GB2046220A - A blank for forming into a box - Google Patents

Abstract

A blank for an open-topped box has a base area 10, two side areas 16, two end areas 13 and four end flaps 15 connected one to each end of each side area 16. Each end flap 15 is separated from the adjacent end area 13 by a single cut 14, and is also divided into major and minor portions 22 and 23 by a further cut 21. Rim strips 19 are provided for strengthening. Glue is applied in strips 25, 26 and 27, and the box folded by turning over the two rim strips and then folding upwardly the two end areas 13 followed by the two side areas 16, whereafter the two major portions 22 and finally the two minor portions 23 are folded round to adhere to the two end areas 13. <IMAGE>

Description

SPECIFICATION A blank for forming into a box and a boxmaking method This invention relates to a blank suitable for forming into an open-topped box, and to a method for forming an open-topped box from such a blank. The invention is particularly but not exclusively--concerned with boxes suitable for perishable produce, such as tomatoes and especially mushrooms, and such boxes with open tops and handles are known generally as 'baskets'.

A known and very widely used design of mushroom basket is made by folding a blank appropriately preformed with fold-lines, cuts and punched-out portions, the folded blank then being stapled together to hold the folded shape. The manufacturing method thus requires several steps: a first in which a generally rectangular blank is provided with the required cuts and fold-lines or scores; a second in which various portions are removed by punching; a third in which the blank is folded; and a fourth in which the folded blank is stapled. The first two steps may require two or more sub-steps fully to complete the cutting, generation of fold-lines and punchingout, but all these steps can with relative ease be performed on automatic machinery.Even though the third step can be performed automatically, a blank generally is folded by hand, because it is not practical automatically to fold and then staple a blank, and transfer of an automatically folded blank to a manual stapling operation would result in great inefficiency, because the blank would tend at least partially to unfold.

Attempts have been made to staple folded blanks automatically, but these generally have not been adopted commercially. Not only is the required machinery most complicated -and hence expensive-but the machinery also is most prone to jamming-with consequent interruption of the entire box-making process. Even a step in which a blank has portions punched-out (such as the second step referred to above) tends to cause difficulties in high-speed production, because the punchedout portions too easily can become wedged in an operating part of the machinery, leading to interruption in the production.

For these reasons, despite increasing labour costs, much of the manufacturing process for open-topped produce boxes such as mushroom baskets is performed manually, as this currently is the most cost-effective method. It is an aim of this invention to provide a blank suitable for forming into an open-topped box and which can be so-formed automatically, as well as a method for producing an opentopped box from such a blank.

According to one aspect of this invention, there is provided a blank suitable for forming into an open-topped box, which blank is in the form of a substantially rectangular piece of sheet-like material divided into a plurality of areas by means of cuts and of fold-lines, the areas thus defined comprising a rectangular base, a pair of sides and a pair of ends respectively connected by fold-lines to opposed side edges and end edges of the base, each side having connected thereto by a foldline a rim strip which lies alongside the edge of the side parallel to the side edge of the base, each side also having two end flaps connected one to each of the other two edges respectively of the side, there being a fold-line extending for at least part of the length of the junction between each side and its associated end flap, each rim strip extending beyond the respective side to lie alongside both adjacent end flaps, each end flap being separated from the adjacent end by a cut extending generally parallel to or co-linear with the adjacent side edge of the base and each end flap also being divided into major and minor portions by a further cut extending from the free edge of the blank substantially to the junction between the end flap and the associated side, the minor portion being connected both to the adjacent rim strip by a fold-line and to the adjacent side, and the fold-line connecting the rim strip both to the side and the minor portion of an end flap being cut through along its length in the region of the interconnection between the minor portion of the end flap and adjacent side.

The fold-lines themselves can be lines along which the blank has partially been cut through (i.e. score lines) or lines along which local pressure has been applied to reduce the thickness of the material forming the blank.

Another possibility is for a fold-line to be defined by a series of aligned cuts each spaced from the next but passing right through the material of the blank.

In the following, the face of the blank which will, when the box has been folded, form the inside walls of the box will be referred to as the 'inside' and the face which will form the external walls will be referred to as the 'outside'.

