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US 4,448,322 AGranted
Metal container end
AssigneeNational Can Corporation
InventorJohn L. Kraska
Life of this patent
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AssigneeNational Can Corporation
InventorJohn L. Kraska
Estimating the term…
A container end formed from metal having an approximate thickness of 0.0120 inches which is capable of withstanding at least 90 psi buckle pressure and at least 60 psi rock pressure is disclosed herein. A container end panel includes a peripheral curl surrounding a substantially flat center panel with a countersink therebetween. The countersink has inner and outer substantially flat walls that are interconnected by an arcuate portion that has a radius of approximately 0.030 inches and the inner wall is connected to the periphery of the center panel through an arcuate portion that has a radius of approximately 0.025 inches. The outer flat wall has a length which is greater than the length of the inner flat wall and the outer flat wall defines an angle of less than five degrees with respect to a plane that extends perpendicular through the center flat panel. The inner flat wall has a length to locate the lower edge of the countersink about 0.075 inches or more below the lower edge of the periphery of the center panel and defines a minimum angle with respect to a vertical reference plane.
A circular, metal container end having a metal thickness of approximately 0.0120 inches and including a peripheral curl and a central panel with a countersink between said curl and central panel extending below said central panel, the improvement of said countersink having inner and outer flat walls interconnected by a first arcuate portion, said first arcuate portion having a radius less than three times the thickness of said metal, said flat inner wall being integral with said central panel through a second arcuate portion having a radius approximately twice the thickness of said metal and said outer flat wall having a length greater than said inner flat wall so that an upper end is located above a peripheral edge of said central panel, and said outer flat wall defining an angle of less than five degrees with respect to a plane extending perpendicular to said central panel, said peripheral curl extending above said central panel so that said container end is capable of resisting at least 90 psi buckle pressure and at least 60 psi rock pressure.
Dependencies are inferred from the claim text.