Improvements in the Manufacture of Seamless Compound Wire.
Year: 1891

page_text: Date of Application, 17th Feb., 1891-Accepted, 2nd May, 1891
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Seamless Compound Wire.
1 LEVI LYMAN BURDON 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:-
My present invention has relation to improvements in the manufacture of scamless
compound ingots, and wire produced therefrom; said invention, however, appertains
more particularly to seamless wire in which a core of base-metal, or other metal
having a relatively less value than the outer shell or plate, is united to a compara-
tively thin seamless shell of gold or other suitable metal; such wire being especially
adapted for the manufacture of watch-chains, finger-rings, bracelets, pins, &c..
In the operations employed in the reduction to wire of seamless compound ingots
it is very desirable that the metal be uniformly acted upon in order to preserve its
integrity throughout, especially at the union of the core and outer shell, because
otherwise the percentage of waste is so excessive as to preclude the employment
by jewellers of such imperfectly united scamless wire in lieu of the common seamed
plated wire.
Various attempts have been and are still being made to reduce seamless com-
pound ingots to a piece of continuous wire having a uniform size and quality
throughout, but such former attempts, so far as I am aware, have been attended
with failure or indifferent results, the product being irregular in size and not
sufficiently uniform in quality.
Heretofore the practice has been to attenuate or reduce plated ingots, particularly
such as are cylindrical in form, to a size adapted to be passed through a draw-
plate, by means of powerful squeezing rolls provided with a series of V-shaped
circumferential grooves gradually decreasing in size between which grooves the
ingot or rod is successively passed; sometimes the grooves are semi-circular in
cross-section, although still other forms of groove have been used, but in all of
them the action is to compress the metal most at two or more parts throughout the
length of the ingot while at the same time the metal not in actual contact with the
dies or grooves is distended or squeezed out laterally, thereby tending to separate
the atoms or fibres in that direction. Moreover, such method of reduction pro-
duces an unequal strain or tension upon the two metals composing the ingot and
frequently results in disuniting them in spots which latter after a few passes develope
into places having somewhat the appearance of abrasions, such portions when drawn
into wire being cut out as waste stock and possessing no commercial value.
such former methods of reduction the ingot or rod is turned slightly so as to present
a new surface to the rolls at each pass; I have found it to be practically impossible
to thus produce wire possessing the necessary homogeniety essential to plated wire
adapted to the use of jewellers. Sometimes power hammers, or trip-hammers,
have been used to reduce plated ingots But the result is substantially the same
as though they had been passed between driven rolls, as before stated. It should
be borne in mind that the metal is worked cold, although it is frequently annealed
during the reducing operation. I am aware that when a bar of iron or other
metal is thus acted upon, although it is usually worked hot, the result is practically
satisfactory, but when a compound ingot is substituted and worked cold the result
is quite different, for reasons before given.
In
I have discovered by extensive experimenting that in order to reduce a compound
ingot into wire which is well adapted for jewellers' purposes a, what may be
termed, swaging-process produces the best results. Usually in working metals

