DISC REMOVAL END WALL STRUCTURE WITH SAFETY FEATURES

Abstract: A full-open end wall structure (27) comprises a back scoreline central portion (40, 52) which is ruptured by Class 2 lever action upon lifting of a longitudinally rigid (non-lanced) tab opener (30, 51); the back scoreline legs (35, 36; 53, 54) help to determine the fulcrum axis for the tab opener (30, 51) as chisel point (33) at its working end ruptures a minor portion of peripheral scoreline (34) by Class 1 lever action. Continued movement of the handle end (37) of tab opener in the direction (46) toward the user, into contact with chime seam (47) provides for continued lever-action rupture of the peripheral scoreline by Class 1 lever action in which the chime seam acts as the fulcrum. Multi-layer folds of sheet metal, providing between layers transition-zone rounded-edge metal (73, 78) for shielding the raw edge of ruptured residual scoreline metal, are prefolded on the removable disc portion and that portion of the end closure structure which remains with the container.

Description: DISC REMOVAL END WALL . .STRUCTURE .WITH A _ E -L- TUJ?ES This application is a continuation-in-part of Inter¬ national Application No. PCT/US37/06249 , filed September 29, 1987 which is a continuation-in-part of International Application No. PCT/US87/00102 , filed January 23, 1987 and this application claims the priority of both such earlier filed applications for all common subject matter. This invention relates to full-open, disc-removal, convenience- eature, sheet metal end-closure structures, to methods for fabricating and opening such structures, and to safety prov-isions for obstructing access to raw edge metal remaining along a severed scoreline after opening such a closure structure. With prior convenience-feature, full-open sheet metal end closures of the disc pull-out type, after initial rupture of a portion of a peripherally-located scoreline, it was necessary to pull bac wardly on an open.-ring in- the handle end of the pull-tab opener to continue severance of the remainder of the peripheral scoreline. Past efforts to facilitate removal of end panel discs by such "pulling-out" methods included special scoreline configurations (e.g. U.S. Patents 3,768,392 of October 30, 1973 and 4,182,400.of January 8, 1980), and panel profil¬ ing techniques (e.g. U.S. Patents 3,655,091 of April 11, 1972 and 3,724,709 of April 3, 1973). Also, tab openers for prior art disc pull-out structures were often lanced υτε SHEET (rather than being longitudinally rigid) in order to make • initial lifting of the handle end easier. In such prior end closure structures, lever-assisted rupture was limited to only a minor portion of the peripheral scoreline during the initial rupturing proce¬ dure. ' Thereafter, pulling backwardly on the tab opener ring had to be relied on to continue severance of residual metal along the remaining major portion (about 90%) of the peripheral scoreline after such initial lever action rupture. Convenience-feature end closures, as previously available commercially, offered minimal opportunity for mechanical advantage in removing an end panel; i.e., lever-action assistance for scoreline rupture was used for only a minor portion of the peripheral scoreline and was limited to the initiation stage of the removal procedure. Such difficulties in opening full-panel end wall struc¬ tures of the prior art substantially excluded steel end closures from the market. Such difficulties have been overcome by contributions of the present invention. The present invention provides for lever-action ease of opening during severance of the peripheral scoreline which defines a full-open disc for removal from the end closure. Also, an elongated, longitudinally-rigid tab-opener structure increases available lever action. A solid 3 configuration handle end, i.e. free of any finger opening, can be used and, is preferred in order to help discourage an attempt to pull backwardly on the handle end of the opener from a location which lies internally of a longi- tudinal projection of the container side wall. Further, the present invention . provides a new disc¬ removal procedure and means for establishing use of such new procedure with the elongated, longitudinally-rigid opener enabling lever-assistance for peripheral scoreline severance as the handle end of the opener is disposed at a location radially external of the periphery of the end closure. In addition, new structures and methods are combined to enable shielding of residual peripheral scoreline metal in a manner not previously available are made commercially practicable with flat rolled steel. Previously proposed safety-edge measures include U.S. Patents 3,334,775 of August 8, 1967 and 3,986,632 of October 19, 1976. The present invention provides for folding multi-layers of sheet metal, including flat rolled steel, for shielding the raw edge of severed scoreline metal, without detriment to accurate depth scoring of the sheet metal or premature damage to the residual scoreline metal. These and other advantages and contributions are con- sidered in greater detail in describing embodiments of the invention shown in the accompanying drawing; in these SUBSTITUTESHEET drawings : FIG. 1 is a plan view of the outer or "public" surface (in relation to a container.) of an end closure structure of the invention shown with integral opener in place for opening; FIG. 2 is a bottom plan view of the inner or "prod¬ uct" surface (in relation to a container) showing the positional interrelationship of back scoreline means with rivet means for securing such opener to the panel to be removed from such closure structure; FIG. 3 is a 'enlarged, outer-surface, plan partial view, without the opener in place for better viewing purposes, for decribing the back scoreline means, its placement and its contributions . to the invention; FIG. 4 is a schematic cross-sectional partial view of an end closure structure of ' the invention on a container with the integral opener in position prior to initiating scoreline rupture; FIG. 5 is a schematic cross-sectional partial view of the end closure structure of FTG. 4 subsequent to initia¬ tion of rupture of the back scoreline and a portion of the peripheral scoreline for defining the starter segment of the removable panel; FIG. 6 is a schematic partial view, sequential to that of FIG. 5, showing completion of an initial rupture phase in which such starter segment is moved from its SUBSTITUTESHEET original position in the end wall panel of the end closure structure; FIG. 7 is an outer-surface plan view after continua¬ tion of the arcuate movement of the tab opener to bring such opener into contact with chime seam in a position to continue severance of the peripheral scoreline, beyond that portion partially defining the starter segment, using the chime seam as the fulcrum enabling subsequent lever action in accordance with the invention; FIG. 8 is an inner-sur ace plan view of the end wall structure at the opening stage of FIG. 7 with interconnec¬ tion between the tab opener starter segment and remainder of the end wall panel in accordance with the invention providing continued severance of the remainder of the peripheral scoreline by lever action using the chime seam as a fulcrum; FIG. ' 9 is a partial schematic view in cross-section of structure in accordance with the invention for describ¬ ing the Class I lever action which continues severance of the peripheral scoreline using the chime seam as a fulcrum; FIG. 10 is a schematic cross-sectional view, subse¬ quent to FIG. 9, for showing the "crow-bar" function of the longitudinally-rigid opener using Class I lever action about the chime seam as the fulcrum in which the severable panel moves in an axial direction externally away from the ESHEET container in accordance with the invention; FIG. 11 is a bottom plan view for showing a preferred back scoreline con iguration which further increases the mechanical advantage available with teachings of the present invention and provides other advantages; FIG. 12 is an outer-surface plan view of the end closure structure of FIG. 11 showing the starter segment resulting from rupture of the back scoreline and a minor portion of the peripheral scoreline in an intermediate opening stage; FIG. 13 is a top plan view of a preferred specific embodiment of the end closure structure of the invention showing positioning of the opening instructions, as taught herein, to facilitate use of the new disc-removal proce- dure of the invention; FIG. 14 is a cross-sectional view of the end closure structure of FIG. 13, taken along the line 14-14 of FIG. 13; FIG. 15 is a perspective view, at the initiation of the opening procedure, of the end closure structure of FIG. 