Patent Description:
In an arc welding apparatus, such as Metal Inert Gas (MIG) or Gas Metal Arc Welding (GMAW) welding gun, a welding wire is fed through the welding gun to provide a molten metal pool to join metal work pieces together. An inert gas is directed through the front (distal) end of the welding gun to provide a surrounding layer or blanket of shielding gas to protect the molten metal pool from atmospheric contamination. The inert gas is typically a combination of various gases such as argon or helium, among others.

A prior art MIG or GMAW welding gun typically includes a contact tip and a gas diffuser connected to the contact tip. The contact tip has a central bore to guide the welding wire to the work pieces. The contact tip transfers electrical current to the welding wire. The contact tip is typically threaded into the gas diffuser and the gas diffuser defines gas passageways that direct the shielding gas around the contact tip. The contact tip and gas diffuser are constantly subjected to high heat and are susceptible to wear due to high temperature operation. A nozzle assembly surrounds the contact tip and gas diffuser. The nozzle assembly further directs the shielding gas towards the work pieces to blanket the molten metal pool.

<CIT> discloses a welding gun having a removable end portion. The end portion may be adapted to direct gas from the welding gun. The end portion may be conical-shaped. The end portion may be removed without tools. The end portion also may be adapted to be secured to and/or removed from the welding gun in a linear movement. A method of assembling a welding gun. The method may comprise urging a nozzle end member and a nozzle body into engagement to secure the nozzle end member to the nozzle body.

<CIT> discloses an adjustable slip-fit welding nozzle that enables very fine adjustments to be made to the dimensional relationship between a nozzle orifice and a welding contact tip of a wire welding gun.

The present disclosure generally provides a nozzle assembly for a welding torch that comprises a nozzle body having an internal bore with a plurality of detents disposed within a portion of the internal bore and an insert assembly having a proximal exterior surface with a plurality of sealing members. The insert assembly is adapted to be secured within the internal bore of the nozzle body by the plurality of sealing members progressively engaging the plurality of detents. A nozzle assembly according to the invention is defined in claims <NUM>, <NUM> and <NUM>. Further optional features are defined in the dependent claims.

Although the term "MIG" and "GMAW" are used within the specification, it should be understood that the teachings of the present disclosure apply to any type of welding or cutting apparatus.

Referring to <FIG>, an arc welding apparatus, such as a MIG or GMAW welding gun, is illustrated and generally indicated by reference numeral <NUM>. The MIG welding gun <NUM> includes a handle <NUM>, a conductor tube <NUM> attached to the handle <NUM>, and a consumable assembly <NUM> attached to the conductor tube <NUM>. The handle <NUM> is connected to a welding cable <NUM> that carries welding current, shielding gas, and a welding wire <NUM> from a power source (not shown), a gas source (not shown), and a wire feeder (not shown) to the welding gun <NUM>.

The consumable assembly <NUM> includes a plurality of consumable components including a nozzle assembly <NUM> and a contact tip <NUM>. The structure and operation of an exemplary arc welding apparatus has been disclosed in <CIT> and <CIT>, which are commonly owned by the assignee of the present application, and the contents of which are incorporated herein by reference in their entirety. In addition, the structure and operation of the arc welding apparatus <NUM> incorporating a contact tip that provides for the function as a contact tip and a diffuser has been disclosed in related <CIT>, which is commonly owned by the assignee of the present application, and the contents of which are incorporated herein by reference in their entirety.

Referring to <FIG>, the consumable assembly <NUM> is connected to a distal end portion <NUM> of the conductor tube <NUM>. A nozzle assembly <NUM> is substantially cylindrical in one form and receives the distal end portion <NUM> of the conductor tube <NUM> therein. In one form, a contact tip <NUM> is coaxially disposed inside the nozzle assembly <NUM>, which has a seating surface <NUM> that is configured to mate with an end portion <NUM> (which in one form is spherical as shown, but could be any shape including a linear or polynomial taper) of the contact tip <NUM> into the distal end portion <NUM> of the conductor tube <NUM>.

In one form the nozzle assembly <NUM> is secured onto the distal end <NUM> of the conductor tube assembly <NUM>, and the contact tip <NUM> engages the seating surface <NUM> of a nozzle insert <NUM>. As the nozzle assembly <NUM> is tightened onto the conductor tube assembly <NUM>, the seating surface <NUM> engages against a shoulder <NUM> of the contact tip <NUM>, thereby urging the spherical tapered end <NUM> of the contact tip <NUM> into the spherical tapered seat <NUM> of the conductor tube <NUM>. The nozzle insert <NUM> tightens onto the conductor tube assembly <NUM> and the spherical tapered end <NUM> of the contact tip <NUM> is secured into engagement with the tapered seat <NUM>.

