US3780902A

US3780902A - Container end closure

Info

Publication number: US3780902A
Application number: US00244777A
Authority: US
Inventors: H Holc; B Pillnik
Original assignee: American Can Co
Current assignee: Rexam Beverage Can Co
Priority date: 1972-04-17
Filing date: 1972-04-17
Publication date: 1973-12-25
Anticipated expiration: 1990-12-25
Also published as: FR2180861A1; FR2180861B1; BR7302576D0; CA994260A; BR7302777D0; JPS4930371U; JPS5422530Y2

Abstract

In a container subjected to internal pressure, a metallic end closure is provided having a central panel portion, a removable portion defined by a score line included in the central panel portion, and an opening tab attached to the removable portion proximate the periphery of the central panel portion, the pull ring or handle of the opening tab being radially inward from the point of attachment of the opening tab to the removable portion. The end closure is additionally provided with means on said central panel portion for releasably holding said opening tab substantially flat against said central panel portion when the central panel portion bulges outwardly due to the internal pressure of the container.

Description

v United States Patent [191.

Hole et al.

[111 3,780,202 Dec. 25, 1973 CONTAINER END CLOSURE [73] Assignee: American Can Company,

Greenwich, Conn.

22 Filed: Apr. 17, 1972 211 App]. No.: 244,777

[52] US. Cl. 220/54 [51] Int. Cl 865d l7/20 [58] Field of Search 220/54, 27, 48

[56] References Cited UNITED STATES PATENTS 3,593,875 7/l97l Fraze .r 220/54 Primary ExamineF-George T. Hall Att0rney-Robert P. Auber et al.

[ 5 7 ABSTRACT In a container subjected to internal pressure, a metallic end closure is provided having a central panel portion, a removable portion defined by a score line included in the central panel portion, and an opening tab attached to the removable portion proximate the periphery of the central panel portion, the pull ring or handle of the opening tab being radially inward from the point of attachment of the opening tab to the removable portion. The end closure is additionally provided with means on said central panel portion for releasably holding said opening tab substantially flat against said central panel portion when the central panel portion bulges outwardly due to the internal pressure of the container.

15 Claims, 5 Drawing Figures PATENIEDDECZS I975 Y 3.780.902

PIC-3.3 6 FIG.5

, l CONTAINER END CLOSURE The present invention relates generally to metallic end closures for easy opening containers. More specifically, the present invention relates to an improved metallic end closure for easy opening containers of the type having an opening tab attached to a removable portion of the end closure.

One of the basic developments in the container making industry was the development of the scored end for an easy opening container, opened by means ofa lifting force exerted on an opening tab secured to the removable portion of the end defined by the score. The most common form of such containers are the beer and beverage cans in which the removable portion defines a comparatively small opening through which the contents are dispensed when the removable portion is removed from the end closure. In another form of easy opening container the score line is formed proximate to the periphery of the central panel of'the end closure to permit the substantially complete removal of the central panel. This latter form of container is generally termed the full-open" container and is suitable for use in the packaging of solid-like or chunk-like products, such as processed foods, which are to be removed from the container in their entirety. The opening tab for such a full open container is usually attached to the removable portion at a point near the score line, the pull ring or handle being radially inward from the point of at- I tachment of the opening tab to the removable portion.

The point of attachment of the opening tab on end closures having comparatively small removable portions may also be proximate to the periphery of the end with the pull ring radially inward from the point of attachment. Thus, when the user desires to open the container, the pull ring or handle is grasped and lifted upwardly causing the nose portion of the tab, which acts as a stress concentrator, to initially break or pop the scored section adjacent to it. A pulling force is then exerted on the pull ring to continue tearing along the score line thereby removing the removable portion from the end. In the case of containers which require sterilization subsequent to the canning operation, the central panel of the'end closure has a tendency to bulge outwardly due to the internal pressure of the container resulting from the sterilization process. This outward bulging of the central panel of the end closure to which the opening tab is attached causes the free end of the tab, which is radially inward from the point of attachment of the tab to the central panel, to lift away from the central panel of the end closure. Since the free end of the opening tab of this type of container, which coincides with the pull ring or handle of the tab, does not lie flat against the central panel of the end closure, there exists the possibility that the pull ring could be inadvertently dislodged causing premature opening of the container during the processing and transportation thereof.

