Method of making folded can ends and folded can end product

Claim 2

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold by a series of successive drawing, redrawing, resizing, scoring and folding operations in which said successive operations include forming an annular fold panel extending directly between an upper concavely curved corner formed in an axially extending side wall of a cup drawn from a metal blank and a lower curved corner connected with the cup bottom wall; forming an annular upwardly convex shoulder in the fold panel between the upper and lower corners; successively bulging the cup wall portion circumferentially outward between the shoulder and lower corner; successively decreasing the depth of the cup bottom wall below the shoulder; and successively decreasing the radius of curvature of the lower corner in preparation for folding the metal between the shoulder and lower corner to form an annular triple fold-S-shaped in cross section between the shoulder and lower corner.

Claim 3

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold by a series of successive drawing, redrawing, resizing, scoring and folding operations in which said successive operations include forming an annular fold panel extending directly between an upper concavely curved corner formed in an axially extending side wall of a cup drawn from a metal blank and a lower curved corner connected with the cup bottom wall; forming an annular upwardly convex shoulder in the fold panel between the upper and lower corners; successively bulging the cup wall portion circumferentially outward between the shoulder and lower corner; successively forming a curved corner radius at the underside of the shoulder with a radius of curvature decreasing in size to provide a pivot point from which the metal between the shoulder and lower corner is folded to form an annular triple fold S-shaped in cross section, and then folding the metal by pressure applied to the shoulder to move the shoulder toward the cup bottom wall.

Claim 4

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold by a series of successive drawing, redrawing, resizing, scoring and folding operations in which said successive operations include forming an annular fold panel extending directly between an upper concavely curved corner formed in an axially extending side wall of a cup drawn from a metal blank and a lower curved corner connected with the cup bottom wall; forming an annular upwardly convex shoulder in the fold panel between the upper and lower corners; successively bulging the cup wall portion circumferentially outward between the shoulder and lower corner; successively forming a curved corner radius at the underside of the shoulder with a radius of curvature decreasing in size to provide a pivot point from which the metal between the shoulder and lower corner is folded to form an annular triple fold S-shaped in cross section, and then folding the metal by pressure applied to the shoulder to move the shoulder toward the cup bottom wall.

Claim 5

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold by a series of successive drawing, redrawing, resizing, scoring and folding operations in which said successive operations include forming an annular fold panel extending directly between an upper concavely curved corner formed in an axially extending side wall of a cup drawn from a metal blank and a lower curved corner connected with the cup bottom wall; forming an annular upwardly convex shoulder in the fold panel between the upper and lower corners; successively bulging the cup wall portion circumferentially outward between the shoulder and lower corner; and coining an annular zone of metal located between the upper corner and shoulder during one of the bulging operations.

Claim 6

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold by a series of successive drawing, redrawing, resizing, scoring and folding operations in which said successive operations include forming an annular fold panel extending directly between an upper concavely curved corner formed in an axially extending side wall of a cup drawn from a metal blank and a lower curved corner connected with the cup bottom wall; forming an annular upwardly convex shoulder in the fold panel between the upper and lower corners; successively bulging the cup wall portion circumferentially outward between the shoulder and lower corner; and coining an annular zone of metal located between the upper corner and shoulder during one of the bulging operations.

Claim 7

The method defined in claim 3 in which the metal in the coined annular area between the upper corner and shoulder is scored with an annular score line during the second of the successive bulging operations.

Claim 8

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold by a series of successive drawing, redrawing, resizing, scoring and folding operations in which said successive operations include forming an annular fold panel extending directly between an upper concavely curved corner formed in an axially extendinG the side wall of a cup drawn from a metal blank and a lower curved corner connected with the cup bottom wall; forming an annular upwardly convex shoulder in the fold panel between the upper and lower corners; successively bulging the cup wall portion circumferentially outward between the shoulder and lower corner; successively forming a curved corner radius at the underside of the shoulder with a radius of curvature decreasing in size to provide a pivot point from which the metal between the shoulder and lower corner is folded to form an annular triple fold S-shaped in cross section; coining an annular zone of metal located between the upper corner and shoulder during one of the bulging operations; scoring the metal in the coined annular zone between the upper corner and shoulder with an annular score line during the second of the successive bulging operations; successively decreasing the depth of the cup bottom wall below the shoulder; successively decreasing the radius of curvature of the lower corner in preparation for folding metal between the shoulder and lower corner to form an annular triple fold S-shaped in cross section between the shoulder and lower corner; and then folding the metal by pressure applied to the shoulder to move the shoulder toward the cup bottom wall.

