US3422983A

US3422983A - Tab-opening can

Info

Publication number: US3422983A
Application number: US623710A
Authority: US
Inventors: John Wilson Rouse
Original assignee: American Can Co
Current assignee: Primerica Inc
Priority date: 1967-03-16
Filing date: 1967-03-16
Publication date: 1969-01-21
Anticipated expiration: 1986-01-21
Also published as: JPS4940679B1; GB1210955A

Description

Jan. 21, 1969 J. w. ROUSE 3,422,983

TAB-OPENING CAN Filed March 16, 1967 Sheet of 2 f Z 16' 7d 712 .4

' h j'fll INVENTOR fall/V WILSON ROI/6E AGENT Jan. 21, 1969 J. w. ROUSE TAB-OPENING cm Filed March 16, 1967 Sheet INVENTOR JOHN W/LSGA/ HOUSE United States Patent 3,422,983 TAB-OPENING CAN John Wilson Rouse, Ramsey, N.J., assignor to American Can tlompany, New York, N.Y., a corporation of New Jersey Filed Mar. 16, 1967, Ser. No. 623,710

U.S. Cl. 220-54 Int. Cl. B65d 17/20 9 Claims ABSTRACT OF THE DISCLOSURE In an easy-opening can of the type wherein an opening tab is secured to a removable section defined by a principal score line, one or more auxiliary scores are impressed in the can near the point where the tear in the principal score is to be initiated to break away the removable section, the auxiliary scores functioning to reduce the force necessary to initiate the tear.

Background 0 the invention In this type of can, the removable section is defined by at least one weakening score which is impressed directly into the metal of a wall in the can and which may take any suitable shape. Thus, in containers designed to permit dispensing of liquids such as beer or soda, the score is usually shaped to provide a restricted opening which permits easy flow of the liquid, while in containers designed to contain solid products, the score comprises a tearing line which rims an entire panel of the can to permit complete removal of the panel to provide ready access to the contents.

In many such cans the opening ta-b generally takes the form of a rigid lever which is permanently secured to the can wall with a rivet which is formed integral with the removable section and passes through a small hole formed in one end of the tab, the portion of the tab remote from the riveted end being formed into a handle which is engageable by the fingers of the user, who first lifts the handle portion of the tab upwardly away from the can wall to thereby cause a part of the tab to exert a fulcruming force on the metal on one side of the score or on the score itself to initiate the rupture of the thinned metal in the score line at a location near the rivet. It has been found that a considerable force is necessary to initiate the breaking out of the removable section because the force exerted by the user is distributed over a considerable portion of the unruptured score line.

One way heretofore used to lessen the force required to remove such a removable section is to make the score line deeper in order to decrease the thickness of the residual metal at the bottom of the score. However, if the score is made deep enough to permit the user to initiate rupture therein easily, problems arise because the resultant weakness of the score makes it vulnerable to inadvertent rupture during shipment, storage and handling of the can. In addition, because of manufacturing variations, such scores may be initially made so deep that they crack open during manufacture.

The present invention overcomes these problems by making possible a substantial reduction in the force required to initiate the breaking out of a removable section 3,422,983 Patented Jan. 21, 1969 defined by a score line without the necessity of utilizing an excessively deep score. Specifically,-one or more auxiliary score lines, in addition to the principal one which defines the removable section, are impressed in the metal and located to lessen the force necessary to initiate the breaking out of the removable section in a manner which will presently be explained. The reasons why the auxiliary score lines reduce the force required to initiate rupture of the principal score is not completely understood, since these auxiliary scores themselves do not rupture, but in practice it has been found that the force required to rupture the principal score is substantially reduced when the auxiliary scores are used. As an example of the efficiency of the instant invention, the provision of the auxiliary score lines in one form of easy opening end has reduced the required initial lifting force (sometimes referred to as pop value because the initial breaking action usually results in a popping sound and motion) from three pounds to two pounds.

