Compound ingots or Bars for the Use of Jewellers and others.
Year: 1888

page_text: Compound ingots or Bars
for the Use of Jewellers and others.
I, LEVI LYMAN BURDON, of Broad Street, Providence, Rhode Island in the
United States of America, Mechanic, do hereby declare the nature of the said
Invention, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
In an application for Patent of even date herewith, 1 have described and claimed
a compound ingot adapted to be rolled down or reduced, thereby producing a seamless
plated wire which is more especially employed in the manufacture of articles of
jewelry, such for example, as chains, pins, finger-rings, &c. .
The object of my present invention is to produce a uniformly soldered compound
ingot, the same being freer from "blisters" or unsoldered places which latter are
frequently developed in wire produced from ingots as usually nuade. To overcome
the defects just named is the aim of the present improvements; to this end pre-
ferably take a core of base metal of suitable dimensions and wrap a thin layer or
unbroken sheet of solder around it; I next place the core portion, thus covered, within
a seamless tube or shell of fine metal and snugly fitting the same, adding at one end
of the ingot if desired a chamber in which to place loose solder; the whole is then
submitted to the action of heat to fuse the solder, thereby producing a compound
ingot in which the core and seamless shell are perfectly united throughout by an
unbroken film of solder, as will be more fully hereinafter.described.
In the accompanying drawings, Figure, 1, represents a perspective view of the
complete ingot, having the seamless shell soldered to the interior core of base metal,
and ready to be rolled and drawn down into seamless filled wire. Fig. 2. is a longi-
tudinal sectional view thereof. Fig. 3. is a perspective view of a piece of solder of
uniform thickness, rolled into tube-form, adapted to be interposed between the core
and outer shell, the dotted lines indicate the sheet of solder before bending. Fig. 4.
is a similar view of a seamless tube of gold or other suitable metal. Fig. 5, is a
longitudinal sectional view of the ingot, wherein the shell extends somewhat above

page_text: the end of the solder tube to form a chamber. Fig. 6, is a similar view. The
extension, however, being produced by a removable annular cone-frustrum, and Fig. 7,
is a perspective view, in partial section, of a piece of wire as drawn down from the
ingot shown in the preceding figures.
A more detailed description of my improvement is as follows:-
B, indicates the ingot complete, ready to be reduced to wire by any known means,
as for example, suitably operated rolls and draw-plate. The upper end of the core
portion of the ingot extends beyond the end of the outer shell or plating, as shown
at c, Fig. 1, for the purpose of facilitating the entrance of the ingot between the
reducing rolls. Another advantage of said extension is that by this construction the
amount of waste stock is lessened, as compared with an ingot in which the gold
shell and core are of the same length.
Said
a, is a seamless shell of gold or other suitable plating metal, or alloy.
tube or shell may be formed from a blank by the use of plungers or in any other
manner. If desired, the lower end of the tube may be partially closed, as shown at, h,
Fig. 2.
b, Fig. 3, indicates a tube made of solder, although silver or other suitable metal
or compound may be used that will readily fuse and unite the core and outer shell, a.
As drawn, the tube, b, is represented as formed from the rectangular blank, -sec
dotted lines, the vertical edges meeting and forming the joint, b. It is evident,
however, that the solder tube may be drawn from a disk-like blank, substantially as
just stated with reference to the gold shell, a, or it may be made in the manner
employed in the production of lead piping, in which cases the said joint would be
omitted. I would state that the thickness of the walls of the tube, b, as drawn, is
considerably exaggerated. So also the walls of the outer tube are made somewhat
thicker than would be commonly used.
In Fig. 5, the upper portion of the gold shell is lengthened so as to extend-beyond
the end of the solder tube, b, thereby in connection with the conical portion, cl, of the
core, forming the annular chamber, c. This chamber serves as a small reservoir from
which may be supplied any slight additional solder that may be required due to the
expansion of the outer shell during the operation of soldering the core and shell: A
similar chamber is produced by the loose cone-shaped piece, adapted to engage
and rest upon the upper portion of the outer shell, as shown in Fig. 6. This piece, f,
may be made of inferior metal or material, thereby reducing the percentage of waste
stock, as compared with the arrangement shown in Fig. 5. In any event, I turn off,
or remove the said extension after soldering; as shown in Figs. 1, and, 2.
The core, c, of base metal, is turned off true to the desired size (or slightly less
than the interior diameter of the shell) and its surface suitably prepared or covered
with borax. The interior surface of the gold shell, a, is also, in like manner, prepared
or covered with borax, and the core then placed centrally therein, thereby forming an
annular space between the adjacent surfaces of the said parts. The shell or tube, b
of solder is then forcibly inserted into the annular space to the lower end of the core,
and the whole then subjected to the action of heat exceeding the fusing point of the
solder.
Practically I obtain the best result by vertically suspending the ingot and revolving,
or twisting it around while in the furnace, thereby uniformly heating its surface.
After the ingot is removed from the furnace it is found that the contiguous surfaces
of the shell and core are united throughout their length by a uniform thickness or
film of solder. Solder loosely placed in the chamber, ³, serves to ensure the filling of
the annular space therewith as the fusing progresses.
In lieu of forcing the tube of solder into position as before described, it may be
first inserted within the gold shell and the core then placed in position therein
and forced home under a light pressure, without departing from the spirit of the
invention.
.
After the ingot is withdrawn from the furnace or place of welding, the metal
surrounding the chamber, c³, being first removed, it is then adapted to be rolled
and drawn into seamless filled wire by the means usually employed in reducing

page_text: ingots of this class. The wire represented in Fig. 7, is seamless plated, the
relative proportion of the gold, a, to the base-metal core, c, being the same as in the
ingot.
22
By means of the use of a tube of solder the union of the parts forming the ingot
is assured, so that when reduced to wire no "blisters' appear on its surface,
thereby reducing the percentage of waste.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
:-
1. The improved method herein described of making compound ingots, the same
consisting, first, in preparing the surfaces of the base-metal core and the seamless
gold shell to unite with solder, next introducing the core within said shell thereby
forming an annular space between them; then, inserting a sleeve of solder into said
annular space, and finally, subjecting the whole to a high temperature which fuses
the solder, and unites the core and shell with a uniform thickness of the same.
2. The improved method of making compound ingots, which consists in inserting
a cylindrical base-metal core having a slightly reduced diameter within the outer or
gold shell, the surfaces thereof having been previously prepared to be united by
solder and having a chamber, as c², formed at the upper end; then, inserting a thin
sleeve of silver or other suitable solder between the core and shell and placing loose
solder in said chamber, and, finally, placing the whole within a suitably prepared
and heated furnace, thereby fusing the solder and uniting the core and outer shell
with a uniform thickness of the same, the ingot after withdrawal from the furnace
being adapted to be rolled and drawn down to produce seamless filled plated wire.
1000
DAY, DAVIES & HUNT,
321, High Holborn, London, W.C.,
Agents for the Applicant.