The blank of this invention is especially intended for automatic or semi-automatic folding and securing of the folded parts to form a finished box. The securing most conveniently is performed with adhesives, though stapling could be used for instance in a semi-automatic process. Moreover, the manufacture of the blank itself does not entail the punching-out of portions from the main area of the blank, thereby reducing the required number of steps in producing the blank. This advantage is enhanced by having the cuts which separate the end flaps into major and minor portions, and the cuts which separate the end flaps from the associated ends, formed as single cuts extending generally linearly and substan tially parallel to the fold-lines between the base and the adjacent sides.

The box when folded from the blank could have sides and ends which upstand essentially perpendicularly from the base, but in order to facilitate storage of folded boxes by nesting it is preferred for the sides and ends to flare outwardly by a degree sufficient to allow nesting of a stack of folded boxes. To allow this, the two cuts separating each end from the two adjacent end flaps should, whilst being generally parallel to the adjacent side edges of the base, have a separation which increases towards the free edge of the blank.

Such cuts thus give the end a greater width at the open top to the box than at the base.

Though such cuts should connect to the respective fold-line along the base side edge and should be generally linear, it is nevertheless advantageous for each cut to be turned to lie substantially parallel to the base side-edge for a portion of the length of the cut adjacent the free edge of the blank. Such a formation ensures that the sides of the box, when folded, are constrained to flare outwardly for the greater part of their length, and yet the region thereof adjacent the open top may lie generally perpendicular to the base portion.

In a similar way, the separation between the fold-lines interconnecting each side and the associated end flaps should increase away from the base portion; this ensures that the ends also flare outwardly when folding of the box is completed.

The fold-lines between each end flap and its associated side may extend for the full length of the junction between the end flap and the side, and if required also continue across the adjacent rim strip to the free edge of the blank. However, this fold-line may instead extend solely from the fold-line connecting the side and base up to the cut separating the end flap into major and minor portions. This latter fold-line allows the upper corners of a folded box to be slightly rounded, adding to the strength as well as giving an edge which can bear on the next lower box in a column of nested boxes, helping to prevent nested boxes jamming, one within another.

The blank may be made from any of the usual materials used for produce boxes, such as cardboard or paperboard. The preferred material for a mushroom box is a relatively thin cardboard which may have a plastics film adhered to one face-which face will form the outside of the finished box.

The blank of this invention could be folded appropriately and then stapled to hold the folded blank in the shape of an open-topped box. However, the blank lends itself to mechanical folding and securing by means of an adhesive, automatically to produce a finished open-topped box.

Thus, according to another aspect of this invention, there is provided a method of producing an open-topped box from a blank as defined above of this invention, which method comprises the steps of: (a) applying adhesive on the outside of at least the rim strip extension adjacent a minor portion of an end flap at all four corners, or on the minor portion itself at all four corners; (b) folding the two rim strips over along their entire lengths, so that the rim strip extensions adhere to the respective minor portions of the end flaps, thereby to form tabs; (c) applying adhesive to the inside of the major portion of each end flap; (d) folding each end upwardly and then folding the adjacent major portions of the two end flaps round to adhere to the folded end; (e) applying adhesive to the inside of the minor portion of each end flap forming a part of a tab; and (f) folding each tab round to overlie at least partially one of the already-folded end and end flap, to adhere thereto.

To allow the application of adhesive in as few a steps as possible, steps (c) and (e) above may be performed either simultaneously or immediately consecutively, the folding and adhering steps (d) and (f) then following in order.

Adhesive may be applied in relative narrow strips running generally parallel to the side edges of the base, on the relevant areas.

Thus, the application of such adhesive is most conveniently effected mechanically, whilst the blank is being advanced along a production line for automatic folding. Preferably, a hotmelt adhesive with a cycle time of about 2 seconds is employed, such an adhesive losing sufficient heat in two seconds (taking into account the various parameters of the production process) that the adhesive thereafter no longer is tacky.

When the blank is folded fully mechanically, it is preferred for the folding to be performed in two distinct stages; namely, a first stage in which adhesive applying step (a) above is carried out immediately whereafter the rim strips are folded over in step (b), and a second stage in which adhesive applying steps (c) and (e) above are carried out immediately whereafter folding steps (d) and (f) above are carried out. In a practical realisation of the method, the blank may be inverted between the two distinct folding stages, the blank starting with the outside uppermost and then after inversion having the inside uppermost.

