Improvements in Welding or otherwise Working Metals by Electricity, and in Apparatus therefor.
Year: 1890

page_text: Date of Application, 19th Aug., 1890-Accepted, 20th Sept., 1890
COMPLETE SPECIFICATION.
[Communicated from abroad by Professor ELIHU THOMSON, of Lynn, Massachusetts,
United States of America, Electrician,]
Improvements in Welding or otherwise Working Metals by
Electricity, and in Apparatus therefor.
I, HENRY HARRIS LAKE of the firm of Haseltine, Lake & Co., Patent Agents
45 Southampton Buildings in the County of Middlesex, 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 :-
My invention relates to the forming and welding of metals generally: It consists
in a novel process hereinafter described consisting in passing through the metal a
current of sufficient volume to soften or render the same plastic and then swaging
the metal into the form desired in a drop press.
My invention consists further in the novel process hereinafter described of forming
or forging metal consisting in applying pressure to the metal while heated to plasticity
by the passage of an electric current and then swaging the metal while still hot
from the electric heating into the form desired by a swage applied in a line transverse
to the said line of pressure.
My invention is especially applicable to the formation of a finished joint between
two metal pieces, and in this application involves the employment of the process of
welding followed by the swaging of the joint into form under a drop press applied
transversely to the line of welding pressure, while the two metals are still hot from
the electric heating and at the welding temperature, thus involving but a single heating
in the production of a finished joint of any desired form.
It is essential that the metal be kept at the welding temperature during the use of
the drop press or striking die. The faces of the drop and the anvil on which the pieces
are struck are made to conform to the desired shape of the pieces after joining and of
course these may be varied very widely without departing from the limits of my
invention, which consists in heating and at the same time welding two bars electrically
and while the bars are still at the welding heat swaging them into the desired form
by swaging or shaping dies applied from above or from both above and below. The
metal must be plastic and weldable when the drop form comes down upon it in order
to prevent creases or "cold shuts" being driven into the metal or existing at the
joint. I prefer, therefore, to combine some good form of drop press and electric
welding apparatus or device for feeding to the work very heavy currents of electricity.
This combination of apparatus I find not alone confined to use in welding of pieces of
metal, but it may be employed also with benefit to heat pieces locally for dropping
into shape, though I have particularly applied it to the formation of joints between
electrically welded bars or metal pieces.
A further object of my invention is to avoid the production of a burr or expansion
at the weld between the two metal pieces joined thus securing a better finished
joint.
To accomplish this object I propose to apply lateral pressure, hammering, or other
force, or other shaping or forming operation to the weld at the point where the lateral
burr or expansion tends to form, simultaneously with the application to the pieces
while heated by the electric current, of the pressure in a way which tends to cause a
swelling or lateral bulging of the metal at the proposed joint.
The lateral pressure or compressing operation may be performed by means of
hammers or dies, applied at various points around the joint which is being formed, in
a direction to compress or confine the metal while it is under pressure for welding so as
to tend to swell the metal at the joint, and while the current is applied which heats
the joint, up to the welding temperature. In this way as soon as any expansion at the

