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Патент USA US2404620

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July 23, 1946.
J. H. COOPER
2,404,62Q
CONTROL OF FLASH WELDING
Filed ‘ Feb.» 1, 1944
2- SheQ'tsLSheet 1
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JOSEPH H. COOPER
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July 23, 1946. ,
J. H. COOPER
2,404,620
CON‘II‘ROL OF FLASH WELDING
‘ Filed Feb. 1, 1944
2 Sheets-Sheet 2
COOPER
2,404,620
Patented July 23, 1946
UNITED STATES PATENT OFFICE
2,404,620
CONTROL OF FLASHvWELDING
Joseph H. Cooper, Warren, Ohio, assignor to The
Taylor-Win?eld Corporation, Warren, Ohio, a
corporation of Ohio
Application February 1, 1944, vSerial No. 520,582
10 Claims.
(Cl. 219-4)
2
1
This invention relates to electric ?ash welding
and more particularly to methods and devices for
length of the are or ?ash itself.
effecting and controlling during the welding cycle
the condition of the arc either the voltage across
the are or the current ?owing ‘in either thepri
mary Winding or the secondary winding or both
the movement relative to each other of the work
pieces to be joined.
To arrivelat '
reference conditions variable in accordance with
The methods and devices
these windings of the welding transformer em--,
ployed is measured and through suitable relay
mechanisms, preferably of the electronic type, the
ing cycle, it being understood that normally the
relative movement of the work pieces is continu
complete ?ash-butt welding cycle comprises a
?rst period in which the work pieces are brought 10 ously controlled in accordance with variations in
the reference condition or conditions thus ob
together with current passing ‘through them to
preheat the edges, the second or ?ashing period
tained.
A further object of the invention is the provi
during which the edges are spaced apart and an
sion of an improved arrangement for automati
electric are maintained between them, and the
cally controlling the relative movement of the
?nal act of jamming the edges together to upset
work pieces during the ?ashing period of a ?ash
the edges and effect 'a uniform cohesive Weld
butt welding cycle together withan improved ar
throughout the extent of the section. ‘ As the
rangement for shifting the control of .the, rela?
?ashing progresses the metal of the edges is burnt
tive movement of the work pieces from manual
or blown off and it becomes necessary to move
herein disclosed are particularly advantageous in
connection with the ?ashing period of the weld
to automatic operation or vice versa as desired.
the work pieces toward each other to ‘maintain :.
Another object of the. invention is the .provi
the arcing or ?ashing.
sion, in an electric ?ash-butt welding apparatus,
of arr-improved arrangement for manually con.
trolling the relative movement of the work pieces
Heretofore the moving of ‘the work pieces to
ward each other during the ?ashing period has
been accomplished by suitable apparatus under
during the Welding cycle including‘ the ?ashing
period thereof.
either manual control or automatic control of the
type in which the relative movement is regulated
according to a predetermined time-position pat
tern. This latter mode of operation is usually
accomplished by employing a moving. cam for
controlling a hydraulic valve in metering the flow
of hydraulic ?uid to the Work moving means, the
cam'being made up of a multiplicity of separable
segments which can Ice-suitably rearranged to
effect different cam contours’. ‘The manual
method of control requires the constant attention
of a highly skilled operator in-order that the re
quired degree of consistency and uniformity may
be attained in the welding while experience has
shown'that optimum'?ashing action cannot al
ways be obtained by predetermined settings of
A still further object of .the invention is the
provision, in electric ?ash-butt Welding appara
tus, of an improved arrangement for manually
controlling the relative movement ‘of. the work
pieces during the welding cycle including the
?ashing period thereof together with an improved
arrangement for shifting from such manual con
trol to an automatic control at the will .of the
operator.
The above and other objects and advantages
of the invention will be-rmorelfully understood
upon consideration of the following detailed
speci?cation and the accompanying drawings
wherein there isspeci?cally disclosedcertain pre
ferred embodiments of the invention.
In the drawings:
Figure 1 is a schematic representation of elec
tric ?ash welding apparatusconstructed in ac
cordance with‘ the principles of the invention;
the controlling cam in an automatic system.
