AU8399882A

AU8399882A - Gable topped cartons

Info

Publication number: AU8399882A
Application number: AU83998/82A
Authority: AU
Inventors: Hedley Simon Bryant; Terence Edwin Florida
Original assignee: Mardon Son & Hall Ltd
Current assignee: MARDON SON AND HALL Ltd
Priority date: 1981-05-14
Filing date: 1982-05-13
Publication date: 1982-12-07

Description

GABLE TOPPED CARTONS TECHNICAL FIELD

This invention relates to gable topped cartons such as may be used, for example, for containing liquids such as milk or fruit juice. BACKGROUND AST

Gable topped cartons are widely used for packaging liquids for human consumption such as milk or fruit juice. A known gable topped carton has two outer roof panels extending from opposite side walls of the carton and meeting one another at a top seal, and two generally triangular gable panels extending respectively from front and rear walls of the carton and connected to the outer roof panels by inner roof panels which meet the adjacent gable panels along gable creases.

DISCLOSURE OF THE INVENTION

According to one aspect of the present invention, at least one of the gable creases deviates from a straight line between the ends of that gable crease. This feature reduces the stress set up in the material of the carton, makes the carton easier to open and reduces the tendency of the carton to buckle inwardly along the crease between the respective gable panel and the adjacent wall of the carton. In a preferred embodiment, the gable creases between both of the gable panels and their inner roof panels are not straight. The gable creases may be arcuate, and, where the carton is square in cross-section, the radius of the arc may be approximately double the length of each side. Alternatively, the gable creases may follow a non- arcuate curve, or they may each comprise two or more mutually inclined straight portions. According to another aspect of the present invention, the front and rear inner roof panels terminate at front and rear inner seal lips respectively, the front inner seal lips each having a top edge which is lower at a position between its ends than it is at its ends. This feature can provide a sealing area of reduced efficiency, so making the carton easier to open.

According to another aspect of the present invention, the outer roof panels and the gable panels meet the respective walls at respective creases of which the central portions are copIanar with one another, each crease terminating in an end portion which deviates from the line of the central portion of the crease. This feature reduces bunching of the material of the carton at the top creases of the carton. BRIEF DESCRIPTION OF DRAWINGS

Figure 1 shows the upper portion of a blank for erection into a gable-topped carton:

Figure 2 shows the upper portion of the erected carton; Figure 3 is a side view of the carton of Figure 2;

Figure 4 shows the carton of Figures 2 and 3 during opening; and

Figure 5 shows the fully opened carton. BEST MODE OF CARRYING OUT TEE INVENTION The blank shown in Figure 1 is made from fully bleached sulphite board provided on both faces with a thermoplastic coating. The blank comprises two side wall panels 2 and 4, a front wall panel 6 and a rear wall panel 8. Outer roof panels 10 and 12 are hinged respectively to the side walls 2 and 4 along creases 9, and these panels terminate in outer seal lips 14 and 16 respectively. Creases 18 run through the panels 10 and 12, to assist folding of these panels upon opening of the carton, as will be described later.

Generally triangular front and rear gable panels 20 and 22 are hinged respectively to the front and rear wall panels 6 and 8 along creases 19« The creases 9 have upwardly deflected end portions 9A and the creases 19 have downwardly deflected end portions 19A. This feature reduces bunching of the material at the upper corners of the panels 2, 4 , 6 and 8 when the carton is erected, while enabling the creases 9 and 19 to be colinear.

The gable panels 20 and 22 are connected to the adjacent outer roof panels 10 and 12 by front and rear inner roof panels 24 and 26 respectively. The gable panels 20 meet the inner roof panels 24 and 26 along gable creases 25. The rear inner roof panels 26 terminate at their upper edges in rear inner seal lips 28, and the front inner roof panels 24 terminate at their upper edges in front inner seal lips 30. The front inner seal lips are symmetrical about a crease 32 at which they meet each other. The front inner seal lips meet the adjacent inner roof panels 2k along creases 33 which slope upwardly away from the crease 32. The upper edge of each front inner seal lip extends from the crease 32 in a concave curve which merges into a straight portion parallel to the respective crease 33. The apex formed by the meeting of the curved portions of the top edges of the front inner seal lips is at approximately the same level as, or slightly above, the outer ends of the straight portions of these top edges.

A seam flap 34 is connected to the panels 4 , 12 and 16. During erection of the carton, this flap 34 is bonded to the panels 8, 22, 26 and 28 and the blank is formed into a tube.

