Improvement in the Manufacture of Hollow Metal Goods.
Year: 1899

page_text: Date of Application, 7th June, 1899-Accepted, 8th July, 1899
COMPLETE SPECIFICATION.
Improvement in the Manufacture of Hollow Metal Goods.
I, JASPER WETTER, Patent Agent, of 37 & 39, Essex Street, Strand, in the
County of London, do hereby declare the nature of this invention, a communica-
tion from Emil Vogel, Engineer, of Erlenkamp 9, Hamburg, Germany, to be par-
ticularly described and ascertained in and by the following statement:―
This invention relates to the manufacture of hollow articles from flat plates
or discs of malleable metal.
A circular or angular plate of metal is heated, then placed concentri-,
cally upon a supporting ring or a plate having an opening smaller than
the diameter Ol' width of the said plate, subsequently the said metal
plate is pressed against the supporting ring or plate by means of a
mandrel having a much smaller diameter than the opening of the
supporting ring or plate, and is thereby caused to assume the shape of a cup
having in the centre the thickness of the original plate, while the bent edges are
thicker. By this treatment the metal of the plate is not stretched and weakened,
as in other processes, but is compressed and partly thickened, and there is no
danger of punching out the centre of the plate, if, as is the case in the present
process, the mandrel has a rounded extremity and does not touch the cup on the
sides during the whole operation, but allows free motion to the metal of the cup.
This operation may be repeated by placing the cup-shaped material upon a sup-
porting ring of smaller diameter than the first, and pressing it into the same by
means of the mandrel, so as to render the cup narrower and deeper.
Finally the cup-shaped intermediate product may be drawn out to the desired
width or calibre between mandrels and matrices in the usual manner.
"
In the accompanying drawings Fig. 1 is a section of a flat circular metal plate
serving as raw material and placed with its edges concentrically over the circular
opening of a supporting plate b. c represents the mandrel acting upon the
centre of the disc a.
Fig. 2 represents the disc a, after it has been pressed into the opening of the
supporting plate.
Fig. 3 represents the second stage of operation, the cup-shaped material a
having been drawn out between a die plate and a mandrel.
Fig. 4 represents the third stage of operation, the material a being pressed
through a die plate 62 with a narrower opening, and thereby drawn out further.
Fig. 5 is a plan of the flat plate a serving as raw material.
Having now particularly described and ascertained the nature of the sail
invention and in what manner the same is to be performed, we declare that what
we claim is:
The process for the manufacture of hollow metal goods, which consists in
pressing a flat metal plate when hot into or through an opening by means of a
mandrel, which during the whole operation touches the said plate with its
extremity only, and forms it into a cup in the manner illustrated by Fig. 2,

page_text: repeating the operation if necessary, and subsequently drawing out the interme-
diate product thus obtained between a mandrel and a die in the known manner,
substantially as described.
Dated this 7th day of June 1899.
FAIRFAX & WETTER;
Agents, 37 and 39, Essex Street, Strand, London.