Welding machine

A welding machine can form continuous welds of three hundred and sixty degrees on workpieces which are rotated through angles of less than three hundred and sixty degrees by moving the welding torch of that welding machine in one direction circumferentially of those workpieces while those workpieces are being rotated in the opposite direction.

This invention is an improvement on the welding machine (hereinafter 
patented welder) which is disclosed and claimed in my U.S. Pat. No. 
3,970,232 which was granted on July 20, 1976. 
BACKGROUND OF THE INVENTION 
When one element of a workpiece is to be welded to another element of that 
workpiece, it frequently is desirable to form a continuous weld of three 
hundred and sixty degrees angular extent at the joint between those two 
elements; and the patented welder can provide such a weld where either of 
those elements can be rotated through three hundred and sixty degrees. 
However, some workpieces have forms and configurations which preclude 
their rotation through three hundred and sixty degrees while those 
workpieces are mounted in a welding machine. In fact, workpieces are known 
which can be rotated only through two hundred and seventy degrees while 
they are mounted in a welding machine. Although it would be possible to 
provide a three hundred and sixty degree weld at the point between two 
elements of such a workpiece, by successively mounting that workpiece in 
two different positions in the patented welder, that weld would not be 
homogeneous. Also, valuable time would be required to successively mount 
that workpiece in those two different positions. 
SUMMARY OF THE INVENTION 
The present invention makes it possible to provide a continuous weld of 
three hundred and sixty degrees angular extent at the joint between two 
elements of a workpiece, even though that workpiece can be rotated only 
two hundred and seventy degrees; and it does so by moving the welding 
torch of a welding machine in one direction circumferentially of that 
workpiece while that workpiece is being rotated in the opposite direction. 
The circumferential travel of the welding torch in the one direction 
combines with the rotation of the workpiece in the opposite direction to 
provide relative rotation between that welding torch and that workpiece of 
three hundred and sixty degrees. It is, therefore, an object of the 
present invention to provide a welding machine which can provide a 
continuous weld of three hundred and sixty degrees angular extent on a 
workpiece which is rotated less than three hundred and sixty degrees by 
moving the welding torch of a welding machine in one direction 
circumferentially of that workpiece while that workpiece is being rotated 
in the opposite direction. 
The welding machine of the present invention moves the welding torch 
thereof tangentially of the axis of rotation of the workpiece while 
simultaneously moving that welding torch radially of that axis. The rate 
and extent of that tangential movement can be correlated with the rate and 
extent of that radial movement to provide a circumferential movement of 
that welding torch which is the complement of the surface of the 
workpiece. As a result, the tangential and radial movement of the welding 
torch enables the resulting composite circumferential movement of that 
welding torch to closely "track" the joint in the workpiece that is to be 
welded. It is, therefore, an object of the present invention to 
simultaneously move the welding torch of a welding machine both 
tangentially and radially of the axis of rotation of a workpiece to 
provide a composite circumferential movement for that welding torch which 
can closely "track" the joint which is to be welded. 
Other and further objects and advantages of the present invention should 
become apparent from an examination of the drawing and accompanying 
description. 
In the drawing and accompanying description a preferred embodiment and an 
alternate embodiment of the present invention are shown and described but 
it is to be understood that the drawing and accompanying description are 
for the purpose for illustration only and do not limit the invention and 
that the invention will be defined by the appended claims.

DESCRIPTION OF THE PREFERRED AND ALTERNATE EMBODIMENTS 
Referring to FIGS. 1-11 in detail, the numeral 20 denotes a 
vertically-directed portion of a wide metal plate, the numeral 22 denotes 
a bend line in that plate at the lower edge of portion 20, and the numeral 
24 denotes a downwardly and rearwardly-inclined portion of that plate. The 
numeral 26 denotes a bend line at the lower edge of portion 24, the 
numeral 28 denotes a horizontally-directed, rearwardly-extending portion 
of that plate, and the numeral 30 denotes an upwardly-bent flange at the 
rear edge of portion 28. The numeral 32 denotes a bend line at the upper 
edge of portion 20 of the metal plate; and the numeral 34 denotes a 
portion of that plate which is horizontally-directed and which extends 
rearwardly from that bend line. The numeral 36 denotes a bend line at the 
rear of portion 34; and the numeral 38 denotes a portion which inclines 
upwardly and rearwardly from that bend line. The numeral 40 denotes a bend 
line between portion 38 and a vertically-directed portion 42 of that 
plate. The portions 20, 24, 28, 30, 34, 38 and 42 preferably will be 
identical to the identically-numbered portions of the corresponding plate 
in the patented welder. 
The numeral 44 denotes a prismatic enclosure which has the inner wall 
thereof welded to the adjacent edges of the portions 20, 24, 28, 30, 34, 
38 and 42 of the wide metal plate. Openings 45 and 47 are formed in that 
inner wall, as shown particularly by FIG. 2. Feet 46 are provided for that 
enclosure, as shown by FIG. 1. The numeral 48 denotes a prismatic 
enclosure which is similar to the enclosure 44; and the inner wall of that 
enclosure is welded to the adjacent edges of portions 20, 24, 28, 30, 34, 
38 and 42 of the wide metal plate. Feet 50 are provided for that 
enclosure, as indicated by FIGS. 1 and 2. Openings, not shown, which are 
comparable to the openings 45 and 47 in the inner wall of enclosure 44, 
are provided in the inner wall of the enclosure 48. Except for the opening 
47 and its counterpart, the enclosures 44 and 48 preferably will be 
essentially identical to the similarly-numbered enclosures in the patented 
welder. 
The numeral 52 denotes a bearing housing at the left-hand face of the inner 
wall of enclosure 44, as shown by FIGS. 1, 3 and 6; and the numeral 54 
denotes a similar bearing housing at the right-hand face of the inner wall 
of enclosure 48. An elongated shaft 56 extends through openings, not 
shown, in the inner walls of enclosure 44 and 48 and through the bearing 
housings 52 and 54 to support a sprocket gear 58 and a cam 60 within 
enclosure 44 and to support a sprocket gear 68 and a cam 66 within 
enclosure 48. The bearing housings 52 and 54, the shaft 56, and the 
sprocket gears 58 and 68 preferably will be identical to the 
identically-numbered components of the patented welder. 
