Rotary welding device

A welding device for building up metal for repair or construction of a metal bores, outside diameters and circular faces by laying down single or continuous metal weld beads in a pre-selected pattern; including a base member to receive a rotatable table with a drive is provided on the base to rotate the table at selected speeds. An elongated tubular spindle is provided to rotate with the table. Conduits for welding wire, welding current (power) and a shielding gas supply is provided to the spindle to supply gas, power and wire to the area adjacent the point of exit of the wire. The tip of the spindle serves as one electrode contactor in a welding process and the metal to be welded serves as the other. The spindle rotates with movement of the rotating table where the table includes a horizontal guide member to receive a slide member which carries the spindle and the slide member is longitudinally moveable in the guide to be selectively advanced and retracted by a variable horizontal feed device also located on the rotating table and where the rotatable table further includes a rotatable threaded connecting member to receive the spindle where the outside of the spindle is threaded so that upon rotation of the connecting member the spindle is raised and lowered relative to the rotating table.

BACKGROUND OF THE INVENTION 
The present invention relates to devices for laying down a continuous bead 
of weld overlay material in a selected pattern on a metal base. Devices 
within the scope of the present invention find particular application as 
semi-automatic and automatic welding machines used for overlay welding of 
new metal for the repair of oversize or worn bores, undersize trunnions 
and worn faces of mechanical equipment. 
Devices within the scope of the present invention are designed principally 
for welding in an indexed repetitive pattern for example a helix, 
continuous spiral flat mode, or adjacent straight weld beads and at angles 
in an included range of a vertical to horizontal postion. Likewise, in 
addition to continuous welding, devices within the scope of the present 
invention can be adapted to perform incremental welding. 
While the method and apparatus of the present invention are useful in many 
applications, the method and apparatus is particularly useful in the 
repair of enlarged interal bores or worn outer cylindrical surfaces. For 
example, in the repair of oversize bores where the bore receives a pin and 
acts as a pivot, the bore wears internally so the diameter becomes too 
large to permit satisfactory operation of the equipment. Another example 
is the inside and outside diameters of cylinder walls and trunnions on 
hydraulic and other mechanical devices where a piston, cylinder or shaft 
causes wear. In such instances the prior art has generally utilized 
sleeving as a means of repair. However it has been found that in many 
instances the sleeves "coin" and fall out of the bore after a short period 
of reuse. 
Additionally the present invention provides method and apparatus useful in 
overlay welding construction, for example where a carbon steel base is 
overlaid with another metal such as stainless steel. 
The present invention provides means to replace the worn metal with metal 
of characteristics at least equal to the original and permits remachining 
of the bore substantially as it was originally. 
No prior art device is known for accomplishing the objectives of the 
present invention for repairing bores, trunnions or/and faces, by overlay 
welding in a semi-automatic or automatic mode on a continuous or 
incremental basis in the same means as the present invention. 
With the exception of robotic controlled welding (where no prior art device 
is known which provides means for a buildup of metal in long length bores) 
the prior art provides a fixed welding head and the use of rotatable 
welding positioners and manipulators utilized as a cooperative pairs where 
the devices are used in tandem to position and move the element to be 
welded as opposed to rotation of the welding heads as provided by device 
in accordance with the present invention. In such prior art arrangements 
the positioner holds and turns the work piece while the manipulator or 
welder holds and manipulates the welding torch. Present day equipment is 
limited by the size of the part being welded and requires parts that can 
be readily clamped and centered on a positioner. If the part is too large 
for the positioner a different arrangement must be utilized. 
Additional problems are encountered in the prior art, in that balancing the 
work piece on the weld positioner is necessary to ensure proper welding 
speed and the overhanging weight of the part must not exceed the capacity 
of the positioner. 
No prior art device is known which permits continuous repetitive indexed 
feed of an incremental welding bead inside or outside of cylindrical 
shapes or continuous spiral feed welding on flat surface, while the work 
piece doesn't move. Prior art equipment further cannot be used to perform 
incremental welding of bores that are unevenly enlarged or out of round 
due to excessive wear. 
Two known prior art devices illustrated in FIG. 1A and 1B the accompanying 
drawings are manufactured respectively by the C. C. Peck Company of 
Cleveland, Ohio and the Bancroft Corporation of Waukesha, Wis., to provide 
means for welding but both have the welding head and the part exposed at 
an angle with respect to one another and the welding heads cannot be 
rotated through more than 360.degree. nor can the heads be laterally 
advanced and retracted. 
