CA2113338A1

CA2113338A1 - Full open can end closure

Info

Publication number: CA2113338A1
Application number: CA002113338A
Authority: CA
Inventors: John Alan Walmer Slade; Dietmar Salm
Original assignee: Individual
Current assignee: Broken Hill Pty Co Ltd
Priority date: 1991-07-11
Filing date: 1992-07-10
Publication date: 1993-01-21
Also published as: EP0592550B1; WO1993001096A1; EP0592550A1; NZ243519A; ATE152413T1; DE69219473D1; JPH06509045A; EP0592550A4

Abstract

A can end closure comprises (i) a panel formed with a rim portion (2) and (ii) a central panel (4) substantially fully severed from the rim portion (2) and having a peripheral free edge portion (5). The rim portion is formed with spaced parallel folded portions (F1 and F2) defining a groove G within which the peripheral free edge portion (5) of the central panel (4) is positioned.
Sealant (8) hermetically seals the central panel (4) to the rim portion (2). A push-in closure C in the central panel (4) comprises a closure tab (10) severed from the panel (4) along line (11) except for a hinge portion (12) and has a peripheral free edge portion (14) in overlapping underlying relationship with an edge portion (15) of the central panel (4). A latch means (17) formed in the edge portion (14) and engaging the free edge of the edge portion (15) prevents unintended inward movement of the tab (10).
Sealant (18) hermetically seals the push-in closure C. An inwardly direct abutment (19) formed in the central panel (4) adjacent the closure C opposite the hinge portion (12) comprises a substantially vertical wall portion that defines an anchor point for the tip of the bowl of a spoon inserted in the opening formed in the central panel (4) by inward displacement of the closure C and prevents withdrawal of the spoon as the spoon is levered against the rim portion (2) to deform the central panel (4) and remove it from the rim portion (2). The position of the peripheral free edge portion (5) between the folded portions (F1 and F2) facilitates easier removal of the central panel (4) from the rim portion (2) with a less variable removal force than was required with prior art constructions.

Description

~ULL OPEN CAN ~ CLOSUR~
Field of the Invention:
This inve~tion relates to closures for containers, and more particularly to closures of the full-open end type in which substantially all of the end pa~el is removed when th~ closure is opened.
Backg~ound of_~he Inven~ion:
Most full-open ends currently in use include an end pa~el which is scored or w akened alo~g a line extending adjacent the rim of the e~d which is seamed to the can body. ~he use of scored end panels has a~ least two ma~or shortcomings. In the îrst place, the scoring operation cannot be closely controlled to the extent ~ecessary to ~chieve easy rupture for end removal whilst preventing perforation o~ the end panel to avoid 12akage of con~ents from the can or leakage of air into the canO It will be apprecia~ed tha~ the:leakage of air i~to a can may have serious consequences in~the case of food products, a~d ~ay spoil other canned products.
In ~he second ;place, scored end pa~ls of the above descr~bed t ~ e leave sharp edges on the retained edge portio~ of the~end panel and:on the edge of the removed di~c. These sharp edges present a risk in that the fingers of the user may be cut handling the ca~ or ~he rc~oved disc a~ter opening.
While the latter problem may be reduced by the~for~ation of comple~ mul~iple~ folds~;in the:pa~el edge structure wh~h serve to protect the: raw~ edges after ~o~ening, this increases manufacturing ~d::~aterial costs and does ~ot address ~he first defe~t ~escribed above.~ : Exa~ples:of ~ypicaI full-op~n end clGsur~s of the above t ~ çs may be found i~ the Patent literature. It will be~oted that clos~res of ~his type require ,, a retained lever mechanism by mea~s of which the initial rupt~ring of the sco~e line i5 achieved, the lever mec~anism usually having a:fi~ger opening by means of ~hich the opening disc may be removed from the end pa~el. Such openi~g devices are often extremely difficult to manipulate a~d require a considerabl~ force to be applied to cause the initial rupturing of the score li~e. Such manipulation is often difficult to ~i ,~
,,j .

. .

