CA2485302A1 - Dual-process power cable with interchangeable tig welding torch and smaw electrode holder - Google Patents

Abstract

A power cable with interchangeable TIG torch and SMAW
electrode holder in which the heads can be interchanged quickly without tools and without the hazard of an exposed electrically hot male connector at the end of the cable. This is accomplished by providing a female receptacle at the head end of the power cable. The TIG torch and the SMAW electrode holder are each provided with the same type of male connector for coupling with the female receptacle on the head end of the power cable. The male connectors and the female receptacle may be of the twist-lock or similar variety. The provision of a single power cable with interchangeable heads for use in TIG
welding or SMAW reduces confusion at the worksite, reduces the cost of equipment, and increases flexibility in the welding operations.

Description

DUAL-PROCESS POWER CABLE WITH
INTERCHANGEABLE TIG WELDING
TORCH AND SMAW ELECTRODE HOLDER
BACKGROUND OF THE INVENTION
This invention generally relates to cables for supplying welding power from a power supply to a welding site. In particular, the invention relates to cables for supplying welding power to electrodes used in gas tungsten arc welding (GTAW) (also known as tungsten inert gas (TIG) welding) and shielded metal arc welding (SMAW) (also called "'Stick" welding).
Power supplies such as welding power supplies are used to provide high-amperage current. Typically, in a welding power supply, a pair of output terminals is provided. A welding cable connected to the welding torch (or stinger, drive assembly or welding circuit) is inserted into one of the two output terminals. The other output terminal receives a welding cable that is connected to the workpiece being welded. In some systems, the connectors are twist-lock type connectors (also called "international connectors"), the power supply has a female connector, and the welding cable has a mating male connector. In other systems, the cable has a female connector and the power supply a male connector.
In a conventions! TIG welding process, a concentrated high-temperature arc is drawn between a non-consumable tungsten electrode and a workpiece. The workpiece is connected to the output of a welding power source via a work clamp. The tungsten electrode is nested in a torch that comprises a shielding gas source, such as a cup, to direct a shielding gas, such as argon, helium, a mixture thereof, or other inert or non-inert gases, to a welding site on the workpiece. The torch receives a flow of shielding gas from a gas cylinder.
In accordance with known techniques, the welder may strike an arc by touching or scratching the electrode against the workpiece to close a circuit between the electrode and the work clamp. As the electrode is drawn away from the workpiece, an arc is initiated. Alternatively, the arc is initiated using a high-frequency electrical impulse provided by the welding power supply, which jumps to the workpiece. The welder then feeds a bare welding rod to the welding site. More precisely, the tip of the welding rod is inserted into the gap between the electrode tip and the welding site. The arc that crosses the gap from the electrode tip to the workpiece causes the tip of the welding rod and the underlying workpiece material at the welding site to melt, thereby creating a molten puddle. During a single welding pass, the arc and the welding rod must be moved in unison in order to. effect a weld bead. The displaced arc leaves the molten puddle in its wake. The portion of the molten puddle furthest from the 90 arc hardens continuously to leave a weld bead joining two pieces of metal.
When welding with the TIG process, the majority of heat goes into the arc, however a significant amount is retained in the torch.
Typically, means are provided for removing the wasted heat. Torches for GTAW welding may be either water- or air cooled. High-production or high-amperage torches are. usually water-cooled, while lighter-duty torches for low-amperage applications may be air-cooled.
The SMAW process d'rffers from the GTAW process in several fundamental respects. First and foremost, a consumable electrode is used.
Typically the electrode consists of a core of mild steel wire or other known material and a sheath surrounding the core and comprising a special coating that assists in creating the arc and at the same time produces a shielding atmosphere that protects the molten steel as it transfers across the arc. The consumable electrode is typically held between a pair of jaws made of electrically conductive material and electrically coupled to the power cable.
When no more of the electrode held by the jaws can be consumed, it must be replaced by a new consumable electrode. Another difference is that the SMAW
electrode holder does not need to be cooled. Also, shielding gas need not be soun;ed from the power supply unit in the SMAW process.
The greatest advantage of the GTAW process is that it will weld more kinds of metals and metal alloys than any other arc welding process.

