Lever Action Tab System for Easy Opening Ends

This invention relates in general to new and useful improvements in easy opening container ends, and more particularly to an easy opening container end having a lever action tab system.

This invention particularly relates to container ends having removable panel portions wherein an associated pull tab is attached to the removable panel portion and upon initial actuation, the container end is ruptured and a portion of the removable panel portion is depressed inwardly into the container followed by the tearing out of the removable panel portion utilizing the pull tab as a handle. In accordance with this invention, a simple weakening line is provided immediately adjacent the connection between the pull tab and the removable panel portion with the weakening line providing three beneficial functions which are highly desirable. First, the container end is so constructed whereby when the pull tab is initially lifted to effect the opening of the container end, rupture of the end panel thereof occurs along the weakening line and venting of the interior of the container is permitted. This venting is desirable whenever the interior of the container is at a pressure other than atmosphere, either positive or negative. Second, after the initial venting occurs, further upward movement of the pull tab will result in further rupture of the end panel along the weakening line with the result that that portion of the end panel which is secured to the pull tab will hinge relative to the remainder of the end panel and function as a hinge for the pull tab. This eliminates the necessity of providing a hinge on the pull tab. Third, the newly formed hinge of the end panel functions to permit the nose of the pull tab to move radially outwardly and therefore the nose of the pull tab may be initially radially inwardly offset relative to the usual score line which defines the removable panel portion. As a result, the starting portion of the score line may be conveniently placed adjacent the chuck wall of the container end while sufficient clearance is provided between the chuck wall and the nose of the pull tab for the operation of the usual seaming chuck.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawing:

In the drawing

FIG. 1 is a plan view of a container having an easy opening end formed in accordance with this invention.

FIG. 2 is an enlarged fragmentary vertical sectional view taken along the line 2--2 of FIG. 1 and shows specifically the details of the container end and the tab system thereof.

FIG. 3 is a fragmentary horizontal sectional view taken along the line 3--3 of FIG. 2 and shows specifically the details of the weakening line formed in the end panel in accordance with this invention.

FIG. 4 is a fragmentary vertical sectional view similar to FIG. 2 and shows the initial rupture of the end panel along the weakening line of FIG. 3 upon the initial lifting of the pull tab.

FIG. 5 is another fragmentary vertical sectional view similar to FIG. 2 and shows the further action of the tab system in the opening of the container.

FIG. 6 is a fragmentary horizontal sectional view similar to FIG. 3 and shows a modified weakening line arrangement.

Referring now to the drawings in detail, it will be seen that there is illustrated a container which is formed in accordance with this invention, the container being generally referred to by the numeral 10. The container 10 may be of any type of construction, but is illustrated as including a can body 11, which may have one end (not shown) closed in any conventional manner, and the opposite end closed by means of an easy opening end, which is generally referred to by the numeral 12. The end 12, except for the easy opening features thereof is of a conventional construction and includes an end panel 13 which is generally defined by an upstanding chuck wall 14, the chuck wall 14 being a portion of a conventional double seam 15 which secures the container end 12 to the can body 11.

In the preferred embodiment of the invention, substantially the entire end panel 13 is removed in the opening of the container 10. To this end, the end panel 13 is provided with a peripheral score line 16 which is positioned as close as feasible to the chuck wall 14. At this time, it is pointed out that the removable panel configuration may be varied as required for the dispensing of the product packaged within the container 10 and the removable panel portion will not necessarily have a circular outline as is shown in FIG. 1. The configuration of the score line 16 will vary accordingly. However, the invention is particularly adapted to easy opening ends wherein starting portions of the score line are disposed closely adjacent the chuck wall 14.

In order to facilitate the rupture of the end panel 13 along the score line 16 and thereafter pull out the removable panel portion 17 defined by the score line 16, the end panel 13 is provided with an integral rivet 18 which is utilized in securing a pull tab, generally referred to by the numeral 20, to the end panel 13. The illustrated pull tab 20 is in the form of a lever and includes a rigid body 21 having at the forward end thereof a nose 22. At the opposite end of the rigid body there is a pull ring 23. The rivet 18 passes through the rigid body 21 and rigidly secures the pull tab 20 to the end panel 13.

It is to be understood that the configuration of the pull tab 20 may vary in accordance with the requirements thereof although the specific pull tab configuration illustrated in FIG. 1 is preferred.

In accordance with this invention, although it is necessary for the nose 22 to be positioned generally in alignment with the starting portion of the score line 16, the initial position of the nose 22 is radially inwardly of the score line 16, as is clearly shown in FIGS. 1 and 2. This permits sufficient clearance for a chuck (not shown) which engages the chuck wall 14 during a seaming operation required for the formation of the double seam 15. The radial inward offsetting of the nose 22 is permissible in accordance with this invention for reasons which will be defined hereinafter.