Referring particularly to FIG. 2, the numeral 91 denotes a movable plate 
which coacts with a fixed upper plate to constitute a clamp 98. Spherical 
recesses at the inner surfaces of those plates receive a ball 101 at the 
rear end of a supporting plate 100. That supporting plate is thin enough, 
relative to the space between the plate of clamp 98, to enable that 
supporting plate to be tilted at any desired angle and to be rotated to 
any desired position. Once the plate 100 has been given a desired 
position, set screws 102 can be tightened to urge the plates of clamp 98 
into holding engagement with the ball 101. The clamp 98 extends forwardly 
from a horizontally-directed portion 96 of a non-linear arm of an 
elongated, angular, pivoted support 442. That non-linear arm has a 
rearwardly and upwardly-inclined portion 92, and a vertically-directed 
portion 94; and the latter portion is contiguous to the 
horizontally-directed portion 96. The numeral 103 in FIGS. 2 and 3 denotes 
a split-sleeve holder for a welding torch 104; and that holder is secured 
to the plate 100 by a screw 105. 
The movable plate 91, the inclined portion 92, the vertical portion 94, the 
horizontally-directed portion 96, the clamp 98, the supporting plate 100, 
the ball 101, the set screws 102, the holder 103, the torch 104, and the 
screw 105 preferably will be identical to the identically-numbered plates, 
portions, clamp, ball, screws, holder and torch in the patented welder. 
However, the lower portion of the elongated, angular, pivoted support 442 
differs from the lower portion of the corresponding elongated, angular, 
pivoted support in the patented welder. 
Referring particularly to FIG. 2, the numeral 150 denotes two plates which 
are secured to the lower portion of the inner face of the front wall of 
enclosure 44 to constitute a pivot bracket; and a pivot 152 secures an 
elongated horizontally-directed arm 154 to that bracket. A pneumatic 
cylinder 156 has the lower end thereof secured to the bottom of enclosure 
44 by small plates 160 and a pivot 158. The piston 162 of that cylinder 
has a clevis-like upper end 164; and a pin 166 secures that upper end to 
lever 154. A pivot 168 rotatably secures a roller 170 to the arm 154; and 
that roller engages, and serves as a follower for, cam 60. A pin 172 
connects the lower end of an adjustable-length link 182 to the free end of 
arm 154. Small plates 174 at the left-hand face of the inner wall of 
enclosure 44 support a pivot 176 which supports a hub adjacent the lower 
edge of a generally-triangular plate 178. A pin 180 is carried by the 
outer end of triangular plate 178, and it secures that plate to the upper 
end of the adjustable-length link 182; and a pin 184 secures the upper end 
of that plate to an adjustable-length link 188. Arm 154, cylinder 156, 
piston 162, triangular plate 178, and adjustable-length links 182 and 188 
will preferably be identical to the identically-numbered corresponding 
components of the patented welder; and they will preferably be supported 
and guided by components which are identical to corresponding components 
in that patented welder. 
A bearing housing 198 in FIGS. 1 and 3 is secured to the inner wall of 
enclosure 44; and a pivot 200 is supported by that housing. A sprocket 
gear 202 is mounted on and rotates with that pivot. That bearing housing, 
pivot and sprocket gear will preferably be identical to the 
identically-numbered corresponding elements in the patented welder. 
The numeral 212 in FIGS. 1 and 3 denote a pivot block at the upper portion 
of the inner face of the outer wall of enclosure 44; and the numeral 214 
denotes a similar pivot block at the upper portion of the inner wall of 
that enclosure. A shaft 216 is rotatably held by bearings within those 
blocks; and a sprocket gear 218 and a slip ring 232 are fixedly mounted on 
that shaft. A bracket 222 at the inner face of the outer wall of enclosure 
44 supports an elongated resilient arm 224 which holds an electrical brush 
230 in engagement with the slip ring 232. Pivot blocks 250 and 252, a 
hollow rotatable shaft 254, a sprocket gear 256, a slip ring 258 and an 
electrical brush 260 are mounted within the enclosure 48, as shown by FIG. 
1. The shafts 216 and 254, the pivot blocks therefor, the sprocket gears 
218 and 256, the slip rings 232 and 258, and the electrical brushes 230 
and 260 will preferably be identical to the identically-numbered 
corresponding components of the patented welder. 
The numeral 236 denotes an electric motor which is disposed within the 
enclosure 44, as shown by FIGS. 1-3; and a gear housing 238 is secured to 
the lower end of that motor. Screws 240 secure that gear housing to the 
rear wall of enclosure 44, as shown by FIGS. 2 and 3. The output shaft 239 
of that gear housing has a sprocket gear 234 mounted on it to drive a 
sprocket chain 400. That sprocket chain engages and drives sprocket gears 
58, 202 and 218, and also engages and drives a sprocket gear 402 which is 
mounted on and rotates with a pivot 404 in the upper left-hand portion of 
FIG. 2. Sprocket gear 58 will rotate the shaft 56, and will thereby rotate 
the sprocket gear 68 in the enclosure 48. A sprocket chain 268 within 
enclosure 48 is driven by the sprocket gear 68; and that sprocket chain 
drives sprocket gear 256 and shaft 254 and also drives a sprocket gear, 
not shown, that is similar to sprocket gear 202 and that is mounted on a 
pivot which is rotatably held by a bearing block 264 within enclosure 48. 
The numeral 542 in FIG. 1 denotes an elongated, angular, pivoted support 
which will preferably be identical to elongated, angular pivoted support 
442. The elongated, angular pivoted support 542 has a slotted clamp 246 
which holds a plate 248 to which a welding torch, not shown, can be 
secured. 
The numeral 262 in the upper right-hand portion of FIG. 1 denotes a 
rotation-enabling coupling which is mounted on the outer end of the hollow 
shaft 254. That coupling provides an air-tight seal between the hollow 
center of that shaft and an air hose 263, while permitting that air hose 
to remain stationary despite rotation of that shaft. 
The numeral 270 denotes a pivot which is suitably secured to the inner wall 
of enclosure 48, as indicated by FIG. 1; and that pivot is generally in 
register with the pivot 176 within enclosure 44. A generally-triangular 
plate 272 is rotatably mounted on pivot 270; and a vertically-directed 
adjustable-length link 274 connects the outer end of that plate to the 
rear end of an elongated horizontally-directed arm 273. A pin 276 at the 
upper end of plate 272 supports one end of a horizontally-directed 
adjustable-length link 278 which has the other end thereof pivotally 
connected to the elongated, angular, rotatable support 542. Pivot 270, 
plate 272, elongated arm 273, pin 276, and adjustable-length links 274 and 
278 will preferably be identical to the identically-numbered, 
corresponding components of the patented welder. 
