Improvements in Apparatus for Electrically Welding and otherwise Working Metals.
Year: 1890

page_text: Date of Application, 23rd Dec., 1890-Accepted, 21st Mar., 1891
[Communicated from abroad by HERMANN LEMP, of Lynn, Massachusetts,
United States of America, Electrical Engineer.]
Improvements in Apparatus for Electrically Welding and otherwise
Working Metals.
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 :-
The present invention relates to the construction of that class of electric metal
working apparatus in which the work is heated by the passage of an electric current
and movement is given to the work while heated in the welding, upsetting or other
operation.
In order that the nature of my present invention may be more clearly understood,
brief reference will be made to the machine as used in the operation of electric
welding.
It is well known that this process of welding is generally a butt welding one,
although it is not by any means confined to that; and that longitudinal pressure is
applied to the metals to force the abutting ends together, at the time when the
current has caused the metal to become very hot and nearly or quite at the point of
fusion. In most cases this pressure is applied while the current is still Howing,
consequently it is necessary to have some means of carrying the current to the
metal at the same time that it is moving. Heretofore this has been done by
providing two parts with smooth polished surfaces, one sliding on the other, the
metal to be worked being clamped upon the sliding part and a connection made
between the other and the source of electric current. This necessitated very fine
mechanical construction of the surfaces, in order to lessen the resistance at that
point and avoid loss of power during the flow of heavy currents. In working with
heavy metals or large masses of metals, too fine construction is incompatible with
the rough usage that such a machine receives, and in time the parts become worn
and bent out of shape, so that new fittings are required.
The present invention avoids two important objections, namely, the requirement
of nice and careful construction of sliding contacts, and the necessity of making
the current carrying devices of heavy construction in order to stand the wear and
tear of usage.
A. noticeable difference between the style of clamps heretofore used and the novel
construction hereinafter described is in the relation between the current carrying
devices and the clamps for holding the bars, rods, or the like while under longi-
tudinal pressure, and also in the relation of the metals worked upon to the current
devices. In the old style of machine, the pressure was applied to the end of the
slide before mentioned, thus making serve both as current clamp and pressure
clamp.
In the present invention instead of securing the stock to copper blocks or pieces
sliding upon other blocks, the stock itself is slid past suitable current carrying
electrodes or contacts bearing on the stock and which remain stationary, and inde-
pendent mechanical jaws or clamps are provided which grasp the stock and serve to
hold it so that end pressure may be applied. By this arrangement the current
carrying clamps need be only large enough to carry the current without heating.
While it is preferable to use separate mechanical jaws or clamps for holding the
stock in place in the operation of applying, end pressure, it would be within the

page_text: invention to move the stock past the current carrying clamps or electrodes by any
means, as by hand.
The great advantage in the use of such devices as are herein mentioned is that
the wear and tear is principally upon parts which are easily and cheaply replaced,
and not upon surfaces which are not only difficult to make, but which must be kept
in perfect condition in order to work to the best advantage. Also the liability of
the several parts to heat and warp is greatly reduced, as is also the cost of construc-
tion and maintenance.
In the accompanying drawings:-
Fig. 1, illustrates a type of machine formerly employed.
Fig. 2, shows in perspective, a form of machine embodying the present
invention.
Figs. 3, 4, 5 and 6, are details of construction of the clamp and current carrying
electrodes bearing on the work.
Fig. 7, is a side elevation of another form of electric metal working apparatus
wherein a rubbing or sliding contact, between the work and current bearing or
carrying electrodes in direct contact therewith, is provided for in the operation of
rotating the work while included in the electric circuit.
Fig. 8, is a cross section through one of the uprights bearing the electrode or
plunger which bears upon the work.
Fig. 9, is an end view of the plunger.
Fig. 10, is a side elevation of a plunger in which provision for water-circulation
is made in a modified way.
In Fig. 1, 1, is the secondary of an alternating current transformer. It is formed
as a copper casting with a groove-in it to hold the primary coil, the iron core passing
through the opening in the centre. This arrangement of the three parts is illus-
trated in Fig. 2. Referring to Fig. 1, 2, is a V-block in which the bar or rod,
constituting the work, is securely-held by the gripping device 3. A rod connects
the lever with the V-block and this provides the means for longitudinal pressure.
This clearly illustrates how the current is collected from the secondary and given
to the stock, and also shows how easy it is for the V on the secondary to become
dirty or coated with grit, which impairs the contact, and causes heating when the
large currents flow, which-are-used in the work.
Referring now to Fig. 2, 4, is the secondary, 5, the primary-and-6, the iron core
of a transformer. 7, is an upright projection on a terminal of the secondary and
which is preferably an integral part of the casting which forms the secondary.
7ª, is a copper casting of the same form and dimensions as 7, but is capable of being
slid on the casting, and fastened in any position, by means of the screws 8, and 8".
The object of making this movable is to get variations of projection of the stock
beyond 7 and 7", according to the diameter of the bar welded, a feature indispensable
with good results in welding by electricity. Otherwise this part might be stationary
and is so during the welding operation. 9, is a steel plate with side guides which is
fastened to but insulated from 4. 10, is an ordinary centreing chuck which slides
on the plate and in the guides and grasps the work. Any other device might be
used for grasping or clamping the work to give it end movement. 10", is another
centreing chuck which is insulated from 7ª, but is secured to that casting, so as to
move with it when required. It will be noticed that the difference between the
right and left sides is this; that 10, may change its position with regard to 7, which
is stationary and that 10, does not change its position with regard to 7", but is
moved with it. It is to be understood that this precise mechanical construction is
not necessary, as in some cases it is desirable to move both chucks towards cach
other at once, in which case both sides would be alike; and it may be found
convenient to use an entirely different form of mechanical chuck.
The construction of the parts 7 and 7", is illustrated in the other figures. From
the inside surface of the round hole in these parts, and extending radially outward,
are made three holes equidistant apart; or in other cases more or less than three

