Method for necking thin wall metallic containers

Claim 1

A method of forming at least two reduced diameter portions in a drawn and ironed seamless body having a cylindrically shaped sidewall, an internally formed bottom and an open end, said method comprising deflecting inwardly the open end of the body into contact with first die forming means including a supporting bore with a curvilinear transition portion leading into a necking bore, said supporting bore conforming substantially to the external diameter of the body, said deflecting inwardly causing a reduction in the diameter of the open end on the order of about 3.5 percent to about 3.8 percent over a predetermined length, further deflecting inwardly the reduced open end only over the same predetermined length by a second die forming means to further reduce the diameter of the reduced open end, said second die forming means including a second supporting bore with a second curvilinear transition portion leading into a second necking bore, said second curvilinear transition portion contacting directly and turning the open end of the body along a sloping surface to redeflect the previous diameter formed by the first inward deflection and bringing the previous diameter into conformity with the entire second die forming means, the second deflection reducing the diameter along the predetermined length on the order of between about 1.69 percent to about 1.7 percent, and thereafter deflecting inwardly in a final stage a length less than the predetermined length by a third die forming means comprising a short supporting portion conterminous with a short transition portion leading into a short necking bore, said further reduced open end being brought into comformity with the short supporting portion, transition portion and necking bore to reduce the final diameter thereof on the order of between about 3.8 to about 4.1 percent.

Claim 2

A method of forming at least two reduced diameter portions in a drawn and ironed seamless body having a cylindrically shaped sidewall, an internally formed bottom and an open end, said method comprising deflecting inwardly the open end of the body into contact with first die forming means including a supporting bore with a curvilinear transition portion leading into a necking bore, said supporting bore conforming substantially to the external diameter of the body, said deflecting inwardly causing a reduction in the diameter of the open end on the order of about 3.5 percent to about 3.8 percent over a predetermined length, further deflecting inwardly the reduced open end only over the same predetermined length by a second die forming means to further reduce the diameter of the reduced open end, said second die forming means including a second supporting bore with a second curvilinear transition portion leading into a second necking bore, said second curvilinear transition portion contacting directly and turning the open end of the body along a sloping surface to redeflect the previous diameter formed by the first inward deflection and bringing the previous diameter into conformity with the entire second die forming means, the second deflection reducing the diameter along the predetermined length on the order of between about 1.69 percent to about 1.7 percent, and thereafter deflecting inwardly in a final stage a length less than the predetermined length by a third die forming means comprising a short supporting portion conterminous with a short transition portion leading into a short necking bore, said further reduced open end being brought into comformity with the short supporting portion, transition portion and necking bore to reduce the final diameter thereof on the order of between about 3.8 to about 4.1 percent.

Claim 6

A method for producing a reduced diameter opening proximal to one end of a drawn and ironed seamless container of the type having a cylindrically shaped wall that is metallic and that is less than 0.010 inches thick, by producing a first reduced diameter portion that is disposed proximal to an open end of said container and by producing a first curvilinear transition portion that is disposed intermediate of and juxtaposed against both the remainder of said cylindrically shaped wall and said reduced diameter portion, and for minimizing the number of forming steps, which method comprises forming a temporary reduced diameter portion that is proximal to said open end of said container and that comprises a smaller percentage of diametral reduction in said cylindrically shaped wall than that which would result in localized buckling in said temporary reduced diameter portion, and forming a temporary curvilinear transition portion that is disposed intermediate of said temporary reduced diameter portion and said remainder of said cylindrically shaped wall, in a first step said forming of said diameter and transition portions being over a predetermined length; and reforming said temporary reduced diameter portion by a percentage reduction that is less than 65 percent of the percentage reduction of said first step to form a first reduced diameter portion, and reforming said temporary curvilinear transition portion to form a first curvilinear transition portion that blends said reformed reduced diameter portion into said remainder of said cylindrically shaped wall, said reforming of said diameter and transition in a second step portions being over the same predetermined length.

Claim 7

A method for producing a reduced diameter opening proximal to one end of a drawn and ironed seamless container of the type having a cylindrically shaped wall that is metallic and that is less than 0.010 inches thick, by producing a first reduced diameter portion that is disposed proximal to an open end of said container and by producing a first curvilinear transition portion that is disposed intermediate of and juxtaposed against both the remainder of said cylindrically shaped wall and said reduced diameter portion, and for minimizing the number of forming steps, which method comprises forming a temporary reduced diameter portion that is proximal to said open end of said container and that comprises a smaller percentage of diametral reduction in said cylindrically shaped wall than that which would result in localized buckling in said temporary reduced diameter portion, and forming a temporary curvilinear transition portion that is disposed intermediate of said temporary reduced diameter portion and said remainder of said cylindrically shaped wall, in a first step said forming of said diameter and transition portions being over a predetermined length; and reforming said temporary reduced diameter portion by a percentage reduction that is less than 65 percent of the percentage reduction of said first step to form a first reduced diameter portion, and reforming said temporary curvilinear transition portion to form a first curvilinear transition portion that blends said reformed reduced diameter portion into said remainder of said cylindrically shaped wall, said reforming of said diameter and transition in a second step portions being over the same predetermined length.

