NZ528618A - Tamper evident container - Google Patents

Abstract

A tamper evident container including a base member and a co- operating lid or closure therefore, said lid being resiliently snap-fitting on said base member by having one or more formations thereon adapted to engage one or more co- operating formations of said base member, and additionally at least one section of said lid and said base member being initially secured to an abutting part of the other one of said lid and said base member, whereby when said lid is first removed from the base member the or each said section of said one of said lid and said base member is detached from said one and remains secured to the other of said lid and said base member, thereby to provide evidence to a user of opening of said container.

Description

1 5286)8 PATENTS FORM NO. 5 Patents Act 1953 Priority Details: No. 2002952090 Date: October 16,2002 COMPLETE SPECIFICATION Tamper Evident Container INTELLECTUAL PROPERTY OFFICE OF N.Z. - 3 OCT 2003 RECEIVED WE, Huhtamaki Australia Limited, an Australian company of P.O Box 490, Bankstown, New South Wales 1885, Australia, hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: P113BNZ/0202 1 a, TAMPER EVIDENT CONTAINER FIELD OF THE INVENTION This invention concerns containers such as are used for foodstuffs and the like, and in particular containers which are tamper evident.

BACKGROUND It is well known for manufacturers to supply their products to the market in containers consisting of a base member which contains the product and a lid which, after sale to a customer, can be detached from the base member and thereafter replaced on it. For example, dairy products such as ice cream, yoghurt 10 and butter, similar products such as margarine, iced confections and various other foodstuffs are often sold in tubs with such detachable lids. However, such containers are by no means limited to foodstuffs. Products such as adhesives, fillers and the like are also often sold in such lidded containers.

A problem which has accompanied the growth of self service sales outlets 15 is that of tampering with such containers. Customers wish to know, when buying a product such as those mentioned above, that the container has not been opened or otherwise tampered with. It is known for persons to open containers and remove parts of the contents or to contaminate the contents. Opening may also cause spoilage of perishable products. One response to this has been to 20 develop "tamper evident" containers which are unable to be opened without the fact of opening being apparent thereafter. Thus a customer, seeing that a container has been opened or tampered with, will be alerted to the fact that the contents may have been contaminated, spoiled or removed wholly or partially.

Very many types of tamper-evident containers or container closures have 25 been developed. These include containers in which the lid must be pried off a rim of a base member, but where access to an edge of the lid for prying is prevented by a formation on the base member which must be damaged or removed to enable such access. It is known also to provide foil or plastics seals on base members such as tubs or bottles which lie under the lid and must be damaged or 30 removed for access to be gained to the contents. Yet another approach is to provide containers with a "shrink wrap" plastics sheath which covers at least a part of both a lid and a base member of the container, and must be removed before the lid can be removed.

Tamper-evidence carries a cost, and many products are still sold in containers which are not tamper evident. For example, margarine, dairy-based spreads and the like are often sold in lidded tubs formed from plastics materials by injection moulding, thermoforming from plastic sheets, blow moulding and the 5 like, which are not tamper evident. The present invention is particularly directed to such containers, where low cost is particularly important. In certain aspects set out below, the invention lends itself to the production of containers from material of thickness greater than normal where welding-type methods are to be used for initial closure.

SUMMARY OF THE INVENTION The invention provides in a first aspect a tamper evident container including a base member and a co-operating lid or closure therefor, said lid being resiliently snap-fitting on said base member by having one or more formations thereon adapted to engage one or more co-operating formations 15 of said base member, and additionally at least one section of one of said lid and said base member being initially secured to an abutting part of the other one of said lid and said base member, whereby when said lid is first removed from the base member the or each 20 said section of said one of said lid and said base member is detached from said one and remains secured to the other of said lid and said base member, thereby to provide evidence to a user of opening of said container.

