US3880318A

US3880318A - Reinforced easy opening end structure

Info

Publication number: US3880318A
Application number: US422664A
Authority: US
Inventors: Ermal C Fraze
Original assignee: Individual
Current assignee: Dayton Reliable Tool and Manufacturing Co
Priority date: 1973-12-07
Filing date: 1973-12-07
Publication date: 1975-04-29
Anticipated expiration: 1992-04-29

Abstract

Easy opening ends for containers, particularly containers of the full panel pull out variety, include an end wall having a protective guard means which cooperates with the score line. A tab including a nose and lifting end is affixed to the end wall by an integral rivet, the nose of the tab being adjacent to the score line, while the lifting end extends towards the center of the end wall. The end wall includes a stiffening structure located beneath the tab and adjacent to the rivet to prevent upward flexing of that portion of the end wall in the immediate vicinity of the integral rivet, such flexing tending to permit radially inward movement of said tab out of operative rupturing position with respect to the score line. The stiffening structure in the end wall may take various forms each of which operates as a reinforcing component for a localized portion of the end wall. For example, the stiffening structure may include a pair of spaced angularly disposed depressions which extend downwardly or towards the non-public side of the end wall. In another form an arcuate ridge, in the form of a raised portion, includes spaced legs positioned adjacent to the rivet for reinforcing that portion of the end wall underlying the lifting end of the tab. As a variant, the stiffening structure may include a raised bead operative to prevent the lifting end of the tab from being grasped by the user until it has been raised sufficiently to initiate rupture of the score line. Various other forms of stiffening structures are described.

Description

United States Patent 1191 Fraze REINFORCED EASY OPENING END STRUCTURE [76] Inventor: Ermal C. Fraze, 355 W. Stroop Rd..

Dayton. Ohio 45429 22 Filed: Dec. 7, 1973 21 1 Appl. No.: 422.664

Primary Examiner-George T. Hall Attorney, Agent, or Firm-George F. Smyth [57] ABSTRACT Easy opening ends for containers. particularly containers of the full panel pull out variety, include an end wall having a protective guard means which cooper- 111 3,880,318 (451 Apr. 29, 1975 ates with the score line. A tab including a nose and lifting end is affixed to the end wall by an integral rivet. the nose of the tab being adjacent to the score line. while the lifting end extends towards the center of the end wall. The end wall includes a stiffening structure located beneath the tab and adjacent to the rivet to prevent upward flexing of that portion of the end wall in the immediate vicinity of the integral rivet. such flexing tending to permit radially inward movement of said tab out of operative rupturing position with respect to the score line. The stiffening structure in the end wall may take various forms each of which operates as a reinforcing component for a localized portion of the end wall. For example. the stiffening structure may include a pair of spaced angularly disposed depressions which extend downwardly or towards the non-public side of the end wall. In another form an arcuate ridge. in the form of a raised portion. includes spaced legs positioned adjacent to the rivet for reinforcing that portion of the end wall underlying the lifting end of the tab. As a variant. the stiffening structure may include a raised bead operative to prevent the lifting end of the tab from being grasped by the user until it has been raised sufficiently to initiate rupture of the score line. Various other forms of stiffening structures are described.

21 Claims, 12 Drawing Figures REINFORCED EASY OPENING END STRUCTURE CROSS-REFERENCE TO RELATED APPLICATIONS Reference is made to US. application Ser. No. 236.654, filed Mar. 2l, I972; U.S. application Ser. No. 336,404, filed Feb. 28. I973; and US. Pat. No. 3.765.352. issued Oct. 16. 1973'. all assigned to the same assignee.

BACKGROUND OF THE INVENTION This invention relates to easy opening ends for containers and. more specifically, to an improved easy opening end. preferably of the full panel pull-out type. in which the end wall includes a stiffening structure to prevent radially inward movement of the nose of the tab structure relative to a score line in response to attempted movement of the lifting end of the tab structure radially away from the score line and upwardly.

The ready acceptance of easy opening containers has resulted in extended use of this type of container for a substantial number of products, especially beverages. such as beer. soft drinks and the like. as well as other comestible products. In addition to the easy opening container of the beverage type. the convenience of the easy opening feature has led to the use of a container known in the trade as a full panel pull out.

In contrast to the beverage type convenience container. the full panel pull out is structured such that substantially the entire end wall of the container is removed in use. US. Pat. No. 3.765.352, supra. is illustrative of one form of full panel pull out container.

