Method and apparatus for manufacture of a vessel
OwnerKarl Fischerinventor
Life of this patent
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Abstract
Method and manufacture for the manufacture of a cooking vessel with a flat, thick-walled bottom and a substantially thinner casing surface, a cup-shaped blank is shaped in the casing area by a rolling process on a substantially cylindrical, rotary mould part. The rolling tool comprises a rigid outer ring and numerous freely rotatable balls revolving in a groove. The area close to the bottom of the mould part is tapered, so that a cavity is formed into which the material can be shaped in the area close to the bottom.
Claims16
A method for manufacturing a stainless steel cooking vessel from a cup-shaped blank of stainless steel, the blank having a wall and a bottom, the bottom having a substantially planar bottom surface, comprising the steps of:
- positioning the cup-shaped blank on a substantially cylindrical mandrel, the mandrel having an outer diameter corresponding to the finished inner diameter of the wall of the cooking vessel, except for a tapered end portion having a smaller diameter, the tapered portion and the blank defining an annular recess therebetween;
- disposing an annular arrangement of at least five individually rotatable balls co-axially with the mandrel, the innermost points of the at least five balls defining the finished outer diameter of the wall of the cooking vessel;
- and,
- effecting a one-step rolling process, from the bottom of the cup-shaped blank upwardly, by axially displacing at least one of the mandrel and the annular arrangement of rotatable balls toward one another and rotating at least one of the mandrel and the annular arrangement of rotatable balls relative to the other, whereby the lower portion of the wall defining the annular recess is pressed inwardly and left relatively thick, the upper portion of the wall defining the annular recess is pressed inwardly and progressively made thinner and the remainder of the wall is made substantially and uniformly thinner, all without disrupting the planar bottom surface, so that no further machining operations are required to finish the outer surfaces of the bottom and wall.
A method according to claim 8, further comprising the step of simultaneously moving the balls in the processing direction, thereby providing a compound inclined movement away from the vessel.
An apparatus for manufacturing a stainless steel cooking vessel having a flat bottom and a substantially cylindrical wall, the bottom and the wall being formed integrally from a cup-shaped stainless steel blank, the blank having a substantially planar bottom surface, the apparatus comprising:
- a substantially cylindrical mandrel, the mandrel having an outer diameter corresponding to the finished inner diameter of the wall of the cooking vessel, except for a tapered end portion having a smaller diameter, the tapered portion and the blank defining an annular recess therebetween when the blank is placed on the mandrel;
- a rolling tool having a rigid outer ring, a circulating groove in the ring and at least five individually rotatable balls disposed in the circulating groove, the rotatable balls defining the finished outer diameter of the vessel;
- and,
- means for axially displacing at least one of the mandrel and the rolling tool toward one another and for rotating at least one of the mandrel and the rolling tool relative to the other, whereby a one-step rolling process is effected from the bottom of the cup-shaped blank upwardly, the lower portion of the wall defining the annular recess being pressed inwardly and left relatively thick, the upper portion of the wall defining the annular recess being pressed inwardly and progressively made thinner and the remainder of the wall being made substantially and uniformly thinner, all without disrupting the planar of the bottom surface, so that no further machining operations are required to finish the outer surfaces of the bottom and wall.
Dependencies are inferred from the claim text.