GB2335653A

GB2335653A - End closure for tubular carton formed from blank

Info

Publication number: GB2335653A
Application number: GB9806404A
Authority: GB
Inventors: Patrick Doran; David Dowling
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-03-24
Filing date: 1998-03-25
Publication date: 1999-09-29
Also published as: GB9806404D0; IES80525B2; IES980219A2

Abstract

A carton is formed from a blank (Fig. 3) by first folding it to form a tubular body with a rectangular cross section which is closed by end panels 30, 36 extending from each side panel 10, 12, 14, 16. A pair of dust flaps 30 extending from opposite side panels 10, 14 are folded towards each other to partially close the opening. A pair of closure flaps 36, 36'joined to the remaining panels 12, 16 are then folded to lie one upon the other over the dust flaps. The underlying closure flap 36' is configured, preferably by forming a rebate 42 on each side of it, to reveal a part 44 of each of the dust flaps so that the overlying closure flap may be adhesively secured to the revealed parts. In addition, the parts of the overlying closure flap 46 and the dust flaps 44 which join may be embossed so that they lie out of the plane of the surrounding blank by approximately one half the thickness of the blank so that they can be joined without distortion due to the intervening thickness of the centre portion 40.

Description

1 A CARTON FORMED FROM A FOLDED BLANK 2335653 This invention relates to a

carton formed from a folded blank, and to a blank which is foldable to form such a carton.

Fig. 1 shows a known blank for forming a carton, and Figs. 2A to 2C show how the known blank is folded to form the carton.

The known blank comprises first, second, third and fourth rectangular panels 10, 12, 14 and 16 respectively, which are joined each to the next along parallel edges defined by fold lines 18, 20 and 22.

The panels 10 and 14 are the same size and shape, as are the panels 12 and 16, while the panels 10 and 14 are narrower than the panels 12 and 16 as measured in the direction normal to the fold lines 18, 20 and 22. A narrow flap 24 is joined by a further fold line 26 to the free edge of the panel 16.

The body of a carton is formed, Fig. 2A, by f olding each panel 10, 12, 14 and 16 at right angles to the next along the respective fold line between the two, and gluing the flap 24 along the inside of the free edge 34 of the panel 10. The panels 10 and 14 form one pair of opposite parallel sides of the carton body, and the panels 12 and 16 form the other pair of opposite parallel sides of the carton body. Thus the 2 body of the carton has a rectangular cross-section and a corresponding rectangular opening 28 at each end.

The manner of closing the opening 28 at each end of the carton body will now be described with reference to Figs. 2A to 2C, it being understood that Figs. 2A to 2C show one end only of the carton, the other end being formed in substantially identical manner.

At each end of the carton body the blank has a pair of dust flaps 30 joined by fold lines 32 to the ends of the first and third panels 10 and 14 respectively. These dust flaps 30 are folded each towards the other at right angles to the adjoining panel 10 or 14 so as to extend towards one another partially across the opening 28 at that end of the body, Fig. 2A. Since the length d, Fig. 1, of each dust flap 30 is less than half the width W of the panels 12 and 16, the free ends of the dust flaps 30 do not meet.

At each end of the carton body the blank fur-ther has a pair of closure flaps 36 joined by fold lines 38 to the ends of the second and fourth panels 12 and 16 respectively. These closure flaps 36 are folded each towards the other at right angles to the adjoining panel 12 or 16 so as to lie one upon the other across the opening 28 at that end of the body. Fig. 2B shows the situation when the closure flap 36 joined to the 3 panel 16 has been folded down across the opening 28, i.e. onto the dust flaps 30, and Fig. 2C shows the situation when the other closure flap 36 has been folded down onto the first closure flap. in this case the length d of each closure flap 36 is substantlally the same as the width w of the panels 10 and 14, so that each closure flap substantially covers the opening 28. The facing surfaces X, Fig. 2B, of the closure flaps 36 are glued together to secure the end of the carton.

This known carton has the disadvantage that-the closure at each end of the carton is relatively weak. Thus, excess pressure on the panels 12 and 16, as may occur for example on the bottom cartons in a stack of filled cartons, tends to "spring" the closure such that the glued flaps 36 tend to lift and may ultimately part.

It is therefore an object of the invention to provide an improved carton of the above type.

