US3667643A - Easy-lift pull tab - Google Patents

Abstract

A pull tab for an easy opening container. The pull tab is of the type having a pair of fulcrum legs. The fulcrum legs are each formed with an extension of single layer of sheet metal which projects outwardly of the fulcrum ends of the legs.

Description

United States Patent Patel June 6, 1972 EASY-LIFT PULL TAB [56] References Cited [72] Inventor: Anilkumar J. Patel, Chicago, Ill. UNITED STATES PATENTS 3,437,229 4/1969 Khoury... ....220/54 [73] Assgnee' Cmmemal New 3,432,067 3/1969 Khoury ..220/54 York, NY.

[22] Filed; 28, 1970 Primary ExaminerGeorge T. Hall AttorneyFred P. Kostka, Joseph E. Kerwin and William A. [21] Appl. No.: 101,694 Dittmann [57] ABSTRACT [52] U.S. Cl ..220/54 [51] 17/20 A pull tab for an easy opening container. The pull tab is of the [58] Field of Search 220/54 48 27, 215/46 A type having a pair of fulcrum legs. The fulcrum legs are each formed with an extension of single layer of sheet metal which projects outwardly of the fulcrum ends of the legs.

3 Claims, 5 Drawing Figures PATENTEDJUN 5 I972 RL m MA P ATT'Y EASY-LIFT PULL TAB BACKGROUND OF THE INVENTION The present invention relates to easy opening containers and more particularly to a new and improved pull tab for effecting the separation of the tear portion from the container.

Pull tabs of the type shown in U.S. Pat. No. 3,349,949 are purposely designed to be rigid in order to function as levers during the opening. As a result, it is generally quite difficult to lift the tab to effect the rupture of the tear portion. These pull tabs are formed with fulcrum legs which straddle the score line at the end of the tear strip.

Efforts have been made to improve the lift characteristics as for example by either shortening the legs so that the ends of the fulcrum legs pivot on the inboard side of the centerline of the rivet. However, the fulcrum ends of the short legs do not always engage the upper surface of the end closure until the pull tab is tilted in overlying relationship with the end of the tear strip. Under these conditions the force exerted by the pull tab may be inadequate to separate the tear strip from the panel or the pull tab may separate from the tear strip. The short leg pull tab structure is exemplified by U.S. Pat. No. 3,303,959.

Further efforts to improve the lift characteristics of a pull tab are shown and described in US. Pat. No. 3,437,229. This patent discloses a pull tab in which the ring section is formed with a weakened section. The ring portion bends about the weakened section upon initial lifting so that easier gripping access is had to the pull tab. However, when the ring pull is thus bent the length of the moment applying arm of the second class lever formed by pull tab is effectively shortened whereby a reduced force is applied on the score line.

This requires that a greater force be exerted at the ring section. Thus, while the initial lifting of the pull tab from the end panel is made easier, the separation of the tear strip therefrom is made more difficult.

SUMMARY OF THE INVENTION By the present invention, it is proposed to provide a pull tab structure which overcomes the difiiculties encountered heretofore.

This is accomplished by providing a pull tab which is of onepiece construction and which may be economically formed from sheet metal in the same manner as pull tabs are currently being formed. The pull tab is formed with a ring portion and tangentially extending legs along the opposite sides of the rivet. The legs are adapted to straddle the tear portion adjacent a rivet connection. The legs portions are formed with extensions of single sheet thickness which extend beyond rigid folded end portions of the legs. The folded end portions in fulcrums ends disposed between the centerline of the rivet connection and the end of the score line defining the tear strip. Thus, upon tilting of the pull tab, the terminal ends of the folded pull tabs engage the single thickness extension. The single thickness then slides along the panel until the tab is tilted at angle wherein the ends apply a force on the score line. Because the ratio of the moment arm and the lever applying arm is increased a greater force is applied at the score line thereby to facilitate the opening at the tear strip.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary perspective view of an easy opening container having a pull tab embodying the structure of the present invention;

FIG. 2 is a top plan view ofthe container shown in FIG. 1;

FIG. 3 is a cross sectional view taken generally along the lines 33 of FIG. 2 and showing the pull tab in the normal non-use position on the panel;

FIG. 4 is a fragmentary underside view of the pull tab taken generally along the lines 44 of FIG. 3.

FIG. 5 is an enlarged fragmentary view similar to FIG. 3 but showing the pull tab in an inclined position for separation of the tear strip from the end panel,

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, there is shown an easy opening container 10 having a pull tab 11 embodying the structure of the present invention. The container 10 includes an end closure 12 which is secured to a body 13 as be means of a double seam 14. The end closure 12 includes a panel 16 having a tear strip or portion 17 defined by a score line 18. The pull tab 1 1 is secured to the tear portion by a rivet 19 formed integral with the tear strip.