GTAW can also weld dissimilar metals to one another, such as copper to brass and stainless steel to mild steel. The concentrated nature of the GTAW arc permits pinpoint control of heat input to the workpiece, resulting in a nan-ow heat-affected zone. There is no requirement for flux with this process.
Therefore, there is no slag to obscure the welder's vision of the molten weld pool. Also, in the GTAW process there is no transfer of metal across the arc.
Thus there are no molten globules of spatter (as in SMAW) to contend with.
The process itself does not produce smoke or injurious fumes.
The main disadvantage of the GTAW process is the iow filler metal deposition rate. Another disadvantage is that the hand-eye coordination necessary to accomplish the weld is difficult to team, and requires a great deaf of practice to become proficient. In contrast, in SMAW the electrode melts and becomes filler metal Also, the arc rays produced by the GTAW process tend to be brighter than those produced by SMAW. When welding in confined areas, concentrations of shielding gas may build up and displace oxygen.
In practice, a TIG welding torch is connected to a main unit that supplies power, shielding gas and coolant (if required) by means of a cable that comprises an electrical conductor, a channel for shielding gas, and in the case of a water-cooled torch, outbound and return channels for recirculating cooling water. In the case of an air-cooled torch, the water channels can be eliminated and the shielding gas can also be used for cooling the torch. In the case of Stick welding, the SMAW electrode holder is connected to the main unit via a power cable. It is known to provide different cables that are dedicated for use with a TIG torch or with a SMAW electrode holder respectively.
It is also known to provide a dual-purpose cable that can be used with either a TIG torch or a SMAW electrode holder, the torch and electrode holder being interchangeable. However, in this known combination torch setup, the cable has a threaded male connection. The amount of time needed to change the welding head becomes excessive because of this threaded connection, which requires the installed head to be unscrewed and the new head to be screwed, each operation requiring multiple turns. The known arrangement also has the disadvantage that it allows an electrically hot connector to be exposed during changing of the welding head, potentially creating a safety hazard.
There is a need for a power cable with interchangeable TIG torch and SMAW electrode holder that overcomes the aforementioned problems.
BRIEF DESCRIPTION OF THE INVENTION
The invention is directed to a power cable with interchangeable TIG torch and SMAW electrode holder in which the heads can be interchanged quickly without tools and without the hazard of an exposed electrically hot male connector at the end of the cable. This is accomplished by providing a female receptacle at the head end of the power cable. The TIG torch and the SMAW
electrode holder are each provided with the same type of male connector for coupling with the female receptacle on the head end of the power cable. The male connectors and the female receptacle may be of the twist-lock or similar variety. The provision of a single power cable with interchangeable heads for use in TIG welding or SMAW reduces confusion at the worksite, reduces the cost of equipment, and increases flexibility in the welding operations.
One aspect of the invention is a kit comprising: a power cable comprising a female receptacle at a head end; a TIG welding torch comprising a first plug that can be coupled in the female receptacle of the power cable;
and a SMAW electrode holder comprising a second plug that can be coupled in the female receptacle of the power cable.
Another aspect of the invention is a kit comprising: a power cable comprising a female receptacle at a head end; a T1G welding torch comprising a first male connector that can be coupled in the female receptacle of the power cable; and a SMAW electrode holder comprising a second male connector that can be coupled in the female receptacle of the power cable. The female receptacle is not threadably engaged with the portion of the first or second male connector inserted therein.
A further aspect of the invention is an assembly comprising: a power cable comprising an electrical conductor running the length of the power cable, a first electrical connector at a head end of the power cable and a second electrical connector at the other end of the power cable, and further comprising a channel running along the length of the power cable, the channel being at least partially occupied by a gas; and a SMAW electrode holder comprising a third elect~cal connector coupled to the first electrical connector of the power cable.
Yet another aspect of the invention is a method for changing the welding mode of a welding system: comprising the following steps: uncoupling a first welding head from a head end of a power cable by a relative movement different than unscrewing; and coupling a second welding head from the head end of the power cable by a relative movement different than screwing, wherein one of the first and second welding heads is a TIG welding torch and the other of the first and second welding heads is a SMAW electrode holder.
Other aspects of the invention are disclosed and claimed below.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a drawing showing a partially sectioned view of a known TIG welding torch.
FIG. 2 is a drawing showing an exploded view of a TIG
torch/power cable assembly in accordance with one embodiment of the present invention.
FIG. 3 is a drawing showing the TIG torch/power cable assembly of FIG. 2.
FIG. 4 is a drawing showing a partially sectioned view of the skeleton of the torch body depicted in FIG. 2.

