Improvements in the Method of and Apparatus for Welding or Heating Metals Electrically.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in the Method of and Apparatus for Welding or
Heating Metals Electrically.
A communication by CHARLES L. COFFIN, of Detroit, in the County of Wayne,
and State of Michigan, United States of America, Chemist.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, & 6 Bank Street,
Manchester both in the County of Lancaster & 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 :-
This invention consists of an improved method of and apparatus for welding or
heating metals electrically, hereinafter fully described and claimed.
The drawing is a perspective of an apparatus by which the invention may be
practised.
T represents the core of a transformer or converter of known construction,
of which P is the primary wound around the core, but insulated therefrom, and
connected with a generator of electrical currents, which may be either alternating,
pulsating vibrating or intermittent.
A, represents a portion of the core made movable, D represents a bracket
secured on core T and extending over the movable part A. of said core.
K repre-
sents a screw rod threaded through bracket D and swivelled into the movable
part A of the core, by which said movable part may be raised to make a gap
in said core. S represents the secondary of the transformer made heavy, and
purposely left incomplete, that is, with a gap in it as shown in the figure.
CC represent two clamps secured on a secondary S, at each side of the gap
therein. On one side of the gap a part of the secondary, marked S³, is made
movable, and its movement is controlled in any desired way, as for instance by
the bracket B, secured on secondary S, and provided with a screw rod or winch W,
threaded through said bracket and swivelled into the movable part S₁ of the
secondary S. I represents insulation. H represents a frame, or hoop or band.
In welding the ends of a hoop, or band, or any continuous piece of metal by
means of heating currents traversing the joint, the tendency of the current is to
pass around the hoop, etcetera, instead of crossing the joint, and this tendency
requires the interposition of some means to prevent the flow of current through
the materal. It is to obviate this difficulty that the present invention is
designed.
In proceeding to weld a continuous band or hoop, like H, the movable part A
of the core is raised and the hoop or band H is laid on the secondary S, its
ends brought in contact, and it is clamped to the secondary by the clamps C C.
The hoop or band H is usually laid directly on the secondary, though insulation
may be interposed between the secondary S and the band H if desired (except
at the clamp extremities) and in some cases it may be found advisable so to do.
The movable part A of the core T is now brought into contact with the core below
it, so as to complete said core, and then alternating or pulsating or vibrating or
intermittent currents are passed through the primary P. This induces current
of large volume and low electromotive force in the secondary S, and in the
band H, and as the band is parallel with the secondary S, and is, when no
insulation is used, essentially a part of said secondary, the current in the secondary
and in the band will be in the same direction, and the band will complete the
secondary, or bridge the gap therein, so that the current will tend to flow across
the joint instead of tending to flow around the hoop or band. The result is,

page_text: that the ends of the band or hoop H are rapidly brought to a welding heat,
when they may be pressed together by the winch W to form the weld, which
may be thereafter worked or hammered in any desired manner, or the hoop or
band H may be removed from the machine, and welded or worked in any
known way.
It is evident that the apparatus which is herein illustrated may be varied in
form or detail and these other forms used to practise the invention, as well as the
form illustrated.
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 the ends of a continuous
piece of metal consisting in closing a gap in the secondary of a transformer or
converter by the ends of the piece to be welded, (the said piece of metal lying
parallel at all points to said secondary) passing suitable currents through the
primary of the transformer, and pressing the ends of the piece together when raised
to a welding heat.
2. An apparatus for electrically welding continuous metal bands consisting of a
converter having a broken secondary, and means for inserting the piece to be welded
within the core of the transformer so as to complete said secondary, substantially
as shown and described.
Doted this 26th dox of Santember 1800
WM. P. THOMPSON & Co.,
Agents for the Applicant.