AU693141B2

AU693141B2 - Tamper evident container

Info

Publication number: AU693141B2
Application number: AU11398/95A
Authority: AU
Inventors: Stan Jackson
Original assignee: PACIFIC WORLD PACKAGING AUSTRA
Current assignee: Alto Manufacturing Pty Ltd
Priority date: 1994-01-31
Filing date: 1995-01-25
Publication date: 1998-06-25
Anticipated expiration: 2015-01-25
Also published as: AU1139895A

Description

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r P/00/011 2a15/91 Regulation 3.2(2)

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT o oo (t uD ua r rir rr o gDOUBB [t

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O 'II Application Number: Lodged: te o r ac~ e r rr rrr i r Invention Title: TAMPER EVIDENT CONTAINER er Q The following statement is a full description of this invention, including the best method of performing it known to us i i TAMPER EVIDENT CONTAINER FIELD OF INVENTION The present invention relates to the field of containers, particularly containers which include tamper evident closures. The invention particularly has application to those containers which have a tear-away strip connecting the lid portion of the container to the base portion of the container.

BACKGROUND ART A problem has been identified by the present applicant in the use of tamper evident containers of the type that have a tear-away strip.

Figures la and lb show an example of the type of container referred to.

Figure la shows an example of a lid portion 1 and having a tear-away strip 2.

o Figure lb shows an example of a container base portion 3.

Proximate the upper edge 5 of the base portion, there is provided a recess 4 which is configured to correspondingly mate with the tear-away strip 2 15 when the container is in a sealed and unopened condition. In order to open the sealed container, a user takes a hold of tab 6 and tears the strip 2 away form the lid 1. This unlocks the lid portion from the recess 4.

It has been found that once the tamper evident strip 2 has been torn away from the container 3, there is substantially no means remaining on the container 20 base portion to hold the lid to the base portion of the container. This separation of the lid and base portions of the container allows unencumbered access to the contents of the container. However, in the event that the container is to be 4 04 closed once again, a problem exists with regard to the manner in which the lid is to be releasably held or attached to the base portion. Consideration must be given to the likely events of having the re-closed container moved, angled, or bumped. In such situations, it is desirable to alleviate the risk that the lid will separate from the container base portion and accordingly expose the contents of the container to possible contamination and/or spillage.

One proposal for solving the problem of re-sealing the container is exemplified in US 4,281,774 and US 5,299,702. This proposal utilises a "plugin" type lid which fits into the container base portion. However, this "plug-in" type arrangement is considered to suffer from a number of disadvantages, namely that they occupy space in the container below the brimful line. This is 1r' 2 considered undesirable as the lid can interfere with the container contents and it is also not desirable to have the lid occupy space in the container below the brimful line.

Another proposal for solving the problem of lid separation is to provide a protrusion on the upper edge of the container base, the protrusion extending outwardly of the container. A corresponding recess may or may not be provided in the inside edge in the lid to provide a corresponding mating engagement with the protrusion of the base. There are a number of examples of such prior art, such as ALI-A 64452/94 and AU-A 23721/92. However, it is considered that problems exist in the manufacture of containers with protrusions thereon, or at least manufacturing such containers cost effectively or at a relatively low cost.

The problems stem from the type of die used in the manufacture of the lid o and base portions of the container. Usually, injection moulding is used in the manufacture of a plastic lid and base portions. In order to mould the recess 4 which accommodates the tamper evident sealing strip 2, the die used in the injection moulding process is a split die. The split in the die is used to remove or S separate the base of the container from the die.

Referring to Figure 2, there is shown a representation of the die 11, the container base portion 5, the protrusion 7 and the split 8 in the die, it can be 20 seen that, in practice, when the die is split or opened along split 8, the protrusion 7 on the upper edge of the container will still engage the region 12 of the die.

This has been found to cause a great deal of difficulty as the container base portion cannot be removed from the die or without a great deal of force and/or without a substantial risk of damage to the newly moulded base or die.

Thus, it is desirable, particularly where there is a relatively high volume of containers and lids to be manufactured, to provide a protrusion on the outer extremity of the container base portion.

