GB2071620A - Carton blanks - Google Patents

Abstract

A carton blank for packaging fragile articles such as light bulbs include transverse fold lines (10 to 13) for forming an erected tubular body, one pair of side wall panels (15) having hingedly attached closure panels (18, 18%), which panels, when the blank is erected, extend in a reentrant manner into the carton to mutual engagement at an included angle of at the most 170 DEG and serve to retain the article. <IMAGE>

Description

SPECIFICATION Cartons and blanks therefor This invention relates to cartons and blanks therefor.

Particularly for the packaging of fragile articles such as domestic light bulbs there exists a need for a packaging carton which can be readily erected and charged with product and yet which provides satisfactory and reliable protection for the product to the point of use.

In accordance with the invention from one aspect there is provided a carton having a tubular body formed of first and second pairs of opposed side wall panels, at least one of the ends of the body being closed by an end closure which comprises closure panels individually hinged to respective wall panels of one of the said pairs and extending inwardly of the carton in a reentrant manner to mutual engagement at an included angle of at the most 1700.

In accordance with the invention from a second aspect there is provided an elongate blank for a carton, having transverse fold lines to form it with pairs of alternately disposed first and second side wall panels adapted in combination to provide a tubular body for the erected carton, along a side of the blank the side wall panels of one said pair having hingedly attached closure panels, the combined depths of the closure panels laterally of the blank being greater than the width, longitudinally of the blank, of each of the side wall panels of the other said pair whereby in the erected carton the closure panels may extend in a reentrant manner into the carton to mutual engagement at an included angle of at most 1700.

These and other aspects and features of the invention will now become apparent from the following description of embodiments of the invention, given by way of example and with reference to the accompanying drawings. In the drawings: Fig. 1 shows a blank for a packaging carton; Fig. 2 is a perspective view showing the carton formed from the blank of Fig. 1, in an intermediate stage of its erection; Fig. 3 is a view of the erected carton, as seen looking along the carton from its open end; Fig. 4 shows the carton in use, as seen generally on a central cross-sectional view taken along the line IV--IV in Fig. 3; Fig. 5 shows the erected carton, in a view similar to Fig. 3 but with an alternative mode of erection;; Fig. 6 shows the carton in its alternative mode of erection and as seen generally on a central cross-sectional view taken along the line VI--VI in Fig. 5; Fig. 7 is a scrap view showing the end closing arrangement of a second blank; and Fig. 8 is a similar scrap view of a third blank.

Referring now to Fig. 1 of the drawings, a paper-board blank for a carton for a domestic light bulb (e.g. 60 watts) is elongate and generally rectangular.

It is internally creased or scored along transverse hinge lines 10, 11, 12 and 13 and a longitudinally directed hinge line 14 to form four identical rectangular side wall panels 15, and a glue flap 1 6 at one end of the blank. Each of the hinge lines 10 to 14 extends across or along (as appropriate) the blank from one free edge to the free edge opposite.

The hinge line 14 separates the panels 1 5 and glue flap 1 6 from an end closing arrangement comprising two pairs of mutually opposed end panels. The end panels of the two pairs are attached to respective ones of the side wall panels 15 along the hinge line 14; they are attached to one another along the hinge lines 10 to 13 as shown.

The end panels of one pair (the "closure" panels) are generally rectangular, but one of the panels, denoted 18, terminates in a free edge 19 which is regularly curved so as to be concave to the panel 18.

The other closure panel, denoted 18', is wholly rectangular. At the centre of its terminal edge 20 it carries a small rounded locking tab 21 attached along a crease or score line 22. It is particularly to be noted that this line 22 is so formed as to create an indentation or groove on the surface of the paperboard which is to form the outer surface of the carton. Usually this surface, particularly over the side wall panels 15, will be printed with promotional or informative matter.

