold lines (114, 116) perpendicular to the fold line (66) of said transverse wall (82) on the bottom wall (52), the tongues (122, 124) which are contiguous to said transverse wall (82) being glued to the inside of two longitudinal side walls (54, 56) adjacent to said transverse wall (82), while that the tabs (110, 112) which are adjacent to the flap (84) are glued to the outer face of said p longitudinal arois (54, 56).   6. Packaging according to claim 5, characterized in that said transverse wall (82) is extended by interior corner elements (118, 120) which are placed diagonally in the corners of the packaging defined between said side wall and said longitudinal walls (54, 56), said corner elements in turn being extended by tongues (122, 124) which are glued to the face   interior of said longitudinal walls (54, 56).