Metal can bodies

Details Metal can bodies Metal can bodies

1982-12-07

1984-11-20

Gilden, Leon

Metal deforming

By use of closed-die and coacting work-forcer

Cup or shell drawing

72470, B21D 2200

Patent

active

044831714

DESCRIPTION:

BRIEF SUMMARY
This invention relates to metal can bodies in the form of a cup, i.e. bodies comprising a generally cylindrical wall (of circular or other transverse cross-section) and an integral base at only one end of said wall, and to a method and apparatus for manufacturing such can bodies.
Such can bodies having said wall formed with a small taper longitudinally (i.e. said wall bounds a frustum of a cone) are known, and have substantial advantages so far as storage and transport are concerned, since such tapered can bodies can be nested together, each can body then being largely enclosed within the next can body.
However, the successful manufacture of such tapered can bodies has been difficult to achieve. Many tool systems for the drawing of tapered can bodies have been proposed and tried. Most such systems have combined taper drawing with straight redrawing in the same tool, and some of them have employed expanding mandrels, or expanding dies. In most cases, however taper drawing has resulted in badly wrinkled and/or creased tapered walls. To some extent an expanding mandrel made from an elastic material has prevented wrinkled formation, but only at the expense of rather low production rates, and short tool life.
Use of the word "taper" or any derivative thereof as a noun, adjective or verb hereinafter in respect of a can body, workpiece or tool element, means, to the extent allowed by the context, that the cross-sectional area decreases (while maintaining its symmetry with respect to a central axis) over a major part of the length of the tool element, or of the can body or workpiece from the open end thereof, as the case may be.
The present invention seeks to provide a method and tooling system for the taper redrawing, in a separate operation, of a cylindrical walled can body (for forming a two-piece can) made from low gauge material; and, moreover, to provide such a method and tool system which will cover all can proportions, including those cases where the height exceeds the diameter, and where the taper angle is kept to a minimum (i.e. below 3.degree.) but is sufficient to ensure the desired nesting density of can bodies, i.e. in which the longitudinal separation of the respective can bodies is of the order of 10 mm.
According to a first aspect of the present invention a method of forming a tapered-wall metal can body by drawing includes the steps of: cylindrical wall, an integral base at one end of said wall, and a trimmed free rim exposed at the opposite, open end of said wall, said rim being generally normal to said wall; "tapered die") by means of a punch engaged inside the blank with only the base of said blank, so as to bring the said wall progressively into greater contact with a tapered internal working surface of the die; well as transverse restraint, to the exposed free rim of the said wall whereby to urge the blank squarely into the tapered die, and maintaining at least that pressure, and restraint, as the blank is advanced progressively further into said tapered die; and said punch and simultaneous application of said longitudinal pressure, and transverse restraint, to said rim, until the said wall lies uniformly against said working surface of said die throughout a desired longitudinal length of said wall.
By exercising a proper control over the ratio of the respective pressures applied to the can body blank at its base, by said punch, and at its exposed free rim, it has been found possible to produce can bodies which are substantially free from all wrinkling and creasing.
Preferably, said can body blank has a said integral base which merges gradually into said cylindrical wall, preferably by means of a short tapered section.
Said tapered internal working surface of said die may in some cases by constituted by a series of successive sections of which the respective cross-sectional areas transverse to the direction of advancement of said blank in said die decrease progressively from one said section to the next in the direction of advancement of said blank into said die.
Each said section of said in

REFERENCES:
patent: 814054 (1906-03-01), Lamb
patent: 3820369 (1974-06-01), Tominaga et al.
patent: 4157693 (1979-06-01), Openchowski

Affiliated with

Also associated with

Rating

Metal can bodies does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Metal can bodies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Metal can bodies will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2183814