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

page_text: COMPLETE DIECIFICATION.
Improvements in the Method of and Apparatus for Electrically
Welding Metals.
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, 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 inven-
tion 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 mode of and apparatus for electrically welding.
metal, hereinafter fully described and claimed.
In the drawings:
Figure 1 is a perspective of the complete machine;
Figure 2 a front elevation with the base broken away;
Figure 3 a side elevation of the welding clamp block;
Figures 4 and 5 views somewhat exaggerated of the forms taken by the metal
in welding; and
Figure 6 a perspective view of one of the perforated clamp blocks.
J represents a case of any suitable material, in which is contained a transformer
or converter of any desired type, the secondary of said transformer or converter
being open and ending in the terminals A and A¹ on the top of case J. C and C¹
represent blocks arranged to slide upon the terminals A. A of the secondary, and
connected together by an insulated right and left hand screw threaded shaft S,
which is tapped into said blocks and which is provided with a hand wheel W
journaled in a post P, by which said clamps CC¹ may be brought together or
moved away from each other. D represents perforated clamp blocks, one of which
is carried in each of the sliding blocks C C', and this feature forms the subject of
a separate claim in an application No. 17224, dated September 27th 1892 filed
contemporaneously herewith. H and H¹ represent threaded bolts and hand wheels,
tapped through projections on the upper parts of blocks C C₁, and carrying at
their lower ends followers F and F', between which and the blocks D and D the
articles to be welded are clamped. ff represent guide rods on the followers F F¹
running through holes in the projection of blocks CC, and preferably encircled
by spiral springs, as shown in the drawing, to automatically raise the follower
blocks F F when the screw bolts H H₁ are turned outward. Of course the
screw bolts H H¹ may be connected with the follower blocks by a swivelled
connection, so as to both raise and lower said blocks positively. G represents a
post carried on, but insulated from, the bed J of the machine, in the upper part of
which is swivelled a right and left hand screw-threaded shaft S₁, provided with a
hand wheel H. Screw shaft S¹ engaged with two blocks K and K, which run on
guides on post G as shown in Figure 3, and the meeting portions of these blocks in
the line of the weld are formed to fit the articles to be welded, as clearly shown in
Figure 3.
The operation of the invention is as follows:-
The two articles to be welded, represented by M M', are clamped between the
followers F F and perforated clamp blocks D D', and then the blocks C C₁ are
brought together so as to bring said articles M M' nearly in contact, and absolutely
so if desired. By means of the screw shaft S¹, clamping blocks K K' are now
closed upon the articles M M' to hold them tightly, and to make connection between
them when not in contact. An electrical current is now passed. through the

page_text: converter in box J, by which the current passing through the terminals A. A¹ of
the secondary passes through the blocks CC, clamping blocks D D', and thence
through the articles to be welded, thus raising the temperature of said articles.
In this operation, the articles M M will tend to heat at the point marked NN,
when, by revolving screw shaft S, leaving clamps K K₁ firmly closed upon the
articles M M', the said articles are upset slightly at the points N N, as shown as
somewhat exaggerated at N N, Figure 4, thus forming a swelling on each side of
the joint, instead of a depression as is ordinarily the case in this process of welding.
The clamps K K' are now slightly separated by means of the screw shaft S', and
the articles M M', if not in contact, are brought in contact, and then pressed together,
or, if in contact, are pressed together, thus forming a weld.
Under the present system of welding by incandescence, when a current traverses
the joint directly, the burr is often quite large, the heated portion back of the
burr is short, and a re-heat and second upsetting are necessary to form the finished
weld. With this process, this re-heat is unnecessary, since the material is upset
previous to the weld, and, while still heated, the weld made. The material is
then in condition for swaging or drop-forging, having a sufficiently long heated
section, and this section containing sufficient metal to permit working without unduly
reducing its cross section. The upsetting also causes a somewhat larger volume
of current to play across the joint previous to the weld. When the articles M M'
are not in contact at the first upsetting, the clamps K K' furnish a path for the
current.
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 welding or working metals electrically,
consisting in heating the metal by passing an electric current therethrough,
upsetting each of said articles an appreciable distance back from the point of
welding, and not at the plane of junction, then bringing said articles in contact and
passing a heating current therethrough, and then pressing the two articles to be
welded together.
2. The hereindescribed method of welding metals electrically, consisting in first
heating the articles to be welded by passing an electric current therethrough, then
upsetting each of said articles an appreciable distance back of the place of welding
and not at the plane of junction, then pressing said articles together to form a
weld, finally completing the weld by swaging, hammering, etcetera.
3. The improved apparatus for electrically welding metal, combined and arranged
substantially as described.
Dated this 26th day of September 1892.
WM. P. THOMPSON & Co.,
Agents for the Applicant.