It is accordingly the primary object of the in»
vention to provide an improved arrangement, in
an electric ?ash welding machine, for controlling
the‘ movement of ‘the work pieces‘ toward each
other during the ?ashing period of the complete
Welding cycle whereby optimum ?ashing condi
tions are automatically maintained irrespective
of the presence of the various factors which ren
.
and
Figure 2 is‘a schematicrepresentation of a
modi?ed part of the apparatusof Figure 1.
The apparatus illustrated includes anormally
der automatic systems heretofore devised. for the 50 fixed platen l8 and a movable platen II of an
purpose Wholly unreliable.‘ In accordance with
electric ?ash Welding machine and, in accord
the present invention, this general object of the
invention is accomplished by controlling the rela
ance with usual practice, ‘these platens are each
arranged to carry electrodes [2 which are opera
tive movement of the Work pieces directly in ac
cordance' with the instantaneous condition 'or
together to the respective platens. whereby the
tive to clamp the two work pieces to bewelded
anoaééo
2;
4
work pieces will have relative movement in ac
cordance with‘ relative movement between the
platens. The electrodes also conduct welding
current to the work pieces and for this purpose
primary winding of the welding transformer I3.
are connected to the terminals of the secondary
winding of the welding transformer 13. The pri
mary winding of welding transformer i3 is ar
in a manner now to be described.
I utilize the instantaneous values of the poten
tials developed across resistances 34 and 35 to
control the operation of the valves 23F and 28B
Deriving energy from the current supply line
CLI is a recti?er 36 the output of which is
smoothed out at 37 to develop a uniform poten
ranged to be connected to a suitable source com
tial across resistor 38, which resistor is provided
prising the line conductors LI and L2 through a
suitable circuit controlling device 14. While this 10 with sliding contacts A and B and connected
across the positive‘ terminal of the resistor 38
device I4 is shown in the drawings, for simplicity
and the contact 13 thereof is a grid-controlled
of illustration, as being simply a switch it will be
space discharge device 39 and a load resistor 48
understood that in actual practice such device
in series. Resistor 34 is in the grid-controlled cir
will ordinarily be of the current modulating type
under either manual or timed automatic control. 15 cuit for tube 39 through contact B, conductor 4|,
resistor 35, and conductor 42 to the control grid
Movable platen ll of the welding machine is
of tube 353. Thus when no current is flowing
arranged to be moved toward and away from the
through the primary of the welding transformer
?xed platen Ml by a hydraulic cylinder 15 under
is tube 39 is held non-conducting by the nega
control of a follow-up valve l5. As such, this
valve has a movable element which is connected 20 tive bias furnished by the resistance 38 from point
B to the negative terminal thereof but upon the
to the movable platen by means of a link El and
appearance of a predetermined opposing poten
a coacting movable element which is moved upon
tial across resistor at as caused by the flow of cur
rent to the primary of transformer l3 the tube
able platen driving means generally may be sim~
ilar to that shown more in detail in the copencling 25 39 begins to conduct to develop across resistor 40
a potential which in a circuit now to be described
application of C. E. Coates, Serial No. 431361;,
rotation of shaft l8. Valve It; as well as the mov
?led February 18, 1942, for “Hydraulic butt welder
contro ,” now Patent No. 2,373,226, dated April 10,
1945. Shaft I8 is coupled with the output shaft
of a direct current motor 19 through a suitable
speed reducing mechanism 2%} and, for a purpose
to be later described, an operating arm 21 is also
keyed to the shaft 18.
Motor i9 is provided with a ?eld Winding 22
which may be connected to any suitable source
of uni-directional current and an armature 23
which rotates in one or the other direction de
is in opposition to the potential appearing be
tween contact A of resistor 38 and the positive
terminal thereof. This latter potential is utilized
to hold the valve 23F normally conducting, the
control circuit for valve 28F being traceable from
the cathode thereof through conductor 43, con
tact A, resistor 40, conductor 44, the secondary
of a biasing transformer 45 to the control grid
of valve 28F. The alternating component fur
nished this circuit by the transformer 45 is ?xed
at a 90° phase angle with respect to the anode
cathode voltage appearing across the valve 281?.
