US3445029A

US3445029A - Container having integral tear strip opening means

Info

Publication number: US3445029A
Application number: US733618A
Authority: US
Inventors: Richard D Zenger
Original assignee: National Can Corp
Current assignee: Rexam Beverage Can Co
Priority date: 1968-05-31
Filing date: 1968-05-31
Publication date: 1969-05-20
Anticipated expiration: 1986-05-20

Description

y 0, 1969 R. D. ZENGER 3,445,029

CONTAINER HAVING INTEGRAL TEAR STRIP OPENING MEANS Filed May 31, 1968 Sheet of 2 lr z ve ntor Richard D. Zenger B 1Q y 0, 1969 R. D. ZENGER 3,445,029

CONTAINER HAVING INTEGRAL TEAR STRIP OPENING MEANS Filed May 51, 1968 Sheet 3 of 2 Inventor Richard .D. Zenser B @40 9 149449? A-l-L'orne Q/ United States Patent 015cc 3,445,029 Patented May 20, 1969 3,445,029 CDNTAINER HAVING INTEGRAL TEAR STRIP OPENING MEANS Richard D. Zenger, Downers Grove, Ill., assignor to National Can Corporation, Chicago, 11]., a corporation of Delaware Filed May 31, 1968, Ser. No. 733,618 Int. Cl. B65d 17/20 U.S. Cl. 22054 12 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to an easy opening container end and particularly of the type provided with a weakened score line portion defining a tear out strip to which is connected a pull means wherein the pull means initiates tearing of such tear out strip by means of a second class lever and fulcrum action. The lever fulcrum portion of the present structure is bendable or otherwise somewhat resilient so as to avoid an undesirable creasing and resultant transverse fracture of the tear strip which may occur with easy open end constructions utilizing rigid second class lever pull means. The tear strip section of the present structure may also be provided with a longitudinally orientated groove or nib which serves to stiffen that area of the tear strip upon which the fulcrum is designed to act.

BACKGROUND OF THE INVENTION Containers having so called easy open ends have become Well known in the past several years and now enjoy a high measure of consumer acceptability. These container ends generally are provided with an end panel having a. score line area therein defining a weakened portion or tear strip which may be torn from the remainder of the panel so as to provide an opening to the contents of the container. The tearing action is initiated generally by a lever means in the form of a tab such as shown by U.S. Patent 3,225,957 to Huth or in the form of a ring pull as shown by U.S. Patent 3,3 49,949 to Brown et al. Both the tab and ring pull mechanisms of this style easy open end may be affixed to a portion of the tear strip by means of a hollow rivet structure integral with such tear strip as shown by the aforementioned 949 patent or alternatively by means of a solid rivet such as shown in U.S. Patent 3,383,008 to Lipske.

Many of the pull or tab means now available commercially in effect operate as second class levers to initiate tearing of the tear strip from the remainder of the end panel. By reason of such pull or tab mechanism acting as a second class lever, the geometry of such pull means requires its fulcrum point be on the opposite side of the pull means from the point at which it is attached to the tear strip portion. Thus, when the pull means and the tear strip are generally aligned with each other, pull means having centrally located fulcrums will overlie a portion of the tear strip at an intermediate portion thereof. In such devices When the tearing of the tear strip is initiated by pivotal movement of the pull or tab means, the fulcrum thereof transversely contacts such intermediate portion of the tear strip and in many cases may cause a crease thereacross. This crease will be formed along a relatively thin transverse portion of the tear strip and will accordingly receive a significant portion of the force moment created by the tear initiating pivotal movement of the pull means. Such a crease in effect sets up a fracture line across which the material forming the tear strip may break causing an obviously undesirable situation Where only a portion of the tear strip is removed from the remainder of the panel. The severity of this problem is directly dependent, however, upon the malleability, brittleness and thickness of the material comprising the tear strip. Thus, the potential problem is increased as the malleability, thickness and flexibility of the tear strip stock is decreased.

