This application is a continuation-in-part and claims priority of U.S. patent application Serial No. 07/147,267, filed January 22, 1988, which was a continuation-in-part and claimed priority of Interna- tional Application Serial No. PCT/US87/03418 , filed

December 23, 1987 which was a continuation-in-part and claimed priority of International Application Serial No. PCT/US87/02649, filed September 29, 1987 which was a continuation-in-part and claimed priority of International Application No. PCT/US87/00102 , filed January 23, 1987.

This invention relates to end closure structure providing abuse-resistance in combination with controlled opening of a full-panel convenience-feature along with raw-edge metal shielding during and subsequent to opening; and, is concerned with methods and apparatus for fabrication of such closure struc¬ tures in addition to opening methods.

In particular, this invention is concerned with providing a full-panel, convenience-feature end closure made from steel which can be readily opened while also providing shielding for raw edge residual scoreline metal to provide an improved type of

protection not previously available in such full-panel easy-open art. In addition, this invention is concerned with providing increased strength for sheet metal easy-open end closures for protection against abuse during transportation, warehouse stacking and market handling.

The above and other contributions are considered in more detail in describing embodiments of the present invention shown in the accompanying drawings. In such drawings:

FIG. 1 is a plan view of the exterior (public side) of an end closure structure embodying the invention;

FIG. 2 is a plan view from the interior (content side) of the end closure of FIG. 1;

FIGS. 3 and 4 are radial cross sectional views of the end closure structure of FIG. 1 along lines 3-3 and 4-4, respectively;

FIG. 5 is an enlarged view of a portion of the radial cross sectional view of FIG. 3 at a location diametrically opposite to the position of an integral opener for such end closure;

FIG. 6 is an enlarged cross section schematic view of a portion of an end wall panel for purposes of describing interrelated placement of portions of an end closure structure for operation of the working end

of an integral opener as taught by the invention;

FIGS. 7-12 are cross-sectional views of tooling and end closure structure for purposes of describing sequential fabrication steps, in which: FIG. 7 shows results of a blank forming stage,

• FIG. 8 shows initial configuration formation of a shallow depth rivet button and a peripheral shock- absorbing bead,

FIG. 9 shows further forming of the rivet button and initiation of pre-folding of an inner multi-layer sheet metal fold for shielding residual torn metal remaining with a removable panel portion,

FIG. TO shows scoring of the end wall panel and initiation of pre-folding of an outer multi-layer sheet metal fold for shielding residual torn metal remaining with the container,

FIG. 11 shows completion of such multi-layer sheet metal folds and forming profiling in a panel portion, and FIG. 12 shows completing formation of the . rivet securing an opener to the end wall panel; and

FIGS. 13 through 17 are perspective views of the end closure embodiment of FIG. 1 and a portion of a container for describing the opening procedure taught by the present invention.

In any of the known prior art "disc pull-out"

ends, only a minor portion of the peripheral scoreline was ruptured by lever action. Such rupturing took place initially when the opener was lifted. There¬ after, the remainder of the peripheral scoreline was separated by pulling backwardly on the ring-pull of the opener. In general, such previously available disc pull-out ends were forced to rely on folding the removable disc over (onto itself) so that the residual metal along the remainder of the peripheral scoreline could be "torn," as the opener was pulled backwardly- diametrically across the center of the end wall after the initial rupture.

In general, most such full-panel easy-open ends have used "lanced" openers in which the handle end of the opener was free to be lifted away from the panel while a riveted portion of the opener remained coplanar with the panel as riveted. However, when a "vent scoreline" was used in certain prior "disc pull- out" end closures, a longitudinally-rigid (lance-free) opener was used to rupture the vent portion of the back scoreline and provide for movement of the ring- pull opener from a radially-recessed position which was required for chuck tooling access for chime seam formation. Features of the present invention maintain the removable disc substantially planar and rigid through-

out the opening procedure for the container. Also, the substantially rigid end wall panel provided contributes to the continuing lever-action opening features made available by the invention. And, an accurate interrelated positioning of parts facilitates ease of initial rupture of the high-strength abuse- resistant ends provided.

