US3773210A

US3773210A - Opening tab for easy open container

Info

Publication number: US3773210A
Application number: US00257598A
Authority: US
Inventors: C Radtke
Original assignee: C Radtke
Current assignee: Rexam Beverage Can Co
Priority date: 1972-05-30
Filing date: 1972-05-30
Publication date: 1973-11-20
Anticipated expiration: 1990-11-20

Abstract

An opening tab for an easy open container having an attachment portion secured to a removable panel included in the central panel of an end closure, a fulcrum portion integrally connected to the attachment portion and having a fulcrum edge for fulcruming said opening tab against the central panel of the end closure spacially distant from the removable panel, and a lifting handle integrally connected to said fulcrum portion and forming a longitudinally rigid lever therewith. A reinforcing means is provided in the fulcrum portion extending into and interrupting the juncture between the fulcrum and attachment portions thereby preventing the formation of a sharp angle of bend at the juncture between the fulcrum and attachment portions during the fulcruming operation and also increasing the strength of the fulcrum portion during the fulcruming operation.

Description

United States Patent [1 1 Radtke NOV. 20, 1973 OPENING TAB FOR EASY OPEN CONTAINER [76] Inventor: Charles Stephan Radtke, 37 Beech St., Little Ferry, NJ. 07643 [22] Filed: May 30, 1972 [21] Appl. No.: 257,598

Primary Examiner-George T. Hall Attorney-Robert P. Auber et al.

[57 ABSTRACT An opening tab for an easy open container having an attachment portion secured to a removable panel included in the central panel of an end closure, a fulcrum portion integrally connected to the attachment portion and having a fulcrum edge for fulcruming said opening tab against the central panel of the end closure spacially distant from the removable panel, and a lifting handle integrally connected to said fulcrum portion and forming a longitudinally rigid lever therewith. A reinforcing means is provided in the fulcrum portion extending into and interrupting the juncture between the fulcrum and attachment portions thereby preventing the formation of a sharp angle of bend at the juncture between the fulcrum and attachment portions during the fulcruming operation and also increasing the strength of the fulcrum portion during the fulcruming operation.

10 Claims, 5 Drawing Figures OPENING TAB FOR EASY OPEN CONTAINER The present invention relates generally to easy open containers having removable panels defined by a score line included in the central panel of the end closure. More particularly, the present invention relates to an improved opening tab attached to the removable panel of such easy open containers.

One of the significant achievements in the container making industry in recent years has been the development of the easy open container which does not require the use of separate opening tools, such as can openers, etc. One type of easy open container which has been developed is provided with a removable panel in the central panel of the container end closure which is defined by a score line in the central panel. An opening tab is secured to the removable panel in order to facilitate detachment of the removable panel from the central panel by rupture of the score line. One category of such easy open containers utilizes the so-called reverse lift opening tab attached to the removable panel of the end closure. Examples of this opening tab can be found in U.S. Pat. No. 2,085,200, to Ljungstrom, granted June 29, 1937, US. Pat. No. 3,403,811, to Moller et al., granted Oct. 1, 1968, and US. Pat. No. 3,445,028, to Brown, granted May 20, 1969.

This reverse lift" opening tab typically includes an attachment portion, a fulcrum portion and a lifting handle. The attachment portion is ordinarily secured, as by a rivet, to a leading portion of the removable panel located substantially at the center of the central panel of the end closure. The fulcrum portion is integrally connected to the attachment portion and is fulcrumable on the central panel spacially distant from the leading portion of the removable panel to which the attachment portion of the tab is secured. The lifting handle, which may be in the form of a pull ring, is integrally connected to the fulcrum portion so that the combination forms a longitudinally rigid lever with the lifting handle overlying the removable panel of the central panel of the end closure. Movement of the lifting handle in a direction away from the central panel of the end closure causes the fulcrum portion of the opening tab to fulcrum on the central panel and, by means of the lever action of the lifting handle and the fulcrum portion, a lifting force is caused to be applied through the attachment portion of the opening tab to the rivet securing the attachment portion of the removable panel to thereby initiate rupture of the score at the leading portion of the removable panel adjacent to the rivet. I