It is, therefore, a primary object of the present invention to provide an improved end closure for an easy opening container, wherein the opening tab is attached to the central panel of the end closure proximate the periphery thereof and tehe pull ring is radially inward from this point of attachment, which eliminates in whole or in part the possibility of accidentally opening the container owing to the lifted free end of the opening tab.

According to the present invention, this object, and others which will become apparent, is accomplished by providing an end closure of the type having a central panel portion, a removable portion defined by a score line included in said central panel portion, and an opening tab attached to said removable portion proximate to the periphery of the central panel portion, the pull ring or handle of the opening tab being radially inward from the point of attachment of the tab to the removable portion, with means for releasably holding the opening tab substantially flat against the central panel portion when the central panel portion bulges outwardly due to the internal pressure of the container.

The present invention will be described and understood more readily when considered with the embodiments of the accompanying drawings, in which:

FIG. 1 is a plan view of a container end closure according to the present invention;

FIG. 2 is an enlarged partial cross-sectional view of the end closure of FIG. 1 taken along line 2-2 of FIG.

FIG. 3 is a plan view of the opening tab of the end closure of FIG. 1;

FIG. 4 is a plan view of a modified form of the end closure of FIG. 1; and

FIG. 5 is an enlarged partial cross-sectional view of the end closure of FIG. 4 taken along line 55 of FIG.

Now referring to the drawings, there is shown in FIG. 1 an end closure, generally designated 10, for an easy opening container of the full-open end type. End closure 10 maybe circular and constructed of steel, aluminum, tin plate, plastic, or other suitable repturable material. As clearly seen, end closure 10 is formed'with a generally planar central panel portion, generally designated 12, which merges at its periphery with annular countersink wall 14. The upper end portion of wall 14 merges with outwardly extending curled flange 16 which may be interfolded with the end flange of a container body (not shown) to form an end seam (not shown).

Included in central panel 12 is a removable portion, generally designated 18, which is defined by and included within score line 20. Removable portion 18 becomes detached from end closure 10 when score 20 is completely ruptured. The entire length of score line 20 may be proximate to the periphery of central panel 12 thereby making removable portion 18 substantially coextensive with the central panel.

In order to rupture score 20 and detach removable portion 18 from end closure 10, an opening tab,.generally designated 22, is provided. Opening tab 22 is attached to the removable portion proximate the periphery of central panel 12 by a suitable securing means such as hollow rivet 24 which may be integral with and formed in removable portion 18.

As clearly seen, opening tab 22 includes 'a web portion 26, a handle portion or pull ring 28 attached to web portion 26, and a stress concentrating nose portion 30 formed in web portion 26 and oppositely disposed from pull ring 28. Opening 32 is provided in web portion 26 for the purpose of accepting rivet 24 for the attachment of opening tab 22 to removable portion 18. In this manner rivet 24 functions as a fulcrum for opening tab 22 such that when pull ring 28 is'lifted upwardly tab 22 pivots about rivet 24 causing nose portion 30 to contact score line 20 and concentrate the stress at the point of contact thereby breaking the score. Handle portion or pull ring 28, although shown in the drawings as being in the form of a ring may have any suitable shape or configuration desired, such as rectangular, triangular, etc. The handle portion is adapted for ease of grasping by the user, such as by the insertion through the ring of at least one of the users fingers. A flattened portion, generally designated 34, may be provided at that portion of pull ring 28 which is to be initially lifted by the user for the purpose of permitting easier insertion of the users finger. Inwardly angularly flattened portions, generally designated 36 and 38, of pull ring 28 are provided having inwardly extending arcuate projections, respectively designated 40 and 42, as most clearly seen in FIG. 3.

