Abstract:
An arc welding tool which includes a circular frame defining a passage for receiving a work piece, a carriage moveably positioned on the frame, and an electrical connector supported by the carriage, with an electrical path defined between the frame, carriage and electrical connector.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present disclosure relates generally to welding. In another aspect, the present invention relates to methods, apparatus and products for welding. In even another aspect, the present invention relates to methods, apparatus and products for welding rotating work pieces. 
         [0003]    2. Background of the Invention 
         [0004]    Arc welding consists of fusing or joining at least two pieces of metal by establishing a metallurgical bond between them. The process of arc welding comprises the use of an electric welding power supply to create an electric arc between an electrode and a workpiece wherein the arc is used to melt a filler material at the welding point or region. During the welding process, the welding region may be protected by an inert or semi-inert gas referred to as a shielding gas. To produce the electric arc, the welding power supply is connected to the electrode and a ground lead is connected to a workpiece to create an electric circuit. Electrodes utilized in arc welding may be either consumable or non-consumable. Generally in arc welding processes comprising consumable electrodes, the electrode material is the filler material deposited at the weld. Examples of arc welding processes comprising use of consumable electrodes include shielded metal arc welding (SMAW), gas metal arc welding (GMAW), and submerged arc welding (SAW). For arc welding processes comprising non-consumable electrodes, addition of a filler material is required for the welding process. Examples of arc welding processes comprising non-consumable electrodes include gas tungsten arc welding (GTAW), also referred to as tungsten inert gas (TIG) welding, and a plasma arc welding. 
         [0005]    Use of arc welding for production and fitting of pipe is known. Depending upon the application, the pipe sections or workpieces may be in a horizontal position, an inclined position, or a vertical position. Regardless of the pipe position, the weld region generally consists of the entire circumference of the pipe. In order to access the entire weld region it may be necessary to rotate either the pipe or the welding machinery during the welding process. With respect to rotation of the pipe, the pipe sections may be rotated by placing the pipe onto automated rollers/rotators, which rotate the pipe at a controlled rate during the welding process. Alternatively, pipe welding processes may comprise use of a motorized welder, which is guided on a track that has been fitted around the circumference of the pipe, thereby allowing the welding machinery to move around the circumference of the stationary pipe. 
         [0006]    These approaches are not without drawbacks. For example, automated rollers are generally costly and require maintenance. Special lifting machinery may be required to position the pipe onto the rollers. In addition, the majority of roller apparatus are heavy and thus not readily portable from one job site/weld site to another. With respect to motorized welders, these are generally costly and require maintenance. Accurately fitting and positioning the guide tracks onto the circumference of the pipe at the weld region can also be a difficult and time consuming process. 
         [0007]    Additionally, with the rotation of the pipe, the electrical power cord connect to the pipe with generally become wrapped around the pipe as the pipe rotates. 
         [0008]    Despite advancements in the art, access to the weld region by welding machinery remains a challenge in pipe fitting applications. Apparatus and methods for arc welding pipe that do not suffer from the limitations of the prior art have not been described. 
         [0009]    Thus, there is a need in the art for arc welding apparatus that provide proper positioning of workpieces. 
         [0010]    There is another need in the art for pipe welding positioning apparatus that are portable and easy to operate. 
         [0011]    There is even another need in the art for methods for arc welding pipe sections. 
         [0012]    These and other needs in the art will become apparent to those of skill in the art upon review of this specification, including its drawings and claims 
         [0013]    The present disclosure may provide methods, apparatus and/or products for the welding of rotating work pieces. 
       SUMMARY OF THE INVENTION 
       [0014]    The following presents a general summary of some of the many possible embodiments of this disclosure in order to provide a basic understanding of this disclosure. This summary is not an extensive overview of all embodiments of this disclosure. This summary is not intended to identify key or critical elements of the disclosure or to delineate or otherwise limit the scope of the claims. The following summary merely presents some concepts of the disclosure in a general form as a prelude to the more detailed description that follows. 
