Collapsible box with corner reinforcements

Abstract

 A box precursor which is generally flat, having preformed fold lines to allow it to be opened out to form a box. The box precursor has corner elements (8) which expand for form corner posts when the box precursor is opened out to form the box. The box precursor also having resistance elements (26) which on opening out of the box precursor provides resistance against the box collapsing towards its box precursor form.

Description

[0001] This invention relates to a box.

[0002] In the meat and vegetable trades it is important for boxes to have inherent strength and to be stackable for storage and transportation of the contents. These features are provided by the boxes having strengthened corners, often in the form of corner posts formed by folding and gluing the sheet material of which the box is made. However, it is also important that the boxes should be transported and stored flat prior to their use, in order to save space, and as a result it has often been necessary for meat and vegetable packers to install gluing machines at their premises so that the flat blanks provided from the packaging manufacturer can be folded and glued into final shape on site.

[0003] The alternative is for boxes to be provided to the packer already glued, and simply folded flat; attempts have been made in this direction, but these have not generally been commercially successful, and have involved significant time in assembly.

[0004] According to the present invention there is provided a box precursor openable between a generally flat shape and a box defining shape, the box precursor having elements expandable between the flat shape and the box defining shape to form corner posts, the box precursor including a resistance element which in the box defining shape provides resistance against the box collapsing towards the flat shape.

[0005] Preferably, the precursor has pre-formed fold lines allowing it to be opened out from the generally flat shape to form the box defining shape.

[0006] Preferably, the elements are corner elements secured or integral with the box precursor.

[0007] Preferably, the resistance element is a free end portion extendable along a top edge of a wall of the box, allowing the free end portion to be folded about the top edge to create an over-centre effect to lock the box in its opened-out position.

[0008] Preferably, the free end portion is connected to the top edge of the wall of the box along a pre-formed fold line.

[0009] Preferably, a second resistance element is provided on a second wall of the box.

[0010] Preferably, the resistance elements and corner elements are integral with the box precursor.

[0011] Preferably, the corner posts are polygonal in cross-section.

[0012] According to a further aspect of the present invention there is provided a blank for forming a box precursor as claimed in any preceding claim, comprising a bottom panel and a pair of first and second side wall panels connected to the bottom panel, the blank being provided with elements for forming corner posts in a box formed from the box precursor, at least one of the side wall panels being provided with a resistance element to resist collapse of the box.

[0013] Preferably, the bottom panel and the first and second side wall panels are connected along first and second bottom panel fold lines, the second side wall panels being provided with corner elements connected with opposite ends of the second side wall panels along corner edge fold lines, each corner element having at least one fold line adapted to facilitate folding of the corner elements into the corner posts.

[0014] Preferably, the resistance element is connected with a top edge of the second side wall panel, along a free end fold line the second side wall panel and the resistance element being further provided with second side wall panel fold lines extending at an angle of approximately 45° from opposite bottom end corner points of the second side wall panel to a free edge of the resistance element.

[0015] Preferably, the resistance element comprises resistance fold lines extending at an angle of approximately 45° from corner points thereof adjacent the second side wall panel, and a securing tab element to secure the corner posts connected to opposite ends of the resistance element along tab fold lines.

[0016] Preferably, each of the second side wall panels is provided with a resistance element.

[0017] In a further aspect of the present invention, there is provided a method for forming a box precursor comprising forming a blank comprising a bottom panel and a pair of first and second side wall panels connected to the bottom panel, the blank being provided with elements for forming corner posts in a box formed from the box precursor, at least one of the side wall panels being provided with a resistance element to resist collapse of the box and folding the blank.

[0018] Preferably, the method for forming the box precursor comprises the steps of, folding outer portions of the corner elements of each second side wall panel in an inwardly direction about the second corner fold lines, placing adhesive on portions of the second side wall panels adjacent the corner edge fold lines and intermediate the side second side wall panel fold lines and free end fold lines, further folding the corner elements about corner edge fold lines so that a face of the outermost portion of each of the corner elements lie against the adhesive portions thus securing the outermost portions against an end portion of the second side wall panels, applying adhesive to a free face of innermost portions of the corner elements and folding securing tab elements about the resistance fold lines to lie against and be secured to the innermost portions of the corner elements, folding the second side wall panels inwardly about the second bottom panel fold lines and outwardly about second side panel fold lines so that the second side wall panels, the corner post elements and a free face of the tab elements lie flat on the bottom panel, further applying adhesive to the free face of the tab elements and folding the first side wall panels inwardly about first bottom panel fold lines so that end portions of the first side wall panels lie against and are secured to the tab elements.

