Apparatus and Method for Redrawing a Cup with a Reformed Bottom

Abstract

An apparatus and method of forming a metallic cup that is subsequently reformed into a container body is provided. More specifically, the present invention relates to an apparatus and methods used to form a metallic cup with a reformed bottom having an inwardly oriented projection. The inwardly oriented projection reduces a height of the metallic cup but utilizes the same amount of metallic stock material as a taller cup with substantially the same diameter that does not have an inward projection. The inwardly oriented projection thus allows the use of a conventional bodymaker and other can manufacturing tools to convert the cup into a container body of a preferred size and shape.

Claims

1. A metallic cup with an inwardly oriented projection, comprising: an exterior sidewall with a first height and a first diameter; a closed end-wall interconnected to the exterior sidewall by a first radius; and the inwardly oriented projection having a projection sidewall interconnected to the closed end-wall by a second radius and a projection end-wall interconnected to the projection sidewall by a third radius, the projection end-wall oriented substantially parallel to the closed end-wall, wherein the inwardly oriented projection has a depth that is between about 5 percent and about 100 percent of the first height of the exterior sidewall.

2. The metallic cup of claim 1, wherein the projection sidewall of the inwardly oriented projection has an outer-most diameter that is not greater than seven-eighths of the first diameter of the exterior sidewall.

3. The metallic cup of claim 1, wherein the depth of the inwardly oriented projection is between about 0.1 inches and about 2.5 inches.

4. The metallic cup of claim 1, wherein the depth of the inwardly oriented projection is at least equal to the first diameter divided by an inner-most diameter of the projection sidewall multiplied by a starting height of the exterior sidewall before the inwardly oriented projection is formed minus the first height of the exterior sidewall of the metallic cup with the inwardly oriented projection.

5. The metallic cup of claim 1, wherein the metallic cup is formed of a metallic material with a predetermined thickness that is substantially uniform.

6. The metallic cup of claim 1, wherein an inner-most diameter of the projection sidewall is not more than an outer-most diameter of the projection sidewall minus six times a material thickness of the metallic cup.

7. The metallic cup of claim 1, wherein an inner-most diameter of the projection sidewall is not more than seven-eighths of the first diameter of the exterior sidewall reduced by six times a material thickness of the metallic cup.

8. The metallic cup of claim 1, wherein each of the second radius and the third radius are not less than four times a material thickness of the metallic cup.

9. The metallic cup of claim 1, wherein the inwardly oriented projection has a frustoconical cross-section.

10. The metallic cup of claim 1, wherein the projection end-wall has a maximum diameter extending to an inner-most edge of the third radius, the maximum diameter being between about 25 percent and about 60 percent of the first diameter of the exterior sidewall.

11. The metallic cup of claim 1, wherein the projection end-wall has a maximum diameter extending to an inner-most edge of the third radius, the maximum diameter being between about 1.1 inches and about 2.1 inches.

12. The metallic cup of claim 1, wherein the projection sidewall is oriented at an angle of between about 95 and about 158 with respect to the closed end-wall.

13. The metallic cup of claim 1, wherein the projection sidewall of the inwardly oriented projection has an outer-most diameter that is at least about 30 percent of the first diameter of the exterior sidewall.

14. An apparatus adapted to form a metallic container with an extended sidewall by redrawing a metallic cup with an inwardly oriented projection, comprising: a pressure sleeve to clamp the metallic cup in a predetermined alignment with a redraw die, wherein the metallic cup includes an exterior sidewall interconnected to a closed end-wall by a first radius, the inwardly oriented projection comprising: a projection sidewall interconnected to the closed end-wall by a second radius which has an outer-most diameter; and a projection end-wall interconnected to the projection sidewall by a third radius, wherein the inwardly oriented projection has a maximum depth that is between about 5 percent and about 100 percent of a first height of the exterior sidewall of the metallic cup; the redraw die including an aperture with an aperture diameter, wherein the aperture diameter is less than the outer-most diameter of the second radius; a ram; and a punch interconnected to the ram, the punch aligned substantially concentrically with the redraw die aperture, wherein when the ram advances toward the redraw die, the punch applies a force to the metallic cup to reverse the inwardly oriented projection and re-draw the metallic cup through the redraw die aperture to extend the first height of the exterior sidewall.

15. The apparatus of claim 14, wherein the aperture diameter of the redraw die is at least equal to the outer-most diameter of the second radius minus two times the second radius.

16. The apparatus of claim 14, wherein the redraw die aperture has a fourth radius with a redraw radius outer diameter, the outer-most diameter of the second radius being less than or equal to the redraw radius outer diameter plus two times the second radius and reduced by two times the fourth radius.

17. A method of redrawing a metallic cup having an inwardly oriented projection to form a metallic container with an extended sidewall, comprising: providing the metallic cup, including: an exterior sidewall with a first diameter and a first length; a closed end-wall interconnected to a lower end of the exterior sidewall by a first radius; and the inwardly oriented projection having a projection sidewall interconnected to the closed end-wall by a second radius and a projection end-wall interconnected to the projection sidewall by a third radius; clamping the closed end-wall of the metallic cup in a redraw apparatus with the closed end-wall proximate to a redraw die of the redraw apparatus, the redraw die including an aperture with a diameter that is less than an outer-most diameter of the second radius; and advancing a punch of the redraw apparatus toward the redraw die such that the punch applies a force to the metallic cup to extend the inwardly oriented projection in an opposite direction and re-draw the metallic cup through the redraw die aperture, wherein the first length of the exterior sidewall is extended by at least about 30 percent.

18. The method of claim 17, wherein an outer-most diameter of the projection sidewall of the inwardly oriented projection is not greater than seven-eighths of the first diameter of the metallic cup exterior sidewall.

19. The method of claim 17, wherein the redraw die aperture has a fourth radius with a redraw radius outer diameter that is at least equal to the outer-most diameter of the second radius plus two times the fourth radius reduced by two times the second radius.