For the reason later to become apparent, tha combined depth (i.e. the dimension transversely of the blank) of the closure panels 1 8, 1 8' is somewhat greater than the width (i.e. the dimension longitudinally of the blank) of each side wall panel 1 5. The depth of the closure panel 18 is taken at the widest point of that panel, that is to say, at its centre.

The other end panels 25 of the end closure arrangement are identical and internally subdivided by articulating hinge lines. These hinge lines form each articulated panel 25 with an isosceles-triangular panel portion 26 attached by its base along the hinge line 14, generally triangular panel portions 27 attached by the hinge lines 10 to 13 to adjacent ones of the closure panels 18, 1 8' or the glue flap 1 6 (as appropriate), and triangular panel portions 28 joining the panel portions 27 to the panel portion 26 on each side of the latter. The hinge lines lying between the panel portion 26 and the panel portions 28 form common sides for those panel portion and are denoted 30; the hinge lines lying between the panel portion 28 and the panel portions 27 likewise form common sides for those panel portions and are denoted 31.On each side of each panel portion 26 the hinge lines 30, 31 are convergent at the respective crossing point of the transverse and longitudinal hinge lines 10 to 13, 14, the apical angles of the panel portions 26, 27, 28 at that point being approximately equal.

Each panel portion 27 provides a tab portion 33 by which it projects beyond the free edge 1 9 or 20 of the adjacent closure panel 1 8, 18' immediately on the other side of its respective transverse hinge line lotto 13.

In each articulated panel 25 the free side edges 34 of the panel portions 28 meet at the apex of the panel portion 26 to which the panel portions 28 are attached. The free side edges 35 of the panel portions 27 extend from the tab portions 33 at an inclination of approximately 450 to the hinge lines 10 to 13, 14, so as to meet the panel portions 28 at their apices formed between the hinge lines 31 and free side edges 34.

The blank is despatched to the packer (e.g. a domestic light bulb manufacturer) in the form of a generally plane tube flattened along the hinge lines 11, 13 and with the glue flap 16 glued or heat sealed to the outer marginal edge of the remote side wall panel 1 5 on the inside of the tube. At this time the closure panels 1 8, 1 8' and the articulated panels 25 are coplanar with the side wall panels 1 5 to which they are attached.

The end closure is formed automatically or manually by applying inward pressure firstly to the panel portions 26 and latterly to the closure panels 1 8, 18'. The pressure applied to the panel portions 26 forces them to move inwardly towards one another by folding along the hinge line 14.

As they move inwards the panel portions 26 carry with them the panel portions 28, the panel portions 27 and the closure panels 18, 18', which accordingly fold in relation to one another and to the panel portions 26 along the hinge lines 10 to 13,30and31.

Fig. 2 shows the carton at the time when the panel portions 26 have moved through an angle of approximately 450 from their original vertical positions. It will be seen that the panel portions 28 have folded outwards along the hinge lines 30 in relation to the panel portions 26, so as still to be approximately vertical (that is, parallel to the central axis of the carton), and the panel portions 27 have folded outwards along the hinge lines 31 in relation to the panel portions 28. The closure panels 18, 1 8' have folded inwards by a small angle (e.g. 200).

At approximately the position shown in Fig. 2 the pressure on the panel portions 26 is removed and substituted by inward pressure applied to the closure panels 1 8, 1 8'. This causes continued movement of the closure panels 1 8, 1 8' towards one another and continued folding of the panel portions 26, 27 and 28 towards the interior of the carton.

The forces exerted on the closure panels 1 8, 1 8' are so synchronised that the inward movement of the closure panel 1 8' is somewhat in advance of that of the closure panel 1 8. This enables the closure panels 1 8, 1 8' together with the associated panel portions 27 (which by this time are folded against the closure panels) to pass through the horizontai without interfering with one another despite the fact that, as previously mentioned, the combined depth of the closure panels 1 8, 1 8' is greater than the separation of the parts of the hinge line 11 at which those panels are attached.

