Can end with retort resistant panel, and tooling and associated method for providing same

Abstract

A method of making a can end, which includes a recessed panel defined by an upwardly extending chuck wall, a peripheral scoreline disposed in a public side of the panel proximate to the base of the chuck wall, a tab fastened to the panel by a rivet, includes the step of employing tooling to form a pressure resistance bead extends around the panel inboard of the peripheral scoreline and outboard of the rivet. The tooling forms a saw tooth panel formation proximate to the pressure resistance bead inboard of the pressure resistance bead. Among other benefits, the pressure resistance bead and saw tooth panel formation created by the tooling and method combine to resist wrinkling or other undesired deformation of the can end.

What is claimed is: 
     
         1 . A method for providing a can end, the method comprising:
 providing a recessed panel defined by an upwardly extending chuck wall, the panel having a product side, a public side disposed opposite the product side, a peripheral scoreline disposed in the public side of the panel at or about the base of the chuck wall, and a rivet;   forming a pressure resistance bead in the panel, the pressure resistance bead extending around the panel inboard of the peripheral scoreline and outboard of the rivet; and   forming a saw tooth panel formation proximate to the pressure resistance bead.   
     
     
         2 . The method of  claim 1 , further comprising the panel having a planar portion disposed between the pressure resistance bead and the saw tooth panel formation. 
     
     
         3 . The method of  claim 1 , further comprising the panel having an annular countersink extending upwardly and inwardly from the base of the chuck wall toward the peripheral scoreline. 
     
     
         4 . The method of  claim 1 , further comprising the pressure resistance bead being a downbead extending inwardly from the public side of the panel and outwardly from the product side of the panel. 
     
     
         5 . The method of  claim 1 , further comprising staking the rivet to fasten a tab to the panel. 
     
     
         6 . The method of  claim 5 , further comprising the tab including a nose portion and a lift portion disposed opposite and distal from the nose portion; and wherein the pressure resistance bead passes beneath the nose portion. 
     
     
         7 . The method of  claim 5 , further comprising the saw tooth panel formation beginning proximate to one side of the tab, extending around the panel inboard of the pressure resistance bead, and ending proximate to the opposite side of the tab. 
     
     
         8 . The method of  claim 1 , further comprising:
 providing a tool assembly including a first tool and a second tool disposed opposite the first tool; and   forming the pressure resistance bead by having the first tool cooperate with the second tool.   
     
     
         9 . The method of  claim 8  wherein the first tool comprises a first planar portion, a second planar portion spaced from the first planar portion, and a recess extending inwardly from the first planar portion and the second planar portion; wherein the second tool comprises a protrusion; and wherein the method further comprises extending the protrusion of the second tool into the recess of the first tool to form the pressure resistance bead. 
     
     
         10 . The method of  claim 1 , further comprising:
 providing a tool assembly including a first tool and a second tool disposed opposite the first tool; and   forming the saw tooth panel formation by having the first tool cooperate with the second tool.   
     
     
         11 . The method of  claim 10  wherein the first tool comprises a forming member including a projection, a first planar portion disposed on one side of the projection, and a second planar portion disposed on the opposite side of the projection; wherein the second tool comprises a first member including an offset protrusion; and wherein the method further comprises moving the projection of the first tool toward the first member of the second tool as the offset protrusion of the first member of the second tool moves toward the second planar portion of the first tool, thereby making a plurality of bends in the panel to form the saw tooth panel formation. 
     
     
         12 . The method of  claim 11  wherein the first member includes a first side and a second side disposed opposite and distal from the first side; wherein the second tool further comprises a second member movably disposed on the first side of the first member, and a third member movably disposed on the second side of the first member; wherein the first tool further comprises a supporting member movably disposed beside the forming member; wherein the supporting member includes a shoulder; and wherein the method further comprises:
 forming a first bend of the saw tooth panel formation by having the second member cooperate with the first planar portion of the first tool; 
 forming a second bend of the saw tooth panel formation with the projection of the first tool; 
 forming a third bend of the saw tooth panel formation with the offset protrusion of the first member of the second tool; and 
 having the third member cooperate with the supporting member to support the pressure resistance bead as the shoulder of the supporting member forms a fourth bend of the saw tooth panel formation. 
 
     
     
         13 . The method of  claim 1 , further comprising the panel having a planar portion inboard of the saw tooth panel formation; wherein the planar portion has a depth; wherein the saw tooth panel formation comprises a plurality of bends and a drape defined by the distance between a first one of the bends and a second adjacent one of the bends; and wherein the ratio of the depth of the panel to the drape is from 1:1 to 1:4. 
     
     
         14 . The method of  claim 13 , further comprising forming the drape symmetrically on opposing sides of a peak of the saw tooth panel formation. 
     
     
         15 . The method of  claim 1  wherein the pressure resistance bead has a depth; and wherein the depth is from 0.0060 inch to 0.0200 inch.