Apparatus and Method for Redrawing a Cup with a Reformed Bottom

FIELD OF THE INVENTION

The present invention relates generally to the manufacturing of metallic cups from flat sheet material to form container bodies. More specifically, the present invention relates to methods and apparatus for forming metallic cups with reduced height and reformed bottoms having an inwardly oriented projection. The cups are subsequently formed into metallic container bodies, such as aerosol containers.

BACKGROUND

Metallic containers offer distributors and consumers many benefits by providing optimal protection properties for products. For example, metallic containers prevent CO₂migration and block UV radiation which can have a damaging effect on personal care, pharmaceutical, and food products and on other UV-sensitive formulations, negatively influencing the effectiveness of ingredients, as well as the fragrance, appearance, flavor, or color of the product. Metallic containers also offer an impermeable barrier to light, water vapor, oils and fats, oxygen and micro-organisms and keep the contents of the container fresh and protected from external influences, thereby guaranteeing a long shelf-life.

The increased durability of metallic containers compared to glass containers reduces the number of containers damaged during processing and shipping, resulting in further savings. Additionally, metallic containers are lighter than glass containers of comparable size, resulting in energy savings during shipment. Further, metallic containers can be manufactured with high burst pressures which make them ideal and safe for use as containers holding products under pressure, such as aerosol containers. Finally, recycling metallic containers is generally easier than recycling glass and plastic containers because labels and other indicia are printed directly onto the metallic body of the container while glass and plastic containers typically have labels that must be separated during the recycling process.

Metallic containers may include a container body that is formed in a draw and wall ironing (DWI) process separately from a can end. The manufacture of the DWI container body starts by forming a cup from a metallic stock material which is typically shipped and stored in large rolls. Referring to FIG. 1, which depicts the prior art process, a sheet 4 of metallic stock material is fed into a draw-redraw apparatus 2. As shown in FIG. 1A, a blank and draw die 6 cuts a blank 8 from the sheet 4. The blank 8 can have any desired shape. The cut blank 8 is illustrated in FIG. 1A separate from apparatus 2 for clarity. The blank and draw die 6 then draws the blank 8 into a cup 9 with sidewalls 10 and a closed end-wall 11 with a first diameter, as illustrated in FIG. 1B.

Referring now to FIGS. 1C-1D, optionally a redraw die 12 redraws the cup 9 into a formed cup 13 with a closed end-wall 14. As will be appreciated by one of skill in the art, during a redraw operation, the direction of the sidewalls 15 of the cup 14 are reversed. Thus, the open end of the cup 13 faces a direction substantially opposite of the direction of the open end of cup 9. The redraw operation also generally lengthens the sidewalls 15 compared to sidewalls 10 of cup 9, reducing the diameter of the closed end-wall 14. Thus, the end-wall 14 of the formed cup 13 has a second diameter that is less than the first diameter. The formed cup 13 is then ejected from the apparatus 2 and another portion of the sheet 4 is fed into the apparatus 2, as illustrated in FIG. 1E. In the prior art apparatus 2 illustrated in FIG. 1, the formed cup 13 has a cross-section with generally linear sidewalls 15, as shown in FIG. 1D. The closed end-wall 14 is also generally linear. After forming the cup 13, the apparatus 2 ejects the cup in a direction substantially perpendicular to the sheet 4 of stock material. The formed cup 13 is subsequently formed into a container body by a bodymaker by methods known to those of skill in the art. Generally, the size of the container body is directly related to the size of the blank 8 used to form the formed cup 13, i.e., the larger the blank, the more material that is present to form the formed cup 13 and, subsequently, the container body.

To form a taller or wider container body, such as an aerosol container, current manufacturing methods require a blank of a larger size resulting in a formed cup 13 with an increased height. For example, to form a taller or wider container body using the method and apparatus of FIGS. 1A-1E, the height of the sidewall 15 of the formed cup 13 is increased. However, as the height of the formed cup increases, the bodymaker must use a longer punch stroke and longer stroke redraw carriage to form the formed cup 13 into the container body, reducing the speed and efficiency of the bodymaker.