The numeral 282 denotes a face plate which is mounted on the inner end of 
shaft 216, as shown by FIGS. 1 and 3. The numeral 284 denotes a similar 
face plate which is mounted on the inner end of the shaft 254, as shown by 
FIG. 1. The axes of those shafts, and hence the axes of those face plates, 
are coincident. 
The numeral 406 in FIGS. 2 and 3 denote a cam which is mounted on, and 
rotates with, the shaft 404. The numeral 408 denotes a pivot which is 
secured to the inner wall of enclosure 44 by a boss 409, as shown 
particularly by FIG. 6; and that pivot supports an elongated, straight, 
vertically-directed lever 410, as shown particularly by FIG. 2. A roller 
412 is rotatably secured to the upper end of lever 410 by a pivot 411; and 
that roller engages, and serves as a follower for, the cam 406. 
The numeral 414 denotes a pivot which is secured to the inner wall of 
enclosure 44 by a boss 415, as shown by FIG. 3. A similar pivot, not 
shown, is secured to the inner wall of enclosure 48 by a similar boss, not 
shown. A large U-shaped bracket 418 has the closed portion thereof 
extending across the space between the inner walls of enclosures 44 and 
48, as indicated particularly by FIGS. 1, 3 and 6; and the left-hand arm 
416 of that bracket is generally horizontally-directed, and it extends 
rearwardly along the inner face of the inner wall of enclosure 44 as 
indicated by FIGS. 3 and 4. A short, vertically-directed plate 420 is 
welded or otherwise secured to the arm 416; and it extends downwardly from 
that arm, as indicated particularly by FIG. 4. A pivot 424 rotatably 
secures a roller 422 to that plate; and that roller engages, and serves as 
a follower for, a cam 426 which is mounted on shaft 56, as shown 
particularly by FIGS. 2, 4 and 6. A similar cam 427 is mounted on the 
other end of shaft 56 adjacent the inner wall of enclosure 48. A roller 
429, that is mounted on the end of a plate which is similar to plate 420 
and which extends downwardly from the other arm of U-shaped bracket 418, 
engages, and serves as a follower for, the cam 427, as indicated by FIG. 
1. 
The numeral 430 denotes an elongated hollow beam of rectangular cross 
section; and that beam is disposed between the arm 416 and the other arm, 
not shown, of the U-shaped bracket 418. Aligned openings in those arms are 
aligned with openings in end plates, not shown, for that beam, and also 
are aligned with the opening 47 in the inner wall of enclosure 44. 
Thereafter, the outer wall of enclosure 44 is removed; and then an 
elongated shaft 428 is successively inserted through opening 47, the 
opening in arm 416, the opening in the left-hand end plate of beam 430, 
through the full length of that beam, through the opening in the 
right-hand end plate of that beam, and then into the opening in the other 
arm of U-shaped bracket 418. That shaft will enable that U-shaped bracket 
to support that beam; but that shaft will be rotatable relative to the 
arms of that bracket. The opening 47 has a vertical axis which is longer 
than the horizontal axis of that opening; and hence that opening permits 
vertical movement of the shaft 428, and hence of the beam 430. Pins, not 
shown, pass through collars on the end plates of beam 430 and also through 
the shaft 428 to force that beam and shaft to rotate as a unit. 
The numeral 432 denotes a U-shaped bracket which encases the front, top and 
bottom of a short length of the beam 430, as shown particularly by FIGS. 6 
and 7. Retainer plates 434 are disposed at the rear face of that beam and 
in engagement with the outer ends of the horizontally-directed upper and 
lower flanges of bracket 432. Screws 436 extend through those retainer 
plates and seat in threaded sockets in those horizontally-directed flanges 
to enable bracket 432 and those plates to closely encircle beam 430. Set 
screws 438 pass through the retainer plates 434 to bear against the rear 
face of beam 430, and thereby fix the axial position of bracket 432 on 
that beam. By loosening and then re-tightening the set screws 438, it is 
possible to shift the bracket 432 to any desired position along the length 
of beam 430. However, once those set screws have been tightened, the 
bracket 432 will move as a unit with the beam 430. 
The elongated, angular, pivoted support 442 has a deep, 
horizontally-directed portion at the front thereof, as shown particularly 
by FIG. 7; and a flat plate 444 abuts, and extends forwardly beyond, the 
upper surface of that portion. A flat plate 446 abuts, and extends 
forwardly beyond, the lower surface of that portion. The plate 444 will 
preferably be welded to the upper surface of the deep, 
horizontally-directed portion of the pivoted support 442; and screws will 
releasably secure the lower plate 444 to that portion. Shouldered screws 
440 extend through openings in the forward ends of the plates 444 and 446 
and seat within threaded sockets in the upper and lower flanges of the 
bracket 432. Those screws serve as pivots to permit those plates, and 
hence the pivoted support 442, to pivot about the vertical axis which is 
defined by those screws. The forward edge 443 of the deep, 
horizontally-directed portion of the pivoted support 442 is spaced 
rearwardly of the rear face of the beam 430 to keep that forward edge from 
limiting rotation of that pivoted support. 
A pin 448 pivotally secures the inner end of the adjustable-length link 188 
to the plate 444 and to the deep, horizontally-directed portion of the 
pivoted support 442. As a result, that adjustable-length link can respond 
to rotation of the triangular plate 178-- which is caused by cam 60, cam 
follower 170, arm 154 and adjustable-length link 182-- to rotate the 
elongated, angular, pivoted support 442 about the axis which is defined by 
the screws 440. A pin, not shown, which is similar to pin 448 will connect 
the inner end of adjustable-length link 278 to the deep, 
horizontally-directed portion of the elongated, angular, pivoted support 
542 in FIG. 1 to enable that pivoted support to rotate in response to cam 
66, arm 273, adjustable-length link 274, and triangular plate 272. 
