Improvements in and relating to Dies for use in Stamping or Punching Blooms and the like.
Year: 1893

page_text: Date of Application, 16th Jan., 1893-Accepted, 25th Feb., 1893
COME DIN DICIT ICATION.
Improvements in and relating to Dies for use in Stamping or
Punching Blooms and the like.
I, CARL GUSTAF LARSON, of Sandviken in the Kingdom of Sweden, Engineer,
do hereby declare the nature of this invention and in what manner the same is to
be performed, to be particularly described and ascertained, in and by the following
statement:-
My invention relates to an arrangement of matrices or stamping dies employed
in punching and similar machines in order to guide a heated piece of steel, iron or
other metal of a different transverse section than that of the hole of the matrice,
when the said piece is about to be punched. These matrices are particularly
designed for producing hollow blooms for rolling tubes, the blooms being in these
matrices provided with a central hole.
In the accompanying drawing,
Figure 1 shows how the matrices are applied and used.
Figure 2 represents one form of the improved matrices.
Figure 3 shows a piece of metal previous to punching, and
Figure 4 shows the same after the punching.
The matrice or die a is fitted into a recess in the anvil and is central with
respect to the axis of the punch c which may be secured to a steam-hammer, ram
or other suitable punching machine. The inside of the matrice may be provided
with longitudinal or transverse grooves or corrugations a¹ or the matrice may be
made of any suitable shape in cross section, so that the inside of the matrice has
not a uniform cylindrical surface. When the bloom d which is preferably round,
has been introduced into the matrice, it should fill the space, so that its exterior
may rest against the projecting parts in the hollow of the matrice, but leave inter-
spaces in other parts in the matrice. In this way the projecting parts a¹ will act
as guiding edges or surfaces for determining the position of the piece in the matrice.
The piece will therefore be in position directly under the punch, and the inter-
spaces allow the punch to penetrate through the piece in spite of the surrounding
matrice, as the material is forced into the interspaces, thus filling them more or less.
The uniform distribution of the latter around the piece also causes a uniform
distribution of the material of the said piece when being punched so that a finished
bloom as shown in Figure 4 is suitable for the rolling of a tube having walls of the
same thickness. The matrice may if desired be made in two or more parts.
I am aware that prior to this invention attempts have been made to punch holes
in pieces of polygonal cross section inserted in round or oval but not fluted dies,
but it has been found in practice that the piece fills up the die before the punching
is completed there being therefore no more room inside the die to allow the
material to expand in forming the necessary cross section of the hole. I therefore
do not claim a die arranged in such a way, inasmuch as the arrangements herein-
before described have been made in order to overcome the said inconvenience, so
that there will always be sufficient room inside the shell for the material to expand
outwards from its centre.
Having now particularly described and ascertained the nature of my said
invention, and in what manner, the same is to be performed, 1 declare that what
I claim is :-
1. For punching holes in heated pieces of steel, iron or other metal, placed in
stamping dies having a different cross section to that of the hole, the arrangement
in which the die, either in one piece or made in two or more parts, is fluted or
corrugated or otherwise formed on its inside so that the piece when being punched

page_text: will be guided by the inwardly projecting parts of the die, the spaces between them
affording sufficient room for the lateral expansion of the metal.
2. The modification of the arrangement above described in which the corrugations
of the stamping die are arranged transversely, so that the piece when being punched
will be guided by the inwardly projecting parts of the die the spaces between them a
affording sufficient room for the lateral expansion of the piece at different parts of
its length.
Tovu uay Ulauuary 1070.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.