The prior art further includes various patents which relate to rotatable 
type welding equipment but none of which teach the features of the present 
invention. The references include Valentine, U.S. Pat. No. 3,913,820; 
Yasenchak, U.S. Pat. No. 3,665,148; Mikulak, U.S. Pat. No. 2,749,421; 
Cooper, U.S. Pat. No. 3,543,989; Kemsure, U.S. Pat. No 4,131,783; and 
Massakihano, U.S. Pat. No. 3,709,423. 
SUMMARY OF THE INVENTION 
The present invention provides new and useful welding methods and 
arrangements which can be utilized in welding overlying new metal to 
existing base metals. In one example the method and apparatus of the 
present invention is utilized in gas metal arc welding such as a gas 
shielded arc welding processes in which the welding heat is obtained from 
an electric arc between a consumable electrode called a filler wire and a 
grounded work piece. The filler wire is melted in the inert gas atmosphere 
and is transfered to the work surface, the joint, or other welding area 
where it is desired to build up welding metal. The arc provides sufficient 
heat to fuse the filler wire and to alloy it with the work surface or the 
joint metal. The molten weld puddle is protected from the atmosphere 
during the welding operation by the gas, which is an inert gas, otherwise 
atmospheric oxygen and nitrogen would combine with the molten weld metal 
leaving the weld porous and weak. In general, a filler wire is utilized 
having physical properties at least equal to or stronger then the work 
piece so that the repaired area is not weakened. While the present 
invention is described herein with reference to the gas metal arc welding 
process the method and apparatus of the present invention are equally 
useful in other welding methods such as gas tungsten arc welding, and 
plasma arc welding or other welding processes and filler metals such as 
fluxcore and fabricated wires. Devices within the scope of the present 
invention are useful, in general, in over-laying metal surfaces to be 
repaired. The devices further can be utilized for filling wear spots in 
inside diameter bores, either continuously or incrementally, trunion 
welding, welding on outside diameter, either continuously or 
incrementally, face welding on the top, bottom or sides and in a spiral in 
and spiral out mode on top, bottom or sides. Single or multiple bead 
welding can be accomplished in the vertical or up/down mode inside or 
outside of bores or other geometric shapes. It will be understood that the 
present invention can be utilized to overlay metal in repair, or in new 
manufacture, and while the invention is described hereinafter in reference 
to inside welding of bores the invention is not limited thereto. 
Likewise single and multiple bead welding can be accomplished in vertical 
or up/down mode on the outside diameters of cylinders or other circular 
shapes as well as single bead welding on flat, angular, or radial surfaces 
or inside or outside or circular shapes. 
Further, devices within the scope of the present invention are portable so 
a positioner device is not required to hold the part to be repaired so the 
welding device can be moved to the repair sight to repair large pieces of 
equipment which would be difficult to move and, in many instances, too 
large to be placed on a positioner as required by the prior art. 
Briefly the present invention provides a welding device for building up 
metal for repair or construction of a metal bore by laying down a metal 
weld bead in a selected pattern; including a base member to receive a 
rotatable table with a drive is provided on the base to rotate the table 
at selected speeds. An elongated tubular spindle is provided to rotate 
with the table. Welding wire and a gas supply is provided to the spindle 
to supply gas and wire to the area adjacent the point of exit of the wire. 
The tip of the spindle which may be a consumable welding wire serves as 
one electrode in a welding process and the metal to be welded serves as 
the other. The spindle rotates with movement of the rotating table where 
the table includes a guide member to receive a slide member which carries 
the spindle and the slide member is longitudinally moveable in the guide 
and is on laterally moveable to be selectively advanced and retracted by a 
horizontal feed drive motor also located on the rotating table and where 
the rotatable table further includes a rotatable threaded connecting 
member to receive the spindle where the outside of the spindle is threaded 
so that upon rotation of the connecting member the spindle is raised and 
lowered relative to the rotating table. 
It will be understood that various arrangements within the scope of the 
present invention will occur to those skilled in the art upon reading the 
disclosure set forth hereinafter and that the disclosure setforth 
hereinafter with reference to accompanying drawings is not by way of 
limitations.

