Abstract:
A welding torch includes an electrical commutation device configured to receive welding power. The electrical commutation device is also configured to transfer the welding power between a welding power input and welding wire before the welding wire passes through a guide device that directs the welding wire out of the welding torch.

Description:
BACKGROUND 
       [0001]    The invention relates generally to welding torches, and, more particularly, to systems and devices for power commutation in a welding torch. 
         [0002]    Welding is a process that has become increasingly ubiquitous in various industries and applications. Such processes may be automated in certain contexts, although a large number of applications continue to exist for manual welding operations. In both cases, such welding operations rely on a variety of types of equipment to ensure that the supply of welding consumables (e.g., wire, shielding gas, etc.) is provided to the weld in an appropriate amount at the desired time. For example, metal inert gas (MIG) welding typically relies on a wire feeder to enable a welding wire to reach a welding torch. The wire is continuously fed during welding to provide filler metal. A power source ensures that arc heating is available to melt the filler metal and the underlying base metal. 
         [0003]    In MIG welding applications, the wire feeder typically provides a continuous feed of welding wire so long as a trigger is actuated by the welding operator. The welding wire is fed through a contact tip that is surrounded by a nozzle. Generally, the contact tip provides an electrical path to allow welding power to flow between a welding power supply and the welding wire. During a welding application, spatter from melted welding wire may form on the contact tip of the welding torch. If there is sufficient spatter buildup, welding wire may jam within the contact tip. Likewise, erosion of or metal buildup in the bore of the contact tip caused by electrical arcing between the contact tip and the welding wire may cause loss of electrical contact or obstruction of the wire resulting in a burn back. When welding wire is jammed or burned back onto the end of the contact tip, actuating the trigger may cause bird nesting of the welding wire within the welding torch. Further, in certain configurations, the size of the nozzle surrounding the contact tip may inhibit the welding torch from reaching a desired welding location. As will be appreciated, the contact tip may become very hot during a welding application causing shielding gas to be superheated. As shielding gas is superheated, it becomes less dense which decreases the quality of the shielding during the welding application. Accordingly, there is a need in the field for techniques that might provide alternative torch configurations to overcome such deficiencies. 
       BRIEF DESCRIPTION 
       [0004]    In one embodiment, a welding torch includes a neck having conductive elements configured to receive welding power. The neck is configured to enable shielding gas and welding wire to pass therein. The welding torch also includes a conductive assembly electrically coupled to the conductive elements and configured to enable welding power to flow between the conductive elements and the welding wire. The welding torch includes a guide tip coupled to the neck and electrically insulated from the conductive assembly to inhibit welding power from passing through the guide tip. The guide tip is configured to direct welding wire to flow from the neck to a welding application. 
         [0005]    In another embodiment, a welding device includes a guide tip including material that inhibits welding power from flowing through the guide tip. The guide tip may be substantially electrically non-conductive, thermally non-conductive, or some combination thereof. 
         [0006]    In another embodiment, a welding torch includes a neck having a conductive portion and a passageway. The conductive portion is configured to enable welding power to flow to the welding operation, and the passageway is configured to enable welding wire to flow to the welding application. The welding torch also includes a wire guide device coupled to the neck and configured to allow welding wire to flow from the neck to the welding application. The wire guide device is configured to inhibit welding power from flowing through the wire guide device. 
         [0007]    In another embodiment, a welding torch includes an electrical commutation device configured to receive welding power. The electrical commutation device is also configured to transfer the welding power between a welding power input and welding wire before the welding wire passes through a guide device that directs the welding wire out of the welding torch. 
         [0008]    In another embodiment, a welding torch includes an electrical commutation device electrically coupled to a neck to receive welding power and configured to transfer welding power between the neck and welding wire. The welding torch also includes a guide device coupled to the neck and configured to be electrically isolated from the welding power. The guide device includes an electrically conductive material, a thermally conductive material, or some combination thereof. 