Claim 8

A method for producing a reduced diameter opening proximal to an open end of a drawn and ironed seamless container, of the type that has a cylindrically shaped wall that is metallic and that is less than 0.010 inches thick, by necking down a portion of said wall to provide at least one reduced diameter portion and to provide at least one curvilinear transition portion that is intermediate of said reduced diameter portion and the remainder of said cylindrically shaped wall, and for achieving the greatest percentage of diametral reduction of said reduced diameter opening with the fewest number of forming steps while minimizing the total number of said reduced diameter portion and the total number of said curvilinear transition portions, which method comprises forming a temporary reduced diameter portion that is at least 3.0 percent smaller than the diameter of said cylindrically shaped wall, and forming a temporary curvilinear transition portion that is disposed intermediate of the temporary reduced diameter portion and said remainder of said cylindrically shaped wall, said forming of said diameter and transition portions being over a predetermined length in a first step; and reforming said temporary reduced diameter portion into a first reduced diameter portion by reducing said temporary reduced diameter portion by at least 1.5 percent, and reforming said curvilinear transition portion to blend said first reduced diameter portion into said remainder of said cylindrically shaped wall, said reforming of said diameter and transition portions being over the same predetermined length, in a second step.

Claim 9

A method for producing a reduced diameter opening proximal to an open end of a drawn and ironed seamless container, of the type that has a cylindrically shaped wall that is metallic and that is less than 0.010 inches thick, by necking down a portion of said wall to provide at least one reduced diameter portion and to provide at least one curvilinear transition portion that is intermediate of said reduced diameter portion and the remainder of said cylindrically shaped wall, and for achieving the greatest percentage of diametral reduction of said reduced diameter opening with the fewest number of forming steps while minimizing the total number of said reduced diameter portion and the total number of said curvilinear transition portions, which method comprises forming a temporary reduced diameter portion that is at least 3.0 percent smaller than the diameter of said cylindrically shaped wall, and forming a temporary curvilinear transition portion that is disposed intermediate of the temporary reduced diameter portion and said remainder of said cylindrically shaped wall, said forming of said diameter and transition portions being over a predetermined length in a first step; and reforming said temporary reduced diameter portion into a first reduced diameter portion by reducing said temporary reduced diameter portion by at least 1.5 percent, and reforming said curvilinear transition portion to blend said first reduced diameter portion into said remainder of said cylindrically shaped wall, said reforming of said diameter and transition portions being over the same predetermined length, in a second step.

Claim 10

A method for producing a first reduced diameter portion of more than 4.8 percent diametral reduction proximal to an open end of a drawn and ironed seamless container of the type having a cylindrically shaped wall that is metallic and that is less than 0.010 inches thick, and for producing a single curvilinear transition portion between said first reduced diameter cylindrical portion and the remainder of said cylindrically shaped wall in two forming steps, which method comprises forming a temporary reduced diameter portion that is 3.0 to 4.3 percent smaller than said remainder of said cylindrically shaped wall, and forming a temporary curvilinear transition portion that is disposed intermediate of said temporary reduced diameter portion and said remainder of said cylindrically shaped wall, said forming of said diameter and transition portions being over a predetermined length; and forming said first reduced diameter portion and said first curvilinear transition portion by reforming said temporary reduced diameter portion to said more than 4.8 percent diametral reduction than said remainder of said cylindrically shaped wall, and by reforming said temporary curvilinear transition portion into said first curvilinear transition portion, said reforming of said diameter and transition portions being over the same predetermined length.

Claim 11

A method for producing a first reduced diameter portion of more than 4.8 percent diametral reduction proximal to an open end of a drawn and ironed seamless container of the type having a cylindrically shaped wall that is metallic and that is less than 0.010 inches thick, and for producing a single curvilinear transition portion between said first reduced diameter cylindrical portion and the remainder of said cylindrically shaped wall in two forming steps, which method comprises forming a temporary reduced diameter portion that is 3.0 to 4.3 percent smaller than said remainder of said cylindrically shaped wall, and forming a temporary curvilinear transition portion that is disposed intermediate of said temporary reduced diameter portion and said remainder of said cylindrically shaped wall, said forming of said diameter and transition portions being over a predetermined length; and forming said first reduced diameter portion and said first curvilinear transition portion by reforming said temporary reduced diameter portion to said more than 4.8 percent diametral reduction than said remainder of said cylindrically shaped wall, and by reforming said temporary curvilinear transition portion into said first curvilinear transition portion, said reforming of said diameter and transition portions being over the same predetermined length.

Claim 12

A method as claimed in claims 5, 6, or 7 in which said reforming of said temporary reduced diameter portion into said first reduced diameter portion comprises moving said open end of said container and said temporary reduced diameter portion of said container into a supporting bore of a necking die that is substantially the same diameter as said temporary reduced diameter portion, forcing said temporary reduced diameter portion into a necking bore of said necking die to reform said temporary reduced diameter portion into said first reduced diameter portion, and by inserting a punch inside said open end and into said reduced diameter portion to minimize localized wrinkling of said reduced diameter portion during said reforming step.

Claim 13

A method as claimed in claims 5, 6, or 7 in which said wall comprises steel.

Claim 14

A method as claimed in claims 5, 6, or 7 in which said wall comprises aluminum.

Claim 15

A method as claimed in claims 5, 6, or 7 in which said cylindrically shaped wall is less than 0.008 inches thick.