EP0460200A4

EP0460200A4 - Easy-access sheet metal container structures

Info

Publication number: EP0460200A4
Application number: EP19910902933
Authority: EP
Inventors: William T. Saunders
Original assignee: Weirton Steel Corp
Current assignee: Weirton Steel Corp
Priority date: 1989-12-21
Filing date: 1990-12-20
Publication date: 1993-12-15
Also published as: JPH05500199A; WO1991009784A1; EP0460200A1

Abstract

Scoreline, profiling and reinforcing features are provided for an easy-access sheet metal end closure (20) and an integral opener (44). An endwall panel (28) is formed so as to substantially eliminate flexing of the sheet metal during opening of residual metal of scoreline means defining a U-shaped tear strip (30). Such tear strip is oriented with its arcuately-shaped closed end (32) contiguous to the periphery of such endwall panel with scoreline legs (34, 35) directed toward a portion at its geometric center (26). The opener is fabricated with a chisel-point (92) at its working end (66) to initiate rupture of such arcuate-shaped scoreline by Class 1 lever action; followed by pivoting of the opener about fulcrum points (82, 83) with one each contacting the panel on each side of opening (62) for rupturing such scoreline legs by Class 2 lever action. The opener and tear strip are retained and stored externally on the panel without obstructing the opening (62).

Description

EASY-ACCESS SHEET METAL CONTAINER STRUCTURES

This invention relates to easy-access sheet metal container structures, their fabrication and usage. In its more specific aspects, this invention is concerned with scoreline, profiling and reinforcing features, for container wall panel and integral opener structures, which facilitate both fabrication and functioning of such structures for purposes of severing scored sheet metal and movement of a resultant tear strip from such wall panel to form an opening for a container while retaining and storing such tear strip and opener externally of the container without obstructing such opening.

Prior art convenience-feature end closure structures for beverage cans, include:

1) the early-developed ring-pull throw-away type in which a scored portion, near the geometric center of a sheet metal endwall panel, was initially ruptured by Class 2 lever action and, then, was pulled in an external direction to separate the scored sheet metal and ring-pull handle entirely from the panel, 2) a "tape sealed" type in which metal foil laminated with adhesive covers a small pour opening in a sheet metal endwall of a can for non-carbonated beverages, such as tomato juice; and

3) a "retained tab" type for forming an opening by rupturing sheet metal near the geometric center of an endwall panel and pushing such ruptured sheet metal into the interior of the container using an integral opener which is retained on the panel adjacent to the opening; the latter type is currently the standard for commercial use on carbonated beverage cans.'

Applicant's U.S. Patent #4,576,305 initiated a differing approach for attaining "retained-tab" features on an easy-open end closure. The present retained-tab end closure structures provide new configurations and dispositions for (a) sheet metal scorelines (b) tear strip profiling, (c) sheet metal shaping and (d) integral sheet metal opener structure; each of which contributes to achieving new results which facilitate fabrication and functioning of such structures to provide better sanitary and tamper-resistant conditions for canned comestibles; and, better environmental conditions enabling retention of both sheet metal tear strip and opener in an overlaying stored relationship which is not only out of contact with container contents by being located on the exterior of the container but, also, out of the way for pouring from or drinking from the container. Such advantages and contributions are considered in more detail in describing structures shown in the accompanying drawings; in such drawings:

FIG. 1 is a top plan view of an endwall panel embodiment omitting an opener for better illustrating tear strip scoreline and profiling features of the invention;

FIG. 2 is a bottom plan view of the embodiment of

FIG. 1 subsequent to forming a unitary rivet button for securing an integral opener to the tear strip;

FIG. 3 is a top plan view of the embodiment of FIG. 2 with the new opener of the invention secured in place by a unitary rivet;

FIG. 4 is a top plan view, after opening, of the embodiment of FIG. 3;

FIG. 5 is a bottom plan view of the embodiment of FIG. 4;

FIG. 6 is a top plan view of the new opener structure of the invention; FIG. 7 is an enlarged front elevational view showing the "gull-wing" working end of the new opener of the invention;

FIG. 8 is a partial side elevation view, partially in section, of such gull-wing portion of the opener shown in FIG. 7;

FIG. 9 is a cross-sectional view of the embodiment of FIG. 3 taken along the line 9-9 of FIG. 3; FIG. 10 is an enlarged cross-sectional schematic of a portion of the endwall cross section of FIG. 9;

FIG. 11 is an enlarged schematic view of perspective wall and opener portions describing the initial lever-action rupture of the nose portion of an elongated tear strip for opening a container in accordance with the invention;

FIG. 12 is an enlarged perspective view for describing a sequential lever action opening stage subsequent to that of FIG. 11; and

FIG. 13 is an enlarged perspective view for describing an opening stage subsequent to that of FIG. 12;

FIG. 14 is a cross-sectional view for showing storage of the tear strip and integral opener on the exterior surface of an endwall closure structure embodiment of the invention, and FIG. 15 is a top plan view of an elongated unitary sheet metal strip showing the progression of sequential fabricating stages for the new opener of the invention.

