DE69603486T2 - HANDLE FOR CARTON PACKAGING - Google Patents

Description

This invention relates to packages provided with reinforced handles. The invention, although not limited to this use, has a particular advantage for packages formed from corrugated cardboard having an incorporated reinforcing tape.

In previously known corrugated packages, the tape is usually applied to the fluting between the flute and the outer linerboard during the cardboard manufacture and is usually made of uniaxially oriented plastic materials approximately 11 mm wide. Blanks are die cut from the cardboard in such a way that the tape runs around the outer surface of the resulting packages, running longitudinally through the package handle, down the package sides and into the package bottom.

It has generally been found necessary to provide a relatively long anchoring section of the tape into the blank material on each side of the handle. With conventional handle designs, the tape-to-board bond otherwise tends to fail, particularly under impact loads, allowing the tape to tear out of the blank material and allowing the handle to tear. The need for long tape anchoring sections has thus far proven to be a limiting factor in the design of packages with incorporated reinforced handles.

We have discovered that by suitable construction of a handle and adjacent cut panels it is possible to produce a reinforced handle sufficiently durable for practical purposes which does not require long reinforcing anchorage sections.

In order to transfer a significant portion of the handle load to the non-reinforced handle end and the non-reinforced plate material, it is necessary that the non-reinforced material does not crack at the junction between the handle end and the plate. To this end, stress concentrations must be avoided which otherwise tend to initiate and propagate cracking.

In previously known handle constructions, the connection between the plate and the handle was slightly curved to avoid stress concentrations. In some packaging constructions, the handle end has edges formed by cuts running into the plate and ending at some distance from the upper edge of the plate. Such handle ends are used, for example, when the holder of the handle is cut off from a top plate of the packaging and, in use, is pulled up out of the plane of the top plate, the handle ends being folded inwards. In known packaging handle constructions of this type, as shown, for example, in DE-U-79 01 421, the ends of the cuts are slightly curved and divergent to avoid stress concentrations. This approach is satisfactory where a relatively long reinforcement anchorage section is used, which will tend to relieve the cut ends of transverse and shear stress. However, where only short anchorage sections are provided, there will be significant transverse and shear stresses on the cut ends, which will serve to concentrate the applied load locally at the cut tips, leading to rupture. Therefore, an alternative approach is required to relieve the stress concentrations.

The present invention accordingly provides a reinforced handle having an end portion directly attached to a packaging panel in which the reinforcement terminates, the end portion having edges formed by a pair of divergent cuts cut into the panel thereby enabling a substantial proportion of the load applied to the handle to be transferred from the reinforcement to the non-reinforced material of the end portion, characterized in that the cuts terminate in load-relieving apertures formed in the plate. Such apertures are less susceptible to tearing under transverse and shear loading. The divergent cuts ensure that the load of the handle tends to clamp the end edges against the plate, enabling load transfer between the plate and the end edges. In this way, the load-bearing capacity of the handle is increased.

To prevent the panel from stretching under the clamping action of the end edges, the panel may be secured (e.g. by gluing) to an overlying side of the package at areas adjacent to the end edges. Such an overlying side may additionally or alternatively be secured to the panel at areas beyond the ends of the cuts forming the end edges for transferring load from the package side into the panel and handle. The panel may thereby form a relatively short adhesive tab attached to the top panel in the package. Such an arrangement was not previously thought possible because it was believed to provide insufficient reinforcement anchorage length. To provide a greater length of handle to transfer load from the reinforcement to the non-reinforced handle material, the handle end edges may converge outside the panel boundary.

The invention will be further explained with reference to the illustrative embodiments shown in the drawings, in which:

Fig. 1 shows details of a packaging blank;

Fig. 2 shows details of the blank of Fig. 1 assembled; and

Fig. 3 shows another cut in its entirety.

In Fig. 1, a handle 10 is shown separated from an adhesive end flap 12 and a top panel 14 of a packaging blank 16 by cuts 18, 20. A reinforcing tape 22 of a conventional material is incorporated into the paperboard in a conventional manner, but oriented to pass through the top panel 14 and adhesive panel or flaps 12 rather than through the top panel 14, side panels 24 and a bottom panel (not shown) as would be the usual arrangement to provide sufficient tape end anchorage. The handle 10 has a portion of uniform width defined by parallel parts 18a, 20a of the cuts and a portion of increasing width defined between diverging parts 18b, 20b of the cuts. The extended handle portion is located partly in the upper plate 14 and partly in the adhesive end tab 12.