In the circular-con iguration embodiment of FIGS. 1-5, end closure structure 27, shown in plan view of its exterior (public side) in FIG. 1, and in plan view of its interior (content side) in FIG. 2, is formed with chime seam metal 28 around its circular periphe¬ ry. A longitudinally-rigid (non-lanced) opener 30 (FIG. 1) is secured to removable disc 31 by rivet 32. The working end 33 of the elongated integral opener 30 is positioned in contiguous relationship to a portion of peripheral scoreline 34; the latter, as shown and generally preferable, has a circular configuration in plan view and defines the removable disc 31 portion of the recessed end wall panel of closure structure 27.

The cross section views of FIGS. 3 and 4 are taken along the full diameter of FIG. 1; FIG. 5 is an enlarged cross sectional view of a portion of FIG. 3 diametrically opposite to the location of the working end 33 of opener 30. Peripheral scoreline 34 is spaced radially inwardly from chuck wall 35 toward the

central longitudinal axis for a container shown in later figures; such axis passes through the geometric center of the removable disc 31 and end closure structure 27. A curvilinear vent scoreline portion 36 (FIG. 2) of the back scoreline means partially circumscribes rivet 32. Such back scoreline means continues along legs 37, 38; with one each extending on opposite sides of the rivet with each having a major component of direction which is radial. As taught herein, the back scoreline means is arch-shaped in configuration as shown in the embodiment of FIG. 2 and later figures; the arch-shape provides an added safety feature improvement over the moustache shaped back scoreline configuration previously provided and described in prior application Serial No. 07/147,267, filed January 22, 1988.

In a preferred embodiment of the present inven¬ tion, a multi-layer fold of sheet metal is positioned on each cross-sectional side of peripheral scoreline 34 (FIG. 5). Each such multi-layer sheet-metal fold acts to shield the raw edge residual metal remaining after severing along a peripheral scoreline. A triple-layer fold of sheet metal, as described in more detail later herein, is adequate and is preferred to accomplish such purposes.

Triple-layer metal fold 40 (FIG. 6) remains with the severable portion 31 (disc shaped in the embodi¬ ment of FIGS. 1-5) upon and after severing along a peripheral scoreline 34. Triple-layer fold 42 _L which is positioned outwardly of the scoreline 34, and in accordance with a preferred embodiment of the inven¬ tion on the exterior surface (public side) of the end closure structure 27, remains with that portion of the end closure structure remaining with the container upon and after severing of scoreline 34.

The configuration and placement of the arch- shaped back scoreline means (as seen in FIG. 2 and later figures) , along with other parts of the end closure structure, play important roles in the interaction of unitary and integral portions which facilitate ease of opening. Tearing along leg portions 37, 38 of the back scoreline means, after rupture of the curvilinear vent portion 36 would ordinarily cause lance-free opener 30 to move outwardly (with a radially directed component of movement in the circular embodiment of FIGS. 1-5) . Part of the invention teaches positioning a formed, unitary portion of end wall metal to accurately control (by stopping) such movement of the opener and to direct the opening force of its working end 33 toward a location, within prescribed limits, which facilitates

initial rupture of the peripheral scoreline 34.

Positioning of the rounded-edge transition zone 44 of multi-layer fold 42 (FIG. 6 enlargement controls any movement of the opener 30 and directs the opening force of its working end 33 toward the peripheral scoreline 34.

The rounded transition zone metal 43 of the multi-layer fold 40 is positioned oppositely but contiguous to the location of the peripheral scoreline 34. In a circular embodiment, rounded transition zone metal 43 has a predetermined diameter (measured in the plane of the end wall) which approximates, but is less than, the diameter of the rounded-edge transition zone metal 44 of multi-layer sheet-metal fold 42. The apex of scoreline 34 (at which rupture occurs) can also approximate, but is less than the circumference of transition zone metal 44. These teachings avoid attempting to remove an end wall disc having a greater circumference than that of the metal at zone 44. Rounded metal 43 is positioned to shield the raw- edge residual metal remaining with disc 31 by at least partially obstructing access of such torn edge metal. The torn portion of the peripheral scoreline 34 (at the apex of the "V" shaped radial cross-sectional configuration of the scoreline) has a diameter which can be approximately equal to that of rounded edge

metal 43 of the transition zone for multi-layer fold 40 but, as pointed out immediately above, must be less than that of rounded edge metal 44 of the outer barrier-means multi-layer sheet metal fold 43; otherwise, edge 44 would block removal of a disc which presented metal of larger diameter.