[0019] Alternatively, and according to a further aspect of the present invention the method for forming the box precursor comprises the steps of, folding outer portions of the corner elements of each second side wall panel in an inwardly direction about the second corner fold lines , placing adhesive on portions of the second side wall panels adjacent the corner edge fold lines and intermediate the side second side wall panel fold lines and free end fold lines, further folding the corner elements about corner edge fold lines so that a face of the outermost portion of each of the corner elements lie against the adhesive portions thus securing the outermost portions against an end portion of the second side wall panels, applying adhesive to a free face of innermost portions of the corner elements and folding securing tab elements about the resistance fold lines to lie against and be secured to the innermost portions of the corner elements, folding the second side wall panels inwardly about the second bottom panel fold lines and outwardly about second side panel fold lines so that the second side wall panels, the corner post elements and a free face of the tab elements lie flat on the bottom panel, further applying adhesive to the free face of the tab elements and folding the first side wall panels inwardly about first bottom panel fold lines so that end portions of the first side wall panels lie against and are secured to the tab elements.

[0020] Further according to the invention there is provided a box produced by opening out a precursor of the invention.

[0021] The box of the present invention can be transported in its flat precursor form allowing for an easier stacking arrangement which can accommodate a greater number of boxes. As the box precursor is already glued, the packer can simply form the box by opening out the walls. This simple action of opening out the walls forms the corner posts and folds the free end portion about the top edges of opposite walls of the box creating an over-centre effect in each of the walls thus preventing the box from collapsing back into a flat shape.

[0022] An embodiment of this invention will now be described by way of example only with reference to the accompanying diagrammatic drawings, in which:

Fig. 1 is a plan view of a blank for forming a box precursor according to a first embodiment of the present invention;

Fig. 2(a) is a plan view of the blank of Fig. 1 partly made up into the box precursor showing corner elements at different stages of construction;

Fig. 2(b) is a plan view of Fig. 2a at a later stage in the construction of the box precursor;

Fig. 3 is a plan view of a box precursor made from the blank of Fig. 1;

Fig. 4 is a plan view of a box made from the precursor of Fig. 3;

Fig. 5 is a plan view of a blank for forming a box precursor according to a second embodiment of the present invention;

Fig. 6(a) is a plan view of the blank of Fig. 5 partly made up into the box precursor showing corner elements at different stages of construction;

Fig. 6(b) is a plan view of Fig. 6(a) at a later stage in the construction of the box precursor;

Fig. 7 is a plan view of a box precursor made from the blank of Fig. 5; and

Fig. 8 is a plan view of a box made from the precursor of Fig. 7.

[0023] Referring now to the drawings and initially to Fig. 1, there is shown a blank indicated generally by the reference numeral 1, in the form of a substantially rectangular sheet of solidboard having elements providing the basis for a box, namely a floor 2, side walls 4, end walls 6 and corner elements 8. The blank 1 has a number of fold lines, described further below, in the form of weakened or scored lines, each shown in Fig. 1 as a broken line. The blank 1 can be folded into the form of a box or a box precursor along the fold lines. Top and underside portions of the blank 1 are adapted to receive hot melt glue to assemble the blank 1 into a box. The top and underside hot melt glue receiving portions are indicated by hatched and cross-hatched portions respectively.

[0024] The end walls 6 and side walls 4 are connected to the floor 2 along first and second floor fold lines 23 and 24 respectively. The corner elements 8 are connected to opposite ends of the end wall 6 along corner edge fold lines 13. Each corner element 8 has first, second and third corner fold lines 9, 10 and 11 repectively which are parallel to the corner edge fold lines 13 and which divide the corner elements 8 into four substantially equal portions. A resistance element in the form of a free end portion 26 is connected with a top edge of each end wall 6 along a free end fold line 28 remote from the floor 2. The end walls 6 have a pair of end wall fold lines 22 which extend at an angle of approximately 45° from opposite bottom end corner points of the end wall 6 to a free edge of the free end portion 26. The free end portion 26 has resistance fold lines 18 extending at an angle of approximately 45 from corner points thereof adjacent the end wall 6. The blank 1 further has securing tab 16 connected to opposite ends of the free end portion 26 along tab fold lines 27.