Accordingly, the invention provides a carton formed from a folded blank, the blank comprising first, second, third and fourth rectangular panels joined along parallel edges and folded each at right angles to the next to form the body of the carton having a rectangular cross-section and a corresponding rectangular opening at each end, a first pair of flaps 4 joined to the ends of the first and third panels respectively and folded each towards the other at right angles to the adjoining panel so as to extend towards one another partially across the opening at that'ena of the body, and a second pair of flaps joined to the ends of the second and fourth panels respectively and folded each towards the other at right angles to the adjoining panel so as to lie one upon the other across the opening at that end of the body, wherein the underlying one of the second pair of flaps is configured to reveal a part of the surface of each of the first pair of flaps and the overlying one of the second pair of flaps is adhesively secured to the revealed parts of the first pair of flaps.

7 i It is to be understood that terms such as "parallel", "right angle", "rectangular" and the like used herein are not to be interpreted with mathematical precision, and each such term is to be interpreted as 20 if the word "substantially" were inserted before it.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein:

Fig. 1, previously described, shows a known blank for forming a carton; Pigs. 2A to 2C, previously described, show how the known blank is folded to form the carton; Fig. 3 shows one side of a blank which is foldable to form a carton according to the embodiment of the invention; Fig. 4 shows the other side of the blank of Fig.

3; a Figs. SA to 5C, which correspond respectively to the views shown in Figs. 2A to 2C, show how the blank of Fig. 3 is folded to form the carton according to the embodiment of the invention; Fig. 6 is an end view of the carton according to the embodiment of the invention; Fig. 7 is a cross-secticn of the carton of Fig. 6 20 taken along the line 7-7 of Fig. 6; Fig. 8 is a cross-section of the carton of Fig. 6 taken along the line 8- 8 of Fig. 6; Fig. 9 is a croSS-Section of the carton Of Pig. 6 taken along the line 9- 9 of Fi97. 6; and Fig. 10 is a cross-section of the carton of Fig. 6 taken along the line 10-10 of Fig. 6.

6 Referring now to Figs. 3 to 10, the carton according to the embodiment of the invention is -folded from a blank whose two opposite sides are shown in Figs. 3 and 4 respectively. As compared to Fig. 3, the side of the blank shown in Pig. 4 is hatched in order to permit the two sides of the carton to be distinguished in Figs. SA to SC.

Since the blank shown in Figs. 3 and 4, and the resultant carton folded therefrom, is in many r"pects the same as that shown in Fig. 1, the same reference numerals have been used for the same or similar elements. The following description will therefore is focus on the improvements in the blank of Figs. 3 and 4 as compared to the known blank of Fig. I.

In the blank of Pigs. 3 and 4, the closure flap:61 joined to the end of the panel 16 (i.e. the -flap equivalent to the flap 36 in Fig. 1) is configured to have a central portion 40 with a rebate 42 on each side. Thus, when the closure flap 361 is folded down onto the dust flaps 30, Fig. SR, a part 44 of each dust flap 30 is revealed.

1 Now, when the closure flap 36 joined to the end of the panel 12 is folded down over the closure flap 361, Fig. SC, parts 46 (Figs. SA and 5B) of the closure flap 36 come to lie directly over the revealed parts 44 of 7 the dust flaps 30 without the material of the closure flap 361 intervening.

In this case, to secure the end of the carton, the parts 46 of the overlying closure flap 36 are glued directly to the revealed parts 44 of the dust flaps 30, while the portion of the closure flap 36 between the parts 46 is glued to the central portion 40 of the underlying closure flap 361 intermediate the revealed parts 44 of the dust flaps 30. This is indicated by the X's in Fig. 5B.

As a further improvement on the blank of Fig. 1, it is advantageous to have the revealed parts 44 of the dust flaps 30, and the parts 46 of the overlying closure flap 36 which are glued thereto, slightly raised out of the plane of the surrounding blank each in the direction towards the part adhesively secured thereto, in particular by approximately one half the thickness of the blank. This is shown most clearly in Figs. 7 to 10, and can be effected by the same die which cuts the original blank. By raising the parts 44 and 46 in this manner they can be brought into face to face contact without distortion of the blank due to the intervening thickness of the centre portion 40.

The advantage of the invention is that a far more robust closure is achieved at the ends of the carton, leading to greater strength and ability to resist 8 pressure on the panels 10 and 14. Cartons made according to the invention have been capable of stacking to a height 20k to 30% than equivalent prior art cartons as illustrated in Fig. 1

The greater strength of the closure also permits a reduction in the size of the closure flaps 36 and 361. Thus, in the embodiment, the length d, Fig. 3, of each closure flap 36, 361 is significantly less than the width w of the panels 10 and 14, so that each closure flap extends only partially across the opening 28 at each end of the carton body. This means that a blank of smaller area can be used for the same carton capacity, giving a substantial saving on 'raw material on large production runs.

