Structure and method facilitating stripping of seamless can body from ironing mandrel
AssigneeNational Steel Corporation
InventorWilliam T. Saunders
Life of this patent
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Abstract
In the manufacture of drawn and ironed, unitary, can bodies, structure and method which interrupt surface contact between an ironing mandrel and the interior sidewall of a can body being ironed to reduce friction for removal of the ironed can body from the mandrel. During passage through an ironing ring, sidewall metal is moved into a narrow-width, linearly-extended indentation in the mandrel sidewall. The metal of the protrusion thus formed on the interior surface of the can body is moved along the mandrel sidewall during passage through a subsequent ironing ring, with such movement breaking surface adhesion between the mandrel sidewall and the interior surface of the container body sidewall to facilitate removal.
Claims8
Structure for use in an ironing process in which the sidewall sheet metal of a seamless, unitary, cup-shaped article is reduced in thickness and elongated by passage of the cup-shaped article, while mounted on a mandrel through a plurality of female, circular, ironing rings of progressively smaller internal diameter, during which passage an intimate surface contact is normally established causing an undesirably tight adherence between the elongated sidewall of the cup-shaped article and the punch,
- such structure facilitating removal of an ironed sidewall cup-shaped article from the mandrel after ironing comprising
- an elongated, generally-cylindrical configuration ironing mandrel having a
- work input end,
- a central longitudinal axis,
- a sidewall radially spaced from the central
- longitudinal axis, and
- a work output end longitudinally opposite to the work input end,
- the mandrel sidewall including indention means and remaining peripheral surface means, the latter being uniformly spaced radially from the central longitudinal axis of the mandrel,
- the indention means comprising a narrow-width, linearly-extended indentation subsurface of the remaining peripheral surface of the mandrel sidewall which is uniformly spaced radially from the central longitudinal axis,
- such indentation extending over a major portion of the mandrel sidewall which is contacted by sheet metal of the cup-shaped article sidewall providing for movement of sidewall sheet metal into such indentation to form a protrusion on the interior surface of the sidewall of the cup-shaped article during passage through an ironing ring and for movement of such protrusion metal along the sidewall of the mandrel during passage through a subsequent ironing ring so as to reduce intimate surface contact between the interior surface of the cup-shaped article and the ironing mandrel to facilitate removal of such cup-shaped article after ironing.
Method for elongating and thinning the sidewall of a seamless, unitary, sheet metal cup-shaped article and facilitating stripping of such elongated sidewall cup-shaped article from an ironing mandrel by modifying the intimate surface contact between article and mandrel normally established during ironing, comprising the steps of
- providing an elongated, generally-cylindrical configuration ironing mandrel having a
- work input end,
- a central longitudinal axis,
- a sidewall radially spaced from the central longitudinal axis, and
- a work output end longitudinally opposite to the work input end,
- the mandrel sidewall including indention means and peripheral surface means, the latter being uniformly spaced radially from the central longitudinal axis,
- the indention means comprising a narrow-width, linearly-extended, indentation, which indentation extends over a major portion of that portion of the mandrel sidewall contacted by sidewall sheet metal of a cup-shaped article being ironed,
- providing a sheet metal cup-shaped article mounted on such mandrel, the cup-shaped article having a bottom wall, unitary sidewall, and an open end longitudinally opposite to such bottom wall,
- the cup-shaped article having a configuration conforming to that of the ironing mandrel,
- moving the mandrel and mounted cup-shaped article through a first, female, circular ironing ring having a central axis coincident with that of the central longitudinal axis of the ironing mandrel,
- such ironing ring having an internal diameter less than the external diameter of the cup-shaped article and greater than that of the peripheral surface of the ironing mandrel such that sidewall sheet metal of the cup-shaped article is elongated and thinned with sidewall sheet metal being moved into at least a portion of such indentation forming a protrusion in the sheet metal on the interior surface of the cup-shaped article sidewall,
- continuing longitudinal movement of the ironing mandrel and mounted cup-shaped article through a subsequent ironing ring of smaller internal diameter than the first ironing ring so as to move the sheet metal of the cup-shaped article sidewall longitudinally further along the sidewall of the mandrel, including movement of such protrusion metal, formed on the interior surface of the cup-shaped article sidewall, along the mandrel sidewall into contact with the peripheral surface of the mandrel reducing frictional contact between the peripheral surface of the mandrel sidewall and the interior surface of the cup-shaped article to facilitate removal of such cup-shaped article from such mandrel after ironing.
Dependencies are inferred from the claim text.