Patent ID: 12233492

The various embodiments described herein are not intended to limit the invention to those embodiments described. On the contrary, the intent is to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the welding torch and adjustable electrode receiver as defined by the appended claims.

DETAILED DESCRIPTION

Referring now to the drawings where the showings are for the purpose of illustrating a preferred embodiment of the removable torch head with an adjustable electrode receiver. As will be appreciated, the disclosed welding torch head is one part of a gas tungsten arc welding system. In one embodiment such a welding system includes a power supply, an inert gas supply, a water/liquid cooler and a torch assembly including a torch head100as depicted inFIG.2, for example. In practice, a workpiece (not shown) is electrically connected to the power supply to provide either −DC, +DC or AC through a clamp and a return cable electrically connected to the workpiece (not shown). Torch100provides means for delivering the inert gas as well as an arc formed within an air gap between the tip of the tungsten electrode120and the work piece, where the arc is sufficient to generate the heat required to fuse the work pieces together. Torch100may be further connected to a water or chilled liquid supply for cooling of the torch when a high current and/or an extended duration welding operation is performed.

The operative mechanical elements of the adjustable electrode receiver reside within a housing of the torch100, particularly a torch handle108to which a removable torch head110is attached. As illustrated in the figures, the removable torch head110includes a hollow plunger114adapted to fit the torch body (see e.g.,FIG.1) and having a first end116for threadable connection to welding torch100. A second threaded end118of the plunger is for coupling to and interacting with the torch head body130. When attached to the welding torch, for example as depicted inFIGS.1and5, the hollow plunger114extends outward and provides a stem over which a surrounding nozzle seat126can be operatively connected about the exposed threaded end118of the plunger. In order to permit use of the removable torch head110, end116of the hollow plunger114must be suitable for threaded connection to a conventional torch. While depicted inFIG.1with at least two different torch types, such as an WP17 torch and a WP20 torch, it will be appreciated that the removable torch head disclosed herein may be suitable for use with other torches as well. Although not specifically illustrated, it will be appreciated that the rear or back end of the torch typically includes a tailpiece that encloses that portion of the electrode extending through the removable head.

The nozzle seat126and the nozzle128may be made of a number of materials suitable for high-temperature use, such as machinable or molded ceramic or Pyrex® materials or high-temperature plastics such as glass-filled polytetrafluoroethylene (PTFE) or Teflon®. The inert gas, supplied to the torch and into the removable torch head110, flows through the hollow interior of plunger114, where the gas is then directed into the torch head body130and nozzle128, and then out around the electrode in the region of an electrical arc extending between the work piece and the electrode.

As depicted for example inFIGS.3-4, the nozzle128is associated with the torch body and nozzle seat126, and is removably affixed to the nozzle seat and torch head body130by friction fit thereto. As an alternative to the friction fit between the nozzle seat and the nozzle, also contemplated is a threaded connection or a bayonet-type connection therebetween. Moreover, in one embodiment the friction fit with the torch body may be provided via O-rings124or similar elements encircling the torch body, for example an O-ring within O-ring retaining groove122as depicted inFIG.9.

Referring also toFIG.18, the removable torch110head also includes a torch head body130that includes a tapered interior region134, a plurality of apertures138to permit gas flow therethrough, and a threaded inside diameter142to permit the operative engagement (e.g., threadable) of a chuck back plate146thereon. The chuck back plate146has, in one embodiment, a threaded outer diameter for engaging the threaded inner diameter of the torch body. Also within removable head130are at least two and typically at least three or more radially positioned electrode securing wedges (jaw pieces)154forming an electrode aperture therebetween within the tapered interior region of the torch body such that each securing wedge can traverse or slide, in unison, along the conical interior surface of the tapered region134in a longitudinal direction to form a variable aperture (jaw) therebetween. The securing wedges154being further contacted on an end thereof by a plunger thrust cup160. The thrust cup160, in further combination with the plunger114and back plate146, translate rotation of the plunger relative to the back plate into linear motion of the thrust cup in contact with the electrode securing wedges, and further provide a clamping motion of the electrode securing wedges against the electrode120as a result of their sliding contact with the tapered surface.