DETAILED DESCRIPTION OF THE DRAWINGS 
FIG. 1A is an illustration of one example of a prior art device 
manufactured by the C. C. Peck Company wherein a base 1 is provided which 
carries a drive 2 to raise and lower a bracket 3 which carries drive motor 
4 to rotate a welding column 6 in the directions shown by arrow A. Welding 
column 6 is provided with a wheel 5 which is connected to the column and 
rotated by a drive mechanism 4 connected to the bracket 3 to rotate the 
welding system. A reel 13 is provided to supply welding wire 9 to a feeder 
head 11 driven by a motor 8 to provide welding wire at a tip 12. A tube 15 
is provided as shown to supply inert gas. The welding assembly including 
column 6 which can be moved up and down in rapid traverse positioning only 
to facilitate loading and unloading of parts to be welded as indicated by 
arrow B by drive 2. The device as shown can only preform joint welding as 
shown in FIG. 4. Further the welding head cannot be advanced into the bore 
and no provision is made for lateral adjustment of position of the welding 
column 6 as provided in the present invention as described hereinafter. 
FIG. 1B is an illustration of a type of equipment manufactured by Bancroft 
Corp. where a stationary column 21 is provided having a wire feed spool 22 
to feed wire 20 to controller 24 which controls the operation of the 
device and likewise controls the rate of feed of the wire 20. Controller 
24 is mounted on a bracket 23 which is moved up and down in rapid traverse 
to facilitate loading and unloading of parts to be welded, as shown by 
arrow C by means of a hydraulic cylinder 26 where a welding assembly 
column 27 is provided from controller 24 extending downwardly to a welding 
head positioner 28 which holds an electrode feed device 29 above a plate 
30 where plate 30 can be rotated as indicated by arrow I to weld the work 
but the column cannot be moved laterally. 
FIG. 1C is an illustration in partially cut away perspective, of one 
arrangement within the scope of the present invention. 
A feed reel 31 is provided to feed wire 34 where reel 31 is carried on a 
bracket 40 which is connected to a column which carries a rotory joint 
shaft coupling 72. A fixed table 31 is provided and is carried by a radial 
arms 111 shown in FIG. 3. Column 37 can, for example be a thick walled 
steel supporting tube to provide support for the rotating assembly 
described hereinafter and can be provided with a hollow copper pipe buss 
37B and an inner conduit 35 to receive electrode wire 34 as shown in FIG. 
2. Inert gas, as described hereinafter with reference to FIG. 2, is 
supplied through annular passage 38 between buss 37B and conduit 35 from 
rotary coupling 72. A rotary table 32 is provided in an aperture 39 of 
table 31 where table 32 is carried by and rotated in, spaced rollers 41 
which support and guide a lip 42 of table 32 as shown. Table 32 can have a 
second lip 43 to pass thru aperture 39 as shown. 
A chain 48 secured to lip 43 is provided in sprocket teeth (not shown) 
around the periphery of table 32 where chain 48 is driven by a sprocket 52 
driven by a bidirectional drive motor 53 to rotate table 32 at selected 
speeds depending on the character of the material to be welded. The drive 
53 is located on the fixed table 31 and does not rotate with the rotary 
table 32. 
A cross slide 56 is provided to be received in guides 51 extending 
diametrically across table 32 adjacent an opening 45 in the center of 
table 32, as shown, to permit lateral movement of the slide which carries 
the welding assembly described herein. Column 37 is journaled on slide 56 
by means of a nut assembly (not shown) in head 57C which is operated by 
first and second sprockets 57A, 57B, where the nut assembly receives 
threaded surface 62 of shaft 37 to facilitate vertical movement of shaft 
37. Referring to FIG. 1C sprockets 57A, 57B, are of different diameters 
and receive chains 65, 66 driven by likewise different diameter sprockets 
68, 69 driven by a drive 60. The differential in the rate of rotation of 
the sprockets 57A, 57B because of the difference in diameter of the 
sprockets 57A, 57B and sprockets 68, 69 causes rotation the two sections 
of the nut assembly to raise and lower column 37 to cause vertical 
movement of the assembly at selected speed to provide a weld, of selected 
spacing in response to the direction of rotation as indicated by arrow D 
of FIG. 1C. Slide 56 which carries shaft 37 can also be moved 
bidirectionally as shown by arrow F by means of a lead screw 47 which is 
driven by drive 46 and engages a connecting nut (not shown) to move slide 
56 bidirectionally as desired as shown by arrow F in response to rotation 
of drive 46. Drive 46 is carried for rotation with table 32 so that the 
welding column 37 can be advanced or retracted in the directions shown by 
arrow F during the rotation of table 32. 