page_text: :
cold the effect seems to be to harden it, whereas by the swaging process about to
be described it appears to soften the metal, because after a considerable amount of
swaging the pieces of metal can then be bent more readily than metal reduced to
the same extent by other methods. The swaging mechanism which I have
employed in reducing compound ingots requires a series of dies in halves, the die-
cavities thereof gradually decreasing in size. The dies are mounted in the end of
a strong hollow shaft adapted to revolve rapidly the dies are fitted to move
slightly in a lateral direction. Each half being backed by a steel block or dog.
Arranged around the head of the machine are a number of normally stationary
cains or swage-blocks susceptible of adjustment, each having a spring which serves
to maintain the cams in position except for the instant when they are in contact
with the dogs. Now, upon introducing the end of the ingot between the revolving
dies the travelling dogs successively engage the free ends of the cams thereby at
each engagement slightly reducing the metal by compression and elongation, the
ingot meanwhile not being revolved. After the ingot has been acted upon by
one pair of dies, the latter are removed and the next smaller pair substituted, and
the ingot again acted upon, the operation being repeated until the desired reduction
is attained or until the size of the rod renders it susceptible of being passed
through a draw-plate. By this method of reduction or swaging all parts or portions
of the metal acted upon are subjected at the same time to the same or a uniform
degree of pressure, thereby producing a practically perfect homogeniety of the
metal. It will be observed that the action of the mechanism is to squeeze the dies.
together upon the metal from opposite sides at each successive engagement of the
dogs and cams, the rate of speed being several hundred compressions per minute.
By reason of such compressive action there exists no counter tendency to
stretch or tear the metal at some other part at the same time, as is common to the
usual hammering, rolling and drawing processes. Moreover, when rolls and hammers
are employed they further serve to harden the surace of the metal thereby
forming a "skin" which renders the rod or ingot very stiff, which is especially
undesirable in compound ingots. With the aid of compressing mechanism no such
skin is formed, the compression being a squeeze and not a blow, and as the dies are
nearly cylindrical it follows that nearly all the atoms or particles of the metal are
simultaneously acted upon from circumference to centre at a uniform pressure.
would state further that each individual squeeze does so little of the aggregate
work of reduction that there is no violent action upon the metal such as accom-
panies other cold-working methods. Swaging by this improved method not only
reduces the metal by squeezing it toward the centre from all directions while in
contact with the dies, but it also serves to hold the ingot centrally until it has
received the extreme degree of pressure from the dies. Still another advantage
derived from the cold swaging process is that as it acts to condense or compress the
entire mass equally there are. no fire-cracks or scams developed in the metal
during the several annealing; when, however, the metal is worked cold as in
rolling, hammering or drawing, fire-cracks frequently occur in annealing the metal ;
in some cases the percentage of waste is so great from this cause alone as to
preclude the manufacture of certain grades of compound ingots.
I
The object I have in view is to overcome the hereinbefore described defects or
disadvantages inherent in the former methods of producing seamless compound
wire, to that end my invention consists, essentially, in the following named steps,
viz. 1st forming a core or centre portion of suitable metal and a seamless
exterior shell or tube of metal having a greater relative value than the core
portion; next, suitably preparing the contiguous surfaces of the core and outer
shell and uniting them together, thereby producing the ingot; then, repeatedly
subjecting the ingot to a squeezing or swaging operation which acts to gradually
and uniformly reduce it from circumference to centre and at the same time
elongating it, and finally, subjecting the thus reduced ingot to drawing mechanism
which still further elongates it to seamless wire having the desired form and size
cross-sectionally, all as will be more fully hereinafter set forth and claimed.

page_text: In the appended two sheets of drawings illustrating my invention,
Figure 1 shows a side elevation of the centre or base-metal core portion;
Fig. 2 is a longitudinal sectional view of the outer seamless shell of metal having
a relatively greater value than the core;
Fig. 3 shows a thin piece of solder adapted to be wrapped around the core;
Fig. 4 shows the ingot, in partial section, before being soldered;
Fig. 5 shows the same, in reduced scale, mounted in a furnace and being subjected
to a flame to fuse the solder;
Fig. 6 is a side elevation of a swaging or squeezing machine adapted to uniformly
reduce the ingot from circumference to centre, thereby at the same time
elongating it;
Fig. 7 is an enlarged transverse sectional view taken through the head portion
of the machine, showing an end of the seamless ingot introduced between the dies
and in the act of being slightly reduced and correspondingly elongated;
Fig. 8 is an end view of the front end of the machine:
Fig. 9 is the same with the front plate or cover removed, the dies being
represented at the instant of their engagement with the reduced ingot or wire;
Fig. 10 is a similar view of the parts, the revolving dies, however, being discon-
nected from the dogs at the instant, as in successively passing from one cam to
another;
Fig. 11 is a plan view of the machine the head portion being in horizontal
section;
Fig. 12 represents in plan view a portion of a drawing-machine, that is a machine
provided with a draw plate in which is formed a series of holes gradually
diminishing in size through which the wire is successively passed, and
Fig. 13 is a front view of the draw-plate itself.
A manner of constructing the seamless ingot preparatory to being reduced to
compound seamless wire is as follows-
The core portion a of the ingot is usually composed of brass or base-metal; the
core may have any practical form and size, as for example it may be cylindrical or
tapering, and round or polygonal cross-sectionally.
The outer shell of the ingot consists of a seamless tube of fine metal or suitably
alloyed metal, its form transversely being substantially like that of the core
portion to which it is to be united. Sometimes the shell, itself is composed of
plated or compound stock, thereby making it of less relative value than the tube
first referred to. There are several ways of uniting the core and shell; one manner
of attaching them being to snugly fit the core into the shell, leaving a space or
chamber at the top in which loose solder is placed which latter melts and runs down
around and between the contiguous surfaces upon being subjected to a proper
temperature. Another way is to make the core a little smaller in diameter than
the bore of the tube and introduce between the adjacent surfaces a layer or sheet c
of thin solder, see Figs. 3 and 4, which fuses upon the proper application of a
suitable degree of heat. Still other ways of uniting the parts is to first cover or
coat the core with solder, or the inner surface or bore of the outer shell itself may
be lined with solder, the core being next introduced and the whole subjected to
heat, as before stated. Again the two parts a and may be fitted together and
then united by sweating, that is a union of one or more of the low-fusing metals
with which the core and shell are alloyed. It is obvious that the surfaces of the
metal in any case must first be suitably prepared or treated, as with borax in order
to facilitate the union of parts. The ingot A may be attached by an end a¹ to a
revolving gear-driven spindle a², the whole being inclosed within a hood or
furnace provided with an aperture through which the flame of a burner d is
directed onto the revolving ingot; as in Fig. 5.
After the outer shell is properly attached to the core, substantially as before
stated, the ingot is removed from the furnace and its end introduced cold between
a pair of dies D, Figs. 6 to 11, mounted in the front end of the hollow shaft H of
a swaging-machine B, which acts to slightly squeeze and reduce the metal of the