It is, therefore, an object of the present invention to provide an easy opening can having a removable portion defined by a score line having a depth consistent with the necessary abuse resistance of the can and which may be initially ruptured by the exertion of a minimum force.

Summary of the invention In accordance with the present invention, there is provided a component for a container, the component comprising a panel, a removable section in the panel defined by a principal score, an opening tab secured to the removable section, and operative upon manipulation to exert an opening force on a localized portion of the principal score, and one or more auxiliary scores at or near said 10- calized portion to lessen the lifting force which must be exerted on the opening tab by the consumer to initiate rupture of the principal score in said localized portion.

Brief description of the drawings FIG. 1 is a plan view of an end closure embodying the principals of the present invention;

FIG. 2 is an enlarged vertical section taken substantially along the line 22 of FIG. 1, this line 22 extending through the center line of the opening tab to the center of the attaching rivet and then extending partially along the center line of the scored removable section of the end closure;

FIG. 3 is an enlarged sectional view similar to that shown in FIG. 2, but showing the end closure seamed onto a can body which is filled with a product under pressure;

FIG. 4 is an enlarged vertical section of the portion of the end closure shown in FIG. 3 illustrating the position of the parts after the opening tab has been lifted to initiate rupture of the scored metal which defines the removable section of the end closure;

FIG. 5 is an enlarged vertical section of a portion of the present closure showing the position of parts after the pull tab has been lifted further than as illustrated in FIG. 4;

FIG. 6 is a fragmentary horizontal sectional view on an enlarged scale, of a portion of the end closure of FIG. 1; the section being taken through the shank of the rivet with the pull tab omitted, and showing the configuration of the score lines in the area surrounding the rivet;

FIG. 7 is a view partly in section taken substantially along the line 7--7 of FIG. 6;

FIG. 8 is a view in section taken substantially along the line 88 of FIG. 6;

FIG. 9 is a view taken substantially along the line 9-9 of FIG. 6;

FIG. 10 is a view taken substantially along the line 1010 of FIG. 7; and

FIG. 11 is a view similar to FIG. 6, but showing a modified form of the invention.

Description of the preferred embodiments As a preferred and exemplary embodiment of the present invention, FIGS. 1 and 2 disclose a circular can end closure 20, preferably formed of a suitable metal such as aluminum or tin plate, formed with a circular central panel or wall 22 surrounded by a reenforcing groove 24 which merges into an upwardly extending countersink wall 26 which at its upper end merges into an outwardly extending edge-curled flange 28.

A removable section 30 is set off in the wall 22 by an endless, rupturable or principal score 32 of substantially uniform depth which is indented or impressed directly into the metal of the end by suitable scoring dies in the usual manner. At the outer end of the removable section 30, the score 32 is positioned just inwardly of the groove 24, and at the inner end a portion 33 of it extends in a partial circle around a portion of an upwardly extending hollow rivet 34 which is formed integral with the removable section 30 and is preferably disposed at the center of the end. The rivet 34 may be of any suitable type, one such type being disclosed in U.S. Patent 3,191,797.

The shank of the rivet 34 passes through a small circular hole, indicated by the numeral 36, which is formed in one end of an opening tab 40, the upper end of the rivet 34 being formed with an enlarged head 42 which overlies the metal of the tab 40 around the hole 36 to secure the tab to the can end.

The hole 36 is positioned at the bottom of a bell-shaped depression 44 which is disposed at one end of the tab 40 and is formed with a conical side wall 45 which extends upwardly away from the end panel 22 and terminates in an outer edge 46. It will be noted that the portion of the depression 44 immediately beneath the rivet head is somewhat flattened as an incident to the rivet heading operation. The opposite end of the tab 40 is formed into a ring-shaped pull handle 47. If desired, any other suitable shaped handle may be provided. Preferably, the peripheral outer edge of the tab 40 is hemmed or rolled downwardly and inwardly to form a hem 48 while the inner edge of the ring-shaped handle portion is similarly hemmed as at 50. The construction of the tab 40 is covered by U.S. Patent application S.N. 545,714 filed in the names of John Wilson Rouse and Harley Earl Simmons. It is to be understood that the particular tab 40 described herein is only a preferred embodiment and not an essential one and that other tabs, as for example the tab disclosed in U.S. Patent 3,191,797 could be used with the instant invention and function satisfactorily.

