Improvements in and relating to Apparatus for use in Electric Welding, Forging, and other Metal Working Operations.
Year: 1890

page_text: Date of Application, 18th Nov., 1890–Accepted, 20th Dec., 1890
COMPLETE SPECIFICATION.
[Communicated from abroad by HERMANN LEMP, of 19, Alleu Avenue, Lynn,
Massachusetts, United States of America, Electrical Engineer.]
Improvements in and relating to Apparatus for use in Electric
Welding, Forging, and other Metal Working Operations.
1, HENRY HARRIS LAKE of the firm of Hasoltine, Lake & Co, Patent Agents,
45, Southampton Buildings, in the County of Middlesex, 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 :-
This invention relates generally to electric metal working apparatus of the class
in which electric currents of large volume but low electro inotive force are passed
through the work for the purpose of heating the same and reducing it to the
desired condition of plasticity, as in electric welding, forging soldering, riveting and
other operations.
The first part of the invention consists of certain improvements in the construction
of that class of electric metal working apparatus in which the current for beating the
work is derived from the secondary of a transformer or converter the primary of
which consists of a number of turns of electric conductor traversed by alternating or
other currents while the secondary which supplies the current to the work directly or
through the intervention of clamps or holders for the work is composed of a bar or bars
of copper made in a single piece or a number of pieces fastened together.
In metal working operations wherein a current of large volume but of comparatively
sinal pressure or electro motive force is employed it is necessary to increase the
volume of current with increase in the conductivity or cross sectional area of the
metal to be heated, and in practice it has been found that the pressure or electro
motive force is in effect a practically constant factor which does not have to vary
with different sizes of work. It is in fact desirable to have a practically uniform
pressure in different sizes of apparatus because of the uniformity in construction
which it permits so far as concerns the construction of the core of the transformers.
In providing for the necessary increase of volume for large work or work of low
conductivity, the attempt has been made prior to this invention to get the requisite
quantity or volume by increasing the cross section of the secondary bar used but this
has been found impracticable and inconvenient owing to the large weight and size
of the secondary bars which it necessitates thus making the apparatus heavy and -
unwieldy to use and not compact Such variation in the cross sectional area of the
secondary bar or conductor besides introducing a variation into the size of the
conductor itself of necessity produces a variation in the length of the iron core for
the apparatus which it is obviously desirable should be of uniform length for
convenience of manufacture and for other reasons.
The present invention consists essentially in constructing the apparatus with a
plurality of transformer secondaries arranged in parallel or in intersecting planes and
made to supply the current to the work or the work holding devices in parallel or
multiple arc circuits. Preferably the several secondary bars or conductors from which
the apparatus is constructed have different or independent iron cores. The secondary
bars or conductors may however have the same iron core or a core which is common
to the secondaries in part only.
Another part of the invention consists in a means whereby the uniform heating at
different parts of the work may be obtained. This part of the invention is especially
applicable to cases where the areas of material to be heated at once are large or
extended or subdivided and which, owing to the want of uniformity of contact or of
conducting capacity at different parts of the work, are liable to heat unevenly. This
part of the invention consists essentially in supplying different parts of the same work

page_text: from different sources of energy and regulating the different sources as occasion may
require to determine the supply of current from them. This part of the invention is
preferably carried out by applying to the same work a number of transformer
secondaries which supply current to different parts thereof in multiple or parallel are
and by regulating the current flowing in the different primary circuits or coils which
inductively set up the currents in said secondary.
Another part of the invention consists in the special construction of transformer
which is particularly adapted for use in the process of welding two separate joints
simultaneously in parallel as in a chain link. In this class of work it is difficult to
make both sides heat at the same rate and reach the welding point at the same time.
The construction of the transformer comprising this part of the invention permits the
current to be readily controlled at the two joints and secures the practical advantage
of two separate transformers having a separate iron core and primary by the employ-
ment of a single core having a magnetic bridge piece passing across from one side
to the other thereof and adapted to form a path for the magnetic energy of the core
when the current of one of the primaries is varied as hereinafter more particularly
described.
Other features of the invention consist in the details of construction of the clamping
or work holding devices.
In the accompanying drawings
Figure 1 is a side elevation of a transformer secondary bar of a form which may be
employed in constructing an apparatus in accordance with the invention.
