CA1127568A - Can end closure - Google Patents

Can end closure

Info

Publication number
CA1127568A
CA1127568A CA361,775A CA361775A CA1127568A CA 1127568 A CA1127568 A CA 1127568A CA 361775 A CA361775 A CA 361775A CA 1127568 A CA1127568 A CA 1127568A
Authority
CA
Canada
Prior art keywords
tab
vent
central panel
closure
hinge
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA361,775A
Other languages
French (fr)
Inventor
Alfred H. Boardman
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Primerica Inc
Original Assignee
American Can Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by American Can Co filed Critical American Can Co
Priority to CA361,775A priority Critical patent/CA1127568A/en
Application granted granted Critical
Publication of CA1127568A publication Critical patent/CA1127568A/en
Expired legal-status Critical Current

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  • Containers Opened By Tearing Frangible Portions (AREA)
  • Closures For Containers (AREA)

Abstract

Docket No. 13,206 CAN END CLOSURE
Abstract of the Invention The instant invention relates to an end closure or cover for a metal container comprising a substantially flat sheet metal lid seamed about its extremity to the container body closing the body end. The lid has a pour opening having a closure hingeably connected to the lid and closing the pour opening provided to retain the closure against inward displacement thereby resisting atmospheric pressure and premature opening of the container and against outward displacement due to internal pressure during processing.

Description

5f~3 Background of the Invention The present invention relates generally to end closures for food and drink containers and more particularly to can end closures which have improved scoring in combination with easy opening features which are environmentally acceptable.
There has been a continuing demand for a lid construc-tion for such containers wh~ch may be opened without the need of separate opening devices. One such construction generally termed the "pull-tab", embodies a scored outline in the surface of the container lid and a supplemental pull ring attached to an end of the outline to facilitate tearing along the scored outline and lifting it from the can end. That construc-tion has several inherent disadvantages, one relates to the pos-sibility of minor injuries resulting from contact with the edges of the opening or of the discarded pull-tab. A further disadvantage of such construction relates to ecology, and in-volves the rather prevalent indifference as to the proper dis-posal of the detached tabs causing complaints of injury and litter and promoting legislation directed at the banning of such container closures. Similarly, the need to add the pull ring is costly and wasteful of material and energy.
Another type of can end constructions which has been proposed in recent years is the push-in tab type. An example of can end construction of this type can be found disclosed in ~.S. Patent No. 4,054,228 granted October 18, 1977 and the other prior art therein cited. Those prior patents disclose can open-ing arrangements which embody can ends having score lines, partial shearing and severing defining two inwardly-displace-able raised tab portions in the can end. The partial shear or severance leaves a residual wall section which is intended to break when the tab portion is depressed. Some prior art shows closures provided with two openings which are closed by ., - 1 - ~.

1~7S~i~

slugs stamped from the end panel and are secured to a peelable strip or tape. Nonedisclose an arrangement which is capable of retaining a vacuum and internal pressure.
The prior patent of Balocca et al (#4,054,228) is sin-gular in its recognition of the problem of using the aforesaid inwardly displaceable tabs with food and drink which are sub-ject to positive and negative pressure during packing and pro-cessing. More particularly, a vacuum results where a hermetic seal is required and generates a vacuum pack having atmospheric pressure greater than the internal pressure of the container.
The Balocca et al U.S. patent discloses a two sealant means to reinforce and hold the inwardly displaceable tabs against the force of atmospheric pressure. Such an approach was effective to a degree being limited as to the adhesive application con-sistency and strength of the sealants and the temperature to which the container could be raised during processing. The flexibility sought with respect to the desired vacuum retention by inwardly displaceable tabs is achieved by the present dis-closed scoring, shearing and coining of the inwardly displace-able tabs.
It is, therefore, a primary object of the present in-vention to provide an improved easy open can end closure with scoring and coining of the tabs to eliminate in whole or in part -the disadvantages inherent in the can and closures discussed above. More specifically, it is anobject of the invention to provide novel forming of the tabs for a can end closure having facile opening features which are ecologically advantageous.
Summary of the Disclosure The instant invention relates to a can end closure com-prising a double seamable rim and a central panel having a pouropening and a vent opening each being closed by associated inwardly displaceable tab portions formed from the material of llZ756B