The forces applied to the closure panels 1 8, 1 8' are continued so that both panels move within the carton interior in a reentrant manner and make progressively reducing acute angles with their respective side wall panels 1 5. Because of the advanced condition of the closure panel 1 8' the free edge 19 of the closure panel 1 8 (together with the associated tab portions 33) eventually come into contact with the back (i.e. trailing) face of the closure panel 18'; it thereafter rides down the closure panel 18' as the closure panels move in relation to one another.

Eventually, the rounded free edge 19 of the closure panel 18 engages in the groove formed by, score line 22 of the locking tab 21. The pressure on the closure panels 1 8, 1 8' is then removed after which resilience of the carton material along the hinge line 14 maintains the engagement of the closure panel 1 8 in the score line 22 and holds the end closure stably in its closed condition.

Fig. 3 shows the end closure as it appears looking down the square-section tubular side wall formed by the side wall panels 1 5. It will be seen that the closure panels 1 8, 1 8' form the major, end closing panels of the end closure.

It will furthermore be seen from Fig. 3 that the associated panel portions 27, 28 on each side of each panel portion 26 are folded against one another along their common hinge line 31 so as to form a gusset fold which projects into the carton interior beyond the engagement of the closure panels 1 8, 1 8' with one another as described above. For each panel portion 26 the free side edges 34,35 of the panel portions 27,28 forming the gusset folds define a double-walled, V-shaped notch having its apex directed towards the adjacent side wall panel 1 5. The two V-shaped notches formed within the carton interior in this way accordingly face away from one another.

The panel portions 26 lie closely adjacent their respective side wall panels and are not visible in Fig. 3.

The locking tab 21 projects into the carton interior but with an inclination (in relation to the central axis of the carton) in the direction towards the closure panel 18. The carton is charged with a domestic light bulb 80 in conventional manner by pushing the bulb, bulb portion first 81, into the carton from the open end. During this movement the front of the bulb portion engages snugly in the V-shaped notches formed by the gusset folds as described above.

At approximately the same time the bulb portion contacts the locking tab 21 and forces it further back towards the closure panel 18, so enhancing the locking action of that panel in the score line 22.

The movement of the bulb within the carton is completed when the bulb portion 81 engages the closure panel 18' at the score line 22. The gusset folds thereafter provide cushioning and lateral location for the bulb within the carton for transit and display. Further lateral location is provided by the side wall panels 1 5 which are dimensioned so that the bulb portion is a push fit into the tubular body, and by a square, apertured locating sheet 40 (Fig. 4) which in known manner is fitted over the screw or bayonet attachment 82 of the bulb and pushed part way along the carton to engage the side wall panels 1 5 at its side edges. Usually, the locating sheet 40 will be fitted on the bulb before the latter is inserted in the carton.

The function of the tab portions 33 is to augment the action of the free edge 1 9 and score line 22 (assisted by the locking tab 21) to lock the closure panels 18, 18' together. To achieve this the tab portions 33 of the trailing closure panel 18 enter the folds formed between the leading closure panel 18' and its adjacent panel portions 27 at the same time as the edge 19 and line 22 come into engagement; the tab portions 33 associated with the leading closure panel 18' serve to guide those of the trailing panel into position as the closure panels interlock with one another.

From Fig. 4 it will be readily understood that, by virtue of the inclination of the closure panels 18, 1 8' to one another, any axial loading imposed on the light bulb in relation to the carton during transit or display will tend to increase the locking engagement of those panels, so that there is little danger that the end closure as a whole will burst.

Furthermore, the closure panels space the bulb resiliently but firmly from the plane carton end formed along the hinge line 14, so substantially preventing the possibiiity of breakage of the bulb under normal loading conditions.

In a possible modification of the blank of Fig. 1 a shallow notch (not shown) is formed in the free edge 19 of the closure panel 18 for receiving the locking tab along its hinge line 22; such an arrangement assists initial location of the closure panels in relation to one another and by resisting any tendency for the free edges 1 9, 20 to slide along one another, contributes to the rigidity of the carton against non-uniform side loading.

