GB2108465A - Container sealing - Google Patents

Abstract

A method of sealing a container 1 containing foodstuffs comprises forming a container 1 having a retaining lip 2 at its mouth, inserting the container 1 into a peripherally recessed hole 7 in a collar 6 so that the collar 6 abuts the retaining lip 2 and sealing a cover sheet 12 to a planar surface of the collar 6. Preferably four containers are retained as an assembly by integral cover sheets and integral collars which are separable along perforate lines 5, 11 to permit removal of a respective container with its collar and cover sheet from the remainder of the assembly. The cover sheets and collars are preferably of card 3, 10 coated with a plastics material 4 so that they may be heat sealed to each other. <IMAGE>

Description

SPECIFICATION Container sealing This invention relates to a method of sealing containers.

One known method for the production of sealed containers containing foodstuffs such as yoghurt involves heat shaping a continuous strip of plastics material to produce successive pot-shaped containers with integral planar flanges around the mouths thereof. Such containers are filled and then sealed by securing sheet material in face-to-face contact with said fianges.

With this known method, however, problems may arise with regard to achieving accurate registration of the closure sheets with the container flanges.

Also, the method may not be well-suited to the production of assemblies of containers having different contents.

An object of the present invention is to provide a simple and convenient method of achieving accurate sealing of containers which method is particularly suited to use in the context of assemblies of containers having different contents.

According to the invention therefore there is provided a method of sealing a container comprising the steps of locating a collar around the mouth of the container, which collar is formed separately to said container and has an upwardly directed planar surface thereto, and then applying a closure sheet over the mouth of the container and the said planar surface and fixing said sheet to said surface thereby to seal the container.

With this method due to the fact that the collar is formed separately from the container it will be appreciated that the collar can be readily constructed such as to facilitate assembly and accurate sealing of multiple, differently-filled containers. Thus, for example, the collar may be formed integrally with a plurality of like collars and, if desired, separation lines defined by perforations or other lines of weakness may be provided between such integral collars. Correspondingly, multiple said closure sheets may be formed integrally and separated by lines of weakness.

Most preferably the or each collar comprises a planar structure, such as a thin sheet of card, having a hole therein to receive the respective container.

Further, the periphery of the hole may be recessed slightly to receive a retaining lip of the container and thereby facilitate even fitting of the closure sheet.

The or each said closure sheet may also comprise a thin sheet of card and this may be coated with a plastics material, like the said planar collar surface, so that said fixing of the closure sheet to the collar can be effected by a heat-sealing process.

In a particularly preferred embodiment, four collars are formed integrally in square formation to permit corresponding assembly of four containers, the closure sheets for the respective collars being likewise united in square formation. A hole may be provided in the centre of the united collars and at a corresponding position in the centre of the united closure sheets to facilitate carrying of the assembly.

The invention will now be described further by way of example only and with reference to the accompanying drawings in which: Figure t is an exploded perspective view showing one container and closure sheets and collars suitable for use in performing the method of the invention; Figure2 is a sectional view of an assembly constructed from the components shown in Figure 1.

Figure 1 shows a vacuum-formed plastics container 1 generally of frusto-conical form, such container being closed at its smaller diameter bottom end and having an outwardly turned lip 2 around the periphery of its open larger diameter top end. The upper surface of the lip 2 lies in a plane at right angles to the axis of the container.

Figure 1 also shows a sheet 3 of thin card which is of square shape except for the corners which are cut off diagonally for ease of separation of the top sheet 10. The sheet 3 has a top surface 4 which is coated with a thin skin of plastics material. The sheet 3 is divided by perforation lines 5 into four equal approximately square collar sections 6 each of which has a large central circular hole 7 cut out of same. The four holes 7 are of a common diameter approximately equal to the outer diameter of the container 1 immediately below the lip 2. A small circular hole 8 is provided in the centre of the sheet. Around the periphery of the four large holes 7 there is a narrow annular section 9 which is recessed by displacement thereof downwardly.

The top sheet 10 shown in Figure 1 is identical with the sheet 3 except for the omission of the four holes 7, the recessed sections 9, and the cut off corners 14.