Referring again to FIG. 1C a wire feed drive 36 is provided to supply 
electrode wire 34 from reel 31 through tube 35 carried within column 37 to 
an outlet contact tip 37B, as shown in FIGS. 1C and 2. Referring again to 
FIG. 1C, the gas from inlet 50 of FIG. 1C flows through annular passage 
38, as shown in FIG. 2. Inlet tube 50 (FIG. 1C) can be connected column 37 
by a rotary joint 72 which allows inert welding gas to flow to the annular 
conduit 38 (FIG. 2) defined between buss shaft tube 35, and buss tube 37B, 
so that the gas is emitted adjacent the wire feed. Buss tube 37B also 
serves to conduct electrical power to contact tip 37B by means of 
electrical connector 50A (FIG. 1C) which is connected to a source of 
electrical power supply (not shown) to provide one electrode where the 
metal being welded serves as the electrode of opposite polarity. 
As previously described table 32 is driven by means of drive 53 which is 
carried on table 31 so that actuation of drive 53 rotates table 32 shown 
by arrow G for rotational movement and, where desired, multiple rotations 
not permitted by prior art or in a reciprocatory motion as described 
hereinafter to allow incremental welding. 
Operating power for the drive 60, which drives the vertical feed sprockets 
68-69, the drive 46 which drives the lead screw 47 for lateral movement of 
slide member 56, and drive 36 which supplies the feed wire, is supplied 
through a slip ring assembly 90, details of which are shown in FIG. 2. 
Connections 101, 97, 92 are supplied from variable direct current power 
supplies 102, 103, 104 as shown where the power supplies are carried by a 
bracket on permanent table 31 to the slip rings so that the current can be 
supplied to the drives previously described while they are rotating on 
table 32. 
In FIG. 2, the leads 92 and 97 are shown, in diametrically opposed 
relation, connected to brush assemblies 91 and 96 where, with reference to 
brush assembly 91, lead 92 is retained by a plastic insulating screw 94 
located therein and a brush 93 is supplied to contact a slip ring 89 which 
rotates with shaft 37. An identical arrangement is provided with respect 
to brush assembly 96 where a brush 96A is provided to contact a slip ring 
86. Slip rings 87 and 88 are also provided, slip rings 86 and 87 will be 
utilized to supply current to drive 36 and slip ring 88 and 89 will be 
utilized to operate drives 46 or 60 alternatively by means of switching 
from one to the other since they are not used simultaneously. It will be 
understood that brush assemblies similar to assemblies 91 and 96 are 
provided in the slip ring assembly 90 for power take offs to all drive 
members, previously described. As far as the assembly 90 is concerned in 
FIG. 2 shaft 37 is illustrated extending longitudinally there through with 
an internal copper buss tube 37B located inwardly therefrom defining an 
annular area 38 where the gas from rotating connecter 72, shown in FIG. 
1C, flows. Wire 34 is located internally of tube 35 and extends through 
the tube to the contact tip 37B where electrode wire 34 is emitted from 
tip 37B. 
With reference to FIG. 2, member 75 insulates the buss tube 37B from the 
grounded column 37. A similar insulator is located at the bottom column 
37. These insulators prevent electrical shortening of the welding power. 
A tubular housing member 79 and bronze bushing 77, control the shaft 37 
vertical guidance up and down. Feed nut (not shown) at the bottom located 
in FIG. 1C, 57C provides stability for shaft 37 at the bottom. Nut 78, 
retains electrical tubular sleeve insulators 85, insulator sleeve segments 
83, and copper slip rings 86, 87, 88, and 89. Nut 78 also provides a 
journal for bearing 82 and bearing retainer nut 80. Bearing 82 in turn 
provides a journal for outer stationary brush housing 81. Tubular housing 
member 79 is grooved vertically to allow electrical wires 92 and 97 that 
are soldered to slip rings 86, 87, 88 and 89 conducted from the top and 
bottom of 79. These wires provide electrical power to rotory drives 46, 60 
and 36. 
Assembly 90 is utilized to distribute power for operation of the drives 60, 
46 and 36 by means of slip rings while the table 32 is rotating to allow 
multiple turns of the welding column 37 to facilitate the overlapping and 
repetitive welding patterns described by the head 38 as described 
hereinafter. As shown in FIG. 1C power is distributed from slip ring 
assembly 90 to the drives, for example lead 97A which extends from slip 
ring assembly 90 to the wire feed assembly drive 36 illustrating that 
power input 97 from power supply 103 which operates the wire feed 36 (FIG. 
1C) is connected to the slip ring assembly 90 (FIG. 2). Also as shown 
conducter 92A extends from to slip ring assembly 90 drive 46 and 60 
alternatively where operation of drive 50 is controlled by power supply 
104. 