There is a range for application of an initial rupturing force which, to facilitate ease of opening, particularly in opening a steel end closure, is measured in thousandths of an inch for typical consumer-size cans, such as a three-inch diameter can. This range takes into account an arcuate path movement for the working end of the opener and, the "V" shaped configuration, in cross section, of the peripheral scoreline. Controlling movement of the integral opener so as to guide its working end 33 to contact the end wall panel within an acceptable range, as taught herein, is carried out by positioning the multi-layer fold 42 so as to act as a barrier in which edge 44 stops radial movement of opener 30 and direct its working end 33 inwardly (in relation to a con¬ tainer) toward such peripheral scoreline 34 in the recessed end wall panel.

The scoreline 34 has a diameter (where rupture occurs) which approximates or is slightly greater than that of the transition zone metal 43 of multi-layer

folds 40. The open end of "V" shaped (in cross section) scoreline 34 is between about five and about ten thousandths of an inch in radial dimension. For example, scoring .006" deep with a scoring tool having a 50° included angle results in the open end of the "V" having a radial dimension of .0056"; and, scoring .009" deep with a scoring tool having a 60° included angle results in an open end having a radial dimension of .0104". The working end of the opener is turned inwardly toward the recessed end wall panel by preventing radial movement of such working tip of the opener in the plane of, or parallel to the plane of, the end -wall panel. The location of the barrier means, multi-layer fold 42 is selected to take into account the angled movement of the working end 33 toward scoreline 34.

By stopping the horizontal (radial) component of movement, the lever-action opening force is thus directed vertically downwardly toward the scoreline 34. In accordance with present teachings, the radial distance between rounded edge 43 (approximately the same location as center of scoreline 34) and the barrier location of rounded edge 44 can be in a range between about five and about twenty thousandths of an inch for an end wall closure structure for a three (300) to a three and seven-sixteenths (307) inch

diameter container in which the end wall comprises flat rolled steel of about .008" to .010" nominal thickness gage. By preventing radial movement of the opener beyond such range, its working end will be turned, toward the end wall panel into, or sufficient¬ ly adjacent to, the open end of the peripheral score¬ line to facilitate ease of opening.

Positioning the barrier-means edge metal 44 beyond the earlier designated range (closer to shock- absorbing bead 45 which is contiguous to chuck wall 35, FIG. 5) will diminish the ease of opening, if not make opening substantially impossible for a consumer of average strength.

Along with such interrelated positioning of parts, the new combination of steps taught provides in combination abuse resistance, controlled movement of the opener and shielding of raw edge metal features while still providing access and timing, during sequential fabrication steps, for efficient and effective peripheral scoreline and rivet button formation.

In FIG. 7, the sheet metal is blanked and an end panel 49, inboard of chuck wall 35, is countersunk in relation to chime metal 28. A peripheral rim 50 is formed contiguous to chuck wall 35 for subsequent formation of shock-absorber bead 45 (as shown in FIG.

5, the outboard leg of such "U" shaped bead is an extension of chuck wall 35). From rim 50 a series of sheet metal portions, riser 51, step 52 and riser 53, extend in stepped fashion to recessed panel 49 which has an extended-planar-surface area.

Such riser and step sheet metal portions are joined by transition zones 54, 55, 56 which are of compound-curvature in a circular configuration embodiment with each being curvilinear in radial cross section and also around its respective circumference in a plane which is perpendicularly transverse to the central longitudinal axis for a container to which the end closure structβtre is attached. Such steps and risers, along with the transition zones participate in formation of the double multi-layer sheet metal folds 40, 42 formed during the sequences of FIGS. 8-12. Rim 50 leads through zone 54 to riser 51, which leads through zone 55 to step 52. The latter leads through zone 56 to riser 53 which leads through zone 57 to portion 58 of the recessed end wall panel.

