US3250425A - Rotatable pull tab to break scored tear strip - Google Patents

Description

May 10, 1966 F. J STEC ETAL 3,250,425

ROTATABLE PULL TAB TO BREAK SCORED TEAR STRIP Filed Feb. 17, 1964 INVENTORS YREDERWK J. STEC @"JOHN B.N\CHOLSON j Y W I m OREYS United States Patent York Filed Feb. 17, 1964, Ser. No. 345,434 Claims. (Cl. Mil-54) This invention relates in general to new and useful improvements in can ends of the easy opening type, and more particularly to a can end having means for facilitating the initial rupture of the end panel thereof as the first step in the tearing out of a removable portion of the end panel.

The customary easy opening can end presently in use is provided with a pull tab which is secured in place by means of a rivet formed integrally with the removable, portion of the can end. The mounting of a pull tab on such a can end meets with two conflicting requirements. In the first place, the pull tab must be so configurated and so mounted whereby it may be lifted to apply the initial rupturing force ,on the end panel. Secondly, the pull tab must be sufiiciently recessed within the can end so as to not in any way interfere with the handling of the can end and the can of which it is a part.

It is the customary practice to first form a can end with the pull tab attached thereto after which the can end is secured to a can body in a conventional double seaming operation. Therefore, it is necessary that the pull tab be of a size and so positioned whereby it in no way interferes with the handling of the can end utilizing normal can closing mechanism and the seaming of the can end to a can body utilizing such can closing mechanism. Then after the easy opening can end has been secured to the can body, the resultant can is transported in an inverted position with the easy opening can end temporarily forming the bottom of the can. The can is so positioned during the filling thereof and during the final closing thereof at which time a normal plain can end is secured to the then upper open end of the can. In the interest of economy, it is necessary that the recessing of the end panel of the can end he maintained at a minimum. Therefore, in order to assure that the pull tab does not interfere with the handling of the can end, the securement of the can end to a can body, and the handling of the can formed of the can body and the attached can end, it is necessary that the pull tab lie as close as possible to the surface of the end panel of the can end.

While it is desirable that the pull tab be, for all practical purposes, held in pressure contact with the end panel of an associated can end, it is also necessary that means he provided for facilitating the lifting of the pull tab to effect the initial rupture of the can end along the score line defining the removable portion thereof. Numerous tests have been conducted and on an average it has been found that 14 inch pounds of force is required to effect the initial rupture of the end panel of a can end utilized in the packaging of beer. Since the average pull tab has an effective length of one inch, it will be readily apparent that a lifting force of approximately 14 pounds must be exerted on the free end of the pull tab. Since the pull tab is preferably tightly clamped against the surface of the end panel, it will be seen that for all practical purposes one must place his of her fingernail beneath the free end of the pull tab and exert an upward force of 14 pounds therewith. This is very diflicult for many people to do. Furthermore, since often times the pull tab is provided with a raw edge, if ones fingers slips, during the opening process, a cut finger will result.

In addition to the foregoing, it will be readily apparcut that since the pull tab must be utilized in the tearing of the removable porion of the can end from the end panel thereof, even after the initial rupture of the can end has occured, it is necessary to retain the pull tab in an elevated position to facilitate the effective gripping thereof.

In view of the foregoing, it is the primary object of this invention to provide a can end of the easy opening type which includes a removable portion having attached thereto a pull tab in a manner whereby limited pivoting of the pull tab is permitted, the pull tab being normally disposed tightly against the upper surface of the end panel of the can end and the end panel being provided with a ramp-like projection generally aligned with the axis of the removable portion whereby when the pull tab is rotated, it will ride up on the ramp portion without any other lifting force being directed thereupon and will automatically effect the initial rupture of the end panel along the score line defining the removable portion.

Another object of this invention is to provide in an easy opening can end of the type including a pull tab mounted for pivotal movement means for automatically lifting the pull tab when it is pivoted whereby a sufiicient upwardly directed force is applied to the pull tab to effect the rupture of the can end along a weakening line thereof and at the same time the pull tab is held in an elevated posit-ion whereby it may be readily gripped to effect a tearing out operation on a removable portion of the can end to which the pull tab is secured.

Another object of this invention is to provide a novel can end of the easy opening type which includes a pull tab for facilitating the opening thereof, the can end being so constructed whereby the pull tab is normally tightly clamped against the upper surface of the end panel of the can end and when the pull tab is rotated into alignment with the removable portion of the can end to which the pull tab is attached, an upward movement of the pull tab is effected and an initial rupture of the end panel will occur.

A f-unther object of this invention is to facilitate the opening of existing types of easy opening containers by the provision of the end panel of each can end with a projection of the ramp type wherein when an associated pull tab is pivoted about a rivet securing the same to a removable portion of the can end, the pull tab will automatically be elevated and an initial rupture of the can end will occur.