FIG. 5 is a drawing showing a side view of the torch body depicted in FIG. 2.
FIG. 6 is a drawing showing a side view of a nipple with female receptacle incorporated in the power cable depicted in FIG. 2.
FIG. 7 is a drawing showing a side view of the power cable handle shown on a smaller scale in FIG. 2.
FIG. 8 is a drawing showing a side view of a SMAW electrode holder that can be interchanged with the TIG torch depicted in F1G. 3.
FIGS. 9 and 10 are drawings showing side and end views respectively of a handle for the SMAW electrode holder shown in FIG. 8.
Reference will now be made to the drawings in which similar elements in different drawings bear the same reference numerals.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with one embodiment of the invention, a welding system is provided wherein a TIG welding torch and a SMAW electrode holder can be interchangeably connected to a welding power supply unit via the same power cable. The single cable is capable of carrying cun-ent for either TIG or Stick welding processes. This single lead also carries shielding gas to the work site for TIG welding. This lead incorporates a female connection at the work site, allowing the operator to interchange a Stick electrode holder and a TIG
torch. The Stick electrode holder and TIG torch each incorporate a male connector that mates with the female connector in the power cable. These heads can be easily interchanged without the use of tools.
A known air-cooled TIG welding torch is depicted in FIG. 1. The torch comprises a torch head section and torch handle section. The head section comprises an internally threaded barrel 2 formed of copper or other highly electricailyconductive metal or alloy for retaining a tungsten electrode 4.

The electrode 4 is coaxially supported with respect to barrel 2 by means of a collet 6 formed by a tubular inner sleeve having longitudinal slots that define spring fingers that clamp onto the electrode 4. The collet 6 is in turn inserted within a collet body 8. The externally threaded rear end of collet body 8 is received within the lower forward end of barrel 2. The collet body 8 further comprises a nose projection 10 having multiple apertures 12 (only one of which is visible in FIG. 1 ) for emitting shielding gas introduced into the space between collet 6 and collet body 8.
The forward end of collet body 8 adjacent nose 10 is externally threaded to engage an internally threaded nozzle 14 formed of a temperature-resistant ceramic material. The shielding gas emanates from apertures 12 in the nose 10 of the collet body 8 and flows through the nozzle 14 to envelop the welding zone. The rearward end of nozzle 14 is tapered to nest within a front insulating collar 16 that is snapped onto the forward end of a cylindrical insulating jacket 18 that surrounds the barrel 2. The jacket 18 is molded of an elastomeric material. A back insulating collar 20 snaps onto the rearward end of the jacket 18. A tubular stem 22 of a back cap 24, in which the rear portion of electrode 4 is disposed, extends through the back insulating collar 20 and threadably engages the rear end of the barrel 2. An O-ring seal 26 is disposed between the back insulating collar 20 and the back cap 24.
The barrel 2 of the torch head section is joined to the handle section by means of a tube 28 made of a highly electrically conductive metal or alloy. The end of the tube 28 is connected to barrel 2 and extends laterally therefrom at an oblique angle relative thereto. A cylindrical connector 30 made of an electrically conductive material is connected onto the rearward end of tube 28 for connecting the torch to a source of welding current as welt as to a pressurized source of shielding gas. The connector 30 in its forward end has an internal bore 32 equal in diameter to the internal diameter of tube 28. The rear portion of connector 30 has a bore 34 of larger diameter, which is internally threaded to accommodate a conventional externally threaded coupler 36 on the head end of a power cable 38. Shielding gas flows in series through a channel inside the cable 38; through the bores of the coupler 36, the connector 30 and the tube 28; into the annular space between the barrel 2 and the collet 6;
through the space inside the collet body 8; and out the apertures 12 in the nose 10 of the collet body 8.
A cylindrical body 40, made of an elastomeric insulating material such as silicone rubber, is molded over and around the tube 28. In fabricating the torch body, the barrel 2 and tube 28 are placed in a mold into which a silicone rubber molding compound is injected to form the molded body 40, which body also surrounds the barrel 2 to define jacket 18. The mold is designed to form suitable flanges at the opposite ends of the jacket for mounting the front and back insulating collars. The mold is also designed to form a shoulder 42 and a plurality of spaced annular ribs 44 to the rear of the shoulder 42. The ribbed section of the molded body is disposed within a tubular handle 46 made of electrically insulative material. The fonnrard end of handle abuts shoulder 42. The electrically insulative handle 46 surrounds the electrically hot connector 30.
In accordance with one embodiment of the present invention, a TIG welding torch is provided having a torch head section similar to that shown in FIG. 1, but a different torch handle section. More specifically, the torch handle section has a male connector that connects the TIG torch section to a complementary (i.e., mating) female connector (i.e., receptacle) on the end of the power cable. In this embodiment, the male connectors and the female receptacle may be of the twist-lock or similar variety. In addition, a SMAW
electrode holder is provided that is interchangeable with the TIG welding torch.
In other words, the same power cable can be used with different heads, one having a TIG welding torch and the other having a SMAW electrode holder.
The power cable in accordance with the aforementioned embodiment will be described hereinafter with reference to FIGS. 2, 3, 6 and 7, while the TIG welding torch in accordance with the aforementioned embodiment will be described with reference to FIGS. 2-5. The SMAW
electrode holder in accordance with the aforementioned embodiment (which can be coupled to the power cable in place of the TIG welding torch in the assembly depicted in FIG. 3) will be described hereinafter with reference to FIGS.8-10.
Referring to FIG. 2, the components of the TIG torch headlpower cable assembly comprise a TIG welding torch 100 (only partially depicted), a TIG welding torch handle 102, a power cable 104 (only the ends of which are shown), and a power cable handle 106. The same components are shown in an assembled state in FIG. 3.
The TIG welding torch comprises an electrically conductive skeleton 108 (shown in FIG. 4), which is partially overmolded with electrically insulative material, as shown in FIG. 5. Referring to FIG. 4, the electrically conductive skeleton 108 comprises a coupling 50 and a male connector 52 (which may be formed as one piece, as seen in FIG. 4, or as two pieces connected together). The skeleton further comprises a tube 28 having one end brazed to the coupling 50 and the other end connected to a barrel 2 (also part of the skeleton). The skeleton components may be made of copper, brass or other suitable electrically conductive material suitable for carrying welding current. The coupling 52 has a central circular cylindrical bore 53 for passage of shielding gas. The bore 53 is coaxial with the bore of tube 28. The barrel 2 and the tube 28 are overmolded with electrically insulative material, thereby forming cylindrical body 40 (with shoulder 42 and ribs 44) surrounding the tube and a jacket 18 surrounding the barrel, as seen in FIG. 5.
The TIG welding torch is shown in FIGS. 2 and 3 without the nozzle, back cap, collet, collet body, and tungsten electrode, which may be similar to those components as depicted in FIG. 1. FIGS. 2 and 3 each show the front collar 16 and the back collar 20, both of which are made of electrically insulative material.