~1~3338 ~ ,. ; 2 achie~e, particularly for a woman or child.
The Patent literature contains limited examples le-g. U.S.
Patent 4003495 and EPO 377788A) of full-open end closures which utilize readily available domestic implements, such as spcons, as levers to assist in opening the end panel. In the first of the above examples, the removal end panel is formed with a push-in end closure through which a spoon may be inserted to lever the end panel upwardly to break the tear line de~ining the removable panel. The tear line is defi~ed in this example as being formed by shear-co~ning and swaging a convex surface o~ the can end.
As ar as the present applicant is aware, this process has not been com~ercially adopt~d by the can making industry, and it is expected that the process involved in forming the tear line would be difficult to consistently perform in practice to ensure a consistent opening ~orce while avoiding rupture of the closure under the high pressures to which cans of food are s~bjected during the processing of ca~ned food products.
The second of the abo~e examples utilizes a ~eakenin~ line in the form of a ~-shaped ~i~k, and the spoon is described as engaging an external groove formed in ~he e~d to rupture the score and lever the panel from the end. .Experi~ents conducted pri~r to the present inven~ion caused the applicant tv abandon the use of scor~d~panels on the ground that it is too difficult to rupture the score line using a spoon as a lever, especially where ~he e~d is made: from st~el. In any even~, this constructio~ has the~same problems of ~ariable opening force and penetrati~ of the:end panel by the score line referred to above.
It wi1l be appreciated that if the opening force was ~oo high, ~h~ co~struction ~escribed would suffer from the problem of the spoo~ tip te~ding to slip from the groove during attempts to .. .. . . . . .
i`~ rupture the score line. Once again, as far as the applicant is ~ : aware, this construction has not found its way into commercial ,., ` production.
~ Summary of I~vention and Obie_t:
.-`. It~is a~ object of the present inven*ion to provide an `~ i~proved full-open d osure for a contalner member, such as a ~an ~ end, in which the above described problems are at least .~
.,.~;
:...
..:
. .

WO93/01096 . PCT/AU92/00337 ameliorated.
The invention therefore provides a closure for a container member, such as a can end, comprising a panel formed with a rim portîon and a central panel adapted for at least substantial removal from the rim portion, said central panel being at le~st substantially fully severed from said rim portion and having a peripheral free edge portion, said rim por~ion having a f irst fold defi~ing a~ inner free ed~e portion and a second oppositely directed fold defining an edge portion which extends in a spaced generally parallel relationship with said i~ner free edge portion, said peripheral ~ree edge portion o~ said central panel being positioned in overlapping relationship with and between said inner free edg~ portion and said parallel edge portion to prevent ~ispl~cement of said central panel outwardly or inwardly of said rim portio~ during processing and handling, sealant means hermetically sealing said peripheral edge portion of said central panel with respect to said rim portion,and ~eans associated with said central panel for enabling said central panel to be de4Ormed to disengage it fro~ its overlapping relatio~ship with said rim portion to remove said central panel from said rim portion.
Since the central panel is at least subsga~tially fully severed fro~ the rim portion, the severed free edges of the central panel and the ~im portion can be for~ed so as to sub:stanti~l~y reduce the likelihood of sharp edges. It is pvssible to co~trol the severing operation to produce resultant free edge por~ions which are essentially burr~free or blunt whereby the second probl~m associated with scored-structures is avoided.:Since th~ central panel is hermetically sealed with respect to the ~im portion,~ the leakage problems referred to above are either avoided or are relatively easy to detect during the manufacturing process.
Since ~he centra} panel is in overlapping rzlationship with the rim portion, the closure is able to withstand the high pressures to which canned foods are normally subjected during the cooking/sterilizing processes which are commonly used in the canned food industry.
In ~ preferred form of the invention described in greater A, ' ' :~