A still further object of this invention is to provide an easy opening can end of the type which includes a pull tab for facilitating the opening thereof, the can end being so constructed whereby the pull tab may be readily lifted without applying a lifting force thereto, and the pull tab, after it has been lifted suificiently to eifect an initial rupture of the end panel will be held in an elevated position to facilitate the gripping thereof in a manner whereby the pull tab may then be utilized for the tearing of a removable portion of the can end therefrom.

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:

FIGURE 1 is a top perspective View of an easy opening can formed in accordance with this invention and shows the specific details of the easy opening can end thereof.

FIGURE 2 is a top perspective view similar to FIG- URE 1 and shows the pull tab of the can end rotated to a position wherein initial rupture of the end panel of the can end occurs.

FIGURE 3 is an enlarged fragmentary vertical sectional View taken along the line 33 of FIGUREZ and shows specifically the details of the can end construction for elfectingthe lifting of the pull tab when the pull tab is rotated and the resultant initial rupturing of the end panel.

FIGURE 4 is an enlarged fragmentary transverse vertical sectional view taken along the line 44 of FIG- URE 3 and shows specifically the relationship of the pull tab and a projection of the ramp type formed in the end panel to effect the lifting of the pull tab when the pull tab is rotated.

Referring now to the drawing in detail, it will be seen that there is illustrated a can of the easy open-ing type, the can being generally referred to by the numeral 5. The can 5 includes a conventional can body 6 to which there has been attached by means of a double seam 7 an easy opening can end which is .generally referred to by the numeral 8.

The can end 8 for the most part is of a conventional construction and includes an end panel 9. The end panel 9 has a removable portion 10 which is defined by a score line 1-1. The removable portion 10 includes a starting part 12 which is provided with an integral rivet 13. The rivet 13 is utilized to secure a pull tab 14 to the starting part 12.

The can end 8 as described above incorporates conventional features and is difiicult to open. In order that the pull tab 14 in no way interferes with any operation to be performed in either the making of the can 5, the filling of the can 5 or the closing thereof, it is necessary that the pull tab 14 be clamped tightly against the upper surface of the end panel 9. On the other hand, it is necessaryto lift the pull tab 14 in order to effect an initial rupture of the end panel 9 along the score line 11 immediately adjacent the rivet 13. It will be readily apparent that if the pull tab 14 is tightly clamped against the end panel 9, it will be extremely difficult to exert a lifting force on the pull tab 14 with ones finger. It has been found that in cans of the type illustrated in the drawing, a force of approximately 14 pounds is required to lift the pull tab 14 and effect an initial rupturing of the end panel 9. Since there is very little available gripping surface, it will be readily apparent that it is extremely difilcult for most people to lift the pull tab 14. Furthermore, often times there is relative slippage between the pull tab and ones finger and should an exposed raw edge be contacted by ones finger at the time the slippage occurs, then ones fingers are cut. Accordingly, while the above-described pull tab arrangement has been satisfactory to a certain extent, it has many deficiencies, and has met with numerous objections.

In accordance with this invention, the pull tab 14 is initially disposed at an angle to the axis of the removable p-o'trion 10 with the illustrated angle of FIGURE 1 being approximately 90 degrees to the axis of the removable portion v10. The end panel 9 is then modified to be provided with an upwardly directed projection 15. The projection 15 has an arcuate outline with its center being generally the axis of the rivet 13. The projection 15, as is best illustrated in FIGURE 4, is provided at the opposite ends thereof with upwardly sloping ramps 16.

It will be readily apparent from the showings of FIG- URES 1, 2 and 4 that when the pull tab .14 is rotated from the position shown in FIGURE 1 to a position aligned with the removable portion 10, as is shown in FIGURE 2, the pull tab 14 will automatically ride up one the r-amps ld onto the top of the projection 15 to the position shown in FIGURE 4. This will result in a sufiicient upwardly directed force to effect rupture of the end panel 9 along the score line 11 at the starting end of the removable portion 10.

It will also be apparent from FIGURE 3 that after the initial rupture of the end panel 9 along the score line 11 occurs, the pull tab 14 remains elevated above the end panel 9 sufiiciently for one to effectively grip the pull tab and exert therewith a tearing force on the removable portion 1%) to tear. the same from the remainder of the end panel 9 along the score line 11. Thus the projection 15 not only permits the initial rupture of the end panel to be brought about by a mere swinging or pivoting of the pull tab 14, but also greatly facilitates the complete tearing out of the removable portion 10.