Referring to the container endwall embodiment of FIG. 1, the opener and means for securing an opener to a panel are omitted in order to better show the inter¬ relationships of the new scoreline and tear strip profiling features taught by the invention. Endwall closure 20 includes peripheral chime seam metal 21, chuck wall 22, a countersink indentation 24 and protruding bead 25; all of which are symmetrically disposed in relation to the geometric center 26 of wall panel 28; and, each can be fabricated as part of a shell forming stage for an end closure.

During fabrication, a pair of panel protrusions, one of which is designated as 29, provide for accurate registration as the sheet metal work product is moved from station to station during fabrication of easy-access features.

After such shell forming stage, the sheet metal of panel 28 (which has a preselected nominal thickness) is scored to provide residual metal of predetermined, decreased thickness(es) . Such scoring defines a tear strip 30 which is .--to be moved from the substantially planar contour of such wall panel by severing such residual metal. Profiling of the tear strip 30 is carried out contemporaneously with such scoring and functions to take up excess metal generated by such scoring.

In providing a pour opening for a beverage can as shown in FIGS. 1-5, an elongated U-shaped tear strip 30 is defined by scoreline means which include curvilinear scoreline 32 (which is arcuate-shaped in plan view) and a pair of elongated scoreline legs 34,35.

In defining the tear strip, a scoreline leg extends from each side of the arcuate-shaped scoreline 32, in parallel or slightly converging relationship to central longitudinal axis 36, to provide a narrow-width elongated tear strip 30. Its lateral sides extend from such curvilinear closed end (defined by arcuate-shaped scoreline 32) toward the remaining (open) end 38 of the U- shaped configuration. The closed end 32 is contiguous to the periphery of the endwall panel and the open end 38 is contiguous to the geometric center of the illustrated panel.

The scoreline legs 34,35 are symmetrically disposed in relation to central longitudinal axis 36; are preferably linear and converge slightly in extending from the arcuate-shaped scoreline 32. Scoreline legs 34,35 can be parallel but, any substantial divergence is avoided in accordance with present teachings. In the embodiment shown in FIGS. 1,2 the angle of convergence of each leg is about 1" 15" (with a practical combined maximum convergence of about 3" considering convergence of both legs) . The scoreline legs are rectilinear for fabricating purposes, and for tooling preparation purposes; but, slight curvilinearity in configuration could be tolerated if the above-described, narrow-width, symmetrical characteristics for the tear strip which precludes slippage of the tear strip or opener into the container, and the desired characteristics for the opening, are maintained; also, the lever action and other features, described later, which comprise novel concepts and teachings of the invention must be maintained.

The distal ends of elongated scoreline legs 34, 35 terminate at, and define, such remaining (open) end 38 of the U-shaped configuration; so that, tear strip 30, while being movable from the original contour of the wall panel 28, remains unitary with the remainder of such wall panel by means of the sheet metal at open end 38. A panel portion 40, located beneath handle end 42 of a tab opener 44 (as seen in FIG. 3) , facilitates prying access for initiating lifting of handle end 42 in a direction away from the external surface of panel 28. Shallow-depth profiling ribs 46,47 and 50,51 (FIG. 2) in the defined tear strip 30 serve plural functions in addition to absorbing excess metal generating during scoring. Preferably, the profiling ribs are parallel to the scoreline legs as shown by FIGS. 1,2. Such profiling is strategically placed longitudinally within the scored periphery of tear strip 30 to help establish separate longitudinal segments of the tear strip which help to achieve desired action during the opening procedure and, also, a desired folding action for storing such longitudinal sections of tear strip 30 and opener 44 (within the confines of the chuck wall 22, FIG. 4). The length and disposition of the tear strip, placement of the rivet, and length of the opener are coordinated as taught herein for such interfitting storage purposes.

Tear strip profiling ribs 46,47 and 50, 51 (FIGS. 1-5) extend longitudinally in a preselected manner. They are positioned to provide a segment 54 of the tear strip, which is transverse to the central longitudinal axis (36) and longitudinally intermediate rib pairs 46,47 and 50,51, respectively. The transverse section 54 is free of longitudinally-extending profiling and allows for placement of a rivet button as shown in FIG. 2 (as well as the rivet head on the exterior) ; and, in addition, such spacing provides for folding of the longitudinally distinct segments of the tear strip. Two such folding segments are formed; the lead segment includes nose portion 55 and transverse section 54 (which includes the rivet) ; and, the trailing segment 56 comprises the remaining portion of the tear strip extending to the open end of the U-shape at 38. Ribs 46,47 are in the lead fold segment (extending into the semi-circle defined by scoreline 32) ; ribs 50,51 are in the second trailing fold

segment extending to the vicinity of the distal ends of scoreline legs 34,35.

These distinct segments of tear strip 30 are folded in relation to each other during opening and

5 storage. Results of such coordinated actions, including compact interfitting relationships, are illustrated in plan view by FIG. 4.