Preferably, after said first removal of said lid from said base member, said lid is replaceable on said base member with said one or more formations of said 25 lid engaging said one or more formations of said base member. That is, the lid and base member are initially secured together (after placement of a product in the base member), the said sections of lid or base member being broken away as the lid is first removed from the base member to provide tamper evidence, and the lid is thereafter replaceable on the base member in conventional fashion and 30 snap-fittingly retained.

The or a said formation on said lid may face inward and engages a peripheral rim formation on said base member.

In a preferred arrangement, the or each said section of said one of said lid and said base member has a surrounding boundary adapted to act as a tear line for the or its respective said section when said lid is first removed from said base member. This may be a line of reduced thickness of said one of said lid and said 5 base member.

The or each said section of said one of said lid and said base member may be secured to said other of said lid and said base member by welding together of abutting surfaces of said lid and said base member, and preferably by ultrasonic welding, or by the use of adhesive or solvent adhesive or other suitable means. 10 Preferably, said one of said lid and said base member is said lid. In a particularly preferred arrangement, said base member includes a peripheral flange extending outwardly from a sidewall of said base member; said lid has a part with a lower surface which when said lid is located on said base member abuts an upper surface of said flange and the or each said section of said lid is 15 secured to an upper surface of said flange. The said part of said lid may have a peripheral skirt depending therefrom with the or each said formation of said lid being formed on said skirt.

However, said one of said lid and said base member may instead be said base member. In this case, the particularly preferred arrangement disclosed in 20 the preceding paragraph may also be used, save that the sections are sections of the base member rather than the lid.

Preferably, the container has a plurality of said sections spaced apart peripherally around said container. This gives the best security against unauthorised opening or access to contents of the container. 25 In a further aspect, the invention provides a method for rendering tamper evidence on a container having a base member and a co-operating lid, said lid being resiliently snap-fitting on said base member by having one or more formations adapted to engage one or more cooperating formations of said base member, said method including the step of additionally securing at least one section of one 30 of said lid and said base member to an abutting part of the other one of said lid of said base member, so that when said lid is first removed by a user from the base member the or each said section of said one of said lid and said base member is detached from said one and remains secured to the other of said lid and said INTELLECTUAL PROPERTY OFFICE OF N.Z 19 NOV 2003 base member, thereby to provide evidence to said user of opening of said container.

In a still further aspect, the invention provides a tamper evident container including an open-topped base member and a co-operating lid or closure therefor, wherein a plurality of sections of one of said lid and said rim formation are initially secured to an abutting part of the other one of said lid and said rim formation, so that when said lid is first removed from the base member each said section of said one of said lid and said rim formation is detached from said one and remains secured to the other of said lid and said base member, thereby to provide evidence to a user of opening of said container, and wherein said lid has at least one bead formation thereon for cooperatively engaging with a rim formation of said base member whereby to retain said lid on said base member when said lid is replaced on said container after said first removal.

The container in this aspect may further include a peripheral skirt depending from an outer edge of said lid, said sections of said one of said lid and said rim formation being secured to the other of said lid and said rim formation at locations inward of said peripheral skirt. Preferably, the or at least one said bead formation on said lid is on said peripheral skirt.

Other preferred features of the container in this aspect are set out in the appended claims.

In yet a further aspect, the invention provides a tamper evident container including a base member and a co-operating lid therefor, wherein at least one section of one of said lid and said base member is initially secured to an abutting part of the other of said lid and said base member, and wherein in initial opening of said container said section is detached from said one and remains secured to said other of said lid and said base member, thereby to provide to a subsequent user evidence of said container having been opened, said container including retaining means whereby said lid is retainable on said base member subsequently to said initial opening whereby to close said Preferably, in this aspect, said at least one section is secured to said abutting part by high frequency or ultrasonic welding.

Said one of said lid and said base member may have a line of weakness surrounding the or each said section said line of weakness being adapted to act 5 as a tear line during said detachment of the or each said section.