Referring now to FIGS. 2 and 3 in particular, it will be seen that the end panel 13 is provided with a further score line 24 which is preferably formed in the underside of the end panel. The score line 24 includes a central portion 25 which is preferably of a U-shaped configuration. In the preferred embodiment of the score line 24, the U-shaped central portion 25 is concentric with the rivet 18 and disposed closely adjacent thereto. However, it is to be understood that other general U-shaped configurations may be utilized for the central portion 25 of the score line 24, including a generally pointed configuration. The score line 24 also includes reversely turned end portions 26 which are continuations of the central portion 25.

In accordance with this invention, when it is desired to open the container 10, the ring portion 23 is engaged with one's finger and lifted upwardly in the manner generally shown in FIG. 4. This results in the initial upward stressing of the end panel 13 in the area of the score line 24 prior to the stressing of the end panel 13 in the vicinity of the score line 16 sufficient to rupture the same along the score line 16. This initial stressing of the end panel 13 results in the rupture thereof along the score line 24 and the formation of a vent opening 27 which is in the form of a narrow slit. Normally the container 10 will be packaged at a negative pressure and accordingly the venting will be in the form of air flowing inwardly into the container, as is shown in FIG. 4. On the other hand, if the pressure within the container 10 is a positive one, the flow of air or gases will be outwardly. With respect to this, it is to be noted that the body 21 of the pull tab 20 overlies the vent opening 27.

Immediately following the venting of the container 10, as the pull tab 20 is moved upwardly in the manner shown in FIG. 5, there will be a further tearing of the end panel 13 along the score line 24 with that portion of the end panel 13 from which the rivet 18 is formed swinging upwardly and defining a hinge strip 28. The line of hinging of the strip 28 will be generally along the hinge line 29 of FIG. 3, which hinge line passes to one side of the rivet 18.

As the rivet 18 moves upwardly, it will also move radially outwardly with the nose 22 of the pull tab 20 likewise moving radially outwardly to a position aligned with the score line 16.

After the nose 22 is aligned with the score line 16 along the starting portion thereof, further upward movement of the pull tab 20 from the solid line position of FIG. 4 will result in the rupture of the end panel 13 along the score line 16 starting beneath the nose 22 and spreading in circumferentially opposite directions therefrom. As a result, with the continued upward swinging of the pull tab 20, the removable portion 17 of the end panel 13 will be forced down into the interior of the container 10, as is shown in dotted lines in FIG. 5, and the removable panel portion 17 will also hinge generally along the hinge line 29.

After the pull tab 20 reaches a generally upright position, as is shown in FIG. 5, it is pulled upwardly and generally to the right with the result that there is continued rupture of the end panel 13 along the score line 16 and the entire removable panel 17 is torn out.

From the foregoing description of the opening operation with respect to the container 10, it will be seen that the score line 24 provides for the three desired functions. First, as shown in FIG. 4, the initial rupture of the end panel 13 along the score line 14 results in the formation of the vent opening 27 so as to equalize the pressure between the interior of the container 10 and the atmosphere. This prevents any possibility of either an implosion or an explosion when the end panel 13 is ruptured along the score line 16 and in this manner an uncontrolled rupture of the end panel along the score line 16 is prevented. Secondly, with further tearing of the end panel 13 along the score line 24, a hinge for the pull tab 20 is formed from the material of the end panel 13, as is shown in FIG. 5. Also, as is shown in FIG. 5, the nose 22 of the pull tab 20 moves from an out-of-the-way position spaced radially inwardly from the starting portion of the score line 16 to a position aligned with the score line 16 ready to apply a rupturing force on the end panel 13 along the starting portion of the score line 16.

Referring once again to FIG. 3, it will be apparent that the reversely turned end portions 26 of the score line 24 assure against the accidental tearing of the end panel 13 from the score line 24 to the score line 16 with the resultant tearing out of a small portion of the end panel 13 as compared to the desired larger removable panel portion 17.

It will be obvious from the drawings and the aforegoing description that the pull tab 20, when initially lifted, as is shown in FIG. 4, pivots about the nose 22 and functions as a Class 2 lever in effecting the rupture of the end panel 13 along the score line 24. In a like manner, after the initial rupture of the end panel 13 along the score line 24, as hinging of the end panel occurs generally along the hinge line 29, the pull tab 20 has a center pivot along the hinge line 29 and thereafter functions as a Class 1 lever to effect the rupture of the end panel 13 along the score line 16 in the manner shown in FIG. 5.

Although the specific configuration of score line shown in FIG. 3 is preferred, it is to be understood that a modification of the score line is permissible within limits. In FIG. 6 there is illustrated a modified form of the score line, which is generally referred to by the numeral 31. When the score line has a configuration, such as that of the score line 31, the hinge line may be arcuate, such as is the hinge line 32, with the hinge line still passing to one side of the rivet 18.

It is to be understood that the score line configuration primarily requires the score line to be positioned where an initial rupture will occur in the general manner illustrated in FIG. 4 to effect the venting of the container and the equalization of the pressure therein with that of the atmosphere, followed by the formation of the equivalent of the hinge strip 28 with the nose 22 of the pull tab moving into alignment with the score line 16.

It will be readily apparent that other score line configurations may be utilized and it is the intent of applicant to cover all score line configurations which would be formed in accordance with the spirit and scope of the invention, as defined by the appended claims.