Accordingly, there is an unmet need for a method and apparatus of forming a cup from a blank with a larger size without increasing the height of the cup so that the cup can be reformed into a larger container body without reducing the speed and efficiency of a conventional bodymaker. Further, by utilizing conventional bodymaker tools, equipment costs can be reduced because a conventional bodymaker may be modified to redraw the larger container body without increasing the stroke length of the redraw carriage. The present invention is particularly useful to manufacture metallic cups which can be utilized in a bodymaker to form aerosol containers.

SUMMARY OF THE INVENTION

The present invention provides novel methods and apparatus for forming a cup with a reformed closed end-wall having an inwardly oriented projection for the purpose of reducing the overall height of the cup. After the cup with the reformed closed end-wall is formed, the cup may be formed into a container body of any size, shape, or type for any product. One aspect of the present invention is to provide a cup with a reformed closed end-wall. The cup generally comprises, but is not limited to, an open end, a sidewall, a closed end-wall, and an inwardly oriented protrusion formed in a portion of the closed end-wall. In one embodiment of the present invention, the cup has a reduced height compared to a cup of a similar diameter formed from a blank of substantially the same size.

Another aspect of the present invention is to provide a die center punch with a cavity. The die center punch is adapted to support a portion of an interior surface of a cup end-wall as an inward projection is formed in the cup.

Still another aspect of the present invention is a reform punch with an extension. The extension is adapted to apply pressure to a portion of an exterior surface of a cup end-wall to form an inward projection in the cup.

Another aspect of the present invention is a draw-redraw apparatus operable to form a cup with a reformed closed end-wall and a reduced cup height. In one embodiment, the draw-redraw apparatus includes a die center punch, a reform punch, and a reform draw pad. The reform draw pad has a cavity therethrough that aligns with an extension of the reform punch. At least a portion of the extension passes at least partially through the cavity of the reform draw pad and applies a force to a predetermined portion of a bottom surface of the cup. A portion of the bottom of the cup is deformed into a cavity formed at the end of the die center punch, forming an inwardly oriented projection in the bottom of the cup.

Another aspect of the present invention is to provide a metallic cup with an inwardly oriented protrusion having a predetermined geometry to accommodate use in a conventional bodymaker. In one embodiment, extended length containers, such as aerosol cans, may be manufactured from the metallic cup in a cost effective manner without requiring new equipment and capital expenditures that would otherwise be required to produce the extended length containers. The metallic cup generally includes an exterior sidewall interconnected to a closed end-wall by a first radius. The inwardly oriented protrusion includes an interior sidewall interconnected to the closed end-wall by a second radius with an outer diameter. The interior sidewall of the inwardly oriented protrusion has an outer diameter and an inner diameter. In one embodiment, the inner diameter is smaller than the outer diameter by at least six times a thickness of the metallic cup. In one embodiment a substantially horizontally oriented protrusion end-wall extends between an interior portion of a third radius interconnected to the interior sidewall of the inwardly oriented protrusion.

The second radius of the metallic cup must be sized such that the protrusion has room to pass through an aperture of the redraw die. The redraw die aperture has a redraw radius with a redraw radius diameter. In one embodiment, the outer diameter of the second radius is smaller than the redraw radius diameter plus two times the second radius reduced by two times the redraw radius.

It is one aspect of the present invention to provide a metallic cup with an inwardly oriented projection. The metallic cup includes, but is not limited to: (1) an exterior sidewall with a first height and a first diameter; (2) a closed end-wall interconnected to the exterior sidewall by a first radius; and (3) the inwardly oriented projection having: (i) a projection sidewall interconnected to the closed end-wall by a second radius; and (ii) 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. Optionally, 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. In one embodiment, 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. Optionally, the metallic cup is formed of a metallic material with a predetermined thickness that is substantially uniform.

In one embodiment, the depth of the inwardly oriented projection is between about 0.1 inches and about 2.5 inches. In another embodiment, the inwardly oriented projection has a depth that is at least equal to the first diameter divided by an inner-most diameter of the projection sidewall multiplied by a height of the metallic cup before the inwardly oriented projection is formed minus the first height of the exterior sidewall.

