US3591038A

US3591038A - Easy-open end with abuse-resistant opening tab

Info

Publication number: US3591038A
Application number: US857396A
Authority: US
Inventors: Alexander Walker Mooring; Harley Earl Simmons
Original assignee: American Can Co
Current assignee: Rexam Beverage Can Co
Priority date: 1969-09-12
Filing date: 1969-09-12
Publication date: 1971-07-06
Anticipated expiration: 1988-07-06
Also published as: GB1329467A; CA926323A

Abstract

A scored can end closure is provided with an opening tab which is secured adjacent the score to a panel of the closure by a rivet and is held against vibration during shipment to prevent inadvertent rupture of the score. The opening tab is formed with downwardly curled edges, at least one portion of which is opened up, or made greater in diameter than the adjacent portions, so that it extends downwardly and contacts the end at an area spaced from the rivet, even when the panel is bulged outwardly by internal pressure, and thus dampens the tab against vibration during long distance shipment in freight cars and trucks.

Description

United States Patent EASY-OPEN END WITH ABUSE-RESISTANT OPENING TAB 3 Claims, 6 Drawing Figs.

U.S. CL... 220/54 Int. Cl 865d 17/24 Field of Search 220/54, 27; 215/46 [56] References Cited UNITED STATES PATENTS 3,404,801 l0/l968 Silver r 220/54 3,432,067 3/1969 Khovry 220/54 Primary ExaminerGeorge T. Hall Atrorneys- Robert P. Auber, George P. Ziehmer and Leonard R. Kohan ABSTRACT: A scored can end closure is provided with an opening tab which is secured adjacent the score to a panel of the closure by a rivet and is held against vibration during shipment to prevent inadvertent rupture of the score. The opening tab is formed with downwardly curled edges, at least one portion of which is opened up, or made greater in diameter than the adjacent portions, so that it extends downwardly and contacts the end at an area spaced from the rivet, even when the panel is bulged outwardly by internal pressure, and thus dampens the tab against vibration during long distance shipment in freight cars and trucks.

EASY-OPEN END WITI-I ABUSE-RESISTANT OPENING TAB.

BACKGROUND OF THE INVENTION One of the more widely used types of easy-open containers is a metal can which has formed in its top end a tear-out removable section which is defined by a score line and which has a pull-type opening tab riveted at one end to that section to expedite its removal. The opening tab is manipulated by the consumer to first rupture the score and to then tear the score to detach the removable section from the end to give access to the product. In order to minimize the force which must be applied on the pull tab to initiate rupture in the score line, a portion ofthe score is disposed closely adjacent to the rivet.

On the problems which has heretofore existed with this type of container is that during prolonged shipment or other rough handling the opening tab, which contacts the end panel only at its riveted end, vibrates in a springboard effect and transmits its vibrations to the rivet to stress and eventually fracture the portion of the score close to it due to metal fatigue which occurs in the thin metal of the score. Such premature fracture of the score has been particularly severe during long-distance shipment, where the tab vibrations in many instances are almost continuously present.

SUMMARY OF THE INVENTION The present invention overcomes the problem of premature score fracture which is discussed above by preventing the opening tab which is riveted to the scored removable area in a can from vibrating sufficiently during shipment of the container to induce premature rupture of the score line. This is accomplished by providing means for maintaining continuous contact between the free handle of the tab and the end, at areas spaced from the rivet, in order to dampen or prevent vibration of the tab. This is done by increasing the diameter of the curled edges of the tab in areas closely spaced from the rivet edges of the tab in areas closely spaced from the rivet so that the curled edges in those areas project below the normal contour of the tab and fill the gap which normally exists between the tab and the end panel.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan view of an end closure made in accordance with the present invention and prior to its application to the can body;

FIG. 2 is a vertical sectional view, on an enlarged scale, taken substantially along the line 2-2 of FIG. 1;

FIG. 3 is a vertical sectional view corresponding to FIG. 2, but taken through the end after it has been seamed onto a filled can and bulged outwardly by the pressure of the cans contents; and

FIGS. 4, 5 and 6 are section details on an enlarged scale, taken substantially along the lines 44, 5-5, and 6-6, respectively of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The drawings disclose a metal can end closure indicated generally as 10 having a gently rounded central panel 12 and a compound-lined, curled peripheral flange 14. The panel 12, which if desired could be flat, includes a removable section 16, defined by an endless score line 18, which when removed provides a dispensing opening. Within the removable section 16 is a rivet 20 which is centrally located on the end and secures an opening tab 22 in place on the closure.

As shown in FIG. 2 the rivet 20 includes a generally cylindrical shank 23 and a horizontal transverse wall 24 at the upper end of the shank 23. The transverse wall 24 extends outwardly to an annular bead 26 which projects over a portion of the pull tab 22 and clamps it to the panel 12. The rivet 20 extends through a hole 27 which is formed at the bottom of a depression 28 which is formed at the fulcrum end 29 ofthe tab 22. The opposite, handle end 30 of the tab 22 is formed into a pull ring 32, the inner edge of which is defined by a downwardly extending edge curl 34 of small cross-sectional diameter. The major portion of the outer edge of the pull ring 32 is defined by a similar edge curl 36 which is formed with a pair of side extensions 38 which extend along the sides of the tab and terminate at points 39 adjacent the fulcrum end 29 of the tab. It will be noted that the bottom portions of the

edge curls

34, 36 comprise the lowermost surfaces of the handle portion 30 of the tab 22 and are, in common with the other portions of the handle end 30, spaced slightly above the panel 12.

