EP0790189A1

EP0790189A1 - Box having integral corner posts

Info

Publication number: EP0790189A1
Application number: EP97300793A
Authority: EP
Inventors: Keith Winterborn
Original assignee: BPB Ltd
Current assignee: BPB Ltd
Priority date: 1996-02-13
Filing date: 1997-02-07
Publication date: 1997-08-20
Also published as: GB9602929D0; GB2310197B; GB2310197A

Abstract

A box formed from a cut and creased blank of foldable sheet board material, such as solid fibre board, has a corner construction allowing manual assembly, especially from a flat state. At each corner a side wall is hinged to a series of first (7), second (9) and third (11) hingedly connected panels. The first panel (7) is glued against the inside of the adjacent second side wall (5) which preferably has diagonal crease lines (104) extending from the corner so that the box can be shipped flat. On assembly, the side walls (3,5) are pulled upright, tabs (19,21) on the third panels (11) are engaged into slits in. the first side walls (3), and the second (9) and third panels (11) pushed into the corner until they lock with the third panel (11) extending diagonally across the corner.

Description

The present invention relates to a box or tray having reinforced corners, the box or tray being formed from a cut and creased blank of foldable sheet board material. The present invention also relates to a blank for the box or tray and a method of forming the box or tray from the blank.
A typically used box has a rectangular base, and first and second pairs of substantially parallel side walls upstanding from the base, and a reinforcing post at each corner of the box.
Such boxes or trays can be erected from blanks using tray-forming machinery which carries out the required folding and bending, and applies glue to fasten the box walls into place. British Patent Application No 9506287.3, as yet unpublished, discloses a box having a succession of hingedly connected panels at an edge of a side wall, the first of which panels lies against the interior of the adjoining side wall and a second of which extends diagonally across the corner as a reinforcement. The second reinforcement panel is held in position by a third panel which is fastened by glue or staples to the original side wall.
Dutch Patent Application No 9202028 discloses a box corner wherein the panel extending across the corner is divided into two equally sized panels. The fold line which divides these two panels is pushed into the corner and thereby allows the box to be collapsed and/or erected. As with the British patent application mentioned above, the panels extending across the corner are held in position by a further panel fastened by adhesive to the original side wall.
The present applicants have now appreciated that it is possible and desirable to provide a box having reinforced corners with good strength, and whose construction facilitates assembly by hand.
Accordingly, in a first aspect, the present invention provides a box formed from a cut and creased blank of a box formed from a cut and creased blank of foldable sheet board material, the box having a rectangular base and first and second pairs of substantially parallel side walls upstanding therefrom, the walls of each pair being hinged to opposite edges of the base, wherein at each corner of the box, an edge of a first side wall is hinged to a series of at least first, second and third hingedly connected panels;

said first panel lying against the interior of the adjoining second side panel;
said second panel having a width smaller than said first panel, returning part way towards the corner and lying face to face against part of said first panel;
said third panel extending from said second panel diagonally across the corner to the first side wall, said third panel being prolonged by one or more tabs engaged in slits in said first side wall, thereby engaging and holding the third panel in relation to the first side wall, with the said second panel held against said first panel.

In order to hold the second panel in place against the first panel which is itself lying against the second side wall, the third panel is desirably dimensioned to extend fully from the second panel to the first side wall, so that when the second panel is in place against the first panel, the third panel is fully engaged with the first side wall, even when the tabs are fully engaged into the slits in that side wall, and is not able to move closer to that wall.
The third panel may be slightly oversize, so that it bows slightly into the corner.
Such a construction allows for easy assembly of the box, because the third panel can be engaged with the first side wall before the second panel is pushed into place against the first panel.
We have found that such a construction provides very good compression strength at the corner.
Preferably the first panel is secured, e.g. glued to the second side wall before the box is assembled.
The invention is preferably applied in the context of a box in which the second pair of side walls have diagonal crease line extending inwardly and upwardly from their bottom corners. The first panels hinged to the first side wall are secured, e.g. by gluing, to the portions of the second side walls above the diagonal crease lines. The box can then be folded flat hinging at the diagonal crease lines, with the second and third panels lying against the interior of the second wall panels.
For use, the box can be erected by hand from this flattened condition, then the tabs on the third panels are engaged with the slits in the first side walls, and the second and third panels are pushed towards the box corners, locking the box in erect condition.
In a development of the present invention a further, fourth, hingedly connected panel is provided extending from the third panel. The one or more tabs which extend from the third panel are cut out from said fourth panel. In this way, once the tabs have been engaged, via slits, in the first side wall, the fourth panel can lie face-to-face against the side wall in a direction away from the corner. This fourth panel provides further compression strength at the corner and facilitates erection of the box.
It has been found that the second, third and fourth hingedly connected panels do not need to be glued or stapled: each panel acts to hold the others in place. It is, of course, possible to use adhesive to hold one panel against another and such a box is still within the scope of the present invention.
In a further preferred feature, at least one pair of side walls has marginal panels hinged to their upper edges and projecting inwardly above the base of the box.
It is convenient if the first side walls have marginal panels hinged to their upper edges, which project inwardly above the base of the box. These marginal panels are preferably prolonged at each end by flaps which are secured, e.g. with adhesive, to the second side walls. They may be glued in between the first panels and the second side walls.
The marginal panels on one pair of side walls may extend over end portions of the marginal panels on the other pair of side walls at the corners of the box, so that these end portions are sandwiched between the top of the corner-reinforcing panels and the marginal panels above them.
Marginal panels hinged to the second side walls may fold over and lie against the interior surface of the second side walls. The second side walls, or parts of them, may also be lower than the first side walls thereby allowing easy access to the contents of the box and to allow ventilation when the boxes or trays are stacked one on top of another.
In a second aspect, the present invention provides a cut and creased blank for a box as specified above.
Boxes and blanks according to the invention may be formed from various forms of foldable sheet. Preferred are solid fibre board and corrugated board. The boxes or trays may also incorporate ventilation holes either in the base or in the side walls. Likewise it may be desirable to incorporate hand-holes in the first side walls to enable the boxes to be picked up with ease.
In a third aspect, the present invention provides a method of folding a box according to the invention from a blank, by the steps of:

folding each first corner panel and securing it to the interior surface of the adjoining second side wall by gluing;
turning each second corner panel outwards from the second side wall;
engaging the tabs of the third corner panel with the slits in the first side wall, and pressing the second and third corner panels into the corner until the third panel extends diagonally across the corner and holds the second panel against said first panel.

The method may include further securing each marginal panel so as to project inwardly from the side panel to which it is hinged.
Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings in which:-

Fig 1 is an interior view of one corner of a box which is a first embodiment of the invention;
Fig 2 shows the blank for the box of Fig 1;
Fig 3 is a horizontal cross-section of a corner of the box of Fig 1;
Fig 4 is an interior view of one corner of a second box;
Fig 5 shows the blank for the box of Fig 4; and
Fig 6 is a horizontal cross-section of a corner of the box of Fig 4.

The box of Fig 1 is made from a cut and creased blank of solid fibreboard, seen in Fig 2.
As shown in Figs 1 and 2, a box has a rectangular base 1 and first and second pairs of rectangular side walls 3 and 5 hinged to the base 1 along crease lines 101 and 103 respectively. Each of the second side walls 5 includes generally triangular flaps 6 hinged to the trapezoidal middle part of the wall along crease lines 104 which extend diagonally from corners of the box. Adjacent side walls 3,5 meet at the box corners, each of which is reinforced by three corner panels 7,9,11. The first corner panel 7 is connected to the edge of a first side wall 3 along a crease line 105. When the box is erect this first corner panel 7 extends substantially at right angles from the side wall 3 to lie against the interior of the adjacent second side wall 5. The first panel 7 is fixed, e.g. glued or stapled, to the flap 6 of the second side wall 5. The second corner panel 9 is hinged to the first panel 7 along crease line 107 and extends back towards the corner so as to lie face-to-face against part of the first corner panel 7. The third corner panel 11 is hinged to the second corner panel 9 along crease line 109 and extends across the corner to the side wall 3. The third corner panel 11 has two tabs 19,21 extending from its distal edge 23. These two tabs 19,21 engage with corresponding slits 25,28 respectively, in the first side wall 3.
The particular dimensions of the corner panels in relation to each other ensure that the third panel 11 holds the second corner panel 9 firmly against the first corner panel 7 without the use of any adhesive, even when tabs 19,21 are thrust fully into slits 25,28. The entire corner arrangement provides for a box corner having a strong compression strength as well as being simple to hand erect.
Marginal panels 27 are hinged to the side walls 3 along crease lines 111 which are parallel to crease lines 101 and, similarly, marginal panels 29 are hinged to the side panels 5 along crease lines 113 parallel to crease lines 103. The marginal panels 27 hingedly connected to the first side walls 3 have flaps 33 (shown in Fig. 2) at their ends which, when the box is erected are sandwiched between the first corner panel 7 and the adjacent flap 6 of second side wall 5.
The marginal panel 29, hingedly connected to the second side wall 7 along crease line 113, is folded completely over and lies against the interior surface of the second side wall 7.
After cutting and creasing the blank, the box is fabricated in a collapsed state. The walls 5 are turned down over the base 1, with the flaps 6 folded over. The corner panels are turned inwardly against the inside of walls 3, and the flaps 33 are turned downwards by folding on lines 114. The walls 3 are folding inwardly over the base 1, which brings the first corner panels 7 onto the flaps 6, with flaps 33 inbetween. Adhesive is applied prior to folding so that the corner panels 11 are secured to flaps 6. In this collapsed state the panels 9,11 remain approximately coplanar with first corner panels 7.
When required for use the walls 3,5 are raised again and the tabs 19,21 of each third corner panel 11 are engaged with the slits 25,28 while the second panel 9 projects inwardly as shown in phantom in Fig 3. This is easily done with little force.
Panels 9,11 are then pushed into the corner e.g. by force along arrow F, causing the panels to snap to their final position as seen in Fig 1, and full lines in Fig 3.
Fig 4 shows a corner of a second embodiment of the invention. Fig 5 shows the blank of this box. Fig 6 shows a cross-section of the box corner. The same reference numbers are used in Figs 1 to 3, so far as appropriate.
Referring firstly to Fig 4, the box corner is substantially similar to that of the first embodiment except for a further, fourth corner panel 41. This fourth corner panel 41 is hinged to the third corner panel 11 along crease line 115. The two tabs 21, 19 extending from the third corner panel 11 are cut out from the fourth corner panel 41. The fourth panel 41 is convenient as a 'handle' to push the panel 11 into place with its tabs 19,21 engaging slits 25,28. When these two tabs engage with the slits 25, 28 in the first side wall 3, the fourth corner panel 41 lies flat against the interior surface of the first side wall 3.
Referring to Fig 6, the flap 6 of second side wall 5 is glued to the flap 33 extending from the edge of the marginal panel 27 hinged to the first side wall 3. The tab 33 is likewise glued to the first corner panel 7, so that the panel 7 is secured to flap 6 with flap 33 sandwiched in between.
The second corner panel 9 is held firmly against the first corner panel 7 by the third corner panel 11 just as occurs in the embodiment of Figs 1 to 3. The third corner panel 11 engages the first side wall 3 with tabs 19,21 and is dimensioned to hold the second panel 9 in place, while the tabs 19,21 are inserted to the fullest extent into slits 25,28. Depending on the stiffness of the foldable sheet used, the third panel may then bow inwardly to the position shown at 11' which keeps the tabs 19,21 thrust into the slits 25,28.
It is not essential that flaps 33 are sandwiched between panels 7 and flaps 6. The flaps 33 could be secured to the inside faces of panels 7. They could also be secured against the outside of walls 5, after erection of the box.

