A New or Improved Method of and Apparatus for Electrically Heating or Welding Metal.
Year: 1893

page_text: Date of Application, 13th June, 1893-Accepted, 19th Aug., 1893
COMPLETE SPECIFICATION.
A New or Improved Method of and Apparatus for Electrically
Heating or Welding Metal.
A communication by CHARLES LEWIS COFFIN, of 980, Jefferson Avenue,
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 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 :-
This invention consists in a method of and apparatus for electrically welding
sheet metal, pipes, tubes; rings, tires or continuous metal articles hereinafter fully
described and claimed.
In the drawings:
Figure 1 is a side elevation:
Figure 2 is an end elevation looking from the left, Figure 1, omitting the frame:
Figure 3 is a section on line x-x, Figure 1; and
Figure 4 is an end view of a tube prepared for welding.
In preparing a tube for welding, flanges a a are turned up at the points to be
welded, and sufficient metal is thus obtained to make the joint, and also imperfect
contact is obtained on both faces with a single electrode.
A, represents the base of the machine, on the upper part of which is carried a
horizontal arm B, somewhat longer than the joint or seam to be welded. Below
the arm B and parallel therewith, a mandrel M is carried on frame A, to the other
end of which mandrel is pivoted one end of a link L adapted, when turned up in
the position shown in Figure 1, to hook over the end of arm B, and thereby support
said mandrel at its outer end.
JJ represent two conductors, each of which is hinged at one end to a lug H
carried on the frame A below arm B; and each of said conductors J is insulated
from the frame A and also from the mandrel M. The two conductors Y Y connect
the conductors J J with one terminal of a source of electric energy.
K represents
a link pivoted at one end to one of the conductors J and adapted to enclose the
other conductor when they are brought in the position shown in Figure 2, and thus
hold said conductors firmly pressed against the tube W when in position to be
welded. C represents a threaded shaft journalled in lugs bb formed on the arm B,
and provided with any convenient means for rotating the same, as for example a
pulley D. E represents a carriage or nut threaded and travelling on screw shaft C
when the same is rotated. The carriage E carries a conductor G, which is insulated
from said carriage as shown at I, and which is adapted to rest upon the upturned
flanges a a of a tube W, carried ou mandrel M. The carriage E also carries one
or two rollers F F in the rear of conductor G, which rollers are adapted to press
on the upturned flanges a a when carriage E is made to traverse screw_shaft C.
Any suitable means for forcing rollers F F towards the work may be used, and, as
this may be done by a screw or by a spring, or by a weighted lever, or in many
other ways, no particular device has been shown for this purpose.
The conductor G is connected by conductor X to the other terminal of the same
source of electric energy to which conductors J J are connected.
The operation of this invention is as follows:-
A sheet of metal which is to be welded is first bent into the form of a tube W

page_text: and its edges slightly upturned, as shown at a a, Figure 4. The carriage E being
retracted to its nearest position with reference to frame A, and the links K and L
being thrown out of engagement, the conductors J J are swung on their hinges
away from the mandrel M, and the tube W is slipped over mandrel M with its
edges a a directly in line with conductor G and rollers F F. The link L is now
thrown in the position shown in Figures 1 and 2 to support the mandrel (though
this link may be entirely dispensed with if the parts are made strong enough for
that purpose) and the conductors J J swung toward each other and locked by the
link K, thus clamping the tube blank W between said conductors and the mandrel M.
The carriage E is now moved forward until the conductor G comes in contact with
the upturned edges a a, when a heating current is passed through the conductors X
and G, passing through the edges a a, rapidly bringing them to a welding point,
through the material of tube W to the conductors J, and then back through con-
ductors Y, or vice versa. As the edges a a are brought to a welding heat, the
carriage E is advanced by rotating screw shaft C, bringing the conductor G in
contact with another portion of the flanges a a and the rollers F F, pressing the
heated portions a a down upon the mandrel as shown in Figure 1, thus welding
them together, and the operation thus proceeds until the flanges a a are welded
along their entire length, when the current is shut off, the carriage E retracted, the
welded tube W removed and another one put in position for welding.
The lower surface of conductor G may be made of various lengths for different
thicknesses of sheet metal so as to concentrate the heating effect of the current
upon such an extent of the metal to be heated as will permit the welding operation
to be continuous from one end of the pipe to the other.
It will also be noticed that the current is passed through the welding edges of
the pipe approximately in a direction or plane of their inclination, by which means
the edges or flanges are rapidly raised to a welding temperature.
While this invention has been illustrated and described as applied to welding a
sheet metal tube, it is evident that it is equally applicable to welding two sheets of
metal, as the clamping conductors J and mandrel M may be of any form desired.
It is also evident that, instead of forming flanges a a on both edges to be welded,
a flange may be formed only on one edge, in which case the lower surface of
conductor G may be made of such shape as to make contact both with the flanged
and unflanged edge simultaneously. The material to be welded after being heated
to the requisite temperature may be completed by either rolling pressing or
hammering.
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 heating or welding, consisting in
first flanging one or both edges of the metal along the proposed seam or joint,
clamping the two sheets to be welded between clamps connected with one terminal
of a source of electric energy, bringing the edges into contact with a conductor
connected with the other terminal of said source of electric energy; passing
heating current through said conductors and the material until the edges are raised
to a welding temperature and then completing the welding by rolling, pressing or
hammering.
a
2. The herein described method of electrically heating or welding pipe, or tube,
or ring, or continuous piece of metal, consisting in first flanging one or both edges
of the metal along the proposed seam or joint, clamping the two edges of the seam
or joint between a clamp and a mandrel connected to one terminal of a source of
electric energy, bringing the edges into contact with a conductor connected with
the other terminal of said source of electric energy, passing a heating current
through said conductor and the material until the edges are raised to a welding or
working temperature, then completing the welding or working by rolling, pressing
or hammering.

page_text: 3. In a machine for electrically welding metal the combination with a base of an
arm carried thereon, a mandrel supported on said base parallel with said arm,
conductors hinged to the base and adapted to clamp the material to be welded
against said mandrel and connected with one terminal of a source of electric
energy, a traversing carriage on said arm, an insulated conductor carried on said
carriage connected with the other terminal of a source of electric energy, and a
pressure roller carried on said carriage, substantially as and for the purposes set
forth.
4. In a machine for electrically heating or welding pipes, tubes, rings, tires or
continuous metal articles, the combination with a support, of an arm carried
thereon, a mandrel parallel with said arm, a conductor adapted to clamp the
material to be welded against said mandrel and connected with one terminal of a
source of electric energy, an insulated traversing conductor carried on said arm
and connected with the other terminal of the source of electric energy, a
traversing carriage carried on said arm, and a pressure roller carried on said
carriage.
DL: 10th T. 1002
WM. P. THOMPSON & Co.,
Agents for the Applicant.