Improvements in Compound Hollow Metal Ingots and Wire.
Year: 1890

page_text: Date of Application, 18th Nov., 1890-Accepted, 24th Jan., 1891
COMPLETE SPECIFICATION.
Improvements in Compound Hollow Metal Ingots and Wire.
I LEVI LYMAN BURDOU of No. 924 Broad Street Providence in the State of Rhode
Island United States of America Mechanic 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 production of seamless plated hollow wiro it frequently happens, especially
when the gold and base metal are not united, that in reducing the compound ingot to
wire the outer or gold surface will break or crack more or less as the reduction is con-
tinued, thereby increasing proportionately the amount of waste. Another source of waste
is due to the manner in which the hollow compound ingot is produced, that is the metal,
if plated stock is used, has first the form of a flat plate; from this compound plate a
disk is cut which by suitable tools is then transformed into a plated tube or ingot; the
scrap remaining after the disk is thus cut from the flat piece of stock hears
a considerable proportion of the whole, and in order to recover the precious metal such
waste must be subjected to refining processes, thereby obviously materially increasing
the cost of the product.
waste or
፡፡
32
The object I seek to attain is to greatly reduce the amount of waste stock in the
production of seamless compound hollow ingots and wire, to that end my invention
consists essentially in drawing or forming two tubes from separate plates or disks of
flat stock, composed of fine metal and base metal respectively, the outer or fine metal
tube being larger than the inner or base metal tube, the latter tube is next inserted
into the gold tube after which the two tubes are attached or united by solder, or they
may be united by "flushing," as the sweating process is sometimes termed. After the
tubes are united the compound seamless hollow ingot is next reduced to hollow wire by
any of the well known processes.
In the accompanying sheet of drawings illustrating my improvement
Figure 1 is a central longitudinal section view of one form of my improved hollow
ingot, preparatory to being reduced to seamless plated hollow wire ;
Figs. 2 and 3 are sectional views of one end of a seamless compound ingot having
modified forms;
Fig. 4 is a longitudinal sectional view of my improved compound seamless bollow
ingot having a closed end;
Fig. 5 is a longitudinal sectional view of the inner or base metal tube or shell ;
Fig. 6 is a similar view of the seamless tube or gold shell adapted to be attached or
united to the exterior of the base-metal tube;
Fig. 7 is an ingot similar to that shown in Fig. 4, but having a solder-holding
chamber at the top;
Fig. 8 is a sectional view of the hollow ingot having the lower end reinforced ;
Fig. 9 is a sectional view showing an outer seamless shell composed of plated stock
and an inner shell of baser metal united thereto;
Fig. 10 is a sectional view of my improved ingot having a taper form, and
Fig. 11 shows a piece of hollow wire reduced from my improved ingot.
In the drawings a indicates my improved seamless hollow compound ingot and the
hollow wire reduced therefrom. The ingot is composed of an outer seamless shell or
ube c of gold or other suitable metal attached wholly or in part to an inner shell or
ube d of baser metal.
с
The seamless outer shell c may be produced from a disk of gold or any other suitable
netal, the same being gradually transformed by suitable dies, &c., into a tubular shape.
f desired the bottom end of the tube need not be removed, thereby leaving it closed,
abstantially as shown in Fig. 6. A few small holes i may be drilled in said end to
cilitate the soldering operation. I would state that the outer seamless shell itself

page_text: may be made from a compound or plated disk, the gold c, which in this case can
be very thin, being on the outside and the thicker or plating metal c¹ on the inside, as
shown in Fig. 9..
The inner shell d is made of base metal, the manner of its production may be similar
to that just described relative to the gold shell, or it can be rolled up from a flat piece of
stock thereby producing a longitudinal seam which should be closed. The thickness
of the base-metal shell is usually much greater than that of the outer seamless gold
shell. After the two shells or tubes c, d, are made the smaller or base-metal tube or
core portion is inserted into the seamless fine metal tube, the two contiguous surfaces
having first been properly prepared and covered say with borax to promote the fusion
of the solder, and the whole subjected to a high degree of heat thereby soldering or
welding the parts together. The solder may be applied in various ways, as for example,
in the form of a very thin sheet inserted between the core portion and outer shell; or
the tubular core d may have its onter surface covered with thin solder before it is
inserted into the seamless gold shell, or the gold shell itself may be lined with thin
solder in lieu of covering the core d with solder. Instead of the foregoing manner of
applying the solder, a small chamber, as t, or even a larger one, may be formed at the
upper end of the ingot in which to place loose solder, or the chamber can be used as
an auxiliary reservoir from which the soldier is supplied. Sometimes it may be best
to unite the parts together by the sweating process, that is by a fusion of one or more
of the low-grade metals with which the outer and inner shells are alloyed. I make
no claim herewith to any particular way of attaching or uniting the seamless outer
shell with the inner shell d of baser metal.
C
While the parts are being soldered together by the action of heat, the presence of
solder through the small holes i formed in the base of the gold shell (Fig. 6)
indicates to the workman that the fusion of the solder is practically effected. After
the now united compound exteriorly seamless hollow ingot has been withdrawn from
the influence of said heat a hole h may be drilled in its lower end through which a
headed rod or bar m (shown by dotted lines in Fig. 8) is inserted; the rod serving as
a "leader" to which the reducing mechanism may be firmly secured. The hollow
ingot may be reinforced by soldering a piece of metal to the bottom end of the
chamber, the hole h extending through the whole, as shown in said Fig. 8.
In some cases the cap or closed end portion of the tubes (shown in Figs. 4 to 10
inclusive) may be left off and a plug or reducing end f inserted and soldered therein,
substantially as shown in Fig. 1, or the hollow ingot may be open at both ends, one
end being contracted, as shown by dotted lines Fig. 3, by swaging or other means
thereby adapting the ingot to enter the reducing mechanism and convert it into
hollow wire. I would add that the two shells of the hollow ingot a need not be
united throughout their length in order to produce hollow wire, as they may he
soldered or attached simply at the end which first enters the reducing mechanism,
although I prefer in most cases that the union of the two shells shall be continuous
throughout.
In Fig. 9 the hollow ingot is represented as consisting of a plated or compound
outer seamless shell composed of thin gold c united to base metal cand an inner tube d
of base metal united to the outer compound shell; this ingot is adapted to be reduced
to hollow wire, substantially as before described. By this latter arrangement the
proportion of gold used may be reduced, thereby correspondingly reducing the quality
of the product.
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
claim is :-
1. The improvement in the manufacture of compound seamless hollow ingots and
wire, consisting in forming a seamless tube of suitably composed metal and a smalle
tube of baser metal, then inserting the said smaller tube into the larger one, next
attaching or uniting the two tubes and finally drawing or reducing the ingot to seamles
hollow wire, substantially as hereinbefore described.

page_text: 2. An ingot for the manufacture of seamless compound hollow wire, consisting of a
compound tube having an end adapted to engage reducing appliances, said compound
tube being composed of an inner tube or shell of base metal and a seamless
exterior shell of finer metal attached or united thereto, substantially as hereinbefore
described.
3. A compound seamless hollow wire, consisting of a seamless exterior shell of
suitable metal and an inner tube or shell of baser metal united to the outer shell,
substantially as hereinbefore described.
4. The improved compound seamless hollow ingot hereinbefore described, con-
sisting of an exterior seamless shell or tube formed of sheet metal closed at one end,
and a hollow core or shell of metal closed at one end, secured to the said exterior shell
or tube.
Dated the 18th day of November 1890
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, Associate Agent.