As seen in FIG. 2, the power cable has a female receptacle 54 at the head end and a male plug, comprising a nut 58 and a nipple 58', at the end that connects to the welding power supply unit. The latter end will typically be male, but could be female, and could be threaded, international style, a lug, or permanently affixed to the welding power supply. The cable comprises a hose 56 made of flexible, electrically insulative material and having a circular channel for the passage of shielding gas. One end of the hose 56 is crimped onto a nipple 64 (shown in dashed fines in FIG. 2) by a brass ferrule 60. The nipple and the female receptacle 54 are formed as one piece, as best seen in FIG. 6.
The other end of the hose 56 is crimped onto a nipple 58' by a ferrule 61. One end of a cable 62 is crimped onto nipple 58'. The cable 62 carries welding current from the power supply to the female receptacle 54 and has a cylindrical gas passage through the center.
The components depicted in FIG. 2 are assembled as follows.
First, the power cable handle 106 is slid over the head end of the power cable 104. As seen in FIG. 7, the power cable handle 106 has a bore 94 with an internally threaded section 96. The threaded section 96 engages the externally threaded female receptacle 54, enabling the handle 106 to be tightened onto the head end of the power cable 104. Next, the torch handle 102 is slid over the power cable 106. Then the male connector 52 of the TIG welding torch 100 (see FIG. 5) is inserted into an opening 78 formed in the female receptacle 54 (see FIG. 6). The opening in the female receptacle has a shape that matches the end profile of the male connector, which is a circular tube shape with a projection or key 51 (see FIG. 5) on its outer peripheral surface. The male connector 52 can only be inserted into the female receptacle when projection 51 is aligned with a corresponding recess that forms part of the opening in the female receptacle. The male connector 52 is inserted until projection 51 is aligned with the entrance to a groove 76 (see FIG. 6) defined in part by a shoulder having a ramped wall or cam 77 in the shape of a helical section that transitions to a landing at a stopping point. By turning the torch relative to the power cable, the projection 52 enters the groove, rides along the helical surface 77 (thereby tightening the male connector inside the female receptacle), and is stopped at a fully tightened position. The entire rotation of the torch relative to the power cable during coupling may be on the order of one-half tum.
After the male connector of the welding torch 100 is tightly coupled to the female receptacle at the head end of the power cable 104, the torch handle 102 is slid toward the torch. More specifically, the torch handle is slid over the ribbed portion of the molded cylindrical body 40. The ribbed portion comprises a circular cylindrical section having a plurality of external annular ribs 44 projecting radially outward at regular spaced intervals along a longitudinal axis. Each rib 44 has an outer diameter greater than the internal diameter of section 98 of the internal bore of the torch handle 102 (see FIG.
2).
However, since the molded body 40 and its ribs 44 are made of resilient material, the ribs 44 will compress as the torch handle 102 is pushed onto the ribbed cylindrical section. When the end of the torch handle 102 abuts the shoulder 42, as seen in FIG. 3, the torch handle cannot be pushed further. In the state shown in FIG. 3, the friction between the compressed ribs 44 and the internal surface 98 (see FIG. 2) holds the torch handle 102 securely in place.
As shown in FIG. 6, the female receptacle 54 is integrally formed with a nipple 64, which is inserted inside the hose of the power cable. A
section of the nipple 64 is provided with a series of conical ridges 70 that slide easily into the hose. and resist being pulled out of the hose. As previously described, the hose has a circular channel for the passage of shielding gas from the shielding gas supply through the power cable and toward the welding torch.
Although not shown in the drawings, the end of the nipple 64 is D-shaped after being crimped onto the weld cable. In other words, the nipple 64 has a flat side 66 that provides relief for the shielding gas to flow into a gas port 68. The piece shown in FIG. 6 also has a circular central channel 72 for the shielding gas.
One end of the channel 72 communicates with the space adjacent the flat side 66 via the gas port 68. The other end of the channel 72 (located inside the female receptacle 54) will communicate with one side of an O-ring 79 (see FIG.