An alternative mode in which the blank of Fig. 1 may be erected is depicted in Figs. 5 and 6, which respectively correspond to Figs. 3 and 4 already discussed. In this alternative form of erection the panel 18 is made the leading closure panel when the end closure is being formed, with the result that in the erected carton it lies generally inside the closure panel 1 8' as shown. Locking of the closure panels together is achieved by the tab portions 33 on either side of the closure panel 18', which enter the folds formed between the other tab portions 33 and the associated closure panel 1 8 in an analogous manner to that previously described for the first mode of erection.

In this alternative mode the tab 21 serves no locking function in the erected carton but lies against the outside face of the closure panel 1 8.

Its function is performed during the formation of the end closure. In order to engage its associated tab portions 33 into their locking positions, the closure panel 18' has to be depressed to such an extent that its free edge 20 is in danger of moving irreversibly beyond the free edge 1 9 of the closure panel 18. The tab 21 prevents such a passing movement and thereby ensures that, when the tab portions 33 have been located in position and the closure panels are subsequently released, the closure panels adopt relaxed positions with the free edge 20 of the closure panel 18' engaged, as shown, with the outside of the closure panel 18.

The hinge line 22 of the tab 21 (Fig. 1) may be omitted for the alternative mode of operation.

As an alternative to its application to the packaging of domestic light bulbs a further application proposed for the carton shown in Figs.

1 to 4 is as a holder for disposable cups. With such an application no locating sheet 40 is employed; the disposable cup is push-fitted into the carton to engagement with the end closure at the bottom end.

Fig. 5 shows a second end closure arrangement in accordance with the invention.

The end closure arrangement is in many respects similar to that of the embodiment of Figs.

1 to 4, and where appropriate the same reference numerals are used as before.

Like the first embodiment, the end closure arrangement is provided on a blank having equal width side wall panels 15 and a glue flap 1 6. It has a pair of gusset folding articulated panels 25 each subdivided by hinge lines to form panel portions 26, 27, 28, the panel portions 27 having tab portions 33.

The closure panels of this embodiment are identical and denoted 11 8. They have no locking arrangement but are centrally formed with identical semi-circular cut-outs 50.

In the erected carton the free edges of the closure panels 11 8 on either side of the cut-outs 50 engage one another edge-to-edge in pairs so as to maintain the closure panels in their desired end closing positions. Locking of the closure panels in these positions is effected by the tab portions 33 which function as before. The tab portions 33 adjacent the right closure panel in Fig. 5 are shorter than those adjacent the left closure panel, the right hand closure panel being made the trailing one of the closure panels as they are moved into their reentrant positions.

Fig. 6 shows a third end closure arrangement in accordance with the invention to be substantially identical to that of Fig. 5 with the exception of the closure panels.

The closure panels differ, and are accordingly denoted 218 and 218'.

The closure panel 218 has two projecting tongues 55 separated by a notch 56. The closure panel 218' has a central tongue 57 which is receivable by the notch so as to be interdigitated with the tongues 55 when the carton is erected.

It will be noted that the notch 56 is greater in depth than the closure panel 21 8 beyond the tongues 55 at either end of the panel; in addition, the closure panel 218' is relieved at 60 on either side of the tongue 57. It will thus be understood that in the completed end closure mutual engagement of the closure panels 218, 218' occurs primarily at the ends of the closure panels.

The tongues 55, 57 provide lateral relative location for the closure panels and project a substantial way into the carton interior to provide cushioning for an article packed in the carton.

Depending upon the shape of the articie, further cushioning may be provided by the gusset folds provided by the panel portions 27, 28. Locking in addition to that provided by the closure panels themselves is effected by tab portions 33 in the manner of the previous embodiments.

