CA2049066A1

CA2049066A1 - Tamper-evident push-in closure

Info

Publication number: CA2049066A1
Application number: CA002049066A
Authority: CA
Inventors: Peter Lewis Revill; Alan George Dalli
Original assignee: Individual
Current assignee: Broken Hill Pty Co Ltd
Priority date: 1989-03-17
Filing date: 1990-03-16
Publication date: 1990-09-18
Also published as: AU634762B2; EP0464061A4; AU5282190A; EP0464061A1; ES2066197T3; DE69015351T2; KR920701004A; EP0464061B1; DE69015351D1; WO1990011226A1; JPH04504093A; ATE115935T1; ZA902053B

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

2 ~ ~ 9 ~ fi ~ PCI/~U~0/0011)~

I
TITLE: T~lPER-E~IDE~T Pl'SH-I`; CLOS~'RE
Field of che In~ention This invention relates to push-in closures of the eas--oper.ino t-re, and more particularly to tamper-e~ident closures Gf this t-pe.
Bac~;oround of the Tn-~en ion Push-in easv-opening closures of the full- sheared type ha~e now been in commercial production for over a decade.
The ~hO currentli a~ailable t~pes of push-in easy-opening closure- are described in our ~!nited States Patent ~o.
'.~6-,3~. in hhich FiQure l shows a push-in eas!-open can end ~esionated Presto l. whi e later fi ures show ~arious form,:- o a., end desionated Presto ~.
Gn- c- th- ~rimary difficulcies wich a full; sheared push-in eas~-opening closure is that it ma~ be susceptible to inadvertent or surreptitious opening of the can durino commercial handling or while the product is on the supermarket shelves for sale. .~ccidental opening of the small closu}e or tab by means of rough or careless handling of a can may result in the small tab in particular being partially opened to allo~ escape of gas or contents.
However, the small tab ~ill 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 displa- in a supermarket, usuall~ by children, who shake the can and sli~htl open the small tab b- means of a tooth to enable some of the contents to be consumed, whereupon the can is replaced on the supermarket shelf.
Summar~ of Inventlon and Obiect It is an object of the present invention to provide a means by which the above described t~pes of opening ma~ be ~:' made more difficult, and more importantlv, ma~ be made visible, or otherwise evident, sucn as by leaka~e of the contents, co the purchaser.
In one form, the in-~ention Dro~ides a push-in eas--openino closure in a shee~ mera: container member.
comprisinc an openin~ in ~ne con~alr.-r member. an inte~r ' .

~090/112~6 ~ PCT/AUgO/~0108 c].osure member for the openinC formed b~ at least partiallv severing the container member, said closure member being in overlapping and underlving relationship with the free ed~e portion of said container member defining said opening. and sealant means applied to the region of the edge of the closure member and the free edge portion of said container member on the inside of said container member, characterised in tnat the free edge portion of said closure member is formed with at least one latch member dimensioned to engages the rree edge portion of said contaiher member defining said opening tc increase the push-in force required to open said closure member to a level which ensures tna~. said sea~ant is full~. bro~en ;~hene~Pr said closure member is opened. said latch means fur~her pre-enting said closure member resealin-aîter opening.
In one preferred arrangement, the or each latch member comprises a narrow element of said free edge portion of said closure member which slightly overlies the free edge portion of the container member defining said opening. In this form of the invention, the latch member must be displaced past said free edge portion of said container member defining said opening during the opening process. Since the latch member is slightl- larger in effective diameter than the openingt the closure member is unable to return to the closed position after it has been opened.
Alternatively, the or each latch member comprises a narro~ portion of the free edge portion of the closure member which is reduced in effective diameter to approximatel~ the same diameter as said opening, and is displaced into the same plane as the plane of the free edge portion of the container member defining said opening where it binds against said free edge portion to increase the force required to open the closure. Since the binding force is released when the closure is opened, the free edge portion of the container member defi.ning the opening wili reduce slightl~ in diameter to prevent the closure member : being repositioned in its closured position after opening.
In a particularl~ preferrei form of each of tne a 3 0 ve WO90/112~6 2 ~ ~.19 ~ ~ ~ Pcrl~uso/oo~os - ~ -embodiments. the closure member is integrall~ connected t~
the container member b!.means o:E a narro~ neck of metal definino a hinge connection fcr the closure member The closure member is preferabl~ formed ~ith t~o anQuiarl-s?aced latch members of either of the abo-e t~pes. each position at about 90 to 140~ from the centre OI the n2rron nec~ of metal. In the case of small closure members. and some laroe closure members, onl~ one latch member need be proviàed and it is preferabl~ positioned directl~ opposite the hinge connection I i, a concern o~ some be~erage manuLacturers tha~
foreig.. suss.a.lces ma. be introduced in., the concainer throug;. th^- r,ush-in closure ~ithout being able to be ~-ib'l~
detected. It is therefore another obJect of ..,- present invention to pro~ide a modified closure design hhich inhibits the insertion of foreign obJects into th- container through the r,ush-in eas~-opening closure member In another form, the inYention provides a pusn-in eas~-opening closure in a sheet metal container member comprising an opening in the container member, an integral closure member for the opening formed b~ partiall~ severing the container member. said closure me'mber being in overlapping and underl~ing relationship to the free edge portion of said container member defining said opening seaiant means applied to the closure member and said free edge por~ion oî
said container member defining said opening on the inside of said:container, said closure member being formed ~ith a central upstanding portion and an out~ardlY extending rim portion which underlies said free edge portion of said container member, said upstanding portion being dimensioned so as to be in close proximit~ to said free edge portion of said container member to thereb~ restrict the entr~ of foreign objects through said closure ~ithout isibl~ opening said closure.
The upstandin~ portion preferab'~; has sides ~h c. ar-^
as close to per?endicular to the ri-. as m~. be Dractica'l~.
achie~ec`. Thls lurther increases the -'fficul~- in inser~lng a.n ob1ect bet~een the closure -em.ber ar.d ~he :'ree ~-e .