As will be appreciated, the differences in structure between the beverage container and the full panel pull out have created some problems in connection with the respective opening operations performed by the user in fracturing the score line.

In the case of a full panel pull out container, the end wall usually includes a longitudinally rigid tab structure having a nose end and a lifting end. the tab being secured to the end wall such that the nose of the tab is positioned adjacent to the score line, the latter normally extending all the way around the end wall to define the panel which is removed. In opening this type of container. it is intended that the user raise the lifting end of the tab so as to bring the nose thereof downwardly into the score line to effect initial rupture of the score line. Normally. the score line is ruptured as the lifting end of the tab reaches an angle of between and with respect to the plane of the end wall. After initial rupture of the score line, the lifting end of the tab is raised further to somewhere between a 60 and 85 angle from the plane of the end wall, and the tab is pulled outwardly in order to effect removal of the full panel.

Where the end wall of the panel includes a protective guard means of the type described in US. Pat. No. 3.765.352, or U.S. application Ser. No. 236.654. it has been determined that improper initial manipulation of the lifting end of the tab can lead to failure of the opening operation. In essence, the failure mode appears to be derived from the fact that the user, rather than lifting the end of the tab from a generally horizontal plane to a vertical plane. sometimes attempts to lift the tab sufficiently off the end wall such that the finger can be inserted through the finger hole of the tab. Thereafter. the user attempts to pull the tab radially inwardly towards the center of the container. or stated differently. tends to pull the nose of the tab away from the score line. In some structures. this is possible because that portion of the end wall immediately adjacent to the rivet bulges upwardly as the tab end is raised somewhat less than the 20 to 30 needed to effect initial rupture of the score line and pulled radially toward the center of the end wall.

With the tab end positioned slightly above the end wall. but not raised sufficiently to affect rupture of the score line. the user tends to pull on the tab in an attempt physically to tear out the full panel completely rather than to initiate the initial rupture of the score line.

Where the end wall of the full panel includes a protective guard. the guard generally is associated with the score line. Thus. as the user tends to pull the nose of the tab radially inwardly and simultaneously lifts the free end of the tab. the nose of the tab becomes caught on the guard. Continued movement of the free end of the tab toward the vertical position is unsuccessful in rupturing the score line. because the nose of the tab is no longer in operative position with respect to the score line.

It has been determined that the principal reason for radially inwardly movement of the nose of the tab under the conditions described. is at least in part due to the ability of the end wall in the area immediately surrounding the rivet to be flexed during the initial small upward and radial inward movement of the free end of the tab.

As will be appreciated. inadvertent improper operation of the tab during an opening operation of a full panel pull out container can create serious problems of public acceptance. especially if there are a substantial number of cans in circulation and the failure rate due to improper operation is in the range of 4percent to Spercent.

While it is true that public education may overcome the problem. a more practical approach is to provide an end structure in which imporper operation is prevented.

SUMMARY OF THE INVENTION The present invention relates to an easy open container. arid an end for such a container, and particularly to an end structure of the full panel pull out variety which overcomes the problem previously described.

In an exemplary embodiment of the present invention. the end wall of an easy opening container is provided with strengthening means located in the vicinity of the rivet normally used to affix a tab to the end wall. The tab itself usually is of the type which is longitudinally rigid, having a nose end and a lifting end. with the tab being affixed to the end wall by a rivet. the tab normally being attached at a point between the nose and the lifting end. The strengthening means are positioned on that portion of the end wall immediately beneath the lifting end of the tab and in that portion of the end wall adjacent to the rivet.

In one form. the strengthening means includes deformations formed in the end wall. the deformations being configured to provide a reinforcement in that portion of the end wall which tends to bulge during an improper opening sequence of the end structure.

By the present invention. the strengthening means may take anyone of several forms. for example, a pair of angularly disposed and spaced depressions may be formed in the end wall in the area adjacent to the rivet. the depressions extending downwardly and acting as reinforcing beams to prevent the bulging which tends to take place during an improper opening sequence.

In another form. the strengthening means may be in the form of an arcuate raised portion generally surrounding the tab and including spaced legs which extend towards the score line. With this latter form of reinforcing means, it is also posssible to form into the end wall in the area thereof underlying the lifting end of the tab a raised projection which cooperates with the tab so as to prevent insertion of the users finger through the tab until the lifting end thereof has been raised sufficiently to initiate fracture of the score line.