In the second stage, a handle may be attached to the box. For instance, simultaneously with the folding of the blank, a metal strip may be folded to a U-shape to fit within the box mid-way between the ends, and then two rivets inserted one through each rim strip and the interfitting handle. Then, the handle may be pivoted round through 180 , ready for use, or left within the box if a plurality of boxes are to be nested in a stack.

The two cuts provided along the fold-line of each rim strip are to allow easy folding of the tabs each comprising the minor portion of an end flap and the overlying part of the adjacent rim strip. Without such a cut, the rim strip would tend to bulge outwardly on folding of the tab, especially where the cuts and foldlines are formed to ensure the uppermost parts of the sides extend generally perpendicular to the base.

The dimensions of a mushroom basket made from a blank of this invention may be essentially identical to those of known mushroom baskets, by appropriate dimensioning of the various areas of the blank-that is, by appropriate positioning of the various foldlines and cuts. It may be advantageous for certain sizes to trim the length of the tabs comprising the overlying parts of the rim strips and minor portions of the end flaps, to ensure that the tabs do not overlap when folded. In this way, a neat and well-finished product may be obtained.

The invention extends to a box whenever made from a blank of this invention as described above, especially but not exclusively when made by the method also as described above.

By way of example only, two specific examples of blanks of this invention and a method of making an open-topped box with one of the blanks will now be described in detail, reference being made to the accompanying drawings, in which: Figure 1 is a plan view of the first embodiment of cut blank for folding into a mushroom box; Figure 2 is a detail view showing the method of folding an end of the box from the blank of Fig. 1; and Figure 3 is a detail view of a part of the second embodiment of cut blank.

The blank shown in Fig. 1 is produced from a rectangular sheet of cardboard material and has a plurality of distinct areas defined by fold-lines and cuts. The fold-lines are shown in broken lines and are produced in the cardboard material by applying local pressure along a line to reduce the thickness of the cardboard, whereas the cuts are shown in thickened lines and are produced by a knife arranged to sever the cardboard material.

The blank has a rectangular base area 10 disposed centrally, the base area being defined by linear side fold-lines 11 and linear end fold-lines 1 2. Two ends 1 3 are connected to the base by the respective end fold-lines 12, the ends also being defined by cuts 1 4 separating the ends from end flaps 1 5. Two sides 1 6 are connected to the base by the respective side fold-lines 11, each side also being defined by fold-lines 1 7 connecting the end flaps 1 5 thereto, and a rim fold-line 1 8 connecting a rim strip 1 9 thereto.Each rim strip 1 9 extends beyond its associated side to lie alongside the adjacent end flap, being connected thereto by means of a continuation of the rim fold-line 1 8. This fold-line 1 8 is however cut through in the region 20 of the fold-lines 17, as shown. Further cuts 21 separate each end flap into a major portion 22 and a minor portion 23.

To ensure that the box, when folded from the blank of Fig. 1, flares outwardly to an extent sufficient to allow nesting of a plurality of such boxes, neither the ends nor the sides are rectangular. Instead, the separation between both the cuts 14 defining an end 1 3 and between the fold-lines 1 7 defining a side 1 6 increases away from the base 10, but the furthest end portions of the respective cuts or fold-lines are parallel. So far as the sides are concerned, these parallel end portions extend from the further cuts 21 to the rim fold-line 18, and the parallel end portions of the end cuts 14 are of a similar length.

For the particular embodiment of blank shown in the drawings, for folding into a mushroom box, the free ends of the rim strips 1 9 together with the associated parts of the minor end flap portions 23 are cut off to be shorter than the length of the major portions 22 of the end flaps. This is done to prevent the free ends of the rim strips on opposite sides of a folded box from overlapping, but whether or not this is necessary depends upon the precise dimensions of the blank and finished box.

The blank described above may be folded into a finished box automatically by suitable machinery, the various overlapping areas being adhered together as folding processes. In Fig. 1, the various places to which adhesive is applied are shaded; areas 25 have adhesive applied to the face of the blank which will be the outside of the finished box and areas 26 and 27 have adhesive applied to the other side of the blank. The adhesive used is preferably a hot-melt adhesive having a cycle time of about 2 seconds, and so should be applied immediately prior to folding of the relevant part to be adhered.

