GB2260969A

GB2260969A - Tamper evident container

Info

Publication number: GB2260969A
Application number: GB9221873A
Authority: GB
Inventors: Paul T Rogers; Gerry V Steed
Original assignee: DRG Plastics Ltd
Current assignee: Rexam Plastic Containers Ltd
Priority date: 1991-10-17
Filing date: 1992-10-19
Publication date: 1993-05-05
Anticipated expiration: 2012-10-19
Also published as: GB9221873D0; GB2260969B

Abstract

A container body and lid, preferably injection-moulded from a tough plastics material e.g. polypropylene, having overlying tabs (44, 50) which are sealed together for secure closure. The overlying tabs have respective tear-lines (46, 48) in register, inwardly of the sealing. Each tear-line is defined by spaced nibs (70), the nibs of the overlying tabs being staggered so that tearing only involves one layer at a time. The nibs (70) are preferably of arrowhead shape. <IMAGE>

Description

Tamper-Evident Container The present invention relates to a tamper-evident container. It particularly relates to a container having a container body and a lid which can be sealed together in a manner such that it is clearly visibly apparent if the seal has subsequently been broken.

According to the invention, there is provided a plastics container comprising a container body having a mouth and at least one peripheral tab projecting outwardly adjacent the mouth the or each tab extending around only a minor proportion of the body; and a lid engageable with the body to close off the mouth, said lid also having one or more peripheral tabs such that the lid is locatable on the body to close the mouth with at least one lid tab overlying a body tab; said overlying tabs having apertured tear-lines which are in register and which extend across the tab to define removable portions.

In use, the overlying tabs are connected outwardly of the tear lines (e.g. by welding) so that the removable portions must be removed to permit removal of the lid.

Thus a tear-off portion is connected to the main part of the body or lid by a plurality of bridge portions which may be small nibs. Desirably the bridge portions of the lid and body are staggered. Thus tearing off a pair of overlying tabs does not involve tearing through two layers of plastics simultaneously. Desirably the container body and/or the lid (and preferably both) have/has a smooth outline which is disrupted by removal of a tab, which is thus readily evident. For example, the outline may be all flat or convex, with removal of a tab producing a concavity. Desirably the container is multi-sided, rather than circular, the arrangement of tabs being symmetrical such that a lid cannot be set on a body incorrectly, with the tabs not in register. Thus there may be a tab at each corner. Of course, curved non-circular shapes (e.g. ellipses) are also possible.

Preferably the container comprises polypropylene or other tough plastics material, e.g. a polyethylene.

Preferably (but not essentially) the lid and body are made by injection moulding. The manufacturing process may produce feed bars which serve as the bridge portions that provide the lines of weakness.

The lid and body portions may have complementary Usection peripheral flanges, one of which is receivable in the other on closing the container. The tabs may be adjacent or beyond the mouths of their respective channels so that neither their presence nor their absence affects the closeability of the container. One of the flanges may terminate in an edge which is snapengageable with a formation of the other flange. These snap-engagement formations may be absent in the corner regions.

Some embodiments of the invention will now be described in more detail with reference to the accompanying drawings in which: Figs 1 and 2 are plan and elevation views of a generally rectangular lidded plastics container embodying the invention; Fig 3 is an enlarged detail of a corner region of the lid, seen in plan; Fig 4a and 4b are vertical sectional views through a corner portion of a lid and a container body, respectively; Figs 5 and 6 are schematic vertical sections on V-V and VI-VI respectively in Fig 1; Fig 7 is a perspective view from above showing a detail of a corner region of a container body; and Figs. 8 and 9 are views corresponding to Figs 3 and 7 but showing a second embodiment.

The illustrated container is, in many respects, conventional. Thus there is a tub body 10 which is generally rectangular in form. It has a flat base 12 from which arises a peripheral wall 14 which has two opposed generally flat end wall portions 16 and two opposed, slightly curved, side wall portions 18. The cross-section increases slightly from the base 12 towards the mouth, where the wall portion 14 terminates in a flange. Over most of the periphery, this is as shown in Fig 5, having the form of an inverted "U", with a horizontal portion 20 leading to a short downward limb 22 that terminates with a downwardly facing edge 24. The lid 26 is also largely conventional, having a main web portion 28 and a peripheral flange 30, of inverted-U section.As shown in Fig 5, this has an inner upwardly extending wall portion 32, a roof portion 34, and an outer, downwardly extending, wall portion 36, terminating in a small outwardly directed flange 38. Inside the outer wall portion 36, there is an inwardly directed projection 40. It can be seen that the channel 30 of the lid is dimensioned to receive the channel at the top of the body wall 14 snugly, with its edge 24 snap-engaging behind the projection 40.

In the corner regions, however, the construction is somewhat different. As shown in figs 6 and 7, the outer flange 22 of the body (Fig. 5) is extended downwardly to form a support flange 41, dimensioned to extend downwardly beyond the outer wall portion 36 of the lid.

At its lower extremity, the support flange 41 has an outwardly turned lip portion 42 which is coupled to a horizontally extending tab 44 via a tear line 46, to be described later. The lid has, in the corner regions, a channel portion 30' which is much the same as over the rest of its extent. However, it lacks the internal projection 40 (Fig. 5) and the outward flange 38 (Fig. 5) is replaced by means defining a tear line 48, by which a tab 50 is connected. The tab 50 is shown more clearly in figs 3 and 4a. It is shaped and dimensioned so as to be suitable to afford a secure pinch-grip between a user's thumb and forefinger. There is a uniform, planar lower surface 54. The radially inner edge 56 is curved, to parallel the outer wall 57 of the lid flange 30'. The edge 56 and the flange wall 57 are slightly spaced, and connected by a plurality (here six) of spaced nibs 58.