13, mounted on a can body, showing the proper orientation for disc-removal brought by placement of the opening procedure instructions as taught herein; FIG. 16 is a perspective view, sequential to that of FIG. 15, showing more clearly rupture of the scoreline defined portions of the starter segment as the handle end TESHEET of the tab opener is moved through an arc of around 90° ; FIG. 17 is an enlarged perspective partial view, sequential to that of FIG. 16, showing the location of the lever fulcrum contiguous to the longitudinal location of the rivet along the length of the opener as the rupture of the peripheral scoreline, beyond the initial phase, takes place by force applied to the opener from a location radially exterior of the periphery of the end closure; FIG. 18 is a perspective view, sequential to that of FIG. 17 showing continued "crow-bar" action disc removal as the arcuate movemen of the handle end of the integral opener continues beyond 180° externally of the periphery of the can causing the severable end wall panel to be moved in substantially its original planar form from the container; and FIG. 19 is a perspective view sequential to that of FIG. 18, showing the final stage of disc removal by lift¬ ing on the opener, retained by the disc, from the con¬ tainer; FIGS. 20 through 25 are partial cross-sectional views, taken radially of the .end closure structure, for describing the sequential steps in accordance with the invention for coordinated formation of shielding for raw- edge scoreline metal by folding multi-layers of sheet metal, for scoring the sheet metal, for forming a unitary rivet button, for end wall panel profiling and embossing, and for riveting a tab opener to be integral with the removable disc, in which: FIG. 20 shows the results of shaping a cut blank to provide chime seam metal, a chuck wall and sheet metal portions extending in stepped fashion, radially-inwardly in relation to the end closure structure and in an axial direction in relation to a can body for receiving such end closure structure, toward an end wall panel which is recessed axially in relation to such chime seam metal toward the interior of such a container used with such end closure, FIG. 21 shows start of rivet button formation and an initial stage for subseguent folding of such sheet metal portions in a sequence subseguent to that of FIG. 20, FIG. 22, which is sequential to FIG. 21, shows formation of a smaller diameter rivet button, an inter¬ mediate stage in the folding of such sheet metal portions, and start of recessing of a centrally located panel portion, FIG. 23, which is sequential to FIG. 22, shows peripheral and back scoreline formation, with such scorelines being formed immediately prior to final orientation of either of a pair of multi-layer folds of sheet metal contiguous to the peripheral scoreline on opposite surfaces of such end closure. FIG. 24, which is sequential to FIG. 23, represents SUBSTITUTESHEET the sequence for final rivet button shaping and final orientation of a multi-layer fold of sheet metal for shielding residual scoreline metal of the removable disc to be separated from the end closure structure and for embossing the end wall panel with instructions as shown in FIG. 13, and FIG. 25 shows the rivet button formed into a rivet securing a tab opener to the disc and final orientation of the multi-layer fold of sheet metal for shielding the residual scoreline metal of that portion of the end closure structure remaining with the container. The present invention provides procedure and struc¬ ture which make lever-action and mechanical advantage severance available substantially throughout, or through- out the major portion which is significant for ease of opening, of a peripheral scoreline defining a panel to be removed for full-opening of a container. Endwall closure structure 27, shown in plan view of its outer surface in FIG. 1, is formed with chime seam metal 28 around its outer periphery; a longitudinally- rigid tab opener 30 is secure to removable disc 31 by rivet 32. The working end 33 of elongated tab opener 30 is positioned in contiguous relationship to a portion of peripheral scoreline 34; the latter has a circular con- figuration in such plan view and defines removable disc 31. SUBSTITUTESHEET Back scoreline leg portions 35, 36 (FIGS. 1 and 2) • extend in transverse relationship to the diametric align¬ ment of the longitudinal axis of opener 30. Such legs 35, 36 define, at least in part, a chord across a minor portion of the circular peripheral scoreline 34 which helps to define a part of a starter segment which is first moved from its original disposition in the plane of the end wail panel. The elongated tab opener- 30 is non-lanced (no part moves relative -to another part) and is fabricated to have appropriate longitudinal strength characteris ics for the functions disclosed herein. For example, sheet metal of a suitable gage is selected, and the tab opener is rein¬ forced longitudinally,, to enable it to act as a longitud- inally rigid, high-strength lever throughout severance of a full panel disc. Also, a solid con iguration for the tab opener 30, free of any ring pull opening at or near its handle end 37, is taught herein to discourage pulling backwardly on the handle after the initial rupturing procedure for the starter segment. The handle end of the tab opener is located over a centrally-located, profiling indentation 38 which is of circular configuration in plan view. Such indented portion of the panel maintains disc 31 substantially planar and helps to provide finger access for initiating 11 arcuate movement of the handle end of the tab opener in a direction externally away from the container to initiate opening. The back scoreline configuration of the embodiment of FIG. 1. is shown more completely in the bottom plan view of FIG. 2, in which the end closure structure is seen as it appears on the "inner" surface of the structure which will confront product held by a container, after assembly. The back scoreline legs 35, 36 stem from rivet-circumscribing center section 39 of the back scoreline means, in the direction of the adjacent periphery of the end wall closure 27. Center scoreline section 39 is disposed about the periphery of a portion of rivet 32 (FIG. 3). In the embodiment shown, it is formed from multiple radii so that a portion 40 protrudes relative to circumferential portions 41, 42 in a radially inward direction. A smaller radius (in relation to that of 41, 42) provides a semi- pointed con iguration which ruptures readily to vent the container upoft initial lifting of the handle end 37; such initial rupturing occurs while tab opener 30 is still in a position substantially overlaying scoreline section 39. Arc portions 41, 42 of scoreline section 39 lead to legs 35, 36. Back scoreline legs, such as 35, 36, are directed toward an adjacent portion of the peripheral scoreline 34 and define an effective -included-angle therebetween of 180° SUBSTITUTESHEET in the embodiment of FIGS. 1-3. Such legs can be scored to provide for folding or severing a portion of the sheet metal to form a chord (better seen in later FIGS-. 7 and 8) for the subtended arc portion of the circular disc defined by scoreline 34. The effective included angle confronting the adjacent portion of peripheral scoreline 34 is selected to be no greater than 180°; and in other embodi¬ ments, described later herein, is preferably substantially less than 130°. Scored legs 35, 36 help to define starter- segment 45 (FIG. 3) which is a minor area of the circular panel 31. A portion of segment 45, between its chord and the chord's subtended arc is turned inwardly of the container by the opening procedures prior to full panel severance. The scored legs 35, 36 terminate before intersection with the peripheral scoreline; they are part of such chord which, in the embodiment shown, is positioned radially inwardly of center 44 of rivet 32. The resulting chord in this embodiment acts as an interim fulcrum for Class I lever action of opener 30 during rupture of a portion of the subtended arc of the peripheral scoreline. The area of . the segment 45, which is turned toward the interior of a container, is increased by location of legs 35, 36 to form a chord radially inwardly of rivet center 44, over that which would be provided if the chord were oriented to pass through the center of, or radially outwardly beyond the UBSTITUTE SHEET 13 center of rivet 32. Other important configurational aspects of the back scoreline legs are considered in greater detail later herein. Initial rupturing stages of the invention, using the embodiment of FIGS. 1-3, are shown in sequence in FIGS. 4- 6. Arrow 46 indicates the arcuate direction of movement of