Claim 9

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold by a series of successive drawing, redrawing, resizing, scoring and folding operations in which said successive operations include forming an annular fold panel extending directly between an upper concavely curved corner formed in an axially extendinG the side wall of a cup drawn from a metal blank and a lower curved corner connected with the cup bottom wall; forming an annular upwardly convex shoulder in the fold panel between the upper and lower corners; successively bulging the cup wall portion circumferentially outward between the shoulder and lower corner; successively forming a curved corner radius at the underside of the shoulder with a radius of curvature decreasing in size to provide a pivot point from which the metal between the shoulder and lower corner is folded to form an annular triple fold S-shaped in cross section; coining an annular zone of metal located between the upper corner and shoulder during one of the bulging operations; scoring the metal in the coined annular zone between the upper corner and shoulder with an annular score line during the second of the successive bulging operations; successively decreasing the depth of the cup bottom wall below the shoulder; successively decreasing the radius of curvature of the lower corner in preparation for folding metal between the shoulder and lower corner to form an annular triple fold S-shaped in cross section between the shoulder and lower corner; and then folding the metal by pressure applied to the shoulder to move the shoulder toward the cup bottom wall.

Claim 10

The method defined in claim 1 in which the operation of forming the annular fold panel includes the steps of forming a conical annular band extending directly between an upper concavely curved corner formed in an axially extending side wall of a cup drawn from a metal blank and a lower curved corner connected with the cup bottom wall; and then redrawing the blank to reform the metal in the conical annular band to provide a rounded shoulder having upper convex and lower concave surfaces in cross section intermediate the upper and lower corners connected with the upper corner by an annular horizontal portion extending inward from said upper corner and connected with the lower corner by a downwardly inwardly tapered band portion.

Claim 11

The method defined in claim 6 which includes the step of coining the metal in the annular zone of said horizontally extending portion located inward of the upper corner at the same time that the first of the successive bulging operations is performed.

Claim 12

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold by a series of successive drawing, redrawing, resizing, socring and folding operations in which said successive operations include forming an annular fold panel extending directly between an upper concavely curved corner formed in an axially extending side wall of a cup drawn from a metal blank and a lower curved corner connected with the cup bottom wall; forming an annular upwardly convex shoulder in the fold panel between the upper and lower corners; successively bulging the cup wall portion circumferentially outward between the shoulder and lower corner; coining an annular zone of metal located between the upper corner and shoulder during one of the bulging operations; and forming the inner annular edge of the coined annular zone to define a break point located radially inward of the outer surface of the outward bulge formed by the one bulging operation.

Claim 13

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold by a series of successive drawing, redrawing, resizing, socring and folding operations in which said successive operations include forming an annular fold panel extending directly between an upper concavely curved corner formed in an axially extending side wall of a cup drawn from a metal blank and a lower curved corner connected with the cup bottom wall; forming an annular upwardly convex shoulder in the fold panel between the upper and lower corners; successively bulging the cup wall portion circumferentially outward between the shoulder and lower corner; coining an annular zone of metal located between the upper corner and shoulder during one of the bulging operations; and forming the inner annular edge of the coined annular zone to define a break point located radially inward of the outer surface of the outward bulge formed by the one bulging operation.

Claim 14

The method defined in claim 8 in which the coined metal in the annular zone is scored to form an annular scored tear line located radially outward of said break point.

Claim 15

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold by a series of successive drawing, redrawing, resizing, scoring and folding operations in which said successive operations include forming an annular fold panel extending directly between an upper concavely curved corner formed in an axially extending sidE wall of a cup drawn from a metal blank and a lower curved corner connected with the cup bottom wall; forming an annular upwardly convex shoulder in the fold panel between the upper and lower corners; successively bulging the cup wall portion circumferentially outward between the shoulder and lower corner; successively forming a curved corner radius in the underside of the shoulder with the radius of curvature decreasing in size to provide a pivot point from which the metal between the shoulder and lower corner is folded to form annular triple fold S-shaped in cross section; coining an annular zone of metal located between the upper corner and shoulder during one of the bulging operations; forming the inner annular edge of the coined annular zone to define a break point located radially inward of the outer surface of the outward bulge during one of the bulging operations; scoring the coined metal in the annular zone to form an annular scored tear line on the coined surface located radially outward of said break and pivot points during the second of the successive bulging operations; locating the break and pivot points radially inward of the bulge formed by the second of the successive bulging operations; and then folding the metal by pressure applied to the shoulder to move the shoulder toward the cup bottom wall.

