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Патент USA US2378741

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June 19, 1945.
2,378,741
w. AJWEIGHTMAN
METHOD OF SPOT WELDING
Original Filed Aug. 25, 1959
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Original Filed Aug. 25, 1939
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METHOD OF SPOT WELDING
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INVENTOR
William \FLWeightman.
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ATTORNEY
June 19, 1945.
w. A. WEIGHTMAN
2,378,741
METHOD OF SPOT WELDING
Original Filed Aug. 25, 1939
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J1me 19, 1945-
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.METHOD OF SPOT WELDING
Original Filed Aug. '25; 1959
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' Original Filed Aug. 25, 1959
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June 19, 1945-
w. A. WEIGHTMAN
2,378,741 ‘
METIjOD OF SPOT WELDING
' Original Filed Aug. 25, 1939
' 11 Sheets-Sheet 6
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INVENTOR
W'LLL‘Lam Aweiqh’cmclnk
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ATTORNEY
June 19, 1945.
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w. A. WEIGHTMAN
METHOD OF SPOT WELDING‘
Original Filed Aug. 25, 1939
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William QWeighfman.
BY 9‘ {'71 ATTORNEY’
June 19, 1945.
w. A. WEI'GHTMAN '
2,378,741
METHOD OF SPOIT WELDING
Original Filed Aug. 25, ‘1959
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INVENTOR
William AWeigh’cmcm.
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ATTORNEY
‘Julie 19,1945
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A. WEIGHTMAN
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METHOD OF SPOT WELDING
I Original Filed Aug. 25, 1939
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Original Filed Aug. 25, 1939
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METHOD OF SPOT WELDING
Original Filed Aug. 25, 1939
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Fatentecl June 19, 1945
231,741
UNITED STATES PATENT orncs
2,378,741
METHOD OF SPOT-WELDING
William A. Welghtman, Philadelphia, Pa., ss
signor to Edward G. Budd Manufacturing Com
pany, Phlladelphia,_Pa., a corporation of Penn
sylvania
Original application August 25, 1939, Serial No.
291,838. Divided and this application June 18,
1942, Serial No. 447,495
3 Claims. (01. 219-10)
The invention relates to a method of and a
causes considerable crowding of the welding tools
and results in increased spacing between welds.
Considering these factors, the curvature of the
beam, the requirement that the curvature of the
beam he changed from time to time, and desir
system for spot welding which is especially adapt
ed for structures ‘having a number of closely
spaced welds.
The invention relates more speci?cally to the
production of heavy sheet metal beams, for ex
ample of box section, wherein the parts are se
cured by a plurality of spot welds~substantially
uniformly spaced along the length of the beam,
and particularly to apparatus therefor.
The invention is an improvement over the ap
paratus and procedure described ‘and disclosed in
the copending application Serial No. 143,60i), ?led
May 19, 1937, which has now eventuated into
Patent No. 2,229,993, dated January 28, 1941.
The apparatus forming the subject matter of
ability of increased welding pressures, it is an ob- '
ject of the present invention to provide a method
of. and system for effecting a line of closely spaced -
spot welds, which method or system may be
?exible inthat it can be changed without great
difficulty to accommodate changes in curvature, in
the line.
‘
An object of, the invention is to provide a
method and system which may readily accom
15 modate and effect welds in various thicknesses‘ of
metal up to and including those thicknesses re
the aforementioned application comprises a ma
v quiring high welding tip pressures. ‘
chine ter the rapid production of frame members
Another object of the'invention is to provide
composed of a ?anged channel member and a
a method and a system especially adapted for
cover plate, the two being secured together by 20 the formation of a plurality of spot welds close
a plurality of closely spaced spot welds between
ly spaced on a curved member where the axis of
the ?anges and the cover plate along the length
the spot welds is normal to the curvature.
’
thereof. The frame member forming the par
A still further object of the invention is to pro
ticular subject matter of the disclosure is adapt
vide a method and system entailing equipment
ed for use in automotive vehicle frames and, as 25 having great accessibility'for adjustment, re
will be well understood in the ‘art, such frame
placement of parts liable to wear as well as for
members are not necessarily straight and from
loading and unloading.
time to time are designed with various curva
Still another object of the invention is to pro
tures to accommodate various elements or" an
vide- a. method and system or equipment ,for
automotive vehicle‘ which support the frame or 30 effecting a plurality oi.‘ closely spaced welds upon
which the frame supports. ‘With the acceptance
a reversely curved workpiece normal to the cur
of such frame members for use in the automotive
vature thereof, which comprises a plurality of
field as above described, increased thickness of
stages or coordinated machines for e?ecting welds
the members forming a part thereof has been
found desirable for use in heavier vehicles re
quiring the use of heavier welding pressures than '
were heretofore capable'of being obtained upon
an apparatus such as disclosed in the aioremen-l
tioned application. Since the motive power for
obtaining the welding pressure is derived from
iiuid pressure through the use of cylinders and
pistons, either an increase in pressure ‘of the
fluid would be necessary to increase the welding
pressure, or else an increase in cylinder diam
eter would he required. The extent to which 45
pressure may he increased may ‘be limited by
at a greater spacing in each stage but suhstam '
tially intermediate the welds of the other stages.
The above and other novel features of the in
vention will appear more fully hereinafter irom .
the following detailed description when taken in
connection with. the accompanying drawings. It
is expressly understood, however, that the draw
ings are employed for purposes of illustration only
and are not designed as a de?nitionof the lim
its of the invention, reference being had for this
purpose to the appended claims.
in the drawings wherein similar reference char
acters refer to similar parts throughout the sev-'
various mechanical considerations. The increase
eral views:
I
in the diameter of cylinders where a plurality
Figure 1 is a side elevation of a part of the
are closely spaced to effect a plurality of welds
results in an increase in spacing of those welds. 50 vapparatus termed a press welder and iscillus
- trated in pressed welding position.
Further, where the curvature of the member-in
Figure 2 is a longitudinal section through the
which welds are to be e?ected is considerable
press welder of Figure 1 substantially through‘
and the welds are made with the axis normal
to the curvatures, the presence of welding tools
the. center thereot,-the press welder being shown
,
.
‘
or cylinders radially inward of the curvature 58 in separated position.
2 _
2,378,741
channel member 32, asvillustrated more in detail
in Figures 3, 4 and 5. The support members
are secured in their various positions by a plate
Figure 3 is a section taken on the line 3-3 of
Figure 2 showing the detail of the press ram.
Figure 4
of Figure 1
Figure 5
of Figure 1
Figure 6
is a section taken on the line 4--4
showing the detail of the press ram.
is a section taken on the line 5-5
showing the detail of the press ram.
is a section taken on the line 6-6
of Figure 1 showing the detail of the table and
the support for the welding guns.