Individual profiling ribs 46,50 are contiguous to, and parallel to, scoreline leg 34 within the periphery

10 of tear strip 30; and, individual ribs 47, 51 are contiguous to, and parallel to, scoreline leg 35 within, the periphery of tear strip 30. Preferably, longitudinally extending rib means do not extend beyond the distal ends of scoreline legs. That is, ribs 50,51 preferably

15 terminate at open end 38 and facilitate folding of the sheet metal at such terminating ends of the scoreline legs 34,35.

Transverse section 54 (FIG. 2) of the tear strip 30 is free of longitudinally-directed ribs and surrounds

20 the unitary rivet button 60. The nose section 55 (circumscribed at least in part by scoreline 32) and the transverse section 54, taken together comprise a first tear strip segment; a second tear strip segment is started at the start of ribs 50,51 which extend toward the

25 remaining end of the tear strip.

The segment which includes nose section 55 and transverse section 54 is folded in angled relationship to the second fold segment 56 during opening procedure; and, overlays such remaining segment 56 as tear strip 30 is

30 stored (FIG. 4) . Opener 44 overlays both folded segments and a panel portion leading to chuck wall 22; neither the retained tear strip nor opener obstruct, in any way, pour opening 62 (as seen from both FIGS. 4 and 5) . Opener 44 is held integrally with the sheet metal of tear strip 30 by unitary rivet head 64 (FIG.3). Working (output) end 66 of opener 44 is in place contiguous to arcuate-shaped scoreline 32; and, handle (input) end 42 overlays recessed panel portion 40 prior to opening.

After opening, such handle end 42 abuts the chuck wall 22 of the end closure (FIG. 4); that is, in the circular embodiment illustrated, such folded disposition of handle 42 is diametrically opposite to that portion of panel 28 at which rupture of the tear strip 30 is initiated.

Referring to the plan view of FIG. 6, sheet metal opener 44 provides a means for gripping at its handle end, such as 68 which can be a ring-pull opening as shown, or a solid panel. A rivet button aperture 69 is in recessed opener panel 70. Strength can be augmented by ribs 71,72; but, the overall longitudinal and lateral strength of the illustrated opener is, in addition to thickness gage considerations, greatly supplemented by edge curling of the sheet metal; sheet metal gage for flat rolled steel can generally be in the range of about 100 to 150 #/bb when edge curling is used. Such edge curling (which tucks the raw edge metal within the curl) extends along lateral sides 75,76, and handle end 42. In a ring-pull model, the internal periphery (78) edge metal of ring-pull opening 68 is also curled.

Curled edge metal along the lateral sides is illustrated at 80 and 82 of FIG. 7. The sheet metal curl terminates contiguous to working end 66 of opener 44 where a "gull-wing" configuration is symmetrical about vertical centerline 84. Each such gull-wing 88,90 extends from chisel point edge 92 toward lateral side curled edge metal 80, 81, respectively; such gull-wings terminate at pivot- points (curl termination points) 82,83, respectively.

Such chisel-point and gull-wing configurations are formed subsequent to curling edge metal around substantially the remaining periphery of the opener 44. Movement of metal at such curl-free end 66 to a level below that of the edge curls 80, 81 (i.e. forming the gull-wing) is carried out by draw tooling to form the centered slot 96 (FIGS. 3,6 and 7) which extends between recessed opener panel 70 and the chisel-point 92 located where the central longitudinal axis intersects working end 66.

Such relative levels, and other novel features of the "gull-wing" working end 66 for opener 44 are further shown by the partial view of FIG. 8; the level of the recessed opener portion 70 is indicated at 98; the gull- wing upper level is indicated at 100; and, the lower level of the "knife-edge" chisel-point 92 is indicated at 102. For initiating rupture purposes, chisel-point 92 is disposed toward the panel contiguous to the mid-point of scoreline 32.

Referring to the cross-sectional view of FIG. 9, chime seam metal 21, at the outer periphery of the end closure 20, leads into vertically-oriented chuck wall 22 which extends around the full periphery of a circular (or other configurations such as rectangular or oval) panel. Chuck wall 22 extends into countersink indentation 24 which provides buckle resistance when the panel is subjected to internal pressure. An important concept of the present invention is the importance of avoiding flexing of, or play in, the sheet metal panel as lever-action initial puncture and scoreline rupture are taking place. It has been found that flexing, that is "play" or "give" in the sheet metal, has a tendency to put scoreline residual sheet metal under tension for purposes of rupturing. Breaking such metal against its tensile strength is one of the most difficult ways to rupture sheet metal because of inherent tensile strength characteristics of the primary metals used in can manufacture.

In a preferred embodiment, this concept of preventing such flexing of the sheet metal endwall panel is achieved by locating externally projecting bead 25 inboard of and contiguous to countersink indentation 24; force requirements for initial puncture and rupturing are decreased as much as 30% by this feature - which is a significant factor in opening ends for small diameter containers.