the handle end of opener 30; this direction of arcuate movement of the handle end of an opener is utilized in the invention for lever action severance of peripheral scoreline throughout the opening procedure. Initially, the handle end is -* started on its aracuate movement by lifting (with a finger, other than the thumb, as shown later herein) in a direction toward the user as such handle end moves initially away' from the outer * surface of the end wall panel 31. For nomenclature purposes, note that the peripheral chime metal 28 of FIGS. 1 and 2 is formed into chime seam 47 and that the upper surface of metal 28 constitutes the exposed (upper) surface of chime seam 47 as shown in the cross sectional views of FIGS. 4-6. Also note that end wall panel 31 is countersunk in relation to the axial disposition of such upper surface of chime seam 47; and that the centrally located profiling portion 38 is recessed axially from the remainder of end wall panel 31. Rupture of the rivet-circumscribing, portion 39 of the back scoreline and start of rupture of a minor arc SUBSTITUTESHEET 5407 ' 14 portion (partially defining starter segment 45) of the peripheral scoreline 34 are shown in FIG. 5. After initial rupture, the arcuate movement of the handle end of opener 30 is continued in the same direc- tion; the angular direction of the legs of the back scoreline means toward the adjacent peripheral scoreline helps to determine size of the starter segment. In the embodiment of FIGS. 1-3, the scored legs 35, 36 contribute to defining starter segment 45. After the initial ruptur- ing procedure of FIG. 5, instead of pulling backwardly (as in the prior art) on the tab opener 30, the movement of the handle end of tab opener 30 ' is continued in the arcuate direction into an upright position as shown in FIG. 6 (and beyond as shown in FIGS. 7, 8 and 9). The chord, determined by the " direction of the scored lines of legs 35, 36 acts as the pivot (fulcrum) axis rather than the center 44 of rivet 32, and stops any radial direction translation of opener 30 so that working end 33 turns inwardly to rupture peripheral scoreline portion 48. Such arcuate movement of the handle end of the opener in the direction 46 continues through an arc in excess of 90 until that -surface of tab opener 30, which initially faced as shown in FIG. 1, is brought into contact with the surface of chime seam 47 (FIGS. 7-9). In the embodiment of FIGS. 7-10, the working end 33 of opener 30 acts through a portion of segment 45 on the remainder of disc SUBSTITUTE SHEET 31 after the peripheral scoreline portion 48 (FIG. 8) is ruptures. Segment 45 defined by the chord ( ormed in part by legs 35, 36) and the ruptured portion 48 of the peripheral scoreline is shown as it appears from the inner surface of an end closure structure in FIG. 8. The contact between the elongated opener 30 and the chime seam 47 (FIGS. 7-10) acts as a fulcrum for continued lever-action severance of the peripheral scoreline 34 (such continued lever-action taking place with the hand of the user being located radially exterior of the periphery of the chime seam and " conainer side wall); the continuing arcuate movement (arrow 46, FIG. 10) of the handle end of opener 30 causes Class I lever action output, at the working end ' 33 of opener 30 in the direction of arrow 50 of FIG. 10. The lever acts as a "crow-bar" about the chime (fulcrum) to move the panel 31 (also referred to herein as a disc) in an outward direction in relation to the container, completing lever-action severance of the remainder of the peripheral scoreline 34. As shown in FIG. 10, the full disc 31 is moved upwardly from its countersunk position by such lever action, severing most, if not all, of the remainder of the scoreline 34 (FIG. 3) around disc 31 with the upper surface of chime seam 47 acting as the fulcrum for such continued lever action. The tab opener remains secured to the removable disc through segment 45 which remains joined SUBSTITUTE SHEET 5407 16 to the remainder of the disc 31 by the residual metal, if any, along legs 35, 36 but, more importantly, by the metal, beyond the ends of such legs, which comprise safety "shielding" for raw edge severed metal as described later herein. The disc 31, when severed about its periphery, e.g. as shown in FIG. 10, can be readily lifted away from the open container. The lever action which moves the working end 33 of opener 30 in the direction of arrow 50 severs peripheral scoreline toward that portion of the peripheral scoreline 34 which " is diametrically opposite to the initially ruptured portion. As rupture of the peripheral- scoreline is converging to complete severance of the disc 31, the force required for removal is diminishing so that the "crow-bar" action requirements are diminishing and, the end wall panel can be lifted from the closure struc¬ ture with any minor remaining peripheral scoreline being severed by such lifting. An important part of the present concept involves the advantages available in the placement and configuration of the back scoreline. In a preferred embodiment shown in ' FIGS. 11 and 12, the area of the starter segment of the disc is decreased in a manner which significantly in¬ creases the mechanical advantage available through tab opener lever action over that available with the config¬ uration of FIGS. 1-3. Also, the portion of the end wall panel initially folded inwardly of the container is minimized so as to be insignificant. A more complete view of the back scoreline configura¬ tion is available in the (inner surface) plan view of FIG. 11; and the tab opener 51 is seen on the outer surface view of FIG. 12. Such back scoreline means (FIG. 11) include a rivet-circumscribing central portion 52 and angled legs 53, 54 which define an effective included angle which is substantially less than 130 ° . In the illustrated embodiment legs 53, 54- have a curvilinear configuration initially extending transversely to a diameter of the panel and then in a generally radial direction toward adjacent peripheral scoreline 34. The effective included-angle between legs 53, 54 is a minor acute angle; such legs help to define a starter segment of significantly less area in relation to the disc to be removed than that of the embodiment of FIG. 3. Scoring for the legs terminates at points 55, 56 contiguous to shielding means (on the end wall panel) to be described in more detail later herein. Chord 57, shown in broken lines, ends contiguously to termination points 55, 56 at such shielding mens. The portion of the periphery scoreline which is ruptured during the initial rupturing procedure is the arc subtended by chord 57. Starter segment 58 (FIG. 12) is proportionally smaller than segment 45 of the earlier-described FIG. 3 407 18 embodiment; also the rivet can be placed significantly closer to the working end. As a result, the effective length of the opener acting as work-input lever arm is increased during a portion of the initial rupturing procedure and, also, subsequently due to the increased length of the opener which is disposed radially outwardly of the chime seam for the container, which chime seam acts as the fulcrum for the latter lever action. The back scoreline means of FIG. 11 is scored for severing about central portion 52 and along the angled legs 53, 54. The angled legs turn toward the adjacent peripheral scoreline with a major directional component the same as the longitudinal axis of the elongated opener 51. That this configuration can be used without concern for completely ripping a minor area starter segment from the removable disc is due to the multi-layer sheet metal fold teachings, for shielding raw-edge residual scoreline metal, shown and described in relation to later figures. Such sheet metal shielding folds prevent starter segment 58 (Fig. 12) from being town completely from the remainder of the disc and enable maximizing the mechanical advantage available through this back scoreline configuration while maintaining the unitary connection, between segment 58 and the remainder of the end wall panel, to continue lever- action severance of the peripheral scoreline. It should be noted that the action of " completing 5407 19 severance of the disc takes place while acting on the handle end of tab opener 51 while such handle end is disposed radially externally of the container periphery; and, while outside a projection of the peripherally- located scoreline. This provides an added safety feature by eliminating any tendency to grasp the disc being severed; and, also, eliminates or minimizes spillage of liquid or semi-fluid contents which tended to occur with the prior art method of "pulling backwardly" on a "ring pull." The non-lanced '(longitudinally rigid) tab opener 51 partially