SE1051342A1 - Stackable cardboard lid - Google Patents

Abstract

The invention relates to a stackable cardboard lid (1, 1a, 1b, 1c, 1d), comprising: a substantially flat lid element (2) intended to cover an opening in a container when the lid (1) is applied to the container, said lid element (2) having an upper side (2a) and a lower side (2b) where the lower side (2b) is intended to face the container when applying the lid (1); a lower flange (3) extending along the outer edge of the lid element (2) and at least partially downwards from the lower side (2b) of the lid element (2) to allow cooperation with the container when applying the lid (1); and an upper flange (4) extending along the outer edge of the lid element (2) on the upper side (2a) of the lid element (2), the lid (1) being arranged such that a lower flange (3b) of a first lid (1b) overlaps at least a part of the upper flange (4c) of a second lid (1c) when the first and second lids (1b, 1c) are stacked on top of each other. The invention is that the distance between the outer periphery of the upper flange (4) and an imaginary center line through a center point (C) on the lid element (2) is, at least over the distance where the lower flange (3b) of the first lid (1b) overlaps at least a part of the the upper flange (4c) of the second lid (1c) when stacked, substantially equal to or less than the distance between the inner periphery of the lower flange (3) and said center line in an arbitrary position along the outer edge of the lid element (2). (Figure 5)

Description

In this context it can be noted that it is much more difficult to give cardboard lids a suitable design for stacking than plastic lids because cardboard lids are formed by assembling and forming one or more flat cardboard parts while plastic lids by molding can be given in virtually any shape. In addition, plastic lids can subsequently be thermoformed plastically to a much greater extent than cardboard lids because a cardboard material has a tendency to crack in the event of excessive deformation.

DISCLOSURE OF THE INVENTION The object of this invention is to provide a stackable cardboard lid which has improved stacking properties than existing lids of this type.

This object is achieved with a lid according to claim 1. Depending on the claims advantageous invention. embodiments, developments and variants of the invention relate to a stackable cardboard lid, comprising: a substantially flat lid element intended to cover an opening in a container when the lid is applied to the container, said lid element having an upper side and a lower side where the lower side is intended to face the container when applying the lid; a lower end extending along the outer edge of the lid member and at least partially downwardly from the lower side of the lid member to allow co-operation with the container when applying the lid; The upper invention is characterized in that the distance between the outer periphery of the upper end and an imaginary center line through a center point of the lid element is, at least over the distance where the lower end of the first lid overlaps at least a part of the upper end of the second lid when stacked, substantially equal to or less than the distance between the inner periphery of the lower flange and said center line in an arbitrary position along the outer edge of the Iockey element.

This means that the lower end of a lower Iock fits inside a lower flange (skirt) of an upper Iock without getting stuck. In other words, the upper and lower ar ends of the lid are arranged in such a way that when placing a first lid on a second lid, where the underside of the lid element (lid mirror) of the first lid faces the top of the lid element (lid mirror) of the second lid, the underside of the lid mirror of the first, upper lid in such a position that said underside abuts the upper, lower lid of the second lid.

This prevents the lower flange of the first upper lid from getting stuck in the second, lower upper lid of the second lid, even when the upper lid is lifted off. In addition, a stable stack of lids is formed because the weight rests on the upper side of the upper flange and not on an angled lower flange as in e.g. DE 4429057 where there is a great risk that increased stacking weight leads to an increased tendency for the lids to get stuck in each other and a risk that the stack will tip over.

In a preferred embodiment of the invention, the height of the upper flange over the upper side of the lid element and the shape and extent of the lower flange from the lower side of the locking element are adapted so that the lower flange is not appreciably pressed against a corresponding lower flange on an adjacent lid. plural lids.

This means that the upper flange is high enough, and that the lower flange is sufficiently well designed, to avoid the lower flanges pinching each other when stacking lids, i.e. to prevent the lower flange of an upper Iock from pinching into the lower flange of an underlying Iock. This can be achieved by i) making the upper flange so high relative to the lower flange that the lower flanges do not overlap at all when stacking lids, ii) designing the lower flange in such a way that a distance is formed between the inside of the lower part of an upper lid flange and the outside of the lower flange of a lower lid when stacking lids, iii) design the lower flange in such a way that the inside of the lower flange of a lower lid abuts only very lightly against the outside of the lower flange of a lower lid at stacking of lids, ie so light that the lower lid does not follow up when the upper lid is lifted, and / or iv) give at least a part of the lower flange a certain angle to the center line / vertical line, which angle in cooperation with the height of the upper gör end makes the lid lower flanges never rest on each other or only so lightly that they do not stick even if they partially overlap each other.