In all such reverse lift opening tabs of the prior art a sharp line of bend results along the juncture between the attachment and fulcrum portions during the upward lifting movement of the lifting handle for initiating rupture of the leading portion of the removable panel. The reason that this bending occurs at the juncture between the fulcrum and attachment portions is that there is a concentration of stresses at this juncture resulting from the abrupt dimensional change between the fulcrum and attachments portions. When such prior art reverse lift" opening tabs are formed of a relatively soft and malleable material, such as aluminum, this sharp line of bend tends to rupture, due to exceeding the yield point of the material, thereby severing the attachment portion from the remainder of the opening tab prior to the complete detachment of the removable panel from the central panel of the end closure and possibly prior to the initial rupturing of the score. This inadvertent fracturing of the metal at the juncture between the attachment and fulcrum portions of the reverse lift" opening tab results in the users dismay as to how to complete the opening of the container which has not been or only partially been opened. In such a situation it is not uncommon for the user to evert to the use of other separate opening devices if available. One means of avoiding this result has been to produce such opening tabs from materials having sufficient strength, such as steel. However, the use of a hard material has disadvantages relating to the cost of production, for example the tooling required is expensive and wears out rapidly. Another means of increasng the strength of the tabs has been to increase the dimensions of the tabs which also undesirably increases the cost.

It is, therefore, an object of the present invention to provide an improved reverse lift opening tab for an easy open container wherein a sharp line of bend at the juncture between the attachment and fulcrum portions of the opening tab is prevented, thus substantially eliminating the possibility of fracture at the juncture during the opening operation.

The above object and others, which will hereinafter become apparent, are accomplished by providing an improved reverse lift" opening tab according to the present invention. The opening tab is constructed having an attachment portion secured to the leading portion of removable panel located substantially at the center of the central panel of an end closure, a fulcrum portion integrally connected to the attachment portion,

' a lifting handle integrally connected to the fulcrum portion so that a longitudinally rigid lever is formed therewith, and reinforcing means provided with the fulcrum portion and extending into the juncture between the fulcrum and attachment portions. The reinforcing meanseffectively prevents the formation of a sharp angle of bend at the juncture of the fulcrum and attachment portions of the opening tab and also increases the strength of the fulcrum portion during the fulcruming operation.

The present invention will be described and under stood more readily when considered together with the embodiment of the accompanying drawing, in which:

FIG. 1 is a partial plan view of a container end closure incorporating the reverse lift opening tab of the present invention;

FIG. 2 is a partial cross-sectional view of the container end closure of FIG. 1 taken along the line 2 2 of FIG. 1;

FIG. 3 is a partial cross-sectonal view of the container end closure of FIG. 1 similar to FIG. 2 in an initial stage of opening of the container;

FIG. 4 is a cross-sectonal view of the container end closure of FIG. 1 similar to FIG. 2 in a later stage of opening of the container; and

FIG. 5 is a cross-sectional view of the container end closure of FIG. 1 similar to FIG. 2 in yet a later stage of opening of the container. I

Now referring to the drawings, there is shown in FIG. 1 and 2 an end closure, generally designated 10, for an easy open container. End closure 10 may be circular and constructed of steel, aluminum, tin plate or other suitable rupturable 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 reinforcing groove 14, which in turn merges at its outer edge into upwardly extending wall 16, The upper end portion of wall 16 merges with outwardly extending curled flange 18 which, after assembly of end closure with a container body (not shown) becomes a portion of the container end seam (not shown).

Included in central panel 12 is removable panel, generally designated 20, which is defined by and included within score line 22. Removable panel 20 becomes detached from end closure 10 when score line 22 is completely ruptured thereby permitting the contents of the container to be dispensed from the opening produced by the removal of removable panel 20. Removable panel 20 may be formed in any desired pattern having a smaller leading portion, generally designated 24, located substantially in the center of the end closure and a larger portion, generally designated 26, extending closely adjacent the periphery of central panel 12.

In order to rupture score 22 and detach removable panel 20 from enclosure 10, an opening tab, generally designated 28, is provided. Opening tab 28 has an attachment portion 30 secured to the smaller leading portion 24 of removable panel 20 by means of rivet 32 which may be formed integrally with removable panel 20. Attachment portion 30 is connected to a fulcrum portion, generally designated 34, of opening tab 28 through vincular segment 36 at juncture 38. A lifting handle, designated 40, is provided integrally connected to fulcrum portion 34. Liftinghandle 40 may be in the form of a pull'ring adapted for receiving the finger of the user.