Figure 7 is an enlarged fragmental end ele
62 lying on the base member 52 and tie members
64 extending in between adjacent support mem
bers 5B. The U-shaped openings are provided
with hardened angular cheeks 86 for supporting
the channel member adjacent the ?anges there
of and the space between the cheeks is so ar
ranged as to closely fit and engage the channel
member workpiece. The workpiece is located lon
vation of the apparatus of Figure 1 illustrating
gitudinally by a hardened abutment 81 located
in detail the operating cam mechanism.
upon the side member 34 of the frame of the ma
Figure 8 is a section taken on the line 8-8 of
chine as illustrated in Figure 2.
Figure 7.
a
As illustrated in Figure 2 the press ram 40 is
15
Figure 9 is an end elevation of Figure 7.
‘
composed of a main portion having dies 68 and ‘I0
Figure 10 is a diagrammatic illustration show‘
rigidly secured thereto and a central vertically
ing the arrangement of the welding guns upon
sliding portion 12 having a die ‘I4. To facilitate
a workpiece and the position of the ‘welds to be
loading of the machine the central die 14 is pro
effected thereon at different stages.
Figure 11 illustrates diagrammatically a series 20 vided with two pairs of spring pressed latches 16
which are adapted to catch and hold a cap strip
of stages for effecting a complete set of welds as
against the die prior to operation of the press
illustrated in Figure 10.
ram. To assure proper location of the cap strip
Figure 12 is a top plan view of a re-welder
with reference to this die, the cap strip is pro
adapted for use in any one of the second, third or
vided with a’pair of holes which in loading upon
fourth stages of Figure 11.
25 the die 'H-must be aligned with pins 18 carried
Figure 13 is a side elevation of the re-welder
by the die. In loading it will readily appear that
of Figure 12.
the cam surfaces 80 of the latch members 16 are
Figure 14 is another side elevation of Figure
12 illustrating the cam operating mechanism.
Figure 15 is a section taken through the re
30
welder of Figures 12, 13 and 14 showing the same
in loading position.
so contoured as to readily cause the latches to
open to receive the cap strip as the cap strip is
pressed toward engagement with the central die.
The central slidable portion of the ram is carried
.
in the main portion of the’ ram on guides 82, I2
and its movement is limited by a transverse bar
Figure 16 is a similar section as Figure 15 show
ing the apparatus in loaded position ready for
84 extending through the main ram portion and
welding.
35 through a slot 85 in the central slidable ram por
Figure 17 is an enlarged section taken on the
tion. When the press ram is lowered, it will,
line l1—l1 of Figure 13 illustrating the detail of
therefore, appear that the central portion of the
the table supporting the welding electrodes.
ram engages the cap strip with the channel mem
Figure 18 is a section taken on the line l8--l8
of Figure 13 showing further details of the mecha 40 ber first and thereafter the remainder of the ram.
and its dies 68 and 10 forms the cap strip 30
nism of ‘Figure 1'7.
upon the extremities of the channel member 22.
Figure 19 is a section taken on the line I9-l9
When the ram is moved to full pressure position as
of Figure 12, and illustrating in detail the talble
is illustrated in Figure 1, the central portion of
moving mechanism.
the ram ?rst takes the position shown in Figure 4
45
Figure 20 is a section taken on the line 20-20
while the main portion of the ram is still in the
of Figure 12 showing the arrangement and de
position shown in the dotted lines. Further lower
tail of the welding guns, transformers and weld
, ing of the ram brings the remainder or main
ing current connections,
portion of the ram to the position shown in Fig
> Figures 21 and 22 are wiring diagrams of the
control circuit.
Referring to the drawings and more particu
ure 4 and, as is also shown in Figure 5. The dies
50 ‘l4, ‘l0 and 68 are thus brought into alignment to
larly Figures 1 and 2 thereof, there will be seen a _
press weldingimachine adapted to secure a cover
plate or cap strip 30 on a ?anged channel mem
form the cap strip around the channel member
and to hold the same in such position while a
number of spot welds are effected. In order that
sufficient clearance for the pairs of welding elec
ber 32, the sectional details of which will readily 55 trodes be left, the cheek portions 66 are arranged
appear in Figures 3, 4 and 5. The machine is
in between the welding electrodes and are adapted
composed of a frame-work having uprights 34. and
36 and a transverse top member 38. Slidably po
sitioned between the uprights 34 and 35 and un
to align with similar'hardened spaced blocks 89
arranged along the length and lower face of the
dies 68, ‘I0 and ‘I4. Alignment of the dies 14, ‘ll
derneath the top member 38 is a press ram ‘4|! 60
and
68 is ‘assured by the engagement of the cross
adapted to slide on ways 42 and 44 and adapted to
bar 84 with the lower limit 81 of the slot .6 in
be lifted and lowered by a cylinder 46 in the top
the central slidable portion of the ram. When the
member and a piston 48 on the rod 50 connected
ram is in lowered or press position, it will be ob
to the press ram.
served in Figure 4 that the latch members 18 are
In order that considerable pressure in addition 65 opened by reason of their engagement with the
to the weight of the press ram may be applied
flanges 33 of the channel member 32, the latches
to the workpieces, the top member is held to a.
[being so arranged upon the die 14 as to not reach
base member 52 through heavtr tie rods 54 and
beyond the channel flange. Thus, when the press
56 extending through the uprights as is illustrated
ram is raised, the latches ride over the cap strip
70
in Figures 1 and 2.
.
leaving the channel and cap Strip in the slots 60
For the purpose of supporting the channel
of the support plates 5!.
member 32 in the bottom portion of the machine
Referring to Figure 6 wherein a transverse en
there is provided on the base member a plurality
larged section through the lower portion of the
of support members 58, each having a U-shaped
machine is illustrated, there will appear a pair
notch 60 in the end thereof adapted to receive the 75
_
aeva'mi
of welding guns 90 and 92 with their welding
electrodes arranged in position for effecting a
weld between the ?ange 33 of the channel mem
ber 32 and the cap strip 30. It will appear that
the welding electrodes so positioned would inter
fere with the loading of the'channel memberv 62
in its support as well as the lowering of the
3
table. For this purpose each piston» rod is pro
vided with a rack I80 which is adapted to en
gage and mesh with a pinion I82 carried on a
shaftI84 which extends along the length of the
_ machine to a similar pinion-and rack associated
'with the other cylinder. As shown in Figure 2, ~
to accommodate such a mechanism for both pairs
ram 60 carrying the cap strip 30'thereon. To
of cylinders and both tables, a concentric tubu
overcome this interference, the welding guns 90
and 92 are supported on laterally movable tables 10 lar shaft I86 is provided around the shaft I84 and
carries thereon at either end pinions I88 and I89
911 and 96 so that upon loading and unloading
of the machine the welding guns can be moved
laterally out of the way of the workpiece. As is
shown in Figure 1, the table 96 carries a series‘
adapted to engage and mesh with racks associated
with the pistons of the cylinders adapted for op
erating__ the other table.