page_text: may be used as desired. One of these is shown at 11, in Fig. 4. Extending the
length of these holes, and leading into them from the face of the casting, are
slots 12, and 12, Fig. 3. Fitting into the hole 11, is a copper rod 13, backed by a
spring 14, which tends to force the rod towards the centre of the large hole so as
to bear upon and make electrical connection with the work as bar '18, or 18". Steel
pin 15, is put through the slot 12, and screwed into the piece 13, allowing the latter
to be moved upward by any external means. 16, is a cam rotated by the handle 17,
on a collar surrounding the large hole, and serves to move all three pieces 13, 13, 13,
upward by bearing against the steel pins until these pins rest on the projections of
the cam, holding the rods 13, in a position farthest away from the centre. This
position is shown by the dotted lines. When the handle is moved to the position.
shown by the full lines, the springs force the rods towards the centre to the position
shown by the full lines Fig. 3.
Another means of accomplishing the same end is illustrated in Figs. 5 and 6.
In this instance the holes containing the rods 13, are connected from the outside to
a source of pneumatic or hydraulic pressure, which may be made to force the three
pieces toward the centre or upon removal of the pressure to allow the rods to move
back, each rod acting as a piston would. The operation of the machine is as
follows:-
-
Referring again to Fig. 2, if two bars are to be welded, the operator starts first
with the contact pieces or current bearing electrodes 13, moved outward and jaws
of the mechanical chucks apart and then push the bars 18 and 18ª, through, until
their ends butt against cach other half way between the parts 7 and 7", when the
jaws are closed tightly upon the bars. The handles 17 and 17", are now moved to
allow the rods 13, to come down on the bars and make contact with them. As the
mechanical chuck is insulated from the secondary of the transformer, it is evident
that the entire contact for the flow of current is made by these three pieces which
bear down rather hard by reason of the pressure behind them. As the current
heats and softens the abutting ends, the rods are forced together by means of any
mechanical pressure, as by pressure acting on pistons, the bar 18, sliding on the
three contact rods 13. The noticeable difference between this action and the one
illustrated in Fig. 1, is that the distance between the contacts representing opposite
polarity remains the same in the former, while in the latter it decreases as the
longitudinal pressure forces the bars together. But the principal advantage to be
observed is, that there are no sliding surfaces which must be kept in perfect order
free from dirt or grease, or the like. The contact pieces used are so simple and
cheap that they may be easily replaced when worn out. Also by using a number
of contacts arranged in a circle or around the stock, a better distribution of the
current is obtained, especially on large work.
In operations, especially upsetting and subsequent forging or shaping, it is
desirable to rotate the metal bar or rod in order to apply dies or proper cutters. In
Fig. 7, is shown the application of the invention to an apparatus suitable for this
purpose. 19, represents the bed or base of a lathe which is made in two parts
insulated from one another. The usual cone pulley 20, and chuck 10, are insulated
from the base, as is also the tail stock. This tail piece 21, carries a chuck 10",
which is rotatably mounted, and may revolve when a bar or rod as 18, is held by
the two chucks, and power applied to pulley 20. The uprights 7, and 7", are the
same in construction as in Fig. 2, and are electrically connected with a source of
current of large volume. This may be done by connecting cables 23, and 23", to
the two insulated parts of the base of the lathe and mounting the uprights upon
the base as shown, allowing them freedom of movement, for the same reason as in
Fig. 2. For this reason the screws 24 and 24", are provided to clamp the uprights
when in the proper position. The screw 22, provides end pressure for a welding or
upsetting operation.
In such an apparatus, the contact pieces, contained in the uprights 7 and 7ª, hear
upon and make contact with the bar in the same manner as shown in Fig. 2. The

