Improvements in the Manufacture of Metallic Casts or Castings.
Year: 1887

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Metallic Casts or Castings.
We, CHARLES TAVERDON, and AUGUSTE LUDOVIC TAVERDON, Engineers, of 19, rue
Claude Bernard Paris, France do hereby declare the nature of this invention to be
as follows:
Our invention has for its object the cheap manufacture of castings, which do not
require subsequent finishing by means of the file, chisel, shaping, turning, or other
analogous tools. For this purpose we proceed as follows.
Accurate moulds are made from any suitable metal or alloy, or combination of
metals, either:
a, by electro plating, or
b, by the combination of electro plating with ordinary casting, a thin layer following
exactly the desired contour being first formed by electro deposition, and subsequently
lined or backed with metal by ordinary casting in order to render the mould capable
of resisting strong internal pressure; or
c, by the compression of plastic materials adapting themselves to a standard form.
The metal from which the said casts or castings are to be made is introduced into
the moulds, obtained as described, either by casting in the ordinary way, with or
without the application of pressure ;-or by electro deposition; or by a combination
of the two processes.
In some cases, finished or unfinished pieces of the same, or of a different metal,
either hardened or not, may be introduced into the mould before it is filled. Hollow
castings, without a core, may be obtained by imparting to the mould a rotary or
oscillating motion; the liquid metal being introduced into the mould through the
hollow journal or trunnion; and spread over the surface of the mould by centrifugal
force. In some cases, also, the moulds or matrices are entirely or partly made of
flexible material such as india rubber; which allows castings having laterally
projecting parts to be removed after hardening without the previous destruction of
the mould.

page_text: As mentioned above, any fusible metal, or metal capable of electro deposition, may
be employed for the manufacture of castings or casts by our method; but we prefer
in most cases, to employ an alloy of copper, tin, and antimony.
Dated this 12th day of December 1887.
FAIRFAX & WETTER,
433, Strand, London,
Agents for the Applicants.
NAME INIM DIBLE ICATION.
Improvements in the Manufacture of Metallic Casts or Castings.
We, CHARLES TAVERDON and AUGUSTE LUDOVIC TAVERDON, Engineers, of 37, Rue
Philippe-le-Bon, Bruxelles, Belgium, do hereby declare the nature of our invention
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
:
In mechanical arts, the unaided process of casting (that is to say, without subsequent
finishing work) has only been employed for the production of a certain class of objects,
viz. those which are not required to possess either perfect accuracy, or essentially
different qualities in different parts, for instance, great hardness at certain points, and
softness at others, or a very malleable surface, and a very rigid core, etc.
The present invention, however, has for its object to obtain, as casts or castings,
all possible parts of mechanism without requiring any subsequent corrections or
finishing operations, such as cutting with the chisel, shaping, filing, etc.
This process consists in introducing into moulds or matrices, which combine the
necessary qualities, metals or metallic alloys in a liquid state, (whether fused by heat,
or held in solution), and causing this metal to fill exactly all the details of the mould,
by means of artificial pressure, either static or dynamic, the whole eventually com-
bined with the previous introduction, into the said moulds, of pieces having special
proprieties of hardness, rigidity, resistance to wear and tear and others.
This process generally comprises a series of different operations, which may be
classified as follows:-
1. Preparation of the moulds.
2. Preparation of the metallic alloy possessing the requisite properties.
3. Casting, by introducing the fused metal, or producing a cast by electro-doposi-
tion, or by both methods combined, and with or without artificial pressure, eventually
with the previous introduction of finished pieces.
4. Taking the casting out of the moulds.
And it moreover comprises, for certain applications, certain special peculiarities
which we will describe hereafter.

page_text: 1. PREPARING THE MOULDS.
The moulds or matrices may be made from various metals, such as cast iron, bronze,
cast steel, or in certain cases from plaster, fossil meal, or other plastic materials which
have the property of setting and hardening in the mould.
In the first case, that is to say when metals are employed, the process of preparing
the moulds constitutes a special application of our new process of manufacture, and
consists in the following:
After having made a first standard piece or pattern by the ordinary methods, and
with the greatest possible accuracy, this piece is prepared for electro-plating, by
applying the usual means for making it a conductor, if the said standard piece is not
metallic, and for preventing the adhesion of the galvano-plastic coating. Subsequently
the piece is coated with a more or less thick and non-adhesive layer of iron, copper,
nickel or platinum, by the ordinary methods of electro-plating.
Having thus obtained a thin metallic film which forms an absolutely exact mould,
the standard piece is removed and the mould backed with metal by the ordinary
process of casting, that is to say, the thin mould produced as described is coated
externally with cast metal, so as to obtain a strong inould capable of resisting the
pressures, to which it is afterwards exposed.
In the second case, that is to say, for obtaining matrices of plaster, fossil meal, etc.,
it is sufficient to compress, for instance, by means of a hydraulic press, the plastic
material surrounding the standard piece.
Besides the matrices constructed in the manner just described, we employ for
certain shapes of castings, moulds in which certain parts consist of india-rubber. If
metallic alloys are used which have a low melting point, the fused metal will not
destroy the portions made of India-rubber, a fact which has been proved by experience,
and is probably due to the rapid absorption of heat by the metallic walls which con-
stitute the principal part of the mould. This method facilitates the removal of castings
having laterally projecting parts, (viz.: those which are usually made with piece
moulds), without destruction of the moulds, in consequence of the extensibility of