The form above described may be modified still further such that the strengthening means also functions to prevent the user from inserting a finger through the finger hole of the lifting end of the tab until the tab has been raised sufficiently from the end wall to initiate fracture of the score line.

Regardless of the specific form of strengthening means used in the end wall for the purpose of preventing radially inward movement of the nose of the tab during an improper opening sequence, the advantages of the use of such strengthening means are significant. For example, in those end structures incorporating a protective guard means to prevent laceration by the free edge of the removal panel, failure of the end structures incorporating a protective guard means to prevent laceration by the free edge of the removal panel, failure of the end structure to open properly is aggravated by the fact that the nose of the tab, if displaced inwardly towards the center of the container, tends to become locked such that continued upward movement of the lifting end of the tab stresses the rivet structure sufficiently to cause removal of the tab from the end panel. In such a circumstance. the user's reaction is that the end structure is poorly designed and inoperative. However. the fact is that the user has attempted to open the end structure in a manner other than that contemplated by the design thereof.

In addition to the guard means previously mentioned. many of the full panel pull out type end structures also include a weakening lines so positioned in the end wall as to provide a hinging function in the normal operation of the end, as the free end of the tab is lifted to initiate rupture of the score line. Depending on the specific design of the particular end structure in question, the hinge line is so located as to provide the proper hinging action with respect to the location of the principal score line and the particular structure of the tab being used. Thus. if in an improper opening operation the nose of the tab is moved radially inwardly, the geometry of the designed hinging operation is effectively destroyed and therefore. an improper folding or hinging action occurs which only further frustrates the sequence of events which should take place in a normal opening operation.

Where a full panel pull out type end structure incorporates both a protective guard associated with the principal score line and a secondary type score which functions. at least in part, as a hinge during the normal opening sequence, it is desirable to prevent radially inward movement of the nose of the tab in those end structures in which the design of the tab is such that in a normal opening operation it is intended that the nose pivot downwardly into engagement with the score line. or to pivot downwardly and move forward towards the score line in response to movement of the lifting end.

It will be apparent that other advantages and modes will be readily understood by those skilled in the art after they have read the detailed description and have referred to the accompanying drawings which illustrate what are presently considered to be preferred embodiments of the best mode contemplated for utilizing the novel and improved structure set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1-3 illustrate a now conventional easy opening end structure of the full pull out panel variety and are helpful in understanding the nature of the problem solved by the present invention;

FIG. 4 is a plan view of an easy opening end in accordance with the present invention illustrating the position and structure of one form of strengthening means in accordance with the present invention;

FIG. 5 is a view in section of the container end illustrated in FIG. 4, taken along the lines 5-5 of FIG. 4;

FIG. 6 is an enlarged fragmentary view of a portion of the container end structure illustrated in FIG. 7 showing the details of the strengthening means in accordance with the present invention;

FIG. 7 is a plan view of a container end in accordance with the present invention showing another form of stiffening means in the end structure. and showing an additional feature of the present invention by which the user is prevented from inserting a finger through the finger hole of the tab until the lifting end of the tab has been raised sufficiently to initiate rupture of the principal score line;

FIG. 8 is an enlarged sectional view, partly in perpsective taken along the line 88 of FIG. 7;

FIG. 9 is an enlarged fragmentary view of a portion of the end structure illustrated in FIG. 7 showing the details of the strengthening means in accordance with the present invention;

FIG. 10 is a plan view of another form of container end wall structure in accordance with the present invention;

FIG. 11 is an enlarged fregmentary view partly in section and partly in elevation taken along the line 11-11 of FIG. 10; and

FIG. 12 is an enlarged fragmentary view. in perspective, of a portion of the end structure illustrated in FIG. 10.

DETAILED DESCRIPTION Referring to FIGS. 1-3, a typical container 10 and end structure 12 are shown of the full panel pull out type. The end structure 12 a chime l3 seamed to a can body 14, the latter illustrated fragmentarily.

The end structure 12 includes a principal score line 15 which defines the panel 17 removed in order to open the container. As shown, the score line 15 is preferably continuous and in the usual form is generally circular in shape. although it is to be understood that the present invention is applicable to containers other than circular or cylindrical. Attached to the end wall panel 17 by an integral rivet 20 is a tab generally indicated at 22.

