Welding wire retraction system and method

A method and system for retracting welding wire is provided. One welding torch includes a handle configured to receive welding wire from a wire source and to direct the welding wire to a torch tip. The welding torch also includes a first switch coupled to the handle and configured to cause the welding wire to extend out of the torch tip to expose more wire when the first switch is actuated. The welding torch includes a second switch coupled to the handle and configured to cause the welding wire to retract into the torch tip to expose less wire when the second switch is actuated.

BACKGROUND

The invention relates generally to welding systems and, more particularly, to a method and system for retracting welding wire in a welding system.

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 feed, 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 being continuously fed during welding to provide filler metal and to ensure that arc heating is available to melt the filler metal and the underlying base metal.

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. Unfortunately, quite commonly more welding wire than desired may be provided to the welding torch causing the welding wire to extend too far out of the torch, such as if the trigger is depressed when no arc is ongoing. Thus, in such conditions, the welding wire is often cut to the desired length by the operator, using a wire cutting tool, or the welding wire is burned off on a non-essential area of a workpiece (or weldment), leaving a “whisker” or wire extending out of the workpiece. Therefore, welding wire may be wasted and welding efficiency may decrease due to the time needed to cut the welding wire. There is a need in the field for techniques that might provide alternatives to cutting excess welding wire when too much welding wire extends out of a welding torch.

BRIEF DESCRIPTION

In an exemplary embodiment, a welding torch includes a handle configured to receive welding wire from a wire source and to direct the welding wire to a torch tip. The welding torch also includes a first switch coupled to the handle and configured to cause the welding wire to extend out of the torch tip to expose more wire when the first switch is actuated. The welding torch includes a second switch coupled to the handle and configured to cause the welding wire to retract into the torch tip to expose less wire when the second switch is actuated.

In another embodiment, a welding system includes a welding power supply configured to provide welding power. The welding system also includes a welding torch having a trigger and configured to receive welding power from the welding power supply and to extend welding wire out of the welding torch when the trigger is pressed. The welding system includes a reverse switch configured to retract the welding wire into the welding torch when actuated.

In another embodiment, a method for retracting welding wire includes receiving an indication that a welding wire retraction switch is actuated. The method also includes sending a command to a wire drive to rotate the wire drive in reverse to retract welding wire from a torch based upon the received indication.

DETAILED DESCRIPTION

Turning now to the drawings,FIG. 1is a perspective view of an exemplary welding power supply10configured for use in a gas metal arc welding (GMAW) process or a flux cored arc welding (FCAW) process. The welding power supply10includes a housing12including a top panel14, a side panel16, and a front panel18. The top panel14may include a handle that facilitates transport of the welding power supply10from one location to another by an operator if desired. The side panel16includes a breakaway view illustrating a controller20configured to control operation of the welding power supply10. The front panel18includes a control panel22adapted to allow an operator to set one or more parameters of the welding process, for example, via knobs24(or buttons, touchscreens, etc.).

In certain embodiments, the welding power supply10includes 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 another embodiment, a separate wire feeder may attach to the welding power supply10(i.e., external wire feeder). Such a separate wire feeder may also include a wire drive and a wire spool.

A main electrical connector26couples to the welding power supply10via the front panel18. A cable28extends from the main connector26to a welding torch30configured to be utilized in a welding operation to establish a welding arc. The welding torch30includes a trigger32and a reverse switch34(or button). The trigger32initiates a welding operation and causes welding wire to be supplied to the welding operation by exposing welding wire when pressed. Furthermore, pressing the trigger32may cause a switch in the trigger32to be actuated. The reversing button34causes welding wire to be retracted into the torch when pressed (or 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 reversing button to retract welding wire into the spoolgun.

A second cable36is attached to the welding power supply10through an aperture in the front panel18and terminates in a clamp38that is adapted to clamp to the workpiece during a welding operation to close the circuit between the welding power supply10, the welding torch30, and the workpiece. During such an operation, the welding power supply10is 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.

FIG. 2is a schematic diagram of an embodiment of a welding system50employing a reverse switch. The welding system50powers, controls, and supplies consumables to a welding application. The welding system50includes a welding power supply52, a wire feeder54, a torch56, and a workpiece58. The welding power supply52receives primary power60from an input power source (e.g., the AC power grid, an engine/generator set, a battery, or other energy generating or storage devices, or a combination thereof), conditions the input power, and provides an output power to one or more welding devices in accordance with demands of the system50. The primary power60may be supplied from an offsite location (i.e., the primary power may originate from the power grid). Accordingly, the welding power supply52includes power conversion circuitry62that may include circuit elements such as transformers, rectifiers, switches, and so forth, capable of converting the AC input power to AC or DC output power as dictated by the demands of the system50(e.g., particular welding processes and regimes). Such circuits are generally known in the art.