Preferably, a said line of weakness includes at least one first portion of lesser thickness than the thickness of said one of said lid and said base member adjacent said line of weakness. This allows control of the ease of detachment of the lid from the base member, even where the one of these having the line of 10 weakness is comparatively thick. Said line of weakness may include a portion that is a perforation of said one of said lid and said base member. This further enhances the possibility of control of detachment force. Said perforated portion and said at least one first portion are preferably contiguous, for best control.

Said one of said lid and said base member may be welded to said other of 15 said lid and said base member along the or at least one said first portion. Alternatively or additionally, the or a said section may be secured to said other of said lid and said base member within a boundary defined by said line of weakness.

The appended claims further describe, and are also explicitly made a part 20 of this summary of, the invention.

The invention will now be described by reference to a particular preferred embodiment although without any intention to limit its scope to the particular embodiment.

Figure 1 is a perspective view of a container according to the invention. 25 Figure 2 is a plan view of the container shown in Figure 1.

Figure 3 is a side elevation and partial section of the container, taken along the line "AA" in Figure 2.

Figure 4 is an enlarged part of Figure 3, showing a rim of the base member and a cooperating part of the lid of the container.

Figure 5 is a perspective view of the lid of the container shown in Figure 1 shown after opening of the container.

Figure 6 is a side elevation of the lid shown in Figure 5.

Figure 7 is a perspective view of the base member of the container shown in Figure 1, after removal of the lid.

Figure 8 is a plan view of the base member shown in Figure 7.

Figure 9 is a side elevation and partial section of the base member, taken along the line "CC" in Figure 8.

Figure 10 is an enlarged part of Figure 9, showing the rim of the base member after removal of the lid.

Figure 11 is a view the same as Figure 4, except for showing platens in use for welding parts of the container together.

Figure 12 is a partial plan view of a rim of the container shown in Figure 1, in an alternative form.

Figure 13 is a cross-section of the container as shown in Figure 12 taken at station "DD".

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Figure 1 shows a container 1 according to the invention, consisting of a base member 2 and a lid 3. Base member 2 is of generally circular cross-sectional shape, although the invention is in no way limited to containers of circular shape. The invention may be applied to base members of generally square or rectangular shape, with straight or curved sides, for example, such as are known in the container art.

Base member 2 has a circular base 4 and upstanding from a periphery of the base 4 a generally upright sidewall 5, which tapers slightly outward with increasing height above base 4. Extending outwards from a top edge of sidewall 5 is a flange 6 and extending upward from an outer periphery of flange 6 is an upper sidewall 7. Extending outwards from an upper edge of upper sidewall 7 is a flange 8, and depending downwardly from an outer peripheral edge of flange 8 is a skirt 9. Skirt 9 tapers slightly outwardly with decreasing height. Upper sidewall 7, flange 8 and skirt 9 together define a rim 10 of inverted "U" cross-sectional shape. Upper sidewall 7 is shown as having a bead 11 formed thereon for reasons discussed below.

Lid 3 has a flat and circular central section 12 and a rim 13 of inverted "U" cross-sectional shape extending around the periphery of section 12. Rim 13 is defined by an upstanding wall 14, a flange 15 extending outwardly from an upper edge of wall 14 and a lid skirt 16 depending downwardly from an outer periphery of flange 15. Inwardly extending beads 17 are formed in skirt 16 and, when lid 3 is in its normal position on base member 2, extend under skirt 9 of base member 2, thereby to retain lid 3 on base member 2. To open container 1, lid 3 is removed 5 from base member 2 by pushing a part of rim 13 upward so that beads 17 are" moved out of engagement under skirt 9 and upwardly. Lid 3 deflects slightly to allow this. This part of the rim 13 is then pulled further upwardly and the lid 3 progressively disengages from base member 2 until it is fully detached therefrom.

Container 1 is of a type often made by thermoforming of plastics sheet and 10 used for products such as margarine and the like. However, the invention may be applied to containers formed wholly or in part by other known methods such as injection moulding, blow moulding, stretch-blow moulding, vacuum forming, injection-blow moulding, etc.