         [0015]    According to one embodiment of the present invention, there is provided an arc welding tool. The tool may include a circular frame defining a passage for receiving a work piece. The tool may also include a carriage moveably positioned on the frame. The tool may also include an electrical connector supported by the carriage, with an electrical path defined between the frame, carriage and electrical connector. 
         [0016]    According to another embodiment of the present invention, there is provided a system for arc welding a work piece. The system may include an electrical power source. The system may also include a welding rod in electrical communication with the power source for contacting with the work piece. The system may also include a circular frame defining a passage for receiving the work piece. The system may also include a carriage moveably positioned on the frame. The system may also include an electrical connector supported by the carriage, with an electrical path defined between the frame, carriage and electrical connector. When a work piece is received within the circular frame and the welding rod is in contact with the work piece, an electrical path is defined through the electrical power source, the welding rod, the work piece, the frame, the carriage, the electrical connector, to ground. 
         [0017]    According to even another embodiment of the present invention, there is provided a method of arc welding. The method may include rotating a work piece to be welded, wherein the work piece supports a circular frame, with a carriage movably connected to the frame, with the carriage connected to ground, and wherein the track and the work piece rotate past the carriage during rotation. The method may also include contacting the work piece with a welding rod to which electrical power has been provided. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    The following drawings illustrate some of the many possible embodiments of this disclosure in order to provide a basic understanding of this disclosure. These drawings do not provide an extensive overview of all embodiments of this disclosure. These drawings are not intended to identify key or critical elements of the disclosure or to delineate or otherwise limit the scope of the claims. The following drawings merely present some concepts of the disclosure in a general form. Thus, for a detailed understanding of this disclosure, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals. 
           [0019]      FIG. 1  is a view of elongated tubular work piece  25  (a pipe in the embodiment as shown) on which is positioned electrode connector  100 . 
           [0020]      FIG. 2  is a detailed view of electrode connector  100 , that includes track  102  on which is suspended connector carriage  103 . 
           [0021]      FIG. 3  is a side view of track  102  in the closed position. 
           [0022]      FIG. 4  is a side view of track  102  in the open position. 
           [0023]      FIG. 5  is a detail view of connector carriage  103 . 
           [0024]      FIG. 6  shows track  102  being inserted beneath rollers  110  of connector carriage  103  during assembly. 
           [0025]      FIG. 7  is a downward view of connector carriage  102  suspended beneath track  102 . 
           [0026]      FIG. 8  is a schematic showing electrode connector  100  positioned on work piece  25 , which is connected through conductive path  105  to ground  307 , with electrical power provided from welding machine  301  through conductive path  303  to welding rod  302 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    Referring first to  FIG. 1 , there is shown a view of elongated tubular work piece  25  (a pipe in the embodiment as shown) on which is positioned electrode connector  100 . Rotating table  30  includes a plurality of powered wheels  31 , which both support work piece  25  and rotate work piece  25  during welding. The rate of rotation of wheels  31  may be controlled to accommodate any welding scheme. 
         [0028]    Referring additionally to  FIG. 2 , there is shown more detail of electrode connector  100 . Specifically, electrode connector  100  includes a frame or track  102  on which is suspended connector carriage  103 . Connector carriage  103  includes a plurality of wheels  110  which allow connector carriage  103  to be suspended from track  102 . Cable  105  provides a ground for the current from an arc welding machine or other electrical power source. Cable  105  may be integral to connector carriage  103 , or may be connected to connector carriage  103  at connector  107 . The other end of cable  105  may be connected to a ground. The frame or track  102  defines a passage for receipt of work piece  25  During rotation of work piece  25 , track  102  will move along with work piece  25 , while wheels  110  will allow connector  103  to remain suspended underneath work piece  25 . As another was of looking at it, during rotation of work piece  25 , work piece  25  and track  102  will move past carriage  103 . Depending upon the speed of rotation, frictional forces, and other factors, connector carriage  103  may move in the direction of rotation, although it is unlikely that connector carriage  103  would make more than just a partial rotation, and would most likely swing back underneath work piece  25  in a pendulum motion fashion. A carriage movement restrictor, such as frame  50  may optionally be provided in the travel path of carriage  103  to restrict such movement of connector carriage  103 . This frame  50  is easily moveable to be as close to carriage  103  as necessary. 