20. The method of claim 17, wherein the diameter of the redraw die aperture is greater than or equal to the outer-most diameter of the second radius reduced by two times the second radius.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0051] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the invention and together with the Summary of the Invention given above and the Detailed Description of the drawings given below serve to explain the principles of these embodiments. In certain instances, details that are not necessary for an understanding of the disclosure or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein. Additionally, it should be understood that the drawings are not necessarily to scale.

[0052] FIGS. 1A-1E depict a prior art method and apparatus used to form a metallic cup;

[0053] FIGS. 2A-2F depict a method and apparatus for forming a cup with an inwardly oriented projection in a closed end-wall portion with a draw-redraw apparatus according to one embodiment of the present invention as well as a cup with an inward projection formed by the apparatus;

[0054] FIGS. 3A-3F depict a method and apparatus for forming a cup with an inwardly oriented projection in a closed end-wall portion with a draw-redraw apparatus according to another embodiment of the present invention as well as a metallic cup with an inward projection formed by the apparatus;

[0055] FIG. 4A is a bottom plan view of a metallic cup with an inwardly oriented projection in a closed end-wall portion according to one embodiment of the present invention;

[0056] FIG. 4B is a cross-sectional front elevation view of the metallic cup of FIG. 4A taken along line 4B-4B of FIG. 4A;

[0057] FIG. 4C is a detailed cross-sectional front elevation view of a portion of the closed end-wall and inwardly oriented projection of the metallic cup of FIG. 4B;

[0058] FIG. 5A is a cross-sectional front elevation view of a bodymaker depicting one embodiment of the present invention and illustrating the metallic cup of FIG. 4A clamped against a redraw die of the bodymaker;

[0059] FIG. 5B is another cross-sectional front elevation view of the bodymaker and metallic cup of FIG. 5A illustrating a punch of the bodymaker advancing towards the redraw die and with the geometry of the metallic cup during the forming stage illustrated separately to the left of the bodymaker for clarity;

[0060] FIG. 5C is another cross-sectional front elevation view similar to FIG. 5B illustrating the bodymaker advancing during reversal of the metallic cup projection and separately illustrating the geometry of the metallic cup during the forming stage for clarity;

[0061] FIG. 5D is yet another cross-sectional front elevation view similar to FIG. 5B illustrating the bodymaker when the metallic cup projection has been fully reversed, the geometry of the metallic cup being illustrated separately for clarity to the left of the bodymaker; and

[0062] FIG. 5E is a cross-sectional front elevation view of the bodymaker and the metallic cup of FIG. 5A in which the bodymaker has completed a draw operation on the metallic cup to reduce the diameter of the metallic cup and increase the sidewall height and with the redrawn metallic cup illustrated separately for clarity.

[0063] Similar components and/or features may have the same reference number. Components of the same type may be distinguished by a letter following the reference number. If only the reference number is used, the description is applicable to any one of the similar components having the same reference number.

[0064] To assist in the understanding of one embodiment of the present invention the following list of components and associated numbering found in the drawings is provided herein:

TABLE-US-00001 Number Component 2 Draw-redraw apparatus; 4 Sheet of metallic stock material 6 Blank and draw die 8 Blank 9 Cup 10 Sidewall 11 Closed end-wall 12 Redraw die 13 Formed cup 14 Closed end-wall 15 Sidewall 16 Draw-redraw apparatus 18 Blanking die 20 Cut edge 22 Blank and draw die 24 Draw pressure pad 26 Redraw pressure pad 28 Redraw die 29 Void between blank and draw die and redraw die 30 Die center punch 31 Cavity of die center punch 32 Reform draw pad 33 Cavity of reform draw pad 34 Reform punch 35 Extension of reform punch 36 Leading surface of blank and draw die 37 Leading edge 38 Blank 40 Cup 41 Closed endwall 42 Redrawn cup 43 Sidewalls 44 Projection 45 Open end 46 Finished cup with reformed closed end-wall 47 Longitudinal axis 48 Diameter of blank 50 First sidewall height 52 First diameter of end-wall 54 Second sidewall height 56 Second diameter of end-wall 58 Third sidewall height 60 Third diameter of end-wall 62 Projection height or depth 64 Projection diameter 65 Reference axis 66 Projection sidewall 67 Angle of projection sidewall 68 Projection end-wall 70 Bodymaker 72 Punch 74 Ram 76 Pressure sleeve 78 Redraw die 79 Redraw die aperture 80 Punch bolt 82 Punch face distance to die face 84 Redrawn cup 86 Closed end-wall 88 Sidewall portion T Metal Thickness H Height of metallic cup with projection H.sub.o Height of metallic cup without projection D1 Diameter of metallic cup D2 Projection sidewall outer diameter D3 Projection sidewall inner diameter D4 Diameter of projection outer radius D5 Redraw die diameter D6 Diameter of redraw radius D7 Bodymaker punch diameter D8 Diameter of projection end-wall R1 Outer radius of metallic cup nose R2 Projection outer radius R3 Projection inner radius R4 Redraw radius S Projection depth

DETAILED DESCRIPTION

[0065] The present invention has significant benefits across a broad spectrum of endeavors. It is the Applicant's intent that this specification and the claims appended hereto be accorded a breadth in keeping with the scope and spirit of the invention being disclosed despite what might appear to be limiting language imposed by the requirements of referring to the specific examples disclosed. To acquaint persons skilled in the pertinent arts most closely related to the present invention, a preferred embodiment that illustrates the best mode now contemplated for putting the invention into practice is described herein by, and with reference to, the annexed drawings that form a part of the specification. The exemplary embodiment is described in detail without attempting to describe all of the various forms and modifications in which the invention might be embodied. As such, the embodiments described herein are illustrative, and as will become apparent to those skilled in the arts, may be modified in numerous ways within the scope and spirit of the invention.