Also the sheet 10 is provided with a plastics skin on the bottom surface. Thus, the sheet 10 is divided by perforation lines 11 into four cover sections 12 and a central hole 13 is provided.

In use, four containers, of like form to the container 1 shown in Figure 1 are inserted into the holes 7 of the sheet 3 so that the lips 2 of the containers rest on the recessed sections 9 as shown in Figure 2. The four containers 1 are filled, if desired, with different contents (e.g. differently-flavoured yogurts.) The top sheet 10 is then positioned in superimposed relationship with the sheet 3 and is fixed in position by application of heat thereto, it being understood that such application of heat causes the confronting plastic skins of the sheets 3, 10 to become bonded to each other. As mentioned, the lips 2 fit in the recessed sections 9 and this facilitates smooth contact of the two sheets.

The upper surface of the top sheet 10 can be appropriately printed and decorated as desired.

The resulting assembly can be picked up and carried by insertion of a person's finger through the aligned holes 8, 13. When desired, an individual container 1 can be separated from the assembly together with the associated collar and cover sections 6, 12 of the two sheets 3, 10 by tearing along the pertaining perforation lines 5, 1 1 . Subsequently, the container can be unsealed by pulling away the top cover sheet 12 at the corner thereof overlying the severed corner 14 of the collar section 6.

With the arrangement so far described it will be appreciated that an assembly of four sealed contain ers having different contents can be manufactured in a particularly simple and convenient manner.

Moreover, the sheets can be readily aligned prior to heat-sealing of same and accordingly registration of the perforation lines can be reliably achieved.

It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only.

Claims (21)

1. A method of sealing a container comprising the steps of locating a collar around the mouth of a container, which collar is formed separately from said container and has an upwardly directed planar surface thereto, and then applying a closure sheet over the mouth of the container and said planar surface and fixing said sheet to said planar surface thereby to seal the container.

2. A method according to claim 1 wherein said collar is formed integrally with a plurality of like collars and subsequently separated therefrom.

3. A method according to claim 2 wherein lines of weakness are formed between adjacent said integrally formed collars.

4. A method according to claim 3 wherein said lines of weakness are formed by perforations.

5. A method according to any one of claims 1 to 4 wherein said closure sheet is formed integrally with a plurality of like closure sheets and subsequently separated therefrom.

6. A method according to claim 5 wherein lines of weakness are formed between adjacent said integrally formed closure sheets.

7. A method according to claim 6 wherein said lines of weakness are formed by perforations.

8. A method according to any one of claims 1 to 7 wherein the or each collar is formed as a planar structure having a hole therein to receive the or a respective container.

9. A method according to claim 8 wherein the or each container is formed having a retaining lip thereto and the hole in the or each collar is formed having a recessed periphery to receive the or the respective retaining lip.

10. A method according to any one of claims 1 to 9 wherein the or each closure sheet is coated with a plastics material.

11. A method according to claim 10 wherein the or each closure sheet is fixed to the or the respective collar planar surface by a heat-sealing process.

12. A method according to claim 1 wherein four collars are formed integrally. as a first sheet in a substantially square formation and four closure sheets are formed integrally as a second sheet in a like formation.

13. A method according to claim 12 wherein said first sheet is of substantially square planform having the four corners thereof removed.

14. A method according to claim 12 or claim 13 wherein a hole is formed centrally of said first sheet formation of collars and centrally of said second sheet formation of closure sheets.

15. A method according to any one of claims 1 to 14 wherein the or each closure sheet has informative matter printed thereon.

16. A method of sealing containers substantially as hereinbefore described with reference to and as illustrated in Figure 1 of the accompanying drawing.

17. Asealed containerformed buy a method according to any one of claims 1 to 15.

18. A sealed container according to claim 16 wherein said container is formed of a plastics material.

19. A sealed container according to claim 6 wherein said container is vacuum formed.

20. A sealed container according to any one of claims 16 to 19 wherein said container is of frustoconical shape.

21. A sealed container substantially as hereinbefore described with reference to and as iilustrated in Figure 2 of the accompanying drawing.