The tab 22 is preferably of the longitudinally rigid type, and includes a nose portion 23 and a lifting portion 24. The lifting portion 24 of the tab is provided with a finger hole 26 to enable the user to grasp the tab for the pulling operation normally required after the principal score line has been initially ruptured. As indicated, the tab 22 includes a tail portion 27 in the form of flat sheet stock integral with the remaining portion of the tab. The tail provided with an aperture, as shown, which receives the rivet 20 normally integrally formed from the end panel 17.

In the form illustrated in FIGS. l-3, the end structure 12 includes a protective guard 30 in the form of multiple folds of the material constituting the end wall of the end structure, the protective guard being operative to protect the user against laceration of the free edge of the score line formed when the end panel 17 is removed. It will be apparent to those skilled in the art that other forms of protective guards may be used, for example, a guard of the type described in US. application Ser. No. 236,654 previously identified. Whatever the precise form of the protective guard 30, it normally extends completely around and adjacent to the principal score line 15.

As illustrated in FIG. I, a secondary score line 31 is located in the end structure and cooperates with the tab and the principal score line to affect a bending action and functions as a fold line during the operation of the end structure in an opening sequence. It will be understood that secondary score lines of different configurations may be used, and in addition to functioning as a bend line or hinge, the secondary score line may also perform a venting function and cooperate to permit movement of the tab nose radially outwardly towards the principal score line.

In the normal use of the end structure illustrated in FIG. I, it is intended that the user insert a finger between the end panel 17 and the lifting end 24 of the tab to raise the free end 24 of the tab to a position of approximately 30 with respect to the plane of the end wall 17. In so doing, the nose end 23 of the tab, whose normal position is indicated in the dotted line in FIG. 2, is rotated downwardly into engagement with the score line to effect initial rupture of the score line and start the folding action along bend line 31. At this relative position of the tab, the free end or lifting end 24 is approximately between and 35 above the end wall 17, and the user has the option of continuing to rotate the tab towards the vertical position or inserting the finger through the finger hole 26 in the direction indicated by the arrow of FIG. 2. With the tab thus grasped by user, and with the score line 15 initially ruptured, pulling on the free end of the tab now results in severance of the remaining portion of the principal score line and removal of the full panel 17.

It will be apparent, that during the rotation of the tab from the horizontal towards the vertical position, the secondary score line 31 acts as a hinge permitting the nose of the tab to urge a portion of the end panel 17 into the container as the principal score line is ruptured locally in the area adjacent to and extending arcuately from the nose end of the tab.

The above operation is the normal sequence of opening of the usual type of full panel end structure. However, there have been instances in which the user has inserted his finger through the top of the finger hole rather than lifting the free end of the tab. When this is done, rather than attempt to continue to lift the free end of the tab such that the nose of the tab is urged into contact with the principal score line, the user attempts to pull the tab radially inwardly towards the center of the container, as indicated by the arrows in FIG. 2. Normally such pulling also involves a vertically upward component of force. Since this is not effective in rupturing the score line, the user continues to apply even greater radially inward force resulting in flexing of the end wall in the areas indicated by the arrows labeled F."ln other words, the portion of the end panel 17 immediately adjacent to the rivet, and the portion disposed on each side of the rivet tends to bulge upwardly somewhat with the result that the nose end of the tab is moved radially inwardly to the relative position indicated in FIG. 2 in the solid line.

As will be apparent, with the nose of the tab radially inwardly of the score line, it is out of operative position with respect to the score line fracturing sequence.

If the user continues to pull radially inwardly and lift upwardly, the tab assumes a position generally indicated in FIG. 3. in so moving the tab by the application of substantial pulling forces, the effect is to position the nose 23 of the tab even further inwardly radially with respect to the score line 15. Where a protective guard 30 is present in the end structure, the nose of the tab engages the protective guard, and continued upward movement is not only ineffective in rupturing the score line, but stresses the rivet significantly. In some instances, the stress on the rivet can be so substantial as to shear the rivet, or to cause the nose end of the tab to be folded under such that is now lies between the end wall with the free end or lifting end 24 of the tab being positioned radially outwardly of the center of the container in a position roughly l00 to with respect to the plane of the end wall 17. At this juncture, the container has not been opened and there has been a failure to rupture the score line with the result that the user becomes rapidly disenchanted with the container, and sometimes with the product packaged in the container because of the difficulty of opening the same.