In one embodiment, the inwardly oriented projection has a frustoconical cross-section. Accordingly, the projection sidewall is optionally oriented at an angle of between about 95° and about 158° with respect to the closed end-wall. In another embodiment, 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. Optionally, in yet another embodiment, the maximum diameter of the projection end-wall is between about 1.1 inches and about 2.1 inches.

In one embodiment, 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. In another embodiment, the 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. Additionally, or alternatively, the outer-most diameter of the inwardly oriented projection is between about 1.5 inches and about 3.0 inches. In another embodiment, the outer-most diameter of the inwardly oriented projection is at least about 30 percent of the first diameter of the metallic cup. Optionally, each of the second radius and the third radius are not less than four times a material thickness of the metallic cup.

It is another aspect of the present invention to provide an apparatus adapted to form a metallic container with an extended sidewall by redrawing a metallic cup with an inwardly oriented projection. The apparatus generally comprises: (1) 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) a projection sidewall interconnected to the closed end-wall by a second radius which has an outer-most diameter; and (b) 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; (2) 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; (3) a ram; and (4) a punch interconnected to the ram, the punch aligned substantially concentrically with the redraw die aperture. In operation, 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. Optionally, in one embodiment, 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.

In one embodiment, the metallic container with the extended sidewall is formed without substantially changing a thickness of the closed end-wall of the metallic cup during the redrawing of the metallic cup. In another embodiment, a portion of the sidewall may decrease in thickness by up to about 90 percent of the original thickness of the metallic cup. Another portion of the sidewall may thicken by up to about 115 percent of the original thickness proximate to an open end of the metallic container with the extended sidewall. In another embodiment, the extended sidewall of the metallic container has a length that is between about 30 percent to about 95 percent greater than the first height of the metallic cup exterior sidewall. In one embodiment, the closed end-wall and the projection of the metallic cup with the inwardly oriented projection have a substantially uniform thickness.

In one embodiment, 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. In another embodiment, the projection sidewall of the inwardly oriented projection has an outer-most diameter that is not greater than seven-eighths of a diameter of the exterior sidewall of the metallic cup. Optionally, in another embodiment, the outer-most diameter of the inwardly oriented projection is at least about 30 percent of the diameter of the exterior sidewall. In one embodiment, an inner-most diameter of the projection sidewall is not more than the outer-most diameter of the projection sidewall minus six times a thickness of the metallic cup.

Still another aspect of the present invention is a method of redrawing a metallic cup having an inwardly oriented projection to form a metallic container with an extended sidewall. The method generally includes, but is not limited to: (1) providing the metallic cup, including: (a) an exterior sidewall with a first diameter and a first length; (b) a closed end-wall interconnected to a lower end of the exterior sidewall by a first radius; and (c) 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; (2) 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 (3) 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. In this manner, the first length of the exterior sidewall is extended from at least about 30 percent to about 95 percent. In one embodiment, the inwardly oriented projection has a frustoconical cross-section.

In one embodiment, 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. Optionally, the outer-most diameter of the projection sidewall is at least about 30 percent of the first diameter of the metallic cup. In another embodiment, an inner-most diameter of the projection sidewall of the inwardly oriented projection is not more than the outer-most diameter of the projection sidewall minus six times a material thickness of the metallic cup.

In one embodiment, 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. In another embodiment, 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.

In accordance with one aspect of the present invention, a novel method of forming a metallic cup having a sidewall and a reformed bottom is provided. This includes, but is not limited to, a method generally comprising: (1) providing a sheet of stock metal material; (2) shearing the sheet of stock metal material with a cutting tool to form a substantially circular blank with a predetermined size; (3) drawing the blank into a cup with a first diameter by pushing a peripheral edge of the blank downward with a first tool while supporting an interior portion of the blank with a second tool, the cup including a closed end-wall; (4) reforming the cup by applying pressure to an exterior portion of the closed end-wall of the cup to form an inwardly oriented protrusion while reducing a height of the cup, the protrusion reducing the interior volume of the cup; and (5) ejecting the metallic cup. In one embodiment, the method may further comprise redrawing the cup with the first diameter with a redraw die to form a cup with a second diameter that is less than the first diameter.