Projecting bead 25 changes how the sheet metal of panel 28 is presented for opening and how such sheet metal reacts to puncturing and/or rupturing under lever action and/or severing by a tearing action. Placement of projecting bead 25 makes the endwall sheet metal more rigid; flexing of the sheet metal, contiguous to tear strip scoring is substantially eliminated. The prior "give" or "play" in sheet metal panels without such means, which increased the need to "break" the residual metal under tension, is substantially eliminated.

Such rigid presentation of the sheet metal provides rapid lever-action rupture - first by puncturing at the mid-point of scoreline 32, with rivet 64 acting as the fulcrum and continuing to severe along such arcuate portion of scoreline 32. Such class 1 lever action occurs with a resonating sound because of the rigidity of the metal. The arcuate movement (due to lifting) of the handle end inherently continues so that the class 1 lever action promptly becomes a class 2 lever tearing action (along scorelines 34,35) as the pivot point contacts 82,83 become the fulcrum; such point contacts 82,83 constitute a moving fulcrum; they move along the edges of opening 62 as indicated by lines 104,106 of FIGS. 4,5. Such class 2 lever action severance of the scoreline legs occurs in a rapid smooth transition at or about completion of class 1 lever-action rupture of arcuate-shaped scoreline 32 which occurs at about 25" of arcuate movement of the handle end 42 of opener 44; the class 2 severance of scoreline legs 34,35 is completed at an angular movement of about 75^"* approaching vertical (perpendicular to the plane of panel 82) orientation for opener 44.

Because of the rigid characteristics of the sheet metal resulting from impression of projecting bead 25, both such lever actions occur rapidly with resonating sounds from the rigid metal. Opener 44 is about 15^"" from a vertically upright position as scoreline leg tearing is completed. Handle end 42 of opener 44 is then merely pushed or pulled backwardly in the direction of its original position. Both fold lines - for the lead segment (across transverse section 54) and for the trailing segment (across the terminal ends of the scoreline at 38) were started during the opening procedure so that both folded segments of the tear strip move readily into an overlaying relationship as they are stored, with the opener 44, in parallel relationship to panel 28. Relative positioning before opening (FIGS. 9 and 10) followed by the actions of FIG. 11-13 leads to final stored positioning (FIGS. 4,14).

As shown in the enlarged schematic cross- sectional view of FIG. 10, chuck wall 22 extends into countersink indentation 24. Externally projecting bead 25 extends above the level of panel 28 as indicated; scoreline residual metal 110 is at the mid-point of arcuate-shaped scoreline 32. The chisel-point 92 is located above such mid-point; gull-wings, as earlier described, lead to the main level of the opener 44 which extends along its sides from pivot points 82,83.

Referring to perspective views FIGS. 11-13 for further description of the leveraged opening, folding, and storing actions, in FIG. 11 the arcuate-shaped scoreline 32 is being ruptured by class 1 lever action of opener 44,^' moving about rivet 64 as a fulcrum, as a result of arcuate movement (through about 25^"") of handle end 42 externally away from panel 28. As arcuate movement of handle end 42 of opener

44 continues toward a vertically-upright position (included angle between opener 44 and panel 28 about 75"^* as shown in FIG. 12), scoreline legs 34,35 are ruptured by class 2 lever action as the pivot-point contacts 82,83 slide along the rigid panel adjacent to lateral sides of the pour opening 62.

With severing of scored metal of tear strip 30 being completed, and folding along tear strip fold lines being started during opening, opener 44 can be readily returned toward its original level. As such handle end 42 of opener 44 is returning toward panel 28, folding of the two longitudinal segments of the tear strip in overlaying relationship is completed. The opener 44 overlays such segments with each being substantially parallel to panel 28. Handle end 42 fits within the chuck wall 22 as shown in FIGS. 4 and 14. To achieve such an interfitting relationship, the length of the opener 44 is coordinated with the length of the tear strip 30, positions of the rivet 62 and rivet aperture 69, and the inter-folding relationship of the tear strip segments; along with other factors, such as shell forming dimensions in a circular end closure, which have to be coordinated to achieve a workable easy-access structure.

In a workable embodiment for a 202 (2-2/16" diameter) can body, having a necked-in 201 (2-1/16") open end, the following dimensions are typical:

ITEM DIAMETER- Chime metal (outer periphery) 2.310" Chuck wall 22 1.962" Center of countersink 24 1.868" Center of projecting rib 25 1.764"

ITEM RADIAL LENGTH

Tear strip .715" c/1 of rivet to opener end 66 .292"

Geometric center of panel 28 to opener working end 66 .830"

Geometric center of panel 28 to opener handle end 42 .270"

Longitudinal segment (section 54 and 55) at closed end of U-shape 355"

Longitudinal segment 56 at open end of U-shape 360'

Countersink indentation 24, radius 037"

Projecting bead 25, radius 007"

Scoreline 32, radius 156'

ITEM HEIGHT Chuck wall 22 to level of panel 28 1.65"

Chuck wall 22 to bottom of countersink indentation 24 2.12"

Tear strip profiling ribs - .007" Projecting rib 25 (above panel 28) .047"

Countersink indentation 24 (below panel 28) .037"

Typical flat rolled steel gages for such end closure are between about 75 and 110 lbs/bb with residual metal of the tear strip scoreline means being between about .001" and .0035". In a specific embodiment of the above example, .008" gage sheet metal was used; residual metal measured .0009" at scoreline 32, and residual metal was measured up to .0016" along scoreline legs 34,35; such specific embodiment for a 202 can body withstood nominal 100 psi internal pressure without leakage or bursting along such tear strip scorelines.