Figure 2 is a cross section of a form of apparatus embodying the present
invention.
Figure 3 is an end elevation of a modified form of transformer embodying the
invention, and shows in addition suitable means for regulating the current in the two
separate secondaries.
Figure 4 shows in side elevation one of the secondary bars illustrated in
Figure 3.
Figure 5 shows a modification in the means for regulating the current to the two
primary coils.
Figures 6 and 7 illustrate a modification in the disposition of the secondary bars
with relation to the work holding part of the apparatus.
Figure 8 illustrates diagramatically the manner in which the current flowing to
different parts of the work may be regulated when a transformer is employed.
Figure 9 is an end elevation of a modification of the invention wherein
four transformer secondaries are employed arranged circumferentially around the
work.
Figure 10 is a side view and partial section of a portion of the apparatus sbown
in Figure 9.
Figure 11 shows a modification in the clamping devicos.
Figure 12 illustrates a modification of the construction when four transformer
sucondaries are employed.
Referring to Figure 1 C indicates a secondary bar or conductor preferably made
as a casting of copper forming a solid copper bar having a groove in its side in which
the primary conductor P, may be wound, as shown in cross section in Figure 2. The
parts of the secondary C, at opposite sides of the slot or break a, form the poles or
terminals from which the current is taken for heating the work forming a bridge or
connection across from one side to the other of the break. Suitable clamps or holders
for the work are applied at opposite sides of the break and may be modified as to their
construction and arrangement in any suitable manner.
In making an apparatus in which two secondary bars or conductors shall be used
in accordance with the present invention, the two bars with their coils and cores
may be arranged as shown in Figure 2 at an angle with one another so that the flat
faces of the secondary bar will form the surfaces of a V-shaped bearing in which
the V-shaped clamp slide or work holder M, may he moved by means of a screw or
other device, as well understood in electric welding apparatus. In this case the

page_text: primaries and the cores therefor are separate structures. The primaries may be
connected into the circuit in any desired way. The current is taken up from both
secondaries and delivered to the work through the slide M, or other device which
serves to hold the work or to support it. The iron cores I may be applied in any
desired way and as usual are made up of laminae fastened together.
In Figure 3 is shown a construction wherein the two transformer secondaries are
arranged in substantially parallel planes and at a little distance apart and have their
edges bevelled or inclined to form a proper V-shaped bearing for the clamp slide M.
Here the secondaries have practically the same core 1. The iron bridge piece I'
connects the opposite sides of the cores between the two secondary bars. The two
primary coils are wound so as to magnetize the core proferably equally and in the
same direction and the lines of magnetic force circulate when the work done by each
is about the same, in a continuous magnetic circuit made up of the iron marked I.
The clamp slide M, is shown in the present instance as clamping the two sides of
a chain link K. The slide M. is preferably divided longitudinally so that the two
parts will be insulated from one another and will be furnished respectively with
energy from the two secondary bars (forming the two sources of electric
energy. The bridge piece is for the purpose of taking a part of the magnetic
lines of force when there is a variation produced in the flow of current in one of the
primary coils, as will be presently described.
Figure 4 shows in side elevation one of the secondary bars or conductors C, of
Figure 3 with the groove in its edge for the recoption of the primary conductor. In
the construction shown in Figure 3, the part 1 of the core only carries lines of force
which are caused to pass through the same on regulation. Practically the core is only
of the size which would he necessary for a single secondary bar or conductor.
It would be possible to magnetize the coro by winding the primaries thereof so that
all the magnetism would normally circulate through the piece I', but in such instance
the piece, would have to have a magnetic conductivity twice as great as the balance
of the core 1, and the construction would be, so far as bulk is concerned, not materially
different from two separaie iron cores.
In Figure 6 three separate transformer secondaries CCC are shown supplying
current in multiple to the same rest or plate which may carry the work or holders
therefor. The transformer secondaries Chere are shown as provided with separate
cores 1,1, though they might have a single core with intermediate bridge pieces 1' I²
applied after the manner indicated in Figure 7.
