AU634762B2

AU634762B2 - Tamper-evident push-in closure

Info

Publication number: AU634762B2
Application number: AU52821/90A
Authority: AU
Inventors: Alan George Dalli; Peter Lewis Revill
Original assignee: Broken Hill Pty Co Ltd
Current assignee: Broken Hill Pty Co Ltd
Priority date: 1989-03-17
Filing date: 1990-03-16
Publication date: 1993-03-04
Anticipated expiration: 2010-03-16
Also published as: DE69015351T2; KR920701004A; EP0464061A1; CA2049066A1; EP0464061B1; ZA902053B; JPH04504093A; WO1990011226A1; ES2066197T3; DE69015351D1; EP0464061A4; ATE115935T1; AU5282190A

Abstract

A tamper-evident push-in easy-opening closure in a sheet metal container member comprising an opening (1) in the container member (2), an integral closure member (3) for the opening in overlapping and underlying relationship with the free edge portion (7) defining the opening (1), the free edge portion (6) of the closure member (3) being formed with spaced latch members (8, 9; 8', 9') dimensioned to engage the free edge portion (7) around the opening (1) to increase the push-in force required to open the closure member (3) to a level which ensures that sealant (S) for sealing the closure member (3) in the opening (1) is fully broken whenever the closure member is opened, said closure member (3) being formed with a central upstanding portion (5) dimensioned to be in close proximity to said free edge portion (7) and being substantially perpendicular to a rim (6) extending from said upstanding portion (5), to thereby restrict the entry of foreign objects through said closure without visibly opening said closure.

Description

OPI DATE 22/10/q0

PC

AOJP DATE 29/11/90

INTERNATIO

APPLN. ID 52821 PCT NUMBER PCT/AU90/00108 ,ATY (PCT) (51) International Patent Classification 5 (11)International Publication Number: WO 90/11226 17/28, 17/32 Al B65D 101/00 (43) International Publication Date: 4 October 1990 (04,10.90) (21) Interi4ional Application Number: PCT/AU90/00108 (74)Agent: SMITH SHELSTON BEADLE; 207 Riversdale Road, Hawthorn, VIC 3122 (AU), (22) International Filing Date: 16 March 1990 (16.03.90) (81) Designated States: AT, AT(European patent), AU, BB, BE Priority data: (European patent), BF (OAP1 patent), BG, BJ (OAPI PJ 3259 17 March 1989 (17.03,89) AU patent), BR, CA, CF (OAPI patent), CG (OAPI patent), CH, CH (European patent), CM (OAPI patent), DE, DE (European patent), DK, DK (European patent), ES, (71) Applicant (for all designated States except US): THE BRO- ES (European patent), FI, FR (European patent), GA KEN HILL PROPRIETARY COMPANY LIMITED (OAPI patent), GB, GB (European patent), HU, IT(Eu.

[AU/AU]; BHP House, 140 William Street, Melbourne, ropean patent), JP, KP, KR, LK, LU, LU (European pa- VIC 3000 tent), MC, MG, ML (OAPI patent), MR (OAPI patent), MW, NL, NL (European patent), NO, RO, SD, SE, SE (72) Inventors; and (European patent), SN (OAPI patent), SU, TD (OAPI Inventors/Applicants (for US only) REVILL, Peter, Lewis patent), TG (OAPI patent), US.

[AU/AU]; 22 Mary Street, St Kilda, VIC 3182 (AU).

DALLI, Alan, George [AU/AU]; 9 Taroona Avenue, Warrandyte, VIC 3113 Published With international search report.

634762 (54) Title: TAMWPER-EVIDENT PUSH-IN CLOSURE (57) Abstract A tamper-evident push-in easy-opening closure in a sheet metal container member comprising an opening in the container member an integral closure member for th(. opening in oveirapping and underlying relationship with the free edge portion defining the opening the free edge portion of the closure member being formed with spaced latch members 9; dimensioned to engage the free edge portion around the opening to increase the push-in force required to open the closure member to a level which ensures that sealant for sealing the closure member in the opening is fully broken whenever the closure member is opened, said closure member being formed with a central upstanding portion dimensioned to be in close proximity to said free edge portion and being substantially perpendicular to a rim extending from said upstanding portion to thereby restrict the entry of foreign objects through said closure without visibly opening said closure.

