Can lid closure and method of joining a can lid closure to a can body

Abstract

A preferred embodiment of the disclosed can lid has a center panel having a central axis that is perpendicular to a diameter of the outer rim, or peripheral curl portion, of the can lid, an annular countersink surrounding the center panel, an arcuate chuckwall extending radially outward from the annular countersink, an arcuate step portion extending radially outward from the arcuate chuckwall, a transitional portion extending radially outward from the arcuate step portion, and a peripheral curl portion extending outwardly from the transitional portion.

I claim:  
     
         1 . A lid for a can body comprising: 
 a center panel having a central axis that is perpendicular to a diameter of the outer rim of said lid;    an annular countersink surrounding said center panel;    a chuckwall extending radially outward from said annular countersink, wherein a line passing through the ends of said chuckwall is at an angle with respect to said central axis of the center panel of from about 20° to about 80°; and    a peripheral curl portion having a height less than 0.091 inches extending radially outward from said chuckwall.    
     
     
         2 . The can lid according to  claim 1  wherein a line passing through the ends of said chuckwall is at an angle with respect to said central axis of the center panel of from about 30° to about 60°.  
     
     
         3 . The can lid according to  claim 1  wherein a line passing through the ends of said chuckwall is at an angle with respect to said central axis of the center panel of from about 40° to about 50°.  
     
     
         4 . The can lid according to  claim 1  wherein the height of said peripheral curl portion is from about 0.04 to about 0.09 inches.  
     
     
         5 . The can lid according to  claim 1  further comprising a transitional portion extending radially outward from said chuckwall, wherein the peripheral curl portion extends radially outward from said transitional portion.  
     
     
         6 . The can lid according to  claim 1  wherein said center panel is substantially flat or planar.  
     
     
         7 . The can lid according to  claim 1  wherein said center panel is arcuate.  
     
     
         8 . The can lid according to  claim 1  wherein said chuckwall is an arcuate chuckwall.  
     
     
         9 . The can lid according to  claim 8  wherein said arcuate chuckwall has a radius of curvature of from about 0.4 to about 1 inch, the center-point of said radius located below the profile of said lid.  
     
     
         10 . The can lid according to  claim 1  further comprising a step portion extending radially outward from said chuckwall.  
     
     
         11 . The can lid according to  claim 10  wherein said step portion is arcuate.  
     
     
         12 . The can lid according to  claim 1  I wherein said arcuate step portion has a radius of curvature of from about 0.02 to about 0.06 inches, the center-point of said radius being located above the profile of said lid.  
     
     
         13 . The can lid according to  claim 10  wherein said chuckwall is an arcuate chuckwall.  
     
     
         14 . The can lid according to  claim 13  wherein a line passing through the ends of said arcuate chuckwall is at an angle with respect to said central axis of the center panel of from about 30° to about 60°.  
     
     
         15 . The can lid according to  claim 13  wherein a line passing through the ends of said arcuate chuckwall is at an angle with respect to said central axis of the center panel of from about 40° to about 50°.  
     
     
         16 . The can lid according to  claim 13  wherein said arcuate chuckwall has a radius of curvature of from about 0.4 to about 1 inch, the center-point of said radius located below the profile of said lid.  
     
     
         17 . The can lid according to  claim 1  wherein said annular countersink has a height of from about 0.030 to about 0.115 inches.  
     
     
         18 . The can lid of  claim 17  wherein said chuckwall is an arcuate chuckwall having a radius of curvature of from about 0.4 to about 1 inch, the center-point of said radius being located below the profile of said lid.  
     
     
         19 . The can lid of  claim 17  further comprising a step portion extending radially outward from said chuckwall.  
     
     
         20 . The can lid according to  claim 19  wherein said chuckwall is an arcuate chuckwall.  
     
     
         21 . A lid for a can body comprising: 
 a center panel having a central axis that is perpendicular to a diameter of the outer rim of said lid;    an annular countersink surrounding said center panel;    a chuckwall extending radially outward from said annular countersink, wherein a line passing through the ends of said chuckwall is at an angle with respect to said central axis of the center panel of from about 20° to about 80°;    a step portion extending radially outward from said chuckwall;    a transitional portion extending radially outward from said step portion; and    a peripheral curl portion having a height less than 0.091 inches extending radially outward from said transitional portion.    
     
     
         22 . The can lid according to  claim 21  wherein said chuckwall is an arcuate chuckwall.  
     
     
         23 . The can lid according to  claim 21  wherein said step portion is an arcuate step portion.  
     
     
         24 . The can lid according to  claim 21  wherein said chuckwall is an arcuate chuckwall and said step portion is an arcuate step portion.  
     
     
         25 . A lid for a can body comprising: 
 a center panel having a central axis that is perpendicular to a diameter of the outer rim of said lid;    an annular countersink surrounding said center panel wherein said annular countersink has a height of from about 0.030 to about 0.115 inches;    an arcuate chuckwall extending radially outward from said annular countersink wherein said arcuate chuckwall has a radius of curvature of from about 0.4 to about 1 inch, the center-point of said radius being located below the profile of said lid, and wherein a line passing through the ends of said arcuate chuckwall is at an angle with respect to said central axis of the center panel of from about 20° to about 80°;    an arcuate step portion extending radially outward from said arcuate chuckwall wherein said arcuate step portion has a radius of curvature of from about 0.02 to about 0.06 inches, the center-point of said radius being located above the profile of said lid;    a transitional portion extending radially outward from said arcuate step portion; and    a peripheral curl portion extending radially outward from said transitional portion wherein said peripheral curl portion has a height less than 0.091 inches.    
     
     
         26 . A method of forming a double seam joining a can body to a can lid, the can lid having a slanted chuckwall at an angle of from about 20° to about 80°, a step portion joining the chuckwall to a transitional portion, and a peripheral curl, and the can body having a can body flange, comprising the steps of: 
 supporting the can body on a base plate;  
 positioning the can lid on the can body with the transitional portion resting on the can body flange;  
 providing a chuck having a lower portion and a substantially cylindrical upper portion, the lower portion configured to closely conform to the chuckwall surface and the surface of the step portion when the chuck is in engagement with the can lid;  
 engaging the can lid with the chuck;  
 rolling the peripheral curl and can body flange together to form an intermediate interlocking peripheral seam; and  
 compressing the intermediate interlocking peripheral seam against the upper portion of the chuck to form a double seam.