page_text: friction of the rotating bar will add to the heat caused by the large amount of
current following from contact to bar, and therefore it is desirable to apply a cooling
fluid to the contacts, as shown in Fig. 8.
The same construction of contact may be advantageously used in the apparatus
when used for welding, as in Fig. 2. 7, represents part of one of the uprights as
shown in Fig. 5. The contact piece is made of two concentric tubes, 26 and 27, the
outer one forming a hollow stem or support terminating in a contact block 28. The
inner tube passes through the piston 25, (see also Fig. 9), leaving a small passage
from the top of the cylinder to the bottom by means of two tubes, all as shown. A
plug 29, closes the lower part of the cylinder, after the contact and piston is in
place, and an outlet 30, communicates with that end of the chamber.
When hydraulic pressure is admitted to push the contact downward, as before
explained in connection with Fig. 5, a certain amount of water escapes through
tube 27, dashes against the end 28, and passes out through tube 26, the holes
through the bottom and outlet 30. This keeps the contacts cool. Another method
is to drill a small hole through the whole length of a solid contact piece, like that
shown by 13, (Fig. 5) and let a small amount of water flow out the end and on to
the bar. Such a contact piece is shown in Fig. 10, the dotted lines representing a
small passage through the centre.
This invention is not limited to the particular forms of machine shown and
described as various mechanical variations in the details of the mechanism may be
used without departing from the spirit of the invention.
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. In an electric metal working apparatus, fixed current bearing electrodes
making contact with the work and through or by which the work slides in the
welding, upsetting or other operation, as and for the purpose described.
2. The combination in an electric metal working apparatus, of current carrying
slides or plungers bearing laterally on the work and mounted on a fixed support, and a
centreing chuck or mechanical clamp mounted on a longitudinally movable slide, as
and for the-purpose.described.
3. In an electric metal working apparatus, the combination with contact plungers
or rods (one or more) adapted to move laterally towards the work, of a spring for
forcing the same against the work, and a cam plate for disengaging them, as and for
the purpose described.
4. In an electric metal working apparatus, the combination with the secondary for
the transformer, of a block 7, at the terminal thereof, and a series of plungers 13,
mounted therein and bearing laterally upon the work, as and for the purpose
described.
5. In an electric metal working apparatus, the combination of the current carrying
electrodes bearing on the same and adapted to make rubbing or sliding contact
therewith, of means for rotating the work in contact with such electrodes, as and
for the purpose described.
6. In an electric metal working apparatus the combination, substantially as
described, with two rotary chucks or holders, means for imparting endwise move-
ment to one of said chucks, and current carrying electrodes mounted between said
chuck and the part of the work to be heated, and adapted to make rubbing or
sliding contact with the work when it is given an end movement, or is rotated.
7. In an electric metal working apparatus, an electric current conveying contact
adapted to engage the work laterally and having a solid contact end, and a pipe o
passage for delivering the cooling fluid against the inner side of the contact end, as
and for the purpose described.
8. The combination in an electric metal working apparatus, of an electric contact
a piston for forcing the same against the work, a hollow stem or support extending

page_text: from the piston and carrying said contact, a passage from the rear of the piston
whereby a cooling fluid, employed in operating the piston, may be brought to bear
upon the contact, and pipes or passages for withdrawing the fluid from the hollow
stem or support.
Dated this 12th day of December 1890.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.