Improvements in or relating to Electrical Welding.
Year: 1891

page_text: Date of Application, 21st July, 1891-Accepted, 7th Nov., 1891
COMPLETE SPECIFICATION.
Improvements in or relating to Electrical Welding.
A communication from JOHN H. BASSLER, Engineer, of Myerstown, Lebanon
County, Pennsylvania.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., 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 contemplates an improved method of welding together heavy
plates of metal, such for instance, as boiler plates, and parts of structural metal
work, by means of electricity.
The invention consists in first coating the meeting edges of the plates to be
operated upon, with carbon; then placing those edges close together, then by
proper electrical conductors, sending simultaneously one current of electricity
transversely through the joint from the upper surface of the plates, and another
current transversely through the joint from the lower surface of the plates and
moving the plates in the direction of the seam with relation to the electrical
conductors controlling the direction of said currents, in order that the line of joint
may be subjected to the welding heat. This may be done by moving the conductors
instead of the plates.
In carrying out this method, there is applied to the meeting edges of the metal
plates, a small quantity of finely powdered carbon mixed with any suitable liquid
that will cause it to adhere to the metal. By applying carbon to the meeting
edges of the plates, the heat will be intensified at the joint, for as the carbon is not
so good a conductor of electricity as the metal itself, it follows that it will offer
resistance to the electric currents.
The electric currents are established by placing one pair of electrodes in contact
with the upper surface, near the meeting edges of the plates to be welded, and
another pair of electrodes in contact with the under surface, near the meeting
edges, the Tatter pair positioned substantially under the former, and both the
positive electrodes being in contact with one plate, while both of the negative
electrodes are in contact with the other plate, each pair of electrodes connected
with any suitable source of electricity.
By passing one current of electricity across the joint from the upper surface
of the plates and simultaneously, another across the joint from the lower surface, it
is possible to bring metal plates of considerable thickness to a welding heat in a very
short time.
This method is not dependent upon any mechanism other than such electrical
appliances as will readily suggest themselves, but for the purpose of making public
one convenient manner in which heavy plates may be easily manipulated, the
illustrated apparatus is arranged for carrying the plates forward, so as to bring the
line of joint in proper position to be welded.
Figure 1 of the drawings is a perspective view of the apparatus.
Figure 2 is a broken detail view, showing the positions of the electrodes with
relation to each other and to the plates to be welded.
Figure 3 is a modified form adapted to large work.
Referring to the drawings, A represents the rectangular framework, the four top
rails of which are grooved along the upper edge, as at a.
B B are two perforated bed plates, having runners 6 and 6* secured to their
under sides, which runners are so positioned as to rest in the grooves in the rails 1
and 2. Each bed plate is also provided on its under side with a rigidly attached
rack bar C, with each of which gears a pinion D, (only one of which is seen)

page_text: mounted on a shaft E, extending across the framework, underneath the bed plates,
and provided at one end with a crank handle F, the said shaft being journaled in
brackets attached to two uprights G, said uprights being connected at top by a
cross bar G⭑.
H H* represent two metal plates to be welded, they being secured in position on
the bed plates B B*, by means of clamps secured to the bed plates B B*.
I I⚫ are the two upper carbon holders, consisting simply of metal tubes, in which
the carbon electrodes J J* are secured by means of thumb screws ii*. These
carbon holders are held in proper relation to each other by means of metal straps S,
secured to the cross bar G, but are free to slide therein, and are properly insulated.
As shown in Figures 1 and 2 of the drawings, the positive electrode rests upon one
Wires K K lead from these
plate, and the negative electrode upon the other.
carbon holders to a source of electrical supply 1.
The electrodes may be jointed so as to adapt them to inequalities in the surface
of the work.
M M represent the lower carbon holders. These are separately insulated and
are hollow down to the base, and each is provided inside with a light helical
spring N, upon which the electrodes O O* rest loosely, so that the electrodes 0 0*,
may, by the reaction of the springs, be held up in contact with the under surface of
the plates H and H*. Their relation to the upper electrodes being clearly shown
in Figure 2. Those holders are of course, properly insulated at the base.
Wires P P lead from these carbon holders to another source of electrical
supply Q.
It may in some cases be preferable to bevel or scarf the edges of the plates as
seen in Figure 2.
When the metal plates H and H* are firmly secured in position on the bed plates,
with their meeting edges forced closely together, both currents are turned on by
closing their respective circuits, and as the plates become sufficiently heated in
the vicinity of the electrodes, they are moved forward slowly by turning the
crank F.
In large work, which work may not from its connection, be readily moved to
present it in different parts of the seam or weld to the action of the electrodes, the
work remaining stationary, the electrodes may be moved and guided by wheels U,
rolling upon a track V.
To obviate the difficulty of pressing the parts together in such case, a strip or
fillet R, of metal, is used, as shown in Figure 3.
The electric circuits are caused to pass through the plates H and H* and through
the fillet R, which from its small size, becomes highly heated and plastic and is
kneaded into intimate union with the plates H and H* by a roller W or any
equivalent means, and serves not only to facilitate the closing of the gap between
the parts, but by giving direction to the electric current through a short portion of
the seam, at the same time to render the heating more intense, and with arrange-
ment, more than two pairs of clectrodes and more than two electric circuits (as
shown in Figure 3) may be advantageously used and a third circuit may be
connected so as to pass through the fillet strip R, and through one of the carbon
electrodes as shown in the dotted lines in the figure, marked K¹ and K³, the effect
of intense local heating being increased by the greater resistance of transmitting
the several currents in multiple through the place of contact of the plates H and H*
and fillet R.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent, and in what manner the
same is to be performed, I declare that what I claim is :
1. The above described method of welding together heavy plates of metal by
means of electricity, which consists in first coating the meeting edges of the plates
with carbon, then placing those edges close together, then passing simultaneously
one current of electricity transversely through the joint from the upper surface of

page_text: the plates and another current through the joint from the lower surface of the
plates and moving the plates longitudinally with relation to the direction of said
currents.
2. The method of uniting parts of structural plate work, by first preparing the
parts and holding them in juxtaposition with open converging clefts between them,
next inserting a metallic fiilet of sufficient cross section to fill the cleft, of such form
as to undergo a flow or kneading of the metal in filling the cleft, next applying
distinct electric generators or transformers to the parts contiguous to the points in
contact with the fillet and connecting the opposite electrodes from both generators
or transformers to the fillet and finally pressing and kneading the fillet, when heated,
into contact and union with the sides of the cleft, substantially as set forth.
3. In an apparatus for electrically welding large pieces of metallic structures
together, the combination of a clamping mechanism, substantially as described, for
resisting the expansion and change of form during heating and application of
pressure, with two similar electrodes arranged to electrically connect both parts
involved in the seam, with independent sources of electric current a third electrical
connection arranged to complete the circuits from the opposite electrodes of the
electric generators to a fillet or strip inserted between the part involved in the
weld, and the mechanism for progressively pressing said fillet into the seam and
continuing the transmission of the electric current through said fillet and adjacent
parts, during the progress of the heating, substantially as set forth and described.
Dated this 21st day of July 1801
W. P. THOMPSON & BOULT,
Agents for the Applicant.