Therefore it will be apparent that valve 28F is
pending on the direction of current flow through
it. Armature current for motor 19 is derived from
a control current supply line CLl through con 40 normally fully conductive tending to rotate motor
19 and the motor connected element of the con
ductor 24, a suitable current controlling device 25,
conductor 25, armature Z3, conductor 2?, dis
trol valve It in a direction to cause movement
the strength of current ?owing in the primary
winding of the welding transformer may be taken
' predetermined potential across resistor 35 the tube
of platen H toward platen Iil.
charge devices 28F and 28R connected in inverse
A control system similar, in general, to the
parallel and conductor 29 back to line CH. The
discharge devices 28F and 28R are preferably of 45 above is provided to control conduction in valve
2BR in response to the instantaneous potential
the grid controlled gaseous type each having a
developed across resistor 35 although the effect is
circuit connected to its control grid for determin
reversed in that a heavier welding current re
ing the point on the respective positive and nega
sults in increased, rather than decreased, con
tive half wave cycles at which conduction in the
respective devices is initiated- In this manner 50 duction in the valve 28R. Thus I provide a recti
her 415 deriving energy from the supply line CLI
the direction and intensity of the current flow
and developing its output, after smoothing out
through the armature 23 of themotor l9 may be
at 41, across a resistor 48 which is provided inter
readily controlled. Thus if, for example, the tube
mediate its terminals with sliding contacts C and
28F is regulated to start conducting earlier on its
D. A controlled space discharge device 49 and a
half Wave than the tube 28R the resultant com
load resistor 50 is connected across the positive
ponent of current will flow through the armature
terminal and the contact D of the resistor 48 and
23 insuch manner as to cause the armature to
the control circuit for tube 49 is traceable from
rotate in a direction to move the platen H to
the cathode thereof through contact D, conductor
ward the platen I3. If the ?ring point of tube
28F is further advanced motor l9 and conse 60 5|, resistor 35, and conductor 52 to the control
grid of tube 49. Again a portion of the potential
quently platen l l is speed up.
across resistor 48 is utilized to hold the tube 49
As explained above, the instantaneous value of
non-conducting and upon the appearance of a
as an indication of the condition of the ?ashing 65 49 begins to conduct to pass current in proportion
to the value of the potential developed across re
during the ?ashing period since if the arc is too
sistor 35. As the tube 49 conducts it develops
short for optimum operation an excessive current
across resistor 50 a potential which, in the circuit
is being drawn While if the arc is lengthened to
now to be described, is in opposition to the po
the point where extinguishment becomes prob
able the current is very materially decreased. 70 tential across that portion of the resistor 49 which
is intermediate the positive terminal thereof and
Therefore I may employ current transformers 3i!
the contact C‘. This last mentioned circuit is the
and 3! the outputs of which are recti?ed at 32
control circuit for valve 28R which is traceable
and 33, respectively to develop across resistances
from the cathode thereof through conductor 53,
34 and 35, respectively, potentials which are pro
portional to the strength of current ?owing in the 75 resistor 50, resistor 48 to contact C, conductor 54,
9,404,626
5
the secondary of a grid biasing transformer‘ 55,
conductor 56 to the control element of valve 28R.
While the alternating component furnished this
circuit by the transformer 55 is displaced by 90°
in phase’ with respect to the anode-cathode volt
6
I may provide an energizing circuit ‘for solenoid
6H which includes a current source GI and a switch
62 which is closed upon the arm 2| reaching a
predetermined advanced position. Since arm 21
is keyed to one of the coasting movable elements
in follow-up valve l6 switch 62 will not be closed
until the desired amount of metal is burned off
ponent applied between the positive terminal and
the edges of the Work pieces which are‘ to be
contact 0 of resistor 128 is sui‘?cient to hold the
joined. It ‘should also be understood that the arm
valve 28 normally non-conducting. However,
when tube 49 begins to conduct the opposing di 10 2| may be employed to open, either directly or
through time delay apparatus, the circuit con
rect potential supplied by resistor 50 will cause
trolling device [4.
valve 28R to conduct current in an amount de
Under certain conditions it may be desirable
termined by the value of the potential developed
to
provide for the regulation of the movement
across resistor 35.