page_text: ingot from circumference to centre by reason of the rapid successive engagements
of the oppositely arranged pivotally mounted dogs d with the series of normally
stationary adjustably mounted spring-resisting cams or swage-blocks ; the con-
tiguous surfaces of the dogs and cams are preferably so curved that they will roll
into each other, the rolling action being similar to the epicycloidal curve frequently
used in gearing. As the dogs pass cach cam a straight spring in each (Fig. 7)
vibrates them rearwardly to the normal position against their respective stops,
see Figs. 9 and 10. The cams are backed by adjusting blocks into which the
cams are fitted to swing or vibrate somewhat; said blocks are adjusted by means
of strong blocks passing radially through the head of the machine. The dies
are prevented from moving endwise by a follower screwed into a flange h
secured to the front end of the hollow shaft or spindle H.
In reducing the compound ingot A. to seamless wire we adapted to be passed
through the holes of a draw-plate k, the ingot is first repeatedly passed through
the swaging machine, the dies D thereof being changed each time for others, the
several die-cavities s gradually decreasing in size until the desired reduction is
attained. The ingot or rod which is suitably annealed is held and prevented from
turning by the attendant during each pass through the dies; the result being an
attenuated rod practically true and homogeneous throughout its length, no seams,
blisters or abrasions being apparent. The action of the dies as hereinbefore
stated is to gradually squeeze the metal or atons composing it from circumference
to centre, as contra-distinguished from ingots reduced by the action of blows, as in
hammering, which latter not only hardens and crystallizes the metal but also acts
to distort it from a true shape; the latter being particularly true when the reduction
is effected by rolling processes.
After the swaging-machine has reduced the ingot to a rod or wire we having the
desired size it is then subjected to a drawing process; that is an end of the rod is
inserted through a hole of a draw-plate k mounted in a drawing-machine
(Figs. 12-13). Machines of this type are well-known; the jaws r attached to the
driving-chain 2 seize the end of the rod and pull it through the draw-plate, thereby
slightly reducing the rod transversely but at the same time elongating it; the
repeated passage of the wire through the gradually diminishing holes of a
suitable draw-plate finally reduces it to the desired form and size cross-sectionally,
the product being compound wire composed of a seamless exterior surface of gold,
or other fine metal, of uniform thickness united to an inner portion of low-grade
metal. I would state that it is obvious the ingot and wire should be properly
annealed at intervals during the process of reduction.
I make no specific claim herewith to the manner of producing seamless compound
ingots adapted to be reduced to seamless wire, as ingots of this class have been
previously patented, as for example, see my English Patents Nos. 6,081 of 1888;
6,082 of 1888, 18,842 of 1888, and 3,483 of 1890. Neither do I claim herewithi
the swaging mechanism represented and described for reducing the ingot to a wire
adapted to a draw-plate..
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 1
claim is:
1. The improvement substantially as hereinbefore described in the reduction by
cold working of compound ingots to rods or wire, the same consisting in repeatedly
subjecting the suitably prepared ingot to a squeezing or swaging operation which
acts to gradually reduce it from circumference to centre and at the same time
attenuating the ingot until the desired size is attained,
2. The improvement substantially as herein before described in the reduction by
cold working of compound ingots to rods or wire, the same consisting in repeatedly
subjecting the prepared ingot to a squeezing or swaging operation which acts to
gradually and uniformly reduce it from circumference to centre and at the same
time elongating it, and, next, successively passing the prepared rod thus reduced

page_text: through drawing mechanism which still further elongates it and gives to the wire
the desired form and size cross-sectionally.
3. The improvement hereinbefore described in the manufacture of seamless
compound wire, the same consisting in first producing a seamless exterior shell of
alloyed fine metal or even a seamless compound tube, next, introducing a suitable
metallic core into said shell, then uniting the core and shell, thereby forming the
ingot, next, repeatedly subjecting the suitably prepared ingot to a squeezing or
Swaging operation which acts to gradually and uniformly reduce it from circum-
ference to centre and at the same time elongating it, and finally, subjecting the
reduced ingot to drawing mechanism which acts to still further elongate it and
gives to the seamless wire thus produced the desired form and size cross-
sectionally.
PHILIP M. JUSTICE,
Associate Agent.