Improvements in Welding Metals Electrically, and Apparatus therefor.
Year: 1890

page_text: COMPLETE SPECIFICATION.
Improvements in Welding Metals Electrically, and Apparatus
therefor.
A communication from abroad by CHARLES L. COFFIN, of Detroit, in the County
of Wayne and State of Michigan, United States of America.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street,
Manchester, both in the County of Lancaster, and 323, High Holborn, in the
County of Middlesex, Civil Engineer, 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 :—
The invention relates to electric welding, hereinafter fully described and
claimed.
The drawing is a side elevation of a machine which may be used to practise the
invention.
A and B represent posts which may stand on an insulated foundation. H H repre-
sent screw-clamps on posts A and B, which are to be insulated from said posts,
as indicated in heavy black lines, when said posts are not themselves insulated.
I and represent two pieces of metal to be welded together, securely held in
clamps H H, one of them, as J, being connected with the positive pole of a generator
of electricity by the conductor F and the other I being connected with the negative
pole of said generator by the conductor G.
The welding operation is performed by pressing the edges of I and J together, a
screw-rod N and follower O being indicated to suggest how this may be done, and
passing a current of electricity through the pieces IJ, by which their edges become
sufficiently heated to weld together under pressure.
My correspondent has discovered that by subjecting the joint between I and J to
the influence of a magnet acting across the path of the current while the current is
passing, the electrical resistance of the joint is secured and the heating effect of the
current becomes greater.
E represents an electro-magnet whose coil is connected by conductors M and L
with a source of electro energy. Of course the electro-magnet E may be a permanent
magnet. As it is frequently desirable to regulate the intensity of the magnetic
influence upon the joint, an easy way of doing this is indicated, magnet E being
shown as mounted on one end of the lever C, fulcrumed to post B at K, and the
other end of said lever C being provided with a handle D, by which means the
magnet E may be moved toward or away from the joint. It is found that, after
the two pieces have been joined together, a better weld may be obtained by ceasing
to press the joint together and applying strain tending to separate the joint (taking
care not to exceed the strength of the weld,) the current being still passing. This
increases the electrical resistance of the joint, and consequently increases the heat.
This force is only applied for a short time, and the joint is finished by rolling or
hammering.
My correspondent is aware that the use of a magnet in welding with the voltaic
are for the purpose of increasing the power and length of the arc is shown in
a United States Patent to De Bernardos, No. 388245, dated August 21st 1888 and
he does not herein claim that invention.
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 :-
1. The herein described method of electrically welding together two pieces of

page_text: metal consisting in pressing together the two pieces to be welded, traversing the
joint between the two pieces by an electrical current, and submitting the joint to
the influence of a magnet acting across the line of the current.
2. The herein-described method of electrically welding metals, consisting in
pressing together the articles to be welded, traversing the joint by an electrical
current, submitting the joint to the influence of a magnet acting across the line of
the current, stopping the pressure and subjecting the joint to a force tending to
separate it, and finally completing the weld by hammering or rolling.
3. The apparatus for welding together two pieces of metal, and subjecting the
joint to the influence of a magnet, acting across the path of the current, the whole
combined and arranged substantially as herein described.
Dotad this 5th day of May 1900
WM. P. THOMPSON & Co.,
Agents for the Applicant.