Improvements in and relating to Electrical Apparatus for Forging, Welding, and Soldering Metals, and to the Manufacture of Rings, Links, and the like.
Year: 1888

page_text: [Communicated from abroad by ELIHU THOMSON, of Lynn, Massachusetts, United
States of America, Electrical Engineer.]
Improvements in and relating to Electrical Apparatus for Forging,
Welding, and Soldering Metals, and to the Manufacture of Rings,
Links, and the like.
I, HENRY HARRIS LAKE of the firm of Haseltino Lake & Co., Patent Agents,
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 generally to apparatus for metal working operations such as
welding, forging and the like in which electric currents of large volume or
quantity, caused to pass through the metal to be heated, are employed as the heating
agency.
My invention consists in the combination with a dynamo electric machine of any
suitable construction, of suitable clamping devices for holding the metal to be welded,
forged or otherwise treated in the desired position, such clamps or holding devices
being connected directly with the part of the dynamo machine in which the welding,
forging, or heating currents are generated and all being mounted together on a proper
frame and in convenient proximity to one another.
My invention relates also to means for automatically cutting off the current from
the metal when the welding or forging operation is completed.
My invention also consists in particular details of construction such as will be
hereinafter described.
By my invention I provide an apparatus which is compact, is readily transportable,
owing to the direct combination of dynamo generator with clamp devices, is easy
of manipulation and regulation, and at the same time is economical of current owing
to the fact that the clamp devices are connected directly with the original seat of
currents and without the intervention of long conductors. There is hence also a
saving in material over previous electric welding and forging apparatus.
The apparatus also generates its own current which is a condition obviously desirable
and necessary in a portable apparatus designed to work where other sources of current
cannot be obtained for exciting the machine.
I will describe my invention in connection with the accompanying drawing and
will then indicate what I regard and claim as my invention in the claims at the end
of the description.

page_text: I term my apparatus a direct electric welding or forging machino in order to dis-
tinguish the same from previous apparatus of the same general nature in which tho
currents derived from a generator are passed through a converter or induction coil
and the latter sets up the currents of large volume which are conveyed to the holding
clamps of the apparatus.
Figure 1 is a front elevation of a convenient form of my improved "Direct
Electric Welding and Forging Machine."
Figure 1 shows a detail of construction.
Figure 2, is a side elevation of the same apparatus, showing a partial section of the
field magnets and armature and an end view of the holding clamps.
Figures 3 and 4, show the field magnets respectively unwound and wound.
Figure shows the manner of winding the fields.
Figures 5 and 6, show details of the construction of the field magnets, and
Figure 7 shows detail of winding.
Figure 8 is a view of the laminated core of the armaturo.
Figure 9, is an end view of the armature unwound.
Figures 10 and 11, shows two forms of armature windings in perspective.
Figure 12, showing one of these windings in section.
Figure 18 is a perspective view of the connections, between the fickt exciting circuit
and the field magnets.
Figure 14 is a perspective view of the form of contact plate which conveys the
welding current from the armature cables by a sliding contact to the moving holding
clamp or clamps.
Figure 15 is a view in section of the connections between the exciting armature
coils and the field coils.
Figure 16 is a perspective view of the manner of winding the oxciting coils on the
arniature.
Figure 15 shows a form of commutator that may be used in collecting the exciting
currents of a self exciting direct welding machine.
Figure 17 shows in a partial vertical section one of the clamps.
Figure 18, shows the same clamp in side elevation detached from the machine.
Figure 19, is a perspective view of an eccentric employed for tightening the clamp
as will be hereinafter described.
Figure 20, is a side elevation, and
Figure 21 a plan, of another form of clamping device for the work.
Figures 22 and 221, are details of said clainping device.
Figure 23, is a view in partial vertical section of another form of my direct electric
welding brazing or forging machine.
Figure 24, shows a means of collecting the heavy wolding currents from the collector
rings of the armature.
Figure 25, is a detail showing means of conveying the welding currents, to the base
plate of the welding clamps.