In operation, electrode120is inserted along the interior surface of wedges154and clamped therein by a force applied to the interior ends of the wedges by plunger thrust cup160. In the depicted embodiment, a compressive force is provided to the thrust cup160by plunger114being rotated relative to the torch head body130, thereby advancing the wedges154in response to the rotation of the head and closing the jaw formed by the wedges about the electrode. When the plunger is rotated in the opposite direction, the plunger is retracted relative to the head body130, and as a result the pressure applied to the wedges is removed. In the absence of pressure from the plunger114the electrode wedges120, under the force of biasing member (spring)164, slide up the jaw to expand or open the jaw. In other words, as the plunger114backs away from the thrust cup the biasing springs164force the electrode wedges apart, causing the wedges to slide the jaws back up and outward along the inner cone and keeping them against the thrust cup. There is no pulling action of the plunger or thrust cup, but the biasing force causes the wedges to move to the largest diameter position. The springs just keep everything under tension and moving in the cone during retraction. In the unlikely event that the wedges are temporarily “fixed” in one position, a slight tap with the tungsten electrode causes them to snap back and continue moving for retraction, but typically they slide back.

The rate of change of the orifice diameter formed by wedges154is a function of the pitch of the thread, or turns per inch (TPI) on the mating surfaces of the chuck backing plate146and end118of the hollow plunger114, as well as included angle Θ or slope, of the posterior surface162of the wedge154. The corresponding interior conical surface134shares a common slope angle Θ, typically in the range of 15-20 degrees. Consequently, the minimum and maximum aperture diameter is a function of the sine of angle Θ.

Furthermore, to assure that the electrode securing wedges154remain spaced apart when not being compressed against an electrode, each of the electrode securing wedges is biased away from an adjacent wedge, and toward the conical interior surface of the tapered region, by at least one biasing member164between adjacent wedges. In one embodiment the biasing members are compression springs made of stainless steel and seated in recesses142in each of the planar surfaces168of the electrode securing wedges154. As will be appreciated, the resilient members164(e.g., coil compression spring) associated with each of the electrode securing wedges, biases the wedges toward the conical interior surface of the tapered region134. It will be further appreciated that while the resilient members164are depicted as lying between adjacent wedges154, or more particularly recesses142on the wedges, it is also possible to provide other wedge and spring configurations that bias the wedges so they tend to move outward (and therefore toward the larger diameter of the housing).

In summary, in the torch head body130of the adjustable electrode receiver, the electrode securing wedges154each include adjacent planar surfaces sharing a first edge or transition line156therebetween and each having an opposite edge158spaced away and slightly angled relative to the first edge, and a conical surface (162, rear of wedge inFIG.16) spanning between the opposite edges of the planar surfaces168, and where at least one of the planar surfaces includes an aperture therein (to receive an end of the coil compression spring164). As will be further appreciated, the transition line156, between adjacent planar surfaces of the electrode securing wedge, provides a continuous region (e.g., along the line) for contact between the wedge and the electrode.

To assure the flow of electrical current through the torch head body130and into the wedges154and associated electrode129, the internal conical surface134remains in contact with each securing wedge over at least a portion if not all of the outer wedge surface, in order to reduce contact heating. In one embodiment the wedges are formed of an electrically conductive metal, such as an alloy—for example a steel alloy, a copper alloy (e.g., brass, bronze) or a nickel alloy. As illustrated inFIG.7, one embodiment employs three electrode securing wedges154in the head130. And, the securing wedges154further provide electrical contact between electrode120and the conical surface134of the torch body130. In the embodiments depicted, for example inFIGS.6.7and18, the radially positioned electrode securing wedges154within the torch head body130are able to receive an electrode diameter of at least about 0.145 inches or larger.

As previously noted, the nozzle128, encircles the torch body to direct the inert gas along and through the torch head and the nozzle is operatively attached at one end thereof to the nozzle seat126.