~'090/11226 1'Cr/~U~0/0010~
~ ~ L~

portlon surrouriln~ th~e opening.
In a parti~u!ar1~ pre erred form of thi 5 aspect c' t.he invention. the flrct defined as?ect oL the inventiGn lS alsG
included tc fur;he~ lncreacG the likeiihood that.tamperinr ~ith thG closure ~.emt~-r ~i'' be detected.
T~o pre~errec I O rms O t the abo-~e aspects o. the in~ention ~ill no~ be described ~ith reference tc the accompan~ino dra~ings in hhiCh:
Fioure 1 is 2 fra~mer.t3r! plan ~ ieh OI a can end hc-ini~
push-in ea-:-openin~ closure member of tne Presto i t;pe modifled i-; acrorca.,cc hlth one preferre, ror. O~ ~ne in~e.ntio.i:
F~3~r-- i a _ ~ r rs r G c~ e h O f the ?ourin~ r i r` S ~ r oi Fioure i:
Figures 3 ar.d - are sectiGnal elevations taken along ~hG lir.es 3-3 and --' respecii~el~ in Figure l Figures ~ tc are ~ie~s correspondinr; to Fi~ures 1. ~
and ', shohlno a modified form OL the invention, and :
Figures 8 and 9 are ~iehs similar tû Figures ~ and /
showing a modified form of the embodiment of Figures ~ and 7.
Referrinr tirstl~ to Figures 1 to 4 of the dra~ings, the closure member embod~in the in~ention will be seen to .;
comprise a Qenerall~ circular pou.ing ûpening i and 3 smalier pressure reieasing/~enting opening la formed in a can end 2 bs parti ll~ se~erir.g the sheet metal- to form.
closure members 3 and 3a hhich are integrail~ connected to the can end 2 b-~ means of narrow necks of metal * and 4a defining a ~.in e means for each closure member 3 and 5. An , upstanding semi-circular. bead B partl~ surrounds the pressure releasing closure 3a to protect it agains r inadvereent opening durinr. handlin_. Sin:e the closure members 3 and 3a are essentiall~ the same in construction, onl~ the pouring closure 3 hill be iurther described bela~.
~ rhe closure memDeers ~ and , for-,ed ~ith an upstan-iin~
domec portio.. ~ surrounded ~: a^. Gut~ardl~ extendin~ r ~. ~.
The rim ;) is cis r` C S ed ir. c,~ G ` i a ^ D i no and under~.ln-relaticns~ ^....... . ;re- edge ?^-:i~n , or the {~.~ ?.. - ,'., I .