Figure 26, is a detail of the exciting circuit of the armaturo, showing the mannor
of connection with the commutating devices.
Figure 27, is a side view partly in section, showing the windings of the field
magnets and armature; also device for conducting the wolding currents to the
holding clamps; and also means for regulating the exciting circuit of the field
magnets.
Figure 28 illustrates the principle of the device for automatically cutting off the
current when the welding or forging or soldering operation has been completed.
Figures 29, 30 and 31 illustrato devices for automatically cutting off the current.
Figures 32, 33 and 34 illustrate kinds of work to which my invention may be
applied.
In my direct welding machine it is essential to use a dynamo electric generator
which is capable of producing wolding currents of great volume but low electro motive
force between the clamps holding the pieces. A convenient form of such machine

page_text: consists of a revolving field magnet built up of laminated cores bolted firmly together
and copper wire bobbins, producing alternate north and south poles, and an armature
with laminated iron core wound with heavy copper wire bundles or cables. The field
of such a machine can be either separately excited by currents generated in its own
armature and commuted by a suitable commutator placed on the revolving field shaft
of the machine.
Referring to Figure 2, F is a part section view of the field magnet core, being a
part side view of the complete field. The core is fastened by means of lugs and bolts
to a disc or plate N, fixed on the shaft S, S', of the machine, and is made to revolve
by the pulley P.
Figure 3, shows the form of the laminae composing the field magnet core, which
laminne may be made in sections, as shown in Figure 5. When built in this way
the field magnet is held together by a metal core ring, such as is shown at 1, in
Figure 4. While I describe the field magnet core of my direct welding machine to
be built up of laminac, I do not limit myself to this form. The field cores may be
solid but such an arrangement is attended with loss of energy, and is therefore not so
economical as a laminated field core.
Referring to Figure 3, again, the projections P1, P1, P1, are the poles of the field
magnets, over each of which is placed a bobbin wound with copper wire, as win
Figure 7. The form of the carrier or support of the bobbin is shown in Figure 6.
The completed field magnet is shown in Figure 4, the wound bobbin (Figure 7)
being shown in section at ww³ Figure 4. The direction of the winding of the
bobbins is indicated by the arrows in Figure 4. It will be seen that the windings
alternate in direction on the several bobbins i.e., starting at A, which is wound from
left to right, the next bobbin A¹, is wound from right to left, A³, from left to
right, and so on, so that the poles are alternately north and south in one revolution.
Although the winding of the field of the machine described is a series winding, any
other of the windings well known in the art may be used, such for instance, as a
multiple are winding or a winding in series multiple.
The two terminals of the field winding are brought through a hole in the field
magnet shaft and connected with the collector rings C, C₁, as indicated in Figure 13.
The exciting current may be generated by a separate dynamo machine, one pole of
the circuit of which is connected with the brush B', (Figures 1 and 13) resting on the
collector ring C, (Figure 13) which is connected with one end of the field winding,
the other pole of which circuit is connected with the brush B, resting on the collector
ring C, which is connected with the other end of the field winding. The strength of
the magnetic field may be regulated by a variable resistance V (Figure 1) placed in
the field coil circuit where the source of current has a definite electro motive force.
If the exciting field is of constant current the variable resistance should be omitted or
used in shunt to the field coils or to the posts K, of the machine as indicated. Other
well known means of regulating the strength of the field may also be employed.
The armature of my direct welding machine may be made in the following way.
Referring to Figure 2 E, represents a part sectional view of the laminated iron core
of the armature, the lamination being represented by fine vertical lines. These
laminae are bolted firmly together as indicated in the Figure. The form of the
laminated core is shown in end view in Figure 9. There are as many grooves g, g, in
the armature core as there are bobbins in the field. These grooves are wound with
beavy copper conductors or cables, consisting preferably of a number of insulated
copper wires. This windling is represented in Figure 10, and it may be varied as in
Figure 11, where the cables divide, one half the wires forming them going around to
the groove on the left, the other half to the groove on the right as indicated.