page_text: obtained an external film having exactly the external shape of the piece to be produced,
it is sufficient, to fill the inside of the piece with molten metal or metallic alloy.
In this manner, we obtain pieces having an exactly shaped outer surface and a rough
core, which may be rigid or comparatively flexible, hard or malleable, according to
requirements.
d. Casting with the aid of static pressure.
To ensure, that the fused material shall take the exact shape of the mould, we
apply generally a gas or a liquid under pressure, that is to say, by putting the mould
filled with molten metal into communication with a chamber which contains a fluid at
the required pressure.
e. Casting with the aid of dynamic pressure.
We have also produced the required pressure by dynamic means, that is to say, by
communicating to the matrix, while the molten metal enters the same, a rotary or
oscillating motion or a compound motion, having the effect of distributing the molten
metal over the surface of the mould.
By this process, we obtain, without using a core, hollow castings, the external
surface of which is a faithful representation of the mould, and the hollow may
afterwards be filled by metals melted and cast in the ordinary way. To permit the
casting during the rotary motion of the mould, the latter need only be mounted on
hollow trunnions or journals, which will serve as inlets for the molten metal.
f. Introducing finished pieces into the mould.
In many applications it is useful to introduce into the matrix, before the casting,
certain organs which may or may not be hardened, and may or may not be dressed,
fashioned or finished (tapped, drilled, shaped, etc.) so as to obtain, after the removal of
the moulds, a mixed piece formed by the union of rough castings with parts previously
finished by other mechanical processes. For this purpose, it is only necessary to
provide in the matrices suitable blanks or recesses, into which the said pieces are
placed before filling the mould, either by ordinary casting, or by electro-deposition, or
or both methods combined, as described above.
The removal of the finished casting from the mould, offers nothing peculiar, except
in the case of pieces provided with laterally projecting parts (that is, castings which
are usually made by means of piece moulds).
As we have stated in the description of the moulds, those which we employ in
making castings usually made with piece moulds, have parts made of india-rubber,
these rubber parts corresponding to those portions of the finished casting, which could
not have been taken out of a rigid mould. As a rule, these rubber portions are
clamped or held between the metallic portions of the matrices. In taking out the
casting, we therefore commence by removing the metallic parts of the matrix,
subsequently, when the casting is uncovered, except at certain points which are still
covered with the parts made of india-rubber, the latter are easily extricated owing to
their extensibility.
Their elasticity restores them afterwards to their original shape, and they may be
used again by replacing them between the metallic parts of the mould, where they are
again held fast.
Having thus described in a general manner the operations, the combination of
which constitutes our new process for the manufacture of metallic casts or castings,
the applications of which are extremely numerous, we do not consider it necessary to
enumerate the said applications.
1

page_text: 1. The production of accurate moulds in any metal, or combination of metals, either
mixed together, or placed one over the other.
a. By electro-deposition.
b. By the combination of electro-deposition for producing a thin accurate mould,
with a strong metallic lining obtained by ordinary casting, and serving to
render the mould capable of resisting strong internal pressures.
c. By the compression of plastic materials adapted to set and harden in the
mould.
2. The method of producing finished pieces, by introducing the metal into the
moulds mentioned under (1), this introduction taking place by the ordinary process
of casting, with or without the aid of pressure, or by electro-deposition, or by a
combination of these two processes.
3. In combination with the method described under (2), the previous introduction,
into the moulds, of finished or unfinished pieces, of the same or of a different metal,
either hardened or not.
4. The production of hollow castings, without a core, by casting in moulds to which
rotary or oscillating motion is imparted, the metal being introduced into the mould
through a hollow journal or trunnion and distributed over the surface by centrifugal
force.
5. The application of moulds or matrices wholly or partly flexible, of india-rubber
or other suitable material, and allowing the easy removal of the castings provided
with lateral projections.
B. The application of the process described above, for the manufacture of metallic
or semi-metallic articles, organs or linings, being products which have hitherto been
obtained by other methods.