[0066] Although the following text sets forth a detailed description of numerous different embodiments, it should be understood that the detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims. To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such claim term by limited, by implication or otherwise, to that single meaning.

[0067] Referring now to FIGS. 2A-2F, a draw-redraw apparatus 16 with a novel die set of one embodiment of the present invention is provided. The apparatus 16 generally comprises a blank die 18 with a cut edge 20, a blank and draw die 22, a draw pressure pad 24, a redraw pressure pad 26, a redraw die 28, a die center punch 30, a reform draw pad 32, and a reform punch 34. The apparatus 16 is operable to form a plurality of cups from a sheet 4 of metallic stock material through a draw and wall ironing (DWI) process. Optionally, the apparatus 16 may redraw the cups. The finished cups 46 are formed from a blank 38 with an increased diameter 48 and have an inwardly oriented projection 44 in a closed end-wall portion that reduces a height of the cup compared to cups formed from a similar sized blank using the prior art process illustrated in FIG. 1. Other forming operations may subsequently be used to form the cups into container bodies of any shape for any variety of products, including aerosol cans.

[0068] As illustrated in FIG. 2A, a sheet 4 of metallic stock material is fed into the apparatus 16. The blank and draw die 22 is then moved in a first direction toward the blanking die 18 and the draw pressure pad 24 until a leading surface 36 of the blank and draw die 22 contacts and applies pressure to an upper surface of the sheet 4. The sheet 4 is forced against the cut edge 20 of the blanking die 18, as illustrated in FIG. 2B. The sheet 4 is sheared to form a blank 38 of a predetermined size and shape. The blank 38 is also illustrated in FIG. 2B separated from the apparatus 16 for clarity. In one embodiment, the blank 38 has a generally circular shape with a predetermined diameter 48 of between about 5 inches and about 10 inches, and in some embodiments the diameter is more preferably between about 7 inches and about 8 inches. In other embodiments the blank diameter is between about 6.75 inches and about 8.25 inches to form smaller sized cups. However, it will be appreciated by those of skill in the art that the blank 38 can have any desired diameter depending upon the desired size of the finished container. Further, the blank may have any shape, including oval, square, rectangular, triangular, circular, and/or combinations thereof.

[0069] In conjunction with the movement of the blank and draw die 22 and the draw pressure pad 24, the redraw pressure pad 26 and the die center punch 30 are moved towards the redraw die 28. The bottom surface of the blank 38 is then contacted with the redraw die 28. The peripheral edge of the blank 38 is pushed in the first direction while a center portion of the blank is supported. The blank 38 is deformed, or drawn, under pressure and conforms to an interior surface of a hollow interior of the blank and draw die 22 forming a cup 40 with a predetermined, generally cylindrical shape. In an alternative embodiment, a projection 44 may be formed in the cup at this stage or later as described below.

[0070] The cup 40 generally includes an open end 45, a sidewall 43 with a first height 50, and a closed end-wall 41 with a first diameter 52, as illustrated in FIG. 2C. In one embodiment, the cup 40 has a generally cylindrical shape, although as will be appreciated by those of skill in the art, the cup 40 can have any desired shape, including a non-cylindrical shape. An exterior surface of the redraw die 28, which comprises a smaller outer diameter than the internal diameter of the hollow interior of the blank and draw die 22, is nested within the hollow interior of the blank and draw die 22. As the blank 38 is deformed, the blank 38 transitions out of a space between the blank and draw die 22 and the draw pressure pad 24.

[0071] Referring now to FIG. 2D, a portion of an upper surface of the cup 40 is contacted with the die center punch 30. Optionally, the cup 40 may be reformed (or partially redrawn) to form a redrawn cup 42 as the die center punch 30 continues to move in the first direction, conforming a portion of the cup 40 to the interior shape of the redraw die 28 under pressure. As illustrated in FIG. 2D, the material of the cup 40 is translated out from a space 29 between the blank and draw die 22 and the redraw die 28. While the cup is redrawn, the cup 40 also transitions out of a space between the redraw pressure pad 26 and the redraw die 28. The redrawn cup 42 in FIG. 2D has a closed end-wall 41 with a second diameter 56 that is less than the end-wall diameter 52 of the cup 40 shown in FIG. 2C. In one embodiment, the redrawn cup 42 has a diameter of between about 2.5 inches and about 5.0 inches and in another embodiment between about 3.5 inches and about 4.25 inches. For smaller cups, the diameter of the redrawn cup is between about 2.75 inches and 3.50 inches. The redrawn cup 42 illustrated in FIG. 2D has a sidewall 43 with a height 54 that may be the same as, or different from, the height 50 of the sidewall 43 of cup 40. As will be appreciated by one of skill in the art, the cup 40 may be reformed any number of times, including zero times. Each time the cup is reformed, the diameter of the closed end-wall is decrease by a predetermined amount.

[0072] A closed end-wall portion of the reformed redrawn cup 42 contacts the reform draw pad 32 and moves the reform draw pad 32 in the first direction toward the reform punch 34 as the die center punch 30 continues moving in the first direction forming the optional redrawn cup 42. An extension 35 of the reform punch 34 aligns substantially concentrically with a cavity 33 formed through the reform draw pad 32. In one embodiment, the extension 35 has a generally cylindrical shape with a tapered or rounded upper edge 37. However, it will be appreciated by those of skill in the art that the extension 35 can have any desired shape. In one embodiment, the extension has a cross-section with a round shape, an oval shape, a square shape, a rectangular shape, a triangular shape, a frustum, and/or combinations thereof.