See back of page WO 90/11226 PCT/AU90/00108 1 1 TITLE: TAMPER-EVIDENT PUSH-IN CLOSURE Field of the Invention This invention relates to push-in closures of the easyopening type, and more particularly to tamper-evident closures of this type.

Background of the Invention Push-in easy-opening closures of the fully sheared type have now been in commercial production for over a decade.

The two currently available types of push-in easy-opening closures are described in our United States Patent No.

4,267,938, in which Figure 1 shows a push-in easy-open can end designated Presto 1, while later figures show various forms of can end designated Presto 2.

One of the primary difficulties with a fully sheared push-in easy-opening closure is that it may be susceptible to inadvertent or surreptitious opening of the can during commercial handling or while the product is on the supermarket shelves for sale. Accidental opening of the small closure or tab by means of rough or careless handling of a can may result in the small tab in particular being partially opened to allow escape of gas or contents.

However, the small tab will usually reseal in such circumstances so that the end purchaser may not be aware that such opening has occurred. Of more concern is the surreptitious opening while the can is on display in a supermarket, usually by children, who shake the can and slightly open the small tab by means of a tooth to enable some of the contents to be consumed, whereupon the can is replaced on the supermarket shelf.

Summary of Invention and Object It is an object of the present invention to provide a means by which the above described types of opening may be made more difficult, and more importantly, may be made visible, or otherwise evident, such as by leakage of the contents, to the purchaser.

Ing ea f9cn -4m h in t ntion prtiic a puh in2 r opening closure in a container member, -e -t cn ae membo an integral- -2- The invention provides a push-in easy-open closure in a sheet metal container member comprising: an opening in the container member; an integral closure member for the opening formed by at least partially severing the container member to form the closure member and the opening, said closure member having a free edge portion terminating in a free edge, said free edge portion being disposed in a first stratum and in overlapping relationship with a free edge portion of said container member around said opening, said free edge portion of said container member being disposed in a second'stratum and having a free edge, said first stratum underlying said second stratum; sealant means applied to the closure member and to an adjacent portion of the free edge portion of said container member on an inside of the container member; and at least one latch member formed at said free edge portion of said closure member, said at least one latch member including a narrow portion of the free edge portion of the closure member which has been displaced from said first stratum to said second stratum to form an edge portion of said latch member which abuts against said free edge of said container member to increase a push-in force required to open said closure member such that said sealant means is broken when said closure member is opened, said latch member further substantially inhibiting said closure member resealing after opening.

In a particularly preferred form of each of the above embodiments, the closure member is integrally connected to the container member by means of a narrow neck of metal defining a hinge connection for the closure member. The closure member is preferably formed with two angularly spaced !atci, members of either of the above types, each position at about 900 to 1400 from the centre of the narrow neck of metal. in the case of small closure members, and some large closure members, only one latch member need be provided and it is preferably positioned directly opposite the hinge connection.

It is a concern of some beverage manufacturers that foreign substances may be introduced into the container through the push-in closure -3without being able to be visibly detected.

In a preferred form, the closure member is formed with a central upstanding portion and an outwardly extending rim portion which includes said free edge portion, said upstanding portion being dimensioned to be in such close proximity to said free edge portion of said container member to restrict the entry of foreign objects between said free edge portion of said container member and said closure member without visibly opening said closure.

The upstanding portion preferably has sides which are as close to perpendicular to the rim as may be practically achieved. This further increases the difficulty in inserting an object between the closure member and the free edge portion surrounding the opening.

In a particularly preferred form of this aspect of the invention, the first defined aspect of the invention is also included to further increase the likelihood that tampering with the closure member will be detected.

Two preferred forms of the above aspects of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a fragmentary plan view of a can end having push-in easyopening closure member of the Presto 1 type modified in a manner which led to the present invention; Figure 2 is a perspective view of the pouring closure of Figure 1; Figure 3 and 4 are sectional elevations taken along the lines 3-3 and 4-4 respectively in Figure 1; Figures 5 to 7 are views corresponding to Figures 1, 2 and 4 showing the preferred form of the invention, and Figures 8 and 9 are views similar to Figures 5 and 7 showing a modified form of the embodiment of Figures 5 and 7.