When lid 3 is in place on base member 2, as when product (not shown) 15 has been placed in base member 2 and the lid 3 subsequently fitted thereto, an upper surface 18 of base member flange 8 abuts a lower surface 19 of lid flange 15. To provide tamper evidence in accordance with the invention, defined parts of surfaces 18 and 19 are welded together. This may be done by ultrasonic means as is known in the art. As best seen in Figures 1 and 4, the welding is done along 20 lines 20 forming closed shapes around defined sections 21 of flange 15. Six such lines 20 and sections 21 are shown in Figure 1, peripherally equispaced around rim 13, although other numbers and peripheral spacings and locations for them may be chosen. As can be seen in Figure 4, lid flange 15 is reduced in thickness by the welding process (as further discussed below) along the lines 20. Thus lines 25 20 act as lines of weakness. When lid 3 is pulled off base member 2, sections 21 of lid 3 are torn from lid 3, separating at lines 20, and remain welded to surface 18 of flange 8. Sections 21 do not, however, prevent replacement of lid 3 on base member 2 in the ordinary way after a partial use of the contents of base member 3. After the initial removal of lid 3 from base member 2, lid 3 has holes 22 spaced 30 around its periphery on rim 13.

Container 1 is tamper-evident to an intending customer because, if lid 3 has been partially or completely removed, it will be evident to the customer that one or more sections 21 have been detached from the lid. This effect is enhanced 8 if the lid 3 and base member 2 are of differing colours. Furthermore, when the lid 3 is first removed, the effect of detaching sections 21 is that there is a definite sensation of varying resistance associated with each individual section 21 being detached from lid 23. The average resistance to lid removal is of course also 5 higher than when the lid 3 is replaced after a first opening and then removed again. Therefore even if the fact of earlier tampering has not been noticed at the time of purchase, a second, sensory indication is provided when the container 1 is next opened.

In addition to securing of lid 3 on base member 2 by co-operation of beads 10 17 and skirt 9, lid 3 is secured to base member 2 radially inwardly of sections 21. The upstanding wall 14 of lid 3 tapers slightly radially inwardly with increasing height and when lid 3 is in position on base member 2, wall 14 contacts and in part lies below bead 11, thereby to provide additional securing and/or sealing of lid 3 on base member 2. For such products as margarine, which are stored in 15 refrigerated conditions and used comparatively quickly after purchase, this additional securing is not particularly critical, but for some products such as building fillers and the like which may dry out in air, this radially inner sealing may be desirable. Lid 3 and/or base member 2 deflect slightly in known fashion to allow for lid removal.

In another arrangement, not shown, lid 3 and base member 2 may be made to at least partially seal against each other independently of beads 17 and skirt 9 by providing at least one cooperating bead or formation on upstanding wall 14 of lid 3 to engage with bead 11.

It is known to join items of thermoplastics by ultrasonic welding. As shown 25 in Figure 11, in this case, the flanges 8 and 15 are pressed between opposing platens 23 and 24 of which one platen 23 is vibrating at a suitable frequency to generate heat from small deflections and/or relative movements of parts of the flanges 8 and 15. Platen 23 is shaped with a peripheral formation 25 to produce the lines of weakness 20 as platen 23 advances partway through lid flange 15 30 during the welding process. The welding of surfaces 18 and 19 may be only along lines 20 or also over that area of the opposing surfaces within the shapes defined by lines 20, according to the height of formation 25 and the degree of advance of platen 23 toward platen 24. Although it is possible to use a single pair of platens 9 23 and 24, and move either them or the container 1 to complete welding of each of the several sections 21, it is preferred to provide a number of pairs of platens 23 and 24, each pair corresponding to one section 21.

In addition to the welding approach disclosed above, it is also possible, 5 and within the scope of the invention, to weld only the area defined within each line 20. This can be done for example by making platen 24 the vibrating one, with platen 23 merely scoring flange 15. Both platens 23 and 24 may be vibrated to achieve the welding of surfaces 18 and 19 if required.