An important feature of the blank shown in Figure 1 is that the gable creases 25 between the gable panels 20 and 22 and the adjacent inner roof panels 24 and 26 are not straight. In the embodiment illustrated, these creases.25 are arcuate, with a radius of curvature of 150 mm, the width of each panel 2, 4, 6 and 8 being approximately 70 mm.

The construction of the base of the carton is not shown in aηy of the Figures, because it has no bearing on the present invention. There are a number of suitable base constructions available. The erected, closed carton is shown in Figure 2.

It is erected in the conventional manner. The outer seal lips 14 and 16 are brought together, the gable panels 20 and 22 being pushed inwardly between them. The inner roof panels 24 and 26 are folded relative to the gable panels 20 about the gable creases 25 and lie adjacent the inner surfaces of the outer roof panels 10 and 12. Pressure is applied to the outer seal lips 14 and 16 and this, together with the application of heat to the thermoplastic coating of the blank material, causes the inner seal lips 30 to be sealed together, and both pairs of inner seal, lips 28 and 30 to be sealed to the outer seal lips 14 and 16, so forming a primary seal. Furthermore, the top edge regions of the out er seal lips 14 and 16 are sealed together to form a secondary seal.

Figure 3 is side view of the top of the carton. This figure shows diagrammatically the positions of the front and rear inner seal lips 28 and 30. Figure 3 shows the top edges of the sealing lips 28 to extend parallel to the top edges of the outer sealing lips 14 and 16.

Sealing of the carton is preferably effected using a pair of jaws which are stepped along a horizontal line, the position of which is indicated by dashed line 35 in Figure 3. The reason for stepping the jaws is to take account of the fact that only two layers of material are present at the upper region of the outer seal lips 14 and 16, while four layers are present at the lower region of the outer seal lips 14 and 16. It will be appreciated that the hatched area in Figure 3 will be subjected to a lower sealing pressure than the other areas of the top seal, because it is engaged by a portion of the jaws adapted for four layers of material; whereas only two layers are present. The hatched area is thus provided with a less efficient seal than the other parts of the top seal, which makes it easier to open the carton as will be described below. The projecting apex formed by the curved portions of the front inner seal lips 30 lies close to, or abuts, the reverse crease between the rear inner seal lips 28, so reducing the possibility of leakage through the tapering gap 37 between the front and rear inner seal lips.

To open the carton, the portions of the outer roof panels nearer the front wall 6 are folded outwardly of the carton along the creases 18, taking with them the front inner roof panels 24. This breaks the secondary seal between the outer seal lips 14 and 16 as well as the seal between the front inner seal lips 30. The inner seal lips 30 can then be drawn outwardly of the carton to break the seal between the inner seal lips 30 and to form a pouring spout as shown in Figure 5. The creases 18, like the creases 25, are arcuate but, in the illustrated embodiment they are curved in the opposite sense (in the closed carton) and have a slightly greater radius of curvature, for example, 157mm. This configuration assists in the opening of the carton.

By making the gable creases 25 arcuate instead of straight, a number of advantages are achieved. Firstly, the arcuate creases reduce the stresses set up in the material of the carton when it is erected. Also, the curved creases enhance the "overcentre" action provided by the resilience of the outer roof panels when the carton is opened to form the pouring spout. This causes the gable panel 20, the front inner roof panels 24, the front inner sealing lips 30 and the pouring lip 32 to flip outwardly when the pouring lip 32 is pulled. This feature, together with the reduced sealing efficiency immediately above the top edges of the front inner seal lips 30 and the arcuate creases 18, make the carton easier to open than has previously been the case.

Another advantage of the arcuate creases is that the carton is less likely to buckle inwardly along the creases at the top of the front and rear walls 6 and 8.

Although the present invention has been described with reference to a carton having a vertically upwardly projecting top seal, it can also be applied to cartons having a slanting top seal, which provides improved stacking characteristics. To achieve such a carton the crease between the outer roof panel 10 and the outer sealing lip 14 may be lower than the corresponding crease between the outer roof panel 12 and the outer sealing lip 16. INDUSTRIAL APPLICABILITY Cartons as described can he made liquid-tight and are thus suitable for the packaging of, for example, milk and fruit juices.

Claims

1. A gable topped carton having two outer roof panels (10, 12) extending from opposite side walls (2, 4) of the carton and meeting one another at a top seal

(14, 16), and two generally triangular gable panels

(20, 22) extending respectively from front and rear walls (6, 8) of the carton and connected to the outer roof panels (10, 12) by inner roof panels (24, 26), characterized in that at least one of the inner roof panels (24, 26) meets the adjacent gable panel (20, 22) . alongy a gable crease (25) which deviates from a straight line between the ends of the gable crease (25).