It is considered that the industry in general has to date either ignored or failed to provide a solution to the problem of the re-closing of tamper evident type containers. The general public have therefore had to endure the inconvenience of such containers and their susceptibility to allowing contamination of contents through, for example, spillage and/or lid removal.

3

OBJECTS

An object of the present invention is to provide a container that can retain a lid portion on the base portion after a primary locking means has been removed.

SUMMARY OF INVENTION The present invention is predicated on the realisation that a characteristic or quality of the materials used in the moulding of the container lid and base portions can be used to address one or more problems of the prior art.

In one aspect, the present invention provides an angled or inclined wall section of a container, preferably on the base portion, proximate the region or part(s) of the region where the container lid is to contact the base portion. The invention uses the characteristic of flexibility or rigidity of the container material.

o The angled or inclined walls may also be provided to facilitate an interference fit or seal between lid and base portion of the container. This characteristic is used in or proximate the portions of the container which contact together. The contact alleviates the requirement for a protrusion and the flexibility facilitates the removal of the container portions from the split die. In other words, the material rigidity can be utilized to allow sufficient retention of the lid on the base, however, the rigidity can also be utilized to facilitate removal from the die. The rigidity may be low enough or flexible enough to enable removal of the container from the die.

In a further aspect, the present invention provides a container having a base portion and lid portion, the container also having frangible tamper evident "o rmeans which provides a primary locking means to retain the lid portion to the base portion, the frangible tamper evident means being separably removable upon opening of the container, the container including an angled portion of the container, the angled portion having a generally planar surface, wherein upon reclosure of the container, an interference fit is provided between the lid portion and the base portion along at least a part of the planar surface so as to retain the lid portion to the base portion in the absence of the primary locking means. The interference fit or seal is of a nature as to substantially prevent contamination of container contents and/or to substantially prevent leakage or spillage of contents of the container, such as food, liquid or relatively small particles. The seal or fit is preferably over a substantial portion of the contact area between the angled rim RA435 and the lid.

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S .1 !L 4 a cavity into which material forming the article can be provided, the cavity having at least a first portion and a second portion in which respective first and second portions of the article can be moulded, the first and second portions being disposed at an angle to each other, such that, upon removal of the article from the cavity, the first portion of the article is flexed as it is withdrawn through the second portion of the cavity.

Another aspect of the present invention is also predicated on the principle of providing an interference fit between lid and base portions of a tamper evident container, in addition to the removable tamper evident seal strip.

The present invention provides a re-closable container having a lid portion and a base portion, the base portion having a diameter at an upper edge thereof such that an interference fit is created between the base and lid portions upon placement of the lid portion on the base portion.

0 The interference is preferably provided by inclined edge and/or o 15 configuring the upper edge portion of the container lid and/or base portion at an S angle to the vertical. The interference fit can in this way be enabled by distortion of the upper edge inwards of the container, thus creating tension between the .oo base and lid portions. The tension or interference can thus be used to hold the lid in a closed position relative to the base of the container.

0:.01 20 A preferred embodiment of the present invention will now be described with reference to the accompanying drawings, in which: Figures 1A and 1B show an example of a container lid and base portion to which the present invention applies; Figure 2 shows, in cross section, an example of one solution to the problem of lid re-closure, but whic' has been found to be less acceptable; and Figure 3 shows, in cross s ton, an example of the present invention as applied to a container base portion. The invention is equally applicable to a container lid portion.

With reference to Figure 3, there is an angled section 9 of container wall provided proximate the top of the base 5 of the container. The angled wall 9 is so called as it is inclined relative to the vertical axis in the exemplary container shown in the drawings. Numeral 10 serves to denote the angle.

The angled or inclined portion 9 can be made of a length, thickness and/or size cw would be sufficient to achieve an interference fit as is desired between the lid and base portions of the container. The inclined portion 9 may also be formed by a weakening of the container wall, whether the weakening is in the lid and/or base portions. The angled or inclined portion 9 may additionally and/or alternatively be provided on the lid portion similarly to achieve an interference fit. Where the angled portion 9 is additionally or singularly provided on the lid portion, the angled portion 9 may be provided in an inward direction, as opposed to the outwardly inclined portion 9 shown in Figure 3.