6), which is seated along the periphery of a disk-shaped space 74 in the female receptacle 54. The space 74 communicates with one end of channel 72. The male connecter 52 is inserted into female receptacle 54 and rotated. When the male connector and female receptacle are tightly coupled, the O-ring 79 is compressed between the end of the male connector and the female receptacle 54 to form a hermetic seal that prevents shielding gas from leaking through the interstice between the male and female connectors. Instead, the shielding will flow under pressure from the channel 72 (see FIG. 6) into the bore 53 of the coupling 50, and then down the bore of the tube 28 (see FIG. 4).
When the operator wishes to interchange a SMAW electrode holder for the TIG welding torch 100 shown in FIGS. 2 and 3, the torch handle 102 is slid away from the torch and the torch is unscrewed from the power cable. Both the torch 100 and torch handle 102 are then removed and replaced by a SMAW electrode holder (shown in FIG. 8) and a Stick handle (shown in FIGS. 9 and 10).
Referring to F1G. 8, the SMAW electrode holder 110 comprises a body 80 made of electrically conductive material (e.g., brass). One end of the body 80 forms a jaw 84. Another jaw 82 (made, e.g., of the same electrically conductive material) is connected to a lever 86, the jaw 82 and lever 8fi being operatively coupled to the body 80 by a hinge point (not shown in FIG. 8) and a coil spring 88. When the lever 86 is depressed, the jaws 82 and 84 open and a consumable electrode (not shown) can be inserted between the jaws. When the lever is released, the coil spring 88 causes the jaws to hold the consumable electrode securely. The jaws are covered by respective covers 90 and 92 made of an electrically insulative material, such as thermoset plastic.
A male connector 52' is connected to the other end of the body 80. The end of the male connector 52' is similar in external shape to the end of the male connector in the TIG welding torch, but differs in that it lacks a passageway or channel for shielding gas, i.e., the male connector 52' can be solid, not hollow. The male connector 52' is inserted into the above-described female receptacle and locked in place when the projection or key 51 is rotated into the groove inside the female receptacle and latched behind a shoulder that forms that groove. In the particular example disclosed herein, the female receptacle 54 (see FIG. 6) is an International-style receptacle.
The electrode holder handle 112 (see FIG. 9) is a generally circular cylindrical structure that slides over the body 80 (see FIG. 8) of the SMAW electrode holder. The bore 114 of the handle 112 intersects the annular plateau 81 formed on the body 80. The handle 112 has a slot 118 (see FIG. 10) that provides clearance for the lever 86 and the coil spring 88. The handle is then secured by a set screw 83 whose head is backed into a circular hole 85 in the handle. The insertion of the screw head into hole 85 prevents the handle from sliding off.
The power cable (104 in FIG. 3) can carry current for either TIG
welding or SMAW. The female receptacle has a passageway for shielding gas.
When a TIG welding torch is connected to the female receptacle, the power cable provides both welding current and shielding gas to the TIG welding torch.
When a SMAW electrode holder is connected to the female receptacle, the power cable provides only welding current, i.e., the passageways for shielding gas are not used.
While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for members thereof without departing from the scope of the invention. In addition, many mod~cations may be made to adapt a particular situation to the teachings of the invention without departing from the essential scope thereof.
Therefore it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims (21)