shown in bottom plan view in FIG. 12 includes fold-over rounded-edge metal, such as 59, around its outer periphery except near its working end. Such longitudinal- ly-extending rounded edge metal increases the longitudinal strength of tab opener 51 for lever action purposes. Profiling of the tab opener such as 60 surrounding rivet 37 (FIG. 13) can also add to that longitudinal strength. Increasing the length and longitudinal strength of the tab opener facilitates the opening procedures taught herein. A chisel point, such as 33 (FIG. 8) provided at the working end of an opener, facilitates the initial puncture which starts rupture of the peripheral scoreline. The specific embodiment of FIG. 13 shows aspects not shown in FIGS. 11, 12, such as protrusions 61 and 62 which are convex in relation to the outer surface in FIG. 13. UBSTITUTESHEET Protrusions 61, 62 are used in alignment and stacking; and, are located along a line which is intermediate the center of the end wall panel and the center of the rivet ' , on opposite sides of a radial line between such centers, in order to serve most effectively for alignment and stacking. Also, linearly-extended, outwardly-projecting profil¬ ing bar 65 is positioned at a location below the handle end of the tab opener 51 so as to position such opener horizontally when forming rivet 32; and, also, to help maintain desired access at the working end for opening. The direction of such profiling and alignment protrusion can be seen more clearly in the cross section view of FIG. 14. An important contribution of the invention involves the predetermined placement of opening instuc ' tions 66 (FIG. 13). Referring to FIGS. 15-19, which are used to describe the new disc-removal opening procedure of the invention, the placement and the orientation of such instructions diametrically opposite . to the location for the tab opener orients the end closure properly so that the handle end of the opener, upon lifting, can be swung in an arc toward the user. Such direction of arcuate movement is continued (as the arc exceeds 90 ° ) over the side of the container using the chime -seam as a fulcrum to provide leveraged severance of the peripheral scoreline beyond the initial starter segment portion. The index or middle finger is used for initiating disc removal in the new opening method rather than attempting to force the thumb under the handle end of the tab opener as in prior disc removal methods. As seen in FIGS. 13 and 15, 16, placement of the instructions 66 requires orienting of the end closure so that the index or middle finger is used in order to be able to read such instructions (unobstructed by the hand of the user). The thumb, at such stage, is braced against the chime seam 47 and the container side wall. The handle end of tab opener 51 is lifted by the index and/or middle finger (FIG. 15) in a direction externally away from the container initially. The swing of the handle end (as shovm in FIG. 16) continues toward the user. In effect the handle end of tab opener 51 is initially lifted away from the end wall panel and is swung in an arc by pulling such handle end toward the user until tab opener 51 contacts the chime seam; which contact is being initiated in FIG. 16 (slightly after about 90 of arcuate movement) and continues in the sequence shown in FIGS. 17 and 18. As shown in FIG. 17 the tab opener 51 contacts the chime seam 47, at a location along the length of the opener which is about the same as the location of the rivet 32 along the length of the opener. The starter SUBSTITUTE SHEET segment 58 remains unitary with the disc as the peripheral scoreline is severed by such lever action. This arcuate movement of the opener, with the chime acting as the fulcrum for the lever action, is continued as shown in FTG. 18. The end wall panel 31 remains substantially planar, assisted by the profiling of central portion 38, as the lever action of opener 51 severs the periphery of the panel. The lever-action severance of the peripheral score- line, as taught herein, provides smoother opening charac¬ teristics than was possible with any of the prior art full-panel opening techniques. In the prior art there was an abrupt change of direction from the limited lever action, applied only during initial rupture phase, to the "pull backwardly" phase. Frequently the result was spillage of liquid or semi-liquid contents because of such abrupt change, in direction of applied force; and, also because of abrupt movements during such backward pulling. In addition to the smooth continuous lever-action sever- ance, the opening procedure taught generally results rather naturally in placement of the container on a level surface during opening. Enabling lever-action severance of the peripheral scoreline substantially eliminates the likelihood of spillage during execution of the opening procedure. As such leveraged severance in approaching complete- TE SHEET ness, the end wall portion as defined by scoreline 34 can be lifted from the closure as shown in FIG. 19. This may occur as severing of the scoreline 34 is converging diametrically opposite to the location of the starter segment 58. The novel features described herein which make fabrication of end closures from flat rolled steel commercially practicable also facilitate opening of end closures made from aluminum. FIGS. 20 through 25 are radial, cross-sectional, partial views for purposes of describing sequential stages in the formation of' the end closure structure including shielding means for the raw edge metal remaining after severing of the peripheral scoreline. FIG. 20 shows results of an early forming operation on a blank involving forming of the chime seam metal and countersinking the end wall panel in relation to chime metal 28. . Viewed in. radial cross-section, chuck wall 69 and a series of "steps and risers" lead to the countersunk portion. Such steps and risers, generally designated 70, are part of the sheet metal portions for forming a pair of multi-layer folds of sheet metal; one such fold for shielding residual raw edge metal remaining with the disc after tearing the peripherally located scoreline and, one for shielding residual raw edge metal on that portion of closure structure remaining with the container. The step and riser portions of these multi-layer ITUTE SHEET 5407 24 folds of sheet metal are joined to each other, and at each end to the chuck wall and end v/all panel respectively, by transition zones of compound, curvature (i.e. curvilinear in a plane which is perpendicularly transverse to the central axis of the container and, also, rounded in radial cross section). Referring to FIGS. 20, 21 step portion 71 ' leads to riser portion 72 through intermediate transition zone 73; step portion 74 is connected to riser portion 72 through curvilinear zone 75; step portion 74 leads to riser portion 76 through transition zone 77; and riser portion 76 leads to transition zone 78 formed with panel 31. In carrying out the procedures of FIGS. 20-25, the timing of the scoring action and the multi-layer folding action, and the extent to which multi-layer prefolding is carried out prior to formation of the peripheral scoreline 34, are important considerations. The peripheral scoreline for the removable disc is to be disposed intermediate the pair of multi-layer folds which separately shield residual scoreline metal on the separated disc and on the container end structure. The procedure taught enables tooling access, beyond the multi¬ layer pre-fold on each surface of the end closure, to enable scoring of a single thickness of sheet metal; the latter is supported oppositely to the scoring tool on the remaining surface. The prefolding of the sheet metal layers provides for completing the folding action, around such circular periphery, with only slight movement of rounded transition zone metal being required' after scoring to thus avoid premature damage to residual scoreline 5 metal. In the operation of FIG. 21 (which is sequential to ' FIG. 20) an initial rivet button configuration 80, having a broad-diameter shallow-dome shape in cross section is formed. Also, the sheet metal "step" portion 74 is 10 oriented horizontally as shown; peripheral scoring (34) will subsequently take place on such horizontally oriented metal portion 74 to be located radially intermediate the pair of multi-layer folds to facilitate opening and avoid obstruction during removal of disc 31. 