The preferred flat rolled steel substrate for end closures for containers for comestibles is electro- lytically treated on both substrate surfaces; for example application of a metallic coating, such as chrome oxide or chrome and chrome oxide, which acts as a surfactant to facilitate adhesion, on each such surface of an organic coating with lubricant (both of which must be approved by the FDA for use with products for human consumption) .

Typical flat rolled aluminum substrates are in the range of about .012" to about .015" with residual scoreline metal of about .004" to about .008"

Special features of sheet metal opener 44 are achieved by a progression of fabricating stages, numbered 111 through 118 which are carried out on an elongated sheet metal strip 119. Initially registration holes 121,123 are punched out of the strip using punch and die 15 tooling and opener panel 70 (shown in FIG. 6) is shaped by draw process tooling in first stage 111. In the progression illustrated, conventional punch and die operations can be used for punching out portions of the sheet metal; and, conventional draw processing operations can be used; of course, opposing tooling members of each are designed to provide the shaping taught by the invention.

The next sequential stage 112 comprises punching out opening 125 which is a preforming step in providing a ring pull. In stage 113 rivet button opening 69 (FIG. 6) is punched out of panel 70 followed by punch-out of a "bat-winged" configuration opening 126 in stage 114. Such angled "bat-wing" edges define working end 66 metal edge portions which will be formed into chisel-point 92 and gull-wings 88,90 (FIG. 7).

In stage 115, cut lines 127,129 for preforming lateral sides 75,76 of opener 44 are made; and, curvilinear cut line 131 is made for preforming of the handle end 42 of opener 44 (shown in FIG. 6) . The resulting partially precut work product for opener 44 of stage 115 remains part of strip 120 by means of unitary connector joints 133,135 (between small diameter punch holes) , which hold the work product through remaining stages for completion or near-completion (as selected) of opener 44 in a progression of stages while part of elongated strip 119.

Edge metal rolls 80,82 (FIG. 7) along lateral sides 75,76 are formed by progressively curling of edge metal in stages (116 and 117) . The edge metal is also curled for handle end 42; and curled metal extends around the internal periphery (78 in FIG. 6) in a ring-pull embodiment. Connector joints 133,135 (stage 117 and following stages) hold the work product for such progressive stages. Edge curling, in which raw edge metal is tucked on the inside of the curl, is known commercia1ly. Further shaping operations for the opener are carried out in 115 through 118 (while in strip form) in addition to edge curling. For example, draw process placement of the chisel-point is initiated in stage 116; and/or other steps such as forming four-pronged "rosette" 140 about opening 70 can be carried out in stage 118.

Placing an upward tilt at handle end 42; that is in a direction away from the external surface of an end closure can be carried out in strip form or subsequently; use of such handle tilt may be dependent on the type of finger access profiling provided for panel 28.

Draw processing of the working end 66 initiated in stage 116 must be completed in the progression or separately to form gull-wings 88,90 and position the chisel-point 92, as shown in FIGS. 7 and 8, to facilitate initial rupturing operations.

As seen in FIG. 7, knife-edge chisel-point 92 is located at the apex of gull-wings 88,90, at a level spaced (toward the panel and scoreline to be severed) from curled edge metal pivot points 82,83. Such placement along slope 96 (FIGS. 6,7) is completed using draw forming tooling.

Scale dimensions for an opener suitable for the above end closure embodiment for a 202 can body are approximated as follows:

Longitudinal length from working end 66 to handle end 42 1.10"

FROM KNIFE EDGE 92:

Longitudinally: to panel 70 .12" to center of opening 69 .26" to the inner curled ring pull opening 68 (inner edge 78) .55"

WIDTH: at pivot points 82,83 .35" at widest dimension for ring pull opening 68 .90"

SUBSTRATE:

Flat rolled steel, gage 110 to 155 #/bb

As pointed out earlier, the opener 44 can be pushed or pulled into stored position. For one-handed operation, opener 44 would maintain the solid panel (free of ring opening) presented in stage 111 of FIG. 15 by omitting the ring-pull punch out of stage 112. Specific materials, dimensions, and configurations have been set forth for purposes of describing a specific embodiment of the invention. However, in the light of such teachings, other sizes, configurations and/or dispositions can be devised while still relying on and utilizing concepts of the invention; therefore, for purposes of determining the scope of the present invention, reference shall be made to the appended claims.