As was pointed out previously, analysis of the failure mode of operation of the end structure, particularly end structures of the full panel pull out type, has indicated that the principal source of the problem and the structure involved which gives rise to the problem is the flexing which takes place in that portion of the end wall 17 immediately beneath the tab 22. Particularly involved is that portion of the end wall within the confines of the

tab side walls

32 and 33 and located adjacent to the rivet, especially that area which lies between the tail 27 and the side walls of the tab 22. The areas in question are designated in FIG. 1 as

areas

35 and 36, although it is to be understood that the area is generally arcuate in nature because it has been determined that this portion of the end wall is being flexed upwardly by the stresses applied to the end wall from the tab, through the rivet and to the end wall. Accordingly, the present invention is directed specifically to structres which incorporate reinforcing and strengthening means in that portion of the end wall 17 which is flexed as a result of attempted improper operation of the tab.

Referring to FIGS. 4-6, the improved end structure 40 of the present invention is illustrated, such structure including strengthening means generally indicated 42. In the form illustrated in FIGS. 4-6 wherein like reference numerals have been used where applicable, the strengthening means 42 are located in the end wall 17,

and particularly that portion of the end wall immediately beneath the tab 22. In this exemplary embodiment, the strengthening means includes a pair of angularly disposed depressions. 44 and 45. which form spaced legs each of which is positioned on one side of the rivet 20.

The

deformations

44 and 45 operate to prevent flcxing of that portion of the end wall 17 in the area of the rivet 20 and that portion of the end wall radially inwardly of the rivet. As shown. the tab tall 27 may be notched to receive a small bubble in the end wall in order to prevent rotation of the tab.

One advantage of the use of deformations 44. 45, as illustrated, is the fact that presently existing tooling for the production of end units may be relatively easily modified to include the necessary die and anvil configurations to produce

depressions

44 and 45 in the areas indicated.

The

depressions

44 and 45 effectively act as strengthening and reinforcing means in that the depressions function as longitudinally rigid levers while at the same time taking up any excess metal which is in the area of the rivet. the excess metal tending to promote undesirable flexing of that portion of the end wall during an improper opening Sequence.

In operation, even if a user were to insert his finger beneath the lifting end 24 of the tab to raise the same partially but short of a position at which rupture of the score line is effected. and assuming that the user thereafter inserts his finger through the finger hole 26 and attempts to pull the tab radially inwardly and upwardly. the

deformations

44 and 45 act as reinforcing means to prevent flexing of that portion of the end wall immediately surrounding the rivet thereby preventing the nose 23 of the tab from being moved radially inwardly away from the principal score line 15. Thus. even though the user continues to attempt to pull the tab radially inwardly. the same pulling action tends to raise the lifting end of the tab further. but the stiffening means prevents movement of the nose of the tab away from the score line. and thus. assure that the nose of the tab remains in operative relationship with respect to the principal score line. Also. since the nose of the tab is not moved radially inwardly. the proper relationship exists between the secondary score line 31, the principal score line and the tab nose such that continued lifting of the free end ofthe tab 24 results in initial rupture of the principal score line and the start of the folding or hinging action. Once this has occurred, even though the tab is not lifted to the complete vertical position. the score line 15 has been fractured sufficiently to permit removal of the entire end wall 17.

In most instances. the reinforcing means illustrated in FIGS. 4-6 operates successfully to prevent an attempted improper operation of the tab in an opening sequence. Yet. it is possible under a very specific set of circumstances to achieve a failure mode. For example, if a user inserts his finger into the finger hole. and without lifting the end 24 of the tab. pulls radially on the tab towards the center of the panel 17, and if sufficient force is applied it is possible to move the nose of the tab radially inwardly a small amount. While this does not necessarily result in a failure mode. even with the structure as illustrated in FIGS. 4-6, the opening sequence is not as smooth as the design is intended to accomplish.

Accordingly. in another form of the present invention the end wall is provided with a structure which tends to prevent insertion of the finger through the finger hole of the tab until the lifting end 24 of the tab has been raised sufficiently to bring the nose end of the tab into operative fracturing relationship with the principal score line.

Referring to FIGS. 7-9 in which like reference numerals have been used where applicable, a variant form of the present invention is illustrated which not only provides strengthening means in the area surrounding the rivet, but which also includes means tending to inhibit and to prevent the user from inserting his finger into the finger hole for the purpose of pulling the tab radially inwardly without lifting the free end 24 of the tab.