15 Multi-layer folding of the sheet metal, scoreline formation, rivet button and profiling formation, and riveting a tab opener to the disc are coordinated while optimizing the number of work strokes. In addition to the above enumerated advantages of scoring a single layer of 20 metal and avoiding premature damage to residual scoreline metal, the rivet button formation and riveting actions are carried out in sequence without interfering with the metal folding or scoring operations. Completing the final configurations for the projections 61 and 62, the support 25. bar 65 and embossing 66 can be carried out simultaneously with formation of the rivet button and the profiling to c UBSTITUTE SHEET .form recessed panel 38. As carried out in the sequences shown in FIGS. 23-25, metal portions 71 , 72 and compound curvature zone 73 will form a multi-layer fold for shielding the raw edge metal 5 remaining with the end closure structure on the container. Metal portion 74 will be the connector between the pair of multi-layer sheet metal folds; also, the peripheral score¬ line 34 which will define the removable panel 31, will be carried out on metal portion 74. Metal portion 76 is 0 joined to the horizontal intermediate portion 74 by compound curvature z'one 77; compound curvature transition zone 78 and a portion 82 (of the recessed panel adjacent to zone 78) complete the multi-layer fold for providing the shielding for the residual raw edge metal remaining j _5 with the severed disc 31. In FIG. 22, a smaller-diameter, greater-depth rivet button 83 is formed and the pre-folding of the metal portions 76, 82 about zone 78 is increased, as shown. In the illustrated embodiment, multi-layer folds of 20 metal for shielding both the scoreline residual metal on the disc and that remaining with the end structure on the container are provided. Another method (not necessarily part of the prior art) for protecting the residual score¬ line metal remaining with the container by profiling of a 25 container side wall has certain disdadvantages in dimin¬ ishing container volume. The embodiment of FIGS. 20-25 SUBSTITUTE SHEET ■ 27 does not diminish container contents and provides an increased area opening for dispensing container contents. In FIG. 23, the folded relationship between sheet metal portions 71, 72 (about compound cuvature zone 73 for the container multi-layer folds) is increased, as shown, while leaving access for scoring tool 86 to form the peripheral scoreline in single-layer metal portion 74. A back scoreline means such as back scoreline 39 (or the back scoreline 52 of FIG. 11) is formed by tool 87, with the support for all scoring being provided by tooling 88. The sheet metal layers which will remain on the severed disc were prefolded as shown in FIG. 22 which leaves access for that portion of bucking up (backing) tool 88 (FIG. 23) for scoring; such access past the compound curvilinear zone 78 facilitates accurate depth scoring. As taught herein, variations in flat rolled sheet metal thickness (which are acceptable within normal gage tolerances) do not provide for sufficiently accurate depth scoring when trying to carry out scoring when working with more than one layer of the metal. Therefore, providing tooling access for single sheet metal layer scoring after having previously carried ' out the maximum- angled preo ientation of metal fold layers while still providing for such access tooling are important contribu- tions of the invention. Note that, notwithstanding prefolding of both SUBSTITUTESHEET separate multi-layer folds to near-completion, access is provided for the scoring tool on the scoring surface of single layer metal portion 74 and, for back-up tooling on the remaining surface. Providing the prefolded angled relationship shown, enables a minor final orientation for the pair of multi-layer sheet metal folds contiguous to the centerline of the peripheral scoreline so that the - removal of the disc is not obstructed by the multi-layer metal fold remaining with the end closure structure. FIG. 24 shows completing the multi-layer folds for the disc and final shaping for rivet button 91; and, FIG. 25 shows riveting the tab opener to the disc using support tooling while completing a minor movement of the plurality of layers in the fold remaining with the end closure struc- ture for desired alignment with the peripheral scoreline and for directing the working end 33 toward such scoreline by .limiting radial translation of the fulcrum for lever action rupture of central portion 52. Back scoreline tool 87 (FIG. 23) is selected to establish desired back scoreline configuration (central portion and angled legs) for the desired embodiment; back scoreline scoring is carried out during the same work stroke as the peripheral scoring. As shown in FIG. 24, the plurality of sheet metal layers for shielding the disc are oriented with the rounded-edge zone 78 being oriented in a radially outward SUBSTITUTESHξET direction with a diameter substantially equal to the diameter of the centerline of the peripheral scoreline so as to be in shielding relationship to raw edge metal on the disc after severance by obstructing (i.e. restricting • direct) access to such raw edge material. During the sequence of FIG. 24, a final minor shaping to form rivet button 91, prior to forming the rivet, takes place and folding of the sheet metal layers for the disc is completed from the prefolded stage shown in FIG. 23. The maximum diameter for the periphery of rounded metal transition-zone 78 i is established; that diameter is contiguous, in- plan view to a projection (onto a plane which is transversely perpendicular to the longitudinal central axis of the container) of the centerline of peripheral scoreline 34. Such shielding means for the raw edge metal remaining on the disc is located on the product side of the end wall panel. In the final sequence of FIG. 25, tab opener (30, 51) is placed over rivet button 91. Bar 65 helps to support the tab opener horizontally for the rivet forming step carried out between tooling 92, 94. The sheet metal layers comprising the fold remaining with the container can be moved slightly, as shown, so that compound curva¬ ture transition zone 73 periphery diameter approximates that of the centerline of scoreline 34. In plan view the periphery of zone 73 is contiguous to a projection of such centerline of scoreline 34, so as to at least partially shield' he raw-edge of metal which will remain with the container from direct access when the peripheral scoreline is severed. Metal portions 71, 72 can be folded slightly during this stage to provide such desired shielding by zone 73 without obstructing removal of end wall panel 31; i.e., zone 73 does not extend radially inwardly beyond the centerline of the peripheral scoreline 34. The position of such multi-layer fold limits radial-direction movement of opener 30 so that the arcuate movement of working end 33 is directed inwardly in relation to - the container toward the peripheral scoreline. The multi-layer sheet metal fold shielding means remaining with the removable disc is disposed on the inner surface of the end wall panel. The rounded-edge transi¬ tion zone (73, 78) of each multi-layer fold at least « partially obstructs direct access to its respective raw edge residual metal after severance since each such rounded-edge transition zone of its respective multi-layer fold is contiguous to raw edge metal remaining after severance of the residual metal along the centerline of such peripheral scoreline. The approximate dimensional values presented in the following tables are representative for a -307 (3-7/16") diameter can end structure: sheet metal flat rolled steel coating tinplate or TFS with organic coating nominal thickness .008" - .010" blank diameter 4.225" peripheral scoreline 34 centerline diameter 3.1" residual scoreline metal thickness .002" - .0025" residual metal thickness of score legs 35, 36 (FIG. 3) .005" residual metal, scoreline legs 53, 54 (FIG. 11) .002" - .0025" length of chord-*57 (FIG. 11) . ' 75" curvilinear zone 75 (FIG. 21v) dia. 3.18" chuck wall 69 dia. (FIG. 21) 3.25" ■ chuck wall height .18" Axial dimension between center of chime seam metal and panel 31 FIG. 22 - - - .39" FIG. 25 -21" Rivet head (diameter) .25" The location of the rivet depends on the dimension values and location of the tab opener; typically t sharp-edge chisel point of the working end of the t opener- is located contiguous to the peripheral scoreli but in a manner that the rounded edge 73 shielding mea remaining with the container does not impede the arcuat movement, initial rupturing-action of the working end the opener. The spacing from the working end of the tab opener to the aperture for the rivet button then deter¬ mines the location for the rivet button.in the end wall panel; typically the center of the rivet would be 1.25", measuring radially, from the center of the end panel in the embodiment of FIG. 11. Typical thicknesses for flat rolled alluminum end closures would be .009" to .012" with residual metal