[0025] The blank of Fig. 1 is transformed into a precursor box of Fig. 3 as follows: an outer portion 8a of each of the four corner post elements 8 is folded inwards about second corner fold line 10 to lie flat against an inner portion 8b. Hot melt glue is then applied to a top portion 12 of the blank 1 adjacent the corner edge fold line 13 and intermediate the end wall fold line 22 and free end fold line 28. The folded corner post element 8 is then folded inwards about corner edge fold line 13 so that an underside face of an outermost portion 8aa of the corner post element 8 lies against the portion 12, thus securing the outermost portion 8aa against an end portion of the end wall 6. Hot melt glue is then applied to an underside face 8bb of an innermost portion of the corner post element 8 and the tab element 16 of the blank is folded about resistance fold line 18 to lie against the glued face 8bb, securing the tab element 16 against it.

[0026] Hot melt glue is then applied to the other face of the tab element 16, and the end wall 6 is folded outwardly about the end wall fold lines 22 and inwardly about first floor fold line 23 so that the face of the tab element 16, and the corner post elements 8 lie flat on the floor 2. The side wall 4 is then folded inwardly about the second floor fold line 24 until its end portion lies against the tab element 16 and is secured thereto by the hot melt glue.

[0027] Both ends of each side of the blank are treated simultaneously as described above, resulting in the box precursor shown in Fig. 3. The precursor is essentially flat, although multiply at the corners and along each end and side.

[0028] To produce the box shown in Fig. 4, the side walls 4 are raised about the second floor fold lines 24 until they extend upwardly at right angles from the floor 2. This action pulls the end walls 6 upwardly about the second floor fold lines 23, simultaneously causing the end walls 6 to open out by hinging about the end wall fold lines 22.

[0029] In that position the end walls 6 are still partly folded inwardly about the first floor fold lines 23, and the corner post elements 8 have been pulled from their flat, stacked attitude into a rhombic cross-sectional shape.

[0030] From there the free end portion 26 of the end wall elements 6 are folded inwardly about free end fold lines 28 and this causes the end walls 6 to be pulled fully up until they extend at right angles from the floor 2; this in turn pulls the corner post elements 8 into a square cross-sectional shape. The folding is completed when the tab elements 16 fold about tab end fold lines 27 so that the tab elements 16 lie at an angle of approximately 90° to the free end portions 26, and the free end portions 26 extend parallel to the floor element 2 which produces an over-centre effect in locking the box structure in place as shown in Fig. 4.

[0031] The over-centre effect takes the form of a slight bulge in an outwardly direction at a mid portion of each end wall 6.

[0032] It will be appreciated that the blank of Fig. 1 may have a surface protective coating, for example, a PE-coating. This is desirable especially for cardboard boxes which may otherwise be weakened by, for example, air humidity or fluid leakages from the contents of the box. When the box with the PE-coating is assembled, the PE-coating should preferably be on the interior of the box. Ideally, the PE-coating should also be on the exterior walls of the corner post elements 8 when the box is assembled.

[0033] Fig. 5 shows a plan view of a second embodiment of a blank 1 in accordance with the invention adapted to fold to provide corner post elements having a PE coating on their exterior walls. The blank 1 of Fig. 5 is broadly similar to the embodiment of Fig. 1 save that the fold lines and the hot melt glue receiving portions are located and oriented on the blank 1 to facilitate a alternative assembly method. Accordingly, like numerals indicate like parts. As indicated above, the sequence of folding and the application of hot melt glue is different to that previously described. However, in a similar fashion to the first embodiment, top and underside portions of the blank of Fig. 5 are designated to receive hot melt glue, and these are indicated by the hatched and cross-hatched portions respectively. The different stages of folding of the blank 1 of the second embodiment and the application of the hot melt glue are clearly shown in Figs. 5 to 8.