     
    
     
       DRAWINGS 
         [0009]    These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
           [0010]      FIG. 1  is a perspective view of an embodiment of a welding power supply employing a welding torch with power commutation according to the present disclosure; 
           [0011]      FIG. 2  is a break-away view of an embodiment of a portion of the welding torch of  FIG. 1 ; 
           [0012]      FIG. 3  is a cross-sectional view of an embodiment of a portion of the welding torch of  FIG. 1 ; 
           [0013]      FIG. 4  is a partial cross-sectional view of an embodiment of a conductive assembly of the welding torch of  FIG. 3 ; and 
           [0014]      FIG. 5  is a partial cross-sectional view of another embodiment of a conductive assembly of the welding torch of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Turning now to the drawings,  FIG. 1  is a perspective view of an exemplary welding power supply  10  configured for use in a gas metal arc welding (GMAW) process. The welding power supply  10  includes a housing  12  having a top panel  14 , a side panel  16 , and a front panel  18 . The top panel  14  may include a handle that facilitates transport of the welding power supply  10  from one location to another by an operator if desired. The front panel  18  includes a control panel  20  adapted to allow an operator to set one or more parameters of the welding process, for example, via knobs  22  (or buttons, touchscreens, etc.). 
         [0016]    In certain embodiments, the welding power supply  10  includes the functionality of a wire feeder (i.e., internal wire feeder). Such embodiments may include a wire drive configured to receive control signals to drive a wire spool. The wire drive feeds wire for the welding operation. In other embodiments, a separate wire feeder may attach to the welding power supply  10  (i.e., external wire feeder). Such a separate wire feeder may also include a wire drive and a wire spool. 
         [0017]    A main electrical connector  24  couples to the welding power supply  10  via the front panel  18 . A cable  26  extends from the main connector  24  to a welding torch  28  configured to be utilized in a welding operation to establish a welding arc. As will be appreciated, the welding torch  28  may include a conductive assembly that directs welding power through the welding wire so that welding power does not have to flow through a guide or contact tip of the torch  28 . Further, in certain embodiments, the guide or contact tip may be manufactured from a material that inhibits welding power from flowing through the tip. For example, the contact or guide tip may be manufactured using a ceramic material, or another suitable material. As such, welding power may be transferred to welding wire using the conductive assembly rather than the guide or contact tip, resulting in reduced arc related deterioration of the guide or contact tip and reduced occurrence of burnbacks (e.g., where the welding wire fuses to the end of the guide or contact tip). 
         [0018]    The welding torch  28  includes a trigger  30  that initiates a welding operation and causes welding wire to be supplied to the welding operation by exposing welding wire when pressed. Furthermore, pressing the trigger  30  may cause a switch in the trigger  30  to be actuated. In certain embodiments, wire may be supplied to a welding operation using a spoolgun attached to a welding power supply. In such configurations, the spoolgun may include a trigger to supply welding wire. 
         [0019]    A second cable  32  is attached to the welding power supply  10  through an aperture in the front panel  18  and terminates in a clamp  34  that is adapted to clamp to the workpiece during a welding operation to close the circuit between the welding power supply  10 , the welding torch  28 , and the workpiece. During such an operation, the welding power supply  10  is configured to receive primary power from a primary power supply, such as a power source (e.g., the power grid, engine-generator, etc.), to condition such incoming power, and to output a weld power output appropriate for use in the welding operation. Further, the welding power supply  10  may be configured to receive shielding gas, such as from a gas supply cylinder. 
         [0020]      FIG. 2  is a break-away view of a portion of the welding torch  28  of  FIG. 1 . The welding torch  28  includes a handle  36  for a welding operator to hold while performing a weld. At one end  38 , the handle  36  is coupled to the cable  26  where welding consumables are supplied to the weld. Welding consumables generally travel through the handle  36  and exit at an end  40 , which is disposed on the handle  36  at an end opposite from end  38 . The welding torch  28  includes a neck  42  extending out of the end  40 . As such, the neck  42  is coupled between the handle  36  and a nozzle  44 . As should be noted, when the trigger  30  is pressed or actuated, welding wire travels through the cable  26 , the handle  36 , the neck  42 , and the nozzle  44 , so that the welding wire extends out of an end  46  (i.e., torch tip) of the nozzle  44 . 