Referring particularly to FIGS. 2 and 6, the numeral 450 denotes an 
elongated straight lever which has a hub 452 at the lower end thereof; and 
that hub telescopes over and is fixedly secured to that portion of pivot 
428 which extends outwardly through the opening 47 in the inner wall of 
enclosure 44. That clamp will force that pivot, and hence the elongated 
beam 430, to rotate as a unit with the lever 450. j 
A pivot bracket 454 is secured to the upper portion of the inner face of 
the front wall of enclosure 44, as shown particularly by FIG. 2; and a 
pivot 456 rotatably secures a pneumatic cylinder 458 to that pivot 
bracket. The piston 460 of that cylinder has a clevis-like outer end 462 
which telescopes over a portion of the upper end of lever 450; and a pin 
464 secures that clevis-like end to that lever. The numeral 466 denotes a 
horizontally-directed connecting rod which is pivoted to lever 410 by a 
pin 468 and which is pivoted to the lever 450 by a pin 470. 
As shown particularly by FIGS. 2-5, a U-shaped bracket 472, which underlies 
the arm 416 of U-shaped bracket 418, is secured to the inner wall of 
enclosure 44. A pivot 474, which is journaled in bracket 472, extends 
through that inner wall to interrelate a cam 476 with a crank 480; so 
rotation of that crank will enforce rotation of that cam. That cam has a 
flat 478 thereon, as indicated particularly by FIG. 4. 
The cam 476 underlies the arm 416 of U-shaped bracket 418; and that cam 
will normally be in the lower position shown by solid lines in FIG. 4. As 
long as that cam is in that lower position, the roller 422 will be 
permitted to bear against the cam 426 and to respond to the "rises" and 
"falls" on that cam to raise and lower bracket 418, pivot 428, beam 430, 
and elongated angular pivoted support 442. However, when the crank 480 is 
used to set cam 476 in the dotted-line position of FIG. 4, the flat 478 
thereon will hold the arm 416 far enough above the cam 426 to keep the 
highest "rise" or "dwell" on cam 426 from engaging the roller 422. As a 
result, when the cam 476 is in that dotted-line position, it will force 
the U-shaped bracket 418 to raise the adjacent end of beam 430 to a level 
at which that beam will not be raised or lowered by cam 426 and follower 
422. A bracket, pivot, cam and crank, not shown, which are identical to 
bracket 472, pivot 474, cam 476 and crank 480, are provided adjacent the 
inner wall of enclosure 48 to selectively hold the other arm of U-shaped 
bracket 418, and hence the other end of beam 430, in raised position. By 
rotating the crank 480 and its counterpart from their lower positions to 
their upper positions, the operator of the welding machine can easily fix 
the vertical position of the beam 430. However, whenever it is desirable 
to have that beam rise and fall, the crank 480 and its counterpart will be 
set to permit cams 426 and 427 to coact with followers 422 and 429, 
respectively, to raise and lower bracket 418 and beam 430. 
Referring particularly to FIGS. 1 and 3, the numeral 490 denotes a fixture 
which is generally rectangular in plan and which is generally planar in 
elevation. That fixture has upstanding ends 489 which are securable to the 
confronting faces of the face plates 282 and 284, as shown by FIG. 1. That 
fixture has a U-shaped opening 491 adjacent the midpoint of the rear edge 
thereof, as shown by FIG. 3. A V-block 492, which serves as a stop for a 
workpiece 496, is located adjacent one end of the upper surface of fixture 
490; and pneumatic cylinders 494 are located adjacent the opposite end of 
that upper surface. That workpiece is shown as having a tubular portion 
498 of relatively-large diameter and two tubular portions 500 and 502 of 
smaller diameter. To facilitate the positioning of the smaller-diameter 
tubular portions 500 and 502 at right angles to the axis of tubular 
portion 498, as shown particularly by FIG. 3, the ends of those tubular 
portions may be notched to conform to the surface of the tubular portion 
498. The tubular portions 500 and 502 can be held at the proper angle 
relative to the tubular portion 498 by conventional fixture tooling. When 
the pistons 495 of the cylinders 494 bear against the right-hand ends of 
the tubular portions 500 and 502, as indicated by FIG. 1, those tubular 
portions will force the tubular portion 498 into holding engagement with 
the V-block 492. FIGS. 1, 3 and 9-11 show the tubular portion 502 abutting 
the tubular portion 498 while the joint between the latter tubular portion 
and tubular portion 500 is being welded; and that was done to show that 
after one of the tubular portions 500 and 502 has been welded to the 
tubular portion 498, the other of the tubular portions 500 and 502 would 
strike the welding torch 104 if the workpiece were to be rotated through 
more than two hundred and seventy-degrees. In actual practice, the tubular 
portion 502 will not be assembled with the tubular portion 498 until after 
the joint between the latter tubular portion and tubular portion 500 has 
been welded. 
As shown particularly by FIG. 3, the joint between the tubular portion 500 
and the tubular portion 498 overlies the U-shaped opening 491 in the rear 
edge of fixture 490. As a result, if the workpiece 496 could be rotated 
three hundred and sixty degrees, the welding torch 104 could provide a 
continuous weld of three hundred and sixty degrees angular extent for the 
joint between the portions 498 and 500 without raising or lowering that 
torch. However, because the tubular portion 502 would strike the welding 
torch 104 if the workpiece 496 were to be rotated through three hundred 
and sixty degrees after the joint between the tubular portions 498 and 502 
had been welded and while the joint between the tubular portions 498 and 
500 was being welded, it is necessary to limit the rotation of that 
workpiece to an angle substantially less than three hundred and sixty 
degrees. 
To enable the welding torch 104 to provide a continuous weld of three 
hundred and sixty degrees for the joint between the portions 498 and 
500--even though the workpiece 496 is rotated less than three hundred and 
sixty degrees--that torch is moved vertically through a path which will 
keep the tip of that torch an essentially-fixed distance from the joint 
which is to be welded. Because the portions 498 and 500 of the workpiece 
496 are right-circular cylinders and are normal to each other, the 
vertical path for the welding torch 104 is a simple arc of constant radius 
about the axis of the portion 500. However, if the portion 500 were to be 
L-shaped, U-shaped or otherwise polygonal in cross section, the vertical 
path for the welding torch 104 would be exceedingly complex; because it 
would have to repeatedly include movements of the tip of that torch 
through varying distances horizontally relative to that axis during the 
progressive movement of that torch in the vertical direction. By providing 
appropriate "rises" and "falls" on the cams 426 and 427, and by providing 
appropriate "rises", "falls" and "dwells" on the cam 406, the cam 
followers 422 and 429, bracket 418, pivot 428, beam 430 and elongated 
arcuate pivoted support 442 will provide the required vertical component 
of motion, and the cam follower 412, levers 410 and 450, connecting rod 
466, pivot 428, beam 430 and elongated arcuate pivoted support 442 will 
provide the required horizontal component of motion. Simultaneously, 
appropriate "rises", "falls" and "dwells" on the cam 60 will cause cam 
follower 170, arm 154, adjustable-length links 182 and 188, and beam 430 
and elongated arcuate pivoted support 442 to provide the horizontal 
lateral movement of the outer end of torch 104 which is needed to 
continuously hold the tip of that torch at an optimum angle relative to 
the joint which is to be welded. 
