US 5,626,049 AGranted

Draw-process systems for fabricating one-piece can bodies

AssigneeWeirton Steel Corporation

InventorWilliam T. Saunders

Life of this patent

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Abstract

Draw processing flat-rolled sheet metal substrate preselectively precoated on each surface with organic coating and draw lubricant into one-piece can bodies ready for assembly into sanitary packs free of any requirement for washing, organic coating or repair of organic coating after fabrication and before such direct usage. Selective organic precoating includes embodying a blooming compound which is made available as draw lubricant responsive to heat and/or pressure of draw forming; also, surface application of a draw lubricant after curing of the organic coating. Combined lubricant on each surface is verified before start of fabricating. Draw-forming of tensile strength sheet metal is controlled over side wall height by clamping solely between planar clamping surfaces and by interruption of draw to establish a flange at the open end of cup-shaped work product. Surface area of the cavity entrance zone for each die is preselected along with curved surface transition zone on draw punch in relation to sheet metal substrate starting gage. Nesting of curvilinear clamping surfaces of the prior art is eliminated during redraw of work product. The curved transition zone of cup-shaped work product is reshaped prior to redraw.

Claims9

Dependent claims

Draw process system for fabricating flat-rolled sheet metal precoated with organic coating and draw lubricant into a one-piece can body, comprising

(A) means providing relatively light-gauge high tensile strength flat-rolled sheet metal can stock, predeterminedly coated on each surface with organic coating and draw lubricant, in the form of cut blanks,
(B) cupping means for drawing such a blank into a cup-shaped work product presenting:
a closed endwall,
a side wall which is symmetrically disposed with relation to a centrally-located axis for the work product,
such side wall defining an open end, spaced along the centrally-located axis of such work product, opposite to such closed endwall, and
flange metal extending peripherally outwardly at such open end so as to be disposed substantially perpendicularly transverse to such axis,
such cupping means for draw forming such cup-shaped work product including:
(i) a draw die defining an interior die cavity which is symmetrical with such centrally-located axis,
(ii) a die cavity entrance surface, which is curvilinear in a plane which includes such axis, selected to be as small as practicable while avoiding cutting of such sheet metal blank,
(iii) a planar clamping surface circumscribing such die cavity entrance surface and disposed to be substantially transversely perpendicular to such central axis,
(iv) a draw punch, for movement into such die cavity, having a curvilinear transition zone surface, between its endwall and side wall, which is as large as possible while avoiding buckling of sheet metal as such sheet metal is drawn into such die cavity, and
(v) clamping means presenting a planar clamping surface, circumscribing such draw punch side wall, for coacting with the planar clamping surface of such cupping die so as to place sheet metal peripherally exterior to such die cavity entrance under tension during work product fabrication so as to prevent any significant increase in sheet metal thickness of such work product side wall which would be detrimental to organic coating adhesion.

9 more elements

An integrated system for draw process fabrication of flat-rolled sheet metal into one-piece can bodies ready for direct use, as fabricated, in the assembly of two-piece cans, comprising

(A) means providing relatively light-gauge high tensile strength flat-rolled sheet metal predeterminedly coated on each surface with organic coating and draw lubricant, such flat-rolled sheet metal being provided in the form of cut blanks of predetermined cut edge dimensional and configurational characteristics,
(B) cupping means for drawing such a blank into a cup-shaped work product having a closed endwall, a side wall symmetrically disposed with relation to a centrally-located axis for such work product and defining an open end opposite to such closed endwall along such axis, and flange metal extending peripherally outwardly at such open end in substantially perpendicularly transverse relationship to such axis,
(C) redraw means for decreasing surface area of such work product endwall so as to add side wall height while maintaining flange metal about the open end of such side wall,
(D) means for profiling endwall sheet metal upon completion of redraw,
such draw-redraw operations being carried out with control of side wall metal so as to avoid any significant increase in sheet metal thickness along such side wall height which would be detrimental to organic coating adhesion;
and
(E) means of preparing such flange metal to provide for attachment of an end closure during assembly of a two-piece container, with
such system carrying out fabrication of such can body free of damage to side wall sheet metal and organic polymer coating so as to enable direct use of such can body for assembly of a two-piece container.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/421,777Filed 14 Apr 1995 · division
Priority: 1 Mar 1985
Granted: 6 May 1997
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

B21D 51/26
Characterised by the use of the objects: cans or tins; Closing same in a permanent manner
B21D 22/201
Deep-drawing: work-pieces; preparation of the work-pieces, e.g. lubricating, coating
B21D 22/22
Deep-drawing: with devices for holding the edge of the blanks
B21D 22/28
Deep-drawing: of cylindrical articles using consecutive dies

Family

Serial712,238Parent of this continuation-in-part · filed 1 Mar 1985
Serial831,624Parent of this continuation-in-part · filed 21 Feb 1986
Serial573,548Parent of this division · filed 27 Aug 1990
Serial866,661Parent of this division · filed 8 Apr 1992
US 5,409,130 AParent of this division
US 5,119,657 AParent of this division
US 5,626,049 AThis patent

From the US filing history. Foreign family members aren’t listed.