In Figure 9 I have illustrated my invention as carried out by the employment of
four separate secondary bars used in connection with a common work holding device
which is divided into sections insulated from one another to assist in the regulation of
the flow of current to different parts of the work. Here I have shown four secondary
bars C each having a separate core I. The work holding slides, four in number,
indicated at a are supported upon the ends of the secondary bars as indicated in
Figure 10 and slide in contact with the flat faces thereof. The several sections a of
the slide are insulated from one another as indicated. Working through each is a
clamp rod b, carried by the piston of the cylinder d. The cylinders d are secured to
a movable frame or ring G which may be moved when the work indicated by the
rod B is to be moved endwise in the welding or other operation. The clamps b
converge upon the work as indicated the latter being held in any ordinary lathe
chuck H, which serves merely to centre the stock no particular care being taken to
insulate such chuck or to convey current thereto. The current is conveyed to the
work principally through clamp jaws b. Pressure of any liquid may be conveyed to
the pistons of the cylinders d, through pipes as shown communicating with a common
pipe F. P is a three way cock or valve which may be turned to produce pressure
in pipe F by fluid from pipe F or to allow exhaust of pressure to take place through
a pipe T when the clamp jaws are to be moved back from the work by means of
springs in the cylinders d working against the pistons.
Figure 11 shows a similar clamping device wherein the clamp jaws consists simply

page_text: •
of screws working through the several slides. It is evident that two of the screws
may be kept in a fixed position after once setting for any sized stock, the other two
being used to allow the work to be put into place or reinoved. Stiff springs S between
the secondaries and a frame or backing S serves to press the secondaries towards
the slides and preserve uniformity of contact therewith. The secondary bars or 5
conductors instead of being provided with separate iron cores, as illustrated in
Figure 9, might have the same core or magnetic circuit, as indicated in Figure 12.
In order to regulate the heating of various parts of the work which is found to be
necessary when the work is large owing to the fact that different parts of the surfaces
in abutment are liable to heat unequally the energy flowing from the different sources
supplying the different parts of the work in parallel circuit should be independently
regulated. In the case of transformers this regulation may be readily effected by
regulating the current in the primary of the same.
In an apparatus such as illustrated in Figures 6 and 9 the regulation may be
obtained by providing each primary with a shunt containing a variable resistance, as
indicated at W Figure S. The primaries are indicated by the letter P and are
arranged in series with one another in a circuit from the source of alternating
currents D. Should it be found that one side of the work is heating faster than the
others, the adjusting device may be used to divert the current from the primary of
that secondary which is contiguous to the too rapidly heating portion thus decreasing
the flow of current at such part.
In regulating the current to different parts of the work in a construction such as
shown in Figure 3, an apparatus such as illustrated diagramatically in that figure is
preferably employed. In this figure G is typical of any source of alternating currents
which supplies the primaries of the two secondaries CC in multiple. The regulating
device operates after the manner of a reactive coil or counter-clectro-motive force
generator and is composed of an iron ring M2 preferably laminated and having two
coils A B¹ wound upon it at different parts and connected into the circuits of the two
primary coils.
O indicates a conducting band or circle of copper which encircles the core M² and
preferably consists of a copper casting. By varying the relation of this closed
conductor to the reactive coils, the reactive power of the latter upon the currents
flowing through them may be made to vary, as now well understood in the art, the
reaction being less when the conductor O, is over the coil A or B and gradually
increasing as it is moved away from coincidence with such coil.
I preferably provide in addition to the conductor O, an iron armature T which fills
the space within the core and coils A¹ B' and is preferably mounted on a sentre so as
to adapt it to form a support for the conductor O which by means of a suitable handle,
may be then moved to any desired position on the core and coils. The iron armature T
will obviously form an armature for the coils in whatever position the conductor O
may be placed. The coils A' B' are so wound or connected that the lines of force
generated by each in the core will tend to take paths shown by the arrows through
the armature T.
With this construction it is obvious that as the conductor O is moved towards one
coil A or B, and away from the other, the action of both coils will be simultaneously
varied. It is obvious likewiso that instead of a single conductor O, two conductors
might be employed, as indicated in Figure 5 one for each coil. The two conductors
would obviously act in the same way as the one conductor Figure 3.
The half link K or other device, the two sides or parts of which are to be heated
equally is placed in position on the clamp or clamp slide as shown in Figure 8 so that
each side or part will be supplied with current from a separate part of the apparatus
The coils of the two secondaries being so wound and connected as to act in the same
direction, the iron core will be magnetized with a difference of magnetic potentia
between 1 and 2 the same as between 2 and and the lines of magnetism will pas
from 1 to 3 directly and circulate through such core as a closed iron circuit, very
few if any going through the iron bridge 1.

