WELD WIRE GUIDE CONDUIT

Abstract

A wire guide conduit is constructed from a coiled wire having an oval or elliptical cross-sectional shape. The wire is subjected to a directed energy beam to locally heat portions of the wire to create discrete areas of increased hardness in the surface of the wire. The wire is coiled to present the locally hardened regions on an inside passageway of the conduit. The wire guide conduit may be used in additional applications such as a control wire for an actuation system.

Claims

1. A wire guide conduit adapted for allowing movement of a core, the conduit comprising: a wire coiled in a helical manner to define the conduit and form an internal passageway of the conduit, the passageway defining a longitudinal axis, wherein the wire has a cross-section with a major axis and a minor axis, wherein a thickness of the wire along the major axis is greater than a thickness of the wire along the minor axis, wherein the wire is coiled in the helical manner to present the major axis generally parallel with the longitudinal axis of the passageway, the passageway adapted for receiving the core, wherein the wire has a straight configuration prior to being coiled and includes periodically spaced locally hardened regions having a surface hardness greater than areas of the wire outside of the locally hardened regions, wherein the locally hardened regions are disposed on an inside surface of the conduit facing the internal passageway when the wire is coiled in the helical manner.

2. The wire guide conduit of claim 1, wherein the wire consists of a single wire coiled in the helical manner.

3. The wire guide conduit of claim 1, wherein the wire has a generally elliptical cross-section.

4. The wire guide conduit of claim 1, wherein the internal passageway of the wire guide conduit defines an inner diameter, and wherein the inner diameter is constant along substantially the entire length of the conduit.

5. The wire guide conduit of claim 1, wherein the internal passageway of the wire guide conduit defines an inner diameter, and wherein the inner diameter is adapted to closely receive the core in the form of a wire having a circular cross-sectional shape.

6. The wire guide conduit of claim 1, wherein the wire has opposed first and second sides on opposite sides of the major axis and extending along the major axis and wherein the locally hardened surfaces are provided on only the first side of the wire so that when the wire is coiled to form the wire guide conduit, the first side of the wire forms the inner passageway of the conduit so that the hardened surfaces are provided only on the inner passageway of the conduit.

7. The wire guide conduit of claim 1, wherein the wire guide conduit is configured to be used in a weld wire dispensing system with the core in the form of a welding electrode wire.

8. The wire guide conduit of claim 1, wherein the locally hardened regions form a pattern along the wire when the wire is in the straight configuration.

9. The wire guide conduit of claim 8, wherein locally hardened regions are equally spaced when the wire is in the straight configuration.

10. The wire guide conduit of claim 8, wherein the pattern includes one of a series of dots, a series of stripes, a series of alternatingly inclined stripes, a series of inter-locking circles along the length of the wire, or a series of interlocking circles forming stripes across the surface of the wire.

11. The wire guide conduit of claim 1, wherein the locally hardened region is disposed within a profile of the wire when the wire is in a straight configuration such that the locally hardened region does not substantially project relative to adjacent non-hardened regions.

12. The wire guide conduit of claim 1, wherein an outside surface of the wire guide conduit does not include any locally hardened regions.

13. The wire guide conduit of claim 1, wherein the locally hardened regions are disposed at various circumferential and longitudinal locations on the inside surface of the conduit.

14. The wire guide conduit of claim 1, wherein the locally hardened regions do not extend fully across the wire along the major axis.

15. A method for forming a wire guide conduit forming an internal passageway for the passage of a core comprising the steps of: providing a wire in a straight configuration, the wire having a cross-section forming a major axis and a minor axis, wherein a thickness of the wire along the major axis is greater than a thickness of the wire along the minor axis; wherein the wire has opposed first and second sides on opposite sides of the major axis and extending along the major axis and applying an energy beam to the first side of the wire causing localized heating of a surface of the first side and creating discrete and separated areas of locally hardened regions, and coiling the wire having the locally hardened regions such that the major axis of the wire is aligned with a longitudinal axis defined by the conduit in a manner to present the locally hardened regions toward the internal passageway to form the wire guide conduit.

16. The method of claim 15, wherein the core is an electrode wire and the wire guide conduit is used for conducting the electrode wire toward a MIG welding torch.

17. The method of claim 15, wherein the energy beam is a laser producing a beam directed onto the first surface of wire.

18. The method of claim 15, wherein the beam is tightly focused and moves longitudinally relative to the wire during application of the beam, wherein the beam is a continuous wave or pulsed.

