Improvements in Electric Welding.
Year: 1890

page_text: Date of Application (in United Kingdom), 22nd May, 1890
Complete Specification Left, 22nd May, 1890-Accepted, 2nd Aug., 1890
COMPLETE SPECIFICATION.
Improvements in Electric Welding.
I, CHARLES LEWIS COFFIN of Detroit, County of Wayne, State of Michigan, United
States of America, Chemist 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 invention consists in a method of and apparatus for treating metals by electricity,
hereinafter fully described and claimed.
The drawings are diagrams illustrating my invention :-
Figure 1 showing it applied to the method in which the arc is formed between the
two edges to be welded together.
Figure 2 showing it applied to that method in which a voltaic arc is formed between
the articles to be welded and an extraneous conductor.
D and E represent two pieces of metal to be welded together by passing a current
of electricity through them, and thus heating their meeting edges by establishing
a voltaic arc between them; but as they are not in contact it is ordinarily necessary
to bring them together to establish the circuit and separate them to spring the arc,
and this must be repeated whenever the arc breaks. To obviate this necessity is the
object of my invention.
A represents an electrical conductor connected with one pole of a generator of
electricity and connected with the bobbin of an electro-magnet B, the other end of
which (represented by C) is connected with the piece of metal D.
T represents an electrical conductor, which connects the piece of metal E with the
other pole of a generator. Were the circuit closed, the current would pass
through A B C D E T, as indicated by the arrows; but being open between D and E
the current cannot pass unless some means of closing the circuit is provided. This
I provide by the following means:-
H represents an induction-coil, the primary of which (represented by the binding-
posts ML) is connected with the conductors YJ from battery I, and whose secondary
(represented by F G) is connected with the pieces of metal D and E to be
welded.
U represents a vibrating circuit-breaker connected with the induction-coil. One
of the connections of the secondary winding of the induction-coil H (the one
marked K F) is connected with the two contact-plates R Q, by which the con-
nection F is broken, except when plates R Q are connected to prevent the welding-
current from passing through and destroying the secondary coil of the induction-
coil H.
S represents a circuit-breaker consisting of a lever pivoted at N to the base on
which electro-magnet B rests, and one end P is.in proximity to the end of the core of
said electro-magnet, while the other end a, which overbalances end P, rests normally
on the contact-pieces R Q, thus closing the connection F.
In Figure 2, W represents a conductor, with which are connected the conductor T

page_text: and the connection G of the induction-coil, precisely as these are connected with the
metal piece E in Figure 1.
is an insulating-handle by which conductor W may be manipulated.
The operation of my invention is as follows:-
A current being turned into conductor A remains inactive because it cannot cross
the interval between D and E; but the action of the induction-coil H causes a spark
to pass between D and E, thus affording a pathway for the main current, which
instantly passes through A, B, C, D, E, and T, forming a voltaic arc between D and E,
which rapidly brings the ineeting edges of D and E to a welding heat. As soon as
the circuit is thus established, the current energises the electro-magnet B, the core of
which attracts the'end P of bell-crank lever S and raises the end a of said lever away
from contact-pieces R Q, so that the current cannot flow through the induction-coil.
If for any reason the arc between D and E breaks, the circuit is broken, magnet B
no longer attracts end P of lever S; and the end a of said lever again connects the
contact-plates R Q, when a spark instantly passes between D and E, the circuit is
re-established, and lever S again attracted by inagnet B. When the connections are
inade, as shown in Figure 2, the spark and are pass between D and W instead of D
or and E.
t:
"I have illustrated an' induction-coil as the means for passing a circuit-establishing
spark between D and E; but any known electrical apparatus which is capable
of performing the same function, namely, causing a spark between D and E-is
for the purposes of my invention an equivalent of the induction-coil. 'When the
ends of D and E are sufficiently heated, they are welded by being pressed. together,
the current being stopped or not at will, and the weld may be finished in any known
mode, as by hammering, rolling, etcetera.
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 I
claim is
1. The herein described method of welding by electricity, consisting in connecting
the articles to be welded with the poles of a generator of electricity in open circuit,
closing the circuit by causing an electric spark to pass the break in the circuit, and
bringing the articles together to form the weld when sufficiently heated.
2. The herein-described 'method of welding metals by electricity, consisting in
connecting one of the articles with the poles of a generator of electricity, placing
a conductor connected with the other pole of the generator in proximity to the edges
to be welded, leaving the circuit open, and forming a path for heating currents
between one of said 'articles and said conductor by causing a spark from an indepen-
dent source of electrical energy to pass the break in the circuit, whereby a voltaic are
is formed in the break in the circuit.
3. In an apparatus for welding metals electrically, the combination, with two
pieces of metal not in contact with each other, of electrical conductors connecting
said metal pieces with the poles of a generator of electricity, an electro-magnet
included in one of said conductors;a generator of high-tension currents connected
with said metal pieces, and a circuit-breaker in the circuit of said high-tension
-generator, controlled by said electro-magnet, substantially as described.
Dated this 21st day of May 1890.
'WM. P. THOMPSON & Co.,
'Of' 6, Lord Street Liverpool, Agent's for the Applicant.