Abstract:
A drive roll for advancing a wire is provided. In certain embodiments, the drive roll includes a body having a wire feed portion, a mounting portion, and a central aperture through the body. In one embodiment, the feed portion includes an outer circumferential surface of the drive roll and a plurality of grooves for receiving and advancing various wires, while the mounting portion includes mounting features that are each uniquely associated with only one of the grooves. Various wire feed systems and welding systems are also provided.

Description:
BACKGROUND 
       [0001]    The invention relates generally to welding systems and, more particularly, to wire feed assemblies of such systems. 
         [0002]    A common metal welding technique employs the heat generated by electrical arcing to transition a portion of a workpiece to a molten state, and the addition of filler metal from a wire or electrode. One technique that employs this arcing principle is wire-feed welding. At its essence, wire-feed welding involves routing welding current from a power source into an electrode that is brought into close proximity or contact with the workpiece. When the electrode is sufficiently close to or touching the workpiece, current arcs from the electrode to the workpiece, completing a circuit and generating sufficient heat to melt and weld the workpiece. Often, the electrode is consumed and becomes part of the weld itself. Thus, new wire electrode is advanced, continuously replacing the consumed electrode and maintaining the welding arc. If the welding device is properly adjusted, the wire-feed advancement and arcing cycle progresses smoothly, providing a good weld. One common type of wire-feed welding is metal inert gas or “MIG” welding. 
         [0003]    In typical wire-feed systems, wire electrode is advanced by a wire feeder and directed through a welding cable, into a torch assembly, and into a contact tip housed within the torch assembly. Electrical current is routed from the welding cable to the wire electrode through the contact tip. When a trigger on the welding torch is operated, wire electrode is advanced toward the contact tip, at which point current is conducted from the contact tip into the advancing electrode. 
         [0004]    As will be appreciated, it may be desirable to change the type of wire electrode used by a welding system based on the particular workpiece. For instance, welding operations performed on two different workpieces may benefit from using wire electrodes of different sizes or compositions. However, wire feeders within such systems typically include drive rolls disposed at fixed positions with respect to a path in which a wire electrode is advanced. These typical drive rolls may have a single groove configured to receive a particular type of wire or a pair of grooves on opposite ends of the drive roll for receiving two types of wire. In the case of the former, an operator is generally required to remove the drive roll from the system and replace it with a different drive roll in order to configure the system for use with a different wire type. In the latter instance, the two-groove drive roll must be removed from the system, reversed, and reinstalled to align the desired groove with the wire path. Consequently, these common drive rolls are generally configured to advance only one or two types of wire electrodes, and typically require disassembly of a portion of the welding system in order to change between various wire types. 
         [0005]    Therefore, there exists a need for an improved drive assembly for welding devices that facilitates quicker and easier configuration of the welding system for use with different wire electrodes. 
       BRIEF DESCRIPTION 
       [0006]    As discussed in detail below, certain embodiments of the present invention may provide an improved drive roll for a wire feed system. In one embodiment, the drive roll includes a plurality of circumferential grooves that are collectively configured to receive and advance wires of various sizes and/or compositions. Each groove is associated with a respective mounting recess or recesses, and the drive roll is configured such that a particular groove is aligned with a wire path of the wire feed system when an alignment member, such as a tab on a shaft to which the drive roll is mounted, is disposed within the mounting recess corresponding to the particular groove. Various other configurations, in addition to systems including one or more such drive rolls, are also envisaged. 
     
     
       DRAWINGS 
         [0007]    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: 
           [0008]      FIG. 1  is a diagrammatic representation of a welding system, in accordance with one embodiment of the present invention; 
           [0009]      FIG. 2  is an exploded view of the exemplary drive system of  FIG. 1 , in accordance with one embodiment of the present invention; 
           [0010]      FIG. 3  is front perspective view of a drive roll of the drive system of  FIG. 2 , the exemplary drive roll having a plurality of circumferential grooves in accordance with one embodiment of the present invention; 
           [0011]      FIG. 4  is a rear perspective view of the drive roll of  FIG. 3 ; 
           [0012]      FIG. 5  is a sectional view of the drive roll illustrated in  FIGS. 3 and 4 ; 
           [0013]      FIG. 6  is a detailed view of the drive roll illustrated in  FIGS. 3-5  installed in an exemplary drive assembly and set to align one circumferential groove with a wire path in the drive assembly in accordance with one embodiment of the present invention; and 
           [0014]      FIG. 7  is a detailed view of the drive roll and assembly illustrated in  FIG. 6 , depicting adjustment of the drive roll between various settings to alternatively align circumferential grooves with the wire path in accordance with one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    One or more exemplary embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
         [0016]      FIG. 1  illustrates an exemplary wire-feed welding system  10  that includes an adjustable drive roll in accordance with certain embodiments of the present technique. Prior to continuing, however, it should be noted that the following discussion merely relates to exemplary embodiments of the present technique. As such, the appended claims should not be viewed as limited to those embodiments specifically described herein. 