On each table, as has previously been described,
table through a series of shaped support blocks 15 are arranged blocks 98, I00 and I02 having an
upper contour I06 corresponding to some extent
98, I00 and I02, each 0f_WhiCh support blocks
with the shape of the frame member or workpiece
have a flat bottom face I04 for engaging. the table
and welding guns are secured to these blocks in
and a contoured upper face I06 for securing the
proper position for effecting the necessary welds.
welding guns thereto in a proper position for
20
Also
carried on each table are a pair of bus bars
operation upon the varying curvature of the
I90 and I92 supported on brackets I94, which bus
channel and cap strip workpiece members. All
, of welding guns 90 which are secured to the
the welding guns on the one side of the machine‘
are, therefore, carried upon one of the table
vmembers 9d and 96 and those on the other side
the machine are carried on theother.
,
‘To support the tables for lateral movement
plurality of spaced rollers and guide members
are provided as at I06. Each consists of top
bars are connected to stationary transformer
leads I95 and #96 through flexible conductors I98.
Since the welding guns themselves, 90 and 92,
are of the ?oating variety as willhereinafter be
described, they are connected to the bus bars.
590 and I92 through ?exible conductors 200 and
202.- The bus bars I90 and I92 are arranged in
four different sections along the length of the
bottom grooved guide rails H0 and II2,
is; ch, as is shown in Figure 18, are held to 30 machine and for each section a transformer is
provided. ‘The arrangement of the transformers
gether centrally by a block II 4 which separates
g
of the guide rails in two parts.
Rollers
carried
in brackets IIB secured to the tables‘
i353 and 96 are adapted to run upon the rails. H0
in the frame is-shown in Figures 1, 2 and 6
particularly and are indicated by the reference
character 204.
I
l 32, the spacing in the rails being such that 35 Associated with each- section of bus bar is a
group of welding guns six in number which are
only sufficient clearance is provided to prevent
adapted to enjage the work and effect a. weld in
a roller from contacting both rails at the same
‘rapid succession. During the engagementof the
time.
work by one gun the remaining five guns are out
The detailed construction of the block and
’ guides may be gathered from Figures 17 and i8 40 of engagement with the work‘so that upon en
ergizing the welding transformer for that par
hereinafter referred to more in detail wherein
_ similarrollers and guides are provided in re- - ' ticular group and the bus bars, welding current
will ?ow to only the one gun in engagement with
verse arrangement.
the
work. The apparatus in practiceis adapted
To move the tables laterally into and out of‘ 45
to effect a weld in the interval of one second and
operative position fluid pressure cylinders ar- .
each gun, assuming a sixty cycle alternating cur
ranged in the base and acting on levers ‘are em
rent is employed-is adapted to engage the work
ployed. In Figure 6 this mechanism is illustrated
in ten cycles, to be energized with a Welding cur-g
some detail ‘and there is shown there a cylin
rent‘ for a period of ?fteen to twenty ‘cycles, dur-.
ltil having a piston I22 and piston rod M4,
the latter being slidably supported in a guide 50 ing which period the bus bars are energized from
‘The piston rod is connected to lever I30 .
the welding transformer, and thereafter the weld
ing electrodes dwell'in their position under pres
through‘ a pair of links I32 pivoted to the piston
sure for approximately ?fteen cycles fbefore part
rod it’; at £134 and to the lever I30 at I36.-_ The
ing from the work.
'
e
levers are fulcrumed at I38 in journals I40 com
(To
effect
this
operation
2.
Geneva
and cam op-V
55
paced of spaced plates I42 and I46 adapted to be
erated valve mechanism is provided to supply
secured to the vertical transverse frame members
the welding guns with air pressure for causing
i and his. The spaced plates'I42 and I46'have
the electrodes to engage the work and separate
integral journal bosses M2 and I56 for receiving
therefrom. For this purpose an electric motor
pivot
I58 of the lever. Each ‘lever is
2I0 is provided in conjunction with a gear box
campus
of spaced plates I60 and I62 secured 60
2I2 having a, timer shaft 2I4 driving through
together by a web E84 and the upper ends ‘of
. a Geneva movement, a valve operating shaft 2I6.
the lever are connected to the tables 94 and 96
through an adjustable link I10 pivoted to the
lever en. plus W2 and to the-'table through a
This valve operating shaft 2I6 extends through
the length of the machine and drives through
trunnion l'l?l and depending table’bracket I16. 65 gears 220 and 222, (see Fig. 7) and bevel gears
224 and 226 pairs of cam shafts 228, 230, 232
The adjustable link ll0'is provided with adjust
and. 232 located on each end of the machine, a
mentnuts its and H9 between which the trun
total of four cam shafts in number. The speed
nion block‘ Ills! is adjustably clamped so that the
table adjustment is'facilitated. _ To move each
table a cylinder is preferably employed at each
end as is illustrated iii-Figures 1 and 2 and in
order to assure lateral move ent of the table,
means are provided for synchronizing the move
of the motor 2I0 and the Geneva movement is
70 such as to drive the cam shafts 228-234 at the
rate of one revolution in ten seconds and in ten
separate equal steps. The Geneva movement is
such as to‘ drive the cam shafts 228-234 one
ment of the‘ two cylinders associated with each 75 tenth of a. revolution at a. time in the space of‘
9. quarter of a second and the shafts remain idle
4
2,878,741
236 by a spring return 268. Each valve is pro
vided with its individual exhaust 262 and is con
during the intervening three-quarters of a sec
ond period. The timer shaft 2“, Fig. 6, carries
nected to its associated pair of welding electrodes
through pipes 264 and 266 which connect to the
pairs of cylinders as will be hereinafter described
more iii detail in connection with the structure
a cam 218 which is, adapted to operate through
a welding timer, control switch 2i9 to effect the
energization of all the welding transformers 284
at the same time. The Geneva movement which
drives the shaft H6 and the cam shafts 228 to
234 may be of any preferred form, one example
of which is illustrated in the copending applica
tion hereina'bove referred to.
of the welding guns.
It will appear from the above that six-tenths
of the revolution of each cam shaft is employed
10 for operating the various valves and welding guns
leaving four-tenths of the revolution for control
Each of the cam shafts 228 to 234 is provided
with six valve operating cams 236 spaced along
the length of the shaft and with the cams ar
ranged at angles of 36 degrees from one another,
and when each shaft is in a rest position as re
function. For this purpose the cam shaft 228 is
extended'beyond the bearing 242 as is illustrated
at 268 and is provided with a pair of cams 218
and 212 which are adapted to automatically con
trol the operation of the machine subsequent to
sults from the stationary interval provided by
' the formation of all the welds. The earn 218 for
the Geneva movement, a cam engages one of the
valve followers 238 to effect engagement of a
example actuates a switch 214 through the cam
follower 216, which switch interrupts the motor
welding gun and its electrodes with the work.
driving the Geneva movement and valve operat
20
For each pair of welding guns on opposite sides
ing cam shafts. Also upon interrupting the mo
of the workpiece a single valve is provided and
tor circuit the brake 2“ is applied. The cam
thus since there are six pairs of welding guns
212 acts prior to cam 218, and through a follower
in each section, six valves and six cams are re
218 operates a valve 288 to automatically cause
quired to operate the guns of any one section.
the movable tables and the ram to open up the
For this reason the cam shafts 228-234 are four 25 machine for removal of the workpiece after all
in number so as to provide a separate cam shaft
welds have been completed.
for controlling the guns of the four sections.