As hereinbefore noted with respect to containers which are sterilized subsequent to the canning operation, the central panel of the end closure tends to bulge outwardly due to the internal pressure within the container resulting from the sterilization process. Such a condition is most clearly depicted in FIG. 2 where central panel 12 is arcuate in shape having the smallest deflection at its periphery and the maximum deflection at its center.

Since the point of attachment of opening tab 22 is proximate to the periphery of central panel 12, where a small amount of end deflection occurs, the free portion of tab 22 which is radially inward from rivet 24 would be displaced upwardly with respect to central panel 12. In order to prevent'this upward displacement of the free portion of opening tab 22,

protuberances

44 and 46 are provided on central panel 12.

P rotuberances

44 and 46 are so positioned that they lie within pull ring 28 adjacent the inner edge 48 of the pull ring and proximate to the

flattened portions

36 and 38 thereof. The sides of

protuberances

44 and 46

adjacent projections

40 and 42 are substantially flat with the upper portions thereof extending slightly over

projections

40 and 42 when pull ring 28 lies flat against central panel 12, as clearly seen in FIG. 2. Due to the arcuate shape of

projections

40 and 42 there results a point contact between the projections and the respective protuberances which permits the pull ring to be disengaged from 'the protuberances with relative ease.

Protuberances

44 and 46 may be formed in central panel 12 by suitable dimple forming dies simultaneously with the formation of rivet 24 and are preferably hemispherical in shape. The flattened sides of

protuberances

44 and 46 are formed by flattening the portions thereof with suitable dies and due to the spring back of the stretched upper portions of the protuberances these upper portions extend outwardly over the flattened sides when the die is removed.

A slightly modified form of the present invention is seen in FIGS. 4 and 5 where the reference numerals indicating parts similar to the parts designated in FIGS. 1-3 are preceded by the numeral 1. The difference between the embodiments lies in the shape of the respective protuberances. As clearlyseen in the

drawings protuberances

144 and 146 are formed similarly to

protuberances

44 and 46 with the added feature that they are angularly flattened at 150 and 152 thereby resulting in a greater overlapping of pull ring 128.

It is understood that the foregoing general and detailed descriptions are explanatory of the present invention and are not to be interpreted as restrictive of the scope of the following claims. 3

'What is claimed is:

1. An improved end closure for a container subjected to internal pressure of the type having a central panel portion, a removable portion defined by a score line included in said central panel portion, and an opening tab including a pull ring attached to said removable portion for removal thereof by the user, the point of attachment of said opening tab to said removable portion being proximate the periphery of said central panel portion with the pull ring of said opening tab radially inward from the point of attachment, wherein the improvement comprises means on said central panel portion releasably engaging the pull ring of said opening tab to thereby hold said opening tab substantially flat against said central panel portion when said central panel portion bulges outwardly due to the internal pressure of the container. 2. The improved end closure as defined in claim 17 wherein the means for releasably engaging the pull ring of said opening tab comprises at least one protuberance on said central panel portion adjacent the pull ring of said opening tab, said protuberance having an upper portion which partially overlapps said pull ring when said pull ring is pressed onto said central panel portion thereby releasably holding said opening tab substantially flat against said central panel portion when said central panel portion bulges outwardly due to the internal pressure of the container.

3. The improved end closure as defined in claim 1 wherein the means for releasably engaging the pull ring of said opening tab comprises a first protuberance on said central panel portion adjacent the pull ring of said opening tab and a second protuberance on said central panel portion adjacent the pull ring of said opening tab, said first and second protuberances having upper portions which partially overlap said pull ring when said pull ring is pressed onto said central panel portion thereby releasably holding said opening tab substantially flat against said central panel portion when said central panel portion bulges outwardly due to the internal pressure of the container.

- 4. The improved end closure as defined in claim 3 wherein said first and second protuberances are so positioned on said central panel portion as to be within the pull ring of said opening tab.