         [0029]    Referring additionally to  FIGS. 3 and 4 , there are shown side views of track  102  in the closed and opened positions, respectively. Track  102  may further include any number of reinforcing members  135 , which is shown as being connected to track  102  by a plurality of stabilizer bars  133 . Certainly, track  102  may be designed for a specific diameter of work piece. Alternatively, diameter adjustment members  121 , may be provided to allow track  102  to be placed around work pieces of a range of diameters. These diameter adjustment members  121  are threaded and reside in threaded ports  122 . Rotation of diameter adjustment members  121  will move those members inward or outward to adjust the diameter of work piece  25  which may be received. 
         [0030]    Track  102  may be one continuous piece that is slipped over the end of work piece  25 . Alternatively, track  102  may comprise two or more pieces which may be assembled around work piece  25 . In the embodiment as shown, track  102  comprises two pieces  102 A and  102 B that are joined by hinge  125 . Connector members  127  and  128 , which in the embodiment shown are two pieces of an interlocking latch, lock track  102  in place around work piece  25 . Certainly, any suitable connector system may be utilized. 
         [0031]    Referring additionally to  FIG. 5  there is shown connector carriage  103 . A plurality of rollers  110  allow connector  103  to move along track  102  and remain suspended underneath work piece  25 . 
         [0032]    Referring additionally to  FIGS. 6 and 7 , there is shown connector carriage  103  and track  102 . As shown in  FIG. 6 , during assembly track  102  is inserted beneath rollers  110  of connector carriage  103 . Subsequently, track  102  is positioned around work piece  25  and secured in place with connectors  127  and  128 .  FIG. 7  is a downward view of connector carriage  102  suspended beneath track  102 . 
         [0033]    Electrode connector  100  is sufficiently conductive to allow for an electrical travel path from the power source to work piece  25 . Generally the electrical travel path will be through connector carriage  103 , through wheels  110 , through track  102 , through diameter adjustment members  121 , to work piece  25 . Generally, there are a sufficient number of diameter adjustment members  121  to allow for efficient current flow to work piece  25 . 
         [0034]      FIG. 8  is a schematic showing electrode connector  100  positioned on work piece  25 , which is connected through conductive path  105  to ground  307 , with electrical power provided from welding machine  301  through conductive path  303  to welding rod  302 . 
         [0035]    In operation, diameter adjustment members  121  are positioned suitable for the diameter of work piece  25 . Track  102  is then inserted into position beneath rollers  110  of connector carriage  103 . Track  102  is then assembled around work piece  25 . During rotation of work piece  25 , track  102  will rotate in conjunction with work piece  25 . Connector carriage  103  will remain relatively beneath work piece  25  as rollers  110  allow track  102  to move relative to carriage  103 . Frame  50  may optionally restrict movement of carriage  103 . Power is provided from welding machine  301  to welding rod  302 , with work piece  25  being grounded through electrode connector  100 . 
         [0036]    Various embodiments of methods of the present invention may include any one or more of the following: attaching the connector of the present invention to a work piece; connecting the connector to ground; rotating the work piece; and contacting the rotating work piece with a welding rod connected to an electrical power source. 
         [0037]    The present disclosure is to be taken as illustrative rather than as limiting the scope or nature of the claims below. Numerous modifications and variations will become apparent to those skilled in the art after studying the disclosure, including use of equivalent functional and/or structural substitutes for elements described herein, use of equivalent functional couplings for couplings described herein, and/or use of equivalent functional actions for actions described herein. Any insubstantial variations are to be considered within the scope of the claims below.