Attachment portion 30 of opening tab 28 substan-- tially radiates into the center of pull ring 40 and is provided with an opening 42 for receiving the shank 44 of rivet 34. As clearly seen in FIG. 2, attachment portion 30 lies in a plane below fulcrum portion 34 and, thus, vincular segment 36 which integrally connects attachment portion 30 to fulcrum portion 34 is inclined upwardly from attachment portion 30 to fulcrum portion 34.

Fulcrum portion 34 of opening tab 28 is spacially distantly removed from the leading portion 24 of removable panel 20 and is provided with a rounded, substantially straight line, fulcrum surface 46 for the purpose of reducing the friction between opening tab 28 and central panel 12 of the end closure 10 during the fulcruming operation, which is clearly illustrated in FIGS. 3 to 5. Reinforcing means preferably in the form of a raised bead, generally designated 48, is formed in fulcrum portion 34 of opening tab 30 for the purpose of maintaining the structural integrity of the opening tab during the fulcruming operation. Although shown in the drawing as being substantially in the shape of a W, bead 48 may be formed in any shape desired so long as a portion 50 of the bead extends into and interrupts the juncture 38 and also provided that bead 48 extends substantially across fulcrum portion 34. Bead 48 is formed having an arcuate shaped cross sectional profile as clearly seen in FIG. 2, however, other cross sectional configurations are suitable.

Lifting handle 40, which, as above indicated, may be in the shape of a pull ring suitable for the insertion of the users finger, overlies removable panel 20 and in cooperation with fulcrum portion 34 forms a longitudinally rigid lever having as its fulcrum point fulcrum surface 46.

Opening tab 28 may be formed from any suitable sheet metal material, such as steel, aluminum, etc., into the shape indicated in the drawings. However, with the provision of reinforcing means 48, it is possible and preferable to form the tab from a relatively soft and malleable material such as aluminum.

The operation of the reverse lift" opening tab according to the present invention is illustrated in FIGS. 3, 4 and S. In order to open a container provided with an opening tab according to the present invention the user begins by grasping the pull ring 40 with his finger and exerting an upward lifting force on the pull ring causing the pull ring to lift upwardly and away from central panel 12, as indicated by the arrow, thereby initiating the fulcruming operation as clearly seen in FIG. 3. During the fulcruming operation, resulting from the continued lifting movement of pull ring 40, the rounded, substantially straight line, fulcrum surface 46 of fulcrum portion 34 moves along central panel 12 in the direction indicated by the arrow. Simultaneously with this fulcruming movement of opening tab 28, the vincular segment 36, which interconnects attachment portion 30 to fulcrum portion 34, bends at juncture 38 thereby imparting an upward force on attachment portion 30 which force is transmitted to rivet 32 of removable portion 20. When this upward force on rivet 32 is sufficient, the popping of score 22 at the smaller portion 26 of removable portion 20 results, as clearly seen in FIG. 4. Continued movement of pull ring 40, as illustrated in FIGS. 4 and 5, together with the fulcruming action of the pull ring about fulcrum portion 34 results in the tearing of score line 22. Upon completion of the fulcruming operation, as when the pull ring 40 is substantially perpendicular to central panel 12, the user pulls the opening tab 28 away from end closure 10 thereby continuing the tearing of score line 22. When score line 22 is completely tom the removable portion 20 becomes detached from central panel 12. The provision of raised bead 48, included in fulcrum portion 34, having a portion 50 extending into vincular segment 36 and interrupting juncture 38 provides reinforcing for the fulcrum portion and the vincular segment during the fulcruming operation. Portion 50 of bead 48, which extends into vincular segement 36, reinforces the vincular segment perpendicularly to the bend which occurs during the fulcruming operation so that the strain in the segment is more evenly distributed and the yield point of the material is not exceeded. This even distribution of the strain in the vincular segment is the result of eliminating the sharp angle of bend. Thus, when relatively soft and malleable materials are utilized, such as aluminum, the prevention of a sharp angle of bend in the vincular segment insures against the rupturing of the vincular segment during the fulcruming operation. Additionally, the provision of the raised bead 48 extending across fulcrum portion 34 of opening tab 28 reinforces the fulcrum portion "to thereby prevent bending thereof during the fulcruming operation.

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 score of the following claims.