In carrying out the procedures of FIGS. 8-12, the timing of the shock-absorbing bead formation, rivet- button formation, the multi-layer folding action, and the extent to which multi-layer sheet metal pre-fold- ing is carried out prior to formation of the periph¬ eral scoreline _. 34, are important considerations along

13 ar with the timing of end wall profiling formation in relation to securing an integral opener.

The peripheral scoreline 34 for the removable disc 31 is to be disposed in the end wall panel 49

5 intermediate the pair of multi-layer folds (FIGS. 5,

6) each of which separately shield residual scoreline metal on the separated disc and on the container. The forming sequence procedure taught enables tooling

^; .:- access, between the multi-layer pre-folds on each

.c 10 surface of the end closure, to enable scoring of a

1 single thickness of sheet metal while the latter is i- supported on the remaining surface opposite to the

.:. ; scoring tool. . The forming of the shock absorbing ' . bead, pre-folding of the sheet metal layers and

15 preforming the rivet button prior to scoring, enables completing the folding action, around such periphery, with minimized movement of sheet metal folds being required after such scoring so as to substantially preclude premature damage to residual scoreline metal.

20 In the operation of FIG. 8, an initial rivet button configuration 60, having a broad-diameter shallow-dome shape in cross section, is formed. Also, the sheet metal of peripheral rim 50 is pre-formed into shock-absorber bead 45. Step portion 52 is

25 oriented horizontally as shown. Peripheral scoring

(34) will subsequently take place on such horizontally

oriented metal portion 52 of the end wall panel 49. Such horizontally-oriented metal portion 52 is to be located so as to interconnect the pair of multi-layer folds 40, 42. Shock-absorbing bead formation, the stages of multi-layer folding of the sheet metal, scoreline formation, the stages of rivet button formation, profiling ,_ riveting an opener- to the removable panel portion, and embossing opening instructions are coordinated while optimizing the number of sequential steps. In addition to the above enumerated advantages of scoring a single layer of metal and avoiding premature damage to residual scoreline metal, the rivet button formation and riveting actions are carried out without interfering with the metal folding or scoring operations. Embossing opening instructions can be carried out simultaneously with formation of the rivet button and the profiling including recessed finger access, as described later herein. The shock-absorbing bead (45) as initially pre¬ formed (FIG. 8) is loosely defined. Also, start of the movement of metal, including transition zone 54 and a portion of riser 51, which will comprise a part of the outer multi-layer fold, is taking place. In FIG. 9, a smaller-diameter, greater-depth rivet button 62 is formed and the pre-folding of metal

portions for the inner multi-layer fold (40), that is riser portion 53 and a portion 58 of the end wall panel 49 contiguous to transition zone metal 57, are initiated. In FIG. 10, the sheet metal portion 54 of FIG. 9, along with a portion of riser 51 are moved so as to partially form the outboard multi-layer sheet metal fold (42) while leaving access for scoring tool 64 to form peripheral scoreline 34 in the exterior (public) surface of the end wall panel 49 (thus defining the removable portion 31); while on the interior (content) surface of the end closure back-up tool 65 has access past the inboard multi-layer fold (40) which is being formed. In FIG. 11, the peripherally-located shock- absorbing bead 45 is better defined in a portion of peripheral rim 50 by tool 66; and the outboard multi¬ layer fold is better shaped by tool 67 which tool helps to define the location of the radially-inwardly oriented transition zone metal (44 of FIG. 6). Tool 68 also helps to locate such transition zone 44 while tool 70 helps to position transition zone 43 (of fold 40 in FIG. 6) as the multi-layer folds are being formed in final orientation. The shape of the rivet button 62 is held by the tooling shown; and end wall panel profiling is being carried out.

