IMPROVEMENTS IN HARDENING STEEL PLATES, AND IN APPARATUS THEREFOR, AND IN SAFES CONSTRUCTED WITH SUCH PLATES
Year: 1876

page_text: LETTERS PATENT to Gerard Wenzeslaus von Nawrocki, of the Firm of J. Brandt
and G. W. v. Nawrocki, of Berlin, Prussia, Engineers and Patent Agents, for
the Invention of "IMPROVEMENTS IN HARDENING STEEL PLATES, AND IN
APPARATUS THEREFOR, AND IN SAFES CONSTRUCTED WITH SUCH PLATES."
A communication from Robert Neumann, residing at Koenigsberg, Prussia,
Safe Manufacturer.
Sealed the 14th October 1876, and dated the 29th June 1876.
PROVISIONAL SPECIFICATION left by the said Gerard Wenzeslaus von
Nawrocki at the Office of the Commissioners of Patents on the 29th June
1876.
GERARD WENZESLAUS VON NAWROCKI, of the Firm of J. Brandt and G. W. v.
Nawrocki, of Berlin, Prussia, Engineers and Patent Agents. "IMPROVEMENTS IN
HARDENING STEEL PLATES, AND IN APPARATUS THEREFOR, AND IN SAFES CON-
STRUCTED WITH SUCH PLATES." A communication from Robert Neumann, residing
at Koenigsberg, Prussia, Safe Manufacturer.
In the hardening of large steel plates it has heretofore frequently happened that
the plates in cooling became warped, and that they cracked more or less, sometimes
right through. Now, according to this Invention, steel plates of any required size
are hardened in striped or other patterns of varying hardness, all as herein-after
described.
The plate is heated to an even red heat in a furnace, and is placed between two
truly planed cast-iron plates, which are formed with grooves across of about say
3th of an inch depth and width, and perforated with many small holes. The upper
cast-iron plate has a projecting flange all round on its upper face, thus forming a box,
which can be raised and lowered as required by means of a lever and rods, or other
suitable apparatus. The lower cast-iron plate rests in a recess in the sides of a box or
trough, which rests on a substantial frame or table of wood or other suitable material.
A water pipo terminates with its outlet opening in the centre of the upper box-

page_text: shaped cast-iron plate; another water pipe terminates with its outlet opening in the
centre of the lower iron box or trough; these two pipes are supplied from a raised
tank, water being admitted simultaneously to them by means of two cocks, which
are coupled or connected. The two plates are forced together by means of hooks
riveted to a movable rail or bar, and brought in contact with corresponding pegs on
the upper plate. There is a cock for letting off the water.
The mode of hardening is as follows:-The red hot steel plate is placed on the
lower cast-iron plate, the upper one being suitably raised; the latter is then let
down; the aforesaid hooks are hooked in with the pegs. The water cocks are then
opened, and the water flows in simultaneously from above and below in the centre
of the plate and cools it. The places where the grooves are become hard as glass,
because of the greater flow of cold water thereto, and the other parts or stripes,
which are squeezed hard between the two plates, are cooled more slowly, and there-
fore become softer. The water being let in in the centre prevents the cracking of
the steel plate as the latter gets time to contract evenly. The warping is prevented
by the steel plate being held firmly between the two cast-iron plates.
When hardening plates welded up of steel and wrought-iron the lower cast-iron
plate is made without grooves, the plate is placed thereon with the iron side down-
wards, and water is only admitted to middle of the upper cast-iron plate by the
pipe, the other cock being left shut.
Instead of straight stripes of steel of different hardness any other striped or other
patterns may be applied, the grooves being made to any required pattern.
Plates made by the aforesaid process and apparatus are applied to safes. I will
now deseribe its application to a peculiar construction of safe.
This safe consists mainly of an outer iron box of ordinary construction. This
box is strongly rivetted to steel plates, made according to the aforesaid process, and
to iron plates inside of the steel plates. Inside of these comes a space for ashes or
other fire-resisting material, and then an iron box; this latter is covered with over-
lapping circular spring hardened steel discs or scales, turning each on a central pin,
and of, say, about 3 inches diameter, the outer or overlapping discs by preference
all but touch each other, and no space is left uncovered by the scales, so that the
drill will break if attempts be made to bore through this scale surface. Inside of
this again follows an air space for additional security against fire, and inside of this
again a box made of steel plates made according to the aforesaid process.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Gerard Wenzeslaus von Nawrocki in the Great Seal Patent Office
on the 29th December 1876.
GERARD WENZESLAUS VON NAWROCKI, of the Firm of J. Brandt and G. W. v.
Nawrocki, of Berlin, Prussia, Engineers and Patent Agents. "IMPROVEMENTS IN
HARDENING STEEL PLATES, AND IN APPARATUS THEREFOR, AND IN SAFES CON-
STRUCTED WITH SUCH PLATES." A communication from Robert Neumann, residing
at Koenigsberg, Prussia, Safe Manufacturer.
In the hardening of large steel plates it has heretofore frequently happened that
the plates in cooling became warped, and that they cracked more or less, sometimes
right through. Now, according to this Invention, steel plates of any required size
are hardened in striped or other patterns of varying hardness, all as herein-after
described.
And in order that this Invention may be more fully understood I will now
describe the same with reference to the accompanying Drawings.
Figure 1, Sheet I., is a side view; Figure 2, a vertical longitudinal section; and