19. The method of claim 18, wherein, as the beam moves longitudinally relative to the wire, the beam is maintained at a constant lateral orientation relative to the cross-section axis of the wire during application of the beam or the beam moves laterally relative to the wire during application of the beam.

20. The method of claim 15, wherein the locally hardened regions are disposed at various circumferential and longitudinal locations on the inside surface of the conduit and no locally hardened regions are disposed on the outside surface of the conduit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 is a side cutaway view of a spring type wire guide conduit positioned in a welding torch.

[0037] FIG. 2 is a side elevational view of a wire guide conduit showing a protruding electrode wire.

[0038] FIG. 3 is a cross-sectional view of a wire guide conduit according to the present disclosure.

[0039] FIG. 4 is an end view of the conduit showing the inner passageway of the wire guide conduit.

[0040] FIG. 5 is a cross-sectional view of the wire used for forming the wire guide conduit.

[0041] FIG. 6 is an elevational view of wire for forming the wire guide conduit showing locally hardened regions along a surface of the wire.

[0042] FIG. 7 is a diagrammatic illustration of a laser surface treatment system.

[0043] FIGS. 8-11 show alternate embodiments of patterns of locally hardened regions of wire for forming a wire guide conduit.

[0044] FIG. 12 is a side elevational view of a wire guide conduit according to the present disclosure used as a control cable.

DETAILED DESCRIPTION OF THE INVENTION

[0045] Referring to FIG. 1, a representative welding torch 20 is illustrated for use in a MIG welding process. Welding torch 20 includes flexible wire guide conduit 10 formed of a coiled wire 12. In the MIG welding process, electrode wire 16 is fed through wire guide conduit 10 to protrude from torch tip 22. Electrode wire 16 can also be generally characterized as a core.

[0046] Wire 12 for forming wire guide conduit 10 has, for example, an essentially oval or elliptical cross-sectional shape (which may also be referred to as non-round). In this description, such cross-sectional shapes for wire 12 will be referred to collectively as having an oval or non-round cross-sectional shape. While the description of non-round may be used, it will be appreciated that the wire 12 may still have a rounded shape with rounded edges (for example excluding sharp edges such as those arising from a rectangular or square cross-section), and that non-round can refer to non-symmetrical shapes as well as symmetrical shapes. Accordingly, reference to non-round may also be used to signify a cross-section that is generally non-circular.

[0047] For example, as shown by FIG. 5, wire 12 of a representative shape in cross-section forms a major axis A-A and a minor axis B-B. It is understood that wire 12 does not have a circular cross-sectional shape and that the width of wire 12 along major axis A-A is greater than the width of the wire along minor axis B-B. In general, the cross-sectional shape of the wire 12 is such that the wire 12 does not have any sharp corners or flat edges. Wire 12 used to form the conduit 10 can be constructed of any material well known in the art which is used to construct conduits. For example, the wire 12 may be constructed of 1040 carbon steel and formed by drawing a source material through a forming die or roller forming tools. The non-round cross-section of the wire 12 permits the wire 12 to be wound or coiled in a controlled manner to define the conduit 10.

[0048] When wire 12 is coiled to form wire guide conduit 10, the wire is oriented such that major axis A-A is aligned along the longitudinal axis 25 of central passageway 24 of the wire guide conduit, as shown in FIG. 3. FIG. 4 is an end view of wire guide conduit 10 showing in section a view of oval wire 12. As shown in FIG. 4, the longitudinal axis 25 appears as a dot, and a cross-section of the wire 12 is shown. The orientation of the cross-section of FIG. 5 is similar to that of FIG. 3, such that axis B-B is generally aligned transverse to the passageway of the conduit 10 when the wire 12 is coiled.

[0049] As shown in FIG. 5, the non-circular or non-round wire 12 with the major and minor axis also has a width along axis A-A that is greater than a height along axis B-B. Thus, upper and lower surfaces of the wire 12 in FIG. 5 are generally longer than the side surfaces.

[0050] One advantage of using non-round wire 12 is that it can be readily oriented during the coiling operation to present a desired surface of the wire facing toward central passageway 24, a feature which is exploited in accordance with the present invention. For example, the upper surface of the wire 12 from FIG. 5 can be controlled to be the inner surface when the wire 12 is coiled into the conduit 10. Thus, the lower surface of the wire 12 in FIG. 5 can be controlled to be the outer surface of the conduit 10 when the wire 12 is coiled. A round wire, without a major and minor axis, cannot be controlled in the same way, and therefore it can be difficult to ensure that treatment applied prior to coiling the wire 12 ends up in the desired location (inside or outside the coil, depending on the treatment).