[0073] The cavity 33 of the reform draw pad 32 has a shape adapted to at least partially receive the extension 35 of the reform punch 34. In one embodiment, the cavity 33 has a generally circular shape with an interior diameter of between about 2.0 inches and about 2.75 inches, and more preferably between about 1.5 inches and about 3.0 inches, which is greater than an exterior diameter of the extension 35. Thus, the interior diameter of the cavity 33 is between about 40% and about 75% of the diameter of the draw pad 32, and in other embodiments between about 50% and about 65% of the diameter of the cavity 33. As will be appreciated by those of skill in the art, the cavity 33 can have any desired shape adapted to at least partially receive the extension 35. In one embodiment, the cavity 33 is substantially centered on the reform draw pad 32. In another embodiment, the cavity has a shape that is different than the cross-sectional shape of the extension.

[0074] Referring now to FIG. 2E, as the die center punch 30 continues to move in the first direction to form the redrawn cup 42, the reform draw pad 32 also continues to move in the first direction. The extension 35 of the reform punch 34 projects at least partially through the cavity 33 and contacts the closed end-wall portion 41 of the redrawn cup 42. The extension 35 applies force to the closed end-wall 41 and reforms the closed end-wall, displacing the closed end-wall at least partially into a cavity 31 of the die center punch 30. The cavity 31 is adapted to at least partially receive the extension 35 and a portion of the closed end-wall of the redrawn cup 42. In one embodiment, the cavity 31 has a generally cylindrical shape and is substantially concentrically aligned with the cavity 33 of the reform draw pad 32. The cavity 31 has a diameter that is at least equal to the exterior diameter of the punch extension 35 plus two times the thickness of the material of the redrawn cup 42. Thus, the extension 35 pushes against an unsupported portion of the closed end-wall 41 of the cup 42. As the extension 35 pushes against an exterior surface of the end-wall, a portion of the interior surface of the closed end-wall is supported.

[0075] In one embodiment, the cavity 31 has an interior diameter that is at least equal to the interior diameter of the cavity 33 of the reform draw pad 32. In one embodiment, the cavity 31 has a diameter of between about 1.5 inches and about 3.0 inches, and alternatively between about 2.0 inches and about 2.75 inches. As the extension 35 applies force to the closed end-wall portion of the redrawn cup 42, the closed end-wall portion of the redrawn cup 42 is reformed and an inwardly oriented projection 44 is formed in a portion of the closed end-wall 41 of the finished cup 46. Although the inwardly oriented projection 44 is illustrated being formed on a redrawn cup 42, it will be appreciated that an inwardly oriented projection 44 can also be formed in a cup 40 that has not been reformed using the method and apparatus of the present invention.

[0076] As the extension 35 applies force to the metallic cup 46, the closed-end wall portion 41 of the metallic cup 46 is clamped between the die center punch 30 and the reform draw pad 32. However, the clamp surfaces are large and the clamp forces are relatively low. Accordingly, the metallic material of the closed end-wall portion 41 does not thin or stretch appreciably. In one embodiment, the closed-end wall portion 41 and the projection 44 have a substantially uniform thickness. The thickness of portions of the sidewall 43 may decrease and increase as a normal effect of drawing of the metallic cup. However, the tooling of the draw-redraw apparatus 16 is not designed to stretch or thin the metallic cup 46 during redraw or during formation of the projection 44.

[0077] The finished cup 46 illustrated in FIG. 2E has a closed end-wall 41 with a predetermined diameter 60 of between about 2.5 inches and about 5.0 inches and preferably between about 3.5 inches and about 4.25 inches. In one embodiment, the diameter 60 is substantially the same as the redrawn cup diameter 56 illustrated in FIG. 2D. The cup 46 has a sidewall 43 with a predetermined height 58 of between about 2.0 inches and about 5.0 inches and more preferably between about 2.5 inches and about 4.5 inches. The projection 44 has a predetermined height 62 of between about 0.25 inches and about 2.5 inches and more preferably between about 0.5 inches and about 1.25 inches. A diameter 64 of the projection 44 is between about 1.5 inches and about 3.0 inches. In a more preferred embodiment, the diameter is between about 2.0 inches and about 2.75 inches. Optionally, the projection diameter 64 is at least about 30 percent of the cup diameter 60.

[0078] The inwardly oriented projection 44 can have any desired size or shape. In one embodiment, the projection 44 has a cross-section of a truncated cone, or frustum, with a first diameter 64 proximate to the closed end-wall surface 41 of the finished cup 46 that is greater than a second diameter at a top, or closed end-wall, of the projection 44. In another embodiment, the projection 44 has a generally cylindrical shape with a substantially constant diameter. Thus, the volume of the cup 40 shown in FIG. 2C when compared to the cup 46 shown in FIG. 2E is reduced by between about 15% and about 50%. More preferably, the internal volume is reduced by between about 20% and about 45%. Of course, as will be appreciated, the size (or volume) of the projection 44 may be altered. Accordingly, the internal volume of the cup 46 may change. In one embodiment, the internal volume of cup 40 is reduced by between about 5% and about 15% when the projection 44 is formed to create cup 46. In a more preferred embodiment, the internal volume of cup 46 is about 10% less than cup 40. In another embodiment, the internal volume of cup 46 is at least 7% less than cup 40.

[0079] After forming the projection 44, the tooling is separated and/or extracted, and the finished cup 46 with the reformed bottom is ejected as illustrated in FIG. 2F. In one embodiment, the die center punch 30, reform draw pad 32, and the redraw pressure pad 26 each move in the second direction toward their starting positions illustrated in FIG. 2A. As the reform draw pad 32 moves in the second direction, the finished cup 46 moves out of the redraw die 28 until the bottom surface of the finished cup 46 is substantially level with the upper surface of the blanking die 18. The finished cup 46 is then ejected from the apparatus 16 and another portion of the sheet 4 of metallic stock material is fed into the apparatus 16, as illustrated in FIG. 2A. In one embodiment, the finished cup 46 is ejected laterally from the apparatus 16.