Referring to Figures '1. 8 and 9, it will appear
that the cam shafts 228 and 238 are geared to
gether as at 24!, and are supported from the up
For an understanding of the control exercised
by the valve 288 over the operation of the ma
30 chine, the control mechanism will now be de
rights 34 and 36 of the main frame of the ma
chine and journaled in bearings 242, one carried
upon a combined air manifold and bracket mem
ber 244, supported on a channel member 246
directly secured to the uprights and the other be
ing located in the gear box housing 243. Also
scribed. As has previously been set forth, the
ram operating cylinder and piston are operated
by fluid pressure derived from a pump 282 which
delivers preferably oil under pressure through a
check valve 284 to a control valve 286. The con
trol valve is adapted to connect the source of
fluid pressure to either the top or the bottom of
carried upon the air manifold and bracket mem
the cylinder through pipe lines 288 and 288, re
bers 244 are the valves 248 which, as is illustrated
spectively, and at the same time connect the pipe
in Figure 7, are adapted to be secured upon the
line 288 or 288, respectively, to the discharge
40
face 248 of the bracket 244 and each valve is
pipe line 292 which is connected to the reservoirs
adapted to cover and connect with ports 258
294 and from which reservoirs the pump 282 re
appearing in the face 248 and connecting with
ceives its ?uid through pipes 296.
a longitudinal bore 252 extending through the
To actuate the ram through the cylinder and
bracket 244, the ports 258 and the bore 252 con
piston 46 and 48, a manual lever 288 is provided
stituting a manifold for supplying compressed
in an accessible position upon the frame upright
air to the valves 248. The manifolds are con
36, which lever is connected to the valve 288
nected to a compressed air line through pipes
through links 388 and 382 and bell crank 884.
254 as is illustrated in Figure 7.
Thus by manual? operating the valve 288 to the
In order to provide the rapid engagement of the
position shown in full lines, ?uid pressure will
welding electrodes with the work as well as rapid 50 flow from the pump into the top of the cylinder
separation therefrom after welding, each welding
gun is provided with a double acting cylinder and
piston, and each valve 248 is adapted when actu
ated by its associated cam 236 to admit compressed
air into the associated pair of welding gun cylin
ders to effect engagement of the welding electrodes
with the work and at the same time to connect
46 forcing the piston 48 downward and discharg
ing the fluid from the bottom of the cylinder
through the valve 286 into the reservoirs 284.
By employing a suitable restriction in line 288
I the rate at which the ram lowers may be regu
lated andafter being lowered into position con
siderable pressure may be applied thereto by the
the opposite end of the cylinder to exhaust. Ad
pressure of the fluid in the cylinder on the top
ditionally, each valve when not actuated by its
side of the piston 48. When the ram is lifted by
60
associated cam 236 is adapted to supply the op
actuation of the valve 286 to a position to the left
posite end of the cylinder with compressed air to
of that shown, fluid pressure is admitted to the
effect immediate separation of the electrodes and
lower side of the piston 48 and the ram thereby
at the same time to connect the other end of the
raised. If the valve is left in this position, the
cylinder to exhaust. Any suitable valve may be
65 ram is prevented from lowering by reason of the
provided for this purpose as will be well under
stood in the art and the details thereof are not
illustrated for they form no part by themselves
of the present invention. In the form of valve
shown as will appear in Figure 8 at 248, the rocker
shaft or cam follower 238 is adapted» to actuate
the valve operating pins 256 and 258 to effect
the functioning of the valve as has hereinabove
been described and the cam follower is caused to
maintain its engagement with its associated cam
check valve 284 which prevents liquid from es
caping from vthe lower part of the cylinder
through the valve 286 through the pump 282
which might, for some reason, be stopped and
70 otherwise in the absence of the check valve 284
permit leakage of the fluid back into the reser
voir 294 and allow the ram to drop.
As the ram lowers, it is desirable to e?ect'lat
eral movement of the tables 94 and 88 as the
75 ram completes its downward movement, and for
‘
2,878,741
this purpose a toggle cam 366 is provided on the
ram as illustrated in Figure 1 and which cam is
adapted to actuate a valve 308 carried upon the
guide 44 on the upright 36. The valve 308 is con
nected to a valve operating cylinder 309 for the
manually operable valve 3l0, whichclatter valve is
adapted to distribute air'pressure to either end
of thetable, moving cylinders I20 to effect lat
5
sure at the guns to assure substantial and uni
form welds, the size of each welding gun is so
great as to preclude the arrangement of sufficient
welding guns upon a single machine to affect all
the welds at one time. Referring to Figure 10 in
which this di?iculty is illustrated, there will ap
pear three welding guns 96 having substantially
the spacing required in mounting the same upon
the movable tables 38 and 98. In order to obtain
the ‘other. Thus, upon operation of the valve 10 welds
as closely spaced as an inch or an inch and
368, the valve 3l0 is actuated to supply ?uid
three-eighths
and to obtain su?icient pressure as
pressure to the inner ends of the cylinders I20
has been heretofore set forth, the welding guns
through the pipe line 3l2, thereby effecting
must have a distance between centers of roughly
movement of the tables toward one another and
from
four to ?ve and one-half inches and, as
positioning the guns 90 and 92 in proper rela
shown in Figure 10, with such a spacing, the
tion to the workpiece to be welded.
'
width of an individual gun may be approximately
As the table 94 moves to its inner limit, the
two and three-fourths or three inches and thus
cam operated switch 32I is closed (see Fig. 6)
the guns may have su?icient clearance between
to start the motor 2H1, and the valve operating
eral movement of the tables in one direction or
'one another so as not to interfere with one an
20 other where it is necessary to arrange the guns
for operation in conjunction with a curved por
'tion of the channel member such as indicated by
the reference numeral 336 in Figure 1. Thus to
closure, all welding current is cut o? and when
effect the full ~number of welds upon a given
theram lifts, such switch is again opened, there 25 member
where the spacing between welds is less
cam shaft.
2
Also as the ram approaches its lower limit the
switch 3!!! (see Fig. 1) is actuated, to close the
circuit to the welding timer, and without which.
by cutting o?'all welding current from the timer.