the openings. Each tab is dimensioned and configured to close its opening. EIinge means secure each tab for controlled manu-ally displaceable mounting of the tabs to the end panel. The hinge means is a portion of unworked metal extending between the inwardly displaceable tab portion and the closure center panel from which each tab is formed. The basic elasticity of the metal provides the flexibility about a bending axis for the hinge means. Contiguous with the hinge means are scored~curvilinear lines which extend from the hinge axis ends outwardly and in generally opposite directions but curve until substantially parallel to and across from one another. The scored portions are continued and connected by completely severed portions which extend therefrom in a curvilinear fashion on a path which brings them together at a point opposite the hinge. During the form-ing of the lnwardly displaceable tab portions as defined by the scoring and the severed portions a marginal area on each tab opposite the hinge means is coined so as to be enlarged whereby it extends beneath the panel from which it was severed; such ex-tension acting to restrain movement outwardly of the panel.
The scored portion includes a cut to a depth which leaves .004 to .006 inches of stock remaining. The thickness of the panel is about 0.125 inches and so the metal which is un-severed and unscored acts as the interconnection to prevent the inward displacement of the tab when subjected to atmospheric pressure from above and less than atmospheric pressure inside the sealed container. The aforesaid interconnection is reliable and can be easily adapted to function with various packing pro-cedures no matter whether the internal pressure is great or small during the processing or subsequent.
Brief Description of the Drawings Fig. 1 is a top plan view of the end closure of the present invention showing the inwardly displaceable tab portions llZ7568 as they appear when in their closed or sealed positions;
Fig. 2 is a bottom plan view of the end closure of Fig.
1 and the polymeric sealant used to cover and seal the bottom of the inwardly displaceable tab portions has been removed in order to clearly illustrate the present invention;
Fig. 3 is an enlarged cross-section as taken along lines 3-3 of Fig. l;
Fig. 4 is an enlarged partial cross-section of the vent button tab portion to show the scoring, and Fig. 5 is an enlarged partial cross-section of the pour opening button tab portion to show the scoring.
Detailed Description of the Drawings Fig. 1 depicts the top plan view of an end closure of the type having an inwardly displaceable vent button tab portion 10 and an inwardly displaceable pour opening button tab portion 11 each being circular in shape and protruding upwardly with a hat-shaped cross-section. Each tab portion button 10 or 11 is adapted to be opened inwardly by a preset finger pressure applied from above, and each said button 10 and 11 is designed to be maintained as part of the central panel 12 of the end closure by means of the fabrication method used to produce them. The con-figuration of each button portion 10 and 11 is similar, whereby similar designations by reference numbers will be used.
Each tab portion 10 and 11 includes a hinge area 13 positioned along a diametric line across the end closure. Said hinge area being approximately 3/32 of an inch along the arcs of the circles which define the overall peripheral shapes of tab portions 10 and 11. The center of the circular portion 10 and 11 are also aligned along the aforesaid diametric line but are spaced apart fxom one another approximately at an equal distance from the center of the end closure central panel 12.

Fxtending out from the hinge area 13 are several scored arcuate , ~ - 4 -~lZ~6i~

curvilinear sections 14 which penetrate the metal to within .004 to .006" of completely shearing the metal of the end. More particularly, the end is fabricated from stock which is .0125" in thickness such that one-half to three-quarters of the total thickness is severed by the scoring 14. The score line 14 ex-tends from the hinge areas 13 in curvilinear fashion along the arc of the circle generally defining the vent and pour opening button tab portions 10 and 11 approximately half way around the circumference.
The extent (depth) and the length (extension) of the scoring 14 determines the exact resistance to opening of the tab portions 10 and 11. That is to say, that the restraint against opening is a function of the area scored for each button tab portion 10 and 11. However, the material from which the end is fabricated and the sealant also have a bearing upon the resis-tance to opening. A material which works well in the preferred embodiment of the end is an aluminum alloy designated by the industry as 5182 Hl9. This material has the requisite flexi-bility and resilience necessary to be used in connection with the manufacture of the end and its operation.
The configuration of the vent and pour opening buttons being hat-shaped and generally circular include a fully severed area 15 which defines the remaining part of the circular tab portions 10 and 11. The fully severed portion 15 is formed by ; shearing the peripheral area which extends along the circle forming the remaining arc of about 180 between the end of the scored lines 14 to complete the circle.
In Figs. 3, 4 and 5, a part of the hat-shape is shown and includes a generally upwardly extending wall 16 which inter-connects an annular rim 17 and a flat top part 18. In generat-ing the inwardly displaceable vent and pour opening tab portions 10 and 11, a progressive forming operation is used to first de-~,.

