US3643832A

US3643832A - Pull tab arrangement for easy-opening container

Info

Publication number: US3643832A
Application number: US61529A
Authority: US
Inventors: Nick S Khoury
Original assignee: Continental Can Co Inc
Current assignee: Continental Can Co Inc
Priority date: 1970-08-06
Filing date: 1970-08-06
Publication date: 1972-02-22
Anticipated expiration: 1989-02-22
Also published as: CA951655A

Abstract

An easy opening container having a pull tab including a ring portion and pair of fulcrum legs straddling the weakening line defining a removable panel portion. The pull tab includes an attachment panel hingedly connected to the ring portion and between the fulcrum legs. The attachment portion receives a rivet formed integral with the removal panel portion. Cooperating means are formed on the pull tab and the panel for minimizing the stresses on the integral rivet. Wells disposed below the ends of the fulcrum legs reduce the force required to tilt the pull tab to a position in which the legs are the ends of a fulcrum lever.

Description

[ 1 Feb. 22, 1972 [54] PULL TAB ARRANGEMENT FOR EASY- OPENING CONTAINER [72] inventor: Nick S. Khoury, Worth, Ill.

[73] Assignee: Continental Can Company, Inc., New

York, NY.

22] Filed: Aug. 6, 1970 211 Appl.No.: 61,529

3,450,301 6/l969 Stec et al. ..220/54 Primary Exar ninerGeorge T. Hall AttorneyFred P. Kostka, Joseph E. Kerwin and William A. Dittmann ABSTRACT An easy opening container having a pull tab including a ring portion and pair of fulcrum legs straddling the weakening line defining a removable panel portion. The pull tab includes an attachment panel hingedly connected to the ring portion and between the fulcrum legs. The attachment portion receives a rivet formed integral with the removal panel portion. Cooperating means are formed on the pull tab and the panel for minimizing the stresses on the integral rivet. Wells disposed below the ends of the fulcrum legs reduce the force required to tilt the pull tab to a position in which the legs are the ends of a fulcrum lever.

4 Claims, 3 Drawing Figures PATENIEIIFEB 22 I972 3.643 8 3 2 INVENTOR NICK S. KHOURY BYJM PULL TAB ARRANGEMENT FOR EASY-OPENING CONTAINER BACKGROUND OF THE INVENTION The present invention relates to easy-opening containers and more particularly to a new and improved pull tab arrangement for opening the container.

The pull tab arrangement of the present invention is used in easy opening containers having a tear portion defined by a weakening line formed in a container panel. The tear portion is removed by a pull tab which is attached to the tear portion by a rivet formed integral with the tear portion.

The typical pull tab and rivet construction of the type to which the present invention relates is shown in US. Pat. No. 3,349,949. As shown, the pull tab terminates at one end in a pair of fulcrum legs which staddle the tear portion. Integral and rigid with the legs is a lifting portion in form ofa ring. The pull tab is connected to the tear portion by arivet integral with the latter. The rivet extends through an opening in an attachment panel extending from the ring portion between the two fulcrum legs of the pull tab.

In the prior structure the pull tab was supported on the panel in a manner such that the tab was subject to slight rocking movement. Such rocking movement may be caused by the stacking of cans or items thereon. The rocking movement is undesirable for the reason that this causes a stress on the rivet. Under some conditions the stress may be such that the rivet fails.

In order to minimize such rivet failure caused by rocking of the pull tab, it has been common practice to contour the fulcrum legs to lie in close proximity to the panel surface. This causes a problem in tilting of the tab to initiate the severance because the legs in contact with the panel resist the tilting. To facilitate the grasping of the pull tab, the pull tab is slightly raised above the panel along the rear portion of the ring. However, such modification does not reduce the force required to tilt the pull tab to the position at which theseverance of the tear portion occurs.

SUMMARY OF THE INVENTION By the present invention, it is proposed to provide an improved pull tab arrangement wherein the stresses on the rivet connection are reduced and the pull tab may be fully tilted to a position of at least 60 without encountering substantial resistance.

The foregoing is accomplished by an arrangement wherein the pull tab is supported along the major portion of its length by at least two spaced projections in a manner substantially eliminating any rocking movement. Elimination of the rocking movement minimizes the stresses imposed on the rivet and thereby renders the latter more resistant to abuse.

To reduce the force required to tilt the pulltab to a position for opening the container the portions of the panel underlying the fulcrum legs are indented so that the legs are out of contact with the panel surface until the pull tab is inclined to a predetermined angle. Thereafter, further inclination of the tab causes the legs to engage the panel surface so that the pull tab functions as a lever to apply an upward force on the rivet and thereby sever the tear portion from the panel along the weakening line.

Further features of the invention will hereinafter appear.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a top plan view of an easy opening container embodying the improved pull tab arrangement of the present invention.

FIG. 2 is a cross-sectional view taken generally'along the lines 2-2 of FIG. 1.

FIG. 3 is a fragmentary cross-sectional view of the container and the pull tab in an inclined position during the initial severance of the tear portion.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, there is shown an easy opening container 10 having a pull tab 11 mounted thereon in accordance with the present invention. The container 10 includes a cylindrical body 12 having an end closure (not shown) doubled seamed to the bottom end thereof. An easy opening end closure 13 is attached to the upper end of the container also by means of a double seam 14.