The end structure 50 illustrated in FIGS. 7-9 includes strengthening means generally indicated 52 in the form of an arcuate raised section 55. the latter being provided with spaced legs 56 and 57 positioned on each side of the rivet 20 and closely adjacent to the tail 27 of the tab 22. The arcuate raised section 55 is another form of deformation of the end wall 17 in the area thereof which tends to flex. and effectively accomplishes the same purpose as the strengthening means 42 previously described. The particular form illustrated in FIGS. 7-9 also offers the advantage of being easily pro vided in presently existing tooling. since the deformation is in the end wall and the tooling may be modified relatively easily to provide the strengthening means in the proper position in the end structure.

The end structure 50 illustrated in FIGS. 7-9 also includes a second arcuate raised deformation 60 spaced radially inwardly from the arcuate raised section 55, and so located in the end panel I7 as to be positioned closely adjacent to that portion 62 of the tab 22 on which the user would normally place his finger if he were to attempt to pull the tab radially inwardly towards the center of the container. In effect. arcuate section 60 functions as an anti-pull structure which prevents the users finger from coming in contact with that portion 62 of the tab normally engaged by the finger in an attempt to pull the tab radially inwardly. Effectively. the anti-pull structure virtually compels the user to lift the free end 24 sufficiently to clear the raised face 64 of arcuate section 60, and thus the anti-pull structure assures that the lifting end of the tab is raised sufficiently to bring the nose 23 of the tab into operative fracturing engagement with the score line 15. This is accomplished by proportioning and dimensioning the anti-pull section 60 such that the user cannot insert his finger into the finger hole 26 of the tab until the free end has been raised sufficiently to clear the raised face 64. and sufficiently cleared to enable the user to insert his finger in between the raised face and the angularly disposed lifting end 24 of the tab. However. in this relative position of the tab. the nose has already fractured the score line and if the user attempts to pull the tab radially inwardly without any lifting component. the panel may be removed since the score line has already initially been ruptured.

In the alternative. the lifting end 24 of the tab can be moved closer to a full vertical position followed by the normal desired pulling action to remove the entire panel 17.

Another illustrative embodiment of the present invention is shown in FIGS. l0-l2 wherein like reference numerals have been used where applicable. End structure 70 is provided with a deformation generally indicated 75 and located in the end wall 17 in the area immediately adjacent to the rivet 20 and positioned within that portion of the end wall which lies immediately beneath the finger hole 26 of the tab 22. In the form illustrated, deformation 75 is generally arcuate and includes

leg portions

76 and 77 positioned immediately adjacent to the rivet, as illustrated. In the form shown, deformation 75 is generally circular in shape. and extends for approximately 300, the circle being interrrupted by that portion of the tab forming the tail 27.

Deformation 75 includes an upper flat surface 79, while the

leg portions

76 and 77 are positioned in that portion of the end structure which tends to flex during an improper opening operation. Thus, a portion of the deformation 75, and especially that portion thereof adjacent to the rivet-functions as a stiffening reinforcing means similar to deformation 55, and deformation 42, previously described.

In this particular form, the anti-pull feature has been combined with the reinforcing feature by configuring the deformation to be arcuate, while locating the deformation in that area of the end wall which tends to deform. As already described, that portion 81 of the deformation which is adjacent to surface portion 62 of the tab functions to prevent the user from inserting his finger through the finger hole 26 of the tab in order to grasp the tab along surface 62 in an attemptto pull the tab radially outwardly. Thus, by the structure shown and described, the user is virtually compelled to lift the free end 24 of the tab, which causes the nose 23 thereof to come into operative fracturing engagement with the principal score line 15. Once the free ends of the tab has been lifted sufficiently for the underside of the tab to clear flat surface 79 of deformation 75, it is possible for the user to insert his finger through the finger opening for the purpose of pulling the tab radially inwardly away from the score line. However, in order for this to be done conveniently, the free end of the tab 24 must be lifted sufficiently. between 20 and 30 from the horizontal, at which point the nose end 23 of the tab has already initiated fracture of the principal score line. Once the score line has been fractured, pulling of the tab radially inwardly away from the score line permits removal of the entire panel 17. Alternatively, and a more preferred manner of operation involves continuing to raise the tab to approximately the 60 position or greater thus achieving the hinging action already described. Thereafter, the tab may be pulled upwardly and inwardly in order to effect removal of the entire panel 17.