The problem indicated above has been particularly observed in regard to those pull means levers utilizing a fulcrum which essentially wholly bears transversely across an intermediate portion of the tear strip as distinguished from lever structures which are provided with a fulcrum or fulcrum points bearing upon portions of the end panel itself either entirely or in addition to bearing upon the tear strip. An example of a lever structure having fulcrum points in the form of leg extensions which straddle the tear strip and thus entirely act upon the end panel itself is shown in U.S. Patent 2,978,140 to Walsh.

The present invention provides a satisfactory solution to the above indicated problems is thus particularly directed to second class lever structures provided with fulcrum means which contact and act upon tear strip portions and particularly those that are provided with a fulcrum which contacts and acts upon a major transverse portion of the tear strip portion.

SUMMARY The novel construction for an easy open end of this invention includes the use of a fulcrum which is bendable or otherwise yieldable so that such fulcrum in effect operates on a longitudinal zone of the tear strip rather than a transverse line thereof so as to distribute the pivotal moment force of the lever and accordingly prevent undesirable fracture of the tear strip. It is also found that transverse creasing and ultimate fracture of the tear strip may be prevented through the use of a longitudinally orientated nib or groove in combination with such bendable fulcrum construction. Such nib or groove is located within the tear strip itself so as to stiffen that intermediate portion of the tear strip which is acted upon by the fulcrum.

Such construction comprises an end panel having a weakened line defining the removable tear strip wherein the tear strip includes an end portion having a tear initiating section, a second class lever attached to said tear initiating section, said lever having a fulcrum positioned above said tear strip adjacent to the tear initiating section, and wherein the fulcrum is longitudinally bendable when transversely contacting the tear strip upon pivoting of the lever to initiate and advance tearing of the tear strip from the remainder of the end panel. Accordingly, it is an object of the present invention to provide a novel container end opening construction of this type wherein the aforementioned undesirable features of prior art constructions are avoided.

It is a further object of this invention to provide novel structure for an easy open container end which is of relatively simple construction and which lends itself to present high speed manufacturing techniques.

Other objects and advantages of the invention will become apparent from the following portion of the specification, the claims and the attached drawings.

DESCRIPTION OF THE DRAWINGS FIGURE 1 is a fragmentary top perspective view of a container having the easy open end construction of the present invention.

FIGURE 2 is an enlarged fragmentary plan view of a portion of the can end of FIGURE 1 and shows specifically one embodiment of a bendable fulcrum formed by weakening slits in the end portion of the pull means thereof.

FIGURE 3 is an enlarged fragmentary sectional view taken through the upper part of the can end of FIGURE 1 representing prior are construction and shows the manner of initiating tearing of the tear strip from the remainder of the end panel wherein a crease is formed transversely across the tear strip section at which crease, fracture may frequently occur.

FIGURE 4 is a fragmentary sectional view similar to that of FIGURE 3 but showing the beneficial effect thereon of the structure of the present invention.

FIGURE 5 is an enlarged fragmentary sectional view similar to FIGURE 4 and depicting in particular the stiffening effect of the intermediate portion of the tear strip brought about by the presence of the longitudinally orientated nib therein.

FIGURE 6 is an enlarged fragmentary plan view similar to FIGURE 2 of the drawings disclosing an alternate embodiment of the present fulcrum construction.

FIGURE 7 is an enlarged fragmentary plan view similar to FIGURE 6 of the drawings but showing a still further alternate embodiment wherein the fulcrum is provided with transverse corrugations.

DESCRHTION Referring to the drawings and more particularly to FIGURE 1, there is therein illustrated a can having an easy open end in accordance with the present invention. The can 10 includes a can body 11 of conventional construction which has the lower end thereof closed in the normal manner either by an integral end or an end separately secured thereto.

The upper end of the can body 11 is closed by means of an easy opening end, generally referred to be the reference numeral 12, the can end 12 being secured to the can body 11 by means of the conventional double seam 13. The can end 12 is provided with

score lines

14 and 15 which define a closed tear out section or tear strip 16. The tear strip 16 is in turn composed of a major open portion 17, and intermediate portion 1 8 and a tear initiating section 19.