Although not preferred, it is also possible to merely weld surfaces 18 and 10 19 together with lines 20 merely being boundaries of the welded sections 21, and with no actual reduction in thickness of flange 15 along lines 20. The disadvantage is less clean tearing away of sections 21 during initial lid removal.

A further variation is to provide for the boundary line 20 surrounding each or at least some of the sections 21 to be, in part, a line of actual penetration of 15 flange 15 and/or of flange 8 or of actual penetration of one of flange 15 and flange 8 and partial penetration of the other. One advantage of this arrangement can be reduced force for separation of each such section 21 from the lid 3, where otherwise the force would be too great. If in a particular application, manufacturing tolerances make it difficult to achieve and maintain a suitable 20 separation force by adjustment of the degree of thinning of flange 15 along line 20, it may be easier to provide for complete penetration of flange 15 along a part of the length of line 20 and a lesser degree of thinning of the remainder. Figures 12 and 13 show a section 21a with surrounding boundary line 20a the same as section 21 and boundary line 20 as described above, but now treated in this 25 particular way. The thinned part 100 of line 20a is as described above and the remaining part 101 provides no resistance to separation of section 21 due to complete penetration of flange 15. Figure 13 shows flange 8 partially penetrated, but the same result can be achieved if both flanges 15 and 8 are fully penetrated along segment 101, or even if along segment 101 flange 8 alone is fully 30 penetrated.

These arrangements can be achieved by modification of platens 23 and 24, for example by making formation 25 of greater height along a part of its periphery to produce segment 101. Alternatively, there may be a separate operation to punch segment 101 before or after the welding step.

It is possible (although not shown) for lines 20a to have multiple penetrated segments 101, and for sections 21a to be elongated peripherally. Such variations 5 can enable further tailoring of the force required to separate lid 3 from base member 2.

This variation is of most effect when welding of surfaces 18 and 19 is only along segment 100, rather than within the boundary of section 21a. Full penetration of one or the other of flanges 8 and 15 may of course also extend 10 within the boundary line 20a rather than merely along it.

Although ultrasonic welding has been disclosed as the means of joining surfaces 18 and 19, it is within the scope of the invention to use other approaches, such as heated platens (not shown) which locally melt or at least soften the surfaces 18 and 19 to achieve welding, or adhesives (including 15 solvent-type adhesives). Ultrasonic welding is particularly suitable where foodstuffs are contained in container 1.

Sections 21 are shown as circular in the figures, but it is also possible to make them of different shapes, and in particular to elongate them circumferentially.

In choosing the number and locations of the welded sections 21, it is generally desirable to space and/or size them peripherally in such a way that it is not possible to expose the contents of container 1 by lifting the rim 13 of lid 3 between any pair of sections 21 without placing either or both of that pair under sufficient stress (due to flexure of lid 3) to cause its or their separation from lid 3. 25 The detailed description of one particular container above is not intended to imply any limitation of the invention. Many further variations are possible without departing from the scope of the invention.

Claims (44)

11 WHAT WE CLAIM:

1. A tamper evident container including a base member and a co-operating lid or closure therefor, said lid being resiliently snap-fitting on said base member by having one or 5 more formations thereon adapted to engage one or more co-operating formations of said base member, and additionally at least one section of one of said lid and said base member being initially secured to an abutting part of the other one of said lid and said base member, 10 whereby when said lid is first removed from the base member the or each said section of said one of said lid and said base member is detached from said one and remains secured to the other of said lid and said base member, thereby to provide evidence to a user of opening of said container.

2. A container according to claim 1 wherein after said first removal of said lid 15 from said base member, said lid is replaceable on said base member with said one or more formations of said lid engaging said one or more cooperating formations of said base member.

3. A container according to claim 1 or 2 wherein the or a said formation on said lid faces inward and engages a peripheral rim formation on said base 20 member.