         [0017]    The exemplary welding system  10  includes a plurality of components disposed within a housing  12 , including a drive system  14 . In operation, the drive system  14  advances a wire electrode  16  from the housing  12  to a welding torch or gun  18 . This wire electrode  16  may be fed from a wire spool  20  disposed within the housing  12 . Particularly, in the presently illustrated embodiment, a power supply  22  provides operating power to a motor  24  of the drive system  14  to facilitate advancement of the wire electrode  16 . As will be appreciated, the wire electrode  16  may be advanced through a supply cable  26  to a contact tip within the nozzle  28  of the welding torch  18 . 
         [0018]    During a welding operation, placement of the nozzle  28  at a location proximate to a workpiece  30  allows electrical current provided by the power supply  22 , which is routed to the welding torch  18  via the supply cable  26 , to arc from the welding torch  18  to the workpiece  30 . In short, this arcing completes an electrical circuit that includes the power supply  22 , the welding torch  18 , the workpiece  30 , a ground clamp  32 , and a ground cable  34 . Particularly, in one embodiment, current passes from the power supply  22 , to the welding torch  18  via the supply cable  26 , to a portion of the wire electrode  16  within the welding torch  18 , and then arcs to the workpiece  30 . This arcing generates a relatively large amount of heat that causes the workpiece  30  and/or a filler metal to transition to a molten state, thereby facilitating the weld. As will be appreciated, such filler metal may be provided by the wire electrode  16  or from some other source. 
         [0019]    It bears noting that a wide array of wire electrodes  16  may be used in the exemplary system  10  in full accordance with the present techniques. For instance, the wire electrode  16  may comprise any of a variety of suitable metals, such as aluminum, stainless steel, nickel, or iron, for instance. Additionally, in some embodiments, the wire electrode  16  may be a solid wire or a cored wire, including a flux cored or gasless wire electrode. As will be further appreciated, various welding electrodes  16  may also have different widths or diameters than one another, such as diameters of 0.024 inches, 0.030 inches, and 0.035 inches, to name but a few. Indeed, as discussed in greater detail below, the drive system  14  may be configured to advance a variety of wire electrodes  16  that may differ in size and/or composition. 
         [0020]    To shield the weld area from contaminants during welding, to enhance arc performance, and to improve the resulting weld, a shielding material  36  may be provided from a cylinder  38  to the welding torch  18  via the supply cable  26 . In one embodiment, the shielding material  36  is an inert gas. It should be noted, however, that a wide variety of shielding materials may be utilized in addition to, or in place of, an inert gas, including active gases, various other fluids, and particulate solids. It will also be appreciated that other embodiments, such as those employing gasless wire electrodes, may not greatly benefit from a shielding material  36  and, accordingly, may or may not include the cylinder  38 . The shielding material  36  may enter an outlet hose  40  through a regulator  42  of the cylinder  38  and ultimately pass to a neck portion  44  of the welding torch  18  via the supply cable  26 . 
         [0021]    An exemplary drive assembly  50  of the drive system  14  is illustrated in  FIG. 2 . The drive assembly  50  includes a mounting or support structure  52  that receives first and second drive roll assemblies  54  and  56 , respectively. In the presently illustrated embodiment, the drive roll assemblies  54  and  56  are generally disposed opposite one another, each assembly including a drive roll  60 . The drive roll assemblies  54  and  56  cooperate to advance the wire electrode  16  to the welding torch  18 , as discussed above. 
         [0022]    The exemplary first drive roll assembly  54  may be mounted on a shaft  62  of the motor  24 , which includes one or more locking members or tabs  64  configured to apply torque to the first drive roll assembly  54  during operation of the motor  24 . A biasing spring  66  may be provided to bias the first drive roll assembly  54  into engagement with the tabs  64  of the shaft  62 . To facilitate installation, the drive roll  60  of the first drive roll assembly  54  includes a slot  68  for receiving the shaft  62  and the tabs  64 . 