The tear initiating portion 19 of the tear o'ut section 1 6 may also be provided as shown with an integral rivet 20 to which a pull means such as ring pull 21 is secured. Furthermore a pair of short upstanding shallow ribs 22 are provided adjacent the opposite sides of the tear strip to stiffen the can top 12 so as to facilitate the final severance of the tear strip therefrom and also to in effect depress the opening formed by removal of the tear strip 16 away from the lips of a user should the contents of the can be drank directly therefrom.

The ring pull 21 is in turn provided with a handle portion 24, a connecting portion 26 and an end portion 28. Such ring pull may be formed from sheet metal which has been stamped or otherwise formed to present the construction depicted. An opening for receipt of the rivet 20 is provided in the connecting sector 26 of the ring pull 21 which best may be seen by reference to FIG- URES 3, 4 and 5 of the drawings wherein the rivet is shown as being headed over to entrap that part of the connecting portion surrounding the rivet receiving opening and thus connect the ring pull to the tear strip.

Referring now more particularly to FIGURE 2 of the drawings the end portion 28 of the ring pull 21 is shown as being provided with a pair of spaced longitudinal weakening slits 32 therein. Such slits are shown generally overlying and aligned with the

score lines

14 and 15 in the intermediate portion of 18 of the tear strip 16. The presence of these slits 32 in effect form a weakened and upwardly bendable fulcrum F from the outer portion of the end 28.

The effect of this thus weakened fulcrum F by the provision of the slits 32 is best shown by reference to a comparison of FIGURES 3 and 4 of the drawings. FIGURE 3 thus depicts an undesirable construction wherein a generally rigid fulcrum of a second class lever transversely contacts a very minor longitudinal portion of the tear strip 16 in such a manner so as to essentially form a line crease thereacross. Such a line crease forces the torn portion of the tear strip represented by the tea initiating portion 19 to bend sharply adjacent such crease so as to form a sharp radius bend therein which accordingly may result in the fracture thereof. Such fracture undesirably results in only a portion of the tear strip 16 being removed from the end panel. Thus, the major portion of the tear strip remains in the end panel while the tear initiating portion being severed therefrom remains attached to the ring pull.

The provision of the bendable fulcrum of the present invention as shown in FIGURE 4 of the drawings prevents the transverse creasing of the tear strip by permitting the fulcrum to bend upwardly from an unbent position represented by the dotted lines to the full line showing upon the tear initiating pivoting of the pull means so as to bring about a sliding contact between the fulcrum and the tear strip. Thus, as the tearing advances the fulcrum will upwardly bend in such a manner so as to exert the force moment transmitted to the tear strip over a longitudinally orientated segment thereof rather than in a select transverse line thereof. Thus, it may be seen that the bend within the intermediate portion of the tear strip is of a much greater radius and accordingly presents less opportunity for an undesirable fracture to occur in such section.

In addition to the provision of a weakened or bendable fulcrum F as through the provision of slits 32 it is often desirable as shown in FIGURES 1 and 2 of the drawings to incorporate within the tear strip 16 a longitudinally orientated nib 34. This nib 34 may be in the form of a depression as shown in FIGURE 5 of the drawings or alternatively may extend above the major plane of the tear strip. As may best be seen from the drawings, the nib 34 is formed generally centrally between the

score lines

14 and 15 within the intermediate portion 18 of the tear strip 16. The fulcrum F is positioned so as to overlie that portion of the tear strip in which the nib is provided. The nib 34 in turn stiifens the intermediate section 18 of the tear strip so as to further enable such portion to resist transverse bending. The combination of the weakened fulcrum F and the stiffening nib 34 has been found to be extremely effective in reducing fracture of the tear strip caused by sharp radius bending thereof during the tear initiating and initial removal sequences of the tear strip 16 from the can end 12.

Turning now to FIGURE 6 of the drawings, a modified form of weakened fulcrum construction is therein depicted. The ring pull 21 is provided with a narrowed projection 36 extending from the end portion 28 thereof. This projection 36 preferably lies wholly between the score lines 14 and 15 and is of a transverse extent equal to the major portion of the tear strip at the intermediate portion 18 thereof. The fulcrum formed by the extension 36 by reason of its relatively narrow extent is upwardly bendable during its pivotal contact with the tear strip when removal thereof from the can end is initiated and during the advance tearing thereof.