Upon completion of the welds to be effected as
has been described in conjunction with the cam
shafts illustrated in ‘Figure 7, the valve 280 is op
than that permissible by the welding guns, re
welders are employed to effect the remaining
intermediate welds. For example, in Figure 10
the welding guns 9!) may be three adjacent guns
erated by the cam 212 on the extension 268 on 30 such as are arranged upon the press welder of
the cam shaft 228. Through a second valve op
Figure 1 and theguns are adapted to effect welds
erating cylinder
3“ associated with the manualv
> operable valve 3M and connected to valve 280
332, 334, 336, etc., and, the welds upon the oppo
site side of the channel member, 333, 335, etc.,
' through pipe 3l5, the valve 3"! is actuated to its
are effected by similar guns which are arranged
other position to cause ?uid pressure to ?ow to 35 in pairs upon the other side of the channel as has
the outer ends of the table operating- cylinders
been clearly illustrated and described in conjunc
I20 through the pipe line 3| 3, thus causing the
tion
with Figure 6. The intermediate welds such
tables to separate and clear the workpiece. To
as 338, 340, etc., may be effected in the second
effect simultaneous lifting of the ram with the
stage of welding in a re-welder and the other
spreading of the tables. 94 and 96, a‘ cylinder and 40 intermediate welds 342, 346, 348, etc., may be
piston 3“ is provided in conjunction with the
effected in a third stage in a second re-welder and
manually operable lever 298 to automatically ef- '
the welds 350, 352, etc., maybe effected in a
feet shifting of the valve 286 which controls the
fourth stage‘ and a third re-welder. It will be
ram lifting and lowering cylinder 46 and the con
understood'that the welds upon the opposite side
trol cylinder 3“ is connected with the valve 288 45 of the channel member may be formed at the
through the pipe line 3H for operationsimul
same time by pairing the guns as has been de
taneous with the valve 3 I 0.
scribed in conjunction with the press welder and
In order to remove theworkpiece from the ma
I as particularly shown in Figure 6. In Figure 11
chine upon the raising of the ram, there is pro
there has been diagrammatically illustrated a
vided a pair of upright ejecting cylinders 320
suitable arrangement for a press welder and re
carried in the base of the frame of the machine,
welders for effecting all the welds in four stages.
which cylinders have piston driven ejecting pins
Referring to Figure 11, the press welder is illus
an adapted to reciprocate through guides 324 ‘
in the workpiece Support structure and engage
the workpiece to lift the same out of the U
shaped supporting members 58. Since the U
trated at 354 and the ?rst stage of re-welding is
illustrated at 356 and the second and third stages
illustrated at 358 and 360, respectively. It will be
observed from Figure 11 that the channelmem
shaped supporting members are adapted to form the channel member to ,the correct box section 0
ber may have a lateral bend as illustrated at 362
as well as vertical curvature as has been referred
‘to in conjunction with the press welder herein- .
upon the lowering of the ram, at which time the
channel member is forced to seat in the guide 60 before described. To facilitate the handling of
members 58, considerable friction may be pres
ent between the channel ‘member and the guide
‘ support members thereby necessitating the force
ful ejection of the channel member after com
. pletion of the welds. A suitable foot operated 65
valve 326, as illustrated in Figure 1, is connected
- to the ejecting cylinders 320,through the pipe‘
line 328 and in practice the operator may actu
ate the valve 326 after the ram raises or just
the workpiece in the re-welders 356, 358 and 380
andv for other reasons which will hereinafter ap
pear, the workpiece is inverted after leaving ‘the
pressnwelder. Thus the lateral bend or offset in
the frame member appears reversed in the dia
grammatic showing of the re-welders 366, 358 and
360. It will be obvious that in making frame
‘members for automotive vehicles where such a >
lateral offset is required two sets of press welders
prior thereto, andin the latter case it will be 70 and re-welders will be necessary in order to
handle the right and left-hand workpieces or
frame members but for simplifying the disclosure
herein but a single series of stages will be de
scliiibed
for producing one of the frame members‘
Because of theheavy thickness of the parts to
o y.
be welded, and to supply su?icient welding pres 75
Referring to Figures 12 through 20, there is -
understood that the channel member is thereby
ejected simultaneously with the raising of the
ram.
,
2,378;741
6
is provided so that either roller will engage only
illustrated in detail a re-welder adapted for use
one of the guides at any one time and thus avoid
any interference.
in any one of the three stages following the press
welder stage. In some respects the re-welder is
quite similar to the press welder but since there is
no forming of the cap strip to be effected and
Lateral movement of the table is effected by a
pair of cylinders and pistons 452 as shown in
Figures 14 and 19. Each‘cyllnder and piston
since the channel member and cap piece arrive
at'the re-welder secured together by a plurality
of welds although widely spaced, the press fea
has a piston rod 454 and is geared to the other
piston rod through racks 456 and pinions 458
fixed to the ends of a shaft 488 extending longi
tures including the ram are not present. As
tudinally of the machine from one rack to the
illustrated in Figures 13 and 14, each re-welder 10 other. Each piston rod 454 at its extreme end
has a frame composed of spaced uprights 488, 482,
extends into a ?xed guide 482 and through a
484, 486, 488 and “8 tied together by longitudi
pair of links 484 acts upon a short table oper
nally extending frame members “2 and 4H and
ating lever 466' fulcrumed at 488 in a bearing
transverse members such as 418. Extending cen~
bracket 418. The lever 468 is connected by an
15
trally through the length of the machine is a
adjustable link 412 to a pivoted block 414 carried
work support member “8 consisting of a thin
in a depending bracket 418 secured to the mov—
upstanding plate provided with a top edge 428
able table 428. To move the table to operative
having spaced cleats 422. The top edge 428 has
position air pressure is admitted to the right
a contour complemental to the shape of the beam
hand end of the cylinders 452 through a pipe
or workpiece to be supported thereby and also
line 418 leading to a manually operable valve
has such a lateral offset as is necessary to align
488 (see Fig. 14) and to separate the table air
the same with the lateral offset (as referred to in
pressure is admitted to the left-hand side of the
connection with Fig. 11) of the workpiece. As
cylinder (Figure 19) through pipe line 482 also
illustrated in Figure 12, a plurality of pairs of
leading to the manual valve 488.
25
welding guns 88 and 82 are spacedly arranged
To rigidly secure the workpiece in proper lat
along the length of the apparatus and in a posi
eral position after resting the same upon the
t1on adjacent the workpiece to effect such welds
as may be desired in the particular stage. The
welding guns are identical to those employed in
the press welder previously and hereinabove de
scribed and the details thereof will appear here
inafter.
The welding guns are arranged on' tables 424,
and 426 and such spacing blocks as 428, 438,
.432, 434 as may be necessary to support the guns
in proper relation to the contour of the frame
member or workpiece to be accommodated. The
support member 418 and its transverse cleats 422,
the‘ table 424 is provided with a plurality of
spaced arms 484 (see Figs. 15 and 16) having
30 projections 488 adapted to engage the top side
of one of the ?anges of the'workpiece. The mov
able table 428 is provided with similar arms 488
with projections 488 adapted to engage the upper
side of the other ?ange of the channel of the
35 workpiece. Thus as is illustrated in Figures 15
and 16 upon the movement of the table 428 to
wards table 424 the projections 488 and 488 ap
table 424 may be rigid with the machine as dis
proach the workpiece and securely position and
tinguished from the tables 88 and 88 of the press 40 hold the same during the subsequent welding
welder but the table 428 is laterally movable to
permit placing the workpiece within and remov
ing the workpiece from the machine. The neces
sity for moving but one table in the present in
stance arises from the fact that no pressing oper
ation of the parts occurs in re-welding and there
fore it is not necessary that the workpiece be
inserted by a. pure vertical movement but may
be ‘inserted by a vertical movement and then
laterally slid into place. Thus the movable table
operations.