Referring firstly to Figures 1 to 4 of the drawings, the closure member will be seen to comprise a generally circular pouring opening I and a smaller pressure releasing/venting opening la formed in a can end 2 by partially severing the sheet metal to form closure members 3 and 3a which are integrally connected to the can end 2 by means of narrow necks of metal 4 and 4a defining a hinge means for each closure member 3 and 5. An //8481BIHP -4upstanding semi-circular bead B partly sur ounds the pressure releasing closure 3a to protect it against inadvertent opening during handling. Since the closure members 3 and 3a are essentially the same in construction, only the pouring closure 3 will be further described below.

The closure members 4 and 5 formed with an upstanding domed portion surrounded by an outwardly extending rim 6. The rim 6 is disposed in overlapping and underlying relationship with a free edge portion 7 of the can end #8481BHP WO 90/11226 PCT/AU90/00108 around said opening 1 achieved by flattening a dome formed in said free edge portion 7 in the manner described in greater detail in our Australian Patent No. AU-B,33044/71 (444,068). If desired, the .closure member 3 may additionally be coined at the rim 6, prior to the flattening operation,to increase the diameter of the closure member 3 and increase the amount of overlap provided. The top of the dome 5 may also be cointed to further increase the diameter of the closure member 3 is increased. In accordance with usual practice, the overlapping regions are covered by a suitable sealant S to hermetically seal the closure members 3 and 3a with respect to the openings 1 and la.

To enable inadvertent or surreptitious opening of the closure member to be readily detected, and to reduce undetectable access to the contents of the container by thin probes, the rim 6 of the closure is formed with two latch members 8 and 9 which overlap and overly the free edge portion 7 of the can end 2 at positions displaced about 120° from the centre of the hinge 4 in either direction. It will be appreciated that the latch members 8 and 9 may be located at other positions, such as at 90° from the centre of the hinge 4, or a single latch member may be located opposite the hinge 4.

In addition to the above, the diameter of the dcmed portion 5 is increased so that its side wall is as close as possible to the free edge portion 7 of the can end 2 and so that the side wall is as close as possible to perpendicular to the rim 6 thereby increasing the height of the dome compared with earlier versions of the Presto 1 closure. In the present embodiment, the height of the dome 5 is of the order of 1.30 mm while the gap between the side wall of the dome 5 and the free edge portion 7 is only of the order of mm, and may be as small as 0.25 mm. By virtue of the closeness of the side wall of the dome 5 to the free edge portion 7, its increased height and the steepness of the wall angle, great difficulty would be experienced in inserting even a small thin probe between the closure member 3 and the free edge portion 7 without significantly opening WO 90/11226 PCT/AU90/00108 6 the closure member 3, and once opening occurs, the latch members 8 and 9 prevent reclosing so that opening is visually apparent.

The latches 8 and 9 are formed during or immediately after the sheet metal severing operation in which the closure member 3 and the opening 1 are initially defined.

The closure member 3 is displaced below the free edge portion 7 prior to the flattening of the free edge portion 7 to reduce the diameter of the opening 1, while the latches 8 and 9, being upwardly inclined with respect to the remaining portion of the rim 6, as shown in Figure 4, are disposed in overlying relationship to the free edge portion 7 after flattening.

The amount of overlap between the latch members 8 and 9 and the free edge portion 7 shown in Figure 4 is exaggerated for clarity, but is selected to be sufficient to increase the opening force required to be approximately equal to the force required to rupture the sealant S which is applied to the inner face of the can end 2 in the region of the rim 6 and free edge portions 7. Since the latch members 8 and 9 are larger in effective diameter than the opening 1, the closure member 3 is not able to return to the fully closed position after opening. In this way, opening of the closure member 3 may be readily detected visually and the contents of the can will be more likely to leak from the can to provide further evidence of tampering.

In theembo iment shown in Figures 5 to 7 of the drawings, the construction of the closure is essentially the same as in the preceding embodiment, with the exception that the latch members 8' and 9' are positioned in abutting relationship with the free edge portion 7 of the can end 2, in the manner shown most clearly in Figure 8 of the drawings. Since the rim 6 is usually in overlapping underlying relationship with the free edge portion 7, the latch members 8' and 9' forcibly engage the free edge portion 7 so that the force required to open the closure member 3 is increased sufficiently to ensure that closure member 3 will be fully opened by the application of the

A

JPo~" WO 90/11226 PCT/AU90/00108 7 necessary push-in force. Accordingly, opening of the closure member 3 will be much more visible than in the past, and the contents of the can will tend to leak from the can as further evidence of its opening. In Figures 6 and 7, the height of the latch means 8' and 9' has been exaggerated for clarity.