The conductor tube <NUM> defines an internal passageway <NUM>, and a conduit liner <NUM> is disposed within the internal passageway <NUM> as shown. The conduit liner <NUM> has a guiding channel <NUM> for guiding the welding wire <NUM> (not shown) to the contact tip <NUM>. The conduit liner <NUM> may extend into an internal cavity <NUM> of the contact tip <NUM>. The positioning of the conduit liner <NUM> within the internal cavity <NUM> provides a continuous guiding channel <NUM> for directly feeding the welding wire into the contact tip <NUM>. Proper positioning of the conduit liner <NUM> within the contact tip <NUM>, or "stick-out" relative to the distal end portion <NUM> of the conductor tube <NUM>, is a factor for the correct operation of the welding torch <NUM>. The conduit liner <NUM> directs the welding wire <NUM> through the welding cable <NUM>, torch <NUM>, conductor tube <NUM>, and into the contact tip <NUM>.

Additional aspects of the location and features of the conduit liner <NUM> within the internal cavity <NUM> of the contact tip <NUM> has been disclosed in <CIT>, which is commonly owned by the assignee of the present application, and the contents of which are incorporated herein by reference in their entirety.

Referring to <FIG>, the conductor tube <NUM> can define a variety of geometries, and, a curved geometry of various degrees is used depending on the application requirements. The conductor tube <NUM> alternatively could be straight or flexible and configurable as has been disclosed in <CIT>, which is commonly owned by the assignee of the present application, and the contents of which are incorporated herein by reference in their entirety. The conductor tube assembly <NUM> extends a length between its distal end <NUM> and its proximal end <NUM>. The proximal end <NUM> is adapted to be secured to the handle <NUM> of the welding gun <NUM>, and the distal end <NUM> of the conductor tube <NUM> is adapted to receive the consumable assembly <NUM> (as shown in <FIG>).

The distal end <NUM> of the conductor tube <NUM> provides unique features to allow for an efficient and robust connection with the consumable assembly <NUM>, the nozzle assembly <NUM>, and the contact tip <NUM>. For example, in one form, the distal end <NUM> has an outer surface <NUM> that includes two opposing flat faces <NUM>, that allows for an anti-rotational engagement with a sleeve (not shown). Additionally, in another form, the distal end <NUM> has a threaded opening <NUM> through at least one of the flat faces <NUM> for securing the sleeve.

The conductor tube <NUM> is typically made from a copper alloy or other metal that has conductive properties and then is coated with an insulation material <NUM>, which in one form may be silicone, and finally covered with a tube jacket <NUM> to provide durability and additional insulation from the electric current, which flows through the conductor tube <NUM> during operation of the welding gun <NUM>. The tube jacket <NUM> by way of example may be made from a brass or stainless steel metal or alloy in one form of the present disclosure.

As shown in <FIG>, the conductor tube <NUM> is a hollow member defining the internal passageway <NUM>. The internal passageway <NUM> includes a tailored cavity <NUM>. The tailored cavity <NUM> is shaped to receive an alignment device (not shown in this figure), which in one form is press-fit therein. In addition, the internal passageway <NUM> at the distal end <NUM> includes a spherical tapered seat <NUM> forming a contact surface that engages with the contact tip <NUM>.

<FIG> summarizes and illustrates components of the conductor tube assembly <NUM> and the consumable assembly <NUM>. The consumable assembly <NUM> includes the nozzle assembly <NUM> and the contact tip <NUM>. The consumable assembly <NUM> is secured to the distal end <NUM> of the conductor tube <NUM> via the sleeve <NUM>, and the collar assembly <NUM> pretensions the consumable assembly <NUM> to the conductor tube assembly <NUM> as previously set forth.

The contact tip <NUM> has a body that defines an internal cavity extending from its proximal end portion to its distal end portion. Advantageously, the contact tip <NUM> is designed to function as both a contact tip for transferring electric current to the welding wire and a gas diffuser for diffusing shielding gas around the molten metal pool, thus providing a dual function while eliminating an additional component (i.e., a separate gas diffuser) from the consumable assembly <NUM>.