It will be understood that drive 53, 60, 46 and 36 can be operated by a 
programmable controller 105 which can be programmed to rotate table 32 at 
selected speeds or to cause table 32 to reciprocate in selected sequence 
for incremental welding. Additionally the controller 105 initiates and 
terminates welding power, as well as any shielding gas at precise and 
controlled intervals. 
FIG. 3 is an illustration of a bottom view of the assembly shown in FIG. 1C 
where the table 31 is shown carried by radial arms 111 extending outwardly 
from a base plate 112 which is carried by a column 113. The table 31 is 
retained by means of slide clamps 114 which can be provided with handles 
116 and a third slide clamp 117 provided on opposite arm 111 so that the 
table 31 can be moved radially with respect to arrow A and 
circumstantially with respect to column 113, arrow B for positioning where 
desired. The entire assembly affixed to member 112 can be mechanically 
raised or lowered for positioning to and desired height within the height 
of column 113. Rollers 41 are shown receiving the lip 42 of table 32 and, 
as shown, a limit switches 118 can be provided to be engaged by dogs 119 
carried in space relation on the underside of table 32. The dogs 119 can 
be used for incremental welding and can be spaced apart a distance equal 
generally to the arc of travel to be welded where sequential engagement of 
the dogs 119 with limit switch 118, is supplied to DC power supply 104 to 
cause reversal of drive member 53 and so that table 32 can oscillate back 
and forth along the arc of the area to be welded. Where desired, slide 
member 56 can be withdrawn or moved outwardly as the case may be depending 
on whether the welding is internal or external, to supply the overlaying 
layers of weld. Also, an electronic pulse counter can be used instead of 
dogs 119 and limit switches 118 if desired. 
A programmable controller (not shown) can be programmed to accomplish a 
selected task in automatic mode where the various drives 36, 46, 60 and 53 
are sequentially actuated to provide a weld, for example, of selected 
length, of selected number of overlaying layers, and of selected depth so 
that entirely automatic welding can be accomplished. The controls turn on 
and off the welding power, the wire feed, and the shielding gas. 
FIG. 4 is an illustration of one application of a device within the scope 
of the present invention where a nipple 121 is welded to a base 123 by 
means of an annular weld 124 which can be performed by a device within the 
scope of the present invention. 
FIG. 5 is an illustration of another arrangement where nipple 126 is welded 
to 127 by means of an internal weld 128 accomplished by a device within 
the scope of the present invention. A combination of weld joints, internal 
and external, may be accomplished if needed. 
FIG. 6A is an illustration of a tract 129 which is helical in nature and is 
demonstrative of the path which would be followed by the tip 38 of the 
welding device in welding a helical pattern inside a element 131 as shown 
in FIG. 6B where the element 131 is shown and the overlaying welds 132 are 
likewise illustrated. 
FIG. 7A illustrates the track 133 followed by the welding head 34 in making 
an external cylindrical weld on an element 134. The element 134 is shown 
in FIG. 7B as is the weld pattern 136. 
FIG. 8A is an illustration of the spiral pattern 137 which would be 
followed in overlaying weld surface on an element 138 where the element 
138 is shown in FIG. 8B and the weld 139 is likewise shown. 
In operation, the work piece setups are greatly simplified and setup time 
is greatly minimized. Unlike welding done on a prior art device where a 
postioner is utilized and the work piece must be clamped down and aligned 
with the axis of the postioner the devices within the scope of the present 
invention eliminate these steps, in that the work pieces do not have to be 
clamped down because the weight of the part is generally sufficient to 
retain the part because there is no force exerted on the part. Precise 
alignment of the work piece is not required since the device within the 
scope of the present invention, particularly where it is carried on radial 
arms 111 as previously described can be quickly aligned to the work piece. 
Further the parts which have been precluded from use on weld postioners 
because of size present no problem in use of devices within the scope of 
the present invention since the weight of the part does not affect or 
inhibit setup time since all of the parts to be worked on rest on the 
floor or the table. The welding accomplished by the device within the 
scope of the present invention can be accomplished principally in the 
automatic mode while welding utilized in prior art postioners are either 
manual or semi automatic and never automatic. 