[0034] In the present embodiment, hot melt glue is first applied to the top portions 12 of the blank 1. The corner post element 8 is then folded inwards about the corner edge fold line 13 so that a face of the innermost portion 8bb of the corner post element 8 lies against the top portion 12, thus securing the innermost portion 8bb against an end portion of the end wall 6. The corner element 8 is then further folded in an outwardly direction about second corner fold line 10 so that the corner element 8 lies flat on the panel 6. Hot melt glue is then applied to the top face 8aa of the outermost portion of the corner post element 8, and the tab element 16 of the blank 1 is folded about the resistance fold line 18 to lie against the glued face 8aa, securing the tab element 16 against it.

[0035] Hot melt glue is then applied to the other face of the tab element 16, and the end wall 6 is folded inwardly about end wall fold lines 22 and outwardly about first floor fold line 23 so that the face of the tab element 16, and the corner post elements 8 lie flat on the floor 2. The side wall 4 is then folded inwardly about second floor fold line 24 until its end portion lies against the tab element 16 and is secured thereto by the hot melt glue.

[0036] Both ends of each side of the blank are treated simultaneously as described above, resulting in the box precursor shown in Fig. 8.

[0037] In a similar fashion to the first embodiment of the invention, to produce the box shown in Fig. 8, the side walls 4 are raised about the second floor fold lines 24 until they extend upwardly at right angles from the floor 2. This action pulls the end walls 6 upwardly about the first floor fold lines 23, simultaneously causing the end walls 6 to open out by hinging about the end wall fold lines 22.

[0038] In that position the end walls 6 are still partly folded inwardly about the first floor fold lines 23, and the corner post elements 8 have been pulled from their flat, stacked attitude into a rhombic cross-sectional shape.

[0039] From there the free end portion 26 of the end wall elements 6 are folded inwardly about free end fold lines 28 and this causes the end walls 6 to be pulled fully up until they extend at right angles from the floor 2; this in turn pulls the corner post elements 8 into a square cross-sectional shape. The folding is completed when the tab elements 16 fold about tab end fold lines 27 so that the tab elements 16 lie at an angle of approximately 90° to the free end portions 26, and the free end portions 26 extend parallel to the floor element 2 which produces an over-centre effect in locking the box structure in place as shown in Fig. 8.

[0040] As in the first embodiment, the over-centre effect takes the form of a slight bulge in an outwardly direction at a mid portion of each end wall 6.

[0041] The box precursor of the invention may be made of for example solidboard, corrugated board, graphic board, craft board, test board or plastic board, and may be coated, for example PE-coated, or uncoated.

Claims

1. A box precursor openable between a generally flat shape and a box defining shape, the box precursor having elements (8) expandable between the flat shape and the box defining shape to form corner posts, the box precursor including a resistance element (26) which in the box defining shape provides resistance against the box collapsing towards the flat shape.

2. A box precursor as claimed in claim 1 wherein the precursor has pre-formed fold lines allowing it to be opened out from the generally flat shape to form the box defining shape.

3. A box precursor as claimed in claim 1 or 2 wherein the elements (8) are corner elements (8) secured to or integral with the box precursor.

4. A box precursor as claimed in any preceding claim wherein the resistance element (26) comprises a free end portion (26) extendable along a top edge of a wall (4,6) of the box, allowing the free end portion (26) to be folded about the top edge to create an over-centre effect to lock the box in its opened-out position.

5. A box precursor as claimed in claim 4 wherein the free end portion (26) is connected to the top edge of the wall (4,6) of the box along a pre-formed fold line (28) .

6. A box precursor as claimed in any preceding claim wherein a second resistance element (26) is provided on a second wall (4,6) of the box.

7. A box precursor as claimed in Claim 6 wherein the resistance elements (26) are integral with the box precursor.

8. A box precursor as claimed in any of claims 3 to 7 wherein the corner elements (8) are integral with the box precursor.

9. A box precursor as claimed in Claim 8 wherein the corner posts are polygonal in cross-section.

10. A blank (1) for forming a box precursor, comprising a bottom panel (2) and a pair of first and second side wall panels (4,6) connected to the bottom panel (2), the blank (1) being provided with elements (8) for forming corner posts (8) in a box formed from the box precursor, at least one of the side wall panels (4,6) being provided with a resistance element (26) to resist collapse of the box.