To effect the welds, the welding guns 8!] and
82 are arranged in ?ve sections, each section
including up to seven pairs of guns and as illus
trated in Figure 12, the sections of the guns
on either side of the machine have common bus
bars and common transformers. As appears in
Figures 13 and 14, each side of the machine is
provided with ?ve welding transformers 482, each
of which is connected to a part of bus bars 484
426 may be moved through a- distance propor 50 and 486 one above the other as is illustrated in
tionately greater or a distance equivalent 'to the
Figure 19. The transformer connections to the
movement of both tables in the press welder.
bus bars are staggered, that is the connection
This feature is illustrated in Figures 15 and 16
to the upper bus bar 484 for example is by a lead
wherein the relative positions of the tables and
488 (see Figure 12) extending to the left-hand
their welding guns and the work support 418 55 end of the bus bar 484 while the other transformer '
and the workpieces are illustrated both in the
welding position and in the loading and unload
lead 588 extends to the right-hand end of the
ing position.
ible connections 582 and 584 to the various weld
The movable table 426 is provided with opposed
spaced roller guides 438 and 488 (Figs. 17 and
18) at four spaced points along the table, the
guides'being secured in spaced relation by an
interposed central block 448. Rollers 442 and
lower bus bar 488. Thus by reason of the ?ex
ing guns from the bus bars 488 and 484 and the
staggered connections the path of current travel
from the transformer to any one welding gun is
maintained substantially constant. The bus bars
484 and 488 are secured to their respective adja
cent tables and those on the left-hand side of
carried in roller bearing blocks 448 secured to the 65 the machine (see Figure 20) are carried with the
frame members 416 and associated frame plates
table in its movement but are connected to its
448. The bearing blocks may have a pin or bolt
transformers through ?exible leads 588 and 588.
intermediate the roller bearings extending
In order to cause successive engagement of the
through a slot ,458 in the guide block between
various welding guns in the various groups, ?uid
70
the guides 436 and 438, the slot being particu
pressure is employed controlled by cam operated
larly arranged to limit the lateral movement of
valves driven by a shaft having a step by step
the table in either direction. It will also be
movement extending along the length of the ma
observed that the rollers have a diameter sub
chine. Such apparatus is illustrated vin Figures
stantially that of the distance between the spaced
75 12, 14. 19 and 20. As illustrated in Figure 19, the
. 444 adapted to roll in the guides 488 and 438 are
parallel guides but that just su?lcient clearance
2,878,741
valve operating cam shaft is indicated by the ref
7
.
and thus while the seventh weld is being effected,
only two pairs of guns will be in engagement with
erence character 510 and is driven from a motor
5l2 through a gear box 514 containing a Geneva
the work and thus only four welds effected, al
though all ten transformers may be energized.
acteristics as that hereinabove described in con 5
To control the operation of the machine auto
nection with the press welder. The gear box is
matically, the cam shaft 5“! beyond the end bear
provided with a shaft 5 I 6 adapted to rotate at the
ing 540 (see Fig. ‘14) is provided with an exten_
rate of one revolution per second and carries a
sion carrying a pair of cams 542 and 544, the cam
welding timer control in the form‘of cam and
542 operating a valve 545 and the earn 544 op~
switch 5|8 and 520, respectively. Through. the
erating a switch 548 adapted to out off the cur~
Geneva movement which is located in the gear
rentv to the cam shaft motor 552 after com
train between the shaft 515 and the valve operat
pletion of all the welds. The valve 545 operate
ing cam shaft 5“! the shaft 5| 0 is caused to ro
ing prior to the switch 548 is adapted to supply
tate in steps of 36 degrees in substantially a
through the pipe line 550 fluid pressure to am
' quarter'of one second and to remain stationary
operating cylinder 552 of the valve 485 to cause
for the remainder of each second and to thereby
the same to actuate so as to effect lateral move
make a complete revolution in ten seconds. Ad
ment of the table 425 away from the work, or in
jacent the valve operating cam shaft 5i0 is a
other words, to supply ?uid pressure to the left
plurality of groups of valves, ?ve groups in all
hand end of the cylinder'452 as illustrated in
movement, having substantially the same char
and each group of which contains seven valves 20 Figure 19. After a new workpiece is inserted into
522, each having cam followers 524 adapted to
engage associated cams 525 located along the
the machine and the table 425 moved into proper
welding position with respect to the workpiece by
manually operating the valve 188, the table, as
length of the cam shaft 5l8. The cams are an
gularly located withrrespect to one another by
an angle of 36 degrees and the effective portion
25
of the 'cam is adapted to lift the rocker arm 524 -
and lower the same during 36 degrees of revo
lution of the shaft or less. Each group of valves
is mounted upon a manifold bracket 528 secured
upon the table 524 and each manifold has a con
nection with each valve mounted thereupon and
all manifolds are connected through a pipe line
538to a common source of ?uid pressure.
The
valves 5,22 and the rockers 524 and other details
thereof are substantially identical to the valves
248 appearing in Figure 8 in conjunction with
the press welder. In Figure 12 some of the valves
have been removed or partially removed in two
of the groups in order to illustrate their position
with respect to the cam shaft 5“). Each of the
valves, as has previously been described, is con
nected to a pair of opposed welding‘guns through
connections as diagrammatically illustrated in
Figure 12 by the dot-dash lines 532, 534, 538 and
by connections shown in full in Figure 20 hear
ing the same numerals. It will be understood
that the pipe lines 535 and 532 for causing en
gagement of the welding electrodes of a pair of
30
it reaches the end of its lateral movement, actu
ates a double pole switch 554 through the cam
555, which switch controls the starting of the cam
shaft operating motor 512 as well as the estab
lishing of current connections to the welding
transformers. The motor 5!: is provided with a
brake 558 which is adapted to stop the same im~
mediately upon the deenergization thereof.
For the automatic pperation of the apparatus,
the wiring diagram may have the arrangement
- as illustrated in Figure 21.