In some embodiments, the power conversion circuitry62may be configured to convert the primary power60to both weld and auxiliary power outputs. However, in other embodiments, the power conversion circuitry62may be adapted to convert primary power only to a weld power output, and a separate auxiliary converter may be provided to convert primary power to auxiliary power. Still further, in some embodiments, the welding power supply62may be adapted to receive a converted auxiliary power output directly from a wall outlet. Indeed, any suitable power conversion system or mechanism may be employed by the welding power supply52to generate and supply both weld and auxiliary power.

The welding power supply52includes processing circuitry64, a user interface66, and control circuitry68. The processing circuitry64controls the operations of the welding power supply52and may receive input from the user interface66through which a user may choose a process, and input desired parameters (e.g., voltages, currents, particular pulsed or non-pulsed welding regimes, and so forth). The control circuitry68may be configured to receive and process a plurality of inputs regarding the performance and demands of the system50. Furthermore, the control circuitry68communicates with the processing circuitry64to control parameters input by the user as well as any other parameters. The control circuitry68may include volatile or non-volatile memory, such as ROM, RAM, magnetic storage memory, optical storage memory, or a combination thereof. In addition, a variety of control parameters may be stored in the memory along with code configured to provide a specific output (e.g., initiate wire feed, enable gas flow, etc.) during operation.

The welding power supply52may also include a valve70to modulate the amount of gas supplied to a welding operation. The valve70operates with signals from the control circuitry68. A gas supply72may provide shielding gases, such as argon, helium, carbon dioxide, and so forth. The gas flows from the welding power supply52to the wire feeder54through a cable74coupled between the welding power supply52and the wire feeder54. A lead cable76, which may be terminated with a clamp, couples the welding power supply52to the workpiece58to complete the welding circuit.

Data is communicated between the control circuitry68and an interface circuit78. The interface circuit78conditions the data from the control circuitry68for communication to other welding devices, such as the wire feeder54and a pendant. Data conditioned in the welding power supply52is communicated to the wire feeder54over a control cable80. Power may also be transmitted over the control cable80.

The conditioned data is received by the wire feeder54and converted by an interface circuit82to signals compatible with a control circuitry84of the wire feeder54. Further, the interface circuit82may receive signals from control circuitry84for transmission to the welding power supply52. The control circuitry84communicates with a processing circuitry86. Such a processing circuitry86controls the functionality of the wire feeder54and is powered via a power conversion circuitry88. The processing circuitry86may receive input from a user interface90through which a user may input desired parameters (e.g., voltages, currents, wire speed, and so forth). The wire feeder54includes a wire drive92that receives control signals from the control circuit84to drive rollers94. The rollers94feed wire96from a wire spool98to a welding operation via a first roller100and a second roller102. Shielding gas and welding power are supplied to the welding operation using one or more cables104.

During operation, a trigger on the welding torch56may initiate a weld, causing the wire drive94to rotate the rollers94in a forward direction to supply wire96for the weld, thereby exposing a greater amount of wire96. Furthermore, the welding torch56includes a reverse switch (or button)106. When pressed, the reverse switch106causes the wire drive94to rotate the rollers94in a reverse direction to retract wire96into the welding torch56, thereby exposing a smaller amount of wire96. Thus, welding wire96may move in a forward or reverse direction as illustrated by arrow108.

According to certain embodiments, the wire feeder54may include reverse switch110and/or the welding power supply52may include a reverse switch112. Thus, one or more of the welding torch56, wire feeder54, and welding power supply52may include a reverse switch to cause the wire drive94to rotate the rollers94in a reverse direction to expose a smaller amount of wire96. As may be appreciated, while performing a weld, a reverse switch may enable a welding operator to efficiently adjust the length of wire96extending out of the welding torch56without the need for additional tools.

FIG. 3illustrates an embodiment of the welding torch30ofFIG. 1. As discussed in relation toFIG. 1, the welding torch30includes the trigger32for initiating a weld and supplying wire to the weld and the reverse switch34for retracting wire into the welding torch30. Specifically, the trigger32and the reverse switch34are disposed on a handle120. A welding operator holds the handle120when performing a weld. At one end122, the handle120is coupled to the cable28where welding consumables are supplied to the weld. Welding consumables generally travel through the handle120and exit at an end124, which is disposed on the handle120at an end opposite from end122.