In use, the end closure 20 is secured to the upper end of a conventional cylindrical can body 60 in a conventional double seam 62 wherein the end flange 28 is interfolded with the upper edge of the body 60. (See FIGS. 3 and 5.) It will be understood that the bottom end of the body 60 is sealed (not shown) in any suitable manner and that a product (not shown) is contained in the sealed can. The upward bulge of the central panel 22 which is seen in FIGS. 3 and is usually present when the can has been filled with a beverage (not shown) such as beer or soda and sealed. In many instances, the beverage is either packed under pressure or generates its own pressure. In either event, the pressure inside the can bulges its ends upwardly. With non-pressurizing products, of course, the end would retain the flat shape shown in FIG. 2.

When the can is to be opened, the user grasps the outer edge of the ring handle 47 and pulls upwardly on it, thus causing the handle to rock upwardly as clearly seen in FIG. 4. The lifting of the handle subjects the rivet 34 and the surrounding metal to a sharp upward twisting or rocking action which exerts great stress on the inner circular portion 33 of the score 32 (see FIG.

6) which closely surrounds the rivet 34, thus causing the thinned and weakened metal at the bottom of this portion 33 of the principal score 32 to rupture, the initial rupture occurring at about the area of the score portion 33 which is indicated by the letter R, which area is disposed generally in close proximity to the center line of the opening tab 40.

In order to minimize the force required to thus initiate the rupture in the principal score, auxiliary scoring is provided. FIG. 6 shows one embodiment employing

auxiliary scores

64 and 66 which join with and extend at an angle to the principal score line portion 33. They preferably lie equidistant from and on either side of the center-line of the pull tab which overlies them. The

auxiliary scores

64 and 66 are of substantially the same depth as the principal score 32, as shown in FIGS. 7, 8 and 9.

A second embodiment of the instant invention is shown in FIG. 11. In this embodiment, only one auxiliary score line 68 is impressed into the can end. Preferably it is parallel to and underlies or is closely adjacent to the longitudinal oenterline of the lift tab 40. The score 68 is of the same depth as the score 32.

*In both embodiments, the auxiliary score lines extend from locations on the principal score portion 33 which are close to the area R at which the greatest stress is applied to the removable section upon lifting of the lift tab by the user, which area R in general lies along or adjacent to the center-line of the opening tab 40, and the auxiliary scores serve to reduce the force necessary to initiate the rupture of the principal score line in this area.

As has been pointed out supra, perhaps all of the reasons why the auxiliary scores function as they do are not completely understood. It is known, however, that a scoring operation creates stresses in the thinned wall portion at the bottom of the score. It is also known that it creates stresses in the metal laterally of the score, and it is believed that because of the proximity of the auxiliary scores to the portion 33 of the principal score 32, the stresses created during the formation of the auxiliary scores are superimposed, in the portion 33, upon the stresses which are normally present there. It is also believed that formation of the auxiliary scores creates additional work hardening of the metal in and around the area 33 of the principal score. Both of the above described eifects could account for the reduction in the pop value of the end embodying the instant invention. Other etfects produced by the auxiliary scores in all probability also contribute to this reduction in pop value. Whatever the reasons, whether the embodiment of the invention as shown in FIG. 6 or the embodiment shown in FIG. 11 is employed, the lifting force required to initiate the break in the rupture area R of the score portion 33 is substantially reduced and the auxiliary scoring itself does not rupture.

