EP0251418A1

EP0251418A1 - Reclosable pack comprising a container and a lid fitting on the container

Info

Publication number: EP0251418A1
Application number: EP87201271A
Authority: EP
Inventors: Jan Dierdorp
Original assignee: Wavin BV
Current assignee: Wavin BV
Priority date: 1986-07-04
Filing date: 1987-07-02
Publication date: 1988-01-07
Also published as: NL8601752A

Abstract

A reclosable pack comprises a container (1) and a lid (2) fitting on the container. The lid has an edge part (3) for fixing the lid on the container, a middle part (4), and an intermediate part (5) connecting the middle part to the edge part. The edge part (3) at least consists of an essentially radially extending flange (6) which is welded onto an also radially extending top edge part (7) of the container (1) by means of a removable weld connection part (9) which connects to said flange (6) and fits into the opening of the container bounded by the top edge (10). The part (9) of the edge part (3) of the lid (2) which connects to the flange (6) of the lid is essentially cylindrical. this cylindrical part (9) at the underside is bounded by a slightly outward-projecting peripheral edge (11). The peripheral edge (11) is interrupted at a number of places.

Description

The invention relates to a reclosable pack comprising a container and a lid fitting on the container, said lid having an edge part for fixing the lid on the container, a middle part, and an intermediate part connecting the middle part to the edge part, the edge part at least consisting of an essentially radially extending flange which is welded onto an also radially extending top edge part of the container by means of a removable weld connection, and part which connects to said flange and fits into the opening of the container bounded by the top edge.
Such a pack is known from NL-A-7901442.
In this known pack the part of the edge part of the lid which connects to the flange is conically shaped with an increasing diameter in the direction from the flange. The conically shaped part at the underside merges into a radially extending part of the intermediate part of the lid via an arcuate transition part. The conically shaped part lies against the inside wall of the container near the top edge. The known pack has a number of disadvantages. When the lid is formed by thermoforming removal of the lid from the mould is very difficult as the conically shaped part of the lid which connects to the flange has an anti-releasing shape while said part is very rigid in radial direction. Furthermore, due to the rigidity of the lid in radial direction the inside diameter of the wall part of the container which co-operates with the lid must be accurately adapted to the maximum outside diameter of the conical part of the edge part of the lid. Otherwise, either the forces for replacing the lid on the container or removing it therefrom will be to great or the lid does not fit properly on the container. Finally, when placing the lid on the container or removing it therefrom air cannot escape between the lid and the inside wall of the container.
The object of the invention is to provide a pack which does not have the above mentioned disadvantages.
This object is achieved by a pack of the the abovementioned type which is characterized in that the part of the edge part of the lid which connects to the flange of the lid is essentially cylindrical, the cylindrical part of the edge part at the underside is bounded by a slightly outwardprojecting peripheral edge, and the peripheral edge is interrupted at a number of places.
Through these measures it will be much easier to remove the lid from the mould after it has been formed by thermoforming, as the cylindrical part of the edge part of the lid is deformable in radial direction. The lid can be removed from the container and replaced again easily, while the projecting peripheral edge lies relatively tightly against the inside wall of the container, thereby ensuring that the pack is well sealed also after reclosing. The interruptions in the edge let air through during removal of the lid from the container and closing of the pack. Moreover, the required closing power of the lid can be influenced through selection of the number of interruptions.
Further characteristics of the pack are contained in the remaining sub-claims.
The invention also relates to a lid for a reclosable pack according to the invention.
The invention will now be explained with reference to the description of an embodiment shown in the drawing, in which:

Fig. 1 shows a pack according to the invention, partially in cross section and partially in side view;
Fig. 2 shows a cross section on an enlarged scale of part of the closed pack near the top edge;
Fig. 3 shows a lid according to the invention partially in cross section and partially in side view;
Fig. 4 is a top view of the lid of Fig.3;
Fig. 5 is an illustration on an enlarged scale of detail V in fig.3;
Fig. 6 is a cross section along line VI-VI in Fig. 5;
Fig. 7 is a partial cross section on an enlarged scale of another embodiment of the lid according to the invention;
Fig. 8 is the same cross section as that of Fig. 7 of yet another embodiment of the lid according to the invention; and
Fig. 9 shows a number of lids according to the invention stacked on top of each other.

