Note: Descriptions are shown in the official language in which they were submitted.
WO90/11226 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 '
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~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
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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~
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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 {~.~ ?.. - ,'.,
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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-
~.
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WO90/11226 2 ~ O ~ ~ PC~/AU90/00108
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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 ~"-
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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.
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