Improvements in Electric Welding.
Year: 1890

page_text: Complete Specification Lert, 22nd May, Toy Accepted, and
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 inven-
tion 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 of a method of welding metals electrically, hereinafter fully
described and claimed.
The drawings illustrate mechanism which may be used to practise my invention :-
Figures 1 and 2 being perspective views,
Figure 3 an elevation of a portion of the mechanism, and
Figure 4 a small top plan view of a portion of the conductor-support.
The principle of my invention consists in heating the edge of an article to be
welded by passing a heating-current of electricity through the articles near the edge
to be heated.
N represents a table usually of some insulating material, as wood.
U and S represent clamps supported on said table.
In the mechanism shown in Figure 1, the article to be welded is connected with
one pole of a generator, while with the mechanism shown in Figure 2 it is not so
connected.
Referring to Figure 1 :-
A and B are two metal plates to be welded, the plate A being connected with the
conductor B¹ and binding-post G with one pole of a generator, while the plate B
is connected by binding-post G₁ and conductor A' with the other pole of a
generator.
C represents a block provided with a handle D and resting on two rollers I and J,
preferably of insulating material, which run on the articles on a metal plate A and B.
(shown in the drawings.) If the wheels I J are not of insulating material, they
should be in some way insulated from block C.
E and F represent two conductors, (carbon, for instance,) which pass through
block C, being insulated therefrom by the insulating material o, and rest upon the
plates A and B.
h and i represent electrical conductors, which connect the carbons E and F with
the poles of a generator of electricity. The conductors B₁ and i must be of opposite
polarity, and the conductors A' and h must be of opposite polarity; but with this
limitation it is immaterial how said four conductors are connected with the poles of
the generator or generators which supply the current.
The operation of my invention is as follows:-
Assuming conductors A¹ B' to be connected with the positive pole of a generator,
and the conductors h and i to be connected with the negative pole, the current flowing
in through conductor A¹ will traverse binding-post G¹, plate B, and conductors E
and h, thus heating the edge of plate B at its point of contact with conductor E.
The current entering through B will traverse plate A and conductor F_and_i,
thus heating the edge of plate A at its point of contact with conductor F. By
1.

page_text: means of the travelling block C, the conductors E and F may be moved along the
plates B and A to heat the whole edge of each plate, and when said edges are
brought to welding heat, the weld is formed by forcing the plates A and B
together.
As shown in Figure 2, the articles A and B to be welded are not directly con-
nected with the generator; but, instead of this, the conductor B₁ is connected with
the conductor q similarly to and opposite conductor F, and the conductor A¹ is
connected with a conductor p similar to and opposite conductor E, the two pairs of
conductors Fy and E p being brought into contact with the point of contact with
the conductors as above described.
For the purpose of readily bringing the conductors in contact with the .articles
to be welded, any suitable mechanism may be followed. That which I have illustrated
as an example is a standard j, supported on and rising from the table N and having
a dovetailed groove in its forward side.
f and g represent two blocks, the ends of which are fitted to engage with the
dovetailed groove in standard j, and which may be brought together or moved apart
by the right and left hand screw-threaded shaft K, tapped through both of said blocks.
The conductors E and F pass through and are carried by the block g, all of said
conductors being insulated from the block which carries them by a ring of insulating
material o, as shown in Figure 4. It is evident that, by turning the screw-shaft K,
the four conductors E, F, p, and 9 can be brought into or turned out of contact
with the articles A and B.
For pressing A and B together to form the weld, any suitable mechanism may be
used; but that which I have illustrated is as follows:-
The lower part of clamp S has a grooved extension Q, terminating in an upright
arm. The upper part of said clamp S, (marked T) is adapted to slide in the groove
in the extension Q. P represents a screw-shaft swivelled in the upright arm R and
tapped into the movable part T of clamp S. O represents a crank by which screw-
shaft P can be turned. Rotating said screw-shaft P moves clamp T longitudinally,
whereby the article B may be pressed against or withdrawn from the article A. To
permit either A or B to slide freely between the conductors, the arrangement of
Figure 3 may be used, in which the conductors E F pq terminate in rollers, which
permit either A or B to slide backward or forward while in contact with said
conductors.
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
The herein-described method of welding metals electrically, consisting in separately
heating the edge of each article to be welded by passing a heating-current through
said article in proximity to the edge to be welded and forming the weld by pressing
the heated edges together.
Dated this 21st dar
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.