It will also be appreciated that cartons made according to the invention reduce the outflow of cold air from the inside of the carton with the advantage that the carton contents may be retained in a frozen state for a longer period at lower cost. Further, the nature of the closure of a carton according to the invention enhances the security of the carton against any potential infestation by bugs/insects.

9

Claims

1. A carton formed from a folded blank, the blank comprising first, second, third and fourth rectangular panels joined along parallel edges and folded each at right angles to the next to form the body of the carton having a rectangular crost-section and a corresponding rectangular opening at each end, a first pair of flaps joined to the ends of the first and third panels respectively and folded each towards the other at right angles to the adjoining panel so as to extend towards one another partially across the opening at that end of the body, and a second pair of flaps joined to the ends of the second and fourth panels respectively andfolded each towards the other at right angles to the adjoining panel so as to lie one upon the other across the opening at that end of the body, wherein the underlying one of the second pair of flaps is configured to reveal a part of the surface of each of the first pair of flaps and the overlying one of the second pair of flaps is adhesively secured to the revealed parts of the first pair of flaps.

2. A carton as claimed in claim 1, wherein the overlying one of the second pair of flaps is also adhesively secured to the underlying one of the second pair of flaps intermediate the revealed parts of the first pair of flaps.

3. A carton as claimed in claim 2, wherein the underlying one of the second pair of flaps comprises a central portion with a rebate on each side, the rebates revealing the parts of the first pair of flaps, the overlying one of the second pair of flaps being adhesively secured to the central portion of the underlying one of the second pa-4-- of flaps and to the iS parts of the first pair of flaps revealed by the

4. - - - - - A ca ton as cla4med in cla-.-n 3, where4n the underlying one of the second pair of flaps Is T-s.haped, said rebates being rectangular and th.e sum of thei-r w-dc.-.s, measured parallel to the len.gch of cae cross f C1 -11 -arm o he T, bef-g greater than half of sa4-;

5. A carton as claimed i.-any preceding --'-a--,n,

6. A carton as claimed in any preceding claim, wherein the second pair of f laps also extend only partially across the opening at that end of the body.

1

7. A blank which is foldable to form a carton as claimed in any preceding claim.

3. A carton as claimed in claim 2, wherein the underlying one of the second pair of flaps comprises a central portion with a rebate on each side, the rebates revealing the parts of the first pair of flaps, the overlying one of the second pair of flaps being adhesively secured to the central portion of the underlying one of the second pair of flaps and to the parts of the first pair of flaps revealed by the 10 rebates.

4. A carton as claimed in any preceding claim, wherein the revealed parts of the first pair of flaps and/or the parts of the overlying one of the second pair of flaps adhesively secured thereto are slightly raised out of the plane of the surrounding blank -each in the direction towards the part adhesively secured thereto.

5. A carton as claimed in claim 4, wherein the revealed parts of the first pair of flaps and the parts of the overlying one of the second pair of flaps adhesively secured thereto are raised out of the plane of the surrounding blank by approximately one ha lf the 25 thickness of the blank.

6_ A carton as claimed in any preceding claim, wherein the second pair of flaps also extend partially across the opening at that end of the body.

11 7. A blank which is foldable to form a carton as claimed in any preceding claim.

8. A carton substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings. 9. A blank substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

1 k -2- Amendments to the claims have been filed as follows CLAIMS is 1. A carton formed from a folded blank, the blank comprising first, second, third and fourth rectangular panels joined along parallel edges and folded each at right angles to the next to form the body of the carton having a rectangular cross-section and a correspending rectangular opening at each end, a first pair of.-.!-aps joined to the ends of the first and third panels respectively and folded each towards the other at right angles to the adjoining panel so as to extend towards one another martially across the opening at that end of' the body, and a second pair of flaps joined to the ends of the second and fourth panels respectively and folded each towards the other at right angles to the ad' _ i -janel so as to lie one unon the other across the opening at that end of thle body, wherein the under--.V--nz one of the second LO-Iaps is not adhes.-",.rely secured to the first pair cf- flaps and is con'-c-icn-:r-2d reveal a part of the surface of each of the -first pa.1r C.ic- flans and the overlying ene of the second pair cIA' C-1 t --,% 2. A carton as claimed in claim 1, where-in the overlying one of the second pair of flaps is also adhesively secured to the underlying one of the second pair of flaps intermediate the revealed parts of t.he first pair of flaps.