Method and apparatus for forming easy opening container walls

Claim 2

In a method of forming a sheet metal easy opening container end wall having an annular score line therein defining a removable panel, an annular folded band in the removable panel adjacent the score line to shield the raw score edge on the panel after removal from the end wall, an upstanding chuckwall around the removable panel and a peripheral flange extending outwardly from the chuckwall for securement of the end wall to a container body, the steps comprising: drawing the center portion of a generally circular sheet metal blank downwardly with respect to the peripheral edge portions of the blank, drawing an annular U-shaped groove in the blank around the periphery of the center portion of the blank, forming an annular lip and an upstanding chuckwall around the outer edge of the groove, depressing the center portion of the blank and the inner wall of the groove to move portions of the groove radially outwardly to form a Z-wall connecting the center portion of the blank to the lip of the blank, forming a score line in the lip around the blank and collapsing the Z-wall to form an annular folded band adjacent the score line.

Claim 3

A method as set forth in claim 1 in which the blank has a plastic coating on the surface thereof which is to be the inside surface of the can end.

Claim 4

A method as set forth in claim 1 in which the annular band is formed closely adjacent the score line and has a smooth outer edge which projects radially outward beyond the score line.

Claim 5

A method as set forth in claim 3 in which the score line is cut in the outer surface of the lip around the complete circumference of the can end to define a relative large panel which is completely removable from the can end.

Claim 6

In a method for forming a sheet metal easy opening container end wall having an annular score line therein defining a removable panel, an annular folded band in the removable panel adjacent the score line to shield the raw score edge on the panel after removal from the end wall, an upstanding chuckwall around the removable panel and a peripheral flange extending outwardly from the chuckwall for securement of the end wall to a container body, the steps comprising: providing a first die set including a substantially planar first surface perpendicular to the direction of die travel, an annular groove around said planar surface, an annular rim surface around the outer edge of the groove, an annular radially inwardly facing wall surface around the outer edge of the rim surface substantially perpendicular to said first surface and an annular shoulder around the top of said wall surface, and a second opposing die set including a punch having an annular projecting tongue mating with said groove in said first die set, an annular forming ring around said punch including a planar rim surface in opposed relation to said rim surface of said first die set and annular radially outwardly facing wall surface in parallel radially inwardly spaced relation to said wall surface of said first die, and a clamping ring around said forming ring in opposed relation to said shoulder of said first die set; drawing a generally circular blank of sheet of metal between said first and second die sets to form an end shell by moving said punch in said second die set against said first die set with the peripheral edge portions of the blank frictionally restrained between said shoulder and said clamping ring of said first and second die sets respectively to draw the center portion of the blank downwardly with respect to the peripheral edge portion thereof and draw a groove in the blank around the center portion, and thereafter moving the forming ring on said second die set against the annular rim and wall surfaces on said first die set to form a substantially planar lip and upstanding chuckwall around the outer edge of the groove which is formed in the end shell; reforming the end shell by providing support under the lip on the shell and depressing the center portion of the shell within the outline of the groove therein to move portions of the groove in the shell radially outward and thereby form a Z-wall connecting the center portion of the lip in the shell; forming a score line in the lip to define a removable panel; and collapsing the Z-wall to form an annular folded band adjacent the score line.

Claim 7

In a method for forming a sheet metal easy opening container end wall having an annular score line therein defining a removable panel, an annular folded band in the removable panel adjacent the score line to shield the raw score edge on the panel after removal from the end wall, an upstanding chuckwall around the removable panel and a peripheral flange extending outwardly from the chuckwall for securement of the end wall to a container body, the steps comprising: providing a first die set including a substantially planar first surface perpendicular to the direction of die travel, an annular groove around said planar surface, an annular rim surface around the outer edge of the groove, an annular radially inwardly facing wall surface around the outer edge of the rim surface substantially perpendicular to said first surface and an annular shoulder around the top of said wall surface, and a second opposing die set including a punch having an annular projecting tongue mating with said groove in said first die set, an annular forming ring around said punch including a planar rim surface in opposed relation to said rim surface of said first die set and annular radially outwardly facing wall surface in parallel radially inwardly spaced relation to said wall surface of said first die, and a clamping ring around said forming ring in opposed relation to said shoulder of said first die set; drawing a generally circular blank of sheet of metal between said first and second die sets to form an end shell by moving said punch in said second die set against said first die set with the peripheral edge portions of the blank frictionally restrained between said shoulder and said clamping ring of said first and second die sets respectively to draw the center portion of the blank downwardly with respect to the peripheral edge portion thereof and draw a groove in the blank around the center portion, and thereafter moving the forming ring on said second die set against the annular rim and wall surfaces on said first die set to form a substantially planar lip and upstanding chuckwall around the outer edge of the groove which is formed in the end shell; reforming the end shell by providing support under the lip on the shell and depressing the center portion of the shell within the outline of the groove therein to move portions of the groove in the shell radially outward and thereby form a Z-wall connecting the center portion of the lip in the shell; forming a score line in the lip to define a removable panel; and collapsing the Z-wall to form an annular folded band adjacent the score line.

Claim 8

A method as set forth in claim 5 in which the annular groove in the first die set has rounded corners leading into the die surfaces on either side of the groove and the projecting tongue on the second die set has a rounded nose to avoid damage to the blank or a protective coating on the blank.

Claim 9

A method as set forth in claim 5 in which the punch in the second die set includes springs for resiliently supporting it on the punch holder.