The embodiment of Figures 5 to 7 is presently preferred as it performs acceptably in practice and is not as noticeably different from a standard Presto 1 construction as the embodiment of Figures 1 to 4, However, in this embodiment, the flattening of the free edge portion 7 to produce the necessary overlap can result in displacement of the closure 3, caused by the flattening of the hinge region 4, causing unacceptable binding of the latch means 8' and To reduce this effect, the radial sever lines L defining the hinge 4 (and the hinge 4 a) are extended as shown in broken outline in Figures 1 and 2, to allow this part of the metal to absorb some of the free metal resulting from the flattening operation, and reducing the displacement of the closure 3 to acceptable levels.

In the embodiment shown in Figures 8 and 9 of the drawings, the closures 3 and 3a (not shown) are each formed with additional abutments 10, which are similar in appearance to the latch means 8' and 9' but are not fully formed to engage the free edge portion 7, as shown most clearly in Figure 9 of the drawings. The purpose of the abutments 10 is to further deter the insertion of small thin probes, which must be angularly inserted at the periphery of the opening 3 in a sliding motion around the periphery. The abutments 10 and the latches 8' and 9' prevent this sliding motion and further deter such activities, While only one tye of closure member 3 has been shown in the accompanying drawings, it will be appreciated that latch members can be formed in each of the closure members according to the Presto 2 design, although it will be appreciated that the smaller pressure releasing closure member of the Presto 2 design would in such a case cease to WO 90/ 11226 PCT/AU90/OO1 08 -8have the p ressu re re seal ing property desc ri bed in greater detail in the Au~tralian and United States patent referred to above.

Claims

1. A push-in easy-open easy-open closure in a sheet metal container member comprising: an opening in the container member; an integral closure member for the opening formed by at least partially severing the container member to form the closure member and the opening, said closure member having a free edge portion terminating in a free edge, said free edge portion being disposed in a first stratum and in overlapping relationship with a free edge portion of said container member around said opening, said free edge portion of said container member being disposed in a second stratum and having a free edge, said first stratum underlying said second stratum; sealant means applied to the closure member and to an adjacent portion of the free edge portion of said container member on an inside of the container member; and at least one latch member formed at said free edge portion of said closure member, said at least one latch member including a narrow portion of the free edge portion of the closure member which has been displaced from sid first stratum to said second stratum to form an edge portion of said latch member which abuts against said free edge of said container member to increase a push-in force required to open said closure member such that said sealant means is broken when said closure member is opened, said latch member further substantially inhibiting said closure member resealitlg after opening.

2. The closure according to claim I wherein the or each latch member is formed in the closure member to define said edge portion of said latch member in a position inwardly of said closure member free edge to leave an adjacent portion of said closure member edge in underlying relationship with said free edge portion of said container member,

3. The closure of claim I or 2, wherein said closure member is integrally connected to the container member by means of a narrow neck of metal defining a hinge connection for the closure member.

4. The closure according to claim 3, further comprising upstanding #8481BHP 10 abutments formed in said closure member edge at positions spaced from but adjacent to said narrow neck of metal, said abutments being of similar form to said latch means but not being fully formed to abut said free edge portion of said container member, said abutments being positioned to further deter insertion of small thin probes between said closure member and said free edge portion of said container member.

The closure of claim 3 or 4, comprising two angularly spaced latch members each positioned at about 900 to 1400 from the centre of the narrow neck of metal.

6. The closure of claim 3, 4 or 5, comprising one latch member positioned substantially opposite said hinge connection.

7. The closure of any preceding claim, said closure member being formed with a central upstanding portion and an outwardly extending rim portion which includes said free edge portion, said upstanding portion being dimensioned to be in such close proximity to said free edge portion of said container member to restrict the entry of foreign objects between said free edge portion of said container member and said closure member without visibly opening said closure.

8. The closure of claim 7, wherein the sides of said upstanding portion are substantially perpendicular to said rim.

9. A push-in easy-opening closure substantially as hereinbefore described with reference to Figures 5 to 7 or 8 and 9 of the accompanying drawings. DATED this 4 January, 1993 CARTER SMITH BEADLE Felk ws Institute of Patent Attorneys of Australia Patent Attorneys for the Applicant: THE BROKEN HILl PROPRIETARY COMPANY LIMITED #8481BHP