Claims

1. An easy-access sheet metal wall panel with integral opener for severing a portion of such wall panel to provide an opening for a container, comprising a sheet metal wall panel, such wall panel having a nominal thickness gage and predetermined contour; scoreline means defining the scored periphery of an elongated U-shaped tear strip in such wall panel at which the sheet metal has been scored to decrease its. thickness in relation to such nominal thickness gage; such scored periphery being symmetrically disposed in relation to the central longitudinal axis of the elongated U-shaped tear strip; shallow-depth profiling extending longitudinally of such elongated tear strip within such tear strip scored periphery, such profiling being symmetrically disposed in relation to the central longitudinal axis of such tear strip; an elongated sheet metal opener for severing residual metal of such scoreline means to make such tear strip movable from the predetermined contour of such wall panel to provide an opening for a container, such elongated opener being symmetrically disposed in relation to its central longitudinal axis and having a working end and a handle end located at longitudinally opposite ends of such axis, and unitary rivet means securing such opener to such tear strip with the central longitudinal axis of such opener overlaying and having the same direction as the central longitudinal axis of such tear strip; such scoreline means including an arcuate-shaped scoreline defining a closed longitudinal end of such elongated tear strip and a pair of elongated scoreline legs extending toward the remaining longitudinal end of such tear strip, such central longitudinal axis of the elongated tear strip intersecting the arcuate-shaped scoreline at its midpoint, such scoreline legs extending from the arcuate-. shaped scoreline with one each of such legs on opposite lateral sides of such tear strip axis, such scoreline legs being spaced laterally from such tear strip axis with the major component of direction of each of such pair of scoreline legs being selected from the group consisting of substantially parallel to the central longitudinal axis of such tear strip and converging slightly toward such central longitudinal axis at an angle about 1-1/2^"* for each such leg in extending from the arcuate-shaped scoreline; the unitary rivet means joining sheet metal contiguous to the working end of such opener to the sheet metal the tear strip within the scored periphery, contiguous to such arcuate-shaped scoreline, such unitary rivet means being symmetrically disposed in relation to the central longitudinal axis of such opener and such tear strip in an area of such tear strip which is free o.f longitudinally-extending shallow depth profiling. 2. The structure of claim 1 in which such working end of the elongated opener includes an initial-contact edge for initiating rupture of such arcuate-shape scoreline; such initial-contact edge being positioned by such rivet contiguous to the mid-point of such arcuate- shaped scoreline to rupture such scoreline by Class 1 lever action, and in which arcuate movement of such handle end of such opener about such rivet as a fulcrum in an external direction in relation to such container on which such panel is used. 3. The structure of claim 2 in which such scoreline means is further severed after such Class 1 lever action initial rupture of the arcuate- shaped scoreline by. Class 2 lever action by continuing such arcuate movement of the handle end of such opener. 4. The structure of claim 1 in which such elongated opener is secured by such rivet means to sheet metal of the elongated tear strip such that its initial-contact edge is contiguous to and in overlaying relationship to a portion of such sheet-metal tear strip, which is circumscribed in part by such arcuate-shaped scoreline so as to cause such initial rupturing of such arcuate-shaped scoreline by Class 1 lever action upon movement of such opener handle end in an arc in a direction away from the external surface of such wall panel, with such unitary rivet means being positioned to initially act as a fulcrum for such Class 1 lever action. 5. The structure of claim 4 in which such elongated opener further includes a pair of pivot point contacts located in longitudinally recessed relationship to such initial- contact edge including one pivot point contact on each lateral side of such opener in laterally spaced relationship from the central longitudinal axis of such elongated opener; and such scoreline means is further severed, after such initial Class 1 lever action rupture, by pivoting such opener about such pivot point contacts, one each in contact with wall panel sheet metal on each lateral side of and externally of such tear strip, with such further severance along such scoreline legs being carried out by Class 2 lever action with such pivot point contact means acting as the fulcrum for such Class 2 lever action as movement of the handle end of the tab opener is continued in such arc direction externally of such container. 6. The structure of claim 5 in which rupturing of such scoreline legs is completed by such Class 2 lever action, and further including moving such handle end of such opener backwardly toward its original position. 7. The structure of claim 6 in which such shallow-depth profiling formed in the sheet metal of such tear strip provides longitudinally-extending ribs for reinforcing the original contour of separate longitudinally-extending segments of such tear strip, such profiling longitudinally-extending rib means extend with the major component of direction of such rib means being substantially the same as that of the scoreline legs of such a tear strip; such rib means being located along at least a portion of the elongated tear strip from contiguous to such arcuate-shaped scoreline toward such unitary rivet within a first longitudinal segment of such tear strip which includes such unitary rivet. 