It should now be apparent that upon the work 15 of the movable platen either manually or auto
matically‘ at the will of the operator and in Fig
pieces being clamped by the electrodes 12 and the
ure- 2 I have shown a portion of» the circuit of
closure of the circuit controlling devices 14 and
Figure 1 in’ modi?ed form whereby the machine
25 motor 19 will operate to advance platen H
may be readil-y‘put» on manual or automatic oper
to bring the work pieces together and upon such
ation. Referring to Figure 2, I provide a mul
short-circuiting of the welding transformer very
tiple poled switch or relay structure shown sche
heavy current will be drawn by the primary
matically at- 65 which is operative, when its oper
thereof which condition will be at once sensed
ating elementis moved to the left as viewed in
by the transformers 3B and 3| and the potentials
Figure 2, to connect the outputs of recti?ers 32
consequently appearing across resistor 34 and 35
and 33 across the resistors 3K1 and 35 in the same
will operate to decrease or terminate conduction
manner as in Figure 1 thus providing for wholly
in valve 28F while initiating the increasing con
automatic operation. When the‘ switch 65 is
duction in valve 28R. Depending on the nature
moved to the right the secondaries of transform
and character of the work, the voltages applied,
ers 39- and 3| are connected across the resistors
and other factors, the movable platen II will
age across the valve 28R the negative direct com
either stop or back up slightly but in either case 30 34 and 35-, respectively, through the discharge
devices 66 and 61, respectively, which are prefer
the arcing or flashing between the work pieces will
ably of the grid controlled gaseous type. Con
be initiated and maintained because the balance
duction in tube 66 is controlled by an impulsing
of the system is so adjusted for the particular
transformer 68 the primary of which is connected
work at hand that the interval between the pieces
will be maintained to produce optimum flashing.
It the arc lengthens to the point where it is about
to become extinguished or if it is extinguished the
current in primaries of the transformers 3i] and
3| decreases to such value that valve 28F passes
much more current than valve 28R so that motor
l 9 rotates in a direction to again move the platen
I I toward the platen In. In this manner the work
pieces in the welding machine are automatically
moved relative to each other in such manner that
optimum ?ashing between the pieces is main
tained.
Under certain conditions it may be desirable
to back off the platen ll under manual control
during the time that the switch 25 and the cir
across the supply line Ll, L2 through the resist
ance shown and, similarly conduction in tube
61 is ‘controlled by an impulsing transformer 69,
the primary of which is also connected across the
line Ll, L2 through the resistance shown. In
parallel with the primary of transformer 68 is a
variable reactor having a coil 10‘ which is ?xed
physically with respect to normally stationary
parts of the welding machine and a soft iron
core ll arranged to be moved further into the
coil 10 upon movement of the platen ll toward
the platen 10. As the core 'Il moves toward the
center of the coil 10' the reactance of the coil-10
diminishes thereby bringing the output of the
transformer 63 closer in phase with the anode
cuits are otherwise conditioned for automatic op 50 cathode voltage across tube 66 causing this tube
to conduct more current which is induced in the
eration. For this purpose I may provide a double
secondary of transformer 33 upon the flow of cur
poled switch 51 one contactor of which connects
of valve 28F highly negative thus extinguishing
rent through the primary of transformer I3. In
parallel with the primary of transformer 69 is a
platen at the start of the complete Welding cycle.
For -controlling according to the latter method
transformer primary circuit the magnetizing cur
rent flowing in this circuit furnishes suf?cient
contact B of resistor 38 to lead 44 to drive the grid
this valve. The other contactor of switch 51 55 variable reactor having a ?xed coil 12 and a
soft iron core 13 which is arranged to be moved
connects lead 53 with contact D of ‘resistor 48
toward and away from the center of coil 12 by
through a variable resistance 58 to drive the grid
a manually engageable lever 14 and it will be
of valve 28R highly positive thus conditioning this
understood
that as the lever is moved to the
valve for maximum conduction.