Devices within the scope of the present invention are particularly useful 
to repair badly worn elongated holes where the holes normally wear in the 
direction of the load depart supports in service and the wear is generally 
never consistant from part to part. In order to restore the machining 
stock with weld filler more weld filler must be utilized on the portion of 
having the greatest wear. The incremental welding mode allowed by the 
present invention as previously described in combination with the 
subsequent use of full circle welding allows the operator to initiate 
welding in the area in most need of repair by incremental welding by use 
of the dogs 119 or pulse counters (not shown) previously described and 
then to extend the welding to the full circle for subsequent machining and 
repair. Further, each weld layed down by the device within the scope of 
the present invention in incremental mode because of the ability to move 
the welding head laterally, may be wider than the proceeding layer to 
ensure sufficient stock available when the bore is remachined to its 
correct location thus the width of the pad or increment of weld can be 
determined by the distance between the trip dogs or alternatively the 
teeth or the table drive chain can be counted by an inductive pulse 
counter switch and a programable computer 105 can be adapted to control 
the drive mechanism to regularly widen the area of the incremental weld. 
Thus the direction and width of the increment or pad can be determined by 
the location of the two trip dogs or the point on the machining table when 
counting of the chain lengths or sprocket teeth begins relative to the 
work piece. 
The welding sequence provided is that after alignment of the machine to the 
work piece center line the trip dogs are located manually or the counting 
sequence is set for the direction and width of the pad. Welding is then 
initiated at a line where the pad starts and the rotating table 32 turns 
with welding until it reaches the second trip dog, or a count of a given 
number of teeth on the rotary table depending upon which method is used. 
At this point the welding and rotary table stops and the upfeed controller 
102 indexs the column 37 an appropriate distance where the distance is 
determined by counting the teeth of the sprocket gear on the motor 60. The 
count is then fed back to the programmable controller 105 which has been 
preset for a given number of pulses or counts and when the count is 
reached the motors 60 is automatically turned off by the computer and 
initiates the welding by reversing the direction of the rotary table. In 
this method one bead of weld is laid down on top of each other all the way 
up the side of the wall of the bore until the operator turns off the 
machine. As the elongation of the bore is being rounded by progressively 
wider and wider pads the point is reached when one or more complete 
overlays of weld filler material is laid down on the entire bore without 
using the incremental features. 
A second arrangement within the scope of the present invention is 
illustrated in FIG. 9 where a wire spool 141 is provided to a column 145 
similar to column 37 of the arrangement of FIG. 1C. A wire 141A is 
provided to a feed device 144 which supplies the wire downwardly through 
the center of the column 145. A rotary connecter 146 is provided connected 
to a gas and power feed tube 147 to supply gas and power downwardly 
through the column as previously described. A vertical drive 148 is 
provided to drive pulleys 149, 150 which have different diameter as 
previously described with reference to the sprockets 69, 71, as 
illustrated in FIG. 1C. Cooperative sprockets 152, 157 are located on 
column 145 where chains 153, 154 are provided to be driven by sprockets 
149, 150 of drive 148 at different angular rotational speeds as previously 
described to operate feed nut assembly 166 similar to feed nut assembly of 
FIG. 1C to selectively raise and lower column 145. Also, a clutch assembly 
can be provided to engage one or the other of the sprockets 149, 150. 
Slip ring assembly 160 similar to slip ring assembly 90 is provided to 
receive and supply the power to the drives 148 and 144 as described with 
reference to Slip ring 90 of FIG. 1C, as shown in FIG. 9. A rotary drive 
motor 161 is provided to drive a sprocket 162 by means of a chain 163 as 
previously described with reference to FIG. 1C. The entire assembly is 
carried by an arm 175 which can be moved laterally and rotated about a 
pivot 191 as illustrated by arrows H and I to accomplish the objectives of 
locating the device. FIG. 10 is an elevational view, in section, of a 
portion of the arrangement shown in FIG. 9 where column 145 is shown as 
threaded. A segment of the slip ring assembly 160 is shown where 
electically conductive slip rings 176-179 are shown as is a brush assembly 
181 with a brush 182 to engage, for example, slip ring 176 all as 
previously described with reference to FIG. 1C and FIG. 2. A second brush 
assembly 183 is shown to illustrate that there are one brush for each slip 
ring, it being understood that only a portion of the assembly is shown. In 
the arrangement shown the brushes are enclosed in a protective box 184 to 
prevent electrical shocks and electrical shortcircuits. It will be 
understood that a tip assembly as shown in FIG. 1C can be provided where 
welding wire 141A extends outwardly. 
It will be understood that the foregoing are examples of devices within the 
scope of the present invention and that other arrangements also within the 
scope of the present invention will occur to those skilled in the art upon 
reading the disclosure set forth hereinbefore.