         [0023]    The drive roll  60  of the first drive roll assembly  54  includes a plurality of mounting or alignment recesses  72  for receiving the tabs  64  of the shaft  62 . Particularly, when installed on the shaft  62 , the biasing spring  66  applies a biasing force to the first drive roll assembly  54 , facilitating engagement of the tabs  64  within one or more of the recesses  72 . Once the tabs  64  are disposed in such recesses, rotation of the shaft  62  transmits a torque to the drive roll  60  of the first drive roll assembly  54  via the tabs  64 . This torque may then be transmitted to the second drive roll assembly  56 , such as through a frictional force, causing rotation of the second drive roll assembly  56  about a pivot or rotational axis  74 . 
         [0024]    In one embodiment, the second drive roll assembly  56  is secured to a tension arm  76  that may rotate about a pivot  78 , as generally indicated by arrow  80 , to allow the second drive roll assembly  56  to be positioned closer to or further from the first drive roll assembly  54 . Particularly, the drive system  14  may include a wire path  82  that generally defines the route of a wire electrode  16  through the drive system  14 . In particular, in the present embodiment, the wire path  82  passes from an inlet guide  86  to an outlet guide  88  between the first and second drive roll assemblies  54  and  56 . Various grooves  84  may be disposed on one or both of the drive rolls  60  to advance a wire electrode  16  between the inlet and outlet guides  86  and  88 . 
         [0025]    The drive assembly  50  may also include a coupling  90  that facilitates connection of the welding torch  18  to the drive system  14 , such as via the supply cable  26 . In one embodiment, the coupling  90  includes a shielding material inlet port  92  for receiving a shielding material, such as the shielding material  36 , and transmitting the shielding material to the welding torch  18 . An adjustment knob  94  may also be incorporated into the drive assembly  50  to facilitate adjustments to the amount of force applied to a wire electrode  16  by the second drive roll assembly  56  and the tension arm  76 . 
         [0026]    An exemplary drive roll  60  is illustrated in  FIGS. 3-5 . In one embodiment, the respective drive rolls  60  of the first and second drive roll assemblies  54  and  56  may be substantially identical. However, in other embodiments, the drive roll  60  of each assembly may be different than one another, such as differing in size, configuration, or composition. For instance, in one embodiment, one of the drive rolls  60  may include a plurality of grooves  84 , while the other drive roll does not include such grooves. Indeed, in one embodiment, one of the drive rolls  60  may be essentially composed of a bearing that may or may not have grooves  84  or mounting recesses  72 . The drive rolls  60  may be formed from various suitable materials and manufacturing techniques, such as cast aluminum or machined steel, for instance. 
         [0027]    In the presently illustrated embodiment, the exemplary drive roll  60  may include a wire routing portion  100  that generally composes a first end of the drive roll  60 , and a mounting portion  102  that generally composes a second end of the drive roll  60 . The exemplary wire routing portion  100  includes a generally circumferential surface  104  having a plurality of grooves formed therein. As discussed in greater detail below, each of the grooves  84  may be configured to receive and advance a wire electrode  16  that is different in size and/or composition than the wire electrodes the other grooves are configured to receive. 
         [0028]    The mounting portion  102  includes a plurality of mounting recesses  106 ,  108 , and  110 , which are formed in a surface  112  of the drive roll  60 . Once assembled, the tabs  64  of the motor shaft  62  may be disposed within the mounting recesses  106 ,  108 , or  110 , each tab  64  abutting a mounting shoulder  114 ,  116 , or  118 , respectively. In the presently illustrated embodiment, the mounting recesses  106 ,  108 , and  110  are each composed of a related pair of mounting recesses that are disposed about an inner circumference of the drive roll  60  opposite one another. Each recess of the related pair has a depth, measured from the surface  112  to its respective mounting shoulder  114 ,  116 , or  118 , that is substantially equivalent to the depth of the other recess of the pair. 