What is claimed is:

1. An opening tab for removing the removable panel from the wall of an easy open container, said removable panel having a leading portion located substantially in the center of said wall, said opening tab comprising:

an attachment portion secured to the leading portion of said removable panel;

a fulcrum portion integrally connected to said attachment portion at a juncture, said fulcrum portion having a fulcrum surface for bearing against the wall of said container spacially distant from the leading portion of said removable panel;

a lifting handle overlying said removable panel integrally connected to said fulcrum portion and forming a longitudinally rigid lever therewith extending from said fulcrum surface; and

reinforcing means formed in said fulcrum portion extending into and interrupting the juncture between said fulcrum and attachment portions thereby to prevent the formation of a sharp angle of bend at said juncture between said fulcrum and attachment portions during the fulcruming operation.

2. The opening tab as defined in claim 1 wherein the juncture between said fulcrum and attachment portions includes a vincular segment integrally interconnecting said fulcrum and attachment portions.

3. The opening tab as defined in claim 1 wherein said reinforcing means extends substantially across said fulcrum portion thereby to reinforce said fulcrum portion during the fulcruming operation.

4. The opening tab as defined in claim 1 wherein said reinforcing means comprises a raised bead formed in said fulcrum portion and having a portion extending into and interrupting the juncture between said fulcrum and attachment portions.

5. The opening tab as defined in claim 4 wherein said raised bead has an arcuate shaped cross sectional configuration.

6. The opening tab as defined in claim 1 wherein said attachment portion is disposed lower than said fulcrum portion.

7. The opening tab as defined in claim 1 wherein said opening tab is formed from a relatively soft and malleable metallic material.

8. The opening tab as defined in claim 7 wherein said relatively soft and malleable metallic material is aluminum.

9. The opening tab as defined in claim 1 wherein said lifting handle includes a pull ring.

10. An opening tab formed of aluminum for removing the removable panel from the wall of an easy open container, said removable panel having a leading portion located substantially in the center of said wall, said opening tab comprising:

a fulcrum portion having a fulcrum surface for bearing against the wall of said container spacially distant from the leading portion of said removable panel;

an attachment portion secured to the leading portion of said removable panel and disposed lower than said fulcrum portion;

a vincular segment integrally interconnecting said attachment and fulcrum portions at a juncture therebetween and sloping downwardly from said fulcrum portion to said attachment portion;

a pull ring overlying said removable panel integrally connected to said fulcrum portion and forming a longitudinally rigid lever therewith extending from said fulcrum surface; and

reinforcing means in the form of a raised bead formed in and substantially across said fulcrum portion, said raised bead having a portion extending into said vincular segment at the juncture between said attachment and fulcrum portions thereby to reinforce said fulcrum portions and to prevent the formation of a sharp angle of bend in said vincular segment during the fulcruming operation.

Claims

1. An opening tab for removing the removable panel from the wall of an easy open container, said removable panel having a leading portion located substantially in the center of said wall, said opening tab comprising: an attachment portion secured to the leading portion of said removable panel; a fulcrum portion integrally connected to said attachment portion at a juncture, said fulcrum portion having a fulcrum surface for bearing against the wall of said container spacially distant from the leading portion of said removable panel; a lifting handle overlying said removable panel integrally connected to said fulcrum portion and forming a longitudinally rigid lever therewith extending from said fulcrum surface; and reinforcing means formed in said fulcrum portion extending into and interrupting the juncture between said fulcrum and attachment portions thereby to prevent the formation of a sharp angle of bend at said juncture betwEen said fulcrum and attachment portions during the fulcruming operation.

10. An opening tab formed of aluminum for removing the removable panel from the wall of an easy open container, said removable panel having a leading portion located substantially in the center of said wall, said opening tab comprising: a fulcrum portion having a fulcrum surface for bearing against the wall of said container spacially distant from the leading portion of said removable panel; an attachment portion secured to the leading portion of said removable panel and disposed lower than said fulcrum portion; a vincular segment integrally interconnecting said attachment and fulcrum portions at a juncture therebetween and sloping downwardly from said fulcrum portion to said attachment portion; a pull ring overlying said removable panel integrally connected to said fulcrum portion and forming a longitudinally rigid lever therewith extending from said fulcrum surface; and reinforcing means in the form of a raised bead formed in and substantially across said fulcrum portion, said raised bead having a portion extending into said vincular segment at the juncture between said attachment and fulcrum portions thereby to reinforce said fulcrum portions and to prevent the formation of a sharp angle of bend in said vincular segment during the fulcruming operation.