page_text: Figure 3, a plan of the lower portion of an apparatus for hardening steel plates,
according to this Invention; Figure 4 is a full size section, and Figure 5 a plan of
a detail.
The plate is heated to an even rod heat in a furnace, and is placed between
two truly planed cast-iron plates a, a¹, which are formed with grooves across of
about, say th of an inch depth and width, and perforated with many small
holes i. The upper cast-iron plate a has a projecting flange all round on its upper
face, thus forming a box, which can be raised and lowered as required by means of
a lever A and rods v, or other suitable apparatus. The lower cast-iron plate a¹
rests in a recess in the sides of a box or trough b, which rests on a substantial frame
or table B, of wood or other suitable material. A water pipe c terminates with its
outlet opening in the centre of the upper box-shaped cast-iron plate a; another
water pipe c¹ terminates with its outlet opening in the centre of the lower iron box
or trough b; these two pipes are supplied from a raised tank O, water being
admitted simultaneously to them by means of two cocks, which are coupled or con-
nected. The two plates a, a, are forced together by means of hooks m, riveted to
a movable rail or bar o, and brought in contact with corresponding pegs i on the
upper plate a. There is a cock u for letting off the water.
The mode of hardening is as follows:-The red hot steel plate is placed on the
lower cast-iron plate a¹, the upper one a being suitably raised; the latter is then let
down, the aforesaid hooks m are hooked in with the pegs. The water cocks d, d¹,
are then opened, and the water flows in simultaneously from above and below in
the centre of the plate and cools it. The places where the grooves are become hard
as glass, because of the greater flow of cold water thereto, and the other parts or
stripes, which are squeezed hard between the two plates a and a¹ are cooled more
slowly, and therefore become softer. The water being let in in the centre prevents
the cracking of the steel plate as the latter gets time to contract evenly.
warping is prevented by the steel plate being held firmly between the two cast-iron
plates.
The
When hardening plates welded up of steel and wrought iron the lower cast-iron
plate a¹ is made without grooves, the plate is placed thereon with the iron side
downwards, and water is only admitted to the middle of the upper cast-iron plate a
by the pipe c, the other cock d¹ being left shut.
Instead of straight stripes of steel of different hardness any other striped or other
patterns may be applied, the grooves being made to any required pattern.
Plates made by the aforesaid process and apparatus are applied to safes. I will
now describe its application to a peculiar construction of safe.
Figure 1, Sheet II., is a vertical section at line A, B, Figure 4; Figure 2, a front
elevation, the door being partly broken off; Figure 3 is side elevation, part of the
side being left out; Figure 4, a plan section, at line C, D, Figure 1; and Figure 5 is
a full-size section, showing a peculiar construction of scale wall. This safe consists
mainly of an outer iron box a of ordinary construction. This box is strongly
riveted to the steel plates b, made according to the aforesaid process, and to the
iron plates c inside of the steel plates. Inside of these comes a space d for ashes
or other fire-resisting material, and then an iron box e; this latter is covered with
overlapping circular spring hardened steel discs or scales f, turning each on a central
pin, and of, say, about inches diameter, the outer or overlapping discs by prefer-
ence all but touch each other, and no space is left uncovered by the scales, so that
the drill will break if attempts be made to bore through this scale surface. Inside
of this again follows an air space h for additional security against fire, and
inside of this again a box g made of steel plates, made according to the aforesaid
process.
And having thus fully described this Invention, I declare that I claim,―
First. The process and apparatus for variously hardening massive steel plates or
plates welded up of steel and iron in striped or any other patterns, as set forth.
Second. The application of plates of steel or of steel and iron, variously

page_text: hardened, as described to safes in general and to the construction of safe here
described in particular.
-
In witness whereof, I, the said Gerard Wenzeslaus von Nawrocki, have here-
unto set my hand and seal, this Twenty-second day of December, in the year
of our Lord One thousand eight hundred and seventy-six.
G. W. v. NAWROCKI. (L.S.)