The reclosable pack shown in Figs. 1 and 2 comprises a container 1 and a lid 2 which fits on the container. The lid 2 has an edge part 3 for fixing the lid 2 on the container 1, and a middle part 4 and intermediate part 5 which connects the middle part 4 and the edge part 3. The edge part 3 consists at least of an essentially radially extending flange 6 which is welded onto an also radially extending top edge part 7 of the container 1 by means of a weld 8 which is designed as a peel-off weld, and an essentially cylindrical part 9 which connects to the flange 6 and fits into the opening of the container 1 bounded by the top edge 10. The flange 6 thereby merges with an essentially uniform wall thickness into the cylindrical part 9.
This design gives a very well sealed pack which is particularly suitable for perishable products, said pack being relatively easy to open without damage to the lid, while after opening the pack can be reclosed with the lid, which takes up the same position as it had in the originally closed pack, so that the chance of smearing of the product when reclosing the pack is extremely slight.
The cylindrical part 8 is bounded on the underside by a slightly outward-projecting peripheral edge 11 with a height of, for example, 0.6 mm. This peripheral edge can be interrupted at several (for example, three) places, as shown in Figs. 3, 5 and 6.
The edge 11 ensures good closure of the pack, even after opening and reclosing, through the slight countertaper of the top edge 10 of the container (Fig. 1) or the groove 11a which is provided at the level of the peripheral edge 11 in the top edge 10 (Fig. 2). The interruptions 12 of the edge 11 have two functions: letting through air during opening and reclosing of the pack, so that removal and refitting of the lid are facilitated, and influencing the required closing power through the number of interruptions and the size thereof.
The middle part 4 of the lid 2 is essentially flat and is in or close below the plane of the flange 2 of the lid. This flat middle part 4 is connected by means of a rounded part to a cylindrical, or preferably countertapering, conical part 12, which merges (again via a rounded part) into a highly tapering or even flat part 13.
The intermediate part 5 of the lid 2 has an essentially U-shaped cross section. The top part of the inside wall of the intermediate part consists of the above-mentioned parts 12 and 13. The intermediate part 5 also has an essentially flat bottom 14 to which an upright bottom outside wall part 15 and an upright bottom inside wall part 16 connect, which in turn connect at the top side to the outward-projecting peripheral edge 11 and the inside wall part 13. Near the projecting peripheral edge 11 of the lid the diameter of the bottom outside wall part 15 is smaller than the diameter of the cylindrical part 9.
The lid is also provided with a lip 17 connecting to the flange 6 (see Fig. 4), by means of which opening of the pack (for the first time, and after reclosure) is simplified. Centring of the lids (print all in the same position) is thereby simplified.
Fig. 7 shows an embodiment of a lid according to the invention in which the middle part 4 is in the same plane as the flange 6. The part 12 of the lid which connects to the middle part 4 is essentially cylindrical.
In the embodiment of the lid according to Fig. 8 the middle part 4 is below the plane of the flange 6. The part 12 connecting to the middle part is conical and counter-tapering.
Fig. 9 shows a number of stacked lids in the embodiment of Fig. 2. The middle part 4 of the lid lies close below the plane of the flange 6, and the part 12 connecting to the middle part is conical and counter-tapering. The part 13 connecting to the part 12 extends essentially in the radial direction.
In all embodiments of the lid according to the invention the upright parts 15 and 16 of the intermediate part 5 are conical and tapering. This is advantageous for stacking and unstacking the lids (see Fig. 9). The intermediate part 5 has a guiding, locating form.
The bounding of the bottom upright parts 15 and 16 by the peripheral edge 11 and the tapering, highly conical or even redially extending part 13 determines the nesting depth of the lids on each other. Since the bounding exists on the inside and on the outside, the nesting depth is well defined, even if there are forces or movements which press the stack of lids at an angle. Thanks to this good definition of the nest depth, the distance between the flanges 6 of the lids 2 is fixed, which is of great importance for working on filling machines.
The conical counter-tapering nature of the part 12 connecting to the middle part 4 of the lid has the advantage that a large printable face is obtained on the middle part 4 and that supporting of the lid 2 in the stack takes place on a large face, while the centring of the lids relative to each other is improved.
The transitions between the different parts of the lids are rounded off, which is an advantage for the production, since such rounding off prevents notch effect during forming.
The central part 4 of the lid is much higher up than the bottom 14 of the intermediate part 5 of the lid, as can be seen from the figures. This means that the enclosed volume of the pack is relatively great, which is advantageous during filling, due to the fact that the pack can have a higher degree of filling.
Placing the middle part 4 of the lid below the plane of the flange 6 means that the pack can be centred to some extent in the stacked state, while on the other hand a large enclosed volume is achieved for the pack. Raising of the middle part 4 of the lid also means that a certain amount of space is present between the packed product and the lid, as a result of which discoloration of the product through contact with the lid is avoided.

