Year: 1888

page_text: I, LEVI LYMAN BURDON, of 584 Broad Street, Providence, State of Rhode Island,
United States of America, Manufacturer, 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:-
In the manufacture of compound or soldered seamless plated cylindrical ingots
adapted to be reduced into seamless plated wire it has been the practice heretofore
so far as I am aware, to turn the center portion, or base metal core, to a uniform
diameter throughout its length, the seamless tube of fine metal being in like manner
cylindrical and adapted to receive and be soldered to the core. Compound ingots
of this class are adapted to be subsequently reduced or drawn into wire and made
into chains, rings, and other articles of jewelry.
An objection to the cylindrical form of compound ingot is that during the process
of soldering the shell or tube to the core, the parts being in a vertical position
within the furnace, the shell while thus expanded by the heat frequently becomes
displaced and sometimes drops from the core. In some instances a support has
been placed beneath the parts to prevent the tube from thus falling off while being
subjected to the soldering process. This results in an unequal distribution of the
solder as it fuses and runs down and around the core from the fact that a slight
excess of heat or pressure on one side of the ingot will cause the shell to move
slightly in a lateral direction, thereby obviously producing an unequal thickness or
film of solder, as before stated. In fact it not unfrequently happens that owing to
this cause alone certain portions of the shell fail to become soldered to the core.
During the subsequent process of reducing the ingot these unsoldered places become
developed and are termed "blisters." Such imperfections materially increase the
percentage of waste stock, and consequently increases the cost of manufacture.
The object of my present invention is to overcome the objection or disadvantage
before stated. To this end I make the center portion or base-metal core of the
ingot tapering throughout its length-that is, larger at one end than at the other-
or having the form of a cone-frustrum. The seamless tube or shell has a corre-
sponding shape and is adapted to be placed over the core and then soldered thereto.

page_text: .
In the practice of uniting these parts I preferably provide a chamber or reservoir
at the upper end in which to place solder. Now upon suspending them vertically in
a suitably-heated furnace the solder melts and runs down and around the core in an
unbroken film. In case the shell expands faster than the core it simply drops a
short distance, or until it more closely engages a corresponding section thereof, the
conical form obviously serving to automatically center the shell-thereon. Another
advantage of the cone-shaped ingot is that it is more readily reduced while passing
through the "breaking-down" operation preparatory to being passed through the
"draw-plate," all as will be more fully hereinafter set forth and claimed.
In the accompanying sheet of drawings, Figure 1 represents a side elevation of the
cone-shaped ingot in reduced scale. Fig. 2 is a longitudinal section taken through
the center of the ingot. Fig. 3 is a perspective view of the center portion or base-
metal core. Fig. 4 is a similar view of the seamless fine-metal shell. Fig. 5 is a
central sectional view taken through the upper portion of the ingot, and showing
the shell extended to produce a chamber adapted to retain solder; and Fig. 6 is a
similar sectional view showing another way of constructing the solder-holding
chamber.
The following is a detailed description of my invention and including the manner
of its construction and general operation:
a (referring to the drawings) designates my improved compound ingot, the same
having the form of a cone-frustrum.
bindicates the core or center portion, made from any suitable base-metal or
compositions of metal, as common to compound ingots of this class. The surface of
the core is made true and conical, the upper portion, 61, being preferably contracted
and extended beyond the seamless shell, as clearly shown in Fig. 2, &c.
c designates the gold shell, the same having a conical form and being substantially
the same size internally as the plain portion of the core just described. The shell is
seamless and may be drawn into shape from a disk-form in a swaging-press provided
with suitable dies. Obviously the shell which forms the plating of the ingot may be
made of gold alloyed with suitable metals, or of silver, &c. In order to form a
reservoir or chamber, d, for holding solder, the upper or small end of the shell may
be extended, as at c, Fig. 5, or the same result may be effected by centering a
metallic funnel-shaped removable piece, c², upon the upper end of the shell, thereby
surrounding and inclosing the reduced portion of the core, as clearly represented
in Fig. 6.
The manner of uniting the shell and core is as follows: We will first assume
that the core band the seamless shell c have been shaped substantially as shown in
the drawings, the shell inclosing the core, and that a chamber or reservoir; d is
formed in which solder is placed. Now the whole is suspended vertically in a
suitably-heated furnace by means, say of a chain or rod whose lower end, m is
adapted to receive a hook, h, screwed into the small end of the core, as shown by.
dotted lines in Fig. 6. If necessary the rod m may be revolved slowly, thereby
causing the ingot to be uniformly heated. When a sufficient heat has been' attained,
the solder (previously placed in the chamber d) fuses and runs down in a film around
the surface of the core. During this heating process in case the shell expands to
a greater degree than the core the former will simply drop a short distance along the
I core, but at the same time it is automatically centered thereon, so that the relative
position of the parts always remain the same centrally. After the union of the
parts has been accomplished the ingot is withdrawn from the furnace, the walls of
the solder-holding chamber are removed, and the ingot is then ready to be passed
through the breaking-down rolls, &c. to reduce it, as usual.
In lieu of the operation just described I may first cover the surface of the conical
core b with a thin coating or film of solder and then place the core within' the seam-
less shell c, and submit the whole to the action of heat as before stated; the
reservoir d containing loose solder being used or not as desired. Or the same
result may be accomplished by wrapping a very thin sheet of solder (or other metal
employed to unite the core with the shell) of the proper size and form around the

page_text: cone-shaped core, and then insert the said core and solder within the seamless shell,
followed by fusing the solder in a suitable furnace. The finished ingot a in any case
having the form of a cone-frustruin and having its surface covered with a seamless
coating of fine metal united to the core.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to bo porformed, I declare that what I
claim is
1. As an improved article of manufacture, a compound ingot having the form of
a conc-frustrum, substantially as hereinbefore described.
2. The compound ingot hereinbefore described, consisting of the base-metal core
portion having one end somewhat larger in diameter than the other, and a seamless
shell portion having its interior substantially the same form and size as the core
portion.
3. The compound ingot hereinbefore described, the same consisting of a base-
metal core portion somewhat larger at one end than the other, and having a reduced
end, as ', adapted to first enter the reducing-rolls, and a seamless shell of fine metal
soldered to the core.
4. The compound ingot herein before described, the same consisting of a base-metal
core portion somewhat larger at one end than the other, and a seamless shell of fine
metal having its interior substantially the same form and size as the core portion,
and having a solder-retaining chamber or reservoir, as d, at the small end of the
ingot, substantially as set forth.
HUGHES, ELI & HUGHES,
76, Chancery Lane, London, W.Ć.,
Agents for the Applicant.