Improvements relating to the Heating and Working of Metal Bars by Electricity.
Year: 1892

page_text: Date of Application, 17th May, 1892-Accepted, 2nd July, 1892
COMPLETE SPECIFICATION.
Improvements relating to the Heating and Working of Metal Bars
by Electricity.
I, GEORGE DEXTER BURTON, a citizen of the United States of America,
residing at Boston, in the County of Suffolk and State of Massachusetts, United
States of America, Electrician, do hereby declare the nature of my invention and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
My invention relates to the heating and working of metal bars by electricity,
and it consists in a new and useful mode of conducting the same substantially as
hereinafter described and claimed.
In the drawings I show certain apparatus for conducting the heating process, as
follows:
Fig. 1 is a perspective view of the arms and electrodes of the converter, with
the metal bar in place while being heated.
Fig. 2 is a side view of a metal bar after being heated and bent or twisted to
form a baluster.
Fig. 3 is a side view of another bar heated and bent to a different form.
Fig. 4 is a cross-section of the bars shown in Figs. 2 and 3.
A, A', are converter rings. This converter is connected to any suitable electric
dynamo in the usual way, and is so constructed to convert the current of the
dynamo of high electro motive force into a heavy current of low electro motive
force, as is customary in apparatus for heating and welding metals, and need not be
more specifically described here.
To the rings A, A', which are respectively positive and negative members of the
heating electric circuit, are attached the arms B, B', which carry on their outer ends
the slotted plates b, . In the slots of these plates the electrode clamps c, c', are
adjusted to the proper distance apart by the set screws c³, and c. Each electrode
clamps the bar d of metal, which is placed in them to be heated, and is clamped
down by the set screws and c in the framework of the clamps.
parts
If in this position the current were turned on, the bar would be heated throughout
its length between the clamps, starting from within a quarter of an inch inside of
each clamp, because the latter is made with bearing surface enough to prevent
heating between the surface of the clamp and bar. It is often more convenient,
however, to heat only certain parts of the bar between the clamps, which are to be
worked or bent, both because the unnecessary heating of the intermediate
requires more electric current and interferes with the bending or twisting of the
parts of the bar after the heating is done. I therefore place upon the centre of
the bar to be heated, on one side of it, a piece of copper, d, of considerable size
so as to make a good electrical contact with the face of the bar d, on which it
bears. When the electric current reaches the copper piece, d², it forms an enlarged
conductor to carry the electric current over the part of the bar on which it rests,
without the resistance to the current which it meets in the bar on each side, so that
this part of the bar so bridged over does not become heated to the extent of
the adjacent parts and, in fact, may be kept quite cool while they are raised to a
white heat.
When the bar has been heated I take it and by a single operation twist it into
the form shown in the finished baluster, e, shown in Fig. 2. This is done by
clamping one end into a vise and applying a wrench to the other end and turning
the bar, which causes the heated portion to form the spiral twists while the cool
end and middle portions retain their original shape. If preferred, one of the

page_text: heated portions may be twisted and the other bent so as to form the baluster, i,
shown in Fig. 3.
The number of parts of the bar heated may be increased by laying on it a
greater number of copper pieces, d, at intervals. It may be found expedicnt to
clamp two pieces, d, on different faces of the same longitudinal part of the bar d,
so as to afford a larger conductor to carry the electricity over that part of the
bar more effectively and prevent its heating, but the method of doing this will be
well understood.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
:-
The method of heating desired portions of a bar of metal spanning the space between
electrodes of opposite polarity, which consists in passing a heating current of
electricity through the bar and applying to a portion of the bar between the
electrodes while the current is passing therethrough a conductor which diminishes
the resistance of the part of the bar which it bridges over and retards or prevents
its being heated there, substantially as described.
Dated this 13th day of Wahre 1000
GEORGE DEXTER BURTON.
Witnesses:
JAMES P. WILLIAMS,
Salesman,
New York City.
A. C. LADD,
Bookkeeper,
21 Central Street, Medford, Mass.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.