Different sets of cams 60, 426 and 427, and 406 will be required for each 
individually-different workpiece. To weld the joint between the portions 
498 and 500 of workpiece 496, the welding torch 104 must twice be moved 
through the horizontal distance adjacent the notation Radial Motion 
Control in FIG. 8 while it is moved once through the vertical distance 
adjacent the notation Rise & Fall Motion in that view. The resulting 
composite motion of the tip of that torch is denoted by the numeral 642 in 
FIG. 8; and the ninety degrees of that composite motion add to the two 
hundred and seventy degree rotation of tubular portion 500, which is 
denoted by the numeral 644, to provide the desired relative movement of 
three hundred and sixty degrees between that tubular portion and that tip. 
In welding the joint between the portions 498 and 500 of workpiece 496, the 
cylinder 458 will initially act through piston 460, lever 450, beam 430 
and elongated angular pivoted support 442 to hold the welding torch 104 an 
appreciable distance to the left of the position shown by FIG. 2 so the 
motor can rotate the workpiece 496 to the position shown by FIG. 9. 
Thereafter, that cylinder will act through that piston and lever, 
connecting rod 466 and lever 410 to hold cam follower 412 in engagement 
with cam 406, and thereby dispose the welding torch in the dotted-line 
Radial Motion Control position in FIG. 8. At that same time, cams 426 and 
427, cam followers 422 and 429, U-shaped bracket 418, pivot 428, beam 430 
and elongated angular pivoted support 442 will be holding welding torch 
104 in the solid line Rise & Fall Motion position in FIG. 8; and cam 60, 
cam follower 170, arm 154, adjustable-length links 182 and 188, and 
elongated angular pivoted support 442 will be holding the tip of that 
welding torch at an optimum angle relative to the joint between the 
portions 498 and 500. 
Thereupon, the motor 236 will cause the fixture 490 to rotate the workpiece 
496 in the clockwise direction from the position of FIG. 9 to the position 
of FIG. 11. During the one hundred and thirty-five degrees of rotation of 
that workpiece, from the position of FIG. 9 to the position of FIG. 10, 
the cams 426 and 427 and the components responsive thereto will cause the 
welding torch 104 to move downwardly from the position of FIG. 9 to the 
position of FIG. 10, and cam 406 and the components responsive thereto 
will cause that welding torch to move outwardly from the position of FIG. 
9 to the position of FIG. 10. The resulting forty-five degree composite 
motion of that welding torch will coact with the one hundred and 
thirty-five degree rotation of workpiece 496 to permit a continuous weld 
of one hundred and eighty degrees. The motor 234 will cause the workpiece 
496 to continue its uninterrupted rotation toward the position of FIG. 11; 
and, during the one hundred and thirty-five degrees of rotation of that 
workpiece from the position of FIG. 10 to the position of FIG. 11, the 
cams 426 and 427 and the components responsive thereto will cause the 
welding torch 104 to move downwardly from the position of FIG. 10 to the 
position of FIG. 11, but cam 406 and the components responsive thereto 
will cause the welding torch to move inwardly from the position of FIG. 10 
to the position of FIG. 11. The resulting forty-five degree composite 
motion of that welding torch will coact with the one hundred and 
thirty-five degree rotation of workpiece 496 to permit a continuous weld 
of one hundred and eighty degrees. During the entire rotation of workpiece 
496 from the position of FIG. 9 to the position of FIG. 11, cam 60 and the 
components responsive thereto will cause the tip of welding torch 104 to 
be held at an optimum angle relative to the joint between the portions 498 
and 500. The overall result is that a smooth, continuous, well-formed 
three hundred and sixty degree weld will be provided at the joint between 
portions 498 and 500. 
Where both portions of a workpiece are right-circular cylinders, and where 
those portions are normal to each other, the profiles of cams 60, 406, and 
426 and 427 are relatively simple. As a result, a skilled and 
mathematically-oriented tool maker should be able to define those profiles 
by mathematical processes. However, if a tool maker is not 
mathematically-oriented, or if the portions of the workpiece are L-shaped, 
U-shaped or otherwise polygonal in cross section, it will usually be 
desirable to make actual measurements and then plot the profiles of the 
cams 60, 406, and 426 and 427. Specifically, the workpiece can be secured 
to a fixture similar to the fixture 490, that fixture and workpiece can be 
rotated, step by step, through the desired number of degrees of rotation, 
the welding torch 104 can be set, step by step, in the desired vertical, 
radial and torch-angle positions, and then precise measurements can be 
made of the radial distances between cam followers 170 and 422 and the 
axis of shaft 56 and of the radial distance from cam follower 412 and the 
axis of shaft 404. Those precise measurements can then be used in plotting 
the profiles of cam 60, 426 and 406. 
The downward and outward movement of the welding torch 104 from the 
position of FIG. 9 to the position of FIG. 10 requires simultaneous 
downward movement and counter clockwise rotation of beam 430. That 
downward movement is effected by "falls" on cams 426 and 427 which permit 
the weight of U-shaped bracket 418, beam 430, and of pivoted supports 442 
and 542 to force the cam followers 422 and 429 to follow those "falls". 
The outward movement of torch 104 is effected by a "rise" on cam 406 which 
forces cam follower 412 to rotate lever 410, and hence lever 450, pivot 
428, beam 430 and rotatable support 442, in the counter clockwise 
direction. The "falls" on cams 426 and 427 must be interrelated to the 
"rise" on cam 406 so the tip of the torch 104 maintains a predetermined 
distance from the joint between the portions 498 and 500. Also, the 
corresponding portion of the profile of the cam 60 must be interrelated to 
the "rise" on cam 406 and to the "falls" on cams 426 and 427 to keep the 
tip of the welding torch at an optimum torch angle. 