In one embodiment, reforming the cup to form an inwardly oriented protrusion comprises utilizing a die center punch with a cavity formed therein. The inwardly oriented protrusion is formed at least partially within the cavity of the die center punch by applying pressure to an exterior surface of the cup end-wall with a reform punch which extends at least partially through the cavity of the reform draw pad. In one embodiment, the reform punch includes an extension with a generally cylindrical shape. In another embodiment, the extension has a horizontal cross-sectional shape that substantially conforms to a horizontal cross-sectional shape of the cavity of the die center punch.

In one embodiment, the inwardly oriented projection in the bottom portion of the cup formed by the extension of the reform punch has a generally cylindrical shape. In another embodiment, the inwardly oriented projection in the bottom portion of the cup has a shape that is not cylindrical. For example, in one embodiment, the reform punch is generally conically shaped. In yet another embodiment, the reform punch generally has the shape of a frustum.

In one embodiment, reforming the cup to form the inwardly oriented protrusion decreases a height of the cup. Optionally, the protrusion has a height that is between about 5% and about 100% of the height of the reformed cup. Alternatively, the protrusion height may be between about 10% and about 90% of the reformed cup height. In another embodiment, the protrusion has a height that is between about 20 percent and about 75 percent of the height of the reformed cup. In still another embodiment, the protrusion height is between about 0.25 inches and about 2.5 inches and the protrusion has a diameter of between about 1.5 inches and about 3.0 inches. In one embodiment, the protrusion diameter is at least about 30 percent of the first diameter of the cup.

A diameter of the cup with the inwardly oriented protrusion is substantially the same as the first diameter of the cup. In another embodiment, the diameter of the metallic cup with the protrusion is at least about 5% less than a diameter of cup of approximately the same height and formed from a blank of approximately the same diameter that does not have an inwardly oriented projection. In still another embodiment, the protrusion reduces the internal volume of the cup by at least about 10%. It will be appreciated that varying the dimensions of the protrusion change internal volume of a cup with a protrusion. Accordingly, in still another embodiment, a cup with a protrusion has an internal volume that is reduced by from about 15% to about 22% compared to the same cup without the protrusion.

In another embodiment, reforming the cup comprises extending an unsupported portion of the closed end-wall of the cup. Optionally, reforming the cup comprises applying pressure through a cavity of the second tool, the cavity having a generally circular shape with an interior diameter of between about 1.5 inches and about 3.0 inches. In one embodiment, the second tool that supports the center portion of the blank comprises a reform draw pad with a cavity formed there-through. The reform draw pad is positioned between the reform punch and the die center punch. In one embodiment, the cavity is substantially centered on the reform draw pad. In another embodiment, the cavity of the reform draw pad has a generally circular shape.

In one embodiment, the blank has a generally circular shape, but in another embodiment, the blank has a non-circular shape. In another embodiment, the blank has a shape resembling one of an oval, a square, a rectangle, a triangle, a circle, or any combination thereof.

In one embodiment, the metallic cup has a generally cylindrical shape. In another embodiment, the metallic cup is not cylindrical. In one embodiment, the inwardly oriented protrusion is formed without substantially changing a thickness of the closed end-wall of the cup. In another embodiment, the closed end-wall and the inwardly oriented protrusion of the cup have a substantially uniform thickness.

It is another aspect of the present invention to provide a method of forming a metallic cup with an inwardly oriented protrusion. The method generally comprises, but is not limited to: (1) providing a sheet of stock metallic material; (2) cutting the sheet of stock metallic material with a cutting tool to form a substantially circular metallic blank with a predetermined size; (3) drawing the substantially circular metallic blank into a cup with a first diameter by pushing a peripheral edge of the blank with a first tool while supporting an interior portion of the blank with a second tool, the cup including a closed end-wall and a sidewall; (4) redrawing the cup to form a redrawn cup with a second diameter that is less than the first diameter; (5) reforming the redrawn cup by applying pressure through a cavity of the second tool to a portion of the closed end-wall to form a protrusion within an interior of the redrawn cup, the protrusion reducing a length of a sidewall of the redrawn cup and reducing the interior volume of the redrawn cup; and (6) ejecting the metallic cup.

In one embodiment, reforming the cup to form the protrusion does not substantially change the second diameter of the cup. In another embodiment, reforming the cup to form the protrusion does not substantially change a thickness of the closed end-wall of the cup. In another embodiment, the closed end-wall and the protrusion of the cup have a substantially uniform thickness.