[0080] Referring now to FIGS. 3A-3F, a draw-redraw apparatus 16A according to another embodiment of the present invention is provided herein. Apparatus 16A is used to form a finished cup 46 with an inwardly oriented projection 44 in a number of sequential steps in a manner similar to the method illustrated in FIGS. 2A-2F. In apparatus 16A, a reform punch 34A is positioned further from the sheet 4 of metallic stock material with respect to the redraw die 28 compared to the position of the reform punch 34 of the embodiment of the present invention described in conjunction with FIG. 2. Thus, the optional redraw of the cup 40 to form the redrawn cup 42, illustrated in FIG. 3D, is substantially completed before the reform punch 34A reforms the closed end-wall portion of the redrawn cup 42, illustrated in FIG. 3E. In one embodiment, the reform punch 34A has substantially the same size and shape as reform punch 34.

[0081] Referring now to FIG. 3A, a sheet 4 of metallic stock material is fed into the apparatus 16A. A blank 38 with diameter 48 is sheared from the sheet 4 as illustrated in FIG. 3B. The blank 38 illustrated in FIG. 3B may be the same as, or similar to, blank 38 illustrated in FIG. 2B. Similarly, the diameter 48 may have the same, or similar, dimensions as discussed above in conjunction with FIG. 2B.

[0082] Referring now to FIG. 3C, the apparatus 16A forms the blank 38 into a cup 40 with a predetermined shape. The cup 40 may have the same shape, end-wall diameter 52, and sidewall height 50 as the cup 40 illustrated in FIG. 2C. Optionally, the cup 40 is redrawn to form a redrawn cup 42, as illustrated in FIG. 3D. The redrawn cup 42 illustrated in FIG. 3D may have the same end-wall diameter 56 as the redrawn cup 42 illustrated in FIG. 2D. However, in this embodiment of the present invention, the sidewall 43 is substantially completely re-drawn before the closed end-wall 41 is reformed. Accordingly, the redrawn cup 42 illustrated in FIG. 3D has a sidewall with a generally linear cross-sectional height 54 which is distinct from the shape and size of the sidewall of the cup 42 of the embodiment illustrated in FIG. 2D. In one embodiment, the height 54 of cup 42 illustrated in FIG. 3D is between about 2.0 inches and about 4.5 inches. More preferably, the height 54 is between about 2.5 inches and about 3.75 inches. As will be appreciated by one of skill in the art, in one embodiment, the cup 42 shown in FIG. 3D may be ejected from the apparatus 16A and used to form a container. Thus, in one embodiment, the cup 42 shown in FIG. 3D may be used to form a container with a predetermined shape and size without forming a projection in the closed end-wall of the cup.

[0083] The closed end-wall 41 of the redrawn cup 42 is reformed by the reform punch 34A to form a finished cup 46 with a reformed closed end-wall comprising an inwardly oriented projection 44, as illustrated in FIG. 3E. The height 58 of the cup 46 is less than the height 54 of cup 42 illustrated in FIG. 3D after forming the inwardly oriented projection 44. Thus, the total internal volume, or the overflow volume, of cup 42 is reduced. More specifically, the volume of the cup 46 shown in FIG. 3E is reduced with respect to the volume of the cup 42 shown in FIG. 3D by between about 5% to about 40%. In a more preferred embodiment, the volume of cup 46 is between about 10% and about 30% less than the internal volume of cup 42 illustrated in FIG. 3D. In another embodiment, the volume of cup 46 is between about 15% and about 21% less than the internal volume of cup 42 shown in FIG. 3D. In a still more preferred embodiment, the cup 46 has a volume that is about 18% less than the volume of cup 42 of FIG. 3D.

[0084] As will be appreciated by one of skill in the art, changing the size or shape of the projection 44 changes the relative volumes of cups 42 and 46. Thus, in still another embodiment of the present invention, the volume of cup 42 of FIG. 3D is reduced by at least 10% when the projection 44 is formed to make cup 46. The cup 46 and projection 44 illustrated in FIG. 3E may generally have the same shape and dimensions as the cup 46 projection 44 illustrated and described in conjunction with FIG. 2E, above. Thus, in one embodiment, the cup 46 has the same end-wall diameter 60, sidewall height 58, projection diameter 64, and projection height 62 as the cup 46 of the embodiment of the present invention illustrated in FIG. 2E.

[0085] Referring now to FIG. 3F, the finished cup 46 is ejected from the apparatus 16A. In one embodiment, the finished cup 46 is ejected laterally from the apparatus 16. The finished cup 46 is subsequently formed into a container body by a bodymaker by any method known to those of skill in the art as described further in conjunction with FIGS. 5A-5E.

[0086] In various embodiments, pneumatic compressed air or other means provides force to one or more of the tooling components of the draw-redraw apparatus 16 described herein. For example, in one embodiment, a tooling component, such as the redraw pressure pad 26 is provided with an inner air pressure which applies a clamping force as shown in FIGS. 2B-2D and 3B-3D and another tooling component, such as the draw pressure pad 24, is supplied with an outer air pressure, which is illustrated as a clamp force in FIGS. 2B and 3B.

[0087] By reforming the closed end-wall portion 41 of the finished cup 46 with the projection 44, the height 58 of the finished cup 46 is decreased compared to the height of the cup 13 formed by the prior art method. Accordingly, existing tooling and bodymakers can be used to form cups 46 into container bodies that are larger. In this manner, container bodies with an increased height and/or an increased diameter can be formed. The finished cup 46 has a height 58 that is less than the height of the formed cup 13 formed using the prior art method and apparatus, although the diameter 48 of the blanks 8, 38 used to form cups 13, 46 are substantially equal.