In a preferred embodiment of the invention, the lid is provided with a ledge which runs circumferentially outside the upper flange, the outer edge of the ledge merging into the lower flange. The upper flange is thus slightly retracted towards the center point of the lid mirror compared to the lower flange so that a distance is created between the respective bases of the upper and the lower end. In this way, an improved clearance is created between the lower flange of an upper lid and the upper flange of a lower lid when stacking lids.

In a preferred embodiment of the invention, the lower end is provided with a bulge running circumferentially on the inside of the lower flange, which bulge is intended for co-operation with an upper part of the container when the lid is applied to the container.

In a preferred embodiment of the invention, the lid is built up of a first, flat unit and a second, annular unit, the first unit constituting the lid element and the second unit forming at least a part of both the lower and the upper flange.

In a preferred embodiment of the invention, the first unit is provided with a folded rim along its outer edge, an upper part of the second unit being formed around and against said rim, the upper flange being formed by the upper part of the second element and said rim. In a preferred embodiment of the invention, the upper edge circumferentially has a waveform or pleated shape. As a result, an increased amount of surplus material can be taken care of.

In a preferred embodiment of the invention, the upper flange is substantially flat and extends substantially perpendicularly up from the upper side of the lid element.

DESCRIPTION OF THE FIGURES The invention will now be described in more detail with reference to the following figures, in which: Figure 1 shows a perspective view obliquely from below of a preferred embodiment of a carton lid according to the invention, Figure 2 shows a bottom view of the embodiment according to Figure 1, Figure 3 shows a section AA, with magnification, according to Figure 2, Figure 4 shows a section BB, with magnification, according to Figure 2, and Figure 5 shows a number of cardboard lids according to Figure 1 stacked on top of each other.

PREFERRED EMBODIMENTS Figure 1 shows a perspective view obliquely from below of a preferred embodiment of a stackable cardboard lid 1 according to the invention. The lid 1 comprises a substantially flat lid element 2 intended to cover an opening in a container (not shown) when the lid 1 is applied to the container. The lid element 2 has an upper side 2a and a lower side 2b where the lower side 2b is intended to face the container when applying the lid 1. A point C indicates a center point on the lid element 2.

The lid 1 further comprises a lower flange 3 (skirt) which extends along the outer edge of the lid element 2 and substantially downwards from the lower side 2b of the lid element 2 to allow cooperation with the container when applying the lid 1.

The lid 1 is also provided with an upper flange 4 which extends along the outer edge of the lid element 2 on the upper side 2a of the lid element 2. The upper flange 4 has in circumferential shape an undulated shape, i.e. waves or folds 5 are arranged in the upper flange 4 in a direction substantially perpendicular to the upper side 2a of the lid element.

Figure 2 shows a bottom view of the embodiment according to Figure 1, Figure 3 shows a section AA, with enlargement, according to Figure 2, and Figure 4 shows a section BB, with enlargement, according to Figure 2. As can be seen from the enlargement in Figure 4 in particular, the lid 1 is built up of a first, flat unit and a second, annular unit, the first unit constituting the lid element (lid mirror) 2 and the second unit constituting the lower flange 3 and a part of the upper fl end 4. The first unit is provided with a folded rim 6 along its outer edge, an upper part 40 of the second unit being formed around and against said rim 6.

Thus, the upper edge 4 is formed by the upper part 40 of the second unit and said rim 6.

The upper part 40 of the second unit is glued to the rim 6 and the upper flange 4 thus formed is pressed flat with wave-shaped (undulated) tools which has given rise to the waves / folds 5. In this flattening moment the upper flange 4 is brought inwards towards the center point C so that a ledge 9 is formed. The ledge 9 runs circumferentially outside the upper flange 4, the outer edge of the ledge 9 merging into the lower flange 3. This ledge 9 thus defines a distance between the base of the upper fl end 4 and the base of the lower fl end 3. This avoids that the lower flange 3 on an upper cover sticks to / against the corresponding flange 3 on a lower cover when stacking without the lower flange 3 having to be given an excessively extreme shape which can lead to cracking.

Due to the undulated shape (waves / folds 5), more excess material can be taken up in the upper flange 4, which is thus moved naturally inwards in the corner of the lid 1 and becomes stiffer and more dimensionally stable even on the shavings of the lid 1. The tools for the plating torque can be heated to about 160-250 ° C to make the cardboard material more malleable and make it stay reshaped as it cools. The flattening means that the upper flange 4 has a substantially flat shape and that it extends substantially perpendicularly up from the upper side 2a of the cover element 2.