Accordingly, it will be apparent to those skilled in the art and from the foregoing description that a substantially improved end structure has been provided for convenience-type containers, especially those of the full panel pull out variety. By the present invention. an end structure is provided such that an attempted operation which would normally likely result in a failure of the end structure to open properly is effectively prevented.

As indicated earlier, one of the advantages of the present invention is the effectiveness by which failure modes are substantilly eliminated by use of strengthening and reinforcing means in that portion of the end wall tending to flex. Moreover, one of the advantages of the present invention is the fact that presently existing tooling may be modified to provide the reinforcing means in the designated areas of the end wall.

lt will be apparent to those skilled in the art, from the foregoing illustration and description of the various forms of the invention, that modifications may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention as defined in the following claims.

I claim:

I. An easy opening end for containers comprising:

an end wall including a score line defining an opening in said end wall in response to rupture of at least a portion thereof;

tab means and means to affix said tab means to an end wall;

said end wall including protective guard means cooperating with said score line;

said tab including a nose and a lifting end and being so oriented that said nose is adjacent the score line and the lifting end extends towards the center of said end wall;

said tab being operative in normal operation to initiate rupture of said score line in response to movement of said lifting end away from said end wall, and

means in said end wall and operative as the end of said tab is lifted at the start of an opening sequence to prevent upward flexing of the portion of said end wall underlying said tab and adjacent to said affixing means tending to allow radially inward movement of said tab nose out of operative rupturing position with said score line.

2. An easy opening end as set forth in claim 1 wherein said means to prevent flexing includes reinforcing means in said end wall.

3. An easy opening end as set forth in claim 1 wherein said means to prevent flexing includes deformations in said end wall is operative to stiffen the portion of said end wall adjacent to said afflxing means to prevent upward deformation thereof in response to movement of the lifting end of said tab.

4. An easy opening end as set forth in claim 2 wherein said reinforcing means includes a pair of spaced angularly disposed depressions.

5. An easy opening end as set forth in claim 2 wherein said reinforcing means includes deformation means in said end wall, and

said deformation including spaced leg portions positioned to prevent said flexing.

6. An easy opening end as set forth in claim I wherein said tab is a longitudinally rigid tab,

said tab being attached to said end wall by an integral rivet, and

said end wall including protective guard means radially outwardly of said nose.

7. An easy opening as set forth in claim 1 wherein said end wall includes means forming a hinge for downward movement of a portion of said end wall in response to movement of said lifting end of said tab.

8. An easy opening end as set forth in claim 6 wherein said means to prevent flexing operates to prevent movement of said nose of said tab radially inwardly over said protective guard means.

9. An easy opening end as set forth in claim 8 wherein said means to prevent flexing includes reinforcing means in said end wall.

10. An easy opening end as set forth in claim 9 wherein said reinforcing means includes spaced leg portions positioned adjacent to said rivet means.

11. An easy opening end as set forth in claim 9 wherein said reinforcing means is an arcuate raised portion in said end wall.

12. An easy opening end as set forth in claim 9 wherein said reinforcing means includes a pair of spaced angularly disposed depressions. and

one of said pair being disposed on each side of said rivet and spaced therefrom.

13. An easy opening end as set forth in claim 9 wherein said lifting tab includes means forming a finger hole, and

wherein said reinforcing means is so positioned with respect to the lifting end of the tab as to prevent grasping of the lifting end of the tab by inserting of a finger through said finger hole until the lifting end of the tab has been raised to initiate rupture of said score line.

M. An easy opening end as set forth in claim 9 further including means cooperating with said lifting end of said tab to prevent pulling the same radially outwardly of said score line until the lifting end has been raised sufficiently to initiate rupture of said score line.

15. An easy opening end for containers comprising:

an end wall;

tab means to attach said tab to said end wall;

rupturable means in said end wall for removing substantially the entire end wall;

said tab including a nose end adjacent to said rupturable means and a lifting end positioned radially inwardly thereof, and

means in said end wall cooperating with said tab to prevent radially outward movement of the nose of said tab relative to said rupturable means in response to attempted movement of the lifting end of said tab upwardly and radially outwardly of said rupturable means.