Use of the present invention therefore enables a tamper evident seal to be removed from the recess 4 and thus allowing access to the contents of the container. When it is desired to close the container again, the lid or cover o 0portion can be placed back on the container. The lid portion can then be held in S° its relative juxtaposition to the container as provided for by the present invention.

S 15 In respect of the die, referring to Figure 3, there is illustrated a die with at least one cavity 13. The cavity 13 is formed of at least two portions 14, 15 In 0 moulding the article, material is injected into the cavity. In removing the article from the die, the die is opened at split 8 and the article is withdrawn, the angled or weakened portion of the base (or lid) is flexed or bent to pass through cavity S 20 portion 14 and out of the mould.

The disclosure of the present invention is intended to make reference to a lid portion of the container without limitation. That is, the container may have a o lid, cover, bung or other suitable closure, without departing from the spirit of the invention.

Within the scope of the present invention, there is encompassed many possible variations. In particular, it should be kept in mind that the angled portion of the present invention is provided in such a manner as to create an interference fit between parts of a container so as to allow re-closure of the container after a tamper evident seal has been removed, and is provided in a manner that enables moulding of the container or its component parts and relatively improved removal of the mould container or its component parts from the mould.

Claims

1. A container having a base portion and a lid portion, said lid portion Shaving: ia first portion; a skirt portion dependent from said first portion, and being adapted to co- operate with the base portion to provide a primary locking means; at least a part of said skirt portion being a frangible tamper evident means, said frangible means being at least partially separable from the lid portion in order to open the container and to destroy said primary locking means; said base portion having: a first end and a second end, said second end terminating at a topmost *"Oo0 edge of the base portion and being adapted to co-operate with said skirt portion; an inner surface and an outer surface; an upper portion of the second end of the base portion extending from the topmost edge of the base portion at least partially towards said first end, said upper portion having a substantially planar outer surface and being outwardly inclined such that the diameter of a top end of the inclined upper portion, being the topmost edge of the base portion, is greater that the diameter of a lower end of the inclined upper portion; the diameter of the skirt portion being less than or equal to the diameter of the top end of the inclined upper portion, such that an interference fit is provided between the lid portion and the base portion along at least a part of the said planar outer surface'so as to retain said lid portion on said base portion, in the absence of said primary locking means.

2. A container according to claim 1 wherein the inclined upper portion is a flexible portion of the container.

3. A container according to any one of claims 1 or 2 wherein the interference fit is provided only on the planar surface.

4. A container according to any one of claims 1 to 3 wherein the inclined Suppe" portion is an angled wall. y~ I7 A container as claimed in c!r. bstantially as herein described with reference to Figures 1A, IB and 3.

6. A die used in the manufacture of a container as claimed in claim 1, said die including: a cavity into which material forming the article can be provided, the cavity having at least a first portion and a second portion in which respective first and second portions of the article can be moulded, the first and second portions being disposed at an angle to each other, such that, upon removal of the article from the cavity, the first portion of the article is flexed as it is withdrawn through the second portion of the cavity.

7. A die as claimed in claim 6 substantially as herein described with reference to Figure 3. o 44 DATED this 12th day ct January, 1998. o0 PACIFIC WORLD PACKAGING (AUSTRALIA) PTY. LTD. t WATERMARK PATENT TRADEMARK ATTORNEYS 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA RCTS:SMM:ML (DOC 46) AU1139895.WPC r l nf- ;-L I" I o D- ~l, 0 0I 0 *00 C.# 0 ABSTRACT The present invention relates to tamper evident containers. The invention addresses the problem of re-closing or fitting the lid portion to the base portion of the container once the tamper evident strip has been removed. The invention provides an angled rim and facilitates an interference fi, between the lid and base portions. Also, the invention relates to the die and process of manufacture used to make an article. *or 4 i, #0 0n 1