.`:

WO90/11226 2 ~ cr/~u~o/~olox around said openir)C~ 1 achleved b~ fiattening a dome formed in said free edoe portion / in the manner ùescribed in greater detail in our .-~ustrali.an Patent ~o. A~:-B,3304~/,1 (4~,06~). If deslred. the closure member 3 ma~ additionall~.
be coined at the rim 6, prior to the flattening operatiGn,tc increase the diameter of the closure member , and increase the amount of overlap provided. I`he top of the dome 5 ma~.
also be cointed to further increase the diameter of the closure member 3 is increased. In accordance ~ith usual practice. the overlappin_ regions are cove~ed b- a suitable sealant S to hermeticall- sea the c`1osure ~e-.bers ~, and ,a ~ith respect ~o thQ o?enin~-s l ar.d la.
To enable inadverter., cr su.re~itio s o?enln~ cf tr.e closure member tc be readil~ detectec. and to reduc-undetectable acce~s to the cor,tents of the container b~
thin probes, the rim 5 of the closure is formed hith t~G
latch members & and 9 which overlap and overl~ the free edge portion / of the can end ~ at positions displaced ar,out 120-from the centre of the hinge 4 in either direction. It ~ill be appreciated that the latch members 8 and 9 ma~ be located at other positions, such as at 90 from the centre of the hinge 4, or a single latch member ma~ be located opposite the hinge 4.
In addition to the above~ the diameter of the domed portion 5 is increased so that its side hali is as close as possible to the free edge portion / of the can end 2 and so that the side ~all is as close as possible to perpendicular to the rim 6 thereby increasing the height of the dome 5 compared with earlier versions of tne Presto 1 closure. ln the present embodiment. the height of the dome 5 is of the order of 1.30 mm while the gap between the side hall of the dome 5 and the free edge portion 7 i5 onl~ of the order of 0.5 mm, and mav be as small as 0.~5 mm. 3~ virtue of the closeness of the side hall of the dome 5 to the free edge portion 7, its increased height an- the stee?ness o tre ~all angle. C~reat difficult- ~ou i be e~?erlencei in inserting even a small thin probe betieen tne closure membe!

3 and the free eb~e portior. ~ .ii~:nou~ si~n-ticar.t1~ oDeni1-~.

.. .. . . ..

WO90/11226 2 ~ O ~ ~ PC~/AU90/00108 ~,, _ the closure member 3, and once opening occurs, the latchmembers ~ and 9 pre~ent recioslng so that opening is ~isuall~ apparent.
The latches 8 and 9 are forrned during or immediatel-after the sheet metal severing operation in ~hich the closure member 3 and the opening l are initiall~ defined.
The closure member 3 is displaced belo~ the free edge portion 7 prior to the flattening of the free edge portion 7 to reduce the diameter of rhe opening l, while the latcnes 8 and 9, bein2 uphardl~: inclined ~ith respect to the remaining portion of the rim 6~ as sho~n ln Figure 4, are disposed in o~erl~;inA relat~onshi~ tc the free ed~e portion 7 after flat~ening.
The amount of o~eriap between the latch members ~ and c and the free ed~e portion 7 sho~n in Figure 4 is exaggerated :~
for clarit~, but is selected to be sufficient to increase the opening force required to be approximatel~ equal to the force required to rupture the sealant S which is applied to the inner face of the can end A~ 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 l, the closure member 3 is not able to return to the fullv closed position after opening. In this ~a~, opening of the closure member 3.mav be readil~ detected ~isuall- and the contents :of the~can will be more likel- to leak from the ca., to provide further e-idence of tampering. . :
: In the embodiment shown in Figures ~ to 7 of the drawings, the construction:of the closure is essentiall~ the same as in the preceiing embodiment, ~ith the excep~ion that the latch members 8' and 9' are positioned in abutting relationship ~ith the free edge portion 7 of the can end A~ ;
: : :in the mann e r shown most clearl~ in Figure 8 of the i.
: dra~ings. Since the rim 6 is usuall~ in overlapping ..
underlving relationship ~ith the free edge portior, 7. the .-: latch. members ~' and 9' ~orcibl~ engage the free edoe portion 7 so thar the force re. ~re~ tG open the closure member 3 is increased sufficien.~ ensure that clGsure member 3 ~ill be fu. ~ opene~ he a?p'icaticr ~"-: ~ : :
:

: ~ .