The special advantage of winding the armature with conductors or cables consisting
of a number of copper wires insulated from each other, is that the insulation prevents
lateral contact of tlio wires and, therefore, prevents the generation of the intense eddy
currents which would otherwise be produced. In this way considerable waste is
avoided.

page_text: mo 15 mounted upon a sua ise or frame, RS inarcaret.
Mounted upon a frame in direct proximity with the dynamo machine and proferably
constituting a part of the frame or base carrying said machine are the holding clamps
to be used in the welding or forging operations, and with these clamps connection is
made directly from the part of the dynauno generating the heavy electric currents.
By thus combining the clamps and the dynamo machine the use of flexible or
extended connections may be entirely avoideil, and the electrical connection may if
desired he a rigid one. I prefer however to make the connection from the dynamo to
the clamp as follows:-
The armature conductors or cables, leaving the fixed armature are bolted firmly
against the contact plates P P (Figure 1) which convey the welding currents to the
holding clamps H, II.
In figure 1, three separate armature coils such as shown in Figure 10 are supposed
to be employed. Of the six terminals, the three which at any time are of one polarity,
say positive, are connected to one of the plates 1', while the remaining three are
connected to the other plate. By the multiple are connection shown a current of very
large volume is obtained.
By revolving the field, heavy currents of low potential are induced in the armature
conductors c, c, c, which are holted firmly against the contnet plates p, p², Figures 1
and 14, in the manner shown at ", in Figure 2. One of the holding clamps is best
insulated from the table or frame Rus indicatel at 1, in Figure 1. This is to prevent
the passage of the welding current from the contact plate P. to the clamp II', by the
frame R.
A front view of the holding clamps H, H¹, is shown in Figure 1, and an end view
of one of them I, in Figure 2. They are made of heavy pieces of metal so that they
mny conduct the large welding currents to the pieces to be welled and he sufficiently
strong to allow considerable endwise pressure to be brought to bear on the pieces
without danger of their slipping or bending. The clamps should be preferably of a
form which will fit closely the pieces to be welded so as to ensure good contact,
though very small contact will often suffice to carry currents heavy enough to weld
large pieces.
Arrangements can also he made to allow free movement of one or both of the
clamps.
Referring to the drawings in Figure 1, II', is a front view of one of the clamps,
which is bolted firmly to the plate P and is therefore immovable. The other clamp L
is movable, receiving its motion by the device D, d. The har d, is bolted to 11, but
has a free movement about, where it is loosely connected with a pivoted har T,
pivoted at t. A serow spindles, passes through a screw hole in T, after the manner
of a screw viso and is provided at its other end with a ratchet wheel with which a
pawl d', is adapted to engage.
When tho lever A', carrying pawl d', is brought down to a lower position, the
pawl d, (Figure 1) acts to turn the screws, which forces d, (Figure 1,) and the
clamp H, towards H; this motion being rendered possible by the free movements
of d, about j, and T about t, and the sliding contact of H, with the plate p. This
sliding contact is represented in Figure 14, though a plain sliding contact will often
suffice. The clamps H, H³, Figure 1, are tightened about the pieces N, N, by means
of the levers A, A. These lovers are secured to suitable rock shafts 7, mounted in
the base of the clamp and provided with eccentrics 8, as indicated more clearly
in Figures 17, 18 and 19. The eccentrics 8, are embraced by collars 9, formed on
the lower ends of the rods 10, which pass at their upper ends through the top plate 12,
of the clamp and are there provided with the thumb nuts y.
Figure 17 is an end view partly in section of the movable clamp H, showing the
removable piece to, the thumb nuts y, and the lever A. The piece 12, is moved down
tightly upon the piece of metal to be welded by the thumb nuts y, and the lever A, is
brought down tightening the hold of the clamp upon the piece by the eccentrics.
The form of the eccentric is given in Figure 19.

page_text: The welding current is carried to the movable clamp II, Figure 1, by the plate,
which has a sliding contact with H, as represented in end view Figure 2. The plate c¹,
is bolted to the block I, which forms the base of EI, and thus bring the
clamp H, into contact with p, to which half the conductors C, C, C, Figure 1, are
attached.