page_text: joint begins to take place the hammering or forming apparatus, such as hammers or
dies, reciprocating in all directions around the welded metal, or metal to be welded,
drives back the metal or condenses the stock in such a way as to prevent the metal
from actually producing any swell at the joint, and at the same time to secure a perfect
interweaving or welding at the joint.
The electric current may be fed intermittently during this operation for heating the
pieces, or it may be continually applied during the whole operation for keeping the
joint or adjoining portions at the welding temperature.
In the accompanying drawings,
Fig. 1, shows in side elevation a combination of apparatus suitable for practising
my invention and comprising a source of heavy currents for heating metal pieces
placed in suitable clamps, means for moving the pieces together to form the joint, or
to swell the metal at the joint or between the clamps when no joint is formed, and a
heavy shaping drop or former coming down upon the work or striking the work
while it rests in the clamps upon an anvil so as to give it the desired shape.
Fig. 2, is an end elevation of a part of the apparatus in position when the blow is
struck.
Figs. 3 to 15 inclusive, show various kinds of work and details of the operation
performed by means of the apparatus shown in Fig. 1.
Fig. 16 shows the appearance of a butt weld between two pieces such as is made
by my improved process of applying lateral impact or pressure during the end pressure
and electric heating.
Fig. 17 shows the appearance of an electric weld made without hammering in which
the burr or expansion has been allowed to form.
Fig. 18 shows in side elevation a form of apparatus useful in practising this part of
my invention.
In Fig. 1, S, S, is a U shaped heavy copper secondary supplying currents to metal
pieces B, B¹, held in suitable clamps (, C. One or both of said clamps are movable
and one at least must be movable in order to practise that modification of my
invention which involves pressure combined with striking in a line transverse to the
pressure. The conductor S, S, may be replaced by any other device capable of
feeding very heavy current to the clamps and through the metal between them.
I have simply indicated it as the secondary of an induction coil whose primary is a
coil P, P, fed by alternating currents of proper character from any suitable source.
The clamps C, O, are suitably supported so as to heat the bars B, B', in the position
shown, slightly above the anvil or lower frame A, which is in line with an upper
hammer or drop D, for striking the metal into shape after the pieces have been heated
or welded at the point J, between the clamps C, C'. The mechanism which raises
and lowers the drop or shaper D, may be anything practicable for the purpose.
I have simply indicated an ordinary strap or belt drawn over a friction pulley constantly
rotating, being driven by a driving pulley P, from the shaft above. The drop D,
moves of course in a frame F, F1, which guides it and causes it to come down
squarely upon the work, delivering a quick and forcible blow upon the hot metal
pieces. The parts of the drop are made suitable to the work to be done especially the
shape of its lower end, which of course may be made removable and replacable by
different forms of dies, as may also the top of the anvil A, a procedure usual in
connection with drop press mechanism. The one clamp C, is made movable towards
and from the other clamp C', in order to form the abutted pieces B, B1, or to allow
them to move towards one another where they are to be heated and welded, or to
apply pressure to the metal where the pieces B, B¹, are replaced by a single metal
piece, joining the clamps C, C8, so as to make a swell or expansion in the metal.
Where this swell or expansion is not needed the clamps C, C', may be made fixed in
position.
In Fig. 2, the section of the bar or piece B, is shown to be compressed between the
drop D, which has descended and the anvil A which is immediately below the bar B,
without being in actual contact therewith until the blow is struck; indeed the anvil A
may be made movable towards the drop D, in any suitable manner so that the blow

page_text: may be struck from both sides upon the metal.
This is a matter of mechanical
detail which is not necessary to dwell upon. When the pieces are to be welded under
the drop the part D, is raised and sustained in an elevated position. The bars B, B',
are put into the clamps slightly clearing the lower anvil A, preferably, and abutted
fairly well. The current is put on while the pieces are being pressed together at the
joint J, and gradually the joint attains a welding heat as well as a section of the bars
on each side of the joint. At this moment the drop D, is allowed to fall and
completes the work after which the welded piece may be removed for the insertion of
others which are to be treated in the same manner. One of the ways of preparing
the ends of the pieces is shown in Fig. 3, the two ends being slightly scarfed or
slightly tapered before welding between the drop D, and the anvil A. It is found
that this preparation, which is shown in a still more exaggerated form in Fig. 4,
produces a partial lap and a partial butt weld of very great strength and uniformity.
Fig. 5, shows how the pieces are pressed together when they become plastic and
before the descent of the drop. They-tend to ride up a little upon the other on
account of the slanting surfaces. As soon as the welding heat is reached the descent
of the drop welds and completes the joint. For butt welding the pieces may be
prepared with a rounding surface as in Fig. 6, placed in contact and afterwards
pushed up to form a burr or expansion, Fig. 7, before dropping. It is advisable,
however, in welding, not to form too great an expansion of this kind and it is also
desirable that the clamps C, C', one or the other be movable toward the other when
the drop comes down so that the metal may spread endwise during the formation or
shaping of the bar. This latter precaution may be entirely obviated by striking the
pieces when they have attained, from the shapes shown in Fig. 6, a partial butt weld,
indicated in Fig. 8, a slight depression existing around the joint or metal section
which, when the drop descends, is completely filled up with the hot and plastic metal
at the welding temperature so as to give a finished and smooth surface, as in Fig. 9.
By making the surface of the drop and anvil more complicated in outline almost
any form of work may be accomplished. Thus two joints Fig. 10, a, b, may be
struck at one operation into the desired form. In welding curved work such as
rings or tires the preparation of the ends and treatment is the same as before
mentioned except that the curved surfaces of the drop take the place of those
shown for straight surfaces in Fig. 1, or rather the form of the drops or preparation
of surfaces is made to conform to the shape of the ring or tire Fig. 11 and Fig. 12.
In giving any desired conformation to a piece of metal which is continuous
between the clamps the operation is similar. The pieces of metal as a bar having
been placed in the clamps are suitably heated by the passage of current, is given
a swell in the middle, as in Fig. 1, by the application of end wise pressure by means
of the clamp C, after which a suitably shaped drop and anvil between which the
metal is struck while heated in a direction transverse to the line of pressure gives
the swelled portion the modified shape or conformation shown in Fig. 14, or any
other desired shape according to the conformation of the die surfaces of the drop
press.
For forming a butt welded joint of good finish such as indicated in Fig. 16,
I proceed as follows:-The apparatus may be such as shown in Fig. 1, or any other
form of welding apparatus such for instance as that indicated in Fig. 18, where
C, C², indicates any form of conducting clamps or holders adapted to hold the pieces
to be welded and connected in any proper manner with any source of electric current
of sufficient volume to heat the pieces at the joint to the temperature required for the
welding operation.
The clamps are properly mounted so as to be insulated from one another and one
or both are provided with a screw or other device by which it may be forced towards
the other so as to weld the pieces in the clamps at the joint between when the joint
has reached the welding temperature by the heating effect of the current passing
through the pieces and across the joint.
Devices for applying pressure simultaneously with the heating and swelling laterally
at the weld are indicated at D, B, Fig. 18 and may be reciprocating hammers or

