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.

What is claimed is: 
     
         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.