[0088] Further, reforming the closed end-wall portion of the finished cup 46 enables a shorter bodymaker ram stroke and a shorter stroke redraw carriage to be used when forming the container body. Thus, the bodymaker can operate at a higher speed than is possible when forming a container body from a cup 13 without the reformed closed end-wall having the inwardly oriented projection. As will be appreciated by one of skill in the art, the maximum amount that the diameter of a cup can be reduced by a bodymaker in a subsequent redraw step is known as a draw ratio. By forming an inwardly oriented projection 44 on a closed end-wall portion of a finished cup 46 with a diameter corresponding to the draw ratio of a bodymaker, the amount of the material in the finished cup 46 can be increased while the height 58 of the finished cup 46 is shortened. Thus, the finished cup 46 can be formed into a container body by a conventional bodymaker.

[0089] A further advantage of reforming the closed end-wall portion 41 of the finished cup 46 is that the finished cup 46 of a predetermined blank size and maximum height may be formed with a smaller transverse dimension of a longitudinal cross section than would otherwise be possible. For example, a cylindrical cup with a reformed closed end-wall and specified maximum height may have a smaller diameter than a cylindrical cup of the same height made from a blank of the same size. In one embodiment of the present invention, the diameter 60 of a finished cup 46 with a cylindrical shape having a reformed closed end-wall is approximately 5% less than that of a cylindrical cup 13 of the same height without an inwardly oriented projection 44, although both cups 13, 46 are formed from substantially the same size blank 8, 38. This reduction in the transverse dimension of the finished cup 46 facilitates the redraw operation in the bodymaker. The redraw operation in the bodymaker must reduce the internal diameter of the cylindrical cup to the diameter of the finished container body. Reduction of the cup diameter to the finished container body diameter is most reliably accomplished when the reduction in the diameter of the cup is small. If the attempted diameter reduction is too large, the redraw operation will fail by any of several means, including wrinkling or rupture of the cup material. In one embodiment, the reduction in diameter from cup diameter to container body diameter, as compared to the cup diameter, is limited to not more than 40%. In another embodiment, the reduction is limited to not more than 35%.

[0090] Referring now to FIGS. 4A-4C, one embodiment of a metallic cup 46 with an inwardly oriented projection 44 is illustrated. The metallic cup 46 can be utilized in a container bodymaker 70 (illustrated in FIG. 5) to manufacture an extended length container. In one embodiment, the metallic cup 46 may be formed by a draw-redraw apparatus 16, 16A or other metallic cup manufacturing processes known by those skilled in the art. As described above, when the projection 44 is formed, the metallic material of the metallic cup 46 does not thin or stretch appreciably. Accordingly, the metallic cup 46 has a metal thickness T that is substantially uniform. More specifically, the metal thickness T of the metallic cup 46 is substantially equal in each of the projection 44, the closed end-wall portion 41, and the sidewall 43. In another embodiment, the metal thickness T of at least the closed end-wall portion and the projection 44 are substantially equal. In one embodiment, the metal thickness T is between about 0.004 inches and about 0.028 inches. In another embodiment, the metal thickness T is between about 0.006 inches and about 0.024 inches. Optionally, the metal thickness T is between about 0.08 inches and about 0.18 inches in a more preferred embodiment.

[0091] The metallic cup 46 generally includes a first radius R1 between the closed end-wall portion 41 and the sidewall portion 43. A second radius R2 is formed between the closed end-wall portion 41 and a sidewall 66 of the projection 44. A third radius R3 is formed between the sidewall 66 and an end-wall 68 of the projection 44. Each radius R1, R2, and R3 is generally not less than four times the metal thickness T of the metallic cup 46, or

R1, R2, R34*T

[0092] In one embodiment, the projection sidewall 66 projects from the closed end-wall 41 at an oblique angle. In one preferred embodiment, the projection sidewall 66 begins at an interior portion of the second radius R2 a first distance from a longitudinal axis 47 of the metallic cup 46 and slopes inwardly toward the longitudinal axis 47 until reaching the third radius R3. Accordingly, and referring now to FIG. 4C, in one embodiment the projection sidewall 66 is formed at an angle 67 with respect to a reference axis 65 that is substantially perpendicular to the end-wall portion 41. In one embodiment, the sidewall angle 67 is between about 5 degrees and about 68 degrees. In another embodiment, the sidewall angle 67 is between about 10 degrees and about 16 degrees.

[0093] Referring now to FIG. 4B, the projection 44 reduces the sidewall height 58 (or H) of the metallic cup 46 compared to the larger sidewall height 54 (or H.sub.o) of a metallic cup 42 (illustrated in FIG. 3D) of the same diameter 60 without the projection 44. More specifically, as described above, the cup sidewall portion 43 is shortened as metal is drawn from the sidewall 43, across the closed end-wall portion 41, and into the projection 44 during formation of the projection, as illustrated in FIGS. 2E and 3E. Accordingly,

H<H.sub.o

[0094] In one embodiment, forming the inwardly oriented projection 44 decreases the height H.sub.o of the cylindrical sidewall 43 by at least about 3 percent. In another embodiment, the sidewall height H of the redrawn cup 46 with the projection 44 is between about 60 percent and about 97 percent of the sidewall height H.sub.o of the redrawn cup 42 without the projection 44.

[0095] The metallic cup 46 may have a diameter 60 (or D1) that varies depending on the size of a metallic container being manufactured. In one embodiment, the diameter 60 (D1) is between about 3.5 inches and about 4.3 inches, or between about 3.7 inches and about 4.1 inches. Alternatively, the diameter 60 (D1) is between about 3.9 inches and about 4.0 inches in a more preferred embodiment.

[0096] In one embodiment, an outer diameter D4 of the projection outer radius R2 is between about 2.1 inches and about 3.3 inches. In another embodiment, the outer diameter D4 is between about 2.5 inches and about 2.9 inches. Optionally, in a more preferred embodiment, the outer diameter D4 is between about 2.65 inches and about 2.75 inches. In one embodiment, the outer diameter D4 is at least about 30 percent of the metallic cup diameter 60 (or D1). In another embodiment, the outer diameter D4 is between about 48 percent and about 94 percent of the metallic cup diameter D1. Alternatively, in another embodiment, the outer diameter D4 is between about 60 percent and about 77 percent of the metallic cup diameter D1.