The downward and inward movement of the welding torch 104 from the position 
of FIG. 10 to the position of FIG. 11 requires simultaneous downward 
movement and clockwise rotation of beam 430. That downward movement is 
effected by continuing "falls" on cams 426 and 427 which permit the weight 
of U-shaped bracket 418, beam 430, and of the pivoted supports 442 and 542 
to force the cam followers 422 and 429 to follow those continuing "falls". 
The inward movement of torch 104 is effected by a "fall" on cam 404 which 
permits cylinder 458 to cause cam follower 412 to rotate lever 410, and 
hence lever 450, pivot 428, beam 430 and rotatable support 442 in the 
clockwise direction. The continuing "falls" on cams 426 and 427 must be 
interrelated to the "fall" on cam 406 so the tip of the torch 104 
maintains a predetermined distance from the joint between the portions 498 
and 500. Also, the corresponding profile of the cam 60 must be 
interrelated to the "fall" on cam 406 and to the continuing "falls" on 
cams 426 and 427 to keep the tip of the welding torch at an optimum torch 
angle. 
At the conclusion of the continuous three hundred and sixty degree weld, 
the motor 236 will be reversed, and it will rotate the fixture 490 and the 
workpiece 496 back to the position shown by FIG. 9. As that fixture so 
rotates, the cylinder 458 will again act through piston 460, lever 450, 
pivot 428, beam 430, and pivoted support 442 to hold the welding torch 104 
away from the workpiece 496. While the fixture 490 is in the position 
corresponding to FIG. 9, the welded workpiece 496 can be removed, and the 
portions of a further workpiece can be secured to that fixture. 
It will be noted that the axis of cam follower 412 is confined for 
substantially straight-line horizontal movement. This is due to the fact 
that lever 410 is long, rotates around fixed pivot 408, and always is 
close to vertical. Consequently, even though the lever 450 can be moved 
vertically a distance equal to twice the product obtained by multiplying 
the radius of the concentrically-rotated workpiece by seventy thousand 
seven hundred and eleven millionths (0.70711)--the sine of forty-five 
degrees--the vertical position of cam follower 412 will remain 
substantially constant. Even if the maximum radial difference between the 
highest and lowest "dwells" on cam 406 was a full inch, and even if all of 
the resulting rotation of lever 410 was away from vertical, the maximum 
change which that rotation could produce in the vertical position of cam 
follower 412 would be just slightly more than two hundredths (0.02) of an 
inch if the lever 410 was twenty-four (24) inches long. Even if that lever 
was only fourteen (14) inches long, and even if the maximum radial 
difference between the highest and lowest "dwells" on cam 406 was a full 
inch, the maximum change which rotation of lever 410 could produce in the 
vertical position of cam follower 412 would be less than four hundredths 
(0.04) of an inch. In contrast, the upper end of the lever 450 must move 
seventy thousand seven hundred and eleven millionths (0.70711) of an inch 
when the portion 500 of workpiece 496 has a diameter of one inch. 
If the cam follower 412 were to be mounted so it moved vertically with the 
lever 450, that movement would materially complicate the task of defining 
the profile of cam 406; because that movement would cause that cam 
follower to engage that cam profile at different vertical levels. The cam 
406 is essentially a circular disc with "rises" and "falls" thereon; and 
hence a change in the level of the point of engagement between cam 
follower 412 and that cam would almost certainly produce a sideways 
movement of that cam follower--unless the profile of that cam was 
specially modified to prevent any sideways movement. 
The serious nature of the problem which could arise if cam follower 412 
were to move vertically with lever 450 is well illustrated by the 
following assumed conditions: (1) the normal, unrelieved diameter of cam 
406 is five inches, (2) the diameter of tubular member 500 is one inch, 
and (3) cam follower 412 engages cam 406 at the level of the axis of shaft 
404 when lever 450 is in its uppermost position. Under those assumed 
conditions, the cam 406 should move cam follower 412 one hundred and 
forty-six thousandths (0.146) of an inch to the left from the position of 
FIG. 9 to the position of FIG. 10, and should then move that cam follower 
an equal distance to the right from the position of FIG. 10 to the 
position of FIG. 11. However, the seventy thousand seven hundred and 
eleven millionths (0.70711) of an inch of downward movement, which lever 
450 would impart to cam follower 412, would cause that cam follower to 
shift to the right a distance of one hundred and two thousandths (0.102) 
of an inch--a distance which is sixty-nine percent (69%) of the Radial 
Motion Control distance required by FIG. 8. Also, because that undesired 
right-hand sideways movement would occur in part while cam follower 412 
was supposed to be moving to the left, that right-hand movement would 
seriously complicate the problem of defining the profile of cam 406. 
The mounting of the cam follower on lever 410, which is held against 
vertical movement, which is long, and which is always close to vertical so 
limits the vertical range of points at which cam follower 412 can engage 
cam 406 that the profile of cam 406 does not need to include any 
compensation for undesired sideways movement of that cam follower. In fact 
the profile of cam 406 would not need to include any compensation for 
undesired sideways movement of cam follower 412 even if the welding 
machine were to be built so it was large enough to accommodate 
continuously-rotated workpieces of many inches in diameter. 
Where the welding machine is to be used with a workpiece which can be 
rotated through three hundred and sixty degrees, it will neither be 
necessary nor desirable for the beam 430 to be moved vertically. In such 
event, the lever 480, and its counterpart adjacent enclosure 48, will be 
rotated from the solid-line position to the dotted-line position of FIG. 
4. Thereafter, the cam 476, and its counterpart adjacent enclosure 48, 
will hold the U-shaped bracket 418, and hence the beam 430 and the pivoted 
supports 442 and 542, at a fixed level. 
Referring particularly to FIGS. 12-16, the numerals 32,34, 45, 50, 44, 56, 
58 and 60 denote a bend, a flat portion, an opening, feet, an enclosure, a 
shaft, a sprocket gear and a cam which are identical to the 
identically-numbered corresponding bend, flat portion, opening, feet, 
enclosure, shaft, sprocket gear and cam in FIGS. 1-7 and in the patented 
welder. Also, the numerals 154, 170, 188, 200 and 202 denote an arm, a cam 
follower, an adjustable-length link, a shaft and a sprocket gear which are 
identical to the identically-numbered corresponding arm, cam follower, 
adjustable-length link, shaft and sprocket gear therein. 