4. A container according to any one of claims 1 to 3 wherein the or each said section of said one of said lid and said base member has a surrounding boundary adapted to act as a tear line for the or its respective said section when said lid is first removed from said base member. 25

5. A container according to claim 4 wherein the or each said boundary is a line of reduced thickness of said one of said lid and said base member. 12

6. A container according to any one of claims 1 to 5 wherein the or each said section of said one of said lid and said base member is secured to said other of said lid and said base member by welding together of abutting surfaces of said lid and said base member. 5

7. A container according to claim 6 wherein said welding together of said abutting surfaces is by ultrasonic welding.

8. A container according to any one of claims 1 to 5 wherein the or each said section of said one of said lid and said base member is secured to said other of said lid and said base member by the use of adhesive or solvent adhesive. 10

9. A container according to claim 5 wherein said lid and said base member are secured together along the or each said boundary by ultrasonic welding.

10. A container according to any one of claims 1 to 9 wherein said one of said lid and said base member is said lid.

11. A container according to claim 10 wherein: 15 said base member includes a peripheral flange extending outwardly from a sidewall of said base member; said lid has a part with a lower surface which when said lid is located on said base member abuts an upper surface of said flange; and the or each said section of said lid is secured to an upper surface of 20 said flange.

12. A container according to claim 11 wherein said part of said lid has a peripheral skirt depending therefrom and wherein the or a said formation of said lid is formed on said skirt. 25

13. A container according to any one of claims 1 to 9 wherein said one of said lid and said base member is said base member. 13

14. A container according to claim13 wherein: said base member includes a peripheral flange extending outwardly from a sidewall of said base member; said lid has a part with a lower surface which when said lid is located on 5 said base member abuts an upper surface of said flange; and the or each said section of said base member is secured to said lower surface of said part.

15. A container according to claim 14 wherein said part of said lid has a peripheral skirt depending therefrom and wherein the or a said formation of said 10 lid is formed on said skirt.

16. A container according to claim 11 or 14 having a plurality of said sections spaced apart peripherally around said container

17. A method for rendering tamper evidence on a container having a base member and a co-operating lid, 15 said lid being resiliently snap-fitting on said base member by having one or more formations on said lid adapted to engage one or more co-operating formations of said base member, said method including the step of additionally securing at least one section of one of said lid and said base member to an abutting part of the other one of ^ 20 said lid of said base member, so that when said lid is first removed by a user from the base member the or each said section of said one of said lid and said base member is detached from said one and remains secured to the other of said lid and said base member, thereby to provide evidence to said user of opening of said container. 25

18. A method according to claim 17 wherein the or each said section of said one of said lid and said base member has a surrounding boundary adapted to act as a tear line for the or its respective said section when said lid is first removed from said base member. INTELLECTUAL PROPERTY OFFICE OF N.Z 19 NOV 2003 RECEIVED 14

19. A method according to claim 17 or 18 wherein the or each said section of said one of said lid and said base member is secured to said other of said lid and said base member by welding together abutting surfaces of said lid and said base member. 5

20. A method according to claim 19 wherein said welding together of said abutting surfaces is by ultrasonic welding.

21. A method according to claim 17 or 18 wherein the or each section of said one of said lid and said base member is secured to said other of said lid and said base member by the use of adhesive or solvent adhesive. 10

22. A tamper evident container including an open-topped base member and a co-operating lid or closure therefor, wherein a plurality of sections of one of said lid and said rim formation are initially secured to an abutting part of the other one of said lid and said rim formation, so that when said lid is first removed from the base member each said 15 section of said one of said lid and said rim formation is detached from said one and remains secured to the other of said lid and said base member, thereby to provide evidence to a user of opening of said container, and wherein said lid has at least one bead formation thereon for cooperatively engaging with a rim formation of said base member whereby to 20 retain said lid on said base member when said lid is replaced on said container after said first removal.

23. A container according to claim 22 further including a peripheral skirt depending from an outer edge of said lid, wherein said sections of said one of said lid and said rim formation are secured to the other of said lid and said rim 25 formation at locations inward of said peripheral skirt.