1127~i8 fine the circular hat-shaped configuration of portions 10 and 11. Those skilled in the art will appreciate that the hat-shaped tab portions 10 and 11 can be formed from a basic end having a rim for double seaming and a center panel by means of a conversion press with tooling and dies which stretch and bend the metal during multiple forming operations. Once the metal has been suitably contoured and includes the hat-shaped confi-gurations the end is finished by tooling which partially scores along lines 14 and pierces or severs along lines 15. The tab portions 10 and 11 are not completely formed since the severed parts defined by lines 15 requires further forming in order to make an overlapping section 19, see Figs. 3, 4 and 5.
More particularly, as best shown in Fig. 1, there is a coined arc 20 on tab portion 10 and a coined arc 21 on tab portion 11. It will be noted that coined arcs 20 and 21 appear as recessed areas of metal in Fig. 1. The force of coining causes the circumference of the tab portions 10 and 11 adjacent to the coining to extend radially outward relative to the center of said Portions 10 and 11. It is that extension which provides the overlapping configuration 19, as shown. It will be noted that the amount or length of coined arc 20 or 21 is different for the tab portions 10 and 11 as needed for greater or lesser retention against internal pressure. That is to say that the amount of overlapp~ng 19 necessary is a function of the area of the tab portions which is exposed to internal pressure. The vent button tab portion 10 being smaller in diameter and in overall area requires less overlap 19, than the pour opening button tab portion 11, however, to facilitate tooling arc 20 is longer than arc 21.
In certain applications it is also necessary to reform the hat-shaped section of the tab portions 10 and 11 in order to increase the amount of overlaPping 19. This reforming may be ' - 6 -7~6~3 done at the same time the coining 20 and 21 is done.
Fig. 3 shows the polymeric compound 22 in phanton which is added to the bottom in order to seal the severed portions along lines 15 of the tab portions 10 and 11. A suitable seal-ant, such as plastisol, is satisfactory for use in connection with protecting the cut edges and forming air-tight closures along lines 15. The sealant 22 is applied to form the donut-shape which acts to cover not only the severed lines 15 and the overlapping joints 19, but also the rest of the underside of the circumference of the vent and pour opening button tab por-tions 10 and 11. When manufactured as set forth, the vent button tab portion 10 requires approximately 8 pounds of force to be opened and the pour opening tab portion 11 requires 12 pounds to be opened.
For use, instructions may be embossed on the panel 12 surface of the end adjacent the tab portion 11 indicating that the pour opening must be pushed first. This is contrary to the usual arrangement wherein the vent opening is first pressed on containers having internal pressure such as beer and beverage.
More particularly, the vacuum helps to open the larger area tab portion 11 and, therefore, the preferred procedure is specified.
In use, the end as disclosed herein and shown in Figs.
1 through 5 is double seamed to a container which can be packed with a hot filled or a sceptically packed product and is either retorted or allowed to cool, The exact process will depend upon the nature of the product being packed. Milk pro-ducts or certain soups and the like re~uire processing which causes the hermetically sealed container to be pressurized during processing and depressurized after cooling. That is to say that, the end as described will have to resist internal pressures of 18 to 20 pounds per square inch during processing by means of the overlapping joint 19 and the polymeric sealant S~3 22 and -then during cooling and depressurizing of the contents and the gases in the head space above the contents in the con-tainer re~uire less volume whereby the vent and pour opening button tab portions 10 and 11 can be subjected to 15 inches of vacuum. The end as configured, has been tested and found to be capable of resisting as high as 30 inches of vacuum.
Those skilled in the art will appreciate the changes in material, in score length and depth and area of overlap can be made which will permit a variety of design parameters to be attained without substantial modification to the overall con-cept sought to be protected by the claims which follow.