The numeral 528 denotes an elongated pivot which extends through a hollow 
elongated beam 530; and that pivot and that beam preferably will be 
essentially identical to pivot 428 and beam 430 of FIGS. 1-7. The numeral 
540 denotes shouldered screws which extend downwardly and upwardly through 
forwardly-extending plates on the deep forward portion of an elongated 
arcuate pivoted support 552 to seat within sockets in a U-shaped bracket 
550. The pivoted support 552 and the bracket 550 will preferably be 
essentially identical to the pivoted support 442 and bracket 432 of FIGS. 
1-7. Retainer plates 574 are provided at the rear of U-shaped bracket 550 
to hold that bracket in assembled relation with the beam 530; and 
fasteners 576 secure those retainer plates to that bracket. The shouldered 
screws 540, and the spacing of the front edge 553 of the pivoted support 
552 rearwardly of the bracket 550, permit that pivoted support to rotate 
relative to that bracket, and hence relative to the beam 530. 
The numeral 560 in FIGS. 12-16 denote ears which are fixedly mounted on the 
inner wall of enclosure 44; and those ears extend into the space between 
that enclosure and enclosure 48. Similar ears, not shown, are fixedly 
mounted on the inner wall of enclosure 48; and those ears extend into the 
space between that enclosure and enclosure 44. A bracket 562, with an 
upper arm 564 and a lower arm 566, is pivotally secured to the ears 560 by 
a rod 558 that is secured within openings in those arms. That rod is held 
for vertical movement by the ears 560 to permit upward and downward 
movement of the bracket 562. A similar bracket and rod, not shown, are 
provided adjacent the enclosure 48. The bracket 562 and its counterpart 
have openings 572 therein through which the pivot 528 extends to enable 
those brackets to support that pivot and the beam 530. 
A pivot bracket 568 is provided at the lower face of the lower arm 566 of 
bracket 562, as indicated particularly by FIG. 15. That bracket rotatably 
supports a roller 570 which bears against, and which is a follower for, a 
cam 592 that is mounted on the shaft 56. A similar cam follower and a 
similar cam are provided adjacent enclosure 48. "Rises" and "falls" on 
those cams will effect upward and downward movement of those cam 
followers, and hence of bracket 562 and its counterpart, pivot 528 and 
beam 530. 
The numeral 580 denotes a pivot which extends from the inner wall of 
enclosure 44 a short distance toward enclosure 48, as shown particularly 
by FIGS. 14 and 16. An elongated arm 582, with an upward extension 584 at 
the right-hand end thereof, is pivotally held by pivot 580; and that 
upward extension is in register with the bottom of the lower arm 566 of 
bracket 562, as indicated particularly by FIGS. 15 and 16. The numeral 586 
denotes a pivot which extends a short distance from the inner wall of the 
enclosure 44 toward enclosure 48; and that pivot is located below the 
level of the left-hand end of arm 582, as that arm is viewed in FIGS. 15 
and 16. A latch 588 is rotatably mounted on the pivot 586; and a helical 
extension spring 590 biases that latch for rotation in the clockwise 
direction toward the left-hand end of arm 582. A stop, not shown, limits 
clockwise rotation of the arm 582 to the horizontal position shown by FIG. 
12, but will permit that arm to rotate in the counterclockwise direction 
to the position of FIG. 15. In the latter position, the extension 584 
engages the plate 566 of bracket 562, and thereby holds cam follower 570 
upwardly out of the path of the highest "rise" or "dwell" on cam 592, as 
indicated by FIG. 15. When the arm 582 is rotated to the position of FIG. 
15, the latch 588 can be rotated into position to hold that arm in that 
position; and, thereafter, until that latch is released, the spring 590 
will hold that latch in holding position. Further pivots 580 and 586, a 
further arm 582, and a further spring 590 will be disposed close to the 
inner wall of enclosure 48. As a result, both ends of the beam 530 can be 
raised upwardly and then held against vertical movement by appropriate 
rotation of the arms 582 and by the latching of latches 588. 
The numeral 600 denotes a hub on the lower end of an elongated, straight 
lever 602; and that hub is suitably fixed to the pivot 528 by a key, set 
screw or pin. The upper end of that lever has a roller 604 rotatably 
secured thereto by a pivot 606; and that roller engages, and will serve as 
a follower for, a cam 620 which is generally similar to cam 406 in FIG. 2. 
A shaft 622, which is comparable to shaft 404 of FIG. 2, supports cam 620, 
and also supports a sprocket gear 624. A sprocket chain 626 engages 
sprocket gear 624, sprocket gear 58, sprocket gear 202, and a sprocket 
gear, not shown, which is comparable to the sprocket gear 234 in FIG. 2. 
A pivot bracket 608 is provided at the upper portion of the inner surface 
of the front wall of enclosure 44, as shown particularly by FIG. 12; and a 
pivot 610 rotatably secures a pneumatic cylinder 612 to that pivot 
bracket. The piston 614 of that cylinder has a clevis-like end 616 that 
telescopes over an intermediate portion of lever 602 and is pivotally 
connected to that portion by a pin 618. 
The structure in FIGS. 12-16 performs the same functions which the 
structure in FIGS. 1-7 performs. However, the structure in FIGS. 12-16 
confines the beam 530 for precisely vertical movement, whereas the beam 
430 in FIGS. 1-7 moves along an arcuate path as it is moved upwardly and 
downwardly. Because the distance between pivot 414 and pivot 428 in FIGS. 
2 and 4 is very much greater than the maximum vertical movement of beam 
430, that beam will follow an arcuate path which is so shallow that it 
resembles a straight line; and hence no modification of the "rises" and 
"falls" on cam 406 is needed to compensate for the non-linear movement of 
pivot 428, and beam 430 as they are raised and lowered. However, if the 
welding machine of the present invention were to be made large enough to 
weld devices which were very large in cross section, the arm 416, and its 
counterpart, of the U-shaped bracket 418 would have to be made unduly long 
to keep the arcuate path followed by pivot 428 shallow enough to resemble 
a straight line. In such event, the linear movement of beam 530 would be 
desirable. 
The lever 602, and hence the cam follower 604, will move vertically as the 
beam 530 is moved vertically; and, in that respect, the structure of FIGS. 