Claim 16

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold by a series of successive drawing, redrawing, resizing, scoring and folding operations in which said successive operations include forming an annular fold panel extending directly between an upper concavely curved corner formed in an axially extending sidE wall of a cup drawn from a metal blank and a lower curved corner connected with the cup bottom wall; forming an annular upwardly convex shoulder in the fold panel between the upper and lower corners; successively bulging the cup wall portion circumferentially outward between the shoulder and lower corner; successively forming a curved corner radius in the underside of the shoulder with the radius of curvature decreasing in size to provide a pivot point from which the metal between the shoulder and lower corner is folded to form annular triple fold S-shaped in cross section; coining an annular zone of metal located between the upper corner and shoulder during one of the bulging operations; forming the inner annular edge of the coined annular zone to define a break point located radially inward of the outer surface of the outward bulge during one of the bulging operations; scoring the coined metal in the annular zone to form an annular scored tear line on the coined surface located radially outward of said break and pivot points during the second of the successive bulging operations; locating the break and pivot points radially inward of the bulge formed by the second of the successive bulging operations; and then folding the metal by pressure applied to the shoulder to move the shoulder toward the cup bottom wall.

Claim 17

The method defined in claim 1 including the steps during the successive shoulder forming and bulging operations of forming and reforming a rivet bubble adjacent the lower curved corner.

Claim 18

The method defined in claim 11 in which the rivet bubble is initially formed during the step of forming the annular upwardly convex shoulder in the fold panel, and in which the rivet bubble is reformed during one of the bulging operations.

Claim 19

The method defined in claim 12 in which an area adjacent the reformed rivet bubble and between the rivet bubble and bulged blank portion is coined during the reforming of the rivet bubble.

Claim 20

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold which includes the steps of drawing a sheet metal blank to form a primary cup shape having cup bottom, side and open end flange walls, and forming a conical annular band connected with the cup side and bottom walls directly by concave curved upper and concave curved lower corners; curling the open end cup flange wall; redrawing the blank to form a rounded shoulder in said conical band having upper convex and lower concave surfaces in cross section intermediate the upper and lower corners; resizing the redrawn blank and coining metal in an annular zone located between the upper corner and shoulder and outwardly bulging the metal between the shoulder and lower corner while decreasing the curvature of the lower concave surface of said shoulder to form a pivot point; scoring a continuous score line in the coined annular zone and further bulging the blank metal between the shoulder and lower corner; and then folding the bulged metal between the shoulder and lower corner to form a continuous annular triple layer fold generally S-shaped in cross section continuously around the blank with the scored coined annular zone located in the upper fold layer and above the two lower fold layers.

Claim 21

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold which includes the steps of drawing a sheet metal blank to form a primary cup shape having cup bottom, side and open end flange walls, and forming a conical annular band connected with the cup side and bottom walls directly by concave curved upper and concave curved lower corners; curling the open end cup flange wall; redrawing the blank to form a rounded shoulder in said conical band having upper convex and lower concave surfaces in cross section intermediate the upper and lower corners; resizing the redrawn blank and coining metal in an annular zone located between the upper corner and shoulder and outwardly bulging the metal between the shoulder and lower corner while decreasing the curvature of the lower concave surface of said shoulder to form a pivot point; scoring a continuous score line in the coined annular zone and further bulging the blank metal between the shoulder and lower corner; and then folding the bulged metal between the shoulder and lower corner to form a continuous annular triple layer fold generally S-shaped in cross section continuously around the blank with the scored coined annular zone located in the upper fold layer and above the two lower fold layers.

Claim 22

The method defined in claim 14 including the further steps of forming a rivet bubble in the cup shape blank adjacent the lower corner, assembling a pull tab to said rivet bubble after the folding operation has been completed, and assembling and staking a pull ring to the rivet bubble.