page_text: Currents of equal potential will now be induced in the two sources of energy A,
B and will feed equal current to the two parts of the work, it being supposed that the
regulating devices are in proper position to permit current to flow in equal amount
through the two primaries. If now for any reason the left hand side of the work
should heat faster than the right, the reactive device would he adjusted by moving
the conductor O, towards the reactive coil B thereby decreasing the reactive effect of
that coil and increasing that of A' so as to increase the current in the primary of the
secondary feeding the right hand side. and decrease the current in the primary of the
left hand side.
The magnetic potential at the point 2, is thereby raised as compared with point 3,
and extra lines of magnetism will take a short path through the iron bridge and back
to their source. thus permitting the left hand side of the apparatus, to work freely in
setting up greater electrical energy under the influence of the alternating current.
It is obvious that the invention is not limited to any particuler number of different
electric sources independently controlled as described, nor to any particular construction
of transformer secondary.
The same plan of providing a single core for two sets of primary and secondary
conductor and furnishing a magnetic bridge piece I for operation as just described
might obviously be extended to any number of primaries and secondaries having the
same iron core. Thus as indicated in Figure 7 three secondaries are arranged in
parallel and supporting or connected to a clamp rest or support C which might be
used for holding or supporting a sheet of metal the edge of which is to be united to
the odge of another piece held at the opposite side of the slit in the secondary. The
support might be subdivided by insulation applied so as to divide the support
longitudinally in the same manner as indicated in Figure 3.
It is obvious that the construction of compound transformer for use in connection
with means for regulating the current in each part of the primary would be useful in
any case where it is desired to regulate the energy furnished from different parts or
sections of the secondary conductors.
It is obviously not necessary that the reactive devices should he constructed so that
the reaction in one branch or primary circuit will be diminished when that of the
other is increased and vice versa, but it would be possible in conjunction with the
transformer constructed as described, to vary the reaction of each device in each
primary independently of the others or to vary the current in such primaries in any
other desired manner. Thus for instance, as illustrated in Figure 7 the current
flowing in each primary may be regulated in the manner already described in con-
nection with Figure 8.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me
by my foreign correspondent I declare that what I claim is :-
First. The combination in an electric metal working apparatus, of a plurality of
transformer secondaries arranged as described so as to supply the electric heating
current to the work or work holding devices in parallel or multiple arc, as and for the
purpose described.
Second. In an electric metal working apparatus two secondary bars or conductors
having separate cores and arranged at an angle to one another, in combination with a
clamp slide or work holder working in the angular bearing formed by the outer
surfaces of the secondary bars or conductors substantially as shown and described in
connection with Figure 2 of the drawings.
Third. In an electric metal working apparatus, two or more different sources of
energy, such as the secondaries of transformers, arranged to supply the different parts
or portions of the work in parallel arc, and suitable means for regulating the energy
of the current supplied to different parts of the work so as to control the relative
heating thereof, as and for the purpose described.
Fourth. In an electric metal working apparatus, the compound transformer con-
structed substantially as described with two or more secondaries and corresponding

page_text: primaries applied at different parts of a common iron core provided with one or more
magnetic bridges etc.; and suitable means for regulating the current flow in the
primaries.
Fifth. The combination with the two primaries having their secondaries connected
to different parts of the work, of the two reactive coils in the circuits respectively of
said coils and wound on the same core, and one or more closed conducting bands or
circuits adjustable with relation to the coils as and for the purpose described.
Sixth. The combination with the separate parallel secondary bars or conductors
having a bevel at their inner sides, of a V-shaped clamp slide bearing on said secondary
bars at their beveled portion and having its two parts insulated or not from one
another in a longitudinal line, substantially as shown in Figure 3.
Seventh. In an electric metal working apparatus, the work holder having two or
more clamp jaws working on converging lines and insulated from one another.
Eighth. In an electric metal working apparatus, the combination with a work holder,
of a plurality of clamping jaws, a separate pressure cylinder for each jaw and means
for controlling the pressure in said cylinders simultaneously.
Do thi 10th 1 1800
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.