2. A gable topped carton as claimed in claim 1, characterized in that each of the gable creases (25) at which at least one of the gable panels (20, 22) meets the adjacent inner roof panels (24, 26) deviates from a straight line between the ends of the respective gable crease (25).

3. A gable topped carton as claimed in claim 2, characterized in that each of the gable creases (25) at which each gable panel (20, 22) meets the adjacent inner roof panels (24, 26) deviates from a straight line between the ends of the respective gable crease (25).

4. A gable topped carton as claimed in claim 1, characterized in that the or each deviating gable crease (25) is curved.

5. A gable topped carton as claimed in claim 4, characterized in that the or each deviating gable crease (25) is arcuate.

6. A gable topped carton as claimed in claim 5, characterized in that the radius of curvature of the or each arcuate gable crease (25) is at least double the width of the wall (6, 8) from which the adjacent gable panel (20, 22) extends.

7. A gable topped carton as claimed in claim 1, characterized in that the or each deviating gable crease (25) comprises at least two mutually inclined portions.

8. A gable topped carton as claimed in claim 1, characterized in that each outer roof panel (10, 12) is provided with an opening crease (18) disposed adjacent a respective one of the gable creases (25) of one of the gable panels (20, 22).

9. A gable topped carton as claimed in claim 8, characterized in that each opening crease (18) deviates from a straight line between the ends of that gable crease (18).

10. A gable topped carton as claimed in claim 9, characterized in that each opening crease (18) deviates to one side of the straight line between its ends and the adjacent gable crease (25) deviates to the other side of the straight line between its ends.

11. A gable topped carton as claimed in claim 10, characterized in that each opening crease (18) is arcuate and each of the adjacent gable creases (25) is arcuate, the radius of curvature of each opening crease (18) being greater than the radius of curvature of the adjacent gable crease (25).

12. A gable topped carton as claimed in any one of the preceding claims, in which the gable creases (25) of each gable panel (20, 22) meet at the top of the respective gable panel (20, 22).

13. A gable topped carton having two outer roof panels (10, 12) extending from opposite side walls (2, 4) of the carton and terminating in outer seal lips (14, 16) which meet one another at a top seal, and two generally triangular gable panels (20, 22) extending respectively from front and rear- walls (6, 8) of the carton and connected to the outer roof panels (10, 12) by front and rear inner roof panels (24, 26 ) respectively which terminate at front and rear inner seal lips (30, 38) respectively, characterized in that each front inner seal lip (30) has a top edge which is lower at a position between its ends than it is at its ends.

14. A gable topped carton as claimed in claim 13, characterized in that the top edge of each front inner seal ϊip (30) comprises a first portion which slopes downwardly from the adjacent outer seal lip (14, 16) towards/the other front inner seal lip (30), and a second portion which slopes upwardly from the first portion to the junction between the two front inner seal lips (30).

15. A gable topped carton as claimed in claim 14, characterized in that the second portion is curved. lβ. A gable topped carton as claimed in claim 15, characterized in that the second portion is curved concavely.

17. A gable topped carton as claimed in claim 14, characterized in that the first .portion is straight.

18. A gable topped carton as claimed in claim 17, characterized in that the first portion is parallel to a crease (33) at which the respective front inner seal lip (30) meets the adjacent front inner roof panel (24).

19. A gable topped carton having two outer roof panels (10, 12) extending from opposite side walls (2, 4) of the carton and meeting one another at a top seal (14, 16), and two generally triangular gable panels (20, 22) extending respectively from front and rear walls (6, 8) of the carton and connected to the outer roof panels (10, 12) by inner roof panels (24, 26), the outer roof panels (10, 12) and the gable panels (20, 22) meeting the respective walls (2, 4, 6, 8) at respective creases (9, 19) characterized in that the central portions of the creases (9, 19) are coplanar with one another and in that each crease (9, 19) terminating in an end portion (9A, 19A) which deviates from the line of the central portion of the crease (9, 19).

20. A gable topped carton as claimed in claim 19, characterized in that the end portions (9A) of the creases (9) between the outer roof panels (10, 12) and the side walls (2, 4) deviate upwardly from the central portions of those creases (9), and in that the end portions (19A) of the creases (19) between the gable panels (20, 22) and the front and rear walls (6, 8) deviate downwardly from the central portions of those creases (19). 21. A blank for erection into a carton in accordance with any one of the preceding claims.