The welding torch30includes a neck126extending out of end124. As such, the neck126is coupled between the handle120and a nozzle128. As should be noted, when the trigger32is pressed or actuated, welding wire travels through the cable28, the handle120, the neck126, and the nozzle128, so that the welding wire extends out of an end130(i.e., torch tip) of the nozzle128. Furthermore, when the reverse switch34is pressed or actuated, the welding wire retracts into the nozzle128. The reverse switch34may be one of a variety of types of switches or buttons. For example, the reverse switch34may be a momentary contact switch which energizes an electrical circuit while pressed or another type of switch. In addition, the reverse switch34may be molded as part of the handle120, or the reverse switch34may be installed into an opening in the handle120. The reverse switch34may be constructed using any suitable material, such as a polymeric material.

Furthermore, the reverse switch34may send signals to control circuitry which controls the response to actuation of the reverse switch34. Specifically, control circuitry may retract welding wire for an unlimited amount of time while the reverse switch34remains actuated. In certain embodiments, control circuitry may retract welding wire for a predetermined amount of time, or a predetermined quantity of welding wire with each actuation of the reverse switch34. For example, the predetermined amount of time may be approximately 0.1 to 1.0 seconds, or any subranges therebetween. Likewise, the predetermined amount of time may be any suitable amount of time. As another example, the predetermined quantity of welding wire may be approximately 1/16″ to ¼″, or any subranges therebetween. Further, the predetermined quantity of welding wire may be any suitable quantity. In certain embodiments, actuating the trigger32inhibits the reverse switch34from being actuated, actuating the reverse switch34inhibits the trigger32from being actuated, or any combination thereof.

A connector132is coupled to cable28and during a welding operation connector132is connected to the welding power supply10depicted inFIG. 1. At least welding wire and welding power are transferred through the connector132. A second cable134extends from cable28and terminates with a connector136. Control signals from the trigger32and reverse switch34may be transmitted through cable134to control circuitry. As may be appreciated, before starting a weld, a welding operator may notice that more welding wire than desired extends out of nozzle end130. Therefore, the welding operator may actuate reverse switch34to retract welding wire into nozzle end130. For example, the welding operator may desire to have approximately ⅜″ of welding wire extend out of nozzle end130. Rather than using welpers to cut the wire, the welding operator may use reverse switch34to retract welding wire into the nozzle130.

FIG. 4is a break-away view of a portion of the welding torch30ofFIG. 3. As illustrated, the handle120is secured to the neck126via fasteners140and142, and to cable128via fasteners144and146. The nozzle128is illustrated with a portion of the nozzle128removed to show welding wire148extending out of a contact tip150. The welding wire148may extend or retract from the contact tip150as shown via arrow152. For example, during a weld, the welding wire148may extend out of the contact tip150a greater length than desired, such as illustrated by the broken lines depicting extended wire154. The length that a welding operator desires is a length156, while the extended wire154extends a length158greater than length156, or a total length160from the nozzle end130. For example, the welding operator may desire the length156to be approximately ⅜″. The total length160may be approximately ⅞″, therefore, the welding operator may use the reverse switch34to retract the welding wire into the contact tip150the length158(i.e., approximately ½″ in this example). As may be appreciated, the desired length156, total length160, and retracted length158may vary based at least on the type of weld being performed, and the excess amount of wire extending from the nozzle end130.

FIG. 5is a flow chart of an embodiment of a method170for retracting welding wire. At step172, a welding operator actuates a reverse switch. Next, at step174, control circuitry receives an indication that the reverse switch is actuated. For example, the indication may be a voltage change to a control circuitry input that is present as long as the reverse switch is actuated. Then, at step176, the control circuitry sends a command to rotate wire drive rollers in a reverse direction. The reverse direction is the opposite direction of rotation compared to the direction of roller rotation when performing a weld. In certain embodiments, the control circuitry may calculate a quantity of wire retracted while the rollers rotate, at step178. Such a calculation may be used by the control circuitry to limit the amount of wire retracted by the wire drive and may be based at least partly on the speed of rotation and the size of the rollers. At step180, the control circuitry may limit the duration of the command to the wire drive based at least partly on the quantity calculated at step178. In some embodiments, at step182, the control circuitry may limit the duration of the retraction command based at least partly on a predetermined amount of time that the command is sent. As may be appreciated, the method170may have a greater or lesser number of steps than described, and the steps may be performed in a different order.