Claims

1. Reclosable pack comprising a container (1) and a lid (2) fitting on the container, said lid having an edge part (3) for fixing the lid on the container, a middle part (4), and an intermediate part (5) connecting the middle part to the edge part, the edge part (3) at least consisting of an essentially radially extending flange (6) which is welded onto an also radially extending top edge part (7) of the container (11) by means of a removable weld connection, and part (9) which connects to said flange (6) and fits into the opening of the container bounded by the top edge (10), characterized in that the part (9) of the edge part (3) of the lid (2) which connects to the flange (6) of the lid is essentially cylindrical, the cylindrical part (9) of the edge part (3) at the underside is bounded by a slightly outward-projecting peripheral edge (11), and the peripheral edge (11) is interrupted at a number of places.

2. Pack according to Claim 1, characterized in that the weld (8) between the flange (6) of the lid (2) and the top edge part (7) of the container (1) is designed as a peel-off weld.

3. Pack according to Claim 1 or 2, characterized in that the flange (6) of the lid merges with an essentially uniform or flowing wall thickness into the cylindrical part (9) of the edge part (3) of the lid.

4. Pack according to one of Claims 1 to 3, characterized in that when the pack is closed the peripheral edge (11) of the lid falls into a peripheral groove (11a) in the top edge (10) of the container.

5. Pack according to one of Claims 1 to 4, characterized in that the middle part (4) of the lid is essentially flat and is located in or close below the plane of the flange (6) of the lid.

6. Pack according to one of Claims 1 to 5, characterized in that the intermediate part (5) of the lid has an essentially U-shaped cross section, and the top part (12) of the inside wall of the intermediate part (5) which connects to the middle part (4) of the lid is cylindrical or, preferably, has a diameter which increases in the direction of the middle part (4).

7. Pack according to Claim 6, characterized in that the top part (12) of the inside wall of the intermediate part (5) at the underside merges into a middle wall part (13) with a relatively greatly increasing diameter in the direction from the middle part (4) of the lid.

8. Pack according to one of Claim 1 to 7, characterized in that the U-shaped intermediate part (5) has an essentially flat bottom (14) to which an upright bottom outside wall part (15) and upright bottom inside wall part (16) connect, which in turn connect at the top side to the outward-projecting peripheral edge (11) of the edge part (3) of the lid and the middle inside wall part (13) respectively.

9. Pack according to Claim 8, characterized in that near the projecting peripheral edge (11) of the edge part (3) of the lid the diameter of the bottom outside wall part (15) of the intermediate part (5) is smaller than the diameter of the cylindrical part (9) of the edge part (3).

10. Lid for a reclosable pack according to one or more of the preceding Claims 1-9.