As shown, each of these tapers outwardly so that it has a relatively large zone of connection 60 to the tab 50, and a relatively small zone of connection 62 to the lid flange 30'. The tab 44 and line of weakness 46 of the body are substantially the same, except that the tab 44 has a thicker main portion 64 and a peripheral thinner portion 66, the reduction of thickness being achieved by a step down 67 from the upper surface 68. Furthermore, its nibs 70 are arranged so as to be staggered relative to the nibs 58 of the lid tab 50, so that there are never two nibs 58,70 closely adjacent to each other. The two tabs 44,50 maybe of substantially the same shape and size or the lid tab can be a little larger, as shown. The arrangement is such that when the lid is engaged with the container, the pairs of tabs 44,50 are in mutually overlying relationship.They can then be sealed together, suitably ultrasonically. The sealing may be arranged to produce a pattern on at least the upper surface, as shown at 72 in Figs 1 and 3. This serves firstly to show the operator that this particular container has been sealed; secondly to indicate to the ultimate user that this is a grip portion; and, thirdly, to provide a non-slip gripping surface.

It can also be seen in Fig 1 that the lidded container has a substantially smooth, continuous outline when viewed in plan. To achieve this the lid (and optionally also the container) has a flange 74 (which is an extension of the flange 38) whose outward extent increases towards the corner regions so as to provide a line continuous with the outer line of the tabs. This serves two purposes. Firstly, it provides protection of the tabs, which would otherwise be more subject to glancing blows. Secondly, it ensures that, once a tab has been removed, this is highly evident, since the simple outline has been disrupted.

In the embodiment shown in Figs. 1-7, the tear lines 46,48 of the corner tabs are curved, following the general form of the associated lid or body. Figs 8 and 9 show a variant in which the tear lines 146,148 are straight, which may make tearing simpler. This embodiment is generally the same as that already described, except that in each corner region the lip portion of the body is enlarged to form a pair of wings 142 that define a straight edge from which the nibs 170 extend to a straight edge of the tab 144. Similarly the lid has pairs of flange wings 199.

The container (lid and body) is desirably made from a tough plastics material, such as polypropylene.

Polyethylene might also be used. Both the lid and the body can be formed by injection moulding. Another possibility would be thermoforming but this may be less preferred, since the formation of the lines of weakness would probably require a separate cutting step. If the container is made of a tough material, rather than brittle material such as polystyrene, the tabs will be quite secure, with negligible risk of accidental detachment. Indeed, the "lines of weakness" will be capable of repeated hinging whereas a polystyrene tab with a line of weakness would tend to shear off if flexed. The arrangement of staggered nibs means that it is nevertheless comparatively easy to tear off the tabs as a deliberate act.

The illustrated "arrowhead" nib shape, with the narrow end towards the body of the container, means that the nib tends to be torn away with the tab. This leaves virtually smooth surfaces on the container, which is desirable from a point of view of appearance and for not leaving jagged surfaces. On the other hand, it might be preferred to reverse the arrowheads so that nibs remained on the lid and/or body, so as to made it still more evident that a tab had been torn away.

The lid remains snap-engageable on the body even after the tabs have been removed.

Claims

1. A plastics container comprising a body having a mouth and at least one peripheral tab projecting outwardly adjacent the mouth, the or each tab extending around only a minor proportion of the body, and a lid engaged with the body to close off the mouth, said lid also having one or more peripheral tabs which overlie body tabs; each tab of the or each pair of mutually overlying tabs having an apertured tear-line which is in register with the tear-line of the overlying tab and which extends across the tab to define a removable portion; each removable portion being connected to the main part of the body or lid by a plurality of bridge portions; the arrangement being such that for the or each overlying pair of tabs, the bridge portions of the lid and body are staggered.

2. A container according to claim 1 wherein the container body and/or the lid have/has a smooth outline which is disrupted by removal of a tab, which is thus readily evident.

3. A container according to claim 2 wherein said outline is substantially all flat or convex, with removal of a tab producing a concavity.

4. A container according to any preceding claim wherein the container is non-circular, and the arrangement of tabs is symmetrical such that a lid cannot be set on a body incorrectly, with the tabs not in register.

5. A container according to any preceding claim wherein the container comprises polypropylene or polyethylene.

6. A container according to any preceding claim wherein the bridge portions are nibs which taper in the bridging direction so that tearing tends to break away substantially entire nibs.

7. A container according to claim 6 wherein the nibs taper from the tab towards the main part of the container.

8. A container according to claim 6 wherein the nibs taper from the main part of the container towards the tab.

9. A container according to any preceding claim wherein the lid and body portions have complementary Usection peripheral flanges, one of which is receivable in the other on closing the container; and the tabs are adjacent or beyond the mouths of their respective channels so that neither their presence nor their absence affects the closeability of the container.

10. A container according to claim 9 wherein one of the flanges terminates in an edge which is snapengageable with a formation of the other flange.

11. A container according to claim 10 wherein said engagement formations are absent in the corner regions.

12. A plastics container according to any preceding claim formed by moulding, the moulding process producing the bridge portions.

13. A plastics container substantially as herein described with reference to and as illustrated in the accompanying drawings.

14. A process for producing a container according to any preceding claim wherein the lid and body are made by moulding, the moulding process being arranged to produce feed bars which serve as the bridge portions that provide the lines of weakness.

15. A process according to claim 10 including a step of engaging a lid on a container body, with tabs in overlying relationship, and welding tabs together outwardly of their tear lines.

16. A process according to claim 11 wherein the welding process is arranged to produce a pattern on at least the lid tab.

17. A process for producing a container substantially as herein described with reference to the accompanying drawings.