thickness for scored severing lines of about .004" to .005". Tab openers of" the present invention are longitud¬ inally rigid. .They are not lanced or cut out in the vicinity of the rivet as.in that prior practice in which the handle end moved relative to a portion of the opener which was held stationary by the rivet. The longitudinal¬ ly rigid feature enables continuation of the lever action using .the chime metal as a fulcrum as described above. The tab opener is preferably free of a finger opening (as in FIG. 1) but can be provided with a ring-shaped opener (as in FIG. 12). Approximate dimensional values for the tab openers identified are set forth below: Tab Opener 30 (FIG. 1) sheet metal flat rolled steel nominal thickness .012" to .019" tyP e of coating tinplate, TFS or galvanized overall length 1.54" SHEET 33 maximum width 1.1" rivet opening - distance from working end .30" Tab Opener 51 (FIG. 12) sheet metal flat rolled steel nominal thickness .012" - .019" type of coating tinplate, TFS or galvanized overall length 1.36" maximum width .92" rivet opening -distance from working end .30" The thickness gage for the tab opener can vary with the length and reinforcing provided by edge rolling and metal profiling. The object when working with the starter segment 45 embodiment (FIG. 1) is to provide for from twelve (12) to fifteen (15) pounds of force to be applied to the handle end of the tab opener without permanent damage to the tab opener due to longitudinal bending or collapsing. With the smaller starter segment provided by the back scoreline means of FIG. 11, and resultant increased mechanical advantage, force requirements are decreased by about 60%. Typically, tab openers fabricated from aluminum would rely on flat rolled aluminum having a nominal thickness gage between .014" and .022". The fully-leveraged-opening cont ibutions of the invention rely on other features for interrupting and HEET limiting rupure of metal along the back scoreline legs; the importance thereof is more readily visualized by a back scoreline on the configuration shown in FIG. 11 in which the legs 53, 54 take on a substantially radial direction which would be likely, under other circumstan¬ ces, to cause starter segment 58 to be ripped entirely from the end wall panel 31. However, the multi-layer sheet metal fold provided radially interior of peripheral scoreline 34 serves the important function (in addition to its later shielding function) during the opening procedure of limiting ripping of starter segment sheet metal along the back scoreline legs. Such multi-layer fold also serves as a hinge-like unitary connection with the removable end wall disc during the continued lever action of the tab opener about the chime seam as a fulcrum. That is, in the back scoreline embodiment of FIGS. 11 and 13,- such removal force on the end wall panel is transferred through such plurality of sheet metal layers in such shielding means (see FIG. 17) around the periphery of the disc to be removed. These sheet metal layers also provide a fulcrum axis during at least a portion of the initial opening procedure when the working end of the opener is rupturing peripheral scoreline. Later, such sheet metal layers also maintain the opener with the removable disc throughout the remainder of the opening procedure and after the disc is removed from the end closure structure. The back scoreline means con iguration facilitates use of a non-lanced tab opener; initial sheet metal rupture is facilitated by the radially inwardly pointed configuration of the central portion of the back score- line. In order for the embossed opening instructions (FIG. 13, 15-20) to be unobstructed during opening procedures the index or forefinger must be used for initial lifting (FIG. 15) and swinging (FIG. 16) the handle end of the opener toward the user. The follow- through opening procedure (FIGS. 17-20) resulting from this orientation diminishes the effort, and the spillage risks, of the present method over what was previously available. While specific values, materials, and configurations have been shown for purposes of specifically describing embodiments of the invention, other values will be avail¬ able in the light of the above teachings; therefore, for purposes of determining the scope of the present invention reference should be had to the appended claims.

Claims: CLAIMS 1. Full-open, disc-removal convenience-feature sheet metal end closure structure, comprising a generally-planar circular-configuration end wall panel circumscribed by unitary chime seam metal for attaching the end wall closure structure to a cylindrical configuration container, such end wall panel being recessed axially inwardly of such a container in relation to such chime seam metal, a peripherally located scoreline of curvilinear ' configuration in plarf view of such end wall panel defining a removable disc to provide an opening in such end closure structure which facilitates full removal of container contents, an elongated, longitudinally-rigid, tab opener secured by a rivet to such removable disc with the longitudinal axis of such elongated tab opening being oriented diametrically of such end wall panel, such rivet being unitary with the sheet metal of such removable disc, such tab opener having a working end and a handle end at its longitudinally opposite ends, with such working end being disposed contiguous to a portion of such peripheral scoreline for initiating rupture thereof, such rivet being positioned symmetrically on a diameter of such end wall panel and being disposed SUBSTITUTE SHEET 26 longitudinally toward the working end of such opener along 27 its longitudinal axis, and 28 back scoreline means positioned in such removable 29 disc, 30 such back scoreline means including 31 a central portion partially circumscribing such 32 rivet and located generally radially inwardly with 33 relation to such rivet toward the center of such end 3 wall panel, and 35 a leg portion extending from each side of such 35 central portion toward an adjacent portion of such 37 . peripheral scoreline with the effective included 33 angle defined between such leg portions being no 39 greater than 180°, 40 such leg portions terminating prior to contact 41 with such peripherally located scoreline, 42 such central portion of the back scoreline means 43 being ruptured by Class II lever action upon initial 44 movement of such tab opener during which the handle end of 45 the tab opener moves in an arcuate direction externally 46 away from the end wall panel and such a container, 47 such leg portions of the back scoreline means 48 extending toward such peripherally located scoreline on 49 opposite sides in relation to such longitudinal axis of 50 the tab opener helping to establish a chord in transverse 51 relationship to such diametrical orientation of such tab TE SHEET 88/05407 38 opener's longitudinal axis, with the location and posi- tioning of such chord and such leg portions defining a starter segment which is a minor area portion of the removable disc, 5 such starter segment being moved from its original 7 position in the end wall panel during continuation of 3 opening procedures for such end wall structure after such 9 Class II initiation of rupture, Q such starter segment including a portion thereof, 1 between such chord and its subtending arc, which is turned 2 inwardly of such a container as such arcuate direction 3 movement of the handle end of such opener causes Class I 4 lever action rupture of a minor .portion of the peripheral- 5 ly located scoreline by the working end of such tab 6 opener, and such minor portion comprising the subtending 7 arc for such chord, 8 with continuing lever-action rupture of such periph- 9 erally located scoreline beyond such minor portion being 0 carried out as a part of continued arcuate direction 1 movement of such handle end of the elongated opener 2 through an arc in excess of ninety degrees which estab- 3 lishes contact of such tab opener with such chime seam 74 metal, η- such chime seam metal contact then acting as a 76 fulcrum location for such continued lever action severance 77 of the peripherally located scoreline in which such 78 working end of the elongated tab opener acts substantially 79 in an outwardly-oriented axial direction in relation to 80 such a container, 81 such lever action provided by continued arcuate 82 direction movement of such elongated tab opener about such 83 chime seam metal as a fulcrum comprising Class I lever 84 action which moves such removable disc in an axial 85 direction externally away from such a container to 85 continue rupture of such remainder of the peripherally 87 located scoreline. 