After the cuts and fold-lines have been produced in the blank as described above, the blank can be advanced to a glueing and folding machine, where initially areas 25 have glue applied thereto from the underside, for instance by a simple roller immersed in a bath of the glue. Then, the rim strips 1 9 are folded over, to adhere the rim strips 1 9 to the sides 1 6 and the extension portions 1 9a to the respective immediately-adjacent minor portions 23 of the end flaps, thereby to define tabs for use subsequently in holding the box together. Glue is then applied to areas 26 on the major portions 22 of the end flaps and to areas 27 on the minor portions of the end flaps, for instance by pressure jetting units from above.

In one further operation, by forcing the blank into a suitable cavity by means of appropriate operating members, the folding and glueing can be completed. The ends 1 3 are folded upwardly in the direction of arrow A (Fig. 2), whilst the sides are also folded upwardly in the direction of arrow B until the edge of each end lies adjacent the fold-line 1 7 at the end of each side.Then the major portions 22 of the end flaps are wrapped round the ends 1 3 and pressed into contact therewith, to adhere together the ends 1 3 and end flaps 1 5. Finally, the tabs (made up of the minor portions 23 and the extension portions 1 9a of the rim strips adhered together) are folded round the ends 1 3 and urged downwardly at the same time as indicated by arrow C, so that the tabs adhere partly to the end flaps and partly to the ends.This operation ensures that the sides follow the shape of the edges of the ends, and particularly the parallel end portions of the cuts 1 7. In this way, the upper portions of the sides and ends lie generally perpendicular to the plane of the base 10, the cuts 20 allowing the rim strips to be deformed in this way, without bulging outwardly.

At the same time as the further folding operation, a handle may be affixed to the box.

Such a handle is shown at 30, and comprises a strip of metal-such as thin sheet steel or aluminium-with the long edges turned over to eliminate sharp edges. The strip is bent into a U-shape, for example by being pressed into a folded box, and two rivets 31 inserted one through each end of the handle and through the turned over rim strip 1 9 of the box. Bifurcated rivets conveniently are used, and may be driven through the box material and handle without the need to preform holes.

To use the handle, it is simply pivoted round through 180 to upstand from the box; when however left as shown, boxes when completed may be nested in a stack.

Referring now to Fig. 3, there is shown the corner portion of a second embodiment of blank which generally is similar to that described with reference to Fig. 1, and like areas, lines and so on are given like reference characters. The blank differs however in the following respects.

Fold-line 1 8 has been replaced by double fold-line 18a, this double line having two parallel, closely-spaced lines of reduced thickness. Moreover, the region of the fold-line 1 8 between the cut 20 and the free edge of the blank is defined by a series of aligned cuts 18b, each of relatively short length and closely spaced to the next adjacent cut, shown in Fig. 3 by a chain line. Lastly, the fold-line 1 7 extends solely from the junction between fold-lines 11 and 12 up to the cut 21 separating the end flap 1 5 into its major and minor portions 22 and 23.

The second embodiment of blank is folded to form a box in precisely the same manner as the first embodiment, and may, when folded, be stapled to hold the box together or may be glued, automatically if desired, as the folding progresses. The double fold-line 1 8a serves to broaden the width of the top edge of the sides of the folded box, and hence to add to the strength and rigidity. The lack of a fold-line from cuts 21 up to the free edges tends somewhat to allow rounding of the upper parts of the corners, again adding rigidity but moreover allowing the lower edge (when folded over) of the rim strip to bow out slightly. This forms an edge which, when folded boxes are nested for storage, may bear on the next box below on the nested stack.

This prevents two boxes becoming jammed together which otherwise can occur if the rim strip of an upper box forces its way into the mouth of the next box below. The perforated fold-line 1 8b allows a particularly sharp crease to be achieved, but the reduction in strength thereby obtained is of little consequence since the ends of a folded box already have more than one thickness of material, adhered together.