In one embodiment, reforming the cup comprises extending an unsupported portion of the closed end-wall of the cup into a cavity of a die center punch positioned within the interior of the cup. In still another embodiment, a reform punch applies pressure to an unsupported bottom surface portion of the closed end-wall of the cup during the reforming. In one embodiment, a reform draw pad is positioned between the reform punch and the closed end-wall of the cup during the reforming. The reform draw pad includes a cavity to receive at least a portion of the punch.

In one embodiment, the protrusion has a height of between about 5% and about 100% of the sidewall length of the redrawn cup. In another embodiment, the protrusion height is between about 0.25 inches and about 2.5 inches. Optionally, the protrusion may have a diameter of between about 1.5 inches and about 3.0 inches. Additionally, or alternatively, the protrusion diameter may be not less than about 30 percent of the first diameter of the cup. In one embodiment, the length of the sidewall of the redrawn cup with the protrusion is between about 60 percent and about 97 percent of the length of the sidewall of the redrawn cup without the protrusion.

In accordance with another aspect of the present invention, an improved apparatus for forming a metallic cup having an inwardly extending projection from a cup with a substantially flat bottom portion is disclosed. The improvement generally comprises, but is not limited to: (1) providing a metallic cup with a substantially flat bottom portion and a sidewall; (2) a first tool to support an interior surface of the bottom portion of the metallic cup proximate to at least the sidewall; and (3) a second opposing tool to apply pressure to an exterior surface of the bottom portion of the metallic cup opposite of the first tool, the second tool comprising a projection which travels at least partially into a cavity formed in the first tool to form an inwardly oriented projection in the cup bottom portion. In one embodiment, the inwardly oriented projection has a height of at least about 5 percent and up to about 100 percent of a sidewall height of the metallic cup with the inwardly oriented projection. Additionally, or alternatively, the sidewall height of the metallic cup with the inwardly extending projection is between about 60 percent and about 97 percent of a height of the sidewall of the metallic cup with the substantially flat bottom portion.

In one embodiment, the first tool comprises a die center punch with the cavity formed therein. Optionally, the cavity has a depth at least equal to a height of the inwardly extending projection. In one embodiment, the cavity of the die center punch has a diameter of between about 1.5 inches and about 3.0 inches. In another embodiment, the second tool comprises a reform punch with an upwardly extending projection.

In one embodiment, a reform draw pad with a substantially centered cavity is positioned between the first tool and the second tool as the inwardly oriented projection is formed. In another embodiment, the sidewall of the metallic cup is supported by a third tool as the inwardly oriented projection is formed.

In one embodiment, the cavity of the reform draw pad has a shape that is generally round, oval, square, rectangular, triangular, or any combination thereof. In one embodiment, the extension of the reform punch has a shape that is generally spherical, conical, cylindrical, rectangular, triangular, a frustum, or any combination thereof.

It is another aspect of the present invention to provide a metallic cup with an inwardly extending projection. The metallic cup generally includes: (1) a cylindrical sidewall with a height of between about 2 inches and about 5 inches; (2) a closed end-wall with a diameter of between about 2.5 inches and about 5 inches; and (3) an inwardly oriented projection formed in the closed end-wall. In one embodiment, the projection has a frustoconical cross-section. Additionally, the projection may have a height of between about 0.25 inches and about 2.5 inches and a diameter of about 1.5 inches to about 3 inches. In another embodiment, forming the inwardly oriented projection decreases the height of the cylindrical sidewall by at least about 3 percent. Optionally, the inwardly oriented projection has a diameter that is at least about 30 percent of a diameter of the metallic cup.

In one embodiment, the projection height is between about 5 percent and about 100 percent of the sidewall height. In another embodiment, the diameter of the closed end-wall with the projection is at least about 5% less than a diameter of cup of approximately the same height and formed from a blank of approximately the same diameter that does not have an inwardly extending projection. In another embodiment, the metallic cup with the inwardly extending projection has a volume that is between about 5% and about 40% less than a cup formed from a blank of approximately the same diameter that does not have an inwardly extending projection. In one embodiment, the closed end-wall and the projection of the metallic cup have a substantially uniform thickness.