         [0021]    As illustrated, the handle  36  is secured to the neck  42  via fasteners  48  and  50 , and to the cable  26  via fasteners  52  and  54 . The nozzle  44  is illustrated with a portion of the nozzle  44  removed to show welding wire  56  extending out of a guide or contact tip  58  (or other guiding device). The guide tip  58  is used to guide the welding wire  56  out the end  46  of the welding torch  28 . Welding power is commuted to the welding wire  56  using a conductive assembly within the neck  42  or another part of the welding torch  28 . As such, power does not need to flow through the guide tip  58 . Consequently, in certain embodiments, the guide tip  58  is constructed to inhibit welding power from flowing through the guide tip  58  (e.g., the guide tip  58  is generally electrically non-conductive) and/or the guide tip  58  is constructed to inhibit thermal energy from a welding application from being conducted through the guide tip  58  (e.g., the guide tip  58  is generally thermally non-conductive). For example, the guide tip  58  may be constructed using a ceramic based material, or another suitable (e.g., substantially electrically non-conductive and/or substantially thermally non-conductive) material. In certain embodiments, the material for constructing the guide tip  58  may include one or more of nitrides, borides, carbides, and oxides. For example, the guide tip  58  may be constructed using aluminum oxide, or zirconium oxide. Due to the composition of the guide tip  58 , the guide tip  58  does not absorb as much heat as other contact tips, such as those constructed using copper. Because of lower temperatures in the guide tip  58 , spatter buildup on the guide tip  58  is reduced and shielding gas superheating is inhibited, which results in more efficient welding operations. In other embodiments, the guide tip  58  comprises a generally conductive material (e.g., copper). In such embodiments, welding power is transferred between an electrical commutating device in the welding torch  28  and the welding wire  56  within the torch  28  prior to the welding wire  56  entering an opening within the guide tip  58 . Further, the guide tip  58  is electrically insulated from the welding power circuit. Therefore, welding power does not flow through the material of the guide tip  58 , resulting in less electrical arc related deterioration of the guide tip  58  and it eliminates the potential for burnbacks (where the welding wire fuses to the end of the guide tip  58 ). 
         [0022]      FIG. 3  is a cross-sectional view of an embodiment of a portion of the welding torch  28  of  FIG. 1  using the guide tip  58 . As illustrated, the guide tip  58  includes a central opening  60  (e.g., wire guide feature) to allow welding wire  56  to flow through the guide tip  58 . Further, the guide tip  58  includes openings  62  that allow shielding gas to flow through the guide tip  58 . Although four such openings  62  are depicted, the guide tip  58  may have any number of openings  62  that allow shielding gas to flow through the guide tip  58  (e.g., fewer or more than four openings). In the present embodiment, the guide tip  58  is coupled directly to the neck  42  of the welding torch  28 . Specifically, a threaded end  64  of the neck  42  is inserted into the guide tip  58  and threadingly engaged with a threaded end  66  of the guide tip  58 . The threads of the guide tip  58  are shown on the internal circumference of the threaded end  66  while the threads of the neck  42  are shown on the external circumference of the threaded end  64 . However, in certain embodiments, the threads of the guide tip  58  may be on the external circumference of the threaded end  66  while the threads of the neck  42  may be on the internal circumference of the threaded end  64 . In such an embodiment, the guide tip  58  is inserted into the neck  42  to threadingly engage the threaded ends  64  and  66 . In other embodiments, the guide tip  58  may be connected to the neck  42  of the welding torch  28  by a set screw or any number of other clamping or holding methods or devices. 
         [0023]    The welding torch  28  of the present embodiment does not include the nozzle  44  surrounding the guide tip  58 . As such, the guide tip  58  may be used to perform welds in locations that are not accessible to embodiments using the nozzle  44 . As will be appreciated, in embodiments where the nozzle  44  is used, the guide tip  58  may not have the openings  62  because shielding gas may flow around the outside of the guide tip  58  and within the nozzle  44 . The guide tip  58  having opening  60  and/or openings  62  may be manufactured using any suitable manufacturing technique. For example, the guide tip  58  may be formed using a mold. 