As shown therein
3.3 \a source of three-phase current appears as at
595 which is adapted to operate the valve cam
shaft operating motor 5| 2 through the magnet
ically controlled relay 588. The control of this
relay is effected through a starting button 185
and» the table‘ operated switch 554 which ener
gizcs‘ the magnet 58! of the relay 598, see Figure
19. The table operated switch also'closes the
circuit to the welding transformer timer 102
which is in circuit with the cam operated switch
525 shown in Figure 19. Thus upon the table
moving to the proper position for welding the
motor M2 is set in motion and at the same time
the timer is connected so as to cause the welding
guns are connected in parallel to one side of the
‘transformers to be energized upon each impulse
valve and are adapted to be connected to the 50 produced by the cam operated switch 528. Upon
high pressure source during such interval as the
the completion of all the welds the table is sep
lobe of the cam raises the rocker 524 of the valve.
arated from the- work by reason of the cam
The pipe lines 534 and 538 extend from the other
operated valve 545 and upon the separation of
side of the valve and are adapted to connect, the
the table, switch 554 is opened causing termina
welding guns with high pressure ?uid to sepa 5-3 tion
of the supply of current to the welding
rate the pair of guns at such time as the rocker
transformer. ' Subsequently the cam operated
arm 524 is not in engagement with the lobe of
switch 548 is actuated momentarily‘ opening the
its cam 525. Thus through seven successive steps _ stop circuit for the motor M2 by breaking __the
of movement of the cam shaft all the pairs of
- circuit to the magnet 589 of the relay 558 caus- .
welding guns may be caused to engage the work.‘ 00 'ing the relay to open the circuit to the motor
During each step of such movement and while
5| 2 as well as the‘contacts 104 located in series
certain pairs of guns are in engagement with the i with
the stop switch 185 and cam operated stop
work, one vpair being located in each group, all
switch .545. _
v
“
.
the welding transformers areenergized by the
_ Figure 22 illustrates a slightly different circuit
cam 5| 8 to cause the flow of welding ‘current to 65 employed
in connection with the press welder
I ' effect ten welds provided, ofcourse, that a pair
wherein instead of a two-pole cam operated
of welding guns ‘are actuated in each group, it
‘switch 554 a ram operated switch SIB-is 'em
being'understood that because of the shape of
ployed to close the timing circuit and a separate .
- table operated switch 521 is employed to start
any group may be less than the seven for which 70 the valve operating cam shaft motor 248.
provision is made in the groups of valves, each '
will, of .course, appear that the circuit shown
group. of which contains seven valves. For ex
in Figure 21 may be readily applied to the press .
the workpiece the number, of pairs of guns in
ample, the ?rst, second and ?fth groups from left
welder by employing a two-pole switch such as
554 in place of the switch 32I and by eliminat
guns whereas the third and fourth contain seven 75 ing the ‘ram operated switch M9.
to right of Figure 12 contain six pairs of welding '
2,878,741
in inserting the channel member‘ in the re
welder it is inverted, thus simplifying there
welder by not requiring the provision of space
as is illustrated in Figure 2 a cap strip 33 is in
for the channel member within the machine.
serted and latched in place by the latch mem
Upon insertion of the channel member upon the
bers ‘l6 and a channel member 32 inserted in
guide 4 l8 and in the position shown in Figure 15,
the U-shaped guides 58. vWhile in general the
the manual valve 480 may be operated energizing
channel members are pressed to shape and ‘are
the table moving cylinders 452 and causing the
supposed to ?t within the U-shaped guides 58,
table 426 to move to the position shown in Fig
in practice it is often only possible to partially
insert the channel member into such position 10 urel6 and also as shown in Figures 12, 16, 19 and
20. Upon the table 426 moving to the position
and it is pushed into place upon the lowering of
shown in these ?gures and assuming the start
the ram, the cheek members 58 of the guides
ing button 108 being closed, the cam operated
correctly spacing the ?anges of the channel
switch 554 ‘is actuated closing a circuit to the
member so as to correctly align with the cap
strip 32. The control lever 298 is then lowered 15 motor H2 and setting the cam shaft 5H! in oper
ation as well as the timer shaft 5l6. At the
to the position shown in Figure 1 shifting the
same time the switch 554 completes a circuit to
valve 286 to admit ?uid pressure to the cylinder
the timer which is then actuated at the rate of
46 lowering the ram 40 bringing the central por
From the foregoing description the operation
will readily appear. With the'press welder open
one impulse per second by the cam 5l8 and the
tion of the cap strip into contact with the cen
tral portion of the channel member and by the 20 timer switch 520. The shaft 5|0 simultaneously
commences its step-by-step movement at the rate
weight thereof urging the channel member into
of one step per second effecting the welds of the
position in the guides 58. Thereafter the re
various groups, the welds of each being effected
mainder of the ram including the dies 58 and 10
in sequence and upon completion of the welds
lower forming the cap strip around the contour
i of vthe channel member.
As the ram nearly
‘completes its lowering movement, the valve 308
is tripped operating the valve 310 to cause ?uid
pressure to enter the table operating cylinders
-
O
the cam operated valve 546 causes the table 426
to separate and thereafter the cam switch 548
is actuated opening the connection to the motor
5l2 and applying its brake 558. As the table 426
separates, the switch 554 is opened, opening the
I20 causing the tables to move toward one an
other and placing the welding guns in proper 30 circuit to the welding timer and cutting off the
further supply of welding impulses to the bus
welding position. As the table 94 moves into
bars andvwelding electrodes by the welding trans
position, the switch 32! is actuated setting the
formers. The channel member and its cap strip
motor 2H) in operation, rotating the timer cam
is then removed from the re-welder 353 and
H8 at the rate of one revolution per second
inserted in a re-welder 358 whereupon the same
and the valve operating cam shafts 228-234,
sequence of operations is repeated, and upon the
the latter being given a step-by-step movement,
completion of all the welds to be effected in the
each stepbeing effected in the time of a second.
re-wclder 358, the channel member and cap strip
Upon the lowering of the ram, the switch 319
are removed therefrom and placed in the re
is, closed and thereafter the welding transformers
v2M are all energized each time the timer cam 40 welder 380 where the operation is again repeated.
It will be understood that the position of the
2 l8 makes a revolution, the duration of energiza
~ tion depending upon the setting of the welding
timer which may be varied to accommodate dif-,
ferent thicknesses of material and welding cur
rent required. Through the operation of‘the
cam shafts 228-234 the valves controlling the
various-welding guns are sequentially actuated
and the various welds, twelve in number for each
welding guns for the various re-welders as well
as the welding guns of the press welder will be
such as to ?nally effect a predesired uniform
arrangement of spot welds along the ?anges of
the channel membér and the cap strip and that
suitable guides such as 353 will be provided in
conjunction with each of the re-welders so as
to assure the positioning of the channel member
group, effected between the ?anges of the chan
nel member and the cap strip. Upon the com 50 and its cap strip in the correct position longi
tudinally with respect to the welding guns.
pletion of theiwelds and the further rotation of
Since it will ‘be observed that there are a great
the cam shaft 228, the valve 280 is actuated
er number of operations to be performed in con
which controls the operation of the valve 3I0
junction with the press welder, that is the same
causing the table operating cylinders I20 to sep
must vbe loaded not only with a channel member
arate the tables. Shortly there-after and before
but also a cap strip and that time is taken for
a complete revolution of the cam shaft 228, the
the operation of the ram in pressing the cap
cam operated switch 214 is actuatedcutting off
strip into shape about the channel member, the
the supply of current to the motor 210 where
number of welds effected by the press welder are
upon the brake 2“ is applied immediately stop
ping the cam shaft. Simultaneous with the oper
ation of the valve 3l0 the hand c'ontrol lever 298
is returned to the upper position as shown- in
dotted lines in Figure. l by reason of pressure ap
60 reduced in number so that over-all operation of
the press welder may have a time substantially
that of the re-welders. This is accomplished by
causing the press welder to effect only six welds
per group whereas the re-welders in some in
plied to cylinder 3“ and the ram is lifted to the '
position shown in Figure 2. The channel mem 65 stances effect seven welds per group. Thus the
rber may then be'ejected by actuation of the
time interval of one second is saved to allow the
ejecting cylinders 320 through actuation of the
operators a sufficient time to perform the addi
tional steps of loading which are required of
pedalcontrolled valve 326 and the channel mem
them. By such means the press welders and re
her and cap strip welded together at spaced
points may then beremoved from the machine. 70 welders are‘ adapted to be operated in substan
tially the same length of time so that channel
The channel member and cap strip are there
members may be fed through the sequence of
after placed in a re-welder 356, the table 426 of
machines in a smooth orderly fashion.