The pull tab is intended to function as a lever to exert a sufficient upwardly directed force through the rivet 19 on one end of the tear strip 17 to effect an initial rupture of the end panel along that part of the score line 18 which extends about the starting end 21 thereof. In this connection, it is to be noted that the starting end 21 of the tear strip 17 is located in close proximity to the rivet 19.

The pull tab 1 1 is of a generally horse shoe shaped configuration and terminates at one end in a pair of transversely spaced fulcrums legs 22. The other end of the pull tab 11 is in the form ofa ring portion 23 having a finger receiving opening 24.

The pull tab 11 also has an integral cross bar 26 which is connected to the horse shoe shaped portion thereof inter mediate the ring portion 23 and the fulcrum legs 22 and which forms a boundary of the ring portion 23. The cross bar 26 has projecting therefrom a connecting portion 27 which is generally strap-like and which is separated from the horse shoe shaped portion of the pull tab by a pair of longitudinally extending notches 28. The connecting portion 27 projects longitudinally beyond the fulcrums legs 22 and has formed therein an aperture which receives the rivet 18.

The pull tab 11 is reinforced by an outer reversely curled peripheral hem 29 and an inner reversely curled peripheral hem 31 which is continuous and surrounds the finger opening 31. The free edge of the hems 29 and 31 substantially abut one another around a major part of the ring portion whereby the ring portion 23 is defined by a tubular border part 32 as is best shown in FIG. 4. The tubular border part 32 may be considered to include an upper wall 33, the hem 31 and a connecting wall 34.

It is to be noted that the end of the pull tab 11 remote from the fulcrum legs 22-22 is disposed closely adjacent the double seam 14. Thus, it is difficult to grip to effect the lifting of the pull tab 11 which is required to tear out the tear strip 18. In order to facilitate the initial lifting of the pull tab 11, the ring portion is provided with a pair of radial beads 3636 which serve to elevate the rear section 37 of the ring portion 23 above the panel 16. While the pull tab 11 may be engaged because of this upward offsetting of the rear section 37 sufficient lifting force still cannot be applied by the fingers without difiiculty.

Accordingly, in accordance with the present invention, the forward of the fulcrum legs 22 are modified to facilitate the grasping and tilting of the pull tab. As shown, the upper panel 33 and the connecting portion 33 are cut-away along a line rearwardly or inboard of the centerline of the rivet 19. This, in effect shortens the fulcrum legs so as to provide fulcrum ends 39-39 which are disposed along a line extending between the center line of the rivet l9 and the inner most portion of the score line. Thus, the end portions of the underlying flange 29 define extensions 4141 which extend beyond the fulcrum ends 3939.

Due to the location of the fulcrum ends 39--39 of the fulcrum legs, it will be readily apparent from FIG. 5 that a lifting force exerted on the offset end 39 of the ring portion will effect the easy bending of extensions 39 at the terminal or fulcrum ends of the legs 22. The extension slide along the top or upper surface of the end closure panel 12 until the terminal or fulcrum ends 39 is in engagement with the extensions 41 to restrain further sliding movement. A further upwardly directed force applied to the ring portion 23 causes the pull tab 11 to function as a lever to effect the rupture of the tear portion along the score line 17.

What is claimed is:

1. In a pull tab of the lever type made from sheet metal and having a hemmed border to rigidify the same, said pull tab being secured to a container tear strip for effecting the removal thereof and wherein said pull tab at one end includes a pair of fulcrum leg and means for facilitating attachment to a container tear strip disposed between said legs and at the other end a ring portion to facilitate the lifting of said pull tab, the improvement comprising a single layer thickness of sheet metal projecting from said hemmed border to said fulcrum legs, and said hemmed border in each of said legs terminating 2. The invention as defined in claim 1 wherein said single layer thickness is a continuation of a hem of said hemmed border.

3. The invention as defined in claim 2 wherein said hem extension is disposed along the underside of said hemmed border.

Claims (3)

1. In a pull tab of the lever type made from sheet metal and having a hemmed border to rigidify the same, said pull tab being secured to a container tear strip for effecting the removal thereof and wherein said pull tab at one end includes a pair of fulcrum leg and means for facilitating attachment to a container tear strip disposed between said legs and at the other end a ring portion to facilitate the lifting of said pull tab, the improvement comprising a single layer thickness of sheet metal projecting from said hemmed border to said fulcrum legs, and said hemmed border in each of said legs terminating in fulcrum ends disposed between the center line of said rivet and the end of said score line.

2. The invention as defined in claim 1 wherein said single layer thickness is a continuation of a hem of said hemmed border.

3. The invention as defined in claim 2 wherein said hem extension is disposed along the underside of said hemmed border.

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