Referring to <FIG> and <FIG>, the nozzle assembly <NUM> includes a nozzle body <NUM> that is in one form generally cylindrical, an insulator <NUM>, and a nozzle insert <NUM>. As shown, the outer nozzle <NUM> extends from a proximal opening <NUM> to a distal opening <NUM>. The nozzle body <NUM> may further include a nose portion <NUM> that narrows or extends inwardly to properly direct the shielding gas for a given application in relation to maintain the desired space <NUM> (<FIG>) for the contact tip <NUM>. The nozzle insert <NUM> has a proximal end portion <NUM> and a distal end portion <NUM> and includes a central bore <NUM> extending from the proximal end portion <NUM> towards the distal end portion <NUM>. The nozzle insert <NUM> at its distal end portion <NUM> defines an internal gas diverter <NUM>. The internal gas diverter <NUM> further defines a seating surface <NUM> toward the proximal end portion of the nozzle insert <NUM>. The seating surface <NUM> is chamfered in one form, for engaging the angled shoulder <NUM> of the contact tip <NUM>. The internal gas diverter <NUM> defines a profiled diverter orifice <NUM> that extends distally from the central bore <NUM>.

As shown in <FIG>, the profiled diverter orifice <NUM> extends around the apertures <NUM> of the contact tip <NUM>. The gas flow, indicated by the path arrows <NUM>, is directed distally through the internal cavity <NUM>, and then radially outwards through the apertures <NUM>. The profiled diverter orifice <NUM> then directs the gas flow exiting the apertures <NUM> distally around an exterior portion of the contact tip <NUM> as shown. The profiled diverter orifice <NUM> may extend various lengths from the contact seat <NUM> (as shown in <FIG>) and include a variety of geometries, in addition to the chamfered configurations as illustrated herein. In addition, the profiled diverter orifice <NUM> may extend at any angle that will change the direction of the shield gas to improve the flow characteristics or cooling of the contact tip <NUM> and surrounding nozzle assembly <NUM>. For example, to generate a laminar flow along the length of the contact tip <NUM>.

The nozzle insert <NUM> may be manufactured by various methods including machining or a metal injection molding process, also known as MIM. In addition, the nozzle insert may be made from various metals and alloys, for example, in one form the nozzle insert <NUM> is made of brass.

According to one aspect of the present disclosure, a nozzle assembly is provided that comprises an insulator having a plurality of grooves around an outer periphery. The insulator has a plurality of sealing members disposed within the grooves of the insulator, and a nozzle body slip-fit around the insulator.

Referring now to <FIG>, <FIG>, in a non-claimed example, the nozzle assembly includes a nozzle body <NUM> that is slip-fit around an insulator <NUM>. As shown in <FIG>, the insulator <NUM> and a nozzle insert <NUM> define an assembly and are secured to the sleeve <NUM> on the conductor tube assembly <NUM>. In one form, the insulator <NUM> is secured around the nozzle insert <NUM>. As further shown in <FIG>, the insulator <NUM> includes a plurality of grooves <NUM> around its outer periphery. The grooves <NUM> are used for locating and seating sealing members <NUM>, which provide a sealing engagement between the nozzle body <NUM> and the insulator <NUM>. In one form, the sealing members <NUM> are spring rings that are located within the grooves <NUM>. Although the insulator <NUM> is illustrated with three (<NUM>) grooves <NUM>, it should be understood that a greater or fewer number may be used depending on the application and the length of the nozzle body <NUM>, among other operating parameters.

The consumable components are typically, rated to a duty cycle. The duty cycle is usually determined by the duration of the weld operation and the amperage used during continuous operation of the welding gun. For example, a light duty application may be considered to be those welding operations that are rated and use approximately <NUM> amperes and below. A medium duty application may be considered to be welding operations with a range from approximately <NUM> amperes to approximately <NUM> amperes, and a heavy duty application is generally <NUM> amperes and above.

Referring to <FIG>, according to the invention, a nozzle assembly <NUM> for a light duty application. The nozzle assembly <NUM> comprises a nozzle body <NUM> and an insulator <NUM>. The insulator <NUM> may be over molded onto the nozzle body <NUM>. As further shown, the insulator <NUM> defines an internal bore <NUM> having a plurality of detents <NUM> at a proximal end portion <NUM>. The detents <NUM> are a series of grooves that are spaced along the internal bore <NUM> to progressively engage sealing members <NUM>. The user can adjust the relative position of the nozzle with the distal end of the contact tip <NUM> depending on the engagement between the detents <NUM> and the sealing members <NUM>.

The insulator, whether a plastic material or other insulator, has a high strength, hardness and rigidity to provide for durability of the nozzle body <NUM> and the detents <NUM>. For example, the over molded insulator <NUM> may be made from a thermoset polyester, such as BMC <NUM>. However, it is appreciated that the insulator <NUM> may be any insulating material that can withstand the amperage for the duty cycle of the welding application.