16. An easy opening end as set forth in claim 15 wherein said end wall includes a protective guard means having a portion thereof vertically displaced with respect to the plane of the end wall, and

said means to prevent radially outward movement being operative to prevent the nose of said tab from being moved radially inwardly into engagement with said portion of said protective guard means.

17. An easy opening end as set forth in claim 15 wherein said means in said end wall includes reinforcing means to prevent flexing of the portion of said end wall underlying said tab and adjacent to said affixing means.

18. An easy opening end as set forth in claim 17 wherein said reinforcing means includes a pair of spaced angularly disposed depressions.

l9. An easy opening end as set forth in claim 17 wherein said reinforcing means includes means forming a deformation in said end walL said deformation including spaced leg portions positioned to prevent said flexing.

20. An easy opening end as set forth in claim 19 wherein said reinforcing means is an arcuate raised portion in said end wall.

21. An easy opening end as set forth in claim l7 wherein said lifting tab includes means forming a finger hole, and

wherein said reinforcing means is so positioned with respect to the lifting end of the tab as to prevent grasping of the lifting end of the tab by insertion of a finger through said finger hole until the lifting end of the tab has been raised to initiate rupture of said score line.

Claims

1. An easy opening end for containers comprising: an end wall including a score line defining an opening in said end wall in rsponse to rupture of at least a portion thereof; tab means and means to affix said tab means to an end wall; said end wall including protective guard means cooperating with said score line; said tab including a nose and a lifting end and being so oriented that said nose is adjacent the score line and the lifting end extends towards the center of said end wall; said tab being operative in normal operation to initiate rupture of said score line in response to movement of said lifting end away from said end wall, and means in said end wall and operative as the end of said tab is lifted at the start of an opening sequence to prevent upward flexing of the portion of said end wall underlying said tab and adjacent to said affixing means tending to allow radially inward movement of said tab nose out of operative rupturing position with said score line.

3. An easy opening end as set forth in claim 1 wherein said means to prevent flexing includes deformations in said end wall is operative to stiffen the portion of said end wall adjacent to said affixing means to prevent upward deformation thereof in response to movement of the lifting end of said tab.

5. An easy opening end as set forth in claim 2 wherein said reinforcing means includes deformation means in said end wall, and said deformation including spaced leg portions positioned to prevent said flexing.

6. An easy opening end as set forth in claim 1 wherein said tab is a longitudinally rigid tab, said tab being attached to said end wall by an integral rivet, and said end wall including protective guard means radially outwardly of said nose.

12. An easy opening end as set forth in claim 9 wherein said reinforcing means includes a pair of spaced angularly disposed depressions, and one of said pair being disposed on each side of said rivet and spaced therefrom.

13. An easy opening end as set forth in claim 9 wherein said lifting tab includes means forming a finger hole, and wherein said reinforcing means is so positioned with respect to the lifting end of the tab as to prevent grasping of the lifting end of the tab by inserting of a finger through said finger hole until the lifting end of the tab has been raised to initiate rupture of said score line.

14. An easy opening end as set forth in claim 9 further including means cooperating with said lifting end of said tab to prevent pulling the same radially outwardly of said score line until the lifting end has been raised sufficiently to initiate rupture of said score line.

15. An easy opening end for containers comprising: an end wall; tab means to attach said tab to said end wall; rupturable means in said end wall for removing substantially the entire end wall; said tab including a nose end adjacent to said rupturable means and a lifting end positioned radially inwardly thereof, and means in said end wall cooperating with said tab to prevent radially outward movement of the nose of said tab relative to said rupturable means in response to attempted movement of the lifting end of said tab upwardly and radially outwardly of said rupturable means.

16. An easy opening end as set forth in claim 15 wherein said end wall includes a protective guard means having a portion thereof vertically displaced with respect to the plane of the end wall, and said means to prevent radially outward movement being operative to prevent the nose of said tab from being moved radially inwardly into engagement with said portion of said protective guard means.

19. An easy opening end as set forth in claim 17 wherein said reinforcing means includes means forming a deformation in said end wall, said deformation including spaced leg portions positioned to prevent said flexing.

21. An easy opening end as set forth in claim 17 wherein said lifting tab includes means forming a finger hole, and wherein said reinforcing means is so positioned with respect to the lifting end of the tab as to prevent grasping of the lifting end of the tab by insertion of a finger through said finger hole until the lifting end of the tab has been raised to initiate rupture of said score line.