8. The structure of claim 7 in which such longitudinally extending rib means also include rib means located on the longitudinally opposite side of such rivet, in relation to the rib means which are contiguous to the arcuate-shaped scoreline, and extending toward such remaining longitudinal end of such tear strip, within a second longitudinal segment of such tear strip extending to distal ends of such scoreline legs. 9. The structure of claim 8 in which such wall panel comprises an endwall panel forming part of an unitary sheet metal end closure structure for a beverage container; and such end closure structure includes chime seam metal symmetrically spaced from the geometric center of, and disposed peripherally of, such endwall panel, and the scoreline means, for the elongated tear strip, defines a pour opening for such container on which such end closure structure is used. 10. The structure of claim 9 in which such endwall panel is recessed symmetrically from such chime-seam metal in an axial direction so to be disposed toward the interior of such a beverage container when such end closure structure is in use, and, further including a chuck wall extending in such axial direction from such chime seam metal toward such recessed endwall panel. 11. The structure of claim 10 in which such U-shaped movable tear strip is located with the arcuate-shaped scoreline at such closed end of such tear strip disposed toward such chuck wall, such that the elongated scoreline legs defining such tear strip are directed toward a location contiguous to the geometric center of such endwall panel. 12. The' structure of claim 11 in which such scoreline legs at the remaining longitudinally-opposite end of such movable tear strip terminate contiguous to the geometric center of such endwall panel to maintain such tear strip, as moved from its original contour, unitary with surrounding sheet metal of such wall panel, such that the elongated U-shaped movable tear strip and such integral opener are retained on the endwall panel after such tear strip movement defines such pour opening for such container, and, also, are retained within the periphery of such chuck wall after such opening with such opener in overlaying relationship to sheet metal of such tear strip without obstructing such pour opening. 13. The structure of claim 10 in which such chuck wall helps to define buckle-resistant profiling for such endwall panel, such buckle-resistant profiling comprising sheet metal recessed axially toward the interior of such container forming a profiling indentation in circumscribing relationship to such endwall panel. 14. The structure of claim 13 in which such endwall panel further includes a bead projecting from such panel in an external direction in relation to such container, such projecting bead being located inboard of and contiguous to such peripheral profiling indentation. 15. The endwall closure structure of claim 14 in which such endwall panel has a circular configuration in plan view, and such buckle-resistant profiling indentation and such projecting bead extend around the full periphery of such circular configuration; and, in which, the sheet metal of such endwall closure structure is selected from the group consisting of a flat rolled steel substrate in the range of about 75 #/bb to about 110 #/bb, with residual metal of such scoreline means having a thickness in the range of about .001" to about .0035" and a flat rolled aluminum substrate having a thickness gage of about .010" to .015", with residual metal of such scoreline means having a thickness in the range of about .0040" to about .0055". 16. The structure of claim 11 in which such chuck wall extends symmetrically from such peripheral chime-seam metal to a level axially interior of the level of such endwall panel with respect to a container on which such end closure is used; such chuck wall forming part of profiling indentation means symmetrically disposed about the full periphery, of such endwall panel; and, in which such endwall panel further includes a projecting bead contiguous to and inboard of such recessed profiling toward the geometric center of such endwall panel, such projecting bead extending externally with respect to such container and being located in such endwall panel to augment rigidity of such endwall panel so as to substantially decrease or eliminate flexing of such panel from its original contour during such rupturing of such scoreline means by such integral opener. 17. The structure of claim 8 in which such endwall panel has a circular configuration in plan view, and such movable tear strip folded position disposes such handle end of the integral opener within the chuck wall, with such longitudinal segments of the movable tear strip in overlaying relationship to each other and to a portion of the external surface area of the endwall panel which is exterior to the periphery of such pour opening defined by such scoreline means, with such opener in overlaying relationship to such folded segments and located diametrically opposite to the location of such initial rupture of such tear strip. 18. Method for fabricating an easy-access sheet metal endwall panel for a container, comprising providing flat rolled sheet metal, fabricating such sheet metal to provide an endwall panel of substantially planar contour for a container, and further including the steps of scoring such endwall panel to establish scoreline means at which thickness of such sheet metal is decreased, such scoreline means defining an elongated tear strip which is substantially symmetrical with relation to its central longitudinal axis, such scoreline means including: an arcuate-shaped scoreline and a pair of linearly extended scoreline legs, such scoreline legs being symmetrically disposed one each on lateral sides of such axis, and, extending from such arcuate-shaped scoreline with the major component of direction of each such scoreline leg being substantially parallel to or converging at an angle of about one and one half degrees toward such central axis of the tear strip; profiling such tear strip by impressing elongated shallow-depth ribs in such tear strip sheet metal with the major component of direction of such ribs extending longitudinally of such tear strip, such profiling step being carried out contemporaneously with such tear strip scoring step; providing an elongated sheet metal opener having a working end and a handle end at opposite longitudinal ends of its central longitudinal axis; securing such opener to the elongated tear strip utilizing sheet metal of such elongated opener which is contiguous to its working end and sheet metal of the elongated tear strip contiguous to the arcuate-shaped scoreline; such elongated opener as secured being disposed in overlaying relationship to such tear strip with the central longitudinal axis of such opener extending with its major component of direction substantially the same as the major component of direction of such central longitudinal axis of the elongated tear strip; and forming a peripheral portion of such endwall panel so as to substantially decrease or eliminate flexing of such sheet metal during opening of such container. 