Claims (11)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An end cover for a container comprising: a central panel having a pour opening and a closure tab therefore dimensioned and configured to close said pour opening, a hinge for connect-ing said closure tab to said central panel for mounting said closure tab for controlled displacement relative to said cen-tral panel about the axis of said hinge, scored lines defining at least a part of said tab configuration and extending from the ends of said hinge axis along the periphery of said closure tab for a predetermined distance to act as a restraint up to a preset force against inward movement of said closure tab, a severed line defining the remaining periphery of said tab and extending from said scored lines and interconnecting same and having a marginal portion formed to extend and engage said cen-tral panel to resist movement outwardly of said central panel when subjected to internal container pressure.
2. The end cover of claim 1 including a vent opening and a vent tab dimensioned and configured to close said vent opening, a vent hinge for mounting said vent tab to said central panel for arcuate inwardly displaceable movement relative to said panel about the axis of said vent hinges, scored lines for said vent defining at least a part of said vent tab and extending from the ends of said hinge axis along the periphery of said vent tab for a predetermined distance to act as a restraint up to a preset force against inward movement of said vent tab, a severed line for said vent defining the remaining periphery of said vent tab and extending from scored lines for said vent and intercon-necting same and having a marginal portion formed to extend and engage said central panel to resist movement outwardly of said central panel when subjected to internal container pressure.
3. The end cover of claim 2 including a sealing means applied to the bottom of the central panel about the periphery of said closure tabs.
4. The end cover of claim 3 wherein said sealing means is a polymeric material.
5. The end cover of claim 4 wherein said sealing means is a plastisol.
6. The end cover of claim 2 wherein said closure tabs are substantially circular in configuration and said score lines extend from said hinge substantially 180° about said periphery.
7. The end cover of claim 2 wherein said hinge is ap-proximately 3/32" along the periphery and is centered across the end diameter.
8. The end cover of claim 1 wherein said pour closure tab has a preset opening finger force of 12 pounds.
9. The end cover of claim 2 wherein said vent tab has a preset opening finger force of 8 pounds.
10. A method of forming a closure including inwardly displaceable tab portions for venting and pouring including the following steps: forming a generally circular container and hav-ing an outer rim adapted for double seaming to a container and a substantially flat circular central panel with outer and inner surfaces, reforming said central panel to include outwardly dis-placed hat-shaped sections of circular configuration with one of said sections being larger in diameter than the other, scoring to a depth which leaves .004 to .006" of material along approxi-mately half of the perimeter of the circle defining each said section and extending from an area which is unscored and unse-vered and remains a hinge having a circumferential length of about 3/32", severing the remaining semi-circular circumference of said sections to form a curvilinear cut line between the ends of said scoring away from said hinge, coining margins of each said severed hat-section in order to extend same beneath the adjacent central panel from which same was severed, and sealing the cut edge of said severed inwardly displaceable tab portions with a polymeric material applied to the inner part of said central panel and said margins.
11. A metal end closure for a container to be filled and sealed hermetically against internal and external pressure including a circular rim portion to be used for double seaming and a substantial flat central panel including large and small hat-shaped circular protruberances formed in said central panel and extending outwardly of said surface each of which close the container, hinges between said central panel and each of said hat-shaped protruberances being 3/32" long a portion of undis-turbed material located along the circumferential, scored lines extending away from said hinges and defining the periphery of at least one-half of each said protruberance each said line being cut into the metal to a depth of ,004 to .006" so that approxi-mately 30 to 50% of the metal thickness is cut, lines of sever-ance defining the remaining semi-circular peripheries of said hat-shaped protruberances being cut clear through the central panel, and marginal sections adjacent said remaining semi-circu-lar peripheries which are coined to form same in radially ex-tended fashion to fit beneath the area of the central panel from which said marginal sections were originally coined.
CA361,775A 1980-10-08 1980-10-08 Can end closure Expired CA1127568A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA361,775A CA1127568A (en) 1980-10-08 1980-10-08 Can end closure

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA361,775A CA1127568A (en) 1980-10-08 1980-10-08 Can end closure

Publications (1)

Publication Number Publication Date
CA1127568A true CA1127568A (en) 1982-07-13

Family

ID=4118086

Family Applications (1)

Application Number Title Priority Date Filing Date
CA361,775A Expired CA1127568A (en) 1980-10-08 1980-10-08 Can end closure

Country Status (1)

Country Link
CA (1) CA1127568A (en)

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