24. A container according to claim 22 or 23 wherein the or at least one said bead formation on said lid is on said peripheral skirt. 15

25. A container according to any one of claims 22 to 24 having further cooperatively engaging formations on said rim formation and said lid said further formations being located inwardly of said sections.

26. A container according to any one of claims 22 to 25 wherein at least one 5 said section of said one of said lid and said rim formation is secured to the other of said lid and said rim formation by welding.

27. A container according to claim 26 wherein said welding is ultrasonic or high frequency welding.

28. A container according to any one of claims 22 to 27 wherein at least one said section of said one of said lid and said base member has a surrounding boundary adapted to act as a preferential separation line for said section when said lid is first removed from said base member.

29. A container according to claim 28 wherein at least a part of the or each said boundary is a line of reduced thickness of said one of said lid and said base 15 member.

30. A container according to claim 28 or 29 wherein at least a part of the or each said boundary is a penetration or opening in said one of said lid and said base member.

31. A container according to any one of claims 22 to 30 wherein said sections 20 are spaced apart peripherally around said container.

32. A container according to any one of claims 22 to 31 wherein said one of said lid and said rim formation is said lid.

33. A container according to claim 29 wherein said lid and said rim formation are welded together along at least a part of the or each said boundary. 16

34. A tamper evident container including a base member and a co-operating lid therefor, wherein at least one section of one of said lid and said base member is initially secured to an abutting part of the other of said lid and said base member, 5 and wherein in initial opening of said container said section is detached from said one and remains secured to said other of said lid and said base member, thereby to provide to a subsequent user evidence of said container having been opened, said container including retaining means whereby said lid is retainable on 10 said base member subsequently to said initial opening whereby to close said container.

35. A container according to claim 34 wherein said retaining means includes at least one first formation on said lid and a second formation on said base member said first and second formations being cooperatingly engageable with each other 15 when said container is closed.

36. A container according to claim 35 wherein said second formation is or is included in a peripheral rim formation on said base member.

37. A container according to claim 36 wherein when engaged with said second formation said first formation faces inwardly towards said peripheral rim formation. 20

38. A container according to any one of claims 34 to 37 wherein said at least one section is secured to said abutting part by high frequency or ultrasonic welding.

39. A container according to any one of claims 34 to 38 wherein said one of said lid and said base member has a line of weakness surrounding the or each 25 said section said line of weakness being adapted to act as a tear line during said detachment of the or each said section. 5 2 8 6 18 17

40. A container according to claim 39 wherein a said line of weakness includes at least one first portion of lesser thickness than the thickness of said one of said lid and said base member adjacent said line of weakness.

41. A container according to claim 40 wherein said line of weakness includes a 5 portion that is a perforation of said one of said lid and said base member.

42. A container according to claim 41 wherein said perforated portion and said at least one first portion are contiguous.

43. A container according to any one of claims 40 to 42 wherein said one of said lid and said base member is welded to said other of said lid and said base 10 member along the or at least one said first portion.

44. A container according to any one of claims 40 to 43 wherein the or a said section is secured to said other of said lid and said base member within a boundary defined by said line of weakness. 15 HUHTAMAKI AUSTRALIA LIMITED by their Patent Attorneys WATERMARK PATENT & TRADE MARK ATTORNEYS END OF CLAIMS A tamper evident container suitable for delivery of foodstuffs and the like. The container includes a base member and a co-operating lid or closure therefor. The lid is resiliently snap-fitted on the base member by having one or more formations thereon adapted to engage one or more co-operating formations of the base member Additionally, at least one section of one of the lid and the base member is initially secured to an abutting part of the other one of the lid and the base member. When the lid is first removed from the base member the or each section of the lid or the base member is detached therefrom and remains secured to the other of the lid and the base member, thereby to provide evidence to a user of opening of the container. A method for rendering tamper evident a container is also disclosed.