Referring to <FIG>, another form of a nozzle assembly <NUM> according to an embodiment of the invention for a light duty application is shown. The nozzle assembly <NUM> comprises a nozzle body <NUM>, an insulator <NUM>, and a nozzle sleeve <NUM>. In this form, the nozzle assembly <NUM> is assembled together by a crimping process to secure the insulator <NUM> and the nozzle sleeve <NUM> within the nozzle body <NUM>. The nozzle sleeve <NUM> defines an internal bore <NUM> of the nozzle body <NUM>. The internal bore <NUM> further defines a plurality of detents <NUM> at a proximal end portion <NUM>. The nozzle sleeve <NUM> may be a made of various materials including metals such as a copper alloy, brass alloy, or alternately plastic materials. Other materials may be used as long as the material and withstand the heat of the application and the amperage needed for the specific welding application. For example, in a light duty application is generally between <NUM> to <NUM> Amperes.

An insert assembly <NUM>, in one form, is the same for both forms of the nozzle body <NUM>, <NUM> of the light duty applications. The insert assembly <NUM> has a proximal exterior surface <NUM> with a plurality of groove <NUM>, and a plurality of spring bands <NUM>. The spring bands in this form are split ring metal seals that provide an outward bias and engage into the detents to provide a user with a haptic feedback on the position of the nozzle assembly. The spring bands also provide a bias force to secure the nozzle assembly <NUM>, <NUM> to the insert assembly <NUM>. The insert assembly <NUM> is threaded onto the conductor tube (not shown) and secures the contact tip <NUM> to the conductor tube (not shown). The insert assembly <NUM> for the light duty applications has two grooves <NUM> each for retaining a spring band <NUM>. The nozzle bodies <NUM>, <NUM> define three detents <NUM> that secure the nozzle body <NUM>, <NUM> in three positions relative to a distal opening of the nozzle body and the contact tip. The nozzle body slides and locks the detents into positions relative to the contact tip for adjusting the flow characteristics of the shield gas to accommodate a wide variety of welding parameters and user preferences.

Referring now to <FIG> and <FIG>, another embodiment of the invention for medium and heavy duty applications is described. The nozzle assembly may be scaled and sized to accommodate a variety of diameters of welding wire and consumables components. It is also appreciated that the materials may vary depending on the duty cycle and the amperage rating. In this form, the nozzle assembly <NUM> includes a nozzle body <NUM>. The nozzle body <NUM> may be a singular metal component, typically a copper alloy, but may be formed of various other metals and alloys, among other temperature and durability capable materials, while remaining within the scope of the present disclosure. The nozzle body <NUM> has an internal bore <NUM> with a plurality of detents <NUM> within a portion <NUM> of the internal bore <NUM>.

The medium and heavy duty applications may also include in an alternate form an insert assembly <NUM> that includes a nozzle insert <NUM>, insulator <NUM> and a slip adapter <NUM>, which are secured together in one form by a crimping process. However, it should be understood that various processes may be used to secure the components of the insert assembly <NUM> while remaining within the scope of the present disclosure. The slip adapter <NUM> defines a proximal exterior surface <NUM> with a plurality of grooves <NUM>, and a plurality of spring bands <NUM>. The spring bands <NUM> in this form include a split spring ring, as in the previous forms and a spring metal band <NUM>. The grooves <NUM> may vary in width to accommodate the spring band <NUM>. And the spring bands <NUM> may be customized, such as by way of example, a metal band <NUM> that defines circumferentially spaced protrusions <NUM>. The metal band provide the biased outward force and the protrusions <NUM> are designed to engage within the plurality of detents <NUM> of the internal bore <NUM> of the nozzle body <NUM>. During adjusting of the nozzle body <NUM> the protrusions <NUM> provide tactile feedback and assist the user with locating the nozzle body <NUM> at the desired location relative to the distal end of the contact tip (not shown).

Claim 1:
A nozzle assembly (<NUM>) for a welding torch comprising:
a nozzle body (<NUM>) surrounding an insulator (<NUM>), the insulator (<NUM>)
having an interior surface defining an internal bore (<NUM>) with a plurality of
detents (<NUM>) disposed along the interior surface within a portion of the internal bore (<NUM>); and
an insert assembly (<NUM>) having a proximal exterior surface (<NUM>) with a plurality of sealing members (<NUM>);
wherein the insert assembly (<NUM>) is adapted to be secured within the internal bore (<NUM>) of the insulator (<NUM>) of the nozzle body (<NUM>) by the plurality of sealing members (<NUM>) progressively engaging the plurality of detents (<NUM>).