11. A blank (1) for forming a box precursor as claimed in claim 10 wherein the bottom panel (2) and the first and second side wall panels (4,6) are connected along first and second bottom panel fold lines (24, 23), the second side wall panels (6) being provided with corner elements (8) connected with opposite ends of the second side wall panels (6) along corner edge fold lines (13), each corner element (8) having at least one fold line adapetd to facilitate folding of the corner elements (8) into the corner posts.

12. A blank for forming a box precursor as claimed in claim 10 or claim 11 wherein the resistance element (26) is connected with a top edge of the second side wall panel (6) along a free end fold line (28) the second side wall panel (6) and the resistance element being further provided with second side wall panel fold lines (22) extending at an angle of approximately 45° from opposite bottom end corner points of the second side wall panel (6) to a free edge of the resistance element (26).

13. A blank for forming a box precursor as claimed in claim 12 the resistance element (26) comprises resistance fold lines (18) extending at an angle of approximately 45° from corner points thereof adjacent the second side wall panel (6), and a securing tab element (16) to secure the corner posts (8) connected to opposite ends of the resistance element (26) along tab fold lines (27).

14. A blank as claimed in any of claims 10 to 13 wherein each of the second side wall panels (6) is provided with a resistance element (26).

15. A method for forming a box precursor comprising forming a blank comprising a bottom panel (2) and a pair of first and second side wall panels (4,6) connected to the bottom panel (2), the blank (1) being provided with elements (8) for forming corner posts (8) in a box formed from the box precursor, at least one of the side wall panels (4,6) being provided with a resistance element (26) to resist collapse of the box and folding the blank (1).

16. A method for forming a box precursor from a blank as claimed in claim 15 comprising the steps of, folding outer portions (8a) of the corner elements (8) of each second side wall panel (6) in an inwardly direction about the second corner fold lines 10, placing adhesive on portions (12) of the second side wall panels (6) adjacent the corner edge fold lines (13) and intermediate the side second side wall panel fold lines (22) and free end fold lines (28), further folding the corner elements (8) about corner edge fold lines (13) so that a face of the outermost portion (8aa) of each of the corner elements (8) lie against the adhesive portions (12) thus securing the outermost portions (8aa) against an end portion of the second side wall panels (6), applying adhesive to a free face of innermost portions (8bb) of the corner elements (8) and folding securing tab elements (16) about the resistance fold lines (18) to lie against and be secured to the innermost portions (8bb) of the corner elements (8), folding the second side wall panels (6) inwardly about the second bottom panel fold lines (23) and outwardly about second side panel fold lines (22) so that the second side wall panels (6), the corner post elements (8) and a free face of the tab elements (16) lie flat on the bottom panel (2), further applying adhesive to the free face of the tab elements (16) and folding the first side wall panels (4) inwardly about first bottom panel fold lines (24) so that end portions of the first side wall panels (4) lie against and are secured to the tab elements (16).

17. A method for forming a box precursor from a blank as claimed in claim 15 comprising the steps of, folding outer portions (8a) of the corner elements (8) of each second side wall panel (6) in an inwardly direction about the second corner fold lines 10, placing adhesive on portions (12) of the second side wall panels (6) adjacent the corner edge fold lines (13) and intermediate the side second side wall panel fold lines (22) and free end fold lines (28), further folding the corner elements (8) about corner edge fold lines (13) so that a face of the outermost portion (8aa) of each of the corner elements (8) lie against the adhesive portions (12) thus securing the outermost portions (8aa) against an end portion of the second side wall panels (6), applying adhesive to a free face of innermost portions (8bb) of the corner elements (8) and folding securing tab elements (16) about the resistance fold lines (18) to lie against and be secured to the innermost portions (8bb) of the corner elements (8), folding the second side wall panels (6) inwardly about the second bottom panel fold lines (23) and outwardly about second side panel fold lines (22) so that the second side wall panels (6), the corner post elements (8) and a free face of the tab elements (16) lie flat on the bottom panel (2), further applying adhesive to the free face of the tab elements (16) and folding the first side wall panels (4) inwardly about first bottom panel fold lines (24) so that end portions of the first side wall panels (4) lie against and are secured to the tab elements (16).

18. A box comprising a box precursor as claimed in any of claims 1 to 9.

19. A box comprising a blank as claimed in any of claims 10 to 14.

Drawing