I
the re-welder being separated as is shown in Fig
It will appear that in both the press welder
ure 15 to permit the insertion of the channel
member and cap strip. It will be observed that 76 and the re-welders the welding guns depend
2,378,741
downwardly with respect; to the ?anges in which
the welds are to be effected. Thus the welding
guns, for example in Figure 1, tend to. interfere
with one another where the curvature is convex
as at 330 and tend to afford plenty of space
where the curvature appears concave.
This per- -
mits the closer spacing of the" welding guns
where the curvature is concave than where the
curvature is convex. However, when the chan
nelmember is turned upside down as it is in plac
' ing the same in the re-welders, the convex cur
vature in reality becomes concave and the con
cave curvature becomes convex thus resulting in
the welding guns being crowded at points on the
9
depending below, andthis is especially desirable
since the cap strip must be welded suf?ciently
frequently along concave curvature to assure its
close conformation to the channel member, and
to prevent it from arranging itself in- chords from
weld to weld, which would, if welds were spaced
too far apart, result in space between the cap
strip and channel. Where the curvature is con
' vex, this obviously is not necessary and the weld
spacing may be relatively great.
Though only one example of apparatus is dis
closed, however the apparatus being composed of
modi?ed forms of a generic structure, it is to be
understood that the invention is not limited there
, re-welder where space was ample in the press 15
to but may be embodied in various mechanical
welder. Thus by turning over the channel mem
ber as it progresses from the press welder to the
re-welders, it is possible to supply the welds in
great number and close spacing where greater
than normal spacing is’ required in the press
welder. Thus considerable advantage is present
in providing the welding guns with the bulk there
of on one side of the ?ange to be welded and
forms. As many changes in construction, oper
ation and arrangement of the mechanism and
parts may be made without departing from the
spirit of the invention as will be well understood
by those skilled in the art, reference will be had
to the appended claims for a de?nition of the lim
its of the invention.
This invention relates principally to apparatus
in reversing the channel'as it progresses through
having
spot welding electrodes of the ?oating
the series of machines.
25 type, that is, in which each electrode is adapted
While the apparatus has been described as a
to be movable so that where a number of pairs of
" series of machines for accomplishing a series of
separate
electrodes are used, as in spotrwelding,
operations and producing a finished box girder,
the
pressure
transmitted to the work by each pair
it will appear that great similarity exists, be
of electrodes will be uniform with the pressure
tween the press welder and the re-welders and 30 transmitted by each other pair of electrodes to
that they are, in fact, modi?cations of one an
obtain uniformity in the work irrespective of
other, the press welder being modi?ed from the
whether
the work be of precisely uniform thick
re-welders by being .provided with duplicate ta
ness and whether the electrodes are each of ex
ble movement and the addition of the press fea
actly the same length. The use of tables, as
ture.
35 described, which are capable of being relatively
In both machines, the blocks I00, I02 and I04,
separated laterally to allow the work to be in—
428 and 434 may be quickly changed to suit
serted and the pressing ram to operate, and are
changes in workpiece shape, and also the dies
then adapted to be automatically closed in re
68, ‘HI and ‘H may be readily removed and changed
sponse
to the completion of the ramming oper
by removing the bolts 15..
40 ation, facilitates insertion of the work as well as
It will thus appear that an automatic appara
shortening the time necessary for a cycle of oper
tus is provided for e?ecting closely spaced spot
ation. Each welding gun contains a ?uid pres
welds along the length of channel members and
sure device, and is compact since the pressure
the like, capable of precise duplication and rapid
piston and cylinder are arranged vertically within
operation. The apparatus by varying the air
the gun for direct cooperation with the welding
pressure on the welding guns and by varying the
electrodes ,to avoid any diminution in the power
current as well as the time for welding is capable
transmitted to the electrodes by the ?uid pressure
of great ?exibility and adaptability for different
piston and cylinder. The ease of removing any
thicknesses of metal to be worked upon. Fur
gun upon removal of the electrical and ?uid pres
ther by changing the shape of the blocks located
sure connections aids the rapid operation and
upon the table and upon which the welding guns
servicing of this device.
are positioned, the apparatus may be readily
Certain features of the machines as illustrated,
changed to accommodate changes in shape of
and described are claimed in applicant's applica
the ?anged members or workpieces as may be
tion Serial No. 291,838, for Press welding machine,
necessary. The apparatus is rugged, repairs such 55 ?led
August 25, 1939, now Patent No. 2,319,095,
as are necessary due to operation are readily ef
fected without dismantling the entire machine,
and duplication ofworkeis assured. In practice
dated May 11, 1943, of which the present applica
tion is a division. The disclosed welding gun and
its details form the subject matter of applicant’s
apparatus such as herein described is capable of=
application Serial No. 408,418, for Welding gun,
effecting over two hundred uniform sound spot 60 ?led August 27, 1941, now Patent No. 2,341,133,
welds in less than ?fteen seconds. . '
dated February 8, 1944, which is another division
While the apparatus has been illustrated as _
of the aforesaid parent application.
effecting one weld per second, and a complete
What is claimed is:
machine ‘cycle of ten seconds, it will appear ob
1., The method of welding a member such as
vious that variationsmay be made in time'cf ‘y r
effecting a weld, as well as the number e?fected‘
per machine cycle. Further, the time relation
' I between pressure build up, welding time, dwell
a cover plate on a second member such as a lon
gitudinal ?anged channel member by a plurality
of closely spaced spot welds, said members having
a reverse curve along the length thereof, resulting
and release'may be changed to suit conditions
in convex portions and concave portions, which
and the pressure employed may be varied to suit 70 comprises
effecting a plurality of closely spaced
changes in thickness of metal operated upon.
welds
along
the concave portion with apparatus
. It will also appear from Figs. land 2 that con
arranged normal to the curvature and the bulk
cave portions of the workpiece are susceptible ' of
which is located on the opposite side of the
of being welded at close points because of lack
members
the center of curvature, while
of interference from the bulk of the welding guns 75 e?'ecting afrom
pluralltyof more widely spaced welds
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