The invention is in no way to be considered as limited to the packaging of domestic light bulbs as particularly described, but may have application to the packaging of other articles, of a fragile nature or otherwise. With suitable arrangement, for example by the provision of an internal lining, it may be used for the packaging of particulate materials rather than individual items.

A carton embodying the invention may have end closures at each end rather than at only one end. These end closures may be in accordance with the invention and, it desired, identical, or one end closure may be conventional.

Although the included angle formed between the closure panels of each of the described embodiments is approximately 1400, the included angle formed between the closure panels of a carton in accordance with the invention may vary within wide limits and may be acute rather than obtuse. It is believed, however, that the included angle should be, at the most, 1 700 if the end closure is to have adequate resistance against product-generated loading.

To ensure that the closure panels are held securely in relation to one another in their closure forming positions, arrangements are possible other than those particularly described; these may or may not include end panels such as the articulated panels 25 of the described embodiments. For example, in one possible arrangement the closure panels are formed with interdigitable rows of teeth, and no other end panels are provided.

Cartons having cross-sections other than square (e.g. rectangular) are comprehended within the scope of the invention.

Claims (13)

1. A carton of foldable sheet material, having a tubular body formed of first and second pairs of opposed side wall panels, at least one of the ends of the body being closed by an end closure which comprises closure panels individually hinged to respective wall panels of one of the said pairs and extending inwardly of the carton in a reentrant manner to mutual engagement at an included angle of at the most 1700.

2. A carton according to claim 1, wherein the closure panels are formed with locking formations which are co-operable to lock the closure panels in their closing relation.

3. A carton according to claim 2, wherein the locking formations comprise an integral tab on one closure panel and a co-operating notch in the other panel, in which the tab is engageable.

4. A carton according to any preceding claim, wherein the end closure further comprises articulated panels each hinged to a respective wall panel of the other said pair of wall panels and further hinged to the closure panels on either side, the articulated panels providing respective pairs of gusset folds which project into the carton interior and are folded in relation to the closure panels.

5. A carton according to claim 4, wherein the articulated panels provide locking tabs adjacent their hinged connections with one of the closure panels, the locking tabs being engaged within the folds formed between the other closure panel and the adjacent gusset folds to lock the closure panels in their closing relation.

6. An elongate blank for a carton, formed of foldable sheet material having transverse fold lines to form the blank with pairs of alternately disposed first and second side wall panels adapted in combination to provide a tubular body for the erected carton, along a side of the blank the side wall panels of one said pair having hingedly attached closure panels, the combined depths of the closure panels laterally of the blank being greater than the width, longitudinally of the blank, of each of the side wall panels of the other said pair whereby in the erected carton the closure panels may extend in a reentrant manner into the carton to mutual engagement at an included angle of at the most 1700.

7. A blank according to claim 6, wherein the closure panels are formed with locking formations which are co-operable to lock the closure panels in their closing relation.

8. A blank according to claim 7, wherein the locking formations comprise an integral tab on one closure panel and a co-operating notch in the other panel, in which the tab is engageable.

9. A blank according to any claim of claims 6 to 8, which further includes articulated panels each hinged to a respective wall panel of the other said pair of wall panels and further hinged to the closure panels on either side, the articulated panels being adapted so as in the erected carton to provide respective pairs of gusset folds which project into the carton interior and are folded in relation to the closure panels.

10. A blank according to claim 5, wherein the articulated panels are adapted to provide locking tabs adjacent their hinged connections with one of the closure panels, the locking tabs being engageable, when the end closure is formed, within the folds formed between the other closure panel and the adjacent gusset folds to lock the closure panels in their closing relation.

11. A carton, substantially as hereinbefore described with reference to Figs. 3 and 4, or Figs.

5 and 6 of the accompanying drawings.

12. A blank substantially as hereinbefore described with reference to Fig.1 or Fig. 7 or Fig. 8 of the accompanying drawings.

13. A carton erected from a blank as claimed in claim 12.