19. The method of claim 18 including scoring such panel sheet metal such that the arcuate-shaped scoreline is located contiguous to such peripheral portion of such endwall with such elongated scoreline legs being directed toward sheet metal contiguous to the geometric center of such endwall panel. 20. The method of claim 19 in which forming of such peripheral portion of the endwall panel includes forming a peripheral bead which protrudes in an axial direction which is external in relation to such container, and, in which the mid-point of such accurate-shaped scoreline is contiguous to such protruding bead while being inboard thereof toward such geometric center. 21. The method of claim 18 in which the elongated sheet metal opener is secured to the elongated sheet metal tear strip by forming a unitary rivet such that an initial-contact edge of such opener is located along the central longitudinal axis for such opener at its working end, and such opener is oriented for contacting such tear strip contiguous to the mid-point of the arcuate-shaped scoreline upon movement of the handle end of such opener in a direction away from the external surface of such wall panel with such rivet means acting as a fulcrum to cause initial rupture of .such arcuate-configuration scoreline by Class 1 lever action. 22. The method of claim 21 further including forming such elongated opener to present pivot- point contacts which are recessed longitudinally in relation to such initial-contact edge at the working end of such opener, such pivot-point contacts coming into contact with panel sheet metal located in such panel external to such scoreline defining such opening to establish fulcrum means for rupture of such scoreline legs by Class 2 lever action. 23. The method of 21 including selecting the location of such rivet, length of such elongated opener, length of such tear strip and placement of such profiling in such tear strip so as to dispose such folded tear strip and opener in overlaying relationship within the chuck wall of such endwall closure upon completion of opening of such container. 24. Method for forming sheet metal end closure to provide easy-access features for use of an integral opener, comprising forming a sheet metal blank to provide peripheral chime seam metal circumscribing a substantially planar endwall panel recessed axially from such chime seam metal in the direction of the interior of a container on which such end closure is to be used, with an axially oriented chuck wall interconnecting such chime seam metal and endwall panel, such chuck wall extending to a level axially interior of such endwall panel and returning axially to such panel so as to form buckle-resistant profiling for such panel about its full periphery, and forming a projecting bead to decrease axial flexibility of such recessed panel, such projecting bead extending axially from the plane of such endwall panel in a direction which is exterior in relation to such a container, such projecting bead being located about the periphery of such panel contiguous to such buckle- resistant profiling. 25. Integral structure for providing easy- access to a sheet metal end closure for a container, comprising an elongated unitary opener fabricated from flat- rolled sheet metal of preselected thickness gage, such opener being symmetrical about its central longitudinal axis and presenting a working end and a handle end at longitudinally opposite ends of such axis, such working end presenting severed edge metal pointed configuration with its pointed edge located along such centrally located axis and with severed edge metal receding toward the remaining handle end of such opener, a distance longitudinally equal to at least five times such flat rolled sheet metal thickness gage, with remaining edge metal about major longitudinal and lateral peripheral portions of such opener curled to strengthen such opener longitudinally and laterally. 26. The structure of claim 24 in which such elongated opener is fabricated with an aperture contiguous to its working end for receiving a rivet button, for securing such opener to an end closure for a container, and such pointed edge located along such central longitudinal axis at the working end of such elongated opener is located at a level which is recessed toward the interior of the container on which such end closure it is to be used, with such severed edge metal receding from the recessed level of such pointed edge at the central longitudinal axis of such opener toward the level of such curled edge metal surrounding the remaining periphery of such opener. 27. Method for fabricating a sheet metal opener for integral use with an easy-access sheet metal wall panel, comprising providing an elongated strip of flat rolled sheet metal of predetermined gage for carrying out a progression of fabricating steps, including: draw processing a recessed panel for location of an aperture for receiving a rivet button for making such opener integral with an easy-access wall panel, punching such aperture in such panel, cutting such sheet metal to form a working end for such an opener, a handle end for such opener, and a pair of lateral sides, one each on opposite lateral sides of such central longitudinal axis and extending between such working end and such handle end of the elongated opener, such working end being cut with a pointed configuration, such lateral sides converging toward the pointed working end of such opener while presenting a lateral width for such opener which is greater than the width of such working end, curling edge metal along such lateral sides and handle end of such opener, forming a curled edge such that raw edge metal from cutting such sides and handle is guarded from access within such curled edge, such curled edge metal extending along such converging lateral sides of the opener and terminating contiguous to such working end at a location spaced on each side of such central longitudinal axis and from such pointed edge, then, draw forming such working edge metal between to dispose such pointed edge toward such panel with raw edge metal extending from such pointed edge toward such terminating locations for curled edge metal.