Method and apparatus for necking containers

A method of necking an open end of a thin-walled cylindrical container to produce a reduced cylindrical neck merging with a cylindrical side wall through a necked-in portion comprising the steps of engaging an outside surface of the container with a first necking die having a first cylindrical wall surface substantially equal in diameter to said cylindrical side wall and a second cylindrical wall surface of a lesser diameter than said first cylindrical wall surface with an intermediate wall surface between said first and second cylindrical wall surfaces to produce said necked-in portion, said intermediate wall surface having a first arcuate annular surface segment at the end of said first cylindrical wall surface and a second arcuate annular surface segment at the end of said second cylindrical wall surface and engaging an inside surface of said container with a floating form control member including a forming element mounted for radial flowing movement on a body which is mounted for radial floating movement on a support to produce a reduced cylindrical neck that is confined between said first necking die and said form control element to minimize any irregularities in wall thickness and concentricity in said reduced cylindrical neck while a necked-in portion is formed between the side wall and reduced cylindrical neck and has first and second segments between said side wall and said reduced cylindrical neck.

Necking apparatus for producing a reduced cylindrical neck portion and a smooth inwardly-taped necked-in portion adjacent an open end of a metal container side wall comprising a plurality of substantially identical necking turrets respectively rotatable about fixed axes with each turret having a plurality of substantially identical necking substations on the periphery thereof, each necking substation including an annular necking die, a form control member, a container support means spaced from and aligned with said necking die for supporting a container and means on respective turrets for producing relative movement between said necking dies, said form control members in at least a first one of said turrets including a main body mounted for radial movement on a support and forming element mounted for radial floating movement on said main body and engaging an inner surface of said container and the necking dies in said first turret having a first cylindrical surface portion having a diameter substantially equal to the diameter of the container and a second cylindrical surface portion of reduced diameter and a transition surface therebetween to radially compress said metal adjacent said open end and produce a reduced cylindrical neck and a necked-in portion having a first arcuate segment on the end of said reduced cylindrical neck, and in which the necking dies in each of the succeeding turrets have transition surfaces configured to reshape the necked-in portion and increase the axial dimension thereof and have progressively reduced diameter second cylindrical surfaces to progressively decrease the diameter and length of the reduced diameter neck while further compressing the metal therein.