The easy opening end closure 13 includes a panel 15 in which there is provided a tear strip or removable panel portion 16. The removable panel portion 16 is defined by a weakening line 17 formed as by scoring or the like. The removable panel portion 16 may be of substantially tear drop contour having the narrow end thereof disposed on or adjacent to the center of the panel 15.

Formed integrally with the tear strip I6 is a rivet 18 which extends through a rivet accommodating opening 19 in an attachment panel 21. The rivet 18 is formed by initially drawing an enlarged bubble and thereafter reforming the bubble into a button. The pull tab attachment panel'21 is then placed on the button with the latter projecting through the opening 19. Thereafter, the button is staked to securely fasten the pull tab 11 on the panel 15. The staking operation creates stresses in the rivet which tend to reduce its abuse resistance. Under some circumstances the rivet structure may be weakened to the extent that it fractures causing the pull tab 11 to be separated therefrom prior to removal of the tear portion. These fractures may occur as a result of forces exerted on the pull tab 11 during opening and even prior to opening. The forces exerted on the rivet prior to opening of the container generally result from forces applied on the pull tab 11 by a container stacked thereon. These forces cause the pull tab to be rocked so that the attachment panel 21 is displaced. The displacementof the attachment panel 21 is such that it further imposes stresses on the rivet 19. In accordance with the present invention, the pull tab is mounted on the end closure in a manner such that stresses imposed on the rivet by way of the pull tab prior to opening the container are minimized.

As shown, the pull tab 11 is made from sheet metal and includes a finger grip portion 22 in the form ofa ring. The inner and outer peripheries of the ring 22 are formed with hemmed edges which serve to rigidify the pull tab 11 and also provide a smooth surface. The ring 22 is formed with angularly spaced and generally upright U-shaped projections 23. The projections 23 define a rear gripping area which is gripped between the thumb and forefinger to lift the pull tab 11.

At the forward or leading end, the pull tab 11 is provided with a pair of fulcrum legs 2424. The fulcrum legs extend substantially tangentially from the ring 22 and are hemmed along outer edges thereof. The inner edges of the legs 24 each are tapered or inclined downwardly and merge with a transition web 20 inclined downwardly from the forward edge of ring 22. Extending integrally from the transition web 20 for hinging movement is the attachment panel 21. A downwardly extending flange bounds the rivet opening 19 and reinforces the latter.

To maintain the rear end of the pull tab in close proximity to the upper surface of the panel 15, the panel 15 is formed with a pair of indentations 25 which receive the lower ends of the projections 23 therein. To further assist in maintaining a lengthwise support beneath the pull tab 11, a pair of upstanding beads 26 are formed in the panel 15. The beads are located and arranged to cooperate with the projections 23 seated in the indentations 25 and maintain the ring pull 11 against rocking. In this connection, it is to be noted that the beads 26 are in substantial linear alignment with the transitionweb 20 connecting the attachment panel 21 to the ring 22. This location of the beads 26 minimizes the rocking tendency of ring pull about the transitional web 20 so that minimum movement is transmitted thereto. Thus, the attachment panel normally remains stationary about the rivet so that lifting forcesresulting in stresses on the rivet are minimized until the pull tab 11 is tilted for opening or separating the tear strip 16 from the panel 15.

To facilitate the removal of the tear strip 16, the panel is formed with a pair of wells 2727 which underlie the fulcrum legs 24-24 of the pull tab 11. As shown, when the pull tab 1 l is disposed in the nonopening position, the ends of the fulcrum legs 2424 are spaced from the surface of the wells 2727. In this connection, it is to be noted that even though the ends of the legs 24-24 are unsupported, the pull tab 11 remains substantially stationary on the panel until a lifting force is applied at the ring 22. The stationary condition is maintained because of the support provided at the projections 23 and the beads 26.

Upon lifting to initiate severance or separation of the tear strip 16, the free ends of the fulcrum legs 24-24 are out of contact with the surfaces of the wells 2727. Thus, only the slight force necessary to bend the pull tab about the transition web is required to tilt the pull tab 11. However, when the legs 2424 strike or abut the upwardly inclined surfaces 28 of the wells 27-27, the fulcrum legs are operative to serve as the ends of a second class lever so that an upward lifting force is applied on the rivet 18. This causes the rivet 18 to be lifted whereby the score line 17 immediately adjacent thereto is severed. After initial severance a pulling force may be applied to the pull tab 11 to complete the separation of the tear strip 16 from the panel 15.

What is claimed is:

1. An easy opening container comprising an end panel having a tear portion defined by a score line, a pull tab having a ring portion and a pair of spaced fulcrum legs, said legs and said ring portion being rigidly connected so as to provide a rigid lever, an attachment panel connected to said ring portion and disposed between said fulcrum legs, said ring portion having a pair of spaced projections for supporting said ring portion on said panel, and beads projecting from said panel engaging the underside of said panel cooperating with said projections on said ring portion for providing lengthwise support of said pull tab.

2. The invention as defined in claim 1 wherein said panel includes a pair of indentations aligned with respective ones of said projections for accommodating said projections therein.

3. The invention as defined in claim 1 wherein said spaced projections are located substantially in line with the line along which the pull tab hinges relative to said attachment panel.

4. The invention as defined in claim 3 wherein wells are formed in said panel in alignment with the ends of said fulcrum legs, the surfaces of said wells being arranged for engagement with said ends when said ring pull end has been tilted sufficiently to permit free access of said fingers into the finger opening in said ring portion.