The lower flange 3 is provided with a bulge 7 running circumferentially on the inside of the lower flange 3 (and a corresponding bulge 8 on the outside of the lower flange 3). The bulge 7 is intended for cooperation with an upper part of the container, e.g. a lip, in order to hold the lid 1 in place when the lid 1 has been applied to the container.

Figure 2 shows i.a. that a lower part 30 of the lower flange 3 (see figure 4) has a larger angle outwards from the lid 1 at the sides of the lid than at the rounded corners of the lid.

Figure 5 shows a number of cardboard lids 1a-1d according to figure 1 stacked on top of each other.

Lids 1a-1d are i.a. fitted with corresponding lower and upper flanges 3a-3d, 4a-4d. Furthermore, a lid element 2d is indicated for lid 1d. As can be seen in Figure 5, each lid 1a-1d according to the preferred embodiment is arranged in such a way that the lower flange 3b of a first lid 1b completely overlaps the upper flange 4c of a second lid 1c, seen in the height direction of the stack, when the first and second lids 1b, 1c are stacked on top of each other.

As shown in figure 5 together with e.g. Figure 4 is the distance between the outer periphery of the upper flange 4, i.e. the outside of the upper flange 4, and an imaginary center line through the center point C of the lid element 2 smaller, at least over the distance where the lower flange 3b of the first lid 1b overlaps the upper end 4c of the second lid 1c when stacked ie the inside of the bulge 7 in the preferred embodiment (e.g. bulge 7b on lid 3b), and said center line in an arbitrary position along the outer edge of the cover member. In other words, the lower flange 4c of a lower lid 1c fits inside a lower skirt 1b (skirt) of an upper lid 1b without getting stuck. This can be achieved even if the lower flange 3 has a different design so that the inner periphery of the lower flange 3 within the overlapping distance does not coincide with the inside of the bulge 7.

The imaginary center line passes through the center point C and has a direction perpendicular to the base element 2. The distances compared above thus correspond to imaginary, radial and parallel lines with the core element 2 between the imaginary center line and the outer periphery of the upper flange and the inner periphery of the lower flange. In Figure 5, these imaginary distances are horizontal while the imaginary center line is vertical. The distances referred to are thus radial distances.

Furthermore, it can be seen from Figure 5 that the height of the upper flange 4 over the upper side 2a of the lid element 2 and the shape and extent of the lower flange 3, i.e. for example length and angle, from the lower side 2b of the lid element 2 are adapted in such a way that the lower flange, e.g. 3b, is not appreciably pressed against a corresponding lower end, e.g. 3c, on an adjacent lid when stacking a plurality of lids. According to Figure 5, a small distance arises between the lower flanges, e.g. between 3b and 3c, when stacking. In the corner of the lid 1, where the lower flange has a smaller angle outwards from the lid 1, the flanges 3b and 3c can abut slightly against each other but without pinching each other so that removal of one lid from another in a stack is made more difficult.

The first and second units that make up the cover 1, i.e. the lid mirror 2 and the annular unit forming the two flanges 3, 4, are both made of a cardboard material. Suitable cardboard materials in this context are well known to those skilled in the art. As an example, it can be mentioned that the lid mirror 2 can be made of Stora Enso's Cupforma Special 270 g / mz with 13 g / m2 PE and that the annular unit can be made of spirally wound cardboard in three layers of Stora Enso's Cupforma Classic 230 g / m2 with a cover layer of paper MG 60 g / m2. It can be mentioned that the combination of having a relatively high upper end 4 and that this flange 4 is retracted towards the center point C of the locking element 2 provides the possibility of very good stacking properties where problems with lids rubbing against each other and getting stuck are avoided.

The invention is not limited to the embodiment described above but can be varied within what is defined by the appended claims.

For example, it is not necessary that the lid 1 be substantially rectangular or that the corners of the lid 1 be rounded in the manner shown. Other conceivable shapes of the lid are circular, oval or substantially square with more or less rounded corners.

It is also not necessary to arrange a rim 6 in the periphery of the curtain mirror 2.

The mirror can be attached in another way, e.g. with its edge against the annular unit.

As for the container to which the lid 1 is intended to be applied, this may be intended for food, but many other types of contents are also possible.

Furthermore, the container can be made of a material other than the lid 1, e.g. plastic.