The above-described embodiments, objectives, and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the invention are possible using, alone or in combination, one or more of the features set forth above or described in detail below.

As will be appreciated by one of skill in the art, the method and apparatus of the current invention may be used to form cups of any material used to form metallic containers, including without limitation aluminum, tin, steel, and combinations thereof. Further, the method and apparatus of the current invention may be used to form cups that are subsequently formed into container bodies or vessels of any size and shape and for storing any type of product for any industry. Accordingly, cups formed by the method and apparatus of the present invention may be formed into containers or vessels used to store or contain liquids and gases of all types, including consumer products and beverages as well as industrial chemicals and products.

The phrases “at least one,” “one or more,” and “and/or,” as used herein, are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C,” “at least one of A, B, or C,” “one or more of A, B, and C,” “one or more of A, B, or C,” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.

Unless otherwise indicated, all numbers expressing quantities, dimensions, conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.”

The term “a” or “an” entity, as used herein, refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein.

The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Accordingly, the terms “including,” “comprising,” or “having” and variations thereof can be used interchangeably herein.

It shall be understood that the term “means” as used herein shall be given its broadest possible interpretation in accordance with 35 U.S.C., Section 112(f). Accordingly, a claim incorporating the term “means” shall cover all structures, materials, or acts set forth herein, and all of the equivalents thereof. Further, the structures, materials, or acts and the equivalents thereof shall include all those described in the Summary of the Invention, Brief Description of the Drawings, Detailed Description, Abstract, and Claims themselves.

The Summary of the Invention is neither intended, nor should it be construed, as being representative of the full extent and scope of the present invention. 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. The present invention is set forth in various levels of detail in the Summary of the Invention as well as in the attached drawings and the Detailed Description and no limitation as to the scope of the present invention is intended by either the inclusion or non-inclusion of elements or components. Additional aspects of the present invention will become more readily apparent from the Detailed Description, particularly when taken together with the drawings.

BRIEF DESCRIPTION OF DRAWINGS

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.

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

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;

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;

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;

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

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;

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;

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;

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;

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

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.

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.

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:

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_o
Height of metallic cup without projection

ØD1
Diameter of metallic cup

ØD2
Projection sidewall outer diameter

ØD3
Projection sidewall inner diameter

ØD4
Diameter of projection outer radius

ØD5
Redraw die diameter

ØD6
Diameter of redraw radius

ØD7
Bodymaker punch diameter

ØD8
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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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%.

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.

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, R3≧4*T

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.

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_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_o

In one embodiment, forming the inwardly oriented projection 44 decreases the height H_oof 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_oof the redrawn cup 42 without the projection 44.

The metallic cup 46 may have a diameter 60 (or ØD1) that varies depending on the size of a metallic container being manufactured. In one embodiment, the diameter 60 (ØD1) 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 (ØD1) is between about 3.9 inches and about 4.0 inches in a more preferred embodiment.

In one embodiment, an outer diameter ØD4 of the projection outer radius R2 is between about 2.1 inches and about 3.3 inches. In another embodiment, the outer diameter ØD4 is between about 2.5 inches and about 2.9 inches. Optionally, in a more preferred embodiment, the outer diameter ØD4 is between about 2.65 inches and about 2.75 inches. In one embodiment, the outer diameter ØD4 is at least about 30 percent of the metallic cup diameter 60 (or ØD1). In another embodiment, the outer diameter ØD4 is between about 48 percent and about 94 percent of the metallic cup diameter ØD1. Alternatively, in another embodiment, the outer diameter ØD4 is between about 60 percent and about 77 percent of the metallic cup diameter ØD1.

In one embodiment, the relationship between the projection depth 62 (or “S”), an inner diameter ØD3 of the projection sidewall 66, the metallic cup diameter 60 (or ØD1), and the change in sidewall height (54, 58) can be approximated as:

$H_{o} - H \leq S \frac{\emptyset D 3}{\emptyset D 1}$

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

H>=Ho=S*{ØD3/ØD1}

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 ØD3 divided by the metallic cup diameter ØD1. In one embodiment, the projection depth 62 (or “S”) may be expressed as:

S≧(H_o−H)*(ØD1/ØD3)

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

S≦H

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.