2. The structure of claim 1 further including 2 raw edge . metal shielding means for shielding severed 3 residual metal of the peripherally located scoreline 4 metal, such shielding means comprising 5 a pluality of layers of end wall panel sheet metal, 6 folded in overlying relationship, peripherally circu - 7 scribing such removable disc contiguous to such peripheral 8 scoreline, 9 such multi-layer sheet metal fold presenting a rounded-edge metal portion of circular configuration in plan view of such removable disc having a circumference substantially equal to the diameter of the centerline of such peripheral scoreline so as to be in contiguous relationship to such raw edge metal of such peripheral scoreline after severance thereof, such rounded-edge metal shielding such raw edge metal by restricting direct access to such raw edge residual scoreline metal during and after ET 88/05407 40 8 removal of such disc. 3. The structure of claim 2 in which 2. such back scoreline means leg portions define -an axis 3 of rotation for such tab opener which determines location 4 of such working end of such tab opener in relation to such 5 peripheral scoreline for initiating rupture thereof. 1 4. The structure of claim 2 further including 2 raw edge shielding means for shielding severed 3 residual metal of the peripherally located scoreline 4 remaining with such end closure structure associated with 5 such a container, comprising 6 a plurality of layers of end wall panel sheet metal, 7 folded in overlaying- relationship, located radially 8 outboard of ' and contiguous to such circular configuration 9 peripheral scoreline, 0 such multi-layer fold of sheet metal for shielding I raw edge metal remaining with such end closure structure 2 upon removal of such end panel disc presenting, in a plan 3 view of such end closure structure, a rounded-edge 4 transition zone portion of such multi-layer fold, having a 5 circumference about equal to, without being substantially 16 less than, that of the centerline of such peripherally 17 located scorelilne, which rounded protruding edge is 18 directed radially inwardly of such end wall structure so 19 as to be in contiguous relationship to such raw edge 20 metal about such opened container remaining upon severance SHEET of such peripherally located scoreline and removal of such circular disc, so as to shield such raw edge metal by at least partially obstructing direct access thereto after opening. 5. The structure of claim 2 in which such multi- layer fold of end wall sheet metal on such removable disc is disposed on the interior surface of such end closure structure in relation to such a container. 6. The structure of claim 4 in which such multi- layer fold of end wall sheet metal remaining with such end closure structure is disposed on the exterior surface of such end closure structure in relation to such a con- tainer. 7. The structure of claim 6 in which such multi-layer fold of sheet metal, for shielding raw edge metal remaining with such end closure structure, disposed on the exterior surface of such end closure structure restricts radial direction movement of such tab opener to direct its working end inwardly in relation to such container toward such peripheral scoreline for rupturing thereof. 8. The structure of claim 1, further including raw edge metal shielding means for shielding residual scoreline metal subsequent to rupture of such peripheral scoreline, such edge shielding means including BSTITUTE SH ET a pair of multi-layer folds of end wall panel sheet metal, one each of such pair of multi-layer folds of sheet metal being located on opposite surfaces of such end closure structure in relation to such a container, each of such pair of multi-layer folds of metal presenting a rounded-edge transition zone portion having a diameter approximately equal to that of the centerline of such peripheral scoreline so as to provide for shielding, respectively, the residual raw edge metal about such removable disc and* about such end closure structure opening on such a container, by at least partially obstructing direct access to such residual metal raw edges subsequent to severing along such centerline • of the peripherally located scoreline. 9. The structure of claim 8 in which such back scoreline means center portion which partially circum- scribes such rivet includes a semi-pointed configuration portion which is non- concentric w.ith such " rivet to facilitate rupture by minimizing the portion of the back scoreline which must be ruptured to initiate opening, such non-concentric portion extending radially toward the center of such end wall panel along the diametrical orientation of such elongated opener so as to be ruptured upon such initial movement of such working end of .the tab E SHE T opener is still in generally overlaying relationship to such central portion of the back scoreline means. 10. The structure of claim 8 in which such leg portions of the back scoreline means extend from such central portion initially in a transverse relationship to the radially oriented longitudinal axis for such opener, and then extend with a major component of direction which is substantially parallel to such radial direction of such longitudinal axis toward closely adjacent portions of such peripherally located scoreline. 11. The structure of claim 10 in which such leg- portions of the back scoreline means terminate contiguous to such shielding means of folded layers of unitary sheet metal such that such folded layers of sheet metal about the periphery of such disc to be removed from the end wall structure prevent such starter segment defined by such back scoreline means from being severed from the remainder of such disc during such opening procedure. 12. The structure of claim 11 in which such longitudinally rigid tab opener, after being swung through such arc in excess of 90° as part of such initial rupturing procedure, contacts such chime seam at a location along the longitudinal length of such tab opener which is contiguous to the longitudinal location of such rivet along such length of the tab opener. HEET 13. The structure of claim 8 in which such end closure sheet metal comprises flat rolled steel having a nominal thickness of about .008" to about .010" with residual metal thickness along such peripheral and back scoreline means of about .002" to.0025", and such tab opener comprises flat rolled steel having a - gage between about .012" and about .019". 14. The structure of claim 1 in which such tab opener is longitudinally reinforced and presents a solid configuration handle end which is free of any finger aperture. 15. The structure of claim 1 in which 2 _ such end closure sheet metal comprises flat rolled 3. aluminum having a thickness gage of about .009" to about 4 .012" with residual metal thickness along such peripheral 5 and back scoreline means of about .004" to about .005", 6 and 7 such tab opener comprises aluminum having a thickness 8 gage of. about .014" to about .022". 1 16. Method for fabricating an easy-open, disc- 2 removal end closure structure for a cylindrical sidewall 3 configuration container from flat-rolled sheet metal so as 4 to provide shielding for residual raw. edge metal remaining 5 after severing .a circular-configuration peripheral 6 scoreline defining such disc for opening such container, 7 comprising ET 45 8 providing a substantially-planar flat-rolled sheet 9 metal blank, such sheet metal blank being symmetrically 0 disposed about a centrally located axis which is. perpen- 1 dicular to the plane of such blank, 2 forming chime seam metal about the periphery of such 3 sheet metal blank for attaching such end closure structure 4 to a cylindrical container, and 5 countersinking an end wall panel of such blank, 6 such end wall panel having inner and outer surfaces 7 in relation to such a container, such surfaces being 8 substantially planar,' 9 such end wall panel, as countersunk, being radially 0 inward of such chime seam metal and being disposed axially 1 toward the interioir of such a container from such chime 2 seam metal, 3 such end wall panel countersinking steps defining 4 a chuck wall of substantially cylindrical 5 configuration contiguous to and extending from such 6 chime seam metal in such axial direction toward the 7 interior of such a container, and 28 an intermediate configuration which is stepped 29 in radial cross section in extending between such 30 chuck wall and ' the countersunk end wall panel, 31 such stepped configuration including a plurality of 32 unitary sheet metal portions in angled relationship to 33. each other with a compound curvilinear transition zone STITUTE SH ET 5407 " 46 located at such chuck wall, between each pair of angled metal portions, and at such end wall panel, establishing an orientation which is substantially