Claims

A box formed from a cut and creased blank of foldable sheet board material, the box having a rectangular base and first and second pairs of substantially parallel side walls upstanding therefrom, the walls of each pair being hinged to opposite edges of the base, wherein at each corner of the box, an edge of a first side wall is hinged to a series of at least first (7), second (9) and third (11) hingedly connected panels;
said first panel (7) lying against the interior of the adjoining second side panel;

said second panel (9) having a width smaller than said first panel (7), returning part way towards the corner and lying face to face against part of said first panel;

said third panel (11) extending from said second panel diagonally across the corner to the first side wall (3), said third panel being prolonged by one or more tabs (19,21) engaged in slits (25,28) in said first side wall, thereby engaging and holding the third panel in relation to the first side wall (3), with the said second panel held against said first panel.
A box according to claim 1 or claim 2 wherein the third panel (11) extends fully from said second panel (9) to the first side wall (3), the third panel (11) being fully engaged with said first side wall (3) such that said second panel (9) is held securely against said second side wall (5).
A box according to claim 2 wherein the third panel (11) is oversized such that it bows towards the corner.
A box according to any one of the preceding claims wherein the second pair of side walls (5) have diagonal crease lines (104) extending inwardly and upwardly from their bottom corners, the first panels (7), hinged to the first side walls (3), being secured to the second side walls (5) above the diagonal crease lines (104).
A box according to any one of the preceding claims further comprising a fourth hingedly connected panel extending from the third panel.
A box according to claim 5 wherein the one or more tabs extending from the third panel are cut out from said fourth panel and said fourth panel lies face to face against the interior of said first side wall in the direction away from the corner.
A box according to any one of the preceding claims further comprising marginal panels (27) hinged to the upper edges (101) of said first side walls (3) and projecting inwardly above the base of the box.
A cut and creased blank of foldable sheet board material, for a box according to any one of the preceding claims, which blank has a rectangular base (1) and first (3) and second (5) pairs of side walls hinged to opposite edges of the base (1), wherein at each corner an edge of a first side wall (3) is hinged to a series of first, second and third hingedly connected panels, said second panel (9) having a width smaller than the width of said first panel (7), said third panel (11) being prolonged by one or more tabs engageable in slits in said first side wall.
A method of folding a box according to the invention from a blank according to claim 8, by the steps of:
folding each first panel (3) and securing it to the interior surface of the adjoining second side wall (5) by gluing;

turning each second panel (9) outwards from the adjacent second side wall;

engaging the tab or tabs (19,21) on each third panel (11) with the slit or slits (25,28) in the adjacent first side wall (3), and pressing the second and third panels into the corner until the third panel extends diagonally across the corner and holds the second panel against the first panel.
A method according to claim 9 further having the step of securing each marginal panel (27) so as to project inwardly from the side panel to which it is hinged.