The distance between the outer periphery of the upper flange and the intended center line may, at least over the distance where the lower flange of the first lid overlaps at least a part of the upper lid of the second lid even when stacked, be substantially equal to, and not necessarily less than, the distance between the lower inner the inner periphery of the river and the center line. That the distances can be substantially equal means that the distances can be equal or even that the distance between the outer periphery of the upper flange and the imaginary center line may be slightly longer than the distance between the inner periphery of the lower flange and the center line. One skilled in the art is aware that the lower end of the carton lid of the type described herein is somewhat resilient, which means that the principle of the invention also works in these cases, i.e. when one lid is placed completely loosely on another, the upper lid can remain in a position such that a vertical gap is formed between the lid mirror of the upper lid and the upper flange of the lower lid. However, due to the resilient properties of the lower flange, this gap disappears with a light pressure on the upper cover, e.g. then additional lids are placed on the stack, so that the lid mirror of the upper lid rests on the upper flange of the lower lid. Even when the gap is removed in this way, the lids can be easily removed from the stack one by one because the upper flange of the underlying lids prevents the lids from getting too close and sticking tightly together.

It is thus possible that, e.g. to save material, allow a small (initial) gap between the upper flange and the overlying lid mirror, which gap closes under load when the lower ns springs spring and the lids thus go into each other which movement is stopped by the lid mirrors landing on the underlying lid upper fl end without that the forces between the lower extremities have increased to such an extent that they cause problems in separation. In this case, the lower flange can also stand on the ledge while there is a gap between the upper lid and the next lid mirror, which closes when loaded so that the upper lid rests against the resilience of the upper upper and lower flange as it slides over the ledge does not give a locking effect which makes separation difficult .

Claims (8)

10 15 20 25 30 11 PATENT REQUIREMENTS A stackable cardboard lid (1, 1a, 1b, 1c, 1d), comprising - a substantially flat lid element (2) intended to cover an opening in a container when the lid (1) is applied to the container, said lid element (2) having a upper side (2a) and a lower side (2b) where the lower side (2b) is intended to face the container when applying the lid (1), - a lower flange (3) extending along the outer edge of the lid element (2) and at least partially downwards from the lower side (2b) of the lid element (2) to allow cooperation with the container when applying the lid (1), and - an upper flange (4) extending along the outer edge of the lid element (2) on the upper part of the lid element (2) side (2a), the lid (1) being arranged in such a way that the lower flange (3b) of a first lid (1b) overlaps at least a part of the upper flange (4c) of a second lid (1c) when the first and second lid ( 1b, 1c) are stacked on top of each other, characterized in that the distance between the outer periphery of the upper flange (4) and an imaginary center line through a center point (C) of the lid element (2) is, at least over the distance where the lower flange (3b) of the first lid (1b) overlaps at least a part of the upper flange (4c) of the second lid (1c) when stacked, substantially equal to or less than the distance between the inner periphery of the lower flange (3) and said center line in an arbitrary position the outer edge of the lid element (2). along Stackable cardboard lid (1) according to claim 1, characterized in - that the height of the upper ns end (4) over the upper side (2a) of the lid element (2) and the shape and extent of the lower flange (3) from the lower side (2) of the lid element (2) 2b) are adapted in such a way that the lower flange is not appreciably pressed against a corresponding lower end on an adjacent lid when stacking a plurality of lids. 10 15 20 25 30 12 Stackable cardboard lid (1) according to claim 1 or 2, characterized in that the lid (1) is provided with a ledge (9) which runs circumferentially outside the upper flange (4), the outer edge of the ledge (9) merging into the lower ns änsen (s). Stackable cardboard lid (1) according to one of the preceding claims, characterized in that the lower flange (3) is provided with a bulge (7) which runs circumferentially on the inside of the lower flange (3), which bulge (7) is intended for co-operation with an upper part of the container when the lid (1) is applied to the container. Stackable cardboard lid (1) according to any one of the preceding claims, characterized in that the lid (1) is built up of a first, flat unit and a second, annular unit, the first unit constituting the lid element (2) and the second unit constituting at least a part of both the lower and the upper flange (3, 4). Stackable cardboard lid (1) according to claim 5, characterized in that the first unit (2) is provided with a folded edge (6) along its outer edge, wherein an upper part (40) of the second unit is formed around and against said rim (6), the upper flange (4) being formed by the upper part (40) of the second element and said rim (6). Stackable cardboard lid (1) according to one of the preceding claims, characterized in that the upper flange (4) has a circumferential shape or a folded shape. Stackable cardboard lid (1) according to one of the preceding claims, characterized in that the upper flange (4) is substantially flat and extends substantially perpendicularly up from the upper side (2a) of the hockey element (2).