Upon completion of the ?ashing phase of the 60 left, bringing core 13 closer toward the center of
coil 12 the value of the reactance of coil 12 will
welding cycle it is necessary that the work pieces
diminish thereby bringing the output of trans
be rapidly brought into pressure engagement with
former 69 more closely in phase with the anode
each other and for this purpose I may employ a
cathode voltage across tube 61 to increase con
dumping valve 58 also connected to the cylinder
l5 and operative, when its operating solenoid 60 65 duction in this tube. The mechanical linkages
and the parameters of the electrical circuits are’
is energized, to rapidly conduct a large volume of
so adjusted that with the platen ll fully re
hydraulic fluid under pressure to the outer end
moved from the platen Ill and the lever 14 also
of cylinder [5 all in a manner more fully ex
removed to its right position the valves 28F and
plained in the above mentioned co-pending ap
26R conduct equal current so that the armature
plication. The energization of solenoid 69 may
of motor 19 is locked and the mechanical parts
be either time-controlled or controlled in accord
of the machine are at rest. It should be noted
ance with the position attained by the movable
that upon closing of the device M in the welding
platen as related to the initial position of the
2,404,620
7
8
energy for translation through transformers 30
and 3| and tubes 66 and 61 to develop su?icient
potentials across resistors 34 and 35 to effect this
mode of operation, it being understood that re
sitory electrical condition in the work circuit in
control of the relative conduction in said devices
whereby the speed and direction of movement
position of the parts we may assume that the
core 13 is in the center of coil 12 while the core
3. Apparatus according to claim 1 further in
cluding means responsive to the strength of cur
‘H is o? to the right of the center of the coil l O
10. Now if the lever 14 is moved to the left
the reactance of coil 12 is diminished decreasing
the potential across resistor 35 and consequently
decreasing the current being passed by valve
28R. The forward component of the current
rent ?owing through said transformer, control
of said movable control element of said follow
sistors 34 and 35 of Figure 2 are connected into 07 up valve is controlled so as to effect automatically
the current modulating circuits for armature 23
optimum ?ashing between adjacent edges of said
in the manner shown in Figure 1. In the stated
work pieces.
then furnished armature 23 overbalances and
the armature rotates in the proper direction to
move platen II to the left. Upon such move
ment reactance of coil 10 is diminished, the ulti
circuits intermediate said responsive means and
the control elements of said devices, said con
trol circuits being operative upon increase of
transformer current to increase conduction in
one of said devices while decreasing conduction
in the other and vice versa whereby optimum
?ashing between adjacent edges of said work
pieces may be automatically maintained.
mate effect of which is to diminish the current ,
4. Apparatus according to claim 1 further in
cluding means responsive to the value of a tran
sitory electrical condition in the work circuit in
control of the relative conduction in said devices
passed by valve 28F and in this manner a balance
may be maintained whereby the movement of the
platen H follows precisely the movement of the
whereby optimum ?ashing between adjacent
lever 74. By providing switch 65 with an operat
edges of the work pieces may be automatically
ing coil the operator may at any time either be 25 maintained, a manual control lever, means to
fore, during or after the actual welding cycle
establish an electrical condition variable in ac
transfer the control of the movement of the
cordance with changes of position of said lever,
platen II from “manual” to “automatic” or vice
and switching means operative to effect utiliza
versa. For example, it is contemplated that a
tion of either said value or said condition at the
control button for such actuating coil may be
will of the operator to control the relative con
mounted directly on the lever 14 so that at any
duction in said devices.
time upon release of the lever and button the con
5. In electric ?ash-butt welding apparatus
trol will automatically shift to “automatic.”
having means to move the work pieces toward
This is advantageous since in many cases it is
and away from each other as well as means to
desirable to preheat and initiate ?ashing under 35 conduct welding current thereto, the combina
manual control after which automatic control
tion of means to control said means to move
of the ?ashing would normally be more desir
able.