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.

The end-wall 68 of the projection 44 has a diameter ØD8. In one embodiment, the end-wall diameter ØD8 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 ØD8 is between about 1.5 inches and about 1.7 inches. In one embodiment, the end-wall diameter ØD8 is between about 25 percent and about 60 percent of the metallic cup diameter 60 (or “ØD1”). Alternatively, the end-wall diameter ØD8 is between about 31 percent and about 48 percent of the metallic cup diameter ØD1. In one embodiment, the end-wall 68 is substantially linear.

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.

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.

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.

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.

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.

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.

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 ØD2) of the projection sidewall 66 is no more than seven-eighths of the metallic cup diameter 60 (or ØD1), or:

ØD2≦ØD1×(7/8)

In another embodiment, the inner diameter ØD3 of the projection sidewall 66 can be smaller than or equal to, but must not be greater than, the outer diameter 64 (or ØD2) of the projection sidewall 66 reduced by six times the metal thickness T. This relationship can be expressed as:

ØD3<=ØD2−6*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.

In still another embodiment, the inner diameter ØD3 of the projection sidewall 66 is less than or equal to seven-eighths of the metallic cup diameter 60 (or ØD1) reduced by six times the metal thickness T, or

ØD3<=(ØD1*7/8)−6*T

Referring again to FIG. 5A, the redraw die aperture 79 has a predetermined diameter ØD5 and a predetermined radius R4. In one embodiment, the aperture diameter ØD5 of the redraw die 78 is between about 2.1 inches and about 3.1 inches. In a more preferred embodiment, the aperture diameter ØD5 is between about 2.51 inches and about 2.71 inches.

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

The diameter ØD6 of the aperture radius R4 is about equal to the aperture diameter ØD5 plus two times the aperture radius R4. More specifically, in one embodiment the redraw radius diameter ØD6 may be expressed as:

ØD6=ØD5+(2*R4)

The redraw radius diameter ØD6 may also be expressed as being not less than the diameter ØD4 of the projection outer radius R2 minus two times the projection outer radius R2 minus the redraw radius R4, or as:

ØD6≧ØD4−(2*(R2−R4))

In one embodiment, the redraw radius diameter ØD6 is between about 2.4 inches and about 3.4 inches. In a more preferred embodiment, the redraw radius diameter ØD6 is between about 2.81 inches and about 3.01 inches.

The diameter ØD5 of the redraw aperture 79 has a predetermined relationship to the diameter ØD4 of the projection outer radius R2. Generally, the outer diameter ØD4 is greater than the redraw aperture diameter ØD5. More specifically, the projection outer diameter ØD4 is less than or equal to the aperture diameter ØD5 plus two times the projection outer radius R2, which may be expressed as:

ØD4≦ØD5+(2*R2)

or alternatively as:

ØD5≧ØD4−(2*R2)

Alternatively, the projection outer diameter ØD4 may also be expressed in relation to the projection outer radius R2 and the diameter ØD6 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 ØD4 is limited to:

ØD4≦ØD6+2*(R2−R4)

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.

As one of skill in the art will appreciate, the aperture diameter ØD5 is greater than the diameter ØD7 of the bodymaker punch 72 such that:

ØD5>ØD7

In one embodiment, the punch diameter ØD7 is between about 2.0 inches and about 3.1 inches. Optionally, in a more preferred embodiment, the punch diameter ØD7 is between about 2.4 inches and about 2.8 inches.

The aperture diameter ØD5 is also related to the diameter of the metallic cup ØD1 which is known as the draw ratio. More specifically, the draw ratio is expressed as the metallic cup diameter 60 (or “ØD1”) divided by the aperture diameter ØD5. In one embodiment, the draw ratio is no more than 2.0. Accordingly, the draw ratio may be expressed as:

Draw ratio=(ØD1/ØD5)≦2.0

or alternatively as:

ØD5≧ØD1/2

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, R4≧4*T.

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.

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.

	Number	Date	Country
Parent	14925477	Oct 2015	US
Child	15453139		US

Apparatus and Method for Redrawing a Cup with a Reformed Bottom

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