         [0029]    In other words, each of the mounting recesses  106  has a depth from the surface  112  to their respective mounting shoulders  114  of similar magnitude. Likewise, in the present embodiment, each of the mounting recesses  108  has a common depth from the surface  112  to a respective mounting shoulder  116 , and each of the mounting recesses  110  has a common depth from the surface  112  to a respective mounting shoulder  118 . It should be noted, however, that other embodiments and configurations are also envisaged, such as one or more embodiments in which the drive roll  60  includes only single mounting recesses  106 ,  108 , and  110 , or sets of mounting recesses each having a number of related mounting recesses greater than two. 
         [0030]    In certain embodiments, each set of mounting recesses  106 ,  108 , and  110 , corresponds to a respective groove configured to receive a wire electrode of a specific size or diameter. For instance, in one embodiment, three grooves  84  associated with the mounting recesses may be disposed about the drive roll  60  and configured to receive wire electrodes having diameters of or near 0.024 inches, 0.030 inches, and 0.035 inches, respectively. Accordingly, indicators  120 ,  124 , and  126  may be disposed adjacent their respective mounting recesses to facilitate alignment of a particular groove  84  with the wire path  82  ( FIG. 2 ). Additionally, in one embodiment, the exemplary drive roll  60  includes a recessed portion  128  to facilitate engagement with other possible components of the drive roll assemblies  54  or  56  ( FIG. 2 ). 
         [0031]    In one embodiment, the grooves  84  include individual grooves,  134 ,  136 , and  138 . In the present embodiment, grooves  134 ,  136 , and  138 , are generally V-shaped. In other embodiments, however, one or more of the grooves  134 ,  136 , and  138  may have a different profile, such as generally U-shaped, to better accommodate advancement of a wire electrode having different strength or ductility. Further, while the presently illustrated embodiment provides three grooves  84 , other embodiments having a greater or fewer number of grooves are also envisaged. 
         [0032]    In this exemplary embodiment, the axial distance (generally taken along the axis  140 ) between the groove  134  and the mounting shoulder  114  is substantially identical to the axial distance between the groove  136  and the mounting shoulder  116  as well as that between the groove  138  and the mounting shoulder  118 . As will be appreciated, the spring  66  ( FIG. 2 ) applies a biasing force that causes one of the mounting shoulders  114 ,  116 , or  118  to engage a mounting tab  64  disposed within the respective mounting recess. The equidistant arrangement of the grooves  134 ,  136 , and  138 , with respect to their corresponding mounting shoulders  114 ,  116  and  118 , enables alignment of a particular groove with the wire path  82  ( FIG. 2 ) by disposing a tab  64  of the motor shaft  62  within a particular mounting recess  106 ,  108 , or  110 . Particularly, when the tabs  64  are disposed within the mounting recesses  106 , the biasing force applied by the spring  66  causes the tabs  64  to abut mounting shoulders  114 , which brings the groove  134  into alignment with the wire path  82  ( FIG. 2 ), as generally illustrated in  FIG. 6 . 
         [0033]    As noted by the indicator  120 , the groove  134  of the presently illustrated embodiment may be configured to receive and advance a wire electrode having a diameter of approximately 0.024 inches. However, to accommodate a wire electrode of a different size or composition, the drive roll  60  may be depressed, as generally indicated by the arrow  144  in  FIG. 7 , and rotated either clockwise or counterclockwise, as generally indicated by the arrow  146 , to align one of the other grooves, such as the groove  136  or the groove  138 , with the wire path  82 . When the tabs  64  are aligned with the desired mounting recesses, the drive roll  60  may be released such that the spring  66  biases the respective mounting shoulders toward the tabs  64 . 
         [0034]    As may be appreciated, when the tabs  64  are disposed within the mounting recesses  108  and in contact with the mounting shoulders  116 , the drive roll  60  is at a different axial position with respect to the shaft  62  than is the case if the tabs  64  were disposed in the mounting recesses  106 . This axial displacement, in consort with the equidistant nature of respective sets of grooves and mounting recesses, results in alignment of groove  136  with the wire path  82  when the tabs  64  are disposed within the mounting recesses  108 . Similarly, disposal of the tabs  64  within the mounting recesses  110  result in the alignment of groove  138  with the wire path  82 . Consequently, in this embodiment, the drive roll may be adjusted to advance a variety of wire electrodes  16  along the wire path  82  without the need for removing the drive roll  60  from the shaft  62 , thus facilitating quicker and easier adjustment of the drive roll and interchanging of different wire electrodes  16  for use in the welding system  10 . 
         [0035]    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.