In order to minimize the force which must be applied by fulcrum end 29 of the opening tab 22 to initiate rupture in the score 18 when the pull ring 32 is lifted, a section 40 of the score 18 is located closely adjacent to and in encircling relationship to a portion of the rivet shank 23.

This placement of the score section 40 renders it very vulnerable to vibrations of the tab 22, since the vibrations of the tab 22 are transmitted to the rivet 20 and thence into the score section 40. If the stresses caused by these vibrations are applied to the score section 40 over a long period of time, the thinned metal in the section 40 becomes fatigued and eventually cracks. In order to prevent premature rupture of the score section 40 means are provided to prevent vibrations of the tab 22, or to at least so minimize them so that they will not fatigue the metal in the score section 40.

This is effected by opening up," e.g., expanding or increasing the diameter of, a portion 42 of the edge curl 34 in such manner that its bottom edge portion projects below the bottom contour of the adjacent portions of the edge curl 34 and actually contacts the end panel 12 and thus fills the gap 44 which exists between the handle end 30 and the panel 12. Preferably, the portion 42 projects downwardly a sufficient distance to tilt the opening tab 22 upwardly in order to maintain it under tension, even when the end 10 is not attached to a can and the panel 12 is not bulged upwardly under pressure of the contents. However, the upward force exerted on the tab 22 by the expanded curl section 42 must not be great enough to rupture the score section 40.

In order to steady the tab 22 against lateral rocking, the terminal edge portions 54 of the edge curl 36 may be bent downwardly into contact with the panel 12 in such manner as to also exert a slight tension against the panel 12 on either side of the rivet 20.

When the end 10 is applied to a can body 50, which is filled with a pressure-producing product P such as beer or carbonated soda, and its flange 14 is seamed onto the upper end of the body in a double seam 52, the pressure of the product P causes the end panel 12 to bulge upwardly and assume a more rounded form, as seen in FIG. 3. However, this change in shape is minimal in the area of the panel 12 which is contacted by the opened up" curl portion 42 and the curl portions 54, and is not sufficient to create a gap between the

curl portions

42, 54 and the panel 12, since even in the bulged position of the panel 12, the

portions

42, 54 maintain contact with the panel 12, and in fact preferably still maintain a slight pressure on it to maintain the tab 12 under tension and positively prevent it from vibrating during shipment and handling.

It should be appreciated that the

curl portions

42, 54 need not actually exert tension against, or even actually contact, the panel 12 in the bulged end condition of FIG. 3, since, if they only make light contact with, or are merely in closely spaced relationship to the panel 12, they will still function to dampen the vibrations of the opening tab 22 and thereby decrease the metal-fatiguing efiect. However, it is preferred that some tension be applied by these elements, since in such event their vibration-dampening effect is most effective.

It will also be understood that the curl portion 42 may be opened up" in ways other than by increasing its diameter. Thus, as an example, the metal in this portion may be extended downwardly vertically, or at an angle, in order to have it project below the adjacent portions of the curl 34 and to thereby contact the panel 12 and fill up the gap 44.

it is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

We claim: l. A can end closure having a panel, a score formed in said panel and defining a removable portion therein, and an opening tab, one end of said opening tab being secured to said panel adjacent said score by a rivet and the other end of said opening tab-comprising a handle end which is spaced above said panel, portions of said handle end being curled downwardly to form an edge curl, at least one area of which is opened up so that it projects downwardly beyond the adjacent portions of the edge curl a sufficient distance to contact the panel and thereby dampen the vibrations of said opening tab relative to said panel and prevent fracture of said score when the can end is subjected to abuse.

. 2. The can end closure of claim 1 wherein said handle end comprises a pull ring having its inner edge defined by said edge curl, and wherein the portion of said edge curl which is nearest said rivet is opened up.

3. The can end closure of claim 2, wherein the outer edge of said handle end is formed into a downwardly projecting edge curl which extends on adjacent opposite sides of said rivet, and wherein the terminal edge portions of said edge curl are bent downwardly into contact with said end panel to prevent lateral rocking of said tab.

Claims

1. A can end closure having a panel, a score formed in said panel and defining a removable portion therein, and an opening tab, one end of said opening tab being secured to said panel adjacent said score by a rivet and the other end of said opening tab comprising a handle end which is spaced above said panel, portions of said handle end being curled downwardly to form an edge curl, at least one area of which is opened up so that it projects downwardly beyond the adjacent portions of the edge curl a sufficient distance to contact the panel and thereby dampen the vibrations of said opening tab relative to said panel and prevent fracture of said score when the can end is subjected to abuse.

2. The can end closure of claim 1 wherein said handle end comprises a pull ring having its inner edge defined by said edge curl, and wherein the portion of said edge curl which is nearest said rivet is opened up.