In a similar fashion as is accomplished by the provision of the weakening slits 32 shown in the previous drawings a further modification to increase the bendability or flexibility of the projection 36 is shown in FIGURE 7. Therein, the projection 36 is provided with a series of transverse corrugations or slits 38. In this manner then the projection 36 is further weakened so as to facilitate an enhanced upward bending thereof upon pivotal contact with the tear strip.

From the foregoing it may be seen that alternate novel structure for accomplishing the removal of a tear strip from an easy open end has been set forth and that such structure avoids undesirable partial fracture of such tear strips.

I claim:

1. An easy open end for a container, said container comprising:

an end panel having a weakened line defining a re- 5 movable tear strip, said tear strip including an end portion having a tear initiating section,

pull means in the form of a second class lever attached to said tear initiating section,

said lever having a fulcrum position above said tear strip and adjacent said tear initiating section,

said fulcrum being longitudinally bendable when transversely contacting said tear strip upon pivoting of said level to initiate and advance the tearing of said tear strip from the remainder of said end panel.

2. The can end of claim 1 wherein that portion of the tear strip underlying the fulcrum and adjacent said tear initiating section is provided with a longitudinally orientated tear strip stiffening nib.

3. An easy open end for a container, said container comprising:

an end panel having a weakened line defining a removable tear strip,

said tear strip including an end portion having a tear initiating section to which pull means are attached, said pull means comprising a second class lever having a handle portion and an end portion, said lever end portion including a fulcrum about which said pull means is pivoted to initiate tearing of said tear strip, connecting means for securing a portion of said pull means intermediate said handle and said end portions to said tear initiating section of said tear strip,

said lever end portion and the fulcrum thereof positioned above said tear strip and adjacent said tear initiating section,

said fulcrum being longitudinally bendable and laterally spanning a major portion of said tear strip.

4. The can end of claim 3 wherein said fulcrum lies wholly within the confines of said tear strip.

5. The can end of claim 3 wherein said fulcrum comprises a weakened portion of said end portion lying between a pair of spaced longitudinal slits, said slits being generally aligned With the weakened line portions of the underlying tear strip.

6. The can end of claim 3 wherein said fulcrum comprises a narrowed extension of said end portion, said extension solely overlying said tear strip and of a lesser planar extent.

7. The can end of claim 6 wherein said extension is provided with at least one transversely orientated weakened portion.

8. The can end of claim 7 wherein said transversely orientated weakened portion comprises a series of spaced corrugations.

9. An easy open end for a container, said container comprising:

an end panel having a weakened line defining a removable tear strip,

said tear strip having a major open portion, an end portion and an intermediate portion therebetween,

said tear strip end portion having a tear initiating section to which pull means are connected,

said pull means comprising a second class lever having a handle portion and an end portion,

said lever end portion including a fulcrum about which said pull means is pivoted to initiate tearing of said tear strip,

connecting means for securing a portion of said pull means intermediate said handle and said end portion to said tear initiating section of said tear strip,

a longitudinally orientated tear strip stiffening nib located generally centrally of said intermediate portion of said tear strip,

said level end portion positioned above said intermediate portion of said tear strip and bridging said nib,

said fulcrum being longitudinally bendable and lateral- 1y spanning a major portion of said tear strip.

10. The can end of claim 9 wherein said fulcrum lies Wholly within the confines of said tear strip.

11. The can end of claim 9 wherein said fulcrum comprises a weakened portion of said end portion lying between a pair of spaced longitudinal slits, said slits being generally aligned with the weakened line portions of the underlying tear strip.

12. The can end of claim 9 wherein said fulcrum comprises a narrowed extension of said end portion, said extension solely overlying said tear strip and of a lesser planar extent.

References Cited UNITED STATES PATENTS 3,401,822 9/1968 Fraze 220-54 3,401,824 9/1968 Rouse 22054 GEORGE T. HALL, Primary Examiner.