In order to form a good connection between the plate P, and the plate c¹ one
or the other of the plates P, c', is provided with a gang of contact springs m², as
shown in Figure 14. By these springs good connection is formed while at the
same time permitting the one plate to slide upon the other in the manipulation of the
clamp.
Although the form of machine just described is convenient and efficient, yet
modifications may be made in it to suit varying conditions, and I do not limit myself
in my invention to the particular form described. The form of direct welding
machine just described may be made self exciting by winding a sufficient number
of turns of wire of suitable size in grooves cut in the armature core for that
purpose, and connecting the terminals of these coils with commutator brushes resting
against a suitable commutator placed on the revolving field shaft of the machine,
which suitable commutator is connected with the coils of the field.
In order more clearly to explain this arrangement, I represent an armature wound
with exciting coils, two in each groove, in Figure 16. The grooves 9, 9, as was
explained in describing Figures 8, 10 and 11, are for the cables that carry the
welding currents. The grooves z, z, as will be seen are for the coils that carry the
exciting current.
The exciting coils are wound in the following manner :-Starting with any
groove, z, Figure 16, one turn is made from left to right completely around the
armature and connection made to one plate of the commutator Figure 15; then
taking the next groove on the right a complete turn from left to right is made and
connection taken to the next plate of the commutator, the next groove on the left is
then taken and a complete turn from left to right is made, after which connection is
again made with a commutator plate. The six spacos thus having received one layer
of wire a second layer is applied in the first groove and is made in the direction
opposite to the direction of the first turn and connection made to the fourth plate of
the commutator. The operation is continued in the same manner with the remaining
grooves and the two remaining spaces of the commutator. This winding is sub-
stantially the woll known-Siemen's armature winding.
Figure 15, is a view in sections of the connections between the exciting armaturo
coils, the commutator brushes O, O', and the variable resistance V, which is thrown
in to regulate the strength of the magnetic field.
Figure 15 shows a six part commutator with brushes to be used on a machine with
a six pole field. Of course for every extra pair of coils in the field magnet there must
be two extra segments in the commutator.
In the arrangement above described the exciting coils on the armature are wound
in series, but I do not limit myself to series winding. By using wire of proper size
the exciting coils may be wound in multiple, and by changing the size of the wire to
suit the conditions the coils may be wound in multiple series. Arrangements to suit
these conditions are well known to practical electricians and need not be furthur
dwelt upon here. It is also well known that such coils may be wound in series or on
the core in several different ways, and the same is true of multiple arc winding and of
winding in series multiple.
I will now briefly describe a form of direct machine which may consist of a
stationary field magnet and revolving armature, as above mentioned.
The object of such a form of machine would obviously be to prevent the revolution
of so large a mass as the field magnets around the inner mass of such size as the
armature, and therefore overcome difficulties of friction and heating. The field of
such a machine, may be constructed in the same manner as the field above described,
except that it is bolted firmly to the frame of the apparatus as indicated at 64, 6* in
Figure 23.

page_text: The armature core of the machine, may also be constructed in a similar manner, to
the one above described, but the terminals of the heavy cable winding placed in the
deep grooves of Figure 23, are in this case carried from the armature to collector
rings of large size comparatively, placed on the revolving shaft which carries the
armature, as shown at C, O, in Figure 27, from which continuous rings the current
is taken to the clamps.
The oxciting coils may be wound on the armature and connected to the commutator
in the manner already described.
The currents are collected from those rings by brushes as shown in Figures 24
and 25. Resting on the ring (2, (Figure 2-4,) are any number of brushes 6º, 6º, 6º,
arranged on a frame shown in Figure 25, which frame is pivoted on a bar connected
with the base of contact plate K, K2, on which the holding clamps slide. The
plates K, K², may have springs like plate p, Figures 2 and 14.