WO90/11226 2 ~ PCI/AU90/0iO108 , necessar~. push-in forc~ ccordi.n~l! oDening o~ the closure member 3 ~ill be much more ~isible than in the past. and rhe contents of the can ~ill tend to lea~ from the can as further e~idence of its opening. In Fioures 6 and ~, the height o.E the latch means 8 and 9' has been e~aggerated for clarit-.
The embodirnent of Figures ~ to / is presentl~ preferred as it performs acceptabl! in practice and is nct as noticeabl! different from a standard Presto l construclion as the err,bodiment of Figures 1 to '. ~o~ever, in this embodimen~, the flatter.ing of the free edge portion ; to prGduce the necessar- o~e lap can result ~n displacem--..t G'-the closure 3. caused G~' the flarte.ing Ot the hinoe- -r lc^.
',, causin^ unacce?tabie ~i~.din~ ol the latch m,eans a..c 9'. To reduce this effec., the radial se-er line_ L
defining the hinge 4 (and the hinçe 4a) are e.Yrended as shoh,n in broken outline in Figures 1 and 2, to allo~ this part Ot 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 embodimer~t shohn in Figures ~ and 9 of the drawings, the closures 3 and 3a (not sho~n) are each formed ~ith additional abutments lO, ~hich are similar in appearance to the latch means Ç~' anà 9' but are not full~
formed to engage the free edge por~ion /, as sho~n most clearl~ in Figure 9 of the dra~ings. The purpose of the abutments lO is to further deter t.he insertion of small thin probes, which MUst be angularly inserted at the periphery of the openino 3 in a sliding motion around the peripher~. The abutments 10 and the latches 8' and 9' prevent this sliding motion and further deter such activities. ~.
While only one t~e of closure -.ember 3 has been sno~n in the accompanving drahings, it ~i:l be appreciated that latch members can be formed in each ~f the closure rrlember~
according to the Presto _ desion. altnou~ t ~i'' ce appreciated that the smaller press~re reieaairl- clos~re ~ember of the Pres~c ~ desi~n ~o~ - :n such a cace ce ~

WO 90/11226 PCl~/AIJ90/00108 6 ~

ha\e the pressure resealing propert~ deseribed in ~reater detail in the .~us~ralian and l'nlted States patent relerred to abo~e.

,:
: '.

:, : ~ . :, :
~ " '' , : ~ :
; ~ :

Claims

CLAIMS:

1. A push-in easy-opening closure in a sheet metal opening 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, said closure member being in overlapping and underlying relationship with the free edge portion of said container member defining said opening. and sealant means applied to the region of the edge of the closure member and the free edge portion of said container member on the inside of said container member, characterised in that the free edge portion of said closure member is formed with at least one latch member dimensioned to engages the free edge portion of said container member defining said opening to increase the push-in force required to open said closure member to a level which ensures that said sealant is fully broken whenever said closure member is opened, said latch means further preventing said closure member resealing after opening.

2. The closure of claim 1, wherein the or each latch member comprises a narrow element of said free edge portion of said closure member which slightly overlies the free edge portion of the container member defining said opening.

3. The closure of claim 1, wherein the or each latch member comprises a narrow portion of the free edge portion of the closure member which is reduced in effective diameter to approximately the same diameter as said opening, and is displaced into the same plane as the plane of the free edge portion of the container member defining said opening where it binds against said free edge portion to increase the force required to open the closure.

4. The closure of any one of claims 1 to 3, 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.

5. The closure of claim 4, comprising two angularly spaced latch members of either of the above types, each position at about 90° to 140° from the centre of the narrow neck of metal.

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

7. A push-in easy-opening closure in a sheet metal container member comprising an opening in the container member, an integral closure member for the opening formed by partially severing the container member, said closure member being in overlapping and underlying relationship to the free edge portion of said container member defining said opening, sealant means applied to the closure member and said free edge portion of said container member defining said opening on the inside of said container, said closure member being formed with a central upstanding portion and an outwardly extending rim portion which underlies said free edge portion of said container member, said upstanding portion being dimensioned so as to be in close proximity to said free edge portion of said container member to thereby restrict the entry of foreign objects through said closure without visibly opening said closure.

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

9. The closure of claim 7 or 8, further comprising at least one latch member as defined in any one of claims 1 to 6.

10. The closure of any preceding claim, further comprising abutments formed in the free edge portion of said closure member at spaced positions around the periphery of said closure member, said abutment portions being position and configured to deter the insertion of small narrow probes between said closure member and said opening.

11. A push-in easy-opening closure substantially as hereinbefore described with reference to Figures 1 to 4 or 5 to 7 or 8 and 9 of the accompanying drawings.