12-16 is not as desirable as the structure of FIGS. 1-7. However, the 
increased difficulties in designing the profile of cam 620, which 
inherently results from the vertical movement of lever 602 and of cam 
follower 604 with beam 530, can be lessened by providing a large diameter 
for that cam and also by disposing that cam follower a predetermined 
distance below the level of shaft 622 whenever beam 530 is in its 
lowermost position and by disposing that cam follower an equal distance 
above the level of that shaft whenever that beam is in its uppermost 
position. With such an arrangement, and by using great care, a profile for 
cam 620 can be developed which, together with carefully-developed profiles 
for cam 60 and cam 592 and its counterpart, will enable the tip of the 
welding torch 104 to closely "track" the joint to be welded. 
It would be possible to use the structure of FIGS. 12-16 even if the upper 
and lower ends of the vertical path of movement of cam follower 604 were 
not disposed equal distances from the level of the axis of cam 620. 
However, if the upper and lower ends of the vertical path of movement of 
that cam follower were disposed equal distances from the level of the 
seven thirty o'clock point on cam 620, it would be very difficult to 
develop a properly-compensated profile for that cam. For example, if it 
were assumed that cam 620 had a normal, unrelieved diameter of five inches 
and that the portion 500 of workpiece 596 had a diameter of one inch, the 
cam follower 604 would have to move horizontally only slightly more than 
one hundred and forty-six thousandths (0.146) of an inch from the position 
of FIG. 9 to the position of FIG. 10 and then move that same distance back 
to the position of FIG. 11, but that cam follower would move almost six 
hundred and thirty thousandths (0.630) of an inch horizontally as the beam 
530 moved that cam follower less than three hundred and fifty-four 
thousandths (0.354) of an inch above and below the level of the seven 
thirty o'clock point on cam 620. As a result, a toolmaker would have great 
difficulty in developing a cam profile which was intended to provide a 
desired "rise" of only slightly more than one hundred and forty-six 
thousandths (0.146) of an inch but which had to prevent a much 
greater--almost six hundred and thirty thousandths (0.630) of an 
inch--incipient horizontal movement due to the vertical movement of beam 
530. That toolmaker would have considerable difficulty in developing a cam 
profile for cam 406 in FIG. 2 if the cam follower 412 were to be mounted 
on an upward extension of lever 450, and hence moved vertically as the 
beam 430 was moved vertically. 
The structure shown in FIGS. 1-7 is preferred where the diameter of the 
concentrically rotated portion of the workpiece is less than three inches. 
For workpieces having larger concentrically rotated portions, the optimum 
structure would use the linear-movement mounting of FIGS. 12-16 for the 
beam, but would use the beam-tilting lever system of FIGS. 1-7. Such a 
structure could be made large enough to weld concentrically rotated 
portions of very large cross sections without any need of compensating for 
vertical movement of cam follower 412 or for non-linear vertical movement 
of beam 430. 
FIGS. 8-11 indicate how a continuous three hundred and sixty degree weld 
can be provided by rotating a workpiece two hundred and seventy degrees 
and by moving a welding torch through a composite vertical path that 
corresponded to ninety degrees of rotation of that workpiece. If desired, 
however, the workpiece could be rotated as few as two hundred and forty 
degrees or could be rotated as many degrees as the configuration of the 
workpiece permits; and the composite vertical path for the torch could be 
made to correspond to as many as one hundred and twenty degrees of 
rotation of that workpiece or to any lesser desired number of degrees of 
that rotation. 
If the operator of the welding machine of the present invention wished to 
provide a continuous weld of more than three hundred and sixty degrees--to 
make absolutely certain that no tiny air gap had formed between the 
beginning and end of that weld--and if the workpiece could not be rotated 
more than three hundred and sixty degrees, the workpiece would be rotated 
through an angle which would coact with the composite vertical movement of 
the welding torch to provide the desired angular extent of more than three 
hundred and sixty degrees for the weld. If that operator desired a 
continuous weld which had an angular extent that was substantially smaller 
than three hundred and sixty degrees but was larger than the angular 
rotation of the workpiece, the composite vertical movement of the welding 
torch would provide the relative movement between the welding torch and 
that workpiece which would provide the desired angular extent for the 
weld. It thus should be apparent that the welding machines provided by the 
present invention do not impose any top limit on the angular extent of 
continuous welds, and do not even impose limits on the angular extents of 
rotation of workpieces. Instead, any limits on the extents of rotation of 
those workpieces are imposed by the configurations of those workpieces, 
and continuous welds of greater angular extends can be provided by the 
composite vertical movement of the welding torch. As a result, it should 
be apparent that the present invention provides a method and structure for 
making continuous welds which have angular extents that are greater than 
the angular rotation of the workpieces. 
In the embodiments of welding machine shown by the drawing, the cam 
followers 412 and 604 are, respectively, disposed at the left-hand sides 
of cams 406 and 620; and such dispositions are very useful. If desired, 
however, those cam followers could, by use of different lever systems 
therefor, be disposed at the tops, bottoms or right-hand sides of those 
cams. The most important consideration in mounting those cam followers 
adjacent those cams is that all movement of those cam followers, in a 
direction transverse of the desired movement in response to "rises" and 
"falls" on those cams, be kept small. In that sense, the arrangement shown 
in FIGS. 1-7 is ideal; because the fixed pivot 408 for lever 410 
substantially prevents any movement of cam follower 412 in a direction 
which is transverse of the desired movement of cam follower 412 radially 
relative to cam 406. In that sense, the arrangement shown in FIGS. 12-16 
is not ideal; but it is far better than an arrangement where the cam 
follower 604 would be disposed at the seven thirty o'clock position on cam 
620, and hence would be displaced forty-five degrees from the point on the 
periphery of that cam wherein the cam follower could move radially 
relative to that cam. 
It will be noted that the horizontal movement of pin 468, and hence of 
connecting rod 466, will be less than the horizontal movement of cam 
follower 412. Similarly, the horizontal movement of pin 470 will be less 
than the horizontal movement of cam follower 412. However, the horizontal 
movement of cam follower 412, which is needed to provide the desired 
horizontal movement of welding torch 104, is readily determined. 
Whereas the drawing and accompanying description have shown and described a 
preferred embodiment and an alternate embodiment of the present invention, 
it should be apparent to those skilled in the art that various changes may 
be made in the form of the invention without affecting the scope thereof.