Arrangements may be made for throwing on or off the welling current, by
simultaneously lifting or lowering the brushes abovo described. Such arrangement is
shown in Figure 25. The rol or pivot &, carried by contact plates K, K², of the
holling clamps carries the frames M, M', to which are fixed with a constant spring
the brushes 6, 6, 7. One plate M, M, carries the brushes which rest on (2,
(Figure 27,) and the other those which rest on the collector ring (". A handle L,
may be used for raising or lowering the frames around the bar, as a pivot. Any
amount of pressure can be given to the brush resting on the rings, by pressing the
frames down hard.
By revolution of the moving parts of the machine, heavy electric currents of low
potential are induced in the armature conductors, and are carried to the holding
clamps, either as indicated above, or as shown in Figure 1, where the armature
cablus c, c, c, are bolted firmly to the base or contact plates pp².
In both of the arrangements herein described it will be observed that there is au
absence of any commutator for rectifying the currents between the dynamo machine
source and the clamps of the apparatus so that there is no break of continuity in the
path of the heavy electric currents as there would be at the segments or slots of a
rectifying commutator. This is a very important consideration in an apparatus for
this purpose and can otherwise be attained only by the employment of an induction
coil wound so that current of comparatively high tension on one circuit may
generate the heavy or larger volumen currents in a secondary wire which is
directly connected without the intervention of any commutator or collector with the
clamps.
Still other arrangements and modifications may be made in my direct electric
welding machine, and I do not limit myself in my invention to the apparatus
described, but claim broadly the invention of a welding machine which consists of a
suitable dynamo machine for generating electric currents of great volume in combina-
tion with holding clamps and devices for moving and manipulating the same the whole
forming one compact apparatus.
Another form of clamping device is shown in figures 20, 21, and 22. Referring to
Figure 20 M, is the base of the clamp in which is placed a removable picco 12 as
shown. The Ing 20, is fixed to the rear end of this base M, through which a screw
bolt passos having a nut 17, at its upper extremity. The binding frame 18, is pivoted
at an axis 15, as shown in Figure 21, and a lover 9, with an occentric 18, at its
extremity, is attached to a pivot in the manner shown in Figure 20. The levor
eccontric 13, has a free movoinont about an axis, and upon the fruime 18, so that when
the lever arm 9, is brought down, the frame 18, binds tightly upon any picco 5, to be
operated upon, for the roason that the stirrup 6, on which eccentric 13, is pivoted is
hooked to a projecting lug 7, the form of which is shown in Figure 224. Such a
clamping arrangement can be readily adapted to different sizes of piocus by means
either of the irregular projecting lug 7, which can be turned to any position, or by
moans of the screw bolt 10, as shown in Figure 20.
cause the welding or heating current to bo automatically cut off from the work
upon the movement of one of the holding clamps to a predetermined point. The

page_text: machine thus becomes practically automatic in its operation and in welding processes
especially requires no attention beyond placing the pieces in the clamps and switching
on the current. The current may be made to cease to. flow to the work either by
cutting off such current or by cutting off the current which induces it. Thus for
instance the exciting current of the dynamo may be broken instead of the current from
the armature coils which are connected with the clamps.
The principle of this part of my invention is indicated in Figure 28. F³ indicates
the source of current which excites the field of the dynamo or which heats the work.
Y is a base plate which moves with the clamp in the direction of the arrow during the
welding operation. X indicatos a switch which is normally held in position by a
spring S so as to complete the circuit from F. Whon the clamp and support Y move
to a predetermined extent a projection from Y will movo the switch X so as to open the
circuit of F. This directly or indirectly cuts off the current from the article to be
welded. The amount of movement permitted before this takes place will vary under
different conditions.
HH Figure 29 are blocks of conducting material connected with the holding
clamps C, C. The clamp C is however insulated from the base plate or guiding
plate PP by interposed insulation but is firmly bound down thereto by bolts and
thoroughly connected by an electric conductor to H. The bolts themselves may be
made of heavy copper bars passing through the plate P P, and not touching the same.
The clamp is any ordinary arrangement for clamping in position a bar, plate or
wire of metal B of any irregular form.
The clamp is a counterpart of the clamp C except that it slides upon a base
plate P P in suitable guides and is impelled towards C by the spring Z adjustable by
a nut and scrow at N.