WO93/01096 PCT/~U92/00337 2113338~

detail below, the second oppositely directed fold i~ positioned in underlying relationship with said inner free edge portion and said peripheral free edgP portion of said central panel is positioned in overlapping and underlying relationship with said inner ~ree edge portio~ and in overlapping overlying re~a~ionship with said parallel edge portion. The advantage of this construction is that the free edge of the parallel edge portion can be hidden under the inner free edge portion and the sealant means is applied to the hidden inner face of the col1tainer member.
In view of the practical importance of ensuring tha~ the central panel is hermetically sealed with respect to the rim portion, it is preferred to construct the closure so that the peripheral free edge portion of the central panel is positioned to provide a gap between at least the parallel edge portion and the peripheral free edge portion to facilitate entry of sealant mater~al.
The closure is mos~ preferably constructed to position said peripheral free edge por~ion substantially centrally between *he inner ~ree edge portion an~ the spaced generally parallPl edge portion ormea by~ the first a~d second folds, to assist the sealant mea~s adequately penetrating:at least the overlappi~g portions o the peripheral free edge portion and the spaced parallel edge portion : ~efined by the secossd:~ fs~ld. In a particularly pre~erred form o~ the iIlventior~, the peripheral free edge portion ~ of - the :: central panel is formea with upwardly and dow~wardly projecting~ raised portions which are adapted to engage the inner free e~lge portion and ~he spaced parallel eage por~ion to substan1tially centralize ~the peripheral free ed~e portion betw~3en theE;e edge por~ions. One convenienlt way of achievi~g this co~struction is to formi spaced pairs o oppositely directed imples in the peripheral free edge portion of the central panel.
plthough it is preferred that the central panel should be Eully severed from the rim portion of the container member, some uses of the end closure may reqlaire the central panel to be retained to the rim portion by a narrow neck of met~l constituting a hinge about which the central panel may be bent , .i:
- .

WO93/01096 PCr/AU92/00337 21133~
. s ~o open the end closure. Furthermore, the central panel may remain connected to *he rim portion during the necessary ~etal forming operations by means of several narrow easily ruptured metal bridges which are broken when the panel is deformed duriny the implement l~vering operation.
The ~ea~s as~ociated with the ce~tral panel ~ay comprise ring-pull device by means of which an openi~g fvrce is applied to the central panel~ For manufacturing ~nd enviro~mental reasons, the means preferably comprises a clo~ure formed in the central panel and shaped to be opened by and to receive an opening implement for levering engagement with the rim portion to thereby deform the central panel to disengage it from the rim portion.
The closure means formed in the central panel i5 preferably a push-in closure and may take any one of a number of differént forms, including a scored push-in closure or a fully severed closure of the ~ype described in our United States ~atents Nos.
3,759,206, 3,931,909 and 4,155,480~ A fully ~evered closure o~
this type is preferred, and although a scored closure may su~fer from the first difficulty outlined above, thi~ di~ficulty could ba overcome by the application of sealant~to the scored region, . Where a severed push-in closure is used~ it will comprise a tab portion severed ro~ the central panel ex~ep~ or a neck of metal d~fining a,hin~e and overlappi~g and underlyi~g the edge portion of the central pa~el surrouad~ng the opening crea~ed by the se~eri~g operation.:The push-in closure tab andjor the edge portion of the ~entral panel surrounding the opening is cold worked to produce~ ~he overlappi~g relationship either i~ the manner described in~the afor~entioned patents and/or by suita~le coi~ing operations known in the.art.~ , Where ~he:end closure is to be used in a container for prod~cts which create~a v~cuum within the.container, the push-in closure can be formed with latch miembers of the type described in : our co-pending International Patent Application No.
PCT/AU90/00108 ~(U.S. Pate~t Application Serial No. 768739) to prevent the external air pressure pushing the closure tab into the open positio~, and to make it evident that the closure has ,. . . ~' .'':i , ~ ,. . .

been opened or in some way tampered with.
The push-in closure member is preferably shaped to receive a suitable implement of the type which is likely to be available when the container is being ope~ed. In the case of a conta~ner for pet food, or some other food product, the most convenient implement is a spoon, and the closure member i5 most suitably shaped to receive the bowl of the spoon which is then levered against the rim o~ the container to defo~m the central panel and withdraw it from its underlying relationship with the rim portion.
In a further preferred form o~ the invention, the end is formed with an inwardly directed abutment or dimple located centrally of the or each closure and adjacent the edge portion surrounding the opening opposite the hinge. The dimple is preferably dimensioned to provide an anchor point for the tip of tha bowl of a spoon, or other implement, inser~ed in the opening, to reduce the likelihood of the implement withdrawing from the opening as it is levered against the rim. In this way, the spoon or other implement operates securely to lever the central panel from its rim portion.
: Brief DescriPtion of the Drawinq~:
In order that the invention may be more readily understood, a prssently preferred embodiment of the in~ention w;ll now be . descri~ed with reference to the:accompanylng drawings in which:
Figure 1 is a plan ~iew of a can end embodying the invention;
:Figure 2 is a fra~men*ary sectional elevation of the can end take~ alQng the line 2 ~ in Fig. l;
igure 3 is an enlarged fra~mentary sectional elevation o the closure formations shown in Fig. 2;
~ : ~ Figure 4 illustrates one method of ope~ing the can end of i Figs.:l ~o 3. :.
Figures 5A to 5G illustrate the steps involved in one method ~ ~ of orming the can end embodying the inYention, and a fragmentary `~ sectional elevation of an altern~tive closure construction embodying the invention.
,~

