Reduced gauge bottle cap

Abstract

A reduced gauged crown for a container opening includes a corrugated panel portion such that the corrugation strengthens the crown material and allows less material to be used for the crown than would be used for an uncorrugated bottle cap.

What is claimed is: 
     
         1 . A reduced gauge crown for a pressurized container opening, the crown comprising:
 a top portion,   an inner portion contiguous with the top portion,   an outer portion contiguous with the top portion, the outer portion being formed into an annular skirt that descends from the top portion,   CHARACTERIZED IN THAT:   the inner portion comprises a central portion comprising a recessed panel; and   the crown has a thickness gauge in the range of 0.16 mm to 0.18 mm, and material comprising the crown has an average hardness of greater than 62 on a 30T hardness scale but less than an upper limit of hardness set by the maximum stress acceptable to the container during a crimping process or the spring back associated with a harder material;   wherein the recessed panel comprises a uniform thickness across its entirety, and is parallel with the top portion but positioned entirely below a bottom surface of the top portion, the central portion comprising a concentric downward formed curved transition surface contiguously connecting the top portion and the recessed panel, the transition surface and recessed panel together stiffening the inner portion by providing material strengthening perpendicular to the direction of the downward formed recessed panel.   
     
     
         2 . The crown of  claim 1 , wherein material comprising the crown has an average hardness of greater than 65 on the 30T hardness scale. 
     
     
         3 . The crown of  claim 1 , wherein material comprising the crown has an average hardness of greater than 68 on the 30T hardness scale. 
     
     
         4 . The crown of  claim 1 , wherein material comprising the crown has an average hardness of greater than 71 on the 30T hardness scale. 
     
     
         5 . The crown of  claim 1 , wherein material comprising the crown has an average hardness of greater than 73 on the 30T hardness scale. 
     
     
         6 . The crown of  claim 1 , wherein the transition surface and recessed panel together provide material strengthening substantially equal to material strengthening provided by a crown without the central portion, and having a thickness gauge in the range of 0.21 mm to 0.23 mm and comprising material having an average hardness of approximately 61 on the 30T hardness scale. 
     
     
         7 . The crown of  claim 1 , wherein the transition surface comprises a plurality of concave concentric rings formed downward into the top portion that progress from the a top of the skirt toward a center of the crown. 
     
     
         8 . The crown of  claim 1 , wherein the transition surface comprises a plurality of concave circular depressions formed downward into the top portion that progress from the a top of the skirt toward a center of the crown. 
     
     
         9 . A method for making a reduced gauge crown for a pressurized container, the method comprising:
 shaping a sheet of crown material to provide a top portion, an inner portion contiguous with the top portion, and an outer portion contiguous with the top portion and formed into an annular skirt that descends from the top portion;   CHARACTERIZED IN THAT the method further comprises:   employing crown material having a thickness gauge in the range of 0.16 mm to 0.18 mm, and having an average hardness of greater than 62 on a 30T hardness scale;   forming the inner portion into a central portion comprising a recessed panel having a uniform thickness across its entirety, and is parallel with the top portion but positioned entirely below a bottom surface of the top portion; and   forming the central portion by downwardly forming a concentric curved transition surface contiguously connecting the top portion and the recessed panel such that the transition surface and recessed panel together stiffen the inner portion by providing material strengthening perpendicular to the direction of the downward formed recessed panel.   
     
     
         10 . The method of  claim 9 , wherein material comprising the crown has an average hardness of greater than 65 on the 30T hardness scale. 
     
     
         11 . The method of  claim 9 , wherein material comprising the crown has an average hardness of greater than 68 on the 30T hardness scale. 
     
     
         12 . The method of  claim 9 , wherein material comprising the crown has an average hardness of greater than 71 on the 30T hardness scale. 
     
     
         13 . The method of  claim 9 , wherein material comprising the crown has an average hardness of greater than 73 on the 30T hardness scale. 
     
     
         14 . The method of  claim 9 , wherein the transition surface and recessed panel together provide material strengthening substantially equal to material strengthening provided by a crown without the central portion, and having a thickness gauge in the range of 0.21 mm to 0.23 mm and comprising material having an average hardness of approximately 61 on the 30T hardness scale. 
     
     
         15 . The method of  claim 9 , wherein the transition surface comprises a plurality of concave concentric rings formed downward into the top portion to descending depths that progress from the skirt toward a center of the crown. 
     
     
         16 . The crown of  claim 9 , wherein the transition surface comprises a plurality of concave circular depressions formed downward into the top portion that progress from the a top of the skirt toward a center of the crown.