[0051] There is a broad range of specifications for wire 12 and wire guide conduit 10. In a representative specification, wire 12 has a major axis A-A dimension ranging from approximately 0.050-0.110 inch, and a height along minor axis B-B ranging from approximately 0.033-0.072 inch. Wire 12 can be formed into wire guide conduit 10 having a number of turns equaling approximately 9-20 windings per inch, depending on the wire cross-sectional dimensions.

[0052] Once coiled and formed into wire guide conduit 10, a representative configuration has an outer diameter of approximately 0.18 inches and an inner diameter for passageway 24 of approximately 0.08 inches, depending on the desired application and configuration of electrode wire 16. Of course, the thickness along axis B-B of the wire 12 will affect the difference between the inner diameter of the conduit 10 and the outer diameter of the conduit 10 when the wire 12 is coiled such that axis B-B is transverse to the longitudinal direction of the conduit 10. Various types of electrode wire 16 can be used with and fed through the wire guide conduit 10 of the present invention including various steel, aluminum and other alloys having a wide range of cross-sectional diameters. Electrode wire 16 can also be of a cored or solid type. The electrode wire 16 has an outer diameter that is less than the inner diameter of the conduit 10. The size of the conduit 10 may be selected based on the electrode wire 16 to be used, or vice versa.

[0053] In accordance with the present disclosure, wire 12, after being formed to the desired cross-sectional shape and before being coiled to form wire guide conduit 10, is subjected to a local surface heating and hardening operation. The surface hardening operation creates localized regions of increased hardness, designated in the figures as regions 18. The regions 18 may be permanently defined on the wire 12 in a variety of shapes and/or patterns in a controlled manner, such that the regions 18 may be located specifically within the passageway of the conduit 10 after winding, based on the controlled coiling afforded by the non-round cross-section of the wire 12.

[0054] Referring to FIG. 6, in one embodiment wire 12 is shown, not yet coiled, as having numerous stripes of hardened areas designated by reference number 18B. Other patterns of forming regions 18 can be provided which are described in more detail in the following discussion. As shown in FIG. 6, the stripe-shapes are arranged generally parallel to each other and are spaced apart approximately the same distance.

[0055] In a representative process, hardened areas 18 may be formed by subjecting wire 12 to laser radiation. A representative laser treatment system 26 is diagrammatically illustrated in FIG. 7. As shown, laser source 28 directs of beam 30 of radiation energy toward wire 12 shown in this figure as being supported by fixture 32. Laser energy from source 28 causes local heating of the surface of wire 12. While numerous lasers may be suitable for this application, a fiber laser outputting radiation at 1,060 nanometers is suitable in some applications. Alternatively, a CO.sub.2 gas laser could be used having an output in the 10,600 nm range. Beam 30 forms a focal spot diameter of, for example 0.05 nm. Such local heating and the subsequent quenching of the heated area causes surface hardening in a well-known manner. For example, in representative configurations, wire 12 formed of high carbon steel tempered to a hardness of 45-47 Rockwell C can be locally hardened in regions 18 to a level of about 58 Rockwell C. The surface hardening is desirably to a limited depth as shown in the cross-sectional view of FIG. 5. In one representative configuration, the hardness depth is about 0.25 nm. By forming hardened regions 18 at local areas with a limited depth, their presence does not adversely impact the formability of wire 12; allowing the wire to be coiled to form wire guide conduit 10.

[0056] Various types of lasers and processes can be used to produce regions 18. For example, wire 12 can be drawn through fixture 32 in a continuous manner with a pulsed laser directed to a surface of the wire producing a series of “dot” shaped regions 18A such as illustrated by FIG. 8. In this approach, the feed rate of the wire 12 through the fixture may be held constant, with the pulse rate also held constant to create evenly spaced dots. In another aspect, the rate of the feed or the pulse rate may be varied to create variable spacing between regions 18.

[0057] Alternatively, laser beam 30 could be swept across the diameter of wire 12 and pulsed as the wire moves continuously (at a fixed rate) through fixture 32. Such sweeping can be done by moving the axis of laser beam 30 relative to the wire cross-section or by physically moving wire 12 in a transverse direction with the laser beam axis being fixed. Put another way, the laser beam 30 moves laterally relative to the wire 12 as the wire is fed longitudinally. Such a process yields chevron shaped hardness patterns shown as regions 18B in FIG. 6. In another process, laser beam 30 is pulsed and also stroked transversely relative to the diameter of wire 12, producing an alternating inclined orientation of regions 18C as illustrated in FIG. 9.