[0097] In one embodiment, the relationship between the projection depth 62 (or S), an inner diameter D3 of the projection sidewall 66, the metallic cup diameter 60 (or D1), and the change in sidewall height (54, 58) can be approximated as:

[00001] $H_{o} - H S .Math. \frac{.Math. D .Math. 3}{.Math. D .Math. 1}$

Thus, the height 58 (or H) of the metallic cup 46 with a projection 44 can be described as:

H>=Ho=S*{D3/D1}

Said another way, forming a projection 44 in the metallic cup reduces the sidewall height 58 (or H) by at least the projection depth 62 (or S) multiplied by the ratio of the projection inner diameter D3 divided by the metallic cup diameter D1. In one embodiment, the projection depth 62 (or S) may be expressed as:

S(H.sub.oH)*(D1/D3)

[0098] In another embodiment, the projection depth 62 (or S) is not more than the sidewall height 58 (or H):

[0099] The projection depth 62 (S) is designed based on the amount of material needed to increase the height of the sidewall of the finished container manufactured from the metallic cup 46. Stated otherwise, the projection 44 provides additional material to extend a sidewall portion 88 of a redrawn cup 84 (illustrated in FIG. 5E) formed from the metallic cup 46. Accordingly, as the projection depth 62 increases, the height of the sidewall portion 88 increases proportionally.

[0100] Optionally, in one embodiment, the projection depth 62 (or S) is between about 0.1 inches and about 2.5 inches. In another embodiment, the projection depth is between about 0.19 inches and about 1.19 inches. Optionally, the projection depth is between about 0.49 inches and about 0.89 inches in yet another embodiment. In one embodiment, the projection depth 62 is between about 5 percent and about 100 percent of the sidewall height 58 (H) of the reformed cup 46. In another embodiment, the projection depth 62 is between about 20 percent and about 75 percent of the sidewall height 58. In still another embodiment, the projection depth 62 is between about 10 percent and about 30 percent of the sidewall height 58.

[0101] The end-wall 68 of the projection 44 has a diameter D8. In one embodiment, the end-wall diameter D8 is between about 1.1 inches and about 2.1 inches or between about 1.3 inches and about 1.9 inches. Alternatively, in a more preferred embodiment, the end-wall diameter D8 is between about 1.5 inches and about 1.7 inches. In one embodiment, the end-wall diameter D8 is between about 25 percent and about 60 percent of the metallic cup diameter 60 (or D1). Alternatively, the end-wall diameter D8 is between about 31 percent and about 48 percent of the metallic cup diameter D1. In one embodiment, the end-wall 68 is substantially linear.

[0102] Referring now to FIGS. 5A-5E, a bodymaker 70 in one embodiment of the present invention is illustrated reversing the projection 44 of the metallic cup 46 and subsequently drawing the metallic cup 46 in one continuous operation. Bodymaker 70 is similar to bodymakers described in PCT Publication WO 2014/047115, PCT Publication WO 2014/110387, and U.S. Pat. No. 9,387,530 which are each incorporated herein in their entirety.

[0103] The bodymaker 70 generally comprises a punch 72, a ram 74, a pressure sleeve 76, and a redraw die 78. In one embodiment, the punch 72 is interconnected to the ram 74 by a fastener, such as a bolt 80. The pressure sleeve 76 has an exterior diameter selected to be no greater than the interior diameter of the metallic cup 46. Accordingly, the pressure sleeve 76 may be positioned within an interior of the metallic cup 46.

[0104] In operation, the pressure sleeve 76 is advanced in a first direction toward the redraw die 78 to clamp the metallic cup 46 in a predetermined alignment with respect to the tooling of the bodymaker 70. The ram 74 advances the punch 72 in the first direction such that one or more of the punch 72 and the punch bolt 80 contact the protrusion 44. This is generally illustrated in FIG. 5A where a face portion of the punch 72 is separated from the redraw die 78 by a distance 82 which is equal to the projection depth S, or 1.0S.

[0105] Referring now to FIG. 5B, as the ram 74 continues advancing in the first direction, one or more of the punch 72 and the punch bolt 80 apply a force to the projection 44, beginning to reverse the projection 44 and rolling the projection 44 partially into an aperture 79 of the redraw die 78. The distance 82 between the face portion of the punch and the redraw die is approximately seven tenths of the projection depth S, or 0.7S.

[0106] As the ram 74 continues advancing in the first direction, as illustrated in FIG. 5C, the punch face portion begins to pass through the redraw die aperture 79. At this point, the bodymaker 70 is about midway through the process of reversing the projection 44 beyond the lowermost portion of the closed end-wall 41. The distance 82 between the face portion of the punch and the redraw die is now approximately positive two tenths of the projection depth S, or about +0.2S. Referring now to FIG. 5D, the reversal of the projection 44 is complete when the distance 82 is about +1.0S.

[0107] Referring now to FIG. 5E, after the projection has been reversed, the ram 74 continues to advance in the first direction through the redraw die aperture 79 to draw the metallic cup. In this manner, a redrawn cup 84 is formed. During the reversal of the projection 44 and subsequent drawing the metallic cup 46 by the bodymaker 70, the material thickness T of the closed end-wall 41 does not substantially change. In one embodiment, a portion of the sidewall 88 of the redrawn cup 84 may decrease in thickness by up to about 90 percent of the original thickness T of the metallic cup 46. Another portion of the sidewall 88 may thicken by up to about 115 percent of the original thickness T proximate to an open end of the redrawn cup 84. The redrawn cup 84 has a closed end-wall portion 86 with a decreased diameter compared to diameter 60 of the metallic cup 46. The sidewall portion 88 of the redrawn cup 84 has an increased height compared to the sidewall height 58 of metallic cup 46. In one embodiment, the sidewall portion 88 has a height that is from about 30 percent to about 95 percent greater than the height 58 of the sidewall 43 of the cup 46. In one embodiment, the sidewall portion 88 is at least about 6% longer than the sidewall portion formed by redrawing a metallic cup with the same diameter 60 and sidewall height 58 that does not have an inwardly oriented projection.