Claim 23

The method defined in claim 15 in which the pull ring is formed with a nose and is located with the pull ring longitudinal axis extending radially of the can end through the center of the staked rivet and nose.

Claim 24

The method defined in claim 16 including the steps of locating the pull ring nose above the triple fold; and forming the triple fold With a greater thickness in a predetermined arc extending from either side of the nose around the can end, than the thickness of the remainder of the arucate extent of the continuous triple fold.

Claim 25

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold, which includes the steps of drawing a cup shape having cup bottom and side walls, and forming a conical annular fold panel band connected with the cup side and bottom walls directly by concave curved upper and concave curved lower corners; forming a shoulder having upper convex and lower concave surfaces in cross section in the fold panel intermediate the upper and lower corners; and successively bulging areas of the fold panel between the shoulder and lower corner, and coining and scoring to the areas between the shoulder and upper corner in preparation for folding the metal between the shoulder and lower corner to form a triple fold.

Claim 26

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold, which includes the steps of drawing a cup shape having cup bottom and side walls, and forming a conical annular fold panel band connected with the cup side and bottom walls directly by concave curved upper and concave curved lower corners; forming a shoulder having upper convex and lower concave surfaces in cross section in the fold panel intermediate the upper and lower corners; and successively bulging areas of the fold panel between the shoulder and lower corner, and coining and scoring to the areas between the shoulder and upper corner in preparation for folding the metal between the shoulder and lower corner to form a triple fold.

Claim 27

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold, which includes the steps of drawing a cup shape having cup bottom and side walls, and forming a conical annular fold panel band connected with the cup side and bottom walls directly by concave curved upper and concave curved lower corners; forming a shoulder having upper convex and lower concave surfaces in cross section in the fold panel; forming bulged walls in the fold panel below the shoulder; coining metal in an annular zone outward of the shoulder to form break and pivot points in the regions respectively of the upper convex and lower concave surfaces of the shoulder; forming a continuous annular score line in the coined metal; locating the pivot point radially inward of the bulged outer surface; and folding the bulged surface about the pivot point by pressure applied to the shoulder to move the shoulder toward the cup bottom wall.

Claim 28

In a method of cold working a sheet metal blank to form a can end member having a recessed end panel extending from a recessed corner and connected with the corner by an annularly scored protective metal triple fold, which includes the steps of drawing a cup shape having cup bottom and side walls, and forming a conical annular fold panel band connected with the cup side and bottom walls directly by concave curved upper and concave curved lower corners; forming a shoulder having upper convex and lower concave surfaces in cross section in the fold panel; forming bulged walls in the fold panel below the shoulder; coining metal in an annular zone outward of the shoulder to form break and pivot points in the regions respectively of the upper convex and lower concave surfaces of the shoulder; forming a continuous annular score line in the coined metal; locating the pivot point radially inward of the bulged outer surface; and folding the bulged surface about the pivot point by pressure applied to the shoulder to move the shoulder toward the cup bottom wall.

Claim 29

The method defined in claim 19 in which the folding of the bulged surface about the pivot point forms a continuous annular triple fold generally S-shaped in cross section between the shoulder and lower corner; and in which the triple fold is formed with a greater thickness in a predetermined arc thereof than the thickness of the remaining arcuate extent of the continuous annular triple fold.

Claim 30

The method defined in claim 2 in which the folding of the metal by pressure applied to the shoulder forms a continuous annular triple fold generally S-shaped in cross section between the shoulder and lower corner; and in which the triple fold is formed with a greater thickness in a predetermined arc thereof than the thickness of the remaining arcuate extent of the continuous annular triple fold.

Claim 31

The method defined in claim 1 in which the operations of forming the annular fold panel and convex shoulder include the steps of forming a conical annular band extending directly between the upper and lower corners, and then redrawing the blank to reform the metal in the conical annular band to provide the upwardly convex shoulder in the fold panel between the upper and lower corners; in which after the successive decrease of lower corner curvature, the metal is folded between the shoulder and lower corner by pressure applied to the shoulder to move the shoulder toward the cup bottom wall to form a continuous annular triple fold generally S-shaped in cross section between the shoulder and upper corner; and in which the triple fold is formed with a greater thickness in a predetermined arc thereof than the thickness of the remaining arcuate extent of the continuous annular triple fold.