' 1 '.J
,~, .

WO93/OlOg6 PCT/~U92/00337 ,i ~ .

Descri~tio~ of ~referred Embodiments:
Referring ~irstly to Figures 1 and 2 of the drawings, the can end 1 embodying the inventio~ comprises a ri~ portion ~
having an inwardly directed or inner free edge portion 3 and a central panel 4 having a peripheral free ~dg~ portion 5, which has been fully severed from the rim portion 2, d~spo~ed in overlapping and underlying relationship with the ~ree edge portiGn 3 of the rim portion 2.
The inner ~ree edge portion 3 of the in~er portion 2 is defined by a first underlying folded portion F" and a second spaced parallel folded portion F2 is formed in underlying relationship with the first folded portion F, and terminates in an edge E, positioned outwardly of the edge portion 3, to dein~
a continuous groove G within which the peripheral free edge portio~ 5 of the central panel 4 is receîved.
In a partiGularly preferred form o the invention~ the peripheral free edge portion S of the central panel 4 is ~or~ed with pairs of oppositely directed s~all dimples 6, 7 spaced equid~sta~tly a~ound the periphery of the free edge portion 5, as ~hown most clearly in Figure 1 of the dr wings. As will be evide~t from Figures 2 and 3 of the drawings, th~ di~ples 6, 7 cause the peripheral free ed~e portio~ 5 of the central panel 4 ~i; to be positioned:s~ stantially centrally between the folded ., portions Fl and F2. In this way, the sealant material 8 which is applied to the overlapping r~gions of the panel 4 ~d rim . ~ portion 2 is able to pe~etrate the region batween the peripheral j free edge po~tion-5 and at:least the folded portion F2 ~o e~sure th-~t a pro*er~hermetic se~al is form~d (see ~g~ 3)O
. ~ To ~:fur~her ensure that a proper volu~e of sealant 8 is retai~ed in the overlapping regions,. the central panel 4 is formed with a continuous downwardly extending rib 9 which creates : 2 barrier or reservoir which prevents movemient Qf the sealant 8 towards the centre of t~e central panel 4 when the ~ealant is applied to the end l by any suita~le method, such as that : descri~ed i~ further detail below.
~ he central panel 4 is formed with a push-in easy opening closure C omprising a downwardly dished closure tab 10 which is ~i :
i~i "
~l' . ., 2113338 ;:

fully se~ered from the panel 4 along line 11 to leave a hi~ge portion 12, a~d having a frae ed~e portion 14 disposed in overlapping and underlying relationship with an edge portion 15 surrounding the opening 16 created by the severing operating~ The closure C is formed, at free edge portio~ 14 of the closure tab 10, with spaced latch means 17 which frictionally engage the edge 11 of the edge portion 15 to inhibit movement of the tab 10 i~wardly of the panel 4 and/or to provide an indication of opening or tampering~ as shown most cl~arly in the enlarged sectional elevation of Figure 3. A sealant ma~erial 18 is applied to the overlapping regions sf the edge portions 14 and 15 to hermetically seal the closure C in the central panel 4.
The closure tab 10 is dished in the manner shown a~d the opening ~ is shaped to receive the tip the bowl B of a spoon S
in the ma~ner shown in Figure 4 of the drawings. The shape of the opening 16 has also b~en designed to relieve pcints of wea~ness in ~he design of the closure C when the can end 1 is sub~ected to internal pressure, when ~itted to a can, such as will occur when canned food products are processed for cooking and/or st~rilizing.
During the opening opera$ion, the bowl B of the spoon S is forced into the dished closure tab 10, forcin~ the tab 10 open past the~latch mea~s 17, breaking the sealant 15 a~d bending th tab 10 about ~he hinge 12, all ae shown in Fi~ure 4 of the drawings. : .
: To e~sure that ~he bowl B of the spoo~ S, or other similar implement, is maintai~ed in the opening 16 during the levering operation necessary to remove the central pa~el 4 from the rim portio~ 2, the central panel has an inwardly directed abutment or dimple 19 formed in the central panel 4 centrally of the closu~ C opposite the hinge 12 and adjacent the edge portion 11 surrounding the opening 16 o~ the closure C. The dimple 19 is shaped to provide a vertical rear wall 20, and is dimensioned to be received in the tip portion Df the bowl B, as shown in Fig.
4, with the wall 20 defining an adequate anchor point for the tip of the bowl B inserted in the opening 16 as it is levered against the rim 2, in the manner shown clearly in Figure 4 of the . ~ .
:~, ,, WO93/0109~ PCT/AU92/00337 211333~
g drawings, to deform the end panel 4 and r~move the frea edge portio~, 5 o~ the pane~ 4 from its underlyin~ r~lationship with the free edge portion 3 of the rim portion 2. The anchor point provided by the dimple 19 operates to prevent the bowl ~ of the spoon S withdrawing from the ope~i~g 10 as the æpoon S.i~ levered against the rim 20 It will be appreciated that without the dimple 19, the spoon may have a tenden~y to slide against the underside of the ce~tral panel 4 without adequately de~orming the central panel 4 to facilitate removal of the panel from the rim. A similar tendency would be present in the case of the construction described in prior U.S. Patent 4003495, in which the rim of the bowl of the spoon engages the portion 32 which extends around the periphery o~ the closure 28 thereby creating extrenely narrow frictional contact points between the~bowl and the pa~el 16~ In the present embodi~ent, the dimple lg operates to inhibit relative sliding movement betwe2n the spoon S and *he ce~tral panel 4 to ensure that the central panel 4 is properly defor~ed to allo~ its removal froM the rim 2.
As described abo~e, both the central panel 4 and the closure tab 10 are her~etically sealed with respect to the rim portion 2 ~nd the edge portion 15 re~pectively by means o~ the appliaation of sealant:12 and 18, such as a suitab~e pla~tisol, appli~d in a~y sùitable~manner known in the art, such a~ by an apparatus of the type~described in our United States Patents Nos.
4102304~ 4151314 and~4842469.
.~
The above desor~bed closures are ormed by suitable metal ~ worklng operation~ kn~n in the art, for exanple as j~ schenatically illustrated in ~igures 5A to SG of ~he arawings.
'~ Figure 5A shows a! typical can end shell on which the metal working operations necessary to form the above described closures - are performed. In Figure 5B, the end shell is reformed to have a su~stantially vertical rim ~all and the sealant retainin~ rib 9 is formed along with a central panel configuration which allo~s :: for expansion und~r internal pressure during canned food , 1 ~
processing. It is also preferred that the dimples 6 and 7 are formed in the moaified end shell, althol~gh they may alternatively . ~
~.i .;

, .

WO93/01~96 PCT/AU92/00337 . ~! ! ?
~113338 lo be formed in a subsequent operation before the next step.
The next step is shown in Figure 5C a~d compr~ses shearing the central pa~el 4 from the rim portion 2. The left side of Figure SC shows the position of the sheared el~ments at the bot*om stroke of the die operation, while the right side Gf Figure SC shows the position at the upstroke of the die operation. As mentioned above, the shearing operation is performed so as to produce essentially burr-free or blunt free edges to thereby avoid the problems associated with sharp or jagged edges of the type produced when scored metal is severed.