1. A kit comprising:
a power cable comprising a female receptacle at a head end;
a TIG welding torch comprising a first plug that can be coupled in said female receptacle of said power cable; and a SMAW electrode holder comprising a second plug that can be coupled in said female receptacle of said power cable.

2. The kit as recited in claim 1, wherein the portion of said first plug that couples to said female receptacle has a structure substantially the same as the structure of the portion of said second plug that couples to said female receptacle.

3. The kit as recited in claim 1, wherein said TIG torch comprises a tungsten electrode electrically coupled to said first plug.

4. The kit as recited in claim 1, wherein said SMAW electrode holder comprises a pair of jaws electrically coupled to said second plug.

5. The kit as recited in claim 1, wherein the coupling between said female receptacle and said first or second plug is of the twist-lock variety.

6. The kit as recited in claim 1, wherein said power cable comprises a channel for shielding gas.

7. The kit as recited in claim 6, wherein said power cable comprises an electrical conductor disposed inside said channel.

8. A kit comprising:
a power cable comprising a female receptacle at a head end;
a TIG welding torch comprising a first male connector that can be coupled in said female receptacle of said power cable; and a SMAW electrode holder comprising a second male connector that can be coupled in said female receptacle of said power cable, wherein said female receptacle is not threadably engaged with the portion of said first or second male connector inserted therein.

9. The kit as recited in claim 8, wherein the portion of said first male connector that couples to said female receptacle has a structure substantially the same as the structure of the portion of said second male connector that couples to said female receptacle.

10. The kit as recited in claim 8, wherein said TIG torch comprises a tungsten electrode electrically coupled to said first male connector.

11. The kit as recited in claim 8, wherein said SMAW electrode holder comprises a pair of jaws electrically coupled to said second male connector.

12. The kit as recited in claim 8, wherein the coupling between said female receptacle and said first or second mate connector is of the twist-lock variety.

13. The kit as recited in claim 8, wherein said power cable comprises a channel for shielding gas.

14. The kit as recited in claim 13, wherein said power cable comprises an electrical conductor disposed inside said channel.

15 15. An assembly comprising:
a power cable comprising an electrical conductor running the length of said power cable, a first electrical connector at a head end of said power cable and a second electrical connector at the other end of said power cable, and further comprising a channel running along the length of said power cable, said channel being at least partially occupied by a gas; and a SMAW electrode holder comprising a third electrical connector coupled to said first electrical connector of said power cable.

16. The assembly as recited in claim 15, wherein said first electrical connector comprises a channel in fluid communication with said channel of said power cable.

17. The assembly as recited in claim 15, wherein said first electrical connector comprises a female receptacle.

18. The assembly as recited in claim 17, wherein said female receptacle is not threadably engaged with a portion of said third electrical connector inserted therein.

19. The assembly as recited in claim 15, wherein said electrical conductor is disposed in said channel.

20. A method for changing the welding mode of a welding system: comprising the following steps:
uncoupling a first welding head from a head end of a power cable by a relative movement different than unscrewing; and coupling a second welding head from said head end of said power cable by a relative movement different than screwing, wherein one of said first and second welding heads is a TIG
welding torch and the other of said first and second welding heads is a SMAW

electrode holder.

21. The method as recited in claim 20, wherein said coupling step comprises the steps of inserting, twisting and locking a male connector of said second welding head inside a female receptacle of said head end of said power cable.