page_text: pressure dies applied to the metal at the weld, or other devices for reducing or
compressing the weld by pressure or impact laterally to the swelling metal at the
joint, my method being distinguished by the simultaneous application of this
compression influence at the same time that the pressure is exerted to move the
clamps towards one another during the process of welding by the electric current.
D, might be a hammer and B, an anvil and both may be moved circumferentially
around the weld to apply the pressure or impact over the whole weld.
The lengthwise pressure and the simultaneous sidewise hammering or pressure
during heating by the current by any instrument adapted to apply the pressure or
compression sidewise to the joint either over its whole surface at one or to parts
successively. The clamps that hold the pieces may be made to move in any desired
direction as in arcs of circles or in straight lines one towards the other. The hammers
may strike radially or at an angle with the line of the pieces it being only required
that they beat back the material or metal which is tending to swell out at the joint
and thereby complete the weld and also the shaping at the same time. The special
devices may be hydraulic dies or such like devices to compress together and form
the metal.
While I generally prefer to apply the lateral compressing or condensing force while
the current is continually or intermittently passing so as to insure the retention of a
good heat and welding condition in the metal, I do not limit myself in this respect
and it would be within the broader scope of the invention to take off the electric
current at the time of each application of the lateral impact or pressure provided said
impact or pressure be applied before the metal loses its welding temperature and the
current be renewed immediately after so as to keep up or restore the temperature.
Having now particularly described and ascertained the nature of my 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 process of forming metal into any desired shape, consisting
in placing the metal into an electric circuit between two clamps, holders or abutments,
passing an electric current through the same in volume sufficient to heat the metal to
plasticity, communicating end pressure to the work in a line parallel to the line
joining the clamps or holders, and then swaging the metal while still heated and
retained in position between the clamps, holders or abutments, into the desired form
by devices applied in a line transverse to a line joining the holders and conforming
to the desired shape of the metal.
2. The combination substantially as described, in an electric metal working
apparatus, of two clamps or holders adapted to hold a piece of metal between them,
means for imparting movement of one holder towards the other so as to subject the
work to end pressure while heated by the electric current passing through the work from
one holder to the other, and a metal swaging or forming apparatus the anvil and tool
of which are arranged respectively at opposite sides of the line joining the clamps or
holders and in position to engage the work in the clamps, as and for the purpose
described.
3. The combination, substantially as described, of an electric welding apparatus
having means for moving one of its clamps or holders towards the other, a swaging
apparatus the anvil and die of which are arranged at opposite sides of the line
joining the clamps of the welding apparatus and in position to engage the part of the
work in position between the clamps of the welding apparatus, as and for the purpose
described.
4. The combination, substantially as described, in an electric metal working
apparatus, of two clamps or holders connected with a source of heavy currents
and provided with means whereby end pressure may be communicated to the
work while heated between them, and a drop press the anvil of which is
arranged to one side of the line joining the clamps and in proximity to the work
held in the clamps.
5. The herein described improvement in electric welding which consists in abutting

page_text: two pieces to be welded, applying an electric current for heating the metals at the
joint of intended union and during the heating and welding of the pieces applying an
end pressure to force them together simultaneously with a shaping or compressing
lateral impact or pressure by compressing dies, or hammers, or other means whereby
an expansion at the joint is prevented and the joint is completed at the same time as
the welding.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.