The previously substanti~lly vertical side wall o~ the rim 2 is formed with an inwardly directed bend which constitutes the commencement of the fold F~, the $old F2 already having been partially formed by the bend in the panel at the bottom of the vertical side wall. If desired the side wall of the end shell may have a commencement of the first fold F, preformed by a rolling operation during or immediately after the formation of the curled .~: edge i~ the edge portion 2, for example, as par* of the commencem~t ring ourling operation. This preforming operation assists the fold fo ~ ation referred to above.
I~ Figure 5~ ~he size of ~he cen~ral panel is expanded by reducing~the angle of the portion between the free edge portion and the remainder: of the central panel 4, and the folded portio~ F1 is further formed by collapsing the side wall of the r~m 2:about th~ existing bends.
: In ~igure SE, the double fold Fl, F2 has been flatte~ea into i: its:final form to capture the peripheral free edg~ portion 5, and : in Figurs SF the closure tab 10 is severed along the line 11, the lat~h ~eans 17 are formed in the ~ree edge portion 16 of the tab .~ ~
i~ 10 and th~ spoon engaging dimple 19 is formed. ln the final .~ ` i working opsration o~ Figure 5G, the tab 10 is coined to cause the free edge portion 14 to overlap and underly the free edge portion ~, ~.~ 15 and the latch means 17 to frictionally engage the edge of the .: .
~; ~ opening 11. Sealant is ~h~n applied to the end at 8 and 18 and ::: any nece~sary repair lacquer may also be applied to the exposed ~ ~ worked areas of the end 1.

i'`,'`, ~

.,'~
.;

WO93tO10g6 PCT/AU92/00337 While the embodiment shown în Figures 1 to 5 has the folded portionsr Fl, F2 of th~ rim portion 2 located below the free edge portion 3, it may be acceptable in certain applications for the folded portions F" F2 to be disposed above the free edge portion 3, in the general manner shown schematically in Figure 6 of the drawings. In such an arrangement, the sealant shown protects ~he sheared edge of the rim portion 2 again~t corrosion, and ~hile the free edge is exposed, it~ generally blunt configuration will prevent any serious risk of injury to the usex.
The central panel 4 may be formed in a~y de~ired profile, s~ch as shown in the drawings, to allow the central panel 4 to flex outwardly and inwardly during internal pressure changes cause~ by processing of the contents of the can. The profile of the central panel 4 may also be designed in a mannex not shown to facilitate deformation of the central pa~el 4 along particular lînes to faci~itate easy removal of the central panel 4 ~rom the rim portion 2. ~ ~ ~
Furthermore, the central panel 4 may be formed so that the panel is upwardly do~e~ in its related state. In this way, loss of vacuu~ or more:~accurately, leakage of ~ir into the can, may be ~isually detected. : ~ :
While in the~above described gmbodiments, the sealant S is applied-externally~after the closure has been ormed, ;t will be appreciated that sealant material could;be applied to portions of the:rim 2 ~o that~the:free~edge por~ion 5 of the ce~ral panel 4 is:~ cl~mped between:;:s~alant covered sur~aces to form the ne~essary her~etic~sea1~or:to orm a~further seal in addition to the ~ealant applied:as described above.
;- W~i1e~the~c1Osure 10 is dished in~the embodiment shown, it can alternatively~be essentially flat with an upsta~ding bend ar~und the free edge portion 14 to assist in the fo~mation df the 1atches 17 and~to~provide a~ engagement point for the spoon S
d~r~ng the opening operation.

.
~?, ~.

Claims

12

1. A closure for a container member, such as a can end, comprising a rim portion and a central panel adapted for at least substantial removal from the rim portion, said central panel being at least substantially fully severed from said rim portion and having a peripheral free edge portion, said rim portion having a first fold defining an inner free edge portion and a second oppositely directed fold defining an edge portion which extends in a spaced generally parallel relationship with said inner free edge portion, said peripheral free edge portion of said central panel being positioned in overlapping relationship with and between said inner free edge portion and said parallel edge portion to prevent displacement of said central panel outwardly or inwardly of said rim portion during processing and handling, sealant means hermetically sealing said peripheral edge portion of said central panel with respect to said rim portion, and means associated with said central panel for enabling said central panel to be deformed to disengage it from its overlapping relationship with said rim portion to remove said central panel from said rim portion.

2. The closure of claim 1, wherein the second oppositely directed fold is positioned in underlying relationship with said inner free edge portion and said peripheral free edge portion of said central panel is positioned in overlapping and underlying relationship with said inner free edge portion and in overlapping overlying relationship with said parallel edge portion.