The spring Z is insulated so that it doos not make connection between the clamps.
The screw S through the clamp body C is used to hold apart the clamps at any given
distance during the insertion of the picces B B₁ and abutment thereof between
the clamps. The screw $ is of course relieved or turned back when the welding is
done.
An attachment of rod E extending from the movable clamp C carries on it an
adjustable piece A which may be set along the bar in any desired position. This
adjustable piece A on the movement of the clamp spring Z acts to trip a dotont lever D
which when in the position shown in full lines Figure 29 holds the switch arm T in
the position shown in the Figure but which on the movement of the clamp C' towards C
due to the union or welding of the bars S S¹ at their abutted ends, strikes the short
arm of the detent lever D trips it from contact with the switch lever T which lever
impelled by the spring V passes over into the inclined position shown by the dotted
lines in Figure 29. The result of this movement is to rupture or open the circuit of
the exciting current from any suitable generator and thereby cause the generation of
the currents which effect the welding of the bars B B¹ to cease.
Other bars may be set in place and the operation rapidly repeated. The adjustment
of the piece A is such that a certain yielding shall take place before the current is
switched off, as described.
Instead of breaking the circuit of the exciting current at the place of contact of the
detent lever D, and the switch lever T the bar E and adjustable piece A may be
arranged to act as in Figure 30. Here the detent lever simply permits the switch
lever T to be thrown around under the action of a weight or spring V so that the
switch lever will break contact with another contact surface U independent of the
detent lever D. The movement then of the piece A to the left trips that end of the
detent lever D which is in engagement with the switch lever T which switch lever is
then free to move and open contact by swinging on its centre away from the
plate U, Fs, being as before the primary coil.
It is obvious that the welding current might be carried through the switch and
broken in the same way if the switch be made heavy enough.
In Figure 31 I have shown how an electro magnet may be employed to effect the
opening of the primary circuit of F³ instead of a detent iever. The magnet M is put

page_text: into circuit with F and holds, when such circuit is provided with current, its
armature attrateed against the retractile force of a spring V so that the contact
lover T bears upon the fixed surface thereby effecting a circuit through F³, M, U, T,
and around to the source of current.
The adjustable piece A on the bar instead of tripping a lover as in former figures
is attached to one end of the wire of the magnet M while a fixed piece D' is attached
to that part of the circuit leading to the other ond of the wire of the magnet. M.
When the clamp which carries the same, falls into contact with the piece D', if shunts
the magnet M which thereupon releases its armature and allows the contact at TC, to
be opened by the retractile force of the spring V. It is not necessary to state that
the piece 1¹ or contact surface upon which the piece A nets may itself be maile
adjustable instead of effecting the adjustments by means of the piece A, which is as in
former Figures a detent lever switch appliance made to be adjustable in position.
Indeed no adjustment of these parts are necessary if the parts are originally
constructed to hear such a relation to each other and to the work to be accomplished
that the set of the pieces in the clamps will cause the proper relations to exist
between the tripping piece A, the switch actuating piece and the contact or switching
device.
My apparatus may be employed in making rings or other endless shapes or links of a
chain. The link or ring would be made from two bent loops or Ụ shaped portions
such as indicated in Figure 32 united at their free or open ends. The two U shape 1
portions would be placed respectively in the clamps of the apparatus and welded or
brazed by the action of the electric current assisted in the case of welding by pressure.
The Ushaped or other shaped portions united together at their open ends form the
complete link or ring may be each of any desired shape, or made in any desired way.
Compound links or rings made of different metals may be formed in this way.
Thus a link or ring made partly of steel and Gorman silver may be made or in
making a chain, links of steel may be alternated with German silver or other material.
Rings made partly of gold and of platinum may also be constructed.