perpendicularly transverse to such central axis for a sheet metal portion located intermediate other angled sheet metal portions of the stepped configuration between such chuck wall and the countersunk end wall panel, such intermediate sheet metal portion being estab- lished for locating a circular-configuration scoreline for defining the periphery of a disc to be removed from such end closure structure", with such remaining angled sheet metal portions being located radially inwardly and radially outwardly of such intermediate sheet metal portion, orienting angled sheet metal portions located radially on each side of such intermediate sheet metal portion so as to be in acute-angled, overlaying, prefolded relationship to each other to provide for a pair of multi- layer folds of sheet metal, ' such prefolding orientation of such multi-layer folds of sheet metal being carried out to locate one each of such pair on opposite sides radially of a predetermined location for such circular-configuration peripheral " scoreline to be located on such intermediate sheet metal portion and on opposite surfaces of such end wall panel so as to allow access for a scoring tool on one surface and 0 access for a backing-support tool for such scoring on the 1 remaining surface of such intermediate sheet metal 2 .portion, then 3 forming such circular-configuration peripheral score- 4 line to substantially uniform depth in such intermediate 5 sheet- metal portion, 6 forming a back scoreline means simultaneously with 7 such peripheral scoreline, such back scoreline means 8 having a central portion, at least partially circumscrib- 9 ing such rivet button and being disposed radially inwardly Q thereof, and. a leg extending from such central portion on 1 each side of such rivet button, in the direction of such 2 peripheral .scoreline with the effective included angle 3 between the directions for such legs being less than 180°, 4 and 5 completing disposition of such angularly prefolded 6 sheet metal portions in relation to such peripheral 7 scoreline such that the compound-curvilinear transition- 8 zone metal forming part of each of such pair of multi- 9 layer sheet metal folds defines a circular con iguration 0 v/hich is contiguous in plan view on each such surface of i such end wall panel with the circular configuration 2 defined by the centerline of such peripheral scoreline. 1 17. The method of claim 16 in which 2 a rivet button is formed in such countersunk end wall 3 panel during fabrication of such multi-layer folds of 8/05407 48 4 sheet metal and an elongated, longitudinally-rigid tab c opener is secured to such end wall panel with its working 6 end contiguous to such peripheral scoreline using such 7 rivet button which is unitary with such end wall panel by 8 placing such tab opener having a rivet button opening 9 over such rivet button and forming such rivet button into 0 a rivet to make such opener integral with such end wall 1 panel. 1 18. The method of claim 16 in which 2 - such multi-layer sheet metal fold is located in plan 3 view to extend radially inwardly with respect to the 4 centerline of such circular-configuration scoreline on the 5 inner surface of such end wall panel, and 6 such scoring ' is carried out on the outer surface of 7 such intermediate sheet metal portion while supporting the 8 inner surface thereof. 1 19. The method of claim 17 in which 2 such elongated tab opener is secured to such end wall 3 panel with the central longitudinal axis of such tab opener being disposed to be coincident with a diameter of 5 such end wall panel, and further including 5 embossing written instructions for opening such 7 container into such end wall panel in symmetrical rela- .8 tionship to such diameter along which such tab opener is 9 secured with such embossing being positioned diametrically 10 opposite to the location for such tab opener, and s ^sτ- τυτε sHi?ET 11 with the lettering in such written instructions being 12 oriented so that the working end of such tab opener is 13 oriented in the direction ■ of the user so as to enable 14 normal reading of such written instructions with the 15 handle end of the tab opener being swung in an arcuate 5 direction toward such user, and being embossed in lines 17 which are concentric with the peripheral scoreline so as 18 to reguire continuance of such original orientation of the 19 can body and end closure during the- opening procedure in 20 order to avoid obstruction of such instructions by the 21 hand of such use-r as the opening procedure is being 22 carried out. 1 20. Method for fabricating a convenience-feature end 2 • closure structure for a cylindrical container from flat- 3 rolled sheet metal so as to facilitate orientation for 4 full opening of such container and to provide post-opening 5 shielding of residual raw edge metal along a circular- 6 configuration peripheral scoreline defining such full 7 opening, comprising 8 providing a substantially-planar, circular-periphery 9 flat-rolled sheet metal blank of predetermined diameter, 10 - forming chime seam metal about the periphery of such . sheet metal blank for attaching such end closure structure 12 to a cylindrical container, 13 axially countersinking an end wall panel of such 14 blank which is circumscribed by such chime seam metal, 15 such countersinking positioning such end wall panel 88/05407 50 6 axially toward the interior of such a container from such 7 chime seam metal with inner and outer surfaces of such end 8 wall panel being substantiallly planar, 9 such countersinking defining 0 a chuck wall of substantially cylindrical 1 configuration contiguous to and extending from such 22 chime seam metal in such axial direction toward the 23 interior of such a container, and 24 a configuration which is stepped in radial cross 25 section with a plurality of angled sheet metal 26 portions interconnected by compound curved transition 27 zones between such chuck wall and the countersunk end 23 wall panel, 29 establishing a location for a scoreline of circular 30 configuration in plan view of such end wall for defining 31 the periphery of such disc to be removed from such end 32 wall structure, 33 such circular-configuration, peripheral scoreline to 34 be located in uniformly spaced relationship to and 35 radially inwardly of chime seam metal, 36 pre-folding such angled sheet metal portions for 7 orienting compound curved transition zones contiguous to 38 the location for such circular-configuration scoreline, 39. pre-forming a rivet button in such end wall panel 40 during fabrication of such pre-folded sheet metal por- 41 tions, such rivet button being located symmetrically with relation to a diameter of such end wall panel and disposed in predeterminedly spaced, relationship from such periph- eral scoreline and disposed toward one longitudinal end of such diameter, forming such circular-configuration, disc-periphery scoreline to substantially uniform depth by scoring a single layer of such sheet metal at such pre-established location for such scoreline while such sheet metal is being supported at its remaining surface opposite to the. surface being scored,-- completing disposition of such angularly-folded sheet metal portions in relation to such scoreline to position a rounded edge metal transition-zone forming part of each of such multi-layer folds of metal contiguous to such score- line on each such surface of such end wall panel, embossing written opening instructions into such end wall panel symmet ically with such diameter passing through such rivet button, such instructions being located at the opposite longitudinal end of such diameter in relation to such rivet button and being oriented so that in order to permit normal reading the rivet button is disposed in the direction of the user, attaching a longitudinally-rigid tab opener to such end wall panel using such rivet button with the central longitudinal axis of such tab opener being coincident with such diameter, the working end of such tab opener being contiguous to such peripheral scoreline and being disposed in the direction of the user such that to be able to read such opening instructions unobstructed by the user's hand, the index and/or middle finger ' of the user must be placed under the handle end of such opener to initiate and control opening in accordance with such embossed instruc- tions in which the handle end of the tab opener is moved in an arcuate direction toward the user. SUBSTITUTE SHEET

Inventors: BRAY JAMES A, DALRYMPLE WILLIAM H, MEERDO ROBERT, SAUNDERS WILLIAM T, BRAY, JAMES, A., DALRYMPLE, WILLIAM, H., MEERDO, ROBERT, SAUNDERS, WILLIAM, T.
Applicants: WEIRTON STEEL CORP, WEIRTON STEEL CORPORATION
Application year: 1987
Main classification: B65D17
IPC codes: B21D51, B65D17