In the past it has been proposed to utilize the upstanding seam of a can as a camming surface for the'lifting of a pull tab. However, it will be readily apparent that since the pull tab is pivotally connected at the center of the can end, it is impossible to have the pull tab stored within the confines of the can end and at the same time be movable to a position overlying the seam of the can. Secondly, even if such a relationship were possible, it will be readily apparent that it is still necessary to initially lift the pull tab to a position where it overlies the seam. This is undesirable. With the disclosed pull tab and can end arrangement, it is merely necessary for one to push the pull tab 14 with ones finger so that it rotates about the axis of the rivet 13 and gradually rides up onto the projection 15. Inasmuch as the edges of the pull tab may be protected by forming the same with a turned hem, it willbe readily apparent that the pull tab 14 will have no exposed surfaces which may be engaged by ones fingers during the pivoting of the pull tab. Furthermore, as pointed out above, the pull tab remains in an elevated position after the initial rupture of the end panel 9 so that the pull tab 14 may be firmly gripped for the purpose of completing the removal of the removable portion 10. A further obvious advantage of the can end and pull tab arrangement is that since the pull tab does not have to be lifted whatsoever, it may be clamped fiat against the upper surface of'the end panel 9 and thus there is no problem of the pull tab undesirably engaging the machinery utilized in applying the can end 8 to the can body 6 or the machinery for handling, filling and closing the can 5.

Although only a preferred embodiment of the invention has been specifically illustrated and described herein, it is to be understood that minor modifications may be made in the disclosed can end construction within the spirit and scope of the invention, as defined by the appended claims.

We claim:

1. An easy opening container element having a removable portion defined by a weakening line, said removable portion including a starting portion, a pull tab, a fastener securing said pull tab to said starting portion for effecting the rupture of said container element along said weakening line and for limit-ed pivotal movement of said pull tab, and said container element having a projection disposed radially outwardly of said weakening line in the path of pivotal movement of said pull tab and adapted to be engaged by said pull tab, said projection including a terminal ramp generally opposing said pull tab whereby when said pull tab is pivoted against said projection, said pull tab will ride up said ramp and onto said projection thereby placing a lifting force on said starting portion through said fastener sufiicient to effect an initial rupture of the container element.

2. The container construction of claim 1 wherein that portion of said container element to which said pull tab is secured is generally flat and said pull tab. is clamped tightly thereagainst.

3. The container construction of claim 1 wherein said projection is in axial alignment with said removable portion.

4. The container construction of claim 1 wherein said projection is arcuate in outline and has the center of said fastener as a center of curvature.

5. A container end of the easy opening type comprising an end panel and an upstanding surrounding seam forming portion, said end panel having a removable por tion defined by a weakening line, said removable portion including a starting portion, a pull tab fully seated within said container end, a fastener securing said pull tab to said starting portion for pivotal movement, said end panel having a projection disposed radially outwardly of said weakening line in the path of pivotal movement of said pull tab, said projection including a terminal ramp generally opposing said pull tab whereby when said pull tab is pivoted against said projection said pull tab will ride up said ramp and onto said projection thereby lifting said pull tab and placing a lifting force on said starting portion through said fastener sufiicient to effect an initial rupture of said end panel.

6. The container end of claim 5 wherein said pull tab is tightly clamped against said end panel by said fastener.

7. The container end of claim 5 wherein said projection is in axial alignment with said removable portion.

8. The container end of claim 5 wherein the distance between the center of said fastener and all parts of said seam forming portion is greater than the distance from the center of said fastener to a remote end of said pull tab whereby said pull tab cannot engage said seam forming portion.

9. The container end of claim 5 wherein said container end is circular and said fastener is centrally positioned.

10. The container end of claim 5 wherein said projection is arcuate in outline and has the center of said fastener as a center of curvature.

THERON E. CONDON, Primary Examiner. G. T. HALL, Assistant Examiner.

Claims (1)

1. AN EASY OPENING CONTAINER ELEMENT HAVING A REMOVABLE PORTION DEFINED BY A WEAKENING LINE, SAID REMOVABLE PORTION INCLUDING A STARTING PORTION, A PULL TAB, A FASTENER SECURING SAID PULL TAB TO SAID STARTING PORTION FOR EFFECTING THE RUPTURE OF SAID CONTAINER ELEMENT ALONG SAID WEAKENING LINE AND FOR LIMITED PIVOTAL MOVEMENT OF SAID PULL TAB, AND SAID CONTAINER ELEMENT HAVING A PROJECTION DISPSOED RADIALLY OUTWARDLY OF SAID WEAKENING LINE IN THE PATH OF PIVOTAL MOVEMENT OF SAID PULL TAB AND ADAPTED TO BE ENGAGED BY SAID PULL TAB, SAID PROJECTION INCLUDING A TERMINAL RAMP GENERALLY OPPOSING SAID PULL TAB WHEREBY WHEN SAID PULL TAB IS PIVOTED AGAINST SAID PROJECTION, SAID PULL TAB WILL RIDE UP SAID RAMP AND ONTO SAID PROJECTION THEREBY PLACING A LIFTING FORCE ON SAID STARTING PORTION THROUGH SAID FASTENER SUFFICIENT TO EFFECT AN INITIAL RUPTURE OF THE CONTAINER ELEMENT.

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