[0108] Certain features of the metallic cup projection 44 must have specific proportional relationships with the bodymaker redraw die 78 for successful reversal of the projection 44 and redraw of the metallic cup 46. Referring again to FIG. 4B, in one embodiment, the outer diameter 64 (or D2) of the projection sidewall 66 is no more than seven-eighths of the metallic cup diameter 60 (or D1), or:

D2D1(7/8)

In another embodiment, the inner diameter D3 of the projection sidewall 66 can be smaller than or equal to, but must not be greater than, the outer diameter 64 (or D2) of the projection sidewall 66 reduced by six times the metal thickness T. This relationship can be expressed as:

D3<=D26*t

This relationship ensures that there is adequate room for the projection 44 to be pushed through the redraw die aperture 79 without fracturing or wrinkling the metallic workpiece 46.

[0109] In still another embodiment, the inner diameter D3 of the projection sidewall 66 is less than or equal to seven-eighths of the metallic cup diameter 60 (or D1) reduced by six times the metal thickness T, or

D3<=(D1*7/8)6*T

[0110] Referring again to FIG. 5A, the redraw die aperture 79 has a predetermined diameter D5 and a predetermined radius R4. In one embodiment, the aperture diameter D5 of the redraw die 78 is between about 2.1 inches and about 3.1 inches. In a more preferred embodiment, the aperture diameter D5 is between about 2.51 inches and about 2.71 inches.

[0111] In one embodiment, the redraw aperture radius R4 is greater than four times the metal thickness T of the metallic cup 46, or

R4>4*T

[0112] The diameter D6 of the aperture radius R4 is about equal to the aperture diameter D5 plus two times the aperture radius R4. More specifically, in one embodiment the redraw radius diameter D6 may be expressed as:

D6=D5+(2*R4)

The redraw radius diameter D6 may also be expressed as being not less than the diameter D4 of the projection outer radius R2 minus two times the projection outer radius R2 minus the redraw radius R4, or as:

D6D4(2*(R2R4))

In one embodiment, the redraw radius diameter D6 is between about 2.4 inches and about 3.4 inches. In a more preferred embodiment, the redraw radius diameter D6 is between about 2.81 inches and about 3.01 inches.

[0113] The diameter D5 of the redraw aperture 79 has a predetermined relationship to the diameter D4 of the projection outer radius R2. Generally, the outer diameter D4 is greater than the redraw aperture diameter D5. More specifically, the projection outer diameter D4 is less than or equal to the aperture diameter D5 plus two times the projection outer radius R2, which may be expressed as:

D4D5+(2*R2)

or alternatively as:

D5D4(2*R2)

Alternatively, the projection outer diameter D4 may also be expressed in relation to the projection outer radius R2 and the diameter D6 of the redraw radius R4. The draw radius R4 of the redraw die 78 has a size such that the projection 44 has sufficient room to pass through the redraw die aperture 79. More specifically, in one embodiment, the projection outer diameter D4 is limited to:

D4D6+2*(R2R4)

This proportional relationship ensures the projection 44 has sufficient room to be pushed through the redraw die aperture 79 without fracturing or wrinkling the metallic workpiece 46.

[0114] As one of skill in the art will appreciate, the aperture diameter D5 is greater than the diameter D7 of the bodymaker punch 72 such that:

D5>D7

In one embodiment, the punch diameter D7 is between about 2.0 inches and about 3.1 inches. Optionally, in a more preferred embodiment, the punch diameter D7 is between about 2.4 inches and about 2.8 inches.

[0115] The aperture diameter D5 is also related to the diameter of the metallic cup D1 which is known as the draw ratio. More specifically, the draw ratio is expressed as the metallic cup diameter 60 (or D1) divided by the aperture diameter D5. In one embodiment, the draw ratio is no more than 2.0. Accordingly, the draw ratio may be expressed as:

Draw ratio=(D1/D5)2.0

or alternatively as:

D5D1/2

[0116] Generally, in all embodiments, the metallic cup outer radius R1, the projection outer radius R2, the projection inner radius R3, and the redraw radius R4 are each greater than or equal to four times the metal thickness T, such that: R1, R2, R3, R44*T.

[0117] The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limiting of the invention to the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments described and shown in the figures were chosen and described in order to best explain the principles of the invention, the practical application, and to enable those of ordinary skill in the art to understand the invention.

[0118] While various embodiments of the present invention have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. Moreover, references made herein to the present invention or aspects thereof should be understood to mean certain embodiments of the present invention and should not necessarily be construed as limiting all embodiments to a particular description. It is to be expressly understood that such modifications and alterations are within the scope and spirit of the present invention, as set forth in the following claims.

Apparatus and Method for Redrawing a Cup with a Reformed Bottom

Assignee

Inventors

Cpc classification

Classification Explorer

B65D7/04

PERFORMING OPERATIONS; TRANSPORTING

Classification Explorer

B21D22/24

PERFORMING OPERATIONS; TRANSPORTING

Classification Explorer

B65D1/40

PERFORMING OPERATIONS; TRANSPORTING

Classification Explorer

B21D22/28

PERFORMING OPERATIONS; TRANSPORTING

Classification Explorer

B21D51/26

PERFORMING OPERATIONS; TRANSPORTING

International classification

Classification Explorer

B21D22/28

PERFORMING OPERATIONS; TRANSPORTING

Classification Explorer

B65D1/40

PERFORMING OPERATIONS; TRANSPORTING

Abstract

Claims

Description