         [0024]    The neck  42  of the welding torch  28  may be constructed with an external layer  68  and an internal layer  70 , both formed around an internal passageway  72 . In certain embodiments the external layer  68  may be manufactured using an insulative material. The internal layer  70  is manufactured using a conductive material or conductive elements to allow welding power to flow therethrough. In certain embodiments, conductive elements are used instead of the internal layer  70 . The internal passageway  72  provides a pathway for shielding gas to flow through the neck  42  to the guide tip  58 . 
         [0025]    A conductive assembly  74  (e.g., electrical commutating device) is electrically coupled to the internal layer  70  within the internal passageway  72 . The conductive assembly  74  allows welding power to flow between the internal layer  70  and the welding wire  56 . As such, the conductive assembly  74  may be formed in any suitable manner. For example, the conductive assembly  74  may be formed as illustrated in the present embodiment, as illustrated in  FIG. 4 , or as illustrated in  FIG. 5 . Further, the conductive assembly  74  may be formed using carbon brushes, carbon fiber brushes, wire brushes, wire fiber brushes, ionized gas plasma, and so forth. As discussed above, the conductive assembly  74  allows welding power to be transferred between the conductive assembly  74  in the welding torch  28  and the welding wire  56  within the torch  28  prior to the welding wire  56  entering the central opening  60  within the guide tip  58 . 
         [0026]    In the present embodiment, the conductive assembly  74  includes conductive springs  75  and conductive shoes  76  (e.g., carbon shoes). The conductive springs  75  press the conductive shoes  76  against the welding wire  56  with sufficient force to enable conduction between the conductive shoes  76  and the welding wire  56 . However, the force between the conductive shoes  76  and the welding wire  56  does not inhibit the flow of welding wire  56  to a welding operation. Thus, welding power is transferred between the internal layer  70  and the welding wire  56  using the conductive assembly  74 , thereby enabling the use of a non-conductive guide tip  58 . As will be appreciated, by commutating power to the welding wire  56  using the conductive assembly  74 , the purpose of the guide tip  58  may be limited to guiding welding wire  56  out the end of the welding torch  28 . Therefore, in certain embodiments, the guide tip  58  may be replaced with any suitable device for guiding welding wire  56  out the end of the welding torch  28 . For example, in certain embodiments, the guide tip  58  may be replaced with rollers, tubing, or any other type of guiding mechanism. 
         [0027]      FIG. 4  is a partial cross-sectional view of an embodiment of the conductive assembly  74  of the welding torch  28  of  FIG. 3 . In this embodiment, a conductive cylinder  84  (e.g., carbon cylinder) with a jogged opening  75  is used to allow welding power to flow between the internal layer  70  and the welding wire  56 . Specifically,  60847  the conductive cylinder  84  is inserted within the internal passageway  72  and maintains contact with the internal layer  70 . The jogged opening  75  forces the welding wire  56  to include bends  86  which contact the conductive cylinder  84  at multiple locations and maintain conduction between the conductive cylinder  84  and the welding wire  56 . Thus, welding power is transferred between the internal layer  70  and the welding wire  56  using the conductive assembly  74 , thereby enabling the use of a non-conductive guide tip  58 . 
         [0028]      FIG. 5  is a partial cross-sectional view of another embodiment of the conductive assembly  74  of the welding torch  28  of  FIG. 3 . In this embodiment, conductive rollers  88 ,  90 , and  92  are used to allow welding power to flow between the internal layer  70  and the welding wire  56 . Specifically, the conductive rollers  88 ,  90 , and  92  are inserted within the internal passageway  72  and maintain contact with the internal layer  70 . The gaps between the conductive rollers  88 ,  90 , and  92  force the welding wire  56  to include bends  94  which contact the conductive rollers  88 ,  90 , and  92  and maintain conduction between the conductive rollers  88 ,  90 , and  92  and the welding wire  56 . Thus, welding power is transferred between the internal layer  70  and the welding wire  56  using the conductive rollers  88 ,  90 , and  92 , thereby enabling the use of a non-conductive guide tip  58 . As will be appreciated, in certain embodiments, one or more of the rollers  88 ,  90 , and  92  may be non-conductive; however, at least one of the rollers  88 ,  90 , and  92  is conductive. 
         [0029]    While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.