[0058] FIG. 10 illustrates another alternative pattern for the heating effect produced by laser source 28. In this case laser beam 30 is tightly focused and cause to move in a circular pattern, for example having a circular diameter of about 3.0 nm. As wire 12 moves a chained circular configuration of a regions 18D is produced. Since the hardness pattern results in curved regions 18D is separated by unheated portions, the desired combination of locally hardened and softer annealed adjacent regions is provided. The chained circular patterns shown in FIG. 10 appears similar to a coil, but these circles 18D are on the surface of the wire 12, and the wire 12 is illustrated here prior to coiling.

[0059] FIG. 11 illustrates regions 18E produced by the same circular tracing of beam 30, but sweeping the beam across the diameter of wire 12 as it is moved continuously. Similar to FIG. 10, the illustration of FIG. 11 shows a pattern created on a surface of wire 12 that is shown flat and prior to coiling into the conduit.

[0060] These are only several example embodiments of a manner of creating locally hardened regions 18 on the surface of wire 12. As stated previously, the goal is to provide a sufficient number of hardened areas to create hardened “wear bar” regions without interfering with the ability to coil wire 12 to form wire guide 10.

[0061] Various spacing between hardened regions 18 can be provided. Referring in particular to FIG. 3, a number of the hardened regions 18 are at designated locations. It is noted that these hardened regions 18, in the configuration shown, occur at various angular positions relative to central passageway 24. It is desired that these hardened regions 18 occur at various positions both longitudinally along central passageway 24 and at different radial positions to act essentially as “wear bars” such that the electrode wire 16 will make contact with these areas as it traverses through central passageway 24 regardless of how wire guide 10 is bent.

[0062] In one aspect, with the inner surface of the conduit 10 being divided into four quadrants, hardened regions 18 are disposed on each of the four quadrants along substantially the entire length of the conduit 10. Thus, the electrode wire 16 that passes through the conduit 10 may be in contact with multiple regions 18 on various radial portions of the electrode wire 16, thereby reducing overall friction as the electrode wire 16 passes through the conduit 10 relative to a conduit without hardened portions.

[0063] In one aspect, the hardened regions 18 do not project substantially from the surface of the wire 12. Rather, as described above, the hardened regions 18 are located in a depth of the thickness of the wire 12.

[0064] In one aspect, the hardened regions 18 are limited to the interior surface of the conduit 10. In this aspect, there are no hardened regions located on the outer surface of the conduit 10.

[0065] In one aspect, the hardened regions 18 do not extend fully across the upper surface of the wire 12 when the wire is flat, and therefore do not extend into contact with adjacent coils of the conduit 10 when the wire 12 is coiled into the conduit 10. As shown in FIG. 3, the rounded shaped of the elliptical or oval cross-section creates recesses between adjacent coils of the conduit 10. Thus, the electrode wire 16 typically will not make contact with the base of these recesses. Thus, hardening areas that are ultimately disposed within the recesses may not be necessary.

[0066] As the electrode wire 16 passes through the conduit 10, the electrode wire 16 makes contact both with the hardened regions 18 as well non-hardened portions of the wire 12 that forms the conduit 10.

[0067] A design trade-off occurs as the number and size of regions 18 increases so does the likelihood of cracking or restrictions in flexibility of wire 12 as it is being coiled to form wire guide conduit 10. The optimum pattern in size for hardened regions 18 will be dependent upon numerous factors, including the materials and the sizes of wires 12 and 16, intended operational characteristics, drive systems used for advancing the electrode wire, etc.

[0068] The addition of the regions 18 to the wire 12 therefore provides advantages of a harder wire with reduced friction relative to a softer wire, but with the formability and ease of coiling made possible by the use of the softer wire 12.

[0069] Features of the present invention may also find applications for other uses. For example, illustrated in FIG. 12 is conduit 34 having cable core 36 for use as a control wire as part of an actuation system. In this case, cable core 36 typically would move in a reciprocating manner. Despite this difference, features of resistance to movement and wear are present in this application as well. In this case, wire guide conduit 34 may be formed of a non-round wire and have the local hardened regions 18 as described previously. Control cable conduit 34 can be used with clutch cables, brake cables, throttle control cables, remote mirror control cables, door latch cables, and trunk and hood latch cables, etc.

[0070] In the foregoing description, various features of the present invention are grouped together in one or more embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are incorporated by reference herein in their entirety, with each claim standing on its own as a separate embodiment of the present invention.

[0071] It is intended that the foregoing description be only illustrative of the present invention and that the present invention be limited only by the hereinafter appended claims.