Claims (20)

1. A blank suitable for forming into an open-topped box, which blank is in the form of a substantially rectangular piece of sheetlike material divided into a plurality of areas by means of cuts and of fold-lines, the areas thus defined comprising a rectangular base, a pair of sides and a pair of ends respectively connected by fold-lines to opposed side edges and end edges of the base, each side having connected thereto by a fold-line a rim strip which lies alongside the edge of the side parallel to the side edge of the base, each side also having two end flaps connected one to each of the other two edges respectively of the side, there being a fold-line extending for at least part of the length of the junction between each side and its associated end flap, each rim strip extending beyond the respective side to lie alongside both adjacent end flaps, each end flap being separated from the adjacent end by a cut extending generally parallel to or co-linear with the adjacent side edge of the base and each end flap also being divided into major and minor portions by a further cut extending from the free edge of the blank substantially to the junction between the end flap and the associated side, the minor portion being connected both to the adjacent rim strip by a fold-line and to the adjacent side, and the fold-line connecting the rim strip both to the side and the minor portion of an end flap being cut through along its length in the region of the interconnection between the minor portion of the end flap and adjacent side.

2. A blank as claimed in claim 1, wherein the fold-line between each end flap and its associated side extends for the full length of the junction between the end flap and side.

3. A blank as claimed in claim 2, wherein the fold-line between each end flap and its associated side is continued across the adjacent rim strip to the free edge of the blank.

4. A blank as claimed in claim 1, wherein the fold-line between each end flap and its associated side extends from the region of the fold-line connecting the side and the base to the cut separating the end flap into major and minor portions.

5. A blank as claimed in any of the preceding claims, wherein the two cuts separating each end from the two adjacent end flaps have a separation which increases towards the free edge of the blank.

6. A blank as claimed in claim 5, wherein the two cuts are generally linear but each cut is turned to lie substantially parallel to the base side-edge for a portion of the length of the cut adjacent the free edge of the blank, so that the sides flare outwardly when a box is folded from the blank.

7. A blank as claimed in any of the preceding claims, wherein the separation of the fold-lines between each side and its associated end' flaps increases away from the base portion, so that the ends flare outwardly when a box is folded from the blank.

8. A blank as claimed in any of the preceding claims, wherein each cut respectively separating each end flap into major and minor portions and separating each end flap from the associated end is defined by a single generally linear cut extending substantially parallel to the fold-lines between the base and the adjacent sides.

9. A blank as claimed in any of the preceding claims, wherein the fold-line separating each minor portion of the end flaps and the adjacent rim strip extension is defined by a succession of spaced cuts arranged linearly.

10. A blank as claimed in any of the preceding claims, wherein the blank is made of cardboard or paperboard having a plastics film adhered to one face thereof.

11. A blank for folding into an opentopped box, substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.

1 2. A method of producing an opentopped box from a blank as claimed in any of the preceding claims, which method comprises the steps of: (a) applying adhesive on the outside of at least the rim strip extension adjacent a minor portion of an end flap at all four corners, or on the minor portion itself at all four corners; (b) folding the two rim strips over along their entire lengths, so that the rim strip extensions adhere to the respective minor portions of the end flaps, thereby to form tabs; (c) applying adhesive to the inside of the major portion of each end flap; (d) folding each end upwardly and then folding the adjacent major portions of the two end flaps round to adhere to the folded end; (e) applying adhesive to the inside of the minor portion of each end flap forming a part of a tab; and (f) folding each tab round to overlie at least partially one of the already-folded end and end flap, to adhere thereto.

1 3. A method as claimed in claim 12, in which adhesive is applied in relative narrow strips running generally parallel to the side edges of the base, on the relevant areas.

14. A method as claimed in claim 1 2 or in claim 13, in which a hot-melt adhesive with a cycle time of about 2 seconds is employed.

1 5. A method as claimed in any of claims 1 2 to 14, in which the blank is folded fully mechanically, and the folding is performed in two distinct stages during the first of which adhesive applying step (a) is carried out immediately whereafter the rim strips are folded over in step (b), and a second stage in which adhesive applying steps (c) and (e) above are carried out immediately whereafter folding steps (d) and (f) above are carried out.

16. A method as claimed in claim 15, in which a handle is attached to the box during the second stage.

1 7. A method as claimed in claim 16, in which a metal strip is folded simultaneously with the folding of the blank to a U-shape to fit within the box mid-way between the ends, and then two rivets are inserted one through each rim strip and the interfitting handle.

1 8. A method of folding a blank substantially as hearinbefore described, with reference to the accompanying drawings.

19. An open-topped box whenever made from a blank as claimed in any of claims 1 to 11.

20. An open-topped box as claimed in claim 19, whenever made by a method according to any of claims 12 to 1 8.