5. The improved end closure as defined in claim 3 wherein said first and second protuberances are raised dimples on said central panel portion which protrude above the plane defined by said central panel portion. 6. The improved end closure as defined in claim 5 wherein said raised dimples are hemispherical in shape having the sides adjacent said p ull ring substantially flat.-

7. The improved end closure as defined in claim 6 wherein the portions of said pull ring adjacent the flat sides of said raised dimples are substantially flat having arcuate projections extending toward said dimples whereby point contact is made between said projections and the flat sides of said dimples when said pull ring is pressed onto said central panel portion.

8. The improved end closureas 'defined in claim '6 wherein said hemispherically shaped raised dimples are angularly flattened thereby extending the upper portions of the flat sides of the dimples partially over said pull ring.

9. The improved end closure as defined in claim 1 wherein said end clousre is metallic.

10. The improved end closure as defined in claim 1 wherein said end closure is plastic.

11. An end closure for a container subjected to internal pressure which comprises a central panel portion, a removable portion defined by a score line included in said central panel portion, an opening tab attached to said removable portion, the point of attachment of said opening tab to said removable portion being proximate to the periphery of said central panel portion, the pull ring of said opening tab being radially inward from the point of attachment of said opening tab to said removable portion, a first hemispherically shaped dimple on said central panel portion within the pull ring of said opening tab, and a second hemispherically shaped dimple on said central panel portion within the pull ring of said opening tab, the sides of said first and second dimples adjacent the inner edge of the pull ring being substantially flat and having upper portions extending slightly over said pull ring when said pull ring is pressed onto said central panel portion to thereby releasably engage the pull ring of said opening tab and releasably hold said opening tab substantially flat against said central panel portion when said central panel portion bulges outwardly due to the internal pressure of the container.

12. The end closure as defined in claim 11 wherein said removable portion defined by said score line is substantially co-extensive with said central panel porsaid end closure is plastic.

Claims

1. An improved end closure for a container subjected to internal pressure of the type having a central panel portion, a removable portion defined by a score line included in said central panel portion, and an opening tab including a pull ring attached to said removable portion for removal thereof by the user, the point of attachment of said opening tab to said removable portion being proximate the periphery of said central panel portion with the pull ring of said opening tab radially inward from the point of attachment, wherein the improvement comprises means on said cEntral panel portion releasably engaging the pull ring of said opening tab to thereby hold said opening tab substantially flat against said central panel portion when said central panel portion bulges outwardly due to the internal pressure of the container.

2. The improved end closure as defined in claim 17 wherein the means for releasably engaging the pull ring of said opening tab comprises at least one protuberance on said central panel portion adjacent the pull ring of said opening tab, said protuberance having an upper portion which partially overlapps said pull ring when said pull ring is pressed onto said central panel portion thereby releasably holding said opening tab substantially flat against said central panel portion when said central panel portion bulges outwardly due to the internal pressure of the container.

4. The improved end closure as defined in claim 3 wherein said first and second protuberances are so positioned on said central panel portion as to be within the pull ring of said opening tab.

5. The improved end closure as defined in claim 3 wherein said first and second protuberances are raised dimples on said central panel portion which protrude above the plane defined by said central panel portion.

6. The improved end closure as defined in claim 5 wherein said raised dimples are hemispherical in shape having the sides adjacent said pull ring substantially flat.

8. The improved end closure as defined in claim 6 wherein said hemispherically shaped raised dimples are angularly flattened thereby extending the upper portions of the flat sides of the dimples partially over said pull ring.

12. The end closure as defined in claim 11 wherein said removable portion defined by said score line is substantially co-extensive with said central panel portion.

13. The end closure as defined in claim 11 wherein said pull ring further comprises substantially flat portions adjacent the flat sides of said dimples and arcuate projections extending toward said dimples from said flat portions whereby point contact is made between said projections and the flat sides of said dimples.

14. The end closure as defined in claim 11 wherein said end closure is metallic.

15. The end closure as defined in claim 11 wherein said end closure is plastic.