Claim 10

In a method of forming a sheet metal easy opening container end wall having an annular score line therein defining a removable panel, an annular folded band in the container wall adjacent the score line to shield the raw score edge after severance of the removable panel from the end wall, an upstanding chuckwall around the end wall and a peripheral flange extending outwardly from the chuckwall for securement of the end wall to a container body, the steps comprising: drawing the center portion of a generally circular sheet metal blank downwardly with respect to the peripheral edge portions of the blank, drawing an annular U-shaped groove in the blank around the periphery of the center portion of the blank, forming an annular lip and an upstanding chuckwall around the outer edge of the groove, depressing the center portion of the blank and the inner wall of the groove to move portions of the groove radially outward and collapsing the groove to form an annular folded band around the center portion of the blank.

Claim 11

In a method of forming a sheet metal easy opening container end wall having an annular score line therein defining a removable panel, an annular folded band in the container wall adjacent the score line to shield the raw score edge after severance of the removable panel from the end wall, an upstanding chuckwall around the end wall and a peripheral flange extending outwardly from the chuckwall for securement of the end wall to a container body, the steps comprising: drawing the center portion of a generally circular sheet metal blank downwardly with respect to the peripheral edge portions of the blank, drawing an annular U-shaped groove in the blank around the periphery of the center portion of the blank, forming an annular lip and an upstanding chuckwall around the outer edge of the groove, depressing the center portion of the blank and the inner wall of the groove to move portions of the groove radially outward and collapsing the groove to form an annular folded band around the center portion of the blank.

Claim 12

A method as set forth in claim 8 in which the blank has a plastic coating on the surface thereof which is to be the inside surface of the can end.

Claim 13

A method as set forth in claim 8 in which the annular band is formed closely adjacent the score line and has a smooth outer edge which projects radially outward beyond the score line.

Claim 14

A method as set forth in claim 10 in which the score line is cut in the outer surface of the lip around the complete circumference of the can end to define a relative large panel which is completely removable from the can end.

Claim 15

In a method for forming a sheet metal easy opening container end wall having an annular score line therein defining a removable panel, an annular folded band in the removable panel adjacent the score line to shield the raw score edge on the panel upon rupture of the score line, an upstanding chuckwall around the removable panel and a peripheral flange extending outwardly from the chuckwall for securement of the end wall to a container body, the steps comprising: providing a first die set including a substantially planar first surface perpendicular to the direction of die travel, an annular groove around said planar surface, an annular rim surface around the outer edge of the groove, an annular radially inwardly facing wall surface around the outer edge of the rim surface substantially perpendicular to said first surface and an annular shoulder around the top of said wall surface, and a second opposing die set including a punch having an annular projecting tongue mating with said groove in said first die set, an annular forming ring around said punch including a planar rim surface in opposed relation to said rim surface of said first die set and annular radiallY outwardly facing wall surface in parallel radially inwardly spaced relation to said wall surface of said first die, and a clamping ring around said forming ring in opposed relation to said shoulder of said first die set; drawing a generally circular blank of sheet of metal between said first and second die sets to form an end shell by moving said punch in said second die set against said first die set with the peripheral edge portions of the blank frictionally restrained between said shoulder and said clamping ring of said first and second die sets respectively to draw the center portion of the blank downwardly with respect to the peripheral edge portion thereof and draw a groove in the blank around the center portion, and thereafter moving the forming ring on said second die set against the annular rim and wall surfaces on said first die set to form a substantially planar lip and upstanding chuckwall around the outer edge of the groove which is formed in the end shell; forming a score line in the lip to define a removable panel in the end shell; depressing the center portion of the shell to move portions of the groove radially outward; and collapsing the groove to form an annular folded band around the removable panel adjacent the score line.

Claim 16

In a method for forming a sheet metal easy opening container end wall having an annular score line therein defining a removable panel, an annular folded band in the removable panel adjacent the score line to shield the raw score edge on the panel upon rupture of the score line, an upstanding chuckwall around the removable panel and a peripheral flange extending outwardly from the chuckwall for securement of the end wall to a container body, the steps comprising: providing a first die set including a substantially planar first surface perpendicular to the direction of die travel, an annular groove around said planar surface, an annular rim surface around the outer edge of the groove, an annular radially inwardly facing wall surface around the outer edge of the rim surface substantially perpendicular to said first surface and an annular shoulder around the top of said wall surface, and a second opposing die set including a punch having an annular projecting tongue mating with said groove in said first die set, an annular forming ring around said punch including a planar rim surface in opposed relation to said rim surface of said first die set and annular radiallY outwardly facing wall surface in parallel radially inwardly spaced relation to said wall surface of said first die, and a clamping ring around said forming ring in opposed relation to said shoulder of said first die set; drawing a generally circular blank of sheet of metal between said first and second die sets to form an end shell by moving said punch in said second die set against said first die set with the peripheral edge portions of the blank frictionally restrained between said shoulder and said clamping ring of said first and second die sets respectively to draw the center portion of the blank downwardly with respect to the peripheral edge portion thereof and draw a groove in the blank around the center portion, and thereafter moving the forming ring on said second die set against the annular rim and wall surfaces on said first die set to form a substantially planar lip and upstanding chuckwall around the outer edge of the groove which is formed in the end shell; forming a score line in the lip to define a removable panel in the end shell; depressing the center portion of the shell to move portions of the groove radially outward; and collapsing the groove to form an annular folded band around the removable panel adjacent the score line.

Claim 17

A method as set forth in claim 12 in which the annular groove in the first die set has rounded corners leading into the die surfaces on either side of the groove and the projecting tongue on the second die set has a rounded nose to avoid damage to the blank or a protective coating on the blank.

Claim 18

A method as set forth in claim 12 in which the punch in the second die set includes springs for resiliently supporting it on the punch holder.