When the handle of the opening tab of a conventional end is lifted so as to fulcrum the tab about its opposite end portion to initiate rupture of the principal score, a sharp crease frequently forms in the removable section adjacent to the rivet. The degree of flexural strain at this crease is often high enough to cause a fracture so that only a small portion of the removable section can be removed. This problem is controlled by locating a reenforcing bead 70 in the vulnerable portion of the removable section 30 to prevent the formation of the sharp crease.

The bead 70 extends radially of the circular end closure 20 and preferably underlies the edge 46 of the tab 40 as shown in FIGS. 2 through 4. As seen in the dotted line position of FIG. 5, the bead 70 does not completely prevent bending of the metal in the area contacted by the tab edge 46, but it does restrict the bending to a shallow curvature of the metal and thus prevents the formation of an excessively sharp bend in the removable section 30 when the tab is rocked about its end edge 46 thereby preventing inadvertent fracture of that section during its removal. The provision of the bead 70 in an opening tab is covered in copending patent application S.N. 635,059.

After the tear has been initiated, the user need only insert his finger in the opening of the ring-handle 47 and continue to exert an upward lifting and pulling force on it to cause continued tearing of the score 32 as seen in solid lines in FIG. 5. After the score 32 has been completely torn and the removable section 30 completely separated from the can end the product can be poured or drank from the can.

It is to be understood that the foregoing description treats only several preferred embodiments of the present invention. For instance, in some end constructions, the dividing scores would be located on the opposite side of the portion 33 of the principal score, i.e., on the same side of principal score 32 as the point at which the opening tab 40 is secured to the removable section. To put it another way, in some end constructions, the auxiliary scores would be positioned in the removable section rather than in the section which remains attached to the can. Other embodiments within the scope of the invention are possible and that many additions and substitutions, deletions and modifications may be made in the present invention as disclosed herein without exceeding its scope as defined in the following claims.

I claim:

1. A container component comprising a panel, a removable section in said panel defined by a principal score, an opening tab secured to said removable section and operative upon manipulation to impress an opening force at a location on or proximate to said principal score to cause an initial rupture in said score, and an auxiliary score positioned close enough to said location to lessen the force which must be exerted on said opening tab to cause said initial rupture in said peripheral score.

2. The component defined in claim 1 wherein said tab is joined to said removable section by a rivet, said principal score lies in proximity to said rivet for a portion of its length and said auxiliary score extends outwardly from said principal score.

3. The component defined in claim 1 wherein said auxiliary score underlies the longitudinal axis of said lift tab.

4. The component defined in claim 1 further comprising a second auxiliary score, both of said auxiliary scores positioned close enough to said location to lessen the force necessary to manipulate said opening tab to cause said initial rupture in said principal score.

5. The component defined in claim 4 wherein said tab is secured to said removable section with a rivet, said principal score having a portion thereof lying in proximity to said rivet, said auxiliary scores joined to said principal score at said portion, each of said auxiliary scores extending from said principal score and away from said rivet and is disposed on opposite sides of the longitudinal axis of said tab.

6. The component defined in claim 4 wherein both of said auxiliary scores are joined to said principal score.

7. A container component comprising a panel, a rupturable score in said panel, an opening tab secured to said panel and operative upon manipulation to impress a force at a location adjacent to said rupturable score to cause an initial rupture in said score, and an auxiliary score positioned close enough to said location to lessen the force which must be exerted at said location to cause said initial rupture in said rupturable score.

8. The container component defined in claim 7 wherein said opening tab is secured to said panel by a rivet and said rupturable score includes a portion thereof which closely encircles said rivet for a portion of the circumference of said rivet, and said auxiliary score line extends outwardly from said portion.

9. The container component defined in claim 8 wherein a second auxiliary score extends outwardly from said portion.

References Cited UNITED STATES PATENTS 3,283,946 11/1196 Stec 220-54 3,315,837 4/1967 Boik et al 22054 GEORGE T. HALL, Primary Examiner.