The blank has end panels 26 which are folded during assembly to overlay the adhesive end flap 12 as shown in Fig. 2. These end panels 26 are joined to the side panels 24 by panels 28 which form beveled corners in the assembled package. The shape of the package corners is not critical, however; they could equally be rectangular (not shown) or multi-faceted or rounded (as shown in Fig. 3 and described further below). Adhesive beads or strips 30, 32, 34 are applied to the adhesive end flap 12 to secure it to the adjacent end panels 26. A small gap is formed in the middle of the adhesive strips 30 and 32 to prevent unpredictable adhesive leakage between the meeting edges of the panel 26.

The cuts 18, 20 terminate in stress-relieving openings 38, 40 formed in the adhesive end flap 12. The adhesive strip 30 is applied to the flap slightly above the openings 38, 40 so as to traverse the cuts 18, 20. The outer portions of the adhesive strip 30 serve to anchor the parts of the flap 12 by securing these parts to the overlying end plates 26 to which they are secured against expansion under the clamping action of the extended portion of the handle 10. The adhesive strips 32 are disposed beneath the openings 38, 40 to transfer applied loads from the adhesive end tab 12 into the end plates 26 and also to prevent the end plates 26 from stretching under the clamping action just discussed.

When the handle 10 is lifted from the top plate 14, those handle portions positioned in the adhesive end tabs 12 will tend to pivot into the interior of the package. Under high impact, the bond formed by the inner portions of the adhesive strips 30 could break. In this case, however, the opposite sides of each cut 18b, 20b adjacent to the openings 38, 40 will still remain sufficiently coplanar to overlie one another and provide the necessary clamping action with associated load transfer between the handle and the adhesive end tabs 12.

The adhesive strips 34 serve primarily to attach the upper corners of the end plates 26 to the adhesive end tab 12.

Fig. 3 shows a blank for a 3 x 2 multi-pack designed to carry six 1 liter bottles of non-alcoholic beverages. In assembly, the end panels 26 are folded and secured by adhesive strips (not shown) to overlay the adhesive end tabs 12 forming sloping shoulders conforming to the bottle necks within the package. Further end panels 26' are foldably attached to the end panels 26 and the side panels 24 and have multi-part vertical notches at 41 to form multi-part facets conforming to the corner quadrants of the bottles. A bottom panel 42 is also provided. The handle reinforcement (not shown) is incorporated in the blank material and runs over the length marked aa in Fig. 3. It will be seen that the length is much shorter than the length bb over which the reinforcement tape is conventionally applied. However, tests have shown that a handle in general as shown in Fig. 1 has a static breaking strength of 60 kg (approx. 600 N); the handle is 25 mm wide at its central portion, 50 mm wide between the centers of the openings 38 and 40, has a length of 50 mm in the adhesive end flaps and a tapered length of 40 mm in the top panel 14, the adhesive end flap must have a minimum size of 90 x 90 mm and the paperboard composition comprises 140 g/m² kraft liner, 112 g/m² corrugation (E), 125 g/m² kraft liner. The package is designed for 6 x 33 cl beer bottles weighing a total of about 2 kg (20 N) and thus the handle strength is clearly sufficient, even under shock loads which would normally occur when the package is carried. A similar static breaking strength can be achieved with the handle and cut of Fig. 3, which is again sufficient to withstand an expected static load of around 6 kg (60 N) and shock loads due to carrying.

Claims (6)

1. A reinforced handle (10) having an end portion which is directly attached to a stack plate (12) in which the reinforcement (22) terminates, the end portion having edges formed by a pair of divergent cuts (18, 20) extending into the plate (12) thereby allowing a substantial portion of a load applied to the handle (10) to be transferred from the reinforcement (22) to the non-reinforced material of the end portion; characterized in that the cuts (18, 20) terminate in load-relieving openings (38, 40) formed in the plate (12). 2. A handle according to claim 1, wherein a side (26) of the package overlies and is secured to the plate (12) at regions adjacent to the end portion edges (18, 20), whereby the package side (26) inhibits the plate (12) from tearing under the clamping action of the end portion edges (18, 20). 3. Handle according to claim 1 or 2, wherein the end portion edges (18, 20) converge outside the plate boundary (12). 4. Handle according to one of the preceding claims, in which one side (26) of the package is supported at areas beyond the ends of the cuts for load transfer The plate (12) is superimposed on and secured to the plate (12) by the passage from the package side (26) into the plate (12) and the handle (10). 5. A package comprising a handle (10) reinforced according to any one of the preceding claims. 6. An assembleable blank to form the package of claim 5.