3. The closure of claim 1 or 2, wherein the overlapping portions of said rim portion and said peripheral free edge portion are constructed to position said peripheral free edge portion to provide a gap between at least said parallel edge portion and said peripheral free edge portion to facilitate the penetration of sealant means into said gap.

4. The closure of claim 3, wherein said overlapping portions of said rim portion and said peripheral free edge portion are constructed to position said peripheral free edge portion substantially centrally between said inner free edge portion and said parallel edge portion.

5. The closure of claim 3 or 4, wherein said positioning of said peripheral free edge portion is provided by projections extending from at least one of said parallel edge portion, said peripheral free edge portion and said inner free edge portion.

6. The closure of claim 5, comprising pairs of projections extending from opposite faces of said peripheral free edge portion, said pairs of projections being spaced about the periphery of said peripheral free edge portion to substantially centrally position said peripheral free edge portion between said folded portions.

7. The closure of any preceding claim further comprising means associated with said central panel to retain the sealant means in the region of said overlapping portions of said rim portion and said peripheral free edge portion.

8. The closure of claim 7 wherein said sealant retaining means comprises a downwardly directed peripheral rib formed in said central panel inwardly of and adjacent said peripheral free edge portion, said rib extending to a position below said parallel edge portion.

9. The closure of any preceeding claim, wherein the means associated with said central panel comprises a closure formed in said central panel adjacent said rim portion and shaped to be opened by and to receive an opening implement for levering engagement with said rim portion to deform the central panel and facilitate its disengagement from said rim portion.

10. The closure of claim 8, wherein said closure in said central panel comprises a push-in closure shaped to receive said opening implement under said central panel.

11. The closure of claim 10, wherein said push-in closure comprises a severed closure tab having a free edge portion in overlapping and underlying relationship with said central panel and an unsevered portion defining a hinge about which said tab is bent when said push-in closure tab is opened, and sealant means hermetically sealing said closure tab with respect to said central panel.

12. The closure of claim 11, further comprising latch means formed in said free edge portion of said closure tab and frictionally engaging said central panel to inhibit unintended opening movement of said closure tab.

13. The closure of any one of claims 10 to 12, wherein said push-in closure is shaped to receive the bowl of a spoon which is levered against the rim portion to deform and remove said central panel from said rim portion.

14. The closure of claim 13, further comprising an inwardly directed abutment formed in said central panel adjacent said push-in closure, said abutment being shaped and positioned to serve as an anchor point for the bowl of the spoon to inhibit withdrawal of the spoon from engagement with the central panel during the levering operation.

15. The closure of claim 14, wherein said abutment comprises an inwardly directed dimple in the central panel closely adjacent the push-in closure, said dimple having a substantially vertical rear wall portion against which the tip of the bowl of the spoon engages to prevent withdrawal of the spoon from the push-in closure,

16. A method of forming a closure in a container member, such as a can end, comprising a rim portion and a central panel adapted for at least substantial removal from said rim portion, comprising the steps of substantially severing said central panel from said rim portion, forming a first fold in said rim portion to define an inner free edge portion and a second oppositely directed fold to define an edge portion which extends in a spaced generally parallel relationship with said inner free edge portion, expanding said central panel to locate a peripheral free edge portion thereof in overlapping relationship between said inner free edge portion and said parallel edge portion, and applying sealant means in the region of said overlapping portions to hermetically seal the peripheral free edge portion with respect to said rim portion.

17. The method of claim 16, further comprising the step of maintaining a gap between said peripheral free edge portion and at least said parallel edge portion to facilitate the penetration of sealant means into said gap.

18. The method of claim 17, comprising the step of forming peripherally spaced abutments extending from at least one face of said peripheral free edge portion to create said gap.

19. The method of claim 17 comprising the step of forming abutments extending from opposite faces of said peripheral free edge portion to position said peripheral free edge portion substantially centrally of said inner free edge portion and said parallel edge portion.

20. The method of any one of claims 16 to 19, further comprising the step of forming a push-in closure in said central panel adjacent said rim portion.

21. The method of claim 20, further comprising the step of forming an inwardly directed abutment adjacent said push-in closure, said abutment being positioned and shaped to be engaged by the tip of the bowl of a spoon inserted through said push-in closure to prevent withdrawal of said spoon from said closure when said spoon is levered against said rim portion to deform said central panel and remove it from said rim portion.