Referring next toFIGS.18-26, depicted therein are various illustrations of an alternative embodiment for the removable electric arc welding torch head. In this embodiment, as particularly depicted inFIGS.20,22and24, an external shoulder212is added to plunger114and a corresponding interior shoulder224, in region226, is added to nozzle seat126, to avoid the possibility of the nozzle seat126being inadvertently removed from the torch head when a user removes the outermost ceramic nozzle128. More specifically, the removable torch head110ofFIG.19includes a hollow plunger114adapted to fit the torch body. In this embodiment, however, plunger114includes a shoulder214that matches a corresponding shoulder224on the nozzle seat128to assure that the seat does not inadvertently come off the torch when the ceramic nozzle128is removed from the torch head100. Also illustrated inFIG.18is a tailpiece, at the rear or back end of the torch, which encloses the portion of the electrode (not shown) extending through the torch head.

A second feature of the alternative embodiment includes the ability to actuate the chuck without having to remove the ceramic nozzle. In the alternative embodiment, the chuck body and ceramic nozzle are modified to further include operatively interlocking features, such as keys and keyways, so the nozzle can actuate the chuck without removal. To illustrate this feature more specifically, attention is turned toFIGS.19,21,23,25and26. In the side perspective view ofFIG.19, for example, one of the operatively interlocking features is depicted. Nozzle head130is modified to include external structures such as keys200. The keys200are positioned at approximately every 90-degrees about the outer circumferential surface of the head and extend from an annular exterior shoulder202. The keys each have a generally rectangular cross-section, although the outermost surface and edges thereof may be radiused or angled slightly to facilitate the keys interlocking with the keyways when the nozzle128is slidably placed over the nozzle head130.

In accordance with the alternative embodiment,FIG.21depicts a cross-sectional view of ceramic nozzle128andFIG.23depicts an end view of nozzle128.FIG.21illustrates that the ceramic nozzle of the alternative embodiment includes corresponding keyways206on the interior thereof, and as clearly depicted in the end view ofFIG.23the keyways206are similarly spaced about the interior surface of the nozzle at approximately every 90-degrees. Each of the keyways206may be constructed in a manner such that some or all of the outer surfaces208are tapered (angled) or radiused as shown inFIG.23so that the corresponding keys200are easily aligned with and fit within the keyways, for example as depicted in the assembled views such as the cross-sectional assembly view ofFIG.25and the end view ofFIG.26.

As will be appreciated the rotation of the nozzle128relative to torch head130will result in the keys200engaging the keyways206, and thereby cause the head130to similarly rotate relative to the chuck plate of the torch as previously described, thereby causing the movement of the securing wedges along the interior tapered surface of the head130as shown and described above relative to the first embodiment. In other words, rotation of head130will likewise result in a corresponding change of force applied to the securing wedges so that the clearance between the wedges changes—rotation in one direction increases clearance and rotation in the opposite direction decreases clearance.

While the interlocking feature between the nozzle and torch head are depicted and described as a key and keyway combination, it will be appreciated that the position, shape, size and number of key/keyway pairs may be varied while remaining within the spirit and scope of the instant disclosure of an interlocking feature(s). Moreover, there may be alternative mechanisms that could be employed to provide the operative interlocking of such components, mechanisms such as pins, collars, (threaded or unthreaded) and the like.

In recapitulation, as illustrated in the figures, a removable torch head is provided with a variable sized electrode receiver is provided. A plurality of electrode securing wedges154are positioned radially within the torch head body130and form an aperture therebetween, where the aperture size is adjustable based upon the position of the wedges relative to an internal conical surface134within the body. Use of the disclosed embodiments is believed to result in improved productivity by at least eliminating the need to change collets when switching between various electrode diameters or shapes. Moreover, the replaceable head is easily installed and adapted for use with convention inert gas welding torches.

It will be appreciated that several of the above-disclosed embodiments and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also, various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the description above and the following claims.