In FIG. 12, while maintaining the shock-absorbing bead 45 and protecting sheet metal folds 40, 42, the rivet button of FIG. 11, after receiving opener 30, is formed into rivet 32. The registration and stacking protrusions 70, 72 (FIG. 1) are formed in the initial blanking stage. The profile risers 76, 78 and finger indentation 80, to improve finger access beneath handle end 82 of opener 30, are formed in a subsequent sequence, prior to placement of the opener 30 for riveting, along with embossing of opening instructions 84.

Profile risers 76, 78 serve the function of holding the non-lanced opener 30 substantially parallel to the generally planar configuration of the end wall panel 49 for riveting. Such risers and the finger indentation 80 are formed in the centrally located recessed profile 74 of the end wall panel 49.

Back scoreline formation preferably takes place during formation of peripheral scoreline 34. The arch-shaped back scoreline configuration of FIG. 2 which provides a chord of about 0.05" length between legs 37, 38 is preferred. This pre-selected chord length and the arch-shape segment defined by the back scoreline prevents any raw edge portion of the segment from extending over the side of the chime seam, thus preventing a hazard to safety. The pre-selected half-

inch chord length is also the approximate width of opener 30 at that location.

As referred to briefly earlier, upon initial lifting of the handle end of opener 30 (FIG. 13) in an arcuate direction externally away from the end closure, the vent portion 36 of the back scoreline ruptures relying on Class II lever action. With continuing arcuate movement, the back scoreline legs 37, 38 rupture toward the adjacent inner multi-layer sheet metal fold 40. The opener 30, with an endwall portion partially defined by the back score¬ line, pivots about the chord defined by the intersec¬ tion's back scoreline legs 37, 38 at 88 and 90 (FIG. 15) . The arcuate direction movement of the handle end of the opener 30 is continued in the same direction with the opener initially contacting (FIG. 14) chime 92 (formed from chime metal 28 and sidewall metal of container 94) which then acts as the fulcrum for Class I lever action opening, as the opener is swung over the side of container 94 (FIG. 15).

As indicated by FIG. 16, this "over the side" arcuate movement continues rupture of a significant major portion of peripheral scoreline 34 by Class I lever action about chime 92 as fulcrum. It should be noted in relation to FIG. 16, that none of the

segments of the disc defined by the arch-shaped scoreline extends over the side of the container, as occurred with corner portions of such segment when formed from a moustache-shaped scoreline as previously provided. This arch-shaped scoreline has a prese¬ lected chord length as shown (between 88, 90) which is no greater than the width of the opener at such location overlying such chord; such preselected chord length (about 0.50") can be maintained for differing sized containers.

After such peripheral scoreline rupture, the removable disc is lifted from container 94 as shown in FIG. 17.

In a typical end closure structure for a three and 7/16 inch diameter (307) can body side wall made from flat rolled steel (75 #/66, about .008" nominal thickness gage) metal plated and coated with a standard organic coating, the following data are representative :

Item Diameter

Chime metal 28 (C.L.) 3.50" Chuck Wall 35 3.25" Bead 45 (C.L.) 3.22"

Transition zone 44 (ref.) 3.078" Scoreline 34 (C.L.) 3.068" Transition zone 43 (ref.) 3.064" Rivet 32 (C.L.) 2.443 Other representative dimensions Item Dimensions

Bead 45 (depth) .035" (width) .050"

Chime metal 28

(Center Height above bottom of bead 45) .150"

Rivet 32

(head diameter) .250"

(body diameter) .166"

Chord length

(between legs 37, 38 at intersections 88, 90) 0.50"

Profiling panel 74

(diameter) 2.00"

Axial dimension between center of chime seam metal 28 and panel 49

(FIG. 7) .390

Typical thicknesses for flat rolled aluminum end closures would be .009" to .012" with residual metal thickness for scored severing lines of about .004" to

.005".

While specific values, materials, and configura¬ tions have been shown for purposes of specifically describing an embodiment of the invention, other values will be available in the light of the above teachings; therefore, for purposes of determining the scope of the present invention reference should be made to the appended claims.