comprising a control element the direction and
speed of movement of which determines the di
While in the embodiments speci?cally described
rection and speed of the relative movement be
above I have taken as the controlling reference
tween said work pieces, a direct current motor
condition the strength of current ?owing in the
for driving said control element, an electric valve
primary winding of the welding transformer it
for controlling the flow of current through the
should be understood that with suitable and obvi
armature in one direction, a second electric valve
ous modi?cation the condition may as well be a
for controlling the ?ow of current through said
measure of the voltage appearing across the work 1, armature in the opposite direction, and means
pieces or a measure of the current ?owing in
to control the conduction in said ?rst valve with
the secondary winding of the welding transform
respect to the conduction in said second valve
er or any combination of these three factors.
whereby the direction and intensity of the cur
The above speci?cally described embodiments
- rent ?owing through said armature is controlled.
of the invention should be considered as illus- .
6. Apparatus according to claim 5 further
characterized in that said means to control the
relative conduction in said valves comprises
means responsive to the value of a transitory
electrical condition in the work circuit whereby
trative only as obviously many changes may be
made therein without departing from the spirit
or scope of the invention.
Reference should
therefore be had to the appended claims in de
termining the scope of the invention.
optimum ?ashing between adjacent edges of
said Work .pieces may be automatically main
What I claim is:
tained.
1. In electric-?ash-butt welding apparatus
'7. Apparatus according to claim 5 further
having a welding power transformer, a normally
?xed platen and a movable platen adapted to
characterized in that said valves are of the con
hold work pieces, a hydraulic cylinder to move 60 trolled gaseous type connected in inverse par
said movable platen, and a follow-up valve in
allel in a current supply circuit interconnecting
control of the flow of ?uid under pressure to
an alternating current source and said arma
opposite ends of said cylinder; the combination
ture, said means to control the relative conduc
of means to move a movable control element of
tion in said valves comprising means applying
said follow-up valve comprising a direct cur
rent motor, and means to energize the arma
alternating grid potentials to the control ele
ments of said valves, and means applying con
ture of said motor in alternate directions and
trolled direct current potential components to
with controlled intensity comprising a source of
the control elements of said valves.
alternating current and a circuit interconnect
8. Apparatus according to claim 5 further
ing said source and armature, said circuit in 70 characterized in that said valves are of the con
cluding in series therein a pair of controlled elec
trolled gaseous type connected in inverse par
tric discharge devices connected in inverse par
allel in a current supply circuit interconnecting
allel relation.
' 2. Apparatus according to claim 1 further in
cluding means responsive to the value of a tran
an alternating current source and said arma
ture, said means to control the relative conduc
75 tion in said valves comprising means applying
,
2,404,620
9
alternating grid potentials to the control ele
ments of said valves, and means applying con
trolled direct current potential components to
the control elements of said valves, the values of
said direct current components of biasing po
tentials being variable in accordance with the
value of a transitory electrical condition in the
work circuit whereby optimum flashing between
adjacent edges of said Work pieces may be au
tomatically maintained.
9. In electric ?ash-butt welding apparatus
10
establishing an electrical condition variable in
accordance with variations in the interval be
tween said work pieces, a manually engageable
element, and means to control the energization
of the other of said devices comprising means
establishing an electrical condition variable in
accordance with variations in the position of
said element.
10. Apparatus according to claim 9 further
characterized in that said ?rst and second men
tioned electrical devices each comprises a con
trolled gaseous discharge device connected in
having means to retain the work pieces to be
inverse parallel for controlling the ?ow of cur
joined and to conduct current thereto as well
rent from an alternating current source, said
as means to move said pieces toward and away
from each other, the combination of an electri 15 ?rst and second mentioned means to control
comprising means to condition said devices for
cal device in control of said means to move
conduction at variable points during the re
operative when energized to effect a force tend
spective half cycles of anode-cathode voltage
ing to move said pieces away from each other, a
applied across the respective devices by said
second electrical device operative when ener
source.
gized to effect a force tending to move said pieces
toward each other, means to control the energi
zation of one of said devices comprising means
JOSEPH H. COOPER.
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