The apparatus may also be used in joining sections of pipo as indicated in
Figures 3 and 4. Figure 33 illu-trates two sections of pipe which are plain at
their abutting ends and which are united by the electric current and pressure when
the sections are placed in the clamps and current is turned on. In Figure 34 two
sections of pipe united by a sloove are indicated. The sleeve tapors at its ends
outwardly and inwardly and receives the tapered ends of the two sections of pipe to
be united. The sections with the sleeve applied are to be placed in the wolding or
brazing clamps with the joint in position to be heated by the current. If they are to
be united by the welding process moderate pressure is applied. This alone
would form a tight joint between the sections of pipe and the sleeve. I profer besides
however to weld the sleeve or at any rate the thin end portions of the same, to the
sides of the pipe. This can be done by rapid and light hammer blows applied when
the parts have reached the welding temperature. Compression might likewise be
applied.
The apparatus might obviously bo applied also to forming a soldered joint between
the sections of pipe suitable soldering substances boing applied at the surfaces to bo
joined after which the joint being placed between the two clamps of the apparatus may
be brought to the desired temporature by the current Any form of sleeve might be
used as the joint obviously.
Having now particularly described and ascertained the nature of the said invon-
tion and in what manner the same is to be performed as communicated to mo
by my foreign correspondent, I declare that what 1 claim is :—
First. A direct electric welding or forging machine or apparatus consisting of a
dynamo gonerator constructed to gonerato currents of grout volume, and suitable
clamps or holding devices connected with the part of the machine in which the hoavy
currents are genorated said devices being all mounted in a propor frame and in
convenient proximity to one another, as and for the purpose, described.

page_text: Second. In a direct electric welding or forging machine a revolving unipolar field
magnet, in combination with a fixed arinature and conductors wound thereon and
connected to a set of holding and wolding clamps.
Third. In a self exciting direct electric welding or forging machine, an armature
conductor in which currents are induced by the revolution of moving parts, extensions
or connections from said armaturo conductors to a set of holding and welding clamps,
and guides or supports attached to or supported by the frame of the machine bearing
such clamps in combination with a second and distinct armature conductor and
connections therefrom to a variable resistance through a variable reactive coil or its
equivalent, to commutating devices or commutator which commutes the current for
the excitation of the field magnet.
Fourth. In a machine of the kind described, an armature having two sets of
grooves relatively large and small, in one of which is wound the main circuit
conductors, and in the other and smaller grooves, the exciting conductor or
conductors for the field magnets.
Fifth. In a dynamo electric welding or forging machine, a circular laminated field
magnet core made in sections having pole pieces pointing radially inward in combina-
tion with an iron or other metal external ring or casing in which the sections are
borne or carried, substantially as shown and described.
Sixth. In an electric welding or forging apparatus the combination with one of the
clamps, of a ratchet wheel and lever and an intermediate screw connection, as and for
the purpose, described.
Seventh. The combination in an electric welding or forging apparatus with a
movable portion of the clamp, of a rock bar or shaft having an attached operating
handle, one or more excentrics secured to said shaft, and one or more collars or sleeves
embracing said excentrics and connected with a movable portion of the clamp, as and
for the purpose described.
Eighth. In an electric welding apparatus, the combination with a movable clamp,
of a mechanism controlled thereby to cut off the welding current at a predetermined
point, as and for the purpose described.
Ninth. In an electric welding apparatus, the combination of a movable slide, a
clamp mounted thereon, an adjustable stop mounted on said slide, and a idetent
actuated by said stop to open a switch to cut off the welding current at a pre-
determined point, substantially as specified.
Tenth. In an electric welding apparatus, the combination of a fixed clamp, a sliding
piece moving towards and away from said clamp, a clamp mounted on said slide, and
a spring or equivalent device tending to force said clamps together, substantially as
specified.
Eleventh. The herein described method of uniting sections of pipe consisting in
applying a sleeve or collar or coupling tube to the adjoining ends of the sections and
then passing a heavy electric current through the parts to affect a union of the sleeve
and pipe thus completing the joint.
Twelfth. The herein described process of manufacturing links, rings and other
endless shapes of metal consisting in forming two U- or horse-shoe shaped portions,
placing the open or free ends of the same together, and then passing a welding,
soldering or brazing current of electricity across the joint between the two halves or
portions, as and for the purpose described.