Patent ID: 7819275

Claim:
A one-piece sheet metal can shell having a vertical center axis and a curled peripheral crown adapted to be double-seamed to an end portion of a formed sheet metal can body, said shell comprising a horizontal circular center panel connected in axial cross-section by an inclined panel wall and a vertical wall portion to a curved inner wall portion of a countersink having an inclined outer wall portion and a generally U-shaped cross-sectional configuration, said inclined panel wall having inner and outer surfaces each being straight in axial cross-section and extending from said center panel to said vertical wall portion at an angle between 30° and 60° relative to said center axis, a chuckwall having an inclined straight lower wall portion extending at a first angle from said outer wall portion of said countersink and a curved upper wall portion extending upwardly and laterally outwardly from said lower wall portion and connected to an inclined inner wall portion of said crown through a junction, said upper wall portion of said chuckwall connected to said lower wall portion of said chuckwall by a break forming wall portion, said junction and said break forming wall portion forming end points for said curved upper wall portion of said chuckwall with a straight line connecting said end points defining a second angle in axial cross-section greater than said first angle in axial cross-section, said inclined inner wall portion of said crown extending from said junction at a third angle less than said second angle and less than 16° in axial cross-section, said upper wall portion of said chuckwall projecting substantially above said center panel and having a horizontal radial width from said junction to said break forming wall portion greater than a horizontal radial width from said outer wall portion of said countersink adjacent the bottom of said countersink to said vertical wall portion, and a radial width from said junction to said outer wall portion of said countersink adjacent the bottom of said countersink being greater than a radial width from said break forming wall portion to said vertical wall portion extending to said countersink.