GB2211830A

GB2211830A - A tamper-indicating cap for closing a container

Info

Publication number: GB2211830A
Application number: GB8815051A
Authority: GB
Inventors: Manetti Guido
Original assignee: PLASTITALIA Srl
Current assignee: PLASTITALIA Srl
Priority date: 1987-11-04
Filing date: 1988-06-24
Publication date: 1989-07-12
Anticipated expiration: 2008-06-24
Also published as: BE1001840A6; ES1007968U; ES1007968Y; IT8711786V0; IT212946Z2; FR2622722A3; NL8801884A; DE8807103U1; GB8815051D0; GB2211830B; FR2622722B3

Abstract

A tamper-indicating cap 1 for a container, such as a beer keg, comprises a disk 2 and a depending rim 3. Inwardly projecting teeth 5, 7, 9 are spaced around the rim 3 for cooperation with a flange on the neck of the container to be closed. A tab 10 is delineated by a fracture line 12 and is divided into two parts 10A and 10B by a foldline 20. The cap is of thermoplastics material and is warmed before application to the container, thereby expanding it so as to fit over the flange, which it then contracts around on cooling. To open the container, the tab part 10A is pressed inwardly. It breaks around the fracture line 12 and folds about the foldline 20. A finger can then be inserted to pull the tab 10 and break the remainder of the fracture line 12. The cap can then be removed completely by flexure. <IMAGE>

Description

TITLE A cap for closing a container DESCRIPTION The invention relates to a cap for closing a container having a neck with a peripheral flange.

The invention provides a cap for closing a container having a neck with a peripheral flange, the cap being formed from a thermoplastics resin and comprising a disk, a peripheral rim depending from the disk, a plurality of inwardly extending projections spaced around the rim for engagement in use with the flange, and a tab formed in the disk and the rim and defined by a fracture line extending to two points on the edge of the rim, each point being between two of the projections.

The cap of the invention is primarily intended for sealing large containers, for example of from 30 to 50 litres capacity, and particularly beer kegs. Other uses may, however, be envisaged. As will be described hereinunder, the cap of the invention may be removed from the container by first opening the seal provided by the tab, and then flexing the cap. Without opening the seal, however, the cap cannot be removed from the container, once applied, except destructively. The cap is therefore tamper-proof, providing a visual indication of unauthorised opening of the container. Such a guarantee seal is particularly important for containers of material for human comsumption, such as beer kegs.

Preferably there are three inwardly extending projections equispaced around the rim, with the fracture line extending to points on the edge of the rim between the same two adjacent ones of the projections. The tab may extend over the centre of the disk and be provided with a foldline dividing it into two parts for reasons discussed hereinbelow. The fracture line is suitably formed by discontinuous partial incisions in the material of the disk. The projections may be of saw toothed section and have rounded ends to assist in the fitting of the cap to the container as discussed hereinbelow.

The invention is illustrated by the drawings, of which: Figure 1 is a bottom plan view of a cap according to the invention; Figure 2 is an elevation of the cap of Figure 1, taken along the line II-II in Figure 1; Figure 3 is a top plan view of the cap of Figure 1, but showing the tab partially removed; Figure 4 is an elevation of the cap of Figure 1, taken along the III-III in Figure 3, but showing the tab wholly removed; Figure 5 is a perspective view of the cap of Figure 1; and Figure 6 is also a perspective view of the cap of Figure 1, similar to Figure 5 but showing the tab partially removed.

Referring to the drawings, a cap 1 formed from a thermoplastics resin comprises a disk 2, a peripheral rim 3 depending from the disk 2, three inwardly extending projections or teeth 5, 7 and 9 equispaced around the rim 3 and a tab 10 defined by a fracture line 12. The disk 2 may have a raised central part, here shown as 2A, but this is not essential. The fracture line 12 extends to two points 14, 15 on the edge of the rim 3 symmetrically located between the adjacent teeth 7 and 9, and is formed by partial incisions 16 in the material from which the cap 1 is formed. These partial incisions 16 are shown as discontinuous, being separated by short unincised sections 16A, but could if desired by replaced by a single continuous partial incision. The fracture line 12 may extend into the material of the rim 3 as shown by the weakened or partially incised portion 18 of the rim 3.The tab 10 extends over the centre of the cap 1, facing the tooth 5. It is divided into two sections 10A and lOB by a plastic hinge or foldline 20.

To apply the cap 1 to the neck of a container, which neck is provided with a peripheral flange, the cap 1 is first heated. The thermoplastics material softens slightly and expands so that the teeth 5, 7 and 9 can pass over the flange on the container neck. Contraction of the material on cooling then causes the cap to fit securely around the neck with the teeth 5, 7 and 9 beneath the flange. To assist in the application of the cap 1 to the container neck, the teeth 5, 7 and 9 may be saw-toothed in section and have rounded ends.

To open the container, once the cap 1 is applied, the section 10A of the tab 10 is pressed inwardly. The material of the disk 2 breaks along the part of the fracture line 12 surrounding the section 10A. The section 10A then folds inwardly around the foldline 20. A finger can now be inserted and the tab 10 pulled to break it off along the remainder of the fracture line 12. Once the tab 10 is removed, the remainder of the cap 1 can be removed, if desired, by flexing it.

Unless the tab 10 is removed as described in the last preceding paragraph, the cap 1 cannot be removed except destructively. The cap 1 cannot therefore be removed as a whole and subsequently replaced, so it provides a tamper-proof guarantee seal for the container.

Claims

1. A cap for closing a container having a neck with a peripheral flange, the cap being formed from a thermoplastics resin and comprising a disk, a peripheral rim depending from the disk, a plurality of inwardly extending projections spaced around the rim for engagement in use with the flange, and a tab formed in the disk and the rim and defined by a fracture line extending to two points on the edge of the rim, each point being between two of the projections.

2. A cap according to claim 1 in which there are three inwardly extending projections equispaced around the rim.

3. A cap according to claim 1 or claim 2 in which the two points on the edge of the rim to which the fracture line extends are between the same two adjacent ones of the projections.

4. A cap according to any proceding claim in which the tab extends over the centre of the disk.

5. A cap according to any preceding claim in which there is a foldline in the tab dividing it into two parts, one formed in the disk and one formed partly in the disk and partly in the rim.

6. A cap according to any preceding claim in which the fracture line is formed by discontinuous partial incisions in the material of the disk.

7. A cap according to any preceding claim in which the inwardly extending projections are of saw-toothed section.

8. A cap according to any preceding claim in which the ends of the inwardly extending projections are rounded.

9. A cap substantially as described herein with reference to the drawings.